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51.
Nuclear ETS and ITS, as well as plastid rpl16 and trnL-F DNA sequences were used to determine relationships among species of Graptopetalum (Crassulaceae) and closely related genera. Graptopetalum is member of a group of taxa restricted to North America, one of the centers of diversity of Crassulaceae; however, their phylogenetic relationships are not yet understood. Nineteen species of Graptopetalum and 24 species from nine other genera of Crassulaceae were sampled for use in three separate parsimony analyses: ITS alone, ETS alone, and a combined nuclear + plastid DNA analysis using all four gene regions. The ETS data set had the highest number of parsimony-informative sites, about 30% more than in ITS, but the most fully resolved tree resulted when the four DNA regions were combined. Only four subclades of the tree received moderate to strong bootstrap support, one of which includes all species of Graptopetalum having a single whorl of stamens. However, Graptopetalum is not monophyletic. Instead, Tacitus bellus and select species of Cremnophila, Sedum, and Echeveria are interspersed among species of Graptopetalum and show evidence of grouping according to geographical range of distribution more so than habit or floral morphology.  相似文献   
52.
目的观察血液磁极化疗法(简称血磁治疗)对糖尿病(DM)的治疗效果和对胰岛功能的影响。方法制备了四氧嘧啶DM兔模型20只,随机分为两组,即DM模型血磁治疗组及DM模型未治疗组,同时设立正常对照组10只,分别测定治疗前后空腹血糖(FPG)、糖化血红蛋白(HbA1c)、胰岛素(INS)及C-肽(C-P),并于观察期结束后处死动物取胰腺组织常规石蜡包埋切片,行HE及Mallory三色法特殊染色观察3组胰岛形态学变化。结果血磁治疗显著降低DM兔的FPG(P<0.001)。DM治疗组INS及C-P水平较治疗前明显升高(P<0.01),与未治疗组相比差异显著(P<0.05)。胰岛病理改变可见治疗组β细胞数量明显多于DM未治疗组,提示血磁疗法具有促进胰岛修复,改善胰岛功能的作用。结论血磁疗法能够促进DM时受损胰岛组织的修复,改善胰岛β细胞分泌功能,降血糖作用明显。  相似文献   
53.
The pathogenic oomycete Aphanomyces invadans is the primary etiological agent in ulcerative mycosis, an ulcerative skin disease caused by a fungus-like agent of wild and cultured fish. We developed sensitive PCR and fluorescent peptide nucleic acid in situ hybridization (FISH) assays to detect A. invadans. Laboratory-challenged killifish (Fundulus heteroclitus) were first tested to optimize and validate the assays. Skin ulcers of Atlantic menhaden (Brevoortia tyrannus) from populations found in the Pamlico and Neuse River estuaries in North Carolina were then surveyed. Results from both assays indicated that all of the lesioned menhaden (n = 50) collected in September 2004 were positive for A. invadans. Neither the FISH assay nor the PCR assay cross-reacted with other closely related oomycetes. These results provided strong evidence that A. invadans is the primary oomycete pathogen in ulcerative mycosis and demonstrated the utility of the assays. The FISH assay is the first molecular assay to provide unambiguous visual confirmation that hyphae in the ulcerated lesions were exclusively A. invadans.  相似文献   
54.
55.
Postharvest diseases cause considerable losses of harvested fruits during transportation and storage. Many yeast species have been reported as good antagonists against postharvest pear pathogens. In this work, we used a novel selection strategy that involves the isolation of yeasts from washing fluids, showing biocontrol activity against a regional Penicillium expansum strain (primary screening), originally obtained from fruit wounds after long time storage at ?1/0°C. About 26 isolates representative of the 11 yeast species identified in the 27 selected washing waters were chosen to be evaluated in a secondary screening against a regional Botrytis cinerea strain on pear wounds. Among yeasts tested, 38% showed complete control of P. expansum, but only 15% reduced the decay incidence of B. cinerea to 60–80% at ?1/0°C. These results reveal that some of the yeasts found can be biological alternatives to fungicides in the control of P. expansum and B. cinerea infections. Based on the data obtained, our strategy seems to be much more effective than the previously reported methods in obtaining successful biocontrol agents.  相似文献   
56.
The production of recombinant proteins in the milk of non-transgenic goats can be achieved by transducing the mammary gland with recombinant adenoviral vectors. However, this process involves several regulatory issues. The current study evaluates the biosafety of this production system. We present a preliminary biosafety profile based on detection of adenoviral particles in different body fluids and the antibody response after adenoviral transduction of the goat mammary gland. In addition, two methods of adenoviral inactivation in milk were tested. Although adenoviral particles were detected in the milk until day 4 after transduction, they were absent in serum, saliva, urine and feces. Anti-adenovirus antibodies were detected in serum and milk. The virus inactivation methods neutralized adenoviral particles and preserved the immunological identity of the recombinant protein. These results support the idea of a safe production of recombinant proteins using adenoviral vectors.  相似文献   
57.
Breast cancers can recur after removal of the primary tumor and treatment to eliminate remaining tumor cells. Recurrence may occur after long periods of time during which there are no clinical symptoms. Tumor cell dormancy may explain these prolonged periods of asymptomatic residual disease and treatment resistance. We generated a dormancy gene signature from published experimental models and applied it to both breast cancer cell line expression data as well as four published clinical studies of primary breast cancers. We found that estrogen receptor (ER) positive breast cell lines and primary tumors have significantly higher dormancy signature scores (P<0.0000001) than ER- cell lines and tumors. In addition, a stratified analysis combining all ER+ tumors in four studies indicated 2.1 times higher hazard of recurrence among patients whose tumors had low dormancy scores (LDS) compared to those whose tumors had high dormancy scores (HDS) (p<0.000005). The trend was shown in all four individual studies. Suppression of two dormancy genes, BHLHE41 and NR2F1, resulted in increased in vivo growth of ER positive MCF7 cells. The patient data analysis suggests that disseminated ER positive tumor cells carrying a dormancy signature are more likely to undergo prolonged dormancy before resuming metastatic growth. Furthermore, genes identified with this approach might provide insight into the mechanisms of dormancy onset and maintenance as well as dormancy models using human breast cancer cell lines.  相似文献   
58.
The role wild bird species play in the transmission and ecology of avian influenza virus (AIV) is well established; however, there are significant gaps in our understanding of the worldwide distribution of these viruses, specifically about the prevalence and/or significance of AIV in Central and South America. As part of an assessment of the ecology of AIV in Guatemala, we conducted active surveillance in wild birds on the Pacific and Atlantic coasts. Cloacal and tracheal swab samples taken from resident and migratory wild birds were collected from February 2007 to January 2010.1913 samples were collected and virus was detected by real time RT-PCR (rRT-PCR) in 28 swab samples from ducks (Anas discors). Virus isolation was attempted for these positive samples, and 15 isolates were obtained from the migratory duck species Blue-winged teal. The subtypes identified included H7N9, H11N2, H3N8, H5N3, H8N4, and H5N4. Phylogenetic analysis of the viral sequences revealed that AIV isolates are highly similar to viruses from the North American lineage suggesting that bird migration dictates the ecology of these viruses in the Guatemalan bird population.  相似文献   
59.
Phylogeographic data and divergence estimation times as well as current and past ecological niche modeling for the Mexican tulip poppy, Hunnemannia fumariifolia Sweet, were combined in order to understand its biogeographic history. Divergence times were estimated to determine if divergence occurred during the Pleistocene. Ecological niche modelling was used to determine if the last glacial maximum (LGM) was responsible for the southward movement of poppy populations into the Tehuacán-Cuicatlán Valley. Analyses were performed to detect any geographical barriers that might have caused genetic discontinuities among populations across the entire range of distribution. Current and Pleistocene ecological niche models were created for H. fumariifolia using eight environmental variables derived from temperature and precipitation. The evidence shows that divergence of the three main clades in H. fumariifolia occurred from the Early Pleistocene to Mid-Miocene. It was also found that gene flow between the populations of H. fumariifolia could have been limited by the LGM, by climate change during the Quaternary, and by the complex topography of the Sierra Madre Oriental and the Trans-Mexican Volcanic Belt. Furthermore, all of these processes may have resulted in the patchy distribution of suitable microhabitats for H. fumariifolia in its geographical range. Ecological niche models constructed using the MIROC3 model indicated that populations did not move to the north but rather that they had suitable ecological habitats in the Chihuahuan Desert, which harbored Pinus-Juniperus forests during that period.  相似文献   
60.
Fidgetin is a member of the AAA protein superfamily with important roles in mammalian development. Here we show that human Fidgetin is a potent microtubule severing and depolymerizing the enzyme used to regulate mitotic spindle architecture, dynamics and anaphase A. In vitro, recombinant human Fidgetin severs taxol-stabilized microtubules along their length and promotes depolymerization, primarily from their minus-ends. In cells, human Fidgetin targets to centrosomes, and its depletion with siRNA significantly reduces the velocity of poleward tubulin flux and anaphase A chromatid-to-pole motion. In addition, the loss of Fidgetin induces a microtubule-dependent enlargement of mitotic centrosomes and an increase in the number and length of astral microtubules. Based on these data, we propose that human Fidgetin actively suppresses microtubule growth from and attachment to centrosomes.  相似文献   
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