Pulmonary lesions induced by 3-methylindole and bovine respiratory syncytial virus in calves     

W L Castleman  S Lacy  D O Slauson  J Atz 《American journal of veterinary research》1990,51(11):1806-1814

Our objectives were to describe the ultrastructural morphogenesis of pulmonary lesions induced by 3-methylindole in 30- to 45-day-old Holstein calves and to determine whether toxic exposure to 3-methylindole exacerbates pulmonary lesions induced by bovine respiratory syncytial virus. Administration of 3-methylindole (0.25 g/kg) to calves resulted in interstitial edema and ultrastructural swelling of type-I alveolar epithelial cells and nonciliated bronchiolar epithelial cells as early as 4 to 6 hours after intraruminal administration. More severe alveolar edema containing protein was associated with swelling of capillary endothelial cells at 2 days after administration. Proliferation of type-II alveolar epithelial cells was first observed at 2 days after 3-methylindole administration, and marked hyperplasia of type-II epithelial cells and nonciliated bronchiolar epithelial cells was evident by 4 days after administration. Pulmonary cytochrome P-450 monooxygenase concentrations decreased significantly (P less than 0.001) by 12 hours after administration and did not increase significantly again by 8 days after administration. Calves were inoculated with bovine respiratory syncytial virus 3 days after administration of 3-methylindole, and pulmonary lesions were assessed 5 days after viral inoculation. Viral replication was demonstrated by fluorescence microscopy for viral antigen or by transmission electron microscopy in ciliated and nonciliated airway epithelial cells. Viral antigen was identified infrequently in alveolar macrophages and in type-II alveolar epithelial cells. 3-Methylindole exposure in calves did not result in more widespread distribution of viral antigen in alveolar tissue of respiratory syncytial virus-inoculated calves or in significant enhancement of viral pneumonia.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Research,extension, and user partnerships: Models for collaboration and strategies for change     

William B. Lacy 《Agriculture and Human Values》1996,13(2):33-41

Increasing pragmatic and ethical concerns have been raised about the inadequacies of conventional approaches to agricultural research and extension worldwide and the lack of integrated efforts among researchers, extension educators, and users. This paper examines three models of these relationships: the diffusion or supply model; the induced innovation or demand model; and the synthesis triangular or supply/demand model. The triangular model builds and improves upon the previous models by focusing on the role of clients or users in the broadest sense in creating a demand for science and extension education, as well as on the role of scientists and extension educators in creating a supply. The triangular model views the relationship as an interactive partnership in which research and extension education are conducted in response to client needs and demands expressed through negotiation, persuasion, and coercion involving all partners. To implement this model will require significant organizational and managerial changes as well as reorientation in the values and attitudes of researchers, extension educators, clients, and their organizations. The remainder of the paper presents a brief discussion of suggested strategies at the individual, institutional, regional, national, and international levels for enhancing this partnership in order to more effectively meet the future needs of our food system.  相似文献   

Agriculture policy: Issues for the '80s and beyond     

Lawrence Busch  William B. Lacy 《Agriculture and Human Values》1984,1(1):5-9

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Root surface-inhabiting bacteria and the expression of clubroot of radish in controlled environments     

T.K. Kroll  G.H. Lacy  L.D. Moore 《Soil biology & biochemistry》1984,16(3):265-267

The effect of bacteria on the expression of clubroot of radish caused by the obligate parasite, Plasmodiophora brassicae, was studied. Inoculations with the bacterial strains isolated from roots of radish plants increased slightly, decreased slightly or did not change the number of root hairs colonized by P. brassicae in the root hair, i.e. primary phase of colonization. Five of six bacterial strains decreased the incidence of clubroot which was associated with a decrease in the extent of P. brassicae -colonization of the stele, i.e. secondary phase colonization. The role of root surface-inhabiting bacteria in clubroot disease development in radish under controlled environmental conditions is discussed.  相似文献   

Small mammals, habitat patches and PVA models: a field test of model predictive ability     

D.B Lindenmayer  R.C Lacy 《Biological conservation》2002,103(3):247-265

The results are described of comparisons between actual values for patch occupancy for two species of Australian small mammals (Bush Rat Rattus fuscipes and Agile Antechinus Antechinus agilis) determined from field sampling and predictions of patch occupancy made using VORTEX, a generic simulation model for Population Viability Analysis (PVA). The work focussed on a fragmented forest in south-eastern Australia comprised of a network of 39 patches of native eucalypt forest surrounded by extensive stands of exotic softwood Radiata Pine (Pinus radiata) plantation. A range of modelling scenarios were completed in which four broad factors were varied: (1) inter-patch variation in habitat quality; (2) the pattern of inter-patch dispersal; (3) the rate of inter-patch dispersal; and (4) the population sink effects of the Radiata Pine matrix that surrounded the eucalypt patches. Model predictions were made for the total number of animals, the distribution of animal density among patches, the total number of occupied patches, and the probability of patch occupancy. Predictions were then compared with observed values for these same measures based on extensive field surveys of small mammals in the patch system. For most models for the Bush Rat, the predicted relative density of animals per patch correlated well with the values estimated from field surveys. Predictions of patch occupancy were not significantly different from the actual value for the number of occupied patches in half the models tested. The better models explained 10-16% of the log-likelihood of the probability of patch occupancy. While some of the models gave reasonable forecasts of the number of occupied patches, even in these cases, they had only moderate ability to predict which patches were occupied. Field surveys revealed there was no relationship between patch area and population density for the Agile Antechinus—an outcome correctly predicted by only a few models. Five of the 18 scenarios completed for the Agile Antechinus gave predicted numbers of occupied patches not significantly different from the observed number. In each of these five cases, large standard deviations around the mean predicted value meant uncertainty generated by the simulation model limited the predictive power of the PVA. Some of the models gave reasonable predictions for the number of occupied patches, but those models were unable to predict which ones were actually occupied. The results of our study suggest that key processes influencing which specific patches would be occupied were not modelled appropriately. High levels of variability and fecundity drive the population dynamics of the Bush Rat and Agile Antechinus, making the patch system unpredictable and difficult to model accurately. Despite the fact that both the Bush Rat and the Agile Antechinus are two of the most studied mammals in Australia, there are attributes of their biology that are presently poorly understood (which were not included in the VORTEX model), but which could strongly influence patch occupancy. For example, local landscape features may be important determinants of inter-patch movement and habitat utilisation in the patch system. Further empirical studies are needed to explore this aspect of small mammal biology.  相似文献   

A greenhouse method for screening lettuce for resistance to Sclerotinia sclerotiorum     

Abdul Madjid  Shigemi Honma  Melvyn L. Lacy 《Scientia Horticulturae》1983,18(3):201-206

Agar blocks colonized by Sclerotinia sclerotiorum, causal agent of lettuce drop, were used as inoculum in screening for resistance to this pathogen in the greenhouse.Since the degree of resistance to the pathogen among cultivars varied with the time observed after inoculation, resistance was assessed by the number of days for 50% of the plants of each cultivar to die, as well as the number of plants that died. The cultivars ‘PI (Plant Introduction) 250427’, ‘Taiwan’, ‘PI 251790’, ‘PI 255568’, ‘MSU 73-44’ and ‘Bibb’ were found to have a higher level of resistance to S. sclerotiorum than the cultivar ‘Grand Rapids’ at 12 or 15 days following inoculation.  相似文献   

Immunohistochemical localization of renin-containing cells in two elasmobranch species     

E. R. Lacy  E. Reale  L. Luciano 《Fish physiology and biochemistry》2016,42(3):995-1004

Renin immunoreactivity was localized at the light and electron microscopic level in two elasmobranch fish species, the Atlantic stingray, Dasyatis sabina, and river ray, Potamotrygon humerosa. At the light microscopic level, the peroxidase–anti-peroxidase method showed a positive immunoreactivity in modified smooth muscle cells in kidney afferent arterioles as well as in arterioles of several organs: rectal gland, inter-renal gland, conus arteriosus, and gill. Electron microscopic renin-positive immunogold localization was confined to the contents of membrane bound granules in the modified smooth muscle cells of these arterioles. The presence of renin-containing granules in the modified smooth muscle, “granular cells,” of the renal glomerular afferent arteriole of these two stingray species adds support to earlier studies which showed the structural components of a complete juxtaglomerular apparatus and some of the biochemical and molecular components of a renin–angiotensin system (RAS) as found in teleost fish, reptiles, birds, and mammals. A notable result, however, was the renin-positive immunoreaction in the arteriolar wall of all other organs studied here. The presence of this “diffuse renin system” in the connective tissue of various organs suggests that in these two stingray species in addition to local organ-specific functions, the RAS may act as a systemic mechanism to regulate blood pressure and blood flow in the body.  相似文献   

Rapid phenotyping for adult‐plant resistance to stripe rust in wheat     

Lee T. Hickey  Peter M. Wilkinson  Cheridan R. Knight  Ian D. Godwin  Olena Y. Kravchuk  Elizabeth A. B. Aitken  Urmil K. Bansal  Harbans S. Bariana  Ian H. De Lacy  Mark J. Dieters 《Plant Breeding》2012,131(1):54-61

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Molecular cloning of an endo-pectate lyase gene from Erwinia carotovora subsp. atroseptica     

Caitilyn Allen  Helga George  Zhenbiao Yang  George H. Lacy  Mark S. Mount 《Physiological and Molecular Plant Pathology》1987,31(3)

We report the construction of a clone library of the Erwinia carotovora subsp. atroseptica genome and the isolation of a gene for endo-pectate lyase. The library, inserted into the PstI site of plasmid pBR322, contains approximately 1700 clones. Five of these produce pectolytic enzymes as detected by a plate screening assay. Using a cloned endo-pectate lyase gene from the related bacterium, E. carotovora subsp. carotovora, as a probe, we found that one pectolytic E. carotovora subsp. atroseptica clone had strong homology to the probe. We characterized that clone by restriction endonuclease mapping and studied its pectolytic protein product. The purified enzyme is an endo-pectate lyase with a cofactor preference for Co²⁺. The molecular weight of the protein is 31 000 and it has an isoelectric focusing point of 9·2, corresponding to an endo-pectate lyase produced by E. carotovora subsp. atroseptica, but not to the protein product of the E. carotovora subsp. carotovora probe DNA, which has a pI of 9·5. Restriction endonuclease site polymorphisms in the two cloned endo-pectate lyase genes suggest substantial sequence divergence between these two loci.  相似文献   

The Two Cultures of Science： Implications for University-Industry Relationships in the U.S. Agriculture Biotechnology     

William B Lacy  Leland L Glenna  Dina Biscotti  Rick Welsh  Kate Clancy 《农业科学学报》2014,13(2):455-466

Partnerships between U.S. universities and industries have existed for several decades and in recent years have become generally more varied, wider in scope, more aggressive and experimental and higher in public visibility. In addition, in the last few decades, public and private interests have advocated for government policies and laws to globally promote the commercialization of university science. This paper examines the persistence or convergence of the two cultures of science and the implications of this commercialization for university-industry relationships in agriculture biotechnology. The perceptions and values of over 200 U.S. university and industry scientists, managers and administrators who participate in or oversee research collaborations in agricultural biotechnology were analyzed. The findings revealed that the participants in these research relationships continue to perceive very distinct cultures of science and identify a wide range of concerns and disadvantages of these partnerships. Several actions were discussed to ensure that the two cultures serve complementary roles and that they maximize the public benefits from these increasing collaborations.  相似文献