@article { ISI:000242621800023, title = {Molecular interactions between the specialist herbivore Manduca sexta (Lepidoptera, Sphingidae) and its natural host Nicotiana attenuata. VII. changes in the plant{\textquoteright}s proteome}, journal = {Plant Physiology}, volume = {142}, number = {4}, year = {2006}, month = {DEC}, pages = {1621-1641}, publisher = {AMER SOC PLANT BIOLOGISTS}, type = {Article}, address = {15501 MONONA DRIVE, ROCKVILLE, MD 20855 USA}, abstract = {

When Manduca sexta attacks Nicotiana attenuata, fatty acid-amino acid conjugates (FACs) in the larvae{\textquoteright}s oral secretions (OS) are introduced into feeding wounds. These FACs trigger a transcriptional response that is similar to the response induced by insect damage. Using two-dimensional gel electrophoresis, matrix-assisted laser desorption ionization-time of flight, and liquid chromatography-tandem mass spectrometry, we characterized the proteins in phenolic extracts and in a nuclear fraction of leaves elicited by larval attack, and/or in leaves wounded and treated with OS, FAC-free OS, and synthetic FACs. Phenolic extracts yielded approximately 600 protein spots, many of which were altered by elicitation, whereas nuclear protein fractions yielded approximately 100 spots, most of which were unchanged by elicitation. Reproducible elicitor-induced changes in 90 spots were characterized. In general, proteins that increased were involved in primary metabolism, defense, and transcriptional and translational regulation; those that decreased were involved in photosynthesis. Like the transcriptional defense responses, proteomic changes were strongly elicited by the FACs in OS. A semiquantitative reverse transcription-PCR approach based on peptide sequences was used to compare transcript and protein accumulation patterns for 17 candidate proteins. In six cases the patterns of elicited transcript accumulation were consistent with those of elicited protein accumulation. Functional analysis of one of the identified proteins involved in photosynthesis, RuBPCase activase, was accomplished by virus-induced gene silencing. Plants with decreased levels of RuBPCase activase protein had reduced photosynthetic rates and RuBPCase activity, and less biomass, responses consistent with those of herbivore-attacked plants. We conclude that the response of the plant{\textquoteright}s proteome to herbivore elicitation is complex, and integrated transcriptome-proteome-metabolome analysis is required to fully understand this ubiquitous ecological interaction.

}, issn = {0032-0889}, doi = {10.1104/pp.106.088781}, author = {Giri, Ashok P. and Wuensche, Hendrik and Mitra, Sirsha Sribas and Zavala, Jorge A. and Muck, Alexander and Svatos, Ales and Baldwin, Ian T.} } @article { ISI:000326615000007, title = {Molecular insights into resistance mechanisms of lepidopteran insect pests against toxicants}, journal = {Journal of Proteome Research}, volume = {12}, number = {11}, year = {2013}, month = {NOV}, pages = {4727-4737}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Insect pests remain a major reason for crop loss worldwide despite extensive use of chemical insecticides. More than B 50\% of all insecticides are organophosphates, followed by synthetic pyrethroids, organochlorines, carbamates, and biopesticides, and their continued use may have many environmental, agricultural, medical, and socioeconomic issues. Importantly, only a countable number of insects have acquired the status of crop pests, mostly due to monoculture of crop plants and polyphagous nature of the insects. We focus on A adaptations of Lepidopteran insects to phytochemicals and synthetic pesticides in native and modern agricultural systems. Because of heavy use of chemical insecticides, a strong selection pressure is imposed on insect populations, resulting in the emergence of resistance against candidate compound(s). Current knowledge suggests that insects generally implement a three-tier system to overcome the effect of toxic compounds at physiological, biochemical, and genetic levels. Furthermore, we have discussed whether the adaptation to phytochemicals provides an advantage to the insect while encountering synthetic insecticide molecules. Specific metabolic pathways employed by insects to convert deterrents into less toxic forms or their removal from the system are highlighted. Using the proteomics approach, insect proteins interacting with insecticides can be identified, and their modification in resistant insects can be characterized. Also, systems biology studies can offer useful cues to decipher the molecular networks participating in the metabolism of detrimental compounds.

}, keywords = {field crops, insect-pests, insecticide, Lepidoptera, proteomics, resistance mechanisms}, issn = {1535-3893}, doi = {10.1021/pr400642p}, author = {Dawkar, Vishal V. and Chikate, Yojana R. and Lomate, Purushottam R. and Dholakia, Bhushan B. and Gupta, Vidya S. and Giri, Ashok P.} } @article { ISI:000357438200013, title = {Metabolic profiling of chickpea-Fusarium interaction identifies differential modulation of disease resistance pathways}, journal = {Phytochemistry}, volume = {116}, year = {2015}, month = {AUG}, pages = {120-129}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Chickpea is the third most widely grown legume in the world and mainly used as a vegetarian source of human dietary protein. Fusarium wilt, caused by Fusarium oxysporum f. sp. ciceri (Foc), is one of the major threats to global chickpea production. Host resistance is the best way to protect crops from diseases; however, in spite of using various approaches, the mechanism of Foc resistance in chickpea remains largely obscure. In the present study, non-targeted metabolic profiling at several time points of resistant and susceptible chickpea cultivars using high-resolution liquid chromatography-mass spectrometry was applied to better understand the mechanistic basis of wilt resistance or susceptibility. Multivariate analysis of the data (OPLS-DA) revealed discriminating metabolites in chickpea root tissue after Foc inoculation such as flavonoids, isoflavonoids, alkaloids, amino acids and sugars. Foc inoculated resistant plants had more flavonoids and isoflavonoids along with their malonyl conjugates. Many antifungal metabolites that were induced after Foc infection viz, aurantion-obstine beta-glucosides and querecitin were elevated in resistant cultivar. Overall, diverse genetic and biochemical mechanisms were operational in the resistant cultivar for Foc defense as compared to the susceptible plant. The resistant chickpea plants employed the above-mentioned metabolic pathways as potential defense strategy against Foc. (C) 2015 Elsevier Ltd. All rights reserved.

}, keywords = {Chickpea, Fusarium wilt, LC-MS, Metabolomics, OPLS-DA, Phytoalexin}, issn = {0031-9422}, doi = {10.1016/j.phytochem.2015.04.001}, author = {Kumar, Yashwant and Dholakia, Bhushan B. and Panigrahi, Priyabrata and Kadoo, Narendra Y. and Giri, Ashok P. and Gupta, Vidya S.} } @article { ISI:000374286500004, title = {Molecular cloning and characterization of O-methyltransferase from mango fruit (mangifera indica cv. alphonso)}, journal = {Molecular Biotechnology}, volume = {58}, number = {5}, year = {2016}, month = {MAY}, pages = {340-350}, publisher = {HUMANA PRESS INC}, address = {999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 USA}, abstract = {

Flavour of ripe Alphonso mango is invariably dominated by the de novo appearance of lactones and furanones during ripening. Of these, furanones comprising furaneol (4-hydroxy-2,5-dimethyl-3(2H)-furanone) and mesifuran (2,5-dimethyl-4-methoxy-3(2H)-furanone) are of particular importance due to their sweet, fruity caramel-like flavour characters and low odour detection thresholds. We isolated a 1056 bp complete open reading frame of a cDNA encoding S-adenosyl-l-methionine-dependent O-methyltransferase from Alphonso mango. The recombinantly expressed enzyme, MiOMTS showed substrate specificity towards furaneol and protocatechuic aldehyde synthesizing mesifuran and vanillin, respectively, in an in vitro assay reaction. A semi-quantitative PCR analysis showed fruit-specific expression of MiOMTS transcripts. Quantitative real-time PCR displayed ripening-related expression pattern of MiOMTS in both pulp and skin of Alphonso mango. Also, early and significantly enhanced accumulation of its transcripts was detected in pulp and skin of ethylene-treated fruits. Ripening-related and fruit-specific expression profile of MiOMTS and substrate specificity towards furaneol is a suggestive of its involvement in the synthesis of mesifuran in Alphonso mango. Moreover, a significant trigger in the expression of MiOMTS transcripts in ethylene-treated fruits point towards the transcriptional regulation of mesifuran biosynthesis by ethylene.

}, keywords = {Ethylene, expression, Flavour, Mango, Mesifuran, Ripening}, issn = {1073-6085}, doi = {10.1007/s12033-016-9933-2}, author = {Chidley, Hemangi G. and Oak, Pranjali S. and Deshpande, Ashish B. and Pujari, Keshav H. and Giri, Ashok P. and Gupta, Vidya S.} } @article {46619, title = {Molecular determinant for specificity: differential interaction of alpha-amylases with their proteinaceous inhibitors}, journal = {Biochimica Et Biophysica Acta-General Subjects}, volume = {1864}, year = {2020}, month = {DEC}, pages = {129703}, type = {Review}, abstract = {

Background: alpha-Amylase inhibitors (alpha-AIs) belong to the discrete classes, and exhibited differential specificities against alpha-amylases from various sources. Several alpha-amylases and their complexes with inhibitors at the molecular level have been studied in detail. Interestingly, some alpha-AIs depict specific and selective interactions amid different insect alpha-amylases. Scope of review: There are studies to understand evolutionary variability and functional differentiation of insect alpha-amylases and their cognate inhibitors. We have examined sequence, structural, and interaction diversity between various alpha-amylases and alpha-AIs. Based on these analyses, we are providing a potential basis for the functional differentiation among certain insect a-amylases concerning mammalian counterparts and their interactions with different proteinaceous alpha-AIs. Major conclusions: Insect alpha-amylases have conserved domain architecture with differences in length, number of disulfide bonds, and secondary structure. Furthermore, few of them exhibit variable characteristics like chloride dependent activity, the presence of N-terminal glutamine residue to protect against proteolytic degradation, and loop variations near the enzyme active site. Conformation of alpha-AI protein could be an essential factor for their specificity and binding affinities towards target alpha-amylase(s). Furthermore, variation into the enzyme binding pocket residues might contribute to differential interactions with inhibitors. General significance: Molecular insights in the interactions between insect alpha-amylases and plant alpha-AI will provide the details of mechanisms assisting the inhibitor specificity. Furthermore, this information will help to design potent and effective alpha-AIs against specific alpha-amylase.

}, keywords = {Active site, alpha-amylase, alpha-amylase inhibitor, Insect, molecular interactions}, issn = {0304-4165}, doi = {10.1016/j.bbagen.2020.129703}, author = {Rane, Ashwini S. and Joshi, Rakesh S. and Giri, Ashok P.} } @article {46637, title = {Molecular investigation of coleopteran specific alpha-amylase inhibitors from amaranthaceae members}, journal = {International Journal of Biological Macromolecules}, volume = {163}, year = {2020}, month = {NOV}, pages = {1444-1450}, type = {Article}, abstract = {

alpha-Amylase inhibitors (alpha-AIs) target alpha-amylases and interfere with the carbohydrate digestion of insects. Among different classes of alpha-AIs, a knottin-type inhibitor from Amaranthus hypochondriacus (AhAI) was found to be specific against coleopteran storage pests. In this report, we have characterized three previously unidentified knottin-type alpha-AIs from various Amaranthaceae plants namely, Amaranthus hypochondriacus (AhAI2), Alternanthera sessilis (AsAI) and Chenopodium quinoa (CqAI). They contain a signal peptide, pro-peptide, and mature peptide. The mature peptides of the new alpha-AIs shared 68 to 78\% identity with AhAI and have highly variable pro-peptide regions. Along with the cystine-knot fold, they showed conservation of reactive site residues. All recombinant alpha-AIs were successfully expressed in their active form and native state using an oxidative cytoplasmic environment. Inhibition studies against various amylases revealed that these inhibitors showed selective inhibition of coleopteran recombinant insect alpha-amylases viz., Tribolium castaneum, and Callosobruchus chinensis. Tribolium castaneum alpha-amylase inhibition potency was highest for AhAI2 (Ki similar to 15 mu M) followed by AsAI (Ki similar to 43 mu M) and CqAI (Ki similar to 61 mu M). Interaction analysis of these inhibitors illustrated that the reactive site of inhibitors make several non-covalent interactions with the substrate-binding pocket of coleopteran alpha-amylases. The selectivity of these inhibitors against coleopteran a-amylases highlights their potential in storage grain pest control. (C) 2020 Elsevier B.V. All rights reserved.

}, keywords = {alpha-amylase, alpha-amylase inhibitor, Amaranthaceae, Coleoptera, Knottin-type}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2020.07.219}, author = {Rane, Ashwini S. and Venkatesh, Varun and Joshi, Rakesh S. and Giri, Ashok P.} } @article {49358, title = {Multi-dimensional impact of captopril modification on human serum albumin}, journal = {International Journal of Biological Macromolecules}, volume = {274}, year = {2024}, month = {AUG}, pages = {133289}, type = {Article}, abstract = {

Captopril is a thiol drug, widely used for the management of hypertension and cardiovascular diseases. Reactive thiols are found to covalently modify the cysteines of plasma proteins and affect their structure and function. Human serum albumin (HSA) is prone to undergo modification by various low molecular weight compounds, including drugs. Cysteine34 (Cys34) in HSA has a free thiol group with antioxidant properties, considered to be the most redox-sensitive amino acid in plasma. Through mass-spectrometric analysis, we demonstrate for the first time that captopril forms a disulfide adduct at Cys34 residue and increases the protease susceptibility of HSA to trypsin. As evidenced by our biophysical and electron microscopy studies, HSA undergoes structural alteration, aggregation and morphological changes when treated with different captopril concentrations. Molecular dynamics studies further revealed the regions of secondary structural changes in HSA due to disulfide adduct formation by captopril at Cys34. It also elucidated the residues involved in the noncovalent interactions with captopril. It is envisaged that structural change in HSA may influence the efficacy of drug delivery as well as its own biological function. These findings may thus provide significant insights into the field of pharmacology intriguing further investigation into the effects of long-term captopril treatment.

}, keywords = {Captopril, Electron microscopy, Human serum albumin, Mass spectrometry, Molecular dynamic simulation, Spectrophotometry}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2024.133289}, author = {Ghosh, Amrita and Jani, Vinod and Sonavane, Uddhavesh and Naphade, Anvi N. and Joshi, Rajendra and Kulkarni, Mahesh J. and Giri, Ashok P.} } @article {49508, title = {MYB proteins: Versatile regulators of plant development, stress responses, and secondary metabolite biosynthetic pathways}, journal = {International Journal of Biological Macromolecules}, volume = {288}, year = {2025}, month = {FEB}, pages = {138588}, type = {Review}, abstract = {

MYB proteins are ubiquitous in nature, regulating key aspects of plant growth and development. Although MYB proteins are known for regulating genes involved in secondary metabolite biosynthesis, particularly phenylpropanoids, their roles in terpenoid, glucosinolate, and alkaloid biosynthesis remain less understood. This review explores the structural and functional differences between activator and repressor MYB proteins along with their roles in plant growth, development, stress responses, and secondary metabolite production. MYB proteins serve as central hubs in protein-protein interaction networks that regulate expression of numerous genes involved in the adaptation of plants to varying environmental conditions. Thus, we also highlight key interacting partners of MYB proteins and their roles in these adaptation mechanisms. We further discuss the mechanisms regulating MYB proteins, including autoregulation, epigenetics, and post-transcriptional and post-translational modifications. Overall, we propose MYB proteins as versatile regulators for improving plant traits, stress responses, and secondary metabolite production.

}, keywords = {Activator, defense, Development, MYB protein, Repressor, Secondary metabolites}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2024.138588}, author = {Bhatt, Preshita A. and Gurav, Tanuja P. and Kondhare, Kirtikumar R. and Giri, Ashok P.} }