Experimental studies of the role of the little raven (Corvus mellori) in surveillance for West Nile virus in Australia     

J Bingham  RA Lunt  DJ Green  KR Davies  V Stevens  FYK Wong 《Australian veterinary journal》2010,88(6):204-210

Objective To study the potential role of an Australian corvid, the little raven (Corvus mellori), in the surveillance for exotic West Nile virus (WNV) in Australia. Method In a series of trials, little ravens were infected with WNV (strain 4132 New York 1999) and Kunjin virus (strain K42886) by the intramuscular route. They were observed for 20 days during which blood and swab samples were taken for virus isolation. Tissue samples were taken from ravens humanely killed during the acute infection period, and at the termination of the trials, for virus isolation, histopathology and immunohistochemistry. Results Ravens infected with WNV became mildly ill, but all recovered and seroconverted. Blood virus titres peaked around 3 to 4 days after inoculation at levels between 10^3.0 to 10^7.5 plaque forming units/mL. Virus or viral antigen was detected in spleen, liver, lung, kidney, intestine, testis and ovary by virus isolation and/or immunohistochemistry. WNV was detected in oral and cloacal swabs from 2 to 7 days post inoculation. The molecular and pathogenic characteristics of the inocula were consistent with them being of high virulence, as expected for this isolate. Ravens infected with Kunjin virus developed viraemia and seroconverted, although they did not develop disease. Conclusions Little ravens do not develop severe disease in response to virulent WNV infection and for this reason may not be important sentinel hosts in the event of an outbreak of WNV, as in North America. However, as they have relatively high viraemias, they may be able to support virus cycles.  相似文献   

Leukotrienes Affect Secretory Function of Ovarian Cells In Vitro*     

AJ Korzekwa  TJ Acosta  M Miklewicz  K Okuda  SH Lee  DJ Skarzynski 《Reproduction in domestic animals》2010,45(6):e288-e296

The aim of this study was to determine which cells are the source of production and target for leukotriene (LTs) action within the bovine ovary. Luteal (CL, days 14–16 of the oestrous cycle), steroidogenic cells (LSC) and endothelial cells (LEC) of the bovine corpus luteum (CL), and granulosa cells (GC) were isolated enzymatically, cultured in a monolayer and incubated with LTC₄, LTB₄, Azelastine (an antagonist of LTC₄) or Dapsone (an antagonist of LTB₄). Then cells were collected for determination of mRNA expression for LT receptors (LTRs) and 5‐lipoxygenase (5‐LO) by real time RT‐PCR, and media were collected for determination of prostaglandin (PG)E₂, F_2α, progesterone (P4; LSC only), endothelin‐1 (ET‐1; LEC only) and 17‐β oestradiol (E2; GC only). The greatest mRNA expression for LTR‐II and 5‐LO were found in LEC, whereas LTR‐I mRNA expression did not differ among cell types. The level of PGE₂ increased after LTs treatment in each type of ovarian cell, excluding LTC₄ treatment in LEC. The secretion of PGF_2α was also increased by LTs, but decreased after LTB₄ treatment of LSC. In GC cultures, both LTs stimulated E2 secretion; in LEC cultures, LTB₄ stimulated whereas LTC₄ inhibited P4 secretion; in LEC cultures, LTC₄ stimulated but LTB₄ inhibited ET‐1 secretion. The results show that LTs are produced locally and are involved in PGs production/secretion in all examined cells (LSC, LEC and GC) of bovine ovary. Leukotriene treatment modulate secretion of E2, by GC, P4 by LSC and ET‐1 by LEC, which indicates that LTs are involved in regulation of ovarian secretory functions.  相似文献   

Erysipelas in malleefowl     

DJ BLYDE  R WOODS 《Australian veterinary journal》1999,77(7):434-435

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Micromechanical "Trampoline" magnetometers for use in large pulsed magnetic fields     

V Aksyuk  FF Balakirev  GS Boebinger  PL Gammel  RC Haddon  DJ Bishop 《Science (New York, N.Y.)》1998,280(5364):720-722

A silicon micromechanical magnetometer was constructed and successfully used in 60-tesla pulsed magnetic fields of less than 100-millisecond duration. The device is small, inexpensive to fabricate, and easy to use. It features a fast mechanical response (up to 50,000 hertz) and extremely high sensitivity yet is relatively robust against electrical and mechanical noise. Quantum oscillations in the magnetization of a 1-microgram sample of an organic superconductor, kappa-[bis(ethylenedithio)tetrathiafulvalene]2Cu(NCS)2, have been observed with this device.  相似文献   

Major compositional units of the moon: lunar prospector thermal and fast neutrons   总被引：2，自引：0，他引：2  

WC Feldman  BL Barraclough  S Maurice  RC Elphic  DJ Lawrence  DR Thomsen  AB Binder 《Science (New York, N.Y.)》1998,281(5382):1489-1493

Global maps of thermal and fast neutron fluxes from the moon suggest three end-member compositional units. A high thermal and low fast neutron flux unit correlates with the lunar highlands and is consistent with feldspathic rocks. The South Pole-Aitken basin and a strip that surrounds the nearside maria have intermediate thermal and fast neutron flux levels, consistent with more mafic rocks. There appears to be a smooth transition between the most mafic and feldspathic compositions, which correspond to low and high surface altitudes, respectively. The maria show low thermal and high fast neutron fluxes, consistent with basaltic rocks.  相似文献   

Platinum catalysts for the high-yield oxidation of methane to a methanol derivative   总被引：1，自引：0，他引：1  

RA Periana  DJ Taube  S Gamble  H Taube  T Satoh  H Fujii 《Science (New York, N.Y.)》1998,280(5363):560-564

Platinum catalysts are reported for the direct, low-temperature, oxidative conversion of methane to a methanol derivative at greater than 70 percent one-pass yield based on methane. The catalysts are platinum complexes derived from the bidiazine ligand family that are stable, active, and selective for the oxidation of a carbon-hydrogen bond of methane to produce methyl esters. Mechanistic studies show that platinum(II) is the most active oxidation state of platinum for reaction with methane, and are consistent with reaction proceeding through carbon-hydrogen bond activation of methane to generate a platinum-methyl intermediate that is oxidized to generate the methyl ester product.  相似文献   

Lunar Fe and Ti abundances: comparison of lunar prospector and clementine data   总被引：3，自引：0，他引：3  

RC Elphic  DJ Lawrence  WC Feldman  BL Barraclough  S Maurice  AB Binder  PG Lucey 《Science (New York, N.Y.)》1998,281(5382):1493-1496

The Lunar Prospector neutron spectrometer data correlate well with iron and titanium abundances obtained through analysis of Clementine spectral reflectance data. With the iron and titanium dependence removed, the neutron spectrometer data also reveal regions with enhanced amounts of gadolinium and samarium, incompatible rare earth elements that are enriched in the final phases of magma crystallization. These regions are found mainly around the ramparts of the Imbrium impact basin but not around the other basins, including the much larger and deeper South Pole-Aitken basin. This result confirms the compositional uniqueness of the surface and interior of the Imbrium region.  相似文献   

Optimum use of available residue data in the estimation of dietary intake of pesticides     

DJ Hamilton  PT Holland  B Ohlin  WJ Murray  A Ambrus  GC de Baptista  J Kovacicova 《Pest management science》1999,55(2):220-221

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Rings versus knife for docking and castration of lambs     

DJ MELLOR  RJ HOLMES † 《Australian veterinary journal》1988,65(12):403-404

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A serological survey to determine the prevalence of infection with Treponema hyodysenteriae in Western Australia     

JRL MHOMA  DJ HAMPSON  ID ROBERTSON 《Australian veterinary journal》1992,69(4):81-84

A serological survey to detect antibody titres against Treponema hyodysenteriae was conducted on pigs from 106 herds in Western Australia. Titres indicating a positive result in the tests were determined by examining 400 sera from 4 herds known to be free of swine dysentery, and sera from immunised or experimentally infected pigs. Samples of serum from 40 bacon-weight pigs from each of the 106 herds were then collected at 2 abattoirs. Each serum was tested in enzyme-linked immunosorbent assays (ELISA) against the lipopolysaccharide of T hyodysenteriae of serogroups A, B and E, respectively. To assist in evaluating the test, 19 herds were resampled and retested, and faecal samples from 17 herds were cultured for T hyodysenteriae. Thirty-five of the 106 herds (33%) had serological evidence of infection when only one batch of sera from each herd was tested. The ELISA to detect T hyodysenteriae infection in herds using 40 sera was estimated as having a sensitivity of 77.3% and a specificity of 81.8% based on the owners' opinion of their herds disease status. Prevalence of infection within herds ranged from 2.5% to 47.5%, with a mean of 18%.  相似文献