Data/hora: 20/06/2024 10:24:49

Biblioteca(s): 	Embrapa Florestas.	
Data corrente: 	02/10/2008	
Data da última atualização: 	02/10/2008	
Autoria: 	LAPIED, E.; MOUDILOU, E.; NAHMANI, N. Y.; EXBRAYAT, J.-M.	
Título: 	Programmed cell death in earthworms during the first steps of tissue regeneration.	
Ano de publicação: 	2008	
Fonte/Imprenta: 	In: INTERNATIONAL COLLOQUIUM ON SOIL ZOOLOGY, 15; INTERNATIONAL COLLOQUIUM ON APTERYGOTA, 12., 2008, Curitiba. Biodiversity, conservation and sustainabele management of soil animal: abstracts. Colombo: Embrapa Florestas. Editors: George Gardner Brown; Klaus Dieter Sautter; Renato Marques; Amarildo Pasini. 1 CD-ROM.	
Idioma: 	Inglês	
Conteúdo: 	Low invertebrates, such as cnidarians, plathyhelminthes or annelids, including earthworms, are
well known for their great capacity of tissue regeneration as response to various kinds of natural
or triggered trauma, until complete amputation of a part of the body. In addition, Programmed
Cell Death (PCD) has been found to take an important part in this process, by eliminating
defecting cells during cell proliferation and tissue reorganisation, thus avoiding apparition and
development of tumoral cells. However, if the capacity of regeneration is well documented in
earthworms, very few is known about PCD in these organisms, on a hand, and its potential role
and activity during tissue regeneration, on the other hand.
Programmed cell death was investigated in 2 species of earthworms in normal conditions and
during the first 24 hours of body regeneration after amputation of the 20 last segments, by
immunohistochemical localisation using TUNEL labelling, which allow a direct visualisation of
the nuclear DNA fragmentation, as early step of the apoptotic process. Studied species were
the endogeic Aporrectodea caliginosa and the epigeic Nicodrilus nocturnus. In normal conditions
and for both species, an apoptotic background activity was observed and mainly localised within
the epithelial tissue of the intestine wall, particularly in the typhlosolis, and within the chloragog
cells. Epithelial cells of the intestine wall are implicated in the intestinal absorption while chloragog
tissue is connected to storage of absorbed elements, enzyme production and blood filtration. In
addition, very few apoptotic background activity was detectable as well in the body wall musculature
as in the cuticule. However, after amputation and for both species, a very intense apoptotic
activity occurred in the area of regeneration during the 24 following hours and concerned a large
range of tissue types. As in normal conditions, apoptotic cells were concentrated within the
epithelial tissue of the intestinal wall and the chloragog cells, but a strong increasing in the
density of apoptotic cells also occurred within the longitudinal and circular musculature of the
body wall, and becoming spectacular in the cuticule.
This preliminary work underlined the occurrence of programmed cell death in earthworms as
response to tissue regeneration, and the main localisation of the apoptotic cells during the first
hours of this process. These results, coupled to others which found apoptosis as response to
metal contamination in earthworms could become the basis of new biomarkers linked to
physiological responses of earthworms to environmental stresses.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Florestas (CNPF)	
Exemplares: 	CNPF - (43765-1) - UPE - PL - -- - CD0305 -  -  - DIS