NaCl胁迫对杂交狗牙根品种‘苏植2号’和‘Tifgreen’生长及Na＋和K＋积累的影响

对0（对照）和20g·L-1NaCl胁迫条件下杂交狗牙根（Cynodondactylon×C.transvaalensis）品种‘苏植2号’（‘SuzhiNo.2’）和‘Tifgreen’不同部位的生长状况以及Na＋和K＋积累的差异进行了研究,并分析了2个品种间Na＋、K＋转运调控机制的差异。结果显示：在NaCl胁迫条件下,2个品种的叶片相对枯黄率、地下茎和根系的相对干质量、叶片和根系的Na＋含量和Na＋/K＋比以及钠钾选择性转运系数增加;修剪茎叶及冠层和地上部的相对干质量、植株相对总干质量以及叶片和根系的K＋含量均降低,但茎叶含水量无显著变化。NaCl胁迫条件下,不同土层中2个品种的根系相对干质量均不同程度增加,且20-40和40-60cm土层中根系干质量的增幅大于0-20cm土层;在0-20cm土层中2个品种根系的分配比例均有所降低,而在20-40和40-60cm土层中则不同程度提高。与‘Tifgreen’相比,NaCl胁迫条件下‘苏植2号’叶片相对枯黄率、Na＋含量和Na＋/K＋比更低,修剪茎叶及冠层和地上部的相对干质量、植株相对总干质量、叶片K＋含量和钠钾选择性转运系数更高;在20-40和40-60cm土层中‘苏植2号’根系相对干质量显著高于‘Tifgreen’,根系分配比例总体也高于‘Tifgreen’。综合比较结果表明：‘苏植2号’的抗盐性强于‘Tifgreen’,可能与其深层根系分配量更高和钠钾选择性转运能力较强有关。     

BubR1 is modified by sumoylation during mitotic progression

BubR1 functions as a crucial component that monitors proper chromosome congression and mitotic timing during cell division. We investigated molecular regulation of BubR1 and found that BubR1 was modified by an unknown post-translation mechanism during the cell cycle, resulting in a significant mobility shift on denaturing gels. We termed it BubR1-M as the nature of modification was not characterized. Extended (>24 h) treatment of HeLa cells with a microtubule disrupting agent including nocodazole and taxol or release of mitotic shake-off cells into fresh medium induced BubR1-M. BubR1-M was derived from neither phosphorylation nor acetylation. Ectopic expression coupled with pulling down analyses showed that BubR1-M was derived from SUMO modification. Mutation analysis revealed that lysine 250 was a crucial site for sumoylation. Significantly, compared with the wild-type control, ectopic expression of a sumoylation-deficient mutant of BubR1 induced chromosomal missegregation and mitotic delay. Combined, our study identifies a new type of post-translational modification that is essential for BubR1 function during mitosis.     

Mechanically Asymmetrical Triboelectric Nanogenerator for Self‐Powered Monitoring of In Vivo Microscale Weak Movement

Although much effort has been put in the studies of weak in vivo microscale movements due to its importance, the real‐time, long‐time, and accurate monitoring is still a great challenge because of the complexity of the in vivo environment. Here, a new type of mechanically asymmetrical triboelectric nanogenerator with ultrashort working distance and high anti‐interference ability is developed to accurately and real‐timely monitor the microscopically weak movement of intestinal motility at low frequencies even around 0.3 Hz. The intestinal status after the glucose absorption, and physiological states in different times also have been monitored successfully in the complex in vivo environment with many kinds of interference and noises. This work gives a new self‐powered, long‐time and in vivo technical way for the real‐timely gastrointestinal motility monitoring, and contributes to the detection of every kind of gentle movements in various complex bio‐systems.     

红树植物桐花树叶片多酚提取物对酪氨酸酶活性抑制及抗自由基和抗菌活性分析

采用超声波辅助-乙酸乙酯提取方法获得桐花树〔Aegiceras corniculatum(Linn.)Blanco〕叶片多酚提取物,研究了该提取物对酪氨酸酶活性的抑制作用及其动力学特征,并分析了该提取物对DPPH·自由基的清除作用及其抗菌活性。结果显示:多酚提取物得率约为(122.0±31.4)mg·g-1,提取物中多酚含量约为(521.8±17.2)mg·g-1。该提取物对酪氨酸酶活性的抑制作用呈明显正相关的量效关系,IC50为0.650 g·L-1,与阳性对照槲皮素对酪氨酸酶活性的抑制能力相近;该提取物通过降低酶活性实现对酪氨酸酶活性的抑制,且该抑制作用具有可逆性;随提取物质量浓度的提高酶促反应Km值增大、vm值减小,其动力学特征符合混合Ⅰ型抑制类型;对游离酶的抑制常数Ki为0.833 g·L-1,对酶-底物络合物的抑制常数Kis为1.823 g·L-1,表明该提取物与游离酶的亲和力大于其与酶-底物络合物的亲和力。随质量浓度提高,该提取物对DPPH·自由基的清除率逐渐增大并在0.000~0.600 g·L-1范围内呈明显量效关系,且IC50为0.304 g·L-1,与0.036 g·L-1槲皮素等效,显示该多酚提取物对自由基的清除能力较强。随质量浓度提高,该提取物对大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)和枯草芽孢杆菌(Bacillus subtilis)的抑菌圈直径均逐渐增大,显示该提取物对3种供试菌均有抑菌作用,最小抑菌浓度均为25 g·L-1。结果表明:通过深入的开发研究,桐花树叶片多酚提取物可作为兼具辅助防腐抑菌功能的新型酪氨酸酶抑制剂。     

A NEW SPECIES OF THE GENUS TOMOCERUS (S. S.) (COLLEMBOLA:TOMOCERIDAE) FROM CHINA

本文记述了鳞属华东地区１新种——近似鳞Ｔｏｍｏｃｅｒｕｓ（ｓ．ｓ．）ｓｉｍｉｌｉｓ,ｓｐ．ｎｏｖ．。本新种和克洛鳞Ｔ．（ｓ．ｓ．）ｋｉｎｏｓｈｉｔａｉＹｏｓｉ,１９５４非常相似,但可从小爪内齿、头部毛序及弹器齿节上棘状刚毛等特征相区别。正模♀,江苏滁县琅琊山,１９９０－ＩＶ－８,８０４０;副模：１♀,同正模;安徽黄山：１♂,２♀♀,１９９０－ＶＩ－３,８１６４、８１６９和８１７２;２♀♀,１９９０－ＶＩ－１６,８２２２;１♀,１９９３－ＩＸ－１２,８３４４;江苏：１♂,句容县宝华山,１９９０－Ｖ－２８,８１２５;１♀,南京紫金山,１９９４－ＩＶ－９,８３５５;１♀,灌云县,１９９５－Ｉ,８４３７。模式标本保存于南京大学生物系。     

Expression of Bacillus thuringiensis full-length and N-terminally truncated vip184 gene in an acrystalliferous strain of subspecies kurstaki

Vip3A is an 89-kDa protein secreted by Bacillus thuringiensis during vegetative growth. The 3.5 kb full-length vip184 gene was cloned from a wild-type isolate of B. thuringiensis, and the vip184S gene was constructed by deletion of the putative signal peptide encoding sequence. Both genes were expressed in the acrystalliferous strain Cry^–B of B. thuringiensis. Vip184 protein was observed mainly in the centrifuged pellets of B. thuringiensis Cry^–B(pHPT3), which contains the vip184 gene, and was less abundant in the concentrated supernatant. However, Vip184S proteins were not detected in the concentrated supernatant, but only in the pellets of Cry^–B(pHPT3S), which contains vip184S gene. This indicated that Vip184S proteins were not secreted into the culture medium and that the putative signal peptides were essential for the secretion of Vip184. The toxicity of Cry^–B(pHPT3) and Cry^–B(pHPT3S) were demonstrated against the neonate larvae of Spodoptera exigua and S. litura. Pellets and concentrated supernatant of Cry^–B(pHPT3) showed high activity against S. exigua and S. litura, but the Cry^–B(pHPT3S) strain was not toxic to either because of the deletion of N-terminal putative signal peptides. Therefore, this may suggest that the putative signal peptides are required for lethality.     

Cloning and Expression of <Emphasis Type="Italic">cyt</Emphasis>2Ba7 Gene from a Soil-Isolated <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis>

Bacillus thuringiensis (Bt) cyt genes coding hemolytic and cytolytic toxins constitute a gene family, which are divided into two groups: cyt1 and cyt2. A novel cyt2 gene was detected from a soil-isolated Bt strain T301, which was highly homologous to cyt2Ba1 and finally designated cyt2Ba7. Until now, Cyt2Ba has not been expressed alone in Bt or other hosts. In this study, the cyt2Ba7 gene was cloned into the vector pQE30 and expressed as a fusion protein with 6×Histidine residues in Escherichia coli. Unlike cyt1A, cyt2Ba7 was freely expressed and formed cytoplasmic inclusions without the need for a “helper” protein. The 6×His-tagged Cyt2Ba7 was purified in one step by Ni-NTA affinity chromatography, examined cytolytic activity on Sf9 cells, and developed as an antigen to obtain the antiserum against Cyt2Ba by subcutaneous injection into rabbits. This gene was also cloned into the Bt–E. coli shuttle vector pHT3101 and expressed in Bt strain 4Q7. Immunoblotting analysis revealed that the antiserum was remarkably selective and specific to Cyt2Ba. Received: 21 December 2001 / Accepted: 28 January 2002     

Cloning and Expression of the Binary Toxin Gene from Bacillus sphaericus IAB872 in a Crystal-Minus Bacillus thuringiensis subsp. israelensis

Acidity is an important environmental condition encountered by lactobacilli during food fermentation. In this report we show that triggering the stationary-phase acid tolerance response (ATR) in L. acidophilus CRL 639 depends on the final growth pH. In free-pH fermentation runs (final pH = 4.5), the cells were completely resistant to acid stress, whereas cells from cultures under controlled pH (pH = 6.0) were very sensitive. The relationship between the final pH and the development of cross-resistance to different kinds of environmental stress was also evaluated. The study of protein profiles showed the overexpression of 16 proteins from 6.5 to 70.9 kDa in stationary phase cells. Seven of these proteins (26.3, 41.4, 48.7, 49.3, 54.5, 56.1, and 70.9 kDa) were expressed as result of the stationary phase itself, while nine proteins (14.1, 18.6, 21.5, 26.9, 29.3, 41.9, 42.6, 49.6, and 56.2 kDa) were exclusively induced as a result of the drop in culture pH during free fermentation runs. These results strongly suggest the involvement of these proteins in cell adaptation to environmental changes. Received: 5 June 2000 / Accepted: 5 July 2000     

rps4作为苔藓植物候选条形码的可行性:基于GenBank数据的分析

对于苔藓植物DNA条形码研究来说,目前已提议的可用片段只有rbcL和trnH-psbA,并且均具有一定局限性.本文基于GenBank中3,365条rps4序列,利用遗传距离法和分子系统学方法评价它作为苔藓植物候选条形码的可行性.结果显示:(1)rps4序列覆盖了藓纲96%的科和苔纲88%的科,具有通用性;(2)rps4物种分辨能力为73.0%,并且它在6个序列最丰富的苔藓植物属(Plagiochila,Tortula,Plagiomnium,Pyrrhobryum,Pogonatum,Grimmia)内的物种识别能力均高于rbcL-a在同属中的分辨能力;(3)GenBank中已经积累了大量已知物种米源的rps4序列,可为DNA条形码物种鉴定提供一个参考数据库.因此,本文建议将rps4作为苔藓植物候选DNA条形码.尤其是当rbcL和trnH-psbA在某个具体类群中无法取得理想的物种识别效果时,rps4可作为补充.     

Validation of a cotton-specific gene, Sad1, used as an endogenous reference gene in qualitative and real-time quantitative PCR detection of transgenic cottons

Genetically modified (GM) cotton lines have been approved for commercialization and widely cultivated in many countries, especially in China. As a step towards the development of reliable qualitative and quantitative PCR methods for detecting GM cottons, we report here the validation of the cotton (Gossypium hirsutum) endogenous reference control gene, Sad1, using conventional and real-time (RT)-PCR methods. Both methods were tested on 15 different G. hirsutum cultivars, and identical amplicons were obtained with all of them. No amplicons were observed when DNA samples from three species of genus Gossypium, Arabidopsis thaliana, maize, and soybean and others were used as amplified templates, demonstrating that these two systems are specific for the identification and quantification of G. hirsutum. The results of Southern blot analysis also showed that the Sad1 gene was two copies in these 15 different G. hirsutum cultivars. Furthermore, one multiplex RT-quantitative PCR employing this gene as an endogenous reference gene was designed to quantify the Cry1A(c) gene modified from Bacillus thuringiensis (Bt) in the insect-resistant cottons, such as Mon531 and GK19. The quantification detection limit of the Cry1A(c) and Sad1 genes was as low as 10 pg of genomic DNA. These results indicat that the Sad1 gene can be used as an endogenous reference gene for both qualitative and quantitative PCR detection of GM cottons.