Showing papers in "Current Microbiology in 1987"
TL;DR: Methane enrichment of twenty-three 100-ml portions of seawater from three stations in the Sargasso Sea yielded the same obligate type I methanotroph, which is pigmented white, requires NaCl, grows well in seawater with either methane or methanol, but not on other C1 compounds nor on C−C bonded organic matter.
Abstract: Methane enrichment of twenty-three 100-ml portions of seawater from three stations in the Sargasso Sea yielded the same obligate type I methanotroph. It is pigmented white, requires NaCl, grows well in seawater with either methane or methanol, but not on other C1 compounds nor on C−C bonded organic matter, and it uses either ammonia or nitrate but not dinitrogen as a nitrogen source. Formaldehyde is produced in marked amounts from methanol. Growth occurs at 20° and 30°C but not at 10°C and is inhibited in natural sunlight. Representative isolates from each hydrographic station assimilate one-carbon units via the ribulose monophosphate pathway for formaldehyde fixation, and have a DNA base composition of 49 mol% guanine plus cytosine. The type strain, NCMB 2265, has been namedMethylomonas pelagica sp. nov. This upper ocean methanotroph may obtain its C1 substrates in situ from particles of algal debris that become anoxic, ferment, and accumulate in the thermocline to form a false benthos.
114 citations
TL;DR: Nondialyzable bioemulsifiers were found in the extracellular fluid of 16 different strains of Acinetobacter calcoaceticus following growth on ethanol-salts medium, and with one exception, hexadecane/2-methylnaphthalane mixtures were emulsified more efficiently than pure hexADEcane or 2-ethylnaphalane.
Abstract: Methods and compositions are provided for the preparation and use of new nondialyzable, interfacially-active bioemulsifiers from Acinetobacter calcoaceticus strains.
98 citations
TL;DR: Both species grew prolifically on protein hydrolysates containing peptides, but grew poorly on acid-hydrolyzed casein even when supplemented with amino acids.
Abstract: Growth ofBacteroides intermedius was promoted only moderately by glucose, and the incorporation of14C-glucose into cells was limited. WithBacteroides gingivalis growth promotion was negligible and glucose incorporation even more restricted. Both species grew prolifically on protein hydrolysates containing peptides, but grew poorly on acid-hydrolyzed casein even when supplemented with amino acids. These results are discussed in relation to the ecological distribution of these species compared to saccharolytic bacteroides.
79 citations
TL;DR: Serial enrichment was used to obtain a strain of Clostridium acetobutylicum demonstrating a 40% increase in tolerance to added butanol and a further 17% improvement in the ability to produce butanol, with a disappointly low titer of butanol produced by the new strain.
Abstract: Serial enrichment was used to obtain a strain ofClostridium acetobutylicum demonstrating a 40% increase in tolerance to added butanol and a further 17% improvement in the ability to produce butanol. The glucose and the butyrate consumption were higher for the G1 variant than for the wild-type strain. In consideration of the higher butanol tolerance, a disappointly low titer of butanol was produced by the new strain. This can be explained by the higher level of autobacteriocin produced by G1. Control of autobacteriocin production appears to be one of the key factors limiting the potential of the acetone butanol fermentation.
75 citations
TL;DR: The adherence ofCandida yeasts to monolayers of human intestinal epithelium was studied in order to determine the specific and nonspecific mechanisms that might contribute to yeast adherence.
Abstract: The adherence ofCandida yeasts to monolayers of human intestinal epithelium was studied in order to determine the specific and nonspecific mechanisms that might contribute to yeast adherence. Multiple factors were shown to significantly affect the adherence of yeasts to intestinal cells. It was demonstrated that hydrophobic yeasts adhered two times greater than normal yeasts, and positively charged yeasts adhered ten times greater than normal yeasts to monolayers of intestinal epithelium. The binding of yeasts to the intestinal cells was saturable and was most effectively blocked by mucin, which caused an 83% reduction in adherence, whereas the addition ofd-glucose caused a 41% reduction in adherence. Aggregation or coadherence of yeasts occurred as the yeast inocula were increased.Candida appears to possess the ability to adhere to living tissue by several mechanisms, such as adhesin-receptor interactions, nonspecific hydrophobic and ionic bonding, and aggregation or coadherence. This is the first demonstration of multiple forces that may act simultaneously in the process of adherence of yeasts to living cells.
68 citations
TL;DR: These studies indicated that bothK.
Abstract: For a period of 7 months water samples were analyzed for the presence ofKlebsiella pneumoniae and fecal coliforms at 11 sites in a cloud rain forest watershed in Puerto Rico. Diffusion chamber studies were conducted at two sites which were found to contain low numbers of naturally occurringK. pneumoniae and fecal coliforms. These studies indicated that bothK. pneumoniae andEscherichia coli may be capable of surviving environmental conditions for extended periods of time. The presence of both bacteria in pristine natural waters is indicative of their being autochtonous to tropical environments. Thus, as a result, the use of coliform and even fecal coliform bacteria as indicators of fecal pollution may be misleading when applied to countries with a tropical climate.
67 citations
TL;DR: Electron micrographs of thin sections of hindgut protozoa suggest methanogens are endosymbionts in the small trichomonad protozOA, consistent with the finding of Odelson and Breznak that methane is a minor endproduct of the metabolism of termite gut microbiota.
Abstract: Epifluorescence microscopy was used to examine hindgut contents ofZootermopsis angusticollis (Hagen) termites for the presence of methanogenic bacteria, which can be identified on the basis of the fluorescence of the novel cofactors F420 and F350. Small, autofluorescent, rod-shaped bacteria of theMethanobrevibacter sp. morphotype were observed associated with three flagellates tentatively identified asTrichomitopsis termopsidis (Cleveland),Tricercomitus termopsidis Kirby andHexamastix termopsidis Kirby. Methanogens were not observed associated with any other protozoal morphotypes and were not numerous in the free-living state inZ. angusticollis hindgut fluid. Electron micrographs of thin sections of hindgut protozoa suggest methanogens are endosymbionts in the small trichomonad protozoa. Our observations are consistent with the finding of Odelson and Breznak that methane is a minor endproduct of the metabolism of termite gut microbiota.
67 citations
TL;DR: This investigation underlined the discrepancies concerning the action of drugs on extra- and intracellularly multiplying mycobacteria and the advantage of using a continuous cell line model while studying drug susceptibility of myc Cobacterium bovis and M. avium in relation to their intrACEllular growth.
Abstract: The comparative action of seven drugs, namely, rifampicin (RIF), ansamycin-LM 427 (ANS), streptomycin (SM), isoniazid (INH), pyrizinamide (PZA), clofazimine (CLF), and pristinamycin (PST), was studied both on extracellularly and intracellularly growing mycobacterial speciesMycobacterium bovis, M. tuberculosis, andM. avium. All the drugs were used at their minimal inhibitory concentrations (MICs) and their obtainable serum levels in man; 10×MICs, when less than the obtainable serum levels, were also tested. The action of drugs on extracellularly growing bacilli was tested with the Middlebrook 7H9-Tween medium, whereas for intracellular growth, an experimental model using a continuous murine macrophage cell line J-774 was developed, and macrophage-mycobacteria interactions by use of cytochemistry, scanning and transmission electron microscopy were investigated. Extracellularly growingM. avium was resistant to all the drugs tested; however, when tested on intracellularly growing bacilli, both RIF and CLF were found to be bactericidal, whereas other drugs only delayed the bacterial growth. In the case of extracellularly growingM. bovis andM. tuberculosis, INH, RIF, and SM were active, whereas PZA was active only onM. tuberculosis. However, on intracellularly growing bacilli, only INH and RIF were found to be bactericidal for both species, CLF to a lesser extent in the case ofM. tuberculosis; ANS and SM were bacteriostatic, whereas both PZA and PST were without any antibacterial effect. This investigation underlined the discrepancies concerning the action of drugs on extra- and intracellularly multiplying mycobacteria and the advantage of using a continuous cell line model while studying drug susceptibility of mycobacteria in relation to their intracellular growth.
64 citations
TL;DR: A portion of the toxin A gene ofClostridium difficile was cloned into pBR322 with Escherichia coli Chi 1776 as the host, and the cloned DNA appears to code for a nontoxic binding portion of toxin A, which is responsible for binding to galactose-α1-3-galactOSE-β1-4-N-acetylglucosamine.
Abstract: A portion of the toxin A gene ofClostridium difficile was cloned into pBR322 withEscherichia coli Chi 1776 as the host. Five identical clones, each containing a 4.7-kbPstI restriction endonuclease fragment and producing toxin A antigens, were detected with affinity-purified, monospecific antibodies against toxin A. Digestion of the cloned DNA withPstI revealed as internal restriction site that resulted in two fragments (2.1 and 2.6 kb in size). Probe DNA from either of these fragments hybridized with DNA in the 4.7 kb region ofPstI-digested, high-molecular-weight DNA from the sourceC. difficile strain, indicating that the internalPstI site is protected. The probe DNA also hybridized with restriction-digested DNA from five additional toxigenic strains, but it did not hybridize with DNA from four nontoxigenic strains. In addition, a DNA fragment from a toxigenic strain ofClostridium sordellii, whose toxin cross-reacts with antibody toC. difficile toxin A, hybridized with the clonedC. difficile DNA. Unlike native toxin A, the cell lysate from the recombinant clone was not cytotoxic to Chinese hamster ovary cells or enterotoxic in hamsters. It did agglutinate rabbit red blood cells, a characteristic of toxin A. The cell lysate also exhibited a line of partial identity when compared with purified toxin A in Ouchterlony assays, and it reacted with monoclonal antibody to toxin A in an enzyme-linked immunosorbent assay. The cloned DNA appears to code for a nontoxic binding portion of toxin A, which is responsible for binding to galactose-α1-3-galactose-β1-4-N-acetylglucosamine.
60 citations
TL;DR: The objective of this study was to evaluate the influence of seawater salts, and more specially sodium chloride, on the recovery of Escherichia coli cells after exposure to natural seawater in laboratory microcosms, and the possible adaptation in this bacterium to high salinity.
Abstract: The objective of this study was to evaluate the influence of seawater salts, and more specially sodium chloride, on the recovery ofEscherichia coli cells after exposure to natural seawater in laboratory microcosms, and the possible adaptation in this bacterium to high salinity. The recovery efficiency of a complex organic medium supplemented with sodium chloride largely depended on the strain and varied with starvation time and salinity. Moreover, cells previously grown on salted medium appeared more able to survive after exposure to seawater. It is assumed that, withinE. coli populations, some cells are able to adapt to seawater in the presence of both salts and organic matter.
59 citations
TL;DR: Bacillus subtilis utilized ferulic acid and its intermediates vanillin, vanillic acid, and protocatechuic acid as sole carbon source and Concentration of the inducer profoundly influenced the induction of the enzymes involved in ferulic Acid dissimilation.
Abstract: Bacillus subtilis utilized ferulic acid and its intermediates vanillin, vanillic acid, and protocatechuic acid as sole carbon source. The enzymes of the ferulic acid degradative pathway such as deacetylase, vanillin oxidase, vanillate-o-demethylase, and protocatechuate 3,4-dioxygenase were inducible in nature. Concentration of the inducer profoundly influenced the induction of the enzymes involved in ferulic acid dissimilation.
TL;DR: The photodynamic effects of deuteroporphyrin (DT) on the growth and viability of Staphylococcus aureus, Streptococcus faecalis, and Bacillus cereus are described and it is shown that the pH dependence of the photodynamic inhibitory effect shows that it is best obtained at pH 6.5.
Abstract: The photodynamic effects of deuteroporphyrin (DT) on the growth and viability ofStaphylococcus aureus, Streptococcus faecalis, andBacillus cereus are described. By exposure to light and DT, the growth ofSta. aureus andStr. Faecalis strains was markedly inhibited, whereasB. cereus was undergoing lysis. Counting the viable bacteria during the DT treatment revealed that more than 99% of the initial bacterial population was killed within the first 30 min of treatment. The pH dependence of the photodynamic inhibitory effect shows that it is best obtained at pH 6.5. No temperature dependence in the range of 37°–44°C could be detected. The best photodynamic effect was achieved when the culture was in the mid-log phase. DT-treated bacteria, when grown in the dark or in the presence of horse serum albumin, were unaffected by the porphyrin action. Electron microscopic examinations ofSta. aureus andStr. faecalis showed the appearance of well-developed mesosomes within the cell cytoplasm.B. cereus preparations have not shown any mesosome formation but showed some lysed cells as well as some spores. None of the mentioned effects by DT and light could be observed on Gramnegative bacteria such asEscherchia coli orPseudomonas aeruginosa.
TL;DR: Two of the proteins, with molecular weights of approximately 55,000 and 32,000, respectively, gave strong and specifically complementary cross-reactions with antibodies raised against subunits I and II of the aa3-type cytochrome oxidase fromParacoccus denitrificans.
Abstract: Cell-free extracts ofAnacystis nidulans were fractionated by discontinuous sucrose density gradient centrifugation resulting in the separation of two distinct types of membranes, the heavier one containing the chlorophyll and the lighter one devoid of chlorophyll. Identity of the latter with plasma membrane was confirmed by labeling of intact cells with impermeant marker,35S-diazobenzenesulfonate, prior to cell disruption. Both membrane fractions were purified individually by repeated recentrifugation on identical gradients. Purified membranes were subjected to dissociating polyacrylamide gel electrophoresis, either type of membranes yielding a distinct polypeptide pattern. After transfer of the polypeptides to nitrocellulose by Western blotting, two of the proteins, with molecular weights of approximately 55,000 and 32,000, respectively, gave strong and specifically complementary cross-reactions with antibodies raised against subunits I and II of the aa3-type cytochrome oxidase fromParacoccus denitrificans. The findings will be discussed in terms of the presence of aa3-type cytochrome oxidase in both plasma and thylakoid membranes ofAnacystis nidulans.
TL;DR: Aspartate as asparagine catabolism was studied in representative strains of Bacteroides intermedius strain T588 and B. gingivalis strain W83 to postulated to occur via oxaloacetate, malate, and fumarate to succinate.
Abstract: Aspartate as asparagine catabolism was studied in representative strains ofBacteroides intermedius strain T588 andB. gingivalis strain W83. Cell suspensions of both species deamidated asparagine. The enzyme asparaginase was constitutive and was unaffected by the addition of ammonium ions to the culture medium. The enzyme aspartase was not detected, but since malate dehydrogenase was known to occur and succinate was present as a major end product of metabolism, aspartate catabolism was postulated to occur via oxaloacetate, malate, and fumarate to succinate. All enzymes of this pathway were present in cell-free extracts, and some of the major properties of these enzymes were examined. The electron carriers cytochrome b and menaquinone-9 were present inB. gingivalis, whereasB. intermedius possessed cytochrome c and menaquinone-11. The membrane-bound enzyme fumarate reductase utilized NADH as an electron donor, but the reaction was inhibited by short wave ultraviolet radiation and 2-n-heptyl-4-hydroxyquinoline-N-oxide.
TL;DR: The ability of virulent and avirulent strains ofVibrio vulnificus to overcome iron limitations by using iron bound to iron-binding proteins was examined and growth was enhanced by the iron-saturated form of these proteins.
Abstract: The ability of virulent and avirulent strains ofVibrio vulnificus to overcome iron limitations by using iron bound to iron-binding proteins was examined. While no strains were able to obtain iron from lactoferrin or ferritin when these proteins were not fully saturated with iron, growth was enhanced by the iron-saturated form of these proteins. None of the strains was able to scavange iron from 30% saturated transferrin, but there were strain differences in the ability to obtain iron from the saturated form. The virulent strains were able to compete more efficiently with transferrin when it was fully saturated with iron than were the avirulent strains.
TL;DR: A microcosm method was developed to investigate survial and fate of genetically engineered bacteria associated with plant surfaces and a plant-feeding insect, the variegated cutworm, Peridroma saucia, and the total epiphytic population had increased approximately fourfold, while the P. cepacia strains had decreased to 2%–30% of their initial numbers.
Abstract: A microcosm method was developed to investigate survial and fate of genetically engineered bacteria associated with plant surfaces and a plant-feeding insect, the variegated cutworm,Peridroma saucia. Larvae on radish plants in microcosms were sprayed with nonrecombinantPseudomonas cepacia and a recombinant strain ofP. cepacia carrying the transmissible plasmid R388::Tn1721. Leaf, whole insect, foregut, and frass samples were periodically assayed over a 48-h period to enumerate total bacteria andP. cepacia strains. Immediately after spraying,P. cepacia comprised about 20%–30% of the total population on leaves, which was 2×107 cfu/g of leaf. Approximately 4×107 total cfu were recovered from each gram of whole insect, when theP. cepacia strains averaged about 3×105 cfu/g. After 2 days, the total epiphytic population had increased approximately fourfold, while theP. cepacia strains had decreased to 2%–30% of their initial numbers. After 24 and 48 h, eachP. cepacia strain numbered between 104 and 105 cfu/g of insect in foregut samples, whereas none was detectable in frass. Plasmid transfer fromP. cepacia R388::Tn1721 to the nonrecombinant recipientP. cepacia strain was not observed.
TL;DR: Investigations carried out on the effect of addition of culture filtrate concentrate and cell-free extract concentrate indicate that nonvolatile inhibitors produced by cells were also inhibitory for bioconversion.
Abstract: Studies carried out onClostridium saccharoperbutylacetonicum (ATCC 27022) reveal that intracellular and extracellular inhibitors, including metabolic end-products, caused the inhibition of cell growth and solvent production. Butanol at the level of 13.0 g/liter was completely inhibitory to the growth of cells, whereas butyric acid totally inhibited the cell growth at a concentration of 8.7 g/liter. Investigations carried out on the effect of addition of culture filtrate concentrate and cell-free extract concentrate indicate that nonvolatile inhibitors produced by cells were also inhibitory for bioconversion. The butanol production was found to be reduced by 15%–20% on addition of cell-free extract concentrate. Inhibition by concentrates was enhanced in the presence of butanol. Addition of heat-sterilized concentrates resulted in a reduction of inhibition.
TL;DR: While in continuous light, each upsurge of nitrogenase activity coincides with a marked drop in the net oxygen production rate; this drop is due largely to a concomitant increase in the dark respiration rate of the culture.
Abstract: All oxygen levels are detrimental to the nitrogenase activity ofSynechococcus RF-1 cells. In continuous light, cultures maintain a high dissolved oxygen concentration and a continuous but usually low rate of nitrogenase activity.
TL;DR: Recombinant human gamma-interferon was shown to inhibit the growth of Chlamydia trachomatis in HEp-2 cells and could be reversed by the addition of tryptophan, which restored C. trachmatis infectivity at low concentrations.
Abstract: Recombinant human gamma-interferon was shown to inhibit the growth ofChlamydia trachomatis (L2/434/Bu) in HEp-2 cells. This inhibition could be reversed by the addition of tryptophan. The effect of tryptophan was dose dependent and determined by the interferon concentration. At low concentrations of interferon, the addition of tryptophan completely restoredC. trachomatis infectivity, whereas at high concentrations (100–1000 IU/ml) the effect of interferon could not be totally reversed. The reversal effect of tryptophan could be achieved even when the addition was 48 h after infection. The probability that tryptophan degradation induced by gamma-interferon might be the mechanism involved in its antichlamydial activity is discussed.
TL;DR: Plumbagin (5-hydroxy-2-methyl-1,4-naphthaquinone), a compound derived from the root of the Plumbago zeylanica plant, was effective in selectively eliminating stringent, conjugative, multidrug-resistant plasmids from Escherichia coli strains.
Abstract: Plumbagin (5-hydroxy-2-methyl-1,4-naphthaquinone), a compound derived from the root of thePlumbago zeylanica plant, was effective in selectively eliminating stringent, conjugative, multidrug-resistant plasmids fromEscherichia coli strains. Simultaneous loss of resistance to antibiotics in plumbagin-treated cells indicated loss of plasmid. However, such R plasmids are refractory to treatment with acridine orange and sodium dodecyl sulfate, which are widely used in curing techniques.
TL;DR: The soil extract method revealed that recombinant DNA plasmids had no significant effect on survival of the Pseudomonas spp.
Abstract: A technique of potential use to the biotechnology industry was developed for studying the survival of bacteria in aqueous extracts of soil. The aqueous extracts of soil were placed into test tubes, amended as desired, inoculated with bacteria containing recombinant DNA, and incubated. Most bacteria introduced into filter-sterilized soil extracts were capable of multiplying and maintained populations of 10 E6 to 10 E8 cfu/ml over 13 days. However, bacteria introduced into nonsterile soil extracts at 10 E5 cfu/ml were found to decrease by 2–3 logs over a 13-day period. The soil extract method revealed that recombinant DNA plasmids had no significant effect on survival of thePseudomonas spp. andEscherichia coli strains examined. Extracts from soil provide a convenient and homogeneous milieu for estimating relative competitiveness and documenting survival characteristics of genetically engineered microorganisms. The use of aqueous extracts of soil offer convenience, a means of obtaining homogeneous cell suspensions, and ease of experimental replication over the inoculation of bacteria uniformly into soil.
TL;DR: When compared with a range of colonists of straw and other potential antagonists of glasshouse and cereal pathogens, Trichoderma harzianum IMI 275950 exhibited the greatest biocontrol activity in vitro.
Abstract: When compared with a range of colonists of straw and other potential antagonists of glasshouse and cereal pathogens,Trichoderma harzianum IMI 275950 exhibited the greatest biocontrol activity in vitro. This activity was also observed in a gnotobiotic lettuce bioassay against the pathogenSclerotinia sclerotiorum. Activity was dependent on antagonist/pathogen inoculum ratio and temperature.
TL;DR: Analysis of the secondary structure and hydropathic profile of the B TM protein indicates that alanine at this position increases both the propensity to form an α-helical structure and the hydrophobicity in the vicinity of this residue, indicating that the BTM toxin is potentially more cytolytic than the homologous protein of BTI.
Abstract: A gene encoding the 27.3 kilodalton cytolytic protein toxin in the mosquitocidal isolate (PG-14) ofBacillus thuringiensis subsp.morrisoni (BTM) was cloned and sequenced, and compared with the homologous gene inB. thuringiensis subsp.israelensis (BTI). The BTM gene was determined to be located on a 140 kb plasmid by use of a synthetic 20-base nucleotide probe derived from the sequence of the BTI gene. A 9.4-kbHind III plasmid fragment containing the BTM cytolytic protein gene was cloned into the plasmid vector pUC12, and subsequently subcloned and sequenced. Comparison of the nucleotide sequence of the BTM gene with that of the homologous BTI gene revealed only a single base difference; the base at position 310 in BTM is guanine, whereas in BTI it is cytosine. This single base change results in the occurrence of alanine rather than proline at amino acid residue 82 in BTM. Analysis of the secondary structure and hydropathic profile of the BTM protein indicates that alanine at this position increases both the propensity to form an α-helical structure and the hydrophobicity in the vicinity of this residue. Thus, the BTM toxin is potentially more cytolytic than the homologous protein of BTI.
TL;DR: A method has been developed, utilizing mutanolysin and proteinase K, for the rapid lysis of strains of the rumen cellulolytic bacterium Ruminococcus, which has enabled bacterial chromosomal and plasmid DNA to be isolated.
Abstract: A method has been developed, utilizing mutanolysin and proteinase K, for the rapid lysis of strains of the rumen cellulolytic bacteriumRuminococcus. This has enabled bacterial chromosomal and plasmid DNA to be isolated. A small cryptic plasmid has been identified inRuminococcus flavefaciens strain 186. It is 5.2 kb long, contains a singleBamHI site, and two sites forBglII,EcoRI, andHindIII. This plasmid has potential in the development of genetic vectors for rumen bacteria.
TL;DR: Cell proteins from the porcine mycoplasmasMycoplasma hyorhinis, M. hyopneumoniae, andM.
Abstract: Cell proteins from the porcine mycoplasmasMycoplasma hyorhinis, M. hyopneumoniae, andM. flocculare have been analyzed by SDS-gel electrophoresis and immunoblotting. The protein profiles ofM. hyopneumoniae andM. flocculare were similar, but the protein profile ofM. hyorhinis was quite different from the others. Antisera prepared against whole cells of the above three mycoplasmas were used in immunoblotting of electrophoretically separated antigens and in enzyme-linked immunosorbent assay. One major antigen, which had a molecular weight of 73 k, was found to be common to all three mycoplasmas. Another major antigen, with a molecular weight of 41 k, was common toM. hyopneumoniae andM. flocculare and may also be present inM. hyorhinis. Several antigens of comparatively high molecular weights (108 k, 102 k, 93 k, 89 k, and 87 k) seemed to be specific forM. hyopneumoniae. Three antisera prepared by immunization of rabbits with immunoprecipitates obtained by crossed immunoelectrophoresis ofM. hyopneumoniae were also used in blotting experiments. One of these antisera was found to be directed against the 73 k antigen common to the three porcine mycoplasmas investigated. The other two antisera were directed againstM. hyopneumoniae-specific antigens with molecular weights of 74 k, 58 k, 45 k, 44 k, and 38 k.
TL;DR: It is reported the pure-culture identification of a true mollicute, an Acholeplasma, that consistently associates with the larvae and adults of the marine bryozoan Watersipora arcuata, which represents the first confirmed nondisease association between a mollsicute and an aquatic invertebrate.
Abstract: Prokaryotes lacking a cell wall, formerly known as mycoplasmas were recently designated as the new class, Mollicutes. The association of unidentified “mycoplasma-like organisms” with aquatic animals has been suggested previously on the basis of visual observations alone. We report the pure-culture identification of a true mollicute, anAcholeplasma, that consistently associates with the larvae and adults of the marine bryozoanWatersipora arcuata. This represents the first confirmed nondisease association between a mollicute and an aquatic invertebrate.
TL;DR: The spores were more temperature-sensitive when formed in ethanol-supplemented media and may be that heat shock proteins, known to be induced by heat, are formed during sporulation and may increase the thermostability of the spores.
Abstract: Spores ofBacillus megaterium, B. subtilis, andB. stearothermophilus, harvested from cultures grown and sporulated at different temperatures or in the presence of ethanol, had different thermal resistance. There was a direct relationship between the sporulation temperature and the spore-killing temperature. The spores were more temperature-sensitive when formed in ethanol-supplemented media. Temperature and ethanol are known to perturb the degree of order within membranes and to alter membrane functions. Thus, alteration of spore membranes is an additional factor in the multifactorial nature of heat resistance. Another interpretation may be that heat shock proteins, known to be induced by heat, are formed during sporulation and may increase the thermostability of the spores.
TL;DR: The F&B medium proved to be the most for the detection of lysine decarboxylase, a positive test being highly correlated with the two species A. hydrophila and A. sobria, and it is suggested its use for routine detection of decar boxylase/dihydrolase activities.
Abstract: Decarboxylase/dihydrolase activities inAeromonas spp. are important as diagnostic tools and indicators of enterotoxin production. We have analyzed the following media at 25°C, 29°C, and 37°C, respectively, for their ability to detect such activities: Moller's, Falkow's, and Fay and Barry's (F&B) containing ornithine, lysine, and arginine, respectively, as well as motility-indole-ornithine (MIO) medium and lysine decarboxylase broth with 0.1% agar (LDC). In order to retain ornithine negativity, but to get as much positivity as possible for arginine, optimal incubation conditions were 29°C for 96 h (Moller), 48 h (Falkow, MIO, and LDC), and 24 h (F&B). The F&B medium proved to be the most sensitive for the detection of lysine decarboxylase, a positive test being highly correlated with the two speciesA. hydrophila andA. sobria, and we suggest its use for routine detection of decarboxylase/dihydrolase activities.
TL;DR: Growth characteristics of Deleya halophila, a bacterium with an absolute requirement for the Na+ cation, were determined using a defined medium and growth rates of the strain were diverse when NaCl was partially replaced by other sodium salts.
Abstract: Growth characteristics ofDeleya halophila (CCM 3662T), were determined using a defined mediumDeleya halophila presented its optimal growth at 75% (wt/vol) total salts when it was grwon at incubation temperatures of 32° and 42°C; when the temperature was lowered to 22°C, it had optimal growth at 5% (wt/vol) total salts This bacterium had an absolute requirement for the Na+ cation; it could not be replaced by other cations NaBr, Na2SO4, or Na2S2O3 could be substituted for NaCl in the growth medium, but, when MgCl2, KCl, LiCl, NaI, NaF, or NaNO3 was substituted for NaCl, the medium did not support growth Growth rates of the strain were diverse when NaCl was partially replaced by other sodium salts Finally,D halophila suffered loss of viability when the culture was diluted into different low NaCl concentrations (0, 05%, and 1%, wt/vol) at various incubation temperatures
TL;DR: Sixteen strains ofXanthomonas campestris pathovar (pv.) glycines produced bacteriocins (glycinecins) on agar media but they differed in their sensitivity to trypsin, deoxyribonuclease, and heat treatment.
Abstract: Sixteen strains ofXanthomonas campestris pathovar (pv.) glycines produced bacteriocins (glycinecins) on agar media. Optimal incubation conditions were for 48 h at 20°C. In addition to strains ofX. campestris pv. glycines, bacteriocins were also inhibitory towardsX. campestris pv. phaseoli andX. campestris pv. vesicatoria. All bacteriocins were susceptible to inactivation by a nonspecific protease and resistant to ribonuclease, but they differed in their sensitivity to trypsin, deoxyribonuclease, and heat treatment. Differential heat and enzyme sensitivities also indicated that some strains ofX. campestris pv. glycines produce more than one bacteriocin. Attempts to induce bacteriocin production in liquid cultures were unsuccessful. However, temperate bacteriophage were released from cultures ofX. campestris pv. glycines strains XP175, B83, 17915, and MINN after addition of mitomycin C or nalidixic acid or after exposure to UV light.