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1.
Nature ; 597(7876): 430-434, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34471289

RESUMO

Extracellular electron transfer by Geobacter species through surface appendages known as microbial nanowires1 is important in a range of globally important environmental phenomena2, as well as for applications in bio-remediation, bioenergy, biofuels and bioelectronics. Since 2005, these nanowires have been thought to be type 4 pili composed solely of the PilA-N protein1. However, previous structural analyses have demonstrated that, during extracellular electron transfer, cells do not produce pili but rather nanowires made up of the cytochromes OmcS2,3 and OmcZ4. Here we show that Geobacter sulfurreducens binds PilA-N to PilA-C to assemble heterodimeric pili, which remain periplasmic under nanowire-producing conditions that require extracellular electron transfer5. Cryo-electron microscopy revealed that C-terminal residues of PilA-N stabilize its copolymerization with PilA-C (to form PilA-N-C) through electrostatic and hydrophobic interactions that position PilA-C along the outer surface of the filament. PilA-N-C filaments lack π-stacking of aromatic side chains and show a conductivity that is 20,000-fold lower than that of OmcZ nanowires. In contrast with surface-displayed type 4 pili, PilA-N-C filaments show structure, function and localization akin to those of type 2 secretion pseudopili6. The secretion of OmcS and OmcZ nanowires is lost when pilA-N is deleted and restored when PilA-N-C filaments are reconstituted. The substitution of pilA-N with the type 4 pili of other microorganisms also causes a loss of secretion of OmcZ nanowires. As all major phyla of prokaryotes use systems similar to type 4 pili, this nanowire translocation machinery may have a widespread effect in identifying the evolution and prevalence of diverse electron-transferring microorganisms and in determining nanowire assembly architecture for designing synthetic protein nanowires.


Assuntos
Fímbrias Bacterianas/química , Fímbrias Bacterianas/metabolismo , Geobacter , Nanofios , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Biopolímeros , Condutividade Elétrica , Proteínas de Fímbrias/química , Proteínas de Fímbrias/metabolismo , Geobacter/citologia , Geobacter/metabolismo , Multimerização Proteica
2.
Nature ; 579(7797): 123-129, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32103176

RESUMO

A mosaic of cross-phylum chemical interactions occurs between all metazoans and their microbiomes. A number of molecular families that are known to be produced by the microbiome have a marked effect on the balance between health and disease1-9. Considering the diversity of the human microbiome (which numbers over 40,000 operational taxonomic units10), the effect of the microbiome on the chemistry of an entire animal remains underexplored. Here we use mass spectrometry informatics and data visualization approaches11-13 to provide an assessment of the effects of the microbiome on the chemistry of an entire mammal by comparing metabolomics data from germ-free and specific-pathogen-free mice. We found that the microbiota affects the chemistry of all organs. This included the amino acid conjugations of host bile acids that were used to produce phenylalanocholic acid, tyrosocholic acid and leucocholic acid, which have not previously been characterized despite extensive research on bile-acid chemistry14. These bile-acid conjugates were also found in humans, and were enriched in patients with inflammatory bowel disease or cystic fibrosis. These compounds agonized the farnesoid X receptor in vitro, and mice gavaged with the compounds showed reduced expression of bile-acid synthesis genes in vivo. Further studies are required to confirm whether these compounds have a physiological role in the host, and whether they contribute to gut diseases that are associated with microbiome dysbiosis.


Assuntos
Ácidos e Sais Biliares/biossíntese , Ácidos e Sais Biliares/química , Metabolômica , Microbiota/fisiologia , Animais , Ácidos e Sais Biliares/metabolismo , Ácido Cólico/biossíntese , Ácido Cólico/química , Ácido Cólico/metabolismo , Fibrose Cística/genética , Fibrose Cística/metabolismo , Fibrose Cística/microbiologia , Vida Livre de Germes , Humanos , Doenças Inflamatórias Intestinais/genética , Doenças Inflamatórias Intestinais/metabolismo , Doenças Inflamatórias Intestinais/microbiologia , Camundongos , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo
3.
Dev Biol ; 513: 50-62, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38492873

RESUMO

The voltage gated (Kv) slow-inactivating delayed rectifier channel regulates the development of hollow organs of the zebrafish. The functional channel consists of the tetramer of electrically active Kcnb1 (Kv2.1) subunits and Kcng4b (Kv6.4) modulatory or electrically silent subunits. The two mutations in zebrafish kcng4b gene - kcng4b-C1 and kcng4b-C2 (Gasanov et al., 2021) - have been studied during ear development using electrophysiology, developmental biology and in silico structural modelling. kcng4b-C1 mutation causes a C-terminal truncation characterized by mild Kcng4b loss-of-function (LOF) manifested by failure of kinocilia to extend and formation of ectopic otoliths. In contrast, the kcng4b-C2-/- mutation causes the C-terminal domain to elongate and the ectopic seventh transmembrane (TM) domain to form, converting the intracellular C-terminus to an extracellular one. Kcng4b-C2 acts as a Kcng4b gain-of-function (GOF) allele. Otoliths fail to develop and kinocilia are reduced in kcng4b-C2-/-. These results show that different mutations of the silent subunit Kcng4 can affect the activity of the Kv channel and cause a wide range of developmental defects.


Assuntos
Orelha , Canais de Ânion Dependentes de Voltagem , Proteínas de Peixe-Zebra , Peixe-Zebra , Animais , Orelha/embriologia , Mutação/genética , Peixe-Zebra/genética , Peixe-Zebra/embriologia , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , Canais de Ânion Dependentes de Voltagem/genética , Canais de Ânion Dependentes de Voltagem/metabolismo
4.
Biochem Biophys Res Commun ; 706: 149735, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38461647

RESUMO

Enolase-1 (Eno1) plays a critical role in regulating glucose metabolism; however, its specific impact on pancreatic islet ß-cells remains elusive. This study aimed to provide a preliminary exploration of Eno1 function in pancreatic islet ß-cells. The findings revealed that the expression of ENO1 mRNA in type 2 diabetes donors was significantly increased and positively correlated with HbA1C and negatively correlated with insulin gene expression. A high level of Eno1 in human insulin-secreting rat INS-1832/13 cells with co-localization with intracellular insulin proteins was accordingly observed. Silencing of Eno1 using siRNA or inhibiting Eno1 protein activity with an Eno1 antagonist significantly reduced insulin secretion and insulin content in ß-cells, while the proinsulin/insulin content ratio remained unchanged. This reduction in ß-cells function was accompanied by a notable decrease in intracellular ATP and mitochondrial cytochrome C levels. Overall, our findings confirm that Eno1 regulates the insulin secretion process, particularly glucose metabolism and ATP production in the ß-cells. The mechanism primarily involves its influence on insulin production, suggesting that Eno1 represents a potential target for ß-cell protection and diabetes treatment.


Assuntos
Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Humanos , Ratos , Animais , Insulina/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Células Secretoras de Insulina/metabolismo , Fosfopiruvato Hidratase/genética , Fosfopiruvato Hidratase/metabolismo , Glucose/metabolismo , Expressão Gênica , Trifosfato de Adenosina/metabolismo
5.
Scand J Immunol ; : e13373, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38757311

RESUMO

The IFIH1 gene, encoding melanoma differentiation-associated protein 5 (MDA5), is an indispensable innate immune regulator involved in the early detection of viral infections. Previous studies described MDA5 dysregulation in weakened immunological responses, and increased susceptibility to microbial infections and autoimmune disorders. Monoallelic gain-of-function of the IFIH1 gene has been associated with multisystem disorders, namely Aicardi-Goutieres and Singleton-Merten syndromes, while biallelic loss causes immunodeficiency. In this study, nine patients suffering from recurrent infections, inflammatory diseases, severe COVID-19 or multisystem inflammatory syndrome in children (MIS-C) were identified with putative loss-of-function IFIH1 variants by whole-exome sequencing. All patients revealed signs of lymphopaenia and an increase in inflammatory markers, including CRP, amyloid A, ferritin and IL-6. One patient with a pathogenic homozygous variant c.2807+1G>A was the most severe case showing immunodeficiency and glomerulonephritis. The c.1641+1G>C variant was identified in the heterozygous state in patients suffering from periodic fever, COVID-19 or MIS-C, while the c.2016delA variant was identified in two patients with inflammatory bowel disease or MIS-C. There was a significant association between IFIH1 monoallelic loss of function and susceptibility to infections in males. Expression analysis showed that PBMCs of one patient with a c.2016delA variant had a significant decrease in ISG15, IFNA and IFNG transcript levels, compared to normal PBMCs, upon stimulation with Poly(I:C), suggesting that MDA5 receptor truncation disrupts the immune response. Our findings accentuate the implication of rare monogenic IFIH1 loss-of-function variants in altering the immune response, and severely predisposing patients to inflammatory and infectious diseases, including SARS-CoV-2-related disorders.

6.
Mol Cell ; 63(2): 191-205, 2016 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-27397687

RESUMO

Small-RNA (sRNA)-guided transcriptional gene silencing by Argonaute (Ago)-containing complexes is fundamental to genome integrity and epigenetic inheritance. The RNA cleavage ("Slicer") activity of Argonaute has been implicated in both sRNA maturation and target RNA cleavage. Typically, Argonaute slices and releases the passenger strand of duplex sRNA to generate active silencing complexes, but it remains unclear whether slicing of target nascent RNAs, or other RNAi components, also contributes to downstream transcriptional silencing. Here, we develop a strategy for loading the fission yeast Ago1 with a single-stranded sRNA guide, which bypasses the requirement for slicer activity in generation of active silencing complexes. We show that slicer-defective Ago1 can mediate secondary sRNA generation, H3K9 methylation, and silencing similar to or better than wild-type and associates with chromatin more efficiently. The results define an ancient and minimal sRNA-mediated chromatin silencing mechanism, which resembles the germline-specific sRNA-dependent transcriptional silencing pathways in Drosophila and mammals.


Assuntos
Proteínas Argonautas/metabolismo , Montagem e Desmontagem da Cromatina , Heterocromatina/metabolismo , Interferência de RNA , RNA Fúngico/metabolismo , RNA Interferente Pequeno/biossíntese , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/enzimologia , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Proteínas Argonautas/genética , Metilação de DNA , Endorribonucleases/genética , Endorribonucleases/metabolismo , Regulação Fúngica da Expressão Gênica , Histonas/metabolismo , RNA Fúngico/genética , RNA Interferente Pequeno/genética , Schizosaccharomyces/genética , Proteínas de Schizosaccharomyces pombe/genética , Transcrição Gênica
7.
Am J Med Genet A ; 191(11): 2723-2727, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37668308

RESUMO

Missense variants in the RNF13 gene have been previously known to cause congenital microcephaly, epileptic encephalopathy, blindness, and failure to thrive through a gain-of-function disease mechanism. Here, we identify a nonsense variant, expected to result in protein truncation, in a similarly affected patient. We show that this nonsense variant, residing in the terminal exon, is likely to escape nonsense-mediated decay while removing a critical region for protein function, thus resulting in a gain-of-function effect. We review the literature and disease databases and identify several other affected individuals with overlapping phenotypes carrying distinct truncating variants in the terminal exon upstream of the putative critical region. Furthermore, we analyze truncating variants from the general population, namely, the Genome Aggregation Database (gnomAD), and provide additional evidence supporting our hypothesis, and ruling out haploinsufficiency as an alternative disease mechanism. In summary, our case report, literature review, and analysis of disease and population databases strongly support the hypothesis that heterozygous gain-of-function variants in a critical region of RNF13 cause congenital microcephaly, epileptic encephalopathy, blindness, and failure to thrive.


Assuntos
Microcefalia , Espasmos Infantis , Humanos , Microcefalia/genética , Insuficiência de Crescimento/genética , Mutação com Ganho de Função , Espasmos Infantis/genética , Cegueira , Ubiquitina-Proteína Ligases/genética
8.
Nat Chem Biol ; 16(10): 1136-1142, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32807967

RESUMO

Multifunctional living materials are attractive due to their powerful ability to self-repair and replicate. However, most natural materials lack electronic functionality. Here we show that an electric field, applied to electricity-producing Geobacter sulfurreducens biofilms, stimulates production of cytochrome OmcZ nanowires with 1,000-fold higher conductivity (30 S cm-1) and threefold higher stiffness (1.5 GPa) than the cytochrome OmcS nanowires that are important in natural environments. Using chemical imaging-based multimodal nanospectroscopy, we correlate protein structure with function and observe pH-induced conformational switching to ß-sheets in individual nanowires, which increases their stiffness and conductivity by 100-fold due to enhanced π-stacking of heme groups; this was further confirmed by computational modeling and bulk spectroscopic studies. These nanowires can transduce mechanical and chemical stimuli into electrical signals to perform sensing, synthesis and energy production. These findings of biologically produced, highly conductive protein nanowires may help to guide the development of seamless, bidirectional interfaces between biological and electronic systems.


Assuntos
Proteínas de Bactérias/metabolismo , Estimulação Elétrica , Geobacter/fisiologia , Nanofios/química , Proteínas de Bactérias/genética , Condutividade Elétrica , Fenômenos Eletrofisiológicos
9.
J Thromb Thrombolysis ; 53(1): 158-166, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34097227

RESUMO

In major/life-threatening bleeding, administration of timely and appropriate reversal agents is imperative to reduce morbidity and mortality. Due to complexities associated with the use of reversal agents, a clinical pharmacist-driven anticoagulation reversal program (ARP) was developed. The goal of this program was to ensure appropriateness of reversal agents based on the clinical scenario, optimize selection and avoid unintended consequences. This study describes the impact of a pharmacist-driven anticoagulation program on patient outcomes and cost. A single center retrospective chart review of adult patients whom the ARP was consulted from October 2018 to January 2020 was performed. Patients were included in the efficacy analysis if they were > 18 years of age and presented with acute bleeding. Patients were excluded from the efficacy analysis if the recommended reversal agent was not administered, if a repeat head CT was not available for patients who presented with intracranial hemorrhage (ICH), or if the patient was not bleeding. All patients were included in the economic evaluation. The primary outcome was the percentage of patients who achieved effective hemostasis within 24 h of anticoagulation reversal. Secondary outcomes include incidence of thromboembolic events, in-hospital mortality, and cost avoidance. One hundred twenty-one patients were evaluated by the ARP with 92 patients included in the efficacy analysis. The primary sites of bleeding were ICH in 46% and gastrointestinal (GI) in 29%. Hemostasis was achieved in 84% of patients. Thrombotic events occurred in 7.4% of patients and in-hospital mortality was 26.4%. Total cost avoidance was $1,005,871.78. To our knowledge, this is the first study to evaluate the impact of a pharmacist-driven ARP on clinical and economic outcomes. Implementation of a pharmacist-driven ARP was associated with favorable outcomes and cost savings.


Assuntos
Reversão da Anticoagulação , Farmacêuticos , Centros Médicos Acadêmicos , Adulto , Anticoagulantes/efeitos adversos , Fatores de Coagulação Sanguínea , Fator Xa , Inibidores do Fator Xa/efeitos adversos , Humanos , Estudos Retrospectivos
10.
Oral Dis ; 28(4): 1094-1103, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-33615634

RESUMO

OBJECTIVE: Oral submucous fibrosis (OSF) is a debilitating potentially malignant condition of the buccal cavity characterized by extensive extracellular matrix deposition resulting in stiffness and trismus. As OSF is a progressive disease, we hypothesized that there would be extensive epigenetic changes in OSF tissues. MATERIALS AND METHODS: Using the Infinium HumanMethylation450 BeadChip Array, we analyzed gross DNA methylation changes in seven OSF tissues compared to five controls. Comparison with transcriptomic data and pathway analyses was conducted to find commonly regulated genes. RESULTS: A total of 3,294 differentially methylated regions mapping to 857 genes were identified. Comparison with transcriptome data revealed 38 downregulated-hypermethylated genes and 55 hypomethylated-upregulated genes. Using methylation-specific and qRT-PCR, aberrant hypomethylation and increased expression of FGF13, RPS6KA3, and ACSL4 genes were confirmed. Pathways involved in insulin signaling, ubiquitin-mediated proteolysis, nicotine addiction, and RAS/MAPK pathways were dysregulated, among others. Intriguingly, numerous genes located on the X chromosome were dysregulated in OSF tissues as the transcript for XIST gene was downregulated due to hypermethylation of the XIST promoter. CONCLUSIONS: This study highlights global epigenetic dysregulation of tissues of the oral cavity in OSF patients and hints at possible X chromosomal dysregulation, previously not implicated in the pathogenesis of OSF.


Assuntos
Metilação de DNA , Fibrose Oral Submucosa , Areca , Epigênese Genética , Humanos , Mucosa Bucal/patologia , Fibrose Oral Submucosa/genética , Fibrose Oral Submucosa/patologia , Regiões Promotoras Genéticas/genética
11.
PLoS Pathog ; 15(11): e1008149, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31682637

RESUMO

Attachment is a necessary first step in bacterial commitment to surface-associated behaviors that include colonization, biofilm formation, and host-directed virulence. The Gram-negative opportunistic pathogen Pseudomonas aeruginosa can initially attach to surfaces via its single polar flagellum. Although many bacteria quickly detach, some become irreversibly attached and express surface-associated structures, such as Type IV pili, and behaviors, including twitching motility and biofilm initiation. P. aeruginosa that lack the GTPase FlhF assemble a randomly placed flagellum that is motile; however, we observed that these mutant bacteria show defects in biofilm formation comparable to those seen for non-motile, aflagellate bacteria. This phenotype was associated with altered behavior of ΔflhF bacteria immediately following surface-attachment. Forward and reverse genetic screens led to the discovery that FlhF interacts with FimV to control flagellar rotation at a surface, and implicated cAMP signaling in this pathway. Although cAMP controls many transcriptional programs in P. aeruginosa, known targets of this second messenger were not required to modulate flagellar rotation in surface-attached bacteria. Instead, alterations in switching behavior of the motor appeared to result from direct or indirect effects of cAMP on switch complex proteins and/or the stators associated with them.


Assuntos
Proteínas de Bactérias/metabolismo , Fímbrias Bacterianas/fisiologia , Flagelos/fisiologia , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Pseudomonas aeruginosa/fisiologia , Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , AMP Cíclico/metabolismo , Regulação Bacteriana da Expressão Gênica , Proteínas Monoméricas de Ligação ao GTP/genética , Mutação , Fenótipo , Transdução de Sinais , Virulência
12.
Proc Natl Acad Sci U S A ; 115(49): E11523-E11531, 2018 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-30442666

RESUMO

The SMCR8-WDR41-C9ORF72 complex is a regulator of autophagy and lysosomal function. Autoimmunity and inflammatory disease have been ascribed to loss-of-function mutations of Smcr8 or C9orf72 in mice. In humans, autoimmunity has been reported to precede amyotrophic lateral sclerosis caused by mutations of C9ORF72 However, the cellular and molecular mechanisms underlying autoimmunity and inflammation caused by C9ORF72 or SMCR8 deficiencies remain unknown. Here, we show that splenomegaly, lymphadenopathy, and activated circulating T cells observed in Smcr8-/- mice were rescued by triple knockout of the endosomal Toll-like receptors (TLRs) TLR3, TLR7, and TLR9. Myeloid cells from Smcr8-/- mice produced excessive inflammatory cytokines in response to endocytosed TLR3, TLR7, or TLR9 ligands administered in the growth medium and in response to TLR2 or TLR4 ligands internalized by phagocytosis. These defects likely stem from prolonged TLR signaling caused by accumulation of LysoTracker-positive vesicles and by delayed phagosome maturation, both of which were observed in Smcr8-/- macrophages. Smcr8-/- mice also showed elevated susceptibility to dextran sodium sulfate-induced colitis, which was not associated with increased TLR3, TLR7, or TLR9 signaling. Deficiency of WDR41 phenocopied loss of SMCR8. Our findings provide evidence that excessive endosomal TLR signaling resulting from prolonged ligand-receptor contact causes inflammatory disease in SMCR8-deficient mice.


Assuntos
Proteína C9orf72/metabolismo , Proteínas de Transporte/metabolismo , Inflamação/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Receptores Toll-Like/metabolismo , Animais , Doenças Autoimunes/genética , Doenças Autoimunes/metabolismo , Proteínas Relacionadas à Autofagia , Proteína C9orf72/genética , Proteínas de Transporte/genética , Colite/induzido quimicamente , Sulfato de Dextrana , Regulação da Expressão Gênica , Hematopoese/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Camundongos Knockout , Mutação , Transdução de Sinais/imunologia , Receptores Toll-Like/genética
13.
Pain Med ; 21(12): 3314-3319, 2020 12 25.
Artigo em Inglês | MEDLINE | ID: mdl-32869096

RESUMO

INTRODUCTION: Treatment options are limited for nonsurgical chronic refractory cases of adhesive capsulitis. We describe a novel percutaneous tenotomy technique for coracohumeral ligament interruption with cadaveric validation. OBJECTIVE: The objective of this study was to describe and validate a novel technique for percutaneous interruption of the coracohumeral ligament. DESIGN: Cadaveric study. SETTING: Academic tertiary care center. METHODS: Eight cadavers underwent ultrasound (US)-guided percutaneous incision of the coracohumeral (CHL) ligament. Performance of the procedure requires that the practitioner make oscillatory motions with a needle that uses ultrasound energy to cut through tissue. Each pass removes a pinhead-sized amount of tissue. The number of passes and the cutting time are recorded during the procedure. As a standard for this procedure does not exist, the authors created their own based on the preclinical information presented here. Postprocedure dissection was performed to assess the extent of CHL interruption and injury to surrounding tissue. RESULTS: The average resection time was seven minutes, requiring 500 passes. The technique described in this paper completely interrupted the CHL in all subjects. Cadaveric analysis demonstrated interruption of the CHL with respect to control shoulders requiring an average of seven minutes of cutting time and ∼500 micro-perforations. CONCLUSION: US-guided percutaneous CHL ligament sectioning is possible with a commercially available ultrasonic probe.


Assuntos
Bursite , Articulação do Ombro , Bursite/diagnóstico por imagem , Bursite/cirurgia , Cadáver , Humanos , Ligamentos Articulares/diagnóstico por imagem , Ligamentos Articulares/cirurgia , Ultrassonografia
14.
J Bacteriol ; 201(13)2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31010901

RESUMO

The bacterial flagellum is a sophisticated self-assembling nanomachine responsible for motility in many bacterial pathogens, including Pseudomonas aeruginosa, Vibrio spp., and Salmonella enterica The bacterial flagellum has been studied extensively in the model systems Escherichia coli and Salmonella enterica serovar Typhimurium, yet the range of variation in flagellar structure and assembly remains incompletely understood. Here, we used cryo-electron tomography and subtomogram averaging to determine in situ structures of polar flagella in P. aeruginosa and peritrichous flagella in S Typhimurium, revealing notable differences between these two flagellar systems. Furthermore, we observed flagellar outer membrane complexes as well as many incomplete flagellar subassemblies, which provide additional insight into mechanisms underlying flagellar assembly and loss in both P. aeruginosa and S Typhimurium.IMPORTANCE The bacterial flagellum has evolved as one of the most sophisticated self-assembled molecular machines, which confers locomotion and is often associated with virulence of bacterial pathogens. Variation in species-specific features of the flagellum, as well as in flagellar number and placement, results in structurally distinct flagella that appear to be adapted to the specific environments that bacteria encounter. Here, we used cutting-edge imaging techniques to determine high-resolution in situ structures of polar flagella in Pseudomonas aeruginosa and peritrichous flagella in Salmonella enterica serovar Typhimurium, demonstrating substantial variation between flagella in these organisms. Importantly, we observed novel flagellar subassemblies and provided additional insight into the structural basis of flagellar assembly and loss in both P. aeruginosa and S Typhimurium.


Assuntos
Microscopia Crioeletrônica , Tomografia com Microscopia Eletrônica , Flagelos/ultraestrutura , Pseudomonas aeruginosa/citologia , Salmonella typhimurium/citologia , Proteínas de Bactérias/metabolismo , Flagelos/genética , Regulação Bacteriana da Expressão Gênica , Pseudomonas aeruginosa/genética , Salmonella typhimurium/genética
15.
PLoS Pathog ; 13(8): e1006594, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28854278

RESUMO

Type IVa pili (T4P) are bacterial surface structures that enable motility, adhesion, biofilm formation and virulence. T4P are assembled by nanomachines that span the bacterial cell envelope. Cycles of T4P assembly and retraction, powered by the ATPases PilB and PilT, allow bacteria to attach to and pull themselves along surfaces, so-called "twitching motility". These opposing ATPase activities must be coordinated and T4P assembly limited to one pole for bacteria to show directional movement. How this occurs is still incompletely understood. Herein, we show that the c-di-GMP binding protein FimX, which is required for T4P assembly in Pseudomonas aeruginosa, localizes to the leading pole of twitching bacteria. Polar FimX localization requires both the presence of T4P assembly machine proteins and the assembly ATPase PilB. PilB itself loses its polar localization pattern when FimX is absent. We use two different approaches to confirm that FimX and PilB interact in vivo and in vitro, and further show that point mutant alleles of FimX that do not bind c-di-GMP also do not interact with PilB. Lastly, we demonstrate that FimX positively regulates T4P assembly and twitching motility by promoting the activity of the PilB ATPase, and not by stabilizing assembled pili or by preventing PilT-mediated retraction. Mutated alleles of FimX that no longer bind c-di-GMP do not allow rapid T4P assembly in these assays. We propose that by virtue of its high-affinity for c-di-GMP, FimX can promote T4P assembly when intracellular levels of this cyclic nucleotide are low. As P. aeruginosa PilB is not itself a high-affinity c-di-GMP receptor, unlike many other assembly ATPases, FimX may play a key role in coupling T4P mediated motility and adhesion to levels of this second messenger.


Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Fímbrias Bacterianas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Oxirredutases/metabolismo , Pseudomonas aeruginosa/metabolismo , Fatores de Virulência/metabolismo , Cromatografia em Gel , GMP Cíclico/análogos & derivados , GMP Cíclico/metabolismo , Processamento de Imagem Assistida por Computador , Microscopia Eletrônica de Transmissão , Reação em Cadeia da Polimerase , Ressonância de Plasmônio de Superfície , Virulência/fisiologia
16.
J Med Virol ; 91(3): 347-350, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30252936

RESUMO

Mumps, a vaccine-preventable disease, cause inflammation of salivary glands and may cause severe complications, such as encephalitis, meningitis, deafness, and orchitis/oophoritis. In India, mumps vaccine is not included in the universal immunization program and during 2009 to 2014, 72 outbreaks with greater than 1500 cases were reported. In August 2016, a suspected mumps outbreak was reported in Jaisalmer block, Rajasthan. We investigated to confirm the etiology, describe the epidemiology, and recommend prevention and control measures. We defined a case as swelling in the parotid region in a Jaisalmer block resident between 23 June 2016 and 10 September 2016. We searched for cases in health facilities and house-to-house in affected villages and hamlets. We tested blood samples of cases for mumps immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA). We found 162 cases (60% males) with a median age of 9.4 years (range: 7 month-38 years) and 65 (40%) were females. Symptoms included fever (70%) and bilateral swelling in neck (65%). None of them were vaccinated against mumps. Most (84%) cases were school-going children (3-16 years old). The overall attack rate was 2%. Village A, with two hamlets, had the highest attack rate (hamlet 1 = 13% and hamlet 2 = 12%). School A of village A, hamlet 1, which accommodated 200 children in two classrooms, had an attack rate of 55%. Of 18 blood samples from cases, 11 tested positive for mumps IgM ELISA. This was a confirmed mumps outbreak in Jaisalmer block that disproportionately affected school-going children. We recommended continued surveillance, 5-day absence from school, and vaccination.


Assuntos
Anticorpos Antivirais/sangue , Surtos de Doenças , Caxumba/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Imunoglobulina M/sangue , Incidência , Índia/epidemiologia , Lactente , Masculino , Caxumba/sangue , Vírus da Caxumba/imunologia , Vacinação/estatística & dados numéricos , Adulto Jovem
17.
J Neurooncol ; 141(2): 315-325, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30460633

RESUMO

PURPOSE: Peritumoural brain zone (PT) of glioblastoma (GBM) is the area where tumour recurrence is often observed. We aimed to identify differentially regulated genes between tumour core (TC) and PT to understand the underlying molecular characteristics of infiltrating tumour cells in PT. METHODS: 17 each histologically characterised TC and PT tissues of GBM along with eight control tissues were subjected to cDNA Microarray. PT tissues contained 25-30% infiltrating tumour cells. Data was analysed using R Bioconductor software. Shortlisted genes were validated using qRT-PCR. Expression of one selected candidate gene, PDZ Binding Kinase (PBK) was correlated with patient survival, tumour recurrence and functionally characterized in vitro using gene knock-down approach. RESULTS: Unsupervised hierarchical clustering showed that TC and PT have distinct gene expression profiles compared to controls. Further, comparing TC with PT, we observed a significant overlap in gene expression profile in both, despite PT having fewer infiltrating tumour cells. qRT-PCR for 13 selected genes validated the microarray data. Expression of PBK was higher in PT as compared to TC and recurrent when compared to newly diagnosed GBM tumours. PBK knock-down showed a significant reduction in cell proliferation, migration and invasion with increase in sensitivity to radiation and Temozolomide treatment. CONCLUSIONS: We show that several genes of TC are expressed even in PT contributing to the vulnerability of PT for tumour recurrence. PBK is identified as a novel gene up-regulated in PT of GBM with a strong role in conferring aggressiveness, including radio-chemoresistance, thus contributing to recurrence in GBM tumours.


Assuntos
Neoplasias Encefálicas/enzimologia , Regulação Neoplásica da Expressão Gênica , Glioblastoma/enzimologia , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Recidiva Local de Neoplasia/enzimologia , Transcriptoma , Biomarcadores Tumorais/genética , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/genética , Movimento Celular , Proliferação de Células , Células Cultivadas , Glioblastoma/diagnóstico , Glioblastoma/genética , Humanos , Invasividade Neoplásica , Recidiva Local de Neoplasia/diagnóstico , Recidiva Local de Neoplasia/genética , Regulação para Cima
19.
Inorg Chem ; 56(9): 5352-5360, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28394128

RESUMO

A tetrafacial water-soluble molecular barrel (1) was synthesized by coordination driven self-assembly of a symmetrical tetrapyridyl donor (L) with a cis-blocked 90° acceptor [cis-(en)Pd(NO3)2] (en = ethane-1,2-diamine). The open barrel structure of (1) was confirmed by single crystal X-ray diffraction. The presence of a hydrophobic cavity with large windows makes it an ideal candidate for encapsulation and carrying hydrophobic drug like curcumin in an aqueous medium. The barrel (1) encapsulates curcumin inside its molecular cavity and protects highly photosensitive curcumin from photodegradation. The photostability of encapsulated curcumin is due to the absorption of a high proportion of the incident photons by the aromatic walls of 1 with a high absorption cross-sectional area, which helps the walls to shield the guest even against sunlight/UV radiations. As compared to free curcumin in water, we noticed a significant increase in solubility as well as cellular uptake of curcumin upon encapsulation inside the water-soluble molecular barrel (1) in aqueous medium. Fluorescence imaging confirmed that curcumin was delivered into HeLa cancer cells by the aqueous barrel (1) with the retention of its potential anticancer activity. While free curcumin is inactive toward cancer cells in aqueous medium at room temperature due to negligible solubility, the determined IC50 value of ∼14 µM for curcumin in aqueous medium in the presence of the barrel (1) reflects the efficiency of the barrel as a potential curcumin carrier in aqueous medium without any other additives. Thus, two major challenges of increasing the bioavailability and stability of curcumin in aqueous medium even in the presence of UV light have been addressed by using a new supramolecular water-soluble barrel (1) as a drug carrier.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/química , Curcumina/farmacologia , Portadores de Fármacos/química , Paládio/química , Antineoplásicos/química , Antineoplásicos/efeitos da radiação , Complexos de Coordenação/síntese química , Complexos de Coordenação/efeitos da radiação , Complexos de Coordenação/toxicidade , Curcumina/química , Curcumina/efeitos da radiação , Portadores de Fármacos/síntese química , Portadores de Fármacos/efeitos da radiação , Portadores de Fármacos/toxicidade , Estabilidade de Medicamentos , Células HeLa , Humanos , Interações Hidrofóbicas e Hidrofílicas , Ligantes , Substâncias Macromoleculares/síntese química , Substâncias Macromoleculares/química , Substâncias Macromoleculares/efeitos da radiação , Substâncias Macromoleculares/toxicidade , Solubilidade , Raios Ultravioleta , Água/química
20.
Clin Exp Rheumatol ; 34(5): 901-909, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27382923

RESUMO

OBJECTIVES: To characterise associations of fatigue with other variables within a multidimensional health assessment questionnaire (MDHAQ) in routine care of patients with different rheumatic diagnoses. METHODS: All patients complete MDHAQ, which includes fatigue on a 0-10 visual analogue scale (VAS), and routine assessment of patient index data (RAPID3), a composite of function, pain, and patient global. Physicians complete a RheuMetric checklist which includes 4 VAS for overall global status (DOCGL), inflammation, damage, and distress. Median score for fatigue and other MDHAQ and RheuMetric scores were compared in 4 diagnosis groups: rheumatoid arthritis (RA), osteoarthritis (OA), systemic lupus erythematosus (SLE), and fibromyalgia (FM), using a Kruskall-Wallis test. Associations of fatigue with other variables were analysed using Spearman correlations and multivariate regressions. RESULTS: 612 patients were included: 173 RA, 199 with OA, 146 with SLE, and 94 with FM. Median fatigue was significantly higher in FM (7) than in RA (4), OA (5), and SLE (5). Fatigue was correlated significantly with all other MDHAQ scores, at higher levels in RA and SLE versus OA and FM. Fatigue was correlated significantly with DOCGL in RA, OA, SLE, but not FM. In multivariate analyses, fatigue scores were explained independently by higher pain and symptom number in RA; lower age and higher symptom number in OA; only higher pain in SLE; and none of the variables in FM. CONCLUSIONS: Fatigue is common in rheumatic diseases and strongly associated with higher pain and number of symptoms. The MDHAQ provides a useful tool to assess fatigue in clinical settings.


Assuntos
Fadiga/diagnóstico , Indicadores Básicos de Saúde , Nível de Saúde , Medidas de Resultados Relatados pelo Paciente , Doenças Reumáticas/diagnóstico , Adulto , Idoso , Lista de Checagem , Chicago/epidemiologia , Efeitos Psicossociais da Doença , Estudos Transversais , Avaliação da Deficiência , Fadiga/epidemiologia , Fadiga/fisiopatologia , Fadiga/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Medição da Dor , Valor Preditivo dos Testes , Prevalência , Prognóstico , Qualidade de Vida , Estudos Retrospectivos , Doenças Reumáticas/epidemiologia , Doenças Reumáticas/fisiopatologia , Doenças Reumáticas/psicologia , Índice de Gravidade de Doença , Inquéritos e Questionários
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