DNA vaccination can break immunological tolerance to PrP in wild-type mice and attenuates prion disease after intracerebral challenge

Transmissible spongiform encephalopathies (TSEs) can be ameliorated by prion protein (PrP)-specific antibodies, but active immunization is complicated by immune tolerance to the normal cellular host protein (PrP(C)). Here, we show that DNA immunization of wild-type mice can break immune tolerance against the prion protein, resulting in the induction of PrP-specific antibody and T-cell responses. PrP immunogenicity was increased by fusion to the lysosomal targeting signal from LIMPII (lysosomal integral membrane protein type II). Although mice immunized with a PrP-LIMPII DNA vaccine showed a dramatic delay in the onset of early disease signs after intracerebral challenge, immunization against PrP also had some deleterious effects. These results clearly confirm the feasibility of using active immunization to protect against TSEs and, in the absence of effective treatments, indicate a suitable alternative for combating the spread of these diseases.     

Expression studies of neogenin and its ligand hemojuvelin in mouse tissues.

Juvenile hemochromatosis is a severe hereditary iron overload disease caused by mutations in the HJV (hemojuvelin) and HAMP (hepcidin) genes. Hepcidin is an important iron regulatory hormone, and hemojuvelin may regulate hepcidin synthesis via the multifunctional membrane receptor neogenin. We explored the expression of murine hemojuvelin and neogenin mRNAs and protein. Real-time RT-PCR analysis of 18 tissues from male and female mice was performed to examine the mRNA expression profiles. To further study protein expression and localization we used immunohistochemistry on several tissues from three mouse strains. Mouse Neo1 mRNA was detectable in the 18 tissues tested, the highest signals being evident in the ovary, uterus, and testis. Neogenin protein was observed in the brain, skeletal muscle, heart, liver, stomach, duodenum, ileum, colon, renal cortex, lung, testis, ovary, oviduct, and uterus. The spleen, thymus, and pancreas were negative for neogenin. The highest signals for Hjv mRNA were detectable in the skeletal muscle, heart, esophagus, and liver. The results indicate that Neo1 mRNA is widely expressed in both male and female mouse tissues with the highest signals detected in the reproductive system. Moreover, Hjv and Neo1 mRNAs are simultaneously expressed in skeletal muscle, heart, esophagus, and liver.     

In vitro assembly into virus-like particles is an intrinsic quality of Pichia pastoris derived HCV core protein

Different variants of hepatitis C virus core protein (HCcAg) have proved to self-assemble in vitro into virus-like particles (VLPs). However, difficulties in obtaining purified mature HCcAg have limited these studies. In this study, a high degree of monomeric HCcAg purification was accomplished using chromatographic procedures under denaturing conditions. Size exclusion chromatography and sucrose density gradient centrifugation of renatured HCcAg (in the absence of structured RNA) under reducing conditions suggested that it assembled into empty capsids. The electron microscopy analysis of renatured HCcAg showed the presence of spherical VLPs with irregular shapes and an average diameter of 35nm. Data indicated that HCcAg monomers assembled in vitro into VLPs in the absence of structured RNA, suggesting that recombinant HCcAg used in this work contains all the information necessary for the assembly process. However, they also suggest that some cellular factors might be required for the proper in vitro assembly of capsids.     

Rab3A and calmodulin regulate acrosomal exocytosis by mechanisms that do not require a direct interaction

The interaction between Rab3A and calmodulin is necessary for the inhibitory effect of Rab3A in neuroendocrine cells. Contrastingly, Rab3A triggers the exocytosis known as acrosome reaction in permeabilized spermatozoa. Here we show that a Rab3A mutant that cannot bind calmodulin was fully capable of triggering acrosomal exocytosis. Additionally, calmodulin by itself abrogated the exocytosis triggered by Rab3A. The effect was observed with both the wild type protein and the calmodulin binding deficient mutant. Our results indicate that the inhibitory and stimulatory effects of Rab3A in different exocytic processes are mediated by different effectors.     

Chlorogenic acid modifies plasma and liver concentrations of: cholesterol,triacylglycerol, and minerals in (fa/fa) Zucker rats

Chlorogenic acid, a phenolic compound found ubiquitously in plants, is an in vitro antioxidant and metal chelator. Some derivatives of chlorogenic acid are hypoglycemic agents and may affect lipid metabolism. Concentrations of cholesterol and triacylglycerols are of interest due to their association with diseases such as non-insulin-dependent-diabetes- mellitus and obese insulin resistance. As little is known about the effects of chlorogenic acid in vivo, studies using obese, hyperlipidemic, and insulin resistant (fa/fa) Zucker rats were conducted to test the effect of chlorogenic acid on fasting plasma glucose, plasma and liver triacylglycerols and cholesterol concentrations. Aditionally, the effects of chlorogenic acid on selected mineral concentrations in plasma, spleen, and liver were determined. Rats were implanted with jugular vein catheters. Chlorogenic acid was infused (5 mg/Kg body weight/day) for 3 weeks via intravenous infusion. Chlorogenic acid did not promote sustained hypoglycemia and significantly lowered the postprandial peak response to a glucose challenge when compared to the same group of rats before Chlorogenic acid treatment. In Chlorogenic acid-treated rats, fasting plasma cholesterol and triacylglycerols concentrations significantly decreased by 44% and 58% respectively, as did in liver triacylglycerols concentrations (24%). We did not find differences (p > 0.05) in adipose triacylglycerols concentration. Significant differences (p < 0.05) in the plasma, liver, and spleen concentration of selected minerals were found in chlorogenic acid-treated rats. In vivo, chlorogenic acid was found to improve glucose tolerance, decreased some plasma and liver lipids, and improve mineral pool distribution under the conditions of this study.     

Identification of Proteins Secreted by Malaria Parasite into Erythrocyte using SVM and PSSM profiles

Background  

Malaria parasite secretes various proteins in infected RBC for its growth and survival. Thus identification of these secretory proteins is important for developing vaccine/drug against malaria. The existing motif-based methods have got limited success due to lack of universal motif in all secretory proteins of malaria parasite.     

Mapping quantitative trait loci for root development under hypoxia conditions in soybean (<Emphasis Type="Italic">Glycine max</Emphasis> L. Merr.)

Key message

Greatest potential, QTLs for hypoxia and waterlogging tolerance in soybean roots were detected using a new phenotypic evaluation method.

Abstract

Waterlogging is a major environmental stress limiting soybean yield in wet parts of the world. Root development is an important indicator of hypoxia tolerance in soybean. However, little is known about the genetic control of root development under hypoxia. This study was conducted to identify quantitative trait loci (QTLs) responsible for root development under hypoxia. Recombinant inbred lines (RILs) developed from a cross between a hypoxia-sensitive cultivar, Tachinagaha, and a tolerant landrace, Iyodaizu, were used. Seedlings were subjected to hypoxia, and root development was evaluated with the value change in root traits between after and before treatments. We found 230 polymorphic markers spanning 2519.2 cM distributed on all 20 chromosomes (Chrs.). Using these, we found 11 QTLs for root length (RL), root length development (RLD), root surface area (RSA), root surface area development (RSAD), root diameter (RD), and change in average root diameter (CARD) on Chrs. 11, 12, 13 and 14, and 7 QTLs for hypoxia tolerance of these root traits. These included QTLs for RLD and RSAD between markers Satt052 and Satt302 on Chr. 12, which are important markers of hypoxia tolerance in soybean; those QTLs were stable between 2 years. To validate the QTLs, we developed a near-isogenic line with the QTL region derived from Iyodaizu. The line performed well under both hypoxia and waterlogging, suggesting that the region contains one or more genes with large effects on root development. These findings may be useful for fine mapping and positional cloning of gene responsible for root development under hypoxia.