169,905 research outputs found
Muggia e Nervi, il fecondo e complesso rapporto tra un grande maestro e un discepolo illustre
No full textIl rapporto tra il professor Attilio Muggia e Pier Luigi Nervi dagli anni della formazione all'Università di Bologna a quelli dell'apprendistato presso la società anonima per costruzioni cementizi
Niches and adaptation of polyextremotolerant black fungi.
No full textEnvironmental changes such as increased levels of carbon dioxide and UV radiation are usually perceived as a threat to living organisms and associated with shrinking populations and extinction. We frequently forget that some species cope really well with a range of extreme and rapidly changing conditions and may actually benefit from such changes. Black meristematic fungi, for example, are well adapted to high doses of radiation and survive long periods of desiccation. They seem not only robust under moderate stress conditions but seem to adapt and diversify, in agreement with the so-called concept of antifragility. We hypothesise that this behaviour is mediated by the polymer melanin in the cell walls; yet, other protective molecules and phenotypic plasticity play an important role as well. Evolution of these fungi is thought to have originated in the harsh oligotrophic habitats on the surface and subsurface of rocks, but their potentials are much wider than that. Their polyextremotolerance helps them to colonise numerous habitats in which competition with other fungi is low due to stressful conditions. This includes a range of anthropogenic environments and in some cases also animal bodies. Some of these fungi also undergo lichen-like associations with photoautotrophs or benefit from growing on lichens
Phylogenetic placement of some morphologically unusual members of Verrucariales
No full textMost members of Verrucariales, as in other
lichenized lineages, form typical thallus morphologies,
including crustose, squamulose, foliose and rarely subfruticose thalli. Some members occur in humid habitats; however some evolved unusually delicate thallus morphologies, such as minute shelllike disks, microfilamentous cushions or brittle flakes. In this study we aimed to elucidate the phylogenetic placement of such morphologically outstanding taxa. We included in our analyses Agonimia spp., Flakea papillata, Normandina spp. and Psoroglaena spp. and used a multilocus sequence dataset of the Verrucariales (SSU rDNA, LSU rDNA, mtSSU, RPB1). The
resulting hypothesis revealed genus Normandina as a
monophyletic group. Lauderlindsaya was confirmed as a synonym of Normandina. Normandina acroglypta is nested in N. pulchella. Psoroglaena abscondita does not cluster with other species of this genus (P. biatorella and P. stigonemoides) and is related to Verrucula and Placocarpus. Four species of Agonimia form a monophyletic group together with Norrlinia,
whereas A. repleta represents its own clade. Apart
from this latter relationship the phylogenetic relationship
of Flakea and Normandina with other lineages in Verrucariaceae remains elusive with our multilocus dataset. More sequence data of protein-coding loci are required to increase phylogenetic resolution because morphological evolution seems to be dynamic in Verrucariales
A combined molecular and morphological approach to species delimitation in black-fruited, endolithic Caloplaca : high genetic and low morphological diversity
No full textA revision based on the morphological and genetic analyses of 133 specimens of black-fruited, endolithic Caloplaca belonging to subgenus Pyrenodesmia is presented. The material was collected in 16 sites distributed along a transept from Gargano (Central Italy) to the southeastern Alps, from sea level to ca 1500 m. The nuclear ITS was sequenced for all themycobionts and selected representatives of photobionts. Except for the sorediate C. erodens, all species share the same algal lineage of Trebouxia as photobiont. The haplotype analysis of the mycobionts revealed an unexpected, high genetic heterogeneity. Three main morphotypic clusters were recognized among five species [C. albopruinosa (syn. C. agardhiana auct.), C. alociza, C. badioreagens, C. erodens, and C. variabilis]. A phylogenetic analysis, including already available Caloplaca sequence data, revealed that these lichens form a monophyletic group within the genus. For each species, notes on ecology, distribution in Italy, and nomenclature are given
Polyextremotolerant black fungi: oligotrophism, adaptive potential and a link to lichen symbioses
No full textBlack meristematic fungi can survive high doses of radiation and are resistant to desiccation. These adaptations help them to colonize harsh oligotrophic habitats, e.g. on the surface and subsurface of rocks. One of their most characteristic stress-resistance mechanisms is the accumulation of melanin in the cell walls. This, production of other protective molecules and a plastic morphology further contribute to ecological flexibility of black fungi. Increased growth rates of some species after exposure to ionizing radiation even suggest yet unknown mechanisms of energy production. Other unusual metabolic strategies may include harvesting UV or visible light or gaining energy by forming facultative lichen-like associations with algae or cyanobacteria. The latter is not entirely surprising, since certain black fungal lineages are phylogenetically related to clades of lichen-forming fungi. Similar to black fungi, lichen-forming fungi are adapted to growth on exposed surfaces with low availability of nutrients. They also efficiently use protective molecules to tolerate frequent periods of extreme stress. Traits shared by both groups of fungi may have been important in facilitating the evolution and radiation of lichen-symbioses
Phylogeny of rock-inhabiting fungi related to Dothideomycetes
No full textThe class Dothideomycetes (along with Eurotiomycetes) includes numerous rock-inhabiting fungi (RIF), a group of ascomycetes that tolerates surprisingly well harsh conditions prevailing on rock surfaces. Despite their convergent morphology and physiology, RIF are phylogenetically highly diverse in Dothideomycetes. However, the positions of main groups of RIF in this class remain unclear due to the lack of a strong phylogenetic framework. Moreover, connections between rock-dwelling habit and other lifestyles found in Dothideomycetes such as plant pathogens, saprobes and lichen-forming fungi are still unexplored. Based on multigene phylogenetic analyses, we report that RIF belong to Capnodiales (particularly to the family Teratosphaeriaceae s.l.), Dothideales, Pleosporales, and Myriangiales, as well as some uncharacterised groups with affinities to Dothideomycetes. Moreover, one lineage consisting exclusively of RIF proved to be closely related to Arthoniomycetes, the sister class of Dothideomycetes. The broad phylogenetic amplitude of RIF in Dothideomycetes suggests that total species richness in this class remains underestimated. Composition of some RIF-rich lineages suggests that rock surfaces are reservoirs for plant-associated fungi or saprobes, although other data also agree with rocks as a primary substrate for ancient fungal lineages. According to the current sampling, long distance dispersal seems to be common for RIF. Dothideomycetes lineages comprising lichens also include RIF, suggesting a possible link between rock-dwelling habit and lichenisatio
A New Small Drifter for Shallow Water Basins: Application to the Study of Surface Currents in the Muggia Bay (Italy)
No full textA new small drifter prototype for measuring current immediately below the free surface in a water basin is proposed in this paper.
Thedrifter dimensionsmake it useful for shallow water applications.The drifter transmits itsGPS location viaGSMphone network.
The drifter was used to study the trajectory of the surface current in the Muggia bay, the latter containing the industrial harbor of
the city of Trieste (Italy).The analysis has been carried out under a wide variety of wind conditions. As regards the behavior of the
drifter, the analysis has shown that it is well suited to detect the water current since its motion is marginally affected by the wind.
The study has allowed detecting the main features of the surface circulation within the Muggia bay under different meteorological
conditions. Also, the study has shown that the trajectory of the surface current within the bay is weakly affected by the Coriolis
force
The Lichen Connections of Black Fungi
No full textMany black meristematic fungi persist on
rock surfaces—hostile and exposed habitats where
high doses of radiation and periods of desiccation
alternate with rain and temperature extremes. To cope
with these extremes, rock-inhabiting black fungi show
phenotypic plasticity and produce melanin as cell wall
pigments. The rather slow growth rate seems to be an
additional prerequisite to oligotrophic conditions. At
least some of these fungi can undergo facultative,
lichen-like associations with photoautotrophs. Certain
genera presenting different lifestyles are phylogenetic
related among the superclass Dothideomyceta. In this
paper, we focus on the genus Lichenothelia, which
includes border-line lichens, that is, associations of
melanised fungi with algae without forming proper
lichen thalli. We provide a first phylogenetic hypothesis
to show that Lichenothelia belongs to the superclass
Dothideomyceta. Further, culture experiments
revealed the presence of co-occurring fungi in Lichenothelia
thalli. These fungi are related to plant
pathogenic fungi (Mycosphaerellaceae) and to other
rock-inhabiting lineages (Teratosphaeriaceae). The
Lichenothelia thallus-forming fungi represent therefore
consortia of different black fungal strains. Our
results suggest a common link between rock-inhabiting
meristematic and lichen-forming lifestyles of
ascomycetous fungi
An overview of genomics, phylogenomics and proteomics approaches in ascomycota
No full textFungi are among the most successful eukaryotes on Earth: they have evolved strategies to survive in the most diverse environments and stressful conditions and have been selected and exploited for multiple aims by humans. The characteristic features intrinsic of Fungi have required evolutionary changes and adaptations at deep molecular levels. Omics approaches, nowadays including genomics, metagenomics, phylogenomics, transcriptomics, metabolomics, and proteomics have enormously advanced the way to understand fungal diversity at diverse taxonomic levels, under changeable conditions and in still under-investigated environments. These approaches can be applied both on environmental communities and on individual organisms, either in nature or in axenic culture and have led the traditional morphology-based fungal systematic to increasingly implement molecular-based approaches. The advent of next-generation sequencing technologies was key to boost advances in fungal genomics and proteomics research. Much effort has also been directed towards the development of methodologies for optimal genomic DNA and protein extraction and separation. To date, the amount of proteomics investigations in Ascomycetes exceeds those carried out in any other fungal group. This is primarily due to the preponderance of their involvement in plant and animal diseases and multiple industrial applications, and therefore the need to understand the biological basis of the infectious process to develop mechanisms for biologic control, as well as to detect key proteins with roles in stress survival. Here we chose to present an overview as much comprehensive as possible of the major advances, mainly of the past decade, in the fields of genomics (including phylogenomics) and proteomics of Ascomycota, focusing particularly on those reporting on opportunistic pathogenic, extremophilic, polyextremotolerant and lichenized fungi. We also present a review of the mostly used genome sequencing technologies and methods for DNA sequence and protein analyses applied so far for fungi
Forage quality improves but ecosystem multifunctionality declines under drought and frequent cutting in dry grassland mesocosms
No full textDry grasslands are vast, socioeconomically and ecologically important environments, which are increasingly threatened by multiple stressors. We tested whether plant cover composition could mitigate ecosystem services loss under multiple stressors in dry grassland mesocosms by growing the grass sorghum (Sorghum bicolor) alone (Grass cover) or together with the legume serradella (Ornithopus sativus) (Mixed cover) under frequent cutting and/or increasing water stress. We assessed erosion control, carbon sequestration, forage quantity and quality, and soil fertility, individually and simultaneously (i.e., multifunctionality). Contrary to our hypothesis, the Mixed cover did not improve ecosystem services compared to the Grass cover, except for forage quality, which improved by 30%. In general, the stressors had negative effects: cutting reduced erosion control by 20%, forage quantity by 50%, soil fertility by 40% and multifunctionality by 20%, and severe water stress decreased carbon sequestration by 40%, forage quantity by 30%, soil fertility by 10%, and multifunctionality by 10%. Water stress caused 100% serradella mortality, underscoring this legume’s vulnerability to increasing aridity. Combined stressors yielded the lowest service provision. Forage quality was the only service that improved under stress: cutting improved it by 40% and severe water stress by 60%. Our results suggest that while systems combining grasses and legumes may enhance forage quality, grass-dominated systems appear more resilient to multiple stressors in drylands, largely due to their superior efficiency in accessing and conserving limited water and nutrient resources. Given the ongoing trends of aridification and land-use intensification, future research should explore adaptive management strategies that prioritize resource-efficient plant species, foster belowground resource retention, and optimize grazing regimes to sustain resilience and multifunctionality in dry grasslands
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