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41.
42.
Eveline C van Asbeck Andy IM Hoepelman Jelle Scharringa Bjorn L Herpers Jan Verhoef 《BMC microbiology》2008,8(1):229
Background
Mannose binding lectin (MBL) is an important host defence protein against opportunistic fungal pathogens. This carbohydrate-binding protein, an opsonin and lectin pathway activator, binds through multiple lectin domains to the repeating sugar arrays displayed on the surface of a wide range of clinically relevant microbial species. We investigated the contribution of MBL to antifungal innate immunity towards C. parapsilosis in vitro. 相似文献43.
Muse Oke Lester G. Carter Kenneth A. Johnson Huanting Liu Stephen A. McMahon Xuan Yan Melina Kerou Nadine D. Weikart Nadia Kadi Md. Arif Sheikh Stefan Schmelz Mark Dorward Michal Zawadzki Christopher Cozens Helen Falconer Helen Powers Ian M. Overton C. A. Johannes van Niekerk Xu Peng Prakash Patel Roger A. Garrett David Prangishvili Catherine H. Botting Peter J. Coote David T. F. Dryden Geoffrey J. Barton Ulrich Schwarz-Linek Gregory L. Challis Garry L. Taylor Malcolm F. White James H. Naismith 《Journal of structural and functional genomics》2010,11(2):167-180
The Scottish Structural Proteomics Facility was funded to develop a laboratory scale approach to high throughput structure determination. The effort was successful in that over 40 structures were determined. These structures and the methods harnessed to obtain them are reported here. This report reflects on the value of automation but also on the continued requirement for a high degree of scientific and technical expertise. The efficiency of the process poses challenges to the current paradigm of structural analysis and publication. In the 5 year period we published ten peer-reviewed papers reporting structural data arising from the pipeline. Nevertheless, the number of structures solved exceeded our ability to analyse and publish each new finding. By reporting the experimental details and depositing the structures we hope to maximize the impact of the project by allowing others to follow up the relevant biology. 相似文献
44.
45.
Dustin A. Wood Thuy-Vy D. Bui Cory T. Overton Amy G. Vandergast Michael L. Casazza Joshua M. Hull John Y. Takekawa 《Conservation Genetics》2017,18(1):131-146
Fragmentation and loss of natural habitat have important consequences for wild populations and can negatively affect long-term viability and resilience to environmental change. Salt marsh obligate species, such as those that occupy the San Francisco Bay Estuary in western North America, occupy already impaired habitats as result of human development and modifications and are highly susceptible to increased habitat loss and fragmentation due to global climate change. We examined the genetic variation of the California Ridgway’s rail (Rallus obsoletus obsoletus), a state and federally endangered species that occurs within the fragmented salt marsh of the San Francisco Bay Estuary. We genotyped 107 rails across 11 microsatellite loci and a single mitochondrial gene to estimate genetic diversity and population structure among seven salt marsh fragments and assessed demographic connectivity by inferring patterns of gene flow and migration rates. We found pronounced genetic structuring among four geographically separate genetic clusters across the San Francisco Bay. Gene flow analyses supported a stepping stone model of gene flow from south-to-north. However, contemporary gene flow among the regional embayments was low. Genetic diversity among occupied salt marshes and genetic clusters were not significantly different. We detected low effective population sizes and significantly high relatedness among individuals within salt marshes. Preserving genetic diversity and connectivity throughout the San Francisco Bay may require attention to salt marsh restoration in the Central Bay where habitat is both most limited and most fragmented. Incorporating periodic genetic sampling into the management regime may help evaluate population trends and guide long-term management priorities. 相似文献
46.
Parise EM Lilly N Kay K Dossat AM Seth R Overton JM Williams DL 《American journal of physiology. Regulatory, integrative and comparative physiology》2011,301(6):R1692-R1699
Hypothalamic orexin neurons project to the hindbrain, and 4th-ventricle intracerebroventricular (4th-icv) injection of orexin-A treatment increases food intake. We assessed the effects of hindbrain orexin-A and the orexin-1-receptor antagonist SB334867 on meal pattern in rats consuming standard chow. When injected 4th-icv shortly before dark onset, lower doses of orexin-A increased food intake over a 2-h period by increasing the size of the first meal relative to vehicle, whereas the highest dose increased food intake by causing the second meal to be taken sooner. Conversely, hindbrain SB334867 reduced food intake by decreasing the size of the first meal of the dark phase. We also examined the effects of 4th-icv orexin-A and SB334867 on locomotor activity. Only the highest dose of orexin-A increased activity, and SB334867 had no effect. In addition, hindbrain SB334867 induced c-Fos in the nucleus of the solitary tract. These data support the suggestion that endogenous hindbrain orexin-A acts to limit satiation. Both orexin-A and the pancreatic satiation hormone amylin require an intact area postrema to affect food intake, so we asked whether 4th-icv orexin-A impairs the satiating effect of peripheral amylin treatment. Amylin reduced the size of the first meal of the dark cycle when rats were pretreated with 4th-icv saline, yet amylin was ineffective after 4th-icv orexin-A pretreatment. Using double-label immunohistochemistry, we determined that some orexin-A fibers in the area postrema are located in proximity to amylin-responsive neurons. Therefore, hindbrain orexin-A may increase food intake, in part, by reducing the ability of rats to respond to amylin during a meal. 相似文献
47.
Cory T. Overton Michael L. Casazza John Y. Takekawa Donald R. Strong Marcel Holyoak 《Biological invasions》2014,16(9):1897-1914
Invasive species frequently degrade habitats, disturb ecosystem processes, and can increase the likelihood of extinction of imperiled populations. However, novel or enhanced functions provided by invading species may reduce the impact of processes that limit populations. It is important to recognize how invasive species benefit endangered species to determine overall effects on sensitive ecosystems. For example, since the 1990s, hybrid Spartina (Spartina foliosa × alterniflora) has expanded throughout South San Francisco Bay, USA, supplanting native vegetation and invading mudflats. The endangered California clapper rail (Rallus longirostris obsoletus) uses the tall, dense hybrid Spartina for cover and nesting, but the effects of hybrid Spartina on clapper rail survival was unknown. We estimated survival rates of 108 radio-marked California clapper rails in South San Francisco Bay from January 2007 to March 2010, a period of extensive hybrid Spartina eradication, with Kaplan–Meier product limit estimators. Clapper rail survival patterns were consistent with hybrid Spartina providing increased refuge cover from predators during tidal extremes which flood native vegetation, particularly during the winter when the vegetation senesces. Model averaged annual survival rates within hybrid Spartina dominated marshes before eradication (? = 0.466) were greater than the same marshes posttreatment (? = 0.275) and a marsh dominated by native vegetation (? = 0.272). However, models with and without marsh treatment as explanatory factor for survival rates had nearly equivalent support in the observed data, lending ambiguity as to whether hybrid Spartina facilitated greater survival rates than native marshland. Conservation actions to aid in recovery of this endangered species should recognize the importance of available of high tide refugia, particularly in light of invasive species eradication programs and projections of future sea-level rise. 相似文献
48.
David Dweck Marcos A. Sanchez-Gonzalez Audrey N. Chang Raul A. Dulce Crystal-Dawn Badger Andrew P. Koutnik Edda L. Ruiz Brittany Griffin Jingsheng Liang Mohamed Kabbaj Frank D. Fincham Joshua M. Hare J. Michael Overton Jose R. Pinto 《The Journal of biological chemistry》2014,289(33):23097-23111
The cardiac troponin I (cTnI) R21C (cTnI-R21C) mutation has been linked to hypertrophic cardiomyopathy and renders cTnI incapable of phosphorylation by PKA in vivo. Echocardiographic imaging of homozygous knock-in mice expressing the cTnI-R21C mutation shows that they develop hypertrophy after 12 months of age and have abnormal diastolic function that is characterized by longer filling times and impaired relaxation. Electrocardiographic analyses show that older R21C mice have elevated heart rates and reduced cardiovagal tone. Cardiac myocytes isolated from older R21C mice demonstrate that in the presence of isoproterenol, significant delays in Ca2+ decay and sarcomere relaxation occur that are not present at 6 months of age. Although isoproterenol and stepwise increases in stimulation frequency accelerate Ca2+-transient and sarcomere shortening kinetics in R21C myocytes from older mice, they are unable to attain the corresponding WT values. When R21C myocytes from older mice are treated with isoproterenol, evidence of excitation-contraction uncoupling is indicated by an elevation in diastolic calcium that is frequency-dissociated and not coupled to shorter diastolic sarcomere lengths. Myocytes from older mice have smaller Ca2+ transient amplitudes (2.3-fold) that are associated with reductions (2.9-fold) in sarcoplasmic reticulum Ca2+ content. This abnormal Ca2+ handling within the cell may be attributed to a reduction (2.4-fold) in calsequestrin expression in conjunction with an up-regulation (1.5-fold) of Na+-Ca2+ exchanger. Incubation of permeabilized cardiac fibers from R21C mice with PKA confirmed that the mutation prevents facilitation of mechanical relaxation. Altogether, these results indicate that the inability to enhance myofilament relaxation through cTnI phosphorylation predisposes the heart to abnormal diastolic function, reduced accessibility of cardiac reserves, dysautonomia, and hypertrophy. 相似文献
49.
The idea of immunological surveillance against cancer has existed for nearly 100 years but as no conclusive evidence has yet
been published the importance of the cellular immune defense in the detection and removal of incipient or existing tumors
is still a hotly debated subject. However, in order to select a relevant immunotherapeutic strategy in the treatment of cancer,
a fundamental understanding of the basic immunologic conditions under which a tumor develops and exists is a prerequisite.
Therefore, a murine model was set up that we hoped would enable us to confirm or reject the theory of immunological surveillance.
A large panel of methylcholanthrene induced tumors was established in T-cell immunodeficient nude mice and congenic normal
mice to study the influence of the immune system on developing tumors. As nude mice developed tumors fastest and with the
highest incidence, we concluded that in this model the immune system constituted a ‘tumor-suppressive factor’ delaying and
sometimes abrogating tumor growth, i.e. performing immune surveillance. Immunogenicity of the tumors was assessed by transplantation
back to normal histocompatible mice. Tumors originating from the immunodeficient nude mice turned out to be far more immunogenic
than tumors from normal mice, resulting in a high rejection rate. CD8+cytotoxic T cells were found to be indispensable for
this rejection, leading to the conclusion that the cytotoxic T cells perform immune selection in normal mice, eliminating
immunogenic tumor cell variants in the incipient tumor.
In this review, we discuss the difficulties facing immunotherapy when conclusions are drawn from the presented observations
and hypotheses. 相似文献
50.
Jacob McC. Overton 《Plant Ecology》1996,125(1):83-98
The infections of two species of mistletoes in Baja California, Mexico were investigated for spatial patterns of abundance, and for an effect of the dispersal patterns of mistletoe seeds on these spatial patterns. Mistletoe distributions were mapped and the dispersal of mistletoe seeds was observed. Most mistletoes seeds were dispersed locally to the parent tree or to nearby trees. While mistletoe distributions were highly clumped at the level of the individual tree, no spatial pattern was found above the scale of the individual tree. Infected trees were no more clumped than the overall host population, and infected trees had no more mistletoes on nearby surrounding trees than did uninfected trees. Trees showed no spatial autocorrelation in the number of mistletoes they supported. Simulations using a spatially explicit simulation model with local dispersal and stochasticity in seed dispersal, host mortality, and mistletoe mortality were used to interpret the field results. Simulation results suggest that dispersal patterns affect the overall level of variance in the number of mistletoes per tree but do not lead to spatial patterns in abundance above the scale of the tree. Thus, both simulation and field systems give the surprising result that local dispersal does not lead to spatial autocorrelation in the numbers of mistletoes per tree.Abbreviations AI =
Arroyo Inspiracion
- VSR =
Valle San Rafael 相似文献