Heterogeneity amongst 5-HT₃ receptor subunits: is this significant?

The serotonin 3 (5-HT?) receptor is a ligand gated ion channel unlike the other 5-HT receptors which are G protein coupled receptors. The functional 5-HT? receptor forms a pentamer of five symmetrically arranged subunits surrounding a central pore. The 5-HT(3A) subunit was first identified at a molecular level and can form functional homomers or heteromers with the 5-HT(3B) subunit. Recently, three new 5-HT? subunits have been discovered and these can also form functional heteromers with the 5-HT(3A) subunit. In addition, splice variants of the 5-HT? subunits have also been reported. These findings have markedly increased the complexity of the 5-HT? receptor and may form part of the explanation of unresolved differences between studies investigating 5-HT? receptor function in cell lines compared with native tissues. In this review we discuss the properties of the different subunits and their distribution to determine if they contribute to functional changes in the 5-HT? receptor. Several recent pharmacogenomic studies have revealed single nucleotide polymorphisms (SNPs) and other variations in the different 5-HT? receptor subunits that are associated with various clinical conditions. We discuss the implications of these findings with respect to drug design and tailored pharmacogenomic therapies.     

cagA gene variants in Malaysian Helicobacter pylori strains isolated from patients of different ethnic groups

Helicobacter pylori infection of a distinct subtype of cagA may lead to different pathological manifestation. The aim of this study is to determine the presence of cagA gene and its variants in H. pylori infection among different ethnic groups and its effect on gastroduodenal diseases. Overall detection of cagA among the 205 clinical isolates of H. pylori was 94%. Variations in size of the 3' region of cagA gene were examined among 192 Malaysian H. pylori cagA-positive strains. Results showed that three cagA variants differing in fragment length of PCR products were detected and designated as type A (621-651bp), type B (732-735bp) and type C (525 bp). Although there was no association between any of the cagA subtypes with peptic ulcer disease (p>0.05), an association between cagA subtypes with a specific ethnic group was observed. Specific-cagA subtype A strains were predominantly isolated from Chinese compared to Malays and Indians (p<0.0005), and cagA subtype B strains were predominantly isolated from Malays and Indians compared to Chinese (p<0.05). The cagA type A strains of H. pylori is commonly found in the Chinese patients who have a higher risk of peptic ulcer disease, thus indicating that it could be used as an important clinical biomarker for a more severe infection.     

Factors affecting in vitro regeneration of Ficus carica L. and genetic fidelity studies using molecular marker

Journal of Plant Biochemistry and Biotechnology - A facile method for regeneration of fig (Ficus carica L.) is in demand given the inability of the varieties having persistent type fruiting habit...