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1.
J Hazard Mater ; 471: 134255, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38669934

RESUMO

In recent years, large quantities of pharmaceuticals and personal care products (PPCPs) have been discharged into sewers, while the mechanisms of PPCPs enrichment in sewer sediments have rarely been revealed. In this study, three PPCPs (tetracycline, sulfamethoxazole, and triclocarban) were added consecutively over a 90-day experimental period to reveal the mechanisms of PPCPs enrichment and the transmission of resistance genes in sewer sediments. The results showed that tetracycline (TC) and triclocarban (TCC) have higher adsorption concentration in sediments compared to sulfamethoxazole (SMX). The absolute abundance of Tets and suls genes increased in sediments under PPCPs pressure. The increase in secretion of extracellular polymeric substances (EPS) and the loosening of the structure exposed a large number of hydrophobic functional groups, which promoted the adsorption of PPCPs. The absolute abundance of antibiotic resistance genes (ARGs), EPS and the content of PPCPs in sediments exhibited significant correlations. The enrichment of PPCPs in sediments was attributed to the accumulation of EPS, which led to the proliferation of ARGs. These findings contributed to further understanding of the fate of PPCPs in sewer sediments and opened a new perspective for consideration of controlling the proliferation of resistance genes.


Assuntos
Cosméticos , Esgotos , Sulfametoxazol , Tetraciclina , Poluentes Químicos da Água , Sulfametoxazol/análise , Adsorção , Tetraciclina/análise , Poluentes Químicos da Água/análise , Sedimentos Geológicos/química , Carbanilidas/análise , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos , Antibacterianos , Preparações Farmacêuticas/análise , Matriz Extracelular de Substâncias Poliméricas
2.
Drug Des Devel Ther ; 18: 859-870, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38524880

RESUMO

Background: Early recognition of castration-resistant state is of significance for timely adjustment of treatment regimens and improvement of prognosis. Purpose: This study aims to screen new aptamers CRda8 and CRda21 which recognize castration resistant prostate cancer (CRPC) cells with high affinity and specificity by SELEX technology. Methods: The enrichment of specific aptamer candidates was monitored by flow cytometric analysis. The affinity and specificity of aptamer candidates were evaluated by flow cytometry and immunofluorescence assay. MR imaging of CRda21-conjugated polyethylene glycol (PEG)-Fe3O4 nanoparticles to CRPC was further explored in vivo. Results: Both aptamers showed high specificity to target cells with dissociation constants in the nanomolar range, and did not recognize other tested cells. The staining of clinical tissue sections with fluorescent dye labeled aptamers showed that sections from CRPC exhibited stronger fluorescence while sections from benign prostatic hyperplasia and androgen dependent prostate cancer did not exhibit notable fluorescence. In vivo MRI demonstrated that CRda21-conjugated PEG-Fe3O4 had good affinity to CRPC and produced strong T2WI signal intensity reduction distinguished from peritumoral tissue. Conclusion: The high affinity and specificity of CRda8 and CRda21 make the aptamer hold potential for early recognition of castration-resistant state and diagnosis of CRPC at the cellular level.


Assuntos
Aptâmeros de Nucleotídeos , Hiperplasia Prostática , Neoplasias de Próstata Resistentes à Castração , Masculino , Humanos , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Linhagem Celular Tumoral , Corantes Fluorescentes
3.
J Med Microbiol ; 73(3)2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38440953

RESUMO

Introduction. The increasing prevalence and growing resistance of fungi present a significant peril to public health. There are only four classes of antifungal medicines available today, and few candidates are in clinical trials.Hypothesis/Gap Statement. Rapid and sensitive diagnostic techniques are lacking for most fungal pathogens, and those that do exist are expensive or hard to obtain.Aim. This study aimed to evaluate the feasibility of a novel automated antifungal susceptibility testing system, Fungus AST, in comparison to the broth microdilution method (BMD) recommended by the Clinical and Laboratory Standards Institute (CLSI).Methodology. A total of 101 clinical Candida spp. isolates were collected from the Zengcheng Branch of Nanfang Hospital and subjected to antifungal susceptibility testing. Antifungal susceptibility was assessed using the Fungus AST method and the BMD.Results. In this study, we introduce a novel automated antifungal susceptibility testing system, Fungus AST, which detects the turbidity and/or colour intensity of microdilution wells using a four-wavelength detection technology in real time and is designed to match the growth characteristics of strains over time. Based on our analysis, all reportable ranges of Fungus AST were suitable for clinical fungal isolates in PR China. Within ±twofold dilutions, reproducibility was 100 %. Considering the BMD as a referenced method, ten antifungal agents (anidulafungin, caspofungin, micafungin, fluconazole, voriconazole, posaconazole, itraconazole, amphotericin B, 5-flucytosine and nystatin) showed an essential agreement of >95 %. The category agreement of five antifungal agents (anidulafungin, caspofungin, micafungin, fluconazole and voriconazole) was excellent at >90 %. One Candida albicans isolate and voriconazole showed a major error (ME) (1.7 %), and no other ME or very ME agents were found.Conclusion. Given the above, it can be argued that the utilization of Fungus AST is a discretionary automated approach. More improvements are needed in Fungus AST compared to the BMD system for a wider range of clinical isolates, including different types of fungi.


Assuntos
Antifúngicos , Colorimetria , Antifúngicos/farmacologia , Voriconazol , Fluconazol , Anidulafungina , Caspofungina , Micafungina , Reprodutibilidade dos Testes , Nefelometria e Turbidimetria , Algoritmos
4.
Int Immunopharmacol ; 112: 109196, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36084539

RESUMO

OBJECTIVE: The levels of serum M. pneumoniae typing antibodies in children with community-acquired pneumonia (CAP) were detected by chemiluminescent immunoassay (CLIA) to explore the clinical role of M. pneumoniae typing antibody (MP-IgM, MP-IgG) in M. pneumoniae pneumonia. METHODS: A total of 387 Child patients with CAP diagnosed at the Pediatric outpatient department of Zengcheng Branch, Nanfang Hospital, Southern Medical University, were enrolled between January 2020 to December 2021 and divided into M. pneumoniae pneumonia (MPP) group (n = 210) and non-M. pneumoniae pneumonia (NMPP) group (n = 177). Firstly, Clinical data, full blood count (WBC, NEU%, LYM%, MONO%, EOS%, BASO%, RBC, HGB, PLT) and biochemical tests (AST, LDH, ɑ-HBDH, CK, CKMB, CRP, PCT, IL-6) as well as laboratory diagnostic tests (MP-IgM, MP-IgG) were compared between the two groups. Secondly, we assessed the correlation between the average level of M. pneumoniae typing antibody detected by CLIA and the titer of anti-M. pneumoniae antibody (MP-Ab) tested by passive agglutination (PA) method. Thirdly, receiver operating characteristic (ROC) curve for the MP-IgM and MP-IgG was examined to evaluate the value of diagnosing M. pneumoniae pneumonia. Finally, we follow-up 120 cases of MPP group and analysis medication results. RESULTS: (1) Mean age, runny nose, expectoration, LYM%, NEU%, HGB, AST, MP-IgM and MP-IgG were statistically significant in the MPP group and NMPP group (all P < 0.05). (2) Correlation analysis showed that MP-IgM average level was linearly associated with MP-Ab titer (R2 = 0.84) and MP-IgG average level was exponentially correlated with MP-Ab titer under 1:640 (R2 = 0.96). (3) The ROC curve of MP-IgM and MP-IgG were significantly different (both P < 0.001). A serum MP-IgM level above 1 S/CO and MP-IgG level above 14.15 AU/mL were significant predictors for M. pneumoniae pneumonia: area under the curve (AUC) of 0.810, 0.815; standard error (SE) of 0.021, 0.022; 95 % confidence interval (CI) of 0.768-0.852, 0.773-0.858; the diagnostic sensitivity of 74.3 %, 62.1 %; and specificity of 72.9 %, 87.0 %; respectively. (4) Of the 120 children with M. pneumoniae pneumonia followed up, 79 (65.8 %) cases took azithromycin and 68 (86.1 %) cases were recovered. CONCLUSIONS: A series of our studies shown that, CLIA, speedy and automated clinical examination method, has higher specificity and sensitivity for the quantitative detection of MP-IgM and MP-IgG, playing an important role of early diagnosis as well as prompt intervention to reduces macrolide-resistant strains and sequelae of children with M. pneumoniae pneumonia.


Assuntos
Infecções Comunitárias Adquiridas , Pneumonia por Mycoplasma , Criança , Humanos , Mycoplasma pneumoniae , Azitromicina , Interleucina-6 , Anticorpos Antibacterianos , Pneumonia por Mycoplasma/diagnóstico , Imunoglobulina M , Infecções Comunitárias Adquiridas/diagnóstico , Imunoglobulina G , Imunoensaio
5.
Cell Prolif ; 55(5): e13241, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35504605

RESUMO

OBJECTIVES: Hepatocellular carcinoma (HCC) still presents a high incidence of malignant tumours with poor prognosis. There is an urgent need for new therapeutic agents with high specificity, low toxicity and favourable solubility for the clinical treatment of HCC. MATERIALS AND METHODS: The bioactivity of human umbilical cord serum was investigated by proteomics biotechnology and a primitive peptide with certain biological activity was identified. The antitumour effect of RR-171 was detected by cell viability assay in vitro, and determined by subcutaneous xenograft models assay and miniPDX assay in vivo. Pull-down experiments were conducted to identify the potential targeting proteins of RR-171. Immunofluorescence assay and tubulin polymerization assay were conducted to explore the relationship between RR-171 and α-tubulin. Fluorescence imaging in xenograft models was used to explore the biodistribution of RR-171 in vivo. A phosphospecific protein microarray was performed to uncover the underlying signalling pathway by which RR-171 induces tumour cell death. RESULTS: The results indicated that RR-171 could be effective in the treatment of HCC in vivo and in vitro. RR-171 could aggregate significantly in solid tumours and had no obvious systemic toxicity in vivo. RR-171 could interact with α-tubulin and activate the NF-Kappa B pathway in HCC cells. CONCLUSIONS: Taken together, RR-171 exhibited significant antitumour activity against HCC in vivo and in vitro and could potentially be used in the clinical application of HCC.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Animais , Apoptose , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Neoplasias Hepáticas/patologia , Camundongos , Camundongos Nus , NF-kappa B/metabolismo , Peptídeos/farmacologia , Peptídeos/uso terapêutico , Distribuição Tecidual , Tubulina (Proteína)/metabolismo , Cordão Umbilical/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Front Cardiovasc Med ; 9: 860059, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35557513

RESUMO

Introduction: Patients with incomplete revascularization (ICR) tend to develop refractory angina despite optimal medical therapy. The Compound Danshen Dripping Pills (CDDP) is a widely used antianginal drug in China and is shown to significantly alleviate myocardial ischemia. Previous studies showed dose-efficacy tendency when increasing doses of CDDP. This study aims to investigate the efficacy and safety of intensive doses of CDDP in patients with refractory angina with ICR. Methods and Analysis: The INCODER study is a multicenter, double-blind, randomized controlled, superiority trial. We plan to recruit 250 patients aged 18-85 years with a diagnosis of refractory angina with ICR. Patients will be randomized (1:1) to intensive treatment group (CDDP 20 pills three times per day) or standard treatment group (10 pills CDDP and 10 pills placebo three times per day). Patients will have a 6-week medication period and be followed up every 2 weeks. The primary endpoint is the change of total exercise time from baseline to week 6 as assessed by cardiopulmonary exercise testing (CPET). Secondary endpoints include changes in the frequency of angina, Canadian Cardiovascular Society angina class, nitroglycerin use, Seattle Angina Questionnaire scores, peak oxygen uptake (VO2 peak) and other parameters as measured by CPET, and the levels of plasma C-reactive protein, homocysteine, and N-terminal pro-B-type natriuretic peptide. Safety events related to CDDP use will be monitored. Ethics and Dissemination: The research had been approved by the Clinical research and laboratory animal ethics committee of the First Affiliated Hospital, Sun Yat-sen University ([2019]65). The results will be reported through peer-reviewed journals, seminars, and conference presentations. Trial Registration Number: www.chictr.org.cn (ChiCTR2000032384). Registered on 27 April 2020.

7.
Drug Des Devel Ther ; 15: 3985-3996, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34584404

RESUMO

BACKGROUND: The sensitive and specific detection of pathogenic cells is important in tumor diagnosis at an early stage. Aptamers are short single-stranded oligonucleotides evolved from systematic evolution of ligands by exponential enrichment (SELEX). It has been proved that aptamers can interact with cognate target molecules with high affinity and specificity and have great potential in the development of medical imaging at molecular level. PURPOSE: To select epithelial cell adhesion molecule (EpCAM) specific aptamers targeting prostate cancer and further to conjugate aptamers with GoldMag nanoparticles (a typical iron oxide core/gold shell structure) to construct magnetic molecular probes for medical imaging. METHODS: EpCAM-specific aptamers were selected by Cell-SELEX. The enrichment of specific aptamer candidates was monitored by flow cytometric analysis. Aptamers were further conjugated with GoldMag nanoparticles to construct magnetic molecular probes. The affinity and specificity of aptamer candidates and aptamer-conjugated GoldMag nanoparticles were evaluated. The MR imaging of aptamer-conjugated GoldMag nanoparticles to prostate cancer was further explored in vitro and in vivo. RESULTS: After 12 rounds of selection, aptamer candidates Eppc6 and Eppc14 could specifically target three types of prostate cancer cells, revealing a high affinity of Eppc6 and Eppc14. Moreover, aptamer-conjugated GoldMag nanoparticles not only exhibited good affinity to different prostate cancer cells but also produced strong T2WI signal intensity reduction distinguished from peritumoral tissue in MRI, indicating that the molecular probes possess both the affinity properties of EpCAM-specific aptamer and the superparamagnetic features of iron oxide. CONCLUSION: Our study indicates that aptamer Eppc6 and Eppc14 can recognize prostate cancer cells and tissues. The aptamer-conjugated GoldMag nanoparticles constructed in the study can be used as a molecular imaging agent for detection of PCa in MRI.


Assuntos
Aptâmeros de Nucleotídeos/administração & dosagem , Molécula de Adesão da Célula Epitelial/metabolismo , Nanopartículas Magnéticas de Óxido de Ferro , Neoplasias da Próstata/diagnóstico por imagem , Animais , Linhagem Celular Tumoral , Ouro/química , Células HEK293 , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Técnica de Seleção de Aptâmeros , Ensaios Antitumorais Modelo de Xenoenxerto
8.
Chin Med J (Engl) ; 134(7): 792-799, 2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33661141

RESUMO

BACKGROUND: Norepinephrine infusion decreases hypotension after spinal anesthesia during cesarean section. This study aimed to compare the efficacy of norepinephrine infusion and ephedrine bolus against post-spinal hypotension in parturients. METHODS: In this double-blinded, randomized controlled clinical trial, parturients scheduled for elective cesarean section were randomly allocated to receive norepinephrine infusion (0.05 µg·kg-1·min-1) just before spinal anesthesia continuing for 30 min or ephedrine bolus (0.15 mg/kg) just before spinal anesthesia. A rescue bolus (5 µg norepinephrine for the norepinephrine group, and 5 mg ephedrine for the ephedrine group) was administered whenever hypotension occurred. Our primary outcome was the incidence of hypotension within 30 min of spinal anesthesia administration. Secondary outcomes included maternal and neonatal outcomes 30 min after spinal block, and neonatal cerebral oxygenation 10 min after birth. RESULTS: In total, 190 patients were enrolled; of these patients, 177 were included in the final analysis. Fewer patients suffered hypotension in the norepinephrine group than in the ephedrine group (29.5% vs. 44.9%, odds ratio [OR]: 0.51, 95% confidence interval [CI]: 0.28-0.95, P = 0.034). Moreover, the tachycardia frequency was lower in the norepinephrine group than in the ephedrine group (OR: 0.22, 95% CI: 0.11-0.44, P < 0.001), and patients suffered less nausea and vomiting (OR: 0.28, 95% CI: 0.11-0.70, P = 0.004). There was no difference in Apgar scores and umbilical arterial blood gas analysis between the two groups. However, neonatal cerebral regional saturations were significantly higher after birth in the norepinephrine group than in the ephedrine group (mean difference: 2.0%, 95% CI: 0.55%-3.45%, P = 0.008). CONCLUSION: In patients undergoing elective cesarean section with spinal anesthesia, norepinephrine infusion compared to ephedrine bolus resulted in less hypotension and tachycardia, and exhibited potential neonatal benefits. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02542748; https://clinicaltrials.gov/ct2/show/record/NCT02542748.


Assuntos
Raquianestesia , Hipotensão , Raquianestesia/efeitos adversos , Cesárea/efeitos adversos , Método Duplo-Cego , Feminino , Humanos , Hipotensão/tratamento farmacológico , Hipotensão/prevenção & controle , Recém-Nascido , Fenilefrina , Gravidez , Ensaios Clínicos Controlados Aleatórios como Assunto , Vasoconstritores/uso terapêutico
9.
J Med Virol ; 93(6): 3374-3382, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-32841419

RESUMO

Yellow fever is an acute infectious disease that is common in Africa and South America and causes thousands of deaths annually. However, there are very few studies on yellow fever virus (YFV) antigen detection kits. As a detection target, the nonstructural protein 1 (NS1) has been successfully used in the early diagnosis of dengue virus (a member of the Flaviviridae family) infection. In this study, we used monoclonal antibody technology to prepare anti-YFV NS1 monoclonal antibodies (MAbs) and identified their immunological properties. Next, we used two mouse MAbs that can recognize different epitopes of YFV NS1 as capture and detection antibodies to establish a YFV NS1 antigen-capture enzyme-linked immunosorbent assay (ELISA). The antigen-capture ELISA displayed exclusive specificity to YFV without cross-reaction with other related members of the flavivirus family, including the dengue virus, West Nile virus, Japanese encephalitis virus. Additionally, the detection sensitivity towards the YFV culture supernatant was 103 TCID50/mL and the detection positivity rate was 95% compared with reverse transcription-polymerase chain reaction. In conclusion, this newly developed NS1 antigen-capture ELISA with high sensitivity and specificity could be used as an efficient method for the early diagnosis of YFV infection in animals or humans.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Proteínas não Estruturais Virais/imunologia , Vírus da Febre Amarela/imunologia , Animais , Anticorpos Antivirais/isolamento & purificação , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática/métodos , Ensaio de Imunoadsorção Enzimática/normas , Epitopos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Sensibilidade e Especificidade , Organismos Livres de Patógenos Específicos , Febre Amarela/diagnóstico , Febre Amarela/imunologia , Vírus da Febre Amarela/química
10.
Fertil Steril ; 114(5): 1108-1115, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33036792

RESUMO

OBJECTIVE: To present the first live birth after uterine transplantation (UTx) in the People's Republic of China. DESIGN: Case study. SETTING: University hospital. PATIENT(S): A 22-year-old woman with Mayer-Rokitansky-Kuster-Hauser syndrome and previous surgery for vaginal reconstruction and UTx. INTERVENTION(S): Endometrial preparation, frozen embryo transfer, pregnancy follow-up, and cesarean section. MAIN OUTCOME MEASURE(S): Results of in vitro fertilization, frozen embryo transfer, ultrasound measurements during pregnancy, rejection diagnosis and treatment, delivery, live birth, and histology of uterus. RESULTS(S): Frozen embryo (cleavage stage) transfer started 1.5 years after UTx. The first embryo transfer (n = 2) resulted in a biochemical pregnancy. The second, third, and fourth embryo transfer (n = 2, 2, 3) did not result in pregnancy. The fifth embryo transfer (n = 3) resulted in pregnancy with two gestational sacs, but with spontaneous disappearance of one in early pregnancy. During early pregnancy three episodes of vaginal bleedings occurred (gestational weeks 6 + 2, 13 + 1, and 16 + 3), with a spontaneously resorbing subchorionic hematoma diagnosed at the last bleeding episode. Bleeding episodes were treated with corticosteroids and tacrolimus. During pregnancy, blood flow velocity waveforms and fetal growth parameters were normal. A subacute cesarean section was performed at gestational week 33 + 6 due to uterine contraction pattern suggesting imminent labor. A healthy boy (2,000 g) with Apgar scores of 10, 10, 10 was delivered. The uterus was kept for a possible second pregnancy. CONCLUSION(S): The first live birth after UTx in the People's Republic of China is reported and this occurred after a robotic-assisted laparoscopic uterus retrieval from the mother.


Assuntos
Transtornos 46, XX do Desenvolvimento Sexual/cirurgia , Anormalidades Congênitas/cirurgia , Transferência Embrionária/métodos , Fertilização in vitro/métodos , Nascido Vivo , Ductos Paramesonéfricos/anormalidades , Transplante de Órgãos/métodos , Útero/transplante , Transtornos 46, XX do Desenvolvimento Sexual/diagnóstico por imagem , China , Anormalidades Congênitas/diagnóstico por imagem , Feminino , Humanos , Imunossupressores/uso terapêutico , Recém-Nascido , Masculino , Ductos Paramesonéfricos/diagnóstico por imagem , Ductos Paramesonéfricos/cirurgia , Gravidez , Útero/diagnóstico por imagem , Adulto Jovem
11.
J Agric Food Chem ; 66(42): 11055-11063, 2018 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-30351049

RESUMO

Two glycoside hydrolases encoded by the mannan utilization gene cluster of alkaliphilic Bacillus sp. N16-5 were studied. The recombinant Gal27A (rGal27A) hydrolyzed both galactomannans and oligo-galactomannans to release galactose, while the recombinant Man113A (rMan113A) showed poor activity toward galactomannans, but it hydrolyzed manno-oligosaccharides to release mannose and mannobiose. rGal27A showed synergistic interactions with rMan113A and recombinant ß-mannanase ManA (rManA), which is also from Bacillus sp. N16-5, in galactomannan degradation. The synergy degree of rGal27A and rManA on hydrolysis of locust bean gum and guar gum was 1.13 and 2.21, respectively, and that of rGal27A and rMan113A reached 2.00 and 2.68. The main products of galactomannan hydrolyzed by rGal27A and rManA simultaneously were galactose, mannose, mannobiose, and mannotriose, while those of galactomannan hydrolyzed by rGal27A and rMan113A were galactose and mannose. The yields of mannose, mannobiose, and mannotriose dramatically increased compared with the hydrolysis in the presence of rManA or rMan113A alone.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/metabolismo , Mananas/metabolismo , beta-Manosidase/metabolismo , Bacillus/química , Bacillus/genética , Bacillus/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Biocatálise , Galactanos/química , Galactose/análogos & derivados , Mananas/química , Família Multigênica , Gomas Vegetais/química , beta-Manosidase/química , beta-Manosidase/genética
12.
FEMS Microbiol Lett ; 365(4)2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29360976

RESUMO

Bacillus sp. N16-5 is an alkaliphile with a great ability to utilize mannan. Its mannan utilization gene cluster has been identified in a previous study. The ManR protein encoded by the cluster was predicted to be a LacI family regulator, and the transcription level of the mannan utilization gene cluster was upregulated after the manR gene was deleted, indicating that ManR is the repressor of this cluster. The transcription of the related genes was downregulated when manH, encoding the extracellular substrate-binding domain of the manno-oligosaccharide transporter, was deleted. Furthermore, isothermal titration calorimetry revealed that mannotetraose and mannopentose are ligands of ManR. These results all corroborate the hypothesis that the mannan utilization gene cluster is repressed by the transcription regulator ManR, and that the repression is removed when it binds to manno-oligosaccharides, which are generated by mannan degradation and transported into the cell by a specific transporter.


Assuntos
Álcalis/metabolismo , Bacillus/metabolismo , Regulação Bacteriana da Expressão Gênica , Mananas/metabolismo , Transcrição Gênica , Bacillus/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Mananas/química , Família Multigênica
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