3组常见马源性成分鉴定引物特异性和灵敏度比较

比较筛选基于聚合酶链式反应(polymerase chain reaction, PCR)技术的马源性成分鉴定方法中高灵敏度和特异性引物。方法 选取来自国标法、专利和文献报道的3组马源性成分鉴定引物, 比较其灵敏度和特异性, 筛选高灵敏度和特异性引物。结果 3组引物的灵敏度和特异性存在差异, 以线粒体DNA为靶标的Ⅱ组马源性成分鉴定引物的特异性和灵敏度优于分别以线粒体和核基因组DNA为靶标的马驴通用鉴定引物, 检出最低限度均满足检测需求。结论 通过比较马源性成分鉴定的3组PCR引物, 以线粒体DNA为靶标的Ⅱ组马源性成分特异性鉴定引物可作为马成分鉴定的首选, 线粒体和核基因组靶标联合可提高马成分鉴定的准确性并可用于杂交种鉴定, 为马源性成分及产制品鉴定提供了一定基础。     

动态口令系统木马攻击能风险分析及防御

动态口令是目前常用于替代静态口令的一种强身份鉴别技术,但骇客人员发现了一种针对动态口令系统的有效木马攻击方法,能够完成针对目前大部分商业动态口令系统的攻击。论文详细分析了该木马的工作原理,并给出了两种针对性的解决方案。     

Reduction of non-digestible oligosaccharides in horse gram and green gram flours using crude α-galactosidase from Streptomyces griseoloalbus

The effectiveness of using crude extracellular α-galactosidase from Streptomyces griseoloalbus for the treatment of horse gram and green gram flours was investigated by comparing with traditional treatments such as soaking and cooking. The enzymatic treatment was most effective and the raffinose content in horse gram flour was reduced by 97.5% and stachyose content by 93.2%. The reduction in the raffinose content of green gram flour was 96.3% and that for stachyose was 91.8%. The information obtained from the present investigation is advantageous for the large-scale production of horse gram flour and green gram flour free of flatulence-causing oligosaccharides.     

Current asthma and respiratory symptoms among pupils in relation to dietary factors and allergens in the school environment

The aim was to study asthma and allergy in relation to diet and the school environment. Pupils (5-14 years) in eight schools received a questionnaire, 1014 participated (68%). Settled dust was collected on ALK-filters and analyzed for allergens from cat (Fel d 1), dog (Can f 1), horse (Equ cx), house dust mites (Der p 1, Der f 1), and cockroach (Bla g 1) by ELISA. In total, 6.8% reported cat allergy, 4.8% dog allergy, 7.7% doctor's diagnosed asthma and 5.9% current asthma, and 7.8% reported wheeze. Current asthma was less common among those consuming more fresh milk (P < 0.05) and fish (P < 0.01). Poly-unsaturated fatty acids was associated with more wheeze (P < 0.05), olive oil was associated with less doctors' diagnosed asthma (P < 0.05). Totally, 74% of the classrooms had mean CO(2) <1000 ppm. The median concentration per gram dust was 860 ng/g Fel d 1, 750 ng/g Can f 1 and 954 U/g Equ cx. Horse allergen was associated with more wheeze (P < 0.05), daytime breathlessness (P < 0.05), current asthma (P < 0.05) and atopic sensitization (P < 0.05). Dog allergen was associated with wheeze (P < 0.05) and daytime breathlessness (P < 0.05). The associations between allergens and respiratory symptoms were more pronounced among those consuming margarine, not consuming butter, and with a low intake of milk. In conclusion, cat, dog and horse allergens in schools could be a risk factor for asthma and atopic sensitization, and dietary factors may interact with the allergen exposure. PRACTICAL IMPLICATIONS: Previous school studies performed by us in mid-Sweden, showed that most classrooms did not fulfill the ventilation standards. In this study, most of the classrooms fulfilled the ventilation standard, but despite that had widespread allergen contamination. Most previous studies have focused on cat allergen, but our study has shown that also dog and horse allergens can be risk factors for asthma and allergy in schools. As allergens are transported from other environments, mainly the home environment, the main prevention should be to minimize transfer of allergens. This could be achieved by reducing contacts with furry pets and horses, or using different clothes at home and at school (e.g. school uniforms). Increased cleaning in the schools may reduce allergen levels, but the efficiency of this measure must be evaluated in further intervention studies. Finally, our study supports the view that dietary habits among pupils should not be neglected and interaction between dietary factors and indoor allergen exposure needs to be further investigated.     

Identification of meat species by TaqMan-based real-time PCR assay

In this study, a convenient, sensitive and specific real-time PCR assay was described for the species identification and their quantification in raw and cooked meat products. Specific primers and TaqMan probes were designed on the mitochondrial ND2, ND5 and ATP 6-8 genes for donkey, pork and horse, respectively, and the performance of the method was tested. In the results, no cross-reaction was observed between the donkey and pork species specific primer-probe systems and non-target species (bovine, ovine, chicken and turkey). Only one cross reaction was observed between the horse species specific primer-probe set and 100 ng pork DNA at the ct 33.01 level (corresponding to 0.01 ng horse DNA). The real-time quantitative assay used in this study allowed the detection of as little as 0.0001 ng template DNA from pure meat for each species investigated and experimental meat mixtures. In conclusion, it can be suggested that the TaqMan probe assay used in this research might be a rapid and sensitive method for the routine meat species identifications studies in raw or cooked meat products.     

抗狂犬病马血清效价ELISA检测试剂的制备

目的制备检测抗狂犬病马血清效价的ELISA试剂。方法采用ELISA间接法。先用抗狂犬病病毒IgY包被酶标板,并确定其最适包被浓度;制备酶标二抗,并确定其最佳使用浓度。对试剂的灵敏度、特异性、精密性、稳定性及与小鼠中和试验结果的相关性进行考核。结果抗狂犬病病毒IgY和酶标二抗的最适浓度分别为10!g/ml和1∶1500,试剂灵敏度为0.072IU/ml,特异性良好,批间及试验间变异系数均小于11%,37℃放置3和5d检测样品结果与放置前差异无显著意义,与小鼠中和试验结果呈正相关。结论所制备的抗狂犬病马血清效价ELISA检测试剂盒,可用于抗狂犬病马血清效价的检测。     

PCR assay for the identification of animal species in cooked sausages

A species-specific PCR assay was developed for the detection of low levels of pork, horse and donkey meat in cooked sausages. Oligonucleotid primers were designed for amplification of species-specific mitochondrial DNA sequences of each species and detected the presence of 0.01 ng of template DNA in water. When applying the assay to DNA extracts from sausages samples that were prepared from binary meat mixtures, it was possible to detect each species when spiked in any other species at the 0.1% level. In conclusion, it can be suggested that this assay can be used to determine mislabelled and/or fraudulent species substitution in comminuted meat products.     

Cholesterol photosensitised oxidation of horse meat slices stored under different packaging films

The effect of the type of packaging film (transparent vs. light-protecting red film) was evaluated on the formation of cholesterol oxidation products (COPs) in refrigerated horse meat slices stored in retail conditions under light exposure for 8 h. In meat wrapped with a transparent film, COPs increased from 233 (control) to 317 μg/g of fat, whereas the red film delayed cholesterol oxidation and offered protection against COPs formation, since COPs decreased from 173 (control) to 139 μg/g of fat after 8 h of light exposure. In addition, light opened the epoxy ring and led to the formation of triol, which was actually absent at T_0. A proper packaging film may represent a useful strategy to retard oxidative degradation in a light-sensitive, high pigment- and fat-containing food, such as horse meat.     

Breed effect on carcass and meat quality of foals slaughtered at 24 months of age

In some areas, horsemeat may be considered as an alternative to beef. And recent studies have shown that it may be positive from a nutritional point of view. However, little research has been done on the effects that influence horse carcass traits and meat quality. Breed effect has been studied by comparing two Spanish local breeds (Burguete and Hispano-Bretón) reared following the same traditional production system (24 months old). Some differences between breeds were observed for carcass quality measurements and colour parameters. Proximate composition was generally not affected by breed. Burguete foals had lower SFA and MUFA and higher PUFA than Hispano-Bretón ones. PUFA/SFA ratio from both breeds was higher than 0.4 and CLA levels were similar to those found in ruminants.     

Stress-related hormones in horses before and after stunning by captive bolt gun

In this work the slaughter-linked plasma modifications of some stress-related hormones in horses subject to standardized butchering procedures were investigated in order to highlight the compromised animal welfare during pre-slaughter handling. During pre-slaughter, animals show strong hardship behavioural patterns, probably due to being under life-threatening conditions. Blood samples from 12 male horses, ageing from 3 to 5 years, were collected before slaughtering in lairage, and during exsanguination after stunning. Catecholamines, cortisol and beta-endorphin concentrations were assessed in plasma samples by EIA. Results show that plasma beta-endorphin concentration did not increase significantly after stunning, while cortisol (P < 0.05) and catecholamines (P < 0.001) increased significantly. The ratio between the plasma level of norepinephrine and epinephrine decreased significantly (P < 0.001) during the time considered for observation underlining a greater involvement of adrenal medulla in the stress response. Moreover these results suggest that, under stress, the release of beta-endorphin could be different from that of ACTH.