Skip header and navigation

Refine By

   MORE

45 records – page 1 of 5.

[Activity and structure of the sulfate-reducing bacterial community in the sediments of the southern part of Lake Baikal].

https://arctichealth.org/en/permalink/ahliterature259583
Source
Mikrobiologiia. 2014 Mar-Apr;83(2):180-90
Publication Type
Article
Author
N V Pimenov
E E Zakharova
A L Briukhanov
V A Korneeva
B B Kuznetsov
T P Turova
T V Pogodaeva
G V Kalmychkov
T I Zemskaia
Source
Mikrobiologiia. 2014 Mar-Apr;83(2):180-90
Language
Russian
Publication Type
Article
Keywords
DNA, Bacterial - genetics
Geologic Sediments - microbiology
Lakes - microbiology
Microbial Consortia - physiology
Molecular Sequence Data
Phylogeny
RNA, Ribosomal, 16S
Siberia
Sulfur-Reducing Bacteria - genetics - isolation & purification
Water Microbiology
Abstract
The rates of sulfate reduction (SR) and the diversity of sulfate-reducing bacteria (SRB) were studied in the sediments of the Posol'skaya banka elevation in the southern part of Lake Baikal. SR rates varied from 1.2 to 1641 nmol/(dm3 day), with high rates (> 600 nmol/(dm3 day)) observed at both deep-water stations and in subsurface silts. Integral SR rates calculated for the uppermost 50 cm of the sediments were higher for gas-saturated and gas hydrate-bearing sediments than in those with low methane content. Enrichment SRB cultures were obtained in Widdel medium for freshwater SRB. Analysis of the 16S rRNA gene fragments from clone libraries obtained from the enrichments revealed the presence of SRB belonged to Desulfosporosinus genus, with D. lacus as the most closely related member (capable of sulfate, sulfite, and thiosulfate reduction), as well as members of the order Clostridiales.
PubMed ID
25423722 View in PubMed
Less detail

Aeromonas aquatica sp. nov., Aeromonas finlandiensis sp. nov. and Aeromonas lacus sp. nov. isolated from Finnish waters associated with cyanobacterial blooms.

https://arctichealth.org/en/permalink/ahliterature269272
Source
Syst Appl Microbiol. 2015 May;38(3):161-8
Publication Type
Article
Date
May-2015
Author
R. Beaz-Hidalgo
F. Latif-Eugenín
M J Hossain
K. Berg
R M Niemi
J. Rapala
C. Lyra
M R Liles
M J Figueras
Source
Syst Appl Microbiol. 2015 May;38(3):161-8
Date
May-2015
Language
English
Publication Type
Article
Keywords
Aeromonas - classification - isolation & purification
Cluster analysis
DNA, Ribosomal - chemistry - genetics
DNA-Directed RNA Polymerases
Finland
Genes, Bacterial - genetics
Lakes - microbiology
Molecular Sequence Data
Multilocus Sequence Typing
Phylogeny
RNA, Ribosomal, 16S - genetics
Abstract
Three groups of Aeromonas strains isolated from Finland lakes experiencing cyanobacterial blooms could not be assigned to any known species of this genus on the basis of 16S rRNA and rpoD gene sequences. The Multilocus Phylogenetic Analysis (MLPA) of the concatenated sequence of seven genes (gyrB, rpoD, recA, dnaJ, gyrA, dnaX and atpD; 4093bp) showed that the three groups of strains did not cluster with any known Aeromonas spp. and formed three independent lineages. This was confirmed by performing the analysis with their closest relatives using 15 genes (the latter 7 and cpn60, dnaK, gltA, mdh, radA, rpoB, tsf, zipA; 8751bp). Furthermore, ANI results between the genomes of the type strains of the three potential new species and those of their close relatives were all
PubMed ID
25852023 View in PubMed
Less detail

Agroenvironmental determinants associated with the presence of antimicrobial-resistant Escherichia coli in beach waters in Quebec, Canada.

https://arctichealth.org/en/permalink/ahliterature132370
Source
Zoonoses Public Health. 2011 Sep;58(6):432-9
Publication Type
Article
Date
Sep-2011
Author
P. Turgeon
P. Michel
P. Levallois
P. Chevalier
D. Daignault
B. Crago
R. Irwin
S A McEwen
N F Neumann
M. Louie
Author Affiliation
Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada. patricia.turgeon@umontreal.ca
Source
Zoonoses Public Health. 2011 Sep;58(6):432-9
Date
Sep-2011
Language
English
Publication Type
Article
Keywords
Agriculture
Animals
Bathing Beaches
Escherichia coli - isolation & purification
Human Activities
Humans
Lakes - microbiology
Logistic Models
Quebec
Seasons
Time Factors
Water Microbiology
Abstract
Exposure to microorganisms resistant to antimicrobials may constitute a health risk to human populations. It is believed that one route of exposure occurs when people engage in recreational activities in water contaminated with these microorganisms. The main objective of this study was to explore population-level and environmental determinants specifically associated with the presence of antimicrobial resistant (AMR) generic Escherichia coli isolated from recreational waters sampled from beaches located in southern Quebec, Canada. Water samples originated from the Quebec provincial beach surveillance program for the summers of 2004 and 2005. This study focused on three classes of determinants, namely: agricultural, population-level and beach characteristics for a total of 19 specific factors. The study was designed as a retrospective observational analysis and factors were assessed using logistic regression methods. From the multivariable analysis, the data suggested that the percentage of land used for spreading liquid manure was a significant factor associated with the presence of AMR E. coli (OR=27.73). Conceptually, broad factors potentially influencing the presence of AMR bacteria in water must be assessed specifically in addition to factors associated with general microbial contamination. Presence of AMR E. coli in recreational waters from beaches in southern Quebec may represent a risk for people engaging in water activities and this study provides preliminary evidence that agricultural practices, specifically spreading liquid manure in agricultural lands nearby beaches, may be linked to the contamination of these waters by AMR E. coli.
PubMed ID
21824340 View in PubMed
Less detail

Alkaliphilus namsaraevii sp. nov., an alkaliphilic iron- and sulfur-reducing bacterium isolated from a steppe soda lake.

https://arctichealth.org/en/permalink/ahliterature285198
Source
Int J Syst Evol Microbiol. 2017 Jun;67(6):1990-1995
Publication Type
Article
Date
Jun-2017
Author
Anastasiya Zakharyuk
Lyudmila Kozyreva
Elena Ariskina
Olga Troshina
Dmitry Kopitsyn
Viktoria Shcherbakova
Source
Int J Syst Evol Microbiol. 2017 Jun;67(6):1990-1995
Date
Jun-2017
Language
English
Publication Type
Article
Keywords
Alkalies
Bacterial Typing Techniques
Base Composition
Clostridiales - classification - genetics - isolation & purification
DNA, Bacterial - genetics
Fatty Acids - chemistry
Ferric Compounds - metabolism
Lakes - microbiology
Phylogeny
RNA, Ribosomal, 16S - genetics
Russia
Sequence Analysis, DNA
Sulfur
Sulfur-Reducing Bacteria - classification - genetics - isolation & purification
Abstract
A novel alkaliphilic spore-forming bacterium was isolated from the benthic sediments of the highly mineralized steppe Lake Khilganta (Transbaikal Region, Russia). Cells of the strain, designated ?-07-2T, were straight to slightly curved rods, Gram-stain-positive and motile. Strain ?-07-2T grew in the pH range from 7.0 to 10.7 (optimum pH 9.6-10.3). Growth was observed at 25-47?°C (optimum 30?°C) and at an NaCl concentration from 5 to 150?g l-1 with an optimum at 40?g l-1. Strain ?-07-2T was a chemo-organoheterotroph able to reduce amorphous ferric hydroxide, Fe(III) citrate and elemental sulfur in the presence of yeast extract as the electron donor. It used tryptone, peptone and trypticase with Fe(III) citrate as the electron acceptor. The predominant fatty acids in cell walls were C16:1?8, iso-C15:0, C14?:?0 3-OH and C16?:?0. The DNA G+C content was 32.6?mol%. 16S rRNA gene sequence analysis revealed that strain ?-07-2T was related most closely to members of the genus Alkaliphilus within the family Clostridiaceae. The closest relative was Alkaliphilus peptidifermentans Z-7036T (96.4?% similarity). On the basis of the genotypic, chemotaxonomic and phenotypic data, strain ?-07-2T represents a novel species in the genus Alkaliphilus, for which the name Alkaliphilus namsaraevii sp. nov. is proposed. The type strain is ?-07-2T (=VKM ?-2746?=DSM 26418?).
PubMed ID
28632119 View in PubMed
Less detail

Anaerobic oxidation of methane by aerobic methanotrophs in sub-Arctic lake sediments.

https://arctichealth.org/en/permalink/ahliterature294342
Source
Sci Total Environ. 2017 Dec 31; 607-608:23-31
Publication Type
Journal Article
Date
Dec-31-2017
Author
Karla Martinez-Cruz
Mary-Cathrine Leewis
Ian Charold Herriott
Armando Sepulveda-Jauregui
Katey Walter Anthony
Frederic Thalasso
Mary Beth Leigh
Author Affiliation
Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, 306 Tanana Loop, 99775 Fairbanks, AK, USA; Biotechnology and Bioengineering Department, Cinvestav, 2508 IPN Av, 07360, Mexico City, Mexico. Electronic address: karla.martinez@umag.cl.
Source
Sci Total Environ. 2017 Dec 31; 607-608:23-31
Date
Dec-31-2017
Language
English
Publication Type
Journal Article
Keywords
Anaerobiosis
Archaea - metabolism
Arctic Regions
Geologic Sediments - microbiology
Lakes - microbiology
Methane - metabolism
Oxidation-Reduction
Abstract
Anaerobic oxidation of methane (AOM) is a biological process that plays an important role in reducing the CH4 emissions from a wide range of ecosystems. Arctic and sub-Arctic lakes are recognized as significant contributors to global methane (CH4) emission, since CH4 production is increasing as permafrost thaws and provides fuels for methanogenesis. Methanotrophy, including AOM, is critical to reducing CH4 emissions. The identity, activity, and metabolic processes of anaerobic methane oxidizers are poorly understood, yet this information is critical to understanding CH4 cycling and ultimately to predicting future CH4 emissions. This study sought to identify the microorganisms involved in AOM in sub-Arctic lake sediments using DNA- and phospholipid-fatty acid (PLFA)- based stable isotope probing. Results indicated that aerobic methanotrophs belonging to the genus Methylobacter assimilate carbon from CH4, either directly or indirectly. Other organisms that were found, in minor proportions, to assimilate CH4-derived carbon were methylotrophs and iron reducers, which might indicate the flow of CH4-derived carbon from anaerobic methanotrophs into the broader microbial community. While various other taxa have been reported in the literature to anaerobically oxidize methane in various environments (e.g. ANME-type archaea and Methylomirabilis Oxyfera), this report directly suggest that Methylobacter can perform this function, expanding our understanding of CH4 oxidation in anaerobic lake sediments.
PubMed ID
28686892 View in PubMed
Less detail

[Analysis of Phytoplankton in Tsimlyansk Reservoir (RUSSIA) for the Presence of Cyanobacterial Hepato- and Neurotoxins].

https://arctichealth.org/en/permalink/ahliterature271687
Source
Mikrobiologiia. 2015 Nov-Dec;84(6):732-42
Publication Type
Article
Author
S I Sidelev
T B Golokolenova
E N Chernova
I V Russkikh
Source
Mikrobiologiia. 2015 Nov-Dec;84(6):732-42
Language
Russian
Publication Type
Article
Keywords
Bacterial Toxins - analysis
Lakes - microbiology
Microcystis - growth & development
Neurotoxins - analysis
Phytoplankton - growth & development
Russia
Water Microbiology
Abstract
Although the water bodies of southern Russia experience the most extreme effects of cyanobacterial blooms, molecular genetic data on the composition of toxigenic cyanobacteria in this region have been absent. Screening for the genes responsible for the synthesis of hepatotoxins (microcystins and cylindrospermopsin) and neurotoxins (anatoxin-a and saxitoxins) in cyanobacteria from the Tsimlyansk reservoir on the Don River was carried out. The presence of microcystin-producing Microcystis and Planktothrix populations, as well as of cyanobacteria capable of synthesis of a neurotoxin anatoxin-a was revealed by polymerase chain reaction (PCR). A hypothesis of the presence of anatoxin-a-producing Planktothrix rubescens population in the phytoplankton of the Tsimlyansk reservoir is proposed. The obtained PCR data were confirmed by the results of enzyme-linked immunosorbent assay (ELISA) and liquid chromatography/mass-spectrometry (LC/MS). Anatoxin-a and five microcystin variants were identified in the phytoplankton biomass.
PubMed ID
26964363 View in PubMed
Less detail

Anatoxin-a producing Tychonema (Cyanobacteria) in European waterbodies.

https://arctichealth.org/en/permalink/ahliterature266912
Source
Water Res. 2015 Feb 1;69:68-79
Publication Type
Article
Date
Feb-1-2015
Author
S. Shams
C. Capelli
L. Cerasino
A. Ballot
D R Dietrich
K. Sivonen
N. Salmaso
Source
Water Res. 2015 Feb 1;69:68-79
Date
Feb-1-2015
Language
English
Publication Type
Article
Keywords
Chromatography, Liquid
Cyanobacteria - isolation & purification - metabolism
Environment
Italy
Lakes - microbiology
Mass Spectrometry
Norway
Phylogeny
Polymerase Chain Reaction
Sequence Analysis, DNA
Surface Properties
Tropanes - metabolism
Abstract
In order to identify the cyanobacterial species responsible of anatoxin-a (ATX) production in Lake Garda (Northern Italy), an intensive isolation and culturing of filamentous cyanobacteria were established since 2014 from environmental samples. In this work, we report a detailed account of the strategy adopted, which led to the discovery of a new unexpected producer of ATX, Tychonema bourrellyi. So far, this species is the first documented example of cultured Oscillatoriales able to produce ATX isolated from pelagic freshwater ecosystems. The isolated filaments were identified adopting a polyphasic approach, which included microscopic species identification, genetic characterisation and phylogenetic analyses based on 16S rRNA genes. The taxonomic identification was further confirmed by the high (>99%) rbcLX sequence similarities of the T. bourrellyi strains of Lake Garda with those deposited in DNA sequence databases. More than half of the isolates were shown to produce a significant amount of ATX, with cell quota ranging between 0.1 and 2.6 µg mm(-3), and 0.01 and 0.35 pg cell(-1). The toxic isolates were tested positive for anaC of the anatoxin-a synthetase (ana) gene cluster. These findings were confirmed with the discovery of one ATX producing T. bourrellyi strain isolated in Norway. This strain and a further non-ATX producing Norwegian Tychonema bornetii strain tested positive for the presence of the anaF gene of the ana gene cluster. Conversely, none of the Italian and Norwegian Tychonema strains were positive for microcystins (MCs), which was also confirmed by the absence of mcyE PCR products in all the samples analysed. This work suggests that the only reliable strategy to identify cyanotoxins producers should be based on the isolation of strains and their identification with a polyphasic approach associated to a concurrent metabolomic profiling.
PubMed ID
25437339 View in PubMed
Less detail

[Anoxygenic phototrophic bacteria from microbial communities of Goryachinsk Thermal Spring (Baikal Area, Russia)].

https://arctichealth.org/en/permalink/ahliterature262069
Source
Mikrobiologiia. 2014 Jul-Aug;83(4):484-99
Publication Type
Article
Author
A M Kalashnikov
V A Gaisin
M V Sukhacheva
B B Namsaraeva
A N Panteleeva
E N Nuianzina-Boldareva
B B Kuznetsov
V M Gorlenko
Source
Mikrobiologiia. 2014 Jul-Aug;83(4):484-99
Language
Russian
Publication Type
Article
Keywords
Bacteria - classification - genetics - metabolism
Hot Springs - microbiology
Lakes - microbiology
Microbial Consortia - physiology
Phototrophic Processes - physiology
Phylogeny
Siberia
Abstract
Species composition of anoxygenic phototrophic bacteria in microbial mats of the Goryachinsk thermal spring was investigated along the temperature gradient. The spring belonging to nitrogenous alkaline hydrotherms is located at the shore of Lake Baikal 188 km north-east from Ulan-Ude. The water is of the sulfate-sodium type, contains trace amounts of sulfide, salinity does not exceed 0.64 g/L, pH 9.5. The temperature at the outlet of the spring may reach 54 degrees C. The cultures of filamentous anoxygenic phototrophic bacteria, nonsulfur and sulfur purple bacteria, and aerobic anoxygenic phototrophic bacteria were identified using the pufLM molecular marker. The fmoA marker was used for identification of green sulfur bacteria. Filamentous cyanobacteria predominated in the mats, with anoxygenic phototrophs comprising a minor component of the phototrophic communities. Thermophilic bacteria Chloroflexus aurantiacus were detected irn the samples from both the thermophilic and mesophilic mats. Cultures ofnonsulfur purple bacteria similar to Blastochloris sulfoviridis and Rhodomicrobium vannielii were isolatd from the mats developing at high (50.6-49.4 degrees C) and low temperatures (45-20 degrees C). Purple sulfur bacteria Allochromatium sp. and Thiocapsa sp., as well as green sulfur bacteria Chlorobium sp., were revealedin low-temperature mats. Truly thermophilic purple and gree sulfur bacteria were not found in the spring. Anoxygenic phototrophic bacteria found in the spring were typical of the sulfuret communities, for which the sulfur cycle is mandatory. The presence of aerobic bacteriochlorophylla-containing bacteria identified as Agrobacterium (Rhizobium) tumifaciens in the mesophilic (20 degrees C) mat is of interest.
PubMed ID
25844460 View in PubMed
Less detail

Application of a new cultivation technology, I-tip, for studying microbial diversity in freshwater sponges of Lake Baikal, Russia.

https://arctichealth.org/en/permalink/ahliterature259327
Source
FEMS Microbiol Ecol. 2014 Nov;90(2):417-23
Publication Type
Article
Date
Nov-2014
Author
Dawoon Jung
Eun-Young Seo
Slava S Epstein
Yochan Joung
Jaemin Han
Valentina V Parfenova
Olga I Belykh
Anna S Gladkikh
Tae Seok Ahn
Source
FEMS Microbiol Ecol. 2014 Nov;90(2):417-23
Date
Nov-2014
Language
English
Publication Type
Article
Keywords
Animals
Bacteria - classification - genetics - growth & development
Bacteriological Techniques
DNA, Bacterial - genetics
Lakes - microbiology
Phylogeny
Porifera - microbiology
RNA, Ribosomal, 16S - genetics
Russia
Abstract
One of the fundamental methods for cultivating bacterial strains is conventional plating on solid media, but this method does not reveal the true diversity of the bacterial community. In this study, we develop a new technique and introduce a new device we term, I-tip. The I-tip was developed as an in situ cultivation device that allows microorganisms to enter and natural chemical compounds to diffuse, thereby permitting the microorganisms to grow utilizing chemical compounds in their natural environment. The new method was used to cultivate microorganisms from Baikalian sponges, and the results were compared with conventional plating as well as a pyrosequencing-based molecular survey. The I-tip method produced cultures of 34 species from five major phyla, Actinobacteria, Alphaproteobacteria, Betaproteobacteria, Firmicutes, and Gammaproteobacteria, 'missing' only two major phyla detected by pyrosequencing. Meanwhile, standard cultivation produced a smaller collection of 16 species from three major phyla, Betaproteobacteria, Firmicutes, and Gammaproteobacteria, failing to detect over half of the major phyla registered by pyrosequencing. We conclude that the I-tip method can narrow the gap between cultivated and uncultivated species, at least for some of the more challenging microbial communities such as those associated with animal hosts.
PubMed ID
25078251 View in PubMed
Less detail

Assessing microbial contamination and antibiotic resistant bacteria using zebra mussels (Dreissena polymorpha).

https://arctichealth.org/en/permalink/ahliterature296517
Source
Sci Total Environ. 2019 Feb 10; 650(Pt 2):2141-2149
Publication Type
Journal Article
Date
Feb-10-2019
Author
Maria Alexandra Bighiu
Anna Norman Haldén
Willem Goedkoop
Jakob Ottoson
Author Affiliation
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), Sweden. Electronic address: maria.bighiu@slu.se.
Source
Sci Total Environ. 2019 Feb 10; 650(Pt 2):2141-2149
Date
Feb-10-2019
Language
English
Publication Type
Journal Article
Keywords
Animals
Anti-Bacterial Agents - pharmacology
Dreissena - microbiology
Drug Resistance, Bacterial
Enterococcus - drug effects - isolation & purification
Environmental Monitoring - methods
Escherichia coli - drug effects - isolation & purification
Lakes - microbiology
Sweden
Waste Water - microbiology
Abstract
Aquatic pollution with faecal bacteria and subsequent consumption of contaminated water or food is a worldwide issue that causes severe health effects (e.g. meningitis, salmonellosis, dysentery). In addition, the excessive use of antibiotics in animal husbandry and human medicine has enhanced the selective pressure on pathogenic bacteria, further increasing human health risks and detrimental effects on natural microbial communities. This urges the need to monitor faecal contamination using a time-integrated approach, as grab water samples can miss pathogen peaks. We tested the ability of zebra mussels (Dreissena polymorpha) to take up and depurate faecal indicator bacteria such as Escherichia coli and intestinal enterococci. Furthermore, we quantified the frequency of antibiotic resistant bacteria in water and mussels both in controlled laboratory tests and under in situ conditions downstream of a sewage treatment plant (STP). Laboratory results show that bacterial indicators in mussels were 132 times higher than their concentration in water, and that mussels retained bacteria up to 2?days after pulse exposure. Field results show decreasing bacterial concentrations in both water and mussels downstream the STP, with maximum E. coli concentrations ranging 173-9?cfu?mL-1 in water and 2970-330?cfu?g-1 in mussels. Similarly, enterococci ranged 59-4?cfu?mL-1 and 1450-240?cfu?g-1 in water and mussels, respectively. High proportions of antibiotic resistant E. coli were found in mussels (72%) and water (65%), and slightly lower proportion of resistant enterococci was found in mussels (47%) and in water (34%). Moreover, 33% of the bacteria isolated from mussels were resistant to multiple antibiotics, which emphasizes that resistance is a common feature in surface waters and highlights the need for safe water management. Our results show that zebra mussels provide an efficient, time-integrating tool for quantifying faecal indicators, including resistant and multidrug resistant bacteria.
PubMed ID
30290355 View in PubMed
Less detail

45 records – page 1 of 5.