黑糯玉米黑色素的提取工艺的研究

用黑糯玉米浸提液的吸光度值代替其中的黑色素含量,通过单因素试验研究了提取条件对吸光度的影响,为确定合理的黑糯玉米黑色素提取工艺提供一定的参考。采用正交试验确定了提取的最佳工艺条件:以95%的乙醇为提取剂,提取时间为2h,提取pH为7,提取料液比为1:8、提取温度为75℃。     

哺乳动物毛色形成研究进展

毛色是一种可利用的遗传标记,在确定杂交组合和品种纯度以及评价产品质量等方面有一定的用途,哺乳动物毛色是由黑色素细胞产生的真黑素和棕黑素之间的转换而形成的,控制哺乳动物毛色色素的基因很多,目前对哺乳动物毛色色素遗传的研究主要集中于人、鼠和猪.文章主要对哺乳动物黑色素和毛色的形成及其几个重要的遗传基因进行综述.     

玉米大斑病菌黑色素缺失突变体的获得及其生物学特性

DHN黑色素是许多植物病原真菌的致病相关因子,为明确黑色素在玉米大斑病菌致病过程中的作用,采用三环唑和紫外线复合诱变的方法获得了黑色素缺失的6个突变菌株,对突变菌株的生长量、产孢量、HT-毒素活性、致病力进行测定。结果显示,突变菌株产毒能力变化不大,但生长量下降,产孢量和致病力显著下降或完全丧失,野生型菌株的产孢量和侵染频率分别是突变菌株的30～50倍和5倍。突变菌株与黑色素共培养后,菌株M01-23a和M01-23b恢复了致病力,但病斑面积和侵染频率较小。玉米大斑病菌黑色素与致病力具有一定的相关性。     

Fundus pigment distribution in rhesus monkeys

There is growing evidence for an interaction among fundus pigmentation, character, geography and the function and structure of the outer retina. We examined three inbred groups of rhesus macaques (132 eyes) including all ages. One was a smaller (18 eyes) group. Coat colors were variations of brown-tan however, the smaller group had lighter 'golden' coats and colors. Fundus images were classified for pigmentation and its geographic distribution. In golden-coated animals there was bias toward nasal fundus hypopigmentation with the optic disk as a watershed demarcation zone, which extended in the superior-inferior direction. Temporal fundus hypopigmentation did not occur in the absence of nasal hypopigmentation. More common, darker coated samples showed a characteristic diffuse fundus pigmentation. There was no evidence for albinism or large variations in macular pigmentation. Rhesus monkeys can exhibit geographically controlled genetic development of fundus pigmentation. Hypopigmentation provides for access to the choroidal infrastructure.     

Sensitivity Detection Technique and Resistance Risk Assessment of Magnaporthe grisea to Tricyclazole

In vitro detection method for the sensitivity of Magnaporthe grisea to tricyclazole was studied, and the potential resistance risk of blast disease to tricyclazole was assessed. Both EC5o of hyphal melanization (ECso-H) and minimum inhibitive concentration of melanization in appressorial (MIC-A) by inhibitor tricyclazole showed positive correlation to the EC5o of tricyclazole against blast disease tested in vivo, with relative co-efficiency (R2) of 0.8995 and 0.8244, respectively. However, stability and reproducibility of ECso-H were better than those of MIC-A, suggesting that it could be used to detect the sensitivity of M. grisea to tricyclazole in vitro. Tricyclazole sensitivity of the progenies derived from single spores of the most sensitive isolate DY2 and the least sensitive isolate GY6 detected in sensitivity monitoring in 2000 was not stable, with mean EC50 values of 4.4968μg/mL and 5.4010μg/mL, respectively, indicating that the difference in EC5o between DY2 and GY6 was not caused probably by resistance variation. EC5o of GY6 did not increase significantly when continuously selected for twenty generations under the selection pressure of tricyclazole in vivo. However, the sensitivity of DY2 was decreased by 10-fold after selected for twenty generations.The results suggested that tricyclazole was still low resistance risk for M. grisea in China.     

从鱿鱼墨中精制黑色素

介绍了以鱿鱼墨为原料从中提取，精制黑色素的工艺。具体路线为：原料鱿鱼墨经水洗，酸洗，浓酸水解去除绝大多数杂质后，添加二甲亚砜（DMSO）使黑色素完全溶解，然后，加入丙酮改变溶液极性，减小黑色素的溶解度，从而使黑色素再次析出，经三次重结晶，以达到精制目的。在此基础上，测定了鱿鱼墨黑色素的一些物理和化学性制，精制所得黑色素呈黑褐色，不溶于水及通常的有机溶剂，但可溶于碱，浓硫酸，二甲亚砜等，紫外－可见光谱和红外光谱初步表明鱿鱼墨黑色素是以吲哚结构为主体的异聚物。     

山杏种皮黑色素提取工艺研究

研究了提取溶剂及其浓度、提取温度和有无氮气保护及提取时间对山杏种皮黑色素提取效果的影响,并对提取的山杏种皮黑色素与人工合成的多巴黑色素的理化性质进行了比较。结果表明,该黑色素适宜于用0.5mol/L NaOH在60℃下提取2次,每次12 h,提取宜在氮气下进行,以防止黑色素的过度氧化。在该工艺条件下,经过酸水解和进一步有机溶剂洗涤及反复沉淀纯化以后,可从5 g山杏种皮中得到黑色素237 mg,得率为4.73%;山杏种皮黑色素中总多酚含量较高,约为262 mg/g。山杏种皮黑色素与合成多巴黑色素的理化性质非常相似,不溶于水和常见的有机溶剂,在1 mol/L KOH溶液中完全溶解,pH小于3时发生沉淀,可被KMnO4、K2Cr2O7、NaClO和H2O2氧化漂白,多酚定性反应呈阳性;在紫外-可见光区没有吸收峰,红外光谱中在3 400 cm-1附近和1 650~1 620cm-1各有一个强的吸收带。     

玉米弯孢叶斑病菌致病相关黑色素和毒素合成基因协同表达研究初探

玉米弯孢叶斑病菌(Cochliobolus lunatus)次生代谢产生的黑色素和毒素是重要的致病因子。为明确DHN黑色素合成基因Brn1与毒素合成相关基因Clt-1之间的表达关系,以弯孢菌产黑色素及产毒素缺陷突变株为材料,采用Semi-Quantitative RT-PCR分析发现Brn1和Clt-1在黑色素合成基因Brn1沉默突变株T5和产毒素缺陷型突变株T806中的表达均同步受到抑制,初步证明Brn1与Clt-1在弯孢菌中的表达调控存在一定的关联性。紫外-可见光谱分析表明,Clt-1基因敲除突变株△Clt-1和△Clt-2黑色素的吸光值大于T5,低于野生菌株CX-3,与发酵液颜色变化一致。红外光谱分析表明,CX-3、△Clt-1、△Clt-2和T5 4种菌株分泌的胞外黑色素之间有一定的差异。其中,T5在2854cm-1处几乎没有吸收峰,即缺失了C-H基团;在1745.01cm-1、1550.84cm-1、1379.68cm-1处都没有特征吸收峰,即没有C=C的伸缩振动峰。T5缺失了DOPA黑色素特性,说明Brn1基因可能与上述2个基团的合成存在某些联系。该研究对Brn1与Clt-1协同表达关系进行了初步探索,为在系统生物学水平上揭示玉米弯孢叶斑病菌致病机理奠定了基础。     

The effect of different carotenoid sources on skin coloration of cultured red porgy (Pagrus pagrus)

This study presents data on the effect of carotenoid sources on skin coloration of red porgy (Pagrus pagrus). Three experiments were conducted: in the first, fish were fed an astaxanthin (Naturose^®)‐supplemented diet, while the second fish received diets supplemented with β‐carotene (Rovimix β‐caroten^®) or lycopene (Lyc‐O‐Mato^®): Carotenoids were added to the level of 100 ppm in each diet, while a non‐carotenoid‐supplemented diet served as a control. In the third experiment, the effect of dietary protein/carbohydrate ratio on melanin content in the skin was investigated. For this experimentation, four diets were formulated to contain 50/23, 40/32, 30/48 and 20/59 protein/carbohydrate ratio. Naturose^® astaxanthin increased total carotenoid content in the dorsal skin area while β‐carotene and lycopene seem to have had no significant effect. Naturose^® was the only carotenoid source that had a significant effect on skin hue, promoting a reddish coloration to the dorsal skin area and a ventral hue similar to wild red porgy. No apparent effect of carotenoid source on skin melanin content was observed. In contrast, dietary protein/carbohydrate ratio affected melanin content in the skin. The fish fed the 50/23 diet showed significantly higher values. Farmed red porgy had eight times higher dorsal‐skin melanin content than wild ones.