cDNA cloning and functional characterization of Xenopus laevis DNase γ

The human whipworm, Trichuris trichiura, is estimated to infect 289.6 million people globally. Control of human trichuriasis is a particular challenge, as most anthelmintics have a limited single-dose efficacy, with the striking exception of the narrow-spectrum anthelmintic, oxantel. We recently identified a novel ACR-16-like subunit from the pig whipworm, T. suis which gave rise to a functional acetylcholine receptor (nAChR) preferentially activated by oxantel. However, there is no ion channel described in the mouse model parasite T. muris so far. Here, we have identified the ACR-16-like and ACR-19 subunits from T. muris, and performed the functional characterization of the receptors in Xenopus laevis oocytes using two-electrode voltage-clamp electrophysiology. We found that the ACR-16-like subunit from T. muris formed a homomeric receptor gated by acetylcholine whereas the ACR-19 failed to create a functional channel. The subsequent pharmacological analysis of the Tmu-ACR-16-like receptor revealed that acetylcholine and oxantel were equally potent. The Tmu-ACR-16-like was more responsive to the toxic agonist epibatidine, but insensitive to pyrantel, in contrast to the Tsu-ACR-16-like receptor. These findings confirm that the ACR-16-like nAChR from Trichuris spp. is a preferential drug target for oxantel, and highlights the pharmacological difference between Trichuris species.

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Molecular and functional characterization of Xenopus laevis N-methyl-d-aspartate receptors

Molecular and Cellular Neuroscience ◽

10.1016/j.mcn.2009.06.004 ◽

2009 ◽

Vol 42 (2) ◽

pp. 116-127 ◽

Cited By ~ 5

Author(s):

Carsten Schmidt ◽

Michael Hollmann

Keyword(s):

Xenopus Laevis ◽

Functional Characterization

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Functional characterization of leucine transport induced in Xenopus laevis oocytes injected with mRNA isolated from midguts of lepidopteran larvae (Philosamia cynthia).

Journal of Experimental Biology ◽

10.1242/jeb.198.4.961 ◽

1995 ◽

Vol 198 (4) ◽

pp. 961-966

Author(s):

V F Sacchi ◽

C Perego ◽

S Magagnin

Keyword(s):

Xenopus Laevis ◽

Functional Characterization ◽

Xenopus Laevis Oocytes ◽

Fourfold Increase ◽

Leucine Uptake ◽

Lepidopteran Larvae ◽

Nacl Concentration ◽

Leucine Transport ◽

The Difference

The injection of poly(A)+ mRNA prepared from Philosamia cynthia midgut caused time- and dose-dependent increases of leucine transport in Xenopus laevis oocytes, with an increase in leucine uptake 1.5-3 times that of oocytes injected with water. When the NaCl concentration was reduced from 100 to 5 mmol l-1, the difference between mRNA- and water-injected oocytes was greater and a fourfold increase of L-leucine uptake was measured. D-Leucine (10 mmol l-1) completely inhibited the induced uptake of 0.1 mmol l-1 L-leucine. The newly expressed component of L-leucine uptake increased at alkaline pH and was abolished by incubation for 15 min with 15 mmol l-1 phenylglyoxal. The mean Km values, calculated using Na+ activation curves of leucine uptake, were 23.3 +/- 6.1 mmol l-1 in water-injected oocytes and 0.4 +/- 0.2 mmol l-1 for the newly expressed component of leucine uptake in mRNA-injected oocytes. On the basis of these results, we conclude that the increase of L-leucine uptake in mRNA-injected oocytes was due to the expression of a new transport system, which differs from the endogenous ones and shares many features with that found previously in Philosamia cynthia midgut.

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Cloning and functional characterization of GAD67 upstream regulatory regions in Xenopus laevis

Developmental Biology ◽

10.1016/j.ydbio.2006.04.146 ◽

2006 ◽

Vol 295 (1) ◽

pp. 373

Author(s):

Conor W. Sipe ◽

David Solomon ◽

Margaret S. Saha

Keyword(s):

Xenopus Laevis ◽

Functional Characterization ◽

Regulatory Regions ◽

Upstream Regulatory Regions

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cDNA cloning and functional characterization of flavonol 3-O-glucoside-6″-O-malonyltransferases from flowers of Verbena hybrida and Lamium purpureum

Journal of Molecular Catalysis B Enzymatic ◽

10.1016/j.molcatb.2004.01.005 ◽

2004 ◽

Vol 28 (2-3) ◽

pp. 87-93 ◽

Cited By ~ 12

Author(s):

H Suzuki

Keyword(s):

Cdna Cloning ◽

Functional Characterization

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Functional characterization of high-affinity Na+/dicarboxylate cotransporter found in Xenopus laevis kidney and heart

AJP Cell Physiology ◽

10.1152/ajpcell.00295.2004 ◽

2005 ◽

Vol 289 (5) ◽

pp. C1159-C1168 ◽

Cited By ~ 9

Author(s):

Naomi Oshiro ◽

Ana M. Pajor

Keyword(s):

Xenopus Laevis ◽

Cdna Sequence ◽

Citric Acid Cycle ◽

Functional Characterization ◽

Activation Kinetics ◽

Electrophysiological Properties ◽

High Affinity ◽

The Family ◽

Kidney Liver

The SLC13 gene family includes sodium-coupled transporters for citric acid cycle intermediates and sulfate. The present study describes the sequence and functional characterization of a SLC13 family member from Xenopus laevis, the high-affinity Na+/dicarboxylate cotransporter xNaDC-3. The cDNA sequence of xNaDC-3 codes for a protein of 602 amino acids that is ∼70% identical to the sequences of mammalian NaDC-3 orthologs. The message for xNaDC-3 is found in the kidney, liver, intestine, and heart. The xNaDC-3 has a high affinity for substrate, including a Km for succinate of 4 μM, and it is inhibited by the NaDC-3 test substrates 2,3-dimethylsuccinate and adipate. The transport of succinate by xNaDC-3 is dependent on sodium, with sigmoidal activation kinetics, and lithium can partially substitute for sodium. As with other members of the family, xNaDC-3 is electrogenic and exhibits inward substrate-dependent currents in the presence of sodium. However, other electrophysiological properties of xNaDC-3 are unique and involve large leak currents, possibly mediated by anions, that are activated by binding of sodium or lithium to a single site.

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