Altered expression of glycosaminoglycans in metastatic 13762NF rat mamma adenocarcinoma cells

A difference in the expression and metabolism of sulfated glycosaminoglycans between rat mammary tumor cells derived from a primary tumor and those from its metastatic lesions has been observed. Cells from the primary tumor possessed about equal quantities of chondroitin sulfate and heparan sulfate on their cell surfaces but released fourfold more chondroitin sulfate than heparan sulfate into their medium. In contrast, cells from distal metastatic lesions expressed approximately 5 times more heparan sulfate than chondroitin sulfate in both medium and cell surface fractions. This was observed to be the result of differential synthesis of the glycosaminoglycans and not of major structural alterations of the individual glycosaminoglycans. The degree of sulfation and size of heparan sulfate were similar for all cells examined. However, chondroitin sulfate, observed to be only chondroitin 4-sulfate, from the metastases-derived cells had a smaller average molecular weight on gel filtration chromatography and showed a decreased quantity of sulfated disaccharides upon degradation with chondroitin ABC lyase compared to the primary tumor derived cells. Major qualitative or quantitative alterations were not observed for hyaluronic acid among the various 13762NF cells. The metabolism of newly synthesized sulfated glycosaminoglycans was also different between cells from primary tumor and metastases. Cells from the primary tumor continued to accumulate glycosaminoglycans in their medium over a 72-h period, while the accumulation of sulfated glycosaminoglycans in the medium of metastases-derived cells showed a plateau after 18-24 h. A pulse-chase kinetics study demonstrated that both heparan sulfate and chondroitin sulfate were degraded by the metastases-derived cells, whereas the primary tumor derived cells degraded only heparan sulfate and degraded it at a slower rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pitcher plant facilitates prey capture in a sympatric congener

Carnivorous plants avoid below-ground competition for nitrogen by utilizing an alternative nitrogen resource—invertebrate prey, but it remains unclear if sympatric carnivorous plants compete for prey resources. The aim of this study was to investigate if exploitative prey-resource competition occurs between the two sympatric pitcher plant species, Nepenthes rafflesiana and N. gracilis in Singapore. We first investigated if prey-resource partitioning occurs between these two species, and then investigated niche shift in N. gracilis by examining its pitcher contents along an in situ gradient of N. rafflesiana interspecific competition. Our results showed clear evidence of resource partitioning between the two species, but contrary to the expectation of competition, proximity to N. rafflesiana pitchers correlated with higher total prey numbers in N. gracilis pitchers. Our multivariate model of prey assemblages further suggested that N. rafflesiana facilitates N. gracilis prey capture, especially in several ant taxa that are trapped by both species. Concurrently, we found strong evidence for intraspecific competition between N. gracilis pitchers, suggesting that prey resources are exhaustible by pitcher-predation. Our results show that resource partitioning can be associated with facilitative interactions, instead of competition as is usually assumed. Facilitation is more typically expected between phylogenetically distant species, but divergences in resource acquisition strategies can permit facilitation between congeners.     

Influence of aeration during propagation of pitching yeast on fermentation and beer flavor

The effect of yeast propagated at different aeration conditions on yeast physiology, fermentation ability, and beer quality was investigated using three strains of Saccharomyces cerevisiae. It was shown that yeast cells grown under continuous aeration conditions during propagation were almost two times higher as compared with discontinuous aeration conditions. The maximum of cell growth of all samples reached between 36 h and 48 h. The concentration of trehalose was increased under continuous aerated yeasts, whereas glycogen was decreased. It was also observed that the concentration of glycogen and trehalose in yeast cells had no direct effect on subsequent fermentation ability. The effect of yeast propagated under different aeration conditions on subsequent fermentation ability was different from yeast strains, in which the influence will be most pronounced at the first fermentation. Later, the yeasts might regain its original characteristics in the following fermentations. Generally, continuously propagated yeast had a positive effect on beer quality in subsequent fermentation. Hence, the concentration of aroma compounds obtained with yeast propagated under 6 1/h for 48 h aeration was lower than those grown under other aeration conditions in the bottom yeasts; in particular, the amounts of phenylethyl alcohol, ester, and fatty acids were decreased.     

Cloning,purification and biochemical characterisation of an organic solvent-, detergent-, and thermo-stable amylopullulanase from Thermococcus kodakarensis KOD1

Thermostable amylopullulanases can catalyse the hydrolysis of both α-1,4 and α-1,6 glucosidic bonds and are of considerable interest in the starch saccharification industry. In this study, the gene Apu-Tk encoding an extracellular amylopullulanase was cloned from an extremely thermophilic anaerobic archaeon Thermococcus kodakarensis KOD1. Apu-Tk encodes an 1100-amino acid protein with a 27-residue signal peptide, which has a predicted mass of 125 kDa after signal peptide cleavage. Sequence alignments showed that Apu-Tk contains the five regions conserved in all GH57 family proteins. Full-length Apu-Tk was expressed in Escherichia coli and purified to homogeneity. The purified enzyme displayed both pullulanase and amylase activity. The optimal temperature for Apu-Tk to hydrolyse pullulan and soluble starch was >100 °C. Apu-Tk was also active at a broad range of pH (4–7), with an optimum pH of ~5.0–5.5. Apu-Tk also retained >30% of its original activity and partially folded globular structure in the presence of 8% SDS or 10% β-mercaptoethanol. The high yield, broad pH range, and stability of Apu-Tk implicate it as a potential enzyme for industrial applications.     

Genetic Polymorphism of Interferon-γ, Interferon-γ Receptor, and Interferon Regulatory Factor-1 Genes in Patients with Hepatitis B Virus Infection

The natural history of hepatitis B virus (HBV) infection is probably related to host immune factors. Interferon-γ (IFN-γ) plays significant roles in immune defense. This study was undertaken to investigate the association between HBV infection and single nucleotide polymorphisms (SNPs) of IFN-γ, IFN-γ receptor (IFNGR)-1 and 2, and interferon regulatory factor (IRF)-1 genes. Between March 2002 and December 2002, 614 Korean patients were enrolled in two different groups: an HBV clearance group (n = 201), who were hepatitis B surface antigen (HBsAg) negative with antibodies to HBsAg and hepatitis B core antigen, and an HBV persistence group (n = 413), who were repeatedly HBsAg positive. We assessed polymorphisms in the IFN-γ gene at position +874, in the IFNGR-1 gene at positions −56 and +95, in the IFNGR-2 gene at the second position of codon 64 (Gln64Arg), and in the IRF-1 gene promoter (−410, −388), and the genotype distributions of the HBV clearance and persistence groups were compared. On the basis of unconditional logistic regression analysis with adjustment for age and sex, no statistically significant association with susceptibility to persistent HBV infection was observed with the IFN-γ, IFNGR-1 and 2, and IRF-1 gene polymorphisms under the codominant, dominant, and recessive models.     

Affinity enhancement of bispecific antibody against two different epitopes in the same antigen.

For the enhancement of antibody binding affinity, a bispecific antibody against two different epitopes in human chorionic gonadotropin hormone, one is in alpha-subunit and the other is in beta-subunit, was prepared by chemical recombination using 5,5'-dithiobis(2-nitrobenzoic acid). The epitopes recognized by antibodies were investigated by competitive radioimmunoassay, two-site sandwich radioimmunoassay and additivity assay and a proper epitope pair was chosen for preparation of the bispecific antibody. This bispecific antibody has dual specificity and as much as 17.2-fold higher affinity than that of monoclonal antibody with higher affinity by dual antigen binding radioimmunoassay and Scatchard plot analysis.     

Effects of Ethanol Exposure During Early Pregnancy in Hyperactive, Inattentive and Impulsive Behaviors and MeCP2 Expression in Rodent Offspring

Prenatal exposure to alcohol has consistently been associated with adverse effects on neurodevelopment, which is collectively called fetal alcohol spectrum disorder (FASD). Increasing evidence suggest that prenatal exposure to alcohol increases the risk of developing attention deficit/hyperactivity disorder-like behavior in human. In this study, we investigated the behavioral effects of prenatal exposure to EtOH in offspring mice and rats focusing on hyperactivity and impulsivity. We also examined changes in dopamine transporter and MeCP2 expression, which may underlie as a key neurobiological and epigenetic determinant in FASD and hyperactive, inattentive and impulsive behaviors. Mouse or rat offspring born from dam exposed to alcohol during pregnancy (EtOH group) showed hyper locomotive activity, attention deficit and impulsivity. EtOH group also showed increased dopamine transporter and norepinephrine transporter level compared to control group in the prefrontal cortex and striatum. Prenatal exposure to EtOH also significantly decreased the expression of MeCP2 in both prefrontal cortex and striatum. These results suggest that prenatal exposure to EtOH induces hyperactive, inattentive and impulsive behaviors in rodent offspring that might be related to global epigenetic changes as well as aberration in catecholamine neurotransmitter transporter system.