No abstract

The tidewater silverside, Menidia beryllina, and the hogchoker, Trinectes maculatus, vv-ere exposed to south Louisiana whole crude oil (WCO) and its watersoluble fractions (WSF) to assess histopathological effects on their gills, olfactory organ, and liver. Both fishes were exposed to 5 mg WCO/I, 100 mg WCO/1, 5% WSF, and 50% WSF. Additionally, M. beryllina was exposed to 100 mg WCO/1 with 20 ppm Terramycin® to study possible complications caused by bacteria. Exposure of M. beryllina lasted 21-30 days, whereas experiments using T. maeulatus continued for 38-60 days. Pathological changes in M. berylUna appeared by day 7 and became severe as experiments progressed to day 30. Histological alterations in the silverside included epithelial hyperplasia and fusion of gill lamellae, separation of respiratory epithelium from underlying tissue, hyperplasia of sustentacular cells of olfactory lamellae, necrosis of both neurosensory and sustentacular epithelium, extensive Iipid vacuolation in hepatocytes, and atrophy and necrosis of intrahepatic exocrine pancreatic nodules. Of the tissues examined, the pancreas served as the most specific pathological indicator of oil pollution. In T. maculatus, hepatocytes of exposed individuals did not become vacuolated, and, except for gills exposed to 100 mg WCO/1, response by gills in the other three tests remained limited to slight hyperplasia. Olfactory mucosa of the hogchoker exhibited severe necrosis of both neurosensory and sustentacular cells in the high concentrations of oil, but no damage in low concentrations. The intrahepatic pancreas offish exposed to all testconcentrations atrophied and became necrotic by the end of experiments. Limited studies using both Terramycin and a combination of Terramycin and WCO indicated lack of bacterial involvement in tissue damage in oil-exposed silverside, but the size of hepatic nuclei increased in the Terramycin-control fish, and the shape of Iipid vacuoles appeared unusual subsequent to exposure to the combination. Menidia beryllina became hyperactive and refrained from feeding for up to 6 h after the initial administration of oil, whereas T. maculatus apparently never fed, and it exhibited hyperactivity after all exchanges of sea water and fresh oil. Deaths appeared to correspond both to degree of pathological damage and to exposure-concentrations. Partial to complete recovery was observed in gills, olfactory organ, and pancreas of M. beryllina exposed to WCO or WSF for 20 days and tben maintained in oil-free sea water for 17 days.

No abstract

-We present prevalence of Bartonella spp. for multiple cohorts of wild and captive cetaceans. One hundred and six cetaceans including 86 bottlenose dolphins (71 free-ranging, 14 captive in a facility with a dolphin experiencing debility of unknown origin, 1 stranded), 11 striped dolphins, 4 harbor porpoises, 3 Risso's dolphins, 1 dwarf sperm whale and 1 pygmy sperm whale (all stranded) were sampled. Whole blood (n = 95 live animals) and tissues (n = 15 freshly dead animals) were screened by PCR (n = 106 animals), PCR of enrichment cultures (n = 50 animals), and subcultures (n = 50 animals). Bartonella spp. were detected from 17 cetaceans, including 12 by direct extraction PCR of blood or tissues, 6 by PCR of

No abstract

Ultrastructural studies were made on the inflammatory response in livers of two killifishes, Fundulus grandis and F. similis, experimentally infected with the coccidium Eimeria funduli. Coinciding with the formation and development of gamonts of E. funduli, changes took place in the liver and leucocytes appeared in that organ. Near areas of developing macrogamonts, many hepatocytes degenerated whereas others contained residual hodies which indicated sublethal damage. The damage was prohably associated with merozoite formation and release. Filament-rich perisinusoidal cells hypertrophied during the development of £". funduli and contributed to wailing off aggregates of oocysts from uninfected liver tissue. Leucocytes involved in the host response included lymphocytes, monocytes, heterophils, eosinophils and an unidentified third type of granulocyte. The heterophil was the first granulocyte to respond to the parasite and sometimes appeared to penetrate the parasitophorous vacuole of degenerating macrogamonts. Degranulating eosinophils were often observed near damaged tissues. Both the monocyte and eosinophil were phagocytically active. The monocyte was more phagocytically active and contained both host cells and parasite debris, whereas the eosinophil contained only debris from degenerating macrogamonts. The presence of immature granulocytcs in the liver suggests that at least some granulocyte formation occurred in the liver.

A strain of a colorless, filamentous bacterium (tentatively identified as Leucothrix mucor) heavily infests the brine shrimp, Artemia salina. Its ultrastructure, unlike that of some other strains, does not reveal a distinct middle layer between its outer cell wall layer and cytoplasmic membrane, irregular blebs extending from the cell layers, or an external sheath. An entire infestation, represented as a mat of the bacterium with associated debris and microorganisms, sloughs from the shrimp when exposed to a variety of treatments. Primarily because most effective treatments are toxic to the shrimp, 100 ppm terramycin provides the treatment of choice.

The ultrastructure of tiic macrogamont of Eimcriu fmuluii wns studied in hepatocytes of the kilhfish Fuucliiliis graiulis and F. .simiii.s. The macrogamont developed in a parasitophorous vacuole (PV) that was bounded by two unit membranes probably dei'ived from an envelope of modified host rough endoplasmic reticulum (RER). The membrane adjacent to the host-cell cytoplasm was lined with ribosomes. whereas the membrane facing the PV was smooth and blebbed into the PV. Intravacuolar tubules were not observed in the PV. The macrogamonts had a single limiting membrane with few micropores. Developing macrogamonts had abundant RER, few Golgi bodies, and a few smail polysaccharide granules. Nuclei of developing maerogamonts had dispersed chromatin and compact nucleoii. Polysaccharide granules in developing and mature macrogamonts were identified with the periodic acid-thiocarbohydrazide-silver proteinate technique. In mature macrogamonts, polysaccharide granules as large as 1 -2 /un in diameter nearly filled the cytoplasm. The cytoplasm contained three kinds of inclusions that were associated with either the RER or Golgi apparatus. Inclusions identified as type I wallforming (WE) bodies were small, dense, membrane-bound granules that developed from the Golgi appaiatus. Inclusions identified as type II WE bodies were usually dense, irregularly shaped bodies that occupied RER cisternae. Some type II WE bodies had a heteiogeneous content but most were homogeneous, A third type of inclusion was related to the cytoplasmic aspect of RER cisternae and consisted of tubules and vacuoles enclosed in a membrane.