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991.
992.
Qiu J Luo M Wang J Dong J Li H Leng B Zhang Q Dai X Zhang Y Niu X Deng X 《FEMS microbiology letters》2011,324(2):147-155
Staphylococcus aureus is a versatile pathogen that can cause life-threatening infections. The growing emergence of methicillin-resistant S.?aureus strains and a decrease in the discovery of new antibiotics warrant the search for new therapeutic targets to combat infections. Staphylococcus aureus produces many extracellular virulence factors that contribute to its pathogenicity. Therefore, targeting bacterial virulence as an alternative strategy to the development of new antimicrobials has gained great interest. α-Toxin is a 33.2-kDa, water-soluble, pore-forming toxin that is secreted by most S.?aureus strains. α-Toxin is essential for the pathogenesis of pneumonia, as strains lacking α-toxin display a profound defect in virulence. In this report, we demonstrate that isoalantolactone (IAL), a naturally occurring compound found in Inula helenium (Compositae), has no anti-S.?aureus activity as per MIC evaluation in vitro. However, IAL can markedly inhibit the expression of α-toxin in S.?aureus at very low concentrations. Furthermore, the in vivo data indicate that treatment with IAL protects mice from S.?aureus pneumonia. 相似文献
993.
Chen?Mao Ru-Yan?Liao Li-Xin?Qiu Xi-Wen?Wang Hong?Ding Qing?ChenEmail author 《Molecular biology reports》2011,38(4):2219-2223
Epidemiologic studies have evaluated the association between BRAF mutations and resistance to the treatment of anti-EGFR monoclonal antibodies (MoAb) in patients with metastatic colorectal
cancer (mCRC). However, the results are still inconclusive. To derive a more precise estimation of the relationship, we performed
this meta-analysis. A total of 11 studies were included in the final meta-analysis. There were seven studies for unselected
mCRC patients and four studies for patients with wild type KRAS mCRC. Among unselected mCRC patients, BRAF V600E mutation was detected in 48 of 546 primary tumors (8.8%). The objective response rate (ORR) of patients with mutant
BRAF was 29.2% (14/48), whereas the ORR of patients with wild-type BRAF was 33.5% (158/472).The overall RR for ORR of mutant BRAF patients over wild-type BRAF patients was 0.86 (95% CI = 0.57–1.30; P = 0.48). For patients with KRAS wild-type mCRC, BRAF V600E mutation was detected in 40 of 376 primary tumors (10.6%). The ORR of patients with mutant BRAF was 0.0% (0/40), whereas the ORR of patients with wild-type BRAF was 36.3% (122/336). The pooled RR of mutant BRAF patients over wild-type BRAF patients was 0.14 (95% CI = 0.04–0.53; P = 0.004). In conclusion, this meta-analysis provides evidence that BRAF V600E mutation is associated with lack of response in wild-type KRAS mCRC treated with anti-EGFR MoAbs. BRAF mutation may be used as an additional biomarker for the selection of mCRC patients who might benefit from anti-EGFR MoAbs
therapy. 相似文献
994.
Yifeng Miao Yongming Qiu Yuchang Lin Zengli Miao Jing Zhang Xiaojie Lu 《Molecular biology reports》2011,38(5):3235-3242
Pyruvate, an endogenous metabolite of glycolysis, is an anti-toxicity agent. Recent studies have suggested possible roles
for pyruvate in protecting CNS neurons from excitotoxic and metabolic insults. Utilizing cultures derived from embryonic rat
cortex, the studies presented in this paper indicate that an astroglia-mediated mechanism is involved in the neuroprotective
effects of pyruvate against glutamate toxicity. Glutamate-induced toxicity could be reversed by pyruvate in a mixed culture
of cortex cells. Importantly, in pure neuronal cultures from the same tissue, pyruvate failed to protect against glutamate
toxicity. Addition of astroglia to the pure neuronal cultures restores the ability of pyruvate to protect neurons from glutamate-induced
toxicity. Our results further suggest that pyruvate can induce glia to up-regulate the synthesis of glutathione (GSH), an
antioxidant that protects cells from toxins such as free radicals. Taken together, our data suggest that astroglia in mixed
cultures are essential for mediating the effects of pyruvate, revealing a novel mechanism by which pyruvate, an important
intermediate of tricarboxylic acid cycle in the body, may act to protect neurons from damage during insults such as brain
ischemia. 相似文献
995.
Chao Wang Shouqiang Cao Xinxin Tie Bo Qiu Anhua Wu Zhihong Zheng 《Molecular biology reports》2011,38(1):523-530
We have investigated the possibility that photoexcited titanium dioxide (TiO2) could inhibit the growth of malignant cells. We studied the anti-glioma effects of nano-TiO2 excited with ultraviolet A (UVA) irradiation both in vitro and in vivo. Transmission electron microscopy demonstrated that
glioma cells take up TiO2 by phagocytosis, and vital staining revealed that TiO2 alone has no effect on glioma cell proliferation. However, if TiO2 was combined with UVA irradiation the proliferation rate was decreased significantly compared to controls (P < 0.05). RT–PCR suggested that TiO2 induction of glioma cell apoptosis is associated with changes in the expression of genes encoding Bcl-2 family members. We
then investigated the in vivo antitumor effects of combined TiO2 plus UVA treatment of established glioma tumors. TiO2 plus UVA led to pronounced areas of necrosis, elevated indices of apoptosis, delayed tumor growth, and increased survival
compared with the TiO2-alone control group (P < 0.001). Log-rank survival analysis showed that median survival duration was prolonged (P < 0.001). These findings suggest that nano-TiO2 based photodynamic therapy has potential in the treatment of glioma. 相似文献
996.
Xu ZE Chen Y Huang A Varghese Z Moorhead JF Yan F Powis SH Li Q Ruan XZ 《American journal of physiology. Renal physiology》2011,301(4):F713-F722
Both lipids and inflammation play important roles in the progression of kidney disease. This study was designed to investigate whether inflammation exacerbates lipid accumulation via LDL receptors (LDLr), thereby causing renal injury in C57BL/6J mice, apolipoprotein E (ApoE) knockout (KO) mice, and ApoE/CD36/scavenger receptor A triple KO mice. The mice were given a subcutaneous casein injection to induce inflammatory stress. After 14 wk, terminal blood samples were taken for renal function, lipid profiles, amyloid A (SAA), and IL-6 assays. Lipid accumulation in kidneys was visualized by oil red O staining. Fibrogenic molecule expression in kidneys was examined. There was a significant increase in serum SAA and IL-6 in the all casein-injected mice compared with respective controls. Casein injection reduced serum total cholesterol, LDL cholesterol, and HDL cholesterol and caused lipid accumulation in kidneys from three types of mice. The expression of LDLr and its regulatory proteins sterol-responsive element-binding protein (SREBP) 2 and SREBP cleavage-activating protein (SCAP) were upregulated in inflamed mice compared with controls. Casein injection induced renal fibrosis accompanied by increased expression of fibrogenic molecules in the triple KO mice. These data imply that inflammation exacerbates lipid accumulation in the kidney by diverting lipid from the plasma to the kidney via the SCAP-SREBP2-LDLr pathway and causing renal injury. Low blood cholesterol levels, resulting from inflammation, may be associated with high risk for chronic renal fibrosis. 相似文献
997.
Scutellarin (Scu), the main bioactive component of Erilgeron breviscapus, protects the brain against ischemic damages. To explore the therapeutic mechanism of Scu, we investigated the impact of
Scu on sodium current (I
Na) of freshly isolated mouse hippocampal CA1 neurons using the whole-cell patch clamp technique. Results showed that Scu inhibited
I
Na in concentration- and holding potential-dependent manners. At 50 μM, Scu markedly shifted the steady state inactivation curve
of I
Na towards a more negative potential, slowed down the recovery of I
Na from inactivation state, and elicited a frequency-dependent block of I
Na. The shape of the current–voltage (I–V) curve and the steady state activation curve of I
Na were unaffected by Scu treatment. These findings suggest that Scu is capable of inhibiting I
Na in neurons through predominantly affecting the inactivated state of I
Na. Inhibition of Na+ channels provides a novel pharmacological basis for the anti-ischemic application of Scu. 相似文献
998.
Geetanjali KharmatePadmesh S. Rajput Heather L. WattRishi K. Somvanshi Nicole ChaudhariXiaofan Qiu Ujendra Kumar 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2011,1813(6):1172-1189
Epidermal growth factor (EGF) regulates normal and tumor cell proliferation via epidermal growth factor receptor (EGFR) phosphorylation, homo- or heterodimerization and activation of mitogen-activated protein kinases (MAPKs) and PI3K/AKT cell survival pathways. In contrast, SST via activation of five different receptor subtypes inhibits cell proliferation and has been potential target in tumor treatment. To gain further insight for the effect of SSTRs on EGFR activated signaling, we determine the role of SSTR1 and SSTR1/5 in human embryonic kidney (HEK) 293 cells. We here demonstrate that cells transfected with SSTR1 or SSTR1/5 negatively regulates EGF mediated effects attributed to the inhibition of EGFR phosphorylation, MAPKs as well as the cell survival signaling. Furthermore, SSTR effects were significantly enhanced in cells when EGFR was knock down using siRNA or treated with selective antagonist (AG1478). Most importantly, the presence of SSTR in addition to modulating signaling pathways leads to the dissociation of the constitutive and EGF induced heteromeric complex of EGFR/ErbB2. Furthermore, cells cotransfected with SSTR1/5 display pronounced effect of SST on the signaling and dissociation of the EGFR/ErbB2 heteromeric complex than the cells expressing SSTR1 alone. Taken together this study provides the first evidence that the presence of SSTR controls EGF mediated cell survival pathway via dissociation of ErbB heteromeric complex. We propose that the activation of SSTR and blockade of EGFR might serve novel therapeutic approach in inhibition of tumor proliferation. 相似文献
999.
Trichoderma harzianum SQR-T037 rapidly degrades allelochemicals in rhizospheres of continuously cropped cucumbers 总被引:3,自引:0,他引:3
Chen L Yang X Raza W Li J Liu Y Qiu M Zhang F Shen Q 《Applied microbiology and biotechnology》2011,89(5):1653-1663
To alleviate the stress of continuous cropping for cucumber continuous cropping (CCC) system, a beneficial fungus Trichoderma harzianum SQR-T037 (SQR-T037) was isolated and applied to soil to degrade allelochemicals exuded from cucumber plants in a Rhizobox
experiment. The following phenolic acids (PAs), classified as allelochemicals, were isolated and identified from cucumber
rhizospheres: 4-hydroxybenzoic acid, vanillic acid, ferulic acid, benzoic acid, 3-phenylpropionic acid, and cinnamic acid.
Mixed PAs added in potato dextrose broth, each with 0.2 gram per liter, were completely degraded by SQR-T037 after 170 h of
incubation. In Rhizobox experiments, inoculation of SQR-T037 in the CCC soil also degraded the PAs exuded from cucumber plant
roots. This degradation was 88.8% for 4-hydroxybenzoic acid, 90% for vanillic acid, 95% for benzoic acid, and 100% for ferulic
acid, 3-phenylpropionic acid, and cinnamic acid at 45 days after plantation. Simultaneously, a significant (p ≥ 0.05) decrease in the disease index of Fusarium wilt and an increase in dry weights of cucumber plants were obtained in
pot experiments by application of SQR-T037. This was mostly attributed to degradation of PAs exuded from cucumber roots in
CCC soil by SQR-T037 and alleviation of the allelopathic stress. Application of beneficial microorganisms, such as SQR-T037
that biodegrades allelochemicals, is a highly efficient way to resolve the problems associated with continuous cropping system. 相似文献
1000.
The aim of the present work was to determine and compare the degradation of acetate in a Chinese rice field soil at 25°C and 50°C, respectively, and to identify specifically the active organisms involved in syntrophic acetate oxidation. Soil was preincubated anaerobically for 30 days to reduce alternative electron acceptors other than CO(2). The [2-(13)C] acetate (99% (13)C) was added twice: 0 day and 19 days after preincubation. Addition of [2-(13)C] acetate resulted in an immediate increase of (13)C labeled CH(4) but non-labeling of CO(2) at 25°C. The methanogen community was dominated by Methanosarcinaceae and Methanocellales at 25°C. In contrast, the addition of [2-(13)C] acetate at 50°C resulted in a rapid increase of (13)CO(2). The (13)C labeling of CH(4) gradually increased and reached a similar value to CO(2) (13% (13)C) at the end of incubation (40 days). Nearly all archaeal 16S rRNA genes detected at 50°C belonged to hydrogenotrophic Methanocellales. DNA-based stable isotope probing analysis revealed that the organisms related to Thermacetogenium lineage and the unclassified Thermoanaerobacteraceae group were intensively labeled with (13)C in the incubations at 50°C. Thus, acetate was converted to CH(4) and CO(2) through aceticlastic methanogenesis at 25°C, while syntrophic acetate oxidation occurred at 50°C. 相似文献