Biology subjects

Amin, M. S.

Publications and source records attributed to Amin, M. S..

3 recordsLinked to original sources

bioRxiv2025

Distribution and environmental drivers of multi-functional community traits in the Sundarbans mangrove forest

Mangrove forests are vital blue-carbon ecosystems, playing a crucial role in global carbon storage, climate regulation, and biodiversity conservation. However, escalating environmental threats, particularly salinity intrusion, necessitate a deeper understanding of their functional dynamics to inform effective conservation and restoration strategies. This study examines the distribution of multi-functional community traits (MFCT) and their environmental drivers across mangrove functional groups (pioneer, mid-successional, climax) along salinity gradients in the Sundarbans, the worlds largest mangrove forest. Using data from 62 plots, nine functional traits from 17 mangrove species were analysed to evaluate MFCT diversity and its environmental determinants. Results revealed distinct variations in MFCT diversity, with mid-successional species exhibiting the highest trait diversity (64.0 {+/-} 1.58), followed by climax (51.3 {+/-} 2.09) and pioneer groups (50.2 {+/-} 2.26). Climax species demonstrated resilience to salinity increases (R{superscript 2} = 0.29, p < 0.001), whereas mid-successional and pioneer groups were negatively affected (R{superscript 2} = 0.22, p < 0.001 and R{superscript 2} = 0.17, p < 0.001). Annual precipitation exerted contrasting effects, reducing diversity in climax species (R{superscript 2} = 0.25, p < 0.001) but enhancing it in mid-successional (R{superscript 2} = 0.22, p < 0.001) and pioneer groups (R{superscript 2} = 0.06, p = 0.05). Notably, MFCT values remained stable across salinity gradients, underscoring the ecosystems functional resilience. These findings highlight mid-successional species as keystones in sustaining mangrove multifunctionality and resilience under environmental stressors. Prioritizing these species in conservation and restoration efforts can mitigate the impacts of salinity intrusion and climate variability. By integrating the MFCT framework, resource managers can develop targeted restoration strategies to enhance ecosystem functionality and long-term stability. These insights provide a critical foundation for policymakers to align global mangrove conservation with adaptive management strategies, reinforcing coastal resilience, biodiversity conservation, and climate change mitigation.

ecology↗

bioRxiv2023

Intranasal VLP-RBD vaccine adjuvanted with BECC470 confers immunity against Delta SARS-CoV-2 challenge in K18-hACE2-mice

As the COVID-19 pandemic transitions to endemic, seasonal boosters are a plausible reality across the globe. We hypothesize that intranasal vaccines can provide better protection against asymptomatic infections and more transmissible variants of SARS-CoV-2. To formulate a protective intranasal vaccine, we utilized a VLP-based platform. Hepatitis B surface antigen- based virus like particles (VLP) linked with receptor binding domain (RBD) antigen were paired with the TLR4-based agonist adjuvant, BECC 470. K18-hACE2 mice were primed and boosted at four-week intervals with either VLP-RBD-BECC or mRNA-1273. Both VLP-RBD-BECC and mRNA-1273 vaccination resulted in production of RBD-specific IgA antibodies in serum. RBD- specific IgA was also detected in the nasal wash and lung supernatants and were highest in VLP-RBD-BECC vaccinated mice. Interestingly, VLP-RBD-BECC vaccinated mice showed slightly lower levels of pre-challenge IgG responses, decreased RBD-ACE2 binding inhibition, and lower neutralizing activity in vitro than mRNA-1273 vaccinated mice. Both VLP-RBD-BECC and mRNA-1273 vaccinated mice were protected against challenge with a lethal dose of Delta variant SARS-CoV-2. Both vaccines limited viral replication and viral RNA burden in the lungs of mice. CXCL10 is a biomarker of severe SARS-CoV-2 infection and we observed both vaccines limited expression of serum and lung CXCL10. Strikingly, VLP-RBD-BECC when administered intranasally, limited lung inflammation at early timepoints that mRNA-1273 vaccination did not. VLP-RBD-BECC immunization elicited antibodies that do recognize SARS-CoV-2 Omicron variant. However, VLP-RBD-BECC immunized mice were protected from Omicron challenge with low viral burden. Conversely, mRNA-1273 immunized mice had low to no detectable virus in the lungs at day 2. Together, these data suggest that VLP-based vaccines paired with BECC adjuvant can be used to induce protective mucosal and systemic responses against SARS- CoV-2.

immunology↗

bioRxiv2022

SARS-CoV-2 Delta variant induces enhanced pathology and inflammatory responses in K18-hACE2 mice

The COVID-19 pandemic has been fueled by novel variants of concern (VOC) that have increased transmissibility, receptor binding affinity, and other properties that enhance disease. The goal of this study is to characterize unique pathogenesis of the Delta VOC strain in the K18-hACE2-mouse challenge model. Challenge studies suggested that the lethal dose of Delta was higher than Alpha or Beta strains. To characterize the differences in the Delta strains pathogenesis, a time-course experiment was performed to evaluate the overall host response to Alpha or Delta variant challenge. qRT-PCR analysis of Alpha- or Delta- challenged mice revealed no significant difference between viral RNA burden in the lung, nasal wash or brain. However, histopathological analysis revealed high lung tissue inflammation and cell infiltration following Delta- but not Alpha-challenge at day 6. Additionally, pro-inflammatory cytokines were highest at day 6 in Delta-challenged mice suggesting enhanced pneumonia. Total RNA-sequencing analysis of lungs comparing infected to uninfected mice revealed that Alpha-challenged mice have more total genes differentially activated, conversely, Delta-challenged mice have a higher magnitude of differential gene expression. Delta-challenged mice have increased interferon-dependent gene expression and IFN-{gamma} production compared to Alpha. Analysis of TCR clonotypes suggested that Delta challenged mice have increased T-cell infiltration compared to Alpha challenged. Our data suggest that Delta has evolved to engage interferon responses in a manner that may enhance pathogenesis. The in vivo and in silico observations of this study underscore the need to conduct experiments with VOC strains to best model COVID-19 when evaluating therapeutics and vaccines. ImportanceThe Delta variant of SARS-CoV-2 is known to be more transmissible and cause severe disease in human hosts due to mutations in its genome that are divergent from previous variants of concern (VOC). Our study evaluates the pathogenesis of Delta in the K18-hACE2 mouse model compared to the Alpha VOC. We observed that relative to Alpha, Delta challenge results in enhanced inflammation and tissue damage with stronger antiviral responses. These observations provide insight into Deltas unique pathogenesis.

immunology↗