脑心肌炎病毒VP3蛋白抑制I型干扰素信号通路促进病毒体外增殖的研究

天然免疫是抵抗病原微生物感染的第一道防线,为探究病毒蛋白在脑心肌炎病毒感染引起的天然免疫应答过程中的作用机制以及对病毒体外复制的影响,本研究应用分子生物学技术构建结构蛋白VP3的表达载体p CMV-Myc-VP3,转染HEK293细胞后,使其在细胞内过表达;感染病毒后,通过实时荧光定量PCR和TCID50分别检测病毒的基因组拷贝数和病毒滴度,以此验证VP3蛋白表达对EMCV体外增殖的影响;另通过荧光定量PCR检测VP3过表达对EMCV引起的IFN-β和信号通路相关因子m RNA转录水平的影响。结果表明,VP3蛋白可促进EMCV在HEK293细胞内的增殖,初步探索发现VP3蛋白可显著抑制IFN-β的表达。WesternBlot检测发现体外表达VP3后,MAVS蛋白的表达明显减少,但对MDA5表达无影响。试验数据初步表明,VP3蛋白可以通过抑制MAVS的表达拮抗I型IFN信号通路的活化,进而促进病毒增殖。     

昆虫Hippo信号通路研究概述

Hippo信号通路是最早于果蝇(Drosophila melanogaster)中发现的一条调控器官大小的重要信号转导通路,昆虫、哺乳动物等多细胞生物中均存在此信号通路且在进化上高保守。Hippo通路不仅通过调节细胞增殖与凋亡精确控制着器官大小,亦参与调控干细胞自我更新及组织再生,并与多种人类肿瘤的发生密切相关。近10年来,基于果蝇模式的Hippo通路研究一直十分活跃并获得丰硕成果,此外,在家蚕(Bombyx mori)、棉铃虫(Heliothis armigera)等几种昆虫中也报道了相关结果。这些研究和成果显著增进了人们对Hippo通路的了解,不但有助于阐释Hippo通路调控器官大小的分子机制,而且对与之相关的人类肿瘤的治疗也具有重要指导意义。本文简要概述了昆虫Hippo通路的主要发现和研究进展,以期为以昆虫为模式的Hippo通路研究提供参考。     

JAK-STAT信号通路研究进展

信号通路JAK-STAT参与机体多种调节反应,在细胞因子等与其相应受体结合后激活JAK激酶,进一步活化其下游信号蛋白分子STAT,导致STAT同源或异源二聚体化,随后二聚体蛋白移位核内,与相应的靶基因启动子结合,控制目的蛋白的表达,对机体的调控起着重要作用。     

miRNA与毛囊相关信号通路关系研究进展

毛囊是哺乳动物皮肤中复杂的微小器官,具有明显的生长周期,包括生长期、退行期和休止期。许多细胞因子和信号通路相互作用共同调节毛囊的发育。微小RNA(micro RNA,miRNA)是由22个核苷酸组成的非编码RNA,通过降解靶基因mRNA或抑制靶基因mRNA翻译来负向调节基因的表达。miRNA通过调控毛囊关键的信号通路,参与细胞增殖、凋亡等多种生理过程,从而促进毛囊生长。笔者综述了miRNA调控毛囊发育相关的Wnt、Notch、骨形态发生蛋白(bone morphogenetic protein, BMP)、丝裂原活化蛋白激酶(mitogen-activated protein kinase, MAPK)信号通路的最新研究进展,旨在为后续探索动物毛囊发育相关的miRNA调控机制提供理论基础。     

mTOR对信号通路调控的研究进展

哺乳动物雷帕霉素靶蛋白(mTOR)信号通路是最近新出现的细胞内重要信号途径,该途径在进化上高度保守,主要通过PI3K/Akt/mTOR信号通路磷酸化激活来调控细胞分裂、促进转录、信号翻译等,从而控制蛋白合成来调节细胞生长。mTOR作为一种重要的调节基因通过调节细胞周期、蛋白质合成、细胞能量代谢等多种途径发挥重要的生理功能,在细胞增殖、生长、分化过程中起着中心调控点的作用。     

黄酮类化合物对免疫相关信号通路的调控作用研究进展

黄酮类化合物具有抗氧化、抗炎、保护心血管、降压、抗菌、抗病毒和抗肿瘤等多种生物活性和药理作用。近年来,黄酮类化合物的免疫调节作用也引起了相关研究人员的重视,论文就黄酮类化合物对免疫相关信号通路(NF-κB信号通路、Toll样受体和JAK-STAT信号通路等)的调控作用进行总结和归纳,以期为揭示黄酮类化合物的免疫调节作用机制研究提供参考。     

PI3K/Akt信号通路对卵泡发育和卵母细胞成熟作用的研究进展

磷脂酰肌醇-3-激酶/蛋白激酶B(PI3K/Akt)是生物体内生长发育过程中的重要信号通路,该通路由多种效应因子组成,在细胞增殖、细胞凋亡、细胞周期、DNA修复和蛋白质合成过程中起关键作用.本文综述了PI3K/Akt信号通路在卵泡发育和卵母细胞成熟方面的研究进展,为相关研究提供理论依据.     

WNT信号通路的研究进展

Wnt(wingless-type MMTV integration site family members)信号通路与细胞的发育分化密切相关,对正常和肿瘤细胞生长都至关重要,因其启动蛋白为Wnt蛋白而得名。本文综述了Wnt蛋白家族、Wnt信号通路、Wnt信号通路与疾病的关系以及WNT信号通路的研究进展,并对家族中一些成员的研究进行了展望。     

整合素通过PI3K/Akt信号通路调控畜禽骨骼健康的研究进展

骨骼是脊椎动物中坚硬的结缔组织,具有构成机体基本支架、保护脏器、支撑体重和维持运动的作用。骨骼发育主要是通过膜内成骨和软骨内骨化完成的,该过程由多种调控因子组成的复杂调控网络共同发挥作用以维持畜禽骨骼健康。整合素（integrin）是细胞膜上的一种介导细胞-基质相互作用的跨膜受体,不仅具有引起细胞黏附的作用,还能够通过双向传递细胞内外的信号引发机体相应反应。整合素能够调控多条信号通路,包括磷脂酰肌醇3-激酶/蛋白激酶B (phosphatidylinositol 3-kinase/protein kinase B,PI3K/Akt)信号通路,在维持畜禽动物骨骼健康方面发挥重要作用。PI3K/Akt信号通路是由酶联受体介导的能够调节细胞生命活动的信号通路,能通过炎症、自噬、凋亡等作用调节软骨代谢平衡,对维持骨骼健康具有重要意义。综合国内外关于畜禽骨代谢、整合素和PI3K/Akt信号通路之间关系的研究进展,从整合素对畜禽骨代谢的影响、PI3K/Akt信号通路对畜禽骨代谢的影响以及整合素通过PI3K/Akt信号通路对骨代谢的影响三方面进行综述,以期为探究整合素通过PI3K/Akt信号通路在畜...     

TOR信号通路的研究进展

TOR信号通路是一种重要的细胞代谢调节通路,可以通过感知营养状态来调节细胞生长、增殖和代谢等过程。使用营养的手段调节TOR信号通路是当前研究的热点。文章综述了TOR信号通路的激活方式及其在畜禽中对生长发育、免疫调节、繁殖和饲料营养等方面的研究进展,研究TOR信号通路的特点和调节机制,为畜禽产业的发展提供参考。     

Comparative study on hypocholesterolemic effect of Rhodopseudomonas palustris and Rhodobacter capsulatus on rats fed a high cholesterol diet

This comparative study was to investigate the hypocholesterolemic effects of dietary Rhodopseudomonas palustris and Rhodobacter capsulatus on rats fed a high cholesterol diet. Thirty male Wister–Imamichi rats were assigned to three groups and fed on either a high cholesterol diet, or a high cholesterol diet supplemented with 2.0% R. palustris or R. capsulatus for 4 weeks. Compared to the control diet, both of the R. palustris and R. capsulatus supplemented diets significantly reduced the serum cholesterol, triglycerides, low‐density lipoprotein, very low density lipoprotein cholesterol and hepatic triglycerides, but increased hepatic cholesterol in rats. In addition, both of the R. palustris and R. capsulatus supplemented diets may reduce the risk of atherosclerosis, as the ratio of high density lipoprotein cholesterol to the total cholesterol was significantly higher than in the control group (P < 0.05). Both the R. palustris and R. capsulatus supplemented diets led to an increase in the serum palmitic acid, compared with the oleic acid and linoleic acid. No significant differences were postulated between the rats fed R. palustris and R. capsulatus supplemented diets during the 4 weeks of the experimental period. Thus, the results may suggest that both R. palustris and R. capsulatus can contribute significant health benefits and seems to be feasible to investigate in future research.     

Calcium metabolism of pregnant rats fed a vitamin D-depleted diet

The effects of vitamin D (VD) deficiency on calcium (Ca) metabolism during pregnancy were evaluated in rats fed VD-repleted (VD-repleted rats) and VD-depleted (VD-depleted rats) diets. In the VD-depleted rats, the plasma concentrations of 1,25-dihydroxyvitamin D and Ca decreased severely, whereas the parathyroid hormone concentrations increased. The Ca contents of the feces of the VD-depleted rats were higher than those of the VD-repleted rats. The fetal Ca contents of the VD-repleted and VD-depleted rats increased continuously, but that of the VD-depleted rats was lower. These data reveal that VD deficiency during pregnancy induces severe hypocalcemia due to reduced intestinal absorption of Ca and elevated fetal demand for Ca.     

l-carnitine supplementation and lipid metabolism of rats fed a hyperlipidaemic diet

Until now, there has been no clear knowledge about the effect of dietary carnitine supplementation on lipid metabolism. Therefore, this study was conducted to investigate the effect of a dietary l -carnitine supplementation (500 mg/kg) onx the lipid metabolism of adult rats. Rats fed a hyperlipidaemic basal diet containing 15% lard and 1% cholesterol were used as an animal model. The feeding period was 6 weeks. As parameters of lipid metabolism, the concentrations of individual lipids in plasma, lipoproteins and liver and the fatty acid composition of liver and erythrocyte total lipids were determined. There were no significant differences between the control group and the group receiving the diet supplemented with carnitine on parameters of animal performance (daily body weight gains and feed conversion ratio). As expected, plasma, very low-density lipoproteins (VLDL) and liver exhibited high concentrations of cholesterol. Concentrations of triglycerides and phospholipids in plasma and individual lipoproteins as well as the concentrations of triglycerides, cholesterol and phospholipids in the liver were not significantly altered by dietary carnitine supplementation. The concentration of cholesterol in plasma and liver was increased by dietary carnitine. The fatty acid composition of liver and erythrocyte total lipids was not influenced by dietary carnitine supplementation. In conclusion, this study does not indicate a lipid-lowering effect of dietary carnitine supplementation in hyperlipidaemic rats. Probably, the essential functions of carnitine in metabolism were realized by carnitine which was synthesized endogenously.     

Protective effects of polyphenol‐rich blackcurrant preparation on biochemical and metabolic biomarkers of rats fed a diet high in fructose

The purpose of the study was to compare in vivo effects of dietary supplementation with blackcurrant pomaces containing variable level of phenolic compounds on blood and internal organ parameters in rats. Forty‐eight growing Wistar rats were allocated to six treatment groups in which they were fed ad libitum for 4 weeks the following diets: standard chow (group S), high‐fructose diet (group F), standard chow supplemented with 7.7% of either rich in polyphenols unprocessed blackcurrant pomace (UB) or polyphenol‐deprived processed pomace (PB) (groups SUB and SPB respectively), and high‐fructose diet with 7.7% of either UB or PB (groups FUB and FPB respectively). Blackcurrant pomace, irrespective of its phenolic content, selectively modulated the enzymatic activity of the colon microflora, reducing the activity of enzymes with potentially harmful properties and promoting activities of enzymes that might increase the use of carbohydrates that escaped digestion in the upper gastrointestinal tract. Although both pomaces increased antioxidant status of the liver and blood serum, the unprocessed pomace showed a greater ability to inhibit lipid peroxidation in heart and kidney than the pomace that was less abundant in polyphenols. Both of the examined pomaces had a positive influence on serum lipid profile, but better hypocholesterolemic effect was observed after supplementation of the diet with unprocessed preparation. The biochemical action of unprocessed pomace in the normalization of fructose‐induced disturbances was more distinct than those of pomace remaining after extraction.     

藤黄果提取物对高脂日粮诱导的大鼠部分组织中氨基酸谱的影响

为探讨藤黄果提取(-)-羟基柠檬酸(HCA)对高脂日粮诱导的大鼠部分组织器官中氨基酸谱的影响,选用100只雄性SD大鼠随机分成5组:普通日粮对照组,高脂日粮对照组,高脂日粮添加藤黄果提取物低剂量组、中剂量组和高剂量组,每组20只。高脂日粮组分别于日粮中添加相当于(-)-HCA的剂量为0,1 000,2 000和3 000 mg/kg的藤黄果提取物,饲养8周后采集静脉血,分离血清,取肝脏、腿肌等样品。试验结果表明:与普通日粮对照组比较,高脂日粮对照组中,大鼠体增重和BMI均极显著升高(P0.01)。与高脂日粮对照组比较,3个剂量的藤黄果提取物处理均可极显著降低大鼠的体增重(P0.01);低剂量组中肝糖原含量显著升高(P0.05),高剂量组肌糖原含量显著升高(P0.05),但对血糖浓度无显著性影响(P0.05);血清中T3和T4含量在高剂量处理组均显著升高(P0.05),血清瘦素含量在低剂量组显著升高(P0.05),而血清中胰岛素的含量则无显著变化(P0.05)。氨基酸组成分析结果表明:在血清中,藤黄果提取物处可以显著升高血清中部分生糖氨基酸的含量,支链氨基酸中异亮氨酸(Ile)及芳香族氨基酸色氨酸(Trp)的含量(P0.05);在肝脏中,藤黄果提取物可以显著降低肝脏组织中大部分生糖氨基酸和芳香族氨基酸的含量(P0.05),而对肝脏中支链氨基酸的影响不显著(P0.05);在腿肌中,(-)-HCA处理可显著降低生糖氨基酸的含量(P0.05),可以极显著降低支链氨基酸的含量(P0.01),同时(-)-HCA可以极显著降低芳香族氨基酸的含量(P0.01)。以上结果表明,藤黄果提取物通过改变大鼠血清中激素的含量、降低肝脏和肌肉中生糖氨基酸的含量,提高机体糖代谢的水平,达到抑制大鼠体重增加的效果。     

The effect of an oxidized dietary oil on plasma cholesterol and thyroid hormone concentrations in miniature pigs fed on a hyperlipidaemic diet

Introduction Polyunsaturated fatty acids (PUFA) are labile compounds which under the promoting effect of oxygen, high temperature or metallic catalysts undergo peroxidative damage. In the course of lipid peroxidation, several primary and secondary products such as peroxides, aldehydes, dimers or polymers are formed. Human western diets are not only generally rich in fats, but also rich in fats that have been subjected to various degrees of processing and heat treatment, particular deep fat frying. The absolute intake of lipid peroxidation products in western countries varies over a wide range, depending on the individual eating habits; however, it can be assumed that on average of the population at least 50% of the fat consumed has been heated during industrial processing of foods or preparing of meals. Therefore, the potential toxic effects of products formed from polyunsaturated fatty acids during heating or frying of fats are of particular interest for human health, particularly in the development of coronary heart disease. In literature, there is one study which reports that the development of atherosclerosis is accelerated by dietary oxidized lipids in cholesterol-fed rabbits (S trapans et al. 1996). The reason for this observation, however, is not clear. The pathogenesis of atherosclerosis is very complex. Undoubtedly, the concentration of cholesterol in plasma and in lipoproteins as well as the susceptibility of low-density lipoproteins to lipid peroxidation are major factors influencing the risk of coronary heart disease (S teinberg et al. 1989; M archioli et al. 1996). In order to clarify a potential relationship between the intake of dietary oxidized lipids and an increased risk of coronary heart disease, this study investigated the effects of feeding oxidized oils on the concentrations of lipids in plasma and lipoproteins and the susceptibility of plasma lipids to peroxidation (S taels et al. 1990; T anis et al. 1996). The concentrations of thyroid hormones in plasma were measured because they are in close relationship with the plasma cholesterol concentration. Miniature pigs that were fed a cholesterol-enriched diet were used in this study because they have been described to be an adequate model for the investigation of the lipid metabolism in humans (B arth et al. 1990). A general problem in the investigation of the effects of dietary oxidized lipids is that the administration of a diet containing highly oxidized fats reduces food intake, food efficiency and the digestibility of fatty acids (C orcos benedetti et al. 1987; Y oshida and K ajimoto 1989; B lanc et al. 1992; H ayam et al. 1993; B orsting et al. 1994; L iu and H uang 1996; H ochgraf et al. 1997). Moreover, because of strong oxidation, highly oxidized oils usually contain significantly less PUFA and tocopherols than the equivalent fresh oils (D& rsquo ; aquino et al. 1985; C orcos benedetti et al. 1987; B lanc et al. 1992; B orsting et al. 1994; H ayam et al. 1995; L iu and H uang 1995; H ochgraf et al. 1997). In order to avoid these problems a controlled feeding system was used in this study and dietary fats were equalized for their fatty acid composition and tocopherol concentrations. Studies from literature reported that dietary oxidized oils reduce tocopherol concentrations and thereby alter the fatty acid composition of tissues and increase the fragility of erythrocyte membranes in animals (C orcos B enedetti et al. 1987; Y oshida and K ajimoto 1989; B lanc et al. 1992; H ayam et al. 1993). However, as mentioned above, in most of the studies reported in literature, the concentration of vitamin E was significantly lower in diets containing oxidized oils than in control diets. In order to find out whether those effects are also observed if diets are adjusted for identical vitamin E activities, this study also measured the tocopherol concentration in plasma, the fatty acid composition of erythrocyte lipids and the osmotic fragility of erythrocytes.     

Effect of capsaicin on cholecystokinin and neuropeptide Y expressions in the brain of high-fat diet fed rats

Capsaicin, one of the pungent principles of hot pepper, has been reported to cause a cessation of increases in body weight and fat gain induced by high-fat feeding. Especially, in body weight and feeding control, cholecystokinin (CCK) has been well known as a satiety signal and neuropeptide Y (NPY) has been described as one of the most potent orexigenic signals. This study was carried out to investigate the effect of capsaicin on CCK- and NPY- immunoreactivities (IR) in the brain of high-fat fed rats. The animals were divided into normal-fat diet (NF), high-fat diet (HF) and high-fat diet containing capsaicin (HF-CAP) groups. Mean body weight gain (MBWG) of HF group was higher than that of NF group. However, in HF-CAP group, MBWG was lower than that of HF group. CCK-IR in suprachiasmatic nucleus (SCN), paraventricular nucleus (PVN), median eminence (ME), arcuate nucleus (ARC) and amygdala was not prominent in all the groups. In cerebral cortex, CCK-IR was more reduced in HF-CAP group than in the other groups. In the HF-CAP group, NPY-IR in the hypothalamic nuclei, amygdala and cerebral cortex was more poorly found than in the NF and HF groups. It is concluded that (1) NPY-IR may react more sensitively on capsaicin than CCK-IR, (2) no rapid increase of body weight in capsaicin treated rats may result from the diminished food intake through the low expression of NPY in hypothalamus in HF-CAP group.     

The effects of exogenous xylanase supplementation on the in vivo generation of xylooligosaccharides and monosaccharides in broilers fed a wheat-based diet

ABSTRACT

1. This study quantified xylanase-induced changes in soluble monosaccharides, xylooligosaccharides (XOS) and volatile fatty acid (VFA) contents of the different sections of the gastrointestinal tract (GIT) and whether these were related to altered bird performance.

2. An in vitro digestion of the wheat-based diet was carried out with the xylanase (Econase XT at 16,000BXU/kg diet) to compare the in vitro and in vivo generation of these XOS and monosaccharides. For the in vivo study, 80 male Ross 508 b roiler chicks were split into two groups fed a wheat-based diet with or without Econase XT (16,000BXU/kg diet) for 21 days.

3. There were no effects of Econase XT inclusion on growth performance characteristics, likely a result of the high-quality wheat diet, the corresponding high performance of the control group (FCR average of 1.45 in controls) and the relatively young age of the birds (from four to 26 days of age).

4. Econase XT supplementation increased the xylotetraose (X₄) content in the colon (P = 0.046, enzyme x GIT section interaction) and the xylose contents in the colon and caeca (P < 0.001, enzyme x GIT section interaction).

5. The trend for increased acetate production in the caeca of Econase XT treated birds (P = 0.062) suggested that the XOS generated were subsequently fermented in the caeca, potentially impacting upon the types of microbiota present.

6. The present study suggested that wheat arabinoxylan degradation was enhanced by xylanase supplementation, which may have increased the production of beneficial volatile fatty acids (VFA) in the caeca, and thereby potentially modulated the caecal microbiome, but without affecting bird performance at this early age.     

Studies on nitrogen metabolism in rats of different age fed on a protein-free diet. 2. The feed intake

Changes in the intake of dry matter (DM) of the protein-free diet (PFD) fed ad libitum were studied on male rats in relation to the shrunk body mass (SB) and duration of protein-free feeding (t). The intake of DM and changes of SB were investigated on the same rats and during the same experimental periods. The mean intake of DM in relation to PFD feeding periods t = 3, 6, 9, 12, 16 days and the daily DM intake (DMd) in relation to the daily shrunk body mass (SBd) were calculated on logarithmical values according to a model of linear regression y = a + bx and to a model of multiple regression y = b0 + b1x1 + b2x2. The rate of DM intake in relation to the duration of PFD feeding (t) did not differ significantly between age groups (k = 14) but the ak differed significantly. The common coefficient bc = 0.871 +/- 0.012 was less than 1***. This relationship is described by the equation: DM intake = Ak X t0.871, where: DM intake = the sum of intake in the periods of 3, 6, 9, 12 and 16 days (in grams), k = age group, t = PFD feeding period. No significant correlation (P less than 0.05) was found between bk and the initial body mass (SBi) or age of rats (r = -0.21 and -0.02, respectively) but between ak and SBi or age the correlation was highly significant (r = 0.960 and 0.832). This indicates that the amount but not the rate of DM intake depended on the initial body mass or age. The relation between DMd and SBd, the latter increasing with age but decreasing with the duration of PFD feeding, is described by equation: DMd intake = Ad X SBd0.503, where: DMd intake in grams, d = day 1 to 15 of PFD feeding, SBd = daily shrunk body mass in kilograms. The values of Ad decreased with the duration of PFD feeding. The using of multiple regression permitted to describe DMd intake as a function of SBd and (d) by a common equation: DMd intake = 27.02 X SBd0.503 X d-0.103; R = 0.976. Thus the daily DM intake was closely positively correlated with SBd and negatively correlated with the duration of protein-free feeding regardless of the age of rats.(ABSTRACT TRUNCATED AT 400 WORDS)