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Showing papers in "Fems Microbiology Letters in 1989"


Journal ArticleDOI
TL;DR: It was shown that this gene was poorly expressed in the wild type situation whereas after cloning in acrystalliferous strains of B. thuringiensis large amounts of crystal protein were obtained.
Abstract: A shuttle vector containing the replication region of a resident plasmid of B. thuringiensis, was used to determine the conditions allowing efficient transformation of B. thuringiensis by electroporation. Using this plasmid a δ-endotoxin gene was cloned and expressed both in Escherichia coli and B. thuringiensis. It was shown that this gene was poorly expressed in the wild type situation whereas after cloning in acrystalliferous strains of B. thuringiensis large amounts of crystal protein were obtained.

388 citations


Journal ArticleDOI
TL;DR: In carbon-limited cultures, PHB-synthase was predominantly soluble, becoming granule-associated on transition to nitrogen limitation, and PHB does not measurably turn over under steady-state polymer-accumulating conditions.
Abstract: Alcaligenes eutrophus can accumulate poly-3-hydroxybutyrate (PHB) or polyhydroxyalkanoate (PHA) containing only 3-hydroxybutyrate (HB) and 3-hydroxyvalerate (HV) units. Granule-associated PHB-synthase was active with D (−)-3-hydroxybutyryl-CoA and D (−)-3-hydroxyvaleryl-CoA of the range of D (−)- and L (+)-3-hydroxyacyl-CoA substrates tested (C 4 –C 10 ). In carbon-limited cultures, PHB-synthase was predominantly soluble, becoming granule-associated on transition to nitrogen limitation. Granule-associated PHB-synthase increased in activity at least up to pH 10.0 and K m values of 0.68 mM and 1.63 mM were determined for the C 4 and C 5 substrates, respectively, at pH 8.5. The soluble PHB-synthase, which was unstable, showed equal activity in the range pH 8.0–10.0, had a K m value for D (−)-3-hydroxybutyryl-CoA of 0.72 mM and an M r of 160,000. PHB does not measurably turn over under steady-state polymer-accumulating conditions.

246 citations


Journal ArticleDOI
TL;DR: Using the polymerase chain reaction and synthetic primers, the feasibility of this gene amplification technique for rapid sequence determination of the major 16S ribosomal RNA domains from small amounts of input DNA is demonstrated.
Abstract: Ribosomal RNA sequences are an appealing target for bacterial classification as well as for development of group- or species-specific DNA probes. Using the polymerase chain reaction and synthetic primers, the feasibility of this gene amplification technique for rapid sequence determination of the major 16S ribosomal RNA domains from small amounts of input DNA is demonstrated. Information useful for phylogenetic classification as well as for construction of specific DNA probes may be obtained by comparison with known sequences.

213 citations


Journal ArticleDOI
TL;DR: Cultures with H2 as energy source resulted in the enrichment of chemolithotrophic homoacetogenic bacteria whenever incubation temperatures were lower than 20°C, and Hydrogenotrophic methanogens could only be enriched at 30°C from anoxic paddy soil.
Abstract: The effect of temperature on CH4 production, turnover of dissolved H2, and enrichment of H2-utilizing anaerobic bacteria was studied in anoxic paddy soil and sediment of Lake Constance. When anoxic paddy soil was incubated under an atmosphere of H2/CO2, rates of CH4 production increased 25°C, but decreased at temperatures lower than 20°C. Chloroform completely inhibited methano-genesis in anoxic paddy soil and lake sediment, but did not or only partially inhibit the turnover of dissolved H2, especially at low incubation temperatures. Cultures with H2 as energy source resulted in the enrichment of chemolithotrophic homoacetogenic bacteria whenever incubation temperatures were lower than 20°C. Hydrogenotrophic methanogens could only be enriched at 30°C from anoxic paddy soil. A homoacetogen

209 citations



Journal ArticleDOI
W.A. Corpe1, S. Rheem1
TL;DR: Pink-pigmented, facultatively methylotrophic bacteria (PPFMs) are a substantial part of the aerobic, heterotrophic, microflora of young leaf surfaces, and were most numerous on white clover leaves in the summer.
Abstract: Pink-pigmented, facultatively methylotrophic bacteria (PPFMs) are a substantial part of the aerobic, heterotrophic, microflora of young leaf surfaces. They were most numerous on white clover ( Trifolium repens ) leaves in the summer. The pink bacteria averaged 36% of the total heterotrophic count/cm 2 , with a range of 3 to 79%. The growth of PPFMs on multicarbon compounds is much lower than that of other numerically important leaf heterotrophs. Free methanol of endogenous origin, is present in growing leaves. The availability of methanol at the leaf surface may allow the PPFMs to compete successfully with other heterotrophs that require multicarbon compounds, that are also leached from the growing plant surfaces. SEM studies showed epiphytic bacteria to be most abundant near the margins of the abaxial surfaces of leaves. Microcolonies of bacteria on leaf surfaces were often covered with a thin layer of material, the source and nature of which has not been determined.

194 citations


Journal ArticleDOI
TL;DR: High-frequency electroporation of whole Corynebacterium glutamicum cells without enzymatic pretreatment was achieved under optimized conditions concerning growth stage, washing of cells, cell concentration and pulse parameter transformation efficiencies of far more than 10 transformants per microgram pWST4B plasmid DNA were reached.
Abstract: High-frequency electroporation of whole Corynebacterium glutamicum cells without enzymatic pretreatment was achieved. Under optimized conditions concerning growth stage, washing of cells, cell concentration and pulse parameters transformation efficiencies of far more than 107 transformants per μg pWST4B plasmid DNA were reached. Using electroporation, linearised and subsequently religated plasmid as well as chimeric ligase reaction products were directly introduced into C. glutamicum with reasonable efficiencies. Electrotransformation efficiency was reduced about 105-fold for plasmid DNA cycled through E. coli JM83. Restriction deficient mutants of C. glutamicum were isolated which could be efficiently transformed with foreign DNA.

168 citations


Journal ArticleDOI
TL;DR: Two oligomer probes that are broadly homologous to conserved eubacterial 16S ribosomal RNA (rRNA) sequences not present in human 18 rRNA or human mitochondrial 12S rRNA are described and characterize and offer advantages over more narrowly specific probes for detecting organisms whose identity is unknown.
Abstract: In this report we describe and characterize two oligomer probes that are broadly homologous to conserved eubacterial 16S ribosomal RNA (rRNA) sequences not present in human 18 rRNA or human mitochondrial 12S rRNA. One or both of the probes can detect all of 23 phylogenetically diverse eubacterial nucleic acids against which they were tested by dot blot hybridization. A sensitivity of about 1 bacterium per 10 eukaryotic cells was achieved. By using these oligomer sequences or their complements as primers in the polymerase chain reaction (PCR), the equivalent of 1 pg of E. coli DNA was detected in the presence of a large excess of eukaryotic DNA. Information useful for partial phylogenetic classification of detected organisms may be obtained by direct sequence analysis of the amplified DNA and comparison with known sequences or catalogs. Such broadly homologous probes offer advantages over more narrowly specific probes for detecting organisms whose identity is unknown. They could thus be employed for recognizing infection by organisms that cannot be cultured as may occur, for example, in tissue culture or in plant or animal diseases of unknown cause, provided the probes fail to hybridize with host nucleic acids.

160 citations


Journal ArticleDOI
TL;DR: This protocol, based on high-voltage electro-transformation (electroporation) in the presence of polyethylene glycol, allows introduction of plasmid DNA in most of the Bacillus thuringiensis strains tested.
Abstract: A simple and reliable method of transforming Bacillus thuringiensis is described. This protocol, based on high-voltage electro-transformation (electroporation) in the presence of polyethylene glycol, allows introduction of plasmid DNA in most of the Bacillus thuringiensis strains tested. Efficiencies vary between 102 and 105 transformants per μg DNA, depending on the strain or the replicon used.

158 citations


Journal ArticleDOI
TL;DR: Two organisms have been newly isolated which do this in anaerobic coculture, one of which reduces selenite to elemental selenium and the other, a Pseudomonas species, was shown to respire selenate to selenites.
Abstract: The high levels of selenium (selenate, selenite) in agricultural drainage water in the San Joaquin Valley of California, which have led to environmental problems, might be lowered if the selenate/selenite could be reduced to elemental insoluble selenium [1]. Two organisms have been newly isolated which do this in anaerobic coculture. One, a strictly anaerobic, Gram-positive rod, reduces selenite to elemental selenium. The other, a Pseudomonas species, was shown to respire selenate to selenite. Cells grown anaerobically in Minimal Medium on acetate plus selenate oxidized 14C-acetate to 14CO2 with concomitant reduction of selenate to selenite and small amounts of elemental selenium.

147 citations


Journal ArticleDOI
TL;DR: A 0.2-kb DNA sequence specific to Mycobacterium paratuberculosis, the causative organism of Johne's disease, was isolated from a partial genomic library and may be useful for developing a diagnostic test for Johne’s disease.
Abstract: A 0.2-kb DNA sequence specific to Mycobacterium paratuberculosis, the causative organism of Johne's disease, was isolated from a partial genomic library. The sequence was part of a larger repetitive DNA element and was present in strains of M. paratuberculosis from cattle, sheep, goat, deer and also a woman with Crohn's disease but not in M. paratuberculosis strain 18. The sequence was not present in strains of 19 other mycobacterial species including 31 reference serotype strains of the M. avium-M. intracellular-M. scrofulaceum (MAIS) complex, some strains of which are closely related to M. paratuberculosis. The sequence may be useful for developing a diagnostic test for Johne's disease.

Journal ArticleDOI
TL;DR: It is believed that the microbodies found in six anaerobic ciliated protozoa are hydrogenosomes, that they are derived from mitochondria, and that their biochemical modification has incurred little change in the original mitochondrial ultrastructure.
Abstract: Microbodies in six anaerobic ciliated protozoa (Metopus, Brachonella, Plagiopyla, Parablepharisma, Sonderia, Saprodinium) were found to be enclosed by two membranes. The inner membrane showed extensive infolding, division stages were observed, and in all genera apart from Sonderia and Parablepharisma, the microbodies contained an hydrogenase and were attached to methanogenic bacteria. Some of these ciliates are related to aerobic species with mitochondria. We believe that the microbodies are hydrogenosomes, that they are derived from mitochondria, and that their biochemical modification has incurred little change in the original mitochondrial ultrastructure. These observations weaken the case for the independent origin of hydrogenosomes from anaerobic prokaryotes.

Journal ArticleDOI
TL;DR: Extractable cell membrane-derived polarlipid ester-linked fatty acids (PLFA) obtained from aerated soils gassed with methane or propane and from methane- and propane-oxidizing bacteria isolated from the soils were analyzed by capillary gas chromatography/mass spectrometry as discussed by the authors.
Abstract: Extractable cell membrane-derived polarlipid ester-linked fatty acids (PLFA) obtained from aerated soils gassed with methane or propane and from methane- and propane-oxidizing bacteria isolated from the soils were analyzed by capillary gas chromatography/mass spectrometry. Exposure of aerated soils to methane resulted in the formation of a high proportion of an unusual 18-carbon mono-unsaturated PLFA, 18:lw8c. High proportions of this fatty acid biomarker are found in monocultures from this soil grown in minimal media with methane. This PLFA has been previously established as associated with authentic type II methane-oxidizing bacteria. The microbiota in aerated soils exposed to hydrocarbons containing propane, formed a suite of PLFA characterized by high proportions of a 16-carbon mono-unsaturated acid, 16:lw6c, and an 18-carbon saturated fatty acid with an additional methyl branch at the 10 position, 10 Me 18:0. This PLFA pattern has been detected in several monocultures enriched from the soil with propane-amended minimal media. The correspondence of high proportions of these unusual mono-unsaturated PLFA in the isolated monocultures and in situ in the soils after stimulation with the appropriate hydrocarbon is a strong validation of the utility of these biomarkers in defining the community structure of the surface soil microbial community.

Journal ArticleDOI
TL;DR: A simple procedure based on the polymerase chain reaction has been developed to detect Mycobacterium leprae, rapidly and unambiguously, in biological samples, and its application to small numbers of M. lePrae cells is discussed.
Abstract: A simple procedure based on the polymerase chain reaction has been developed to detect Mycobacterium leprae, rapidly and unambiguously, in biological samples. Its application to small numbers of M. leprae cells (approximately 10(2] isolated from armadillo liver, mouse footpads or human biopsies is discussed.

Journal ArticleDOI
TL;DR: In this paper, a simple model of simultaneous NO production and NO uptake was proposed and the dependence of net NO fluxes on gas flow rates and on NO mixing ratios could be described by using this model, rates of gross NO production, rate constants of NO uptake, and NO compensation mixing ratios were determined as function of the soil type and the incubation condition.
Abstract: Fluxes of NO from three different soils have been studied by a flow-through system in the laboratory as a function of gas flow rate, of NO mixing ratio, and of incubation conditions. The dependence of net NO fluxes on gas flow rates and on NO mixing ratios could be described by a simple model of simultaneous NO production and NO uptake. By using this model, rates of gross NO production, rate constants of NO uptake, and NO compensation mixing ratios could be determined as function of the soil type and the incubation condition. Gross NO production rates were one to two orders of magnitude larger under anaerobic than under aerobic conditions. NO uptake rate constants, on the other hand, were only 5–8 times larger so that the compensation mixing ratios of NO were in a range of about 1600–2200 ppbv under anaerobic and of about 50–600 ppbv under aerobic conditions. The different soils exhibited similar NO uptake rate constants, but the gross NO production rate and compensation mixing ratio was significantly higher in an acidic (pH 4.7) sandy clay loam than in other less acidic soils. Experiments with autoclaved soil samples showed that both NO production and NO uptake was mainly due to microbial metabolism.

Journal ArticleDOI
TL;DR: DNA from representative strains of Fusobacterium nucleatum subgroups Fn-1, Fn-2 and Fn-3 was digested with restriction enzymes EcoRI and TaqI and the electrophoretically separated fragments hybridized with a 32P-16S rRNA gene probe from E. coli to identify the three subgroups.
Abstract: DNA from representative strains of Fusobacterium nucleatum subgroups Fn-1, Fn-2 and Fn-3 was digested with restriction enzymes Eco RI and Taq I and the electrophoretically separated fragmetns hybridized with a 32 P-16S rRNA gene probe from E. coli . The rRNA gene restriction patterns from DNA digested with either enzyme allowed the clustering of strains into the three subgroups. However, Taq I digested DNA yielded a wider distribution of taxonomically useful bands (ca 0.65 ± 14.3 kbp) and the pattern produced was characteristic of each subgroup. The present method is a simple and reliable means of identifying the three subgroups of F. nucleatum and provides a useful method for further studies of the heterogeneity of F. nucleatum .

Journal ArticleDOI
TL;DR: The depth horizon at which maximum populations of purple sulfur bacteria were recorded often did not coincide with the sulfide/oxygen interface but was located closer to the sediment surface where polysulfides, polythionates, elemental sulfur and occasionally thiosulfate were present.
Abstract: Laminated microbial sediment ecosystems which develop in the upper tidal zone of Scapa Flow beaches, Orkney Islands were investigated with respect to depth profiles of chlorophyll a , bacteriochlorophyll a , pH, redox, oxygen and the following inorganic sulfur compounds: free sulfide, FeS, polysulfides, polythionates, elemental sulfur and thiosulfate. In addition, particle size distribution and light penetration were determined at all sampling locations. Three main types of laminated sediment ecosystems were recognized, designated the ‘classical’ type (layer of cyanobacteria underlain by layer of purple sulfur bacteria), the ‘single-layer’ type (chlorophyll a containing organisms absent, purple sulfur bacteria at sediment surface), and the ‘inverted’ type (chlorophyll a containing organisms underlying purple sulfur bacteria). The dominant purple sulfur bacterium was Thiocapsa roseopersicina and Chromatium vinosum was observed less commonly. The principal cyanobacterium found in these sulfureta was Oscillatoria sp. The depth horizon at which maximum populations of purple sulfur bacteria were recorded often did not coincide with the sulfide/oxygen interface but was located closer to the sediment surface where polysulfides, polythionates, elemental sulfur and occasionally thiosulfate were present. The structure of these sulfureta is discussed in relation to the chemolithotrophic growth capacities of Thiocapsa in the presence of oxygen.

Journal ArticleDOI
TL;DR: The two restriction enzymes SmaI and ApaI were found to produce distributions of DNA fragments useful for genome analysis of some lactic acid bacteria by pulsed-field gel electrophoresis.
Abstract: The two restriction enzymes SmaI and ApaI were found to produce distributions of DNA fragments useful for genome analysis of some lactic acid bacteria (Lactococcus lactis and Streptococcus salivarius subsp. thermophilus) by pulsed-field gel electrophoresis. The genome size was estimated to be 1750 to 2500 kb depending on the species. Each strain displayed unique restriction patterns; nevertheless, the percentage of the comigrating fragments of two isogenic or closely related strains was about 80% and fell to 20–40% when the patterns of two non-related strains of the same species or two strains belonging to different species were compared.

Journal ArticleDOI
TL;DR: In this paper, the authors found that the contribution of MBA to H2-dependent methanogenesis and turnover of dissolved H2 did not change significantly for up to 7 months of incubation.
Abstract: Interspecies H2 transfer within methanogenic bacterial associations (MBA) accounted for 95–97% of the conversion of 14CO2 to 14CH4 in anoxic paddy soil. Only 3–5% of the 14CH4 were produced from the turnover of dissolved H2. The H2-syntrophic MBA developed within 5 days after the paddy soil had been submerged and placed under anoxic atmosphere. Afterwards, both the contribution of MBA to H2-dependent methanogenesis and the turnover of dissolved H2 did not change significantly for up to 7 months of incubation. However, while the rates of H2-dependent methanogenesis stayed relatively constant, the rates of total methanogenesis decreased. The contribution of MBA to H2-dependent methanogenesis was further enhanced to 99% when the temperature was shifted from 30°C to 17°C, or when the soil had been planted with rice. This enhancement was partially due to an increased utilization of dissolved H2 by chloroform-insensitive non-methanogenic bacteria, most probably homoacetogens, so that CH4 production was almost completely restricted to H2-syntrophic MBA. The activity of MBA, as measured by the conversion of 14CO2 to 14CH4, was stimulated by glucose, lactate, and ethanol to a similar or greater extent than by exogenous H2. Propionate and acetate had no effect.

Journal ArticleDOI
TL;DR: In this article, the anaerobic, thermophilic archaebacterium, Pyrobaculum islandicum (Geo 3) was examined for the presence of lipoquinones.
Abstract: The anaerobic, thermophilic archaebacterium, Pyrobaculum islandicum (Geo 3) was examined for the presence of lipoquinones. Thin layer chromatographic, HPLC, UV, and mass spectroscopic analysis showed that a menaquinone was present. No evidence was found for substitution of the 2-methyl-3-polyisoprenyl-1,4-naphthoquinone ring nucleus. However, the C3 isoprenoid chain consisted of six fully saturated units, and shows that the major menaquinone in this organism corresponds to 2-methyl-3-VI,V,IV,III,II,I-dodecahydrohexaprenyl-1, 4-naphthoquinone (MK-6H12).

Journal ArticleDOI
TL;DR: The isolation of a new lantibiotic, gallidermin, has been isolated from Staphyloccus gallinarum and its structural gene is named gdmA, which codes for a 52 amino acid residue prepeptide, consisting of an alpha-helical leader sequence of hydrophilic character.
Abstract: Peptide antibiotics containing lanthionine and 3-methyllanthionine bridges, named lantibiotics [1], are of increasing interest. A new lantibiotic, gallidermin, has been isolated from Staphylococcus gallinarum. Here we report the isolation of its structural gene which we name gdmA. In all lantibiotics so far studied genetically, three peptides can be formally distinguished: (i) the primary translation product, which we call the prepeptide; (ii) the propeptide lacking the leader sequence and (iii) the mature lantibiotic. Unlike the plasmid-coded epidermin, gdmA is located on the chromosome. The gdmA locus codes for a 52 amino acid residue prepeptide, consisting of an α-helical leader sequence of hydrophilic character, which is separated from the C-terminus (propeptide) by a characteristic proteolytic processing site (Pro−2 Arg−1 Ile1). Although pro-gallidermin

Journal ArticleDOI
TL;DR: By helper-assisted and unassisted conjugation the plasmids of strain 31A were shown to carry nickel and cobalt resistance determinants, which carried resistance properties which were expressed in all recipients except A. eutrophus H16, in which only nickel resistance was expressed.
Abstract: From enrichment cultures in the presence of 1 mM NiCl2 200 strains of aerobic bacteria were isolated from 50 samples collected in the metal-processing industry, waste water treatment plants and from solid waste, highly polluted by heavy metals. The strains isolated were characterized with respect to their substrate spectrum and resistance to nickel, cobalt, zinc and cadmium salts and assigned to 21 groups. One representative of each group was described with respect to cell morphology. All strains were Gram-negative, non-sporing rods or cocci. The highest concentrations of nickel, cobalt, zinc, cadmium, copper, mercury, and silver allowing growth on solid media were estimated. Two strains were able to grow at 20 mM NiCl2 and CoCl2, one strain tolerated 12 mM and one 7.5 mM concentrations of these salts. Fifteen out of 21 strains contained at least one plasmid two contained two plasmids. The plasmid sizes varied between 50 and 340 kbp, except strain 10A, which contained a miniplasmid (2.6 kbp). Attempts to cure four selected strains by exposure to mitomycin C or growth at elevated temperature failed. By helper-assisted and unassisted conjugation the plasmids of strain 31A were shown to carry nickel and cobalt resistance determinants. Alcaligenes eutrophus strains H16 and N9A and denative of strain CH34 lacking one or both of its native metal resistance plasmids were used as recipients. Both plasmids, p TOM8 and pTOM9, of strain 31A carried resistance properties which were expressed in all recipients except. A. eutrophus H16, in which only nickel resistance was expressed. Plasmid pTOM3 residing in strain 10A could not be transferred as such. However, transconjugants derived from helper (pULB113)-assisted matings carried co-integrates of various sizes and were resistant to nickel and cobalt.

Journal ArticleDOI
TL;DR: Genetic evidence combined with this and previous sequencing data indicate that the genes entCEB(G)A are transcribed as unit from a promoter upstream of entC.
Abstract: The Escherichia coli entE gene encodes a polypeptide necessary in the latter stages of biosynthesis of the siderophore enterobactin. The entE gene and adjacent DNA were sequenced. The predicted EntE polypeptide consists of 536 amino acids and has a Mr of 58 299 and a net charge of −7.33. Genetic evidence combined with this and previous sequencing data indicate that the genes entCEB(G)A are transcribed as unit from a promoter upstream of entC.

Journal ArticleDOI
TL;DR: An irregular fiord-like outline of a S. marcescens colony expanding on a hard agar medium was shown to be fractal which promised an extremely long array of outermost cells.
Abstract: An irregular fiord-like outline of a S. marcescens colony expanding on a hard agar medium was shown to be fractal which promised an extremely long array of outermost cells. For the analysis of such spreading growth, mutants defective in production of surface active exolipids (serrawettin W1 and W3) and flagella-less mutants were isolated. The fractal spreading growth was found to be correlated with serrawettin production. Furthermore, serrawettin-less mutants demonstrated spreading growth when purified serrawettin W1 or W3 were supplied exogenously.

Journal ArticleDOI
TL;DR: Two dibenzofuran degrading bacteria were found to utilize fluorene as sole source of carbon and energy and the presence of a novel type of dioxygenase, attacking polynuclear aromatic systems in the unusual angular position was indicated.
Abstract: Two dibenzofuran degrading bacteria, Brevibacterium strain DPO 1361 and strain DPO 220, were found to utilize fluorene as sole source of carbon and energy. Cells which were grown on dibenzofuran, transformed fluorene into a number of products. For five of the seven metabolites isolated, the structure could be established unequivocally. Accumulation of one metabolite, 1,10-dihydroxy-1, 10-dihydrofluoren-9-one, indicated the presence of a novel type of dioxygenase, attacking polynuclear aromatic systems in the unusual angular position. Dibenzofuran degradation is proposed to likewise proceed via initial angular dioxygenation. Only aryl oxygen ether bond, which normally is extremely stable, is thus transformed to a hemiacetal. After spontaneous cleavage and subsequent rearomatization by dehydration, 2,2′,3-trihydroxybiphenyl [3-(2-hydroxyphenyl)-catechol] thus results as the immediate product of the first enzymatic reaction in the degradation sequence.

Journal ArticleDOI
TL;DR: Part of the gene coding for the immunodominant 47 kDa antigen of the human fungal pathogen Candida albicans was cloned and sequenced and was homologous to stress proteins, the most extensive similarity being with the heat shock protein hsp 90 of Saccharomyces cerevisiae.
Abstract: Part of the gene coding for the immunodominant 47 kDa antigen of the human fungal pathogen Candida albicans was cloned and sequenced. The predicted amino acid sequence was homologous to stress proteins, the most extensive similarity being with the heat shock protein hsp 90 of Saccharomyces cerevisiae. The 47 kDa antigen has diagnostic and therapeutic potential and is the first candidal antigen to be cloned and sequenced.

Journal ArticleDOI
TL;DR: From epidemiological data of human infections in England and Wales, it is suggested that strains of S. enteritidis PT7 may be less virulent for humans, and the loss of ability of strains of PT4 to snythesise LPS is responsible for the conversion of highly virulent strains ofPT4 to avirulent strain of PT7.
Abstract: Three strains of Salmonella enteritidis phage type 4 (PT4) and 33 strains of S. enteritidis phage type 7 (PT7) were examined for the ability to produce lipopolysaccharide (LPS) and for plasmid carriage. The LPS of all strains of PT4 gave a typical ‘ladder’ pattern by SDS-PAGE and silver staining, and on serotyping these strains were shown to express the O-antigens 9, 12. In contrast, strains of PT7 did not express long-chain LPS and were autoagglutinable. All strains of PT4 and the majority of strains of PT7 carried a single plasmid of 38 MDa, indistinguishable when characterised by restriction endonuclease fragmentation analysis. Epidemiological and experimental observations have demonstrated a relationship between strains of S. enteritidis PT4 and PT7, and our results, using mice, show that the loss of ability of strains of PT4 to sythesise LPS is responsible for the conversion of highly virulent strains of PT4 to avirulent strains of PT7. From epidemiological data of human infections in England and Wales, we suggest that strains of S. enteritidis PT7 may be less virulent for humans.

Journal ArticleDOI
TL;DR: The results indicate that 6 human strains, a single clinical isolate and a strain from bovine mastitis are genetically distinct from each other and all other previously described Enterococcus species and constitute three new species.
Abstract: Deoxyribonucleic acid base composition, deoxyribonucleic acid-deoxyribonucleic acid hybridization, and biochemical studies were performed on some enterococci from clinical sources of uncertain taxonomic position. Our results indicate that 6 human strains, a single clinical isolate and a strain from bovine mastitis are genetically distinct from each other and all other previously described Enterococcus species and constitute three new species, for which the names Enterococcus raffinosus, Enterococcus solitarius and Enterococcus pseudoavium are proposed.

Journal ArticleDOI
TL;DR: After inhibition of ring cleavage activities with 3-chlorocatechol, 2-chlorobenzoate was transformed to catechol in nearly stoichiometric amounts and other ortho-substituted benzoates like anthranilate and 2-methoxybenzoate seem to be metabolized via the same route.
Abstract: Pseudomonas putida strain CLB 250 (DSM 5232) utilized 2-bromo-, 2-chloro- and 2-fluorobenzoate as sole source of carbon and energy. Degradation is suggested to be initiated by a dioxygenase liberating halide in the first catabolic step. After decarboxylation and rearomatization catechol is produced as a central metabolite which is degraded via the ortho-pathway. After inhibition of ring cleavage activities with 3-chlorocatechol, 2-chlorobenzoate was transformed to catechol in nearly stoichiometric amounts. Other ortho-substituted benzoates like anthranilate and 2-methoxybenzoate seem to be metabolized via the same route.

Journal ArticleDOI
TL;DR: Nine strains of Salmonella enteritidis phage type 4 were examined for virulence in BALB/c mice and it is suggested that the enhanced virulence of the current strains for poultry is unlikely to be the result of changes in the 38 MDa plasmid.
Abstract: Nine strains of Salmonella enteritidis phage type 4 were examined for virulence in BALB/c mice. The possession of a 38 MDa plasmid was necessary for full virulence. Strains carrying this plasmid had LD50 values of less than 20 bacteria whilst plasmid-free strains had LD50 values of greater than 10(6) bacteria when challenged intraperitoneally. Pathogenesis of disease involved the widespread distribution of bacteria throughout the tissues. Possession of the 38 MDa plasmid could not be linked with the ability of strains to express novel outer membrane proteins, to produce toxins affecting Vero, Y1, HeLa, Henle or HEp-2 cells, or to invade HEp-2 cells. Furthermore, the 38 MDa plasmid did not encode an aerobactin-mediated iron uptake system or the production of a haemolysin. Strains of S. enteritidis PT4 isolated in 1967, 1978 or 1979 and possessing the 38 MDa plasmid showed the same virulence properties as the current plasmid-carrying strains. This suggests that the enhanced virulence of the current strains for poultry is unlikely to be the result of changes in the 38 MDa plasmid.