Biology subjects

Conde, R.

Publications and source records attributed to Conde, R..

3 recordsLinked to original sources

bioRxiv2024

A lipid transport Mla Pqi Chimeric system is essential for Brucella abortus survival in macrophages

The envelope of diderm bacteria comprises of an inner membrane (IM) and an outer membrane (OM). Several pathways have been recently identified that facilitate the transport of phospholipids between the two membranes in Escherichia coli, including maintaining OM lipid asymmetry (Mla) and paraquat inducible (Pqi) systems. In this study, we report the identification and the characterization of a complex named Mpc in the intracellular pathogen Brucella abortus. Mpc is conserved in numerous species of Hyphomicrobiales and exhibits homology to both the Mla and Pqi systems. Mpc is essential for bacterial growth under conditions of envelope stress and for survival within macrophages during the early stages of infection. Analyses of protein-protein interactions and structural predictions indicate that the Mpc complex bridges IM to OM. The absence of this system results in an altered lipid composition of the OM vesicles, supporting the fact that Mpc plays a role in the transport of lipids between membranes. The discovery of a novel lipid trafficking system enhances the diversity and complexity of known lipid trafficking systems within diderm bacteria.

microbiology↗

bioRxiv2021

Aedes aegypti Aag-2 culture cells enter endoreplication process upon pathogen challenge

Metamorphic insects apparently rely on a finite number of cells after emergence to counterbalance either commensal and pathogen presence. For hematophagous insects, blood-feeding is a crucial step for offspring development, therefore enteric cells repairing molecular mechanisms consists in fine regulated pathways to counterattack biotic and abiotic insults. Nevertheless, recent research suggests that midgut cells are capable to adapt their immune responses to pathogen challenges. Recently, Anopheles and Aedes mosquitoes have been observed to increase their DNA cell content upon encounter with parasites, bacteria and virus respectively. Genomic endoreplication is one of the most important processes in larval development for fast transcriptional activity and protein secretion. So, in this paper we explore the ability of Aedes aegypti Aag-2 culture cells to develop a likely endoreplication process to face pathogen presence. Aag-2 cells at 6 and 12 hours post-biotic insult enter a proliferation arrest and increases DNA content, these two phenomena recovers control levels at 24 h post-treatment. It requires more research data about the type of genomic regions that has been replicated in the process, and the concentration that antimicrobial molecules are released into culture media.

immunology↗

bioRxiv2019

New Genotype Emergence of DENV are Constrained by the Double Host Selection, Reducing the Probability of Alternative Serotype Emergence

Since their discovery and sequencing 40 years ago, the DENV genotypes have shown an extreme coherence regarding the serotype class they code for. Considering the RNA virus mutation rate, we used Timed Markov Model to explore the transmission possibilities of mutated viruses and the statistical eventualities of new serotype emergence. We find that around 1 000 years are required for a new serotype to emerge, in line with phylogenetic analysis of the Dengue serotypes. Our work provides a mechanistic explanation of the strictness and low probability of a new Dengue virus serotype occurrence.\n\nAuthor summaryRecent Dengue virus global spread has drawn the attention of the Public Health Policy makers in developing countries and developed countries as well. The infection gravity and the hemorrhagic dengue syndromes have been related with the absence or presence of previous DENV immunity. Therefore, the emergence of a new DENV serotype and its spread constitute a matter of concern. Here, we constructed a mathematical model to determine the probability of such event, as well as de-entangle the mechanistic reasons behind the low serotype emergence factor of the DENV.

evolutionary biology↗