Ultrastructural observation on the bacterial capsule of Bacillus anthracis seen in the spleen of a diseased cow

The bacterial capsule of Bacillus anthracis seen in the spleen of a cow which had died of anthrax was studied electron microscopically. It was visible around bacteria which had been fixed in a ruthenium red-containing fixative. It was composed of electron-dense spikes and extended outwards from the bacterial surface. It was not found around bacteria which had been treated with a fixative devoid of ruthenium red. Bacteria were seen scattered among blood cells. They were not phagocytized by neutrophils or macrophages.     

黄缘盒龟细菌性感染的观察

利用电子显微镜,对一只濒死黄缘盒龟的心、肝、脾、肺、肾、胃和肠道进行了检查,在心、肝、脾、肾均发现一种短杆状细菌感染,受染器官均出现明显的病理变化,如线粒体、高尔基体和内质网均肿大变形. 肺部虽未找到细菌,但发现有明显的病变存在,如细支气管的微绒毛脱落,并可见坏死区. 胃和肠道未发现细菌感染,未见明显的病理改变.     

Diversity of prokaryotes and methanogenesis in deep subsurface sediments from the Nankai Trough, Ocean Drilling Program Leg 190

Diversity of Bacteria and Archaea was studied in deep marine sediments by PCR amplification and sequence analysis of 16S rRNA and methyl co-enzyme M reductase (mcrA) genes. Samples analysed were from Ocean Drilling Program (ODP) Leg 190 deep subsurface sediments at three sites spanning the Nankai Trough in the Pacific Ocean off Shikoku Island, Japan. DNA was amplified, from three depths at site 1173 (4.15, 98.29 and 193.29 mbsf; metres below the sea floor), and phylogenetic analysis of clone libraries showed a wide variety of uncultured Bacteria and Archaea. Sequences of Bacteria were dominated by an uncultured and deeply branching 'deep sediment group' (53% of sequences). Archaeal 16S rRNA gene sequences were mainly within the uncultured clades of the Crenarchaeota. There was good agreement between sequences obtained independently by cloning and by denaturing gradient gel electrophoresis. These sequences were similar to others retrieved from marine sediment and other anoxic habitats, and so probably represent important indigenous bacteria. The mcrA gene analysis suggested limited methanogen diversity with only three gene clusters identified within the Methanosarcinales and Methanobacteriales. The cultivated members of the Methanobacteriales and some of the Methanosarcinales can use CO2 and H2 for methanogenesis. These substrates also gave the highest rates in 14C-radiotracer estimates of methanogenic activity, with rates comparable to those from other deep marine sediments. Thus, this research demonstrates the importance of the 'deep sediment group' of uncultured Bacteria and links limited diversity of methanogens to the dominance of CO2/H2 based methanogenesis in deep sub-seafloor sediments.     

The first lines of divergence in the Bacteria domain seem to be the hyperthermophilic organisms: a check using an outgroup of sequences from mesophiles in phylogenetic analysis

We have conducted a check by substituting, in a previous phylogenetic analysis, an outgroup of sequences from hyperthermophilic archaea with another of mesophilic sequences of archaea. This should remove a possible compositional bias which might be responsible for the deep position of Thermotogales and Aquificales in the Bacteria domain, as observed in previous analyses. This check brought to light a weak compositional bias which does not seem, however, to entirely explain the deep position occupied by hyperthermophilic bacteria. The present analysis also seems to show that Planctomycetes are one of the deepest lines of divergence in the Bacteria domain, although they do not seem to be the very deepest.     

Influence of the introduction of Caragana arborescens on the composition of its root-nodule bacteria

The genetic diversity and phylogeny of root module bacteria entering into symbiotic relations with Caragana arborescens introduced on the territory of the Republic of Bashkortostan (RB) were studied. Analysis of the 85 strains isolated from root-nodules showed that, according to the DNA polymorphism revealed by RAPD analysis, they can be divided into 12 groups. It was found that, both in natural habitats and on the territory of the RB, Caragana arborescens is primarily nodulated by Mesorhizobium bacteria whose 16S rRNA gene sequences differ to some degree from those of the bacteria described earlier by Chinese authors. Bacteria assigned to the genus Phyllobacterium based on their 16S rRNA gene sequences were also revealed in plants growing on the territory of the RB.     

Taxonomic and functional diversity of pseudomonads isolated from the roots of field-grown canola

Among the most important rhizosphere bacteria are the pseudomonads, which are aggressive colonizers and utilize a wide range of substrates as carbon sources. The objective of this study was to determine if the taxonomic or metabolic diversity of pseudomonads differed among field-grown canola cultivars. Bacteria (n=2257) were isolated from the rhizosphere and root interior of six cultivars of field-grown canola, including three transgenic varieties. The bacteria were identified by fatty acid methyl ester (FAME) analysis, and about 35% were identified as Pseudomonas species. The most abundant species were Pseudomonas putida and Pseudomonas chlororaphis. Dendrograms based on FAME analysis revealed that many pseudomonad strains were found in all of the canola cultivars. Pseudomonads of the same strain were found in both the rhizosphere and the root interior of canola plants, suggesting that endophytic bacteria were a subset of the rhizosphere community. Because metabolic profiling provides more useful information than taxonomy, P. putida and P. chlororaphis isolates were characterized for their ability to utilize carbon substrates and produce several enzymes. Bacteria isolated from different plant cultivars had different carbon utilization profiles, but when only carbon substrates found in root exudates were analyzed, the cultivar effect was less pronounced. These characterizations also demonstrated that bacteria that were determined by FAME to be the same strain were metabolically different, suggesting functional redundancy among Pseudomonas isolates. The results of this study suggest that pseudomonads were functionally diverse. They differed in their metabolic potential among the canola cultivars from which they were isolated. Because bacteria capable of using many substrates can effectively adapt to new environments, these results have implications for the use of pseudomonads as biofertilizers, biological control agents and plant growth-promoting bacteria in canola.     

Aerobic bacterial flora from the digestive tract of the common vampire bat, Desmodus rotundus (Chiroptera: Phyllostomidae)

This study addresses the composition of microbial flora in the vampire bat (Desmodus rotundus) primarily because all available data are outdated, and because of the economical significance of this bat species. Twenty-one bats were collected and their aerobic bacteria documented separately for stomach and intestine. Bacteria were identified through the Analytical Profile Index (API), and results analyzed with the APILAB software. A total of thirty bacterial species were isolated from sixteen females and five males. The most common species were Escherichia coli and Staphylococcus aureus, although other bacteria, such as Acinetobacterjohnsonii, Enterobacter sakazakii, Staphylococcus chromogenes, S. hyicus and S. xylosus were also common. The number of species found in the stomach and intestine was significantly different, and the intestine presented a higher diversity compared to the stomach. This has previously been found in other mammals and it is attributed to a reduction of acidity. Most of the species found in this study are considered normal components of the digestive tract of mammals, although other bacteria common in the skin of mammals and from aquatic environments were found. Bacteria from the skin may invade the vampire's stomach and/or intestine when the bat has contact with its prey, and may suggest that the vampire's feeding habit facilitates the invasion of other microbes not common in its digestive tract. The fact that bacteria from aquatic environments were also found suggests that D. rotundus, as previously found by other researchers, drinks free water when available, and water may be another source of microbial invasion.     

Prokaryotic community composition and biogeochemical processes in deep subseafloor sediments from the Peru Margin

The community compositions of Bacteria and Archaea were investigated in deep, sub-seafloor sediments from the highly productive Peru Margin (ODP Leg 201, sites 1228 and 1229, c. 25 km apart) down to nearly 200 m below the seafloor using taxonomic (16S rRNA) and functional (mcrA and dsrA) gene markers. Bacterial and archaeal groups identified from clone libraries of 16S rRNA gene sequences at site 1229 agreed well with sequences amplified from bands excised from denaturing gradient gel electrophoresis (DGGE) depth profiles, with the exception of the Miscellaneous Crenarchaeotic Group (MCG). This suggested that the prokaryotic community at site 1228, obtained from DGGE profiling alone, was reliable. Sites were dominated by Bacteria in the Gammaproteobacteria, Chloroflexi (green non-sulphur bacteria) and Archaea in the MCG and South African Gold Mine Euryarchaeotic Group, although community composition changed with depth. The candidate division JS1 was present throughout both sites but was not dominant. The populations identified in the Peru Margin sediments consisted mainly of prokaryotes found in other deep subsurface sediments, and were more similar to communities from the Sea of Okhotsk (pelagic clays) than to those from the low organic carbon Nankai Trough sediments. Despite broad similarities in the prokaryotic community at the two sites, there were some differences, as well as differences in activity and geochemistry. Methanogens (mcrA) within the Methanosarcinales and Methanobacteriales were only found at site 1229 (4 depths analysed), whereas sulphate-reducing prokaryotes (dsrA) were only found at site 1228 (one depth), and these terminal-oxidizing prokaryotes may represent an active community component present at low abundance. This study clearly demonstrates that the deep subsurface sediments of the Peru Margin have a large diverse and metabolically active prokaryotic population.     

Bacteriologic studies of bovine genital tracts: The use of dye as an indicator of postmortem contamination of the uterus by vaginal fluids

Non-specific bacteria were more frequently isolated from uteri of culled dairy cattle than beef cows (P <.01). In some studies, food dye was placed in the vagina just prior to slaughter as an indicator of postmortem contamination of the uterus by vaginal fluids and bacteria. The dye was more often found in the uteri of dairy cows than beef cows (P <0.05).Bacteria could always be isolated from uteri totally contaminated by the dye. Bacteria were more frequently isolated from uncontaminated areas of uteri that were partially contaminated by the dye, as compared to uteri in which no dye was found (P <.01).It is hypothesized that an enlarged cervical canal may allow dye and also bacteria to transverse the cervical canal into the uterus during the slaughtering process. It is further hypothesized that an enlarged cervical canal may more readily permit nonspecific bacteria of the vagina to ascend into the uterus in the live animal and cause reproductive failure.     

A bacteria-induced switch of sympathetic effector mechanisms augments local inhibition of TNF-alpha and IL-6 secretion in the spleen.

It is believed that an inflammation-induced activation of the CNS leads to an inhibition of overshooting immune responses to prevent extensive local cytokine secretion. However, immunosuppression by the sympathetic nervous system may be unfavorable when bacteria are present locally and when TNF-alpha is necessary to overcome infection. We now report in a superfusion model, using mouse spleen slices, that although local Pseudomonas aeruginosa increased splenic TNF-alpha and IL-6 secretion severalfold over basal levels, electrically released neurotransmitters attenuated cytokine secretion to similar basal level as under bacteria-free conditions. Bacteria reversed noradrenergic inhibitory effector mechanisms: Under bacteria-free conditions, TNF-alpha secretion was very low and IL-6 secretion was mainly inhibited by alpha2-adrenoreceptor ligation. In the presence of bacteria, TNF-alpha and IL-6 secretion were high and IL-6 secretion was mainly inhibited by beta-adrenoreceptor ligation. The alpha- to beta-adrenoswitch of IL-6 inhibition in the presence of bacteria was mediated by the prior adrenergic regulation of TNF-alpha. In vivo, chemical abrogation of sympathetic inhibition reduced accumulation of bacteria in the spleen, which depended at least in part on TNF-alpha. This suggests that activation of the sympathetic nervous system may be a forerunner for accumulation of bacteria in tissue and consecutively sepsis due to intensified inhibition of TNF-alpha secretion.     

北极表层海水中氯代十六烷降解菌的多样性

[目的]为了研究北极地区表层海水中氯代十六烷(C16H33Cl)降解菌的多样性,并获得新的卤代烃降解菌资源.[方法]以C16H33Cl为唯一碳源和能源在4℃和250℃下对表层海水样品进行富集,通过平板分离鉴定可培养菌株,并验证其降解能力;同时利用变性梯度凝胶电泳(DGGE)分析降解菌群结构.[结果]从12个北极表层海水样品中富集分离得到112株可培养菌株.经过降解实验验证,发现19株菌株能够降解氯代十六烷,其中食烷菌(Alcanivorax)、红球菌(Rhodococcus)表现出很好的乳化和降解现象,海杆菌(Marinobacter)也有较好的降解效果.DGGE分析显示,富集驯化的降解菌群中主要优势菌为Alcanivorax,Parvibaculum和Thioclava属的菌株.[结论]北极海水中卤代烃降解菌主要是α-proteobacteria,γ-proteobacteria,Actinobacteria和Bacteroidetes.文章首次报道了北极海水卤代烷烃降解菌多样性,研究结果对于认识北极环境中的降解菌资源与生物多样性有参考价值.     

Bacteriology of Manganese Nodules: I. Bacterial Action on Manganese in Nodule Enrichments

Bacteria, found in manganese nodules from the Atlantic Ocean, enhance the adsorption of Mn from sea water by crushed manganese nodules in the presence of peptone. When bacterial outgrowth from crushed manganese nodules was experimentally delayed, peptone did not enhance Mn adsorption by nodular substance, but hindered it in some cases. A mechanism to explain the role of bacteria in enhancing Mn adsorption by manganese nodules is presented. Oyster shells were shown to adsorb Mn in the absence of bacteria. Peptone did not enhance the rate of Mn adsorption. Adsorbed Mn was not visibly oxidized during experimental observation. These results suggest one way whereby nodule formation may be initiated in the oceans. Some bacteria in the nodules were found to release manganese from them in the presence of glucose and peptone. Bacteria may, therefore, play a role not only in nodule buildup but also in nodule breakdown.     

The effects of the presence of stored product pests on the microfauna of a flour community

AIMS: To determine the effect that the presence of some beetles have on the species of bacteria found in their flour. METHODS AND RESULTS: Bacteria were isolated from flour that either did not contain beetles, contained Tribolium beetles in different environments, or contained either Stegobium paniceum or Lasioderma serricorne. These bacteria were tentatively identified by both the gas chromatography-fatty acid methyl esters (GC-FAME) method and partial sequencing of the 16S rRNA gene. All samples contained Bacillus species including the controls, but the non-Tribolium beetles and a Tribolium beetle line known to have low benzoquinones also contained Enterococcus and Enterobacter species. Additionally an unidentified bacteria isolate in the Enterobacteriaceae was also found in the L. serricorne sample. Our results also suggest incongruent identifications when using the GC-FAME method vs sequencing. CONCLUSIONS: Certain species of bacteria can be introduced by the presence of insect pests, but the diversity of species is far less in stocks of Tribolium beetles. SIGNIFICANCE AND IMPACT OF THE STUDY: Stored product pests can alter the bacterial community. Isolated species from this study show a strong genetic relationship to each other, suggesting an isolated evolving system. A unique bacteria was also isolated. GC and sequencing methods of identification are compared.     

Inactivating action of bacteria on the lipolytic activity of solizyme and its prevention by antibacterial drugs]

Bacteria capable of producing exoproteases were isolated from intermediate products of microbial lipase. The proteolytic enzymes produced by the bacteria were able to inactivate 20 to 80 per cent of the lipase depending on the time of incubation, protease production by the contaminating microbe and the experimental conditions. Antibiotics and antiseptics inhibiting growth of bacteria prevented or limited their inactivating action on lipase. Except catamine, the tested antimicrobial drugs as such had no effect on lipase activity.     

Tissue distribution and cellular distribution of liposomes encapsulating muramyltripeptide phosphatidyl ethanolamide

In previous studies it was shown that administration of liposome-encapsulated MTPPE (LE-MTPPE) led to resistance againstKlebsiella pneumoniae infection. To get more insight in the cell types that are involved in this by LE-MTPPE induced antibacterial resistance, the tissue distribution of liposomes encapsulating MTPPE and the distribution over the cells in the main target organs were investigated. After intravenous injection of the liposomes in mice a substantial amount was recovered from liver and spleen and a smaller amount from the lung. In the liver 83% of the liposomes was taken up by the macrophages. In the spleen also most liposomes were taken up by macrophages of the red and white pulp as well as by dendrocytes. The liver and spleen were also the organs in which, after intravenous inoculation,K. pneumoniae was trapped. It was observed that cells containing LE-MTPPE often had not taken up bacteria. Most bacteria, about 73%, were found in cells not containing liposomes. The capacity of the liposome-containing cells to take up bacteria did not change with time. This suggests that the by LE-MTPPE immunostimulating effect is due to the production of cytokines by the cells that take up LE-MTPPE. These cytokines might stimulate other cells to the killing of bacteria.     

Potential for bioremediation of fuel‐contaminated soil in Antarctica

A preliminary investigation was conducted to identify the presence of bacteria in fuel‐contaminated Antarctic soil that could potentially be used to bioremediate the contaminated soil at McMurdo Station and other sites in Antarctica. The ability of soil microorganisms to metabolize fuels under the extreme climatic and oligotrophic conditions of Antarctica was of concern. Bacteria were isolated from fuel‐contaminated soil on site at McMurdo Station. Bacteria from noncontaminated soil near the station were also studied for comparison. The Antarctic soil microorganisms exhibited the ability to endure cold and oligotrophic environments. Experiments also showed that bacteria from the fuel spill site were active in their contaminated environment and that acclimation to xenobiotic compounds was necessary. Application of bioremediation in the extreme environmental conditions found at McMurdo Station, Antarctica, were also considered. The possibility of altering environmental factors necessary to adequately support in situ bioremediation in this extreme climate is discussed.     

Endosymbiotic bacteria associated with the intracellular green algae ofHydra viridis

Gram-negative bacteria 4.5–5.5 μm in length and 1.2 μm in diameter are found in gastrodermal cells of three stains of freshwater green hydras,Hydra viridis (Ohio and Carolina from North America, Jubilee strain from England). They are motile via single polar flagella. They were detected in live animals, Jensen stained material, and electron micrographic sections. Bacteria lose motility quickly upon release from hydra cells. Green hydras harbor strain-specific numbers of chlorellae in these cells. Other tissue types lack algae. The chlorella-hydra symbiosis can be disassociated and the partners grown separately; transfer of photosynthate from algae to hydra occurs. Here we report the presence of endocellular bacterial vesicles specifically associated with cells that contain the symbiotic chlorellae. No cells that contained algae and lacked bacteria were seen. Vesicles, especially conspicuous in sexually mature green hydras, are probably produced upon extrusion from the cell. They contain either algae and bacteria or bacteria alone and are often expelled to the surrounding medium via the coelenteron. Bacteria are absent in nerve cells, interstitial cells, nematocysts, mucous cells, sperm, and probably in most of the other cell types that lack algae. They are present in at least one cell type that lacked algae: the columnar ovarian cells. Bacteria were lost in “bleached” hydras, those induced to lose their algae by high intensity light in a solution of DCMU, a standard inhibitor of photosynthesis. They were absent in a fourth strain of green hydra (Connecticut Valley,H. viridis) and inH. fusca andH. littoralis, two freshwater nonsymbiotic hydras. All of the hydra lacking bacteria contain conspicuous lipid droplets in their cells. The presence of large numbers of bacteria has implications for interpretations of metabolic exchange between host and algal symbionts and for extrapolation of metabolic data from strain to strain ofH. viridis.     

Co-metabolism of the Ixodicide Amitraz

Bacteria capable of degrading the ixodicide amitraz were isolated from cattle dipping tanks by the enrichment culture technique. The conditions for amitraz degradation were characterized and the bacteria identified as Pseudomonas and Achromobacter spp. The bacteria degraded amitraz without utilizing the ixodicide as a substrate or energy source. The degradation of amitraz by bacteria is an example of co-metabolism with yeast extract or an ingredient of yeast extract acting as the co-metabolite. Bacteria were unable to degrade amitraz at pH >11.5. Although bacteria can degrade amitraz, it is giving excellent tick control under practical field conditions.     

急性化脓性骨髓炎患者病原菌分布及耐药性分析

目的:分析急性化脓性骨髓炎患者病原菌的分布特点及耐药情况。方法:取急性化脓性骨髓炎患者窦道深部分泌物或病灶组织做细菌培养及药敏试验。结果:80例患者共培养出病原菌18种110株:其中7例同时培养出3种细菌,15例同时培养出2种细菌,58例培养出1种细菌。110株细菌中,革兰氏阳性(G+)菌55株,占50.0%,主要为金黄色葡萄球菌14株,占25.5%;革兰氏阴性(G-)菌52株,占47.3%,主要为铜绿假单胞菌13株,占25.0%。真菌3株,占2.7%。金黄色葡萄球菌对抗菌药物万古霉素最敏感,耐药率为7.1%,对青霉素耐药率最高,耐药率为92.9%;铜绿假单胞菌对抗菌药物头孢哌酮最敏感,耐药率为7.7%,对亚胺培南的耐药率最高,为92.3%。结论:化脓性骨髓炎的致病菌中革兰氏阳性菌和革兰氏阴性菌的的占比基本持平,大多数病原菌对常用的抗菌药物均具有耐药性。     

Scanning Electron Microscopic Observation of Differentiation from the Reproductive Short Form to the Infectious Long Form of Holospora obtusa

To identify the surface features of Holospora obtusa during its differentiation from the reproductive short form to the infectious long form, bacteria of four different buoyant densities were isolated by Percoll density gradient centrifugation of homogenates of host cells or isolated macronuclei, and examined with a scanning electron microscope. Bacteria of buoyant density 1.09 g/ml were reproductive short forms as well as cells at various stages in the elongation process including fully elongated ones. Bacteria of buoyant densities 1.11 g/ml and 1.13 g/ml were premature long forms and those of 1.16 g/ml were mature infectious long forms. Bacteria of buoyant density 1.09 g/ml had an entirely rough surface while those of buoyant densities 1.11 g/ml and 1.13 g/ml were smooth and had wale-like stripes on their surface. A small tapered tip was observed at one end of the bacteria of buoyant density 1.13 g/ml. Bacteria of buoyant density 1.16 g/ml had an entirely smooth surface, but one end always showed a rough surface; this locally differentiated surface of the special tip of the infectious long form may be responsible for both the nuclear and species specificities of the infectivity of H. obtusa. These observations indicate that the surface of H. obtusa changes during differentiation and the special tip develops in bacteria of buoyant density 1.13 g/ml.