Insights into differential modulation of receptor function by hinge region using novel agonistic lutropin receptor and inverse agonistic thyrotropin receptor antibodies

We report two antibodies, scFv 13B1 and MAb PD1.37, against the hinge regions of LHR and TSHR, respectively, which have similar epitopes but different effects on receptor function. While neither of them affected hormone binding, with marginal effects on hormone response, scFv 13B1 stimulated LHR in a dose-dependent manner, whereas MAb PD1.37 acted as an inverse agonist of TSHR. Moreover, PD1.37 could decrease the basal activity of hinge region CAMs, but had varied effects on those present in ECLs, whereas 13B1 was refractory to any CAMs in LHR. Using truncation mutants and peptide phage display, we compared the differential roles of the hinge region cysteine box-2/3 as well as the exoloops in the activation of these two homologus receptors.     

Crystal structure of the FK506 binding domain of Plasmodium falciparum FKBP35 in complex with FK506

The emergence of multi-drug-resistant strains of Plasmodium parasites has prompted the search for alternative therapeutic strategies for combating malaria. One possible strategy is to exploit existing drugs as lead compounds. FK506 is currently used in the clinic for preventing transplant rejection. It binds to a alpha/beta protein module of approximately 120 amino acids known as the FK506 binding domain (FKBD), which is found in various organisms, including human, yeast, and Plasmodium falciparum (PfFKBD). Antiparasitic effects of FK506 and its analogues devoid of immunosuppressive activities have been demonstrated. We report here the crystallographic structure at 2.35 A resolution of PfFKBD complexed with FK506. Compared to the human FKBP12-FK506 complex reported earlier, the structure reveals structural differences in the beta5-beta6 segment that lines the FK506 binding site. The presence in PfFKBD of Cys-106 and Ser-109 (substituting for His-87 and Ile-90, respectively, in human FKBP12), which are 4-5 A from the nearest atom of the FK506 compound, suggests possible routes for the rational design of analogues of FK506 with specific antiparasitic activity. Upon ligand binding, several conformational changes occur in PfFKBD, including aromatic residues that shape the FK506 binding pocket as shown by NMR studies. A microarray analysis suggests that FK506 and cyclosporine A (CsA) might inhibit parasite development by interfering with the same signaling pathways.     

Tetrahydro-4-quinolinamines identified as novel P2Y(1) receptor antagonists

High-throughput screening of the GSK compound collection against the P2Y(1) receptor identified a novel series of tetrahydro-4-quinolinamine antagonists. Optimal substitution around the piperidine group was pivotal for ensuring activity. An exemplar analog from this series was shown to inhibit platelet aggregation.     

Purification and characterization of a phospholipase A2 from the venom of the coral snake, Micrurus fulvius microgalbineus (Brown and Smith).

A phospholipase A2 was purified from the Mexican coral snake Micrurus fulvius microgalbieus (Brown and Smith). Gel filtration of the soluble crude venom on Sephadex g-50 resolved five fractions, of which fraction II had 98% of the total phospholipase activity. This fraction was rechromatographed on a CM-cellulose column that resolved eight fractions, four of which had an important phospholipase activity. The first fraction (II-1) was homogeneous by polyacrylamide-gel electrophoresis and displayed a phospholipase specific activity of 920 units/mg of protein. The apparent molecular weight as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis was approx. 14000. The amino acid analysis revealed the presence of 119 amino acid residues, with 12 half-cystines. the N-terminal sequence was shown to be Ser-Leu-Leu-Asx-Phe-Lys-Asx-Met-Ile-Glu-Ser-Thr..., which is homologous with that of phospholipases from other snake venoms.     

2,5-Dimethyl-4-hydroxy-3(2H)-furanone as an Anti-biofilm Agent Against Non-Candida albicans Candida Species

Mycopathologia - The predominance of non-Candida albicans Candida (NCAC) species causing healthcare-associated infections has increased over the last decade pertaining to their ability to form...     

Promoters of two anther-specific genes confer organ-specific gene expression in a stage-specific manner in transgenic systems

Differential screening of a stage-specific cDNA library of Indica rice has been used to identify two genes expressed in pre-pollination stage panicles, namely OSIPA and OSIPK coding for proteins similar to expansins/pollen allergens and calcium-dependent protein kinases (CDPK), respectively. Northern analysis and in situ hybridizations indicate that OSIPA expresses exclusively in pollen while OSIPK expresses in pollen as well as anther wall. Promoters of these two anther-specific genes show the presence of various cis-acting elements (GTGA and AGAAA) known to confer anther/pollen-specific gene expression. Organ/tissue-specific activity and strength of their regulatory regions have been determined in transgenic systems, i.e., tobacco and Arabidopsis. A unique temporal activity of these two promoters was observed during various developmental stages of anther/pollen. Promoter of OSIPA is active during the late stages of pollen development and remains active till the anthesis, whereas, OSIPK promoter is active to a low level in developing anther till the pollen matures. OSIPK promoter activity diminishes before anthesis. Both promoters show a potential to target expression of the gene of interest in developmental stage-specific manner and can help engineer pollen-specific traits like male-sterility in plants. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Accessions: OSIPA cDNA, AF220610; OSIPK cDNA, AF312920; OSIPA partial gene and upstream promoter region, AY166659; OSIPK gene-specific and upstream sequence, AY168440.