In vitro and in vivo immune responses in neonatally thymectomized holstein-friesian calves exposed to bovine viral diarrhea virus

Neonatally thymectomized and normal Holstein-Friesian calves were exposed to bovine viral diarrhea virus and challenged 22 days later. Baseline values in non-specific mitogen induced lymphocyte blastogenesis and serologic responses to tetanus toxoid and Brucella abortus strain 19 were established in neonatally thymectomized and normal calves.Neither viral recovery nor protective antibody production followed the very low level primary exposure to bovine viral diarrhea virus. The expected clinical response to an appropriate challenge inoculum did not occur, however, suggesting an immune response to bovine viral diarrhea virus had been initiated by the primary exposure. Five of eight calves developed protective serum levels of bovine viral diarrhea antibody. This may represent an example of immunologic priming. Exposure to low levels of bovine viral diarrhea virus also has potential implications in the pathogenesis of chronic bovine viral diarrhea wherein low level exposure may interfere with the development of protective levels of bovine viral diarrhea antibody as was observed in three calves.Circulating lymphocyte concentrations and results of non-specific mitogen stimulation of lymphocytes revealed a reduced phytohemagglutinin response in conjunction with a slightly increased response to bacterial lipopolysaccharide and pokeweed mitogen in the presence of moderate lymphopenia. The capacity of lymphocytes to respond to phytohemagglutinin was unchanged but an increased total response, as occurred in control thymectomized and intact calves, did not occur.The response to tetanus toxoid, a thymus-independent antigen, was increased following exposure to bovine viral diarrhea virus, perhaps reflecting an alteration in thymic-independent regulation. The lack of a differential response to Brucella abortus strain 19 implied competence in thymus-dependent helper cells.     

The effect of vitamin E supplementation on discoloration of injection-site lesions in retail cuts and the greening reaction observed in injection-site lesions in muscles of the chuck

Concern has been raised about green discoloration of injection-site lesions in chuck muscles in modified-atmosphere packages. Objectives were: 1) to recreate green lesions, 2) to compare the severity of discoloration of injection-site lesions in chucks from carcasses of control or vitamin E-supplemented steers, and 3) to identify pigment(s) responsible for discoloration via in vitro color reactions. In Exp. 1, 23 steers (BW = 415 kg; 37 d before harvest) were injected with one of 12 pharmaceuticals, following label directions for route and dose, with the exception of a 5-mL maximum dose, to identify a product that could result in discoloration. Two vaccines (Products A and B) resulted in greening. In Exp. 2, 50 steers were injected (i.m.) with Product A and assigned to the control or vitamin E (1,000 IU/steer daily for 60 d) group. After retail display, 80 and 72% of steaks from the control and treatment groups, respectively, were discolored. Although vitamin E did not reduce (P = 0.53) greening, there was a trend (P = 0.10) toward delay discoloration of lesions from the treatment group. In Phase I of Exp. 3, pigments extracted from green lesions obtained from Exp. 2 were compared with solutions, exposed to a high partial pressure of oxygen (ppO), of myoglobin (Mb), copper sulfate, hydrogen peroxide (H2O2), vaccine, and aluminum hydroxide either alone or in combination. In Phase II of Exp. 3, solutions of two or more of Mb, Cu, sodium sulfide, sodium sulfite, sodium sulfate (Na2SO4), and H2O2 were made at pH 7.2 or 5.5 and exposed to low or high ppO. Normal muscle tissue displayed a 3.2 and 56.7% decrease in absorbance/microg of protein as wavelength changed from 654 to 656 nm and 656 to 658 nm, respectively. Pigments from control and treatment group green tissue displayed a 164.5 and 621.3% increase, respectively, in absorbance/microg of protein as wavelength changed from 654 to 656 nm. As wavelength changed from 656 to 658 nm, the absorbance/microg of protein for control and treatment group lesions decreased by 75 and 109%, respectively. The Mb+Cu+Na2SO4 solution, at pH 5.5 and high ppO, exhibited similar absorbance trends as green lesions indicating that greening may result from a Mb, Cu, and Na2SO4 interaction. Results indicated that greening varies with pharmaceuticals and oxidation of tissue cannot be controlled with vitamin E supplementation. Research on the causative agents of green discoloration, with an emphasis on compounds containing sulfate or Cu, is needed.     

The influence of dietary protein and energy levels on growth and survival of penaeid shrimp

Two feeding experiments were conducted on the effects of levels of dietary protein, carbohydrates and lipids on growth and survival of penaeid shrimp. In the first experiment, a series of 14 semi-purified formulations which contained 28 to 52% protein, 0 to 40% glucose, and 0 to 20% supplemental lipid were fed for a ten-week period. In the second experiment, 12 diets which contained 14 to 32% protein, 0 to 30% starch, and 0 to 10% supplemental lipid were fed for eight weeks. Results from these studies indicated that 28–32% was the optimal protein level and that the addition of starch to the diet enhanced growth whereas supplemental glucose caused a reduction in weight gains. Groups fed diets containing a lipid supplement had poor growth and survival rates.     

Assessment of test results when using a commercial enzyme-linked immunosorbent assay for diagnosis of paratuberculosis in repeated samples collected from adult dairy cattle

OBJECTIVE: To determine the proportion of adult cattle that change test status when an ELISA for antibodies against Mycobacterium avium subsp paratuberculosis (MAP) is used to assay samples collected twice at variable intervals and to determine whether cows with an initial strong positive result were more likely to maintain positive status, compared with all cows with an initial positive result. DESIGN: Cross-sectional observational study. ANIMALS: 3,757 adult dairy cattle. PROCEDURE: Serum samples were obtained twice from cattle at intervals ranging from 77 to 600 days between collections. Samples were tested with an ELISA for detection of antibodies to MAP. RESULTS: Of 157 cattle with initial positive results (value for the sample divided by the value for positive-control serum [S/P] > or = 0.25), 62 (39.5%) had negative results for the second sample. Of 71 cattle with an initial S/P value > or = 0.40, 13 (18.3%) had a negative result (S/P < 0.25) for the second sample. Of 33 cattle with an initial S/P > or = 0.70, 3 (9.1%) had a negative result (S/P value < 0.25) for the second sample. Interval between collection of samples did not affect results. CONCLUSIONS AND CLINICAL RELEVANCE: Many cows changed ELISA status between samples collected at variable intervals. Cows with an initial high S/P value (> or = 0.70) were more likely to maintain positive status than cows classified as positive on the basis of cutoff values of > or = 0.25 or > or = 0.40. Veterinarians should expect variability in ELISA results when repeated testing of cattle is used as part of an MAP control program.     

Diagnosis of taenia saginata cysticercosis by immunohistochemical test on formalin-fixed and paraffin-embedded bovine lesions.

A new method of diagnosing cysticercus or larval stage of the human tapeworm, Taenia saginata, also known as Cysticercus bovis, in formalin-fixed bovine tissue was developed using a monoclonal antibody to T. saginata and avidin-biotin complex immunohistochemistry. Grossly recognizable viable and degenerate cysts were identifiable after immunohistochemical staining and could be differentiated from Sarcocystis, Actinobacillus, or non-cyst, normal bovine structures. Thenew test should permit laboratory confirmation of suspected T. saginata cysticercus lesions.     

Spinach curly top virus: A Newly Described Curtovirus Species from Southwest Texas with Incongruent Gene Phylogenies

ABSTRACT A curtovirus associated with a disease of spinach was isolated in southwest Texas during 1996. Disease symptoms included severe stunting and chlorosis, with younger leaves curled, distorted, and dwarfed. Viral DNA was purified and an infectious clone obtained. Agroinoculation using a construct bearing full-length tandem repeats of the cloned viral genome resulted in systemic infection of species in six of seven plant families tested, indicating that the virus has a wide host range. Symptoms produced in spinach agroinoculated with cloned viral DNA were similar to those observed in the field. Viral single-stranded and double-stranded DNA forms typical of curtovirus infection were detected in host plants by Southern blot hybridization. The complete sequence of the infectious clone comprised 2,925 nucleotides, with seven open reading frames encoding proteins homologous to those of other curtoviruses. Complete genome comparisons revealed that the spinach curtovirus shared 64.2 to 83.9% nucleotide sequence identity relative to four previously characterized curtovirus species: Beet curly top virus, Beet severe curly top virus, Beet mild curly top virus, and Horseradish curly top virus. Phylogenetic analysis of individual open reading frames indicated that the evolutionary history of the three virion-sense genes was different from that of the four complementary-sense genes, suggesting that recombination among curtoviruses may have occurred. Collectively, these results indicate that the spinach curtovirus characterized here represents a newly described species of the genus Curtovirus, for which we propose the name Spinach curly top virus.     

Integrating supply and demand in ecosystem service bundles characterization across Mediterranean transformed landscapes

Context

Humans continually transform landscapes, affecting the ecosystem services (ES) they provide. Thus, the spatial relationships among services vary across landscapes. Managers and decision makers have access to a variety of tools for mapping landscapes and analyzing their capacity to provide multiple ES.

Objectives

This paper characterizes and maps ES bundles across transformed landscapes in southeast Spain incorporating both the ecological and social perspectives. Our specific goals were to: (1) quantify ES biophysical supply, (2) identify public awareness, (3) map ES bundles, and (4) characterize types of ES bundles based on their social-ecological dimensions.

Methods

Biophysical models and face-to-face social surveys were used to quantify and map ES bundles and explore the public awareness in a highly transformed Mediterranean region. Then, we classified ES bundles into four types using a matrix crossing the degree of biophysical ES supply and the degree of social awareness.

Results

Results mapped seven ES bundles types representing diverse social-ecological dynamics. ES bundles mapped at the municipality level showed mismatches between their biophysical provision and the public awareness, which has important implications for operationalizing the bundles concept for landscape planning and management. ES bundles characterization identified four types of bundles scenarios.

Conclusions

We propose an ES bundles classification that incorporates both their social and ecological dimensions. Our findings can be used by land managers to identify areas in which ES are declining as well as priority areas for maximizing ES provision and can help to identify conflicts associated with new management and planning practices.