Low Genetic Differentiation with High Genetic Variability Observed in Common Coastal Starfish Asterina pectinifera around Japan Inferred from Isozyme Analysis

Genetic variability and geographic population structure in population of the common coastal starfish Asterina pectinifera were examined in nine localities around Japan through isozyme analysis. Surveying 28 enzymes by using starch gel electrophoresis, it was found that eight loci controlling seven enzymes were useable as genetic markers. Genetic variability of this species estimated from the 8 loci followed ; the proportion of variant loci ranged from 0.63 to 1.00 with a mean of 0.80, expected average heterozygosity was from 0.176 to 0.208 with a mean of 0.184, and mean number of alleles per locus ranged from 2.5 to 3.8 with a mean of 3.0. The genetic variability of this species was comparatively high among aquatic animals. In order to evaluate genetic differences among the nine localities around Japan, the allelic and genotypic homogeneity tests were carried out and Nei\u27s genetic distance was calculated between every pair of the nine localities. Significant differences among localities showed at only a few loci, but genetic distances were low between any pair of localities. Thus, genetic differentiation has not occurred among localities around Japan in A. pectinifera

Upper bounds on cyclotomic numbers

In this article, we give upper bounds for cyclotomic numbers of order e over a finite field with q elements, where e is a divisor of q-1. In particular, we show that under certain assumptions, cyclotomic numbers are at most $\lceil\frac{k}{2}\rceil$, and the cyclotomic number (0,0) is at most $\lceil\frac{k}{2}\rceil-1$, where k=(q-1)/e. These results are obtained by using a known formula for the determinant of a matrix whose entries are binomial coefficients.Comment: 11 pages, minor revisio

Residual Currents around Asymmetrical Pipes in Oscillatory Flow Fields

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Bisbenzamidine derivative, pentamidine represses DNA damage response through inhibition of histone H2A acetylation

<p>Abstract</p> <p>Background</p> <p>MRE11 is an important nuclease which functions in the end-resection step of homologous recombination (HR) repair of DNA double-strand breaks (DSBs). As MRE11-deficient ATLD cells exhibit hyper radio-sensitivity and impaired DSB repair, MRE11 inhibitors could possibly function as potent radio-sensitizers. Therefore, we investigated whether a bisbenzamidine derivative, pentamidine, which can inhibit endoexonuclease activity, might influence DSB-induced damage responses <it>via </it>inhibition of MRE11.</p> <p>Results</p> <p>We first clarified that pentamidine inhibited MRE11 nuclease activity and also reduced ATM kinase activity in vitro. Pentamidine increased the radio-sensitivity of HeLa cells, suggesting that this compound could possibly influence DNA damage response factors in vivo. Indeed, we found that pentamidine reduced the accumulation of γ-H2AX, NBS1 and phospho-ATM at the sites of DSBs. Furthermore, pentamidine decreased HR activity <it>in vivo</it>. Pentamidine was found to inhibit the acetylation of histone H2A which could contribute both to inhibition of IR-induced focus formation and HR repair. These results suggest that pentamidine might exert its effects by inhibiting histone acetyltransferases. We found that pentamidine repressed the activity of Tip60 acetyltransferase which is known to acetylate histone H2A and that knockdown of Tip60 by siRNA reduced HR activity.</p> <p>Conclusion</p> <p>These results indicate that inhibition of Tip60 as well as hMRE11 nuclease by pentamidine underlies the radiosensitizing effects of this compound making it an excellent sensitizer for radiotherapy or chemotherapy.</p

SO2ガスによるHDDディスク基板の表面汚染と腐食

取得学位：博士(工学)，学位授与番号：博甲第745号，学位授与年月日：平成17年3月22

Intestinal carriage of methicillin-resistant Staphylococcus aureus in nasal MRSA carriers hospitalized in the neonatal intensive care unit

BACKGROUND: The current data regarding the correlation between the methicillin-resistant Staphylococcus aureus (MRSA) clones carried in the nasal cavity and digestive tract are inadequate. METHODS: MRSA strains were isolated from both the feces and nasal swabs of 21 nasal-MRSA carriers ranging from 10 to 104 days of age treated at the neonatal intensive care units of two hospitals. The molecular epidemiological characteristics of the isolates were determined: multilocus sequence types, spa-types, staphylococcal cassette chromosome mec (SCCmec) types, carriage of four exotoxin genes, and genes contained in commercially available kit. RESULTS: The feces of all nasal carriers contained MRSA at levels ranging from 4.0 × 10(2) to 2.8 × 10(8) colony forming units/g feces. The MRSA clones isolated from the feces and the nasal swabs of each patient were the same. Four MRSA clones, clonal complex (CC) 8-SCCmec IVl, CC8-SCCmec IVb, CC1-SCCmec IVa and CC5-SCCmec IIa were identified from 21 patients. All CC8-SCCmec IVl strains and one of three CC5-SCCmec IIa strains carried the toxic shock syndrome toxin gene. CONCLUSIONS: The feces of tested MRSA carriers contained the same MRSA clones as the nasal isolates in considerable amounts, suggesting that more careful attention should be paid for the handling of excrement in the case of newborn babies or infants than that of adults

Induction of Excess Centrosomes in Neural Progenitor Cells during the Development of Radiation-Induced Microcephaly

The embryonic brain is one of the tissues most vulnerable to ionizing radiation. In this study, we showed that ionizing radiation induces apoptosis in the neural progenitors of the mouse cerebral cortex, and that the surviving progenitor cells subsequently develop a considerable amount of supernumerary centrosomes. When mouse embryos at Day 13.5 were exposed to γ-rays, brains sizes were reduced markedly in a dose-dependent manner, and these size reductions persisted until birth. Immunostaining with caspase-3 antibodies showed that apoptosis occurred in 35% and 40% of neural progenitor cells at 4 h after exposure to 1 and 2 Gy, respectively, and this was accompanied by a disruption of the apical layer in which mitotic spindles were positioned in unirradiated mice. At 24 h after 1 Gy irradiation, the apoptotic cells were completely eliminated and proliferation was restored to a level similar to that of unirradiated cells, but numerous spindles were localized outside the apical layer. Similarly, abnormal cytokinesis, which included multipolar division and centrosome clustering, was observed in 19% and 24% of the surviving neural progenitor cells at 48 h after irradiation with 1 and 2 Gy, respectively. Because these cytokinesis aberrations derived from excess centrosomes result in growth delay and mitotic catastrophe-mediated cell elimination, our findings suggest that, in addition to apoptosis at an early stage of radiation exposure, radiation-induced centrosome overduplication could contribute to the depletion of neural progenitors and thereby lead to microcephaly