125 research outputs found
Integrazioni alla flora vascolare dell’Italia centrale.
Additions to the vascular flora of the Central Italy. In this work new floristic records for 46 units are reported for some regions of Central Italy. Particularly 25 are new or confirmed to Abruzzo, 1 is new to Marche and 1 to Molise. In addition new distribution data for 18 units rare or interesting in Abruzzo and 1 in Molise regions have been recorded. The survey was carried out from 2010 to 2015 through field research, revision of herbarium specimens and literature studies. Some recorded species are particularly interesting from a phytogeo¬graphical or conservational point of view as they are very rare in Cen¬tral Italy. The results also show a high presence of new alien species
Impact of sulfur starvation in autotrophic and heterotrophic cultures of the Extremophilic Microalga Galdieria Phlegrea (Cyanidiophyceae)
In plants and algae, sulfate assimilation and cysteine synthesis are regulated by sulfur (S) accessibility from the environment. This study reports the effects of S deprivation in autotrophic and heterotrophic cultures of Galdieria phlegrea (Cyanidiophyceae), a unicellular red alga isolated in the Solfatara crater located in Campi Flegrei (Naples, Italy), where H2S is the prevalent form of gaseous S in the fumarolic fluids and S is widespread in the soils near the fumaroles. This is the first report on the effects of S deprivation on a sulfurous microalga that is also able to grow heterotrophically in the dark. The removal of S from the culture medium of illuminated cells caused a decrease in the soluble protein content and a significant decrease in the intracellular levels of glutathione. Cells from heterotrophic cultures of G. phlegrea exhibited high levels of internal proteins and high glutathione content, which did not diminish during S starvation, but rather glutathione significantly increased. The activity of O-acetylserine(thiol)lyase (OASTL), the enzyme synthesizing cysteine, was enhanced under S deprivation in a time-dependent manner in autotrophic but not in heterotrophic cells. Analysis of the transcript abundance of the OASTL gene supports the OASTL activity increase in autotrophic cultures under S deprivation
Effects of phylogenetic associations on environmental and temporal niche partitioning among sympatric mammals
Mammals have evolved to occupy spatial and temporal niches in order to optimize resource utilization and minimize predation risk or competition. Subsequently, niche partitioning may be influenced by phylogenetic associations, which could have substantial consequences for ecosystem structure and function. We use the output from occupancy models based on camera trapping data to construct a tri-partite network describing the environmental and temporal partitioning of activity among twelve sympatric mammals in the Apennine Mountains of central Italy. We further evaluate if there were any effects of phylogenetic associations on the contributions of species to the properties of this spatio-temporal network. The Apennines form a pristine region in central Italy with a relatively intact Mediterranean mammal fauna. The mammal community in our study consisted of species ranging in size from 300 gs to over 200 kg, and included herbivores, omnivores and predators. There was limited structuring of the network describing environmental and temporal niche use. Furthermore, we did not find any phylogenetic signal in species contributions to network structures, and phylogenetic relatedness among species was not associated with their similarities in environmental or spatial niche use. However, animals appeared to have partitioned environmental niches more than temporal ones, suggesting that spatial variation in resource availability may have been more important than temporal avoidance of predation risk or competition in shaping activity within this mammal community. Our study highlights the need to evaluate under which conditions evolutionary history is influencing contemporary ecological processes
Meta-analysis of multidecadal biodiversity trends in Europe
Local biodiversity trends over time are likely to be decoupled from global trends, as local processes may compensate or counteract global change. We analyze 161 long-term biological time series (15-91 years) collected across Europe, using a comprehensive dataset comprising similar to 6,200 marine, freshwater and terrestrial taxa. We test whether (i) local long-term biodiversity trends are consistent among biogeoregions, realms and taxonomic groups, and (ii) changes in biodiversity correlate with regional climate and local conditions. Our results reveal that local trends of abundance, richness and diversity differ among biogeoregions, realms and taxonomic groups, demonstrating that biodiversity changes at local scale are often complex and cannot be easily generalized. However, we find increases in richness and abundance with increasing temperature and naturalness as well as a clear spatial pattern in changes in community composition (i.e. temporal taxonomic turnover) in most biogeoregions of Northern and Eastern Europe. The global biodiversity decline might conceal complex local and group-specific trends. Here the authors report a quantitative synthesis of longterm biodiversity trends across Europe, showing how, despite overall increase in biodiversity metric and stability in abundance, trends differ between regions, ecosystem types, and taxa.peerReviewe
Hydrogen sulfide causes excision of a genomic island in Pseudomonas syringae pv. phaseolicola
© 2017, The Author(s). Hydrogen sulfide (H2S) is known to be an important signalling molecule in both animals and plants, despite its toxic nature. In plants it has been seen to control stomatal apertures, so altering the ability of bacteria to invade plant tissues. Bacteria are known to generate H2S as well as being exposed to plant-generated H2S. During their interaction with plants pathogenic bacteria are known to undergo alterations to their genomic complement. For example Pseudomonas syringae pv. phaseolicola (Pph) strain 1302A undergoes loss of a section of DNA known as a genomic island (PPHGI-1) when exposed to the plants resistance response. Loss of PPHGI-1 from Pph 1302A enables the pathogen to overcome the plants resistance response and cause disease. Here, with the use of H2S donor molecules, changes induced in Pph 1302A genome, as demonstrated by excision of PPHGI-1, were investigated. Pph 1302A cells were found to be resistant to low concentrations of H2S. However, at sub-lethal H2S concentrations an increase in the expression of the PPHGI-1 encoded integrase gene (xerC), which is responsible for island excision, and a subsequent increase in the presence of the circular form of PPHGI-1 were detected. This suggests that H2S is able to initiate excision of PPHGI-1 from the Pph genome. Therefore, H2S that may emanate from the plant has an effect on the genome structure of invading bacteria and their ability to cause disease in plants. Modulation of such plant signals may be a way to increase plant defence responses for crops in the future
Effects of Pseudomonas fluorescens Seed Bioinoculation on Heavy Metal Accumulation for Mirabilis jalapa Phytoextraction in Smelter-Contaminated Soil
Transcriptome profiling of lentil (Lens culinaris) through the first 24 hours of Ascochyta lentis infection reveals key defence response genes
The contractual relationships in the Italian durum wheat chain: Empirical survey evidence
The paper investigates the vertical relations along the Italian durum wheat chain and the factors affecting farmers’ behavior in adopting contractual agreements. Sale/crop-growing contracts in the durum wheat sector are analyzed through a direct survey to a sample of 261 durum wheat farmers. The questionnaire collected data on downstream relations and contract terms between farmers and processing and/or marketing firms along the durum wheat chain. A logit model is used to identify factors affecting the likelihood of contract farming between farms and processors. One of the main issues emerging is the low frequency of written contractual forms between durum wheat farmers and downstream operators. In most cases the farmers do not want constraints and reveal a lack of trust in contracts. They prefer to sell their product to a local downstream operator with whom they have a long-standing and solid relationship of trust. Moreo-ver, results of a logistic model show that certain farm features, such as turnover and degree of specializa-tion in durum wheat production, play an important role in driving the decision to adopt written contracts
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