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1.
Am J Physiol Lung Cell Mol Physiol ; 327(3): L395-L405, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39076085

RESUMO

Pseudomonas aeruginosa utilizes a type 3 secretion system to intoxicate host cells with the nucleotidyl cyclase ExoY. After activation by its host cell cofactor, filamentous actin, ExoY produces purine and pyrimidine cyclic nucleotides, including cAMP, cGMP, and cUMP. ExoY-generated cyclic nucleotides promote interendothelial gap formation, impair motility, and arrest cell growth. The disruptive activities of cAMP and cGMP during the P. aeruginosa infection are established; however, little is known about the function of cUMP. Here, we tested the hypothesis that cUMP contributes to endothelial cell barrier disruption during P. aeruginosa infection. Using a membrane permeable cUMP analog, cUMP-AM, we revealed that during infection with catalytically inactive ExoY, cUMP promotes interendothelial gap formation in cultured pulmonary microvascular endothelial cells (PMVECs) and contributes to increased filtration coefficient in the isolated perfused lung. These findings indicate that cUMP contributes to endothelial permeability during P. aeruginosa lung infection.NEW & NOTEWORTHY During pneumonia, bacteria utilize a virulence arsenal to communicate with host cells. The Pseudomonas aeruginosa T3SS directly introduces virulence molecules into the host cell cytoplasm. These molecules are enzymes that trigger interkingdom communication. One of the exoenzymes is a nucleotidyl cyclase that produces noncanonical cyclic nucleotides like cUMP. Little is known about how cUMP acts in the cell. Here we found that cUMP instigates pulmonary edema during Pseudomonas aeruginosa infection of the lung.


Assuntos
Células Endoteliais , Nucleotídeos Cíclicos , Infecções por Pseudomonas , Pseudomonas aeruginosa , Animais , Humanos , Camundongos , Proteínas de Bactérias/metabolismo , Células Cultivadas , Células Endoteliais/metabolismo , Células Endoteliais/microbiologia , Junções Comunicantes/metabolismo , Glucosiltransferases , Pulmão/microbiologia , Pulmão/metabolismo , Pulmão/patologia , Nucleotídeos Cíclicos/metabolismo , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidade , Infecções por Pseudomonas/microbiologia , Infecções por Pseudomonas/metabolismo , Infecções por Pseudomonas/patologia , Sistemas de Secreção Tipo III/metabolismo
2.
Proc Natl Acad Sci U S A ; 117(28): 16333-16338, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32601241

RESUMO

Bacterial transfer RNAs (tRNAs) contain evolutionarily conserved sequences and modifications that ensure uniform binding to the ribosome and optimal translational accuracy despite differences in their aminoacyl attachments and anticodon nucleotide sequences. In the tRNA anticodon stem-loop, the anticodon sequence is correlated with a base pair in the anticodon loop (nucleotides 32 and 38) to tune the binding of each tRNA to the decoding center in the ribosome. Disruption of this correlation renders the ribosome unable to distinguish correct from incorrect tRNAs. The molecular basis for how these two tRNA features combine to ensure accurate decoding is unclear. Here, we solved structures of the bacterial ribosome containing either wild-type [Formula: see text] or [Formula: see text] containing a reversed 32-38 pair on cognate and near-cognate codons. Structures of wild-type [Formula: see text] bound to the ribosome reveal 23S ribosomal RNA (rRNA) nucleotide A1913 positional changes that are dependent on whether the codon-anticodon interaction is cognate or near cognate. Further, the 32-38 pair is destabilized in the context of a near-cognate codon-anticodon pair. Reversal of the pairing in [Formula: see text] ablates A1913 movement regardless of whether the interaction is cognate or near cognate. These results demonstrate that disrupting 32-38 and anticodon sequences alters interactions with the ribosome that directly contribute to misreading.


Assuntos
Biossíntese de Proteínas/genética , RNA de Transferência/química , RNA de Transferência/genética , Anticódon/química , Anticódon/genética , Anticódon/metabolismo , Pareamento de Bases , Códon/genética , Códon/metabolismo , Cristalografia por Raios X , Modelos Moleculares , Mutação , Conformação de Ácido Nucleico , RNA Bacteriano/química , RNA Bacteriano/genética , RNA Bacteriano/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Ribossômico 23S/química , RNA Ribossômico 23S/genética , RNA Ribossômico 23S/metabolismo , RNA de Transferência/metabolismo , Ribossomos/química , Ribossomos/metabolismo , Thermus thermophilus/genética , Thermus thermophilus/metabolismo
3.
Am J Physiol Lung Cell Mol Physiol ; 323(1): L48-L57, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35672011

RESUMO

The lungs of patients with acute respiratory distress syndrome (ARDS) have hyperpermeable capillaries that must undergo repair in an acidic microenvironment. Pulmonary microvascular endothelial cells (PMVECs) have an acid-resistant phenotype, in part due to carbonic anhydrase IX (CA IX). CA IX also facilitates PMVEC repair by promoting aerobic glycolysis, migration, and network formation. Molecular mechanisms of how CA IX performs such a wide range of functions are unknown. CA IX is composed of four domains known as the proteoglycan-like (PG), catalytic (CA), transmembrane (TM), and intracellular (IC) domains. We hypothesized that the PG and CA domains mediate PMVEC pH homeostasis and repair, and the IC domain regulates aerobic glycolysis and PI3k/Akt signaling. The functions of each CA IX domain were investigated using PMVEC cell lines that express either a full-length CA IX protein or a CA IX protein harboring a domain deletion. We found that the PG domain promotes intracellular pH homeostasis, migration, and network formation. The CA and IC domains mediate Akt activation but negatively regulate aerobic glycolysis. The IC domain also supports migration while inhibiting network formation. Finally, we show that exposure to acidosis suppresses aerobic glycolysis and migration, even though intracellular pH is maintained in PMVECs. Thus, we report that 1) the PG and IC domains mediate PMVEC migration and network formation, 2) the CA and IC domains support PI3K/Akt signaling, and 3) acidosis impairs PMVEC metabolism and migration independent of intracellular pH homeostasis.


Assuntos
Antígenos de Neoplasias , Anidrase Carbônica IX , Células Endoteliais , Pulmão , Acidose/metabolismo , Antígenos de Neoplasias/química , Antígenos de Neoplasias/metabolismo , Anidrase Carbônica IX/metabolismo , Células Endoteliais/citologia , Células Endoteliais/enzimologia , Humanos , Concentração de Íons de Hidrogênio , Pulmão/irrigação sanguínea , Pulmão/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteoglicanas/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Microambiente Tumoral
4.
Am J Physiol Lung Cell Mol Physiol ; 321(2): L358-L376, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34159794

RESUMO

Capillary endothelial cells possess a specialized metabolism necessary to adapt to the unique alveolar-capillary environment. Here, we highlight how endothelial metabolism preserves the integrity of the pulmonary circulation by controlling vascular permeability, defending against oxidative stress, facilitating rapid migration and angiogenesis in response to injury, and regulating the epigenetic landscape of endothelial cells. Recent reports on single-cell RNA-sequencing reveal subpopulations of pulmonary capillary endothelial cells with distinctive reparative capacities, which potentially offer new insight into their metabolic signature. Lastly, we discuss broad implications of pulmonary vascular metabolism on acute respiratory distress syndrome, touching on emerging findings of endotheliitis in coronavirus disease 2019 (COVID-19) lungs.


Assuntos
COVID-19/complicações , Endotélio Vascular/metabolismo , Neovascularização Patológica/patologia , Circulação Pulmonar , Síndrome do Desconforto Respiratório/epidemiologia , SARS-CoV-2/isolamento & purificação , COVID-19/transmissão , COVID-19/virologia , Endotélio Vascular/patologia , Endotélio Vascular/virologia , Humanos , Neovascularização Patológica/metabolismo , Neovascularização Patológica/virologia , Síndrome do Desconforto Respiratório/metabolismo , Síndrome do Desconforto Respiratório/patologia , Síndrome do Desconforto Respiratório/virologia
5.
Microb Pathog ; 158: 105104, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34298126

RESUMO

Anthrax, by Bacillus anthracis, remains a dreadful fatal hazard worldwide. The currently used anthrax vaccines are plagued by numerous issues that limit their widespread use. As an immunization approach targeting both extracellular antigens and toxins of B. anthracis may achieve better sterile immunity, the present investigation designed a bicistronic secretory anti-anthrax DNA vaccine targeting immune response against toxin and cells. The efficacy of the vaccine was compared with monocistronic DNA vaccines and the currently used anthrax vaccine. For this, mice were immunized with the developed vaccine containing pag (encoding protective antigen to block toxin) and eag genes (encoding EA1 to target cells) of B. anthracis through DNA-prime/Protein-boost (D/P) and DNA prime/DNA-boost (D/D) approaches. There was a >2 and > 5 fold increase in specific antibody level by D/D and D/P approaches respectively, on 42nd days post-immunization (dpi). Serum cytokine profiling showed that both Th1 and Th2 immune responses were elicited, with more Th2 responses in D/P strategy. More importantly, challenge with 100 times LD50 of B. anthracis at 42nd dpi exhibited maximum cumulative survival (83.33 %) by bicistronic D/P approach. Remarkably, immunization with EA1 delayed mortality onset in infection. The study forms the first report on complement-dependent bactericidal activity of antiEA1 antibodies. In short, co-immunization of PA and EA1 through the developed bicistronic DNA vaccine would be an effective immunization approach in anthrax vaccination. Further, D/P strategy could enhance vaccine-induced immunity against B. anthracis. Altogether, the study generates certain critical insights having direct applications in next-generation vaccine development against anthrax.


Assuntos
Vacinas contra Antraz , Bacillus anthracis , Vacinas de DNA , Animais , Vacinas contra Antraz/genética , Anticorpos Antibacterianos , Antígenos de Bactérias/genética , Bacillus anthracis/genética , DNA , Imunidade , Camundongos , Camundongos Endogâmicos BALB C , Vacinação , Vacinas de DNA/genética
6.
Biologicals ; 69: 59-65, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33309531

RESUMO

Distressing effects on animal and human health with lethal progression, being used as bioweapon and shared features with non-pathogenic bacteria demands sensitive, specific, safe, cost effective and rapid detection methods for anthrax causing organisms. Conventional microbiology based diagnostics for anthrax are time consuming and need sophisticated equipment, while molecular diagnostics require less time and labor. The Loop mediated isothermal amplification assay (LAMP) is rapid, sensitive and specific assay and requires no specialized equipment. In the present study, we developed a LAMP assay for rapid as well as specific detection of Bacillus anthracis. The optimized assay produced positive results with the Sterne strain and one field isolate of B. anthracis and, negative results with other bacteria of the same and different genera within 2 h. Sensitivity was 500 fg of total DNA of B. anthracis, which was 100 times more sensitive than conventional PCR. The present study also demonstrated that the simple method of total DNA extraction by repeated boiling and freezing will not adversely affect the LAMP results. In conclusion, the optimized LAMP assay is a promising tool for the specific, sensitive, less time-consuming diagnosis for anthrax causing bacteria and also, for detecting the virulence of suspected B. anthracis cultures.


Assuntos
Antraz , Bacillus anthracis , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , Animais , Antraz/diagnóstico , Bacillus anthracis/genética , Bacillus anthracis/isolamento & purificação , Humanos , Sensibilidade e Especificidade
7.
Proc Natl Acad Sci U S A ; 115(44): 11226-11231, 2018 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-30262649

RESUMO

Accurate translation of the genetic code is critical to ensure expression of proteins with correct amino acid sequences. Certain tRNAs can cause a shift out of frame (i.e., frameshifting) due to imbalances in tRNA concentrations, lack of tRNA modifications or insertions or deletions in tRNAs (called frameshift suppressors). Here, we determined the structural basis for how frameshift-suppressor tRNASufA6 (a derivative of tRNAPro) reprograms the mRNA frame to translate a 4-nt codon when bound to the bacterial ribosome. After decoding at the aminoacyl (A) site, the crystal structure of the anticodon stem-loop of tRNASufA6 bound in the peptidyl (P) site reveals ASL conformational changes that allow for recoding into the +1 mRNA frame. Furthermore, a crystal structure of full-length tRNASufA6 programmed in the P site shows extensive conformational rearrangements of the 30S head and body domains similar to what is observed in a translocation intermediate state containing elongation factor G (EF-G). The 30S movement positions tRNASufA6 toward the 30S exit (E) site disrupting key 16S rRNA-mRNA interactions that typically define the mRNA frame. In summary, this tRNA-induced 30S domain change in the absence of EF-G causes the ribosome to lose its grip on the mRNA and uncouples the canonical forward movement of the tRNAs during elongation.


Assuntos
Mutação da Fase de Leitura/genética , Mudança da Fase de Leitura do Gene Ribossômico/genética , RNA de Transferência/genética , Ribossomos/genética , Bactérias/genética , Códon/genética , Fator G para Elongação de Peptídeos/genética , Biossíntese de Proteínas/genética , RNA Mensageiro/genética , RNA Ribossômico 16S/genética , Fases de Leitura/genética
8.
Am J Respir Cell Mol Biol ; 63(4): 519-530, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32628869

RESUMO

KD025 is a ROCK2 inhibitor currently being tested in clinical trials for the treatment of fibrotic lung diseases. The therapeutic effects of KD025 are partly due to its inhibition of profibrotic pathways and fat metabolism. However, whether KD025 affects pulmonary microvascular endothelial cell (PMVEC) function is unknown, despite evidence that alveolar-capillary membrane disruption constitutes major causes of death in fibrotic lung diseases. We hypothesized that KD025 regulates PMVEC metabolism, pH, migration, and survival, a series of interrelated functional characteristics that determine pulmonary barrier integrity. We used PMVECs isolated from Sprague Dawley rats. KD025 dose-dependently decreased lactate production and glucose consumption. The inhibitory effect of KD025 was more potent compared with other metabolic modifiers, including 2-deoxy-glucose, extracellular acidosis, dichloroacetate, and remogliflozin. Interestingly, KD025 increased oxidative phosphorylation, whereas 2-deoxy-glucose did not. KD025 also decreased intracellular pH and induced a compensatory increase in anion exchanger 2. KD025 inhibited PMVEC migration, but fasudil (nonspecific ROCK inhibitor) did not. We tested endothelial permeability in vivo using Evans Blue dye in the bleomycin pulmonary fibrosis model. Baseline permeability was decreased in KD025-treated animals independent of bleomycin treatment. Under hypoxia, KD025 increased PMVEC necrosis as indicated by increased lactate dehydrogenase release and propidium iodide uptake and decreased ATP; it did not affect Annexin V binding. ROCK2 knockdown had no effect on PMVEC metabolism, pH, and migration, but it increased nonapoptotic caspase-3 activity. Together, we report that KD025 promotes oxidative phosphorylation; decreases glycolysis, intracellular pH, and migration; and strengthens pulmonary barrier integrity in a ROCK2-independent manner.


Assuntos
Permeabilidade Capilar/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Pulmão/efeitos dos fármacos , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/análogos & derivados , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/farmacologia , Trifosfato de Adenosina/metabolismo , Animais , Anexina A5/metabolismo , Movimento Celular/efeitos dos fármacos , Desoxiglucose/metabolismo , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Glicólise/efeitos dos fármacos , Concentração de Íons de Hidrogênio , L-Lactato Desidrogenase/metabolismo , Pulmão/metabolismo , Masculino , Fosforilação Oxidativa/efeitos dos fármacos , Propídio/farmacologia , Ratos , Ratos Endogâmicos F344 , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Quinases Associadas a rho/metabolismo
9.
Indian J Microbiol ; 59(3): 261-265, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31388202

RESUMO

In current study, we performed a comparative study on bacterial load, total coliform counts and type of organisms present in pre- and post-treated wastewater samples from municipal wastewater treatment plant of Pune, India. In addition, we also studied the antibiotic resistance profiling and role of the selected treatment plant in spread of antibiotic resistance in the environment. Data showed that total 30 different bacterial species from 18-different genera were present in untreated wastewater while only 9 species from 6-different genera were present in post-treated effluent. Furthermore, pre-treated wastewater sample contains wide range of organisms with high levels of antibiotic resistance while bacterial load reduced drastically and pathogens were absent from post-treated effluent.

10.
Indian J Clin Biochem ; 33(1): 38-45, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29371768

RESUMO

Recent studies have been noted that the erythrocytes from Type II diabetic patients show significantly altered structural and functional characteristics along with the changed intracellular concentrations of glycolytic intermediates. More recent studies from our laboratory have shown that the activities of enzymes of glycolytic pathway changed significantly in RBCs from Type II diabetic patients. In particular the levels of lactate dehydrogenase (LDH) increased significantly. Lactic acidosis is an established feature of diabetes and LDH plays a crucial role in conversion of pyruvate to lactate and reportedly, the levels of lactate are significantly high which is consistent with our observation on increased levels of LDH. Owing to this background, we examined the role of erythrocyte LDH in lactic acidosis by studying its kinetics properties in Type II diabetic patients. Km, Vmax and apparent catalytic efficiency were determined using pyruvate and NADH as the substrates. With pyruvate as the substrate the Km values were comparable but Vmax increased significantly in the diabetic group. With NADH as the substrate the enzyme activity of the diabetic group resolved in two components as against a single component in the controls. The Apparent Kcat and Kcat/Km values for pyruvate increased in the diabetic group. The Ki for pyruvate increased by two fold for the enzyme from diabetic group with a marginal decrease in Ki for NADH. The observed changes in catalytic attributes are conducive to enable the enzyme to carry the reaction in forward direction towards conversion of pyruvate to lactate leading to lactic acidosis.

11.
J Biol Chem ; 290(47): 28156-28165, 2015 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-26432638

RESUMO

Double-stranded RNA (dsRNA)-activated protein kinase (PKR) is an important component of the innate immune system that presents a crucial first line of defense against viral infection. PKR has a modular architecture comprising a regulatory N-terminal dsRNA binding domain and a C-terminal kinase domain interposed by an unstructured ∼80-residue interdomain linker (IDL). Guided by sequence alignment, we created IDL deletions in human PKR (hPKR) and regulatory/kinase domain swap human-rat chimeric PKRs to assess the contributions of each domain and the IDL to regulation of the kinase activity by RNA. Using circular dichroism spectroscopy, limited proteolysis, kinase assays, and isothermal titration calorimetry, we show that each PKR protein is properly folded with similar domain boundaries and that each exhibits comparable polyinosinic-cytidylic (poly(rI:rC)) dsRNA activation profiles and binding affinities for adenoviral virus-associated RNA I (VA RNAI) and HIV-1 trans-activation response (TAR) RNA. From these results we conclude that the IDL of PKR is not required for RNA binding or mediating changes in protein conformation or domain interactions necessary for PKR regulation by RNA. In contrast, inhibition of rat PKR by VA RNAI and TAR RNA was found to be weaker than for hPKR by 7- and >300-fold, respectively, and each human-rat chimeric domain-swapped protein showed intermediate levels of inhibition. These findings indicate that PKR sequence or structural elements in the kinase domain, present in hPKR but absent in rat PKR, are exploited by viral non-coding RNAs to accomplish efficient inhibition of PKR.


Assuntos
RNA não Traduzido/fisiologia , eIF-2 Quinase/metabolismo , Sequência de Aminoácidos , Ativação Enzimática , Deleção de Genes , Humanos , Dados de Sequência Molecular , Homologia de Sequência de Aminoácidos , eIF-2 Quinase/antagonistas & inibidores , eIF-2 Quinase/química
12.
PLoS Biol ; 11(12): e1001727, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24311987

RESUMO

The 3-O-sulfotransferase (3-OST) family catalyzes rare modifications of glycosaminoglycan chains on heparan sulfate proteoglycans, yet their biological functions are largely unknown. Knockdown of 3-OST-7 in zebrafish uncouples cardiac ventricular contraction from normal calcium cycling and electrophysiology by reducing tropomyosin4 (tpm4) expression. Normal 3-OST-7 activity prevents the expansion of BMP signaling into ventricular myocytes, and ectopic activation of BMP mimics the ventricular noncontraction phenotype seen in 3-OST-7 depleted embryos. In 3-OST-7 morphants, ventricular contraction can be rescued by overexpression of tropomyosin tpm4 but not by troponin tnnt2, indicating that tpm4 serves as a lynchpin for ventricular sarcomere organization downstream of 3-OST-7. Contraction can be rescued by expression of 3-OST-7 in endocardium, or by genetic loss of bmp4. Strikingly, BMP misregulation seen in 3-OST-7 morphants also occurs in multiple cardiac noncontraction models, including potassium voltage-gated channel gene, kcnh2, affected in Romano-Ward syndrome and long-QT syndrome, and cardiac troponin T gene, tnnt2, affected in human cardiomyopathies. Together these results reveal 3-OST-7 as a key component of a novel pathway that constrains BMP signaling from ventricular myocytes, coordinates sarcomere assembly, and promotes cardiac contractile function.


Assuntos
Proteínas Morfogenéticas Ósseas/fisiologia , Contração Miocárdica/fisiologia , Sulfotransferases/fisiologia , Proteínas de Peixe-Zebra/fisiologia , Potenciais de Ação/fisiologia , Animais , Técnicas de Silenciamento de Genes , Desenvolvimento Muscular/fisiologia , Miócitos Cardíacos/fisiologia , Sarcômeros/fisiologia , Transdução de Sinais/fisiologia , Tropomiosina/fisiologia , Peixe-Zebra
13.
Indian J Clin Biochem ; 31(3): 321-5, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27382204

RESUMO

The activity of enzymes of glycolysis has been studied in erythrocytes from type-II diabetic patients in comparison with control. RBC lysate was the source of enzymes. In the diabetics the hexokinase (HK) activity increased 50 % while activities of phosphoglucoisomerase (PGI), phosphofructokinase (PFK) and aldolase (ALD) decreased by 37, 75 and 64 % respectively but were still several folds higher than that of HK. Hence, it is possible that in the diabetic erythrocytes the process of glycolysis could proceed in an unimpaired or in fact may be augmented due to increased levels of G6P. The lactate dehydrogenase (LDH) activity was comparatively high in both the groups; the diabetic group showed 85 % increase. In control group the HK, PFK and ALD activities showed strong positive correlation with blood sugar level while PGI activity did not show any correlation. In the diabetic group only PFK activity showed positive correlation. The LDH activity only in the control group showed positive correlation with marginal increase with increasing concentrations of glucose.

14.
J Biol Chem ; 289(33): 23233-23245, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24970889

RESUMO

Virus-associated RNA I (VA RNAI) is a short (∼160-nucleotide) non-coding RNA transcript employed by adenoviruses to subvert the innate immune system protein double-stranded RNA-activated protein kinase (PKR). The central domain of VA RNAI is proposed to contain a complex tertiary structure that contributes to its optimal inhibitory activity against PKR. Here we use a combination of VA RNAI mutagenesis, structural analyses, as well as PKR activity and binding assays to dissect this tertiary structure and assess its functional role. Our results support the existence of a pH- and Mg(2+)-dependent tertiary structure involving pseudoknot formation within the central domain. Unexpectedly, this structure appears to play no direct role in PKR inhibition. Deletion of central domain sequences within a minimal but fully active construct lacking the tertiary structure reveals a crucial role in PKR binding and inhibition for nucleotides in the 5' half of the central domain. Deletion of the central domain 3' half also significantly impacts activity but appears to arise indirectly by reducing its capacity to assist in optimally presenting the 5' half sequence. Collectively, our results identify regions of VA RNAI critical for PKR inhibition and reveal that the requirements for an effective RNA inhibitor of PKR are simpler than appreciated previously.


Assuntos
Adenoviridae/química , Conformação de Ácido Nucleico , RNA Viral/química , eIF-2 Quinase/antagonistas & inibidores , Adenoviridae/genética , Adenoviridae/metabolismo , Concentração de Íons de Hidrogênio , Magnésio/química , Mutagênese , RNA Viral/genética , RNA Viral/metabolismo , eIF-2 Quinase/química , eIF-2 Quinase/genética , eIF-2 Quinase/metabolismo
15.
Antimicrob Agents Chemother ; 59(5): 2807-16, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25733511

RESUMO

Methylation of bacterial 16S rRNA within the ribosomal decoding center confers exceptionally high resistance to aminoglycoside antibiotics. This resistance mechanism is exploited by aminoglycoside producers for self-protection while functionally equivalent methyltransferases have been acquired by human and animal pathogenic bacteria. Here, we report structural and functional analyses of the Sorangium cellulosum So ce56 aminoglycoside resistance-conferring methyltransferase Kmr. Our results demonstrate that Kmr is a 16S rRNA methyltransferase acting at residue A1408 to confer a canonical aminoglycoside resistance spectrum in Escherichia coli. Kmr possesses a class I methyltransferase core fold but with dramatic differences in the regions which augment this structure to confer substrate specificity in functionally related enzymes. Most strikingly, the region linking core ß-strands 6 and 7, which forms part of the S-adenosyl-l-methionine (SAM) binding pocket and contributes to base flipping by the m(1)A1408 methyltransferase NpmA, is disordered in Kmr, correlating with an exceptionally weak affinity for SAM. Kmr is unexpectedly insensitive to substitutions of residues critical for activity of other 16S rRNA (A1408) methyltransferases and also to the effects of by-product inhibition by S-adenosylhomocysteine (SAH). Collectively, our results indicate that adoption of a catalytically competent Kmr conformation and binding of the obligatory cosubstrate SAM must be induced by interaction with the 30S subunit substrate.


Assuntos
Aminoglicosídeos/farmacologia , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , RNA Ribossômico 16S/genética , Farmacorresistência Bacteriana/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Proteínas de Escherichia coli/genética
16.
Biologicals ; 42(6): 316-21, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25151655

RESUMO

A protective antigen (PA) based coagglutination test was optimized in the present study for the specific and sensitive identification of bacteria causing anthrax in a cost effective and less risky manner. The test showed 100% specificity and sensitivity up to 9 × 10(3) formalinized vegetative cells or 11 ng of PA. The optimized test also detected anthrax toxin directly from the serum as well as blood of anthrax infected animals indicating the potential application for direct diagnosis of anthrax under field conditions.


Assuntos
Antraz/diagnóstico , Antígenos de Bactérias/química , Bacillus anthracis/isolamento & purificação , Toxinas Bacterianas/química , Animais , Coagulação Sanguínea , Western Blotting , Cobaias , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , Coelhos , Proteínas Recombinantes/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Células-Tronco
17.
Lett Appl Microbiol ; 58(5): 401-7, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24286182

RESUMO

UNLABELLED: A specific latex agglutination test (LAT) based on anti-PA (protective antigen) antibodies having detection limit of 5 × 10(4) formalin treated Bacillus anthracis cells or 110 ng of PA was optimized in this study. The optimized LAT could detect anthrax toxin in whole blood as well as in serum from the animal models of anthrax infection. The protocol is a simple and promising method for the specific detection of bacteria causing anthrax under routine laboratory, as well as in field, conditions without any special equipments or expertise. SIGNIFICANCE AND IMPACT OF THE STUDY: The article presents the first report of a latex agglutination test for the specific identification of the cultures of bacteria causing anthrax. As the test is targeting one of anthrax toxic protein (PA), this can also be used to determine virulence of suspected organisms. At the same time, the same LAT can be used directly on whole blood or sera samples under field conditions for the specific diagnosis of anthrax.


Assuntos
Antraz/diagnóstico , Antraz/microbiologia , Antígenos de Bactérias/genética , Bacillus anthracis/isolamento & purificação , Toxinas Bacterianas/genética , Testes de Fixação do Látex/métodos , Animais , Antraz/imunologia , Bacillus anthracis/genética , Bacillus cereus , Cobaias , Testes de Fixação do Látex/economia , Limite de Detecção , Coelhos , Proteínas Recombinantes/genética
18.
Indian J Physiol Pharmacol ; 58(3): 302-5, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25906617

RESUMO

A cross-sectional type of observational study was conducted at 7 various stone crusher units on 120 male stone crushers and 120 healthy male controls. Values of FEF25-27% and PEFR were recorded on computerized spirometer and were compared between workers and age matched controls group. The value of FEF25-75% and PEFR was significantly reduced in stone crushers as compared to controls. Also as the duration of exposure increases the values of flow rates goes on decreasing among workers. Stone crushers of Marathwada region of Maharashtra exposed to silica dust were prone to develop lung disorders as indicated by reduced value of FEF25-75% and PEFR.


Assuntos
Exposição Ocupacional/efeitos adversos , Testes de Função Respiratória , Dióxido de Silício/efeitos adversos , Adulto , Estudos Transversais , Humanos , Masculino , Fluxo Máximo Médio Expiratório , Pessoa de Meia-Idade , Pico do Fluxo Expiratório
19.
Bioinformation ; 20(5): 430-433, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39132225

RESUMO

Post-vaccination myocarditis is usually moderate and transient, recovering quickly with conservative treatment. Therefore, it is of interest to assess for arrhythmia after CoViD-19 vaccination among Indians. We looked for ECG abnormalities in a small cohort of 50 participants after 52 weeks after receiving the Oxford/AstraZeneca CoViD-19 vaccination. Data shows that post-vaccination myocarditis is typically mild and transient, with most cases resolving swiftly through conservative management. Thus, it is unlikely that this vaccine will induce severe arrhythmias or life-threatening cardiac events in the general population.

20.
Transplant Proc ; 56(1): 97-104, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38216361

RESUMO

AIMS AND BACKGROUND: To describe the prevalence of IgA deposits (IgAD) in renal allografts in a cohort of renal transplant recipients and to analyze their management strategies and histopathology. To assess graft function and proteinuria after 1 year of follow-up. MATERIALS AND METHODS: A prospective longitudinal follow-up study was carried out in VPS Lakeshore Hospital and Research Centre, Kochi, Kerala, over a period of 5 years (July 2015 to June 2020). Kidney transplant recipients with allograft biopsies that reported IgAD on immunofluorescence were included in the study. Light microscopy and immunofluorescence studies were performed. Mesangial hypercellularity (M); segmental glomerulosclerosis (S); endocapillary hypercellularity (E); tubular atrophy/interstitial fibrosis (T); crescents (C) (MEST-C) Scoring was done in patients with pathogenic IgAD. Treatment strategies included increased baseline steroid dosage, rituximab administration, and plasma exchange. Clinical details and management strategies were analyzed, and patients were followed up for 1 year after diagnosis. Changes in graft function (S. Creatinine) and proteinuria (Urine Protein/Creatinine ratio) were analyzed. Clinico-pathologic correlation with the MEST-C scores was also done. RESULTS: Out of 1036 kidney transplants done in the study period, 760 graft biopsies were performed. Sixty-four cases had post-transplant deposition of IgA (8%). The mean age was 45 ± 11.25SD years. The study had 51 men and 13 women. Induction immunosuppression comprised rabbit antithymocyte globulin in 29 (45%) patients and basiliximab in 35 (54%). Maintenance immunosuppression in all comprised tacrolimus, mycophenolate mofetil, and steroids. There were 2 groups: group A (pathogenic IgAD) and group B (incidental IgAD). Group A had 46 cases (71.9%), out of which 8 had "active" IgA nephropathy (endocapillary proliferation, crescents, and IgA vasculitis), and 38 had "inactive" IgAD. In patients with active deposits, 3 had cellular crescents (18%, 30%, and 23%), all 8 had endocapillary proliferation, and 2 had vasculitis. Group B had 18 cases (28.1%), comprising T cell-mediated rejections (5), antibody-mediated rejection (8), BK virus nephropathy (1), and interstitial fibrosis and tubular atrophy (4). In group A, 22 (47.8%) presented with graft dysfunction, 8 (17.3%) with isolated proteinuria, and 14 (30.4%) patients presented with a combination. Two (4.3%) patients had neither. Fourteen (30.4%) patients presented within 1 month of renal transplant. In patients of group A, at the end of 1 year of treatment, the mean S. Creatinine reduced to 1.68 mg/dL from 1.84 mg/dL, and the mean protein/creatinine ratio reduced from 1.2 to 0.5 (±1.17). In patients with "active IgA" lesions, at the end of 1 year of treatment, the mean S. Creatinine increased slightly to 1.68 mg/dL (±0.47SD) from 1.48 mg/dL (±0.52SD), and the mean protein/creatinine ratio reduced from 2.32 (±1.56SD) to 1.05 (±1.70SD). In the 16 patients with IgAD and proteinuria, at the end of 1 year of treatment, the mean S. Creatinine decreased to 1.41 ± 0.32 SD mg/dL from 1.47±0.37SD mg/dL and the mean protein/creatinine ratio reduced from 1.12 ± 1.31 SD to 0.39±0.75 SD. In the remaining 22 patients with acute tubular injury, at the end of 1 year, the mean S. Creatinine decreased to 1.920.32 SD mg/dL from 2.10.8SD mg/dL, and the mean protein/creatinine ratio reduced from 1.1 ± 1.31 SD to 0.66 ± 1.45 SD. In the MEST-C scoring analysis, all scores were 0 in 20 (43.4%) biopsies, only M1 score in 11 (23.9%) biopsies, only E1 score in 10 biopsies (21.7%), S1 in 13 (28.2%) cases. CONCLUSION: Immunoglobulin A deposits occur commonly after transplant; these may represent recurrence, de novo IgA, or donor-derived IgAD. Although commonly benign, some may cause significant graft dysfunction and graft loss. IgAD can present as varying combinations of graft dysfunction and proteinuria. Active IgA pathologies may occur early in the post-transplant course, may have significant graft dysfunction, and need proactive management. There is a correlation between segmental sclerosis and proteinuria. Evidence for the efficacy of Rituximab, plasma exchange, and prolonged courses of steroids is wanting; however, some benefits are possible. Long-term follow-up is essential.


Assuntos
Glomerulonefrite por IGA , Transplante de Rim , Masculino , Humanos , Feminino , Adulto , Pessoa de Meia-Idade , Transplante de Rim/efeitos adversos , Rituximab/uso terapêutico , Estudos Prospectivos , Creatinina , Seguimentos , Rim/patologia , Glomerulonefrite por IGA/patologia , Proteinúria/etiologia , Imunoglobulina A , Esteroides/uso terapêutico , Fibrose , Aloenxertos/patologia , Atrofia/patologia , Biópsia/efeitos adversos
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