Publications by authors named "Kollipara Padmasree"

In higher plants, the mitochondrial alternative oxidase (AOX) pathway plays an essential role in maintaining the TCA cycle/cellular carbon and energy balance under various physiological and stress conditions. Though the activation of AOX pathway upon exogenous addition of α-ketoacids/TCA cycle metabolites [pyruvate, α-ketoglutarate (α-KG), oxaloacetic acid (OAA), succinate and malic acid] to isolated mitochondria is known, the molecular mechanism of interaction of these metabolites with AOX protein is limited. The present study is designed to understand the biomolecular interaction of pure recombinant Arabidopsis thaliana AOX1A with TCA cycle metabolites under in vitro conditions using various biophysical and molecular docking studies.

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The current experimental data unveils the role of brassinolide (BL), a phytohormone of class brassinosteroids (BRs), in augmenting the cross-talk between the mitochondrial electron transport chain (mETC) and chloroplasts to strengthen the efficiency of the Calvin-Benson cycle (CBC) for higher assimilation of carbon dioxide in the mesophyll cell protoplasts (MCP) of . The outcome of total respiration (TR) and photosynthetic carbon assimilation (PCA) was monitored as O uptake under dark and NaHCO-dependent O evolution under light, respectively, after pre-incubation of MCP at a broad spectrum of BL concentration from 0.05 pM to 5 pM at 25 °C and optimum light intensity of 1000 μmol m s.

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Bowman-Birk inhibitor (BBI ~10 kDa) and Kunitz inhibitor (KI ~20 kDa) are serine protease/proteinase inhibitor(s) [PI(s)] ubiquitously found in several Leguminous plant species with insecticidal and therapeutic properties. Due to narrow molecular mass differences, the separation of these inhibitors from a single seed variety is tedious. The present study is aimed to develop a rapid protocol (<24 h) for purifying BBI and KI from legume seeds using mild trichloroacetic acid (TCA) extraction followed by trypsin-affinity chromatography.

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In higher plants, alternative oxidase (AOX) participates in a cyanide resistant and non-proton motive electron transport pathway of mitochondria, diverging from the ubiquinone pool. The physiological significance of AOX in biotic/abiotic stress tolerance is well-documented. However, its structural and biophysical properties are poorly understood as its crystal structure is not yet revealed in plants.

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The midgut of lepidopteran larvae is a multifunctional tissue that performs roles in digestion, absorption, immunity, transmission of pathogens and interaction with ingested various molecules. The proteins localized at the inner apical brush border membrane are primarily digestive proteases, but some of them, like aminopeptidase N, alkaline phosphatase, cadherins, ABC transporter C2, etc., interact with Crystal (Cry) toxins produced by ().

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Article Synopsis
  • Proteinase/Protease inhibitors (PIs) from plants, like the Bowman-Birk Inhibitor (BBI) isolated from a hybrid peanut variety, serve as important defenses against insect pests and pathogens.* -
  • The purified BBI exhibited specific characteristics such as low molecular mass, a stable structure, and the ability to inhibit trypsin while affecting the expression of other midgut proteases in certain insects.* -
  • Feeding experiments demonstrated that BBI significantly reduced larval growth and protease activity in insects, indicating its potential as a natural insecticide in enhancing plant resistance.*
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Rhynchosia sublobata, a wild relative of pigeonpea, possesses defensive proteinase/protease inhibitors (PIs). Characterization of trypsin specific PIs (RsPI) separated from seeds by column chromatography using 2-D gel electrophoresis and Edman degradation method identified R. sublobata possessed both Bowman-Birk isoinhibitors (RsBBI) and Kunitz isoinhibitors (RsKI).

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Crude proteinase inhibitors (CPIs) extracted from the seeds of Rhynchosia sublobata, a wild relative of pigeon pea showed pronounced inhibitory activity on the larval gut trypsin-like proteases of lepidopteran insect pest - Achaea janata. Consequently, a full-length cDNA of Bowman-Birk inhibitor gene (RsBBI1) was cloned from the immature seeds of R. sublobata.

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Proteinase inhibitors (PIs) are natural defense proteins of plants found to be active against gut proteases of various insects. A pigeonpea wild relative Cajanus platycarpus was identified as a source of resistance against Helicoverpa armigera, a most devastating pest of several crops including pigeonpea. In the light of earlier studies, trypsin-specific PIs (CpPI 63) were purified from mature dry seeds of C.

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Lignin is the second most abundant renewable biopolymer on earth after cellulose. It is being used in many industrial applications due to its abundance. In the present study, lignin was isolated from the stems of Leucaena leucocephala (Lam.

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The utilization of nanomaterials in the domain of agriculture is at an inception, especially in the development of controlled release agrochemical nanoformulations. The present study demonstrated the potential of subabul stem lignin as a matrix material in agrochemical formulations using nanotechnology. In this study, "nanoprecipitation" method was employed and "optimized" to fabricate a stable herbicide, "diuron nanoformulation" (DNF).

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This study aimed to validate the physiological importance of Arabidopsis thaliana alternative oxidase 1a (AtAOX1a) in alleviating oxidative stress using Saccharomyces cerevisiae as a model organism. The AOX1a transformant (pYES2AtAOX1a) showed cyanide resistant and salicylhydroxamic acid (SHAM)-sensitive respiration, indicating functional expression of AtAOX1a in S. cerevisiae.

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The present study reveals the importance of alternative oxidase (AOX) pathway in optimizing photosynthesis under osmotic and temperature stress conditions in the mesophyll protoplasts of Pisum sativum. The responses of photosynthesis and respiration were monitored at saturating light intensity of 1000 μmoles m(-2) s(-1) at 25°C under a range of sorbitol concentrations from 0.4 to 1.

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Background And Aims: The importance of the alternative oxidase (AOX) pathway, particularly AOX1A, in optimizing photosynthesis during de-etiolation, under elevated CO2, low temperature, high light or combined light and drought stress is well documented. In the present study, the role of AOX1A in optimizing photosynthesis was investigated when electron transport through the cytochrome c oxidase (COX) pathway was restricted at complex III.

Methods: Leaf discs of wild-type (WT) and aox1a knock-out mutants of Arabidopsis thaliana were treated with antimycin A (AA) under growth-light conditions.

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Proteinase inhibitors (C11PI) from mature dry seeds of Cajanus cajan (cv. ICP 7118) were purified by chromatography which resulted in 87-fold purification and 7.9% yield.

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Ethnopharmacological Relevance: Ocimum sanctum (OS), commonly known as Holy basil/Tulsi, has been traditionally used to treat cardiovascular diseases (CVD) and manage general cardiac health. The present study is designed to evaluate the antiinflammatory effect of O. sanctum and its phenolic compound and eugenol (EUG) in human monocytic (THP-1) cells and validate its traditional use for treating cardiovascular diseases.

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As plants are sessile, they often face high light (HL) stress that causes damage of the photosynthetic machinery leading to decreased photosynthesis. The importance of alternative oxidase (AOX) in optimizing photosynthesis is well documented. In the present study, the role of AOX in sustaining photosynthesis under HL was studied using AOX1a knockout mutants (aox1a) of Arabidopsis thaliana.

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Brassica juncea annexin-3 (BjAnn3) was functionally characterized for its ability to modulate H2O2-mediated oxidative stress in Saccharomyces cerevisiae. BjAnn3 showed a significant protective role in cellular-defense against oxidative stress and partially alleviated inhibition of mitochondrial respiration in presence of exogenously applied H2O2. Heterologous expression of BjAnn3 protected membranes from oxidative stress-mediated damage and positively regulated antioxidant gene expression for ROS detoxification.

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The present study shows the importance of alternative oxidase (AOX) pathway in optimizing photosynthesis under high light (HL). The responses of photosynthesis and respiration were monitored as O(2) evolution and O(2) uptake in mesophyll protoplasts of pea pre-incubated under different light intensities. Under HL (3000 micromol m(-2) s(-1)), mesophyll protoplasts showed remarkable decrease in the rates of NaHCO(3)-dependent O(2) evolution (indicator of photosynthetic carbon assimilation), while decrease in the rates of respiratory O(2) uptake were marginal.

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The present study suggests the importance of reactive oxygen species (ROS) and antioxidant metabolites as biochemical signals during the beneficial interactions of mitochondrial metabolism with photosynthetic carbon assimilation at saturating light and optimal CO2. Changes in steady-state photosynthesis of pea mesophyll protoplasts monitored in the presence of antimycin A [AA, inhibitor of cytochrome oxidase (COX) pathway] and salicylhydroxamic acid [SHAM, inhibitor of alternative oxidase (AOX) pathway] were correlated with total cellular ROS and its scavenging system. Along with superoxide dismutase (SOD) and catalase (CAT), responses of enzymatic components--ascorbate peroxidase (APX), monodehydroascorbate reductase (MDAR), glutathione reductase (GR) and non-enzymatic redox components of ascorbate-glutathione (Asc-GSH) cycle, which play a significant role in scavenging cellular ROS, were examined in the presence of mitochondrial inhibitors.

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Plant respiration is characterized by two pathways for electron transfer to O(2), namely the cytochrome pathway (CP) that is linked to ATP production, and the alternative pathway (AP), where electrons from ubiquinol are directly transferred to O(2) via an alternative oxidase (AOX) without concomitant ATP production. This latter pathway is well suited to dispose of excess electrons in the light, leading to optimized photosynthetic performance. We have characterized T-DNA-insertion mutant lines of Arabidopsis thaliana that do not express the major isoform, AOX1A.

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Chloroplasts and mitochondria are traditionally considered to be autonomous organelles but they are not as independent as they were once thought to be. Mitochondrial metabolism, particularly the bioenergetic reactions of oxidative electron transport and phosphorylation, continue to be active in the light and are essential for sustaining photosynthetic carbon assimilation. The marked and mutually beneficial interaction between mitochondria and chloroplasts is intriguing.

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