Identification, expression, modeled structure and serological characterization of Plasmodium vivax histone 2B

Histones play important role in DNA packaging, replication and gene expression. Here, we describe the isolation and characterization of histone 2B (PvH2B) gene from the most common but non-cultivable human malaria parasite Plasmodium vivax. The isolated cDNA clone of PvH2B was allowed to express in Escherichia coli and the recombinant protein was purified by affinity chromatography. The expressed PvH2B protein showed DNA-binding properties on the South-Western analysis and the confocal microscopy localized it in the parasite nucleus. This gene is actively expressed during blood stages of the parasite and all P. vivax patients produced antibodies against the protein. The mRNA of PvH2B was found to contain a poly(A) tail at its 3' end, unlike abundant mRNA of human H2B. The encoded polypeptide is 118 amino acid long contains a nuclear targeting site, a signature motif of H2B and showed 74% homology to its host molecule. The structure of PvH2B showed that it has certain differences from that of its host at critical functional sites (viz acetylation, methylation, trypsin cleavage, DNA-binding and inter-histone interaction) which are required for general gene expression and DNA packaging. The distinctive structural features of P. vivax H2B described here may help in designing the specific antimalarial drugs

Insights into Insect Resistance in Pulse Crops: Problems and Preventions

Globally, insect pests cause considerable damage to pulse crops. Hence developing broad-spectrum resistance against insect pests has been a major challenge to pulse growers and scientists. Traditionally, cultural practices and synthetic insecticides are being utilized for effective control of insect pests since ages. Apart from these, other strategies such as host plant resistance, insect-resistant transgenic crops, and IPM are also being used to manage the infestation in pulse crops. Though screening of genetic resources for insect resistance has been promising in some pulse crops, fertility barriers and linkage drag minimize the effective utilization of identified resistance in commercially viable crop breeding programs. In parallel, insect-resistant transgenic plants have been developed using various insecticidal proteins from various sources including Bacillus thuringiensis endotoxin, plant protease inhibitors, chitinases, alpha-amylase inhibitors, secondary metabolites, and vegetative insecticidal proteins (VIPs). Deploying transgenic plants with high levels of toxin expression by gene pyramiding is another practical option to delay the resistance development in insects. Nevertheless, the success achieved so far in managing insect pests is limited mainly due to the complex mechanisms underlying the defense strategies together with the lack of precision in screening techniques. Here, we discuss the recent progress and current status of studies toward developing resistance to the most common insect pests of pulses. This chapter points the lack of detailed molecular studies exploring the insect resistance that can advance our knowledge on plant resistance mechanisms and the genes involved. Therefore, a step forward now will be on exploiting natural variations with novel technologies in combination of eco-safe management practices to develop durable insect-resistant pulse crops. Despite technical and regulatory difficulties, developing insect resistance should be the major priority area for future breeding and genetic engineering studies aiming at pulse crop improvement