Biology subjects

Shrotri, S.

Publications and source records attributed to Shrotri, S..

7 recordsLinked to original sources

bioRxiv2026

Comprehensive Transcriptomic Analysis of Atopic Dermatitis Patients Documents the Spectrum of Molecular Abnormalities and the Response to Treatment

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by immune dysregulation and barrier dysfunction. To define the molecular architecture of AD in greater detail, we integrated lesional (LES) and non-lesional (NLS) transcriptomic data from multiple datasets using gene expression data from normal skin and psoriasis (PSO) and nummular eczema (NME) cohorts as reference. Gene set variation analysis revealed that adult AD exhibits broad immune activation and consistent barrier impairment in both LES and NLS skin, whereas pediatric AD is dominated by IL-1-driven inflammation with minimal barrier alteration. Comparative analyses showed stronger Th2 and myeloid activity in AD, metabolic enrichment in PSO, and complement and NK cell activation in NME. Longitudinal profiling identified temporal variation in Th1, Th2 and IFN pathways in AD skin. An eczema immune and cellular score, ECZECIS, was developed to quantify transcriptomic abnormalities and correlated with clinical improvement following dupilumab therapy. Among all treatments analyzed, dupilumab produced the most extensive reduction of immune and cytokine pathway activity in skin and attenuated systemic immune activation in blood. These findings delineate distinct immune and barrier signatures across age groups and disease types and establish ECZECIS as a quantitative biomarker for monitoring molecular treatment response in AD.

bioinformatics↗

bioRxiv2024

Mass flowering and flowering asynchrony characterise a seasonal herbaceous community in the Western Ghats

Flowering synchrony within a community may be facilitated by climatic factors and by ecological interactions that promote shared pollination services. In contrast, flowering asynchrony is promoted when there is inter-species competition for pollinators. In this multiyear study, we analyse the flowering phenology of a seasonal, herbaceous community (Kaas plateau) in Western Ghats, India to identify environmental constraints that may influence flowering synchrony. We addressed the questions: (a) Is flowering seasonality correlated with climatic factors? (b) Is there evidence for flowering synchrony within the community? (c) Do plant-pollinator interactions shift with flowering phenology? In Kaas, we recorded flowering phenology of 76 herbaceous species and found that climatic factors influenced their flowering phenology. We also identified the community to be composed of a few mass flowering (MF) species ([~]30%) and several non-mass flowering (nMF) species ([~]70%). Using two novel synchrony indices, temporal overlap (SItemp) and synchrony in abundance (SIabd), we also identified higher asynchronous flowering within the community than expected. Notably, species sharing the same floral colour, showed marked absence of synchrony, thus suggesting that competition and not pollinator-mediated facilitation drives flowering asynchrony within Kaas. Finally, pollination networks were observed to shift with flowering abundances within the community. Our findings reveal that even seasonal landscapes like the laterite plateaus, despite their short flowering season that last only 4-5 months, exhibit an overall asynchronous flowering phenology. And, the synchronous flowering for which the Kaas plateau is famous, was noted to be mostly due to a few mass flowering species that alter across years.

ecology↗

bioRxiv2024

Revisiting Aristotle's observation on bees: High floral constancy is common among bees but it is shaped by the locally abundant flowering species

Floral constancy is the tendency of a pollinator to sequentially visit flowers of the same species despite the availability of other rewarding plants. In a phytodiverse community, resource assurance may lead to pollinators displaying floral constancy to the most abundant plant species. We tested this by investigating if pollinators are floral constant on the abundant or the non-abundant plants within a seasonally flowering tropical community. We quantified floral constancy in three social (Apis spp.) and two solitary (non-Apis) Indian native bees using three approaches, that is by manually tracking the bees, analysing their pollen load, and examining pollen sacs of returning bees at their hive. We next examined in Apis cerana indica if constancy in individual bees translated to hive-level constancy. We found that in our community with distinct co-flowering patches, bees were constant to the most abundant species within a localised patch, and not to the most abundant species in the landscape. While the pollen loads from both the social and solitary bees suggested that they show high floral constancy (> 70% uni-dominant pollen), their values differed significantly (p < 0.0001). Finally, approximately 90% of individuals within a hive showed floral constancy (monolectic), but collectively, a hive displayed polylectic foraging. Our findings highlight that the foraging patterns of native pollinators has been understudied and is a critical first step towards connecting reproductive assurances to plant-pollinator dependencies in large landscapes.

animal behavior and cognition↗

bioRxiv2024

Pollinator visitation pattern and differential reproductive compatibilities maintain bract colour polymorphism in a nocturnal ginger from Western Ghats, India

Background and aimsFloral color polymorphism is common in angiosperms, yet in perennial, clonal plants, proximate trait differences and reproductive differences among sympatric morphs remain poorly understood. This is primarily because perennial individuals can carry signatures of past selection regimes. We studied bract color polymorphism in a nocturnal ginger Curcuma caulina to ask: (i) Do nectar rewards, reproductive compatibility and pollinator visitation differ among color morphs? (ii) Does morph abundance correlate with fitness via ecological (pollinator-mediated) or physiological (compatibility) pathways? (iii) Do these traits predict realized reproductive success? MethodsWe measured 22 floral/vegetative traits (n=30 per morph), nectar rewards (106 flowers), pollinator visitation rates (648 hours), and physiological compatibility (471 hand-pollinations treatments) and natural fruit and seed set ([≥]50 per morph) across three dominant morphs. Path analysis tested direct and indirect effects of morph abundance, nectar traits, pollinator visitation, and compatibility on reproductive fitness. Key resultsMorphs did not differ in their morphological traits but showed differential nectar and reproductive compatibility traits. The rare red-white morph produced the highest nectar energy, received the most visits, had a leaky self-compatibility, and yet showed lowest seed count per fruit, while the most common green-red morph was self-incompatible, showed higher cross-compatibility and had highest seeds per fruit. The second common green-white morph showed intermediate abundance and also showed leaky self-compatibility. Path analysis indicated that morph abundance had both direct and indirect effects on reproductive fitness, mediated by nectar, pollinator visitation and compatibility. ConclusionsReproductive success of the polymorphic C. caulina is a result of multi-trait interactions including pollinator interaction. That is, nectar traits and mating-system differences shape reproductive fitness of the morphs. We also highlight that in polymorphic perennial plants contemporary selection regimes may be acting alongside genotypic vestiges (historical genotypes present in extant population), thus complicating any frequency-dependent selection regime.

ecology↗

bioRxiv2021

The genome trilogy of Anopheles stephensi, an urban malaria vector, reveals structure of a locus associated with adaptation to environmental heterogeneity

BackgroundAnopheles stephensi is the most menacing malaria vector to watch for in newly urbanizing parts of the world. The fitness is reported to be a direct consequence of the vector adapting to laying eggs in over-head water tanks with street-side water puddles polluted by oil and sewage. Large frequent inversions of malaria vectors are implicated in adaptation. ResultsWe report the assembly of a strain of An. stephensi of the type-form, collected from a construction site from Chennai (IndCh) in 2016. The genome completes the trilogy with respect to a 16 Mbp inversion (2Rb) in An. stephensi associated with adaptation to environmental heterogeneity. Comparative genome analysis revealed breakpoint structure and allowed extraction of 22,650 segregating SNPs for typing this inversion. Using whole genome sequencing of 82 individual mosquitoes, we conclude that one third of both wild and laboratory populations maintain heterozygous genotype of 2Rb. The large number of SNPs are tailored to assign inversion genotype directly from 1740 exonic SNPs 80% of which are expressed in various developmental stages. ConclusionsThe genome trilogy approach accelerates study of fine structure and typing of important inversions in malaria vectors putting the genome resources for the much understudied An. stephensi, on par with the extensively studied malaria vector, Anopheles gambiae. We argue that the IndCh genome is relevant for field translation work compared to those reported earlier by showing that individuals from diverse populations cluster with IndCh pointing to significant commerce between cities, perhaps, allowing for survival of the fittest strain.

genomics↗

bioRxiv2020

When to be a male? Role of resource-limitation and pollinators in determining gender in an andromonoecious spiderwort.

The evolution and maintenance of sexual systems in plants is often driven by resource allocation and pollinator preferences, and very little is known about their role in determining floral sex expression in plants. In annual, entomophilous plants three major constraints can be identified towards optimal reproduction: 1) nutrient resources available from the environment, 2) nutrient resources allocated towards reproduction, i.e., fruits vs. flowers, and 3) pollinator visitations.Andromonoecy is a sexual system where plants bear both staminate and hermaphrodite flowers on the same inflorescence. The optimal resource allocation hypothesis suggests that under nutrient constraints, plants will produce more male flowers since they are energetically cheaper to produce over the more expensive hermaphrodite flowers. We test this hypothesis in the andromonoecious Murdannia simplex (Commelinaceae) by quantifying male and hermaphrodite flowers in a natural population and contrasting the distribution of the two sexes in plants from two resource conditions (stream population vs. plateau population). We next carried out choice experiments to test pollinator preference towards a specific sex.We found that in M. simplex, production of hermaphrodite flowers is resource-dependent and under resource constraints fewer numbers of flowers were produced and most of them were males. We failed to observe pollinator preference towards either sex but Amegilla spp. and Apis cerana showed higher visitation towards the most abundant sex within a trial, suggesting frequency-dependent visitation. Thus, we conclude that environmentally driven resource constraints play a bigger role in driving floral sex expression in Murdannia over direct pollinator-driven constraints.Competing Interest StatementThe authors have declared no competing interest.View Full Text

ecology↗

bioRxiv2020

Comprehensive Transcriptomic Analysis of COVID-19 Blood, Lung, and Airway

AbstractSARS-CoV2 is a previously uncharacterized coronavirus and causative agent of the COVID-19 pandemic. The host response to SARS-CoV2 has not yet been fully delineated, hampering a precise approach to therapy. To address this, we carried out a comprehensive analysis of gene expression data from the blood, lung, and airway of COVID-19 patients. Our results indicate that COVID-19 pathogenesis is driven by populations of myeloid-lineage cells with highly inflammatory but distinct transcriptional signatures in each compartment. The relative absence of cytotoxic cells in the lung suggests a model in which delayed clearance of the virus may permit exaggerated myeloid cell activation that contributes to disease pathogenesis by the production of inflammatory mediators. The gene expression profiles also identify potential therapeutic targets that could be modified with available drugs. The data suggest that transcriptomic profiling can provide an understanding of the pathogenesis of COVID-19 in individual patients. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=168 HEIGHT=200 SRC="FIGDIR/small/121889v1_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@7dccedorg.highwire.dtl.DTLVardef@1190e1forg.highwire.dtl.DTLVardef@1ee2e67org.highwire.dtl.DTLVardef@289f72_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗