Sougata Roy Chowdhury

Enhancement of tensile strength of lignocellulosic jute fibers by alkali-steam treatment.

The physico-chemical properties of jute fibers treated with alkali (NaOH) solution have been investigated in this study. The treatments were applied under ambient and elevated temperatures and high pressure steaming conditions. To the knowledge of these authors the influence of alkali-steam treatment on the uniaxial tensile strength of natural ligno-cellulosic fibers, such as jute, has not been investigated earlier. The results from this investigation indicate that a 30 min dipping of the fibers in 0.5% alkali solution followed by 30 min alkali-steam treatment leads to an increase in the tensile strength of up to 65%. The increase appears to be due to fiber separation and removal of non-cellulosic materials, which, in turn, resulted in an increased crystallinity.

Composition analysis and material characterization of an emulsifying extracellular polysaccharide (EPS) produced by Bacillus megaterium RB-05: a hydrodynamic sediment-attached isolate of freshwater origin.

Aims:  This work was aimed to isolate, purify and characterize an extracellular polysaccharide (EPS) produced by a freshwater dynamic sediment‐attached micro‐organism, Bacillus megaterium RB‐05, and study its emulsifying potential in different hydrocarbon media.

Low fucose containing bacterial polysaccharide facilitate mitochondria-dependent ROS-induced apoptosis of human lung epithelial carcinoma via controlled regulation of MAPKs-mediated Nrf2/Keap1 homeostasis signaling

Reactive oxygen species (ROS), the key mediators of cellular oxidative stress and redox dysregulation involved in cancer initiation and progression, have recently emerged as promising targets for anticancer drug discovery. Continuous free radical assault upsets homeostasis in cellular redox system and regulates the associated signaling pathways to mediate stress‐induced cell death. This study investigates the dose‐specific pro‐oxidative behavior of a bacterial fucose polysaccharide, which attenuated proliferation of different cancer cells. In the fermentation process, Bacillus megaterium RB‐05 [GenBank Accession Number HM371417] was found to biosynthesize a polysaccharide with low‐fucose content (4.9%), which conferred the maximum anti‐proliferative activity (750 µg/mL) against human lung cancer epithelial cells (A549) during preliminary screening. Structural elucidation and morphological characterization of the duly purified polysaccharide was done using HPLC, GC‐MS, 1H/13C NMR, and microscopy. The polysaccharide exhibited concentration‐ and time‐dependent anti‐proliferative effects against A549 cells by inducing intracellular ROS level and regulating the mitochondrial membrane‐permeability following the apoptotic pathway. This process encompasses activation of caspase‐8/9/3/7, increase in the ratio of Bax/Bcl2 ratio, translocation of Bcl2‐associated X protein (Bax) and cytochrome c, decrease in expression of anti‐apoptotic members of Bcl2 family, and phosphorylation of mitogen activated protein kinases (MAPKs). Apoptosis was attenuated upon pretreatment with specific caspase‐inhibitors. Simultaneously, during apoptosis, the ROS‐mediated stress as well as activated MAPKs triggered nuclear translocation of transcription factors like nuclear factor (erythroid‐derived)‐like 2 (Nrf2) and promoted further transcription of downstream cytoprotective genes, which somehow perturbed the chemotherapeutic efficacy of the polysaccharide, although using CuPP, a chemical inhibitor of HO‐1, apoptosis increased significantly (P < 0.05).

Characterization and emulsifying property of a carbohydrate polymer produced by Bacillus pumilus UW-02 isolated from waste water irrigated agricultural soil

Bacillus pumilus UW-02, an isolate from agricultural soil irrigated with waste water was found to produce a carbohydrate polymer in the form of extracellular polysaccharide (EPS) in glucose mineral salts medium (GMSM). The recovery rates of EPS by ion-exchange and gel filtration chromatography were around 63% and 90%, respectively. As evident from HPLC and FT-IR analyses, the EPS was found to be a heteropolymer consisting glucose, mannose, xylose, arabinose, and N-acetyl glucosamine as monomer units. Different oligosaccharide combinations namely hexose(4), hexose(6) pentose(1) and hexose(10) pentose(1) are obtained after partial hydrolysis of EPS using MALDI-ToF-MS. Electron micrographs portrayed the intense affinity of the EPS molecules for each other, thereby justifying its viscosifying and thickening properties. The EPS with an average molecular weight of 218 kDa and thermal stability up to 180 °C showed pseudoplastic rheology and significant emulsifying activities.

Electrospun chitosan/polycaprolactone-hyaluronic acid bilayered scaffold for potential wound healing applications

Fabrication of mechanically stable, biocompatible bilayered polymeric scaffold consisting of chitosan(CS)/polycaprolactone(PCL) and hyaluronic acid(HA) using less toxic solvent system is presented in this study. Electrospinning technique to make the scaffold was used followed by morphological, physiochemical and mechanical characterizations. Average fiber diameter of CS/PCL-HA bilayered scaffold was found 362.2 ± 236 nm which is in the range of collagen fiber found in the extracellular matrices. Enhanced swelling, degradation, hydrophilicity and water vapour transmission rate were found for the bilayered scaffold compared to that of the PCL and CS-PCL scaffolds. Antimicrobial property evaluation revealed reduction in bacterial adhesion on bilayered scaffolds. Invitro studies with vero cells [kidney epithelial cell, extracted from African Green Monkey (Chlorocebus sp.)] confirm enhanced proliferation, growth and migration of vero cell on the bilayered CS/PCL-HA scaffold to that of PCL and CS/PCL scaffolds. Novelty of this study includes the use of HA for mechanically stabilized scaffold with acceptable biological properties for wound healing applications.

Abstract 943: RelA regulates CXCR5/CXCL13 transcription and associated immune response in breast cancer

It is evident from research outcomes that metastases-associated deaths are predominant in breast cancer. Recent developments on early diagnosis using mammographic screening and the implementation of adjuvant therapies may have reduced breast cancer associated deaths in decent numbers, although new markers for prognosis are of utmost importance for patients with higher risk of developing metastases or recurrence. Chemokines are the key messenger of cellular immune response and can be targeted to reduce the intratumoral regulatory T cells (Treg) for antitumor immunity. Targeting either specific immunomodulators and/or intervening molecular mechanisms is thought to be a potential therapeutic option. In our previous study, we have found that co-expression of CXCR5 and CXCL13 is significantly associated with epithelial to mesenchymal transition (EMT) of cells and lymph node metastasis (LNM) during breast cancer progression. In this study, we are aiming to investigate how the transcriptional regulation of this receptor-ligand pair directs the process of disease development. Interestingly, it was found that RelA (p65), a subunit of NFkB protein, promoted the transcription of both CXCR5 and CXCL13. The putative RelA binding sites were validated using sequential deletion of respective promoter regions of CXCR5 and CXCL13. We observed that expression of CXCR5 significantly (p The study may help to understand the prognosis value of CXCR5 and CXCL13 considering the impact of this receptor-ligand pair on the regulation of Tfh/Treg ratio, EMT and LNM. We believe that this investigation may lead to a comprehensive prediction of the tumor fate as well as to explore possible markers for breast cancer prognosis and future chemotherapy with more precision. Citation Format: Sougata Roy Chowdhury, Subir Biswas, Gunjan Mandal, Arindam Bhattacharyya. RelA regulates CXCR5/CXCL13 transcription and associated immune response in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 943. doi:10.1158/1538-7445.AM2017-943