响应面法优化姬松茸液体发酵培养基中红糖和酵母膏浓度

运用响应面分析法优化姬松茸液体发酵培养基中红糖和酵母膏浓度.结果表明,红糖浓度为20.24g/L、酵母膏浓度为2.055g/L时,菌丝体生物量最高,达2.279g/L;红糖浓度为20.8g/L、酵母膏浓度为2.23g/L时,胞外多糖产量最高,达0.749g/L.     

Experimentally induced cartilaginous fractures (osteochondritis dissecans) in foals fed low-copper diets

Four Thoroughbred foals were weaned from their dams when they were 1 day old and were fed a liquid milk-replacer diet containing approximately 1.7 micrograms of copper/g from plastic buckets for 4 to 7 months. They were kept in stalls with fiberglass walls and asphalt floors covered with rubber pads. Serum copper and zinc concentrations were determined 3 times/week by atomic absorption spectrophotometry, and liver copper and zinc concentrations were determined similarly after acid digestion of tissues taken at necropsy. The amount of soluble collagen in articular cartilage and aortic tissue was determined after necropsy. Clinical signs of illness, particularly evidence of lameness, were monitored daily. The foals were weighed weekly, and growth rate was monitored by measurement of height at the withers. Packed cell volumes and total and differential WBC counts were measured each time blood was drawn for copper and zinc concentration determinations. The foals were examined by necropsy at the end of the experiment, and the tissues were examined histologically. The foals developed intermittent, but nondebilitating, diarrhea with the onset of low serum copper concentrations. Considering the totally liquid diet, the foals grew well. Serum copper concentrations decreased to less than 0.1 micrograms/ml in 13 to 16 weeks. Lameness was evident 2 to 6 weeks after serum copper concentrations decreased to their lowest value (less than 0.1 micrograms/ml). All foals developed stilted gaits and ultimately walked on the front of their hooves. Major hematologic changes and alterations of hair color were not evident. Soluble collagen of articular cartilage and aortic tissue increased from 340 to 600% greater than that of control foals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Kleingrass (Panicum coloratum L.) poisoning in sheep

Twenty-four lambs grazing pastures of Panicum coloratum developed photosensitization secondary to hepatic dysfunction. Lesions were necrosis of scattered hepatocytes, obstruction of small bile ducts and bile canaliculi by small aggregates of birefringent crystals, and accumulation of birefringent crystals in phagocytes within sinusoids. The number of crystals in livers of affected sheep varied, depending on the amount of time of exposure to toxic plants and severity of hepatic abnormalities. Crystals in the liver were soluble in acidified ethyl alcohol, acetic acid, pyridine, chloral hydrate, and methanol, but not in xylene, petroleum ether, diethyl ether, acetone, water, or cold ethyl alcohol. Crystals were not stained by oil red O. There was necrosis of epithelial cells in renal distal convoluted tubules, papillary muscles of the heart, and the adrenal cortex. Lesions of Panicum coloratum-associated disease are similar to those associated with photosensitization induced by Tribulus terrestris, Agave lecheguilla, and Nolina texana.     

Experimental Haemophilus somnus infection in pregnant cattle

Of five pregnant cows inoculated intravenously with 5 X 10(8) viable 'Haemophilus somnus', one aborted within 5 days and excreted 'H. somnus' from the vagina for a further 7 weeks. A second cow proceeded to full term parturition but both it and its apparently healthy calf persistently excreted 'H. somnus'. The other animals underwent normal full term calvings and 'H. somnus' was not isolated from them or their calves. Lesions attributable to 'H. somnus' were detected only in the aborted fetus which showed an acute generalized inflammatory cell response consistent with a systemic Gram-negative bacterial infection. 'H. somnus' was isolated from all fetal tissues, including the placenta. The fetus and placenta also showed evidence of damage prior to inoculation. The placental damage may have predisposed the fetus and placenta to infection with 'H. somnus'. The placental epithelial cells contained intracytoplasmic organisms with the morphological and antigenic properties of 'H. somnus'.     

Congenital portosystemic shunts in Maltese and Australian Cattle Dogs

SUMMARY Congenital portosystemic shunts were definitively diagnosed in 62 dogs over a period of 15 years. Maltese and Australian Cattle Dogs were significantly over-represented, accounting for 14 and 13 cases, respectively. Maltese invariably had a single extrahepatic shunt derived from the left gastric or gastrosplenic vein, whereas Cattle Dogs usually had large intrahepatic shunts involving the right liver lobes. The clinical syndromes resulting from anomalous portosystemic communications were indistinguishable in the 2 breeds. Fasting blood ammonia concentration was elevated in 20 of 22 dogs tested, providing a minimally invasive and effective means of diagnosis. Complete or partial shunt attenuation was performed successfully in all 9 Maltese and in 2 of 6 Cattle Dogs in which it was attempted.     

One way protection between equid herpesvirus 1 and 4 in vivo

Two groups each of six sibling ponies were exposed to sequential infections with equid herpesvirus 1 or 4 (EHV-1 or EHV-4) at four or five month intervals. Two exposures to EHV-4 did not significantly reduce virus shedding or pyrexia when the ponies were subsequently exposed to EHV-1. However, two sequential infections with EHV-1 completely protected against challenge with EHV-4. Virus neutralising antibody in each group did not increase until 21 days after primary exposure and was subtype specific. However, complement fixing antibody rose within seven days after inoculation with EHV-1, and 14 days after inoculation with EHV-4, and while the latter was subtype specific the former was directed against both EHV-1 and EHV-4. Interpretation of these findings in relation to vaccination is discussed.     

A phalangeal fusion defect and osteochondrosis dissecans with subluxation of the distal interphalangeal joints in a foal

A fusion defect of the proximal and middle phalanges of both hindlimbs, osteochondrosis dissecans of the distal interphalangeal joints of the forelimbs, and subluxation of all 4 distal interphalangeal joints occurred in a Standardbred filly. Lameness was the first abnormality noted and was observed at one week of age in the left forelimb and progressed until all 4 limbs were affected by 5 weeks of age. On radiographs of both forelimbs, the distal interphalangeal joints were subluxated with irregularity and lucency of subchondral bone. On radiographs of the distal hindlimbs, there was a subluxation of both distal interphalangeal joints and loss of the proximal interphalangeal joint spaces with fusion of the proximal and middle phalanges. The foal was euthanised. On necropsy, there were focal areas of erosion of articular cartilage in the distal interphalangeal joint of both forelimbs. The proximal and middle phalanges of both hindlimbs were fused. Histopathological examination of the distal interphalangeal joint of the right foreleg showed loss of articular cartilage and degenerative changes in the exposed subchondral bone.