Augmentation of NKT and NK cell-mediated cytotoxicity by peptidoglycan monomer linked with zinc

BACKGROUND: Peptidoglycan monomer (PGM), which was originally prepared by biosynthesis from culture fluids of penicillin-treated Brevibacterium divaricatum, is an immunostimulator, the activities of which might be improved by addition of zinc (Zn) to the basic molecule. METHODS: To test the possible cytotoxic effects of this new analogue, we analyzed the ability of PGM-Zn and PGM to change the phenotypic profile of hepatic and splenic mononuclear lymphatic cells and to affect the growth of malignant T-cell line YAC-1 and syngeneic thymocytes. RESULTS: Pretreatment of C57BL/6 mice primarily with PGM-Zn over 6 days (10/mg/kg intraperitoneally) significantly enhanced the proportions of NK1.1high+, CD4-CD8-, CD69+, and CD3intermediate/NK1.1+/IL2R-beta+ (NKT) cells in the liver, and major histocompatibility complex class II+, CD69+, and CD8+ cells in the spleen. Both types of cells were highly cytotoxic against YAC-1 and syngeneic thymocytes, increasing the destruction of YAC-1 by 70% on addition of hepatic cells and by 30% on addition of splenic cells. Destruction of thymocytes increased by 10 and 50%, respectively. CONCLUSION: The results point to PGM-Zn as a potent cytotoxicity-inducing agent, which also generates autoreactive NKT cells.     

mnd2: A New Mouse Model of Inherited Motor Neuron Disease

The autosomal recessive mutation mnd2 results in early onset motor neuron disease with rapidly progressive paralysis, severe muscle wasting, regression of thymus and spleen, and death before 40 days of age. mnd2 has been mapped to mouse chromosome 6 with the gene order: centromere-Tcrb-Ly-2-Sftp-3-D6Mit4-mnd2-D6Mit6, D6Mit9-D6Rck132-Raf-1, D6Mit11-D6Mit12-D6Mit14. mnd2 is located within a conserved linkage group with homologs on human chromosome 2p12-p13. Spinal motor neurons of homozygous affected animals are swollen and stain weakly, and electromyography revealed spontaneous activity characteristic of muscle denervation. Myelin staining was normal throughout the neuraxis. The clinical observations are consistent with a primary abnormality of lower motor neuron function. This new animal model will be of value for identification of a genetic defect responsible for motor neuron disease and for evaluation of new therapies.     

Morpho-Physiological and Antioxidant Traits of Marigold cv. ‘Sparse Petal’ and ‘Compact Petal’ as Influenced by Irrigation Intervals

The effect of irrigation intervals was studied on physiological, morphological, and antioxidant traits of two marigold (Calendula officinalis L.) cultivars in Karaj, Iran, in a split-plot experiment based on a randomized complete block design with three replications. The experimental treatments included irrigation at three levels of I1 (irrigation interval of 3 days), I2 (irrigation interval of 5 days), and I3 (irrigation interval of 7 days) as the main plot and cultivar at two levels of V1 (cv. ‘sparse petal’) and V2 (cv. ‘compact petal’) as the sub-plot. The results based on the comparison of the means showed that the increase in irrigation interval from 3 to 7 days decreased the leaf area index, crop growth rate, relative growth rate, and net assimilation rate by 73.53, 85.76, 93.47, and 94.81%, respectively. It also decreased the flower yield, plant height, flower number, and leaf number by 71.92, 41.84, 99.31, and 58.67%, respectively. The interaction between irrigation and cultivar revealed that I3V1 had the highest total phenol content (3013.59 g gallic acid 100 g^?1 tissue) and antioxidant capacity (60.8%). It can be inferred that the treatment of I1 and cv. ‘compact petal’ give the best results for flower yield and physiological and morphological traits, and the treatment of I3 and both cultivars provide the best results for antioxidant traits in the climatic conditions of the Karaj region.

     

细菌金属离子外排系统及金属稳态调控

铁、铜、锌、锰等金属离子是各类生物体生存和增殖所必需的微量元素,可影响生物体内蛋白酶活性、免疫反应、生理过程和抗感染机制。细菌感染过程中,宿主可通过限制或提高体内环境中金属离子的浓度来抑制细菌增殖,与此同时,细菌进化出各种转运系统以适应宿主体内金属离子水平的变化。由于不同细菌的金属离子外排系统在结构和生化特性上存在变异,它们呈现出独特的金属离子外排模式。本文根据现有文献报道及本团队研究结果,对铁、铜、锌和锰离子的细菌外排系统进行讨论和总结,旨在综述目前对细菌金属离子稳态调控机制研究进展的认识,为深入理解细菌金属稳态调控相关机制提供参考。     

Inhibition of antigen presentation by the glycine/alanine repeat domain is not conserved in simian homologues of Epstein-Barr virus nuclear antigen 1.

Most humans and Old World nonhuman primates are infected for life with Epstein-Barr virus (EBV) or closely related gammaherpesviruses in the same lymphocryptovirus (LCV) subgroup. Several potential strategies for immune evasion and persistence have been proposed based on studies of EBV infection in humans, but it has been difficult to test their actual contribution experimentally. Interest has focused on the EBV nuclear antigen 1 (EBNA1) because of its essential role in the maintenance and replication of the episomal viral genome in latently infected cells and because EBNA1 endogenously expressed in these cells is protected from presentation to the major histocompatibility complex class-I restricted cytotoxic T-lymphocyte (CTL) response through the action of an internal glycine-alanine repeat (GAR). Given the high degree of biologic conservation among LCVs which infect humans and Old World primates, we hypothesized that strategies essential for viral persistence would be well conserved among viruses of this subgroup. We show that the rhesus LCV EBNA1 shares sequence homology with the EBV and baboon LCV EBNA1 and that the rhesus LCV EBNA1 is a functional homologue for EBV EBNA1-dependent plasmid maintenance and replication. Interestingly, all three LCVs possess a GAR domain, but the baboon and rhesus LCV EBNA1 GARs fail to inhibit antigen processing and presentation as determined by using three different in vitro CTL assays. These studies suggest that inhibition of antigen processing and presentation by the EBNA1 GAR may not be an essential mechanism for persistent infection by all LCV and that other mechanisms may be important for immune evasion during LCV infection.     

Aflatoxin-producing Aspergillus species from saffron field soils in the South Khorasan province of Iran

The aim of the present study was to isolate and identify Aspergillus species associated with saffron plants in the city of Birjand (South Khorasan Province, Iran) as well as to assess their aflatoxin B1 production. Sampling was performed during 2013–2014 crop season. Aspergillus species were isolated and purified using general and specific culture media. Growth rates and macroscopic and microscopic characteristics of the isolates were determined using yeast extract, Czapek yeast extract, malt extract and creatine sucrose agar media at 25 and 37 °C. DNA was extracted by the modified CTAB method and beta-tubulin, calmodulin and internal transcribed spacer genes were amplified and sequenced. Phylogenetic position of the isolates was determined against other Aspergillus species. Thin layer chromatography was used to investigate the production of aflatoxin B1 by Aspergillus isolates. Based on the morphological characteristics, shape and colour of the colonies, and sequencing results, the isolates belonged to Aspergillus terreus, A. flavus, A. flavipes and A. niger species. Only A. flavus isolates were aflatoxin B1 producers. We concluded that the soil of the studied saffron fields contained several species of Aspergillus, with A. flavus significantly affecting crop production through contamination of the crop by aflatoxin.     

Chemical constituents of Euphorbia marschalliana Boiss

Acetone extract of aerial parts of Euphorbia marschalliana collected from Iran has been subjected to different chromatography techniques for fractionation and purification. The stereo-structures of the myrsinol esters 15-O-acetyl-3-O-propionyl-5-O-butanoyl-7-O-nicotinoylmyrsinol (1) and 15-O-acetyl-3,5-O-dibutanoyl-7-O-nicotinoylmyrsinol (2) have been probed using ROESY spectroscopy and modified for the stereochemistry at C-6, C-12 and C-13. Beta-sitosterol (3), 29-norcycloart-5-ene (4), 5,8-lanostadiene-3beta-ol (5), 3beta,24(S),25-trihydroxycycloartane (6), 3beta,24(R),25-trihydroxycycloartane (7) and 24-methylenecycloartan-3beta-ol (8) were identified for the first time in this plant.     

Stimulation of prefrontal cortex at physiologically relevant frequencies inhibits dopamine release in the nucleus accumbens

The prefrontal cortex (PFC) is thought to provide an excitatory influence on the output of mesoaccumbens dopamine neurons. The evidence for this influence primarily arises from findings in the rat that chemical or high-intensity and high-frequency (60-200 Hz) electrical stimulations of PFC increase burst activity of midbrain dopamine neurons, and augment terminal release of dopamine in the nucleus accumbens. However, PFC neurons in animals that are engaged in PFC-dependent cognitive tasks increase their firing frequency from a baseline of 1-3 Hz to 7-10 Hz, suggesting that the commonly used high-frequency stimulation parameters of the PFC may not be relevant to the behavioral states that are associated with PFC activation. We investigated the influence of PFC activation at lower physiologically relevant frequencies on the release of dopamine in the nucleus accumbens. Using rapid (5-min) microdialysis measures of extracellular dopamine in the nucleus accumbens, we found that although PFC stimulation at 60 Hz produces the expected increases in accumbal dopamine release, the same amplitude of PFC stimulation at 10 Hz significantly decreased these levels. These results indicate that activation of PFC, at frequencies that are associated with increased cognitive demand on this region, inhibits the mesoaccumbens dopamine system.