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  • 1
    Electronic Resource
    Electronic Resource
    Mating-Type Polymorphic Variation in Euplotes minuta (Ciliophora: Hypotrichida) (1985)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 32 (1985), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: An investigation was carried out to probe into the mating-type structure of a local population of the marine ciliate, Euplotes minuta. From this population, nine different mating types belonging to a unique set were isolated. The nine type-representative wild stocks analyzed were found to be heterozygous at the mating-type (mat) locus and provided, together with their sexual progeny, a total of 15 pure mating types. In E. minuta, the high-multiple nature of the basic mating system controlled by a series of peck-order alleles at a single locus should be considered a virtual certainty. The relationships among the genetic economies of the similar bottom-dwelling marine ciliates of the genus Euplotes, the E. vannus-crassus-minuta group, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1985.tb03024.x
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  • 2
    Electronic Resource
    Electronic Resource
    IN MEMORIAM: NICOLA RICCI (1947–2000) (2001)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 48 (2001), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.2001.tb00329.x
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  • 3
    Electronic Resource
    Electronic Resource
    Adolescence and the Reversibility of Maturity in Euplotes crassus (1994)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 41 (1994), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . The clonal life history of ciliated protists is characterized by a sequence of phenotypes; sexual immaturity, maturity, and senescence. The distinctiveness of immaturity and maturity has been investigated. Standard assays of the onset of maturity of progeny clones from a cross between stocks EC1 and EC2 of Euplotes crassus demonstrated significant differences among clones and among testers within clones. They also revealed that the first positive test(s) of a progeny subclone were typically followed by at least one negative test. Special protocols were devised to investigate if maturity was reversible at the cellular level. In these experiments, the first mating pair of a progeny subclone was split before the consummation of mating. From these two cells as well as from control progeny and tester cells, subclones were established and every leftover cell was tested for maturity after each transfer. Both standard and split-pair progeny subclones had immature and slow- to-mate cells. The number of fissions before progeny exhibited sexual behavior indistinguishable from the testers was more than twice that to the first mating reaction of a subclone. At the first sign of maturity, progeny lines are a heterogeneous population of cells able and not able to mate, but remarkably, clonal descendants of those able to mate may become unable to mate. The development of maturity is progressive, quantitative and non-monotonic rather than an instantaneous switch.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1994.tb06092.x
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of euplotin C on swimming behavior in Paramecium (2005)
    Oxford, UK : Blackwell Science Inc
    The @journal of eukaryotic microbiology 52 (2005), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The effect of euplotin C—a lipophilic toxic metabolite produced by the protist ciliate Euplotes crassus—on the swimming behavior was studied in a single-celled system represented by the ciliate Paramecium primaurelia. When in P. primaurelia internal Ca2+ concentration coupled to membrane depolarization increases, a reversal in the direction of ciliary beating and consequently in swimming direction occurs. The ciliary reversal is correlated to Ca2+ influx amount. In this study, evidence was given that continuous ciliary reversal (CCR) duration, induced by high external KCl concentrations, is longer in euplotin C-treated cells than in control cells. To test the hypothesis that euplotin C increases CCR duration by modulating a specific subtype of Ca2+ channel, selective Ca2+ channel blockers were used. Blocking L-type channels by nimodipine and verapamil, N- and Q-type channels by Ω-conotoxins, fractions GVIA and MVIIC, significantly reduced the CCR duration evoked by membrane depolarization, suggesting an involvement of these channels in ciliary reversal in Paramecium. The effect of euplotin C on CCR duration persisted when Ω-conotoxin GVIA or Ω-conotoxin MVIIC were applied, conversely, it disappeared when L-type channel blockers were used. The magnitude of the block by nimodipine and verapamil in the presence of euplotin C was comparable with that observed in the absence of euplotin C, suggesting that the Ca2+ channels modulated by euplotin C were dihydropyridine-sensible calcium channels similar to L-type channels found in mammalian cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.2005.05202003_6_12.x
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  • 5
    Electronic Resource
    Electronic Resource
    Non-Mendelian Inheritance of Early Maturity in Euplotes crassus (1990)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 37 (1990), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . This paper reports on a new phenomenon in the ciliated protists: cytoplasmically determined early sexual maturity. Stock MN1 of the marine hypotrich Euplotes crassus matures immediately after conjugation. We analyzed the respective contribuboas of the nucleus and the cytoplasm to the inheritance of this stable condition. A genetic marker, and new methods in E. crassus for cytoplasmic labeling, production of amicronucleates, and induction of selfing were used. Crosses within and among the early mature (EM) variants and late mature (LM) “wild type” lines were done in ovarious combinations. Descendants of EM conjugants continued to be EM, and descendants of LM continued to be LM, regardless of the different experimental approaches used. The results of the crosses clearly show that the clonally stable, variant EM phenotype is transmitted at conjugation in a non-Mendelian manner through the cytoplasmic lineage. The expression of the trait is independent of the micronuclear genome, but the precise site and nature of the hereditary basis is unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1990.tb01250.x
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  • 6
    Electronic Resource
    Electronic Resource
    Mating Types in Aspidisca sp. (Ciliophora, Hypotrichida): a Cluster of Cryptic Species (1987)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 34 (1987), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A mating-type analysis was performed on 78 stocks of the marine hypotrich ciliate, Aspidisca sp., from a sufficient number of diverse geographic locations, some widely separated. Evidence is provided for the existence of a binary mating system in this “morphospecies.” The collected stocks have been challenged by the most rigorous criterion, namely breeding affinity in the laboratory, and have yielded at least four reproductively, not necessarily geographically, isolated groups that are in fact “biological species,” here referred to as “syngens.” Different syngens contain different pairs of mating types. Syngens are morphologically indistinguishable; hence Aspidisca sp. can be considered a conservative taxon comprising a number of “cryptic” or “sibling species.” Information is also presented about the mating behavior and the pattern of nuclear events at conjugation in Aspidisca sp. Search for soluble pheromones of the mating types gave only negative results. Hence, direct contact with potential partners is postulated to play a critical role in preparing individuals to mate. Mating reaction and mating which actually involves cross-fertilization (conjugation, sensu stricto) are completely inhibited by 10 μg/ml cycloheximide, suggesting the necessity of protein synthesis for recognition and union in conjugation of potential partners.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1987.tb03165.x
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  • 7
    Electronic Resource
    Electronic Resource
    Mating by conjugation in two species of the genus Aspidisca (Ciliata, Hypotrichida): an electron microscopic study (1998)
    Springer
    Zoomorphology 118 (1998), S. 1-12 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Behavioral and morphogenetic responses to conjugative interactions of Aspidisca sedigita and A. steini were studied using transmission and scanning electron microscopy. The following changes related to the phenomenon of conjugation have been evidenced. Most of the potential mates show a lifting of the peristomial lip before sticking together in pairs. At the beginning of pairing, mates face each other fusing their lifted peristomial lips. The fusion involves only the mates’ plasma membranes, whereas cortical alveoli are disrupted and unconnected. The left member of the pair (B mate) soon turns through about 180°. Eventually the right ventral side of the rotating B mate overlaps the left dorsal side of the non-rotating one (A mate). Because of this rotation the fusion zone stretches and becomes like a ”tube” rather than being a simple ”door” connecting the mates. In addition to the behavioral differences, the contribution to the ”tube” formation is also different between the two partners of the mating. The B mate supplies the majority of both pellicle and cytoplasm. The dorsal surface of the A mate is partially involved. The morphogenetic pattern during the mating reaction in Aspidisca species has been analyzed and compared with that of members of related genera. It can be related to that of Euplotes species, although differences in the relative timing of the events have been observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050051
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  • 8
    Electronic Resource
    Electronic Resource
    Epoxyfocardin and Its Putative Biogenetic Precursor, Focardin, Bioactive, New-Skeleton Diterpenoids of the Marine Ciliate Euplotes focardii from Antractica (1996)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 79 (1996), S. 439-448 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From the ciliate Euplotes focardii, collected from Ross Sea coastal waters, Antarctica, a new-skeleton diterpenoid, epoxyfocardin, was isolated as a 85:15 mixture of hemiacetals 8a and 8b. The absolute configuration of 8a/8b was determined from Mosher's esters 11a/11b and 12a/12b. Focardin 9a/9b, most likely a biogenetic precursor of 8a/8b, was also isolated as a minor component. Focardin, and particularly epoxyfocardin, proved to be toxic towards representatives of ciliate communities from Antarctic, temperate, tropical, and equatorial environments, constituting the first example of ecologically relevant metabolites from ciliate species that inhabit polar ecosystems.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19960790211
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  • 9
    Electronic Resource
    Electronic Resource
    New Ecotoxicologically and Biogenetically Relevant Terpenes of the tropical green seaweed Caulerpa taxifolia which is invading the Mediterranean (1993)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 76 (1993), S. 855-864 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tropical green seaweed Caulerpa taxifolia (VAHL) C. AGARDH (Caulerpales) which is invading the Mediterranean is shown to contain trace amounts of two further novel terpenes, 7,7-C-didehydro-6-hydroxy-6,7-dihydrocaulerpenyne (= (4S, 6S,1E)-3-[(Z)-acetoxymethylidene]-6-hydroxy-11-methyl-7-methylidenedodeca-1,10-dien-8-yne-1,4-diyl diacetate; 3a) and taxifolione (= 6-methylhept-5-en-3-yn-2-one; 4). The former is the most active of the toxins so far isolated from this seaweed, both as an in vitro inhibitor of the growth of marine bacteria and as a cytotoxic agent toward marine ciliate protists. This suggests a central ecotoxicological role for triacetate 3a as an adjuvant factor in the invasion of the Mediterranean by this seaweed. Moreover, the almost equally toxic 10,11 -epoxycaulerpenyne (2) which is scarcely available from Nature for bioassays can now be obtained by peroxy-acid epoxidation of caulerpenyne (1), along with the 6,7-epoxycaulerpenynes 6b and 6a. The latter are very labile, 6a giving triacetate 3a, suggesting epoxides to be late biogenetic intermediates in C. taxifolia.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19930760209
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  • 10
    Electronic Resource
    Electronic Resource
    Hydrolytic Breakdown of the Euplotins, Highly Strained, Adaptive, Hemiacetal Esters of the Marine Ciliate Euplotes crassus: A Mimic of Degradative Pathways in Nature and a Trick for the Assignment of the Absolute ConfigurationPresented in part by G.G. at ‘XXI Convegno Nazionale della Divisione di Chimica Organica’, Terrasini (Palermo), 28 September-2 October 1993. (1996)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 79 (1996), S. 710-717 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Euplotin C((+)-3), the most abundant of the niche-exploitation terpenoids of the marine ciliate morphospecies Euplotes crassus, was found to undergo degradation in mildly basic H2O/MeOH by initial hydrolysis of the acetate group, followed by, in turn, hydrolytic ring-A and ring-C opening and ring-A reclosure with indiscriminate C(1)/C(15) methanol trapping to give four diastereoisomeric aldehydic hemiacetals 5-8 in similar proportions; 7, as a model for its congeners, proved biologically inactive. From these, the absolute configuration was assigned via Mosher's ester methodology. These processes may be assumed to mimic inactivation of the euplotins in sea water. Degradation of (+)-3 in either stronger base or acidic medium was also examined.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19960790313
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