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排序方式: 共有100条查询结果,搜索用时 0 毫秒
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Shirley Yee Birt Stevens Shirlyn Coleman Jane E. A. Seabrook Xiu-Qing Li 《American Journal of Potato Research》2001,78(2):151-157
The shoot/plantlet regenerationin vitro of seven potato (Solanum tuberosum L.) cultivars from petioles with intact leaflets was assessed using six treatment combinations-a basal medium with or without silver thiosul-phate (STS) or thidiazuron (TDZ) at two concentrations (2 or 0.5 mg/l) of the indoleacetic acid (IAA). The basal medium consisted of Murashige and Skoog (MS) salts and vitamins supplemented with 3 mg/1 6-benzylaminopurine, and 1 mg/1 gibberellic acid, 30 g/l sucrose, and 7.0 g/l PHYTOAGAR. Two full sets repeats and one partial set repeat of independent experiments were conducted and all produced similar results. Silver thiosulphate decreased the regeneration frequency and number of shoots per callus. No significant changes were observed with thidiazuron. Regeneration rates of (100% ) with up to 20 shoots/plantlets per callus were achieved at 2 mg/1 IAA with cultivars Désirée, Kennebec, Niska, and Lenape. These cultivars still showed high regeneration rates (87%–98% ) on media with 0.5 mg/1 IAA, and good regeneration rates were also achieved by the other three cultivars (48%, 94%, and 50% for Chieftain, Russet Burbank, and Shepody, respectively). Even with the single medium protocol (0.5% IAA without thiosulphate or thidiazuron), Désirée, Lenape, and Niska exhibited a regeneration rate of 98%. The use of petiole-with-leaflet explants could be ideal for the regeneration step of potato genetic transformation protocol because of their high regeneration efficiency and their small cut surface area forAgrobacterium elimination after co-incubation. 相似文献
3.
Crystal structure of defensin HNP-3, an amphiphilic dimer: mechanisms of membrane permeabilization 总被引:34,自引:0,他引:34
Defensins (molecular weight 3500 to 4000) act in the mammalian immune response by permeabilizing the plasma membranes of a broad spectrum of target organisms, including bacteria, fungi, and enveloped viruses. The high-resolution crystal structure of defensin HNP-3 (1.9 angstrom resolution, R factor 0.19) reveals a dimeric beta sheet that has an architecture very different from other lytic peptides. The dimeric assembly suggests mechanisms by which defensins might bind to and permeabilize the lipid bilayer. 相似文献
4.
Suppression of the neoplastic phenotype by replacement of the RB gene in human cancer cells 总被引:80,自引:0,他引:80
H J Huang J K Yee J Y Shew P L Chen R Bookstein T Friedmann E Y Lee W H Lee 《Science (New York, N.Y.)》1988,242(4885):1563-1566
Mutational inactivation of the retinoblastoma susceptibility (RB) gene has been proposed as a crucial step in the formation of retinoblastoma and other types of human cancer. This hypothesis was tested by introducing, via retroviral-mediated gene transfer, a cloned RB gene into retinoblastoma or osteosarcoma cells that had inactivated endogenous RB genes. Expression of the exogenous RB gene affected cell morphology, growth rate, soft agar colony formation, and tumorigenicity in nude mice. This demonstration of suppression of the neoplastic phenotype by a single gene provides direct evidence for an essential role of the RB gene in tumorigenesis. 相似文献
5.
Hiroshi Ohta Kanae Takada Shidow Torisu Masashi Yuki Yu Tamura Nozomu Yokoyama Tatsuyuki Osuga Sue Yee Lim Masahiro Murakami Noboru Sasaki Kensuke Nakamura Masahiro Yamasaki Mitsuyoshi Takiguchi 《Veterinary immunology and immunopathology》2013
Inflammatory colorectal polyps (ICRPs) in miniature dachshunds are recently recognized as a major cause of large bowel diarrhea in this dog breed in Japan. ICRPs are characterized by the formation of multiple small polyps and a space-occupying large polyp in the colorectal area, and are thought to be a novel form of inflammatory bowel disease (IBD). In humans, specific cytokine patterns attributed to T helper (Th)1, Th17 and regulatory T cells have important roles in the pathogenesis of IBD. Thus, the aim of the present study was to assess the gene expression of cytokines of T cell subsets in the colorectal mucosa from dogs with ICRPs. Colorectal mucosal specimens from 10 dogs with ICRPs and 14 control dogs were used in this study. Interferon (IFN)-γ, interleukin (IL)-4, IL-17A and IL-10 mRNA expression was assessed using quantitative real-time PCR. IL-17A mRNA expression was significantly increased in large polyps compared to small polyps and controls. IFN-γ and IL-10 mRNA expression in large polyps were significantly higher than in controls. There was no significant difference in IL-4 mRNA expression among the three groups. IL-17A is thought to play important roles in the pathogenesis of ICRPs. IL-10 up-regulation could oppose the proinflammatory function of IL-17A. 相似文献
6.
Wei Yee Chan Elizabeth E. Hickey Stephen W. Page Darren J. Trott Peter B. Hill 《Journal of veterinary pharmacology and therapeutics》2019,42(6):682-692
Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N‐acetylcysteine (NAC), Tris‐EDTA and disodium EDTA) were investigated spectrophotometrically (OD570nm) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000–10,000 µg/ml and from 20,000–80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris‐EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16‐fold and eightfold higher than the MIC/MBC of NAC and Tris‐EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris‐EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm‐associated OE in dogs. 相似文献
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Epidemiology of H5N1 avian influenza 总被引:1,自引:0,他引:1
Yee KS Carpenter TE Cardona CJ 《Comparative immunology, microbiology and infectious diseases》2009,32(4):325-340
High pathogenic (HP) H5N1 avian influenza (AI) infection has been reported in domestic poultry, wildlife, and human populations since 1996. Risk of infection is associated with direct contact with infected birds. The mode of H5N1 spread from Asia to Europe, Africa and the Far East is unclear; risk factors such as legal and illegal domestic poultry and exotic bird trade, and migratory bird movements have been documented. Measures used to control disease such as culling, stamping out, cleaning and disinfection, and vaccination have not been successful in eradicating H5N1 in Asia, but have been effective in Europe. 相似文献
10.
Wang Z Carter JA Lagutchev A Koh YK Seong NH Cahill DG Dlott DD 《Science (New York, N.Y.)》2007,317(5839):787-790
At the level of individual molecules, familiar concepts of heat transport no longer apply. When large amounts of heat are transported through a molecule, a crucial process in molecular electronic devices, energy is carried by discrete molecular vibrational excitations. We studied heat transport through self-assembled monolayers of long-chain hydrocarbon molecules anchored to a gold substrate by ultrafast heating of the gold with a femtosecond laser pulse. When the heat reached the methyl groups at the chain ends, a nonlinear coherent vibrational spectroscopy technique detected the resulting thermally induced disorder. The flow of heat into the chains was limited by the interface conductance. The leading edge of the heat burst traveled ballistically along the chains at a velocity of 1 kilometer per second. The molecular conductance per chain was 50 picowatts per kelvin. 相似文献