Studies on the purification of the leucocidin of Fusobacterium necrophorum and its neutralization by specific antisera

Leucocidin from several strains of Fusobacterium necrophorum was partially purified by gel filtration on Fractogel HW55 (F), the majority of the activity being present in the 50 ml of filtrate collected after 1.1 void volumes had passed through the column (termed Fraction 1, or #1). The material also contained lipopolysaccharide in 12.5% SDS-PAGE gels run under reducing conditions, but the protein did not migrate into 7.5% PAGE gels run under non-reducing conditions. Rabbit and bovine antisera to the leucocidin possessed antibodies against antigens in concentrated, washed culture supernates from toxigenic F. necrophorum and neutralized the leucocidal activity of such supernates. Absorption of the antisera with homologous, washed F. necrophorum cells reduced ELISA antibody titres by greater than 50%, but decreased neutralization titres by 15%. Absorbed rabbit IgG anti-#1 precipitated a single rocket in crossed immunoelectrophoresis and identified two proteins, of molecular weights (M.W.) 14 000 and 13 000, and 1 protein of M.W. 13 500 in immunoblots from toxigenic and non-toxigenic strains, respectively. An additional protein of M.E. 103 000 was present after SDS-PAGE separation of supernates from toxigenic but not non-toxigenic F. necrophorum and was not present in whole cell components. It was considered that the leucocidin may be present in a dimeric form in culture supernates from toxigenic strains. Antisera to leucocidins from several strains of F. necrophorum exhibited variable neutralization titres against leucocidins from heterologous bacteria.     

Classical swine fever: virulence and tissue distribution of a 1986 English isolate in pigs

Following the recurrence of classical swine fever in the United Kingdom in 1986, a virus isolated from a single outbreak was studied. A major factor in the spread of this disease is considered to be the presence of infectious virus in tissues taken from animals at certain stages of infection, although their condition may escape detection by routine inspection either before or after slaughter. Intranasal inoculation of the isolate into eight-week-old pigs reproduced the acute form of the disease. The pigs were killed or died between seven and 25 days after inoculation. The virus concentration was determined in a wide range of tissues taken at different stages of infection. Infectious virus was present at high concentrations in all the tissues taken and at all stages of infection. Any porcine tissue is therefore a potential source of infection even when it is taken either before the animal displays detectable signs of disease of after it develops serum neutralising antibodies.     

Retail cut yields of Rambouillet wether lambs fed the beta-adrenergic agonist L644,969.

Twenty Rambouillet wether lambs were given ad libitum access to a diet with (BAA, n = 10) or without (control, n = 10) 1 ppm of the beta-adrenergic agonist L644,969. Lambs were fed to a constant slaughter weight end point of 54.5 kg. Carcasses were fabricated to yield bone-in and boneless cuts that were trimmed progressively to 1.27, .64, .32, and .00 cm of s.c. fat remaining. Addition of BAA did not affect growth traits. Actual and adjusted fat thickness, body wall thickness, and percentage of kidney-pelvic fat did not differ between control and BAA lambs. However, BAA increased longissimus muscle area, longissimus muscle depth, and leg score while decreasing USDA yield grade. The BAA increased carcass conformation scores and decreased flank lean color scores. No other carcass quality measurements were affected by BAA. Addition of BAA did not affect overall carcass yields of bone-in retail cuts. However, BAA increased overall carcass yields of boneless retail cuts regardless of fat trim level. The BAA increased bone-in leg yield. Yield of boneless sirloin, bone-in loin and boneless loin were not affected by BAA. For these cuts, the percentage change from the control was highly dependent on fat trim level. There was no difference in short-cut, shank-off, semiboneless leg yield between control and BAA. Addition of BAA did not affect yield of bone-in rack regardless of fat trim level. However, BAA greatly increased yield of boneless ribeye. The BAA did not affect yield of bone-in or boneless shoulder.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thoracic, Abdominal and Vertebral Actinomycosis

The clinical, laboratory, radiographic, and histologic features and the response to therapy in three dogs with actinomycosis are reported. One dog (dog 1) had a 12-cm nonresectable mass extending from the ventrolateral chest wall into the left ventricular myocardium. Another dog (dog 2) had a diffuse peritonitis with "sulfur granules" and two large masses. One of these masses was nonresectable involving adjacent abdominal structures. A third dog (dog 3) had a subvertebral mass at T1-3 producing quadraplegia. Two dogs had periosteal reactions involving adjacent sternebrae (dog 1) or ribs and vertebral bodies (dog 3) that are characteristic of Actinomyces spp infections. In dogs 1 and 2 the diagnosis was based on the morphologic and tinctorial properties of free sulfur granules and/or tissue granules. Culture results were variable. Tissue from dog 1 yielded no growth, while polymicrobial infections, which included Actinomyces spp, were identified in dogs 2 and 3. Actinomyces odontolyticus was isolated from dog 3. Although the actinomycotic granulomas were either not excised or only partially excised from dogs 1 and 2, both animals were cured by the oral administration of high doses of penicillin G for 19 and 6 months, respectively. Dog 3 responded dramatically to the same antibiotic therapy given for 5 months. However, within 4 months of discontinuing treatment an abscess and draining fistulous tracts developed in the left axillary region. Two surgical fistulectomies and additional penicillin therapy were required to cure this animal. These cases and the current veterinary and human literature on actinomycosis are used to propose a rational approach to the treatment of actinomycosis in the dog.