Isoelectric focusing in immobilized pH gradients of a snake venom fibrinolytic enzyme

A fibrinolytic enzyme with a molecular weight between 23,000 and 25,000 Da has been purified from southern copperhead snake venom. Immobilized pH gradient isoelectric focusing with an ultranarrow pH interval (pH 6.65-6.95) resolved two isoforms of the fibrinolytic enzyme that were not resolved by standard isoelectric focusing. Attempts at purification of the individual isoenzymes by semi-preparative scale IPG and elution of enzyme by macerating the gel yielded only 20-40% recovery of activity. In attempts to improve recovery, a semi-preparative IPG canal-isoelectric focusing technique has been utilized.     

棉铃虫幼虫加单氧酶活性的组织分布

棉铃虫（Ｈｅｌｉｃｏｖｅｒｐａ ａｒｍｉｇｅｒａ）６龄幼虫不同组织的加单氧酶活性的测定结果显示,对－硝基苯甲醚Ｏ－脱甲基酶主要分由于外来物质的入口部位,以中肠和脂肪体的活性较高,在前肠、后肠和马氏管等组织中有相对较低的活性,而在体壁和精巢中未检测到Ｏ－ 甲基作用。体壁表现一定的艾氏剂环氧化作用,但其活性不及中肠的１０％,内源性制剂被证明并非体壁低加单氧酶活性的主要原因。不同组织生物量的差异及其动态     

Dietary supplementation with docosahexaenoic acid,but not with eicosapentaenoic acid,reduces host resistance to fungal infection in mice

The effect of dietary docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on host resistance to Paracoccidioides brasiliensis infection was investigated. Mice fed palm oil supplemented with DHA showed reduced antifungal activity in the spleen and liver, as compared with mice fed palm oil or soybean oil without supplementation with DHA. Mice fed DHA-supplemented soybean oil also showed reduced antifungal activity in the liver, but the extent of reduction was less profound. This reduction in antifungal activity was not observed with EPA-supplemented palm or EPA-supplemented soybean oil. These results suggest that two factors, DHA and palm oil in combination, are involved in reducing the host resistance. DHA-enriched palm oil was also responsible for an increase in DHA concentration and a marked decrease in arachidonic acid content in the spleen and liver. However, this group did not show elevated spleen and liver phospholipid hydroperoxide levels compared with the other groups, excluding the possibility that the reduction in antifungal activity observed with DHA-enriched palm oil is due to acceleration of in vivo lipid peroxidation. Greater infection-induced increases in spleen and serum interferon-gamma concentrations were observed in mice fed DHA-enriched palm oil compared with the other groups.     

The intrinsic mechanisms underlying the maturation of programming sequential spikes at cerebellar Purkinje cells

Cerebellum is involved in the motion coordination and working memory, to which the programming of sequential spikes at Purkinje cells is essential. It is not clear about the intrinsic mechanisms underlying spike capacity and timing precision as well as their postnatal maturation. We investigated the programming and intrinsic property of sequential spikes at Purkinje neurons during postnatal development by whole-cell recording in cerebellar slices. Cerebellar Purkinje neurons demonstrate the increasing of spike capacity and timing precision, as well as the lowering of refractory periods and threshold potentials during the postnatal maturation. In addition, the correlation between spike parameters and intrinsic properties converts to be more linear. This postnatal plasticity of neuronal intrinsic properties improves the timing precision and capacity of spike programming at cerebellar Purkinje neurons.     

Probing the ligand preferences of the three types of bacterial pantothenate kinase

Pantothenate kinase (PanK) catalyzes the transformation of pantothenate to 4′-phosphopantothenate, the first committed step in coenzyme A biosynthesis. While numerous pantothenate antimetabolites and PanK inhibitors have been reported for bacterial type I and type II PanKs, only a few weak inhibitors are known for bacterial type III PanK enzymes. Here, a series of pantothenate analogues were synthesized using convenient synthetic methodology. The compounds were exploited as small organic probes to compare the ligand preferences of the three different types of bacterial PanK. Overall, several new inhibitors and substrates were identified for each type of PanK.     

Modeling and dynamic assessment of urban economy–resource–environment system with a coupled system dynamics – geographic information system model

At present, environmental issues associated with rapid economic development are becoming critical concerns that arouse government's and people's particular attention. A large amount of influencing factors and especially their complicated interactions have always thrown confused insights into assessing the dynamic evolvement and sustainable development of urban economy–resource–environment (ERE) system and programming the developing strategies. A combination of system dynamics (SD) and geographic information system (GIS) is expected to explicitly understand the synergic interaction and feedback among a variety of influencing factors in time and space, since SD model can extend the spatial analysis functions of GIS to realize both dynamic simulation and trend prediction of an ERE system development. According to connotation and framework of sustainable development, this study proposes a dynamic combination method of SD–GIS to model and evaluate the urban development in Chongqing city of China suffering from depletion of resource and degradation of environment. To compare different policy inclinations with regard to potential ERE effects, typical scenarios (current, resource, technology and environment scenarios) are designed by adjusting the parameters in the model and changing the specification of some variables. Integrated assessment results indicate that the current ERE system of Chongqing is not sustainable; environment scenario is more effective to sustainable development of urban ERE system in a long run. Under the considerations of development features and regional differences, as well as regular discipline on urbanization, a coordinated combination of environmental, resource and technology scenarios is anticipated to realize sustainable development of urban ERE system.     

Negative control by Sandostatin on pancreatic and duodenal growth: a possible implication of insulin-like growth factor I

This study was undertaken to evaluate the effects of Sandostatin, a potent somatostatin analogue, on pancreatic and intestinal growth and plasma and pancreatic levels of insulin-like growth factor I, a known growth factor. Rats weighing 320-330 g, equipped with an intravenous cannula were infused with either bovine serum albumin or Sandostatin at a dose of 5 micrograms kg-1 h-1 for 7 days. Sandostatin caused significant reductions in pancreatic and intestinal weights accompanied by decreases in total DNA, RNA in both organs and total protein in the intestine while total pancreatic enzymes were increased. Plasma cholecystokinin and insulin-like growth factor I were reduced whereas total insulin-like growth factor I pancreatic content was increased. It is suggested that Sandostatin may reduce growth of these two organs by decreasing cholecystokinin and insulin-like growth factor release and their specific effects at the pancreatic and duodenal cellular level.     

Boundary-Free Metal–Organic Framework Glasses Enable Highly Stable All-Solid-State Lithium–Oxygen Battery

Rechargeable lithium–oxygen batteries (LOBs) are considered to be one of the most promising energy storage systems. However, the use of reactive lithium (Li) metal and the formation of Li dendrites during battery operation would lead to serious safety concerns, especially when flammable liquid electrolytes are utilized. Herein, superior metal–organic framework (MOF) glass-based solid-state electrolytes (SSEs) is developed for stable all-solid-state LOBs (SSLOBs). These non-flammable and boundary-free MOF glass SSEs are capable of suppressing the dendrite growth and exhibiting long-term Li stripping/plating stability, contributing to superior Li⁺ conductivity (5 × 10⁻⁴ S cm⁻¹ at 20 °C), high Li⁺ transference number (0.86), and good electrochemical stability. It is discovered that discharge product deposition behavior in the solid-solid interface can be well regulated by the ion/electron mixed conducted cathode fabricated with MOF glass SSEs and electronic conductive polymers. As a result, the SSLOBs can be stably recharged for 400 cycles with a low polarization gap and deliver a high capacity of 13552 mAh g⁻¹. The development of this proposed MOF glass displays great application potential in energy storage systems with good safety and high energy density.     

Molecular characterization and expression analysis of a complement component 3 in the sea cucumber (Apostichopus japonicus)

The complement system has been discovered in invertebrates and vertebrates, and plays a crucial role in the innate defense against common pathogens. As a central component in the complement system, complement component 3 (C3) is an intermediary between innate and adaptive immune system. In this study, a new isoform of C3 in the sea cucumber Apostichopus japonicus, termed AjC3-2 was identified. Its open reading frame (ORF) is 5085?bp and encodes for 1695 amino acids with a putative signal peptide of 20 amino acid residues. The mature protein molecular weight of AjC3-2 was 187.72?kDa. It has a conserved thioester site and a linker R(689)RRR(692) where AjC3-2 is splitted into β and α chain during posttranslational modification. The expression patterns of two distinct sea cucumber C3 genes, AjC3-2 and AjC3, were similar. During the different development stages from unfertilized egg to juvenile of the sea cucumber, the highest expression levels of AjC3-2 and AjC3 genes were both found in late auricularia. In the adult, the highest expression of these two genes was observed in the coelomocytes and followed by the body wall. AjC3-2 and AjC3 genes expression increased significantly at 6?h after the LPS challenge. These results indicated that these two C3 genes play a pivotal role in immune responses to the bacterial infection in sea cucumber.