An ultrastructural and molecular study of Hyperamoeba dachnaya, n. sp., and its relationship to the mycetozoan slime moulds

Walker, Gordon; Silberman, Jeffrey D.; Karpov, Sergey A.; Preisfeld, Angelika; Foster, Peter G.; Frolov, Andrei N.; Novozhilov, Yu. K.; Sogin, Mitchell L.

doi:10.1078/0932-4739-00906

Cited by 28 publications

(35 citation statements)

References 35 publications

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“…were present in almost half of the amoebae positive dishcloths. This species, being closely related to the myxogastric slime molds (Walker et al, 2003;Walochnik et al, 2004), has been isolated from human feces, pond water and fecally contaminated soil (Karpov and Mylnikov, 1997;Zaman et al, 1999). This amoeba has three life cycle stages: a flagellated stage, an amoeboid trophozoite and a cyst stage.…”

Section: Discussionmentioning

confidence: 99%

Co-occurrence of free-living protozoa and foodborne pathogens on dishcloths: Implications for food safety

Chavatte

Baré

Lambrecht

et al. 2014

International Journal of Food Microbiology

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In the present study, the occurrence of free-living protozoa (FLP) and foodborne bacterial pathogens on dishcloths was investigated. Dishcloths form a potentially important source of cross-contamination with FLP and foodborne pathogens in food-related environments. First various protocols for recovering and quantifying FLP from dishcloths were assessed. The stomacher technique is recommended to recover flagellates and amoebae from dishcloths. Ciliates, however, were more efficiently recovered using centrifugation. For enumeration of freeliving protozoa on dishcloths, the Most Probable Number method is a convenient method. Enrichment was used to assess FLP diversity on dishcloths (n = 38). FLP were found on 89% of the examined dishcloths; 100% of these tested positive for amoebae, 71% for flagellates and 47% for ciliates. Diversity was dominated by amoebae: vahlkampfiids, vannellids, Acanthamoeba spp., Hyperamoeba sp. and Vermamoeba vermiformis were most common. The ciliate genus Colpoda was especially abundant on dishcloths while heterotrophic nanoflagellates mainly belonged to the genus Bodo, the glissomonads and cercomonads. The total number of FLP in used dishcloths ranged from 10 to 10 4 MPN/cm 2 . Flagellates were the most abundant group, and ciliates the least abundant. Detergent use was identified as a prime determinant of FLP concentrations on used dishcloths. Bacterial load on dishcloths was high, with a mean total of aerobic bacteria of 7.47 log 10 cfu/cm 2 . Escherichia coli was detected in 68% (26/38) of the used dishcloths, with concentrations up to 4 log 10 cfu/cm 2 . Foodborne pathogens including Staphylococcus aureus (19/38), Arcobacter butzleri (5/38) and Salmonella enterica subsp. enterica ser. Halle (1/38) were also present. This study showed for the first time that FLP, including some opportunistic pathogens, are a common and diverse group on dishcloths. Moreover, important foodborne pathogens are also regularly recovered. This simultaneous occurrence makes dishcloths a potential risk factor for cross-contamination and a microbial niche for bacteria-FLP interactions.

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Section: Discussionmentioning

confidence: 99%

Co-occurrence of free-living protozoa and foodborne pathogens on dishcloths: Implications for food safety

Chavatte

Baré

Lambrecht

et al. 2014

International Journal of Food Microbiology

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“…Representatives of these genera have been described with special respect to their ultrastructure by Schuster (1965), Wright et al (1979), Michel et al (2003), Walker et al (2003), and Walochnik et al (2004). To describe life-cycle stages of the organisms mentioned above, different terms have Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The composition of SSU rDNA sequences set (alignment A) prepared to learn phylogeny of strains under study was based on results of our own comparison of light microscopical and ultrastructural features and data obtained from studies of similar organisms (Michel et al 2003, Walker et al 2003, Walochnik et al 2004. After initial analysis, a refined dataset consisting of 13 most closely related sequences and 3 outgroup sequences was assembled (alignment B).…”

Section: Methodsmentioning

confidence: 99%

“…Associated with both kinetosomes were microtubules forming several systems -termed by previous authors as flagellum-cone, rootlet or outer and inner cone-and microfibrillar structures. To designate them, we use for simplicity the terminology based on Karpov and Mylnikov (1997) and Walker et al (2003), i.e., rootlet 1 to 5, R1 to R5, although we realise, that e.g., the outer microtubular cone (R2) is in fact no rootlet.…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

“…The array of these cytoskeletal structures was completed by the posterior parakinetosomal structure (PPKS) (term by Walker et al 2003), consisting of two dense plates holding a network of fine fibres between them, the whole being attached to KS2 (Figs. 13, 26).…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

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Didymium-like myxogastrids (class Mycetozoa) as endocommensals of sea urchins (Sphaerechinus granularis)

Dyková¹,

Lom²,

Dvořáková³

et al. 2007

FOLIA PARASIT

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Abstract. This paper sums up the results of light microscopical, ultrastructural and molecular studies of five strains of amoeboid organisms isolated as endocommensals from coelomic fluid of sea urchins, Sphaerechinus granularis (Lamarck), collected in the Adriatic Sea. The organisms are reported as Didymium-like myxogastrids. Of the life-cycle stages, the attached amoeboids, flagellated trophozoites, cysts and biflagellated swarmers are described. Formation of fruiting bodies was not observed. Although phylogenetic analyses of SSU rDNA sequences indicated a close relationship with Hyperamoeba dachnaya, our sea-urchin strains have not been assigned to the genus Hyperamoeba Alexeieff, 1923. The presence of either one or two flagella reported in phylogenetically closely related organisms and mutually distant phylogenetic positions of strains declared as representatives of the genus Hyperamoeba justify our approach. Data obtained in this study may be useful in future analyses of relationships of the genera Didymium, Hyperamoeba, Physarum and Pseudodidymium as well as in higher-order phylogeny of Myxogastrea.The interest in amoebic diseases of invertebrates recently renewed by outbreaks associated with mass mortalities in American lobsters in Long Island Sound, USA (Mullen et al. 2004(Mullen et al. , 2005, as well as continuing research of Amoebic Gill Disease (AGD) in farmed fish, inspired isolation attempts focused on Paramoeba/ Neoparamoeba spp. as potential agents of infections in invertebrates including sea urchins. Mass mortalities of echinoids attributed to Paramoeba invadens Jones, 1985 infections were reported in the green sea urchin Strongylocentrotus droebachiensis along the Atlantic coast of Nova Scotia, Canada, between 1980 and 1983(Jones 1985.Since the number of amoeboid organisms isolated from invertebrates and stored in culture collections is rather limited, we have characterized several strains isolated from the first set of sea urchins we have sampled thus far. None of the isolated strains could be assigned to Paramoeba/Neoparamoeba species searched for; most of isolated strains were mutually similar and interesting enough to be presented in this study. MATERIALS AND METHODSFive strains of amoeboid organisms presented in the study were isolated from 5 out of 34 sea urchins Sphaerechinus granularis (Lamarck, 1816) screened for the presence of amphizoic amoebae in their coelomic fluid. Strains were denominated as follows: ECH1, ECH14, ECH43, ECH 49, and ECH54. Sea urchins were collected in the Adriatic Sea, in the nearshore area of the Brać Island (Croatia), in June 2005. Sampling of sea urchins was performed using sterile disposable "self-filling" syringes with needles of 23 gauge designed for bleeding in pigs. Modified malt and yeast extract seawater agar (MY75S in the Catalogue of the UK National Culture Collection 2001) was used for isolation attempts as well as for subculturing of primary isolates, strains and clones. The strength of artificial seawater (Sea salts Sigma S9883) was lowered to 30%...

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Archamoebae

Walker

Zadrobílková

Čepička

2017

Handbook of the Protists

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An ultrastructural and molecular study of Hyperamoeba dachnaya, n. sp., and its relationship to the mycetozoan slime moulds

Cited by 28 publications

References 35 publications

Co-occurrence of free-living protozoa and foodborne pathogens on dishcloths: Implications for food safety

Co-occurrence of free-living protozoa and foodborne pathogens on dishcloths: Implications for food safety

Didymium-like myxogastrids (class Mycetozoa) as endocommensals of sea urchins (Sphaerechinus granularis)

Archamoebae

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