Effects of long term application of compost and poultry manure on soil quality of citrus orchards in Southern Italy.

A six-year study was carried out in an organically managed orange orchard located in Sicily (Southern Italy) to assess the effect of compost and organic fertilizers utilisation on soil quality. Adopting a randomized-block experimental design with three replicates, four treatments were carried out. In treatments 1 and 2, two different composts (C1 from distillery by products and C2 from livestock wastes) were applied. The plots of treatment 3 were fertilized using dried poultry manure. The control treatment was fertilized with mineral/synthetic fertilizers. In order to verify the hypothesis that composts and organic fertilizers improve soil fertility, soil quality was evaluated by selecting dynamic soil parameters, as indicators linked to C and N cycles. Total organic C, total N, C/N ratio, humified fraction, isoelectric focusing (IEF) of extracted organic matter, microbial biomass C, potentially mineralisable N under anaerobic conditions, potenzially mineralizable C, C mineralization quotient and metabolic quotient were determined for each sample. Furthermore, the Comunity level Physiological Profile (by Biolog tecnique) was defined, calculating derived functional biodiversity and versatility indexes. Parameters related to IEF and potentially mineralizable C showed significant differences among the treatments. Moreover, total C, total N and humification parameters tended to increase, while no differences were observed in biodiversity indexes. On these findings, it was concluded that composts and poultry manure only weakly affected soil properties, though they increased soil nutritive elements potentially available to crops

Mixed nodule infection in Sinorhizobium meliloti-medicago sativa symbiosis suggest the presence of cheating behavior

In the symbiosis between rhizobia and legumes, host plants can forms ymbiotic root nodules with multiple rhizobial strains, potentially showing different symbiotic performances in nitrogen fixation. Here, we investigated the presence of mixed nodules, containing rhizobia with different degrees of mutualisms, and evaluate their relative fitness in the Sinorhizobium meliloti-Medicago sativa model symbiosis. We used three S. meliloti strains, the mutualist strains Rm1021 and BL225C and the non-mutualist AK83. We performed competition experiments involving both in vitro and in vivo symbiotic assays with M. sativa host plants. We show the occurrence of a high number (from 27 to 100%) of mixed nodules with no negative effect on both nitrogen fixation and plant growth. The estimation of the relative fitness as non-mutualist/mutualist ratios in single nodules shows that in some nodules the non-mutualist strain efficiently colonized root nodules along with the mutualist ones. In conclusion, we can support the hypothesis that in S. meliloti-M. sativa symbiosis mixed nodules are formed and allow non-mutualist or less-mutualist bacterial partners to be less or not sanctioned by the host plant, hence allowing a potential form of cheating behavior to be present in the nitrogen fixing symbiosis

Exploring the Bacterial Communities of Infernaccio Waterfalls: A Phenotypic and Molecular Characterization of Acinetobacter and Pseudomonas Strains Living in a Red Epilithic Biofilm

Acquarossa river (Viterbo, Italy) was the site of a prospering Etruscan civilization thanks to metallurgical activity around 625-550 B.C. This caused the spread of heavy metals throughout the area. Rocks along the river probably act as a filter for these elements and they are covered by two different biofilms (epilithons). They differ for both color and bacterial composition. One is red and is enriched with Pseudomonas strains, while the other one is black and Acinetobacter is the most represented genus. Along the river lay the Infernaccio waterfalls, whose surrounding rocks are covered only by the red epilithon. The bacterial composition of this biofilm was analyzed through high throughput sequencing and compared to those ones of red and black epilithons of Acquarossa river. Moreover, cultivable bacteria were isolated and their phenotype (i.e., resistance against antibiotics and heavy metals) was studied. As previously observed in the case of Acquarossa river, characterization of bacterial composition of the Infernaccio red epilithon revealed that the two most represented genera were Acinetobacter and Pseudomonas. Nonetheless, these strains differed from those isolated from Acquarossa, as revealed by RAPD analysis. This work, besides increasing knowledge about the ecological properties of this site, allowed to isolate new bacterial strains, which could potentially be exploited for biotechnological applications, because of their resistance against environmental pollutants

Arable plant communities as a surrogate of crop rhizosphere microbiota

Soil microbiota is a crucial component of agroecosystem biodiversity, enhancing plant growth and providing impor-tant services in agriculture. However, its characterization is demanding and relatively expensive. In this study, we eval-uated whether arable plant communities can be used as a surrogate of bacterial and fungal communities of therhizosphere of Elephant Garlic (Allium ampeloprasum L.), a traditional crop plant of central Italy. We sampled plant,bacterial, and fungal communities, i.e., the groups of such organisms co-existing in space and time, in 24 plots locatedin eight fields and four farms. At the plot level, no correlations in species richness emerged, while the composition ofplant communities was correlated with that of both bacterial and fungal communities. As regards plants and bacteria,such correlation was mainly driven by similar responses to geographic and environmental factors, while fungal com-munities seemed to be correlated in species composition with both plants and bacteria due to biotic interactions. Allthe correlations in species composition were unaffected by the number of fertilizer and herbicide applications,i.e., agricultural intensity. Besides correlations, we detected a predictive relationship of plant community compositiontowards fungal community composition. Our results highlight the potential of arable plant communities to be used as asurrogate of crop rhizosphere microbial communities in agroecosystems

Permanent draft genome sequences of the symbiotic nitrogen fixing Ensifer meliloti strains BO21CC and AK58

Ensifer (syn. Sinorhizobium) meliloti is an important symbiotic bacterial species that fixes nitrogen. Strains BO21CC and AK58 were previously investigated for their substrate utilization and their plant-growth promoting abilities showing interesting features. Here, we describe the complete genome sequence and annotation of these strains. BO21CC and AK58 genomes are 6,985,065 and 6,974,333 bp long with 6,746 and 6,992 genes predicted, respectively. © retained by original authors

Accumulation of neutral lipids in peripheral blood mononuclear cells as a distinctive trait of Alzheimer patients and asymptomatic subjects at risk of disease

<p>Abstract</p> <p>Background</p> <p>Alzheimer's disease is the most common progressive neurodegenerative disease. In recent years, numerous progresses in the discovery of novel Alzheimer's disease molecular biomarkers in brain as well as in biological fluids have been made. Among them, those involving lipid metabolism are emerging as potential candidates. In particular, an accumulation of neutral lipids was recently found by us in skin fibroblasts from Alzheimer's disease patients. Therefore, with the aim to assess whether peripheral alterations in cholesterol homeostasis might be relevant in Alzheimer's disease development and progression, in the present study we analyzed lipid metabolism in plasma and peripheral blood mononuclear cells from Alzheimer's disease patients and from their first-degree relatives.</p> <p>Methods</p> <p>Blood samples were obtained from 93 patients with probable Alzheimer's disease and from 91 of their first-degree relatives. As controls we utilized 57, cognitively normal, over-65 year-old volunteers and 113 blood donors aged 21-66 years, respectively. Data are reported as mean ± standard error. Statistical calculations were performed using the statistical analysis software Origin 8.0 version. Data analysis was done using the Student t-test and the Pearson test.</p> <p>Results</p> <p>Data reported here show high neutral lipid levels and increased ACAT-1 protein in about 85% of peripheral blood mononuclear cells freshly isolated (<it>ex vivo</it>) from patients with probable sporadic Alzheimer's disease compared to about 7% of cognitively normal age-matched controls. A significant reduction in high density lipoprotein-cholesterol levels in plasma from Alzheimer's disease blood samples was also observed. Additionally, correlation analyses reveal a negative correlation between high density lipoprotein-cholesterol and cognitive capacity, as determined by Mini Mental State Examination, as well as between high density lipoprotein-cholesterol and neutral lipid accumulation. We observed great variability in the neutral lipid-peripheral blood mononuclear cells data and in plasma lipid analysis of the subjects enrolled as Alzheimer's disease-first-degree relatives. However, about 30% of them tend to display a peripheral metabolic cholesterol pattern similar to that exhibited by Alzheimer's disease patients.</p> <p>Conclusion</p> <p>We suggest that neutral lipid-peripheral blood mononuclear cells and plasma high density lipoprotein-cholesterol determinations might be of interest to outline a distinctive metabolic profile applying to both Alzheimer's disease patients and asymptomatic subjects at higher risk of disease.</p