ABSTRACT
Autophagy-related gene 5 (Atg5) plays an essential role in autophagy, the loss of its function impairs neurogenesis and axon regeneration. However, the biological function of Atg5 has not been characterized in planarian. Planarian is an ideal model for the study of brain regeneration. It can regenerate a new brain de novo in 1 week following amputation. To explore the role of Atg5 in planarian brain regeneration, we dissected the molecular characteristics of Atg5 in planarian Dugesia japonica (DjAtg5) and examined its function by RNAi. The full-length cDNA of DjAtg5 is 1 014 bp encoding 284 amino acids. The deduced amino sequence of DjAtg5 contains the functional Pfam domain of ATG5 and highly conserved residues for ATG5-ATG12 interaction. After amputation, the transcrips of DjAtg5 are increased and mainly distributed in the newly regenerated brain on day 3-5 of regeneration. However, knockdown of DjAtg5 by RNAi does not impair the regeneration ability and brain structure reformation, nor affects the neoblasts proliferation. Our results suggest that DjAtg5 participates in re-formation of planarian brain structure following amputation, but it is not an important regulator for planarian regeneration. However, autophagy inhibitor 3-MA can block planarian regeneration, which suggests that autophagy is necessary for planarian regeneration.
ABSTRACT
Objective To establish a pure planarian Dugesiaasexual strain in China.Methods The planarian worms were collected from a wild stream,and then made the worm grow after amputation in the lab.To establish an asexual strain through cutting and culturing for the single worms.Results After ten years and more than ten thousand experiments,an asexual pure planarian strain Dugesia ZB-1 originated from Shandong Zibo area was established.It grows stably under laboratory controlled conditions.Conclusions The establishment of DugesiaZB-1 Priovides a solid foundation for further experiments and promoting planarian research in our country and participation in the field of the international planarian research.
ABSTRACT
Four hundred specimens of Girardia (=Dugesia) tigrina separated in groups of 5 were subjected to concentrations of 10, 25 and 50 ppm diazepam (DZP) and 1, 5 and 10 ppm of ivermectin (IVM), substances with actions associated with ionophore chlorine and GABA receptors in neuromuscular endings in various animals. The period of turbellarians exposure at different concentrations used was 3 h, for DZP while those to IVM were 30, 60, 120 minutes, 12 and 24 h for each tested concentration. In groups exposed to DZP hyperkinetic and type "C" and screw like movements were observed in all concentrations. However, at concentrations of 50 and 25 ppm, the pharynx was protruded in 100% of the specimens followed by detachment at concentration of 50 ppm and 60% at a concentration of 25 ppm. Mortality reached 100% 24 hours after exposure to a concentration of 50 ppm and 30% of planarians became degenerated at a concentration of 25 ppm. Planarians submitted to concentrations of 10 and 25 ppm remained alive and without hyperkinetic movements 48 hours after exposure. In IVM exposed groups, hyperkinetic and contractile movements were observed as well as type "C" screw like movements in all tested concentrations and time dependent. The group exposed for 24 hours showed a time dependent variation in mortality from 0 to 100%. The turbellarians were alive for 48 hours in 1 ppm during 12 hours of exposure but with 24 hours of exposure the mortality reaches 20%. The data indicate a time and concentration dependent relationship in the mode of action of these drugs.
Quatrocentos exemplares de Girardia (=Dugesia) tigrina separados em grupos de 5 foram submetidos a concentrações de 10, 25 e 50ppm de diazepam (DZP) e 1, 5 e 10ppm de ivermectina (IVM), substâncias com ações associadas ao ionóforo cloro e receptores GABA em terminações neuromusculares em vários animais. O tempo de exposição dos turbelários às diferentes concentrações utilizadas de DZP foi de 3 horas, enquanto para cada concentração de IVM os exemplares permaneceram expostos durante 30, 60, 120 minutos, 12 e 24 horas. Nos grupos expostos ao DZP foram verificados movimentos hipercinéticos tipo parafuso e tipo "C" e exposição da faringe ao exterior em todas as concentrações. Houve perda da faringe em 90% dos espécimes na concentração de 50ppm e 60% em 25ppm. Foi verificado também 100% de mortalidade após 24 horas em concentração de 50ppm e 30% de degeneração dos platyhelminthes na concentração de 25ppm. No exame realizado 48 horas após a exposição, as planárias submetidas às concentrações de 25 e 10 ppm permaneceram vivas e não mais apresentaram movimentos hipercinéticos. Nos grupos expostos à IVM, foram observados movimentos contráteis e movimentos hipercinéticos tipo parafuso e tipo "C" em todas as concentrações e foi dependente do tempo de exposição. O percentual de mortalidade variou de 0 a 100 nas primeiras 24 horas de observação também dependente do tempo de exposição. Em concentração de 1 ppm e até 12 horas de exposição não foi observada mortalidade dos animais até 48 horas após. Entretanto com 24 horas de exposição e exame 24 horas após a mortalidade chega a 20% dos exemplares persistindo até o final do período de observação. Os dados indicam uma relação dependente da concentração e do tempo no modo de ação destas substâncias.
Subject(s)
Planarians , Ivermectin , Receptors, Dopamine , DiazepamABSTRACT
Transposable elements are DNA sequences present in all the large phylogenetic groups, both capable of changing position within the genome and constituting a significant part of eukaryotic genomes. The mariner family of transposons is one of the few which occurs in a wide variety of taxonomic groups, including freshwater planarians. Nevertheless, so far only five planarian species have been reported to carry mariner-like elements (MLEs), although several different species have been investigated. Regarding the number of copies of MLEs, Girardia tigrina is the only planarian species in which this has been evaluated, with an estimation of 8,000 copies of the element per haploid genome. Preliminary results obtained in our laboratory demonstrated that MLE is found in a large number of different species of planarians, including terrestrial. With this in mind, the aim was to evaluate the occurrence and estimate the number of MLE copies in different planarian species collected in south Brazil. Twenty-eight individuals from 15 planarian species were analyzed. By using PCR and the hybridization of nucleic acids, it was found that MLE was present in all the analyzed species, the number of copies being high, probably over 10³ per haploid genome.