- Volume 131, Issue 09, 1985
Volume 131, Issue 09, 1985
- Sgm Special Lecture
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- Biochemistry
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Enzymes of Intermediary Carbohydrate Metabolism in Ureaplasma urealyticum and Mycoplasma mycoides subsp.mycoides
More LessSummary: Cell extracts of Ureaplasma urealyticum and Mycoplasma mycoides were examined for enzymes of intermediary carbohydrate metabolism using a sensitive radiochemical assay procedure. For M. mycoides, the enzyme activities detected were supporting evidence for the existence of a glycolytic pathway giving lactate anaerobically and acetate aerobically. U. urealyticum also had activities of many glycolytic enzymes. Enzymes of the pentose phosphate pathway occurred in both M. mycoides and U. urealyticum Their presence allowed the proposal of a sequence for the synthesis from glycolytic pathway intermediates of ribose 5-phosphate, and hence phosphoribosyl diphosphate, for the synthesis of nucleotides. Pathways for the further metabolism of deoxyribose I-phosphate and ribose 1-phosphate produced from nucleoside phosphorylase reactions operated in extracts from both organisms.
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Oxygen Affinities of the Bioluminescence Systems of Various Species of Luminous Bacteria
More LessSummary: O2 affinities of the bioluminescence systems have been measured in five species of luminous bacteria. Photobacterium phosphoreum He-1a, recently isolated from a fish light-organ, showed halfmaximal bioluminescence at 0·015 µM-O2 whereas another symbiotic strain (PJ-1a) gave a 33-fold higher value. Vibrio fischeri MJ-1 gave a value of 0·60 µM-O2, and the symbiotic Photobacterium leiognathi LN-la gave half maximal emission at 0·7 µM-O2. These results indicate the importance of strain selection for sensitive O2 measurements.
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The Generation of Metronidazole Radicals in Hydrogenosomes Isolated from Trichomonas vaginalis
More LessSummary: The nitro radical-anion of the anti-trichomonal drug metronidazole has been detected by electron spin resonance spectrometry under anaerobic conditions in suspensions of intact hydrogenosomes isolated from the parasitic protozoon Trichomonas vaginalis. Metronidazole reduction was driven by pyruvate, but progressive damage to the radical generating system was observed. Quenching of signals due to metronidazole radicals by chromium oxalate suggests that the radicals generated within the organelle can cross the hydrogenosomal membrane into the external medium. Even if a similar process of radical migration occurs in vivo, it seems likely that intrahydrogenosomal damage may explain drug action.
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Species of Bacillus That Make a Vegetative Peptidoglycan Containing Lysine Lack Diaminopimelate Epimerase but Have Diaminopimelate Dehydrogenase
More LessSummary: Lysine was found in the vegetative peptidoglycan of Bacillus sphaericus (23 strains), and of the related species Bacillus pasteurii and Bacillus globisporus. None of these organisms formed diaminopimelate epimerase, but all contained diaminopimelate dehydrogenase. All other species of Bacillus studied had diaminopimelate in their walls, and produced diaminopimelate epimerase and N-acetyldiaminopimelate deacetylase, but not diaminopimelate dehydrogenase. One exception, Bacillus macerans, contained all three of these enzymes; diaminopimelate (and no lysine) was found in its walls. A new spectrophotometric assay for diaminopimelate epimerase was developed, which had advantages over the previous methods.
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The Role of Cytochromes and Blue Copper Proteins in the Oxidation of Methanol and Methylamine in Organism 4025, an Obligate Methylotroph
More LessSummary: Organism 4025 contained only b-type and c-type cytochromes. In the absence of any a-type cytochrome oxidase it was concluded that respiration in these bacteria is catalysed entirely by way of the o-type cytochrome oxidase. After growth on methanol, the soluble protein contained cytochromes c H and c L, and a single blue copper protein of unknown function, ‘azurin’. After growth on methylamine the soluble proteins were strikingly different. The total concentration of soluble cytochrome c was about 70% lower; cytochrome c L was about 65%, and cytochrome c H about 16% of the concentrations present after growth on methanol. Although some ‘azurin’ was still present, a second copper protein, amicyanin (94% of the total), was induced during growth on methylamine. The concentration of this protein was considerably higher than that of blue copper proteins measured in other bacteria and 35 times higher than the concentration in the facultative methylotroph Pseudomonas AMI during growth on methylamine. It is the very high concentration of amicyanin that gave suspensions of methylamine-grown organism 4025 their blue-green colour. All of the soluble cytochrome c, and all of the methanol dehydrogenase, methylamine dehydrogenase and blue copper proteins were located in the periplasmic fraction. All these results are consistent with the conclusion that the main electron acceptor for methylamine dehydrogenase in organism 4025 is amicyanin.
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The Role of a Methanol Dehydrogenase Modifier Protein and Aldehyde Dehydrogenase in the Growth of Pseudomonas AM1 on 1,2-Propanediol
More LessPure methanol dehydrogenase of Pseudomonas AMI oxidizes propanediol in a transitory fashion when measured in a dye-linked assay with phenazine ethosulphate (PES) as electron acceptor. It was shown that the transitory nature of this oxidation is not because the product (lactaldehyde) is an inhibitor but because the dehydrogenase is inactivated by PES. Substrates having low affinities for the enzyme, such as propanediol, are unable to protect against this inactivation. A ‘stimulatory factor’, previously shown to facilitate the continuous oxidation by methanol dehydrogenase of propanediol to lactate, was shown to consist of two proteins, a modifier protein (M-protein) and an aldehyde dehydrogenase. The M-protein increased the affinity of methanol dehydrogenase for propanediol; this enabled the substrate to protect the enzyme against inactivation by PES, and it facilitated the continuous oxidation of low concentrations of propanediol to lactaldehyde. The M-protein was purified almost to homogeneity (more than 95% pure) and shown to be an acidic, dimeric protein having subunits of molecular weight 64000. The second protein component of the ‘stimulatory factor’ was a dye-linked aldehyde dehydrogenase which oxidized lactaldehyde to lactate but which had a greater affinity for longer-chain normal aliphatic aldehydes and the following characteristics: pH optimum, 7-0; isoelectric point, 4 0; molecular weight, 115000; and K m for lactaldehyde, 16 mm.
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Dimorphism in Candida albicans: Contribution of Mannoproteins to the Architecture of Yeast and Mycelial Cell Walls
More LessSummary: Wall mannoproteins of the two (yeast and mycelial) cellular forms of Candida albicans were solubilized by different agents. Boiling in 2% (w/v) SDS was the best method, as more than70% of the total mannoprotein was extracted. Over 40 different bands (from 15 to 80 kDal) were detected on SDS-polyacrylamide gel electrophoresis of this material. The residual wall mannoproteins were releasedafter enzymic (Zymolyase and endogenous wall β-glucanases) degradation of wall glucan, suggesting that theyare covalently linked to this structural polymer. Four bands (of 160 kDal, 205 kDal and higher molecular mass) were observed in the material released from yeast walls but only the two smaller components weredetected in the material obtained from mycelial walls. Moreover, the mannoproteins of high molecular mass, which are covalently linked in walls of normal cells, were not incorporated into walls of regeneratingprotoplasts, but non-covalently linked mannoproteins were retained from the beginning of the process.
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- Development And Structure
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Hybridization of Rhizopus Species
More LessSummary: The progeny resulting from crosses between Rhizopus microsporus and R. rhizopodiformis were analysed for a number of morphological characters and the ability to produce either zygospores or azygospores. The interspecific crosses resulted in relatively stable cultures exhibiting intermediate morphology and producing only azygospores. The results suggest that the progeny are diploid or aneuploid, which leads to heterozygosity, particularly with respect to mating type.
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The Involvement of Cell Wall Expansion in the Two Modes of Mycelium Formation of Candida albicans
More LessSummary: When budding cells of Candida albicans are starved for 20 min and then diluted into fresh nutrient medium at 37 °C, pH 6.7, they form mycelia by two alternative modes. For cells with small buds, the bud expands apically, resulting in a transiently tapered daughter cell. With continued growth, the daughter cell tapers into an elongated mycelium. For cells with large buds, the bud completes expansion in the budding form, the mother cell and then the daughter bud evaginate, and the evaginations grow as mycelia. The present study investigates whether the temporal and spatial changes in the zones of wall expansion during bud growth are involved in the two modes of mycelium formation. Data are presented which demonstrate that the transition circumference which determines the two modes of mycelium formation and the transition circumference at which the active apical expansion zone shuts down are both 7 µm. This exact correlation suggests that starved cells with buds with a circumference of less than 7 µm form mycelia in the tapering mode due to the reactivation of the still present apical expansion zone, and that starved cells with buds with a circumference greater than 7 µm complete bud growth by general expansion due to the absence of the apical expansion zone at the time of starvation.
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- Genetics And Molecular Biology
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Exclusion by the IncI Plasmid R144 Determined by Measuring DNA Transfer in Escherichia coli Conjugations
More LessSummary: Exclusion specified by the IncI plasmid R144 was determined by measuring the amount of donor DNA transferred to appropriate recipient cells. When recipient cells harboured an R144-derived Exc+ recombinant plasmid, the exclusion value determined in that way was comparable with the exclusion value determined by measuring the efficiency of transconjugant colony formation. When recipient cells harboured the plasmid R144 drd-3, the exclusion value determined by measuring the amount of donor DNA transferred to recipient cells appeared more valid than the value determined by measuring transconjugant colony formation.
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Mutation Affecting Resistance of Escherichia coli K12 to Nalidixic Acid
More LessSummary: A new mutation, nalD, determining resistance of Escherichia coli to nalidixic acid (NAL) is reported. The nalD mutant described is resistant to NAL at 37°C but sensitive at 30 C. It is defective in penetration of NAL and glycerol through the outer membrane at 37°C. The nalD mutation is located half-way between 89 and 89.5 min on the E. coli genetic map.
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Growth Inhibition of Escherichia coli by E Colicin Plasmids
More LessSummary: Plasmids were isolated from E colicinogenic strains and transformed into prototrophic Escherichia coli K12 strain DB364. Screening of E colicinogenic transformants for growth on defined medium revealed an apparent amino acid auxotrophy mediated by E4 and, to a lesser extent, E colicin plasmids. The auxotrophy was further investigated in E4 colicinogenic strains. From such auxotrophic transformants, denoted Pmi+ (plasmid-mediated inhibition of growth). Pmi− variants were obtained at a frequency of 3 x 10−4 per bacterium. Plasmid loss was not detected among Pmi− clones. Isolation of E4 colicin plasmids from Pmi− clones and re-transformation of strain DB364 with these plasmids showed that 40% of the plasmids were unable to inhibit growth of DB364 and were inferred to have alterations in an E4 colicin plasmid gene termed pmi. All such plasmids were indistinguishable from native E4 colicin plasmids, with respect to colicin immunity, colicin production and excretion, and sensitivity to lysis by mitom C. Experiments examining the nutritional basis of the plasmid-mediated auxotrophy indicated that at least seven amino acids, isoleucine, leucine, valine, arginine, methionine, serine and glycine, were involved in the auxotrophy. However, supplementation with only these seven amino acids did not completely restore growth. Assays of the activities of enzymes involved in amino acid biosynthesis in colicinogenic and non-colicinogenic strains under repressing and derepressing growth conditions suggested that E4 colicin plasmids did not repress synthesis of the implicated amino acids.
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Isolation and Characterization of RNA Polymerase from Vegetative and Symbiotic Forms of Rhizobium japonicum
More LessSummary: RNA polymerase was purified from both vegetative and symbiotic forms of Rhizobium japonicum strain 3I 1b 110 and the physical and transcriptional properties of the enzyme were compared. The subunit composition of the enzyme from both sources appeared similar when analysed by SDS-polyacrylamide gel electrophoresis. Removal of an 82 kDal protein from the purified enzyme from either source, using procedures developed for isolation of the sigma factor from Escherichia coli RNA polymerase, resulted in a decreased ability of the enzyme to utilize phage T4 DNA as a template in vitro. These results indicate that the 82 kDal protein may act as a sigma-like factor for the RNA polymerase of R. japonicum. The transcriptional specificity of the enzyme from both sources was similar using a variety of exogenous DNA templates. There were no apparent differences in the kinetic properties of the enzyme from both sources, or in the specificity of promoter utilization when phage T7 DNA was used as a template. This would indicate that a novel form of RNA polymerase may not be responsible for the transcription of nif genes in the symbiotic state.
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Rhizobium Population Genetics: Enzyme Polymorphism in Isolates from Peas, Clover, Beans and Lucerne Grown at the Same Site
More LessSummary: Isolates of Rhizobium meliloti and of R. leguminosarum biovars viceae, trifolii and phaseoli were obtained from a single site in Norfolk, England, and examined by enzyme electrophoresis of glucose-6-phosphate dehydrogenase, superoxide dismutase, β-galactosidase and esterases. All the enzymes had mobility variants, but the variation of the different enzymes was highly correlated, so that only a restricted number of combinations (electrophoretic types, ETs) were found. Some ETs were confined to a single biovar, but others were shared amongst R. leguminosarum biovars viceae, trifolii and phaseoli. Most R. meliloti isolates were quite distinct from those of R. leguminosarum. Electrophoresis of total soluble protein in the presence of sodium dodecyl sulphate revealed variation that correlated with the ET rather than with the host range. It is suggested that the Rhizobium isolates from this site comprise a number of genetically distinct lineages, some of which may carry any of several different host-range determinants, and which therefore appear in more than one biovar.
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spoVIC, a New Sporulation Locus in Bacillus subtilis Affecting Spore Coats, Germination and the Rate of Sporulation
More LessSummary: A mutation near cysB on the Bacillus subtilis chromosome marks a new sporulation locus, spoVIC. It causes spores to germinate more slowly than those of the wild-type under all conditions and, from indirect evidence, it does not appear to alter the affinity for the germinant l-alanine. The mutant spores have some deficiency of coat proteins (particularly the alkalisoluble coat protein, M r = 12000) and the spore coat layers are disorganized. The mutant strain grows normally and sporulates normally until stage II, after which its sporulation is delayed by about 2 h compared to that of the wild-type. This delay results in the prolonged synthesis of some coat proteins and the late synthesis of others. The abnormal coat may be the cause of the germination deficiency. A double mutant strain carrying the spoVIC610 mutation together with gerE36 sporulates slowly. Its spores have very little coat protein, are sensitive to heat, lysozyme and organic solvents, but germinate as well as the strain carrying the spoVIC mutation alone. The role of the spore coat in germination is discussed in the light of these findings.
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Protease Production during Sporulation of Germination Mutants of Bacillus subtilis and the Cloning of a Functional gerE Gene
More LessSummary: Early in sporulation, cells of wild-type Bacillus subtilis produce three proteases (b, c and d) with monomeric M r values of about 65000, 53000 and 43500, anda further protease, e (M r about 30000) at the time of coat assembly. An additional protease, f (M r about 15000) appears transiently in sporangia at about the time of spore release. Three strains with defective spore coats were examined for alterations in sporulation proteases. A strain carrying the gerE36 mutation produces b, c and d normally, fails to produce e and accumulates f on or inits spores. A strain carrying the spoVIC610 mutation produces normal quantities of proteases b, c and d, but has a reduced amount of proteases e and f. A strain carrying both the gerE36 and the spoVIC610 mutations accumulates neither protease e nor f. The wild-type allele of the gerE gene was cloned in the vector, phage ϕ105J9. Complementation tests with the cloned gene showed that the gerE36 mutation is recessive to the wild-type allele.
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Transposon Mutagenesis of Pseudomonas solanacearum: Isolation of Tn5-Induced Avirulent Mutants
More LessSummary: Transposon mutagenesis in a tomato isolate of Pseudomonas solanacearum (strain Kourou) is reported, using Tn7 and Tn5 inserted in suicide conjugative plasmids. Whereas Tn7 integrates at high frequency in a particular site of the the genome, Tn5 appears to transpose much more randomly, allowing isolation of auxotrophic mutants with a frequency of 0.35%. The mutants showed a wide range of nutritional requirements. Following Tn5 mutagenesis, screening of 8250 clones on axenic tomato seedlings led to the isolation of 12 avirulent mutants. Southern blot analysis revealed that, for avirulent mutants, insertion of Tn5 occurred in at least 10 different EcoRI restriction fragments. Additional independent insertions of IS50 were also detected in four of these mutants. For each mutant, transformation experiments demonstrated that the Tn5-encoded kanamycin resistance and the avirulent phenotype are linked. Based on their ability or inability to induce a collapse of tobacco leaf parenchyma, and on the timing of reaction of the plant, avirulent mutants have been divided in to two and possibly three groups.
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Isolation and Preliminary Characterization of Lytic and Lysogenic Phages with Wide Host Range within the Streptomycetes
More LessSummary: Examination of approximately 700 soil samples yielded about 100 actinophages. Restriction analysis of phage DNA indicated that 57 are unique, and of these, 20 produce turbid plaques on one or more of the streptomycetes tested. Five phages are shown to insert into the genome of Streptomyces avermitilis. None of the phages was able to perform generalized transduction of S. avermitilis.
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Isolation and Characterization of two Phages for Gluconobacter oxydans
Summary: Two bacteriophages, designated GW6210 and JW2040, were isolated from decaying apples using Gluconobacter oxydans ATC 621 and G. oxydans VPI 204JW, respectively. Electron microscopy showed that phage GW6210 belonged to group A and phage JW2040 to group C of Bradley's morphological classification. Phage GW6210 was unusually large, with a head diameter of 170 nm. Both phages contained double stranded DNA. The G + C content of the DNA of phage GW6210 was 293 mol % (T m), and the size of the genome was approximately 250-300 kb. The size of the DNA of phage JW2040 was found to be 37 kb and the G + C content was 565 mol% (T m). The host ranges of both phages were determined using 54 Gluconobacter, 52 bacter and three Pseudomonas strains. Only the Gluconobacter strains were hosts for these phages.
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- Pathogenicity And Medical Microbiology
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Three Immunity Types of Klebicins which Use the Cloacin DF13 Receptor of Klebsiella pneumoniae
More LessSummary: We have investigated a group of bacteriocinogenic strains used in the epidemiological investigation of Klebsiella infections. Transfer of plasmids from these strains to laboratory trains allowed the identification of three klebicins which use the cloacin DF13 receptor in Klebsiella but are of three distinct immunity types. These klebicins use the ferric-aerobactin determined by ColV-K30 in Escherichia coli, which is also used by cloacin DF13. We propose to call them group A klebicins, of immunity types A1, A2 and A3. On the basis of ammunity, cloacin DF13 also belongs to the klebicin A1 group.
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The Possession of Three Novel Coli Surface Antigens by Enterotoxigenic Escherichia coli Strains Positive for the Putative Colonization Factor PCF8775
More LessSummary: A possible colonization factor, E8775, has previously been described for enterotoxigenic Escherichia coli strains of serogroups O25, O115 and O167. Re-examination of these strains by immunodiffusion has revealed that the antigenic nature of this factor, renamed putative colonization factor (PCF) 8775, is more complex than was first thought. All the strains of serogroup O25 tested possessed two antigenic components, termed CS4 and CS6, and gave mannose-resistant haemagglutination (MRHA) of human and bovine erythrocytes. Spontaneous variants possessing CS6 only did not give MRHA. Strains of serogroups O115 and O167 had the antigenic components CS5 and CS6, and gave MRHA of human, bovine and guinea-pig erythrocytes. Using immune electron microscopy, the components CS4 and CS5 were identified as fimbriae. No fimbriae were associated with CS6.
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An Ultrastructural Study of the Gastric Campylobacter-like Organism ‘Campylobacter pyloridis’
D. M. Jones, A. Curry and A. J. FoxSummary: Microaerophilic spiral organisms may be isolated frequently from samples of gastric mucus taken from patients undergoing gastroscopy. The ultrastructure of these gastric campylobacter-like organisms (‘Campylobacter pyloridis’) shows that they have greater affinities with Spirillum than with Campylobacter.
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Immunochemical Characterization of the Outer Membrane Complex of Serratia marcescens and Identification of the Antigens Accessible to Antibodies on the Cell Surface
More LessSummary: Serratia marcescens New CDC O14:H12 contains major outer membrane proteins of 43.5 kDal, 42 kDal (the porins) and 38 kDal (the OmpA protein) which can be separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Immunoblotting of whole cell or outer membrane preparations using antiserum raised against the whole cells revealed similar complex patterns of antigens. The OmpA protein was the major immunogen, although six other outer membrane proteins were also detected; the porins reacted only weakly with antibodies in this system. Immunoabsorption of antisera with whole cells showed that only the O antigenic chains of lipopolysaccharide and the H (flagella) antigens were accessible to antibody on the cell surface. Failure to detect the OmpA protein and other envelope antigens in this way suggests that their antigenic sites are not able to react with antibodies and are possibly masked by the O antigen.
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The Outer Membrane of Treponema pallidum: Biological Significance and Biochemical Properties
More LessSummary: Rabbits infected intravenously with Treponema pallidum were not markedly febrile, and the pyrogenicity of treponeme preparations administered intravenously to rabbits was negligible. The antibiotic polymyxin B did not induce any ultrastructural changes on the treponemal surface and was not lethal (immobilizing) for T. pallidum, which was, however, highly susceptible to detergents such as SDS. Extraction of treponemes with Triton X-100 removed the outer membrane (despite the presence of Mg2+) as shown by electron microscopy, and solubilized a limited number of proteins detectable by SDS-PAGE, including a dominant antigen (47 kDal) demonstrated by immunoblotting. None of the proteins were heat-modifiable. Periodic acid-silver staining of polyacrylamide gels for carbohydrate together with protease K digestion did not demonstrate major carbohydrate components in whole treponemes, or in the Triton-soluble fraction. Surface iodination of intact treponemes revealed very little surface exposure of treponemal proteins, although a protein which co-migrated with host albumin was labelled and appeared to be associated with the treponemal surface. Many treponemal proteins were, however, labelled when iodination was done in the presence of Triton. These observations indicate that the outer membrane of T. pallidum differs significantly from those of many Gram-negative pathogens.
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- Physiology And Growth
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The Metabolism of 5'-Methylthioadenosine and 5-Methylthioribose 1-Phosphate in Saccharomyces cerevisiae
More LessSummary: Cordycepin sensitive mutants of Saccharomyces cerevisiae, which are permeable to 5'-deoxy-5'-methylthioadenosine (MTA), were used to study the fate of the methylthioribose carbons of this purine nucleoside. Evidence is presented for the recycling of the methylthio group and part of the ribose portion of MTA in a biosynthetic pathway which leads to the synthesis of methionine. The main pathway involves the phosphorylytic cleavage of MTA by MTA phosphorylase yielding 5-methylthioribose 1-phosphate and adenine as products. Loss of the phosphate group of 5-methylthioribose 1-phosphate, concurrent with the rearrangement of the ribose carbons, leads to the synthesis of 2-keto-4-methylthiobutyric acid. In the final step of the sequence, 2-keto-4-methylthiobutyric acid is converted to methionine via transamination. Several compounds not directly associated with the biosynthesis of methionine were also isolated. These compounds, which may arise through the degradation of intermediates in the pathway, were: 5'-methylthioinosine, a deaminated catabolite of MTA; 5-methylthioribose, a result of the phosphorylysis of 5-methylthioribose 1-phosphate, and 3-methylthiopropionaldehyde, 3-methylthiopropionic acid and 2-hydroxy-4-methylthiobutyric acid, all arising from the catabolism of 2-keto-4-methylthiobutyric acid.
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Growth of Anaerobic Rumen Fungi on Defined and Semi-defined Media Lacking Rumen Fluid
More LessSummary: Anaerobic fungi were isolated from rumen digesta of sheep and cattle and were purified using a plate culture technique. The isolates were successfully cultured on a semi-defined medium which lacked rumen fluid, and on a defined medium.
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- Systematics
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The Mycolic Acids of Mycobacterium chitae
More LessSummary: Two-dimensional thin-layer chromatography of whole-organism acid methanolysates of Mycobacterium chitae gives a characteristic pattern composed of a α-mycolate, a lower molecular weight α '-mycolate and characteristic pairs of polar mycolates. Analysis of alkaline methanolysates confirmed that these polar mycolates were derived from epoxymycolic acids. This pattern of mycolic acids has only been found previously in representatives of Mycobacteriumfarcinogenes, Mycobacteriumfortuitum, ‘Mycobacterium peregrinum’, Mycobacterium senegalense and Mycobacterium smegmatis
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- Short Communications
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Properties of Wild-type Strains of Enterotoxigenic Escherichia coli Which Produce Colonization Factor Antigen II, and Belong to Serogroups Other Than O6
More LessSummary: Enterotoxigenic strains of Escherichia coli, which belonged to serogroups other than O6 and produced colonization factor antigen II, usually produced only coli surface antigen 3 (CS3) and gave weak mannose-resistant haemagglutination of bovine erythrocytes. A non-autotransfer-ring plasmid, NTP165, from a strain of E. coli O168.H16 coded for heat-stable enterotoxin, heat-labile enterotoxin and CS antigens. The CS antigens expressed after acquisition of plasmid NTP165 depended on the recipient strain: a biotype A strain of serotype O6. H 16 expressed CS1 and CS3; a biotype C strain of serotype O6. H16 expressed CS2 and CS3; strain K12 and strain E19446 of serotype O139. H28 expressed only CS3. An exceptional wild-type strain, E24377, of serotype O139. H28 produced CS1 and CS3 when isolated; a variant of E24377 which had lost the plasmid coding for CS antigens produced both CS1 and CS3 after the introduction of NTP165.
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A Method for the Examination of the Substrate Mycelium of Actinomycetes by Scanning Electron Microscopy
More LessSummary: The polyol gel Lutrol FC127 was used to solidify culture media. This gel liquefies as the temperature drops below a critical value for the concentration used. This property was used to recover whole colonies of Thermoactinomyces sp. for examination of the substrate mycelium by scanning electron microscopy.
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Immunoelectronmicroscopic Localization of Calvin Cycle Enzymes in Chlorogloeopsis fritschii
More LessSummary: Antisera against the Calvin cycle enzymes d-ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and phosphoribulokinase (PRK) have been used in immunogold electronmicroscopy studies on cell sections of the cyanobacterium Chlorogloeopsis fritschii. RuBisCO antiserum consistently labelled the carboxysomes (polyhedral bodies) and the cytoplasm. PRK antiserum-labelling occurred in the cytoplasm but not in the carboxysomes. The data agree with in vitro enzyme localization studies, and confirm that both enzymes occur in the cytoplasm and that RuBisCO, but not PRK, also occurs in the carboxysomes of C. fritschii.
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Protective Effect of Lipoteichoic Acid from Lactobacillus casei and Lactobacillus fermentum against Pseudomonas aeruginosa in Mice
More LessSummary: Lipoteichoic acid (LTA) from Lactobacillus casei YIT 90 18 or Lactobacillus fermentum YIT 01 59 augmented the resistance of C57BL/6 mice to infection with Pseudomonas aeruginosa, but conferred no resistance to Listeria monocytogenes. It is suggested that LTA was unable to activate macrophages.
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Volume 71 (1972)
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Volume 70 (1972)
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Volume 69 (1971)
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Volume 68 (1971)
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Volume 67 (1971)
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Volume 66 (1971)
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Volume 65 (1971)
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Volume 64 (1970)
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Volume 63 (1970)
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Volume 62 (1970)
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Volume 61 (1970)
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Volume 60 (1970)
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Volume 59 (1969)
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Volume 58 (1969)
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Volume 57 (1969)
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Volume 56 (1969)
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Volume 55 (1969)
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Volume 54 (1968)
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Volume 53 (1968)
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Volume 52 (1968)
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Volume 51 (1968)
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Volume 50 (1968)
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Volume 49 (1967)
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Volume 48 (1967)
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Volume 47 (1967)
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Volume 46 (1967)
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Volume 45 (1966)
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Volume 44 (1966)
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Volume 43 (1966)
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Volume 42 (1966)
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Volume 41 (1965)
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Volume 40 (1965)
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Volume 39 (1965)
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Volume 38 (1965)
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Volume 37 (1964)
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Volume 36 (1964)
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Volume 35 (1964)
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Volume 34 (1964)
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Volume 33 (1963)
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Volume 32 (1963)
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Volume 31 (1963)
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Volume 30 (1963)
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Volume 29 (1962)
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Volume 28 (1962)
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Volume 27 (1962)
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Volume 26 (1961)
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Volume 25 (1961)
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Volume 24 (1961)
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Volume 23 (1960)
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Volume 22 (1960)
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Volume 21 (1959)
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Volume 20 (1959)
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Volume 19 (1958)
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Volume 18 (1958)
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Volume 17 (1957)
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Volume 16 (1957)
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Volume 15 (1956)
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Volume 14 (1956)
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Volume 13 (1955)
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Volume 12 (1955)
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Volume 11 (1954)
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Volume 10 (1954)
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Volume 9 (1953)
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Volume 8 (1953)
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Volume 7 (1952)
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Volume 6 (1952)
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Volume 5 (1951)
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Volume 4 (1950)
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Volume 3 (1949)
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Volume 2 (1948)
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Volume 1 (1947)