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1.
PLoS Pathog ; 18(2): e1010341, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35180278

RESUMO

The control of virulence gene regulator (CovR), also called caspsule synthesis regulator (CsrR), is critical to how the major human pathogen group A Streptococcus fine-tunes virulence factor production. CovR phosphorylation (CovR~P) levels are determined by its cognate sensor kinase CovS, and functional abrogating mutations in CovS can occur in invasive GAS isolates leading to hypervirulence. Presently, the mechanism of CovR-DNA binding specificity is unclear, and the impact of CovS inactivation on global CovR binding has not been assessed. Thus, we performed CovR chromatin immunoprecipitation sequencing (ChIP-seq) analysis in the emm1 strain MGAS2221 and its CovS kinase deficient derivative strain 2221-CovS-E281A. We identified that CovR bound in the promoter regions of nearly all virulence factor encoding genes in the CovR regulon. Additionally, direct CovR binding was observed for numerous genes encoding proteins involved in amino acid metabolism, but we found limited direct CovR binding to genes encoding other transcriptional regulators. The consensus sequence AATRANAAAARVABTAAA was present in the promoters of genes directly regulated by CovR, and mutations of highly conserved positions within this motif relieved CovR repression of the hasA and MGAS2221_0187 promoters. Analysis of strain 2221-CovS-E281A revealed that binding of CovR at repressed, but not activated, promoters is highly dependent on CovR~P state. CovR repressed virulence factor encoding genes could be grouped dependent on how CovR~P dependent variation in DNA binding correlated with gene transcript levels. Taken together, the data show that CovR repression of virulence factor encoding genes is primarily direct in nature, involves binding to a newly-identified DNA binding motif, and is relieved by CovS inactivation. These data provide new mechanistic insights into one of the most important bacterial virulence regulators and allow for subsequent focused investigations into how CovR-DNA interaction at directly controlled promoters impacts GAS pathogenesis.


Assuntos
Infecções Estreptocócicas , Fatores de Virulência , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Histidina Quinase/metabolismo , Humanos , Proteínas Repressoras/metabolismo , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/metabolismo , Virulência/genética , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
2.
Cogn Emot ; : 1-11, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38532640

RESUMO

Pride expressions draw attention to one's achievement, and therefore can enhance one's status. However, such attention has been linked to negative interpersonal consequences (i.e. envy). Fortunately, people have been found to regulate their pride expressions accordingly. Specifically, pride expressions are lower when the domain of the achievement is of high relevance to observers. We set out to replicate this effect in a non-Western sample. Additionally, we extended the current finding by investigating the moderating role of self-monitoring, an individual's ability and willingness to adjust their behaviours under different social contexts to cultivate status. This allows us to explore the previously assumed underlying status motive in regulating pride expressions. Data from two preregistered studies (N1 = 913; N2 = 1081) replicated the effect that pride expressions are inhibited when the achievement domain is relevant. A significant main effect of self-monitoring was found, such that high self-monitors express more pride than low self-monitors, consistent with the conceptualisation of self-monitoring as rooted within a status-enhancement motive. The assumed interaction effect between domain relevance and self-monitoring was not significant. Our findings suggest that the effect of domain relevance on pride expression is robust and status driven.

3.
Molecules ; 29(10)2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38792114

RESUMO

Flavonoids and stilbenoids, crucial secondary metabolites abundant in plants and fungi, display diverse biological and pharmaceutical activities, including potent antioxidant, anti-inflammatory, and antimicrobial effects. However, conventional production methods, such as chemical synthesis and plant extraction, face challenges in sustainability and yield. Hence, there is a notable shift towards biological production using microorganisms like Escherichia coli and yeast. Yet, the drawbacks of using E. coli and yeast as hosts for these compounds persist. For instance, yeast's complex glycosylation profile can lead to intricate protein production scenarios, including hyperglycosylation issues. Consequently, Corynebacterium glutamicum emerges as a promising alternative, given its adaptability and recent advances in metabolic engineering. Although extensively used in biotechnological applications, the potential production of flavonoid and stilbenoid in engineered C. glutamicum remains largely untapped compared to E. coli. This review explores the potential of metabolic engineering in C. glutamicum for biosynthesis, highlighting its versatility as a cell factory and assessing optimization strategies for these pathways. Additionally, various metabolic engineering methods, including genomic editing and biosensors, and cofactor regeneration are evaluated, with a focus on C. glutamicum. Through comprehensive discussion, the review offers insights into future perspectives in production, aiding researchers and industry professionals in the field.


Assuntos
Corynebacterium glutamicum , Flavonoides , Engenharia Metabólica , Estilbenos , Corynebacterium glutamicum/metabolismo , Corynebacterium glutamicum/genética , Engenharia Metabólica/métodos , Flavonoides/biossíntese , Flavonoides/metabolismo , Estilbenos/metabolismo
4.
J Bacteriol ; 205(6): e0011823, 2023 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-37289078

RESUMO

The control of virulence two-component gene regulatory system (CovRS) is critical to the pathogenesis of many medically important streptococci. In emm1 group A streptococci (GAS), CovR directly binds the promoters of numerous GAS virulence factor-encoding genes. Elimination of CovS phosphatase activity increases CovR phosphorylation (CovR~P) levels and abrogates GAS virulence. Given the emm type-specific diversity of CovRS function, in this study we used chromatin immunoprecipitation sequencing (ChIP-seq) to define global CovR DNA occupancy in the wild-type emm3 strain MGAS10870 (medium CovR~P) and its CovS phosphatase-negative derivative 10870-CovS-T284A (high CovR~P). In the wild-type emm3 strain, 89% of the previously identified emm1 CovR binding sites present in the emm3 genome were also enriched; additionally, we ascertained unique CovR binding, primarily to genes in mobile genetic elements and other sites of interstrain chromosomal differences. Elimination of CovS phosphatase activity specifically increased CovR occupancy at the promoters of a broad array of CovR repressed virulence factor-encoding genes, including those encoding the key GAS regulator Mga and M protein. However, a limited number of promoters had augmented enrichment at low CovR~P levels. Differential motif searches using sequences enriched at high versus low CovR~P levels revealed two distinct binding patterns. At high CovR~P, a pseudopalindromic AT-rich consensus sequence (WTWTTATAAWAAAAWNATDA) consistent with CovR binding as a dimer was determined. Conversely, sequences specifically enriched at low CovR~P contained isolated ATTARA motifs suggesting an interaction with a monomer. These data extend understanding of global CovR DNA occupancy beyond emm1 GAS and provide a mechanism for previous observations regarding hypovirulence induced by CovS phosphatase abrogation. IMPORTANCE Given its key role in pathogenesis of Gram-positive bacteria, CovR is one of the most important members of the OmpR/PhoB family of transcriptional regulators. Herein we extend recent GAS CovR global binding analyses done in emm1 to a non-emm1 strain, which is important considering the known inter-emm-type heterogeneity in GAS CovRS function. Our data provide mechanistic understanding for variation in CovRS function between emm types and the profound hypovirulence of CovS phosphatase-negative strains in addition to indicating differential targeting by phosphorylated and nonphosphorylated CovR isoforms at specific CovR binding sites. These findings advance knowledge regarding how a key bacterial virulence regulator impacts pathogenesis and add to the growing appreciation of the function of nonphosphorylated OmpR/PhoB family members.


Assuntos
Infecções Estreptocócicas , Fatores de Virulência , Humanos , Virulência , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Histidina Quinase/metabolismo , Streptococcus pyogenes/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Infecções Estreptocócicas/microbiologia , Regulação Bacteriana da Expressão Gênica
5.
Biochem Biophys Res Commun ; 653: 47-52, 2023 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-36857899

RESUMO

Redox regulation is a posttranslational modification based on the redox reaction of protein thiols. A small ubiquitous protein thioredoxin (Trx) plays a central role in redox regulation, but a unique redox-regulatory factor called NADPH-Trx reductase C (NTRC) is also found in plant chloroplasts and some cyanobacteria. Several important functions of NTRC have been suggested, but the mechanism for controlling NTRC activity remains undetermined. Cystathionine-ß-synthase X (CBSX) proteins have been previously shown to interact with NTRC physically. Based on these observations, this study biochemically investigated the functional interaction between CBSX proteins and NTRC from Arabidopsis thaliana in vitro. Consequently, we concluded that CBSX proteins act as negative regulators of NTRC in the presence of AMP.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Antioxidantes/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Cloroplastos/metabolismo , Cistationina/metabolismo , Cistationina beta-Sintase/metabolismo , Oxirredução , Tiorredoxina Dissulfeto Redutase/metabolismo , Tiorredoxinas/metabolismo
6.
Opt Lett ; 48(9): 2397-2400, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-37126282

RESUMO

Few-cycle, long-wavelength sources for generating isolated attosecond soft x ray pulses typically rely upon complex laser architectures. Here, we demonstrate a comparatively simple setup for generating sub-two-cycle pulses in the short-wave infrared based on multidimensional solitary states in an N2O-filled hollow-core fiber and a two-channel light-field synthesizer. Due to the temporal phase imprinted by the rotational nonlinearity of the molecular gas, the redshifted (from 1.03 to 1.36 µm central wavelength) supercontinuum pulses generated from a Yb-doped laser amplifier are compressed from 280 to 7 fs using only bulk materials for dispersion compensation.

7.
BMC Health Serv Res ; 23(1): 1126, 2023 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-37858102

RESUMO

BACKGROUND: Diabetic foot infection (DFI), including diabetic foot ulcer, is a serious complication of diabetes, particularly in the South Western Sydney (SWS) region where it is a leading cause of diabetes-related hospitalisations. Multidisciplinary team (MDT) involvement is effective at improving the health outcomes of DFI patients. This study investigated the impact of MDT (High Risk Foot Service, HRFS) on the length of stay and surgical outcomes of inpatients with DFI in a Sydney tertiary hospital. METHOD: A retrospective audit of electronic medical records of inpatient admissions for DFI at Campbelltown Hospital between January 2019 - December 2021, was performed. The main outcome of the study was MDT involvement, defined as having two or more specialities involved in the patient's treatment. The other measured variables included length of stay (defined as the total duration from admission to discharge), and surgical outcomes including debridement, minor amputation, and major amputation. RESULTS: Over the three years, 78 participants presented to the hospital for 89 unique DFI admissions. There were 24 admissions in 2019, 28 admissions in 2020, and 37 admissions in 2021, with MDT attendance showing a steady increase at 62.5%, 75.0% and 83.8% respectively. Patients with serious comorbidities such as chronic kidney disease were more likely to have MDT involvement (84.8% vs. 15.2%, P = 0.048). Imaging was more likely to be performed with MDT involvement (78.8% vs. 21.3%, p < 0.05). Comparing patients who received and did not receive MDT care, the mean HbA1c (%) (8.4 ± 2.0 vs. 8.2 ± 2.7, P = 0.701), median length of stay (LOS: 7.8, IQR 15.0 days vs. 4.8 IQR 7.9 days, P = 0.243) and rate of surgical outcomes (74.6% vs. 72.7%, P = 0.262) were similar. Patients who required major amputation had significantly longer LOS (24 days, IQR 21.5 vs. 5.2 days, IQR 13.0, P = 0.004) but similar HbA1c (P = 0.552) compared to those who had conservative intervention. CONCLUSION: Adopting an MDT approach was associated with more thorough investigation of DFI, with similar rates of surgical outcomes. Further research on the impacts of MDT on length of stay and surgical outcomes of DFI patients in other SWS hospitals is needed.


Assuntos
Diabetes Mellitus , Pé Diabético , Humanos , Pé Diabético/epidemiologia , Pé Diabético/cirurgia , Pacientes Internados , Estudos Retrospectivos , Hemoglobinas Glicadas , Centros de Atenção Terciária
8.
Int J Mol Sci ; 24(4)2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36835188

RESUMO

Derived from the natural language processing (NLP) algorithms, protein language models enable the encoding of protein sequences, which are widely diverse in length and amino acid composition, in fixed-size numerical vectors (embeddings). We surveyed representative embedding models such as Esm, Esm1b, ProtT5, and SeqVec, along with their derivatives (GoPredSim and PLAST), to conduct the following tasks in computational biology: embedding the Saccharomyces cerevisiae proteome, gene ontology (GO) annotation of the uncharacterized proteins of this organism, relating variants of human proteins to disease status, correlating mutants of beta-lactamase TEM-1 from Escherichia coli with experimentally measured antimicrobial resistance, and analyzing diverse fungal mating factors. We discuss the advances and shortcomings, differences, and concordance of the models. Of note, all of the models revealed that the uncharacterized proteins in yeast tend to be less than 200 amino acids long, contain fewer aspartates and glutamates, and are enriched for cysteine. Less than half of these proteins can be annotated with GO terms with high confidence. The distribution of the cosine similarity scores of benign and pathogenic mutations to the reference human proteins shows a statistically significant difference. The differences in embeddings of the reference TEM-1 and mutants have low to no correlation with minimal inhibitory concentrations (MIC).


Assuntos
Algoritmos , Proteínas , Humanos , Sequência de Aminoácidos , Aminoácidos , Biologia Computacional , Proteínas/química , Saccharomyces cerevisiae/genética , Proteômica
9.
Aging Male ; 25(1): 125-133, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35416126

RESUMO

OBJECTIVE: To explore the microbial etiology of urethritis in Vietnamese men and the association with patients' characteristics, especially their sexual behaviors. METHODS: This study was conducted on 349 men who presented with symptomatic urethritis and evidence of STIs (determined by multiplex PCR tests) at the Department of Andrology and Sexual Medicine-Hanoi Medical University Hospital. All information regarding medical history, sexual activities, and symptoms of urethritis was documented. RESULTS: C. trachomatis and N. gonorrhoea remained the two most common causative pathogens, followed by an unexpectedly high prevalence of Mycoplasma and Ureaplasma species. Coinfection was significant with a rate of 40.7%. Men who had sex with female sex workers (FSWs) were more likely to be positive with N. gonorrhoea but less likely to be positive with C. trachomatis and M. genitalium than those having sex with only one romantic partner. CONCLUSIONS: Our findings suggested the important role of other microorganisms, especially M. genitalium, in the etiology of urethritis in men besides the previously well-known causes of STIs. Since the coinfection rate is quite high, targeted treatment with clear microbial evidence should be considered rather than empiric antimicrobial therapy.


Assuntos
Coinfecção , Gonorreia , Infecções por Mycoplasma , Mycoplasma genitalium , Profissionais do Sexo , Infecções Sexualmente Transmissíveis , Uretrite , Chlamydia trachomatis , Coinfecção/complicações , Coinfecção/epidemiologia , Feminino , Gonorreia/complicações , Heterossexualidade , Humanos , Masculino , Infecções por Mycoplasma/complicações , Infecções por Mycoplasma/diagnóstico , Infecções por Mycoplasma/epidemiologia , Prevalência , Infecções Sexualmente Transmissíveis/complicações , Infecções Sexualmente Transmissíveis/epidemiologia , Uretrite/diagnóstico , Uretrite/epidemiologia , Uretrite/etiologia , Vietnã/epidemiologia
10.
Mol Ther ; 29(7): 2335-2349, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-33647456

RESUMO

Chimeric antigen receptor (CAR) T cell therapy has led to impressive clinical responses in patients with hematological malignancies; however, its effectiveness in patients with solid tumors has been limited. While CAR T cells for the treatment of advanced prostate and pancreas cancer, including those targeting prostate stem cell antigen (PSCA), are being clinically evaluated and are anticipated to show bioactivity, their safety and the impact of the immunosuppressive tumor microenvironment (TME) have not been faithfully explored preclinically. Using a novel human PSCA knockin (hPSCA-KI) immunocompetent mouse model, we evaluated the safety and therapeutic efficacy of PSCA-CAR T cells. We demonstrated that cyclophosphamide (Cy) pre-conditioning significantly modified the immunosuppressive TME and was required to uncover the efficacy of PSCA-CAR T cells in metastatic prostate and pancreas cancer models, with no observed toxicities in normal tissues with endogenous expression of PSCA. This combination dampened the immunosuppressive TME, generated pro-inflammatory myeloid and T cell signatures in tumors, and enhanced the recruitment of antigen-presenting cells, as well as endogenous and adoptively transferred T cells, resulting in long-term anti-tumor immunity.


Assuntos
Ciclofosfamida/farmacologia , Imunoterapia Adotiva/métodos , Proteínas de Neoplasias/antagonistas & inibidores , Neoplasias Pancreáticas/terapia , Neoplasias da Próstata/terapia , Microambiente Tumoral , Animais , Antígenos de Neoplasias/genética , Apoptose , Proliferação de Células , Proteínas Ligadas por GPI/antagonistas & inibidores , Proteínas Ligadas por GPI/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Agonistas Mieloablativos/farmacologia , Proteínas de Neoplasias/genética , Neoplasias Pancreáticas/imunologia , Neoplasias Pancreáticas/patologia , Neoplasias da Próstata/imunologia , Neoplasias da Próstata/patologia , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
11.
Opt Lett ; 46(10): 2437-2440, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33988603

RESUMO

Few-cycle sources with high average powers are required for applications to attosecond science. Raman-enhanced spectral broadening of Yb-doped laser amplifiers in molecular gases can yield few-cycle pulses, but thermal excitation of vibrational and rotational degrees of freedom may preclude high-power operation. Here we investigate changes in the spectral broadening associated with repetitive laser interactions in an ${{\rm{N}}_2}{\rm{O}}$-filled hollow-core fiber. By comparing experimental measurements of the spectrum associated with each laser pulse to simulations based on a density matrix model, we find that losses in a spectral bandwidth and transmission are largely dominated by thermal excitation of the gas.

12.
Br J Cancer ; 123(5): 762-771, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32546832

RESUMO

BACKGROUND: Subcutaneous mouse tumour models are widely used for the screening of novel antitumour treatments, although these models are poor surrogate models of human cancers. METHODS: We compared the antitumour efficacy of the combination of ionising radiation (IR) with two DNA damage response inhibitors, the PARP inhibitor olaparib and the ATR inhibitor AZD6738 (ceralasertib), in subcutaneous versus orthotopic cancer models. RESULTS: Olaparib delayed the growth of irradiated Lewis lung carcinoma (LL2) subcutaneous tumours, in agreement with previous reports in human cell lines. However, the olaparib plus IR combination showed a very narrow therapeutic window against LL2 lung orthotopic tumours, with nearly no additional antitumour effect compared with that of IR alone, and tolerability issues emerged at high doses. The addition of AZD6738 greatly enhanced the efficacy of the olaparib plus IR combination treatment against subcutaneous but not orthotopic LL2 tumours. Moreover, olaparib plus AZD6738 administration concomitant with IR even worsened the response to radiation of head and neck orthotopic tumours and induced mucositis. CONCLUSIONS: These major differences in the responses to treatments between subcutaneous and orthotopic models highlight the importance of using more pathologically relevant models, such as syngeneic orthotopic models, to determine the most appropriate therapeutic approaches for translation to the clinic.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Carcinoma Pulmonar de Lewis/radioterapia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Animais , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Quinase 1 do Ponto de Checagem/metabolismo , Quimiorradioterapia , Feminino , Indóis , Camundongos , Camundongos Endogâmicos C57BL , Morfolinas , Ftalazinas/administração & dosagem , Piperazinas/administração & dosagem , Inibidores de Poli(ADP-Ribose) Polimerases/administração & dosagem , Inibidores de Proteínas Quinases/administração & dosagem , Pirimidinas/administração & dosagem , Transdução de Sinais/efeitos dos fármacos , Sulfonamidas , Sulfóxidos/administração & dosagem
13.
Am J Physiol Gastrointest Liver Physiol ; 319(2): G175-G188, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32538140

RESUMO

Gastrokines (GKNs) are anti-inflammatory proteins secreted by gastric epithelial (surface mucous and pit) cells, with their aberrant loss of expression causally linked to premalignant inflammation and gastric cancer (GC). Transcriptional mechanisms accounting for GKN expression loss have not been elucidated. Using human clinical cohorts, mouse transgenics, bioinformatics, and transfection/reporter assays, we report a novel mechanism of GKN gene transcriptional regulation and its impairment in GC. GKN1/GKN2 loss is highly coordinated, with both genes showing parallel downregulation during human and mouse GC development, suggesting joint transcriptional control. In BAC transgenic studies, we defined a 152-kb genomic region surrounding the human GKN1/GKN2 genes sufficient to direct their tissue- and lineage-restricted expression. A screen of the 152-kb region for candidate regulatory elements identified a DNase I hypersensitive site (CR2) located 4 kb upstream of the GKN1 gene. CR2 showed overlapping enrichment of enhancer-related histone marks (H3K27Ac), a consensus binding site (GRE) for the glucocorticoid receptor (GR), strong GR occupancy in ChIP-seq data sets and, critically, exhibited dexamethasone-sensitive enhancer activity in reporter assays. Strikingly, GR showed progressive expression loss, paralleling that of GKN1/2, in human and mouse GC, suggesting desensitized glucocorticoid signaling as a mechanism underlying GKN loss. Finally, mouse adrenalectomy studies revealed a critical role for endogenous glucocorticoids in sustaining correct expression (and anti-inflammatory restraint) of GKNs in vivo. Together, these data link the coordinate expression of GKNs to a glucocorticoid-responsive and likely shared transcriptional enhancer mechanism, with its compromised activation contributing to dual GKN loss during GC progression.NEW & NOTEWORTHY Gastrokine 2 (GKN2) is an anti-inflammatory protein produced by the gastric epithelium. GKN2 expression is progressively lost during gastric cancer (GC), which is believed to play a casual role in GC development. Here, we use bacterial artificial chromosome transgenic studies to identify a glucocorticoid-responsive enhancer element that likely governs expression of GKN1/GKN2, which, via parallel expression loss of the anti-inflammatory glucocorticoid receptor, reveals a novel mechanism to explain the loss of GKN2 during GC pathogenesis.


Assuntos
Proteínas de Transporte/metabolismo , Glucocorticoides/farmacologia , Hormônios Peptídicos/metabolismo , Neoplasias Gástricas/metabolismo , Células A549 , Animais , Proteínas de Transporte/genética , Cromossomos Artificiais Bacterianos , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Camundongos Transgênicos , Família Multigênica , Hormônios Peptídicos/genética
14.
PLoS Pathog ; 14(10): e1007354, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30379939

RESUMO

The control of virulence regulator/sensor kinase (CovRS) two-component system is critical to the infectivity of group A streptococcus (GAS), and CovRS inactivating mutations are frequently observed in GAS strains causing severe human infections. CovS modulates the phosphorylation status and with it the regulatory effect of its cognate regulator CovR via its kinase and phosphatase activity. However, the contribution of each aspect of CovS function to GAS pathogenesis is unknown. We created isoallelic GAS strains that differ only by defined mutations which either abrogate CovR phosphorylation, CovS kinase or CovS phosphatase activity in order to test the contribution of CovR phosphorylation levels to GAS virulence, emergence of hypervirulent CovS-inactivated strains during infection, and GAS global gene expression. These sets of strains were created in both serotype M1 and M3 backgrounds, two prevalent GAS disease-causing serotypes, to ascertain whether our observations were serotype-specific. In both serotypes, GAS strains lacking CovS phosphatase activity (CovS-T284A) were profoundly impaired in their ability to cause skin infection or colonize the oropharynx in mice and to survive neutrophil killing in human blood. Further, response to the human cathelicidin LL-37 was abrogated. Hypervirulent GAS isolates harboring inactivating CovRS mutations were not recovered from mice infected with M1 strain M1-CovS-T284A and only sparsely recovered from mice infected with M3 strain M3-CovS-T284A late in the infection course. Consistent with our virulence data, transcriptome analyses revealed increased repression of a broad array of virulence genes in the CovS phosphatase deficient strains, including the genes encoding the key anti-phagocytic M protein and its positive regulator Mga, which are not typically part of the CovRS transcriptome. Taken together, these data establish a key role for CovS phosphatase activity in GAS pathogenesis and suggest that CovS phosphatase activity could be a promising therapeutic target in GAS without promoting emergence of hypervirulent CovS-inactivated strains.


Assuntos
Proteínas de Bactérias/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Nasofaringe/microbiologia , Monoéster Fosfórico Hidrolases/metabolismo , Pele/microbiologia , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/patogenicidade , Animais , Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Histidina Quinase , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Camundongos Pelados , Nasofaringe/enzimologia , Monoéster Fosfórico Hidrolases/genética , Fosforilação , Sorogrupo , Pele/enzimologia , Infecções Estreptocócicas/enzimologia , Streptococcus pyogenes/enzimologia , Virulência
15.
Med Mycol ; 57(5): 557-565, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30339200

RESUMO

Cryptococcosis causes approximately 180 000 deaths each year in patients with human immunodeficiency virus (HIV). Patients with other forms of immunosuppression are also at risk, and disease is increasingly recognized in apparently immunocompetent individuals. Cryptococcus neoformans var. grubii, responsible for the majority of cases, is distributed globally. We used the consensus ISHAM Multilocus sequence typing (MLST) scheme to define the population structure of clinical C. neoformans var. grubii isolates from Laos (n = 81), which we placed into the global context using published MLST data from other countries (total N = 1047), including a reanalysis of 136 Vietnamese isolates previously reported. We observed a phylogeographical relationship in which the Laotian population was similar to its neighbor Thailand, being dominated (83%) by Sequence Types (ST) 4 and 6. This phylogeographical structure changed moving eastwards, with Vietnam's population consisting of an admixture of isolates dominated by the ST4/ST6 (35%) and ST5 (48%) lineages. The ST5 lineage is the predominant ST reported from China and East Asia, where it accounts for >90% of isolates. Analysis of genetic distance (Fst) between different populations of C. neoformans var. grubii supports this intermediate structure of the Vietnamese population. The pathogen and host diversity reported from Vietnam provide the strongest epidemiological evidence of the association between ST5 and HIV-uninfected patients. Regional anthropological genetic distances suggest diversity in the C. neoformans var. grubii population across Southeast Asia is driven by ecological rather than human host factors. Where the ST5 lineage is present, disease in HIV-uninfected patients is to be expected.

16.
Drug Dev Ind Pharm ; 45(3): 514-519, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30575412

RESUMO

The objective of this study was to achieve an optimal formulation of hydrophilic-hydrophobic conjugates for nano-sized solid dispersions (SDs) with enhanced dissolution of multiple drugs in different gastrointestinal (GI) tract environments. A new conjugate powder with an optimized process was used to fabricate SDs that contained three poorly water-soluble drugs that were also poorly soluble in different dissolution media. The self-assembled nanoparticle formation, drug crystallinity and SD molecular interactions were investigated by measuring the particle size during dissolution testing and physicochemical property analysis (powder X-ray diffraction and Fourier transform infrared spectroscopy). Drug release studies indicated that SD containing conjugated powder significantly improved the dissolution rates of these poorly water-soluble drugs in the GI tract. In addition, particle size analysis showed nano-sized particles in the dissolution media in the early stage with a tendency to reduce smaller particles over time. Physicochemical characterizations demonstrated almost amorphous drug states and hydrogen bonding interactions between the drugs and conjugates in the SD. This study optimized a promising material for SD, and the material was shown to have a promising performance under various pH medium conditions with poorly water-soluble drugs.


Assuntos
Nanopartículas/química , Preparações Farmacêuticas/química , Água/química , Varredura Diferencial de Calorimetria/métodos , Química Farmacêutica/métodos , Portadores de Fármacos/química , Liberação Controlada de Fármacos/efeitos dos fármacos , Ligação de Hidrogênio/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Difração de Raios X/métodos
17.
Glob Chang Biol ; 24(3): 1069-1084, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-28922515

RESUMO

Climate warming is affecting the structure and function of river ecosystems, including their role in transforming and transporting carbon (C), nitrogen (N), and phosphorus (P). Predicting how river ecosystems respond to warming has been hindered by a dearth of information about how otherwise well-studied physiological responses to temperature scale from organismal to ecosystem levels. We conducted an ecosystem-level temperature manipulation to quantify how coupling of stream ecosystem metabolism and nutrient uptake responded to a realistic warming scenario. A ~3.3°C increase in mean water temperature altered coupling of C, N, and P fluxes in ways inconsistent with single-species laboratory experiments. Net primary production tripled during the year of experimental warming, while whole-stream N and P uptake rates did not change, resulting in 289% and 281% increases in autotrophic dissolved inorganic N and P use efficiency (UE), respectively. Increased ecosystem production was a product of unexpectedly large increases in mass-specific net primary production and autotroph biomass, supported by (i) combined increases in resource availability (via N mineralization and N2 fixation) and (ii) elevated resource use efficiency, the latter associated with changes in community structure. These large changes in C and nutrient cycling could not have been predicted from the physiological effects of temperature alone. Our experiment provides clear ecosystem-level evidence that warming can shift the balance between C and nutrient cycling in rivers, demonstrating that warming will alter the important role of in-stream processes in C, N, and P transformations. Moreover, our results reveal a key role for nutrient supply and use efficiency in mediating responses of primary producers to climate warming.


Assuntos
Mudança Climática , Ecossistema , Temperatura Alta , Nitrogênio/metabolismo , Fósforo/metabolismo , Rios , Processos Autotróficos , Biomassa , Carbono , Ciclo do Carbono , Fixação de Nitrogênio , Temperatura
18.
Pituitary ; 21(3): 274-282, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29380110

RESUMO

PURPOSE: Hypophysitis develops in up to 19% of melanoma patients treated with ipilimumab, a cytotoxic T-lymphocyte antigen-4 antibody. Early detection may avert life-threatening hypopituitarism. We aimed to assess the incidence of ipilimumab-induced hypophysitis (IH) at a quaternary melanoma referral centre, and to determine whether cortisol or thyroid stimulating hormone (TSH) monitoring could predict IH onset. METHODS: We performed a retrospective cohort study of ipilimumab-treated patients at a quaternary melanoma referral centre in Australia. The inclusion criteria were patients with metastatic or unresectable melanoma treated with ipilimumab monotherapy, and cortisol and TSH measurements prior to ≥ 2 infusions. The main outcomes were IH incidence and TSH and cortisol patterns in patients who did and did not develop IH. RESULTS: Of 78 ipilimumab-treated patients, 46 met the study criteria and 9/46 (20%) developed IH at a median duration of 13.0 weeks (range 7.7-18.1) following ipilimumab initiation. All patients whose TSH fell ≥ 80% compared to baseline developed IH, and, in 5/9 patients with IH, TSH fell prior to cortisol fall and IH diagnosis. Pre-cycle-4 TSH was significantly lower in those who developed IH (0.31 vs. 1.73 mIU/L, P = 0.006). TSH fall was detected at a median time of 9.2 (range 7.7-16.4) weeks after commencing ipilimumab, and a median of 3.6 (range of - 1.4 to 9.7) weeks before IH diagnosis. There was no difference in TSH between the groups before cycles 1-3 or in cortisol before cycles 1-4. CONCLUSIONS: TSH fall ≥ 80% may be an early marker of IH. Serial TSH measurement during ipilimumab therapy may be an inexpensive tool to expedite IH diagnosis.


Assuntos
Hipofisite/sangue , Ipilimumab/uso terapêutico , Tireotropina/sangue , Feminino , Humanos , Hidrocortisona/sangue , Hipopituitarismo/sangue , Masculino , Estudos Retrospectivos
19.
Proc Natl Acad Sci U S A ; 110(22): 9072-7, 2013 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-23674683

RESUMO

Dengue is the most prevalent arboviral disease of humans. The host and virus variables associated with dengue virus (DENV) transmission from symptomatic dengue cases (n = 208) to Aedes aegypti mosquitoes during 407 independent exposure events was defined. The 50% mosquito infectious dose for each of DENV-1-4 ranged from 6.29 to 7.52 log10 RNA copies/mL of plasma. Increasing day of illness, declining viremia, and rising antibody titers were independently associated with reduced risk of DENV transmission. High early DENV plasma viremia levels in patients were a marker of the duration of human infectiousness, and blood meals containing high concentrations of DENV were positively associated with the prevalence of infectious mosquitoes 14 d after blood feeding. Ambulatory dengue cases had lower viremia levels compared with hospitalized dengue cases but nonetheless at levels predicted to be infectious to mosquitoes. These data define serotype-specific viremia levels that vaccines or drugs must inhibit to prevent DENV transmission.


Assuntos
Aedes/virologia , Vírus da Dengue/genética , Dengue/epidemiologia , Dengue/transmissão , Dengue/virologia , Insetos Vetores/virologia , Animais , Sequência de Bases , Estudos de Coortes , Vírus da Dengue/classificação , Ensaio de Imunoadsorção Enzimática , Interações Hospedeiro-Patógeno , Humanos , Funções Verossimilhança , Modelos Genéticos , Dados de Sequência Molecular , Filogenia , Prevalência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Sorotipagem , Vietnã/epidemiologia , Viremia/epidemiologia
20.
J Infect Dis ; 212(8): 1182-90, 2015 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-25784733

RESUMO

Aedes albopictus is secondary to Aedes aegypti as a vector of dengue viruses (DENVs) in settings of endemicity, but it plays an important role in areas of dengue emergence. This study compared the susceptibility of these 2 species to DENV infection by performing 232 direct blood-feeding experiments on 118 viremic patients with dengue in Vietnam. Field-derived A. albopictus acquired DENV infections as readily as A. aegypti after blood feeding. Once infected, A. albopictus permitted higher concentrations of DENV RNA to accumulate in abdominal tissues, compared with A. aegypti. However, the odds of A. albopictus having infectious saliva were lower than the odds observed for A. aegypti (odds ratio, 0.70; 95% confidence interval, .52-.93). These results quantitate the susceptibility of A. albopictus to DENV infection and will assist parameterization of models for predicting disease risk in settings where A. albopictus is present.


Assuntos
Aedes/virologia , Vírus da Dengue/fisiologia , Dengue/transmissão , Insetos Vetores/virologia , Adulto , Animais , Dengue/virologia , Suscetibilidade a Doenças , Feminino , Humanos , Masculino , Saúde Pública , Vietnã , Viremia/virologia , Adulto Jovem
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