Hepatitis C virus inhibits AKT-tuberous sclerosis complex (TSC), the mechanistic target of rapamycin (MTOR) pathway,through endoplasmic reticulum stress to induce autophagy

Hepatitis C virus (HCV) is able to induce autophagy via endoplasmic reticulum (ER) stress, but the exact molecular signaling pathway is not well understood. We found that the activity of the mechanistic target of rapamycin complex 1 (MTORC1) was inhibited in Huh7 cells either harboring HCV-N (genotype 1b) full-genomic replicon or infected with JFH1 (genotype 2a) virus, which led to the activation of UNC-51-like kinase 1 (ULK1) and thus to autophagy. We then analyzed activity upstream of MTORC1, and found that both protein kinase, AMP-activated, α (PRKAA, including PRKAA1 and PRKAA2, also known as AMP-activated protein kinase, AMPKα) and AKT (refers to pan AKT, including three isoforms of AKT1-3, also known as protein kinase B, PKB) were inhibited by HCV infection. The inhibition of the AKT-TSC-MTORC1 pathway contributed to upregulating autophagy, but inhibition of PRKAA downregulated autophagy. The net effect on autophagy was from AKT, which overrode the inhibition effect from PRKAA. It was further found that HCV-induced ER stress was responsible for the inhibition of the AKT pathway. Metformin, a PRKAA agonist, inhibited HCV replication not only by activating PRKAA as previously reported, but also by activating AKT independently of the autophagy pathway. Taken together, our data suggested HCV inhibited the AKT-TSC-MTORC1 pathway via ER stress, resulting in autophagy, which may contribute to the establishment of the HCV-induced autophagy.     

RNA-binding protein Csx1 is phosphorylated by LAMMER kinase, Lkh1, in response to oxidative stress in Schizosaccharomyces pombe

Recent studies have shown that global gene expression during oxidative stress in Schizosaccharomyces pombe is regulated by stress-induced activation and binding of Csx1 to atf1(+) mRNA. However, the kinase responsible for the activation of Csx1 has not been identified. Here, we describe, for the first time, that Csx1 is phosphorylated by S. pombe LAMMER kinase, Lkh1, under oxidative conditions and that the stress-activated binding of the Csx1 to the atf1(+) mRNA was also affected by Lkh1 and Spc1. These data indicate that concerted actions of Spc1 and Lkh1 are required for the activation of Csx1 during oxidative condition in the fission yeast S. pombe.     

<Emphasis Type="Italic">Sphingomonas humi</Emphasis> sp. nov., isolated from soil

A Gram-negative, non-motile, non-spore-forming, small, orange, rod-shaped bacterium was isolated from soil in South Korea and characterized to determine its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequence examination revealed that strain PB323^T belongs to the family Sphingomonadaceae. The highest degree of sequence similarity was found with Sphingomonas kaistensis PB56^T (98.9%), followed by Sphingomonas astaxanthinifaciens TDMA-17^T (98.3%). Chemotaxonomic characteristics (the G+C content of the genomic DNA 69.0 mol%, Q-10 quinone system, C_18:1 ω7c/ω9t/ω12t, C_16:1 ω7c/C_15:0 iso 2OH, C_17:1 ω6c, and C16:0 as the major fatty acids) corroborated assignment of strain PB323^T to the genus Sphingomonas. Results of physiological and biochemical tests clearly demonstrate that strain PB323^T represents a distinct species and support its affiliation with the genus Sphingomonas. Based on these data, PB323^T (=KCTC 12341^T =JCM 16603T =KEMB 9004-003^T) should be classified as a type strain of a novel species, for which the name Sphingomonas humi sp. nov. is proposed.     

Anti-apoptotic effect of magnolol in myocardial ischemia and reperfusion injury requires extracellular signal-regulated kinase1/2 pathways in rat in vivo

Magnolol, an active component extracted from Magnolia officinalis, has been reported to have protective effect on ischemia and reperfusion (I/R)-induced injury in experimental animals. The aim of the present investigation was to further evaluate the mechanism(s) by which magnolol reduces I/R-induced myocardial injury in rats in vivo. Under anesthesia, left anterior descending (LAD) coronary artery was occluded for 30 min followed by reperfusion for 24 h (for infarct size and cardiac function analysis). In some experiments, reperfusion was limited to 1 h or 6 h for analysis of biochemical and molecular events. Magnolol and DMSO solution (vehicle) were injected intra-peritoneally 1 h prior to I/R insult. The infarct size was measured by TTC technique and heart function was monitored by Millar Catheter. Apoptosis related events such as p-ERK, p-Bad, Bcl-xl and cytochrome c expression were evaluated by Western blot analysis and myocardial caspase-3 activity was also measured. Magnolol (10 mg/kg) reduced infarct size by 50% (P < 0.01 versus vehicle), and also improved I/R-induced myocardial dysfunction. Left ventricular systolic pressure and positive and negative maximal values of the first derivative of left ventricular pressure (dP/dt) were significantly improved in magnolol-treated rats. Magnolol increased the expression of phosphor ERK and Bad which resulted in inhibition of myocardial apoptosis as evidenced by TUNEL analysis and DNA laddering experiments. Application of PD 98059, a selective MEK1/2 inhibitor, strongly antagonized the effect of magnolol. Taken together, we concluded that magnolol inhibits apoptosis through enhancing the activation of ERK1/2 and modulation of the Bcl-xl proteins which brings about reduction of infarct size and improvement of cardiac function in I/R-induced injury.     

The Role of HSPA12B in Regulating Neuronal Apoptosis

Heat shock protein A12B (HSPA12B) is the newest member of a recently defined subfamily of proteins distantly related to the 70-kDa family of heat shock proteins (HSP70) family. HSP70s play a crucial role in protecting cells, tissues, organs and animals from various noxious conditions. Here we studied the dynamic expression changes and localization of HSPA12B after middle cerebral artery occlusion (MCAO) with reperfusion induced ischemic insult processes in adult rats. Apoptosis, as indicated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, was also increased in the peri-ischemic cortex compared to non-ischemic hemisphere. The expression of HSPA12B was strongly induced in the ischemic hemisphere of MCAO reperfusion rats in vivo. In vitro studies indicated that the up-regulation of HSPA12B may be involved in oxygen-glucose deprivation-induced PC12 cell death. And knockdown of HSPA12B in cultured differentiated PC12 cells by siRNA showed that HSPA12B inhibited the expression of active caspase-3. Collectively, these results suggested that HSPA12B may be required for protecting neurons from ischemic insults.     

高压力制备柯萨奇病毒疫苗

以HeLa细胞和BALB／c小鼠为模型,研究了高压力对柯萨B组病毒（CVB）感染活性和免疫原性的影响,发现在230MPa压力下,结合其他相应的物理条件,CVB的感染活性可完全消失。该CVB仍具有抗原性,可诱导小鼠产生CVB特异性抗性,效价可达1：1500。用高压力处理的CVB免疫小鼠,再用正常CVB攻击,其生存率为67％,具有疫苗的特性。这些结果表明,高压力处理的CVB具有免疫保护作用,可作为一种具有潜在应用前景的病毒疫苗。     

Ameliorative symbiosis of endophyte (Penicillium funiculosum LHL06) under salt stress elevated plant growth of Glycine max L.

Experiments were conducted to investigate the role of a newly isolated endophytic fungus GMC-2A on physiology of host plant (Glycine max. L cv. Hwangkeum-kong) growing under salinity stress. GMC-2A was identified as a new strain of Penicillium funiculosum on the basis of sequence homology and phylogenetic analysis of D1/D2 regions of 28S rDNA. Preliminary screening experiment showed that the culture filtrate (CF) of GMC-2A promoted the growth of Waito-C, a dwarf gibberellin (GA) biosynthesis mutant rice cultivar. Analysis of fungal CF revealed the presence of GAs (GA₁ 1.53 ng/ml; GA₄ 9.34 ng/ml; GA₈ 1.21 ng/ml; GA₉ 37.87 ng/ml) and indole acetic acid (14.85 μg/ml). GMC-2A also showed high phosphate solubilization of tricalcium phosphate. Besides that, GMC-2A application enhanced soybean seed germination as compared to control. Under salinity stress (70 and 140 mM), GMC-2A significantly promoted the soybean growth attributes (shoot length, shoot fresh/dry biomass, chlorophyll content, photosynthesis rate and leaf area) in comparison to control treatments. We also observed low endogenous abscisic acid and elevated jasmonic acid contents in GMC-2A treated plants under salt stress. GMC-2A treatment significantly enhanced levels of isoflavones (34.22% and 75.37%) under salinity stress as compared to control. In conclusion, P. funiculosum LHL06 has significantly ameliorated the adverse effects of salinity induced abiotic stress, and re-programmed soybean to higher growth and isoflavone biosynthesis.     

Molecular Cloning of a Vernalization related cDNA Clone (Vrc) of Vrc79 in Winter Wheat (Triticum aestivum L.)

Vernalization is an essential factor in the flowering development of cold-required plants. There is a key stage of nucleic acid metabolism in the process of vernalization in winter wheat. To probe into the molecular determinants of vernalization, a cDNA library presumably enriching vernalization-related genes was prepared by specially expressed mRNAs from winter wheat ( Triticum aestivum L. cv. Jingdong No. 1) plumules at the key stage of 21 d vernalization being recovered as cDNAs after subtraction with mRNAs from nonvernalized and devernalized plumules. One vernalization-related cDNA clone (Vrc), Vrc79, which was only expressed at the key stage of 21 d vernalization, but not at other stages of nonvernalization, 4 d vernalization and devemalization, was isolated by differential screening of the library, and shown to be a vernalization-specific clone by Northern blot. Result of homology search suggested that Vrc79 was a novel gene identified in higher plant which was different from the cold-stress-induced genes and might play an important role in the floral induction in vernalization-requiring plants.     

Complete nucleotide sequence and organization of the mitogenome of the silk moth Caligula boisduvalii (Lepidoptera: Saturniidae) and comparison with other lepidopteran insects

The 15,360-bp long complete mitogenome of Caligula boisduvalii possesses a gene arrangement and content identical to other completely sequenced lepidopteran mitogenomes, but different from the common arrangement found in most insect order, as the result of the movement of tRNA(Met) to a position 5'-upstream of tRNA Ile. The 330-bp A+T-rich region is apparently capable of forming a stem-and-loop structure, which harbors the conserved flanking sequences at both ends. Dissimilar to what has been seen in other sequenced lepidopteran insects, the initiation codon for C. boisduvalii COI appears to be TTG, which is a rare, but apparently possible initiation codon. The ATP8, ATP6, ND4L, and ND6 genes, which neighbor another PCG at their 3' end, all harbored potential sequences for the formation of a hairpin structure. This is suggestive of the importance of such structures for the precise cleavage of the mRNA of mature PCGs. Phylogenetic analyses of available sequenced species of Bombycoidea, Pyraloidea, and Tortricidea supported the morphology-based current hypothesis that Bombycoidea and Pyraloidea are monophyletic (Obtectomera). As previously suggested, Bombycidae (Bombyx mori and B. mandarina) and Saturniidae (Antheraea pernyi and C. boisduvalii) formed a reciprocal monophyletic group.