Importance of starting age for myelotoxicity study in dietary restricted rats

The aim of this study was to prove our hypothesis that adult rats with lowering of body weight gain, rats at 12 weeks of age as an example, are suitable for evaluation of myelotoxicity. Age-related differences between young rats (6-week-old study) and adult rats (12-week-old study) were analyzed in hematological examination values. The data of the young rats were reprinted from our previous report (Miyata et al., 2009) since our hypothesis was verified by comparison with that previous report. Several experimental groups were defined for the 12-week-old study as well as for the 6-week-old study; these included 5-fluorouracil (5-FU) treated groups receiving 12, 15 and 18 mg/kg/day (FU12, FU15 and FU18), pair-feeding groups (R12, R15 and R18 receiving the same amount of food as in the FU12, FU15 and FU18 groups, respectively) and a nontreated control group. Numerous hematologic and bone marrow parameters in the 5-FU treated groups were comparable to those in the corresponding pair-feeding groups in both age studies. Generally, the influences of undernutrition were more apparent in the young rats than in the adult rats. Histopathological examinations showed a decrease in hematopoiesis in the bone marrow in the 5-FU treated and pair-feeding groups. No apparent differences were observed in the decreased hematopoiesis between the 5-FU treated and pair-feeding groups in the 6-week-old study, but a difference between these groups was noted in the 12-week-old study; decreased hematopoiesis was more frequently noted in the 5-FU treated groups. These facts suggest that adult rats are more suitable than young rats for evaluation of 5-FU-induced myelotoxicity.     

Effect of gestational exposure to nonylphenol on the development and fertility of mouse offspring

Nonylphenol (NP), a kind of environmental chemical, is thought to imitate endogenous hormones, inhibit the actions of hormones, and induce reproductive abnormalities. A number of experimental animals, usually rats, have been used to evaluate the potential reproductive toxicity of NP. However, the findings of previous studies were contradictory in some cases. Therefore, we used ICR mice as a biomodel for in utero study of NP. After mating, 8- to 12-week-old females were assigned to four groups (n=8) for subcutaneous injections from day 5 to 20 of gestation. Group I animals received corn oil alone as a control, while the mice of groups II, III and IV received NP at concentrations of 1/1000, 1/100 and 1/10 of the LD(50), respectively. A dose-dependent decrease was observed in terminal body weights of males of the F1 generation; however, a very small negative effect was only found in the females of the NP1/10 group. No significant effect was found on the liver weights of both sexes. The weights of the testis and epididymis were slightly decreased in the NP1/10 group. The NP1/100 treatment increased ovary weight considerably. The uterus weight tended to be increased in the NP treatment groups; however, there were large variations. The gestational exposure of the groups had no significant effect on the rate of pregnancy (94.4-100%) and the number of fetuses per litter (13.6-14.3 males, 12.3-13.7 females) compared with the control group. However, the overall mortality of fetuses/embryos was increased considerably in the NP1/100 (male: 13.9%) and NP1/10 (female: 9.8%) groups. These results suggest that exposure to NP in utero possibly affects the body weight and some reproductive organ weights, but does not influence the potential fertility of the F1 generation.     

Nitric oxide induces apoptosis in bovine luteal cells

We previously showed in in vivo and in vitro studies that nitric oxide (NO) is engaged in luteolysis in cattle. Nitric oxide produced locally in the bovine corpus luteum (CL) inhibits progesterone (P4) synthesis and is suggested to be a component of the luteolytic cascade induced by uterine prostaglandin (PG) F2alpha. In the present study, the molecular mechanisms of NO action during structural luteolysis were studied in cultured bovine luteal cells (Days 15-17 of the estrous cycle). The effects of the NO donor (NONOate; 10(-4)M) on DNA fragmentation, cell viability, P4 production and caspase-3 activity were compared with those of PGF2alpha (10(-6)M). Moreover, mobilization of intracellular calcium [Ca2+]i and gene expressions of Fas-L, Fas, bcl-2, bax, and caspase-3 in the cells were determined by semi-quantitative RT-PCR after NONOate treatment. Caspase-3 activity was examined calorimetrically. Contrary to PGF2alpha NONOate decreased cell viability. DNA fragmentation after NONOate treatment increased by more than with PGF22alpha. NONOate increased mobilization of [Ca2+]i in the cells. Although the NO donor did not affect Fas-L and bcl-2 gene expression, it stimulated Fas and bax mRNA and caspase-3 expression. The ratio of bcl-2 to bax mRNA level decreased in the cells treated with NONOate. Moreover, NONOate stimulated caspase-3 activity more effectively than PGF2alpha. The overall results suggest that NO is a luteolytic factor that plays a crucial role in regulation of the estrous cycle in structural luteolysis by inducing apoptosis of luteal cells in cattle.     

Characteristics of frozen-thawed spermatozoa cryopreserved with different concentrations of glycerol in captive Japanese black bears (Ursus thibetanus japonicus)

Seven mature Japanese black bears were used as semen donors, and a total of 7 semen samples collected from the animals by the electroejaculation method were cryopreserved in liquid nitrogen. Egg yolk-TRIS-citrate-glucose extender was used, and the effects of different final concentrations of glycerol, at 4-12% (v/v), on frozen-thawed spermatozoa were examined. No significant difference was observed in percent motility or percent abnormal morphology of frozen-thawed spermatozoa among the different glycerol concentrations. Percent viability and percent intact acrosomes of spermatozoa cryopreserved with 4 and 6% glycerol were significantly higher than those with 10 and 12% glycerol. These results suggest that a suitable glycerol concentration for freezing Japanese black bear semen within the range tested would be 4-6%.     

Molecular loops in the galactic center: evidence for magnetic flotation

The central few hundred parsecs of the Milky Way host a massive black hole and exhibit very violent gas motion and high temperatures in molecular gas. The origin of these properties has been a mystery for the past four decades. Wide-field imaging of the (12)CO (rotational quantum number J = 1 to 0) 2.6-millimeter spectrum has revealed huge loops of dense molecular gas with strong velocity dispersions in the galactic center. We present a magnetic flotation model to explain that the formation of the loops is due to magnetic buoyancy caused by the Parker instability. The model has the potential to offer a coherent explanation for the origin of the violent motion and extensive heating of the molecular gas in the galactic center.     

Modes of inheritance of two apomixis components,diplospory and parthenogenesis,in Chinese chive (Allium ramosum) revealed by analysis of the segregating population generated by back-crossing between amphimictic and apomictic diploids

To investigate the mode of inheritance of apomixis in Chinese chive, the degrees of diplospory and parthenogenesis were evaluated in F₁ and BC₁ progenies derived from crosses between amphimictic and apomictic diploids (2n = 16, 2x). The F₁ population was generated by crossing three amphimictic diploids 94Mo13, 94Mo49 and 94Mo50 with an apomictic diploid KaD2 and comprised 110 diploids and 773 triploids. All the diploid F₁ plants examined were completely or highly eusporous and completely syngamic. All the triploid F₁ plants examined were highly diplosporous and highly parthenogenetic. KaD2 could not transmit its high level of apomixis via monoploid pollen grains. The BC₁ population, generated by crossing 94Mo49 with apomictic triploids found in the F₁ offspring, exhibited heteroploidy; it comprised haploid, diploid, triploid, tetraploid and various aneuploid individuals. In this generation, clear segregation was observed between diplospory and parthenogenesis. Analysis of the BC₁ population suggests that diplospory and parthenogenesis are each controlled by single dominant genes, D and P, respectively. However, all the BC₁ plants characterized as parthenogenetic were diplosporous. The absence of phenotypically eusporous parthenogenetic plants can be explained by assuming that the presence of diplospory gene is a prerequisite for the parthenogenesis gene expression in Chinese chive.     

Substrate specificity of carp hepatopancreatic cathepsin S for peptides and myofibrillar proteins

SUMMARY: From 250 g of carp hepatopancreas, 0.29 mg of the purified enzyme was obtained. The bond specificity of cathepsin S for α-neoendorphin and neurotensin was ⁶Arg-⁷Lys and ³Tyr-⁴Glu, respectively. The cleavage sites for insulin B-chain were estimated to be the bonds at ³Asn-⁴Gln, ⁶Leu-⁷Cys, ¹²Val-¹³Glu, ¹³Glu-¹⁴Ala, ¹⁶Tyr-¹⁷Leu, ²²Arg-²³Gly, ²⁴Phe-²⁵Phe and ²⁶Tyr-²⁷Thr. P2 position on these peptides were bulky and hydrophobic amino acid residues such as Phe or Leu, small amino acid residues such as Gly, Ala and Val were also accepted in these positions. Regarding the protein substrates, cathepsin S degraded carp α-actinin, actin, tropomyosin and troponins T and I although the proteolyzing speeds were distinct from one another.     

Cryopreservation of Delphinium pollen at –30 °C

Pollen of garden varieties and species of Delphinium that was cryopreserved at –30 ^°C after 3 hours of air drying and storage on silica gel, had high germination and pollen tube growth in vitroeven after 180-day storage. On the other hand, pollen stored at 25 ^°C showed a marked decrease in the germination rate within 10 days. The best in vitro germination of Delphinium pollen was on a 1% water agar containing 15% sucrose and 0.005 to 0.01% boric acid and at 15 to 20 ^°C. Field pollination with the cryopreserved pollen showed higher fruit and seed set than pollination with pollen stored at 25 ^°C, and was not significantly different from fresh pollen. This revised version was published online in August 2006 with corrections to the Cover Date.     

Black tea polyphenols, theaflavins, prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P450 1A1 in cell cultures.

Tea polyphenols have been demonstrated as chemopreventive agents in a number of experimental models. However, less is known about the mechanism of chemoprevention by black tea compared with that of green tea. Some beneficial properties of theaflavins, the black tea polyphenols, were investigated in the present study. Theaflavins showed inhibitory effects on H(2)O(2)- and tert-butyl hydroperoxide (tBuOOH)-induced cytotoxicity (evaluated by tetrazolium bromide reduction), cellular oxidative stress (detected by oxidation of 2', 7'-dichlorofluorescin), and DNA damage (measured by amount of 8-OHdG and comet assay) in rat normal liver epithelium cell RL-34 cell lines. In addition, theaflavins also exhibited suppression of cytochrome P450 1A1 induced by omeprazole in the human hepatoma HepG2 cell line. Furthermore, when HepG2 cells were pretreated with omeprazole to induce CYP1A1, then exposed to benzo[a]pyrene (B[a]P), DNA damage was observed using the comet assay. However, theaflavins could inhibit this DNA damage. These results indicated that theaflavins could prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P450 1A1 in cell cultures.