A Novel Cholinergic Action of Alcohol and the Development of Tolerance to That Effect in Caenorhabditis elegans

The Prp43 DExD/H-box protein is required for progression of the biochemically distinct pre-messenger RNA and ribosomal RNA (rRNA) maturation pathways. In Saccharomyces cerevisiae, the Spp382/Ntr1, Sqs1/Pfa1, and Pxr1/Gno1 proteins are implicated as cofactors necessary for Prp43 helicase activation during spliceosome dissociation (Spp382) and rRNA processing (Sqs1 and Pxr1). While otherwise dissimilar in primary sequence, these Prp43-binding proteins each contain a short glycine-rich G-patch motif required for function and thought to act in protein or nucleic acid recognition. Here yeast two-hybrid, domain-swap, and site-directed mutagenesis approaches are used to investigate G-patch domain activity and portability. Our results reveal that the Spp382, Sqs1, and Pxr1 G-patches differ in Prp43 two-hybrid response and in the ability to reconstitute the Spp382 and Pxr1 RNA processing factors. G-patch protein reconstitution did not correlate with the apparent strength of the Prp43 two-hybrid response, suggesting that this domain has function beyond that of a Prp43 tether. Indeed, while critical for Pxr1 activity, the Pxr1 G-patch appears to contribute little to the yeast two-hybrid interaction. Conversely, deletion of the primary Prp43 binding site within Pxr1 (amino acids 102–149) does not impede rRNA processing but affects small nucleolar RNA (snoRNA) biogenesis, resulting in the accumulation of slightly extended forms of select snoRNAs, a phenotype unexpectedly shared by the prp43 loss-of-function mutant. These and related observations reveal differences in how the Spp382, Sqs1, and Pxr1 proteins interact with Prp43 and provide evidence linking G-patch identity with pathway-specific DExD/H-box helicase activity.     

The Aggregation-Prone Intracellular Serpin SRP-2 Fails to Transit the ER in Caenorhabditis elegans

Familial encephalopathy with neuroserpin inclusions bodies (FENIB) is a serpinopathy that induces a rare form of presenile dementia. Neuroserpin contains a classical signal peptide and like all extracellular serine proteinase inhibitors (serpins) is secreted via the endoplasmic reticulum (ER)–Golgi pathway. The disease phenotype is due to gain-of-function missense mutations that cause neuroserpin to misfold and aggregate within the ER. In a previous study, nematodes expressing a homologous mutation in the endogenous Caenorhabditis elegans serpin, srp-2, were reported to model the ER proteotoxicity induced by an allele of mutant neuroserpin. Our results suggest that SRP-2 lacks a classical N-terminal signal peptide and is a member of the intracellular serpin family. Using confocal imaging and an ER colocalization marker, we confirmed that GFP-tagged wild-type SRP-2 localized to the cytosol and not the ER. Similarly, the aggregation-prone SRP-2 mutant formed intracellular inclusions that localized to the cytosol. Interestingly, wild-type SRP-2, targeted to the ER by fusion to a cleavable N-terminal signal peptide, failed to be secreted and accumulated within the ER lumen. This ER retention phenotype is typical of other obligate intracellular serpins forced to translocate across the ER membrane. Neuroserpin is a secreted protein that inhibits trypsin-like proteinase. SRP-2 is a cytosolic serpin that inhibits lysosomal cysteine peptidases. We concluded that SRP-2 is neither an ortholog nor a functional homolog of neuroserpin. Furthermore, animals expressing an aggregation-prone mutation in SRP-2 do not model the ER proteotoxicity associated with FENIB.     

Genetics of Lipid-Storage Management in Caenorhabditis elegans Embryos

Lipids play a pivotal role in embryogenesis as structural components of cellular membranes, as a source of energy, and as signaling molecules. On the basis of a collection of temperature-sensitive embryonic lethal mutants, a systematic database search, and a subsequent microscopic analysis of >300 interference RNA (RNAi)–treated/mutant worms, we identified a couple of evolutionary conserved genes associated with lipid storage in Caenorhabditis elegans embryos. The genes include cpl-1 (cathepsin L–like cysteine protease), ccz-1 (guanine nucleotide exchange factor subunit), and asm-3 (acid sphingomyelinase), which is closely related to the human Niemann-Pick disease–causing gene SMPD1. The respective mutant embryos accumulate enlarged droplets of neutral lipids (cpl-1) and yolk-containing lipid droplets (ccz-1) or have larger genuine lipid droplets (asm-3). The asm-3 mutant embryos additionally showed an enhanced resistance against C band ultraviolet (UV-C) light. Herein we propose that cpl-1, ccz-1, and asm-3 are genes required for the processing of lipid-containing droplets in C. elegans embryos. Owing to the high levels of conservation, the identified genes are also useful in studies of embryonic lipid storage in other organisms.     

A Conserved GEF for Rho-Family GTPases Acts in an EGF Signaling Pathway to Promote Sleep-like Quiescence in Caenorhabditis elegans

Sleep is evolutionarily conserved and required for organism homeostasis and survival. Despite this importance, the molecular and cellular mechanisms underlying sleep are not well understood. Caenorhabditis elegans exhibits sleep-like behavioral quiescence and thus provides a valuable, simple model system for the study of cellular and molecular regulators of this process. In C. elegans, epidermal growth factor receptor (EGFR) signaling is required in the neurosecretory neuron ALA to promote sleep-like behavioral quiescence after cellular stress. We describe a novel role for VAV-1, a conserved guanine nucleotide exchange factor (GEF) for Rho-family GTPases, in regulation of sleep-like behavioral quiescence. VAV-1, in a GEF-dependent manner, acts in ALA to suppress locomotion and feeding during sleep-like behavioral quiescence in response to cellular stress. Additionally, VAV-1 activity is required for EGF-induced sleep-like quiescence and normal levels of EGFR and secretory dense core vesicles in ALA. Importantly, the role of VAV-1 in promoting cellular stress–induced behavioral quiescence is vital for organism health because VAV-1 is required for normal survival after cellular stress.     

Asymmetric Wnt Pathway Signaling Facilitates Stem Cell-Like Divisions via the Nonreceptor Tyrosine Kinase FRK-1 in Caenorhabditis elegans

Asymmetric cell division is critical during development, as it influences processes such as cell fate specification and cell migration. We have characterized FRK-1, a homolog of the mammalian Fer nonreceptor tyrosine kinase, and found it to be required for differentiation and maintenance of epithelial cell types, including the stem cell-like seam cells of the hypodermis. A genomic knockout of frk-1, allele ok760, results in severely uncoordinated larvae that arrest at the L1 stage and have an excess number of lateral hypodermal cells that appear to have lost asymmetry in the stem cell-like divisions of the seam cell lineage. frk-1(ok760) mutants show that there are excess lateral hypodermal cells that are abnormally shaped and smaller in size compared to wild type, a defect that could be rescued only in a manner dependent on the kinase activity of FRK-1. Additionally, we observed a significant change in the expression of heterochronic regulators in frk-1(ok760) mutants. However, frk-1(ok760) mutants do not express late, nonseam hypodermal GFP markers, suggesting the seam cells do not precociously differentiate as adult-hyp7 cells. Finally, our data also demonstrate a clear role for FRK-1 in seam cell proliferation, as eliminating FRK-1 during the L3–L4 transition results in supernumerary seam cell nuclei that are dependent on asymmetric Wnt signaling. Specifically, we observe aberrant POP-1 and WRM-1 localization that is dependent on the presence of FRK-1 and APR-1. Overall, our data suggest a requirement for FRK-1 in maintaining the identity and proliferation of seam cells primarily through an interaction with the asymmetric Wnt pathway.     

Genome sequence and description of Aeromicrobium massiliense sp. nov.

Aeromicrobium massiliense strain JC14^Tsp. nov. is the type strain of Aeromicrobium massiliense sp. nov., a new species within the genus Aeromicrobium. This strain, whose genome is described here, was isolated from the fecal microbiota of an asymptomatic patient. Aeromicrobium massiliense is an aerobic rod-shaped gram-positive bacterium. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,322,119 bp long genome contains 3,296 protein-coding and 51 RNA genes.     

Genome sequence and description of Alistipes senegalensis sp. nov.

Alistipes senegalensis strain JC50^T is the type strain of A. senegalensis sp. nov., a new species within the Alistipes genus. This strain, whose genome is described here, was isolated from the fecal flora of an asymptomatic patient. A. senegalensis is an anaerobic Gram-negative rod-shaped bacterium. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 4,017,609 bp long genome (1 chromosome, but no plasmid) contains 3,113 protein-coding and 50 RNA genes, including 5 rRNA genes.     

Mechanisms of Ephrin Receptor Protein Kinase-Independent Signaling in Amphid Axon Guidance in Caenorhabditis elegans

Eph receptors and their ephrin ligands are key conserved regulators of axon guidance and can function in a variety of signaling modes. Here we analyze the genetic and cellular requirements for Eph signaling in a Caenorhabditis elegans axon guidance choice point, the ventral guidance of axons in the amphid commissure. The C. elegans Eph receptor EFN-1 has both kinase-dependent and kinase-independent roles in amphid ventral guidance. Of the four C. elegans ephrins, we find that only EFN-1 has a major role in amphid axon ventral guidance, and signals in both a receptor kinase-dependent and kinase-independent manner. Analysis of EFN-1 and EFN-1 expression and tissue-specific requirements is consistent with a model in which VAB-1 acts in amphid neurons, interacting with EFN-1 expressed on surrounding cells. Unexpectedly, left-hand neurons are more strongly affected than right-hand neurons by loss of Eph signaling, indicating a previously undetected left–right asymmetry in the requirement for Eph signaling. By screening candidate genes involved in Eph signaling, we find that the Eph kinase-independent pathway involves the ABL-1 nonreceptor tyrosine kinase and possibly the phosphatidylinositol 3-kinase pathway. Overexpression of ABL-1 is sufficient to rescue EFN-1 ventral guidance defects cell autonomously. Our results reveal new aspects of Eph signaling in a single axon guidance decision in vivo.     

Comparative Analysis of Pdf-Mediated Circadian Behaviors Between Drosophila melanogaster and D. virilis

PAR proteins (partitioning defective) are major regulators of cell polarity and asymmetric cell division. One of the par genes, par-1, encodes a Ser/Thr kinase that is conserved from yeast to mammals. In Caenorhabditis elegans, par-1 governs asymmetric cell division by ensuring the polar distribution of cell fate determinants. However the precise mechanisms by which PAR-1 regulates asymmetric cell division in C. elegans remain to be elucidated. We performed a genomewide RNAi screen and identified six genes that specifically suppress the embryonic lethal phenotype associated with mutations in par-1. One of these suppressors is mpk-1, the C. elegans homolog of the conserved mitogen activated protein (MAP) kinase ERK. Loss of function of mpk-1 restored embryonic viability, asynchronous cell divisions, the asymmetric distribution of cell fate specification markers, and the distribution of PAR-1 protein in par-1 mutant embryos, indicating that this genetic interaction is functionally relevant for embryonic development. Furthermore, disrupting the function of other components of the MAPK signaling pathway resulted in suppression of par-1 embryonic lethality. Our data therefore indicates that MAP kinase signaling antagonizes PAR-1 signaling during early C. elegans embryonic polarization.ASYMMETRIC cell division, a process in which a mother cell divides in two different daughter cells, is a fundamental mechanism to achieve cell diversity during development. We use the early embryo of Caenorhabditis elegans as a model system to study asymmetric cell division. The C. elegans one-cell embryo divides asymmetrically along its anteroposterior axis, generating two cells of different sizes and fates: the larger anterior daughter cell will generate somatic tissues while the smaller posterior daughter cell will generate the germline (Sulston et al. 1983).A group of proteins called PAR proteins (partitioning defective) is required for asymmetric cell division in C. elegans (Kemphues et al. 1988). Depletion of any of the seven par genes (par-1 to -6 and pkc-3) leads to defects in asymmetric cell division and embryonic lethality (Kemphues et al. 1988; Kirby et al. 1990; Tabuse et al. 1998; Hung and Kemphues 1999; Hao et al. 2006). PAR-3 and PAR-6 are conserved proteins that contain PDZ-domains and form a complex with PKC-3 (Etemad-Moghadam et al. 1995; Izumi et al. 1998; Tabuse et al. 1998; Hung and Kemphues 1999). This complex becomes restricted to the anterior cortex of the embryo in response to spatially defined actomyosin contractions occurring in the embryo upon fertilization (Goldstein and Hird 1996; Munro et al. 2004). The posterior cortex of the embryo that becomes devoid of the anterior PAR proteins is occupied by the RING protein PAR-2 and the Ser/Thr kinase PAR-1 (Guo and Kemphues 1995; Boyd et al. 1996; Cuenca et al. 2003). Once polarized, the anterior and posterior PAR proteins mutually exclude each other from their respective cortices (Etemad-Moghadam et al. 1995; Boyd et al. 1996; Cuenca et al. 2003; Hao et al. 2006). Loss of function of the gene par-1, as opposed to loss of most other par genes, results in embryos that exhibit only subtle effects on the polarized cortical domains occupied by the other PAR proteins (Cuenca et al. 2003). However defects in this gene are associated with a more symmetric division in size, an aberrant distribution of cell fate specification markers, altered cell fates of the daughter cells of the embryo, and ultimately embryonic lethality (Kemphues et al. 1988; Guo and Kemphues 1995).PAR-1 controls asymmetric cell division and cell fate specification by regulating the localization of the two highly similar CCCH-type zinc-finger proteins MEX-5 and MEX-6 (referred to as MEX-5/6). MEX-5 and MEX-6 are 70% identical in their amino acid sequence and fulfill partially redundant functions in the embryo (Schubert et al. 2000). In wild-type animals, endogenous MEX-5 and GFP fusions of MEX-6 localize primarily to the anterior of the embryo while both proteins are evenly distributed in par-1 mutant embryos (Schubert et al. 2000; Cuenca et al. 2003). This suggests that in wild-type animals, PAR-1 acts in part by restricting MEX-5 and MEX-6 to the anterior of the embryo. The precise mechanism of this regulation is not known, but an elegant study performed for MEX-5 indicates that differential protein mobility in the anterior and posterior cytoplasm of the one-cell embryo contributes to this asymmetry (Tenlen et al. 2008). While increased mobility in the posterior of the one-cell embryo correlates with a par-1- and par-4-dependent phosphorylation on MEX-5, the kinase directly phosphorylating MEX-5 remains to be identified (Tenlen et al. 2008).Some of the phenotypes associated with loss of par-1 function are dependent on the function of mex-5 and mex-6. First, loss of function of par-1 leads to a decreased stability and aberrant localization of the posterior cell fate specification marker PIE-1, a protein that is usually inherited by the posterior daughter cell in wild-type animals and ensures the correct specification of the germline (Mello et al. 1996; Seydoux et al. 1996). This decreased stability is dependent on mex-5/6 function as PIE-1 levels are restored, albeit with symmetrical distribution, in mex-6(RNAi); mex-5(RNAi); par-1(b274) embryos (Schubert et al. 2000; Cuenca et al. 2003; Derenzo et al. 2003). Second, embryos lacking par-1 function exhibit decreased amounts of P granules in the one-cell embryo, while these markers are present in mex-6(pk440); mex-5(zu199); par-1(RNAi) embryos of comparable age (Cheeks et al. 2004). Third, in par-1(RNAi) one-cell embryos the posterior cortical domain occupied by the polarity protein PAR-2 is extended anteriorly, when compared to wild-type embryos (Cuenca et al. 2003). This anterior extension is rescued in embryos deficient for both par-1 and mex-5/6 (Cuenca et al. 2003). Taken together, these results indicate that par-1 acts in the embryo—at least in part—by regulating the localization and/or activity of the proteins MEX-5 and MEX-6. However, it remains unclear whether other proteins can modulate PAR-1 function to affect MEX-5/6 activity.To gain insight into the mechanisms of par-1 function in the embryo, we sought to identify genes that act together with par-1 during embryonic development. We performed an RNAi-based screen for genetic interactors of the temperature-sensitive allele par-1(zu310), using the embryonic lethal phenotype of this mutant as a readout. This method has proven successful in previous screens to identify genes involved in early embryonic processes (Labbé et al. 2006; O''Rourke et al. 2007). We were able to identify six genes that, upon disruption of their function, suppress the embryonic lethal phenotype of par-1 mutant embryos. One of these genes is mpk-1, the C. elegans homolog of the highly conserved MAP kinase ERK. Closer analysis subsequently showed that reduction of function of mpk-1 not only increases viability of par-1 mutant embryos, but also reverts several polarity phenotypes associated with loss of function of par-1. Our data indicate that mpk-1 antagonizes par-1 activity to regulate polarization and asymmetric cell divisions in the early embryo.     

Non-contiguous finished genome sequence and description of Brevibacterium senegalense sp. nov.

Brevibacterium senegalense strain JC43^T sp. nov. is the type strain of Brevibacterium senegalense sp. nov., a new species within the Brevibacterium genus. This strain, whose genome is described here, was isolated from the fecal flora of a healthy Senegalese patient. B. senegalense is an aerobic rod-shaped Gram-positive bacterium. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,425,960 bp long genome (1 chromosome but no plasmid) contains 3,064 protein-coding and 49 RNA genes.     

New Insights into the Post-Translational Regulation of DNA Damage Response and Double-Strand Break Repair in Caenorhabditis elegans

Although a growing number of studies have reported the importance of SUMOylation in genome maintenance and DNA double-strand break repair (DSBR), relevant target proteins and how this modification regulates their functions are yet to be clarified. Here, we analyzed SUMOylation of ZTF-8, the homolog of mammalian RHINO, to test the functional significance of this protein modification in the DSBR and DNA damage response (DDR) pathways in the Caenorhabditis elegans germline. We found that ZTF-8 is a direct target for SUMOylation in vivo and that its modification is required for DNA damage checkpoint induced apoptosis and DSBR. Non-SUMOylatable mutants of ZTF-8 mimic the phenotypes observed in ztf-8 null mutants, including reduced fertility, impaired DNA damage repair, and defective DNA damage checkpoint activation. However, while mutants for components acting in the SUMOylation pathway fail to properly localize ZTF-8, its localization is not altered in the ZTF-8 non-SUMOylatable mutants. Taken together, these data show that direct SUMOylation of ZTF-8 is required for its function in DSBR as well as DDR but not its localization. ZTF-8’s human ortholog is enriched in the germline, but its meiotic role as well as its post-translational modification has never been explored. Therefore, our discovery may assist in understanding the regulatory mechanism of this protein in DSBR and DDR in the germline.     

Systematic Analyses of rpm-1 Suppressors Reveal Roles for ESS-2 in mRNA Splicing in Caenorhabditis elegans

The PHR (Pam/Highwire/RPM-1) family of ubiquitin E3 ligases plays conserved roles in axon patterning and synaptic development. Genetic modifier analysis has greatly aided the discovery of the signal transduction cascades regulated by these proteins. In Caenorhabditis elegans, loss of function in rpm-1 causes axon overgrowth and aberrant presynaptic morphology, yet the mutant animals exhibit little behavioral deficits. Strikingly, rpm-1 mutations strongly synergize with loss of function in the presynaptic active zone assembly factors, syd-1 and syd-2, resulting in severe locomotor deficits. Here, we provide ultrastructural evidence that double mutants, between rpm-1 and syd-1 or syd-2, dramatically impair synapse formation. Taking advantage of the synthetic locomotor defects to select for genetic suppressors, previous studies have identified the DLK-1 MAP kinase cascade negatively regulated by RPM-1. We now report a comprehensive analysis of a large number of suppressor mutations of this screen. Our results highlight the functional specificity of the DLK-1 cascade in synaptogenesis. We also identified two previously uncharacterized genes. One encodes a novel protein, SUPR-1, that acts cell autonomously to antagonize RPM-1. The other affects a conserved protein ESS-2, the homolog of human ES2 or DGCR14. Loss of function in ess-2 suppresses rpm-1 only in the presence of a dlk-1 splice acceptor mutation. We show that ESS-2 acts to promote accurate mRNA splicing when the splice site is compromised. The human DGCR14/ES2 resides in a deleted chromosomal region implicated in DiGeorge syndrome, and its mutation has shown high probability as a risk factor for schizophrenia. Our findings provide the first functional evidence that this family of proteins regulate mRNA splicing in a context-specific manner.     

Complete genome sequence of the motile actinomycete Actinoplanes missouriensis 431T (= NBRC 102363T)

Actinoplanes missouriensis Couch 1963 is a well-characterized member of the genus Actinoplanes, which is of morphological interest because its members typically produce sporangia containing motile spores. The sporangiospores are motile by means of flagella and exhibit chemotactic properties. It is of further interest that members of Actinoplanes are prolific sources of novel antibiotics, enzymes, and other bioactive compounds. Here, we describe the features of A. missouriensis 431^T, together with the complete genome sequence and annotation. The 8,773,466 bp genome contains 8,125 protein-coding and 79 RNA genes.     

Coordination of Recombination with Meiotic Progression in the Caenorhabditis elegans Germline by KIN-18, a TAO Kinase That Regulates the Timing of MPK-1 Signaling

Meiosis is a tightly regulated process requiring coordination of diverse events. A conserved ERK/MAPK-signaling cascade plays an essential role in the regulation of meiotic progression. The Thousand And One kinase (TAO) kinase is a MAPK kinase kinase, the meiotic role of which is unknown. We have analyzed the meiotic functions of KIN-18, the homolog of mammalian TAO kinases, in Caenorhabditis elegans. We found that KIN-18 is essential for normal meiotic progression; mutants exhibit accelerated meiotic recombination as detected both by analysis of recombination intermediates and by crossover outcome. In addition, ectopic germ-cell differentiation and enhanced levels of apoptosis were observed in kin-18 mutants. These defects correlate with ectopic activation of MPK-1 that includes premature, missing, and reoccurring MPK-1 activation. Late progression defects in kin-18 mutants are suppressed by inhibiting an upstream activator of MPK-1 signaling, KSR-2. However, the acceleration of recombination events observed in kin-18 mutants is largely MPK-1-independent. Our data suggest that KIN-18 coordinates meiotic progression by modulating the timing of MPK-1 activation and the progression of recombination events. The regulation of the timing of MPK-1 activation ensures the proper timing of apoptosis and is required for the formation of functional oocytes. Meiosis is a conserved process; thus, revealing that KIN-18 is a novel regulator of meiotic progression in C. elegans would help to elucidate TAO kinase’s role in germline development in higher eukaryotes.     

Tissue-Specific Activation of a Single Gustatory Receptor Produces Opposing Behavioral Responses in Drosophila

Understanding sensory systems that perceive environmental inputs and neural circuits that select appropriate motor outputs is essential for studying how organisms modulate behavior and make decisions necessary for survival. Drosophila melanogaster oviposition is one such important behavior, in which females evaluate their environment and choose to lay eggs on substrates they may find aversive in other contexts. We employed neurogenetic techniques to characterize neurons that influence the choice between repulsive positional and attractive egg-laying responses toward the bitter-tasting compound lobeline. Surprisingly, we found that neurons expressing Gr66a, a gustatory receptor normally involved in avoidance behaviors, receive input for both attractive and aversive preferences. We hypothesized that these opposing responses may result from activation of distinct Gr66a-expressing neurons. Using tissue-specific rescue experiments, we found that Gr66a-expressing neurons on the legs mediate positional aversion. In contrast, pharyngeal taste cells mediate the egg-laying attraction to lobeline, as determined by analysis of mosaic flies in which subsets of Gr66a neurons were silenced. Finally, inactivating mushroom body neurons disrupted both aversive and attractive responses, suggesting that this brain structure is a candidate integration center for decision-making during Drosophila oviposition. We thus define sensory and central neurons critical to the process by which flies decide where to lay an egg. Furthermore, our findings provide insights into the complex nature of gustatory perception in Drosophila. We show that tissue-specific activation of bitter-sensing Gr66a neurons provides one mechanism by which the gustatory system differentially encodes aversive and attractive responses, allowing the female fly to modulate her behavior in a context-dependent manner.     

Complete genome sequence of the sulfate-reducing firmicute Desulfotomaculum ruminis type strain (DLT)

Desulfotomaculum ruminis Campbell and Postgate 1965 is a member of the large genus Desulfotomaculum which contains 30 species and is contained in the family Peptococcaceae. This species is of interest because it represents one of the few sulfate-reducing bacteria that have been isolated from the rumen. Here we describe the features of D. ruminis together with the complete genome sequence and annotation. The 3,969,014 bp long chromosome with a total of 3,901 protein-coding and 85 RNA genes is the second completed genome sequence of a type strain of the genus Desulfotomaculum to be published, and was sequenced as part of the DOE Joint Genome Institute Community Sequencing Program 2009.Keywords : anaerobic, motile, sporulating, mesophilic, sulfate-reducer, hydrogen sulfide, incomplete oxidizer, mixotrophic, CSP 2009, Peptococcaceae, Clostridiales