灵芝孢子油对免疫低下小鼠免疫调节机制的初步研究

目的采用免疫功能低下小鼠模型探讨灵芝孢子油免疫调节作用机制。方法将昆明小鼠随机分成模型对照组、灵芝孢子油组、正常对照组,每组10只;模型对照组、灵芝孢子油组分别腹腔注射40mg.kg-1.-1)环磷酰胺建立免疫功能低下小鼠模型,正常对照组腹腔注射生理盐水(0.9%)0.1ml/10g BW;同时灵芝孢子油组150mg/kg,正常和模型对照组灌胃玉米油0.1ml/10g BW,灌胃1次/A,连续30d;用ELISA试剂盒检测小鼠血清TNF-α、IFN-$水平,半定量PCR检测小鼠脾脏、胸腺IL-2、IL-10、IL-12、IL-4、IFN-$、TNF-α基因表达量,初步探讨灵芝孢子油的免疫调节机制。结果灵芝孢子油明显提高环磷酰胺免疫低下模型小鼠血清中TNF-α、IFN-$的含量,脾脏和胸腺中IL-2、IL-10、IL-12、IL-4、TNF-α和IFN-$mRNA的表达量,与模型对照组间差异显著(P≤0.05)。结论灵芝孢子油通过增强细胞因子的分泌、表达进行免疫调节。     

Induction of a protective immune response to rabies virus in sheep after oral immunization with transgenic maize, expressing the rabies virus glycoprotein

The introduction of exogenous genes into plants permits the development of a new generation of biological products, i.e., edible vaccines. Cereals, especially maize, have been the systems of choice for the expression of antigenic proteins because the proteins can be expressed at high levels in the kernel and stored for prolonged periods without excessive deterioration. The utilization of plant-derived antigens for oral delivery provides an alternative strategy for the control of pathogens in animals compared to the current vaccine administration methods, such as injection. However, there is some doubt about the efficacy of these types of vaccines in polygastric animals due to the features of their digestive system. Here, we report the efficacy of an edible vaccine against rabies evaluated in sheep. Kernels containing different doses of G protein (0.5, 1, 1.5 and 2mg) were given in a single dose by the oral route. Cumulative survival was better in groups that received 2mg of G protein and for the positive control (inactivated rabies vaccine); this observation was supported by the presence of neutralizing antibodies. Animals in the control group died after challenge. The degree of protection achieved for 2mg of G protein was comparable to that conferred by a commercial vaccine. In conclusion, this is the first study in which an orally administered edible vaccine showed efficacy in a polygastric model.     

淀粉微球的制备及性能试验

以玉米淀粉为原料，环氧氯丙烷为交联剂，采用逆相悬浮交联聚合法合成了淀粉微球。电镜扫描显示，微球为圆形，表面粗糙，以酮洛芬为模型药物，微球吸附载药量为140mg／g。     

Mutagenicity of municipal water obtained from an agricultural area

We have studied the mutagenicity of the water from Lake Bloomington and of the tap water that is made from the lake water. The lake, which is the source of drinking water for Bloomington, Illinois (pop. 44,000), is surrounded by land that is farmed intensively - being mainly in maize and soybeans. Samples were collected monthly from May through October 1979 and concentrated 3,000× with XAD-2 resin. Nearly all of the lake and tap water concentrates were mutagenic in Salmonella typhimurium TA98 and TA100 in the presence of S-9 mix, and the May tap water concentrate was highly mutagenic. In addition, many of the concentrates were toxic to the bacteria in the absence of S-9 mix. Chemical analysis of the highly mutagenic tap water concentrate from May revealed the presence of a number of organic contaminants that were absent from control concentrates prepared from deionized and distilled treated well water. In addition, unconcentrated lake and tap water were tested in a reverse-mutation test in maize (Zea mays); no mutagenicity was detected. This study indicates that the contamination of drinking water with agricultural and/or industrial chemicals may result in a potential health hazard.     

Discovery and characterization of proteins associated with aflatoxin-resistance: evaluating their potential as breeding markers

Host resistance has become a viable approach to eliminating aflatoxin contamination of maize since the discovery of several maize lines with natural resistance. However, to derive commercial benefit from this resistance and develop lines that can aid growers, markers need to be identified to facilitate the transfer of resistance into commercially useful genetic backgrounds without transfer of unwanted traits. To accomplish this, research efforts have focused on the identification of kernel resistance-associated proteins (RAPs) including the employment of comparative proteomics to investigate closely-related maize lines that vary in aflatoxin accumulation. RAPs have been identified and several further characterized through physiological and biochemical investigations to determine their causal role in resistance and, therefore, their suitability as breeding markers. Three RAPs, a 14 kDa trypsin inhibitor, pathogenesis-related protein 10 and glyoxalase I are being investigated using RNAi gene silencing and plant transformation. Several resistant lines have been subjected to QTL mapping to identify loci associated with the aflatoxin-resistance phenotype. Results of proteome and characterization studies are discussed.     

复方玉米幼芽提取物霜剂的制备及其对皮肤的安全性研究

目的:制备一种以玉米幼芽提取物(extracts of maize plumule,EMP)为主药的外用抗衰老透皮制剂(O/W),并对其应用于皮肤的安全性进行评价。方法:选用合适的表面活性剂,利用乳化法制备O/W型EMP霜剂;根据《化妆品卫生规范》(2007版)中毒理学试验方法以及人体贴斑试验考察其安全性。结果:制备的EMP霜剂体系均一稳定,对皮肤无毒性、刺激性、过敏性和光毒性。结论:EMP作为一种新型的抗氧化剂,具有良好的配伍性,可以安全可靠地应用于医药和化妆品工业。     

Comparison of the side-needle and knife techniques for inducing Aspergillus flavus infection and aflatoxin accumulation in corn hybrids

Evaluation of corn genotypes for resistance to aflatoxin accumulation has evolved over the past 30 years. Inoculation techniques have been developed to ensure that plants are exposed to Aspergillus flavus and resistant genotypes can be identified. We compared two inoculation techniques (side needle and knife) and different inoculation rates in Georgia and Mississippi. The relative performance of side-needle and knife inoculation techniques did not change or interact significantly across site years, suggesting that both the needle and knife are consistent inoculation techniques for discriminating between resistant and susceptible corn hybrids at the Mississippi State and Tifton locations.     

Comprehensive assessment of maize aflatoxin levels in Eastern Kenya, 2005-2007

Background: Aflatoxin, a potent fungal toxin, contaminates 25% of crops worldwide. Since 2004, 477 aflatoxin poisonings associated with eating contaminated maize have been documented in Eastern Kenya, with a case-fatality rate of 40%.Objective: We characterized maize aflatoxin contamination during the high-risk season (April–June) after the major harvests in 2005, 2006 (aflatoxicosis outbreak years), and 2007 (a non-outbreak year).Methods: Households were randomly selected each year from the region in Kenya where outbreaks have consistently occurred. At each household, we obtained at least one maize sample (n = 716) for aflatoxin analysis using immunoaffinity methods and administered a questionnaire to determine the source (i.e., homegrown, purchased, or relief) and amount of maize in the household.Results: During the years of outbreaks in 2005 and 2006, 41% and 51% of maize samples, respectively, had aflatoxin levels above the Kenyan regulatory limit of 20 ppb in grains that were for human consumption. In 2007 (non-outbreak year), 16% of samples were above the 20-ppb limit. In addition, geometric mean (GM) aflatoxin levels were significantly higher in 2005 (GM = 12.92, maximum = 48,000 ppb) and 2006 (GM = 26.03, maximum = 24,400 ppb) compared with 2007 (GM = 1.95, maximum = 2,500 ppb) (p-value < 0.001). In all 3 years combined, maize aflatoxin levels were significantly higher in homegrown maize (GM = 17.96) when compared with purchased maize (GM = 3.64) or relief maize (GM = 0.73) (p-value < 0.0001).Conclusions: Aflatoxin contamination is extreme within this region, and homegrown maize is the primary source of contamination. Prevention measures should focus on reducing homegrown maize contamination at the household level to avert future outbreaks.     

Multivariate analysis of maize disease resistances suggests a pleiotropic genetic basis and implicates a GST gene

Plants are attacked by pathogens representing diverse taxonomic groups, such that genes providing multiple disease resistance (MDR) are expected to be under positive selection pressure. To address the hypothesis that naturally occurring allelic variation conditions MDR, we extended the framework of structured association mapping to allow for the analysis of correlated complex traits and the identification of pleiotropic genes. The multivariate analytical approach used here is directly applicable to any species and set of traits exhibiting correlation. From our analysis of a diverse panel of maize inbred lines, we discovered high positive genetic correlations between resistances to three globally threatening fungal diseases. The maize panel studied exhibits rapidly decaying linkage disequilibrium that generally occurs within 1 or 2 kb, which is less than the average length of a maize gene. The positive correlations therefore suggested that functional allelic variation at specific genes for MDR exists in maize. Using a multivariate test statistic, a glutathione S-transferase (GST) gene was found to be associated with modest levels of resistance to all three diseases. Resequencing analysis pinpointed the association to a histidine (basic amino acid) for aspartic acid (acidic amino acid) substitution in the encoded protein domain that defines GST substrate specificity and biochemical activity. The known functions of GSTs suggested that variability in detoxification pathways underlie natural variation in maize MDR.