scholarly journals Infection of Slugs with Theronts of the Ciliate Protozoan, Tetrahymena rostrata

2021 ◽  
Vol 9 (9) ◽  
pp. 1970
Author(s):  
Ruth E. Haites ◽  
Anne E. Watt ◽  
Derek A. Russell ◽  
Helen Billman-Jacobe
Keyword(s):  
Ciliated Protozoan ◽  
Deroceras Reticulatum ◽  
Free Living ◽  
Ciliate Protozoan ◽  
Prolonged Starvation ◽  
Facultative Parasite ◽  
Considerable Damage ◽  
Terrestrial Mollusks

Tetrahymena rostrata is a free-living ciliated protozoan and is a facultative parasite of some species of terrestrial mollusks. It is a potential biopesticide of pest slugs, such as the grey field slug, which cause considerable damage to crops. T. rostrata has several developmental forms. Homogeneous preparations of the feeding stage cells (trophonts) and excysted stage cells (theronts) were compared for their ability to infect and kill Deroceras reticulatum slugs. Theronts were more effective and remained viable and infective, even after prolonged starvation.

scholarly journals Identification and Molecular Characterization of Superoxide Dismutases Isolated From A Scuticociliate Parasite: Physiological Role in Oxidative Stress

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Iria Folgueira ◽  
Jesús Lamas ◽  
Ana Paula de Felipe ◽  
Rosa Ana Sueiro ◽  
José Manuel Leiro
Keyword(s):  
Oxidative Stress ◽  
Physiological Role ◽  
Host Immune System ◽  
Farmed Fish ◽  
Free Living ◽  
Antioxidant Defences ◽  
Sod Activity ◽  
Cellular Protection ◽  
Facultative Parasite ◽  
Copper Zinc

Abstract Philasterides dicentrarchi is a free-living microaerophilic scuticociliate that can become a facultative parasite and cause a serious parasitic disease in farmed fish. Both the free-living and parasitic forms of this scuticociliate are exposed to oxidative stress associated with environmental factors and the host immune system. The reactive oxygen species (ROS) generated by the host are neutralized by the ciliate by means of antioxidant defences. In this study we aimed to identify metalloenzymes with superoxide dismutase (SOD) activity capable of inactivating the superoxide anion (•O2−) generated during induction of oxidative stress. P. dicentrarchi possesses the three characteristic types of SOD isoenzymes in eukaryotes: copper/zinc-SOD, manganese-SOD and iron-SOD. The Cu/Zn-SOD isoenzymes comprise three types of homodimeric proteins (CSD1-3) of molecular weight (MW) 34–44 kDa and with very different AA sequences. All Cu/Zn-SODs are sensitive to NaCN, located in the cytosol and in the alveolar sacs, and one of them (CSD2) is extracellular. Mn- and Fe-SOD transcripts encode homodimeric proteins (MSD and FSD, respectively) in their native state: a) MSD (MW 50 kDa) is insensitive to H2O2 and NaN3 and is located in the mitochondria; and b) FSD (MW 60 kDa) is sensitive to H2O2, NaN3 and the polyphenol trans-resveratrol and is located extracellularly. Expression of SOD isoenzymes increases when •O2− is induced by ultraviolet (UV) irradiation, and the increase is proportional to the dose of energy applied, indicating that these enzymes are actively involved in cellular protection against oxidative stress.

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

2008 ◽  
Vol 43 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Marcel D.O. Pinheiro ◽  
Mary E. Power ◽  
Barb J. Butler ◽  
Vivian R. Dayeh ◽  
Robin Slawson ◽  
...  
Keyword(s):  
Cytochalasin B ◽  
Tetrahymena Thermophila ◽  
Biological Mechanisms ◽  
Ciliated Protozoan ◽  
Viral Inactivation ◽  
Free Living ◽  
Bacteriophage Ms2 ◽  
Sybr Gold ◽  
Food Vacuoles ◽  
Formalin Fixed

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.

scholarly journals The protozoan toxin climacostol and its derivatives: Cytotoxicity studies on 10 species of free-living ciliates

Biologia ◽  
2010 ◽  
Vol 65 (4) ◽  
Author(s):  
Federico Buonanno ◽  
Claudio Ortenzi
Keyword(s):  
Common Species ◽  
Aliphatic Chain ◽  
Ciliated Protozoan ◽  
Anticancer Activities ◽  
Free Living ◽  
Parent Molecule ◽  
Cytotoxicity Studies ◽  
Resorcinolic Lipids ◽  
Derivatives Of ◽  
Freshwater Ciliates

AbstractClimacostol (5-(Z)-non-2-enyl-benzene-1,3-diol) is a natural toxin isolated from the freshwater ciliated protozoan Climacostomum virens and belongs to resorcinolic lipids, a group of compounds that show antimicrobial, antiparasitic, and anticancer activities. We investigated the cytotoxic activity of the chemically synthesized toxin and its alkyl and alkynyl derivatives on C. virens and nine other common species of free-living freshwater ciliates. Our results show that the cytotoxic potency of climacostol can be modulated by the substitution of the double bond present in the aliphatic chain of the toxin with a single or a triple one that was previously obtained during the synthesis of the unsaturated and saturated derivatives of the parent molecule. We demonstrated that the cytotoxicity level of the molecules considered in this study appears to be inversely correlated to the unsaturation level of their aliphatic chains, and that the potency of their action is also related to the target organism.

scholarly journals Phasmarhabditis hermaphrodita – a new model to study the genetic evolution of parasitism

Nematology ◽  
2017 ◽  
Vol 19 (4) ◽  
pp. 375-387 ◽  
Author(s):  
Robbie Rae
Keyword(s):  
Molecular Mechanisms ◽  
Phylogenetic Position ◽  
Genomic Comparison ◽  
Free Living ◽  
New Model ◽  
C Elegans ◽  
Genetic Mechanisms ◽  
Facultative Parasite ◽  
Evolutionary Emergence ◽  
Phasmarhabditis Hermaphrodita

The evolutionary genetic mechanisms that are responsible for the transition of free-living nematodes to parasites are unknown and current nematode models used to study this have limitations. The gastropod parasitePhasmarhabditis hermaphroditacould be used as a new model to dissect the molecular mechanisms involved in the evolution of parasitism.Phasmarhabditis hermaphroditais a facultative parasite of slugs and snails that, likeCaenorhabditis elegansandPristionchus pacificus, can also be maintained easily under laboratory conditions.Phasmarhabditis hermaphroditaandPhasmarhabditisspecies are easy to isolate from the wild and have been found around the world. The phylogenetic position ofPhasmarhabditisis ideal for genomic comparison with other clade 9 species such asC. elegansandP. pacificus, as well as mammalian and insect parasites. These attributes could makeP. hermaphroditaan excellent choice of model to study the evolutionary emergence of parasitism.

State-dependent parasitism by a facultative parasite of fruit flies

Parasitology ◽  
2017 ◽  
Vol 144 (11) ◽  
pp. 1468-1475 ◽  
Author(s):  
LIEN T. LUONG ◽  
TAYLOR BROPHY ◽  
EMILY STOLZ ◽  
SOLOMON J. CHAN
Keyword(s):  
Internal State ◽  
Fruit Fly ◽  
Model Systems ◽  
Life History Strategies ◽  
Free Living ◽  
Dependent Plasticity ◽  
Host Condition ◽  
State Dependent ◽  
Facultative Parasite ◽  
Condition State

SUMMARYParasites can evolve phenotypically plastic strategies for transmission such that a single genotype can give rise to a range of phenotypes depending on the environmental condition. State-dependent plasticity in particular can arise from individual differences in the parasite's internal state or the condition of the host. Facultative parasites serve as ideal model systems for investigating state-dependent plasticity because individuals can exhibit two life history strategies (free-living or parasitic) depending on the environment. Here, we experimentally show that the ectoparasitic mite Macrocheles subbadius is more likely to parasitize a fruit fly host if the female mite is mated; furthermore, the propensity to infect increased with the level of starvation experienced by the mite. Host condition also played an important role; hosts infected with moderate mite loads were more likely to gain additional infections in pairwise choice tests than uninfected flies. We also found that mites preferentially infected flies subjected to mechanical injury over uninjured flies. These results suggest that a facultative parasite's propensity to infect a host (i.e. switch from a free-living strategy) depends on both the parasite's internal state and host condition. Parasites often live in highly variable and changing environments, an infection strategy that is plastic is likely to be adaptive.

Distribution and pathogenicity of Tetrahymena limacis in the slug Deroceras reticulatum

Parasitology ◽  
1971 ◽  
Vol 62 (1) ◽  
pp. 125-131 ◽  
Author(s):  
E. H. Michelson
Keyword(s):  
Technical Assistance ◽  
Pathologic Response ◽  
Natural Host ◽  
Morbidity And Mortality ◽  
Tissue Destruction ◽  
Deroceras Reticulatum ◽  
Free Swimming ◽  
Tissue Responses ◽  
Facultative Parasite ◽  
First Time

The distribution of Tetrahymena limacis in its natural host Deroceras reticulatum, and the tissue responses to infection are described. Contrary to previous observations, T. limacis occurred throughout the tissues and organs of its host; the organisms were especially numerous in the kidney, the mantle shield, and in grossly visible papules on the external epithelium. Aspirates from such papules yielded numerous ciliates.T. limacis elicited a considerable pathologic response and appeared to contribute to an increase in morbidity and mortality among slugs. Tissue responses were focal (fibrotic encapsulation of isolated organisms) and diffuse (necrosis, mechanical tissue destruction, and metaplasia). Efforts to establish infection in seven species of molluscs other than D. reticulatum were unsuccessful.An extramolluscan cyst stage of T. limacis is reported for the first time. Both resting and reproductive cysts were observed. Since free-swimming trophozoites of T. limacis are not long lived, the organism is more likely an obligate rather than a facultative parasite of molluscs. Observations also suggest that slugs are infected via the respiratory pore rather than orally.It is a pleasure to acknowledge the aid and counsel given by Dr J. O. Corliss in identifying the ciliate and to Miss Lorin DuBois for technical assistance.

The chemotactic response of Phasmarhabditis hermaphrodita (Nematoda: Rhabditida) to cues of Deroceras reticulatum (Mollusca: Gastropoda)

Nematology ◽  
2006 ◽  
Vol 8 (2) ◽  
pp. 197-200 ◽  
Author(s):  
Michael Wilson ◽  
Jamie Robertson ◽  
Robbie Rae
Keyword(s):  
Entomopathogenic Nematodes ◽  
Parasitic Nematode ◽  
Chemotactic Response ◽  
Deroceras Reticulatum ◽  
Susceptible Host ◽  
Facultative Parasite ◽  
Animal Material ◽  
Volatile Cues ◽  
Growth And Reproduction ◽  
Phasmarhabditis Hermaphrodita

AbstractEntomopathogenic nematodes use a range of cues released by insects to locate hosts but there has been no research on how the slug-parasitic nematode, Phasmarhabditis hermaphrodita, finds potential hosts. We exposed P. hermaphrodita to a range of cues associated with the highly susceptible host Deroceras reticulatum. Cues included foot and mantle mucus and faeces from live D. reticulatum and volatile cues released from this slug. We also compared the attractiveness of live and dead D. reticulatum, and the attractiveness of infected and non-infected D. reticulatum. Phasmarhabditis hermaphrodita responded poorly to volatile cues but was strongly attracted to live D. reticulatum, its faeces and mucus from both the foot and mantle. Phasmarhabditis hermaphrodita was attracted more to dead than live hosts, and was equally attracted to infected and non-infected D. reticulatum. The strong attraction to dead D. reticulatum adds weight to the hypothesis that this nematode is a facultative parasite that is capable of growth and reproduction on decaying plant and animal material present in soil.

scholarly journals Antiprotozoal effects of metal nanoparticles against Ichthyophthirius multifiliis

Parasitology ◽  
2017 ◽  
Vol 144 (13) ◽  
pp. 1802-1810 ◽  
Author(s):  
MONA SALEH ◽  
ABDEL-AZEEM ABDEL-BAKI ◽  
MOHAMED A. DKHIL ◽  
MANSOUR EL-MATBOULI ◽  
SALEH AL-QURAISHY
Keyword(s):  
Silver Nanoparticles ◽  
Zinc Oxide ◽  
Metal Nanoparticles ◽  
Zinc Oxide Nanoparticles ◽  
Control Group ◽  
Oxide Nanoparticles ◽  
Ichthyophthirius Multifiliis ◽  
Ciliated Protozoan ◽  
Free Living

SUMMARYIchthyophthirius multifiliis is a widespread, ciliated protozoan ectoparasite of fish. In the present study, we investigated the effects of metal nanoparticles on the reproduction and infectivity of free-living stages of I. multifiliis. We determined that ~50% of theronts could be killed within 30 min of exposure to either 20 ng mL−1 gold, 10 ng mL−1 silver or 5 ng mL−1 zinc oxide nanoparticles. Silver and zinc oxide nanoparticles at concentration of 10 and 5 ng mL−1 killed 100 and 97% of theronts, respectively and inhibited reproduction of tomonts after 2 h exposure. Gold nanoparticles at 20 ng mL killed 80 and 78% of tomonts and theronts 2 h post exposure, respectively. In vivo exposure studies using rainbow trout (Oncoryhnchus mykiss) demonstrated that theronts, which survived zinc oxide nanoparticles exposure, showed reduced infectivity compared with control theronts. No mortalities were recorded in the fish groups cohabited with theronts exposed to either nanoparticles compared with 100% mortality in the control group. On the basis of the results obtained from this study, metal nanoparticles particularly silver nanoparticles hold the best promise for the development of effective antiprotozoal agents useful in the management of ichthyophthiriosis in aquaculture.

Ultrastructure of neuromuscular relationships in the canine heartworm (dirofilaria immitis)

1986 ◽  
Vol 44 ◽  
pp. 278-279
Author(s):  
W. L. Steffens ◽  
Nancy B. Roberts ◽  
J. M. Bowen
Keyword(s):  
Dirofilaria Immitis ◽  
Domestic Dogs ◽  
Structural Description ◽  
Pharmacological Effects ◽  
Free Living ◽  
Canine Heartworm ◽  
The World ◽  
Synaptic Region ◽  
Muscle Innervation ◽  
Insight Into

The canine heartworm is a common and serious nematode parasite of domestic dogs in many parts of the world. Although nematode neuroanatomy is fairly well documented, the emphasis has been on sensory anatomy and primarily in free-living soil species and ascarids. Lee and Miller reported on the muscular anatomy in the heartworm, but provided little insight into the peripheral nervous system or myoneural relationships. The classical fine-structural description of nematode muscle innervation is Rosenbluth's earlier work in Ascaris. Since the pharmacological effects of some nematacides currently being developed are neuromuscular in nature, a better understanding of heartworm myoneural anatomy, particularly in reference to the synaptic region is warranted.

Lead and lead toxicity in domestic and free living birds

2003 ◽  
Vol 32 (1) ◽  
pp. 3-13 ◽  
Author(s):  
N. De Francisco ◽  
N. De Francisco ◽  
N. De Francisco
Keyword(s):  
Lead Toxicity ◽  
Free Living
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