Essential contribution of germline-encoded lysine residues in Jgamma1.2 segment to the recognition of nonpeptide antigens by human gammadelta T cells.

Human gammadelta T cells display unique repertoires of Ag specificities largely imposed by selective usages of distinct Vgamma and Vdelta genes. Among them, Vgamma2/Vdelta2(+) T cells predominate in the circulation of healthy adults and respond to various microbial small molecular mass nonpeptide Ags. The present results indicate that the primary Vgamma2/Vdelta2(+) T cells stimulated with the distinct groups of nonpeptide Ags, including monoethyl pyrophosphate, isobutyl amine, and aminobisphosphonate, invariably exhibit Jgamma1.2 in the Vgamma2(+) TCR-gamma chains. Gene transfer studies revealed that most of the randomly cloned Vgamma2/Jgamma1.2(+) TCR-gamma genes bearing diverse Vgamma/Jgamma junctional sequences could confer the responsiveness to all these nonpeptide Ags, while none of the Vgamma2/Jgamma1.1(+) or Vgamma2/Jgamma1.3(+) TCR-gamma genes could do so. Furthermore, mutation of the lysine residues encoded by the Jgamma1.2 gene, which are unique in human Jgamma1.2 and absent in other human or mouse Jgamma segments, completely abrogated the responsiveness to all the nonpeptide Ags without affecting the response to anti-CD3 mAb. These results strongly suggested that the positively charged lysine residues in the TCR-gamma chain CDR3 region encoded by the germline Jgamma1.2 gene play a key role in the recognition of diverse small molecular mass nonpeptide Ags.     

Cleavage of Disulfide Bonds of Wheat Glutenin by Mercuric Chloride

The dissociation of wheat glutenin into subunits was observed by treatment with a small amount of mercuric chloride under moderate conditions, suggesting that the cleavage of inter-polypeptide chain disulfide bonds in the glutenin might occur. The dissociation into the subunits was examined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The electrophoretic patterns of the glutenin treated with mercuric chloride were essentially similar to those of the glutenin treated with 2-mercaptoethanol. Silver nitrate also had the same effects as mercuric chloride, and p-chloromercuribenzoate and N-ethylmaleimide showed no effect on the dissociation of the glutenin. Complete dissociation was achieved when the glutenin solution containing 0.5% SDS and 0.01 m phosphate buffer (pH 7.0) was incubated with 10^?3 m mercuric chloride (about four moles per mole of disulfide groups) at 30°C for 20 hr. Partial dissociation was also observed after 30 min incubation. Increasing temperature and SDS concentration promoted the rate of the dissociation of the glutenin by mercuric chloride.     

Origin of mitotic cells of the chorionic villi in direct chromosome analysis

Summary The origin of mitotic cells was investigated histologically in chorionic tissue, metaphase plates of which were used for direct cytogenetic study. Mitotic figures were often observed in the Langhans' cell layers, but absolutely none were seen in the syncytium and stromal cells.     

3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole induces apoptosis and necrosis with activation of different caspases in rat splenocytes

A dietary carcinogen, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) at 20 microM activates caspase-3-like proteases as an apoptotic marker in rat splenocytes. The present study demonstrated 100 microM Trp-P-1 induced necrosis with activation of caspase-3-like proteases. The activation in necrosis and apoptosis resulted from the activation of caspase-9 and caspase-8, respectively. Thus, Trp-P-1 induces apoptosis and necrosis with the activation of different caspases.     

Dietary antioxidants fail in protection against oxidative genetic damage in in vitro evaluation

Carcinogenesis is believed to be induced through the oxidative damage of DNA, and antioxidants are expected to suppress it. So, the polyphenolic antioxidants in daily foods were investigated to see whether they protect against genetic damage by active oxygen. In the evaluation, we used a bioassay and a chemical determination, a Salmonella mutagenicity test for mutation by a N-hydroxyl radical from one of the dietary carcinogens 3-amino-1-methyl-5H-pyrido[4,3-b]indole and the formation of 8-hydroxyl (8-OHdG) from 2'-deoxyguanosine (2'-dG) in a Fenton OH-radical generating system. Thirty-one antioxidants including flavonoids were compared in terms of radical-trapping activity with bacterial DNA and 2'-dG. Antioxidants inhibited the mutation but the IC50 values were in the mM order. Against 8-OHdG formation, only alpha-tocopherol had a suppressive effect with an IC50 of 1.5 microM. Thus, except alpha-tocopherol, the dietary antioxidants did not scavenge the biological radicals faster than bacterial DNA and intact 2'-dG, indicating that they failed to prevent oxidative gene damage and probably carcinogenesis.     

Physical interaction between Tbx6 and mespb is indispensable for the activation of bowline expression during Xenopus somitogenesis

Crk is a member of a family of adaptor proteins that are involved in intracellular signal pathways altering cell adhesion, proliferation, and migration. Increased expression of Crk has been described in lung cancer and associated with increased tumor invasiveness. MicroRNAs (miRNAs) are a family of small non-coding RNAs (approximately 21–25 nt long) that are capable of targeting genes for either degradation of mRNA or inhibition of translation. Crk is a predicted putative target gene for miR-126. Over-expression of miR126 in a lung cancer cell line resulted in a decrease in Crk protein without any alteration in the associated mRNA. These lung cancer cells exhibit a decrease in adhesion, migration, and invasion. Decreased cancer cell invasion was also evident following targeted knockdown of Crk. MiR-126 alters lung cancer cell phenotype by inhibiting adhesion, migration, and invasion and the effects on invasion may be partially mediated through Crk regulation.