169,747 research outputs found
Mycocoenological studies in some Mediterranean forest ecosystems (province of Siena, Italy).
No full textIn the last 20 years, the scientific community has shown increasing interest in questions related to biodiversity. Knowledge of biodiversity is a prerequisite for mapping the distribution of species and for the conservation of the organisms populating ecosystems. Here we report the results of mycocoenological research in various types of forest ecosystems (evergreen oak woods of the hill and coastal belts, hill and montane chestnut woods, natural and artificial fir woods, acidophilous and basophilous deciduous oak woods) in central-southern Tuscany, Italy. This research provides a fairly complete picture of the fungal communities of these ecosystems, as well as the similarities and differences between them. The identification of exclusive differential species of each type of forest community provides information about the ecology of the different fungal species.Durant ces vingt dernières années, la communauté scientifique a montré un intérêt croissant au sujet des études concernant la biodiversité. La connaissance de la biodiversité est un préalable indispensable pour dresser une carte de la distribution des espèces et pour la conservation des organismes qui peuplent les écosystèmes. Les auteurs reportent les résultats de recherches mycocoenologiques dans plusieurs écosystèmes forestiers (chênaies sempervirentes de collines ou en situation côtière, châtaigneraies de colline et de montagne, sapinières naturelles et artificielles, chênaies caduques acidophiles et basiphiles) en Toscane centrale et du sud. Ce travail décrit de manière assez exhaustive les communautés fongiques des écosystèmes considérés ainsi que leurs ressemblances et différences. L’identification d’espèces différentielles exclusives de chaque type de communauté forestière permet de documenter l’écologie des diverses espèces de champignons.Laganà Angela, Salerni Elena, Barluzzi Carla, Perini Claudia. Mycocoenological studies in some Mediterranean forest ecosystems (province of Siena, Italy). In: Ecologia mediterranea, tome 27,2001. pp. 125-140
Fungal communities in Mediterranean and Submediterranean woodlands
No full textA summary of data based on several mycocoenological studies, carried out in a belt extending from the Tyrrhenian coast to the foot of the C Apennines, is presented. The studies, concerning macromycetes, have been carried out in mediterranean and submediterranean communities; juniper scrubs on sandy dunes and evergreen oak woods of the Maremma coast; evergreen oakwoods, heathlands, and chestnut coppices of the hills; chestnut coppices and fir woods of submontane areas. Association between c700 fungal species, collected in 5.5 ha, and the seven phytocoenoses are analysed. Species diversity is noteworthy: 14.4% are species widely distributed in the phytocoenoses and 54.9% are associated with only one type of vegetation community
Role of nitric oxide and melanogenesis in the accomplishment of anticryptococcal activity by the BV-2 microglial cell line.
No full textJ Neuroimmunol. 1995 Apr;58(1):111-6.
Role of nitric oxide and melanogenesis in the accomplishment of anticryptococcal activity by the BV-2 microglial cell line.
Blasi E, Barluzzi R, Mazzolla R, Tancini B, Saleppico S, Puliti M, Pitzurra L, Bistoni F.
SourceDepartment of Biomedical Sciences, University of Modena, Italy.
Abstract
In the present paper, we investigated the involvement of cryptococcal melanogenesis and macrophage nitric oxide (NO) production in the accomplishment of anticryptococcal activity by microglial effector cells, using the murine cell line BV-2. We demonstrate that the constitutive levels of anticryptococcal activity exerted by BV-2 cells is significantly enhanced upon interferon gamma plus lipopolysaccharide treatment. The phenomenon, which occurs with no enhancement of phagocytic activity, is associated with the production of high levels of NO and is abolished by addition of NG-monomethyl-L-arginine. Comparable patterns of results are observed employing either unopsonized or opsonized microbial targets, the latter microorganisms being markedly more susceptible to BV-2 cell antimicrobial activity. Furthermore, melanization of Cryptococcus neoformans significantly reduces its susceptibility to BV-2 antimicrobial activity, regardless of the fact that activated macrophages or opsonized microorganisms have been employed. In conclusion, our results provide evidence that NO-dependent events are involved in the fulfillment of anticryptococcal activity by activated microglial cells and that fungal melanization is a precious escamotage through which C. neoformans overcomes host defenses.
PMID: 773044
Biodiversità nel Senese: Flora macromicetica nel XX secolo.
No full textAccademia delle Scienze di Siena detta de’ Fisiocritici, Memorie XI: 33
Microglial cell-mediated anti-Candida activity: temperature, ions, protein kinase C as crucial elements.
No full textAn in vitro established microglial cell line, BV-2, constitutively exhibits high levels of anti-Candida activity. To elucidate the cascade of events leading to the accomplishment of such activity, we studied its dependence on temperature and ion availability. The role of protein kinases has also been studied by the specific inhibitors, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H7) and N-(2-guanidinoethyl)-5-isoquinoline sulfonamide hydrochloride (HA 1004). We found that (a) the BV-2 cell/Candida conjugate formation is a discrete step, temperature-, ion- and protein kinase-independent; (b) the phagocytic event, which is protein kinase-independent, is significantly impaired by temperature decrease and ion deprivation; (c) the fulfillment of anti-Candida effects is strictly dependent upon temperature, ion availability and functional protein kinase. Functional protein kinase C, but not other kinases, is required for the accomplishment of anti-Candida activity, which, in fact, is selectively abrogated by H7 but not HA. Furthermore, protein kinase C activators, such as 12-O-tetradecanoylphorbol 13-acetate (TPA) or 1-oleoyl-2-acetyl glycerol (OAG), consistently potentiate BV-2 cell-mediated anti-Candida activity, the phenomena being dose-dependent. These results indicate that the multistep events leading a microglial cell to express anti-Candida activity can be dissected and differentiated for biochemical and biological demands, the latest along the cascade being the most demanding steps
Differential Host Susceptibility to Intracerebral Infections with Candida albicans and Cryptococcus neoformans
No full textTo investigate the immune defense mechanisms employed against fungi in the brain, mice were experimentally infected by intracerebral inoculation of Candida albicans or Cryptococcus neoformans. Parameters such as median survival time and numbers of yeast cells in the brains were assessed for naive and immunomodulated mice. We found that no mice survived either C. albicans or C. neoformans challenge at doses of .106 yeast cells per mouse. However, when the inoculum size was decreased ('105 yeast cells per mouse), C. albicans was no longer lethal (100%S survival), whereas 100 and 70%o of the mice still succumbed to challenge doses of 104 and 103 C. neoformans yeast cells, respectively. Pharmacological manipulation and transfer experiments revealed that the myelomonocytic compartment had a minor role against C. neoformans but was deeply involved in thecontrol of intracerebral C. albicans infection. By counting the number of yeast cells in the brains of naive and immunomodulated animals, we established that, unlike C. albicans, C. neoformans remained essentially in the brain, where massive colonization and damage occurred whether naive or immunomodulated defensemechanisms were employed by the host. Overall, these data suggest that the differential role of the myelomonocytic compartment, together with the diverse tropisms of the two fungi, can explain the different development and outcome of intracerebral C. albicans and C. neoformans infections
Periodicity, fluctuations and successions of macrofungi in fir forests (Abies alba Miller) in Tuscany, Italy
No full textThe present study, carried out in natural and planted Abies alba Miller woods, was undertaken as a contribution to
knowledge of temporal changes occurring in fungal communities. Moreover, notes on fungal species and fungal communities
in this type of wood are given. Correlations between meteorological variables and fungi (number of species and number of carpophores, as total or divided into trophic groups) were tested by Pearson’s product-moment coefficient. On a short time
scale, weather parameters clearly play a major role, affecting periodicity and fluctuations; on a long time scale (10 years or more), correspondence analysis (CA) indicate that vegetation parameters and forest evolution affect successions
Anticryptococcal Resistance in the Mouse Brain: Beneficial Effects ofLocal Administration of Heat-Inactivated Yeast Cells
No full textUsing a murine model, we have previously shown that brain resistance to local infection with opportunistic fungi is affected by manipulation of the host myelomonocytic compartment. Here, we demonstrate thatintracerebral administration of heat-inactivated Cryptococcus neoformans (H-CN) yeast cells results in a consistent enhancement of mouse survival to subsequent local challenge with lethal doses of C. neoformans. The phenomenon, more pronounced upon double H-CN treatment, is associated with (i) massive local inflammatoryresponse, (ii) reduced growth of the fungus within the brain, and (iii) induction of delayed-type hypersensitivity. Moreover, H-CN treatment confers protection against local heterologous challenges. Our data provide initial evidence that intracerebral administration of H-CN results in the establishment of aspecific and specific immune responses; the mechanisms of elicitation and relative contributions to host antimicrobial resistance remain to be elucidated.Using a murine model, we have previously shown that brain resistance to local infection with opportunistic fungi is affected by manipulation of the host myelomonocytic compartment. Here, we demonstrate that intracerebral administration of heat-inactivated Cryptococcus neoformans (H-CN) yeast cells results in a consistent enhancement of mouse survival to subsequent local challenge with lethal doses of C. neoformans. The phenomenon, more pronounced upon double H-CN treatment, is associated with (i) massive local inflammatory response, (ii) reduced growth of the fungus within the brain, and (iii) induction of delayed-type hypersensitivity. Moreover, H-CN treatment confers protection against local heterologous challenges. Our data provide initial evidence that intracerebral administration of H-CN results in the establishment of a specific and specific immune responses; the mechanisms of elicitation and relative contributions to host antimicrobial resistance remain to be elucidated
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