Influence of Flavonoids on Nodulation and Carbon Partitioning in Pea-Rhizobium Symbiosis

Rhizospheric application of nod regulators influenced the nodulation status, nodule efficiency and partitioning of assimilated CO₂ in Pisum sativum-Rhizobium leguminosarum symbiosis. Depending upon the plant growth stage, naringenin and flavone enhanced nodule number (22.8–87.6%), nodule weight (19.2–35.2%) and nitrogenase activity (17.8–108.6%). Syringaldehyde had negative effect on various parameters of symbiosis. Proportion of ¹⁴C-assimilates was higher in nodules of plants from naringenin and flavone treatments as compared to the control or syringaldehyde treatments. The enhanced nodule efficiency in naringenin and flavone treatments was reflected in the increased N content (12.7–50.4%) and biomass (4.3–35.1%) of plants.     

Painting with a molecular brush: genomic/proteomic interfacing to define the drug action profile of novel solid-tumor selective anticancer agents.

XK469 is an investigational anticancer agent that exhibits antiproliferative activity in tumor-bearing animal models. We examined the drug-action profile of this agent at the molecular level regarding alterations induced in gene expression and proteins in HCT-116 human colon adenocarcinoma cells. We used a unique cDNA microarray (GeneMap(TM) Cancerarray) comprising 1152 human tumor-related genes and 2-D gel electrophoresis, respectively, following a 24-hour exposure to a drug concentration that killed a two-log fraction of HCT-116 clonogenic cells. Functional gene cluster profile (FGCP) analysis of the 71 out of 1152 genes that displayed a >2-fold increase or decrease in expression (over untreated control) identified a drug-specific involvement of the MAPK signal transduction pathway. MAPK signaling together with the involvement of ubiquitin proteins from 2-D gel electrophoresis suggest a novel drug-action profile at the molecular level for the in vitro antiproliferative activity of XK469.     

Correction to: Combined therapeutic efficacy of carvacrol and X-radiation against 1,2-dimethyl hydrazine-induced experimental rat colon carcinogenesis

Molecular and Cellular Biochemistry -     

IND-enzymes: a repository for hydrolytic enzymes derived from thermophilic and psychrophilic bacterial species with potential industrial usage

Extremophiles - Biocatalysts provide many advantages over the traditional chemically assisted processes prevalent in industries. Consequently, the search for novel enzymes has increased over the...     

Evidence for Co-evolution of West Nile Virus and House Sparrows in North America

West Nile virus (WNV) has been maintained in North America in enzootic cycles between mosquitoes and birds since it was first described in North America in 1999. House sparrows (HOSPs; Passer domesticus) are a highly competent host for WNV that have contributed to the rapid spread of WNV across the U.S.; however, their competence has been evaluated primarily using an early WNV strain (NY99) that is no longer circulating. Herein, we report that the competence of wild HOSPs for the NY99 strain has decreased significantly over time, suggesting that HOSPs may have developed resistance to this early WNV strain. Moreover, recently isolated WNV strains generate higher peak viremias and mortality in contemporary HOSPs compared to NY99. These data indicate that opposing selective pressures in both the virus and avian host have resulted in a net increase in the level of host competence of North American HOSPs for currently circulating WNV strains.     

Structural evidence for the order of preference of inorganic substrates in mammalian heme peroxidases: crystal structure of the complex of lactoperoxidase with four inorganic substrates,SCN-, I-, Br– and Cl-

Lactoperoxidase (LPO) is a member of the family of mammalian heme peroxidases. It catalyzes the oxidation of halides and pseudohalides in presence of hydrogen peroxide. LPO has been co-crystallized with inorganic substrates, SCN^-, I^-, Br^- and Cl^-. The structure determination of the complex of LPO with above four substrates showed that all of them occupied distinct positions in the substrate binding site on the distal heme side. The bound substrate ions were separated from each other by one or more water molecules. The heme iron is coordinated to His-351 N^ϵ2 on the proximal side while it is coordinated to conserved water molecule W-1 on the distal heme side. W-1 is hydrogen bonded to Br^- ion which is followed by Cl^- ion with a hydrogen bonded water molecule W-5′ between them. Next to Cl^- ion is a hydrogen bonded water molecule W-7′ which in turn is hydrogen bonded to W-8′ and N atom of SCN^-. W-80 is hydrogen bonded to W-9′ which is hydrogen bonded to I^-. SCN^- ion also interacts directly with Asn-230 and through water molecules with Ser-235 and Phe-254. Therefore, according to the locations of four substrate anions, the order of preference for binding to lactoperoxidase is observed as Br^- > Cl^- > SCN^- > I^-. The positions of anions are further defined in terms of subsites where Br^- is located in subsite 1, Cl^- in subsite 2, SCN^- in subsite 3 and I^- in subsite 4.     

Priming biotic factors for optimal protocorm-like body and callus induction in hybrid Cymbidium (Orchidaceae), and assessment of cytogenetic stability in regenerated plantlets

Protocorm-like bodies (PLBs) and callus were induced in epiphytic hybrid Cymbidium Twilight Moon ‘Day Light’, where induction capacity was strongly explant dependent. Following the use of various explant sources (PLB, leaf tip or base, root tip or base, cell and tissue ‘suspension’), highest PLB formation and callus induction occurred when we used whole PLBs, PLB segments or PLB transverse thin cell layers (tTCLs) or longitudinal TCLs (lTCLs). Plantlet growth and photosynthetic state from whole or bisected PLBs, as well as from tTCLs were not significantly different, after analysis of chlorophyll content. However plantlets generated from lTCLs showed lower values for growth and photosynthetic parameters. All resultant plants were shown to be cytogenetically identical using RAPD and mtDNA analysis despite cytological variation and endopolyploidy occuring between different plant parts. Acclimatization and survival rate was shown to be 100% in the generated plants.     

Reproductive characterization and preliminary studies on controlled breeding of Annatto (Bixa orellana L.)

Annatto (Bixa orellana L.) is an important dye-yielding medium-sized tree occurring in the tropics. Investigations aimed at elucidating the reproductive characters as well as establishing a set of breeding parameters for genetic improvement of B. orellana was carried out. Records on pollen/ovule ratios of annatto showed that this species is xenogamous. The acetolyzed pollen of B. orellana was tricolporate. The fluorochromatic test showed 95% pollen viability. The viability of the pollen grains decreased sharply after 4 h from anther dehiscence. The optimum time range for artificial pollination was standardized between 12:00 and 13:00 h. A high in vitro germination rate (92%) of freshly collected pollen was recorded in modified Brewbaker’s medium with 15% sucrose. Resource allocation studies showed that the construction of each flower cost 1.162 g. The floral vegetative cost was 75%. Of the total allocation, 21% was spent by the stamens. Based on identified reproductive characters, controlled pollination experiments were conducted by selecting four morphologically distinct parent plants: (1) green-fruited with reddish spines, (2) red-fruited, (3) brown large-fruited, and (4) with brown distorted fruits. In artificial cross-pollination experiments, wide variation ranges in fruit set (0–95%) and fruit maturation (0–85%) were observed in different crosses. The number of seeds per capsule also showed variation (0–40 per capsule). Germination studies of seeds raised from different crosses showed a maximum 93% germination. The present study proved that improvement in B. orellana could be achieved by adopting breeding techniques using specifically selected parents.