Expression, purification, and characterization of the maltooligosyltrehalose trehalohydrolase from the thermophilic archaeon Sulfolobus solfataricus ATCC 35092

The maltooligosyltrehalose trehalohydrolase (MTHase) mainly cleaves the alpha-1,4-glucosidic linkage next to the alpha-1,1-linked terminal disaccharide of maltooligosyltrehalose to produce trehalose and the maltooligosaccharide with lower molecular mass. In this study, the treZ gene encoding MTHase was PCR-cloned from Sulfolobus solfataricus ATCC 35092 and then expressed in Escherichia coli. A high yield of the active wild-type MTHase, 13300 units/g of wet cells, was obtained in the absence of IPTG induction. Wild-type MTHase was purified sequentially using heat treatment, nucleic acid precipitation, and ion-exchange chromatography. The purified wild-type MTHase showed an apparent optimal pH of 5 and an optimal temperature at 85 degrees C. The enzyme was stable at pH values ranging from 3.5 to 11, and the activity was fully retained after a 2-h incubation at 45-85 degrees C. The k(cat) values of the enzyme for hydrolysis of maltooligosyltrehaloses with degree of polymerization (DP) 4-7 were 193, 1030, 1190, and 1230 s(-1), respectively, whereas the k(cat) values for glucose formation during hydrolysis of DP 4-7 maltooligosaccharides were 5.49, 17.7, 18.2, and 6.01 s(-1), respectively. The K(M) values of the enzyme for hydrolysis of DP 4-7 maltooligosyltrehaloses and those for maltooligosaccharides are similar at the same corresponding DPs. These results suggest that this MTHase could be used to produce trehalose at high temperatures.     

Simultaneous quantification of glyphosate, glufosinate, and their major metabolites in rice and soybean sprouts by gas chromatography with pulsed flame photometric detector

Procedures were developed for the simultaneous determination of glyphosate [N-(phosphonomethyl)glycine] and glufosinate [dl-homoalanin-4-yl-(methyl)phosphinic acid] and their major metabolites, aminomethylphosphonic acid (AMPA) and 3-(methylphosphinico)propionic acid (3-MPPA), in rice and soybean sprouts by gas chromatography (GC) equipped with a pulsed flame photometric detector (PFPD). Herbicides and their major metabolites were previously derivatized with TMOA (trimethyl orthoacetate (TMOA) in the presence of acetic acid, and their GC responses versus heating temperature (70-90 degrees C) and heating time (30-120 min) were optimized. It was found that increases in heating temperature and heating time were unfavorable for the derivatization of glyphosate or glufosinate, whereas high temperature and extended reaction time remarkably facilitated that of AMPA and 3-MPPA except at 90 degrees C for an extended reaction time (120 min). Combination of AG1-X8 anion-exchange chromatography with a Florisil cartridge cleanup process was favorable for the GC-PFPD analysis. Four types of derivatives spiked in rice and soybean sprout matrices were eluted, reaching a baseline separation, in a sequence of 3-MPPA, AMPA, glyphosate, and glufosinate within 14 min using a DB-608 capillary column. Recoveries of glyphosate, AMPA, glufosinate, and 3-MPPA (0.5 ppm) spiked in both sample matrices were determined to be 72-81, 71-86, 101-119, and 83-90%, respectively, whereas the coefficient of variation was determined to be <10% in three repeated determinations. The instrumental limits of detection for glyphosate, AMPA, glufosinate, and 3-MPPA in sample matrices were 0.02, 0.03, 0.02, and 0.01 ppm, respectively. The limits of quantification for glyphosate, AMPA, glufosinate, and 3-MPPA in sample matrices were 0.06, 0.10, 0.06, and 0.04 ppm, respectively.     

Anti-inflammatory potential of flavonoid contents from dried fruit of Crataegus pinnatifida in vitro and in vivo

The dried fruits of Crataegus pinnatifida, a local soft drink material and medical herb, demonstrated antioxidant effect in a previous study. The present study investigates the anti-inflammatory potential of flavonoid contents from dried fruit of C. pinnatifida (CF-Fs). The preliminary investigation showed that CF-Fs (0.25-0.75 mg/mL) decreased the release of PGE2 and nitric oxide as induced by lipopolysaccharide (LPS, an endotoxin) in macrophage RAW 264.7 cells. The in vivo assay showed that pretreatment of rats with CF-Fs (50-200 mg/kg dosed by gavage) for 5 days significantly decreased the serum levels of the hepatic enzyme markers alanine aminotransferase and aspartate aminotransferase induced by the 6-h treatment with LPS (i.p.; 5 mg/kg). Histopathological evaluation of the rat livers revealed that CF-Fs reduced the incidence of liver lesions such as neutrophil infiltration and necrosis induced by LPS. Furthermore, it was found that pretreatment with CF-Fs decreased the hepatic expression of iNOS and COX-2 induced by LPS in rats. These results demonstrate that CF-Fs present anti-inflammatory potential in vitro and in vivo and that they may play a role in hepatoprotection.     

螺旋藻属(Spirulina(Arthrospira))一新种(英文)

该文论述了螺旋藻属一新种 .该新种采集于内蒙古伊克昭盟毛乌素沙地巴彦淖尔湖 .通过光学显微镜、扫描和透射电子显微镜照片 ,描述了这一新种的形态特征 ,定名为巴彦淖尔螺旋藻 (Spirulina(Arthrospira)bayannurensisB .Sh .LietC .Qiaosp .nov .) .巴彦淖尔螺旋藻的模式标本存放在内蒙古农业大学植物标本室     

植物病害管理战略决策的一个量化模型

 从植物病害流行结构分析入手,导出了以Logistic模式描述病害流行系统管理战略决策的数学模型:Z=In((1-X₀)/X₀)-r*t,并给出了相应的使用准则。初步试用的结果表明:它不仅十分简便和经济,而且是值得信赖的。     

Induction of autophagy and apoptosis by the extract of Solanum nigrum Linn in HepG2 cells

Solanum nigrum L. (SN) has been used in traditional folk medicine to treat different cancers. It is also used as a hepatoprotective and anti-inflammatory agent. In this study, we demonstrated that the extract of SN (SNE) induced a strong cytotoxic effect toward HepG2 cells but much less to Chang liver and WRL-68 cells. The mechanisms of the cytotoxic effect were concentration-dependent. High doses of SNE (2 and 5 mg/mL) induced apoptotic cell death in HepG2 cells, as evidenced by increases in the expressions of p-JNK and Bax, mitochodrial release of cytochrome c, and caspase activation. On the other hand, cells treated with low concentrations of SNE (50-1000 microg/mL) revealed morphological and ultrastructural changes of autophagocytic death under electron microscopic observation. Furthermore, these cells showed increased levels of autophagic vacuoles and LC3-I and LC3-II proteins, specific markers of autophagy. The levels of Bcl-2 and Akt that have been implicated in the down-regulation of autophagy were decreased upon SNE treatment. Taken together, these findings indicate that SNE induced cell death in hepatoma cells via two distinct antineoplastic activities of SNE, the ability to induce apoptosis and autophagocytosis, therefore suggesting that it may provide leverage to treat liver cancer.     

Effects of different management practices on Portulaca oleracea emergence in soyabean

Portulaca oleracea (common purslane) is a summer annual weed with wide geographic distribution and is problematic in many crops worldwide. Field experiments were conducted to determine the effects of different management practices on P. oleracea emergence in soyabean fields. Two tillage systems [conventional tillage (CT) and no‐till (NT)], three soyabean seeding rates (SR) (200 000, 300 000 and 400 000 seeds ha^?1) and three imazethapyr doses (0, 50, and 100 g a.i. ha^?1 applied pre‐emergence) were considered as experimental factors. Portulaca oleracea emergence was affected by management practices including tillage system, soyabean SR and imazethapyr dose. Conventional tillage required a thermal time (TT) of 195.95 and 221.30 d °C to reach 50% emergence in 2016 and 2017, respectively, while for NT, the respective TT requirements were 182.34 and 203.32 d °C. On increasing soyabean SR from 200 000 to 400 000 seeds ha^?1, the TT requirements for 50% emergence (T₅₀) of P. oleracea also increased. The T₅₀ at the herbicide dose of 100 g a.i. ha^?1 was 193.05 and 220.67 d °C in 2016 and 2017, respectively, while for the non‐herbicide treatment, the respective TT requirements were 165.98 and 202.94 d °C. From an integrated weed management perspective, a combination of CT with a SR of 400 000 seeds ha^?1 and a 100 g a.i. ha^?1 imazethapyr dose not only resulted in the lowest P. oleracea seedling density m^?2 but also caused the longest delay in the time to reach the T₅₀. Findings from our study may facilitate the development of effective P. oleracea management strategies.     

颗粒分选速度与土体温度之关系

着重于从事同一堆积材料试体在不同温度下受振荡之上升速度的变化试验,采用粒径 3.9m m之百丽珠做为堆积材,底层堆积高度（H_d 分别为 4,8,12,18cm共 4种高度,于放置同粒径不同颜色之百丽珠做为追迹珠后,上层堆积厚度（H_u）为 2 cm,试体初始温度 t设定为 20,21,22,23,24,25,26,27,28,29,30,31℃等 12种温度一共 48种处理。每一处理 5重复试验得一追迹珠上升 2 cm所需时间（T）与试体温度（t）之关系式。     

Activation of rabbit TLR9 by different CpG-ODN optimized for mouse and human TLR9

Synthetic CpG-oligodeoxynucleotides (CpG-ODN) are potent adjuvants that accelerate and boost antigen-specific immune responses. Toll-like receptor 9 (TLR9) is the cellular receptor for these CpG-ODN. Previous studies have shown species-specific activation of mouse TLR9 (mTLR9) and human TLR9 (hTLR9) by their optimized CpG-ODN. The interaction between rabbit TLR9 (rabTLR9) and CpG-ODN, however, has not been previously investigated. Here, we cloned and characterized rabTLR9 and comparatively investigated the activation of the rabbit, mouse, and human TLR9 by CpG-ODN. The complete open reading frame of rabTLR9 encodes 1028 amino acid residues, which share 70.6% and 75.5% of the identities of mTLR9 and hTLR9, respectively. Rabbit TLR9 is preferentially expressed in immune cells rich tissues, and is localized in intracellular vesicles. While mTLR9 and hTLR9 displayed species-specific recognition of their optimized CpG-ODN, rabbit TLR9 was activated by these CpG-ODN without any preference. This result suggests that rabTLR9 has a broader ligand-recognition profile than mouse and human TLR9.     

Effect of lipopolysaccharide on intranasal administration of liposomal Newcastle disease virus vaccine to SPF chickens

In order to potentiate the low immunogenicity of the inactivated Newcastle disease virus immunized into chickens by mucosal route, liposomes as a drug delivery system and LPS (lipopolysaccharide) as an immuno-stimulator were evaluated. Here, we report a new nasal delivery system of inactivated Newcastle disease virus (NDV) vaccine. The intranasal vaccine was based on different lipids to form MLV (multi-lamellar vehicles) liposomes. The liposomes had combined carrier and adjuvant activities, which induced strong systemic (serum) and local (lung and nasal) humoral responses in SPF (specific-pathogen-free) chickens, and provided protective immunity. PC-Lip (phosphatidylcholine-liposome) elicited significant mucosal secretary immunoglobulin A (s-IgA) levels (p < 0.05) in tracheal lavage fluid and serum IgG levels (p < 0.05). In response to virulent viral challenge, birds treated with PBS (phosphate buffered saline) as control group died, whereas 80% of chickens which received PC-Lip, PC-Lip-LPS, PS-Lip (phosphatidylserine-liposome), and PS-Lip-LPS survived. HAI titers were 1:2560 in the PS-Lip-LPS group and 1:1280 in the PC-Lip, PC-Lip-LPS, and PS-Lip groups after two vaccinations. The results suggest that PC-Lip or PS-Lip might thus be suitable as a potential adjuvant for mucosal vaccination against NDV in chickens.