RNA干扰低分子重量蛋白2基因对脑缺血大鼠血脑屏障的影响

目的观察RNA干扰免疫蛋白酶体亚基低分子重量蛋白2(LMP2)对脑缺血再灌注大鼠血脑屏障结构相关蛋白闭合蛋白(Occludin)和闭锁小带蛋白(ZO^(-1))表达的影响。方法线栓法制作SD大鼠大脑中动脉阻塞再灌注(MCAO)模型,脑缺血1 h再灌注72 h。按照体重将SD大鼠随机分为3组:假手术组、实验组和对照组,每组10只。在MCAO术前1 h,实验组和对照组分别立体定位地脑内注射慢病毒载体LMP2-shRNA和阴性对照shRNA液体。以免疫印迹法分析Occludin、ZO^(-1)蛋白表达,用伊文思蓝(EB)示踪法监测血脑屏障损伤程度。结果 Occludin蛋白与ZO^(-1)蛋白的灰度值:假手术组、对照组和实验组分别1.76±0.09,1.37±0.12;0.24±0.07,0.26±0.07;0.83±0.11,0.74±0.09,与假手术组比较,对照组差异均有统计学意义(均P<0.001);与对照组比较,实验组差异也均有统计学意义(均P<0.001)。脑组织EB含量:假手术组、对照组和实验组分别(3.32±0.14),(11.41±0.21),(6.23±0.28)μg·g^(-1),与假手术组比较,对照组差异有统计学意义(P<0.001);与对照组比较,实验组差异也有统计学意义(P<0.001)。结论沉默LMP2基因表达可显著改善大鼠脑缺血后血脑屏障透通性。

双黄蛋是激素催出来的吗?

现在市售鸡蛋有养殖鸡蛋和笨鸡蛋,也有部分标注＂双黄蛋＂。双黄蛋在以前非常少见,在生活中偶尔吃到双黄蛋,还会有一种＂中奖＂的感觉。也有信息称双黄蛋是非正常培育,含有激素,尤其少年儿童不宜吃,吃了会影响发育。那么双黄蛋究竟是什么呢？

A Novel Hydrolytic Product from Flesh of Mactra veneriformis and Its Bioactivities in Calcium Supplement

To prepare calcium-binding peptides, the flesh residue of Mactra Veneriformis was subjected to enzymatic hydrolysis. By comparing the capability of combining calcium of the hydrolyzates, pepsin was confirmed to be the most suitable enzyme for hydrolyzing the flesh residue to release calcium-binding peptides among the seven tested proteases. The pepsin hydrolyzate (PHM) was divided into three fractions according to the molecule weight of its composition, which ranged from 0.5 to 15 kDa. The low-molecule-weight fraction named PHM-3 had the highest capability in combining calcium. The peptides existing in the PHM-3 fraction consisted of higher contents of Glu, Ala and Leu, and could produce one type of calcium-peptide complex by powerfully chelating calcium ions. PHM-3 products could effectively increase calcium absorption and retention while they decreased the calcium excretion in animal tests. Additionally, symptoms caused by low calcium bioavailability in ovariectomized rats, such as bone mineral density reduction and mechanical strength loss could be significantly ameliorated by the hydrolytic products addition in diet.

Diagnostic and therapeutic implications of the association between ferritin level and severity of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease(NAFLD),defined by excessive liver fat deposition related to the metabolic syndrome,is a leading cause of progressive liver disease,for which accurate non-invasive staging systems and effective treatments are still lacking.Evidence has shown that increased ferritin levels are associated with the metabolic insulin resistance syndrome,and higher hepatic iron and fat content.Hyperferritinemia and iron stores have been associated with the severity of liver damage in NAFLD,and iron depletion reduced insulin resistance and liver enzymes.Recently,Kowdley et al demonstrated in a multicenter study in 628 adult patients with NAFLD from the NAFLD-clinical research network database with central re-evaluation of liver histology and iron staining that the increased serum ferritin level is an independent predictor of liver damage in patients with NAFLD,and is useful to identify NAFLD patients at risk of non-alcoholic steatohepatitis and advanced fibrosis.These data indicate that incorporation of serum ferritin level may improve the performance of noninvasive scoring of liver damage in patients with NAFLD,and that iron depletion still represents an attractive therapeutic target to prevent the progression of liver damage in these patients.

Assessment of nitrogen maintenance requirement in juvenile Black Porgy Acanthopagrus schlegeli

Nitrogen balance method and nitrogen-free diet were used in this study to determine nitrogen maintenance requirement (NM) and nitrogen maintenance requirement per unit metabolism body weight (NM’) of black porgy Acanthopagrus schlegeli. Fish with body weight (BW) of 50, 80, 120, 160 and 200 g were fed by the diets containing three graded levels of crude protein (380, 420 and 460 g/kg). The results from nitrogen balance experiment showed that the amount of nitrogen deposition varied from 0.15 to 0.31 mg/g BW per day, accounting for 12.2% to 21.1% of nitrogen intake. The amount of fecal nitrogen excretion varied from 0.21 to 0.32 mg/g BW per day, accounting for 16.3% to 21.6% of nitrogen intake. The endogenous nitrogen excretion, a main part of nitrogen consumption varied from 0.79 to 0.97 mg/g BW per day, accounting for 63.3 % to 68.0% of nitrogen intake. Positive correlation was found between NM and body weight, while a negative correlation was found between NM of unit body weight and the growth duration. No significant differences (p>0.05) were found in NM’ among different growth stages. The average of NM’ was 0.485 7mg/g per day. The results from nitrogen-free diet experiment showed that a negative correlation between NM and feed intake of nitrogen-free diet. NM increased with the decrease of feed intake of fish. The average of NM was 0.482 9 mg/g BW per day that was close to 0.483 8 mg/g BW obtained from fish with 120 g BW in nitrogen balance experiment. The nitrogen balance method is recommended to be a better method for determining NM in consideration of fish stress and result stability. This study also provides a calculated result of the protein content in diets, which is necessary for maintaining fish body protein at different growth stages. The calculation was based on the amount of nitrogen required for maintaining body protein per kg BW.

Research on the Construction and Function of a Chlorophyll Degradation Recombinant Engineering Strain

In order to effectively reduce the chlorophyll content in flue-cured tobacco, improve the overall quality of tobacco leaves, chlorophyllase gene was cloned from Arabidopsis thaliana. After the expression of the expression vector in E. coil, the recombinant engineering strain was obtained. Afterwards, IPTG （isopropy-β-D-thiogalactopyranoside）was used to induce the goal protein, and the chlorophyllase activity of the recombinant engineering strain was measured, so as to investigate its degradation effect on the chlorophyll in the extracts of tobacco leaves. The results were as follows： （1） the amplified chlorophyllase gene At- CLH1 constructed the expression vector pET28a-AtCLH1 successfully, obtaining the recombinant engineering strain; （2） induced under 30 ℃ for 22 h, the strain could well express the recombinant protein AtCLH1 with 0.5 mmol/L IPTG, and the molecular weight was about 35 kDa; （3） the strain showed good chlorophyllase producing capability, and the activity of the produced chlorophyllase could reach up to 24.9 U/mL, which could degrade the chlorophyll in tobacco extract and had a good application prospect in improving the quality of low quality tobacco; （4） based on the results of orthogonal test, the enzyme extract from the strain was added to the tobacco leaf surface, which could make the degradation rate of chlorophyll in the tobacco leaf reach 17.06% under the temperature of 37 ℃ at the humidity of 75% for 48 h; （5） after treated by the enzyme liquid, the test tobacco showed increase in the content of aromatic substances, enhancement of tobacco fragrance quality and amount, significant decrease of offensive odor and irritation, significant improvement of agreeable aftertaste, making the overall sensory quality of the tobacco leaf significantly improved.

Exploration of Urinary Creatinine to Determine the Carcass and Its Protein Weight in Beef Cattle

This study was aimed to explore the use of creatinine as indicator to predict carcass and its protein weight in beef cattle. Eight Ongole crossbred cattle with initial body weight ranged at 133.5-228 kg and age of 6-18 months were used in this study. The cattle were fed Napier grass ad libitum and concentrate feeding for three months prior to be slaughtered. Concentrate feeding was consisted of rice bran and soybean meal which was provided to fulfill dry matter requirement at 2.1% of body weight （BW）. The availability of creatinine for prediction indicator was done by evaluate the correlation between the amount of daily urinary creatinine and the carcass and its protein weight. Carcass and its protein weight were measured by slaughtering the cattle, and chemically analyzed for determining protein content of carcass. The results showed that creatinine excreted in urine have a strong correlation with the cattle body weight （r = 0.88）, carcass weight （r = 0.67）, body protein （r = 0.70） and carcass protein （r = 0.72）. The conclusion of this study is creatinine excreted in urine have a strong relationship with the carcass and its protein, and therefore could be used to predict the carcass and its protein weight of beef cattle.

INTRODUCTION OF THE HIGH THROUGHPUT SCREENING SYSTEM

In this article, we introduce the system of high throughput screening (HTS). Its role in new drug study and current development is described. The relationship between research achievements of genome study and new type screening model of new drugs is emphasized. The personal opinions of current problems about HTS study in China are raised.

Effect of High Digestible Essential Amino Acids on Weight Gains and Carcass Compositions of Laying Hens

The objective of this study was to evaluate the effect of high digestible essential amino acids （DEAA） on weight gains and carcass compositions of laying hens. Three hundred and sixty lsa Brown hens in five replications per treatment （12 birds/replicate） were used. Six experimental diets which contained of treatment 1 （negative control） as the conventional layer diet are recommended by NRC （1994） while another dietary treatments; treatments 2 （positive control）, 3, 4, 5 and 6 were formulated to meet 100%, 110%, 120%, 130% and 140% of Standard Ileal Digestible Lysine Levels （SIDLL） without crude protein minimum, while methionine （Met）, threonine （Thre） and tryptophan （Tryp） as related by Ideal Protein Concept （IPC） which suggested by NRC （1994） and INRA （2004）. However, metabolizable energy （ME）, calcium and available phosphorus （Avai P） levels of all experimental diets were meet requirement as recommended by NRC （1994）. The experiment was assigned in CRD and laying hens fed dietary treatments from 28 to 44 weeks of age and cage was the experimental unit （3 hens/cage）. The result shown that percentages of thigh （TP）, feet （FP）, drumstick （DP）, heart （HP）, liver （LP） and gizzard （GP） were not affected by dietary treatment. However, weight gains （WG） and percentage of dressed weight （DWP）, eviscerate weight （EWP） and breast （BP） were increased （P 〈 0.05） and abdominal fat was reduced （P 〈 0.05） when birds fad diets containing 130% of SIDLL as compared with control group and another dietary treatments, when increasing the DEAA levels upper to 130% of SIDLL. The result indicated that diets formulated without crude protein minimum and increased DEAA resulted in increasing the efficiency of converting metabolizable energy （ME） to net energy （NE） for increasing weight gain and improved meat products while fat deposition in carcass composition was reduced.

Relationship between Seed Yield and Yield Chracteristics in Faba Bean （Vicia faba L.） by GGE-Biplot Analysis

Viciafaba L. was domesticated around 8000 BC in the Near East; the crop spread to Central Europe and Russia through Anatolia, the Danube Valley and the Caucasus; to Eastern Mediterranean regions through the Mediterranean coast and the Isles; from Egypt and Arabian Coast （the Arabia Felix） to Abyssinia; through Mesopotamia to India and China probably during the first millennium AD （only land races of major type, the latest in being produced, were known in China until recently）. Faba bean （Vicia faba L.） is grown world-wide as a protein source for food and feed. The importance of nutzients （micro and macro） for human growth is universally recognized. An investigation was camed out to select the most successful faba bean genotypes to estimate for seed yield and some of agro-morphological traits. Effective interpretation of the dataon breeding programes is important at all stages of plant improvment. The GT （genotype by trait） was used for two-way faba bean genotypes with multiple traits. For this purpose, six faba bean genotypes with specific components were tested and the GT biplot for genotype data explained 83% of total variation of the standardized data. The polygon view of GT presented for five traits of faba bean genotypes showed three vertex genotypes as Goryaka, Karcacaoglan and Seher. Genotype G0ryaka had the highest values for most of the traits. It was demonstzaited that the selection of high seed yield will be via hundred seed weight and planth height. These traits should be considered meanwhile as effective selection criteria developing high yielding faba bean genotypes because of their large contibution to grain yield. The genotypes Goryaka and Karacaoglan could be well-considered for improving of desirable candidate in selection of improvement studies.