- Volume 131, Issue 11, 1985
Volume 131, Issue 11, 1985
- Biochemistry
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Characterization of Certain Proteinase Isoenzymes Produced by Benign and Virulent Strains of Bacteroides nodosus
More LessThree proteinase isoenzymes from one benign strain of Bacteroides nodosus and five proteinase isoenzymes from each of two virulent strains of B. nodosus were purified by horizontal slab polyacrylamide gel electrophoresis. The purified isoenzymes hydrolysed casein, collagen I, collagen III, elastin, a-elastin, fibrinogen, gelatin, haemoglobin and a-keratin. The pH optima of all the isoenzymes lay between 7.25 and 9.5, the range of 8.75–9.25 being common to all. The isoenzymes were inhibited by phenylmethylsulphonyl fluoride, diphenylcarbamyl chloride, l-(l-tosylamide-2-phenyl)ethyl chloromethyl ketone, EGTA and EDTA, indicating that they were chymotrypsin-like serine proteinases that require a metal ion for stability or activity. EDTA inhibition was not reversed by addition of Ca2+ or Mg2+. Some isoenzymes were activated by Mg2+, Ca2+, Cr3+ and Se4+ and all were inhibited by Fe2+, Co2+, Cu2+, Zn2+, Cd2+ and Hg2+. Isoenzymes from benign strains had a lower temperature stability, losing all activity at 55 °C, whereas those from virulent strains lost all activity at 60 °C.
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The Mechanism of Resistance to Puromycin and to the Puromycin-precursor O-Demethyl-puromycin in Streptomyces alboniger
More LessSummary: Ribosomes from Streptomyces alboniger are sensitive in vitro to puromycin and, to a lesser extent, to the puromycin-precursor O-demethyl-puromycin. The puromycin-inactivating enzyme (puromycin N-acetyltransferase) from S. alboniger also N-acetylates O-demethyl-puromycin. This finding indicates that in certain antibiotic-producing organisms the antibiotic-inactivating enzymes may play a role in self-defence against toxic precursor molecules.
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Mannitol Metabolism in Agaricus bisporus: Purification and Properties of Mannitol Dehydrogenase
More LessSummary: Mannitol dehydrogenase (EC 1.1.1.138) has been purified to homogeneity from fruit bodies of Agaricus bisporus. M r values of 115000 were determined by gel filtration and 130000 by rate zonal ultracentrifugation. The sedimentation coefficient is 6.5S. The native protein is composed of four subunits of M r 29000. The enzyme is specific for NADP, and shows low activity with sorbitol. Normal Michaelis-Menten kinetics are exhibited for both mannitol and NADP, giving K m values of 16.2 mm and 36μm respectively at pH 7.0. The K m value for NADPH is 38.5μm and that for fructose approximately 1.2 m. The V max is 591 μm min−1 (mg protein)−1 for mannitol synthesis and 5μmol min−1 (mg protein)−1 for fructose synthesis at pH 7.0. Inhibition of fructose synthesis by NADPH is stronger than inhibition of mannitol synthesis by NADP. The results are discussed with respect to the control of enzyme activity under physiological conditions.
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Derepression of Enzyme Synthesis in Response to Arginine Limitation in Neurospora crassa
More LessSummary: Ornithine carbamoyltransferase and argininosuccinase, two enzymes involved in arginine synthesis, are regulated by cross-pathway amino acid control in Neurospora and show derepression in response to limitation of any one of a number of amino acids. The effects of varying the severity of arginine limitation upon the synthesis of these enzymes, in mycelial cultures of an arginine auxotrophic strain, are reported here. Derepression occurred at arginine concentrations sufficient to allow normal rates of protein accumulation, leading to increases of not more than fourfold in the absolute rate of enzyme synthesis. On the other hand, differential rates of enzyme synthesis increased progressively up to 20-fold or more under extreme conditions of arginine limitation that also limit net protein synthesis. The major part of the derepression response thus occurred at arginine concentrations that allowed low net rates of protein synthesis. The physiological significance of this is not yet understood. Our evidence suggests that these responses were mediated entirely through the cross-pathway control system, and may not be untypical (allowing for variations in magnitude) of derepression resulting through this mechanism in Neurospora.
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Purification and Characterization of the Secondary Alcohol Dehydrogenase from Propane-utilizing Mycobacterium vaccae Strain JOB-5
More LessSummary: Mycobacterium vaccae strain JOB-5 cultured in the presence of propane contained an inducible secondary alcohol dehydrogenase. The enzyme was purified 198-fold using DEAE-cellulose, ω-aminopentyl agarose and NAD-agarose chromatography. The Mr of the enzyme was approximately 136000, with subunits of Mr 37000. The pH optimum for the reaction oxidizing propan-2-ol to propanone was 10–10.5 while the optimum for the reverse reaction was 7.5–8.5. The isoelectric point was 4.9. NAD but not NADP could serve as electron acceptor. The apparent K m values for propan-2-ol and NAD were 4.9 × 10−5M and 2.8 × 10−4 M, respectively. The enzyme was inhibited by thiol reagents and metal chelators. It appears to play an essential role in the metabolism of propane by this bacterium.
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Energy-dispersive X-ray Microanalysis of Membrane-associated Inclusions in Hydrogenosomes Isolated from Trichomonas vaginalis
More LessSummary: Energy-dispersive X-ray microprobe analysis of electron-dense inclusions in hydrogenosomes isolated from the aerotolerant anaerobic protozoal human parasite Trichomonas vaginalis, Bushby strain, indicated the presence of high levels of Mg, P and Ca. This suggested that divalent cation (e.g. Ca2+ or Mg2+) accumulation by hydrogenosomes may be important in the regulation of intracellular ion concentrations.
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Isolation, Characterization and Topographical Relationships of Pigment-protein Complexes from Membranes of Rhodomicrobium vannielii
D. J. KellY and C. S. DowSummary: Pigment–protein complexes from Rhodomicrobium vannielii were prepared by detergent solubilization of intra-cytoplasmic membranes followed by gel electrophoresis or sucrose gradient centrifugation. These procedures gave rise to two native pigmented complexes. The major one (designated B800-865) was associated with two polypeptides of M r 11000 and 13000 and was identified with the ‘accessory’ light-harvesting complex II found in other members of the Rhodospirillaceae. The minor complex (designated B885-RC) contained both reaction centre and light-harvesting bacteriochlorophyll. Detergent fractionation and reversible chemical cross-linking, followed by two-dimensional polyacrylamide gel electrophoresis, indicated a specific relationship between a membrane-bound cytochrome c-553 and the M r 31000 subunit of the reaction centre.
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- Biotechnology
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Isolation and Culture of a Thermophilic Fungus, Melanocarpus albomyces, and Factors Influencing the Production and Activity of Xylanase
More LessSummary: An uncommon thermophilic fungus, Melanocarpus albomyces, was isolated from soil and compost by incubating samples in a glucose/sorbose/asparagine liquid medium, followed by enrichment culture in medium containing sugarcane bagasse as carbon source. The culture filtrate protein of the fungus grown in the presence of bagasse or xylose hydrolysed xylan and some other polysaccharides but cellulose was not hydrolysed. High extracellular xylanase (EC 3.2.1.8) activity was produced by cultures grown on xylose or hemicellulosic materials. The enzyme was induced in glucose-grown washed mycelia in response to addition of xylose or xylan but not by alkyl or aryl β-d-xylosides. Cultures produced higher enzyme yields in shaken flasks than in a fermenter. Gel-filtration chromatography of culture filtrate protein showed the presence of two isoenzymes of xylanase, whose relative proportions varied with the carbon source used for growth. The extent of hydrolysis of heteroxylans or the hemicellulosic fraction of bagasse by culture filtrate protein preparations was greater when the cultures had been grown on bagasse rather than xylose as the inducing substrate. The activity of xylanase preparations was increased when an exogenous β-glucosidase was added.
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Formulation of Culture Media for Conductimetric Assays: Theoretical Considerations
More LessSummary: The basic theory of electrolytic conductivity in solutions is described and a model is proposed which allows the direction and relative rates of change of conductivity in microbial cultures to be predicted. Guidelines are presented to enable nutrients to be selected so as to maximize conductivity changes. It is shown that a major consideration in any strategy to maximize conductivity changes in cultures must be to direct as many metabolic activities as possible to act in concert in the production or consumption of protons, and to combine this with use of a pH buffer that exhibits a large change in conductivity on taking up or losing a proton. The ability to predict conductivity changes in microbial systems should permit the rational design of culture media for the selective enumeration of microbes by conductimetric methods and the development of other kinds of conductimetric assays.
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- Ecology
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Competition between Rhizobium trifolii Strains for Nodulation, during Growth in a Fermenter, and in Soil-based Inoculants, Studied by ELISA
More LessSummary: An improved ELISA technique using a new type of enzyme-conjugate - the antibody being linked to β-galactosidase by using a heterobifunctional reagent, N-succinimidyl-3-(2-pyridy1dithio)propionate (SPDP), containing two reactive groups directed towards different functional sites - has been further improved by fine purification of the antibodies. The ELISA was applied in studies of competition among strains of Rhizobium trifolii in three environments: a rhizosphere, a liquid medium and in soil. The strain origin of nodules formed by strain mixtures of different relative composition was investigated, including a study of double strain occupancy. Strain 7612 was found to compete successfully with strain 285 for nodulation. No double strain occupancy occurred. Strain 7612 also competed successfully with strain 285 in soil, but strain 285 dominated when grown together with strain 7612 in a liquid medium in a fermenter.
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Calorimetric Studies of Soil Microbes: Quantitative Relation between Heat Evolution during Microbial Degradation of Glucose and Changes in Microbial Activity in Soil
More LessSummary: Heat evolution during the microbial degradation of glucose in a brown arid andosol soil was studied in a conduction-type calorimeter at 30°C. Reproducibilities of the degradation thermograms in terms of the peak time of thermograms, their peak heights, and the total heat evolution, were within ±0.17%, ±1.1% and ±0·51%, respectively (percentage errors). Changes in the number of viable microbial cells and in the amount of glucose degraded revealed linear relationships both between heat evolution and the amount of glucose degraded, and between heat evolution and the viable cell counts, with correlation factors of 0·987 and 0·968, respectively. The heat evolution per unit glucose was α = 1287 ± 52 kJ (mol glucose)−1. The average heat effect per unit cell was q = 6.7 pW per cell, consistent with values determined for bacterial cells in pure culture. On the basis of these results, we propose a method to evaluate the rate of microbial degradation of organic substances in soil. The apparent rate constant (k d) for microbial degradation of glucose in the soil studied was 0·302 ± 0·002 h−1 at 30°C.
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- Genetics And Molecular Biology
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Mutants of Saccharomyces cerevisiae Partially Defective in the Last Steps of the Haem Biosynthetic Pathway: Isolation and Genetical Characterization
More LessSummary: A novel method for the isolation of Saccharomyces cerevisiae mutants partially defective in haem synthesis is described. Mutant clones were identified by their fluorescence under UV light due to the accumulation of porphyrins in cells, and by their ability to grow on nonfermentable carbon sources due to their preserved haemoprotein synthesis. Thirteen such mutants were obtained by this procedure. The defects in haem synthesis and accumulation of porphyrins in all the mutants were confirmed by spectrophotometric analysis. Complementation tests with biochemically defined, haem-less strains showed that in seven mutants uroporphyrinogen decarboxylase was affected and that in three mutants the defect concerned ferrochelatase. The defects in the remaining three mutants were not defined.
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Evidence for the Presence of cAMP, cAMP Receptor and Transcription Termination Factor Rho in Different Gram-negative Bacteria
More LessSummary: Cyclic AMP has been shown to be present in 12 different Gram-negative bacteria and the regulation of its concentration, as a function of growth conditions, is similar to that described for Escherichia coli K12. Antibodies raised against catabolite activator protein (CAP) and Rho protein of E. coli K12 were used to check for the occurrence of cross-reactive antigens. Using radioimmunological assays, immunoblotting techniques and biochemical criteria we showed a wide distribution of CAP and Rho, structurally and functionally closely related to the corresponding E. coli K12 proteins. These results suggest that transcription is similarly regulated by these factors in Gram-negative bacteria.
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The Use of pNJ5000 as an Intermediate Vector for the Genetic Manipulation of Agrobacterium Ti-plasmids
Summary: The use of broad-host-range plasmids derived from RP4 as intermediate vectors for the transfer of narrow-host-range recombinant plasmids from Escherichia coli to Agrobacterium tumefaciens as a preliminary to marker exchange is described. Recombinant plasmids having a ColEl type origin were linked to the RP4 derivative. Cointegrate formation appeared to take place by RecA-independent, homologous recombination within a short piece of DNA derived from the β-lactamase gene of TnllTn3 carried by both vector components, so that it never disrupted the recombinant portion of the construction. pNJ5000 provides an unstable intermediate vector for use in marker exchange experiments, while its stable relative pNJ1020 provides a carrier for use in binary vector systems.
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The Fumarase Genes of Escherichia coli: Location of the fumB Gene and Discovery of a New Gene (fumC)
More LessSummary: The fumB gene of Escherichia coli, which complements the fumarase deficiency of a fumA mutant when present in multiple copies, has been located at 93.5 min in the E. coli linkage map and its product has been identified as a polypeptide of 61 kDal. Four overlapping ColEl-fumB + plasmids representing a continuous segment of 23.3 kb of bacterial DNA have been isolated from the Clarke-Carbon E. coli gene bank and the location of the fumB gene relative to the restriction map and the adjacent mel operon has been defined. Hybridization studies have shown that the fumBB gene is homologous to the fumA gene, which complements the fumAl mutation in single and multi-copy situations, and encodes an analogous 61 kDal product formerly regarded as the E. coli fumarase. The hybridization studies also showed that the Bacillus subtilis fumarase gene (citG) is homologous to an independent gene, fumC (formerly g48), which lies adjacent to the fumA gene at 35·5 min in the E. coli linkage map. The N-terminal sequences of the citG and fumC products exhibit a 51% identity over 88 residues. It is possible that the fumC and citG genes are fumarase structural genes of E. coli and B. subtilis, and that the fumA gene may encode a differentially-regulated fumarase or be a positive regulator gene which is essential for the expression of fumC (but not citG). If so, the fumB gene may encode a related enzyme or activator that can replace the fumA function when amplified.
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Characterization of a Conjugative Plasmid From Erwinia stewartii
More LessSummary:pDC250 is a 52 kb conjugative cryptic plasmid from Erwinia stewartii strain SW2. This plasmid and its transposon-carrying derivatives, pDC251 and pDC252, were transmissible to E. chrysanthemi, E. amylovora, E. milletiae, E. herbicola, Escherichia coli, Shigella flexneri and Salmonella arizonae. In Esch. coli, E.stewartii and E. chrysanthemi, pDC251 was stable and derepressed for conjugal transfer. Hybridization studies confirmed thatpDC250 is widely distributed among E.stewartii strains and showed that it was also closely related to 34 kb plasmids found in strains lacking a 52kb plasmid. The 34 kb plasmid from E.stewartii strain SSI04, pDC140, was transformed into Esch. coli and compared with pDC250. Restriction mapping of the twoplasmids revealed a nearly identical 20 kb region. In Esch.coli, pDC140 was unstable in the presence of pDC250.
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Isolation of Avirulent Mutants of Erwinia stewartii Using Bacteriophage
More LessSummary: Bacteriophage Mu pf7701, a KmR derivative of Mu cts62, was inserted into the conjugative Erwinia stewartii plasmid pDC251, which carries Tn10. When pDC251 : : Mu pf7701 plasmids were conjugated from Escherichia coli into derivatives of E. stewartii strain SS104 they were unstable; loss of either or both drug resistance markers occurred. Stable transconjugants resulted from deletion of Mu sequences, integration of the plasmid into the chromosome, or loss of an indigenous 34 kb cryptic plasmid. Among transconjugants selected for KmR, the largest colonies arose from transconjugants in which Mu pf7701 had transposed to the chromosome and the pDC251 : : Mu pf7701 plasmid had been lost; 1300 transconjugants of this type were screened for pathogenicity to corn (Zea mays) seedlings and eight mutants were obtained that did not cause watersoaking symptoms. The insertions of Mu pf7701 in these mutants were in the chromosome.
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Genetic Mapping of the Rhodopseudomonas capsulata Chromosome Shows Non-clustering of Genes Involved in Nitrogen Fixation
More LessSummary: The mutant R plasmid pTH10 was used to construct a circular linkage map of the Rhodopseudomonas capsulata B10 chromosome. Mutations affecting nitrogen fixation (nif mutations) were dispersed in several groups on the chromosome. Biochemical analysis of nif mutants allowed identification of the structural gene for the nitrogenase component II or Fe protein (nifH) and a putative regulatory gene, possibly nif A. These two genes appeared closely linked in conjugation experiments, but represented two distinct linkage groups in crosses mediated by gene transfer agent. Other mutants were affected in the synthesis and/or stability of the nitrogenase component I or MoFe protein; synthesis of component II was also affected, but to a lesser extent. In two of these mutants, nitrogenase activity and the content of component I was increased five to sixfold by the addition of 1 mm-molybdate to the growth medium.
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- Immunology
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Immunocytochemical Localization of Thioredoxins in the Cyanobacteria Anabaena cylindrica and Anabaena variabilis
More LessSummary: Colloidal gold conjugated goat anti-rabbit IgG and specific antisera raised against purified thioredoxins from Anabaena cylindrica and Anabaena variabilis have been used to determine the localization of thioredoxin in whole filaments of A. cylindrica and A. variabilis. Vegetative cells of A. cylindrica were labelled differently when tested with either of the two anti-thioredoxin sera. The anti-A. cylindrica thioredoxin serum reacted only with A. cylindrica thioredoxin which was located predominantly in the nucleoplasm in vegetative cells; it showed no association with the chromatoplasm. Anti-A. variabilis thioredoxin serum labelled vegetative cells of A. variabilis, particularly in the vicinity of the thylakoid membranes and also labelled A. cylindrica in the vicinity of the thylakoid membranes, indicating that a second thioredoxin or thioredoxin-like protein was present in this cyanobacterium. Heterocysts of A. cylindrica and A. variabilis showed substantially less labelling than vegetative cells when tested with both antisera.
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- Pathogenicity And Medical Microbiology
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F41 Antigen as a Virulence Factor in the Infant Mouse Model of Escherichia coli Diarrhoea
More LessSummary: The properties responsible for the virulence in infant mice of the bovine enterotoxigenic Escherichia coli strain B41 were investigated. A B41K99− variant previously found to be nearly as virulent as the original strain B41 (B41 K99+) possessed F41 antigen and haemagglutinating properties. Two variants that did not haemagglutinate sheep and human erythrocytes were isolated from strain B41K99−. These variants simultaneously lost their ability to agglutinate with F41 antiserum and their haemagglutinating properties. They still produced heat-stable enterotoxin. The first B41K99−F41− variant was much less virulent than strains B41K99+ and B41K99−, the second was not virulent at all. F41 properties were not acquired by other E. coli strains by plasmid transfers. Non-haemagglutinating variants could not be obtained from the original strain B41K99+. However, a B41K99+F41− strain was obtained by a four-step procedure: (i) spontaneous loss of the K99 plasmid, (ii) obtaining a nalidixic acid-resistant mutant, (iii) obtaining a non-haemagglutinating F41− variant, (iv) reacquisition of the K99 plasmid. This B41NalrK99+F41− strain, although producing heat-stable toxin, was not at all virulent, whereas reacquisition of the K99 plasmid by the strain B41NalrF41+ restored virulence. These results show that F41 antigen is an important virulence factor of strain B41 in the infant mouse model.
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Cloning of Genes Determining the Production of Vero Cytotoxin by Escherichia coli
More LessSummary: Sequences encoding the production of a cytotoxin (VT) active on Vero cells were cloned in Escherichia coli K12 from a VT-determining phage that originated in E. coli strain H19 of serotype O26. H11. Subcloning resulted in the identification of a 2.5 kb fragment that still coded for VT production. Mutagenesis with transposon Tn1000 was used to map VT sequences and a 0.75 kb probe was developed. In colony hybridization tests with strains isolated from patients with haemolytic uraemic syndrome or diarrhoea, this probe derived from the H19 VT genes detected only some of the VT+ strains belonging to serogroup O157. A VT+ strain, E32511, serotype O157.H−, which was negative in colony hybridization was the source of another VT-determining phage from which VT sequences were cloned. Southern hybridization of the VT genes from E32511 with the H19 probe was negative under stringent conditions but there was weak homology under conditions of low stringency. These results indicate that there are differences in the VT genes of pathogenic E. coli.
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- Physiology And Growth
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Akinetes of the Cyanobacterium Nostoc PCC 7524: Macromolecular and Biochemical Changes during Synchronous Germination
More LessSummary: Akinetes of Nostoc PCC 7524 germinated synchronously when diluted into fresh medium in the light in the absence of a source of combined nitrogen. The akinetes and their daughter cells were unable to fix N2 until the first heterocysts differentiated in the young three-celled filaments after 19 h. The large glycogen reserves of the mature akinetes were not necessary for germination, since fixation of CO2 commenced immediately and 70% of the fixed carbon accumulated as glycogen. Although cyanophycin was degraded after 6 h, this reserve material was subsequently resynthesized with concomitant breakdown of phycocyanin. These nitrogen reserves were not required for protein synthesis, which was initiated immediately after the induction of germination, apparently at the expense of another, non-proteinaceous, reserve material. Although RNA synthesis occurred without lag, DNA synthesis commenced only after 80 min. Quantitatively similar changes were observed during germination in the presence of combined nitrogen except that neither cyanophycin nor phycocyanin were degraded and balanced growth was achieved more rapidly.
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Salt, pH and Temperature Dependencies of Growth and Bioluminescence of Three Species of Luminous Bacteria Analysed on Gradient Plates
More LessSummary: Two-dimensional diffusion gradients (of NaCl and H+ concentrations) were established in solid growth medium containing glycerol and yeast extract as major carbon sources. These were used to investigate conditions favourable for growth and bioluminescence of three species of luminous bacteria during incubation at different temperatures. Photobacterium leiognathi, Photobacterium phosphoreum and Vibrio fischeri all grew over the entire salt range used [0.9–3% (w/v) NaCl] and at pH values < 7 at the most favourable temperatures (20 °C, 20 °C and 15 °C respectively); upper and lower temperature limits for growth over a 72 h period were 30 and 10, 25 and 5, and 30 and 5 °C respectively. Bioluminescence was observed at all temperatures that supported growth; in P. leiognathi emission at 10 °C was hardly detectable even after 72 h, but at higher temperatures it occurred at all NaCl concentrations. Low pH values and high NaCl concentrations favoured luminescence in the other two organisms; after 48 h light emission decreased from the high pH and low NaCl regions of the gels. These results are discussed with reference to the symbiotic (P. leiognathi, V. fisheri) or free-living (P. phosphoreum) origins of the organisms studied.
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Synchronization of the Cell Division Cycle of Chlamydomonas eugametos
More LessSummary: A description is given of the vegetative growth of Chlamydomonas eugametos in liquid cultures. When a circadian light/dark regime is applied, cell division takes place during the dark periods and the release of the daughter cells is phased round the dark/light transitions. However, as long as the cultures are agitated, only a fraction of the cells divides during any dark period. The mother cells stick firmly to the surface of the culture vessels, making it possible to separate them from the non-dividing cells. They release daughter cells that show cell cycles of 1 × 24 h, 2 × 24 h and longer. Only in static cultures do all cells divide synchronously every 24 h. To explain these results, a correlation is postulated between the chance of settling and the length of the division cycle.
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Autolytic Release of Mannoproteins from Cell Walls of Saccharomyces cerevisiae
More LessSummary: Autolysis of purified Saccharomyces cerevisiae cell walls resulted in the release of several components thought to be mannoprotein in nature, since they were retained by Concanavalin A-Sepharose. The most abundant was a 29 kDal molecule which was also a major species among mannoproteins solubilized by the β-glucanase complex Zymolyase. There was a concomitant release of glucose and mannose oligosaccharides and of β-glucanase activity. Glucanase and protease inhibitory treatments considerably lowered the release of mannoproteins. The use of different protease inhibitors during autolytic incubations interfered with at least two proteases (one of them being a cysteine protease) apparently involved in the solubilization and partial degradation of mannoproteins from the walls.
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- Systematics
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Further Studies on Thymidine Kinase: Distribution Pattern of the Enzyme in Bacteria
More LessSummary: Various micro-organisms (131 strains of 73 species) were studied for their ability to produce thymidine kinase (TK; EC 2.7.1.21). Taking the specific TK activity of Escherichia coli K12 [specific activity of sonicated cell extracts 95–194 pmol min−1 (mg protein)−1] as 100%, the test organisms had the following relative specific TK activities. In the Gram-positive cocci, Staphylococcus aureus (21–84%) showed higher activity than Staph. epidermidis (1–20%) and Streptococcus (1–7%) except for one strain of Strep, pyogenes (29%). Neisseria sicca, a Gram-negative coccus, lacked TK. Gram-positive endospore-forming rods showed significant activity (Bacillus, 13–51%; Clostridium perfringens. 9–18%) except for one strain of B. megaterium (2%) and C. difficile (1–3%). Among the Gram-positive asporogenous rods, Listeria monocytogenes and six species of Lactobacillus (especially L. brevis, L. buchneri and L. casei) had moderate to high activity (23–348%) but L. acidophilus, L. bulgaricus, L. lactis and L. cellobiosus had low activity (0–8%). Of the species of Pseudomonas studied, most lacked TK but Ps. fluorescens and Ps. maltophilia had significant TK activity (15–53%). Of the Gram-negative facultative anaerobes, Vibrio lacked TK, while Enterobacteriaceae, including Salmonella (148–1120%), Escherichia (59–141%), Klebsiella (78–299%) and Serratia (61–110%), had a high activity. Proteus had a somewhat lower activity (0–34%) except for ‘Pr. rettgerella’ (307%). Propionibacterium and Bifidobacterium and related organisms other than Streptomyces, Nocardia, Rhodococcus, Corynebacterium and Mycobacterium lacked TK. The seven species of Candida tested, and Cryptococcus neoformans, essentially lacked TK. The distribution of TK among various bacteria showed some correlation with a phylogenic tree based on 5S rRNA sequences; in particular, organisms with 5S rRNA of the 118N-type did not produce TK.
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Multivariate Analysis of Neisseria DNA Restriction Endonuclease Patterns
More LessSummary: Chromosomal DNA was extracted from eleven Neisseria meningitidis and seven Neisseria gonorrhoeae isolates and cleaved with the restriction enzyme HindIII. The DNA fragments were separated according to their size, using a 4% polyacrylamide gel. The band patterns obtained were digitized and statistically analysed by the SIMCA method. To develop the models for N. meningitidis (class 1) and N. gonorrhoeae (class 2), all eleven meningococci and seven gonococci were used. All strains were classified correctly and showed an extremely good class separation.
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Genetic Relationships among Neisseria Species Assessed by Comparative Enzyme Electrophoresis
More LessSummary: The electrophoretic mobilities of 12 enzymes from 19 Neisseria species (including 6 strains of N. perflava), Gemella haemolysans, Escherichia coli and Branhamella catarrhalis were characterized by polyacrylamide slab gel electrophoresis. All strains and species tested exhibited qualitatively different zymogram patterns. Species and strain relationships were quantified by pairwise comparisons of all 12 enzyme systems to obtain similarity indices; these data were subjected to numerical clustering methods to obtain groups and a phenogram. The electrophoretic classification compared favourably with those obtained by other criteria. In addition, the quantitative clustering data indicated that N. ovis and N. caviae are sufficiently different from the other Neisseria species to warrant their separation into a distinct group. These two species also lacked the characteristic NADPH-diaphorase zymogram pattern found in all the other Neisseria species. Intra-species similarity indices were generally greater than the inter-species index values. However, certain species such as N. meningitidis and N. gonorrhoeae had similarity index values in the range of inter-strain index values.
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Characterization of a Mycoplasma Virus (MV-O1) Derived from and Infecting Acholeplasma oculi
More LessSummary: A new Mycoplasmatales virus, referred to as MV-O1, was isolated during cloning of Acholeplasma oculi 19L. The virus formed plaques only on strains of A. oculi, i.e. the original clone, A. oculi 19L, a subclone of A. oculi 19L (A. oculi-i), A. oculi Goat 5 and a wild isolate (K-2) of A. oculi, but not on other acholeplasmas, including strains of A. laidlawii, nor on five human mycoplasma species tested. The virus required horse serum for multiplication as well as for plaque formation and passed through a 100 nm filter. Electron microscopy revealed enveloped, spherical particles 80-130 nm in diameter. The buoyant density of purified virus was 1.23 g ml−1 in CsCl, and agarose gel electrophoresis indicated that the viral nucleic acid was DNA.
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- Short Communications
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Electron Microscopic Studies of Lipopolysaccharides from Phase I and Phase II Coxiella burnetii
More LessSummary: Lipopolysaccharides from phase I (LPSI) Coxiella burnetii Ohio and Nine Mile strains and from phase II (LPSII) Nine Mile strain were stained negatively and positively and examined with the electron microscope. The ultrastructure of LPSI and LPSII positively stained with uranyl formate or uranyl acetate was ribbon-like. When negatively stained with uranyl acetate, LPSI was ribbon-like but LPSII exhibited hexagonal lattice structures. However, LPSII stained negatively with sodium phosphotungstate and ammonium molybdate exhibited hexagonal lattice ultrastructures which were not identical to those observed when negatively stained with uranyl acetate. The hexagonal lattice structures formed in vitro were due to the interactions of LPSII and the staining reagents rather than to protein-LPS interactions. The differences in the ultrastructures of LPSI and LPSII are undoubtedly based on variations in their chemical composition.
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Pseudospirochaetes in Peritoneal Exudates of Mice Injected with Bacillus aneurinolyticus
More LessBodies initially thought to be spirochaetes were observed in the ascites of mice injected intraperitoneally with Bacillus aneurinolyticus (KA bacillus). Electron microscopy revealed that these bodies were in fact ‘pseudospirochaetes’ originating from the flagellar bundles of the bacilli.
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Detection of Tellurite-resistance Determinants in IncP Plasmids
More LessSummary: Six IncP plasmids were tested for their ability to generate tellurite-resistant variants by plating bacterial strains harbouring them on medium containing potassium tellurite. Four plasmids, three of subgroup IncPα and one not allocated, formed variants that could transfer tellurite-resistance at the same frequency as plasmid-determined drug resistance. This property was not shared by two examples of subgroup IncPβ.
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- Corrigenda
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Acholeplasma laidlawii Cells Acutely and Chronically Infected with Group 1 Acholeplasmavirus
More Lessp. 1714, last paragraph of Methods:
The second sentence should read : ‘Polypeptide profiles of these cell preparations were obtained by SDS-PAGE (Liss & Heiland, 1982), modified by using glass-distilled water instead of 8 m-urea in the formulation of the separating gel and the sample preparation solution’.
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Volumes and issues
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Volume 170 (2024)
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Volume 169 (2023)
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Volume 168 (2022)
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Volume 167 (2021)
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Volume 166 (2020)
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Volume 165 (2019)
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Volume 164 (2018)
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Volume 163 (2017)
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Volume 162 (2016)
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Volume 161 (2015)
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Volume 160 (2014)
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Volume 159 (2013)
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Volume 158 (2012)
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Volume 157 (2011)
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Volume 156 (2010)
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Volume 155 (2009)
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Volume 154 (2008)
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Volume 153 (2007)
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Volume 152 (2006)
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Volume 151 (2005)
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Volume 150 (2004)
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Volume 149 (2003)
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Volume 148 (2002)
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Volume 147 (2001)
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Volume 146 (2000)
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Volume 145 (1999)
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Volume 144 (1998)
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Volume 143 (1997)
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Volume 142 (1996)
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Volume 141 (1995)
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Volume 140 (1994)
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Volume 139 (1993)
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Volume 138 (1992)
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Volume 137 (1991)
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Volume 136 (1990)
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Volume 135 (1989)
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Volume 134 (1988)
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Volume 133 (1987)
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Volume 132 (1986)
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Volume 131 (1985)
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Volume 130 (1984)
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Volume 129 (1983)
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Volume 128 (1982)
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Volume 127 (1981)
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Volume 126 (1981)
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Volume 125 (1981)
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Volume 124 (1981)
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Volume 123 (1981)
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Volume 122 (1981)
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Volume 121 (1980)
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Volume 120 (1980)
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Volume 119 (1980)
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Volume 118 (1980)
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Volume 117 (1980)
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Volume 116 (1980)
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Volume 115 (1979)
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Volume 114 (1979)
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Volume 113 (1979)
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Volume 112 (1979)
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Volume 111 (1979)
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Volume 110 (1979)
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Volume 109 (1978)
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Volume 108 (1978)
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Volume 107 (1978)
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Volume 106 (1978)
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Volume 105 (1978)
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Volume 104 (1978)
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Volume 103 (1977)
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Volume 102 (1977)
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Volume 101 (1977)
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Volume 100 (1977)
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Volume 99 (1977)
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Volume 98 (1977)
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Volume 97 (1976)
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Volume 96 (1976)
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Volume 95 (1976)
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Volume 94 (1976)
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Volume 93 (1976)
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Volume 92 (1976)
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Volume 91 (1975)
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Volume 90 (1975)
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Volume 89 (1975)
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Volume 88 (1975)
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Volume 87 (1975)
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Volume 86 (1975)
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Volume 85 (1974)
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Volume 84 (1974)
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Volume 83 (1974)
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Volume 82 (1974)
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Volume 81 (1974)
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Volume 80 (1974)
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Volume 79 (1973)
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Volume 78 (1973)
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Volume 77 (1973)
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Volume 76 (1973)
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Volume 75 (1973)
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Volume 74 (1973)
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Volume 73 (1972)
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Volume 72 (1972)
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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)