Strain MB1 Research Articles

Early warning of Aspergillus contamination in maize by gas chromatography-ion mobility spectrometry.

As one of the main grain crops in China, maize is highly susceptible to Aspergillus infection during processing, storage and transportation due to high moisture at harvest, which results in the loss of quality. The aim of this study is to explore the early warning marker molecules when Aspergillus infects maize kernels. Firstly, strains MA and MB were isolated from moldy maize and identified by morphological characterization and 18S rRNA gene sequence analysis to be Aspergillus flavus (A. flavus) and Aspergillus niger (A. niger). Next, fresh maize was moldy by contaminated with strains MA and MB. The volatile organic compounds (VOCs) during the contamination process of two fungal strains were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS). A total of 31 VOCs were detected in maize contaminated with strain MA, a total of 32 VOCs were detected in maize contaminated with strain MB, including confirmed monomers and dimers. Finally, heat maps and principal component analysis (PCA) showed that VOCs produced in different growth stages of Aspergillus had great differences. Combined with the results of GC-IMS, total fungal colony counts and fungal spores, it was concluded that the Aspergillus-contaminated maize was in the early stage of mold at 18 h. Therefore, the characteristic VOCs butan-2-one, ethyl acetate-D, Benzaldehyde, and pentan-2-one produced by maize at 18 h of storage can be used as early mildew biomarkers of Aspergillus infection in maize. This study provided effective marker molecules for the development of an early warning and monitoring system for the degree of maize mildew in granaries.

Morchella Effectively Removes Microcystins Produced by Microcystis aeruginosa.

Microcystins (MCs) produced by Microcystis aeruginosa are harmful to animal and human health, and there is currently no effective method for their removal. Therefore, the development of biological approaches that inhibit cyanobacteria and remove MCs is needed. We identified strain MB1, confirmed as Morchella, using morphological and mole-cular evolution methods. To assess the impact of strain MB1 on M. aeruginosa, we conducted an experiment in which we inoculated M. aeruginosa with Morchella strain MB1. After their co-cultivation for 4‍ ‍d, the inoculation with 0.9696‍ ‍g MB1 completely inhibited and removed M. aeruginosa while concurrently removing up to 95% of the MC content. Moreover, within 3‍ ‍d of their co-cultivation, MB1 removed more than 50% of nitrogen and phosphorus from the M. aeruginosa solution. Therefore, the development of effective biological techniques for MC removal is paramount in safeguarding both the environment and human well-being. We herein successfully isolated MB1 from its natural habitat. This strain effectively inhibited and removed M. aeruginosa and also reduced the content of nitrogen and phosphorus in the M. aeruginosa solution. Most importantly, it exhibited a robust capability to eliminate MCs. The present results offer a new method and technical reference for mitigating harmful algal blooms.

Pigmented Microbial Extract (PMB) from Exiguobacterium Species MB2 Strain (PMB1) and Bacillus subtilis Strain MB1 (PMB2) Inhibited Breast Cancer Cells Growth In Vivo and In Vitro.

Breast cancer (BC) continues to be one of the major causes of cancer deaths in women. Progress has been made in targeting hormone and growth factor receptor-positive BCs with clinical efficacy and success. However, little progress has been made to develop a clinically viable treatment for the triple-negative BC cases (TNBCs). The current study aims to identify potent agents that can target TNBCs. Extracts from microbial sources have been reported to contain pharmacological agents that can selectively inhibit cancer cell growth. We have screened and identified pigmented microbial extracts (PMBs) that can inhibit BC cell proliferation by targeting legumain (LGMN). LGMN is an oncogenic protein expressed not only in malignant cells but also in tumor microenvironment cells, including tumor-associated macrophages. An LGMN inhibition assay was performed, and microbial extracts were evaluated for in vitro anticancer activity in BC cell lines, angiogenesis assay with chick chorioallantoic membrane (CAM), and tumor xenograft models in Swiss albino mice. We have identified that PMB from the Exiguobacterium (PMB1), inhibits BC growth more potently than PMB2, from the Bacillus subtilis strain. The analysis of PMB1 by GC-MS showed the presence of a variety of fatty acids and fatty-acid derivatives, small molecule phenolics, and aldehydes. PMB1 inhibited the activity of oncogenic legumain in BC cells and induced cell cycle arrest and apoptosis. PMB1 reduced the angiogenesis and inhibited BC cell migration. In mice, intraperitoneal administration of PMB1 retarded the growth of xenografted Ehrlich ascites mammary tumors and mitigated the proliferation of tumor cells in the peritoneal cavity in vivo. In summary, our findings demonstrate the high antitumor potential of PMB1.

Optimización de parámetros de cultivo de Pleurotus eryngii y desarrollo de cepas mejoradas por apareamiento de neohaplontes compatibles

Production parameters for cultivation of P. eryngii were established. With 21 days incubation, a substrate of wheat straw (45%), sawdust (20%), wheat bran (16%) and gluten (5%) packed in 3.5 kg bags produced higher BE (103%) than a cotton waste substrate (BE=74%). Cold treatment or scratching of substrate for induction of fruiting resulted unnecessary. Strains FQ and MB of P. eryngii were dedikaryotized by blending mycelium suspensions for 300 seconds and inoculation 50 µL of homogenate into solutions with 20 g/L glucose and peptone. In two dedikaryotization experiments, both component monokaryons (neohaplonts) were recovered from strains FQ and MB. Hybrids and reconstructed parental dikaryons were obtained by mating neohaplonts. The strains generated in the first dedikaryotization experiment were fruited. The parental strains produced lower BE (103, 84%) than reconstructed strains (183, 101%) and two hybrids (106, 174%). After a second dedikaryotization, 17 neohaplonts were mated to produce 3 reconstructed strains and 7 hybrids. Their growth curves were determined on 2 solid media (MEA agar and wheat). The Baranyi model showed the best adjustment to growth curves and allowed to separate them into statistically different groups and to calculate the corresponding kinetic parameters (μmax, λ) on MEA agar and wheat.

Evaluating Disease Threats to Sustainable Poultry Production in Africa: Newcastle Disease, Infectious Bursal Disease, and Avian Infectious Bronchitis in Commercial Poultry Flocks in Kano and Oyo States, Nigeria.

The growth of the poultry industry in Nigeria is constrained by major poultry diseases, despite the implementation of vaccination programs. This study aimed to assess the level of protection against Newcastle disease (ND), infectious bursal disease (IBD), and avian infectious bronchitis (IB) afforded by current vaccination schedules and characterize the circulating virus strains in commercial poultry flocks in Nigeria. A cross-sectional study was conducted on 44 commercial poultry farms in Oyo and Kano states of Nigeria. Serum and tissue samples and data on flock, clinical and vaccination records were collected on each farm. Farms were classified as being protected or not protected against ND, IBD and IB based on a defined criterion. Real-time reverse transcription polymerase chain reaction (rRT-PCR) testing was performed for each target virus on tissue samples and positive samples were sequenced. A total of 15/44 (34.1%), 35/44 (79.5%), and 1/44 (2.3%) farms were considered to be protected against ND, IBD, and IB, respectively, at the time of sampling. NDV RNA was detected on 7/44 (15.9%) farms and sequences obtained from 3/7 farms were characterized as the lentogenic strain. Infectious bursal disease virus (IBDV) RNA was detected on 16/44 (36.4%) farms tested; very virulent (vv) IBDV and non-virulent (nv) IBDV strains were both detected in 3/16 (18.8%) positive samples. Sequences of IBDV isolates were either clustered with a group of genotype 3 virulent IBDV strains or were related to vaccine strains MB and D78 strains. IBV RNA was detected on 36/44 (81.8%) farms, with variant02, Massachusetts, 4/91, and Q1 variants detected. Sequences of IBV isolates were either clustered with the vaccines strains Massachusetts M41 and H120 or were most closely related to the D274-like strains or a clade of sequences reported in Nigeria and Niger in 2006 and 2007. This study revealed that most study farms in Oyo and Kano states did not have adequate protective antibody titers against IBV and NDV and were therefore at risk of field challenge. Infectious bursal disease virus and IBV RNA were detected on farms with a history of vaccination suggesting potential vaccination failure, or that the vaccine strains used mismatch with the circulating strains and are therefore not protective.

A Host-Vector System for the Expression of a Thermostable Bacterial Lipase in a Locally Isolated Meyerozyma guilliermondii SMB.

Screening for a new yeast as an alternative host is expected to solve the limitations in the present yeast expression system. A yeast sample which was isolated from the traditional food starter ‘ragi’ from Malaysia was identified to contain Meyerozyma guilliermondii strain SMB. This yeast-like fungus strain SMB was characterized to assess its suitability as an expression host. Lipase activity was absent in this host (when assayed at 30 °C and 70 °C) and Hygromycin B (50 μg/mL) was found to be its best selection marker. Then, the hyg gene (Hygromycin B) was used to replace the sh ble gene (Zeocin) expression cassette in a Komagataella phaffii expression vector (designated as pFLDhα). A gene encoding the mature thermostable lipase from Bacillus sp. L2 was cloned into pFLDhα, followed by transformation into strain SMB. The optimal expression of L2 lipase was achieved using YPTM (Yeast Extract-Peptone-Tryptic-Methanol) medium after 48 h with 0.5% (v/v) methanol induction, which was 3 times faster than another K. phaffii expression system. In conclusion, a new host-vector system was established as a platform to express L2 lipase under the regulation of PFLD1. It could also be promising to express other recombinant proteins without inducers.

Characterization of a Linuron-Specific Amidohydrolase from the Newly Isolated Bacterium Sphingobium sp. Strain SMB.

The phenylurea herbicide linuron is globally used and has caused considerable concern because it leads to environmental pollution. In this study, a highly efficient linuron-transforming strain Sphingobium sp. SMB was isolated, and a gene (lahB) responsible for the hydrolysis of linuron to 3,4-dichloroaniline and N,O-dimethylhydroxylamine was cloned from the genome of strain SMB. The lahB gene encodes an amidohydrolase, which shares 20-53% identity with other biochemically characterized amidohydrolases, except for the newly reported linuron hydrolase Phh (75%). The optimal conditions for the hydrolysis of linuron by LahB were determined to be pH 7.0 and 30 °C, and the Km value of LahB for linuron was 37.3 ± 1.2 μM. Although LahB and Phh shared relatively high identity, LahB exhibited a narrow substrate spectrum (specific for linuron) compared to Phh (active for linuron, diuron, chlortoluron, etc.). Sequence analysis and site-directed mutagenesis revealed that Ala261 of Phh was the key amino acid residue affecting the substrate specificity. Our study provides a new amidohydrolase for the specific hydrolysis of linuron.

Mycoplasma bovis delay in apoptosis of macrophages is accompanied by increased expression of anti-apoptotic genes, reduced cytochrome C translocation and inhibition of DNA fragmentation

Bacterial pathogens have evolved to manipulate host cell death and survival pathways for their intracellular persistence. Understanding the ability of a bacterium to induce or inhibit cell death is essential for elucidating the disease pathogenesis and suggesting potential therapeutic options to manage the infection. In recent years, apoptosis inhibition by different bacteria has been suggested as a mechanism of survival by allowing the pathogen to replicate and disseminate in the host. Mycoplasma bovis has evolved mechanisms to invade and modulate apoptosis of bovine peripheral blood mononuclear cells (PBMC), red blood cells (RBCs), primary macrophages and monocytes. To date, these mechanisms are poorly understood. Using apoptosis assays such as Annexin V binding, caspases activity, reactive oxygen species production, DNA fragmentation and differential gene expression we set out to determine how M. bovis modulates macrophage survival. Using the BoMac cell line, we report a significant reduction in STS-induced apoptosis through caspase dependent manner. Besides activating the NF-kβ pathway and inhibiting caspases 3, 6 and 9, M. bovis strain Mb1 also inhibits production of reactive oxygen species and DNA fragmentation of the host cell. We also report a significant up-regulation of the anti-apoptotic genes Bcl-2 and Bcl-XL upon infection. Our results indicate that M. bovis strain Mb1 inhibits the intrinsic pathway of apoptosis and up-regulate survival genes in BoMac cells.

Microstructure, mechanical properties and biocorrosion behavior of dissimilar welds of AISI 904L and UNS S32750

This article addresses the joining of 5mm thick plates of marine grade, super-austenitic (AISI 904L) and super-duplex stainless steels (UNS S32750) by pulsed current gas tungsten arc welding using duplex and austenitic stainless steel fillers. Microstructure studies revealed the segregation of Mo-rich phases in the fusion zone while employing ERNiCrMo-10. Grain coarsening was observed at the heat affected zone (HAZ) of super-duplex stainless steel in both the cases. The study attested that all the tensile failures experienced in the parent metal, AISI 904L for both the weldments. Charpy V-notch impact studies demonstrated that the weldments employing ER2553 were experienced better impact toughness than ERNiCrMo-10 weldments. Further potentiodynamic polarization test in 3.5% NaCl environment was conducted on the coupons of the weldments. The coupons of the weldments were then tested for accelerated corrosion in salt fog chamber for 300h in 3.5% NaCl environment. This accelerated corrosion test concludes that the parent metal AISI 904L experienced better corrosion resistance than the fusion zones. The investigation also deals with biocorrosion studies of the dissimilar welds of super-austenitic and super-duplex stainless steels. Microbial consortium comprising of six bacterial isolates of which four were Pseudomonas strains P. aeruginosa strain MB1, P. aeruginosa strain MB2, P. fluorescens and P. flavescens, two belonged to Bacillus strains, B. subtilis and B. cereus, for the first time. The bacterial isolates were inoculated in the medium with the presence of the metal coupons. The results were obtained after 15 and 30days interval and compared with the control to determine the rate of biocorrosion which confirms that there is an accelerated deterioration of the metal coupons by the microbial strains.

Microbial Transformations of 6- and 7-Methoxyflavones in Aspergillus niger and Penicillium chermesinum Cultures

A detailed study of the biotransformation of 6- and 7-methoxyflavones by four fungal strains (Aspergillus niger strains MB, KB, and SBP; Penicillium chermesinum 113) was carried out. Products of demethylation and also demethylation combined with hydroxylation at C-4' were identified. The biotransformation products were stronger antioxidants than the substrates.

Pengaruh Pemberian Kulit Ari Biji Kedelai Hasil Fermentasi dengan Aspergillus niger sebagai Pengganti Jagung dan Bungkil Kedelai dalam Ransum terhadap Retensi Bahan Kering, Bahan Organik dan Serat Kasar pada Ayam Pedaging

The research on substitution of corn and soybean cake with fermented soybean husk by Aspergillus niger was done on 100 DOCs strains MB 202. Completely Randomizing Design (CRD) was used in five treatments: 0, 10, 20, 30 and 40% of fermented soybean husk by four replications. Observed variables were the retentions of dry matter, organic matter and crude fiber. Data were analyzed with analysis of variance continued by Duncan Multiple Range Test. The results showed that substitution of corn and soybeans cake with fermented soybean husk had no significant effect (P>0.05) on the retention of the dry matter but significantly (P<0.05) affected retentions of organic matter and crude fiber. In conclusion, the fermented soybeans husk can be used as a substitute for corn and soybean cake up to 40% of broiler feed.

Interactions between Two MerR Regulators and Three Operator/Promoter Regions in the Mercury Resistance Module ofBacillus megaterium

The mercury resistance module of Bacillus transposon TnMERI1 is regulated by three operator/promoter regions (O/P merB3, O/P merR1, and O/P merR2) and two regulatory proteins (MerR1 and MerR2) encoded by the module itself. To clarify the roles of MerR1 and MerR2 in the regulatory mechanism, both proteins were overexpressed and purified. MerR1 bound the regulatory regions O/P merB3 and O/P merR1, with a preference for O/P merB3 as measured on in vitro gel shift assays. However, MerR2 bound O/P merR2, as revealed by gel shift and restriction endonuclease protection assays. The transcriptional start sites of O/P merB3 and O/P merR2 were determined by rapid amplification of 5'-cDNA ends (5'-RACE) in the TnMERI1 original host, Bacillus megaterium strain MB1. Real-time reverse transcription polymerase chain reaction (RT-PCR) assays showed that O/P merB3 and O/P merR1 were induced in the presence of Hg2+ but not O/P merR2. It was concluded that MerR1 regulates O/P merB3 and O/P merR1, while MerR2 regulates O/P merR2.

Screening of isolated lactic acid bacteria as potential beneficial strains for fermented liquid pig feed production

In this paper the selection of potential probiotic strains for producing fermented liquid feed (FLF) for pigs is presented. One hundred and forty six strains of lactic acid bacteria were isolated from ileal digesta of piglets, cecal digesta of slaughter pigs and FLF from a preliminary trial at our laboratory. The strains were identified with repetitive-element PCR and partial 16S rRNA sequencing and screened for acidification potential. Ten of the strains were selected and their culture supernatant was checked for antibacterial activity against Salmonella spp. Also, they were tested in vitro in batch fermentations at 30 °C for 72 h, for their capacity to produce FLF (water:feed ratio of 4:1) with a concentration of acetic acid less than 40 mmol/L and of lactic acid above 100 mmol/L, resulting in a pH below 4.5. The Lactobacillus strains MB 3123 ( L. johnsonii), MB 3182 ( L. salivarius group) and MB 3083 ( L. plantarum) were found to be very effective for the production of FLF. The FLF produced by including this strain had a pH drop from 5.9 to 4.2, 4.3 and 4.4 after 24 h and to 4.1 after 48 h of fermentation. Also, these three strains showed high antimicrobial activity against Salmonella spp. and produced more than 100 mmol/L lactic acid after 48 h fermentation. The MB 3170 strain increased the lactic acid concentration above 100 mmol/L after 48 h, but at 24 h the pH was only 4.5. The results indicate that it is possible to screen for probiotic strains capable of fermenting feeds and of producing high quantities of lactic acid with possible antimicrobial effects in the gastro-intestinal tract of pigs.

Expressing a bacterial mercuric ion binding protein in plant for phytoremediation of heavy metals

A specific mercuric ion binding protein (MerP) originating from transposon Tn MERI1 of Bacillus megaterium strain MB1 isolated from Minamata Bay displayed good adsorption capability for a variety of heavy metals. In this study, the Gram-positive MerP protein was expressed in transgenic Arabidopsis to create a model system for phytoremediation of heavy metals. Under control of an actin promoter, the transgenic Arabidpsis showed higher tolerance and accumulation capacity for mercury, cadium and lead when compared with the control plant. Results from confocal microscopy analysis also indicate that MerP was localized at the cell membrane and vesicles of plant cells. The developed transgenic plants possessing excellent metal-accumulative ability could have potential applications in decontamination of heavy metals.

Facilities for transcription and mobilization of an exon-less bacterial group II intron nested in transposon Tn MERI1

Transcription and mobilization facilities of a group II intron, B.me.I1, which was classified within a group IIB subclass and nested in a broad-spectrum mercury resistance transposon Tn MERI1 found from the chromosome of Bacillus megaterium strain MB1 were investigated. Though B.me.I1 does not intervene in any recognizable exon gene, the splicing ability of B.me.I1 in Escherichia coli was confirmed by applying RT-PCR with RNA template transcribed by using a T7 RNA polymerase-promoter expression system. The homing activity of B.me.I1 was confirmed by using an intron-less allele fragment as a specific integration site which was cloned from Tn 5084, a Tn MERI1-family mercury resistance transposon. The transcription and splicing of B.me.I1 in the original host, the strain MB1, were also observed as its natural property. Primer-walking and 5′ RACE analyses showed that the transcription start site and the putative promoter region of B.me.I1 were located on the antisense strand of tnpR gene of Tn MERI1. Therefore, it is cleared that Tn MERI1 provides a specific integration site and facilities for transcription of B.me.I1. From these results, it is considered that these genetic facilities given by the transposon Tn MERI1 confer splicing and homing capability on B.me.I1, even though the group II intron is not associated with any exon gene.

Expression of mercuric reductase from Bacillus megaterium MB1 in eukaryotic microalga Chlorella sp. DT: an approach for mercury phytoremediation

A eukaryotic microalga, Chlorella sp. DT, was transformed with the Bacillus megaterium strain MB1 merA gene, encoding mercuric reductase (MerA), which mediates the reduction of Hg2+ to volatile elemental Hg0. The transformed Chlorella cells were selected first by hygromycin B and then by HgCl2. The existence of merA gene in the genomic DNA of transgenic strains was shown by polymerase chain reaction amplification, while the stable integration of merA into genomic DNA of transgenic strains was confirmed by Southern blot analysis. The ability to remove Hg2+ in merA transgenic strains was higher than that in the wild type. The merA transgenic strains showed higher growth rate and photosynthetic activity than the wild type did in the presence of a toxic concentration of Hg2+. Cultured with Hg2+, the expression level of superoxide dismutase in transgenic strains was lower than that in the wild type, suggesting that the transgenic strains faced a lower level of oxidative stress. All the results indicated that merA gene was successfully integrated into the genome of transgenic strains and functionally expressed to promote the removal of Hg2+.

J1 acylase, a glutaryl-7-aminocephalosporanic acid acylase from Bacillus laterosporus J1, is a member of the α/β-hydrolase fold superfamily

J1 acylase, a glutaryl-7-aminocephalosporanic acid acylase (GCA) isolated from Bacillus laterosporus J1, has been conventionally grouped as the only member of class V GCA, although its amino acid sequence shares less than 10% identity with members of other classes of GCA. Instead, it shows higher sequence similarities with Rhodococcus sp. strain MB1 cocaine esterase ( RhCocE) and Acetobacter turbidans α-amino acid ester hydrolase ( AtAEH), members of the α/β-hydrolase fold superfamily. Homology modeling and secondary structure prediction indicate that the N-terminal region of J1 acylase has an α/β-hydrolase folding pattern. The catalytic triads in RhCocE and AtAEH were identified in J1 acylase as S125, D264 and H309. Mutations to alanine at these positions were found to completely inactivate the enzyme. These results suggest that J1 acylase is a member of the α/β-hydrolase fold superfamily with a serine–histidine–aspartate catalytic triad.

Bioluminescence Biosensor for the Detection of Organomercury Contamination

AbstractTo selectively detect organomercurial compounds in the environment, in this study a bioluminescence biosensor for organomercurials was developed using a bacterial gene expression system for the mercury resistance determinant. merB3‐Luciferase (mer‐lux) transcriptional fusion plasmids pHYΔ3Lux and pHY.Δ3Lux were constructed to evaluate the gene expression system with a new organomercury lyase gene merB3 from Bacillus megaterium strain MB1, which is resistant to a broad spectrum of mercury compounds, and with its 3'end‐deleted defective merB3, respectively. Another plasmid, pGR1A, encoding an operator/promoter sequence, merR1, merE, merT, merP and merA from the same bacterial strain was constructed and used as a transacting gene expression vector which combines the gene expression vector of mer‐lux transcriptional fusion plasmids in the same Escherichia coli cells. The transformants that carried a set of the two plasmids were used as biological sensors for the detection of organomercurials. Transformant (E. coli DH5α/pHYB3Lux, pGR1A) is available to distinguish the organomercury from inorganic mercury, since inorganic mercurials can induce the bioluminescence of both the bacterial strain lines with pHYΔB3Lux and pHYB3Lux, whereas organomercurials can only induce the bioluminescence of the lines with pHYB3Lux. These experimental results showed that the transformant with a merB3‐defective fusion plasmid, and the gene expression vector responded to only mercury chloride. On the other hand, the transformant with an intact merB3 fusion plasmid and the gene expression vector responded to mercury chloride and all organomercurials tested in the study. The sensor system responded to the existence of the phenyl mercury acetate of 50 nanomolar and was more sensitive than that of inorganic mercury (100 nanomolar). The result also indicated the capability of the system to detect bio‐affecting inorganic mercury from several hundred nanomolar to several ten micromolar.

Characterization of two regulatory genes of the mercury resistance determinants from TnMERI1 by luciferase-based examination

The broad-spectrum mercury resistance transposon, TnMERI1, of Bacillusmegaterium strain MB1, contains three proposed operator/promoter (O/P) transcriptional start sites and two regulatory genes (merR1 and merR2). A series of luciferase (lux)-based transcriptional fusion plasmids were studied in Escherichiacoli to show that both merR1 and merR2 gene products repressed transcription from O/PmerB3, O/PmerR1, and O/PmerR2 under uninduced conditions. Derepression occurred when the merR1 gene was present and Hg2+ functioned as an inducer. In the presence of organomercurial compounds, basal transcription of merB3 was needed to produce inorganic Hg2+ as the inducer of expression regulated by MerR1 at O/PmerB3. The presence of merR2 repressed transcription from all three O/Pmer sites under both non-induced conditions and when inorganic Hg2+ or organomercurials were added. These results show that MerR1 functions as a repressor in the absence of Hg2+ and as an activator in the presence of Hg2+, while MerR2 functions as a repressor.

Reclassification of the only species of the genus Desulfomonas, Desulfomonas pigra, as Desulfovibrio piger comb. nov.

The growth characteristics, DNA G+C content and sequences of 16S rDNA and the transcribed 16S-23S rDNA internal spacer were determined for Desulfomonas pigra ATCC 29098T, Desulfovibrio desulfuricans subsp. desulfuricans strains Essex 6T (= ATCC 29577T) and MB (= ATCC 27774) and 'Desulfovibrio fairfieldensis' ATCC 700045. Despite phenotypic differences (shape and motility) between Desulfomonas pigra and Desulfovibrio strains, the molecular analysis suggests that Desulfomonas pigra should be reclassified within the genus Desulfovibrio. Thus, the reclassification is proposed of Desulfomonas pigra, the type and only species of the genus, as Desulfovibrio piger comb. nov., which implies the emendation of the description of the genus Desulfovibrio.