Biology subjects

De, T. D.

Publications and source records attributed to De, T. D..

8 recordsLinked to original sources

bioRxiv2026

Association between breeding-habitat bacterial communities and oviposition behavior of Aedes aegypti: Insights from arboviral outbreak-affected areas of Pune, Western India

Aedes aegypti, an important vector of several arboviral diseases, is highly adapted to human-associated environments and commonly exploits anthropogenic water-holding containers for breeding. Understanding the ecological factors governing oviposition-site selection is essential for developing sustainable vector control strategies. Previous studies have established that microbial communities in breeding waters influence mosquito oviposition-site selection through the production of volatile organic compounds. Importantly, rapid urbanization in India has increased the availability of artificial breeding habitats for Ae. aegypti, potentially facilitating the transmission and persistence of arboviral diseases. However, the composition of bacterial communities in these larval habitats and their potential role in shaping the oviposition behavior of Ae. aegypti remain poorly characterized in the Indian context. Here, we investigated the bacterial diversity and community composition of Aedes larval habitats during the 2024 Zika and chikungunya outbreaks in Pune, India. Water samples, collected from artificial urban containers and natural freshwater habitats, were subjected to 16S rRNA amplicon sequencing. Artificial breeding habitats exhibited significantly higher bacterial diversity and were enriched with Enterobacter spp. compared with natural habitats. Oviposition bioassays further demonstrated a strong preference of gravid Ae. aegypti females for Enterobacter-conditioned water. GCMS analysis of bacterial suspension identified indole as a prominent volatile metabolite associated with Enterobacter, suggesting its possible role in mediating oviposition site selection. Together, these findings provide insights into the microbial and chemical ecology of Ae. aegypti breeding habitats and establish a basis for investigating microbial volatile cues as potential targets for vector surveillance and environmentally sustainable attract-and-kill strategies.

genomics↗

bioRxiv2026

A Poly(rC)-Binding Protein Mediates Iron Delivery to Ferritin in Anopheles stephensi

Iron homeostasis is essential for both the Plasmodium parasite and its hosts, the mosquito and human; however, the molecular mechanisms governing intracellular iron trafficking remain poorly understood. In mammals, poly(rC)-binding proteins (PCBPs) function as major iron chaperones by delivering Fe2+ to ferritin and other iron-dependent proteins, yet their role in insects has not been investigated. Here, we provide the first structural and functional characterization of the PCBP from a major malaria vector, Anopheles stephensi. Comparative structural and evolutionary analyses showed that insect PCBPs are most closely related to human PCBP3. Coordinated expression and co-localization of AsPCBP with ferritin following blood feeding suggested a conserved role in mosquito iron homeostasis. Functional analyses demonstrated that KH2-KH3 linker and KH3 domain of PCBP, plays an important role in the AsPCBP-ferritin interaction and that deletion of these regions, unexpectedly increased ferritin binding affinity but impaired iron delivery, indicating that these regions are dispensable for complex formation but essential for efficient iron transfer. Collectively, our results identify PCBP as a key component of mosquito iron homeostasis that could be exploited for the development of novel antimalarial strategies.

biochemistry↗

bioRxiv2025

Sensory Appendage Protein triggers alarm to pyrethroid in Indian malarial vector Anopheles culicifacies

Sensory appendage proteins (SAPs) serve as molecular arms of odorant-binding protein family members and mediate chemical communication from the external to the internal environment of the insect body. We recently reported that SAP members might have an important role in blood-feeding and/or insecticide resistance-associated behavioral physiologies, but the mechanism remains unclear. Here we show how SAP contributes (i) to the host attraction during navigation for blood-feeding, and (ii) triggers an alert via integrated actions of eyes and peripheral sensory organs to circumvent the toxic effect of insecticide in the susceptible strain of An. culicifacies. Among the six identified SAP members, AcSAP1 and AcSAP2 are abundantly expressed in the olfactory and legs, and their expression is significantly modulated at night in naive adult female mosquitoes. We noticed that AcSAP1 silencing significantly impairs the host-attraction properties of the mosquitoes. Its strong binding affinity to the synthetic pyrethroid prompted us to evaluate the AcSAP1 response to insecticide exposure. Confocal microscopy and molecular profiling data reveal a heightened modulation in the expression of AcSAP1 in eyes, and other peripheral sensory organs including the olfactory (****p<0.00001), legs (**p < 0.004), wings (***p < 0.0004). These findings collectively suggest a crucial role of AcSAP1 in facilitating mosquito navigation, and/or insecticide avoidance. Unraveling the basis of SAP interactions with peripheral sensory systems could pave the way for the development of novel vector control tools.

animal behavior and cognition↗

bioRxiv2023

Circadian oscillation of perireceptor events influence olfactory sensitivity in diurnal and nocturnal mosquitoes

Olfaction and circadian rhythm gate different behaviors in mosquitoes that are important for their capacity to transmit disease. However, the mechanisms of odor detection, and the circadian-guided changes in olfactory sensitivity across different mosquito species, remain largely unexplored. To this end, we performed a circadian-dependent RNA-sequencing study of the peripheral olfactory- and brain tissues of female Anopheles culicifacies and Aedes aegypti mosquitoes. Data analysis revealed a significant upregulation of genes encoding: (a) odorant binding proteins (OBPs), required for transportation of odorant molecules towards the olfactory receptors, and (b) xenobiotic-metabolizing enzymes (XMEs) during the day time in Aedes aegypti and during the dusk-transition phase in Anopheles culicifacies. While XMEs primarily function in the elimination of toxic xenobiotics, concurrent elevation of XMEs and OBPs are hypothesized to act cumulatively to regulate perireceptor events and odorant sensitivity. Electroantennographic analysis with both Anopheles gambiae and Aedes aegypti against diverse behaviorally relevant odorants, combined with XMEs inhibitors and RNA interference, establish the proof-of-concept that XMEs function in perireceptor events during odorant detection and influence the odorant sensitivity in mosquitoes. Additionally, the RNA-sequencing and RNAi-mediated knockdown data revealed that daily temporal modulation of neuronal serine proteases may facilitate the consolidation of the brain function, and influence the odor detection process in both diurnal and nocturnal mosquitoes. These findings provide the impetus to further explore the species-specific rhythmic expression pattern of the neuro-olfactory encoded molecular factors, which could pave the way to develop and implement successful mosquito control methods. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/563057v1_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@181b845org.highwire.dtl.DTLVardef@168f22dorg.highwire.dtl.DTLVardef@f3994aorg.highwire.dtl.DTLVardef@d4fc06_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LICircadian oscillation of perireceptor proteins possibly influences time-of-day dependent change olfactory sensitivity in diurnal and nocturnal mosquitoes C_LIO_LIDiurnal and nocturnal mosquitoes depict distinct dynamic change in perireceptor proteins C_LIO_LIInhibition of cytochrome P450 gene minimizes antennal response to different odorants C_LIO_LINeuronal serine protease may consolidate brain function and odor detection C_LI

molecular biology↗

bioRxiv2021

Functional disruption of Transferrin expression alters reproductive physiologyin Anopheles culicifacies

Iron metabolism is crucial to maintain optimal physiological homeostasis of every organism and any alteration of the iron concentration (i.e. deficit or excess) can have adverse consequences. Transferrins are glycoproteins that play important role in iron transportation and have been widely characterized in vertebrates, and insects, but poorly studied in blood-feeding mosquitoes. Here, we characterized a 2102 bp long transcript AcTrf1a encoding putative transferrin homolog protein from mosquito An. culicifacies. A detailed in silico analysis predicts AcTrf1a (ACUA023913-RA) encodes 624 amino acid (aa) long polypeptide that carries transferrin domain. AcTrf1a also showed a putative N-linked glycosylation site, a characteristic feature of most of the mammalian transferrins and certain non-blood feeding insects. Structure modelling prediction confers the presence of an iron binding site at the N-terminal lobe of the transferrin. Our spatial and temporal expression analysis under altered pathophysiological conditions showed that AcTrf1a abundantly express in the fat-body, ovary, and its response is significantly altered (enhanced) after blood meal uptake, and exogenous bacterial challenge. Additionally, a non-heme iron supplementation of FeCl3 at 1 mM concentration not only augmented the AcTrf1a transcript expression in fat-body, also enhanced the reproductive fecundity of gravid adult female mosquitoes. RNAi mediated knockdown of AcTrf1a causes a significant reduction in the egg laying/fecundity, confirmed important role of transferrin in oocyte maturation. Further detailed characterization may help to select this transcript as a unique target to impair the mosquito reproductive outcome. HighlightsO_LIInsect transferrins are mostly glycoprotein of about 60-80 kDa molecular weight, involved in myriad physiological events and serve as a major iron transport protein. C_LIO_LIHere, we identified and characterized a 2102 bp long transcript encoding putative transferrin homolog of 624 aa long peptide, carrying only one fully functional transferrin domain at N-terminal from An. culicifacies. C_LIO_LISpatial and temporal expression analysis of AcTrf1a highlights an enriched expression in fat-body and ovary during vitellogenesis. C_LIO_LIIron supplementation and dsRNA mediated knockdown experiments together confer that AcTrf1a may have key role in the iron homeostasis regulation during oogenesis, and egg maturation in the gravid female mosquitoes. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=87 SRC="FIGDIR/small/448311v1_fig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@a87ec0org.highwire.dtl.DTLVardef@197cecorg.highwire.dtl.DTLVardef@1588092org.highwire.dtl.DTLVardef@16110b4_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig 1:C_FLOATNO Schematic presentation of iron transport from midgut to ovary by transferrin1 and oocyte reduction after AcTrf1a knockdown. Mosquito acquires iron either from blood meal or iron supplementation in sugar meal. Fat-body derived transferrin proceed towards the gut surface, load iron in its N-terminal iron-binding pocket and deliver iron to ovary. This blood meal iron is required by adult female for completion of gonotrophic cycle. (a) limited iron availability in sugar meal does not support the ovary development and hence no oogenesis; (b) when sugar meal is replaced by blood meal upregulation of transferrin protein results in rapid iron transport to various organs including ovary results in healthy ovarian growth; (c) RNAi mediated knockdown of this transporter protein transferrin in fat-body followed by blood meal, may cause reduced iron transport to ovary and consequently declines in oocyte load. C_FIG

molecular biology↗

bioRxiv2019

Genetic changes of P. vivax tempers host tissue-specific responses in Anopheles stephensi

In our preceding study (Sharma et al., 2019; BioRxiv) we showed that in the gut lumen Plasmodium vivax follows a unique strategy of immuno-suppression by disabling gut flora proliferation. Here, we further demonstrate that post gut invasion, a shrewd molecular relationship with individual tissues such as midgut, hemocyte, salivary glands, and strategic changes in the genetic makeup of P. vivax favors its survival in the mosquito host. A transient suppression of metabolic machinery by early oocysts, and increased immunity against late oocysts suggested a unique mechanism of gut homeostasis restoration and Plasmodium population regulation. Though a hyper immune response of hemocyte was a key to remove free circulating sporozoites, but a strong suppression of salivary metabolic activities, may favor successful survival of invaded sporozoites. Finally, genetic alteration of P. vivax ensures evasion of mosquito responses. Conclusively, our system-wide RNAseq analysis provides first genetic evidences of direct mosquito-Plasmodium interaction and establishes a functional correlation.\n\nAuthor SummaryMalaria transmission dynamics is heavily influenced by mosquito -parasite interaction. When passing through tissue specific barriers, Plasmodium have to compromise by losing its own population, but genetic relation is unknown. To win the developmental race Plasmodium need to overcome two important immuno-physiological barriers. First one accounts an indirect 24-30hr long pre-invasive gut-microbe-parasite interaction in the gut lumen. And second one follows a direct post gut invasive 14-18 days interaction with midgut, hemocyte and salivary glands. During pre-invasive phase of interaction, we showed Plasmodium vivax follows immuno-suppression strategy by restricting microbial growth in the gut lumen. Here, we demonstrate that switch of parasite from one stage to another stage within mosquito vector is accompanied by genetic changes of parasite. Our data suggests genetic makeup change enables the parasite to manipulate the metabolism of mosquito tissues. This strategy not only clear off multifaceted mosquitos tissue specific immune responses, but also favors Plasmodium own survival and transmission. Comprehending this tissue specific interaction between host and parasite at molecular level could provide new tool to intervene the plasmodium life cycle within vector.

genomics↗

bioRxiv2019

Microbiome-Gut-Brain-Axis communication regulates metabolic switch in the mosquito Anopheles culicifacies

Periodic ingestion of a protein-rich blood meal by adult female mosquitoes causes a drastic metabolic change in their innate physiological status, which is referred to as metabolic switch. Although the down-regulation of olfactory factors is key to restrain host-attraction, how the gut metabolic switch modulates brain functions, and resilience physiological homeostasis remains unexplored. Here, we demonstrate that the protein-rich diet induces mitochondrial function and energy metabolism, possibly shifting the brains engagement to manage organismal homeostasis. A dynamic expression pattern of neuro-signaling and neuro-modulatory genes in both the brain and gut indicates an optimal brain-distant organ communication. Even after decapitation, significant modulation of the neuro-modulator receptor genes as well as quantitative estimation of neurotransmitters (NTs), together confer the guts ability to serve as a second brain. Finally, data on comparative metagenomic analysis and altered NTs dynamics of naive and aseptic mosquitoes provide the initial evidence that gut-endosymbionts are key modulators for the synthesis of major neuroactive molecules. Conclusively, our data establish a new conceptual understanding of microbiome-gut-brain-axis communication in mosquitoes. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=183 SRC="FIGDIR/small/774430v2_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@4fed8corg.highwire.dtl.DTLVardef@17494f3org.highwire.dtl.DTLVardef@df1cd7org.highwire.dtl.DTLVardef@1de7923_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG HighlightsO_LIHighly proteinaceous blood meal uptake causes gut metabolic switch activity in mosquitoes. C_LIO_LIGuts calling shifts the brains administrative function from external communication to inter-organ management. C_LIO_LI Gut, as a Second brain plays a crucial role in the maintenance of physiological homeostasis. C_LIO_LIMetabolic switch and proliferation of symbiotic bacteria establish microbiome-gut-brain axis communication in mosquitoes. C_LI

animal behavior and cognition↗

bioRxiv2019

Altered gut microbiota and immunity defines Plasmodium vivax survival in Anopheles stephensi

Blood feeding-enriched gut-microbiota boosts mosquitoes anti-Plasmodium immunity. Here, we ask how Plasmodium vivax alters microbiota, anti-Plasmodial immunity and impact tripartite Plasmodium-mosquito-microbiota interactions in the gut lumen. Using a metagenomics analysis, we predominantly detect Elizabethkingia meningitis and Pseudomonas sps. in naive mosquitoes. Naive blood fed gut shows a heightened presence of Elizabethkingia, Pseudomonas and Serratia. A parallel RNAseq analysis of blood-fed midguts identify Elizabethkingia-transcripts, which may have role in iron metabolism. Post, a Plasmodium vivax infected blood-meal, however, we do not detect bacterial until circa 36 hours. Intriguingly, transcriptional expression of a selected array of antimicrobial arsenal cecropins 1-2, defensin-1 and gambicin remains low during the first 36 hours-a time frame when ookinietes/early oocysts invade gut. We conclude during the preinvasive phase, Plasmodium vivax outcompetes midgut-microbiota. Suppression of important immune factors, likely due to altered microbiota, may enhance Plasmodium vivax survival. Additional finding of a novel Wolbachia association warrants further research to design paratransgenesis tools for malaria control.\n\nAuthor SummarySuccessful malaria transmission relies on the competitive interactions of Plasmodium and mosquitos tissue specific immune potential. Within 24hrs of blood meal gut-microbiota grows exponentially and lead to robust enhancement of mosquito immune response, which is detrimental to parasite survival and development. But the mechanism how Plasmodium manages to evade this pre-invasive immune barrier is not well known. We investigated the influence of tripartite gut-microbiome-parasite interaction on human malaria parasite Plasmodium vivax in its natural/native vector Anopheles stephensi. Surprisingly we found that infectious blood meal lead to dramatic suppression in gut-bacteria population, a plausible strategy of P. vivax ookinetes to avoid immune responses. Our study suggests that for its own survival Plasmodium vivax causes early suppression of bacterial population, possibly by scavenging Fe from the blood meal which is indispensable for bacterial growth. Disruption and manipulation of this gut-microbe-interaction may help to design new paratransgenesis molecular tool for malaria control.

genomics↗