L-Glutamate production by lysozyme-sensitive Corynebacterium glutamicum ltsA mutant strains

BACKGROUND: A non-pathogenic species of coryneform bacteria, Corynebacterium glutamicum, was originally isolated as an L-glutamate producing bacterium and is now used for fermentative production of various amino acids. A mutation in the C. glutamicum ltsA gene caused susceptibility to lysozyme, temperature-sensitive growth, and L-glutamate production. RESULTS: The characteristics of eight lysozyme-sensitive mutants which had been isolated after N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis were examined. Complementation analysis with the cloned wild-type ltsA gene and DNA sequencing of the ItsA region revealed that four mutants had a mutation in the ltsA gene. Among them, two mutants showed temperature-sensitive growth and overproduced L-glutamate at higher temperatures, as well as the previously reported ltsA mutant. Other two showed temperature-resistant growth: one missense mutant produced L-glutamate to some extent but the other nonsense mutant did not. These two mutants remained temperature-resistant in spite of introduction of ltsA::kan mutation that causes temperature-sensitive growth in the wild-type background. CONCLUSIONS: These results indicate that a defect caused by the ltsA mutations is responsible for temperature-sensitive growth and L-glutamate overproduction by C. glutamicum. The two temperature-resistant mutants seem to carry suppressor mutations that rendered cells temperature-resistance and abolished L-glutamate overproduction

Effects of 8-week Nonlinear Periodized Training Program on Physical Fitness and Contributors of Functional Knee Joint Stability in 101st Division Army Soldiers

Army soldiers engage in various types of vigorous physical fitness training daily and unintentional musculoskeletal injuries are quite common. Based on previous research, training principles, and theories, a training program was developed to target components of physical fitness and improve neuromuscular and biomechanical factors that are important to knee joint stability. The purpose of this study was to evaluate the effects of an 8-week nonlinear periodized training program on physical fitness and contributors of functional knee joint stability in 101st Division Army soldiers.Due to the timing of the study, the duration of this training overlapped with the soldiers' deployment preparation schedule. As a result, of 52 soldiers who were initially enrolled (28 in the experimental group and 24 in the control group), only 26 soldiers completed the study (23 in the experimental group and 13 in the control group). Knee and hip strength, knee joint rate of force development, knee proprioception, and knee and hip neuromuscular and biomechanical characteristics during a stop-jump and a drop-jump task were measured before and after the intervention.There were no statistically significant findings for any dependent variables. High attrition rate and the lack of training exposure were the confounding factors for this study. Future studies must consider soldiers' training/deployment schedules to avoid those confounding factors and should monitor the daily training exposure and types of training for the control group

Comparison of DNA methylation levels of repetitive loci during bovine development

<p> Abstract</p> <p>Background</p> <p>DNA methylation of cytosine residues in CpG dinucleotide controls gene expression and dramatically changes during development. Its pattern is disrupted in cloned animals suggesting incomplete reprogramming during somatic cell nuclear transfer (the first reprogramming). However, the second reprogramming occurs in the germ cells and epigenetic errors in somatic cells of cloned animals should be erased. To analyze the DNA methylation changes on the spermatogenesis of bulls, we measured DNA methylation levels of three repetitive elements in blastocysts, blood and sperm.</p> <p>Methods</p> <p>DNA from PBLs (peripheral blood leukocytes), sperm and individual IVF (<it>in vitro</it> fertilized) and parthenogenetic blastocysts was isolated and bisulfite converted. Three repetitive elements; Satellite I, Satellite II and <it>art2</it> sequences were amplified by PCR with specific pairs of primers. The PCR product was then cut by restriction enzymes and analyzed by agarose gel electrophoresis for determining the DNA methylation levels.</p> <p>Results</p> <p>Both Satellite I and Satellite II sequences were highly methylated in PBLs, whereas hypo-methylated in sperm and blastocysts. The <it>art2</it> sequence was half methylated both in PBLs and sperm but less methylated in blastocysts. There was no difference in DNA methylation levels between IVF and parthenogenetic blastocysts.</p> <p>Conclusions</p> <p>These results suggest that there is a dynamic change of DNA methylation during embryonic development and spermatogenesis in cattle. Satellite I and Satellite II regions are methylated during embryogenesis and then de-methylated during spermatogenesis. However, <it>art2</it> sequences are not de-methylated during spermatogenesis, suggesting that this region is not reprogrammed during germ cell development. These results show dynamic changes of DNA methylation levels during bovine embryogenesis, especially genome-wide reprogramming in germ cells.</p

Nuclear Magnetic Relaxation Times of Mn⁵⁵ in Dilute MnFe Alloys

Nuclear magnetic relaxation times (T₁ and T₂) were measured in dilute MnFe alloys. The relaxation processes are effected by the Mn-impurity and related by the functions with impurity concentrations.Article信州大学理学部紀要 10(2): 81-84(1976)departmental bulletin pape

In Vitro Development Potentiality of Expanded Bovine Blastocysts Subsequent to Cryotop Vitrification

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New Constraints on Radiative Decay of Long-Lived Particles in Big Bang Nucleosynthesis with New 4^4He Photodisintegration Data

A recent measurement of $^4$He photodisintegration reactions, $^4$He($\gamma$,$p$)$^3$H and $^4$He($\gamma$,$n$)$^3$He with laser-Compton photons shows smaller cross sections than those estimated by other previous experiments at $E_\gamma \lesssim 30$ MeV. We study big-bang nucleosynthesis with the radiative particle decay using the new photodisintegration cross sections of $^4$He as well as previous data. The sensitivity of the yields of all light elements D, T, $^3$He, $^4$He, $^6$Li, $^7$Li and $^7$Be to the cross sections is investigated. The change of the cross sections has an influence on the non-thermal yields of D, $^3$He and $^4$He. On the other hand, the non-thermal $^6$Li production is not sensitive to the change of the cross sections at this low energy, since the non-thermal secondary synthesis of $^6$Li needs energetic photons of $E_\gamma \gtrsim 50$ MeV. The non-thermal nucleosynthesis triggered by the radiative particle decay is one of candidates of the production mechanism of $^6$Li observed in metal-poor halo stars (MPHSs). In the parameter region of the radiative particle lifetime and the emitted photon energy which satisfies the $^6$Li production above the abundance level observed in MPHSs, the change of the photodisintegration cross sections at $E_\gamma \lesssim 30$ MeV as measured in the recent experiment leads to $\sim 10$% reduction of resulting $^3$He abundance, whereas the $^6$Li abundance does not change for this change of the cross sections of $^4$He($\gamma$,$p$)$^3$H and $^4$He($\gamma$,$n$)$^3$He. The $^6$Li abundance, however, could show a sizable change and therefore the future precise measurement of the cross sections at high energy $E_\gamma \gtrsim$ 50 MeV is highly required.Comment: 10 pages, 7 figures, conclusion not changed, to be published in PR