Maristentor dinoferus n. gen., n. sp., a giant heterotrich ciliate (Spirotrichea: Heterotrichida) with zooxanthellae, from coral reefs on Guam, Mariana Islands (original) (raw)
Related papers
The Journal of Protozoology, 1987
The morphology and the morphogenesis of the freshwater hypotrich ciliate Onychodromus quadricornutus n. sp. have been investigated using living organisms, protargol impregnation, and scanning electron microscopy. Some preliminary and supplementary results about the morphogenesis of 0. grandis and Laurentiella acuminata are included. The new species is unique among all described hypotrichs in having four dorsal horns, whose function is unknown. In addition, 0. quadricornutus is probably the most voluminous hypotrich ciliate known (2 x 10b-5 x lo6 pm3). Its morphogenetic pattern resembles the oxytrichids 0. grandis and L. acuminata. The strongest apomorphic character, which unites these three species, is probably the multiple fragmentation of the dorsal primordia during morphogenesis. This fragmentation causes the characteristic high number and more or Iess irregular distribution of the dorsal kineties in the non-dividing individuals. YPOTRICHOUS ciliates have been well known for a long H time and were carefully studied by many authors; however, their classification remains controversial to date (5). The new species described is unique among all known hypotrichous ciliates in having horns and presents new data that may contribute to a deeper understanding of systematics and evolution of the family Oxytrichidae in the order Hypotrichida.
Limnology and Oceanography: Methods, 2014
A slide preparation method for seawater samples preserved in acid Lugol's is presented here as an alternative to the traditional Utermöhl settling chamber method for microplankton analysis. This preparation maintains the integrity of fragile cells, such as ciliates, resolves issues associated with the transience of samples prepared in settling chambers, and allows the use of automated image acquisition methods. Samples are filtered onto polycarbonate membranes and analyzed with transmitted light microscopy. The visibility of pore outlines is minimized by using mounting oil (Cargille Series A immersion oil, Certified Refractive Index, n D 25°C 1.5840 ± 0.0002) with a refractive index matching that of the membrane material. We assessed the efficacy of this new method by comparing abundance and biomass estimates for ciliates in settled and filtered samples. Acceptable results were found for the most delicate of samples stored long-term in acid Lugol's. Some cell shrinkage occurred during the filtration and brief drying steps. Therefore, corrections for ciliate length and width measurements in filtered samples were determined to counteract this effect on total cell biovolume. Overall, the method provides a simple and stable alternative to settling chamber analysis for ciliates preserved in acid Lugol's.
The Journal of Protozoology, 1986
Ultrastructural studies of the trophont of the cpizooic loricate peritrich, Circologenophrys ompufla. show that the body conforms to the basic peritrich pattern. The lorica is dome-shaped. and the trophont is joined to it by attachment organelles. A sin& row of bamn aboral kinetosomes is present. In telotroch formation. as cytokinesis proceeds. a band of aboral )rinetosomes develops, running posteroventrally in an arc from the base of the epistomial disc. In one instance, postciliary microtubules were Seen associated with the kinetosomes of the adoral polykinety in a dividing organism. In the fully developed telotroch there arc several distinctive structum. In the midaboral region there is a scopula with numerous bamn kinetosomcs in the epiplasm underlying the pellicle. Surrounding the rim of the aboral surface is a tripartite fringe which overlies the base of the aboral ciliary girdle. The outer layer of this fringe contains regularly spaced electron-dense striations and the middle region contains microfilamenu. The aboral ciliary girdle forms a complete ring. It is composed of diagonal rows of kinetosomes, 8-9 in each row. Striated fiben run between the rows of kinetosomes. They bend at the ends of the rows and continue for some distance below the outer rim of the aboral surface. Running beside each striated fiber i s a band of paracrystalline material. Several distinctive structures are associated with the kinetosoma and striated fibers of the aboral girdle. In the telotroch many of the adoral cilia are absent but the adoral kinetosomes are still present. The possible functions of the specializations of the a b o d surface in settlement of the telotroch, and the relationship between telotroch formation and the molting behavior of the crustacean host arc discussed.
Preservation of marine planktonic ciliates: losses and cell shrinkage during fixation
Marine Ecology Progress Series, 1994
For enumeration of microzooplankton (20-200 pm size fraction), including planktonic ciliates, water samples are usually fixed and preserved, then concentrated by sedimentation in Utermohl chambers and exanlined with an inverted microscope. However, losses of ciliates may occur during fixation and handling, and fixation may shrink cells. Estimates of abundance with several commonly used fixatives were compared In samples from the North Atlantic and subarctic Pacific Oceans and in samples from cultures. Buffered formaldehyde has the advantage that it allows epffluorescence microscopy to be used, but, on average, ciliate counts from the North Atlantic were 56% higher (95 % C1 30 to 82 %) in samples fixed with 10 % acid Lugol's solution than in samples fixed with 2 % formaldehyde. Ciliate counts from the subarctic Pacific were 23 to 49 % higher in samples fixed with 10 or 20 % acid Lugol's solution than in samples fixed with 5 % acid Lugol's solution. Fixation with 10 or 20% acid Lugol's solution results in significantly higher cell counts than fixation with formaldehyde or dilute acid Lugol's solution, but shrinks cells severely and often distorts their morphology. Bouin's solution yields cell counts that are usually similar to those with 10% acid Lugol's solution, but with less shrinkage. No single fixation method is ideal for all purposes; fixative-specific and assemblage-or taxon-specific correction factors are necessary for accurate estimates of cell numbers and cell volumes/biomass. KEY WORDS: Microzooplankton. Ciliates. Oligotrichs-Fixation. Shrinkage-Cell losses. Inverted microscope technique
In this work, we investigate the mechanisms of ciliate infection in the coral Acropora formosa. The results of laboratory experiments showed that healthy corals kept at 24 º C in aquaria and inoculated with cultured ciliates (3-5 cells/ml) remained healthy throughout the experimental period of 120 hours. However, corals kept at 29 º C began to experience tissue loss within three hours of the start of the experiment. There was 40% 5% tissue loss within 24 hours of the start of the experiment. The ciliates engulfed the zooxanthellae cells and eventually degraded them. The infection spreaded and killed coral pieces of 5cm in length in approximately 48 hours. Microscopic observations showed destruction of polyps, coenosarc, and the surface of the coenosteum. As the infection spread and the ciliate abundance increased in the aquaria, all coral fragments were killed. Our results show that ciliates act as opportunists feeding on zooxanthellae from physiologically compromised A. formosa. Our results suggest that temperature stress plays a role in this coral becoming susceptible to ciliate infection.
Limnology and Oceanography, 1998
We examined the ability of the zooxanthellate coral Stylophora pistillata (Esper, 1797) to feed on microhcterotrophs (bacteria and oligotrichous ciliates). The effect of light on the feeding rates was also investigated. Grazing experiments were first conducted by exposing coral colonies to known amounts of "H-thymidine-labeled bacteria and ciliates and measuring the appearance of radioactivity in coral tissues. A method was developed to obtain clean cultures of 3H-labeled ciliates. Results showed that 7% of the labeled bacteria and 90% of the labeled ciliates were ingested after 4-6 h incubation. Corals were then incubated in medium containing different concentrations of unlabeled ciliates (200, 500, 800 cells ml-l), Replicates of each concentration were exposed to one of three light levels (0, 80, 250 µmol m-2 s-l). Coral feeding rate increased with prey density, from 1.40 to 4.10 X 104 ciliates (0.22-0.65 µg C mg protein-l h-l) for 200-800 ciliates ml-1, respectively. However, a plateau was observed after a total ingestion of 4 × 104 ciliates (1.7 µgC mg protein-1). The total number of ciliates ingested, as well as the ingestion rates decreased when the light intensity increased. During dark experiments, the maximal amount of carbon ingested was twice as much as that ingested in light experiments. However, heterotrophic nutrition occurred even if the colonies could satisfy their carbon metabolism via photosynthesis. Zooplankton feeding seems therefore to complement autotrophic nutrition. Under high light, the small amount of microplankton ingested may provide nitrogen, phosphorus, or vitamins to corals, and this food supply may be especially important in tropical waters where inorganic nutrient concentrations are low. Conversely, when light is limiting, predation may also provide most of the energy necessary for coral maintenance.
Limnology and Oceanography, 1998
We examined the ability of the zooxanthellate coral Stylophora pistillata (Esper, 1797) to feed on microhcterotrophs (bacteria and oligotrichous ciliates). The effect of light on the feeding rates was also investigated. Grazing experiments were first conducted by exposing coral colonies to known amounts of "H-thymidine-labeled bacteria and ciliates and measuring the appearance of radioactivity in coral tissues. A method was developed to obtain clean cultures of 3H-labeled ciliates. Results showed that 7% of the labeled bacteria and 90% of the labeled ciliates were ingested after 4-6 h incubation. Corals were then incubated in medium containing different concentrations of unlabeled ciliates (200, 500, 800 cells ml-l), Replicates of each concentration were exposed to one of three light levels (0, 80, 250 µmol m-2 s-l). Coral feeding rate increased with prey density, from 1.40 to 4.10 X 104 ciliates (0.22-0.65 µg C mg protein-l h-l) for 200-800 ciliates ml-1, respectively. However, a plateau was observed after a total ingestion of 4 × 104 ciliates (1.7 µgC mg protein-1). The total number of ciliates ingested, as well as the ingestion rates decreased when the light intensity increased. During dark experiments, the maximal amount of carbon ingested was twice as much as that ingested in light experiments. However, heterotrophic nutrition occurred even if the colonies could satisfy their carbon metabolism via photosynthesis. Zooplankton feeding seems therefore to complement autotrophic nutrition. Under high light, the small amount of microplankton ingested may provide nitrogen, phosphorus, or vitamins to corals, and this food supply may be especially important in tropical waters where inorganic nutrient concentrations are low. Conversely, when light is limiting, predation may also provide most of the energy necessary for coral maintenance.
Acta protozoologica
The living morphology and infraciliature of three heterotrichous ciliates from the north China sea, Condylostentor auriculatus , Condylostoma minutum Bullington, 1940 and C. spatiosum Ozaki and Yagiu in Yagiu, 1944, were investigated using protargol impregnation and in vivo observations. Based on the Qingdao population, an improved diagnosis of the poorly defined Condylostentor Jankowski, 1978 is suggested: free-swimming Stentoridae with deep, prominent vestibular cavity, apical boarder with conspicuous ventral groove; ciliature in Stentor-like pattern, i.e. ventral suture and contrast zone of somatic kineties present; adoral zone almost closed but interrupted on ventral side by a deep cleft, vestibulum kineties on vestibular cavity wall; paroral membrane present. A redescription of Condylostentor auriculatus, the type species, is also supplied. Condylostoma minutum is investigated for the first time using silver impregnation and an improved diagnosis is given based on three populations. New information about some details of the oral apparatus is supplied for a third species, Condylostoma spatiosum. characters can be used for species separation. Furthermore the infraciliature of many nominal species remains unknown thus the identification of these organisms is often difficult (Dragesco
Ciliary basal structures and their distribution in Rhabdopleura compacta (Pterobranchia)
Different epi thelia of the suspension feeding hemichordate Rhabdopleura compacta have been studied ultrastructurally. The epidermis is mainly monociliate, though biciliate cells occur also. CiHa are found in all epithelia, but not every cell bears a cilium. Differences between ciliary basal structures are apparent. In general, four types can be differentiated which are characterized (1) by the absence of any cross-striated rootlet, by the presence of (2) only one vertical rootlet, (3) two vertical rootlets, and (4) a vertical and a horizontal rootlet. Each type of ciliary basal structures is related to certain epitheHa. The distinct distribution of cross-striated ciliary rootlets to different epithelia seems, thus far, to be unique among metazoans.
Effects of fixatives on ciliates as related to cell size
Journal of Plankton Research, 2005
Abundances of ciliate size classes and of phototrophic ciliates were compared between 2% formaldehyde and 1% Lugol's preserved samples collected over 1 year at a coastal Mediterranean site. Large cells and Mesodinuim rubrum were poorly preserved in formaldehyde. A correction factor for ciliate numbers in formaldehyde samples of 1.6 for M. rubrum and of 1.3 for other naked ciliates was found at our study site, where most ciliates were <30 mm equivalent spherical diameter (ESD). Commercially produced Lugol's appears inferior to laboratory prepared solutions.