Taxonomic status of Kitasatosporia, and proposed unification with Streptomyces on the basis of phenotypic and 16S rRNA analysis and emendation of Streptomyces Waksman and Henrici 1943, 339AL.

Species classified within the genus Kitasatosporia share many of the phenotypic characteristics typical of streptomycetes. By using a probabilistic identification scheme, they were identified with Streptomyces exfoliatus cluster 5, a species group within Streptomyces. The four species studied hybridized with a 16S rRNA genus probe for Streptomyces spp., indicating a close relationship between the two genera. The kitasatosporias were resistant to selected polyvalent streptomycete phages tested. Quantitative analysis showed that meso-diaminopimelic acid varied from 49 to 89% in Kitasatosporia species and from 1 to 16% in Streptomyces species depending on growth conditions. On the basis of 16S rRNA analysis, it is proposed to reduce Kitasatosporia to synonymy with Streptomyces. As a result, the new names proposed are Streptomyces mediocidicus comb. nov., Streptomyces phosalacineus comb. nov., Streptomyces setae comb. nov., and Streptomyces griseolosporeus comb. nov., nom. nov.     

An electron microscopical study of epididymal epithelium of rats treated with gonadotropic hormone

The ultrastructural modifications of the epithelial cells of rat corpus epididymis stimulated with gonadotropic hormone were studied. The structural variety of the cells depending on functional conditions becomes more prominent 6 h after the injection of gonadotropic hormone. Light large cells have one or often two nucleus-containing bing nucleoli, in their cytoplasm there are numerous vesicles, a well-developed Golgi apparatus, other organelles and lysosomal bodies. Some other cells are filled with many large vacuoles of different density, dense bodies and vesicles. Cells of another type which are in the majority show an unusually active structure reflecting the function of synthesis. The more prominent nucleolus is associated to clumps of chromatin. Their apical cytoplasm is filled by a structure related to absorption. The whole remaining part of their cytoplasm is covered with a very extensive Golgi apparatus and a very well developed granular endoplasmic reticulum. The extremely enlarged cisternae of this reticulum were found to be very closely applied to the basal cell membrane. There is a flocculent material inside the cisternae. Similar material is observed in the extracellular medium under the basal membrane. The epithelium seems normal 10 h after the injection of hormone, but large light cells make up the majority of them.     

Phylogenetic Analysis of Bradyrhizobium japonicum and Photosynthetic Stem-Nodulating Bacteria from Aeschynomene Species Grown in Separated Geographical Regions

Nearly complete and short partial 16S rRNA sequences were derived from PCR-amplified ribosomal DNAs of Bradyrhizobium japonicum USDA 136 and USDA 110 and five strains of bacteriochlorophyll-synthesizing bacteria isolated from stem nodules of Aeschynomene indica and other Aeschynomene species growing in different geographic regions, including India, The Philippines and North America. We confirmed that the five stem-nodulating strains examined synthesize bacteriochlorophyll a, and the absorption spectra of methanol-extracted cells contained a major absorbance peak at 770 nm. Strains isolated on different continents and from different Aeschynomene species were found to be phylogenetically homogeneous and exhibited levels of sequence similarity of more than 99%. The bacteriochlorophyll-synthesizing rhizobia, Bradyrhizobium japonicum, Blastobacter denitrificans, Afipia felis, and Rhodopseudomonas palustris exhibited levels of sequence similarity of 97% or greater and belong to a distinct line of descent within the alpha-2 subdivision of the Proteobacteria. Variable regions between positions 995 and 1045 provide potential target sites for design of a probe that is able to distinguish the photosynthetic rhizobia from closely related taxa.     

Endosymbiosis in statu nascendi: close phylogenetic relationship between obligately endosymbiotic and obligately free-living Polynucleobacter strains (Betaproteobacteria)

Bacterial strains affiliated to the phylogenetically shallow subcluster C (PnecC) of the Polynucleobacter cluster, which is characterized by a minimal 16S rRNA gene sequence similarity of approximately 98.5%, have been reported to occur as obligate endosymbionts of ciliates (Euplotes spp.), as well as to occur as free-living cells in the pelagic zone of freshwater habitats. We investigated if these two groups of closely related bacteria represent strains fundamentally differing in lifestyle, or if they simply represent different stages of a facultative endosymbiotic lifestyle. The phylogenetic analysis of 16S rRNA gene and 16S-23S ITS sequences of five endosymbiont strains from two different Euplotes species and 40 pure culture strains demonstrated host-species-specific clustering of the endosymbiont sequences within the PnecC subcluster. The sequences of the endosymbionts showed characteristics indicating an obligate endosymbiotic lifestyle. Cultivation experiments revealed fundamental differences in physiological adaptations, and determination of the genome sizes indicated a slight size reduction in endosymbiotic strains. We conclude that the two groups of PnecC bacteria represent obligately free-living and obligately endosymbiotic strains, respectively, and do not represent different stages of the same complex life cycle. These closely related strains occupy completely separated ecological niches. To our best knowledge, this is the closest phylogenetic relationship between obligate endosymbionts and obligately free-living bacteria ever revealed.     

<Emphasis Type="Italic">Porphyrobacter meromictius</Emphasis> sp. nov., an Appendaged Bacterium,That Produces Bacteriochlorophyll <Emphasis Type="Italic">a</Emphasis>

Four Gram-negative strains (ML4(T), ML19, ML31, ML32) of nonmotile, appendaged, budding bacteria were isolated from the meromictic Mahoney Lake in British Columbia, Canada. The strains were red to brown-red in color and produced bacteriochlorophyll a incorporated into photosynthetic pigment-protein complexes. Phylogenetic analysis has placed these strains within the class Alphaproteobacteria, with the closest relatives being members of the genera Erythrobacter, Porphyrobacter, and Erythromicrobium. Morphological features warrant their inclusion within the genus Porphyrobacter and these strains can be readily distinguished from other species of this genus on the basis of a mesophilic temperature range, a broad pH range, and tolerance to extremely high NaCl and Na(2)SO(4) concentrations, in keeping with the environment from which they were isolated, a Na(2)SO(4)-dominated meromictic lake. These isolates utilize a variety of organic substrates for aerobic chemoheterotrophic growth and do not grow under anaerobic conditions, in either the presence or the absence of light. All strains require vitamin B(12), and strains ML4(T) and ML19 require biotin. The DNA G + C contents ranged from 62.2 to 64.9 mol%. Phenotypic and phyletic data support the classification of strains ML4(T), ML19, ML31, and ML32 as a novel Porphyrobacter species for which the name Porphyrobacter meromictius sp. nov. is proposed.     

Diagnosis of Schistosoma infection in non-human animal hosts: A systematic review and meta-analysis

BackgroundReliable and field-applicable diagnosis of schistosome infections in non-human animals is important for surveillance, control, and verification of interruption of human schistosomiasis transmission. This study aimed to summarize uses of available diagnostic techniques through a systematic review and meta-analysis.Methodology and principal findingsWe systematically searched the literature and reports comparing two or more diagnostic tests in non-human animals for schistosome infection. Out of 4,909 articles and reports screened, 19 met our inclusion criteria, four of which were considered in the meta-analysis. A total of 14 techniques (parasitologic, immunologic, and molecular) and nine types of non-human animals were involved in the studies. Notably, four studies compared parasitologic tests (miracidium hatching test (MHT), Kato-Katz (KK), the Danish Bilharziasis Laboratory technique (DBL), and formalin-ethyl acetate sedimentation-digestion (FEA-SD)) with quantitative polymerase chain reaction (qPCR), and sensitivity estimates (using qPCR as the reference) were extracted and included in the meta-analyses, showing significant heterogeneity across studies and animal hosts. The pooled estimate of sensitivity was 0.21 (95% confidence interval (CI): 0.03–0.48) with FEA-SD showing highest sensitivity (0.89, 95% CI: 0.65–1.00).Conclusions/significanceOur findings suggest that the parasitologic technique FEA-SD and the molecular technique qPCR are the most promising techniques for schistosome diagnosis in non-human animal hosts. Future studies are needed for validation and standardization of the techniques for real-world field applications.     

16S ribosomal RNA- and cell wall analysis of Gemmata obscuriglobus, a new member of the order Planctomycetales

Abstract Gemmata obscuriglobus UQM2246 was investigated by the 16S ribosomal RNA cataloguing approach in order to determine its phylogenetic position. This budding organism is a member of the order Planctomycetales, displaying a remote and equidistant relationship to representatives of the genera Planctomyces and Pirella . Like the other members of this order, G. obscuriglobus lacks peptidoglycan, possessing a proteinaceous cell wall instead.