Paolo Deri - Academia.edu (original) (raw)

Papers by Paolo Deri

Rend. Accad. Naz. Lincei, ser. VIII, 1977

SUMMARY. - Specimens of the freshwater planarian Dugesia benazzii, collected in two diffe... more SUMMARY. - Specimens of the freshwater planarian Dugesia benazzii, collected in two different localities of the island of Corsica, showed in the first period of laboratory culture (I966-I972) a triploid complement (24 chromosomes) in the somatic cells, a hexaploid com plement in the female line and a diploid complement in the male line.
New research has now demonstrated the occurrence in the somatic and in both germ lines
of metacentric B-chromosomes, varying in number from I to 3· The Authors point out that these new chromosomes appeared almost simultaneously in the two different cultures, and in one of them in the three specimens kept isolated for about five years. I t is also worthy of notice that this is the first observation of the presence of B-chromosomes in polyploid animals.

Atti Soc. Toscana Sci. Naturali, Memorie, serie B, 1981

Abstract - Karyology of a popùlation of Dugesia benazzii (Tricladida Paludi cola) with... more Abstract - Karyology of a popùlation of Dugesia benazzii (Tricladida Paludi cola) with B-chromosomes. A karyological analysis has been carried out on specimens of the planarian Dugesia benazzii collected in Conca stream (Corsica). In this popu lation, which reproduces mainly by fìssion, only few individuals become sexual; the latter condit on,
polysomic. sets with rather large numerica!variations (from 18 to 28 chromosomes).
In 85% of the cells examined, B-chromosomes, varying in number from l to 4, have also been observed. This study provides also a quantitative analysis of the
·karyometric data concerning both standard and B-chromosomes.

Biologia.-On the origin of heterogeneous chromosome sets in some fissiparous planarians. N ota di... more Biologia.-On the origin of heterogeneous chromosome sets in some fissiparous planarians. N ota di G iu se ppin a B enazzi L e ntati (,) e P aolo D eri (** (* * *) >, presentata (*"> dal Socio M. B enazzi. RIASSUNTO.-Sono state studiate due popolazioni del Triclade Paludicolo Dugesia benazzii, appartenenti a due diversi biotipi cariologia, da molti anni allevate in laboratorio ed in cui è stato possibile cogliere fasi iniziali di variazioni del genoma, apparentemente colle gate alla scissiparità. Gli AA., tuttavia, in base al complesso delle ricerche compiute dal gruppo pisano ed a quelle eseguite da altri studiosi, giungono alla conclusione che, seppure in molti casi i due fatti appaiano concomitanti, essi non possono considerarsi geneticamente correlati.

Symposium 'Stem Cells, Development and Regenerative Medicine' (SCDRM2014) - Salerno (Italy), 2014, 6-7 June, 2014

Belg J Zool, 2001

... Leonardo Rossi1, Renata Batistoni1, Alessandra Salvetti2, Paolo Deri1, Fabrizio Bernini1, Ila... more ... Leonardo Rossi1, Renata Batistoni1, Alessandra Salvetti2, Paolo Deri1, Fabrizio Bernini1, Ilaria Andreoli1, Alessandra Falleni2 and Vittorio Gremigni2 1Dipartimento di ... CALLAERTS, P., AM MUNOZ-MARMOL, S. GLARDON, E. CASTILLO, H. SUN, W.-H. LI, WJ GEHRING & E ...

The International journal of developmental biology, 2003

SWI/SNF-related complexes include proteins implicated in the regulation of gene expression by chr... more SWI/SNF-related complexes include proteins implicated in the regulation of gene expression by chromatin remodelling. We have identified in planarians, invertebrates well-known for their regenerative capability,the cDNA of a novel gene, DjXnp, which encodes a protein of 1,076 amino acids, containing seven helicase domains similar to those found in the SNF2-like family members. Sequence comparison reveals a significant degree of similarity of DjXNP with mammalian XNP/ATRX proteins. In situ hybridization experiments performed on intact and regenerating planarians demonstrated that DjXnp transcripts were distributed in mesenchymal cells and were especially abundant in nerve cells. During anterior regeneration, DjXnp was detected in the blastemal area where the nervous system is newly forming. This expression pattern reveals extensive similarities with that described for mammalian XNP/ATRX, suggesting that these genes may have a conserved function at the cellular level.

Cellular and molecular life sciences : CMLS, 2008

Planarians possess amazing abilities to regulate tissue homeostasis and regenerate missing body p... more Planarians possess amazing abilities to regulate tissue homeostasis and regenerate missing body parts. These features reside on the presence of a population of pluripotent/totipotent stem cells, the neoblasts, which are considered as the only planarian cells able to proliferate in the asexual strains. Neoblast distribution has been identified by mapping the cells incorporating bromodeoxyuridine, analyzing mitotic figures and using cell proliferation markers. Recently identified molecular markers specifically label subgroups of neoblasts, revealing thus the heterogeneity of the planarian stem cell population. Therefore, the apparent totipotency of neoblasts probably reflects the composite activities of multiple stem cell types. First steps have been undertaken to understand how neoblasts and differentiated cells communicate with each other to adapt the self-renewal and differentiation rates of neoblasts to the demands of the body. Moreover, the introduction of molecular resource data...

International journal of Developmental Biolgy, 2003

ABSTRACT SWI/SNF-related complexes include proteins implicated in the regulation of gene expr... more ABSTRACT SWI/SNF-related complexes include proteins implicated in the regulation of gene expression by chromatin remodelling. We have identified in planarians, invertebrates well-known for their regenerative capability, the cDNA of a novel gene, DjXnp, which encodes a protein of 1,076 amino acids, containing seven helicase domains similar to those found in the SNF2-like family members. Sequence comparison reveals a significant degree of similarity of DjXNP with mamma- lian XNP/ATRX proteins. In situ hybridization experiments performed on intact and regenerating planarians demonstrated that DjXnp transcripts were distributed in mesenchymal cells and were especially abundant in nerve cells. During anterior regeneration, DjXnp was detected in the blastemal area where the nervous system is newly forming. This expression pattern reveals extensive similarities with that described for mammalian XNP/ATRX, suggesting that these genes may have a conserved function at the cellular level.

KEY WORDS: planarians, regeneration, SWI/SNF, DNA helicase, XNP/ATRX

Development

An ultrastructural analysis has been made of certain ovarian chambers undergoing ab-normal develo... more An ultrastructural analysis has been made of certain ovarian chambers undergoing ab-normal development. The earliest morphological change in these chambers consists of thealteration of the nuclear material which is then followed by engulfment of portions of thenurse cell cytoplasm, including the nuclear fragments, into the overlying follicle cells. Thecontinuation of this process leads to the progressive disappearance of nurse cells with theconcomitant formation of huge dense vacuoles in the follicle layer. The morphological featuresdescribed in the present investigation are similar to those found in other tissues and inter-preted as leading to cell death. It is suggested that certain ovarian chambers undergo celldeath as a result of the incapability of furthering their development. The role played by celldeath in oogenesis is also discussed on the basis of the current literature.

International Journal of Developmental Biology, 2003

Monitore Zoologico Italiano-Italian Journal of Zoology, 1980

SUMMARY A histological and cytological examination of the male gonads of numerous ex-fissiparous ... more SUMMARY A histological and cytological examination of the male gonads of numerous ex-fissiparous specimens of Dugesia gonocephala s.l. (Tricladida Paludicola) from various European and extra-European localities showed that spermatogenesis is notably altered. Despite inter-populational variations, the majority of the specimens had small testicular nodules containing spermatogonia, spermatocytes I and rare spermatids; only a minority had larger follicles occasionally containing small bunches of sperm which, however, were much fewer than those found in the testicles of normally sexualized individuals. The anomalies found in the male gonads, just as those observed in the female gonads during previous research, are due to fission-controlling factors which are present although inhibited in the ex-fissiparous specimens.

Developmental Dynamics 218: 603-614 (2000), 2000

ABSTRACT The minichromosome mainte- nance (MCM2-7) gene family encodes conserved proteins, ... more ABSTRACT The minichromosome mainte- nance (MCM2-7) gene family encodes conserved proteins, which are essential for DNA replication licensing in eukaryotes. They are abundant in proliferating cells, and specific MCM transcripts undergo cell cycle-dependent oscillations. Here we report the characterization of a planarian MCM2 homologue, DjMCM2, which represents the first molecular marker for detecting prolifer- ating cells in planarians. DjMCM2-expressing cells are broadly distributed in the mesenchymal space of the body, with the exception of the ce- phalic region, and are preferentially accumu- lated in the peripheral area of the dorso-lateral mesenchyme, along the anteroposterior axis. During regeneration, no DjMCM2 transcripts are observed within the blastema, according to the current view that this structure is not a prolifer- ation site in planarians. Spatio-temporal changes in DjMCM2 RNA expression pattern in the stump parallel blastema growth, coordinately with the orientation of the cut. X-ray irradiation results in the disappearance of DjMCM2 expression, thus confirming that these transcripts are detected specifically in proliferating cells, visualized as neoblasts by in situ hybridization in dissociated cells. In addition to neoblasts, rare large DjMCM2- expressing cells are observed in macerates of tis- sues excised just below the wound, suggesting that cell types other than neoblasts may be sporadically recruited for proliferation in planarians.
© 2000 Wiley-Liss, Inc.

Key words: Dugesia japonica; regeneration; neoblasts; DNA replication; minichro- mosome maintenance (MCM2-7) proteins

Developmental biology, 2009

In adult organisms, stem cells are crucial to homeostasis and regeneration of damaged tissues. In... more In adult organisms, stem cells are crucial to homeostasis and regeneration of damaged tissues. In planarians, adult stem cells (neoblasts) are endowed with an extraordinary replicative potential that guarantees unlimited replacement of all differentiated cell types ...

Cell Stress and …, 2011

Heat shock proteins (HSPs) play a crucial role in the protection of cells. In the present study, ... more Heat shock proteins (HSPs) play a crucial role in the protection of cells. In the present study, we have identified an hsp90-related gene (Djhsp90) encoding a cytosolic form of HSP90 that is primarily expressed in gastrodermis of the planarian Dugesia japonica. Djhsp90 becomes significantly induced after traumatic amputation or other stress stimuli, such as exposure to X-ray or ultraviolet radiations, heat shock, or prolonged starvation. When Djhsp90 is silenced by ribonucleic acid interference (RNAi), planarians dramatically decrease in size, becoming unable to eat, and die in a few weeks. Our results indicate that this gene plays an essential cytoprotective role in the gastrodermis of planarians and suggest that this chaperone can be involved in autophagic processes that are activated by this tissue.

A new species of the genus Dugesia is described from the Lake Ohrid region in the western part of... more A new species of the genus Dugesia is described from the Lake Ohrid region in the western part of the Balkan Peninsula, forming the first fully documented species description for this genus in the Ohrid area. The morphological species delimitation is supported by complementary molecular, karyological, and cytogenetic data available from the literature. Therefore, species delineation is based on a truly integrative approach. Further, a short account on the degree of freshwater planarian endemicity in the Ohrid region is provided.

Planarian regeneration, based upon totipotent stem cells, the neoblasts, provides a unique opport... more Planarian regeneration, based upon totipotent stem cells, the neoblasts, provides a unique opportunity to study in vivo the molecular program that defines a stem cell. In this study, we report the identification of DjPiwi-1, a planarian homologue of Drosophila Piwi. Expression analysis showed that DjPiwi-1 transcripts are preferentially accumulated in small cells distributed along the midline of the dorsal parenchyma. DjPiwi-1 transcripts were not detectable after X-ray irradiation by whole mount in situ hybridization. Real time reverse transcriptase polymerase chain reaction analysis confirmed the significant reduction of DjPiwi-1 expression after X-ray treatment. However, the presence of residual DjPiwi-1 transcription suggests that, although the majority of DjPiwi-1-positive cells can be neoblasts, this gene is also expressed in differentiating/ differentiated cells. During regeneration DjPiwi-1-positive cells reorganize along the midline of the stump and no accumulation of hybridization signal was observed either in the blastema area or in the parenchymal region beneath the blastema. DjPiwi-1-positive cells, as well as the DjMCM2-expressing neoblasts located along the midline and those spread all over the parenchyma, showed a lower tolerance to X-ray with respect to the DjMCM2-expressing neoblasts distributed along the lateral lines of the parenchyma. Taken together, these findings suggest the presence of different neoblast subpopulations in planarians.