scholarly journals Distinct Bacterial Communities Exist beneath a High Arctic Polythermal Glacier

2006 ◽  
Vol 72 (9) ◽  
pp. 5838-5845 ◽  
Author(s):  
Maya Bhatia ◽  
Martin Sharp ◽  
Julia Foght
Keyword(s):  
Bacterial Communities ◽  
Drainage System ◽  
High Arctic ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Polymorphism Analysis ◽  
Basal Ice ◽  
Seasonal Flow ◽  
Glacial Environments ◽  
Polythermal Glacier

ABSTRACT Bacterial communities reside in basal ice, sediment, and meltwater in the supra-, sub-, and proglacial environments of John Evans Glacier, Nunavut, Canada. We examined whether the subglacial bacterial community shares common members with the pro- and supraglacial communities, and by inference, whether it could be derived from communities in either of these environments (e.g., by ice overriding proglacial sediments or by in-wash of surface meltwaters). Terminal restriction fragment length polymorphism analysis of bacterial 16S rRNA genes amplified from these environments revealed that the subglacial water, basal ice, and sediment communities were distinct from those detected in supraglacial meltwater and proglacial sediments, with 60 of 142 unique terminal restriction fragments (T-RFs) detected exclusively in subglacial samples and only 8 T-RFs detected in all three environments. Supraglacial waters shared some T-RFs with subglacial water and ice, likely reflecting the seasonal flow of surface meltwater into the subglacial drainage system, whereas supraglacial and proglacial communities shared the fewest T-RFs. Thus, the subglacial community at John Evans Glacier appears to be predominantly autochthonous rather than allochthonous, and it may be adapted to subglacial conditions. Chemical analysis of water and melted ice also revealed differences between the supraglacial and proglacial environments, particularly regarding electrical conductivity and nitrate, sulfate, and dissolved organic carbon concentrations. Whereas the potential exists for common bacterial types to be broadly distributed throughout the glacial system, we have observed distinct bacterial communities in physically and chemically different glacial environments.

scholarly journals The Effect of a Sublethal Temperature Elevation on the Structure of Bacterial Communities Associated with the CoralPorites compressa

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Jennifer L. Salerno ◽  
Dan R. Reineman ◽  
Ruth D. Gates ◽  
Michael S. Rappé
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Polymorphism Analysis ◽  
Significant Shift ◽  
Coral Host ◽  
Experimental Conditions

Evidence points to a link between environmental stressors, coral-associated bacteria, and coral disease; however, few studies have examined the details of this relationship under tightly controlled experimental conditions. To address this gap, an array of closed-system, precision-controlled experimental aquaria were used to investigate the effects of an abrupt 1°C above summer ambient temperature increase on the bacterial community structure and photophysiology ofPorites compressacorals. While the temperature treatment rapidly impacted the photophysiology of the coral host, it did not elicit a statistically significant shift in bacterial community structure from control, untreated corals as determined by terminal restriction fragment length polymorphism analysis of 16S rRNA genes. Two of three coral colonies harbored more closely related bacterial communities at the time of collection and, despite statistically significant shifts in bacterial community structure for both control and treatment corals during the 10-day acclimation period, maintained this relationship over the course of the experiment. The experimental design used in this study proved to be a robust, reproducible system for investigating coral microbiology in an aquarium setting.

scholarly journals Diversity and Dynamics of Seaweed Associated Microbial Communities Inhabiting the Lagoon of Venice

2020 ◽  
Vol 8 (11) ◽  
pp. 1657
Author(s):  
Abdul-Salam Juhmani ◽  
Alessandro Vezzi ◽  
Mohammad Wahsha ◽  
Alessandro Buosi ◽  
Fabio De Pascale ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Bacterial Communities ◽  
Host Response ◽  
Environmental Parameters ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Nutrient Concentrations ◽  
Lagoon Of Venice ◽  
Anthropogenic Stressors ◽  
Rich Diversity

Seaweeds are a group of essential photosynthetic organisms that harbor a rich diversity of associated microbial communities with substantial functions related to host health and defense. Environmental and anthropogenic stressors may disrupt the microbial communities and their metabolic activity, leading to host physiological alterations that negatively affect seaweeds’ performance and survival. Here, the bacterial communities associated with one of the most common seaweed, Ulva laetevirens Areshough, were sampled over a year at three sites of the lagoon of Venice affected by different environmental and anthropogenic stressors. Bacterial communities were characterized through Illumina sequencing of the V4 hypervariable region of 16S rRNA genes. The study demonstrated that the seaweed associated bacterial communities at sites impacted by environmental stressors were host-specific and differed significantly from the less affected site. Furthermore, these communities were significantly distinct from those of the surrounding seawater. The bacterial communities’ composition was significantly correlated with environmental parameters (nutrient concentrations, dissolved oxygen saturation, and pH) across sites. This study showed that several more abundant bacteria on U. laetevirens at stressed sites belonged to taxa related to the host response to the stressors. Overall, environmental parameters and anthropogenic stressors were shown to substantially affect seaweed associated bacterial communities, which reflect the host response to environmental variations.

scholarly journals Variability of the Sheep Lung Microbiota

2016 ◽  
Vol 82 (11) ◽  
pp. 3225-3238 ◽  
Author(s):  
Laura Glendinning ◽  
Steven Wright ◽  
Jolinda Pollock ◽  
Peter Tennant ◽  
David Collie ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Dna Sequences ◽  
Bacterial Communities ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Large Animal ◽  
Local Factors ◽  
Adult Sheep ◽  
Sequencing Technologies ◽  
Host Influence

ABSTRACTSequencing technologies have recently facilitated the characterization of bacterial communities present in lungs during health and disease. However, there is currently a dearth of information concerning the variability of such data in health both between and within subjects. This study seeks to examine such variability using healthy adult sheep as our model system. Protected specimen brush samples were collected from three spatially disparate segmental bronchi of six adult sheep (age, 20 months) on three occasions (day 0, 1 month, and 3 months). To further explore the spatial variability of the microbiotas, more-extensive brushing samples (n= 16) and a throat swab were taken from a separate sheep. The V2 and V3 hypervariable regions of the bacterial 16S rRNA genes were amplified and sequenced via Illumina MiSeq. DNA sequences were analyzed using the mothur software package. Quantitative PCR was performed to quantify total bacterial DNA. Some sheep lungs contained dramatically different bacterial communities at different sampling sites, whereas in others, airway microbiotas appeared similar across the lung. In our spatial variability study, we observed clustering related to the depth within the lung from which samples were taken. Lung depth refers to increasing distance from the glottis, progressing in a caudal direction. We conclude that both host influence and local factors have impacts on the composition of the sheep lung microbiota.IMPORTANCEUntil recently, it was assumed that the lungs were a sterile environment which was colonized by microbes only during disease. However, recent studies using sequencing technologies have found that there is a small population of bacteria which exists in the lung during health, referred to as the “lung microbiota.” In this study, we characterize the variability of the lung microbiotas of healthy sheep. Sheep not only are economically important animals but also are often used as large animal models of human respiratory disease. We conclude that, while host influence does play a role in dictating the types of microbes which colonize the airways, it is clear that local factors also play an important role in this regard. Understanding the nature and influence of these factors will be key to understanding the variability in, and functional relevance of, the lung microbiota.

scholarly journals Intra-annual and intra-seasonal flow dynamics of a High Arctic polythermal valley glacier

2003 ◽  
Vol 37 ◽  
pp. 181-188 ◽  
Author(s):  
Robert G. Bingham ◽  
Peter W. Nienow ◽  
Martin J. Sharp
Keyword(s):  
Drainage System ◽  
High Arctic ◽  
Ablation Zone ◽  
Accumulation Zone ◽  
Seasonal Flow ◽  
Excess Surface ◽  
Velocity Response ◽  
Spatio Temporal ◽  
June July ◽  
Arctic Glacier

AbstractMeasurements of surface dynamics on polythermal John Evans Glacier, Nunavut, Canada, over two winter periods and every 7–10 days throughout two melt seasons (June–July 2000, 2001) provide new insight into spatio-temporal patterns of High Arctic glacier dynamics. In the lower ablation zone, mean annual surface velocities are 10–21 m a–1, but peak velocities up to 50% higher are attained during late June/early July. In the upper ablation zone and lower accumulation zone, mean annual surface velocities are typically 10–18 m a–1, and peak velocities up to 40% higher occur during late July. In the upper accumulation zone, mean annual surface velocities are 2–9 m a–1, and motion in mid- to late July exceeds this by up to 10%. Rapid drainage of ponded supraglacial water in the upper ablation zone to an initially distributed subglacial drainage system in mid-June may force excess surface motion in the warm-based lower glacier. The data indicate that the duration of the velocity response may be related to the rate of channelization of the basal drainage, and the velocity response may be transmitted up-glacier by longitudinal coupling. An increase in surface velocities in the middle glacier in late July occurs in conjunction with the opening of two further moulins in the accumulation zone.

scholarly journals Unraveling the Etiology of North American Grapevine Yellows (NAGY): Novel NAGY Phytoplasma Sequevars Related to ‘Candidatus Phytoplasma pruni’

Plant Disease ◽  
2015 ◽  
Vol 99 (8) ◽  
pp. 1087-1097 ◽  
Author(s):  
Robert E. Davis ◽  
Ellen L. Dally ◽  
Yan Zhao ◽  
Ing-Ming Lee ◽  
Wei Wei ◽  
...  
Keyword(s):  
16S Rdna ◽  
North American ◽  
Phylogenetic Analyses ◽  
New York State ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Vitis Vinifera L ◽  
Polymorphism Analysis ◽  
Ribosomal Protein Genes ◽  
Grapevine Yellows

North American grapevine yellows (NAGY) disease has sometimes been attributed to infection of Vitis vinifera L. by Prunus X-disease phytoplasma (‘Candidatus Phytoplasma pruni’) but this attribution may not be fully adequate. In this study, phytoplasma strains related to ‘Ca. Phytoplasma pruni’ were found in NAGY-diseased grapevines in Maryland, Pennsylvania, Virginia, Ohio, Missouri, and New York State. Based on restriction fragment length polymorphism analysis of 16S ribosomal RNA gene (16S rDNA) sequences, the strains (termed NAGYIII strains) were classified in group 16SrIII (X-disease group) but they contained a recognition site for the restriction endonuclease MseI that is not present in the 16S rDNA of ‘Ca. Phytoplasma pruni’. The 16S rDNA of the strains differed by three or four nucleotides from that of ‘Ca. Phytoplasma pruni’, indicating that they belonged to two novel 16S rDNA sequevars, designated NAGYIIIα and NAGYIIIβ. Both sequevars differed from ‘Ca. Phytoplasma pruni’ by a single base in each of three regions corresponding to species-unique (signature) sequences described for ‘Ca. Phytoplasma pruni’. Phylogenetic analyses of 16S rRNA genes and SecY proteins, and single-nucleotide polymorphism analyses of secY and ribosomal protein genes, further distinguished the two grapevine sequevar lineages from one another and from ‘Ca. Phytoplasma pruni’. The NAGYIIIα and NAGYIIIβ sequevars also differed from ‘Ca. Phytoplasma pruni’ in regions of the folded SecY protein that are predicted to be near or exposed at the outer surface of the phytoplasma membrane. No evidence indicated that diseased grapevines contained any phytoplasma strain conforming to ‘Ca. Phytoplasma pruni’ sensu stricto. Because the NAGYIII sequevars have not been reported in X-disease, a question is raised as to whether NAGYIII and Prunus X-disease are caused by different phytoplasma genotypes.

Composition of the archaeal community involved in methane production during the decomposition of Microcystis blooms in the laboratory

2012 ◽  
Vol 58 (10) ◽  
pp. 1153-1158 ◽  
Author(s):  
Peng Xing ◽  
Huabing Li ◽  
Qing Liu ◽  
Jiuwen Zheng
Keyword(s):  
Lake Taihu ◽  
Archaeal Community ◽  
Oxygen Depletion ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Polymorphism Analysis ◽  
Methanogenic Community ◽  
Controlled Systems ◽  
Microcystis Blooms ◽  
Different Temperatures

We investigated the microbial processes involved in methane (CH4) production from Microcystis bloom scums at different temperatures. A Microcystis slurry was collected from Lake Taihu and incubated in airtight bottles at 15, 25, and 35 °C. The production of CH4 was monitored, and the emission rate was calculated. The dynamics of the methanogenic community were analyzed by terminal restriction fragment length polymorphism analysis of archaeal 16S rRNA genes. Phylogenetic information for the methanogens was obtained by cloning and sequencing selected samples. Significant CH4 emission from the Microcystis scums was delayed by approximately 12 days by the natural oxygen depletion process, and CH4 production was enhanced at higher temperatures. Phylogenetic analysis indicated that the archaeal community was composed of Methanomicrobiales, Methanobacteriaceae, and a novel cluster of Archaea. An apparent succession of the methanogenic community was demonstrated, with a predominance of Methanobacteriaceae at higher temperatures. Higher temperatures enhanced the methanogenic transformation of the Microcystis biomass and the phylogenetic dominance of hydrogenotrophic methanogens, suggesting that H2 and CO2 might be the primary substrates for CH4 production during Microcystis decomposition without the participation of lake sediment. This work provides insight into the microbial components involved in Microcystis biomass fermentation in controlled systems.

PCR-Ribotyping of Xenorhabdus andPhotorhabdus Isolates from the Caribbean Region in Relation to the Taxonomy and Geographic Distribution of Their Nematode Hosts

1998 ◽  
Vol 64 (11) ◽  
pp. 4246-4254 ◽  
Author(s):  
Marion Fischer-Le Saux ◽  
Hervé Mauléon ◽  
Philippe Constant ◽  
Brigitte Brunel ◽  
Noël Boemare
Keyword(s):  
Entomopathogenic Nematodes ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Caribbean Region ◽  
Polymorphism Analysis ◽  
Caribbean Islands ◽  
Pcr Ribotyping ◽  
The Caribbean ◽  
And Cluster Analysis ◽  
Reference Strains

ABSTRACT The genetic diversity of symbiotic Xenorhabdus andPhotorhabdus bacteria associated with entomopathogenic nematodes was examined by a restriction fragment length polymorphism analysis of PCR-amplified 16S rRNA genes (rDNAs). A total of 117 strains were studied, most of which were isolated from the Caribbean basin after an exhaustive soil sampling. The collection consisted of 77 isolates recovered from entomopathogenic nematodes in 14 Caribbean islands and of 40 reference strains belonging toXenorhabdus and Photorhabdus spp. collected at various localities worldwide. Thirty distinctive 16S rDNA genotypes were identified, and cluster analysis was used to distinguish the genus Xenorhabdus from the genusPhotorhabdus. The genus Xenorhabdusappears more diverse than the genusPhotorhabdus, and for both genera the bacterial genotype diversity is in congruence with the host-nematode taxonomy. The occurrence of symbiotic bacterial genotypes was related to the ecological distribution of host nematodes.

Changes in the structure and diversity of bacterial communities during the process of adaptation to organic wastewater

2010 ◽  
Vol 56 (4) ◽  
pp. 352-355 ◽  
Author(s):  
Junmin Li ◽  
Zexin Jin ◽  
Binbin Yu
Keyword(s):  
Bacterial Communities ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Similarity Index ◽  
Pcr Amplification ◽  
Genotypic Diversity ◽  
Diversity Indices ◽  
Inhibitory Effect ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Gradient Gel Electrophoresis

To explore changes in the structure and diversity of activated sludge-derived microbial communities during adaptation to gradual increases in the concentration of wastewater, RAPD–PCR and the combination of PCR amplification of 16S rRNA genes with denaturing gradient gel electrophoresis (DGGE) analysis were used. In bacterial communities exposed to 0%, 5%, 10%, 20%, or 40% wastewater, there were 27, 25, 18, 17 and 16 bands, respectively, based on DGGE data, while there were 69, 83, 97, 86, and 88 bands, respectively, based on RAPD data. The community similarity index among bacterial communities during the process of adaptation to different concentrations of wastewater was different based on DGGE and RAPD data. Based on DGGE and RAPD profiles, the Shannon–Weiner and Simpson’s diversity indices decreased sharply upon exposure to 10% wastewater, indicating that 10% wastewater might be a critical point at which the growth of bacteria could be significantly inhibited and the genotypic diversity could change. This indicated that changes in structure and diversity might have an inhibitory effect on the toxicity of organic matter and that selection and adaptation could play important roles in the changes.

Sign in / Sign up

Export Citation Format

Share Document