Survival of a sars-cov-2 surrogate on flow-pack polyethylene and polystyrene food trays at refrigeration and room temperature conditions

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of the current pandemic referred to as coronavirus disease 2019, is spread by direct and indirect transmission between humans, including contact with contaminated surfaces, frozen food, packaging materials, and storage environments. Food contamination may occur in the “farm-to-table” lifecycle through contact with food handlers and environments. In the present study, the survival of a SARS-CoV-2 surrogate (feline coronavirus (FCoV)) at room temperature and refrigeration conditions for different time intervals on two types packaging widely used packaging, namely flow-pack polyethylene and polystyrene food trays, was investigated. FCoV was stable on the flow-pack polyethylene for 48 h and 120 h at room temperature and 4◦C, respectively, while it persisted on polystyrene food trays for 36 h at room temperature and for 120 h at +4◦C. The results of our study highlight the possible implications of food packaging in the spread of SARS-CoV-2 during the current pandemic

Coexistence of Native-like and Non-Native Partially Unfolded Ferricytochrome <i>c</i> on the Surface of Cardiolipin-Containing Liposomes

Cytochrome <i>c</i>, in spite of adopting a rather rigid structure around its prosthetic heme group, is rather diverse with regard to its function and structural variability. On the surface of the inner membrane of mitochondria it serves as an electron transfer carrier. However, at conditions which have not yet been unambiguously identified, cytochrome <i>c</i> can adopt a variety of non-native conformations, some of which exhibit peroxidase activity. Cardiolipin-containing liposomes have served as ideal model system to investigate the various modes of interaction between cytochrome <i>c</i> and the inner mitochrondrial membrane. We probed the binding of horse heart ferricytochrome <i>c</i> to liposomes formed with 20% tetraoleoyl cardiolipin (TOCL) and 80% dioleoyl-<i>sn</i>-glycero-3-phosphocholine (DOPC) as a function of lipid/protein ratio by fluorescence and visible circular dichroism spectroscopy. The obtained binding isotherms suggest that they reflect reversible binding processes, which excludes the possibility of significant protein insertion into the membrane. A global analysis of our data revealed the existence of two binding sites on the protein which causes rather different degrees of protein unfolding. We found that these two modes of interaction between protein and liposome led to conformational changes. While site 1 is relatively unaffected by NaCl, site 2 shows a more native-like state or a higher population of the native state in the presence of NaCl. At the highest utilized concentration of NaCl, there is only a 40% inhibition of the binding to site 2. We interpret our finding for this binding site as reflecting an equilibrium between electrostatically bound proteins with a high degree of unfolding and less unfolded proteins which bind either via H-bonding between lysine side chains and PO₂^– or hydrophobic interactions. With regard to site 2 binding, our results are reminiscent of the two-state equilibrium between a compact C and an extended E-state proposed by Pletneva and co-workers (Hanske et al. <i>Proc. Natl. Acad. Sci. U.S.A.</i> <b>2012</b>, <i>109</i>, 125–230). We conjecture that the nonelectrostatically bound proteins should have higher abilities to maintain the redox potential that is required for the function as an electron transfer protein

Coexistence of Native-Like and Non-Native Cytochrome <i>c</i> on Anionic Liposomes with Different Cardiolipin Content

We employed a combination of fluorescence, visible circular dichroism, and absorption spectroscopy to study the conformational changes of ferricytochrome <i>c</i> upon its binding to cardiolipin-containing small unilamellar vesicles. The measurements were performed as a function of the cardiolipin concentration, the cardiolipin content of the liposomes, and the NaCl concentration of the solvent. The data were analyzed with a novel model that combines a single binding step with a conformational equilibrium between native-like and non-native-like proteins bound to the membrane surface. The equilibrium between the two conformations, which themselves are comprised of structurally slightly different subconformations, shifts to the more non-native-like conformation with increasing cardiolipin concentration. For the binding isotherms described in this paper, we explicitly considered the enthalpic and entropic contributions of molecular crowding to protein binding at low lipid concentrations and high occupancy of the liposome surface. Increasing the CL content of liposomes increases the overall binding affinity but makes the conformational distribution much more susceptible to the influence of sodium and chloride ions, which shifts the equilibrium toward the more native-like state and directly inhibits binding, particularly to liposomes with 100% cardiolipin content. Spectroscopic evidence further suggests that a fraction of the non-native conformers adopts a pentacoordinated state similar to those obtained in class C peroxidases. On the basis of our results, we propose a hypothesis that describes the balance between facilitating and impeding forces controlling the peroxidase activity of cytochrome <i>c</i> in the inner membrane space of mitochondria

The (Not Completely Irreversible) Population of a Misfolded State of Cytochrome <i>c</i> under Folding Conditions

This paper reports the discovery of a (meta)­stable partially unfolded state of horse heart ferricytochrome <i>c</i> that was obtained after exposing the protein to a solution with an alkaline pH of 11.5 for 1 week. Thereafter, the protein did not undergo any detectable change in its secondary and tertiary structure upon adjusting the solution to folding promoting conditions at neutral pH. Spectroscopic data suggest that the misfolded protein exhibits a hexacoordinated low-spin state with a hydroxyl ion as the likely ligand. Below pH 6, a new ligation state emerges with the spectroscopic characteristics of a pentacoordinated quantum mixed state of the heme iron. Gel electrophoresis revealed substantial formation of soluble dimers and trimers at submillimolar concentrations, whereas monomers were dominant at lower, micromolar concentrations. Ultraviolet circular dichroism spectra indicate that oxidized monomers are pre-molten globule to globule-like with a substantial fraction of secondary (helical) structure reminiscent of alkaline state V. The oligomers contain even more helical structure, which suggests domain swapping as the underlying mechanism of their formation. A substantial fraction of the submillimolar mixture of monomers and oligomers underwent a reduction of the heme iron. Its dependence on pH suggests the coupling to a proton transfer process. Altogether, our data indicate a partially unfolded ferricytochrome <i>c</i> conformation with spectroscopic characteristics reminiscent of the recently discovered alkaline isomer V_b, which is stabilized under folding conditions by exposing the protein to a very alkaline pH for an extended period of time

PRIMI: Pilot Project on Marine oil pollution

The Pilot Project PRIMI, one of the seven initiatives started by the Italian Space Agency (ASI) to support risk management activities, aims to provide information on oil marine pollution. The system, presently at half of its development cycle, consists of four components, two of them devoted to the analysis of SAR and Optical satellite images for the detection of slicks, an oil spill forecast subsystem and a central archive that provides Web-GIS services. A preliminary version of the system is already operational, while the final version will be ready by the end of 2009. Besides the slicks relevant information, the system is foreseen to provide also the meteorological and oceanographic information and the detected ships present on the scenes analysed. The architecture of the system, the operational scenario and the preliminary results are presented

Evaluation of the persistence of SARS-CoV-2 (ATCC® VR-1986HKTM) on two different food contact materials: flow pack polyethylene and polystyrene food trays

Even though SARS-CoV-2's primary transmission pathway is person-to-person, the role played by surfaces and food contact materials in carrying viral RNA should be further explored. For this purpose, the study aimed to investigate the persistence of SARS-CoV-2 using the strain ATCC® VR-1986HKTM on flow pack polyethylene (FPP) and polystyrene food trays (PFT). Samples of FPP and PFT were contaminated with heat-inactivated SARS-CoV-2 and were incubated at a temperature of 24 ± 1 °C and at controlled relative humidity (RH 65%). The experimental design included analyses at the time 0, 3, 6, 12, 24, 36, 48 and after every 24 h until the viral RNA was no longer detectable. The results showed a significant decrease (P &lt; 0.001) in viral copy numbers on PFT within 3 h (24% reduction) and, at 72 h, the viral RNA had fallen below the limit of detection. Regarding the FPP, it was necessary to wait 24 h for a significant decrease (P = 0.015) in the viral load (14% reduction), while the detection threshold was reached at 96 h. These findings showed that the viral RNA persists longer on flow pack polyethylene samples than on polystyrene food trays, thus highlighting the importance of material characteristics in the persistence of SARS-CoV-2

Cosmo-Skymed contribution in oil spill monitoring of the Mediterranean Sea

High resolution Cosmo-SkyMed SAR images are used for oil spill detection and ship identification on the Mediterranean Sea, in the framework of PRIMI Pilot Project currently developed by Italian Space Agency (ASI). The system consists of four components, two of them devoted to the analysis of the SAR and Optical satellites images for the slicks detection, an oil spill forecast subsystem and a central archive that provides web-gis services; a preliminary version of the system is already operational. Besides the slicks relevant information and detected ships on the analyzed scene, the system also provides meteorological and oceanographic information. The architecture of the system, the operational scenario and the preliminary results are presented