摘要:

Abstract.Histopathological studies on natural and experimental infections of nineteen microsporidian species from fishes distinguished two types of tissue reactions.The first type is characteristic of infections with xenoma‐inducing microsporidian species and comprises three successive stages: a weakly reactive stage, a productive stage with the formation of granulomas and a stage of granuloma involution. Following the first stage, tissue reactions are directed towards the isolation of the parasite and result in its complete elimination and host tissue repair. The extent of pathological changes probably depends on the number of parasite cells which initiated the infection.The second type is represented byPleistophoraspecies infecting muscles or oocytes. Host tissue reaction is surprisingly slight during the schizogony and sporogony and does not tend to isolate the invaded muscle fibres. A slight lymphocytic infiltration of myosepta indicates the first stage of tissue reaction. The tissue reaction only reaches the productive stage when mature spores completely fill the contents of the infected muscle fibre. A thick wall of fibroblasts may be formed to demarcate the parasite mass as soon as it undergoes necrotic changes. The extent of pathological changes probably depends on the ability of early developmental stages of the parasite to spread the infection within the host.In both types of tissue reaction, the spores are destroyed by complete digestion within host phagocytic cell

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1980.tb00398.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.The circulating haemocytes of the tanner crab,Chionocetes bairdi, were studied and classified as hyalinocytes, intermediate granulocytes and eosinophilic granulocytes. Differential haemocyte counts of normal crabs and crabs infected with an apparently pathogenic unnamed ascomycete fungus revealed a shift in the hyalinocyte‐granulocyte ratio in infected crabs. There was a highly significant increase in the percentage of granulocytes and a corresponding decrease in hyalinocytes in infected crabs. This shift was thought to be caused by a marked increase in the relative number of eosinophilic gianulocytes. There was also a highly significant statistical relationship between the severity of the internal fungus infection, established by histopathological analysis of the major organ systems, and the increased number of circulating eosinophilic granulocytes. The results of the study indicate that differential haemocyte counts may be a valuable tool in monitoring the health ofC. bairdipopulation

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1980.tb00399.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.A normally free‐living hymenostomatid ciliate was found to be the cause of heavy infections of gills, viscera and body muscle in Atlantic and Pacific marine fishes kept in the New York Aquarium. Of special interest is the fact that the parasites, usually with food vacuoles filled with blood cells and cellular debris, caused extensive damage to the body muscle; the other infected organs showed no characteristic tissue reactions. The immediate cause of death is attributed to the exceptional load of the parasite on the gills, thus interfering with normal respiratory function.The ciliate, isolated from a recent outbreak, is described in detail, and shows many characteristics ofUronema marinumDujardin, a species that has been reported as free‐living in salt water; the form reported here differs from the type and other members included in this species, by the presence of less than three rows of bipolar meridians. This facultative parasite is described in detail and compared with other gen

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1980.tb00400.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.A vacuum degassing apparatus was used to subject channel catfishIctalurus punctatus(Rafinesque) to sublethal hypoxia for 24, 48 or 72 h. Spleen, liver, gills, anterior kidney and posterior kidney from the catfish exhibited histopathological changes that included necrosis, hyperaemia, oedema, haemorrhage, hyperplasia and hypertrophy. Of the organs examined, gills were most affected by the hypoxic conditions. After 5 days of reacclimatization to normoxic conditions, channel catfish continued to exhibit histopathological effects of prolonged hypoxia.

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1980.tb00401.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.Pleistophora typicalisGurley, 1893, a parasite of the striated muscle ofMyoxocephalus scorpiushas been re‐examined at light‐ and electron‐microscope levels. Foci of infection were almost exclusively found in the ventral body wall where a mixture of schizonts, sporonts and masses of pansporoblasts lay in direct contact with unaltered host myofibrils and mitochondria.All stages were surrounded by a thick (0‐5 μm) amorphous coat, external to the plasmalemma. In schizonts this was traversed by channels passing from the plasma‐lemma to a layer of vesicles in contact with the muscle. This coat became modified as a pansporoblast envelope surrounding the mature spores: at first a layer of fine granules was laid down about mid‐way across the previously amorphous coat, while the channels disappeared. At the time when the sporogonial plasmodium retracted away from the coat to produce the pansporoblast cavity, the layer of the coat within the granules disintegrated into spherical vesicles. The pansporoblast envelope around the mature spores was composed of two or three layers of different electron density, including one which was strongly electron dense. The pansporoblast envelope as defined here corresponds in function, but not necessarily in origin, to the sporophorous vesicle that encloses the spores in other pansporoblastic microsporidia.Schizonts had an extensive system of smooth endoplasmic reticulum, composed of expanded vesicles and divided by plasmotomy into smaller multinucleate segments. The endoplasmic reticulum of sporogonial stages was comprised of a network of fine channels, parallel arrays of flat cysternae and close‐packed stacks of membranes. The sporogonial plasmodium divided stepwise through smaller multinucleate segments into uninucleate sporoblasts. Nuclei were isolated throughout development.Two types of sporonts were recognized: large sporonts gave rise to pansporoblasts containing up to 200 microspores. Macrospore pansporoblasts always contained eight macrospores. Microspores measured 4–4 × 2·3 μm (fresh) and were probably uninucleate. Macrospores measured 7·5 × 3·0 μm (fresh) and were probably binucleate.Another microsporidium, found in the muscles ofBlennius pholis, which had been attributed to the same species by Thélohan (1895), was distinguished on the basis of spore size (microspores 3·9 × 2·3 μm and macrospores 7·7 × 3·8 μm fresh) and by the fact that electron dense components were laid down in the pansporoblast wall early in sporogony. The species was

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1980.tb00402.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.Bacteriologically sterile filtrates of ‘tumorous’ fish elicited formation of ‘tumours’in vivowhich were morphologically indistinguishable from those described by Wessing&Bargen (1959). Attempts to isolate the putative aetiologic ‘Virus’ in primary and established cell cultures failed. When the lesions were examined for other compatible aetiologies, acid‐fast stains revealed acid‐fast bacilli and cultures grewMycobacterium fortuitum. It is suggested that the ‘kidney tumour virus’ is actually soluble mycobacterial cell‐fractions capable of eliciting tube

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1980.tb00403.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1980.tb00404.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1980.tb00405.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Book reviewed in this article:Sea microbes. By J. M. Siebueth.Farming the flat oysters of the genusOstrea.By P. Korringa.Animal Tissue Techniques. By G. L. Humason. 4th Edn.Reef Fishes of the Sea of Cortez: The Rocky‐Shore Fishes of the Gulf of California. By D. A. Thomson, L. T. Findleyand A. N. Kerstitch.Tissues and Organs Text‐Atlas of Scanning Electron Microscopy. By R. G. Kesseland R. H. Kar

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1980.tb00406.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY