407 research outputs found

    Identification and subcellular localization of a novel Cu,Zn superoxide dismutase of Mycobacterium tuberculosis

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    AbstractPeriplasmic copper, zinc superoxide dismutases (Cu,ZnSOD) of several Gram-negative pathogens have been shown to play an important role in protection against exogenous superoxide radicals and in determining virulence of the pathogens. Here we report the cloning and characterization of the sodC gene, encoding Cu,ZnSOD, from the Gram-positive Mycobacterium tuberculosis. The predicted protein sequence contains 240 amino acids with a putative signal peptide at the N-terminus and shows ∼25% identity to other bacterial sodC. Recombinant proteins of a full-length sodC and a truncated form lacking the putative signal peptide were overexpressed in Escherichia coli and affinity purified. Renatured recombinant M. tuberculosis sodC protein possessed characteristics of a Cu,ZnSOD. Immunoblotting with an antiserum against the recombinant M. tuberculosis Cu,ZnSOD allowed detection of a single polypeptide in the lysate of M. tuberculosis. This polypeptide has a similar size as the recombinant protein without the putative signal peptide indicating that the endogenous Cu,ZnSOD in M. tuberculosis might be processed and secreted. Furthermore, immunogold electron microscopic image showed that Cu,ZnSOD is located in the periphery of M. tuberculosis. The enzymatic activity and subcellular localization of this novel Cu,ZnSOD suggest that it may play a role in determining virulence of M. tuberculosis

    Multiple upstream modules regulate zebrafish myf5 expression

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    BACKGROUND: Myf5 is one member of the basic helix-loop-helix family of transcription factors, and it functions as a myogenic factor that is important for the specification and differentiation of muscle cells. The expression of myf5 is somite- and stage-dependent during embryogenesis through a delicate regulation. However, this complex regulatory mechanism of myf5 is not clearly understood. RESULTS: We isolated a 156-kb bacterial artificial chromosome clone that includes an upstream 80-kb region and a downstream 70-kb region of zebrafish myf5 and generated a transgenic line carrying this 156-kb segment fused to a green fluorescent protein (GFP) reporter gene. We find strong GFP expression in the most rostral somite and in the presomitic mesoderm during segmentation stages, similar to endogenous myf5 expression. Later, the GFP signals persist in caudal somites near the tail bud but are down-regulated in the older, rostral somites. During the pharyngula period, we detect GFP signals in pectoral fin buds, dorsal rostral myotomes, hypaxial myotomes, and inferior oblique and superior oblique muscles, a pattern that also corresponds well with endogenous myf5 transcripts. To characterize the specific upstream cis-elements that regulate this complex and dynamic expression pattern, we also generated several transgenic lines that harbor various lengths within the upstream 80-kb segment. We find that (1) the -80 kb/-9977 segment contains a fin and cranial muscle element and a notochord repressor; (2) the -9977/-6213 segment contains a strong repressive element that does not include the notochord-specific repressor; (3) the -6212/-2938 segment contains tissue-specific elements for bone and spinal cord; (4) the -2937/-291 segment contains an eye enhancer, and the -2937/-2457 segment is required for notochord and myocyte expression; and (5) the -290/-1 segment is responsible for basal transcription in somites and the presomitic mesoderm. CONCLUSION: We suggest that the cell lineage-specific expression of myf5 is delicately orchestrated by multiple modules within the distal upstream region. This study provides an insight to understand the molecular control of myf5 and myogenesis in the zebrafish

    Toona sinensis

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    Toona sinensis leaf (TSL) is commonly used as a vegetable and in spice in Asia. In this study, feeding with aqueous extract of TSL (TSL-A) alleviated oxidative stress and recovered the motility and functions of sperm in rats under oxidative stress. Protein expressions in testes identified by proteomic analysis and verified by Western blot demonstrated that TSL-A not only downregulated the level of glutathione transferase mu6 (antioxidant system), heat shock protein 90 kDa-β (protein misfolding repairing system), cofilin 2 (spermatogenesis), and cyclophilin A (apoptosis) but also upregulated crease3-hydroxy-3-methylglutaryl-coenzyme A synthase 2 (steroidogenesis), heat shock glycoprotein 96, and pancreatic trypsin 1 (sperm-oocyte interaction). These results indicate that TSL-A promotes the functions of sperm and testes via regulating multiple testicular proteins in rats under oxidative stress, suggesting that TSL-A is a valuable functional food supplement to improve functions of sperm and testes for males under oxidative stress

    Schwann Cell Migration Induced by Earthworm Extract via Activation of PAs and MMP2/9 Mediated through ERK1/2 and p38

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    The earthworm, which has stasis removal and wound-healing functions, is a widely used Chinese herbal medicine in China. Schwann cell migration is critical for the regeneration of injured nerves. Schwann cells provide an essentially supportive activity for neuron regeneration. However, the molecular migration mechanisms induced by earthworms in Schwann cells remain unclear. Here, we investigate the roles of MAPK (ERK1/2, JNK and p38) pathways for earthworm-induced matrix-degrading proteolytic enzyme (PAs and MMP2/9) production in Schwann cells. Moreover, earthworm induced phosphorylation of ERK1/2 and p38, but not JNK, activate the downstream signaling expression of PAs and MMPs in a time-dependent manner. Earthworm-stimulated ERK1/2 and p38 phosphorylation was attenuated by pretreatment with U0126 and SB203580, resulting in migration and uPA-related signal pathway inhibition. The results were confirmed using small interfering ERK1/2 and p38 RNA. These results demonstrated that earthworms can stimulate Schwann cell migration and up-regulate PAs and MMP2/9 expression mediated through the MAPK pathways, ERK1/2 and p38. Taken together, our data suggests the MAPKs (ERK1/2, p38)-, PAs (uPA, tPA)-, MMP (MMP2, MMP9) signaling pathway of Schwann cells regulated by earthworms might play a major role in Schwann cell migration and nerve regeneration

    Orderly arranged NLO materials on exfoliated layeredtemplates based on dendrons with alternating moietiesat the periphery†

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    Nonlinear optical dendrons with alternating terminal groups of the stearyl group (C18) and chromophorewere prepared through a convergent approach. These chromophore-containing dendrons were used asthe intercalating agents for montmorillonite via an ion-exchange process. An orderly exfoliatedmorphology is obtained by mixing the dendritic structure intercalated layered silicates with a polyimide.As a result, optical nonlinearity, i.e. the Pockels effect was observed for these nanocomposites withoutresorting to the poling process. EO coefficients of 9–22 pm V 1 were achieved despite that relativelylow NLO densities were present in the nanocomposites, particularly for the samples comprising thedendrons with alternating moieties. In addition, the hedging effects of the stearyl group on the selfalignmentbehavior, electro-optical (EO) coefficient and temporal stability of the dendron-intercalatedmontmorillonite/polyimide nanocomposites were also investigated

    RSC96 Schwann Cell Proliferation and Survival Induced by Dilong through PI3K/Akt Signaling Mediated by IGF-I

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    Schwann cell proliferation is critical for the regeneration of injured nerves. Dilongs are widely used in Chinese herbal medicine to remove stasis and stimulate wound-healing functions. Exactly how this Chinese herbal medicine promotes tissue survival remains unclear. The aim of the present study was to investigate the molecular mechanisms by which Dilong promote neuron regeneration. Our results show that treatment with extract of Dilong induces the phosphorylation of the insulin-like growth factor-I (IGF-I)-mediated phosphatidylinositol 3-kinase/serine-threonine kinase (PI3K/Akt) pathway, and activates protein expression of cell nuclear antigen (PCNA) in a time-dependent manner. Cell cycle analysis showed that G1 transits into the S phase in 12–16 h, and S transits into the G2 phase 20 h after exposure to earthworm extract. Strong expression of cyclin D1, cyclin E and cyclin A occurs in a time-dependent manner. Small interfering RNA (siRNA)-mediated knockdown of PI3K significantly reduced PI3K protein expression levels, resulting in Bcl2 survival factor reduction and a marked blockage of G1 to S transition in proliferating cells. These results demonstrate that Dilong promotes the proliferation and survival of RSC96 cells via IGF-I signaling. The mechanism is mainly dependent on the PI3K protein

    Impact of Irradiation on the Pharmacokinetics and Biotransformation of Tamoxifen.

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    BACKGROUND: The optimal procedure for combining radiotherapy (RT) with tamoxifen treatment is controversial as RT may alter the pharmacokinetics and biotransformation of tamoxifen. The present study investigated this potential interaction by assessing the pharmacokinetics of tamoxifen during concurrent and sequential RT. METHOD: Plasma tamoxifen concentration was measured in rats with or without RT 2.0 Gy (RT2.0Gy) or 0.5 Gy (RT0.5Gy) with ultra-high-performance liquid chromatography-tandem mass spectrometry after tamoxifen administration (10 mg/kg, p.o., n = 6). Tamoxifen was either administered 1 h after RT (concurrent condition) or 24 h after RT (sequential condition). RESULTS: Pharmacokinetic data analysis demonstrated that the area under the curve (AUC) and half-life of tamoxifen were 2,004 ± 241 h ng/ml and 6.23 ± 1.21 h, respectively, after tamoxifen administration (10 mg/kg, p.o.). The respective conversion rate of 4-hydroxytamoxifen, N-desmethytamoxifen, and endoxifen for tamoxifen metabolism was 20%, 16%, and 5%. The AUC value of tamoxifen in the RT0.5Gy group was 1.5- to 1.7-fold higher than in the sham and RT2.0Gy groups. The relative bioavailability of tamoxifen at concurrent RT0.5Gy and RT2.0Gy groups ranged from 127% to 202% and from 71% to 152%, respectively. The magnitude of endoxifen, which converted from 4-hydroxytamoxifen and N-desmethyltamoxifen, increased 3- to 5-fold in the concurrent RT groups. By contrast, the AUC of tamoxifen decreased by roughly 24% in the sequential RT2.0Gy group. The conversion ratio of endoxifen was four times higher than that in the sequential RT2.0Gy group compared with rats not exposed to RT. CONCLUSION: The current study provides advanced pharmacokinetic data to confirm the interaction between RT and hormone therapy. Our findings indicate that RT facilitates the metabolism of tamoxifen to active metabolites and thus imply that combination RT-tamoxifen has potential benefits for the treatment of hormone-dependent breast cancer

    Efficacy of Femarelle for the treatment of climacteric syndrome in postmenopausal women: An open label trial

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    AbstractObjectiveTo assess the effects of 2 months of treatment with Femarelle for climacteric syndrome in Taiwanese postmenopausal women.Materials and methodsA multi-center, open-label trial of 260 postmenopausal women, age ≥ 45 years with vasomotor symptoms. Women were enrolled after obtaining a detailed medical history and a thorough physical examination. They then received Femarelle (640 mg/d) twice daily for 8 weeks. The primary outcome was the changes in the frequency and severity of hot flushes from baseline to 4 weeks (1 month) and 8 weeks (2 months). Changes of general climacteric syndrome were assessed using a modified climacteric scale designed by Greene.ResultsThe frequency and severity of hot flushes were significantly improved with Femarelle use (p < 0.001). After 8 weeks of treatment, the percentage of women with various climacteric syndromes was reduced (from 100% to 20.9% for hot flushes, from 97.7% to 87.9% for psychological symptoms, from 93.8% to 78.8% for somatic symptoms, and from 87.8% to 74.9% for sexual symptoms). General climacteric syndrome scores also significantly decreased, from 20.8 ± 0.7 at the time of enrollment to 12.9 ± 0.7 after 8 weeks of Femarelle treatment (p < 0.0001). Participants experienced improvement of various climacteric symptoms and signs after 8 weeks of treatment (75.1% for hot flushes, 68.7% for psychological symptoms, 70.6% for somatic symptoms, and 69.0% for sexual problems respectively). After 4 weeks and 8 weeks of treatment with Femarelle, patients showed statistically significant improvement in climacteric symptoms (p < 0.0001). Three women (1.2%) withdrew from the study after 4 weeks of treatment due to adverse effects.ConclusionFemarelle significantly improved climacteric symptoms in Taiwanese postmenopausal women. However, further evaluation is needed regarding the safety of long-term consumption
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