The host response to COVID-19 pathophysiology over the first few days of infection remains largely unclear, especially the mechanisms in the blood compartment. We report on a longitudinal proteomic analysis of acute-phase COVID-19 patients, for which we used blood plasma, multiple reaction monitoring with internal standards, and data-independent acquisition. We measured samples on admission for 49 patients, of which 21 had additional samples on days 2, 4, 7, and 14 after admission. We also measured 30 externally obtained samples from healthy individuals for comparison at baseline. The 31 proteins differentiated in abundance between acute COVID-19 patients and healthy controls belonged to acute inflammatory response, complement activation, regulation of inflammatory response, and regulation of protein activation cascade. The longitudinal analysis showed distinct profiles revealing increased levels of multiple lipid-associated functions, a rapid decrease followed by recovery for complement activation, humoral immune response, and acute inflammatory response-related proteins, and level fluctuation in the regulation of smooth muscle cell proliferation, secretory mechanisms, and platelet degranulation. Three proteins were differentiated between survivors and nonsurvivors. Finally, increased levels of fructose–bisphosphate aldolase B were determined in patients with exposure to angiotensin receptor blockers versus decreased levels in those exposed to angiotensin-converting enzyme inhibitors. Data are available via ProteomeXchange PXD029437.
Cyclic-di-AMP (c-di-AMP) is a newly discovered secondary messenger molecule that plays a critical role in monitoring several important cellular processes, especially in several Gram-positive bacteria signal transduction pathways. In this study, we seek to unravel the physiological significance of the molecule c-di-AMP in Mycobacterium smegmatis under different conditions, using strains with altered c-di-AMP levels: c-di-AMP null mutant (ΔdisA) and a c-di-AMP over-expression mutant (Δpde). Our thorough analysis of the mutants revealed that the intracellular concentration of c-di-AMP could determine many basic phenotypes such as colony architecture, cell shape, cell size, membrane permeability etc. Additionally, it was shown to play a significant role in multiple stress adaptation pathways in the case of different DNA and membrane stresses. Our study also revealed how the biofilm phenotype of M. smegmatis cells are dependent on intracellular c-di-AMP concentration. Next, we checked how c-di-AMP contributes to antibiotic tolerance characteristics of M. smegmatis, which was followed by a detailed transcriptome profile analysis to reveal key genes and pathways regulated by c-di-AMP in mycobacteria.
In this study, we probe the role of secondary messenger c-di-AMP in drug tolerance, which includes both persister and resistant mutant characterization of Mycobacterium smegmatis. Specifically, with the use of c-di-AMP null and overproducing mutants, we showed how c-di-AMP plays a significant role in resistance mutagenesis against antibiotics with different mechanisms of action. We elucidated the specific molecular mechanism linking the elevated intracellular c-di-AMP level and high mutant generation and highlighted the significance of non-homology-based DNA repair. Further investigation enabled us to identify the unique mutational landscape of target and non-target mutation categories linked to intracellular c-di-AMP levels. Overall fitness cost of unique target mutations was estimated in different strain backgrounds, and then we showed the critical role of c-di-AMP in driving epistatic interactions between resistance genes, resulting in the evolution of multi-drug tolerance. Finally, we identified the role of c-di-AMP in persister cells regrowth and mutant enrichment upon cessation of antibiotic treatment.
The current nightmare for the whole world is COVID-19. The occurrence of concentrated pneumonia cases in Wuhan city, Hubei province of China, was first reported on December 30, 2019. SARS-CoV first disclosed in 2002 but had not outspread worldwide. After 18 years, in 2020, it reemerged and outspread worldwide as SARS-CoV-2 (COVID-19), as the most dangerous virus-creating disease in the world. Is it possible to create a favorable evolution within the short time (18 years)? If possible, then what are those properties or factors that are changed in SARS-CoV-2 to make it undefeated? What are the fundamental differences between SARS-CoV-2 and SARS? The study is one of the initiatives to find out all those queries. Here, four types of protein sequences from SARS-CoV-2 and SARS were retrieved from the database to study their physicochemical and structural properties. Results showed that charged residues are playing a pivotal role in SARS-CoV-2 evolution and contribute to the helix stabilization. The formation of the cyclic salt bridge and other intra-protein interactions specially network aromatic–aromatic interaction also play the crucial role in SAS-CoV-2. This comparative study will help to understand the evolution from SARS to SARS-CoV-2 and helpful in protein engineering.
The current nightmare for the whole world is COVID-19. The occurrence of concentrated pneumonia cases in Wuhan city, Hubei province of China was first reported on December 30, 2019. SARS-CoV first discloses in 2002, but not outspread worldwide. After 18 years, in 2020, it reemerges and outspread worldwide as SARS-CoV-2 (COVID 19), as the most treacherous virus creating disease in the world. Is it possible to create a favorable evolution within this (18 years) short time? If possible, then what are those properties or factors that are changed in SARS-CoV-2 to make it undefeated? What are the fundamental differences between SARS-CoV-2 and SARS? This study will find all those queries. Here, we took 4 types of protein sequences from SARS-CoV-2 and SARS are retrieved from the database to check their physicochemical and structural properties. Results showed that charged residues are playing a pivotal role in SARS-CoV-2 evolution. Those charged residues also contribute to helix stabilization of SARS-CoV-2. Formation of cyclic salt bridge and other intra-protein interactions also play crucial role in SAS-CoV-2. This comparative study will help to understand the evolution from SARS to SARS-CoV-2 and also helps in protein engineering.
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