During attempts to obtain novel, human-associated species of the domain Archaea , a coccoid micro-organism, designated strain B10T, was isolated in pure culture from a sample of human faeces collected in Marseille, France. On the basis of its phenotypic characteristics and 16S rRNA and mcrA gene sequences, the novel strain was classified as a methanogenic archaeon. Cells of the strain were non-motile, Gram-staining-positive cocci that were approximately 850 nm in diameter and showed autofluorescence at 420 nm. Cells were lysed by 0.1 % (w/v) SDS. With hydrogen as the electron donor, strain B10T produced methane by reducing methanol. The novel strain was unable to produce methane when hydrogen or methanol was the sole energy source. In an atmosphere containing CO2, strain B10T could not produce methane from formate, acetate, trimethylamine, 2-butanol, 2-propanol, cyclopentanol, 2-pentanol, ethanol, 1-propanol or 2,3-butanediol. Strain B10T grew optimally with 0.5–1.0 % (w/v) NaCl, at pH 7.6 and at 37 °C. It required tungstate-selenite for growth. The complete genome of the novel strain was sequenced; the size of the genome was estimated to be 2.05 Mb and the genomic DNA G+C content was 59.93 mol%. In phylogenetic analyses based on 16S rRNA gene sequences, the highest sequence similarities (98.0–98.7 %) were seen between strain B10T and several uncultured, methanogenic Archaea that had been collected from the digestive tracts of a cockroach, a chicken and mammals. In the same analysis, the non-methanogenic ‘Candidatus Aciduliprofundum boonei’ DSM 19572 was identified as the cultured micro-organism that was most closely related to strain B10T (83.0 % 16S rRNA gene sequence similarity). Each of the three treeing algorithms used in the analysis of 16S rRNA gene sequences indicated that strain B10T belongs to a novel order that is distinct from the Thermoplasmatales . The novel strain also appeared to be distinct from Methanosphaera stadtmanae DSM 3091T (72.9 % 16S rRNA gene sequence similarity), another methanogenic archaeon that was isolated from human faeces and can use methanol in the presence of hydrogen. Based on the genetic and phenotypic evidence, strain B10T represents a novel species of a new genus for which the name Methanomassiliicoccus luminyensis gen. nov., sp. nov. is proposed. The type strain of the type species is B10T ( = DSM 24529T = CSUR P135T).

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A strictly anaerobic thiosulfate-reducing bacterium was isolated from a corroding offshore oil well in Congo and was designated strain SEBR 4207T. Pure culture of the strain induced a very active pitting corrosion of mild steel, with penetration rates of up to 4 mm per year. This constitutes the first experimental evidence of the involvement of thiosulfate reduction in microbial corrosion of steel. Strain SEBR 4207T cells were vibrios (3 to 5 by 1 pm), stained gram negative, and possessed lateral flagella. Spores were not detected. Optimum growth occurred in the presence of 3% NaCl at pH 7.0 and 42°C. Strain SEBR 4207T utilized peptides and amino acids, but not sugars or fatty acids. It fermented serine, histidine, and Casamino Acids, whereas arginine, glutamate, leucine, isoleucine, alanine, valine, methionine, and asparagine were only used in the presence of thiosulfate. Peptides were fermented to acetate, isobutyrate, isovalerate, 2-methylbutyrate, H,, and CO,. The addition of either thiosulfate or sulfur but not sulfate increased peptide utilization, growth rate, and biomass; during growth, H,S was produced and a concomitant decrease in H, was observed. The addition of either thiosulfate or sulfur also reversed H, inhibition. 16s rRNA sequence analysis indicates that strain SEBR 4207T is distantly related to members of the genus Thermoanuerobacter (83% similarity). Because the phenotypic and phylogenetic characteristics cannot be assigned to any described genus, strain SEBR 4207T is designated as a new species of a new genus, Dethiosulfovibrio peptidovorans gen. nov., sp. nov. Strain SEBR 4207T has been deposited in the Deutsche Sammlung von Mikroorganismen und zellkulturen GmbH (= DSM 11002).In 1989, Elf Congo experienced corrosion of the first 5 km of a 23-km main subsea pipeline that transported sour oil (i.e., H,S-containing petroleum) produced from the Emeraude oil field. The corroded segment was replaced, but it corroded again a year later. The whole line was then replaced and operated under a specifically designed biocide treatment regimen. The preliminary examination of the corroded iron showed that the breakthrough was due to bacterial pitting corrosion, with an unusually high penetration rate of about 1 cm per year. Chemical analysis of the pipeline water revealed the presence of up to 0.5 mM thiosulfate. It is likely that the thiosulfate was produced as a result of oxidation of the H,S naturally present in the oil field ecosystem by oxygen that is introduced in the pipelines during processing (10, 15, 22). The corrosion of pipelines was suspected to be due not only to sulfate but also to thiosulfate reduction by sulfate-reducing bacteria (SRB), because computer modeling had shown that thiosulfate reduction could induce the pitting corrosion of steel at higher rates than sulfate reduction (13).Since the pipeline was under a biocide treatment regimen during our microbiological investigations, the production fluids from several wellheads upstream of the line were collected and analyzed. Besides diffe...

thermophilic, glucose-fermenting, strictly anaerobic, rod-shaped bacterium, strain SEBR 6459T (T = type strain), was isolated from an African oil-producing well. This organism was identified as a member of the genus Thennotoga on the basis of the presence of the typical outer sheath-like structure (toga) and 16s rRNA signature sequences and its ability to grow on carbohydrates (glucose, arabinose, fructose, lactose, maltose, and xylose). Major differences in its 16s rRNA gene sequence, its lower optimum temperature for growth (66"C), its sodium chloride range for growth (0 to 2.8%), its lack of lactate as an end product from glucose fermentation, and its peritrichous flagella indicate that strain SEBR 6459T is not similar to the three previously described Thennotoga species. Furthermore, this organism does not belong to any of the other genera related to the order Thermotogales that have been described. On the basis of these findings, we propose that this strain should be described as a new species, Thermotoga ewi. The type strain of T. e@i is SEBR 6459 (= DSM 9442).The order Thermotogales currently comprises three genera, TheTotoga (17), Thermosipho (18), and Fervidobacterium (19, 35). All of the species belonging to these genera are rod shaped and have a characteristic outer sheath-like structure which can be observed under in situ conditions (34). Members of the recently described genera Geotoga and Petrotoga (9) also possess this morphological feature and, as determined by a 16s rRNA sequence analysis, are distantly related to members of the Thermotogales. Collectively, the five genera mentioned above represent one of the deepest phylogenetic branches in the domain Bacteria (42). These taxa can be differentiated on the basis of their optimum temperatures for growth; Thermotoga species are extreme thermophiles that have optimum temperatures for growth of around 80°C (17, 20, 21, 41), Thermosipho and Fervidobacterium species have optimum temperatures for growth of 65 to 75°C (18, 19, 35) and are regarded as thermophiles, and Geotoga and Petrotoga species are moderate thermophiles having optimum temperatures for growth of less than 60°C (9). Until recently, members of the three genera belonging to the order Therrnotogales (Therrnotoga, Therrnosipho, and Fervidobacterium) have been isolated only from volcanic aquatic environments. Different species have different sodium chloride requirements and optimum temperatures for growth. These differences reflect the restricted ecological habitats (hydrothermal marine environments, hydrothermal terrestrial environments) from which the organisms were isolated. However, Thermotoga species capable of growth at 85°C have recently been isolated from oil wells in the North Sea (39). Davey et al. (9) have also described the isolation of members of two new genera of moderate thermoanaerobes, the genera Petrotoga and Geotoga, from oil fields. These reports have extended our knowl- edge concerning the ecological habitats of these bacteria. In this paper, we describe the results...

Aims:  Grey mould caused by Botrytis cinerea is an economically important disease of strawberries in Tunisia and worldwide. The aim of this study was to select effective halophilic bacteria from hypersaline ecosystems and evaluate the abilities of antifungal bacteria to secrete extracellular hydrolytic enzymes, anti‐Botrytis metabolites and volatiles. Methods and Results:  Grey mould was reduced in strawberry fruits treated with halophilic antagonists and artificially inoculated with B. cinerea. Thirty strains (20·2%) were active against the pathogen and reduced the percentage of fruits infected after 3 days of storage at 20°C, from 50% to 91·66%. The antagonists were characterized by phenotypic tests and 16S rDNA sequencing. They were identified as belonging to one of the species: Virgibacillus marismortui, B. subtilis, B. pumilus, B. licheniformis, Terribacillus halophilus, Halomonas elongata, Planococcus rifietoensis, Staphylococcus equorum and Staphylococcus sp. The effective isolates were tested for antifungal secondary metabolites. Conclusions:  Moderately halophilic bacteria may be useful in biological control against this pathogen during postharvest storage of strawberries. Significance and Impact of the study:  The use of such bacteria may constitute an important alternative to synthetic fungicides. These moderate halophiles can be exploited in commercial production and application of the effective strains under storage and greenhouse conditions.

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Isolation and Characterization of Sporobacter sp. nov., from the Digestive Tract of the Termite Nasutitemes lujae ternitidis gen. nov., Wood-Feeding

Tomato is one of the leading crops in Tunisia in terms of weight consumed (20 kg⁄per person⁄year). Preserving the quality of the fruit from field to consumer is essential to successful marketing. Grey mould rot induced by Botrytis cinerea is an important cause of postharvest loss depending on season and handling practices. We describe here the ability of halotolerant to moderately halophilic bacteria isolated from different Tunisian Sebkhas (hypersaline soils) to protect freshmarket tomato fruits from B. cinerea. The tomatoes tested were at two different stages of ripening, (i) mature-green and (ii) red. Six strains significantly reduced growth of the pathogens from 67% to 87%. The effectiveness of these antagonists was also confirmed on green tomatoes; in which the fruit rot protection rate ranged from 74% to 100%. The antagonists were characterized by morphological, biochemical and physiological tests as well as 16S rDNA sequencing. The halotolerant effective isolates were identified as belonging to one of the species Bacillus subtilis (M1-20, J9) or B. licheniformis (J24). One effective moderately halophilic isolate (M2-26) was identified as Planococcus rifietoensis. These strains are a source of hydrolytic enzymes such as chitinases, proteases, laminarinases, amylases, lipases and cellulases. For comparison, 12 halotolerant or moderately halophilic strains obtained from DSM culture collection were also evaluated for their antifungal activity against B. cinerea on tomato fruits. The most effective strains were Halomonas subglaciescola, Halobacillus litoralis, Marinococcus halophilus, Salinococcus roseus, Halovibrio variabilis and Halobacillus halophilus with a percentage of grey mould rot reduction ranging from 71% to 97%. Inoculation of mature-green tomatoes by the bacterial antagonist of Halobacillus trueperi resulted in no disease development. Our results indicate that the use of halotolerant to halophilic microorganisms should be helpful in reducing grey mould disease of stored tomatoes.