Chemokinesis

Houten, Judith Van; Preston, Robin R.

doi:10.1007/978-3-642-73086-3_18

Cited by 7 publications

(13 citation statements)

References 44 publications

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“…Taken together, the results described here argue strongly that parasites are forced to exit the host in response to antibody and provide the molecular basis for previous observations by Cross and Matthews (5) (23)] is controlled through electrophysiological properties of the ciliary/plasma membrane (24). While a mechanism of immunity involving avoidance behavior would tie a problem in immunoparasitology to observations on cell motility dating back almost a century (25), other possibilities could explain this phenomenon as well.…”

Section: Discussionmentioning

confidence: 53%

Surface antigen cross-linking triggers forced exit of a protozoan parasite from its host.

Clark

Lin

Dickerson

1996

Proc. Natl. Acad. Sci. U.S.A.

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We used the common fish pathogen Ichthyophthirius multifliis as a model for studying interactions between parasitic ciliates and their vertebrate hosts. Although highly pathogenic, Ichthyophthirius can elicit a strong protective immune response in fish after exposure to controlled infections. To investigate the mechanisms underlying host resistance, a series of passive immunization experiments were carried out using mouse monoclonal antibodies against a class of surface membrane proteins, known as immobilization antigens (or i-antigens), thought to play a role in the protective response. Such antibodies bind to cilia and immobilize I. multifiliis in vitro. Surprisingly, we found that passive antibody transfer in vivo caused rapid exit of parasites from the host. The effect was highly specific for a given L multifiliis serotype. F(ab)2 subfragments had the same effect as intact antibody, whereas monovalent Fab fragments failed to protect. The activity of Fab could, nevertheless, be restored after subsequent i.p. injection of bivalent goat anti-mouse IgG. Parasites that exit the host had detectable antibody on their surface and appeared viable in all respects. These findings represent a novel instance among protists in which protective immunity (and evasion of the host response) result from an effect of antibody on parasite behavior.

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Section: Discussionmentioning

confidence: 53%

Surface antigen cross-linking triggers forced exit of a protozoan parasite from its host.

Clark

Lin

Dickerson

1996

Proc. Natl. Acad. Sci. U.S.A.

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“…Some of these environmental cues include chemical signals that affect the behavior of the cells, causing them to disperse from, or accumulate in, the vicinity of these compounds. Attractants of Paramecium include folate, lactate, acetate, cyclic AMP, NH 4 ϩ , biotin, and glutamate among others [Van Houten and Preston, 1988;Yang, 1994] (Bell and Van Houten, unpublished results). As products of bacteria, Paramecium's natural food source, these compounds may serve as food cues.…”

Section: Introductionmentioning

confidence: 99%

“…The receptors for organic attractants appear to transduce signals to effector proteins to bring about a subsequent hyperpolarization of the cell [Van Houten and Preston, 1988]. Hyperpolarization in response to at least some organic attractants cannot be accounted for by simple K ϩ or Na ϩ efflux or Clinflux [Preston and Van Houten, 1987], and indirect evidence exists to support the role of a plasma membrane Ca 2ϩ pump as the hyperpolarizing entity in chemoresponse to these attractants [Wright and Van Houten, 1990;Wright et al, 1992Wright et al, , 1993Yano et al, 1996].…”

Section: Introductionmentioning

confidence: 99%

Intracellular pH and chemoresponse to NH4+ inParamecium

Davis

Fiekers

Houten

1998

Cell Motil. Cytoskeleton

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Paramecium are attracted to ammonium chloride solutions relative to sodium chloride control solutions, but little is known about the mechanisms by which attraction is evoked. A known effect of ammonium solutions in other cell types is an alteration of intracellular pH. We show here that intracellular pH is elevated upon initial exposure to 5 mM NH 4 Cl, but appears to decline within 10 minutes, both in wild type cells and in two mutants which do not show sustained attraction to NH 4 Cl using the standard behavioral assay, the T-maze. We also present quantitative values of swimming parameters that underlie the response to NH 4 Cl.

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“…For example, Paramecium tetaurelia utilizes receptor‐mediated signal transduction to accumulate in regions of high folate concentration. Folate serves as an indicator that bacteria, a food source, are nearby (Van Houten 1978, 1988; Van Houten and Prestin 1988). Similarly, the sensitivity of Dictyostelium amoebae to extracellular cAMP (Gerisch 1987) serves as a signal for cell aggregation and differentiation during slug formation.…”

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confidence: 99%

Partial Cloning of Putative G‐Proteins Modulating Mechanotransduction in the Ciliate Stentor

Marino

Sherman

Wood

2001

J Eukaryotic Microbiology

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Signal transduction systems known to utilize G-proteins in higher eukaryotes undoubtedly evolved prior to the development of metazoa. Pharmacological evidence indicates that the ciliates Paramecium, Stentor, and Tetrahymena all utilize signaling systems similar to those found in mammals. However, there has been relatively little direct evidence for the existence of G-proteins in ciliates. Since highly conserved heterotrimeric G-proteins form the basis of receptor-coupled signal transduction systems in a wide variety of metazoa, it is of interest to know if these important signaling molecules were early to evolve and are present and functionally important in a wide variety of unicellular organisms. We have previously shown that mechanotransduction in Stentor is modulated by opiates in a manner that may involve pertussis toxin-sensitive G-proteins. Here we utilize drugs known to interact with G-proteins to further test for the involvement of these important signaling molecules in Stentor mechanotransduction. We present behavioral and electrophysiological data demonstrating that putative G-proteins in Stentor decrease mechanical sensitivity by modulating the mechanotransduction process. In addition, we report the partial cloning of 4 G-protein alpha-subunits from Stentor. We confirm that these clones are of Stentor origin and are transcribed. Furthermore, we employ antisense oligodeoxynucleotide-mediated knockout to demonstrate that these ciliate G-proteins exert a modulatory influence on Stentor behavior, and that a G1/G0-like clone mediates the inhibitory action of beta-endorphin on mechanotransduction.

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Chemokinesis

Cited by 7 publications

References 44 publications

Surface antigen cross-linking triggers forced exit of a protozoan parasite from its host.

Surface antigen cross-linking triggers forced exit of a protozoan parasite from its host.

Intracellular pH and chemoresponse to NH4+ inParamecium

Partial Cloning of Putative G‐Proteins Modulating Mechanotransduction in the Ciliate Stentor

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