Microbial communities associated with acetate-rich gas-petroleum reservoir surface facilities

We evaluated the microbial communities in acetate-rich production waters from separators of a high-temperature gas-petroleum reservoir in Higashi-Niigata, Japan. Bacterial and archaeal 16S rRNA gene libraries constructed from these waters were dominated by Acetobacterium-, Methanofollis-, and Methanosarcina-related sequences. The libraries constructed from enrichment cultures of the production waters were dominated by sequences related to the Acetobacterium- and Methanofollis-related sequences.     

Bromoperoxidase activity and vanadium level of the brown alga Ascophyllum nodosum

Vanadium-dependent peroxidase activity in extracts of Ascophyllum nodosum growing in the intertidal region close to Roscoff/France, and algal vanadium levels, followed approximately similar seasonal variation, as deduced from a study lasting from April 2005 to March 2006. High peroxidase (PO) activity was found in extracts obtained from algae collected in between midwinter to spring [∼100-190 U per g dry mass (dm), triiodide assay] with a maximum in April. Periods of reduced PO activity lasted from summer to early winter (∼50-90 U per g dm). High vanadium levels (1.5-2.2 mg kg⁻¹ dm) were found in algae collected from midwinter to spring, whereas reduced levels (0.6-1.4 mg kg⁻¹ dm) were found in summer to early winter.     

Microbial populations associated with fixed- and floating-bed reactors during a two-stage anaerobic process

Microbial populations associated with methanogenic fixed- or floating-bed bioreactors used for anaerobic digestion of lignocellulosic waste were investigated. Fluorescent in situ hybridization (FISH) was used to characterize microorganisms in samples obtained from different heights in the reactors, which were operated in a semi-continuous manner (feeding and mixing once every 2 days). The FISH results showed that Methanosaeta concilii cells were most numerous at the bottom of both reactors. M. concilii cells were more abundant in the fixed-bed reactor (FXBR), which performed better than the floating-bed reactor (FLBR). Species of the Methanosarcina genera (mainly M. barkeri and M. mazei) were also observed in the FLBR but rarely in the FXBR. Methane production in each of the reactors ranged from 0.29 to 0.33 m3 CH(4)/kg COD(rem) (chemical oxygen demand removed). The removal of volatile fatty acids (VFA; 70-75 h) in the FXBR was more efficient than in the FLBR.     

Microbial flora associated with colonized and wild populations of the biting gnat Culicoides variipennis

Comparisons were made between the microbial flora in a natural breeding site and in the rearing medium of a laboratory colony and between microbial flora of wild and colonized flies of the biting gnat Culicoides variipennis. Members of the microbial flora at both the natural site and in the colony rearing medium were mostly common contaminants of polluted water; e.g., Enterobacter, Flavobacterium, and Pseudomonas. Anaerobic bacteria (Clostridium spp. & Bacteroides spp.) and the diatom Navicula were found at the natural breeding site, but were not found in the colony rearing medium. The microbial flora isolated from pupae and adults of both wild and colonized flies was similar to that in the natural breeding site and the colony rearing medium. There was no evidence of a specific association of any bacterial genus with either larvae, pupae, or adult flies in the laboratory colony.

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Zusammenfassung Die Gnitze Culicoides variipennis ist der Vektor des Virusagens der wirtschaftlich wichtigen und weit verbreiteten Blauzungenkrankheit von Rindern, Schafen und wilden Wiederkäuern. Für die Entwicklung einer Technik zur Krankheitsbekämpfung ist eine große Zahl von Mücken notwendig. Eine Bakterienmikroflora ist zur Zeit unentbehrlich für das Zuchtmedium, das zur Erzeugung der Mücken gebraucht wird. Aus diesem Grunde wurden Mikroorganismen, die mit verschiedenen Stadien der Mücken verbunden sind, identifiziert. Für die Mücken waren keine spezifischen Bakteriengenera erforderlich, was darauf hinweist, daß schon jedweder von verschiedenen Mikroorganismen eine günstige Nahrungsquelle für die Mücken darstellt. Diese Befunde erwiesen sich als vorteilhaft für die Laborzucht der Mücken, was wiederum für die Untersuchungen zur Bekämpfung und Ausrottung der Blauzungenkrankheit beim Viehsbestand von Nutzen ist.

     

Management and production of the brown algae Ascophyllum nodosum in the Canadian maritimes

Commercial exploitation of Ascophyllum nodosum (rockweed) along the coast of Nova Scotia began in the late 1950s when it was used as a raw material for manufacturing alginate and “kelp” meal. Today, this resource is used as a biostimulant extract for crops and animal feed supplements and is the main economic resource of the seaweed industry in the Maritime Provinces and Canada. The management of rockweed, by dividing the resource into many sectors, permitted the assessment of yield per unit area of bed. In Nova Scotia, mechanical harvesting of A. nodosum operated on a pulse of 2- to 3-year schedule providing yields of 21.9 to 47.7?wet?t ha^?1 averaging 35.3?±?7.6?wet?t ha^?1. Acadian Seaplants Limited (ASL) has become the dominant player in the region since 1995 with more than 75% of the total biomass under its leases and more than 90% of the total landing of rockweed in the last 13?years. Sustained harvests at ASL leases and under an annual harvest schedule using hand cutting methods have averaged 17.4?±?2.6?t ha^?1. Exploitation rates above 35% of the harvestable crop lead to a pulse harvest strategy and the need to move infrastructure year after year. In New Brunswick, a new approach to management began in 1995 with a regulated 17% exploitation rate. Thus, the yield in that province is 14.3?wet?t ha^?1. The current summer standing crop for this region has been calculated at 352,723?wet?t, covering an area of 4,960?ha, with an average biomass of 71.3?t ha^?1. The harvest in the region reached peak landings in 2010 with just over 40,100?t. The consistent yield per hectare of A. nodosum beds is proof of good management practices and an ecologically sustainable harvest in the Canadian Maritimes.     

The brown alga Ascophyllum nodosum contains two different vanadium bromoperoxidases

Haloperoxidases have been detected in a variety of organisms, including bacteria, fungi, algae, and mammals. Mammalian haloperoxidases are known to be directly involved in the oxidative destruction of microorganisms. The algal bromoperoxidases are probably involved in the biosynthesis of bromometabolites, most of which show considerable bactericidal activity. From the brown seaweed Ascophyllum nodosum (order, Fucales) two different bromoperoxidases have been isolated, which both contain vanadium as an essential element for enzymic activity. The location of these two enzymes, determined by activity staining of cross-sections of algal parts, was different. Bromoperoxidase I (which has been described before) was located inside the thallus, particularly around the conceptacles, whereas bromoperoxidase II was present at the thallus surface of the alga. The molecular masses of these bromoperoxidases as judged from sodium dodecyl sulfate-gel electrophoresis were 97 and 106 kDa, respectively. Some of the enzymatic properties (pH optimum and Km for bromide) of the two enzymes were slightly different, whereas the amino acid compositions were more or less equal. The isoelectric point of the two proteins was the same, namely 5.0. On sodium dodecyl sulfate-polyacrylamide gels both enzymes could be stained with periodic acid Schiff's reagent, so both are glycoproteins. Since only bromoperoxidase II could be bound to a concanavalin A-Sepharose column, these enzymes contain different carbohydrates. Both enzymes display a considerable thermostability. However, the chemical stability of the two bromoperoxidases differed. Bromoperoxidase II could also be inactivated by dialysis at low pH and reactivation was only possible with the transition metal vanadium and not with other metal ions. The presence of vanadium in this enzyme could be established with atomic absorption spectrophotometry and electron paramagnetic resonance. The EPR signals of both bromoperoxidases, which were observed after reduction with sodium dithionite, were similar: only minor differences were observed in the hyperfine coupling. In immunoblotting experiments these two bromoperoxidases were found to cross-react, so they have common antigenic determinants.     

Microbial population and functional dynamics associated with surface potential and carbon metabolism

Microbial extracellular electron transfer (EET) to solid surfaces is an important reaction for metal reduction occurring in various anoxic environments. However, it is challenging to accurately characterize EET-active microbial communities and each member''s contribution to EET reactions because of changes in composition and concentrations of electron donors and solid-phase acceptors. Here, we used bioelectrochemical systems to systematically evaluate the synergistic effects of carbon source and surface redox potential on EET-active microbial community development, metabolic networks and overall electron transfer rates. The results indicate that faster biocatalytic rates were observed under electropositive electrode surface potential conditions, and under fatty acid-fed conditions. Temporal 16S rRNA-based microbial community analyses showed that Geobacter phylotypes were highly diverse and apparently dependent on surface potentials. The well-known electrogenic microbes affiliated with the Geobacter metallireducens clade were associated with lower surface potentials and less current generation, whereas Geobacter subsurface clades 1 and 2 were associated with higher surface potentials and greater current generation. An association was also observed between specific fermentative phylotypes and Geobacter phylotypes at specific surface potentials. When sugars were present, Tolumonas and Aeromonas phylotypes were preferentially associated with lower surface potentials, whereas Lactococcus phylotypes were found to be closely associated with Geobacter subsurface clades 1 and 2 phylotypes under higher surface potential conditions. Collectively, these results suggest that surface potentials provide a strong selective pressure, at the species and strain level, for both solid surface respirators and fermentative microbes throughout the EET-active community development.     

Erythema nodosum associated with pregnancy and oral contraceptives.

Erythema nodosum recurred in a woman during each of her four pregnancies and every time she was started on oral contraceptives. The lesions always disappeared in the fifth month of gestation or when contraceptives were withdrawn. Erythema nodosum is mediated by immune mechanisms, and both pregnancy and oral contraceptive use can interfere with the immune system. The concentrations of oestrogen and progesterone or the ratio between them may be critical to the development of erythema nodosum. The observation that the lesions spontaneously resolved in the fifth month of pregnancy supports this hypothesis.     

Antidiabetic properties of polysaccharide- and polyphenolic-enriched fractions from the brown seaweed Ascophyllum nodosum

We screened seaweed species from Atlantic Canada for antidiabetic activity by testing extracts for alpha-glucosidase inhibitory effect and glucose uptake stimulatory activity. An aqueous ethanolic extract of Ascophyllum nodosum was found to be active in both assays, inhibiting rat intestinal alpha-glucosidase (IC50 = 77 microg/mL) and stimulating basal glucose uptake into 3T3-L1 adipocytes during a 20-minute incubation by about 3-fold (at 400 microg/mL extract). Bioassay-guided fractionation of the A. nodosum extract showed that alpha-glucosidase inhibition was associated with polyphenolic components in the extract. These polyphenolics, along with other constituents appeared to be responsible for the stimulatory activity on glucose uptake. However, attempts to further concentrate this activity through fractionation techniques were unsuccessful. A crude polyphenol extract (PPE), an enriched polyphenolic fraction (PPE-F1) and a polysaccharide extract (PSE) were prepared from commercial A. nodosum powder and administered to streptozotocin-diabetic mice for up to 4-weeks by daily gavage at 200 mg/kg body mass. PPE and PPE-F1 improved fasting serum glucose level in diabetic mice; however, the effect was only statistically significant at day 14. In addition, PPE-F1 was shown to blunt the rise in blood glucose after an oral sucrose tolerance test in diabetic mice. Mice treated with PPE and PPE-F1 had decreased blood total cholesterol and glycated serum protein levels compared with untreated diabetic mice, whereas PPE also normalized the reduction in liver glycogen level that occurred in diabetic animals. All 3 A. nodosum preparations improved blood antioxidant capacity.     

Microbial processes and bacterial populations associated to anaerobic treatment of sulfate-rich wastewater

A pilot-scale (1.2 m³) anaerobic sequencing batch biofilm reactor (ASBBR) containing mineral coal for biomass attachment was fed with sulfate-rich wastewater at increasing sulfate concentrations. Ethanol was used as the main organic source. Tested COD/sulfate ratios were of 1.8 and 1.5 for sulfate loading rates of 0.65–1.90 kgSO₄²⁻/cycle (48 h-cycle) or of 1.0 in the trial with 3.0 gSO₄²⁻ l⁻¹. Sulfate removal efficiencies observed in all trials were as high as 99%. Molecular inventories indicated a shift on the microbial composition and a decrease on species diversity with the increase of sulfate concentration. Beta-proteobacteria species affiliated with Aminomonas spp. and Thermanaerovibrio spp. predominated at 1.0 gSO₄²⁻ l⁻¹. At higher sulfate concentrations the predominant bacterial group was Delta-proteobacteria mainly Desulfovibrio spp. and Desulfomicrobium spp. at 2.0 gSO₄²⁻ l⁻¹, whereas Desulfurella spp. and Coprothermobacter spp. predominated at 3.0 gSO₄²⁻ l⁻¹. These organisms have been commonly associated with sulfate reduction producing acetate, sulfide and sulfur. Methanogenic archaea (Methanosaeta spp.) was found at 1.0 and 2.0 gSO₄²⁻ l⁻¹. Additionally, a simplified mathematical model was used to infer on metabolic pathways of the biomass involved in sulfate reduction.     

Structural studies on ascophyllan and the fucose-containing complexes from the brown alga Ascophyllum nodosum

The two major “complexes” isolated from a dilute-acid extract of Ascophyllum nodosum were degraded by mild, acid hydrolysis to a fucan portion and an ascophyllan-like portion. Protein was enriched in the ascophyllan-like fraction. A time-course study of the acid hydrolysis, together with data on digestion by pronase and hydrolysis by base indicated that the complexes were formed by a fucan backbone to which varyious numbers of ascophyllan-like molecules were attached by an acid-labile linkage. The primary uronic acid in the ascophyllan-like portion of the complex was mannuronic acid, whereas the free ascophyllan isolated in this study contained a mixture of guluronic, mannuronic, and glucuronic acids*. In each of these uronic acid-rich materials, hydrolysis by base suggested a uronic acid backbone having relatively long, fucose-containing, side chains. Hydroxyproline was present in the complex, but did not appear to be part of the major carbohydrate-protein linkages. A protein-enriched fraction was obtained by treatment of the ascophyllan-like portion of the complex with oxalic acid. Amino acid analysis, before and after treatment with mild base suggested that serine and threonine were involved in the linkage of protein to carbohydrate.     

Microbial populations associated with treatment of an industrial dye effluent in an anaerobic baffled reactor.

Fluorescent in situ hybridization (FISH) using 16S and 23S rRNA-targeted probes together with construction of an archaeal 16S ribosomal DNA (rDNA) clone library was used to characterize the microbial populations of an anaerobic baffled reactor successfully treating industrial dye waste. Wastewater produced during the manufacture of food dyes containing several different azo and other dye compounds was decolorized and degraded under sulfidogenic and methanogenic conditions. Use of molecular methods to describe microbial populations showed that a diverse group of Bacteria and Archaea was involved in this treatment process. FISH enumeration showed that members of the gamma subclass of the class Proteobacteria and bacteria in the Cytophaga-Flexibacter-Bacteroides phylum, together with sulfate-reducing bacteria, were prominent members of a mixed bacterial population. A combination of FISH probing and analysis of 98 archaeal 16S rDNA clone inserts revealed that together with the bacterial population, a methanogenic population dominated by Methanosaeta species and containing species of Methanobacterium and Methanospirillum and a relatively unstudied methanogen, Methanomethylovorans hollandica, contributed to successful anaerobic treatment of the industrial waste. We suggest that sulfate reducers, or more accurately sulfidogenic bacteria, together with M. hollandica contribute considerably to the treatment process through metabolism of dye-associated sulfonate groups and subsequent conversion of sulfur compounds to carbon dioxide and methane.     

Microbial populations in trifluralin-treated soil

Summary This study examined the effects of trifluralin (,,-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), a soil incorporated herbicide, on soil microflora both in the general soil environment and in the rhizosphere of trifluralin damaged wheat roots. Two Dark Brown Chernozemic soils were treated with various trifluralin rates in the growth chamber and wheat [Triticum aestivum L. Neepawa] was seeded. Trifluralin generally had no effect on fungi, bacteria, or actinomycete populations in either the general soil or in the rhizosphere. CO₂ evolution was unchanged when trifluralin was added to the soil. In wheat plots, at two field locations, there were no significant effects of trifluralin (1.0 kg ha^–1) on soil fungi, bacteria, actinomycete, denitrifying bacteria, and nitrifying Nitrobacter propulations. A pure culture study with 42 soil microorganisms showed that many isolates were inhibited at 400 to 100,000 g g^–1 but not at concentrations <16 g g^–1. Similar data were obtained from tests on four different soils. These studies indicate that trifluralin is unlikely to cause changes in the numbers of soil microorganisms when used at recommended levels.     

Microbial oxidation of elemental sulphur in brown soil

Plant and Soil - Brown soil formed from loamy clay was examined for its ability to produce sulphate from added elemental suphur. At higher rates of sulphur applications the pH of a slightly acid...     

Microbial community associated with the colonial ascidian Cystodytes dellechiajei

The ascidian Cystodytes dellechiajei (Della Valle, 1877) (phylum Chordata, class Ascidiacea, family Polycitoridae) is a colonial tunicate that inhabits benthic rock environments in the Atlantic, Pacific and Indian Oceans, as well as the Mediterranean Sea. Its life cycle has two phases, the adult sessile colony and the free-living larva. Both adult zooids and larvae are surrounded by a protective tunic that contains several eukaryotic cell lines, is composed mainly of acidic mucopolysacharides associated with collagen and elastin-like proteins, and is covered by a thin cuticle. The microbiota associated with the tunic tissues of adult colonies and larva of C. dellechiajei has been examined by optical, confocal and electron microscopy and by fluorescence in situ hybridization (FISH), denaturing gradient gel electrophoresis (DGGE), and 16S rRNA gene clone library analysis. Microscopy analyses indicated the presence inside the tunic, both for the adult and the larva, of a dense community of Bacteria while only the external surface of colony cuticle was colonized by diatoms, rodophyte algae and prokaryotic-like epiphytes. Transmission electron microscopy showed tunic eukaryotic cells that were engulfing and lysing bacteria. 16S rRNA gene analyses (DGGE and clone libraries) and FISH indicated that the community inside the tunic tissues of the adults and larvae was dominated by Alphaproteobacteria. Bacteria belonging to the phyla Gammaproteobacteria and Bacteroidetes were also detected in the adults. Many of the 16S rRNA gene sequences in the tunic tissues were related to known aerobic anoxygenic phototrophs (AAP), like Roseobacter sp. and Erythrobacter sp. In order to check whether the gene pufM, coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis, was being expressed inside the ascidian tissues, two libraries, one for an adult colony and one for larva, of cDNA from the expressed pufM gene were also constructed. The sequences most frequently (64% for colony and 67% for larva) retrieved from these libraries presented > 90% aa identity with the pufM gene product of the Roseobacter-like group, a cluster of AAP widely detected in marine planktonic environments.