Morphological Changes in the Midgut of Aedes aegypti L. (Diptera: Culicidae) Larvae Following Exposure to an Annona coriacea (Magnoliales: Annonaceae) Extract

Bioinsecticides are important in the control of disease vectors, but data regarding their physiological effects on target insects are incomplete. This study describes morphological changes that occur in the midgut of third instar Aedes aegypti L. (Diptera: Culicidae) following treatment with a methanolic extract of Annona coriacea (Magnoliales: Annonaceae). Dissected midguts were subdivided into anterior and posterior regions and analyzed by light and scanning electron microscopy. Insects exposed to the extract displayed intense, destructive cytoplasmic vacuolization in columnar and regenerative midgut cells. The apical surfaces of columnar cells exhibited cytoplasmic protrusions oriented toward the lumen, suggesting that these cells could be involved in apocrine secretory processes and/or apoptosis. We report that A. coriacea extracts induced morphological alterations in the midgut of A. aegypti midgut larvae, supporting the use of plant extracts for control of the dengue vector.     

Molecular mapping of the Rf 3 fertility restoration gene to facilitate its utilization in breeding confection sunflower

The inheritance of a previously identified dominant Rf gene in the confection sunflower line RHA 280 has been determined and designated as Rf ₃ . This study reports the mapping of the Rf ₃ locus using an F2 population of 227 individuals derived from CMS HA 89-3149 × RHA 280. Bulked segregant analysis with 624 pairs of simple sequence repeat (SSR) primers and sequence tagged site (STS) primers identified two polymorphic SSR markers each of linkage groups (LGs) 7 and 11 from a previous map. Results on 90 F2 individuals with 42 polymorphic markers of LGs 7 and 11 indicated that the Rf ₃ gene was linked with eight markers on LG 7, including five SSR markers (ORS328, ORS331, ORS928, ORS966, and ORS1092) and three expressed sequence tag (EST)-SSR markers (HT619-1, HT619-2, and HT1013). Further analysis of the total F2 population of 227 individuals identified a co-dominant marker, ORS328, linked to Rf ₃ at a genetic distance of 0.7 cM on one side, and a female-dominant marker HT1013 at 12.6 cM proximal to Rf ₃ on the other side; a genetic distance of 47.1 cM for LG 7 was covered. This is the first report of an Rf gene from the confection sunflower. The closely linked marker to Rf ₃ will facilitate marker-assisted selection, and provide a basis for cloning of this gene.     

TPX: Biomedical literature search made easy

TPX is a web-based PubMed search enhancement tool that enables faster article searching using analysis and exploration features. These features include identification of relevant biomedical concepts from search results with linkouts to source databases, concept based article categorization, concept assisted search and filtering, query refinement. A distinguishing feature here is the ability to add user-defined concept names and/or concept types for named entity recognition. The tool allows contextual exploration of knowledge sources by providing concept association maps derived from the MEDLINE repository. It also has a full-text search mode that can be configured on request to access local text repositories, incorporating entity co-occurrence search at sentence/paragraph levels. Local text files can also be analyzed on-the-fly. Availability: http://tpx.atc.tcs.com     

Genetic characterization of Chikungunya virus from New Delhi reveal emergence of a new molecular signature in Indian isolates

ABSTRACT: BACKGROUND: Chikungunya (CHIK) is currently endemic in South and Central India and exist as co-infections with dengue in Northern India. In 2010, New Delhi witnessed an outbreak of CHIK in the months October-December. This was the first incidence of a dominant CHIK outbreak in Delhi and prompted us to characterize the Delhi virus strains. We have also investigated the evolution of CHIK spread in India. FINDINGS: Clinical samples were subjected to RT-PCR to detect CHIK viral RNA. The PCR amplified products were sequenced and the resulting sequences were genetically analyzed. Phylogenetic analysis based on partial sequences of the structural proteins E1 and E2 revealed that the viruses in the latest outbreak exhibited ECSA lineage. Two novel mutations, E1 K211E and E2 V264A were observed in all Delhi isolates. In addition, CHIKV sequences from eight states in India were analyzed along with Delhi sequences to map the genetic diversity of CHIKV within the country. Estimates of average evolutionary divergence within states showed varying divergence among the sequences both within the states and between the states. We identified distinct molecular signatures of the different genotypes of CHIKV revealing emergence of a new signature in the New Delhi clade. Statistical analyses and construction of evolutionary path of the virus within the country revealed gradual spread of one specific strain all over the country. CONCLUSION: This study has identified unique mutations in the E1 and E2 genes and has revealed the presence of ancestral CHIKV population with maximum diversity circulating in Maharashtra. The study has further revealed the trend of CHIK spread in India since its first report in 1963 and its subsequent reappearance in 2005.     

Pregnane glycosides from Caralluma adscendens var. fimbriata

Eleven novel pregnane glycosides, 2-7 and 9-13, of which four, i.e., 10-13, comprised a new pregnane-type genin exhibiting a hydroxymethylene instead of a Me group at C(19), and the known pregnane glycoside stalagmoside V (8) were isolated from whole plants of Caralluma adscendens var. fimbriata, a native Indian succulent plant. Their structures were elucidated by extensive 2D-NMR spectroscopic studies.     

Brachy-syndactyly caused by loss of Sfrp2 function

Wnt signaling pathways are regulated both at the intracellular and extracellular levels. During embryogenesis, the in vivo effects of the secreted frizzled-related protein (Sfrp) family of Wnt inhibitors are poorly understood. Here, we show that inactivation of Sfrp2 results in subtle limb defects in mice with mesomelic shortening and consistent shortening of all autopodal elements that is clinically manifested as brachydactyly. In addition, there is soft-tissue syndactyly of the hindlimb. The brachydactyly is caused by decreased chondrocyte proliferation and delayed differentiation in distal limb chondrogenic elements. These data suggest that Sfrp2 can regulate both chondrogenesis and regression of interdigital mesenchyme in distal limb. Sfrp2 can also repress canonical Wnt signaling by Wnt1, Wnt9a, and Wnt4 in vitro. Sfrp2-/- and TOPGAL/Sfrp2-/- mice have a mild increase in beta-catenin and beta-galactosidase staining, respectively, in some phalangeal elements. This however does not exclude a potential concurrent effect on non-canonical Wnt signaling in the growth plate. In combination with what is known about BMP and Wnt signaling in human brachydactylies, our data establish a critical role for Sfrp2 in proper distal limb formation and suggest SFPR2 could be a novel candidate gene for human brachy-syndactyly defects.     

Probing key targets in insulin signaling and adipogenesis using a methanolic extract of <Emphasis Type="Italic">Costus pictus</Emphasis> and its bioactive molecule,methyl tetracosanoate

A methanolic extract of Costus pictus (CPME) showed optimum anti-diabetic activity at 100 ng/ml. Bioactivity-guided purification of CPME led to the isolation of methyl tetracosanoate (MT) which showed an optimum glucose uptake at 1 ng/ml. CPME at 10 μg/ml inhibited adipogenesis whereas fully differentiated adipocytes exhibited a 3-fold increase in lipid accumulation compared to pre-adipocytes. Gene and protein expression of key targets in insulin signaling and adipogenesis pathway revealed that CPME exhibited anti-diabetic activity along with anti-adipogenic activity whereas MT demonstrated only anti-diabetic activity.     

In vitro enzymatic treatment to remove O-linked mannose from intact glycoproteins

The methylotrophic yeast Pichia pastoris is an attractive expression system for heterologous protein production due to its ability to perform posttranslational modifications, such as glycosylation, and secrete large amounts of recombinant protein. However, the structures of N- and O-linked oligosaccharide chains in yeast differ significantly from those of mammalian cells. The most common O-linked glycan structures added by P. pastoris are typically polymers of between one and four α-linked mannose residues, with a subset of glycans being capped by a β-1,2-mannose disaccharide or phosphomannose residue. Such mannosylation of recombinant proteins is considered a key factor in immunomodulation, with mannose-specific receptors binding and promoting enhanced immune responses. As a result of engineering the N-linked glycosylation pathway of P. pastoris, the recombinant proteins expressed in this system are devoid of phospho- and β-mannose on O-linked glycans, leaving only α-mannose polymers. Here we screen a library of α-mannosidases for their ability to decrease the extent of O-mannosylation on glycoproteins secreted from this expression system. In doing so, we demonstrate the utility of the α-1,2/3/6-mannosidase from Jack bean in not only reducing extended O-linked mannose chains but also in specifically hydrolyzing the Man-α-O-Ser/Thr glycosidic bond on intact glycoproteins. As such, this presents for the first time a strategy to remove O-linked glycosylation from intact glycoproteins expressed in P. pastoris. We additionally show that this strategy can be used to significantly decrease the extent of O-mannosylation on commercial products produced in other similar expression systems.