Incorporation of heavy metals by the mud snail,Cipangopaludina chinensis malleata Reeve,in submerged paddy soil treated with composted sewage sludge

Summary The biomass of newborn snails was higher in paddy soil without rice plants than in the soil with rice plants. There was an inverse correlation between shell width and concentratins of Zn and Cu in snail flesh. The Zn and Cu concentrations in snail flesh were extremely high compared with those in the paddy soil surrounding the snails, possibly because snails ingest sludge, one of the main components of the composts. These results suggest that this type of snail may be used to eliminate Zn and Cu from paddy soil when composted sewage sludge has been applied.     

Induction of superovulation by immunoneutralization of endogenous inhibin in immature rats

The effects of passive immunoneutralization of endogenous inhibin on ovulation rate in immature rats were investigated. Efficiency of superovulation on production of fertilized oocytes was compared between the inhibin antiserum (inhibin-AS) and equine chorionic gonadotropin (eCG) protocols. Immature female Wistar strain rats were superovulated with a single injection of 100-200 microl inhibin-AS, with and without an injection of human chorionic gonadotropin (hCG). A total of 77.8% of the 26-30-day-old rats treated with a single injection of 100-200 microl inhibin-AS ovulated 72 h after treatment, while rats given normal goat serum (NGS; 200 microl) did not ovulate. At 28 days of age, all of the inhibin-AS treated rats ovulated when additional hCG treatment was given, whereas the number of ovulated oocytes was not affected. The number of ovulated oocytes in the inhibin-AS-hCG treated groups was significantly higher than that of the NGS-hCG treated group. In addition, plasma concentrations of FSH in the inhibin-AS-hCG treated group significantly increased compared with the NGS treated group. While the percentage of mated rats in the 200 microl inhibin-AS-hCG treated group was significantly lower than that of the 15 IU eCG-hCG treated group, the fertilization rate was comparable between the two groups. The number of fertilized oocytes in the 200 microl inhibin-AS-hCG treated group was significantly higher in comparison with the 15 IU eCG-hCG treated group. These results suggest that immunoneutralization of endogenous inhibin could be a reliable method for induction of superovulation to collect a large number of normally fertilized oocytes in immature rats.     

Effects of bud scales and gibberellins on dormancy of in vitro cultured Japanese pear leaf buds

Leaf buds of Japanese pear were collected in early June and early November and regarded as summer and winter dormant buds, respectively. Bud explants with and without scales were prepared from each of them, and cultured in vitro for 75 days at 25°C with 14 h photoperiod, on a medium either without growth regulators, or supplied with BA and GAs (GA₃ and GA₄₊₇), singly or in combination.When either BA or GA₄₊₇ was contained in the medium, bud expansion occurred. Thereafter, summer dormant buds grew into shoots in the presence of BA, while winter dormant buds, although they swelled profusely, remained in a rosette. In the presence of BA, GA₄₊₇ markedly stimulated shoot elongation of summer dormant buds, but GA₃ did not. In winter dormant buds, GA₄₊₇ not only failed to stimulate shoot elongation, but also interfered with the BA-induced swelling described above.The presence of bud scales delayed expansion of summer dormant buds, while it had little effect on winter dormant buds. The delaying effect of scales on expansion of summer buds was effectively removed by application of GA₄₊₇ to the medium.     

Antigenic differences between H5N1 human influenza viruses isolated in 1997 and 2003

To assess whether the antigenic properties of H5 hemagglutinin (HA) change over time due to antigenic drift, we produced a panel of monoclonal antibodies (mAbs) against the HA of the index H5N1 human influenza A virus, A/Hong Kong/156/97. By immunizing mice with a plasmid expressing this HA and boosting the initial immunization with cell lysates transfected with the plasmid, a total of six hybridomas producing HA-specific mAbs were established: four to the HA1 subunit with hemadsorption-inhibiting activity and two to the HA2 subunit. None of the mAbs to HA1 could bind to the HA of a recent human isolate, A/Hong Kong/213/2003, indicating that there are substantial antigenic differences between the H5N1 human influenza virus isolated in 1997 and that isolated in 2003.     

Glucose uptake activity in murine red blood cells infected with Babesia microti and Babesia rodhaini

The glucose uptake activity in Babesia rodhaini and B. microti - infected red blood cell (IRBC) was investigated in mice using 2-deoxy-D-glucose (2DOG) and L-glucose (L-Glc), a non-metabolizable analogue of D-glucose and non-incorporative glucose to non-infected RBC (NRBC), respectively. The uptake activities of both DOG and L-Glc were higher in IRBCs than those in NRBC. The concentration dependent uptake of 2DOG and L-Glc in both IRBC revealed a linear curve, indicating non-transporter mediated uptake. In addition, B. microti IRBC showed higher 2DOG uptake than B. rodhaini IRBC, whereas no difference was observed in L-Glc uptake. These results indicated that some new glucose uptake system, at least two systems, developed in both IRBC. The new systems were sodium independent, non-competitive to L-Glc, and sensitive to temperature. One of two systems had no kinetical difference between B. rodhaini and B. microti IRBC, however another one might have higher uptake activity in B. microti IRBC compared to that in B. rodhaini IRBC.     

Localization of endothelin receptor subtype-A in the testis of rats, dogs, and monkeys

In order to evaluate the physiological roles of the testicular endothelin (Edn) signaling via Edn receptor subtype-A (Ednra) in mammals, the localization of Ednra was investigated by in situ hybridization and immunohistochemistry in the testis of rats, dogs, and monkeys. For in situ hybridization, a rat Ednra RNA probe which is highly homologous to the subcloned canine and monkey Ednra (88.7% and 87.9% identical, respectively) was used. Both Ednra mRNA and protein were detected in interstitial cells and cells in the basal compartment of the seminiferous tubules, mainly Sertoli cells, as well as spermatogonia and some early spermatocytes, but not spermatids. The localization pattern of Ednra was exhibited in a same manner among species, indicating that the physiological role of Edn signaling throughout Ednra was maintained in the mammalian testis.     

Changes in allergenicity and digestibility of squid tropomyosin during the Maillard reaction with ribose

The effect of the Maillard reaction on the allergenicity of squid tropomyosin (TM) was investigated. When TM was reacted with ribose (TM-ribose), its human-specific IgE-binding ability decreased markedly and alpha-chymotryptic digestibility of TM was also altered at the early stage of the Maillard reaction. On the other hand, the modification of the lysine residues in TM using 2,4,6-trinitrobenzenesulfonic acid had no effect on the allergenicity and alpha-chymotryptic digestibility of TM. Therefore, the structural change in TM induced by the Maillard reaction would cause the reduction of the allergenicity, rather than the block of lysine residues. Although peptic digestion diminished the specific IgE-binding ability of TM, the reduction of the allergenicity by the Maillard reaction remained after peptic digestion. These results suggest that hypersensitive reaction of TM-ribose in the human body might be lower than that of native TM.