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81.
Factors influencing germination of Bacillus subtilis spores via activation of nutrient receptors by high pressure 总被引:1,自引:0,他引:1
Black EP Koziol-Dube K Guan D Wei J Setlow B Cortezzo DE Hoover DG Setlow P 《Applied and environmental microbiology》2005,71(10):5879-5887
Different nutrient receptors varied in triggering germination of Bacillus subtilis spores with a pressure of 150 MPa, the GerA receptor being more responsive than the GerB receptor and even more responsive than the GerK receptor. This hierarchy in receptor responsiveness to pressure was the same as receptor responsiveness to a mixture of nutrients. The levels of nutrient receptors influenced rates of pressure germination, since the GerA receptor is more abundant than the GerB receptor and elevated levels of individual receptors increased spore germination by 150 MPa of pressure. However, GerB receptor variants with relaxed specificity for nutrient germinants responded as well as the GerA receptor to this pressure. Spores lacking dipicolinic acid did not germinate with this pressure, and pressure activation of the GerA receptor required covalent addition of diacylglycerol. However, pressure activation of the GerB and GerK receptors displayed only a partial (GerB) or no (GerK) diacylglycerylation requirement. These effects of receptor diacylglycerylation on pressure germination are similar to those on nutrient germination. Wild-type spores prepared at higher temperatures germinated more rapidly with a pressure of 150 MPa than spores prepared at lower temperatures; this was also true for spores with only one receptor, but receptor levels did not increase in spores made at higher temperatures. Changes in inner membrane unsaturated fatty acid levels, lethal treatment with oxidizing agents, or exposure to chemicals that inhibit nutrient germination had no major effect on spore germination by 150 MPa of pressure, except for strong inhibition by HgCl2. 相似文献
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83.
Raddassi K Kent SC Yang J Bourcier K Bradshaw EM Seyfert-Margolis V Nepom GT Kwok WW Hafler DA 《Journal of immunology (Baltimore, Md. : 1950)》2011,187(2):1039-1046
Multiple sclerosis (MS) is an autoimmune disease characterized by infiltration of pathogenic immune cells in the CNS resulting in destruction of the myelin sheath and surrounding axons. We and others have previously measured the frequency of human myelin-reactive T cells in peripheral blood. Using T cell cloning techniques, a modest increase in the frequency of myelin-reactive T cells in patients as compared with control subjects was observed. In this study, we investigated whether myelin oligodendrocyte glycoprotein (MOG)-specific T cells could be detected and their frequency was measured using DRB1*0401/MOG(97-109(107E-S)) tetramers in MS subjects and healthy controls expressing HLA class II DRB1*0401. We defined the optimal culture conditions for expansion of MOG-reactive T cells upon MOG peptide stimulation of PMBCs. MOG(97-109)-reactive CD4(+) T cells, isolated with DRB1*0401/MOG(97-109) tetramers, and after a short-term culture of PMBCs with MOG(97-109) peptides, were detected more frequently from patients with MS as compared with healthy controls. T cell clones from single cell cloning of DRB1*0401/MOG(97-109(107E-S)) tetramer(+) cells confirmed that these T cell clones were responsive to both the native and the substituted MOG peptide. These data indicate that autoantigen-specific T cells can be detected and enumerated from the blood of subjects using class II tetramers, and the frequency of MOG(97-109)-reactive T cells is greater in patients with MS as compared with healthy controls. 相似文献
84.
Huyen T. T. Phan Kasia Rybak Stefania Bertazzoni Eiko Furuki Eric Dinglasan Lee T. Hickey Richard P. Oliver Kar-Chun Tan 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2018,131(6):1223-1238
Key message
The fungus Parastagonospora nodorum causes Septoria nodorum blotch (SNB) of wheat. A genetically diverse wheat panel was used to dissect the complexity of SNB and identify novel sources of resistance.Abstract
The fungus Parastagonospora nodorum is the causal agent of Septoria nodorum blotch (SNB) of wheat. The pathosystem is mediated by multiple fungal necrotrophic effector–host sensitivity gene interactions that include SnToxA–Tsn1, SnTox1–Snn1, and SnTox3–Snn3. A P. nodorum strain lacking SnToxA, SnTox1, and SnTox3 (toxa13) retained wild-type-like ability to infect some modern wheat cultivars, suggesting evidence of other effector-mediated susceptibility gene interactions or the lack of host resistance genes. To identify genomic regions harbouring such loci, we examined a panel of 295 historic wheat accessions from the N. I. Vavilov Institute of Plant Genetic Resources in Russia, which is comprised of genetically diverse landraces and breeding lines registered from 1920 to 1990. The wheat panel was subjected to effector bioassays, infection with P. nodorum wild type (SN15) and toxa13. In general, SN15 was more virulent than toxa13. Insensitivity to all three effectors contributed significantly to resistance against SN15, but not toxa13. Genome-wide association studies using phenotypes from SN15 infection detected quantitative trait loci (QTL) on chromosomes 1BS (Snn1), 2DS, 5AS, 5BS (Snn3), 3AL, 4AL, 4BS, and 7AS. For toxa13 infection, a QTL was detected on 5AS (similar to SN15), plus two additional QTL on 2DL and 7DL. Analysis of resistance phenotypes indicated that plant breeders may have inadvertently selected for effector insensitivity from 1940 onwards. We identify accessions that can be used to develop bi-parental mapping populations to characterise resistance-associated alleles for subsequent introgression into modern bread wheat to minimise the impact of SNB.85.
Jake Dunning Foday Sahr Amanda Rojek Fiona Gannon Gail Carson Baimba Idriss Thomas Massaquoi Regina Gandi Sebatu Joseph Hassan K. Osman Timothy J. G. Brooks Andrew J. H. Simpson Ian Goodfellow Lucy Thorne Armando Arias Laura Merson Lyndsey Castle Rebecca Howell-Jones Raul Pardinaz-Solis Benjamin Hope-Gill Mauricio Ferri Jennifer Grove Mark Kowalski Kasia Stepniewska Trudie Lang John Whitehead Piero Olliaro Mohammed Samai Peter W. Horby for the RAPIDE-TKM trial team 《PLoS medicine》2016,13(4)
BackgroundTKM-130803, a small interfering RNA lipid nanoparticle product, has been developed for the treatment of Ebola virus disease (EVD), but its efficacy and safety in humans has not been evaluated.ConclusionsAdministration of TKM-130803 at a dose of 0.3 mg/kg/d by intravenous infusion to adult patients with severe EVD was not shown to improve survival when compared to historic controls.
Trial registration
Pan African Clinical Trials Registry PACTR201501000997429 相似文献86.
The responses of predators to environmental variability in the Antarctic Peninsula region have exhibited divergent patterns
owing to variation in the geographic settings of colonies and predator life-history strategies. Five breeding colonies of
Pygoscelis penguins from King George Island and Livingston Island, South Shetland Islands, Antarctica, were examined to (1) compare
the responses of sympatric congeners to recent changes in their Antarctic ecosystem and (2) assess underlying causes for such
responses. We used linear regression and correlation analyses to compare indices of abundance, recruitment, and summer breeding
performance of the Adélie (P. adeliae), gentoo (P. papua), and chinstrap penguins (P. antarctica). Breeding colonies of Adélie and chinstrap penguins have declined by roughly 50% since the mid-1970s, and recruitment indices
of Adélie penguins have declined by roughly 80%, but no such patterns are evident for gentoo penguins. Fledging success, however,
has remained stable at all breeding colonies. The different trends in abundance and recruitment indices for each species,
despite generally similar indices of summer performance, suggest that winter conditions contribute to the divergent responses
among the penguins. In particular, strong correlations between indices of penguin and krill recruitment suggest that penguins
in the South Shetland Islands may live under an increasingly krill-limited system that has disproportionate effects on the
survival of juvenile birds. 相似文献
87.
NF1 loss induces senescence during human melanocyte differentiation in an iPSC‐based model 下载免费PDF全文
Lionel Larribere Huizi Wu Daniel Novak Marta Galach Mathias Bernhardt Elias Orouji Kasia Weina Nathalie Knappe Christos Sachpekidis Ludmila Umansky Philipp Beckhove Viktor Umansky Sofie De Schepper Dieter Kaufmann Robert Ballotti Corine Bertolotto Jochen Utikal 《Pigment cell & melanoma research》2015,28(4):407-416
Neurofibromatosis type 1 (NF1) is a frequent genetic disease leading to the development of Schwann cell‐derived neurofibromas or melanocytic lesions called café‐au‐lait macules (CALMs). The molecular mechanisms involved in CALMs formation remain largely unknown. In this report, we show for the first time pathophysiological mechanisms of abnormal melanocyte differentiation in a human NF1+/?‐induced pluripotent stem cell (iPSC)‐based model. We demonstrate that NF1 patient‐derived fibroblasts can be successfully reprogrammed in NF1+/? iPSCs with active RAS signaling and that NF1 loss induces senescence during melanocyte differentiation as well as in patient's‐derived CALMs, revealing a new role for NF1 in the melanocyte lineage. 相似文献
88.
Ciara OMeara Emilie Henrotte Kasia Kupisiewicz Catherine Latour Marleen Broekhuijse Agnes Camus Lucie Gavin-Plagne Eli Sellem 《Animal Reproduction》2022,19(1)
Semen motility is the most widely recognized semen quality parameter used by Artificial Insemination (AI) centers. With the increasing worldwide export of semen between AI centers there is an increasing need for standardized motility assessment methods. Computer-Assisted Sperm Analysis (CASA) technology is thought to provide an objective motility evaluation; however, results can still vary between laboratories. The aim of present study was to verify the impact of different setting values of the CASA IVOS II on motility, concentration, and morphology of bovine semen samples frozen in an extender with or without egg yolk and then decide on optimal settings for a further validation step across AI centers. Semen straws from 30 different bulls were analyzed using IVOS II with twelve modified settings. No significant changes were observed in semen concentration, percentage of motile sperm or kinetic results for either extender type. However, increasing settings for both STR and VAP progressive (%) from Low, Medium, and High cut-off values significantly (p<0.05) reduced the percentage of detected progressive spermatozoa, in egg yolk extender from 49.5±15.2, 37.2±11.9 to 11.9±5.3%, and in clear extender from 51.9±9.1, 35.8±7.3 to 10.0±2.4%, respectively. In clear extender only, the modification of droplet proximal head length significantly affected the detection of normal sperm percentages (88.0± 4.7 to 95.0±0.6 and 96.0±0.6%) and of the percentage of detected proximal droplets (12.2±4.7, 2.5±2.7 to 0.6±0.2%) for Low, Medium and High values respectively (p<0.05). The identification of sensitivity within the CASA system to changes in set parameters then led to the determination of an optimal IVOS II setting. The existing variability among centers for these phenotypes was reduced when the standardized settings were applied across different CASA units. The results clearly show the importance of applied settings for the final CASA results and emphasize the need for standardized settings to obtain comparable data. 相似文献
89.
Caws M Thwaites G Dunstan S Hawn TR Lan NT Thuong NT Stepniewska K Huyen MN Bang ND Loc TH Gagneux S van Soolingen D Kremer K van der Sande M Small P Anh PT Chinh NT Quy HT Duyen NT Tho DQ Hieu NT Torok E Hien TT Dung NH Nhu NT Duy PM van Vinh Chau N Farrar J 《PLoS pathogens》2008,4(3):e1000034
The factors that govern the development of tuberculosis disease are incompletely understood. We hypothesized that some strains of Mycobacterium tuberculosis (M. tuberculosis) are more capable of causing disseminated disease than others and may be associated with polymorphisms in host genes responsible for the innate immune response to infection. We compared the host and bacterial genotype in 187 Vietnamese adults with tuberculous meningitis (TBM) and 237 Vietnamese adults with uncomplicated pulmonary tuberculosis. The host genotype of tuberculosis cases was also compared with the genotype of 392 cord blood controls from the same population. Isolates of M. tuberculosis were genotyped by large sequence polymorphisms. The hosts were defined by polymorphisms in genes encoding Toll-interleukin 1 receptor domain containing adaptor protein (TIRAP) and Toll-like receptor-2 (TLR-2). We found a significant protective association between the Euro-American lineage of M. tuberculosis and pulmonary rather than meningeal tuberculosis (Odds ratio (OR) for causing TBM 0.395, 95% confidence intervals (C.I.) 0.193-0.806, P = 0.009), suggesting these strains are less capable of extra-pulmonary dissemination than others in the study population. We also found that individuals with the C allele of TLR-2 T597C allele were more likely to have tuberculosis caused by the East-Asian/Beijing genotype (OR = 1.57 [95% C.I. 1.15-2.15]) than other individuals. The study provides evidence that M. tuberculosis genotype influences clinical disease phenotype and demonstrates, for the first time, a significant interaction between host and bacterial genotypes and the development of tuberculosis. 相似文献
90.
Ann M. A. Harding Keith A. Hobson Wojciech Walkusz Kasia Dmoch Nina J. Karnovsky Thomas I. Van Pelt Jan T. Lifjeld 《Polar Biology》2008,31(6):725-733
The little auk (Alle alle), a small and abundant planktivorous seabird that breeds in the high Arctic, has the potential to be used as a monitor of
the composition and abundance of lower trophic-level zooplankton. We investigated age- and sex-related sources of variation
in diet and stable isotope (δ13C and δ15N) values of little auks breeding in Spitsbergen during the summer of 2002 to evaluate this possibility. Stable isotope profiles
of both adult and chick blood changed over the breeding season, with blood δ15N values increasing and δ13C values decreasing. This could represent a switch to higher trophic-level prey derived from more pelagic sources. However,
while chick blood δ13C values followed those values in their meals, this was not the case for blood δ15N values, suggesting additional physiological mechanisms influencing blood δ15N values in growing chicks. Chicks had consistently lower δ15N values than their parents, which may indicate they were being fed on lower trophic-level prey items or may alternatively
reflect complexities in chick blood δ15N values through the growth period. These results have several important implications for use of stable isotope analysis as
a tool to detect changes in seabird diet and availability of lower trophic-level prey in high-Arctic marine environments.
Until physiological aspects of stable isotope discrimination are well understood, we caution against using chicks of this
seabird as any form of isotopic monitor. 相似文献