Lipoxygenase inhibiting and antioxidant oligostilbene and monoterpene galactoside from Paeonia emodi

Paeoninol and paeonin C, oligostilbene and monoterpene galactoside, have been isolated from the methanolic extract of the fruits of Paeonia emodi. Their structures have been assigned on the basis of spectral analysis including 1D and 2D NMR techniques. In addition, 4-hydroxybenzoic acid 3, gallic acid 4 and methyl gallate 5 have also been reported for the first time from this species. Compounds 1 and 2 have displayed potent inhibitory potential against enzyme lipoxygenase in a concentration-dependent fashion with the IC(50) values 0.77 and 99.5 microM, along with ABTS(.+) radical quenching activity with IC(50) values of 147.5 and 498.2 microM, respectively.     

Cell cycle dysregulation by green tea polyphenol epigallocatechin-3-gallate

Epidemiological, in vitro cell culture, and in vivo animal studies have shown that green tea or its constituent polyphenols, particularly its major polyphenol epigallocatechin-3-gallate (EGCG) may protect against many cancer types. In earlier studies, we showed that green tea polyphenol EGCG causes a G0/G1-phase cell cycle arrest and apoptosis of human epidermoid carcinoma (A431) cells. We also demonstrated that these effects of EGCG may be mediated through the inhibition of nuclear factor kappa B that has been associated with cell cycle regulation and cancer. In this study, employing A431 cells, we provide evidence for the involvement of cyclin kinase inhibitor (cki)-cyclin-cyclin-dependent kinase (cdk) machinery during cell cycle deregulation by EGCG. As shown by immunoblot analysis, EGCG treatment of the cells resulted in significant dose- and time-dependent (i) upregulation of the protein expression of WAF1/p21, KIP1/p27, p16 and p18, (ii) downmodulation of the protein expression of cyclin D1, cdk4 and cdk6, but not of cyclin E and cdk2, (iii) inhibition of the kinase activities associated with cyclin E, cyclin D1, cdk2, cdk4 and cdk6. Taken together, our study suggests that EGCG causes an induction of G1-phase ckis, which inhibit the cyclin-cdk complexes operative in G0/G1 phase of the cell cycle thereby causing a G0/G1-phase arrest of the cell cycle, which is an irreversible process ultimately resulting in an apoptotic cell death. We suggest that the naturally occurring agents such as green tea polyphenols which may inhibit cell cycle progression could be developed as potent anticancer agents for the management of cancer.     

The impact of mass media family planning programmes on current use of contraception in urban Bangladesh

A sample of 871 currently married urban Bangladeshi women was used to assess the impact of mass media family planning programmes on current contraceptive use. The analyses suggested that radio had been playing a significant role in spreading family planning messages among eligible clients; 38% of women with access to a radio had heard of family planning messages while the figures for TV and newspaper were 18.5% and 8.5% respectively. Education, number of living children and current contraceptive use were important predictors of exposure to any mass media family planning messages. There was a negative relationship between breast-feeding and the current use of contraception indicating a low need for contraception among women who were breast-feeding.     

An 18 kDa Acid Phosphatase from Chicken Heart Possesses Phosphotransferase Activity

A low molecular weight acid phosphatase was purified to homogeneity from chicken heart with a specific activity of 42 U/mg and a recovery of about 1%. Nearly 800 fold purification was achieved. The molecular weight was estimated to be 18 kDa by SDS-polyacrylamide gel electrophoresis. Para-nitrophenyl phosphate, phenyl phosphate and flavin mononucleotide were efficiently hydrolysed by the enzyme and found to be good substrates. Fluoride and tartrate had no inhibitory effect while phosphate, vanadate and molybdate strongly inhibited the enzyme. The acid phosphatase was stimulated in the presence of glycerol, ethylene glycol, methanol, ethanol and acetone, which reflected the phosphotransferase activity. When phosphate acceptors such as ethylene glycol concentrations were increased, the ratio of phosphate transfer to hydrolysis was also increased, demonstrating the presence of a transphosphorylation reaction where an acceptor can compete with water in the rate limiting step involving hydrolysis of a covalent phospho enzyme intermediate. Partition experiments carried out with two substrates, para-nitrophenyl phosphate and phenyl phosphate, revealed a constant product ratio of 1.7 for phosphotransfer to ethylene glycol versus hydrolysis, strongly supporting the existence of common covalent phospho enzyme intermediate. A constant ratio of K _cat/K _m, 4.3×10⁴, found at different ethylene glycol concentrations, also supported the idea that the rate limiting step was the hydrolysis of the phospho enzyme intermediate.     

Oxidative toxicity in diabetes and Alzheimer’s disease: mechanisms behind ROS/ RNS generation

Reactive oxidative species (ROS) toxicity remains an undisputed cause and link between Alzheimer’s disease (AD) and Type-2 Diabetes Mellitus (T2DM). Patients with both AD and T2DM have damaged, oxidized DNA, RNA, protein and lipid products that can be used as possible disease progression markers. Although the oxidative stress has been anticipated as a main cause in promoting both AD and T2DM, multiple pathways could be involved in ROS production. The focus of this review is to summarize the mechanisms involved in ROS production and their possible association with AD and T2DM pathogenesis and progression. We have also highlighted the role of current treatments that can be linked with reduced oxidative stress and damage in AD and T2DM.     

Deletion of RB exons 24 and 25 causes low-penetrance retinoblastoma.

A deletion in the tumor-suppressor gene, RB, discovered by quantitative multiplex PCR, shows low penetrance (LP), since only 39% of eyes at risk in this family develop retinoblastoma. The 4-kb deletion spanning exons 24 and 25 (delta24-25) is the largest ever observed in an LP retinoblastoma family. Unlike the usual RB mutations, which cause retinoblastoma in 95% of at-risk eyes and yield no detectable protein, the delta24-25 allele transcribed a message splicing exon 23 to exon 26, resulting in a detectable protein (pRBdelta24-25) that lacks 58 amino acids from the C-terminal domain, proving that this domain is essential for suppression of retinoblastoma. Two functions were partially impaired by delta24-25-nuclear localization and repression of E2F-consistent with the idea that LP mutations generate "weak alleles" by reducing but not eliminating essential activities. However, delta24-25 ablated interaction of pRB with MDM2. Since a homozygous LP allele is considered nontumorigenic, the pRB/MDM2 interaction may be semi- or nonessential for suppressing retinoblastoma. Alternatively, some homozygous LP alleles may not cause tumorigenesis because an additional event is required (the "three-hit hypothesis"), or the resulting imbalance in pRB function may cause apoptosis (the "death allele hypothesis"). pRBdelta24-25 was also completely defective in suppressing growth of Saos-2 osteosarcoma cells. Targeting pRBdelta24-25 to the nucleus did not improve Saos-2 growth suppression, suggesting that C-terminal domain functions other than nuclear localization are essential for blocking proliferation in these cells. Since delta24-25 behaves like a null allele in these cells but like an LP allele in the retina, pRB may use different mechanisms to control growth in different cell types.     

Antibiotic resistance,biofilm production ability and genetic diversity of carbapenem-resistant Pseudomonas aeruginosa strains isolated from nosocomial infections in southwestern Iran

Molecular Biology Reports - This study was aimed to evaluate the antibiotic resistance, biofilm formation, and genetic diversity of carbapenem-resistant Pseudomonas aeruginosa (CRPA) strains...     

Phylogenetic Analysis of Bacterial Isolates from Man-Made High-pH, High-Salt Environments and Identification of Gene-Cassette–Associated Open Reading Frames

Environmental samples were collected from high-pH sites in Pakistan, including a uranium heap set up for carbonate leaching, the lime unit of a tannery, and the Khewra salt mine. Another sample was collected from a hot spring on the shore of the soda lake, Magadi, in Kenya. Microbial cultures were enriched from Pakistani samples. Phylogenetic analysis of isolates was carried out by sequencing 16S rRNA genes. Genomic DNA was amplified by polymerase chain reaction using integron gene-cassette–specific primers. Different gene-cassette–linked genes were recovered from the cultured strains related to Halomonas magadiensis, Virgibacillus halodenitrificans, and Yania flava and from the uncultured environmental DNA sample. The usefulness of this technique as a tool for gene mining is indicated.     

Phylogenetic relationship of Alexandrium tamiyavanichii (Dinophyceae) to other Alexandrium species based on ribosomal RNA gene sequences

The phylogenetic relationship of the thecate PSP-toxin producing dinoflagellate Alexandrium tamiyavanichii Balech to other species of Alexandrium was studied based on nucleotide sequences of the ITS1, ITS2, 5.8S, 18S and 28S subunits of the ribosomal RNA gene. These are the first such sequences available for A. tamiyavanichii, which is one of the producers of paralytic shellfish poisoning toxins in tropical waters. Based on the nucleotide sequences of the 28S, 18S and 5.8S subunits of the rRNA gene, A. tamiyavanichii grouped together with A. tamarense, A. catenella and A. fundyense. More interestingly, A. tamiyavanichii was most closely affiliated to A. tamarense isolates from Thailand. This result reaffirmed conclusions from previous studies that, for the A. tamarense/fundyense/catenella species complex, geographical origin rather than morphology seems to determine genetic relatedness. Results of this study also suggest that A. tamiyavanichii most probably belongs to the same species complex. Ribosomal RNA gene sequences do not separate the PSP toxin producing from the non-producing species of Alexandrium.