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1.
J Exp Bot ; 73(14): 5067-5083, 2022 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-35552406

RESUMO

Jasmonate (JA) is an important hormone involved in regulating diverse responses to environmental factors as well as growth and development, and its signalling is influenced by other hormones such as ethylene (ET). However, our understanding of the regulatory relationship between the JA and ET signalling pathways is limited. In this study, we isolated an Arabidopsis JA-hypersensitive mutant, jah3 (jasmonate hypersensitive3)-1. Map-based cloning revealed that the JAH3 gene corresponds to At4g16535. JAH3 encodes a protein of unknown function whose amino acid sequence has similarity to leukocyte receptor cluster-like protein. The mutation in jah3-1 is caused by a single nucleotide change from A to T at position 220 of 759 bp. Using CRISPR-Cas9, we generated a second allele, jah3-2, that encodes a truncated protein. Both of these loss-of-function alleles resulted in hypersensitivity to JA, ET-induced root growth inhibition, and accelerated dark-induced senescence. Double mutant analyses employing coronatine insensitive 1 (coi1) and ethylene insensitive 3 (ein3) mutants (jah3 coi1 and jah3 ein3) demonstrated that the hypersensitive phenotypes of the jah3 mutants are mediated by JA and ET signalling components COI1 and EIN3. Therefore, we propose that JAH3 is a negative regulator of both JA and ET signalling.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ciclopentanos/metabolismo , Etilenos/metabolismo , Regulação da Expressão Gênica de Plantas , Mutação , Oxilipinas/metabolismo
2.
Proc Natl Acad Sci U S A ; 116(21): 10510-10517, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31061116

RESUMO

Mycobacterium tuberculosis (Mtb) killed more people in 2017 than any other single infectious agent. This dangerous pathogen is able to withstand stresses imposed by the immune system and tolerate exposure to antibiotics, resulting in persistent infection. The global tuberculosis (TB) epidemic has been exacerbated by the emergence of mutant strains of Mtb that are resistant to frontline antibiotics. Thus, both phenotypic drug tolerance and genetic drug resistance are major obstacles to successful TB therapy. Using a chemical approach to identify compounds that block stress and drug tolerance, as opposed to traditional screens for compounds that kill Mtb, we identified a small molecule, C10, that blocks tolerance to oxidative stress, acid stress, and the frontline antibiotic isoniazid (INH). In addition, we found that C10 prevents the selection for INH-resistant mutants and restores INH sensitivity in otherwise INH-resistant Mtb strains harboring mutations in the katG gene, which encodes the enzyme that converts the prodrug INH to its active form. Through mechanistic studies, we discovered that C10 inhibits Mtb respiration, revealing a link between respiration homeostasis and INH sensitivity. Therefore, by using C10 to dissect Mtb persistence, we discovered that INH resistance is not absolute and can be reversed.


Assuntos
Antituberculosos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Isoniazida , Mycobacterium tuberculosis/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos
3.
RNA ; 25(9): 1177-1191, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31221726

RESUMO

Uridine insertion deletion editing in kinetoplastid protozoa requires a complex machinery, a primary component of which is the RNA editing substrate binding complex (RESC). RESC contains two modules termed GRBC (guide RNA binding complex) and REMC (RNA editing mediator complex), although how interactions between these modules and their mRNA and gRNA binding partners are controlled is not well understood. Here, we demonstrate that the ARM/HEAT repeat containing RESC protein, MRB10130, controls REMC association with mRNA- and gRNA-loaded GRBC. High-throughput sequencing analyses show that MRB10130 functions in both initiation and 3' to 5' progression of editing through gRNA-defined domains. Editing intermediates that accumulate upon MRB10130 depletion significantly intersect those in cells depleted of another RESC organizer, MRB7260, but are distinct from those in cells depleted of specific REMC proteins. We present a model in which MRB10130 coordinates numerous protein-protein and protein-RNA interactions during editing progression.


Assuntos
Edição de RNA/genética , Animais , Linhagem Celular , Domínios e Motivos de Interação entre Proteínas/genética , Proteínas de Protozoários/genética , Interferência de RNA/fisiologia , RNA Guia de Cinetoplastídeos/genética , RNA Mensageiro/genética , RNA de Protozoário/genética , Trypanosoma brucei brucei/genética , Uridina/genética
4.
Mol Plant Microbe Interact ; 33(8): 1059-1071, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32407150

RESUMO

Modification of host hormone biology is a common strategy used by plant pathogens to promote disease. For example, the bacterial pathogen strain Pseudomonas syringae DC3000 (PtoDC3000) produces the plant hormone auxin (indole-3-acetic acid [IAA]) to promote PtoDC3000 growth in plant tissue. Previous studies suggest that auxin may promote PtoDC3000 pathogenesis through multiple mechanisms, including both suppression of salicylic acid (SA)-mediated host defenses and via an unknown mechanism that appears to be independent of SA. To test if host auxin signaling is important during pathogenesis, we took advantage of Arabidopsis thaliana lines impaired in either auxin signaling or perception. We found that disruption of auxin signaling in plants expressing an inducible dominant axr2-1 mutation resulted in decreased bacterial growth and that this phenotype was suppressed by introducing the sid2-2 mutation, which impairs SA synthesis. Thus, host auxin signaling is required for normal susceptibility to PtoDC3000 and is involved in suppressing SA-mediated defenses. Unexpectedly, tir1 afb1 afb4 afb5 quadruple-mutant plants lacking four of the six known auxin coreceptors that exhibit decreased auxin perception, supported increased levels of bacterial growth. This mutant exhibited elevated IAA levels and reduced SA-mediated defenses, providing additional evidence that auxin promotes disease by suppressing host defense. We also investigated the hypothesis that IAA promotes PtoDC3000 virulence through a direct effect on the pathogen and found that IAA modulates expression of virulence genes, both in culture and in planta. Thus, in addition to suppressing host defenses, IAA acts as a microbial signaling molecule that regulates bacterial virulence gene expression.


Assuntos
Arabidopsis/microbiologia , Ácidos Indolacéticos/metabolismo , Doenças das Plantas/microbiologia , Imunidade Vegetal , Pseudomonas syringae/patogenicidade , Virulência , Regulação da Expressão Gênica de Plantas , Mutação , Pseudomonas syringae/genética , Ácido Salicílico/metabolismo , Transdução de Sinais
6.
mSphere ; 9(2): e0063123, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38299856

RESUMO

Gregory Harrison is a bacteriologist researching essential pathways in bacteria as potential therapeutic targets. In this mSphere of Influence article, he reflects on a series of studies that employ complementary genetic approaches to define the crucial role of AsmA-family proteins in transporting phospholipids between the inner and outer membranes of Gram-negative bacteria. The authors of these three studies identify this family of lipid transporters through the means of bacterial genetics, answering a long-standing question in bacterial physiology, and serving as a reminder that a well-designed genetic strategy can go a long way in uncovering new biology.


Assuntos
Bactérias Gram-Negativas , Proteínas de Membrana Transportadoras , Transporte Biológico , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Bactérias Gram-Negativas/genética
7.
mBio ; 15(3): e0296823, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38294237

RESUMO

Of the approximately 10 million cases of Mycobacterium tuberculosis (Mtb) infections each year, over 10% are resistant to the frontline antibiotic isoniazid (INH). INH resistance is predominantly caused by mutations that decrease the activity of the bacterial enzyme KatG, which mediates the conversion of the pro-drug INH to its active form INH-NAD. We previously discovered an inhibitor of Mtb respiration, C10, that enhances the bactericidal activity of INH, prevents the emergence of INH-resistant mutants, and re-sensitizes a collection of INH-resistant mutants to INH through an unknown mechanism. To investigate the mechanism of action of C10, we exploited the toxicity of high concentrations of C10 to select for resistant mutants. We discovered two mutations that confer resistance to the disruption of energy metabolism and allow for the growth of Mtb in high C10 concentrations, indicating that growth inhibition by C10 is associated with inhibition of respiration. Using these mutants as well as direct inhibitors of the Mtb electron transport chain, we provide evidence that inhibition of energy metabolism by C10 is neither sufficient nor necessary to potentiate killing by INH. Instead, we find that C10 acts downstream of INH-NAD synthesis, causing Mtb to become particularly sensitive to inhibition of the INH-NAD target, InhA, without changing the concentration of INH-NAD or the activity of InhA, the two predominant mechanisms of potentiating INH. Our studies revealed that there exists a vulnerability in Mtb that can be exploited to render Mtb sensitive to otherwise subinhibitory concentrations of InhA inhibitor.IMPORTANCEIsoniazid (INH) is a critical frontline antibiotic to treat Mycobacterium tuberculosis (Mtb) infections. INH efficacy is limited by its suboptimal penetration of the Mtb-containing lesion and by the prevalence of clinical INH resistance. We previously discovered a compound, C10, that enhances the bactericidal activity of INH, prevents the emergence of INH-resistant mutants, and re-sensitizes a set of INH-resistant mutants to INH. Resistance is typically mediated by katG mutations that decrease the activation of INH, which is required for INH to inhibit the essential enzyme InhA. Our current work demonstrates that C10 re-sensitizes INH-resistant katG-hypomorphs without enhancing the activation of INH. We furthermore show that C10 causes Mtb to become particularly vulnerable to InhA inhibition without compromising InhA activity on its own. Therefore, C10 represents a novel strategy to curtail the development of INH resistance and to sensitize Mtb to sub-lethal doses of INH, such as those achieved at the infection site.


Assuntos
Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Humanos , Isoniazida/farmacologia , Mycobacterium tuberculosis/genética , Antituberculosos/farmacologia , Farmacorresistência Bacteriana/genética , Proteínas de Bactérias/genética , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Mutação , Catalase/genética , Testes de Sensibilidade Microbiana
8.
bioRxiv ; 2023 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-36798348

RESUMO

Of the approximately 10 million cases of Mycobacterium tuberculosis (Mtb) infections each year, over 10% are resistant to the frontline antibiotic isoniazid (INH). INH resistance is predominantly caused by mutations that decrease the activity of the bacterial enzyme KatG, which mediates conversion of the pro-drug INH to its active form INH-NAD. We previously discovered an inhibitor of Mtb respiration, C10, that enhances the bactericidal activity of INH, prevents the emergence of INH-resistant mutants, and re-sensitizes a collection of INH-resistant mutants to INH through an unknown mechanism. To investigate the mechanism of action of C10, we exploited the toxicity of high concentrations of C10 to select for resistant mutants. We discovered two mutations that confer resistance to the disruption of energy metabolism and allow for growth of Mtb in high C10 concentrations, indicating that growth inhibition by C10 is associated with inhibition of respiration. Using these mutants as well as direct inhibitors of the Mtb electron transport chain, we provide evidence that inhibition of energy metabolism by C10 is neither sufficient nor necessary to potentiate killing by INH. Instead, we find that C10 acts downstream of INH-NAD synthesis, causing Mtb to become particularly sensitive to inhibition of the INH-NAD target, InhA, without changing the concentration of INH-NAD or the activity of InhA, the two predominant mechanisms of potentiating INH. Our studies revealed that there exists a vulnerability in Mtb that can be exploited to render Mtb sensitive to otherwise subinhibitory concentrations of InhA inhibitor.

9.
J Med Chem ; 66(16): 11056-11077, 2023 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-37485869

RESUMO

Mycobacterium tuberculosis (Mtb) drug resistance poses an alarming threat to global tuberculosis control. We previously reported that C10, a ring-fused thiazolo-2-pyridone, inhibits Mtb respiration, blocks biofilm formation, and restores the activity of the antibiotic isoniazid (INH) in INH-resistant Mtb isolates. This discovery revealed a new strategy to address INH resistance. Expanding upon this strategy, we identified C10 analogues with improved potency and drug-like properties. By exploring three heterocycle spacers (oxadiazole, 1,2,3-triazole, and isoxazole) on the ring-fused thiazolo-2-pyridone scaffold, we identified two novel isoxazoles, 17h and 17j. 17h and 17j inhibited Mtb respiration and biofilm formation more potently with a broader therapeutic window, were better potentiators of INH-mediated inhibition of an INH-resistant Mtb mutant, and more effectively inhibited intracellular Mtb replication than C10. The (-)17j enantiomer showed further enhanced activity compared to its enantiomer and the 17j racemic mixture. Our potent second-generation C10 analogues offer promise for therapeutic development against drug-resistant Mtb.


Assuntos
Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Humanos , Isoniazida/farmacologia , Isoniazida/uso terapêutico , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Farmacorresistência Bacteriana , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Isoxazóis/farmacologia , Testes de Sensibilidade Microbiana , Proteínas de Bactérias
10.
Front Cell Infect Microbiol ; 12: 958555, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36072222

RESUMO

Treatment of Mycobacterium tuberculosis (Mtb) infections is particularly arduous. One challenge to effectively treating tuberculosis is that drug efficacy in vivo often fails to match drug efficacy in vitro. This is due to multiple reasons, including inadequate drug concentrations reaching Mtb at the site of infection and physiological changes of Mtb in response to host derived stresses that render the bacteria more tolerant to antibiotics. To more effectively and efficiently treat tuberculosis, it is necessary to better understand the physiologic state of Mtb that promotes drug tolerance in the host. Towards this end, multiple studies have converged on bacterial central carbon metabolism as a critical contributor to Mtb drug tolerance. In this review, we present the evidence that changes in central carbon metabolism can promote drug tolerance, depending on the environment surrounding Mtb. We posit that these metabolic pathways could be potential drug targets to stymie the development of drug tolerance and enhance the efficacy of current antimicrobial therapy.


Assuntos
Mycobacterium tuberculosis , Tuberculose dos Linfonodos , Carbono/metabolismo , Tolerância a Medicamentos , Humanos , Redes e Vias Metabólicas
11.
Biomolecules ; 12(2)2022 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-35204839

RESUMO

BACKGROUND: HAVcR-1 has been linked to cancer aetiology and may regulate junctional complexes, with its role in prostate cancer still unexplored. This study aims to investigate the expression of HAVcR-1 in prostate cancer samples and the exploration of the cellular/molecular impact of HAVcR-1. METHODS: Levels of HAVcR-1 ectodomain in the serum of prostate cancer patients were compared to healthy controls, and assessed as the total protein and gene expression of HAVcR-1 and tissues sections. The manipulation of HAVcR-1 levels within prostate cancer cell lines determined changes in cell behaviour using in vitro cell models and barrier function assays. Protein/phosphoprotein levels were assessed using Western blotting. RESULTS: Levels of HAVcR-1 ectodomain from serum were decreased in patients with prostate cancer. Ectodomain levels correlated with the Gleason score. Histologically, the total protein/gene expression of HAVcR-1 was overexpressed in prostate cancer. The overexpression of HAVcR-1 in prostate cancer cell lines resulted in key changes in cell behaviour and the phosphorylation of ß-catenin with a concurrent decrease in membranous E-cadherin, increased nuclear ß-catenin and increased cyclin D1 protein expression, which were associated with HGF-promoted changes in the barrier function. CONCLUSIONS: HAVcR-1 expression and ectodomain release coincides with the presence of prostate cancer; thus, indicating HAVcR-1 as a potential biomarker to aid in diagnostics, and implicating HAVcR-1 in the dysregulation of junctional complexes.


Assuntos
Receptor Celular 1 do Vírus da Hepatite A , Fator de Crescimento de Hepatócito , Junções Intercelulares , Neoplasias da Próstata , Caderinas , Linhagem Celular Tumoral , Humanos , Junções Intercelulares/fisiologia , Masculino , Neoplasias da Próstata/genética , Receptores Virais , beta Catenina
12.
Sci Rep ; 11(1): 1523, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452380

RESUMO

Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), is a major health threat listed among the top 10 causes of death worldwide. Treatment of multidrug-resistant Mtb requires use of additional second-line drugs that prolong the treatment process and result in higher death rates. Our team previously identified a 2-pyridone molecule (C10) that blocks tolerance to the first-line drug isoniazid at C10 concentrations that do not inhibit bacterial growth. Here, we discovered that the genes rv3160c and rv3161c are highly induced by C10, which led us to investigate them as potential targets. We show that Rv3160c acts as a TetR-like transcriptional repressor binding to a palindromic sequence located in the rv3161c promoter. We also demonstrate that C10 interacts with Rv3160c, inhibiting its binding to DNA. We deleted the rv3161c gene, coding for a putative oxygenase, to investigate its role in drug and stress sensitivity as well as C10 activity. This Δrv3161c strain was more tolerant to isoniazid and lysozyme than wild type Mtb. However, this tolerance could still be blocked by C10, suggesting that C10 functions independently of Rv3161c to influence isoniazid and lysozyme sensitivity.


Assuntos
Resistência Microbiana a Medicamentos/genética , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/metabolismo , Antituberculosos/farmacologia , Proteínas de Bactérias/metabolismo , Expressão Gênica/genética , Regulação Bacteriana da Expressão Gênica/genética , Isoniazida/farmacologia , Oxigenases/metabolismo , Ligação Proteica , Proteínas Repressoras/metabolismo , Tetraciclina/farmacologia , Fatores de Transcrição/metabolismo , Tuberculose/metabolismo , Tuberculose/microbiologia , Tuberculose Resistente a Múltiplos Medicamentos/metabolismo , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia
13.
Annu Rev Pathol ; 16: 377-408, 2021 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-33497258

RESUMO

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), remains a leading cause of death due to infection in humans. To more effectively combat this pandemic, many aspects of TB control must be developed, including better point of care diagnostics, shorter and safer drug regimens, and a protective vaccine. To address all these areas of need, better understanding of the pathogen, host responses, and clinical manifestations of the disease is required. Recently, the application of cutting-edge technologies to the study of Mtb pathogenesis has resulted in significant advances in basic biology, vaccine development, and antibiotic discovery. This leaves us in an exciting era of Mtb research in which our understanding of this deadly infection is improving at a faster rate than ever, and renews hope in our fight to end TB. In this review, we reflect on what is known regarding Mtb pathogenesis, highlighting recent breakthroughs that will provide leverage for the next leaps forward in the field.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Antituberculosos/uso terapêutico , Humanos , Mycobacterium tuberculosis/patogenicidade
14.
BMJ Case Rep ; 13(9)2020 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-32878830

RESUMO

A 79-year-old man developed a spontaneous cholecystocutaneous fistula 12 months after an initial episode of acute cholecystitis. A laparoscopic cholecystectomy procedure was twice abandoned due to extensive adhesions and active disease, limiting safe dissection of Calot's triangle. Abdominal collections formed and a spontaneous cholecystocutaneous fistula developed. Imaging revealed an 11 cm calculus and erosion of the fundus of the gall bladder through the sheath. Definitive management was achieved with a laparoscopic assisted open cholecystectomy.


Assuntos
Fístula Biliar/cirurgia , Colecistectomia Laparoscópica/métodos , Colecistite Aguda/cirurgia , Colecistolitíase/cirurgia , Conversão para Cirurgia Aberta , Fístula Cutânea/cirurgia , Idoso , Fístula Biliar/etiologia , Colecistite Aguda/etiologia , Colecistolitíase/complicações , Fístula Cutânea/etiologia , Vesícula Biliar/diagnóstico por imagem , Vesícula Biliar/cirurgia , Humanos , Imageamento por Ressonância Magnética , Masculino , Fatores de Tempo , Tempo para o Tratamento , Tomografia Computadorizada por Raios X , Resultado do Tratamento
15.
PLoS One ; 14(2): e0212700, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30794664

RESUMO

Drought stress has been identified as the major environmental factor limiting soybean [Glycine max (L.) Merr.] yield worldwide. Current breeding efforts in soybean largely focus on identifying genotypes with high seed yield and drought tolerance. Water use efficiency (WUE) that results in greater yield per unit rainfall is an important parameter in determining crop yields in many production systems, and is often related with crop drought tolerance. Even though roots are major plant organs that perceive and respond to drought stress, their utility in improving soybean yield and WUE under different environmental and management conditions are largely unclear. The objectives of this research was to evaluate soybean cultivars and breeding and germplasm lines for yield, WUE, root penetrability of hardpan, and root morphology. Field experiments were conducted at two locations in South Carolina (southeastern United States) during the 2017 cropping season to test the genotypes for yield and root morphology under irrigated and non-irrigated conditions. Two independent controlled-environmental experiments were conducted to test the genotypes for WUE and root penetrability of synthetic hardpans. The slow wilting lines NTCPR94-5157 and N09-13890 had equal or greater yield than the checks- cultivar NC-Raleigh and the elite South Carolina breeding line SC07-1518RR, under irrigated and non-irrigated conditions. The high yielding genotypes NTCPR94-5157, N09-13890, and SC07-1518RR exhibited root parsimony (reduced root development). This supported the recent hypothesis in literature that root parsimony would have adaptational advantage to improve yield under high input field conditions. The high yielding genotypes NTCPR94-5157, N09-13890, NC-Raleigh, and SC07-1518RR and a cultivar Boggs (intermediate in yield) possessed high WUE and had increased root penetrability of hardpans. These genotypes offer useful genetic materials for soybean breeding programs for improving yield, drought tolerance, and/or hardpan penetrability.


Assuntos
Genótipo , Glycine max/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Característica Quantitativa Herdável , Água/metabolismo , Produção Agrícola , Raízes de Plantas/genética , Glycine max/genética , Especificidade da Espécie
16.
mSphere ; 4(5)2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31511370

RESUMO

Antibiotic resistance is a global crisis that threatens our ability to treat bacterial infections, such as tuberculosis, caused by Mycobacterium tuberculosis Of the 10 million cases of tuberculosis in 2017, approximately 19% of new cases and 43% of previously treated cases were caused by strains of M. tuberculosis resistant to at least one frontline antibiotic. There is a clear need for new therapies that target these genetically resistant strains. Here, we report the discovery of a new series of antimycobacterial compounds, 4-amino-thieno[2,3-d]pyrimidines, that potently inhibit the growth of M. tuberculosis To elucidate the mechanism by which these compounds inhibit M. tuberculosis, we selected for mutants resistant to a representative 4-amino-thieno[2,3-d]pyrimidine and sequenced these strains to identify the mutations that confer resistance. We isolated a total of 12 resistant mutants, each of which harbored a nonsynonymous mutation in the gene qcrB, which encodes a subunit of the electron transport chain (ETC) enzyme cytochrome bc1 oxidoreductase, leading us to hypothesize that 4-amino-thieno[2,3-d]pyrimidines target this enzyme complex. We found that addition of 4-amino-thieno[2,3-d]pyrimidines to M. tuberculosis cultures resulted in a decrease in ATP levels, supporting our model that these compounds inhibit the M. tuberculosis ETC. Furthermore, 4-amino-thieno[2,3-d]pyrimidines had enhanced activity against a mutant of M. tuberculosis deficient in cytochrome bd oxidase, which is a hallmark of cytochrome bc1 inhibitors. Therefore, 4-amino-thieno[2,3-d]pyrimidines represent a novel series of QcrB inhibitors that build on the growing number of chemical scaffolds that are able to inhibit the mycobacterial cytochrome bc1 complex.IMPORTANCE The global tuberculosis (TB) epidemic has been exacerbated by the rise in drug-resistant TB cases worldwide. To tackle this crisis, it is necessary to identify new vulnerable drug targets in Mycobacterium tuberculosis, the causative agent of TB, and develop compounds that can inhibit the bacterium through novel mechanisms of action. The QcrB subunit of the electron transport chain enzyme cytochrome bc1 has recently been validated to be a potential drug target. In the current work, we report the discovery of a new class of QcrB inhibitors, 4-amino-thieno[2,3-d]pyrimidines, that potently inhibit M. tuberculosis growth in vitro These compounds are chemically distinct from previously reported QcrB inhibitors, and therefore, 4-amino-thieno[2,3-d]pyrimidines represent a new scaffold that can be exploited to inhibit this drug target.


Assuntos
Antibióticos Antituberculose/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Mycobacterium tuberculosis/efeitos dos fármacos , Pirimidinas/farmacologia , Antibióticos Antituberculose/química , Proteínas de Bactérias/genética , Descoberta de Drogas , Complexo III da Cadeia de Transporte de Elétrons/genética , Testes de Sensibilidade Microbiana , Mutação , Mycobacterium tuberculosis/genética , Pirimidinas/química
17.
J Cell Biochem ; 105(1): 41-52, 2008 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-18442037

RESUMO

Claudin-16 (Paracellin-1) is a transmembrane tight junction (TJ) protein originally described as having a critical role in the re-absorption of magnesium and calcium in the kidney. This study examined expression of Claudin-16 in human breast cells and tissues to identify a possible link between expression and aggressiveness in cells and between Claudin-16 levels and patient prognosis. Insertion of the Claudin-16 gene into MDA-MB-231 human breast cancer cells resulted in cells that were significantly less motile and invasive in behavior, with increased adhesion to matrix. These cells also exhibited significantly increased TJ functionality and "tighter" colony morphology. Moreover, growth rates were reduced in both in vitro and in vivo assays (P < 0.002). Frozen sections from breast cancer primary tumors (matched tumor 124 and background 33) were immuno-stained. RNA was reverse transcribed and analyzed by Q-PCR (standardized using beta-actin, normalized with cytokeratin-19 levels). Levels of expression of Claudin-16 were significantly decreased in node positive tumors compared to negative (P = 0.016). Expression was significantly lower in patients with node positive tumors (P = 0.016) and in those who had died from breast cancer or had general poor prognosis (P < 0.015). Immunohistochemical staining showed decreased expression of Claudin-16 in tumor sections (P < 0.00001). In conclusion, forced expression of Claudin-16 in breast cancer cells resulted in a less aggressive phenotype and reduced in vivo tumor volume. Claudin-16 expression was reduced in human breast cancer, particularly in patients with aggressive tumors and high mortality. This suggests that Claudin-16 plays a role beyond that of an initial metastasis repressor in this cancer type.


Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proteínas de Membrana/metabolismo , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Claudinas , Progressão da Doença , Células Epiteliais/metabolismo , Seguimentos , Regulação Neoplásica da Expressão Gênica , Humanos , Proteínas de Membrana/genética , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Estadiamento de Neoplasias , Fenótipo , RNA Mensageiro/genética , Fatores de Tempo , Resultado do Tratamento
18.
Home Healthc Nurse ; 26(4): 222-9, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18408515

RESUMO

The Chronic Care Model (CCM) developed by is an influential and accepted guide for the care of patients with chronic disease. Wagner acknowledges a current healthcare focus on acute care needs that often circumvents chronic care coordination. He identifies the need for a "division of labor" to assist the primary care physician with this neglected function. This article posits that the role of chronic care coordination assistance and disease management fits within the purview of home healthcare and should be central to home health chronic care delivery. An expanded Home-Based Chronic Care Model (HBCCM) is described that builds on Wagner's model and integrates salient theories from fields beyond medicine. The expanded model maximizes the potential for disease self-management success and is intended to provide a foundation for home health's integral role in chronic disease management.


Assuntos
Doença Crônica/enfermagem , Enfermagem em Saúde Comunitária/organização & administração , Serviços de Assistência Domiciliar/organização & administração , Assistência de Longa Duração/organização & administração , Modelos de Enfermagem , Modelos Organizacionais , Administração de Caso/organização & administração , Análise Custo-Benefício , Sistemas de Apoio a Decisões Clínicas , Gerenciamento Clínico , Necessidades e Demandas de Serviços de Saúde , Humanos , Liderança , Sistemas Computadorizados de Registros Médicos , Papel do Profissional de Enfermagem , Médicos de Família/organização & administração , Guias de Prática Clínica como Assunto , Atenção Primária à Saúde/organização & administração , Autocuidado , Gestão da Qualidade Total/organização & administração
19.
PLoS One ; 13(7): e0200463, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29995945

RESUMO

Root systems that improve resource uptake and penetrate compacted soil (hardpan) are important for improving soybean (Glycine max L. Merr.) productivity in optimal and sub-optimal environments. The objectives of this research were to evaluate a soybean germplasm collection of 49 genotypes for root traits, determine whether root traits are related with plant height, shoot dry weight, chlorophyll index, and seed size, and identify genotypes that can penetrate a hardpan. Plants were maintained under optimal growth conditions in a greenhouse. Single plants were grown in mesocosms, constructed of two stacked columns (top and bottom columns had 25 and 46 cm height, respectively, and 15 cm inside diameter) with a 2-cm thick wax layer (synthetic hardpan; penetration resistance, 1.5 MPa at 30°C) in between. Plants were harvested at 42 days after planting. Significant genetic variability was observed for root traits in the soybean germplasm collection, and genotypes that penetrated the synthetic hardpan were identified. Genotypes NTCPR94-5157, NMS4-1-83, and N09-13128 were ranked high and PI 424007 and R01-581F were ranked low for most root traits. Shoot dry weight and chlorophyll index were positively related with total root length, surface area, and volume, and fine root length (Correlation coefficient, r ≥ 0.60 and P-value < 0.0001 for shoot dry weight and r ≥ 0.37 and P-value < 0.01 for chlorophyll index]. Plant height was negatively correlated with total root surface area, total root volume, and average root diameter (|r| ≥ 0.29, P-value < 0.05). Seed size was not correlated with any root traits. The genetic variability identified in this research for root traits and penetration are critical for soybean improvement programs in choosing genotypes with improved root characteristics to increase yield in stressful or optimum environments.


Assuntos
Glycine max/anatomia & histologia , Glycine max/genética , Melhoramento Vegetal , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/genética , Produtos Agrícolas/anatomia & histologia , Produtos Agrícolas/genética , Ambiente Controlado , Fenótipo
20.
Crit Rev Oncol Hematol ; 46(2): 165-86, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12711360

RESUMO

CD44 is a cell adhesion molecule that was traditionally known as 'homing receptor'. This molecule is known to interact with the ezrin family (ERM family) members and form a complex that plays diverse roles within both normal and abnormal cells, particularly cancer cells. CD44 and ezrin and their respective complex have properties suggesting that they may be important in the process of tumour-endothelium interactions, cell migrations, cell adhesion, tumour progression and metastasis. This article reviews the role of CD44, ezrin family and the CD44/ezrin complex in cancer cells and their clinical impact in patients with cancer.


Assuntos
Receptores de Hialuronatos/fisiologia , Metástase Neoplásica/fisiopatologia , Proteínas de Neoplasias/fisiologia , Fosfoproteínas/fisiologia , Adesão Celular/fisiologia , Movimento Celular/fisiologia , Proteínas do Citoesqueleto , Regulação Neoplásica da Expressão Gênica , Humanos , Receptores de Hialuronatos/química , Receptores de Hialuronatos/genética , Substâncias Macromoleculares , Modelos Moleculares , Família Multigênica , Proteínas de Neoplasias/química , Proteínas de Neoplasias/genética , Neoplasias/genética , Neoplasias/metabolismo , Neovascularização Patológica/fisiopatologia , Fosfoproteínas/química , Fosfoproteínas/genética , Relação Estrutura-Atividade
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