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Item Selection of high yielding elite chemotypes of paclitaxel producing Himalayan yew (Taxus wallichiana) from different geographical regions of the HimalayasDey, AbhijitTaxus wallichiana Zucc. (synonym Taxus baccata subsp. wallichiana (Zucc.) Pilg.) or Himalayan yew, has drawn a lot of interest globally. This is mostly attributed to its remarkable abundance of paclitaxel, an exceptionally potent anti-cancer drug, as well as various other significant secondary metabolites. Paclitaxel, commercially known as Taxol®, has demonstrated efficacy in treating several types of cancers including breast, cervical, head, lung, neck, ovarian, urothelial carcinoma. All taxa under the genus Taxus, including T. wallichiana, have slow growth rate over annually. Consequently, the extraction and isolation of paclitaxel from Himalayan yew for industrial applications pose significant challenges due to its limited presence in the bark, stem, and needles. The cost of paclitaxel has increased due to a combination of factors including its limited availability and growing demand in cancer therapy. The major goal of this research is to quantify the marker component, paclitaxel, which is extracted from Himalayan yew samples obtained from different locations. The goal is to find the most effective chemotypes of Himalayan yew based on different altitude in the Himalayan region. Furthermore, the current study aims to find other phytochemical compounds. The aim of this research is to establish a standardized and verified HPTLC (high performance thin layer chromatography) procedure for the quantitative measurement of marker anticancer compound paclitaxel. Furthermore, the study also encompasses a comprehensive analysis of antioxidant and toxicological study of various plant extracts. This investigation conducted in the selected region will significantly contribute to the scientific application and exploitation of these findings.Item Structural and Biochemical characterization of a class III sirtuin, OsCobB in Oryza sativa indica and its association to stress response in plantsDey, SanghamitraSirtuins have attained recognition in the sphere of epigenetic regulation, owing to its affiliation with numerous biological processes including metabolism and genomic stability. Many post translational modifications (PTMs) are controlled by these sirtuins, playing critical roles in escaping abiotic and biotic stresses, although their pattern in plants have been poorly understood. In our investigation, a novel class III sirtuin has been discovered in Oryza sativa var indica with a high sequence identity with bacterial CobB. No class III sirtuins have been reported in plants till this study. Correlating molecular docking analysis with in-vitro and in-vivo deacylation assays helped in the understanding of various aspects of enzymatic mechanisms of OsCobB. We identified the important motifs for substrate and NAD+ binding like GAGISA, FGE, YXXR and TQNID, which were unique to class III sirtuin family. Although all modifications could be accommodated at the catalytic site, its selectivity also depended on the orientation of the peptide backbone and its interaction (bonded and non-bonded) with the sirtuin. OsCobB had a preference for the negatively charged lysine modifications like malonyl, succinyl and glutaryl through H-bonds with conserved YXXR motif. OsCobB can also accommodate the longer acyl modifications like myristoyl by a possible shift of its α4 helix. It was also established that an initial attachment of its co-substrate, NAD+ was mandatory to facilitate a conformational change for the correct binding of the peptide. In contrast to some class III members, OsCobB didnot exhibit any ADP-ribosyl transferase activity. We have identified this sirtuin to be majorly localized in the mitochondria with trace amounts in the nucleus. However, the preferential localization of this protein in the nucleus in response to low temperature and dehydration conditions could be related to its functioning. Histones (H3 and H4) as well as ACS were identified as the nuclear targets for this enzyme. Though OsCobB was incapable of efficiently deacetylating histone H4, it could deacetylate H3 at K9 and K18 residues. To cope with dehydration, OsCobB was capable of regulating the metabolism by removing different acyl groups like succinyl in H4 and butyryl, HIB and BHB in H3. Arsenic toxicity in the soil was also linked to OsCobB catalyzed H3 demalonylation and H4 desuccinylation. This enzyme was also capable of modulating mitochondrial ACS and IDH2 activity, favouring its deglutarylation and desuccinylation. This is the first mitochondrial CobB targeting important plant machinery under pathogen attack. NAD+ could be replaced by NADP+ as a cosubstrate in deacetylation reaction. OsCobB activity is insensitive to its product, NAM while showing sensitivity towards Fe2+ and Mn2+ ions. All-inclusive, this study discovered the catalytic abilities of rice class III sirtuin in conjunction with their substrates. A correlation between OsCobB overexpression and its preferential removal of lysine modifications on target substrates may hint at its regulation under stress.Item Studies on the conformational dynamics of HIV-1 accessory proteins to guide new therapeutic developmentGiri, KalyanThe HIV-1 accessory proteins (Vpr, Vif, Vpu, and Nef) are multifunctional proteins that play a critical role in the virus progression and contributing to AIDS pathogenesis. These proteins engage with numerous host cellular proteins to execute various functions, promoting viral replication. These proteins show remarkable conformational plasticity i.e. they frequently undergo substantial structural changes upon binding to their targets. In this research, conformational dynamics of these proteins are thoroughly investigated thorough integrated computational modelling and molecular dynamics (MD) simulation techniques in order to explain functional mechanisms and most importantly to explore druggability against these proteins. Conformational analysis revealed novel insights into Vpr's conformational space, particularly the stable embedding of the Vpr C-terminal helix (residues 54-77) within lipid bilayers, marking its likely role as the transmembrane core of the ion channel structure. Full length Vpr undergoes large structural deviations inside lipid bilayer resulting in novel conformations of Vpr. The proposed multimeric Vpr ion channel models in this research offered the first rational attempt for structural understanding of this oligomeric complex which could enhance the therapeutic options. On the other hand, Viprinin and its two potent derivatives emerged as effective inhibitors for Vpr. These findings provide pivotal insights into structure-based drug discovery efforts against HIV-1 accessory proteins. The proposed ion channel models and inhibitor compounds establish a computational framework for future investigations into HIV-1 Vpr structural biology and drug development. Additionally, the analysis of Nef's conformational space identified a conserved druggable pocket implicated in homodimerization, presenting a potential therapeutic target. Utilizing fragment-based approaches, novel lead compounds against Nef were generated and further optimized through advanced MD simulations. These compounds could serve as the starting point for initial stage clinical trials for the discovery of new antiretroviral compounds targeting Nef. This research will lead to development of novel therapeutic options to combat HIV-1 infection in forseeable future in turn leading to significant decrease in loss of lives due to AIDS.Item Deciphering micro/nanoplastic induced phytotoxicity with special emphasis on the cytogenotoxic effects on Allium cepa L.Pramanick, KousikConsidering the present plastic pollution crisis, this thesis work reported the phytotoxicity of polystyrene micro/nanoplastics (M/NPs) in onion with effects on seed germination, root growth, and cytotogenotoxicity. The detection of negative impacts in environmentally relevant concentrations of polystyrenes (PS) clearly showed the harmful effects of polystyrene particles on the plants health, indicating its possible negative impacts on biodiversity. The root growth rather than seed germination was negatively affected by the increasing concentrations of polystyrene particles. The tested diameter of polystyrene particles caused an imbalance in redox homeostasis through the elevated production of ROS, which in high concentrations of polystyrenes subdues the antioxidant defence and ensues in different harmful effects. Different chromosomal alterations and DNA damage potential of micro/nanopolystyrenes (M/NPS), as recorded in this work, may indicate the potential threat of micro/nanoplastics to other organisms because, the basic genetic makeup is same for all eukaryotes. The combined effects of nanoplastics and heavy metals such as Cd and Hg were also evaluated showing an increasing level of toxicity of Cd and a decreasing toxicity of Hg in the presence of polystyrene particles. This observation signifies a differential effect of plastics in modulating the toxicities of heavy metals depending on metal species. Another interesting finding of this work was the positive impact of high temperature or temperature stress (TS), but not the salinity stress (SS), in aggravating the toxicity of micro/nanoplastics. The temperature stress improves the root accumulation of polystyrene particles with notable deleterious effects on oxidative stress, microtubules stability, and organization. In this study, we have used the term micropolystyrene and nanopolystyrene interchangeably for the same diameter (100 nm or 0.1 µm) of polystyrene particles, because the selected diameter remains at the transition between micro and nano particles and there is no accepted distinction on nanoplastics size unlike metal nanoparticles. Some authors have used the term micro for this diameter, while others have used nano for the same.Item Identification of candidate tumor suppressor genes’ loci on chromosome 9 associated with the development of arsenic induced urinary bladder cancer in West Bengal, IndiaGhosh, AmlanThe etiological link of arsenic with bladder cancer (BC) is well established across the globe. The molecular pathogenesis of arsenic induced BC should be explored to identify potential markers of clinical importance for better disease management. Arsenic toxicity is a burning health issue along Gangetic belt of West Bengal and higher BC incidence was recorded in affected areas of the state than safe areas. On this background, present hospital-based study aimed to analyse the association of arsenic with development/progression/prognosis of BC in West Bengal and, explore molecular pathogenesis of arsenic-induced BC targeting candidate tumor suppressor genes (TSGs) of chromosome-9 due to previous reports of alteration of the chromosome in BC. In this hospital-based study, majority of BC patients were documented from arsenic affected areas of the state and in these patients, concordantly high tumor arsenic level (AsH, >100 ppb) was detected. High tumor arsenic level was found to be associated with higher proliferation potential (assessed by immunohistochemical analysis of ki67) and pathological stages of tumor and poor patient survival. Thus, in exposed individuals, arsenic accumulates in bladder tissue to influence tumorigenesis and favour acquisition of aggressive tumor phenotypes that affect disease outcome. To explore molecular pathogenesis, 9p22-21 and 9q22.3 were selected based on previous report and candidate TSGs deleted in these regions in AsH tumors were detected by analysing whole genome CGH+SNP array data of our previous study. In 9p22 region, SH3GL2 (SH3 domain containing GRB2 like 2) showed molecular alteration (deletion & promoter methylation) preferably in AsH tumors similar to array based data and, concordant reduced expression. SH3GL2 inactivation seemed to affect receptor mediated endocytosis of active EGFR as evident from overexpression of the later without any amplification of gene in same sample set. SH3GL2 inactivation and associated dysregulation in “negative regulation of ERBB signalling pathway” was seen to have prognostic significance. In 9q22.3 region, deletion, promoter methylation, and concordant reduced expression of PHF2 was seen preferentially in AsH tumors. PHF2 (PHD finger protein 2) involves in “histone lysine (H3K9me2) demethylation pathway” essential for p53 functioning. In present study, PHF2 inactivation might affect p53 mediated transcription as evident from reduced p21 expression in same set of tumors over- expressing p53 protein. CDKN2A and CDKN2B loci from 9p21 region, FANCC and PTCH1 loci from 9q22.3 region were also analysed in this study. As evident from comparable and high frequency of molecular alteration in AsH and AsL (arsenic low; ≤100 ppb) tumors, the gene loci did not seem to have important contribution in pathogenesis of arsenic induced BC. The information on association of arsenic with disease progression, prognosis and related molecular pathogenesis will have implementation in designing preventive and management strategies for arsenic induced bladder cancer in future.Item Assessment of fluoride induced male reproductive disorders in adult Wistar rats and its amelioration by supplementation of vitamin C and EMukhopadhyay, Prabir KrFluoride is necessary for tooth and bone development, but excessive exposure causes different system disorders including male reprotoxic consequences. The purpose of this study was to investigate the extent of fluoride toxicities in the male reproductive system and its possible management by vitamin C and E. The study was undertaken to find out the optimum dose of fluoride responsible for causing considerable reprotoxic effects in adult male Wistar rats. The rats were divided into four groups; control (group I) rats received vehicle only and treated rats (group II, III, and IV) were administered sodium fluoride (NaF) orally at 10, 15, and 20 mg/kg/day doses, respectively, for 30 consecutive days. Assessments were done on the following parameters: histoarchitecture of testis and epididymis; spermatozoal potential and DNA integrity; testicular oxidative status, activities of functional marker enzymes and DNA integrity. All these parameters were altered in a dose-dependent manner and based on these; 15 mg/kg/day was selected as the minimum dose responsible for considerable alterations. Further experiments were carried out with this dose. The protective role of VC&VE was assessed on different animal models. Rats were divided into four groups. Group I was the control; Group II received NaF at 15 mg/kg/day dose; Group III was provided with VC (200 mg/kg/day) and VE (400 mg/kg/day) along with NaF; Group IV received only VC&VE for 30 consecutive days. The following studies were undertaken: structure-function integrity of testis, epididymis and spermatozoa; oxidative status of testis and epididymis; testicular functional and steroidogenic status; apoptotic pathway of testis and epididymis; testicular inflammatory status along with spermatozoal apoptotic state. All these parameters were altered due to the fluoride threat. Supplementation with VC&VE restored all the anomalies either to normal or near normal levels. The group IV rats showed a similar pattern of the results to the group I rats.Item Screening of bamboo species available in West Bengal, India to assess their utility as lignocellulosic biomass resourcesDas, MalayBamboos, a category of non-timber grasses, belong to the family Poaceae and the subfamily Bambusoideae. Therefore, phylogenetically they are close to rice (Oryza sativa), Brachypodium and other reference grasses. It has immense potential for the ligno-cellulose biomass (LCB) based biofuel industry primarily due to their high growth rate, which leads to rapid accumulation of LCBs, high fibre contents, requirement of less agronomic input, existence of a wide genetic pool, and having no conflict with food crops. Despite this, there haven't been sufficient investigations to study the biology of cellulose and lignin deposition in tree bamboos. There remains a serious dearth of understanding, in particular, with respect to varying cellulose and lignin levels that exist at the germplasm/population level. Therefore, in this study, seven abundantly growing and widely distributed bamboo species of West Bengal, India, namely Bambusa balcooa, B. tulda, B. bambos, B. nutans, B. striata, Dendrocalamus giganteus, and D. strictus were investigated to assess their potential as LCB donors. In order to determine the chemical composition of LCBs obtained from the internode tissues of these species, this study utilized physico-chemical techniques such as, Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) Spectroscopy, Thermal Gravimetric Analysis (TGA), X-ray diffraction (XRD), biochemical assessments of α-cellulose, lignin levels and important anatomical features with major emphasis on the vascular bundles. Findings of this study indicated that analysing intensity of stain specific for cellulose and lignin could be a useful, yet cheap marker to screen a big collection of bamboo species and germplasms in order to identify superior species/genotype having potential for the liquid, biofuel industry. Collective analysis of all these parameters have identified B. bambos as the reference bamboo species having enormous prospects for future biomass based bioenergy production. . Also, in this study, three Cellulose Synthesis A (CesA) genes possibly associated with secondary cell wall formation had been identified and sequence characterized from the tropical bamboo B. tulda. Expression characterization from selected, vegetative tissues and developmental tissue stages indicate that they might be good candidate for future investigation to obtain bio stock having enhanced biomass accumulation. Collectively, this study developed an integrated strategy that might be utilized in future on other plants having similar biomass based bioenergy potential.Item A multibiomarker study to delineate the effects of environmental stressors on aquatic shellfishes of West BengalMandal, SumitOver the past decade a great attention has been paid to decipher the consequences of impending climate change scenario on the physiological and biochemical functioning of aquatic organisms. Anthropogenic activities primarily combustion of fossil fuel is the prime cause behind the increased concentration of CO2 into the atmosphere. As a consequence, marine environments are anticipated to experience more shift towards lower pH (ocean acidification) and elevated temperatures (ocean warming). Global climate change induced ocean warming and acidification have complex reverberation on physiological functioning of marine ectotherms. Moreover, since the industrial revolution the growing demand for petroleum-based products has been mounting up worldwide leading to severe oil pollution. Widespread use of pesticides in modern agricultural system has a significant contribution in polluting aquatic habitats across the world; and enclosed freshwater ecosystem being the ultimate receptacle is at great risk. In recent years, application of nanotechnology also has become more widespread and nanomaterials are constantly being released into aquatic environments and posing a potential risk to various organisms and ecosystems. Research works merging climate change stressors and incipient chemical pollutants are imperative to better comprehend and interpret biological effects in altering aquatic habitat. Environmental factors and pollution generally do not act in isolation, but usually perform collectively. Several researches have recognized the discrete effects of these drivers on species and ecosystems separately but studies regarding the interactive effects of multiple drivers are scarce. Animal physiologists have now unambiguously recognized the fact that anticipated climatic vicissitudes will impose noteworthy consequences on physiological functioning of most species. Ectotherms are of specific interest as their physiology principally relies on the external environment. The purpose of present study was to compare and decipher the impacts of multiple stressors and specifically whether global environmental drivers aggravate the effects of a local driver (pollution) on physiological energetics and antioxidant responses of two economically significant shellfishes from West Bengal. Two species from two different ecosystems- freshwater and estuarine were studied to compare and decode the ecological functioning of these realms distinctly. Multiple biomarkers from different levels of biological strata (physiological energetics, energy budget, thermal performance, antioxidant and detoxification defence mechanisms, lipid peroxidation levels, DNA damage) of the species were evaluated to understand responses. Stress levels were amalgamated from individual biomarker responses using an “Integrated Biomarker Response (IBR)” approach. The present doctoral work can provide an outline for more integrated management of commercially exploited shellfish populations, and shed light into coastal fisheries and aquaculture prospects in the impending future.Item Quantification of oxidative stress and physiological parameters due to schoolbag carriage in normal, overweight/obese male schoolchildren of West BengalMukhopadhyay, AparnaBackground: The physical activity of schoolbag carriage is a form of mandatory load carriage with a myriad of physiological consequences, the most common being pain occurrence and changes in physiological responses. The cardio-pulmonary response to a physical activity is dependent on its intensity which translates to weight of schoolbag being carried. The response to each physical activity is also dependent on the fat or lean body mass (body composition) of the individual performing it. Response to physical activity in subjects with an abundance of body fat is also concurrent with development of oxidative stress in the body. So, it is hypothesised that schoolbag carriage engenders different physiological response in terms of cardio-pulmonary, pain, postural and oxidative stress response in children belonging to different categories of body mass index (BMI). Methodology: Parental survey about awareness regarding behaviour and practices of their children with respect to schoolbag carriage was assessed by survey sheets. Anthropometric measurements for schoolchildren (males aged 10-15 years, n=60) were recorded and they were categorised into normal and overweight/obese BMI groups. They walked for 20-minutes with backpacks of varying weight (0%, 4%, 8%, 12% and 16% of bodyweight) during which their cardio-pulmonary parameters were assessed via COSMED k4b2. During the walks, pain reports for the entire body were mapped. The walks were video-graphed for analysis of postural undulations. Cognitive ability was assessed by ruler drop test (RDT). Before and after each walk, saliva collection was accomplished via passive drooling and the collected bio-fluid was assayed for biomarkers pertinent to oxidative stress. The parameters studied were evaluated for continuity, distribution and comparison was then further conducted by parametric or non-parametric tests whichever applicable. A mathematical model predicting the percentage change in antioxidant capacity using standardized pain, load of schoolbag carried and BMI as the predictors was developed employing linear regression. Results: Parental reports suggested that children carried heavy schoolbags in general and complained of pain causing high discomfort in neck, shoulder and back region. Majority of the parents never received any recommendations about safe load limits. All recorded anthropometric measurements for the age matched BMI categories were significantly higher (p<0.05) in overweight/obese BMI category compared to the normal category. During schoolbag carriage, heart regulation was better in case of normal BMI individuals. The lung volumes and energy expenditure were higher in overweight/obese participants (p<0.05). Cognition improved in children with normal BMI after carrying lower weight backpacks. The pain perceived was highest in the neck, shoulder and back region with shoulder. Pain perceived was higher in overweight/obese children. Posture worsened over time, and the postural undulations were more deleterious in overweight/obese children. Antioxidant status improved after carrying lower weight schoolbags. Nitric oxide mediated vasodilation was comparable in both BMI groups. The pain perception, load of schoolbag carried and BMI successfully predicted the percentage change in non-enzymatic antioxidant capacity via significant (p<0.05) mathematical regression model. Conclusion: For the same physiological load of schoolbag carried, the overweight/obese children are relatively inefficient in regulating their cardio-pulmonary responses, they suffered from higher cognitive and postural decline besides developing greater oxidative stress compared to their age-matched normal BMI counterparts. The load limit of schoolbag pertaining to 8% and 4% load of bodyweight is recommended for normal BMI and overweight/obese children based on the cumulative results on all parameters studied. The prediction equation developed realises the customized determination of safe load limit in every child. This study can be used by policy makers to formulate schoolbag load limit recommendations keeping in mind the BMI of children thus ameliorating the derogatory effects of carrying heavy schoolbags in children and safeguarding child health.Item Functional role of Interleukin-6 and Interleukin-10 in the reproductive processes of a teleost fish, Anabas testudineusPramanick, KousikIn mammals, interleukin-6 (IL-6) and interleukin-10 (IL-10) has an important function during the reproductive processes, however, the functions of IL-6 and IL-10 in fish have not been elucidated. In the present study, there was quantification of de novo synthesis of ovarian IL-6, IL-10 and tumor necrosis factor-alpha (TNFα) in control and hCG treated fish and results were compared with those from an in vitro study where there was evaluation of the regulatory functions of gonadotropins and TNFα of IL-6 and Il-10 secretions. Relatively greater concentrations of ovarian IL-6 at the post-GVBD (post-germinal vesicle breakdown) stage and higher concentration of ovarian IL-10 in post vitellogenic (PV) and post-GVBD stages indicates IL-6 and IL-10 can modulates reproductive processes. The hCG-induced increase in relative abundance of IL-6 and IL-10 (in vitro) mRNA transcript and secretion from the ovary were attenuated when there was administration of the inhibitor of TNF-α secreting enzyme, TAPI-I, which indicates TNF-α modulates IL-6 secretion and facilitate the production of IL-10. Treatments with IL-6 induced a marked increase in ovulation rate but there was no direct involvement of IL-10 during the time of maturation and ovulation. In vitro established that Il-6 induced ovulation by activating matrix metalloproteinase (MMP). Furthermore, treatment with IL-6 resulted in production of prostaglandin as indicated by the IL-6 induced increase in the abundance of ptgs2 mRNA transcript in the ovary of Anabas testudineus. IL-10 during this process mostly play the regulatory role of the cytokine environment in the oocyte the inhibition of IL-6 when treated with IL-10 in PV follicle establish the fact. Furthermore, results indicate the source of IL-6 and IL-10 in the ovary, is the granulosa cells for IL-6 and both theca and granulosa cells for IL-10 with secretion of IL-6 and IL-10 being induced by the additions of hCG and TNFα in the medium. There was also an IL-6-induced increase in abundance of receptors (IL-6 Rα and gp130) to which it binds indicating IL-6 autoregulates this population of receptors. There was also marked increase in IL-10 receptor IL-10R1 and IL-10R2 suggesting their involvement during the reproductive processes. Stat-3 activation ensured the involvement of IL-6 during the time of ovulation. Results from this study, for the first time, elucidate the reproductive functions of IL-6 in a teleost fish.Item Investigation of stress induced Tbx20 function in autophagy in heart with comparative analyses of extracellular matrix remodeling with multiple stress inductions in cultured cardiac cell lineChakraborty, SantanuTbx20, a T-box transcription factor, is known to be crucial for cardio genesis and murine models with Tbx20 knockout fail to survive beyond E10.5. Tbx20 mutations correspond with severe congenital heart defects including valvulogenesis and septal defects. 1–3 All T-box proteins have a DNA binding domain. The T-box domain of Tbx20 consists of 180 amino acid residues and Tbx20 has a binding affinity to T/2 site [(5’-…AGGTGTGA…-3’ over the consensus T-site 5’-…TCACACCT…-3’. 25 Tbx20 promotes cardiomyocyte proliferation via the Bmp2/pSmad1/5/8 and PI3K/AKT/GSK3β/β-catenin signaling pathways.4 Tbx20 has also been found to act as a cardio-protectant against oxidative stress and downregulation of Tbx20 has been linked to increased apoptosis in cultured rat cardiomyocytes.5 Further, the cardio-protective role of Tbx20 under ROS and hypoxic conditions in the H9c2 cell line was reported. 6 Tbx20 is known to interact with and induce other transcription factors like Nkx2.5 and Gata4 7,8 which are also important for cardiogenesis, maintaining cardiac homeostasis and promoting the expression of Troponin-I and myosin heavy chain protein. Autophagy is an evolutionarily conserved catabolic phenomenon that recycles cellular components to provide for bioenergetics and fuel for cellular survival under stress conditions. At the basal level, the goal of the autophagic machinery is to maintain cellular and organ homeostasis. This is achieved by providing catabolites like fatty acids and amino acids which in turn serve as substrates for many metabolic processes. The cargo (can be organelles, protein aggregates, lipids, cellular proteins) to be degraded is sent to lysosomes via autophagosomes whereby fusion of lysosomes with the latter forms autolysosomes and the cargo is thereafter degraded by lysosomal hydrolases. Autophagy can also be activated under stress conditions like nutrient scarcity/ caloric restriction, ROS (Reactive Oxygen Species) accumulation, ER (Endoplasmic Reticulum) stress, and mitochondrial damage where autophagy serves as a substrate recycling machinery remove protein aggregates and provides much-needed ATP for the survival of cells. 9–11Autophagy has been known to be a critical factor in the survival of neonates postpartum wherein it was found that Atg5 knockout mice models failed to survive after birth. Furthermore, in mice that survived the brief period of nutrient deprivation postpartum (which is the usual scenario), massive upregulation of cardiac autophagy was observed giving away the importance of autophagy in pro-survival while also bringing cardiac autophagy to the centre.12 Impaired and altered autophagy has been an underlying cause of cardiac diseases like AMI (acute myocardial infarction), Ischemic heart disease (IHD) and cardiomyopathy. A similar role of autophagy has been found in acute myocardial infarction wherein inhibition of autophagy enlarges the infarct zone and decreases the ATP content of cardiomyocytes and there have been theories that augmenting autophagy would be a therapeutic approach in restoring the cellular integrity and cardiac functioning in these case13–17 Aging is perhaps one of the greatest risk factors responsible for failing hearts. In fact, aged individuals with no underlying cardiac condition show poor cardiac functionality, diastolic function and left ventricular dilatation. 18–20Accumulation of protein aggregates, misfolded proteins, a poor balance between ROS and anti-oxidants, mitochondrial derangements, attenuated expression of Sirtuins (a class of NAD+ dependent deacetylating enzymes) especially Sirtuin 1, 3 (Sirt 1,3), GSk-3 contribute to cardiac aging.21–23 As such, impaired and poor levels of autophagy are prevalent in aging hearts while apoptotic levels are on a surge. Augmenting autophagy by either calorific restriction or Rapamycin (Rap) administration has shown improvement in cardiac functioning and improved life longevity.24–26 Here in this study for the first time, we demonstrate the role of Tbx20 as a potential candidate to induce anti-senescence-like characteristics in the aging mice population. Autophagy induced expression of Tbx20 activates GSK-3 and transcription factors Nkx2.5, Gata4 and Sirt1 after subjection to starvation (Strv) and rapamycin (Rap) treatment in both in-vivo (BALB/c mice) and in-vitro (H9c2 cell line) model systems. The upregulation of Nkx2.5 and Gata4 following autophagy induction is indicative of progression towards progenitor like cardiomyocyte characteristics, while activation of Sirt1 and GSK3 suggests an anti-aging/ senescence since Sirtuin1 is closely linked with aging, is known to be a mediator of caloric restriction and Sirt1 transgenic mice prevent early mortality. With pre-existing knowledge of the expression of Sirt1 and GSK-3 under autophagy conditions along with the cardioprotective roles they play, these two were chosen as possible candidates that could interact with Tbx20. Further, Tbx20 loss of function (LOF) assay in the H9c2 cell line validated Tbx20-dependent expression of Sirt1, GSK-3, Nkx2.5 and Gata4. On the other hand, ECM remodeling in heart or cardiac remodeling remains an important factor in the pathophysiology of cardiovascular diseases.27,28 Collagen-I forms the major component of the matrix interstitium of the myocardium in addition to Collagen-III, fibronectin, proteoglycans, tissue inhibitors of matrix metalloproteinases (TIMPs) and matrix metalloproteinases (MMPs). The three stages of cardiac remodeling following cardiac injury are inflammatory, proliferative and maturation phases leading to a mature scar formation.29 The preliminary stages of ECM remodeling are necessary as it prevents rupture of the ventricular wall, however, exacerbated ECM remodeling leads to progressive fibrosis in the heart and cardiac malfunctioning.30,31 The MMPs (zinc-dependent proteases) are involved in the turnover of matrix proteins like Collagen.32 Adamts4, a member of Adamts family is an important MMP. Adamts4, also is a disintegrin with thrombospondin like motifs.33,34 The mode of action of Adamts4 is by binding to ECM proteins and thereafter cleaving ECM proteoglycans like aagrecan, versican, brevican in addition to regulating Collagen turnover.35,36 Adamts4 modulates the pathophysiology of osteoarthritis through degradation of matrix proteoglycans and eventually lead to cartilage degradation which manifests as degenerative osteoarthritis.37,38 Besides osteoarthritis, Adamts4, has also been linked with cancer and angiogenesis where its role remains controversial. Some studies report it to be an indicator of early-stage cancer like in cases of colorectal cancer, others findings suggest that its mutated and truncated fragments may suppress tumour growth through inhibition of angiogenesis. 39,40 However, the involvement of Adamts4 in cardiac remodeling is relatively less known. Only a few studies have shown the involvement of Adamts4 in atherosclerotic plaque development.41 and recent studies have shown elevated expression of both Adamts4 and Adamts1 in patients with acute aortic dissection and coronary artery disease.42,43 To decipher the molecular cascade of Adamts4 induction and associated signaling pathway, cultured H9c2 cells were used for in vitro experiments. Adamts4 expression was induced in H9c2 cells following hypoxia (Hyp) and ROS and Hyperglycaemic stress inductions. Additionally, Adamts4 expression was manipulated by siRNA-mediated loss of function and TGF- inhibitor studies with SB431542/ALKI treatment in-vitro to evaluate the hierarchy and dependency on TGF- signaling. TGF- is a known marker for inflammatory and fibrotic responses following pathological stress like Myocardial Infarction, ischemia and reperfusion (I/R) injury.44–48 Ultimately, ADAMTS4 expression was also assessed in patients with cardiac diseases namely Dilated Cardiomyopathy (DCM) and MI. Overall, this study focusses on the role of Tbx20 under stress conditions and ECM remodeling.Item Characterization of Aluminum Stress Tolerance in Mung Bean for Crop ImprovementGanesan, M.Under acidic soil and aluminum stress conditions, the crop plants are facing several growth defects. Particularly significant decrease in root growth, nutrient uptake and low yield are the very common problems. Besides, several organic acid transporters are involved in Al sensing, transport and detoxification mechanisms. In this study, Al stress tolerance of mungbean plants was studied under different Al stress conditions. The results showed that the mungbean plants are severely affected by Al stress and released significant amount of malate in hydroponics media when compared with control plants. Based on this study and expression analysis of Al stress responsive genes, further, we developed ALMT1 overexpressors and ALMT1-RNAi transgenic plants of mungbean to analyze the acid soil tolerance. Later, these transgenic mungbean plants were challenged with different Al concentrations to check their stress responses. The ALMT1-RNAi lines showed almost no root growth variations in hydroponics media when compared to WT plants under normal growth conditions but displayed significant decrease in root length on exposure to Aluminum. Further, when AtALMT1 was overexpressed, even in absence of Aluminum stress, there was approximately 12% increase in length of primary roots when compared with WT. Malate efflux was almost doubled in the AtALMT1 overexpressed plant lines whereas KD lines showed around 36% drop in malate efflux under Al stress conditions. Therefore, based on these observations, we concluded that VrALMT1 has a significant role on Aluminum stress tolerance responses in mungbean plants.Item Characterization of the Bambusa tulda Roxb inflorescences and flowers at the morphological anatomical and genetic levels to understand floral organ developments and differentiation in bambooDas, MalayBamboos belong to the monocotyledonous plant family Poaceae and subfamily Bambusoideae. Bamboos represent an extreme example of perennialism, where the reproductive phase begins after completion of an extended vegetative phase, which may vary across species. Other than delayed flowering time, existence of two different types of inflorescences, genetics of floral development and nature of pollen compatibility make bamboo unique in comparison to other grasses. The main aim of this study was to understand the floral organ development and pollination mechanism in Bambusa tulda. In this study, the relative abundance of two different types of inflorescence in an entire flowering cycle were analysed and rate of seed setting was compared. One potential limitation to perform gene expression analyses on Bambusa members was the absence of suitable reference genes to normalize expression data. In this study, reference genes were identified, which were stable across species, organs and developmental stages. In order to understand the molecular mechanism that regulates flower development, the floral meristem identity genes MADS14, MADS15 and MADS18 were sequenced from B. tulda and their expression pattern was analyzed across different vegetative and reproductive tissues. In order to understand the genetics of pollen compatibility in bamboo, in vivo pollination experiments were performed. The finding indicated that B. tulda is primarily a cross pollinated species. In order to further understand the molecular mechanism regulating genetic compatibility in bamboo, selected members of RNase T2 and Fbox gene families were studied. Overall, the findings of this study will be useful to understand the morphological, ecological and molecular basis of flower development and genetic compatibility in bamboos.Item Screening of some phytochemicals and bioactive properties of selected naturally grown and micropropagated medicinal plants of the Apocynaceae familyRay, PujaBackground of the research: Medicinal plants, their identification, preservation and phytochemical profiling have become extremely important due to excessive demand of plant derived bioactive secondary metabolites as natural products, which have potentiated present day herbal drug, pharmaceuticals and nutraceuticals based industries in an unprecedented manner. Medicinal plants are marketed for their therapeutic effect but those particular plants, where root part is more valuable than the other parts, have higher threat of eradication from the wild due to overexploitation. Under in-vitro culture system application of elicitor molecule reportedly increases total root biomass and content of secondary metabolites. In West Bengal, there is a gap in medicinal plant research especially in the southern part. So, after mindful consideration, three high-value, ethno-medicinally important medicinal plants have been selected from the Apocynaceae family, namely, Hemidesmus indicus, Tylophora indica and Cryptolepis buchanani, which, i. are marketed for the root part; ii. are found mainly in the southern plain of West Bengal; iv. have significant therapeutic efficacy. Application of micropropagation, must be accompanied with phytochemical screening (crucial for quality control and selection of elite chemotype) as well as pharmacological studies. Aim of the study: Establishment of fast, effective and innovative micro-propagation protocol, for selected medicinal plants, which can aid in their conservation, sustainable usage and could be useful for higher accumulation of plant biomass. Qualitative and quantitative assay of phytochemicals and marker compounds of selected medicinal plants as well as the comparative assessment, between wild and invitro counterparts, for the selection of elite chemotype. Screening of selected pharmacological activities with solvent extract/powder/fraction obtained from mother plant and regenerated plantlets to estimate therapeutic and commercial value of in-vitro culture of selected medicinal plants. Materials and methods: PGR plus elicitor fortified, MS media based micropropagation protocol of these medicinal plants was established where the regenerated plantlets were exposed to in-planta elicitation. The goal was to check its role on biomass generation and marker compound accumulation. Assessment of clonal fidelity was done; evaluation of various parameters and establishment of experimental model to estimate the role of different variables under in-vitro culture was performed. The mother plant (wild) and regenerated plantlets were tested cum compared for phytochemical content (TPC, TFC, TTC); photosynthetic pigment content; anti-oxidant efficacy (DPPH, FRAP, SOD, CAT, APX assay); anti-bacterial property and pancreatic lipase inhibitory activity. Moreover, quantification of marker compounds done via simple, robust and standardized HPTLC technique. Results: As root is the main part for the accumulation of marker compounds in all these three plants, the impact of different variables on the root length has been analyzed. MS- BAP (1.5 mg/l) combo has produced the highest (6.7) ‘number of shoots / explant’ and the ‘average shoot length’ is 11.7 cm in case of H. indicus. The values of these two parameters are 4.1 and 9.2 cm, respectively as observed in T. indica. In case of C. buchanani, Kin (1mg/l) has generated maximum shoot length (6.8 cm) despite of a trend of slow growth. In all these plants, IBA 1.5 mg/l have promoted rooting phenomenon more than the other combinations of auxin. Profuse base callus formation and increase in fresh weight of nodular meristemoids have been noted in T. indica which may be connected with lower multiplication rate in this plant. Methyl jasmonate (50 μM) based elicitation of healthy microshoots has yielded promising result in T. indica and H. indicus but this phenomenon is absent in C. buchanani. ISSR marker based genetic fidelity assessment has been done in support of the monomorphic plant production trend in tissue culture. Phytochemical screening has revealed the TPC, TFC, TTC, PPC content in mother plants and when the values were compared with the in-vitro ones, significant content wise compatibility has been observed in other two plants except C. buchanani. The activities of antioxidant enzymes (SOD, CAT, APX), DPPH, FRAP assays plus pancreatic lipase inhibitory activity of all these plants have confirmed the assumption that in-vitro raised plants can be a sustainable option against the wild plants in terms of basic bioactivity and phytochemical content. This idea was further supported by the rapid, validated, and sensitive densitometric HPTLC based quantification of marker compounds. In H. indicus and T. indica the values of the markers (MBAld and tylophorine respectively) are noteworthy in elicitor treated root samples and similar with naturally grown root sample. In C. buchanani, HPTLC was applied to assay the content of cryptolepine in leaf tissues of wild and micropropagated ones. The naturally harvested samples of C. buchanani have yielded better result in all phytochemical and pharmacological screening. In case of the anti-bacterial activity, the marker compounds have demonstrated significant result. Conclusions: The plants which have been selected for the present study; have traditional acceptance and commercial application. Considering their pharmaco-therapeutic importance plus overexploitation scenario the present work has recommended a fast and effective micropropagation technique, Multifaceted screening of all three medicinal plants; which have been collected from the southern part of West Bengal, is reported in the present work for the very first time. The results have also highlighted the prospective application of in-vitro micropropagation technique as a sustainable cum potential remedy against overexploitation of valuable medicinal plants.Item Investigating the relationship between Pro Apoptotic Anti Apoptotic and Proliferation pathways mediated by TNF Related Apoptosis Inducing Ligand TRAILPal, RanjanaTriple Negative Breast Cancer (TNBC) being devoid of the hormonal receptors manifests a difficult challenge for different therapeutic approaches. As TRAIL (TNF Related Apoptosis Inducing Ligand) is known for its ability to cause damage specifically to the tumor cells. Whole transcriptome analysis of MDA-MB-231 cell line treated with rhTRAIL showed upregulation of more than 1.5fold in nine genes from the complement pathway. Kaplan-Meiers plotter showed Complement component 4B (CFB) to be positively corelated with relapse free survival in breast cancer patients. CFB was also observed to be co-related and co-expressed with TRAIL in TNBC patients. Because of the heterogenicity of breast tumor population, some cells are inherently resistant to TRAIL induced apoptosis. Via microarray analysis of the selected resistant cells, we observed CDH1 to be downregulated in the resistant cell population in comparison to the sensitive cells. Upregulation of CDH1 sensitized the resistant cells towards rhTRAIL mediated cell death. Another commonly used approach to increase the effectiveness of the TRAIL treatment is through combination therapy. Theophylline has a cytotoxic effect on the MDA-MB-231 cell line. It increased ROS production causing DNA damage and lipid peroxidation. We further observed theophylline to increase the level of TNFR1, thereby activating the caspase mediated apoptotic pathway. Moreover, rhTRAIL in combination with theophylline caused increased cell death in comparison to rhTRAIL or theophylline alone. Combination treatment increased the levels of DR5 in the rhTRAIL and theophylline treated cells. Therefore, we can conclude that CFB and CDH1 can be used as biomarkers for TRAIL therapy in breast cancer. Furthermore, rhTRAIL in combination with theophylline could be a possible alternative for breast cancer therapy. Keywords: rhTRAIL, CFB, CDH1, DR4, DR5 and theophyllineItem Apoptosis regulators as targets for induction of apoptosis of Imatinib resistant chronic myeloid leukemia cellsBiswas, NabenduApoptosis is a regulated cell death characterized by cell shrinkage, nuclear condensation, DNA fragmentation, membrane blebbing. There are several apoptosis regulators eg: BCL2, Bcl-xL, BAX, Survivin, FLIP, XIAP, cIAP etc. Targeting these apoptosis regulators may be a viable strategy for the treatment of cancer because one of the hallmarks of cancer is the deregulation of apoptosis. In our first study we tried to induce cell death in Imatinib-resistant chronic myelogenous Leukemia cell line K562, by using TRAIL, a well-studied anti-cancer agent. Normally these cells are also resistant to TRAIL. We used Hydroxychavicol, a Piper betel leaf derived polyphenol, to make this Imatinib- resistant K562 cells sensitive to TRAIL. In imatinib resistant K562 cells, XIAP, FLIP have emerged as targets by hydroxychavicol to sensitize the cells to TRAIL mediated apoptosis. Reactive Oxygen Species, particularly H2O2 has been shown to be a key player for this TRAIL sensitization by Hydroxychavicol. We found that ROS decreased XIAP, FLIP in imatinib sensitive K562(S) and imatinib resistant K562(R) both. These XIAP and cFLIP downregulation abrogated their inhibitory effect on Caspase activation and removed its break from extrinsic apoptotic pathway activation by TRAIL and this leads to apoptosis of Imatinib-resistant K562 cells and imatinib sensitive K562 cells. In Imatinibresistant K562 cells, FLIP and XIAP were differentially regulated by JNK and ERK respectively. Akt phosphorylation was decreased by ROS-activated ERK. Dephosphorylation of Akt inhibited its binding to XIAP and that lead to the destabilization of XIAP. On the other hand, ROS-activated JNK increased the expression of an ubiquitin ligase ITCH which degraded FLIP by binding to it and ubiquitination. However, interestingly, when we checked these finding on K562(S) cells, some of the findings were different. In K562(S) cells, ROS degrades XIAP, FLIP by lysosomal degradation pathway. Moreover, JNK alone instead of JNK and ERK played important role in this XIAP and FLIP downregulation. Thus, our findings suggest anti-apoptotic proteins XIAP and FLIP as a viable therapeutic target for Imatinib-resistant CML. We have also identified a novel ROS mediated regulatory pathway of these two proteins which may be further explored for therapeutic targets.Item A Study of Antibacterial and Anti-Inflammatory Activity of Zinc Oxide Nanoparticles (ZnONPs) on Multiple Antibiotic-Resistant Staphylococcus Aureus Induced Inflammatory Rat ModelSikdar, MausumiConventional treatment strategies involving antibiotics are gaining accelerated challenges as a result of increasing antibiotic resistance by pathogenic microorganisms. A significant quantity of therapeutic research had been focused on implementing green synthesized nanoparticles. In this study, the green synthesis method has been used to prepare ZnONPs from leaf extract of coriander. The green synthesized and chemically synthesized commercially available ZnONPs showed almost no variation concerning their size and morphology when characterized by methods like XRD, DLS, etc. Comparison of antibacterial potential among both types of ZnONPs, used against strains of (Control and Clinical) reveals, lower MIC and MBC of green ZnONPs were required to generate the same quality of bactericidal effect as achieved by using the commercial one. This signifies that, apart from easy synthesis procedure, lower doses are enough to generate the desired anti-bacterial efficacy. After inducing septic arthritis by clinical strain (KC-02) of S. aureus, both ZnONPs (chemical and green) were capable of lowering the increased serum level of inflammatory markers, without producing the measurable amount of serum oxidative stress. The combination of ZnONPs (both chemical and green) and antibiotics shows excellent antibacterial and anti-inflammatory potential. The part of this study involving the in-vivo model indicates that both the ZnONPs when used in the mentioned concentration alone and also in combination with an antibiotic, are incapable of precipitating histological changes in selected organs like the liver, kidney, spleen, and adrenal gland. Therefore, the use of ZnONPs, a preferably green one for treating inflammatory diseases like septic arthritis, could be a better choice over conventional antibiotic therapy.Item Comparative Analysis of Eukaryotic Homo sapiens and Oryza sativa indica Class IV SirtuinsDey, SanghamitraSirtuins are a class of proteins biologically acting as epigenetic modulators. They are generally found to be involved in regulating the essential cellular processes like metabolism, aging and genome stability. In our studies we have investigated the class IV sirtuins to explore the mechanistic and regulatory aspect of this protein family. To understand the role of class IV sirtuins better we took representatives from both human and plant. Human class IV sirtuins HsSIRT6 and HsSIRT7 are nuclear and nucleolar proteins, respectively whereas OsSRT1 is a nuclear protein. Using HsSIRT6 as a control/model, we investigated the biochemical and epigenetic activities of HsSIRT7 and OsSRT1. From our studies, we found that N and C terminal region of these proteins have important role in their enzymatic activities and substrate recognition. N-terminal region in HsSIRT7 is associated with protein-protein interactions and C-terminus is often associated with subcellular localization. In case of OsSRT1, the extended C-terminal region plays important role in substrate recognition and catalysis. Sirtuins in general have a unique substrate specificity. There were available reports of H3K9Ac deacetylation by OsSRT1 and H3K18Ac deacetylation by HsSIRT7. Our studies shed light on its dual enzyme capability with preference for mono ADP ribosylation (mono ADPr) over deacetylation. Just like its plant counterpart, a comparison of these dual activities suggests HsSIRT7's preference for the mono ADPr transfer over its deacetylation of H3K18Ac. Several new targets for both the deacetylation and ADP ribosylation were detected. Class IV sirtuins can specifically transfer the single ADP ribose group on its substrates in an enzymatic manner. So, this study is the first one to report the ADP ribosylation activity in HsSIRT7 and OsSRT1, which were previously reported as only deacetylases. This mono ADPr effect is not well known in plants, more so for deacetylases. The products of this reaction (NAM and ADP ribose) have immense negative effect on these enzymes suggesting a tighter regulation. Under various ranges of abiotic stress conditions in rice plants, we could link this ADPr activity to the DNA repair pathway by activating the enzyme PARP1. The histone specific deacetylation is also related with OsSRT1 upregulation under these stress situations. Metal toxicity in plants also influences these enzyme activities. Mono ADP ribosylation in cells is often linked to different metabolic disease conditions. This kind of modification of transcription factors, p53 and ELK4 by HsSIRT7 may play a key role in maintaining the tumor phenotype. Thus, HsSIRT7 becomes an important therapeutic hotspot for drug designing to counter several disease conditions. Screening of several chemical compounds with HsSIRT7 active site has been carried out in this study.Item Studies on the Protection of Arsenic Induced Reproductive Disorders in Adult Male Wistar Rats by Formulated High Protein DietMukhopadhyay, Prabir KumarArsenic toxicity is a major worldwide health problem and has been associated with several reproductive system disorders. The study was designed to investigate the protective role of casein–pea-enriched protein diet /formulated high protein diet (FHPD) on arsenic-mediated testicular and spermatozoal anomalies in adult Wistar rats. The rats (120±10gm) were randomly divided into three groups: Gr I (control) received the normal diet; the Gr II (treated) was given arsenic orally for 30 consecutive days as arsenic trioxide (3mg/kg/rat/day) where as Gr III (supplemented) was given isocaloric FHPD along with arsenic of same dose. Same animal model was used for the fulfilment of all the objectives. The results revealed significant reduction in weight of testis along with other accessory reproductive organs. Structural and functional alterations of testes, cauda epididymis and caudal spermatozoa were observed. Reduction of steroidogenesis, gonadotrophins and spermatogenesis were also noted. Increased oxidative stress resulted redox imbalance in testes, cauda epididymis and spermatozoa causing successive DNA damages. Apoptosis was initiated in testes as expression of apoptotic markers like Bax, Bcl-2, caspase 9 and caspase 3 were seen to be altered. Spermatozoal apoptosis was also noted by Annexin V-Pi staining. Arsenic deposition was also noted in testicular tissues. All these anomalies were attenuated when FHPD supplementation was given to arsenic-gavaged rats. Casein–pea-enriched protein diet/ FHPD mitigated the adverse effects of arsenic and helped in sustaining the normal reproductive functions.Item Crosstalk between Proteasomal and Lysosomal Protein Degradation Pathway in EBV-Induced B-cell LymphomasSaha, AbhikEpstein-Barr virus (EBV) nuclear oncoprotein EBNA3C plays an important role during B-cell transformation and subsequent development of several B-cell lymphomas specifically in those who are from immuno-compromised background. EBNA3C manipulates several important cellular pathways including ubiquitin-proteasome machinery and deregulate multiple cellular oncoproteins and tumor suppressor proteins. Studies have revealed that EBNA3C is ubiquitinated at its N-terminal domain and can interact with 20S proteasome machinery. However, In vitro, the viral protein is extremely stable in EBV transformed growing B-lymphocytes. EBNA3C can also bypass autophagy-lysosomal mediated protein degradation and subsequent antigen presentation for T-cell recognition. Moreover, recently, our group demonstrated that in response to metabolic stress, EBNA3C elevates the basal level of autophagy through epigenetic alternation and transcriptional activation of several autophagy related genes (ATGs). This also serves as a prerequisite for B-cell survival under growth limiting conditions. The crosstalk between EBNA3C mediated proteasomal and autophagy-lysosomal machinery further prompted us to investigate the underlying proteolytic mechanism governing EBNA3C’s turn-over. We demonstrate that proteasomal inhibition accelerates EBNA3C degradation both in EBV transformed B-lymphocytes and ectopic-expression systems. Interestingly, in presence of proteasomal inhibitors, two EBNA3 family oncoproteins–EBNA3A and EBNA3C were degraded, but not the viral tumor suppressor protein EBNA3B. EBNA3C degradation induced by proteasomal inhibition is partially blocked when autophagy-lysosomal pathway is inhibited. In response to proteasomal inhibition, EBNA3C is predominantly K63-linked polyubiquitinated and colocalized with the autophagy-lysosomal fraction in the cytoplasm and participated within p62-LC3B complex, thus facilitating autophagy-mediated degradation. We further describe that the degradation signal is located at the first 50 residues of the N-terminal domain of EBNA3C. The colony formation ability of this important viral oncoprotein is also reduced when proteasome is blocked. In addition, proteasomal inhibition induces apoptotic cell death and accelerates transcriptional activation of both latent and lytic gene expression which further induces viral reactivation from EBV transformed B-lymphocytes. Overall, this study provides rationale to use proteasome inhibitors as potential therapeutic strategy against multiple EBV associated B-cell lymphomas.