Liver microsomal lipids of mice irradiated and administered an extract of turtle spleen

The influence of a tortoise spleen extract (TSE) on lipids of liver endoplasmic reticulum of irradiated (8 Gy) mice has been studied. The administration of TSE immediately after irradiation changes the content of lipid fractions in microsomal membranes preventing the accretion of cholesterol, nonesterified fatty acids, and triacylglycerol. The preparation under study exerts an antioxidant effect.     

Hydrolytic and transglucosylation activities of a purified calf spleen beta-glucosidase.

Certain properties of the transglucosylitic activity and the hydrolytic activity of a purified calf spleen beta-glucosidase (beta-D-glucoside glucohydrolase EC 3.2.1.21) were investigated. There was a stimulation of both activities by sodium taurocholate and "Gaucher's factor". The K-m values for 4-methylumbelliferyl-beta-D-glucoside and glucosylceramide as donors in the transglucosylation reaction were 2 mM and 0.075 mM, respectively. The K-m for ceramide as acceptor was 0.149 mM with both of these compounds. The ability of several glucoside to act as donors was examined. The capacity to catalyze this "transglucosylation" reaction is greatly diminished in spleen tissue samples from Gaucher's patients. The enzyme possesses the capacity to hyrolyze 4-methylumbellifery-beta-D-glucoside, p-nitrophenyl-beta-D-glucoside, glucosylsphingosine, glucosylceramide and deoxycorticosterol-beta-D-glucoside. It is postulated that a single enzyme protein may be responsible for both the hydrolytic and the transglucosylitic activities.     

Synthesis of glucosylceramide by purified calf spleen beta-glucosidase

Radioactive glucocerebroside was formed when purified calf spleen β-glucosidase was incubated in the presence of 4-methylumbelliferyl-β-$\text{D}$-glucoside and (¹⁴C) labeled ceramide. The product was identified by cochromatography on thin layer plates and carrier dilution and crystallization to constant specific activity. The radioactive glucocerebroside was also a substrate for hydrolysis by this same β-glucosidase preparation employed for its synthesis resulting in the liberation of labeled ceramide. Neither methyl-β-$\text{D}$-glucoside nor free D-glucose were effective in producing radioactive glucocerebroside when incubated with labeled ceramide in this system.     

Properties of purified colchicine-binding protein from a cultured carrot cell extract

Colchicine-binding protein (CBP) was purified from a cultured carrot cell extract by DEAE-Sephacel, phosphocellulose and Sephadex G200 column chromatographies. The purified CBP separated into three bands on SDS-polyacrylamide gel electrophoresis. One of them reacted with a monoclonal antibody against chick brain alpha-tubulin and the other two with that against beta-tubulin. Colchicine-binding activity of the purified protein was enhanced by tartrate and inhibited little by an excess of podophyllotoxin. It decayed following first order kinetics, but was more stable than the CBP in the crude extract. The binding constant of the purified CBP for colchicine was 0.57 microM-1 and the number of binding sites of colchicine per mg protein was about 2 nmol. This binding constant is about ten times lower than that of porcine brain tubulin under identical conditions.     

Cell-free translation reconstituted with purified components

We have developed a protein-synthesizing system reconstituted from recombinant tagged protein factors purified to homogeneity. The system was able to produce protein at a rate of about 160 microg/ml/h in a batch mode without the need for any supplementary apparatus. The protein products were easily purified within 1 h using affinity chromatography to remove the tagged protein factors. Moreover, omission of a release factor allowed efficient incorporation of an unnatural amino acid using suppressor transfer RNA (tRNA).     

Pomegranate (Punica granatum) purified polyphenol extract inhibits influenza virus and has a synergistic effect with oseltamivir

Influenza epidemics cause numerous deaths and millions of hospitalizations each year. Because of the alarming emergence of resistance to anti-influenza drugs, there is a need to identify new naturally occurring antiviral molecules. We tested the hypothesis that pomegranate polyphenol extract (PPE) has anti-influenza properties. Using real time PCR, plaque assay, and TCID 50% hemagglutination assay, we have shown that PPE suppresses replication of influenza A virus in MDCK cells. PPE inhibits agglutination of chicken red blood cells (cRBC) by influenza virus and is virucidal. The single-cycle growth conditions indicated that independent of the virucidal effect PPE also inhibits viral RNA replication. PPE did not alter virus ribonucleoprotein (RNP) entry into nucleus or translocation of virus RNP from nucleus to cytoplasm in MDCK cells. We evaluated four major Polyphenols in PPE (ellagic acid, caffeic acid, luteolin, and punicalagin) and demonstrated that punicalagin is the effective, anti-influenza component of PPE. Punicalagin blocked replication of the virus RNA, inhibited agglutination of chicken RBC's by the virus and had virucidal effects. Furthermore, the combination of PPE and oseltamivir synergistically increased the anti-influenza effect of oseltamivir. In conclusion, PPE inhibited the replication of human influenza A/Hong Kong (H3N2) in vitro. Pomegranate extracts should be further studied for therapeutic and prophylactic potential especially for influenza epidemics and pandemics.     

White pulp compartments in the spleen of the turtle Mauremys caspica

Summary The aim of the present study was to analyze the nature of lymphoid and non-lymphoid cellular components occurring in distinct histological compartments of the splenic white pulp of the turtle, Mauremys caspica, in order to define their possible correlations with those of the spleen of higher vertebrates, principally mammals. The white pulp of M.caspica consisted of 3 clearly distinguishable regions: (1) the periateriolar lymphoid sheath, and (2) the inner and (3) the outer zones of the periellipsoidal lymphoid sheath. Reticular cells intimately associated with reticular fibres constituted an extensive meshwork in the periarteriolar lymphoid sheath which housed principally Ig-negative lyphoid cells, mature and immature plasma cells, and interdigitating cells. A few Ig-positive cells were also present in the peripheral region of the periarteriolar lymphoid sheath. The inner and outer zones of the periellipsoidal lymphoid sheath were separated by a discontinuous layer of reticular cell processes. In the inner zone, surface Ig-positive lymphoid cells predominated as well as dendritic cells, resembling ultrastructurally the mammalian follicular dendritic cells, although no germinal centres were found in the turtle spleen. Macrophages, some cytoplasmic Ig-positive cells, and Ig-negative lymphoid cells appeared in the outer zone of the periellipsoidal lymphoid sheath. These results allow us to speculate on a phylogenetic relationship between the periarteriolar lymphoid sheath and the inner and the outer zones of the periellipsoidal lymphoid sheath of the spleen of M. caspica and the periarteriolar lymphoid tissue, the lymphoid follicles and the marginal zone, respectively, of the mammalian splenic white pulp.     

Cloning of Drosophila cells: effect of vitamins and yeast extract components.

Yeast extract, a component of Drosophila cell culture media, is shown to contain substances of high, intermediate, and low molecular weight, that are, respectively, essential, inhibitory, and stimulatory for colony formation in semisolid agar medium. Furthermore, it is shown that high concentrations of pyridoxal greatly increase the cloning efficiency of Drosophilia cells. A cloning method with line Kc is described which routinely gives cloning efficiencies in excess of 20%.     

New polypeptide components purified from mamba venom

New polypeptide components have been isolated from Dendroaspis angusticeps venom using chromatography. Two polypeptides containing 59 and 57 amino acids, called 'DaE1' and 'DaE2' respectively, have been purified to homogeneity and fully sequenced. Spectrometric analysis yielded masses of 6631.5 and 6389.0 Da, respectively. The polypeptides share 98 and 95% identity, respectively, with trypsin inhibitor E (DpE) of Dendroaspis polylepis polylepis. 'DaE' polypeptides inhibit Kv1.1 channels with an IC(50) value in the range of 300 nM. They can be considered as new dendrotoxins, albeit with fairly low affinity as compared to alpha-DTX. 'DaE' polypeptides do not affect Kir2.1 channels.     

Antibacterial activity of murine spleen cell extract.

Exposure to a peptide extract from murine spleen reduced the viable count of E. coli and E. coli spheroplasts. The reduction in viable count was reflected by reduced incorporation of radiolabelled thymidine and was apparently due to a loss of the ability of treated ogranisms to divide.