Department of Animal Biology

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    11-Hydroperoxyeicosatetraenoic acid is the major dioxygenation product of lipoxygenase isolated from hairy root cultures of Solanum tuberosum
    ( 1992-12-30) Ramakrishna Reddy, G. ; Reddanna, Pallu ; Channa Reddy, C. ; Curtis, Wayne R.
    The profile of primary dioxygenation products of arachidonic acid catalyzed by lipoxygenase isolated from hairy root cultures of Solanum tuberosum treated with a fungal elicitor was compared to that obtained for the enzyme from potato tubers. 11-Hydroperoxyeicosatetraenoic acid (11-HPETE) was the most abundant dioxygenation product formed followed by 8- and 5-HPETEs in the decreasing order of abundance. In contrast, 5-HPETE is the predominant oxidation product of lipoxygenase from potato tubers. Differences in the defense requirements of storage tuber as compared to roots may be the basis of the differences in regiospecificity demonstrated in this work. © 1992.
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    15(S)-HETE-induced angiogenesis in adipose tissue is mediated through activation of PI3K/Akt/mTOR signaling pathway
    ( 2013-12-01) Soumya, Sasikumar J. ; Binu, Sheela ; Helen, Antony ; Reddanna, Pallu ; Sudhakaran, Perumana R.
    Chronic low-grade inflammation underlies obesity and associated metabolic dysfunctions. Lipoxygenase pathways are activated in adipose tissue during obese conditions. Since adipogenesis is associated with angiogenesis, the present study was designed to examine the role of 15-lipoxygenase metabolite, 15(S)-hydroxyeicosatetraenoic acid [15(S)-HETE] on angiogenesis in adipose tissue. Results showed that 15(S)-HETE induced sprouting in fat pad stromovascular tissues, induced morphological changes relevant to angiogenesis in endothelial cells derived from adipose tissue, upregulated the production of CD31, upregulated the gene level expression and production of vascular endothelial growth factor (VEGF), indicating the pro-angiogenic effect of 15(S)-HETE. LY294002, an inhibitor of PI3K-Akt pathway, and rapamycin, inhibitor of mammalian target of rapamycin (mTOR), significantly reversed the effect of 15(S)-HETE. 15(S)-HETE also induced activation of Akt and mTOR. These observations suggest that 15(S)-HETE stimulates angiogenesis in adipose tissue through activation of PI3K/Akt/mTOR signaling. © 2013 Published by NRC Research Press.
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    15-Lipoxygenase metabolites of α-linolenic acid, [13-(S)-HPOTrE and 13-(S)-HOTrE], mediate anti-inflammatory effects by inactivating NLRP3 inflammasome
    ( 2016-08-18) Kumar, Naresh ; Gupta, Geetika ; Anilkumar, Kotha ; Fatima, Naireen ; Karnati, Roy ; Reddy, Gorla Venkateswara ; Giri, Priyanka Voori ; Reddanna, Pallu
    The ratio of ω-6 to ω-3 polyunsaturated fatty acids (PUFAs) appears to be critical in the regulation of various pathophysiological processes and to maintain cellular homeostasis. While a high proportion of dietary intake of ω-6 PUFAs is associated with various inflammatory disorders, higher intake of ω-3 PUFAs is known to offer protection. It is now well established that beneficial effects of ω-3 PUFAs are mediated in part by their oxygenated metabolites mainly via the lipoxygenase (LOX) and cyclooxygenase (COX) pathways. However, the down-stream signaling pathways that are involved in these anti-inflammatory effects of ω-3 PUFAs have not been elucidated. The present study evaluates the effects of 15-LOX metabolites of α-linolenic acid (ALA, ω-3 PUFA) on lipopolysaccharide (LPS) induced inflammation in RAW 264.7 cells and peritoneal macrophages. Further, the effect of these metabolites on the survival of BALB/c mice in LPS mediated septic shock and also polymicrobial sepsis in Cecal Ligation and Puncture (CLP) mouse model was studied. These studies reveal the anti-inflammatory effects of 13-(S)-hydroperoxyoctadecatrienoic acid [13-(S)-HPOTrE] and 13-(S)-hydroxyoctadecatrienoic acid [13-(S)-HOTrE] by inactivating NLRP3 inflammasome complex through the PPAR-γ pathway. Additionally, both metabolites also deactivated autophagy and induced apoptosis. In mediating all these effects 13-(S)-HPOTrE was more potent than 13-(S)-HOTrE.
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    15-LOX metabolites and angiogenesis: Angiostatic effect of 15(s)-hpete involves induction of apoptosis in adipose endothelial cells
    ( 2014-01-01) Soumya, Sasikumar J. ; Binu, Sheela ; Helen, Antony ; Reddanna, Pallu ; Sudhakaran, Perumana R.
    Inflammation is critical in the dysregulated growth of adipose tissue and associated vascular dysfunctions. 15-Lipoxygenase metabolites, important mediators of inflammation in adipose tissue during obese conditions, may contribute to codependence of inflammation and angiogenesis in adipose tissue. We have already reported the pro-angiogenic effect of 15(S)-HETE in adipose tissue. The present study was designed to understand the effect of 15(S)-HPETE, precursor of 15(S)-HETE, on angiogenesis in adipose tissue. Results showed that 15(S)-HPETE exerts an anti-angiogenic effect in adipose tissue. This was evidenced fromdecreased endothelial sprouting in adipose tissue explants, inhibition of angiogenic phenotype in adipose endothelial cells, decreased production of CD31 and VEGF in endothelial cells treated with 15(S)-HPETE. Further studies to examine the molecular mechanism of anti-angiogenic effect of 15(S)-HPETE showed that it inhibited cell survival signaling molecule Akt and anti-apoptotic Bcl-2 and also activated caspase-3 in adipose endothelial cells. These observations indicate that 15(S)-HPETE exerts its angiostatic effect in adipose tissue by inducing apoptosis of endothelial cells.
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    20-Hydroxyecdysone regulation of H-fibroin gene in the stored grain pest Corcyra cephalonica, during the last instar larval development
    ( 2011-01-01) Chaitanya, R. K. ; Sridevi, P. ; Senthilkumaran, B. ; Dutta Gupta, Aparna
    20-Hydroxyecdysone (20E) controls molting, metamorphosis and reproduction of insects. It binds to a heterodimeric complex of ecdysone receptor (EcR) and ultraspiracle (USP), and regulates the transcription of genes containing ecdysone response elements (EcREs). However, the 20E regulation of silk fibroin genes is largely unexplored. In most lepidopteran larvae, the silk fibroin primarily consists of a large protein, heavy chain fibroin (H-fibroin) that is associated with two small proteins, L-chain fibroin and P25. In the present study, we demonstrate that 20E regulates the expression of H-fibroin gene in Corcyra cephalonica, in a dose-dependent manner during the last instar larval development. Semi-quantitative and real-time PCR studies reveal that physiological doses of 20E do not alter the normal expression, whereas higher doses cause a significant decline in the expression. Luciferase activity assays and gel shift experiments further confirm the presence of a functional EcRE in the upstream region of H-fibroin which regulates the ecdysteroid dependent transcriptional activity of fibroin gene through EcR. In vitro treatment with 20E mimicking insecticides, RH-5849 and RH-5992 decreases the expression of H-fibroin in isolated salivary glands. Insects fed with similar concentrations of these insecticides, metamorphose abnormally. Differences are also observed in the ultrastructure of the silk fibers of control and insecticide fed insects providing additional insight into the disruptive effects of these non-steroidal ecdysteroid agonists. © 2010 Elsevier Inc. All rights reserved.
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    20β-hydroxysteroid dehydrogenase gene promoter: Potential role for cyclic AMP and xenobiotic responsive elements
    ( 2012-11-01) Sreenivasulu, G. ; Senthilkumaran, B. ; Sudhakumari, C. C. ; Guan, G. ; Oba, Y. ; Kagawa, H. ; Nagahama, Y.
    Teleostean 20β-hydroxysteroid dehydrogenase (20β-HSD) is involved in final oocyte maturation and steroid hormone metabolism. It has structural and functional similarities to mammalian carbonyl reductases that are involved in the metabolism of endogenous carbonyl and xenobiotic compounds. To understand the transcriptional regulation of 20β-HSD, here we report the cloning of 20β-HSD promoter from two fish species, rainbow trout and air-breathing catfish. Analysis of the promoter motifs, in silico identified the presence of several sites for transcription factor binding including cAMP, xenobiotic and steroid hormone responsive elements. Luciferase reporter assays with progressive deletion constructs demonstrated that 20β-HSD type B of trout has no promoter activity while 20β-HSD type A of trout and catfish 20β-HSD promoters showed basal promoter activity. A TATA box flanked by a CAAT box is important for basal transcription. Deletion of cAMP responsive element in the promoter decreased basal promoter activity significantly. Reporter assays with forskolin and IBMX, drugs that increase intracellular cAMP induced the promoter activity over the basal level. Intriguingly, β-nafthoflavone, an arylhydrocarbon receptor ligand, induced the 20β-HSD promoter activity and is further evidenced by the induction of 20β-HSD expression in the livers of catfish, in vivo. These results demonstrate for the first time that 20β-HSD expression is not only modulated by cAMP but also by xenobiotics and further studies may provide significance to the ubiquitous distribution and broad substrate specificity of this enzyme. © 2012 Elsevier B.V.
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    5-lipoxygenase and cyclooxygenase inhibitory dammarane triterpenoid 1 from borassus flabellifer seed coat inhibits tumor necrosis factor-α secretion in lpsinduced thp-1 human monocytes and induces apoptosis in mia paca-2 pancreatic cancer cells
    ( 2015-08-01) Yarla, Nagendra Sastry ; Azad, Rajaram ; Basha, Mahaboob ; Rajack, Abdul ; Kaladhar, D. S.V.G.K. ; Allam, Bharat Kumar ; Pragada, Rajeswara Rao ; Singh, Krishna Nand ; Kumari K, Sunanda ; Pallu, Reddanna ; Parimi, Umadevi ; Bishayee, Anupam ; Duddukuri, Govinda Rao
    Phospholipase A2 (PLA2), Cyclooxygenase (COX) and 5-Lipoxygenase (5-LOX) are arachidonic acid metabolizing enzymes and their inhibitors have been developed as therapeutic molecules for cancer and inflammation related disorders. In the present study, PLA2, COX 1&2 and 5-LOX inhibitory studies of Borassus flabellifer seed coat extract were carried out and substantial 5-LOX inhibitory activity was found. Dammarane triterpenoid 1 (Dammara-20,23-diene-3,25-diol) was isolated according to 5-LOX activity guided isolation, and screened for COX (1 & 2) inhibitory activities. Dammarane triterpenoid 1 inhibited carrageenan-induced rat paw edema and TNF-α secretion levels in lipopolysaccharide (LPS)-induced THP-1 human monocytes. Anticancer activity studies demonstrated the antiproliferative effect of dammarane triterpenoid 1 on various cancer cell lines including MIA PaCa-2 pancreatic, DU145 prostate, HL-60 leukemia and Caco-2 colon cancers. Dammarane triterpenoid 1 showed good antiproliferative activity on MIA PaCa-2 pancreatic cancer cell line with IC50 of 12.36±0.33 μM, among other tested cell lines. Apoptosis inducing activity of dammarane triterpenoid 1 was confirmed based on increased sub-G0 phase cell population in cell cycle analysis, loss of mitochondrian membrane potential, elevated levels of cytochrome c, nuclear morphological changes and DNA fragmentation in MIA PaCa-2 pancreatic cancer cells. Therefore, dammarane triterpenoid skeleton may raise the hope of developing novel anti-inflammatory and anticancer drugs in the future.
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    5-Lipoxygenase: Its involvement in gastrointestinal malignancies
    ( 2018-07-01) Merchant, Neha ; Bhaskar, Lakkakula V.K.S. ; Momin, Saimila ; Sujatha, Peela ; Reddy, Aramati B.M. ; Nagaraju, Ganji Purnachandra
    Lipoxygenases (LOXs) are dioxygenases that catalyze the peroxidation of linoleic acid (LA) or arachidonic acid (AA), in the presence of molecular oxygen. The existence of inflammatory component in the tumor microenvironment intimately links the LOXs to gastrointestinal (GI) cancer progression. Amongst the six-different human LOX-isoforms, 5-LOX is the most vital enzyme for leukotriene (LT) biosynthesis, which is the main inflammation intermediaries. As recent investigations have shown the association of 5-LOX with tumor metastasis, there has also been significant progress in discovering the function of 5-LOX pathway in GI cancer. Studies on GI cancer cells using the pharmacological drugs targeting 5-LOX pathway have shown antiproliferative and proapoptotic effects. Pharmacogenetic discoveries in other diseases have revealed strong heritable basis for the leukotriene pathway, which helps in exploring the mechanistic source of genetic alteration within the leukotriene pathway and offer insights into GI cancer pathogenesis and future prospects for treatment and prevention. This review recapitulates the current research status of 5-LOX activity in GI malignancies.
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    A chromenoquinoline-based fluorescent off-on thiol probe for bioimaging
    ( 2012-02-13) Kand, Dnyaneshwar ; Kalle, Arunasree Marasanapalli ; Varma, Sreejith Jayasree ; Talukdar, Pinaki
    A new chromenoquinoline-based fluorescent off-on thiol probe 2 is reported. In aqueous buffer solutions at physiological pH, the probe exhibited 223-fold enhancement in fluorescence intensity by a Michael addition of cysteine to the maleimide appended to a chromenoquinoline. Cell permeability and live cell imaging of thiols are also demonstrated. © 2012 Royal Society of Chemistry.
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    A combined pharmacophore modeling, 3D QSAR, virtual screening, molecular docking, and ADME studies to identify potential HDAC8 inhibitors
    ( 2016-11-01) Debnath, Sudhan ; Debnath, Tanusree ; Majumdar, Swapan ; Arunasree, M. K. ; Aparna, Vema
    The World Cancer Report 2014 shows that cancer is a leading cause of death globally, and cancer related death is likely to go up by about 70 % in the next two decades. Among several target receptors of cancer, histone deacetylases are the promising therapeutic target for many cancers. The current study deals with a primary goal of identification of novel non-hydroxamic acid histone deacetylase 8 inhibitors. In this context, six featured pharmacophoric hypotheses with hydrogen bond acceptors (A), hydrogen bond donor (D), and aromatic ring (R) were generated using 36 reported histone deacetylase 8 inhibitors. Virtual screening of database using two pharmacophore hypothesis AAAADR.161 and AAADDR.189 resulted 2000 hits each having fitness score >1.503. The pharmacophore AAADDR.189 yielded statistically significant three-dimensional quantitative structure-activity relationship model with training set (R2: 0.9756, SD: 0.0680, F: 151.6, N: 26) and test set (Q2: 0.6922, Pearson R: 0.8705, N: 10) molecules. The R2pred value of the model was 0.6951, which confirmed the good predictive ability of the model for external data set. Hits resulted from virtual screening and known inhibitors were subjected to molecular docking study to identify the binding affinity of inhibitors with active site amino acid residues. Finally, absorption, distribution, metabolism, and excretion study were undertaken to determine the drug likeness properties of identified hits. On the basis of fitness score, predicted activities, XP Glide score, interacting amino acid residues of known inhibitors and absorption, distribution, metabolism, and excretion properties, ten structurally diverse hits are reported in this paper as potential histone deacetylase 8 inhibitors which reduce the cost of histone deacetylase 8 inhibitor discovery and enhance the process prior synthesis.
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    A comparison of computer aided drug design methods for calculating relative binding affinities of COX-2 inhibitors
    ( 2006-01-01) Amaravani, M. ; Reddy, R. Nageswara ; Mutyala, R. ; Reddy, G. V. ; Reddanna, P. ; Reddy, M. Rami
    Computational assessment of the binding affinity of enzyme inhibitors prior to synthesis is an important component of computer-aided drug design paradigms. The free energy perturbation methodology is the most accurate means of estimating relative binding affinities between two inhibitors. However, due to its complexity and computation-intensive nature, practical applications are restricted to analysis of structurally-related inhibitors. Accordingly, there is a need for methods that enable rapid assessment of a large number of structurally-unrelated molecules in a suitably accurate manner. In this article, the free energy perturbation method is compared with molecular mechanics methods to assess the advantages of each in the estimation of relative binding affinities of COX-2 inhibitors. Qualitative predictions of relative binding free energies of COX-2 inhibitors using molecular mechanics methods are discussed and compared with the corresponding free energy perturbation results. The results indicate that the molecular mechanics based methods are useful in the qualitative assessment, while the free energy methods are useful in the quantitative assessment of relative binding affinities of enzyme inhibitors.
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    A comprehensive gene expression meta-analysis identifies novel immune signatures in rheumatoid arthritis patients
    ( 2017-02-02) Afroz, Sumbul ; Giddaluru, Jeevan ; Vishwakarma, Sandeep ; Naz, Saima ; Khan, Aleem Ahmed ; Khan, Nooruddin
    Rheumatoid arthritis (RA), a symmetric polyarticular arthritis, has long been feared as one of the most disabling forms of arthritis. Identification of gene signatures associated with RA onset and progression would lead toward development of novel diagnostics and therapeutic interventions. This study was undertaken to identify unique gene signatures of RA patients through large-scale meta-profiling of a diverse collection of gene expression data sets. We carried out a meta-analysis of 8 publicly available RA patients' (107 RA patients and 76 healthy controls) gene expression data sets and further validated a few meta-signatures in RA patients through quantitative real-time PCR (RT-qPCR). We identified a robust meta-profile comprising 33 differentially expressed genes, which were consistently and significantly expressed across all the data sets. Our meta-analysis unearthed upregulation of a few novel gene signatures including PLCG2, HLA-DOB, HLA-F, EIF4E2, and CYFIP2, which were validated in peripheral blood mononuclear cell samples of RA patients. Further, functional and pathway enrichment analysis reveals perturbation of several meta-genes involved in signaling pathways pertaining to inflammation, antigen presentation, hypoxia, and apoptosis during RA. Additionally, PLCG2 (phospholipase Cγ2) popped out as a novel meta-gene involved in most of the pathways relevant to RA including inflammasome activation, platelet aggregation, and activation, thereby suggesting PLCG2 as a potential therapeutic target for controlling excessive inflammation during RA. In conclusion, these findings highlight the utility of meta-analysis approach in identifying novel gene signatures that might provide mechanistic insights into disease onset, progression and possibly lead toward the development of better diagnostic and therapeutic interventions against RA.
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    A fluorescence based assay with pyranine labeled hexa-histidine tagged organophosphorus hydrolase (OPH) for determination of organophosphates
    ( 2012-03-01) Thakur, Shaveena ; Venkateswar Reddy, M. ; Siddavattam, Dayananda ; Paul, A. K.
    Organophosphorus hydrolase has been employed extensively for catalysis based biosensor synthesis with optical, potentiometric and amperometric based detection mechanism. The present study reports the response of bioconjuagtes prepared by utilizing OPH and pH sensitive polyanionic fluorophore i.e. pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt) in different molar ratios by the aid of electrostatic force. Two types of bioconjugates were prepared, one of them contained mature form of OPH obtained from Escherichia coli cells expressing organophosphate degrading (opd) gene from a tac promoter, whereas the variant OPH 6His, has 6× histidine tail at C-terminus. The investigation was carried out utilizing the bioconjugates of different molar ratios prepared with both the enzymes and ratio showing maximum degree of labeling with pyranine was selected for the detection of organophosphates in standard samples. The lower limit of detection for paraoxon was ∼20 ppb and for methyl parathion and coumaphos it was ∼50 ppb under optimized conditions (55-60 °C) with the reaction time of 3 min. These features of the prepared conjugate make it a strong contender for the development of the field deployable biosensor for organophosphates estimation. © 2012 Elsevier B.V. All rights reserved.
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    A lipid-modified estrogen derivative that treats breast cancer independent of estrogen receptor expression through simultaneous induction of autophagy and apoptosis
    ( 2011-03-01) Sinha, Sutapa ; Roy, Sayantani ; Reddy, Bathula Surendar ; Pal, Krishnendu ; Sudhakar, Godeshala ; Iyer, Seethalakshmi ; Dutta, Shamit ; Wang, Enfeng ; Vohra, Pawan Kumar ; Roy, Karnati Rammohan ; Reddanna, Pallu ; Mukhopadhyay, Debabrata ; Banerjee, Rajkumar
    It is a challenge to develop a universal single drug that can treat breast cancer at single- or multiple-stage complications, yet remains nontoxic to normal cells. The challenge is even greater when breast cancer-specific, estrogen-based drugs are being developed that cannot act against multistaged breast cancer complications owing to the cells differential estrogen receptor (ER) expression status and their possession of drug-resistant and metastatic phenotypes. We report here the development of a first cationic lipid-conjugated estrogenic derivative (ESC8) that kills breast cancer cells independent of their ER expression status. This ESC8 molecule apparently is nontoxic to normal breast epithelial cells, as well as to other noncancer cells. ESC8 induces apoptosis through an intrinsic pathway in ER-negative MDA-MB-231 cells. In addition, ESC8 treatment induces autophagy in these cells by interfering with the mTOR activity. This is the first example of an estrogen structure-based molecule that coinduces apoptosis and autophagy in breast cancer cells. Further in vivo study confirms the role of this molecule in tumor regression. Together, our results open new perspective of breast cancer chemotherapy through a single agent, which could provide the therapeutic benefit across all stages of breast cancer. ©2011 AACR.
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    A lipid-modified estrogen derivative that treats breast cancer independent of estrogen receptor expression through simultaneous induction of autophagy and apoptosis
    ( 2011-03-01) Sinha, Sutapa ; Roy, Sayantani ; Reddy, Bathula Surendar ; Pal, Krishnendu ; Sudhakar, Godeshala ; Iyer, Seethalakshmi ; Dutta, Shamit ; Wang, Enfeng ; Vohra, Pawan Kumar ; Roy, Karnati Rammohan ; Reddanna, Pallu ; Mukhopadhyay, Debabrata ; Banerjee, Rajkumar
    It is a challenge to develop a universal single drug that can treat breast cancer at single- or multiple-stage complications, yet remains nontoxic to normal cells. The challenge is even greater when breast cancer-specific, estrogen-based drugs are being developed that cannot act against multistaged breast cancer complications owing to the cells differential estrogen receptor (ER) expression status and their possession of drug-resistant and metastatic phenotypes. We report here the development of a first cationic lipid-conjugated estrogenic derivative (ESC8) that kills breast cancer cells independent of their ER expression status. This ESC8 molecule apparently is nontoxic to normal breast epithelial cells, as well as to other noncancer cells. ESC8 induces apoptosis through an intrinsic pathway in ER-negative MDA-MB-231 cells. In addition, ESC8 treatment induces autophagy in these cells by interfering with the mTOR activity. This is the first example of an estrogen structure-based molecule that coinduces apoptosis and autophagy in breast cancer cells. Further in vivo study confirms the role of this molecule in tumor regression. Together, our results open new perspective of breast cancer chemotherapy through a single agent, which could provide the therapeutic benefit across all stages of breast cancer. ©2011 AACR.
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    A new approach to construct a fused 2-ylidene chromene ring: Highly regioselective synthesis of novel chromeno quinoxalines
    ( 2012-06-28) Shiva Kumar, K. ; Rambabu, D. ; Prasad, Bagineni ; Mujahid, Mohammad ; Krishna, G. Rama ; Basaveswara Rao, M. V. ; Malla Reddy, C. ; Vanaja, G. R. ; Kalle, Arunasree M. ; Pal, Manojit
    Regioselective construction of a fused 2-ylidene chromene ring was achieved for the first time by using AlCl 3-induced C-C bond formation followed by Pd/C-Cu mediate coupling-cyclization strategy. A number of chromeno[4,3-b]quinoxaline derivatives were prepared by using this strategy. Single crystal X-ray diffraction study of a representative compound e.g. 6-(2,2-dimethylpropylidene)-4-methyl-6H-chromeno[4,3-b]quinoxalin-3-ol confirmed the presence of an exocyclic C-C double bond with Z-geometry. The crystal structure analysis and hydrogen bonding patterns of the same compound along with its structure elaboration via propargylation followed by Sonogashira coupling of the resulting terminal alkyne is presented. A probable mechanism for the formation of 2-ylidene chromene ring is discussed. Some of the compounds synthesized showed anticancer properties when tested in vitro. © 2012 The Royal Society of Chemistry.
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    A New Pathway for the Biosynthesis of Leukotriene F4
    ( 1988-01-01) REDDANNA, P. ; WHELAN, J. ; REDDY, C. C.
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    A Novel and Conserved Plasmodium Sporozoite Membrane Protein SPELD is Required for Maturation of Exo-erythrocytic Forms
    ( 2017-01-09) Al-Nihmi, Faisal Mohammed Abdul ; Kolli, Surendra Kumar ; Reddy, Segireddy Rameswara ; Mastan, Babu S. ; Togiri, Jyothi ; Maruthi, Mulaka ; Gupta, Roshni ; Sijwali, Puran Singh ; Mishra, Satish ; Kumar, Kota Arun
    Plasmodium sporozoites are the infective forms of malaria parasite to vertebrate host and undergo dramatic changes in their transcriptional repertoire during maturation in mosquito salivary glands. We report here the role of a novel and conserved Plasmodium berghei protein encoded by PBANKA-091090 in maturation of Exo-erythrocytic Forms (EEFs) and designate it as Sporozoite surface Protein Essential for Liver stage Development (PbSPELD). PBANKA-091090 was previously annotated as PB402615.00.0 and its transcript was recovered at maximal frequency in the Serial Analysis of the Gene Expression (SAGE) of Plasmodium berghei salivary gland sporozoites. An orthologue of this transcript was independently identified in Plasmodium vivax sporozoite microarrays and was designated as Sporozoite Conserved Orthologous Transcript-2 (scot-2). Functional characterization through reverse genetics revealed that PbSPELD is essential for Plasmodium liver stage maturation. mCherry transgenic of PbSPELD localized the protein to plasma membrane of sporozoites and early EEFs. Global microarray analysis of pbspeld ko revealed EEF attenuation being associated with down regulation of genes central to general transcription, cell cycle, proteosome and cadherin signaling. pbspeld mutant EEFs induced pre-erythrocytic immunity with 50% protective efficacy. Our studies have implications for attenuating the human Plasmodium liver stages by targeting SPELD locus.
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    A novel meta-cleavage product hydrolase from Flavobacterium sp. ATCC27551
    ( 2006-12-22) Khajamohiddin, Syed ; Babu, Pakala Suresh ; Chakka, Deviprasanna ; Merrick, Mike ; Bhaduri, Anirban ; Sowdhamini, Ramanathan ; Siddavattam, Dayananda
    The organophosphate degrading (opd) gene cluster of plasmid pPDL2 of Flavobacterium sp. ATCC27551 contains a novel open-reading frame, orf243. This was predicted to encode an α/β hydrolase distantly related to the meta-fission product (MFP) hydrolases such as XylF, PhnD, and CumD. By homology modeling Orf243 has most of the structural features of MFP hydrolases including the characteristic active site catalytic triad. The purified protein (designated MfhA) is a homotetramer and shows similar affinity for 2-hydroxy-6-oxohepta-2,4-dienoate (HOHD), 2-hydroxymuconic semialdehyde (HMSA), and 2-hydroxy-5-methylmuconic semialdehyde (HMMSA), the meta-fission products of 3-methyl catechol, catechol, and 4-methyl catechol. The unique catalytic properties of MfhA and the presence near its structural gene of cis-elements required for transposition suggest that mfhA has evolved towards encoding a common hydrolase that can act on meta-fission products containing either aldehyde or ketone groups. © 2006 Elsevier Inc. All rights reserved.
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    A novel phosphorylation by AMP-activated kinase regulates RUNX2 from ubiquitination in osteogenesis over adipogenesis article
    ( 2018-07-01) Chava, Suresh ; Chennakesavulu, S. ; Gayatri, Meher B. ; Reddy, Aramati B.M.
    Mesenchymal stem cells (MSCs) function as progenitors to a variety of cell types. The reported association between osteogenic and adipogenic commitment during differentiation is due to the regulation of key transcription factors in the signaling pathways. However, the process of adipogenesis at the expense of osteogenic phenotype during metabolic stress is still unclear. In this study, we showed for the first time that RUNX2 is a novel substrate of AMP-activated kinase (AMPK), which directly phosphorylates at serine 118 residue in the DNA-binding domain of RUNX2. Our results in in vitro MSC lineage differentiation models confirmed that active AMPK and RUNX2-S118 phosphorylation are preferentially associated with osteogenic commitment, whereas the lack of this phosphorylation leads to adipogenesis. This interplay is regulated by the ubiquitination of non-phosphorylated RUNX2-S118, which is evident in the dominant mutant RUNX2-S118D. Pharmacological activation of AMPK by metformin significantly abrogated the loss of RUNX2-S118 phosphorylation and protected from tunicamycin-induced endoplasmic reticulum stress, high glucose-induced in vitro adipogenesis and streptozotocin-induced in vivo bone adiposity and bone phenotype. In conclusion, results from this study demonstrated that RUNX2 is a direct target of AMPK which simplified the outlook towards several complex mechanisms that are currently established concerning cellular metabolism and pathogenesis.