Drug repurposing for identification of potential inhibitors against SARS-CoV-2 spike receptor-binding domain: An in silico approach.

BACKGROUND & OBJECTIVES: The world is currently under the threat of coronavirus disease 2019 (COVID-19) infection, caused by SARS-CoV-2. The objective of the present investigation was to repurpose the drugs with potential antiviral activity against receptor-binding domain (RBD) of SARS-CoV-2 spike (S) protein among 56 commercially available drugs. Therefore, an integrative computational approach, using molecular docking, quantum chemical calculation and molecular dynamics, was performed to unzip the effective drug-target interactions between RBD and 56 commercially available drugs. METHODS: The present in silico approach was based on information of drugs and experimentally derived crystal structure of RBD of SARS-CoV-2 S protein. Molecular docking analysis was performed for RBD against all 56 reported drugs using AutoDock 4.2 tool to screen the drugs with better potential antiviral activity which were further analysed by other computational tools for repurposing potential drug or drugs for COVID-19 therapeutics. RESULTS: Drugs such as chalcone, grazoprevir, enzaplatovir, dolutegravir, daclatasvir, tideglusib, presatovir, remdesivir and simeprevir were predicted to be potentially effective antiviral drugs against RBD and could have good COVID-19 therapeutic efficacy. Simeprevir displayed the highest binding affinity and reactivity against RBD with the values of -8.52 kcal/mol (binding energy) and 9.254 kcal/mol (band energy gap) among all the 56 drugs under investigation. INTERPRETATION & CONCLUSIONS: In the current investigation, simeprevir was identified as the potential antiviral drug based on the in silico findings in comparison to remdesivir, favipiravir and other 53 drugs. Further, laboratory and clinical investigations are needed to be carried out which will aid in the development of quick therapeutics designed for COVID-19.

Multi-centric evaluation of a stage-specific reverse transcriptase-polymerase chain reaction assay as a xenomonitoring tool for the detection of infective (L3) stage Wuchereria bancrofti in vectors.

Background & objectives: An infective stage specific reverse transcriptase-polymerase chain reaction (RT-PCR) assay utilizing the abundant larval transcript-3 (Alt-3) gene of Wuchereria bancrofti was developed at ICMR-VCRC, Puducherry and found to be stage specific, and sensitive upon validation in the laboratory. This study was aimed at independently evaluating this assay for its utility as a monitoring/surveillance tool in the operational programme for elimination of lymphatic filariasis (LF) by four national research laboratories. Methods: Evaluation of the assay was carried out in a multi-centric mode in three phases. In phase I, a workshop was conducted to impart hands-on training to the scientists from the collaborating centres on the RT-PCR assay and in Phase II the assay was evaluated for specificity and sensitivity in detecting the infective (L3) stage larvae of W. bancrofti in its vector, Culex quinquefasciatus, using 50 coded pooled samples. Phase III evaluation was done on wild-caught mosquito vectors from selected endemic areas of Assam and Bhubaneswar States and Andaman Nicobar islands. Results: Phase I data indicated that the assay was able to detect all the pools of mosquito samples contaning L3 stage larvae of W. bancrofti as positive, even in the presence of other vector stages of the parasite indicating its stage specificity (100%). The assay was found highly sensitive (100%), detecting all the infected pools as positive and specific detecting all uninfected pools as negative. The results of phase II showed inter-laboratory variation. Phase III evaluation from all the centres suggested that the infectivity rate determined for pooled mosquitoes by the RT-PCR assay (0.5%) was comparable to that by dissection method (1.2%) (95% confidence interval overlaps). Interpretation & conclusions: Overall, the results from three of the four participating centres indicated that the assay is at least as sensitive and stage specific as the conventional mosquito dissection technique, and hence, may be useful as a xenomonitoring tool for Transmission Assessment Survey in Mass Drug Administration programmes for LF.

Molecular dynamics insights into the structure, function, and substrate binding mechanism of mucin desulfating sulfatase of gut microbe Bacteroides fragilis.

The complex and dynamic consortia of microbiota that harbors the human gastrointestinal tract contributes ominously to the maintenance of health, the onset and progression of diverse spectrum of disorders. The capability of these enteric microbes to bloom within the gut mucosal milieu is often associated to the glycan metabolism of mucin-degrading bacteria. Accruing evidences suggests that the desulfation of mucin is a rate-limiting step in mucin degradation mechanism by colonic bacterial mucin-desulfating sulfatase enzymes (MDS) enzymes. Till date no experimental evidence is available on how conformational flexibility influences structure and substrate specificity by MDS of gut microbe Bacteroides fragilis. Henceforth, to gain deep insights into the missing but very imperative mechanism, we performed a comprehensive molecular dynamics study, principal component analysis and MM/PBSA binding free energies to gain insights into (i) the domain architecture and mode of substrate binding (ii) conformational dynamics and flexibility that influence the orientation of substrate, (iii) energetic contribution that plays very decisive role to the overall negative binding free energy and stabilities of the complexes (iv) critical residues of active site which influence binding and aid in substrate recognition. This is the first ever report, depicting the molecular basis of recognition of substrates and provides insights into the mode of catalysis by mucin desulfating sulfatase enzymes in gut microbiota. Overall, our study shed new insights into the unmapped molecular mechanisms underlying the recognition of various substrates by mucin desulfating sulfatase, which could be of great relevance in therapeutic implications in human gut microbiota associated disorders.

Molecular docking and simulation study for synthesis of alternative dapsone derivative as a newer antileprosy drug in multidrug therapy.

Leprosy (causative, Mycobacterium leprae) continues to be the persisting public health problem with stable incidence rates, owing to the emergence of dapsone resistance that being the principal drug in the ongoing multidrug therapy. Hence, to overcome the drug resistance, structural modification through medicinal chemistry was used to design newer dapsone derivative(s) (DDs), against folic acid biosynthesis pathway. The approach included theoretical modeling, molecular docking, and molecular dynamic (MD) simulation as well as binding free energy estimation for validation of newly designed seven DDs, before synthesis. Theoretical modeling, docking, and MD simulation studies were used to understand the mode of binding and efficacy of DDs against the wild-type and mutant dihydropteroate synthases (DHPS). Principal component analysis was performed to understand the conformational dynamics of DHPS-DD complexes. Furthermore, the overall stability and negative-binding free energy of DHPS-DD complexes were deciphered using Molecular Mechanics/Poisson-Boltzmann Surface Area technique. Molecular mechanics study revealed that DD3 possesses higher binding free energy than dapsone against mutant DHPS. Energetic contribution analysis portrayed that van der Waals and electrostatic energy contributes profoundly to the overall negative free energy, whereas polar solvation energy opposes the binding. Finally, DD3 was synthesized and characterized using Fourier-transform infrared spectroscopy, UV, liquid chromatography-mass spectrometry, and proton nuclear magnetic resonance techniques. This study suggested that DD3 could be further promoted as newer antileprosy agent. The principles of medicinal chemistry and bioinformatics tools help to locate effective therapeutics to minimize resources and time in current drug development modules.

Identification and characterization of differentially expressed genes from human microglial cell samples infected with Japanese encephalitis virus.

BACKGROUND & OBJECTIVES: Limited studies have been reported on Japanese encephalitis (JE) with reference to microarray data analysis. The present study involved an in silico approach for identification and characterization of differentially expressed genes in human microglial cell (CHME3) samples, infected with P20778 strain of Japanese encephalitis virus (JEV). METHODS: Gene expression data (GSE57330) belonging to mRNA expression profile of CHME3 cells infected with JEV, was downloaded from the gene expression omnibus (GEO) database, processed and normalized by robust multichip averaging (RMA) method using affy packages of R. The Bayes method was used to correct multiple testing. The log fold change (logFC > 1) and p< 0.05 were used as cut-off to identify differentially expressed genes (DEGs). The newly identified hub genes were set at the centre for construction of protein-protein interaction network using search tool for the retrieval of interacting genes/proteins (STRING) database considering human genome as reference. Gene ontology and pathway enrichment analysis of the hub gene and its associated genes were performed using STRING and DAVID tool. RESULTS: Microarray data analysis revealed that STAT1 gene was down-regulated during JEV infection. STAT1 gene was found to interact with tyrosine protein kinase family members, and showed strong interaction with JAK1 and JAK2 genes. INTERPRETATION & CONCLUSION: The identified transcription factors and the binding sites in the promoter region of STAT1 gene might act as potential drug targets in near future.

Development, standardization and validation of molecular techniques for malaria vector species identification, trophic preferences, and detection of Plasmodium falciparum.

BACKGROUND & OBJECTIVES: Knowledge on prevalence of malaria vector species of a certain area provides important information for implementation of appropriate control strategies. The present study describes a rapid method for screening of major Anopheline vector species and at the same time detection of Plasmodium falciparum sporozoite infection and blood meal preferences/trophic preferences. METHODS: The study was carried from February 2012 to March 2013 in three seasons, i.e. rainy, winter and summer in Jhumpura PHC of Keonjhar district, Odisha, India. Processing of mosquitoes was carried out in two different methods, viz. mosquito pool (P1) and mosquito DNA pool (P2). Pool size for both the methods was standardized for DNA isolation and multiplex PCR assay. This PCR based assay was employed to screen the major vector com- position in three different seasons of four different ecotypes of Keonjhar district. Pearson's correlation coefficient was determined for a comparative analysis of the morphological identification with the pool prevalence assay for each ecotype. RESULTS: A pool size of 10 was standardized for DNA isolation as well as PCR. PCR assay revealed that the average pool prevalence for all ecotypes was highest for An. annularis in winter and summer whereas for An. culicifacies it was rainy season. Foothill and plain ecotypes contributed to highest and lowest vectorial abundance respectively. The results of the prevalence of vector species in pool from PCR based assay were found to be highly correlated with that of the results of morphological identification. INTERPRETATION & CONCLUSION: Screening by pool based PCR assay is relatively rapid as compared to conventional identification and can be employed as an important tool in malaria control programmes.

Wolbachia: A biological control strategy against arboviral diseases.

Vector-borne diseases particularly those transmitted by mosquitoes like Dengue are among the leading causes of mortality and morbidity in human population. There are no effective vaccines or treatment against dengue fever till date and the control methods are limited. So, new approaches are urgently in need to reverse these trends. Vector control is currently the primary intervention tool. Strategies that reduce or block pathogen transmission by mosquitoes have been proposed as a means of augmenting current control measures to reduce the growing burden of vector-borne diseases. Wolbachia an endosymbiont of arthropod vectors is being explored as a novel ecofriendly control strategy. Studies in Drosophila have shown that Wolbachia can confer resistance to diverse RNA viruses and protect flies from virus-induced mortality. This review was focused on biology of the Wolbachia and its implication as a control measure for arboviral diseases mainly Dengue and Chikungunya.

The mosquitocidal activity of methanolic extracts of Lantana cramera root and Anacardium occidentale leaf: role of glutathione S-transferase in insecticide resistance.

Larvicidal activity of methanolic plant extracts of Lantana cramera (P1) root and Anacardium occidentale (P2) leaf was investigated against the larvae of the three mosquito species (Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti reared in the laboratory), and the respective glutathione S-transferase (GST) activity was analyzed as an index of protection against the extracts. The LC50 (extract concentration that shows 50% mortality) values of P1 extract for An. stephensi, Ae. aegypti, and Cx. quinquefasciatus were 132.55, 27.82, and 11.68 ppm, respectively, whereas those of P2 extract were 56.81, 912, and 10.79 ppm, respectively. In general, in the untreated groups, the level of GST activity was significantly higher in Ae. aegypti in comparison with An. stephesi and Cx. quinquefasciatus. However, the enzyme activity failed to show any response when treated with either of the plant extracts in Ae. aegypti. However, an increase in the GST activity was recorded in extract-treated larvae of both An. stephensi and Cx. quinquefasciatus. The results of the current study suggest that both the plant extracts show species-specific mosquitocidal potential. Induction of GST activities in survived An. stephensi and Cx. quinquefasciatus larvae suggests the role of this enzyme in conferring resistance to the plant extracts.

Nation-wide vector surveillance on Zika and Dengue did not indicate transmission of the American lineage-pandemic Zika virus in India.

OBJECTIVES: Following the Public Health Emergency of International Concern declared on Zika by the World Health Organization during 2016, the Indian Council of Medical Research carried out nationwide vector surveillance for Zika and Dengue viruses (ZIKV and DENV) in India as a preparedness measure in 2016-19. METHODS: High-risk zones distributed to 49 Districts in 14 states/union territories were included in the study. Seven ICMR institutions participated, following a standard operating protocol. Aedes specimens sampled weekly were processed by multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) for ZIKV/DENV and random samples crosschecked with real-time RT-PCR for ZIKV. RESULTS: Altogether, 79 492 Aedes specimens in 6492 pools were processed; 3 (0.05%) and 63 (0.97%) pools, respectively, were found positive for ZIKV and DENV. ZIKV infections were recorded in Aedes aegypti sampled during the 2018 sporadic Zika outbreak in Jaipur, Rajasthan. However, these belonged to the Asian lineage of the virus, already circulating in the country. Both Ae. aegypti and Aedes albopictus distributed to 8 states/union territories were found to be infected with DENV. Both sexes of Ae. albopictus were infected, indicating transovarial transmission. CONCLUSION: This investigation evinced no active transmission of the American lineage-pandemic Zika virus in India during the pandemic period.

Distribution of sibling species of Anopheles culicifacies s.l. and Anopheles fluviatilis s.l. and their vectorial capacity in eight different malaria endemic districts of Orissa, India.

The study was undertaken in eight endemic districts of Orissa, India, to find the members of the species complexes of Anopheles culicifacies and Anopheles fluviatilis and their distribution patterns. The study area included six forested districts (Keonjhar, Angul, Dhenkanal, Ganjam, Nayagarh and Khurda) and two non-forested coastal districts (Puri and Jagatsingpur) studied over a period of two years (June 2007-May 2009). An. culicifacies A, B, C and D and An. fluviatilis S and T sibling species were reported. The prevalence of An. culicifacies A ranged from 4.2-8.41%, B from 54.96-76.92%, C from 23.08-33.62% and D from 1.85-5.94% (D was reported for the first time in Orissa, except for occurrences in the Khurda and Nayagarh districts). The anthropophilic indices (AI) were 3.2-4.8%, 0.5-1.7%, 0.7-1.37% and 0.91-1.35% for A, B, C and D, respectively, whereas the sporozoite rates (SR) were 0.49-0.54%, 0%, 0.28-0.37% and 0.41-0.46% for A, B, C and D, respectively. An. fluviatilis showed a similarly varied distribution pattern in which S was predominant (84.3% overall); its AI and SR values ranged from 60.7-90.4% and 1.2-2.32%, respectively. The study observed that the co-existence of potential vector sibling species of An. culicifacies (A, C and D) and An. fluviatilis S (> 50%) was responsible for the high endemicity of malaria in forested districts such as Dhenkanal, Keonjhar, Angul, Ganjam, Nayagarh and Khurda (> 5% slide positivity rate). Thus, the epidemiological scenario for malaria is dependent on the distribution of the vector sibling species and their vectorial capacity.

Vectorial role of Anopheles subpictus Grassi and Anopheles culicifacies Giles in Angul District, Orissa, India.

Malaria transmission by Anopheles subpictus Grassi, 1899 and Anopheles culicifacies Giles, 1901 was studied from March 2004 to February 2007 in Angul District, Orissa, India, which is highly endemic for malaria. Adult mosquitoes were collected from human dwellings using sucking tubes and a mechanical aspirator. After identification, some An. subpictus and An. culicifacies specimens were subjected to a precipitin test to determine their anthropophilic index and the remaining samples were preserved in isopropyl alcohol for sporozoite detection by nested PCR. An. subpictus was the most prevalent (29.0%) anopheline species detected, followed by An. culicifacies (11.6%). The anthropophilic index for the An. subpictus was higher than An. culicifacies and was highest during the summer season. Malaria sporozoite rates of 0.52% and 1.82% were detected for An. subpictus and An. culicifacies, respectively. Sporozoites were detected during the summer in An. subpictus and during the rainy season and winter in An. culicifacies. The slide positivity rate (SPR) was high during the summer. The high anthropophilic index and presence of sporozoites in An. subpictus during the summer indicate An. subpictus is a contributory factor for the high SPR during the summer, and An. culicifacies is a contributory factor for the high SPR during the rainy and winter seasons, along with other anophelines. In the present study An. subpictus has been incriminated as a vector of malaria for the first time in Orissa.

Hedychium coronarium extract arrests cell cycle progression, induces apoptosis, and impairs migration and invasion in HeLa cervical cancer cells.

BACKGROUND: Hedychium coronarium Koen. (Zingiberaceae) is traditionally used as medicine in countries such as India, China, and Vietnam for treatment of various ailments including cancer. However, in spite of its implied significance in cancer treatment regimes, there are no reports so far involving the anticancerous attributes of H, coronarium ethanol extract (HCEE) on cancer cells and a more comprehensive study on its mechanism is still lacking. MATERIALS AND METHODS: The cytotoxicity of HCEE was evaluated by MTT and clonogenic survival assay. Annexin V/propidium iodide (PI), Hoechst 33342 staining, and TUNEL assay were performed to detect apoptosis. Cell cycle analysis was performed using PI staining. JC-1 and 2',7'-dichlorodihydrofluorescein diacetate assay were used to check the levels of MMP and ROS, respectively. Western blot analysis was carried out to measure the expression levels of proteins. Migration and invasion activity were assessed by wound healing and Transwell membrane assay, respectively. RESULTS: Antiproliferative effect of HCEE was investigated in various cancerous and normal cell lines. Among these, HCEE significantly inhibited the survival of HeLa cells without affecting the viability of normal human umbilical vein endothelial cells. Annexin V/PI, Hoechst staining, and TUNEL assay showed HCEE induced apoptosis in HeLa cells in a dose-dependent manner. HCEE promoted cell cycle arrest at G1 phase in HeLa cells by upregulating the levels of p53 and p21 and downregulating the levels of cyclin D1, CDK-4, and CDK-6. Moreover, HCEE treatment upregulated the expression of Bax and downregulated the expression of Bcl-2. Additionally, HCEE activated the caspase cascade by increasing the activities of caspase-9, caspase-8, and caspase-3. The expression levels of Fas ligand and Fas were also upregulated. Further, HCEE inhibited the migratory potential of HeLa cells by downregulating MMP-2 and MMP-9 expression levels. CONCLUSION: Our results indicate H. coronarium exerts antiproliferative and apoptotic effects against HeLa cells, and therefore may be used for treatment against cervical cancer.

Structural dynamics of Casein Kinase I (CKI) from malarial parasite Plasmodium falciparum (Isolate 3D7): Insights from theoretical modelling and molecular simulations.

The protein kinases (PKs), belonging to serine/threonine kinase (STKs), are important drug targets for a wide spectrum of diseases in human. Among protein kinases, the Casein Kinases (CKs) are vastly expanded in various organisms, where, the malarial parasite Plasmodium falciparum possesses a single member i.e., PfCKI, which can phosphorylate various proteins in parasite extracts in vitro condition. But, the structure-function relationship of PfCKI and dynamics of ATP binding is yet to be understood. Henceforth, an attempt was made to study the dynamics, stability, and ATP binding mechanisms of PfCKI through computational modelling, docking, molecular dynamics (MD) simulations, and MM/PBSA binding free energy estimation. Bi-lobed catalytic domain of PfCKI shares a high degree of secondary structure topology with CKI domains of rice, human, and mouse indicating co-evolution of these kinases. Molecular docking study revealed that ATP binds to the active site where the glycine-rich ATP-binding motif (G16-X-G18-X-X-G21) along with few conserved residues plays a crucial role maintaining stability of the complex. Structural superposition of PfCKI with close structural homologs depicted that the location and length of important loops are different, indicating the dynamic properties of these loops among CKIs, which is consistent with principal component analysis (PCA). PCA displayed that the overall global motion of ATP-bound form is comparatively higher than that of apo form. The present study provides insights into the structural features of PfCKI, which could contribute towards further understanding of related protein structures, dynamics of catalysis and phosphorylation mechanism in these important STKs from malarial parasite in near future.

Novel Insights into the Molecular Interaction of a Panduratin A Derivative with the Non Structural Protein (NS3) of Dengue Serotypes: A Molecular Dynamics Study.

BACKGROUND: The ligand PKP10 having substitution of Cl- at R2 and R3 positions of ring A of Panduratin A i.e., ((1R,2S,5S)-5-(2,3-dichlorophenyl)-3-methyl-2-(3-methylbut-2-nyl)cyclohex-3- enyl)(2,6-dihydroxy-4-methylphenyl)methanone hydrate) has been observed to block the Nuclear Receptor Binding Protein binding site of Non Structural protein 3 in all dengue serotypes. In continuation with our earlier study, we have reported sixty novel Panduratin A derivatives compounds where substitution was done in positions 2 and 3 position of the benzyl ring A of Panduratin A with various substituents. METHODS: We selected ((1R,2S,5S)-5-(2,3-dichlorophenyl)-3-methyl-2-(3-methylbut-2-nyl)cyclohex-3- nyl) (2,6-dihydroxy-4-methylphenyl) methanone hydrate) (PKP10) for molecular dynamics (MD) simulations as it constantly produced lowest CDocker interaction energy of among all the sixty five derivatives. The CDocker interaction energy was predicted to be -140.804, -79.807, -78.217 and -84.073 Kcalmol-1 respectively against NS3 protein of dengue serotypes (DENV1-4). To understand the dynamics of the PKP10 with NS3 protein, each complex was subjected to molecular dynamics simulations of 50 ns in aqueous solution. MD (Molecular Dynamics) simulation study revealed that the binding of ligand PKP10 at the active site of NS3 induces a conformational change in all serotypes which was well supported by principal component analysis. RESULT: To the best of our knowledge, this is first ever study which provided atomistic insights into the interaction of PKP10 with NS3 protein of dengue serotypes. CONCLUSION: The result from our study along with in vitro studies is expected to open up better avenues to develop inhibitors for dengue virus in the near future.

A shift in resting habitat and feeding behavior of Anopheles fluviatilis sibling species in the Keonjhar district of Odisha, India.

BACKGROUND: Anopheles fluviatilis exists as a complex of sibling species S, T, U and V exhibiting distinct variations. Sibling species S is considered as the main vector and anthropogenic whereas T, U and V are zoophagic non-vectors. This study was performed in a forested village of Keonjhar district, Odisha to identify the status of An. fluviatilis sibling species. METHODS: Mosquito collections were made from cattle sheds (CS), human dwellings (HD) and mixed dwellings (MD) from June 2012 to May 2013. The proportion of An. fluviatilis collected from different habitats was compared with An. culicifacies. PCR assays were conducted to reveal their sibling species composition, host preference and sporozoite rate. RESULTS: Anopheles fluviatilis was the dominant species followed by An. culicifacies. The relative proportion of collection was high in MD and HD for An. fluviatilis and An. culicifacies respectively. PCR assay confirmed 9.4% S and 75.5% T. Mean collection of sibling species T and S were significantly high in MD and HD. Human blood index (HBI) of 0.88 and 0.61 was confirmed for sibling species S and T respectively with 13% sporozoite rate for S. CONCLUSIONS: High density of the sibling T was found in the study site with a shift in resting habitat and blood feeding preference. GenBank submissions: KJ451071.1, KJ451072.1, KJ451073.1, KJ451074.1, KJ451432.1, KJ451433.1, KJ451434.1, KJ451435.1, KJ451428.1, KJ451429.1, KJ451430.1, KJ451431.1.

Vectorial capacity and genetic diversity of Anopheles annularis (Diptera: Culicidae) mosquitoes in Odisha, India from 2009 to 2011.

Anopheles annularis is one of the major vectors of malaria in Odisha, India. The present study was undertaken to determine the vectorial capacity and assess the genetic diversity of An. annularis collected from different endemic regions of Odisha. Mosquitoes were collected from thirteen endemic districts using standard entomological collection methods from 2009 to 2011. Sibling species of An. annularis were identified by PCR-RFLP and sequencing of D3 region of 28S ribosomal DNA (rDNA) region. Plasmodium falciparum (Pf) sporozoite rate and human blood fed percentage (HBF) were estimated by multiplex PCR using Pf and human specific primers. Genetic diversity of An. annularis was estimated by ISSR markers. Out of 1647 An. annularis collected, 1353 (82.15%) were collected by mechanical aspirators and 294 (17.85%) by light trap. 49 (2.97%) were positive for human blood and 18 (1.09%) were positive for Pf sporozoite. PCR-RFLP and sequencing analyses detected only An annularis A in the study areas. Overall genetic differentiation among An. annularis populations was moderate (FST=0.048) and showed significant correlation between genetic distance and geographic distance (r=0.882; P<0.05). Angul population proved to be genetically unique and was highly divergent FST>0.110) from other populations, suggesting low gene flow between them. The study indicated that only An. annularis A was found in Odisha with potential vectorial capacity that can play a major role in malaria transmission. ISSR markers proved to be useful molecular tools to evaluate genetic variability in An. annularis populations.

Molecular identification and phylogeny of Myzomyia and Neocellia series of Anopheles subgenus Cellia (Diptera: Culicidae).

Any biological study is only meaningful if the concerned organism is accurately identified; this is particularly important in vector-borne disease studies where correct and precise identification of the target species has medical and practical implications, such as in vector control. The Myzomyia series is divided into four groups including the Funestus group, which consists of five subgroups, i.e. Aconitus, Culicifacies, Funestus, Minimus, Rivulorum, and the Neocellia series, which is divided into three groups Annularis, Jamesii and Maculatus. Members of the Funestus group of Myzomyia and the Annularis group of the Neocellia series are difficult to identify because of the morphological overlap that exists within the groups. Therefore a multiplex polymerase chain reaction (PCR) assay was developed based on the sequence of the D3 region of 28S rDNA to distinguish between four members (An. fluviatilis, An. culicifacies, An. varuna and An. aconitus) of three subgroups (Minimus, Aconitus, Culicifacies) of the Funestus group of Myzomyia and three members (An. annularis, An. pallidus and An. philippinensis) of the Annularis group of the Neocellia series of the Anopheles subgenus Cellia, prevalent in Orissa, India. Polymorphism present on the D3 region of rDNA allowed the development of a species-specific primer that when combined with two universal primers lead to a simple and sensitive multiplex allele-specific polymerase chain reaction (AS-PCR) assay. This assay can be applied as an unbiased confirmatory method for the identification of morphological variants, imperfectly preserved specimens and life stages for which taxonomic keys do not allow a definitive species determination. Finally, phylogenetic relationships between the members of the two series were determined using D3 sequence data. The phylogenetic relationships inferred from maximum parsimony and the neighbour joining analysis separated two distinct monophyletic clades, one consisting of species of Myzomyia and other of species of the Neocellia series. The molecular phylogeny obtained in this work matches with that of the classical morphological taxonomy reasonably well, with proper species arrangements.

A unique methodology for detecting the spread of chloroquine-resistant strains of Plasmodium falciparum, in previously unreported areas, by analyzing anophelines of malaria endemic zones of Orissa, India.

Generally, clinical data is referred to study drug-resistance patterns of Plasmodium falciparum in an area. This is only possible after a clear manifestation of drug-resistance parasites inside the human host, and thereafter detection by healthcare persons. The detection of spread of drug-resistant P. falciparum in a population, before any pathological symptoms detected in humans is possible by analyzing the anopheline vectors, transmitting malaria. In the present study we implemented a new strategy to detect the spread of chloroquine-resistant (CQR) strains of P. falciparum by the major malaria vectors prevalent in selected endemic regions of Orissa, India. We screened P. falciparum positive vectors by using polymerase chain reaction (PCR)-based assay and thereafter detected K76T mutation in the Pfcrt gene, the chloroquine-resistance marker, of parasites present within the vectors. This study showed higher transmission rate of chloroquine-resistant P. falciparum parasites by Anopheles culicifacies and Anopheles fluviatilis. This study will help in assigning chloroquine-resistant P. falciparum sporozoite transmission potential of malaria vectors and suggest that by adopting the mentioned methodologies, we can detect the spreading of the drug-resistant P. falciparum in its transmission. This approach of studying the anophelines during regular vector collection and epidemiological analysis will give the knowledge of chloroquine-resistance pattern of P. falciparum of an area and help in devising effective malaria control strategy.

The development and evaluation of a single step multiplex PCR for simultaneous detection of Anopheles annularis group mosquitoes, human host preference and Plasmodium falciparum sporozoite presence.

The Anopheles annularis group mosquitoes, subgenus Cellia Theobald (Diptera: Culicidae), includes five recognized species: An. annularis Van der Wulp, An. nivipes Theobald, An. pallidus Theobald, An. philippinensis Ludlow and An. schueffneri Stanton. From these five, the three most common species found in Orissa were considered for this study because of their remarkable vectorial and behavioral variation and the important role they play in malaria transmission. To identify and understand their role in malaria transmission we developed a single multiplex PCR-based assay. This assay included the detection of human blood feeding habit and Plasmodium falciparum sporozoite presence. Of the 186 An. annularis mosquitoes collected, morphological character-based identification showed that 94 were An. annularis, 54 were An. philippinensis and 38 were An. pallidus. However, the multiplex PCR assay confirmed that 91 were An. annularis, 56 were An. philippinensis and 39 were An. pallidus individuals after adjustments were made for misidentified specimens in the morphological method. Anopheles annularis and An. philippinensis were found positive for human blood, and two samples of An. annularis species were positive for P. falciparum sporozoites. This one-step PCR-based method constitutes a very powerful tool in large surveys of anopheline populations.

Distribution of sibling species of Anopheles culicifacies s.l. and Anopheles fluviatilis s.l. and their vectorial capacity in eight different malaria endemic districts of Orissa, India

The study was undertaken in eight endemic districts of Orissa, India, to find the members of the species complexes of Anopheles culicifacies and Anopheles fluviatilis and their distribution patterns. The study area included six forested districts (Keonjhar, Angul, Dhenkanal, Ganjam, Nayagarh and Khurda) and two non-forested coastal districts (Puri and Jagatsingpur) studied over a period of two years (June 2007-May 2009). An. culicifacies A, B, C and D and An. fluviatilis S and T sibling species were reported. The prevalence of An. culicifacies A ranged from 4.2-8.41 percent, B from 54.96-76.92 percent, C from 23.08-33.62 percent and D from 1.85-5.94 percent (D was reported for the first time in Orissa, except for occurrences in the Khurda and Nayagarh districts). The anthropophilic indices (AI) were 3.2-4.8 percent, 0.5-1.7 percent, 0.7-1.37 percent and 0.91-1.35 percent for A, B, C and D, respectively, whereas the sporozoite rates (SR) were 0.49-0.54 percent, 0 percent, 0.28-0.37 percent and 0.41-0.46 percent for A, B, C and D, respectively. An. fluviatilis showed a similarly varied distribution pattern in which S was predominant (84.3 percent overall); its AI and SR values ranged from 60.7-90.4 percent and 1.2-2.32 percent, respectively. The study observed that the co-existence of potential vector sibling species of An. culicifacies (A, C and D) and An. fluviatilis S (> 50 percent) was responsible for the high endemicity of malaria in forested districts such as Dhenkanal, Keonjhar, Angul, Ganjam, Nayagarh and Khurda (> 5 percent slide positivity rate). Thus, the epidemiological scenario for malaria is dependent on the distribution of the vector sibling species and their vectorial capacity.