松油烯-4-醇对粘虫的致毒机制

采用华氏呼吸仪法、常规生化酶活力测定等方法,测定松油烯-4-醇熏蒸处理对粘虫Mythimna separata(Walker)幼虫呼吸作用、血淋巴理化性状、体内酶系活性等的影响。结果表明,松油烯-4-醇显著地影响粘虫的呼吸作用,不同中毒阶段试虫的呼吸率均显著提高,呼吸商发生改变;血淋巴理化性状也发生一定程度的变化,血淋巴总量随中毒程度的加深呈下降趋势,兴奋期、痉挛期、昏迷期血淋巴总量分别为对照试虫的85.55%、70.39%、38.47%,血淋巴比重呈上升趋势,pH值和渗透压变化不大;体内Na+-K+-ATP酶的活性受到明显抑制,头部组织中Na+-K+-ATP酶活性的抑制率在兴奋期、痉挛期分别达36.4%、80.2%,中肠组织中Na+-K+-ATP酶活性的抑制率达50%左右,对乙酰胆碱脂酶活性影响不大,对酯酶则是先激活后抑制。松油烯-4-醇对Na+-K+-ATP酶活性的抑制可能与粘虫最终死亡有关。     

Impacts of population growth and economic development on the nitrogen cycle in Asia

Asia is the major consumer of fertilizer nitrogen and energy in the world, and consequently shares a considerable proportion of the world creation of reactive nitrogen (Nr). However, if estimated on per capita basis, Asia is characterized by a lower arable land area, fertilizer nitrogen consumption, energy consumption, and gross domestic product, as well as lower daily protein intake. To meet the increasing needs for food and energy for the growing population combined with the improvement of living standards, Nr will inevitably increase. The present study estimates the creation of Nr and the emissions of various N compounds into environment in Asia currently and in 2030. In comparison with the world averages, the lower fertilizer nitrogen and energy use efficiencies, and the lower use of animal wastes for agriculture imply that there is potential for moderating the increase in Nr and its impacts on the environment. Strategies for moderating the increase are discussed.     

外源α-萘乙酸对花期干旱大豆碳代谢的影响

以耐旱性大豆品种晋豆21和干旱敏感性大豆品种徐豆22为试验材料,通过盆栽试验,研究α-萘乙酸(NAA)对花期干旱大豆碳代谢的影响.结果表明: 干旱胁迫下,与徐豆22相比,晋豆21净光合速率(P_n)下降幅度较小,光呼吸速率(P_r)和叶片可溶性糖含量增加幅度较小,而叶片蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)(合成方向)活性、根系蔗糖含量增加幅度较大.NAA处理提高了干旱胁迫下P_n,并降低了P_r,进而明显缓解了干旱胁迫对大豆植株的生长抑制;降低了叶片淀粉分解酶、酸性转化酶(AI)和SS(分解方向)活性,从而抑制了干旱胁迫诱导的可溶性糖积累;NAA处理也能增加干旱胁迫下叶片SPS、SS(合成方向)活性、根系蔗糖含量、根冠比,表明NAA处理促进了叶片中蔗糖向根系的转运.总之,在干旱胁迫下,外源NAA能够通过调控碳代谢增强大豆植株对干旱胁迫的耐受性.     

Species turnover in ant assemblages is greater horizontally than vertically in the world's tallest tropical forest

Abiotic and biotic factors structure species assembly in ecosystems both horizontally and vertically. However, the way community composition changes along comparable horizontal and vertical distances in complex three‐dimensional habitats, and the factors driving these patterns, remains poorly understood. By sampling ant assemblages at comparable vertical and horizontal spatial scales in a tropical rainforest, we tested hypotheses that predicted differences in vertical and horizontal turnover explained by different drivers in vertical and horizontal space. These drivers included environmental filtering, such as microclimate (temperature, humidity, and photosynthetic photon flux density) and microhabitat connectivity (leaf area), which are structured differently across vertical and horizontal space. We found that both ant abundance and richness decreased significantly with increasing vertical height. Although the dissimilarity between ant assemblages increased with vertical distance, indicating a clear distance‐decay pattern, the dissimilarity was higher horizontally where it appeared independent of distance. The pronounced horizontal and vertical structuring of ant assemblages across short distances is likely explained by a combination of microclimate and microhabitat connectivity. Our results demonstrate the importance of considering three‐dimensional spatial variation in local assemblages and reveal how highly diverse communities can be supported by complex habitats.     

Ginsenoside Rd Attenuates Myocardial Ischemia/Reperfusion Injury via Akt/GSK-3β Signaling and Inhibition of the Mitochondria-Dependent Apoptotic Pathway

Evidence suggests Ginsenoside Rd (GSRd), a biologically active extract from the medical plant Panax Ginseng, exerts antioxidant effect, decreasing reactive oxygen species (ROS) formation. Current study determined the effect of GSRd on myocardial ischemia/reperfusion (MI/R) injury (a pathological condition where ROS production is significantly increased) and investigated the underlying mechanisms. The current study utilized an in vivo rat model of MI/R injury and an in vitro neonatal rat cardiomyocyte (NRC) model of simulated ischemia/reperfusion (SI/R) injury. Infarct size was measured by Evans blue/TTC double staining. NRC injury was determined by MTT and lactate dehydrogenase (LDH) leakage assay. ROS accumulation and apoptosis were assessed by flow cytometry. Mitochondrial membrane potential (MMP) was determined by 5, 5′, 6, 6′-tetrachloro-1, 1′, 3, 3′-tetrathylbenzimidazol carbocyanine iodide (JC-1). Cytosolic translocation of mitochondrial cytochrome c and expression of caspase-9, caspase-3, Bcl-2 family proteins, and phosphorylated Akt and GSK-3β were determined by western blot. Pretreatment with GSRd (50 mg/kg) significantly augmented rat cardiac function, as evidenced by increased left ventricular ejection fraction (LVEF) and ±dP/dt. GSRd reduced myocardial infarct size, apoptotic cell death, and blood creatine kinase/lactate dehydrogenase levels after MI/R. In NRCs, GSRd (10 µM) inhibited SI/R-induced ROS generation (P<0.01), decreased cellular apoptosis, stabilized the mitochondrial membrane potential (MMP), and attenuated cytosolic translocation of mitochondrial cytochrome c. GSRd inhibited activation of caspase-9 and caspase-3, increased the phosphorylated Akt and GSK-3β, and increased the Bcl-2/Bax ratio. Together, these data demonstrate GSRd mediated cardioprotective effect against MI/R–induced apoptosis via a mitochondrial-dependent apoptotic pathway.     

The Ras GTPase-activating-like protein IQGAP1 is downregulated in human diabetic nephropathy and associated with ERK1/2 pathway activation

Podocyte injury may contribute to the pathogenesis of diabetic nephropathy (DN), but the underlying mechanism of hyperglycemia induced podocyte damage is not fully understood. The Ras GTPase-activating-like protein IQGAP1 is associated to the slit diaphragm proteins and the actin cytoskeleton in podocyte. Here, we studied IQGAP1 expression alterations in human DN biopsies and extracellular signal-regulated kinase (ERK)-dependent pathways of IQGAP1 expression in podocyte under high glucose (HG) media. In vivo, analysis of renal biopsies from patients with DN revealed a significant reduction in IQGAP1 expression compared to controls. In vitro, IQGAP1 mRNA and protein expression were observed to decline under HG media at 48 h. But phosphorylation of ERK1/2 was activated under HG media at 24 h and 48 h. However, HG-induced downregulation of IQGAP1 protein was attenuated by specific ERK1/2 activation inhibitor PD98059. Taken together, these results highlight the importance of IQGAP1 in DN, and suggest that IQGAP1 expression in podocyte under HG media is modulated by the ERK1/2 pathway, which may lead to the future development of therapies targeting IQGAP1 dysfunction in podocytes in DN.     

Screening and characterization of astaxanthin-hyperproducing mutants of Haematococcus pluvialis

Haematococcus pluvialis was mutated by UV or ethyl methanesulphonate. Mutants resistant to nicotine, diphenylamine, fluridone or norflurazon were then selected. Several nicotine-resistant mutants showed increased (1.9% to 2.5% vs. 1.2% w/w) astaxanthin production. Mutants maintained high astaxanthin production over 4 months of repeated culture.     

C.elegans野生型和par突变体早期胚胎卵裂的观察

不对称分裂在动植物的发育中起到了非常重要的作用。Caenorhabditis elegans（C．elegans）胚胎最早的两次卵裂为研究控制不对称分裂的机制提供了很好的机会。用普通光学显微镜观察了野生型胚胎早期卵裂和par-1、par-2、par-3、par-4突变体胚胎的早期卵裂。野生型胚胎最早的分裂是不等的,产生了两个不同大小的子细胞。两个子细胞又以不同的方向进行第二次分裂。在C．elegans中任意一个par基因的缺失会使胚胎的第一次卵裂丧失不对称性。这会导致一些发育调控因子不能在特定的胚胎细胞中准确地定位,造成细胞分裂纺锤体方向的异常。par类基因参与不对称性的建立,这种不对称性决定了C．elegans身体的前后轴。     

Enzyme-assisted extraction of flavonoids from Ginkgo biloba leaves: improvement effect of flavonol transglycosylation catalyzed by Penicillium decumbens cellulase

We report a novel enzyme-involved approach to improve the extraction of flavonoids from Ginkgo biloba, in which the enzyme is employed not only for cell wall degradation, but also for increasing the solubility of target compounds in the ethanol-water extractant. Penicillium decumbens cellulase, a commercial cell wall-degrading enzyme with high transglycosylation activity, was found to offer far better performance in the extraction than Trichoderma reesei cellulase and Aspergillus niger pectinase under the presence of maltose as the glycosyl donor. TLC, HPLC and MS analysis indicated that P. decumbens cellulase could transglycosylate flavonol aglycones into more polar glucosides, the higher solubility of which led to improved extraction. The influence of glycosyl donor, pH, solvent and temperature on the enzymatic transglycosylation was investigated. For three predominant flavonoids in G. biloba, the transglycosylation showed similar optimal conditions, which were therefore used for the enzyme-assisted extraction. The extraction yield turned to be 28.3mg/g of dw, 31% higher than that under the pre-optimized conditions, and 102% higher than that under the conditions without enzymes. The utilization of enzymatic bifunctionality described here, naming enzymatic modification of target compounds and facilitation of cell wall degradation, provides a novel approach for the extraction of natural compounds from plants.