Effect of NaCl stress on rice physiological properties

Salinity is a major yield-reducing factor in coastal and arid irrigated rice production systems. Rice seedlings (Oryza sativa cv. Tarom Atri) were exposed to different NaCl concentrations for 8 days after germination. Plants height, fresh and dry weight, relative water content, pigment and carbohydrate content, photosynthetic efficiency and lipid peroxidase and antioxidant enzyme activity of rice seedlings grown under salt stress were investigated. Seedling grown under 25and 50 mM salt were shorter than the control. They could, however, develop their secondary leaves. Seedlings grown in the nutrient solution supplied with 100 and 200 mM extra salt could not develop their secondary leaves. Fresh weight ofseedlings grown under salt stress reduced up to 42.2% of the non-treated seedlings. Chlorophylls and carotenoids contents decreased significantly in the salt-treated seedlings. Carotenoid contents in NaCl-treated seedlings were decreased to 39.3%. No significant changes occurred in the photochemical efficiency of control and stressed plants. Increasing concentrations of NaCl resulted in increase and decrease of Na⁺ and K⁺ ions, respectively. NaCl salinity caused an increase in both peroxide content and lipid peroxidation. Seedlings which recovered for 24 h showed lower peroxide and malondialdehyde content.     

Synthesis and evaluation of a 125I-labeled iminodihydroquinoline-derived tracer for imaging of voltage-gated sodium channels

In vivo imaging of voltage-gated sodium channels (VGSCs) can potentially provide insights into the activation of neuronal pathways and aid the diagnosis of a number of neurological diseases. The iminodihydroquinoline WIN17317-3 is one of the most potent sodium channel blockers reported to date and binds with high affinity to VGSCs throughout the rat brain. We have synthesized a ¹²⁵I-labeled analogue of WIN17317-3 and evaluated the potential of the tracer for imaging of VGSCs with SPECT. Automated patch clamp studies with CHO cells expressing the Na_v1.2 isoform and displacement studies with [³H]BTX yielded comparable results for the non-radioactive iodinated iminodihydroquinoline and WIN17317-3. However, the ¹²⁵I-labeled tracer was rapidly metabolized in vivo, and suffered from low brain uptake and high accumulation of radioactivity in the intestines. The results suggest that iminodihydroquinolines are poorly suited for tracer development.     

盐胁迫对二穗短柄草幼苗生长及不同器官中盐离子稳态的影响

采用4种浓度的NaCl溶液(50、100、150、200 mmol/L)处理二穗短柄草和拟南芥(对照)幼苗,测定不同浓度盐胁迫下2种植物幼苗的生长指标和离子分布,以探讨二穗短柄草在盐胁迫下主要阳离子平衡机制.结果表明:(1)盐胁迫显著抑制二穗短柄草根叶的生物量积累.(2)根冠比数据显示,在盐胁迫条件下二穗短柄草能够更好地维系地下部分的生物量积累.(3)在4种浓度盐胁迫下,二穗短柄草叶中Na+含量低于根系,而且K+、Cl-含量和K+/Na+比值始终高于根系,说明在二穗短柄草中Na+从地下到地上的转运受到抑制,但对Cl-的转运缺乏有效的调控.(4)回归分析发现,盐胁迫下二穗短柄草和拟南芥根部Na+与K+含量变化呈正相关关系,而在叶部则不相关,说明二穗短柄草和拟南芥Na+与K+在根部具有相同的离子通道,而在叶部却具有各自独立的转运途径.     

Optimization of Exopolysaccharide Overproduction by Lactobacillus confusus in Solid State Fermentation under High Salinity Stress

It is believed that high concentrations of sodium chloride (NaCl) suppress the biosynthesis of exopolysaccharide (EPS) in lactic acid bacteria (LAB). Nevertheless, overproduction of EPSs due to high salinity stress in solid state fermentation performed on an agar surface was demonstrated in this study using a response surface methodology via a central composite design (CCD). Under optimized conditions with NaCl 4.97% and sucrose 136.5 g/L at 40.79 h of incubation, the EPS yield was 259% (86.36 g/L of EPS), higher than the maximum yield produced with the modified MRS medium containing only 120 g/L of sucrose without NaCl (33.4 g/L of EPS). Biosynthesis of EPS by Lactobacillus confusus TISTR 1498 was independent of biomass production. Our results indicated that high salinity stress can enhance EPS production in solid state fermentation.     

Nucleostemin基因在卵巢上皮性肿瘤的表达及与病理分型的关系

目的：研究核干细胞因子Nucleostemin（NS）基因在卵巢上皮性肿瘤中的表达,探讨其与肿瘤病理分型的关系。方法：采用RT-PCR及Western blot检测36例卵巢癌组织手术标本,32例卵巢良性上皮肿瘤组织手术标本,12例正常卵巢组织标本中Nu-cleostemin基因及相应蛋白的表达,采用分组对照的方法对比3组样本中NS基因及蛋白的表达情况,并进行相对定量研究。采用统计学方法检测NS基因的表达是否与临床病理分级及血清CA125存在关联。结果：①卵巢癌组织中NS的阳性表达率显著高于良性肿瘤组织及正常卵巢组织;②卵巢癌组织中,淋巴结转移组NS的表达水平高于未转移组;③临床分期Ⅲ期组的表达水平高于ⅠB期组;④中、低分化组的表达水平高于高分化组。结论：卵巢癌组织中存在NS基因的高表达,其表达量与组织类型无关,而与临床TNM分期及组织分级正相关。     

Melanin is crucial for growth of the black yeast Hortaea werneckii in its natural hypersaline environment

Melanin has an important role in the ability of fungi to survive extreme conditions, like the high NaCl concentrations that are typical of hypersaline environments. The black fungus Hortaea werneckii that has been isolated from such environments has 1,8-dihydroxynaphthalene-melanin incorporated into the cell wall, which minimises the loss of glycerol at low NaCl concentrations. To further explore the role of melanin in the extremely halotolerant character of H. werneckii, we studied the effects of several melanin biosynthesis inhibitors on its growth, pigmentation and cell morphology. The most potent inhibitors were a 2,3-dihydrobenzofuran derivative and tricyclazole, which restricted the growth of H. werneckii on high-salinity media, as shown by growth curves and plate-drop assays. These inhibitors promoted release of the pigments from the H. werneckii cell surface and changed the medium colour. Inhibitor-treated H. werneckii cells exposed to high salinity showed both decreased and increased cell lengths. We speculate that this absence of melanin perturbs the integrity of the cell wall in H. werneckii, which affects its cell division and exposes it to the harmful effects of high NaCl concentrations. Surprisingly, melanin had no effect on H. werneckii survival under H₂O₂ oxidative stress.     

地高辛对老年慢性心衰患者血清CA125，BNP及MMP-9 水平的影响

目的:探讨地高辛片对老年慢性心力衰竭患者血清血清糖类抗原(CA125)、心钠肽(ANP)、脑钠肽(BNP)、基质金属蛋白酶9(MMP-9)及金属蛋白酶组织抑制剂(TIMP-1)水平的影响。方法:收集我院老年慢性心力衰竭患者100例,随机分为对照组和实验组,每组各50例,对照组患者给予常规治疗,实验组患者在对照组的基础上给予地高辛片。比较治疗前后两组患者血清糖类抗原(CA125)、心钠肽(ANP)、脑钠肽(BNP)、基质金属蛋白酶9(MMP-9)及金属蛋白酶组织抑制剂(TIMP-1)水平。结果:与治疗前相比,两组患者血清CA125、ANP、BNP及MMP-9水平降低,TIMP-1水平升高(P0.05);治疗后与对照组相比,实验组CA125水平(34.05±4.63)较低,ANP水平较低(216.98±27.65),BNP水平较低(437.62±45.26),MMP-9水平较低(550.17±65.15),TIMP-1水平较高(182.32±21.78)(P0.05)。结论:地高辛片能够改善老年慢性心力衰竭患者心肌功能,推测其机制可能与降低血清CA125、ANP、BNP、MMP-9水平,升高TIMP-1水平有关。