IgM responses in chicken serum to live and inactivated infectious bronchitis virus vaccines.     

N R Martins  A P Mockett  A D Barrett  J K Cook 《Avian diseases》1991,35(3):470-475

Intramuscular (i.m.) administration of infectious bronchitis virus (IBV) oil-emulsion vaccine (OEV) to IBV-primed or unprimed chickens resulted in the production of zero or minimal concentrations of IBV-specific IgM in the serum, as measured by enzyme-linked immunosorbent assay of gel chromatography fractions. Live-attenuated infectious bronchitis (IB) vaccine given i.m. or by eyedrop stimulated the production of IBV-specific IgM in similar amounts following inoculation by both routes. These levels were comparable to those found in earlier studies following intranasal inoculation with a virulent strain of IBV and confirm that the detection of IBV-specific IgM is a valuable aid to the diagnosis of recent infection. As expected, administration of live-attenuated IB vaccines i.m. or by eyedrop protected the respiratory tract against challenge with virulent virus 24 days later; however, OEV given i.m. did not.  相似文献   

Efficacy of a cold-adapted, intranasal, equine influenza vaccine: challenge trials.     

H G Townsend  S J Penner  T C Watts  A Cook  J Bogdan  D M Haines  S Griffin  T Chambers  R E Holland  P Whitaker-Dowling  J S Youngner  R W Sebring 《Equine veterinary journal》2001,33(7):637-643

A randomised, controlled, double-blind, influenza virus, aerosol challenge of horses was undertaken to determine the efficacy of a cold-adapted, temperature sensitive, modified-live virus, intranasal, equine influenza vaccine. Ninety 11-month-old influenza-na?ve foals were assigned randomly to 3 groups (20 vaccinates and 10 controls per group) and challenged 5 weeks, 6 and 12 months after a single vaccination. Challenges were performed on Day 0 in a plastic-lined chamber. Between Days 1 and 10, animals were examined daily for evidence of clinical signs of influenza. Nasal swabs for virus isolation were obtained on Day 1 and Days 1 to 8 and blood samples for serology were collected on Days 1, 7 and 14. There was no adverse response to vaccination in any animal. Following challenge at 5 weeks and 6 months, vaccinates had significantly lower clinical scores (P = 0.0001 and 0.005, respectively), experienced smaller increases in rectal temperature (P = 0.0008 and 0.0007, respectively) and shed less virus (P<0.0001 and P = 0.03, respectively) over fewer days (P<0.0001 and P = 0.002, respectively) than did the controls. After the 12 month challenge, rectal temperatures (P = 0.006) as well as the duration (P = 0.03) and concentration of virus shed (P = 0.04) were significantly reduced among vaccinated animals. The results of this study showed that 6 months after a single dose of vaccine the duration and severity of clinical signs were markedly reduced amongst vaccinated animals exposed to a severe live-virus challenge. Appropriate use of this vaccine should lead to a marked reduction in the frequency, severity and duration of outbreaks of equine influenza in North America.  相似文献   

What is your diagnosis? Hip joint luxation with secondary osteoarthritis and pseudoarthrosis     

Witsberger TH  Cook JL  Cook CR 《Journal of the American Veterinary Medical Association》2007,230(11):1631-1632

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Investigations on resistance of oats to Heterodera avenae: Location of resistance genes     

B. H. Chew  R. Cook  H. Thomas 《Euphytica》1981,30(3):669-673

Summary By using 15 available mono/nullisomic lines of Sun II back ground, the Heterodera avenae resistance gene in Nelson (from Avena sativa CI 3444) and Panema (from A. sterilis I. 376) were located on monosome XV. Genes with smaller effects were located on monosomes VIII and X. The absence of these genes derived from Sun II would increase cyst production on plants lacking major resistance genes.  相似文献   

Impacts of the ancient Maya on soils and soil erosion in the central Maya Lowlands     

T. Beach  N. Dunning  S. Luzzadder-Beach  D.E. Cook  J. Lohse 《CATENA》2006

Many studies across the central and southern Maya Lowlands of Belize, Guatemala, Honduras, and Mexico have produced records of land degradation, mostly sedimentation and soil erosion, during the ancient Maya period from before 1000 BC to the Maya Collapse of c. AD 900. This paper provides new data from two sites (Blue Creek and Cancuén), synthesizes more than a decade of the authors' research in Guatemala, Belize, and Mexico, and synthesizes other findings from this region. These research projects analyzed more than 100 excavations in upland and depression sites, cored lakes and wetland sediments, and studied sediments in the field and laboratory using radiocarbon dating, a battery of soil chemistry tests, stratigraphic analysis, magnetic susceptibility, elemental analyses, and artifact identification. Our objective was to date when sedimentation and soil erosion occurred, identify stable surfaces, and correlate them with the state of knowledge about past land use. These findings indicate three general epochs of accelerated soil erosion and identified two major paleosols. The three waves of soil erosion occurred in the Preclassic period (c. 1000 BC to AD 250), the Late Classic (AD 550 to 900), and in the last several decades. The major paleosol (‘Eklu'um’) in these sites is a well-developed Mollisol or Vertisol that started forming in the early Holocene and was buried in either the Preclassic or Classic periods (AD 250 to 900). At some sites the Eklu'um paleosol lies beneath sediments with a fainter paleosol, which in turn lies buried below Classic period and later sediments. This picture shows higher than expected soil erosion linked to the region's first pioneer farmers in the Preclassic and less than expected soil erosion in the Late Classic when population peaked and land use was the most intensive. In other regions like Cancuén, Guatemala, however, most soil erosion occurred during the Maya Late Classic (AD 550–830). Erosion here was intense but short-lived: depressions record 1–3 m of aggradation in two centuries. A third epoch of accelerated soil loss and aggradation arose with the rapid land use changes brought by new pioneers during the last several decades.  相似文献   

Climate change and forest decline: A review of the red spruce case     

Edward R. Cook  Arthur H. Johnson 《Water, air, and soil pollution》1989,48(1-2):127-140

Climate change as a contributor to the decline of red spruce is investigated. Previous climatic response model results are reviewed and more detailed time-dependent modeling of tree growth-climate interactions are performed using the Kalman filter. These new results show that there is a clear temporal and elevational dependence in the response of red spruce to climate. Influence of abnormally warm prior-August temperatures become increasingly time-dependent with decreasing elevation, which is contrary to the elevational gradient in the severity of decline. Thus, this variable, which had been implicated in red spruce declines from previous studies, is unlikely to be a primary cause of the current decline. However, it may be implicated in earlier declines at low elevations. Prior-December temperatures are influential at all elevations, but time-dependent only at the highest elevational zone. The emergence of a strongly time-dependent prior-November temperature response is clearly associated with a time-trend in the temperature record. Thus, it is likely that red spruce is responding, in a transient sense, to changing climate. An additional transient response to current-July temperatures is not associated with any unusual behavior in the data and is, as yet, unexplained. These results show that red spruce is not in equilibrium with its climatic environment, which may have made it more susceptible to damage caused by natural and anthropogenic factors.  相似文献   

Utilization of volatile fatty acids in ruminants. IV. Relative activities of acetyl CoA synthetase and acetyl CoA hydrolase in mitochondria and intracellular localization of acetyl CoA synthetase   总被引：5，自引：0，他引：5  

S Quraishi  R M Cook 《Journal of agricultural and food chemistry》1972,20(1):91-95

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Metabolism of xenobiotics in ruminants. Use of activated carbon as an antidote for pesticide poisoning in ruminants     

K A Wilson  R M Cook 《Journal of agricultural and food chemistry》1970,18(3):437-440

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Metabolism of xenobiotics in ruminants. IV. Storage and excretion of HEOD in Holstein cows     

K A Wilson  R M Cook 《Journal of agricultural and food chemistry》1972,20(2):391-394

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Relationship between soil respiration and soil moisture     

Valerie A. Orchard  F.J. Cook 《Soil biology & biochemistry》1983,15(4):447-453

Microbial activity is affected by changes in the availability of soil moisture. We examined the relationship between microbial activity and water potential in a silt loam soil during four successive drying and rewetting cycles. Microbial activity was inferred from the rate of CO₂ accumulating in a sealed flask containing the soil sample and the CO₂ respired was measured using gas chromatography. Thermocouple hygrometry was used to monitor the water potential by burying a thermocouple in the soil sample in the flask. Initial treatment by drying on pressure plates brought samples of the test soil to six different water potentials in the range -0.005 to -1.5MPa. Water potential and soil respiration were simultaneously measured while these six soil samples slowly dried by evaporation and were remoistened four times. The results were consistent with a log-linear relationship between water potential and microbial activity as long as activity was not limited by substrate availability. This relationship appeared to hold for the range of water potentials from ?0.01 to ?8.5 MPa. Even at ?0.01 MPa (wet soil) a decrease in water potential from ?0.01 to ?0.02 MPa caused a 10% decrease in microbial activity. Rewetting the soil caused a large and rapid increase in the respiration rate. There was up to a 40-fold increase in microbial activity for a short period when the change in water potential following rewetting was greater than 5 MPa. Differences in microbial activity between the wetter and drier soil treatments following rewetting to the original water potentials are discussed in terms of the availability of energy substrate.  相似文献