100 research outputs found
IL RUOLO DELLE MAP KINASI NELLA RISPOSTA DI Trichoplax adhaerens A STRESS TERMICO
No full textTrichoplax adhaerens è l’unica specie sino a oggi descritta del phylum Placozoa. Si
tratta di organismi marini bentonici, piccoli (< 1 mm), piatti e asimmetrici,
lentamente mobili tramite movimento ciliare su fondali duri poco profondi.
Trichoplax è caratterizzato dall’organizzazione più semplice, forse la più primitiva,
tra i metazoi: il corpo piatto consta di due pseudoepiteli privi di lamina basale, tra
cui è compreso un reticolo cellulare sinciziale. La specie si riproduce per scissione
binaria: la riproduzione sessuale non è ancora stata accertata, ma in coltura è
frequente la formazione di oociti putativi in animali apparentemente in fase di
degenerazione. Nonostante la semplicità strutturale, Trichoplax possiede un
genoma complesso che comprende geni di tutte le principali famiglie di geni dei
metazoi. Considerato che tutti i componenti essenziali delle vie di segnalazione
BMP/TGF e JAK/STAT risultano incomplete per la mancanza di componenti
molecolari fondamentali per la trasduzione del segnale, ci si è proposti di studiare il
possibile ruolo delle vie di segnalazione MAPK e STAT nel mediare la risposta a
stress termico. Colture massive (150-250 individui) mantenute a 22 °C sono state
sottoposte a stress termico mediante: esposizione a 30 °C, a 14 °C o a 8 °C fino ai
primi segni di sofferenza degli animali (4,30 h, 24 h, 4,30 h rispettivamente),
quindi lisate con tampone di lisi PBS (11:9). Sono state effettuate analisi di
Western Blotting con anticorpi anti p-MAPKs e p-STATs. I risultati preliminari
mostrano che Trichoplax in risposta a stress termico attiva una via di segnalazione
simile a quelle MAPK e STAT che giocano nei metazoi un ruolo fondamentale per
la sopravvivenza. Vie di segnalazione MAPKs e STATs quindi potrebbero essere
state già attive e funzionali negli stadi iniziali dell’evoluzione dei metazoi
A T T I DELLA SOCIETÀ DEI NATURALISTI E MATEMATICI DI MODENA
No full textTrichoplax adhaerens è l’unica specie sino a oggi descritta del phylum Placozoa. Si
tratta di organismi marini bentonici, piccoli (< 1 mm), piatti e asimmetrici,
lentamente mobili tramite movimento ciliare su fondali duri poco profondi.
Trichoplax è caratterizzato dall’organizzazione più semplice, forse la più primitiva,
tra i metazoi: il corpo piatto consta di due pseudoepiteli privi di lamina basale, tra
cui è compreso un reticolo cellulare sinciziale. La specie si riproduce per scissione
binaria: la riproduzione sessuale non è ancora stata accertata, ma in coltura è
frequente la formazione di oociti putativi in animali apparentemente in fase di
degenerazione. Nonostante la semplicità strutturale, Trichoplax possiede un
genoma complesso che comprende geni di tutte le principali famiglie di geni dei
metazoi. Considerato che tutti i componenti essenziali delle vie di segnalazione
BMP/TGF e JAK/STAT risultano incomplete per la mancanza di componenti
molecolari fondamentali per la trasduzione del segnale, ci si è proposti di studiare il
possibile ruolo delle vie di segnalazione MAPK e STAT nel mediare la risposta a
stress termico. Colture massive (150-250 individui) mantenute a 22 °C sono state
sottoposte a stress termico mediante: esposizione a 30 °C, a 14 °C o a 8 °C fino ai
primi segni di sofferenza degli animali (4,30 h, 24 h, 4,30 h rispettivamente),
quindi lisate con tampone di lisi PBS (11:9). Sono state effettuate analisi di
Western Blotting con anticorpi anti p-MAPKs e p-STATs. I risultati preliminari
mostrano che Trichoplax in risposta a stress termico attiva una via di segnalazione
simile a quelle MAPK e STAT che giocano nei metazoi un ruolo fondamentale per
la sopravvivenza. Vie di segnalazione MAPKs e STATs quindi potrebbero essere
state già attive e funzionali negli stadi iniziali dell’evoluzione dei metazo
La ripresa della vegetazione mediterranea dopo il passaggio degli incendi: il caso di studio del Monte Castellare (PI) - Toscana nord-occidentale
No full textIn Mediterranean ecosystems, wildfires are a key factor that affects vegetation and landscapes. In particular, recurrent wildfires are dramatically dangerous because they can compromise ecosystem resilience. In this view, the present work aimed to study the effects of fire events on the Mediterranean vegetation of Castellare Mount (Pisa). Castellare Mount seemed an interesting study place since two wildfires occurred in 2008 and 2009. The study area was divided into three sites: one site interested by the wildfire event occurred in 2009, another site interested by the wildfire event occurred in 2008, and a control site. Seven dominant plant species (Arbutus unedo L., Daphne gnidium L., Erica arborea L., Myrtus communis L., Phillyrea angustifolia L., Pinus pinaster Aiton and Quercus x morisii Borzì) were selected in each study site. For each species an index of flammability (IF) was calculated, following a non-destructive protocol that took into account seven functional traits related to leaves, twigs, canopy branching, standing litter, and volatile oils production. Moreover, a global flammability index was calculated for each study site. Results showed that all the plant species had quite high values of flammability, which could be explained by their adaptations to fire. In fact, all the taxa examined were active pyrophytes, whose regeneration are stimulated by fire events. However, vegetation survey highlighted a slower process of plant community recovery in the first year after the wildfire event than those observed in the subsequent years. In conclusion, recurrent wildfires are confirmed extremely dangerous because they compromise the recovery of Mediterranean vegetation
Differenziamento in vitro delle sottopopolazioni NK CD56dim e CD56bright da progenitori empoietici CD34+
No full text
DEVELOPMENTAL RELATIONSHIP AMONG CD56BRIGHT, CD56DIM NK CELLS AND TYPE-2 INNATE LYMPHOID CELLS (ILC2)
No full textInnate lymphoid cells (ILCs) are immune effector cells which, differently from
T and B lymphocytes, do not express rearranged receptors. Besides NK cells that
belong to the ILC1 group, the novel lineages have raised a question regarding their
developmental relationship. To this regard, the ILC groups differ not only for their
effector functions but also for their anatomical localization, suggesting the possibility
that a common progenitor may migrate and differentiate in different ILCs, depending
on the tissue microenvironment. On the other hand, we have recently indicated
that CD56dim and CD56bright NK cells, both considered in the ILC1 group, originate
from two distinct precursors which generate cells with convergent phenotypes and
functions. CD56bright /CD117+ NK cells, differently from CD56dim/CD117neg NK cells,
early express natural cytotoxicity receptors (NCRs), while lately upregulate granzyme-B,
perforin, LFA-1, and CD94-CD159a heterodimer (1). Within the ILC family,
the recently defined type-2 ILCs (ILC2), characterized by CD161+/CD117+/NKp44neg
phenotype, typically produces IL-13 and IL-5 (2). Interestingly, a similar subset had
been described several years ago (3). At that time, these cells had been considered
an immature stage of NK cell differentiation which, under opportune cytokine stimulation,
upregulated CD56 and CD94 antigens, produced IFN-gamma and became
cytotoxic. New evidences suggest that, rather than an immature NK cell stage, these
cells represent a mature lineage which, similar to CD56bright NK cells, early expresses
CD117 and CD161 antigens. However, during their differentiation, ILC-2 upregulate
granzyme B and CD94 in absence of NCRs, thus resembling the CD56dim NK cell lineage
in their developmental pattern of antigen expression.
References
[1] Zamai et al. (2012) Cytotoxic functions and susceptibility to apoptosis of human CD56(bright) NK
cells differentiated in vitro from CD34+ hematopoietic progenitors. Cytometry A 81(4):294-302.
[2] Mjosberg et al. (2011) Human IL-25- and IL-33-responsive type 2 innate lymphoid cells are defined
by expression of CRTH2 and CD161. Nat Immunol 11;12(11):1055-62.
[3] Loza et al. (2002) Expression of type 1 (interferon gamma) and type 2 (interleukin-13, interleukin-5)
cytokines at distinct stages of natural killer cell differentiation from progenitor cells.
Blood 15;99(4):1273-81
Lethal and sub-lethal effects induced by Campylobacter jejuni lysates on CaCo-2 cells
No full textIntroduction: Campylobacter jejuni is a Gram-negative spiral-shaped bacterium that is the most prevalent cause of bacterial diarrhea in humans and that might be responsible for 500 million cases of gastroenteritis world over each year. An important C. jejuni virulence factor is the Cytolethal Distending Toxin (CDT) that is thought to be associated with C. jejuni-induced local acute inflammation involved in enterocolitis. Our research evaluates the sequence of lethal and sub-lethal events in CaCo-2 cells, as a model of intestinal epithelium, exposed to lysates of three distinct strains, C. jejuni ATCC 33291 and C. jejuni ISS 1, compared to C. jejuni 11168H cdtA mutant.
Methods: Cell lysates of C. jejuni ATCC 33291, C. jejuni ISS 1 and C. jejuni 11168H cdtA mutant strains were added to CaCo-2 cell monolayers and, after 24, 48 and 72 hours, cells were analysed by means of flow cytometry and confocal microscopy, to detect DNA content, death features, mitochondrial-lysosomal network and autophagic pathway.
Results: C. jejuni lysates induced cell cycle arrest in G2/M phase, as highlighted by propidium iodide staining, and induction of apoptosis, revealed by 7-AAD. The C. jejuni ISS 1 wild-type strain mainly induced lysosomal alterations and the most relevant mitochondrial modifications. Instead, the C. jejuni ATCC 33291 strain causes changes in autophagic pathway as indicated by the results from monodansylcadaverine (MDC) staining, a specific autophagolysosomal marker, suggesting that CaCo-2 cells respond to stimuli by activating the autophagic machinery, largely involved in bacterial infections.
Conclusions: Our results suggest that C. jejuni lysates-treated CaCo-2 cells displayed different features, depending on the particular strain. In fact, lysates are able to induce lethal and sub-lethal effects differently targeting mitochondrial, lysosomal and autophagosomal compartments. These data are linked to the potentially complex interactions that underlay the etiopathogenesis of enteric infections
Coinvolgimento mitocondriale e lisosomiale indotto da lisati batterici di Campylobacter jejuni in cellule HeLa
No full textDefective Autophagy, Mitochondrial Clearance and Lipophagy in Niemann-Pick Type B Lymphocytes
No full textNiemann-Pick disease type A (NP-A) and type B (NP-B) are lysosomal storage diseases (LSDs) caused by sphingomyelin accumulation in lysosomes relying on reduced or absent acid sphingomyelinase. A considerable body of evidence suggests that lysosomal storage in many LSD impairs autophagy, resulting in the accumulation of poly-ubiquitinated proteins and dysfunctional mitochondria, ultimately leading to cell death. Here we test this hypothesis in a cellular model of Niemann-Pick disease type B, in which autophagy has never been studied. The basal autophagic pathway was first examined in order to evaluate its functionality using several autophagy-modulating substances such as rapamycin and nocodazole. We found that human NP-B B lymphocytes display considerable alteration in their autophagic vacuole accumulation and mitochondrial fragmentation, as well as mitophagy induction (for damaged mitochondria clearance). Furthermore, lipid traceability of intra and extra-cellular environments shows lipid accumulation in NP-B B lymphocytes and also reveals their peculiar trafficking/management, culminating in lipid microparticle extrusion (by lysosomal exocytosis mechanisms) or lipophagy. All of these features point to the presence of a deep autophagy/mitophagy alteration revealing autophagic stress and defective mitochondrial clearance. Hence, rapamycin might be used to regulate autophagy/mitophagy (at least in part) and to contribute to the clearance of lysosomal aberrant lipid storage
Ultrastructural analyses support different morphological lineages in the phylum Placozoa Grell, 1971
No full textThe morphology and ultrastructure of 10 clonal placozoan lineages were studied. We scored several morphological characters at a cellular and intracellular level and identified a number of morphological differences among clones. Some differences appear clone specific and allow recognizing five distinct lineages based on morphological criteria only. These data will be crucial for a yet to be established placozoan systematics. Furthermore, we here describe three new diagnostic morphological characters for Placozoa: a new structure in the upper epithelium, called ‘‘concave disc,’’ two distinct subpopulations of fiber cells, and especially small cells in the body margin. Besides the fiber cells appear to be arranged in several layers forming a complex, three-dimensional net not previously described. We also describe the marginal cells as the formerly suggested potential stem-cell type. The basic morphology is revised
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