ABSTRACT
In this work, a geological sample of great astrobiological interest was studied through analytical techniques that are currently operating in situ on Mars and others that will operate in the near future. The sample analyzed consisted of an oncoid, which is a type of microbialite, collected in the Salar Carachi Pampa, Argentina. The main peculiarity of microbialites is that they are organo-sedimentary deposits formed by the in situ fixation and precipitation of calcium carbonate due to the growth and metabolic activities of microorganisms. For this reason, the Carachi Pampa oncoid was selected as a Martian analog for astrobiogeochemistry study. In this sense, the sample was characterized by means of the PIXL-like, SuperCam-like and SHERLOC-like instruments, which represent instruments on board the NASA Perseverance rover, and by means of RLS-like and MOMA-like instruments, which represent instruments on board the future ESA Rosalind Franklin rover. It was possible to verify that the most important conclusions and discoveries have been obtained from the combination of the results. Likewise, it was also shown that Perseverance rover-like remote-sensing instruments allowed a first detailed characterization of the biogeochemistry of the Martian surface. With this first characterization, areas of interest for in-depth analysis with Rosalind Franklin-like instruments could be identified. Therefore, from a first remote-sensing elemental identification (PIXL-like instrument), followed by a remote-sensing molecular characterization (SuperCam and SHERLOC-like instruments) and ending with an in-depth microscopic analysis (RLS and MOMA-like instruments), a wide variety of compounds were found. On the one hand, the expected minerals were carbonates, such as aragonite, calcite and high-magnesium calcite. On the other hand, unexpected compounds consisted of minerals related to the Martian/terrestrial surface (feldspars, pyroxenes, hematite) and organic compounds related to the past biological activity related to the oncoid (kerogen, lipid biomarkers and carotenes). Considering samples resembling microbialites have already been found on Mars and that one of the main objectives of the missions is to identify traces of past life, the study of microbialites is a potential way to find biosignatures protected from the inhospitable Martian environment. In addition, it should be noted that in this work, further conclusions have been obtained through the study of the results as a whole, which could also be carried out on Mars.
ABSTRACT
OBJECTIVE: Oral and dental problems are common among human immunodeficiency virus (HIV) infected individuals, particularly the periodontitis is common in HIV-infected subjects. AIM: To evaluate the cytokine patterns in HIV+ patients with periodontitis. MATERIAL AND METHODS: In this study we analysed: HIV+ patients with and without periodontitis and HIV negative patients with and without periodontitis. The clinical periodontal evaluation was based on periodontal disease index and radiographic and clinical evidence of alveolar bone loss. The CD4- and CD8-T cell counts and the plasma viral load were measured. The Interferon (IFN)-gamma, Tumor Necrosis Factor (TNF)-alpha, Interleukin (IL)-2, IL-4, IL-10 and IL-6 were evaluated by Cytometric Bead Array Assay and the IL-18 plasmatic levels were calculated by ELISA. RESULTS: The group of HIV+ with periodontitis shown levels of IL-2 and IL-18 statistically higher that the group of HIV+ without periodontitis. A positive correlation between the degree of the periodontitis and IFN-gamma, IL-2, IL-18 and CD8+ cells in the group of HIV+ with periodontitis has been shown. CONCLUSIONS: The results of the present study confirm that the IL-18, together with other cytokines, has a potential role in aetiopathogenesis of periodontitis in HIV+ patients.