Biology subjects

Rahman, M. F.

Publications and source records attributed to Rahman, M. F..

6 recordsLinked to original sources

bioRxiv2026

Crown-based growth strategies explain the distribution and co-occurrence of tree functional groups along environmental gradients

Elucidating interspecific variation in growth strategies across environments is critical for understanding tree diversity and distribution. However, a systematic analysis across diverse forests remains scarce due to limited large-tree crown measurements. We analysed 3,814 trees from 107 canopy species in 23 natural forests using forest census data and unmanned aerial vehicle. Relative growth rate (growth rate/biomass) was decomposed into growing space efficiency (growth rate/crown area) and crown area ratio (crown area/biomass). Relative growth rates were similar among functional groups (deciduous broadleaf, evergreen broadleaf, evergreen conifer), but their underlying components differed. Deciduous trees exhibited 34-43% higher crown area ratio but 24-27% lower growing space efficiency than evergreen broadleaf and conifer trees. Across environments, growing space efficiency correlated positively with mean annual temperature, likely from extended growing seasons while crown area ratio correlated negatively, particularly in deciduous species. Snow loading limited crown area ratio in evergreen species, while deciduous achieved higher values through avoiding snow loads. Correlation between crown area ratio and specific leaf area indicated a coordinated strategy between crowns and leaves. Different functional groups achieve comparable growth efficiency either through crown expansion or biomass production, explaining their distinct distribution as well as co-occurrence across broad environments.

ecology↗

bioRxiv2024

Immune disease dialogue of chemokine-based cell communications as revealed by single-cell RNA sequencing meta-analysis

Immune-mediated diseases are characterized by aberrant immune responses, posing significant challenges to global health. In both inflammatory and autoimmune diseases, dysregulated immune reactions mediated by tissue-residing immune and non-immune cells precipitate chronic inflammation and tissue damage that is amplified by peripheral immune cell extravasation into the tissue. Chemokine receptors are pivotal in orchestrating immune cell migration, yet deciphering the signaling code across cell types, diseases and tissues remains an open challenge. To delineate disease-specific cell-cell communications involved in immune cell migration, we conducted a meta-analysis of publicly available single-cell RNA sequencing (scRNA-seq) data across diverse immune diseases and tissues. Our comprehensive analysis spanned multiple immune disorders affecting major organs: atopic dermatitis and psoriasis (skin), chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis (lung), ulcerative colitis (colon), IgA nephropathy and lupus nephritis (kidney). By interrogating ligand-receptor (L-R) interactions, alterations in cell proportions, and differential gene expression, we unveiled intricate disease- specific and common immune cell chemoattraction and extravasation patterns. Our findings delineate disease-specific L-R networks and shed light on shared immune responses across tissues and diseases. Insights gleaned from this analysis hold promise for the development of targeted therapeutics aimed at modulating immune cell migration to mitigate inflammation and tissue damage. This nuanced understanding of immune cell dynamics at the single-cell resolution opens avenues for precision medicine in immune disease management.

immunology↗

bioRxiv2024

An immunocompetent human kidney on-a-chip model to study renal inflammation and immune-mediated injury

Kidney damage and dysfunction is an emerging health issue worldwide resulting in high morbidity and mortality rates. Numerous renal diseases are recognized to be driven by the immune system. Despite this recognition, the development of targeted therapies has been challenging as knowledge of the underlying mechanism and complex interactions remains insufficient. Recent advancements in the field offer promising avenues for exploring the interplay between renal cells and immune cells and their role in the development of renal inflammation and diseases. This study describes the establishment of a human immunocompetent 3D in vitro co-culture model of the proximal tubule in a high-throughput microfluidic platform that can be used to study renal functionality and inflammatory processes. The model incorporated RPTEC in the top compartment and HUVECs in the bottom compartment cultured under flow and in direct contact with a collagen-I ECM gel resulting in the formation of polarized tubular structures. As an immune component, human primary monocytes of different donors were added to the lumen of the endothelium. Renal inflammation was successfully induced using complement activated serum (CAS) as evident by epithelial morphological changes, increased expression of adhesion molecules, release of pro-inflammatory cytokines, and reduced epithelial viability. Realtime migratory behavior of monocytes showed increased extravasation and migration towards the ECM and Renal compartment upon exposure to CAS with donor-to-donor differences observed. Finally, immune modulatory compounds showed efficacious inhibition of monocyte migration under inflammatory conditions in the microfluidic co-culture model. A successful co-culture model was established and can be applied to study renal functionality in health and disease but also for drug screening due to the compatibility of the platform with automation and relatively high throughput. Overall, the described proximal tubule model has high potential to fill the gap that currently exists to study renal inflammation preclinically.

immunology↗

bioRxiv2022

Bacterial communities associated with the surfaces of the fresh fruits sold around Dhaka Medical College and Hospital and their anti-microbial profiles

BackgroundNow-a-days, fresh fruits are popular sources of healthy diets with low energy density. Since they are consumed raw, it may act as a source of foodborne disease and a reservoir for antibiotic resistant organisms. This study aimed to determine microbial prevalence among the fruits sold outside Dhaka Medical College Hospital (DMCH) along with their antimicrobial profiles and to detect antimicrobial resistance genes among the resistant organisms. MethodsThirty-five different types of fruits were bought from around DMCH and analyzed for the presence of bacteria. Antibiotic sensitivity was done and ESBL, AmpC {beta}-lactamase, and MBL positive strains were identified by standard methods followed by PCR to detect ESBL, AmpC {beta}-lactamase, and MBL genes. FindingsTwenty seven different organisms were isolated and identified which were-Klebsiella spp (33{middle dot}33%), Citrobacter spp (29{middle dot}64%), Enterobacter spp (22{middle dot}22%), Escherichia coli (11{middle dot}11%), and Staphylococcus aureus (3{middle dot}70%). Among them 48{middle dot}15% organisms were resistant to different antibiotics. Only one organism (Citrobacter spp) produced ESBL phenotypically (7{middle dot}69%). Two (15{middle dot}38%) were positive for AmpC {beta}-lactamase and one of these (Enterobacter spp) possessed both SHV and CTX-M15A genes by PCR. Imipenem resistance was 84{middle dot}62% of the antibiotic resistant organisms, and 10 (90{middle dot}91%) were phenotypically MBL positive by CD test, DDS test, and MHT. By PCR, one Enterobacter spp had MBL encoding gene OXA-48. InterpretationFresh fruits, contaminated with pathogens, might be a source of transmission of resistant organisms and attribute to public health issues. FundingThe office of Directorate General of Health Service, Ministry of Health and Family Welfare, Bangladesh. ImportanceFruits sold around Dhaka Medical College and Hospital (DMCH) are usually consumed by patients, patients attendant and Health care worker. This investigation emphasized not only on the extent of bacterial contamination but also attempted to measure the anti-microbial profile of these organisms isolated from the fruits commonly available and readily consumed in and around DMCH.

microbiology↗

bioRxiv2019

Maternal high-fat diet induces sex-specific effects on inflammatory responses to corticosterone and lipopolysaccharide challenge in adult rat offspring

BackgroundAcute elevations in endogenous corticosterone (CORT) with psychosocial stress or exogenous administration potentiate inflammatory gene expression. Maternal obesity as a result of high-fat diet (HFD) consumption has been linked to higher basal levels of neuroinflammation, including increased expression of pro-inflammatory genes in the amygdala. These findings suggest that exposure to maternal HFD may elicit pro-inflammatory responses in the presence of an immune stressor such as lipopolysaccharide (LPS), a component of gram-negative bacteria, as well as acute elevated CORT. MethodsRat offspring were exposed to maternal HFD or control diet (CHD) throughout pre and postnatal development until weaning, when all offspring were provided CHD until adulthood. In adulthood, offspring were challenged with administration of exogenous CORT, to simulate an acute physiological stress, LPS, to induce an immune stress, or both. qPCR was used to measure transcript abundance of CORT receptors and downstream inflammatory genes in the amygdala, hippocampus and prefrontal cortex, brain regions that mediate neuroendocrine and behavioral responses to stress. ResultsHFD female offspring exhibited elevations in anti-inflammatory transcripts, whereas HFD male offspring responded with greater pro-inflammatory gene expression to simultaneous CORT and LPS administration. ConclusionsThese findings suggest that exposure to maternal HFD leads to sex-specific alterations that may alter inflammatory responses in the brain, possibly as an adaptive response to basal inflammation.

neuroscience↗

bioRxiv2019

Studies on Biochemical Changes and Prolactin Level Evaluation in Patients with Chronic Kidney Disease

BackgroundChronic kidney disease (CKD) is progressive loss in kidney function over a period of months or years. CKD is an internationally recognized public health problem affecting 5-10% of the world population and day-by-day the number of cases are increasing at an alarming rate. In CKD, raised levels of prolactin in blood may cause vascular derangements which might lead to worse cardiovascular consequences in CKD patients.\n\nObjectivesTo assess serum creatinine, hemoglobin (Hb), urea, red blood cell (RBC), protein creatinine ratio (PCR) and prolactin in CKD patients.\n\nMaterial and MethodsThis study included 110 patients, 61 were males and 49 were females and their age range 1 to more than 60 years. The control group also consisted of same number of participants as the patients; who were free from signs and symptoms of kidney disease and prolactin hormone disorders.\n\nResultsThe study shows that all the biochemical parameters in CKD patients were found to be significantly high compared with control group (P<0.001). Serum prolactin concentrations in CKD patients were also increased significantly compared with control group (P[≤] 0.05). It was found that level of prolactin hormone secretion was higher in male CKD patients than male control.\n\nConclusionAlthough males are more prone to chronic kidney disease, but the percentage of females is not negligible. All the biochemical parameters and prolactin level changed significantly in the CKD patients. It is interesting that in case of CKD, males prolactin secretion becomes higher.

biochemistry↗