scholarly journals Characterization of Blood Culture Isolates ofStreptococcus dysgalactiae subsp. equisimilisPossessing Lancefield's Group A Antigen

1999 ◽  
Vol 37 (12) ◽  
pp. 4194-4197 ◽  
Author(s):  
Claudia M. Brandt ◽  
Gerhard Haase ◽  
Norbert Schnitzler ◽  
Reinhard Zbinden ◽  
Rudolf Lütticken
Keyword(s):  
Blood Culture ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Virulence Determinants ◽  
Streptococcus Dysgalactiae ◽  
Genes Encoding ◽  
Group A ◽  
Biochemical Identification ◽  
Species Assignment

For three human blood culture isolates of beta-hemolytic streptococci with Lancefield's serogroup A antigen, phylogenetic analysis of the 16S rRNA genes confirmed biochemical identification asStreptococcus dysgalactiae subsp. equisimilis. Genes encoding M or M-like proteins, which are considered to be major virulence determinants in streptococci, were detected in all of these strains. Our data clearly demonstrate that for beta-hemolytic streptococci, the species assignment should not be based on the results of serogrouping alone.

scholarly journals Taxonomically-linked growth phenotypes during arsenic stress among arsenic resistant bacteria isolated from soils overlying the Centralia coal seam fire

2017 ◽  
Author(s):  
Taylor K Dunivin ◽  
Justine Miller ◽  
Ashley Shade
Keyword(s):  
Coal Seam ◽  
Arsenic Exposure ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Resistant Bacteria ◽  
Rare Biosphere ◽  
Genes Encoding ◽  
Arsenic Resistant Bacteria

Arsenic (As), a toxic element, has impacted life since early Earth. Thus, microorganisms have evolved many As resistance and tolerance mechanisms to improve their survival outcomes given As exposure. We isolated As resistant bacteria from Centralia, PA, the site of an underground coal seam fire that has been burning since 1962. From a 57.4°C soil collected from a vent above the fire, we isolated 25 unique aerobic arsenic resistant bacteria spanning six genera. We examined their diversity, resistance gene content, transformation abilities, inhibitory concentrations, and growth phenotypes. Although As concentrations were low at the time of soil collection (2.58 ppm), isolates had high minimum inhibitory concentrations (MICs) of arsenate and arsenite (>300 mM and 20 mM respectively), and most isolates were capable of arsenate reduction. We screened isolates (PCR and sequencing) using 12 published primer sets for six As resistance genes (AsRG). Genes encoding arsenate reductase (arsC) and arsenite efflux pumps (arsB, ACR3(2)) were present, and phylogenetic incongruence between 16S rRNA genes and AsRG provided evidence for horizontal gene transfer. A detailed investigation of differences in isolate growth phenotypes across As concentrations (lag time to exponential growth, maximum growth rate, and maximum OD590) showed a relationship with taxonomy, providing information that could help to predict an isolate’s performance given arsenic exposure in situ. Our results suggest that considering taxonomically-linked tolerance and potential for resistance transferability from the rare biosphere will inform strategies for microbiological management and remediation of environmental As and contribute to a larger consideration of As-exposed microbial ecology.

Phenotypic and molecular characterization of chickpea rhizobia isolated from different areas of Tunisia

2007 ◽  
Vol 53 (3) ◽  
pp. 427-434 ◽  
Author(s):  
Boulbaba L’taief ◽  
Bouaziz Sifi ◽  
Maher Gtari ◽  
Mainassara Zaman-Allah ◽  
Mokhtar Lachaâl
Keyword(s):  
Rflp Analysis ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Phenotypic Characteristics ◽  
Cicer Arietinum L ◽  
Mesorhizobium Ciceri ◽  
Length Polymorphisms ◽  
Reference Strains ◽  
Tolerance To Salinity

Several phenotypic markers were used in this study to determine the biodiversity of rhizobial strains nodulating Cicer arietinum L. in various areas of Tunisia. They include symbiotic traits, the use of 21 biochemical substrates, and tolerance to salinity and pH. In addition, restriction fragment length polymorphisms (RFLPs) of PCR-amplified 16S rDNA were compared with those of reference strains. Numeric analysis of the phenotypic characteristics showed that the 48 strains studied fell into three distinct groups. This heterogeneity was highly supported by the RFLP analysis of 16S rRNA genes, and two ribotypes were identified. Chickpea rhizobia isolated from Tunisian soils are both phenotypically and genetically diverse. Results showed that 40 and 8 isolates were assigned, respectively, to Mesorhizobium ciceri and Mesorhizobium mediterraneum .

scholarly journals Temporal Variability of Coastal Planctomycetes Clades at Kabeltonne Station, North Sea

2011 ◽  
Vol 77 (14) ◽  
pp. 5009-5017 ◽  
Author(s):  
Ilaria Pizzetti ◽  
Bernhard M. Fuchs ◽  
Gunnar Gerdts ◽  
Antje Wichels ◽  
Karen H. Wiltshire ◽  
...  
Keyword(s):  
16S Rrna ◽  
North Sea ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Content Type ◽  
Group A ◽  
Related Group ◽  
Group B ◽  
Card Fish ◽  
Group D

ABSTRACTMembers of the bacterial phylumPlanctomycetesare reported in marine water samples worldwide, but quantitative information is scarce. Here we investigated the phylogenetic diversity, abundance, and distribution ofPlanctomycetesin surface waters off the German North Sea island Helgoland during different seasons by 16S rRNA gene analysis and catalyzed reporter deposition fluorescencein situhybridization (CARD-FISH). GenerallyPlanctomycetesare more abundant in samples collected in summer and autumn than in samples collected in winter and spring. Statistical analysis revealed thatPlanctomycetesabundance was correlated to theCentralesdiatom bloom in spring 2007. The analysis of size-fractionated seawater samples and of macroaggregates showed that ∼90% of thePlanctomycetesreside in the >3-μm size fraction. Comparative sequence analysis of 184 almost full-length 16S rRNA genes revealed three dominant clades. The clades, namedPlanctomyces-related group A, unculturedPlanctomycetesgroup B, andPirellula-related group D, were monitored by CARD-FISH using newly developed oligonucleotide probes. All three clades showed recurrent abundance patterns during two annual sampling campaigns. UnculturedPlanctomycetesgroup B was most abundant in autumn samples, whilePlanctomyces-related group A was present in high numbers only during late autumn and winter. The levels ofPirellula-related group D were more constant throughout the year, with elevated counts in summer. Our analyses suggest that the seasonal succession of thePlanctomycetesis correlated with algal blooms. We hypothesize that the niche partitioning of the different clades might be caused by their algal substrates.

Genetic characterization of coagulase-positive staphylococci isolated from healthy pigeons

2015 ◽  
Vol 18 (3) ◽  
pp. 627-634 ◽  
Author(s):  
M. Kizerwetter-Świda ◽  
D. Chrobak-Chmiel ◽  
M. Rzewuska ◽  
A. Antosiewicz ◽  
B. Dolka ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Genetic Relatedness ◽  
Genetic Characterization ◽  
Restriction Patterns ◽  
Feral Pigeons ◽  
Group A ◽  
Biochemical Identification ◽  
Group B ◽  
Coagulase Positive Staphylococci

AbstractCoagulase-positive staphylococci (CoPS) are opportunistic veterinary pathogens, of whichStaphylococcus aureus,S. delphiniandS. intermediuscan be isolated from pigeons. The biochemical identification ofS. delphiniandS. intermediusisolates may be incorrect, because of their phenotypic similarity. The purpose of the present study was to isolate and identify CoPS from domestic and feral pigeons and to determine their genetic relatedness by PFGE. A total number of 31 isolates of CoPS were obtained, 15 were identified asS. delphinigroup B, six asS. aureus,four asS. delphinigroup A, three asS. intermediusand three asS. schleiferisubsp.coagulans. The results indicate that S.delphinigroup B is the predominant CoPS species among pigeons studied. PFGE restriction patterns ofS. delphinigroup A andS. delphinigroup B form separate clusters, demonstrating their genetic heterogeneity. Indistinguishable or very similar PFGE patterns observed amongS. delphinigroup B isolates from domestic and feral pigeons confirm the possibility of CoPS transmission between these birds.

scholarly journals Response of Endophytic Bacterial Communities in Potato Plants to Infection with Erwinia carotovora subsp. atroseptica

2002 ◽  
Vol 68 (5) ◽  
pp. 2261-2268 ◽  
Author(s):  
Birgit Reiter ◽  
Ulrike Pfeifer ◽  
Helmut Schwab ◽  
Angela Sessitsch
Keyword(s):  
Plant Stress ◽  
Erwinia Carotovora ◽  
Community Analysis ◽  
Antagonistic Activity ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Polymorphism Analysis ◽  
Blackleg Disease ◽  
Potato Plants

ABSTRACT The term endophyte refers to interior colonization of plants by microorganisms that do not have pathogenic effects on their hosts, and various endophytes have been found to play important roles in plant vitality. In this study, cultivation-independent terminal restriction fragment length polymorphism analysis of 16S ribosomal DNA directly amplified from plant tissue DNA was used in combination with molecular characterization of isolates to examine the influence of plant stress, achieved by infection with the blackleg pathogen Erwinia carotovora subsp. atroseptica, on the endophytic population in two different potato varieties. Community analysis clearly demonstrated increased bacterial diversity in infected plants compared to that in control plants. The results also indicated that the pathogen stress had a greater impact on the bacteria population than the plant genotype had. Partial sequencing of the 16S rRNA genes of isolated endophytes revealed a broad phylogenetic spectrum of bacteria, including members of the α, β, and γ subgroups of the Proteobacteria, high- and low-G+C-content gram-positive organisms, and microbes belonging to the Flexibacter-Cytophaga-Bacteroides group. Screening of the isolates for antagonistic activity against E. carotovora subsp. atroseptica revealed that 38% of the endophytes protected tissue culture plants from blackleg disease.

scholarly journals Expression and Characterization of Streptococcal rgp Genes Required for Rhamnan Synthesis in Escherichia coli

2002 ◽  
Vol 70 (6) ◽  
pp. 2891-2898 ◽  
Author(s):  
Yukie Shibata ◽  
Yoshihisa Yamashita ◽  
Kazuhisa Ozaki ◽  
Yoshio Nakano ◽  
Toshihiko Koga
Keyword(s):  
Escherichia Coli ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Polymerization Process ◽  
Streptococcus Sobrinus ◽  
E Coli ◽  
Genes Encoding ◽  
Group A ◽  
Specific Antigens

ABSTRACT Six genes (rgpA through rgpF) that were involved in assembling the rhamnose-glucose polysaccharide (RGP) in Streptococcus mutans were previously identified (Y. Yamashita, Y. Tsukioka, K. Tomihisa, Y. Nakano, and T. Koga, J. Bacteriol. 180:5803-5807, 1998). The group-specific antigens of Lancefield group A, C, and E streptococci and the polysaccharide antigen of Streptococcus sobrinus have the same rhamnan backbone as the RGP of S. mutans. Escherichia coli harboring plasmid pRGP1 containing all six rgp genes did not synthesize complete RGP. However, E. coli carrying a plasmid with all of the rgp genes except for rgpE synthesized the rhamnan backbone of RGP without glucose side chains, suggesting that in addition to rgpE, another gene is required for glucose side-chain formation. Synthesis of the rhamnan backbone in E. coli required the initiation of transfer of N-acetylglucosamine to a lipid carrier and the expression of the rgpC and rgpD genes encoding the putative ABC transporter specific for RGP. The similarities in RGP synthesis between E. coli and S. mutans suggest common pathways for rhamnan synthesis. Therefore, we evaluated the rhamnosyl polymerization process in E. coli by high-resolution sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the lipooligosaccharide (LOS). An E. coli transformant harboring rgpA produced the LOS modified by the addition of a single rhamnose residue. Furthermore, the rgpA, rgpB, and rgpF genes of pRGP1 were independently mutated by an internal deletion, and the LOS chemotypes of their transformants were examined. The transformant with an rgpA deletion showed the same LOS profile as E. coli without a plasmid. The transformant with an rgpB deletion showed the same LOS profile as E. coli harboring rgpA alone. The transformant with an rgpF deletion showed the LOS band with the most retarded migration. On the basis of these results, we speculated that RgpA, RgpB, and RgpF, in that order, function in rhamnan polymerization.

scholarly journals Abundance of narG, nirS, nirK, and nosZ Genes of Denitrifying Bacteria during Primary Successions of a Glacier Foreland

2006 ◽  
Vol 72 (9) ◽  
pp. 5957-5962 ◽  
Author(s):  
Ellen Kandeler ◽  
Kathrin Deiglmayr ◽  
Dagmar Tscherko ◽  
David Bru ◽  
Laurent Philippot
Keyword(s):  
16S Rrna ◽  
Primary Succession ◽  
Early Stage ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Glacier Foreland ◽  
Copy Numbers ◽  
Genes Encoding ◽  
Target Molecules ◽  
Denitrification Genes

ABSTRACT Quantitative PCR of denitrification genes encoding the nitrate, nitrite, and nitrous oxide reductases was used to study denitrifiers across a glacier foreland. Environmental samples collected at different distances from a receding glacier contained amounts of 16S rRNA target molecules ranging from 4.9 � 105 to 8.9 � 105 copies per nanogram of DNA but smaller amounts of narG, nirK, and nosZ target molecules. Thus, numbers of narG, nirK, nirS, and nosZ copies per nanogram of DNA ranged from 2.1 � 103 to 2.6 � 104, 7.4 � 102 to 1.4 � 103, 2.5 � 102 to 6.4 � 103, and 1.2 � 103 to 5.5 � 103, respectively. The densities of 16S rRNA genes per gram of soil increased with progressing soil development. The densities as well as relative abundances of different denitrification genes provide evidence that different denitrifier communities develop under primary succession: higher percentages of narG and nirS versus 16S rRNA genes were observed in the early stage of primary succession, while the percentages of nirK and nosZ genes showed no significant increase or decrease with soil age. Statistical analyses revealed that the amount of organic substances was the most important factor in the abundance of eubacteria as well as of nirK and nosZ communities, and copy numbers of these two genes were the most important drivers changing the denitrifying community along the chronosequence. This study yields an initial insight into the ecology of bacteria carrying genes for the denitrification pathway in a newly developing alpine environment.

scholarly journals Diversity of Lactic Acid Bacteria Associated with Fish and the Fish Farm Environment, Established by Amplified rRNA Gene Restriction Analysis

2007 ◽  
Vol 73 (9) ◽  
pp. 2947-2955 ◽  
Author(s):  
Christian Michel ◽  
Claire Pelletier ◽  
Mekki Boussaha ◽  
Diane-Gaëlle Douet ◽  
Armand Lautraite ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Opportunistic Infections ◽  
Restriction Analysis ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Fish Food ◽  
Group A ◽  
Gene Restriction

ABSTRACT Lactic acid bacteria have become a major source of concern for aquaculture in recent decades. In addition to true pathogenic species of worldwide significance, such as Streptococcus iniae and Lactococcus garvieae, several species have been reported to produce occasional fish mortalities in limited geographic areas, and many unidentifiable or ill-defined isolates are regularly isolated from fish or fish products. To clarify the nature and prevalence of different fish-associated bacteria belonging to the lactic acid bacterium group, a collection of 57 isolates of different origins was studied and compared with a set of 22 type strains, using amplified rRNA gene restriction analysis (ARDRA). Twelve distinct clusters were delineated on the basis of ARDRA profiles and were confirmed by sequencing of sodA and 16S rRNA genes. These clusters included the following: Lactococcus raffinolactis, L. garvieae, Lactococcus l., S. iniae, S. dysgalactiae, S. parauberis, S. agalactiae, Carnobacterium spp., the Enterococcus “faecium” group, a heterogeneous Enterococcus-like cluster comprising indiscernible representatives of Vagococcus fluvialis or the recently recognized V. carniphilus, V. salmoninarum, and Aerococcus spp. Interestingly, the L. lactis and L. raffinolactis clusters appeared to include many commensals of fish, so opportunistic infections caused by these species cannot be disregarded. The significance for fish populations and fish food processing of three or four genetic clusters of uncertain or complex definition, namely, Aerococcus and Enterococcus clusters, should be established more accurately.

Characterization of the microbial diversity in a biotreatment process using non-culture based methods

2000 ◽  
Vol 42 (3-4) ◽  
pp. 143-148 ◽  
Author(s):  
S.J. You ◽  
C.F. Ouyang ◽  
S.F. Lin ◽  
W.T. Liu
Keyword(s):  
Activated Sludge ◽  
Microbial Population ◽  
Molecular Techniques ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Biological Nutrient Removal ◽  
Growth State ◽  
Microbial Structures ◽  
Population Structures

Molecular techniques were used to compare the microbial community of suspended activated sludge and attached biofilm in a biological nutrient removal process (TNCU-I) operated under various COD/total P (COD/TP) feed ratios. Analysis of restriction fragment length polymorphism of amplified 16S rRNA genes indicated that the microbial population structures were more closely related among those sludge samples taken from aerobic sludge than that taken from biofilm attached on the RBC. The use of different COD/TP feed ratios (300/2.5-300/25) had no significant effect on the change of microbial structures of sludge samples. The 16S rDNA clone library further indicated that at least eight and six different microbial populations were present in activated sludge and RBC biofilm, respectively. The phylogenetic analysis revealed that six of those eight major clones obtained from the suspended activated sludge were from the beta-subclass of the class Proteobacteria. In contrast, only one clone obtained from biofilm belonged to the beta-subclass of the Proteobacteria. This difference in the microbial population structure was possibly attributed to the growth state (suspended or attached) or carbon source (autographs or heterotrophs) of the sludge samples rather than the effect of the COD/TP ratio used.

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