Volatile organic compounds produced by a soil-isolate, Bacillus subtilis FA26 induce adverse ultra-structural changes to the cells of Clavibacter michiganensis ssp. sepedonicus, the causal agent of bacterial ring rot of potato.

Rhizobacterial volatile organic compounds (VOCs) play an important role in the suppression of soil-borne phytopathogens. In this study, the VOCs produced by a soil-isolate, Bacillus subtilis FA26, were evaluated in vitro for their antibacterial activity against Clavibacter michiganensis ssp. sepedonicus (Cms), the causal agent of bacterial ring rot of potato. The VOCs emitted by FA26 inhibited the growth of Cms significantly compared with the control. Scanning and transmission electron microscopy analyses revealed distorted colony morphology and a wide range of abnormalities in Cms cells exposed to the VOCs of FA26. Varying the inoculation strategy and inoculum size showed that the production and activity of the antibacterial VOCs of FA26 were dependent on the culture conditions. Headspace solid-phase microextraction/gas chromatography-mass spectrometry analyses revealed that FA26 produced 11 VOCs. Four VOCs (benzaldehyde, nonanal, benzothiazole and acetophenone) were associated with the antibacterial activity against Cms. The results suggested that the VOCs produced by FA26 could control the causal agent of bacterial ring rot of potato. This information will increase our understanding of the microbial interactions mediated by VOCs in nature and aid the development of safer strategies for controlling plant disease.

Draft genome of the emerging pathogen, Kocuria marina, isolated from a wild urban rat.

Kocuria marina has recently emerged as a cause for catheter-related bloodstream infections in patients with underlying health complications. One K. marina strain was recently isolated from the lung tissues of a wild urban rat (Rattus rattus diardii) caught during rodent surveillance. Here, we present the draft genome of the first K. marina animal isolate, K. marina TRE150902.

Removal of multi-heavy metals using biogenic manganese oxides generated by a deep-sea sedimentary bacterium - Brachybacterium sp. strain Mn32.

A deep-sea manganese-oxidizing bacterium, Brachybacterium sp. strain Mn32, showed high Mn(II) resistance (MIC 55 mM) and Mn(II)-oxidizing/removing abilities. Strain Mn32 removed Mn(II) by two pathways: (1) oxidizing soluble Mn(II) to insoluble biogenic Mn oxides - birnessite (delta-MnO(2) group) and manganite (gamma-MnOOH); (2) the biogenic Mn oxides further adsorb more Mn(II) from the culture. The generated biogenic Mn oxides surround the cell surfaces of strain Mn32 and provide a high capacity to adsorb Zn(II) and Ni(II). Mn(II) oxidation by strain Mn32 was inhibited by both sodium azide and o-phenanthroline, suggesting the involvement of a metalloenzyme which was induced by Mn(II). X-ray diffraction analysis showed that the crystal structures of the biogenic Mn oxides were different from those of commercial pyrolusite (beta-MnO(2) group) and fresh chemically synthesized vernadite (delta-MnO(2) group). The biogenic Mn oxides generated by strain Mn32 showed two to three times higher Zn(II) and Ni(II) adsorption abilities than commercial and fresh synthetic MnO(2). The crystal structure and the biogenic MnO(2) types may be important factors for the high heavy metal adsorption ability of strain Mn32. This study provides potential applications of a new marine Mn(II)-oxidizing bacterium in heavy metal bioremediation and increases our basic knowledge of microbial manganese oxidation mechanisms.

Atypical growth of Renibacterium salmoninarum in subclinical infections.

Two growth types of Renibacterium salmoninarum were isolated from subclinically infected rainbow trout, one producing the smooth colonies typical of R. salmoninarum and the other forming a thin film on the surface of the agar with no separate colonies. The atypical growth was present on kidney disease medium agar in primary cultures of the kidney but not on selective kidney disease medium (SKDM). Fluorescent antibody staining of the fresh isolate and polymerase chain reaction amplification were the most reliable techniques to identify the atypical growth of R. salmoninarum. The condition was reversible, with growth reverting from atypical to the smooth colony form in experimentally infected rainbow trout and under laboratory conditions. There was no mortality, or any clinical signs of bacterial kidney disease (BKD) in the fish challenged with the atypical growth, although small numbers of smooth colonies of R. salmoninarum were isolated from 8% of these fish. The atypical growth reported here may explain some of the failures of culture, when SKDM agar alone is used for the detection of BKD in subclinically infected fish.

Renibacterium salmoninarum bar forms: characterization, occurrence, and evidence of a host response to a R. salmoninarum infection.

Unique-staining Renibacterium salmoninarum (Rs) cells, termed bar forms, first observed in a coho salmon, Oncorhynchus kisutch (Walbaum), in 1983, could not be cultured, making their characterization difficult and significance obscure. They can be detected only by the fluorescent-antibody technique (FAT) and their numbers estimated only by a quantitative FAT (QFAT). Data collected over a 10-year period showed that bar forms were observed only in vivo and appeared associated with a host response. Bar forms were observed in 10 salmonid species from five countries and in fish from < 1 g to spawning adults. They were observed in 50.1% of kidney smears prepared from 10,061 Rs positive chinook, O. tshawytscha (Walbaum), coho, and Atlantic salmon, Salmo salar L. Bar forms were shown to be Rs cells based on absorption studies, their reaction with an Rs-specific FAT and enzyme-linked immunosorbent assay, and a transition from 'typical' Rs cells to bar forms in naturally and experimentally infected fish. Bar forms were determined to be non-virulent, damaged or dead Rs cells, based on fluorescence and electron microscopy observations, the inability to culture them, and mortality data. Bar forms appeared to represent visual markers of recovery from an Rs infection.

Isolation of Stomatococcus mucilaginosus from drug user with endocarditis.

Stomatococcus mucilaginosus was isolated from the blood of a patient with endocarditis and a past history of drug abuse and aortic valve replacement. At autopsy, Gram stain of the aortic valve revealed gram-positive cocci. Our isolate was atypical for S. mucilaginosus in that colonies were nonmucoid and nonadherent to agar surfaces. Cellular capsules were demonstrated by light and electron microscopy. Phenotypic characteristics identified by conventional methods as well as profile numbers obtained by using two commercial identification systems for staphylococci, the API Staph-Ident and the dms Staph Trac, are presented. Practical tests that differentiate S. mucilaginosus from the genera Micrococcus and Staphylococcus include growth on nutrient agar containing salt and lysostaphin susceptibility. Additional tests that helped differentiate our isolate from group D streptococci included hydrolysis of L-pyrrolidonyl-beta-naphthylamide and streptococcal serogrouping.

Comparative ultrastructure of methanogenic bacteria.

Electron-microscopic studies using thin sections revealed that methane-producing bacteria were an ultrastructurally diverse group. Fine structure and morphological characteristics separated these bacteria into four discrete cell types. Methanogenic bacteria displayed a gram-positive cell wall that varied considerably among different cell types. Differences in granular inclusions, reserve materials, and intracytoplasmic membranes were observed. Unique ultrastructural features were not shared by all methanogenic species studies.

[Sebaceous filaments (author's transl)]. / Follikel-Filamente

Sebaceous filaments are cylindrical tubes of whitish-yellowish color, which can be expressed from areas of the face rich in sebaceous follicles by pinching the skin or by the cyanoacrylat-technique. Sebaceous filaments are most commonly found in the centrofacial areas and the alae nasae in postpuberal individuals with large facial pores and seborrhea. Sebaceous filaments are composed of a skeleton of 10-30 horny cell layers which enclose a mixture of bacteria, sebaceous lipid, corneocyte fragments and one hair. Following the expression of the filament the follicle refills within 30 days. The various portions of sebaceous follicles (acro- and infrainfundibulum) and the follicular contents are presented at the light microscopial and ultrastructural level. Follicles containing sebaceous filaments have a conspicuous granular layer and no acanthosis. Sebaceous filaments should be differentiated from a microcomedo and trichostasis spinolosa. They are a common morphological variant of sebaceous follicles.

Na+-induced structural change of a soil bacterium, S34, and Ca2+ requirement for preserving its original structure.

A drastic change in the outer membrane structure of a salt-sensitive soil bacterium, S34, related to the genus Deinococcus was induced by 0.2 to 0.4% (wt/vol) NaCl. The change was relieved by 6 mM CaCl2 and induced by 1 mM EGTA. The results indicate the strong dependence of the organism on calcium.

Pair-dependent co-aggregation behavior of non-flocculating sludge bacteria.

Two strains of non-flocculating sewage sludge bacteria (Xanthomonas sp. S53 and Microbacterium esteraromaticum S51) showed 91% and 77% co-aggregation, respectively, with Acinetobacter johnsonii S35 using a spectrophometric assay. The co-aggregates in case of Xanthomonas sp. S53 and A. johnsonii S35 were above 100 microm and stable against EDTA (2 mM) and a commercial protease (0.2 mg ml(-1)). Protease/periodate pretreatment of the partners did not affect this co-aggregation. On the other hand, co-aggregates of M. esteraromaticum S51 and A. johnsonii S35 (50-70 microm) were deflocculated by EDTA or protease. Protease pretreatment of M. esteraromaticum S51 and periodate pretreatment of A. johnsonii S35 prevented their co-aggregation with respective untreated partners. The potential co-aggregation mechanisms of A. johnsonii S35 varied depending upon the other partner involved.