Smad2/3a对斑马鱼神经嵴细胞标记基因crestin表达的影响

目的 探讨Smad2/3a对脊椎动物神经嵴细胞发育的影响。方法 通过在斑马鱼胚胎单细胞时期显微注射smad2/3吗啉环修饰的反义寡核苷酸的方法,特异性敲降smad2/3基因的表达,至胚胎发育至6体节,利用整胚原位杂交检测神经嵴细胞特异性标记基因snail1b,sox10,foxd3和crestin的表达情况;通过casmad2 mRNA和smad3a mRNA显微注射的方法过表达smad2和smad3a,同样利用整胚原位杂交检测神经嵴细胞特异性标记基因crestin的表达情况;通过过表达casmad2及smad3a对下调smad2和smad3a的胚胎进行挽救。结果 smad2/3a被敲低后,crestin的表达量显著降低,而snail1b,sox10和foxd3的表达量无明显变化。smad3b被敲低后,crestin,snail1b,sox10和foxd3的表达量均无明显变化;过表达casmad2和smad3a均可导致crestin的表达量增高;过表达casmad2和smad3a可挽救由于smad2/3a敲降所造成crestin的低表达量。结论 Smad2和Smad3a对神经嵴细胞标记基因crestin的表达具有重要作用。     

Physiological response of riparian plants to watering in hyper-arid areas of Tarim River, China

The physiological responses and adaptive strategies of Populus euphratica Oliv. (arbor species), Tamarix ramosissima Ldb. (bush species), and Apocynum venetum L. (herb species) to variations in water and salinity stress were studied in the hyper-arid environment of the Tarim River in China. The groundwater table, the saline content of the groundwater, as well as the content of free proline, soluble sugars, plant endogenous hormones (abscisic acid (ABA), and cytokinins (CTK)) of the leaves of the three species were monitored and analyzed at the lower reaches of the Tarim River in the study area where five transects were fixed at 100 m intervals along a vertical sampling line before and after water release. Saline stress dramatically increased soluble sugar concentration of the three species. Differences in sugar accumulation were determined among the species at different transects. The free proline concentration of the leaves of T. ramosissima and P. euphratica showed a proportional decrease with various degrees of elevation of the groundwater table after water release. There was a least correlation between the soluble sugars and proline stimulation in T. ramosissima. It was strongly suggested that T. ramosissima developed a different strategy to accumulate organic solutes to adapt to the stress environment. The soluble sugars and proline accumulation responded to the changes of groundwater table independently: the former occurred under salt stress, whereas the latter was more significant under drought stress. The concentration and the increase in concentration of ABA and CTK involved in stress resistance of the three species were also determined. This increase in the hormone concentration in P. euphratica was different from that of the other two species. Expressed as a function of increase of ABA concentration in leaves, A. venetum and T. ramosissima showed a different solute accumulation in response to groundwater table. There was a significant correlation between ABA accumulation and Δ [proline] in A. venetum as well as between ABA accumulation and Δ [sugar] in T. ramosissima. Translated from Acta Ecologica Sinica, 2005, 25(8): 1966–1973 [译自: 生态学报]     

A fundamental regulatory role of formate on thuringiensin production by resting cell of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> YBT-032

In this work, a fundamental regulatory role of formate on thuringiensin production by resting cell of Bacillus thuringiensis YBT-032 was investigated. Nicotinamide adenine dinucleotide (NADH) production and formate dehydrogenase activity increased with formate addition from 0.5 to 2.0 g/L, respectively. However, with the formate addition of 1.5 g/L, the activities of pyruvate kinase and glucose 6-phosphate dehydrogenase reached a peak and increased by 316 and 150% relative to those of the control, respectively. In addition, intracellular production of pyruvate, aspartate, citrate and adenine were significantly enhanced by 75, 66, 32 and 78% as well. An improvement (90%) of thuringiensin production was also successfully obtained. Interestingly to point out, thuringiensin yield was closely correlative with adenine production, and the linear relationship was also observed. The results suggest that appropriate formate addition did act as a modulator and facilitate carbon flux in glycolysis and pentose phosphate pathway to synthesize adenine and thuringiensin via intracellular NADH availability.     

The YCR079w gene confers a rapamycin-resistant function and encodes the sixth type 2C protein phosphatase in Saccharomyces cerevisiae

Type 2C protein phosphatase (PP2C) is a monomeric enzyme and requires Mg(2+) or Mn(2+) for its activity. Up to now, seven PP2C-like genes have been identified in the genome of Saccharomyces cerevisiae. However, the protein encoded by the sixth PP2C-like gene, YCR079w, has not been demonstrated to have PP2C activity. In this study, we show that YCR079w confers a rapamycin-resistant function in yeast cells, and we also demonstrate that the YCR079w-encoded protein exhibits characteristics of a typical PP2C. Therefore, YCR079w encodes the sixth PP2C, PTC6, in budding yeast.     

Quercetin relieved diabetic neuropathic pain by inhibiting upregulated P2X4 receptor in dorsal root ganglia

The upregulation of nociceptive ion channels expressed in dorsal root ganglia (DRG) contributes to the development and retaining of diabetic pain symptoms. The flavonoid quercetin (3,3′,4′,5,7-pentahydroxyflavone) is a component extracted from various fruits and vegetables and exerts anti-inflammatory, analgesic, anticarcinogenic, antiulcer, and antihypertensive effects. However, the exact mechanism underlying quercetin's analgesic action remains poorly understood. The aim of this study was to investigate the effects of quercetin on diabetic neuropathic pain related to the P2X₄ receptor in the DRG of type 2 diabetic rat model. Our data showed that both mechanical withdrawal threshold and thermal withdrawal latency in diabetic rats treated with quercetin were higher compared with those in untreated diabetic rats. The expression levels of P2X₄ messenger RNA and protein in the DRG of diabetic rats were increased compared with the control rats, while quercetin treatment significantly inhibited such enhanced P2X₄ expression in diabetic rats. The satellite glial cells (SGCs) enwrap the neuronal soma in the DRG. Quercetin treatment also lowered the elevated coexpression of P2X₄ and glial fibrillary acidic protein (a marker of SGCs) and decreased the upregulation of phosphorylated p38 mitogen-activated protein kinase (p38MAPK) in the DRG of diabetic rats. Quercetin significantly reduced the P2X₄ agonist adenosine triphosphate-activated currents in HEK293 cells transfected with P2X₄ receptors. Thus, our data demonstrate that quercetin may decrease the upregulation of the P2X₄ receptor in DRG SGCs, and consequently inhibit P2X₄ receptor-mediated p38MAPK activation to relieve the mechanical and thermal hyperalgesia in diabetic rats.     

Long noncoding RNA OIP5-AS1 acts as a competing endogenous RNA to promote glutamine catabolism and malignant melanoma growth by sponging miR-217

The long noncoding RNA (lncRNA) OIP5-AS1 has been considered to promote the growth and metastasis of many human tumors. However, the role of OIP5-AS1 in melanoma has not been reported. In this study, we found that OIP5-AS1 levels were significantly elevated in melanoma tissue and that high OIP5-AS1 expression was an independent risk factor for the poor survival of patients with melanoma. miR-217 suppressed glutamine catabolism in melanoma cells by targeting glutaminase (GLS), the rate-limiting enzyme of glutamine catabolism. We also demonstrated that OIP5-AS1 acted as a sponge of miR-217 to upregulate GLS expression, thus promoting glutamine catabolism and melanoma growth. Overall, this result elucidates a new mechanism for OIP5-AS1 in metabolism in melanoma and provides a potential therapeutic target for patients with melanoma.     

C1q/tumor necrosis factor-related protein-3 improves renal fibrosis via inhibiting notch signaling pathways

C1q/tumor necrosis factor-related protein-3 (CTRP3) has been extensively reported as an important role involved in antifibrosis, antiapoptosis, and anti-inflammation. However, the role of CTRP3 involved in renal fibrosis remains unclear. Our current study explored the role of CTRP3 in renal fibrosis and its underlying mechanisms by using serums and renal biopsy specimens from renal fibrosis patients and control subjects, rats models with the surgery of unilateral ureteral obstruction (UUO) and human renal proximal tubular epithelial cells (HRPTEpiCs). We found that circulating levels of CTRP3 had no significant difference between renal fibrosis patients and healthy subjects; however, renal CTRP3 expression was markedly downregulated in the fibrotic region with an abundant expression of collagen-I. In UUO rat models, circulating levels of CTRP3 have not changed with the prolonged obstruction of the kidney; renal CTRP3 expression was decreased with the severity of renal fibrosis; adenovirus-mediated CTRP3 treatment inhibited renal interstitial fibrosis. In vitro experiments revealed that CTRP3 attenuates TGF-β1 induced tubular epithelial cells fibrotic changes; CTRP3 knockdown facilitates the expression of fibrotic markers in TGF-β1-induced HRPTEpiCs; recombinant CTRP3 or adenovirus-mediated CTRP3 overexpression significantly inhibited the Notch signaling pathway-associated factors, and knockdown of CTRP3 increased TGF-β1-mediated activation of the Notch signaling pathways. Collectively, our current study found that CTRP3 could improve renal fibrosis, to some extent, through inhibiting the Notch pathway.     

花生根瘤菌Bradyrhizobium sp.MZ5 III型分泌系统调节基因ttsI突变体的功能分析

[目的]探究慢生型花生根瘤菌III型分泌系统在花生-根瘤菌互作的功能。[方法]本研究采用同源重组和三亲本接合转移的方法,构建Bradyrhizobium sp.MZ5的III型分泌系统调节基因ttsI突变体;荧光定量PCR检测添加大豆苷元（Daidzein）和染料木黄酮（Genistein）诱导物后野生型和突变株转录水平上ttsI的表达量变化及其差异;蛭石结瘤实验分析ttsI基因突变对花生结瘤能力的影响。[结果]在转录水平上,大豆苷元和染料木黄酮对MZ5的III型分泌系统调节基因ttsI的表达具有显著的抑制作用（P<0.05）。在MZ5△ttsI突变体中ttsI基因的表达量都明显下调,与野生型菌株的相比都达到极显著水平（P<0.001）。蛭石结瘤实验表明,与野生型菌株相比,MZ5△ttsI突变体在不同花生品种的结瘤数和地上部干重都显著性降低。根瘤石蜡切片表明,MZ5△ttsI突变体在根瘤内的含菌量少于野生型菌株。[结论]Bradyrhizobium sp.MZ5菌株中的III型分泌系统在花生-根瘤菌互作中对结瘤有积极的促进作用。     

Role of caveolin-1 in epidermal stem cells during burn wound healing in rats

Local transplantation of stem cells has therapeutic effects on skin damage but cannot provide satisfactory wound healing. Studies on the mechanisms underlying the therapeutic effects of stem cells on skin wound healing will be needed. Hence, in the present study, we explored the role of Caveolin-1 in epidermal stem cells (EpiSCs) in the modulation of wound healing. We first isolated EpiSCs from mouse skin tissues and established stable EpiSCs with overexpression of Caveolin-1 using a lentiviral construct. We then evaluated the epidermal growth factor (EGF)-induced cell proliferation ability using cell counting Kit-8 (CCK-8) assay and assessed EpiSC pluripotency by examining Nanog mRNA levels in EpiSCs. Furthermore, we treated mice with skin burn injury using EpiSCs with overexpression of Caveolin-1. Histological examinations were conducted to evaluate re-epithelialization, wound scores, cell proliferation and capillary density in wounds. We found that overexpression of Caveolin-1 in EpiSCs promoted EGF-induced cell proliferation ability and increased wound closure in a mouse model of skin burn injury. Histological evaluation demonstrated that overexpression of Caveolin-1 in EpiSCs promoted re-epithelialization in wounds, enhanced cellularity, and increased vasculature, as well as increased wound scores. Taken together, our results suggested that Caveolin-1 expression in the EpiSCs play a critical role in the regulation of EpiSC proliferation ability and alteration of EpiSC proliferation ability may be an effective approach in promoting EpiSC-based therapy in skin wound healing.