- Volume 132, Issue 11, 1986
Volume 132, Issue 11, 1986
- Biochemistry
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Subdivision of Daughter Strains of Bacille Calmette-Guérin (BCG) According to Secreted Protein Patterns
More LessSUMMARY: In order to identify proteins secreted by live organisms, daughter strains of the Bacillus Calmette-Guérin (BCG) were grown for 4-7 d in a defined medium containing [35S]methionine. Secreted components were then separated by polyacrylamide gel electrophoresis under both denaturing and non-denaturing conditions, and analysed by autoradiography and in an Ambis beta-scanner. The results indicate that BCG daughter strains can be subdivided into two groups according to their secretion of a 46 kDa protein dimer consisting of two similar 23 kDa subunits. High-producer strains (Japanese, Brazilian and Russian) secrete very large quantities of this material, which constitutes approximately 23% of all secreted protein. These findings correlate with earlier studies in which degradation products of the protein dimer may have been identified, and with the data from patterns of cell wall lipids.
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Induction of Methanethiol Production by Brevibacterium linens CNRZ 918
More LessSUMMARY: A non-inducing medium (NID) was defined for studying the induction of methanethiol production by Brevibacterium linens CNRZ 918. The lowest l-methionine concentration capable of inducing maximal methanethiol production by the cells was 7 mM. The peptides l-Ala-l-Met and l-Met-l-Ala induced greater methanethiol production than free l-methionine. D-Methionine, l-cysteine, S-methyl-l-cysteine and l-ethionine were poor inducers. Culture temperature affected the duration of induction. An Na+ concentration of 1 M in the culture medium led to maximal methanethiol production capacity of both cells and cell extracts. l-Methionine and l-ethionine were the best substrates for the crude soluble cells extract (with release of methanethiol and ethanethiol respectively). Neither the derivatives of l-methionine that acted as inducers, nor D-methionine, were substrates for demethiolation. Demethiolation activity of the crude extract was thermolabile, not stimulated by Na+ and strongly inhibited by Zn2+, Mn2+ and Cu2+. The shortest generation time obtained for B. linens CNRZ 918 in NID medium + l-methionine was 4 h at 26 °C. Only coccoid forms were present when the culture temperature was 30 °C. The presence of l-methionine in the medium favoured their appearance. The strain grew best in the presence of 1% NaCl but tolerated concentrations up to 15%. The induction of methanethiol production was due to the induction of l-methionine-γ-demethiolase. The level of induction was probably related to the intracellular concentration of l-methionine. The transport system of l-methionine by B. linens CNRZ 918 was constitutive and Na+ dependent.
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Composition of Lipopolysaccharides from Four Strains of Erwinia amylovora
More LessSUMMARY: The lipopolysaccharides (LPSs) from four isolates of Erwinia amylovora were examined. One isolate was virulent and capsulate, and it produced extracellular polysaccharide (EPS). Three were avirulent, of which one was capsulate and produced EPS; the remainder were non-capsulate and did not produce EPS. LPS was recovered from the cells and from the culture medium. Material extracted from the cells using phenol-water was indistinguishable from LPS extracted with phenol-chloroform-light petroleum. Acid hydrolysis released lipid A which contained in all cases glucosamine, phosphate and the fatty acids 12:0, 14:0 and 3-OH 14:0. The carbohydrate released by mild acid hydrolysis was resolved by gel permeation chromatography into three components: I, a partially included species identified as core substituted with a short sidechain of fucose, galactose and glucose; II, an unsubstituted core oligosaccharide containing heptose, glucose, uronic acid, amino compounds and 3-deoxy-2-octulosonic acid (KDO); III; a totally-included low M r fraction containing KDO, phosphate and amino compounds. The sidechain component was missing from LPS of one of the non-capsulate strains that did not produce EPS. This strain is believed to lack UDP-glucose-4-epimerase, a key enzyme in the biosynthesis of galactose. Galactose (with glucose and uronic acid) is known also to be a component of EPS. Defects in galactose synthesis may therefore affect the assembly of LPS as well as EPS.
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Regulation of the Enzymes of Lysine Biosynthesis in Bacillus sphaericus NCTC 9602 during Vegetative Growth
More LessSUMMARY: Enzymes were assayed in extracts of Bacillus sphaericus harvested late in the exponential phase from batch cultures in a minimal (acetate plus salts) medium. Aspartokinase was repressed and inhibited by threonine; lysine alone had no effect, though it increased the inhibition (but not the repression) by threonine. Aspartic β-semialdehyde dehydrogenase was slightly repressed by lysine. Dihydrodipicolinate synthase was inhibited non-competitively by lysine, and dihydro-dipicolinate reductase was partly repressed by lysine. Diaminopimelate dehydrogenase (with tetrahydrodipicolinate as substrate) was inhibited by meso-diaminopimelate. Lysine did not repress diaminopimelate decarboxylase, and only slightly inhibited this enzyme. An auxotrophic mutant that required threonine and methionine excreted lysine after growth had stopped with a limited concentration of threonine.
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- Ecology
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Evidence for a Weak Active External Adsorption of Azospirillum brasilense Cd to Wheat Roots
More LessSUMMARY: Azospirillum brasilense Cd, when inoculated onto wheat roots, multiplied and formed aggregates on the root surfaces and established an internal root population. Washing the roots removed most of the external but not the internal bacterial population. Killing the bacteria before or after their interaction with the roots eliminated the adsorbed bacteria from the root surface. The external adsorption of A. brasilense to wheat roots can be categorized as a weak active process.
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- Genetics And Molecular Biology
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A General Method for Fusion of the Escherichia coli lacZ Gene to Chromosomal Genes in Bacillus subtilis
More LessSUMMARY: A series of plasmids has been constructed that can be used to fuse the β-galactosidase gene (lacZ) of Escherichia coli to chromosomal genes of Bacillus subtilis. Insertion of the lacZ gene is facilitated by the use of a selectable chloramphenicol acetyl-transferase (cat) gene. The latter is included, along with the lacZ gene, in a single DNA fragment or “cartridge” that can be removed from the plasmid with a variety of different restriction endonucleases. Methods applicable to any cloned B. subtilis gene are described that enable the lac–cat cartridge to be inserted at specific sites, or at random, directly into the B. subtilis chromosome in a single step. These single-copy chromosomal fusions can be readily transferred, by selection for chloramphenicol resistance, to a temperate phage such as ϕ105, to permit a more extensive genetic analysis of the expression of the target gene. Alternatively, the lac–cat cartridge and flanking DNA sequences can be transferred into different genetic backgrounds by transformation. These techniques have been used to construct, in a single step, lac fusions to genes in the sporulation operons spoIIA and spoVA.
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Use of a lacZ Gene Fusion to Determine the Dependence Pattern of Sporulation Operon spoIIA in spo Mutants of Bacillus subtilis
More LessSUMMARY: A spoIIA:: lacZ gene fusion has been used to investigate the dependence pattern of expression of the spoIIA operon during sporulation in Bacillus subtilis. β-Galactosidase activity, encoded by the hybrid gene, begins to appear about 30 to 60 min after the induction of sporulation. spoIIA expression is dependent upon the products of all of the known spoO loci but on none of the “later” loci tested. The β-galactosidase activity falls after 1.5 h in Spo+ cells and in late-blocked mutants, but continued accumulation of the enzyme occurs in certain stage II mutants. Kinetic experiments suggest that the fall in activity may be, in part, the result of regulation at the level of translation. Mutations in several loci, spoOJ, spoIIIF and spoVIC, delay expression of the operon by 1-3 h. The significance of these results in terms of models for the control of gene expression during sporulation is discussed.
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Use of a lacZ Gene Fusion to Determine the Dependence Pattern and the Spore Compartment Expression of Sporulation Operon spoVA in spo Mutants of Bacillus subtilis
More LessSUMMARY: A spoV AA:: lacZ gene fusion has been used to study expression of the spoV A operon during sporulation in Bacillus subtilis. β-Galactosidase activity, encoded by the fusion gene, begins to be produced about 2.5 h after the induction of sporulation, well before the phenotypic consequences of spoV A mutations are manifested. spoV A expression is dependent on all of the known spoO and spoII loci and on some of the “early” spoIII loci, but not on “later” loci. Several lines of evidence suggest that spoV A expression occurs only in the spore compartment. The implications of this observation for models of the overall regulation of gene expression during sporulation are discussed.
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Use of lacZ Gene Fusions to Determine the Dependence Pattern of the Sporulation Gene spoIID in spo Mutants of Bacillus subtilis
More LessSUMMARY: The spoIID gene, which is involved in Bacillus subtilis sporulation, was fused to the β-galactosidase gene, lacZ, of Escherichia coli so that the expression of β-galactosidase would be under the control of the spoIID locus. When the fused product was inserted into the B. subtilis chromosome, production of β-galactosidase indicated that the spoIID gene was expressed 1.5 h after the start of sporulation. When the spoIID:: lacZ fusion was inserted into the chromosome of sporulation mutants, all strains carrying spoO lesions and those with mutations in spoIIA, spoIIE and spoIIG loci failed to make β-galactosidase. The proposed provisional order of expression of operons governing stage II is spoIIA [spoIIG, spoIIE] [spoIID, spoIIB, spoIIF].
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Use of a lacZ Gene Fusion to Determine the Dependence Pattern of Sporulation Operon spoIIIC in spo Mutants of Bacillus subtilis: a Branched Pathway of Expression of Sporulation Operons
More LessSUMMARY: The sporulation gene spoIIIC from Bacillus subtilis was fused to the lacZ gene from Escherichia coli, so that the transcription of the lacZ gene was under the control of the spoIIIC promoter. Production of β-galactosidase, under conditions of sporulation, was then used as an indicator to study the expression of spoIIIC in relation to other sporulation loci. Expression of spoIIIC, which occurred only in the mother cell compartment, was prevented by mutations in all of the stage 0 and stage II loci, and also by spoIIID, spoIV A and spoIV B mutations. By contrast, the last three operons are not needed for expression of spoV A, which has previously been shown to be spore-specific. In consequence, a branched pathway of gene expression is proposed. One branch leads to expression of spoV A within the spore compartment, the other to expression of spoIIIC in the mother cell.
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Synthesis of spoIIA and spoV A mRNA in Bacillus subtilis
More LessSUMMARY: The expression of the spoIIA and spoV A sporulation loci of Bacillus subtilis was examined by using DNA-RNA hybridization to detect the time of appearance of their corresponding mRNA molecules in wild-type and asporogenous mutants of B. subtilis. From the size of the mRNA molecules it is clear that both the spoIIA and spoV A loci are polycistronic operons. Neither of the mRNA molecules is polyadenylated. The results also indicate the spoIIA operon is regulated by two promoters which become functional at different times.
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The Nucleotide Sequence and the Transcription During Sporulation of the gerE Gene of Bacillus subtilis
More LessSUMMARY: We have determined the nucleotide sequence of a 1496 bp stretch of Bacillus subtilis chromosome that complements the gerE36 mutation. The sequence contains three open reading frames. One of these is part of the sdhC gene, the other two, whose functions are unknown, are capable of encoding proteins with M r values of approximately 17000 and 8500. The use of integrational plasmids to delimit the gerE transcriptional unit shows that the gerE locus consists of one gene, which encodes a polypeptide of 74 amino acid residues and which is switched on after t 3 during sporulation of wild-type B. subtilis 168.
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Cloning and Sequencing of a Gene from Bacillus amyloliquefaciens that Complements Mutations of the Sporulation Gene spoIID in Bacillus subtilis
More LessSUMMARY: A segment of DNA from Bacillus amyloliquefaciens, which complemented a mutant sporulation gene, spoIID68, in Bacillus subtilis, was cloned into a derivative of the temperate bacteriophage ϕ105. The segment of DNA included an entire structural gene and complemented the mutation spoIID298, in addition to spoIID68, in B. subtilis.
The nucleotide sequence of the gene from B. amyloliquefaciens was determined and compared with that of the B. subtilis gene; 74% homology was found in the coding region. Amino acid primary sequences derived from the nucleotide sequences of the two genes were also compared. The gene from B. amyloliquefaciens coded for a protein of 344 amino acid residues, one more than the protein coded by the corresponding gene from B. subtilis. Comparison of the primary amino acid sequences of the two genes showed that 78% of the residues were completely conserved and 8% were semi-conserved. Variation, however, was not random, i.e. some segments were much more highly conserved than others. Both proteins had a hydrophobic region at the N-terminus.
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dam Methylation in the Archaebacteria
More LessSUMMARY: The DNA of certain species of halophilic and methanogenic archaebacteria is dam methylated, as shown by restriction endonuclease sensitivities. The Dam+ phenotype appears to be confined to particular taxonomic groupings defined by DNA:rRNA hybridization or 16S RNA oligonucleotide cataloguing.
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Factors Enhancing Genetic Transformation of Intact Yeast Cells Modify Cell Wall Porosity
More LessSUMMARY: Genetic transformation of intact cells of Saccharomyces cerevisiae, achieved by incubating the cells with plasmid DNA in the presence of PEG, could be enhanced, not only by pretreatment of the cells with Li+ and 2-mercaptoethanol, as has been reported previously, but also by pretreatment with proteolytic enzymes. The efficiency of transformation with 2-mercapto-ethanol rose dramatically when the pretreated cells had been handled in osmotically stabilized media. Following all the pretreatments the cells became leaky for nucleic acids as detected by the presence of endogenous RNAs in the medium. The pretreatments evidently facilitated the passage of transforming DNA across the cell wall.
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Mutations Affecting Gluconate Catabolism in Escherichia coli. Genetic Mapping of the Locus for the Thermosensitive Gluconokinase
More LessSUMMARY: An Escherichia coli strain unable to use gluconate was isolated by spontaneous curing of λc1857 s7 xis6 b515 b519, λc1857 s7 Δ(A-att) dargI valS lysogens. Two lesions, linked to asd and pyrB markers, respectively, were necessary to produce this phenotype. The asd-linked mutation gnt-17, of regulatory type, seems to affect the expression of the major system of gluconate utilization (min 75) as well as that of 6-phosphogluconate dehydratase (gene edd, min 41), the first enzyme of the Entner-Doudoroff pathway. A closely linked suppressor of gnt-17 causes constitutivity of these activities; this suppressor resembles gntR, which is also in the asd region. Hence, it is possible that gnt-17 is a super-repressing allele of gntR, rather than a positive controlling element. Lesion gnt-17 alone does not prevent the utilization of gluconate; for this, the mutation gnt-18 at 96.9 min is also necessary. This mutation abolishes the thermosensitive gluconokinase activity and thus eliminates the subsidiary ability to catabolize gluconate. Accordingly, gnt-18 seems to be allelic with gntV, the locus postulated as being in the pyrB region specifying the thermosensitive gluconokinase.
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Complementation of Mutations in Escherichia coli and Bordetella pertussis by B. pertussis DNA Cloned in a Broad-host-range Cosmid Vector
More LessSUMMARY: A gene library of Bordetella pertussis DNA was constructed in Escherichia coli using the broad-host-range cosmid vector pLAFR1. The average insert size was 24-9 kb. From 500 members of the gene library, clones were identified which complemented trpE, glnA and Thr− mutations in E. coli but none which complemented trpD, trpC, trpB, trpA, proA or Leu− mutations. Four clones were identified which complemented trpE in E. coli. Anthranilate synthase activity was detected in a trpE strain only when it harboured a plasmid from one of these clones; activity was repressed when tryptophan was included in the growth medium. Two clones were identified which complemented glnA of E. coli. A recombinant plasmid from one of these clones also restored some of the nitrogen acquisition functions of glnG and glnL in E. coli. Expression of several B. pertussis virulence-associated products (haemolysin, heat-labile toxin, adenylate cyclase, filamentous haemagglutinin, and the cell-envelope polypeptide of M r 30000) was not detected in 500 independent clones. However, by transferring the recombinant plasmids to a mutant of B. pertussis deficient in haemolysin and adenylate cyclase, a plasmid was identified which restored both these activities.
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- Pathogenicity And Medical Microbiology
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Hepatic Lesions in Experimental Campylobacter jejuni Infection of Mice
More LessSUMMARY: Mice orally infected with Campylobacter jejuni developed focal infiltrative necrotic lesions in the liver, as determined by both histology and liver function tests. The initial histopathological feature was a focal infiltrative lesion in the parenchyma and portal triads. Foci of infiltrative lesions became necrotic between days 30 and 60 post-inoculation (p.i.). During this period, portal infiltrates increased in severity. From month 4 p.i., focal areas of infiltrative necrosis in the liver parenchyma became extensive. Study of liver function demonstrated mild elevations of transaminases, alkaline phosphatase and lactic dehydrogenase, and also the presence of hypoalbuminaemia. Although histopathological changes of the liver became gradually more marked after day 30 p.i., liver functions of infected mice were most affected at 2 months p.i. The capacity of C. jejuni to induce hepatic lesions seemed to be related to that of organisms to persist in the gall bladder; there was no correlation between biliary carriage in infected mice and positive faecal culture.
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A Revised Probability Matrix for the Identification of Gram-negative, Aerobic, Rod-shaped, Fermentative Bacteria
More LessSUMMARY: The results of the identification of 933 strains of Gram-negative, aerobic, rod-shaped, fermentative bacteria (Enterobacteriaceae, Pasteurellaceae, Vibrionaceae) by a probabilistic method, in a computer, are given. The identification rate on the matrix was 89.2%. Many of the strains were atypical and had caused difficulty in identification in medical diagnostic laboratories. The results are given for each taxon by genus and species.
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- Physiology And Growth
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Temporal Changes in the Pattern of Intra-cytoplasmic Membrane Protein Synthesis during the Swarmer Cell Cycle of Rhodomicrobium vannielii
More LessSUMMARY: Swarmer cells and multicellular arrays of Rhodomicrobium vannielli synthesized different types of intra-cytoplasmic membrane proteins, as evidenced by pulse-labelling patterns with [35S]methionine. Analysis of protein synthesis during the swarmer cell cycle revealed temporal changes in the rates of synthesis of several proteins, including those of the light-harvesting complex I (B885)-reaction centre pigment-protein complex and a 34000 M r protein identified as flagellin. The results are discussed in terms of differentiation and polar growth in this and related members of the Rhodospirillaceae.
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Effect of Halocin H4 on Cells of Halobacterium halobium
More LessSUMMARY: The killing of a population of a sensitive strain of Halobacterium halobium by halocin H4 followed exponential kinetics, and the percentage survival of sensitive cells exposed to different concentrations of halocin H4 corresponded to single-hit-type kinetics. Morphological changes were observed in treated cells, which showed swollen, spherical shapes. Halocin H4 affected macromolecule synthesis very little, and only late after the start of the treatment, although the transport of 2-aminoisobutyric acid, a non-metabolizable amino acid, was rapidly stopped. Bacteriorhodopsin-mediated H+ extrusion worked very efficiently in treated cells, and much larger pH decreases were found in treated than in untreated suspensions after illumination, although ATP synthesis was not markedly affected. These findings suggest that the primary target of halocin H4 may be located in the membrane, producing permeability changes and ionic imbalance, which lead to death and cell lysis.
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Development of Candida albicans Hyphae in Different Growth Media-Variations in Growth Rates, Cell Dimensions and Timing of Morphogenetic Events
More LessSUMMARY: In six liquid culture media, all of which stimulated Candida albicans to grow in the hyphal form, the rates of hyphal extension and increase in cellular ATP concentration, hyphal diameters, times of evagination of hyphae, times of septum formation and positions of septa in the hyphae appeared to vary independently. There were no discernible associations between properties such as length or volume of hyphal compartments at the time of septation and temporal parameters of hyphal growth. The results suggest that growth environment influences many of the processes contributing to hyphal development, but that these processes are not necessarily interrelated.
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Structure, Distribution and Function of Wax Esters in Acinetobacter calcoaceticus
More LessSUMMARY: The wax esters of Acinetobacter calcoaceticus strains NCIB 8250 and NCIB 10487 harvested at stationary phase from N-limited batch cultures were extracted and shown to consist of C14 to C18 saturated and mono-unsaturated alkan-l-ols randomly esterified with C14 to C18 saturated and mono-unsaturated fatty acids. The mono-unsaturated components contained a cis Δ9 double bond. Wax ester content of strain NCIB 8250 increased under conditions of low growth rate in N-limited continuous culture with carbon and energy source in excess. The high content of wax ester in N-limited cultures of strain NCIB 8250 was lowered by incubation in the absence of a carbon and energy source and the wax ester was converted to water-soluble materials and CO2. It is proposed that in A. calcoaceticus NCIB 8250 the endogenous wax ester present in N-limited cells can serve as an energy reserve. All 19 strains of A. calcoaceticus tested contained some wax ester and as 16 of these strains had increased wax ester contents when harvested from stationary phase N-limited batch cultures, it appears that wax esters are widespread, but not universal, energy storage components in the genus Acinetobacter.
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Isocitrate Lyase Activity in Thiobacillus versutus Grown Anaerobically on Acetate and Nitrate
More LessSUMMARY: In cell-free extracts of Thiobacillus versutus, an organism which has been reported to be isocitrate lyase negative, an isocitrate lyase activity of 52 ± 18 nmol min−1 (mg protein)−1 was observed after anaerobic growth in a chemostat on acetate plus nitrate, i.e. during denitrification. Following growth on succinate plus nitrate, isocitrate lyase activity was only 1 ± 2 nmol min−1 (mg protein)−1. In cell-free extracts derived from aerobic chemostat cultures isocitrate lyase activity was always nil. The identity of the enzyme was analysed using a number of different methods, namely (a) three different enzyme assays, (b) 13C-NMR spectroscopy of the reaction products, (c) HPLC analysis of the reaction products, (d) mass spectrometry of derivatized glyoxylate enzymically produced from isocitrate and (e) radiography of derivatized glyoxylate enzymically produced from [14C]citrate. All these methods gave results consistent with the enzyme-catalysed conversion of isocitrate to glyoxylate and succinate.
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The Phosphonium Ion Efflux System of Escherichia coli: Relationship to the Ethidium Efflux System and Energetic Studies
More LessSUMMARY: The extent of accumulation of methyltriphenylphosphonium ion by Escherichia coli was shown to be dependent on the permeability of the outer membrane and the activity of an efflux system for this compound. Evidence consistent with the operation of a single efflux system for compounds such as phosphonium ions, phenanthridiniums and flavines is presented. Studies on the energy coupling mechanism for this efflux system indicated that it was driven by the transmembrane proton electrochemical gradient.
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Light-modulated Antennae Acclimation in the Cyanobacterium Anacystis nidulans: Effects of Transcriptional and Translational Inhibitors
More LessSUMMARY: The effect of transcriptional and translational inhibitors on growth and on the light acclimation of the photosynthesis antennae of Anacystis nidulans was examined after a shift from white incandescent light (300 μE s−1 m−2) to red light (15 μE s−1 m−2). Addition of antibiotics that inhibit transcription (rifampicin) or translation (streptomycin, chloramphenicol and kanamycin) immediately blocked cell growth, and RNA and protein synthesis, when added either early or later after the light shift. The ratio of phycocyanin to chlorophyll a stayed constant. Addition of the antibiotics shortly after the shift also immediately blocked the increase in the ratios of phycocyanin and chlorophyll a to cell mass, whereas later addition resulted in decreases of about 50% and 12 to 30% in these ratios with rifampicin and streptomycin, respectively. No changes in pigment content were found when the antibiotics were added during steady state conditions with white or red light. The results show that both phycocyanin and chlorophyll a light acclimations are immediately and completely blocked by the addition of both transcriptional and translational inhibitors. We also propose that the light antennae may exist in an unstable form in the course of the acclimation process.
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Effect of L(---)Sorbose on Cellulase Activity in Trichoderma reesei QM9414
More LessSUMMARY: L(---)Sorbose enhanced the extracellular levels of endoglucanase and filter paper unit activity in culture filtrates of Trichoderma reesei QM9414 cultivated on cellobiose or Avicel cellulose. Addition of sorbose to the culture medium retarded the uptake of cellobiose by the organism; this uptake appeared to be dependent on the surface-bound β-glucosidase. A biochemical mechanism to explain the effect of sorbose on cellulase induction, through its effect on surface-bound β-glucosidase and cellobiose uptake, is proposed.
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Nutritional Variation in Escherichia coli
More LessSUMMARY: Nutritional tests were carried out on 62 strains of Escherichia coli as part of a study on the genetic basis of natural nutritional variation. The ability of these strains to utilize 84 compounds as carbon, nitrogen and carbon plus nitrogen sources was tested using an auxanographic method. The tests revealed polymorphic characters which are suitable for genetic analysis. Very few of these strains grew on the amino acids classified as “essential” for humans.
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- Systematics
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Characterization of Enterobacter cloacae and E. sakazakii by Electrophoretic Polymorphism of Acid Phosphatase, Esterases, and Glutamate, Lactate and Malate Dehydrogenases
Ph. Goullet and B. PicardSUMMARY: Acid phosphatase, esterases, and glutamate, lactate and malate dehydrogenases of 34 strains of Enterobacter cloacae and 22 strains of Enterobacter sakazakii were analysed by horizontal polyacrylamide agarose gel electrophoresis and by isoelectrofocusing in thin-layer polyacryl-amide gel. The two species could be separated on the basis of distinct electrophoretic patterns of all enzymes analysed. Glutamate dehydrogenase and acid phosphatase were detected exclusively in E. cloacae, whereas esterase bands were more intensively stained in E. sakazakii. For each species, two zymotypes could be distinguished, on the basis of electrophoretic mobilities of malate dehydrogenase and banding patterns of esterase for E. cloacae, and by both isoelectric point and electrophoretic mobilities of an esterase and of lactate and malate dehydrogenases for E. sakazakii. The high degree of enzyme polymorphism within the two species permitted precise identification of strains. The variations in electrophoretic patterns might therefore provide useful epidemiological markers.
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A Numerical Taxonomic Study of Anaerobic Gram-negative Bacilli Classified as Bacteroides ureolyticus Isolated from Patients with Non-gonococcal Urethritis
More LessSUMMARY: A numerical taxonomic study of 64 strains of anaerobic Gram-negative bacilli isolated from men with non-gonococcal urethritis, two unclassified laboratory strains of "corroding bacilli”, and 12 other strains of anaerobic Gram-negative bacilli, including nine received as anaerobic curved rods and three as "Bacteroides corrodens” (B. ureolyticus), isolated from women with bacterial vaginosis, was undertaken. Seventeen reference anaerobic strains belonging to the genera Bacteroides, Fusobacterium, Mobiluncus, Mitsuokella and Wolinella were included. Morphological, biochemical and physiological characteristics were examined in 103 tests. The resemblance between the 95 strains was calculated using the SSM, SJ and DP coefficients for cluster analyses based on the UPGMA method. All three approaches gave similar groupings, and the estimated average probability of test error was 2.46%. The strains fell into 10 phenons. The unclassified strains from men and three from women with lower genital-tract infections, and the laboratory strains of "corroding bacilli” clustered in one phenon with the reference strains of B. ureolyticus, indicating that they correspond to B. ureolyticus. The other unclassified strains of anaerobic curved rods clustered as a distinct phenon. They correspond to species of the newly described genus Mobiluncus. The taxonomic data and the compilation of diagnostic tables serve as a useful guide for the laboratory identification of clinical isolates regarded as B. ureolyticus.
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- Short Communication
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The Cellular Location of Proteases in Candida albicans
More LessSUMMARY: Vacuoles prepared from yeast cells of Candida albicans were enriched in proteinase ycaB (EC 3.4.21.48) but not in aminopeptidase or β-glucosidase. Proteinase ycaB, assayed in situ, increased 1.5-fold during starvation whereas aminopeptidase activity decreased by 25%. Proteinase ycaB increased a further 1.5-fold during germ-tube formation.
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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)