Biology subjects

Naeem, S.

Publications and source records attributed to Naeem, S..

4 recordsLinked to original sources

bioRxiv2024

Clinical and Molecular Characterization of Glioma Patients: miR-21 Expression as a Prognostic Biomarker in Tissue and Serum

BackgroundGlioma remains challenging due to high recurrence rates and resistance to treatment. Diagnosis and follow-up in resource-constrained regions often leads to significant patient attrition. Serum microRNA (miRNA) expression profiles, which have been shown to correlate with tissue expression profiles, are detectable in peripheral blood samples, providing a promising avenue for non-invasive and repeatable liquid biopsies. miR-21 shows promise in many populations; however, there is a dearth of data from our region. MethodologyWe collected 90 tumor tissues, 42 pre- and post-operative serum samples from glioma patients, and included 10 normal tissue adjacent to the tumor (NATs) along with serum samples from 8 healthy individuals and analyzed for miR-21 expression through RT-qPCR. Shapiro Wilk test was applied to calculate data distribution, ANOVA, Fishers exact, and Wilcox test, along with pairwise Students t-test, were applied to determine the differences in gene expression. The expression level of miR-21 was assessed for correlation with Kaplan-Meier survival curves and different molecular markers (IDH, Ki-67, ATRX and p53). The quantitative hazard ratio was determined using Cox regression analysis. ResultsmiR-21 expression in tissue increased with the mean log fold expression 0.101 (median fold = 2.35) in grade 2, 1.00 (median fold = 7.49) in grade 3 and 1.53 (median fold = 26.0) in grade 4 for glioma patients. The expression level showed significant difference between control tissue and grade 4 patients along with significant inter-comparison between grade 1 and grade 4, as well as grade 2 and grade 4.A significant elevated expression of miR-21 has been noticed in patients above 50 years of age. Similarly, in serum samples a significant decline in miR-21 expression was observed in post-operative samples as compared to pre-operative samples mean log fold in grade 2 is 1.30 (11.6-fold), grade 3 is 1.08 (15.3-fold) and grade 4 is 0.749 (13.2-fold). Furthermore, there was positive correlation of miR-21 expression with tumor volume. IDH-wildtype and high Ki-67 expression in gliomas showed significant upregulation of miR-21 compared to IDH-mutant and low Ki-67 respectively. Patients with low miR-21 expression had significantly longer overall survival (OS) than patients with high miR-21 expression. Quantitative hazard analysis indicates that patients in the high expression group have a 3.4 times higher risk of mortality (95% CI: 1.6-7.1), in comparison to patients in the low expression group with AUC of 0.742 (all p <0.05). ConclusionThis study demonstrates the potential of microRNA 21 as a serum biomarker for early, cost-effective diagnosis of glioma. Furthermore, it may inform the development of targeted treatment strategies for various glioma grades, particularly in our population.

molecular biology↗

bioRxiv2022

Biodiversity effects on seedling biomass growth are modulated by light environment across functional groups

O_LITree biodiversity has the potential to ensure consistency in the functioning of forest ecosystems, not just over space, but over long-timescales by maintaining composition through recruitment. However, for continued buffering in the face of global environmental change, the sensitivity of biodiversity-ecosystem functioning relationships to heterogeneous environments needs to be understood. C_LIO_LISeedling recruitment in carbon-rich tropical forests is a result of biotic and abiotic drivers but their combined outcomes at the community-level remain poorly understood. Although biodiversity in seedling communities can potentially increase their growth and biomass accumulation, abiotic drivers like light can alter this effect through divergent effects on constituent species and functional groups. In forests with high baseline heterogeneity in microclimates, these processes can enhance or constrain regeneration. C_LIO_LIWe tested the effects and interactions between species richness and canopy cover on the growth of seedling communities consisting of tropical broad-leaved evergreen and deciduous forest species using a fully crossed manipulated experiment in the Andaman Islands, India and compared these with field observations from a long-term forest plot in the same landscape. C_LIO_LIWe show that in the critical seedling establishment phase, species richness and light increase community biomass independently. Accounting for variation across species, individual species on average accumulated more biomass in communities with both higher light and higher diversity. C_LIO_LIWe also show that overyielding in species rich communities fits expectations from a model of complementarity with non-random overyielding than selection or spatial insurance effects. C_LIO_LISynthesis Taken together, our results show that the potential for biodiversity to increase ecosystem functioning in seedling communities is modulated by light. Further understanding on the interaction of biodiversity with multiple abiotic drivers and their effect on regeneration dynamics is crucial for predicting future ecosystem functioning. C_LI

ecology↗

bioRxiv2020

Diversity reduces extinction risk at global scales

Increases in biodiversity often lead to greater, and less variable, levels of ecosystem functioning. However, whether species are therefore less likely to go extinct in more diverse systems is unclear. We use comprehensive estimates of avian taxonomic, phylogenetic and functional diversity to characterize the global relationship between multiple dimensions of diversity and extinction risk in birds. We find that more diverse assemblages have lower mean IUCN threat status despite being composed of species with attributes that make them more vulnerable to extinction, such as large body size or small range size. Our analyses also reveal that this reduction of current threat status associated with greater diversity far outweighs the increased risk associated with the accumulation of extinction-prone species in more diverse assemblages. These results suggest that species conservation targets can best be achieved by maintaining high levels of overall biodiversity in natural ecosystems.

ecology↗

bioRxiv2019

Trophic complexity alters the diversity-multifunctionality relationship in experimental grassland mesocosms

Higher levels of diversity within trophic levels are necessary to sustain multiple ecosystem functions, but this diversity-multifunctionality relationship peaks at intermediate percent-function thresholds. The presence of multiple trophic levels, or trophic complexity, affects ecosystem multifunctionality but its effect on the diversity-multifunctionality relationship has not been experimentally tested. To test the sensitivity of the diversity-multifunctionality relationship to trophic complexity, we simultaneously manipulated plant diversity and trophic complexity in a multifactorial tall-grass prairie mesocosm experiment at Cedar Creek, Minnesota, USA. Trophic complexity altered the diversity-multifunctionality relationship, by lowering the height of the peak as well as by shifting to a negative effect at lower thresholds. These outcomes are consistent with decreases in both the "jack-of-all-trades" effect and complementarity among plant species. Our findings suggest that trophic complexity, which is experiencing widespread declines on a global scale, is important for sustaining ecosystem multifunctionality in the face of equally widespread declines in biodiversity.

ecology↗