Biology subjects

Dsouza, M.

Publications and source records attributed to Dsouza, M..

3 recordsLinked to original sources

bioRxiv2025

Right-Lateralized Maladaptive Topological Reorganization in Hyperthyroidism

Hyperthyroidism (HT) has been associated with cognitive impairments, but the structural connectomic and molecular mechanisms underlying these deficits remain poorly understood. In this study, we investigated large-scale brain network reorganization using structural connectivity derived from diffusion MRI in patients with 30 hyperthyroidism and 28 matched control participants. Subject level connectomes were analyzed to characterize network topology, with a specific focus on hub architecture, nodal alterations, and hemispheric reorganization. To probe molecular underpinnings, we integrated normative neurotransmitter receptor and transporter density maps with network metrics, assessing their correspondence to observed connectomic disruptions. Individuals with hyperthyroidism exhibited increased structural connectivity, particularly in mid- and long-range connections, alongside disrupted network topology. These changes were characterized by reduced modularity, increased characteristic path length and hub reorganization, most prominently in subcortical and right-hemisphere regions. Importantly, network alterations were functionally relevant, as metrics showed significant associations with clinical and cognitive variables, including FT4 levels, BMI, and perceptuomotor performance in the hyperthyroid group. Spatial neuromolecular correspondence analyses further revealed that DAT, 5-HT2A, and NET were closely aligned with topological changes. Moreover, neurotransmitter-weighted within-module degree z-scores moderately predicted TSH levels in HT. Our findings demonstrate that hyperthyroidism is associated with an increase in redundant, spatially extended white matter connections and a marked right-lateralized asymmetry in network organization. Furthermore, serotonergic (5-HT1a) and dopaminergic (DAT) systems consistently contributed to the modulation of intra-modular hubness, suggesting their role in maladaptive structural reorganization that may underlie perceptuomotor dysfunction in hyperthyroidism.

neuroscience↗

bioRxiv2022

Microbiome response in an urban river system is dominated by seasonality over wastewater treatment upgrades

Microorganisms such as coliform-forming bacteria are commonly used to assess freshwater quality for drinking and recreational use. However, such organisms do not exist in isolation; they exist within the context of dynamic, interactive microbial communities which vary through space and time. Elucidating spatiotemporal microbial dynamics is imperative for discriminating robust community changes from ephemeral ecological trends, and for improving our overall understanding of the relationship between microbial communities and ecosystem health. We conducted a seven-year (2013-2019) microbial time-series investigation in the Chicago Area Waterways (CAWS): an urban river system which, in 2016, experienced substantial upgrades to disinfection processes at two wastewater reclamation plants (WRPs) that discharge into the CAWS and improved stormwater capture, to improve river water quality and reduce flooding. Using culture-independent and culture-dependent approaches, we compared CAWS microbial ecology before and after the intervention. Examinations of time-resolved beta distances between WRP-adjacent sites showed that community similarity measures were often consistent with the spatial orientation of site locations to one another and to the WRP outfalls. Fecal coliform results suggested that upgrades reduced coliform-associated bacteria in the effluent and the downstream river community. However, examinations of whole community changes through time suggest that the upgrades did little to affect overall riverine community dynamics, which instead were overwhelmingly driven by yearly patterns consistent with seasonality. Such results emphasize the dynamic nature of microbiomes in open environmental systems such as the CAWS, but also suggest that the seasonal oscillations remain consistent even when perturbed. ImportanceThis study presents a systematic effort to combine 16S rRNA gene amplicon sequencing with traditional culture-based methods to evaluate the influence of treatment innovations and systems upgrades on the microbiome of the Chicago Area Waterway System, representing the longest and most comprehensive characterization of the microbiome of an urban waterway yet attempted. We found that the systems upgrades were successful in improving specific water quality measures immediately downstream of wastewater outflows. Additionally, we found that the implementation of the water quality improvement measures to the river system did not disrupt the overall dynamics of the downstream microbial community, which remained heavily influenced by seasonal trends.

microbiology↗

bioRxiv2018

Agricultural Pollution Risks Influence Microbial Ecology in Honghu Lake

BackgroundAgricultural activities, such as stock-farming, planting industry, and fish aquaculture, can influence the physicochemistry and biology of freshwater lakes. However, the extent to which these agricultural activities, especially those that result in eutrophication and antibiotic pollution, effect water and sediment-associated microbial ecology, remains unclear.\n\nMethodsWe performed a geospatial analysis of water and sediment associated microbial community structure, as well as physicochemical parameters and antibiotic pollution, across 18 sites in Honghu lake, which range from impacted to less-impacted by agricultural pollution. Furthermore, the co-occurrence network of water and sediment were built and compared accorded to the agricultural activities.\n\nResultsPhysicochemical properties including TN, TP, NO3--N, and NO2--N were correlated with microbial compositional differences in water samples. Likewise, in sediment samples, Sed-OM and Sed-TN correlated with microbial diversity. Oxytetracycline and tetracycline concentration described the majority of the variance in taxonomic and predicted functional diversity between impacted and less-impacted sites in water and sediment samples, respectively. Finally, the structure of microbial co-associations was influenced by the eutrophication and antibiotic pollution.\n\nConclusionThese analyses of the composition and structure of water and sediment microbial communities in anthropologically-impacted lakes are imperative for effective environmental pollution monitoring. Likewise, the exploration of the associations between environmental variables (e.g. physicochemical properties, and antibiotics) and community structure is important in the assessment of lake water quality and its ability to sustain agriculture. These results show agricultural practices can negatively influence not only the physicochemical properties, but also the biodiversity of microbial communities associated with the Honghu lake ecosystem. And these results provide compelling evidence that the microbial community can be used as a sentinel of eutrophication and antibiotics pollution risk associated with agricultural activity; and that proper monitoring of this environment is vital to maintain a sustainable environment in Honghu lake.

microbiology↗