Glucosyltransferase from Streptococcus sobrinus Catalyzes Glucosylation of Catechin

We previously showed that the polymeric forms of polyphenols present in oolong tea extract exhibited strong inhibitory activities against glucosyltransferases (GTases) of mutans streptococci, while green tea extract, which is rich in catechins, did not show such GTase-inhibitory activities. In this study, (+)-catechin [2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-1-benzopyran-3,5,7-triol] was found to be glucosylated by the GTase of Streptococcus sobrinus 6715 with sucrose as the substrate, and the product was identified as 4(prm1)-O-(alpha)-d-glucopyranosyl-(+)-catechin, with a molecular weight of 452. The (alpha)-glucosylated (+)-catechin did not exhibit significant inhibition of glucan synthesis from sucrose by the GTase, which is in contrast to the polymeric polyphenols isolated from oolong tea leaves.     

Ingestion of particulate matter by the outer surface cells of the mollusc mantle

A study of the ingestion of particulate matter from the pallial space located between the shell and the outer surface of the mantle of Isognomon alatus and Pinctada radiata was undertaken with the aid of the electron microscope. For this purpose colloidal thorium dioxide (thorotrast) was introduced into the pallial space for periods of 1–5 days after which time the mantle was excised and prepared for examination with the electron microscope. After 24 hours thorotrast micelles were observed in the pallial space, on the surface of the microvilli, in small pinocytotic vesicles between the bases of the microvilli, in vacuoles undergoing coalescence and finally in large dense bodies (lysosomes). Amoebocytes in the pallial space also participate in the removal of particulate matter in a manner similar to that described for the surface epithelium. During active ingestion the Golgi apparatus changes from a vesicular to a lamellar form. The method of ingestion observed in the surface epithelia and the amoebocytes is similar to the ingestion of protein and other particulate material reported for a variety of vertebrate tissues.     

Lateral flagellar antigen of Vibrio alginolyticus and Vibrio harveyi: existence of serovars common to the two species

The antigenicity of lateral (L-) flagella of two marine vibrios, Vibrio alginolyticus and V. harveyi, was studied, and the two species were found to have common antigenicity of their flagella. Antisera against L-flagella were prepared by immunizing rabbits with highly purified L-flagellar filaments. H-Agglutination tests with the anti-L-flagella antisera showed that four H-serovars existed in these species and that two of them were shared by the two species. Cross reactivity between H-serovars of these two species and other vibrios having lateral flagella, such as V. parahaemolyticus, V. campbellii, V. proteus, or V. fluvialis, was not observed in the H-agglutination test, although partial common antigenicity was observed in the gel diffusion test with flagellin monomers. These observations suggest that surface antigenic determinants of the lateral flagella of V. alginolyticus and V. harveyi are specific to these two species but internal antigenic determinants buried in the flagellar filaments are partially shared with other vibrio species.     

The phosphorylation site for casein kinase II on 20,000-Da light chain of gizzard myosin

The 20-kDa light chain isolated from gizzard myosin has recently been reported to be phosphorylated by casein kinase II at a site distinct from that phosphorylated by Ca²⁺- and calmodulin-dependent myosin light-chain kinase. In the present study, the site phosphorylated by casein kinase II has been analyzed through procedures including tryptic digestion of the radioactively phosphorylated light chain and CNBr cleavage of the purified tryptic phosphopeptide, followed by amino acid analysis of these phosphopeptides. Comparison of the amino acid compositions of these peptides with the previously reported sequence has indicated that the phosphorylation site is threonine-134 of the light chain. The significance of the phosphorylation of the light chain by casein kinase II, as well as the substrate specificity of the protein kinase, is discussed on the basis of the result.