Reji Gopalakrishnan

Phylogenetic Characterization of a Novel Insect-Specific Flavivirus Detected in a Culex Pool, Collected from Assam, India

Objective: We report the phylogenetic characterization of a unique flavivirus sequence detected in a wild Culex tritaeniorhynchus mosquito pool, collected from the northeast Indian state of Assam. Methods: DNA and RNA were extracted from field-collected mosquito pools. Extracts were subjected to PCR and reverse transcriptase PCR amplification using universal and type-specific primers for direct detection of flavivirus-specific viral nucleic acids. An amplified flavivirus nonstructural protein 5 (NS5) genetic region was sequenced and BLAST searched, and phylogenetic analyses performed with reference sequences retrieved from GenBank. Results: Phylogenetic analyses revealed the sequence to be related to insect-specific flaviviruses (ISFs) of the genus Flavivirus, family Flaviviridae. Despite being related to the Palm Creek virus (PCV; an ISF very recently reported from Northern Australia), the present sequence (provisionally named Assam virus) was found to be highly divergent from PCV and other ISF sequences available in GenBank. The partial NS5 sequence analysis demonstrated low nucleotide sequence identity (66-77%) with known ISFs reported from other parts of the globe. Conclusion: Findings of this study suggest the presence of a candidate novel ISF - the first to be reported from India.

Herbal Insecticides, Repellents and Biomedicines: Effectiveness and Commercialization

This book looks closely at herbal product development and commercialisation. In spite of an ever-growing demand, there is a dearth of safe and effective herbal products that meet consumers expectations. Therefore, this book takes it upon itself to elaborate on the development process of herbal insecticides, repellents and biomedicines from a commercialisation point of view. The introductory chapters deal with the various strategies for disease vector control and provide an overview of herbal biomedicines. The subsequent chapter describes plants with mosquito larvicidal activity, including a comprehensive list of lethal concentrations against different mosquito species. The chapter on Himalayan plants discusses potential botanical insecticide sources and their chemical constituents before delving into the topic of natural insecticides of microbial origin and their efficacy against mosquitoes. Plant-derived insecticides belonging to different chemical classes and the extraction, purification and characterisation of bioactive compounds are illustrated, as well. The recent technological advances in the formulation of microbial, biochemical and botanical insecticides are also reviewed. Three chapters focus on important medicinal plants useful for treating human ailments, with special reference to the traditional healing practices of northeastern India. This is followed by a chapter on the production, use and safety of biopharmaceuticals and edible, plant-based vaccines. The intellectual property issues related to herbal products in India including patents, trademarks, geographical indications, trade secrets and traditional knowledge resources are plainly examined. The book ends with a chapter on the herbal product registration process in India, wherein the data requirements for registration, clinical efficacy trials, toxicity studies, quality control, packaging and labelling are clearly explained. In conclusion, this book is a step-by-step guide for the development of safe, effective and commercially viable herbal insecticides, repellents and biomedicines

Rebound of Cotton leaf curl Multan virus and its exclusive detection in cotton leaf curl disease outbreak, Punjab (India), 2015

Cotton leaf curl disease (CLCuD) outbreaks caused by CLCuD associated begomoviruses (CABs) significantly constrain cotton production in India and Pakistan. In comparison to the CABs circulating in Pakistan, molecular epidemiology, evolution and recombination patterns of CABs circulating in India are less studied. In this work, we characterized CAB complex sequences obtained from the most recent outbreak (Punjab, India, 2015), and rigorously analyzed them with reference to GenBank sequences, submitted from India, Pakistan and other neighbouring countries, using contemporary bioinformatics approaches. In this manuscript, we illustrate the detection of a recombinant, phylogenetically distinct clade of Cotton leaf curl Multan virus (CLCuMuV), suggesting rebound of CLCuMuV in this region. Interestingly, we could not detect Cotton leaf curl Kokhran virus-Burewala strain (CLCuKoV-Bu), which was prevalent in this region, until now. Our study thus indicates substitution of the ‘virulent resistance breaking’ CLCuKoV-Bu by the re-emerging CLCuMuV recombinants. Our findings corroborate with that of a very recent study from Pakistan and we here discuss epidemiological links between the CAB complexes reported in these two studies. Taken together, these observations signify a shifting epidemiology of CABs, and seem to correlate with the recent prediction of the ‘third epidemic’ of CLCuD in the Indian subcontinent.

Mosquito Biodiversity of Northeastern India

Northeastern India is a hotspot of biodiversity and there is enormous diversity in the insect fauna recorded from the region. This includes haematophagous or blood sucking insects such as mosquitoes, black flies, sand flies and tabanids. Mosquitoes are important from the public health point of view since they are the vectors of human diseases such as malaria, dengue, chikungunya, filariasis and Japanese encephalitis. Proper identification and recording of the vector species is of utmost importance as it helps in understanding the habitats and bionomics of the target species. The oriental region, which includes India, is regarded as one of the richest biogeographic regions for mosquitoes of the world. The chapter focuses on the diversity of mosquitoes in the northeastern region of India. The chapter is not intended to serve as a checklist of the entire mosquito species recorded but attempts to give only an overview of the mosquito diversity. Such a description would help in understanding and appreciating the tremendous insect biodiversity in the region through mosquitoes, which are arguably the most economically important insects. The information on the prevalence, density, diversity and distribution of mosquitoes in the region assumes great significance in the context of management of mosquito borne diseases.

Extraction, Purification and Characterisation of Insecticidal Compounds from Plants

In recent times, a global concern has been raised against the utility of synthetic insecticides in households and fields. Many of such synthetic insecticides were banned in due course of time because of their toxicity to the nontarget flora and fauna. In the quest of developing sustainable and environment-friendly commercial products, different plant components have been studied extensively. Although there are many reports on the insecticidal potential of plant-based compounds, very few reports describe the actual active component responsible for such efficacy. Lack of adequate information on the bioactive compounds creates major challenges for the commercialisation of plant-derived products for pest control. The chapter describes the different classes of plant-derived insecticidal compounds such as alkaloids, flavonoids and terpenoids. The qualitative and quantitative studies of plant compounds need vast expertise in isolation and characterisation methods. The development of chromatographic and spectrometric tools eased the extraction of plant active components. The different techniques involved in the extraction, purification and characterisation of insecticidal compounds extracted from plants along with some salient examples available in the literature are discussed. This chapter may be helpful to construct a bridge between the biologists and chemists to work together in collaboration for elucidating the actual structure and activity of plant-based compounds, which have very significant insecticidal property.