Physical interactions between marine phytoplankton and PET plastics in seawater.

Plastics are the most abundant marine debris globally dispersed in the oceans and its production is rising with documented negative impacts in marine ecosystems. However, the chemical-physical and biological interactions occurring between plastic and planktonic communities of different types of microorganisms are poorly understood. In these respects, it is of paramount importance to understand, on a molecular level on the surface, what happens to plastic fragments when dispersed in the ocean and directly interacting with phytoplankton assemblages. This study presents a computer-aided analysis of electron paramagnetic resonance (EPR) spectra of selected spin probes able to enter the phyoplanktonic cell interface and interact with the plastic surface. Two different marine phytoplankton species were analyzed, such as the diatom Skeletonema marinoi and dinoflagellate Lingulodinium polyedrum, in absence and presence of polyethylene terephthalate (PET) fragments in synthetic seawater (ASPM), in order to insitu characterize the interactions occurring between the microalgal cells and plastic surfaces. The analysis was performed at increasing incubation times. The cellular growth and adhesion rates of microalgae in batch culture medium and on the plastic fragments were also evaluated. The data agreed with the EPR results, which showed a significant difference in terms of surface properties between the diatom and dinoflagellate species. Low-polar interactions of lipid aggregates with the plastic surface sites were mainly responsible for the cell-plastic adhesion by S. marinoi, which is exponentially growing on the plastic surface over the incubation time

The role of molecular genetics in diagnosing familial hematuria(s)

Familial microscopic hematuria (MH) of glomerular origin represents a heterogeneous group of monogenic conditions involving several genes, some of which remain unknown. Recent advances have increased our understanding and our ability to use molecular genetics for diagnosing such patients, enabling us to study their clinical characteristics over time. Three collagen IV genes, COL4A3, COL4A4, and COL4A5 explain the autosomal and X-linked forms of Alport syndrome (AS), and a subset of thin basement membrane nephropathy (TBMN). A number of X-linked AS patients follow a milder course reminiscent of that of patients with heterozygous COL4A3/COL4A4 mutations and TBMN, while at the same time a significant subset of patients with TBMN and familial MH progress to chronic kidney disease (CKD) or end-stage kidney disease (ESKD). A mutation in CFHR5, a member of the complement factor H family of genes that regulate complement activation, was recently shown to cause isolated C3 glomerulopathy, presenting with MH in childhood and demonstrating a significant risk for CKD/ESKD after 40 years old. Through these results molecular genetics emerges as a powerful tool for a definite diagnosis when all the above conditions enter the differential diagnosis, while in many at-risk related family members, a molecular diagnosis may obviate the need for another renal biopsy

Giant mesenteric cyst of mesothelial origin in a haemodialysis patient with previous peritoneal dialysis therapy

n/

Implementing a geochemical, hydrogeological and microbiological monitoring strategy for an open-loop low-temperature geothermal system in a shallow coastal aquifer

Open-loop Ground Water Heat Exchangers (GWHEs) coupled with heat pumps are a common type of domestic and industrial air conditioning system. These systems consist of extracting groundwater which is used to exchange heat with the geothermal heat pump, before being usually re-injected into the aquifer. This operation can affect, albeit usually mildly, the thermal and chemical features of the groundwater and the local ecology. The impacts vary depending on the physico-chemical characteristics of the water, local geology, hydraulic conductivity, and the water volumes extracted and discharged by the GWHE. The purpose of this study is to implement a monitoring plan for an open-loop low-temperature geothermal system located in the Fano Municipality (Central Italy). The urban area lies on the Metauro river alluvial plain, which mostly consists of gravel, sand and silty-clay, with intercalated lenses of sand and clay. These deposits host a phreatic aquifer that can reach a maximum thickness of about 40 m, and whose temperature is generally comprised between 15 and 17°C. Water sampling will be carried out for at least one hydrological year on the injection and extraction wells of the geothermal system and on two wells located up- and down-hydrogeological flow of the selected GWHE. Changes in pressure and groundwater temperature may cause variations of solubility of minerals, redox processes, and sorption-desorption of dissolved components, besides the formation of carbonate and silica mineral scaling. These possible alterations of the natural state of the aquifer will likely be constrained through a monthly-based monitoring that will be aim at the evaluations of the: i) main physico-chemical parameters (i.e., temperature, pH, electrical conductivity, redox potential, and dissolved oxygen content), ii) piezometric levels, and iii) main dissolved ions concentrations (i.e., HCO3, SO4, Cl, NO3, Br, Ca, Mg, Na, K). These measurements will be coupled by bimonthly analysis of selected trace elements concentrations (e.g., Al, Cd, Fe, Mn, Si). In addition, as the modifications of the thermal state of the groundwater might enhance the proliferation of microbial community such as the mesophilic bacteria which start to appear at about 20°C, the dynamics within the aquifer in terms of microbiology will be also evaluated. This study will help to understand possible criticisms for the installation of GWHEs and will provide a support for the definition of a regulatory framework, often lacking at local level to enhance a sustainable use and management of this type of renewable in a fragile environment like that of the groundwaters

Silicification process in diatom algae using different silicon chemical sources: Colloidal silicic acid interactions at cell surface.

The silicon transport and use inside cells are key processes for understanding how diatoms metabolize this element in the silica biogenic cycle in the ocean. A spin-probe electron paramagnetic resonance (EPR) study over time helped to investigate the interacting properties and the internalization mechanisms of silicic acid from different silicon sources into the cells. Diatom cells were grown in media containing biogenic amorphous substrates, such as diatomaceous earth and sponge spicules, and crystalline sodium metasilicate. It was found that the amorphous biogenic silicon slowed down the internalization process probably due to formation of colloidal particles at the cell surface after silicic acid condensation. Weaker interactions occurred with sponge spicules silicon source if compared to the other sources. The EPR results were explained by analyzing transcript level changes of silicon transporters (SITs) and silaffins (SILs) in synchronized Thalassiosira pseudonana cultures over time. The results indicated that the transport role of SITs is minor for silicic acid from both biogenic and crystalline substrates, and the role of SIT3 is linked to the transport of silicon inside the cells, mainly in the presence of sponge spicules. SIL3 transcripts were expressed in the presence of all silicon sources, while SIL1 transcripts only with sponge spicules. The data suggest that the transport of silicic acid from various silicon sources in diatoms is based on different physico-chemical interactions with the cell surface

Spin Probe Analysis of Microtubules Structure and Formation

Microtubules (MTs) control cell replication, material transport and motion in eukaryotic cells, but MT role in several pathologies is still unknown. These functions are related to the MT physico-chemical properties and MT formation mode starting from tubulin molecules. This study describes a new method, based on the computer aided analysis of the electron paramagnetic resonance (EPR) spectra of selected spin probes to obtain structural and dynamical information on tubulins and MTs and the kinetics of MTs formation promoted by guanosine-50-triphosphate (GTP). It was found that tubulin and MTs avoid radical quenching caused by ethylene glycol tetraacetic acid (EGTA). MT formation showed different kinetics as a function of tubulin concentration. At 5 mg/mL of tubulin, MTs were formed in 8 min. These results are also useful for getting information on MT–drug interactions