Toxicological evaluation of transgenic rice flour with an Escherichia coli phytase gene appA by sub‐chronic feeding study in Wistar rats

BACKGROUND: Phytase is increasingly used as an ingredient in swine and poultry feeds to improve the bioavailability of phytate‐bound phosphorus and reduce the supplement of elemental phosphorus in feeds. Recently, a transgenic rise (TGR) with phytase appA gene from E. coli has been developed in Taiwan. To assure the food safety of this TGR, we performed a sub‐chronic whole‐food feeding study with Wistar rats. RESULTS: Weaned feeding male and female rats were divided into TGR and non‐TGR (NTGR) groups (20 rats per group), and fed diets containing 76.8% rice flour of TGR and NTGR, respectively. After 93 days feeding, although some hematological findings and blood chemistry values differed significantly between the TGR and NTGR groups, all values were still within the normal range for rats of this age and sex. No adverse effects of TGR were observed in terms of animal behavior, weight gain, or feed utilization rate. Necropsy at the end of the experiment indicated that neither pathological lesions nor histopathological abnormalities were present in organs such as liver, kidney, intestines and testes of rats in TGR and NTGR groups. In addition, no significant differences (P > 0.05) were observed in relative organ weights, hemograms and blood indices of rats between the two groups. CONCLUSION: These results demonstrated that in a 93‐day feeding study with Wistar rats a diet containing 76.8% of TGR flour having a phytase activity of about 1500 U kg^?1 body weight per day has no adverse effects. Copyright © 2007 Society of Chemical Industry     

Assessment of compositional changes during ripening of transgenic papaya modified for protection against papaya ringspot virus

BACKGROUND: Papaya (Carica papaya L.) production is limited by over 20 viruses, the most damaging of which is papaya ringspot virus (PRSV). Owing to a lack of suitable PRSV‐resistant sources in Carica germplasm, transgenic resistance using the coat protein (cp) gene of a local PRSV strain is being developed to manage the disease in Jamaica. For assurance of food safety, the nutritional and antinutritional composition of transgenic papayas during ripening was compared with that of unmodified control samples. RESULTS: Mature unripe fruits of transgenic and non‐transgenic papayas were repeatedly harvested and stored at room temperature for 1 week periods, during which random samples were assessed. With the exception of one transgenic line, no significant differences (P > 0.05) were observed in selected nutrients and antinutrients between the control and test samples at three stages of maturity, although a few random variations were noted. CONCLUSION: Transformation with viral cp gene and two marker genes did not produce any major unintended alterations in either the nutritional or the antinutritional composition of transgenic papayas. These findings must be compared with other physicochemical and safety assessments to provide a scientific basis for concluding substantial equivalence with conventional papayas available on the market in Jamaica. Copyright © 2008 Society of Chemical Industry     

痕量及微量转基因大米成分半巢式PCR检测方法的建立

采用半巢式PCR技术建立了食品中痕量及微量转基因大米成分的检测方法。根据大米内源SPS基因以及转基因大米Bt63含有的外源Cry1A(b)/Cry1A(c)融合基因和Btc基因,分别设计了6对普通与半巢式PCR引物。扩增结果显示,针对理论DNA浓度的检测灵敏度,普通PCR扩增灵敏度为1ng/μl左右,半巢式PCR扩增灵敏度达到10-3～10-4ng/μl,半巢式PCR比普通PCR方法提高了103～104倍;在质量百分比的检测灵敏度方面,普通PCR方法扩增灵敏度在0.1%～1%之间,半巢式PCR方法的检测灵敏度能够达到0.001%～0.01%,半巢式PCR比普通PCR方法要提高10倍以上。在实际样品的检测中,速冻汤圆、婴儿米粉及芝士小圆饼等食品经普通PCR扩增,其内源SPS基因条带模糊或未扩增到,进一步采用半巢式PCR扩增后,能够得到清晰明亮的特异性条带。所有样品均未扩增到外源Cry1A(b)/Cry1A(c)和Btc基因。     

改良十六烷基三甲基溴化铵-磁珠核酸提取方法及在植物转基因检测中的应用

目的 建立一种快速、高效、便捷的植物基因组DNA提取方法并运用于植物转基因检测。方法 改良传统的十六烷基三甲基溴化铵(cetyltrimethylammonium ammonium bromide, CTAB)方法, 并结合磁珠吸附基因组DNA, 配合核酸自动提取系统提取水稻和加工米粉中的核酸, 荧光聚合酶链式反应(polymerase chain reaction, PCR)检测Bt63大米转基因成分, 并与另外4种提取方法的结果进行对比, 评价提取效果。结果 5种不同方法中CTAB-磁珠法提取的样品基因组DNA浓度和质量最佳, 荧光PCR检测低浓度Bt63转基因成分(0.01%)的Ct值最小, 检测结果最好。结论 该方法可高效快速地提取植物核酸, 在低含量的转基因成分检测中相比其他几种方法具有绝对优势。     

水稻密码子优化的cry2A^＊基因在大肠杆菌中的表达及其表达产物的纯化

通过PCR从克隆载体puC18-3Z/Cry2A*上扩增水稻偏爱型密码子优化的抗虫基因cry2A*,经限制性内切酶Nde I和BamH I双酶切定向插入到原核表达载体pET-28a( ),成功构建了在表达蛋白的N端只带有6个组氨酸标签的融合蛋白表达载体pET-28a( )/Cry2A*,并转入人肠杆菌BL21(DE3)中.通过对其表达条件进行优化,发现在IPTG浓度为0.05mmol/L、诱导时问为3h、诱导温度为20℃的表达条件下目的蛋白大部分以可溶形式进行表达.采用Ni-NTA亲和柱纯化得到高纯度目的蛋白,薄层扫描分析蛋白纯度达到95%.     

Comparison of the crystalline properties and structural changes of starches from high-amylose transgenic rice and its wild type during heating

A transgenic rice line (TRS) enriched amylose and resistant starch has been developed by antisense RNA inhibition of starch branching enzymes. In this study, gelatinisation and crystalline properties, swelling power, water solubility, morphological and structural changes of starches from TRS and its wild-type Teqing (TQ) were carefully investigated during heating. Compared to TQ, TRS starch showed higher gelatinisation temperatures, lower gelatinisation enthalpy and swelling power. Morphological and structural changes showed that TQ starch drastically swelled after 70 °C, then gradually disrupted with increasing heating temperature. The surrounding band of TRS starch restrained granule swelling, though the subgranules disrupted to form the cavity. The results of spectroscopic analyses indicated that A-type crystalline of TQ changed to amorphous starch after 75 °C, while C-type crystalline of TRS gradually changed to B-type crystalline after 75 °C, then became amorphous starch at 95 °C. These results add to our understanding of the effect of heating on the high-amylose rice starch.     

Advances in Transgenic Mouse Models to Study Infections by Human Pathogenic Viruses

Medical research is changing into direction of precision therapy, thus, sophisticated preclinical models are urgently needed. In human pathogenic virus research, the major technical hurdle is not only to translate discoveries from animals to treatments of humans, but also to overcome the problem of interspecies differences with regard to productive infections and comparable disease development. Transgenic mice provide a basis for research of disease pathogenesis after infection with human-specific viruses. Today, humanized mice can be found at the very heart of this forefront of medical research allowing for recapitulation of disease pathogenesis and drug mechanisms in humans. This review discusses progress in the development and use of transgenic mice for the study of virus-induced human diseases towards identification of new drug innovations to treat and control human pathogenic infectious diseases.     

棉花优质高产抗旱节水技术大田试验研究

按照生态农业工程理论和抗旱节水工程技术要求,对棉花转基因抗旱品种、不同密度、不同基肥N、P的施用量进行田间水分胁迫综合试验.经在关中灌区3年试验研究结果表明:密度以每公顷种植7.5万株比种植4.5、6万株分别增产671.854、83.30 kg,增产57.49%和41.36%.品种陕402(早熟)、陕576(中早熟)分别比中棉所41(中熟)增产16.62%和16.17%.施磷酸二铵比尿素增产,每公顷施1502、25 kg分别增产11.35%和10.53%.抗旱节水农业工程育种和农艺节水工程技术结合,不仅可降低生产成本44%~47%,还可提高产量和品质,增收1 050~5 000元/hm2,同时节约了水资源,保护了农业生态环境.     

EK100 and Antrodin C Improve Brain Amyloid Pathology in APP/PS1 Transgenic Mice by Promoting Microglial and Perivascular Clearance Pathways

Alzheimer’s disease (AD) is characterized by the deposition of β-amyloid peptide (Aβ). There are currently no drugs that can successfully treat this disease. This study first explored the anti-inflammatory activity of seven components isolated from Antrodia cinnamonmea in BV2 cells and selected EK100 and antrodin C for in vivo research. APPswe/PS1dE9 mice were treated with EK100 and antrodin C for one month to evaluate the effect of these reagents on AD-like pathology by nesting behavior, immunohistochemistry, and immunoblotting. Ergosterol and ibuprofen were used as control. EK100 and antrodin C improved the nesting behavior of mice, reduced the number and burden of amyloid plaques, reduced the activation of glial cells, and promoted the perivascular deposition of Aβ in the brain of mice. EK100 and antrodin C are significantly different in activating astrocytes, regulating microglia morphology, and promoting plaque-associated microglia to express oxidative enzymes. In contrast, the effects of ibuprofen and ergosterol are relatively small. In addition, EK100 significantly improved hippocampal neurogenesis in APPswe/PS1dE9 mice. Our data indicate that EK100 and antrodin C reduce the pathology of AD by reducing amyloid deposits and promoting nesting behavior in APPswe/PS1dE9 mice through microglia and perivascular clearance, indicating that EK100 and antrodin C have the potential to be used in AD treatment.     

Amyloid-β Processing in Aged S100B Transgenic Mice Is Sex Dependent

(1) Background: Calcium-binding protein S100B is involved in neuroregeneration but has also been associated with neurodegeneration. These contrasting effects may result from concentration or duration of exposure. We investigated the effect of long-term increased S100B levels on amyloid-β processing in one-year-old transgenic (tg) mice with 12 copies of the murine S100B gene with specific consideration of sex and specific brain regions. (2) Methods: S100B and amyloid-β 42 (Aβ42) were quantified in serum, cerebrospinal fluid (CSF), adipose tissue, and different brain regions by ELISA in wild-type (wt) and S100Btg mice (each n = 7 per group). Thioflavin T (ThT) and Aβ immunostaining were performed for visualization of Aβ deposition. (3) Results: S100B in serum, CSF, and brain was significantly increased in S100Btg mice of both sexes. Aβ42 was significantly increased in the hippocampus of male S100Btg mice (p = 0.0075), and the frontal cortex of female S100Btg mice (p = 0.0262). ThT and Aβ immunostaining demonstrated Aβ deposition in different brain regions in S100Btg mice of both sexes and female wt. (4) Conclusion: Our data validate this experimental model for studying the role of S100B in neurodegeneration and indicate that Aβ processing is sex-dependent and brain region-specific, which deserves further investigation of signaling pathways and behavioral responses.