scholarly journals PCR amplification and DNA sequence of mcyA gene: The distribution profile of a toxigenic Microcystis aeruginosa in the Hartbeespoort Dam, South Africa

2013 ◽  
Vol 11 (3) ◽  
pp. 563-572 ◽  
Author(s):  
Elbert A. Mbukwa ◽  
Sammy Boussiba ◽  
Victor Wepener ◽  
Stefan Leu ◽  
Yuval Kaye ◽  
...  
Keyword(s):  
Microcystis Aeruginosa ◽  
Water Samples ◽  
Gene Sequence ◽  
Sequence Data ◽  
Pcr Amplification ◽  
Free Water ◽  
Extracellular Dna ◽  
Distribution Profile ◽  
Sequence Segment ◽  
Mcy Genes

Using new polymerase chain reaction (PCR) primers, a once known to be under-transcribed microcystin synthetase A (mcyA) gene from the only known toxigenic cyanobacterium Microcystis aeruginosa dominating the Hartbeespoort Dam was consistently amplified from genomic DNA extracted from a set of algal and cell free water samples collected across this dam. In addition to this, five more mcy genes (mcyBCDEG) were also amplified during this study. The resultant mcyA PCR products (518 bp) were purified and sequenced and gave nucleotide sequence segments of 408 bp sizes. The obtained sequence was aligned to the published mcyA gene sequence available online on the NCBI database and resulted in 100% similarity to a 408 bp mcyA gene sequence segment of M. aeruginosa UWOCC RID-1. Furthermore, it was found that the above sequence segment (408 bp) spans from a common base in M. aeruginosa PCC 7806 and M. aeruginosa PCC 7820 from 141 to 548 bp in the N-methyl transferase (NMT) region signifying their closer relatedness to M. aeruginosa UWOCC strains. This study has for the first time amplified mcyA gene consistently from both intracellular and extracellular DNA extracts obtained from algal and cell free water samples, respectively. Sequence data and the amplified mcy genes showed that M. aeruginosa is widely distributed and dominant in this dam.

scholarly journals Numerous uncharacterized and highly divergent microbes which colonize humans are revealed by circulating cell-free DNA

2017 ◽  
Vol 114 (36) ◽  
pp. 9623-9628 ◽  
Author(s):  
Mark Kowarsky ◽  
Joan Camunas-Soler ◽  
Michael Kertesz ◽  
Iwijn De Vlaminck ◽  
Winston Koh ◽  
...  
Keyword(s):  
Human Body ◽  
Sequence Data ◽  
Human Microbiome ◽  
Pcr Amplification ◽  
The Body ◽  
Direct Pcr ◽  
Cell Free Dna ◽  
Free Dna ◽  
Novel Taxa ◽  
Circulating Cell Free Dna

Blood circulates throughout the human body and contains molecules drawn from virtually every tissue, including the microbes and viruses which colonize the body. Through massive shotgun sequencing of circulating cell-free DNA from the blood, we identified hundreds of new bacteria and viruses which represent previously unidentified members of the human microbiome. Analyzing cumulative sequence data from 1,351 blood samples collected from 188 patients enabled us to assemble 7,190 contiguous regions (contigs) larger than 1 kbp, of which 3,761 are novel with little or no sequence homology in any existing databases. The vast majority of these novel contigs possess coding sequences, and we have validated their existence both by finding their presence in independent experiments and by performing direct PCR amplification. When their nearest neighbors are located in the tree of life, many of the organisms represent entirely novel taxa, showing that microbial diversity within the human body is substantially broader than previously appreciated.

scholarly journals Occurrence of Toxic Cyanobacterial Blooms in Rio de la Plata Estuary, Argentina: Field Study and Data Analysis

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
L. Giannuzzi ◽  
G. Carvajal ◽  
M. G. Corradini ◽  
C. Araujo Andrade ◽  
R. Echenique ◽  
...  
Keyword(s):  
Microcystis Aeruginosa ◽  
Water Samples ◽  
Probabilistic Models ◽  
Cyanobacterial Blooms ◽  
Fecal Coliforms ◽  
Rio De La Plata ◽  
Domestic Water ◽  
Río De La Plata ◽  
Total Coliforms ◽  
La Plata

Water samples were collected during 3 years (2004–2007) at three sampling sites in the Rio de la Plata estuary. Thirteen biological, physical, and chemical parameters were determined on the water samples. The presence of microcystin-LR in the reservoir samples, and also in domestic water samples, was confirmed and quantified. Microcystin-LR concentration ranged between 0.02 and 8.6 μg.L−1. Principal components analysis was used to identify the factors promoting cyanobacteria growth. The proliferation of cyanobacteria was accompanied by the presence of high total and fecal coliforms bacteria (>1500 MNP/100 mL), temperature ≥25∘C, and total phosphorus content ≥1.24 mg·L−1. The observed fluctuating patterns ofMicrocystis aeruginosa, total coliforms, and Microcystin-LR were also described by probabilistic models based on the log-normal and extreme value distributions. The sampling sites were compared in terms of the distribution parameters and the probability of observing high concentrations forMicrocystis aeruginosa, total coliforms, and microcystin-LR concentration.

scholarly journals Taxonomy of Australian clinical isolates of the genus Photorhabdus and proposal of Photorhabdus asymbiotica subsp. asymbiotica subsp. nov. and P. asymbiotica subsp. australis subsp. nov.

2004 ◽  
Vol 54 (4) ◽  
pp. 1301-1310 ◽  
Author(s):  
R. J. Akhurst ◽  
N. E. Boemare ◽  
P. H. Janssen ◽  
M. M. Peel ◽  
D. A. Alfredson ◽  
...  
Keyword(s):  
16S Rrna ◽  
Dna Hybridization ◽  
Gene Sequence ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Clinical Isolates ◽  
Rrna Gene ◽  
Clinical Specimens ◽  
The Usa ◽  
Gene Sequence Data

The relationship of Photorhabdus isolates that were cultured from human clinical specimens in Australia to Photorhabdus asymbiotica isolates from human clinical specimens in the USA and to species of the genus Photorhabdus that are associated symbiotically with entomopathogenic nematodes was evaluated. A polyphasic approach that involved DNA–DNA hybridization, phylogenetic analyses of 16S rRNA and gyrB gene sequences and phenotypic characterization was adopted. These investigations showed that gyrB gene sequence data correlated well with DNA–DNA hybridization and phenotypic data, but that 16S rRNA gene sequence data were not suitable for defining species within the genus Photorhabdus. Australian clinical isolates proved to be related most closely to clinical isolates from the USA, but the two groups were distinct. A novel subspecies, Photorhabdus asymbiotica subsp. australis subsp. nov. (type strain, 9802892T=CIP 108025T=ACM 5210T), is proposed, with the concomitant creation of Photorhabdus asymbiotica subsp. asymbiotica subsp. nov. Analysis of gyrB sequences, coupled with previously published data on DNA–DNA hybridization and PCR-RFLP analysis of the 16S rRNA gene, indicated that there are more than the three subspecies of Photorhabdus luminescens that have been described and confirmed the validity of the previously proposed subdivision of Photorhabdus temperata. Although a non-luminescent, symbiotic isolate clustered consistently with P. asymbiotica in gyrB phylogenetic analyses, DNA–DNA hybridization indicated that this isolate does not belong to the species P. asymbiotica and that there is a clear distinction between symbiotic and clinical species of Photorhabdus.

scholarly journals Molecular phylogeny of the heterocystous cyanobacteria (subsections IV and V) based on nifD

2004 ◽  
Vol 54 (2) ◽  
pp. 493-497 ◽  
Author(s):  
Brian J. Henson ◽  
Sharon M. Hesselbrock ◽  
Linda E. Watson ◽  
Susan R. Barnum
Keyword(s):  
Phylogenetic Analysis ◽  
Gene Sequence ◽  
Sequence Data ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Cellular Division ◽  
Heterocystous Cyanobacteria ◽  
Nitrogen Fixation Gene ◽  
True Branching ◽  
Gene Sequence Data

The heterocystous cyanobacteria are currently placed in subsections IV and V, which are distinguished by cellular division in one plane (false branching) and in more than one plane (true branching), respectively. Published phylogenies of 16S rRNA gene sequence data support the monophyly of the heterocystous cyanobacteria, with members of subsection V embedded within subsection IV. It has been postulated that members of subsection V arose from within subsection IV. Therefore, phylogenetic analysis of nucleotide sequences of the nitrogen-fixation gene nifD from representatives of subsections IV and V was performed by using maximum-likelihood criteria. The heterocystous cyanobacteria are supported as being monophyletic, with the non-heterocystous cyanobacteria as their closest relative. However, neither subsection IV nor subsection V is monophyletic, with representatives of both subsections intermixed in two sister clades. Analysis of nifD does not support recognition of two distinct subsections.

scholarly journals Morphology, morphogenesis and molecular phylogeny of an oxytrichid ciliate, Rubrioxytricha haematoplasma (Blatterer & Foissner, 1990) Berger, 1999 (Ciliophora, Hypotricha)

2015 ◽  
Vol 65 (Pt_1) ◽  
pp. 309-320 ◽  
Author(s):  
Wenping Chen ◽  
Xumiao Chen ◽  
Lifang Li ◽  
Alan Warren ◽  
Xiaofeng Lin
Keyword(s):  
Gene Sequence ◽  
Staining Method ◽  
Sequence Data ◽  
Small Subunit ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Small Subunit Rrna ◽  
Small Subunit Rrna Gene ◽  
Single Mass ◽  
The Right

The morphology and morphogenesis of an oxytrichid ciliate, Rubrioxytricha haematoplasma (Blatterer & Foissner, 1990) Berger, 1999, collected from brackish and marine waters in China, were investigated using live observation and the protargol staining method. The main features of the morphogenetic process are: (i) the parental adoral zone of membranelles is retained completely in the proter and the anlage of undulating membranes originates from dedifferentiation of the old structures; (ii) three frontal, four frontoventral, one buccal, five ventral and five transverse cirri are derived from the anlagen of the undulating membranes and the five streaks of frontal-ventral-transverse anlagen in the pattern of 1 : 3 : 3 : 3 : 4 : 4 from left to right; (iii) the morphogenesis of the dorsal kineties is simpler than the Oxytricha pattern, i.e. without fragmentation of the dorsal kinety 3 anlagen; (iv) the single caudal cirrus originates from the dorsal kinety 3 anlage on the right side; (v) the two macronuclear nodules fuse into a single mass during the mid-stage of morphogenesis. These features correspond well with Rubrioxytricha indica, indicating that the morphogenetic pattern of Rubrioxytricha is stable. Phylogenetic analysis based on small-subunit rRNA gene sequence data supports the monophyly of the genus Rubrioxytricha, which is nested within the non-Stylonychinae clade.

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