scholarly journals Diversity of Viruses Infecting the Green Microalga Ostreococcus lucimarinus

2015 ◽  
Vol 89 (11) ◽  
pp. 5812-5821 ◽  
Author(s):  
Evelyne Derelle ◽  
Adam Monier ◽  
Richard Cooke ◽  
Alexandra Z. Worden ◽  
Nigel H. Grimsley ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Genetic Distances ◽  
Host Strain ◽  
Phylogenetic Distance ◽  
Widespread Species ◽  
Content Type ◽  
Virus Diversity ◽  
Eukaryotic Phytoplankton ◽  
Green Microalga ◽  
Ostreococcus Lucimarinus

ABSTRACTThe functional diversity of eukaryotic viruses infecting a single host strain from seawater samples originating from distant marine locations is unknown. To estimate this diversity, we used lysis plaque assays to detect viruses that infect the widespread speciesOstreococcus lucimarinus, which is found in coastal and mesotrophic systems, andO. tauri, which was isolated from coastal and lagoon sites from the northwest Mediterranean Sea. Detection of viral lytic activities againstO. tauriwas not observed using seawater from most sites, except those close to the area where the host strain was isolated. In contrast, the more cosmopolitanO. lucimarinusspecies recovered viruses from locations in the Atlantic and Pacific Oceans and the Mediterranean Sea. Six newO. lucimarinusviruses (OlVs) then were characterized and their genomes sequenced. Two subgroups of OlVs were distinguished based on their genetic distances and on the inversion of a central 32-kb-long DNA fragment, but overall their genomes displayed a high level of synteny. The two groups did not correspond to proximity of isolation sites, and the phylogenetic distance between these subgroups was higher than the distances observed among viruses infectingO. tauri. Our study demonstrates that viruses originating from very distant sites are able to infect the same algal host strain and can be more diverse than those infecting different species of the same genus. Finally, distinctive features and evolutionary distances between these different viral subgroups does not appear to be linked to biogeography of the viral isolates.IMPORTANCEMarine eukaryotic phytoplankton virus diversity has yet to be addressed, and more specifically, it is unclear whether diversity is connected to geographical distance and whether differential infection and lysis patterns exist among such viruses that infect the same host strain. Here, we assessed the genetic distance of geographically segregated viruses that infect the ubiquitous green microalgaOstreococcus. This study provides the first glimpse into the diversity of predicted gene functions inOstreococcusviruses originating from distant sites and provides new insights into potential host distributions and restrictions in the world oceans.

scholarly journals First Description of Two Sequence Type 2 Acinetobacter baumannii Isolates Carrying OXA-23 Carbapenemase in Pagellus acarne Fished from the Mediterranean Sea near Bejaia, Algeria

2016 ◽  
Vol 60 (4) ◽  
pp. 2513-2515 ◽  
Author(s):  
Soumia Brahmi ◽  
Abdelaziz Touati ◽  
Axelle Cadière ◽  
Nassima Djahmi ◽  
Alix Pantel ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Mediterranean Sea ◽  
Sequence Type ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Selective Agar ◽  
Agar Media ◽  
The Mediterranean ◽  
First Time

ABSTRACTTo determine the occurrence of carbapenem-resistantAcinetobacter baumanniiin fish fished from the Mediterranean Sea near the Bejaia coast (Algeria), we studied 300 gills and gut samples that had been randomly and prospectively collected during 1 year. After screening on selective agar media, using PCR arrays and whole-genome sequencing, we identified for the first time two OXA-23-producingA. baumanniistrains belonging to the widespread sequence type 2 (ST2)/international clone II and harboring aminoglycoside-modifying enzymes [aac(6′)-Ib andaac(3′)-I genes].

scholarly journals Antifungal Susceptibility Patterns of Opportunistic Fungi in the Genera Verruconis and Ochroconis

2014 ◽  
Vol 58 (6) ◽  
pp. 3285-3292 ◽  
Author(s):  
S. Seyedmousavi ◽  
K. Samerpitak ◽  
A. J. M. M. Rijs ◽  
W. J. G. Melchers ◽  
J. W. Mouton ◽  
...  
Keyword(s):  
Geometric Mean ◽  
Antifungal Susceptibility ◽  
Species Level ◽  
Phylogenetic Distance ◽  
Dematiaceous Fungi ◽  
Opportunistic Fungi ◽  
Content Type ◽  
Broth Microdilution Method ◽  
Susceptibility Patterns

ABSTRACTSpecies ofVerruconisand species ofOchroconisare dematiaceous fungi generally found in the environment but having the ability to infect humans, dogs, cats, poultry, and fish. This study presents the antifungal susceptibility patterns of these fungi at the species level. Forty strains originating from clinical and environmental sources were phylogenetically identified at the species level by using sequences of the ribosomal DNA internal transcribed spacer (rDNA ITS).In vitroantifungal susceptibility testing was performed against eight antifungals, using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. The geometric mean MICs for amphotericin B (AMB), flucytosine (5FC), fluconazole (FLC), itraconazole (ITC), voriconazole (VRC), and posaconazole (POS) and minimum effective concentrations (MECs) for caspofungin (CAS) and anidulafungin (AFG) across theOchroconisandVerruconisspecies were as follows, in increasing order. ForVerruconisspecies, the values (μg/ml) were as follows: AFG, 0.04; POS, 0.25; ITC, 0.37; AMB, 0.50; CAS, 0.65; VRC, 0.96; 5FC, 10.45; and FLC, 47.25. ForOchroconisspecies, the values (μg/ml) were as follows: AFG, 0.06; POS, 0.11; CAS, 0.67; VRC, 2.76; ITC, 3.94; AMB, 5.68; 5FC, 34.48; and FLC, 61.33. Antifungal susceptibility ofOchroconisandVerruconiswas linked with phylogenetic distance and thermotolerance. Echinocandins and POS showed the greatestin vitroactivity, providing possible treatment options forOchroconisandVerruconisinfections.

Thermoanaerobacter pentosaceus sp. nov., an anaerobic, extremely thermophilic, high ethanol-yielding bacterium isolated from household waste

2013 ◽  
Vol 63 (Pt_7) ◽  
pp. 2396-2404 ◽  
Author(s):  
Ana Faria Tomás ◽  
Dimitar Karakashev ◽  
Irini Angelidaki
Keyword(s):  
Type Species ◽  
Sequence Similarity ◽  
Maximum Yield ◽  
Maximum Growth ◽  
Household Waste ◽  
Rrna Gene ◽  
Strictly Anaerobic ◽  
Phylogenetic Distance ◽  
Content Type ◽  
Link Type

An extremely thermophilic, xylanolytic, spore-forming and strictly anaerobic bacterium, strain DTU01T, was isolated from a continuously stirred tank reactor fed with xylose and household waste. Cells stained Gram-negative and were rod-shaped (0.5–2 µm in length). Spores were terminal with a diameter of approximately 0.5 µm. Optimal growth occurred at 70 °C and pH 7, with a maximum growth rate of 0.1 h−1. DNA G+C content was 34.2 mol%. Strain DTU01T could ferment arabinose, cellobiose, fructose, galactose, glucose, lactose, mannitol, mannose, melibiose, pectin, starch, sucrose, xylan, yeast extract and xylose, but not cellulose, Avicel, inositol, inulin, glycerol, rhamnose, acetate, lactate, ethanol, butanol or peptone. Ethanol was the major fermentation product and a maximum yield of 1.39 mol ethanol per mol xylose was achieved when sulfite was added to the cultivation medium. Thiosulfate, but not sulfate, nitrate or nitrite, could be used as electron acceptor. On the basis of 16S rRNA gene sequence similarity, strain DTU01T was shown to be closely related to Thermoanaerobacter mathranii A3T, Thermoanaerobacter italicus Ab9T and Thermoanaerobacter thermocopriae JT3-3T, with 98–99 % similarity. Despite this, the physiological and phylogenetic differences (DNA G+C content, substrate utilization, electron acceptors, phylogenetic distance and isolation site) allow for the proposal of strain DTU01T as a representative of a novel species within the genus Thermoanaerobacter , for which the name Thermoanaerobacter pentosaceus sp. nov. is proposed, with the type strain DTU01T ( = DSM 25963T = KCTC 4529T = VKM B-2752T = CECT 8142T).

scholarly journals Climatic Refugia and Geographical Isolation Contribute to the Speciation and Genetic Divergence in Himalayan-Hengduan Tree Peonies (Paeonia delavayi and Paeonia ludlowii)

2021 ◽  
Vol 11 ◽  
Author(s):  
Yu-Juan Zhao ◽  
Gen-Shen Yin ◽  
Yue-Zhi Pan ◽  
Bo Tian ◽  
Xun Gong
Keyword(s):  
Genetic Variation ◽  
Late Quaternary ◽  
Demographic History ◽  
Nuclear Gene ◽  
Genetic Distances ◽  
Population Divergence ◽  
Widespread Species ◽  
Isolation With Migration ◽  
Isolation By Environment ◽  
Paeonia Delavayi

Himalaya and Hengduan Mountains (HHM) is a biodiversity hotspot, and very rich in endemic species. Previous phylogeographical studies proposed different hypotheses (vicariance and climate-driven speciation) in explaining diversification and the observed pattern of extant biodiversity, but it is likely that taxa are forming in this area in species-specific ways. Here, we reexplored the phylogenetic relationship and tested the corresponding hypotheses within Paeonia subsect. Delavayanae composed of one widespread species (Paeonia delavayi) and the other geographically confined species (Paeonia ludlowii). We gathered genetic variation data at three chloroplast DNA fragments and one nuclear gene from 335 individuals of 34 populations sampled from HHM. We performed a combination of population genetic summary statistics, isolation-with-migration divergence models, isolation by environment, and demographic history analyses. We found evidence for the current taxonomic treatment that P. ludlowii and P. delavayi are two different species with significant genetic differentiation. The significant isolation by environment was revealed within all sampled populations but genetic distances only explained by geographical distances within P. delavayi populations. The results of population divergence models and demographic history analyses indicated a progenitor–derivative relationship and the Late Quaternary divergence without gene flow between them. The coalescence of all sampled cpDNA haplotypes could date to the Late Miocene, and P. delavayi populations probably underwent a severe bottleneck in population size during the last glacial period. Genetic variation in Paeonia subsect. Delavayanae is associated with geographical and environmental distances. These findings point to the importance of geological and climatic changes as causes of the speciation event and lineage diversification within Paeonia subsect. Delavayanae.

scholarly journals Complete Genome Sequence of Bacillus cereus Sensu Stricto VKM B-370, Isolated from the Silkworm Bombyx mori

2021 ◽  
Vol 10 (20) ◽  
Author(s):  
Emma G. Piligrimova ◽  
Rustam M. Buzikov ◽  
Olesya A. Kazantseva ◽  
Andrey M. Shadrin
Keyword(s):  
Bacillus Cereus ◽  
Bombyx Mori ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Sensu Stricto ◽  
Host Strain ◽  
Gram Positive ◽  
Content Type ◽  
Silkworm Bombyx Mori

ABSTRACT Bacillus cereus is a Gram-positive rod-shaped spore-forming bacterium widespread in different environmental niches. Here, we report the complete genome sequence of Bacillus cereus VKM B-370 from the All-Russian Collection of Microorganisms, the host strain for bacteriophages vB_BtS_B83, vB_BcM_Sam46, vB_BcM_Sam112, and Izhevsk.

scholarly journals Deletion of the DNA Ligase IV Gene in Candida glabrata Significantly Increases Gene-Targeting Efficiency

2015 ◽  
Vol 14 (8) ◽  
pp. 783-791 ◽  
Author(s):  
Yuke Cen ◽  
Alessandro Fiori ◽  
Patrick Van Dijck
Keyword(s):  
Homologous Recombination ◽  
Gene Targeting ◽  
Candida Glabrata ◽  
The United States ◽  
Genetic Alterations ◽  
Nonhomologous End Joining ◽  
Specific Gene ◽  
Phylogenetic Distance ◽  
End Joining ◽  
Content Type

ABSTRACTCandida glabratais reported as the second most prevalent human opportunistic fungal pathogen in the United States. Over the last decades, its incidence increased, whereas that ofCandida albicansdecreased slightly. One of the main reasons for this shift is attributed to the inherent tolerance ofC. glabratatoward the commonly used azole antifungal drugs. Despite a close phylogenetic distance toSaccharomyces cerevisiae, homologous recombination works with poor efficiency inC. glabratacompared to baker's yeast, in fact limiting targeted genetic alterations of the pathogen's genome. It has been shown that nonhomologous DNA end joining is dominant over specific gene targeting inC. glabrata. To improve the homologous recombination efficiency, we have generated a strain in which theLIG4gene has been deleted, which resulted in a significant increase in correct gene targeting. The very specific function of Lig4 in mediating nonhomologous end joining is the reason for the absence of clear side effects, some of which affect theku80mutant, another mutant with reduced nonhomologous end joining. We also generated aLIG4reintegration cassette. Our results show that thelig4mutant strain may be a valuable tool for theC. glabrataresearch community.

scholarly journals Genetic Diversity and Population Divergence of a Rare, Endemic Grass (Elymus breviaristatus) in the Southeastern Qinghai-Tibetan Plateau

2019 ◽  
Vol 11 (20) ◽  
pp. 5863 ◽  
Author(s):  
Qingqing Yu ◽  
Qian Liu ◽  
Yi Xiong ◽  
Yanli Xiong ◽  
Zhixiao Dong ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Tibetan Plateau ◽  
Isolation By Distance ◽  
Genetic Distances ◽  
Conservation Strategy ◽  
Conservation Strategies ◽  
Grass Species ◽  
Population Divergence ◽  
High Genetic Diversity ◽  
Widespread Species

Elymus breviaristatus is a grass species only distributed in the southeast of Qinghai-Tibetan Plateau (QTP), which has suffered from serious habitat fragmentation. Therefore, understanding patterns of genetic diversity within and among natural E. breviaristatus populations could provide insight for future conservation strategies. In this study, sequence-related amplified polymorphism markers were employed to investigate the genetic diversity and hierarchical structure of seven E. breviaristatus populations from QTP, China. Multiple measures of genetic diversity indicated that there is low to moderate genetic variation within E. breviaristatus populations, consistent with its presumed mating system. In spite of its rarity, E. breviaristatus presented high genetic diversity that was equivalent to or even higher than that of widespread species. Bayesian clustering approaches, along with clustering analysis and principal coordinate analysis partitioned the studied populations of E. breviaristatus into five genetic clusters. Differentiation coefficients (Fst, GST, etc.) and AMOVA analysis revealed considerable genetic divergence among different populations. BARRIER analyses indicated that there were two potential barriers to gene flow among the E. breviaristatus populations. Despite these patterns of differentiation, genetic distances between populations were independent of geographic distances (r = 0.2197, p = 0.2534), indicating little isolation by distance. Moreover, despite detecting a common outlier by two methods, bioclimatic factors (altitude, annual mean temperature, and annual mean precipitation) were not related to diversity parameters, indicating little evidence for isolation caused by the environment. These patterns of diversity within and between populations are used to propose a conservation strategy for E. breviaristatus.

scholarly journals Diversity of Active Viral Infections within the Sphagnum Microbiome

2018 ◽  
Vol 84 (23) ◽  
Author(s):  
Joshua M. A. Stough ◽  
Max Kolton ◽  
Joel E. Kostka ◽  
David J. Weston ◽  
Dale A. Pelletier ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Viral Infections ◽  
Model Systems ◽  
Microbial Consortia ◽  
Soil Conditions ◽  
Marker Genes ◽  
Ecological Value ◽  
Metabolic Potential ◽  
Content Type ◽  
Virus Diversity

ABSTRACT Sphagnum-dominated peatlands play an important role in global carbon storage and represent significant sources of economic and ecological value. While recent efforts to describe microbial diversity and metabolic potential of the Sphagnum microbiome have demonstrated the importance of its microbial community, little is known about the viral constituents. We used metatranscriptomics to describe the diversity and activity of viruses infecting microbes within the Sphagnum peat bog. The vegetative portions of six Sphagnum plants were obtained from a peatland in northern Minnesota, and the total RNA was extracted and sequenced. Metatranscriptomes were assembled and contigs were screened for the presence of conserved virus marker genes. Using bacteriophage capsid protein gp23 as a marker for phage diversity, we identified 33 contigs representing undocumented phages that were active in the community at the time of sampling. Similarly, RNA-dependent RNA polymerase and the nucleocytoplasmic large DNA virus (NCLDV) major capsid protein were used as markers for single-stranded RNA (ssRNA) viruses and NCLDV, respectively. In total, 114 contigs were identified as originating from undescribed ssRNA viruses, 22 of which represent nearly complete genomes. An additional 64 contigs were identified as being from NCLDVs. Finally, 7 contigs were identified as putative virophage or polinton-like viruses. We developed co-occurrence networks with these markers in relation to the expression of potential-host housekeeping gene rpb1 to predict virus-host relationships, identifying 13 groups. Together, our approach offers new tools for the identification of virus diversity and interactions in understudied clades and suggests that viruses may play a considerable role in the ecology of the Sphagnum microbiome. IMPORTANCE Sphagnum-dominated peatlands play an important role in maintaining atmospheric carbon dioxide levels by modifying conditions in the surrounding soil to favor the growth of Sphagnum over that of other plant species. This lowers the rate of decomposition and facilitates the accumulation of fixed carbon in the form of partially decomposed biomass. The unique environment produced by Sphagnum enriches for the growth of a diverse microbial consortia that benefit from and support the moss's growth, while also maintaining the hostile soil conditions. While a growing body of research has begun to characterize the microbial groups that colonize Sphagnum, little is currently known about the ecological factors that constrain community structure and define ecosystem function. Top-down population control by viruses is almost completely undescribed. This study provides insight into the significant viral influence on the Sphagnum microbiome and identifies new potential model systems to study virus-host interactions in the peatland ecosystem.

scholarly journals Draft Genome Sequence of the Green Alga Scenedesmus acuminatus SAG 38.81

2020 ◽  
Vol 9 (24) ◽  
Author(s):  
Yekaterina Astafyeva ◽  
Malik Alawi ◽  
Daniela Indenbirken ◽  
Dominik Danso ◽  
Adam Grundhoff ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Genome Sequence ◽  
Draft Genome ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Content Type ◽  
Green Microalga ◽  
Scenedesmus Acuminatus ◽  
Valuable Compounds ◽  
Β Carotene

ABSTRACT Scenedesmus acuminatus, also known as Tetradesmus acuminatus, is a promising green microalga for sustainable production of microalga products, including valuable compounds such as astaxanthin, β-carotene, and lutein, polysaccharides such as β-glucan, and polyunsaturated fatty acids. Here, we report the draft whole-genome sequence of Scenedesmus acuminatus SAG 38.81.

scholarly journals Lysinibacillus varians sp. nov., an endospore-forming bacterium with a filament-to-rod cell cycle

2014 ◽  
Vol 64 (Pt_11) ◽  
pp. 3644-3649 ◽  
Author(s):  
Chunjie Zhu ◽  
Guoping Sun ◽  
Xingjuan Chen ◽  
Jun Guo ◽  
Meiying Xu
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Sequence Similarity ◽  
Single Cells ◽  
Rrna Gene ◽  
Phylogenetic Distance ◽  
Content Type ◽  
Dna Relatedness ◽  
Link Type

Six Gram-stain-positive, motile, filamentous and/or rod-shaped, spherical spore-forming bacteria (strains GY32T, L31, F01, F03, F06 and F07) showing polybrominated diphenyl ether transformation were investigated to determine their taxonomic status. After spore germination, these organisms could grow more than one hundred microns long as intact single cells and then divide into rod cells and form endospores in 33 h. The cell-wall peptidoglycan of these strains was type A4α, the predominant menaquinone was MK-7 and the major fatty acids were iso-C16 : 0, iso-C15 : 0 and C16 : 1ω7C. Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine were detected in the polar lipid profile. Analysis of the 16S rRNA gene sequences indicated that these strains should be placed in the genus Lysinibacillus and they were most closely related to Lysinibacillus sphaericus DSM 28T (99 % 16S rRNA gene sequence similarity). The gyrB sequence similarity and DNA–DNA relatedness between strain GY32T and L. sphaericus JCM 2502T were 81 % and 52 %, respectively. The G+C content of the genomic DNA of strain GY32T was 43.2 mol%. In addition, strain GY32T showed differences in nitrate reduction, starch and gelatin hydrolysis, carbon resource utilization and cell morphology. The phylogenetic distance from its closest relative measured by DNA–DNA relatedness and DNA G+C content, and its phenotypic properties demonstrated that strain GY32T represents a novel species of the genus Lysinibacillus , for which the name Lysinibacillus varians sp. nov. is proposed. The type strain is GY32T ( = NBRC 109424T = CGMCC 1.12212T = CCTCC M 2011307T).

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