Biogeochemical and microbial community structure differently modulates CO2 and CH4 dynamics in two adjacent volcanic lakes (Monticchio, Italy)

By hosting significant amounts of extra-atmospheric dissolved gases, including geogenic CO2 and CH4, volcanic lakes provide relevant ecosystem services through the key role the aquatic microbial community in mediating freshwater carbon fluxes. In view of elucidating the mechanisms governing the microbial spatial distribution and the possible implications for ecosystem functioning, we compared the hydrogeochemical features and the microbial community structure of two adjacent stratified volcanic lakes (Lake Grande - LG and Lake Piccolo - LP). Water chemistry, gases and their isotopic composition were coupled with microbial pigment profiling, cell counting, and phylogenetic analyses. LP showed transparent waters with low concentrations of chlorophyll-a and the occurrence of phycoerytrin-rich cyanobacteria. LG was relatively more eutrophic with a higher occurrence of diatoms and phycocyanine-rich cyanobacteria. Considering the higher concentrations of CO2 and CH4 in bottom waters, the oligotrophic LP was likely a more efficient sink of geogenic CO2 in comparison to the adjacent eutrophic LG. The prokaryotic community was dominated by the mixothrophic hgcI clade (family Sporichthyaceae) in the LG surface waters, while in LP this taxon was dominant down to -15 m. Moreover, in LP, the bottom dark waters harbored a unique strictly anaerobic bacterial assemblage associated with methanogenic Archaea (i.e. Methanomicrobiales), resulting in a high biogenic methane concentration. Water layering and light penetration were confirmed as major factors affecting the microbial distribution patterns. The observed differences in the geochemical and trophic conditions reflected the structure of the aquatic microbial community, with direct consequences on the dynamics of dissolved greenhouse gases

Francesco Orlando, Il soprannaturale letterario. Storia, logica e forme, a cura di Stefano Brugnolo, Luciano Pellegrini, Valentina Sturli

Gli autori discutono intorno al volume di Francesco Orlando, Il soprannaturale letterario. Storia, logica e forme, a cura di Stefano Brugnolo, Luciano Pellegrini, Valentina Sturli

Nutritional status of vines affected with esca proper

A<span class="s3"> </span>vineyard of the cv. Trebbiano d’Abruzzo located in Abruzzo, Italy,<span class="Apple-converted-space">  </span>was monitored for more than ten years to distinguish healthy vines not only from vines with the visual leaf symptoms of esca, but also from those vines that were esca-infected but did not produce any visual symptoms for one or more growing seasons. In the period 2004–2006, leaves and berries were collected at four phenological growth stages from three groups of vines: healthy vines, infected vines showing esca symptoms, and infected vines that did not show symptoms. The macro and micro-elements of the leaves and berries, and the quality parameters of the must were determined. Esca did not seem to affect nutrient uptake in the vines. Nevertheless there were some differences in the nutrient levels of the leaves between healthy and diseased vines consistent with the degradation of the leaf blade caused by esca. Berries from symptomatic vines were less ripe at the time of harvesting and therefore had higher levels of mineral elements. These berries also had higher levels of nitrogen, which are thought to be associated with the defence response of diseased vines to esca, as are higher levels of iron in the leaves of diseased vines. The study confirmed earlier findings that fruit composition did not differ greatly between healthy and diseased-but-asymptomatic vines. In the three-year study period there were differences in the incidence of leaf symptoms and differences in nutrient levels attributable to fertiliser applications and rainfall. These differences suggested that the amount of mineral nutrients affected the onset of esca symptoms: a higher availability of nutrients in a growing season increased the proportion of diseased vines with symptoms and lowered the proportion of diseased vines without symptoms, whereas in a growing season with the lower levels of<span class="Apple-converted-space">  </span>water and potassium, the yield was reduced, but this was accompanied by an increase in the proportion of diseased vines without symptoms. It is suggested that a higher availability of nutrients for diseased vines lowers the resistance of these vines and, by improving the nutrition not only of the vines themselves but also of the esca fungi, increase fungal virulence, as a result of which there is a greater incidence of diseased vines showing leaf symptoms

Effect of Different Foliar Fertilizer Applications on Esca Disease of Grapevine: Symptom Expression and Nutrient Content in the Leaf and Composition of the Berry

Abstract: Esca disease, the most common grapevine wood disease in Europe, causes yield losses correlated with the foliar symptoms’ expression. In two vineyards located in the Abruzzo Region of Italy, each of which were investigated for esca symptoms after 1994, different applications of macro- and microelements were performed in two consecutive growing seasons. The main aim of the work consisted of verifying the effects of the fertilizer applications on the foliar symptoms’ expression, in order to deepen knowledge of the nature of the symptom, which is still unclear. For each treatment, in each year, the leaf content of macro- and microelements and the composition of berries and musts were assessed. The effects of these applications on vegetative growth and yield quantity were also verified. The trials were carried out on symptomatic, asymptomatic and apparently healthy vines. All applications, in particular those with microelements, increased the foliar symptoms’ expression, and a greater vegetative growth was detected only in vines treated with NPK fertilizers. The symptoms’ increase was always associated in the leaf with a decrease of calcium, and to a lesser extent, magnesium, reinforcing the hypothesis of the plant’s hypersensitive reaction in the development of foliar symptoms, given the role of calcium in the defense response. The vineyards were in nutritional balance regardless of the fertilizer applications. The general increase in foliar symptoms and the decrease in sugars in the musts of asymptomatic treated vines underlined the importance of the vegetative-productive balance, in Esca infected vineyards especially, in order to limit the symptoms’ expression and the decrease in yield

Hemoglobin-Conjugated Gelatin Microsphere as a Smart Oxygen Releasing Biomaterial

In this study, a novel micrometric biomaterial acting as a cyclic oxygen releasing system is designed. Human hemoglobin (Hb) is conjugated to the surface of gelatin microspheres (GM) to produce gelatin hemoglobin oxygen depot (G-HbOD). G-HbOD is obtained by means of two different conjugation strategies. The degree of conjugation of GM surfaces in terms of free amino groups by using HPLC is first evaluated. By following the strategy A (G-HbOD_A), Hb is conjugated to GM by means of the formation of a polyurethane linker. In the strategy B (G-HbOD_B) the conjugation occurs via amide bound formation. Physical and morphological differences between G-HbOD_A and G-HbOD_B are investigated by means of Fourier Transform Infrared Spectroscopy (FTIR), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Differences in oxygen uptake/release kinetics are found depending on the conjugation strategy and it is proved that G-HbOD works under repeated cycles in microfluidic chip. Moreover, G-HbOD is also able to work as oxygen depot in the early stages of 3D cell cultures