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Abstract

In total, 8511 amphipods of 12 species caught in Admiralty Bay were examined for the presence of acanthocephalans using them as intermediate hosts. Only 27 specimens of eight species were infected (total prevalence 0.32%). Acanthellae and cystacanths of four species using fishes as either definitive or paratenic hosts were found. Normally, single parasites occurred; in one case two acanthocephalans were present in one specimen of Bovallia gigantea. This host species was the most strongly infected, with the prevalence 3.41%. Six other amphipod species were infected with the prevalence 0.08-0.66%. One of two Jassa ingens examined was also infected. Over 50% of acanthocephalans belonged to one echinorhynchid species maturing in fishes, Aspersentis megarhynchus, which occurred in five host species of four amphipod families, B. gigantea, Gondogeneia antarctica, J. ingens, Hippomedon kergueleni and Orchomenella rotundi-frons. Two polymorphid species maturing in seals, Corynosoma hamanni and C. pseudohamanni, were found in a single host species each, Prostebbingia brevicornis and Cheirimedon femoratus, respectively. Three parasite species mentioned occurred exclusively in sublittoral host species, at the depth 0-30 m. The third polymorphid species, C. bullosum, was the only species occurring in the amphipod, Waldeckia obesa, living in the deeper water (infected specimen was caught at the depth 60 m), but was found also in B. gigantea. Differences between infections of Amphipoda and fishes with echinorhynchids and polymorphids are discussed.
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Abstract

Adult females of a predatory fish, the blackfin icefish, Chaenocephalus aceratus examined at the South Shetland Islands and South Orkney Islands were by several orders of magnitude more infected with Acanthocephala than the males and immature females. Such phenomenon has not been observed in the neritic zone at South Georgia. Cystacanths of Corynosoma hamanni and Corynosoma pseudohamanni were the dominant parasites in Admiralty Bay, whereas Corynosoma bullosum was the dominant in the open sea off the South Shetland Islands and South Georgia, and in the sub-coastal waters off the South Orkney Islands. However, the dominance of C. bullosum was observed in several hosts in Admiralty Bay and the co-dominance of C. bullosum, C. hamanni, and C. pseudohamanni in one mature female in the neritic zone at the South Shetland Islands. Probably, these fish previously lived in the open sea. Cystacanths of Corynosoma arctocephali and Corynosoma shackletoni occurred in the fish in Admiralty Bay and off South Georgia. The former parasite was present also off the South Orkney Islands. One cystacanth of Andracantha baylisi was found off South Georgia. Two echinorhynchids, Aspersentis megarhynchus and Metacanthocephalus dalmori, occurred in the alimentary tracts of the fish caught in Admiralty Bay and one specimen of Echinorhynchus petrotschenkoi off the South Shetland Islands. The highest infection, amounting to 816 acanthocephalans, was found in a mature female in Admiralty Bay. One cystacanth of C. hamanni occurred in a single immature fish caught in the sub-coastal area off Deception Island.
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Abstract

The arbuscules of mycorrhizae develop within apoplastic compartments of the host plant, as they are separated from the cell protoplast by an interfacial matrix continuous with the plant cell wall. Expansins are proteins that allow cell wall loosening and extension. Using fluorescence and electron microscopy we located the NtEXPA5 epitopes recognized by polyclonal antibody anti-NtEXPA5 in mycorrhizal tobacco roots. The expansin protein was localized mainly within the interfacial matrix of intracellular hyphae, arbuscule trunk and main branches. NtEXPA5 proteins were detected neither within the interface of collapsing arbuscule branches nor in non-colonized cortex cells. In plant cell walls, expansin protein was detected only at the penetration point and in the parts of cell walls that adhered firmly to fungal hyphae growing intracellularly. For the first time, NtEXPA5 protein was localized ultrastructurally in hyphae growing intracellularly at the interface of the hypha tip and sites of bending. The novel localization of NtEXPA5 protein suggests that this protein may be involved in the process of arbuscule formation: that is, in promoting apical hyphal growth and arbuscule ramification, as well as in controlling the dynamic of arbuscule mycorrhiza development.
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Abstract

Holoparasitic genera within the family Orobanchaceae are characterized by greatly reduced vegetative organs; therefore, molecular analysis has proved to be a useful tool in solving taxonomic problems in this family. For this purpose, we studied all species of the genera Orobanche and Phelipanche occurring in Central Europe, specifically in Poland, the Czech Republic, Slovakia, and Austria, supplemented by samples mainly from Spain, France, Germany, and Ukraine. They were investigated using nuclear sequences (ITS region) and a plastid trnLtrnF region. The aim of this study was to examine phylogenetic relationships within Orobanche and Phelipanche from Central Europe; we focused on problematic species and aggregates, recent taxonomic changes in these (rank and secondary ranks), and host ranges. The most interesting results concern the exlusion of O. mayeri from O. alsatica aggr. Additionally, following the rules of traditional taxonomy, the correct names and types of some secondary ranks are given and, as a result of this, a new combination below the Phelipanche genus is made (P. sect. Trionychon). The host ranges of the investigated species in Central Europe include 102 species from 12 families, most often from Asteraceae. For this purpose, ca. 400 localities were examined in the field. Moreover, data acquired from the literature and European and Asian herbaria were used.
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