Effect of staphylococcal enterotoxin B on cardiorenal functions in rhesus macaques.     

C T Liu  R D DeLauter  M J Griffin  R T Faulkner 《American journal of veterinary research》1978,39(2):279-286

Selected cardiovascular and renal functions were measured for 5 hours in conscious, chair-restrained, female rhesus macaques (Macaca mulatta) after IV (0.05 and 1.0 mg/kg) or oral (1.0 mg/kg) administration of staphylococcal enterotoxin B (SEB). Cardiovascular functions, renal hemodynamics, and renal metabolism were also studied between 6 and 11 hours after IV SEB inoculation. Oral SEB produced few changes in cardiorenal functions. In contrast, IV SEB produced hypotension, tachycardia, increased total peripheral and renal vascular resistance, and decreased cardiac and renal functions. The early significant (P less than 0.05) renal depression was not associated with hypotension (mean arterial blood pressure greater than 100 mm of Hg). However, all measured renal functions except extraction ratio of PAH were positively correlated with decreased blood pressure (r = 0.52 - 0.71) in the later phase of SEB toxemia. It is concluded that the kidney is one of the organs affected by IV SEB. Renal impairment may partially contribute to death during SEB enterotoxemia in macaques.  相似文献   

Kin discrimination and the benefit of helping in cooperatively breeding vertebrates     

Griffin AS  West SA 《Science (New York, N.Y.)》2003,302(5645):634-636

In many cooperatively breeding vertebrates, a dominant breeding pair is assisted in offspring care by nonbreeding helpers. A leading explanation for this altruistic behavior is Hamilton's idea that helpers gain indirect fitness benefits by rearing relatives (kin selection). Many studies have shown that helpers typically provide care for relatives, but relatively few have shown that helpers provide closer kin with preferential care (kin discrimination), fueling the suggestion that kin selection only poorly accounts for the evolution of cooperative breeding in vertebrates. We used meta-analysis to show that (i) individuals consistently discriminate between kin, and (ii) stronger discrimination occurs in species where the benefits of helping are greater. These results suggest a general role for kin selection and that the relative importance of kin selection varies across species, as predicted by Hamilton's rule.  相似文献   

Isolation and differentiation of bovine mammary gland progenitor cell populations   总被引：3，自引：0，他引：3  

Holland MS  Tai MH  Trosko JE  Griffin LD  Stasko JA  Cheville NC  Holland RE 《American journal of veterinary research》2003,64(4):396-403

OBJECTIVE: To isolate bovine mammary gland cells with stem cell characteristics. SAMPLE POPULATION: Monolayers of bovine mammary gland cells. PROCEDURE: Mammary gland cell populations were separated by use of selected media supplements. Phenotypic characteristics were examined via light and transmission electron microscopy. Cellular expression of casein and connexin 43 was identified immunohistochemically. A scrape-loading and dye transfer assay was used to examine the mammary gland cell populations for homogenous gap junctional intercellular communication (GJIC). RESULTS: Subpopulations of mammary gland cells grown in vitro are classified on the basis of their distinct morphologic features and ability to communicate via gap junctions. Ultrastructurally, 2 morphologically distinct cell types were classified as type I and II cells. Type I cells were small light undiffertiated cells and large light undifferentiated cells that were deficient in functional gap junctions (as is characteristic of stem cells). Type II cells included large light differentiated cells and terminally differentiated cells; GJIC was functional in type II cells. Type II cells had cytoplasmic expression of connexin 43, whereas, type I cells did not. All cells expressed casein. CONCLUSIONS AND CLINICAL RELEVANCE: Subpopulations of bovine mammary gland cells with stem cell characteristics were identified. Phenotypic differences are observed among type I bovine mammary gland cells with stem cell characteristics. Gap junctional intercellular communication may be necessary for the differentiation of stem cells. Characterization of bovine mammary gland stem cells and their progeny may provide a new tool with which to study mammary gland health.  相似文献   

Transmission of Mycobacterium bovis from experimentally infected ferrets to non-infected ferrets (Mustela furo)     

Qureshi T  Labes RE  Lambeth M  Montgomery H  Griffin JF  Mackintosh CG 《New Zealand veterinary journal》2000,48(4):99-104

AIMS: To demonstrate the transmission of Mycobacterium bovis infection from experimentally infected ferrets (Mustela furo) to non-infected ferrets in a laboratory setting, using three different isotypes of M. bovis, and to observe ferret behaviour that might be implicated in disease transmission. METHODS: Three female ferrets, each experimentally infected with a unique strain of M. bovis, were housed together with six female and two male non-infected ferrets in an isolation facility. Transmission of infection was monitored clinically, serologically (using an ELISA test), bacteriologically, histologically, and by isotype analysis of M. bovis isolates using spoligotyping to determine whether or not transmission of each strain occurred. Ferret behaviour was observed using a time-lapse video recorder. RESULTS: Transmission of M. bovis infection was confirmed in two male and four female ferrets. Isotype analysis showed that of the experimentally infected females, one did not infect any other ferret, another transmitted M. bovis to one ferret before it died prematurely 49 days post-infection, and the third, which was cannibalised, appears to have transmitted M. bovis to both males and three females. However, two of these latter three females had died before the event of cannibalism took place. One female was infected with two strains. Several behavioural interactions were observed that could have resulted in M. bovis transmission, including den sharing, sniffing of orifices and faeces, cannibalism and aggressive breeding behaviour. CONCLUSIONS: Horizontal transmission of M. bovis infection was demonstrated in ferrets under experimental housing conditions. Routes of transmission may involve cannibalism and factors such as den sharing, playing, fighting, mating, and sniffing of faeces.  相似文献   

Assessing performance of feedlot operations using epidemiology.     

Marilyn J Corbin  Dee Griffin 《Veterinary Clinics of North America: Food Animal Practice》2006,22(1):35-51

The progressive feedlot veterinarian must be well versed not only in individual production animal medicine, but also in population-based medicine. Feedlot health programs must be goal oriented, and evaluation of these goals is accomplished through diligent use of record systems and analytic evaluation of these record systems. Basic feedlot monitoring parameters include health and economic parameters in addition to the use of bench marking parameters between and among feed yards. When these parameters have significant changes, steps should be initiated to begin field investigations. Feedlot epidemiology uses several novel applications such as partial budgeting, risk assessment, and packing plant audits to provide scientifically sound and economically feasible solutions for the feeding industry.  相似文献   

世界乳品工业展望     

Michael Griffin  张萍 《乳业科学与技术》2000,23(4):5-9

1、前言 联合国粮农组织的商品与贸易处最近完成了对2005年包括牛乳及乳制品在内的各类农产品的预测。这次预测不仅考虑了乌拉圭回合中有关贸易自由化的内容,还考虑了与乌拉圭回合无关的一些  相似文献   

Leaf respiration at different canopy positions in sweetgum (Liquidambar styraciflua) grown in ambient and elevated concentrations of carbon dioxide in the field     

Tissue DT  Lewis JD  Wullschleger SD  Amthor JS  Griffin KL  Anderson OR 《Tree physiology》2002,22(15-16):1157-1166

Trees exposed to elevated CO2 partial pressure ([CO2]) generally show increased rates of photosynthesis and growth, but effects on leaf respiration are more variable. The causes of this variable response are unresolved. We grew 12-year-old sweetgum trees (Liquidambar styraciflua L.) in a Free-Air CO2 Enrichment (FACE) facility in ambient [CO2] (37/44 Pa daytime/nighttime) and elevated [CO2] (57/65 Pa daytime/nighttime) in native soil at Oak Ridge National Environmental Research Park. Nighttime respiration (R(N)) was measured on leaves in the upper and lower canopy in the second (1999) and third (2000) growing seasons of CO2 fumigation. Leaf respiration in the light (R(L)) was estimated by the technique of Brooks and Farquhar (1985) in the upper canopy during the third growing season. There were no significant short-term effects of elevated [CO2] on R(N) or long-term effects on R(N) or R(L), when expressed on an area, mass or nitrogen (N) basis. Upper-canopy leaves had 54% higher R(N) (area basis) than lower-canopy leaves, but this relationship was unaffected by CO2 growth treatment. In August 2000, R(L) was about 40% of R(N) in the upper canopy. Elevated [CO(2)] significantly increased the number of leaf mitochondria (62%), leaf mass per unit area (LMA; 9%), and leaf starch (31%) compared with leaves in ambient [CO(2)]. Upper-canopy leaves had a significantly higher number of mitochondria (73%), N (53%), LMA (38%), sugar (117%) and starch (23%) than lower-canopy leaves. Growth in elevated [CO2] did not affect the relationships (i.e., intercept and slope) between R(N) and the measured leaf characteristics. Although no factor explained more than 45% of the variation in R(N), leaf N and LMA were the best predictors for R(N). Therefore, the response of RN to CO2 treatment and canopy position was largely dependent on the magnitude of the effect of elevated [CO2] or canopy position on these characteristics. Because elevated [CO2] had little or no effect on N or LMA, there was no effect on R(N). Canopy position had large effects on these leaf characteristics, however, such that upper-canopy leaves exhibited higher R(N) than lower-canopy leaves. We conclude that elevated [CO2] does not directly impact leaf respiration in sweetgum and that barring changes in leaf nitrogen or leaf chemical composition, long-term effects of elevated [CO2] on respiration in this species will be minimal.  相似文献   

Variations in dark respiration and mitochondrial numbers within needles of Pinus radiata grown in ambient or elevated CO2 partial pressure     

Griffin KL  Anderson OR  Tissue DT  Turnbull MH  Whitehead D 《Tree physiology》2004,24(3):347-353

Within-leaf variations in cell size, mitochondrial numbers and dark respiration rates were compared in the most recently expanded tip, the mid-section and base of needles of Pinus radiata D. Don trees grown for 4 years in open-top chambers at ambient (36 Pa) or elevated (65 Pa) carbon dioxide partial pressure (p(CO2)a). Mitochondrial numbers and respiratory activity varied along the length of the needle, with the highest number of mitochondria per unit cytoplasm and the highest rate of respiration per unit leaf area at the base of the needle. Regardless of the location of the cells (tip, middle or basal sections), needles collected from trees grown in elevated p(CO2)a had nearly twice the number of mitochondria per unit cytoplasm as those grown in ambient p(CO2)a. This stimulation of mitochondrial density by growth at elevated p(CO2)a was greater at the tip of the needle (2.7 times more mitochondria than in needles grown in ambient CO2) than at the base of the needle (1.7 times). The mean size of individual mitochondria was unaffected either by growth at elevated p(CO2)a or by position along the needle. Tree growth at elevated p(CO2)a had a variable effect on respiration per unit leaf area, significantly increasing respiration in the tip of the needles (+25%) and decreasing respiration at the mid-section and base of the needles (-14% and -25%, respectively). Although a simple relationship between respiration per unit leaf area and mitochondrial number per unit cytoplasm was found within each CO2 treatment, the variable effect of growth at elevated p(CO2)a on respiration along the length of the needles indicates that a more complex relationship must determine the association between structure and function in these needles.  相似文献   

Stomatal and non-stomatal limitations to photosynthesis in four tree species in a temperate rainforest dominated by Dacrydium cupressinum in New Zealand     

Tissue DT  Griffin KL  Turnbull MH  Whitehead D 《Tree physiology》2005,25(4):447-456

We assessed the relative limitations to photosynthesis imposed by stomatal and non-stomatal processes in Dacrydium cupressinum Lamb. (Podocarpaceae), which is the dominant species in a native, mixed conifer-broad-leaved rainforest in New Zealand. For comparison, we included three co-occurring broad-leaved tree species (Meterosideros umbellata Cav. (Myrtaceae), Weinmannia racemosa L.f. (Cunoniaceae) and Quintinia acutifolia Kirk (Escalloniaceae)) that differ in phylogeny and in leaf morphology from D. cupressinum. We found that low foliage phosphorus content on an area basis (P(a)) limited light-saturated photosynthesis on an area basis (A(sat)) in Q. acutifolia. Depth in the canopy did not generally affect A(sat) or the relative limitations to A(sat) because of stomatal and non-stomatal constraints, despite reductions in the ratio of foliage mass to area, foliar nitrogen on an area basis (N(a)) and P(a) with depth in the canopy. In the canopy-dominant conifer D. cupressinum, A(sat) was low, consistent with low values of the maximum rate of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) carboxylation (V(cmax)). In comparison, the A(sat) response of the three broad-leaved tree species was quite variable. Although A(sat) was high in the canopy-dominant M. umbellata, it was low in the sub-canopy trees W. racemosa and Q. acutifolia. Relative stomatal limitation to photosynthesis was more pronounced in W. racemosa (40%) than in the other three species (28-33%). Despite differences in degree, non-stomatal limitation to A(sat) predominated in all tree species.  相似文献   

Blight of conifer seedlings caused by Colletotrichum gloeosporioides     

Mark S. Griffin  Jack R. Sutherland  J. J. Dennis 《New Forests》1987,1(2):81-88

In a growth chamber experiment, 70-day-old seedlings of 10 conifer species were inoculated with Colletotrichum gloeosporioides conidia to determine the host range of the fungus. Based on the percentage of seedlings affected and the disease severity on individual seedlings, the order of most to least susceptibility was: western hemlock (WH), mountain hemlock, western larch, Sitka spruce, Engelmann spruce, Douglas-fir (coastal form, then interior form), white spruce and ponderosa pine; lodgepole pine and western red cedar remained unaffected. Inoculation of WH needles showed that within 24 h C. gloeosporioides conidia germinate and appressoria (penetration structures) form. A growth chamber study demonstrated that the pathogen can infect WH at needle wetness periods as short as 15 min; number of needles affected was higher at 0.5 h, but did not increase further even when wetness was extended up to 8 h. The results are discussed in relation to blight management of greenhouse-grown conifer seedlings.Portion of a Bachelor of Science (Honors) thesis, Department of Biology, University of Victoria, Victoria, British Columbia.  相似文献