Ferrovibrio denitrificans gen. nov., sp. nov., a novel neutrophilic facultative anaerobic Fe(II)-oxidizing bacterium

A neutrophilic Fe(II)-oxidizing bacterium was isolated from the redox zone of a low-salinity spring in Krasnodar krai (Russia), at the FeS-Fe(OH)(3) interface deposited at the sediment surface. The cells of strain Sp-1 were short, thin motile vibrioids with one polar flagellum dividing by binary fission. The optimal values and ranges for pH and temperature were pH 6.2 (5.5-8) and 35?°C (5-45?°C), respectively. The organism was a facultative anaerobe. Strain Sp-1 was capable of organotrophic, lithoheterotrophic and mixotrophic growth with Fe(II) as an electron donor. The denitrification chain was 'disrupted'. Oxidation of Fe(II) was coupled to reduction of NO3 - to NO2 - or of N(2) O to N(2) , as well as under microaerobic conditions, with O(2) as an electron acceptor. The DNA G+C content was 64.2?mol%. According to the results of phylogenetic analysis, the strain was 10.6-12% remote from the closest relatives, members of the genera Sneathiella, Inquilinus, Oceanibaculum and Phaeospirillum within the Alphaproteobacteria. Based on its morphological, physiological and taxonomic characteristics, together with the results of phylogenetic analysis, strain Sp-1 is described as a member of a new genus Ferrovibrio gen. nov., with the type species Ferrovibrio denitrificans sp. nov. and the type strain Sp-1(T) (=?LMG 25817(T) =?VKM B-2673(T) ).     

An obligate halophilic bacterium from solar salt

Summary From pink solar salt an obligate halophilic bacterium was isolated and shown to be the cause of the pink discolaration. Method of isolation, cultural characteristics and nature of pigment are detailed. The bacterium proved to be closely related to previously described halophilic bacteria, andVolcani's suggestion that all such bacteria should form a genusHalobacterium seems acceptable. Further work however is indicated, especially as the present bacterium showed such unusual morphological features. Examined in the live state, by means of phase contrast microscopy, or preferably sunlight dark field methods, this bacterium usually did not present itself as a cylinder, but appeared flat as a ribbon, and in addition this ribbon often showed one or more twists (up to 180^c) per individual bacterium. This resulted in a spiral appearance of the bacterium, and its motility seemed to make use of this spiral configuration. Confirmation of this curious kind of morphology and motility was sought and found through the study of spiral glass models, and by means of cine-micrography¹). Flagella were not found. It is suggested, and there are some indications, that other bacteria of this group, and perhaps of other groups, might on similar examination in the live state, be found to show similar shapes.     

Characterization of a bacterium isolated from amber

A bacterium has been isolated from Baltic amber, after it was soaked in ethanol and flamed. The bacterium was a Gram-positive aerobic spore-forming rod whose 16S rDNA sequence had a 99.6% homology to that of Bacillus subtilis. Accordingly, the bacterium was identified as a strain in the species Bacillus subtilis. Considering the isolation procedure that was employed, the isolate should not be a contaminant of the contemporary Bacillus population; however, it may not be considered as a bacterium trapped when the amber was formed. These results suggest that amber might contain bacteria that were derived from the environments in which the amber had been located.     

V max per bacterium and turnover rate per bacterium for glucose mineralization in natural waters

Specific activity of aquatic bacteria, which indicates average heterotrophic activity per bacterial cell, was determined asV _max per bacterium and turnover rate per bacterium for glucose mineralization at different sites (river and estuary) in north Humberside, northeast England.V _max per bacterium ranged from 0.05×10⁻¹³ to 52.2×10⁻¹³ mg/h and turnover rate per bacterium from 0.05×10⁻⁸ to 88.3×10⁻⁸ ml/h. Highest mean values were found at river sites and the lowest at an outer estuary site, although there was considerable variation at each site and ranges from all sites overlapped. Also, ranges ofV _max per bacterium from Humberside sites in general overlapped published ranges for sites in other geographical areas.V _max per bacterium and turnover rate per bacterium were significantly correlated with some environmental variables, which suggests that they are of ecological significance.     

Metabolism of selenium in a selenium-dependent bacterium

A selenium-dependent Bacillus sp. is able to grow well up to 3% sodium selenite-containing media. The bacterium completely failed to grow on media devoid of selenium. The presence of selenium in the growth media increased the bacterial contents of proteins, carbohydrates, and lipids. The highest quantities of amino acids were detected at 2% sodium selenite-containing media. The bacterium metabolized selenite into several protein selenoamino acids such as selenomethionine and selenocysteine/selenocystine, as well as nonprotein selenoamino acids, such as selenocystathionine. Several phosphoamino acids were detected in the presence of elevated levels of selenium. The synthesized protein seems not to be affected by the presence of selenium.     

Isolation of a mercuric chloride-tolerant bacterium and uptake of mercury by the bacterium

Summary A mercuric chloride-tolerant bacterium was isolated from activated sludge and the bacterium was identified as Pseudomonas oleovorans.The bacterium is tolerant up to 350 ppm Hg²⁺, 100 ppm Cd²⁺, 40 ppm cr⁶⁺, and 1000 ppm Cu²⁺. Observation by scanning electron microscope of cells growing with mercury shows a less rigid structure of the cell surface than in the case of controls, while observation by transmission electron microscope shows many electron-dense granules in the cytoplasm of cells growing with mercury. By chemical analysis, about 80% of mercury taken up by the cells was found in the cytoplasm, and about 20% in the cell envelope fraction, of the resting cells used. Mercury was found in the supernatant fluid, but not in the microsomal fraction.Further detailed experiments for mercury distribution in the cells show that it is concentrated in the nucleic acid fraction of the supernatant fluid. In the insoluble fraction, mercury was found mainly in the polyphosphate-polysaccharide, mucopeptide, and lipopolysaccharide-polysaccharide fractions. In the case of the growing cells used, about 20% of the mercury was found in the cytoplasm and 80% in the insoluble fraction.     

Synthesis of collagenase by the phytopathogenic bacterium Corynebacterium rathayii

L abadie , J. 1990. Synthesis of collagenase by the phytopathogenic bacterium Corynebacterium rathayii. Journal of Applied Bacteriology 69 , 828–833.
The collagenase-producing bacterium tentatively called Empedobacter collagenolyti-cum was recently identified as Corynebacterium rathayii . Production of collagenase was studied in different media containing peptones or peptides of known sequences. A hexapeptide, Pro-Ala-Gly-Pro-Pro-Gly, is an inducer almost as good as collagen.     

A gas-producing marine bacterium

A gram-negative, aerogenic fermentative, marine bacterium is described and illustrated.     

The chemolithotrophic bacterium Thiobacillus ferrooxidans

Abstract: The iron-oxidizing bacterium ThiobaciUus ferrooxidans is the most important microorganism in mineral leaching. It plays the dominant role in bioextractive processes because of its ability to oxidize both iron and reduced sulfur compounds. T. ferrooxidans is also an important microorganism in acid rock/mine drainage, a serious environmental problem. In this article, the current status of this bacterium is described with particular emphasis on the biomining industry.     

Isolation and characterization of an anaerobic chlorophenol-transforming bacterium.

An obligately anaerobic bacterium which transforms several chlorinated phenols was isolated. Dechlorination of the substituents ortho to the phenolic OH group was preferred, while removal of a meta-substituted chlorine was observed only with 3,5-dichlorophenol. The bacterium was a gram-positive, endospore-forming, motile, slightly curved rod. Sulfate was not reduced. Nitrate was reduced via nitrite to ammonium. The bacterium is related to the genus Clostridium. The highest growth rate was obtained in a medium containing pyruvate and yeast extract. Pyruvate supported growth as the sole source of carbon, and the fermentation of pyruvate produced almost equimolar amounts of acetate.     

Pleomorphism of the marine bacterium Teredinobacter turnirae

AIMS: A morphology transition for the marine bacterium, Teredinobacter turnirae is reported. METHODS AND RESULTS: When grown in the rod-shaped morphology, the cells require high concentrations of NaCl (0.3 mol x l(-1)) and secrete extracellular protease and endoglucanase activity. When this bacterium is grown in a medium containing casein as a sole carbon and nitrogen source, a major change in morphology to a stable aggregated form is obtained. CONCLUSION: In the aggregated morphology, much higher protease production rates (170 Units x ml(-1) x d-1 for aggregates vs. 15 Units x ml(-1) x d(-1) for rods, for the same initial biomass) and negligible endoglucanase titres are obtained. In addition, the aggregated morphology does not require sodium chloride for growth. SIGNIFICANCE AND IMPACT OF THE STUDY: The phenomenon reported here describes a novel relationship between the cell morphology and the biochemical characteristics of the bacterium.     

Isolation and characterization of an anaerobic chlorophenol-transforming bacterium.

An obligately anaerobic bacterium which transforms several chlorinated phenols was isolated. Dechlorination of the substituents ortho to the phenolic OH group was preferred, while removal of a meta-substituted chlorine was observed only with 3,5-dichlorophenol. The bacterium was a gram-positive, endospore-forming, motile, slightly curved rod. Sulfate was not reduced. Nitrate was reduced via nitrite to ammonium. The bacterium is related to the genus Clostridium. The highest growth rate was obtained in a medium containing pyruvate and yeast extract. Pyruvate supported growth as the sole source of carbon, and the fermentation of pyruvate produced almost equimolar amounts of acetate.     

The nutritional selectivity of a siderophore-catabolizing bacterium

The ability of a siderophore-catabolizing bacterium to assimilate ferric ion was examined. While the bacterium utilizes the siderophore deferrioxamine B (DFB) as a carbon source, it was incapable of using the ferricion analogue (ferrioxamine B) as an iron source. It did, however, assimilate the ferric ion of the chelator ferric nitrilotriacetic acid and of the siderophore ferrirhodotorulic acid (ferriRA). Neither ferriRA nor its deferrated analog (RA), however, were capable of functioning as carbon sources for the bacterium. The microbe thus employs a nutritional selectivity with respect to these two siderophores. That is, it does not use the siderophore it employs as a carbon source (DFB) as an iron source nor does the siderophore utilized as an iron source, i.e. ferriRA, nor its deferrated analog (RA), serve as carbon sources for the organism.This paper is dedicated to the memory of Professor Thomas Emery. Professor Emery was instrumental in giving support and advice at a time when such mentorship greatly aided the corresponding author in developing a program concerning the catabolism of siderophores by microbes.     

Carotenoids of an Antarctic psychrotolerant bacterium, Sphingobacterium antarcticus, and a mesophilic bacterium, Sphingobacterium multivorum

The major carotenoid pigments of an Antarctic psychrotolerant bacterium, Sphingobacterium antarcticus, and a mesophilic bacterium, Sphingobacterium multivorum, were identified as zeaxanthin, beta-cryptoxanthin, and beta-carotene. Analysis was based on ultraviolet-visible spectroscopy, mass spectroscopy, and reversed-phase HPLC. Photoacoustic spectroscopy of intact bacterial cells revealed that the bulk of the pigments in S. antarcticus and S. multivorum was associated with the cell membrane. In vitro studies with synthetic membranes of phosphatidylcholine demonstrated that the major pigment was bound to the membranes and decreased their fluidity. The relative amounts of polar pigments were higher in cells grown at 5 degrees C than in cells grown at 25 degrees C. In the mesophilic strain, the synthesis of polar carotenoids was quantitatively less than that of the psychrotolerant strain.     

Starvation-survival of a p-nitrophenol-degrading bacterium.

An environmental actinomycetes, capable of utilizing p-nitrophenol as its sole carbon and nitrogen source, was starved for an 8-week period and showed no reduction in its ability to biodegrade p-nitrophenol. Microscopic examination revealed that starvation of the bacterium resulted in the fragmentation of filaments into individual cells.     

趋磁细菌研究进展

趋磁细菌的研究在我国起步较晚,也少见有相关报道,本文主要介绍国内外这一领域的研究进展,并提到了趋磁细菌在食品检测中的应用,旨在促进国内此工作的开展,以便更好的开发利用这一新的环境微生物资源,为食品检测方法的快速化多样化奠定基础。     

Spiral bacterium associated with gastric, ileal and caecal mucosa of mice.

A spiral shaped bacterium was seen in smears and histological sections (stained by carbolfuchsin) of gastric, ileal and caecal mucosa as well as in stool smears from mice. A significant correlation between the presence of the spiral bacterium and the occurrence of gastritis was observed but the ileal and caecal mucosa seemed unaffected. The bacterium was Gram negative and grew on BHM and Skirrow's medium, under microaerophilic conditions, at 37 degrees C. Its major biochemical characteristics included positive catalase and oxidase reactions and a rapidly positive urease test. There were 2 or 3 spiral turns per cell and a tuft of up to 12 sheathed flagella on each pointed end. Entwined, braided periplasmic fibrils covered the surface of the cell. This spiral bacterium seemed to be part of the normal intestinal flora but was associated with gastritis.     

棉花根际固氮菌、解磷菌及解钾菌的相互作用

目的通过对棉花根际促生细菌N2126、P1108和K2116菌株单独接种和混合接种,根据这些菌株的固氮、解磷、解钾能力和细胞数量的变化,了解它们之间的相互作用。方法将这3株菌株设置4个不同的组合:N2126+P1108、P1108+K2116、N2126+K2116及N2126+P1108+K2116,分别测定培养液中全氮含量,水溶性磷、钾含量和细胞数量。结果P1108对N2126的生长有促进作用但抑制K2116的生长,N2126和K2116之间存在拮抗作用。N2126、P1108和K2116混合培养后,三者细胞数量分别占培养液中细胞总数的6.4%、89.2%和4.4%;培养液中的全氮含量比不接种时下降了0.7%;水溶性磷、钾含量比不接种时分别增加了19.0%和12.2%。结论P1108为3株菌株混合培养时的优势菌株,3株菌株混合培养有助于磷、钾释放。     

A Pseudomonas viridiflava-related bacterium causes a dark-reddish spot disease in Glycine max

A virulent Pseudomonas viridiflava-related bacterium has been identified as a new pathogen of soybean, one of the most important crops worldwide. The bacterium was recovered from forage soybean leaves with dark-reddish spots, and damage on petioles and pods was also observed. In contrast, common bean was not affected.     

毒力岛与细菌致病性

毒力岛作为细菌染色体上一段具有典型结构特征的基因簇,与多种致病茵毒力因子的产生和细菌的进化有密切的关系,研究毒力岛对于认识致病细菌的变异,阐述病原菌的致病机理,预测新病原茵的出现有着十分重要的意义。