Evaluation of Chinese Triticeae for resistance to Barley Yellow Dwarf Virus (BYDV)     

S. J. Xu  P. M. Banks  Y. S. Dong  R. H. Zhou  P. J. Larkin 《Genetic Resources and Crop Evolution》1994,41(1):35-41

Summary Barley Yellow Dwarf Virus (BYDV) is recognised as a major pathological constraint to cereal production in northern China and several widespread epidemics have been reported. The host range of BYDV includes not only cereals but many grasses. The indigenous Triticeae of northern China have likely been exposed to significant disease pressure from BYDV and therefore may be a potential source of BYDV resistance for cereal improvement. A wide range of Triticeae accessions collected over three expeditions in northern China were evaluated for resistance to BYDV. Seedlings were artificially inoculated and virus levels then assayed by ELISA. Resistance and immunity to BYDV were found to be widely distributed among the seven genera of Triticeae included in the screening. A high proportion of resistant and immune accessions was found in the genera Hordeum, Leymus, Elymus and Elytrigia. The wide range of reaction types to BYDV found within many species, and even between accessions of some species, indicates that natural selection for BYDV resistance may have been relatively recent in the Chinese Triticeae. A high proportion of resistance and/or immunity was found in Xinjiang compared to the general distribution. From the Chinese Triticeae tested the Leymus species may be the most appropriate material to initiate transfer of BYDV resistance to wheat.  相似文献   

Survival of the western pond turtle (Emys marmorata) in an urban California environment     

Phillip Q Spinks  Gregory B Pauly  H Bradley Shaffer 《Biological conservation》2003,113(2):257-267

The western pond turtle Emys (formerly Clemmys) marmorata is declining throughout its range, primarily due to loss of habitat via urbanization and conversion to agriculture. Urban waterways present several important challenges to freshwater turtle populations, but they also present an opportunity to maintain declining species in a ubiquitous habitat that has high public visibility. The arboretum waterway on the University of California, Davis campus is an example of an extensively altered urban habitat that supports a relatively large E. marmorata population. Over the last 6 years, we monitored the turtle population inhabiting the arboretum waterway to determine the demographic health of the population, and the challenges and opportunities that urban environments pose for pond turtles. Since 1993, the naturally existing arboretum pond turtle population has declined by approximately 40% and has shown little natural recruitment. During this time, we also introduced 31 headstarted turtles into the arboretum. Headstarting is the process of raising juveniles in captivity until they have outgrown their period of greatest vulnerability to predators, and then releasing them into the wild. Our headstarting results demonstrate that this contentious strategy is a viable option for adding young turtles to the population, although it does not address the causes of decline. Over the course of our study, we encountered nine species of non-native turtles in the waterway, and these appear to be a serious threat to the native species. As more habitat becomes urbanized, it is increasingly important to understand how freshwater turtles, such as E. marmorata, adapt to urban waterways and the impact of non-native turtles on native turtle species. Our strong feeling is that urban waterways can provide habitat for viable populations of freshwater turtles and showcase them to the public, but both the aquatic and terrestrial habitat must be managed according to the biological requirements of individual species.  相似文献   

Persistence of Atrazine and Alachlor in Ground Water Aquifers and Soil     

A. P. Schwab  P. A. Splichal  M. K. Banks 《Water, air, and soil pollution》2006,171(1-4):203-235

Degradation of atrazine and alachlor in saturated aquifer materials and soil was studied in the laboratory. A static aquifer was represented by a set of stagnant flasks and a well-mixed aquifer was simulated by recirculating columns. Water was tested at selected time intervals over six months and analyzed for herbicides and metabolites. Under all conditions, atrazine was more persistent than alachlor. Increased temperature had little effect on atrazine dissipation but did increase alachlor degradation rates, especially in the sterilized treatments. The addition of carbon and nitrogen prolonged the initial period before the onset of degradation in some of the columns. Enhanced mass transfer of the herbicides, nutrients, and oxygen in the recirculating columns dramatically increased dissipation of atrazine and alachlor. The degradation rates of atrazine and alachlor were 2 to 5 times faster in the recirculating columns than in the stagnant flasks. Atrazine was more persistent in the aquifer materials than in the soils, while alachlor dissipation was similar in the soils and recirculating aquifer columns, but was slower in the stagnant flasks. The prolonged persistence of atrazine under static, aquifer conditions (t _1/2 = 206 to 710 days) indicates that natural mechanisms are not sufficient to alleviate the risk of atrazine buildup over time; however, in a well mixed aquifer, atrazine degradation rates should be higher (t _1/2 = 66 to 106 days) and the threat of atrazine accumulation is diminished. Alachlor persistence at low concentrations (< 10 μg L^?1) in aquifers should not pose a long-term threat to ground water supplies.  相似文献   

Adsorption of Atrazine and Alachlor to Aquifer Material and Soil     

A. P. Schwab  P. A. Splichal  M. K. Banks 《Water, air, and soil pollution》2006,177(1-4):119-134

Atrazine [6-chloro-N-ethyl-N′-(1-methyl)-1,3,5 triazine-2,3-diamine] and alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide] are agricultural herbicides used in large quantities and, as a consequence, are common contaminants in groundwater and surface water. The retention of these herbicides in soils and their degradation in aqueous environments is highly dependent upon their adsorption to solid surfaces. The adsorption of atrazine and alachlor was investigated on three typical Kansas and underlying aquifers known to be vulnerable to contamination. More alachlor was adsorbed to the soils and sediments than atrazine. The adsorption coefficients for atrazine were 2 to 5 times higher for soils than for aquifer sediments. For alachlor, the adsorption coefficients were 4 to 20 times higher for soil than for aquifer solids. Both linear and Freundlich isotherms represented the adsorption data well in all cases. The slope of the Freundlich isotherms, 1/n, was close to one, with the exception of alachlor adsorption onto the Topeka aquifer sediment (1/n = 0.67). The K _d values found in these studies were comparable to the lower range of those reported in the literature.  相似文献   

COLOR DOPPLER AND DOPPLER SPECTRAL ANALYSIS IN THE SPINAL CORD OF NORMAL DOGS     

Judith A.  Hudson  DVM  PhD  Susan T.  Finn-Bodner  DVM  MS  Joan R.  Coates  DVM  Donald C.  Sorjonen  DVM  MS  Stephen T.  Simpson  DVM  MS  James C.  Wright  DVM  PhD  Jan E.  Steiss  DVM  PhD  Nancy R.  Cox  DVM  PhD  Dana M.  Vaughn  DVM  PhD  Starr C.  Miller  BS  Scott A.  Brown  DVM  PhD  Phillip D.  Garrett  DVM  MS 《Veterinary radiology & ultrasound》1995,36(6):542-547

Doppler ultrasonography of the spinal cord was performed in 34 normal, anesthetized dogs following hemilaminectomy. This study was part of an investigation to evaluate the efficacy of a 21-aminosteroid compound and high dose methylprednisolone for the treatment of spinal cord trauma. Grey-scale images of the canine spinal cord were similar to those described for the spinal cord of people. Doppler waveforms of intraparenchymal spinal arteries exhibited high end diastolic blood flow velocities, indicating low resistance to flow. Doppler values (mean ± SD) for arteries immediately ventrolateral to the central canal were: Peak Systolic Velocity = 5.78 ± 2.5 cm/sec, Minimum Diastolic Velocity = 3.5 ± 1.62 cm/sec, Mean Velocity = 4.45 ± 1.96 cm/sec, Minimum Diastolic Velocity = 3.5 ± 1.62 cm/sec, Mean Velocity = 4.45 ± 1.96 cm/sec, Systolic/Diastolic ratio = 169 ± 0.19, Pulsatility Index = 0.53 ± 0.09, and Resistance Index = 0.4 ± 0.06.  相似文献   

THE SCINTIGRAPHIC EVALUATION OF SOLID PHASE GASTRIC EMPTYING IN NORMAL CATS   总被引：1，自引：0，他引：1  

Phillip F.  Steyn  BVSc  MRCVS  MS  David  Twedt  DVM  Wanda  Toombs  CVT 《Veterinary radiology & ultrasound》1995,36(4):327-331

The gastric emptying half-time of solid food in normal cats was determined using a scintigraphic technique. ^99mTc-sulfur colloid was applied to dry food. Sequential images were acquired post prandial, and the gastric emptying half-time was determined for several different acquisition and processing parameters. Good correlation was found between different acquisition and processing methods, some of which made use of edge detection applications, while others used different views, or number of views from which the gastric emptying half-time was calculated. The mean ± standard deviation, (range) and median of the gastric emptying half-time determined using the geometric mean of total counts in hand-drawn regions of interest from the lateral and ventral images were 2.47 × 0.71, (1.42–3.61) and 2.37 hours respectably.  相似文献   

Augmented T lymphocyte responses and abnormal B lymphocyte numbers in goats chronically infected with the retrovirus causing caprine arthritis-encephalitis   总被引：1，自引：0，他引：1  

J C DeMartini  K L Banks  A Greenlee  D S Adams  T C McGuire 《American journal of veterinary research》1983,44(11):2064-2069

Caprine arthritis-encephalitis is a retrovirus-induced disease resulting in lymphoproliferative lesions of the CNS and joints. Peripheral blood leukocytes of chronically infected goats were analyzed for the types of cells present and for their reactivity to viral antigen and polyclonal stimulants. Two of 9 infected goats had abnormal numbers of B lymphocytes--one elevated and the other deficient. Lymphocyte reactivity to viral antigens was transiently detectable by a lymphoblastogenic assay in 5 of the 9 goats. The reactive cells were peanut agglutinin-negative T lymphocytes. Concanavalin A induced more division in T lymphocytes of infected goats than in lymphocytes of noninfected goats, whereas the reactions to phytohemagglutinin, pokeweed mitogen, and bacterial lipopolysaccharide were no different in the 2 goat groups. It is concluded that goats infected by the caprine arthritis-encephalitis virus have antigen-reactive T lymphocytes and that infection promotes the response to a nonspecific T-cell stimulant.  相似文献   

ULTRASONOGRAPHY OF THE EQUINE BICIPITAL TENDON REGION: A CASE HISTORY REPORT AND REVIEW OF ANATOMY     

Charles R.  Pugh  DVM  MS  Phillip J.  Johnson  BVSc  MS  Gregory  Crawley  DVM  MS  Susan T.  Finn  DVM  MS 《Veterinary radiology & ultrasound》1994,35(3):183-188

The equine shoulder region is difficult to investigate by conventional imaging modalities. Diagnostic ultrasound has proven valuable for investigation of soft tissue injuries of the human shoulder. In a horse with shoulder lameness, the authors employed diagnostic ultrasound to augment the use of conventional radiography. A defect in the subchondral bone layer of the medial humeral tuberosity, with adjacent bony fragments were clearly identified with ultrasound. Ultrasound was used for initial evaluation of the bicipital tendon and bursa. The technique was subsequently used to follow and evaluate the post-operative condition of the proximal cranial humerus, bicipital tendon and bursa in this patient. The bicipital regions of 2 immature and 3 adult normal horses were also examined with to illustrate the normal ultrasonographic anatomy of the cranial shoulder region.  相似文献   

A method for counting Fasciola eggs in cattle faeces in the field     

J W Parfitt  A W Banks 《The Veterinary record》1970,87(7):180-182

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SELECTED RADIOGRAPHIC CONDITIONS IN THE FELINE     

William C. Banks  D.V.M.  M.S. 《Veterinary radiology & ultrasound》1961,2(1):24-25

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