Antifungal activity of violacein purified from a novel strain of Chromobacterium sp. NIIST (MTCC 5522)

Anju Sasidharan,Nishanth Kumar Sasidharan,Dileepkumar Bhaskaran Nair Saraswathy Amma,Radhakrishnan Kokkuvayil Vasu,Anupama Vijaya Nataraja,Krishnakumar Bhaskaran 한국미생물학회 2015 The journal of microbiology Vol.53 No.10

A novel strain of Chromobacterium sp. NIIST (MTCC 5522) producing high level of purple blue bioactive compound violacein was isolated from clay mine acidic sediment. During 24 h aerobic incubation in modified Luria Bertani medium, around 0.6 g crude violacein was produced per gram of dry weight biomass. An inexpensive method for preparing crystalline, pure violacein from crude pigment was developed (12.8 mg violacein/L) and the pure compound was characterized by different spectrometric methods. The violacein prepared was found effective against a number of plant and human pathogenic fungi and yeast species such as Cryptococcus gastricus, Trichophyton rubrum, Fusarium oxysporum, Rhizoctonia solani, Aspergillus flavus, Penicillium expansum, and Candida albicans. The best activity was recorded against Trichophyton rubrum (2 μg/ml), a human pathogen responsible for causing athlete’s foot infection. This is the first report of antifungal activity of purified violacein against pathogenic fungi and yeast.

Micro- and Macro-Level Factors Determining Financial Performance of UAE Insurance Companies

SASIDHARAN, Soumya,RANJITH, V.K.,PRABHURAM, Sunitha Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.12

The research aims to analyze the firm-specific and macroeconomic factors that affect insurance company's financial performance. The research explores the variables that influence the financial performance of the United Arab Emirates (UAE)' insurance companies. The analysis for determining financial performance considers the following variables: the firm's age, retention ratio, capital adequacy, underwriting risk/loss ratio, financial-leverage, reinsurance dependency, and macro-economic factors such as GDP per capita, inflation rate considered as independent factors. The return-on-asset (ROA) is the key measuring indicator; it is regarded as the dependent variable for financial performance measures. The research focuses on secondary information obtained from insurance companies' financial statements. The researcher targeted 18 insurance companies listed on the UAE stock exchanges for study purposes. The research examines the overall factors that influence the financial performance of an insurance company. For analysis of data, software package of social sciences (SPSS version 20) is used. The studies used correlation and multiple linear regression analysis to determine financial performance and their effects. The analysis suggests that there are important and constructive relationships between the size, capital adequacy, and reinsurance dependency, while loss ratio, retention ratio, and financial leverage indicate a major negative relationship. And there's no link between GDP per capita and inflation.

Vitamin C Facilitates Demethylation of the <i>Foxp3</i> Enhancer in a Tet-Dependent Manner

Sasidharan Nair, Varun,Song, Mi Hye,Oh, Kwon Ik American Association of Immunologists 2016 Journal of Immunology Vol. No.

<P>Demethylation of CpG motifs in the Foxp3 intronic element, conserved noncoding sequence 2 (CNS2), is indispensable for the stable expression of Foxp3 in regulatory T cells (Tregs). In this study, we found that vitamin C induces CNS2 demethylation in Tregs in a ten-eleven-translocation 2 (Tet2)-dependent manner. The CpG motifs of CNS2 in Tregs generated in vitro by TGF-beta (iTregs), which were methylated originally, became demethylated after vitamin C treatment. The conversion of 5-methylcytosin into 5-hydroxymethylcytosin was more efficient, and the methyl group from the CpG motifs of Foxp3 CNS2 was erased rapidly in iTregs treated with vitamin C. The effect of vitamin C disappeared in Tet2 2/2 iTregs. Furthermore, CNS2 in peripheral Tregs in vivo, which were demethylated originally, became methylated after treatment with a sodium-dependent vitamin C transporter inhibitor, sulfinpyrazone. Finally, CNS2 demethylation in thymic Tregs was also impaired in Tet2 2/2 mice, but not in wild type mice, when they were treated with sulfinpyrazone. Collectively, vitamin C was required for the CNS2 demethylation mediated by Tet proteins, which was essential for Foxp3 expression. Our findings indicate that environmental factors, such as nutrients, could bring about changes in immune homeostasis through epigenetic mechanisms.</P>

Antioxidant and anticancer activity of 3,5-dihydroxy-4-isopropylstilbene produced by Bacillus sp. N strain isolated from entomopathogenic nematode

Sasidharan Nishanth Kumar,Bala Nambisan,B. S. Dileep Kumar,Nisha Girija Vasudevan,Chellapan Mohandas,Vino T. Cheriyan,Ruby John Anto 대한약학회 2021 Archives of Pharmacal Research Vol.44 No.9

3,5-Dihydroxy-4-isopropylstilbene is a naturalphytoalexin and was first identified as bacterial secondarymetabolites. The aim of this study is to investigate in vitroantioxidant and anticancer activity of 3,5-dihydroxy-4-isopropystilbene purified from the cell free culture filtrateof Bacillus sp. N strain associated with rhabditid entomopathogenicnematode. Antioxidant activity was evaluatedby five separate methods: free radical scavenging, reducingpower assay, chelating effects on ferrous ions, NBTsuperoxide radical scavenging assay and hydroxyl radicalscavenging activity. The stilbene recorded powerful antioxidantactivity at various antioxidant systems in vitro. Thesuperoxide radical scavenging (92.1 %) and hydroxylradical scavenging (83.4 %) activities of the stilbenes at100 lg/ml were higher than the butylated hydroxyanisole,the known antioxidant agent. Anticancer activity of stilbenewas tested against breast cancer (MDAM B-231),cervical cancer (HeLa), lung cancer (A 549), colon cancer (HTL 116) cell lines using MTT method. The induction ofapoptosis was studied by morphological analysis, apoptoticcell staining, caspase 3 activation assay and cell cycleanalysis using flow cytometry. Stilbene induced significantmorphological changes and DNA fragmentation associatedwith apoptosis in HeLa cells. Acridine orange/ethidiumbromide stained cells indicated apoptosis induction bystilbene. Up-regulation of caspase 3 activity was also foundin cells treated with stilbene. Flow cytometry analysisshowed an increase in the percentage of apoptotic cells insub G0 phase (2.4 % in control plates to 11.4 %in 25 lg/mlof stilbene) confirming the stilbene induced apoptosis. Theresults of the present study showed that stilbene demonstrateda strong antioxidant and anticancer effects. Thesesuggest that stilbene may be used as possible naturalantioxidant and anticancer agents to control various humandiseases.

Deactivation of Telomerase Enzyme and Telomere Destabilization by Natural Products: a Potential Target for Cancer Green Therapy

Sasidharan, Sreenivasan,Jothy, Subramanion L,Kavitha, Nowroji,Chen, Yeng,Kanwar, Jagat R Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.18

Caproate Production Enhanced by Caproiciproducens galactitolivorans through the Pathway Shift Using Hydrogen as an Electron Donor

Pranav SASIDHARAN,Hyunjin KIM,Okkyoung CHOI,Byoung-In SANG 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10

Chain elongation (CE) technology, biological conversion to medium chain carboxylic acids (MCCAs) from short chain organic compounds, has gained more attraction recently due to the production of value-added products from organic waste. In the CE process, it has always been a bottleneck that the low selectivity of MCCAs compared with short chain acetate and/or butyrate. In this study cell growth and metabolite composition of Caproiciproducens galactitolivorans cultivated under high hydrogen (H₂) partial pressure were compared to those obtained from the control. The supplement of hydrogen led to a significant improvement in the final metabolite production ratio (n-caproate/acetate [mol C/㏖ C]) compared to the control (from 1.90 to 2.78). Hydrogen enhanced the reducing power for n-caproate production by altering the electron flow from ferredoxin to NADH, resulting in reduced carbon flow towards acetate production. Cultivation of Caproiciproducens galactitolivorans using hydrogen as an electron donor could be considered as a feasible alternative to improve the n-caproate production.

Ramifi cations of Structural Deformations on Collapse Loads of Critically Cracked Pipe Bends Under In-Plane Bending and Internal Pressure

Sumesh Sasidharan,Veerappan Arunachalam,Shanmugam Subramaniam 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.1

Finite-element analysis based on elasticeperfectly plastic material was conducted to examine the influence of structural deformations on collapse loads of circumferential through-wall critically cracked 90˚ pipe bends undergoing in-plane closing bending and internal pressure. The critical crack is defined for a through-wall circumferential crack at the extrados with a subtended angle below which there is no weakening effect on collapse moment of elbows subjected to in-plane closing bending. Elliptical and semioval cross sections were postulated at the bend regions and compared. Twice-elastic-slope method was utilized to obtain the collapse loads. Structural deformations, namely, ovality and thinning, were each varied from 0% to 20% in steps of 5% and the normalized internal pressure was varied from 0.2 to 0.6. Results indicate that elliptic cross sections were suitable for pipe ratios 5 and 10, whereas for pipe ratio 20, semioval cross sections gave satisfactory solutions. The effect of ovality on collapse loads is significant, although it cancelled out at a certain value of applied internal pressure. Thinning had a negligible effect on collapse loads of bends with crack geometries considered.

Shaping Methane Emission Patterns: Megasphaera hexanoica-driven Rumen Microbiome Engineering

Pranav SASIDHARAN NAIR,Byoung-In SANG 한국생물공학회 2023 한국생물공학회 학술대회 Vol.2023 No.10

DNA Demethylation of the Foxp3 Enhancer Is Maintained through Modulation of Ten-Eleven-Translocation and DNA Methyltransferases

Nair, Varun Sasidharan,Song, Mi Hye,Ko, Myunggon,Oh, Kwon Ik Korean Society for Molecular and Cellular Biology 2016 Molecules and cells Vol.39 No.12

Stable expression of Foxp3 is ensured by demethylation of CpG motifs in the Foxp3 intronic element, the conserved non-coding sequence 2 (CNS2), which persists throughout the lifespan of regulatory T cells (Tregs). However, little is known about the mechanisms on how CNS2 demethylation is sustained. In this study, we found that Ten-Eleven-Translocation (Tet) DNA dioxygenase protects the CpG motifs of CNS2 from re-methylation by DNA methyltransferases (Dnmts) and prevents Tregs from losing Foxp3 expression under inflammatory conditions. Upon stimulation of Tregs by interleukin-6 (IL6), Dnmt1 was recruited to CNS2 and induced methylation, which was inhibited by Tet2 recruited by IL2. Tet2 prevented CNS2 re-methylation by not only the occupancy of the CNS2 locus but also by its enzymatic activity. These results show that the CNS2 methylation status is dynamically regulated by a balance between Tets and Dnmts which influences the expression of Foxp3 in Tregs.

Validation of Combs prognostic scoring system in Indian recurrent glioma patients treated with re-radiation

Debnarayan Dutta(Debnarayan Dutta ),Meenu Jose(Meenu Jose ),Sruthi Kalavagunta(Sruthi Kalavagunta ),Ajay Sasidharan(Ajay Sasidharan ),Haridas Nair(Haridas Nair ),Annex H. Edappattu(Annex H. Edappattu 대한방사선종양학회 2024 Radiation Oncology Journal Vol.42 No.1

Purpose: Retrospective audit of recurrent glioma patients treated by different fractionation schedules and to validate the modified Combs prognostic score in Indian patient cohort. Materials and Methods: Between Jan 2009 and June 2022, 66 recurrent gliomas patients treated with standard adjuvant treatment—radiation (RT) ± temozolomide (chemotherapy)—and re-treated with RT (± chemotherapy) were categorized as per modified Combs prognostic criteria and outcomes were compared. Results: Sixty-six patients with recurrent gliomas who received reirradiation (re-RT) were audited—53% males; 61% Karnofsky performance status (KPS) ≥80 at time of re-RT; median age 41.5 years (range, 6 to 70 years); 67% <50 years; primary histology low-grade glioma in 33% ; grade III 27%, grade IV 40%; initial median dose of 60 Gy equivalent dose in 2 Gy fractions (EQD2); maximum safe resection at recurrence 41%; mean and median follow-up 78 ± 51 months and 66 months. Mean time interval between RT was 46.4 ± 39 months. Mean planning target volume (PTV) volume in conventional RT (Conv-RT), hypofractionated RT (Hypo-RT), and ultra-hypofractionated RT (UF-RT) was 226.1 ± 140.7 mL, 162.8 ± 123.3 mL, and 143.3 ± 145.8 mL. Mean dose for Conv-RT, Hypo-RT, and UF-RT was 50 Gy (range, 40 to 60), 31 Gy (range, 20 to 40), and 20 Gy (range, 10 to 30). Mean overall survival (OS) in Conv-RT, Hypo-RT, and UF-RT cohort was 18.8 months (range, 2.4 to 76.8); 6.6 months (range, 2 to 17.4), and 13.9 months (range, 3 to 131.9). Median OS as per Combs criteria were 16.6 months (Group a), 24.6 months (Group b), 4.6 months (Group c), and 3 months (Group d). Significant survival benefit was with good KPS score (KPS >80 vs. <80; 20.46 vs. 5.25 months; p < 0.001), patients receiving salvage chemotherapy (20.46 vs. 6.96 months; p = 0.001), and patients received re-RT biological equivalent dose (BED3) >80 Gy (16.62 vs. 5.48 months; p = 0.03). Median overall survival (OS) in our patient cohort and Combs cohort in Group a was 16.6 and 19.5 months; Group b was 24.6 and 11.3 months; Group c was 4.7 and 8.1 months, and Group d was 2 and 5.5 months, respectively. Six months survival in our patient cohort and Combs cohort in Groups a, b, c, d were 100%, 92%, 34%, 17% and 94%, 79%, 70%, 41%, respectively. Twelve months survival in our patient cohort and Combs cohort in Groups a, b, c, d were 88%, 74%, 22%, 0% and 88%, 47%, 22%, 7%, respectively. Conclusion: Modified Combs prognostic factors predicts OS and is applicable in Indian subcontinent patient population.