Granulomatous lymphadenitis associated with Actinobacillus pleuropneumoniae serotype 2 in slaughter barrows

This study evaluated the occurrence of granulomatous lymphadenitis and its association with Actinobacillus spp. in 151 653 slaughtered pigs. Markedly enlarged pulmonary hilar, mediastinal, mandibular or hepatic lymph nodes were detected in 6 castrated males. The cut surfaces showed multifocal yellow-white lesions. Histologically, gram-negative bacilli were visible in the centers of the lesions with asteroid bodies, epithelioid cells, and multinucleated giant cells. Dense fibrous connective tissue surrounded these granulomatous lesions. Immunohistochemically, the organisms reacted with polyclonal antibodies against Actinobacillus pleuropneumoniae serotype 2 in all 6 barrows. The organism was isolated from the lymph nodes of all 6 animals. The results indicate that the granulomatous lymphadenitis was associated with A. pleuropneumoniae serotype 2 and the disorder had a tendency to occur in slaughter barrows.     

Anionic Trypsin from the Pyloric Ceca of Pacific Saury (Cololabis saira): Purification and Biochemical Characteristics

Anionic trypsin from Pacific saury (Cololabis saira) pyloric ceca was purified to homogeneity by ammonium sulfate precipitation, ion-exchange chromatography, and gel filtration chromatography. It was purified to 53.7-fold with a yield of 6.1%. The apparent molecular weight of the enzyme was about 24 kDa, as determined by size exclusion chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). On native-PAGE, trypsin showed a single band. The purified anionic trypsin displayed optimal activity at pH 8.5 and 55°C. The enzyme was stable at neutral and alkaline pH and in the temperature range of 20–50°C. The stability was affected by the calcium ion. The activity of purified anionic trypsin was completely inhibited by soybean trypsin inhibitor and N-p-tosyl-L-lysine chloromethyl ketone (TLCK) and partially inhibited by ethylenediaminetetraacetic acid (EDTA). NaCl (0–30%) decreased the activity in a concentration-dependent manner. The kinetic trypsin constants K_m and K_cat were 0.19 mM and 210 s^?1, respectively, while the catalytic efficiency (K_cat/K_m) was 1105.26 s^?1 mM^?1. The N-terminal amino acid sequences of anionic trypsin, IVGGYECQAH, were found and were homologous to those of trypsin from other fish species.     

Feeding events of Japanese lates <Emphasis Type="Italic">Lates japonicus</Emphasis> detected by a high-speed video camera and three-axis micro-acceleration data-logger

The feeding events of wild animals have been widely researched in recent decades. The use of invasive methods to determine stomach contents in which the fish is killed can, however, be considered to be unjustifiable in the case of an endangered fish, such as the Japanese late. Here, we report on a method that can be used to verify feeding events of a fish species without the need for killing the fish through the use of a high-speed video camera and a three-axis micro-acceleration data-logger. High-quality images obtained by the video showed that the fish opens its mouth with a quick downward movement of the mandibles and ingests prey via suction feeding. The movement of the mandibles was also simultaneously recorded by changes in the three-axis accelerations obtained by the logger attached to the dorsum. We attached the logger with an automatic release system to the dorsum of one captive Japanese lates and two wild fish together with an acoustic transmitter and then released the fish in the Shimanto River in Japan. After retrieving the logger, the movement records of the fish obtained by the three-axis accelerometer showed the same pattern of feeding events as those in captivity. A total of 13 feeding events at night and five during the daytime were obtained for the three fish during a total 129.7 h of recording.     

Mobility of the forearm skeleton in the Asiatic black (Ursus thibetanus), brown (U. arctos) and polar (U. maritimus) bears

In several primates and carnivores, pronation/supination angles of the forearm skeleton were examined, and it is thought that a larger angle is useful to acquire dexterous behaviors in feeding and/or life style, including climbing. In this study, the pronation/supination angles in Asiatic black, brown and polar bears were nondestructively examined. These specimens were classified as adult or non-adult. Three or four carcasses of each group of Asiatic black and brown bears were used for CT analysis, whereas only one adult polar bear was used. The forearms were positioned within the gantry of a CT scanner in both maximally supinated and pronated states. Extracted cross-sectional CT images of two positions were superimposed by overlapping the outlines of each ulna. The centroids of the radii were detected, and then the centroid of each radius and the midpoint of a line which connects between both ends of the surface of each radius facing the ulna, were connected by lines to measure the angle of rotation as an index of pronation/supination. In adult brown and polar bears, the angles were smaller as compared with the other groups (Asiatic black and non-adult brown bears). Asiatic black and non-adult brown bears can climb trees, whereas adult brown bears and polar bears cannot. This suggests that the pronation/supination angle is related to arboreal activity in Ursidae.     

Histopathological Changes in the Pancreas from a Spontaneous Hyperglycemic Cynomolgus Monkey

Morphological and immunohistochemical examinations were carried out on the pancreas of a hyperglycemic 5-year-old male cynomolgus monkey. Body weight gradually decreased from 6 months before termination, accompanying a slight reduction in food consumption and anorexia for the last 2 days. The blood glucose level was markedly elevated when examined at termination. Histopathologically, in the exocrine pancreas, diffuse hyperplasia of centroacinar and intercalated duct cells and diffuse atrophy of acinar cells with sporadic apoptosis were observed, although most centroacinar and intercalated duct cells were proliferating cell nuclear antigen (PCNA)-positive in both the present case and age-matched control animals. In the endocrine pancreas, the islets tended to be hypertrophic, with an increase in insulin-positive cells in comparison with the age-matched control animals. PCNA-positive cells also tended to increase in the islets, although positive cells for phospho-histone H3, a marker for mitotic cells, were not detected in the endocrine and exocrine pancreas. Moreover, neither inflammation nor amyloidosis was noted in the islets. In conclusion, the present case probably suffered from early-stage type 2 diabetes mellitus, and it provides fundamental information concerning pancreatic histopathology under insulin-related derangement in monkeys.     

Inoculum effect of arbuscular mycorrhizal fungi on soybeans grown in long-term bare-fallowed field with low phosphate availability

ABSTRACT

Inoculation with arbuscular mycorrhizal fungi (AMF) can increase the growth of host plants, especially under condition of low phosphate (P) availability. Although this effect is shown relatively easily in simplified systems such as pot experiments, it is often hard to show in the field because of complicating factors such as competition with indigenous AMF. We conducted an AMF inoculation experiment with three Japanese soybean cultivars (Enrei, Misuzudaizu, and Akishirome) in an allophanic (Umbric Silandic) Andosol field under the long-term selective application of major nutrients (NPK and -P) and bare fallow. In the inoculation plots, introduced AMF were well colonized in soybean roots at flowering stage. In the -P plots, inoculation tended to increase the shoot dry weight of all the three soybean cultivars; this effect remained until harvest. Although a significant difference is not recognized, there was a tendency of residual effect on Enrei in the following year. In the NPK plots, inoculation did not significantly increase the shoot dry weight. We thought that in the -P plots, the long-term selective application of N and K and the long-term maintenance of bare fallow created the soil conditions of low P availability and poor native AMF. Thus, introduced AMF can benefit soybean growth and yield in the soil with low competitor AMF density and low phosphate availability.     

Sodium iodoacetate-induced experimental osteoarthritis and associated pain model in rats

Degenerative lesions were induced in the knee joint of Wistar rats by intraarticular injection of chondrocyte metabolism inhibitor mono-iodoacetate (MIA) at doses of 0, 0.3 or 3 mg/joint. Histopathological examination and the measurement of hind paw weight ratio as an index of joint pain by incapacitance tester were performed. Histological findings that are similar to those observed in human osteoarthritis (OA), such as disorganization of chondrocytes, erosion and fibrillation of cartilage surface, and subchondral bone exposure etc., were observed in a MIA-dose-dependent manner. Saflanin-O fast green staining revealed that marked diffuse reduction of proteoglycan in cartilage tissue of rats treated with MIA. The clinical scores of the joint pain were closely correlated to the grade of histological findings. We conclude that the present experimental model in combination with a novel dual channel weight averager would be very useful for the study of human OA, and could be applied for estimation of therapeutic effect of new anti-OA drugs.     

Discrimination between Virulent and Attenuated Isolates of Tomato mosaic virus by Restriction Fragment Length Polymorphism

The three missense mutations on the gene for the 130-K protein of Tomato mosaic virus (ToMV) L₁₁A have been thought to be responsible for the attenuation of its virulence. The Eco47I RFLP detecting the missense mutation at 2349 successfully discriminated L₁₁A and its derivative attenuated isolates from ToMV virulent ones. RFLP analysis and mismatch amplification assay detecting the missense mutations at 1117 and 2754, respectively, could not discriminate some of the attenuated isolates from the virulent ones. These results indicated that, of the three missense mutations, only the one at 2349 was conserved in all the L₁₁A-derivative attenuated isolates. Received 16 March 2001/ Accepted in revised form 22 June 2001