Contrasting effect of perlecan on adipogenic and osteogenic differentiation of mesenchymal stem cells in vitro

Perlecan, a basement membrane component, shows diverse functions in different organs and tissues. However, the role of perlecan in differentiation of mesenchymal stem cells (MSCs) has been barely investigated. In this study, we examined the effect of perlecan on adipogenic and osteogenic differentiation of MSCs in vitro by adding extrinsic perlecan to culture media or blocking the function of intrinsic perlecan expressed into culture media by differentiating MSCs. Extrinsic perlecan suppressed adipogenic differentiation; however, it promoted osteogenic differentiation. These functions were further confirmed by a study of blocking intrinsic perlecan. Perlecan treated with heparitinase‐I also showed the suppressive effect on adipogenic differentiation. In contrast, the promotive effect on osteogenic differentiation was found to be heparan sulfate‐dependent. Intrinsic perlecan was suggested to be effective at the late stage of adipogenic differentiation by a study of perlecan‐blocking performed at distinct periods, but was suggested to be effective at the early stage of osteogenic differentiation. Our results showed perlecan has contrasting effect on adipogenic and osteogenic differentiation of MSCs due to its diverse actions. Based on these outcomes, we recognized that employing extrinsic perlecan or blocking intrinsic perlecan is effective for regulating adipogenic and osteogenic differentiation of MSCs by restricting its direction.     

The role estrogens play in sex differentiation and sex changes of fish

Using genetically controlled all-female and all-male tilapia (Oreochromis niloticus), the role steroid hormones play in the sex differentiation was analyzed histologically, ultrastructurally, immunohistichemically and experimenntally. The results strongly suggest that endogenous estrogen acts as an ovarian inducer, and that the lack of steroid hormone including androgen is important for testicular differentiation. Moreover, the roles of steroid hormones in protogynous sex change of three-spotted wrasse (Halichoeres trimaculatus) and saddleback wrasse (Tharassoma duperrey) were examined. The results strongly support the hypothesis that the endogenous estrogen plays an important role in protogynous sex change.     

Regulation of steriodogenic enzyme mRNAs in rainbow trout (Oncorhynchus mykiss) ovarian follicles in vitro

The effect of gonadotropins, forskolin and IGF-I on steroidogenic enzyme gene expression and E2 production by the rainbow trout follicle were measured. The results indicate that 3β-HSD gene expression is regulated by gonadotropins partially through the cAMP/PKA mechanism. The effect of IGF-I on P450arom mRNA levels suggests that IGF-I is a major regulator of P450arom gene expression.     

Lunar-related spawning in honeycomb grouper, Epinephelus merra

Lunar-related spawning in honeycomb grouper was investigated by histological and behavioral analyses. Ovarian development and spawning of the fish were related to lunar periodicity. And also the fish migrated to out side of the reef area and spawned for a few days after the full moon.     

Surface disinfection of Pacific threadfin, Polydactylus sexfilis, and amberjack, Seriola rivoliana, eggs

The effects of exposing the eggs of Pacific threadfin and amberjack eggs (AEs) to different concentrations of hydrogen peroxide for 5 min on hatch rate and survival were assessed in a series of experiments using a petri dish model rearing system. Despite significant inter‐batch variation in hatch rate, it was shown that eggs of both species could be safely exposed to up to 11 340 mg L⁻¹ H₂O₂ for 5 min. Exposure to 34 230 mg L⁻¹ H₂O₂ for 5 min was shown to be lethal to AEs at a late stage of development. In two further experiments, it was demonstrated that Pacific threadfin eggs were resistant to all tested concentrations of a range of polyvinylpyrrolidone iodine (PVP‐I) concentrations and contact times (up to 1000 mg L⁻¹ PVP‐I for 10 min). The level of bacteria adhering to the eggs of both species was highly variable. Where eggs were heavily colonized (>10⁴ cfu egg⁻¹), hydrogen peroxide concentrations of at least 11 340 mg L⁻¹, or PVP‐I concentrations higher than 500 mg L⁻¹ for 10 min, were required for effective sterilization. In less colonized batches, rinsing in sterile seawater or exposure to lower (550 mg L⁻¹) concentrations of H₂O₂ was sufficient to result in high apparent levels of surface sterility (<1 cfu egg⁻¹).     

Activity patterns of abalone under experimental conditions

Locomotion behaviour of the abalone, Nordotis discus (Reeve), N. gigantea (Gmelin) and Sulculus aquatilis (Reeve), was observed for 5‐ to 10‐day periods during the early summer and autumn from 1997 to 1999. Before sunset, the animals were individually put beneath each shelter situated on the flat concrete floor of indoor and outdoor tanks. For tracing of the locomotion path, a luminous rod was fixed on the animal's shell. Except for non‐appearance, the locomotion behaviour showed leaving or homing; these ratios against each total observation according to each species were 70.0% and 16.7% in N. discus, 47.1 and 23.5% in N. gigantea and 57.6 and 24.2% in S. aquatilis respectively. Irrespective of species, recurrences to the home were frequently recognized during the locomotion. For the homing behaviour, its critical distance was approximately 1 m from the home. Moonlight did not completely restrain the abalone appearance from the home, though the appearance frequency during the period around the full moon was lowered and in some cases the time of initial appearance was retarded.     

Elevation of lipid peroxide level and production of hydroxy lipids in cultured Hepa-T1 cells by oxidative stressors

ABSTRACT:   In order to investigate the relationships between levels of lipid peroxides (LPO), hydroxy lipids (L-OH) and of antioxidative enzymes in live fish, cultured cells from tilapia liver (Hepa-T1) were treated with oxidative stressors, 2,2'-azobios(2-amidino-propane) dihydrochloride (AAPH) and H₂O₂. By treating with 5 mM AAPH, LPO and L-OH of the cells significantly increased time-dependently. In particular, L-OH increased from 7.6 ± 0.7 to 23.6 ± 1.8 nmol/mg protein after 2 h of treatment, and synchronously the glutathione peroxidase (GPx) activity of the cells increased from 259 ± 106 to 1970 ± 135 mU/mg protein. In the case of H₂O₂, however, no elevation of L-OH was observed. In this case, catalase (CAT) and superoxide dismutase (SOD) activities increased time-dependently. Especially, after 2 h exposure, the CAT activity increased remarkably from 217 ± 21 to 2510 ± 120 mU/mg protein, though the GPx activity did not change significantly. These results suggest that the elevation of the L-OH level is closely associated with the elevation of GPx activity, but not with that of CAT or SOD. However, when vitamin E-enriched Hepa-T1 cells were treated with AAPH and H₂O₂, the production of LPO and L-OH was suppressed significantly. The findings suggest that vitamin E also plays an important role in the levels of the oxidation products in vivo .     

Chromospheric anemone jets as evidence of ubiquitous reconnection

The heating of the solar chromosphere and corona is a long-standing puzzle in solar physics. Hinode observations show the ubiquitous presence of chromospheric anemone jets outside sunspots in active regions. They are typically 3 to 7 arc seconds = 2000 to 5000 kilometers long and 0.2 to 0.4 arc second = 150 to 300 kilometers wide, and their velocity is 10 to 20 kilometers per second. These small jets have an inverted Y-shape, similar to the shape of x-ray anemone jets in the corona. These features imply that magnetic reconnection similar to that in the corona is occurring at a much smaller spatial scale throughout the chromosphere and suggest that the heating of the solar chromosphere and corona may be related to small-scale ubiquitous reconnection.     

Microbial community responsible for the decomposition of rice straw in a paddy field: estimation by phospholipid fatty acid analysis

To estimate the microbial communities responsible for rice straw decomposition in paddy field, phospholipid fatty acid (PLFA) composition of leaf sheaths and blades was analyzed during the decomposition of both residues under upland conditions after harvest and under flooded conditions at the time of transplanting of rice plants. In addition, rice straw that had been placed in the field under upland conditions (November to April) was taken out in spring, and placed again in the same field under flooded conditions at the time of transplanting. High proportions of the branched-chain PLFAs were observed under flooded conditions (June to September); the proportions of straight mono-unsaturated and straight poly-unsaturated PLFAs were high under upland conditions in the winter season for 4 months. The dominant PLFAs in straight mono-unsaturated, straight poly-unsaturated and branched-chain PLFA groups were 18:19, 18:17 and 16:17c, 18:26c and i15:0, i17:0 and ai15:0, respectively, under both upland and flooded conditions. These findings indicated the important roles of Gram-negative bacteria and fungi under upland conditions and of Gram-positive bacteria and anaerobic Gram-negative bacteria under flooded conditions. Cluster analysis of PLFA composition showed the difference of community structure of microbiota in rice straw between upland and flooded conditions. In addition principal component analysis revealed the difference between leaf sheaths and blades under upland conditions and indicated that the content of straight unsaturated PLFAs (sheaths > blades) characterized their community structures.     

Influence of earthworm activity and rice straw application on the soil microbial community structure analyzed by PLFA pattern

The earthworm Pheretima hilgendorfi, one of the most common anecic species in Japan, abounds in soils with applied rice-straw residues. The influences of the worm’s activity and/or those of rice-straw application on the soil microbial community structure were studied using a microcosm approach. Low Humic Andosol was incubated with or without earthworms in a jar for a month after the following treatments: 1) no treatment, 2) chopped rice straw top-dressed on the soil and 3) rice straw incorporated into the soil. The soil NO₃^–-N level increased with the earthworms’ presence even in the soil without rice straw. The soil NH₄⁺-N level was by far the highest in the soil treated with worms and no rice straw. Amounts of total and bacterial PLFAs increased due to the earthworms’ presence when rice straw was incorporated. The proportion of unsaturated fatty acids increased in the earthworm treatment while the saturated fatty acids decreased, suggesting an increase in the Gram-negative bacterial proportion. The results of principal component analysis indicated that the rice straw and the earthworms affected the soil microbial community structure independently. Any direct influence of the PLFAs contained in the worms’ bodies and in the rice straw on the soil’s PLFA profile was thought to be small.