Growth media

J Cell Sci, 1977 Jun, 25, 95 - 102
Preferential inhibition of rDNA transcription by 5-bromodeoxyuridine; Lykkesfeldt AE et al.; On a chemically defined growth medium the degree of substitution of thymidine with 5-bromodeoxyuridine (BUdR) in DNA of Tetrahymena pyriformis was controlled by the concentration of tetrahydrofiolic acid, BUdR and thymidine in the medium . A correlation between the degree of BUdR substitution in DNA and the reduction in rate of total RNA synthesis has been established . It was found that the reduction of total RNA synthesis results from inhibition of transcription of all RNA species which have been measured . However, independent of the degree of BUdR substitution in DNA, a preferential inhibition of the synthesis of 25s and 17s ribosomal RNA was found . It is concluded that the various genes may respond differently to BUdR substitution with respect to transcription.

Int J Radiat Biol Relat Stud Phys Chem Med, 1977 Jun, 31(6), 507 - 18
Influence of a uvrD mutation on survival and repair of X-irradiated Escherichia coli K-12 cells; van der Schueren E et al.; The presence of a uvrD mutation increased the X-ray sensitivities of E . coli wild-type and polA strains, but had no effect on the sensitivities of recA and recB strains, and little effect on a lexA strain . Incubation of irradiated cells in medium containing 2,4-dinitrophenol or chloramphenicol decreased the survival of wild-type and uvrD cells, but had no effect on the survival of recA, recB and lexA strains . Alkaline sucrose gradient sedimentation studies indicated that the uvrD strain is deficient in the growth-medium-dependent (Type III) repair of DNA single-strand breaks . These results indicate that the uvrD mutation inhibits certain rec+lex+-dependent repair processes, including the growth-medium-dependent (Type III) repair of X-ray-induced DNA single-strand breaks, but does not inhibit other rec+lex+-dependent processes that are sensitive to 2,4-dinitrophenol and chloramphenicol.

Genetics, 1977 Jun, 86(2 Pt . 1), 399 - 411
The effects of genotype frequency and population density on fitness differentials in Escherichia coli; Smouse P et al.; Two strains of Escherichia coli K-12, a lac+ wild type and a lac- auxotroph, were grown both as pure and mixed cultures, using a serial transfer procedure . Four different growth media were employed, consisting of the same minimal salts solution, but different total concentrations of the sugars lactose, arabinose, and glucose (in proportions 5:4:1) . Population densities and genotypic frequencies were assayed every 48 hours, at the time of transfer . Population density of the pure lac+ culture was greater than that of the pure lac- culture for all media; this was expected, since the latter cannot utilize lactose . Mixed cultures quickly approached the same density as the corresponding lac+ controls, and the frequency of the lac+ genotype increased steadily for all media . Trajectories of lambda = log (P divided by Q) were strictly nonlinear, indicating a dependence of the selective differential on population density and genotypic frequency . The rate of substitution decreased slightly with increasing sugar concentration, contrary to theoretical expectation . It was speculated that either the generation interval was longer for denser cultures (higher substrate concentrations) of that buildup of organic by-products reduced the selective differential in denser cultures . For a single medium, however, the behavior of completing genotypic strains was reasonably well predicted by theoretical models of frequency and density-dependent selection, the parameters of which may be related to the experimental inputs.

Can J Microbiol, 1977 Jun, 23(6), 690 - 4
Induction of multispored asci in two-spored strains of Saccharomyces cerevisiae by amitrole; Ashraf M et al.; Although growth of two yeast strains characterized by consistent production of two diploid spores per ascus was inhibited in complex presporulation media containing amitrole, a fraction of the cells produced were able to form asci with more than two spores after transfer to acetate sporulation medium . Cells grown in a defined presporulation medium containing amitrole did not acquire this ability . The increase in spore numbers per ascus is attributed either to the induction by amitrole in growth medium of cells with more than one nucleus or to the restoration of normal meioses in the multispored asci.

Jpn J Med Sci Biol, 1977 Jun, 30(3), 125 - 35
Studies on the respiratory system of Aspergillus oryzae . V . Some properties of the respiratory system of mitochondria from mycelia grown in the presence of chloramphenicol; Saito-Wakiyama S et al.; Presence of chloramphenicol in the growth medium for mycelia of Aspergillus oryzae was without effect on the oxidative activity, respiratory control, or P/O ratio of isolated mitochondria . The mitochondria oxidized Krebs cycle intermediates even in the presence of cyanide at the concentration markedly inhibiting the normal mitochondrial oxidation . However, the P/O ratio during the mitochondrial oxidation decreased by about 1.0 on addition of cyanide . The c-type cytochromes, shown to occur in large amounts than in normal mitochondria (Wakiyama and Ogura, 1972), were suggested to act as electron carriers in this cyanide-resistant oxidation . A novel pigment, demonstrated only in the mitochondria prepared from chloramphenicol-treated mycelia by a CO-difference spectrum, was presumed to be the terminal oxidase of the respiration in the presence of cyanide.

J Biol Chem, 1977 May 25, 252(10), 3272 - 6
Induction of 3-hydroxy-3-methylglutaryl coenzyme A reductase in HeLa cells by glucocorticoids; Cavenee WK et al.; The activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase, EC 1.1.1.34) has been demonstrated both in homogenates and microsomes of the S3G strain of HeLa cells . It was increased 8- to 10-fold by the removal of serum from the growth medium . The presence of steroids, specifically of the glucocorticoid series, in the serum-less growth medium elicited an additional 100 to 345% increase over the serum-less control, whereas the addition of N6,O2'-dibutyryl adenosine 3':5'-monophosphate to the medium or dexamethasone to the assay mixture was without any stimulatory effect . Both inductions were blocked by cycloheximide and actinomycin D, suggesting a protein synthesis-dependent elevation of enzyme activity . Glucocorticoids were effective in the induction at concentrations ranging from 10(-6) to 10(-8) M and there was a demonstrated parallel between the magnitude of enzyme induction and glucocorticoid potency . The HMG-CoA reductase activities from steroid-induced and control cultures had identical assay characteristics (pH optima and apparent Km values for both NADPH and HMG-CoA) . This induction of the rate-controlling enzyme of cholesterogenesis occurred despite the observation that glucocorticoids specifically depress the rate of acetate or water, but not mevalonate, incorporation into cholesterol.

Biochemistry, 1977 May 3, 16(9), 1881 - 90
Use of a fluorescent probe to determine the viscosity of LM cell membranes with altered phospholipid compositions; Esko JD et al.; The phospholipid compostition of LM cells grown in tissue culture was altered by substituting ethanolamine for choline in the growth medium . The plasma membrane isolated from cells grown in medium conatining ethanolamine for 83 h had a sixfold increase in the ratio of phosphatidylethanolamine to phosphatidylcholine, the two major phospholipid classes . This was accompanied by small changes in other lipid components of the membrane . There was also a sixfold increase in the amount of triacylglycerols and alkyldiacylglycerols which were not associated with the membrane fraction of the cell . No significant changes occurred in the lipid composition of cells during growth in choline containing medium . The viscosity of plasma membranes was studied in whole cells and isolated membranes using the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene . Plasma membranes isolated from ethanolamine-supplemented cells had greater viscosities than membranes isolated from choline-supplemented cells . When whole cells were labeled with the fluorescent probe, the opposite trend in the apparent membrane viscosity was observed . This was due primarily to the probe penetrating into nonmembranous neutral lipids rather than remaining localized in the surface membrane of the cells . Since the enthanolamine-supplemented cells contained more low viscosity neutral lipids, the whole cells gave an apparently lower viscosity as compared with choline-supplemented cells, thus, measurements carried out on whole cells gave an inaccurate determination of the viscosity of the surface membrane.

Biochemistry, 1977 May 3, 16(9), 1871 - 5
Synthesis and uptake of gangliosides by choleragen-responsive human fibroblasts; Fishman PH et al.; Human fibroblasts, cultured in medium containing 10% fetal calf serum, responded dramatically to choleragen with an increase in cyclic adenosine monophosphate content to greater than 48 times basal levels . Analysis of these cells for gangliosides indicated that the major ganglioside was N-acetylneuraminylgalactosylglucosylceramide (GM3) with trace amounts (less than or equal to 100 pmol/mg of protein) of other gangliosides including GM1, the putative choleragen receptor . Although the cells contained three glycosyltransferases required for ganglioside synthesis, the N-acetylgalactosaminyltransferase activity necessary for the conversion of GM3 to more complex gangliosides was not detected . When the cells were grown in medium containing {14C}galactose or N-acety{3H}mannosamine, however, all of the gangliosides became labeled, indicating that the cells can synthesize complex gangliosides . Although fetal calf serum contains gangliosides including GM1, {3H}GM1 was taken up poorly from the growth medium and uptake at the rate observed could have accounted for less than 2% of the GM1 content of the cells . When the cells were incubated in chemically defined medium containing {3H}GM1 at the concentrations present in fetal calf serum, rapid uptake of the ganglioside occurred and the total GM1 content of the cells increased threefold in less than 3 h . Thus, although the cells are capable of binding exogenous gangliosides, the gangliosides in fetal calf serum are in a form not readily available to the cells.

Mikrobiologiia, 1977 May-Jun, 46(3), 529 - 38
{Comparative cytomorphologic study of strains of Aspergillus terricola in the process of biosynthesis of proteolytic enzymes}; Usenko LI et al.; The cytology and morphology of three strains of Aspergillus terricola were studied in the course of synthesis of proteolytic enzymes . The level of the enzymes in the cultural broth was highest during the growth of the diffused mycelium, and was accompanied with specific cytodifferentiation of the fungal hyphae . The contact between the hyphae of the producing culture and the growth medium is presumed to be important for biosynthesis of the enzymes.

J Lipid Res, 1977 May, 18(3), 379 - 88
Experimentally caused proliferation of lysosomes in cultured BHK cells involving an increase of biphosphatidic acids and triglycerides; Brotherus J et al.; When cultured hamster fibroblasts (BHK 21 cells) were incubated in a synthetic serum-free medium up to 4 days, they developed signs of a progressive proliferation of lysosomes . The cells became filled with vacuoles that contained polymorphic debris and showed acid phosphatase activity . The specific activities of acid protease and acid phosphatase in the cell cultures increased three- to fourfold . The process was accompanied by a marked decrease in the contents of protein, deoxyribonucleic acid, and total phospholipids of the cultures . The concentration of lysobisphosphatidic acid increased during the incubation from about 1.5% to 3-6% of the cellular phospholipids . The concentrations of two related lipids, bisphosphatidic acid and semilysobisphosphatidic acid also increased substantially . The triglyceride content of the cells increased several fold, whereas the concentration of phosphatidylcholine decreased markedly . Lysobisphosphatidic acid did not increase upon induction of vacuolization by exogenous sucrose, nor when there was an accumulation of triglyceride due to addition of oleic acid to the growth medium . These findings suggest that the formation of the bisphosphatidic acids may be specifically linked to the autolysis of the phospholipids of the cellular membranes and the formation of triglycerides associated with this process.

Somatic Cell Genet, 1977 May, 3(3), 263 - 80
Increased intracellular phosphoribosylpyrophosphate and accelerated orotic acid decarboxylation in a mouse cell line resistant to purine and pyrimidine ribonucleosides; May SR et al.; A line of mouse fibroblasts (A9AU-1), originally selected for growth in the presence of 6-azauridine, has been found to be resistant to cytotoxic concentrations of adenosine, guanosine, and thymidine . A9AU-1 cells convert orotic acid to uridine 5'-monophosphate at twice the rate of the A9P line from which the A9AU-1 clone was selected . The resistant cells also excrete purines, synthesized de novo, into the medium at an increased velocity . The average intracellular 5-phosphoribosyl-1-pyrophosphate (PRPP) concentration of the resistant line is 45% higher than that of the parental line . The elevated PRPP concentration is likely to be responsible for both the apparent acceleration of pyrimidine synthesis and the increased excretion of purines into the growth medium; it might also account, by one of the several possible mechanisms, for the resistance of the cells to cytotoxic concentrations of the various nucleosides.

J Protozool, 1977 May, 24(2), 275 - 83
Effects of dimethyl sulfoxide on Tetrahymena pyriformis GL . Fine structural changes and their reversibility; Nilsson JR; Fine-structural changes are induced in Tetrahymena by exposure to 7.5% dimethyl sulfoxide (DMSO) in the presence of growth medium . Some of these changes (nucleolar, mitochondrial, peroxisomal) resemble those seen during starvation, in agreement with the previously reported inhibitory effect of DMSO on food-vacuole formation; however, changes such as helical formations of polyribosomes indicate additional internal actions of the reagent . The effects vary to some extent within the same group of cells, suggesting that sensitivity to the reagent may differ with the stage in the cell cycle . The structural changes induced by a 1-hr exposure to DMSO are reversible, but recovery of the cells after removal of the reagent is slower than that seen after starvation . The observations suggest that the recovery is associated with renewed synthesis.

Mikrobiologiia, 1977 May-Jun, 46(3), 433 - 9
{Mechanism of action of glucose on L-asparaginase synthesis by Escherichia coli bacteria}; Garaev MM et al.; The synthesis of L-asparaginase in Escherichia coli W and E . coli K-12 was almost completely supressed if glucose was added at a concentration of 0.5 per cent to a growth medium . The level of L-asparaginase synthesis decreased by ca . 75 per cent as a result of cyamutations when the bacteria could not produce cyclo-3',5'-AMP (cAMP) . Apparently, a decrease in the intracellular content of cAMP caused by glucose could not be the only factor inhibiting L-asparaginase synthesis . Lactate was found to stimulate L-asparaginase synthesis . Glucose caused the catabolite repression and catabolite inhibition of the components of a system involved in lactate transport . The inhibition of L-asparaginase synthesis by glucose seems to be due, at least partly, to the fact that it prevents the assimilation of lactate by the cells, as well as the utilization of some other compounds which stimulate synthesis of this enzyme.

J Natl Cancer Inst, 1977 May, 58(5), 1515 - 8
Expression of Mason-Pfizer and simian type C viruses in the presence of 5-iododeoxyuridine and dexamethasone; Ahmed M et al.; Production of infectious Mason-Pfizer monkey virus (M-PMV) was enhanced after treatment of the CMMT cell line with 2.5 x 10(-5) M dexamethasone phosphate (DXM) . The reverse transcriptase (RT) activity and infectivity titers of treated culture fluids were enhanced by five- and tenfold, respectively . Along with stimulation of M-PMV synthesis, a simian type C virus (SCV) was also detected by electron microscopic and RT analyses . The SCV was serologically related to the endogenous baboon type C virus . 5-iododeoxyuridine (IUDR) also activated the SCV in the CMMT cell line while significantly inhibiting the production of infectious M-PMV . The activation of endogenous SCV by IUDR or DXM was transitory, since removal of these compounds from the growth medium resulted in the disappearance of SCV buds and the related RT activity; however, low levels of specific viral structural proteins continued to be synthesized intracellularly . Similarly, the enhancement of M-PMV production seen with DXM was lost when the treated cells were subcultured for 2 weeks in the absence of the hormone.

Biochim Biophys Acta, 1977 Apr 18, 466(2), 336 - 46
Qualitative and quantitative variations of membrane lipid species in Acholeplasma laidlawii A; Wieslander A et al.; In Acholeplasma laidlawii A, strain EF 22, the relative amounts of the membrane polar lipids vary as a consequence of different fatty acid supplements to the growth medium . The number of lipid species also varies; a new apolar monoglucolipid containing four fatty acid residues was present only when saturated fatty acids dominated in the growth medium . A new phosphoglucolipid, probably with a glycerophosphoryl-monoglucosyldiglyceride structure, was also found . The most pronounced variations occurred between the two dominating glucolipids, monoglucosyldiglyceride and diglucosyldiglyceride; the former being found in larger amounts when a saturated or a trans-unsaturated fatty acid was present in the medium . The amount of diglucosyldiglyceride decreased accordingly . A qualitative relationship between fatty acid properties and membrane lipid variations was established over a wide fatty acid concentration range . Incorporation of supplied fatty acids reached higher levels than normally found in other acholeplasmas . The ratio between membrane protein and lipids exhibited significant and coherent variations during growth and was to some extent influenced by the fatty acids in the medium . These changes indicate variations in lipid-protein organization in the membranes during growth.

Aust J Biol Sci, 1977 Apr, 30(1-2), 21 - 31
Dithionite reduction in the presence of a tetrapyrrole-containing fraction from the desulfoviridin of Desulfovibrio gigas; Skyring GW et al.; Low-molecular-weight fractions obtained from the desulfoviridin of D . gigas and from the growth medium of Desulfovibrio sp . 10455 promoted the reduction of sodium dithionite to sulphide in the presence of reduced methylviologen . These fractions contained a tetrapyrrole of the isobacteriochlorin type which was not complexed with iron, nor was it complexed with protein . The observations are discussed in relation to the function of sulphite reductases in the sulphate-reducing bacteria.

Appl Environ Microbiol, 1977 Apr, 33(4), 906 - 10
Oxidative coupling of aromatic pesticide intermediates by a fungal phenol oxidase; Sjoblad RD et al.; The soil fungus Rhizoctonia praticola produced an enzyme that accumulated in the growth medium and caused the polymerization of phenolic and naphtholic intermediates of various pesticides . The dialyzed crude enzyme was purified by ion-exhange column chromatography with diethylaminoethyl-cellulose, followed by gel filtration with Sephadex G-200 . The enzyme, a phenol oxidase, was capable of polymerizing 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, and 4-bromo-2-chlorophenol . 1-Naphthol, 2-naphthol, and some of their derivatives formed oligomers or polymers when incubated with the enzyme, but 4-nitrophenol and 2,4-dinitriphenol were not oxidized . Chlorinated and brominated anilines, which are derivatives of herbicides, were not altered by the phenol oxidase from R . praticola, but 4-methoxyaniline was transformed by the enzyme to 2-amino-5-p-anisidinobenzoquinone-di-p-methoxyphenylimine . The formation of polymeric products was determined by mass spectrometric analysis.

Lipids, 1977 Apr, 12(4), 375 - 81
Erucic acid and phospholipids of newborn rat heart cells in culture; Rogers CG; Erucic acid (delta 13-docosenoic acid), labeled with 14C in the 1- or 14-position, was incorporated into fetal calf serum and fed to beating, neonatal rat myocardial cell in culture . Uptake of the docosenoic acid during the first 6 hr of incubation was 41 nM/hr/mg protein in 7-day old cells and 29 nM/hr/mg protein in 14-day old cells . Fifty-seven percent of the 14C-activity was taken up from the medium in 24 hr, of which 77% was in the cells and 23% was unaccounted for . Of the 14C-activity taken up, 26% was in extractable lipid, with two-thirds in neutral lipid and one-third in phospholipid . Within the neutral lipid fraction, 88% of the 14C-activity was present in triglycerides; while in phospholipids, 66% of the 14C-activity was in phosphatidylcholine (PC); 14% in phosphatidylethanolamine (PE); 6% in sphinogomyelin (SPH) and 1% or less in cardiolipin (DPG) . PC had the highest specific activity, followed by SPH and PE . The specific activity of PE was one-half that of SPH when the 14C-erucic acid substrate was labeled at the carboxyl position, but increased to equal that of SPH when the substrate was labeled at the double bond . The fatty acids of PC, PE, and SPH were influenced by erucic acid in the growth medium, but the amounts of each phospholipid were not affected . It is proposed that the altered fatty acid composition associated with incorporation of erucic acid or its metabolites into PC, PE, and SPH may affect integrity and function of heart cell membranes.

J Bacteriol, 1977 Apr, 130(1), 485 - 94
Chemotaxis in Spirochaeta aurantia; Greenberg EP et al.; Cell of Spirochaeta aurantia M1 suspended in isotropic buffer solution swam in nearly straight lines and appeared to spin around their longitudinal axis . Occasionally, cells stopped and flexed, and then resumed translational motility, usually in a different direction . The average cell velocity was 26 micron/s . A quantitative assay for chemotaxis was used to test various chemicals for their ability to attract S . aurantia M1 . The cells exhibited a tactic response toward 5 X 10(-2) M D-glucose between 10 and 35degree C; the optimum response was at 25degree C . At 5 degree C motility was not impaired, but D-glucose taxis was abolished . Chemotaxis toward D-glucose was stimulated by L-cysteine (2 X 10(-4) M) . D-Glucose, 2-deoxy-D-glucose, alpha-methyl-D-glucoside, D-galactose, D-fucose, D-mannose, D-fructose, D-xylose, maltose, cellobiose, and D-glucosamine were effectve attractants for S . aurantia M1 . D-Galactose taxis and D-fucose taxis were induced by the presence of D-galactose in the growth medium . The amino acids tested did not serve as attractants, tgrowing cells of S . aurantia M1 exhibited an aerotactic response.

Biochim Biophys Acta, 1977 Apr 1, 466(1), 148 - 59
Control of fatty acid composition of Acholeplasma laidlawii membranes; Melchior DL et al.; The temperature-dependent pattern of incorporation of palmitate and oleate from the growth medium into Acholeplasma laidlawii membrane lipids correlates with the physical state of the membrane defined by calorimetry . Both the pattern and the state can be changed at will by changing the fatty acid composition of the membrane lipids . The ratio of palmitate to oleate incorporated is independent of temperature when the membrane bilayer is below its transition and fully ordered, but becomes temperature dependent upon the onset of the transition and continues to be temperature dependent when the membrane is above its transition and fully fluid . This behavior is mimicked by the physical binding of palmitate and oleate to bilayers of extracted membrane lipids and to bilayers of lecithin . Selective binding by membranes may provide a means for controlling lipid fatty acid composition without invoking an enzymatic mechanism.

Arch Microbiol, 1977 Apr 1, 112(3), 255 - 61
{Studies on development of the phycomycete Allomyces arbuscula . III . Polysome formation and RNA metabolism during differentiation of gametangia (author's transl)}; Fahnrich P; Polysomes were isolated both from growing gametophytes of Allomyces arbuscula and from gametangia prepared from mycelia at different periods during gametogenesis . Analysis of polysomes by sucrose gradients showed that ribosomes present in the gametangia monosome pool were shifted into polysomes . This shift was found to be correlated with gametangia differentiation . The ribosome distribution remained virtually unchanged during the early stage of gamete formation . In mature gametes and swarming zygotes a low level of polysomes was detected . Labeling of rRNA by 32PO4 demonstrated a de novo synthesis of monosomes throughout the period of gametangia differentiation . No incorporation of 32PO4 was found to be present in ribosomes prepared from gametangia after onset of gamete formation . On the basis of these labeling experiments it is concluded that radioactivity in polysomes extracted from mature gametes and swarming zygotes can be attributed in part to conserved mRNA . Synchronous formation of gametangia was induced by transferring the vegetative mycelia from growth medium into a low salt buffer . Under these conditions the incorporation of either 32PO4 or 3H-uridine into RNA, particularly into rRNA, was found to be markedly decreased . This obviously indicates a shutdown of RNA synthesis . rRNA from induced mycelia examined by polyacrylamide gel electrophoresis was found to be severely degraded . In contrast to this, rRNA isolated from ribosomes of developing gametangia and from gametes exhibited no degradation products . It is suggested that endonucleases cause rRNA hydrolysis in the hyphal cytoplasm during gametangia differentiation . Ribosomes compartmentalized in gametangia seem to be inaccessible to nucleases during the later process for gametogenesis.

J Bacteriol, 1977 Apr, 130(1), 472 - 84
Growth and metabolism of inositol-starved Saccharomyces cerevisiae; Henry SA et al.; Upon starvation for inositol, a phospholipid precursor, an inositol-requiring mutant of Saccharomyces cerevisiae has been shown to die if all other conditions are growth supporting . The growth and metabolism of inositol-starved cells has been investigated in order to determine the physiological state leading to "inositolless death" . The synthesis of the major inositol-containing phospholipid ceases within 30 min after the removal of inositol from the growth medium . The cells, however, continue in an apparently normal fashion for one generation (2 h under the growth conditions used in this study) . The cessation of cell division is not preceded or accompanied by any detectable change in the rate of macromolecular synthesis . When cell division ceases, the cells remain constant in volume, whereas macromolecular synthesis continues at first at an unchanged rate and eventually at a decreasing rate . Macromolecular synthesis terminates after about 4 h of inositol starvation, at approximately the time when the cells begin to die . Cell death is also accompanied by a decline in cellular potassium and adenosine triphosphate levels . The cells can be protected from inositolless death by several treatments that block cellular metabolism . It is concluded that inositol starvation results in a imbalance between the expansion of cell volume and the accumulation of cytoplasmic constituents . This imbalance is very likely the cause of inositolless death.

Mutat Res, 1977 Apr, 43(1), 1 - 10
Alkaline sucrose sedimentation studies of MMS-induced DNA single-strand breakage and rejoining in the wild type and in UV-sensitive mutants of Saccharomyces cerevisiae; Jachymczyk WJ et al.; MMS-induced DNA single-strand breakage and rejoining was studied in the RAD strain and in rad6 and rad21 mutants, both very sensitive to this treatment as compared with the wild type . Alkaline sucrose gradient centrifugation showed that MMS treatment reduced the molecular weight of DNA in the RAD strain and in rad6 and rad21 mutants to the same extent . Four hours of post-incubation in synthetic growth medium after treatment with a dose of 0.4% MMS which reduces cell survival of RAD, rad21 and rad6 to 50, 20 and less than 0.01%, respectively, resulted in a significant increase in the molecular weight of DNA in the wild type, but in only slight increase in mutant strains . When the strains were exposed to a lower dose of MMS (0.04%) which led to 100% survival of RAD and 50 and 20% survival of rad21 and rad6, respectively, wild-type DNA sedimented to the position of control DNA, while in both mutants the increase in molecular weight of DNA was less pronounced.

Appl Environ Microbiol, 1977 Apr, 33(4), 758 - 61
Fungal growth on C1 compounds: quantitative aspects of growth of a methanol-utilizing strain of Trichoderma lignorum in batch culture; Tye R et al.; A study was made of some salient parameters that influence growth of the methanol-utilizing fungus Trichoderma lignorum growing in batch culture on a minimal medium containing methanol as the sole source of carbon . Maximum cell yield was recorded at the expense of 1.58 g of methanol per liter . Inhibition was observed with methanol concentrations in excess of 4.7 g/liter . The optimum temperature for fungal growth was 23 degrees C . Growth of the fungus was directly proportional to an inorganic nitrogen concentration up to 0.2 g of NH4NO3 per liter . No inhibition of growth occurred at any concentration of NH4NO3 up to 11 g/liter . The pH of the growth medium decreased from 7.0 to 3.5 during growth of the fungus on methanol, which may have been due, in part, to the accumulation of trace amounts of organic acids in the growth medium . An analysis of the commercial potential of the fungus, as a source of edible protein, indicated that the strain of methanol-utilizing T . lignorum used was uneconomical in terms of the yield and the specific growth rate.

J Bacteriol, 1977 Apr, 130(1), 464 - 71
Morphology of Ureaplasma urealyticum (T-mycoplasma) organisms and colonies; Razin S et al.; The morphology of Ureaplasm urealyticum in broth cultures was studied by phase-contrast microscopy . Most organisms appeared singly or in pairs . Long filaments and long chains of cocci, common in classical mycoplasma cultures, were not observed . On solid medium, U . urealyticum produced "fried-egg" colonies which developed according to the scheme suggested by Razin and Oliver (J . Gen . Microbiol., 1961) for the morphogenesis of the classical mycoplasma colonies . The formation of the peripheral zone of the colonies followed that of the central zone only when growth conditions were adequate, Hence, the appearance of peripheral zones, and consequently the larger colony size, can be taken as an indicator of improved growth conditions . Incubation in an atmosphere of 100% CO2 resulted in significantly larger colonies than in an atmosphere of N2, O2, or air . CO2 acts as a buffer, keeping the pH at the optimal range for Ureaplasma growth (pH 6.0 to 6.5) in the presence of the ammonia produced from the urea hydrolyzed by the organisms . The addition to the medium of 0.01 M urea together with 0.01 M putrescine enabled better growth than with urea alone . Small amounts of phosphate improved growth in an atmosphere of CO2, apparently fulfilling a nutritional role . Under nitrogen, higher phosphate concentrations were required for good growth, apparently serving as a buffer as well as a nutrient . Sodium chloride and sucrose which had been added to increase the tonicity of the medium inhibited growth above 0.1 M . An increase in the agar concentration above 2% resulted in decreased colony size . Likewise, prolonged drying of the agar plates caused a marked decrease in colony size, mostly affecting the peripheral zone . The addition of both urea and putrescine to the growth medium and incubation in a humidified CO2 atmosphere are recommended for improved growth and formation of fried-egg colonies of U . ureaplyticum on agar . It must be emphasized that these experiments were carried out with a laboratory-adapted strain.

J Bacteriol, 1977 Apr, 130(1), 297 - 302
Localization of enzymes in Ureaplasma urealyticum (T-strain mycoplasma); Masover GK et al.; Ureaplasma urealyticum cells were lysed by osmotic shock or by digitonin . The membrane fraction contained four to ten times as much protein as the cytoplasmic fraction . These values are in large excess of those reported for classical mycoplasmas, suggesting that the Ureaplasma membrane fraction was heavily contaminated with proteins derived from the growth medium . The U . urealyticum urease activity was localized in the cytoplasmic fraction, whereas the adenosine triphosphatase activity was localized in the membrane fraction . Significant urease activity could be detected also in nonviable cells . Urea, at concentrations above 0.25 M, was mycoplasmastatic to Acholeplasma laidlawii, Mycoplasma hominis, and U . urealyticum, so that the Ureaplasma urease did not afford preferential protection against urea toxicity . The intracellular localization of the urease would be expected to release ammonia from urea in the cytoplasm . The ammonia will take up protons to become ammonium ions . It can be hypothesized that the intracellular NH4+ plays a role in proton elimination or acid-base balance, which might be coupled to an energy producing ion gradient and/or transport mechanisms.

J Bacteriol, 1977 Apr, 130(1), 292 - 6
Effects of carbon dioxide, urea, and ammonia on growth of Ureaplasma urealyticum (T-strain mycoplasma); Masover GK et al.; By use of a simple device for continuous CO2 gassing of Ureaplasma urealyticum cultures growing in a liquid medium, we have been able to separate some of the effects of urea, CO2, ammonia, and pH on growth . The CO2 acted as a superior buffer in the pH range 5.7 to 6.8, which is optimal for Ureaplasma growth . It was, therefore, possible to observe the effect of repeated additions of urea to the culture without alkalinization of the growth medium . We found that the repeated additions of urea did not enhance Ureaplasma growth, and the resultant accumulation of ammonium ions (greater than 2,000 microng/ml) did not cause more rapid death under these conditions . By abruptly changing the gaseous environment from CO2 to N2, it was possible to cause a rapid pH change in the culture to a value above 8.0 . This resulted in a more rapid death of the organisms.

Biotechnol Bioeng, 1977 Apr, 19(4), 539 - 54
Growth characteristics of Candida utilis on volatile substrate in a multistage tower fermentor; Paca J et al.; The influence of increasing ethanol concentration in the feed on growth and physiological activity of the yeast Candida utlis was studied . The measurements were made at steady states of continuous culture under constant values of dilution rate, temperature, and pH in all stages of the fermentor; Synthetic ethanol was used as the sole source of carbon and energy in the concentration range 10-100 g/liter . The maximum biomass concentration in the effluent and maximum productivity was achieved at 75 g ethanol/liter in the feed . In respect to ethanol losses in the outlet and biomass yield, the optimum ethanol concentration in the input of the growth medium was found to be about 50 g/liter using a four-stage system.

Biochemistry, 1977 Mar 8, 16(5), 944 - 53
Equilibration of fucosyl glycoprotein pools in HeLa cells; Yurchenco PD et al.; The pool sizes, label equilibration times, and specific radioactivity relationships of fucosyl glycoproteins and precursors have been examined in exponentially growing HeLa S3 cells (generation time about 23 h) using a quantitative radioisotopic approach . The specific radioactivity of the precursor GDP-fucose (pool size 0.52 +/- 4% nmol/10(7) cells) equilibrates with radioactive fucose in the medium in about 1 h . 10(7) cells contain 5.3 +/- 16% nmol of glycoprotein fucose of which 96-98% resides in or on the cell surfaces and is equilibrated isotopically within 22 h of labeling; 2% or less is in an internal pool, some of which is precursor to plasma membranes and some of which is released as soluble glycoprotein directly to the medium without random mixing with the plasma membrane glycoprotein . Because we cannot rule out the presence of internal free fucose, 2% of the total glycoprotein fucose could be in the degradative pathway being recycled internally before release of free fucose . In rate terms and in a particular culture where 10(7) cells contained 4.4 nmol of glycoprotein fucose, a total of 11.1 nmol of glycoprotein fucose is synthesized per generation (9-11% of the total cell glycoprotein fucose/h) . Of this, 2.5 nmol of glycoprotein fucose per generation is released directly into the growth medium without mixing with the plasma membrane glycoprotein fucose . The small internal pool feeding glycoprotein fucose to the plasma membrane does so at the rate of 8.6 nmol/10(7) cells per generation, 4.2 nmol per generation of which, after mixing with the plasma membrane glycoprotein fucose, is ultimately released into the growth medium, 75-80% as free frucose . This release process is independent of cell density and the presence of serum in the growth medium.

Mikrobiologiia, 1977 Mar-Apr, 46(2), 304 - 10
{Causes of degeneration of cultures of Thermoactinomyces vulgaris}; Kokina VIa et al.; Passage of cultures of Thermoactinomyces vulgaris on a peptone-maize medium causes their degeneration which is manifested in an impaired formation of the sporulating aerial mycelium, and in an increase of the amount of non-germinating spores in populations . The process of degeneration depends on the following conditions: the location of the inoculated material (spores) on the surface of a solid growth medium, which is determined by the technique of inoculation; the state of the spores (degeneration is accelerated if the spores were not activated with low temperatures); the quality of the growth medium.

Mikrobiologiia, 1977 Mar-Apr, 46(2), 252 - 6
{Influence of the nutrient medium on the total lipid fatty acid composition of Actinomyces canosus}; Koval'chuk LP et al.; GLC was used to study the composition of endocellular fatty acids of Actinomyces canosus 89 grown on a chemically defined medium and on a complex medium to which various components were added . Total lipids of the culture contain saturated and unsaturated fatty acids, from C13 to C18, with one or two double bonds . Addition of components to the medium stimulated the biosynthesis of myristic, stearic, oleic, and linoleic fatty acids . Changes in the composition of the growth medium modify the ratio between saturated and unsaturated fatty acids of total lipids, increasing the content of unsaturated fatty acids due to a higher rate of synthesis of linoleic and oleic fatty acids . An increase in the content of unsaturated fatty acids is a positive factor because these acids are involved in important physiological functions of both this organism and other living organisms.

Cell Tissue Kinet, 1977 Mar, 10(2), 127 - 35
Relationship of nutritional factors to in vitro tumor cell growth and cytotoxicity produced by cytosine arabinoside; Momparler RL et al.; The in vitro relationship between nutritional factors, proliferative status of tumor cells, and the cytotoxic action of cytosine arabinoside (ara-C) was investigated . The reduction in the concentration of only one essential amino acid, L-isoleucine, in the growth medium of A(T1)C1-3 hamster fibrosarcoma cells decreased DNA synthesis in this cell population and slowed the rate of progression of G1 phase cells into S phase of the cell cycle . The complete omission of isoleucine from the growth medium blocked the progression of G1 phase cells into S phase and prevented the cytotoxic action of ara-C . The addition of isoleucine to the isoleucine-deprived cells permitted these cells to enter the S phase and restored their sensitivity to the cytotoxic action of ara-C . When G1 phase cells were placed in a medium containing reduced levels of all the amino acids and vitamins there was a prolongation of the G1 phase . Since medium with low levels of amino acids produced a delay in the entry of G1 phase cells into the S phase, the time interval in which these cells were most sensitive to the cytotoxic action of ara-C was different for G1 phase cells placed in medium with adequate levels of all the amino acids . These in vitro data indicate that nutritional factors can markedly effect the proliferation of tumor cells and the cytotoxic action of ara-C.

J Biol Chem, 1977 Feb 25, 252(4), 1257 - 63
Novel enzymic machinery for the metabolism of oxalacetate, phosphoenolpyruvate, and pyruvate in Pseudomonas citronellolis; O'Brien R et al.; The metabolic pathways for the interconversion of oxalacetate, phosphoenolpyruvate, and pyruvate in Pseudomonas citronellolis form an interlocking system (Scheme 1) that would appear to require complex regulatory mechanisms to permit a proper flow of metabolites through the pathways and to prevent futile cycling . Oxalacetate decarboxylase (I in Scheme 1), P-enolpyruvate synthase (II), P-enolpyruvate carboxylase (III), and pyruvate kinase (V) are constitutive enzymes in this organism . Pyruvate carboxylase (VI) is inducible and has its highest activity in cells grown on glucose or lactate, moderate activity in cells grown on acetate, citrate, or glutamate, and virtually no activity in aspartate-grown cells . P-enolpyruvate carboxykinase (IV) was not detected . The presence of these five enzymes in a single cell has not been previously reported . In Scheme 1, three futile cycles are possible: the simultaneous operation of Reactions I and VI; of Reactions II and V; or of I, II, and III . An examination of the regulatory properties of the individual enzymes after partial purification offers support for the hypothesis of an intricate regulatory system . Oxalacetate decarboxylase (I) is inhibited by acetyl-CoA; phosphoenolpyruvate carboxylase (III) is activated by acetyl-CoA and ADP and inhibited by aspartate; phosphoenolpyruvate synthase (II) is inhibited by 5'-AMP and phosphoenolpyruvate; and pyruvate kinase (V) is activated by 5'-AMP and 2 keto, 3-deoxy,6-phosphogluconate and inhibited by ATP . The presence of metabolites with reciprocal but reinforcing functions is noteworthy . As an example, acetyl-CoA both inhibits the breakdown of oxalacetate and stimulates its formation . Only pyruvate carboxylase appears to be regulated by the carbon substrates of the growth medium.

J Biol Chem, 1977 Feb 10, 252(3), 878 - 82
Metabolic regulation of aminoacyl-tRNA synthetase biosynthesis in bakers' yeast; Johnson RC et al.; The specific activities of 15 aminoacyl-tRNA synthetases in Saccharomyces cerevisiae were measured after growth under a variety of conditions that produced a range of cell-doubling times . The specific activity of each synthetase increased as cell-doubling time decreased . Control experiments eliminate the possibility that these results are due to preferential recovery of synthetases, or to the presence of activators in the faster growing cultures or inhibitors in the slower growing ones . These observations run counter to the expectation that synthetases in bacteria and yeast are negatively regulated by free amino acids, or, more likely, by aminoacyl-tRNA . In fact, as the growth medium was enriched, generation times decreased, and synthetase and aminoacyl-tRNA levels increased . It is suggested that cytoplasmic aminoacyl-tRNA synthetases may be more or less coordinately controlled such that their response to growth follows the pattern observed for ribosome production and RNA synthesis . This suggests the possibility of coordinated response of genes for components of the protein synthetic apparatus.

Arch Microbiol, 1977 Feb 4, 112(1), 57 - 9
The cell content and secretion of water-soluble vitamins by several freshwater algae; Aaronson S et al.; Three green algae, Chlamydomonas reinhardii, Chlorella vulgaris and Scenedesmus obliquus, and one blue-green alga, Anabaena cyclindrica, were grown in chemically defined media . All the algae examined contained folates, beta-carotene and vitamins C and E; several of the B-vitamins and vitamin A were found in varying amounts in some but not in all the algae examined . All the green algae secreted significant amounts of folate and biotin and all but Scenedesmus secreted pantothenate into their growth medium; Anabaena secreted folate and pantothenate.

J Gen Microbiol, 1977 Feb, 98(2), 587 - 93
The effect of growth and urea concentration on ammonia production by a urea-hydrolysing mycoplasma (Ureaplasma urealyticum); Masover GK et al.; The rate of accumulation of ammonium ion in cultures of Ureaplasma urealyticum was independent of the growth rate and of the initial urea concentration above 0-025% in the medium, although the quantity of ammonium ion accumulating did depend on the initial urea concentration . Ammonium ions accumulated at a similar rate in U . urealyticum cultures of both rapidly and slowly growing organisms . Viable but non-growing ureaplasmas also produced ammonia in complete medium at a lower temperature than usual (25 degrees C) or in an inadequate growth medium at 37 degrees C . The rate of ammonium ion accumulation in a dying culture depended on the number of viable organisms present; this is relevant to diagnostic methods for ureaplasms which depend on detecting ammonia colorimetrically.

J Bacteriol, 1977 Feb, 129(2), 866 - 73
Control of arginine utilization in Neurospora; Weiss RL et al.; The response of Neurospora to changes in the availibility of exogenous arginine was investigated . Upon addition of arginine to the growth medium, catabolism is initiated within minutes . This occurs prior to expansion of the arginine pool or augmentation of catabolic enzyme levels . (Basal levels are approximately 25% of those found during growth in arginine-supplemented medium.) Catabolism of arginine is independent of protein synthesis, indicating that the catabolic enzymes are active but that arginine is not available for catabolism unless present in the medium . Upon exhaustion of the supply of exogenous arginine, catabolism ceases abruptly, despite an expanded arginine pool and induced levels of the catabolic enzymes . The arginine pool supports protein synthesis until the cells regain their normal capacity for endogenous arginine synthesis . These observations, combined with the known small level of induction of arginine catabolic enzymes, non-repressibility of most biosynthetic enzymes, and vesicular localization of the bulk of the arginine pool, suggest that compartmentation plays a significant role in controlling arginine metabolism in Neurospora.

J Cell Physiol, 1977 Feb, 90(2), 233 - 40
Differential effects of inhibitors of cell division upon the growth stimulating activities of insulin and serum in nutritionally depleted human and mouse cells; Kamely D; Cultured mouse and human cells were arrested in their growth by artificially depriving them of phosphate . The quiescent cells could be stimulated to synthesize DNA and to divide by addition to the growth medium of insulin, dialyzed serum and/or the full concentration of phosphate . In order to gain insight into mechanisms by which insulin and serum stimulate growth, the inhibitory effects of antimitotic agents were examined . Of the inhibitors tested, vinblastine and cytocalasin B abolished the growth promoting activity of insulin, while colchicine inhibited the activity of both serum and insulin . The present results suggest that insulin-stimulated growth is meciated by a different path way than serum-stimulated growth and is sensitive to mechanisms that occur at various times prior to insulin addition.

Infect Immun, 1977 Feb, 15(2), 510 - 7
Evaluation of experimentally induced Fusobacterium necrophorum infections in mice; Conlon PJ et al.; Two strains of mice, Swiss Webster and DBA/2Cr, were injected intraperitoneally or intravenously with varying dosages of Fusobacterium necrophorum . The ability to eliminate the infection was assessed by quantitative enumeration of the organisms present in the blood, liver, and spleen, Three- to 4-week-old DBA/2Cr mice were highly resistant to both routes of injection . The intraperitoneal injection of older mice failed to demonstrate a dose-effect relationship whereas an intravenous injection of as few as 10(4) cells of F . necrophorum produced progressively necrotic leg abscesses, apparently involving the lymphonodus ischiadicus which filters the site of injection . Mortality was increased with sensitization by a previous sublethal injection . Also, an ethanol-killed cell vaccine delayed the onset of lethal infection, whereas repeated sublethal live cell injections provided nonspecific protection since mice vaccinated with the growth medium were equally protected . The development of leg abscesses after intravenous injection visibly demonstrated the pathogenicity of F . necrophorum and may provide a suitable model for the evaluation of vaccines and the effectiveness of antibiotics.

J Bacteriol, 1977 Feb, 129(2), 798 - 802
Developmentally induced autolysis during fruiting body formation by Myxococcus xanthus; Wireman JW et al.; The developmental events during fruiting body construction by the myxobacterium M . xanthus is an orderly process characterized by several sequential stages: growth leads to aggregation leads to formation of raised, darkened mounds of cells leads to autolysis leads to myxospore induction . The temporal sequence of autolysis followed by myxospore induction is consistent with the interpretation that developmental autolysis provides essential requirements for the surviving cells to induce to myxospores . At intermediate developmental times on agar plates a fraction of the cell population is irreversibly committed to lyse; i.e., lysis continues in liquid growth medium or in magnesium-phosphate buffer . Lysis is cell concentration independent and is therefore likely to be by an autolytic mechanism . The lysis sequence can be preliminarily characterized as having an early stage during which deoxyribonucleic acid synthesis continues and a later irreversible stage during which deoxyribonucleic acid synthesis does not occur . Irreversible lysis in liquid growth medium or in magnesium-phosphate buffer is initiated on agar plates during nutrient deprivation and such lysis results in the induction of a fraction of the population to myxospores . This induction is dependent upon the concentration of lysis products, thus providing evidence that developmentally induced autolysis is required for myxospore induction.

J Cell Physiol, 1977 Feb, 90(2), 307 - 20
A serum factor requirement for the passage of cultured Vero cells through G2; Engelhardt DL et al.; When Vero cells, a line derived from and African Green Monkey kidney, are grown under conditions where the saturation density is limited by serum, they deplete the growth medium of a factor necessary for cell division . The factor is a component of serum . When Vero cells are plated at low density (2 X 10(4)/cm2) in this depleted growth medium (after dialysis against serum-free Dulbecco's Modified Eagle's Medium) they initiate an unbalanced program of growth . Protein synthesis proceeds at the same rate as parallel cells in fresh serum, and and the cells accumulate protein as a function of time . DNA synthesis is also initiated in these cells, and the amount of DNA per cell increases for the next four days plating . However the cells quickly stop dividing . Measurements of DNA per cell using microspectrofluorometry show that the cells are accumulating in the late S and G2 period during this time . Thus we conclude that these cells cannot pass through a transition point in G2 . When fresh serum is added to cells after three days in depleted growth medium, they divide before they begin to synthesize DNA . This further confirms that they are in late S and G2 . Cell division is promoted in Vero cells in depleted growth medium by bovine fetuin, and to a lesser extent by bovine albumin . Cell division is not promoted by insulin, hydrocortisone, dexamethasone, linolenic acid, calcium, and typsin inhibitor form ovomucoid . From these data we conclude that transit through G2 requires the prescence of an extracellular factor.

Biochem J, 1977 Feb 1, 161(2), 357 - 70
Solubilization, partial purification and properties of N-methylglutamate dehydrogenase from Pseudomonas aminovorans; Bamforth CW et al.; 1 . Extracts of amine-grown Pseudomonas aminovorans contained a particle-bound N-methylglutamate dehydrogenase (EC 1.5.99.5) . The enzyme was not present in succinate-grown cells, and activity appeared before growth began in succinate-grown cells which had been transferred to methylamine growth medium . 2 . Membrane-containing preparations from methylamine-grown cells catalysed an N-methylglutamate-dependent uptake of O2 or reduction of cytochrome c, which was sensitive to inhibitors of the electron-transport chain . 3 . N-Methylglutamate dehydrogenase activity with phenazine methosulphate or 2,6-dichlorophenol-indophenol as electron acceptor could be solubilized with 1% (w/v) Triton X-100 . The solubilized enzyme was much less active with cytochrome c as electron acceptor and did not sediment in 1 h at 150000g . Solubilization was accompanied by a change in the pH optimum for activity . 4 . The solubilized enzyme was partially purified by Sepharose 4B and hydroxyapatite chromatograpy to yield a preparation 22-fold increased in specific activity over the crude extract . 5 . The partially-purified enzyme was active with sarcosine, N-methylalanine and N-methylaspartate as well as with N-methylglutamate . Evidence suggesting activity with N-methyl D-amino acids as well as with the L-forms was obtained . 6 . The enzyme was inhibited by p-chloromercuribenzoate, iodoacetamide and by both ionic and non-ionic detergents . 2-Oxoglutarate and formaldehyde were also inhibitors . 7 . Kinetic analysis confirmed previous workers' observations of a group transfer (Ping Pong) mechanism . 8 . Spectral observations suggested that the partially purified preparation contained flavoprotein and a b-type cytochrome . 9 . The role of the enzyme in the oxidation of methylamine is discussed.

Infect Immun, 1977 Feb, 15(2), 518 - 26
Levan and levansucrase of Actinomyces viscosus; Pabst MJ; A levansucrase was demonstrated in the growth medium and in association with the cell surface of Actinomyces viscosus . The amount of enzyme produced relative to cell density is not significantly affected by the growth conditions . Sugar alcohols inhibit growth of the cells . The levansucrase hydrolyzes sucrose to produce free glucose and levan; some free fructose is also formed . There is no requirement for cofactors . The Km for sucrose is 12 mM . A variety of heavy metal ions and two disaccharides, lactose and cellobiose, inhibit the enzyme . The levansucrase was purified to homogeneity and has a specific activity of 90 micronmol of glucose release per min per mg . The enzyme has a molecular weight of 220,000 and is composed of subunits of molecular weight 80,000 . The levan product contains both beta(2 leads to 1) and beta(2 leads to 6) linkages . The enzyme remains tightly bound to the levan product, resulting in the formation of high-molecular-weight polymer on the order of 10(8) daltons . The possible role of the levan and levansucrase of A . viscosus in the pathogenesis of periodontal disease is discussed.

J Immunol Methods, 1977, 17(3-4), 211 - 6
A simple technique for studying immunoglobulin synthesis by normal and malignant plasma cells in vitro; Pritchard S et al.; Plasma cells from human marrows are saturated with C-14 labelled amino acids, harvested and recultured in unlabelled growth medium . The appearance of radioactivity in the growth medium then provides a simple and rapid measure of protein synthesis . The secreted radio-labelled material is characterized by isoelectric focusing and autoradiography in acrylamide gels, a technique which has advantages over established serological methods.

J Supramol Struct, 1977, 6(2), 179 - 89
Role of the membrane potential in serum-stimulated uptake of amino acid in a diploid human fibroblast; Vilereal ML et al.; The Na+-dependent accumulation of alpha-aminoisobutyric acid (AIB), measured in normal growing and quiescent (serum-deprived) HSWP cells (human diploid fibroblast), was found to be twofold higher (AIB/in/AIBout = 20-25) under the normal growing conditions . Serum stimulation of quiescent cells increases their AIB concentrating capacity by approximately 70% within 1 hr . These observations suggest that the driving forces for AIB accumulation may be reversibly influenced by the serum concentration of the growth medium . Addition of valinomycin (Val) to cells preequilibrated with AIB causes an enhanced accumulation of AIB, suggesting that the membrane potential can serve as a driving force for AIB accumulation . After preequilibration with AIB in 6 mM K+, transfer to 94 mM K+ with Val results in a marked and rapid net loss of AIB . The effect of Val on the accumulation of AIB is greatest in quiescent cells, with the intracellular AIB concentrations reaching those seen both in Val-stimulated normal cells and in Val-stimulated serum-stimulated cells . By adjusting {K+}0, in the presence of Val, the membrane potential of growing cells can be matched to that of quiescent cells or vice versa . When this is done, the two accumulate AIB to the same extent . Hence the AIB accumulating capacity is characteristic of the membrane potential rather than of the growth state . In summary, these data suggest that the accumulation of AIB in HSWP cells is influenced by changes in membrane potential and that a serum-associated membrane hyperpolarization could be responsible for the increased capacity for AIB accumulation in serum-stimulated cells.

Eur J Biochem, 1977 Jan, 72(2), 385 - 92
Fate of histone messenger RNA in synchronized HeLa cells in the absence of initiation of protein synthesis; Stahl H et al.; The fate of cytoplasmic histone mRNA was studied under conditions in which initiation of protein synthesis in synchronized HeLa cells is S phase was blocked by increasing the osmolarity of the growth medium with NaCl . In contrast to the interruption of DNA replication with hydroxyurea, which results in an exponential degradation of translatable histone mRNA with a half-life of about 10-13 min, blocking the initiation of protein synthesis leads to only a marginal loss of biologically active histone mRNA in the cytoplasm . When the initiation of protein synthesis was interrupted by treating cells with 150 mM NaCl, 40-50% of the total cytoplasmic histone mRNA previously translated in polyribosomes appears in the cytoplasm integrated into mRNA-protein particle(s) sedimenting between 15 S and 30 S . On the other hand, in untreated S-phase cells or in cells blocked with hydroxyurea only 3-6% of the total translatable histone mRNA is found in the cytoplasm not bound to ribosomes or their subunits . In addition, the degradation of histone mRNA in hydroxyurea-blocked S-phase cells is prevented when the initiation of protein synthesis is inhibited with NaCl . These studies clearly indicate that the inhibition of initiation of protein synthesis per se is not the cause for the rapid degradation of cytoplasmic histone mRNA observed when DNA replication is turned off and that the inactivation of these mRNAs is a process dependent on continuous protein synthesis.

J Supramol Struct, 1977, 6(4), 571 - 7
Sialic acid uptake by BHK cells and subsequent incorporation into glycoproteins and glycolipids; Hirschberg CB et al.; BHK cells can be grown in the presence of growth medium to which radiolabeled sialic acid has been added . After 24 h, 85 percent of the radioactivity in the cells is covalently bound to glycoproteins and glycolipids . No metabolism of the radiolabeled sialic acid could be detected.

Arch Virol, 1977, 54(4), 333 - 43
Persistent infection of BHK21/WI-2 cells with rubella virus and characterization of rubella variants; Sato M et al.; Persistently infected cell lines of BHK21/WI-2 cells have been established by infection with the wild type rubella virus strain M-33 . These cell lines, BHK-MP1 and BHK-MP2, showed immunity-like resistance to superinfection with M-33 virus at both 34 degrees and 39.5 degrees C . They also showed intrinsic interference with the replication of Newcastle Disease Virus at 34 degrees C but not at 39.5 degrees C . They released a small number of infectious virus particles which were temperature sensitive variants, being able to form plaques at 34 degrees C, but not at 39.5 degrees C on BHK21/WI-2 and on its derivative, BSR . When BHK-MP1 cells were cultured at 34 degrees C in growth medium containing 10--20 microgram/ml of 5-bromodeoxyuridine (BudR) there was a 5- to 10-fold increase in infectious virus in the medium as compared with the untreated controls . Mitomycin C (0.5 microgram/ml) treatment for 7 hours likewise stimulated the release of virus from these cells . The enhancement of viral release by BudR was completely blocked by pretreatment with actinomycin D (5 microgram/ml) for 3 hours prior to BudR treatment . Since the variant can be induced by these prophage inducers and inhibited by actinomycin D it is suggested that the viral genome is converted to a DNA provirus which is analogous to the lysogenic state of bacteriophage.

Natl Inst Anim Health Q (Tokyo), 1977 Summer, 17(2), 54 - 7
Chicken kidney cell culture in medium without serum; Yamaguchi S et al.; When chicken kidney cell (CKC) culture in a petri dish was prepared in medium with or without serum and incubated in a humidified incubator at 38 degreesC with no addition of CO2, monolayers of CKCs were formed completely on the 5th day of cultivation . Growth medium used for CKC culture was Eagle's minimum essential medium containing 0.3% of dehydrated tryptose phosphate broth . The number of cells in both cultures prepared in medium with or without serum was the same when measured on the 5th day of cultivation . Monolayers of CKC culture prepared in medium with or without serum were maintained up to 21 days of cultivation, while maintenance medium was changed every 4th day . The time of appearance and degree of cytopathic effect, plaque-forming ability, and propagation of some avian viruses were similar in both cultures prepared in medium with or without serum.

Genetics, 1977 Jan, 85(1), 35 - 54
The effect of ochre suppression on meiosis and ascospore formation in Saccharomyces; Rothstein RJ et al.; The effect of altered tyrosyl-tRNAs on the developmental process of sporulation was examined . Mutations in eight independent loci resulting in tyrosine-inserting nonsense suppressor were tested for their effects on sporulation . Different levels of inhibition were found ranging from SUP3-omicron, which caused the greatest reduction of sporulation (7-17% of wild type), to SUP11-omicron which caused no reduction in sporulation . Since the SUP3-omicron mutation exhibited the greatest effect, it was studied in detail . Although SUP3-omicron is a dominant nonsense suppressor, its effect on sporulation is recessive . Expression of the sporulation deficiency is dependent upon the stage of transfer from glucose growth medium (i.e., log, early stationary, etc.) to sporulation medium . SUP3-omicron/SUP3-omicron diploid cells transferred from log or early stationary phase are capable of sporulation, whereas cells transferred after early stationary phase (i.e., after adaptation to respiration) exhibit poor sporulative ability . Sporulation events were examined under restrictive conditions to observe those events completed by SUP3-omicron/SUP3-omicron diploids . The early events of sporulation occur in these cells . Later events are completed by progressively fewer cells . Premeiotic DNA synthesis occurred in approximately 40% of the cells, nuclear segregation occurred in 20%, and finally, only 2% formed asci . The fact that fewer late-sporulation events occur under restrictive conditions can be explained by increased efficiency of suppression.

J Gen Microbiol, 1977 Jan, 98(1), 177 - 86
Fluctuations in buoyant density during the cell cycle of Escherichia coli K12: significance for the preparation of synchronous cultures by age selection; Poole RK; The buoyant densities of Escherichia coli K12 were investigated by isopycnic centrifugation in gradients of colloidal silica (Ludox) and polyvinylpyrrolidone . Bacteria from an exponential culture in a defined medium supplemented with hydrolysed casein banded at densities between 1-060 and 1-115 g ml-1; the mean density was 1-081 g ml-1 . At the higher densities, two populations of cells were present: smaller cells were approximately twice as numerous as, and half the modal volume of, the population of larger cells . A homogeneous population of cells of intermediate volume equilibrated in the least dense region of the density band . Synchronous cultures were established by inoculating cells selected from the most or least dense regions of the band into spent growth medium . The results are consistent with a fluctuation between maximal density at cell birth and division, and minimal density near the middle of the cell cycle . In synchronous cultures prepared by continuous-flow age selection, the first division occurred after a period that was significantly shorter than the length of subsequent cell cycles . Cells selected by this procedure were of similar mean density to those in the exponential culture but were more homogeneous with respect to size . The possibility that the smallest (and densest) cells in an exponential culture are retained in the rotor, and are thus excluded from the synchronous culture, is discussed.

Antonie Van Leeuwenhoek, 1977, 43(2), 153 - 67
ATP formation associated with fumarate and nitrate reduction in growing cultures of Veillonella alcalescens; de Vries W et al.; Molar growth yields, fermentation balances and enzyme activities were measured in Veillonella alcalescens grown anaerobically with different substrates in the absence or presence of fumarate or nitrate . The molar growth yields on malate (14.3 g dry wt bacteria/mole substrate) and citrate (19.3) were higher than that on lactate (8.6) . The molar growth yield on lactate was increased to 15.5 or 19.8 by the addition of fumarate or nitrate, respectively, to the growth medium, and the molar growth yield on citrate was increased to 25.3 by addition of nitrate . Active growth on pyruvate was only observed in the presence of nitrate, and the molar growth yield was 25.5 . From fermentation balances and fermentation systems similar YATP values (g dry wt bacteria/mole ATP) were calculated for all substrates or mixtures of substrates assuming that one mole of ATP is generated at the electron transport from pyruvate, NADH and NADPH to nitrate or fumarate whereas ATP is not produced in the electron transport from lactate to fumarate or nitrate, and, therefore, this assumption was considered to reflect the actual situation . The mean YATP value at a doubling time of 1 h was 16.5 g dry wt bacteria/mole ATP for growth without an added hydrogen acceptor, 14.4 for growth with fumarate, and 14.2 for growth with nitrate.

Intervirology, 1977, 8(4), 204 - 17
Further biological properties of the human syncytial virus; Loh PC et al.; Some biological properties of the human syncytial virus have been examined . A 13-day plaque assay in whole human embryo fibroblasts (HEF) has been developed using a liquid (growth medium) overlay . The plaques were 0.7-2 mm in diameter and often showed a clear central zone with irregular edges . Pretreatment of HEF monolayers with the polycation DEAE-dextran for either 30 min or 1 h was found to enhance plaque formation by a factor of from 2- to 7-fold . The plaque assay procedure required cell cultures undergoing active cell division . Adsorption kinetics and growth cycle studies in HEF indicated a relatively long adsorption period (3 h) and a relatively prolonged latent period of 24 h . Even under optimal conditions, virus yields were low and did not exceed 1 PFU per infected cell . Like other animal syncytium-forming 'foamy' viruses, the human virus induced both intranuclear and cytoplasmic antigens detectable by immmunofluorescence and was also markedly labile to freezing and thawing.

J Supramol Struct, 1977, 6(3), 363 - 74
Defective transport of thymidine by cultured cells resistant to 5-bromodeoxyuridine; Lynch TP et al.; A line of HeLa cells resistant to 5-bromo-2'-deoxyuridine (BUdR) was established by continuous culture in growth medium containing BUdR; during the selection period, BUdR concentrations, initially 15 micrometer, were gradually increased to 100 micrometer . Cells of a clone (HeLa/B5) established from this line were also resistant to 5-fluoro-2'-deoxyuridine (FUdR), but not to the free base, 5-fluorouracil . Although extracts of HeLa/B5 cells exhibited levels of thymidine kinase activity comparable to those of parental cells, rates of uptake of BUdR, FUdR, and thymidine into intact cells were much reduced . The kinetics of uptake of uridine and adenosine, nucleosides which appear to be transported independently of thymidine in HeLa cells, were similar for HeLa/B5 and the parental line (HeLa/O) . Relative to thymidine uptake by HeLa/O cells, that by HeLa/B5 cells was distinctly less sensitive to nitrobenzylthioinosine (NBMPR), a specific inhibitor of nucleoside transport in various types of animal cells . Despite this difference in NBMPR sensitivity, both cell lines possessed the same number of high affinity NBMPR binding sites per mg cell protein . The altered kinetics of thymidine uptake and the NBMPR insensitivity of that function in HeLA/B5 cells suggest that resistance to BUdR is due to an altered thymidine transport mechanism.

Acta Microbiol Pol, 1977, 26(1), 59 - 64
Formylation and acetylation of 4-chloroaniline by a Streptomyces sp; Russel S et al.; 4-Chloroaniline was metabolized in a liquid growth medium by a Streptomyces sp . which was isolated from soil . After 60 gours of incubation the aniline had disappeared and several metabolites could be detected by thin layer chromatographic analysis . 4-Chloroformylaniline and 4-chloroacetanilide were identified as products . The formation of a formylanilide by the actinomycete indicates a new mechanism of microbial aniline transformation.

J Virol, 1977 Jan, 21(1), 328 - 37
Viral protein synthesis in Friend erythroleukemia cell lines; Racevskis J et al.; Viral protein synthesis was studied in two Friend virus-induced erythroleukemia cell lines (Ostertag cell lines FSD1-F4 and B8) by the technique of immuno-precipitation with monospecific antisera to the major envelope glycoprotein gp70 and major core protein p30 . One of the cell lines (F4) releases active Friend virus complex to the growth medium, where release of virus from the other cell line (B8) is barely or nondetectable . It was found that in the nonproducer cell line B8, a large-molecular-weight protein of about 65,000 containing p30 antigenic determinants is synthesized, yet no p30 is produced upon prolonged incubation and chase, suggesting that this might be the actual lesion that prevents mature virus production by these cells . In both cell lines, the predominant protein species that is immunoprecipitated with monospecific anti-gp70 serum is a protein of 55,000 to 60,000 daltons that is labeled with glucosamine to a much lesser extent that gp70 and appears to become heterogeneous with time . Large amounts of gp70 can be detected in the cell-free medium, but none of the unstable species of 55,00 to 60,000 molecular weight.

J Virol, 1977 Jan, 21(1), 366 - 74
Role of the pneumococcal autolysin (murein hydrolase) in the release of progeny bacteriophage and in the bacteriophage-induced lysis of the host cells; Ronda-Lain C et al.; The pneumococcal bacteriophage Dp-1 seems to require the activity of the N-acetylmuramic acid-L-alanine amidase of the host bacterium for the liberation of phage progeny into the medium . This conclusion is based on a series of observations indicating that the exit of progeny phage particles is prevented by conditions that specifically inhibit the activity of the pneumococcal autolysin . These inhibitory conditions are as follows: (i) growth of the bacteria on ethanolamine-containing medium; (ii) growth of the cells at pH values that inhibit penicillin-induced lysis of pneumococcal cultures and lysis in the stationary phase of growth; (iii) addition of trypsin or the autolysin-inhibitory pneumococcal Forssman antigen (lipoteichoric acid) to the growth medium before lysis; (iv) infection of an autolysin-defective pneumococcal mutant at a multiplicity of infection less than 10 (treatment of such infected mutant bacteria with wild-type autolysin from without can liberate the entrapped progeny phage particles); (v) release of phage particles and culture lysis can also be inhibited by the addition of chloramphenicol to infected cultures just before the time at which lysis would normally occur . Bacteria infected with Dp-1 under conditions nonpermissive for culture lysis and phage release secrete into the growth medium a substantial portion of their cellular Forssman antigen in the form of a macromolecular complex that has autolysin-inhibitory activity . We suggest that a phage product may trigger the bacterial autolysin by a mechanism similar to that operating during treatment of pneumococci with penicillin (Tomasz and Waks, 1975).

Biochemistry, 1976 Dec 14, 15(25), 5443 - 8
Effect of VP-16-213 on the intracellular degradation of DNA in HeLa cells; Loike JD et al.; The effect of VP-16-213 on cellular DNA was studied by following the sedimentation profiles of radioactive DNA in HeLa cells on alkaline sucrose gradients . In VP-16-213 treated cells, high-molecular-weight DNA is converted to a lower molecular-weight form in a dose-dependent, temperature-dependent reaction . The effect of VP-16-213 on cellular DNA is reversed after the drug has been removed from the growth medium for 150 min . These results suggest that VP-16-213 induces single-stranded breaks in DNA in HeLa cells and that HeLa cells can repair these breaks within 150 min . The nonglucoside derivative of VP-16-213, 4'-demethylepipodophyllotoxin, also induces the cleavage of cellular DNA but podophyllotoxin has no effect on DNA . A structure-activity relationship study, in which the effects of various VP-16-213 and podophyllotoxin congeners were tested for their ability to cleave cellular DNA,revealed that an hydroxyl group at the C-4' position is required for activity and that the configuration of the C-4 carbon influences the activity of a congener . These results may offer insights into the mechanism of action of VP-16-213 as an antitumor agent.

Dev Biol Stand, 1976 Dec 13-15, 37, 77 - 82
Problems related to the use of serum and trypsin in the growth of monkey kidney cells; Melnick JL et al.; A function of serum in the growth medium for primary monkey kidney cells has been shown to be inhibition of proteolytic enzymes . Serum inactivates the residual trypsin remaining from enzymatic digestion of the kidneys and the proteolytic enzymes subsequently synthesized by the cells . Freshly trypsinized cells could be grown to monolayers in the absence of serum provided that they were repeatedly washed to remove residual trypsin . In the absence of serum, cell growth ceased on the 4-5th day after initiation of the culture, at which time the culture fluids became active proteolytically . When the 5th day fluids were replaced with fresh serum-free medium, cell growth was accelerated and a monolayer was attained by the 7th day . If cells were grown in the absence of whole serum but in the presence of medium containing alpha globulins or fetuin which inhibit both trypsin and cell proteases, such cultures grew as well as cultures containing serum . The sterilization of trypsin for use in digestion of tissues and cell cultures poses a serious problem . After filtration through 0.22 micron filters, trypsin preparations may still contain adventitious viruses, mycoplasma and minute forms of pseudomonas and other bacteria or bacteria-produced toxins, which pass the membrane pores . A process of purifying and sterilizing trypsin without deleteriously affecting its proteolytic activity is described.

Acta Radiol Ther Phys Biol, 1976 Dec, 15(6), 551 - 9
Radiation sensitizing effect of diamide on human cells cultivated in vitro; Pettersen EO et al.; Human cells of line NHIK 3025 were irradiated suspended in growth medium (E2a) in absence and presence of diamide under aerobic and extremely hypoxic (less than 4 ppm O2) conditions . A sensitizing effect of diamide was found for doses exceeding 8 Gy (800 rad) on cells irradiated under extremely hypoxic conditions in presence of diamide of concentration 200 micrometer, whereas no significant effect was observed for 20 micrometer.

J Clin Microbiol, 1976 Dec, 4(6), 492 - 502
Cellular fatty acids and metabolic products of Pseudomonas species obtained from clinical specimens; Moss CW et al.; The cellular fatty acid composition of 112 reference strains and clinical isolates of Pseudomonas species was determined by gas-liquid chromatography (GLC) . The presence and relative amounts of cyclopropane, hydroxy, and branched-chain fatty acids were distinguishing features of these strains . Determination of short-chain fatty acids extracted from spent growth media provided an additional means for identifying some strains . Our results show that clinical isolates of pseudomonads can be divided into eight distinct GLC groups . The procedures were especially useful for distinguishing glucose-nonoxidizing pseudomonads, which are difficult to identify by conventional criteria . Since the GLC procedures are simple, rapid, and highly reproducible, they are useful in diagnostic laboratories that process large numbers of cultures . Coupled with selected conventional tests, the analysis of short-chain and cellular fatty acids can be very useful for rapid screening of clinical isolates of Pseudomonas species.

J Bacteriol, 1976 Dec, 128(3), 708 - 16
Chromosome segregation in Escherichia coli B/r at various growth rates; Pierucci O et al.; Chromosome segregation was analyzed in three substrains of Escherichia coli B/r growing at various rates . The cultures were pulse labeled with {14C}thymidine and bound to the bottom surface of a nitrocellulose membrane filter, and the radioactivity in newborn cells released from the surface during continuous elution with growth medium was measured . Since there was a fixed orientation in the release of newborn cells, the time course of the change in radioactivity per effluent cell could be used to investigate the orientation of chromosome segregation . If the radioactive deoxyribonucleic acid strands were partitioned at random between the progenies remaining attached to the membrane filter and those released into the effluent, the radioactivity per cell would decrease twofold after each generation of elution . The decrease in radioactivity was less than twofold at C + D min of elution and larger than twofold one generation later, indicating that chromosome segregation was nonrandom.

J Cell Physiol, 1976 Dec, 89(4), 677 - 81
Sodium: a regulator of glucose uptake in virus-transformed and nontransformed cells; Bader JP; Observations of cells transformed by the Bryan strain of Rous sarcoma virus (RSV-BH) suggested that the intracellular concentrations of sodium ion (Na+) may play a critical role in cellular metabolism . In an attempt to manipulate intracellular Na+, chick embryo cells were exposed to graded concentrations of Na+ in the cellular growth medium, and the effects on capacity for glucose uptake was examined . After incubation for six hours, the incorporation rate of 2-deoxyglucose (used as a substitute for glucose) was proportional to the external Na+ concentration over the range, 100 mM to 200 mM . Cells transformed by RSV-BH were less responsive than nontransformed cells to differences in Na+ at low concentrations . The changes were specifically dependent upon Na+, since K+, Li+, or choline + were ineffective as substitutes, and increasing the ionic strength above that of 120 mM Na+ was effective only when Na+ was the added cation.

Biochemistry, 1976 Nov 30, 15(24), 5228 - 33
Molecular control of membrane properties during temperature acclimation . Membrane fluidity regulation of fatty acid desaturase action?
Kasai R, Kitajima Y, Martin CE, Nozawa Y, Skriver L, Thompson GA Jr.
Further studies on the molecular mechanisms of temperature acclimation have been carried out using the ciliate Tetrahymena pyriformis . The most prominent change in lipid metabolism during acclimation to high temperature--depression of fatty acid desaturase activity--could be simulated by supplementing the growth medium of isothermally-grown cells with polyunsaturated fatty acids . Such cells resisted the membrane-fluidizing effect of the incorporated exogenous acids by increased use of de novo synthesized saturated acids in their phospholipids . The data support the conclusions arising from earlier experiments with temperature-shifted cells (Martin, C.E., Hiramitsu, K., Kitajima, Y., Nozawa, Y., Skriver, L., and Thompson, G.A., Jr . (1976), Biochemistry 15), showing that, when membrane fluidity increased to a superoptimal level, the activity of membrane-associated fatty acid desaturases was decreased . Since the reaction is controlled by membrane fluidity, rather than temperature per se, we postulate that it is the general mechnaism employed by cells adjusting to any fluidity-modifying factor, such as cations, drugs, etc.

Biochem J, 1976 Nov 15, 160(2), 305 - 14
One-carbon metabolism in Neurospora crassa wild-type and in mutants partially deficient in serine hydroxymethyltransferase; Cossins EA et al.; 1 . The concentrations of folate-dependent enzymes in Neurospora crassa Lindegren A wild type (FGSC no . 853), Ser-l mutant, strain H605a (FGSC no . 118), and for mutant, strain C-24 (FGSC no . 9), were compared during exponential growth on defined minimal media . Both mutants were partially lacking in serine hydroxymethyltransferase, but contained higher concentrations of 10-formyltetrahydrofolate synthetase than did the wild type . Mycelia of the mutants contained higher concentrations of these enzymes when growth media were supplemented with 1mM-glycine . In the wild-type, this glycine supplement also increased the specific activities of 5,10-methylenetetrahydrofolate dehydrogenase and 5,10-methylenetetrahydrofolate reductase . 5 . During growth, total folate and polyglutamyl folate concentrations were greatest in the wild-type . Methylfolates were not detected in mutant Ser-l, and were only present in the for mutant after growth in glycine-supplemented media . Exogenous glycine increased folate concentration threefold in the wild type, mainly owing to increases in unsubstituted polyglutamyl derivatives . 3 . Feeding experiments using 14C-labelled substrates showed that C1 units were generated from formate, glycine and serine in the wild type . Greater incorporation of 14C occurred when mycelia were cultured in glycine-supplemented media . Formate and serine were precursors of C1 units in the mutants, but the ability to cleave glycine was slight or lacking.

Atherosclerosis, 1976 Nov-Dec, 25(2-3), 205 - 12
Lipid metabolism in cultured aortic smooth muscle cells and comparison with other cell types . Part 2 . Reversibility of lipid accumulation caused by hyperlipemic serum; Pearson JD; The lipid compositions of cultured rabbit aortic smooth muscle cells and skin fibroblasts were determined for cells grown in media containing either normolipemic or hyperlipemic sera . Both cell types accumulated cholesteryl esters and triglycerides after treatment with hyperlipemic serum . Within 4 days of returning cells that had accumulated these neutral lipids to medium containing a low percentage of normolipemic serum, their concentrations in both cell types had returned to levels similar to those found in cells cultured in standard growth medium . Thus the accumulation of cholesteryl esters and triglycerides in smooth muscle cells, as in fibroblasts, may be completely reversed in vitro.

Lipids, 1976 Nov, 11(11), 791 - 7
Lipid accumulation cells derived from porcine aorta and grown under anaerobic conditions; Briggs RG et al.; Fibroblast-like cells, derived from porcine aorta, were cultured under aerobic and anaerobic conditions . Light and electron microscopic examinations, lipid composition measurements, and incorporation of radioactive precursors into lipids of these cells were performed . Anaerobically grown cells accumulated oil red O stainable droplets and within 6 hr the triacylglycerol content increased to 4 times the level determined in cells grown under aerobic conditions . This ratio remained constant throughout an additional 12 hr of growth . The fatty acid composition of the triacylglycerols which accumulated under anaerobic conditions differed from the composition of fatty acids in the triacylglycerols present in the growth medium . The cellular unesterified fatty acids of the anaerobically grown cells differed only slightly in composition from the fatty acids in the growth medium, while the unesterfied fatty acids of aerobically grown cells differed to a greater extent from those of the growth medium.

Diabetes, 1976 Nov, 25(11), 1011 - 7
Growth hormone stimulating the growth of arterial medial cells in vitro . Absence of effect of insulin; Ledet T; Earlier studies have shown a stimulatory effect of diabetic serum on the growth of rabbit aortic medial cell cultures . Growth media supplemented with normal serum with added insulin (50-2,000 muU./ml . serum) did not enhance the growth of the medial cell cultures . Control media containing serum from recent diabetics with low insulin concentration stimulated the growth (2p less than 0.01) . Supplementation of normal serum with human growth hormone (final concentration 1-5 ng./ml . medium) resulted in a significant enhancement of growth (2p less than 0.005) . The growth-promoting effect of growth hormone was not detectable with lower concentrations (0.5 ng . and 0.1 ng./ml . medium) . The growth effect of the low concentration of growth hormone could not be augmented by increasing the concentration of glucose in the incubation medium . Growth hormone in an amount of 1 ng./ml . medium increased both the number of 3H-thymidine-labeled cells as identified by autoradiography and the number of mitotic bodies (2p less than 0.005 and 2 p less than 0.025) . The present results demonstrate that the growth-stimulating factor(s) in diabetic human serum described earlier is not insulin but may well be growth hormone.

J Bacteriol, 1976 Nov, 128(2), 598 - 603
Regulation of hypoxanthine transport in Neurospora crassa; Sabina RL et al.; Hypoxanthine uptake and hypoxanthine phosphoribosyltransferase activity (EC 2.4.2.8) were determined in germinated conidia from the adenine auxotrophic strains ad-1 and ad-8 and the double mutant strain ad-1 ad-8 . The mutant strain ad-1 appears to lack aminoimidazolecarboximide ribonucleotide formyltransferase (EC 2.1.2.3) or inosine 5'monophosphate cyclohydrolase (EC 3.5.1.10) activities, or both, whereas the ad-8 strain lacks adenylosuccinate synthase activity (EC 6.3.4.4) . Normal (or wild-type) hypoxanthine transport capacity was found to the ad-1 conidia, whereas the ad-8 strains failed to take up any hypoxanthine . The double mutant strains showed intermediate transport capacities . Similar results were obtained for hypoxanthine phosphoribosyl-transferase activity assayed in germinated conidia . The ad-1 strain showed greatest activity, the ad-8 strain showed the least activity, and the double mutant strain showed intermediate activity levels . Ion-exchange chromatography of the growth media revealed that in the presence of NH+/4, the ad-8 strain excreted hypoxanthine or inosine, the ad-1 strain did not excrete any purines, and the ad-1 ad-8 double mutant strain excreted uric acid . In the absence of NH+/4, none of the strains excreted any detectable purine compounds.

Mycopathologia, 1976 Oct 22, 59(3), 171 - 4
Effects of adenine and cytokinins on growth and protein kinase activity of Verticillium albo-atrum; Atmar VT et al.; Growth of Verticillium albo-atrum in liquid Czapek-Dox broth was stimulated about four-fold by added 10 mM adenine, N6-benzyladenine, or kinetin . Less stimulation was evident at lower concentrations . With none of these included in the basal growth medium, detectable protein kinase activity in cell-free extracts was low and responded minimally to cAMP (adenosine 3',5'-cyclic monophosphate) in the reaction mixture . With each of these compounds as an additive to the growth medium, protein kinase activity was not only greater but also responded markedly (several fold) to cAMP . These results demonstrate a strong correlation between exogenously supplied adenine and related compounds, increased growth, increased protein kinase activity, and kinase response to cAMP in this organism.

Biochim Biophys Acta, 1976 Oct 21, 450(1), 21 - 32
The manipulation of the fatty acid composition of Dictyostelium discoideum and its effect on cell differentiation; Weeks G; The fatty acid composition of Dictyostelium discoideum has been modified by growing the axenic strain, Ax-2, in media conta-ning long chain polyenoic fatty acids . Large amounts of linoleic and linolenic acids are incorporated into the cellular lipids and further desaturated to two unusual fatty acids, 5,9,12-octadecatrienoic acid and 5,9,12,15-octadecatetraenoic acid, respectively . Arachidonic acid is also extensively incorporated but not further de;aturated . D . discoideum normally contains none of the above polyenoic fatty acids, and the amount incorporated depends upon the concentration of the fatty acid in the growth media . The cells containing large quantities of polyenoic fatty acid grow normally b,t exhibit impaired differentiation when removed from the growth medium . The incorporation of smaller quantities of the fatty acid has no adverse effect on differentiation . Cells grown in the presence of saturated or monoenoic fatty acids exhibit, at the most, only slight changes in the fatty acid composition of the cellular lipid and both grow and differentiate normally.

Eur J Biochem, 1976 Oct 1, 69(1), 257 - 63
The uptake and metabolism of uridine by the slime mould Physarum polycephalum; Birch B et al.; 1 . Uridine is taken up by microplasmodia of Physarum polycephalum via a saturatable transport system with an apparent Km of 29 muM . An intracellular concentration significantly higher than that in the growth medium is attained, suggesting that the uptake is an active process . Both deoxyribonucleosides and ribonucleosides are competitive inhibitors of the uptake of uridine . 2 . In contrast, the rate of entry of uridine into surface plasmodia is a linear function of the concentration of the nucleoside in the growth medium, and the uptake is not inhibited by other nucleosides . 3 . As well as serving as a source of pyrimidine nucleotides for the synthesis of nucleic acids, uridine is also catabolised by P . polycephalum . Uracil accumulates in the growth medium and there is also significant conversion of C-2 of the pyrimidine ring to CO2 . The proportion of uridine subject to catabolism in surface plasmodia is less than that observed for microplasmodia.

Steroids, 1976 Oct, 28(4), 535 - 48
15-Azasteroid blockage of cell permeability and mitochondrial respiration; Chesnut RW et al.; The 15-azasteroid, 1,10,11,11a-tetrahydro-11a-methyl-2H naphth (1,2-g)indol-7-o1, inhibits the growth of the cell culture lines KB and L-M as well as several strains of bacteria . The inhibition of growth is reversed following removal of the steroid from the growth medium . Using in vitro grown L-M cells, the compound inhibited the transport of amino acids and uracil . The action was non-detergent like and at least 100 times more effective in terminating metabolite transport than sodium azide . The azasteroid inhibited the oxidation of glutamate in isolated rat liver mitochondria . The oxidation of succinate was not effected by the azasteroid alone but in the presence of glutamate, the azasteroid uncoupled the oxidation of succinate from the ADP-ATP control . It is suggested that the azasteroid may be acting directly on the electron transport system and/or acting indirectly through membrane perturbations which disrupts the electron transport process.

J Bacteriol, 1976 Oct, 128(1), 170 - 3
Biosynthesis of saturated and unsaturated fatty acids by a T-strain mycoplasma (Ureaplasma); Romano N et al.; A human T mycoplasma (Ureaplasma urealyticum) incorporated radioactivity into its lipids from {1-14C}acetate in the growth medium . Methanolysis of the lipids showed the label to be confined almost entirely to the methyl esters of the fatty acids . About 80% of the label was associated with the methyl esters of the saturated fatty acids, and the rest was found in the unsaturated methyl ester fraction . Gas-liquid chromatography of the saturated methyl esters showed the label to be present in the peaks of palmitate, myristate, and stearate, whereas in the unsaturated methyl ester fraction most of the radioactivity emerged in the peak of palmitoleate . The addition of either oleic or palmitic acid to the growth medium markedly decreased the organisms' incorporation of radioactivity from acetate . It is concluded that the T mycoplasma strain is capable of de novo synthesis of both saturated and unsaturated fatty acids, in this respect differing from all of the Mycoplasma and Acholeplasma strains investigated to date.

Cell, 1976 Oct, 9(2), 205 - 11
Characterization of a cell culture model for the study of adenosine deaminase- and purine nucleoside phosphorylase-deficient immunologic disease; Ullman B et al.; The absence of erythrocytic adenosine deaminase (ADA) or purine nucleoside phosphorylase (PNP) has been associated with severe immunodeficiency disease in children . We have developed a cell culture model to study the possible relationships between purine salvage enzymes and immunologic function using an established T cell lymphosarcoma (S49) and a potent inhibitor of ADA, erythro-9(2-hydroxy-3-nonyl) adenine (EHNA) . Wild-type S49 cells are killed by dexamethasone or dbc AMP, and adenosine (5 muM) in the presence of an ADA inhibitor (6 muM EHNA) also prevents the growth of and kills these S49 cells . It has been proposed that adenosine is toxic to lymphoid cells by virtue of its ability to increase the intracellular concentrations of cyclic AMP . We examined the sensitivity of three mutants of S49 cells, with distinctive defects in some component of cyclic AMP metabolism or action, to killing by adenosine and EHNA . All three mutants are resistant to killing by isoproterenol or cholera toxin and two are resistant to dbc AMP itself, but all are sensitive to killing by adenosine and EHNA . Similarly, two dexamethasone-resistant S49 mutants are as sensitive to adenosine and EHNA as are the wildtype cells . We have also simulated the purine nucleoside phosphorylase deficiency in S49 cells by adding inosine and adenosine to the growth medium . In the presence of EHNA or inosine, the toxic effects of adenosine can be partially reversed by addition of (10-20 muM) uridine, an observation suggesting that adenosine is toxic as the result of its inducing pyrimidine starvation.

Biochim Biophys Acta, 1976 Sep 24, 444(2), 539 - 53
Cyclic AMP and growth of Ehrlich ascites tumor cells . Lack of cyclic AMP elevation in nutritionally deprived cells and mechanism of retardation of growth by dibutryl cyclic AMP; Kaminskas E et al.; Cyclic AMP levels in Ehrlich ascites tumor cells changed little after deprivation of cells of essential nutrients, serum, glucose and amino acids, deprival of each of which leads to marked inhibition of growth and protein synthesis . Cyclic AMP levels also changed little after the addition of these nutrients to deprived cells . Thus cyclic AMP is not likely to be the intracellular mediator for growth regulation by these three nutrients . Elevation of cyclic AMP levels for short periods by exposure of cells to choleratoxin or theophylline produced only slight changes in parameters of protein synthesis (polyribosome pattern and rate of {3H}leucine incorporation) . An exposure for 1 day to dibutyryl cyclic AMP did not inhibit cell growth . However, prolonged exposure to dibutyryl cyclic AMP inhibited the multiplication of Ehrlich ascites cells both in suspension and in stationary cultures . No morphological effects were evident in the former; in the latter, cells attached firmly to the substratum and formed elongated cytoplasmic processes . Inhibition of cell multiplication by dibutyryl cyclic AMP was related to cell density and to serum concentration . Cells in dibutyryl cyclic AMP-containing media plated at low cell densities multiplied as rapidly as control cells . The final densities cells reached were determined by the serum concentration; in dibutyryl cyclic AMP-containing media these densities were about one-half those of respective control cells . Limitation of cell multiplication by dibutyryl cyclic AMP was reversed by the addition of serum, by resuspending cells at lower densities, or by resuspending cells in media without dibutyryl cyclic AMP . These findings suggested that dibutyryl cyclic AMP may affect the utilization of serum factors by cells . Dibutyryl cyclic AMP did not inactivate serum factors and did not change the rate at which cells depleted the growth medium of serum factors . Dibutyryl cyclic AMP may limit cell multiplication by increasing the cellular requirement for serum factors.

Mol Gen Genet, 1976 Sep 23, 147(3), 251 - 62
Influence of cultural conditions and mutations on the composition of the outer membrane proteins of Escherichia coli; Lugtenberg B et al.; Various Escherichia coli strains differ in the composition of their major outer membrane proteins . However, all E . coli K12 strains tested possess the same major outer membrane proteins a, b, c and d, although quantitative differences were detected . The influence of growth conditions on the composition of the major outer membrane proteins of E . coli was analyzed . It was found that neither the growth phase at which the cells are harvested, nor the fatty acid composition of the phospholipids has a considerable influence on the composition of these proteins . However, the composition of the growth medium, and, to a less extent, the growth temperature, have a pronounced influence . Certain mutants, changed in the composition of their lipopolysaccharide, are deficient in protein b . Also mutants deficient in protein c and d respectively, are described . Proteins b and c of E . coli K12 were found to be associated with peptidoglycan . Protein bands, corresponding with flagellin and pilin respectively, were identified.

Biochem J, 1976 Sep 15, 158(3), 567 - 73
The synthesis of glycosaminoglycans by cultures of rabbit corneal endothelial and stromal cells; Yue BY et al.; Confluent monolayer cultures of rabbit corneal endothelial and stromal cells were incubated independently with {35S}sulphate and {3H}glucosamine for 3 days . AFter incubation, labelled glycosaminoglycans were isolated from the growth medium and from a cellular fraction . These glycosaminoglycans were further characterized by DEAE-cellulose column chromatography and by sequential treatment with various glycosamino-glycan-degrading enzymes . Both endothelial and stromal cultures synthesized hyaluronic acid as the principal product . The cell fraction from the stromal cultures, however, had significantly less hyaluronic acid than that from the endothelial cultures . In addition, both types of cells synthesized a variety of sulphated glycosaminoglycans . The relative amounts of each sulphated glycosaminoglycan in the two cell lines were similar, with chondroitin 4-sulphate, chondroitin 6-sulphate and dermatan sulphate as the major components . Heparan sulphate was present in smaller amounts . Keratan sulphate was also identified, but only in very small amounts (1-3%) . The presence of dermatan sulphate and the high content of hyaluronic acid are similar to the pattern of glycosaminoglycans seen in regenerating or developing tissues, including cornea.

Cancer Treat Rep, 1976 Sep, 60(9), 1363 - 7
Amino acid-conferred resistance to melphalan . I . Structure-activity relationship in cultured murine L1210 leukemia cells; Vistica DT et al.; Melphalan cytotoxicity to murine L1210 leukemia cells in culture was reduced in growth medium containing amino acids . Investigation of the effect of single amino acids revealed that the L-isomers of glutamine and leucine, but not the D-isomers, were the most active in decreasing cytotoxicity . Protection was concentration dependent, with maximum protection occurring at approximately 0.25 mM, a physiologic concentration . The LD90 for melphalan in the presence of 0.1 mM L-glutamine or L-leucine was increased by 7.3- and 10.8-fold respectively, under conditions where the cells had been pre-incubated with the amino acids . These results are interpreted to suggest that melphalan transport by the L1210 leukemia cell is mediated by a system also responsible for the transport of glutamine and leucine and that interaction with such a system may play a significant role in the chemotherapeutic activity of this alkylating agent.

Arch Microbiol, 1976 Sep 1, 109(3), 227 - 35
Regulation of amino acid transport in growing cells of Streptomyces hydrogenans . I . Modulation of transport capacity and amino acid pool composition during the growth cycle; Langheinrich W et al.; (1) The active uptake of different amino acids by growing cells of Streptomyces hydrogenans was shown to be correlated with the physiological age of the cells . During the lag phase of growth the transport capacity increased and attained its highest level when the growth rate was maximum . During further growth the transport capacity declined progressively . The lowest transport activity was observed when the culture shifted into the stationary growth phase . (2) Such modulation of transport capacity was independent on the presence or absence of amino acids in the growth medium of the cells . (3) The size and the composition of the pool of free intracellular amino acids was also undergoing substantial variations during the growth cycle of the culture . In the lag phase, the levels of all amino acids decreased markedly and attained their lowest values at the end of this phase . During further growth the pool size was slowly replenished . (4) Removal of the pool resulted in a considerable gain of transport capacity . Therefore, it was concluded that active amino acid transport in growing Streptomyces hydrogenans is under feedback control by intracellular amino acids . (5) Quantitatively, the modulation of the pool size could not fully account for the variation of the transport capacity . Since a pool-independent stimulation of transport was found to be correlated with the increase of the growth rate of the cells, the possibility is discussed that the stimulation of transport is either due to increased levels of distinct RNA species, which might provide positive feedback signals for transport, or by increased rates of de novo synthesis of transport limiting proteins.

J Cell Physiol, 1976 Sep, 89(1), 111 - 22
Density-dependent regulation of proliferation rate in cultured, androgen-responsive, tumour cells; ROBINSON JH et al.; Short-term cultures of androgen-responsive Shionogi 115 (S115) cells exhibited density-dependent regulation of proliferation rate in the presence or absence of testosterone . The average surface area per cell exposed to the growth medium was inversely proportional to population density . By contrast, long-term cultures (serially passaged in testosterone-containing medium for several months) did not exhibit density-dependent regulation of proliferation rate when grown in testosterone-containing medium . In this medium, cells became elongated and no longer exhibited any obvious decrease in exposed surface area with increasing density . Nevertheless, when subcultured into testosterone-free medium, these cells reverted to an epithelial morphology and exhibited density-dependent regulation of proliferation rate . These relationships suggested that the proliferation rate of cells decreased with density in proportion to the decrease in exposed surface area...

Can J Microbiol, 1976 Sep, 22(9), 1282 - 92
The isolation and characterization of gliding motility mutants of Myxococcus xanthus; MacRae TH et al.; Nonmotile and motility-altered mutants of Myxococcus xanthus have been obtained by the use of chemical mutagens, ultraviolet irradiation, and a procedure for selective spontaneous mutants . As judged by their behaviour on a variety of growth media, in both plate and slide culture, the mutants were divided into four groups . One group contains mutants which are truly nonmotile . Myxococcus xanthus NM, previously described as a nonmotile mutant, may be similar to type 3 mutants (described in text).

J Bacteriol, 1976 Sep, 127(3), 1370 - 5
Iron transport of Escherichia coli K-12: involvement of the colicin B receptor and of a citrate-inducible protein; Hancock RE et al.; It was shown that feuB mutants (defective in ferric enterochelin uptake) were unable to adsorb colicin B . In addition, they were missing one of the three outer-membrane proteins which are over produced in strains grown in iron-deficient, extracted medium . Thus this protein (the feuB protein) is probably the receptor for colicin B and functions in enterochelin-mediated iron transport . The feuB gene was located by P1 transduction at approximately 72.5 min on the Escherichia coli K-12 genetic map and thus maps separately from the other genes concerned with the enterochelin system . The outer membranes of various strains grown in the presence of 1 mM citrate contained a high level of a protein which was present in very small amounts when citrate was absent from the growth medium . This protein was most easily observed in feuB mutants grown in the presence of citrate, since on polyacrylamide gels it ran in a similar position to the feuB protein, which is missing in these mutants . The relationship of this citrate-inducible protein to the inducible citrate-dependent iron uptake system is discussed.

J Bacteriol, 1976 Sep, 127(3), 1307 - 14
Role of deoxyribonucleic acid polymerase III in the repair of single-strand breaks produced in Escherichia coli deoxyribonucleic acid by gamma radiation; Hamelin C et al.; Cell survival, deoxyribonucleic acid (DNA) degradation, and the repair of DNA single-strand breaks were measured for Escherichia coli K-12 pol+, polA1, polC1026(ts), and polA1 polC1026(ts) cells after 137Cs gamma irradiation . The results indicate that DNA polymerase III is required for growth medium-dependent (type III) repair in polA+ or polA cells . In pol+ or polC cells, DNA polymerase I performs type II repair efficiently . The relative deficiencies of each of these strains in DNA repair generally correlate with their relative sensitivities to cell killing and with the extent of DNA degradation observed.

Cancer Res, 1976 Sep, 36(9 pt.1), 3207 - 11
Inhibition of membrane transport of 5-fluoro{6-3H}deoxyuridine into L5178Y mouse leukemia cells; Wigler PW et al.; The influx of 1.0 muM 5-fluoro{6-3H}deoxyuridine (5F{6-3H}dUrd) into L5178Y mouse leukemia cells followed a linear function with time from 2 to 10 min . Ammonium 5-bromodeoxyuridine 5'-methylphosphonate (BrdUrd-OPO2Me) inhibited the membrane transport of 5F{6-3H}dUrd into L5178Y cells . Influx of 5F{6-3H}dUrd into inhibited cells was observed from zero to 3 min; after 3 min the net rate of 5F{6-3H}dUrd uptake into the cells treated with 18 muM BrdUrd-OPO2Me was almost zero . The cellular uptake of 2'-deoxy{6-3H}uridine or 5-bromo{6-3H}deoxyuridine was inhibited by BrdUrd-OPO2Me . The L5178Y cells were grown for 96 hr in a medium that contained tritium-labeled BruDur-OPO2Me . An analysis of the labeled products in the growth medium showed that the ester linkage is not cleaved to separate the {3H}methylphosphonate group and the nucleoside moiety of BrdUrd-OPO2{3H}Me . The activity of thymidine kinase in a cell-free preparation from L5178Y cells was demonstrated . Although 37 muM 5-bromo-2'deoxyuridine produced an inhibition of approximately 45% in kinase activity, BrdUrd-OPO2Me had no effect on enzyme activity . The results indicate that BrdUrd-OPO2Me is an inhibitor of the cell membrane transport of the 5-fluoro and 5-bromo derivatives of 2'-deoxy{6-3H}uridine.

Can J Microbiol, 1976 Sep, 22(9), 1300 - 6
Production of volatiles from decomposing plant tissues and effect of these volatiles on Rhizoctonia solani in culture; Lewis JA; Volatiles, of which NH3 is a major component, were evolved from decomposing immature corn tissue (c:n9) and affected R . solani in culture two ways: they supplied additional nitrogen to the growth medium so that fungal mycelial growth increased; and they raised substrate pH from 5.5 to 8.2 which induced melanization of mycelium . Volatiles increased fungus growth and pigmentation within 2 weeks of amendment addition to soil . Increases were concomitant with NH3 production from corn tissue . More NH3 evolved from decomposing corn tissues of C:N9 and 17 than from those of C-N 33 and 81 . More growth and pigmentation occurred in flasks through which volatiles from decomposing corn (C:N9) were passed than in flasks through which volatiles from nonamended soil or decomposing corn (C:N81) were passed . Carbon dioxide from decomposing tissues did not affect growth or pigmentation . Twice as much NH3 evolved from corn tissue (C:N9) which decomposed in saturated soil than from tissue which decomposed in soil at 50% of its water-holding capacity . Pigment production doubled under saturated conditions.

Can J Microbiol, 1976 Sep, 22(9), 1233 - 44
Dependence of the superficial layers of Spirillum putridiconchylium on Ca2+ or Sr2+; Beveridge TJ et al.; Chelating agents disrupted the superficial layers on Spirillum putridiconchylium and adsorption of cationized ferritin indicated that both upper and lower surfaces of superficial layer fragments, as well as the outer membrane surface, possessed areas which were negatively charged . Growth of the bacterium in 1% casamino acids (vitamin free) resulted in cells which were devoid of the superficial layers, and negative staining of these cells revealed in amorphous precipitate together with a vesicular outer membrane component extruding from their surfaces into the medium . Addition of either 1 mM Ca2+ or 1 mM Sr2+ to the growth medium produced the typical regularly structured cell surface, whereas addition of equal concentrations of Li+, Na+, K+, Mg2+, Ba2+, Mn2+, Fe3+, or three polyamines produced the structureless surface.

Biochem J, 1976 Aug 15, 158(2), 235 - 41
Polyamine and ornithine metabolism during the germination of conidia of Aspergillus nidulans; Stevens L et al.; 1 . The activities of ornithine decarboxylase, S-adenosylmethionine decarboxylase and ornithine-2-oxoglutarate aminotransferase were studied during the first 24 h of conidial germination in Aspergillus nidulans . 2 . Increases (over 100-fold) in the activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase occurred during the emergence of the germ-tube and before the doubling of DNA and this was followed by a sharp fall in the activities of both enzymes by 16h . 3 . The increase in ornithine decarboxylase could be largely suppressed if 0.6 mM-putrescine was added to the growth medium . 4 . Low concentrations of cycloheximide, which delayed germination by 2h, caused a corresponding delay in the changes in ornithine decarboxylase activity . 5 . Ornithine-2-oxoglutarate aminotransferase activity increased steadily during the first 24h of germination . 6 . Ornithine or arginine in the growth medium induced higher activity of ornithine-2-oxoglutarate aminotransferase, but did not affect ornithine decarboxylase activity . 7 . The significance of these enzyme changes during germination is discussed.

J Gen Virol, 1976 Aug, 32(2), 261 - 73
On the regulation of protein synthesis in vaccinia virus infected cells; Oppermann H et al.; All eukaryotic mRNA species show a characteristic individual translational efficiency under conditions of restricted polypeptide chain initiation caused by an increase in the osmolarity of the growth medium . In vaccinia virus infected L cells or HeLa cells virus mRNAs can be grouped into classes on the basis of their relative labelling under standard and hypertonic conditions . Under the latter conditions, most of the "early" mRNAs possess very high translational efficiencies, most of the "intermediate" mRNAs show an intermediate efficiency and the most prominent "late" mRNAs show a translational efficiency which is lower than that of other virus mRNAs but still higher than the average cellular mRNA . Late in the infection cycle virus mRNAs with a relative low translational efficiency are preferentially translated under standard growth conditions whereas "early" virus mRNAs which are still present and which show a higher translational resistance to hypertonic conditions are not translated . These results indicate a unique translational control operating late in the growth cycle of vaccinia virus.

Arch Microbiol, 1976 Aug, 109(1-2), 37 - 43
Cell wall formation in zoospores of Allomyces arbuscula . II . Development of surface structure of encysted haploid zoospores, rhizoids, and hyphae; Kroh M et al.; Development of haploid meiospores of Allomyces arbuscula into germling cells with rhizoids and hyphae was followed during incubation in complete growth medium . The surface structure of encysted meiospores, rhizoids and hyphae before and after extraction of amorphous materials with ethanolic KOH was studied by means of carbon-platinum replicas . After 2--3 min incubation in complete medium 10% of the meiospores were surrounded by a cell wall containing microfibrils embedded in a matrix . Structure of cell walls of encysted meiospores, rhizoids, and hyphae differ from one another by the location of amorphous materials and by the arrangement of chitin microfibrils.

Mutat Res, 1976 Aug, 36(2), 171 - 6
UV-induced lethal sectoring and pure mutant clones in yeast; Hannan MA et al.; The induction of lethal sectoring and pure mutant clones by ultraviolet light has been studied in a homogeneous G1 population of Saccharomyces cerevisiae grown in a normal growth medium . At the lowest UV dose of 250 ergs, which corresponds to a shoulder in the survival curve, all mutants appeared as pure clones . At higher doses the frequency of mosaic mutants progressively increased . These results indicate a relationship between the highest frequency of complete mutants and the maximum repair activity . In addition, the frequency of lethal sectoring at all doses tested was too low to account for the origin of pure mutant clones.

Jpn J Microbiol, 1976 Aug, 20(4), 331 - 8
Enhanced growth and plaquing of rabies virus in static chick embryo cell culture; Sekine N et al.; The 7-day egg passage line of HEP Flury strain of rabies virus was inoculated to primary chick embyro (CE) cells prepared in different ways to compared efficiencies of viral growth and plaquing . Special care to minimize cellular damage due to trypsin at the step of monodispersion and sowing a comparatively large number of cells for monolayer preparation were required for rabies plaquing, whereas such cares were not necessary for plaquing of vesicular stomatitis virus . Plaque number and size were increased by incorporation of a high concentration of thymidine into cell growth medium . Various other means to produce a static state of CE cells were tested, and a maximal plaquing efficiency was obtained when dishes receiving a massive number of dispersed cells in MEM plus 1% calf serum were incubated at 37 C for 1 day without any buffering for monolayer preparation and postinfection incubation was done at 32 C in a CO2-incubator . Bottle cultures of CE cells prepared in a similar manner, when infected with HEP Flury virus, yielded a markedly higher titer of virus that CE cells prepared by our previous standard method.

J Cell Physiol, 1976 Jul, 88(3), 277 - 86
Effect of serum on the growth of Balb oT3 A31 mouse fibroblasts and an SV40-transformed derivative; Bartholomew JC et al.; The effect of serum on the growth properties of non-transformed Balb 3T3 A31 and SV40-transformed Balb 3T3 A31 was studied . The concentration of serum in the growth medium of non-transformed cells had little effect on the initial population doubling time, but did regulate the cell density at which the population became quiescent in G1 . The doubling time of transformed cells, however, was increased significantly as the concentration of serum was decreased below 4% . This effect on the growth of transformed cells was seen at serum concentrations so low that non-transformed cells did not complete one population doubling . Flow microfluorometric analysis of these populations indicated that the primary effect of different serum concentrations on the non-transformed cells was to modulate the average residence time in G1, whereas, all the cell cycle phases of the transformed cells were affected by serum . At saturation densities, the non-transformed cells became quiescent in G1, but the transformed cells still traversed the cell cycle and their saturation density appeared to be a balance between cell production and cell death occurring primarily in the G1 phase of the cell cycle.

Hoppe Seylers Z Physiol Chem, 1976 Jul, 357(7), 925 - 35
Biosynthetic labelling of membrane lipids of eukaryotic cells in tissue culture by a novel type of fluorescent fatty acids; Stoffel W et al.; W-Anthryl labelled fatty acids with hydrocarbon chains of different lengths (C8, C11, C15) and different degrees of unsaturation have been incorporated into the membrane lipids of three different cell lines in tissue culture by addition of these 3H-labelled precursor fatty acids to the growth medium . The cell lines were baby hamster kidney cells (BHK 21), Chang liver cells and the RN6 cell line derived from a chemically induced Schwannoma tumor cell clone . Cell growth was normal . The quantitative analysis on the basis of radioactivity determinations demonstrated that the fluorescent-labelled fatty acids were introduced into the neutral lipid fraction (triglycerides, diglycerides, and cholesterol esters, all present in small amounts), but mainly into the phospholipid classes phosphatidylcholine, -ethanolamine and -serine, and to a lesser extent, as N-acyl component of sphingolipids (sphingomyelins, ceramides, mono- and diglycosylceramides) . Cell fractionation studies indicated that the membranes of all subcellular particles were labelled with the fluorescent probes in their lipid moieties . These w-anthryl fatty acids are the first type of fluorescent lipid precursors which can be incorporated biosynthetically in vivo into membrane lipids of eukaryotic cells . The effective incorporation of the bulky fluorescent anthryl group in the terminal position of fatty acids of different chain lengths into the complex membrane lipids of the cell gives proff of 1) their uninhibited membrane transport, 2) their activation by the acyl-CoA synthetase and 3) their substrate properties for the O- acyl and N-acyl transferases in phospho- and sphingolipid biosynthesis.

Hoppe Seylers Z Physiol Chem, 1976 Jul, 357(7), 917 - 24
Biosynthetic incorporation of fatty acids with photosensitive groups into membrane lipids of cells in tissue culture; Stoffel W et al.; The physical methods (13C-NMR-spectroscopy and fluorescence spectroscopy) hitherto used for the elucidation of lipid-lipid and lipid-protein interactions in artificial and simple natural membranes were extended to the application of fatty acids, phospholipids and sphingolipids with photochemical labels (azide group) in defined positions, which on photolysis generate nitrenes . These highly reactive groups react with neighbouring molecules, either lipids or polypeptide chains, with insertion or addition . Highly radioactive 12-azido{9,10-3H2}stearic acid, 12-azido{12-3H}oleic acid and 18-azido-{9,10,12,13-3H4}linoleic acid were added to the growth medium of eukaryotic cell lines in tissue culture (BHK 21 cells and Chang liver cells) . They were incorporated into neutral, phosphoand sphingolipids in amounts comparable with the unsubstituted parent fatty acids . The distribution of the azido fatty acids in the phospholipids has been determined by enzymatic hydrolysis (phospholipase A2) on the basis of the distribution of their radioactivity . Radio gas chromatography and combined gas chromatography and mass spectroscopy revealed that the azide group of the radioactive fatty acids remained unaltered.

Mikrobiologiia, 1976 JUL-AUG, 45(4), 620 - 4
{Biogenesis of cellulolytic enzymes by Trichoderma ligorum on media with "inductor"}; Lobanok AG et al.; Identical distribution of C2- and Cx-cellulase activities of enzyme complexes produced by Trichoderma lignorum on a medium with lactose, a soluble "inductor", and on a medium with cellulose was found by means of disc elestrophoresis in polyacrylamide gel . The maximum rate of synthesis of cellulases on the medium with lactose was registered during the highest deceleration, and even complete cessation, of the fungal growth . During this phase, only one electrophoretically homogeneous cellulase component with Rf of 0.44 possessing all types of the cellulase activity is present in the cultural broth . In the course of growth of the fungus on cellulose after 48 hours, also only one electrophoretically homogeneous component with Rf of 0.44 was found in the cultural broth when the rate of the substrate degradation was highest . The appearance of minor protein components with the activity of cellulase at later stages of cultivation after cessation of the fungal growth is supposed to be caused by modification of the main cellulase component with Rf of 0.44 by the growth medium.

Mikrobiologiia, 1976 JUL-AUG, 45(4), 685 - 9
{Comparative physiology of the replication of RNA-containing bacteriophages MS2 and Q beta}; Bauman VR et al.; The yield of the phage QB is always less than the yield of the phage MS2, the conditions of cultivation being similar . This is due to the fact that the yield of the phage QB from an infection centre is lower by a factor of 5--10 than the yield of the phage MS2 . The yield of the phages may be increased by optimizing conditions of cultivation . The RNA-containg phages MS2 and QB were cultivated in the peptone-yeast growth medium in fermenters with the working volume of 30 and 50 litres . The yields were 2--5-10(13) particles/ml and 1--4-10(12) particles/ml for the phages MS2 and QB, respectively . The specific infectiveness of purified phage preparations was 2--4-10(12) particles/OD260 (MS2) and 2--4-10(11) particles/OD260 (QB).

In Vitro, 1976 Jul, 12(7), 517 - 20
Changes in soluble proteins in callus cells of hypersensitive tobacco inoculated with tobacco mosaic virus; Beachy RN et al.; Protein changes occurred in callus cells of hypersensitive tobacco (Nicotiana tabacum var . Xanthi-nc) 72 hr after inoculation with tobacco mosaic virus and incubation on a minimal growth medium . Two protein bands, serologically related to viral coat protein, were obtained from extracts of infected cells following electrophoresis on 7% and 10% polyacrylamide gels . An additional, slower migrating protein, perhaps due to virus-induced stimulation of a host protein, also was detected . Although local lesions appeared on callus after 40 hr of incubation, four proteins previously reported in lesion-bearing hypersensitive tobacco leaves were not found . The possible significance of this and the usefulness of a callus-TMV system as a tool to study virus-induced protein changes are discussed.

J Physiol, 1976 Jul, 259(1), 83 - 101
Evidence for genetic control of glycine uptake in cultured cells, regulated by the amino acid concentration of the growth medium; Hume SP et al.; 1 . Cultured cells were grown in various concentrations of amino acids for periods up to 3 days and the characteristics of the glycine transport system measured under fixed experimental conditions . During this time, the effect of enucleation, using cytochalasin B, and the effects of protein synthesis inhibitors (cycloheximide and actinomycin D) were investigated . 2 . Glycine influx is regulated by the prior growth concentration of similarly transported amino acids . 3 . The modification in transport involves primarily a change in Vmax (but also a change in Km in HeLa cells) and is effected within 2-10 hr after media change . Increased transport activity is calculated to be sufficient to compensate for the reduction in extracellular amino acid concentration, so that nearly normal influx values from media are maintained . Regulation over the range of concentrations studied is shown to be very accurate . 4 . The nucleus is essential for the regulatory mechanism to function . It seems probable that mRNA synthesis is required for acquisition of increased transport activity and mRNA translation required for maintenance of normal activity . 5 . The controlling factor in the regulatory mechanism appears unlikely to be intracellular pool size . Other possible signals are discussed.

Arch Pathol Lab Med, 1976 Jul, 100(7), 360 - 6
Scanning electron microscopy of Mycoplasma-infected tracheal rings; Woodruff KH; Sequential changes visualized by scanning electron microscopy are described in hamster tracheal ring cultures exposed to 10(5) colony-forming units/ml of Clyde strain M-129 Mycoplasma pneumoniae . Loss of cilia, elevation of cell borders, and clumping of microvilli were induced within six hours after incubation of the rings in media containing mycoplasmas and in sterile used media . This finding lends support to the theory that the toxicity of Mycoplasma infection is partially attributable to alterations in the growth medium or elaboration of a toxic substance by the organisms . Mycoplasmas were observed attaching to tracheal ring surfaces eight hours after infection . With increasing periods of incubation, cell death and alterations occurred in tracheal surface structure that might be confused with the organisms.

J Bacteriol, 1976 Jul, 127(1), 595 - 609
Control of the synthesis of alkaline phosphatase and the phosphate-binding protein in Escherichia coli; Willsky GR et al.; Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunological techniques, we have compared the synthesis of the phoA protein (alkaline phosphatase) and the phoS protein (phosphate-binding protein) in response to the level of phosphate in the medium in different genetic backgrounds containing the known alkaline phosphatase control mutations . Both proteins are produced in excess phosphate media in a phoR1a- strain, whereas neither protein is produced in a phoB- strain even under derepression conditions . In four different phoR1c- strains, however, the phoA product cannot be detected in extracts of cells obtained from any growth condition, whereas the phoS product is produced in both excess and limiting phosphate media . It is not yet known if phoR1c- mutants are a special class of mutations within the phoB gene or whether they occur in a separate cistron involved in alkaline phosphatase regulation . From these results we conclude that the expression of the phoA gene is not always co-regulated with expression of the phoS gene product . We have determined that the phoS protein is a component of periplasmic protein band P4 described by Morris et al . (1974) . The phoS product lacks sulfur-containing amino acids and is extractable by treatment with polymyxin sulfate . The other component of band P4 contains methionine and/or cysteine and is not extracted by polymyxin sulfate treatment . Like the phoS and phoA proteins, its synthesis is sensitive to the concentration of phosphate in the growth medium . In addition, the existence of a new class of periplasmic proteins synthesized at maximum rate in high phosphate media is demonstrated.

Z Naturforsch {C}, 1976 Jul-Aug, 31(7-8), 486 - 7
Nucleoside triphosphate levels in Streptomyces hydrogenans during growth and induction of 20beta-hydroxysteroid dehydrogenase; Betz J et al.; Levels of the purine nucleoside triphosphates are decreasing towards the end of log phase growth of Streptomyces hydrogenans . Induction of 20beta-hydroxysteroid dehydrogenase by addition of 11beta,21-dihydroxy-4,17(20)-pregnadien-3-one to the growth medium leads to a pronounced drop in purine nucleoside triphosphate levels with is irreversible in contrast to the initial loss and later accumulation of RNA.

J Bacteriol, 1976 Jul, 127(1), 249 - 57
Relationship between the transport of iron and the amount of specific colicin Ia membrane receptors in Escherichia coli; Konisky J et al.; Strains of Escherichia coli K-12 defective in their ability to utilize exogenously supplied iron due to genetic defects in the entF, tonB, fes, or fep gene exhibited elevated levels of the specific outer-membrane receptor for colicin Ia when compared with parental strains . Although entF, fes, and fep strains showed a higher degree of Ia sensitivity than did the parental strains, tonB strains were resistant to colicin action . The colicin insensitivity of tonB strains was not due to hyperproduction of enterochelin . Growth in medium containing 101.8 muM Fe2+ led to a lowering of receptor levels in all the above strains and resulted in decreased colicin Ia sensitivity in all strains except tonB, which was already at maximal resistance . Growth in citrate plus iron (1.8 muM) or in ferrichrome resulted in a substantial reduction in both receptor levels and Ia sensitivity in ent, fes, and fep strains but had no effect on receptor levels in tonB strains . Growth in citrate did not lead to an alteration in receptor levels in a mutant specifically defective in citrate-mediated iron transport . The presence of enterochelin during growth led to a reduction in the number of receptors in the parental and ent strains but not in tonB, fes, or fep strains . Thus, in all cases examined, there was an inverse relationship between the number of colicin receptors per cell and the ability of the strain to take up iron from the growth medium . This suggests that under conditions of iron limitation there is a derepression of colicin Ia receptor biosynthesis . These results may point to a role of the colicin I receptor in iron uptake.

Z Naturforsch {C}, 1976 Jul-Aug, 31(7-8), 468 - 78
Isolation and properties of yeast mutants with highly efficient thymidylate utilization; Fath WW et al.; A screening procedure is presented which allows the isolation of yeast mutants (typ tir) with highly efficient utilization of exogenous deoxythymidine-5'-monophosphate (5'-dTMP) (greater than 50%) . Data are given concerning the phenomenon of 5'-dTMP utilization in general: (i) The ability of S . cerevisiae to incorporate exogenous 5'-dTMP was found to already to be a wild type feature of this yeast, i.e . apparently not to be due to any mutation such as typ, tup, tmp, per or tum . Consequently these mutations are interpreted as amplifiers of a pre-given wild type potency . So far eight stages of 5'-dTMP utilization were detected as classified by the optimal 5'-dTMP requirement, with 5'-dTMP biosynthesis blocked, of the corresponding mutant strains isolated . All of them fit well into a mathematical series of the type "2n x 1.5" (n = 0, 1, 2, ..., 11), where the product term for n = 11 represents the 5'-dTMP requirement (mug/ml) of the best 5'-dTMP utilizing wild type strain found . (ii) Amplification of the 5'-dTMP utilizing potency obviously is due to any genetically determined alteration of the yeast 5'-dTMP uptaking principle itself or of physiological processes accompanying the monophosphate's uptake . (iii) The functioning of 5'-dTMP uptake requires acidic (less than or equal to pH 6) conditions in the yeast cell's outer environment . (iv) Some yeast typ and typ tlr mutants were found to exhibit a more or less pronounced sensitivity towards exogenously offered 5'-dTMP . The response of a sensitive strain towards inhibitory concentrations of the nucleotide apparently is co-conditioned by the presence or absence of thymidylate biosynthesis . With 5'-dTMP biosynthesis blocked the 5'-dTMP mediated inhibition is a permanent one and finally leads to the death of a cell . With a functioning thymidylate biosynthesis, in contrast, the inhibition is only temporary . (v) Yeast typ or typ tlr strains were observed to dephosphorylate exogenous 5'-dTMP to thymidine due to a phosphatase activity which cannot be eliminated at pH 7 + 70 mM inorganic phosphate conditions in the growth medium . This 5'-dTMP cleavage obviously occurs outside the cell and does not seem to be correlated both to the monophosphate's uptake and to the phenomenon of 5'-dTMP sensitivity . The destruction of 5'-dTMP does not disturb (5'-dTMP) DNA-specific labelling.

Biochemistry, 1976 Jun 29, 15(13), 2723 - 8
Fungal ornithine esterases: relationship to iron transport; Emery T; Extracts of Fusarium roseum (ATCC 12822) contain an enzyme which hydrolyzes the ornithine ester bonds of fusarinine C, a cyclic trihydroxamic acid produced by this organism . The methyl ester of Ndelta-dinitrophenyl-L-ornithine is also a substrate for the enzyme, and an assay was devised using this substrate . The enzyme exhibits a sharp maximum of activity at pH 7.5 and is extremely temperature sensitive . It is strongly inhibited by HgCl2 and p-chloromercuribenzoate, and it is competitively inhibited by Ndelta-dinitrophenyl-D-ornithine methyl ester (Ki = 0.3mM) . Methyl esters of glycine, L-alanine, dinitrophenyl-L-alanine, dinitrophenyl-beta-alanine, and Ndelta-dinitrophenyl-Nalpha-acetyl-L-ornithine are not substrates, although Nepsilon-dinitrophenyl-L-lysine methyl ester is as effective as the ornithine derivative . Nonspecific lipases do not hydrolyze ornithine esters, nor does trypsin . The three ester bonds of fusarinine C are progressively hydrolyzed by the enzyme to eventually yield the monomer, fusarinine . The ferric chelate of fusarinine C is not hydrolyzed . An enzyme from Penicillium sp . was isolated with identical properties toward Nbeta-dinitro-phenyl-L-ornithine methyl ester as substrate . It also hydrolyzes N,N',N"-triacetylfusarinine C, a cyclic trihydroxamate containing Nalpha-acetylornithine ester bonds, which is produced by this organism . This substrate is hydrolyzed to Nalpha-acetylfusarine . In contrast to the Fusarium enzyme, this enzyme is fully active toward the ferric trihydroxamate chelate . However, replacement of iron by aluminum leads to a completely inactive substrate . Production of the enzyme is severely suppressed by iron in the growth medium . It is proposed that these specific ornithylesterases provide a mechanism of cellular iron release by hydrolysis of the ferric ionophores, and that an iron-exchange step occurs prior to, and is a prerequisite for, hydrolysis of the ester bonds.

Biochemistry, 1976 Jun 15, 15(12), 2661 - 8
Regulation of ribosomal RNA synthesis and processing during inhibition of protein synthesis by 1,3-bis(2-chloroethyl)-1-nitrosourea; Penman M et al.; The antineoplastic agent BCNU (1,3-bis(2-chloroethyl)-1nitrosourea) at a concentration of 25 mug/ml inhibits initiation of protein synthesis in HeLa cells . At this low concentration of the drug, the rate of synthesis of 45S ribosomal precursor RNA (pre-rRNA) is selectively inhibited without a marked inhibition of nucleoplasmic RNA . The inhibitory effects of the drug are readily reversible upon removal of BCNU from the growth medium . Pulse-chase analysis of the labeled nucleolar RNA in sucrose-gradients and acrylamide gels indicated that the 45S pre-rRNA synthesized before the addition of BCNU matures normally in the presence of the inhibitor . However, the processing of precursor RNA molecules synthesized following the addition of the drug is inhibited when incubation is continued on in the presence of 25 mug/ml BCNU . Since the formation of mature ribosomes is blocked by BCNU, the data would suggest that the effectiveness of the drug as a potent cell growth inhibitor may result from its inhibition of ribosome formation induced by inhibition of protein synthesis.

Can J Microbiol, 1976 Jun, 22(6), 867 - 72
Repression of the acid phosphatase of Saccharomyces bisporus in relation to the polyphosphate content of the cells; Weimberg R; The relationship between the level of stored polyphosphate in growing cells of Saccharomyces bisporus and the repressing or derepression of the synthesis of the enzyme acid phosphatase (EC 3.1.3.2) was investigated . Time-course studies showed that there is no correlation between the cellular concentrations of either polyphosphate or orthophosphate and the ability of the cells to form this enzyme . The only compound investigated that was capable of repressing acid phosphatase synthesis was orthophosphate in the growth medium (i.e . orthophosphate outside the cell).

J Gen Microbiol, 1976 Jun, 94(2), 380 - 8
Cultural factors influencing the utilization or production of acetate by Butyrivibrio fibrisolvens; Latham MJ et al.; Utilization of acetate by four strains of Butyrivibrio fibrisolvens was influenced by the composition of their growth medium . Growth-limiting glucose concentrations, low availability of CO2 and the presence of sodium lactate all stimulated acetate uptake by three strains . The type strain, D1, utilized acetate if the concentration of acetate added to the medium was at least 15 mumol ml-1 . In batch culture, all strains produced acetate before entering a phase of acetate uptake . Continuous-culture studies with one strain showed that acetate uptake was dependent upon growth rate . The amount of n-butyrate produced in batch or continuous culture was closely linked to the amount of acetate taken up.

Bull Environ Contam Toxicol, 1976 Jun, 15(6), 665 - 9
Effect of aflatoxin B and rubratoxin B on bacteriophage and rabbit cornea cells; Hayes AW; Rabbit cornea cells exhibited a sensitivity to 1 mug aflatoxin B1 and 5 mug rubratoxin B per ml of growth medium . No changes were observed in the bacteriophages tested in the presence of 25 mug aflatoxin B1 or 100 mug rubratoxin B per ml of medium by the plaque-forming unit method or single-step growth curves.

Rev Esp Fisiol, 1976 Jun, 32(2), 91 - 4
Protection by GABA and succinic semialdehyde of seed germination and some enzymatic activities against high concentration of hydroxylamine; Canadas S et al.; Hydroxylamine was found to stimulate germination of Lupinus albus at concentrations inferior to 10 mM and to inhibit it greatly at 20 mM concentration . This inhibition was partially restored by GABA or succinic semialdehyde . Hydroxylamine, at high concentrations, behaved as inhibitor in vivo on GABA 2-oxyglutarate amino-transferase and succinic semialdehyde dehydrogenase NAD-dependent, whereas it behaved as activator on succinic semialdehyde dehydrogenase NADP-dependent . No effects were observed on the enzymatic activities and the inhibited germination was partially restored, after GABA and succinic semialdehyde had been added to a growth medium with a 20 mM hydroxylamine concentration . A possible protection mechanism of GABA and succinic semialdehyde against hydroxylamine action is discussed.

Infect Immun, 1976 Jun, 13(6), 1710 - 20
Partial purification and characterization of a heat-labile enterotoxin of Escherichia coli; Schenkein I et al.; A partially purified enterotoxin was obtained from the growth medium of Escherichia coli strain 711 (P307), a derivative of E . coli K-12, by ultrafiltration, precipitation with ammonium sulfate, molecular sieving, and anion exchange column chromatography . The active moiety, which is heat-labile, behaved like a protein particle of 180,000 to 200,000 daltons during molecular sieving and ultracentrifugation . During polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE), it dissociated into two subunits with apparent molecular weights of 68,000 to 70,000 and 14,000 to 15,000 . SDS-PAGE after heating in SDS changed the larger subunit to an apparent molecular weight of about 40,000; the smaller subunit did not change . The intact particle induced rounding of the cells in Y-1 mouse adrenal tumor cells used for assay . The detergent-dissociated molecules were not active . Proteolysis of the purified toxin by tolylsulfonyl phenylalanyl chloromethyl ketone-trypsin appeared to enhance its activity . The addition of serum to the assay medium resulted in partial depression of the activity . Activity was also abolished by preincubation of the toxin with either a rabbit antiserum to it or solutions containing GM1 ganglioside . The length of time needed to evoke a response in the assay system by fractions from different stages in the purification of the enterotoxin was a useful parameter in the evaluation of specific activity.

Clin Genet, 1976 Jun, 9(6), 545 - 52
Prenatal diagnosis of homoxygous familial hypercholesterolemia: investigation of a case at risk; Wienker TF et al.; Cultivated amnion cells obtained from a pregnancy at risk for the homozygous form of familial hypercholesterolemia were analyzed, as were fibroblasts from normal, heterozygous and homozygous controls . Three different methods were employed in order to compare their diagnostic value: i . Acetate incorporation into the cellular 3beta-OH-sterol fraction; ii . LDL-binding to the cell surface receptor; and iii . Oleate incorporation into the cholesterylester pool of the cells after addition of LDL to lipoprotein-deficient growth medium . The best discrimination between normal, heterozygous and homozygous cells was achieved using the third technique . On the basis of the acetate incorporation analysis, we concluded that the child is not homozygous, but probably completely unaffected . This diagnosis was confirmed by repeated determinations of plasma cholesterol levels during the first 11 months of life . Our investigations further substantiate the specularion that prenatal diagnosis of this disorder is possible.

J Bacteriol, 1976 Jun, 126(3), 1207 - 14
Carnitine biosynthesis in Neurospora crassa: enzymatic conversion of lysine to epsilon-N-trimethyllysine; Rebouche CJ et al.; The enzymatic conversion of L-lysine, epsilon-N-trimethyl-L-lysine the first series of reactions in the biosynthesis of carnitine in Neurospora crassa, proceeds via sequential methylation of free L-lysine, epsilon-N-methyl-L-lysine, and epsilon -N-dimethyl-L-lysine . The latter two compounds have been shown to be intermediates in the biosynthesis of carnitine by radioisotope dilution and incorporation experiments in growing cultures of N . crassa 33933 (lys-) and 38706 (met-) . Methionine but not choline, has been recognized as an effective methyl donor in vivo . Inclusion of choline in the growth medium of strain 33933 does, however, enhance incorporation of the methyl groups of L-{methyl-3H}methionine into carnitine in an apparent "sparing" effect on methionine synthesis . Studies in cell-free extracts of the lysine auxotroph strain 33933 of N . crassa have established that lysine and epsilon-N-methyl and epsilon-N-dimethyllysine are enzymatically methylated, with S-adenosyl-L-methionine as the methyl group donor . The enzyme system appears to have no essential cofactors . Lysine does not induce synthesis of the enzyme system in the wild-type strain 262, whereas both carnitine and epsilon-N-trimethyllysine repress its synthesis in strain 33933.

Eur J Biochem, 1976 Jun 1, 65(2), 317 - 24
Control of fatty-acid synthetase levels by exogeneous long-chain fatty acids in the yeasts Candida lipolytica and Saccharomyces cerevisiae; Meyer KH et al.; Endogeneous fatty acid biosynthesis in the two yeast species, Saccharomyces cerevisiae and Candida lipolytica is completely repressed by the addition of long-chain fatty acids to the growth medium . In Candida lipolytica, this repression is accompanied by a corresponding loss of fatty acid synthetase activity in the cell homogenate, when the cells were grown on fatty acids as the sole carbon source . The activity of the Saccharomyces cerevisiae fatty acid synthetase, however, remains unaffected by the addition of fatty acids to a glucose-containing growth medium . From fatty-acid-grown Candida lipolytica cells no fatty acid synthetase complex can be isolated, nor is there any immunologically cross-reacting fatty acid synthetase protein detectable in the crude cell extract . From this it is concluded that Candida lipolytica, but not Saccharomyces cerevisiae, is able to adapt to the growth on fatty acids either by repression of fatty acid synthetase biosynthesis or by a fatty-acid-induced proteolytic degradation of the multienzyme complex . Similarly, the fatty acid synthetase complex disappears rapidly from stationary phase Candida lipolytica cells even after growth in fatty-acid-free medium . Finally, it was found that the fatty acid synthetase complexes from Saccharomyces cerevisiae and Candida lipolytica, though very similar in size and subunit composition, were immunologically different and had no common antigenic determinants.

Biochim Biophys Acta, 1976 May 28, 428(3), 550 - 62
Transport and utilization of the biosynthetic intermediate shikimic acid in Escherichia coli; Brown KD et al.; Auxotrophic mutants of Escherichia coli W or K12 blocked before shikimic acid in the aromatic biosynthetic pathway grew poorly on shikimic acid as sole aromatic supplement . This poor growth response was correlated with a relatively poor ability to transport shikimic acid . If citrate was present in the growth medium (as it is in some commonly used basal media) the growth of some of the E . coli K12 mutants on shikimate was further reduced . Mutants were derived from pre-shikimate auxotrophs which grew rapidly on media containing shikimic acid . These derivatives all had an increased ability to transport shikimic acid . Thus, it is proposed that the growth on shikimate observed in the parent cells is restricted by their relatively poor uptake of shikimate from the medium and that this restriction may be removed by a mutation which enhances shikimate transport . Transduction analysis of the mutations which enhanced utilization and transport of shikimic acid by E . coli K12 strains indicated at least two classes . Class 1 was about 20% cotransduced with the histidine region of the E . coli K12 chromosome and appeared to be coincident with a known shikimate transport locus, shiA . Class 2 was not cotransduced with his . The locus (or loci) of this class is unknown . Kinetic measurements suggested that both classes had shikimate uptake systems derived from the wild-type system . Two class 1 mutants had increased levels of otherwise unaltered wild-type transport while one class 2 mutant had an altered Michaelis constant (Km) for shikimate transport.

Eur J Biochem, 1976 May 17, 65(1), 225 - 36
Partial purification and some properties of oxalacetase from Aspergillus niger; Lenz H et al.; 1 . Oxalacetase from Asperigillus niger was found to be an inducible enzyme, the induction being dependent not only on neutralisation of the acidic growth medium but also on the presence of carbonate . An explanation is proposed . 2 . Three methods were established for the quantitative determination of oxalacetase activity . These are based on the determination of the product acetate, on the absorbance of oxaloacetate and on coupling the hydrolysis of oxaloacetate to the oxidation of malate by NAD in the presence of malate dehydrogenase . 3 . Oxalacetase was purified about 50-fold from cell-free extracts of A . niger and used to determine some of its properties such as kinetic constants . 4 . 2S-{U-14C, 3-2H2} Malate in the presence of oxalacetase, NAD and malate dehydrogenase was partially converted to acetate and oxalate . The 3H/14C ratio of the isolated acetate was nearly twice as high as that of the malate used initially . The result demonstrates that the keto form of oxaloacetate, not the enol, is the substrate of the enzyme . 5 . Equimolecular mixtures of 2S, 3S-{3-2H1} malate + 2S-{2-2H1} malate (mixture 1) and 2S, 3R-{3-2H1, 3H1} malate + 2S, 3R-{2-2H1, 3-3H1} malate (mixture 2) were prepared from 2S-{3-3H2} malate by incubation with fumarase in normal and tritiated water, respectively . The isolated mixture 1, in the presence of oxalacetase, NAD and malate dehydrogenase was incubated in tritiated water for formation of acetate and oxalate; the isolated mixture 2 was treated likewise in normal water . 6 . The mixtures of symmetrically labelled {3H1} acetate and chiral acetates thus produced were isolated and the configuration of the {3H1, 3H1} acetate specimens was determined in the sequence acetate leads to malate leads to fumarate, as usual . The {2H1, 3H1} acetate derived from 2S, 3S-{3-2H1} malate (present in mixture 1( yielded a malate which on incubation with fumarase retained 65.0% of its total tritium content . This chiral acetate, therefore, had the R configuration . The {2H1, 3H1} acetate derived from 2S, 3R-{2-2H1, 3-3H1} malate produced a malate which retained 35% of its total tritium content, and therefore had the S configuration . 7 . It was concluded that the detachment of the oxaloyl residue from oxaloacetate and its replacement by a proton proceed with inversion of configuration at the methylene group which becomes methyl during the hydrolysis.

Mikrobiologiia, 1976 May-Jun, 45, 507 - 11
{Fine structure of Nocardia corallina oxidizing phenol}; Aristarkhova VI; Intracellular structures were detected in Nocardia corallina, strain 4, on a medium containing phenol as a sole source of carbon but not on a conventional growth medium (MPA) . The structures are light vacuoles containing granular and fibrillar electron-dense substance . The structures specific of this medium may be regions of phenol oxidation.

Mikrobiologiia, 1976 May-Jun, 45, 440 - 3
{Photochromogeneity of actinomycetes producing heliomycin}; Poltorak VA; Irradiation with solar rays of actinomycetes producing heliomycin changed the colour and UV-induced luminescence of the growth medium . This was caused by formation of a luminescent pigment, hydroxyquinone . The aerial mycelium reduced in spore formation acquired a pink colour.

In Vitro, 1976 May, 12(5), 393 - 8
Synchronization of some human cell strains by serum and calcium starvation; Griffin MJ; A technique was investigated for producing parasynchronous growth of some established, aneuploid human cell strains . Removal of both serum and calcium from exponentially growing monolayer cells tended to inhibit their growth . After 20 hr, a high percentage of the cell population was arrested in or near mitosis . Readdition of serum and calcium caused parasynchronous growth of the cells of three human strains studied . All three strains incorporated tritiated thymidine maximally 10 to 15 hr after serum and calcium were added, and cell numbers increased rapidly 17 to 25 hr after the growth medium was reconstituted . Population-doubling ranged from 80% to 100% of the theoretical . The yield of parasynchronous cells is high with this technique and may produce a significant amount of nontemporally distorted biological material upon which direct biochemical analysis can be performed at various times within the generation cycle.

Mikrobiologiia, 1976 May-Jun, 45, 429 - 32
{Effect of growth medium composition of glucoamylase and glycosyltransferase activity of Endomyces fibuliger}; Georgieva SI et al.; Production of glucoamylase and glycosyltransferase by Endomyces fibuliger was found to depend on sources of carbon and nitrogen nutrition . Starch at a concentration above 0.5% in the medium stimulated biosynthesis of glycosyltransferase but inhibited production of glucoamylase by End . fibuliger 20-9 . The rate of growth of the micro-organism increased by a factor of 3.3 with an increase of starch concentration from 0.5 to 6% . Synthesis of glycosyltransferase was repressed by glucose, lactose, sucrose and maltose . Synthesis of glucoamylase was repressed by lactose, sorbose and galactose . Synthesis of glycosyltransferase was stimulated by xylose, sorbose and galactose . Production of glucoamylase was stimulated by xylose and arabinose . Growth of the culture and synthesis of glucoamylase and maltase in the cultural broth were stimulated by an increase in the concentration of maize extract . Biosynthesis of glucoamylase and glycosyltransferase was stimulated by NH4H2PO4.

Appl Environ Microbiol, 1976 May, 31(5), 691 - 4
Growth of Fusarium moniliforme on carob aqueous extract and nutritional evaluation of its biomass; Drouliscos NJ et al.; Fusarium moniliforme was cultured semicontinuously on a carob medium in a 14-liter fermentor (8.5-liter working volume) . The growth medium provided 2.4% carob sugar, 0.72% NH4H2PO4, and 0.03% MgSO4-7H2O . The biomass harvest was 8.8 g/liter per day . Ninety percent of the sugars were consumed, and the pH dropped from 5.9 to about 3.7 . The crude protein (N X 6.25) of the spray-dried mycelium was 380 g/kg, 300 g/kg for the true protein (Lowry), and 4.8 g/kg for the (Folin-Denis) tannic acid . The mycelium was evaluated nutritionally with the weanling rat as experimental animal . The protein efficiency ratio and net protein utilization values for the unsupplemented mycelium were 1.15 and 0.42, respectively, and for the mycelium supplemented with DL-methionine (5 g/kg) they were 2.31 and 0.72, respectively . No growth depression was observed in the experimental rats, and on dissection of the carcasses the internal organs were found to be normal.

J Biol Chem, 1976 Apr 10, 251(7), 2119 - 23
Purification and properties of a highly potent antitumor glutaminase-asparaginase from Pseudomonas 7Z; Roberts J; Crystalline glutaminase-asparaginase which is effective against solid as well as ascites tumors was prepared from soil isolate organism Pseudomonas 7A . This enzyme has a ration of Vmax for L-glutamine and L-asparagine of 2.0 . The presence of glutamic acid in the growth medium is essential for optimal enzyme production and glucose inhibits the production of glutaminase-asparaginase . The purification procedure provides an overall yield of 40 to 45% from crude cell extract to homogeneous glutaminase-asparaginase and is adaptable to large scale production of the enzyme . The specific activity of homogeneous enzyme is 160 +/- 15 i.u./mg of protein and the E1% 280 is 9.8 . No disulfide or sulfhydryl groups appear to be present on the enzyme . The isoelectric point of glutaminase-asparaginase by isoelectric focusing on ampholine polyacrylamide gel plates is 5.8 . The Km values for L-glutamine and L-asparagine are 4.6 and 4.4 X 10(-6) M, respectively . The enzyme catalyzes the hydrolysis of the D isomers of glutamine and asparagine at 87 and 69% the rate of the respective L isomers . L-Glutamic acid gamma-monohydroxamate is hydrolyzed at approximately the same rate as L-glutamine . The enzyme is not inhibited by ethylenediaminetetraacetate (0.1 mM), L-glutamate (30 mM), or L-aspartate (30 mM) . Ammonium sulfate (10 mM) inhibits the enzymatic activity . The plasma half-life of Pseudomonas 7A glutaminase-asparaginase if 13 hours in normal mice and 43 hours in mice infected with the lactate dehydrogenase-elevating virus.

J Dairy Sci, 1976 Apr, 59(4), 643 - 7
Factors influencing rumen microbial growth rates and yields: effects of urea and amino acids over time; Maeng WJ et al.; Washed cell suspensions of mixed rumen bacteria were used to evaluate effects of 100% urea-nitrogen and 75% urea-nitrogen plus 25% amino acid-nitrogen in growth media upon microbial growth rate and yield, specific rate of glucose consumption, and incorporation of glucose into mixed cells, carbon dioxide, and end products . Rumen microbial dry matter, nitrogen, ribonucleic acid, deoxyribonucleic acid, glucose disappearance, and production of volatile fatty acids were considerably higher in medium containing urea plus amino acids as compared with urea only . Specific growth rates of microbes were .104 and .203 and mean doubling times were 6.7 and 3.4 h in the urea and urea plus amino acid growth media . Microbial growth in mg per 100 mg glucose used, per mole glucose and per mole adenosine triphosphate (ATP), and specific rate of glucose consumption in mmol per mg cells-h were 19.3, 34.7, 15.4, and .016 with urea, and 24.4, 44.2, 20.6, and .014 with urea plus amino acids . Percentages of catabolized glucose incorporated into microbial cells, carbon dioxide, and end products did not differ between treatments and averaged 19.5, 7.8, and 64.4%.

Bull Environ Contam Toxicol, 1976 Apr, 15(4), 447 - 53
Effect of some inhibitors on aflatoxin-production in a synthetic medium and on the incorporation of acetate-1- 14C into aflatoxins by resting mycelia of Aspergillus parasiticus; Gupta SR et al.; The effect of a number of metabolic inhibitors on the incorporation of acetate-1-14C into aflatoxins was investigated, using resting mycelia of Aspergillus parasiticus suspended in phosphate buffer . Malonate, iodoacetate, sodium arsenite, 2:4 dinitrophenol, sodium fluoride and p-aminosalicylate stimulated the incorporation at low concentrations and inhibited the same at high concentrations . p-Nitrobenzoic acid was inhibitory at all the concentrations tried . Fluoride, arsenite, arsenate and iodoacetate inhibited both growth and aflatoxin production when added directly to the growth medium . In general, there was a greater inhibition in growth medium than with the suspended mycelia.

J Natl Cancer Inst, 1976 Apr, 56(4), 871 - 3
Murine colon adenocarcinomas: methods for selective culture in vitro; Tan MH et al.; Two murine colon adenocarcinoma cell lines were established from primary cultures . The MCA-38 cell line was begun by treatment of the primary culture with trypsin to remove the fibroblastoid elements . The MCA-36 epithelial cells were sensitive to trypsin; therefore, the growth medium of MCA-36 primary cultures was augmented with collagenase to release the tumor-cell elements from the fibroblast network . These tumor elements were dissociated with trypsin and placed in tissue culture . Each cell line was cultured for at least 10 passages in vitro and gave rise to tumors when reimplanted in vivo.

Rev Ig Bacteriol Virusol Parazitol Epidemiol Pneumoftiziol Bacteriol Virusol Parazitol Epidemiol, 1976 Apr-Jun, 21(2), 111 - 20
{Production and characterization of some mouse embryo cellular substrates in vitro}; Voiculescu C et al.; Cell cultures with a different multiplication potential in vitro, depending upon the strain source used, were obtained from mouse embryos belonging to the CVA, C57 Black A2G and Swiss strains . Only the Swiss 12 culture underwent spontaneous transformation and was carried through more than 50 passages in vitro . The Swiss-12 substrate proved not to be contaminated either by viruses or micoplasma . It is less sensitive than other elective cell substrates to infection with attenuated polioviruses, cytopathogenic Coxsackie A9 virus and vaccinia virus, but its sensitivity to infection with Herpes simplex type 1 virus is similar to that of human embryo fibroblasts . After a high number of passages the Swiss-12 substrate permits, in comparison to other cell substrates (human heteroploid Hep-2 line, human embryo fibroblasts), a highly efficient qualitative differentiation between the growth media and calf serum.

J Clin Endocrinol Metab, 1976 Apr, 42(4), 653 - 60
Familial true hermaphorodism in three siblings: plasma hormonal profile and in vitro steroid biosynthesis in gonadal structures; Gallegos AJ et al.; The in vitro biosynthesis of estrogens and androgens by gonadal tissues of the ovotestes was studied in three siblings with familial true hermaphrodism and correlated with daily steroid and gonadotropin plasma levels . The probands were 15, 13, and 11 years old with normal male phenotype and external genitalia, grade III hypospadias, bilateral scrotal ovotestes, gynecomastia, and no uterus or fallopian tubes . Their karyotypes were 46XX both in peripheral lymphocytes and in gonadal fibroblasts, and no Y chromosome fluorescence was observed . A fusiform biopsy of each gonad was obtained, and the testicular and ovarian structures were excised and incubated for five days at 37 C with 3.8 muCi of 7alpha3H dehydroepiandrosterone, in Eagle's growth media, 95% O2 and 5% CO2 . After standard procedures, four extractions with methylene chloride were performed, and the residue was assayed using Sephadex LH no . 20 chromatography . Testosterone (T), delta4androstenedione (delta 4), 5alphadehydrotestosterone (5alphaDHT), estrone (E1), estradiol-17 beta (E2) and estriol (E3) were measured . Also, during 16 consecutive days daily venous samples were obtained, and FSH, LH, E2, progesterone (P), and testosterone (T) were determined . The predominant steroids formed in vitro were estrogens, mainly E1 by either the testicular or ovarian structures . In the 11-year-old subject, the ovotestes were less active than in his oldest siblings . The patterns of androgen production showed that T was the principal androgen formed, followed by delta4 and minimal amounts of 5alphaDHT . The daily plasma hormonal profile resembled more closely a female pattern, specially in the 15 and 13-year-old patients . It is suggested that the ovotestes of these siblings had the enzymatic mechanisms necessary for estrogen and androgen biosynthesis, mainly E1 and T using a preferential metabolic pathway via androstenedione . Furthermore, it seems that the testicular structures had a greater capability to synthesize estrogens than the ovary.

Biochem J, 1976 Apr 1, 155(1), 87 - 99
The mechanism of sensitivity to phleomycin in growing Escherichia coli cells; Sleigh MJ et al.; Stationary-phase Escherichia coli B cells transferred to new growth medium are initially resistant to net DNA breakage by low concentrations of phleomycin, and become sensitive as DNA replication commences . From studies with inhibitors of various stages of the DNA replication cycle it is evident that it is not DNA synthesis itself that is required for induction of DNA breakage by phleomycin, but events associated with the initiation of DNA replication . Termination of replication in the absence of further initiaiton results in resistance to phleomycin . The cellular change responsible for changes in sensitivity to phleomycin could be the attachment of the bacterial chromosome to the cell membrane at initiation and detachment on termination of replication, suggesting an alteration in the balance between cellular DNA breakage and repair processes for membrane-associated compared with non-membrane-associated DNA.

J Bacteriol, 1976 Apr, 126(1), 232 - 42
Control of inositol biosynthesis in Saccharomyces cerevisiae: properties of a repressible enzyme system in extracts of wild-type (Ino+) cells; Culbertson MR et al.; Inositol biosynthesis was studied in soluble, cell extracts of a wild-type (Ino) strain of Saccharomyces cerevisiae . Two reactions were detected: (i) conversion of D-glucose-6-phosphate to a phosphorylated form of inositol, presumably inositol-1-phosphate (IP synthethase, EC5.5.1.4), and (ii) conversion of phosphorylated inositol to inositol (IP phosphatase, EC3.1.3.25) . The in vitro rate of conversion of glucose-6-phosphate to inositol was proportional to incubaion time and enzyme concentration . The pH optimum was 7.0 . The synthesis of inositol required oxidized nicotinamide adenine dinucleotide (NAD) and was stimulated byNH4C1 and MgC12 . NADP substituted poorly for NAD, and NADH inhibitedthe reaction . Phosphorylated inositol accumulated in the absence of MgC12, suggesting that inositol-phosphate is an intermediate in the pathway and that Mg ions stimulate the dephosphorylation of inositol-phosphate . IP synthetase was inhibited approximately 20% in the presence of inositol in the reaction mixture at concentrations exceeding 1 mM . The enzyme was repressed approximately 50-fold when inositol was present in the growth medium at concentrations exceeding 50 muM . IP synthetase reached the fully repressed level approximately 10 h after the addition of inositol to logarithmic cultures grown in the absence of inositol . The specific activity of the enzyme increased with time in logarithmically growing cultures lacking inositol andapproached the fully depressed level as the cells entered stationary phase.

Eur J Biochem, 1976 Apr 1, 63(2), 533 - 41
The proton electrochemical gradient in Escherichia coli cells; Padan E et al.; The internal pH of Escherichia coli cells was estimated from the distribution of either 5,5-{14C}dimethyl-2,4-oxazolidinedione or {14C}methylamine . EDTA/valinomycin treatment of cells was employed to estimate delta psi from 86Rb+ distribution concomitant with the delta pH for calculation of delta muH . Respiring intact cells maintained an internal pH more alkaline by 0.63-0.75 unit than that of the milieu at extracellular pH 7, both in growth medium and KCl solutions . The delta pH decreased when respiration was inhibited by anaerobiosis or in the presence of KCN . The delta muH, established by EDTA/valinomycin-treated cells, was constant (122-129 mV) over extracellular potassium concentration of 0.01 mM-1 mM . At the lower potassium concentration delta psi (110-120 mV) was the predominant component, and at the higher concentration delta pH increased to 0.7 units (42 mV) . At 150 mM potassium delta muH was reduced to 70 mV mostly due to a delta pH component of 0.89 (53 mV) . The interchangeability of the delta muH components is consistent with an electronic proton pump and with potassium serving as a counter ion in the presence of valinomycin . Indeed both parameters of delta muH decreased in the presence of carbonylcyanide p-trifluoromethoxyphenylhydrazone . The highest delta pH of 2 units was observed in the intact cells at pH 6; increasing the extracellular pH decreased the delta pH to 0 at pH 7.65 and to -0.51 at pH 9 . A similar pattern of dependence of delta pH on extracellular pH was observed in EDTA/valinomycin-treated cells but the delta psi was almost constant over the whole range of extracellular pH values (6-8) implying electroneutral proton movement . Potassium is specifically required for respiration of EDTA-treated E . coli K12 cells since other monovalent or divalent cations could not replace potassium and valinomycin was not required.

Can J Microbiol, 1976 Apr, 22(4), 443 - 9
Effect of variou cultural conditions on the fatty acid and lipid composition of Choanephora cucurbitarum; Deven JM et al.; The fatty acid composition of the total and polar lipid fractions of Choanephora cucurbitarum grown under different cultural conditions were analyzed by thin-layer and gas-liquid chromatography . It was observed that temperature, age, pH, and light influenced the degree of unsaturation, this being due mainly to changes in the gamma-linolenic acid concentration . The conditions used in this study did not alter the qualitative profile of fatty acids normally present in the organism . Neither did these conditions stimulate the production of further long-chain fatty acids (C20-C26) beyond gamma-linolenic acid (C18:3) as reported earlier using growth media containing glutamic acid . The fatty acid pattern of lipid fractions though the same qualitatively, differed quantitatively . The polar lipid fractions, phosphatidyl choline, phosphatidyl ethanolamine, and diphosphatidyl glycerol showed an appreciable variation in gamma-linolenic acid content under different cultural conditions . The degree of unsaturation of the various lipid fractions decreased with increases in temperature, light intensity, and pH, but within each treatment the same pattern of decreasing degree of unsaturation with increasing age was observed . The significance of these observations is discussed.

Mol Gen Genet, 1976 Mar 30, 144(3), 253 - 62
Factors affecting petite induction and the recovery of respiratory competence in yeast cells exposed to ethidium bromide; Hall RM et al.; When growing cultures of S . cerevisiae are treated with high concentrations of ethidium bromide (greater than 50 mug/ml), three phases of petite induction may be observed: I . the majority of cells are rapidly converted to petite, II . subsequently a large proportion of cells recover the ability to form respiratory competent clones, and III . slow, irreversible conversion of all cells to petite . The extent of recovery of respiratory competence observed is dependent on the strain of S . cerevisiae employed and the temperature and the carbon source used in the growth medium . The effects of 100 mug/ml ethidium bromide are also produced by 10 mug/ml ethidium bromide in the presence of the detergent, sodium dodecyl sulphate, and recovery is also observed when cells are treated with 10 mug/ml ethidium bromide under starvation conditions . Genetic analysis of strain differences indicates that a number of nuclear genes influence petite induction by ethidium bromide . In one strain, S288C, petite induction by 100 mug/ml ethidium bromide is extremely slow under certain conditions . Mitochondria isolated from from S288C lack the ethidium bromide stimulated nuclease activity found in D243-4A, a strain which shows triphasic kinetics of petite formation . This enzyme may, therefore, be responsible for the initial phase of rapid petite formation.

Mol Gen Genet, 1976 Mar 22, 144(2), 223 - 30
Genetic and biochemical studies of phosphomannose isomerase deficient mutants of Saccharomyces cerevisiae; Herrera LS et al.; Three mannose-negative mutants of Saccharomyces cerevisiae have been isolated . These mutants showed growth inhibition when mannose was added to a growth medium containing glycerol or fructose . Crosses between wild type mutants showed segregation of 2+/2- . Crosses between the mutants themselves showed that they were closely linked . Two mutants (XM3 and D2) showed characteristics of allelic structural alteration of phosphomannoseisomerase . Mutant D4 had a deficiency of phosphomannoseisomerase activity, but with a normal thermostability . Revertants from D4 had a normal thermostability.

Experientia, 1976 Mar 15, 32(3), 322 - 4
Cellular control of the tick-borne virus antigen production in persistently infected cell culture; Boriskin YS et al.; The influence of inhibition or stimulation of cellular DNA synthesis on tick-borne virus antigen production in persistently infected cell culture was studied . Either mitomycin C or cytosine-arabinoside caused cessation of antigen-containing cell number increase . Stimulation of cellular DNA synthesis by growth medium change increased the level of antigen-containing cells . When HEp-2-Sof culture was synchronized, a correlation was observed between the entrance of cells into DNA synthesis phase and the increase of proportion of antigen-containing cells.

J Bacteriol, 1976 Mar, 125(3), 946 - 54
Lipid composition and lipid metabolism of Spiroplasma citri; Freeman BA et al.; In a horse serum-based medium containing a full complement of fatty acids, cells of Spiroplasma citri were seen to preferentially incorporate palmitic acid . In the same medium, which had a steryl ester-to-sterol ratio of 3.64, a steryl ester-to-sterol ratio of 0.23 was seen in the cells, cholesterol being preferentially incorporated over cholesteryl ester . Like most other mycoplasmas, S . citri was shown to be unable to synthesize fatty acids or esterify cholesterol . The neutral lipids of S . citri grown in a medium containing horse serum consisted of free cholesterol, cholesteryl ester, free fatty acids, triglycerides and diglycerides . All polar lipids were phospholipids, with no glycolipids detected . These phospholipids, which are characteristic of many mycoplasmas, are phosphatidyl glycerol, diphosphatidyl glycerol, and their lyso derivatives . Sphingomyelin was also incorporated when cells were grown on horse serum . A sterol requirement for the growth of S . citri was confirmed using a serum-free medium supplemented with bovine serum albumin, palmitic acid, and various concentrations of sterols dissolved in Tween 80 . The addition of palmitic acid stimulated growth but was not essential for growth . S citri was shown to grow best on cholesterol and beta-sitosterol and was able to grow on stigmasterol and ergosterol to a lesser degree . No growth was obtained using mevalonate, deoxycholate, or taurodeoxycholate as an alternative to sterol . S . citri was also able to grow when palmitic acid was replaced with oleic acid, linoleic acid, or linolenic acid . Alterations in the lipid composition of the growth medium and hence in the lipid composition of S . citri induced changes in the characteristic helical morphology of the cells, concurrent with loss of cell viability . Culture, age, and pH were also factors in determining cell morphology and viability.

Can J Microbiol, 1976 Mar, 22(3), 354 - 8
Studies on cardiolipin biosynthesis in Mycobacterium smegmatis; Mathur AK et al.; Supplementation of a growth medium with 5% glucose has been found to stimulate the formation of cardiolipin and phosphatidylethanolamine five- and threefold, respectively, in Mycobacterium smegmatis . The presence of both cytidine diphosphate diglyceride and phosphatidylglycerol pathways of biosynthesis of cardiolipin in cell-free extracts has been demonstrated . The enzymes were localized in the fractions which contained membranes . Isonicotinic acid hydrazide and streptomycin sulfate inhibited the formation of cardiolipin.

J Pharm Sci, 1976 Mar, 65(3), 362 - 6
Biosynthesis of deuterated riboflavin: structure determination by NMR and mass spectrometry; Pluta PL et al.; The riboflavin-producing fungus Eremothecium ashbyii was cultured in various growth media containing high concentrations of deuteriuj, and the product was isolated . The structures of highly deuterated riboflavin, in which at least 13 of 15 nonexchangeable hydrogens were replaced by deuterium, and fully deuterated riboflavin, in which all 15 nonexchangeable sites contained deuterium, were established by NMR and mass spectrometry . The aromatic protons (C-5 and C-8) wer partially substituted in the highly deuterated molecule . Information regarding three areas of the biosynthetic pathway within the microorganism was obtained as a result of the formation of these compounds . Extensive solvent interaction, possibly due to passage of sugar through the transaldolase-transketolase pathway, occurs during formation of the ribityl chain . Limited solvent participation takes place during formation of 6,7-dimethyl-8-ribityllumazine, the immediate precursor of riboflavin . Deuteration of the riboflavin C-6 and C-7 methyl groups indicates significant solvent exchange during the final step of the biosynthetic process.

J Bacteriol, 1976 Mar, 125(3), 1148 - 55
In vivo transcription of R-plasmid deoxyribonucleic acid in Escherichia coli strains with altered antibiotic resistance levels and/or conjugal proficiency; Davis R et al.; The amounts of plasmid deoxyribonucleic acid (DNA) and the levels of the in vivo transcription of the Escherichia coli plasmids R538-1 (repressed for conjugal transfer) and R538-1drd (derepressed for transfer) were determined by DNA-DNA hybridization and DNA-ribonucleic acid hybridization, respectively . The results demonstrate that the level of plasmid transcription is increased by two-fold in the strain carrying the derepressed plasmid, compared to an isogenic strain carrying the repressed plasmid, whereas the amount of plasmid DNA is approximately the same, suggesting that the transfer genes are under transcriptional control . Levels of plasmid DNA, plasmid DNA transcription, and chloramphenicol acetyltransferase activity were also compared in a mutant strain that carried the R538-1drd plasmid and was resistant to high levels of antibiotics . This strain produces about 13 copies of plasmid DNA per chromosome compared to five copies for the parent strain . The level of transcription of plasmid DNA was found to be twofold higher in the high-level resistant strain, whereas the level of chloramphenition, acetyltransferase activity was increased by 10-fold . In addition the levels of plasmid DNA transcription and chloramphenicol acetyltransferase activity in the high-level resistant strain were found to be further increased by the presence of high levels of chloramphenicol in the growth medium . The amount of plasmid DNA remained constant under these conditions, indicating that high levels of chloramphenicol can stimulate the expression of plasmid genes at the level of transcription in this strain.

Pediatr Res, 1976 Mar, 10(3), 179 - 83
Cobalamins in fibroblasts cultured from normal control subjects and patients with methylmalonic aciduria; Linnell JC et al.; The intracellular content and proportional distribution of B12 (cobalamin) derivatives in fibroblasts cultured from patients with various forms of methylmalonic aciduria, as well as from normal control subjects, has been determined by a two-dimensional chromatobioautographic technique . Each line of fibroblasts was grown in the presence of four concentrations of cobalamin, ranging from the 0.04-0.07 pmol/ml contained in the basal medium to 74 pmol/ml (100 ng/ml), added in form of hydroxocobalamin (OH-CHl) . Control cells grown in the basal medium contained substantial proportions of both methylcobalamin (MeCbl) and adenysylcobalamin (AdoCbl), with the former predominating . As increasing concentrations of OH-CBl were added to the growth medium, the total cellular cobalamin content increased without marked changes in the relative proportions of MeCbl, AdoCbl, and OH-Cbl . Three different patterns were discernable in the cobalamin distributions of the cells cultured from patients with methylmalonic aciduria (Table 1 and Fig . 1).

Biochim Biophys Acta, 1976 Feb 24, 421(2), 395 - 405
{Study of the formation of N-glycolylmuramic acid from Nocardia asteroides (author's transl)}; Gateau O et al.; Nocardia asteroides was grown in Sauton medium containing sodium {carboxy-14C}acetate . The biosynthesis of the peptidoglycan was inhibited by adding penicillin or phosphonomycin to the growth medium . These antibiotics give an accumulation of radioactive nucleotidic precursors of the peptidoglycan . In the presence of penicillin, there was an accumulation of uridine diphosphate-N-glycolylmuramyl peptide (UDP-MurNGlyc peptide) and of a mixture of uridine diphosphate-N-acetyl and N-glycolylmuramic acid (UDP-MurNAc) and UDP-MurNGlyc) . In the presence of phosphonomycin, the biosynthesis of muramic acid was blocked and there was an accumulation of uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) and uridine diphosphate-N-glycolyglucosamine (UDP-GlcNGlyc) . Thus the formation of a N-glycolyl group can be performed upon the neucleotidic derivatives of glucosamine and muramic acid . However in the peptidoglycan synthesized in vivo in the absence of antibiotic, only muramic acid was glycolyated . So, glycolylation seems to take place essentially on UDP-MurNAc . When the binding of peptide chain to muramic acid is achieved, all the muramic acid is glycolylated, then the polymerisation of glycan and peptidoglycan units by the mean of particulate enzymes is carried out on the N-glycolylated derivative of muramic acid . A cell-free preparation from Nocardia asteroides was obtained which can hydroxylate the acetyl group of UDP-MurNAc . The activity was localised in the soluble fraction . This system acts as a hydroxylase and requires the presence of NADPH.

J Pharm Sci, 1976 Feb, 65(2), 210 - 5
Effect of dimethyl sulfoxide on permeability of human skin in vitro; Astley JP et al.; A diffusion flow cell is described for the continuous monitoring of skin permeability . The technique was used to study the permeability behavior of human skin subsequent to treatment with dimethyl sulfoxide . Such treatment produced an increased penetration rate of tritiated water, which was dependent upon the time of exposure and the concentration of dimethyl sulfoxide applied . Removal of the solvent resulted in partial recovery of barrier capacity . Skin, incubated in vitro in growth medium containing dimethyl sulfoxide, survived only at very low concentrations . Degeneration occurred after a few days in 4.5% dimethyl sulfoxide and much sooner at higher concentrations.

J Gen Microbiol, 1976 Feb, 92(2), 246 - 50
Phagocytosis and pinocytosis in Acanthamoeba castellanii; Chambers JA et al.; Endocytotic activity of Acanthamoeba trophozoites attenuates once the cells enter stationary phase in liquid culture . Phagocytosis, monitored by the ingestion of polystyrene latex beads, essentially ceases and the uptake of {3H}inulin, known to be mediated by pinocytosis, is reduced by about half . The reduced pinocytotic activity of stationary-phase cells remains sensitive to respiratory inhibitors . Preincubation of stationary-phase cells in fresh growth medium for 1-5 h before the initiation of endocytosis has no effect on phagocytosis and only marginally increases pinocytosis . This impairment of ingestion, particularly of pinocytosis, may account for the reduced contractile vacuole activity known to characterize stationary-phase cells of this organism . The unequal responses of phagocytosis and pinocytosis to the onset of stationary-phase growth suggest that they are independent processes subject to different controls.

Am J Vet Res, 1976 Feb, 37(2), 211 - 4
Evolution and taxonomy in the genus Brucella: progesterone induction of filterable forms of Brucella abortus type 2 with revertant characteristics essentially indistinguishable in vitro from those of Brucella ovis; Meyer ME; An organism essentially indistinguishable from Brucella ovis, as determined by conventional and manometric techniques of identifying Brucella organisms, was derived in vitro from a strain of Brucella abortus type 2 . The basic mechanism responsible for derivation of this organism was incomplete reversion of the L-forms to their original parental characteristics . The agent used to induce the L-forms was a physiologic concentration of progesterone incorporated in the growth medium.

Am J Vet Res, 1976 Feb, 37(2), 207 - 10
Evolution and taxonomy in the genus Brucella: steroid hormone induction of filterable forms with altered characteristics after reversion; Meyer ME; Several strains of Brucella abortus, Brucella suis, and Brucella melitensis were exposed to physiologic concentrations of testosterone, progesterone, and diethylstilbestrol by incorporating them into the growth medium . The hormones induced Brucella to form cell wall-defective organisms, including filterable forms . The filterable forms from 1 strain of B melitensis had altered characteristics when it reverted to growth as an intact cell . This is the 1st reported instance of induction of filterable forms of Brucella by progesterone, testosterone, and diethylstilbestrol.

Biokhimiia, 1976 Feb, 41(2), 369 - 75
{Changes in mitochondrial heterogenicity during aerobic growth of Saccharomyces cerevisiae yeasts}; Bakalkin GIa et al.; Distribution of the activities of some mitochondrial enzymes after sucrose density gradient ultracentrifugation of cell homogenates of S . cerevisiae in the early and late exponential growth phases is studied . It is demonstrated that young yeast cells have a characteristic complex distribution of NADH oxidase (cyanide-sensitive), succinate:ferricyanide-oxidoreductase (or succinate:2,6-dichlorophenol indophenol-oxidoreductase), NADH:2,6-dichlorophenol indophenol-oxidoreductase and cytochrome oxidase activities in sucrose density gradient; the distribution patterns of these activities are different . All the above activities are detected in a single relatively narrow band in mature yeast cells . Similar results are obtained in the experiments with glucose or galactose as a carbon source in the yeast growth media . The Arrhenius plots for NADH oxidase (as well as for succinate:2,6-dichlorophenol indophenol-oxidoreductase) activity do not differ in the case of "light" and "heavy" mitochondrial structures characteristic of yeast cells in the early exponential growth phase . Nevertheless, "light" and "heavy" mitochondrial structures differ with respect of the arrangement of certain respiratory chain components in their membranes NADH-dehydrogenase and cytochrome oxidase) . This conclusion is drawn from the results obtained in the study of the interaction of the two types of structures with Fe(CN)6(3-), a non-penetrating ion and the antiserum to yeast mitochondria.

J Lab Clin Med, 1976 Feb, 87(2), 198 - 205
The effect of environmental pH on glycosaminoglycan metabolism by normal human chondrocytes; Schwartz ER et al.; The synthesis and release of sulfated glycosaminoglycans by normal human chondrocytes in culture are markedly affected by environmental pH . The biosynthetic rate is increased threefold as the pH of the growth medium is raised from 7.0 to 8.0 . This coincides with a corresponding elevation in total protein and cell growth . The rate of release of newly synthesized sulfated glycosaminoglycans from the cell layer as well as their distribution between intra- and extracellular localization in the cell layer is also modulated by environmental pH . At pH 8, 35 per cent is found within the cells, this value is reduced to 13 per cent at pH 7 . Pulse-chase experiments showed that previously incorporated sulfated proteoglycans were released at a faster rate at pH 7 than at pH 8 . The data suggest that proton concentrations affect the biosynthesis and the mode of distribution of newly synthesized sulfated glycosaminoglycans.

J Bacteriol, 1976 Feb, 125(2), 608 - 15
Derepression of certain aromatic amino acid biosynthetic enzymes of Escherichia coli K-12 by growth in Fe3+-deficient medium; McCray JW Jr et al.; 3-Deoxy-arabino-heptulosonic acid 7-phosphate synthase, prephenate dehydratase, tryptophan synthase, and 2,3-dihydroxybenzoylserine synthase enzyme activities are derepressed in wild-type Escherichia coli K-12 cells grown on Fe3+-deficient medium . This derepression is reversed when FeSO4 is added to the growth medium . Addition of shikimic acid to the Fe3+-deficient growth medium caused repression of the first three enzyme activities but not of 2,3-dihydroxybenzoylserine synthase activity . Addition of 2,3-dihydroxybenzoic acid to the Fe3+-deficient growth medium has no effect on any of the above-mentioned enzyme activities . The Fe3+ deficiency-mediated derepression of 3-deoxyarabino-heptulosonic acid 7-phosphate synthase activity is due to an elevation of the tyrosine-sensitive isoenzyme; the phenylalanine-sensitive isoenzyme is not derepressed under these conditions.

What Is Staphylococcus Aureus?, What Is Biotechnology?, What Is Cell Biology?, What Is Biofilter?, What Is Dna?, a, Bacteria, r, Microbiology, r, Microbe, o, Microorganism, c, Microorganisms, c, Bactericidal, s, Microbial, r, Yeasts, s, Antibiotics, e, Multidrug resistant, n, Staphylococcus, c, Cell suspensions, c, Antimicrobials, n, Salmonella, c, Bacteriological, o, Bacteria, e, Eutrophicated, e, Escherichia coli, a, Salmonella typhimurium, e, Eubacter, e, Enterobacteriacea, o, Enterobacteriacea, n, Gram positive, r, Escherichia coli, r, Yeasts, i, Bacillus

Scientific Publications - Work Done by Microbiology Reader Bioscreen C
Agricultural Microbiology Anaerobic Microbiology Antimicrobial Susceptibility Artificial Atmosphere Bioassay of Antibiotics Biofilm Microbiology Bioreactor Technology Biotechnology Cell Biology Clinical Microbiology Environmental Microbiology Experiments with Yeast	Fermentation Food Microbiology Functional Genomics Gene Technology Growth Media Development Growth Rate and Lag Time Industrial Microbiology Medical/Pharmaceutical Field Microbiological Assay Microbiological Research Microbiology of Cosmetics go to a specific theme...	Military Microbiology Molecular Microbiology Mutagenicity and Genotoxicity Oral Microbiology Patents Postantibiotic Studies Soil Microbiology Spore Microbiology Veterinary Microbiology Waste/Wastewater Treatment Water Microbiology Wine Microbiology

� 2005 Transgalactic Ltd (manufacturer of Bioscreen C software) | Privacy Statement | P.O. Box 1393, 00101 Helsinki, Finland, phone: +358 9 85172920, fax: +358 9 8749481, e-mail: microbiology@bionewsonline.com

Last modified: May 25, 2005