Growth media

Proc Natl Acad Sci U S A, 1980 Jan, 77(1), 457 - 61
Growth and differentiation of embryonal carcinoma cell line F9 in defined media; Rizzino A et al.; This paper reports the growth and differentiation of the mouse embryonal carcinoma cell line F9 in completely defined culture media . The defined growth medium, referred to as EM-3, contains plasma fibronectin, insulin, and transferrin in place of serum . F9 cells cultured in EM-3 for over 15 generations retain their ability to form tumors and to differentiate . Fibronectin is essential for the attachment of F9 cells in defined media and its effect can be blocked with affinity-purified anti-fibronectin . When retinoic acid was added to EM-3, the F9 cells differentiated . The majority of the the newly formed cells differed from patient F9 cell two major respects: (i) they were morphologically different; and (ii) they secreted plasminogen activator, and the secretion was stimulated by dibutyrlyl adenosine cyclic monophosphate.

J Biochem (Tokyo), 1980 Jan, 87(1), 333 - 8
Effect of different growth media on the synthesis of carbohydrate-Binding protein from Dictyostelium discoideum NC-4; Yamada H et al.; The carbohydrate-binding protein, discoidin, was synthesized from Dictyostelium discoideum NC-4 grown on a Bacto peptone (Difco) containing medium together with bacteria . When the cells were transferred by serial passage to a Proteose peptone (Daigo)-containing medium, the productivity of discoidin was reduced to a negligible amount, but the cells formed aggregates, and another protein which binds with Sepharose 4B was detected by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate . We conclude that discoidin synthesis is already regulated during growth, and even when the amount of this protein is nil or negligible, the cells still retain aggregate-forming ability.

Z Mikrosk Anat Forsch, 1980, 94(4), 661 - 8
{Effect of substance P on nerve fiber regeneration in tissue culture}; Lindner G et al.; Explants of the ganglion trigeminale from chick embryos (PNS) and of the hippocampus from fetal rats (CNS) were cultivated in maximow chambers with growth medium or maintanance medium . Varied concentrations of substance P (SP . 3 CH3COOH . 4 H2O) were added . 1 . The effect of substance P (SP) is related to concentration . In the presence of 10(-7)M SP in the growth medium and of 10(-4)M SP in the maintanance medium the cultivation of PNS cultures indicates positive results . These doses are suitable . 2 . Within the first 24 hours in vitro SP stimulates the index of area in PNS cultures . The index of characterizes the relation of the outgrowth zone to the explant . In CNS cultures a significant difference of this effect was not observed . 3 . The index of growth of nerve fibers may compare the test cultures with the control cultures . SP significantly increases the index of fiber growth in PNS cultures . A stimulation of CNS cultures was observed, significance was not found . 4 . From the beginning of the cultivation with SP up to 48 hours in vitro the growth of nerve fibers significantly increases in the treated cultures in comparison with the control cultures . After this time the growth of nerve fibers decreased and a morphological conformity of test cultures and controls was observed . 5 . The role of SP is discussed in specific activity on PNS tissue in vitro . The reactive neurons may be from the medio dorsal group of cells of the sensible ganglion.

Ciba Found Symp, 1980, 79, 163 - 82
Copper and the synthesis of elastin and collagen; Harris ED et al.; Copper's role in connective tissue is linked to the enzyme lysyl oxidase . From a biochemical perspective, copper is a cofactor for the enzyme and a determinant of its activity in connective tissues . Lysyl oxidase catalyses a post-translational oxidation of certain lysine and hydroxylysine residues . The peptidyl aldehydes so formed become active centres for the formation of cross-links in collagen and elastin . Less well understood is how copper controls the steady-state activity of lysyl oxidase; the enzyme fails in copper deficiency . Giving copper to a deprived animal increases lysyl oxidase activity in aortic tissue . Such activation in vivo appears to require caeruloplasmin . Suspending aortic tissue in a copper-enriched growth medium also activates lysyl oxidase provided that tissue structure is kept intact . Activation in vitro occurs with the binding of copper to a large-molecular-weight component, presumably the enzyme . Binding will not occur if protein synthesis is blocked . These studies clearly show that the synthesis of mature elastin and collagen can be controlled by the availability of copper . They further suggest that transport of copper to aortic tissue and its engagement to lysyl oxidase are linked to the synthesis or lysyl oxidase, an extracellular carrier, or both.

J Gen Virol, 1979 Dec, 45(3), 599 - 610
The influence of arginine starvation on the synthesis of virus high molecular weight DNA in HeLa cells productively infected by adenovirus type 5; Kumel G et al.; In culture cells productively infected by adenovirus a high mol . wt . form of DNA is synthesized which is known to represent, at least in part, virus DNA integrated into cellular DNA . We found that the synthesis of this high mol . wt . DNA and the other DNA size classes can strongly and differentially be influenced by altering the metabolic state of the cells . The effects of different rates of cell growth were tested in this respect as well as arginine deprivation as opposed to application of complete growth medium . Synthesis of virus high mol . wt . DNA and unit genome length DNA is enhanced in actively growing as compared to resting Ad5-infected HeLa cells . Under arginine deficiency, in resting Ad5-infected HeLa cells, integration of virus DNA sequences into cellular DNA is almost totally suppressed whereas virus unit genome length DNA is still synthesized . This differential effect is interpreted by the hypothesis that the formation of virus high mol . wt . DNA is a synthetic process that is independent of the unit size virus DNA replication, but coupled to the synthesis of a special form of a special form of cellular DNA that is less effectively shut off by the infection than cellular DNA in general.

J Cell Sci, 1979 Dec, 40, 125 - 44
Quantitative replicon analysis of DNA synthesis in cancer-prone conditions and the defects in Bloom's syndrome; Ockey CH; A quantitative method of replicon analysis of DNA fibre autoradiographs has been used to study the relationship between mean rate of DNA chain growth (R) and distance between adjacent replicons (ID) in fibroblasts from cancer-prone conditions . Results are expressed in terms of the mean linear regression R = delta +(K.ID)10-2 . When replicon behaviour was examined in cells from patients with ataxia telangiectasia, basal cell naevus and Bloom's syndromes grown at high density after 48 h in culture, no significant differences could be found in replicon behaviour between these syndromes and normal cultures . However when Bloom's cells were grown at low density and examined 24 h earlier, the mean rate of chain growth R was reduced compared to normal cells at the same density . Both cell types at high densities at 24 h showed equal but lower R values than at 48 h after plating the cultures . The lower rate of chain growth in Bloom's was accompanied by a longer S-period and cell cycle . Studies of cell proliferation kinetics using consecutive mitoses after bromodeoxyuridine (BUdR) incorporation and harlequin banding showed that Bloom's cells at low cell density require a longer period to recover a normal cell cycle length after plating than do normal cells at the same density . Plating densities and using conditioned media shorten the recovery period in Bloom's cells, and when foetal calf serum/MEM is replaced by human AB serum/McCoy 5a medium as the growth media, cell cycle behaviour of low density Bloom's and normal cells are equal at a much earlier time . It is concluded that the slow rate of DNA chain growth in Bloom's cells is an artefact introduced by culture conditions and also may be present in normal cells at an earlier period . The behaviour of replicons during this recovery period appears to be similar in Bloom's and normal cells except for the time lag . As recovery proceeds, the DNA chain growth in the associated replicon pairs recover progressively . This alters both the mean R value from 0.4 to 0.8 micron/min, the slope of the regression K from less than 1.0 to approximately 1.0 while the distance between initiation sites (ID) remains constant throughout . Pretreatment of all cultures with fluorodeoxyuridine (FUdR) produced the same differential effect on release from DNA synthesis inhibition, that is a similar increase in the activation of normally inactive replicons and a slightly slower rate of chain growth over all replicons . No evidence of a substance released by Bloom's cells in culture capable of increasing the sister-chromatid frequency in normal cells could be found . Since SCE frequencies were found to increase with fixation time after BUdR introduction it is concluded that some of the reported changes could be due to differences in cell cycle kinetics brought about by the different media conditions.

J Bacteriol, 1979 Dec, 140(3), 843 - 7
Influence of molecular size and osmolarity of sugars and dextrans on the synthesis of outer membrane proteins O-8 and O-9 of Escherichia coli K-12; Kawaji H et al.; Supplementation of the growth medium with high concentrations of sugars or low-molecular-weight dextrans results in a drastic change in the ratio of outer membrane proteins O-8 and O-9, due to induction of O-8 synthesis and suppression of O-9 synthesis . Sugars and dextrans of molecular weights greater than 600 to 700 switched the synthesis of O-9 to that of O-8 more effectively than those of lower molecular weight, although the effect was almost the same within each of the two groups irrespective of the differences in molecular weight within the group . Proteins O-8 or O-9, or both, are responsible for the formation of pores that allow the passive diffusion of hydrophilic molecules whose molecular weights are smaller than about 600 (T . Nakae, Biochem . Biophys . Res . Commun . 71:877-884, 1976) . The results indicate that substances that cannot pass through the outer membrane switch the synthesis of O-9 to that of O-8 more effectively than those that can penetrate this membrane with the aid of O-8, O-9, or both . It is suggested that the osmotic pressure exerted on the outer membrane plays an important role in the regulation of synthesis of the two proteins.

Z Naturforsch {C}, 1979 Dec, 34(12), 1177 - 85
Expression of aspartokinase, dihydrodipicolinic acid synthase and homoserine dehydrogenase during growth of carrot cell suspension cultures on lysine- and threonine-supplemented media; Matthews BF et al.; Reduction in the amounts of activity of the first enzyme, aspartokinase (EC 2.7.2.4) and two branch-point enzymes, dihydrodipicolinic acid synthase (EC 4.2.1.52) and homoserine dehydrogenase (EC 1.1.1.3), located in the pathway for the synthesis of aspartate-family amino acids, occurred when cell suspension cultures of Daucus carota L . var . Danvers were grown in media containing 2 mM threonine or 2 mM lysine, endproducts of the pathway . Activity of the lysine-sensitive form of aspartokinase was decreased when cells were grown in medium containing lysine and the activity of the threonine-sensitive form was decreased when cells were grown in medium containing threonine . Activity of the branch-point enzyme leading to threonine synthesis, homoserine dehydrogenase, was decreased up to 70% in specific activity (units/mg protein) and relative activity (units/g fresh weight) when cells were grown in media containing lysine or threonine . Threonine had no effect on the relative activity of dihydrodipicolinic acid synthase, but decreased its specific activity . Lysine decreased the relative activity of the synthase by up to 40%, but had little effect on its specific activity . The decreased activities of the enzymes were apparently not due to binding of the inhibitory amino acids to the enzymes since homogenization of cells in buffer with 2 mM lysine and threonine did not decrease the measurable enzyme activities . These and other results presented suggest that both forms of the aspartokinase activity and homoserine dehydrogenase activity can be altered by supplementing the growth medium with lysine or threonine.

Infect Immun, 1979 Dec, 26(3), 925 - 32
Novel iron uptake system specified by ColV plasmids: an important component in the virulence of invasive strains of Escherichia coli; Williams PH; The enhanced virulence of invasive strains of Escherichia coli carrying ColV plasmids was shown to be due to a novel plasmid-mediated iron uptake system . Possession of a ColV plasmid conferred strong selective advantage on the host bacterial strain in experimental infections unless excess iron was administered in the inoculum . Moreover, supplementation of defined minimal medium with transferrin to complex available iron caused marked limitation of the growth of plasmid-free strains but had no effect on strains carrying a ColV plasmid . The activity of an efficient iron uptake process was clearly shown by experiments with a mutant of E . coli deficient in enterochelin biosynthesis . Although the mutant was dependent on the presence of citrate in the growth medium to facilitate iron transport, colicinogenic derivatives did not require added citrate for growth . Radioactive iron was shown to be taken up rapidly by nongrowing cells of the plasmid-carrying strain . Furthermore, it was observed that repression of the synthesis of specific outer membrane proteins normally induced by conditions of iron deficit was maintained after a shift of the colicinogenic strains from a rich medium to a medium low in iron . The ColV plasmid-mediated iron uptake system was independent of the active iron transport mechanisms known in E . coli, but like them it required tonB activity as a source of energy.

J Gen Microbiol, 1979 Dec, 115(2), 517 - 21
Preparation of protoplasts and whole cell ghosts from Mycobacterium smegmatis; Rastogi N et al.; Cell wall-deficient forms of Mycobacterium smegmatis were produced in growth medium containing D-cycloserine and horse serum . These cells were transformed into protoplasts with EDTA and lysozyme . Subsequent lysis by nucleases followed by osmotic shock produced membrane vesicles (whole cell ghosts).

Antimicrob Agents Chemother, 1979 Dec, 16(6), 838 - 48
Triggering of autolytic cell wall degradation in Escherichia coli by beta-lactam antibiotics; Kitano K et al.; A biochemical method was developed to quantitatively compare the effectiveness of beta-lactams in triggering murein degradation (autolysin activity) in Escherichia coli . Bacteria prelabeled in their cell walls with radioactive diaminopimelic acid in growth medium were exposed for 10 min to the antibiotics at the appropriate minimal growth inhibitory concentrations and at multiples of these values, and the rate of cell wall degradation was followed during subsequent penicillin-binding protein (PBP)-1 were the most effective triggers of autolytic wall degradation; beta-lactams selective for PBP-2 were the poorest; and antibiotics preferentially binding to PBP-3 showed intermediate activities . The relative effectiveness of beta-lactams in autolysin triggering was found to parallel the effectiveness of the same drugs in causing rapid loss of viability, culture lysis, and spheroplast formation . Autolysin triggering was suppressed by inhibitors of protein and ribonucleic acid biosynthesis but not by inhibitors of deoxyribonucleic acid synthesis . The beta-lactam-induced cell wall degradation did not seem to involve a direct stimulation of enzyme activity or synthesis of new enzyme molecules, and murein sacculi isolated from cells that had been preexposed to a triggering dose of beta-lactam treatment exhibited the same sensitivity to crude, homologous autolysins as sacculi prepared from untreated control bacteria . On the basis of these observations, mechanisms are considered for the triggering of E . coli autolysins and for the role of autolytic activity in bacterial spheroplast formation, lysis, and death.

Virchows Arch B Cell Pathol Incl Mol Pathol, 1979 Dec, 32(1), 47 - 56
Lowered resistance to lytic agents in sucrose vacuolation; Benassi G et al.; Vacuolation in fibroblasts cultivated in the presence of sucrose is associated with progressive accumulation of the undigestible sugar . In radioisotope experiments the process lasted several days, and when the cells were subcultured back into a medium devoid of sucrose the label was also lost after several days . This type of vacuolated cells is more fragile when it is challenged with lytic agents . 51Cr-labelled LS fibroblasts released more radioactivity when they had been growing in the presence of sucrose, whether they were suspended in media of decreasing osmolarity, in dilutions of various surfactants, exposed to high temperatures, or subjected to mechanical stress . It is concluded that these cells exhibit a lower resistance when exposed to unfavourable environments, but retain their viability in growth media despite some morphological and biochemical alterations.

Biochem J, 1979 Nov 15, 184(2), 409 - 19
Two forms of 'malic' enzyme with different regulatory properties in Trypanosoma cruzi; Cannata JJ et al.; 1 . Cell-free extracts from culture epimastigotes of Trypanosoma cruzi contained two forms of NADP+-linked 'malic' enzyme (EC 1.1.1.40), I and II, with the same molecular weight but different electrophoretic mobilities and kinetic and regulatory properties . 2 . The apparent Km for L-malate was lower for 'malic' enzyme I, with hyperbolic kinetics, whereas the kinetic pattern for 'malic' enzyme II was slightly sigmoidal (h 1.4) . The kinetics for NADPH were hyperbolic for 'malic' enzyme I, and very complex for 'malic' enzyme II, suggesting both positive and negative co-operativity . 3 . 'Malic' enzyme II was markedly inhibited by adenine nucleotides; AMP was the the most effective, at least in the presence of an excess of MnCl2 . 'Malic' enzyme I was much less affected by the nucleotides . Both enzyme forms were inhibited by oxaloacetate, competitively towards L-malate, but the apparent Ki for 'malic' enzyme I (9 microM) was 10-fold lower than the value for 'malic' enzyme II . 'Malic' enzyme II, but not 'malic' enzyme I, was activated by L-aspartate and succinate (apparent Ka of 0.12 and 0.5 mM respectively); the activators caused a decrease in the apparent Km for L-malate and, to a lesser extent, in the apparent Km for NADP+ . L-Aspartate, but not succinate, increased the apparent Vmax . 4 . The inhibition by AMP suggests regulation by energy charge, with the L-malate-decarboxylation reaction catalysed by 'malic' enzyme II fulfilling a biosynthetic role . The inhibition by oxaloacetate and the activation by succinate are probably involved in the regulation of the 'partial aerobic fermentation' of glucose which yields succinate as final product . The activation by L-aspartate would facilitate the catabolism of this amino acid, when present in excess in the growth medium.

Mutat Res, 1979 Nov, 63(1), 21 - 34
Effects of spermine on the detection of induced forward mutation at the Can1 locus in yeast: evidence for selection against canavanine-resistant mutants; McDougall KJ et al.; The effect of exogenous spermine tetrahydrochloride (0.5 mg/ml) on hydrazine- and nitrous acid-induced forward mutation to canavanine resistance (CAN1 leads to can1, normal to defective arginine permease) was examined in stationary-phase haploid Saccharomyces cerevisiae . Post-treatment cell division (specifically DNA replication) is required for hydrazine mutagenesis at this locus, whereas nitrous acid mutagenesis exhibits, in addition, a significant post-treatment-independent component . Spermine addition only during mutagenic treatments in buffer did not affect mutagen cytotoxicity, but did result in a slight yet consistent decrease in induced mutation frequencies . Addition of spermine to the yeast extract--peptone--dextrose (YEPD) post-treatment growth medium resulted in dramatic reductions of induced mutation frequencies, which could be alleviated by pregrowth in spermine-containing YEPD . Such a medium was found to cause an apparent temporary growth inhibition for almost 40 h, after which the growth rate of the culture increased rapidly . Cultures "recovering" from spermine inhibition were no longer inhibitable by spermine in fresh medium, suggesting an outgrowth of spontaneous and/or induced spermine-resistant derivatives . Genetic analysis of one isolate revealed a single dominant nuclear gene conferring resistance by some means other than defective spermine uptake . Growth of this mutant was only slightly inhibited by spermine (20% increase in doubling time), while mutation expression remained high . Results of competitive growth experiments indicated that spermine-containing YEPD exerted a selection pressure against canavanine-resistant cells, while YEPD by itself did not . The mechanism for this selection is not presently understood . With respect to replication-dependent induced mutation at CAN1, our initial observation of a strong apparent antimutagenic action of spermine was found to be best explained by this specific selection against can1 mutants . This underscores the need for caution in the interpretation of experiments designed to study physiological modification of mutagenic potential.

Proc Natl Acad Sci U S A, 1979 Nov, 76(11), 5992 - 6
Migration of Schwann cells and wrapping of neurites in vitro: a function of protease activity (plasmin) in the growth medium; Kalderon N; In vitro conditions were defined under which Schwann cells, from a population of dissociated embryonic chicken spinal cord cells, migrate along the growing neuronal fibers and wrap bundles as well as individual axons, in a pattern similar to that found in a developing peripheral nervous system in vivo . The migration of Schwann cells and their wrapping of nerve fibers was found to be a function of plasmin activity in the growth medium . It was determined that at least one cell type among the spinal cord cells is producing plasminogen activator, the enzyme that activates the plasminogen that is a constituent of any serum . It is concluded that, to achieve wrapping of neurons by Schwann cells in culture, it is essential to have an active plasmin-generating system in the medium . It is hypothesized that the Schwann cell produces plasminogen activator . The possible role of both the Schwann cell and the plasminogen possible role of both the Schwann cell and the plasminogen activator in the formation of the neuromuscular junction is discussed.

J Protozool, 1979 Nov, 26(4), 586 - 8
Extrusion of DNA from the macronucleus of Tetrahymena pyriformis GL; Lykkesfeldt AE; Administration of the thymidine analog 5-bromodeoxyuridine to exponentially growing cultures of Tetrahymena pyriformis GL in chemically defined medium results in inhibition of cell multiplication by at least one generation before DNA synthesis stops . Cell multiplication can be restored in these cultures, if they are transferred to fresh growth medium, but although most of the cells in the culture contain close to a G2-amount of DNA, a full DNA replication round is a prerequisite for renewed cell multiplication . Large extrusion bodies are found at the first division after transfer to fresh growth medium . Autoradiographic analysis has revealed that the DNA in the extrusion body is a representative of the DNA in the macronucleus indicating a random distribution of DNA between daughter nuclei and extrusion body.

Biochem J, 1979 Oct 15, 184(1), 45 - 50
Synthesis of cytoplasmic membrane during growth and division of Escherichia coli . Dispersive behaviour of respiratory nitrate reductase; Cadenas E et al.; We have used the penicillin selection method of Autissier & Kepes {(1972) Biochimie 54, 93--101} to study the segregation of membrane-bound respiratory nitrate reductase (EC 1.9.6.1) in Escherichia coli for the three generations after cessation of nitrate reductase synthesis caused by withdrawal of nitrate from the growth medium . We also included a physical separation procedure that permitted direct assay for nitrate reductase activity among all fractions produced by the penicillin selection method . We conclude that the segregation of nitrate reductase after cell division is dispersive, and not semi-conservative as proposed by Autissier & Kepes (1972).

Nucleic Acids Res, 1979 Oct 10, 7(3), 765 - 79
Production of specific site probes of tRNA structure by enrichment with carbon 13 at particular locations; Tompson JG et al.; Escherichia coli C6 rel met cys was cultured in a stringently defined minimal medium containing 13C-enriched metabolites in order to (1) achieve maximal 13C isotopic enrichment of tRNA; and (2) produce site specific but natural, non-perturbing NMR probes of tRNA structure and function . Growth conditions were manipulated to achieve optimal culture growth concomitant with maximal in vivo incorporation of various 13C-enriched nucleic acid precursors, including L-{methyl-13C} methionine, {2-(13)C} adenine, and {2-(13)C} uracil . Effective blockage of purine biosynthesis de novo was accomplished with the addition of the antimetabolite 6-mercaptopurine to the growth medium . Transfer RNAs specifically 13C-enriched in all methyl groups (57 atom %), C2 of adenine (60 atom %), and C2 of uracil (82 atom %) and C2 of cytosine (73 atom %) have been produced.

J Cell Physiol, 1979 Oct, 101(1), 57 - 65
Trace element uptake by L-cells as a function of trace elements in a synthetic growth medium; Zombola R et al.; The concentration of trace elements in L-cells has been studied as a function of the trace metal content of the growth medium . Cells were cultured in synthetic media which contained varying trace amounts of the elements manganese, iron, cobalt, copper, zinc and molybdenum . The cellular concentration of the of the elements potassium, iron, copper and zinc were then determined . It was found that the cell accumulates trace metals at a different rate than they are made available . Deficiencies in zinc could be "induced" in the cell by increasing the concentration of iron, manganese and cobalt; cellular iron deficiencies were observed at larger medium concentrations of zinc, manganese, copper and cobalt . Trace metal uptake by the cell was seen to parallel the utilization by multicellular organisms.

Cornell Vet, 1979 Oct, 69(4), 411 - 25
Trypanosoma theileri: a literature review and report of incidence in New York cattle; Schlafer DH; The incidence of infection in adult dairy cattle in New York State with Trypanosoma (Megatrypanum) theileri (Laveran 1902) was determined by culturing buffy coats of peripheral blood samples in tissue culture growth media . Three sample groups of cattle were studied and revealed an overall rate of trypanosome infection of 44.4% (67 of 151) as determined by a single culture . Fifty-seven cows, representing four herds from three different geographic locations in the Southern-tier region of the state, comprised the first group . The infection rates of these herds ranged from 56.5 to 100% . The second group consisted of 81 cows randomly selected from animals admitted to the Large Animal Clinic of the New York State College of Veterinary Medicine . Trypanosoma theileri was cultured from 25.9% (21 of 81) of these animals . Repeated blood cultures from a third group of thirteen yearling heifers during the spring and summer revealed an increase in the infection rate from 0% in May, to 66.7% (8 of 12) in September, with 76.9% (10 of 13) positive at least once during this period . These findings are compared with the reported incidence of bovine T . theileri infections in other areas of the United States and in other countries.

Arch Biol Med Exp (Santiago), 1979 Oct, 12(3), 359 - 66
Regulation of collagen synthesis and maturation by 3,4-dehydroproline; Kerwar SS; Proline analogs are readily incorporated into collagen and noncollagen proteins . Since the imino acid content of collagen is greater than other proteins, it is suggested that the incorporation of a proline analog into cellular protein would have a maximal effect on collagen metabolism . Using a partially purified amino acyl tRNA synthetase preparation, various proline analogs were tested for their ability to inhibit Pro-tRNA synthesis . Amongst those tested, dehydroproline was the preferred inhibitor . Dehydroproline was also a substrate for amino acyl tRNA synthetase . When dehydroproline was added in vitro to membrane bound polysomes, the synthesis of collagenous proteins was preferentially inhibited . The addition of dehydroproline to mammalian cell cultures caused a marked reduction in prolyl hydroxylase activity . Under these conditions growth of cells, activities of lysyl; hydroxylase or lactic dehydrogenase were not affected . Reduction of prolyl hydroxylase activity by dehydroproline required protein synthesis . Removal of dehydroproline from the growth medium resulted in an increase in prolylhydroxylase activity . Hepatic fibrosis can be induced in rats by chronic administration of carbon tetrachloride . Under these conditions, the collagen content and prolyl hydroxylase activity of the liver is enhanced . Treatment of these fibrotic animals with dehydroproline results in a reduction of prolyl hydroxylase activity of the liver . A mechanism by which dehydroproline reduces prolyl hydroxylase activity will be discussed . Since prolyl hydroxylase plays a key role in the maturation and deposition of collagen, specific inhibitors of this enzyme are potentially useful in controlling collagen deposition in various pathological conditions.

J Cell Sci, 1979 Oct, 39, 383 - 96
Intracellular distribution of lead in Tetrahymena during continuous exposure to the metal; Nilsson JR; Lead acetate (0.1--0.2%) forms a precipitate with the organic growth medium . The Tetrahymena cells ingest this lead-containing precipitate and cell growth is resumed after a variable lag period . Ingested lead is observed as electron-dense material in food vacuoles . Soon after exposure, cytoplasmic lead (preserved with certain fixation only) is revealed as electron-dense particles in cilia and in a halo around digestive vacuoles . Later the lead particles pervade the entire cell but after the lag period they are confined to membrane-bound spaces . In dilute growth medium, high concentrations of lead inhibit food-vacuole formation and cell growth . Under these conditions lead is deposited in alveoli of the pellicle and is also found in autophagic vacuoles and other membrane-limited structures . The study has revealed that lead enters Tetrahymena through the membrane of digestive vacuoles and through the cell surface . The change in distribution of lead during the lag period indicates that a mechanism is activated for removal of lead into membrane-bound spaces . The final storage of lead seems to be in lysosomes.

Infect Immun, 1979 Oct, 26(1), 70 - 5
Adherence of Mycoplasma pneumoniae to glass surfaces; Feldner J et al.; Attachment of M . pneumoniae to glass was quantitated in an experimental system enabling the settling down of {3H}palmitic acid-labeled cells onto glass cover slips . Attachment of mycoplasmas suspended in buffer increased with temperature, decreased with higher ionic strength, and showed a maximum at about pH 5.5 . The findings suggest a participation of ionic bonds in the attachment process . Trypsin did not detach glass-bound mycoplasmas, and treatment of the cells with glutaraldehyde did not reduce their attachment to glass, suggesting that membrane components other than proteins may be involved in the attachment . Low concentrations (up to 20 mg/ml) of bovine serum albumin buffer . However, during the next few hours, attachment increased far above the bovine serum albumin control . This marked increase was reduced by more than half in the presence of chloramphenicol . Increased attachment was also observed when glucose (0.1 to 2 mg/ml) was added to the bovine serum albumin-containing buffer . The findings suggest different mechanisms for the attachment in protein-free buffer and in growth medium or glucose-containing bovine serum albumin buffer, respectively . The latter apparently requires metabolic activity of the mycoplasmas.

Biochem J, 1979 Sep 15, 182(3), 847 - 59
Mechanisms of protein degradation in growing and non-growing L-cell cultures; Amenta JS et al.; L-cells prelabelled with {14C}leucine and {3H}thymidine were placed in either fresh growth medium (minimal essential medium with 10% serum) or stepdown medium (minimal essential medium) for 3 days . The 14C/3H ratio remained constant in the growing cultures and decreased in the stationary-phase cultures, indicating no protein turnover in growing cultures and a degradative rate of 0.6%/h in the stationary-phase cultures . Media analysis, however, indicated that 14C-labelled proteins were being degraded at approx . 1.2%/h in growing cultures and 1.7%/h in stationary-phase cultures . Additional studies indicated that a subpopulation of L-cells in the monolayer, comprising approx . 20--30% of the total, were lost in the original processing procedure . Experiments in which recoveries approached 100% by fixation of the monolayer in situ indicated that a protein-degrading subpopulation accounted for all the observed proteolysis in the growing cultures . Proteolysis in these cultures was only partially inhibited with NH4Cl, indicating that only a small part of the protein degradation was occurring in an activated lysosomal-autophagic system . NaF produced a more effective inhibition of proteolysis, but we were not able to distinguish whether this effect was on an ATP-requiring basal-turnover mechanism or a direct effect on unregulated activity of proteinases in the cell hyaloplasm . However, NH4Cl inhibited the proteolysis induced when cells were placed in stepdown medium, suggesting that the induced proteolysis was occurring via the autophagic system . We conclude that L-cells exist in at least two states with respect to protein degradation: (a) a subpopulation that is actively replicating and does not degrade cellular proteins, and (b) a second subpopulation of cells, derived from the preceding one, which degraded most of their labelled proteins, are not capable of further replication, and are not sedimented in an iso-osmotic EDTA buffer solution . In addition, proliferating L-cells, when placed in stepdown medium, begin to degrade cell protein through a mechanism involving autophagolysosomes.

Int J Cancer, 1979 Sep 15, 24(3), 336 - 40
Transformation of feline embryo cells in culture by a chemical carcinogen; Rhim JS et al.; A feline embryo cell line was treated in vitro with various levels of 7,12-dimethylbenz{a}anthracene (DMBA) or dimethyl sulfoxide (control) . Repeat treatment of DMBA only induced in vitro transformation of feline embryo cells following clonal growth and selection . The morphologically altered cells formed large cell aggregates and grew in this aggregate form when suspended in liquid growth medium above an agar base, formed colonies in soft agar, and grew to high saturation densities . However, no progressively growing tumors were produced when cells were inoculated into nude athymic mice . The transformed lines were negative for feline oncornavirus-associated cell membrane antigen (FOCMA).

J Cancer Res Clin Oncol, 1979 Sep, 95(1), 29 - 37
Control of in vitro cytotoxicity of positively charged liposomes; Panzner EA et al.; The parameters which influence the in vitro cytotoxicity of positively charged liposomes for L 1210 cells were analyzed . The cytotoxicity was liposome/cell ratio-dependent . It also depended upon the mole fractions of stearylamine (SA) to phosphatidylcholine (PC) . There was no difference between the cytotoxicity of unilamellar and multilamellar vesicles but the cytotoxic effect of free SA was about 4 times greater than that of liposome incorporated SA at a molar ratio of 1:4, SA:PC, respectively . The process which resulted in cell death was irreversible after 60 min of cell-liposome contact . The simultaneous presence of neutral liposomes or of positively charged liposomes with a lesser charge density decreased the cytotoxic effect of liposomes with a higher SA content . The cytotoxicity could be decreased by trypsinization of cells following exposure to liposomes while treatment of cells with trypsin prior to the exposure to positively charged liposomes had no effect on the subsequent cytotoxicity . The cytotoxicity was also decreased if cells were incubated in the presence of sodium azide . The usual concentration of serum (10%) present in the growth medium had no effect on the cytotoxicity while preincubation of cells with liposomes in 80% serum resulted in full protection . The protective effect of serum could be replaced by the albumin fraction.

Cancer Res, 1979 Sep, 39(9), 3661 - 72
Quantitative models for growth inhibition of human leukemia cells by antitumor anthracycline derivatives; Kanter PM et al.; A batch elution method with hydroxylapatite was developed to assay DNA damage by a set of antitumor anthracycline derivatives and was standardized with respect to the kinetics of unwinding, size of the alkaline unwinding unit, and fidelity of selective elution of single and double-stranded DNA . The method was applied to a study of a set of 10 antitumor anthracycline derivatives which inhibit growth of CCRF-CEM human leukemia cells over a range of potencies exceeding four orders of magnitude . The derivatives, including Adriamycin, daunorubicin, and carminomycin, vary in structure at C-4 and C-13, with substitutions at C-14 and N and stereochemical differences at C-4' . In a static model (fixed drug concentrations and incubation times), the potency {1/ID37 (concentration of agent that inhibits cell growth by 37%)} of nine of the ten derivatives may be expressed as functions of DNA damage (n), inhibition of thymidine incorporation (l), and drug retention (r): ID37 = Ka(r/l . n)kb, with a coefficient of correlation of greater than 0.99 . A kinetic model with 4-demethoxydaunorubicin (varying concentrations and incubation times) was also described . Following initial uptake and a period of rapid loss after cells are washed free of excess drug, the change in agent concentration in the cells follows first-order kinetics . The cell index (cell number after 50 hr in drug-free growth medium/cell number after initial 2-hr exposure with drug) may be expressed linearly in terms of the kinetics of drug loss (coefficient of correlation, greater than 0.98), or as functions of 1/n (coefficient of correlation, greater than 0.958), 1/l . n (coefficient of correlation, greater than 0.963, or r/l . n (coefficient of correlation, greater than 0.963) . These studies may be used to define a class of similarly acting anthracycline agents and to give some insight into the mechanism of action of the agents that fall within the class.

J Med Chem, 1979 Sep, 22(9), 1104 - 9
Anticandidal activity of 5-fluorocytosine-peptide conjugates; Steinfeld AS et al.; An approach to the development of new anticandidal drugs is described that employs peptides as carriers of toxic agents into cells . 5-Flurorcytosine (5-FC) was chosen as a toxic agent with which to prepare 5-FC-peptide conjugates as models to test the carrier proposal . Model compounds were synthesized and then tested for antiyeast activity against S . Cerevisiae 9763, C . albicans 1-V, C . albicans WD 18-4, and C . Krusei 1-T . The 5-FC derivatives showed antiyeast activity comparable to 5-FC in all strains except C . krusei 1-T, in which case the compounds were less active . The solution stabilities of 5-FC conjugates at 37 degrees C were tested in the same growth medium used for susceptibility testing . The results indicated a range of stabilities where the half-life (t1/2) = 0.3--17.6 h . These results and those obtained in the susceptibility testing suggest extracellular hydrolysis and indicate that the type of linkage used to conjugate 5-FC to peptides will not provide appropriate compounds to evaluate the peptide-carrier concept.

J Biol Chem, 1979 Aug 25, 254(16), 8067 - 73
The isolation and amino acid/sugar composition of human fibroblastoid interferon; Tan YH et al.; Human fibroblastoid interferon produced from an established human cell line was purified by controlled-pore glass and concanavalin A-Sepharose column chromatography followed by preparative two-dimensional gel electrophoresis . The purification procedure provided a 10% recovery of pure interferon with good reproducibility . The purified protein was homogeneous with respect to its molecular weight of 20,000 and net electrical charge at pH 2.5 . Interferon of high specific activity of 5 x 10(8) units/mg of protein was directly demonstrated in the polyacrylamide gel before staining with Coomassie brilliant blue . Parallel purification of a sham-induced interferon preparation did not yield an equivalent product indicating the purified interferon is not derived from uninduced cells or from the fetal calf serum of the tissue culture growth medium . Pure interferon was radioiodinated by Bolton-Hunter reagent . Amino acid analysis of the pure preparation shows interferon to be a leucine-rich glycoprotein containing a high percentage of glutamic/glutamine residues and that disulfide bridges(s) are important for its biological activity.

Eur J Biochem, 1979 Aug 15, 99(1), 1 - 7
Level and turnover of polyadenylate-containing ribonucleic acid in Neurospora crassa in different steady states of growth; Sturani E et al.; Mycelia of Neurospora crassa in a steady state of growth in different media have a ribosomal content proportional to the rate of growth . Moreover, both the percentage of polysomes and the average ribosomal activity are about the same at all different growth rates . The content of polyadenylated RNA was determined in three different conditions of exponential growth, which allowed growth rates that ranged from 0.26 to 0.51 duplications/h, and was found to constitute about the same fraction of total RNA (4.5--5.2%) . Using a kinetic approach, an equation was derived which allowed determination of the average half-lives of polyadenylated RNA: in each medium the cultures were labeled from the moment of the inoculation with {32P}orthophosphate and were then given a 10-min pulse with {5-3H}uridine when they were in the exponential phase . It was found that the determined half-lives of polyadenylated RNA vary, depending on the growth medium, between 30 and 60 min, but with no direct correlation with the growth rate . Moreover, the rate of synthesis of polyadenylated RNA relative to that of stable RNA decreased with the growth rate . On the basis of previous data on the rates of synthesis of stable RNA, it was possible to make an evaluation of the absolute rate of synthesis of polyadenylated RNA . Whereas the rate of synthesis of stable ribosomal RNA increases as a function of the square of the number of duplications per hour, the increase in the rate of synthesis of polyadenylated RNA with the growth rate is much less consistent . It is concluded that in Neurospora the growth rate does not depend on the rate of synthesis of mRNA but rather on the rate of synthesis of rRNA, which sets both the ribosomal level and the steady-state level of mRNA.

Int J Cancer, 1979 Aug, 24(2), 225 - 34
Importance of a collagen substratum for stimulation of capillary endothelial cell proliferation by tumour angiogenesis factor; Schor AM et al.; Tumour extracts were obtained from rat Walker 256 carcinoma and examined for the presence of tumour angiogenesis factor (TAF) in vivo before being used in tissue culture experiments . Capillary endothelial cells derived from cow brain white matter were used to study the effects of TAF-containing tumour extracts on cell proliferation in vitro . The cells were grown on two types of substrata: (1) plastic tissue culture dishes and (2) hydrated gels made of rat tail tendon type I collagen . Human platelets or platelet-released factors were introduced into the system because of the many inter-relationships known to exist between platelets, collagen and endothelial cells . If trypsin was used during the preparation of TAT, the resulting batches stimulated endothelial cell proliferation only when the cells were growing on a collagen substratum and either platelets or platelet-released factors were present in the growth medium . If incubation with trypsin was omitted from the TAF extraction procedure, the resulting batches stimulated cell growth both on plastic and on collagen . A synergistic interaction also occurred between these TAF-containing tumour extracts and platelet-released factors . This effect was always more marked when the cells were growing on collagen than when on plastic . These data suggest that the nature of the substratum affects the response of the endothelial cells to TAF and to platelet-released factors.

Cancer Res, 1979 Aug, 39(8), 3194 - 8
Toxicity of metabolic benzo(a)pyrenediones to cultured cells and the dependence upon molecular oxygen; Lorentzen RJ et al.; The three quinone metabolites of carcinogenic benzo(a)pyrene, the isomeric benzo(a)pyrenediones (6, 12; 1,6; 3,6), are toxic to cultured hamster cells at low concentrations . The reduction in cell number, observed after treatment with these metabolites, is the result of both direct cell killing and the inhibition of growth, since DNA synthesis is inhibited very early after treatment with benzo(a)pyrene 1,6-dione when little cell death has occurred . The rate of RNA synthesis was also inhibited by treatment of cells with benzo(a)pyrene 3,6-dione . These actions of the benzo(a)pyrenediones toward hamster cells can be eliminated or substantially reduced by the removal of oxygen from the growth medium and atmosphere in which the cells are incubated . In contrast, anaerobic conditions do not reduce the cytotoxicity observed with the alkylating agent ethyl methanesulfonate . These results support the hypothesis that benzo(a)pyrenediones, and other biologically active quinones, owe their activity to oxidation-reduction cycles involving quinone, hydroquinone, and molecular oxygen; the reactive reduced oxygen radicals and semiquinone radical formed during these cycles may be responsible for the observed cellular injury and inhibition of cellular processes.

Mutat Res, 1979 Aug, 62(1), 35 - 42
Antagonism by propidium of petite induction by ethidium and ethidium azide in Saccharomyces cerevisiae; Fukunaga M et al.; Propidium, a phenanthridinium dye similar to ethidium, did not induce petite mutations in non-growing yeast cells in contrast to ethidium . Combined exposure to ethidium and an excess of propidium for periods up to 2 h resulted in the expected petite induction expressed after subsequent plating on growth medium . As incubation was continued with propidium, the numbers of petites declined on subsequent plating whether the drug had been added before, during, or after the mutagenic treatment by ethidium . Propidium decreased petite induction by the monoazide analog of ethidium when applied before but not after photolytic attachment of the drug.

Proc Natl Acad Sci U S A, 1979 Aug, 76(8), 3670 - 2
Adenine aminohydrolase: occurrence and possible significance in trypanosomid flagellates; Kidder GW et al.; Adenine aminohydrolase (EC 3.5.4.2) from four species of Leishmania and from Crithidia fasciculata was examined for specific activities, affinity for substrate (adenine), and stability to heat . All were found to be strongly and non-competitively inhibited by both coformycin and deoxycoformycin, two tight-binding inhibitors of adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) . Deoxycoformycin is the more potent inhibitor of the two . Neither inhibitor was active against the purine phosphoribosyltransferases . When deoxycoformycin was added to the defined growth medium containing hypoxanthine as the purine source, the growth of C . fasciculata was unaffected, but when adenine was the purine source for the organism, severe inhibition resulted . This implies that hypoxanthine is the obligatory base for nucleotide synthesis and that the adenine phosphoribosyltransferase (AMP:pyrophosphate phosphoribosyltransferase, EC 2.4.2.7) is, in some manner,idenied access to exogenous substrate.

J Protozool, 1979 Aug, 26(3), 510 - 8
Secretion of hexosaminidase isozymes by Tetrahymena; Vick GW 3rd et al.; Tetrahymena pyriformis strain HSM secrete large quantities of lysosomal acid hydrolases into the medium . The finding that 2 isozymes of beta-N-acetylhexosaminidase (2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxyglucohydrolase; EC 3.2.1.30) could be resolved by DEAE ion exchange chromatography and of possible differences between the secreted mixture and the intralysosomal hexosaminidase activity suggested that Tetrahymena might prove useful for studies of the control of lysosomal hydrolase isozyme secretion . In the present paper, we report a considerable purification of these isozymes and describe a number of their kinetic properties . Four isozymes were isolated into 2 major forms, A1 and B1, and 2 minor forms, A2 and B2, which were similar to the respective major forms in all kinetic properties tested . Hexosaminidase B1 has a molecular weight of approximately 93,000 daltons and is inhibited by high concentrations of p-nitrophenyl-N-acetyl-beta-D-glucosaminide . The inhibition is reversed by ethanol . Hexosaminidase B1 has a molecular weight of approximately 93,000 daltons and is inhibited by high concentrations of p-nitrophenyl-N-acetyl-beta-D-glucosaminide . The inhibition is reversed by ethanol . Hexosaminidase A1 has a molecular weight of approximately 170,000 and is not inhibited by high concentrations of substrate . The A forms are relatively less active against p-nitrophenyl-N-acetyl-beta-D-galactosaminide than the B forms . Neither hexosaminidases A1 or B1 has any endo-beta-N-acetylhexosaminidase activity . Comparison of the properties of the 2 major isozymes suggested that measurements of activity obtained under different assay conditions could be used to quantitate the amount of each isozyme in a mixture of the two . Log- and early stationary-phase cells secrete approximately 20% of isozyme A and 80% of isozyme B into the medium or into a dilute salt solution . With increasing culture age the fraction of isozyme A secreted rises to over 90% . Supplementation of the proteose-peptone growth medium with glucose causes a decrease in total hexosaminidase subsequently secreted but with no change in proportion of each isozyme . Cells suspended in a dilute salt solution containing 0.1 mM L-propranolol secrete slightly more isozyme A than do control cells suspended without L-propranolol . Phenoxybenzamine (0.2 mM) causes a slight decrease in the proportion of isozyme A released.

Biochim Biophys Acta, 1979 Jul 27, 574(1), 39 - 47
Plasma membrane lipids of human diploid fibroblasts from normal individuals and patients with cystic fibrosis; Riordan JR et al.; The lipid composition of isolated plasma membranes of human skin fibroblasts is described for the first time . Plasma membranes from a number of strains of fibroblasts from patients with cystic fibrosis and matched normals were isolated by a recently described procedure and analysed for major phospholipid classes, cholesterol and fatty acids . No differences in the quantities of these compounds were detected between cells of the two different origins . The fetal calf serum used to supplement the growth medium contained relatively more palmitoleate and oleate but less stearate than the membranes . There were also no consistent differences between cystic fibrosis and normal membranes in terms of the fatty acid compositions of their individual phospholipid classes . Consistent with this lack of chemical change in the lipids of membranes of cystic fibrosis cells, the degree of fluorescence polarization of diphenylhexatriene, an index of fluidity, was also unchanged.

Mol Gen Genet, 1979 Jul 2, 174(1), 33 - 8
Regulation of s-amino acids biosynthesis in Saccharomycopsis lipolytica; Morzycka E et al.; ATP-sulfurylase, cysteine synthase, homocysteine synthase, arylsulfatase and beta-cystathionase in Saccharomycopsis lipolytica are repressed on the addition of methionine, homocysteine or cysteine to the growth medium . The use of appropriate mutants enabled us to demonstrate that the synthesis of these enzymes is regulated by the system involving at least two low-molecular weight effectors--most likely cysteine and methionine (or their close derivatives).

Mikrobiologiia, 1979 Jul-Aug, 48(4), 738 - 44
{Microbial cenosis in the initial stage of spruce needle decomposition}; Zaitsev SA et al.; The formation of saprophytic microbial cenosis at the primary stage of decomposition of spruce needles was studied by the method of scanning electron microscopy with parallel inoculations into growth media . The composition of the cenosis was found to differ depending on whether the needles were decomposed on the surface of the forest floor or on the soil without any flooring . The characteristics of the formation of the saprophytic microbial cenosis are described . The cenosis is formed from individual species of the soil microbial complex and from some representatives of the epiphytic microbial cenosis which change here becoming saprophytes instead of biotrophs . Yeasts and yeast-like organisms predominate at the primary stage of decomposition of spruce needles.

J Natl Cancer Inst, 1979 Jul, 63(1), 29 - 41
Growth of normal and malignant human mammary epithelial cells in culture; Kirkland WL et al.; Normal and malignant human mammary epithelial cells were placed in culture . Normal cells were recovered from late-lactation milk and breast fluids, and malignant cells were isolated from primary breast tumors by collagenase digestion . The concentration of cells obtained from breast fluid samples was inversely proportional to the volume of fluid secreted . Most of these cells adhered rapidly to the substrate, did not replicate, displayed Fc receptor-dependent phagocytic activity, and were thus identified as macrophages . The remaining cells grew out into large islands comprised of one or two distinct morphologic types of mammary epithelial cells . Optimum growth of these cells was obtained in medium buffered to pH 6.8, and the epidermal growth factor markedly prolonged the exponential growth phase of the cells . Two morphologically distinct populations of epithelial cells were also observed in cultures established from individual breast tumors . Growth of the malignant cells was relatively unaffected by the pH of the culture medium, and the cells were unresponsive to exogenously added hormones . Overgrowth of malignant epithelial cells in primary cultures by stromal fibroblasts was retarded by replacement of standard growth medium with fresh medium containing a serum substitute; growth of the malignant epithelial cells was unaffected . A feeder layer of mitomycin C-treated human fibroblasts increased the plating efficiency of both normal and malignant cells in primary culture and also facilitated passage of these cells to secondary and tertiary cultures.

Biull Eksp Biol Med, 1979 Jul, 88(7), 76 - 8
{Synthesis of alpha-fetoprotein, albumin and transferrin by long-term cultured cells of murine hepatoma}; Aleksanian IuT; The capacity of continuous cell of XXIIa mouse hepatoma (strain MHXXIIa) to synthesize alpha-fetoprotein, albumin and transferrin was studied by immunoautoradiography . Albumin and transferrin were detected in the polyethylene glycol concentrated growth medium of hepatoma cells on the 5th year (the 55th month) of their cultivation . alpha-fetoprotein was not found . Only transferrin was revealed in the growth medium of hepa toma cells of the 8th year (the 92d month) of cultivation . Two clonal cultures obtained on the 8th year of hepatoma cell cultivation were also characterized by the ability to synthesize transferrin . The continuous mouse hepatoma cells retained their malignancy . The agar micro-precipitation reaction showed the presence of alpha-fetofetoprotein in lyfogel concentrated serum of mice with tumors formed after inoculation of the hepatoma cells of the 5th year of cultivation . However, alpha-fetoprotein was not detected in the serum of mice with tumors induced by inoculation of the hepatoma cells of the 8th year of cultivation.

Mikrobiologiia, 1979 Jul-Aug, 48(4), 711 - 5
{Candida mycoderma growth inhibition with phenol and the autoselection of resistent forms under continuous pH-stat cultivation}; Bril'kov AV et al.; The effect of phenol on the growth rate and respiration was studied with the yeast Candida mycoderma cultivated in the pH-static conditions with continuous recording of the principal kinetic parameters of the population . The kinetics of growth inhibition with phenol was studied . Adaptation of the culture in terms of the growth rate and the rate of oxygen uptake was detected within 10--15 hours of cultivation . A new strain of C . mycoderma Phen . R . isolated using the technique of autoselection upon continuous cultivation for a long period of time, at a phenol concentration of 1.5 g/l in the growth medium, had an elevated growth rate (2.2 times higher) in these conditions as compared with the parent culture and required less oxygen.

Biochim Biophys Acta, 1979 Jun 13, 554(1), 156 - 67
Active K+ transport in Mycoplasma mycoides var . Capri . Net and unidirectional K+ movements; Leblanc G et al.; Analysis of the cation composition of growing Mycoplasma mycoides var . Capri indicates that these organisms have a high intracellular K+ concentration (Ki: 200--300 mM) which greatly exceeds that of the growth medium, and a low Na+ concentration (Na+i: 20 mM) . Unlike Na+i,K+i varies with cell aging . The K+ transport properties studied in washed organisms resuspended in buffered saline solution show that cells maintain a steady and large K+ concentration gradient across their membrane at the expense of metabolic energy mainly derived from glycolysis . In starved cells, K+i decreases and is partially compensated by a gain in Na+ . This substitution completely reverses when metabolic substrate is added (K+ reaccumulation process) . Kinetic analysis of K+ movement in cells with steady K+ level shows that most of K+ influx is mediated by an autologous K+-K+ exchange mechanism . On the other hand, during K+ reaccumulation by K+-depleted cells, a different mechanism (a K+ uptake mechanism) with higher transport capacity and affinity drives the net K+ influx . Both mechanisms are energy-dependent . Ouabain and anoxia have no effect on K+ transport mechanisms; in contrast, both processes are completely blocked by dicyclohexylcarbodiimide, an inhibitor of the Mg2+ -dependent ATPase activity.

Biochim Biophys Acta, 1979 Jun 12, 585(2), 210 - 9
Epoxide hydrase in Trypanosoma cruzi epimastigotes; Yawetz A et al.; 1 . Microsomal fractions from Trypanosoma cruzi epimastigotes catalyze the hydration of styrene oxide to styrene glycol . The activity is linear up to 45 min of incubation, is proportional to microsomal protein concentration within certain range, and has an optimum pH of 8.5 . 2 . Double-reciprocal plots indicate a Km value of 5.3 . 10(-4) M for styrene oxide and a V of 29.6 pmol of styrene glycol formed/min per mg protein at 37 degrees C . 4-Chlorophenyl-2,3-epoxypropyl either (Ki = 2.08 . 10(-4) M) and juvenile hormone I (Ki = 2.7 . 10(-4) M) are competitive inhibitors; whereas, 1-chloro-2,3-epoxypropane is a non-competitive inhibitor . The enzyme is induced about three-fold by 5 mM phenobarbital in the growth medium . 3 . The epoxide hydrase is not activated by detergents but rather inhibited by concentrations of Tween-80 and Lubrol as low as 0.025% . 4 . Experiments with intact cells indicate that about 3% of {8-14C}styrene oxide penetrates after 90 min of incubation; whereas, over 30% of juvenile hormone I is found intracellularly after the same incubation period . Intracellular styrene oxide is hydrated to styrene glycol to a significant extent and the in vivo hydration is increased by pretreatment with phenobarbital and inhibited upon the addition of 4-chlorophenyl-2,3-epoxypropyl ether . Only a small amount of the intracellular juvenile hormone I is recovered as the corresponding diol ester.

Parasitology, 1979 Jun, 78(3), 343 - 54
The uptake in vitro of dyes, monosaccharides and amino acids by the filarial worm Brugia pahangi; Chen SN et al.; The uptake in vitro of various substances by Brugia pahangi was investigated using infective larvae obtained from Aedes aegypti and worms removed from Meriones unguiculatus at 2, 3, 10, 20 and 90 days post-infection . Worms incubated in growth medium 199 containing 1% Trypan blue possessed demonstrable dye in the oral orifice, the anterior oesophageal lumen and the external openings of the vulva and the cloaca or anus but the dye was not found in the gut lumen even after incubation for 24 h . No uptake of ferritin particles into the intestine of the worms was found and no fluorescence could be demonstrated in the gut lumen of worms incubated in medium containing 50% (v/v) fluorescein isothiocyanate-conjugated calf serum for up to 24 h . Trypan blue uptake by the gut of Aspiculuris tetraptera was clearly observed after incubation for several hours . The uptake of D-glucose and L-leucine by B . pahangi was demonstrated using autoradiographic and scintillation counting techniques and incorporation into worm tissues was detected . Glucose was found to be readily incorporated in the apical, glycogen-rich areas of the myocytes of worms of all ages studied and in the uterine epithelium of the adult female . In contrast, a lower incorporation of D-glucose was found in the eggs, embryos and vas deferens and especially in the gut . The incorporation of L-leucine occurred throughout the tissue of the worms during a 30 min incubation . Labelling was also located over the surface of the cuticle of the worms, when incubated for a period of 15 to 60 min in L-{H}leucine . Scintillation counting techniques demonstrated that there was no uptake of 14C-labelled L-glucose or sucrose by B . pahangi . The data presented on the uptake in vitro of nutrients or other compounds by infective larvae and adult stages of B . pahangi did not demonstrate an intestinal route of uptake but indicated that the transcuticular route of uptake may be employed.

J Gen Microbiol, 1979 Jun, 112(2), 389 - 92
The components of Mycoplasma salivarium and its growth medium that are responsible for film formation; Ichimaru H et al.; Studies on film production by mycoplasmas revealed that film was produced by completely disintegrated mycoplasma cells on Noble agar in the presence of horse serum . Film production was due to an enzymic reaction between mycoplasma lipase, possibly phospholipase A, and phospholipid in serum.

J Cell Physiol, 1979 Jun, 99(3), 319 - 26
Production of factors required for cell attachment and spreading is a constitutive property in mouse A9 cells; Dairkee SH et al.; It is demonstrated here that cells in a suspension culture of an established mammalian cell line release non-dialyzable factors into their growth medium . These factors are capable of promoting the adhesion and spreading of these cells on a generally non-attachable substratum and also promote spreading on an adhering substrate . Evidence is presented which demonstrates that the spreading promotion activity of the condition medium is dependent on the cell density of the culture from which it was derived . Dilution of the conditioned medium results in a proportionate dilution of the spreading promotion activity . The results clearly demonstrate that the production of this spreading promotion factor is continued even in the absence of cell to substrate attachment.

Biochim Biophys Acta, 1979 Jun 1, 585(1), 94 - 9
Transport of L-carnitine induced by prednisolone in an established cell line (CCL 27) . A possible explanation of the therapeutic effect of glucocorticoids in muscular carnitine deficiency syndrome; Molstad P et al.; Prednisolone (10(-8)--10(-5) mol/l) in the growth medium for 24 h increased the rate of uptake of L-{3H}carnitine in an established cell line (CCL 27) to 164 +/- 6% (mean +/-S.E.) of the rate observed in untreated cells . At the same time the intracellular content of free L-carnitine increased about 20% . The simultaneous addition of prednisolone (10(-6) mol/l for 24 h) and L-carnitine (10(-4) mol/l for 96 h) to the growth medium increased the rate of uptake to 225 +/- 8% (mean +/-S.E.) of that in untreated cells . The increase seemed to be mediated through an increase in number of carriers, as judged by the increase in V of the transport process with unchanged Km . Phosphodiesterase I, an enzyme mainly localized in the plasma membrane, increased its activity about 3.5 times when cells were stimulated with prednisolone . Thus, it seems that the increase in the rate of uptake of L-carnitine mediated by glucocorticoids, is part of a more general effect on the plasma membrane . The observations offer an explanation to the observed clinical improvement in patients with muscular carnitine deficiency treated with glucocorticoids and/or L-carnitine.

J Cell Physiol, 1979 Jun, 99(3), 303 - 12
Relationship between histidyl-tRNA level and protein synthesis rate in wild-type and mutant Chinese hamster ovary cells; Lofgren DJ et al.; A preliminary investigation was carried out to determine how conditional lethal mutants affected in particular aminoacyl-tRNA synthetases may be used to study the role of tRNA charging levels in protein synthesis . The relationship between rate of protein synthesis and level of histidyl-tRNA in wild-type cultured Chinese hamster ovary cells was determined using the analogue histidinol to inhibit histidyl-tRNA synthetase activity . This response was compared with that obtained using a mutant strain with a defective histidyl-tRNA synthetase that phenotypically shows decreased rates of protein synthesis at reduced concentrations of histidine in the growth medium . The approach used was based on measuring the histidyl-tRNA levels in live cells . The percentage charging was estimated by comparing {14C}histidine incorporated into alkali-labile material in paired samples, one of which was treated with cycloheximide, five minutes before terminating during the incubation, to produce maximal aminoacylation . Wild-type cells under histidinol inhibition exhibited a sensitive, sigmoidal relationship between the level of histidyl-tRNA and the rate of protein synthesis . A decrease in the relative percentage of acylated tRNA (His) from 46% to 35% elicited a large reduction in the rate of protein synthesis from 90% to 30% relative to untreated cells . An unpredicted result was that the relationship between protein synthesis and histidyl-tRNA in the mutant was essentially linear . High acylation values for tRNA (His) were associated with rates of protein synthesis that were not nearly as high as in wild-type cells . These findings suggest that the charging charging levels of tRNA (His) isoacceptors could play a regulatory role in determining the rate of protein synthesis under conditions of histidine starvation in normal cells . The mutant appears to be a potentially useful system for studying the pivotal role of tRNA charging in protein synthesis, assuming that the altered response in the mutant is caused by its altered synthetase.

J Cell Sci, 1979 Jun, 37, 157 - 67
A ligand-receptor model for the cohesive behaviour of Dictyostelium discoideum axenic cells; Jaffe AR et al.; Axenically grown cells of D . discoideum Ax-2 harvested in the log phase of growth, cohere rapidly when shaken in phosphate buffer . After 3.5 days in the stationary phase of growth, cells become completely non-cohesive . Although they do not stick to each other, stationary phase cells do stick to both log phase cells and aggregation-competent cells . The cohesion of stationary phase cells with these other 2 cell types is inhibited by both EDTA and the low-molecular-weight factor which we have previously demonstrated in stationary-phase growth medium . There is a decline in the sensitivity of slime mould cell cohesion to the low-molecular-weight inhibitory factor as the cells become aggregation-competent . This effect parallels the developmentally-regulated decline in sensitivity to EDTA . The low-molecular-weight inhibitor is not a chelating agent, however . The effect of the inhibitor seems to be specifically against contact sites-B mediated cohesion . We suggest that the simplest cohesive mechanism which can explain our results, is that the EDTA-sensitive cohesion of log phase cells could be dependent on a ligand-receptor system.

J Immunol, 1979 Jun, 122(6), 2516 - 20
In search of alpha 1-microglobulin on the lymphocyte surface; Akerstrom B et al.; alpha 1-Microglobulin was found by immunofluorescence not to be associated with human lymphoid and nonlymphoid cell lines . No accumulation of alpha 1-microglobulin was detected in culture media of these cell lines . A weak membrane fluorescence with anti-alpha 1-microglobulin on peripheral lymphocytes could not be blocked by the purified protein . No release of alpha 1-microglobulin into the growth medium was seen by normal cultured leukocytes . Treatment of normal lymphocytes, erythrocytes, and various cell lines with solubilization techniques did not yield any alpha 1-microglobulin . alpha 1-Microglobulin and protein HC display immunologic and biochemical identity . However, anti-protein HC stained almost all of the tested cell lines and normal lymphocytes . Blocking experiments with the purified protein were not successful . Antibodies reacting with a minor impurity (50,000 d) in the alpha 1-microglobulin or protein HC preparations could be absorbed from anti-alpha 1-microglobulin with normal leukocytes and a lymphoid cell line.

Mol Gen Genet, 1979 May 23, 173(1), 71 - 84
Chromosomal and extrachromosomal control of senescence in the ascomycete Podospora anserina; Tudzynski P et al.; In Podospora anserina senescence leading to cellular death occurs regularly after prolonged vegetative propagation . However, the life span of this ascomycete may be extended by various means: 1 . Mutations in a least 8 morphogenetic genes belonging to 4 linkage groups postpone drastically or even prevent in certain pairwise combinations (e.g . i viv) the onset of senescence . 2 . Inhibitors of mt DNA and of mitochondrial protein synthesis show a life prolonging effect when added in low concentrations to the growth medium . 3 . A similar effect was found when mycelia were fed exclusively on non repressive carbon sources . Whereas the anti-aging effect of specific mutated genes is rather permanent, the life prolonging action of the inhibitors and carbon sources is restricted and temporary . These substances have no long lasting effect, since after their removal from the medium aging proceeds . Physiological experiments have further shown the existence of three phases in the life span of Podospora anserina . During the juvenile phase aging is prevented by all of these compounds; during the presenescent phase aging is prevented by inhibitors of mt DNA only, and during the senescent phase aging is irreversible . Senescence may be induced in juvenile protoplasts by DNA extracted from senescent mycelia . This, together with the well known fact that senescence is extrachromosomically inherited, points to extrachromosomal DNA as the causative agent of senescence . This kind of DNA may be connected with or perhaps located in the mitochondria . Collectively, the data are consistent in showing that the syndrome of senescence in Podospora anserina is controlled by a chromosomal-extrachromosomal interaction . In this system, extrachromosomal DNA, perhaps a mt DNA, is identical with the infectious principle initiating the decay of the cell, and nuclear genes supervise its expression.

J Gen Microbiol, 1979 May, 112(1), 15 - 27
Characteristics of a lipolytic and fatty acid-requiring Butyrivibrio sp . isolated from the ovine rumen; Hazlewood G et al.; A naturally occurring fatty acid-requiring Butyrivibrio sp . (strain S2), isolated from the ovine rumen, deacylates plant galactolipids, phospholipids and sulpholipids to obtain sufficient fatty acid for growth . Growth in vitro was promoted by adding to the growth medium a single straight-chain saturated fatty acid (C13 to C18) or vaccenic acid . Palmitoleic and oleic acids also supported growth but gave lengthy lag phases probably due to their toxicity . Linolenic and linoleic acids supported good growth but they were completely hydrogenated to trans-11-octadecenoic acid which was incorporated into the bacterial complex lipids . No chain elongation, chain shortening or desaturation of the added fatty acids occurred and all were substantially incorporated into bacterial lipids of the plasmalogen type, partially as a new type of hydrophobic grouping derived from two molecules of fatty acid . The absence of fatty acid unsaturation poses the question of the maintenance of membrane fluidity within this bacterium.

Mikrobiologiia, 1979 May-Jun, 48(3), 400 - 5
{Efficiency of glucose utilization by Gluconobacter oxydans}; Uspenskaia SN et al.; The dynamics of growth and acid production in Gluconobacter oxydans cultures at various glucose concentrations has been investigated . Dinitrophenol (10-4 M) was shown to have effect on hexonic acids formation by the growing culture and resting cells of G . oxydans, as well as on the values of Y0 . G . oxydans molar growth yield for glucose have been calculated . Oxidative transformation of glucose was shown to be not involved in energy supply of processes connected with the reproduction of G . oxydans . Glucose concentration in the growth medium determines the efficiency of utilization of this carbon and energy source.

J Cell Physiol, 1979 May, 99(2), 239 - 46
Selection and characterization of a varient of murine L5178Y lymphoma resistant to local anesthetics; Yau TM et al.; A varient of murine L5178Y lymphoma resistant to procaine hydrochloride (PH) was selected by exposing the cells to gradual increments of PH in the growth medium until the cell grew exponentially in the presence of 1.5 mM PH . Using cinephotomicrography, it was observed that the majority of cells that initially succumbed to PH failed to undergo successful mitosis . With respect ot chromosomal, cell size distribution and flow microfluorometric analyses, the PH-resistant cells are very similar to a spontaneous tetraploid cell line (R1T) previously cloned . The isolated cells, designated R1/P, were also found to be cross-resistant to analogues of PH, namely, lidocaine, tetracaine and dibucaine . The naturally-occurring tetraploid cell line (R1T) was also found to be more resistant to local anesthetics, although not to the same extent as R1/P cells . Since the enzyme that hydrolyzes procaine appears to be absent in all these lymphoid cell lines, the difference in resistance does not appear to depend on differences in the ability of these cells to remove the agent . It is suggested that an alteration in the structure and/or function of the plasma membrane in R1/P cells have rendered them either less sensitive to the membrane-perturbing effects of the local anesthetics or less permeable to local anesthetics molecules . The ability of local anesthetics to affect membranes and cytoskeleton structures may play a role in the genesis and/or selection of these cell variants.

Prikl Biokhim Mikrobiol, 1979 May-Jun, 15(3), 475 - 7
{Effect of a deficiency of carbon, nitrogen, phosphorus and magnesium in the growth medium on the mechanical properties of Escherichia coli cell walls}; Chemeris NA et al.; Values of modulus of elasticity of cell walls and strength level of cells Escherichia coli cultivated in the carbon, nitrogen and phosphorus deficient media or incubated in the magnesium-free medium were determined . Elastic modulus of cells grown in the magnesium-free medium was by two order of magnitude lower than that of the control cells . Elastic modulus of cells cultivated in the nitrogen and carbon deficient media was by one and two orders of magnitude lower than in the control cells whereas strength level was by 1.15 and 1.39 times higher, respectively . Elastic modulus of cells grown in the phosphorus deficient medium remained undetermined and strength level of those cells proved to be the lowest (0.9 of the control).

J Med Chem, 1979 May, 22(5), 592 - 4
Synthesis and biological activity of 5-fluoro- and 5-methyl-1,3-oxazine-2,6(3H)-dione; Bobek M et al.; 5-Fluoro-1,3-oxazine-2,6(3H)-dione (3-oxa-FU) was synthesized by reacting 3-oxauracil with fluoroxytrifluoromethane and decomposing the adduct in the presence of a catalytic amount of Et3N . 5-Methyl-1,3-oxazine-2,6(3H)-dione (3-oxathymine) was prepared by polyphosphoric acid catalyzed ring closure of beta-(N-ethoxycarbonylamino)-2-methacrylic acid and by treatment of citraconimide with sodium hypochlorite . As determined in vitro, 3-oxa-FU was markedly inhibitory to S . faecium (ID50 = 9 X 10(-8) M) and E . coli (ID50 = 1 X 10(-7) M) but was less active against leukemia L-1210 cells (ID50 = 1 X 10(-5) M) . At 1 x 10(-4) M, 3-oxathymine was inactive in these cell systems . Inhibition of the growth of S . faecium by 3-oxa-FU was reversed competitively by the natural pyrimidines . The relatively rapid hydrolysis of the compounds in the growth media is a major factor in determining their biological effectiveness.

J Bacteriol, 1979 May, 138(2), 492 - 8
Protein and ribonucleic acid syntheses in heat-damaged and heat-killed Escherichia coli; Dean RG et al.; Protein and ribonucleic acid (RNA) syntheses were measured in both lethally injured and thermally damaged viable cells after heating at lethal temperatures . Immediately after heating, cells were incubated in growth media containing either {14C}leucine or {3H}uracil . The labeled cells were subsequently treated with penicillin . Viable cells were shown to lyse, and the intact nonviable cells were collected by centrifugation . The results showed that after heating, protein and RNA synthesis were reinitiated in the penicillin-sensitive cell population, but there was no detectable protein or RNA synthesis in the heat-killed cells which were resistant to penicillin . The lack of protein or RNA synthesis in lethally damaged cells during the entire recovery period may be interpreted to reflect the lethal thermal damage.

J Biochem (Tokyo), 1979 May, 85(5), 1367 - 75
Comparison of inducible and constitutive kynureninases of Neurospora crassa; Tanizawa K et al.; Two types of kynureninase were isolated from Neurospora crassa IFO 6068 . The formation of one of them, which was separated from the inducible kynureninase by DEAE-cellulose chromatography, was independent of the presence of tryptophan in the growth medium . Ouchterlony double-diffusion analysis and immunochemical titration indicated that the constitutive-type enzyme is immunologically different from the inducible enzyme . We confirmed by a selective assay method with antiserum that the addition of tryptophan to the medium does not affect the formation of one of the enzymes (constitutive-type) . The constitutive kynureninase was purified approximately 650-fold and was free of the inducible enzyme as judged by analytical gel electrophoresis . The molecular weight and optimum pH values of both enzymes are very similar . However, the constitutive enzyme shows much higher activity and affinity for L-3-hydroxykynurenine than for L-kynurenine, suggesting that the enzyme functions biosynthetically as a 3-hydroxykynureninase . Constitutive kynureninase activities were widely found in all the fungi tested, whereas the inducible enzyme activity was not present in Mucor or Rhizopus species . The inducible enzymes of all the Neurospora strains examined were shown to be immunologically identical.

Eur J Biochem, 1979 Apr 2, 95(2), 287 - 93
Demonstration by membrane reconstitution of a butanol-soluble intermediate in the biosynthesis of the O9 antigen of Escherichia coli; Kanegasaki S et al.; The activity in vitro of the mannan-synthesizing system of Escherichia coli O9 depends on the presence of glucose in the growth medium of the bacteria . Inactive membranes of E . coli strain F988 grown without gain mannan-synthesizing activity by reconstitution with a butanol extract obtained from the same bacteria grown with glucose . Inactive membranes could also be restored to biosynthetic activity by incubation with UDP-glucose in the presence of magnesium chloride . In this magnesium-ion-dependent reaction, a glucolipid was formed which was extractable with butanol . It could be used for the reconstitution of inactive membranes . The products of incubations with GDP-mannose of reconstituted and active membranes were analysed for electrophoretic mobility in sodium dodecylsulfate/polyacrylamide gel electrophoresis, molecular weight and composition . In all cases they proved to be the mannan attached to a hydrophobic mannose carrier, presumably a glucolipid . These results suggest that a glucolipid is the intermediary mannose acceptor in the biosynthesis of the O9 antigen.

Appl Environ Microbiol, 1979 Apr, 37(4), 670 - 5
Effect of inorganic sulfide on the growth and metabolism of Methanosarcina barkeri strain DM; Mountfort DO et al.; Minimal growth of Methanosarcina barkeri strain DM occurred when sulfide was omitted fromthe growth medium, and addition of either sodium sulfate or coenzyme M to sulfide-depleted media failed to restore growth . Optimal growth occurred in the presence of 1.25 mM added sulfide, giving a molar growth yield (YCH4) of 4.4 mg (dry weight) of cells per mmol of CH4 produced . Increasing sulfide to 12.5 mM led to decrease in YCH4 (1.9 mg {dry weight}/mmol of CH4), in the specific growth rate and in be intracellular levels of adenosine triphosphate . However, the specific rate of methane production increased . The data suggested that at elevated sulfide levels (12.5 mM) the decrease in YCH4 might be a result of an increase in the relative energy needed for maintnenace and of uncoupling of growth from energy production.

J Cell Biol, 1979 Apr, 81(1), 1 - 9
On the mechanism of 5-bromodeoxyuridine induction of prolactin synthesis in rat pituitary tumor cells; Biswas DK et al.; GH12C1, a clonal strain of rat pituitary tumor cells in culture (GH cells), does not produce detectable amounts of prolactin . 5-Bromodeoxyuridine (BrdUrd), the thymidine analogue, at sublethal concentrations (3-5 microgram/ml) induces prolactin synthesis in these cells . BrdUrd also induces prolactin synthesis in F1BGH12C1 cells, a BrdUrd resistant (BrdUrdr) substrain isolated from GH12C1 cells . The F1BGH12C1 strain is not drug dependent, but its resistance to BrdUrd is a stable phenotype . The significant features of the induction of prolactin synthesis in the BrdUrdr strain are the increased net synthesis of prolactin and the shortening of the lag period of prolactin induction . As BrdUrd concentration in the growth medium is increased, the rise in prolactin synthesis parallels the increased incorporation of BrdUrd into DNA . Prolactin synthesis is first detected when BrdUrd replaces 20-25% of the thymidine in DNA . BrdUrd can replace up to 75-80% of the thymidine within 2 d of treatment . Partial starvation of these cells under specified growth conditions does not affect the general growth pattern of the cells, general protein synthesis, and thymidine uptake, but does affect DNA synthesis . When cells are cultured under conditions in which DNA synthesis is preferentially inhibited, BrdUrd does not induce prolactin synthesis, suggestive of a DNA-mediated mechanism of action for the drug.

Mol Cell Endocrinol, 1979 Apr, 14(1), 81 - 97
Prolactin receptors in primary cultures of carcinogen-induced rat-mammary tumors; Costlow ME et al.; 7,12-Dimethylbenz{alpha}anthracene-induced rat mammary tumors were dissociated with collagenase and hyaluronidase and placed into primary culture . In most cultures, specific binding of 125I-labeled ovine prolactin was (i) lower than that for the original tumors unless bovine prolactin (1 microgram/ml) had been added to the dissociation medium, and (ii) varied with the type of growth medium used . The level of prolactin binding in cultured cells was relatively constant for the first 7-10 days . Prolactin binding in cultured cell homogenates was maximal at pH 7.0, proportional to cell protein, specific for prolactin, and reached a steady state by 12 h at 22 degrees C . The half-maximum inhibition of 125I-labeled prolactin binding by unlabeled prolactin was 100 ng/ml for cells grown in 5-1000 ng of prolactin/ml . After prolactin was removed from the growth medium, the level of available binding sites progressively increased, reached a maximum at 48 h and then declined . At 48 h, the dissociation constant for prolactin binding (Kd approximately 1 x 10(-10) M) was comparable to that in tumors . In some cultured tumors, a 48-h treatment with 0.5 or 1.0 ng of prolactin/ml caused an apparent increase in the level of prolactin binding . Prolactin increased DNA synthesis and its removal caused a reduction in {3H}estradiol and {3H}-R5020 binding to cultured cell cytosols.

Cancer Treat Rep, 1979 Apr, 63(4), 587 - 90
In vitro growth of cutaneous T-cell lymphomas; Gazdar AF et al.; It is relatively easy to propagate EB virus-transformed normal and malignant B lymphocytes in vitro . Normal T lymphocytes divide for short periods of time after exposure to many mitogens . Exposure of normal T lymphocytes to lymphocyte-conditioned medium (LCM) permits them to divide for longer periods of time, but permanent cell lines cannot be established . Intial attempts to grow malignant T cells from patients with cutaneous T-cell lymphomas (CTCL) in unsupplemented growth medium resulted in the establishment of four EB virus-transformed B-lymphoblastoid lines . The responses of CTCL cells to mitogens and LCM varied from unresponsive to near normal . Subsequent attempts to grow CTCL cells in medium supplemented with mitogens or LCM resulted in the establishment of two cell lines lacking B-cell markers or EB virus . The cells of both lines initially had the ability to form E rosettes, although one of the lines has lost this ability with passage . The two lines can be distinguished from normal T cells by having some or all of the following properties: long-term proliferation, tumorigenecity in nude mice, gradual loss of dependence on mitogen or LCM, and convoluted nuclear morphology.

Cell, 1979 Apr, 16(4), 885 - 93
Transformed mammalian cells secrete specific proteins and phosphoproteins; Senger DR et al.; We have examined the proteins secreted into the growth medium by normal and transformed cells . Transformed cell lines from several mammalian species all secrete proteins in the 58,000 dalton molecular weight range . These proteins are all immunologically related and are secreted at low levels or not at all by the parental normal cell lines . Secretion of the 58K proteins occurs with either DNA or RNA virus transformation and with spontaneous transformation . The transformed cells also secrete phosphoproteins in the same size range, but these are immunologically distinct from the 58K proteins mentioned above . The sizes of the phosphoproteins are species-specific and unrelated to the transforming virus . Incubation of conditioned media from transformed cell cultures with gamma-32P-ATP labels phosphoproteins of the same sizes, indicating the presence in the media of both protein kinase and substrate . All three properties (58K protein, phosphoprotein, in vitro phosphorylation) are closely correlated with transformation in cells transformed by temperature-sensitive viruses . The biological implications of these results remain unknown, but the results may be relevant to recent data on the (phospho)proteins and protein kinase encoded by RNA tumor viruses and the molecular basis of the transformed phenotype.

Biochim Biophys Acta, 1979 Mar 28, 562(1), 162 - 76
Regulation of purine de novo synthesis in cultured human fibroblasts: the role of P-ribose-PP; Gordon RB et al.; Procedures for assaying the rate of purine de novo synthesis in cultured fibroblast cells have been compared . These were (i) the incorporation of {(14)C}-glycine or {(14)C}formate in alpha-N-formylglycinamide ribonucleotide (an intermediate in the purine synthetic pathway) and (ii) the incorporation of {(14)C}-formate into newly synthesised cellular purines and purines excreted by the cell into the medium . Fibroblast cells, derived from patients with a deficiency of hypoxanthine phosphoribosyltransferase (HPRT-) (EC 2.4.2.8) and increased rates of purine de novo synthesis, were compared with fibroblasts from healthy subjects (HPRT+) . Fetal calf serum, which was used to supplement the assay and cell growth medium, was found to contain sufficient quantities of the purine base hypoxanthine to inhibit purine de novo synthesis in HPRT+ cells . This inhibition was the basis of differentiation between HPRT- and HPRT+ cells . In the absence of added purine base, both cell types had similar capacities for purine de novo synthesis . This result contrasts with the increased rates of purine de novo synthesis reported for a number of human HPRT- cells in culture but conforms recent studies made on human HPRT- lymphoblast cells . The intracellular concentration and utilisation of 5-phosphoribosyl-1-pyrophosphate (P-Rib-PP), a substrate and potential controlling factor for purine de novo synthesis, were determined in HPRT- and HPRT+ cells . The rate of utilisation of P-Rib-PP in the salvage of free purine bases was far greater than that in purine de novo synthesis . Although HPRT- cells had a 3-fold increase in P-Rib-PP content, the rate of P-Rib-PP generation was similar to HPRT+ cells . Thus, in fibroblasts, the concentration of P-Rib-PP appears to be critical in the control of de novo purine synthesis and its preferential utilisation in the HPRT reaction limits its availability for purine de novo synthesis . In vivo, HPRT+ cells, in contrast to HPRT- cells, may be operating purine de novo synthesis at a reduced rate because of their ability to reutilise hypoxanthine.

J Biol Chem, 1979 Mar 25, 254(6), 1944 - 50
Regulation of hydroxydocosanoic acid sophoroside production in Candida bogoriensis by the levels of glucose and yeast extract in the growth medium; Cutler AJ et al.; Cells of Candida bogoriensis produce as a major extracellular lipid 13-{(2'-O-beta-D-glucopyranosyl-beta-D-glucopyranosyl)oxy}docosanoic acid 6',6''-diacetate (Ac2Glc2HDA), the diacetylated sophoroside of 13-hydroxydocosanoic acid (HDA), along with mono- and unacetylated derivatives . The HDA glycolipid production is greater than 2 g/liter when cells are grown on a "standard" medium of 3% glucose and 0.15% yeast extract . Either lowering the glucose concentration (0.5 to 2.0% glucose, at 0.2% yeast extract) or raising the yeast extract concentration (2 to 4% yeast extract at 3% glucose) greatly decreased the yield of this glycolipid, as well as its rate of synthesis measured by {14C}acetate incorporation . Total HDA production was also depressed on the low glucose medium, as was the activity of UDP-glucose:HDA glucosyltransferase, the first enzyme involved in the synthesis of Ac2Glc2HDA from HDA . Levels of acetyl-CoA:Glc2HDA acetyltransferase were not decreased by growth on a low glucose medium, however, even under conditions in which glycolipid production was less than 4% of that found in the standard medium . Low levels of the HDA glycolipids were monitored by high pressure liquid chromatography of their p-bromophenacyl esters, formed by the action of alpha,beta-dibromoacetophenone on the sodium salt of the lipid in the presence of a crown reagent catalyst . This regulation of extracellular Ac2Glc2HDA production by the nutrient composition of the growth medium may represent an important property in the adaptation of C . bogoriensis to its natural environment, the phyllosphere.

Biochim Biophys Acta, 1979 Mar 22, 583(3), 394 - 402
Inhibition of cell-substratum attachment of cultured rat heart cells by protein synthesis inhibitors; Speicher DW et al.; Addition of cycloheximide to growth medium of neonatal rat heart cell cultures prevented cell-substratum attachment . Even concentrations of cycloheximide which inhibited only 50% of normal protein synthesis prevented some cells from attaching . Cells which required the longest time to attach were not dependent on protein synthesis . The kinetics of cell-substratum adhesion in the presence of various concentrations of cycloheximide supported the hypothesis that repair of damaged cell membranes was required prior to attachment . An alternate hypothesis that protein synthesis was required for substratum attachment either to synthesize new unique proteins or higher concentrations of existing proteins not damaged by enzymes was not supported by experimentally obtained data . If the second hypothesis were true, no cells would have attached when protein synthesis was completely inhibited (greater than 95%) and all cells should have been equally affected by protein synthesis inhibition; such was not the case . Inhibition of mRNA formation by actinomycin D also should have inhibited attachment completely and this was not observed . Since attachment was minimally affected by actinomycin D, protein synthesis on long-lived mRNA was apparently sufficient for cell-substratum adhesion.

Mol Gen Genet, 1979 Mar 5, 170(3), 309 - 17
Relaxation of stable RNA synthesis by a plasmid-borne locus; Yarus M; The plasmid pMY3, which was constructed so as to express the Su+7 amber suppressor tRNA gene, also relaxes control of stable RNA synthesis in stringent cells . The relaxation is not growth medium or strain-dependent and does not occur in the presence of the vehicle alone . When expression of the effective sequence is diminished, in a lysogen of phi 80d3 ilv+Su+7, the sequence no longer affects RNA synthesis . The relaxation is general, extending to all or almost all tRNA loci, including tRNAs located in the ribosomal spacer regions, and to all ribosomal RNAs . Relaxed plasmid-carrying strains are still able to elevate guanosine tetra- and penta-phosphate levels in response to amino acid starvation, but steady state levels are somewhat diminished . Aminoacyl-tRNA falls to control levels when the plasmid-carrying strain is deprived of amino acid . Therefore, the relaxed strain perceives amino acid starvation, but does not respond normally . These properties define a novel locus which relaxes stringent control.

Am J Vet Res, 1979 Mar, 40(3), 387 - 92
Production of labile Newcastle disease virus progeny after infection of chicken embryo cells in the presence of caffeine; Olson NJ et al.; A study was undertaken to examine the effects of caffeine on Newcastle disease virus (NDV) infection of chicken embryo cells . Addition of 10 mM caffeine to the growth medium produced 95% reduction in progeny synthesis, 63% reduction in RNA synthesis, 45% reduction in protein synthesis, and 25% reduction in hemadsorption ability in NDV-infected cultures when compared with untreated, infected cultures . Purified NDV obtained from caffeine-treated, infected cultures was more sensitive to ultraviolet irradiation and to damage by freezing and thawing than was observed in untreated virus cultures . The SDS-polyacrylamide gel electrophoresis revealed that purified virions contained the same complement of polypeptides, but there was a significant variation in the quantities of several of the NDV polypeptides.

Cancer Res, 1979 Mar, 39(3), 1051 - 5
Comparative studies of glucose metabolism in HTC, RLC, MH1C1, and Reuber H35 rat hepatoma cells; Schamhart DH et al.; Carbohydrate metabolism by four rat hepatoma cell lines in culture, namely, Reuber H35, MH1C1, RLC, and HTC, has been investigated . Glucose utilization by H35 and MH1C1 cells is lower than that by RLC and HTC cells . The four cell lines also differ with respect to the accumulation of lactic acid in the growth medium; in particular, H35 cells show uptake of lactic acid, rather than accumulation in the medium . Specific activities of a number of enzymes involved in glycolysis, gluconeogenesis, pentose phosphate pathway, and glycogen formation were determined in the four cell lines . A direct relationship between the differences was found for the activities of some enzymes belonging to carbohydrate metabolism, namely, hexokinase, pyruvate kinase, aldolases A and B, glucose-6-phosphate dehydrogenase, and phosphogluconate dehydrogenase and the differences found for glucose utilization by the different cell lines.

Appl Environ Microbiol, 1979 Mar, 37(3), 471 - 9
Evidence for the subcellular localization and specificity of chlordane inhibition in the marine bacterium Aeromonas proteolytica; Nakas JP et al.; Sublethal levels (10 to 100 micrograms/ml) of the chlorinated insecticide chlordane (1,2,4,5,6,7,8,8-octachloro-3a,4,7,7a-tetrahydro-4,7-methanoindan) were introduced into the growth medium of the marine bacterium, Aeromonas proteolytica . Chlordane inhibited the synthesis of an extracellular endopeptidase by almost 40% but exhibited no such inhibition of the extracellular aminopeptidase also produced during the growth cycle . Studied with 14C-labeled chlordane demonstrated that the insecticide was not biologically degraded under the test conditions used and that up to 75% of the recoverable chlordane was cell associated within 48 h . Studied with uniformly labeled L{14C}valine and {2-14C}uracil established that neither the transport nor the incorporation of these protein and ribonucleic acid precursors was inhibited by chlordane . Separation of the membrane fractions using isopycnic centrifugation localized 14C-labeled chlordane in the cytoplasmic membrane . Also, chlordane inhibited the membrane-bound adenosine 5'-triphosphatase while the soluble (released) form of this enzyme remained unaffected . These data indicate that chlordane resides in the cytoplasmic membrane and may cause specific alterations in membrane-associated activities.

J Antibiot (Tokyo), 1979 Mar, 32(3), 205 - 11
Purification and partial characterization of an antibiotic produced by Myxococcus coralloides; Arias JM et al.; A strain of Myxococcus coralloides producing an antibiotic capable of inhibiting growth of Gram-positive bacteria was isolated . Antibiotic production occurred during vegetative growth but not during myxospore formation . The antibiotic was extracted from the growth medium with chloroform and purified by adsorption on silicic acid and by preparative silica gel thin-layer chromatography . The purified antibiotic showed a resistance to heat, acid, alkali and proteolytic enzymes . Chromatographic and electrophoretic behavior as well as infrared, ultraviolet and mass spectra are presented.

Biochim Biophys Acta, 1979 Feb 26, 572(2), 352 - 62
Mutant and immunochemical studies on the involvement of cytochrome b5 in fatty acid desaturation by yeast microsomes; Ohba M et al.; The involvement of cytochrome b5 in palmitoyl-CoA desaturation by yeast microsomes was studied by using yeast mutants requiring unsaturated fatty acids and an antibody to yeast cytochrome b5 . The mutants used were an unsaturated fatty acid auxotroph (strain E5) and a pleiotropic mutant (strain Ole 3) which requires either Tween 80 and ergosterol or delta-aminolevulinic acid for growth . Microsomes from the wild-type strain possessed both the desaturase activity and cytochrome b5, whereas those from mutant E5 contained the cytochrome but lacked the desaturase activity . Microsomes from mutant Ole 3 grown with Tween 80 plus ergosterol were devoid of both the desaturase activity and cytochrome b5, but those from delta-aminolevulinic acid-grown mutant Ole 3 contained cytochrome b5 and catalyzed the desaturation . The cytochrome b5 content in microsomes from mutant Ole 3 could be varied by changing the delta-aminolevulinic acid concentration in the growth medium, and the desaturase activity of the microsomes increased as their cytochrome b5 content was increased . The antibody to yeast cytochrome b5, but not the control gamma-globulin fraction, inhibited the NADH-cytochrome c reductase and NADH-dependent desaturase activities of the wild-type microsomes . It is concluded that cytochrome b5 is actually involved in the desaturase system of yeast microsomes . The lack of desaturase activity in mutant Ole 3 grown with Tween 80 plus ergosterol seems to be due to the absence of cytochrome b5 in microsomes, whereas the genetic lesion in mutant E5 appears to be located at ther terminal desaturase.

Biochim Biophys Acta, 1979 Feb 19, 583(1), 55 - 62
4-Hydroxybenzyl alcohol . A metabolite produced during the biosynthesis of thiamine in Escherichia coli; White RH; 4-Hydroxybenzyl alcohol was identified by gas chromatography-mass spectrometry as a metabolite of Escherichia coli when it is grown on a medium containing no thiamine or 4-methyl-5-beta-hydroxyethyl thiazole . 4-Hydroxybenzyl alcohol was found to be derived from L-tyrosine and the amount produced was found to be inhibited by the addition of thiamine to the growth medium . The amount of 4-hydroxybenzyl alcohol produced, as measured by isotopic dilution, was shown to be equivalent to the amount of thiamine formed . Based on these observations, it was concluded that 4-hydroxybenzyl alcohol is the cleavage product produced during the biosynthesis of the thiazole moiety of thiamine from tyrosine.

Appl Environ Microbiol, 1979 Feb, 37(2), 208 - 12
Convenient procedures for the biosynthesis, isolation, and isotope labeling of cytochalasins; Zabel RA et al.; Efforts to improve small-scale yields of useful cytochalasins by fermentation resulted in selection of an enriched aflatoxin medium which increased yields by fivefold over those reported in the literature . With Helminthosporium dematoideum and Zygosporium masonii in stationary culture for 3 weeks, cytochalasins B and D were obtained in quantities approaching 700 and 500 mg/liter, respectively . It appears that the critical component in this growth medium is factors associated with whole wheat . By using these procedures, coupled with improvements in isolation, supplementation with two radioactive phenylalanine species readily produced {14C}- or {3H}cytochalasin B . Oxidation of carrier-free radioactive cytochalasin B to cytochasasin A readily provided this labeled congener as well . The isotopic ocnversion of precursor to crystalline products that met analytical criteria ranged from 2 to 4% of the administered radioactivity.

J Bacteriol, 1979 Feb, 137(2), 1031 - 4
Effect of growth medium on the relative polypeptide composition of cellular outer membrane and released outer membrane material in Escherichia coli; Loeb MR et al.; When ratios of the major polypeptides of the outer membrane isolated from cells of Escherichia coli B grown in minimal medium containing either a single amino acid or several amino acids were compared, no difference was observed . However, the ratio of these polypeptides in outer membrane material released into the medium during logarithmic phase growth on these two media was markedly different.

Proc Natl Acad Sci U S A, 1979 Feb, 76(2), 833 - 6
Heme biosynthesis in Friend erythroleukemia cells: control by ferrochelatase; Rutherford T et al.; The activities of the enzymes of heme biosynthesis (except protoporphyrin oxidase) have been followed during the induction of Friend cells in culture . All the enzyme activities increased after induction with dimethyl sulfoxide . The activities of the intermediate enzymes were much higher than those of delta-aminolevulinate synthase {succinyl-CoA:glycine C-succinyltransferase (decarboxylating), EC 2.3.1.37}, the initial enzyme, or ferrochelatase (protoheme ferro-lyase, EC 4.99.1.1), the final enzyme of the pathway . Ferrochelatase activity was not detectable in the uninduced cell . delta-Aminolevulinate synthase activity increased during the first 24 hr of induction; porphobilinogen deaminase activity began to increase after 48 hr and ferrochelatase activity, after 72 hr . However, the induction of heme synthesis followed the same time course as that of ferrochelatase activity, not that of delta-aminolevulinate synthase activity . The cellular growth medium was found to contain traces of protoporphyrins . Thus, ferrochelatase is shown to be rate limiting for heme synthesis during early stages of Friend cell induction . A Friend cell variant (Fw), which is not inducible except in the presence of exogenous hemin, was also studied . All the enzymes of heme synthesis except ferrochelatase were inducible by butyric acid . Ferrochelatase was not inducible by butyric acid or hemin plus butyric acid . These cells also excrete protoporphyrin, The failure to induce ferrochelatase activity is believed to be the cause of, not a consequence of, the noninducibility of this cell line.

J Gen Virol, 1979 Feb, 42(2), 265 - 78
Stimulation of ornithine decarboxylase by human cytomegalovirus; Isom HC; Human cytomegalovirus (HCMV) infection of low serum-arrested confluent whole human embryo (Flow 5000) cells markedly stimulated ornithine decarboxylase (ODC) activity . Increased ODC activity was apparent by 12 h post-infection . The capacity of HCMV to stimulate ODC was: (1) dependent upon multiplicity of infection; (2) eliminated when the virus was neutralized with specific antiserum; and (3) sensitive to ultraviolet irradiation . Virus-mediated induction, in contrast to high serum induction of ODC, was not subject to inhibition by polyamines added to the growth medium . Phosphonoacetic acid (PAA) which blocks HCMV replication by inhibiting the activity of HCMV-specific DNA polymerase and which does not prevent HCMV induced stimulation of cell DNA synthesis, reversibly inhibited HCMV-induced stimulation of ODC activity by 74% . Studies with PAA indicated that HCMV-induced stimulation of ODC activity is independent of cell DNA synthesis and that the mechanism regulating virus-induced stimulation may be related to the HCMV-specific DNA polymerase.

J Cell Sci, 1979 Feb, 35, 307 - 20
On the reduced intercellular adhesiveness of virally transformed BHK21 cells; Edwards JG et al.; Baby hamster kidney fibroblasts (BHK21 cells) transformed by polyoma or Rous sarcoma viruses aggregate less than the untransformed parental cells when incubated in growth medium in a gyratory shaker for 18-24 h . This difference can be measured by electronic particle counting, or by filtering aggregated suspensions of 32P-labelled cells through bolting fabric . The aggregation of transformed derivatives is not enhanced by the presence, during aggregation of epsilon-amino caproic acid, an inhibitor of plasmin activation . Some lines of transformed BHK21 cells do not appear less adhesive than untransformed cells in a short-term aggregation assay, and none adheres markedly less well when seeded onto homotypic cell sheets . The decreased aggregation of transformed cells is consistent with suggestions that LETS protein is involved in intercellular adhesion of fibroblasts as well as in attachment of cells to non-cellular substrates . If so, the short-term aggregation of freshly trypsinized cells may depend on secretion of LETS from an intracellular pool.

Eur J Clin Invest, 1979 Feb, 9(1), 5 - 10
The effects of albumin bound fatty acids on the platelet inhibitory function of human endothelial cells; Nordoy A et al.; This study was carried out to evaluate the effects of albumin-bound fatty acids on the anti-platelet effects of endothelial cells . Primary cultures of human endothelial cells (ECM), grown in confluent monolayers, were incubated with plasma or growth medium enriched with albumin-bound fatty acids (FA) for 2-20 h . The effects of ECM on ADP-induced platelet aggregation (PA) and collagen-induced PA and prostaglandin synthesis in platelet-rich plasma were tested . ECM released an inhibitor of platelet reactions which resembled the activity of PGI2 (prostacyclin) . The inhibitory activity was increased by preincubation of ECM with arachidonic acid (AA) . A moderate decrease of the activity was obtained by incubation with long-chain saturated, monoenoic and dienoic unsaturated fatty acids . A pronounced decrease of the inhibitor was obtained by incubation with di-homo-gamma-linolenic acid (DHLA) . Paired combinations of AA with the other fatty acids in the incubation medium partially restored the inhibitory activity obtained by the separate FA . The stimulation of the inhibitor by AA was dose dependent and high concentrations of AA reduced this activity . The present study indicates that the quantity and quality of the plasma free fatty acids can affect the endothelial cells' ability to act as a non-thrombogenic surface.

J Biochem (Tokyo), 1979 Feb, 85(2), 591 - 9
Studies on cellulases of a phytopathogenic fungus, Pyricularia oryzae Cavara . III . Multiplicity of beta-glucosidase, and purification and properties of a second component; Hirayama T et al.; To determine the relationship between the induction patterns of three components of beta-glucosidase of Pyricularia oryzae and carbon sources in the growth medium, various culture conditions were examined . Avicel, hydroxyethylcellulose and methyl-beta-D-glucoside as the carbon source induced both beta-glucosidase components, GB-1 and GB-2, whereas cellobiose and gentiobiose induced only one component, GB-1 . Thus, these two components were induced independently and hence thought to be isozymes . The GB-2 was purified to homogeneity by ion exchange and gel filtration chromatographies from two different cultures on methyl-beta-D-glucoside and Avicel . The specific activity of GB-2 when salicin was used as substrate was approximately 5.9 mg glucose/min/mg protein . GB-2 was found to be an oligomeric glycoprotein, which consisted of two subunits with molecular weight of approximately 120,000, comprising a relatively large number of acidic amino acids and mannose, as is the case with GB-1 . These two isozymes were clearly different in thermostability, GB-2 being more thermolabile than GB-1 . However, the same carboxyl group (pKa 4.2--4.8) was found to be strongly implicated in the formation and dissociation of the enzyme-substrate complex for both of the enzymes, from the analysis of kinetic parameters as a function of pH.

Biochem Genet, 1979 Feb, 17(1-2), 57 - 75
Inborn errors of cobalamin metabolism: effect of cobalamin supplementation in culture on methylmalonyl CoA mutase activity in normal and mutant human fibroblasts; Willard HF et al.; We have examined the effect of addition of hydroxocobalamin to growth medium on the activity of the adenosylcobalamin-requiring enzyme methylmalonyl CoA mutase in normal human fibroblasts and in mutant human fibroblasts derived from patients with inherited methylmalonicacidemia . The mutant cell lines were assigned to four distinct genetic complementation groups (cbl A, cbl B, cbl C, and cbl D), each deficient in some step in the synthesis of adenosylcobalamin from hydroxocobalamin . After control cells were grown in cobalamin-supplemented medium, mutase holoenzyme activitiy increased markedly in a time- and concentration-dependent fashion . Growth in cobalamin-supplemented medium had no effect on mutase activity in some mutant lines belonging to the cbl B group, while activity increased severalfold in other cbl B mutants and in all cbl A, cbl C, and cbl D mutants examined, although mutase activity was still less than 10% of control . Comparison of mutase holoenzyme activity and total propionate pathway activity suggests that enhancement of mutase activity in mutant cells after cobalamin supplementation to values 5--10% of control may be sufficient to overcome the inherited metabolic block and to restore total pathway activity to normal.

Mol Gen Genet, 1979 Jan 16, 169(1), 63 - 6
Reversal of protection by light of the ethidium bromide induced petite mutation in yeast; Hixon SC et al.; An intermediate in the ethidium bromide (EB) induced petite mutation pathway may be destabilized by daylight light to cause a reversion to the normal grande phenotype . Starved cells preincubated in the dark for up to 6 h with 100 microgram/ml EB could be reverted to grandes after one hour of light exposure, whereas similarly treated cells maintained in the dark expressed the petite mutation in more than 80 percent of the population . In addition, the production of petite mutants by EB in buffer could be prevented if cell suspensions were exposed to light immediately upon the addition of EB . Photoreversal of the EB-derived petite mutation in growing cells was less efficient presumably because the availability of an energy source caused a continuation of mutation events beyond the light revertible step to a non-reversible fixation of the mutation . Cells treated with EB in growth media at 4 degrees C were more responsive to light protection and reversal of the mutation . This may be due to the cold inhibition of an enzyme which comes into play beyond the light sensitive step in the mutation pathway.

J Supramol Struct, 1979, 10(1), 39 - 50
A possible modulation of acetylcholine receptors of embryonic chick muscle cells by alpha-bungarotoxin; Elson HF; Acetylcholine receptors were assayed with alpha-bugarotoxin on embryonic chick skeletal muscle growing in primary cell culture . Toxin was bound specifically to muscle cells and could be competed with D-tubocurarine . Two dissociation constants were obtained by equilibrium binding: 7.2 x 10(-9)M and 2.7 x 10(-7)M at 25 degrees C . Two sets of rate constants were also obtained from dissociation kinetics . There are five times more low affinity sites on cells than high affinity sites . The average density of high-affinity receptors is about 200/micrometers2 . A time course of toxin binding to receptors at 37 degrees C in growth medium revealed that under conditions permitting growth and metabolism, toxin bound to cells was lost . The possibility that the growth medium was inactivating toxin molecules was ruled out by showing that unbound toxin molecules in the medium were fully capable of binding to fresh cultures.

Folia Microbiol (Praha), 1979, 24(5), 389 - 95
Morphogenic effect of 2-deoxy-D-arabino-hexose on Rhodosporidium toruloides; Sipiczki M et al.; The presence of 2-deoxy-D-arabino-hexose in the growth medium caused marked morphological changes in the cells of Rhodosporidium toruloides . The originally elongated ellipsoidal cells grew spherically in the presence of the deoxy-sugar, displayed differences in cell division and separation, and were larger than the control cells . After exhaustion of glucose from the medium the cells died, although no lysis was observed . The morphological changes were accompanied by significant alterations in the carbohydrate composition of the cell wall . The wall of R . toruloides grown in the presence of the deoxy-sugar contains higher proportions of chitin and glucan, while the relative contents of mannose and galactose polymers decreased drastically in comparison to normal cells.

Biochimie, 1979, 61(8), 923 - 30
Demonstration of growth in porcine thyroid cell culture; Fayet G et al.; Eagle's minimum essential medium supplemented with 20 per cent newborn calf serum (N.C.S.) allows porcine thyroid cell survival but not cell growth in vitro . In NCTC 109 medium supplemented with 20 per cent N.C.S . these cells actively grow and may be serially propagated . Cell population doubling time expressed as DNA doubling value is 3.5 days at 37 degrees C in 95 per cent air-5 per cent CO2 . Thyrotropin does not affect porcine thyroid cell multiplication in vitro but stimulates the plating efficiency in primary cultures to about 130 per cent of controls . Cell selection was obtained by replacing media with Earle's balanced salt solution . This operation provoked death of nearly all cells by day 18 but subsequent addition of growth medium resulted in proliferation of epithelial cell clones . From generation 2 to generation 8, cells produce thyroglobulin but they do not actively trap iodide nor form follicles when thyrotropin is added to the media . Cell selection, demonstration of growth, as well as freeze-storage techniques described in this paper permit selection and storage of porcine thyroid cells and the potential constitution of cell collections.

Z Allg Mikrobiol, 1979, 19(3), 187 - 94
{Biosynthesis of the cell wall polysaccharides, mannan and glucan, by Candida spec . H as indication of different pathways of glucose breakdown}; Rober B et al.; The catabolic and anabolic D-glucose transformation of the yeast Candida spec . H has been studied . By using 1-14C-D-glucose and 6-14C-D-glucose, measuring the 14CO2 liberation and the label of glucose and mannose isolated from glucan and mannan, the following results have been obtained.1 . Beginning with 100 micromoles glucose . ml-1 in the batch growth medium, at first on an average 64% of the glucose having been catabolized to CO2 are directly decarboxylated to pentose phosphate by pentose phosphate pathway (PPW) . Later on at an exogen concentration of 70 micromoles.ml-1 73% of glucose on an average having been catabolised to CO2 undergoes transformation via glycolyse and tricarbonacid cycle (G-TCC) . 2 . Only after getting this glucose concentration the maximal hexose incorporation rate into glucan and mannan can be obtained . 3 . 20--40% of the hexose channeled into the polysaccharid-biosynthesis have been prepared by resynthesis from pentose phosphate via PPW . 4 . The results are discussed in connection with the observed crabtree effect.

Biochimie, 1979, 61(4), 473 - 82
General and lysin specific control of saccharopine dehydrogenase levels in the yeast Saccharomycopsis lipolytica; Gaillardin CM et al.; Lysine supplementation of the growth medium of a wild type strain of the yeast Saccharomycopsis lipolytica specifically results in saccharopine dehydrogenase repression . Starvation of the strain for histidine triggers a general depression of various histidine, leucine, arginine and lysine biosynthetic enzymes, including saccharopine dehydrogenase . These two types of control, specific and general, act independently on saccharopine dehydrogenase expression, since mutants which fail to respond to the specific control still are sensitive to the general one . These mutants were first selected as unable to catabolize lysine, suggesting that a link may exist between saccharopine dehydrogenase specific regulation and activity of the catabolic pathway.

Genetics, 1979 Jan, 91(1), 53 - 66
Expression of radiation-induced mutations at the arginine permease (CAN1) locus in Saccharomyces cerevisiae; Gocke E et al.; In the yeast Saccharomyces cerevisiae, the expression of resistance to the L-arginine analog, L-canavanine, after mutagenesis, is strongly dependent on the metabolic state of the cell . The frequency of mutations recovered after exposure to ultraviolet light or X rays was measured under a variety of culture conditions . The results indicate that the frequency of mutants recovered is determined by the following three factors: (1) The potential mutants still possess enough permease activity to take up some of the cell poison, and some are therefore killed before they can express the mutant genotype . The sensitivity is strongly influenced by the endogenous free arginine, which is in turn influenced by the growth medium . (2) The rapid decay of the permease molecules and the inability of the potential mutants to resynthesize this protein results in a rapidly increasing change of expression when selection is delayed . (3) During the time when the permease activity is decaying, repair of the mutagen-induced damage appears to occur.

Genetics, 1979 Jan, 91(1), 35 - 51
The CAN1 locus of Saccharomyces cerevisiae: fine-structure analysis and forward mutation rates; Whelan WL et al.; A system of strains and growth media was developed to allow efficient detection of forward mutation, reversion, complementation, and suppression at the canavanine-resistance (CAN1) locus of Saccharomyces cerevisiae . Genetic fine-structure analysis revealed that the map length is at least 40, and possibly as much as 60 X-ray map units; this is the longest gene map yet reported in S . cerevisiae . Allelic complementation was not observed, despite testing of a large number of allele pairs, and alleles suppressible by the ochre suppressor SUP11 were absent from a sample of 48 spontaneous mutants and occurred infrequently (7%) among a sample of ultraviolet-induced mutants . Infrequent mutant types included canavanine-resistant mutants capable of arginine uptake and alleles thought to represent deletions or inversions . In contrast to previous reports in the literature, the spontaneous forward mutation rate at CAN1 did not increase during meiosis.

Cell Tissue Kinet, 1979 Jan, 12(1), 101 - 10
Flow cytometric cell cycle analysis using the quenching of 33258 Hoechst fluorescence by bromodeoxyuridine incorporation; Bohmer RM; Cultures of L cells were grown in medium containing 2.0 mg/l bromodeoxyuridine (BUdR) and stained with the fluorescent dye 33258 Hoechst for flow cytometric analysis . During exposure to BUdR, The cells replace thymidine by BUdR in the newly synthesized DNA . The new DNA is not stainable with 33258 Hoechst, which is highly specific for thymidine . The temporal development of the fluorescence distributions after addition of BUdR to the growth medium has been investigated in the flow cytometer, and the data were used to calculate the mean durations of the phases G1, S and G2 + M in exponentially growing cultures as well as the cycle transit times in synchronized cultures . The percentage of non-cycling cells was determined in each experiment.

J Bacteriol, 1979 Jan, 137(1), 545 - 55
Bacteriophage T4D receptors and the Escherichia coli cell wall structure: role of spherical particles and protein b of the cell wall in bacteriophage infection; Zorzopulos J et al.; The nature of the interaction of bacteriophage T4D and the outer cell wall of its host, Escherichia coli B, has been investigated . Bacteria with altered or modified cell walls have been obtained by two different growth procedures: (i) growth in high osmolarity medium or (ii) growth in broth in the presence of divalent heavy metal ions . When these altered host cells were washed and subsequently added to regular growth medium, they interacted with added phage particles, but successful infection did not occur . Most of the phage particles released from these treated cells were observed to have full heads and an altered tail structure . The altered phage tails had contracted sheaths and unusual pieces of the bacterial cell wall attached to the distal portion of the exposed phage tail tube . Phage released from bacteria grown in the high osmolarity medium had attached cell wall pieces of two major types, these pieces being either 40 or 21 nm in diameter . The smaller-type cell wall pieces (21 nm) were formed by three spheres each measuring 7 nm in diameter . Phage particles released from cells previously exposed to the divalent metal ions had only one 7-nm cell wall sphere attached to the distal end of the tail tube . It was found that these 7-nm spheres (i) are normal components of the cell wall and are morphologically similar to endotoxin, (ii) are held in place on the cell wall by a component of the cell wall called protein b, and (iii) are most likely the site of penetration of the phage tail tube through which the phage DNA enters the host cell.

Z Mikrosk Anat Forsch, 1979, 93(5), 820 - 8
{The effect of a synthetic tripeptide nervous tissue cultured in vitro}; Lindner G et al.; Explants from chick embryo PNS (ganglion trigeminale) and from CNS of embryonal rats (hippocampus) and dissociated cells from chick embryo cerebral hemispheres were cultivated in maximow chambers in the presence of various concentrations of placental serum and of a chemically synthesized tripeptide Gly-His-Lys . 1 . The presence of tripeptide in the nutrient medium with a low concentration of serum did not compensate the outgrowth of nerve fibers, that take place in the growth medium . 2 . In the presence of tripeptide in the nutrient medium with low concentration of serum the index of growth area increased significantly . 3 . Within the first days in cell cultures 0,01 microgram tripeptide pro ml medium stimulated the outgrowth of neuronal processes . 4 . The experiments indicated, that the tripeptide did not replace the serum . The possible role of tripeptide as a system in controlling neuron-glial ratio in vitro is discussed.

Comp Biochem Physiol B, 1979, 64(2), 219 - 24
Zinc effects on LDH, MDH and alkaline phosphatase from cultures of fathead minnow cells; Adragna PJ et al.; 1 . Three purported zinc metalloenzymes have been investigated from cell cultures of the fathead minnow (Pimephales promelas) . 2 . With the addition of increasingly higher concentrations of zinc to the tissue culture medium, the specific activity of LDH increased . 3 . The results with MDH were equivocal . 4 . The specific activity of alkaline phosphatase decreased in the presence of increasing amounts of zinc in the growth medium . 5 . Zinc exogenously added to the LDH enzyme assay did not alter the LDH enzyme activity of cells grown without zinc.

Arch Microbiol, 1979, 123(3), 251 - 8
Adenylyl cyclase deficient cr-1 (Crisp) mutant of Neurospora crassa: cyclic AMP-dependent nutritional deficiencies; Terenzi HF et al.; The inability to synthesize cyclic AMP drastically affects the nutritional metabolism of Neurospora crassa . The adenylyl cyclase-less mutant cr-1 (crisp) did not utilize several carbon sources, including glycerol, mannitol, arabinose, and casaminoacids . However, in glucose or acetate it grew as well as the wild type . The following evidence suggested that these nutritional deficiencies were a direct result of the cr-1 mutation: (i), in crosses to wild type they segregated together with the crisp morphological marker; (ii), cyclic AMP added to the cr-1 mutant growth medium overcame the nutritional deficiencies; (iii), the cyclic AMP effect was specific for the crisp mutant, for it was not observed with the wild type, nor with a spontaneous glycerol-utilizing cr-1 strain.

Microbiol Immunol, 1979, 23(7), 643 - 50
Effect of nucleosides on interferon production and development of antiviral state induced by poly I.poly C; Machida H et al.; Effect of nucleosides both on induction of antiviral state in chick embryo cells (CEC) or rabbit kidney cells (RK13) and on interferon production in RK13 or mouse fibroblast cells (L cells) by polyriboinosinic-polyribocytidylic acid (poly I.poly C) was studied . Addition of inosine or a fifty-fifty mixture of inosine and uridine at a final concentration of 0.1 mM to 10 mM to a growth medium enhanced development of antiviral state in CEC . The nucleoside effect was also observed in RK13 at 0.1 mM but not at a concentration higher than 1 mM . Interferon production in RK13 by superinduction (sequential treatment with metabolic inhibitors after exposure to poly I.poly C) was enhanced 1.5- to 4.0-fold by addition of the nucleoside mixture to the growth medium . When RK13 was pretreated with 10 units per ml of interferon and then superinduced by inhibitors, the enhancing effect of nucleosides on interferon production was not observed . Interferon production in L cells was potentiated a little by addition of 1 mM of the nucleoside mixture to the growth medium . The effect of nucleoside was not observed when the nucleosides were added after exposure to poly I.poly C . The nucleoside effect may be applicable for production of high titered interferon.

Dev Biol Stand, 1979, 42, 71 - 4
Some aspects of FMDV-production in growing cells and a closed system for concentration of FMDV by polyethylene glycol; Barteling SJ; Different commercially available peptone preparations, all derived by enzymatic digestion of meat, were tested for their ability to replace the individual amino acids and polyethylene glycol (PEG)-treated serum in BHK suspended cell culture growth medium . Cell growth was not impaired if the individual amino acids were replaced by 3 g/l of peptone in combination with 3 g/l LAH and 5% PEG-treated bovine serum . The concentration of the latter could be reduced to 1% by gradually lowering the concentration in successive cell passages . No significant differences in growth stimulating properties were observed between the peptone preparations . The virus produced was concentrated and partly purified by precipitation with PEG, collection of the precipitate by filter-aid filtration and direct elution from filter cake in the filter by pumping one tenth the original volume of buffer through the filter . The whole procedure was performed in a simple closed system, offering maximum guarantee of bacteriological sterility and preventing virus aerosol formation in the surroundings.

Enzyme, 1979, 24(4), 255 - 60
Adenosine triphosphatase of Aspergillus nidulans: existence of isoenzymes of Ca2+-ATPase; Selvam R et al.; Ca2+-ATPase activity increased five- to six fold when the cells were subjected to growth at 37 degrees C in protein hydrolysate-supplemented media as compared to that of the cells grown in minimal media . One major isoenzyme and one minor isoenzyme were present in minimal-medium-grown cells while two major isoenzymes were present in the cells grown in protein-supplemented media . When the cells were subjected to heat stress (43 degrees C), they exhibited significantly decreased activity as compared to 37 degrees C grown cells . However, all the cultures subjected to growth at 43 degrees C showed two isoenzymes independent of growth medium.

Clin Toxicol, 1979, 14(5), 489 - 98
Metabolism of carbaryl by kidney, liver, and lung from human postembryonic fetal autopsy tissue; Chin BH et al.; Metabolic profiles of carbaryl in human postembryonic fetal autopsy tissue were determined using an in vitro tissue-maintenance technique . 1-Naphthyl-14C or N-methyl-14C-carbaryl was applied to growth medium containing explants of the tissue . Each mixture was incubated for 18 hr and the medium analyzed by DEAE-cellulose column chromatography . Fetal liver performed the metabolic processes of demethylation, hydrolysis, hydroxylation, and oxidation, followed by conjugation, as was found with adult liver . However, the anionics from fetal liver amounts to 20% of those found with adult liver . The kidney made naphthyl glucuronide and naphthyl sulfate, whereas the lung produced naphthyl sulfate from carbaryl . The metabolic activities of the fetal kidney and lung were close to the corresponding human adult tissues based upon the anionic metabolites found and the amount of unmetabolized carbaryl in the medium after 18 hr of incubation . Silica gel chromatography of ether-extractable neutral fractions from DEAE-cellulose revealed 3,4, and 9 ether-extractable metabolites from lung, kidney, and liver, respectively . The present study shows that the in vitro technique is capable of semiquantitatively demonstrating the metabolic activities of specific organs from the human fetus.

Prostaglandins, 1979 Jan, 17(1), 53 - 9
Arachidonic acid level in cellular lipids determines the amount of prostaglandins synthesized during cell growth in tissue culture; Hong SL et al.; Methylcholanthrene transformed mouse fibroblast cells can be induced to synthesize prostaglandins by a short term incubation with various vasoactive agents including serum, bradykinin and thrombin or in response to mechanical detachment from the culture dish . The ability of the cells to synthesize prostaglandins upon stimulation changes during growth of the culture on the dish; the response is maximal on the first day after inoculation and decreased sharply thereafter . Feeding of the cells with fresh growth medium enhances prostaglandin production induced by all stimuli . The difference in the cell response during growth is probably not due to change of prostaglandin synthetase activity since the specific enzyme activities assayed with microsomal preparations of cells harvested from the first and third day culture are similar . However, analysis of the cellular content of arachidonic acid after saponification of the total lipid extract of cells harvested at different days of growth reveals that the level of arachidonic acid per cell during growth is parallel to the response to stimuli . It is maximal on the first day and decreases sharply on the second day and stays low on the third day . Our study suggests that the level of arachidonic acid in the cell governs the extent of prostaglandin synthesis upon stimulation.

J Bacteriol, 1979 Jan, 137(1), 62 - 8
Effect of ethylenediaminetetraacetate on phospholipids and outer membrane function in Escherichia coli; Hardaway KL et al.; Treatment of Escherichia coli K-12 strain S15, containing a normal amount of phospholipase A, with ethylenediaminetetraacetate (EDTA) resulted in an increase in sensitivity of the organism to actinomycin D . Strain S17, a mutant deficient in both detergent-resistant phospholipase A and detergent-sensitive phospholipase A, was considerably less sensitive to the antibiotic after the treatment . Both strains released lipopolysaccharide after EDTA treatment, indicating that this outer membrane component alone is not the barrier to actinomycin in these organisms . The phospholipase A-deficient strain released less alkaline phosphatase, a periplasmic enzyme . EDTA treatment of S15 resulted in the accumulation of free fatty acids, indicative of phospholipase A activation . Cells briefly treated with EDTA regained the barrier to actinomycin when incubated in growth media, and the cessation of the accumulation of free fatty acids was in approximate temporal agreement with restoration of the barrier . Cells in which phospholipase A was activated by brief exposure to EDTA synthesized relatively more phosphatidylethanolamine than did untreated cells in the initial period after dilution into growth media . These experiments suggest that the EDTA-induced loss of outer membrane barrier function of E . coli K-12 is mediated through the activation of phospholipase A.

Z Allg Mikrobiol, 1979, 19(7), 467 - 72
Effect of nutrients on the toxicity of pesticides carbofuran and hexachlorocyclohexane to blue-green alga Nostoc muscorum; Kar S et al.; The effects of various levels of nutrients like potassium phosphate (dibasic), calcium nitrate, and calcium chloride individually and in combinations were studied on the toxicity of the commonly used pesticides carbofuran and hexachlorocyclohexane (HCH) in growth medium to the N2-fixing blue-green alga Nostoc muscorum . It was observed that all these chemicals had some effects on toxicity . The toxicity of both carbofuran and HCH was reduced to some extent in the presence of higher concentrations of the nutrients when compared to normal levels of the chemicals in the medium . The higher doses of nutrients in combinations antagonized the effect of individual treatment and enhanced the toxicity of pesticides.

Zentralbl Bakteriol Naturwiss, 1979, 134(4), 325 - 34
L-asparaginase-producing Streptomyces from the soil of Kuwait; Mostafa SA et al.; Five actinomycete isolates (all belonged to the genus Streptomyces), capable of producing detectable amounts of L-asparaginase, were isolated from the soil of Kuwait after enrichment . The three most potent enzyme producers were identified as different strains of Streptomyces collinus . Factors affecting enzyme production by the strongest strain were examined . Synthetic media with asparagine as a nitrogen source stimulated more enzyme production than natural media . Starch and asparagine at final concentrations of 1 and 0.8%, respectively, were optimum for enzyme production . An initial pH of 8.5 for the growth medium and an incubation temperature of 28-30 degrees C in a static culture for 6 days stimulated enzyme production by the examined strain of Streptomyces collinus.

Zentralbl Bakteriol Naturwiss, 1979, 134(5), 429 - 36
Production of L-asparaginase by Streptomyces karnatakensis and Streptomyces venezuelae; Mostafa SA; Production of L-asparaginase by two soil isolates, identified as S . karnatakensis and S . venezuelae, was investigated under different environmental and nutritional conditions . The presence of carbon sources, other than starch, in the growth medium or amino acids, other than L-asparagine-inhibited the enzyme biosynthesis . L-aspartic inhibited growth and enzyme production, due to a feedback mechanism, and/or lowering the pH value . Both organisms were stimulated to produce more enzyme with increasing concentrations of starch and L-asparagine, however, the optimum starch and L-asparagine concentration depended on the tolerance of the organism to low and high pH, respectively . Aeration stimulated growth, but not enzyme production, and both organisms produced more enzyme in static cultures than in shaken cultures.

Biochimie, 1979, 61(5-6), 711 - 7
Variations in some molecular events during the early phases of the reuber H 35 hepatoma cell cycle . I . Glucocorticoid induction of tyrosine aminotransferase; Van Wijk R et al.; 1 . Reuber H 35 hepatoma cell cultures were syncrhonized by serum depletion of the growth medium for 72 hr, which results in arrest of the cells in the G0 or G1 phase of the cell cycle . 2 . Induction of tyrosine aminotransferase by dexamethasone was studied . Induction along the cell cycle varies with respect to the sensitivity of the cell towards low hormone concentration and the maximum effect elicited by the hormone . 3 . Scatchard analyses of receptor- {3H}triamcinolone binding was performed in cell extracts prepared from cells at various times of G1 and S . Variations were observed in the concentration of glucocorticoid receptor as well as in the affinity of the receptor for the hormone . 4 . During the latter part of the cell cycle, variations in the concentrations of the receptor could not explain the variation in enzyme induction, since the maximum rate of induction decreased while an increase in receptor activity still occurred.

Cell Tissue Res, 1978 Dec 28, 195(2), 317 - 29
Complete differentiation of adipocyte precursors . A culture system for studying the cellular nature of adipose tissue; Van RL et al.; Evidence for the complete morphological maturation of precursor cells into adipocytes in vitro is presented . Cells were isolated from the stromal fraction of adipose tissue from adult humans and from rats and were grown in culture . Abdominal skin fibroblasts were used as controls . All cell strains were initially fusiform and replicated . On reaching monolayer confluency, they were transferred to an enriched growth medium in which the human and rat adipocyte precursors differentiated into a homogeneous population of cells, morphologically indistinguishable from mature adipocytes . In contrast, skin fibroblasts from the same person or animal, and grown under identical culture conditions, did not accumulate lipid and retained their fusiform contour . The same results were obtained in the first six subcultures that were studied . Thus, there is firm evidence that fat tissue of adult humans and rats contains adipocyte precursors that differentiate into mature fat cells . The culture system that has been described will facilitate the elucidation of the factors involved in replication and differentiation of adipocyte precursors.

Biochim Biophys Acta, 1978 Dec 18, 544(3), 615 - 23
Regulation of the biosynthesis of cytochrome P-450 in brewer's yeast . Role of cyclic AMP; Wiseman A et al.; The drug metabolising enzyme cytochrome P-450 has been studied in great detail in mammalian systems and its presence in microorganisms is also well established . However, neither its function nor its means of control in brewer's yeast, Saccharomyces cerevisiae, has been investigated . We demonstrate here using yeast protoplasts that it is the intracellular concentration of cyclic AMP which controls, by repression, the de novo synthesis of the enzyme, and also that cyclic AMP concentrations are in turn inversely related to the concentration of glucose in the yeast growth medium.

Growth, 1978 Dec, 42(4), 427 - 33
Canine kidney cells: III . Neutral lipids, phospholipids and fatty acids of primary canine kidney cells in monolayer culture; Hougland AE et al.; Neutral lipids, phospholipids and fatty acids were studied in monolayer grown primary canine kidney whole cells and their plasma membranes which were isolated by the Warren fluorescein-mercuric acetate technique . Triglyceride and unesterified cholesterol were the predominant neutral lipids of whole cells, while cholesterol ester, free fatty acid, and unesterified cholesterol were the major neutral lipids of plasma membranes . The total neutral lipid value is about 2-fold greater in plasma membranes than in whole cells . Phosphatidyl ethanolamine and physophatidyl choline are the major phospholipids of whole cells and plasma membranes . The total phospholipid value is almost 1.8-fold greater in plasma membranes than in whole cells . The fatty acid profiles of both whole cells and plasma membranes differ from that of calf serum used in the growth medium . The amount of unsaturated fatty acids is considerably lower while the amount of saturated fatty acids is higher than the corresponding values obtained in calf serum.

Can J Microbiol, 1978 Dec, 24(12), 1520 - 5
Characterization of the bacterial flora associated with root systems of Pinus contorta var . latifolia; Dangerfield JA et al.; Root systems of young and mature lodgepole pine (Pinus contorta Dougl . var . latifolia Englem.) were removed from forest stands and the associated aerobic bacterial flora isolated . Characterization of rhizoplane and control soil isolates from these tree root systems demonstrated differences from that reported for agricultural crops . Ammonifying, proteolytic, and amylolytic organisms were proportionately reduced within the rhizoplane . The rhizoplane organisms grew more slowly than the control soil isolates, although they responded in greater numbers to the addition of an amino acid supplement to the growth media . The rhizoplane organisms also showed an increased ability to solubilize phosphate . The chitinolytic organisms were suppressed within the rhizoplane of the mature tree but were stimulated by the young trees . With this exception, the rhizoplane microflora of older and younger trees were similar.

Tropenmed Parasitol, 1978 Dec, 29(4), 432 - 4
A method of mass cultivation of Toxoplasma gondii in cell culture; Braveny I et al.; Large quantities of Toxoplasma gondii were cultivated in human larynx carcinoma cells (H.Ep 2, heteroploid) . Virulent Toxoplasma gondii, strain RH, which were obtained from the peritoneal exsudate of mice 2 days after infection served as inoculum . As culture medium for the cells and for growth medium, Minimum Essential Medium (MEM) supplemented by 5% foetal calf serum and 200,000 IE/1 Penicillin plus 20 mg/1 Sulmycin was used . 2--3 days after inoculation, 150--200 times the amount of the inoculated Toxoplasmas could be harvested in one or several harvests.

J Cell Physiol, 1978 Dec, 97(3 Pt 1), 267 - 83
Inhibition of basal protein degradation in rat embryo fibroblasts by cycloheximide: correlation with activities of lysosomal proteases; Amenta JS et al.; Rat embryo fibroblasts were grown in medium containing 14C-leucine and 3H-thymidine . After a 24-hour chase in nonlabeled medium, cultures were placed in either fresh growth medium or medium containing 10-20 microgram/ml cycloheximide . Cell monolayers were processed at daily intervals for three days . Four hours prior to processing, cultures were placed in fresh medium and the accumulation rate of trichloroacetic acid soluble 14C in the media assayed . Cycloheximide effects a progressive decrease in the fractional degradation rate of the labeled cell protein, primarily during the first 24 hours . The specific activities of cathepsin D, cathepsin B, and neutral protease correlate closely with the fractional degradation rate . Other lysosomal hydrolases show little change during this period . The activities of the lysosomal proteases approach a new steady state which is correlated with the new steady state level of protein synthesis . A model is proposed which relates the rate of protein breakdown in the cell to the level of protein synthesis . The data also suggests the possibility that subpopulations of high turnover and low turnover cells exist in these cultures.

J Bacteriol, 1978 Dec, 136(3), 1184 - 6
Ureotelism and ammonotelism in trypanosomatids; Yoshida N et al.; According to their genera, trypanosomatids excrete urea, ammonia, or both . Species of Herpetomonas and Trypanosoma are ammonotelic . Species of Leishmania, Leptomonas, Crithidia, and Blastocrithidia can be ureotelic, ammonotelic, or both, depending on growth media composition.

Biochim Biophys Acta, 1978 Dec 1, 544(2), 441 - 4
Extracellular matrix metabolism by chondrocytes . VI . Concomitant depression by exogenous levels of proteoglycan of collagen and proteoglycan synthesis by chondrocytes; Handley CJ et al.; The synthesis of collagen and proteoglycans by cultured chondrocytes, as measured by the incorporation of L-{3H}proline into hydroxyproline and {3H}acetate into glycosaminoglycans, was shown to be depressed by 58% and 39%, respectively, by the addition of exogenous proteoglycan at a concentration of 10 mg/ml growth media . The incorporation of L-{3H}proline into acid-insoluble protein remained unaltered in the presence of the proteoglycan . It was concluded that the effect was depressing the activity on the enzymatic steps, associated with the endoplasmic reticulum, which are responsible for the post-translational modification of collagen and proteoglycan.

Natl Cancer Inst Monogr, 1978 Dec, (50), 107 - 14
Multiple pathways of DNA repair and their possible roles in mutagenesis; Smith KC; In studies on bacteria, the excision repair of UVR-induced DNA base damage has been divided into two major pathways on the basis of physiologic requirements and genetic control . The major pathway requires a functional polA+ gene, does not need complete growth medium, is largely error free, and produces short patches during repair . The second pathway requires complete growth medium and functional recA+, recB+, recC+, lexA+, uvrD+, and polC+ genes, is mutagenic, and produces long patches during repair . A second type of ecision repair exists, in which the modified base is removed by a DNA glycosylase, and the chain is nicked by an apurinic (apyrimidinic) acid endonuclease . Subsequent events are presumed similar to the above excision repair process . The postreplication repair system has been divided into at least four distinct pathways, three of which depend on functional recB+, lexA+, and uvrD+ genes, and are error free . A fourth pathway depends on the above gene products but is blocked by postirradiation treatment with chloramphenicol, and may be the UV-inducible, error-prone, mutagenic pathway of repair ("SOS repair") . A possible fifth pathway is dependent on a functional recF+ gene and is independent of the recB+-dependent pathway . Mutagenesis is the result of error-prone DNA repair, and evidence is growing that carcinogenesis is also the result of error-prone repair . Therefore, a complete understanding of DNA repair is crucial to a complete understanding of the molecular basis of carcinogenesis.

Mol Gen Genet, 1978 Nov 16, 167(1), 37 - 41
The involvement of DNA polymerase I in the postreplication repair of ultraviolet radiation-induced damage in Escherichia coli K-12; Barfknecht TR et al.; A deficiency in DNA polymerase I increased the ultraviolet (UV) radiation sensitivity of a uvrA strain of Escherichia coli K-12 when plated on minimal growth medium . The slope of the survival curve for the uvrA polA strain was 2.0-times greater than that for the uvrA strain . The fluence-dependent yield of unrepaired deoxyribonucleic acid (DNA) parental-strand breaks following UV irradiation and incubation in minimal growth medium was similar in both strains . However, the fluence-dependent yield of unrepaired DNA daughter-strand gaps observed following UV irradiation was 1.8-fold greater in the uvrA polA strain than in the uvrA strain . These results suggest that DNA polymerase I is involved in the filling of at least some daughter-strand gaps during postreplication repair . Also, the uvrA polA strain was sensitized by a post-UV treatment with chloramphenicol (CAP) to a similar extent as was the uvrA strain, indicating that DNA polymerase I is not involved in the CAP-inhibitable pathway of postreplication repair.

Biochim Biophys Acta, 1978 Nov 15, 544(1), 138 - 43
Surface analysis and depth profiles of calcium in hepatoma cells during pyruvate-induced DNA synthesis; Pickart L et al.; Induction of DNA synthesis is associated with increased uptake of calcium in cultured cells . Calcium distribution within the plasma membrane and adjacent cytoplasmic layers of hepatoma cells was investigated with X-ray photoelectron spectroscopy and oxygen plasma etching . Cells in minimal growth medium initiate active DNA synthesis 16 h after addition of sodium pyruvate . Cells stimulated with pyruvate and pyruvate-free controls were analysed by X-ray photoelectron spectroscopy--oxygen plasma etching at 0--40 A (layer I), 0--450 A (layer II) and 0--4000 A (layer III from the outer cell surface . Calcium concentrations were elevated in induced cells compared with controls: +20% in layer I, +60% in layer II, and +300% in layer III . As the plasma membrane is 90--120 A thick, these results indicate that pyruvate-induced DNA synthesis is preceded by an increase in calcium, most marked in the cytoplasm subjacent to the plasma membrane, moderate at its inner surface, and minimal at its outer surface.

Biochim Biophys Acta, 1978 Nov 10, 527(1), 31 - 41
Subcellular localization and levels of aminopeptidases and dipeptidase in Saccharomyces cerevisiae; Frey J et al.; Three aminopeptidases (L-aminoacyl L-peptide hydrolases, EC 3.4.11) and a single dipeptidase (L-aminoacyl L-amino acid hydrolase, EC 3.4.13) are present in homogenates of Saccharomyces cerevisiae . Bassed on differences in substrate specificity and the sensitivity to Zn2+ activation, methods were developed that allow the selective assay of these enzymes in crude cell extracts . Experiments with isolated vacuoles showed that aminopeptidase I is the only yeast peptidase located in the vacuolar compartment . Aminopeptidase II (the other major aminopeptidase of yeast) seems to be an external enzyme, located mainly outside the plasmalemma . The synthesis of aminopeptidase I is repressed in media containing more than 1% glucose . In the presence of ammonia as the sole nitrogen source its activity is enhanced 3--10-fold when compared to that in cells grown on peptone . In contrast, the levels of aminopeptidase II and dipeptidase are less markedly dependent on growth medium composition . It is concluded that aminopeptidase II facilitates amino acid uptake by degrading peptides extracellularly, whereas aminopeptidase I is involved in intracellular protein degradation.

J Clin Microbiol, 1978 Nov, 8(5), 516 - 9
Complement fixation antibody test for human nocardiosis; Shainhouse JZ et al.; Complement-fixing antibody was detected in 13 of 16 patients with histological and/or culture evidence of infection with Nocardia species . The antigen used was a filtrate of soluble substances secreted into liquid growth medium by cultures of N . asteroides . Apparent false positives reactions were found in three of three patients with leprosy and two of five patients with tuberculosis--results similar to some previously reported methods . N . asteroides and mycobacteria share antigens . Only the false positives with tuberculosis are considered a diagnostic problem . No reactions were obtained with sera from 26 patients with other infections and 41 unifected individuals . Whereas previous nocardia serodiagnostic methods have a sensitivity of approximately 50%, our overall sensitivity (81%) compares favorably and included 9 of 11 positive tests in immunocompromised nocardiosis patients (a source of false negative reactions with previous methods).

Lab Invest, 1978 Nov, 39(5), 491 - 6
Collagen turnover and the growth state in 3T6 fibroblast cultures; Steinberg J; The metabolic turnover of collagen in 3T6 fibroblast cultures was studied at various stages of growth by compartmental analysis of hydroxyproline content and of the conversion of radioactive proline to hydroxyproline . Quantitative and radioactive hydroxyproline measurements were directly parallel, although the latter method was more sensitive in demonstrating collagen synthesis in all phases of growth . Hydroxyproline formation as an index of collagen synthesis was abruptly accelerated at the time of confluence, and was well maintained at the new rate despite a gradual decline in the rate of general protein synthesis . Ethanol fractionation of growth medium proved superior to perchloric acid extraction in providing a pool of soluble hydroxyproline clearly derived from collagen degradation . Breakdown products were released at a constant rate per cell in all growth phases and accumulated to high levels in continuous culture . The fractional rate of collagen breakdown (percentage of hydroxyproline radioactivity) was highest in early logarithmic growth . Its gradual decline as cultures aged reflected the increased hydroxyproline content and improved stability of collagen under these conditions.

In Vitro, 1978 Nov, 14(11), 924 - 34
Prolonged prostaglandin E1 stimulation of cyclic AMP production in transformed and normal WI-38 fibroblasts; Chlapowski FJ et al.; Long-term (48-hr) incubations of either the fibroblast strain WI-38 or its SV40-transformed counterpart, WI-38-VA13-2RA, in growth medium containing 1 micron prostaglandin E1 (PGE1) resulted in a sustained production and release of cyclic AMP from the cells into the medium . Despite the steady production, intracellular levels of the nucleotide decreased, reaching steady-state values within 4 hr of the initial exposure to PGE1 . These values were maintained for the remainder of the 48-hr experimental period . The steady-state levels of intracellular cyclic AMP were higher than those observed in unstimulated cells, and cyclic AMP-dependent protein phosphokinase was in a highly activated state as compared to controls . Under these conditions little change in the growth or morphology of either the normal or transformed cells was observed . In contrast, inhibition of growth, apparent cell death, and unusual morphological changes were observed in both normal and transformed cells when high concentrations of either PGE1 (10 micron) or the phosphodiesterase inhibitor 1-methyl, 3-isobutylxanthine (0.5 mM to 2 mM) were used, which was indicative of toxic effects of the drugs . It was concluded that cyclic AMP-mediated activation of protein phosphokinase does not completely inhibit growth in WI-38 cells or restore normal growth and morphology to the SV40-transformed cells.

Cell, 1978 Nov, 15(3), 813 - 22
Schwann cell growth factors; Raff MC et al.; Purified rat Schwann cells were found to proliferate very slowly in normal growth medium containing 10% fetal calf serum (FCS) . Crude extracts of bovine pituitary or brain markedly enhanced Schwann cell growth, while similar extracts of nerve roots, liver and kidney did not . Pituitary extracts were more potent than brain extracts, and extracts from both anterior and posterior pituitary were active . The mitogenic activity of pituitary extracts was reduced by treatment with trypsin, and abolished by pronase and by boiling . A variety of known anterior and posterior pituitary hormones, as well as fibroblast, epidermal and nerve growth factors, were not mitogenic . FCS (greater than 1%) was required for Schwann cell proliferation, but even high concentrations of FCS did not substitute for pituitary or brain extracts, and serum from various other species did not support Schwann cell growth . Although various agents that increase cyclic AMP levels (such as cholera toxin) had been shown to be Schwann cell mitogens, extracts of pituitary or brain did not increase cyclic AMP levels . Extracts of various bovine tissues, including pituitary, brain, liver and kidney, acted synergistically with cholera toxin in stimulating Schwann cell proliferation, although the increase in cyclic AMP induced by the mixture was not greater than that seen with cholera toxin alone . We conclude that there are at least two separate pathways for stimulating Schwann cell division, only one of which involves an increase in intracellular cyclic AMP.

J Bacteriol, 1978 Nov, 136(2), 647 - 56
Biosynthesis and regulation of fructose-1,6-bisphosphatase and phosphofructokinase in Saccharomyces cerevisiae grown in the presence of glucose and gluconeogenic carbon sources; Foy JJ et al.; The mode of synthesis and the regulation of fructose-1,6-bisphosphatase (Fbpase), a gluconeogenic enzyme, and phosphofructokinase (PFK), a glycolytic enzyme, were investigated in Saccharomyces cerevisiae after growth in the presence of different concentrations of glucose or various gluconeogenic carbon sources . The activity of FBPase appeared in the cells after the complete disappearance of glucose from the growth medium with a concomitant increase of the pH and no significant change in the levels of accumulated ethanol . The appearance of FBPase activity following glucose depletion was dependent upon the synthesis of protein . The FBPase PFK were present in glucose-, ethanol-, glycerol-, lactate-, or pyruvate-grown cells; however, the time of appearance and the levels of both these enzymes varied . The FBPase activity was always higher in 1% glucose-grown cells than in cells grown in the presence of gluconeogenic carbon sources . Phosphoglucose isomerase activity did not vary significantly . Addition of glucose to an FBPase and PFK synthesizing culture resulted in a complete loss, followed by a reappearance, of PFK activity . In the presence of cycloheximide the disappearance of glucose and the changes in the levels of FBPase and PFK were decreased significantly . It is concluded that S . cerevisiae exhibits a more efficient synthesis of FBPase after the exhaustion of glucose compared to the activity present in cells grown in the presence of exogenous gluconeogenic carbon sources . Two metabolically antagonistic enzymes, FBPase and PFK, are present during the transition phase, but not during the exponential phase, of growth, and the decay or inactivation of these enzymes in vivo may be dependent upon a glucose-induced protease activity.

Cancer Res, 1978 Nov, 38(11 Pt 2), 4091 - 100
Unsaturated fatty acid requirements for growth and survival of a rat mammary tumor cell line; Kidwell WR et al.; A cell line, the growth and survival of which is markedly affected by linoleic acid, has been established from a carcinogen-induced rat mammary tumor . The cells have been continuously passaged in 5% rat serum plus 10% fetal calf serum-supplemented medium . The rat serum component was found to be indispensalbe, for when it was omitted the growth rate rapidly declined and the cells died by 5 to 7 days . Removal of the rat serum from the growth medium also resulted in a dramatic loss of Oil Red O-positive droplets in the cells, suggesting that the lipid component of rat serum might be a major growth-promoting principle in rat serum . This is likely since the total lipid fraction, but not the delipidized protein fraction, could largely supplant requirement of the cells for rat serum . Pure linoleic acid was found to be effective in maintaining the cell growth in delipidized serum or in whole fetal calf serum-supplemented medium . Fatty acid analysis revealed a 19-fold higher amount of linoleic acid in rat serum than in fetal calf serum.

J Protozool, 1978 Nov, 25(4), 514 - 25
Glycoproteins released by Leishmania donovani: immunologic relationships with host and bacterial antigens and preliminary biochemical analysis; Decker-Jackson JE et al.; The antigenically active glycoproteins (AAGP) released by Leishmania donovani strain 3S promatigotes into growth media and by amastigotes of this strain into the tissue, e.g . blood, of infected hamsters was found to consist of 6 to 7 antigenically distinct components . The antigenic activity of these glycoproteins was resistant to freeze-thawing, protease treatment, and purification by column chromatography using Sephadex G-100 . This activity, however, was destroyed by Na periodate and altered by boiling; AAGP adhered firmly to Amicon filter (UM2) . The antigenically active substances absorbed UV at 230, 260, 280 nm and gave positive Folin phenol, phenol sulfuric acid, and orcinol reactions . By gel diffusion, the component glycoproteins were found to form lines with concanavalin A and to give reactions to identity and partial identity with human red cells and Mycobacterium butyricum . The possible involvement of the antigenically active glycoproteins in pathogenesis of kala azar is discussed.

Mol Gen Genet, 1978 Oct 30, 166(2), 161 - 5
Mitotic recombination in the absence of synaptonemal complexes in Saccharomyces cerevisiae; Olson LW et al.; Mitotic cells of a diploid strain of Saccharomyces cerevisiae with appropriate markers for the detection of mitotic crossing-over and mitotic gene conversion were irradiated with X-rays . Induction of these recombinational events was strong . After irradiation, cells were incubated in a rich growth medium and samples were removed for studying the possible formation of synaptonemal complexes up to a time when most cells had completed the first post-irradiation cell division . No complexes were found during the entire period of sampling, during which mitotic recombination in G1 (mitotic gene conversion), DNA replication and G2 (mitotic crossing-over) had occurred . These results are interpreted to mean that synaptonemal complexes are not required for mitotic recombination.

Mol Gen Genet, 1978 Oct 30, 166(2), 151 - 9
Meiotic recombination and synaptonemal complexes in Saccharomyces cerevisiae; Olson LW et al.; The course of meiotic recombination, gene conversion and crossing-over, was investigated in Saccharomyces cerevisiae . Gene conversion was used as the selected event by removing cells from a medium inducing and promoting meiosis to a vegetative growth medium selective for convertants . Gene conversion started to increase at the same time as DNA synthesis, and nuclei entered a phase where the chromatin appeared as thread-like structures . Crossing over of linked and unlinked markers also started early but remained at a low level until synaptonemal complexes were formed . However, gene conversion and a limited amount of crossing-over could be completed without synaptonemal complexes . It was concluded that meiotic recombination in yeast can occur as early as during DNA synthesis and does not require the function of synaptonemal complexes . Moreover, the low incidence of crossing-over early in meiosis is attributed to a low frequency of strand isomerization.

Int J Cancer, 1978 Oct 15, 22(4), 441 - 6
Neoplastic transformation of canine embryo cells in vitro by N-methyl-N'-nitro-N-nitrosoguanidine; Rhim JS et al.; A cell line derived from a normal beagle embryo was treated in vitro with various levels of N-methyl-N'-nitro-N-nitrosoguanidine or dimethyl sulfoxide (control) . Cells treated only with the carcinogen underwent morphologic alteration in vitro, and one of these altered cell lines produced tumors subcutaneously when injected into NIH nude mice . The tumorigenic transformed line formed larger cell aggregates and grew in this aggregate form when suspended in liquid growth medium above an agar base.

Biochim Biophys Acta, 1978 Oct 4, 512(3), 557 - 65
Carnitine-induced uptake of L-cartinine into cells from an established cell line from human heart (CCL 27); Molstad P et al.; L-Carnitine is actively transported into Girardi human heart cells, an established cell line from human heart . The present study was undertaken to investigate the effect of different concentrations of L-Carnitine in the growth medium on the rate of uptake of L-{3H} carnitine . Increasing the concentration of L-Carnitine from 2 to 100 mumol/l in the growth medium of cells, increased the rate of uptake of L-{3H} carnitine by about 50% . The maximal effect was reached after approx . 72 h incubation . The increase in rate seemed to be caused by synthesis of increased number of carriers, as judged by the increase of V with unchanged apparent Km for the transport process . This effect of L-carnitine could be inhibited by cycloheximide, indicating the dependence on intact protein synthesis . The morphology of the cells was studied by electron microscopy . No myofilaments were found, thus the cells are dedifferentiated and no longer typical muscular cells.

C R Acad Sci Hebd Seances Acad Sci D, 1978 Oct 2, 287(7), 741 - 3
{Nicotinamide desamidase in the culture medium of neuroblastoma cells}; Dierich A et al.; Important amounts of nicotinic acid appear in the growth medium of neuroblastoma cell cultures . It is shown that an enzyme released by the cells into the growth medium deamidates the nicotinamide supplied by the growth medium to nicotinic acid.

Cell Differ, 1978 Oct, 7(5), 283 - 93
The lack of an inhibitory effect of hyaluronate on chondrogenesis in chick limb-bud mesoderm cells grown in culture; Finch RA et al.; The effect of hyaluronate on chondrogenesis in cultures of chick limb-bud mesoderm cells, derived from stage 20--21, 23--24 and 26 embryos grown at different cell densities and in 3 different culture media, was studied . The results show that hyaluronate at a concentration of 500 microgram/ml, does not consistently produce an inhibition of chondrogenesis in cultures of stage 20--21, 23--24 or 26 limb-bud mesoderm cells in contrast to what has been reported by Toole et al . (1972) . It was demonstrated that under optimal conditions, stage 26 cells grown in the absence of hyaluronate do not form as many cartilage colonies in culture as do cells from stage 20--21 or 23--24 embryos . It was determined that culture medium composed of Eagle's MEM supplemented with 7% horse serum, 3% fetal calf serum and 5% 10-day chick embryo extract supported chondrogenesis significantly better than Ham's F-12 supplemented with 10% fetal calf serum . Our results suggest that the inhibition of chondrogenesis by hyaluronate reported earlier is most likely due to the sub-optimal conditions of growth medium, cell density and embryonic stage than to the hyaluronate treatment.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4699 - 703
Modulation of ornithine decarboxylase activity in Escherichia coli by positive and negative effectors; Kyriakidis DA et al.; Two effectors of ornithine decarboxylase (ODC; L-ornithine carboxy-lyase, EC 4.1.1.17) have been extracted from an ODC- (speC-) mutant, Escherichia coli MA 255 . One of these is an ODC inhibitor (Mr 15,000 +/- 2000) that is labile to trypsin; its activity increases 20-fold in response to increased polyamine levels in the growth medium . It has additional characteristics similar to those of the ODC antizyme of eukaryote cells: it is a noncompetitive inhibitor of ODC; the complex formed between ODC and the ODC inhibitor can be dissociated with salt to provide active ODC and active ODC inhibitor; furthermore, this E . coli ODC inhibitor is inhibitory to eukaryote ODC . A thermostable nondialyzable factor that activates ODC in vitro has also been extracted from MA255; increased polyamine levels in the growth medium caused a 1.6-fold increase in the activity of this ODC activator . Effectors with comparable activities have also been identified in the parent ODC+ (speC+) strain MA197 . The fluctuations of the intracellular levels of these two ODC effectors during the growth of E . coli MA255 have been related to the temporal changes of the activity of ODC in the parent ODC+ MA197 strain . The mode of interaction of these three macromolecules, as reflected in the changes of the activity of ODC, appears to be complex . The results suggest that ODC activity may be controlled post-translationally by macromolecules that act as positive and negative effectors and whose levels fluctuate in response to the concentration of the end products of the reaction.

J Clin Microbiol, 1978 Oct, 8(4), 459 - 62
Selective medium for isolation of Eikenella corrodens from periodontal lesions; Slee AM et al.; The addition of 5 microgram of clindamycin per ml to a modified Todd-Hewitt growth medium permitted the ready enumeration of Eikenella corrodens from deep periodontal lesions because it allowed differential growth amongst the periodontal pocket gram-negative microaerophilic-anaerobic flora, maximized the numbers of E . corrodens in such culture, and inhibited the growth of most of the other confounding microorganisms.

Mod Vet Pract, 1978 Oct, 59(10), 755 - 7
Evaluation of a bovine virus diarrhea vaccine; Chapek ML et al.; Singer Strain bovine virus diarrhea (BVD) modified live-virus vaccine, produced in a continuous bovine cell line using equine serum in the growth medium, evoked a high level of serum antibodies and protected against virulent challenge in vaccinated calves . Transmission of vaccinal virus from vaccinated cattle to susceptible controls did not occur when vaccinated and nonvaccinated cattle were kept in constant contact for 23 days . Postvaccinal reactions to the viral vaccine were not observed in vaccinated cattle from 10 feedlots or in cattle vaccinated with multiple doses of the experimental vaccine.

In Vitro, 1978 Oct, 14(10), 838 - 48
Studies on the persistence of differentiated functions in rat hepatocytes set into primary tissue culture . II . Production of specific exportable proteins and the effect of purine cyclic nucleotides: an immunofluorescent study; Armato U et al.; Immunofluorescent studies showed that even after 15 days in vitro primary neonatal rat hepatocytes contained in their cytoplasm detectable amounts of different adult rat serum proteins, including fibrinogen and proalbumin . Estimation of the intensity of specific fluorescence revealed that in untreated cultures the hepatocytic content of the various exportable antigens progressively diminished between the 5th and 15th day in vitro . Treatment with cAMP (10(-5) M daily) alone increased in hepatocytic cytoplasm, with respect to parallel controls, the content of total exportable proteins and of proalbumin . Daily administration of an equimolar association (10(-5) M) of cAMP with cGMP increased the total protein, proalbumin and fibrinogen content of hepatocytes . Daily treatment with cGMP (10(-5) M) alone caused only light and transitory increases in the content of proalbumin and fibrinogen . Rocket immune electrophoresis showed that the hepatocytic secretion of specific proteins into the growth medium persisted up to the 15th day, although progressively diminishing in intensity . The secretion of total exportable proteins and of albumin, but not of fibrinogen, was stimulated by cGMP used alone or coupled with equimolar cAMP.

Circ Res, 1978 Oct, 43(4), 527 - 34
Lipoproteins and the inhibitory effect of human endothelial cells on platelet function; Nordoy A et al.; We investigated the effect of plasma low density lipoproteins (LDL), very low density lipoproteins (VLDL), and high density lipoproteins (HDL) on the platelet inhibitory effect of primary cultures of human endothelial cell monolayers (ECM) . ECM incubated with lipoprotein-deficient plasma (LDP) for 2 hours at 37 degrees C had an inhibitory effect on ADP- and collagen-induced platelet aggregation and prostaglandin production in platelet-rich plasma similar to that observed when ECM were preincubated with growth medium or plasma . Concentrations of LDL in LDP up to protein concentration of 1600 microgram/ml had an inhibitory effect on the endothelial cells' ability to modulate these platelet reactions . VLDL at the highest concentration (1600 microgram/ml) had a slightly inhibitory effect, whereas HDL showed no such effect . The inhibitory effect of LDL was not observed during the first hour of incubation . When HDL in concentrations similar to or higher than LDL were combined with LDL, the inhibitory effect of LDL was partially reduced . VLDL combined with LDL or HDL did not interfere with the effects of the later fractions . The inhibitory effect of LDL was significantly reduced when LDL were diluted in whole plasma . Prostacyclin which is synthesized and released from the endothelial cells and contributes to the inhibitory effect upon platelets did not change its effect on platelet reactivity by preincubation with the various lipoprotein fractions . The current studies may indicate that LDL have a direct effect on the endothelial cells and that this effect may be partially counteracted by HDL . This effect of LDL on the endothelial cells reduces the endothelium's ability to inhibit platelet aggregation and thus could favor the tendency to thrombus formation.

Endocrinology, 1978 Oct, 103(4), 1245 - 52
Acute stimulated hormone release from cultured GH3 pituitary cells; Ostlund RE Jr et al.; Treatment of cultured rat pituitary GH3 cells with 50 mM KCl in growth medium released 33% of cell PRL and 18% of cell GH with a half-time of 5 min . Hormone in the culture medium was increased 2- to 4-fold over unstimulated levels . The response required calcium; barium and strontium, but not magnesium, could substitute for calcium . Low temperature completely inhibited hormone release, which was also reduced significantly by inhibitors of energy metabolism and by nitrogen . This acute response was similar in ionic requirements, hormones released, and time course to the acute effect of TRH . Like potassium stimulation, TRH resulted in acute release of both PRL and GH . This contrasts with the finding that chronic TRH treatment reduced GH synthesis in GH3 cells . After a 10-min preincubation with potassium, subsequent short incubations with potassium released little hormone unless the cells were allowed to recover by incubation in normal medium for at least 2 h . This acutely releasable hormone pool seems to be located in a membrane-bound subcellular fraction, since GH3 cells did not discharge the cytoplasmic marker enzyme, lactate dehydrogenase, during potassium-stimulated hormone release.

Can J Microbiol, 1978 Oct, 24(10), 1158 - 63
Effects of amino acids on Thiobacillus acidophilus . I . Growth studies with special reference to valine; Proteau G et al.; The heterotrophic growth of Thiobacillus acidophilus was inhibited by branched-chain amino acids; valine, isoleucine, and leucine . The inhibition by valine and leucine were partially reversed by isoleucine, and the inhibition by isoleucine was partially reversed by valine . Inhibitions by methionine or threonine were partially reversed when both amino acids were present in the growth medium . Inhibition by tyrosine was increased by phenylalanine or tryptophan . Cystine completely inhibited growth . Other amino acids tested produced little or no inhibition . Acetohydroxy acid synthetase (AHAS) activity was demonstrated in crude extracts of T . acidophilus . In crude extracts the optimum pH was 8.5 with a shift to 9.0 in the presence of valine . Valine was the only branched-chain amino acid which inhibited the AHAS activity . The presence of only one peak of AHAS activity upon centrifugation in linear glycerol density gradients demonstrated that the AHAS activity sediments as one component.

J Biol Chem, 1978 Sep 25, 253(18), 6341 - 3
Formation of phenylalanine transfer RNA lacking the wye base in Vero cells during methionine starvation; Pergolizzi RG et al.; Vero, a cell line derived from African green monkey kidney, normally contains a single species of tRNAPhe (tRNA2Phe), containing a hypermodified base, wye (originally called Y), next to the 3' end of the anticodon . When methionine is removed from the growth medium, there appears a new tRNAPhe species (tRNA1Phe) lacking the wye base and eluting early from reversed phase chromatography columns . Its appearance is not due to the cessation of cell growth . Addition of methionine to cells containing both species of tRNAPhe leads to the disappearance of tRNA1Phe . When {methyl-3H5methionine is added in the presence of actinomycin D, which blocks new RNA synthesis, label appears in the wye base of tRNA2Phe . These results are consistent with the model that tRNA1Phe is an undermodifed precursor of tRNA2Phe and that methionine is required for modification to the mature form.

Biochim Biophys Acta, 1978 Sep 18, 516(1), 1 - 25
High molecular weight, cell surface-associated glycoprotein (fibronectin) lost in malignant transformation; Vaheri A et al.; Fibronectin is a polymorphic glycoprotein found in blood and tissues of vertebrates and in cultures of adherent vertebrate cells . There are several forms of fibronectin is composed of two high molecular weight subunits held together by forms found in tissues and on and around the surfaces of cultured cells . Soluble fibronectin is composed of two high molecular weight subunits held together by disulfide bonds . Insoluble fibronectin may be covalently cross-linked in larger complexes . Fibronectin has affinities for collagen, fibrin, heparin, and cell surfaces . In culture, fibronectin in growth medium may mediate attachment of cells to substratum, and fibronectin synthesized by cells may mediate adhesion to substratum . The widespread occurrence of fibronectin in basal lamina indicates that may different cell types in vivo abut against a fibronectin-containing matrix . Cultured transformed cells usually lack cell-surface fibronectin, also called large, external transformation-sensitive (LETS) protein . The failure of transformed cells to synthesize or bind fibronectin is paralleled (at least in some systems) by failures to synthesize or bind collagen and proteoglycans . Abnormal synthesis of fibronectin and other matrix components and abnormal interactions with the tissue matrix may account for several phenotypic characteristics of transformed cultured cells and for some of the malignant behavior of neoplastic cells in vivo.

J Biol Chem, 1978 Sep 10, 253(17), 6125 - 31
Regulation of glutamine synthetase by dexamethasone in hepatoma tissue culture cells; Crook RB et al.; In certain lines of hepatoma tissue culture (HTC) cells, glutamine synthetase (EC 6.3.1.2) specific activity is increased 2.5- to 3-fold by the addition of glucocorticoids to the growth media . Actinomycin D blocks both the induction and deinduction of glutamine synthetase by glucocorticoids, suggesting a requirement of RNA synthesis for both processes . Using an antiserum raised against purified rat liver glutamine synthetase, we have precipitated radiolabeled glutamine synthetase from HTC cells . Electrophoresis of the immunoprecipitates on sodium didecyl sulfate-acrylamide gels isolates the subunit of glutamine synthetase and permits the radioactivity in the glutamine synthetase band to be quantitated . Using this technique, we have investigated the effect of dexamethasone, a synthetic glucocorticoid, on the rates of synthesis and degradation of glutamine synthetase . Dexamethasone (10(-7) M) increases the rate of synthesis of glutamine synthetase 2- to 3-fold but has no effect on the rate of glutamine synthetase degradation . The rates of total cell protein synthesis and degradation are not significantly affected by dexamethasone . The presence of actinomycin D at the time of removal of dexamethasone from induced cells prevents the fall in the induced rate of synthesis of glutamine synthetase normally seen when the inhibitor is removed from the culture medium . The regulation of glutamine synthetase by dexamethasone has been compared to the regulation of another dexamethasone-inducible enzyme in HTC cells, tyrosine aminotransferase, and been found to be similar in all parameters studied.

Mol Gen Genet, 1978 Sep 8, 164(3), 295 - 302
Genetic control of invertase formation in Saccharomyces cerevisiae . II . Isolation and characterization of mutants conferring invertase hyperproduction in strain EK-6B carrying the SUC3 gene; Hackel RA et al.; Invertase formation in the yeast Saccharomyces cerevisiae is subject to repression by hexoses in the growth medium . Mutagen-induced (ethyl methanesulfonate or N-methyl-N-nitro-nitrosoguanidine) invertase hyperproducer mutants have been derived from the SUC3 MAL3 strain EK-6B by selecting for their ability to grow on media containing the sugar raffinose plus 2-deoxy-D-glucose (2DG) . Raffinose like sucrose is a betta-fructoside which can be hydrolyzed by yeast invertase (beta-fructoside which can be hydrolyzed by yeast invertase (beta-fructofuranoside fructohydrolase) . These mutants, designated dgr, produce higher levels of invertase (pi-glucosidase levels are also elevated but to a lesser extent) under conditions normally repressing invertase biosynthesis in the parent . Invertases of mutants dgr2 and dgr3 are indistinguishable from that of EK-6B with respect to their Km's for sucrose and thermal labilities . Genetic studies revealed that dgr2 and dgr3 are recessive and unlinked to the SUC3 gene.

Tsitologiia, 1978 Sep, 20(9), 1027 - 32
{DNA replication in HeLa cells after gamma irradiation . II . The periodicity of DNA replication in the process of giant cell formation}; Sheikina TA et al.; HeLa G-63 cells irradiated by 5 krads of 6 degrees Co gamma-rays 1.5--2 hours after mitosis (G1-phase) were incubated in growth medium during 9 days . The number of proliferating and eliminated cells, the content of DNA per cell nucleus, and kinetics of the labeled cell fraction upon 3H-TdR continuous incubation were studied . It has been concluded that: during the giant cell growth the nuclear DNA is replicated periodically without following mitoses; 90% of cells are involved in such a cycle; the duration of the period of DNA synthesis in giant cells is the same as that in non-irradiated cells; the duration of the gap between two successive S-periods in giant cells is 2--6 times as long as the sum of G2+M+G1 periods in the normal non-irradiated cells.

Acta Pharmacol Toxicol (Copenh), 1978 Sep, 43(3), 246 - 50
Effect of fluoride on the activity of ornithine decarboxylase in normal and fluoride resistant LS cells; Honglso JK et al.; Renewal of growth medium caused an induction of ornithine decarboxylase (ODC) activity in LS cells grown in suspension culture . Addition of low concentrations of fluoride ions to the growth medium (up to 1.3 mM) resulted in a further increase in this induction of ODC-activity, whereas addition of 6 mM fluoride caused an inhibition of the induction and resulted in reduced ODC-activity as compared to controls . Since sodium fluoride had no stimulatory or inhibitory effect on the ODC-activity assay, it is likely that the effect is exerted on the regulation of ODC-activity in the cells . The effect of fluoride ions on the induction of ODC-activity upon renewal of the growth medium was markedly less pronounced in fluoride resistant LS cells.

Somatic Cell Genet, 1978 Sep, 4(5), 587 - 601
Biological and biochemical effects of bromodeoxyuridine and deoxycytidine on Syrian hamster melanoma cells; Kaufman ER et al.; The addition of deoxycytidine (dCyd) to the growth medium of cultured Syrian hamster melanoma cells causes a reversal of the toxic effects of 5-bromodeoxyuridine (BrdU) and a decrease in the extent of incorporation of BrdU into nuclear DNA . These effects of dCyd can be accounted for, in part, by the intracellular conversion of the exogenously supplied dCyd to thymidine (dThd) nucleotides which can compete with BrdU nucleotides for incorporation into DNA . To some extent, the conversion of dCyd to dThd nucleotides can be inhibited by increasing the concentration of BrdU in the growth medium . The conversion of dCyd to dThd nucleotides is inhibited completely by aminopterin (Apt), and Apt also prevents dCyd from reversing BrdU toxicity and from decreasing the level of BrdU incorporation into nuclear DNA . In a clone of Syrian hamster melanoma cells, increasing the concentration of dCyd in the growth medium from 1 micron to 1000 micron resulted in a progressive increase in the percentage of dThd residues in nuclear DNA being derived from the exogenous dCyd, until more than 90% of the dThd residues came from the exogenous dCyd . However, despite the increasing amount of dThd derived from exogenous dCyd, there was a plateau in the decrease in BrdU incorporation into nuclear DNA at concentrations of dCyd above 8 micron.

J Clin Invest, 1978 Sep, 62(3), 503 - 8
Promotion of human adipocyte precursor replication by 17beta-estradiol in culture; Roncari DA et al.; The influence of 17beta-estradiol and 17alpha-estradiol on adult human omental adipocyte precursors grown in a propagating culture system was studied . Cells were grown in subculture in the presence or absence of hormone . 17beta-estradiol resulted in significant promotion of adipocyte precursor replication, as determined by cell counting and incorporation of radioactive thymidine into DNA . The hormone stimulated cell multiplication in the concentration range 0.5--500 ng/ml growth medium . The highest level tested was 500 ng/ml . The maximal effects were obtained at 50 ng/ml (P less than 0.001 by paired t test, 48 h after hormone addition) . All 10 cell strains (five were derived from men and five from women) that were tested responded similarly to the hormone . 17beta-estradiol did not affect cell size . 17alpha-estradiol did not promote the replication of adipocyte precursors, nor did it influence cell size . Thus, 17beta-estradiol, which is the active isomer in known target tissues, stimulates the multiplication of human adipocyte precursors in culture.

Cancer Res, 1978 Sep, 38(9), 2773 - 6
Lactate dehydrogenase in estrogen-responsive human breast cancer cells; Burke RE et al.; Lactate dehydrogenase activity (LDH) was measured in the MCF-7 human breast cancer cell line derived at the Michigan Cancer Foundation from a patient with metastatic breast adenocarcinoma . LDH was found in the 46,000 X g supernatant of cell lysates, but not in the culture medium . Only the fifth isozyme (LDH-5) could be demonstrated by cellulose acetate electrophoresis and relative heat inactivation studies . When endogenous steroids were removed from the medium, addition of estrogen to the growth medium for several days elevated LDH 2-fold above controls; LDH was not altered when MCF-7 cells were treated with progesterone, hydrocortisone, prolactin, insulin, or triiodothyronine . A physiological concentration (0.1 nM) of 17beta-estradiol was sufficient to produce a maximal LDH increase . There were no qualitative isozyme changes in response to estrogen . LDH activity may therefore be a useful marker protein for studying hormone action in the MCF-7 human breast cancer cell line.

J Dent Res, 1978 Sep-Oct, 57(9-10), 928 - 31
The effect of NaF on the bacterial production of polysaccharide and subsequent adsorption on hydroxyapatite; Shimura N et al.; The affinity of some bacterial polysaccharides for hydroxyapatite was investigated . Water insoluble polysaccharide production by bacteria was inhibited by the presence of NaF in the growth medium, while the water soluble fraction was unaffected . The adsorption of the bacterial polysaccharide on hydroxyapatite decreased with decreasing levels of the water insoluble fraction . It is suggested that NaF can inhibit bacterial attachment and caries by interfering with bacterial attachment through reducing the production of water insoluble polysaccharide.

Mikrobiologiia, 1978 Sep-Oct, 47(5), 805 - 9
{Gas chromatographic study of broth cultures of microorganisms as a method of detecting extraterrestrial life}; Imshenetskii AA et al.; The method of pyrolysis--gas chromatography was used to study the composition of cultural liquids obtained upon the incubation of desert soil samples in a rich growth medium . The composition of pyrolysis products was found to depend on the time of incubation . Cultural liquids differed in their composition from the original growth medium . This method is a dynamical one, and can be employed to control the activity of microorganisms.

J Cell Physiol, 1978 Sep, 96(3), 361 - 9
Effects of acidified fetal bovine serum on the fibrinolytic activity and growth of cells in culture; Loskutoff DJ; The fibrinolytic activity of cells in culture varied with the type of serum employed in the growth medium . Degradation of iodinated fibrin occurred slowly when Rous sarcoma virus-transformed chick embryo fibroblasts were grown in medium containing fetal bovine serum (FBS), and rapidly when chicken serum was employed . This difference reflected the low plasminogen and high inhibitor content of FBS . The inhibitors were found to be serum macromolecules that were precipitated with ammonium sulfate or polyethylene glycol, and were inactivated by boiling or upon exposure to acidic conditions . No inhibitor activity was detected in fetuin, one of the major proteins present in FBS . Acidified FBS was similar to chicken serum in that both supported high rates of cell-mediated fibrinolytic activity . Although virally transformed hamster, mouse and chicken cells grew well in acid-treated FBS, their normal counterparts did not . Apparently, acifification resulted in the formation of materials that were toxic to normal cells . These agents rapidly blocked cellular DNA synthesis.

Calcif Tissue Res, 1978 Aug 18, 25(3), 255 - 63
Fetal rat bone in organ culture: effect of bone growth and bone atrophy on the comparative losses of 45Ca and 3H-tetracycline; Chen TL et al.; Fetal rat bones were cultured in either growth-inducing or resorption-inducing media to study mineral losses during bone growth and atrophy in vitro . Whole radii and ulnae from 19-day-old fetal rats, prelabeled with 45Ca and/or 3H-tetracycline, were cultured intact or cut, and then digested by collagenase to obtain the calcified portion of the bones . Three- to five-fold more 3H-tetracycline than 45Ca was lost from the calcified portion when the bones were cultured for 4 days in growth-inducing media . Similar small amounts of 45Ca were lost from live and killed bones, but more 3H-tetracycline was lost from live bones than from killed bones . More 3H-tetracycline was released into the growth medium with a low concentration of calcium (0.5 mM) than when the calcium concentration was high (1.0 mM); no significant difference was seen in the release of 45Ca into the medium at different calcium concentrations . Larger amounts of both isotopes were lost when the prelabeled bones were cultured in resorption-inducing media than in growth-inducing media . When parathyroid hormone stimulated bone resorption in a resorption-inducing medium, equal proportions of both isotopes and bone collagen were lost . Greater losses of 3H-tetracycline than of 45Ca suggest that 45Ca was conserved locally during the resorption that accompanies bone growth, but not during resorption that accompanies bone atrophy.

J Bacteriol, 1978 Aug, 135(2), 483 - 9
Differences in incorporation of nucleic acid bases and nucleosides by various Mycoplasma and Acholeplasma species; McIvor RS et al.; Eight species representative of the serological diversity of the Mycoplasmatales were tested for their ability to incorporate radiolabeled nucleic acid precursors into acid-insoluble material . Cultures in complex growth medium were centrifuged and resuspended in minimal essential medium (Eagle) . For Acholeplasma laidlawii, labeling occurred mainly during the first 4 h of incubation, with substrate saturation at 20 micron . All organisms tested incorporated uracil, adenine, and guanine; none incorporated cytosine . Thymine was incorporated only by bovine group 7, Mycoplasma putrefaciens, and Mycoplasma pneumoniae (strain 3546), but deoxynucleosides enhanced thymine incorporation in A . laidlawii, Mycoplasma gallisepticum, M . pneumoniae (strain AP-164), and Mycoplasma hyorhinis . Nucleoside incorporation (adenosine, guanosine, uridine, cytidine, and thymidine) was not observed for the arginine-utilizing species, Mycoplasma hominis and Mycoplasma arginini, whereas all other organisms tested incorporated nucleosides . The incorporation pattern provides additional metabolic evidence to support the biochemical and antigenic diversity of these organisms . The recognition of differences in incorporation of nucleic acid precursors is important not only to the specific labeling of these organisms, but also to the study of metabolism and transport.

Cancer Res, 1978 Aug, 38(8), 2378 - 84
Folate and pterin metabolism by cancer cells in culture; Stea B et al.; Malignant cells grown in culture excrete into their growth medium a folate catabolite that can be seen as a blue-fluorescent region on paper chromatograms of such media . This folate catabolite has now been identified by paper chromatography, thin-layer chromatography, and combined gas chromatography-mass spectrometry as 6- hydroxymethylpterin and not as pterin-6-carboxaldehyde as previously reported . Moreover, when pterin-6-carboxaldehyde was added to the growth medium of logarithmically growing malignant cells, it was primarily reduced to 6-hydroxymethylpterin . In contrast pterin-6-carboxylate was the principal product formed from added pterin-6-carboxaldehyde by normal established cell lines in culture . These results have been interpreted as indicative of a possible mechanism of folate catabolism in malignant cells . Folic acid or another folate derivative is oxidatively cleaved at the C-9-N-10 bond to yield pterin-6-carboxaldehyde as one of the products . This derivative is subsequently reduced to 6-hydroxymethylpterin, which is excreted into the growth medium.

Cytobiologie, 1978 Aug, 17(2), 421 - 32
Localization of concanavalin A binding sites on the cell membrane of Herpetomonas samuelpessoai: influence of growth conditions; Sixel JL et al.; Herpetomonas samuelpessoai agglutinates when incubated with concanavalin A (Con A) . Agglutination involved binding of Con A to specific receptors as it was inhibited by alpha-methyl-D-mannoside . The pattern and the intensity of the agglutination as well as the localization of Con A-binding sites were influenced by the composition of the growth medium, growth temperature and time of incubation . Con A-binding sites were detected by using the Con A-horseradish peroxidase-diaminobenzidine technique.

Biull Eksp Biol Med, 1978 Aug, 86(8), 235 - 8
{Insulin-forming activity of monolayer cultures of pancreatic islet cells from cattle fetuses}; Fedotov VP et al.; The radioimmunological method was applied to the study of insulin content in the growth medium of primary monolayer cultures of bovine fetal pancreatic islet cells grown with usual and increased (300 mg%) glucose content . The latter led to an enhanced insulin secretion . The results of cytological study demonstrated a definite interrelationship between the mitotic activity of culture cells and the intensity of insulin secretion into the medium.

Mikrobiologiia, 1978 Jul-Aug, 47(4), 675 - 81
{Effect of exogenous acetyl group acceptors on cholinesterase biosynthesis in Arthrobacter simplex cells}; Imshenetskii AA et al.; The presence of active acetyl or butyryl groups and their acceptors in the growth medium was found to be necessary for the high rate of cholinesterase biosynthesis in the cells of Arthrobacter simplex var . cholinesterasus . The active acetyl and butyryl groups are formed upon hydrolysis of acetylcholine and butyrylcholine as well as in the course of glucose metabolism . The following acids were shown to be the acceptors of the acetyl and butyryl groups: butyric, succinic, fumaric, malic acids and, to a less extent, alpha-ketoglutaric acid . The active acetyl and butyryl groups are bound with the acceptors under the control of coenzyme A in the reactions of fatty acid synthesis and the tricarboxylic acid cycle . Presumably, CoA regulates cholinesterase synthesis . The high rate of CoA binding in metabolic reactions provides conditions for the intensive synthesis of cholinesterase; the deceleration of these reactions inhibits the biosynthesis of cholinesterase.

Mikrobiologiia, 1978 Jul-Aug, 47(4), 672 - 4
{Effect of various nitrogen sources on lipase formation by Rhizopus microsporus}; Zubenko TF et al.; The effect of organic and mineral nitrogen sources on the production of lipolytic enzymes and the accumulation of biomass was studied with Rhizopus microsporus UzLT-I . Addition of mineral nitrogen sources to the growth medium weakly stimulated synthesis of lipase by the fungus . The production of lipolytic enzymes was highest on media with organic nitrogen compounds, particularly yeast autolysate and fodder yeast cells (0.1: 0.25%) . The lipolytic activity of the cultural broth on media with these nitrogen sources increased by 50% cf . the control.

Mikrobiologiia, 1978 Jul-Aug, 47(4), 722 - 7
{Production of mutants with an increased alpha-amylase synthesis}; Ostrikova NA et al.; A mutant characterized by elevated biosynthesis of alpha-amylase was obtained as a result of a three-stage induced selection using nitroso compounds . Changes of mutagens in the course of selection stages and the establishment of their effective doses causing the maximum accumulation of mutations yielded the mutant which produced 2.5 times more alpha-amylase than the parent strain of Aspergillus oryzae 762 . The induced variability of the mutant can be registered on a solid growth medium and provides the high activity of alpha-amylase.

Arch Microbiol, 1978 Jul, 118(1), 1 - 6
Arginine catabolism in Aphanocapsa 6308; Weathers PJ et al.; The catabolic products of arginine metabolism were observed in Aphanocapsa 6308, a unicellular cyanobacterium, by thin layer chromatography of growth media, by limiting growth conditions, and by enzymatic analysis . Of the organic, nitrogenous compounds examined, only arginine supported growth in CO2-free media . The excretion of ornithine at a concentration level greater than citrulline suggested the existence in Aphanocapsa 6308 of the arginine dihydrolase pathway which produced ornithine, CO2,NH4,+ adenosine 5'-triphosphate . Its existence was confirmed by enzymatic analysis . Although cells could not grow on urea as a sole carbon source a very active urease and subsequently an arginase were also demonstrated, indicating that Aphanocapsa can metabolize arginine via the arginase pathway . The level of enzymes for both pathways indicates a lack of genetic control . It is suggested that the arginase pathway provides only nitrogen for the cells wheras the arginine dihydrolase pathway provides not only nitrogen, but also CO2 and adenosine 5'-triphosphate.

J Neurol, 1978 Jun 16, 218(3), 149 - 56
Muscular carnitine synthesis and palmitate metabolism in vitro; Scarlato G et al.; The carnitine content of the culture media for normal and pathological human muscles, including a case of systemic carnitine deficiency (SCD) was measured and the carnitine concentration was the same in all normal and pathological muscle culture media . Carnitine was never detected in growth medium . Some fibroblasts and myoblasts were filled with neutral lipids in SCD . 14C-palmitate added to the medium was incorporated by SCD fibroblasts or myoblasts to the same concentration as in normal or pathological cells . Factors other than carnitine seem to account for the lipid accumulation of SCD in cell culture.

Mol Gen Genet, 1978 Jun 14, 162(2), 139 - 49
Disturbance of the machinery for the gene expression by acidic pH in the repressible acid phosphatase system of Saccharomyces cerevisiae; Toh-e A et al.; When the pH of growth medium containing a limited amount of inorganic phosphate is kept below 3.0, cells of Saccharomyces cerevisiae produce repressible alkaline phosphatase but no repressible acid phosphatase . The same cells produce acid phosphatase immediately on shifting the medium pH to 4.0 or above . Like intact cells, spheroplasts prepared from cells grown at pH 3.0 or 4.5 in medium with a limited amount of inorganic phosphate in suspension begin production of acid phosphatase immediately after pH shift from below 3.0 to 4.0 whereas sheroplasts from cells grown in inorganic phosphate-rich medium showed a prolonged lag period (3 h) . The enzyme formation on the pH shift was sensitive to cycloheximide . No significant differences could be detected in cellular growth or in incorporation of 3H-L-lysine or 14C-adenine between cells cultivated at pH 3.0 and 4.5 . These results along with the fact that the expression of structural genes of repressible acid and alkaline phosphatases is controlled by a common genetic regulatory system, at least in part, indicate that the genetic regulatory system operates to express the structural genes even at low pH, though the expression of repressible acid phosphatase is interrupted . Coupled experiments of temperature and pH shifts with the temperature-sensitive mutants of the regulatory genes suggest that the acidic pH affects the function of the cytoplasmic products of those genes in the expression of the structural gene . Based on these observations, a revised model involving the simultaneous functioning of the regulatory factors was suggested for the genetic regulation of repressible acid phosphatase synthesis.

J Physiol, 1978 Jun, 279, 187 - 96
Fever and survival: the role of serum iron; Grieger TA et al.; 1 . The effects of bacterial infection and temperature on serum iron levels were investigated in the lizard Dipsosaurus dorsalis . 2 . Changes in body temperature from normal (38 degrees C) to febrile (41 degrees C) did not alter serum iron levels . Injection with Aeromonas hydrophila led to a significant reduction in serum iron levels, comparable to that found in mammals . This reduction in serum iron level was independent of the lizard's body temperature . 3 . When grown in vitro, A . hydrophila grew equally well at afebrile (38 degrees C) and febrile (41 degrees C) temperatures . When the iron levels of the growth medium were reduced, the bacterial growth was diminished at the febrile temperature but was not significantly affected at the afebrile temperature . 4 . The addition of iron supplements to bacterially infected lizards led to an increase in the percent mortality . 5 . These results indicate that one of the mechanisms behind the beneficial, or adaptive value of fever in D . dorsalis is the decrease in iron available to the pathogenic micro-organisms.

Can J Biochem, 1978 Jun, 56(6), 462 - 9
Lipid compositional manipulation in Acholeplasma laidlawii B . Effect of exogenous fatty acids on fatty acid composition and cell growth when endogenous fatty acid production is inhibited; Silvius JR et al.; A variety of potential inhibitors of de novo fatty acid biosynthesis have been tested for activity in Acholeplasma laidlawii B . Two compounds, avidin and N,N-dimethyl-4-oxo-2trans-dodecenamide (CM-55), an antimicrobial fatty amide, strongly inhibit de novo biosynthesis without nonspecific toxic effects at moderate dosages . Avidin is the more potent inhibitor, abolishing de novo fatty acid synthesis and greatly reducing the chain elongation of exogenous fatty acids at level of 25 U/l . CM-55 gives complete inhibition of de novo biosynthesis only at low temperatures and inhibits exogenous fatty acid elongation to a variable extent . However, CM-55 is still a more potent antilipogenic agent in this organism than is the fungal antibiotic cerulenin . Cells cultured with avidin grow only when one or more exogenous medium- or long-chain fatty acids are added to the growth medium . The extent of cell growth under these conditions depends primarily on the physical properties of the exogenous fatty acid(s) . In general, fatty acids giving diacylglycerolipids of very high or very low fluidity are unsuitable growth substrates, while those whose diacylglycerol derivatives are of intermediate fluidity support fair to good cell growth.

Invest Ophthalmol Vis Sci, 1978 Jun, 17(6), 523 - 7
Synthesis of glycosaminoglycans by cultures of normal human corneal endothelial and stromal cells; Yue BY et al.; Monolayer cultures of normal human corneal endothelial and stromal cells were incubated with {35S}sulfate and {3H}glucosamine for 4 hr . The labeled glycosaminoglycans resulted from this incubation were isolated from the cell layer and the growth medium and further characterized . Both endothelial and stromal cell cultures synthesized a variety of sulfated glycosaminoglycans, with chondroitin 6-sulfate as the major product . Chondroitin 4-sulfate, dermatan sulfate, and heparan sulfate were present in smaller amounts . Keratan sulfate was produced only in minimal amounts . Both cell types also synthesized hyaluronic acid . The hyaluronic acid production in stromal cell strains derived from donors of different ages was similar . The demonstration that the endothelial cell strain derived from a 1-day-old baby contained more hyaluronic acid than cultures from older donors suggests a possible age-related phenomenon as seen in developing tissues.

Appl Environ Microbiol, 1978 Jun, 35(6), 1116 - 20
Reversal of the silver inhibition of microorganisms by agar; Tilton RC et al.; Increasing use of silver in the treatment of water has necessitated an examination of microbiological methods for the measurement of silver inactivation of microorganisms . Three common agar media were tested for their ability to neutralize the bacteriostatic effects of silver . Results suggested that growth media differed in their neutralizing capacity; that is, the non-inhibitory media tryptone glucose agar and Trypticase soy agar showed more neutralizing capacity than eosin methylene blue agar . Furthermore, the neutralizing effect appeared to be a function of the soluble component of the media and not of the agar itself.

Br J Cancer Suppl, 1978 Jun, 37(3), 54 - 9
Cytotoxicity of misonidazole and DNA damage in hypoxic mammalian cells; Palcic B et al.; The loss of colony-forming ability and the yield of DNA single strand breaks were studied following exposure of various mammalian cell types to misonidazole . A correlation was observed between cell inactivation and DNA damage . If, after exposure, the cells were washed free of the drug and then incubated at 37 degree C in growth medium, it was observed that surviving cells repaired their DNA to the point that sedimentation profiles were identical to those of unexposed cells . In nonsurviving cells, however, the DNA was found to be further degraded with post-exposure incubation.

Int J Radiat Biol Relat Stud Phys Chem Med, 1978 Jun, 33(6), 577 - 85
Inhibition of x-ray-induced protection of Escherichia coli K-12 cells against the lethal effects of ultra-violet light by nitrofurantoin; Martignoni KD; Wild-type cells of E . coli K-12 showed increasing U.V . resistance if they were X-irradiated and incubated at 37 degrees C in growth medium before the U.V . exposure . Development of higher U.V . resistance could be inhibited by incubating the X-irradiated cells either at temperatures below 15 degrees C, or in the presence of 0.01 M KCN . Nitrofurantoin (NF), which was recently found specifically to inhibit inducible enzyme synthesis, had only a transient inhibitory effect on X-ray-induced U.V . resistance . Cells grown in glucose medium showed less inhibition by NF of X-radiation-induced resistance to U.V.-radiation than did cells grown in glycerol, or in glucose medium with added cyclic AMP . It is suggested that X-ray-induced U.V . resistance requires active cellular metabolism, but it is not subject to catabolite repression . The following hypothesis is offered to explain the action of NF: Under de-repressed conditions (without catabolite repression by glucose) nitrofurantoin could counteract the radiation-induced inhibition of a repair inhibitor (such as post-irradiation DNA degradation).

Genetics, 1978 Jun, 89(2), 271 - 9
An apparent connection between histidine, recombination, and repair in Neurospora; Newmeyer D et al.; Two mutants of Neurospora crassa, uvs-3 and mei-3, share four properties--UV sensitivity, inhibition by histidine, meiotic blockage when homozygous, and increased duplication instability (due to mitotic crossing over, to deletions or to both) . The present paper shows that a third nonallelic mutant, uvs-6, exhibits the same four properties.--Also, the instability of duplications in the absence of any UV-sensitive mutant is increased by the presence of histidine in the growth medium.

Biomedicine, 1978 Jun, 29(4), 143 - 6
Search for endogenous C-type viruses in cultures of non leukemic human cells; Bernard C et al.; Cultures of cells derived from non-leukemic human tissues were submitted to treatments known to induce endogenous C-type viruses of a number of animal species . Virus expression was evaluated by reverse transcriptase (RT) assays in the growth medium . Of 20 cultures treated or untreated with bromodeoxyuridine, 18 were totally negative in RT assays . Of the 2 positive cultures, one was a human-mouse hybrid in which the induction of RT activity coincided with the expression of murine antigens . The other culture, a diploid strain which exhibited borderline enzymatic activity, was subjected to more detailed analysis after treatment with several chemical inducers and/or irradiation, but none of these procedures gave clearly positive results . The apparent lack of an endogenous virus synthesis in these human cells is discussed.

Biochim Biophys Acta, 1978 May 25, 529(2), 359 - 64
Very low density lipoprotein stimulation of triglyceride accumulation in rat preadipocyte cultures; de la Llera M et al.; Exposure of cultured rat epididymal preadipocytes to human very low density lipoproteins (VLDL) resulted in the rapid accumulation of large amounts of cellular triglyceride which was accompanied by the appearance of numerous large cellular lipid inclusions . Addition of heparin produced a two-fold stimulation of lipoprotein induced triglyceride accumulation . Supplementation of the growth medium with either low density lipoprotein, oleic acid or artificial triglyceride emulsion did not produce cellular triglyceride levels equivalent to that obtained with VLDL . Fibroblastic cells from rat skin and lung did not accumulate triglycerides when exposed to VLDL and heparin.

Biochim Biophys Acta, 1978 May 24, 534(1), 7 - 14
The state of copper in Neurospora laccase; Lerch K et al.; 1 . Neurospora crassa laccase has been prepared from the growth medium and studied by optical absorption, circular dichroism and electron paramagnetic resonance (EPR) spectroscopy . The molecular weight, the copper content and the amino acid composition have also been determined . 2 . The molecular weight as determined by gel filtration in 6 M guanidine hydrochloride and by sodium dodecyl sulfate gel electrophoresis is found to be 64 000 . The enzyme contains 3.8 copper ions per 64 000 . 3 . The visible and the near ultraviolet difference absorption spectrum shows two maxima, at 330 and 595 nm, and a shoulder at about 720 nm . The circular dichroism spectrum between 300 and 760 nm contains five bands in the oxidized enzyme . After reduction of the enzyme with ascorbate there remains only a band at 305 nm . 4 . EPR measurements show that 52% of the total copper in the protein is paramagnetic . Two EPR signals of equal intensity with different hyperfine splitting constants, of 9 and 18.5 mT, are present, which are assigned to Type 1 Cu2+ and Type 2 Cu2+, respectively, as found in other blue copper-containing oxidases.

Cell Tissue Res, 1978 May 18, 189(1), 31 - 40
Separation and maturation of gonadotrophs from 2A8 clonal cells in vitro; Ishikawa H et al.; 2A8 clonal cells derived from the epithlium of Rathke's pouch of fetal rats were cultured in growth medium supplemented with fresh rat serum, median-eminence extract and 1-thyroxine . Then, in order to isolate gonadotrophs, cyanogen bromide-activated Sepharose whichwas conjugated with LHRH (LHRH-Sepharose) was added to the culture medium . Fourteen days after incubation of 2A8 cells with LHRH-Sepharose, agranular and granular cells were rapidly bound to LHRH-Sepharose when fresh serum had previously been added in the medium . The cytoplasm of granular cells that were bound to LHRH-Sepharose contained spherical secretory granules (200-250 nm in diameter) . These cells were similar in morphology to the FSH and LH gonadotrophs described by Kurosumi (1968) . Moreover, many of them appeared as hypertrophied cells that resembled "castration" cells . These results demonstrate that LHRH conjugated to Sepharose can be used to separate gonadotrophs from other 2A8 cells, and it is suggested that the hypertrophy of some cells might be due to persistent stimulation by LHRH which is likely bound to receptors on the cell membrane.

Muscle Nerve, 1978 May-Jun, 1(3), 219 - 29
Actin-containing microprocesses in the fusion of cultured chick myoblasts; Huang HL et al.; Scanning electron microscopic studies of myoblasts from 11- to 13-day-old chick embroyonic breast muscle cultured on collagen-coated glass coverslips showed six stages of development into multinucleated myotubes: (1) growth of flattened, spread-out cells for 20-30 hr following initiation of monolayer cultures; (2) extension of microprocesses (1-150 microM) from cells that have become spindle shaped; (3) contact and adherence of microprocesses from adjacent cells; (4) thickening of fused processes; (5) approximation of the cells; and (6) coalescence of the cells to form a spindle-shaped myotube . When the calcium-ion concentration in the growth medium was lowered--either by increasing the concentration of ethylene-glycol-bis(aminoethyl ether)N,N'-tetraacetate (EGTA)or by decreasing the cconcentration of free calciumion used--the number of microprocesses present on the cells was reduced . Presumably, however, these microprocesses could still fuse together, provided that the calciumion concentration was greater than 160 microM . Indirect immunofluorescence assay with actin-specific antibody indicated that actin is a major component of the myoblasts' microprocesses . Cytochalasin B (5 microgram/ml) caused the microprocesses to retract within 15 min and the myoblasts to round up and detach from the glass substrate . This was presumably caused by the action of the drug on actin filaments.

Mikrobiologiia, 1978 May-Jun, 47(3), 430 - 5
{Effect of glutamic acid on Saccharomyces cerevisiae cell permeability during rehydration after dehydration}; Ramnietse VE et al.; Losses of potassium ions, nucleotides and protein substances were studied upon rehydration of Saccharomyces cerevisiae cells grown on a defined nutrient medium with ethanol and glutamic acid (0.075%) and subjected to dehydration . Considerable amounts of K+ (75--82% of the total), nucleotides and protein substances were found to be released into distilled water upon rehydration of the dehydrated yeast cells . If a higher percentage of yeast cells survived, these lost less nucleotides and nitrogen-containing substances . Glutamic acid being added to the growth medium did not decrease specifically the permeability of the dehydrated yeast cells upon rehydration.

J Bacteriol, 1978 May, 134(2), 394 - 400
Repression of Escherichia coli pyridine nucleotide transhydrogenase by leucine; Gerolimatos B et al.; Addition of 0.1% casein hydrolysate to a minimal growth medium decreased membrane-bound transhydrogenase activity in Escherichia coli by about 80% . Of the amino acids added individually to the growth medium, only leucine and, to a lesser extent, methionine and alanine were effective, alpha-Ketoisocaproate- and leucine-containing peptides repressed the activity, and leucine also repressed activity in adenyl cyclase-deficient and relaxed strains . Derepression of transhydrogenase followed the removal of leucine from the growth medium and was sensitive to rifampin and chloramphenicol . A phosphoglucoisomerase-deficient strain that was forced to use the hexose monophosphate shunt exclusively had normal levels of transhydrogenase, which was repressed by leucine . Transhydrogenase activity doubled in mutants lacking either of the shunt dehydrogenases but was still repressed by leucine . In strains constitutive for the leucine biosynthetic operon, transhydrogenase was repressed by leucine but in strains livR and lst R, with leucine transport resistant to leucine repression, transhydrogenase was not repressed by leucine . These data suggest that transhydrogenase may have a function in the transport of branched-chain amino acids . In a hisT strain (which has altered leucyl-tRNA), transhydrogeanse was at a repressed level without the addition of leucine, suggesting that leucyl-tRNA may be involved in the regulation.

Mutat Res, 1978 May, 50(2), 181 - 93
Biochemical analysis of damage induced in yeast by formaldehyde . I . Induction of single-strand breaks in DNA and their repair; Magana-Schwencke N et al.; Analysis of sedimentation profiles in alkaline sucrose gradients showed that, through a metabolic process, formaldehyde (FA) produced single-strand breaks in DNA of exponential phase cells of haploid wild-type Saccharomyces cerevisiae . The production of this type of lesion was dose-dependent . Strains defective in excision-repair of pyrimidine dimers induced by ultraviolet (UV) irradiation showed a reduced capacity to undergo single-stand breaks after treatment with FA . This indicates that the repair pathways of damage induced by UV and FA share a common step . Post-treatment incubation of wild-type cells in growth medium indicate a lag in cell division during which a slow recovery of DNA with a normal size was observed.

J Natl Cancer Inst, 1978 May, 60(5), 1035 - 41
Characterization of the inhibitory effects of retinoids on the in vitro growth of two malignant murine melanomas; Lotan R et al.; The in vitro proliferation of murine melanoma cell lines S91 and B16 was inhibited by retinoic acid and retinyl acetate . The inhibitory effects were dependent on retinoid concentration and increased from 55 and 30% at 10(-9) M retinoic acid to 85 and 82% at 10(-5) M retinoic acid for S91 and B16 melanoma cells, respectively . S91 melanoma cells were more sensitive than B16 melanoma cells to inhibition by either retinoid, and both cell lines were more sensitive to retinoic acid than to retinyl acetate . When exposed to 10(-5) M retinoic acid, the two cell types grew at the same rate as did control cells for 48 hours, whereupon the growth rates of retinoid-treated cells decreased . After 6 days, the number of cells in control cultures increased 140 times (S91 melanoma cells) and 265 times (B16 melanoma cells), whereas retinoic acid-treated cells increased only 14 times (S91 melanoma cells) and 40 times (B16 melanoma cells) . The degree of growth inhibition by retinoic acid was not dependent on initial cell density . Cortisone and hydrocortisone failed to prevent or reduce the inhibitory effect of retinoic acid; the release of lysosomal acid phosphatase was not increased and the intracellular level of 3',5'-cyclic AMP in cells grown for 5 days in the presence of 10(-5) M retinoic acid was not elevated . Viability of S91 and B16 cells after 8 days' exposure to 10(-5) M retinoic acid was similar to that in control cultures . The reduced growth rate of retinoic acid-treated cells reversed to the control rate 48-72 hours after removal of retinoic acid from the growth medium.

Mikrobiologiia, 1978 May-Jun, 47(3), 403 - 8
{Acetic acid, a catabolite repressor of cholinesterase synthesis by an Arthrobacter simplex culture}; Imshenetskii AA et al.; Acetic acid was found to repress cholinesterase synthesis in the cells of Arthrobacter simplex var . cholinesterasus even at very low concentrations (0.1%) . The repression is very stable . It is not eliminated by glucose or an organic acid of the Krebs cycle being added to the medium with acetic acid . The combination of acetic and butyric acids decreases the repression but does not eliminate it . The kinetics of cholinesterase synthesis was different in the cells grown on the medium with acetic acid and the cells cultivated on the medium with acetic acid and glucose, then washed and transferred to a fresh growth medium with glucose and acetylcholine as the sources of carbon.

Infect Immun, 1978 May, 20(2), 352 - 9
Heat-stable enterotoxin from Escherichia coli: factors involved in growth and toxin production; Johnson WM et al.; Six enterotoxigenic strains of Escherichia coli produced variable levels of heat-stable enterotoxin (ST) when grown under pH control at 8.5 in a simple synthetic medium containing neither amino acids nor vitamins . Bacterial growth and ST production were at levels as high as or higher than those observed in complex media . ST elaboration was detectable in the early logarithmic phase of growth and appeared to be related to disappearance of glucose in the growth medium . The results of this study did not suggest pH-dependent release of ST . Imposition of pH control in complex media resulted in increased growth rates, earlier detectable ST synthesis, and elevated levels of ST . In synthetic medium, attainment of the stationary growth phase was followed by a significant decrease in culture density and a concomitant increase in ST . Cellular autolysis experiments revealed that as much as 20% of the total ST activity was present in a cell-associated form.

Endocrinology, 1978 Apr, 102(4), 1155 - 66
Effect of glucagon and insulin on the growth of neonatal rat hepatocytes in primary tissue culture; Armato U et al.; Commercial (bovine-porcine) glucagon added in a single dose between 10(-12) and 10(-7) M to neonatal rat hepatocytes in primary cultures with subsequent incubation for 20-24 h, stimulated their entry into the DNA synthesis phase as revealed by {3H}thymidine-labeling and radioautography; about 14 h of incubation was required before an effect was observed . Commercial (bovine) insulin at doses between 10(-11) and 10(-7) M apparently stimulated the entry of hepatocytes into S phase . However, insulin's effect, which needed 20 h for induction, was due to the release of a wave of synchronized hepatocytes from an earlier produced block near the G1/S boundary of their growth-division cycle . Equimolar mixtures of glucagon with insulin from 10(-15)-10(-7) M increased the fraction of hepatocytes synthesizing DNA first at 4-8 h, and then at 20-24 h . Effective doses of glucagon, insulin, and glucagon plus insulin also increased the entry of hepatocytes into mitosis, as found after a 4-h incubation with colchicine (0.1 mM) . Withholding inactivated fetal bovine serum from the growth medium for 24 h did not change the mitotic activity either of the untreated or of the glucagon- and glucagon plus insulin-stimulated hepatocytes, but it increased the proliferogenic effect of bovine insulin . Highly purified crystalline (porcine) glucagon, insulin, and glucagon plus insulin also stimulated the growth of hepatocytes in the presence or absence of serum . Finally, equimolar (10(-14) M) mixtures of glucagon with (Bu)2cGMP and of insulin with (Bu)2cAMP increased the hepatocytic replication as efficiently as did glucagon plus insulin at the same dose . The present results show that glucagon and insulin are synergistic, intracycle regulators of the growth of neonatal rat hepatocytes . They also suggest that cyclic necleotides may mediate at least partly the hepatotropic effects of the pancreatic hormones.

J Cell Physiol, 1978 Apr, 95(1), 33 - 40
Density-dependent effects of oxygen on the growth of mammalian fibroblasts in culture; Taylor WG et al.; Various concentrations of oxygen were used to determine the optimum culture medium PO2 for survival and proliferation of attached human and mouse fibroblasts grown from different inoculum sizes . When T-15 flasks were seeded with less than or equal to 2 X 10(4) cells (less than or equal to 1.3 X 10(3) cells/cm2), the highest plating efficiencies and cell yields were obtained with a culture medium PO2 of 40-60 mm Hg . At higher inoculum sizes (10(5) cells per T-15) used routinely for mass cultured, no difference in cell yield or glycolytic activity was observed between cultures gassed with atmospheric, i.e., 18% O2 (growth medium PO2 approximately equal to 125-135 mm Hg) and those gassed with 1% O2 (growth medium PO2 approximately euqal to 40-60 mm Hg) . The enhanced clonal growth observed at the latter PO2 results from an increased proliferation rate rather than more efficient attachment and survival of inoculated cells . Glucose uptake and lactic acid accumulation were increased in sparse cultures sparged with 1% O2 . A slight extension of lifespan was observed in WI-38 cells serially subcultured with a gas phase of 1% O2.

Mol Cell Endocrinol, 1978 Apr, 10(2), 163 - 73
Cyclic and temporal differences in LH-RH-stimulated LH release in cultured rat pituitary cells; Reel JR et al.; To establish whether the enhanced LH-RH responsiveness shown by pituitary gonadotrophs at proestrus in vivo could be maintained in vitro, rat anterior pituitary cells were investigated to determine differences in LH release in response to LH-RH through the estrous cycle and with time in primary culture . Pooled or individual anterior pituitary glands from each day of the cycle were dissociated with collagenase, hyaluronidase and Viokase and cultured for from 1 to 4 days . Four-day cultures of proestrous cells did not show differences in LH-RH responsiveness when compared to estrous, diestrous I and diestrous II cells . In addition, proestrous cells did not show differences in LH-RH responsiveness when compared to diestrous II cells after 1, 2, 3 or 4 days of culture; however, over the same 1--4 days of culture, proestrous cells contained higher amounts of LH and released greater quantities of LH into the growth medium than did diestrous II cells . It was also observed that both proestrous and diestrous II cells exhibited significantly greater LH-RH responsiveness after 3 or 4 days of culture than after 1--2 days of culture . These results suggest that the differential LH-RH responsiveness shown by pituitary gonadotrophs at proestrus in vivo is not maintained when pituitary cells are placed in primary culture.

J Bacteriol, 1978 Apr, 134(1), 246 - 60
Ribonucleoprotein particle appearing during sporulation in yeast; Wejksnora PJ et al.; During sporulation of Saccharomyces cerevisiae, most strains accumulate an unmethylated 20S RNA . Contrary to previous reports, this sporulation 20S RNA is distinct from the short-lived methylated 20S RNA precursor of 18S rRNA . This RNA species was found in a cytoplasmic 32S ribonucleoprotein particle consisting of one single-stranded 20S RNA molecule and 18 to 20 identical protein subunits of molecular weight 23,000 . The ribonucleoprotein particle was resistant to ribonuclease digestion, although purified 20S RNA was ribonuclease sensitive . Both the RNA and the protein of the 32S ribonucleoprotein particle were only synthesized under conditions that induce sporulation . The accumulation of 20S RNA depended on continued protein synthesis but was actinomycin D insensitive, despite a high guanine-plus-cytosine content . Synthesis of 20S RNA stopped when cells were removed from sporulation conditions and placed in growth medium.

Arch Pathol Lab Med, 1978 Apr, 102(4), 165 - 71
Colony-stimulating activity; Hays EF et al.; Hemopoietic cells, when placed in single-cell suspension in a semisolid growth medium for seven to 14 days, have been found to form visible colonies of granulocytes and monocytes . Colony growth appears only in cultures to which a source of colony-stimulating activity (CSA) is added . Because of these in vitro effects, CSA is thought to be an in vivo regulator of granulocyte and monocyte production from progenitor cells in the bone marrow.

Biochim Biophys Acta, 1978 Mar 30, 528(3), 394 - 8
Control of phosphonic acid and phosphonolipid synthesis in Tetrahymena; Smith JD et al.; The phosphonolipid content of the protozoan Tetrahymena pyriformis was increased by growing the organism on a medium containing increasing amounts of 2-aminoethylphosphonic acid . With levels of 0, 1, 5 and 10 mM 2-amino-ethylphosphonic acid, the phosphonolipid content was 23, 25, 31 and 37% of the total cellular phospholipids, respectively . This increase was accompanied by a reciprocal decrease in phosphatidylethanolamine . With 32Pi in the growth medium along with the 2-aminoethylphosphonic acid, the incorporation of the radioactivity into new molecules of 2-aminoethylphosphonic acid was almost totally inhibited, indicating a feedback control on phosphonic acid synthesis.

Experientia, 1978 Mar 15, 34(3), 303 - 4
Effect of Tween 80 on lipids of Mycobacterium phlei ATCC 354; Dhariwal KR et al.; Addition of Tween 80 to the growth medium brings about qualitative and quantitative changes in the lipids of Mycobacterium phlei ATCC 354 . The results suggest that Tween 80 itself may be a variant in the system.

J Exp Med, 1978 Mar 1, 147(3), 745 - 57
Serine enzymes released by cultured neoplastic cells; Dano K et al.; Serine proteases or esterases released from cell cultures into the growth medium were converted to radioactive derivatives by active site labeling with tritiated DFP, both in the presence and absence of other competing active site reagents . The individual labeled enzymes were then identified by SDS-polyacrylamide gel electrophoresis and scintillation autoradiography . Conditioned medium from embryonal mouse fibroblasts transformed by mouse sarcoma virus contained five serine enzymes that were not present in medium from normal cells; two serine enzymes were released by both cell types, and one serine enzyme was found only in medium from normal cells . Two of the enzymes released by transformed cells were identified as plasminogen activators; these accounted for most of the serine enzyme labeling in transformed culture media and for most of the serine enzyme difference between normal and transformed cultures . The culture fluids from two cell strains of human neoplastic origin were examined by the same method . A rhabdomyosarcoma strain released eight serine enzymes (mol wt ranging from 22,500 to 102,000), four of which were plasminogen activators; seven serine enzymes (mol wt 26,000-102,000), including two plasminogen activators, were detected in medium from human melanoma cultures . In terms of electrophoretic mobility two of the plasminogen activators from rhabdomyosarcoma were identical with those from melanoma cultures, while the remaining two rhabdomyosarcoma activators coincided with activators found in commerical urokinase.

J Cell Physiol, 1978 Mar, 94(3), 287 - 98
Assay of ribonucleotide reduction in nucleotide-permeable hamster cells; Lewis WH et al.; Ribonucleotide reduction was measured in Chinese hamster ovary cells made permeable to nucleotides by treatment with the detergent Tween-80 . When compared to the respective ribonucleotide reductase activity in partially purified cell extracts, CDP and GDP reductase activities in permeabilized cells responded in a similar fashion to dithiothreitol, pH, MgCl2, FeCl3, substrate concentration and the presence of positive or negative allosteric effectors . At low protein concentrations both CDP and GDP reduction with whole cells increased linearly with cell number and was greater than the activity in corresponding cell extracts . Permeabilized cells were used to measure the level of CDP and GDP reductase in a hamster cell line resistant to the cytotoxic effects of hydroxyurea . The hydroxyurea-resistant cell line contained four to ten times more CDP and GDP reductase activity compared to parental or revertant cell lines . The permeabilized cell assay was also used to measure CDP and GDP reductase activities in Chinese hamster ovary cells synchronized by isoleucine starvation . CDP reductase activity was low in G1 arrested cells but increased 10-fold by 16 hours after the readdition of isoleucine to the growth medium . GDP reductase, which is present at much higher levels, is similarly induced after isoleucine addition, but only by 2-fold . The maximum activity of both CDP and GDP reductase occurred from 14 to 16 hours after isoleucine addition, which corresponded to the period of maximum DNA synthesis.

Mikrobiologiia, 1978 Mar-Apr, 47(2), 332 - 7
{Manganese concentration by microorganisms inhabiting the soils of a manganese biogeochemical province in Georgia}; Letunova SV et al.; The concentrating of manganese by microorganisms was studied with bacteria, actinomycetes and fungi inhabiting soils of the manganese biogeochemical province of the Georgian Republic with different content of this element (from 1045 to 296 000 mg/kg of dry weight) . The amount (from 4.0 X 10(-3) to 10 per cent per dry substance) and character of manganese accumulation by microorganisms were found to depend on the content of this element in the growth medium, the taxonomic position of microorganisms, and their adaptation to geochemical conditions.

Arch Microbiol, 1978 Mar, 116(3), 289 - 92
Effects of host aging, ions, and pH on the adsorption of the cyanovirus N-1 to Nostoc muscorum; Padhy RN et al.; The adsorption rate of the cyanovirus N-1 infecting the nitrogen-fixing blue-green alga Nostocmuscorum decreased with aging of algal cultures and the virus failed to adsorb to the dead host cells . The adsorption rate declined in saline magnesium chloride solution compared to that in algal growth medium . The addition of amino acids like L-tryptophan and L-phenylalanine failed to enhance the adsorption rate of the virus . Optimal pH of adsorption was 7.6 to 8;1.

J Cell Physiol, 1978 Mar, 94(3), 299 - 306
Toxicity, radiation sensitivity modification, and metabolic effects of dehydroascorbate and ascorbate in mammalian cells; Koch CJ et al.; Dehydroascorbate, an electron affinic metabolite of vitamin C, sensitized Ehrlich ascites tumor cells, in vivo, to radiation and was selectively toxic to V79 Chinese hamster lung cells under hypoxic conditions (without radiation) . The radiosensitization may involve both the electron affinic nature of dehydroascorbate as well as its ability to oxidize the intracellular NAD(P)H and non-protein sulfhydryl . Dehydroascorbate's oxidation of NAD(P)H required higher concentrations than other sulfhydryl oxidants such as N-ethylmaleimide and diamide . The oxidation of NAD(P)H by dehydroascorbate could be reversed by glucose . Hypoxic cell radiosensitization of V79 cells in tissue culture by dehydroascorbate could not be easily demonstrated because of the rapid breakdown and appreciable cytotoxicity of the drug at high concentration . The cytotoxicity was found to occur with both high and low densities of V79 cells . With low cell densities small amounts of oxygen did not reduce the cytotoxicity of dehydroascorbate, but virtually eliminated the cytotoxicity of nitroaromatic electron affinic compounds (metronidazole and Ro-07-0582) . The cytotoxicity to dense cell suspensions was found to depend upon the type of buffer included in the reaction medium . The maximum cytotoxicity was obtained in buffer free saline . The reduced form of dehydroascorbate, vitamin C, was found to be toxic only under aerobic conditions . The aerobic cytotoxicity could be prevented by the addition of catalase to the growth medium or by an increase in cell density, suggesting it was caused entirely by the production of H2O2 from the oxidation of vitamin C.

Biochim Biophys Acta, 1978 Feb 16, 517(2), 407 - 18
Studies of the catalytic properties of an endonuclease isolated from Tetrahymena pyriformis; Matsokis N et al.; An acid endonuclease hydrolyzing both DNA and RNA was purified from Tetrahymena pyriformis, strain E . The enzyme is distributed in all major subcellular compartments and is excreted into the growth medium towards the middle of the logarithmic phase . It hydrolyzes DNA to penta or hexanucleotides, on the average, bearing the monoesterified phosphate at the 3'-position . Particularly in early phases of the reaction it shows a very pronounced specificity for bases with a keto group at position 4 of the pyrimidine ring, such as guanine and thymine.

Arch Dermatol Res, 1978 Feb 15, 261(1), 27 - 31
Long-term tissue culture of epithelial-like cells from human skin (NCTC strain 2544) . II . Viscosity changes after enzyme treatment; Neufahrt A et al.; Human skin epithelial-like cells (NCTC strain 2544) were grown in NCTC 135 medium . Neuraminidase and hyaluronidase were added to the growth medium . Cells were incubated 96 h at 36 degrees C . Growth rate and viscosity of cell suspensions were measured after forming single cells mechanically (mopping) . With addition of neuraminidase and hyaluronidase, respectively, the growth rate remains unchanged . With neuraminidase a distinct raise in viscosity was achieved, whereas with hyaluronidase only a small effect was seen . The characteristic structure viscosity is maintained in all forms of the viscosity curves at different shear-rates.

Experientia, 1978 Feb 15, 34(2), 179 - 81
Effect of low density lipoprotein on proteoglycan synthesis by aorta cells in culture; Ehrlich K et al.; Increasing the content of human serum low density lipoprotein in the growth medium led to greater incorporation of 35S-sulfate into proteoglycan (mostly into dermatan sulfate) by primary aorta cells but did not affect similar incorporation by fibroblast cells . These results suggest a mechanism which can explain the increased deposition of lipid in aorta due to hyperlipidemia.

J Protozool, 1978 Feb, 25(1), 30 - 3
Fine structure of the cell surface and Golgi apparatus of Ochromonas; Kahan D et al.; Ochromonas danica has an unusually flexible cell surface capable of producing projections of varying sizes and shapes: large projections, 340-360 nm long, and small projections, 50-110 nm long . These projections have been demonstrated by transmission and scanning electron microscopy; some of them may break off into the medium and be the source of extracellular membranes and vesicles reported in the cell-free O . danica growth medium . Ruthernium red stained the acid mucopolysaccharide layer just outside the cell surface as well as small blebs at the cell surface . The Golgi complex of O . danica, Ochromonas malhamensis, Ochromonas sociabilis and Ochromonas sp . produced small coated vesicles which may move toward and fuse with the plasma membrane . The role of the several vesicles is unknown but possible functions are discussed.

Biull Eksp Biol Med, 1978 Feb, 85(2), 202 - 5
{Microcinematographic study of pancreatic islet cells from fetal cattle}; Bliumkin VN et al.; The growth characteristics of pancreatic islet cell cultures of bovine fetuses were investigated by the method of time-lapse cinemicrography . These monolayer cultures consisted of epithelial cells only . Under the influenc of high glucose concentration in the growth medium (up to 300 mg per 100 ml) there occurred an activation of mitochondrial apparatus of the islet cells, stimulation of cytogranulokinesis, and intensification of accumulation of the secretory granules with the subsequent degranulation of the islet cells . These data were compared with the results of cytological control of fixed and stained culture.

J Histochem Cytochem, 1978 Feb, 26(2), 94 - 7
An immunocytochemical study of a rat pituitary multipotential clone; Bowie EP et al.; The 2A8 clone, a normal diploid rat anterior pituitary cell strain, was investigated by immunocytochemistry to determine the cell types into which the clonal cells differentiated in vivo and in vitro . The in vivo study was carried out by injecting the 2A8 clone preparation either into the hypothalamic region or under the kidney capsule . After thirty days the implants were removed and studied by immunocytochemistry . In vitro, many prolactin cells and a few growth hormone cells were found . In vivo, however, prolactin, growth hormone, ACTH and TSH cells and gonadotrophs were identified . We concluded that the 2A8 clone was multipotential . Since the gonadotrophs of the implants made in the hypothalamic region were larger and more plentiful than those in the kidney implants, and since gonadotrophs were lacking in the in vitro system, it appeared that the hypophysiotrophic environment was the most conducive to gonadotrophic differentiation and maintenance, and that the factor or factors necessary for cyto-differentiation were apparently present in the general circulation of the rat but absent in the growth medium of our culture cells.

Cell Tissue Res, 1978 Jan 9, 186(1), 53 - 61
Accumulation of secretory granules in pituitary clonal cells derived from the epithelium of Rathke's pouch; Shiino M et al.; 2A8 clonal cells derived from the epithelium of Rahtke's pouch of the fetal rat are essentially agranular when grown in vitro, in spite of their active secretion of hormones, i.e., ACTH, prolactin and growth hormone . These cells do not produce detectable amounts of thyrotrophic or gonadotrophic hormones in vitro . When the growth medium (Ham's F10) was supplemented with rat median eminence extract (MEE), L-thyroxin and fresh serum from hypophysectomized rats, some of the 2A8 cells accumulated and stored secretory granules which were characteristic of the cells of the intact pituitary gland . Typical thyrotrophic and gonadotrophic cells also became recognizable and all six anterior pituitary hormones were released into the culture medium . Growth of 2A8 cells in this modified culture medium resulted in an increased production of all hormones with increasing time in culture . These results indicate that the processes that lead to the accumulation of typical mature secretory granules which characterize the individual pituitary cell types are initiated or promoted by some unidentified factor or factors which are present in fresh rat serum . It is also apparent that fresh rat serum can promote the differentiation of gonadotrophs and thyrotrophs in vitro.

Cytobios, 1978, 21(81), 7 - 21
In vitro induction of uncoiled chromosomes with inhibitors of RNA and protein synthesis; Ronne M et al.; When inhibitors of cellular DNA, RNA or protein synthesis are added to the growth medium of human lymphoid cells in G2 phase, these agents produce, within narrow ranges of concentrations, G banded or uncoiled chromosomes in the treated metaphase cells . It is suggested that the induced structural alteration is a consequence of an inhibition of the normal chromosome condensation and fusion of bands taking place between prometaphase and metaphase . This inhibition seems to be due to a partial inhibition of G2 phase synthesis of RNA and protein molecules, necessary for normal chromosome condensation in metaphase . It is found that this condensation can be reversed during a resting period after metaphase.

Z Allg Mikrobiol, 1978, 18(8), 575 - 86
Characterization of the virulent actinophage S2; Klaus S et al.; The virulent actinophage S2 isolated from soil infects Streptomyces hygroscopicus 6599, S . lividans 66, and S . levoris 1331 . Morphology of S2 was studied by electron microscopy . Influence of growth medium and temperature on multiplication of S2 has been studied qualitatively . S2 is more sensitive to UV irradiation on strain 66 than on 1331 . In contrast to UV, hydroxylamine mutagenesis delivered 9 stable ts mutants which belong to 3 complementation groups . Most of the ts mutations isolated on 1331 were found to be host dependent, 8 of 9 mutants were found to be able to grow at 40 degrees C on strain 66 but none of them on 1331 . Moreover 2 of the mutants were found to be much more heat sensitive in 6599 than in 1331, as indicated by the changes in half-life temperatures . The latent period of S2+ depends on temperature and germination state of the spores . Under optimal conditions we found 140 min . Ts2 and ts7 have been classified as a late and ts17 as an early mutant.

Folia Microbiol (Praha), 1978, 23(4), 299 - 303
Studies on xylan hydrolases from different strains of Streptomyces and their mutual influences in the breakdown of xylan; Sreenath HK et al.; A good proportion of Sreptomyces isolates from natural sources produced extracellular xylan hydrolase . Nineteen isolated showing high activity were able to completely or partially degrade wheat bran in the growth medium . Chromatographic analysis of commercial xylan degradation products suggested that the isolates produced either endo- or exo-xylan hydrolases or their mixtures . Mixed additions of culture fluids showed a highly synergistic effect, up to an increase by 200% . In a few cases antagonism was seen which, however, could be removed by dialysis of the culture fluid.

J Antibiot (Tokyo), 1978 Jan, 31(1), 74 - 81
Sub-unit assembly in the biosynthesis of neomycin . The synthesis of 5-O-beta-D-ribofuranosyl and 4-O-beta-D-ribofuranosyl-2,6-dideoxystreptamines; Pearce CJ et al.; The preparation of the deoxy- analogues of two pseudodisaccharide fragments of neomycin, 5-O-beta-D-ribofuranosyl-2,6-dideoxy-streptamine and 6-deoxyneamine is described . When added to the growth medium of a deoxystreptamine-idiotroph of Streptomyces rimosus forma paromomycinus only the latter was incorporated into antibiotic, suggesting an obligatory order for the assembly of sub-units . 4-O-beta-D-Ribofuranosyl-2,6-dideoxystreptamine was also prepared . When added to the growth medium of a deoxystreptamine-idiotroph of Streptomyces fradiae it was converted into the 6-deoxyneomycins, apparently after hydrolysis to 2,6-dideoxystreptamine . The structure of the protected derivatives of the ribofuranosyl 2,6-dideoxystreptamines, potentially useful intermediates for the synthesis of novel antibiotics, was shown by using 15C NMR spectroscopy.

Antibiot Chemother, 1978, 23, 26 - 32
A multi-end point in vitro system for detection of new antitumor drugs; Hanka LJ et al.; By utilizing new types of producing microorganisms and isolating these on rather unusual growth media, we hope to produce new classes of antitumor drugs . In the detection system, we included the highly sensitive L1210 in vitro assay . But be requiring additional antimicrobial activity, we were able to eliminate rather early most of the previously known drugs from further work-up . The screening protocol was arranged so as to detect antimetabolites of a few rationally selected compounds.

Mikrobiologiia, 1978 Jan-Feb, 47(1), 26 - 31
{Optimization of the conditions for beta-galactosidase biosynthesis in eukaryotes}; Tikhomirova AS et al.; Liquid whey can be subsituted by dry whey in the growth medium for Saccharomyces fragilis producing endocellular beta-galactosidase . The total biosynthesis of beta-galactosidase by the yeast on the medium containing dry whey can be increased by 40-50 percent as a result of additional stepwise introduction of lactose into the medium or optimization of the medium by mathematical planning of the experiment . Constructive metabolism of the yeast is not correlated with the rate of biosynthesis of beta-galactosidase . Damages in constructive metabolism of facultative anaerobes - yeast cultures - caused by the limitation of aeration result in an increase of the rate of beta-galactosidase biosynthesis . Such a correlation between the rate of the enzyme biosynthesis and the degree of aeration of the culture is not found in strict aerobes - fungi Alternaria tenuis and Curvularia inaequalis.

Genetika, 1978, 14(1), 163 - 70
{Competence in Escherichia coli cells . V . Interaction of the competence factor with the cells}; Rudchenko ON et al.; Some trends of the interaction of the competence factor with the cells are described on the model of phage lambda transfection . It is shown that this process depends on the composition of the recipients growth media, the temperature regime in the interaction processand on the concentration of the competence factor and the recipient cells . The preliminary treatment of the recipient by EDTA (0.0001 M), CaCl2 (less than 0.02 M), MgCl2 (less than 0.01 M), and NaCl (less than 0.01 M) resulted in the increaze of their sensitivity to subsequent treatment by the factor . Data are obtained demonstrating that after the treatment of cells by the competence factor their sensitivity to decreased CaCl2 concentration is increasing.

J Bacteriol, 1978 Jan, 133(1), 320 - 8
Effect of thymine concentration on cell shape in Thy- Escherichia coli B/r; Meacock PA et al.; Cells of a thymineless mutant of Escherichia coli B/r are shown to change their shape when the concentration of thymine in the growth medium is reduced . Electron micrographs of whole cells and isolated sacculi were used to make quantitative measurements of the changes in cell length and width which occur as a result of such a change in thymine concentration . The results showed that there is an increase in cell volume, which is due to an increase in cell width accompanied by a decrease in cell length . These changes were compared with the predictions of models which assume that cell shape is influenced by the chromosome replication cycle.

Antonie Van Leeuwenhoek, 1978, 44(3-4), 311 - 20
A mutant of Saccharomyces cerevisiae lacking catabolic NAD-specific glutamate dehydrogenase . Growth characteristics of the mutant and regulation of enzyme synthesis in the wild-type strain; Middelhoven WJ et al.; NAD-specific glutamate dehydrogenase (GDH-B) was induced in a wild-type strain derived of alpha-sigma 1278b by alpha-amino acids, the nitrogen of which according to known degradative pathways is transferred to 2-oxoglutarate . A recessive mutant (gdhB) devoid of GDH-B activity grew more slowly than the wild type if one of these amino acids was the sole source of nitrogen . Addition of ammonium chloride, glutamine, asparagine or serine to growth media with inducing alpha-amino acids as the main nitrogen source increased the growth rate of the gdhB mutant to the wild-type level and repressed GDH-B synthesis in the wild type . Arginine, urea and allantoin similarly increased the growth rate of the gdhB mutant and repressed GDH-B synthesis in the presence of glutamate, but not in the presence of aspartate, alanine or proline as the main nitrogen source . These observations are consistent with the view that GDH-B in vivo deaminates glutamate . Ammonium ions are required for the biosynthesis of glutamine, asparagine, arginine, histidine and purine and pyrimidine bases . Aspartate and alanine apparently are more potent inducers of GDH-B than glutamate . Anabolic NADP-specific glutamate dehydrogenase (GDH-A) can not fulfil the function of GDH-B in the gdhB mutant . This is concluded from the equal growth rates in glutamate, aspartate and proline media as observed with a gdhB mutant and with a gdhA, gdhB double mutant in which both glutamate dehydrogenases area lacking . The double mutant showed an anomalous growth behaviour, growth rates on several nitrogen sources being unexpectedly low.

IARC Sci Publ, 1978, (24 Pt 1), 253 - 60
Altered biological and biochemical properties of a phosphonoacetate-resistant mutant of herpesvirus of turkeys; Lee LF et al.; A phosphonoacetate (PA)-resistant mutant of the herpesvirus of turkeys (HVT) was isolated and characterized . The mutant (HVTpa) replicates in growth medium containing 300 microgram/ml of PA and shows in vitro temperature sensitivity at 41 degrees C (its 37 degrees C/41 degrees C efficiency of replication is about 5) . HVTpa replicates poorly in chickens and fails to provide complete protection against MDV challenge . The HVTpa-induced DNA polymerase has an apparent inhibition constant for PA 10 times as great, an apparent inhibition constant for pyrophosphate, twice as great, and an apparent Michaelis constant for dCTP 2.5 times as great as the respective figures for the HVTwt-induced enzyme . The HVTpa-induced enzyme is also more thermolabile.

Mikrobiologiia, 1978 Jan-Feb, 47(1), 5 - 10
{Changes in the electron transport chain in Escherichia coli depending on the cultivation conditions and growth phase}; Trutko SM et al.; Changes in the electron transport chain of E . coli K-12 were studied as a function of the growth phase and the nature of a terminal electron acceptor in the growth medium . The content of flavins in the preparations of bacterial membranes hardly changed in all cases . The highest concentration of quinones was observed in the bacterial membranes at the stationary growth phase under anaerobic conditions of growth in the presence of nitrate . These membranes contained also the greatest amount of cytochrome beta1 . The concentration of cytochrome alpha2 in all the membranes was low and varied among different preparations . All the membranes contained a CO-binding pigment whose content was maximal in the membranes of "nitrate" cells . The membranes of cells grown under aerobic conditions oxidized malate, apart from NADH and lactate, whereas the membranes of cells cultivated under anaerobic conditions in the presence of nitrate oxidized formiate . In most cases, the oxidase activity of the membranes of cells collected at the stationary growth phase was higher cf . the exponential phase.

Cancer Res, 1978 Jan, 38(1), 185 - 8
Turnover of cellular carbohydrates in normal and Rous sarcoma virus-transformed cells; Leonard JG et al.; We have analyzed the distribution of glucosamine-labeled polymers on the cell surface, in the growth medium, and inside the cell and the net turnover of these polymers during the process of malignant transformation of chick embryo fibroblasts by Rous sarcoma virus . The distribution of label and the turnover kinetics for hyaluronic acid, total glycoproteins, and chondroitins were found to be identical in both normal and transforming cultures . We conclude that nonspecific degradative processes are probably not involved in causing transformation-related alterations in cell surface carbohydrates, althougn degradation of specific macromolecules is not excluded.

Mol Gen Genet, 1977 Dec 14, 158(1), 81 - 91
Changes in regulation of ribosome synthesis during different stages of the life cycle of Saccharomyces cerevisiae; Pearson NJ et al.; Diploid strains of Saccharomyces cerevisiae, each homozygous for one of the temperature sensitive mutations rna2, rna3, rna4, rna6 or rna8, are temperature sensitive for ribosome synthesis during vegetative growth, but are not inhibited for ribosomal synthesis at the restrictive temperature under sporulation conditions . The continued ribosome biosynthesis at the restrictive temperature (34 degrees C) during sporulation includes de novo synthesis of both ribosomal RNA and ribosomal proteins . This lack of inhibition of ribosome biosynthesis is found even when cells committed to complete sporulation are returned to vegetative growth medium . The ribosomes synthesized at 34 degrees C are apparently functional, as they are found in polyribosomes . Although the rna mutants do not regulate ribosome synthesis during sporulation, all of these diploid strains fail to complete sporulation at 34 degrees C . The cells are arrested after the second meiotic nuclear division but before ascus formation . The failure to complete sporulation at the restrictive temperature and the inhibition of ribosome biosynthesis during growth are caused by the same mutation, because revertants selected for temperature independent growth were also able to sporulate at 34 degrees C.

Mol Gen Genet, 1977 Dec 14, 158(1), 111 - 6
Caffeine enhancement of radiation killing in different strains of Saccharomyces cerevisiae; Hannan MA et al.; Haploid and diploid wild type strains, and three classes of radiation-sensitive mutants of Saccharomyces cerevisiae were tested for enhancement of UV-inactivation by caffeine in growth medium . In addition, the sensitizing effect of caffeine was studied in a haploid and a diploid wild type strain after gamma-irradiation . The drug sensitized the UV-irradiated cells of all strains except those reported to be only slightly UV-sensitive but highly sensitive to ionizing radiation . After gamma-irradiation, no caffeine-enhancement of killing was observed in stationary phase cells of either the haploid or the diploid strain . However, log-phase cells of both strains were partially sensitized . The results of both sets of experiments suggested that caffeine interferes with a recombinational repair occurring in cells in S or G2 phase.

Cell Tissue Res, 1977 Dec 13, 185(2), 183 - 90
Modification of Drosophila cell surfaces by concanavalin A; Rizki RM et al.; The effect of Con A on the surface morphology of cultured cells of Drosophila melanogaster growing on coverglasses was examined by scanning electron microscopy . With low lectin concentrations (5--10 microgram/ml) surface filaments disappeared and the cells flattened and spread against the glass surface . Cytoplasmic fusion bridges were observed in areas where cells made contact . Concentrations of Con A ranging between 50--500 microgram/ml caused cell shrinkage and surface distortions without cell flattening and filament loss . These morphologic effects were not apparent if Con A binding sites were blocked by preincubation with alpha-methyl-D-mannopyranoside before application to the cell cultures . However, once the Con A-mediated changes were in effect, the cells failed to show recovery when they were returned to growth medium and a majority of the cells on the coverglasses degenerated . Presumably the cells whose morphology appears unaffected by Con A treatment are the survivors that repopulate cultures returned to growth medium.

Biomedicine, 1977 Dec, 27(9-10), 344 - 9
Regulation of haemopoietic stem cell proliferation in long term bone marrow cultures; Dexter TM et al.; The development of a suitable bone marrow derived adherent cell population appears to be essential for the prolonged maintenance of haemopoietic stem cells in vitro . When established adherent layers are inoculated with freshly isolated bone marrow cells, proliferation of stem cells (CFU-S) regularly occurs both in the adherent layer and amongst the non-adherent cells . Furthermore, CFU-S present within the adherent layer are able to regenerate both themselves and the "non-adherent" CFU-S . One day after re-feeding the cultures (by removal of half the growth medium and addition of fresh medium) both the "non-adherent" and the "adherent" CFU-S are in a high cycling state (greater than 40% kill with 3HTdR) . This proportion decreases with time of re-feeding and 5-7 days later the majority of "adherent" and "non-adherent" CFU-S are in a low cycling state ( less than 10% 3HTdR kill) . Following a further re-feeding, CFU-S again enter a high cycling state.

Mol Biol Rep, 1977 Dec, 3(6), 421 - 8
Stabilization of mRNA following serum-induction of quiescent 3T3 cells; Bandman E; The stability of mRNA has been measured in 3T3 cells in the resting and the growing states, and also during the transition from the resting to the growing state . Pulse labled poly (A)+ mRNA chased with uridine and cytidine supplemented growth medium decayed with a half-life of 6.5 hr in the resting state, 26 hr during the transition from the resting to the growing condition, and 18 hr during serum-stimulated growth . The half-life of poly(A)+ mRNA determined by steady state labeling yielded similar results in resting and serum-stimulated 3T3 cells . Thus during the transition from resting to serum-stimulated growth in 3T3 cells poly(A)+ mRNA becomes more stable.

Chem Biol Interact, 1977 Dec, 19(3), 339 - 51
Effect of triethyltin on Escherichia coli K-12; Leo AC et al.; Triethyltin (TET) stimulated the basal respiration of Escherichia coli K-12 membrane vesicles in chloride (Cl-) medium but it had little effect on respiration in sulphate (SO4(2-)) medium . Since this uncoupling activity was Cl- dependent it was attributed to the Cl-/hydroxide (OH-) exchange reaction known to be mediated by TET {1,2} . TET inhibited the oxidation of succinate by intact E . coli in both Cl- and SO4(2-) medium, but at the same concentration of TET, inhibition was always more extensive in Cl- than SO4(2-) medium . In Cl- medium uncoupling in membrane vesicles and inhibition of succinate oxidation in intact bacteria occurred over the same concentration range and it appeared that the same mechanism, i.e . Cl-/OH- exchange, was responsible for both effects . Inhibition of succinate oxidation in SO4(2-) medium was not substantial until the concentration of TET was greater than 10(-5) M . Although the nature of this inhibition could not be determined by experiments with membrane vesicles indirect evidence from growth experiments indicated that it was due to impairment of oxidative phosphorylation . The relationship between these biochemical findings and the bacteriocidal action of TET was examined by using various concentrations of anion and substrate in the growth medium . Growth was inhibited in media containing either Cl- or SO4(2-) as the main anion but at a particular concentration of TET, inhibition was greater in Cl- medium . Growth was also inhibited to a greater extent in succinate than glucose medium . Furthermore in either Cl- or SO4(2-) glucose medium, lactic acid production increased as the concentration of TET was increased . These findings imply that the bacteriocidal action of TET is related to its effect(s) on oxidative phosphorylation.

J Pharmacol Exp Ther, 1977 Dec, 203(3), 610 - 20
Control of cyclic adenosine 3':5'-monophosphate-elevating effect of adenosine in C-1300 murine neuroblastoma in tissue culture; Green RD; The elevation of cyclic adenosine 3':5'-monophosphate (cyclic AMP) in response to adenosine in C-1300 murine neuroblastoma (clone N2a) in surface culture is increased in magnitude in cultures pretreated overnight with theophylline or adenosine deaminase . This "potentiating" effect of theophylline takes time to develop and is blocked by cycloheximide . The cyclic AMP-elevating effect of adenosine decreases in magnitude as the cultures approach confluence . This reduced responsiveness is reversed by the overnight treatment with theophylline . It is hypothesized that adenosine is continually released by the cells to the growth medium and that this adenosine acts extracellularly to modulate the sensitivity of the cells to the cyclic AMP-elevating effect of adenosine.

J Bacteriol, 1977 Dec, 132(3), 1042 - 4
Germination-defective mutant of Neurospora crassa that responds to siderophores; Charlang G et al.; A conditionally germination-defective mutant of Neurospora crassa has been found to be partially curable by ferricrocin and other siderophores . The mutant conidia rapidly lose their membrane-bound siderophores when suspended in buffer or growth media . Germination is consequently delayed unless large numbers of conidia are present (positive population effect) . This indicates that the mutant has a membrane defect involving the siderophore attachment site.

Brain Res, 1977 Nov 4, 136(1), 131 - 40
Ascorbic acid transport by a clonal line of pheochromocytoma cells; Spector R et al.; A clonal line of rat pheochromocytoma cells was used as a model of noradrenergic tissue to study ascorbic acid transport . These cells were used because, like sympathetic neurons, they synthesize large amounts of noradrenaline in the presence of ascorbate, they respond to nerve growth factor with the production of neurites and they release, store and take up catecholamines . In these cells, both with and without nerve growth factor (NGF) treatment, {14C}ascorbic acid was concentrated by a stereospecific saturable, energy dependent transport system that could be described by a Michaelis-Menten transport model . The Kt and Vmax for ascorbic acid were approximately 0.03 mM and 0.3 nmole per min per mg protein respectively for both untreated and NGF-treated cells . The ability of the cells to concentrate ascorbic acid was not due to intracellular binding . Cells untreated with NGF and loaded with {14C}ascorbic acid to a concentration of 5.6 nmoles per mg protein retained only 6% of the initial intracellular {14C}ascorbic acid after the 24 h in normal growth medium . Thus, although pheochromocytoma cells contain an ascorbate concentrating system, optimal production of noradrenaline requires ascorbate in the medium.

J Clin Microbiol, 1977 Nov, 6(5), 538 - 42
Modified Lombard-Dowell broth as a general growth medium; Jessee MT et al.; A new liquid medium (modified Lombard-Dowell broth) was inoculated with stock culture strains of aerobic and anaerobic bacteria and compared with prereduced chopped-meat glucose inoculated with the same anaerobes . Both broths were subcultured at 48 and 72 h to aerobic and anaerobic blood agar plates, and the numbers of colonies were compared after 48-h incubation of the agar plates . This was repeated with mixed cultures of both aerobes and anaerobes . For a period of 11 months all specimens received for anaerobic-aerobic culture were inoculated into prereduced chopped-meat glucose and modified Lombard-Dowell broth plus the appropriate plate medium . Growth from subcultures was compared with primary plate isolates . Chopped-meat glucose and modified Lombard-Dowell broth isolates agreed, with the exception of one, Fusobacterium necrophorum, that did not grow in chopped-meat glucose.

Can J Microbiol, 1977 Nov, 23(11), 1562 - 7
Nitrate-reductase electron-transport cofactors in Veillonella alcalescens; Ruoff KL et al.; Studies on the effects of inhibitors of the nitrate-reducing activity of Veillonella alcalescens extracts suggest the participation of a naphthoquinone, a b-type cytochrome, and non-heme iron in electron transport to nitrate . A nitrate-reductase-deficient mutant displayed a longer doubling time and a decreased molar growth yield on nitrate media . This mutant was phenotypically restored by the addition of molybdate to the growth medium, giving evidence for the functioning of molybdenum in the nitrate-reductase enzyme of V . alcalescens.

Mikrobiologiia, 1977 Nov-Dec, 46(6), 1007 - 13
{Influence of the composition of the medium and the duration of cultivation on the growth of Actinomyces spheroides and their biosynthesis of intracellular proteases and novobiocin}; Egorov NS et al.; The growth of Actinomyces spheroides 35 under different conditions and the biosynthesis of biomass, proteases and the antibiotic were studied with two types of growth medium: a control one and an optimized one . The rate of biomass accumulation was by 5--7 per cent higher on the latter medium than on the former one . The dynamics of accumulation was studied with novobiocin and proteases which hydrolyzed fibrin and casein . Fibrin hydrolyzing proteases were found to be synthesized under conditions that were unfavourable for the production of novobiocin . If the production of the antibiotic was supressed, the concentration of fibrinolytic proteases in the cultural broth increased almost proportionally . Such a relation has not been found for caseinolytic proteases.

Br J Cancer, 1977 Nov, 36(5), 558 - 63
A method for detecting carcinogenic organic chemicals using mammalian cells in culture; Styles JA; A method for testing organic chemicals for their carcinogenic potential is described . Baby hamster kidney cells (BHK-21/C1 13) were exposed to different doses of test compound in liquid tissue culture medium containing rat liver post-mitochondrial supernatant and cofactors (S-9 mix) to aid metabolism, but without serum . Survival of cells following exposure to the compound was assessed by cloning in liquid growth medium . Transformation was assessed by colony growth in semi-solid agar . The dose-response curve for survival was used to determine the LC50 of the compound . A dose-response curve for transformation was constructed and a 5-fold increase in transformation frequency at the LC50 was regarded as a positive test result . The method may also be used for testing gaseous compounds . Cells grown in monolayers and overlaid with serum-free medium and S-9 mix were exposed to vinyl chloride gas mixed with air . After exposure, the treated cells were trypsinized, resuspended in growth medium, and survival and transformation assays performed . The methods described are illustrated by examples taken from an evaluation study using 120 compounds and found to be more than 90% accurate in distinguishing between carcinogens and non-carcinogens.

J Cell Physiol, 1977 Nov, 93(2), 237 - 46
The regulation by fibroblast growth factor of early transport changes in quiescent 3T3 cells; Quinlan DC et al.; This study involves the use of fibroblast growth factor (FGF) as a substitute for exogenous serum to examine the early transport changes which occur when quiescent 3T3 cells re-initiate active growth . FGF, in nanogram amounts, together with insulin and dexamethasone, can induce mitogenesis and mitosis in 3T3 cells GO-arrested by holding in growth medium containing 0.8% calf serum . In terms of quiescent cell transport activity enhancement, FGF is 300,000-fold more effective than fresh serum, on a protein basis . In addition, very short exposure of serum-depleted cells to FGF indicates that a distinct temporal or time sequence exists in the transport system activation process . For example, uptake of alpha-aminoisobutyric acid (AIB) and uridine are stimulated very rapidly, whereas hypoxanthine uptake does not respond until much later . Closer analysis shows that AIB uptake is maximally enhanced within zero to two minutes after FGF addition to cells . Finally, the stimulatory effect of FGF on transport system activities is specific in terms of the proliferative state of the cells to which it is added, and in terms of the uptake systems which respond to it.

J Virol, 1977 Nov, 24(2), 514 - 7
Role of potassium in the synthesis and decay of two specific bacteriophage T4 messages; Walsh ML et al.; The role of K+ in the in vivo metabolism of specific phage T4 messengers was studied . By using a mutant of Escherichia coli defective in its ability to accumulate K+ from the growth medium, it was possible to rapidly deplete cells of their intracellular K+ and in this way determine K+-dependent reactions in vivo . The rate constants for accumulation, synthesis, and decay of the early enzymes deoxynucleotide kinase and alpha-glucosyl transferase were determined . It was shown that there is a very close association between mRNA synthesis and its decay, indicating that a mechanism may be present in the cell that can regulate the concentration of these RNAs . Since the mRNA's for these enzymes are very stable in cells depleted of K+, K+ depletion may be a useful method for the isolation of functional T4 mRNA.

J Natl Cancer Inst, 1977 Nov, 59(5), 1509 - 18
Transformation of rat liver epithelial cells by Kirsten murine sarcoma virus; Rhim JS et al.; We studied the transformation of epithelial, diploid cell lines (RL-33 and RL-34) derived from W rat liver by the Kirsten murine sarcoma virus . On days 4-5 after virus infection, the epithelial cells began to pile up focally, forming small projections and releasing round cells from the foci . The epithelial cells grew in chains or as islets and grew in suspension above the cells attached to the bottom of the flasks when the cultures reached the confluent stage . The virus titration pattern was "one-hit." Three classes of transformed cells were isolated with respect to virus release and antigen expression: 1) virus producer, 2) non-producer, and 3) sarcoma-positive, leukemia-negative cells . When transplanted sc into newborn rats, the transformed cells produced sarcomas . The transformed cells formed within 1-3 days larger aggregates than those of their normal counterpart cells when suspended in liquid growth medium above an agar base . Aggregate properties (size, viability, and proliferation) of transformed cells correlated with growth in soft agar and tumorigenicity . RNA-dependent DNA polymerase and type C virus particles were readily induced in the normal rat liver epithelial cells after exposure to 5-iodo-2'-deoxyuridine.

J Bacteriol, 1977 Nov, 132(2), 520 - 5
Adaptive changes in phosphate uptake by the fungus Neurospora crassa in response to phosphate supply; Beever RE et al.; The phosphate uptake rate of Neurospora crassa germlings growing exponentially in media containing phosphate at concentrations between 10 mM and 50 micronM was virtually constant . The uptake characteristics of these germlings were studied in detail assuming the simultaneous operation of two uptake systems, one of low affinity and one of high affinity . The Km of the low-affinity system was constant after growth at phosphate concentrations greater than 1 mM but became progressively lower as the concentration was reduced below 1 mM . In contrast, the Km of the high-affinity system was independent of the phosphate concentration of the growth medium . The Vmax of each system was highest after growth at low phosphate concentrations . As the phosphate concentration was increased to a maximum of 100 mM, the Vmax of the low-affinity system fell gradually, whereas that of the high-affinity system at first fell rapidly but then reached a constant minimum value at concentrations of 2.5 mM and higher . The differences in the kinetic parameters fully account for the constancy of uptake rate shown by the germlings.

J Bacteriol, 1977 Nov, 132(2), 511 - 9
Kinetic characterization of the two phosphate uptake systems in the fungus Neurospora crassa; Burns DJ et al.; The kinetics of phosphate uptake by exponentially growing Neurospora crassa were studied to determine the nature of the differences in uptake activity associated with growth at different external phosphate concentrations . Conidia, grown in liquid medium containing either 10 mM or 50 micronM phosphate, were harvested, and their phosphate uptake ability was measured . Initial experiments, where uptake was examined over a narrow concentration range near that of the growth medium, indicated the presence of a low-affintiy (high Km) system in germlings from 50 micronM phosphate . Uptake by each system was energy dependent and sensitive to inhibitors of membrane function . No efflux of phosphate or phosphorus-containing compounds could be detected . When examined over a wide concentration range, uptake was consistent with the simultaneous operation of low- and high-affinity systems in both types of germlings . The Vmax estimates for the two systems were higher in germlings from 50 micronM phosphate than for the corresponding systems in germlings from 10 mM phosphate . The Km of the high-affinity system was the same in both types of germlings, whereas the Km of the low-affinity system in germlings from 10 mM phosphate was about three three times that of the system in germlings from 50 micronM phosphate.

Sabouraudia, 1977 Nov, 15(3), 313 - 23
Lipolytic enzymes of Trichophyton rubrum; Das SK et al.; Trichophyton rubrum cells contain lipase, phospholipases A and B and acyl CoA lysolecithin acyl transferase activities . This dermatophyte excretes lipase and phospholipase A into the growth medium when cultivated in Sabouraud's broth . Extracellular lipase has optimum activity at pH 8.0 whereas the intracellular lipase is maximally active at pH 8.0 whereas the intracellular lipase is maximally active at pH 7.0 . The optimum pH of phospholipase A and B activities which are localized in 15000 g sedimentable cell fragments are 7.0 and 6.0 respectively . Supernatant obtained after removal of 1,005,000 g sedimentable fragments from cell extract contains acyl CoA lysolecithin acyl transferase which requires ATP, CoA, Mg2+ and an unsaturated fatty acid for its activity.

Cancer Res, 1977 Oct, 37(10), 3634 - 8
Transferrin promotion of 67Ga and 59Fe uptake by cultured mouse myeloma cells; Harris AW et al.; Radiotracer 67Ga-citrate is used as a tumor-seeking agent in clinical imaging investigations although fundamental reasons for its high uptake in certain malignant lesions remain unexplained . The mechanism by which 67Ga becomes concentrated in tumor cells has been investigated by comparing 67Ga and 59Fe uptake by cultured mouse myeloma cells with particular reference to uptake stimulation by transferrin . Concentrations of human transferrin down to 2 microgram/ml greatly stimulated cellular uptake of both tracers, whereas bovine transferrin proved relatively inactive . The rates of stimulated uptake of both tracers were similar as was their high degree of retention by cells, but their quantitative dependencies on transferrin concentration showed characteristic differences . Pretreatment of human transferrin with saturating amounts of nonradioactive Fe3+ canceled its ability to promote 59Fe uptake, but it had little effect on its promotion of 67Ga uptake . Further increase in the amount of added Fe3+ did cause a progressive depression of 67Ga uptake, but this effect probably relates to the iron distribution in the whole-cell culture system including the fetal calf serum component of cell growth medium . The results suggest that 67Ga and 59Fe reveal different aspects of the interaction of transferrin with cells.

Acta Pathol Microbiol Scand {B}, 1977 Oct, 85B(5), 289 - 95
Induction of latent Herpes simplex virus type 2 infection in human cervical epithelial cells in vitro; Vesterinen E et al.; An in vitro method was used to induce non-productive herpes simplex virus type 2 (HSV-2) infections in human ecto- and endocervical epithelial cells . Adenine arabinoside (ara-A) could prevent the replication of HSV-2 in ecto- and endocervical cells and after removal of ara-A from growth medium a rapid destruction of explants with development of infectious virus was observed . When ara-A was not withdrawn until 4 days or later after in vitro infection the morphological, immunofluorescent and virological studies detected no infections . However, 2-3 weeks after inoculation there were in some cultures morphological as well as immunofluorescent signs of HSV infection without demonstrable infectious virus, indicating an incidental abortive nature of the infective process.

Can J Microbiol, 1977 Oct, 23(10), 1394 - 403
Uptake and efflux of adenine and its derivatives in Neurospora crassa; Pendyala L et al.; Conidia of wild-type Neurospora crassa, preincubated for 3 1/2 h in growth medium, showed a typical triphasic pattern of adenine uptake . The three phases consisted of a quick initial uptake, followed by a plateau phase, and then by a resume lowered uptake . A study of the relative influx and efflux of {14C} adenine showed that the plateau phase in fact is a period of transmembrane movement of adenine and adenine metabolites . The efflux during the plateau phase essentially cancelled out all the influx during the same period . The uptake curve derived after taking into account the effluxed portion of radioactivity indicated that the second phase represents a period of lowered uptake activity . The beginning of the lowered uptake activity during the second phase is correlated with the presence of a high intracellular level of ATP derived from exogenous {14C}adenine . At the end of the secod phase, the intracellular level of ATP is much smaller and the rate of adenine uptake increases again . Analysis of the acid-soluble pool after feeding {14C}adenine indicated the presence of other 14C-nucleotides, but no detectable levels of bases and nucleosides were present . However, chromatographic analysis of the medium indicated that efflux results essentially in the accumulation of bases . The significance of this finding in relation to efflux is discussed.

Lipids, 1977 Sep, 12(9), 729 - 40
The effct of cerulenin on sterol biosynthesis in Saccharomyces cerevisiae; Greenspan MD et al.; Cerulenin specifically inhibited fatty acid biosynthesis in Saccharomyces cerevisiae without having an effect on sterol formation . Ergosterol was not required for cell growth in the presence of cerulenin (1 microgram/ml) . The addition of fatty acids to the growth medium reduced the amount of ergosterol formed by 45%; further addition of cerulenin to the media had no effect on the amount of ergosterol synthesized by the cells . The incorporation of 3H from 3H2O into ergosterol was not affected by cerulenin whereas incorporation into fatty acids was inhibited by 90%.

Proc Natl Acad Sci U S A, 1977 Sep, 74(9), 3840 - 4
Glucose depletion accounts for the induction of two transformation-sensitive membrane proteinsin Rous sarcoma virus-transformed chick embryo fibroblasts; Shiu RP et al.; Chick embryo fibroblasts transformed by Rous sarcoma virus have an increased content of two membrane proteins of molecular weights 78,000 and 95,000 . The increased content of the 95,000-dalton protein and the principal increase in the content of the 78,000-dalton protein are not an early consequence of cell transformation but instead are secondary to the rapid depletion of glucose from the growth medium of transformed cells . When glucose is maintained at high levels in the growth medium of transformed cells, the synthesis of the 95,000-dalton protein is arrested and that of the 78,000-dalton protein is markedly suppressed . Upon removal of glucose from the growth medium of normal cells, these proteins increase to levels comparable to those of transformed cells . Because the amount of these two proteins is influenced by the presence or absence of glucose, we suggest they be referred to as "glucose-regulated proteins." GRP-78 and GRP-95 . These proteins may have an important role in regulating the utilization of glucose in cultured cells.

J Biol Chem, 1977 Aug 10, 252(15), 5310 - 5
Regulation of protein degradation in normal and transformed human cells . Effects of growth state, medium composition, and viral transformation; Bradley MO; In WI-38, a normal human fibroblast, the rates of degradation of short lived and long lived proteins are identical whether the cultures are growing exponentially or are density-inhibited . Replacement of the growth medium with fresh medium does not alter these rates . In VA-13, an SV-40 transformed derivative of WI-38, the rates of protein degradation are also independent of growth rate and fresh medium . However, in both WI-38 and VA-13 the rate of long lived protein degradation increases as the serum concentration is reduced below 5% . After complete serum withdrawal, the rate increases by 60 to 100% in both cell types . Withdrawal of arginine and phenylalanine triples the rate of long lived protein degradation, while addition of 10% dialyzed serum to this amino acid-deficient medium reduces the effect to twice that of the controls . Incubation of both types of cells in phosphate-buffered saline also increases protein degradation . This effect is reduced by glucose, albumin, and dialyzed serum . Therefore, the rate of protein degradation is independent of growth rate in normal and transformed human cells . However, the rate of degradation is closely coupled to certain medium alterations.

Nucleic Acids Res, 1977 Aug, 4(8), 2893 - 902
Photoreactivation and dark repair of ultraviolet light-induced pyrimidine dimers in chloroplast DNA; Small GD et al.; A UV-specific endonuclease was used to detect ultraviolet light-induced pyrimidine dimers in chloroplast DNA of Chlamydomonas reinhardi that was specifically labeled with tritiated thymidine . All of the dimers induced by 100 J/m2 of 254 nm light are removed by photoreaction . Wild-type cells exposed to 50 J/m2 of UF light removed over 80% of the dimers from chloroplast DNA after 24 h of incubation in growth medium in the dark . A UV- sensitive mutant, UVS1, defective in the excision of pyrimidine dimers from nuclear DNA is capable of removing pyrimidine dimers from chloroplast DNA nearly as well as wild-type, suggesting that nuclear and chloroplast DNA dark-repair systems are under separate genetic control.

Diabetes, 1977 Aug, 26(8), 798 - 803
Growth hormone antiserum suppresses the growth effect of diabetic serum . Studies on rabbit aortic medical cell cultures; Ledet T; Growth medium containing serum from young diabetic subjects caused a significant stimulation both of cell proliferation and of the outgrowth in cultures of rabbit aortic medial cells above that noted with normal human sera . The addition to the sera of guinea-pig human growth hormones antibody caused a marked inhibition of these stimulatory effects . The growth effect of rabbit serum was not affected by the human growth hormone antiserum . Reinvestigation of the effect of human growth hormone disclosed that the same increase as observed in growth with the diabetic sera could be obtained with a growth hormone concentration of 0.2 ng . per milliliter medium . The present results strongly suggest that the increased stimulatory effect of normolipemic human diabetic serum on growth and cell proliferation of aortic medial cell cultures is due to increased serum growth hormone concentration.

J Bacteriol, 1977 Aug, 131(2), 623 - 30
Influence of osmolarity of the growth medium on the outer membrane protein pattern of Escherichia coli; Alphen WV et al.; Supplementation of the growth medium with high concentrations of NaCl, KCl, or sucrose caused a drastic change in the ratio of the two peptidoglycan-associated major outer membrane proteins of Escherichia coli K-12 in that the amounts of proteins b and c present in cell envelope preparations decreased and increased, respectively . Kinetic studies showed that, after the osmolarity of the medium was changed, one protein was hardly incorporated into the membrane, whereas the other was incorporated with an increased rate . After about 1.5 to 2 generations, the cell envelopes obtained the b/c ratio characteristic for the new medium, and both proteins were subsequently incorporated in the cell ensured this new ratio . Once proteins b and c were incorporated in the cell envelope, they were not converted into each other by changes in osmolarity of the growth medium.

J Bacteriol, 1977 Aug, 131(2), 589 - 97
Two modes of metabolic regulation of lysyl-transfer ribonucleic acid synthetase in Escherichia coli K-12; Hirshfield IN et al.; Lysyl-transfer ribonucleic acid (tRNA) synthetase activity was compared in three independently isolated Escherichia coli K-12 mutants of the enzyme S-adenosyl-L-methionine synthetase (metK mutants) and their isogenic parents . In all three cases the activity of the lysyl-tRNA synthetase was elevated two- to fourfold in the mutant strains . Glycyl-L-leucine (3 mM) usually enhanced lysyl-tRNA synthetase activity two- to threefold in wild-type cells but did not further stimulate the synthetase activity in metK mutants . By two other criteria, the lysyl-tRNA synthetase from wild-type cells grown with the peptide and from the metK mutant RG62, grown in minimal medium, were similar . These criteria are enhanced resistance to thermal inactivation and altered susceptibility to endogenous proteases when compared with the synthetase from wild-type cells grown in minimal medium . In a separate set of experiments, the activities of the lysyl-, arginyl-, seryl-, and valyl-tRNA synthetases were measured in an isogenic pair of relt and rel strains of E . coli grown in a relatively poor growth medium (acetate) and in enriched medium . In the rel+ strain the level of all four synthetases was higher (two- to fourfold) in the enriched medium as expected . In the rel strain the difference in the activities of the synthetases between the two media were diminished . In all four cases the activities of the synthetases were higher in acetate medium in the rel strain . Evidence is presented that these two modes of metabolic regulation act independently.

Cancer Res, 1977 Aug, 37(8 Pt 2), 2969 - 73
Development and application of basic research techniques in bladder cancer research; Paulson DF et al.; The growth of transitional epithelial cells with different growth media and growth supports was examined . Sephadex G-10, Bio-Gel P-20, Bio-Glas-1000, DEAE-Sephadex A-50, DEAE-cellulose, CM-Sephadex C-50, acid-soluble collagen, and immobilized collagen fibers were used to enhance plating efficiency . Acid-soluble collagen layers optimally increased the plating efficiency of primary cultures of bladder carcinoma . Media alterations with serial combinations of fetal calf, newborn calf, calf, bovine, and bull serum with minimum essential medium, Roswell Park Memorial Institute Tissue Culture Medium 1640, Connaught Medical Research Laboratories Medium 1066, Medium 199, Grand Island Biological, National Cancer Tissue Culture 135, 1415, McCoy's 5A, and National Cancer Institute medium were established . No promotion of cell division was noted with any one of these basic medium formulations.

Biochim Biophys Acta, 1977 Jul 7, 461(1), 124 - 30
ZETA-Potential and surface charge of Thermoplasma acidophila; Hsung JC et al.; The surface charge density and the zeta-potential of Thermoplasma acidophila was estimated from microscopic electrophoresis experiments . The cells moved towards the positive electrode . The mobility remained constant from pH 2 to 5, and increased for pH values higher than 6 . The mobility at pH 6 decreased dramatically with increased external Ca2+ concentration . At pH 2 and an ionic strength similar to that of the growth medium, the zeta-potential was about 8 mV, negative relative to the bulk medium; the surface charge density was 1360esu/cm-2 which corresponds to one elementary charge per 3500 A2.

Mikrobiologiia, 1977 Jul-Aug, 46(4), 672 - 5
{Amino acid composition of Actinomyces mycelium}; Koval'chuk LP et al.; The mycelium of actinomycetes cultivated on different media contained 15-16 amino acids of an identical qualitative composition . The percentage of amino acids depended on the composition of a growth medium . Under conditions of our experiments, a chemically defined medium was most favourable for the synthesis of the following amino acids: alanine, hystidine, glutamic acid, leucine, and valine.

Infect Immun, 1977 Jul, 17(1), 91 - 7
Comparison of Coccidioides immitis arthrospore, mycelium, and spherule cell walls, and influence of growth medium on mycelial cell wall composition; Wheat RW et al.; Comparative lipid content, cell wall yield, neutral monosaccharide, glucosamine, and protein (amino acid) contents of arthrospores, mycelia, and spherules of Coccidioides immitis Cash were studied . Cellular lipid contents were found in the decreasing order: spherules, arthrospores, mycelia . Lipid content of mycelia did not reach the level of arthrospores or spherules even when mycelia were grown on relatively rich media . Cell wall yields of spherules were lower than for mycelia when grown on comparable media . Cell walls of arthrospores, mycelia, spherules, and spherule culture filtrate all contained 3-O-methylmannose, mannose, and glucose, but in varying amounts . Cell wall yield and cell wall glucose content increased in mycelia grown in increasingly rich media, whereas mannose content either decreased or remained constant.

J Bacteriol, 1977 Jul, 131(1), 340 - 6
Caulobacter crescentus pili: structure and stage-specific expression; Lagenaur C et al.; Pili are functionally expressed during the predivisional and swarmer stages of the Caulobacter crescentus differentiation cycle . They appear on the developing swarmer pole and at the same cellular location as flagella and the phiCbK receptor sites . Pili disappear when the swarmer cell differentiates into a stalked cell; this occurs with the loss of flagella and the disappearance of phage receptor sites . C . crescentus CB13B1a pili have been purified and characterized . Monomeric pilin is a protein with an apparent molecular weight of 8,500 that stains weakly with periodic acid-Schiff reagent . The amino acid composition of purified pilin reveals very low quantities of basic amino acids and a complete absence of methionine . Pilin is synthesized throughout the C . crescentus differentiation cycle . Neither free pili nor pilin monomers are detectable in the growth media, suggesting that loss of piliation in the swarmer- to stalked-cell transition occurs via pilus retraction.

Cancer Res, 1977 Jul, 37(7 Pt 1), 2050 - 6
1,10-Phenanthroline inhibition of lymphoblast cell cycle; Falchuk KH et al.; The effects of the metal-chelating agent, 1,10-phenanthroline (OP), on the cell cycle progression of CCRF-CEM lymphoblasts has been studied by flow microfluorometry . Lymphoblasts were incubated with 2,3-dihydro-1H-imidazo{1,2-b}pyrazole in order to block them in G1-early S . The block was then reversed by incubating the cells in fresh media . Within 2 to 4 hr, approximately 90% of the cells were in S phase and, by 6 hr, approximately 80% were in late S . Aliquots of these latter cells then were incubated with podophyllotoxin to block them in G2-M . These cells divided within 4 hr of reversal of the podophyllotoxin block . Lymphoblast populations in G1-early S, mid-S, or G2-M were then incubated with 4 micronM OP . OP blocked entry of G1 cells into S as well as progression through S but had no effect on progression from G2-M to G1 . The OP effects were reversed by addition of Zn2+, Cu2+, or Fe2+ or by dilution of the chelating agent in the growth media . Incubation of CCRF-CEM lymphoblasts with 1,7-phenanthroline, a nonchelating analog of OP, did not affect the cell cycle . The data indicate that OP reversibly blocks progression of cells from G1 to S and through S by chelation of metals involved in processes essential for those cell cycle events.

Mol Biol (Mosk), 1977 Jul-Aug, 11(4), 757 - 65
{Induction of colicin E1 synthesis in Escherichia coli cells with different concentrations of plasmid DNA}; Khmel' IA et al.; RRelationship between the level of induction of colicin E1 synthesis and the content of plasmid DNA in Escherichia coli K12S (E1) cells was studied . The number of Col E1 DNA copies per cell was found to decrease with growing generation time for different growth media and to increase continuously for the time of synchronous cell division cycle . No apparent relation of the level of spontaneous induction and of induction caused by N-methyl-N'-nitro-N-nitrosoguanidine to the number of Col E1 DNA copies per cell was observed . It is inferred that the content of plasmid DNA in the cells is not among the main factors determining the level of induction of colicin synthesis.

Br J Cancer, 1977 Jul, 36(1), 72 - 7
Sulphated acid mucopolysaccharides in SV40-transformed human cells from normal and mucopolysaccharidosis patients; Webb T; Lines of fibroblasts have been established from normal individuals and from patients diagnosed as suffering from one of the mucopolysaccharidoses or mucopolysaccharide-storage diseases . Transformation of these lines with SV40 virus has been found to reduce their capacity to secrete sulphated mucopolysaccharides into the growth medium . No differences were detected between the individual cell types in their secretory capacity, either before or after viral transformation . A direct relationship was found to exist between the rate of acid mucopolysaccharide production and cell-doubling time . The level of sulphated mucopolysaccharide detected within the cell was also reduced for all cell types after transformation by SV40 . Transformed fibroblasts from mucopolysaccharidosis patients, however, showed a relatively greater reduction in storage capacity than those derived from normal individuals.

Mikrobiologiia, 1977 Jul-Aug, 46(4), 656 - 60
{Oospora lactis strain actively producing lipase}; Shchelokova SS et al.; Morphological, cultural and physiological properties of the fungus Oospora lactis producing lipase are described . The activity of lipase depends on the composition of a growth medium, pH, temperature, the duration of cultivation . Optimum conditions for lipase biosynthesis by the fungus have been found . The strain produces extracellular and endocellular lipases during submerged cultivation in the optimum growth medium at a high rate.

In Vitro, 1977 Jul, 13(7), 450 - 60
Induction of placental alkaline phosphatase in choriocarcinoma cells by 5-bromo-2'-deoxyuridine; Chou JY et al.; Growth of choriocarcinoma cells in the presence of 5-bromo-2'-deoxyuridine (BrdUrd) results in a 30- to 40-fold increase in alkaline phosphatase activity . The effects of BrdUrd is specific for phosphatase with an alkaline pH optimum . The induction by BrdUrd is probably not due to the production of an altered enzyme, since the induced enzyme resembles the basal enzyme in thermal denaturation and kinetic properties . Enzyme induction can be prevented by thymidine but not by deoxycytidine or deoxyuridine . The induction of alkaline phosphatase appears to require incorporation of the BrdUrd into cellular DNA . The presence of BrdUrd in the growth medium is not necessary for alkaline phosphatase induction in proliferating cells containing BrdUrd-substituted genomes . However, enzyme induction and maintenance of the induced levels of alkaline phosphatase in nonproliferating cells containing BrdUrd-substituted DNA requires the presence of the analogues in the medium . The induction of alkaline phosphatase by BrdUrd in probably an indirect process.

N Engl J Med, 1977 Jun 16, 296(24), 1377 - 9
Chilamydia trachomatis infection in patients with acute salpingitis; Mardh PA et al.; We examined the prevalence of Chlamydia trachomatis in the cervix and the fallopian tubes of patients with acute salpingitis . Cycloheximide-treated McCoy cells were used as the growth medium . For purposes of comparison, women with infections confined to the lower genital tract and women without signs of genital infections were also studied . C . trachomatis was isolated from the cervix in 19 of 53 patients with acute salpingitis, in one of 18 lower-genital-tract infections and in none of 12 without signs of genital infection . C . trachomatis was recovered from six of the 20 valid specimens from the fallopian tubes of the patients with acute salpingitis . Our results indicate that chlamydia is a common etiologic agent in acute salpingitis.

J Urol, 1977 Jun, 117(6), 708 - 11
Sterol synthesis in cultured human renal cell cancer; Gonzalez R et al.; Studies on sterol synthesis in cultured human renal cell carcinoma were conducted in an attempt to elucidate the mechanism by which clear cell tumors accumulate cholesterol in the cytoplasm . Cultured renal cell carcinoma requires serum lipoproteins for optimal growth . In some renal cell carcinomas cellular cholesterol content was significantly higher than that present in cultured kidney cells under similar conditions . Renal cell carcinoma synthesizes sterols from labeled acetate . The rate of sterol synthesis is inversely proportional to the levels of exogenous cholesterol in the growth medium, suggesting the presence of a negative feedback mechanism . In addition, the conversion of 27-carbon-atom sterol precursors to cholesterol appears to be slow and inefficient under the presnt conditions . We conclude that an aberrant regulation of cholesterol synthesis cannot be invoked necessarily to explain cholesterol accumulation in renal cell carcinoma.

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