Follicle selection in cyclic guinea pigs with active immunization against inhibin alpha-subunit

Experiments were conducted to elucidate the mechanisms of active immunization against inhibin on ovarian follicular development and selection in guinea pigs. Estrous cycle was synchronized in experimental guinea pigs by implanting progesterone containing tubes. Antibodies that bound 125I-labeled bovine inhibin were produced by all guinea pigs receiving the inhibin vaccine (recombinant ovine alpha-subunit in oil emulsion) without any effects on duration of the estrous cycle. Active immunization against inhibin increased the plasma concentrations of progesterone during the luteal phase and the plasma concentrations of estradiol but failed to increase the plasma concentration of follicle-stimulating hormone (FSH) during preovulatory period. The treatment also increased the number of corpora lutea (from 1.3+/-0.3 to 7.0+/-1.6 per each ovary), and preovulatory sized follicles (from 1.8+/-0.6 to 7.0+/-1.6 per each ovary), and follicles stained positively for inhibin alpha-subunit (from 2.3+/-0.5 to 6.3+/-1.3 per each ovary) significantly. The results indicate that active immunization against inhibin enhances ovulation rate by affecting the follicle selection and only dominant follicle can be stained for inhibin alpha-subunit in guinea pigs. This study is firstly to provide direct evidence that inhibins play important role in follicle selections in guinea pigs.     

Structural features of the 26S proteasome complex isolated from rat testis and sperm tail

We have previously cloned a cDNA encoding TBP-1, a protein present in the rat spermatid manchette and outer dense fibers of the developing sperm. TBP-1 contains a heptad repeat of six-leucine zipper fingers at the amino terminus and highly conserved ATPase and DNA/RNA helicase motifs toward the carboxyl terminus. TBP-1 is one of the 20 subunits forming the 19S regulatory complex of the 26S proteasome, an ATP-dependent multisubunit protease found in most eukaryotic cells. We now report the isolation of the 26S proteasome from rat testis and sperm tail and its visualization by whole-mount electron microscopy using negative staining. The 26S proteasome from rat testis was fractionated by Sephacryl S-400/Mono-Q chromatography using homogenates suspended in a 10% glycerol-supplemented buffer. Chromatographic fractions were analyzed by immunoblotting using a specific anti-TBP-1 serum. During the purification of Sak57, a keratin filament present in outer dense fibers from epididymal sperm, we detected a substantial amount of 26S proteasomes. Intact 26S proteasomes from rat testis display a rod-shaped particles about 45 nm in length and 11-17 nm in diameter. Each particle consists of a 20S barrel-shaped component formed by four rings (alphabetabetaalpha), capped by two polar 19S regulatory complexes, each identified by an element known as the "Chinese dragon head motif". TBP-1 is an ATPase-containing subunit of the 19S regulatory cap. Rat sperm preparations displayed both dissociated 26S proteasomes and Sak57 filaments. We hypothesize that 26S proteasomes in the perinuclear-arranged manchette are in a suitable location for recognition, sequestration, and degradation of accumulating ubiquitin-conjugated somatic and transient testis-specific histones during spermiogenesis. In the sperm tail, the 26S proteasome may have a role in the remodeling of the outer dense fibers and other tail components during epididymal transit.     

Accelerated evolution of the ASPM gene controlling brain size begins prior to human brain expansion

Primary microcephaly (MCPH) is a neurodevelopmental disorder characterized by global reduction in cerebral cortical volume. The microcephalic brain has a volume comparable to that of early hominids, raising the possibility that some MCPH genes may have been evolutionary targets in the expansion of the cerebral cortex in mammals and especially primates. Mutations in ASPM, which encodes the human homologue of a fly protein essential for spindle function, are the most common known cause of MCPH. Here we have isolated large genomic clones containing the complete ASPM gene, including promoter regions and introns, from chimpanzee, gorilla, orangutan, and rhesus macaque by transformation-associated recombination cloning in yeast. We have sequenced these clones and show that whereas much of the sequence of ASPM is substantially conserved among primates, specific segments are subject to high Ka/Ks ratios (nonsynonymous/synonymous DNA changes) consistent with strong positive selection for evolutionary change. The ASPM gene sequence shows accelerated evolution in the African hominoid clade, and this precedes hominid brain expansion by several million years. Gorilla and human lineages show particularly accelerated evolution in the IQ domain of ASPM. Moreover, ASPM regions under positive selection in primates are also the most highly diverged regions between primates and nonprimate mammals. We report the first direct application of TAR cloning technology to the study of human evolution. Our data suggest that evolutionary selection of specific segments of the ASPM sequence strongly relates to differences in cerebral cortical size.     

VEGF can act as vascular permeability factor in the hepatic sinusoids through upregulation of porosity of endothelial cells

VEGF is shown to be a vascular permeability factor (VPF) as well as a growth stimulatory factor on endothelial cells. In the hepatic sinusoids, endothelial cells express flt-1 and KDR/flk-1, receptors for VEGF. These cells, in primary culture, proliferate in response to VEGF stimulation. However, the role of VEGF as VPF in the hepatic sinusoids is to be elucidated. The effect of VEGF on the porosity of sinusoidal endothelial cells was studied. Sinusoidal endothelial cells were isolated from rats and cultured in DMEM containing 10% FCS on plastic dishes coated with type I collagen for 16 and 48 h for morphological examination and cell-number measurement, respectively. When the cells were cultured without VEGF addition, their number was decreased at 48 h compared to that at 16 h. However, the number was unchanged in the cells cultured with VEGF at 10 ng/mL and increased with addition of VEGF at 100 ng/mL. Scanning electron microscopic examination revealed that sieve-plate appearance of the cells was impaired in culture with no VEGF addition, but the appearance was maintained in culture with VEGF at 10 ng/mL or more. The cells cultured with VEGF at 100 ng/mL showed significantly increased number and size of pores compared to the cells cultured with VEGF at 10 ng/mL, suggesting that sinusoidal endothelial cells proliferating in response to VEGF may increase their porosity. It is concluded that VEGF can act as VPF in the hepatic sinusoids through regulation of endothelial cell porosity.     

Experimental study on convective heat transfer coefficient of the human body

1. 1. The convective heat transfer coefficient of the human body is essential to predict convective heat loss from the body.

2. 2. The object of this paper is to calculate the convective heat transfer coefficient of the human body using heat flow meters and to estimate the thermally equivalent sphere and cylinder to the human body.

3. 3. The experimental formulae of the convective heat transfer coefficient for the whole body were obtained by regression analysis for natural, forced and mixed convection.

4. 4. Diameters of the thermally equivalent sphere and cylinder of the human body were calculated as 12.9 and 12.2 cm, respectively.

Assessing the status of three mangrove species restored by the local community in the cyclone-affected area of the Ayeyarwady Delta,Myanmar

This paper assesses the extent of success and failure of mangrove plantations in Myanmar, restored by local people with the help of foresters under a community forestry program initiated in 1995. The species of these restored plantations are Avicennia officinalis, Avicennia marina and Heritiera fomes, each of which was restored on two plots, one on low and one on high ground, yielding a total of six plots. These plots have been continuously monitored in order to investigate survival and growth rates. The plots were established on abandoned land that had been previously used for paddy cultivation. Cyclone Nargis hit these plantations during the monitoring period, at the beginning of May, 2008. As a consequence, the survival rates of A. officinalis on low ground and A. marina on high ground declined slightly, but the overall affect was not severe. Excluding individuals affected by the cyclone, height and diameter growth of A. officinalis and A. marina were significantly higher on low ground than on high ground, i.e. on sites thought to be consistently similar to the natural habitats of these species. Contrary to these two Avicennia species, the height growth of H. fomes was higher on high ground than on low ground; the diameter growth was not significantly different. As the growth of H. fomes was very slow, however, it is still not possible to describe the differences clearly. This study may provide useful guidelines for foresters and local people to establish successful mangrove restorations and to predict production from community-owned mangrove forests.