Macrolide therapy in Pseudomonas aeruginosa infections causes uL4 ribosomal protein mutations leading to high-level resistance.

OBJECTIVES: Pseudomonas aeruginosa colonizes the cystic fibrosis (CF) airways causing chronic bacterial lung infections. CF patients are routinely treated with macrolides, however, P. aeruginosa is considered insusceptible as consequence of inadequate susceptibility testing leaving resistance mechanism completely overlooked. Here, we investigated a new mechanism of macrolide resistance caused by ribosomal protein mutations. METHODS: Investigating a longitudinal collection of 529 isolates from CF patients and analysing 5758 protein sequences from different sources, mutations in P. aeruginosa's ribosomal proteins connected to macrolide resistance were identified. Using a modified susceptibility testing protocol, isolates harbouring a mutated uL4 ribosomal protein were tested for resistance against macrolide antibiotics and macrolide-induced quorum sensing modulation. Proteome and ribosome profiling were applied to assess the impact of the mutations on the bacterial physiology. RESULTS: Five uL4 mutations were identified in isolates from different CF patients. Most mapped to the conserved loop region of uL4 and resulted in increased macrolide tolerance (>10-fold relative to wt strains). Greater concentrations (>10-fold) of macrolide antibiotic were needed to inhibit the growth, reduce swimming motility, and induce redox sensitivity of the uL4 mutants. 16 proteins involved in ribosome adaptation displayed altered expression possibly to compensate for the uL4 mutations, which changed the ribosome stoichiometry without negatively affecting bacterial physiology. CONCLUSIONS: Macrolide antibiotics should, therefore, be considered as active antimicrobial agents against P. aeruginosa and resistance development should be contemplated when patients are treated with prolonged courses of macrolides. Importantly, improved macrolide susceptibility testing is necessary for the detection of resistant bacteria.

Ribosomal proteins as a possible tool for blocking SARS-COV 2 virus replication for a potential prospective treatment.

Coronavirus disease (COVID-19) is caused by SARS-COV2 and has resulted in more than four million cases globally and the death cases exceeded 300,000. Normally, a range of surviving and propagating host factors must be employed for the completion of the infectious process including RPs. Viral protein biosynthesis involves the interaction of numerous RPs with viral mRNA, proteins which are necessary for viruses replication regulation and infection inside the host cells. Most of these interactions are crucial for virus activation and accumulation. However, only small percentage of these proteins is specifically responsible for host cells protection by triggering the immune pathway against virus. This research proposes RPs extracted from bacillus sp. and yeast as new forum for the advancement of antiviral therapy. Hitherto, antiviral therapy with RPs-involving viral infection has not been widely investigated as critical targets. Also, exploring antiviral strategy based on RPs could be a promising guide for more potential therapeutics.

Proteínas Inactivadoras de Ribosomas (RIPs) y sus aplicaciones en la construcción de inmunotoxinas para la terapia experimental del cáncer / Ribosome-Inactivating Proteins (RIPs) and their aplication to the construction of immunotoxins for the experimental cancer therapy

Las proteínas inactivadoras de ribosomas (RIPs) son inhibidoras de la síntesis de proteínas que inactivan a los ribosomas de manera irreversible. Las más conocidas son las RIPs vegetales de las cuales ricina es la más estudiada. El mecanismo de acción consiste en la depurinación del ARNr mayor de los ribosomas (28 S ARNr en el caso de los mamíferos). Las RIPs aceptan también otros substratos tales como ADN, ARN genómico viral y algunos polinucleótidos sintéticos que resultan multidepurinados. Diversas RIPs presentan actividad antiviral contra virus vegetales y animales y actividad topológica sobre el ADN. En nuestro laboratorio hemos descubierto un nuevo tipo de RIP que hemos denominado RIP de tipo 2 no tóxica. Entre estas RIPs cabe destacar nigrina b y nigrina b básica, de Sambucus nigra y ebulina, de Sambucus ebulus. Estas RIPs son entre 1.000 y 10.000 veces menos tóxicas para células cultivadas y ratones que la ricina. La aplicación más notable de las RIPs es la construcción de inmunotoxinas y conjugadospara la terapia experimental en particular la del cáncer humano. Hemos preparado conjugados activos contra las células de cáncer de colon e inmunotoxinas activas contra células CD105+ características de la neovasculatura tumoral (AU)

[The isolation of the ribosomal fraction of Clostridium perfringens type A and an evaluation of its protective activity]. / Poluchenie ribosomal'noi fraktsii Clostridium perfringens tipa A i otsenka ee protektivnoi aktivnosti.

A method for isolation of the ribosomal fraction (RF) from the cytoplasm of type-A C. perfringens strain BP6K was developed and its chemical and antigenic properties characterized. RF has been found to possess protective properties: two subcutaneous immunizations of mice with RF preparations adsorbed on Al(OH)3 in doses of 250 and 500 micrograms (dry weight) has ensured, on the average, the protection of 41.9% of the immunized animals from 1 DCL of type-A C. perfringens strain BP6K culture.