黑木耳8808菌株生物学特性研究

黑木耳8808菌株,是笔者几年来,从黑龙江省15个地区,采集的32个样本中,分离的59个野生菌株中,经多次培养、比较,栽培试验选出的一株优质、高产菌株。该菌株1992年,在本省五常县长山乡生产150万袋,全省生产近1000万段,均获丰收,产量、质量均明显优于原生产菌株。为更好的为生产提供科学依据,本文研究了该木耳孢子弹射及萌发特征,菌丝、子实体、孢子形态,不同温度、pH、氮碳源浓度,不同培养料配方对该木耳菌丝生长及产实影响。     

The synergy of germline C634Y and V292M RET mutations in a northern Chinese family with multiple endocrine neoplasia type 2A

Genetic analysis for germline mutations of RET proto‐oncogene has provided a basis for individual management of medullary thyroid carcinoma (MTC) and pheochromocytoma. Most of compound mutations have more aggressive phenotypes than single point mutations, but the compound C634Y/V292M variant in MTC has never been reported. Thus, we retrospectively investigated synergistic effect of C634Y and V292M RET germline mutations in family members with multiple endocrine neoplasia type 2A. Nine of 14 family members in a northern Chinese family underwent RET mutation screening using next‐generation sequencing and PCR followed by direct bidirectional DNA sequencing. Clinical features of nine individuals were retrospectively carefully reviewed. In vitro, the scratch‐wound assay was used to investigate the difference between the cells carrying different mutations. We find no patients died of MTC. All 3 carriers of the V292M variant were asymptomatic and did not have biochemical or structural evidence of disease (age: 82, 62 and 58). Among 4 C634Y mutation carriers, 2 patients had elevated calcitonin with the highest (156 pg/mL) in an 87‐year‐old male. Two carriers of compound C634Y/V292M trans variant had bilateral MTC with pheochromocytoma or lymph node metastasis (age: 54 and 41 years, respectively). Further, the compound C634Y/V292M variant had a faster migration rate than either single point mutation in vitro (P < .05). In conclusion, the V292M RET variant could be classified as ‘likely benign’ according to ACMG (2015). The compound variant V292M/C634Y was associated with both more aggressive clinical phenotype and faster cell growth in vitro than was either single mutation.     

FGFRL1 affects chemoresistance of small‐cell lung cancer by modulating the PI3K/Akt pathway via ENO1

Fibroblast growth factor receptor‐like 1 (FGFRL1), a member of the FGFR family, has been demonstrated to play important roles in various cancers. However, the role of FGFRL1 in small‐cell lung cancer (SCLC) remains unclear. Our study aimed to investigate the role of FGFRL1 in chemoresistance of SCLC and elucidate the possible molecular mechanism. We found that FGFRL1 levels are significantly up‐regulated in multidrug‐resistant SCLC cells (H69AR and H446DDP) compared with the sensitive parental cells (H69 and H446). In addition, clinical samples showed that FGFRL1 was overexpressed in SCLC tissues, and high FGFRL1 expression was associated with the clinical stage, chemotherapy response and survival time of SCLC patients. Knockdown of FGFRL1 in chemoresistant SCLC cells increased chemosensitivity by increasing cell apoptosis and cell cycle arrest, whereas overexpression of FGFRL1 in chemosensitive SCLC cells produced the opposite results. Mechanistic investigations showed that FGFRL1 interacts with ENO1, and FGFRL1 was found to regulate the expression of ENO1 and its downstream signalling pathway (the PI3K/Akt pathway) in SCLC cells. In brief, our study demonstrated that FGFRL1 modulates chemoresistance of SCLC by regulating the ENO1‐PI3K/Akt pathway. FGFRL1 may be a predictor and a potential therapeutic target for chemoresistance in SCLC.     

芍药苷对巨细胞病毒感染小鼠脑组织损伤及海马神经元细胞凋亡的影响

海马组织在学习、记忆中发挥着重要作用,而且海马组织对巨细胞病毒(Cytomegalovirus,CMV)感染非常敏感,会使海马组织中的神经元大量丢失,神经元细胞发生凋亡.芍药苷可以减轻小鼠炎性脑损伤,其可能与提高机体抗氧化能力、清除体内自由基有关,但是芍药苷在CMV感染小鼠中研究甚少.为探讨芍药苷对CMV感染小鼠脑组织损伤及海马神经元细胞凋亡的影响,本研究将新生昆明小鼠随机分为4组:对照组、小鼠巨细胞病毒组(MCMV组)、芍药苷低剂量组(Pae-L组)和芍药苷高剂量组(Pae-H组),后三组通过腹腔注射MCMV病毒悬液建立模型,之后对照组和MCMV组经腹腔注射生理盐水,Pae-L组经腹腔注射10 mg/kg芍药苷,Pae-H组经腹腔注射30 mg/kg芍药苷;荧光定量PCR检测各组小鼠脑组织中MCMV-DNA载量的变化;Morris水迷宫检测各组小鼠学习记忆功能指标的变化;蛋白质免疫印迹(Western Blot)检测各组小鼠脑组织中MMP-9的表达变化;NeuN免疫染色检测各组小鼠海马组织中NeuN阳性细胞的变化;TUNEL染色检测各组小鼠海马组织中神经元细胞凋亡的变化;Western Blot检测各组小鼠海马组织中Bax、Bcl-2蛋白表达的变化.结果显示,与对照组比较,MCMV组小鼠的逃避潜伏期明显增加,穿越平台次数明显减少,脑组织中MMP-9蛋白表达水平显著上调,海马组织中NeuN阳性细胞数目显著减少,海马组织中神经元细胞凋亡指数显著增加,海马组织中Bax蛋白表达水平显著上调,Bcl-2蛋白表达水平显著下调;与MCMV组比较,Pae-L组和Pae-H组小鼠脑组织中MCMV-DNA载量减少,逃避潜伏期减少,穿越平台次数增加,脑组织中MMP-9蛋白表达水平下调,海马组织中NeuN阳性细胞数目增加,海马组织中神经元细胞凋亡指数减少,海马组织中Bax蛋白表达水平下调,Bcl-2蛋白表达水平明显上调.本研究提示,芍药苷能够改善MCMV感染引起的脑损伤,减轻海马组织中神经元细胞的凋亡.     

Investigation on bioactive protection of the amino acids derived from LEA protein on insulin by molecular simulation

Nowadays heat-sensitive protein medicines are increasingly showing their importance in the treatment of various diseases. Their popularisation and application are meeting a great challenge because of their heat lability. In this study, human insulin as a heat-sensitive protein medicine and 66 amino acids derived from a Group 3 late embryogenesis abundant protein fragment as a complex bioactive protectant, were chosen to be investigated to determine whether these amino acids can be used to protect the insulin from denaturation due to drying. The experiments were carried out by using a replica exchange molecular dynamics (REMD) simulation and GROMACS software with Gromos96 (53a6) force field. The REMD results indicate that those amino acids can effectively prevent the reversal between hydrophilic and hydrophobic surface. Both the configurations and secondary structures of the protected insulin were preserved very well. The H-bonding and electrostatic interactions between the insulin and the protectant play key roles in the bioactive protection of insulin. These results agree well with the water replacement hypothesis. All the results prove that these amino acids are a perfect bioactive protectant for heat-sensitive protein medicines.     

A family 5 β-mannanase from the thermophilic fungus Thielavia arenaria XZ7 with typical thermophilic enzyme features

A novel β-mannanase gene, man5XZ7, was cloned from thermophilic fungus Thielavia arenaria XZ7, and successfully expressed in Pichia pastoris. The gene (1,110 bp) encodes a 369-amino acid polypeptide with a molecular mass of approximately 40.8 kDa. The deduced sequence of Man5XZ7 consists of a putative 17-residue signal peptide and a catalytic module belonging to glycoside hydrolase (GH) family 5, and displays 76 % identity with the experimentally verified GH 5 endo-β-1,4-mannanase from Podospora anserina. Recombinant Man5XZ7 was optimally active at 75 °C and pH?5.0 and exhibited high activity at a wide temperature range (>50.0 % activity at 50–85 °C). Moreover, it had good adaptability to acidic to basic pH (>74.1 % activity at pH?4.0–7.0 and 25.6 % even at pH?9.0) and good stability from pH?3.0 to 10.0. These enzymatic properties showed that Man5XZ7 was a new thermophilic and alkali-tolerant β-mannanase. Further amino acid composition analysis indicated that Man5XZ7 has several characteristic features of thermophilic enzymes.     

Probiotic properties of Enterococcus strains isolated from traditional naturally fermented cream in China

The purpose of this study was to evaluate the probiotic properties of Enterococcus strains isolated from traditional naturally fermented cream in China. Four Enterococcus isolates showed high cholesterol removal ability in media were identified as Enterococcus durans (KLDS 6.0930 and 6.0933) and Enterococcus faecalis (KLDS 6.0934 and 6.0935) by 16S rRNA and pheS gene sequences, respectively, and selected for further evaluation. In order to assess the probiotic potential and safety of these strains, the property of four Enterococcus strains were examined, including acid and bile tolerance, adherence to Caco‐2 cells and antibiotics susceptibility. All four strains showed potential cholesterol assimilation, de‐conjugation of bile salts and/or cholesterol degradation to remove cholesterol in vitro. In addition, the potential effect of E. durans KLDS 6.0930 on serum cholesterol levels was evaluated in Sprague‐Dawley rats. After 4 weeks administration, compared with rats fed a high‐cholesterol diet without lactic acid bacteria supplementation, there was a significant (P < 0.05) decrease in the total cholesterol and low‐density lipoprotein cholesterol levels in the serum of rats treated with KLDS 6.0930. Furthermore, total bile acid level in the feces was significantly (P < 0.05) increased after KLDS 6.0930 administration. These observations suggested that the strain E. durans KLDS 6.0930 may be used in the future as a good candidate for lowering human serum cholesterol levels.     

Hypobaric hypoxia regulates iron metabolism in rats

Intermittent hypobaric hypoxia can produce a protective effect on both the nervous system and non-nervous system tissues. Intermittent hypobaric hypoxia preconditioning has been shown to protect rats from cardiac ischemia-reperfusion injury by decreasing cardiac iron levels and reactive oxygen species (ROS) production, thereby decreasing oxidative stress to achieve protection. However, the specific mechanism underlying the protective effect of hypobaric hypoxia is unclear. To shed light on this phenomenon, we subjected Sprague-Dawley rats to hypobaric hypoxic preconditioning (8 hours/day). The treatment was continued for 4 weeks. We then measured the iron content in the heart, liver, spleen, and kidney. The iron levels in all of the assessed tissues decreased significantly after hypobaric hypoxia treatment, corroborating previous results that hypobaric hypoxia may produce its protective effect by decreasing ROS production by limiting the levels of catalytic iron in the tissue. We next assessed the expression levels of several proteins involved in iron metabolism (transferrin receptor, L-ferritin, and ferroportin1 [FPN1]). The increased transferrin receptor and decreased L-ferritin levels after hypobaric hypoxia were indicative of a low-iron phenotype, while FPN1 levels remained unchanged. We also examined hepcidin, transmembrane serine proteases 6 (TMPRSS6), erythroferrone (ERFE), and erythropoietin (EPO) levels, all of which play a role in the regulation of systemic iron metabolism. The expression of hepcidin decreased significantly after hypobaric hypoxia treatment, whereas the expression of TMPRSS6 and ERFE and EPO increased sharply. Finally, we measured serum iron and total iron binding capacity in the serum, as well as red blood cell count, mean corpuscular volume, hematocrit, red blood cell distribution width SD, and red blood cell distribution width CV. As expected, all of these values increased after the hypobaric hypoxia treatment. Taken together, our results show that hypobaric hypoxia can stimulate erythropoiesis, which systemically draws iron away from nonhematopoietic tissue through decreased hepcidin levels.