Fusion pore dynamics and insulin granule exocytosis in the pancreatic islet     

Takahashi N  Kishimoto T  Nemoto T  Kadowaki T  Kasai H 《Science (New York, N.Y.)》2002,297(5585):1349-1352

Insulin secretion from intact mouse pancreatic islets was investigated with two-photon excitation imaging. Insulin granule exocytosis occurred mainly toward the interstitial space, away from blood vessels. The fusion pore was unusually stable with a lifetime of 1.8 seconds. Opening of the 1.4-nanometer-diameter pore was preceded by unrestricted lateral diffusion of lipids along the inner wall of the pore, supporting the idea that this structure is composed of membrane lipids. When the pore dilated to 12 nanometers, the granules rapidly flattened and discharged their contents. Thus, our methodology reveals fusion pore dynamics in intact tissues at nanometer resolution.  相似文献   

A genomic regulatory network for development     

Davidson EH  Rast JP  Oliveri P  Ransick A  Calestani C  Yuh CH  Minokawa T  Amore G  Hinman V  Arenas-Mena C  Otim O  Brown CT  Livi CB  Lee PY  Revilla R  Rust AG  Pan Zj  Schilstra MJ  Clarke PJ  Arnone MI  Rowen L  Cameron RA  McClay DR  Hood L  Bolouri H 《Science (New York, N.Y.)》2002,295(5560):1669-1678

Development of the body plan is controlled by large networks of regulatory genes. A gene regulatory network that controls the specification of endoderm and mesoderm in the sea urchin embryo is summarized here. The network was derived from large-scale perturbation analyses, in combination with computational methodologies, genomic data, cis-regulatory analysis, and molecular embryology. The network contains over 40 genes at present, and each node can be directly verified at the DNA sequence level by cis-regulatory analysis. Its architecture reveals specific and general aspects of development, such as how given cells generate their ordained fates in the embryo and why the process moves inexorably forward in developmental time.  相似文献   

Cloning and expression of the human interleukin-6 (BSF-2/IFN beta 2) receptor   总被引：82，自引：0，他引：82  

K Yamasaki  T Taga  Y Hirata  H Yawata  Y Kawanishi  B Seed  T Taniguchi  T Hirano  T Kishimoto 《Science (New York, N.Y.)》1988,241(4867):825-828

Interleukin-6 (IL-6/BSF-2/IFN beta 2) is a multifunctional cytokine that regulates the growth and differentiation of various tissues, and is known particularly for its role in the immune response and acute phase reactions. A complementary DNA encoding the human IL-6 receptor (IL-6-R) has now been isolated. The IL-6-R consists of 468 amino acids, including a signal peptide of approximately 19 amino acids and a domain of approximately 90 amino acids that is similar to a domain in the immunoglobulin (Ig) superfamily. The cytoplasmic domain of approximately 82 amino acids lacks a tyrosine/kinase domain, unlike other growth factor receptors.  相似文献   

Major ecological transitions in wild sunflowers facilitated by hybridization   总被引：2，自引：0，他引：2  

Rieseberg LH  Raymond O  Rosenthal DM  Lai Z  Livingstone K  Nakazato T  Durphy JL  Schwarzbach AE  Donovan LA  Lexer C 《Science (New York, N.Y.)》2003,301(5637):1211-1216

Hybridization is frequent in many organismal groups, but its role in adaptation is poorly understood. In sunflowers, species found in the most extreme habitats are ancient hybrids, and new gene combinations generated by hybridization are speculated to have contributed to ecological divergence. This possibility was tested through phenotypic and genomic comparisons of ancient and synthetic hybrids. Most trait differences in ancient hybrids could be recreated by complementary gene action in synthetic hybrids and were favored by selection. The same combinations of parental chromosomal segments required to generate extreme phenotypes in synthetic hybrids also occurred in ancient hybrids. Thus, hybridization facilitated ecological divergence in sunflowers.  相似文献   

Mating preference and the direction of evolution in Drosophila     

Watanabe TK  Kawanishi M 《Science (New York, N.Y.)》1979,205(4409):906-907

Differences in the degree of successful matings between pairs of reciprocal hybrid matings indicate the direction of evolution among related species of Drosophila. Females of a derived species do not mate with males of the ancestral species, whereas females of the ancestral species readily mate with males of the derived species.  相似文献   

Histopathological and immunohistochemical features of proliferative lesions in the pituitary pars distalis of rats     

Takuya Doi  Takeshi Kanno  Junko Sato 《Journal of toxicologic pathology》2021,34(1):1

Pituitary proliferative lesions derived from the endocrine cells of the pars distalis are frequently encountered and adenomas/carcinomas are a common cause of death in standard 2-year carcinogenicity studies using various rat strains, especially Sprague-Dawley. This report describes the immunohistochemical characteristics of pituitary tumors derived from the pars distalis in rats. Prolactin (PRL)-containing tumors are the most common, with PRL/growth hormone (GH) dual positive tumor masses (PRL/GH co-positive tumor masses) being more prevalent than only PRL-positive tumor masses (PRL single-positive tumor masses). GH-containing tumors are relatively numerous and many of these are also PRL/GH co-positive tumor masses. TSH-containing tumors are common in females. PRL-containing tumors have been shown to increase the incidence of hyperlactation in males and mammary adenomas/adenocarcinomas in females, suggesting that these masses are functional tumors.  相似文献   

Genetic diagnosis of Rehmannia species micropropagated by tip tissue culture and an F¹ hybrid by RAPD analysis     

M. Hatano    R. Nakai    F. Kawanishi  K. Kedo  Y. Shoyama 《Plant Breeding》1997,116(6):589-591

Shoot formation was induced from the tip tissue of Rehmannia glutinosa f. hueichingensis on hormone-free Murashige-Skoog medium within 4 weeks of culture. Shoots were propagated on Murashige-Skoog medium supplemented with l.0mg/l benzy0ladenine for 4 weeks. Propagated shoots rooted on the hormone-free Murashige-Skoog medium during 4 weeks of culture. Total DNA was extracted from the leaves of a F₁ hybrid and its parents. R. glulinosa f. huekliingensis and R. glutinosa var, purpurea. Analysis of random-amplified polymorphic DNA (RAPD) using 10 arbitrary oligonucleotide 10-mers. showed the genetic homogeneity ofthe above three species. The F₁ hybrid was genetically intermediate between both parental plants, compared with the genetic distance between the F₁ hybrid and individual parents. Furthermore, the comparison of the band patterns between the F₁ hybrid, obtained from the crossing clearly showed that parts of the bands of both parents. R. glutinosa f. hueichingensis and R. glutinosa var. purpurea, were introduced into the F₁ hybrid.  相似文献   

Threshold change in forest understory vegetation as a result of selective fuelwood extraction in Nairobi, Kenya     

Takuya Furukawa  Kazue Fujiwara 《Forest Ecology and Management》2011,262(6):962-969

We examined whether heavy fuelwood collection can cause threshold change in understory forest community and evaluated how selective wood extraction might lead to delayed forest recovery in an urban forest of Nairobi, Kenya. Piecewise regression which represents strongest support for threshold change provided the best fit for the relationships between understory floristic composition (i.e. DCA axis 1) and human disturbance gradients (i.e. canopy cover, and distance from the slum), where threshold changes were detected at c.a. 350 m from the slum and c.a. 30% canopy cover. Only one tree species significantly indicated communities beyond the threshold while an aggressive invasive alien plant (IAP) Lantana camara was strongly represented. Total species diversity along the two human disturbance gradients peaked before the threshold was reached, suggesting that decline in species diversity along the prevailing disturbance gradient might be able to forecast threshold change. Tree species richness in the understory rapidly declined as the threshold was surpassed while other growth forms (i.e. shrubs, herbs and climbers) were relatively unaffected. The effect of selective tree cutting was indirectly impacting the forest understory as species richness pattern of preferred and non-preferred species paralleled that of trees and shrubs, respectively. Thickets of L. camara can negatively affect indigenous flora and its establishment was favored under selective fuelwood extraction removing certain tree species while leaving the IAP untouched. Shading can readily eliminate the IAP, but weak tree regeneration beyond the threshold suggested forest recovery might be delayed for longer than expected because of the interaction between selective fuelwood use and the IAP.  相似文献   

First report of Helleborus net necrosis virus isolated from hellebores with black death syndrome in Japan     

Takuya Shiraishi  Hideo Hoshi  Koki Eimori  Takeshi Kawanishi  Ken Komatsu  Masayoshi Hashimoto  Kensaku Maejima  Yasuyuki Yamaji  Shigetou Namba 《Journal of General Plant Pathology》2011,77(4):269-272

Helleborus net necrosis virus (HeNNV) in hellebores (Helleborus spp.) has been detected for the first time in Japan. Infected plants had black streaks on fresh leaves and black spots on sepals, which resembled the symptoms of black death disease. The morphology of the virus particles isolated from infected plants was comparable to that of carlaviruses. RT-PCR analysis showed that the entire HeNNV genomic sequence isolated in Japan shared 99% identity with that of HeNNV previously reported in the United States.  相似文献   

Effect of simulated acid rain on the growth of soybean     

Yoshishisa Kohno  Takuya Kobayashi 《Water, air, and soil pollution》1989,43(1-2):11-19

Soybean seedlings (Glycine max) grown in a glasshouse were exposed to simulated acid rain using a solution of deionized water containing sulfate, nitrate and chloride in concentrations and proportions equivalent to those in ambient rain water. Plants were subjected to acid rain treatment twice a week during the growing season, for a 1 hr period at a rate of 5 mm hr^?1. When the acid rain was below pH 3.0, visible symptoms developed in the young trifoliate leaves. However, at a pH above 3.0 there was no evidence of visible leaf injury; also tissue dry weights and leaf areas were not affected even after 7 weeks of exposure. The number of root nodules in plants exposed to acid rain at pH 4.0 tended to be higher than those of control plants maintained at pH 5.6, but decreased subsequently with decreasing pH. Based on our results current ambient levels of rain acidity in Japan should not have an adverse impact on seedling growth in soybean.  相似文献