A new ionization method named surface-activated chemical ionization (SACI) has been realized. In this invention a commercially available atmospheric pressure chemical ionization (APCI) chamber, employed without any corona discharge (no-discharge APCI), has been modified with the insertion of a gold surface, leading to a significant improvement in the ionization efficiency. The ionization of the sample takes place by both gas-phase and surface-activated processes. This new ionization source is able to generate ions with high molecular mass and low charge states, leading to improved sensitivity and reduced noise. The new device has been tested in the analysis of some peptides. A comparison between the performance with and without the presence of the surface, and the optimization of the operating conditions (nebulizing gas flow, sample solution flow, pH of solution, and surface area), are reported and discussed.

SARS-CoV-2 has become one of the most studied viruses of the last century. It was assumed that the only possible host for these types of viruses was mammalian eukaryotic cells. Our recent studies show that microorganisms in the human gastrointestinal tract affect the severity of COVID-19 and for the first time provide indications that the virus might replicate in gut bacteria. In order to further support these findings, in the present work, cultures of bacteria from the human microbiome and SARS-CoV-2 were analyzed by electron and fluorescence microscopy. The images presented in this article, in association with the nitrogen (15N) isotope-labeled culture medium experiment, suggest that SARS-CoV-2 could also infect bacteria in the gut microbiota, indicating that SARS-CoV-2 could act as a bacteriophage. Our results add new knowledge to the understanding of the mechanisms of SARS-CoV-2 infection and fill gaps in the study of the interactions between SARS-CoV-2 and non-mammalian cells. These findings could be useful in suggesting specific new pharmacological solutions to support the vaccination campaign.

In previous studies, the production of ions in an APCI source without any corona discharge was observed, and the intensity of the ion signals showed significant increases on placing a metallic surface at 45 degrees inside an orthogonal ion source. This method was named surface-activated chemical ionization (SACI). The present study was performed to investigate the mechanisms of ion production with or without the presence of the metallic surface, by varying instrumental parameters and the geometrical configuration. Approximate calculations show that, in the absence of corona discharge and of any additional surfaces, ions cannot be produced by collisional phenomena, because of their low kinetic energy, in the 10(-2) to 10(-3) eV range. Two alternative possibilities have been considered: the first takes into account that ions may originate by collision of neutral clusters of polar solvent molecules with the APCI source surfaces through clusterelectric effect. The second takes into account that the water dissociation constant k(w) is temperature dependent, passing from 10(-14.1669) at 20 degrees C to 10(-12.4318) at 90 degrees C. It means that the [H(+)] varies from 8.3 x 10(-8) to 6.1 x 10(-7) M going from 20 to 90 degrees C. Hence, at the high temperatures experimented in the APCI vaporizer, H(+) becomes available in solution in molar quantities analogous to those of analyte, and the protonation of the analyte itself can consequently occur. The activation of further ionization processes in the presence of the metallic surface can be reasonably attributed to interactions between gas-phase analyte molecules and solvent molecules adsorbed on the surface. Experiments performed with a thin layer of deuterated glycerol on the surface led to unequivocal results, i.e. the production of [M + D](+) ions of the analyte.

Background Scientific evidence for the involvement of human microbiota in the development of COVID-19 disease has been reported recently. SARS-CoV-2 RNA presence in human faecal samples and SARS-CoV-2 activity in faeces from COVID-19 patients have been observed. Methods Starting from these observations, an experimental design was developed to cultivate in vitro faecal microbiota from infected individuals, to monitor the presence of SARS-CoV-2, and to collect data on the relationship between faecal bacteria and the virus. Results Our results indicate that SARS-CoV-2 replicates in vitro in bacterial growth medium, that the viral replication follows bacterial growth and it is influenced by the administration of specific antibiotics. SARS-CoV-2-related peptides have been detected in 30-day bacterial cultures and characterised. Discussion Our observations are compatible with a ‘bacteriophage-like’ behaviour of SARS-CoV-2, which, to our knowledge has not been observed or described before. These results are unexpected and hint towards a novel hypothesis on the biology of SARS-CoV-2 and on the COVID-19 epidemiology. The discovery of possible new modes of action of SARS-CoV-2 has far-reaching implications for the prevention and the treatment of the disease.