Ciliate Population Research Articles

Live labeling technique reveals contrasting role of crustacean predation on microbial loop in two large shallow lakes

We tested the hypotheses that the ciliate assemblages in moderately eutrophic lake are controlled by the effective crustacean predation, and the high abundances of planktonic ciliates in highly eutrophic and turbid lake are due to insufficient regulation by crustacean zooplankton. A food tracer method coupled with natural assemblage of microciliates labeled with fluorescent microparticles was used to measure the cladoceran and copepod predation rates on planktonic ciliates and to estimate the carbon flow between the ciliate–crustacean trophic links. The results revealed that the microciliates (15–40 μm) were consumed by all dominant cladoceran and copepod species in both the lakes studied, mainly by Chydorus sphaericus and cyclopoid copepods in Lake Vortsjarv, and by Daphnia spp. and Bosmina spp. in Lake Peipsi. The grazing loss in moderately eutrophic Peipsi indicated strong top-down control of ciliates mainly by cladocerans. The extraordinary abundant population of planktonic ciliates having a predominant role in the food web in highly eutrophic and turbid Vortsjarv is explained by the measured low crustacean predation rates on ciliates. The estimated carbon flow from the ciliates to crustaceans suggest that in eutrophic lakes majority of the organic matter channeled via metazooplankton to higher trophic levels may originate from the microbial loop.

Effects of prefermented cereal-derived substrates (ground barley and rye bran) enriched with fungal γ-linolenic acid on rumen fermentation parameters and lipid metabolism in vitro

To increase rumen output of γ-linolenic acid (GLA), we used two cereal-derived substrates, ground barley (GB) and rye bran (RB), enriched with fungal GLA as components of feed rations. We examined their effects on rumen fermentation patterns, lipid metabolism and the ciliated protozoan population in an artificial rumen. Four diets consisting of meadow hay (MH) plus unfermented (GB or RB) or prefermented (GB - TE or RB - TE) cereal-derived substrates were fermented in an artificial rumen with ovine rumen inoculum. The cereal-derived substrates were prefermented with the fungus Thamnidium elegans (TE) by fungal solid-state fermentation. The diets with TE increased the rumen input of dietary GLA (mg day(-1)) from 0 to 21 (GB - TE) or 26 (RB - TE). Both experimental diets increased the rumen output of GLA (P < 0.001). Adverse effects on the ciliate population were observed. Both diets also had an effect on the fatty acids profile. Fermentation patterns were also affected with MH + RB - TE. Cereal-derived substrates enriched with GLA effectively enhanced the output of GLA in artificial rumen. The ability of the fungal strain T. elegans to grow and utilize various agro-industrial substrates might be useful in developing potential new animal diets enriched in GLA.

On the nature of species: insights from Paramecium and other ciliates

The multiple species concepts currently in use by the scientific community (e.g. Morphological, Biological, Phylogenetic) are united in that they all aim to capture the process of divergence between populations. For example, the Biological Species Concept defines a species as a natural group of organisms that is reproductively isolated from other such groups. Here we synthesize nearly a century of research on the ciliate genus Paramecium that highlights the shortcomings of our prevailing notions on the nature of species. In this lineage, there is discordance between morphology, mating behavior, and genetics, features assumed to be correlated, at least after sufficient time has passed, under all species concepts. Intriguingly, epigenetic phenomena are well documented in ciliates where they influence features such as germline/soma differentiation and mating type determination. Consequently, we hypothesize that divergence within ciliate populations is due to a dynamic interaction between genetic and epigenetic factors. The growing list of examples of epigenetic phenomena that potentially impact speciation (i.e. by influencing the dynamics of sex chromosomes, fate of hybrids, zygotic drive and genomic conflicts) suggests that interactions between genetics and epigenetics may also drive divergence in other eukaryotic lineages.

Microfaunal indicators, Ciliophora phylogeny and protozoan population shifts in an intermittently aerated and fed bioreactor

Microfauna community structure was examined in the mixed liquor of a bench-scale bioreactor equipped with an intermittent aeration and feeding system. The reactor was operated under an intermittent aeration of 25min in every 1h and varying feeding conditions (0.264, 0.403 and 0.773kg BOD5/m3d). A total of 14 protozoan and metazoan taxa were identified by microscopic examination. Sessile ciliates, followed by crawling ciliates, were the major protozoan groups under 0.403kg BOD5/m3d organic loading conditions, while sessile ciliate population was remarkably increased under an organic loading of 0.773kg BOD5/m3d. Principal Component Analysis and Pearson correlation coefficient tests were performed in order to reveal relationships between microfauna community and operational parameters. Ciliophora specific-18S rRNA gene clone library was constructed to identify ciliate diversity under 0.773kg BOD5/m3d organic loading conditions. Ciliophora diversity consisted of members of Aspidiscidae, Epistylidae, Opisthonectidae and Vorticellidae, with the majority of the clones being associated with the species Vorticella fusca. At least one novel phylogenetic linkage among Ciliophora was identified. Comparisons made after molecular characterization and microscopic examination of Ciliophora community showed that the estimation of broad ciliate groups is useful for ecological considerations and evaluation of the operational conditions in wastewater treatment plants.

An acute trophic cascade among microorganisms in the tree hole ecosystem following removal of omnivorous mosquito larvae.

Results of two field experiments showed that selective removal of omnivorous mosquito larvae (Aedes triseriatus (Say)) functioning as top predators in the food web of a temperate, tree hole ecosystem resulted rapidly in increased abundance of flagellate and then ciliate populations. Flagellate density increased from <1 per ml to >103 per ml within 4 days of omnivore removal, followed shortly thereafter by an increase in ciliate density from <1 per ml to >102 per ml, after which flagellate density declined, and flagellate and ciliate densities stabilized. Rod-shaped bacteria increased slightly in density after removal of larval mosquitoes, then declined as protist density increased. Cocciform bacteria did not vary in density with these changes, thus the trophic cascade dampened at the remotest trophic level. Concomitant with the increase in protist densities, some bacteria formed elongated filaments >10 μm in length, likely an anti-predation, morphological response stimulated by suddenly intensified grazing as protozoan density rose. Results suggest that feeding by omnivorous mosquito larvae exhibited strong top-down effects on flagellate and ciliate populations, depressing them to below their equilibrium densities and nearly to extinction in tree hole ecosystems.

Effect of yeast cultures supplementation on live weight change, rumen fermentation, ciliate protozoa population, microbial hydrolytic enzymes status and slaughtering performance of growing lamb

Yeast cultures are being exploited as a substitute of antibiotics in animal feeding to promote gut health and performance. This experiment assessed the effect of supplementation of the live yeast cultures on live weight change, rumen fermentation, ciliate protozoa population, microbial hydrolytic enzymes status and slaughtering performance of growing lamb during post weaning phase of growth. Sixty weaner lambs were fed ad libitum a composite feed mixture (CFM) for 91 days in five equal groups. The CFM had roughage to concentrate (R:C) ratio of 25:75. In addition to CFM control lambs were supplemented sterilized culture while other lamb groups received either Kluyveromyces marximanus (NRRL3234; KM), Saccharomyces cerevisiae (NCDC42; SC), Saccharomyces uvarum (ATCC9080; SU) or mixed (all tree cultures in 1:1:1 ratio) culture. The yeast cultures contained 1.5–2.0 × 10 9 cells per ml, which were fed at 1 ml per kg live weight to each lamb of treatment groups. Dry matter intake was similar among control and yeast culture supplemented lambs ranging from 68.4 to 81.2 g/kg W 0.75. However, daily gain was higher (p = 0.002) in SC and mixed yeast culture supplemented lambs. Half carcass weight ranged from 14.2 to 15.1 kg and dressing 52.2 to 53.5% were similar among five lamb groups. Similarly, other carcass traits did not change by yeast supplementation. The SU and mixed culture supplementation declined rumen fluid pH and total volatile fatty acid (TVFA) concentration. Individual yeast cultures increased but mixed yeast culture reduced total ciliates protozoa. Individual cultures increased Entodinomorphs while mixed culture reduced its number in rumen ecosystem. The SU culture increased (p = 0.023) Diplodinomorphs population. Proteases activity was 499, 407, 284 and 144 units higher respectively, in mixed, SC, SU and KM culture supplemented lambs. Cellular activity of α-amylase enzyme was lower in SC, KM and mixed yeast culture lambs. Extra cellular activity of β-glucosidase enzyme was similar (p = 0.581), whereas cellular (p = 0.007) and total activity was higher (p = 0.029) in SU culture lambs. The extra cellular and total activity of xylanase was not different but cellular activity was higher (p = 0.042) in KM lambs. The carboxymethyle cellulase activity was similar among the five animal groups. The SC, SU and mixed culture supplementation improved feed intake (p = 0.722) by 8.0, 13.3 and 18.8% and daily gain (p = 0.002) by 26.6, 11.7 and 18.8% respectively in lambs. The SC culture feeding promoted feed intake and growth by 8 and 26.6% respectively showing the suitability of growth promoting microbial feed additive. The SC culture supplementation in rumen ecosystem also facilitated microbial growth and improved activity of short chain polysaccharides degrading micro-organism. Therefore, SC culture can be used as a growth promoting feed additives in meat animal production.

The Filter-Feeding Ciliates Colpidium striatum and Tetrahymena pyriformis Display Selective Feeding Behaviours in the Presence of Mixed, Equally-Sized, Bacterial Prey

This study examined whether two ciliates could discriminate between equally-sized bacterial prey in mixture and if so, how selectivity might benefit the ciliate population. Live Klebsiella aerogenes, K. ozaenae and Escherichia coli, expressing different coloured fluorescent proteins, were cultured in such a way as to provide populations containing equally-sized cells (to prevent size-selective grazing taking place) and these prey were fed to each ciliate in 50:50 mixtures. Colpidium striatum selected K. aerogenes over K. ozaenae which itself was selected over E. coli. Tetrahymena pyriformis showed no selectivity between K. aerogenes and E. coli but K. aerogenes was selected over K. ozaenae while E. coli was not. This apparent selection of K. aerogenes over K. ozaenae was sustained in ciliate populations with different feeding histories and when K. aerogenes comprised only 20% of the prey mixture, suggesting possible optimal foraging behaviour. The metabolic benefits for selecting K. aerogenes were identified as possibly being an increase in cell biovolume and yield for C. striatum and T. pyriformis, respectively. The mechanism by which these ciliates selected specific bacterial cells in mixture is currently unknown but the use of live fluorescent bacteria, in prey mixtures, offers an exciting avenue for further investigation of selective feeding by protozoa.

Influence of inoculated maize silage and sunflower oil on the in vitro fermentation, ciliate population and fatty acid outputs in the rumen fluid collected from sheep

The effect of maize silage (MS) supplemented with sunflower oil (SO) on the rumen fermentation parameters, growth of ciliate population and fatty acid outputs&lt;I&gt; &lt;/I&gt;was investigated for 72 hours using a batch culture fermentation technique. The rumen fluid from ruminally fistulated sheep was mixed with McDougall’s buffer (1:1) and added (35 ml) to fermentation bottles containing 1.5 g (0.38 g of DM) of MS with or without SO (30 g/kg of DM). Four types of MS were used: uninoculated (MS) or inoculated with &lt;I&gt;Lactobacillus plantarum&lt;/I&gt; CCM 4000 (MS+LP), &lt;I&gt;Lactobacillus fermentum&lt;/I&gt; LF2 (MS+LF) or &lt;I&gt;Enterococcus faecium &lt;/I&gt;CCM 4231 (MS+EF) in simultaneous incubations at 39 ± 0.5°C for 72 h &lt;I&gt;in vitro&lt;/I&gt;. Total gas production was decreased by SO (by 16–17%) in MS and all inoculated MS. Methane production was not significantly influenced by SO. The concentration of total volatile fatty acids, molar proportions of acetate, propionate and &lt;I&gt;n&lt;/I&gt;-butyrate were influenced by SO (&lt;I&gt;P&amp;nbsp;&amp;lt;&amp;nbsp;&lt;/I&gt;0.05; &lt;I&gt;P &amp;lt; &lt;/I&gt;0.01; &lt;I&gt;P &amp;lt; &lt;/I&gt;0.001). SO had no significant effect on the total ciliate number and growth of the examined ciliate species &lt;I&gt;Entodinium &lt;/I&gt;spp., &lt;I&gt;Dasytricha ruminantium&lt;/I&gt;, &lt;I&gt;Polyplastron multivesiculatum&lt;/I&gt;,&lt;I&gt; Enoploplastron triloricatum&lt;/I&gt; and&lt;I&gt; Diplodinium denticulatum&lt;/I&gt;. The number of &lt;I&gt;Dasytricha ruminantium&lt;/I&gt; with MS+LP was higher (&lt;I&gt;P &amp;lt; &lt;/I&gt;0.01) as compared to MS. Outputs of &lt;I&gt;trans&lt;/I&gt; vaccenic acid (TVA), linoleic acid, conjugated linoleic acid (CLA) and α-linolenic acid were influenced by SO (&lt;I&gt;P&amp;nbsp;&amp;lt;&amp;nbsp;&lt;/I&gt;0.05;&lt;I&gt; P &amp;lt; &lt;/I&gt;0.01; &lt;I&gt;P &amp;lt; &lt;/I&gt;0.001). However, the output of CLA was increased only in MS+LF (&lt;I&gt;P &amp;lt;&lt;/I&gt; 0.001). It can be concluded that the supplementation of sunflower oil into maize silage is not effective as dietary antiprotozoal agents in a short-time interval, but it might positively affect the rumen bacterial population and activities. Sunflower oil with inoculated and uninoculated maize silage could be effective for an increase of TVA in the rumen fluid of sheep.&amp;nbsp; &amp;nbsp;

Influence of palm fatty acid distillate on rumen degradability and protozoa population in buffaloes

Oil and fat as energy sources at low cost are relevant in ruminant nutrition. The aim of this study was to evaluate the effects of palm fatty acid distillate (PFAD) on the degradability and ciliate protozoa population in buffalo. Four rumen fistulated buffaloes were fed a basal diet in a Latin square (4×4) design trial. Treatments were designed with four of different levels of PFAD added directly into the rumen: 0; 200; 420 and 500 g/animal/d. High levels of PFAD (420 and 500 g/d) promoted higher degradation of the soluble fraction and lower in potentially degradable fraction of dry matter (DM) and neutral detergent fibre (NDF) with lower values of potential and effective degradability in two evaluated grasses, bermudagrass and brachiariagrass. Significant decreases in the total number of protozoa/mL of rumen content, Entodinium and ciliates belonging to subfamily Diplodiniinae were observed at higher level of PFDA addition in the rumen. Also, Epidinium and Holotrich ciliates disappeared from the rumen. Significant correlations were observed of the ciliate concentration and composition as a function of dietary lipids content. Entodinium composition increased from 68.0% to 99.6% and Diplodiniinae reduced from 30.4% to 0.4% with increasing PFAD level indicating higher fat toxicity effect on the Diplodiniinae ciliates than Entodinium species and direct action of the larger ciliates on the fibre degradation.

Grazing impact of natural populations of ciliates and dinoflagellates in a river-influenced continental shelf

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 56:93-108 (2009) - DOI: https://doi.org/10.3354/ame01319 Grazing impact of natural populations of ciliates and dinoflagellates in a river-influenced continental shelf Cristian A. Vargas*, Rodrigo A. Martínez Aquatic Research Unit, Environmental Sciences Center EULA Chile, Universidad de Concepción, PO Box 160-C, Concepción, Chile *Email: crvargas@udec.cl ABSTRACT: The abundance and biomass of ciliates and dinoflagellates in a nearshore area affected by freshwater runoff and coastal upwelling events were assessed during 7 campaigns distributed over winter and spring months between 2006 and 2008 in the Itata river plume and off Coliumo Bay in Central Chile (~36°S). Grazing rates were also established for both aloricate ciliate and naked dinoflagellate populations using data on instantaneous food vacuole content via the uptake of fluorescently labelled algae (FLA). Both dinoflagellates and ciliates were more abundant in the less saline waters of the river plume. The dominant micrograzers on FLA were the dinoflagellates Gyrodinium spp. and Gymnodinium spp. and the ciliates Strombidium spp. Ingestion by naked dinoflagellates ranged from 0.06 to 0.14 prey d–1, whereas aloricate ciliates ingested between 20 and 35 prey d–1. Maximum carbon ingestion of naked dinoflagellates occurred during spring, whereas it peaked both in winter and in spring in aloricate ciliates. The highest grazing impact of ciliates on nanoplankton (~99% of primary production d–1) occurred during winter within the river plume. The higher abundance of small potential prey, as well as the resulting higher grazing impact of microzooplankton during winter in the river plume area, suggest an adequate environment for protozoan growth. KEY WORDS: Naked dinoflagellates · Aloricate ciliates · Grazing impact · Microbial food web · River plume Full text in pdf format PreviousCite this article as: Vargas CA, Martínez RA (2009) Grazing impact of natural populations of ciliates and dinoflagellates in a river-influenced continental shelf. Aquat Microb Ecol 56:93-108. https://doi.org/10.3354/ame01319 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 56, No. 1. Online publication date: July 10, 2009 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2009 Inter-Research.

Effect of humic acid on fermentation and ciliate protozoan population in rumen fluid of sheep in vitro

AbstractBACKGROUND: Humic acid (HA) as a product of decomposition of animal and plant tissue is used in animal production as a feed supplement, antimicrobial product and growth stimulator. The objective of the present in vitro study was to investigate the effects of dietary humic acid as a commercial Humacid 60 Basic (H60B) feed additive preparation on rumen fermentation and the ciliate protozoan population in the rumen fluid of sheep using a high fibre (HF) and high concentrate (HC) diet in batch cultures and artificial rumen (RUSITEC).RESULTS: Production of total volatile fatty acids (VFAs) was significantly decreased (P &lt; 0.001) for batch cultures by the HF‐H60B diet. The HF‐H60B diet decreased ammonia N in RUSITEC (P &lt; 0.001). An increase in the population of Enoploplastron triloricatum, Isotricha spp. and Ophryoscolex c. tricoronatus with the HF‐H60B diet and Diploplastron affine with the HC‐H60B was observed. The H60B did not affect the total ciliate population and Entodinium spp.CONCLUSION: It can be concluded that dietary humic acid preparations are not effective as dietary antiprotozoal agents. Humic acid might enhance microbial growth and energy efficiency in doses up to 10 g kg−1 DM of diet. Copyright © 2009 Society of Chemical Industry

Contribution of auto- and heterotrophic protozoa to the diet of copepods in the Ulleung Basin, East Sea/Japan Sea

We estimated the ingestion rates and prey selectivity of two calanoid copepods, Calanus sinicus and Neocalanus plumchrus, on auto- and heterotrophic protozoa in the Ulleung Basin in the East Sea/Japan Sea. Both copepod species preferentially ingested auto- and heterotrophic protozoa. The heterotrophic protozoa comprised between 42.9 and 86.7% of the total carbon ration ingested by the copepods, although they comprised on average 21.5% of the total available prey carbon. In particular, ciliates comprised the major dietary component for the copepods in the study area. The copepod consumption of ciliates was on average 38.2% of the total daily carbon ration of auto-and heterotrophic protozoa. Auto- and heterotrophic protozoa in the 20―50 μm size were the fraction that was most actively consumed by copepods and they comprised on average 45.1% of the total carbon ration ingested. In all experiments, the copepods selected the ciliate and heterotrophic dinoflagellate (HDF) groups over the other protozoa. Our results indicate that the copepod feeding regime was influenced by the composition and size of the potential food and that, in this study area, feeding behavior of copepods may control the populations of ciliates and HDFs that are larger than 10 μm in size. Thus, the selective feeding patterns and higher grazing pressure of copepods on heterotrophic protozoa, compared with autotrophic protozoa, indicate a trophic coupling between copepods and the microbial food web in the Ulleung Basin.

“Candidatus Cryptoprodotis polytropus,” A Novel Rickettsia‐Like Organism in the Ciliated Protist Pseudomicrothorax dubius (Ciliophora, Nassophorea)

Rickettsia-like organisms (RLO) are obligate, often highly fastidious, intracellular bacterial parasites associated with a variety of vertebrate and invertebrate hosts. Despite their importance as causative agents of severe mortality outbreaks in farmed aquatic species, little is known about their life cycle and their host range. The present work reports the characterization of "Candidatus Cryptoprodotis polytropus," a novel Rickettsia-like bacterium associated with the common ciliate species Pseudomicrothorax dubius by means of the "Full-Cycle rRNA Approach" and ultrastructural observations. The morphological description by in vivo and scanning electron microscopy and the 18S rRNA gene sequence of the host species is provided as well. Phylogenetic analysis based on the 16S rRNA gene supports the inclusion of "Candidatus Cryptoprodotis polytropus" within the family Rickettsiaceae (cl. Alphaproteobacteria) together with the genera Rickettsia and Orientia. Observations on natural ciliate populations account for the occasional nature of this likely parasitic association. The presence of a previously unknown RLO in ciliates sheds a new light on the possible role of protists as transient hosts, vectors or natural reservoir for some economically important pathogens.

The Study of Diversity of Ciliate Protozoa in Ghizel Sheep Fed in Pasture and Nourished by Dried Grape by-Product

Problem statement: Ciliate protozoa are one of the normal microorganisms that found in rumen of both domestic and wild ruminants. Several factors seem to influence the concentration and composition of the protozoal fauna in the rumen. The aim of the present study was to determine the rumen ciliates protozoa diversity in Ghizel sheep of East Azerbaijan province and evaluate effects of alfalfa replacement by multiple level of dried grape by-product (0, 15, 30 and 45% of diet) on ciliate protozoa population. Approach: In the first experiment, samples of rumen fluids were collected from 16 mature sheep. Selected sheep were belonged to 4 pure herds of Ghizel sheep in east Azerbaijan province. In the second experiment, sixteen mature Ghizel wether sheep of live weight 34 kg (±1.5) were used. Data obtained from study was subjected to ANOVA as a completely randomized design with 4 replicates by the GLM procedure and treatment means were compared by the Duncan test. Results: In experiment 1, different geographical locations affect total number of rumen ciliated protozoa (p<0.05), Entodinium spp. and Dasytricha spp. In experiment 2, the concentrations of Entodinium spp., Diplodinium spp., Holotricha spp. and Opharyoscolex species were higher when 15% dried grape by-product (DGB) was included in the diet. With increasing DGB in diets the number of Epidinium spp. and Euodiplodinium spp. reduced in treatments 2 (15% of diet replaced by DGB) and 3 (30% of diet replaced by DGB) (p<0.05). Conclusion: The different geographical locations affected total number of rumen ciliated protozoa, Entodinium spp. and Dasytrisha spp. The concentration of Diplodinium was observed to increase when sheep were fed with dried grape by-product.

Protozoários ciliados do rúmen de bovinos e bubalinos alimentados com dietas suplementadas com monensina ou própolis

O objetivo deste trabalho foi avaliar o efeito de dietas suplementadas com monensina ou produtos à base de própolis, nas populações de protozoários ciliados no rúmen de bovinos (Bos taurus) e bubalinos (Bubalus bubalis). Quatro bovinos da raça Holandesa e quatro búfalos da raça Murrah adultos, fistulados no rúmen, foram distribuídos em delineamento quadrado latino (4x4). A dieta constituiu-se de 50% de silagem de milho e 50% de concentrado à base de milho em grãos e farelo de soja, com adição de monensina sódica ou aditivo à base de própolis LLOSA2 ou LLOSC1. As amostras do conteúdo ruminal foram coletadas duas horas após a alimentação. O gênero Entodinium foi o mais representativo em todos os tratamentos, para ambas as raças de ruminantes. Em búfalos, foi observado o efeito redutor do tratamento LLOSC1 nas populações do gênero Entodinium, além do efeito redutor dos tratamentos monensina e LLOSA2 sobre os gêneros da subfamília Diplodiniinae. A média de ciliados foi maior em bubalinos (56x10(4) mL-1) do que em bovinos (26x10(4) mL-1). Houve aumento do pH ruminal dos bovinos no tratamento com monensina. O extrato de própolis LLOSC1 reduziu os ciliados do rúmen em bubalinos.

A mechanism of transmission and factors affecting coral susceptibility to Halofolliculina sp. infection

Anecdotal evidence collected since 2004 suggests that infections caused by ciliates in the genus Halofolliculina may be related to coral mortality in more than 25 scleractinian species in the Caribbean. However, the relationship between the presence of ciliates and coral mortality has not yet been firmly established. Field and laboratory manipulations were used to test if ciliate infections harm corals, if ciliates are able to infect healthy colonies, and if coral susceptibility to ciliate infection depends on temperature, depth, distance to an infected colony, and the presence of injuries. Ciliate infections were always characterized by a visually detectable front of ciliates located on recently exposed coral skeletons. These infections altered the normal structure of the colony by causing tissue mortality (0.8 ± 0.95 cm month−1, mean ± SD) and by delaying or preventing recovery from injuries. Under laboratory conditions, ciliates transmitted directly and horizontally from infected to healthy hosts, and coral susceptibility to ciliate infections increased with the presence of injuries. After invasion, the ciliate population grew, rapidly and after 8 d, produced tissue mortality on 32% of newly infected hosts. Thus, our results support the existence of a new Caribbean coral syndrome that is associated with tissue mortality, is infectious, and transmits directly and horizontally. Even though the role of ciliates in the development of lesions on coral tissues remains unclear, their presence is by far the most conspicuous sign of this syndrome; thus, we propose to name this condition Caribbean ciliate infection (CCI).

Inactivation of the Bacteriophage MS2 by the Ciliated Protozoan, Tetrahymena thermophila

Abstract Because the range of biological mechanisms responsible for the inactivation of viruses in man-made and natural water systems is poorly understood, the involvement of the free-living ciliated protozoan, Tetrahymena thermophila, in viral inactivation was investigated. The ciliate was found to remove the bacteriophage MS2 when the phage and ciliate were co-incubated in a simple salt solution. MS2 was enumerated as plaque forming units (pfus). MS2 removal was achieved only by living and not formalin-fixed ciliates, and was blocked by treatments that impaired the formation of food vacuoles. These treatments were cytochalasin B and low temperature. When fluorescently labelled with SYBR gold prior to co-incubation, MS2 were seen inside Tetrahymena within vesicles that had the shape and size of food vacuoles. The number of pfus associated with Tetrahymena was low. This suggests that the engulfment of the phage into food vacuoles led to the inactivation of MS2, which is frequently used as a surrogate for poliovirus in environmental microbiology. In the future, a broader understanding of the capacity of ciliates to inactivate viruses could lead to methods for improving water quality through the manipulation of ciliate populations and activities.

Fatty acid profiles of rumen fluid from sheep fed diets supplemented with various oils and effect on the rumen ciliate population

The profile of trans-fatty acids and the protozoan population were evaluated in four ruminally fistulated sheep fed a diet with meadow hay: barley grain ratio (80:20%) plus sunflower oil (SO), rapeseed oil (RO) or linseed oil (LO) (5% wt/wt). The concentrate was daily mixed with individual oils and offered at 07.00 h. A 4 × 4 Latin square with 4-week periods was used. The concentration of trans-vaccenic acid (TVA) was the highest 4 h after feeding (36.1 g/100 g FA with SO; 34.5 g/100 g FA with RO) and then decreased with the time after feeding (&lt;i&gt;P&lt;/i&gt; &lt; 0.05). The concentration of &lt;i&gt; cis9, trans&lt;/i&gt;11 conjugated linoleic acid (c9,t11-CLA) with RO increased from 3.23 g/100 g FA (2 h after feeding) to 4.67 g/100 g FA (4 h after feeding). The concentration of c9,t11-CLA with SO increased from 2.09 g/100 g FA (2 h after feeding) to 2.31 g/100 g FA (4 h after feeding). The concentration of c9,t11-CLA with LO was the highest 4 h after feeding (2.07 g/100 g FA). Overall effects of the oil supplements and time after feeding on short-chain fatty acids (SCFA), medium-chain fatty acids (MCFA) and long-chain fatty acids (LCFA) in the rumen fluid were evident. A strong interaction of oil supplements and time after feeding was detected in the concentration of UFA and SFA (&lt;i&gt;P&lt;/i&gt; &lt; 0.001). A significant effect of LO on the rumen ciliate population was observed; the total protozoan concentration and the number of &lt;i&gt;Entodinium&lt;/i&gt; spp. were decreased as well as &lt;i&gt;Dasytricha ruminantium, Isotricha&lt;/i&gt; spp., &lt;i&gt;Polyplastron multivesiculatum, Ophryoscolex c. tricoronatus&lt;/i&gt; and&lt;i&gt; Eremoplastron dilobum&lt;/i&gt;.

The host species affects the microbial community in the goat rumen

This study was carried out to determine whether bacterial and ciliate populations in goat rumen vary significantly between different goat species living in the same environment. Bacterial and ciliate communities in the rumen of three goat species were analysed at the molecular level using denaturing gradient gel electrophoresis. The microbial community varied considerably among goats living in the same environment. Interspecies variation in the bacterial population was noticeably greater than intraspecies variation. In contrast, there was considerable variation in the ciliate population among goats within the same species, and intraspecies similarities were no greater than those observed across species. Because environmental factors and diets were identical for all goats, differences in bacterial populations reflect species-specific differences in rumen microbes. Factors related to the host species have an important effect on determining the bacterial composition in the goat rumen.

Can the surface immobilization antigens of Philasterides dicentrarchi (Ciliophora: Scuticociliatida) be used as target antigens to develop vaccines in cultured fish?

In order to test whether immobilization antigens (i-antigens) of Philasterides dicentrarchi could be suitable antigenic targets against scuticociliatosis, polyclonal olive flounder ( Paralichthys olivaceus) sera were raised against P. dicentrarchi by immunization with lysates of ciliates grown using chinook salmon epithelial (CHSE) cells, and the ability of the immune sera to kill the ciliates via classical complement pathway was analyzed in relation to agglutination activity. The immune sera showed clear agglutination activity against the CHSE-cultured ciliates. However, the agglutinated ciliates were not killed but escaped from the agglutinated mass within a few hours. Ciliates isolated from fish artificially infected with the same population of CHSE-cultured ciliates were not agglutinated by the immune sera even at the lowest dilution. In antibody-dependent complement-mediated killing (ADCK), the immune sera completely killed the CHSE-cultured ciliates at relatively higher serum dilutions (showing low or no agglutination activity). However, CHSE-cultured ciliates were not killed completely at lower immune serum dilutions (showing high agglutination activity). In contrast to CHSE-cultured ciliates, the ciliates isolated from infected fish were killed at lower dilutions of the immune sera in spite of no agglutination response. Considering the presence of various i-antigen types, ability to change i-antigen type in response to corresponding antibody, and relatively low ADCK activity at high agglutination titer, i-antigens of P. dicentrarchi may not be good targets for subunit vaccine development. To develop subunit vaccines against scuticociliatosis, other surface antigens expressed constitutively or expressed specifically under the infection state for survival of the ciliates in the host fish might be more favorable to elicit protective antibodies than the surface i-antigens.