BDNF and DARPP-32 genes are not risk factors for schizophrenia in the Malay population

A number of studies have pointed to the association of BDNF (brain-derived neurotrophic factor) and DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, 32 kDa) with schizophrenia. The purpose of this study was to determine whether these two genes are involved in the pathogenesis of schizophrenia in the Malay population. Two single nucleotide polymorphisms Val66Met of BDNF, -2036C>G and g.1238delG of DARPP-32 were genotyped in the Malay population in 200 patients with schizophrenia and 256 healthy controls. Analysis of allele and genotype frequencies in these two groups revealed no significant association of BDNF or DARPP-32 polymorphisms with schizophrenia in Malays. This is the first such association study in the Malay population.     

Measurement of the cellular deacetylase activity of SIRT1 on p53 via LanthaScreen® technology

Upon genomic insult, the tumor suppressor p53 is phosphorylated and acetylated at specific serine and lysine residues, increasing its stability and transactivation function. Deacetylases, including the type III histone deacetylase SIRT1, remove acetyl groups from p53 and counterbalance acetyltransferase activity during a DNA damage response. This report describes a series of high-throughput LanthaScreen? time-resolved F?rster resonance energy transfer (TR-FRET) immunoassays for detection of intracellular p53 phosphorylation of Ser15 and acetylation of Lys382 upon treatment with DNA damage agents, such as etoposide. These assays were used to measure the deacetylase activity of SIRT1 and/or Type I/II Histone deacetylases (HDACs). First, BacMam-mediated overexpression of SIRT1 resulted in dose-dependent deacetylation of GFP-p53 following etoposide treatment of U-2 OS cells, confirming that GFP-p53 serves as a SIRT1 substrate in this assay format. Further, overexpression of the acetyltransferase p300 via BacMam increased the acetylation of GFP-p53 at Lys382. Next, siRNA-mediated knockdown of SIRT1 resulted in increased GFP-p53 acetylation, indicating that endogenous SIRT1 activity can also be measured in U-2 OS cells. Consistent with these results, GFP-p53 acetylation was also increased upon treatment of cells with a small-molecule inhibitor of SIRT1, EX-527. The effect of this compound was dramatically increased when used in combination with chemotherapeutic drug and/or the HDAC inhibitor Trichostatin A, confirming a proposed synergistic mechanism of p53 deacetylation by SIRT1 and Type I/II HDACs. Taken together, the cellular assays described here can be used as high-throughput alternatives to traditional immunoassays such as western blotting for identifying pharmacological modulators of specific p53-modifying enzymes.     

Comparative analysis reveals signatures of differentiation amid genomic polymorphism in Lake Malawi cichlids

Background  

Cichlid fish from East Africa are remarkable for phenotypic and behavioral diversity on a backdrop of genomic similarity. In 2006, the Joint Genome Institute completed low coverage survey sequencing of the genomes of five phenotypically and ecologically diverse Lake Malawi species. We report a computational and comparative analysis of these data that provides insight into the mechanisms that make closely related species different from one another.     

Length-weight relationships of eight fish from seagrass meadows in Wenchang,China

The length-weight relationships (LWRs) were studied for eight seagrass fish from Wenchang, China, using gill nets (150*1 m, mesh size 0.5 cm), including Gerres oblongus, Ambassis kopsii, Halichoeres nigrescens, Sillago aeolus, Yongeichthys criniger, Oxyurichthys tentacularis, Lethrinus haematopterus and Hypoatherina tsurugae, in November 2017, March and August 2018. Results suggest that mean LWR parameters b for these eight seagrass fish varied from 2.801 for L. haematopterus to 3.640 for A. kopsii, and r² valued from .950 for L. haematopterus to 0.993 for H. nigrescens. This study will help us to better understand the ecological parameters these seagrass fish.     

17β-estradiol downregulates angiotensin-II-induced endothelin-1 gene expression in rat aortic smooth muscle cells

It is well documented that 17-estradiol (E₂) exerts a cardiovascular protective effect. A possible role of E₂ in the regulation of endothelin-1 (ET-1) production has been reported. However, the complex mechanisms by which E₂ inhibits ET-1 expression are not completely understood. The aims of this study were to examine whether E₂ may alter angiotensin II (Ang II)-induced cell proliferation and ET-1 gene expression and to identify the putative underlying signaling pathways in rat aortic smooth muscle cells. Cultured rat aortic smooth muscle cells were preincubated with E₂, then stimulated with Ang II, and [³H]thymidine incorporation and ET-1 gene expression were examined. The effect of E₂ on Ang-II-induced extracellular signal-regulated kinase (ERK) phosphorylation was tested to elucidate the intracellular mechanism of E₂ in proliferation and ET-1 gene expression. Ang II increased DNA synthesis which was inhibited with E₂ (1–100 nM). E₂, but not 17-estradiol, inhibited the Ang-II-induced ET-1 gene expression as revealed by Northern blotting and promoter activity assay. This effect was prevented by coincubation with the estrogen receptor antagonist ICl 182,780 (1 µM). E₂ also inhibited Ang-II-increased intracellular reactive oxygen species (ROS) as measured by a redox-sensitive fluorescent dye, 2,7-dichlorofluorescin diacetate, and ERK phosphorylation. Furthermore, E₂ and antioxidants, such as N-acetyl cysteine and diphenylene iodonium, decreased Ang-II-induced cell proliferation, ET-1 promoter activity, ET-1 mRNA, ERK phosphorylation, and activator protein-1-mediated reporter activity. In summary, our results suggest that E₂ inhibits Ang-II-induced cell proliferation and ET-1 gene expression, partially by interfering with the ERK pathway via attenuation of ROS generation. Thus, this study provides important new insight regarding the molecular pathways that may contribute to the proposed beneficial effects of estrogen on the cardiovascular system.     

Role of polymer–protein interaction on partitioning pattern of bovine pancreatic trypsinogen and alpha-chymotrypsinogen in polyethyleneglycol/sodium tartrate aqueous two-phase systems

The partitioning pattern of bovine trypsinogen (TRPz) and alpha-chymotrypsinogen (ChTRPz) was investigated in a low impact aqueous two-phase system formed by polyethyleneglycol (PEG) and sodium tartrate (NaTart) pH 5.00. ChTRPz exhibited higher partition coefficients than TRPz did in all the assayed systems. The decrease in PEG molecular weight and the increase in tie line length were observed to displace the partitioning equilibrium of both proteins to the top phase, while phase volume ratios in the range 0.5–1.5 showed not to affect protein partitioning behaviour. Systems formed by PEG of molecular weight 600 with composition corresponding to a high tie line length (PEG 12.93%, w/w and NaTart 21.20%, w/w) are able to recover most of both zymogens in the polymer-enriched phase. A crucial role of PEG–protein interaction in the partitioning mechanism was evidenced by isothermal calorimetric titrations. The major content of highly exposed tryptophan rests, present in ChTRPz molecule, could be considered to be determinant of its higher partition coefficient due to a selective charge transfer interaction with PEG molecule. A satisfactory correlation between partition coefficient and protein surface hydrophobicity was observed in systems formed with PEGs of molecular weight above 4000, this finding being relevant in the design of an extraction process employing aqueous two-phase systems.     

Evolutionary rate variation in Old World monkeys

We analysed over 8 million base pairs of bacterial artificial chromosome-based sequence alignments of four Old World monkeys and the human genome. Our findings are as follows. (i) Genomic divergences among several Old World monkeys mirror those between well-studied hominoids. (ii) The X-chromosome evolves slower than autosomes, in accord with ‘male-driven evolution’. However, the degree of male mutation bias is lower in Old World monkeys than in hominoids. (iii) Evolutionary rates vary significantly between lineages. The baboon branch shows a particularly slow molecular evolution. Thus, lineage-specific evolutionary rate variation is a common theme of primate genome evolution. (iv) In contrast to the overall pattern, mutations originating from DNA methylation exhibit little variation between lineages. Our study illustrates the potential of primates as a model system to investigate genome evolution, in particular to elucidate molecular mechanisms of substitution rate variation.     

Biotransformation kinetics of Pseudomonas putida for cometabolism of phenol and 4-chlorophenol in the presence of sodium glutamate

A kinetic model to describe the degradation of phenol and cometabolictransformation of 4-chlorophenol (4-cp) in the presence of sodium glutamate(SG) has been developed and validated experimentally. The integrated modelaccounts for cell growth, toxicity of 4-cp, cross-inhibitions among the threesubstrates, and the different roles of the specific growth substrate (phenol)and the conventional carbon source (SG) in the cometabolism of 4-cp. In thisternary substrate system, the overall phenol degradation and 4-cp transformation rates are greatly enhanced by the addition of SG since SG is able to attenuate the toxicity of 4-cp and therefore increase the cell growth rate. Model analysis indicates that the maximum specific degradation rate of phenol (0.819 mg (mg.h)^-1) is lowered by SG by up to 46% whereas the specific transformation rate of 4-cp is notdirectly affected by the presence of SG. The competitive inhibition coefficient of 4-cp to phenol degradation (K_i,cp) and that of phenol to 4-cp transformation (K_i,ph) were determined to be 6.49 mg l^-1 and 0.193 mg l^-1, respectively, indicatingthat phenol imposes much larger competitive inhibition to 4-cp transformation than the converse. The model developed can simultaneously predict phenol degradation and 4-cp transformation, and is useful for dealing with cometabolism involving multiple substrates.