琼脂糖凝胶的合适浓度对于回收酶切后质粒载体的重要性

目的：探讨琼脂糖凝胶的不同浓度对回收不同大小的酶切后质粒载体纯度的影响。方法：将2种质粒载体酶切,并经不同浓度的琼脂糖凝胶电泳分析,通过比较酶切前和酶切后载体的相对位置,研究胶浓度对回收酶切后载体纯度的影响。结果：不同浓度的琼脂糖凝胶中,酶切前和酶切后载体的相对位置会发生变化,对能否成功回收到纯度高的酶切后DNA片段有重要影响;质粒大小不同,胶浓度的影响也不同。结论：合适的胶浓度对于回收酶切后质粒载体具有重要意义,应选择合适的胶浓度回收酶切后质粒载体。     

苦杏仁精油对粘虫的触杀活性研究

以粘虫4龄幼虫为对象,采用"点滴法"研究了山杏种仁两种苦杏仁精油(含HCN和去HCN)对粘虫的触杀活性及其生长发育的影响.结果显示,处理后48 h,5～100 μL/mL浓度处理的试虫死亡率均在51.67%以上,40和100 μL/mL浓度处理的粘虫死亡率分别达到了95%(含HCN)/98.33%(去HCN)和100%,48 h时含HCN与除去HCN两种苦杏仁精油对粘虫的触杀致死中浓分别为5.10和4.69 μL/mL;苦杏仁精油对粘虫的化蛹期以及羽化期提前1～3 d,并有一定数量的畸形蛹出现,部分试虫虽能正常化蛹并羽化,但其蛹以及成虫虫体均较对照小,且羽化后蛾体萎缩,活动力降低,因展翅困难而死.可见,两种苦杏仁精油对粘虫具有很强的触杀活性,且去HCN的苦杏仁精油对粘虫的活性高于含HCN的苦杏仁精油,其对粘虫生长发育抑制活性主要表现化蛹期以及羽化期提前,苦杏仁精油有望发展为植物性杀虫剂.     

柠条锦鸡儿籽油体外抗真菌作用及其机制研究(英文)

参照美国临床实验室标准化委员会(NCCLS)推荐的《产孢丝状真菌的液基稀释法抗真菌药物敏感性试验方案》(M38-A),测定超临界CO2萃取的柠条锦鸡儿籽油对3种(每种15株)临床常见的皮肤癣菌的最低抑菌浓度(MIC);高效液相色谱法研究柠条锦鸡儿籽油对真菌细胞膜麦角甾醇生物合成的影响以探讨其作用机制。结果表明柠条锦鸡儿籽油对犬小孢子菌、须癣毛癣菌、红色毛癣菌的MIC范围分别为64～512μg/mL、32～512μg/mL、64～1024μg/mL;高效液相色谱法检测显示,与其生长对照菌相比,籽油作用的皮肤癣菌细胞膜上麦角甾醇含量明显降低,且具有剂量依赖性。柠条锦鸡儿籽油主要是通过影响真菌细胞膜上麦角甾醇的合成而发挥抗真菌作用。     

两株海洋真菌的鉴定及其次级代谢产物抑制烟草花叶病毒及抗肿瘤活性

摘要：【目的】通过对2株活性海洋真菌发酵产物提取物抑制烟草花叶病毒和抗肿瘤活性进行研究,为进一步得到活性纯品化合物作为抗病毒及抗肿瘤的先导化合物奠定基础。【方法】菌株发酵产物的粗提物是通过甲醇浸取并在真空条件下蒸干得到的。粗提物中溶于水的部分为水溶性部分,不溶于水的部分为脂溶性部分。通过间接酶联免疫法检测样品抑制烟草花叶病毒的活性,通过四甲基偶氮唑盐微量酶反应比色法（MTT法）检测样品抗肿瘤活性,通过形态及ITS rDNA序列法进行菌株鉴定。【结果】两株海洋真菌抑制烟草花叶病毒活性和抗肿瘤的活性均较高。分子鉴定结果显示,两株真菌分别与Penicillium oxalicum 和 Neosartorya fischeri 的同源性极高。菌株0312F1发酵液的水溶性部分具有抗病毒及抗肿瘤活性,菌株1008F1发酵液的脂溶性部分具有抑制烟草花叶病毒活性,而水溶性部分具有抗肿瘤活性。【结论】菌株0312F1和菌株1008F1发酵液的提取物抑制烟草花叶病毒的活性部位不同,而抗肿瘤活性部位相同。菌株0312F1发酵液提取物的水溶性活性部位对肝癌细胞BEL-7404的抑制效果比对胃癌细胞SGC-7901的抑制效果明显,而菌株1008F1发酵液提取物的水溶性活性部位对胃癌细胞SGC-7901的抑制效果比对肝癌细胞BEL-7404的抑制效果明显。     

ROS-Ca is associated with mitochondria permeability transition pore involved in surfactin-induced MCF-7 cells apoptosis

The surfactin can inhibit proliferation and induce apoptosis in cancer cells. Moreover, surfactin can induce cell death in human breast cancer MCF-7 cells through mitochondrial pathway. However, the molecular mechanism involved in this pathway remains to be elucidated. Here, the reactive oxygen species (ROS) and Ca²⁺ on mitochondria permeability transition pore (MPTP) activity, and MCF-7 cell apoptosis which induced by surfactin were investigated. It is found that surfactin evoked mitochondrial ROS generation, and the surfactin-induced cell death was prevented by N-acetylcysteine (NAC, an inhibitor of ROS). An increasing cytoplasmic Ca²⁺ concentration was detected in surfactin-induced MCF-7 apoptosis, which was inhibited by 1,2-bis (2-aminophenoxy) ethane-N,N,N′,N′-tetraacetic acid (BAPTA-AM, a chelator of calcium). In addition, the relationship between ROS generation and the increase of cytoplasm Ca²⁺ was determined. The results showed that surfactin initially induced the ROS formation, leading to the MPTP opening accompanied with the collapse of mitochondrial membrane potential (ΔΨ_m). Then the cytoplasmic Ca²⁺ concentration increased in virtue of the changes of mitochondrial permeability, which was prevented by BAPTA-AM. Besides, cytochrome c (cyt c) was released from mitochondria to cytoplasm through the MPTP and activated caspase-9, eventually induced apoptosis. In summary, surfactin has notable anti-tumor effect on MCF-7 cells, however, there was no obvious cytotoxicity on normal cells.     

兔肝金属硫蛋白的单晶

哺乳动物金属硫蛋白是一类低分子量,富含半胱氨酸,能大量结合金属元素的蛋白质,其氨基酸组成特殊,无组氨酸和芳香族氨基酸,没有二硫键。氨基酸序列独特,具有两个金属－巯基簇结构域,具有金属－巯基结合所形成的四面体结构的特征吸收光谱［１］。生物意义涉及生物机体微量元素储存、运输和代谢,重金属解毒,拮抗电离辐射,清除自由基,以及机体生长、发育、生殖、衰老、肿瘤发生、免疫、应激反应等各个方面。其研究与开发利用涉及农业、医药、保健、生物工程、环境保护等各个领域［２］。全世界科学家对其进行了广泛而深入的研究,生…     

云南鹤庆盆地末次盛冰期的孢粉记录与古季风

通过研究相当于末次盛冰期鹤庆古湖泊沉积物4．6－9．0m段的孢粉记录,对该区末次盛冰期阶段的植被与古季风变迁模式进行了恢复。该区末次盛冰期冷湿的气候特点与同时东部干旱的草原植被、青藏、高原的荒漠植被和黄土高原区风尘堆积存在明显差异,而与滇池的气候记录有较好的一致性。冰期内部的气候波动与深海氧同位素记录有较好的可比性。冰期冷锋强度的增加,与北方冬季风的经常入侵和冰期青藏高原的冷源效应有关。     

Carbon concentration and oxygen availability affect lipid and carotenoid production by carob pulp syrup‐grown Rhodosporidium toruloides NCYC 921

The simultaneous effect of oxygen availability and carbon source concentration on yeast lipid and carotenoid production has never been studied before. In this work, a Doehlert distribution design was used to study the simultaneous effect of carbon concentration and oxygen availability on Rhodosporidium toruloides NCYC 921 carotenoid and lipid production. A cheap industrial byproduct was used as carbon source (carob pulp syrup). A total sugar concentration of 106.3 g/L and a medium volume of 0.120 L induced the highest total carotenoid and total fatty acid productivities (4.60 μg/Lh and 0.029 g/Lh, respectively). Flow cytometry was used to assess yeast stress response under different cultivation conditions. The highest proportion of cells with permeabilised membrane (>20%) was induced when the cultivations were carried out at the highest sugar concentration studied (130.0 g/L) or when the culture reached the minimum final medium pH (4.60). The results showed that the total sugar concentration had a positive influence on the yeast biomass and carotenoid content, while the oxygen availability had little influence on the biomass concentration, but had a slight positive influence on the carotenoid content. Regarding the fatty acids, the two factors had a negative impact on the synthesis of these compounds.     

不同光强下生长的几种亚热带森林树木的Rubisco羧化速率和碳酸酐酶的活性

9月和12月测定了生长于3种不同光强（100％、36％和16％的自然光）下生长的乔木荷树、黧蒴和灌木九节、罗伞盆栽幼苗叶片的Rubisco羧化速率（RCR）、碳酸酐酶（CA）活性和细胞间CO2浓度（Ci)。当生长光强降低时,4种供试植物的RCR和CA活性明显降低。9月时生长在16％自然光下荷树的RCR和CA比100％自然光者分别降低55％和50％,藜蒴则降低20％和35％,耐有的灌木树的降幅较小,仅为33％－38％（RCR）和22％－30％（CA）。12月的RCR和CA的水平较9月时低,翌年1月时自然林不同光强下生长的同类植物的RCA和CA随光强变化也有类似的趋势。RCR和CA活性呈正相关性,且两者与Ci呈弱负相关。推测高光强可能有利于激活Rubisco,促进CA内化的CO2→DlC（可溶性碳）→CO2活性和DlC的传输过程。     

Summer distribution of the purplegray sculpin <Emphasis Type="Italic">Gymnocanthus detrisus</Emphasis> (Cottidae) in Waters of Primorsky Krai,Sea of Japan

Results of trawl catches show that in the summer period, in the waters of Primorsky Krai, Russia, Sea of Japan, the purplegray sculpin Gymnocanthus detrisus occurs at depths of 20 to 411 m, preferring the range 80–250 m. The temperature of the species’ habitat varies from 0.8 to 8.6 ° C, and the optimal one is 1.2–2.2 °C. G. detrisus occurs at the preferred depths more frequently in the southern area—the Peter the Great Bay, which is more favorable for foraging; in the area of North Primorsky Krai it was found both at greater and lesser depths. The latter is probably determined by the more limited spreading of waters with unsuitable temperatures for the species there. The body size of the purplegray sculpin grows with depth. Juveniles avoid depths over 200 m, where inflow of low-temperature waters is recorded. G. detrisus, which inhabits waters of Primorsky Krai, is represented mainly by females; the proportion of males exceeds that of females only in the 21–27 cm size group. This may be related to the lower growth rate in males after maturation as compared to females.