The use of morphokinetics as a predictor of embryo implantation.

Background: Time-lapse observation presents an opportunity for optimizing embryo selection based on morphological grading as well as providing novel kinetic parameters, which may further improve accurate selection of viable embryos. The objective of this retrospective study was to identify the morphokinetic parameters specific to embryos that were capable of implanting. In order to compare a large number of embryos, with minimal variation in culture conditions, we have used an automatic embryo monitoring system.

Pericellular oxygen depletion during ordinary tissue culturing, measured with oxygen microsensors.

Recent research has found important differences in oxygen tension in proximity to certain mammalian cells when grown in culture. Oxygen has a low diffusion rate through cell culture media, thus, as a result of normal respiration, a decrease in oxygen tension develops close to the cells. Therefore, for the purpose of standardization and optimization, it is important to monitor pericellular oxygen tension and cell oxygen consumption.

Nitrification-denitrification dynamics and community structure of ammonia oxidizing bacteria in a high yield irrigated Philippine rice field.

Nitrogen is the single most limiting factor for rice production. Detailed knowledge on nitrogen dynamics in rice fields is therefore of major importance for developing sustainable rice production. A combination of state-of-the-art microsensor, stable isotope tracer, and molecular techniques was used to evaluate coupled nitrification-denitrification potentials and community structure of ammonia-oxidizing bacteria in a high yield irrigated rice cropping system in the Philippines, without the use of microcosm incubations.

Methanobacterium aarhusense sp. nov., a novel methanogen isolated from a marine sediment (Aarhus Bay, Denmark).

Strain H2-LR(T), a 5-18 micro m long and 0.7 micro m wide filamentous, mesophilic, moderately halophilic, non-motile hydrogenotrophic methanogen, was isolated from marine sediment of Aarhus Bay, Denmark, 1.7 m below the sediment surface.

Characterization of the marine propionate-degrading, sulfate-reducing bacterium Desulfofaba fastidiosa sp. nov. and reclassification of Desulfomusa hansenii as Desulfofaba hansenii comb. nov.

A rod-shaped, slightly curved sulfate reducer, designated strain P2(T), was isolated from the sulfate-methane transition zone of a marine sediment. Cells were motile by means of a single polar flagellum. The strain reduced sulfate, thiosulfate and sulfite to sulfide and used propionate, lactate and 1-propanol as electron donors.

Enumerating ammonia-oxidizing bacteria in environmental samples using competitive PCR.

Primers targeting part of the ammonia-monooxygenase gene (amoA) have been used to detect and characterize ammonia-oxidizing bacteria (AOB) in different environments. In this study, a quantitative polymerase chain reaction (PCR) technique using a competitive template for the amoA primer pair is described and evaluated. The method is based on addition of an internal standard to the PCR, a competitive template, which is amplified together with the template in the environmental sample.

Influence of different cultivars on populations of ammonia-oxidizing bacteria in the root environment of rice.

Comparisons of the activities and diversities of ammonia-oxidizing bacteria (AOB) in the root environment of different cultivars of rice (Oryza sativa L.) indicated marked differences despite identical environmental conditions during growth. Gross nitrification rates obtained by the 15N dilution technique were significantly higher in a modern variety, IR63087-1-17, than in two traditional varieties.

Denaturing gradient gel electrophoresis (DGGE) approaches to study the diversity of ammonia-oxidizing bacteria.

Denaturing gradient gel electrophoresis (DGGE) of PCR amplicons of the ammonia monooxygenase gene (amoA) was developed and employed to investigate the diversity of ammonia-oxidizing bacteria (AOB) in four different habitats. The results were compared to DGGE of PCR-amplified partial 16S rDNA sequences made with primers specific for ammonia-oxidizing bacteria. Potential problems, such as primer degeneracy and multiple gene copies of the amoA gene, were investigated to evaluate and minimize their possible impact on the outcome of a DGGE analysis.