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991.
Paul G. Becher Arne Hagman Vasiliki Verschut Amrita Chakraborty Elżbieta Rozpędowska Sébastien Lebreton Marie Bengtsson Gerhard Flick Peter Witzgall Jure Piškur 《Ecology and evolution》2018,8(5):2962-2974
Yeast volatiles attract insects, which apparently is of mutual benefit, for both yeasts and insects. However, it is unknown whether biosynthesis of metabolites that attract insects is a basic and general trait, or if it is specific for yeasts that live in close association with insects. Our goal was to study chemical insect attractants produced by yeasts that span more than 250 million years of evolutionary history and vastly differ in their metabolism and lifestyle. We bioassayed attraction of the vinegar fly Drosophila melanogaster to odors of phylogenetically and ecologically distinct yeasts grown under controlled conditions. Baker's yeast Saccharomyces cerevisiae, the insect‐associated species Candida californica, Pichia kluyveri and Metschnikowia andauensis, wine yeast Dekkera bruxellensis, milk yeast Kluyveromyces lactis, the vertebrate pathogens Candida albicans and Candida glabrata, and oleophilic Yarrowia lipolytica were screened for fly attraction in a wind tunnel. Yeast headspace was chemically analyzed, and co‐occurrence of insect attractants in yeasts and flowering plants was investigated through a database search. In yeasts with known genomes, we investigated the occurrence of genes involved in the synthesis of key aroma compounds. Flies were attracted to all nine yeasts studied. The behavioral response to baker's yeast was independent of its growth stage. In addition to Drosophila, we tested the basal hexapod Folsomia candida (Collembola) in a Y‐tube assay to the most ancient yeast, Y. lipolytica, which proved that early yeast signals also function on clades older than neopteran insects. Behavioral and chemical data and a search for selected genes of volatile metabolites underline that biosynthesis of chemical signals is found throughout the yeast clade and has been conserved during the evolution of yeast lifestyles. Literature and database reviews corroborate that yeast signals mediate mutualistic interactions between insects and yeasts. Moreover, volatiles emitted by yeasts are commonly found also in flowers and attract many insect species. The collective evidence suggests that the release of volatile signals by yeasts is a widespread and phylogenetically ancient trait, and that insect–yeast communication evolved prior to the emergence of flowering plants. Co‐occurrence of the same attractant signals in yeast and flowers suggests that yeast‐insect communication may have contributed to the evolution of insect‐mediated pollination in flowers. 相似文献
992.
993.
Shruti Chakraborty Sayak Ganguli Aritra Chowdhury Michael Ibba Rajat Banerjee 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(8):1801-1809
Background
Under oxidative stress cytoplasmic aminoacyl-tRNA synthetase (aaRSs) substrate specificity can be compromised, leading to tRNA mischarging and mistranslation of the proteome. Whether similar processes occur in mitochondria, which are major cellular sources of reactive oxygen species (ROS), is unknown. However, relaxed substrate specificity in yeast mitochondrial phenylalanyl-tRNA synthetase (ScmitPheRS) has been reported to increase tRNA mischarging and blocks mitochondrial biogenesis.Methods
Non-reducing denaturing PAGE, cysteine reactivity studies, MALDI-TOF mass spectrometry, enzyme assay, western blot, growth assay, circular dichroism, dynamic light scattering and fluorescence spectroscopy were used to study the effect of oxidative stress on ScmitPheRS activity.Results
ScmitPheRS is reversibly inactivated under oxidative stress. The targets for oxidative inactivation are two conserved cysteine residues resulting in reversible intra-molecular disulfide bridge formation. Replacement of either conserved cysteine residue increased viability during growth under oxidative stress.Conclusion
Formation of intra-molecular disulfide bridge under oxidative stress hinders the tRNAPhe binding of the enzyme, thus inactivating ScmitPheRS reversibly.General significance
The ScmitPheRS activity is compromised under oxidative stress due to formation of intra-molecular disulfide bridge. The sensitivity of ScmitPheRS to oxidation may provide a protective mechanism against error-prone translation under oxidative stress. 相似文献994.
995.
Ujjal Das Krishnendu Manna Mahuya Sinha Sanjukta Datta Dipesh Kr Das Anindita Chakraborty Mahua Ghosh Krishna Das Saha Sanjit Dey 《PloS one》2014,9(5)
Ionizing radiation is responsible for oxidative stress by generating reactive oxygen species (ROS), which alters the cellular redox potential. This change activates several redox sensitive enzymes which are crucial in activating signaling pathways at molecular level and can lead to oxidative stress induced inflammation. Therefore, the present study was intended to assess the anti-inflammatory role of ferulic acid (FA), a plant flavonoid, against radiation-induced oxidative stress with a novel mechanistic viewpoint. FA was administered (50 mg/kg body wt) to Swiss albino mice for five consecutive days prior to exposing them to a single dose of 10 Gy 60Co γ-irradiation. The dose of FA was optimized from the survival experiment and 50 mg/kg body wt dose showed optimum effect. FA significantly ameliorated the radiation induced inflammatory response such as phosphorylation of IKKα/β and IκBα and consequent nuclear translocation of nuclear factor kappa B (NF-κB). FA also prevented the increase of cycloxygenase-2 (Cox-2) protein, inducible nitric oxide synthase-2 (iNOS-2) gene expression, lipid peroxidation in liver and the increase of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in serum. It was observed that exposure to radiation results in decreased activity of superoxide dismutase (SOD), catalase (CAT) and the pool of reduced glutathione (GSH) content. However, FA treatment prior to irradiation increased the activities of the same endogenous antioxidants. Thus, pretreatment with FA offers protection against gamma radiation induced inflammation. 相似文献
996.
Pradeep Kota Ginka Buchner Hirak Chakraborty Yan L. Dang Hong He Guilherme J. M. Garcia Jan Kubelka Martina Gentzsch M. Jackson Stutts Nikolay V. Dokholyan 《The Journal of biological chemistry》2014,289(33):23029-23042
The epithelial sodium channel (ENaC) is activated upon endoproteolytic cleavage of specific segments in the extracellular domains of the α- and γ-subunits. Cleavage is accomplished by intracellular proteases prior to membrane insertion and by surface-expressed or extracellular soluble proteases once ENaC resides at the cell surface. These cleavage events are partially regulated by intracellular signaling through an unknown allosteric mechanism. Here, using a combination of computational and experimental techniques, we show that the intracellular N terminus of γ-ENaC undergoes secondary structural transitions upon interaction with phosphoinositides. From ab initio folding simulations of the N termini in the presence and absence of phosphatidylinositol 4,5-bisphosphate (PIP2), we found that PIP2 increases α-helical propensity in the N terminus of γ-ENaC. Electrophysiology and mutation experiments revealed that a highly conserved cluster of lysines in the γ-ENaC N terminus regulates accessibility of extracellular cleavage sites in γ-ENaC. We also show that conditions that decrease PIP2 or enhance ubiquitination sharply limit access of the γ-ENaC extracellular domain to proteases. Further, the efficiency of allosteric control of ENaC proteolysis is dependent on Tyr370 in γ-ENaC. Our findings provide an allosteric mechanism for ENaC activation regulated by the N termini and sheds light on a potential general mechanism of channel and receptor activation. 相似文献
997.
Arindam Chakraborty 《Cell cycle (Georgetown, Tex.)》2014,13(11):1663-1670
Heterochromatin protein 1α (HP1α), a bona fide factor of silent chromatin, is required for establishing as well as maintaining the higher-order chromatin structure in eukaryotes. HP1α is decorated with several post-translational modifications, and many of these are critical for its cellular functions. HP1α is heavily phosphorylated; however, its physiological relevance had remained to be completely understood. We have recently demonstrated that human HP1α is a mitotic target for NDR kinase, and the phosphorylation at the hinge region of HP1α at the G2/M phase of the cell cycle is crucial for mitotic progression and Sgo1 loading at mitotic centromeres (Chakraborty et al., 2014). We now demonstrate that the dephosphorylation of HP1α within its hinge domain occurs during mitosis, specifically soon after prometaphase. In the absence of the hinge-specific HP1α phosphorylation, either as a consequence of depleting NDR1 or in cells expressing a non-phosphorylatable HP1α mutant, the cells arrest in prometaphase with several mitotic defects. In this study we show that NDR1-depleted cells expressing hinge-specific phosphomimetic HP1α mutant rescues the prometaphase arrest but displays defects in mitotic exit, suggesting that the dephosphorylation of HP1α is required for the completion of cytokinesis. Taken together, our results reveal that the phosphorylation–dephosphorylation cycle of HP1α orchestrates accurate progression of cells through mitosis. 相似文献
998.
Mallinath Chakraborty Eamon P. McGreal Andrew Williams Philip L. Davies Wendy Powell Salima Abdulla Nikolai N. Voitenok John Hogwood Elaine Gray Brad Spiller Rachel C. Chambers Sailesh Kotecha 《PloS one》2014,9(12)
Rationale
The chemokine interleukin-8 is implicated in the development of bronchopulmonary dysplasia in preterm infants. The 77-amino acid isoform of interleukin-8 (interleukin-877) is a less potent chemoattractant than other shorter isoforms. Although interleukin-877 is abundant in the preterm circulation, its regulation in the preterm lung is unknown.Objectives
To study expression and processing of pulmonary interleukin-877 in preterm infants who did and did not develop bronchopulmonary dysplasia.Methods
Total interleukin-8 and interleukin-877 were measured in bronchoalveolar lavage fluid from preterm infants by immunoassay. Neutrophil serine proteases were used to assess processing. Neutrophil chemotaxis assays and degranulation of neutrophil matrix metalloproteinase-9 were used to assess interleukin-8 function.Main Results
Peak total interleukin-8 and interleukin-877 concentrations were increased in infants who developed bronchopulmonary dysplasia compared to those who did not. Shorter forms of interleukin-8 predominated in the preterm lung (96.3% No-bronchopulmonary dysplasia vs 97.1% bronchopulmonary dysplasia, p>0.05). Preterm bronchoalveolar lavage fluid significantly converted exogenously added interleukin-877 to shorter isoforms (p<0.001). Conversion was greater in bronchopulmonary dysplasia infants (p<0.05). This conversion was inhibited by α-1 antitrypsin and antithrombin III (p<0.01). Purified neutrophil serine proteases efficiently converted interleukin-877 to shorter isoforms in a time- and dose-dependent fashion; shorter interleukin-8 isoforms were primarily responsible for neutrophil chemotaxis (p<0.001). Conversion by proteinase-3 resulted in significantly increased interleukin-8 activity in vitro (p<0.01).Conclusions
Shorter, potent, isoforms interleukin-8 predominate in the preterm lung, and are increased in infants developing bronchopulmonary dysplasia, due to conversion of interleukin-877 by neutrophil serine proteases and thrombin. Processing of interleukin-8 provides an attractive therapeutic target to prevent development of bronchopulmonary dysplasia. 相似文献999.
Durbba Nath Himangshu Deka Arif Uddin Supriyo Chakraborty 《Journal of cellular biochemistry》2019,120(5):7649-7656
Chronic obstructive pulmonary disease (COPD), a lung disease, affects a large number of people worldwide, leading to death. Here, we analyzed the compositional features and trends of codon usage of the genes influencing COPD to understand molecular biology, genetics, and evolutionary relationships of these genes as no work was reported yet. Coding sequences of COPD genes were found to be rich in guanine-cytosine (GC) content. A high value (34-60) of the effective number of codons of the genes indicated low codon usage bias (CUB). Correspondence analysis suggested that the COPD genes were distinct in their codon usage patterns. Relative synonymous codon usage values of codons differed between the more preferred codons and the less-preferred ones. Correlation analysis between overall nucleotides and those at third codon position revealed that mutation pressure might influence the CUB of the genes. The high correlation between GC12 and GC3 signified that directional mutation pressure might have operated at all the three codon positions in COPD genes. 相似文献
1000.
Rapid Identification and Typing of Listeria Species by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry 总被引:1,自引:0,他引:1 下载免费PDF全文
Sukhadeo B. Barbuddhe Thomas Maier Gerold Schwarz Markus Kostrzewa Herbert Hof Eugen Domann Trinad Chakraborty Torsten Hain 《Applied microbiology》2008,74(17):5402-5407
Listeria monocytogenes is a food-borne pathogen that is the causative agent of human listeriosis, an opportunistic infection that primarily infects pregnant women and immunologically compromised individuals. Rapid, accurate discrimination between Listeria strains is essential for appropriate therapeutic management and timely intervention for infection control. A rapid method involving matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) that shows promise for identification of Listeria species and typing and even allows for differentiation at the level of clonal lineages among pathogenic strains of L. monocytogenes is presented. A total of 146 strains of different Listeria species and serotypes as well as clinical isolates were analyzed. The method was compared with the pulsed-field gel electrophoresis analysis of 48 Listeria strains comprising L. monocytogenes strains isolated from food-borne epidemics and sporadic cases, isolates representing different serotypes, and a number of Listeria strains whose genomes have been completely sequenced. Following a short inactivation/extraction procedure, cell material from a bacterial colony was deposited on a sample target, dried, overlaid with a matrix necessary for the MALDI process, and analyzed by MALDI-TOF MS. This technique examines the chemistry of major proteins, yielding profile spectra consisting of a series of peaks, a characteristic “fingerprint” mainly derived from ribosomal proteins. Specimens can be prepared in a few minutes from plate or liquid cultures, and a spectrum can be obtained within 1 minute. Mass spectra derived from Listeria isolates showed characteristic peaks, conserved at both the species and lineage levels. MALDI-TOF MS fingerprinting may have potential for Listeria identification and subtyping and may improve infection control measures. 相似文献