Isolation of anaerobic, extremely thermophilic, sulphur metabolising archaebacteria from New Zealand hot springs

Enrichments of New Zealand geo-thermal samples, initiated in anaerobic sulphur-containing media and incubated at temperatures above 85°C, yielded rod and coccal shaped organisms which possessed archaebacterial characteristics. Pure cultures were isolated and characterised. Five of the seven isolates, which were rod-shaped organisms and did not have an obligate requirement for sulphur respiration, were similar to Ther-moproteus sp. but had more neutral pH optima for growth. Three of these five Thermoproteus sp. were obligate heterotrophs, which has not previously been reported. The two coccal isolates had an obligate requirement for sulphur as an electron acceptor and were similar to Desulfurococcus sp. but again with more neutral pH optima for growth

Prospects and Present Status and of Entomopathogenic Nematodes (Steinernematidae and Heterorhabditidae) in Nepal

Naturally occurring entomopathogenic nematodes(EPN) and their symbiotic bacteria are important biotic factor in suppression of insect pest populations in soil and cryptic habitats. These nematodes can control pests due to their mutualistic association with bacteria that kill the hosts by septicemia and make the environment favorable for EPN development and reproduction.The virulent species of EPN can commercially be mass produced as biological control agents all over the world. Nepal  has a great potential to exploit these beneficial nematodes for the control of insect pests. Exploration of indigenous EPN is receiving attention around th eworld. Numerous surveys conducted worldwide have detected many indigenous isolates. Altogether 115 species of EPN (97 of Steinernema and 18 of Heterorhabdits species) have been reported so far worldwide. However, very limited research on EPN in Nepal has been done with 29 species only with some new species. Hence,the isolation and description of the native efficacious species and populationsof EPN is the need of the hour,not only from a biodiversity view point but also from an environmental and biological control perspective.Thei dentification of EPNs, adapted to environmental and climatic conditions of cultivated areas, is important for sustainable pest suppression in integrated management programs in agricultural areas of Nepal. This article provides an overview of recent development on EPN research and evaluates their potential for use and exploitation in Nepal

Аргументация как лингвистический элемент в полемике. Виды аргументов

Thermoanaerobacter brockiifermented serine to acetate and ethanol. It oxidized leucine to isovalerate, isoleucine to 2-methylbutyrate, and valine to isobutyrate only in the presence of thiosulfate, or when co-cultured withMethanobacteriumsp. This oxidative deamination was rendered thermodynamically possible by the ability ofT. brockiito reduce thiosulfate to sulfide or the transfer of reducing equivalents to the hydrogenotrophic methanogen. The results suggest thatT. brockiimay be of ecological significance in thermal environments in the turnover of amino acids, especially with thiosulfate or H2-utilizing methanogens are present

Влияние автономного инвертора напряжения с синусоидальной широтно-импульсной модуляцией на устойчивость системы электропривода

A method for calculating conditions subharmonic stable AC systems, taking into account the discrete of voltage autonomous inverter with sinusoidal PWM based on which the stable area of AC engine drive

Isolation and characterization of Halothermothrix orenii gen. nov., sp. nov., a halophilic, thermophilic, fermentative, strictly anaerobic bacterium

The occurrence of thermophilic, halophilic anaerobic bacteria in the sediment of a Tunisian salted lake was tested in samples collected at 20-cm intervals down to a depth of 1.20 m. A long rod, present only in the 40-to 60-cm layer, was isolated at 60°C in a medium containing 100 g of NaCl per liter and designated strain H168. This strain produced acetate, ethanol, H2, and CO2 from glucose metabolism. Fructose, xylose, ribose, cellobiose, and starch were also oxidized. The optimum temperature for growth was 60°C. No growth was obtained at 42 or 70°C. Strain H168 grew optimally in NaCl concentrations ranging from 50 to 100 g per liter, with the upper and lower limits of growth around 200 and 40 g per liter, respectively. The G+C ratio of the DNA was 39.6 mol %. Although halophilic, moderately thermophilic bacteria have been characterized among anaerobes, particularly within methanogens, strain H168 is the first true thermophilic (growing above 60°C) halophilic anaerobic bacterium described so far. The phylogeny, physiology, morphology, lipid content, and high G+C content of strain H168 are sufficiently different from those of genera belonging to the family Haloanaerobiaceae to justify the definition of a new genus

Peptide and amino acid oxidation in the presence of thiosulfate by members of the genus Thermoanaerobacter

#Thermoanaerobacter brockii, #T. ethanolicus, #T. thermohydrosulfuricus, #T. finnii, and #Thermoanaerobacter strain SEBR 5268 (an isolate from an oil-producting well) were studied for their ability to oxidize proteinaceous compounds that included gelatin, peptides, and casamino acids. All bacteria tested used peptides and amino acids, but only slightly. However, in the presence of thiosulfate all the #Thermoanaerobacter species showed a substantial improvement in growth and/or the production of acetate, isovalerate, isobutyrate, and sulfide. Propionate was a minor product of peptide or amino acid oxidation. The reduction of thiosulfate during growth on peptides by members of the #Thermoanaerobacter$ species is a trait that closely resembles that of archaeal hyperthermophiles during growth on peptides and amino acids with elemental sulfur as electron acceptor. (Résumé d'auteur

Effect of thiosulphate as electron acceptor on glucose and xylose oxidation by Thermoanaerobacter finnii and Thermoanaerobacter sp. isolated from oil field water

#Thermoanaerobacter finnii fermente le glucose et le xylose en lactate, acétate, H2, CO2 et éthanol qui est le produit majeur du métabolisme. Une autre bactérie du genre #Thermoanaerobacter isolée d'une eau de gisement pétrolier produit des quantités aussi importantes d'éthanol que de lactate à partir de ces sucres. L'oxydation du glucose et du xylose par ces deux micro-organismes est complètement modifiée en présence de thiosulfate puisque, dans ces conditions, l'acétate devient le produit majeur du métabolisme des sucres. Cette modification du métabolisme amène à de meilleurs rendements cellulaires et à un meilleur taux de croissance bactérienne lorsque le thiosulfate est utilisé comme accepteur d'électrons. Une plus grande production d'acétate en présence de thiosulfate indique que les bactéries testées récupèrent plus d'énergie des phosphorylations liées au substrat. Ces modifications observées sur le métabolisme des sucres en présence de thiosulfate nous amènent à tenir compte plus précisément du rôle que peut jouer cet accepteur d'électrons dans l'oxydation de la matière organique dans les sources chaudes riches en sulfate sulfuré ou les eaux de gisements pétroliers. (Résumé d'auteur

Identification of thiosulfate- and sulfur -reducing bacteria unable to reduce sulfate in ricefield soils

Eighteen strains of anaerobic thiosulfate-reducing bacteria unable to use sulfate as electron acceptor (TSRnSR) were isolated from four ricefield soils originating from France and the Philippines, using peptides as energy sources, H2 as electron donor, thiosulfate as electron acceptors, and four enrichment methods to vary the selection pressure. They were strict proteolytic asaccharolytic anaerobes producing H2S when grown on thiosulfate + H2. They exhibited the same RFLP profile (11 restriction enzymes tested). Partial sequencing of the 16S rDNA showed that they belonged to the genus Clostridium and were phylogenetically related to C. subterminale. DNA-DNA hybridization of a representative strain with the closest C. subterminale strain (DSM 6970T) yielded a value of 68.9%. Previous counts of TSRnSR in ricefield soils, their identification as Clostridium strains, and the known ubiquity of this genus in such soils indicate that TSRnSR may play a significant role in S cycling in some wetland soils. (Résumé d'auteur