Novel European free-living, non-diazotrophic Bradyrhizobium isolates from contrasting soils that lack nodulation and nitrogen fixation genes - a genome comparison

The slow-growing genus Bradyrhizobium is biologically important in soils, with different representatives found to perform a range of biochemical functions including photosynthesis, induction of root nodules and symbiotic nitrogen fixation and denitrification. Consequently, the role of the genus in soil ecology and biogeochemical transformations is of agricultural and environmental significance. Some isolates of Bradyrhizobium have been shown to be non-symbiotic and do not possess the ability to form nodules. Here we present the genome and gene annotations of two such free-living Bradyrhizobium isolates, named G22 and BF49, from soils with differing long-term management regimes (grassland and bare fallow respectively) in addition to carbon metabolism analysis. These Bradyrhizobium isolates are the first to be isolated and sequenced from European soil and are the first free-living Bradyrhizobium isolates, lacking both nodulation and nitrogen fixation genes, to have their genomes sequenced and assembled from cultured samples. The G22 and BF49 genomes are distinctly different with respect to size and number of genes; the grassland isolate also contains a plasmid. There are also a number of functional differences between these isolates and other published genomes, suggesting that this ubiquitous genus is extremely heterogeneous and has roles within the community not including symbiotic nitrogen fixation

Effect of fixation temperature on flow cytometric measurement of intracellular antibody content of hybridomas during batch culture

In order to investigate the effect of fixation temperature on flow cytometric measurement of intracellular antibody content of hybridoma cells, cells in different growth stages during a batch culture were fixed and stored at 4 and -20 °C, respectively. Flow cytometric analysis indicates that both fixation temperatures can be used in monitoring the changes in intracellular antibody content of the cells during a batch culture. However, it is better to fix and store the cells at -20 °C than 4 °C with regard to preservation of intracellular antibody and storage stability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42491/1/10542_2004_Article_BF00150897.pd

Flow effects on the viability and lysis of suspended mammalian cells

A mouse myeloma cell line growing in suspension was subjected intermittently to flow through a sudden contraction and turbulent flow in a capillary tube. The probability of lysis per pass through the capillary tube increased with average wall shear stress level and with residence time per pass in the tube. Lysis was first observed at a threshold average wall shear stress level of 1800 dyn/cm^2. Although the flow caused lysis, it had no effect on cell viability

Catabolites produced by the deacetylation of hexamethylenebisacetamide play a key role in murine erythroleukaemic-cell differentiation.

N-Acetyl-1,6-diaminohexane and 1,6-diaminohexane, formed by deacetylation of the inducer hexamethylenebisacetamide (HMBA), are shown to accumulate rapidly inside murine erythroleukaemic cells. The appearance of these molecules preceded the differentiation-associated changes in intracellular polyamines. A quantitative relationship was observed between the accumulation of these molecules and the changes in intracellular polyamines. In the absence of HMBA, exogenous N-acetyl-1,6-diaminohexane was able not only to cause changes in polyamine biosynthesis, but also to induce the complete differentiation process. These results imply that these catabolites of HMBA are directly responsible for the changes in polyamine biosynthesis and probably also for initiating other events regulatory for the differentiation of these cells