Isolation of bovine coronavirus from feces and nasal swabs of calves with diarrhea.

Fecal and nasal samples were collected from 180 calves with diarrhea and 36 clinically normal co-habitants, and tested for virus using HRT-18 cell cultures derived from human rectal adenocarcinoma. A cytopathic virus was isolated from 5 fecal and 56 nasal samples obtained from diarrheic calves. All calves in which the virus was isolated from diarrheic feces were positive for virus isolation from nasal swabs. The virus was also isolated from the nasal swabs of 10 clinically normal calves that were co-habitants with diarrheic calves. Because they were morphologically similar to coronavirus, agglutinated mouse erythrocytes and serologically identical with the Nebraska calf diarrhea coronavirus, new isolates were identified as bovine coronavirus. The demonstration of viral antigens in nasal epithelial cells by a direct immunofluorescence was in close agreement with the virus isolation in HRT-18 cell cultures. This is the first report on the isolation of bovine coronavirus from newborn calves with diarrhea in Japan. The evidence that the virus was frequently isolated from nasal swabs is of great interest for understanding the pathogenesis of bovine coronavirus infection.     

Relationship between liver degeneration and the production of dark firm dry meat in slaughtered pigs

Sixty-five of 77 slaughtered pigs with liver degeneration produced dark firm dry (DFD) meat. The biochemical properties of blood, liver and muscle of those pigs were examined. In the blood, the NEFA level was higher, which indicated the mobilization of lipids from adipose tissues. The serum CPK and LDH5 levels were higher, the enzymes being derived from muscle. In the degenerative liver with yellowish discoloration, the TG level was higher and the glycogen level was lower than in a normal liver. In the DFD muscle with the final pH above 6.0, both the glycogen level immediately after slaughter and the lactic acid level 24 hr after slaughter were lower than in a normal muscle with the final pH below 6.0. Five pigs exhausted experimentally by 53-hr fasting and hard exercise showed the same changes in the blood and liver as the pigs with liver degeneration. Four of the 5 exhausted pigs showed the same changes in the muscle as in DFD meat. From these data, it was confirmed that exhaustion before slaughter led to lipid accumulation in the liver and to a decrease in muscle glycogen, and consequently caused both liver degeneration and DFD meat in the same pig.     

The Valine,Leucine and Isoleucine requirements of white leghorn chicks

1. The requirements for leucine, isoleucine and valine were determined in 8‐ to 18‐d‐old White Leghorn male chicks. The requirements were estimated from body‐weight gains.

2. The estimated requirements for leucine, isoleucine and valine were 200, 115 and 125 mg/bird d, or 12–0, 5.0 and 8.0 g/kg diet, respectively. In terms of concentration in the diet, they are broadly similar to results for broiler‐type chicks.

3. When body‐weight gain was plotted against daily intakes of each amino acid, significant (P < 0.01) quadratic regression equations were obtained. The equations showed some characteristics of the individual amino acids.     

Effects of oestradiol-17beta and testosterone on progesterone production in the cultured granulosa cells of Japanese quail

In order to study the effects of steroid hormones on steroidogenesis in the avian ovary, quail granulosa cells were cultured with follicle stimulating hormone (FSH), oestradiol-17beta or testosterone. The progesterone content of the medium during the culture period of 66 h and the following 3 h of incubation with luteinising hormone (LH), was measured by radioimmunoassay. When FSH, oestradiol-17beta or testosterone were added during the 66 h culture, subsequent progesterone production by the cells during 3 h of incubation with LH was significantly increased. However, testosterone also stimulated progesterone production in the medium during the 66 h culture period, whereas FSH oroestradiol-17beta did not. Addition of staurosporine during culture inhibited both LH-stimulated progesterone production and testosterone-stimulated progesterone production. These results indicate that the processes during which granulosa cells acquired responsiveness to LH, and testosterone stimulates progesterone production might both be mediated by a staurosporine-sensitive protein kinase C-dependent pathway in quail granulosa cells.     

Relationships between the damage to radish caused by the root-lesion nematode Pratylenchus penetrans, its density prior to cultivation and the soil nematode community structure evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis

A preliminary survey using 20 conventionally farmed fields in which fumigants have been applied every year showed that the root-lesion nematode Pratylenchus penetrans was distributed both in the upper (0–30 cm) and lower (30–60 cm) soil layers. In six of the 20 fields, P. penetrans was detected in the lower layers exclusively, suggesting that the most appropriate depth to sample soil is 0–60 cm to estimate the relationship between the density of P. penetrans and its damage to radish. There was a highly significant correlation ( r  = 0.923) between the density of P. penetrans in the 0–60 cm depth and the number of spots on a radish. No damage to radish was observed in soils with <2.5 individuals of P. penetrans per 20 g soil before cultivation. However, in cases in which the density of P. penetrans was 3.4–6.2 individuals per 20 g soil, the number of spots on a radish showed more variation (0–131.5 per radish) and there was no significant correlation between them. The nematode community structure of soils with 3.4–8 individuals of P. penetrans per 20 g soil, evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis, was significantly different ( anova , PC2, P  <   0.05) between soils with low (0–42) and high (more than 80) damage levels, suggesting that radish damage might be predicted on the basis of the prevailing soil nematode community structure.