Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 19 de 19
Filter
1.
Cancer Lett ; 593: 216963, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38768682

ABSTRACT

Neoadjuvant tyrosine kinase inhibitor (TKI) therapy is an important treatment option for advanced renal cell carcinoma (RCC). Many RCC patients may fail to respond or be resistant to TKI therapy. We aimed to explore the key mechanisms of neoadjuvant therapy résistance. We obtained tumor samples from matched pre-treatment biopsy and post-treatment surgical samples and performed single-cell RNA sequencing. Sunitinib-resistant ccRCC cell lines were established. Ferroptosis was detected by ferrous ion and lipid peroxidation levels. Tumor growth and resistance to Sunitinib was validated in vitro and vivo. Immunohistochemistry was used to validate the levels key genes and lipid peroxidation. Multi-center cohorts were included, including TCGA, ICGC, Checkmate-025 and IMmotion151 clinical trial. Survival analysis was performed to identify the associated clinical and genomic variables. Intratumoral heterogeneity was first described in the whole neoadjuvant management. The signature of endothelial cells was correlated with drug sensitivity and progression-free survival. Ferroptosis was shown to be the key biological program in malignant cell resistance. We observed tissue lipid peroxidation was negatively correlated with IL6 and tumor response. TKI-resistant cell line was established. SLC7A11 knockdown promoted cell growth and lipid peroxidation, increased the ferroptosis level, and suppressed the growth of tumor xenografts significantly (P < 0.01). IL6 could reverse the ferroptosis and malignant behavior caused by SLC7A11 (-) via JAK2/STAT3 pathway, which was rescued by the ferroptosis inducer Erastin. Our data indicate that ferroptosis is a novel strategy for advanced RCC treatment, which activated by IL6, providing a new idea for resistance to TKIs.


Subject(s)
Amino Acid Transport System y+ , Carcinoma, Renal Cell , Drug Resistance, Neoplasm , Ferroptosis , Kidney Neoplasms , Neoadjuvant Therapy , Sunitinib , Carcinoma, Renal Cell/drug therapy , Carcinoma, Renal Cell/pathology , Carcinoma, Renal Cell/genetics , Carcinoma, Renal Cell/metabolism , Ferroptosis/drug effects , Ferroptosis/genetics , Humans , Kidney Neoplasms/pathology , Kidney Neoplasms/drug therapy , Kidney Neoplasms/genetics , Kidney Neoplasms/metabolism , Neoadjuvant Therapy/methods , Sunitinib/pharmacology , Animals , Cell Line, Tumor , Mice , Amino Acid Transport System y+/genetics , Amino Acid Transport System y+/metabolism , Xenograft Model Antitumor Assays , Protein Kinase Inhibitors/pharmacology , Lipid Peroxidation/drug effects , STAT3 Transcription Factor/metabolism , STAT3 Transcription Factor/genetics , Female , Male , Molecular Targeted Therapy , Interleukin-6/metabolism , Interleukin-6/genetics , Disease Progression
2.
Acta Cir Bras ; 39: e391424, 2024.
Article in English | MEDLINE | ID: mdl-38511762

ABSTRACT

PURPOSE: XinJiaCongRongTuSiZiWan (XJCRTSZW) is a traditional Chinese medicine compound for invigorating the kidney, nourishing blood, and promoting blood circulation. This study aimed to explore the effect of XJCRTSZW on triptolide (TP)-induced oxidative stress injury. METHODS: Adult female Sprague-Dawley rats and human ovarian granulosa cell lines were treated with TP and XJCRTSZW. Hematoxylin and eosin staining, enzyme-linked immunosorbent assay, flow cytometry, CCK-8, JC-1 staining, transmission electron microscopy, reverse transcription-quantitative polymerase chain reaction, and Western blotting were performed in this study. RESULTS: XJCRTSZW treatment observably ameliorated the TP-induced pathological symptoms. Furthermore, XJCRTSZW treatment observably enhanced the TP-induced reduction of estradiol, anti-Mullerian hormone, progesterone, superoxide dismutase, ATP content, mitochondrial membrane potential, p62, and Hsp60 mRNA, and protein levels in vivo and in vitro (p < 0.05). However, TP-induced elevation of follicle stimulating hormone and luteinizing hormone concentrations, malondialdehyde levels, reactive oxygen species levels, apoptosis rate, mitophagy, and the mRNA and protein expressions of LC3-II/LC3-I, PTEN-induced kinase 1 (PINK1), and Parkin were decreased (p < 0.05). In addition, XJCRTSZW treatment markedly increased cell viability in vitro (p < 0.05). CONCLUSIONS: XJCRTSZW protects TP-induced rats from oxidative stress injury via the mitophagy-mediated PINK1/Parkin pathway.


Subject(s)
Diterpenes , Mitochondria , Mitophagy , Phenanthrenes , Adult , Rats , Female , Humans , Animals , Rats, Sprague-Dawley , Oxidative Stress , Ubiquitin-Protein Ligases , Signal Transduction , Protein Kinases/metabolism , Protein Kinases/pharmacology , RNA, Messenger/metabolism , Epoxy Compounds
3.
Acta cir. bras ; 39: e391424, 2024. graf
Article in English | LILACS-Express | LILACS, VETINDEX | ID: biblio-1556674

ABSTRACT

ABSTRACT Purpose: XinJiaCongRongTuSiZiWan (XJCRTSZW) is a traditional Chinese medicine compound for invigorating the kidney, nourishing blood, and promoting blood circulation. This study aimed to explore the effect of XJCRTSZW on triptolide (TP)-induced oxidative stress injury. Methods: Adult female Sprague-Dawley rats and human ovarian granulosa cell lines were treated with TP and XJCRTSZW. Hematoxylin and eosin staining, enzyme-linked immunosorbent assay, flow cytometry, CCK-8, JC-1 staining, transmission electron microscopy, reverse transcription-quantitative polymerase chain reaction, and Western blotting were performed in this study. Results: XJCRTSZW treatment observably ameliorated the TP-induced pathological symptoms. Furthermore, XJCRTSZW treatment observably enhanced the TP-induced reduction of estradiol, anti-Mullerian hormone, progesterone, superoxide dismutase, ATP content, mitochondrial membrane potential, p62, and Hsp60 mRNA, and protein levels in vivo and in vitro (p < 0.05). However, TP-induced elevation of follicle stimulating hormone and luteinizing hormone concentrations, malondialdehyde levels, reactive oxygen species levels, apoptosis rate, mitophagy, and the mRNA and protein expressions of LC3-II/LC3-I, PTEN-induced kinase 1 (PINK1), and Parkin were decreased (p < 0.05). In addition, XJCRTSZW treatment markedly increased cell viability in vitro (p < 0.05). Conclusions: XJCRTSZW protects TP-induced rats from oxidative stress injury via the mitophagy-mediated PINK1/Parkin pathway.

4.
Materials (Basel) ; 15(21)2022 Nov 05.
Article in English | MEDLINE | ID: mdl-36363402

ABSTRACT

Selective laser melting manufacture of patient specific Ti implants is serving as a promising approach for bone tissue engineering. The success of implantation is governed by effective osseointegration, which depends on the surface properties of implants. To improve the bioactivity and osteogenesis, the universal surface treatment for SLM-Ti implants is to remove the primitive roughness and then reengineer new roughness by various methods. In this study, the micro-sized partially melted Ti particles on the SLM-Ti surface were preserved for assembling mesoporous bioactive glass nanospheres to obtain a unique micro/nano- topography through combination of SLM manufacture and sol-gel processes. The results of simulated body fluid immersion test showed that bioactive ions (Ca, Si) can be continuously and stably released from the MBG nanospheres. The osseointegration properties of SLM-Ti samples, examined using pre-osteoblast cells, showed enhanced adhesion and osteogenic differentiation compared with commercial pure titanium commonly used as orthopedic implants. Overall, the developed approach of construction of the dual micro/nano topography generated on the SLM-Ti native surface could be critical to enhance musculoskeletal implant performance.

5.
Mol Med ; 28(1): 107, 2022 09 06.
Article in English | MEDLINE | ID: mdl-36068527

ABSTRACT

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease that affects newborns, particularly preterm infants, and is associated with high morbidity and mortality. No effective therapeutic strategies to decrease the incidence and severity of NEC have been developed to date. Stem cell therapy has been explored and even applied in various diseases, including gastrointestinal disorders. Animal studies on stem cell therapy have made great progress, and the anti-inflammatory, anti-apoptotic, and intestinal barrier enhancing effects of stem cells may be protective against NEC clinically. In this review, we discuss the therapeutic mechanisms through which stem cells may function in the treatment of NEC.


Subject(s)
Enterocolitis, Necrotizing , Animals , Cell- and Tissue-Based Therapy , Enterocolitis, Necrotizing/therapy , Humans , Infant, Newborn , Infant, Premature , Intestines , Stem Cells
6.
Front Surg ; 9: 901615, 2022.
Article in English | MEDLINE | ID: mdl-36090320

ABSTRACT

Background: Nodal status is a vital prognostic factor for ampullary adenocarcinoma. This study was designed to evaluate the clinical significance of the positive nodes in this disease. Methods: Data from 110 patients who underwent curative pancreatoduodenectomy for ampullary adenocarcinoma between January 2007 and December 2018 were retrospectively collected and analyzed. Results: The median number of lymph nodes per patient was 32 (20-46). Metastatic lymph nodes were found in 84 (76.4%) patients. In patients with positive nodules, the most commonly involved nodes were the #13 (80.1%) and #17 (78.6%) nodes, followed by #12 (69.0%) and #8 nodes (57.1%). Patients with 3-4 positive nodes among #13, #17, #12, and #8 had lower survival rates than those with 0 or 1-2 nodes. Conclusion: Ampullary adenocarcinoma commonly spreads to #13, #17, #12, and #8 lymph nodes. These nodes affected the patients' survival rates dramatically.

7.
World J Surg Oncol ; 20(1): 210, 2022 Jun 21.
Article in English | MEDLINE | ID: mdl-35729607

ABSTRACT

BACKGROUND: The risk of HCC is documented to be age-related. The outcomes of young HCC patients on postoperative prognosis are not well understood. The study aims to compare the characteristic differences between adolescent and young (AYA) and non-AYA HCC patients. METHODS: We performed a retrospective analysis of the clinical and pathological findings and the survival of 243 HCC patients who underwent operations between 2007 and 2018. RESULTS: The AYA group had a higher AFP level and a higher prevalence of family history of HCC or other cancers than the non-AYA group (P < 0.01 and P < 0.05). AYA patients had more unfavorable pathological characteristics including bigger lesion size, microvascular invasion, portal vein invasion, and hepatic capsule invasion. They also had a more unfavorable Edmondson grade and less tumor capsule formation (P < 0.01). Age was an independent predictor of survival in HCC patients. AYA patients had poorer disease-free and overall survival than non-AYA patients did (P < 0.01). Patients under 30 years old had an even poorer disease-free survival than those aged 30-40 (P = 0.047). CONCLUSIONS: AYA patients exhibited a higher recurrence rate and disease-related death rate with more unfavorable pathological characteristics. Enhanced follow-up for young HCC patients should be applied.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Adolescent , Adult , Carcinoma, Hepatocellular/pathology , Hepatectomy , Humans , Liver Neoplasms/pathology , Neoplasm Recurrence, Local/pathology , Prognosis , Retrospective Studies
8.
Front Surg ; 9: 833373, 2022.
Article in English | MEDLINE | ID: mdl-35372475

ABSTRACT

Objective: Tumor recurrence remains the main dilemma after surgical treatment of ampulla of Vater carcinoma. This study was designed to identify the prognostic factors and evaluate the recurrence patterns of ampulla of Vater cancer. Methods: A total of 286 patients who underwent surgical resection of ampulla of Vater cancer in two medical centers from January 2000 to October 2016 were collected. Data on clinicopathologic factors, survival rate, and recurrence patterns were retrospectively analyzed. Results: A total of 158 patients (55.2%) survived without evidence of recurrence (non-recurrence), whereas 65 (22.7%) and 63 patients (22.1%) suffered from recurrence of the disease within 12 months (early recurrence) and after 12 months (late recurrence), respectively. Early-recurrence patients exhibited a more advanced disease (advanced tumor stage, lymph node involvement, pancreas invasion, and late TNM stage) than late-recurrence patients. The first or primary location of cancer recurrence in 33 patients (25.8%) was locoregional. Metastasis developed in the liver in 30 patients (23.4%), peritoneum in 13 patients (10.2%), lungs in 10 patients (7.8%), and para-aortic or superior mesenteric artery lymph node in 10 patients (7.8%). Multiple metastases were observed in 26 patients (20.3%). Conclusion: The most common patterns of postoperative recurrence are locoregional and recurrent liver metastasis. The recurrence patterns with the worst prognosis are peritoneal and multiple metastases.

9.
Materials (Basel) ; 14(8)2021 Apr 07.
Article in English | MEDLINE | ID: mdl-33916954

ABSTRACT

China is developing an ADS (Accelerator-Driven System) research device named the China initiative accelerator-driven system (CiADS). When performing a safety analysis of this new proposed design, the core behavior during the steam generator tube rupture (SGTR) accident has to be investigated. The purpose of our research in this paper is to investigate the impact from different heating conditions and inlet steam contents on steam bubble and coolant temperature distributions in ADS fuel assemblies during a postulated SGTR accident by performing necessary computational fluid dynamics (CFD) simulations. In this research, the open source CFD calculation software OpenFOAM, together with the two-phase VOF (Volume of Fluid) model were used to simulate the steam bubble behavior in heavy liquid metal flow. The model was validated with experimental results published in the open literature. Based on our simulation results, it can be noticed that steam bubbles will accumulate at the periphery region of fuel assemblies, and the maximum temperature in fuel assembly will not overwhelm its working limit during the postulated SGTR accident when the steam content at assembly inlet is less than 15%.

10.
J Cell Mol Med ; 25(9): 4248-4259, 2021 05.
Article in English | MEDLINE | ID: mdl-33749070

ABSTRACT

Cytoplasmic lncRNAs have been found to directly interact with target mRNAs and regulate their stability. In this study, we aimed to study the molecular mechanism underlying the function of m6 A as a central regulator in chemoresistance and CML proliferation. In this study, we established three mice groups (control group, ADR-R group and ADR-R + shLINC00470 group). We detected PTEN mRNA expression in the presence of LINC00470 in the mice models, as well as in the KCL22 and K562 cells. LINC00470 was significantly enriched for PTEN mRNA to exhibit a negative regulatory relationship between LINC00470 and PTEN mRNA. However, the alteration of LINC00470 had no effect on the luciferase activity of PTEN promoter, while the half-life of PTEN mRNA was affected. It was further validated that LINC00470 down-regulated PTEN expression by positively regulating the m6A modification of PTEN mRNA via RNA methyltransferase METTL3. Moreover, the relative expression of LC3II, Beclin-1, ATG7 and ATG5 was all decreased in cells treated with LINC00470, and down-regulated PTEN expression was observed in chemo-resistant cells, while the expression of PTEN was rescued by the transfection of shMETTL3 into chemo-resistant cells. Moreover, the knockdown of METTL3 also restored the normal level of PTEN m6 A modification and LINC00470 expression in chemo-resistant cells. In conclusion, our results demonstrated the molecular mechanism underlying the effect of LINC00470 on CML by reducing the PTEN stability via RNA methyltransferase METTL3, thus leading to the inhibition of cell autophagy while promoting chemoresistance in CML.


Subject(s)
Autophagy , Biomarkers, Tumor/metabolism , Drug Resistance, Neoplasm , Gene Expression Regulation, Neoplastic , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Methyltransferases/metabolism , RNA, Long Noncoding/genetics , Animals , Antineoplastic Agents/pharmacology , Apoptosis , Biomarkers, Tumor/genetics , Cell Proliferation , Humans , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Male , Methyltransferases/genetics , Mice , Mice, Inbred BALB C , Mice, Nude , PTEN Phosphohydrolase , Tumor Cells, Cultured , Xenograft Model Antitumor Assays
11.
Mol Med Rep ; 18(1): 723-732, 2018 Jul.
Article in English | MEDLINE | ID: mdl-29845205

ABSTRACT

The aim of the present study was to investigate the effect of co­culture with amniotic epithelial cells (AECs) on the biological characteristics of amniotic mesenchymal stem cells (AMSCs), to compare the expression of C­X­C motif chemokine receptor 4 (CXCR4) in co­cultured AMSCs and to investigate the roles of the stromal cell­derived factor­1 (SDF­1)/CXCR4 axis in the homing and migration of AMSCs. AMSCs were isolated from human amniotic membranes, purified and then differentiated into osteoblasts and adipocytes in vitro, which was verified by von Kossa Staining and Oil Red O staining. Cell viability was measured by Cell Counting kit­8 and trypan blue assays at 24, 48 and 72 h, the expression of CXCR4 was analyzed by immunofluorescence­based flow cytometry and reverse transcription­quantitative polymerase chain reaction, and the migration ability of AMSCs in vitro was observed by a migration assay. The results demonstrated that cell viability (at 48 and 72 h) and survival (at 24, 48 and 72 h) in the co­culture and serum groups were higher compared with the serum­free group. Furthermore, CXCR4 mRNA and protein expression, and migration along the SDF­1 gradient, in the co­culture and serum­free groups were higher compared with the serum group. Overall, the results indicated that AMSCs co­cultured with AECs exhibited enhanced proliferation activity and survival rate. In conclusion, the present study demonstrated that co­culture of AMSCs with AECs upregulated CXCR4 on the surface of AMSCs and enhanced the migration ability of AMSCs in vitro. This result may improve the directional migration and homing ability of AMSCs, as well as provide a theoretical basis for the application of AMSCs in clinical practice as a novel strategy to increase the success of hematopoietic stem cell transplantation.


Subject(s)
Adipocytes/metabolism , Amnion/metabolism , Cell Differentiation , Cell Movement , Epithelial Cells/metabolism , Mesenchymal Stem Cells/metabolism , Osteoblasts/metabolism , Adipocytes/cytology , Adult , Amnion/cytology , Chemokine CXCL12/metabolism , Coculture Techniques , Epithelial Cells/cytology , Female , Humans , Mesenchymal Stem Cells/cytology , Osteoblasts/cytology , Receptors, CXCR4/metabolism
12.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-941642

ABSTRACT

OBJECTIVE@#To analyze the association between sleep duration and athletic performance, and provide scientific basis to improve the 50 m and endurance performance in children and adolescents.@*METHODS@#All the 119 462 subjects aged 9-15 years in both genders were sampled from 2014 National Physical Fitness and Health Surveillance by using stratified random cluster sampling method, to measure the height, weight, 50 meters and endurance performance and investigate sleep duration with questionnaire. Their body mass indexes (BMI) were calculated and the students' 50 m, endurance run scores and sleep durations were assessed. Binary Logistic regression was used to analyze the difference between the different sleep groups, and multifactor Logistic regression was used to analyze the relationship between the sleep condition and athletic performance.@*RESULTS@#The prevalence of insufficient sleep was 94.67% in the total subjects, the prevalence was higher among the girls (95.26%)than the boys (94.09%, χ2=80.99, P<0.001), and higher among the urban (95.41%) than the rural students(93.93%, χ2=128.48, P<0.001).The children with sufficient sleep had better performance in 50 m and endurance run scores( χ250 m=10.10, P50 m<0.01; χ2endurance run=21.76, P<0.001). Logistic regression analysis after controlling the gender, area, grade and BMI showed that children with adequate sleep showed better results(OR50 m=1.14, 95%CI50 m=1.05-1.23, P50 m<0.01; ORendurance run=1.21, 95%CIendurance run=1.11-1.31, Pendurance run<0.001). As for gender, the excellent rates of 50 m and endurance run scores in the boys with adequate sleep were higher (P<0.001), but there were no significant difference in 50 m and endurance run excellent rates in the girls of different sleep conditions. The excellent rates of 50 m and endurance run in the urban children and the endurance rate in the rural children and adolescents with adequate sleep were higher than those with insufficient sleep (P<0.01) while there were no significant difference in the 50 m excellent rates between the different sleep groups in rural areas. The 50 m and endurance run excellent rates of the children and adolescents with adequate sleep in each grade were higher than those of the children in the same grade with insufficient sleep (Pprimary students' endurance performance<0.001, and the rest P<0.05). Children and adolescents with normal BMI and overweight who slept well had better performance in 50 m (P<0.05). The endurance run excellent rate of children and adolescents with adequate sleep in each BMI group was higher than that in children and adolescents with insufficient sleep in the same BMI group (Pmalnutrition<0.01, Pnormal<0.01, Poverweight<0.05, Pobesity<0.05). The children and adolescents were divided into different groups according to the sleep duration,the one who slept less than 7 hours had lower 50 m excellent rate than the other groups with longer sleeping duration (P<0.01) and the rate in the ones who slept more than 9 hours was the highest (P<0.001).The endurance excellent rate in the children and adolescents who slept more than 9 hours was significantly higher than that in the other groups (P<0.001).There was no significant dose-response relationship in excellent rates and sleep durations.@*CONCLUSION@#The prevalence of insufficient sleep has increased, and the sleep condition in children and adolescents is severe. Children and adolescents with sufficient sleep have better athletic performance, so we should strengthen the prevention and control of the lack of sleep in children and adolescents.


Subject(s)
Adolescent , Child , Female , Humans , Male , Body Mass Index , Body Weight , Logistic Models , Nutritional Status , Overweight , Physical Fitness , Prevalence , Rural Population , Sleep , Students , Surveys and Questionnaires
13.
Opt Express ; 25(4): 4180-4189, 2017 Feb 20.
Article in English | MEDLINE | ID: mdl-28241623

ABSTRACT

We present a high-precision hybrid imprinting method to fabricate multi-layer micro-optical structures on nonplanar substrates using a custom-built vacuum imprinting system; with the application of kinematic couplings that align the flexible stamps in all six degrees of freedom, a cross-layer pattern registration precision of 400 nm has been achieved on nonplanar substrates. To demonstrate the precision and feasibility of the new process and instrument, we have designed and fabricated a multi-layer artificial compound eye (ACE) for multispectral imaging. The shapes and sizes of all 12 micro-lenses on the ACE are optimized and integrated with different color filers (red, green and blue) so that the light from different channels and of different spectral contents will focus to the same plane, where the photodetector is located. Next, the multi-layer ACE is installed in a portable optical system for simultaneous multispectral imaging, i.e., to perform pattern detection by looking at specific frequency windows. Imaging experiments are devised and performed on (1) color blindness test cards, (2) space image, and (3) breast and gastric tumor samples. The results confirm the system's capabilities of frequency separation, extraction of hidden information, and tumor identification.

14.
Nan Fang Yi Ke Da Xue Xue Bao ; 36(10): 1435-1439, 2016 Oct 20.
Article in Chinese | MEDLINE | ID: mdl-27777212

ABSTRACT

OBJECTIVE: To construct the KbvR gene of LuxR family deletion mutant and complementation strains from Klebsiella pneumoniae NTUH-K2044 and analyze the effect of KbvR on bacterial growth, biofilm formation and capsular synthesis. METHODS: A KbvR gene deletion mutant strain was constructed using the suicide vector pKO3-Km, and the gene fragment including KbvR coding region, promoter area and transcription termination area were amplified and cloned into pGEM-T-easy plasmid to construct KbvR complementation strain. The growth curves of the wild-type strain, KbvR gene deletion mutant strain and complementation strain were observed to assess the effect of KbvR on bacterial growth. Crystal violet staining method was used to measure the effect of KbvR on biofilm formation; the effect of KbvR on capsular synthesis was detected using string test, centrifugal test and RT-PCR. RESULTS: The KbvR deletion mutant and complementation strains were constructed successfully. KbvR gene did not affect the growth of the bacteria, but biofilm formation and capsular synthesis were attenuated in KbvR deletion mutant strain. CONCLUSION: As a transcription factor of the LuxR family orphans of the quorum sensing system, KbvR positively regulates bacterial biofilm formation by affecting capsular synthesis.


Subject(s)
Bacterial Capsules , Bacterial Proteins/metabolism , Biofilms , Klebsiella pneumoniae/cytology , Gene Deletion , Plasmids , Promoter Regions, Genetic
15.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-256581

ABSTRACT

<p><b>OBJECTIVE</b>To construct the KbvR gene of LuxR family deletion mutant and complementation strains from Klebsiella pneumoniae NTUH-K2044 and analyze the effect of KbvR on bacterial growth, biofilm formation and capsular synthesis.</p><p><b>METHODS</b>A KbvR gene deletion mutant strain was constructed using the suicide vector pKO3-Km, and the gene fragment including KbvR coding region, promoter area and transcription termination area were amplified and cloned into pGEM-T-easy plasmid to construct KbvR complementation strain. The growth curves of the wild-type strain, KbvR gene deletion mutant strain and complementation strain were observed to assess the effect of KbvR on bacterial growth. Crystal violet staining method was used to measure the effect of KbvR on biofilm formation; the effect of KbvR on capsular synthesis was detected using string test, centrifugal test and RT-PCR.</p><p><b>RESULTS</b>The KbvR deletion mutant and complementation strains were constructed successfully. KbvR gene did not affect the growth of the bacteria, but biofilm formation and capsular synthesis were attenuated in KbvR deletion mutant strain.</p><p><b>CONCLUSION</b>As a transcription factor of the LuxR family orphans of the quorum sensing system, KbvR positively regulates bacterial biofilm formation by affecting capsular synthesis.</p>


Subject(s)
Bacterial Capsules , Bacterial Proteins , Metabolism , Biofilms , Gene Deletion , Klebsiella pneumoniae , Cell Biology , Plasmids , Promoter Regions, Genetic
16.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 3): m302, 2012 Mar 01.
Article in English | MEDLINE | ID: mdl-22412444

ABSTRACT

In the title compound, [Hg(C(42)H(38)N(4)O(2))](PF(6))(2)·2CH(3)CN, the Hg(II) cation lies on a twofold axis which is also the inter-nal symmetry element of the complete cationic complex. The Hg(II) cation is coordinated by two symmetry-related C(carbene) atoms [Hg-C = 2.058 (9) Å] in a nearly linear geometry, with a C-Hg-C angle of 175.8 (5)°. There are weak inter-molecular C-H⋯F inter-actions in the crystal packing between an F atom of a hexa-fluoridophosphate anion and a -CH(2)- group of the bis-N-heterocyclic carbene ligand.

17.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 3): m350, 2012 Mar 01.
Article in English | MEDLINE | ID: mdl-22412477

ABSTRACT

The asymmetric unit of the title compound, [Cu(2)(C(12)H(9)O(2))(4)(C(3)H(7)NO)(2)], contains two independent centrosymmetric dinuclear copper(II) complexes. The central paddle-wheel units are formed by four bridging bidentate naphthalene-1-acetate ligands with two dimethyl-formamide ligands in the axial positions. The unique Cu(II) ions have slightly distorted square-pyramidal coordination geometries. One of the naphthalene rings is disordered over two sets of sites, with refined occpancies of 0.535 (4) and 0.465 (4).

18.
J Opt Soc Am A Opt Image Sci Vis ; 24(10): A1-6, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17912282

ABSTRACT

The enhancement and confinement characteristics of the local field in the two-dimensional (2D) subwavelength-size series cavities structure are investigated numerically by using the boundary integral method. The series cavities are built of two pieces of finite silver thin slabs with subwavelength corrugations on their inner boundaries, set in a face-to-face arrangement with a separating space, and the central part is a narrow channel (NC). We calculate the average amplitude of the local field in the NC as a function of the wavelength for exploring the influence of the structural parameters and demonstrate the amplitude distribution of the magnetic field in the structure and the cross-section distributions of the local field in the NC region along both the longitudinal axis direction and the transverse directions. The simulations show that the local field in the NC has significant enhancement, up to 2 orders of magnitude, of the incident light field, and the local light field is confined to a small region less than one fifth of the resonant wavelength in the longitudinal direction and one twentieth of the resonant wavelength in the lateral direction. Replacing the metallic material of the cavity walls with the semiconductor germanium leads to the complete disappearance of the enhancement of the local field. It is clearly shown that surface plasmon polaritons on the metal play a critical role for this enhancement phenomenon. The influences of various geometric parameters on the resonant wavelength and the peak value of the average amplitude of the local field are extensively investigated.


Subject(s)
Models, Theoretical , Nanostructures , Radiometry/methods , Surface Plasmon Resonance/methods , Computer Simulation , Light , Scattering, Radiation
19.
J Opt Soc Am A Opt Image Sci Vis ; 24(2): 512-6, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17206267

ABSTRACT

The common focusing characteristics of a cylindrical microlens with a long focal depth and under a given multiple-wavelength illumination are analyzed based on the boundary element method (BEM). The surface-relief profile of a finite-substrate-thickness microlens with a long focal depth is presented. Its focusing performances, such as the common extended focal depth (CEFD), the spot size, and the diffraction efficiency, are numerically studied in the case of TE polarization. The results show that the CEFD of the microlens increases initially, reaches a peak value, and then decreases with increasing preset focal depth. Two modified profiles of a finite-substrate-thickness cylindrical microlens are proposed for enlarging the CEFD. The rigorous numerical results indicate that the modified surface-relief structures of a cylindrical microlens can successfully modulate the optical field distribution to achieve longer CEFD, higher transverse resolution, and higher diffraction efficiency simultaneously, compared with the prototypical microlens. These investigations may provide useful information for the design and application of micro-optical elements in various multiwavelength optical systems.

SELECTION OF CITATIONS
SEARCH DETAIL
...