Publications by authors named "Jagat K Roy"

12 Publications

  • Page 1 of 1

Developmental expression, co-localization and genetic interaction of exocyst component Sec15 with Rab11 during Drosophila development.

Exp Cell Res 2019 08 7;381(1):94-104. Epub 2019 May 7.

Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221 005, India.

Sec15, a component of an evolutionarily conserved octomeric exocyst complex, has been identified as an interactor of GTP-bound Rab11 in mammals and Drosophila which shows its role in secretion in yeast and intracellular vesicle transport. Here, we report the expression patterns of Drosophila Sec15 (DSec15) transcript and Sec15 protein during Drosophila development. At early embryonic stages, a profound level of maternally loaded DSec15 transcript and protein is found. At cellular blastoderm cells (stage 5 embryos); the expression is seen in pole cells, apical membrane and sub-apical region. The transcript is predominantly accumulated in mesoderm, tracheal pits, gut, LE cells, trachea, and ventral nerve cord as development proceeds. While, a robust expression of Sec15 is seen in amnioserosa (AS), lateral epidermis (LAE), developing trachea, gut, ventral nerve cord and epithelial cells. During larval development, the transcript is also found in all imaginal discs with a distinguished accumulation in the morphogenetic furrow of eye disc, gut, proventriculus and gastric ceacae, garland cells/nephrocytes, malpighian tubules, ovary and testis. Further, we show that Sec15 co-localizes with Rab11 during Drosophila embryonic and larval development. Finally, using a genetic approach, we demonstrate that Sec15 interacts with Rab11 in producing blister during Drosophila wing development.
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http://dx.doi.org/10.1016/j.yexcr.2019.04.038DOI Listing
August 2019

Curcumin Quantum Dots Mediated Degradation of Bacterial Biofilms.

Front Microbiol 2017 9;8:1517. Epub 2017 Aug 9.

Molecular Immunology Laboratory, Department of Biochemistry, Institute of Science, Banaras Hindu UniversityVaranasi, India.

Bacterial biofilm has been reported to be associated with more than 80% of bacterial infections. Curcumin, a hydrophobic polyphenol compound, has anti-quorum sensing activity apart from having antimicrobial action. However, its use is limited by its poor aqueous solubility and rapid degradation. In this study, we attempted to prepare quantum dots of the drug curcumin in order to achieve enhanced solubility and stability and investigated for its antimicrobial and antibiofilm activity. We utilized a newer two-step bottom up wet milling approach to prepare Curcumin Quantum Dots (CurQDs) using acetone as a primary solvent. Minimum inhibitory concentration against select Gram-positive and Gram-negative bacteria was performed. The antibiofilm assay was performed at first using 96-well tissue culture plate and subsequently validated by Confocal Laser Scanning Microscopy. Further, biofilm matrix protein was isolated using formaldehyde sludge and TCA/Acetone precipitation method. Protein extracted was incubated with varying concentration of CurQDs for 4 h and was subjected to SDS-PAGE. Molecular docking study was performed to observe interaction between curcumin and phenol soluble modulins as well as curli proteins. The biophysical evidences obtained from TEM, SEM, UV-VIS, fluorescence, Raman spectroscopy, and zeta potential analysis confirmed the formation of curcumin quantum dots with increased stability and solubility. The MICs of curcumin quantum dots, as observed against both select gram positive and negative bacterial isolates, was observed to be significantly lower than native curcumin particles. On TCP assay, Curcumin observed to be having antibiofilm as well as biofilm degrading activity. Results of SDS-PAGE and molecular docking have shown interaction between biofilm matrix proteins and curcumin. The results indicate that aqueous solubility and stability of Curcumin can be achieved by preparing its quantum dots. The study also demonstrates that by sizing down the particle size has not only enhanced its antimicrobial properties but it has also shown its antibiofilm activities. Further, study is needed to elucidate the exact nature of interaction between curcumin and biofilm matrix proteins.
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http://dx.doi.org/10.3389/fmicb.2017.01517DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5552728PMC
August 2017

Study of bantam miRNA expression in brain tumour resulted due to loss of polarity modules in Drosophila melanogaster.

J Genet 2017 Jun;96(2):365-369

Banaras Hindu University, Varanasi 221 005, India.

Disturbance of delicate concordance between stem cell proliferation, specification and differentiation during brain development leads to several neural disorders including tumours. Accumulating evidences have demonstrated involvement of short noncoding microRNAs (miRNAs) in governing several biological as well as pathological processes, including tumourigenesis across various species. Drosophila bantam miRNA, known to regulate critical physiological functions is reported to have elevated expression in ovarian tumour. Here, we provide an update on the expression of bantam miRNA in Drosophila brain tumour background resulting due to loss of well characterized polarity proteins, Brat, Lgl and Scrib. Since, both miRNA TaqMan assay and bantam sensor assay showed elevated expression of bantam in brain tumour background, it clearly reflects presence of an antagonistic relationship between polarity proteins and bantam miRNA indicating of its involvement in tumour progression.
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http://dx.doi.org/10.1007/s12041-017-0782-yDOI Listing
June 2017

Distribution of HPV Genotypes and Involvement of Risk Factors in Cervical Lesions and Invasive Cervical Cancer: A Study in an Indian Population.

Int J Mol Cell Med 2014 ;3(2):61-73

Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221005, India.

Human papilloma virus (HPV) is considered as the main sexually transmitted etiological agent for the cause and progression of preneoplastic cervical lesions to cervical cancer. This study is discussing the prevalence of HPV and its genotypes in cervical lesions and invasive cervical cancer tissues and their association with various risk factors in women from Varanasi and its adjoining areas in India. A total of 122 cervical biopsy samples were collected from SS Hospital and Indian Railways Cancer Institute and Research Centre, Varanasi and were screened for HPV infection by PCR using primers from L1 consensus region of the viral genome. HPV positive samples were genotyped by type-specific PCR and sequencing. The association of different risk factors with HPV infection in various grades of cervical lesion was evaluated by chi-square test. A total of 10 different HPV genotypes were observed in women with cervicitis, CIN, invasive squamous cell cervical carcinoma and adenocarcinoma. Increased frequency of HPV infection with increasing lesion grade (p=0.002) was observed. HPV16 being the predominant type was found significantly associated with severity of the disease (p=0.03). Various socio- demographic factors other than HPV including high parity (p<0.0001), rural residential area (p<0.0001), elder age (p<0.0001), low socio-economic status (p<0.0001) and women in postmenopausal group (p<0.0001) were also observed to be associated with cervical cancer.These findings show HPV as a direct cause of cervical cancer suggesting urgent need of screening programs and HPV vaccination in women with low socio-economic status and those residing in rural areas.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4082807PMC
July 2014

Rab11 is required for cell adhesion, maintenance of cell shape and actin-cytoskeleton organization during Drosophila wing development.

Int J Dev Biol 2011 ;55(3):269-79

Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, India.

Intracellular protein trafficking is a key factor in maintaining epithelial cell adhesion and cell shape. Small monomeric Rab GTPases are key players involved in intracellular membrane transport. Rab11, a subfamily of the Ypt/Rab gene family of ubiquitously expressed GTPases, is associated with recycling endosomes, and acts as a master molecule in regulating vesicular trafficking. Wing epithelium of Drosophila has been chosen to address the involvement of Rab11 in trafficking of a cell adhesion molecule, the βPS integrin. Here, we show that Rab11 immunocolocalizes with trans-Golgi network and it is enriched in the centrosomal/recycling endosomal area labeled by γ-Tubulin. Furthermore, Rab11 is required for transcytic and exocytic trafficking of βPS integrin; alterations of Rab11 function by different genetic procedures in wings results in the formation of blisters. We show altered activity of Rab11 affects cell adhesion, cell shape and organization in the actin-cytoskeleton during wing morphogenesis. Finally, using a genetic approach, we demonstrate that Rab11 interacts with the βPS integrin. Collectively, our data suggest that Rab11 regulates cell adhesion, maintenance of cell shape and actin-cytoskeleton organization during Drosophila wing development.
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http://dx.doi.org/10.1387/ijdb.103149tbDOI Listing
December 2011

Rab11 regulates JNK and Raf/MAPK-ERK signalling pathways during Drosophila wing development.

Cell Biol Int 2010 Nov;34(11):1113-8

Department of Zoology, Banaras Hindu University, Varanasi, India.

Developmental signalling pathways are regulated by intracellular vesicle trafficking in multicellular organisms. In our earlier communication, we have shown that mutation in Rab11 (a subfamily of the Ypt/Rab gene family) results in the activation of JNK signalling pathways in Drosophila eye. Here, we report that Rab11 regulates JNK and Raf/MAPK-ERK signalling pathways during Drosophila wing development. Using immunofluorescence and immunohistochemical analyses, we show that overexpression of Rab11 in mutant wing imaginal disc cells triggers the induction of apoptosis and activation of JNK and ERK. Further, using a genetic approach it has been shown that Rab11 interacts with the components of these pathways during Drosophila wing development. In addition to this, in Rab11 mutant wing imaginal discs JNK activity was monitored using puc(E)⁶⁹, a P-lacZ enhancer-trap line inserted in puckered (puc). A strong induction of puc in Rab11 mutant wing imaginal disc cells provided a strong support that Rab11 regulates the JNK signalling pathway during Drosophila wing development.
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http://dx.doi.org/10.1042/CBI20100155DOI Listing
November 2010

Nanoparticle-induced controlled biodegradation and its mechanism in poly(epsilon-caprolactone).

ACS Appl Mater Interfaces 2010 Jan;2(1):69-81

School of Materials Science and Technology, Institute of Technology, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India.

Poly(epsilon-caprolactone) (PCL)/layered silicate nanocomposites have been prepared via solution route. Two different organically modified nanoclays were used to compare the variation in properties based on organic modifications. The nanostructures, as observed from wide-angle X-ray diffraction and transmission electron microscopy, indicate intercalated and partially exfoliated hybrids depending on the nature of organic modification in nanoclay. The nanohybrids exhibit significant improvement in thermal and mechanical properties of the matrix as compared to neat polymer. The nanoclays act as nucleating agent for the crystallization of PCL. The biodegradability of pure PCL and its nanocomposites have been studied under controlled conditions in enzyme, pure microorganism (fungi), compost, Ganges water, and alkaline buffer solution. The rate of biodegradation of PCL has enhanced dramatically in nanohybrids and depends strongly on the media used. Scanning confocal, electron, and atomic force microscopes have used to demarcate the nature of biodegradation of pristine PCL and its nanocomposites. The change in biodegradation is rationalized in terms of the crystallization behavior and organic modification in nanoclays of the nanohybrids vis-a-vis the neat polymer. The extent of compatibility was measured quantitatively through the interaction parameter for two different nanoclays to compare and establish the reason for variation in their properties in nanohybrids. A biodegradation mechanism has been revealed for PCL and its nanocomposites through enzyme activity in varying pH environment.
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http://dx.doi.org/10.1021/am900584rDOI Listing
January 2010

Mutation in Rab11 results in abnormal organization of ommatidial cells and activation of JNK signaling in the Drosophila eye.

Eur J Cell Biol 2009 Aug 26;88(8):445-60. Epub 2009 May 26.

Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221005, India.

Rab11(mo), a P insertion line of Rab11 showed degenerated ommatidia and excess cell death in larval/pupal eyes. Here, we demonstrate that Rab11 is essential for normal organization of ommatidial cells and their survival in Drosophila, and a mutation in this gene results in cytoskeleton disruption and activation of JNK signaling in the eye. The spatial organization of various cell types in compound eye, viz., cone, photoreceptor, pigment and bristle cells, were disrupted in Rab11 mutants as revealed by immunostaining of F-actin and adherens and septate junction proteins. Genetic interaction studies indicated that mutation in Rab11 upregulates Drosophila apoptotic genes, rpr, hid and grim. In order to study the pathway that causes excessive cell death in Rab11 mutants, the JNK pathway was chosen and genetic interaction analyses were carried out between Rab11 and candidates of the JNK signaling pathway. A downregulation of JNK signaling rescued the phenotype in Rab11 mutant eyes significantly while overexpression of JNK in the eyes using UAS-eiger, UAS-dtak1 or EP(2)0578, resulted in enhancement of the eye phenotype indicating a link between Rab11 and the JNK signaling pathway.
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http://dx.doi.org/10.1016/j.ejcb.2009.02.188DOI Listing
August 2009

Rab11 is required for myoblast fusion in Drosophila.

Cell Tissue Res 2009 Jun 16;336(3):489-99. Epub 2009 Apr 16.

Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221 005, India.

Rab11, an evolutionarily conserved, ubiquitously expressed subfamily of small monomeric Rab GTPases, has been implicated in regulating vesicular trafficking through the recycling of endosomal compartment. In order to gain an insight into the role of this gene in myogenesis during embryonic development, we have studied the expression pattern of Rab11 in mesoderm during muscle differentiation in Drosophila embryo. When dominant-negative or constitutively active Drosophila Rab11 proteins are expressed or Rab11 is reduced via double-stranded RNA in muscle precursors, they cause partial failure of myoblast fusion and show anomalies in the shape of the muscle fibres. Our results suggest that Rab11 plays no role in cell fate specification in muscle precursors but is required late in the process of myoblast fusion.
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http://dx.doi.org/10.1007/s00441-009-0782-1DOI Listing
June 2009

Rab11 is required for embryonic nervous system development in Drosophila.

Cell Tissue Res 2009 Feb 18;335(2):349-56. Epub 2008 Nov 18.

Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India.

In eukaryotes, membrane trafficking is regulated by the small monomeric GTPases of Rab protein family. Rab11, an evolutionary conserved, ubiquitously expressed subfamily of the Rab GTPases, has been implicated in the regulation of vesicular trafficking through the recycling of endosomes. To dissect out the role of this protein during embryonic nervous system development, we have studied the expression pattern of Rab11 in the ventral nerve cord during neuronal differentiation in the Drosophila embryo. When the dominant-negative or constitutively-active mutant DRab11 proteins are expressed in neurons, or when homozygous mutant Rab11 embryos are analyzed, defects are found in the developing central nervous system, along with disorganization and misrouting of embryonic axons. Our results provide the first in vivo evidence that Rab11 is involved in the development of the nervous system during Drosophila embryogenesis.
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http://dx.doi.org/10.1007/s00441-008-0711-8DOI Listing
February 2009

Rab11 is essential for fertility in Drosophila.

Cell Biol Int 2008 Sep 10;32(9):1158-68. Epub 2008 Apr 10.

Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221 005, Uttar Pradesh, India.

Rab11, a small GTP binding protein involved in vesicular trafficking, has emerged as a key player in regulating various cellular events during Drosophila development and differentiation. In our earlier study a P-insertion line, Rab11mo, was established as a new hypomorphic allele of Rab11 gene, showing degenerated eye phenotype, bristle abnormalities and sterility. We show here that Rab11 is expressed in the entire testis, more prominently in the secretory cells, and in ovary it is localized at the posterior pole. Rab11mo males and females are sterile. The sterility in males has been attributed to defects in the sperm individualization process, while in females, cytoskeleton disruption and reduction/loss of the posteriorly localized protein, Vasa, as a consequence of loss/mislocalization of Rab11 might be the cause of sterility. Fertility as well as the posterior localization of Rab11 and Vasa or cytoskeleton integrity was restored in pCaSpeR4-Rab11/+; Rab11mo/Rab11mo egg chambers, confirming the requirement of Rab11 in these events.
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http://dx.doi.org/10.1016/j.cellbi.2008.04.002DOI Listing
September 2008

Rab11 is required during Drosophila eye development.

Int J Dev Biol 2005 ;49(7):873-9

Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, India.

In an effort to identify the role of Rab11, a small GTP binding protein, during Drosophila differentiation, phenotypic manifestations associated with different alleles of Rab11 were studied. The phenotypes ranged from eye-defects, bristle abnormalities and sterility to lethality during various developmental stages. In this paper, our focus is targeted on eye defects caused by Rab11 mutations. A novel P-element insertion in the Rab11 locus, Rab11mo, displayed characteristic retinal anomalies, which could be reverted by P-element excision and expression of Rab11+ transgenes. During larval development, Rab11 is widely synthesized in photoreceptor cells and localizes to the rhabdomeres and lamina neuropil in adult eyes. Photoreceptors and associated bristles failed to be formed in homozygous clones generated in Rab11EP(3)3017 eyes. Decreased levels of Rab11 protein and increased cell death in Rab11mo third-instar larval eye-antennal discs suggest that the retinal defects originate during larval development. Our data indicate a requirement for Rab11 in ommatidial differentiation during Drosophila eye development.
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http://dx.doi.org/10.1387/ijdb.051986daDOI Listing
January 2006