J Vasc Surg, 1986 Apr, 3(4), 649 - 51 Successful management of Histoplasma capsulatum infection of an abdominal aortic aneurysm; Harris RL et al.; A 65-year-old woman with disseminated histoplasmosis underwent resection of an atherosclerotic abdominal aortic aneurysm . Yeast forms of Histoplasma capsulatum were present in the aneurysm . Surgical resection and revascularization with a Dacron graft followed by systemic amphotericin B therapy and chronic ketoconazole suppressive therapy have resulted in a patient without symptoms 15 months postoperatively . It is important to be aware of the potential for artherosclerotic aortic aneurysm involvement by H . capsulatum. Appl Environ Microbiol, 1986 Apr, 51(4), 821 - 4 Effect of culture conditions on tremorgen production by some Penicillium species; di Menna ME et al.; Four strains each of seven tremorgenic Penicillium species were grown under various conditions and tested for tremorgen production by intraperitoneal injection of mice and by chemical analysis . Half of the strains had previously been found to be tremorgenic on bioassay after growth on Czapek Dox yeast extract broth or potato-milk-sucrose broth for 3 weeks at 26 degrees C . In the tests reported here nearly all previously nontremorgenic strains were either tremorgenic to mice or produced tremorgens detectable by chemical analysis but did so after longer incubation periods than used in the original screening . Bioassay was not suitable for the estimation of absolute levels but was preferable to chemical analysis when the identity of the tremorgens was not known . Species and strains within species gave different responses to changes in culture medium, incubation temperature, light irradiation, and shaking . Overall, tremorgen production was maximal at 20 or 26 degrees C, increased with time, and was reduced in shaken culture. Mol Immunol, 1986 Apr, 23(4), 433 - 40 Role of the N-terminal regions of hog C3a, C5a and C5a-desArg in their biological activities; Damerau B et al.; The N-terminal regions of the complement peptides C3a, C5a and C5a-desArg (purified from yeast-activated hog serum) were gradually shortened by incubation with leucine amino peptidase . This treatment led to the following changes in the biological activities of these peptides: the potencies of C5a and C5a-desArg in aggregation of human polymorphonuclear leukocytes and of guinea-pig platelets, and their ability to deactivate these cells were gradually diminished; the chemotactic effect of C5a-desArg on human leukocytes was similarly lowered, while the chemotactic potency of C5a was even increased up to the loss of the first 12 N-terminal amino acids . However, after removal of the whole N-terminal region (i.e . 20 amino acids distal of the first disulfide bridge) the potency of both peptides was decreased to a few percent . In contrast, C3a totally lost its platelet-aggregating as well as deactivating activity already after cleavage of 10-15 N-terminal amino acids by LAP . On leukocytes, on the other hand, C3a retained some activity even after the loss of the whole N-terminal region . These results indicate that the N-terminal regions play an important role for biological activities of the three complement peptides, possibly by stabilizing the optimal conformation of their C-terminal regions which contain the receptor-activating domains. J Antimicrob Chemother, 1986 Apr, 17 Suppl B, 53 - 7 Effects of pefloxacin on phagocytosis function of rat macrophages and polymorphonuclear leucocytes; Desnottes JF et al.; The influence of pefloxacin on polymorphonuclear leucocytes (PMN) and alveolar macrophages (AM) phagocytosis and microbicidal activity was studied . Phagocytes were collected from Sprague-Dawley rats, mixed with pefloxacin at different concentrations (1, 10, 100 mg/l) and a yeast phagocytosis assay was performed . Three parameters were measured, the phagocytic capacity (number of live and dead yeast/100 cells), the phagocytic activity (number of cells containing 2 or more yeast/100 cells) and the microbicidal activity or % killed (Formula: see text) Both low and high concentrations of pefloxacin increased significantly the phagocytic capacity and activity of AM and PMN . The increase of the AM phagocytic capacity and activity seen with increasing levels of extracellular pefloxacin was not statistically significant . Pefloxacin showed no adverse effect on the microbicidal activity of AM and PMN. Proc Natl Acad Sci U S A, 1986 Apr, 83(8), 2501 - 5 Identification of the macrophage mannose receptor as a 175-kDa membrane protein; Wileman TE et al.; Mannose-lactoperoxidase, a neoglycoprotein prepared by reaction of lactoperoxidase with cyanomethyl 1-thiomannoside, bound to alveolar macrophages at 4 degrees C (Kd = 5.8 X 10(-8) M) and was rapidly internalized at 37 degrees C (K uptake = 2 X 10(-8) M) . Mannose-lactoperoxidase binding and uptake were blocked by yeast mannan, and mannose-lactoperoxidase inhibited uptake of 125I-labeled mannose-BSA (bovine serum albumin) . Radioiodination of cells with surface-bound mannose-lactoperoxidase was carried out in the presence of glucose and glucose oxidase . A major polypeptide (175 kDa) was radioiodinated by this procedure . Iodination of the 175-kDa polypeptide appeared to be receptor-mediated, since it was blocked by the presence of yeast mannan . Specific iodination was absent from receptor-negative cells . To demonstrate that the 175-kDa species is a ligand-binding protein, cells were iodinated by the standard lactoperoxidase method . Washed cells were then allowed to bind mannose-BSA . Receptor-ligand complexes, prepared by detergent extraction, were passed over anti-BSA IgG affinity columns . Mannose, but not mannose 6-phosphate or galactose, eluted a radioactive protein from the column that migrated with an apparent molecular mass of 175 kDa on NaDodSO4/PAGE . Detergent extracts of crude membranes prepared from macrophage-enriched whole rabbit lung were adsorbed to mannose-Sepharose; the fraction obtained by elution with mannose contained two protein components of 175 and 55 kDa . Subsequent chromatography on N-acetylglucosamine-agarose yielded a single protein of 175 kDa . The 175-kDa polypeptide was shown to bind 125I-labeled mannose-BSA in a precipitation assay . This binding could be blocked with mannan or mannose-BSA . The results indicate that the cell-surface mannose receptor is a 175-kDa protein. Proc Natl Acad Sci U S A, 1986 Apr, 83(7), 2007 - 11 Molecular cloning of cDNA for the nuclear ribonucleoprotein particle C proteins: a conserved gene family; Nakagawa TY et al.; The C proteins, C1 and C2, are major constituents of the heterogeneous nuclear RNA (hnRNA) ribonucleoprotein (hnRNP) complex in vertebrates . C1 and C2 are antigenically related phosphoproteins that are in contact with hnRNA in intact cells and bind to RNA tightly in vitro . A cDNA clone for the C proteins was isolated by immunological screening of a human lambda gt11 expression vector cDNA library with monoclonal antibodies . The lacZ-cDNA fusion protein is recognized by two different anti-C protein monoclonal antibodies . HeLa cell mRNA that was hybrid-selected with the cDNA clone (1.1 kilobases long) was translated in vitro and yielded both the C1 and C2 proteins (41 and 43 kDa, respectively) . RNA blot analysis showed strong hybridization to two polyadenylylated transcripts, of about 1.4 kb and 1.9 kb, in human cells . Genomic DNA blot analysis showed multiple hybridizing restriction fragments in human and mouse, and homologous DNA sequences are found across eukaryotes from human to yeast . These findings suggest that the sequences encoding the hnRNP C proteins are members of a conserved gene family and they open the way for detailed molecular and genetic studies of these proteins. Physiologie, 1986 Apr-Jun, 23(2), 139 - 43 Symmetrical-asymmetrical codons and hydrophobic-hydrophilic amino acids; Portelli C et al.; The symmetrical codons present in the first and third positions two purine (P) or two pyrimidine (p) bases (e.g . PNP or pNp), while the asymmetrical codons present in the first and third positions a purine and a pyrimidine base (e.g . PNp or pNP) . The percentages of symmetrical and asymmetrical codons specifying hydrophobic and hydrophilic amino acids are similar in the genes of viruses and vertebrates, which utilise the "universal" genetic code, but they are different for the genes of human mitochondria and yeast mitochondria, which utilize two specific genetic codes. J Biomol Struct Dyn, 1986 Apr, 3(5), 843 - 57 On loop folding in nucleic acid hairpin-type structures; Haasnoot CA et al.; In a series of studies, combining NMR, optical melting and T-jump experiments, it was found that DNA hairpins display a maximum stability when the loop part of the molecule comprises four or five nucleotide residues . This is in contrast with the current notion based on RNA hairpin studies, from which it had been established that a maximum hairpin stability is obtained for six or seven residues in the loop . Here we present a structural model to rationalize these observations . This model is based on the notion that to a major extent base stacking interactions determine the stability of nucleic acid conformations . The model predicts that loop folding in RNA is characterized by an extension of the base stacking at the 5'-side of the double helix by five or six bases; the remaining gap can then easily be closed by two nucleotides . Conversely, loop folding in DNA is characterized by extending base stacking at the 3'-side of the double helical stem by two or three residues; again bridging of the remaining gap can then be achieved by one or two nucleotides . As an example of loop folding in RNA the anticodon loop of yeast tRNAPhe is discussed . For the DNA hairpin formed by d(ATCCTAT4TAGGAT) it is shown that the loop structure obtained from molecular mechanics calculations obeys the above worded loop folding principles. J Biol Chem, 1986 Mar 25, 261(9), 4126 - 33 Affinity labeling of nucleotide-binding sites on kinases and dehydrogenases by pyridoxal 5'-diphospho-5'-adenosine; Tamura JK et al.; A new adenine nucleotide analog, {3H}pyridoxal 5'-diphospho-5'-adenosine (PLP-AMP), has been synthesized . The effectiveness of PLP-AMP as an affinity probe has been tested using a number of nucleotide-binding enzymes . In comparison to reaction with pyridoxal 5'-phosphate, PLP-AMP binds more tightly and exhibits greater specificity of labeling for most enzymes tested . PLP-AMP is a very potent inhibitor of yeast alcohol dehydrogenase and rabbit muscle pyruvate kinase, with complete inhibition obtained upon incorporation of 1 mol of reagent/mol of catalytic subunit . The reagent is also a potent inhibitor of yeast hexokinase and phosphoglycerate kinase . When modified in the absence of substrates, these enzymes require 2 mol of reagent/mol of active site for complete inhibition . However, when modified in the presence of sugar substrates, this stoichiometry decreases to 1.1 for the hexokinase-glucose complex and 1.4 for the phosphoglycerate kinase . 3-phosphoglycerate complex . The most potent inhibition by PLP-AMP was observed with rabbit muscle adenylate kinase . Half-maximal inhibition was obtained at a concentration of approximately 1 microM . In contrast to these examples, PLP-AMP, as well as pyridoxal 5'-phosphate, fails to act as a potent or specific inhibitor of beef heart mitochondrial F1-ATP-ase . The high specificity of labeling and the ability of nucleotide substrates to decrease the rate of inactivation of the kinases and dehydrogenase are consistent with the modification of active site residues . The complete reversibility of both modification and inactivation in the absence of reduction by NaBH4 and the absorption spectra of modified enzymes prior to and following reduction indicate reaction with lysyl residues . We conclude that PLP-AMP holds considerable promise as an affinity label for exploring the structure and mechanism of nucleotide-binding enzymes. Biochem J, 1986 Mar 15, 234(3), 717 - 26 Analysis of Hill slopes predicted by the four-ligand exponential model for a regulatory enzyme; Ainsworth S; The four-ligand exponential model for a regulatory enzyme is described as it is applied to kinetic studies of yeast pyruvate kinase in which the concentrations of four ligands are systematically varied . The Hill slopes predicted by this model are calculated for the two situations in which the fourth ligand is either a substrate or an effector . It is shown that the individual terms that make up the expression for the Hill slope assist the interpretation of the observed behaviour in terms of the constants employed by the model. Nucleic Acids Res, 1986 Mar 11, 14(5), 2035 - 44 Conservation of the cellular gene encoding the scrapie prion protein; Westaway D et al.; The major protein, PrP 27-30, in purified preparations of hamster scrapie prions is encoded within the genome of the experimental host . DNA sequences related to a PrP cDNA clone can be detected in a wide variety of organisms under relatively stringent conditions where the only signal generated by hamster or mouse DNA corresponds to the PrP gene . Three hosts for scrapie, goat, sheep and rat gave strong hybridization signals . In addition, three invertebrate DNAs reacted with the PrP probe, in the order nematode-Drosophila much greater than yeast . Thus, the sequences detected in goat, sheep, rat, nematode, Drosophila and possibly yeast DNA may arise from authentic PrP genes . This evolutionary conservation is consistent with the notion that PrP proteins participate in essential cellular processes. Biochim Biophys Acta, 1986 Mar 7, 870(1), 160 - 8 Inhibition of mammalian glyoxalase I (lactoylglutathione lyase) by N-acylated S-blocked glutathione derivatives as a probe for the role of the N-site of glutathione in glyoxalase I mechanism; Al-Timari A et al.; A series of twelve S-blocked and N,S-blocked glutathione derivatives has been studied as inhibitors of glyoxalase I {R)-S-lactoylglutathione methylglyoxal-lyase (isomerising), EC 4.4.1.5) from human erythrocytes . A number of new N,S-blocked glutathiones have been synthesised . Inhibition at pH 7.0, 25 degrees C was linear-competitive in all cases and the Ki values were interpreted in terms of the absence of a specific binding interaction for the N-site of the inhibitor and the absence of coupling between binding processes at N- and S-sites (the regions around the NH2 and HS groups, respectively, of GSH analogues bound to enzyme) . These observations are in strong contrast to previous results with the yeast enzyme . Some Ki values were measured for yeast glyoxalase I . A special binding interaction of the phenyl groups with enzyme from both species was found for glutathione derivatives with N-acyl groups of structure -NH X CO X X X Y X Ph but not for -NH X COPh, where X and Y were variously -CH2-, -NH- and -O- . Studies were made of the range of stability of human erythrocyte glyoxalase I to pH . The pH profiles for the Ki values of S-p-bromobenzyl)glutathione and N-acetyl-S-(p-bromobenzyl)glutathione indicated no pH dependence for the latter and little, if any, for the former inhibitor . The mean Ki over the pH range 5-8.5 for S-(p-bromobenzyl)glutathione was 1.21 +/- 0.37 microM and for N-acetyl-S-(p-bromobenzyl)glutathione in the same pH range, Ki decreased from 1.45 +/- 0.26 microM to 0.88 +/- 0.11 M. FEBS Lett, 1986 Mar 3, 197(1-2), 134 - 8 Adenylate cyclase activity of NIH 3T3 cells morphologically transformed by ras genes; Levitzki A et al.; The observed homology between G-proteins which regulate adenylate cyclase and ras proteins and the suggested role of ras in the regulation of adenylate cyclase in yeast prompted us to examine the regulation of adenylate cyclase in three cell lines: (i) NIH 3T3 cells, (ii) NIH 3T3 cells transformed by high levels of the normal rasH gene product and (iii) NIH 3T3 cells transformed by a mutated rasH gene product . We found that the regulation of adenylate cyclase by G-proteins is identical in the three cell lines, although the response of the transformed NIH 3T3 cells to agonists is strongly attenuated . Our data suggest that mammalian ras products do not interact directly with adenylate cyclase, although their increased expression may indirectly inhibit the interaction of adenylate cyclase stimulatory receptors with G-proteins. Acta Physiol Scand, 1986 Mar, 126(3), 413 - 7 Some observations made by intracellular recordings in a primary astrocyte culture and a glioblastoma '138 MG'; Nilsson A et al.; Intracellular recordings were performed in a primary astrocyte culture from rat brain and in a human glioblastoma cell line, 138 MG . The technique proved insufficient to verify the heterogeneous composition of the primary astrocyte culture, since this study shows most cells present in the culture to have similar resting membrane potential, membrane impedance, membrane potential/impedance relationship and K+-sensitivity . With the exception of macrophages, identified by their response to externally applied yeast particles, the results do not allow the identification of different cells that are known to be present . The membrane potential of the primary astrocyte was -68 +/- 14 mV, and the membrane potential of the 138 MG cells -37 +/- 15 mV . The membrane potential of cells in the primary culture have a K+-sensitivity resembling that of astrocytes in situ, whereas the K+-sensitivity of 138 MG more resemble that of a dedifferentiated cell . A reduction of 0.95 mm Ca2+ to o mM depolarizes the astrocyte with 9.6 mV and hyperpolarizes the glioma cell 2.6 mV. Br J Nutr, 1986 Mar, 55(2), 219 - 25 Nutritional availability to rats of selenium in four seafoods: crab (Callinectes sapidus), oyster (Crassostrea virginica), shrimp (Penaeus duorarum) and Baltic herring (Clupea harengus); Mutanen M et al.; 1 . The present study was conducted to determine the biological availability to rats of the selenium in four high-Se seafoods: crab (Callinectes sapidus), oyster (Crassostrea virginica), shrimp (Penaeus duorarum) and Baltic herring (Clupea harengus) . 2 . Weanling male rats were fed on a Se-deficient Torula yeast diet for 4 weeks followed by either continued depletion or repletion for 4 weeks with 0.05, 0.1 or 0.2 microgram Se as selenite/g, or 0.1 or 0.2 microgram Se as freeze-dried cooked test food/g . Plasma and liver Se levels or glutathione peroxidase (EC 1.11.1.9; GSH-Px) activities were used as indicators of body Se status . 3 . Except for oysters, the biological availability of Se in all these seafoods was close to that of selenite (selenite 100%) when the criterion used was either plasma Se level or plasma GSH-Px activity . 4 . By the criterion of increased liver Se level of restored hepatic GSH-Px activity, only herring-Se had a biological availability comparable to that of selenite-Se under all conditions tested, whereas crab-Se and oyster-Se were distinctly inferior in this regard . 5 . Increasing the amount of crab-Se, oyster-Se or shrimp-Se supplied in the diet from 0.1 to 0.2 microgram/g changed the apparent availability (%) of Se for hepatic GSH-Px restoration from 38 to 78, 22 to 53 and 57 to 90 respectively . 6 . The present study demonstrates that the availability of Se in certain foods is a function of the criterion chosen, the level of Se supplied in the diet, and possibly other unknown interacting dietary factors. Pharmacol Res Commun, 1986 Mar, 18(3), 241 - 56 Pharmacological activity of FPP028 (2-phenylpyrazolo-4-ethyl-4,7-dihydro {1,5a}pyrimidin-7-one) a new non-steroid anti-inflammatory agent; Pirisino R et al.; The activity of 2-phenylpyrazolo-4-ethyl-4,7-dihydro {1,5a}pyrimidin-7-one (FPP028), a non-acidic, analgesic, antipyretic, and anti-inflammatory compound, was investigated in a number of pharmacological tests performed in rats . The anti-inflammatory properties of FPP028 were evaluated through the carrageenan induced paw edema and the cotton pellet induced granuloma and compared with the activity of indomethacin, phenylbutazone, and isoxicam; as a result, the activity of FPP028 was shown to be similar to that of the latter compounds . To assess the analgesic properties of FPP028 in comparison with indomethacin and phenylbutazone, the Randall and Sellitto and the mouse-writhing tests were used; in both tests, FPP028 demonstrated a significant analgesic activity . FPP028 was shown to possess antipyretic properties in the test of yeast-induced pyrexia . The gastro-erosive activity of phenylbutazone and FPP028 was studied in restraint-stressed rats; in such test the ulcerogenic activity of phenylbutazone appeared to be dose-related; conversely, FPP028 demonstrated a gastro-protective effect since the number of gastric lesions induced either by stress or phenylbutazone treatment was decreased bu FPP028 . Our data show that FPP028 is endowed with most of the pharmacological properties of the classic antiinflammatory drugs . Further studies are however needed to more fully elucidate its mechanism of action because our in-vivo data indicate that FPP028 is not an inhibitor of prostaglandin biosynthesis. Lab Invest, 1986 Mar, 54(3), 336 - 44 Cell differentiation and cell cycle effects on human promyelocytic leukemia cells induced by 12-O-tetradecanoylphorbol-13-acetate; Yun K et al.; As has been reported, doses of 12-O-tetradecanoylphorbol-13-acetate (TPA) as small as 1 to 100 ng/ml induced human promyelocytic leukemia HL-60 cells to differentiate terminally into macrophage-like cells rather than toward cells of the granulocytic series . This differentiation was accompanied by the appearance of monocyte/macrophage markers and by the disappearance of myeloid markers from the view point of enzyme cytochemistry . Contrasted to untreated HL-60 cells, TPA-treated cells increased in cell size and showed increased phagocytotic activities against opsonized sheep blood red cells and activated yeast . Nitroblue tetrazolium-positive cells increased rapidly after TPA exposure . The alterations of the cell cycle traverse of HL-60 cells by TPA were analyzed by {3H}thymidine autoradiography, flow microfluorimetry, and mitotic cell counting . TPA sequentially caused (a) inhibition of cells to move from G1 to S near G1/S boundary in G1; (b) temporary inhibition in G2; (c) growth arrest of most cells in G1 within 2 to 3 days after TPA exposure. Semin Respir Infect, 1986 Mar, 1(1), 22 - 8 Immunodiagnosis of blastomycosis; Turner S et al.; The diagnosis of blastomycosis has long been a challenge for the clinician . Primarily a pulmonary disease, blastomycosis is difficult to differentiate from other respiratory infections by clinical symptoms alone . Substantial improvement in the diagnosis of blastomycosis can be attributed to the availability of the purified A antigen of Blastomyces dermatitidis and its homologous antibody and the incorporation of these reagents into diagnostic tests . Reliable procedures for accurately and rapidly immunodiagnosing blastomycosis are available . These methods comprise enzyme immunoassay and immunodiffusion tests for detecting diagnostic serum antibody by B dermatitidis, the exoantigen test for identifying mycelial-form cultures of the etiologic agent, and the fluorescent antibody technique for detecting and identifying yeast-form cells in culture or in tissue . These tests, used alone or in combination, can in many cases provide an early and rapid definitive diagnosis of blastomycosis. Neuropharmacology, 1986 Mar, 25(3), 309 - 13 Evidence against adenosine 3',5'-monophosphate as a mediator of fever in the brain; Dascombe MJ; The aim of this study was to test the hypothesis that increased concentrations of adenosine 3',5'-monophosphate (cyclic AMP) in the pyrogen-sensitive preoptic/anterior hypothalamic region (PO/AH) mediate fever . Micro-injection of N6-2'-O-dibutyryl adenosine 3',5'-monophosphate (db cyclic AMP) into the preoptic/anterior hypothalamic region in rats produced a dose-dependent fall in body temperature which is inconsistent with the proposal that the nucleotide mediates fever . Hyperthermia was observed in some rats in response to large doses of db cyclic AMP, but this response was associated with convulsions . Endogenous concentrations of cyclic AMP in the preoptic/anterior hypothalamic region, as well as in the cerebral cortex, liver, spleen, thymus, white fat and plasma were unaffected by the febrile response to the subcutaneous injection of yeast in rats . A rise in levels of cyclic AMP was observed in the skeletal muscle of rats treated with yeast . The data presented do not indicate that cyclic AMP is involved in the neuronal events mediating fever in the rat. Am Rev Respir Dis, 1986 Mar, 133(3), 353 - 6 A genetically engineered, mutant human alpha-1-proteinase inhibitor is more resistant than the normal inhibitor to oxidative inactivation by chemicals, enzymes, cells, and cigarette smoke; Janoff A et al.; Alpha-1-proteinase inhibitors (alpha 1PI) containing methionine (Met-358) or valine (Met----Val-358) at the reactive center were synthesized in and purified to homogeneity from recombinant yeast . The pure proteins were exposed to 1 of 4 different oxidizing systems: N-chlorosuccinimide (chemical oxidation), myeloperoxidase plus peroxide and halide (enzymatic oxidation), activated neutrophils (cellular oxidation), or gas-phase cigarette smoke . The effect of these treatments on the leukocyte elastase inhibitory function of both proteins was then assessed . After brief exposures, substantial inactivation of the normal inhibitor occurred, whereas the mutant inhibitor remained fully active . More prolonged exposures led to complete inactivation of the normal protein and partial inactivation of the mutant inhibitor . These results suggest that the reactive center methionyl residue in alpha 1PI is more rapidly affected by oxidants than are other oxidizable residues in the inhibitor; however, Met-358 is not the only residue in alpha 1PI whose modification can lead to the inactivation of the elastase inhibitory capacity of this protein. Proc Natl Acad Sci U S A, 1986 Mar, 83(5), 1330 - 3 Direct measurements of intramolecular electron transfer rates between cytochrome c and cytochrome c peroxidase: effects of exothermicity and primary sequence on rate; Cheung E et al.; Rapid mixing of ferrocytochrome c peroxidase {cyt c peroxidase(II)} and ferricytochrome c {cyt c(III)} results in the reduction of cyt c(III) by cyt c peroxidase(II) . In 10 mM phosphate, pH 7.0, the rate of decay of cyt c peroxidase(II) and the rate of accumulation of cyt c(II) give equal first-order rate constants: k = 0.23 +/- 0.02 s-1 . Equivalent results are obtained by pulse radiolysis using isopropanol radical as the reducing agent . This rate is independent of the initial cyt c(III):cyt c peroxidase(II) ratios . These results are consistent with unimolecular electron transfer occurring within a cyt c(III)-cyt c peroxidase(II) complex . When cyt c is replaced by porphyrin cyt c (iron-free cyt c), a complex still forms with cyt c peroxidase . On radiolysis, using e-aq as the reducing agent, intracomplex electron transfer occurs from the porphyrin cyt c anion radical to cyt c peroxidase(III) with k = 150 s-1 . This large rate increase with increasing delta G degrees suggests that the barrier for intracomplex electron transfer is large . Finally, we have briefly investigated how the cyt c peroxidase(II)----cyt c(III) rate depends on the primary structure of cyt c(III) . We find the reactivity order to be as follows: yeast (k = 3.4 s-1) greater than horse (k = 0.3 s-1) greater than tuna (k = 0.2 s-1) . These results mirror a report {Ho, P . S., Sutoris, C., Liang, N., Margoliash, E . & Hoffman, B . M . (1985) J . Am . Chem . Soc . 107, 1070-1071} on excited state reactions of the cyt c/cyt c peroxidase couple. Cancer Res, 1986 Mar, 46(3), 1388 - 94 Expression of tissue transglutaminase in cultured monocytic leukemia (THP-1) cells during differentiation; Mehta K et al.; Retinoic acid (RA) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) induced differentiation of a human monocytic leukemia cell line, THP-1 . RA- or TPA-treated cells stopped proliferating, became adherent to plastic surfaces, and acquired the ability to phagocytose yeast cells, plain sheep RBCs, and IgG-coated sheep RBCs . The morphological and functional changes, induced by RA or TPA, were associated with a 20-50-fold increase in cellular transglutaminase activity . This increase in enzyme activity was found to be due to the induction of a specific intracellular transglutaminase, tissue transglutaminase . The induction of tissue transglutaminase was a specific response of THP-1 cells to differentiation and was not observed with agents that did not induce their morphological or functional differentiation . Dibutyryl cyclic AMP potentiated the RA-induced expression of tissue transglutaminase . A 15-min exposure to TPA was sufficient to induce differentiation and expression of tissue transglutaminase in THP-1 cells . In contrast, RA required a continuous exposure (48 h) to induce similar changes in morphology or enzyme activity . These results support the view that differentiation of cells of the monocytic lineage is associated with an induction and accumulation of the protein cross-linking enzyme tissue transglutaminase. Eur J Biochem, 1986 Feb 17, 155(1), 1 - 10 Study of the plasma clearance of antibody--ricin-A-chain immunotoxins . Evidence for specific recognition sites on the A chain that mediate rapid clearance of the immunotoxin; Bourrie BJ et al.; In recent years, antibody--ricin-A-chain immunotoxins have been investigated as anti-neoplastic agents . To achieve in vivo therapy it is necessary that the immunotoxin remains in circulation at a sufficiently high level for a sufficiently long time to allow binding to tumor cells to occur . Therefore, examination of the pharmacology of immunotoxins may elucidate the reasons for the poor in vivo tumoricidal effect of immunotoxin described before . In this study the plasma clearance of antibody--ricin-A-chain immunotoxins, after intravenous injection in animals of different species, has been examined . Sensitive and reproducible techniques were developed to monitor the level of immunotoxin and its constituents in the blood . It is shown that immunotoxins are rapidly eliminated from the bloodstream . Neither the properties of the antibody moiety nor the nature of the linkage binding ricin A-chain to antibody account for the disappearance of immunotoxin from the plasma . On the other hand, we found that the rapid clearance of immunotoxin is due to the mannose residues on the ricin A-chain moiety which are specifically recognized by liver cells . When immunotoxin is administrated together with yeast mannan, which enhances the level of active immunotoxin in circulation by inhibition of liver uptake, the anti-cancer efficacy of immunotoxin in vivo is drastically improved. J Biol Chem, 1986 Feb 15, 261(5), 2214 - 21 Glycine decarboxylase multienzyme complex . Purification and partial characterization from pea leaf mitochondria; Walker JL et al.; The P, H, and T proteins of the glycine cleavage system have been purified separately from pea leaf mitochondria and demonstrate molecular weights of 98,000, 15,500, and 45,000, respectively, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis . The molecular weight of P protein by gel filtration was 210,000, indicating that this enzyme has a native homodimer conformation . Reconstitution assays containing purified P, H, and T proteins and yeast lipoamide dehydrogenase catalyze the oxidation of glycine and demonstrate a strict dependence on pyridoxal phosphate, tetrahydrofolate, NAD+, and dithiothreitol . The released CO2, methylamine-H protein intermediate, and methylenetetrahydrofolate are produced in stoichiometric amounts from glycine during the cleavage reaction . H protein acts as co-substrate with glycine during the decarboxylation reaction, demonstrating an apparent Km value of 2.2 microM . P and H protein alone jointly catalyze the glycine carboxyl-14 CO2 exchange reaction in the presence of pyridoxal phosphate and dithiothreitol . L protein of the glycine cleavage system was immunopurified using monoclonal antibodies . Antigenic and molecular weight similarities of the L protein with the lipoamide dehydrogenase component of the pyruvate dehydrogenase complex were shown suggesting the possibility of common isomers of lipoamide dehydrogenase for the two enzyme complexes. J Biol Chem, 1986 Feb 5, 261(4), 1941 - 8 hv1 is an evolutionarily conserved H2A variant that is preferentially associated with active genes; Allis CD et al.; Polyclonal antibodies to the Tetrahymena macronuclear-specific histone variant hv1 cross-react with histone-like molecules from yeast, wheat, and mouse . A novel purification scheme has allowed isolation of sufficient hv1 to enable determination of the sequence of 61 amino-terminal residues as well as 27 additional internal residues . These data clearly demonstrate that hv1 shares a number of conserved sequence elements with the H2A family of histones . Comparison of hv1 with H2A.F (= H2A.Z = M1), another evolutionarily conserved H2A variant whose sequence is known, reveals that they share an unblocked amino-terminal alanine (instead of acetylserine) and a distinctive structure in a "variant box" region that distinguishes them from major H2As . In addition, 10 residues have been identified which are identical (or highly similar) in hv1 and H2A.F, but are different from residues conserved in the major H2As . Therefore, in many ways hv1 resembles chick H2A.F more than the major Tetrahymena H2A . The sites of acetylation of hv1 also differ from those of the major Tetrahymena H2As . In spite of their similarities, hv1 and H2A.Z differ significantly in their amino termini, and antibodies against hv1 do not react with H2A.Z . Interestingly, the nucleolar staining pattern reported with anti-hv1 serum is similar to that reported for an antiserum to another H2A variant, mouse testes-enriched H2A.X . Since both H2A.Z and hv1 appear to be enriched in transcriptionally active chromatin, these results suggest that there may be a number of different, functionally distinct, nonallelic variants in the H2A family of histones and that hv1 is a hybrid H2A variant with properties of both vertebrate H2A.Z and H2A.X. J Med Microbiol, 1986 Feb, 21(1), 7 - 11 Fungicidal activity of murine broncho-alveolar macrophages against Blastomyces dermatitidis; Sugar AM et al.; The fungicidal activity of murine broncho-alveolar macrophages (BAM) against the yeast form of a virulent strain of Blastomyces dermatitidis was studied in the small-volume wells of a Terasaki plate . In a 4-h fungicidal assay, significant killing (16-33%) of the fungus by unstimulated BAM was demonstrated with BAM from normal mice and from mice rendered immune to lethal infection with B . dermatitidis . No significant differences between the activity of BAM from these two sources could be identified . Addition of 10% autologous normal or immune serum did not augment the macrophage fungicidal activity . Simultaneous experiments with peritoneal macrophages (PM) also gave reproducible killing of the yeast form in the wells of the Terasaki plate, but in the larger wells of microtitration plates, PM showed no significant fungicidal activity . On the other hand, BAM had similar fungicidal activity against B . dermatitidis in Terasaki and microtitration-plate wells . The modest fungicidal activity of BAM from immune mice against B . dermatitidis suggests that the resistance of immune mice to respiratory challenge is likely to be based on some augmentation of this first line of defence. J Cell Sci, 1986 Feb, 80, 123 - 40 Calcium ions initiate the selective depolymerization of the pellicular microtubules in bloodstream forms of Trypanosoma brucei; Dolan MT et al.; Calcium ions (100 microM) were found to initiate the selective and complete depolymerization of the pellicular microtubules of Trypanosoma brucei . The Ca2+-dependent release of tubulin was found to occur without the detectable mediation of calmodulin . The released, depolymerized, pellicular tubulin from T . brucei cross-reacted with a monoclonal antibody raised against yeast tubulin . The pellicular tubulin was found to be composed of two alpha isotypes (apparently equal amounts) and one beta isotype . No other proteins were released from the plasma membrane-microtubule complexes during treatment with Ca2+ . The released pellicular tubulin was capable of reassembly into microtubules with normal ultrastructure . The observations reported here suggest that a special process may be required to accommodate the cleavage furrow during cytokinesis . This process would either be the Ca2+-dependent depolymerization of at least two of the cross-linked pellicular microtubules or the detachment of the cross-bridges between two pairs of pellicular microtubules on opposite sides of the cell. J Med Vet Mycol, 1986 Feb, 24(1), 41 - 50 Endemic canine and feline histoplasmosis in El Paso, Texas; Kabli S et al.; Seventeen cases of histoplasmosis involving 2 dogs and 15 cats have occurred in the Upper Rio Grande Valley of El Paso since 1978 . The diagnosis, based on clinical signs and radiographic findings, was confirmed by one or more of the following laboratory procedures: demonstration of intracellular Histoplasma capsulatum yeast cells in tissue, positive serology, or isolation of H . capsulatum from various organs of necropsied animals . H . capsulatum was isolated also from a bat cave and soil in the vicinity of some of the houses where the affected animals had resided . Skin-tests of 97 persons for histoplasmosis indicated a 14% positive prevalance in this locale. Biosci Rep, 1986 Feb, 6(2), 201 - 8 A study of the messenger RNA encoding pyruvate kinase of Neurospora crassa; Devchand M et al.; In Neurospora crassa, there is a single pyruvate kinase (PK) consisting of four identical subunits of approximately 60k daltons . Northern and dot blot hybridization studies, using most of the yeast pyruvate kinase gene as a probe, suggest the presence of two distinct mRNA species for pyruvate kinase, separable on the basis of the length of their polyadenylated tails, by oligo(dT)cellulose chromatography . These messages are present in polysomes, immuno-precipitated by anti-PK antibodies, indicating probable translation in vivo . Fractions containing both messages were translated in vitro in the heterologous systems as well as in a homologous N . crassa lysate, the newly-synthesized PK being detected by immunoadsorption . Protection studies using S1-nuclease suggest no major structural differences in the 5'-untranslated and most of the coding regions of the two messages. J Biol Chem, 1986 Jan 25, 261(3), 1349 - 54 The binding of the chromosomal protein HMG-2a to DNA regions of reduced stabilities; Brown JW et al.; The interaction of immunopurified high mobility group 2a protein (HMG-2a) with DNA was examined by the nitrocellulose filter binding assay . The relative binding activity of HMG-2a for synthetic polynucleotides was: (dI).(dC) greater than (dA-dT).(dA-dT) greater than (dA).(dT) much greater than (dG).(dC) greater than (dG-dC).(dG-dC) . The protein also exhibited a marked preference for (A + T)-rich restriction fragments derived from rat and Drosophila satellites, yeast centromeres, phage lambda, and the ovalbumin gene and its 5' flanking sequences . These preferential DNA interactions occurred at ionic strengths and temperatures within the physiological range which argue for an in vivo role of DNA stability in dictating the genomic distribution of the large Mr HMG proteins. Br Med J (Clin Res Ed), 1986 Jan 18, 292(6514), 159 - 61 Antibody responses to recombinant and plasma derived hepatitis B vaccines; Brown SE et al.; The antibody response to hepatitis B surface antigen (anti-HBs) induced in 25 recipients of a recombinant hepatitis B vaccine derived from yeast was compared with that induced in 25 recipients of a vaccine prepared from hepatitis B surface antigen (HBsAg) derived from plasma . Anti-HBs affinity and specificity were compared using assays of antibody affinity with two different antigens, a complex of the major polypeptide of HBsAg (p25; molecular weight 25 000 daltons) covalently linked to its glycosylated form (gp30) prepared from native purified HBsAg, and a cyclical synthetic peptide representing amino acid residues 139-147 of the major polypeptide of HBsAg and known to represent a major part of an a determinant . There was no difference in anti-HBs affinity or molar antigen binding sites of the antibody measured with either antigen between the two groups . All subjects in both groups produced antibody that bound to the gp30/p25 complex antigen, whereas 22 of the recipients of the plasma derived vaccine compared with 24 of those receiving the yeast derived vaccine produced antibodies that bound to the cyclical synthetic peptide 139-147 . These results support the finding of similar levels of anti-HBs, measured by commercial solid phase radioimmunoassay, in the two vaccine groups after three doses of vaccine . These results show no significant difference in the quantity, quality, or specificity of the anti-HBs response induced by the recombinant hepatitis B vaccine and the plasma derived hepatitis B vaccine. J Biol Chem, 1986 Jan 15, 261(2), 869 - 73 Nuclear genes for cytochrome c oxidase subunits of Neurospora crassa . Isolation and characterization of cDNA clones for subunits IV, V, VI, and possibly VII; Sachs MS et al.; We obtained cDNA clones for cytochrome oxidase subunits IV, V, VI, and possibly VII by constructing a lambda gt11 library of Neurospora crassa cDNA and probing it with antiserum directed against Neurospora cytochrome oxidase holoenzyme . Positive clones were further characterized with antisera directed against individual cytochrome oxidase subunits and subsequently by DNA sequencing . The clones for subunits IV and V encode proteins with regions matching the known N-terminal amino acid sequences of purified Neurospora cytochrome oxidase subunits IV and V, respectively . The sequences of these clones provide the first evidence that cytochrome oxidase subunits IV and V are made as precursors with N-terminal extensions in Neurospora . The N-terminal extensions encoded by these clones share homology, and are rich in arginine, as are signal sequences of other mitochondrially destined proteins . The subunit VI clone codes for the carboxyl terminus of a protein homologous to the carboxy termini of yeast cytochrome oxidase subunit VI and bovine cytochrome oxidase subunit Va . The subunit VII clone contains an open reading frame for a 47-residue protein, the expected size for subunit VII . However, the protein coded by this clone has an unusual amino acid composition . Whether this clone represents an authentic cytochrome oxidase subunit is not established. Drug Nutr Interact, 1986, 4(3), 309 - 19 Selenium deficiency and detoxication functions in the rat: short-term effects of cadmium; Olsson U; Weanling rats were fed a Torula yeast-based selenium-deficient diet with or without supplementation of sodium selenite (0.2 ppm selenium) in the drinking water . After 5-6 weeks on the diet regimens, the liver glutathione peroxidase activity of the selenium-deficient groups had decreased to about 1% of the supplemented groups, and the rats were then used in experiments . Cadmium-induced effects on the drug-metabolizing system of the liver were measured as the microsomal capacity to perform N- and C-oxygenation of N, N-dimethylaniline . Cadmium in vitro caused a decrease of the cytochrome P-450-dependent C-oxygenation . This effect tended to be more prominent in the selenium-deficient groups . On the other hand, N-oxygenation was increased when cadmium was added in vitro, and no significant difference was found between selenium-deficient and -supplemented groups . However, as was found for the capacity to perform C-oxygenation, there was a tendency for lower N-oxygenation in the selenium-deficient rat . Lipid peroxidation, measured as thiobarbituric acid reactive substances in liver homogenates, was higher in selenium-deficient groups after in vivo treatment or in vitro addition of cadmium, and preincubation or phenobarbital induction enhanced this selenium-dependent difference . Although, the selenium-deficient rat seems more susceptible to cadmium-induced disturbances, 5-6 weeks of selenium deficiency was not enough to cause prominent impairment on the drug-metabolizing system as measured here and with the doses used in the present study. Biokhimiia, 1986 Jan, 51(1), 59 - 64 {Characteristics of thiamine thiazolone diphosphate-induced inhibition of a pyruvate dehydrogenase complex in vitro and in intact mitochondria}; Iakovleva GM et al.; Thiamine thiazolone diphosphate (TTPP) was capable of penetrating through the mitochondrial membrane and of inhibiting the pyruvate dehydrogenase complex (PDC) in intact mitochondria . TTPP depressed the activity of mammalian PDC in a mixed manner (Ki = 5.10(-8) M) and yeast pyruvate decarboxylase (Ki = 5.10(-6) M) via a competitive mechanism with respect to thiamine diphosphate . It was shown that decarboxylation of pyruvate in intact and disrupted mitochondria of rat liver and brain is less inhibited by TTPP than the overall activity of PDC determined by the formation of acetyl-CoA . It was assumed that TTPP as a transition state analog participates only in oxidative reactions (but not in simple decarboxylation of pyruvate). Anal Biochem, 1986 Jan, 152(1), 160 - 6 High-performance liquid chromatography of aldehydes and acids formed in monoamine oxidase-catalyzed reactions; Yu PH et al.; A rapid, sensitive, and specific method for the determination of monoamine oxidase (MAO) activities toward different substrates is described . The assay is based on high-performance liquid chromatographic (HPLC) separation and electrochemical detection of the aldehyde or acid products . The aldehyde metabolic intermediates were observed to be quite stable in 0.1 N perchloric acid containing antioxidant and EDTA, and therefore can be used to measure the MAO activity of washed mitochondrial membrane and partially purified or purified MAO . Incomplete conversion of aldehyde to acid was observed when the amine substrates were incubated with the crude enzyme preparations . These aldehydes can be converted to corresponding acids by addition of yeast aldehyde dehydrogenase and beta-NAD and the acid can also be measured by HPLC-electrochemical detection . A deuterium isotope effect in the oxidation of p-{alpha,alpha-2H2}tyramine and {alpha,alpha-2H2}serotonin has been demonstrated by this method. Arch Biochem Biophys, 1986 Jan, 244(1), 211 - 7 Physiological requirement for biosynthesis of multiple 24 beta-methyl sterols in Gibberella fujikuroi; Nes WD et al.; Studies with Gibberella fujikuroi have been designed to examine the relationship between the biosynthesis and function of fungal sterols . Evidence was obtained through appropriate feeding and trapping experiments for the existence of multiple end products which are produced by separate routes in the later stages of sterol biosynthesis . The three end products, ergosterol (24 beta-methylcholesta-5,7,22E-trien-3 beta-ol), brassicasterol (24 beta-methylcholesta-5,22E-dien-3 beta-ol), and 22(23)-dihydrobrassicasterol (24 beta-methyl-cholesterol), were found to be non-interconvertible during logarithmic phase growth; thus the metabolic route delta 5,7,22-24 beta-CH3----delta 5,22-24 beta-CH3----delta 5-24 beta-CH3 was ruled out . Ergosterol can be further metabolized, viz., to 24 beta-methylcholesta-5,7,9(11),22-tetraen-3 beta-ol, but only as the culture enters into the stationary phase . In the presence of growth inhibitory concentrations of 2,3-iminosqualene, a partial reversal of growth cessation was obtained when all three sterols were concurrently supplied to the medium . Since neither ergosterol nor the other two sterols added individually to the medium was able to overcome the inhibitor's deleterious effect, ergosterol cannot play a dual architectural role (bulk and regulatory) in this fungus as it apparently can do in other fungal systems, i.e., yeast . For G . fujikuroi each sterol end product appears to possess a unique physiological role . Mycelial growth requires more than simply ergosterol. Toxicol Appl Pharmacol, 1986 Jan, 82(1), 140 - 50 Toxicity of cadmium chloride in vitro: indices of cytotoxicity with the pulmonary alveolar macrophage; Coin PG et al.; Pulmonary alveolar macrophages were isolated from adult, male New Zealand white rabbits by bronchial lavage and exposed to cadmium chloride in vitro . The observed cell sensitivity to this metal was highly dependent upon the incubation conditions used as well as the cytotoxic index selected . An LC50 value, as measured by dye exclusion (erythrosin B), was determined to be 390 microM when these cells were exposed to cadmium in Ham's F12 culture medium for 8 hr at 35 degrees C . The presence of fetal calf serum in the medium (10%; v/v) enhanced this toxicity slightly, LC50 = 235 microM, as did raising the incubation temperature to 37 degrees C, LC50 = 201 microM . No effect on cadmium toxicity was observed when the culture medium was made deficient in Cu, Zn, and Fe, nor was there any effect observed when Hepes buffer was substituted for the bicarbonate/carbon dioxide buffering system . Measurements of cadmium-109 uptake by pulmonary alveolar macrophages were consistent with and could explain, at least in part, the above observations of cytotoxicity . In the standard culture system (an 8-hr exposure period at 35 degrees C in Ham's F12 culture medium plus serum), the appearance in the culture medium of two lysosomal enzyme activities, acid phosphatase and cathepsin D, paralleled cell death . In addition, an EC50 value of 102 microM was found for cadmium when cell respiration (O2 uptake) was measured; an EC50 value of 31 microM was found for cadmium when cell function (engulfment of killed yeast particles) was followed; and scanning electron microscopic studies showed cell membrane changes (loss of fine structure and blebbing) at cadmium concentrations as low as 30 microM . These findings suggest that loss of cell function and/or changes in cell morphology are more sensitive measurements of macrophage exposure to cadmium than is either cell death, lysosomal enzyme release, or cell respiration. Infect Immun, 1986 Jan, 51(1), 6 - 9 Activation of the alternative complement pathway by Sporothrix schenckii; Scott EN et al.; We studied the activation of complement by Sporothrix schenckii yeast cells . Total complement activity, and the effect of various activators on this activity, were assayed on aliquots of fresh nonimmune human serum with and without prior treatment with chelators . Both total hemolytic complement and C3 were consumed (activated) in serum chelated with magnesium ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, which blocks the classical pathway but leaves the alternative pathway intact . Further, C3 was consumed, but C4 (exclusively a component of the classical pathway) was preserved, in nonchelated serum after challenge by S . schenckii yeast cells . Absorption of serum with S . schenckii yeast cells to deplete antibodies did not alter these results . Furthermore, immunofluorescence studies demonstrated that C3, but not immunoglobulin G, was deposited on yeast cells during incubation with nonimmune serum . These data indicate that S . schenckii yeast cells activate the alternative complement pathway in vitro independently of antibody . These data do not define a role for the alternative pathway in in vivo host defenses against infection with this organism but provide a foundation for studies to evaluate such a role. J Hepatol, 1986, 3(2), 190 - 5 Immunogenicity of recombinant hepatitis B vaccine in dialysis patients; Jilg W et al.; Eighty-eight dialysis patients were vaccinated with recombinant hepatitis B vaccine prepared in yeast . Fourty-nine patients were immunized 3 times (months 0, 1, 6) intragluteally with 40 micrograms hepatitis B surface antigen (HBsAg) per dose . Only 32 of them (65.3%) showed anti-HBs concentrations above 10 IU/l with a geometric mean titer (GMT) of 180.7 IU/l after 3 vaccinations, whereas all of the 16 healthy controls, vaccinated 3 times with a 10-micrograms dose of the same vaccine batch, had specific antibodies higher than 10 IU/l (GMT 897.4 IU/l) . Responses of patients were slightly higher than those of dialysis patients vaccinated in an earlier study with plasma-derived vaccine according to the same schedule . Results in 20 patients immunized 6 times intragluteally with 40 micrograms HBsAg/dose in monthly intervals were not better (at month 7, 65% showed anti-HBs concentrations greater than 10 IU/l; GMT = 126.6 IU/l), and 19 patients receiving 6 times 20 micrograms HBsAg monthly showed significantly lower responses (anti-HBs greater than 10 IU/l in 42% of vaccinees, GMT = 89.5 IU/l) . The vaccine was tolerated well; side-effects were slight, and no serious adverse reactions were observed . In conclusion, recombinant hepatitis B vaccine is comparable to plasma-derived vaccine also in the case of dialysis patients; a 6-dose schedule does not seem to have much advantage compared to the conventional 3-dose regimen. Ann Nutr Metab, 1986, 30(4), 233 - 40 Tolerance of low and high dietary selenium throughout the life span of Syrian hamsters; Birt DF et al.; In lifetime studies on the effects of dietary selenium (Se) levels, Syrian hamsters were fed diets containing low (unsupplemented torula yeast), adequate (0.1 ppm Se supplemented from sodium selenite), or excessive (5 ppm Se supplemented from sodium selenite) levels of Se . A commercial ration was fed to separate groups . Male and female hamsters were assigned to each diet, and blood samples were collected at 54 and 79 weeks of age for determination of Se status . Body weights of male hamsters were generally highest in those fed unsupplemented diets and lowest in those fed 5 ppm Se supplements . Female weights did not differ between the three semipurified diets . Erythrocyte and plasma glutathione peroxidase and blood Se values increased with the increments in dietary Se at the 54- and 79-week measurements . Survival was approximately 40-45% lower in hamsters fed the commercial ration than in those fed semipurified diets, but was not altered by the Se level in the semipurified diet. J Neurosci Res, 1986, 16(1), 141 - 56 Neuron-specific enolase: complete structure of rat mRNA, multiple transcriptional start sites, and evidence suggesting post-transcriptional control; Forss-Petter S et al.; The protein encoded by a randomly selected rat brain cDNA clone was identified as neuron-specific enolase (NSE; 4.2.1.11; gamma subunit), based on homology to yeast enolase sequences and the presence of the corresponding 2.5-kb mRNA in rat brain but not in liver, kidney, or muscle tissue . The 2,222-nucleotide NSE and mRNA sequence presented identifies a 68-nucleotide 5' noncoding region, a 1,302-nucleotide open reading frame (corresponding to a primary translation product of 434 amino acids), and 852 noncoding 3' bases . Evolutionary implications based on sequence comparisons to yeast enolase and non-neuronal enolase are discussed . Primer extension analysis indicated the presence of several alternative initiation sites for transcription within 60 nucleotides on the NSE gene . The developmental onset of NSE mRNA expression correlates with the appearance of NSE protein; however, the mRNA reaches adult levels by postnatal week 3, whereas the protein continues to accumulate over the next few months, suggesting regulatory mechanisms in addition to transcriptional control. Mikrobiologiia, 1986 Jan-Feb, 55(1), 120 - 6 {Morphological changes in a chemostat culture of Candida utilis undergoing cyclic changes of pH and pO2}; Lirova SA et al.; The effect of cyclic pH and pO2 changes on the morphology of Candida utilis was studied with time intervals measured in minutes . The pH was varied from 4.5 to 2.6, the pO2 from 70% of the saturation to 0% . The morphology was studied both visually and using the technique of optical-structural computer analysis . The regime with pH changes increased the biomass yield . However, the averaged morphological characteristics showed that the growth was slightly inhibited . Therefore, the yeast population was very heterogeneous, some cells were inhibited while other cells were stimulated, which made the economic coefficient rise . The cells were also inhibited when they were exposed in the conditions of oxygen deficiency for a short period of time . However, the cells could not be inhibited if, at the same time, the pH was extremely low . Changes in the morphology were detected earlier than either the inhibition or stimulation of growth was recorded by measuring the weight of biomass. J Clin Microbiol, 1986 Jan, 23(1), 163 - 9 Guanine is a growth factor for Legionella species; Pine L et al.; Evaluation of previously described chemically defined media for the growth of Legionella pneumophila showed that these media supported poor growth of several strains of L . pneumophila and did not support growth of certain of the Legionella species described later . Growth was stimulated by the dialysate from yeast extract but not by the nondialyzable fraction . Further investigations indicated that the active factors from the yeast extract dialysate were purine or pyrimidine derivatives, and certain known purines and pyrimidines were found to stimulate growth . Of these, guanine universally stimulated growth of all Legionella strains and was a growth requirement for several of the species tested . A balanced, N-(2-acetamido)-2-aminoethanesulfonic acid-buffered, chemically defined medium having guanine or a purine-pyrimidine mix is presented for the general growth of Legionella species. Nucleic Acids Symp Ser, 1986, (17), 167 - 70 Enzymatic synthesis of chimeric tRNAs with unusual numbers of base pairs in the anticodon stem; their structure and properties; Nishikawa K; Chimeric tRNATyr molecules have been constructed by enzymatic procedures in vitro from the 5'-half fragment of T . utilis tRNATyr and the 3'-half fragment of yeast tRNATyr, and vice versa . These chimeric tRNAs contain base-mismatching(s) in the anticodon stem and, therefore, have only 3 or 4 base pairs in the stem . Although the Tm of these chimeras are largely decreased, there seems to be no gross difference between the structure of native and chimeric tRNATyrs at physiological temperatures in the presence of 10 mM MgCl2 . Aminoacylation assays also revealed that the tyrosine-acceptance of the chimeras are fully comparable to that of native tRNATyrs . However, the possibility remains that the properties of the chimeras are considerably different from those of native ones at lower Mg++ concentrations. Acta Paediatr Scand Suppl, 1986, 325, 107 - 11 Experimental research on IGF-1; Skottner A et al.; IGF-1 has been produced by recombinant DNA technology; the host cell is a yeast . Studies in hypophysectomized rats show that IGF-1 has little growth promoting effect unless given by infusion at high doses, and priming with bovine growth hormone did not produce any potentiation . In vitro studies reveal that IGF-1 cross-reacts with the insulin receptor on adipose cells . Immunohistochemical studies have revealed high IGF-1 immunoreactivity in proliferating and differentiating cells in the testes, lymphoid organs and pancreatic islets and particularly in regenerating nerves . Local application of IGF-1 may stimulate regeneration in damaged peripheral nerves . Key words: Curr Genet, 1986, 10(11), 803 - 10 Plasmids of mitochondrial origin in senescent mycelia of Podospora curvicolla; Bockelmann B et al.; Podospora curvicolla displays symptoms of senescence similar but not quite identical to those reported for Podospora anserina . In Podospora curvicolla single hyphae may escape from death leading to a new growth front and consequently to a mode of growth characterized by alternating phases of growth and non-growth . Restriction analyses and hybridization experiments have revealed that the Podospora curvicolla type of senescence is correlated with plasmids originating from amplification of a single distinct region of the mitochondrial DNA containing the 1rRNA gene . In the yeast transformation system sequences of this region may function as autonomously replicating sequences (ARS) . Plasmids (pl1, pl2 and pl3) isolated from different, independently aged mycelia are largely homologous to each other but differ in their excision/junction sites and have different sizes: 10.85 kb (p11), 9.01 kb (pl2) and 10.50 kb (pl3) . The sequence of the most frequently occurring plasmid in ageing strains of Podospora anserina is absent in Podospora curvicolla either as free plasmid DNA or as an integrated part of the mtDNA . Possibly there is a correlation between the absence of this particular sequence in Podospora curvicolla and the type of senescence displayed in this organism. Curr Genet, 1986, 10(10), 755 - 60 Characterization of Phycomyces blakesleeanus mutants temperature-sensitive for heat-shock induced germination; Micol JL et al.; Sixty-nine mutants of the fungus Phycomyces blakesleeanus, temperature-sensitive for heat-shock induced germination, have been characterized . All of them show a low viability at 26 degrees C and normal viability at 16 degrees C . Eleven mutants recover the wild type phenotype if yeast extract is added to the minimal medium; the mutant phenotype of eight of these mutants is also suppressed by the addition of putrescine or other polyamines . The majority of the mutants are affected very early in germination . Spontaneous, heat-shock and acetate induced germination are not equally impaired by some of the mutations, so specific and independent steps seem to be involved in part of the activation mechanism of germination. Curr Genet, 1986, 10(6), 459 - 62 Identification of an autonomously replicating sequence near a histone gene of Physarum polycephalum; Wilhelm ML et al.; Fragments of DNA which function as autonomous replication sequences in yeast were cloned from Physarum polycephalum . The ars activity is located in a 1.2 kbp fragment extending 1.5 kbp to 2.7 kbp upstream of the 5' end of a histone H4 gene . Our recent finding that a replication origin is located at a distance less than 3 kbp of this histone gene suggests that the ars element identified coincides with a specialized replication origin and can be used to direct chromosome replication in Physarum polycephalum. Princess Takamatsu Symp, 1986, 17, 23 - 30 Two new retroviral onc genes, sea and jun; Bos TJ et al.; Avian leukemia virus S13 induces erythroblastosis, granulocytic leukemia, fibrosarcoma, anemia, and endothelial neoplasia . It transforms chick embryo fibroblasts and primitive erythroid cells in culture and is defective in replication . Its onc gene, sea, is expressed as transformation specific env-sea fusion glycoprotein of 155 kDa . Gp155 is proteolytically processed into gp85env and gp70env-sea . The latter shows tyrosine specific protein kinase activity . Avian sarcoma virus 17 induces fibrosarcoma and transforms chick embryo fibroblasts in culture . Its cell derived onc gene, jun, is not related to known onc genes and appears to be expressed as a gag-jun fusion protein of 55 kDa . The amino acid sequence of jun shows homology in its C-terminal region to the C-terminal DNA binding region of the yeast regulatory protein GCN4, suggesting that the jun protein may bind to DNA. Curr Genet, 1986, 10(10), 767 - 75 Behaviour of recombinant plasmids in Aspergillus nidulans: structure and stability; Barnes DE et al.; A pyrG- Aspergillus strain was transformed with plasmid pDJB-1, derived from pBR325 by insertion of the Neurospora crassa pyr4 gene (orotidine 5'-phosphate carboxylase), giving mitotically unstable transformants . Aspergillus DNA which acted as an "autonomously replicating sequence" (ARS) in yeast was inserted into pDJB-1 and the resulting construct, pDJB12.1, gave mitotically stable transformants when introduced into Aspergillus . Transformants obtained with pDJB-1 and pDJB12.1 gave few pyr- progeny in crosses to a pyrG+ strain . Southern hybridisation analysis of pyr+ transformants obtained with pDJB-1 revealed restriction fragments expected for integrated plasmid but transformants obtained with pDJB12-1 showed only bands derived from free plasmid . pDJB-1 and derivatives of pDJB12.1 could be recovered from transformants . These derivatives could not be explained by straightforward excision of integrated pDJB12.1 sequences but could result from recombination between plasmid molecules . Hybridisation of undigested transformant DNAs showed that the transforming DNA was present in a high molecular weight form . These results suggest: (1) pDJB12.1 derivatives and possibly pDJB-1 can replicate autonomously in Aspergillus; (2) A . nidulans DNA acting as an ARS in yeast enhances replication and/or segregation of transforming plasmids in Aspergillus; and (3) recombinant plasmids may undergo rearrangements when introduced into Aspergillus. Acta Paediatr Scand Suppl, 1986, 325, 85 - 9 Current research on recombinant human growth hormone and the related growth factors, IGF-1 and GRF; Fryklund L; A brief introduction is provided to the physiological actions of somatostatin, somatomedins and growth hormone releasing factor (GRF) in relation to human growth hormone (hGH) . The development of recombinant DNA techniques allowed the biosynthesis of somatrem (methionyl hGH), and as the methods were refined, authentic recombinant hGH (methionyl-free) has been produced . rhGH is currently undergoing clinical trials in several countries . Recombinant IGF-1 has also been developed by similar methods, utilizing a yeast as the host cell . In contrast, GRF is too small to be biosynthesized, but can be produced by classical peptide synthesis . Only the N-terminal sequence is required for biological activity, and may be 29, 40 or 44 residues long . Research into the biological effects of both IGF-1 and GRF is underway. Immunol Res, 1986, 5(2), 129 - 38 Phagocytosis of unopsonized zymosan particles by trypsin-sensitive and beta-glucan-inhibitable receptors on bone marrow-derived murine macrophages; Kadish JL et al.; Murine bone marrow cells, plated at 4 X 10(4) cells/well and cultured in 50% fibroblast CM, yielded pure populations of large, individual, adherent cells that were phagocytic and morphologically indistinguishable from macrophages . Adherent macrophages appeared in small numbers with 24 h of culture, increased to maximal cell numbers within 10 days of culture, and remained at these cell densities for at least 11 weeks in culture . The capacities of adherent macrophages to ingest unopsonized zymosan particles and EsIgG, at inputs of 1.25 X 10(7) targets, were expressed by 7 and 40% of the cells derived from 24-hour cultures, respectively, were increased at nearly identical rates to comparable maximal levels within 10-14 days of culture and were exhibited by essentially all adherent cells derived from 2-11-week cultures . The percentage of adherent macrophages from twelve 3-6-week cultures ingesting greater than or equal to 1, greater than or equal to 6 and greater than or equal to 10 zymosan particles was 89 +/- 5, 47 +/- 11 and 14 +/- 9% (mean +/- SD, n = 12), respectively, and the percentage ingesting greater than or equal to 1, greater than or equal 6 and greater than or equal to 10 EsIgG was 86 +/- 5, 49 +/- 10 and 14 +/- 8%, respectively . Incubation of adherent macrophages with mannan-free ss-glucan particles at inputs of 5 X 10(5)-5 X 10(7)/ml initiated a phagocytic response comparable to that obtained with the same doses of zymosan particles which contained mannan and beta-glucan . Preincubation of adherent macrophages with 100 micrograms/ml of a fully soluble beta-glucan, laminarin, and solubilized barley beta-glucan reduced subsequent macrophage phagocytosis of greater than or equal to 6 zymosan particles by 53 and 40%, respectively . In contrast, yeast alpha-mannan was less than 1% as active, and 10 mg/ml reduced the number of adherent macrophages ingesting greater than or equal to 1 zymosan particles by 64% . At concentrations as high as 2 mg/ml, laminarin and barley beta-glucan had no effect on Fc receptor-mediated ingestion of EsIgG, and mannan at 20 mg/ml also failed to inhibit EsIgG ingestion . Pretreatment of adherent macrophages with 20 micrograms/ml of trypsin reduced the number of cells ingesting greater than or equal to 1 zymosan particles from 89 to 10% and those ingesting greater than or equal to 6 zymosan from 43 to 0%, whereas pretreatment with as much as 100 micrograms/ml of trypsin failed to decrease macrophage ingestion of EsIgG.(ABSTRACT TRUNCATED AT 400 WORDS) Ann Clin Res, 1986, 18(1), 13 - 7 Selenium in food and nutrition in Finland . An overview on research and action; Koivistoinen P et al.; For geochemical reasons Finland is a low-selenium area . In the 1960's several diseases associated with serious Se deficiency were observed in domestic animals . Selenium medication of animals and selenium supplementation of animal feeds from 1969 effectively eliminated these diseases . An extensive study of the trace element content of foods consumed in Finland in the 1970's demonstrated that the dietary intake of selenium was exceptionally low (25 micrograms/day/10 MJ) during the years when domestic grains were used . A study carried out in 1981 showed that supplementation of healthy middle-aged men with high selenium wheat or yeast or selenate double the glutathione peroxidase activity in platelets . Prospective epidemiological studies based on cohorts that were followed in the 1970's suggested that low selenium (less than 45 ng/ml serum) might be a risk factor for cardiovascular diseases and cancer . Technologies to increase the selenium content of foods and feeds were developed and an official decision was reached to add, starting in 1984, sodium selenate to the main fertilizers to increase the selenium content of domestic grain to about 100 micrograms/kg . This measure will increase the average selenium intake above 50 micrograms/d even in the years when grain with a high selenium content is not imported. Basic Life Sci, 1986, 37, 207 - 15 Recombinant DNA approaches to feline leukemia virus immunization; Luciw P et al.; We have utilized 2 recombinant DNA strategies for immunization against FeLV in cats: (a) modified live virus was attenuated by mutation and recombination, and (b) an immunogen, consisting of subunit envelope protein, was prepared in genetically engineered yeast . Results indicated that the genetically manipulated live virus preparations were not protective against FeLV challenge because they were either not attenuated in virulence or were not sufficiently antigenic . Immunization with yeast-synthesized FeLV envelope protein followed by the modified live virus gave protective immunity in cats under experimental conditions . Future immunization attempts will concentrate on enhancing the immunogenic potency of the yeast- synthesized FeLV envelope protein. Microbiol Immunol, 1986, 30(1), 1 - 11 Active substance of Histoplasma capsulatum that inhibits blastogenic response of lymphocytes; Yamamoto Y et al.; A substance inhibiting blast transformation of murine spleen lymphocytes stimulated with various mitogens, such as LPS, PHA, and PWM, was obtained from yeast-form cells of Histoplasma capsulatum . This active substance was partially purified from the cell-free extract by DEAE-Sepharose CL-6B column chromatography . As a result of this partial purification, the inhibitory activity was 1.26 micrograms/ml in terms of ID50 . Materials from H . capsulatum also inhibited blast transformation of murine spleen lymphocytes stimulated with the antigen PPD as well as mitogens LPS, PHA, and PWM . However, the con A-induced proliferative response was only slightly affected . A similar result was observed for the MLR . These inhibitory activities were abolished by heating at 70 C for 30 min . These results suggest that the heat-labile active substance produced by H . capsulatum might directly affect the lymphocytes, leading to inhibition of their blast transformation. Arch Dermatol Res, 1986, 279(1), 59 - 65 On the interaction between anthralin and mitochondria: a revision; Fuchs J et al.; Anthralin is an inhibitor of oxidative phosphorylation at concentrations found in vivo . ADP-stimulated oxygen consumption is diminished . Consequently, the rate of ATP synthesis is reduced and mitochondrial ATP content declines . Neither the isolated ATPase (F1F0-ATPase), nor the mitochondrial membrane-bound ATPase are influenced by the drug . Respiration under resting conditions is not affected . The experimental data unequivocally indicate that anthralin is not an uncoupler of oxidative phosphorylation, as previously stated . Furthermore, the interpretation that respiratory deficiency induced in yeast strains by anthralin is a consequence of petite mutations has to be reconsidered . Under in vivo conditions, anthralin inhibits respiration per se . Our experiments, including the electron spin resonance spectroscopy, reveal that anthralin alters mitochondrial membrane structure and function simultaneously . A redox or free-radical mediated step may be involved . In consequence, inhibition of ATP production occurs which may become the limiting factor for increased cellular metabolism in psoriasis. Mol Biochem Parasitol, 1986 Jan, 18(1), 103 - 12 Cysteine proteinase of Entamoeba histolytica . I . Partial purification and action on different enzymes; Scholze H et al.; A method for a 50-60-fold purification of a cysteine proteinase from trophozoites of Entamoeba histolytica using 35-80% ammonium sulphate fractionation, gel chromatography on Sephadex G-75, and preparative isoelectric focusing is described . The enzyme was examined for its proteolytic potencies towards native enzyme substrates . The amebic proteinase directly inactivates aldolase and glyceraldehyde-3-phosphate dehydrogenase from rabbit muscle as well as glucose-6-phosphate dehydrogenase from yeast . The inactivation of citrate synthase from porcine heart proceeds rather slowly, whereas malate dehydrogenase from porcine heart is not affected by the amebic proteinase under the condition used . With the exception of aldolase all inactivated enzyme substrates have been cleaved by limited proteolyses yielding major cleavage products . The inactivation of aldolase probably functions by the release of a small segment from a terminus being essential for aldolase activity. Curr Genet, 1986, 10(8), 625 - 30 Characterization of inverted repeats from plasmid-like DNAs and the maize mitochondrial genome; Braun CJ et al.; Integrated inverted repeat (IR) sequences similar to those of the S plasmids have been isolated from the genomes of the normal and S type male-sterile cytoplasms of maize mitochondria . The nucleotide sequences of both the IRs and their flanking regions have distinguished and characterized several different types of repeats . The repeats may be involved in the recombinational process that occurs continuously in the mitochondrial genome . One cloned fragment, derived from a fertile revertant and containing sequences similar to S-2, does not appear to act as a typical transposable element during reversion . Several of the flanking regions examined contain a small repeat of 34 base pairs, in which a nonanucleotide segment is found with similarity to the yeast mitochondrial promoter. Curr Genet, 1986, 10(7), 515 - 25 Analysis of the mitochondrial and nuclear genomes of two basidiomycetes, Coprinus cinereus and Coprinus stercorarius; Weber CA et al.; The mitochondrial and nuclear genomes of Coprinus stercorarius and C . cinereus were compared to assess their evolutionary relatedness and to characterize at the molecular level changes that have occurred since they diverged from a common ancestor . The mitochondrial genome of C . stercorarius (91.1 kb) is approximately twice as large as that of C . cinereus (43.3 kb) . The pattern of restriction enzyme recognition sites shows both genomes to be circular, but reveals no clear homologies; furthermore, the order of structural genes is different in each species . The C . stercorarius mitochondrial genome contains a region homologous to a probe derived from the yeast mitochondrial var1 gene, whereas its nuclear genome does not . By contrast, the C . cinereus nuclear, but not mitochondrial, genome contains a region homologous to the var1 probe . Only a small fraction of either the nuclear or mitochondrial genomes, perhaps corresponding to the coding sequences, is capable of forming duplexes in interspecies solution reassociations, as measured by binding to hydroxylapatite . Those sequences capable of reassociating were found to have approximately 15% divergence for the mitochondrial genomes and 7%-15% divergence for the nuclear genomes, depending on the conditions of reassociation. Cancer Surv, 1986, 5(1), 81 - 91 Biochemical and cellular determinants of bleomycin cytotoxicity; Sikic BI; Bleomycin is a mixture of cytotoxic glycopeptides which function as mininucleases, binding to DNA and producing single and double strand breaks by the formation of an activated oxygen complex . Bleomycin is an effective agent against a few human cancers, notably lymphomas, testicular and ovarian germ cell cancers and certain squamous carcinomas . Most human cancers are resistant to bleomycin a priori, however, and those which are initially sensitive frequently develop resistance to the drug during therapy . Several potential modes of resistance to bleomycin have been identified in cell culture and animal tumour models, although their relative importance in determining the responsiveness of human cancers to the drug is not well understood . Bleomycin is selectively toxic to cells in the M and G2 phases of the cell cycle, and generally more effective against actively dividing rather than resting cells . Thus, the cytokinetic state of the tumour cell population is an important determinant of drug activity . Oxygen is an essential substrate for bleomycin's action, with the degree of cytotoxicity directly related to ambient oxygen . Both acutely and chronically hypoxic cells form a substantial fraction of the cell population of many tumours, and may serve as a reservoir of cells resistant to bleomycin on this epigenetic basis . Metabolic inactivation of bleomycin is a mechanism of resistance to the drug in some cells and may influence toxicity in normal tissues . Bleomycin hydrolase activity is low in lungs and skin, the two major sites of normal tissue toxicities, and levels of this enzyme have been elevated in some but not all tumour cell lines selected for resistance to bleomycin . The capacity to repair or withstand single and double strand DNA breaks may also be an important determinant of resistance to the drug . Most yeast and mammalian cell mutants, which are hypersensitive to ionizing radiation because of defects in DNA repair, are also more sensitive to bleomycin than wild-type cells . A number of agents which interact with membranes or inhibit DNA repair, such as ethanol, lidocaine, verapamil and caffeine, have been reported to sensitize cells to bleomycin in vitro. Dev Biol Stand, 1986, 63, 141 - 6 A brief overview of the new vaccines against hepatitis B virus infection: immunogenic gene products and peptide analogues of antigenic epitopes; Vyas GN; Immunologically recognizable antigens encoded by hepatitis B virus (HBV) DNA include: (i) the surface antigen (HBsAg), (ii) the pre-S antigen, (iii) the X antigen (HBxAg) and (iv) the core/e antigens (HBcAg/HBeAg) . Each one of these antigens or their combination may be prepared for the next generation of vaccines against HBV infection . The synthesis of HBsAg by expression of recombinant DNA in the yeast system has now reached the stage of clinical trials and will certainly provide the first alternative to the currently licensed plasma-derived HBsAg vaccine . The recombinant vaccinia containing the gene encoding HBsAg and transfected cell-lines expressing HBsAg/pre-S gene products are also contenders for alternative vaccines . Synthetic peptide analogues produced by organic synthesis provide experimental immunogens whose potential for the third generation of vaccines appears promising . Among the following group of immunogenic synthetic peptide analogues (PA), PA (139-147) is more promising, because human antibodies in HBsAg-vaccinated individuals predominantly react with this amino acid sequence: HBsAg sequence PA 110-137, 117-137, 125-137, 134-146, 139-147, 138-149 . The N-terminal 22 amino acid sequence of the 55 residues preceding the HBsAg sequence, Pre-S (120-145), with the property of binding polymerized albumin . PA HBxAg sequence (100-115, 144-154) . PA'HBcAg sequence (73-84). J Biol Chem, 1985 Dec 25, 260(30), 16156 - 61 The Euglena gracilis chloroplast ribulose-1,5-bisphosphate carboxylase gene . I . Complete DNA sequence and analysis of the nine intervening sequences; Gingrich JC et al.; The nucleotide sequence of 6225 base pairs (bp) of Euglena gracilis chloroplast DNA including the complete DNA sequence of the chloroplast-encoded ribulose-1,5-bisphosphate carboxylase large subunit gene along with the flanking DNA sequences is presented . The gene is greater than 5.5 kilobase pairs in length and is organized as 10 exons coding for 475 amino acids, separated by 9 introns . The exons range in size from 45 to 438 bp, while the introns range in size from 382 to 568 bp . The introns have highly conserved boundary sequences with the consensus, 5'-N GTGTGGATTT...(intron)...TTAATTTTAT N-3' . The introns are 82-85 mol% AT, with a pronounced T greater than A greater than G greater than C base bias in the RNA-like strand . They do not appear to encode any polypeptides . In addition, the introns have a conserved sequence 30-50 bp from their 3'-ends with the consensus, 5'-TACAGTTTGAAAATGA-3' . The 5'-TACA sequence bears some homology to the 5'-end of the TACTAACA sequence found in a similar location in yeast nuclear mRNA introns . The conserved sequences of the Euglena rbcL introns may be indicative of a splicing mechanism similar to that of eucaryotic nuclear mRNA introns and group II mitochondrial introns. N Engl J Med, 1985 Dec 19, 313(25), 1586 - 90 The prospects for and pathways toward a vaccine for AIDS; Francis DP et al.; PIP: This article reviews prospects for a vaccine for acquired immunodeficiency syndrome (AIDS), considered the only certain barrier to further spread of the disease . The development of an effective vaccine against another retrovirus, feline leukemia virus, suggests the possibility that a retrovirus vaccine for humans might work . However, vaccine production depends on the ability to manufacture large quantities of a safe antigen that stimulates protective immunity when it is injected into humans . There are also many nonscientific problems that must be solved, including the reluctance of the private sector to invest in such a project . If it is found that the genetic variation of human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) is limited and predictable, vaccine-induced antibodies directed toward its structural proteins, especially envelope proteins, could protect against subsequent infection . Because retroviruses have a predilection for recombination and have been associated with malignant diseases, a live attenuated retrovirus vaccine is unlikely . A killed-virus vaccine should be more acceptable, but there are problems with selecting a cell line for producing the virus, choosing methods for purifying the viral antigens, and freeing them from viral nucleic acid . Cells derived from human tumors may be necessary to support the large-scale production of immunogenic antigens . Perhaps the best option at present is recombinant DNA technology . The advantage of antigen-production systems is that the infective virus cannot be produced because only a small portion of the viral genome is incorporated . Decisions must be made about which recombinant system to use (bacterial, yeast, or mammalian cells) and which antigen or antigens should be incorporated into the vaccine . Once expressed envelope proteins are available in adequate quantity and purity for testing, an evaluation pathway that will document safety and efficacy while minimizing the time for approval needs to be established . Arch Tierernahr, 1985 Dec, 35(12), 847 - 53 {Initial research on the use of mixed corn grain and stalk silage in broiler fattening}; Jeroch H et al.; The suitability of a corn and cob maize silage (CCM) as a component rich in energy in the fattening ration was investigated in a growth experiment with male broilers . The CCM silage with a dry matter content of 60.2% contained the following substances determining its value (per 1 kg dry matter of the feed): 102 g crude protein, 61 g crude fibre and 682 energetic feed units for chickens (EFUc) . CCM silage was either fed as a component of a feed mixture consisting of 70.5% CCM silage and 29.5% protein concentrate (all values of original substance) or both components of the ration were fed to broilers separately . The protein concentrate was composed as follows (values per kg): 650 g soybean oilmeal, 110 g fishmeal, 85 g tankage from rendering plants, 55 g torula yeast, 70 g mineral mixture and 30 g of a mixture of biologically active substances . The broilers of the control group received commercial fattening feed for broilers with coarse maize meal as cereal component . The feed mixture with CCM silage and separate CCM silage were accepted readily . When CCM silage and protein concentrate were offered alternatively, the same amount of CCM silage was consumed but 8% less protein concentrate . The broilers fed with CCM silage plus protein concentrate reached 96-97% of the live weight of the control animals (1.952 g/animal, 49th day), which received conventional feed, although their net energy intake was 10% lower . This proves a more favourable net energy expenditure for the test groups fed with CCM silage. Arch Biol Med Exp (Santiago), 1985 Dec, 18(3-4), 253 - 9 Search for compartments of glucose metabolism in the microinjected frog oocyte; Ureta T et al.; Microinjection of frog oocytes allows the modification of intracellular levels of substrates, intermediates, cofactors and enzymes . Use of labeled glucose at specific positions has led us to conclude that oocytes utilize glucose mainly for glycogen synthesis and to a lesser extent for the pentose-P pathway . Glycolysis, glycogenolysis and gluconeogenesis are not operative in these cells . The subject of compartmentation of glucose utilization has been addressed in this paper . First, we show that microinjection of glucose results in a 30-fold increase of carbon incorporation into glycogen when compared to oocytes incubated at saturating glucose concentrations . On the other hand, carbon incorporation into CO2, remains at about the same levels in both conditions Second, microinjection of NADP+ increases CO2 release and inhibits glycogen synthesis from glucose . Third, co-injection of unlabeled intermediates affects differentially glycogen synthesis and CO2 production from labeled glucose . Finally, microinjection of pure yeast hexokinase stimulates markedly 14CO2 release and inhibits glycogen synthesis . We conclude that two separate pools of glucose-6-P exists in oocytes: one pool is committed to the pathway of glycogen synthesis while a second pool serves as substrate for the operation of the pentose-P pathway. Mol Cell Biol, 1985 Dec, 5(12), 3560 - 76 Characterization of the multigene family encoding the mouse S16 ribosomal protein: strategy for distinguishing an expressed gene from its processed pseudogene counterparts by an analysis of total genomic DNA; Wagner M et al.; Two genes from the family encoding mouse ribosomal protein S16 were cloned, sequenced, and analyzed . One gene was found to be a processed pseudogene, i.e., a nonfunctional gene presumably derived from an mRNA intermediate . The other S16 gene contained introns and had exonic sequences identical to those of a cloned S16 cDNA . The expression of this gene was demonstrated by Northern blot analysis of nuclear poly(A)+ RNA with cDNA and unique sequence intron probes . Each S16 intron contains a well-preserved remnant of the TACTAAC motif, which is ubiquitous in yeast introns and known to play a critical role in intron splicing . A sequence comparison with two other mouse ribosomal protein genes analyzed in our laboratory, L30 and L32, revealed common structural features which might be involved in the control and coordination of ribosomal protein gene expression . These include the lack of a canonical TATA box in the -20 to -30 region and a remarkably similar 12-nucleotide pyrimidine sequence (CTTCCYTYYTC) that spans the cap site and is flanked by C + G-rich sequences . The nature of the other members of the S16 family was evaluated by three types of experiment: a DNase I sensitivity analysis to measure the extent of chromatin condensation; an analysis of the thermal stability of cDNA-gene hybrids to estimate the extent of divergence of each gene sequence from that of the expressed gene; and a restriction fragment analysis which distinguishes intron-containing genes from intronless processed genes . The results of these analyses show that all genes except the expressed S16 gene are in a condensed chromatin configuration associated with transcriptional quiescence; that most of the genes within the S16 family have sequences greater than 7% divergent from the expressed S16 gene; and that at least 7 of the 10 S16 genes lack introns . We conclude that the ribosomal protein S16 multigene family contains one expressed intron-containing gene and nine inactive pseudogenes, most or all of which are of the processed type. Mech Ageing Dev, 1985 Dec, 33(1), 103 - 13 Growth rate and life span in Drosophila V . The effect of prolongation of the period of growth on the total duration of life (J.H . Northrop, 1917)--revisited; Economos AC et al.; Sixty-eight years ago Northrop observed a constant life span in Drosophila after a progressive increase of the duration of development of the flies achieved by using a yeastless nutrient medium to which he added yeast with a progressively increasing delay . This evidence against the more recent concept of an increased life span following an experimentally decreased developmental rate has generally been ignored due, presumably, to the imprecise methodology employed by Northrop at a time that Drosophila research was just commencing . We describe here a study that aimed at re-examining and extending Northrop's work by developing the flies in either a yeastless or a lightly yeasted medium . While in a yeastless medium development of flies was virtually arrested until yeast was added, in the yeasted medium a slow growth of the larvae was possible before yeast was added . With another method, larval growth rate was reduced over the entire developmental period by adding a relatively low amount of yeast in four portions and with various delays between portions (the first portion being added without delay) . Our study confirmed the "Northrop-effect", i.e . the absence of an effect on life span from increased duration of development by a virtual arrest of growth of the larvae for a number of days . Further, it showed that manipulation of growth rate by portioning the yeast amount did not unequivocally support the concept that a lower growth rate leads to an increased life span. J Am Mosq Control Assoc, 1985 Dec, 1(4), 506 - 10 Feeding rate of larval Aedes vexans stimulated by food substances; Aly C; Feeding rates of fourth instar larvae of Aedes vexans were compared by counting substrate filled gut segments after exposure to food or inert particles . Food particles (wheat flour, fishmeal or yeast) were ingested approximately 3 times faster than inert particles (kaolin, pumice or synthetic cellulose) . Aqueous fishmeal extract accelerated ingestion of inert particles to the level of ingestion of food particles, demonstrating gustatory stimulation of larvae . Absolute amounts of ingested materials were calculated on the basis of dry weights of guts completely filled with test substrates . At 21 degrees C, 46-74 micrograms of food particles, and 15-33 micrograms of inert particles were ingested per larva during 10 min of exposure . In the subsequent time span, ingestion rates of food particles decreased continuously with satiation of larvae. Arch Biol Med Exp (Santiago), 1985 Dec, 18(3-4), 317 - 23 Pyruvate kinase: studies on affinity labeling and active-site structure using the rabbit muscle enzyme; Eyzaguirre J et al.; Important advances have been made in recent years in the study of the structure of pyruvate kinase: the amino acid sequence of the enzymes from chicken muscle and yeast have been established and the three-dimensional structure of the cat muscle enzyme has been determined at 0.26 nm resolution . Work in our laboratory has shown that dialdehyde-ADP (oADP) can be used as an affinity label of rabbit muscle pyruvate kinase: if the enzyme is incubated with cold oADP in the presence of high ADP concentrations, dialyzed and then incubated with 14C-oADP, the enzyme inactivates and one mole of radioactive oADP incorporates per mole of enzyme subunit . A labeled peptide with a molecular weight of about 5900 has been purified from a tryptic digest of the modified enzyme . The first 26 residues of the peptide have been sequenced and this sequence is identical to a region in the chicken muscle enzyme and a peptide isolated from the bovine muscle enzyme specifically labeled with trinitrobenzenesulfonate . High homology is also found with a region of the yeast enzyme . All this suggests that the isolated peptide is part of the active site; the modified amino acid, probably a lysine, seems to be located in one of the alfa helices of domain A of the enzyme, according to the x-ray data. An Acad Bras Cienc, 1985 Dec, 57(4), 497 - 506 Kinetic study of hemoglobin Porto Alegre {beta 9(A6)Ser----Cys} disulfide polymer reduction; Tondo CV et al.; The cleavage of HbPA disulfide polymer by GSH and its indirect cleavage by yeast glutathione reductase, via reduced glutathione is obtained . Decreasing the initial proportion of GSH in the hemolysate increases the formation of HbPA disulfide polymer . In the experimental conditions used, yeast glutathione reductase is unable to perform the direct cleavage of the mixed disulfide of HbPA and GSH, using it as substrate . The reduction of HbPA polymer to tetramers by DTE is analyzed by a pseudo-first-order kinetic and two rate constants are obtained . That of 265 X 10(-3) min-1 should be concerned with one disulfide of the closed ring and one of the open ring structure of dodecamer, while that of 38 X 10(-3) min-1 is related to disulfide reduction of the octamer . The enthalpy of activation values of 8.0 kcal.mol-1 an 17.4 kcal.mol-1 obtained, from the Arrhenius plot, for the "fast" and "slow" rate disulfide reduction, respectively, are indicative that a strong conformational strain of S--S bonds in the closed ring structure is maintained . The entropy of activation values of 24 e.u . and 52 e.u . are found for the activation of disulfides from dodecamers and octamers, respectively. Arch Biol Med Exp (Santiago), 1985 Dec, 18(3-4), 331 - 58 {Concurrence of multiple and integrated mechanisms in the modulation of enzyme activities: significance for the regulation of metabolic fluxes}; Niemeyer H et al.; The activity of some enzymes in a given metabolic pathway is modulated through multiple mechanisms, which operate in a simultaneous and coherent way to produce either stimulation or inhibition . The operation of these mechanisms is illustrated with several enzymes involved in glucose metabolism, by choosing examples from the presentations at the Symposium . Thus the reciprocal interactions of the regulatory mechanisms acting upon hexokinase D ('glucokinase'), phosphofructokinase, fructose 1,6-bisphosphatase and pyruvate kinase were discussed, as well as their relationships with the induction of enzyme conformational changes . In addition, the effects of covalent interconversions on glutamine synthetase activity were briefly analyzed . An outstanding feature exhibited by all these enzymes is the display of a great number of elasticity coefficients, which are differential quotients measuring the dependence of enzymatic activity on each variable that modulates it . A general assumption is that these enzymes make an important contribution to the control of the metabolic flux in which they participate . The flux control, however, appears to be shared in different degrees by all the components of the system, and may be quantified through the differential quotient denominated control coefficient . Some of the problems that emerge in any attempt to estimate these coefficients in the living cells are discussed . The problems derive partly from the complex subcellular structure, the formation of functional compartments resulting from reversible association of the enzymes, one to another and to different cellular components, and the actual state of cell water . These problems make that the results obtained with purified and highly diluted enzymes in most enzymological studies should not be extrapolated directly to what happens in vivo, without a careful evaluation of each particular case . The regulatory role of enzyme activity of fructose 2,6-bisphosphate and its eventual participation as an intermediary in the hormonal control of glycolytic and gluconeogenic fluxes are emphasized . The regulation of yeast fructose 1,6-bisphosphate activity is discussed in relation to the eventual role of allosteric modulators and covalents interconversions as signals for the initiation of intracellular degradation of the enzyme during catabolic inactivation. J Clin Invest, 1985 Dec, 76(6), 2368 - 76 Interaction of human monocytes, macrophages, and polymorphonuclear leukocytes with zymosan in vitro . Role of type 3 complement receptors and macrophage-derived complement; Ezekowitz RA et al.; Macrophages take up zymosan in the absence of exogenous complement via receptors for iC3b (type 3 complement receptors) acting with or without lectin-like receptors for mannosyl-fucosyl-terminated glycoconjugates . We previously provided evidence that macrophages themselves secrete complement-alternative pathway components able to opsonize zymosan locally (Ezekowitz et al., J . Exp . Med . 1984 . 159:244-260) . We show here that covalently bound C3 cleavage products C3b and iC3b can be eluted from zymosan particles cultivated with 36-h adherent human monocytes in the absence of serum . The ligand binding site of type 3 complement receptors is involved in macrophage-zymosan interactions as shown by inhibition studies of zymosan binding and uptake with Fab fragments of anti-C3 antibodies and monoclonal antireceptor antibodies M01 and OKM10 . In contrast, antibody IB4, which binds to a receptor epitope distinct from the binding site, does not inhibit zymosan uptake . Selective modulation of macrophage receptors onto anticomplement receptor antibody and mannose-rich yeast mannan, respectively, confirms that the complement and lectin-like receptors are distinct . Human polymorphonuclear leukocytes, which express receptors for complement, but are not known to secrete complement proteins, bind and ingest only exogenously opsonized zymosan . Unopsonized zymosan is a poor trigger of respiratory burst activity in neutrophils or 7-d adherent human macrophages, but induces cell aggregation and secretion of large amounts of superoxide anion when these cells are co-cultivated in serum-free medium and challenged with zymosan . Our studies indicate that complement and/or other products synthesized by macrophages at extravascular sites could play an important role in opsonization and lysis of pathogens able to activate the alternative pathway and mediate macrophage-neutrophil collaboration in first-line host defence. J Mol Biol, 1985 Nov 20, 186(2), 321 - 35 Organization of the actin multigene family of Dictyostelium discoideum and analysis of variability in the protein coding regions; Romans P et al.; There are 17 to 20 actin genes in the genome of the cellular slime mold Dictyostelium discoideum . Genomic clones of 15 of the genes have been isolated . Extensive nucleotide sequence within the protein-coding regions has been determined, including the complete nucleotide sequence of four genes representing the three distinct evolutionary groups of Dictyostelium actin genes . All are similar to mammalian cytoplasmic actins at diagnostic amino acid positions, and there is generally less variability among Dictyostelium actin genes than among Drosophila actin genes . Two genes, Actins 3-sub 1 and 3-sub 2 differ substantially from all the rest in terms of replacement amino acid substitutions and probably encode actin-related proteins rather than bona fide actins . Each contains several amino acid substitutions that should alter the secondary structure of the resulting proteins, and Actin 3-sub 2 encodes four additional amino acids at the C terminus . This gene is as divergent from other Dictyostelium actin genes as is the yeast or a soybean actin gene . At present, evidence suggests that all 15 genes examined are expressed, except the previously identified Actin 2-sub 2 . We suggest that Dictyostelium might maintain a high number of functional actin genes for the purpose of regulating the level of actin synthesis within narrow limits, rather than because most genes perform different functions. Experientia, 1985 Nov 15, 41(11), 1421 - 2 Lowering of liver acetaldehyde but not ethanol concentrations by pretreatment with taurine in ethanol-loaded rats; Watanabe A et al.; A rise in blood and liver acetaldehyde concentrations following ethanol loading (1.5 g/kg b.wt) was significantly reduced when rats were pretreated orally with taurine (0.5 g/kg), a potent in vitro activator of yeast aldehyde dehydrogenase . This taurine pretreatment produced a 4-fold increase in liver taurine content. Arch Biochem Biophys, 1985 Nov 15, 243(1), 46 - 61 Purification and properties of rabbit liver cathepsin M and cathepsin B; Erickson-Viitanen S et al.; Cathepsins M and B from rabbit liver lysosomes were separated by chromatography on Ultrogel AcA34 at low ionic strength and purified to homogeneity, and their catalytic and molecular properties were compared . Cathepsin M was relatively inactive with synthetic peptide substrates . Thus, it hydrolyzed benzoyl arginine naphthylamide at only one-fifth the rate observed with cathepsin B, and no activity was detected with Gly-Phe naphthylamide which is a relatively good substrate for cathepsin B . On the other hand, cathepsin M exhibited a preference for protein substrates . It was more active than cathepsin B in catalyzing the inactivation of the following enzymes: rabbit muscle or liver fructose-1,6-bisphosphate aldolases, rabbit liver fructose-1,6-bisphosphatase and pyruvate kinase, yeast glucose-6-phosphate dehydrogenase, and rabbit muscle glyceraldehyde-3-phosphate dehydrogenase . With glucagon as substrate, both enzymes showed similar peptidyl dipeptidase activities with some minor differences in peptide bond specificity . Cathepsins M and B are similar in size, with apparent molecular weights of 30,200 for cathepsin M and 28,800 for cathepsin B, and in amino acid composition and carbohydrate content . Each contains approximately 2-3 equivalents/mol glucosamine, 3 equivalents/mol mannose, and no fucose or galactosamine . They also show similar microheterogeneity in sodium dodecylsulfate-gel electrophoresis and isoelectric focusing; this microheterogeneity is probably related to differences in glycosylation . Extensive homology in primary structure for the two proteins was indicated by the similar patterns of peptides formed on digestion with trypsin. J Biol Chem, 1985 Nov 15, 260(26), 14173 - 9 Fructose-1,6-bisphosphatase from rat liver . A comparison of the kinetics of the unphosphorylated enzyme and the enzyme phosphorylated by cyclic AMP-dependent protein kinase; Ekdahl KN et al.; A purification procedure for rat hepatic fructose-1,6-bisphosphatase, described earlier, has been improved, resulting in an enzyme preparation with a neutral pH optimum and with both phosphorylatable serine residues present . The subunit Mr was 40,000 . Phosphorylation in vitro with cyclic AMP-dependent protein kinase resulted in the incorporation of 1.4 mol of phosphate/mol of subunit and led to an almost 2-fold decrease in apparent Km for fructose-1,6-bisphosphate . In contrast to yeast fructose-1,6-bisphosphatase, fructose-2,6-bisphosphate had no effect on the rate of phosphorylation or dephosphorylation of the intact enzyme . The effects of the composition of the assay medium, with regard to buffering substance and Mg2+ concentration, on the apparent Km values of phosphorylated and unphosphorylated enzyme were investigated . The kinetics of phosphorylated and unphosphorylated fructose-1,6-bisphosphatase were studied with special reference to the inhibitory effects of adenine nucleotides and fructose-2,6-bisphosphate . Unphosphorylated fructose-1,6-bisphosphatase was more susceptible to inhibition by both AMP and fructose 2,6-bisphosphate than phosphorylated enzyme, at high and low substrate concentrations . Both ATP and ADP had a similar effect on the two enzyme forms, ADP being the more potent inhibitor . Finally, the combined effect of several inhibitors at physiological concentrations was studied . Under conditions resembling the gluconeogenic state, phosphorylated fructose-1,6-bisphosphatase was found to have twice the activity of the unphosphorylated enzyme. Eur J Biochem, 1985 Nov 4, 152(3), 625 - 31 Ribosomes are stalled during in vitro translation of alfalfa mosaic virus RNA 1; Lindhout P et al.; In the presence of plant tRNAs the full-length translation product of alfalfa mosaic virus RNA 1 is produced in rabbit reticulocytes only at low mRNA concentration . At higher mRNA concentration translation is restricted to the 5' half of RNA 1 . At high mRNA concentration the full-length product can be formed when additional plant tRNA and glutamine are supplied to the translation mixture . In contrast, in the presence of yeast or calf liver tRNA the translation pattern of alfalfa mosaic virus RNA 1 always results in the synthesis of the full-length product . Pulse-chase experiments in the presence of plant tRNAs show that the ribosomes pause at several positions in the 5' half of RNA 1 . The pausing time is different at the different 'halting places' . Protein synthesis is resumed upon addition of glutamine, even when the addition is delayed for more than 3 h after the start of protein synthesis . Only one tRNA species, purified from wheat germ or tobacco, could promote full-length translation of RNA 1 . This tRNA can be charged with glutamine . Analysis of the position of glutamine codons on RNA 1 shows a correlation between the positions of the CAA codons and the halting places of the ribosomes . The CAA codon (for any other codon) on its own cannot be responsible for the pausing of the ribosomes, since a variety of RNAs, known to contain all sense codons, are translated efficiently in rabbit reticulocyte lysates in the presence of plant tRNAs . Apparently other elements can restrict decoding of normal codons during protein chain elongation. Vopr Virusol, 1985 Nov-Dec, 30(6), 697 - 700 {Comparative study of the antiviral activity of natural double-stranded RNAs in experimental tick-borne encephalitis}; Knoroz MIu et al.; A comparative study of the antiviral effect of interferon inducers from the group of natural double-stranded RNAs (yeast plasmid dsRNA, phage phi 6 and phage f2 dsRNAs was carried out on the model of experimental tick-borne encephalitis . The possibility of inducing up to 60% protection against 10 LD50 of TBE virus by prophylactic inoculation of interferon inducers alone was demonstrated . The therapeutic effect was observed only with yeast dsRNA (30% protection when the inducer was administered 4 hours after virus infection of mice) . The prophylactic effect of inoculation of interferon inducers (yeast dsRNA and f2 dsRNA) to immune mice correlated with the protective effect of inducers alone . At the same time, the therapeutic effect of inoculation of yeast dsRNA to immune animals (4 hours after TBE virus, 40% protection) was more marked . In the therapeutic use of f2 dsRNA for pre-immunized animals a synergetic effect of the preparation was observed (56.7% protection in 4 hours and 26.7% protection 24 hours postinfection). Mech Ageing Dev, 1985 Nov, 32(2-3), 193 - 204 Growth rate and life spain in Drosophila . IV . Role of cell size and cell number in the biphasic relationship between life span and growth rate; Economos AC et al.; The patterns of variation of wing cell size and number were studied under developmental conditions leading to a biphasic relationship between life span and growth rate while duration of development remained constant (development on an agar-only medium with a varying added yeast amount, constant temperature (25 degrees C) and constant larval density) . Across the yeast range, a 125% increase of body weight was accompanied by a roughly 30% increase in the wing linear dimensions, wing cell size and wing cell number while estimated duration of cell division and its reciprocal mitotic division rate remained constant . Furthermore, cell size (but not cell number) varied with growth rate in a similar biphasic pattern to that observed for life span . Finally, from a simultaneous examination of the covariation patterns of life span, growth rate, cell size and cell number with decreasing yeast amount, it became apparent that there was a "critical" yeast amount, approximately 125 mg/120 eggs, below which: (a) cell number abruptly started to decrease linearly from a roughly constant value; (b) the rate of the slow decrease of cell size now tripled and that of growth rate increased even more; and (c) life span which, in the upper yeast range, increased slowly with decreasing yeast, apparently reached a maximum at the critical yeast level and decreased three times faster below that level . These data taken together suggest that: (i) the decrease of all parameters (including life span) below the critical yeast level results from a presumably suboptimal or disturbed development because of and in proportion to the lack of nutrients and (ii) the increase of life span with decreasing yeast amount above the critical yeast level has not been definitely explained but some possibilities are suggested such as changes in subcellular organelle numbers, size and/or functional properties, or other changes due to a phenomenon equivalent to food restriction in rats, probably without changes in overall metabolic rate of the flies. Am J Clin Nutr, 1985 Nov, 42(5), 829 - 35 Selenium status of exclusively breast-fed infants as influenced by maternal organic or inorganic selenium supplementation; Kumpulainen J et al.; A longitudinal dietary Se supplementation study on lactating mothers was performed to determine the possibilities of improving the Se status of exclusively breast-fed infants . A total of 200 mothers randomized into three groups received either no Se supplements, 100 micrograms of selenite, or 100 micrograms of yeast-Se daily . Maternal and infant serum Se concentrations showed a linear correlation during exclusive breast-feeding . Yeast-Se in the dose administered was safe and more effective than selenite in increasing the Se concentrations of maternal serum and milk, and infant serum . Th