PfSPATR,a Plasmodium falciparum protein containing an altered thrombospondin type I repeat domain is expressed at several stages of the parasite life cycle and is the target of inhibitory antibodies

The annotated sequence of chromosome 2 of Plasmodium falciparum was examined for genes encoding proteins that may be of interest for vaccine development. We describe here the characterization of a protein with an altered thrombospondin Type I repeat domain (PfSPATR) that is expressed in the sporozoite, asexual, and sexual erythrocytic stages of the parasite life cycle. Immunoelectron microscopy indicated that this protein was expressed on the surface of the sporozoites and around the rhoptries in the asexual erythrocytic stage. An Escherichia coli-produced recombinant form of the protein bound to HepG2 cells in a dose-dependent manner and antibodies raised against this protein blocked the invasion of sporozoites into a transformed hepatoma cell line. Sera from Ghanaian adults and from a volunteer who had been immunized with radiation-attenuated P. falciparum sporozoites specifically recognized the expression of this protein on transfected COS-7 cells. These data support the evaluation of this protein as a vaccine candidate.     

Free radical scavenging and metal chelation by Tinospora cordifolia,a possible role in radioprotection

Aqueous extract of T. cordifolia inhibited Fenton (FeSO4) reaction and radiation mediated 2-deoxyribose degradation in a dose dependent fashion with an IC50 value of 700 microg/ml for both Fenton and radiation mediated 2-DR degradation. Similarly, it showed a moderate but dose dependent inhibition of chemically generated superoxide anion at 500 microg/ml concentration and above with an IC50 value of 2000 microg/ml. Aqueous extract inhibited the formation of Fe2+-bipiridyl complex and formation of comet tail by chelating Fe2+ ions in a dose dependent manner with an IC50 value of 150 microg/ml for Fe2+-bipirydyl formation and maximally 200 microg/ml for comet tail formation, respectively. The extract inhibited ferrous sulphate mediated lipid peroxidation in a dose-dependent manner with an IC50 value of 1300 microg/ml and maximally (70%) at 2000 microg/ml. The results reveal that the direct and indirect antioxidant actions of T. cordifolia probably act in corroboration to manifest the overall radioprotective effects.     

A new class of RNA-binding oligomers: peptoid amide and ester analogues

Replication of human immunodeficiency virus type 1 (HIV-1) requires specific interactions of Tat protein with the trans-activation responsive region (TAR) RNA, a 59-base stem-loop structure located at the 5'-end of all HIV mRNAs. Here we report the design, synthesis and in vitro activities of oligopeptoid amide and ester analogues which bind TAR RNA with high affinities. These results show that we have identified a new class of unnatural oligomers for RNA targeting.     

RNAi in human cells: basic structural and functional features of small interfering RNA

We investigated the mechanism of RNA interference (RNAi) in human cells. Here we demonstrate that the status of the 5' hydroxyl terminus of the antisense strand of a siRNA determines RNAi activity, while a 3' terminus block is tolerated in vivo. 5' hydroxyl termini of antisense strands isolated from human cells were phosphorylated, and 3' end biotin groups were not efficiently removed. We found no requirement for a perfect A-form helix in siRNA for interference effects, but an A-form structure was required for antisense-target RNA duplexes. Strikingly, crosslinking of the siRNA duplex by psoralen did not completely block RNA interference, indicating that complete unwinding of the siRNA helix is not necessary for RNAi activity in vivo. These results suggest that RNA amplification by RNA-dependent RNA polymerase is not essential for RNAi in human cells.     

An Adipose Tissue Atlas: An Image-Guided Identification of Human-like BAT and Beige Depots in Rodents

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Characterization of <Emphasis Type="Italic">Gladiolus</Emphasis> Germplasm Using Morphological,Physiological, and Molecular Markers

Estimation of variability and genetic relationships among breeding materials is one of the important strategies in crop improvement programs. Morphological (plant height, spike length, a number of florets/spike), physiological (chlorophyll content, chlorophyll fluorescence, and rapid light curve parameters) and Directed amplification of minisatellite DNA (DAMD) markers were used to investigate the relationships among 50 Gladiolus cultivars. Cluster analysis based on morphological data, physiological characteristics, molecular markers, and cumulative data discriminated all cultivars into seven, five, seven, and six clusters in the unweighted pair-group method using arithmetic mean (UPGMA) dendrogram, respectively. The results of the principal coordinate analysis (PCoA) also supported UPGMA clustering. Variations among the Gladiolus cultivars at phenotypic level could be due to the changes in physiology, environmental conditions, and genetic variability. DAMD analysis using 10 primers produced 120 polymorphic bands with 80% polymorphism showing polymorphic information content (PIC = 0.28), Marker index (MI = 3.37), Nei’s gene diversity (h = 0.267), and Shannon’s information index (I = 0.407). Plant height showed a positive significant correlation with Spike length and Number of florets/spike (r = 0.729, p < 0.001 and r = 0.448, p = 0.001 respectively). Whereas, Spike length showed positive significant correlation with Number of florets/spike (r = 0.688, p < 0.001) and Chlorophyll content showed positive significant correlation with Electron transport rate (r = 0.863, p < 0.001). Based on significant morphological variations, high physiological performance, high genetic variability, and genetic distances between cultivars, we have been able to identify diverse cultivars of Gladiolus that could be the potential source as breeding material for further genetic improvement in this ornamental crop.     

Evidence for glucose-responsive and -unresponsive pools of phospholipid in pancreatic islets

The effect of glucose on the metabolism of phospholipids in pancreatic islets was studied with three radioactive phospholipid precursors, [32P]orthophosphate, [3H]myoinositol, and [3H]arachidonic acid, to determine the conditions necessary for studying the breakdown of prelabeled phospholipids. Islets were incubated in the presence of a radioactive precursor for 60 or 90 min and in the presence of either 3.3 or 16.7 mM glucose to prelabel phospholipids. To study the breakdown of prelabeled phospholipid, the unincorporated precursor was removed and the islets were reincubated for 15 or 20 min under conditions that either did or did not stimulate insulin release. Prelabeling in the presence of a noninsulinotropic concentration of glucose (3.3 mM) supported the incorporation of precursors into almost all islet phospholipids studied. Prelabeling in an insulinotropic concentration of glucose (16.7 mM) increased the incorporation of precursors into a number of phospholipids even more; and reincubation in 16.7 mM glucose caused a rapid loss of radioactivity from specific phospholipids (phosphatidylinositol and/or phosphatidylcholine, depending on the precursor). This breakdown was observed only when islets had been prelabeled in 16.7 mM glucose. The amount of radioactivity lost from phospholipid corresponded roughly to the additional amount incorporated during the prelabeling in the high concentration of glucose. Radioactivity in phospholipids in islets prelabeled in 3.3 mM glucose or in nonsecretagogue metabolic fuels, such as malate plus pyruvate, did not decrease when the islets were subsequently exposed to 16.7 mM glucose, nor did it decrease in 3.3 mM glucose when these islets had been prelabeled in 16.7 mM glucose. Glyceraldehyde, an insulin secretagogue, but not galactose or L-glucose which are not insulin secretagogues, stimulated phospholipid breakdown in islets that had been prelabeled in 16.7 mM glucose. Depriving islets of extracellular calcium, a condition that inhibits insulin release, inhibited phospholipid breakdown. The results suggest that pancreatic islets contain a glucose-responsive and a glucose-unresponsive phospholipid pool. The glucose-responsive pool becomes labeled and undergoes rapid turnover only under stimulatory conditions and may play a role in the stimulus-secretion coupling of insulin release.