Biology subjects

Hossain, M.

Publications and source records attributed to Hossain, M..

29 records · Page 2Linked to original sources

bioRxiv2022

Genomic diversity of Streptococcus uberis isolated from clinical mastitis of cattle in selected areas of Bangladesh

Streptococci are the major etiology in mastitis, a cause of huge economic losses in the dairy industries. Streptococcus (S.) agalactiae, S. dysagalactiae and S. uberis are mostly encountered in bovine mastitis; however, data on the diversity and characteristics of Streptococcus in clinical mastitis of cattle in Bangladesh is lacking. Thus, the present study was aimed to determine the diversity and antimicrobial resistance pattern of Streptococcus spp. isolated from clinical mastitis of cattle reared in Bangladesh. A total of 105 milk samples comprising eighty (80) from cattle with clinical mastitis (CCM) and twenty-five (25) from apparently healthy cattle (AHC) in four prominent dairy farms and one dairy community were purposively collected and examined in this study. Milk samples were enriched in Luria Bertani broth (LB) and Streptococcus spp. was isolated on Modified Edwards Medium and identified by 16S rRNA gene sequencing. Among eighty (80) clinical samples, eighteen (18) were positive for Streptococcus spp. while none of the milk from AHC revealed Streptococcus by cultural and molecular examination. Sequencing and phylogenetic analysis identified 55.6%, 33.3%, 5.6% and 5.6% of the Streptococcus isolates as S. uberis, S. agalactiae, S. hyovaginalis and S. urinalis, respectively. Antibiotic sensitivity testing with antimicrobials commonly used to treat clinical mastitis revealed 100%, 100%, and 30% of the S. agalactiae, S. hyovaginalis, and S. uberis as multidrug-resistant, respectively. Molecular characterization through whole genome sequencing of five (5) S. uberis isolates identified at least two novel ST types of S. uberis circulating in the study areas with one ST (4/5 isolates) clustered with the isolates from China, India and Thailand, and the other (1/5) with UK, Ireland and Australia. Pan-genome analysis and phylogeny of the core genome sequences also clustered the isolates into two sub-clusters, indicating the presence of at least two different subtypes of S. uberis in the study area. On virulence profiling, all the isolates of this study were found to harbor at least 35 virulence and putative virulence genes probably associated with intramammary infection (IMI) indicating all the S. uberis isolated in this study as potential pathogen. From the overall findings it was evident that Strepococcus occurring in bovine mastitis are diverse and S. uberis genome carries an array of putative virulence factors which need to be investigated genotypically and phenotypically to identify a specific trait or determinant governing the virulence and fitness of this bacterium. Moreover, Streptococcus isolated in this study carried multidrug resistance which needs careful consideration during the selection of a treatment regimen for mastitis.

microbiology↗

bioRxiv2022

A novel anti-cancer therapy with nuclear export inhibitor Selinexor in combination with oncolytic myxoma virus

Oncolytic viruses exploited for cancer therapy are developed to selectively infect, replicate, and kill cancer cells to stop tumor growth. However, in some cancer cells, oncolytic viruses are often limited in completing their full replication cycle, making progeny virions, and/or spread in the tumor bed due to the heterogeneous cell types within the tumor bed. Here we report that nuclear export pathway regulates oncolytic myxoma virus (MYXV) infection and cytoplasmic viral replication in a subclass of human cancer cell types where virus replication is restricted. Inhibition of CRM1/XPO-1 nuclear export pathway with nuclear export inhibitors can overcome this restriction by trapping restriction factors in the nucleus and allow significantly enhanced virus replication and killing of human cancer cells. Furthermore, knockdown of CRM1/XPO-1 significantly enhanced MYXV replication in restrictive human cancer cells and reduced the formation of anti-viral granules associated with RNA helicase DHX9. Both in vitro and in vivo, we demonstrate that the approved CRM1 inhibitor drug Selinexor enhances the replication of MYXV and cell killing of diverse human cancer cells. In the xenograft tumor model in NSG mice, combination therapy with Selinexor plus MYXV significantly reduced tumor burden and enhanced the survival of animals. Additionally, we performed global scale proteomic analysis of nuclear and cytosolic proteins in human cancer cells to identify the host and viral proteins that are upregulated or downregulated by different treatments. These results for the first time indicate that Selinexor in combination with oncolytic MYXV can be used as potential new anti-cancer therapy

microbiology↗

bioRxiv2021

Experimental investigations of the human oesophagus: anisotropic properties of the muscular layer in large deformation

Technological advancements in the field of robotics have led to endoscopic biopsy devices able to extract diseased tissue from between the layers of the gastrointestinal tract. Despite this, the layer-dependent properties of these tissues have yet to be mechanically characterised using human tissue. In this study, the ex vivo mechanical properties of the passive muscularis propia layer of the human oesophagus were extensively investigated. For this, a series of uniaxial tensile tests were conducted. The results displayed hyperelastic behaviour, while the differences between loading the tissue in both the longitudinal and circumferential directions showcased its anisotropy. The anisotropy of the muscular layer was present at different strain rates, with the longitudinal direction being consistently stiffer than the circumferential one. The circumferential direction was found to have little strain-rate dependency, while the longitudinal direction results suggest pronounced strain-rate-dependent behaviour. The repeated trials showed larger variation in terms of stress for a given strain in the longitudinal direction compared to the circumferential direction. The possible causes of variation between trials are discussed, and the experimental findings are linked to the histological analysis which was carried out via various staining methods. Finally, the direction-dependent experimental data was simulated using an anisotropic, hyperelastic model.

bioengineering↗

bioRxiv2020

Humans surviving cholera develop antibodies against Vibrio cholerae O-specific polysaccharide that inhibit pathogen motility

The mechanism of protection against cholera afforded by previous illness or vaccination is currently unknown. We have recently shown that antibodies targeting O-specific polysaccharide (OSP) of Vibrio cholerae correlate highly with protection against cholera. V. cholerae is highly motile and possesses a flagellum sheathed in O-specific polysaccharide (OSP), and motility of V. cholerae correlates with virulence. Using high speed video microscopy, and building upon previous animal-related work, we demonstrate that sera, polyclonal antibody fractions, and OSP-specific monoclonal antibodies recovered from humans surviving cholera block V. cholerae motility at both subagglutinating and agglutinating concentrations. This anti-motility effect is reversed by pre-adsorbing sera and polyclonal antibody fractions with purified OSP; and is associated with OSP-specific but not flagellin-specific monoclonal antibodies. F[ab] fragments of OSP-specific polyclonal antibodies do not inhibit motility, suggesting a requirement for antibody-mediated crosslinking in motility inhibition. We show that OSP-specific antibodies do not directly affect V. cholerae viability, but that OSP-specific monoclonal antibody highly protects against death in the murine cholera model. We used in vivo competitive index studies to demonstrate that OSP-specific antibodies impede colonization and survival of V. cholerae in intestinal tissues, and that this impact is motility-dependent. Our findings suggest that the impedance of motility by antibodies targeting V. cholerae OSP contributes to protection against cholera. IMPORTANCECholera is a severe dehydrating illness of humans caused by Vibrio cholerae. V. cholerae is a highly motile bacterium that has a single flagellum covered in lipopolysaccharide (LPS) displaying O-specific polysaccharide (OSP), and V. cholerae motility correlates with its ability to cause disease. The mechanisms of protection against cholera are not well understood; however, since V. cholerae is a non-invasive intestinal pathogen, it is likely that antibodies that bind the pathogen or its products in the intestinal lumen contribute to protection from infection. Here, we demonstrate that OSP-specific antibodies isolated from humans surviving cholera in Bangladesh inhibit V. cholerae motility and are associated with protection against challenge in a motility-dependent manner.

microbiology↗

bioRxiv2020

ZNF410 represses fetal globin by devoted control of CHD4/NuRD

Major effectors of adult-stage fetal globin silencing include the transcription factors (TFs) BCL11A and ZBTB7A/LRF and the NuRD chromatin complex, although each has potential on-target liabilities for rational {beta}-hemoglobinopathy therapeutic inhibition. Here through CRISPR screening we discover ZNF410 to be a novel fetal hemoglobin (HbF) repressing TF. ZNF410 does not bind directly to the{gamma} -globin genes but rather its chromatin occupancy is solely concentrated at CHD4, encoding the NuRD nucleosome remodeler, itself required for HbF repression. CHD4 has two ZNF410-bound regulatory elements with 27 combined ZNF410 binding motifs constituting unparalleled genomic clusters. These elements completely account for ZNF410s effects on{gamma} -globin repression. Knockout of ZNF410 reduces CHD4 by 60%, enough to substantially de-repress HbF while avoiding the cellular toxicity of complete CHD4 loss. Mice with constitutive deficiency of the homolog Zfp410 are born at expected Mendelian ratios with unremarkable hematology. ZNF410 is dispensable for human hematopoietic engraftment potential and erythroid maturation unlike known HbF repressors. These studies identify a new rational target for HbF induction for the {beta}-hemoglobin disorders with a wide therapeutic index. More broadly, ZNF410 represents a special class of gene regulator, a conserved transcription factor with singular devotion to regulation of a chromatin subcomplex.

genetics↗

bioRxiv2020

Association of poor virus specific immunoglobulin G antibodyresponses with higher viral load is seen in Bangladeshi pregnantwomen having acute Hepatitis E Genotype 1 infection

Although Hepatitis E viral illness is usually self-limiting, higher rates of morbidity and mortality are frequently observed during pregnancy in South Asian countries including Bangladesh. Of the four common variants, hepatitis E virus genotype 1 is mainly prevalent in South Asian countries. Pregnant women usually suffer from a state of immunosuppression. It is yet to be known whether virus specific immunoglobulin G (IgG) immune responses have any association with the vulnerability of pregnant women to acute hepatitis with E virus. The study aimed to compare the viral load and IgG responses of hepatitis E-infected pregnant women with that of non-pregnant women with same infection. Real Time -quantitative reverse transcription Polymerase Chain Reaction and Sanger sequencing were performed to determine the viral load and genotype, respectively, whereas Enzyme Linked Immunosorbent Assay method was used to determine hepatitis E virus specific serum IgG antibody index along with IgG avidity index. Although significant negative correlations were observed between log viral copy number and log IgG antibody index in the late acute phases of jaundice for both pregnant (r= -0.7971, p=0.0002) and non-pregnant women (r= -0.9117, p=0.0002), serum log viral copy number of pregnant women was significantly higher than that of the non-pregnant counterpart (p=0.0196) in the late acute stage of jaundice. In addition, log hepatitis E virus IgG antibody index of pregnant women was significantly lower than the non-pregnant women in the late phase of jaundice induced by hepatitis E virus (p=0.0303). Moreover, pregnant women with acute hepatitis E had higher cross-reactive IgG than in the non-pregnant women (p=0.0017). All the patients got infected with hepatitis E virus were in Genotype 1 variety. The study demonstrates that virus-specific poor IgG responses might be responsible for vulnerability of pregnant women to acute hepatitis with hepatitis E virus. Author SummaryAcute hepatitis caused by hepatitis E virus (HEV) Genotype 1 is a public health problem in Asian countries and especially it poses a potential health threat to pregnant women causing 19% to 25% mortality, particularly in South Asian countries including Bangladesh. The study aimed to explore whether HEV IgG immune responses were compromised during pregnancy, which might contribute to higher viral load and disease severity. Accordingly, pregnant and non-pregnant women with acute hepatitis (clinically presented with nausea, loss of appetite and /or jaundice) were enrolled from different tertiary care hospitals in Dhaka city. All these patients were screened and hepatitis E were differentiated from other hepatitis (caused by A, B, C) using Enzyme Linked Immunosorbent Assay (ELISA) methods. HEV IgG antibody/avidity indices and viral loads were measured using ELISA and real time quantitative polymerase chain reaction (RT-qPCR), respectively. The study showed that pregnant women with acute hepatitis E had lower IgG indices with higher viral load than their non-pregnant counterpart. Overall, the study revealed that virus-specific poor IgG responses might render pregnant women vulnerable to acute hepatitis E of varying degree of severity which might be associated with higher viral load.

immunology↗

bioRxiv2020

Investigation the biomass conversion efficiency, biochemical characterisation and structural insights of the newly isolated AA16 family of Lytic Polysaccharide Monooxygenase (LPMO) from Aspergillus fumigatus

The efficient conversion of lignocellulosic biomass into fermentable sugar is a bottleneck for the cheap production of bio-ethanol. The recently identified enzyme Lytic Polysaccharide Monooxygenase (LPMO) family has brought new hope because of its boosting capabilities of cellulose hydrolysis. In this report, we have identified and characterized a new class of auxiliary (AA16) oxidative enzyme LPMO from the genome of a locally isolated thermophilic fungus Aspergillus fumigatus (NITDGPKA3) and evaluated its boosting capacity of biomass hydrolysis. The AfLPMO16 is an intronless gene and encodes the 29kDa protein. While Sequence-wise, it is close to the C1 type of AaAA16 and cellulose-active AA10 family of LPMOs, but the predicted three-dimensional structure shows the resemblance with the AA11 family of LPMO (PDB Id: 4MAH). The gene was expressed under an inducible promoter (AOX1) with C-terminal His tag in the Pichia pastoris. The protein was purified using Ni-NTA affinity chromatography, and we studied the enzyme kinetics with 2,6-dimethoxyphenol. We observed polysaccharides depolymerization activity with Carboxymethyl cellulose (CMC) and Phosphoric acid swollen cellulose (PASC). Moreover, the simultaneous use of cellulase cocktail (commercial) and AfLPMO16 enhances lignocellulosic biomass hydrolysis by 2-fold, which is highest so far reported in the LPMO family. ImportanceThe auxiliary enzymes, such as LPMOs, have industrial importance. These enzymes are used in cellulolytic enzyme cocktail due to their synergistic effect along with cellulases. In our study, we have biochemically and functionally characterized the new AA16 family of LPMO from Aspergillus fumigatus (NITDGPKA3). The biochemical characterization is the fundamental scientific elucidation of the newly isolated enzyme. The functional characterization, biomass degradation activity of AfLPMO16, and cellulase cocktail (commercial) combination enhancing the activity by 2-fold. This enhancement is the highest reported so far, which gives the enzyme AfLPMO16 enormous potential for industrial use.

biochemistry↗

bioRxiv2020

Selective LXR agonist, DMHCA, corrects the retina-bone marrow axis in type 2 diabetes

In diabetic dyslipidemia, cholesterol accumulates in the plasma membrane, decreasing fluidity and thereby suppressing the ability of cells to transduce ligand-activated signaling pathways. Liver X receptors (LXRs) are the main cellular mechanism by which intracellular cholesterol is regulated and play important roles in inflammation and disease pathogenesis. N,N-dimethyl-3{beta}-hydroxy-cholenamide (DMHCA), a selective LXR agonist, specifically activates the cholesterol efflux arm of the LXR pathway without stimulating triglyceride synthesis. Thus, DMHCA possesses superior clinical potential as a cholesterol lowering agent than current LXR pan-agonist. In this study, we use a multi-systems approach to understand the effects and molecular mechanisms of DMHCA treatment in type 2 diabetic db/db mice and human -derived circulating angiogenic cells (CACs), which are vascular reparative cells. We find that DMHCA is sufficient to correct the retina-bone marrow (BM) axis in diabetes, thereby restoring retinal structure, function, and cholesterol homeostasis, rejuvenating membrane fluidity in circulating vascular reparative cells, hampering systemic inflammation, and correcting BM dysfunction. Using single-cell RNA-seq on lineage-sca1+cKit+ (LSK) hematopoietic stem cells (HSCs) from untreated and DMHCA-treated diabetic mice, we provide novel insights into hematopoiesis and reveal DMHCAs mechanism of action in correcting diabetic HSCs by reducing myeloidosis and increasing CACs and erythrocyte progenitors. Taken together, these findings demonstrate the broad and pleiotropic effects of DMHCA treatment, which has exciting potential to correct the retina-BM axis in diabetic subjects.

cell biology↗

bioRxiv2019

Cyclin binding Cy motifs have multiple activities in the initiation of DNA replication

The initiation of DNA replication involves the cell cycle-dependent assembly and disassembly of protein complexes, including the Origin Recognition Complex (ORC) and CDC6 AAA+ ATPases. We report that multiple short, linear protein motifs (SLiMs) within intrinsically disordered regions in ORC1 and CDC6, including Cyclin-binding (Cy) motifs, mediate Cyclin-CDK dependent and independent protein-protein interactions, conditional on cell cycle phase. The ORC1 Cy motif mediates an auto-regulatory self-interaction, and the same Cy motif prevents CDC6 binding to ORC1 in mitosis, but then facilitates the destruction of ORC1 in S phase. In contrast, in G1, the CDC6 Cy motif promotes ORC1-CDC6 interaction independent of Cyclin-CDK protein phosphorylation. CDC6 interaction with ORC also requires a basic region of ORC1 that in yeast mediates ORC-DNA interactions. We also demonstrate that protein phosphatase 1 binds directly to a SLiM in ORC1, causing de-phosphorylation upon mitotic exit. Thus, Cy-motifs have wider roles, functioning as a ligand and as a degron.

molecular biology↗

bioRxiv2019

Antitumor effects of Tv1 venom peptide in liver cancer

A strategy for treating the most common type of liver cancer, hepatocellular carcinoma (HCC) applies a targeted therapy using venom peptides that are selective for ion channels and transporters overexpressed in tumor cells. Here, we report selective anti-HCC properties of Tv1, a venom peptide from the predatory marine terebrid snail, Terebra variegata. Tv1 was applied in vitro to liver cancer cells and administered in vivo to allograft tumor mouse models. Tv1 inhibited the proliferation of murine HCC cells via calcium dependent apoptosis resulting from down-regulation of the cyclooxygenase-2 (COX-2) pathway. Additionally, tumor sizes were significantly reduced in Tv1-treated syngeneic tumor-bearing mice. Tv1s mechanism of action involves binding to specific transient receptor potential (TRP) cation channels that are overexpressed in HCC cell models. Our findings demonstrate the unique potential of venom peptides to function as tumor specific ligands in the quest for targeted cancer therapies.

cancer biology↗

bioRxiv2019

BDNF/TrkB.T1 signaling is a novel mechanism for astrocyte morphological maturation

Brain derived neurotrophic factor (BDNF) is a critical growth factor involved in the maturation of neurons, including neuronal morphology and synapse refinement. Herein, we demonstrate astrocytes express high levels of BDNFs receptor, TrkB (in the top 20 of protein-coding transcripts), with nearly exclusive expression of the truncated isoform, TrkB.T1 which peaks in expression during astrocyte morphological maturation. Using a novel culture paradigm, we show that astrocyte morphological complexity is increased in the presence of BDNF and is dependent upon BDNF/TrkB.T1 signaling. Deletion of TrkB.T1 in vivo revealed morphologically immature astrocytes with significantly reduced volume and branching, as well as dysregulated expression of perisynaptic genes associated with mature astrocyte functions, including synaptogenic genes. Indicating a role for functional astrocyte maturation via BDNF/TrkB.T1 signaling, TrkB.T1 KO astrocytes do not support normal excitatory synaptogenesis. These data suggest a significant role for BDNF/TrkB.T1 signaling in astrocyte morphological maturation, a critical process for CNS development.

neuroscience↗