Biology subjects

Kaushik, M.

Publications and source records attributed to Kaushik, M..

3 recordsLinked to original sources

bioRxiv2021

Disentangling the effects of past logging and ongoing cryptic anthropogenic disturbance on vegetation structure and composition in Himalayan Foothills, India

Most tropical forests have undergone commercial logging. Even where logging has ceased, subsistence harvest of forest resources often persists especially in South-East Asia. Understanding of impacts of frequent forest resources extraction in areas recovering from past selective logging would be essential for designing the appropriate management interventions. We studied the impacts of current chronic anthropogenic disturbances (hereafter CAD) and past selective logging on vegetation structure, diversity, and regeneration, and the invasion of a non-native shrub, Lantana camara, in three major forest types in the Himalayan foothills, India. We analyzed field data on intensity of CAD and vegetation variables, collected from 269 stratified random plots, using ordination and generalized linear (mixed) modeling approaches. Our results, based on 2758 adult trees of 54 species, showed that forest types differed in disturbance regimes depending on protection level and availability of fodder tree species. Intensity of CAD depended on proximity to settlements (for livestock related disturbances). Whereas selective logging, including firewood collection, was associated with land protection status. Selective logging reduced the extent of mature forest but facilitated regeneration, thereby promoting secondary forest features such as tree density and canopy cover. In contrast, the interaction between lopping and selective logging was negatively associated with regeneration. Past logging facilitated L. camara invasion in Dry and Hill forests but not in Moist forest. Finally, while selective logging marginally enhanced tree diversity, CAD reduced native shrub diversity. Our study demonstrates that selective logging followed by CAD arrest forest recovery, as evident from the suppression of mature forest elements, loss of shrub biomass, reduced regeneration rate, and facilitation of invasive species. To abate these impacts, alternative livelihood/subsistence options that sustain forests and local communities should be explored. Additionally, CAD management should be site-specific as local ecological contexts modify their impacts on forests.

ecology↗

bioRxiv2020

Habitat patch size and tree species richness shape the bird community in urban green spaces of rapidly urbanizing region of India.

Rapid urbanization and associated biodiversity loss is rampant globally but especially a cause of concern for developing countries. However, numerous studies investigating the role of urban green spaces have established their key role in conserving larger suites of species in urban area. Yet our knowledge is lopsided due to lag in research in developing countries. We examined how landscape and local scale features of urban green spaces influence bird species richness, density, fine-foraging guild richness and composition during breeding and non-breeding season. This is the first study of this nature in one the Himalayan states of India. We quantified landscape level variables in the 250m buffer around 18 urban green spaces. We sampled vegetation and bird community during breeding and non-breeding season through 52 intensive sampling point spread across 18 urban green spaces. Size of the urban green space at landscape level and tree richness at the local scale emerged as important predictor variables influencing bird species richness, density and richness of imperiled insectivorous guild across seasons. Urban green spaces within education institutions and offices experiencing much less management supported higher bird richness and density whereas city parks were the most species poor. Community composition was affected more strongly by built-up cover and barren area in the matrix and also by tree species richness within urban green spaces. City planners should focus on establishing larger city parks during design stage whereas biodiversity potential of the existing urban green spaces could be enhanced by selecting native tree and shrub species to increase overall habitat complexity.

ecology↗

bioRxiv2020

Discovery of tREP-18, a novel class of tRNA encoded peptide with potent leishmanicidal activity

In the post genomic era, tRNA-derived fragments have emerged as a new class of non-coding gene regulators, those play crucial roles both at the transcriptional and translational levels, in different cellular biogenesis. However, none of the studies has ever asked whether tRNAs can also be translated into peptides with any biological significance. Thus, we present a novel hypothesis which suggested that; design and synthesis of tRNA-derived peptides from prokaryotic genome can be exploited for developing unique chemotherapeutics against neglected tropical diseases, like Visceral leishmaniasis (VL) and its aggressive form known as post kalazar dermal leishmaniasis (PKDL). To achieve this aim, we have used a novel system biology-based strategy, which involved; i) mining of unique tRNAs from E. coli genome and their translation into peptide in silico, ii) designing of theoretical 3D models to evaluate their stability, iii) prediction of their biological activity by screening against anti-parasitic database to filter the lead peptide. Based on this strategy, a unique tRNA-derived peptide (tREP-18) was selected, chemically synthesized, and used in vitro for elucidating its therapeutic significance against L. donovani, a causative agent of VL and PKDL. Our findings demonstrated that, tREP-18 can impose high level toxicity to L. donovani promastigotes, by disrupting the ultrastructural cellular architect, destabilizing the mitochondrial membrane potential ({Delta}{Psi}m), thus leading to drastic reduction in cell viability and proliferation. It also imparted high level of toxicity to BS12 a clinical isolate of PKDL. Conceivably, we for the first time reports a novel tRNA-derived peptide "tREP18" with excellent anti-leishmanial property, which can be further utilized for developing it as antileishmanial drug. One Sentence SummaryHere we report a novel first-in-class tRNA encoded peptide and its super anti-leishmanial characteristics.

synthetic biology↗