Inactivation of factor Va by plasmin

The inactivation of Factor Va by plasmin was studied in the presence and absence of phospholipid vesicles and calcium ions. The cleavage patterns of bovine Factor Va and its isolated subunits were analyzed using polyacrylamide gel electrophoresis, and the progress of inactivation was monitored by clotting assays and measurements of prothrombin activation using 5-dimethylaminonaphthalene-1-sulfonylarginine-N-(3-ethyl-1,5-penta nediyl)amide. In addition, the ability of prothrombin and Factor Xa to protect Factor Va from inactivation by human plasmin was examined. The data presented indicate that the cofactor Factor Va is inactivated rapidly upon its interaction with human plasmin. The rate of inactivation is significantly enhanced in the presence of phospholipid vesicles, suggesting that the inactivation process is a membrane-bound phenomenon. The isolated D component (heavy chain of factor Va) was found to be slowly degraded by human plasmin, giving rise to cleavage products different from those obtained with activated protein C and Factor Xa. However, the 48- and 30-kDa fragments obtained from human plasmin degradation of component E (light chain of Factor Va) appear to be similar to those obtained following the proteolysis of the same subunit by activated protein C and Factor Xa.     

EXTERNAL MORPHOLOGY AND PIGMENTATION OF THE VAQUITA, PHOCOENA SINUS (CETACEA: MAMMALIA)

The vaquita, Phocoena sinus , is a porpoise in the family Phocoenidae that lives only in the Gulf of California. The external appearance of P. sinus was unknown until 13 fresh specimens were recently examined. The most obvious morphological feature distinguishing P. sinus from its two congeners is the proportionately higher dorsal fin. The most striking features of the pigmentation pattern are the large black eye patches and the black upper and lower lip patches. In both areas, the pigmentation contrasts sharply with the surrounding light gray coloration. The total lengths of the specimens ranged from 70.3 cm (a neonate) to 143.5 cm (an adult female).     

Synthesis of acetone glycerol acyl esters by immobilized lipase ofMucor miehei

Summary The applications of immobilized lipase ofMucor miehei for the synthesis of acetone glycerol acyl ester from acetone glycerol and fatty acid, which is the first step for monoglyceride production was investigated. With a high oleic acid to acetone glycerol ratio (O/A, mol/mol), a high catalytic activity was observed under low water content in the reaction mixture. By the combination of high O/A ratio (>3) and removal of water which was produced during the reaction, the conversion degree was increased to almost 100%. With the O/A ratio of 3, the approximate half-life of the immobilized lipase and productivity of ester was estimated to be 20 days and 869 g product/g immobilized enzyme per 2 half-lives, respectively.     

Release of PYY from pig intestinal mucosa; luminal and neural regulation

The localization, molecular nature and secretion of Peptide YY (PYY), a putative gut hormone belonging to the Pancreatic Polypeptide family of peptides, was studied in pigs. Immunoreactive PYY was identified in a population of endocrine cells in the mucosal epithelium of the pig ileum. Release of PYY was observed in isolated perfused pig ileum in response to luminal stimulation with glucose and vascular administration of the neuropeptide gastrin-releasing peptide (GRP). Electrical stimulation of the vagus nerve supply to the distal small intestine in intact anaesthetized pigs resulted in release of PYY into the circulation. Stimulation of the splanchnic nerves did not affect the basal release of PYY. PYY-immunoreactivity extracted from ileal tissue or released to plasma or perfusate from the ileum was indistinguishable from synthetic porcine PYY by gel filtration and reverse phase HPLC. It is concluded that the secretion of PYY in the pig ileum may be regulated not only by nutritional luminal factors, but also by postsynaptic parasympathetic nerves.     

Y1 and Y2 receptors for neuropeptide Y

By using monoiodinated radioligands of both intact neuropeptide Y (NPY) and of a long C-terminal fragment, NPY13-36, two subtypes of binding sites, which differ in affinity and specificity, have been characterized. The Y1 type of binding site, characterized on a human neuroblastoma cell line, MC-IXC, and a rat pheochromocytoma cell line, PC-12, binds NPY with a dissociation constant (Kd) of a few nanomolar but does not bind NPY13-36. The Y2 type of binding site, characterized on porcine hippocampal membranes and on another human neuroblastoma cell line, SMS-MSN, is of higher affinity and binds both NPY and NPY13-36. None of the binding sites distinguish between NPY and the homologous peptide YY (PYY). It is concluded that NPY/PYY-binding sites occur in two subtypes which may represent two types of physiological receptors.     

Appearance of alpha-smooth muscle actin in human eye lens cells of anterior capsular cataract and in cultured bovine lens-forming cells

Using light and electron-microscopic immunolocalization techniques, and gel electrophoresis combined with immunoblotting, we have examined the expression of cytoskeletal proteins in normal human fetal, child and adult lenses, in human anterior capsular cataract and in bovine lens cells in vivo and in vitro. In this report, we focus our observations on the pattern of actin-isoform expression during normal and pathological situations in vivo and culture conditions. We have noted that cells of developing and mature human lenses as well as bovine lens cells in situ contain only beta- and gamma-actins. In contrast, alpha-smooth muscle (alpha-sm) actin, an isoform typical of smooth muscle differentiation, was demonstrated in bovine lens cells at different times of culture. Moreover, the multilayered cells observed in the subcapsular zone of human anterior capsular cataract were characterized by the presence of alpha-sm actin. Thus, extensive changes in actin-isoform expression take place in lens cells growing in culture and may also occur during cataractogenesis. The biological meaning of the appearance of a marker of myoid differentiation in the ectodermally derived lens-forming cells is discussed.     

Oxidation of n-tetradecane by Candida parapsilosis KSh 21 adsorbed on different glass rings

Summary Living cells of Candida parapsilosis KSh 21 were immobilized by adsorption on different types of glass rings. The presence of n-tetradecane enhanced the cell adsorption especially on normal glass rings. The high adhesion of cellulose-coated glass rings and of sintered glass rings induced a quick adsorption of the cells. The quantity of 1-tetradecanol produced in the cultures of immobilized cells especially on SGR was higher than that of the free cells. Low numbers of free cells released in the immobilized cultures were observed. Better contact between the immobilized cells and oil droplets was noticed.