Nicotine-Induced Neuroprotection Against Ischemic Injury Involves Activation of Endocannabinoid System in Rats

Nicotine has been reported to exert certain protective effect in the Parkinson’s and Alzheimer’s diseases. Whether it has a similar action in focal cerebral ischemia was unclear. In the present study, rats received either an injection of (?)-nicotine hydrogen tartrate salt (1.2 mg/kg, i.p.) or the vehicle 2 h before the 120 min middle cerebral artery occlusion. Neurological deficits and histological injury were assessed at 24 h after reperfusion. The content of endocannabinoids and the expression of cannabinoid receptor CB1 in brain tissues were determined at different time points after nicotine administration. Results showed that nicotine administration ameliorated neurological deficits and reduced infarct volume induced by cerebral ischemia in the rats. The neuroprotective effect was partially reversed by CB1 blockage. The content of the endocannabinoids N-arachidonylethanolamine and 2-arachidonoylglycerol, as well as the expression of cannabinoid receptor CB1 were up-regulated in brain tissues after nicotine delivery. These results suggest that endogenous cannabinoid system is involved in the nicotine-induced neuroprotection against transient focal cerebral ischemia.     

Streptomyces sp. 173, an insecticidal micro-organism from marine

AIMS: To find new insecticidal antibiotics from marine micro-organisms. METHODS AND RESULTS: Strains isolated from seawater and sea sediments from Beidiahe and Dagang of the east coast of China were screened for their insecticidal qualities. The screening was carried out using bioassay of brine shrimp and the insect pest Helicoverpa armigera. The fermentation, preliminary extraction and isolation of Streptomyces sp.173 were carried out. CONCLUSIONS: In total 331 isolates were examined through bioassay of brine shrimp and 40 isolates (12.08%) showed potential insecticidal activities. Of the 40 isolates, one isolate, designated Streptomyces sp.173, was found to have strong insecticidal activity against both brine shrimp and H. armigera, similar to that of avermectin B1. SIGNIFICANCE AND IMPACT OF THE STUDY: The isolated Streptomyces sp.173 has great insecticidal potency. This work indicated that marine micro-organisms could be an important source of insecticidal antibiotics and the improved anti-brine shrimp bioassay is suitable for primary screening.     

光质对石刁柏愈伤组织培养中生长和过氧化物酶的影响

报道了在石刁柏愈伤组织培养中,采用５种不同光质处理,对愈伤组织生长及其过氧化物酶（ＰＯＤ）活性及同工酶的影响,实验表明,不同光质处理对生长有不同的效应,蓝光、红光下的培养物生长较快。不同光质对培养物质的ＰＯＤ活性亦有不同效应,ＰＯＤ同工酶谱亦有不同,蓝光、红光下的培养物,ＰＯＤ活性较高。ＰＯＤ活性变化与愈伤组织生长呈正相关。     

Ectopic overexpression of porcine DGAT1 increases intramuscular fat content in mouse skeletal muscle

The microsomal enzyme 1, 2-acyl CoA: diacylglyceroltransferase-1 (DGAT1) plays an important role in triglyceride storage in adipose tissue and expresses in skeletal muscle as well. The primary goal of the present study was to investigate the effect of porcine DGAT1 on intramuscular fat (IMF) content of transgenic mice produced by pronuclear microinjection with muscle specific promoter of porcine muscle creatine kinase (MCK). In normal chow-fed diet, 4 month-old male transgenic mice expressed more DGAT1, ACC1, UCP1, and FABP4 mRNAs and proteins in skeletal muscle than control mice by real-time PCR and western blot. No significant changes were detected for ACC2, CD36, ADRP, PPAR gamma and LPL. Triacylglycerol assay and soleus muscle sections showed overexpression of porcine DGAT1 in skeletal muscle increased intramyocellular triglyceride and percent of the total cell surface covered by lipid droplets. Thus, upregulation of porcine DGAT1 in skeletal muscle increases IMF content. The present study may further serve to develop transgenic pigs with higher IMF content and improved meat quality.     

寡齿新银鱼同工酶及其与幼态持续的关系

采用聚丙烯酰胺垂直板状连续电泳方法,对幼态持续(neoteny)的寡齿新银鱼(Neosalanx oligodontis Chen)13种同工酶的18个位点进行研究,并进行乳酸脱氢酶热变性实验。结果表明ADH、GOT、α-GPDH、LDH、MDH、ME、POX和SOD表现出一定的幼态持续的特征,其中LDH由A、B两个位点编码,C位点不表达,是因为个体发育早期C基因尚未表达时发生幼态持续的结果。ES和IDH无幼态持续特征。α-AMY、FUM和CAT因数据不足,未进行分析。寡齿新银鱼同工酶基因表达中幼态特征的表现为研究鱼类幼态持续的产生机制和遗传基础提供线索。     

The Highwire Ubiquitin Ligase Promotes Axonal Degeneration by Tuning Levels of Nmnat Protein

Axonal degeneration is a hallmark of many neuropathies, neurodegenerative diseases, and injuries. Here, using a Drosophila injury model, we have identified a highly conserved E3 ubiquitin ligase, Highwire (Hiw), as an important regulator of axonal and synaptic degeneration. Mutations in hiw strongly inhibit Wallerian degeneration in multiple neuron types and developmental stages. This new phenotype is mediated by a new downstream target of Hiw: the NAD+ biosynthetic enzyme nicotinamide mononucleotide adenyltransferase (Nmnat), which acts in parallel to a previously known target of Hiw, the Wallenda dileucine zipper kinase (Wnd/DLK) MAPKKK. Hiw promotes a rapid disappearance of Nmnat protein in the distal stump after injury. An increased level of Nmnat protein in hiw mutants is both required and sufficient to inhibit degeneration. Ectopically expressed mouse Nmnat2 is also subject to regulation by Hiw in distal axons and synapses. These findings implicate an important role for endogenous Nmnat and its regulation, via a conserved mechanism, in the initiation of axonal degeneration. Through independent regulation of Wnd/DLK, whose function is required for proximal axons to regenerate, Hiw plays a central role in coordinating both regenerative and degenerative responses to axonal injury.     

Akt, a Target of Phosphatidylinositol 3-Kinase, Inhibits Apoptosis in a Differentiating Neuronal Cell Line

Phosphatidylinositol (PI) 3-kinase has been suggested to mediate cell survival. Consistent with this possibility, apoptosis of conditionally (simian virus 40 T^ts) immortalized rat hippocampal H19-7 neuronal cells was increased in response to wortmannin, an inhibitor of PI 3-kinase. Downstream effectors of PI 3-kinase include Rac1, protein kinase C, and the serine-threonine kinase Akt (protein kinase B). Here, we show that activation of Akt is one mechanism by which PI 3-kinase can mediate survival of H19-7 cells during serum deprivation or differentiation. While ectopic expression of wild-type Akt (c-Akt) does not significantly enhance survival in H19-7 cells, expression of activated forms of Akt (v-Akt or myristoylated Akt) results in enhanced survival which can be comparable to that conferred by Bcl-2. Conversely, expression of a dominant-negative mutant of Akt accelerates cell death upon serum deprivation or differentiation. Finally, the results indicate that Akt can transduce a survival signal for differentiating neuronal cells through a mechanism that is independent of induction of Bcl-2 or Bcl-x_L or inhibition of Jun kinase activity.     

Morphological characterization of a novel scaffold for anterior cruciate ligament tissue engineering

Tissue engineering offers an interesting alternative to current anterior cruciate ligament (ACL) surgeries. Indeed, a tissue-engineered solution could ideally overcome the long-term complications due to actual ACL reconstruction by being gradually replaced by biological tissue. Key requirements concerning the ideal scaffold for ligament tissue engineering are numerous and concern its mechanical properties, biochemical nature, and morphology. This study is aimed at predicting the morphology of a novel scaffold for ligament tissue engineering, based on multilayer braided biodegradable copoly(lactic acid-co-(e-caprolactone)) (PLCL) fibers The process used to create the scaffold is briefly presented, and the degradations of the material before and after the scaffold processing are compared. The process offers varying parameters, such as the number of layers in the scaffold, the pitch length of the braid, and the fibers' diameter. The prediction of the morphology in terms of pore size distribution and pores interconnectivity as a function of these parameters is performed numerically using an original method based on a virtual scaffold. The virtual scaffold geometry and the prediction of pore size distribution are evaluated by comparison with experimental results. The presented process permits creation of a tailorable scaffold for ligament tissue engineering using basic equipment and from minimum amounts of raw material. The virtual scaffold geometry closely mimics the geometry of real scaffolds, and the prediction of the pore size distribution is found to be in good accordance with measurements on real scaffolds. The scaffold offers an interconnected network of pores the sizes of which are adjustable by playing on the process parameters and are able to match the ideal pore size reported for tissue ingrowth. The adjustability of the presented scaffold could permit its application in both classical ACL reconstructions and anatomical double-bundle reconstructions. The precise knowledge of the scaffold morphology using the virtual scaffold will be useful to interpret the activity of cells once it will be seeded into the scaffold. An interesting perspective of the present work is to perform a similar study aiming at predicting the mechanical response of the scaffold according to the same process parameters, by implanting the virtual scaffold into a finite element algorithm.     

Molecular Characterization of High Plant Species Using PCR with Primers Designed from Consensus Branch Point Signal Sequences

A novel method is introduced for producing molecular markers in plants using single 15- to 18-mer PCR primers designed from the short conserved consensus branch point signal sequences and standard agarose gel electrophoresis. This method was tested on cultivated peanut and verified to give good fingerprinting results in other plant species (mango, banana, and longan). These single primers, designed from relatively conserved branch point signal sequences within gene introns, should be universal across other plant species. The method is rapid, simple, and efficient, and it requires no sequence information of the plant genome of interest. It could be used in conjunction with, or as a substitute for, conventional RAPD or ISSR techniques for applications including genetic diversity analysis, phylogenetic tree construction, and quantitative trait locus mapping. This technique provides a new way to develop molecular markers for assessing genetic diversity of germplasm in diverse species based on conserved branch point signal sequences.