Disease relevance of Planarians

• Toxicity of selenium (Na2SeO3) and mercury (HgCl2) on the planarian Dugesia gonocephala [1].
• Cocarcinogenesis between cadmium and Aroclor 1254 in planarians is enhanced by inhibition of glutathione synthesis [2].

High impact information on Planarians

• Here we report the identification and characterization of nou-darake (ndk), a gene encoding a fibroblast growth factor receptor (FGFR)-like molecule specifically expressed in the head region of the planarian Dugesia japonica [3].
• Searching for the prototypic eye genetic network: Sine oculis is essential for eye regeneration in planarians [4].
• To identify potential pattern-control genes in planarian regeneration, we have isolated two homeobox-containing genes, Dth-1 and Dth-2 [Dugesia (Girardia) tigrina homeobox], by using degenerate oligonucleotides corresponding to the most conserved amino acid sequence from helix-3 of the homeodomain [5].
• In this study, we identified a homologue of the Drosophila PUF gene Pumilio (DjPum) in the planarian Dugesia japonica, with an expression pattern preferentially restricted to neoblasts [6].
• Inactivation of both Pax6A and Pax6B by RNA-mediated gene interference (RNAi) inhibits neither eye regeneration nor eye maintenance, suggesting that the genetic network that controls this process is not triggered by Pax6 in planarians [7].

Chemical compound and disease context of Planarians

• Neurobehavioral toxicity of cadmium sulfate to the planarian Dugesia dorotocephala [8].
• Comparative acute toxicity of DDT metabolites among American and European species of planarians [9].

Biological context of Planarians

• The finding that freshwater planarians can regenerate eyes without the contribution of Pax6 suggests that alternative combinations of regulatory elements may control the morphogenesis of the prototypic planarian eye [10].
• Here we show that planarians are, in fact, capable of incorporating the thymidine analogue bromodeoxyuridine (BrdU), allowing neoblasts to be labeled specifically during the S phase of the cell cycle [11].
• Redundant primers matching well-conserved sequences within vertebrate and invertebrate POU genes were used in the PRC (polymerase chain reaction) to detect three different POU-domain-containing genes within the genome of the flatworm, Dugesia tigrina [12].
• Circadian rhythm of serotonin levels in planarians [13].

Anatomical context of Planarians

• Planarian mitochondria. I. Heterogeneity of cytochrome c oxidase subunit I gene sequences in the freshwater planarian, Dugesia japonica [14].

Associations of Planarians with chemical compounds

• We recently developed a metric that quantified an acute cocaine withdrawal phenomenon in planarians [15].
• Circadian rhythms of melatonin-synthesizing enzyme activities and melatonin levels in planarians [16].
• Reinforcing properties of dopamine agonist, methamphetamine, for planarians were examined with the conditioned place preference (CPP) procedure [17].
• Reinforcing effects of methamphetamine in planarians [17].
• These results suggest that either D-glucose and 2-deoxy-D-glucose compete with a common cocaine and kappa-opioid transport mechanism or that the development of physical dependence (or the inhibition of abstinence-induced withdrawal) in planarians requires energy supplied from glucose metabolism [18].

Gene context of Planarians

• FGFR-related gene nou-darake restricts brain tissues to the head region of planarians [3].
• Somatostatin-like peptide and regeneration capacities in planarians [19].
• The involvement of Pax6 and six1 and six3 genes, which encode highly conserved transcription factors, in the genetic control of eye development in organisms ranging from planarians to humans argues strongly for a monophyletic origin of the eye [20].
• The presence of a neuropeptide immunologically related to somatostatin (SRIF) has been investigated in the neurosecretory cells of two regenerating planarian species (Dugesia lugubris and Dendrocoelum lacteum) [19].
• An MCM2-related gene is expressed in proliferating cells of intact and regenerating planarians [21].

Analytical, diagnostic and therapeutic context of Planarians

• We identified four guanine nucleotide binding protein (G protein)-coupled receptors from planarians by polymerase chain reaction (PCR) with degenerate primers [22].
• HPLC with fluorometric detection analysis revealed that the serotonin levels of planarians maintained under a 12:12h light:dark cycle showed significant diurnal variations with a trough in the middle of the dark phase [13].
• In the freshwater planarian Dugesia japonica, which belongs to the most primitive metazoan phylum, serotonin (5-hydroxytryptamine) was detectable by both immunohistochemistry and high-performance liquid chromatography (HPLC) with fluorometric detection [13].
• 1. Dopamine, serotonin and, in lesser amounts, norepinephrine were detected in Dugesia gonocephala using electrochemical detection coupled with liquid chromatography (LCED) [23].
• METHODS: Following the homogenization of planarians in aqueous solvent (perchloric acid, L-cystine, and Na(2)EDTA) and centrifugation of supernatant (14,000 x g at 4 degrees C for 20 min), 5-HT was measured using HPLC (aqueous citric acid buffer mobile phase; 5-microm C(18) column with fluorescence detection, 280/340 nm) [24].

References