A new species of amphizoic amoeba, Nuclearia pattersoni sp. n., isolated from gills of Rutilus rutilus L. is described. It is characterised by elongate flattened trophozoites of irregular shape. The longer dimension of their bodies is 13.2 (11.0-15.7) microm. Filopodia radiating mostly from the poles are 2 to 2.5 times longer than the body. The diameter of less frequently observed spherical trophozoites is 8.2-10.8 microm; their filopodia radiate to all directions. Cyst-like stages have shorter pseudopodia that arise from one pole only. The surface of locomotive forms from agar plate cultures has a thin amorphous glycocalyx, while most cells are covered by two layers of extracellular matrix. Mitochondria have flattened cristae, dictyosomes are located in the perinuclear zone. A conspicuous ultrastructural feature of the morphologically similar N. simplex, perinuclear striated band, is not present. Light microscopic and ultrastructural data are completed with the sequence of SSU rRNA gene and phylogenetic analysis including sequences of related taxa. The bacterial endosymbiont found in N. pattersoni type strain RR2G2 is assigned to the genus Rickettsia.

• MeSH
• Amoeba klasifikace   genetika   izolace a purifikace   ultrastruktura   MeSH
• Cyprinidae mikrobiologie   parazitologie   MeSH
• DNA bakterií genetika   MeSH
• DNA genetika   MeSH
• elektronová mikroskopie MeSH
• fylogeneze MeSH
• Rickettsia klasifikace   genetika   izolace a purifikace   MeSH
• sekvence nukleotidů MeSH
• symbióza MeSH
• žábry mikrobiologie   parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA bakterií MeSH
• DNA MeSH

Free-living amoebae infecting freshwater and marine fish include those described thus far as agents of fish diseases, associated with other disease conditions and isolated from organs of asymptomatic fish. This survey is based on information from the literature as well as on our own data on strains isolated from freshwater and marine fish. Evidence is provided for diverse fish-infecting amphizoic amoebae. Recent progress in the understanding of the biology of Neoparamoeba spp., agents responsible for significant direct losses in Atlantic salmon and turbot industry, is presented. Specific requirements of diagnostic procedures detecting amoebic infections in fish and taxonomic criteria available for generic and species determination of amphizoic amoebae are analysed. The limits of morphological and non-morphological approaches in species determination are exemplified by Neoparamoeba, Vannella and Platyamoeba spp., which are the most common amoebae isolated from fish gills, Acanthamoeba and Naegleria spp. isolated from various organs of freshwater fish, and by other unique fish isolates of the genera Nuclearia, Thecamoeba and Filamoeba. Advances in molecular characterisation of SSU rRNA genes and phylogenetic analyses based on their sequences are summarised. Attention is particularly given to specific diagnostic tools for fish-infecting amphizoic amoebae and ways for their further development.

• MeSH
• druhová specificita MeSH
• elektronová mikroskopie MeSH
• fylogeneze MeSH
• Lobosea klasifikace   genetika   ultrastruktura   MeSH
• nemoci ryb diagnóza   parazitologie   MeSH
• protozoální infekce zvířat * MeSH
• protozoální infekce diagnóza   MeSH
• ribozomální DNA genetika   MeSH
• ryby MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• srovnávací studie MeSH
• Názvy látek
• ribozomální DNA MeSH

Nodular gill disease (NGD) is an emerging condition associated with amoeba trophozoites in freshwater salmonid farms. However, unambiguous identification of the pathogens still must be achieved. This study aimed to identify the amoeba species involved in periodic NGD outbreaks in two rainbow trout (Oncorhynchus mykiss) farms in Northeastern Italy. During four episodes (February-April 2023), 88 fish were euthanized, and their gills were evaluated by macroscopic, microscopic and histopathological examination. The macroscopic and microscopic severity of the lesions and the degree of amoebae infestation were scored and statistically evaluated. One gill arch from each animal was put on non-nutrient agar (NNA) Petri dishes for amoeba isolation, cultivation and subsequent identification with SSU rDNA sequencing. Histopathology confirmed moderate to severe lesions consistent with NGD and mild to moderate amoeba infestation. The presence of amoebae was significantly correlated with lesion severity. Light microscopy of cultured amoebae strains and SSU rDNA analysis revealed the presence of a previously characterized amoeba Naegleria sp. strain GERK and several new strains: two strains from Hartmannelidae, three vannelid amoebae from the genus Ripella and cercozoan amoeba Rosculus. Despite the uncertainty in NGD etiopathogenesis and amoebae pathogenic role, identifying known and new amoebae leans towards a possible multi-aetiological origin.

• Klíčová slova
• Oncorhynchus mykiss, Italy, SSU rDNA, amphizoic amoeba, nodular gill disease (NGD), rainbow trout,
• MeSH
• amébiáza * veterinární   parazitologie   MeSH
• Amoeba genetika   izolace a purifikace   klasifikace   MeSH
• Amoebozoa genetika   izolace a purifikace   klasifikace   fyziologie   MeSH
• fylogeneze MeSH
• nemoci ryb * parazitologie   epidemiologie   MeSH
• Oncorhynchus mykiss * parazitologie   MeSH
• vodní hospodářství MeSH
• žábry * parazitologie   patologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Itálie MeSH

The salamander, Ambystoma annulatum, is considered a "species of special concern" in the state of Arkansas, USA, due to its limited geographic range, specialized habitat requirements and low population size. Although metazoan parasites have been documented in this salamander species, neither its native protists nor microbiome have yet been evaluated. This is likely due to the elusive nature and under-sampling of the animal. Here, we initiate the cataloguing of microbial associates with the identification of a new heterlobosean species, Naegleria lustrarea n. sp. (Excavata, Discoba, Heterolobosea), isolated from feces of an adult A. annulatum.

• Klíčová slova
• FLA – free‐living amoeba, Heterolobosea, amphibian, amphizoic, endobiont, eukaryotic gut‐microbiome,
• MeSH
• Ambystoma * parazitologie   MeSH
• feces * parazitologie   MeSH
• fylogeneze MeSH
• Naegleria * izolace a purifikace   klasifikace   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Geografické názvy
• Arkansas MeSH

Parasites, causing little apparent damage in feral fish populations, may become causative agents of diseases of great importance in farmed fish, leading to pathological changes, decrease of fitness or reduction of the market value of fish. Despite considerable progress in fish parasitology in the last decades, major gaps still exist in the knowledge of taxonomy, biology, epizootiology and control of fish parasites, including such 'evergreens' as the ciliate Ichthyophthirius multifiliis, a causative agent of white spot disease, or proliferative kidney disease (PKD), one of the most economically damaging diseases in the rainbow trout industry which causative agent remain enigmatic. Besides long-recognized parasites, other potentially severe pathogens have appeared quite recently such as amphizoic amoebae, causative agents of amoebic gill disease (AGD), the monogenean Gyrodactylus salaris which has destroyed salmon populations in Norway, or sea lice, in particular Lepeophtheirus salmonis that endanger marine salmonids in some areas. Recent spreading of some parasites throughout the world (e.g. the cestode Bothriocephalus acheilognathi) has been facilitated through insufficient veterinary control during import of fish. Control of many important parasitic diseases is still far from being satisfactory and further research is needed. Use of chemotherapy has limitations and new effective, but environmentally safe drugs should be developed. A very promising area of future research seems to be studies on immunity in parasitic infections, use of molecular technology in diagnostics and development of new vaccines against the most pathogenic parasites.

• MeSH
• amébiáza prevence a kontrola   veterinární   MeSH
• Amoeba patogenita   MeSH
• cizopasní červi patogenita   MeSH
• Eukaryota patogenita   MeSH
• helmintózy zvířat prevence a kontrola   MeSH
• Hymenostomatida patogenita   MeSH
• korýši patogenita   MeSH
• losos MeSH
• nemoci ledvin parazitologie   prevence a kontrola   veterinární   MeSH
• nemoci ryb parazitologie   prevence a kontrola   MeSH
• Oncorhynchus mykiss MeSH
• parazitární nemoci u zvířat parazitologie   prevence a kontrola   MeSH
• protozoální infekce zvířat prevence a kontrola   MeSH
• ryby MeSH
• vodní hospodářství * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Amoebae of the genus Acanthamoeba Volkonsky, 1931 are ubiquitous, amphizoic organisms with a cosmopolitan distribution. Pathogenic strains are the causative agents of a difficult to treat disease, granulomatous amoebic encephalitis (GAE), and skin infections in immunocompromised individuals, and of a painful corneal disease--amoebic keratitis (AK) in immunocompetent individuals. The major portals of entry are the nasopharyngeal mucosa, pulmonary parenchyma, skin lesions (GAE, skin infections), eyes in contact lenses wearers with a history of improper contact lens wear and care, or corneal trauma (AK). Symptoms of the diseases are non-specific and variable which alongside with the lack of awareness among health care professionals often hamper early diagnosis. While treatment options for GAE and skin infections are limited and poorly effective, various antifungals and antimicrobials have proved beneficial in AK, although the therapy is often complicated and long.

• MeSH
• Acanthamoeba * MeSH
• akantamébová keratitida diagnóza   terapie   MeSH
• amébiáza diagnóza   terapie   MeSH
• encefalitida diagnóza   parazitologie   terapie   MeSH
• lidé MeSH
• parazitární onemocnění kůže diagnóza   terapie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• přehledy MeSH

Acanthamoeba castellanii is a ubiquitously distributed amoeba that can be found in soil, dust, natural and tap water, air conditioners, hospitals, contact lenses and other environments. It is an amphizoic organism that can cause granulomatous amoebic encephalitis, an infrequent fatal disease of the central nervous system, and amoebic keratitis, a severe corneal infection that can lead to blindness. These diseases are extremely hard to treat; therefore, a more comprehensive understanding of this pathogen's metabolism is essential for revealing potential therapeutic targets. To propagate successfully in human tissues, the parasites must resist the iron depletion caused by nutritional immunity. The aim of our study is to elucidate the mechanisms underlying iron homeostasis in A. castellanii. Using a comparative whole-cell proteomic analysis of cells grown under different degrees of iron availability, we identified the primary proteins involved in Acanthamoeba iron acquisition. Our results suggest a two-step reductive mechanism of iron acquisition by a ferric reductase from the STEAP family and a divalent metal transporter from the NRAMP family. Both proteins are localized to the membranes of acidified digestive vacuoles where endocytosed medium and bacteria are trafficked. The expression levels of these proteins are significantly higher under iron-limited conditions, which allows Acanthamoeba to increase the efficiency of iron uptake despite the observed reduced pinocytosis rate. We propose that excessive iron gained while grown under iron-rich conditions is removed from the cytosol into the vacuoles by an iron transporter homologous to VIT/Ccc1 proteins. Additionally, we identified a novel protein that may participate in iron uptake regulation, the overexpression of which leads to increased iron acquisition.

• Klíčová slova
• Acanthamoeba castellanii, Ferric reductase, Iron metabolism, Iron transporter, Iron uptake, Pinocytosis,
• MeSH
• Acanthamoeba castellanii * MeSH
• homeostáza MeSH
• lidé MeSH
• proteomika MeSH
• voda parazitologie   MeSH
• železo MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• voda MeSH
• železo MeSH