菠菜捕光CP29复合物能量调节的结构研究

CP29是一种高等植物光合系统II中的次要捕光复合物,可为光合作用吸收和转移光能．并在光保护中发挥重要作用。我们得到了2．8埃解析度的菠菜CP29的晶体结构。每个CP29单体包括13个叶绿素和3个类胡萝卜素分子．     

生物物理所解析菠菜次要捕光复合物CP29三维晶体结构

中科院生物物理所常文瑞院士课题组通过研究,解析了高等植物光合膜蛋白——菠菜次要捕光复合物CP29的2．8A分辨率晶体结构CP29晶体结构。晶体结构显示,CP29脱辅基蛋白具有三段跨膜螺旋和两段位于类囊体腔侧的两亲性螺旋。每个单体结合有13个叶绿素（ChB分子及3个类胡萝卜素分子。根据晶体结构,CP29中完整精确的色素网络得以构建。     

香根草提取物对二化螟生长发育及体内保护酶活力的影响

将香根草地上部分不同极性溶剂(石油醚、乙酸乙酯、正丁醇和水)的提取物加入到人工饲料中喂食二化螟幼虫,进行了提取物对二化螟初孵幼虫的毒杀作用、三龄幼虫的生长发育抑制作用及其体内保护酶(POD,SOD和CAT)活性影响的测定分析。结果表明,不同溶剂的提取物(0.01 g/m L)对二化螟幼虫均有毒杀作用,其作用大小排序为石油醚乙酸乙酯正丁醇水,其中石油醚提取物处理3 d后二化螟初孵幼虫存活率为15.8%,5 d后存活率为0.8%。三龄幼虫取食添加了不同提取物(0.05 g/ml)的人工饲料7 d后,生长发育均得到明显抑制,以石油醚和乙酸乙酯提取物作用最强,生长发育抑制率分别达111.11%和109.50%;同时,三龄幼虫体内的SOD活力明显高于对照,CAT和POD活力明显低于对照,其中石油醚和乙酸乙酯提取物和对照差异均达显著水平。研究表明香根草中含对二化螟幼虫有毒杀和生长发育抑制作用的活性物质,以石油醚和乙酸乙酯提取物中最为丰富。香根草提取物扰乱了二化螟幼虫体内保护酶SOD、CAT和POD的动态平衡,使虫体内自由基的清除遇到障碍,从而对其产生毒害作用。     

环境激素壬基酚对家蚕生殖发育的影响

壬基酚(NP)是一种新确认的环境激素(EH)。为探讨EH对鳞翅目昆虫的性激素作用,用添加NP的人工饲料饲养家蚕,调查NP对生殖发育的影响。结果显示,刚孵化家蚕幼虫添毒72 h和120 h的LC50分别为1.1392、1.0695 mmol/kg。添毒NP1.000 mmol/kg以上浓度,家蚕在幼虫期死亡而不能完成世代。从生殖腺系数看,0.500 mmol/kg以下浓度的NP,对家蚕幼虫和蛹的睾丸生长无不良影响(P>0.05);大于0.250 mmol/kg的NP,能显著抑制雄蛾的睾丸生长(P<0.05);小于0.500 mmol/kg的NP,5龄幼虫和24 h龄蛹精细胞数量显著增加(P<0.05);高于0.125 mmol/kg的NP,168h龄蛹和24h龄蛾的精子数量显著少于对照(P<0.01)。高于0.125 mmol/kg的NP,5龄幼虫和蛹的卵细胞生长和发育被抑制(P<0.05),雌蛾造卵数和产出卵数减少(P<0.05),受精率降低(P<0.05)。NP通过抑制家蚕生殖腺的生长和生殖细胞的发育表现雌激素效应。     

DMSA对家蚕杀虫双中毒的解毒效果

本试验模拟生产上家蚕微量杀虫双中毒的情况，研究了家蚕添食不同剂量的ＤＭＳＡ对其微量中毒的解毒效果．试验表明，添食ＤＭＳＡ对缓解杀虫双中毒蚕的中毒程度、改善营茧状况、提高结茧率和饲育成绩，均有显著作用，且在本试验的范围内，５０００×的添食解毒区比１００００×的添食解毒区效果更佳     

藻类的一株奇芭——球石藻

藻类是营光合自养的低等植物群．目前已经定名的约5万种．其中约2／3为单细胞藻．藻类有非常丰富的生物多样性．是生物学基础理论研究的重要基地：藻类是重要的生态调节因子，在碳、氮、磷等元素的循环中起着重要的作用：藻类是丰富的宝库．将对人类的健康和生活做出重要的贡献。     

家蚕丝胶蛋白基因1(ser-1)启动子的克隆及其活性分析

家蚕ser-1基因是中部丝腺中特异表达组织特异性基因。为研究家蚕ser-1基因在时空上的调控机制,用PCR的方法克隆了家蚕ser-1基因启动子并进行序列分析,进一步构建了由ser-1基因启动子驱动报告基因DsRed的新型表达质粒pSK-ser-DsRed-PolyA,并通过蚕体和家蚕BmN细胞进行了瞬时表达。结果显示,家蚕ser-1基因启动子的TATA框的保守序列为TATAAAA,位于-24～-30处,CAAT框位于-112～-115处;ser-1基因启动子可以驱动红色荧光基因DsRed在家蚕幼虫的中部丝腺组织和培养的BmN细胞中瞬时表达。     

人工饲料pH值和缓冲性能对家蚕（Bombyx mori）生长发育的影响

由控制饲料的ｐＨ值和缓冲液浓度来确定饲料的缓冲力，并配制不同水平的人工饲料饲育家蚕，检测三者间对饲料质量影响的主次．结果表明：饲料的缓冲力、ｐＨ值以及缓冲液浓度对家蚕的生长发育有显著影响．饲料缓冲液浓度和缓冲力的增加，饲料ｐＨ值的降低，都会引起蚕体重增量、相对生长率和净生长效率的降低，龄期经过的延长、消化后用于能量代谢的食物量的增加．在检验的ｐＨ值范围内（４．０～５．５），饲料ｐＨ值对家蚕生长发育和适口性的影响要小于饲料缓冲力，而略大于缓冲液浓度．     

粘红酵母生产类胡萝卜素的发酵条件研究

本文研究了不同的碳源、氮源和生长因子(核黄素、玉米浆)对粘红酵母2.102的生物量以及发酵生产类胡萝卜素的影响。并用正交试验方法对碳源、氮源、pH值等培养条件进行了优化筛选。结果表明:30g/L麦芽糖,10g/L酵母膏分别作为碳源和氮源,pH值6.0,添加0.03‰的核黄素和0.6%的玉米浆为最佳的培养基组成。在上述条件下,28℃振荡培养72h,类胡萝卜素产量最高可以达到10.21mg/L。     

人工饲料pH值和缓冲性能对家蚕生长发育的影响

由控制饲料的ｐＨ值和缓冲液浓度来确定饲料的缓冲力，并配制不同水平的人工饲料饲育家蚕，检测三者间对饲料质量影响的主次。结果表明：饲料的缓冲力、ｐＨ值以及缓冲液度对家蚕的生长发育有显著影响，饲料缓冲液浓度和缓冲力的增加，饲料ｐＨ值的降低，都会引起蚕体重增量、相对生长率和净生长效率的降低，龄期经过的延长、消化后用于能量代谢的食物量的增加。在检验的ｐＨ值范围内（４．０￣５．５），饲料ｐＨ值对家蚕生长发育和     

Antioxidant vitamins and chemoprevention

Free radicals play an important role in human carcinogenesis and the mechanism of their counteraction by antioxidant vitamins has been reviewed. It seems more likely that these vitamins work in concert rather than acting singly. Currently available data are compatible with the notion that these vitamins act as chemopreventives against some important cancers, e.g. carotenoids for lung cancer, ascorbic acid for salivary gland cancer, tocopherols for head and neck cancers etc. Thus, a greater consumption of fruits and vegetables should be encouraged as they are the natural sources of these chemopreventive, antioxidants along with other protective factors packaged by nature. However, much work still remains to be done to establish the role of antioxidant vitamins in carcinogenesis.     

Production of carotenoid sarcinaxanthin by Kocuria palustris isolated from Northeastern Brazil Caatinga soil and their antioxidant and photoprotective activities

BackgroundThis study aimed to produce carotenoids of two bacterial strains obtained and isolated from Caatinga soil in Northeastern Brazil and to evaluate their antioxidant and photoprotective activities. The morphological identification of bacteria was performed by Gram staining and molecularly confirmed through the 16S rRNA gene. The production of carotenoids was performed on two 2³ factorial designs to analyze the influence of independent variables (temperature range, luminosity, agitation, spiral presence, and bacterial isolate type) for maximum carotenoid yield. The selected condition has been transferred to a bioreactor (10L). The identification of carotenoids was performed by liquid chromatography (HPLC) and mass spectrometry (LC-MS). Antioxidant activity was determined by inhibiting the β-carotene/linoleic acid system and the effectiveness as sunscreen was measured through its sun protection factor (SPF).ResultsThe results revealed that the isolates FT-7.22 and FT-5.12 were identified as Kocuria palustris; producers of a rare C50 carotenoid sarcinaxanthin. This is the first report on the production of carotenoids by this species from the Caatinga Domain. The pigment that was obtained from the Tryptic Soy Broth (TSB) medium in the best conditions of the factorial designs (increased agitation, aeration, and light exposure) exhibited a significant increase in the carotenoid production. The isolated FT-7.22 reached a higher sarcinaxanthin concentration (112,480 μg/L), and it exhibited promising antioxidant (76.53 ± 0.09%) and photoprotective activities (SPF = 9.36 ± 0.52).ConclusionsThis study demonstrated the ability of K. palustris to produce carotenoid sarcinaxanthin with antioxidant and photoprotective activities so that it can be applied in cosmetic formulations.How to cite: Mendes-Silva TCD, Vidal EE, de Souza RFR, et al. Production of carotenoid sarcinaxanthin by Kocuria palustris isolated from Northeastern Brazil Caatinga soil and their antioxidant and photoprotective activities. Electron J Biotechnol 2021;53. https://doi.org/10.1016/j.ejbt.2021.05.004