Similarity of the outer capsid protein VP4 of the Gottfried strain of porcine rotavirus to that of asymptomatic human rotavirus strains.

Genomic segment 4 of the porcine Gottfried strain (serotype 4) of porcine rotavirus, which encodes the outer capsid protein VP4, was sequences, and its deduced amino acid sequence was analyzed. Amino acid homology of the porcine rotavirus VP4 to the corresponding protein of asymptomatic or symptomatic human rotaviruses representing serotypes 1 to 4 ranged from 87.1 to 88.1% for asymptomatic strains and from 77.5 to 77.8% for symptomatic strains. Amino acid homology of the Gottfried strain to simian rhesus rotavirus, simian SA11 virus, bovine Nebraska calf diarrhea virus, and porcine OSU strains ranged from 71.5 to 74.3%. Antigenic similarities of VP4 epitopes between the Gottfried strain and human rotaviruses were detected by a plaque reduction neutralization test with hyperimmune antisera produced against the Gottfried strain or a Gottfried (10 genes) x human DS-1 rotavirus (VP7 gene) reassortant which exhibited serotype 2 neutralization specificity. In addition, a panel of six anti-VP4 monoclonal antibodies capable of neutralizing human rotaviruses belonging to serotype 1, 3, or 4 was able to neutralize the Gottfried strain. These observations suggest that the VP4 outer capsid protein of the Gottfried rotavirus is more closely related to human rotaviruses than to animal rotaviruses.     

Substance-P-like immunoreactive subepithelial nerve plexuses in the labial mucosa of the mouse

Substance P (SP)-like immunoreactivity was examined in the lower labial mucosa of the mouse by using the whole-mount technique. The density and design of subepithelial nerve plexuses containing SP differed depending on portions of the lower labial mucosa.     

The role of 5'-methylthioadenosine on rat calvaria cell differentiation.

The role of 5'-methylthioadenosine (MTA), formed during the process of polyamine biosynthesis, on differentiation of osteoprogenitor cells was assessed by its effects on alkaline phosphatase (ALP) activity, bone nodule formation and osteopontin contents of cultured rat calvaria (RC) cells. These three markers were stimulated by exogenous MTA and were depressed by 5'-difluoromethylthioadenosine (DFMTA), a synthetic inhibitor of MTA phosphorylase, which cleaves MTA to adenine and 5-methylthioribose-1-phosphate. 5-Methylthioribose and 2-keto-4-methylthiobutyrate, metabolites of 5-methylthioribose-1-phosphate, had no effects on ALP activity and bone nodule formation in the presence or absence of DFMTA. On the other hand, adenine enhanced ALP activity, bone nodule formation and osteopontin contents in mineralized nodules and also partially reversed DFMTA-induced inhibition of these three markers. MTA, its metabolites and DFMTA did not affect the growth of RC cells under these culture conditions. These results suggest that adenine formed from MTA is important in the differentiation of RC cells.     

Concentrations of essential elements after repeated administrations of tin and selenium

To study effects of simultaneous administration of tin (Sn) and selenium (Se) on concentrations of several essential elements, mice were injected with either SnCl2 (ip) or Na2SeO3 (sc), alone or both compounds at a daily dose of 5 mumol/kg each for 12 consecutive days. Mice were sacrificed at 20 h after the last injection and concentrations of Sn, Se, Na, Ca, Zn, P, Fe, K, and Mg in the liver, kidney, spleen, pancreas, testis, seminal vesicle, lung, femoral muscle, and femoral bone were determined. In the control mice, Sn and Se concentrations were the highest in bone (0.69 micrograms Sn and 6.93 micrograms Se/g dry wt). Administered Sn was found to accumulate in all organs except the testis. Among the essential elements determined, Na was the most affected in terms of concentration in the organs and Mg was the least affected element in these organs. Among the organs tested, each elemental concentration in the pancreas was most affected. Simultaneous injections of Sn and Se appeared to keep the correlation coefficients between elements similar to those found in the control mice.     

Stereochemical Control in Microbial Reduction. Part 10. Asymmetric Reduction of Alkyl 3-Methyl-2-Oxobutanoate with Immobilized Bakers' Yeast in Hexane

Esters of 3-methyl-2-oxobutanoic acid are reduced with bakers' yeast by three methods: free bakers' yeast in water, immobilized bakers' yeast in water, and immobilized bakers' yeast in hexane. Although (R)-hydroxy esters are obtained in all cases, the enantiomeric excess varies from 3% (reduction of the methyl ester with free bakers' yeast in water) to 93% (reduction of the butyl ester with immobilized bakers' yeast in hexane) depending on the structure of substrate and on the reaction conditions. The mechanism of the present stereochemical control is discussed.     

A Drosophila receptor-type tyrosine kinase (DFR1) acts as a fibroblast growth factor receptor in Xenopus embryos

Members of the fibroblast growth factor (FGF) family play important roles in various developmental processes in vertebrates. Since two genes closely related to the vertebrate FGF receptor (FGFR) genes DFR1 and DFR2/breathless have already been reported in Drosophila , the existence of a Drosophila FGF has been predicted. In the present study, we examined whether DFR1 is functionally interchangeable with a vertebrate FGFR in the Xenopus system. First, we found that the expression of DFR1 promoted Ca²⁺ efflux in response to human basic (b)FGF in Xenopus oocytes, whereas the coexpression of a dominant negative form of DFR1 (ΔDFR1) with a chick FGFR1/cek1 inhibited promotion of Ca²⁺ efflux induced by the expression of cek1 in the oocyte. Second, the expression of ΔDFR1 was observed to induce a defect in the posterior structure of the Xenopus embryo at stage 30, as observed with a dominant negative form of cek1 (Δcek1). Third, we found that the expression of ΔDFR1 inhibited the expression of FGF-regulated genes such as Xbra, Xnot , and Xshh in Xenopus embryos at stage 11, while the coexpression of DFR1 with ΔDFR1 could rescue the inhibited expression of FGF-regulated genes. These results indicate that DFR1 acts as an FGFR in Xenopus embryos and that an FGF is likely to exist in Drosophila .     

Preparation of biologically active Ascaris suum mitochondrial tRNAMet with a TV-replacement loop by ligation of chemically synthesized RNA fragments.

Ascaris suum mitochondrial tRNA Met lacking the entire T stem was prepared by enzymatic ligation of two chemically synthesized RNA fragments. The synthetic tRNA could be charged with methionine by A.suum mitochondrial extract, although the charging activity was considerably low compared with that of the native tRNA, probably due to lack of modification. Enzymatic probing of the synthetic tRNA showed a very similar digestion pattern to that of the native tRNA Met, which has already been concluded to take an L-shape-like structure [Watanabe et al. (1994) J. Biol. Chem., 269, 22902-22906]. These results suggest that the synthetic tRNA possesses almost the same conformation as the native one, irrespective of the presence or absence of modified residues. The method of preparing the bizarre tRNA used here will provide a useful tool for elucidating the tertiary structure of such tRNAs, because they can be obtained without too much difficulty in the amounts necessary for physicochemical studies such as NMR spectroscopy.