Browsing by Author "Dutta-Gupta, Aparna"

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Cloning and characterization of a riboflavin-binding hexamerin from the larval fat body of a lepidopteran stored grain pest, Corcyra cephalonica
(Elsevier Inc., 2016) Rao, V. Venkat; Ningshen, Thuirei Jacob; Chaitanya, R. K.; Senthilkumaran, B.; Dutta-Gupta, Aparna; Rao, V.V.; Ningshen, T.J.; Chaitanya, R.K.; Senthilkumaran, B.; Dutta-Gupta, A.
In the present study, a riboflavin-binding hexamerin (RbHex) was cloned and characterized from the larval fat body of Corcyra cephalonica. The complete cDNA (2121 bp) encodes a 706-amino acid protein with a molecular mass ~ 82 kDa. Expression of RbHex 82 was predominant in fat body among larval tissues. Further, it is prominently expressed during the last instar larval development. Homology modeling and docking studies predicted riboflavin binding site of the hexamerin. Spectrofluorimetric analysis further confirmed riboflavin release from the hexamerin fraction. Quantitative RT-PCR studies demonstrated hormonal regulation of RbHex 82. 20-Hydroxyecdysone (20HE) had a stimulatory effect on its transcription whereas JH alone did not show any effect. However, JH in the presence of 20HE maintains the RbHex 82 expression which indicates the JH's role as a status quo factor. This study is the first to report the characterization of riboflavin-binding hexamerin in a lepidopteran pest. Further, the possibility of RbHex 82 as a pest control target is discussed. ? 2016 Elsevier Inc.
Fat body remodeling in Spodoptera litura F. (Lepidoptera: Noctuidae) during postembryonic development2017
(Association for Advancement of Entomology, 2017) Chauhan, Vinod K.; Dhania, Narendra K.; Ayinampudi, Pavani; Chaitanya, R. K.; Dutta-Gupta, Aparna
During insect metamorphosis, larval structures including fat body are replaced by the adult ones. This process involves lysosomal enzyme-mediated remodeling of fat body. The objective of this study is to characterize the events leading to fat body remodeling during postembryonic development in an important agricultural pest, Spodoptera litura. Present study showed that the fat body undergoes significant changes in its morphology as well as histology. During the larval stage the tissue is primarily synthetic and secretory in nature and releases large amount of macromolecules including hexamerins in the heamolyph. While at pre-pupal and pupal stages it acts as a storage tissue and accumulates number of protein granules. Radiolabelling and DNA analysis studies revealed higher content of DNA in the larval fat body. The decline seen in pre-pupae corroborated well with disintegration of nuclei which were remodeled during pupal and adult stages. Further, the role of an insect morphogenetic hormone, 20-hydroxyecdysone (20E) in fat body reorganization has also been elucidated. This study enables us to understand the basic mechanism and altered micro-environment of the dynamic fat body tissue during larval-pupal-adult transition and metamorphosis.
Gut-specific arylphorin mediates midgut regenerative response against Cry-induced damage in Achaea janata
(Elsevier Inc., 2021-04-13T00:00:00) Dhania, Narender K.; Chauhan, Vinod K.; Abhilash, Dasari; Thakur, Vivek; Chaitanya, R.K.; Dutta-Gupta, Shourya; Dutta-Gupta, Aparna
Development of insect resistance to biopesticides is a current and pertinent global issue. Earlier, it was established that lepidopteran larvae can recover from Bt intoxication via a midgut regenerative response and subsequently generate resistance. Molecular aspects of restoration of the midgut integrity following toxin exposure are emerging recently. In the present study, we bring out the pivotal role of gut arylphorin in mediating the midgut regenerative response following sublethal Bt exposure in Achaea janata. Bt-induced midgut damage was characterized by microscopic analysis using differential interference contrast (DIC) and immunofluorescence (IF). Extensive disruption of brush-border membrane, associated with the underlying cytoskeletal alterations including F-actin, ?-actin and ?-tubulin was observed. Single-photon fluorescence microscopy combined with fluorescence lifetime imaging (FLIM) established the metabolic state associated with enhanced stem cell proliferation and migration from the basal side towards the luminal side following the damage. In-silico analysis revealed the phylogenetic relationship of gut arylphorin with closely related insect species and indicated the presence of two different subunits. Transient RNAi knockdown of the arylphorin resulted in diminished expression of mitotic Cyclin B mRNA levels. Human monoclonal Cyclin B antibody cross-reactivity with the Cyclin B located in the stem cells further validate the role of arylphorin as the mitogenic factor responsible for stem cell proliferation and epithelial regeneration. An in-depth understanding of resistance mechanisms will aid in the design of new strategies for the long-term usage and efficacy of Bt technology against pest control. � 2021
Larval mid-gut responses to sub-lethal dose of cry toxin in lepidopteran pest Achaea janata
(Frontiers Media S.A., 2017) Chauhan, Vinod K.; Dhania, Narendra K.; Chaitanya, R. K.; Senthilkumaran, Balasubramanian; Dutta-Gupta, Aparna; Chauhan, V.K.; Dhania, N.K.; Chaitanya, R.K.; Senthilkumaran, B.; Dutta-Gupta, A.
The lack of homogeneity in field application of Bacillus thuringiensis formulation often results in ingestion of sub-lethal doses of the biopesticide by a fraction of pest population and there by promotes the toxin tolerance and resistance in long term. Gut regeneration seems to be one of the possible mechanism by which this is accomplished. However, the existing information is primarily derived from in vitro studies using mid-gut cell cultures. Present study illustrates cellular and molecular changes in mid-gut epithelium of a Bt-susceptible polyphagous insect pest castor semilooper, Achaea janata in response to a Cry toxin formulation. The present report showed that prolonged exposure to sub-lethal doses of Cry toxin formulation has deleterious effect on larval growth and development. Histological analysis of mid-gut tissue exhibits epithelial cell degeneration, which is due to necrotic form of cell death followed by regeneration through enhanced proliferation of mid-gut stem cells. Cell death is demonstrated by confocal microscopy, flow-cytometry, and DNA fragmentation analysis. Cell proliferation in control vs. toxin-exposed larvae is evaluated by bromodeoxyuridine (BrdU) labeling and toluidine blue staining. Intriguingly, in situ mRNA analysis detected the presence of arylphorin transcripts in larval mid-gut epithelial cells. Quantitative PCR analysis further demonstrates altered expression of arylphorin gene in toxin-exposed larvae when compared with the control. The coincidence of enhanced mid-gut cell proliferation coincides with the elevated arylphorin expression upon Cry intoxication suggests that it might play a role in the regeneration of mid-gut epithelial cells. ? 2017 Chauhan, Dhania, Chaitanya, Senthilkumaran and Dutta-Gupta. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).
Midgut aminopeptidase N expression profile in castor semilooper (Achaea janata) during sublethal Cry toxin exposure
(Springer, 2021-03-19T00:00:00) Chauhan, Vinod K.; Dhania, Narender K.; Lokya, Vadthya; Bhuvanachandra, Bhoopal; Padmasree, Kollipara; Dutta-Gupta, Aparna
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 Bacillus thuringiensis (Bt). In the present study, aminopeptidase N (APN) was characterized as Cry-toxin-interacting protein in the larval midgut of castor semilooper, Achaea janata. Transcriptomic and proteomic analyses revealed the presence of multiple isoforms of APNs (APN1, 2, 4, 6 and 9) which have less than 40% sequence similarity but show the presence of characteristic �GAMENEG� and zinc-binding motifs. Feeding a sublethal dose of Cry toxin caused differential expression of various APN isoform. Further, 6th-generation Cry-toxin-exposed larvae showed reduced expression of APN2. This report suggests that A. janata larvae exploit altered expression of APNs to overcome the deleterious effects of Cry toxicity, which might facilitate toxin tolerance in the long run. � 2021, Indian Academy of Sciences.