Physiological and biochemical investigations on egg stickiness in common carp

The properties and behaviour of common carp, Cyprinus carpio, eggs in water and in ovarian fluids were studied at different temperature, pH, and with divalent cation concentrations. The biochemical composition of zona radiata externa (ZRE) was analyzed qualitatively and quantitatively on amino acids, carbohydrates, uronic acid and sialic acids using chemical assays; on proteins using electrophoresis. Comparative biochemical studies were performed on the chub, Leuciscus cephalus, the vimba, Vimba vimba and the bleak, Chalcalburnus chalcoides. Eggs of common carp became sticky within seconds after mixing with water. Egg stickiness was not affected by water pH in a range of 6-9, by water temperatures between 4 and 30 degrees C, by divalent cations in concentrations < or =20 mmol/l, and by sodium chloride concentrations < or =50 mmol/l. Our investigations indicated that specific proteins of the cyprinid ovarian fluid are controlling (inhibiting) the initiation of egg stickiness: egg stickiness did not develop as long as the eggs were incubated in ovarian fluid. When however the ovarian fluid proteins were removed from the ovarian fluid by heat treatment, eggs developed stickiness within seconds, like they do in water. Biochemically, the ZRE consisted of nine types of proteins whereby four of them were glycoproteins. Glucose, fructose, galactose, and uronic acids were the major carbohydrates. Treatment of the egg membrane with invertase or amyloglucosidase did not affect the egg stickiness. Treatment with protease prevented stickiness. From these results and from additional histochemical results, we conclude that glycoproteins are likely to be the molecules responsible for stickiness.     

Multiregional Periodic Matrix for Modeling the Population Dynamics of Sardine (<Emphasis Type="Italic">Sardina pilchardus</Emphasis>) Along the Moroccan Atlantic Coast: Management Elements for Fisheries

In this paper, we present a deterministic time discrete mathematical model based on multiregional periodic matrices to describe the dynamics of Sardina pilchardus in the Central Atlantic area of the Moroccan coast. This model deals with two stages (immature and mature) and three spatial zones where sardines are supposed to migrate from one zone to another. The population dynamics is described by an autonomous recurrence equation N(t + 1) = A.N(t), where A is a positive matrix whose entries are estimated using data collected during biannual acoustic surveys carried out from 2001 to 2003 onboard the Norwegian research vessel “Dr Fridtjof Nansen”. The dominant eigenvalue λ of A that gives the long-term growth rate of fish population is smaller than one. This agrees with the stock decrease observed in the data collected. We show that λ is highly sensitive to the recruitment rate and much less sensitive to the reproduction rate. These results can clearly be used to define an efficient scenario in order to fight for instance against a stock decrease.     

Cucurbitacins from Bryonia cretica

From the roots of Bryonia cretica L. two new cucurbitacins, isocucurbitacins G (1) and H (2), along with three known cucrbitacins, cucurbitacins G (3), H (4), and J (5) were isolated. The structures of 1 and 2 were determined on the basis of 1D and 2D NMR spectroscopic analysis and X-ray crystallography. The relative stereochemistries of the side chains of 3–5 were also established by comparison of their NMR data and X-ray crystallography.     

Silymarin modulates Cisplatin-induced oxidative stress and hepatotoxicity in rats

Cisplatin (CDDP) is a widely used anticancer drug, but at high dose, it can produce undesirable side effects such as hepatotoxicity. Because silymrin has been used to treat liver disorders, the protective effect of silymarin on CDDP-induced hepatotoxicity was evaluated in rats. Hepatotoxicity was determined by changes in serum alanine aminotransferase [ALT] and aspartate aminotransferase [AST], nitric oxide [NO] levels, albumin and calcium levels, and superoxide dismutase [SOD], glutathione peroxidase [GSHPx] activities, glutathione content, malondialdehyde [MDA] and nitric oxide [NO] levels in liver tissue of rats. Male albino rats were divided into four groups, 10 rats in each. In the control group, rats were injected i.p. with 0.2 ml of propylene glycol in saline 75/25 (v/v) for 5 consecutive days [Silymarin was dissolved in 0.2 ml of propylene glycol in saline 75/25 v/v]. The second group were injected with CDDP (7.5 mg /kg, I.P.), whereas animals in the third group were i.p. injected with silymarin at a dose of 100 mg/kg/day for 5 consecutive days. The Fourth group received a daily i.p. injection of silymarin (100 mg/kg/day for 5 days) 1 hr before a single i.p. injection of CDDP (7.5 mg/kg). CDDP hepatotoxicity was manifested biochemically by an increase in serum ALT and AST, elevation of MDA and NO in liver tissues as well as a decrease in GSH and the activities of antioxidant enzymes, including SOD, GSHPx in liver tissues. In addition, marked decrease in serum NO, albumin and calcium levels were observed. Serum ALT, AST, liver NO level, MDA was found to decreased in the combination group in comparison with the CDDP group. The activities of SOD, GSHPx, GSH and serum NO were lower in CDDP group than both the control and CDDP pretreated with silymarin groups. The results obtained suggested that silymarin significantly attenuated the hepatotoxicity as an indirect target of CDDP in an animal model of CDDP-induced nephrotoxicity.     

Oncolytic adenovirus: A tool for cancer therapy in combination with other therapeutic approaches

Cancer therapy using oncolytic viruses is an emerging area, in which viruses are engineered to selectively propagate in tumor tissues without affecting healthy cells. Because of the advantages that adenoviruses (Ads) have over other viruses, they are more considered. To achieve tumor selectivity, two main modifications on Ads genome have been applied: small deletions and insertion of tissue- or tumor-specific promoters. Despite oncolytic adenoviruses ability in tumor cell lysis and immune responses stimulation, to further increase their antitumor effects, genomic modifications have been carried out including insertion of checkpoint inhibitors and antigenic or immunostimulatory molecules into the adenovirus genome and combination with dendritic cells and chemotherapeutic agents. This study reviews oncolytic adenoviruses structures, their antitumor efficacy in combination with other therapeutic strategies, and finally challenges around this treatment approach.     

Evidence that endothelial lipase remodels high density lipoproteins without mediating the dissociation of apolipoprotein A-I

Endothelial lipase (EL) is a triglyceride lipase gene family member that has high phospholipase and low triglyceride lipase activity. The aim of this study was to determine whether the phospholipase activity of EL is sufficient to remodel HDLs into small particles and mediate the dissociation of apolipoprotein A-I (apoA-I). Spherical, reconstituted HDLs (rHDLs) containing apoA-I only [(A-I)rHDLs], apoA-II only [(A-II)rHDLs], or both apoA-I and apoA-II [(A-I/A-II) rHDLs] were prepared. The rHDLs, which contained only cholesteryl esters in their core and POPC on the surface, were incubated with EL. As the rHDLs did not contain triacylglycerol, only the POPC was hydrolyzed. Hydrolysis was greater in the (A-I/A-II)rHDLs than in the (A-I)rHDLs. The (A-II)rHDL phospholipids were not hydrolyzed by EL. EL remodeled the (A-I)rHDLs and (A-I/A-II)rHDLs, but not the (A-II)rHDLs, into smaller particles. The reduction in particle size was related to the amount of phospholipid hydrolysis, with the diameter of the (A-I/A-II)rHDLs decreasing more than that of the (A-I)rHDLs. These changes did not affect the conformation of apoA-I, and neither apoA-I nor apoA-II dissociated from the rHDLs. Comparable results were obtained when human plasma HDLs were incubated with EL. These results establish that the phospholipase activity of EL remodels plasma HDLs and rHDLs into smaller particles without mediating the dissociation of apolipoproteins.