A common fold mediates vertebrate defense and bacterial attack     

Rosado CJ  Buckle AM  Law RH  Butcher RE  Kan WT  Bird CH  Ung K  Browne KA  Baran K  Bashtannyk-Puhalovich TA  Faux NG  Wong W  Porter CJ  Pike RN  Ellisdon AM  Pearce MC  Bottomley SP  Emsley J  Smith AI  Rossjohn J  Hartland EL  Voskoboinik I  Trapani JA  Bird PI  Dunstone MA  Whisstock JC 《Science (New York, N.Y.)》2007,317(5844):1548-1551

Proteins containing membrane attack complex/perforin (MACPF) domains play important roles in vertebrate immunity, embryonic development, and neural-cell migration. In vertebrates, the ninth component of complement and perforin form oligomeric pores that lyse bacteria and kill virus-infected cells, respectively. However, the mechanism of MACPF function is unknown. We determined the crystal structure of a bacterial MACPF protein, Plu-MACPF from Photorhabdus luminescens, to 2.0 angstrom resolution. The MACPF domain reveals structural similarity with poreforming cholesterol-dependent cytolysins (CDCs) from Gram-positive bacteria. This suggests that lytic MACPF proteins may use a CDC-like mechanism to form pores and disrupt cell membranes. Sequence similarity between bacterial and vertebrate MACPF domains suggests that the fold of the CDCs, a family of proteins important for bacterial pathogenesis, is probably used by vertebrates for defense against infection.  相似文献   

Ultraviolet Emissions Observed near Venus from Mariner V     

Barth CA  Pearce JB  Kelly KK  Wallace L  Fastie WG 《Science (New York, N.Y.)》1967,158(3809):1675-1678

A Lyman-alpha airglow of atomic hydrogen measured in the outer atmosphere of Venus showed that atomic hydrogen is present. The variation as a function of height indicates that the temperature of the upper atmosphere of Venus is lower than that of Earth. An ultraviolet airglow of atomic oxygen was not found. An ultraviolet nightglow was observed on the dark limb.  相似文献   

TRYPARSAMIDE IN THE CONTROL OF AFRICAN SLEEPING SICKNESS     

Pearce L 《Science (New York, N.Y.)》1939,90(2324):39-40

  相似文献   

AN ANALYSIS OF THE MEDICAL GROUP IN CATTELL'S THOUSAND LEADING MEN OF SCIENCE     

Pearce RM 《Science (New York, N.Y.)》1915,42(1078):264-278

  相似文献   

Effects of resident rhizobial communities and soil type on the effective nodulation of pulse legumes     

J.F Slattery  D.J Pearce  W.J Slattery 《Soil biology & biochemistry》2004,36(8):1339-1346

Communities of resident rhizobia capable of effective nodulation of pulse crops were found to vary considerably over a range of soil environments. These populations from soils at 50 sites in Southern Australia were evaluated for nitrogen fixing effectiveness in association with Pisum sativum, Vicia faba, Lens culinaris, Vicia sativa, Cicer arietinum and Lupinus angustifolius. The values for nitrogen fixing effectiveness could be related to soil pH as determined by soil type and location. It was found that 33% of paddocks had sufficient resident populations of Rhizobium leguminosarum bv viciae for effective nodulation of faba bean, 54% for lentils, 55% for field pea and 66% for the effective nodulation of the vetch host plant. Mesorhizobium cicer populations were very low with only 7% of paddocks surveyed having sufficient resident populations for effective nodulation. Low resident rhizobial populations (<10 rhizobia g⁻¹ soil) of R. leguminosarum bv viciae and M. cicer were found in acid soil conditions. In contrast, Bradyrhizobium populations increased as soil pH decreased. Inoculation increased faba bean yields from 0.34 to 4.4 t ha⁻¹ and from 0.47 to 2.37 t ha⁻¹ for chickpeas on acid soils. On alkaline soils, where resident populations were large there was no consistent response to inoculation. Observations at experimental field sites confirmed the findings from the survey data, stressing the importance of rhizobial inoculation, especially on the acid soils in south-eastern Australia.  相似文献   

Effect of temperature on somatic growth and survivorship of early post-settled green sea urchins, Strongylocentrotus droebachiensis (Müller)     

Christopher M Pearce  Sean W Williams  Fu Yuan  John D Castell  & Shawn M C Robinson 《Aquaculture Research》2005,36(6):600-609

A laboratory experiment was run for 171 days to assess growth and survivorship of recently settled juveniles of the green sea urchin, Strongylocentrotus droebachiensis (Müller), reared at five temperatures: 4.7±0.8, 9.0±1.1, 12.9±1.1, 16.0±1.5 and 19.7±1.3°C (mean±SD, n=7942). Individual sea urchins were housed separately in PVC pots with Nitex mesh bottoms (10 per tank and five replicate tanks per temperature treatment) and fed a combination of benthic diatoms and macroalgae (Porphyra sp.). The test diameter of each urchin was measured and survivorship recorded on a monthly basis. Mean (±SE) test diameter of all individuals at the beginning of the experiment was 2.41±0.03 mm (n=250). At the end of the experiment, mean test diameter (±SE) was significantly larger at 9.0°C (8.46±0.06 mm) and 12.9°C (8.20±0.25 mm) than at 4.7°C (7.27±0.05 mm), 16.0°C (6.72±0.17 mm) and 19.7°C (2.65±0.24 mm) and significantly larger at 4.7 and 16.0°C than at 19.7°C. When growth was expressed as a per cent increase in test diameter from the start of the experiment, however, there were no significant pair‐wise differences among 4.7, 9.0, 12.9 and 16.0°C treatments at the end of the experiment, but all these treatments were significantly greater than at 19.7°C. Mean per cent survivorship (±SE) at the end of the experiment for the various temperature treatments was 76.0±6.0%, 90.0±5.5%, 100.0±0.0%, 98.0±2.0% and 26.0±11.2% at 4.7, 9.0, 12.9, 16.0 and 19.7°C respectively. Per cent survivorship was significantly greater at 4.7, 9.0, 12.9 and 16.0°C than at 19.7°C and significantly greater at 12.9 and 16.0°C than at 4.7°C. Mean area increase of urchins per replicate tank at the end of the experiment – taking into account both test diameter growth and survivorship – was significantly larger at 9.0 and 12.9°C than at 4.7, 16.0 and 19.7°C, and significantly larger at 4.7 and 16.0°C than at 19.7°C. The results of this study suggest that young juveniles of S. droebachiensis should be reared at 9–13°C in order to optimize production for aquaculture.  相似文献   

Integrating contact network structure into tuberculosis epidemiology in meerkats in South Africa: Implications for control     

Drewe JA  Eames KT  Madden JR  Pearce GP 《Preventive veterinary medicine》2011,101(1-2):113-120

Empirical studies that integrate information on host contact patterns with infectious disease transmission over time are rare. The aims of this study were to determine the relative importance of intra-group social interactions in the transmission of tuberculosis (TB; Mycobacterium bovis infection) in a population of wild meerkats (Suricata suricatta) in South Africa, and to use this information to propose an evidence-based intervention strategy to manage this disease. Detailed behavioural observations of all members of eight meerkat groups (n=134 individuals) were made over 24 months from January 2006 to December 2007. Social network analysis of three types of interaction (aggression, foraging competitions and grooming) revealed social structure to be very stable over time. Clustering of interactions was positively correlated with group size for both aggression (r=0.73) and grooming interactions (r=0.71), suggesting that infections may spread locally within clusters of interacting individuals but be limited from infecting all members of large groups by an apparent threshold in connections between different clusters. Repeated biological sampling every three months of all members of one social group (n=37 meerkats) was undertaken to quantify individual changes in M. bovis infection status. These empirical data were used to construct a dynamic network model of TB transmission within a meerkat group. The results indicated that grooming (both giving and receiving) was more likely than aggression to be correlated with M. bovis transmission and that groomers were at higher risk of infection than groomees. Intervention strategies for managing TB in meerkats that focus on those individuals engaging in the highest amount of grooming are therefore proposed.  相似文献   

Analytical Diagnostic Peritoneal Lavage in the Diagnosis of Intra-abdominal Injury     

Thompson DC  Pearce WJ  Longerbeam JK 《Veterinary surgery : VS》1985,14(4):327-327

  相似文献   

Management of bilateral uveitis in a Toxoplasma gondii-seropositive cat with histopathologic evidence of fungal panuveitis     

Pearce J  Giuliano EA  Galle LE  Klauss G  Ota J  Moore CP 《Veterinary ophthalmology》2007,10(4):216-221

A 5-year-old, neutered male Domestic Short-haired cat was referred with a 5-month history of anterior uveitis and cataract in the right eye. Clinical examination confirmed anterior uveitis and immature cataract in the right eye and chorioretinitis in the left eye. Ocular ultrasound showed a retinal detachment in the right eye. Diagnostic testing revealed elevated serum titers for Toxoplasma gondii. Anterior uveitis in the right eye and chorioretinitis in the left eye progressed, resulting in blindness despite a 21-day course of clindamycin and aggressive topical medical management of uveitis. The right eye was enucleated and histopathologic evaluation of the globe revealed panuveitis and multiple organisms morphologically consistent with Histoplasma capsulatum. Systemic treatment with itraconazole was initiated. Vision returned after 3 months of treatment and complete resolution of the retinal hemorrhages with formation of a flat chorioretinal scar was noted after 6 months of therapy. Itraconazole was discontinued 7 months after starting therapy, at which time the funduscopic appearance of the chorioretinal scar had remained static for 1 month. The cat has remained visual without evidence of disease progression for 6 months following discontinuation of itraconazole.  相似文献   

Client knowledge,attitudes and practices regarding zoonoses: a metropolitan experience          下载免费PDF全文

SG Steele  SM Mor 《Australian veterinary journal》2015,93(12):439-444

  相似文献