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71.
In this study we construct a phylogenetic hypothesis for the relatedness among disjunct subspecies of Cyclamen repandum and its two allopatric congeners, C. creticum and C. balearicum in order to examine the evolutionary divergence of currently isolated populations across the western Mediterranean. The most
parsimonious phylogenetic tree obtained from sequencing the cpDNA trnL (UAA) intron suggests a major phylogeographic divide in southern Greece between two clades. The first clade comprises samples
of C. repandum subsp. peloponnesiacum (from the Peloponnese) and C. creticum (from Crete). The second comprises samples of C. repandum subsp. repandum (from Croatia, Italy, southern France, Corsica, Sardinia and Sicily), C. repandum subsp. rhodense (from Rhodes and Kos) and C. balearicum (from the Balearic Islands and southern France). These data suggest that C. creticum has evolved in allopatry from C. repandum subsp. peloponnesiacum and that C. balearicum and C. repandum ssp. rhodense have diverged from C. repandum subsp. repandum at its western and eastern distribution limits. At one small site on Corsica, a population of C. repandum may have introgressed with relictual populations of C. balearicum. These divergence patterns illustrate how a phylogenetic perspective can be used to better understand the evolution of endemism
in the Mediterranean flora.
Received February 19, 2001 Accepted August 22, 2001 相似文献
72.
Abhishek Chatterjee Celia Caballero-Franco Dannika Bakker Stephanie Totten Armando Jardim 《The Journal of biological chemistry》2015,290(42):25579-25594
Enterohemorrhagic Escherichia coli is a causative agent of gastrointestinal and diarrheal diseases. Pathogenesis associated with enterohemorrhagic E. coli involves direct delivery of virulence factors from the bacteria into epithelial cell cytosol via a syringe-like organelle known as the type III secretion system. The type III secretion system protein EspD is a critical factor required for formation of a translocation pore on the host cell membrane. Here, we show that recombinant EspD spontaneously integrates into large unilamellar vesicle (LUV) lipid bilayers; however, pore formation required incorporation of anionic phospholipids such as phosphatidylserine and an acidic pH. Leakage assays performed with fluorescent dextrans confirmed that EspD formed a structure with an inner diameter of ∼2.5 nm. Protease mapping indicated that the two transmembrane helical hairpin of EspD penetrated the lipid layer positioning the N- and C-terminal domains on the extralumenal surface of LUVs. Finally, a combination of glutaraldehyde cross-linking and rate zonal centrifugation suggested that EspD in LUV membranes forms an ∼280–320-kDa oligomeric structure consisting of ∼6–7 subunits. 相似文献
73.
74.
Horim Lee 《Molecules and cells》2015,38(7):651-656
Plant growth and development are coordinately orchestrated by environmental cues and phytohormones. Light acts as a key environmental factor for fundamental plant growth and physiology through photosensory phytochromes and underlying molecular mechanisms. Although phytochromes are known to possess serine/threonine protein kinase activities, whether they trigger a signal transduction pathway via an intracellular protein kinase network remains unknown. In analyses of mitogen-activated protein kinase kinase (MAPKK, also called MKK) mutants, the mkk3 mutant has shown both a hypersensitive response in plant hormone gibberellin (GA) and a less sensitive response in red light signaling. Surprisingly, light-induced MAPK activation in wild-type (WT) seedlings and constitutive MAPK phosphorylation in dark-grown mkk3 mutant seedlings have also been found, respectively. Therefore, this study suggests that MKK3 acts in negative regulation in darkness and in light-induced MAPK activation during dark-light transition. 相似文献
75.
76.
Nia J. Bryant Robert C. Piper Lois S. Weisman Tom H. Stevens 《The Journal of cell biology》1998,142(3):651-663
A large number of trafficking steps occur between the last compartment of the Golgi apparatus (TGN) and the vacuole of the yeast Saccharomyces cerevisiae. To date, two intracellular routes from the TGN to the vacuole have been identified. Carboxypeptidase Y (CPY) travels through a prevacuolar/endosomal compartment (PVC), and subsequently on to the vacuole, while alkaline phosphatase (ALP) bypasses this compartment to reach the same organelle. Proteins resident to the TGN achieve their localization despite a continuous flux of traffic by continually being retrieved from the distal PVC by virtue of an aromatic amino acid–containing sorting motif. In this study we report that a hybrid protein based on ALP and containing this retrieval motif reaches the PVC not by following the CPY sorting pathway, but instead by signal-dependent retrograde transport from the vacuole, an organelle previously thought of as a terminal compartment. In addition, we show that a mutation in VAC7, a gene previously identified as being required for vacuolar inheritance, blocks this trafficking step. Finally we show that Vti1p, a v-SNARE required for the delivery of both CPY and ALP to the vacuole, uses retrograde transport out of the vacuole as part of its normal cellular itinerary. 相似文献
77.
Sophie J. Milward Natalie Sebanz 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2016,371(1686)
This opinion piece offers a commentary on the four papers that address the theme of the development of self and other understanding with a view to highlighting the important contribution of developmental research to understanding of mechanisms of social cognition. We discuss potential mechanisms linking self–other distinction and empathy, implications for grouping motor, affective and cognitive domains under a single mechanism, applications of these accounts for joint action and finally consider self–other distinction in group versus dyadic settings. 相似文献
78.
BackgroundComparative evidence on the burden, trend, and risk factors of cancer is limited. Using data from the Global Burden of Disease (GBD) study, we aimed to assess cancer burden – incidence, prevalence, mortality, disability-adjusted life years (DALYs) – and attributable risk factors for Australia between 1990 and 2015, and to compare them with those of 34 members of the Organisation for Economic Co-operation and Development (OECD).MethodsThe general GBD cancer estimation methods were used with data input from vital registration systems and cancer registries. A comparative risk assessment approach was used to estimate the population-attributable fractions due to risk factors.ResultsIn 2015 there were 198,880 (95% uncertainty interval [UI]: 183,908–217,365) estimated incident cancer cases and 47,562 (95% UI: 46,061–49,004) cancer deaths in Australia. Twenty-nine percent (95% UI: 28.2–29.8) of total deaths and 17.0% (95% UI: 15.0–19.1) of DALYs were caused by cancer in Australia in 2015. Cancers of the trachea, bronchus and lung, colon and rectum, and prostate were the most common causes of cancer deaths. Thirty-six percent (95% UI: 33.1–37.9) of all cancer deaths were attributable to behavioral risks. The age-standardized cancer incidence rate (ASIR) increased between 1990 and 2015, while the age-standardized cancer death rate (ASDR) decreased over the same period. In 2015, compared to 34 other OECD countries Australia ranked first (highest) and 24th based on ASIR and ASDR, respectively.ConclusionThe incidence of cancer has increased over 25 years, and behavioral risks are responsible for a large proportion of cancer deaths. Scaling up of prevention (using strategies targeting cancer risk factors), early detection, and treatment of cancer is required to effectively address this growing health challenge. 相似文献
79.
《Bioorganic & medicinal chemistry》2019,27(21):115089
Colorectal carcinoma (CRC) is one of the most common cancers with high metastatic potential, explaining why identifying new drug candidates that inhibit tumour metastasis is an urgent need. The aim of this study was to evaluate the biological activities of pectolinarigenin (PEC, a natural flavonoid present in Cirsium chanroenicum) in CRC in vitro and in vivo and to determine its underlying mechanism of action. Here, we observed that treatment with PEC could inhibit cell viability and induce apoptosis in cancer cells in a concentration- and time-dependent manner. The occurrence of apoptosis was associated with activation of caspase-3 and Bax and decreased expression of Bcl-2. In addition, PEC markedly impaired CRC cell migration and invasion by downregulating the expression of matrix metalloproteinase (MMP-9) and phosphorylated-Stat3Tyr705. Moreover, our studies showed that PEC inhibited abdominal metastasis models of murine colorectal cancer. In addition, histological and immunohistochemical analyses revealed a decrease in Ki67-positive cells, MMP9-positive cells and p-Stat3Tyr705 cells upon treatment with PEC compared to control samples. Furthermore, PEC reduced the number of myeloid-derived suppressor cells (MDSCs) in the blood and tumours, which was accompanied by the increased infiltration of CD8+T cells in the blood. Taken together, our findings suggested that PEC could be used as a natural drug to inhibit CRC metastasis. 相似文献
80.
Neurofilament Protein Phosphorylation in Spinal Cord of Experimentally Diabetic Rats 总被引:1,自引:1,他引:0
This study was designed to determine if the known decrease in slow axonal transport of proteins in the sciatic nerve of experimentally diabetic rats is related to altered phosphorylation of neurofilament proteins (NFPs). Rats were rendered diabetic with 50 mg/kg of streptozotocin, i.p. At 3 and 6 weeks later, NFPs were prepared from spinal cord. The in vivo phosphorylation state of NFPs was examined by using phosphate-dependent (RT97) and -independent (RMd09) antibodies against high-molecular-mass NFPs on Western blots. Neurofilament-associated kinase activity was also measured in vitro by incubation of NFPs with [32P]ATP. Phosphorylation of all three NFPs (high, medium, and low molecular mass) occurred, as confirmed by gel electrophoresis and autoradiography. At 30 min of incubation, protein-bound radioactivity in NFPs from diabetic animals was reduced to 86.7 +/- 3.4 and 54.3 +/- 19.6% of that in nondiabetic animals at 3 and 6 weeks of diabetes, respectively (p less than 0.001 and p less than 0.05, respectively). NFPs were also incubated with acid phosphatase and rephosphorylated. Results showed that the increased in vivo phosphorylation contributed to the decreased in vitro phosphorylation. Extraction of protein kinases and addition back to the NFPs revealed, in addition, a reduced activity in the diabetic animals of the protein kinases measured in vitro. 相似文献