猪隐秘杆菌型出血性坏死性脾炎

六月龄去势公猪表现昏睡、食欲不振、站立困难。尸检发现脾脏边缘呈多重出血灶。从脾脏、肾脏、肌肉和肝脏中分离出革兰氏阳性杆菌,对分离株(TO16177)的16S rDNA基因序列比较分析发现,其可能与未发表过的隐秘杆菌属HJ57-14E菌株(登记号:gi18873551)(比较675bp个碱基,相似性达99.7%)为同一个属。脾脏组织切片的组织学检查发现呈广泛性坏死和炎症,其中革兰氏阳性杆菌显而易见。肝脏中可见多病灶的坏死斑。免疫组织化学检测发现,分离株与抗化脓性隐秘杆菌属(Arcanobacterium pyogenes)和内氏放线菌(Actinomyces naeslundii)的多克隆抗体具有交叉反应,且与后者的交叉反应更强烈。相似的反应也见于扁桃体的化脓灶中分离株,偶尔也见于脾脏和淋巴结中的分离株。本研究结果表明,这种未公开发布的隐秘杆菌属的细菌会引起生长肥育猪多器官功能衰竭,而后继发急性出血性坏死性脾炎。     

Larger body size with higher predation rate

Abstract –  Many studies have reported that prey fish increase in body size with an increase in piscivore abundance, and this change may be explained mainly by two processes: release from intraspecific competition because of a reduction in the prey fish population and size-dependent selection by the piscivore. However, the evolutionary mechanism is not yet fully understood. Here, we first show the body-size dynamics of the semelparous gobiid fish Gymnogobius isaza , which is one of the prey fishes of the introduced largemouth bass, Micropterus salmoides . The data show the possibility that the goby body size might have changed in parallel to the number of largemouth bass from 1975 to 2002, which may be one of the best examples of the positive relationship between body size and predation rate. Furthermore, we explored a mathematical model to consider a body-size change of semelparous fish from an evolutionary viewpoint. The model provided the following qualitative predictions: (1) the optimal assimilation rate increases with predation pressure; (2) a rapid large-scale increase in predation pressure may exterminate the prey fish because of delayed evolution of the assimilation rate; and (3) the optimal assimilation rate increases when the prey fish is more likely to die through predation than through natural mortality or when it is difficult to grow larger because of low resource availability or insufficient foraging efficiency. Moreover, we propose a theoretical framework to evaluate the relative effects of ecological and evolutionary processes over the long term.     

Parasitoid wasps on <Emphasis Type="Italic">Epinotia granitalis</Emphasis> (Lepidoptera: Tortricidae) larvae

 Parasitism by parasitoid wasps on the larvae of Epinotia granitalis (Butler), which is a wood-injuring pest in coniferous plantations, was observed for 6 years in two plantation forests of Chamaecyparis obtusa (Sieb. et Zucc.) Endl. and Cryptomeria japonica (L.f.) D. Don that were adjacent to each other and consisted of trees of almost the same size. E. granitalis larvae were collected from early April to mid-May, then reared in glass bottles, and finally examined to determine whether or not the larvae had been parasitized. Five species of parasitoids were recorded; two of them were classified in Ichneumonidae, Campoplex spp. A and B, and others in Braconidae, Iconella repleta Papp, Bassus cingulipes Nees von Esenbeck, and Bracon spp. In all 6 years, parasitism was first observed around 20 April. Species composition of parasitoids differed greatly among years and between forests. In 1 year in each forest the percentage parasitism increased significantly with the sampling date, indicating that not all parasitoids attack the same developmental stage of E. granitalis. The mean percentage parasitism per year was significantly higher in the forest of C. obtusa [11.5(%) ± 5.7(SD)] than in the forest of C. japonica (3.0 ± 4.1). These results suggest that the efficiency of parasitoid adults in finding hosts differed between the two forests. Received: September 20, 2001 / Accepted: August 5, 2002 Acknowledgments We are grateful to Dr. K. Maeto, Shikoku Research Center, Forestry and Forest Products Research Institute, and to Dr. K. Konishi, National Agricultural Research Center for Hokkaido Region, for identifying parasitoids, and to Dr. T. Miyaura, Forest Tree Breeding Center, and Dr. H. Kosaka, Forestry and Forest Products Research Institute, for their helpful advice throughout the study. Correspondence to:K. Kato     

Comparative functional anatomy of hindlimb muscles and bones with reference to aquatic adaptation of the sea otter

Although the sea otter (Enhydra lutris) is a complete aquatic species, spending its entire life in the ocean, it has been considered morphologically to be a semi-aquatic animal. This study aimed to clarify the unique hindlimb morphology and functional adaptations of E. lutris in comparison to other Mustelidae species. We compared muscle mass and bone measurements of five Mustelidae species: the sea otter, Eurasian river otter (Lutra lutra), American mink (Neovison vison), Japanese weasel (Mustela itatsi) and Siberian weasel (M. sibirica). In comparison with the other 4 species, E. lutris possessed significantly larger gluteus, popliteus and peroneus muscles, but smaller adductor and ischiopubic muscles. The popliteus muscle may act as a medial rotator of the crus, and the peroneus muscle may act as an abductor of the fifth toe and/or the pronator of the foot. The bundles of the gluteus superficialis muscle of E. lutris were fused with those of the tensor fasciae latae muscle and gluteofemoralis muscles, and they may play a role in femur abduction. These results suggest that E. lutris uses the abducted femur, medially rotated crus, eversion of the ankle and abducted fifth digit or extended interdigital web as a powerful propulsion generator. Therefore, we conclude that E. lutris is a complete aquatic animal, possessing differences in the proportions of the hindlimb muscles compared with those in other semi-aquatic and terrestrial mustelids.     

Therapeutic antibodies: their mechanisms of action and the pathological findings they induce in toxicity studies

Antibodies can swiftly provide therapeutics to target disease-related molecules discovered in genomic research. Antibody engineering techniques have been actively developed and these technological innovations have intensified the development of therapeutic antibodies. From the mid-1990’s, a series of therapeutic antibodies were launched that are now being used in clinic. The disease areas that therapeutic antibodies can target have subsequently expanded, and antibodies are currently utilized as pharmaceuticals for cancer, inflammatory disease, organ transplantation, cardiovascular disease, infection, respiratory disease, ophthalmologic disease, and so on. This paper briefly describes the modes of action of therapeutic antibodies. Several non-clinical study results of the pathological changes induced by therapeutic antibodies are also presented to aid the future assessment of the toxic potential of an antibody developed as a therapeutic.     

Life history and ecology of the glowbelly <Emphasis Type="Italic">Acropoma japonicum</Emphasis> in the Uwa Sea,Japan

ABSTRACT:   The life history and ecology of the glowbelly Acropoma japonicum a commercially important fishery resource, were investigated in the Uwa Sea, Japan. Newly settled juveniles (0⁺) appeared at the end of the breeding season and reached maturity in the next season, i.e. when they became yearlings (1⁺). The yearlings made a gametic effort comparable to that of older fish. During the breeding season, the somatic conditions were more deteriorated for males than for females. That the deterioration of male somatic conditions was not attributable to a sexual difference in energy gain from feeding suggests that the males incurred higher energetic costs of reproduction despite their relatively low gonadosomatic indices. Such an energy depletion may increase the mortality risk, resulting in female-biased sex ratios in the older age classes. Most of the 1⁺ fish disappeared in winter following their first breeding. For A. japonicum , the observed precocity and short life span is notable because it is a higher consumer that is generally expected to show later maturation and longer life. As possible explanations for their disappearances, predation and postbreeding emaciation were less likely. While fishing is one of the most influential factors, the possibility of age-specific migration toward deeper waters remains to be examined.     

Filtering method for obtaining stock indices by shark species from species-combined logbook data in tuna longline fisheries

ABSTRACT:   A method of filtering logbook data to obtain estimates of catch per unit effort (CPUE) for sharks has been proposed which simultaneously addresses the issues of under-reporting and the lack of species-specific catch records in historical data. Logbook catch data from vessels with high shark reporting rates are used to represent catch rates for the abundant blue shark Prionace glauca and low reporting vessels' data are used for the main commercially valuable species, the shortfin mako Isurus oxyrinchus . Logbook reporting rate filter (RRF) levels are evaluated through analytical and model-based comparisons to species-specific logbook records available since 1994 and shipboard observer data. At the high reporting rates, the ≥ 80% filter avoids large numbers of false zeros and provides the best fit to observer data for blue shark. At the low reporting rates, the ≤ 40% filter best matches the observer data for makos, but this filter level includes large numbers of false zeros and sharks of other species. The ≤ 20% filter produces a dataset that is better targeted to mako catches but considerably under-estimates CPUE relative to observer records. For these reasons, other means of estimating mako catch rates are suggested for further research.