Genetic, proteomic and metabolic analysis of the regulation of energy storage in rice seedlings in response to drought

We used proteomic analysis to determine the response of rice plant seedlings to drought-induced stress. The expression of 71 protein spots was significantly altered, and 60 spots were successfully identified. The greatest down-regulated protein functional category was translation. Up-regulated proteins were mainly related to protein folding and assembly. Additionally, many proteins involved in metabolism (e.g. carbohydrate metabolism) also showed differences in expression. cDNA microarray and GC-MS analysis showed 4756 differentially expressed mRNAs and 37 differentially expressed metabolites. Once these data were integrated with the proteomic analysis, we were able to elucidate the metabolic pathways affected by drought-induced stress. These results suggest that increased energy consumption from storage substances occurred during drought. In addition, increased expression of the enzymes involved in anabolic pathways corresponded with an increase in the content of six amino acids. We speculated that energy conversion from carbohydrates and/or fatty acids to amino acids was increased. Analysis of basic metabolism networks allowed us to understand how rice plants adjust to drought conditions.     

Blockade of human group X secreted phospholipase A2 (GX-sPLA2)-induced airway inflammation and hyperresponsiveness in a mouse asthma model by a selective GX-sPLA2 inhibitor

Group X (GX) phospholipase A(2), a member of a large group of secreted phospholipases A(2) (sPLA(2)s), has recently been demonstrated to play an important in vivo role in the release of arachidonic acid and subsequent formation of eicosanoids. In a Th2 cytokine-driven mouse asthma model, deficiency of mouse GX (mGX)-sPLA(2) significantly impairs development of the asthma phenotype. In this study, we generated mGX-sPLA(2)(-/-) mice with knock-in of human GX (hGX)-sPLA(2) (i.e. hGX-sPLA(2)(+/+) knock-in mice) to understand more fully the role of GX-sPLA(2) in these allergic pulmonary responses and to assess the effect of pharmacological blockade of the GX-sPLA(2)-mediated responses. Knock-in of hGX-sPLA(2) in mGX-sPLA(2)(-/-) mice restored the allergen-induced airway infiltration by inflammatory cells, including eosinophils, goblet cell metaplasia, and hyperresponsiveness to methacholine in the mGX-sPLA(2)-deficient mice. This knock-in mouse model enabled the use of a highly potent indole-based inhibitor of hGX-sPLA(2), RO061606 (which is ineffective against mGX-sPLA(2)), to assess the potential utility of GX-sPLA(2) blockade as a therapeutic intervention in asthma. Delivery of RO061606 via mini-osmotic pumps enabled the maintenance in vivo in the mouse asthma model of plasma inhibitor concentrations near 10 μm, markedly higher than the IC(50) for inhibition of hGX-sPLA(2) in vitro. RO061606 significantly decreased allergen-induced airway inflammation, mucus hypersecretion, and hyperresponsiveness in the hGX-sPLA(2)(+/+) knock-in mouse. Thus, development of specific hGX-sPLA(2) inhibitors may provide a new pharmacological opportunity for the treatment of patients with asthma.     

HIV Vaccine-Challenges and Opportunities

The need for an efficacious HIV/AIDS vaccine remains the highest priority of the world HIV/AIDS agenda. The generation of an efficacious HIV/AIDS vaccine proves an enormous scientific challenge. This article reviews the neutralizing antibody problem,elusive immune protection,im-munogen design,pre-existing anti-vector immunity and design of phase 3 vaccine trials and the challenges and opportunities in development of HIV/AIDS vaccine are discussed.     

Synthesis, characterization, and in vivo biodistribution of 125I-labeled Dex-g-PMAGGCONHTyr

Dextran graft poly (N-methacryloylglycylglycine) copolymer-tyrosine conjugates (dextran-g-PMAGGCONHTyr) were synthesized and characterized. Dynamic light scattering (DLS) results indicated that the graft copolymers are soluble in pH 7.4 PBS and 0.9% saline solutions. The graft copolymers were labeled with (125)I, and the labeling stability in 0.9% saline solution was investigated. Pharmacokinetics studies showed a rapid clearance of (125)I-labeled graft copolymers from the blood pool. Biodistribution images confirmed the preferable liver and spleen accumulation within 1 h after injection and rapid clearance from all the organs over time. The graft copolymer with molecular weight of 9.8 kDa was eliminated from the kidney significantly faster than those with higher molecular weight. The effect of the numbers of -COOH groups on the graft copolymers on the biodistribution was also investigated. It was found that the graft copolymers with the average number of -COOH groups per glucopyranose unit (DS(-COOH)) of 0.57 and 0.18 are mainly distributed in liver and spleen at 1 h after injection, whereas the graft copolymer with DS(-COOH) of 0.07 is mainly accumulated in kidney.     

Prolyl hydroxylase domain protein 3 targets Pax2 for destruction

Rhomboid-7 (rho-7) is a mitochondrial-specific intramembranous protease. The loss-of-function mutation rho-7 results in semi-lethality, while escapers have a reduced lifespan with several neurological disorders [1]. Here we show that general, or CNS-specific expression of rho-7 can rescue the lethality of rho-7. General, or CNS-specific over-expression of rho-7 in otherwise wild-type animals caused semi-lethality, with approximately 50% of the animals escaping this lethality, developing into adults displaying a shortened life span with larval locomotory problem. On a cellular level, over-expression resulted in severe depression of ATP levels and cytochrome c oxidase subunit II mRNA levels, a lowered number of mitochondria in neurons and aggregation of mitochondria in the brain indicating mitochondrial malfunction. Over-expression of rho-7 in developing eye discs resulted in an elevated apoptotic index. In the CNS, elevated levels of rho-7 were accompanied by both isoforms of Opa1-like, a dynamin-like GTPase, a mitochondrial component involved in regulating mitochondrial dynamics and function, including apoptosis. Most, but not all, of rho-7 over-expression phenotypes were suppressed by introducing a heterozygous mutation for Opa1-like. Our results suggest that rho-7 and Opa1-like function in a common molecular pathway affecting mitochondrial function and apoptosis in Drosophila melanogaster.     

乙醇对大鼠心肌动作电位及人Kv1.5通道的影响

为了研究乙醇对心肌动作电位的作用及其机制,本实验采用标准玻璃微电极细胞内记录技术记录离体大鼠心肌细胞的动作电位(action potential,AP),采用全细胞膜片钳技术记录HEK293细胞上表达的人Kv1.5(human Kv1.5,hKv1.5)通道电流,观察6.25、12.5、25.0、50.0、100.0及...     

Diversity and Biogeography of Rhizobia Isolated from Root Nodules of <Emphasis Type="Italic">Glycine max</Emphasis> Grown in Hebei Province,China

A total of 215 rhizobial strains were isolated and analyzed with 16S rRNA gene, 16S–23S intergenic spacer, housekeeping genes atpD, recA, and glnII, and symbiotic genes nifH and nodC to understand the genetic diversity of soybean rhizobia in Hebei province, China. All the strains except one were symbiotic bacteria classified into nine genospecies in the genera of Bradyrhizobium and Sinorhizobium. Surveys on the distribution of these rhizobia in different regions showed that Bradyrhizobium japonicum and Bradyrhizobium elkanii strains were found only in neutral to slightly alkaline soils whereas Bradyrhizobium yuanmingense, Bradyrhizobium liaoningense-related strains and strains of five Sinorhizobium genospecies were found in alkaline–saline soils. Correspondence and canonical correspondence analyses on the relationship of rhizobial distribution and their soil characteristics reveal that high soil pH, electrical conductivity, and potassium content favor distribution of the B. yuanmingense and the five Sinorhizobium species but inhibit B. japonicum and B. elkanii. High contents of available phosphorus and organic matters benefit Sinorhizobium fredii and B. liaoningense-related strains and inhibit the others groups mentioned above. The symbiotic gene (nifH and nodC) lineages among B. elkanii, B. japonicum, B. yuanmingense, and Sinorhizobium spp. were observed in the strains, signifying that vertical gene transfer was the main mechanism to maintain these genes in the soybean rhizobia. However, lateral transfer of symbiotic genes commonly in Sinorhizobium spp. and rarely in Bradyrhizobium spp. was also detected. These results showed the genetic diversity, the biogeography, and the soil determinant factors of soybean rhizobia in Hebei province of China.     

Evidence for a role of C-terminus in Ca(2+) inactivation of skeletal muscle Ca(2+) release channel (ryanodine receptor).

Six chimeras of the skeletal muscle (RyR1) and cardiac muscle (RyR2) Ca(2+) release channels (ryanodine receptors) previously used to identify RyR1 dihydropyridine receptor interactions [Nakai et al. (1998) J. Biol. Chem. 273, 13403] were expressed in HEK293 cells to assess their Ca(2+) dependence in [(3)H]ryanodine binding and single channel measurements. The results indicate that the C-terminal one-fourth has a major role in Ca(2+) activation and inactivation of RyR1. Further, our results show that replacement of RyR1 regions with corresponding RyR2 regions can result in loss and/or reduction of [(3)H]ryanodine binding affinity while maintaining channel activity.     

城市公园绿地水、热与CO2通量观测与分析

水、热和CO2通量是评价城市绿地生态效益的重要指标。在北京海淀公园中部和边缘架设涡度相关系统,连续观测和定量研究城市公园绿地影响下的通量变化特征。结果表明,公园绿地所获得的净辐射在植被生长季节大部分用于植被的蒸散作用,潜热大于显热;而在植被非生长季节大部分用于显热,潜热数值非常小。晴天显热与潜热的比值在春季随着植被枝叶的生长逐渐减少,到夏季达到最小值约1/3,在秋季随着植被叶片枯黄逐渐变大,冬季达到数倍。公园绿地能量平衡率在52%～83%,普遍存在能量不平衡。公园中部的潜热观测值大于公园边缘,而显热小于公园边缘;公园中部CO2通量日均值为负,公园绿地是CO2汇。公园绿地在植被生长季节具有明显的降温增湿、吸收CO2等生态效应。