Biology subjects

Mondal, T.

Publications and source records attributed to Mondal, T..

13 recordsLinked to original sources

bioRxiv2026

Stepwise Proteinase K Digestion Improves Genomic DNA Yield and Purity from Goat Semen: A Comparative Pilot Study of Five Extraction Protocols

Background: Genomic DNA of high quality is a prerequisite for molecular genetic analyses. However, DNA extraction from goat semen is frequently challenged by highly compacted sperm chromatin and the presence of enzymatic inhibitors within the seminal plasma. Objectives: This pilot study aimed to identify a reliable and cost-effective method for isolating high-quality genomic DNA from caprine semen. Methods: Five extraction protocols were evaluated: an unmodified blood protocol (Protocol B), two modifications of a sperm protocol (Modified Protocols 1 and 2), and a stool protocol (Protocol BS) using a commercial spin-column kit (Kit A), alongside a second commercial silica membrane kit (Kit B). Three technical replicates per protocol were processed from a single frozen semen straw of a Black Bengal buck (with one replicate evaluated for Protocol B). Extracted DNA was evaluated based on concentration, purity (absorbance ratios A260/A280 and A260/A230), cost per sample, and PCR amplification success of the mitochondrial hypervariable region 1 (HVR1). Results: Modified Protocol 2 utilizing 100 uL of semen and two sequential 1.5-hour proteinase K incubations at 55 degrees C yielded the highest normalized DNA concentration (mean +/- SD: 55.9 +/- 30.4 ng/uL semen), optimal purity ratios (A260/A280 = 1.78; A260/A230 = 2.06), and the lowest cost per nanogram of DNA (INR 0.073 +/- 0.037). All extracts from this protocol were successfully amplified via PCR. While the Kruskal-Wallis test for normalized yield did not reach statistical significance (p = 0.075), rendering yield differences exploratory, Modified Protocol 2 demonstrated the strongest overall performance. Conclusions: Modified Protocol 2 offers a promising, cost-efficient workflow for caprine sperm DNA isolation. Given that this pilot study sampled a single animal, these findings must be validated using biological replicates from multiple bucks prior to widespread implementation.

molecular biology↗

bioRxiv2025

Telomeric Repeat-Containing lncRNA TERRA Targets Non-Telomeric DNA in Trans via R-Loops

Telomeres are transcribed into telomeric repeat-containing RNA (TERRA), a long non-coding RNA known to play key roles in telomere maintenance and DNA repair. While TERRAs formation of R-loops at telomeric regions is well documented, its interaction with non-telomeric DNA remains poorly understood. In this study, we reanalyzed publicly available datasets using bioinformatic approaches and found evidence that TERRA binds non-telomeric DNA regions in trans through R-loop formation. Notably, the presence of tandem telomeric repeat motifs within non-telomeric regions enhanced TERRA binding, suggesting sequence-dependent R-loop formation. Furthermore, analysis of previously identified TERRA-regulated genes revealed that such distal TERRA-DNA interactions may influence telomere elongation by modulating the expression of telomere maintenance factors. These findings provide new insights into the broader regulatory functions of TERRA beyond telomeres and suggest a potential mechanism for its role in genome-wide gene regulation via R-loops.

bioinformatics↗

bioRxiv2025

Stealth replication of SARS-CoV-2 Omicron in the nasal epithelium at physiological temperature

The COVID-19 pandemic was marked by successive waves of SARS-CoV-2 variants with distinct properties. The Omicron variant that emerged in late 2021 showed a major antigenic shift and rapidly spread worldwide. Since then, Omicron-derived variants have maintained their global dominance, for reasons that remain incompletely understood. We report that the original Omicron variant BA.1 evolved several traits that converged in facilitating viral spread. First, Omicron displayed an early replicative advantage over previous variants when grown in a reconstructed nasal epithelium model based on primary human cells. The increase in Omicron replication was more marked at the 33{degrees}C temperature characteristic of human nasal passages, resulting in a physiologically relevant advantage. Omicron also caused a decrease in epithelial integrity, as measured by transepithelial electrical resistance and caspase-3 activation. Furthermore, Omicron caused a more marked loss of motile cilia at 33{degrees}C than other variants, suggesting a capacity to impair mucociliary clearance. RNAseq analysis showed that Omicron induced a broad transcriptional downregulation of ciliary genes but only a limited upregulation of host innate defense genes at 33{degrees}C. The lower production of type I and type III interferons in epithelia infected by Omicron compared to those infected by the Delta variant, at 33{degrees}C as well as 37{degrees}C, confirmed the increased capacity of Omicron to evade the innate antiviral response. Thus, Omicron combined replication speed, motile cilia impairment, and limited induction of innate antiviral responses when propagated in reconstructed nasal epithelia at physiological temperature. Omicron has the capacity to propagate efficiently but stealthily in the upper respiratory tract, which likely contributed to the evolutionary success of this SARS-CoV-2 variant. AUTHOR SUMMARYThe COVID-19 pandemic was initially characterized by a rapid succession of viral variants that emerged independently of each other, with each of these variants outcompeting previous ones and rising to regional or global dominance. A major evolutionary shift occurred in late 2021, with the emergence of the highly divergent Omicron BA.1 variant. Since then, all the dominant SARS-CoV-2 variants have been derived from Omicron, for reasons that remain incompletely understood. In this study, we chose to compare the replication of SARS-CoV-2 variants in a human nasal epithelium model grown at 37{degrees}C but also at 33{degrees}C, a more physiological temperature that approximates that found in the nasal cavity. In this model, Omicron showed an early replicative advantage that was more marked at nasal physiological temperature. Omicron also markedly impaired the layer of motile cilia that normally contributes to the clearance of inhaled particles from the nasal mucosa. Even though it caused tissue damage, Omicron triggered only a minimal antiviral interferon response from epithelia grown at 33{degrees}C. Thus, Omicron has the capacity to propagate rapidly but stealthily in the nasal epithelium at physiological temperature, which helps account for the efficient dissemination of this variant worldwide.

microbiology↗

bioRxiv2024

Designing a Novel 3D Scaffold for Multiepitope Vaccine Development: Engineering Ag85a Protein for Enhanced Stability and Antigenicity

Designing multi epitope vaccine (MEV) by reverse vaccinology has become immensely important in the area of vaccine research due to the emergence of new pathogens as well as rise of multi drug resistant old evils like tuberculosis. Administering a vaccine may have the best possibility to save mankind from these unforeseeable events. The strategy of designing a MEV in-silico lies in a few basic steps, including procuring the amino acid sequence of the B cell and T cell epitopes from literature search, bioinformatics approach to construct a potent immunogen capable of eliciting both humoral and cell mediated response. But the challenge lies in the construction of a stable protein with a compact tertiary structure. Merely joining the epitopes one after another, may not be sufficient to achieve this. In this study, a methodology has been detailed to tackle this great challenge using a simple approach of protein engineering. A scaffold based MEV has been designed for the very first time against Mtb by converting a vaccine candidate protein, Ag85A into a scaffold by truncating its non-immunogenic regions so the gaps could be filled by the highly immunogenic epitopes. The stability of the MEV was estimated by molecular dynamics simulation.

biochemistry↗

bioRxiv2023

METTL3/MYCN cooperation drives m6A modification during trunk neural crest differentiation and represents a therapeutic vulnerability in MYCN-amplified neuroblastoma

Neuroblastoma (NB) is the most common extracranial childhood cancer, caused by the improper differentiation of developing trunk neural crest cells (tNCC) in the sympathetic nervous system. The N6-methyladenosine (m6A) epitranscriptomic modification controls post-transcriptional gene expression but the mechanism by which the m6A methyltransferase complex METTL3/METTL14/WTAP is recruited to specific loci remains to be fully characterized. We explored whether the m6A epitranscriptome could fine-tune gene regulation in migrating/differentiating tNCC. We demonstrate that the m6A modification regulates the expression of HOX genes in tNCC, thereby contributing to their timely differentiation into sympathetic neurons. Furthermore, we show that posterior HOX genes are m6A modified in MYCN-amplified NB with reduced expression. In addition, we provide evidence that sustained overexpression of the MYCN oncogene in tNCC drives METTL3 recruitment to a specific subset of genes including posterior HOX genes creating an undifferentiated state. Moreover, METTL3 depletion/inhibition induces DNA damage and differentiation of MYCN overexpressing cells and increases vulnerability to chemotherapeutic drugs in MYCN-amplified patient-derived xenografts (PDX) cells, suggesting METTL3 inhibition could be a potential therapeutic approach for NB.

cancer biology↗

bioRxiv2022

m6A modification of TERRA RNA is required for telomere maintenance and is a therapeutic target for ALT positive Neuroblastoma

Telomerase-negative tumors maintain telomere length by alternative lengthening of telomeres (ALT), but the underlying mechanism behind ALT remains poorly understood. A proportion of aggressive neuroblastoma (NB), particularly relapsed tumors, are positive for ALT (ALT+), suggesting that a better dissection of the ALT mechanism could lead to novel therapeutic opportunities. TERRA, a long non-coding RNA (lncRNA) derived from telomere ends, localizes to telomeres in a R-loop-dependent manner and plays a crucial role in telomere maintenance. Here we present evidence that RNA modification at the N6 position of internal adenosine (m6A) in TERRA by the methyltransferase METTL3 is essential for telomere maintenance in ALT+ cells, and the loss of TERRA m6A/METTL3 results in telomere damage. We observed that m6A modification is abundant in R-loop enriched TERRA, and the m6A-mediated recruitment of hnRNPA2B1 to TERRA is critical for R-loop formation. Our findings suggest that m6A drives telomere targeting of TERRA via R-loops, and this m6A-mediated R-loop formation could be a widespread mechanism employed by other chromatin-interacting lncRNAs. Furthermore, treatment of ALT+ NB cells with a METTL3 inhibitor resulted in compromised telomere targeting of TERRA and accumulation of DNA damage at telomeres, indicating that METTL3 inhibition may represent a therapeutic approach for ALT+ NB.

cancer biology↗

bioRxiv2022

Global loss of cellular m6A RNA methylation following infection with different SARS-CoV-2 variants

Host-viral interactions during SARS-CoV-2 infection are needed to understand COVID-19 pathogenesis and may help to guide the design of novel antiviral therapeutics. N6-methyladenosine modification (m6A), one of the most abundant cellular RNA modifications, regulates key processes in RNA metabolism during a stress response. Gene expression profiles observed post-infection with different SARS-CoV-2 variants show changes in the expression of genes related to RNA catabolism, including m6A readers and erasers. We found that infection with SARS-CoV-2 variants caused a loss of m6A in cellular RNAs, whereas m6A was detected abundantly in viral RNA. METTL3, the m6A methyltransferase, showed an unusual cytoplasmic localization post-infection. The B.1.351 variant had a less pronounced effect on METTL3 localization and loss of m6A than the B.1 and B.1.1.7 variants. We also observed a loss of m6A upon SARS-CoV-2 infection in air/liquid interface cultures of human airway epithelia, confirming that m6A loss is characteristic of SARS-CoV-2 infected cells. Further, transcripts with m6A modification were preferentially down-regulated post-infection. Inhibition of the export protein XPO1 resulted in the restoration of METTL3 localization, recovery of m6A on cellular RNA, and increased mRNA expression. Stress granule formation, which was compromised by SARS-CoV-2 infection, was restored by XPO1 inhibition and accompanied by a reduced viral infection in vitro. Together, our study elucidates how SARS-CoV-2 inhibits the stress response and perturbs cellular gene expression in an m6A-dependent manner.

molecular biology↗

bioRxiv2022

Cinemeducation improves early clinical exposure to Inborn Errors of Metabolism

BackgroundCinemeducation has been shown to be an effective tool to help the students develop humanistic skills. However, there is a dearth of studies to find out if this can also be utilized to improve the interest and satisfaction of students learning about rare diseases such as the Inborn Errors of Metabolism. The aim was to introduce cinemeducation as part of early clinical exposure in teaching the inborn errors of metabolism for first-year MBBS students in the Department of Biochemistry. The Objectives were 1) to develop, validate and assess the feasibility of structured modules on Cinemeducation in teaching the Inborn Errors of Metabolism, 2) to study the impact of Cinemeducation on the satisfaction, interest, and academic performance of first-year MBBS students and 3) to study the perception of students and faculty towards Cinemeducation MethodsThis was a quasi-experimental, cross-over study involving 100 MBBS students in the Department of Biochemistry, AIIMS Kalyani. Movie clips prepared from Lorenzos Oil (for Lipid metabolism) and Extraordinary Measures (for Lysosomal Storage Disease) and corresponding paper-based cases; questionnaires and feedback forms were validated by expert group review. Analysis of quantitative data was performed in GraphPad, MS Excel and MAXQDA2022 software. Findings, Discussions and ConclusionsStudents academic performance was found to be improved in the groups where the Extraordinary Measures movie was used for Cinemeducation. Both learners and facilitators were satisfied with Cinemeducation. Cinemeducation was effectively introduced for teaching Inborn Errors of Metabolism in the Department of Biochemistry.

scientific communication and education↗

bioRxiv2022

Decoding the Effects of Spike Receptor Binding Domain Mutations on Antibody Escape Abilities of Omicron Variants

Recent times witnessed an upsurge in the number of COVID cases which is primarily attributed to the emergence of several omicron variants, although there is substantial population vaccination coverage across the globe. Currently, many therapeutic antibodies have been approved for emergency usage. The present study critically evaluates the effect of mutations observed in several omicron variants on the binding affinities of different classes of RBD-specific antibodies using a combined approach of immunoinformatics and binding free energy calculations. Our binding affinity data clearly show that omicron variants achieve antibody escape abilities by incorporating mutations at the immunogenic hotspot residues for each specific class of antibody. K417N and Y505H point mutations are primarily accountable for the loss of class I antibody binding affinities. The K417N/Q493R/Q498R/Y505H combined mutant significantly reduces binding affinities for all the class I antibodies. E484A single mutation, on the other hand, drastically reduces binding affinities for most of the class II antibodies. E484A and E484A/Q493R double mutations cause a 33-38% reduction in binding affinity for the approved therapeutic monoclonal antibodies, Bamlanivimab (LY-CoV555). The Q498R RBD mutation observed across all the omicron variants can reduce ~12% binding affinity for REGN10987, a class III therapeutic antibody, and the L452R/Q498R double mutation causes a ~6% decrease in binding affinities for another class III therapeutic antibody, LY-CoV1404. Our data suggest that achieving the immune evasion abilities appears to be the selection pressure behind the emergence of omicron variants.

bioinformatics↗

bioRxiv2021

Distribution modeling of Lantana camara and identification of hotspot for future management of the species in the lower Shivalik region of Uttarakhand, India

Invasive alien species are one of the most significant threats to biodiversity of the earth ecosystem. Spatial modeling has played a vital role in predicting and mapping the suitable areas of the species habitat for management implementation. Lantana camara is one of the ten worst invasive weed enlisted by IUCN., and has its distribution in more than 154000 sq. km area in India. We predicted the distribution of Lantana camara using Ecological Niche Modeling (ENM) in MaxEnt software for Rajaji- Corbett landscape in the lower Shivalik region of the state of Uttarakhand, India. The predicted area for the invasion was classified into four categories high, good, medium, and low potential areas. The distribution hotspots were identified using Getis Ord G* method in ArcGIS 10.5 by calculating plot-wise species occurrence. Major hotspot areas under threat of high infestation are Dholkhand, Gohri, Ramgarh, Motichur, and Chilla from Rajaji Tiger Reserve, Palain, Mandal and Maidavan from Kalagarh Tiger Reserve and Bijrani, Dheela, Dhikala, Jhirna and Kalagarh from Corbett Tiger Reserve. This study provides a current status of the invasive species in the landscape with identified areas that need immediate actions to control the spread of the species. The study results can help the policymakers and stakeholders build an efficient and strategically weed management plan.

ecology↗

bioRxiv2020

Insight into the autosomal-dominant inheritance pattern of SOD1-associated ALS from native mass spectrometry

About 20% of all familial amyotrophic lateral sclerosis (ALS) cases are associated with mutations in superoxide dismutase (SOD1), a homodimeric protein. The disease has an autosomal-dominant inheritance pattern. It is, therefore, important to determine whether wild-type and mutant SOD1 subunits self-associate randomly or preferentially. A measure for the extent of bias in subunit association is the coupling constant determined in a double-mutant cycle type analysis. Here, cell lysates containing co-expressed wild-type and mutant SOD1 subunits were analyzed by native mass spectrometry to determine these coupling constants. Strikingly, we find a linear positive correlation between the coupling constant and the duration of the disease. Our results indicate that inter-subunit communication and a preference for heterodimerization greatly increase the disease severity.

biochemistry↗

bioRxiv2019

An assessment of land use land cover change in Central Highland of Deccan Peninsula and Semi-Arid tracts of India

Human consumption and management of land, i.e., how people transmit to a landscape as a source of livelihood, shelter, recreation, or industry, are powerful forces shaping patterns and dynamics in human-occupied landscapes. Understanding and managing landscape change, therefore, requires a thorough knowledge of the developmental processes the area is undergoing, causing the change in the land use pattern over time. In this study land use/cover dynamics of the Central Highland of Deccan Peninsula and Semi-Arid zone of Gujarat Rajputana bio-geographic regions of India was assessed using a combination of hybrid classification, markov analysis approach within the time frame of 2000-2013. In this time frame, major changes have been identified in dense forest, open forest, cropland, fallow land and in the barren landforms. The landscape has witnessed a substantial increase in built-up areas from 31317 sq. km. in 2000 to 52338 sq. km in 2013. The scrubland has largely declined from 35713.06 sq. km in 2000 to 23003.88 sq.km in 2013; it might have resulted from the transition of scrubland to the fallow land which was predicted as more than 70% in the first phase and more than 30% in the later phase. The area under dense forest constantly decreased in the studied time (84027 sq. km to 71225.37 sq. km). The Markov analysis estimated a probability of changing of open forest types to fallow land (36% in 2000-2006 and 20% in 2006-2013). As the environmental damage is irreversible due to industrialization, therefore a sound strategy needs to be implemented for sustainable use of natural resources that can go hand in hand.

ecology↗

bioRxiv2018

Rat bone marrow derived mesenchymal stem cells differentiate to germ cell like cells

Summary StatementThe in vitro differentiation of rMSCs provides an excellent model for studying cell commitment and their potential in stem cell technology. We have demonstrated that rat bone marrow derived MSCs are able to differentiate into germ-line cells in vitro which has an enormous scope in the advancement of fertility research. In future, this technique can be utilized in different domestic animal species for propagation of elite germ plasm.\n\nAbstractGerm cells undergo distinctive male or female pathways to produce spermatozoa or oocyte respectively essential for sexual reproduction. Mesenchymal stem cells (MSCs) have the capacity of trans-differentiation to form the multiple lineages of cells of mesoderm, endoderm, and ectoderm origin. Herein, MSCs were isolated from rat bone marrow and characterized by their morphological features, expression of surface markers by immunophenotyping and molecular biology tools as well as self renewal and differentiation capability. Thereafter, by inducing these cells with retinoic acid we could able to show that bone marrow derived MSCs are able to trans-differentiate into male germ cell-like cells which were further characterized by the expressions of germ cell specific markers. This in vitro study for the generation of germ-like cells suggests that bone marrow MSCs can be a potential source of germ cells that could be a sustainable source of sperm / oocyte production for potential therapeutic applications in future. Moreover, this technique can be applied in different domestic animal species for propagation of elite germ plasm.

cell biology↗