The Invasive Nature of an Infectious Bacterial Symbiont

Soldo, A. T.; Musil, George; Brickson, S. A.

doi:10.1111/j.1550-7408.1993.tb04879.x

Cited by 10 publications

(4 citation statements)

References 8 publications

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“…Particulates are generally thought to enter the cell via the cytopharyngeal area where food vacuoles are formed. However, a recent electron microscopic study on bacterial symbiont invasion of the ciliate Uronema suggests that the bacteria can enter through the somatic membrane [22]. Invasion or infection may be a special case requiring an infectious agent since phagocytosis at the cell surface membrane is not routinely observed.…”

Section: Discussionmentioning

confidence: 99%

The Kinetics of Fatty Acid Uptake By Paramecium Tetraurelia

Reuter¹,

Prairie

Kaneshiro³

1993

J Eukaryotic Microbiology

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The kinetics of radiolabeled fatty acid uptake by the ciliate Paramecium tetraurelia was examined on a homologous series of saturated, straight chain fatty acids of even carbon numbers. Uptake rates increased with chain length from acetate to palmitate. Saturation kinetics was demonstrated for most fatty acids examined, thus ruling out simple diffusion as the major mechanism for fatty acid transport and implicating carrier-mediated, facilitated transport as the major mechanism. Data from most competitive inhibition experiments were too scattered to determine the number of transporter systems present. Cholesterol uptake also exhibited saturation kinetics and hence other sterols, which can satisfy this nutritional requirement, may also be transported by a carrier-mediated mechanism. The uptake of the essential fatty acid oleate was faster than those observed for the saturated acids and could not be explained by only one transport mechanism. Therefore, fatty acid transport also occurs via other kinetically significant routes.

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Section: Discussionmentioning

confidence: 99%

The Kinetics of Fatty Acid Uptake By Paramecium Tetraurelia

Reuter¹,

Prairie

Kaneshiro³

1993

J Eukaryotic Microbiology

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“…An axenic strain of the scuticociliate Parauronema acutum (ATCC 50189) without infectious symbionts (xenosomes; Soldo et al. ), originally isolated from coastal waters in Florida (Soldo et al. ), was obtained from the American Type Culture Collection, Rockville, Maryland.…”

Section: Methodsmentioning

confidence: 99%

“…An axenic strain of the scuticociliate Parauronema acutum (ATCC 50189) without infectious symbionts (xenosomes; Soldo et al 1993), originally isolated from coastal waters in Florida (Soldo et al 1974), was obtained from the American Type Culture Collection, Rockville, Maryland. The culture was maintained at 20°C in MA medium, but prior to the experiment the ciliates were adapted to sterile 0.22 lm filtered seawater with heat-killed bacteria (HKB) as a food source.…”

Section: Organism and Culture Conditionsmentioning

confidence: 99%

Effects of Temperature and Photorepair Radiation on a Marine Ciliate Exposed to UVB Radiation

Hamsher

Sung

Sanders

2018

J Eukaryotic Microbiology

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The influences of intensity and repeated exposure to ultraviolet-B radiation (UVB), photoreactivating repair radiation (PRR), and temperature on the scuticociliate Parauronema acutum were explored under laboratory conditions. Population growth was negatively affected after exposure to the equivalent of one sunny summer day of ambient UVB, especially in the absence of PRR. Repeated daily exposure to UVB severely compromised ciliate survival. UVB-exposed treatments without PRR recovered slower and reached lower final abundances than treatments receiving PRR. Reducing the daily UVB exposure approximately 25% improved ciliate recovery after exposure. In the single exposure treatments, temperature effects were not consistent, except that growth was slowest for control and treatments at the lowest temperature (15 °C). These data suggest that dark repair and/or photoprotection are present in P. acutum, but photoenzymatic repair was the more effective mechanism in reversing UVB damage. Repeated exposure treatments without PRR had zero or declining growth at all temperatures (15, 20 and 25 °C), as did those with PRR at 15 °C. Significant temperature/dose differences were identified in the repeated exposure treatments; ciliates subjected to the higher UVB intensity with PRR survived only at 25 °C, while ciliate populations under reduced UVB increased at 20 and 25 °C.

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“…These xenosomes have multicopies of their genomes (Soldo, 1986 ). Parauronema is infected by direct penetration of the symbiont through the ciliate's cell membranes, and thereafter only a single xenosome is required to establish a permanent infection (Soldo et al, 1993 ).…”

Section: Types Of Ciliate Symbiosesmentioning

confidence: 99%

Act together—implications of symbioses in aquatic ciliates

Dziallas¹,

Allgaier²,

Monaghan³

et al. 2012

Front. Microbio.

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Mutual interactions in the form of symbioses can increase the fitness of organisms and provide them with the capacity to occupy new ecological niches. The formation of obligate symbioses allows for rapid evolution of new life forms including multitrophic consortia. Microbes are important components of many known endosymbioses and their short generation times and strong potential for genetic exchange may be important drivers of speciation. Hosts provide endo- and ectosymbionts with stable, nutrient-rich environments, and protection from grazers. This is of particular importance in aquatic ecosystems, which are often highly variable, harsh, and nutrient-deficient habitats. It is therefore not surprising that symbioses are widespread in both marine and freshwater environments. Symbioses in aquatic ciliates are good model systems for exploring symbiont-host interactions. Many ciliate species are globally distributed and have been intensively studied in the context of plastid evolution. Their relatively large cell size offers an ideal habitat for numerous microorganisms with different functional traits including commensalism and parasitism. Phagocytosis facilitates the formation of symbiotic relationships, particularly since some ingested microorganisms can escape the digestion. For example, photoautotrophic algae and methanogens represent endosymbionts that greatly extend the biogeochemical functions of their hosts. Consequently, symbiotic relationships between protists and prokaryotes are widespread and often result in new ecological functions of the symbiotic communities. This enables ciliates to thrive under a wide range of environmental conditions including ultraoligotrophic or anoxic habitats. We summarize the current understanding of this exciting research topic to identify the many areas in which knowledge is lacking and to stimulate future research by providing an overview on new methodologies and by formulating a number of emerging questions in this field.

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The Invasive Nature of an Infectious Bacterial Symbiont

Cited by 10 publications

References 8 publications

The Kinetics of Fatty Acid Uptake By Paramecium Tetraurelia

The Kinetics of Fatty Acid Uptake By Paramecium Tetraurelia

Effects of Temperature and Photorepair Radiation on a Marine Ciliate Exposed to UVB Radiation

Act together—implications of symbioses in aquatic ciliates

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