Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 116
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Curr Med Chem ; 2019 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-31584362

RESUMO

The next-generation immunotherapy can only be effective if researchers have an in-depth understanding of the function and regulation of Treg cells in antitumor immunity combined with the discovery of new immunity targets. This can enhance clinical efficacy of future and novel therapies and reduces any adverse reactions arising from the latter. This review discusses tumor treatment strategies using regulatory T (Treg) cell therapy in a tumor microenvironment (TME). It also discusses factors affecting TME instability as well as relevant treatments to prevent future immune disorders. It is prognosticated that PD-1 inhibitors are risky and their adverse effects should be taken into account when they are administered to treat acute myeloid leukemia (AML), lung adenocarcinoma, and prostate adenocarcinoma. In contrast, Treg molecular markers FoxP3 and CD25 analyzed here have stronger expression in almost all kinds of cancers compared with normal people. However, CD25 inhibitors are more effective compared to FoxP3 inhibitors, especially in combination with TGF-ß blockade, in predicting patient survival. According to the data obtained from the Cancer Genome Atlas, we then concentrate on AML immunotherapy and discuss different therapeutic strategies including anti-CD25/IL-2, anti-CTLA-4, anti-IDO, antityrosine kinase receptor, and anti-PI3K therapies and highlight the recent advances and clinical achievements in AML immunotherapy. In order to prognosticate the risk and adverse effects of key target inhibitors (namely against CTLA-4, FoxP3, CD25, and PD-1), we finally analyzed and compared the Cancer Genome Atlas derived from ten common cancers. This review shows that Treg cells are strongly increased in AML and the comparative review of key markers shows that Tregbased immunotherapy is not effective for all kinds of cancer. Therefore, blocking CD25(+)FoxP3(+) Treg cells is suggested in AML more than other kinds of cancer; meanwhile, Treg markers studied in other cancers have also great lessons for AML immunotherapy.

2.
Sci Total Environ ; 697: 134021, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31484095

RESUMO

Aerosol optical depth (AOD) from polar orbit satellites and meteorological factors have been widely used to estimate concentrations of surface particulate matter with an aerodynamic diameter <2.5 µm (PM2.5). However, estimations with high temporal resolution remain lacking because of the limitations of satellite observations. Here, we used AOD data with a temporal resolution of 1 h provided by a geostationary satellite called Himawari 8 to overcome this problem. We developed a stacking model, which contained three submodels of machine learning, namely, AdaBoost, XGBoost and random forest, stacked through a multiple linear regression model. Then, we estimated the hourly concentrations of PM2.5 in Central and Eastern China. The accuracy evaluation showed that the proposed stacking model performed better than the single models when applied to the test set, with an average coefficient of determination (R2) of 0.85 and a root-mean-square error (RMSE) of 17.3 µg/m3. Model precision reached its peak at 14:00 (local time), with an R2 (RMSE) of 0.92 (12.9 µg/m3). In addition, the spatial and temporal distributions of PM2.5 in Central and Eastern China were plotted in this study. The North China Plain was determined to be the most polluted area in China, with an annual mean PM2.5 concentration of 58 µg/m3 during daytime. Moreover, the pollution level of PM2.5 was the highest in winter, with an average concentration of 73 µg/m3.

3.
Res Microbiol ; 170(6-7): 243-255, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31325485

RESUMO

Bacteria usually produce, release and detect quorum sensing (QS)-based signal molecules, and successively orchestrate gene expression in respond to environmental changes. Pseudoalteromonas are typical marine bacteria, but knowledge on their QS systems is extremely fragmentary. In this study, genome sequencing of Pseudoalteromonas sp. R3 was performed. Accordingly, a QS working model including three sets of hierarchically organized QS systems was proposed in strain R3. Among them, the typical LuxI/R-type QS system using acyl-homoserine lactones (AHLs) as signal molecules was characterized. Sequence similarity analysis indicated luxI encoding AHLs synthase is novel. The luxR encoding AHLs receptor is directly adjacent to luxI downstream. Notably, mutagenesis demonstrated LuxI and LuxR affect each other at transcriptional level, and both control the AHLs formation. Interestingly, it was found that LuxI/R-type QS system positively involves resistance to streptomycin. Thin-layer chromatography analysis showed strain R3 can produce 3-OH-C6-HSL and C8-HSL, which was supported by heterologous expression of LuxI in Escherichia coli. Sequence alignment analysis indicated that the N-terminal region of LuxI is more conservative than the C-terminal region, revealing the importance of N-terminal region in AHLs synthesis. The obtained findings enrich our knowledge on LuxI/R-type QS system in Pseudoalteromonas and its regulation on adaptation to marine environments.

4.
Transl Oncol ; 12(10): 1323-1333, 2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-31352195

RESUMO

BACKGROUND: Gene expression can be posttranscriptionally regulated by a complex network of proteins. N1-methyladenosine (m1A) is a newly validated RNA modification. However, little is known about both its influence and biogenesis in tumor development. METHODS: This study analyzed TCGA data of patients with five kinds of gastrointestinal (GI) cancers. Using data from cBioPortal, molecular features of the nine known m1A-related enzymes in GI cancers were investigated. Using a variety of bioinformatics approach, the impact of m1A regulators on its downstream signaling pathway was studied. To further confirm this regulation, the effect of m1A writer ALKBH3 knockdown was studied using RNA-seq data from published database. RESULTS: Dysregulation and multiple types of genetic alteration of putative m1A-related enzymes in tumor samples were observed. The ErbB and mTOR pathways with ErbB2, mTOR, and AKT1S1 hub genes were identified as being regulated by m1A-related enzymes. The expression of both ErbB2 and AKT1S1 was decreased after m1A writer ALKBH3 knockdown. Furthermore, Gene Ontology analysis revealed that m1A downstream genes were associated with cell proliferation, and the results showed that m1A genes are reliably linked to mTOR. CONCLUSION: This study demonstrated for the first time the dysregulation of m1A regulators in GI cancer and its signaling pathways and will contribute to the understanding of RNA modification in cancer.

5.
Ultrasound Med Biol ; 45(9): 2525-2539, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31196746

RESUMO

Superharmonic imaging is an ultrasound contrast imaging technique that differentiates microbubble echoes from tissue through detection of higher-order bubble harmonics in a broad frequency range well above the excitation frequency. Application of superharmonic imaging in three dimensions allows specific visualization of the tissue microvasculature with high resolution and contrast, a technique referred to as acoustic angiography. Because of the need to transmit and receive across a bandwidth that spans up to the fifth harmonic of the fundamental and higher, this imaging approach requires imaging probes comprising dedicated transducers for transmit and receive. In this work, we report on a new dual-frequency probe including two 1.7-MHz rectangular transducers positioned one on each side of a 20-MHz 256-element array. Finite element modeling-based design, fabrication processes and assembly of the transducer are described, as is integration with a high-frequency ultrasound imaging platform. Dual-frequency single-plane-wave imaging was performed with a microbubble contrast agent in flow phantoms and compared with conventional high-frequency B-mode imaging, and resolution and contrast-to-tissue ratio were quantified. This work represents an intermediate but informative step toward the development of dual-frequency imaging probes based on array technology, specifically designed for clinical applications of acoustic angiography.

6.
Clin Cancer Res ; 25(18): 5525-5536, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31152021

RESUMO

PURPOSE: APOBEC3-UNG imbalance contributes to hepatitis B virus (HBV) inhibition and somatic mutations. We aimed to explore the associations between hepatocellular carcinoma (HCC) risk and genetic polymorphisms predisposing the imbalance.Experimental Design: Genetic polymorphisms at APOBEC3 promoter and UNG enhancer regions were genotyped in 5,621 participants using quantitative PCR. HBV mutations (nt.1600-nt.1945, nt.2848-nt.155) were determined by Sanger sequencing. Dual-luciferase reporter assay was applied to detect the transcriptional activity. Effects of APOBEC3B/UNG SNPs and expression levels on HCC prognosis were evaluated with a cohort of 400 patients with HCC and public databases, respectively. RESULTS: APOBEC3B rs2267401-G allele and UNG rs3890995-C allele significantly increased HCC risk. rs2267401-G allele was significantly associated with the generation of APOBEC-signature HBV mutation whose frequency consecutively increased from asymptomatic HBV carriers to patients with HCC. Multiplicative interaction of rs2267401-G allele with rs3890995-C allele increased HCC risk, with an adjusted OR (95% confidence interval) of 1.90 (1.34-2.81). rs2267401 T-to-G and rs3890995 T-to-C conferred increased activities of APOBEC3B promoter and UNG enhancer, respectively. IL6 significantly increased APOBEC3B promoter activity and inhibited UNG enhancer activity, and these effects were more evident in those carrying rs2267401-G and rs3890995-C, respectively. APOBEC3B rs2267401-GG genotype, higher APOBEC3B expression, and higher APOBEC3B/UNG expression ratio in HCCs indicated poor prognosis. APOBEC-signature somatic mutation predicts poor prognosis in HBV-free HCCs rather than in HBV-positive ones. CONCLUSIONS: Polymorphic genotypes predisposing the APOBEC3B-UNG imbalance in IL6-presenting microenvironment promote HCC development, possibly via promoting the generation of high-risk HBV mutations. This can be transformed into specific prophylaxis of HBV-caused HCC.

7.
Artigo em Inglês | MEDLINE | ID: mdl-30936102

RESUMO

Polymyxins are nonribosomal peptide antibiotics used as the last-resort drug for treatment of multidrug-resistant Gram-negative bacteria. However, strains that are resistant to polymyxins have emerged in many countries. Although several mechanisms for polymyxin resistance have been well described, there is little knowledge on the hydrolytic mechanism of polymyxin. Here, we identified a polymyxin-inactivating enzyme from Bacillus licheniformis strain DC-1 which was produced and secreted into the medium during entry into stationary phase. After purification, sequencing, and heterologous expression, we found that the alkaline protease Apr is responsible for inactivation of polymyxins. Analysis of inactivation products demonstrated that Apr cleaves polymyxin E at two peptide bonds: one is between the tripeptide side chain and the cyclic heptapeptide ring, the other between l-Thr and l-α-γ-diaminobutyric acid (l-Dab) within the cyclic heptapeptide ring. Apr is highly conserved among several genera of Gram-positive bacteria, including Bacillus and Paenibacillus It is noteworthy that two peptidases S8 from Gram-negative bacteria shared high levels of sequence identity with Apr. Our results indicate that polymyxin resistance may result from inactivation of antibiotics by hydrolysis.

8.
Spectrochim Acta A Mol Biomol Spectrosc ; 218: 243-247, 2019 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-31003049

RESUMO

Osteoarthritis (OA) is not only related to the degradation of articular cartilage, but also possibly to the changes of subchondral bone. The purpose of this study was to assess whether specific differences could be resolved from bone composition, as also contributed to OA. These differences were assessed by using Fourier transform infrared spectroscopy (FTIRS). The main parameters including mineral content, carbonate content, crystallinity, collagen cross-linking ratio (XLR) and acid phosphate content were represented with characteristic peak integration. It was found that mineral and carbonate content varied significantly with depths at different OA stages. Mineral content increased with depth in healthy samples, while carbonate content showed opposite trend. The mineral content reduced obviously with OA duration, which was different with carbonate decreasing only at early stage of OA. In addition, the content of acid phosphate, collagen maturity (XLR) and crystallinity slight varied with the OA aggravation. Therefore, the changes in subchondral bone were significantly associated with cartilage degeneration and OA, the associated parameters should be targeted for OA therapies.


Assuntos
Osso e Ossos/patologia , Osteoartrite/patologia , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Animais , Osso e Ossos/química , Carbonatos/análise , Colágeno/análise , Cães , Durapatita/análise , Minerais/análise , Fosfatos/análise
9.
Clin Chem ; 65(7): 905-915, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30996051

RESUMO

BACKGROUND: Reliable noninvasive biomarkers for hepatocellular carcinoma (HCC) diagnosis and prognosis are urgently needed. We explored the potential of not only microRNAs (miRNAs) but other types of noncoding RNAs (ncRNAs) as HCC biomarkers. METHODS: Peripheral blood samples were collected from 77 individuals; among them, 57 plasma cell-free RNA transcriptomes and 20 exosomal RNA transcriptomes were profiled. Significantly upregulated ncRNAs and published potential HCC biomarkers were validated with reverse transcription (RT)-qPCR in an independent validation cohort (60-150 samples). We particularly investigated the diagnosis and prognosis performance and biological function for 1 ncRNA biomarker, RN7SL1, and its S fragment. RESULTS: We identified certain circulating ncRNAs escaping from RNase degradation, possibly through binding with RNA-binding proteins: 899 ncRNAs were highly upregulated in HCC patients. Among them, 337 genes were fragmented long noncoding RNAs, 252 genes were small nucleolar RNAs, and 134 genes were piwi-interacting RNAs. Forty-eight candidates were selected and validated with RT-qPCR, of which, 16 ncRNAs were verified to be significantly upregulated in HCC, including RN7SL1, SNHG1, ZFAS1, and LINC01359. Particularly, the abundance of RN7SL1 S fragment discriminated HCC samples from negative controls (area under the curve, 0.87; 95% CI, 0.817-0.920). HCC patients with higher concentrations of RN7SL1 S fragment had lower survival rates. Furthermore, RN7SL1 S fragment alone promoted cancer cell proliferation and clonogenic growth. CONCLUSIONS: Our results show that various ncRNA species, not only miRNAs, identified in the small RNA sequencing of plasma are also able to serve as noninvasive biomarkers. Particularly, we identified a domain of srpRNA RN7SL1 with reliable clinical performance for HCC diagnosis and prognosis.

10.
Microb Drug Resist ; 25(3): 317-325, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30864883

RESUMO

Development of antibiotic resistance can be achieved either by mutation or by acquiring a resistance gene from foreign sources, with some resistance genes likely originating in microbial populations to counteract antibiotics present in natural ecosystems. In this study, we describe the first report of a strain of nonclinical multidrug-resistant Stenotrophomonas sp. strain G4 with high-level resistance to colistin and meropenem, phylogenetically distinct from well-studied multiple drug-resistant species of Stenotrophomonas maltophilia. As the high-level colistin resistance of this strain was of great concern, the genome of this strain was completely sequenced. Only one chromosome was identified, and no plasmids were found. Chromosomal gene variants and other potential genetic determinants conferring resistance to colistin and meropenem were comparatively analyzed, and results showed that strain G4 harbored two putative colistin resistance determinants (named mcr-5.3 and mcr-8.2) and four extended-spectrum ß-lactamase genes. In addition, 12 genes potentially encoding seven different types of efflux pumps were identified, which may have a major role in acquisition/transfer of colistin resistance. Our discovery of multiple antibiotic resistance determinants in this environmental strain extensively expands our understanding of the extent of dissemination of colistin and meropenem resistance.


Assuntos
Colistina/farmacologia , Farmacorresistência Bacteriana/genética , Meropeném/farmacologia , Esgotos/microbiologia , Stenotrophomonas maltophilia/efeitos dos fármacos , Stenotrophomonas maltophilia/isolamento & purificação , Antibacterianos/farmacologia , Stenotrophomonas maltophilia/genética , Água , Microbiologia da Água , beta-Lactamases/genética
11.
Molecules ; 24(3)2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30678237

RESUMO

The commonly believed mechanism of colistin against Gram-negative bacteria is to cause cell membrane lysis, whereas the mechanism of colistin against Gram-positive bacteria is extremely fragmented. In this study, we found that colistin treatment on Bacillus subtilis WB800, Paenibacillus polymyxa C12 and Paenibacillus polymyxa ATCC842 enhances not only the activities of α-ketoglutaric dehydrogenase and malate dehydrogenase in tricarboxylic acid (TCA) cycle, but also the relative expression levels of their encoding genes. Additionally, the oxaloacetate concentration also increases. Interestingly, the analysis of the relative expression of genes specific for respiratory chain showed that colistin treatment stimulates the respiratory chain in Gram-positive bacteria. Accordingly, the NAD⁺/NADH ratio increases and the oxidative level is then boosted up. As a result, the intensive oxidative damages are induced in Gram-positive bacteria and cells are killed. Notably, both rotenone and oligomycin, respectively, inhibiting NADH dehydrogenase and phosphorylation on respiratory chain can downgrade oxidative stress formation, thus alleviating the colistin-induced killing of Gram-positive cells. Besides, thiourea-based scavenging for reactive oxygen species also rescues the colistin-subjected cells. These data collectively demonstrate that colistin stimulates both TCA cycle and respiratory chain in Gram-positive bacteria, leading to the enhancement of NADH metabolism and resulting in the generation of oxidative damages in Gram-positive cells. Our studies provide a better understanding of antibacterial mechanism of colistin against Gram-positive bacteria, which is important for knowledge on bacterial resistance to colistin happening via the inhibition of respiratory chain and manipulation of its production.


Assuntos
Antibacterianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/metabolismo , Colistina/farmacologia , NAD/metabolismo , Paenibacillus polymyxa/efeitos dos fármacos , Paenibacillus polymyxa/metabolismo , Ciclo do Ácido Cítrico/efeitos dos fármacos , Transporte de Elétrons/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos
12.
Biomed Res Int ; 2018: 1934309, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30406130

RESUMO

Polymyxin E or colistin, produced by Paenibacillus polymyxa, is an important antibiotic against Gram-negative pathogens. The objective of this study is to evaluate the effect of starch in fermentation medium on colistin biosynthesis in P. polymyxa. The results indicated that replacement of glucose by starch stimulated colistin production and biosynthesis rate. Overall, the stimulation extent was starch concentration-dependent. As expected, addition of starch induced the expression of amyE encoding amylase and increased amylase activity in fermentation solution. Additionally, replacement of glucose by starch resulted in residue reducing sugar and pH of fermentation mixture low relative to glucose as the sole sugar source. At the molecular level, it was found that replacement of glucose by starch has enhanced the relative expression level of ccpA encoding catabolite control protein A. Therefore, the repression of starch utilization by glucose could be probably relieved. In addition, use of starch stimulated the expression of regulatory gene spo0A but repressed the expression of another regulatory gene abrB. As a result, the expression of genes directly involved in colistin biosynthesis and secretion increased, indicating that at the transcriptional level spo0A and abrB played opposite roles in regulating colistin biosynthesis in P. polymyxa. Taken together, our data demonstrated that starch instead of glucose can promote colistin production probably by affecting the expression of colistin biosynthesis-related genes, as well as reducing the repression of glucose to a secondary metabolic product.

13.
Cell Biol Toxicol ; 2018 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-30430365

RESUMO

Circulating tumor cells (CTCs) have important application prospects in the early diagnosis, treatment evaluation, and prognostic prediction of tumors. In this study, we enrolled a total of 65 patients with different stages and molecular subtypes of breast cancer and isolated and enriched for CTCs from peripheral blood using the ClearCell FX1 platform, which is based on a label-free spiral microfluidic method. The ClearCell platform can successfully isolate CTCs from peripheral blood with different detection rates in breast cancer patients. We also compared the difference between the ClearCell and CellSearch platforms for isolating CTCs. To further determine the genetic information of CTCs, we performed single-cell whole-exome sequencing (WES) in three CTCs isolated from one patient. The sequencing results indicated the presence of a few hundreds of single-nucleotide variants (SNVs) in each CTC, with only 16 SNVs being shared by all three CTCs. These shared SNVs may have a crucial impact on the development of breast cancer. Here, we report, for the first time, the complete process and results of performing single-cell WES on CTCs isolated by the ClearCell FX1 platform.

14.
Int J Mol Sci ; 19(11)2018 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-30453700

RESUMO

A bstract: Quorum sensing (QS) enables single-celled bacteria to communicate with chemical signals in order to synchronize group-level bacterial behavior. Pseudoalteromonas are marine bacteria found in versatile environments, of which QS regulation for their habitat adaptation is extremely fragmentary. To distinguish genes required for QS regulation in Pseudoalteromonas, comparative genomics was deployed to define the pan-genomics for twelve isolates and previously-sequenced genomes, of which acyl-homoserine lactone (AHL)-based QS traits were characterized. Additionally, transposon mutagenesis was used to identify the essential QS regulatory genes in the selected Pseudoalteromonas isolate. A remarkable feature showed that AHL-based colorization intensity of biosensors induced by Pseudoalteromonas most likely correlates with QS regulators genetic heterogeneity within the genus. This is supported by the relative expression levels of two of the main QS regulatory genes (luxO and rpoN) analyzed in representative Pseudoalteromonas isolates. Notably, comprehensive QS regulatory schema and the working model proposed in Pseudoalteromonas seem to phylogenetically include the network architectures derived from Escherichia coli, Pseudomonas, and Vibrio. Several associated genes were mapped by transposon mutagenesis. Among them, a right origin-binding protein-encoding gene (robp) was functionally identified as a positive QS regulatory gene. This gene lies on a genomic instable region and exists in the aforementioned bioinformatically recruited QS regulatory schema. The obtained data emphasize that the distinctly- and hierarchically-organized mechanisms probably target QS association in Pseudoalteromonas dynamic genomes, thus leading to bacterial ability to accommodate their adaption fitness and survival advantages.

15.
Sheng Wu Gong Cheng Xue Bao ; 34(8): 1288-1296, 2018 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-30152214

RESUMO

Beta-lactams are the most widely used antibiotics. One of the principle mechanisms for Gram-negative bacteria to resist ß-lactams is by producing ß-lactamases that degrade ß-lactams. This review highlights two regulatory mechanisms for inducing ß-lactamase in Gram-negative bacteria. In the ampR-ampC paradigm, the induction of ß-lactamase is intimately linked to peptidoglycan recycling. AmpR, a LysR-type transcriptional regulator, plays a central role in regulating expression of ß-lactamase. Recent studies found that two-component signal transduction pathway is activated by ß-lactams, which in turn induces the expression of ß-lactamase. Finally, we discussed the future research directions in ß-lactam resistance in Gram-negative bacteria.

16.
J Immunol Res ; 2018: 5081634, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30116753

RESUMO

γδ T cells, a subgroup of T cells based on the γδ TCR, when compared with conventional T cells (αß T cells), make up a very small proportion of T cells. However, its various subgroups are widely distributed in different parts of the human body and are attractive effectors for infectious disease immunity. γδ T cells are activated and expanded by nonpeptidic antigens (P-Ags), major histocompatibility complex (MHC) molecules, and lipids which are associated with different kinds of pathogen infections. Activation and proliferation of γδ T cells play a significant role in diverse infectious diseases induced by viruses, bacteria, and parasites and exert their potential effector function to effectively eliminate infection. It is well known that many types of infectious diseases are detrimental to human life and health and give rise to high incidence of illnesses and death rate all over the world. To date, there is no comprehensive understanding of the correlation between γδ T cells and infectious diseases. In this review, we will focus on the various subgroups of γδ T cells (mainly Vδ1 T cells and Vδ2 T cells) which can induce multiple immune responses or effective functions to fight against common pathogen infections, such as Mycobacterium tuberculosis, Listeria monocytogenes, influenza viruses, HIV, EBV, and HBV. Hopefully, the gamma-delta T cell study will provide a novel effective way to treat infectious diseases.


Assuntos
Infecções Bacterianas/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Subpopulações de Linfócitos T/imunologia , Viroses/imunologia , Animais , Humanos , Ativação Linfocitária/imunologia
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 205: 391-397, 2018 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-30041125

RESUMO

Fourier transform infrared spectroscopy imaging (FTIRSI) combined with spectral analysis and polarization approach was creatively used to investigate both structures of bilirubin (BR) precipitate and BR aggregate at liquid-liquid interface. It was found by spectral analysis that the internal hydrogen bonds of BR molecules all broke and the dihedral angles increased during the formation of BR aggregate at liquid-liquid interface. And the BR molecule might be of layer assembly along the long axis direction of CD half-group to form J-type aggregates, which could be parallel to the direction of the transition dipole moment of BR aggregate. The further study of polarized imaging/anisotropy revealed that the absorbance of 1570 and 1703 cm-1 bands of BR aggregate changed periodically at intervals of 90°, which were not shown in BR precipitate case, indicating that the CC of the corresponding lactam ring and the CO of the adjacent carboxyl groups formed ordered arrangement in BR aggregate. It also suggested that the two positions might be the active sites which J-type aggregates assembled on. The combined technique was firstly applied in interfacial aggregate research, which was helpful for further understanding and controlling the aggregation as well as structural transformation of BR molecules so as to decrease physiological hazard and facilitate the wide spread application in biomedicine.

18.
Cell Prolif ; 51(5): e12468, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29999557

RESUMO

OBJECTIVES: B7 family has been identified as co-stimulatory or co-inhibitory molecules on T-cell response and plays an important role in tumour mortality and malignancy. In this study, the expression pattern of B7 family in gastrointestinal (GI) cancer was examined. Its upstream regulating mechanism, downstream targets and association with clinical parameters were also studied. MATERIALS AND METHODS: The expression level of B7 members was analysed by FIREHOUSE. The gene mutation, DNA methylation, association with clinical parameters and downstream network of B7 members were analysed in cBioportal. The mutation frequency was analysed by Catalogue of Somatic Mutations in Cancer (COSMIC) analysis. The phylogenetic tree was constructed in MEGA7. The interaction protein domain analysis was performed by Pfam 31.0. RESULTS: Differential expression of B7 family molecules was detected in different kinds of GI cancer. High-frequency gene alteration was found in tumour samples. There was negative correlation of promoter methylation and mRNA expression of B7 family members in tumour samples, suggesting the epigenetic basis of B7 family gene deregulation in GI cancer. The overexpression of B7-H1 in pancreatic cancer, B7-H5 in oesophageal cancer and B7-H6 in liver cancer were significantly associated with worse overall survival. Finally, by network analysis, we identified some potential interacting proteins for B7-1/2 and B7-H1/DC. CONCLUSIONS: Overall, our study suggested that B7 member deregulation was strongly involved in GI cancer tumorigenesis.


Assuntos
Antígenos B7/genética , Neoplasias Gastrointestinais/genética , Metilação de DNA/genética , Humanos , Mutação/genética , Neoplasias Pancreáticas/genética , Filogenia , Regiões Promotoras Genéticas/genética
19.
FEMS Microbiol Lett ; 365(12)2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29788206

RESUMO

High molecular weight penicillin-binding proteins (PBPs) are responsible for the biosynthesis of peptidoglycan. In Escherichia coli, PBP1a and PBP1b form multienzyme peptidoglycan-synthesizing complexes with outer membrane lipoproteins LpoA and LpoB, respectively. The two complexes appear to be largely redundant, although their distinct physiological roles remain unclear. PBP1a/LpoA and PBP1b/LpoB also exist in Shewanella oneidensis strain MR-1, but effects of the two complexes on aerobic growth and ß-lactam resistance are quite different. In this study, the phenotypes of strains lacking a certain complex in S. oneidensis were compared. Deletion of PBP1a/LpoA caused aberrant cell morphology (including branches and bulges), enhanced sensitivity to various envelope stresses and outer membrane permeability. On the contrary, strains lacking PBP1b/LpoB displayed phenotypes similar to the wild type.

20.
Int J Syst Evol Microbiol ; 68(7): 2172-2177, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29767617

RESUMO

A Gram-strain-negative, coccoid bacterium, lacking bacteriochlorophyll, designated strain T1lg56T, was isolated from a sediment sample collected from Ximen island mangrove forest, Zhejiang province, China. Cells were halotolerant, and catalase- and oxidase-positive. Growth was observed at 18-42 °C (optimum, 35 °C), at pH 6.0-9.5 (optimum, pH 6.5) and in the presence of 0-15 % (w/v) NaCl (optimum, 2-5 %). The major cellular fatty acids were C18 : 1ω7c and C16 : 0. The polar lipid profile of strain T1lg56T consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylmonomethylethanolamine, two unidentified phospholipids and five unidentified lipids. Ubiquinone-10 was the predominant respiratory quinone. The assimilation of the substrates in the API 20NE kit was positive in strain T1lg56T. The DNA G+C content of strain T1lg56T was 67.2 mol%. 16S rRNA gene sequence analysis indicated that strain T1lg56T was a member of family Rhodobacteraceae and was closely related to Poseidonocella pacifica KMM 9010T, with 95.7 % similarity to the type strain. Phylogenetic analysis showed that strain T1lg56T formed a separate evolutionary branch, and was parallel to other related genera of Rhodobacteraceae. Its phylogenetic distinctiveness and distinguishing phenotypic characteristics supported that strain T1lg56T represents a novel genus of the family Rhodobacteraceae, for which the name Mangrovicoccus ximenensis gen. nov., sp. nov. is proposed. The type strain is T1lg56T (=CCTCC AB 2016238T=KCTC 52623T).


Assuntos
Sedimentos Geológicos/microbiologia , Filogenia , Rhizophoraceae , Rhodobacteraceae/classificação , Áreas Alagadas , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Rhodobacteraceae/genética , Rhodobacteraceae/isolamento & purificação , Análise de Sequência de DNA , Ubiquinona/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA