\u3cem\u3eRhizobium phaseoli\u3c/em\u3e Symbiotic Mutants with Transposon Tn5 Insertions

Rhizobium phaseoli CFN42 DNA was mutated by random insertion of Tn5 from suicide plasmid pJB4JI to obtain independently arising strains that were defective in symbiosis with Phaseolus vulgaris but grew normally outside the plant. When these mutants were incubated with the plant, one did not initiate visible nodule tissue (Nod-), seven led to slow nodule development (Ndv), and two led to superficially normal early nodule development but lacked symbiotic nitrogenase activity (Sna-). The Nod- mutant lacked the large transmissible indigenous plasmid pCFN42d that has homology to Klebsiella pneumoniae nitrogenase (nif) genes. The other mutants had normal plasmid content. In the two Sna- mutants and one Ndv mutant, Tn5 had inserted into plasmid pCFN42d outside the region of nif homology. The insertions of the other Ndv mutants were apparently in the chromosome. They were not in plasmids detected on agarose gels, and, in contrast to insertions on indigenous plasmids, they were transmitted in crosses to wild-type strain CFN42 at the same frequency as auxotrophic markers and with the same enhancement of transmission by conjugation plasmid R68.45. In these Ndv mutants the Tn5 insertions were the same as or very closely linked to mutations causing the Ndv phenotype. However, in two mutants with Tn5 insertions on plasmid pCFN42d, an additional mutation on the same plasmid, rather than Tn5, was responsible for the Sna- or Ndv phenotype. When plasmid pJB4JI was transferred to two other R. phaseoli strains, analysis of symbiotic mutants was complicated by Tn5-containing deleted forms of pJB4JI that were stably maintained

Absolute calibration of GafChromic film for very high flux laser driven ion beams.

We report on the calibration of GafChromic HD-v2 radiochromic film in the extremely high dose regime up to 100 kGy together with very high dose rates up to 7 × 1011 Gy/s. The absolute calibration was done with nanosecond ion bunches at the Neutralized Drift Compression Experiment II particle accelerator at Lawrence Berkeley National Laboratory (LBNL) and covers a broad dose dynamic range over three orders of magnitude. We then applied the resulting calibration curve to calibrate a laser driven ion experiment performed on the BELLA petawatt laser facility at LBNL. Here, we reconstructed the spatial and energy resolved distributions of the laser-accelerated proton beams. The resulting proton distribution is in fair agreement with the spectrum that was measured with a Thomson spectrometer in combination with a microchannel plate detector

Effect of Supplementing Grass Silage with Incremental Levels of Water Soluble Carbohydrate on in Vitro Rumen Microbial Growth and N Use Efficiency

The efficiency of utilisation of N for milk production in dairy cows is often less than 25% and a shortfall in readily available carbohydrate to provide substrate for microbial growth is often cited as a potential problem. Grasses bred for their high water soluble carbohydrate (WSC) content have potential to address this issue but there is limited information on the level of sugar required to optimise rumen microbial growth efficiency. The objective of this experiment was to examine the effect of different concentrations of WSC on the efficiency of use of grass silage N under in vitro conditions

The Effect of Dry Matter Content and Inoculation with Lactic Acid Bacteria on the Residual Water Soluble Carbohydrate Content of Silages Prepared from a High Sugar Grass Cultivar

The introduction of new perennial ryegrass cultivars bred for high water soluble carbohydrate (WSC) content has created opportunities for improving the quality of grass silage, by not only providing adequate WSC for a good fermentation, but also sufficient to leave a higher residual level of WSC in the mature silage. High WSC silages have the potential to provide readily available energy during the early stages of rumen fermentation to balance energy and nitrogen supply and optimise rumen microbial growth. (Merry et al. 2002). The aim was to examine the effect of wilting and silage inoculants on the residual WSC content of grass silage

Cortical Network for Gaze Control in Humans Revealed Using Multimodal MRI

Functional magnetic resonance imaging (fMRI) techniques allow definition of cortical nodes that are presumed to be components of large-scale distributed brain networks involved in cognitive processes. However, very few investigations examine whether such functionally defined areas are in fact structurally connected. Here, we used combined fMRI and diffusion MRI-based tractography to define the cortical network involved in saccadic eye movement control in humans. The results of this multimodal imaging approach demonstrate white matter pathways connecting the frontal eye fields and supplementary eye fields, consistent with the known connectivity of these regions in macaque monkeys. Importantly, however, these connections appeared to be more prominent in the right hemisphere of humans. In addition, there was evidence of a dorsal frontoparietal pathway connecting the frontal eye field and the inferior parietal lobe, also right hemisphere dominant, consistent with specialization of the right hemisphere for directed attention in humans. These findings demonstrate the utility and potential of using multimodal imaging techniques to define large-scale distributed brain networks, including those that demonstrate known hemispheric asymmetries in human