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1.
Int J Biometeorol ; 68(4): 749-760, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38244115

RESUMO

Changing climate exerts significant pressure on coastal wetland fishery, ecosystems and livelihood at the eco-regional level. In the present study, an indicator and scoring-based vulnerability assessment framework was developed to assess climate change-induced potential impacts and vulnerability of the coastal wetlands through stakeholder perception and primary data collection on ecology and fisheries. The study was conducted in 12 coastal wetlands in the Gangetic estuarine regions of eastern India. Analysis of rainfall, temperature and extreme climatic events was also carried out. The climate variability in the region was analysed and discussed in the context of ecosystem health and sustainability indicators. The results indicated that anthropogenic stress has a greater influence on ecosystem services than climatic stress. However, the nature and degree of vulnerability of fishers to climate change vary with their capacity to adapt to such changes and alternate sources of livelihood. Altogether, 34 fish species were documented, belonging to 11 taxonomic orders, and categorized as per intensity of resilience using selected criteria. Perception-based climate-resilient adaptation strategies have also been discussed. Developing appropriate adaptation policies and implementing climate-resilient practices and management can minimize vulnerability and increase the adaptive capacity of fishers ensuring sustainable livelihood options.


Assuntos
Ecossistema , Áreas Alagadas , Animais , Ecologia , Mudança Climática , Índia
2.
Chem Biodivers ; : e202401899, 2024 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-39462980

RESUMO

The toxicity associated with synthetic drugs used for treating various diseases is common. This led to a growing interest in searching and incorporating natural functional core structures such as flavonoid and their derivatives via chemical modifications to overcome the toxicity problems and enhance their biological spectrum. Natural core structures such as flavonoids are accepted due to their safety to the environment and owing to their varieties of biological activities such as anti-Alzheimer, antimicrobial, anticancer, anti-inflammatory, antidiabetics, and antiviral properties. Based on their chemical structure, flavonoids are classified into various classes such as flavone, flavanol, flavanone, isoflavone, and Anthocyanin, etc. The present review focuses on the potential role of the flavonoid ring-containing derivatives, highlighting their ability to prevent and treat non-communicable diseases such as diabetes, Alzheimer's, and cancer. The pharmacological activities of the flavonoid's derivatives are mainly attributed to their antioxidant effects against free radicals, and reactive oxygen species as well as their ability to act as enzymes inhibitors. The review covers the synthetic strategies of flavonoid derivatives, structure activity relationship (SAR), and in silico studies to improve the efficacy of these compounds. The SAR, molecular docking analysis will enable medicinal chemists to search further, develop potent and newer therapeutic agents.

3.
Phys Chem Chem Phys ; 25(34): 22583-22594, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-37435670

RESUMO

Using correlation plots of binding energy and electron density at the bond critical point, we investigated the nature of intermolecular non-covalent bonds (D-X⋯A, where D = O/S/F/Cl/Br/H, mostly, X = main group elements (except noble gases), A = H2O, NH3, H2S, PH3, HCHO, C2H4, HCN, CO, CH3OH, and CH3OCH3). The binding energies were calculated at the MP2 level of theory, followed by Atoms in Molecules (AIM) analysis of the ab initio wave functions to obtain the electron density at the bond critical point (BCP). For each non-covalent bond, the slopes of the binding energy versus electron density plot have been determined. Based on their slopes, non-covalent bonds are classified as non-covalent bond closed-shell (NCB-C) or non-covalent bond shared-shell (NCB-S). Intriguingly, extrapolating the slopes of the NCB-C and NCB-S cases leads to intramolecular "ionic" and "covalent" bonding regimes, establishing a link between such intermolecular non-covalent and intramolecular chemical bonds. With this new classification, hydrogen bonds and other non-covalent bonds formed by a main-group atom in a covalent molecule are classified as NCB-S. Atoms found in ionic molecules generally form NCB-C type bonds, with the exception of carbon which also forms NCB-C type bonds. Molecules with a tetravalent carbon do behave like ions in ionic molecules such as NaCl and interact with other molecules through NCB-C type bonds. As with the chemical bonds, there are some non-covalent bonds that are intermediate cases.

4.
J Phys Chem A ; 127(40): 8415-8426, 2023 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-37782474

RESUMO

The oxidation-reduction reactions of disulfides are important in both chemistry and biology. Dimethyl disulfide (DMDS), the smallest reduced sulfur species with a disulfide bond, is emitted in significant quantities from natural sources and contributes to the formation of aerosols and hazardous haze. Although atmospheric removal of DMDS via the reactions with OH or NO3 radicals and photolysis is known, the reactions of DMDS with other atmospheric oxidants are yet to be explored. Herein, using quantum chemical calculations, we explored the reactions of DMDS with CH2OO (formaldehyde oxide) and other methyl-substituted Criegee intermediates. The various reaction pathways evaluated were found to have positive energy barriers. However, in the presence of formic acid, a direct oxygen-transfer pathway leading to the corresponding sulfoxide (CH3SS(O)CH3) was found to proceed through a submerged transition state below the separated reactants. Calculations for the methyl-substituted Criegee intermediates, particularly for anti-CH3CHOO, show a significant increase in the rate of the direct oxygen-transfer reaction when catalyzed by formic acid. The presence of formic acid also alters the mechanism and reduces the enthalpic barrier of a second pathway, forming thioformaldehyde and hydroperoxide without any rate enhancement. Our data indicated that, although Criegee intermediates are unlikely to be an important atmospheric sink of DMDS under normal conditions, in regions rich in DMDS and formic acid, the formic acid-catalyzed Criegee intermediate-mediated oxidation of DMDS via the direct oxygen-transfer pathway could lead to organic sulfur compounds contributing to atmospheric aerosol.

5.
Phys Chem Chem Phys ; 24(47): 28913-28922, 2022 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-36416102

RESUMO

The non-covalent bonds formed by group 1 and group 2 elements were systematically analysed by ab initio calculations at the MP2/aug-cc-pVDZ (for Ca, 6-311++G(2df,p) basis sets were used) level of theory to classify the weak bonds, followed by Atoms in Molecules (AIM) analysis of the ab initio wave functions. It has been established that there is a strong correlation between the electron density at the non-covalent bond critical point (BCP) and the binding energy for each homogeneous sample of complexes. The slopes of the electron density versus binding energy plot have been obtained for group 1 and group 2 donor molecules (Dn-X⋯A, for X = H, D = F/-OH/-SH, for X = Li, Na, D = F/Cl/Br and for X = Be, Mg, and Ca, D = F/Cl/H) with a set of acceptor molecules (A), which includes H2O, NH3, H2S, PH3, HCHO, C2H4, HCN, CO, CH3OH and CH3OCH3. The bonds formed by group 1 (except H-bonds) and group 2 belong to a high slope dominated by electrostatics, with several similarities, leading us to propose a common name, 'alkalene bond', for non-covalent bonding in alkali and alkaline earth metals.

6.
J Environ Manage ; 302(Pt A): 113948, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34678541

RESUMO

Biological pre-treatment is the removal of recalcitrant lignin from lignocellulose through the action of lignin degrading organisms and/or their ligninolytic enzymes system. Despite numerous environmental benefits, biological pre-treatment has been side-lined due to its prolonged periods of fermentation, ascribed to the slow growth rate of lignin degrading organisms. Thus, the present work adopted a dual phase statistical optimization approach for the biological pre-treatment of sugarcane bagasse, with Pycnoporus coccineus MScMS1, using Taguchi Orthogonal Array, in conjunction with Response Surface Methodology, to address this issue. Amplification of the organism's functioning resulted in an enhancement of sugar productivity and yield accompanied by a significant reduction in fermentation time. Optimized sugar concentration was approx. 18 g/L within 4 days of pre-treatment, with productivity of 4.5 g/(L.day). Substrate compositional analysis revealed significant (p < 0.05) reduction of lignin by 70% in the biologically pre-treated substrate, along with significantly (p < 0.05) higher quantities of water soluble components (35 ± 0.95 g) and cellulose content (33 ± 0.18 g), as compared to the untreated substrate. Appreciable levels of xylose, arabinose, glucose and galactose were detected in hydrolysates from biologically pre-treated bagasse. Furthermore, Bacillus megaterium Ti3, a potent polyhydroxyalkanoates (PHA) producer, was grown on these sugar-rich hydrolysates and generated 0.58 g/L PHA in 24 h of fermentation accompanied by 0.88 g/L dry cell weight and 65% PHA accumulation. These results were comparable with those from a glucose medium. Thus, the present study was successful in optimizing the biological pre-treatment of sugarcane bagasse and utilizing the resultant sugar-rich hydrolysates, as inexpensive and renewable raw materials, for PHA production.


Assuntos
Poli-Hidroxialcanoatos , Saccharum , Celulose , Polyporaceae
7.
Genomics ; 112(6): 4701-4714, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32827671

RESUMO

Methods of finding sequence similarity play a significant role in computational biology. Owing to the rapid increase of genome sequences in public databases, the evolutionary relationship of species becomes more challenging. But traditional alignment-based methods are found inappropriate due to their time-consuming nature. Therefore, it is necessary to find a faster method, which applies to species phylogeny. In this paper, a new graph-theory based alignment-free sequence comparison method is proposed. A complete-bipartite graph is used to represent each genome sequence based on its nucleotide triplets. Subsequently, with the help of the weights of edges of the graph, a vector descriptor is formed. Finally, the phylogenetic tree is drawn using the UPGMA algorithm. In the present case, the datasets for comparison are related to mammals, viruses, and bacteria. In most of the cases, the phylogeny in the present case is found to be more satisfactory as compared to earlier methods.


Assuntos
Biologia Computacional , Análise de Sequência de DNA/métodos , Algoritmos , Animais , Bactérias/genética , Mamíferos/genética , Nucleotídeos/genética , Filogenia , Vírus/genética
8.
Prep Biochem Biotechnol ; 51(10): 1046-1055, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33719922

RESUMO

2,3-Butanediol (2,3-BDO) has varied applications in chemical, pharmaceutical, & food industry. Microorganisms belonging to Klebsiella, Enterobacter & Serratia genera are well-known producers of 2,3-BDO. However, they have limited usage in industrial-scale owing to their pathogenic nature. A nonpathogenic soil isolate identified as Bacillus licheniformis (BL1) was thus investigated for 2,3-BDO production. Soy flakes, soy flour, defatted soy, and soybean meal-based hydrolysates replaced yeast extract and peptone as nitrogen sources. Defatted soy flakes and soybean meal hydrolysate led to an equivalent 2,3-BDO yield and productivity as compared to that of Yeast Extract and peptone. The pH and oxygen variation influenced the proportion of various products of the mixed acid-butanediol pathway. Further, the batch mode fermentation with soy hydrolysate and optimized process parameter resulted in 2,3-BDO titer, yield and productivity of 11.06 g/L, 0.43 g/g and 0.48 g/L h respectively. Glucose concentration above 5% was inhibitory and led to reduction in the specific growth rate of BL1 in batch cultivation. Intermittent glucose feeding in fed-batch mode overcame this substrate limitation resulting in increased titers (49.8 g/L) and productivity (0.62 g/L h). Modified medium containing soy hydrolysate as nitrogen source with fermentation process optimization resulted in 67% decrease in medium cost for 2,3-BDO production.


Assuntos
Bacillus licheniformis/metabolismo , Butileno Glicóis/metabolismo , Meios de Cultura/metabolismo , Fermentação , Glucose/metabolismo , Microbiologia Industrial/métodos , Nitrogênio/metabolismo , Glycine max/metabolismo
9.
Sensors (Basel) ; 20(23)2020 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-33260347

RESUMO

In recent years, hyperspectral images (HSIs) have attained considerable attention in computer vision (CV) due to their wide utility in remote sensing. Unlike images with three or lesser channels, HSIs have a large number of spectral bands. Recent works demonstrate the use of modern deep learning based CV techniques like convolutional neural networks (CNNs) for analyzing HSI. CNNs have receptive fields (RFs) fueled by learnable weights, which are trained to extract useful features from images. In this work, a novel multi-receptive CNN module called GhoMR is proposed for HSI classification. GhoMR utilizes blocks containing several RFs, extracting features in a residual fashion. Each RF extracts features which are used by other RFs to extract more complex features in a hierarchical manner. However, the higher the number of RFs, the greater the associated weights, thus heavier is the network. Most complex architectures suffer from this shortcoming. To tackle this, the recently found Ghost module is used as the basic building unit. Ghost modules address the feature redundancy in CNNs by extracting only limited features and performing cheap transformations on them, thus reducing the overall parameters in the network. To test the discriminative potential of GhoMR, a simple network called GhoMR-Net is constructed using GhoMR modules, and experiments are performed on three public HSI data sets-Indian Pines, University of Pavia, and Salinas Scene. The classification performance is measured using three metrics-overall accuracy (OA), Kappa coefficient (Kappa), and average accuracy (AA). Comparisons with ten state-of-the-art architectures are shown to demonstrate the effectiveness of the method further. Although lightweight, the proposed GhoMR-Net provides comparable or better performance than other networks. The PyTorch code for this study is made available at the iamarijit/GhoMR GitHub repository.

10.
J Basic Microbiol ; 60(8): 661-668, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32515847

RESUMO

Intravascular thrombosis is a prime cause of cardiac complications worldwide. Microbial fibrinolytic proteases are of clinical significance in thrombosis treatment. The present study discusses the purification and characterization of a protease from Bacillus cereus S46, ascertaining its in vitro thrombolytic activity against a blood clot. By the three-step purification involving precipitation, dialysis, and diethylaminoethyl-cellulose ion-exchange chromatography, a 12.37-fold purification of the enzyme to homogeneity was achieved. The apparent molecular mass of the protease was 30 kDa, as found by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimum activity of the enzyme was observed at pH 8.0 and 40°C. The enzyme retained an 82.19% residual activity at pH 8.0 and 40°C for 1 h. The Km and Vmax values of the protease with casein were 0.0027 mM and 9.712 µmol/min, respectively. In an in vitro assay, the purified protease resulted in 97.02% lysis of the blood clot. The fibrinolytic potential of the enzyme, together with its characteristics of being active and stable under near-physiological conditions, may suggest its application as a therapeutic agent.


Assuntos
Bacillus cereus/enzimologia , Proteínas de Bactérias/farmacologia , Fibrinolíticos/farmacologia , Peptídeo Hidrolases/farmacologia , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/metabolismo , Caseínas/metabolismo , Estabilidade Enzimática , Fibrinolíticos/química , Fibrinolíticos/isolamento & purificação , Fibrinolíticos/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Peso Molecular , Peptídeo Hidrolases/química , Peptídeo Hidrolases/isolamento & purificação , Peptídeo Hidrolases/metabolismo , Temperatura
11.
Radiology ; 292(3): 608-617, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31361205

RESUMO

BackgroundThe establishment of a timely and correct diagnosis in heart failure-like myocarditis remains one of the most challenging in clinical cardiology.PurposeTo assess the diagnostic potential of texture analysis in heart failure-like myocarditis with comparison to endomyocardial biopsy (EMB) as the reference standard.Materials and MethodsSeventy-one study participants from the Magnetic Resonance Imaging in Myocarditis (MyoRacer) trial (ClinicalTrials.gov registration no. NCT02177630) with clinical suspicion for myocarditis and symptoms of heart failure were prospectively included (from August 2012 to May 2015) in the study. Participants underwent biventricular EMB and cardiac MRI at 1.5 T, including native T1 and T2 mapping and standard Lake Louise criteria. Texture analysis was applied on T1 and T2 maps by using an open-source software. Stepwise dimension reduction was performed for selecting features enabling the diagnosis of myocarditis. Diagnostic performance was assessed from the area under the curve (AUC) from receiver operating characteristic analyses with 10-fold cross validation.ResultsIn participants with acute heart failure-like myocarditis (n = 31; mean age, 47 years ± 17; 10 women), the texture feature GrayLevelNonUniformity from T2 maps (T2_GLNU) showed diagnostic performance similar to that of mean myocardial T2 time (AUC, 0.69 for both). The combination of mean T2 time and T2_GLNU had the highest AUC (0.76; 95% confidence interval [CI]: 0.43, 0.95), with sensitivity of 81% (25 of 31) and specificity of 71% (22 of 31). In patients with chronic heart failure-like myocarditis (n = 40; mean age, 48 years ± 13; 12 women), the histogram feature T2_kurtosis demonstrated superior diagnostic performance compared to that of all other single parameters (AUC, 0.81; 95% CI: 0.66, 0.96). The combination of the two texture features, T2_kurtosis and the GrayLevelNonUniformity from T1, had the highest diagnostic performance (AUC, 0.85; 95% CI: 0.57, 0.90; sensitivity, 90% [36 of 40]; and specificity, 72% [29 of 40]).ConclusionIn this proof-of-concept study, texture analysis applied on cardiac MRI T1 and T2 mapping delivers quantitative imaging parameters for the diagnosis of acute or chronic heart failure-like myocarditis and might be superior to Lake Louise criteria or averaged myocardial T1 or T2 values.© RSNA, 2019Online supplemental material is available for this article.See also the editorial by de Roos in this issue.


Assuntos
Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Miocardite/complicações , Miocardite/diagnóstico por imagem , Doença Aguda , Adulto , Doença Crônica , Diagnóstico Diferencial , Feminino , Coração/diagnóstico por imagem , Insuficiência Cardíaca/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Miocardite/patologia , Miocárdio/patologia , Estudos Prospectivos , Sensibilidade e Especificidade
12.
Angew Chem Int Ed Engl ; 57(46): 15199-15203, 2018 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-30265433

RESUMO

Ice and solid H2 S look as different as pears and oranges, leading Pauling to conclude that H2 O has hydrogen bonds and H2 S has van der Waals interactions. Now it is shown that the H2 S dimer, like the H2 O dimer, is indeed hydrogen-bonded.

13.
Mol Syst Biol ; 12(12): 896, 2016 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-28007935

RESUMO

Organisms use circadian clocks to generate 24-h rhythms in gene expression. However, the clock can interact with other pathways to generate shorter period oscillations. It remains unclear how these different frequencies are generated. Here, we examine this problem by studying the coupling of the clock to the alternative sigma factor sigC in the cyanobacterium Synechococcus elongatus Using single-cell microscopy, we find that psbAI, a key photosynthesis gene regulated by both sigC and the clock, is activated with two peaks of gene expression every circadian cycle under constant low light. This two-peak oscillation is dependent on sigC, without which psbAI rhythms revert to one oscillatory peak per day. We also observe two circadian peaks of elongation rate, which are dependent on sigC, suggesting a role for the frequency doubling in modulating growth. We propose that the two-peak rhythm in psbAI expression is generated by an incoherent feedforward loop between the clock, sigC and psbAI Modelling and experiments suggest that this could be a general network motif to allow frequency doubling of outputs.


Assuntos
Relógios Circadianos , Complexo de Proteína do Fotossistema II/metabolismo , Fator sigma/metabolismo , Synechococcus/fisiologia , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Modelos Biológicos , Imagem Molecular , Fotossíntese , Análise de Célula Única , Imagem com Lapso de Tempo
14.
J Basic Microbiol ; 57(2): 95-103, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27874973

RESUMO

Benzo[a]pyrene, a high molecular weight polycyclic aromatic hydrocarbon possesses carcinogenic, teratogenic, and mutagenic properties. The present study focuses on benzo[a]pyrene degradation by Pleurotus ostreatus PO-3, characterization and identification of metabolites produced and the extent of degradation in the presence of axenic culture of P. ostreatus PO-3 and defined co-cultures of the basidiomycete with bacteria and non-basidiomycete fungi. Thin-layer chromatography revealed that P. ostreatus PO-3 transformed benzo[a]pyrene to polar metabolites. Following degradation, appearance of numerous peaks in the mass spectrum indicated that benzo[a]pyrene degradation was a result of the metabolic activity of P. ostreatus PO-3. A degradation product corresponding to the m/z 284.2 was detected which could possibly be BaP-quinone, resulting from the oxidation of benzo[a]pyrene. Compared to the axenic culture of P. ostreatus PO-3 (64.3%), co-cultures of P. ostreatus PO-3 and Penicillium chrysogenum MTCC 787 and P. ostreatus PO-3 and Pseudomonas aeruginosa MTCC 1688 could degrade 86.1 and 75.1% of benzo[a]pyrene, respectively. Thus it could be inferred from the present investigation that the combined catabolic activities of P. ostreatus PO-3 with bacteria and non-basidiomycete fungi can produce synergistic effects to enhance BaP degradation. The increase in the generation of polar metabolites as degradation products from the recalcitrant parent compound advocates the potential application of P. ostreatus PO-3 in benzo[a]pyrene bioremediation.


Assuntos
Benzo(a)pireno/metabolismo , Penicillium chrysogenum/metabolismo , Pleurotus/metabolismo , Pseudomonas aeruginosa/metabolismo , Biotransformação , Cromatografia em Camada Fina , Técnicas de Cocultura , Espectrometria de Massas
15.
J Basic Microbiol ; 57(2): 114-120, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27709654

RESUMO

Filamentous fungi are efficient producers of lipases. The present study focuses on identification of a potent lipolytic fungus and enhancement of lipase production through optimization of nutritional and cultural conditions under submerged fermentation. Molecular characterization of the fungus by 18S rDNA sequencing revealed its identity as Aspergillus tamarii with 98% homology. Maximum lipase production was noted in mineral salts medium supplemented with coconut oil (2.5%, v/v). A combination of ammonium chloride (2%, w/v) and tryptone (2%, w/v) facilitated maximum lipase production at pH 5 of the production medium. A carbon: nitrogen ratio of 1:4 led to significant (p < 0.00008) increase in the enzyme production in the presence of surfactant cetyltrimethylammonium bromide (0.5%, w/v). Maximum lipase activity (2,32,500 ± 192 U/ml/min) was recorded after 7 days of incubation at 25 °C on a rotary shaker at 120 rpm. A 9.8-fold increase in lipase activity was recorded after optimization of the process parameters. Addition of crude lipase enhanced the oil stain removal activity of a commercially available detergent by 2.2-fold. The current findings suggest the potentiality of this fungal lipase to be used in detergent formulation.


Assuntos
Aspergillus/enzimologia , Aspergillus/metabolismo , Lipase/biossíntese , Óleos de Plantas/metabolismo , Aspergillus/crescimento & desenvolvimento , Óleo de Coco , Meios de Cultura/química , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Inibidores Enzimáticos/metabolismo , Fermentação , RNA Ribossômico 18S/genética , Análise de Sequência de DNA , Tensoativos/metabolismo , Temperatura
16.
Mol Microbiol ; 94(2): 450-65, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25171378

RESUMO

The co-ordinated regulation of heat shock proteins is critically important for the stress response of M. tuberculosis, failure of which results in enhanced immune recognition of the tubercle bacilli with reduced survival during chronic infections. In this study, we show that PhoP regulates the transcription of α-crystallin 2 (acr2), expression of which increases more than any other gene of M. tuberculosis during heat-shock or following macrophage infection. We also show that regulation of acr2 by PhoP is attributable to direct regulator-promoter interactions at specific sites proximal to a sequence motif comprising the target site of another virulence factor, HspR. While both these regulators, on their own, are capable of influencing acr2 expression, remarkably our results show that the two virulence regulators PhoP and HspR interact with each other to influence their in vivo recruitment at the acr2 regulatory region, and in turn, contribute to stress-specific regulation of acr2 expression. We propose a model to suggest how protein-protein interactions between PhoP and HspR influence the regulation of α-crystallin 2, an essential pathogenic determinant of M. tuberculosis.


Assuntos
Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Redes Reguladoras de Genes , Proteínas de Choque Térmico/metabolismo , Resposta ao Choque Térmico , Mycobacterium tuberculosis/efeitos da radiação , Proteínas Repressoras/metabolismo , alfa-Cristalinas/metabolismo , Sítios de Ligação , Proteínas Correpressoras/metabolismo , Macrófagos/imunologia , Macrófagos/microbiologia , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/fisiologia , Regiões Promotoras Genéticas , Mapeamento de Interação de Proteínas
17.
J Biol Chem ; 288(40): 29182-92, 2013 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-23963455

RESUMO

Mycobacterium tuberculosis PhoP, a master regulator involved in complex lipid biosynthesis and expression of unknown virulence determinants, is composed of an N-terminal receiver domain and a C-terminal effector domain. The two experimentally characterized PhoP orthologs, from Escherichia coli and Salmonella enterica, display vastly different regulatory capabilities. Here, we demonstrate that the 20-residue-long N-terminal arm unique to M. tuberculosis PhoP plays an essential role in the expanded regulatory capabilities of this important regulator. Although the arm is not required for overall structural stability and/or phosphorylation of the PhoP N-domain, strikingly it is essential for phosphorylation-coupled transcription regulation of target genes. Consistent with this view, arm truncation of PhoP is accompanied by a conformational change of the effector domain, presenting a block in activation subsequent to phosphorylation. These results suggest that presence of the arm, unique to this regulator that shares an otherwise highly conserved domain structure with members of the protein family, contributes to the mechanism of inter-domain interactions. Thus, we propose that the N-terminal arm is an adaptable structural feature of M. tuberculosis PhoP, which evolved to fine-tune regulatory capabilities of the transcription factor in response to the changing physiology of the bacilli within its host.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Mycobacterium tuberculosis/metabolismo , Sequência de Aminoácidos , Aminoácidos/metabolismo , DNA Bacteriano/metabolismo , Eletroforese em Gel Bidimensional , Dados de Sequência Molecular , Proteínas Mutantes/metabolismo , Organofosfatos/metabolismo , Fosforilação , Regiões Promotoras Genéticas/genética , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Relação Estrutura-Atividade , Tripsina/metabolismo
18.
Indian J Med Res ; 139(6): 921-6, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25109727

RESUMO

BACKGROUND & OBJECTIVES: Arthropods of different taxonomic identity including chironomid midges are known to induce allergic response in humans. The present study was done to access two common chironomid species Chironomus circumdatus and Polypedilum nubifer for their sensitizing potential as an allergen in atopic patients and controls. METHODS: Following preparation of allergenic extracts of the two chironomid species separately, 198 atopic patients attending an allergy clinic and 50 age matched controls were tested along with a routine panel of allergens to assess sensitization. RESULTS: The skin prick test (SPT) results revealed that 189 of the 198 patients (95.4%) demonstrated sensitization to both the chironomid species. Higher levels of total IgE was observed in atopic subjects than in the control group. INTERPRETATION & CONCLUSIONS: The results suggest that the chironomid midges Chironomus circumdatus and Polypedilum nubifer can elicit sensitization in humans. A potential risk for allergic reactions by susceptible individuals exists due to these chironomid species, owing to their abundance and chances of contact with human beings. Further studies may be initiated to characterize the nature of the allergens and to assess their clinical relevance.


Assuntos
Alérgenos/imunologia , Chironomidae/imunologia , Hipersensibilidade/imunologia , Análise de Variância , Animais , Humanos , Imunoglobulina E/imunologia , Índia , Pele/imunologia , Especificidade da Espécie , Estatísticas não Paramétricas
19.
World J Microbiol Biotechnol ; 30(8): 2315-24, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24770873

RESUMO

Aflatoxin B1 (AFB1) is a highly toxic fungal metabolite having carcinogenic, mutagenic and teratogenic effects on human and animal health. Accidental feeding of aflatoxin-contaminated rice straw may be detrimental for ruminant livestock and can lead to transmission of this toxin or its metabolites into the milk of dairy cattle. White-rot basidiomycetous fungus Pleurotus ostreatus produces ligninolytic enzymes like laccase and manganese peroxidase (MnP). These extracellular enzymes have been reported to degrade many environmentally hazardous compounds. The present study examines the ability of P. ostreatus strains to degrade AFB1 in rice straw in the presence of metal salts and surfactants. Laccase and MnP activities were determined spectrophotometrically. The efficiency of AFB1 degradation was evaluated by high performance liquid chromatography. Highest degradation was recorded for both P. ostreatus MTCC 142 (89.14 %) and P. ostreatus GHBBF10 (91.76 %) at 0.5 µg mL(-1) initial concentration of AFB1. Enhanced degradation was noted for P. ostreatus MTCC 142 in the presence of Cu(2+) and Triton X-100, at toxin concentration of 5 µg mL(-1). P. ostreatus GHBBF10 showed highest degradation in the presence of Zn(2+) and Tween 80. Liquid chromatography-mass spectrometric analysis revealed the formation of hydrated, decarbonylated and O-dealkylated products. The present findings suggested that supplementation of AFB1-contaminated rice straw by certain metal salts and surfactants can improve the enzymatic degradation of this mycotoxin by P. ostreatus strains.


Assuntos
Aflatoxina B1/metabolismo , Oryza/química , Oryza/microbiologia , Pleurotus/enzimologia , Pleurotus/isolamento & purificação , Tensoativos/farmacologia , Biodegradação Ambiental , Cloretos/farmacologia , Proteínas Fúngicas/metabolismo , Lacase/metabolismo , Metais Pesados/farmacologia , Octoxinol/metabolismo , Peroxidases/metabolismo , Pleurotus/classificação , Polissorbatos/metabolismo , Espectrofotometria , Sulfatos/farmacologia , Oligoelementos/farmacologia
20.
Environ Sci Pollut Res Int ; 31(22): 32350-32370, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38649612

RESUMO

In evaluating the integrated remote sensing-based ecological index (RSEIPCA), principal component analysis (PCA) has been extensively utilized. However, the conventional PCA-based RSEI (RSEIPCA) cannot accurately evaluate component indicators' spatially shifting relative significance. This study presented a novel RSEI evaluation strategy based on geographically weighted principal component analysis (RSEIGWPCA) to address this deficiency. Second, compared to the classic RSEIPCA, RSEIGWPCA was tested at English Bazar and surrounding areas using two-fold validation. In this regard, the Jaccard test from a different setting and correlation analysis were utilized to examine the geographical distribution of RSEI derived by PCA and GWPCA. The validation output revealed better effectiveness of GWPCA over PCA in assessing the RSEI. The findings revealed that (i) in RSEI assessment, the spatial heterogeneity of the dataset helped to formulate individual weights by GWPCA that was not performed by PCA; and (ii) the areas having higher RSEI were primarily located around the Chatra wetland of this study area, and the areas with lower RSEI were located mainly in the industrial part. It has been concluded that RSEIGWPCA is a helpful approach in the RSEI evaluating for the regional and local scale like English bazaar city and its neighbourhood.


Assuntos
Monitoramento Ambiental , Análise de Componente Principal , Tecnologia de Sensoriamento Remoto , Monitoramento Ambiental/métodos , Ecologia
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