Pollen Fertility Restoration by Nuclear Gene Fr in Cms Bean: Nuclear-Directed Alteration of a Mitochondrial Population

Two nuclear genes, Fr and Fr2, have been identified that restore pollen fertility to cytoplasmic male sterile (CMS) common bean (Phaseolus vulgaris L.) by apparently distinct mechanisms. Whereas Fr2 appears to suppress the expression of a male sterility associated mitochondrial sequence (designated pvs), Fr restores pollen fertility by causing the elimination of this unusual mitochondrial DNA segment. To further investigate the mechanism of Fr action, Fr and Fr2 were cointroduced into the nucleus of a bean line containing the sterility inducing cytoplasm. When the effect of pvs was suppressed by Fr2, the presence of Fr no longer directed the elimination of the mitochondrial pvs sequence. This result suggests that the Fr function is dependent on proper expression of the pvs sequence. To evaluate the temporal and spatial patterns of Fr action, we undertook a polymerase chain reaction-based approach to trace the fate of the pvs sequence in different tissues of F(2) and F(3) fertile-restored plants derived from a genetic cross between a cytoplasmic male sterile line of common bean, CMS-Sprite (frfr), and fertility restorer line R351 (FrFr). We demonstrate that the Fr-directed disappearance of pvs sequence occurs during flower development. Elimination of the pvs sequence from developing megaspores results in permanent fertility restoration in the following generations. Genetic analysis demonstrated that permanent fertility restoration, that is, the complete elimination of pvs from reproductive tissues requires two doses of the Fr allele or the absence of fr in F(2) individuals. The effect of Fr was reversible until full fertility was achieved. On the basis of these results, we propose a model for the mechanism of pvs elimination by the Fr gene and discuss the dynamics of pvs-containing mitochondrial transmission in the presence of the Fr gene.     

聚乙二醇定点修饰集成干扰素突变体Ⅱ

目的：用聚乙二醇（PEG）修饰集成干扰素突变体Ⅱ（IFN-Con-m2,IIFNm2）,通过纯化获得新型修饰分子并对该分子进行抗胰蛋白酶水解稳定性及初步药代动力学研究。 方法：将mPEG20000定点偶联到IIFNm2的第86位Cys残基上,修饰后的产物经CM层析后,以SDS-PAGE考察其纯度,用WISH-VSV系统进行生物活性测定;在0.1%胰蛋白酶条件下考察体外抗酶解稳定性;并以SD大鼠进行初步药代动力学研究,绘制血药浓度-时间曲线。采用3P87软件进行数据拟合,分析药物动力学参数。 结果：干扰素修饰率约为50%,且绝大多数以单修饰体（mono-PEG- IIFNm2）形式存在;提纯后mono-PEG-IIFNm2 的纯度大于98%,比活性约为修饰前IIFNm2的1%。抗胰蛋白酶水解试验表明：30min后,IIFNm2抗病毒活性残留为8%,mono-PEG-IIFNm2为41%。初步药代动力学研究显示：IIFNm的消除半衰期为(1.57±0.34)h,mono-PEG-IIFNm2为(18.0±4.0)h。 结论：成功地偶联了PEG和IIFNm2,建立了mono-PEG-IIFNm2的纯化工艺,PEG修饰能增加IIFNm2的体外抗胰蛋白酶水解稳定性,并显著延长体内半衰期。     

Analysis of nutrient components of food for Asian elephants in the wild and in captivity

Thirty-seven wild plants as food for Asian elephants in the field in Simao,Yunnan province,China and five cultivated plants as food for captive elephants in the Beijing Zoo were collected and analyzed for their main nutrient components.Protein,fat,fiber,dry material,ash as well as major microelements:calcium,kalium,zincum,sodium in the food were analyzed by standard methodology.No significant differences were found between the wild plants taken in the field and forage provided in captivity.However,the calcium content in the forage is significantly less than the average of those in the wild plants.It is suggested that the increase in calcium intake may contribute to the relief of low plasma calcium diseases of elephants in captivity.     

Evaluation of antimicrobial activity of certain Chinese plants used in folkloric medicine

Six selected plants, belonging to 3 families from Nanjing of China, were extracted with the solvent 95% (v/v) ethanol to yield 11 extracts. The extracts were evaluated for their effects on the growth of eight clinical bacteria, two fungi and one yeast using a modified agar diffusion method. The results showed that the majority of the extracts investigated showed greater activities against the Gram-positive bacteria than against the Gram-negative bacteria, the fungi and the yeast. The strongest antimicrobial activity was exhibited by the stem extracts of Mahonia fortunei against multiresistant Staphylococcus aureus strains, followed by the stem extracts of Mahonia bealei, while Bacillus thuringiensis was the most sensitive to all extracts.     

Rad9 plays an important role in DNA mismatch repair through physical interaction with MLH1

Rad9 is conserved from yeast to humans and plays roles in DNA repair (homologous recombination repair, and base-pair excision repair) and cell cycle checkpoint controls. It has not previously been reported whether Rad9 is involved in DNA mismatch repair (MMR). In this study, we have demonstrated that both human and mouse Rad9 interacts physically with the MMR protein MLH1. Disruption of the interaction by a single-point mutation in Rad9 leads to significantly reduced MMR activity. This disruption does not affect S/M checkpoint control and the first round of G₂/M checkpoint control, nor does it alter cell sensitivity to UV light, gamma rays or hydroxyurea. Our data indicate that Rad9 is an important factor in MMR and carries out its MMR function specifically through interaction with MLH1.     

Oxytocin is expressed by both intrinsic sensory and secretomotor neurons in the enteric nervous system of guinea pig

Single- and double-immunostaining techniques were used systematically to study the distribution pattern and neurochemical density of oxytocin-immunoreactive (-ir) neurons in the digestive tract of the guinea pig. Oxytocin immunoreactivity was distributed widely in the guinea pig gastrointestinal tract; 3%, 13%, 17%, 15%, and 10% of ganglion neurons were immunoreactive for oxytocin in the myenteric plexuses of the gastric corpus, jejunum, ileum, proximal colon, and distal colon, respectively, and 36%, 40%, 52%, and 56% of ganglion neurons were immunoreactive for oxytocin in the submucosal plexuses of the jejunum, ileum, proximal colon, and distal colon, respectively. In the myenteric plexus, oxytocin was expressed exclusively in the intrinsic enteric afferent neurons, as identified by calbindin 28 K. In the submucosal plexuses, oxytocin was expressed in non-cholinergic secretomotor neurons, as identified by vasoactive intestinal polypeptide. Oxytocin-ir nerve fibers in the inner circular muscle layer possibly arose from the myenteric oxytocin-ir neurons, and oxytocin-ir nerve fibers in the mucosa possibly arose from both the myenteric and submucosal oxytocin-ir neurons. Thus, oxytocin in the digestive tract might be involved in gastrointestinal tract motility mainly via the regulation of the inner circular muscle and the balance of the absorption and secretion of water and electrolytes.     

电刺激大鼠尾核头部镇痛的中枢效应—[^3H]—2脱氧...

Sokoloff's 2-deoxyglucose (2-DG) autoradiographic technique was used to identify changes of glucose metabolic rate in the rat brain following unilateral stimulation of the head of the caudate nucleus. The results were as follows. The local glucose metabolic rate after noxious stimulation was increased in the somatosensory cortex, cingulate cortex, ventroposterior and parafascicular nucleus of the thalamus, septal area, habenular nucleus, head of caudate nucleus, periaqueductal gray (PAG) and dorsal raphe nucleus (P < 0.05). After stimulating the head of the caudate nucleus, the local glucose metabolic rate of nucleus raphe magnus (rm) and nucleus paragigantocellularis (pgcl) was increased significantly and that of the PAG and dorsal raphe nucleus had a tendency to increase, while stimulation of the head of caudate nucleus could partially abolish the increased glucose metabolic rate in the somatosensory cortex, cingulate cortex, ventroposterior and parafascicular nucleus of the thalamus, septal area and habenular nucleus as induced by noxious stimulation. These results suggest that caudate stimulation is able to depress the activation of some brain structures related to nociception and to activate those related to antinociception. The pgcl, rm, PAG and dorsal raphe nucleus might be the key structures participating in the caudate stimulation produced analgesia.     

表油菜素内酯对月季切花保鲜作用的研究

本文初步探讨了表油菜素内酯（epiBR）对瓶插月季切花的保鲜作用。与对照（蒸馏水）和基本液（2％蔗糖＋500mgL-1柠檬酸＋250mgL-8-羟基喹啉＋25mgAgNO3）相比,经epiBR处理（基本液＋0．1mgL-1epiBR）的月季切花花枝坚挺,蓝变延迟,瓶插寿命延长1-1.5倍。测定有关生理指标表明,epiBR处理对月季切花瓶插花枝前期鲜重的增加及后期的保持有明显作用。并显著延缓花瓣和叶片质膜相对透性的增加,还能使瓶插前期花瓣还原糖含量增加。epiBR处理对花瓣蛋白质和叶片叶绿素含量变化无明显影响,而对花瓣花青素水平下降有轻微的促进作用。