Evidence for di-peptide uptake inTetrahymena

Rasmussen, Leif; Zdanowski, Marek K.

doi:10.1007/bf01965958

Cited by 7 publications

(4 citation statements)

References 10 publications

(3 reference statements)

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“…We therefore asked whether potential release from the ectosymbionts, which are attached to the ciliate host on one side only, occurs and leads to uptake by the host. Ciliates can directly take up dissolved organic carbon (Rasmussen and Orias, 1975, Aomine 1978; Rasmussen and Zdanowski, 1980; Aomine 1981; First and Hollibaugh 2009). Some can even grow in axenic, nutrient-rich media without added prey (Soldo and Wagtendonk, 1969; Hanna and Lilly 1974).…”

Section: Resultsmentioning

confidence: 99%

NanoSIMS and tissue autoradiography reveal symbiont carbon fixation and organic carbon transfer to giant ciliate host

et al. 2018

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The giant colonial ciliate Zoothamnium niveum harbors a monolayer of the gammaproteobacteria Cand. Thiobios zoothamnicoli on its outer surface. Cultivation experiments revealed maximal growth and survival under steady flow of high oxygen and low sulfide concentrations. We aimed at directly demonstrating the sulfur-oxidizing, chemoautotrophic nature of the symbionts and at investigating putative carbon transfer from the symbiont to the ciliate host. We performed pulse-chase incubations with 14C- and 13C-labeled bicarbonate under varying environmental conditions. A combination of tissue autoradiography and nanoscale secondary ion mass spectrometry coupled with transmission electron microscopy was used to follow the fate of the radioactive and stable isotopes of carbon, respectively. We show that symbiont cells fix substantial amounts of inorganic carbon in the presence of sulfide, but also (to a lesser degree) in the absence of sulfide by utilizing internally stored sulfur. Isotope labeling patterns point to translocation of organic carbon to the host through both release of these compounds and digestion of symbiont cells. The latter mechanism is also supported by ultracytochemical detection of acid phosphatase in lysosomes and in food vacuoles of ciliate cells. Fluorescence in situ hybridization of freshly collected ciliates revealed that the vast majority of ingested microbial cells were ectosymbionts.

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Section: Resultsmentioning

confidence: 99%

NanoSIMS and tissue autoradiography reveal symbiont carbon fixation and organic carbon transfer to giant ciliate host

et al. 2018

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“…This stimulation is most dramatic at 26" C at pH 7.5 in SB 28 1 cells. When offered glucose, these cells double in less than 10 Cell multiplication of Tetruhymenu thermophilu, strains SB 2 10 and SB 28 1, in the standard medium, Table 1, at 26" and 37" C at pH 5.5 and 7.5. Initial and final cell densities: 1,000 and 400,000 cells per ml, respectively.…”

Section: Resultsmentioning

confidence: 99%

Tetrahymena Thermophila: Growth In Synthetic Nutrient Medium In the Presence and Absence of Glucose

Szablewski¹,

Andreasen²,

Tiedtke³

et al. 1991

The Journal of Protozoology

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This report contains the newest directions for preparation of the synthetic nutrient medium for some Tetrahymena species that do not require lipids. In the standard medium T. thermophila. strains SB 210 and 281, multiply at 37°C with doubling times of around 2 h and at 26°C around 5 h. We have established multiplication rates as functions of variations in the composition of the medium. In media in which all components are present at one‐third of the normal concentrations and only the essential amino acids are included, growth and multiplication become sharply dependent on glucose in strain SB 281. Such media may be used for selection and enrichment of certain specified cell lines.

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“…The present study tells nothing about how the nutrients enter the cells. This question has been addressed in other studies [7,8]. It has been shown that small peptides can pass the cell membrane [8] and that the cells produce proteolytic enzymes [9,10], which probably cleave the long peptides in the medium.…”

mentioning

confidence: 99%

“…This question has been addressed in other studies [7,8]. It has been shown that small peptides can pass the cell membrane [8] and that the cells produce proteolytic enzymes [9,10], which probably cleave the long peptides in the medium. The fact that our data with defined medium are in agreement with those using broth media indicates that we are mainly dealing with uptake across the cell membrane, which follows Michaelis-Menten kinetics.…”

mentioning

confidence: 99%

Division competence in Tetrahymena: Determination of minimum cell volume and rate of nutrient uptake

Andersen

Hellung‐Larsen

1989

J of Cellular Biochemistry

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Cell volume and doubling time have been determined for exponentially growing Tetrahymena pyriformis cells in broth medium with and without glucose and in media made from these media by dilution with water. The cells tolerate media with dry weights from 105 down to 0.06 g/L. In the diluted media the cells have small volumes and the doubling time is increased. When the cell volume increase per time per cell in a given medium is expressed as a function of the cell volume in this same medium, a direct proportionality is found. From this equation the minimum cell volume of division competence (MVDC) can be found. It is 2,100 microns 3 for T. pyriformis at 28 degrees C. The lag period resulting from an upshift of exponentially growing cells from diluted media to more concentrated media is a function of the initial and resulting cell volumes and MVDC. The increase in cell volume per unit of time for a given cell depends on the dry weight of the medium. This parameter can be transformed to mass increase per cell surface area per time, which represents rate of nutrient uptake. When plotted against the dry weight of the media, a Michaelis-Menten-like curve is obtained with two Km values of 3.8 and 0.08 g/L with corresponding Vmax values of 20 and 4 ng/cm2.s. The low Km value (0.08 g/L) indicates that Tetrahymena is able to take up nutrients from highly diluted media. The high value of Vmax (20 ng/cm2.s) increases the ability of growth in more concentrated media.(ABSTRACT TRUNCATED AT 250 WORDS)

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Evidence for di-peptide uptake inTetrahymena

Cited by 7 publications

References 10 publications

NanoSIMS and tissue autoradiography reveal symbiont carbon fixation and organic carbon transfer to giant ciliate host

NanoSIMS and tissue autoradiography reveal symbiont carbon fixation and organic carbon transfer to giant ciliate host

Tetrahymena Thermophila: Growth In Synthetic Nutrient Medium In the Presence and Absence of Glucose

Division competence in Tetrahymena: Determination of minimum cell volume and rate of nutrient uptake

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