Prevalence of Fimeria funduli (Protozoa: Eimeriidae) in the Longnose Killifish Fundulus similis from Horn Island, Mississippi

Eimeria funduli occurred in Fundulus similis from Horn Island, Mississippi, during 1980, in contrast with its apparent absence during 1978 and 1979. Prevalence of the parasite appears to be related to the unusually low salinity in Mississippi Sound, and in ponds and off the beaches of Horn Island. The low salinity may have promoted the migration of infective intermediate hosts from inshore waters to the island

Exocrine Pancreatic Neoplasms in the Mummichog (Fundulus heteroclitus) from a Creosote-Contaminated Site

A high prevalence of exocrine pancreatic neoplasms occurred in mummichog, Fundulus heteroclitus, from a creosote-contaminated site in the Elizabeth River, Virginia. A total of 20 neoplasms were found in a group of about 1,300 fish obtained at this site over a 2-yr period. Of 240 fish collected during October 1991, 3.3% had pancreatic neoplasms. Adjusted total lesion prevalence for large adult fish (Size Class III: total length = 75–85 mm; Size Class IV: total length \u3e 85 mm) was 6.7%. Pancreatic neoplasms were not observed in 234 fish collected at this site during May 1991, nor were they found in 420 fish obtained during fall 1991 from 1 uncontaminated and 6 moderately contaminated localities. Lesions involved both mesenteric and intrahepatic exocrine pancreas and ranged from well-differentiated acinar cell adenomas to poorly differentiated acinar cell carcinomas. One fish had an atypical acinar cell focus. All specimens with pancreatic neoplasms also had hepatocellular lesions. This epizootic of exocrine pancreatic neoplasia is the first to be reported in a wild fish population. Based on chemical characterization of the site and limited experimental data on chemically induced pancreatic carcinogenesis in other small fish species, the neoplasms were probably caused by exposure of the mummichog to chemical carcinogens in their environment

Host Specificity of \u3ci\u3eCalyptospora funduli\u3c/i\u3e (Apicomplexa: Calyptosporidae) in Atheriniform Fishes

Calyptospora funduli has a broad host specificity, infecting at least 7 natural and 10 additional experimental definitive hosts, all atheriniform fishes within 5 families, but most in the genus Fundulus. Barriers, apparently innate ones, prevent any development of C. funduli in perciform fishes but allow incomplete or abnormal development of the parasite in a few unnatural atheriniform hosts. In the freshwater species Fundulus olivaceus and Fundulus notti, these abnormalities consisted of asynchronous development, degeneration of the parasite in early stages of development, and the formation of numerous macrophage aggregates. Rivulus marmoratus has the ability to eliminate infections with a granulomatous inflammatory response. Additional barriers that limit natural infections of C. funduli in other hosts include feeding behavior, environmental conditions, and geographic isolation

Prevalence of Fimeria funduli (Protozoa: Eimeriidae) in the Longnose Killifish Fundulus similis from Horn Island, Mississippi

Eimeria funduli occurred in Fundulus similis from Horn Island, Mississippi, during 1980, in contrast with its apparent absence during 1978 and 1979. Prevalence of the parasite appears to be related to the unusually low salinity in Mississippi Sound, and in ponds and off the beaches of Horn Island. The low salinity may have promoted the migration of infective intermediate hosts from inshore waters to the island

Phylogeny of fish-infecting Calyptospora species (Apicomplexa: Eimeriorina)

There are numerous species of apicomplexans that infect poikilothermic vertebrates, such as fishes, and possess unique morphological features that provide insight into the evolution of this important phylum of parasites. Here, the relationship of the fish-infecting Calyptospora species to other coccidians was investigated based on DNA sequence analysis. Genetic data from the small subunit ribosomal DNA region of the genome were obtained for three of the five nominal species in the genus Calyptospora. Phylogenetic analyses supported a monophyletic lineage sister to a group composed of mostly Eimeria species. The monophyly of Calyptospora species supports the validity of the family Calyptosporidae, but the sister relationship to Eimeria species might also suggest the Eimeriidae be expanded to encompass Calyptospora. The validity of the family Calyptosporidae has been questioned because it is delineated from the Eimeriidae largely based on life cycle characteristics and sporocyst morphology. In general, Eimeria species have a homoxenous life cycle, whereas the type species of Calyptospora is heteroxenous. In the absence of experimental transmission studies, it may be difficult to demonstrate whether all Calyptospora species are heteroxenous. Other distinct morphological characteristics of Calyptospora such as an incomplete sporocyst suture, an apical opening for sporozoite release, a thin veil surrounding sporocysts supported by sporopodia, and a lack of Stieda and sub-Stieda bodies suggest there may be adequate features to delineate these taxa. Even without life cycle data for all species, the morphology and genetic data provide a means to reliably classify Calyptospora species. Placement in either the Calyptosporidae or Eimeriidae is discussed, along with issues relating to the phylogeny of the genus Goussia

Fundulus as the premier teleost model in environmental biology : opportunities for new insights using genomics

Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Comparative Biochemistry and Physiology Part D: Genomics and Proteomics 2 (2007): 257-286, doi:10.1016/j.cbd.2007.09.001.A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these species. We suggest that a more complete genomics toolbox for F. heteroclitus and related species will permit researchers to exploit the power of this model organism to rapidly advance our understanding of fundamental biological and pathological mechanisms among vertebrates, as well as ecological strategies and evolutionary processes common to all living organisms.This material is based on work supported by grants from the National Science Foundation DBI-0420504 (LJB), OCE 0308777 (DLC, RNW, BBR), BES-0553523 (AW), IBN 0236494 (BBR), IOB-0519579 (DHE), IOB-0543860 (DWT), FSML-0533189 (SC); National Institute of Health NIEHS P42-ES007381(GVC, MEH), P42-ES10356 (RTD), ES011588 (MFO); and NCRR P20 RR-016463 (DWT); Natural Sciences and Engineering Research Council of Canada Discovery (DLM, TDS, WSM) and Collaborative Research and Development Programs (DLM); NOAA/National Sea Grant NA86RG0052 (LJB), NA16RG2273 (SIK, MEH,GVC, JJS); Environmental Protection Agency U91620701 (WSB), R82902201(SC) and EPA’s Office of Research and Development (DEN)

Ultrastructure of the Interface Between Stages of \u3ci\u3eEimeria funduli/i\u3e (Apicomplexa) and Hepatocytes of the Longnose Killifish, \u3ci\u3eFundulus similis\u3c/i\u3e

The interface between stages of Eimeria funduli and hepatocytes of the experimentally infected killifish Fundulus similis was studied ultrastructurally. Parasitophorous vacuoles (PV\u27s) in which meronts, macrogamonts, and microgamonts developed were lined by an inner, smooth membrane and an outer, ribosome-studded membrane. The outer membrane bordered on the cytoplasm of the host cell, whereas the inner one limited the PV. The origins of these membranes have not been determined with certainty, but images were observed in which both membranes appeared to be continuous with the outer nuclear membrane of the host cell. Furthermore, the outer PV membrane was continuous with membranes of rough endoplasmic reticulum in the host cell. For stages which were rapidly growing or differentiating, the inner membrane blebbed into the PV. Blebbing ceased and ribosomes detached from the outer membrane after maturation of the meront or fertilization of the macrogamont. Blebbing appears to be a mechanism by which nutrients transfer from the host to the parasite. During sporogony, the inner PV membrane acquired a thin layer of electron dense material, but otherwise membranes lining the PV remained intact. The two PV membranes, probably together with dense material of parasitic origin lining the inner membrane, appear to serve as the oocyst wall enclosing the sporocysts until they are released in the intermediate host

Organization of Sporulated Oocysts of \u3ci\u3eEimeria funduli\u3c/i\u3e in the Gulf Killifish, \u3ci\u3eFundulus grandis\u3c/i\u3e

Oocysts of Eimeria funduli were studied by transmission electron microscopy in naturally-infected livers of the Gulf killifish, Fundulus grandis. Tissues were cryo-processed because membranous structures in the oocyst appear to hinder routine fixation and embedment. The oocyst wall (about 25 nm thick) was adjacent to the host cell and consisted of an outer membrane that limited the host cell cytoplasm and an inner membrane separated from the outer membrane by a narrow space. In some specimens, dense material was applied to the inner face of the inner membrane. Individual sporocysts were surrounded by a membranous veil (about 25 nm thick) that consisted of two unit membranes. Sporopodia, projections of the sporocyst wall, supported the veil. The sporocyst wall (130-150 nm thick) consisted of two layers, a thin electron-lucent outer layer (about 10 nm thick) and a thick electron dense inner layer (about 130 nm thick). Depending on the plane of section, the inner layer had transverse striations with periods of 3 to 4 nm or 12 to 15 nm. A narrow fissure, broadest at the anterior pole of the sporocyst, extended about one-third the length of the sporocyst wall. The posterior pole of the sporocyst was characterized by a bulbous swelling. Although this swelling resembled a Stieda body in light microscopic preparations, ultrastructurally, the swelling was a knoblike thickening in the sporocyst wall and did not plug a gap in this wal

Exocrine Pancreatic Carcinogenesis in the Guppy Poecilia reticulata

Exocrine pancreatic neoplasms developed in the guppy Poecilia reticulata following exposure to the direct-acting carcinogen methylazoxymethanol acetate (MAM-Ac). Fish 6 to 10 d old were exposed to nominal, non-toxic concentrations of 4 and 10 mg MAM-Ac l(-1) for 2 h and then transferred to carcinogen-free water for grow-out. Whole specimens were sampled monthly up to 9 mo post-exposure to follow the histologic progression of the lesions. No neoplasms occurred in 119 control specimens examined. Pancreatic acinar cell adenomas and carcinomas occurred in 42 of 243 (17%) of the specimens exposed to MAM-Ac. As in earlier studies, specimens exposed to the low MAM-Ac concentration exhibited a higher pancreatic neoplasm incidence (27.8%) than those exposed to the high concentration (7.8%). Acinar cell adenomas accounted for 27 of the 42 neoplasms. Adenomas exhibited a high degree of acinar cell differentiation and some contained foci of atypical acinar cells that were less differentiated and more basophilic than were surrounding adenoma cells. Carcinomas occurred in 15 specimens and exhibited a range of cellular patterns, Although no distant metastases were found, carcinomas tended to invade neighboring tissues and organs, The occurrence of carcinogen-induced pancreatic neoplasms in guppies strengthens the usefulness of small fish species in carcinogen testing and provides an additional model for studying pancreatic neoplasia

Life Cycle of \u3ci\u3eCalyptospora funduli\u3c/i\u3e (Apicomplexa: Calyptosporidae)

The taxonomic status of the extraintestinal piscine coccidium Calyptospora funduli is based in part on its requirement of an intermediate host (the daggerblade grass shrimp Palaemonetes pugio). In the present study, grass shrimp fed livers of Gulf killifish (Fundulus grandis) infected with sporulated oocysts of C. funduli exhibited numerous sporozoites suspended in the intestinal contents when fresh squash preparations were examined by light microscopy. Using this method, sporozoites were not seen in intestinal epithelial cells of the grass shrimp or in any other cell types. Ultrastructural examination, however, revealed sporozoites in the cytoplasm of the gut basal cells. Cross-sections of 1-13 sporozoites were seen within a single cell, and those sporozoites each appeared to be situated in individual membrane-bound vesicles, rather than in a single parasitophorous vacuole. These ultrastructural observations indicate that in the grass shrimp intermediate host, sporozoites that develop into an infective stage probably undergo that development in gut mucosal basal cells. Prior studies revealed that these sporozoites modified their structure over 4-5 days and that before that time, they were not infective to the fish host. Following ingestion of an infected shrimp by a killifish, the infective sporozoites apparently reach the liver of their killifish definitive hosts through the bloodstream. Sporozoites were seen in blood smears from the longnose killifish, Fundulus similis, 4 hr after fish were fed experimentally infected grass shrimp. Additionally, coccidian trophozoites and early meronts were seen in hepatocytes from several longnose killifish at 48, 72, and 96 hr postinfection. This study, in conjunction with previous findings, clearly confirms that a true intermediate host is required in the life cycle of C. funduli, that a developmental period of about 5 days in grass shrimp is necessary for sporozoites to become infective to killifishes, and that sporozoites do occur intracellularly in gut basal cells of the grass shrimp