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  • Blackwell Publishing Ltd  (7)
  • 2005-2009
  • 2000-2004  (2)
  • 1980-1984  (1)
  • 1975-1979  (4)
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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 23 (1976), S. 0 
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: SYNOPSIS. It was demonstrated with the aid of light and electron microscope studies that Sorites marginalis (Lamarck) harbors zooxanthellae. The hosts were scraped from Thalassia testudinum Konig growing in Key Largo Sound (Florida, U.S.A.) and immediately preserved in appropriate fixatives. Zooxanthellae were distributed unevenly throughout all the chamberlets; only a few symbiotes were found in the embryonic chambers and the inner or outer chambers, but the intermediate chambers were packed with symbiotes. The outer chambers contained many food vacuoles in addition to symbiotes. Some zooxanthellae might have been in the process of degeneration or digestion. The symbiotes were found to have a typical dinoflagellate nucleus, a single large lobate cortical chloroplast with one stalked pyrenoid, an accumulation body, and many starch granules. The nonmotile stage of the zooxanthella was similar, but perhaps not identical, to Symbiodinium microadriaticum Freudenthal from various hosts.The foraminiferan host is heterokaryotic with hundreds of generative (small) nuclei and scores of vegetative (large) nuclei. Most of the generative nuclei were found in the embryonic apparatus and the inner chambers. Most of the vegetative nuclei were found in the inner and outer chambers.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 23 (1976), S. 0 
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: SYNOPSIS. The life cycles of 3 strains of Allogromia laticollaris, a monothalamous foraminiferan, have been studied. Each of the strains had a different, nonclassical, and basically apogamic, life cycle. The Cold Spring Harbor (CSH) strain regularly alternated between 2 agamontic forms: agamont I (uninucleate and diploid) and agamont II (multinucleate and diploid). The complete life cycle took 26 days. Sexual reproduction was rare (0.01%) and autogamous. Small numbers of organisms also underwent budding, binary fission, and cytotomy. The life cycles of the Towd Point (TPA) and Sippewissett (SIP) strains were comparatively abbreviated. Agamont II dominated their typical life cycles, which were completed in 16-18 days. The life cycle of SIP was basically a continuous cycling of the agamont II phase. Approximately 75% of the schizozoites of the TPA strain developed into agamont II. The other 25% alternated between agamont II and agamont I phase.In the CSH strain schizozoites with ∼ 8 (range 5-15) nuclei characterized newly formed agamonts II. More nuclei (∼ 25) were found in the other 2 strains. The nuclei in young agamonts II underwent rapid morphologic changes leading to a “mushroom-like” chromosome appearance and extensive RNA synthesis. Nucleolar material accumulated at the nuclear periphery and eventually was discharged to the cytoplasm. Karyokinesis took place without the breakdown of the nuclear membrane.The single nucleus of young agamont I forms was proportionally quite large. The S1 phase occurred quite early (2-5 days) in this part of the life cycle. RNA in the CSH strain formed a compact, subcortical, coarsely granular ring, while in the TPA it was cortical and differentiated into finely granular matrix with randomly distributed coarse granules. During the G2 phase the nucleus became further enlarged and eventually amoeba-form. Intermediate stages in nuclear breakdown were not found.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 27 (1980), S. 0 
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: SYNOPSIS The time is ripe for protozoan ecologists to begin the general evaluation of the role of food quality in the energy transformations and materials flow in food webs involving protozoa and other small organisms. Current evidence suggests that major pathways of energy flow at any particular time depend upon the matches between prey species and consumers. There are 2 components to food quality related (informational) energy flow: (a) the information present in the molecular constitution of the prey; and (b) the ability of the protozoa to recognize and use it. If the evidence obtained from trophodynamic studies of 2 marine ciliates, Uronema marinum Dujardin and Euplotes vannus Müller indicates a generalized ability of protozoa to regulate catabolic reactions to points which optimize energetic gains from their food, then it may be one of the keys to the evolutionary successes of the group.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 24 (1977), S. 0 
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 48 (2001), S. 0 
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: . Large miliolid foraminifers of the subfamily Soritinae bear symbiotic dinoflagellates morphologically similar to the species of the “Symbiodinium” complex, commonly found in corals and other marine invertebrates. Soritid foraminifers are abundant in coral reefs and it has been proposed that they share their symbionts with other dinoflagellate-bearing reef dwellers. In order to test this hypothesis, we have analysed partial large subunit ribosomal DNA sequences from dinoflagellates symbionts obtained from 28 foraminiferal specimens, and compared them to the corresponding sequences of Symbiodinium-like endosymbionts from various groups of invertebrates. Phylogenetic analysis of our data shows that all soritid symbionts belong to the “Symbiodinium” species complex, within which they form seven different molecular types (Fr1–Fr7). Only one of these types (Fr1) branches within a group of invertebrate symbionts, previously described as type C. The remaining six types form sister groups to coral symbionts previously designed as types B, C, and D. Our data indicate a high genetic diversity and specificity of Symbiodinium-like symbionts in soritids. Except for type C, we have found no evidence for the transmission of symbionts between foraminifers and other symbiont-bearing invertebrates from the same localities. However, exchanges must have occurred frequently between the different species of Soritinae, as suggested by the lack of host specificity and some biogeographical patterns observed in symbiont distribution. Our data suggest that members of the subfamily Soritinae acquired their symbionts at least three times during their history, each acquisition being followed by a rapid diversification and independent radiation of symbionts within the foraminiferal hosts.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 24 (1977), S. 0 
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: SYNOPSIS. Euplotes vannus, a hypotrich ciliate. grows well over broad ranges of temperature and salinity. It requires higher densities of food (〉 1 × 104 cells/ml) for rapid reproduction than do the other herbivores, the foraminiferan Al-logromia laticollaris (〉 1 × 102 cells/ml), and the nematode Chromadorina germanica (∼ 1 × 103 cells/ml), to which it was compared. If food levels were initially very high (∼ 1 × 108 cells/ml) the ciliates reproduced rapidly and consumed the algae faster than it could reproduce. Some balance between the algae and the ciliates was achieved at initial algal concentrations of ∼ 1 × 105 cells/ml. In microcosm experiments at 25 C with equal numbers of C. germanica and A. laticollaris. E. vannus proved to be a very poor competitor; reaching only 20% of control levels when grow with C. germanica and only 13% when cultured with A. laticollaris. It was a better competitor in 2-species microcosms, at lower temperatures, and when its ratio to the other species was initially higher.The experimental evidence suggests that E. vannus is best adapted to being a migrating initial colonizer of fresh algal blooms.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: . A species of Amphidinium bloomed in a mariculture sedimentation pond that was used to grow bivalves near the Gulf of Eilat, Israel. Its overall length averaged 13 μm, the hypocone was 11 μm, and its width was 8μm. It has a ventral ridge. The sulcus begins at the longitudinal flagellar pore and does not project forward in the apex toward the transverse flagellar pore and left margin of the cingulum. The sulcus is a very shallow groove that projects variably about a third of the body length toward the antapex. The cingulum is a deep groove as it circles the cell from the left ventral side to the dorsal side and then becomes very shallow on the right ventral side as it arches posterior toward the longitudinal flagellar pore. Using a modified method for studying dinoflagellate chromosomes in the SEM, we observed 31 chromosomes. The plastid is dorsal and peripheral with 6 ventrally projecting peripheral digital lobes that wrap around the sides of the ventral and posterior nucleus. Amphidinium eilatiensis n. sp. is morphologically closest to Amphidinium carterae and Amphidinium rhynchocephalum, but it does not have the obvious thecal plates or polygonal units described for the former species. Instead, it has a series of spicules, bumps, and ridges on its surface. It differs from A. rhynchocephalum by two morphological characters: surface morphology and gross plastid architecture.The amplified fragments of the rDNA from A. eilatiensis n. sp. isolated from 2 separate sedimentation ponds in Eilat include the 3′-end of the SSU rDNA (about 100 nt), the whole ITS region (ITS1 + 5. 8S + ITS2) and the 5′-end of the LSU rDNA (about 900 nts). The total length of the sequences ranged from 1,460 nt. (A. eilatiensis isolate #1) to 1,461 nts. (A. eilatiensis isolate #2). The latter sequences are identical, the difference in length being due to three insertions. Amphidinium eilatiensis is genetically more closely related to A. carterae than to A. klebsii, with respectively 2. 36% and 6. 93% of sequence divergence.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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