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At least 19 recordsLinked to original sources
PubMed2006

The geographic distribution of the putative agent of epizootic bovine abortion in the tick vector, Ornithodoros coriaceus.

Epizootic bovine abortion (EBA), also known as "foothill abortion", is a vector borne disease of beef cattle that graze in the mountainous regions of California, southern Oregon and western Nevada transmitted by the argasid tick Ornithodoros coriaceus. Recently, the putative agent of EBA was identified as a novel Deltaproteobacter in the order Myxococcales. In this study, a TaqMan real-time PCR (TM-PCR) protocol specific to the putative EBA agent was developed. The new real-time TM-PCR assay functioned sensitively and specifically to detect pathogen DNA in field-collected O. coriaceus ticks. The assay had an analytical sensitivity of a single plasmid copy and, when evaluated with a collection of tick-borne pathogens, yielded a positive PCR-result only for the agent of EBA. Use of the TM-PCR represents an effective tool for rapid and highly sensitive assessment of environmental risk and spatial and statistical analysis to highlight areas where there may be increased risk for EBA in susceptible cattle.

Abortion, Veterinary↗
PubMed1999

The correlation between morphological and phylogenetic classification of myxobacteria.

In order to determine whether morphological criteria are suitable to affiliate myxobacterial strains to species, a phylogenetic analysis of 16S rDNAs was performed on 54 myxobacterial strains that represented morphologically 21 species of the genera Angiococcus, Archangium, Chondromyces, Cystobacter, Melittangium, Myxococcus, Polyangium and Stigmatella, five invalid species and three unclassified isolates. The analysis included 12 previously published sequences. The branching pattern confirmed the deep trifurcation of the order Myxococcales. One lineage is defined by the genera Cystobacter, Angiococcus, Archangium, Melittangium, Myxococcus and Stigmatella. The study confirms the genus status of 'Corallococcus', previously 'Chondrococcus', within the family Myxococcaceae. The second lineage contains the genus Chondromyces and the species Polyangium ('Sorangium') cellulosum, while the third lineage is comprised of Nannocystis and a strain identified as Polyangium vitellinum. With the exception of a small number of strains that did not cluster phylogenetically with members of the genus to which they were assigned by morphological criteria ('Polyangium thaxteri' Pl t3, Polyangium cellulosum ATCC 25531T, Melittangium lichenicola ATCC 25947T and Angiococcus disciformis An d1), the phenotypic classification should provide a sound basis for the description of neotype species in those cases where original strain material is not available or is listed as reference material.

Bacterial Typing Techniques↗
PubMed2006

Byssovorax cruenta gen. nov., sp. nov., nom. rev., a cellulose-degrading myxobacterium: rediscovery of 'Myxococcus cruentus' Thaxter 1897.

A rare, cellulose-decomposing myxobacterium is described, and a new genus name, Byssovorax, is proposed for it. The organism is almost certainly identical to the species 'Myxococcus cruentus' Thaxter 1897, and that species epithet is therefore revived for the novel bacterium: the type strain of Byssovorax cruenta gen. nov., sp. nov., nom. rev. is strain By c2(T) (=DSM 14553(T)=CIP 108850(T)). The G+C content of its DNA is 69.9 mol%. The 16S rRNA gene sequence shows that the species belongs to the family Polyangiaceae, suborder 'Sorangineae', of the Myxococcales. An emended description of the organism is given.

Base Composition↗
PubMed2024

Putative evolution of Myxococcus fulvus 124B02 plasmid pMF1 from a chromosomal segment in another Myxococcus species.

Myxobacteria or order Myxococcales (old nomenclature) or phylum Myxococcota (new terminology) are fascinating organisms well known for their diverse peculiar physiological, taxonomic, and genomic properties. Researchers have long sought to identify plasmids within these organisms, yet thus far, only two organisms from different families have been found to harbor a plasmid. This study delves into the putative evolution of one of these plasmids, i.e., pMF1 present in Myxococcus fulvus 124B02 in the suborder Cystobacterineae and family Myxococcaceae. Here, we first reannotated the pMF1 plasmid genome sequence and identified two additional open reading frames or putative genes which were not annotated until now. We further reported that all pMF1 plasmid genes depict homology with Myxococcus stipitatus CYD1 draft genome (contig 28) and a chromosomal segment of M. stipitatus DSM14675 in a syntenic manner, implying the presence of plasmid-like structure in M. stipitatus CYD1, integrated into its chromosome. To comprehend the relationship among these three species, we conducted phylogenetic analyses using 16S and concatenated housekeeping genes and genome-to-genome distance calculator (GGDC) analysis, which confirmed that M. stipitatus CYD1 is a distinct and novel species within the genus Myxococcus. Overall, this comparative genomic study sheds light on the putative emergence of the pMF1 plasmid from a common ancestor of closely related yet distinct species, M. stipitatus CYD1, possibly through the partition from its chromosome as a segment.IMPORTANCEMyxobacteria are not well known to have plasmids. Until now, only two organisms have been shown to have plasmids, raising a pertinent question about how these plasmids evolved randomly within the phylum Myxococcota. The study presented in this manuscript delves into the emergence of the pMF1 plasmid found in Myxococcus fulvus 124B02, a member of the suborder Cystobacterineae and family Myxococcaceae. Our research addresses this intriguing topic of plasmid identification and evolution within myxobacteria, which are a group of fascinating organisms that have garnered significant interest due to their diverse physiological, taxonomic, and genomic properties.

Plasmids↗
PubMed1994

The soraphens: a family of novel antifungal compounds from Sorangium cellulosum (Myxobacteria). I. Soraphen A1 alpha: fermentation, isolation, biological properties.

An antifungal activity was detected in the culture broth of Sorangium cellulosum (Myxococcales), strain So ce26. The activity was excreted into the supernatant during the log and early stationary phase. The active substance was quantitatively bound to XAD absorber resin added to the medium at the beginning of the fermentation. The new secondary metabolite was called soraphen and is of special interest to plant disease control for its inhibitory activity against numerous phytopathogenic fungi.

Antifungal Agents↗
PubMed1995

Ratjadon: a new antifungal compound from Sorangium cellulosum (myxobacteria) production, physio-chemical and biological properties.

An antifungal activity, ratjadon, was detected in the culture broth of Sorangium cellulosum (Myxococcales) strain So ce360. The metabolite was quantitatively bound to the adsorber resin XAD-16, which was added to the medium at the beginning of the fermentation. The antibiotic spectrum was narrow, but some important phytopathogenic fungi, especially species of Oomycetes, were inhibited at very low concentrations.

Animals↗
PubMed1996

Epothilons A and B: antifungal and cytotoxic compounds from Sorangium cellulosum (Myxobacteria). Production, physico-chemical and biological properties.

An antifungal activity against Mucor hiemalis was detected in the culture broth of Sorangium cellulosum (Myxococcales) strain So ce90. The activity was excreted into the supernatant during the log and early stationary phase. When the adsorber resin XAD-16 was added to the culture, the active metabolites were quantitatively bound to the resin. The epothilons showed a high cytotoxicity for animal cells and mimic the biological effects of taxol (BOLLAG et al., Cancer Res. 55: 2325 approximately 2333, 1995).

Animals↗
PubMed2000

[Isolation and identification of myxobacteria].

This paper reported that the authors isolated large numbers of myxobacteria from more than 100 samples collected in many places of China. More than 400 pure strains were obtained. These strains belonged to 10 genera of Myxococcales. The most frequent genera isolated were Myxococcus, Sorangium, Corallococcus, and Cystobacter. Melittangium was seldom isolated. No Chondromyces and Haploangium were found.

Cellulose↗
PubMed2005

Phylogeny of Proteobacteria and Bacteroidetes from oxic habitats of a tidal flat ecosystem.

Bacteria of the phyla Proteobacteria and Bacteroidetes are known to be the most prominent heterotrophic organisms in marine surface waters. In order to investigate the occurrence of these phyla in a coastal environment, the tidal flat ecosystem German Wadden Sea, we analyzed a clone library of PCR-amplified and sequenced 16S rRNA gene fragments and isolated 46 new strains affiliated with these phyla from the water column with various polymers and complex media as substrates. The phylogenetic affiliation of these strains was analyzed on the basis of sequenced 16S rRNA gene fragments. Subsequently, a comprehensive phylogenetic analysis of Proteobacteria and Bacteroidetes including available sequences from oxic habitats of earlier studies of this ecosystem was performed. Sequences of the earlier studies were derived from isolation approaches and from denaturing gradient gel electrophoresis (DGGE) analyses of environmental samples and high dilution steps of MPN (most probable number) cultures. The majority of the 265 sequences included in this analysis affiliated with alpha-Proteobacteria (45.3%), gamma-Proteobacteria (31.7%), and Bacteroidetes (16.2%). Almost 7% belong to the delta-Proteobacteria and several of these clones affiliated with the Myxococcales, a group comprising obligate aerobic organisms. Within the alpha- and gamma-Proteobacteria specific clusters were identified including isolates from high dilution steps of dilution cultures and/or clones from the clone library or DGGE gels, implying a high abundance of some of these organisms. Within the gamma-Proteobacteria a new cluster is proposed, which consists of marine surface-attached organisms. This SAMMIC (Surface Attached Marine MICrobes) cluster comprises only uncultured phylotypes and exhibits a global distribution. Overall, the analysis indicates that Proteobacteria and Bacteroidetes of the Wadden Sea have a surprisingly high diversity, presumably a result of the signature of this ecosystem as a melting pot at the land-sea interface and comprising a great habitat variety.

Bacteroidetes↗
PubMed2005

Succession of bacterial community structure and diversity in a paddy soil oxygen gradient.

Cultivation-independent techniques were applied to assess the succession and phylogenetic composition of bacterial communities in a vertical oxygen gradient in flooded, unplanted paddy soil microcosms. Microsensor measurements showed that within 6 h of flooding, oxygen was depleted from 200 microM at the floodwater-soil interface to undetectable amounts at a depth of approximately 2 mm and below. The gradient was quite stable over time, although the oxygen depletion was less pronounced 84 days than 6 h after flooding. Community fingerprint patterns were obtained by terminal restriction fragment length polymorphism (T-RFLP) analysis from the oxic, transition, and anoxic zones of triplicate soil microcosms at 0, 1 and 6 h, and 1, 2, 7, 21, 30, 42, 84, and 168 days after flooding. Correspondence analyses revealed that T-RFLP patterns obtained using either community DNA or RNA were affected by time and oxygen zone, and that there was a significant interaction between the effects of time and oxygen zone. The temporal dynamics of bacterial populations were resolved more clearly using RNA than using DNA. At the RNA level, successional community dynamics were most pronounced from 1 h to 2 days and less pronounced from 2 to 21 days after flooding, for both oxic and anoxic zones. No effect of time or oxygen zone on the community dynamics was observed from 21 to 168 days after flooding. Dominant early successional populations were identified by cloning and comparative sequence analysis of environmental 16S rRNA and 16S rRNA genes as members of the Betaproteobacteria (oxic zone) and the clostridial cluster I (anoxic zone). Dominant late successional populations belonged to the Verrucomicrobia and Nitrospira (detected mainly in the oxic zone), and to the Myxococcales (detected mainly in the anoxic zone). In conclusion, the bacterial community developed through successional stages, leading at the RNA level to almost stable community patterns within 21 days after flooding. This principal finding, in combination with the phylogenetic identity of early- and late-appearing populations, suggests that the community dynamics can be explained by the principles of r- and K-selection.

Bacteria↗
PubMed2006

How elevated pCO2 modifies total and metabolically active bacterial communities in the rhizosphere of two perennial grasses grown under field conditions.

The response of total (DNA-based analysis) and active (RNA-based analysis) bacterial communities to a pCO2 increase under field conditions was assessed using two perennial grasses: the nitrophilic Lolium perenne and the oligonitrophilic Molinia coerulea. PCR- and reverse transcriptase-PCR denaturing gradient gel electrophoresis analysis of 16S rRNA genes generated contrasting profiles. The pCO2 increase influenced mainly the active and root-associated component of the bacterial community. Bacterial groups responsive to the pCO2 increase were identified by sequencing of corresponding denaturing gradient gel electrophoresis bands. About 50% of retrieved sequences were affiliated to Proteobacteria. Our data suggest that Actinobacteria in soil and Myxococcales (Deltaproteobacteria) in root are stimulated under elevated pCO2.

Actinobacteria↗
PubMed2006

Identification of bacterial micropredators distinctively active in a soil microbial food web.

The understanding of microbial interactions and trophic networks is a prerequisite for the elucidation of the turnover and transformation of organic materials in soils. To elucidate the incorporation of biomass carbon into a soil microbial food web, we added 13C-labeled Escherichia coli biomass to an agricultural soil and identified those indigenous microbes that were specifically active in its mineralization and carbon sequestration. rRNA stable isotope probing (SIP) revealed that uncultivated relatives of distinct groups of gliding bacterial micropredators (Lysobacter spp., Myxococcales, and the Bacteroidetes) lead carbon sequestration and mineralization from the added biomass. In addition, fungal populations within the Microascaceae were shown to respond to the added biomass after only 1 h of incubation and were thus surprisingly reactive to degradable labile carbon. This RNA-SIP study identifies indigenous microbes specifically active in the transformation of a nondefined complex carbon source, bacterial biomass, directly in a soil ecosystem.

Bacteria↗
PubMed2005

Molecular identification of a novel deltaproteobacterium as the etiologic agent of epizootic bovine abortion (foothill abortion).

Epizootic bovine abortion (EBA) is endemic in California's coastal range and the foothill regions of the Sierra Nevada, where it has been the primary diagnosed cause of abortion in beef cattle for >50 years. Investigation of these losses has defined a specific fetal syndrome characterized by late-term abortion or birth of weak or dead calves. Although the unusual clinical presentation and unique fetal pathology associated with EBA have been recognized since the 1950s, the identity of the etiologic agent is unknown. In this study, suppression-hybridization PCR was used to identify a fragment of the 16S rRNA gene of a previously undescribed bacterium in thymus tissue derived from affected fetuses. Phylogenetic analysis revealed that this pathogen was a deltaproteobacterium closely related to members of the order Myxococcales. A specific PCR was subsequently developed to detect the presence of this bacterium in DNA extracted from fetal thymuses. Using histopathology as the definitive diagnosis for EBA, this PCR demonstrated 100% specificity and 88% sensitivity. The bacterium was also detected in the argasid tick Ornithodoros coriaceus, which is the recognized vector of EBA. These data imply a close association between this novel agent and the etiology of EBA.

Abortion, Veterinary↗
PubMed2001

Chondramides, novel cyclodepsipeptides from myxobacteria, influence cell development and induce actin filament polymerization in the green alga Micrasterias.

The effects of chondramides A-D, new actin targeting cyclodepsipeptides from the myxobacterium Chondromyces crocatus, are probed on the unicellular green alga Micrasterias denticulata, a model organism for studies on cytomorphogenesis. All four chondramides readily enter the cells and cause severe shape malformations when applied during growth. However, the four derivatives have different lowest effective concentrations. Chondramide A: 20 microM, chondramide B: 15 microM, chondramide C: 5 microM chondramide D: 10 microM. At the ultrastructural level, chondramide C, the most effective drug, causes the appearance of abnormal, dense F-actin bundles, and a substantial increase in ER, which covers large parts of the developing semicell. Also the secondary cell wall is malformed by the drug. When chondramide C effects are investigated by means of indirect immunofluorescence, alterations of the F-actin system are also visible. Instead of the cortical F-actin network of untreated controls, distinct parts of the cell are covered by abundant F-actin aggregations. Phalloidin staining of chondramide C treated cells results in a decreased fluorescence in a time-dependent manner due to binding competitions between these drugs. F-actin polymerizing and bundling capacities of chondramides A-D are presented in Micrasterias for the first time, and may in future make this substances a useful tool for cell biological research.

Actins↗
PubMed2001

Catalytic antibody route to the naturally occurring epothilones: total synthesis of epothilones A-F.

Naturally occurring epothilones have been synthesized starting from enantiomerically pure aldol compounds 9-11, which were obtained by antibody catalysis. Aldolase antibody 38C2 catalyzed the resolution of (+/-)-9 by enantioselective retro-aldol reaction to afford 9 in 90% ee at 50 % conversion. Compounds 10 and 11 were obtained in more than 99% ee at 50% conversion by resolution of their racemic mixtures using newly developed aldolase antibodies 84G3, 85H6 or 93F3. Compounds 9, 10 and 11 were resolved in multigram quantities and then converted to the epothilones by metathesis processes, which were catalyzed by Grubbs' catalysts.

Anti-Bacterial Agents↗