Influence of death struggle on the structural changes in chub mackerel muscle during chilled storage

ABSTRACT: Chub mackerel (34–35 cm, approximately 500 g), which were caught by fishing with a rod and line at the Bungo Channel, Oita prefecture, were rested overnight in a fish preserve and either killed by decapitation (control group) or allowed to struggle in air for 30 min (struggled group). Muscle samples were excised every 4 h, and measurements on breaking strength and histological observations were done for both groups. The breaking strength of muscle in the control group was significantly higher than that in the struggled group, whereby a decrease in breaking strength was delayed for 12 h compared to the struggled group. Light microscopy showed space extension among muscle cells in association with a decrease in breaking strength. Especially in the struggled group, the extended area was larger and the difference in area was significant at the time when breaking strength showed a significant difference. Using electron microscopy, the extended area showed cut and/or disappeared collagen fibrils. From these results, it was demonstrated that struggling to death promoted the degradation of collagen fibrils and the weakening of connective tissue and, resultantly, led to the faster softening of muscle of chub mackerel.     

Rice <Emphasis Type="Italic">terpene synthase 18</Emphasis> (<Emphasis Type="Italic">OsTPS18</Emphasis>) encodes a sesquiterpene synthase that produces an antibacterial (<Emphasis Type="Italic">E</Emphasis>)-nerolidol against a bacterial pathogen of rice

Plant volatile compounds, including terpenes, are known to be involved in the rice defense system. In the present analysis of a terpene synthase, OsTPS18, in rice, we found that OsTPS18 was localized in the cytoplasm and synthesized the sesquiterpenes (E)-nerolidol and (E)-β-farnesene. The amounts of (E)-nerolidol and (E)-β-farnesene increased after jasmonic acid (JA) treatment. (E)-Nerolidol had significant antibacterial activity against Xanthomonas oryzae pv. oryzae (Xoo). These results suggest that (E)-nerolidol plays an important role in JA-induced resistance against Xoo and that it functions as an antibacterial compound in rice.     

Effect of ovary lipid of skipjack tuna on rat serum components after stress application

Lipid extracted from the ovary of skipjack tuna by the method that we developed is rich in phospholipid-type docosahexaenoic acid. The ovary lipid of skipjack tuna (OLS) was studied for its anti-stress activity in male Wistar rats, focusing on stress-related blood components: recovery from stress was examined after application of water immersion restraint stress. As a result, serum corticosterone (CORT) secretion was inhibited and decreased rapidly after stress application in rats given OLS compared with control rats. As CORT acts as a glucocorticoid, non-esterified fatty acid (NEFA) is expected to increase by stress application. However, the concentration tended to be lower in rats given OLS than in control rats. With respect to OLS concentration, OLS increased serum dehydroepiandrosterone, secretion concentration-dependently. In addition, as with the recovery study, it tended to inhibit the increase in NEFA. These results indicate that OLS may have an anti-stress activity against acute stress.     

Expression and functional analysis of chemokine receptor 7 in canine lymphoma cell lines

C-C chemokine receptor 7 (CCR7) contributes to cell homing to lymph nodes (LNs). Recent studies reported that CCR7 is also expressed in tumor cells, which correlates with LN metastasis in various cancers. However, the expression of CCR7 in tumor cells is unknown in dogs due to the lack of appropriate antibodies. In the present study, a fusion protein of C-C chemokine ligand 19 (CCL19) was employed as an alternative method to CCR7 antibodies. The fusion CCL19 protein specifically detected CCR7 expressed in canine lymphoma cell lines, which showed active chemotaxis to both canine and mouse ligands. The present study will help further research on the involvement of canine CCR7 in LN metastasis.     

Cytotoxicity for porcine islet cells by complement of six animal species

Complement-mediated cytotoxicity for porcine islet cells (PICs) was evaluated using sera of six animal species. Then soluble complement receptor type-1 (sCR1) as an anti-complement agent was added to those sera, and the changes in 50% hemolytic unit of complement serum (CH50) and cytotoxic effect of those sera on PICs were examined. All the sera except for that of pig showed cytotoxicity. However, the extent of toxicity was considerably different between species. In the rat and human serum, sCR1 significantly reduced CH50 and cytotoxicity, however in the dog serum, sCR1 had no suppressive effects. These results may suggest that complement contribute to humoral cytotoxicity for PICs as a main factor, and the compatibility of complement with PICs differs between animal species.     

Characterisation of cross-reactivity of virus neutralising antibodies induced by feline panleukopenia virus and canine parvoviruses

It was recently reported that canine parvoviruses (CPV) had entered cat populations and induced disease in infected cats, while they had affected only dogs in the past. It is important to determine whether conventional feline panleukopenia virus (FPLV) vaccines protect against recent CPV infections. In this study, the cross-reactivity of virus-neutralising (VN) and haemagglutinin-inhibition (HI) antibodies in cats induced by FPLV and CPV s were examined. Lower cross-reactivities of VN and HI antibodies against each CPV strain were observed in cats experimentally inoculated with FPLV or vaccinated with an inactivated FPLV vaccine. In addition, we revealed the existence of a novel type of FPLV, which reacted weakly with antibodies induced by the conventional FPLV vaccine.     

Fine structure of atrial natriuretic peptide(ANP)-granules in the atrial cardiocytes in the pig, cattle and horse.

In the pig, cattle and horse, the right and left atria and ventricles were examined by immunohistochemistry, and the right atrial and auricular cardiocytes were studied by transmission electron microscopy. Moreover, ANP-granules in the cardiocytes were analyzed by ultrastructural morphometry. Immunohistochemically, the most intensely ANP-reacted cardiocytes were localized in the right auricle, particularly more prominent in the pig and cattle than in the horse. Ultrastructurally, ANP-granules were located principally in the perinuclear region associated with the Golgi apparatus and throughout the sarcoplasmic layers. They were classified into 2 types, A and B. A-granule had a conspicuous electron-dense core enveloped by a membrane. B-granule had a fibrillogranular core enveloped by an indistinct membrane. By TEM equipped with a goniometer stage, a part of the limiting membrane of B-granules became visible as the stage tilt progressed. By ultrastructural morphometry, the number of each type of granules was significantly greater in the pig and cattle than in the horse. In the pig and cattle, the total number of both types of granules in the auricular cardiocytes was significantly greater than that in the atrial ones. The diameter of each type of granules was significantly larger in the pig and cattle than in the horse. The diameter of A-granules was significantly larger than that of B-granules.