Frigoriglobus tundricola gen. nov., sp. nov., a psychrotolerant cellulolytic planctomycete of the family Gemmataceae from a littoral tundra wetland.

Planctomycetes of the family Gemmataceae are characterized by large genome sizes and cosmopolitan distribution in freshwater and terrestrial environments but their ecological functions remain poorly understood. In this study, we characterized a novel representative of this family, strain PL17T, which was isolated from a littoral tundra wetland and was capable of growth on xylan and cellulose. Cells of this isolate were represented by pink-pigmented spheres that multiplied by budding and occurred singly or in short chains and aggregates. Strain PL17T was obligately aerobic, mildly acidophilic chemoorganotrophic bacterium, which displayed good tolerance of low temperatures. The major fatty acids were C18:0, C16:1ω5, and ßOH-C16:1; the major polar lipid was trimethylornithine. The genome of strain PL17T consisted of a 9.83 Mb chromosome and a 24.69kb plasmid. The G+C contents of the chromosomal and plasmid DNA were 67.4 and 62.3mol%, respectively. Over 8900 potential protein-coding genes were identified in the genome including a putative cellulase that contains a domain from the GH5 family of glycoside hydrolases. The genome of strain PL17T contained one linked and one unlinked rRNA operons with 16S rRNA gene sequences displaying 94.5% similarity to that in Gemmata obscuriglobus UQM2246T. Based on the results of comparative phenotypic, chemotaxonomic and phylogenomic analyses, we propose to classify strain PL17T (= CECT 9407T=VKM B-3467T) as representing a novel genus and species of the family Gemmataceae, Frigoriglobus tundricola gen. nov., sp. nov.

Norfloxacin salts of carboxylic acids curtail planktonic and biofilm mode of growth in ESKAPE pathogens.

AIMS: To enhance the antimicrobial and antibiofilm activity of norfloxacin against the planktonic and biofilm mode of growth in ESKAPE pathogens using chemically modified norfloxacin salts. METHODS AND RESULTS: Antimicrobial testing, synergy testing and time-kill curve analysis were performed to evaluate antibacterial effect of norfloxacin carboxylic acid salts against ESKAPE pathogens. In vivo efficacy to reduce bacterial bioburden was evaluated in zebrafish infection model. Crystal violet assay and live-dead staining were performed to discern antibiofilm effect. Membrane permeability, integrity and molecular docking studies were carried out to ascertain the mechanism of action. The carboxylic acid salts, relative to parent molecule norfloxacin, displayed two- to fourfold reduction in minimum inhibitory concentration against Staphylococcus aureus and Pseudomonas aeruginosa, in addition to displaying potent bacteriostatic effect against certain members of ESKAPE pathogens. In vivo treatments revealed that norfloxacin tartrate (SRIN2) reduced MRSA bioburden by greater than 1 log fold relative to parent molecule in the muscle tissue. In silico docking with gyrA of S. aureus showed increased affinity of SRIN2 towards DNA gyrase. The enhanced antibacterial effect of norfloxacin salts could be partially accounted by altered membrane permeability in S. aureus and perturbed membrane integrity in P. aeruginosa. Antibiofilm studies revealed that SRIN2 (norfloxacin tartrate) and SRIN3 (norfloxacin benzoate) exerted potent antibiofilm effect particularly against Gram-negative ESKAPE pathogens. The impaired colonization of both S. aureus and P. aeruginosa due to improved norfloxacin salts was further supported by live-dead imaging. CONCLUSION: Norfloxacin carboxylic acid salts can act as potential alternatives in terms of drug resensitization and reuse. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study shows that carboxylic acid salts of norfloxacin could be effectively employed to treat both planktonic- and biofilm-based infections caused by select members of ESKAPE pathogens.

The role of mass spectrometry analysis in bacterial effector characterization.

Many secreted bacterial effector proteins play a critical role in host-pathogen interactions by mediating a variety of post-translational modifications, some of which do not occur natively within the eukaryotic proteome. The characterization of bacterial effector protein activity remains an important step to understanding the subversion of host cell biology during pathogen infection and although molecular biology and immunochemistry remain critical tools for gaining insights into bacterial effector functions, increasingly mass spectrometry (MS) and proteomic approaches are also playing an indispensable role. The focus of this editorial is to highlight the strengths of specific MS approaches and their utility for the characterization of bacterial effector activity. With the capability of new generation MS instrumentation, MS-based technologies can provide information that is inaccessible using traditional molecular or immunochemical approaches.

Bacterial biofilm diversity in contact lens-related disease: emerging role of Achromobacter, Stenotrophomonas, and Delftia.

PURPOSE: Multi-species biofilms associated with contact lens cases and lenses can predispose individuals to contact lens-related inflammatory complications. Our study used culture-independent methods to assess the relationship between the severity of contact lens-related disease and bacteria residing in biofilms of contact lens cases and lenses. METHODS: Contact lens cases and lenses from 28 patients referred to the West Virginia University Eye Institute and diagnosed as having mild keratitis, keratitis with focal infiltrates, or corneal ulcers were processed and evaluated for bacterial composition based on 16S ribosomal RNA gene sequencing. Cases and lenses from nine asymptomatic contact lens wearers were processed in a manner similar to controls. Relationships between disease severity, bacterial types, and bacterial diversity were evaluated statistically. RESULTS: Disease severity and presenting visual acuity correlated with an increase in the diversity of bacterial types isolated from contact lens cases. A significant difference also was observed in the number of bacterial types associated with the three clinical groups. Achromobacter, Stenotrophomonas, and Delftia were prevalent in all disease groups, and Achromobacter and Stenotrophomonas were present in one asymptomatic control. Scanning electron microscopy revealed that Achromobacter and Stenotrophomonas formed a biofilm on the surface of contact lenses. CONCLUSIONS: Culture-independent methods identified an association between disease severity and bacterial diversity in biofilms isolated from cases and lenses of patients with contact lens-related corneal disease. Achromobacter, Stenotrophomonas, and Delftia were predominant bacteria identified in our study, drawing attention to their emerging role in contact lens-related disease.

Optimization of hot water treatment for removing microbial colonies on fresh blueberry surface.

UNLABELLED: Blueberries for the frozen market are washed but this process sometimes is not effective or further contaminates the berries. This study was designed to optimize conditions for hot water treatment (temperature, time, and antimicrobial concentration) to remove biofilm and decrease microbial load on blueberries. Scanning electron microscopy (SEM) image showed a well-developed microbial biofilm on blueberries dipped in room temperature water. The biofilm consisted of yeast and bacterial cells attached to the berry surface in the form of microcolonies, which produced exopolymer substances between or upon the cells. Berry exposure to 75 and 90 °C showed little to no microorganisms on the blueberry surface; however, the sensory quality (wax/bloom) of berries at those temperatures was unacceptable. Response surface plots showed that increasing temperature was a significant factor on reduction of aerobic plate counts (APCs) and yeast/mold counts (YMCs) while adding Boxyl® did not have significant effect on APC. Overlaid contour plots showed that treatments of 65 to 70 °C for 10 to 15 s showed maximum reductions of 1.5 and 2.0 log CFU/g on APCs and YMCs, respectively; with acceptable level of bloom/wax score on fresh blueberries. This study showed that SEM, response surface, and overlaid contour plots proved successful in arriving at optima to reduce microbial counts while maintaining bloom/wax on the surface of the blueberries. PRACTICAL APPLICATION: Since chemical sanitizing treatments such as chlorine showed ineffectiveness to reduce microorganisms loaded on berry surface (Beuchat and others 2001, Sapers 2001), hot water treatment on fresh blueberries could maximize microbial reduction with acceptable quality of fresh blueberries.

Impacto da doença periodontal na diabetes mellitus e em suas complicações

A diabetes mellitus e a doença periodontal são doenças inflamatórias crônicas que têm um grande impacto na saúde e no bem estar sistêmico. A doença periodontal é uma doença inflamatória crônica induzida por bactérias Gram-negativas e anaeróbicas...

Phage specificity and lipopolysaccarides of stem- and root-nodulating bacteria (Azorhizobium caulinodans, Sinorhizobium spp., and Rhizobium spp.) of Sesbania spp.

Phage susceptibility pattern and its correlation with lipopolysaccharide (LPS) and plasmid profiles may help in understanding the phenotypic and genotypic diversity among highly promiscuous group of rhizobia nodulating Sesbania spp.; 43 phages were from two stem-nodulating bacteria of S. rostrata and 16 phages were from root-nodulating bacteria of S. sesban, S. aegyptica and S. rostrata. Phage susceptibility pattern of 38 Sesbania nodulating bacteria was correlated with their LPS rather than plasmid profiles. Different species of bacteria (A. caulinodans- ORS571, SRS1-3 and Sinorhizobium saheli- SRR907, SRR912) showing distinct LPS subtypes were susceptible to different group of phages. Phages could also discriminate the strains of Si. saheli (SSR312, SAR610) possessing distinct LPS subtypes. Phages of Si. meliloti (SSR302) were strain-specific. All the strains of R. huautlense having incomplete LPS (insignificant O-chain) were phage-resistant. In in vitro assay, 100% of the phages were adsorbed to LPS of indicator bacterium or its closely related strain(s) only. These observations suggest the significance of LPS in phage specificity of Sesbania nodulating rhizobia. Highly specific phages may serve as biological marker for monitoring the susceptible bacterial strains in culture collections and environment.

[Vitamin B12-independent strains of Methylophaga marina isolated from Red Sea algae].

Two strains (KM3 and KM5) of halophilic methylobacteria isolated from Red Sea algae do not require vitamin B12 for growth and can use methanol, methylamine, dimethylamine, trimethylamine, dimethyl sulfide, and fructose as sources of carbon and energy. The cells of these strains are gram-negative motile monotrichous (strain KM3) or peritrichous (strain KM5) rods. The strains are strictly aerobic and require Na+ ions but not growth factors for growth. They are oxidase- and catalase-positive and reduce nitrates to nitrites. Both strains can grow in a temperature range of 4 to 37 degrees C (with optimal growth at 29-34 degrees C), at pH between 5.5 and 8.5 (with optimal growth at pH 7.5-8.0), and in a range of salt concentrations between 0.5 and 15% NaCl (with optimal growth at 5-9% NaCl). The phospholipids of these strains are dominated by phosphatidylethanolamine and phosphatidylglycerol and also include phosphatidylcholine, phosphatidylserine, and cardiolipin. The dominant fatty acids are C(16:1omega7c) and C(16:0). The major ubiquinone is Q8. The cells accumulate ectoin, glutamate, and sucrose as intracellular osmoprotectants. The strains implement the 2-keto-3-deoxy-6-phosphogluconate-dependent variant of the ribulose monophosphate pathway. The G+C content of the DNA is 44.4-44.7 mol %. Analysis of the 16S rRNA genes showed that both strains belong to Gammaproteobacteria and have a high degree of homology (99.4%) to Methylophaga marina ATCC 35842T . Based on the data of polyphasic taxonomy, strains KM3 and KM5 are identified as new strains M. marina KM3 (VKM B-2386) and M. marina KM5 (VKM B-2387). The ability of these strains to produce auxins (indole-3-acetic acid) suggests their metabolic association with marine algae.

Sporulating bacteria prefers predation to cannibalism in mixed cultures.

Predatory behavior, a property associated with ecosystems, is not commonly observed in microorganisms. However, cannibalistic tendencies have been observed in microorganisms under stress. For example, pure culture of Bacillus subtilis exhibits cannibalism under nutrient limitation. It has been proposed that a fraction of cells in the population produce Spo0A, a regulatory protein that is responsible for delaying sporulation. Cells containing spo0A would produce a killing factor by activating skf operon and an associated pump to export the factor. Cells that do not contain spo0A in the population are lysed. However in addition to the competition among the cells of B. subtilis, these cells also compete with other organisms for the limited nutrients. In this work, we report the cannibalistic behavior of B. subtilis in presence of Escherichia coli under severe nutritional limitation. We demonstrate that B. subtilis lyses cells of E. coli using an antibacterial factor under the regulation of Spo0A. Our experiments also suggest that B. subtilis prefers predation of E. coli to cannibalism in mixed cultures. B. subtilis also demonstrated predation in mixed cultures with other soil microorganisms, such as, Xanthomonas campestris, Pseudomonas aeruginosa and Acinetobactor lwoffi. This may offer B. subtilis a niche to survive in an environment with limited nutrients and under competition from other microorganisms.

Isolation of soil bacteria adapted to degrade humic acid-sorbed phenanthrene.

The goal of these studies was to determine how sorption by humic acids affected the bioavailability of polynuclear aromatic hydrocarbons (PAHs) to PAH-degrading microbes. Micellar solutions of humic acid were used as sorbents, and phenanthrene was used as a model PAH. Enrichments from PAH-contaminated soils established with nonsorbed phenanthrene yielded a total of 25 different isolates representing a diversity of bacterial phylotypes. In contrast, only three strains of Burkholderia spp. and one strain each of Delftia sp. and Sphingomonas sp. were isolated from enrichments with humic acid-sorbed phenanthrene (HASP). Using [14C]phenanthrene as a radiotracer, we verified that only HASP isolates were capable of mineralizing HASP, a phenotype hence termed "competence." Competence was an all-or-nothing phenotype: noncompetent strains showed no detectable phenanthrene mineralization in HASP cultures, but levels of phenanthrene mineralization effected by competent strains in HASP and NSP cultures were not significantly different. Levels and rates of phenanthrene mineralization exceeded those predicted to be supported solely by the metabolism of phenanthrene in the aqueous phase of HASP cultures. Thus, competent strains were able to directly access phenanthrene sorbed by the humic acids and did not rely on desorption for substrate uptake. To the best of our knowledge, this is the first report of (i) a selective interaction between aerobic bacteria and humic acid molecules and (ii) differential bioavailability to bacteria of PAHs sorbed to a natural biogeopolymer.

Influence of growth environment on coaggregation between freshwater biofilm bacteria.

AIM: To characterize the expression of coaggregation between Blastomonas natatoria 2.1 and Micrococcus luteus 2.13 following growth in liquid culture, on agar and in an artificial biofilm matrix composed of poloxamer hydrogel. METHODS AND RESULTS: The ability of B. natatoria 2.1 and M. luteus 2.13 to coaggregate with one another was assessed following growth in liquid culture as colonies on agar or within a poloxamer hydrogel matrix. In all these environments a cycle of gain and loss of coaggregation occurred when the two cell types were aged simultaneously, with optimum expression occurring in early stationary phase. Blastomonas natatoria 2.1 cells only coaggregated maximally after entry into stationary phase. Conversely, M. luteus 2.13 cells only coaggregated in exponential phase and early stationary phase and coaggregation ability was lost in late stationary phase. Maximal coaggregation therefore only occurred between the two strains if both were in early stationary phase, when the surface properties of the two cell types were optimal for coaggregation. CONCLUSION: In addition to occurring between cells grown in liquid culture, coaggregation between aquatic bacteria occurs after growth as a biofilm on agar and in an artificial biofilm matrix in poloxamer. Under all conditions, the B. natatoria 2.1 coaggregation adhesin and complementary receptor on M. luteus 2.13 were only expressed simultaneously during early stationary phase.

Modeling of chlorine effect on floc forming and filamentous micro-organisms of activated sludges.

Chlorination is the most economical, non-specific method to control the excessive growth of filamentous micro-organisms causing bulking in activated sludge systems in the treatment of food industrial wastewaters; it was one of the first methods used to control filamentous bulking and is still widely employed. Considering that chlorination affects both floc-forming and filamentous micro-organisms and leaves undesirable disinfection by-products, it is necessary to define the adequate doses to control bulking, minimizing the effect on floc-forming bacteria. In the present work the effect of biomass concentration and type of micro-organism on chlorine decay kinetics was evaluated; the inactivation of either a filamentous (Sphaerotilus natans) or a floc-forming (Acinetobacter anitratus) micro-organism due to chlorination was also analyzed. For chlorine decay assays, the samples were treated in a batch system with sodium hypochlorite ranging between 9.8 and 56.6 mg Cl(2) (gVSS)(-1). Respirometric assays were used to evaluate the effect of chlorine on micro-organisms respiratory activity; in these cases, sodium hypochlorite doses ranged between 2.5 and 18 mgCl(2) (gVSS)(-1).A model that allowed to predict simultaneously chlorine consumption and respiratory activity decay for both micro-organisms as a function of time was proposed. The model includes three coupled differential equations corresponding to respiratory inhibition, readily organic matter oxidation by chlorine and chlorine decay. The rate of chlorine decay depended on both, type and concentration of the micro-organisms in the system. Chlorine consumption rate due to S. natans was 2-4 times faster than A. anitratus. Using the proposed model initial critical chlorine doses (the lowest initial dose that leads to a total inhibition of the respiratory activity) were calculated for both micro-organisms and values of 11.9 mgCl(2) (gVSS)(-1) for S. natans and 4.5 mgCl(2) (gVSS)(-1) for A. anitratus were obtained. These critical doses indicated that in non flocculated pure cultures, floc-former bacteria A. anitratus was more susceptible to chlorine action than S. natans.

Gelidibacter mesophilus sp. nov., a novel marine bacterium in the family Flavobacteriaceae.

Two Gram-negative, aerobic, heterotrophic, marine bacteria, isolated from Mediterranean sea water off the coast near Valencia (Spain), were the object of this study. These non-motile, yellow-pigmented, rod-shaped strains have been studied by means of DNA-DNA hybridization, 16S rRNA sequencing and cultural and physiological features. Phylogenetic analysis showed that both strains belong to the phylum Cytophaga-Flavobacterium-Bacteroides, and their closest neighbour is the psychrophilic bacterium Gelidibacter algens. The two strains differ from G. algens in their mesophilic behaviour, hydrolytic pattern and use of different carbon sources. There is 31% DNA-DNA hybridization between the proposed type strain and G. algens, and both isolates show 97.5% 16S rDNA similarity to G. algens. They represent a novel species of the genus Gelidibacter, for which the name Gelidibacter mesophilus sp. nov. is proposed, with strain 2SM29T (= CECT 5103T = DSM 14095T) as the type strain.

A patient with severe acute pancreatitis successfully treated with a new critical care procedure.

It has been accepted widely that excessive humoral mediators play important roles in the pathogenesis of organ failure in patients with severe acute pancreatitis (SAP) and that infection of the pancreas due to bacterial translocation (BT) is the most frequent cause of death in SAP. On the other hand, it has been reported that continuous hemodiafiltration (CHDF) removes humoral mediators on hypercytokinemic patients such as those with systemic inflammatory response syndrome. Furthermore, several clinical studies have demonstrated that selective digestive decontamination (SDD) effectively eliminates aerobic Gram-negative bacteria from the intestinal tract and reduces the incidence of septic complications in SAP. Herein we report a case of SAP who was treated successfully with intensive care including CHDF and SDD. Thus, this case report suggests that CHDF aimed at removing causative humoral mediators and SDD for the prevention of BT are useful new tools for the management of SAP.

Probiotic supplementation reduces the risk of bacterial translocation in experimental short bowel syndrome.

BACKGROUND/PURPOSE: Probiotics are live organisms that survive passage through the gastrointestinal tract and have beneficial effects on the host. Lactobacillus and Bifidobacterium have been recommended for cholesterol lowering, acute diarrhea, prevention of cancer, or inflammatory bowel disease. On the other hand, after massive bowel resection, bacterial overgrowth is frequent and favors bacterial translocation (BT). The possible beneficial effects of Bifidobacterium lactis (BL) administration on BT in experimental short bowel syndrome (SBS), have not been investigated. The aim of this study was to test the hypothesis that BL administration decreases BT in SBS in animals fed orally. METHODS: One hundred twenty-eight adult Wistar rats fed orally with standard rat chow and tap water "ad libitum" were maintained in individual metabolic cages for 10 days and divided into 3 groups: control group (n = 71): nonmanipulated animals; RES group (n = 39): 80% gut resection from 10 cm beyond the angle of Treitz to 10 cm above the cecum; RES-PRO group (n = 18): same resection and daily 7.8 x 10(8) CFU B Lactis administration, after orogastric intubation. At the end of the experiment they were killed, and mesenteric lymph nodes (MLN) and peripheral and portal blood specimens were recovered and cultured. Bacterial identification in blood was made by conventional methods, and MLN culture was considered positive with a growth over 100 CFU/g. RESULTS: Bacterial translocation was detected in 6% of control group rats. The incidence of BT in the RES group was 87% (34 of 39), whereas only 50% (9 of 18) of RES-PRO animals had BT (P <.05). The relative risk reduction (RRR) was 0.43 (95% Cl 0.14 to 0.72), and the number needed to treat (NNT) was 3 (95% Cl 2 to 8). In other words, animals that received BL had the risk of BT reduced by 43% (RRR of 0.43), and of every 3 animals treated, 1 is expected to be free of BT (NNT of 3). CONCLUSION: Administration of B Lactis reduces the incidence of BT in adult Wistar rats after 80% gut resection.

Effect of oxide formation mechanisms on lead adsorption by biogenic manganese (hydr)oxides, iron (hydr)oxides, and their mixtures.

The effects of iron and manganese (hydr)oxide formation processes on the trace metal adsorption properties of these metal (hydr)oxides and their mixtures was investigated by measuring lead adsorption by iron and manganese (hydr)oxides prepared by a variety of methods. Amorphous iron (hydr)oxide formed by fast precipitation at pH 7.5 exhibited greater Pb adsorption (gamma(max) = 50 mmol of Pb/mol of Fe at pH 6.0) than iron (hydr)oxide formed by slow, diffusion-controlled oxidation of Fe(II) at pH 4.5-7.0 or goethite. Biogenic manganese(III/IV) (hydr)oxide prepared by enzymatic oxidation of Mn(II) by the bacterium Leptothrix discophora SS-1 adsorbed five times more Pb (per mole of Mn) than an abiotic manganese (hydr)oxide prepared by oxidation of Mn(II) with permanganate, and 500-5000 times more Pb than pyrolusite oxides (betaMnO2). X-ray crystallography indicated that biogenic manganese (hydr)oxide and iron (hydr)oxide were predominantly amorphous or poorly crystalline and their X-ray diffraction patterns were not significantly affected by the presence of the other (hydr)oxide during formation. When iron and manganese (hydr)oxides were mixed after formation, or for Mn biologically oxidized with iron(III) (hydr)oxide present, observed Pb adsorption was similar to that expected for the mixture based on Langmuir parameters for the individual (hydr)oxides. These results indicate that interactions in iron/manganese (hydr)oxide mixtures related to the formation process and sequence of formation such as site masking, alterations in specific surface area, or changes in crystalline structure either did not occur or had a negligible effect on Pb adsorption by the mixtures.

Thermobacillus xylanilyticus gen. nov., sp. nov., a new aerobic thermophilic xylan-degrading bacterium isolated from farm soil.

An aerobic, thermophilic, xylanolytic, spore-forming bacterium, XETP (T = type strain; P = patent strain), has been isolated from farm soil situated underneath a manure heap in northern France. Strain XETP, which stained negative in the Gram test, occurs as short rods which sometimes form chains. Its spores are ellipsoidal, central to subterminal and occur in swollen sporangia. It grows at temperatures up to 63 degrees C and in the pH range 6.5-8.5. When grown on glucose in optimal conditions, its doubling time was found to be 33 min. CO2 was observed to have a growth-stimulating effect at the start of the culture. In addition to glucose, the isolate utilizes xylose, arabinose, mannose, cellobiose, galactose, maltose, sucrose, xylan and starch. Growth is inhibited by 5% NaCl. The G+C content of strain XETP is 57.5 mol%. The 16S rDNA sequence analysis indicated that strain XETP falls into the radiation of the Bacillus-Lactobacillus-Streptococcus subdivision of the Gram-positive phylum. Its three closest phylogenetic relatives are 'Bacillus viscosus', Paenibacillus curdlanolyticus and Bacillus popilliae with identity values of 91.15, 90.94 and 90.92%, respectively. The major cellular fatty acids are 14-methyl pentadecanoic acid (16:0 iso), hexadecanoic acid (16:0) and 14-methyl hexadecanoic acid (17:0 anteiso). On the basis of 16S rRNA sequence and chemotaxonomic characteristics, the isolate is different enough for it to be considered as a member of a new genus. It is therefore proposed that this isolate represents a new genus and species: Thermobacillus xylanilyticus. Strain XETP, the type strain of Thermobacillus xylanilyticus, has been deposited in the Collection Nationale de Cultures Microbiennes (CNCM I-1017) as a patent strain.

Leptospirillum gen. nov. (ex Markosyan 1972), nom. rev., including Leptospirillum ferrooxidans sp. nov. (ex Markosyan 1972), nom. rev. and Leptospirillum thermoferrooxidans sp. nov. (Golovacheva et al. 1992).

The name Leptospirillum ferrooxidans is not in the Approved Lists of Bacterial Names (1980), nor has it been subsequently validly published. In accordance with the rules of the International Code of Nomenclature of Bacteria, the name Leptospirillum for the genus (gen. nov., nom. rev.) and Leptospirillum ferrooxidans for the species (sp. nov., nom. rev.) is revived here. The type species is Leptospirillum ferrooxidans strain L15T (= DSM 2705T). The second species in the genus is Leptospirillum thermoferrooxidans (Golovacheva et al. 1992) (type strain L-88T; Institute of Microbiology, INMI, Moscow, Russia).

Pseudoalteromonas peptidolytica sp. nov., a novel marine mussel-thread-degrading bacterium isolated from the Sea of Japan.

A new bacterial species belonging to the genus Pseudoalteromonas is described on the basis of phenotypic characterization, and sequence analysis of its 16S rRNA-coding and gyrase B (gyrB) genes. Ten strains, isolated from sea water of Yamato Island, Sea of Japan, were Gram-negative, yellow, motile, polarly flagellated, aerobic, rod-shaped eubacteria and had a G + C content of 42 mol%. Analysis of the 16S rDNA sequence revealed a clear affiliation between these strains and members of the gamma-Proteobacteria. High similarity values were found with members of the genus Pseudoalteromonas and this was supported by fatty acid profiles. The 16S rDNA sequence similarity between strain F12-50-A1T and Pseudoalteromonas piscicida was very high (99.1%). However, molecular characterizations employing small subunit 16S rDNA sequences were at the limits of resolution for the differentiation of species in this genus. As a result, DNA-DNA hybridization and sequence analyses of a more rapidly evolving gyrB gene were performed. Our assertion that this strain represents a distinct bacterial species within the genus Pseudoalteromonas was supported by both of these molecular analyses. Species-specific PCR probes were designed for the gyrB gene and used for the rapid screening of F12-50-A1T-like strains, thereby confirming the species. As these strains cleave complex protein compounds of the Mytilus edulis foot by secreting proteases, the name Pseudoalteromonas peptidolytica sp. nov. is proposed, with strain F12-50-A1T (= MBICC F1250A1T) as the type strain.

Phylogenetic characterization of a novel radiation-resistant bacterium from irradiated pork: description of Hymenobacter actinosclerus sp. nov.

A phylogenetic analysis was performed on a red-pigmented, radiation-resistant, Gram-negative, rod-shaped organism originating from irradiated pork. Comparative 16S rRNA gene sequencing showed the bacterium was a member of the Cytophaga-Flavobacterium-Bacteroides line of descent and represents a new subline within the genus Hymenobacter. A new species, Hymenobacter actinosclerus, is described for this novel radiation-resistant bacterium. The type strain of Hymenobacter actinosclerus is CCUG 39621T.