Horizontally acquired AT-rich genes in Escherichia coli cause toxicity by sequestering RNA polymerase

Horizontal gene transfer permits rapid dissemination of genetic elements between individuals in bacterial populations. Transmitted DNA sequences may encode favourable traits. However, if the acquired DNA has an atypical base composition, it can reduce host fitness. Consequently, bacteria have evolved strategies to minimize the harmful effects of foreign genes. Most notably, xenogeneic silencing proteins bind incoming DNA that has a higher AT content than the host genome. An enduring question has been why such sequences are deleterious. Here, we showed that the toxicity of AT-rich DNA in Escherichia coli frequently results from constitutive transcription initiation within the coding regions of genes. Left unchecked, this causes titration of RNA polymerase and a global downshift in host gene expression. Accordingly, a mutation in RNA polymerase that diminished the impact of AT-rich DNA on host fitness reduced transcription from constitutive, but not activator-dependent, promoters

Activity of the ethanolic extract of propolis (EEP) as a potential inhibitor of quorum sensing-mediated pigment production in chromobacterium violaceum and virulence factor production in pseudomonas aeruginosa

Bacteria are capable of the organized expression of specific sets of genes through a recently discovered phenomenon termed quorum sensing (QS). Researchers are beginning to focus their efforts into the discovery of potential QS inhibitors for the development of novel antipathogenic drugs. This study investigated the QS inhibitory potential of the ethanolic extract of propolis (EEP) in the test organism Chromobacterium violaceum ATCC 12472 and the opportunistic organism Pseudomonas aeruginosa PAO1. Results of this study showed EEP as a potential inhibitor of QSmediated violacein production in C. violaceum. EEP was thereby subjected to further testing on its ability to interfere with virulence factor production and biofilm formation in P. aeruginosa. It was found that EEP was able to significantly affect the LasA and LasB protease activities. In addition, changes in the protease activity were observed with no significant effects on the growth of the organism. This implies that changes in the enzyme activities are unrelated to bactericidal consequences. However, it was also found that EEP inhibited the biofilm formation of P. aeruginosa PAO1 at lower concentrations but not at higher concentrations. This suggests the need for further investigations to be made on the effect of EEP on the maturation and differentiation of biofilms

Pediatric Research Observing Trends and Exposures in COVID-19 Timelines (PROTECT): Protocol for a Multisite Longitudinal Cohort Study.

Assessing the real-world effectiveness of COVID-19 vaccines and understanding the incidence and severity of SARS-CoV-2 illness in children are essential to inform policy and guide health care professionals in advising parents and caregivers of children who test positive for SARS-CoV-2. This report describes the objectives and methods for conducting the Pediatric Research Observing Trends and Exposures in COVID-19 Timelines (PROTECT) study. PROTECT is a longitudinal prospective pediatric cohort study designed to estimate SARS-CoV-2 incidence and COVID-19 vaccine effectiveness (VE) against infection among children aged 6 months to 17 years, as well as differences in SARS-CoV-2 infection and vaccine response between children and adolescents. The PROTECT multisite network was initiated in July 2021, which aims to enroll approximately 2305 children across four US locations and collect data over a 2-year surveillance period. The enrollment target was based on prospective power calculations and accounts for expected attrition and nonresponse. Study sites recruit parents and legal guardians of age-eligible children participating in the existing Arizona Healthcare, Emergency Response, and Other Essential Workers Surveillance (HEROES)-Research on the Epidemiology of SARS-CoV-2 in Essential Response Personnel (RECOVER) network as well as from surrounding communities. Child demographics, medical history, COVID-19 exposure, vaccination history, and parents/legal guardians' knowledge and attitudes about COVID-19 are collected at baseline and throughout the study. Mid-turbinate nasal specimens are self-collected or collected by parents/legal guardians weekly, regardless of symptoms, for SARS-CoV-2 and influenza testing via reverse transcription-polymerase chain reaction (RT-PCR) assay, and the presence of COVID-like illness (CLI) is reported. Children who test positive for SARS-CoV-2 or influenza, or report CLI are monitored weekly by online surveys to report exposure and medical utilization until no longer ill. Children, with permission of their parents/legal guardians, may elect to contribute blood at enrollment, following SARS-CoV-2 infection, following COVID-19 vaccination, and at the end of the study period. PROTECT uses electronic medical record (EMR) linkages where available, and verifies COVID-19 and influenza vaccinations through EMR or state vaccine registries. Data collection began in July 2021 and is expected to continue through the spring of 2023. As of April 13, 2022, 2371 children are enrolled in PROTECT. Enrollment is ongoing at all study sites. As COVID-19 vaccine products are authorized for use in pediatric populations, PROTECT study data will provide real-world estimates of VE in preventing infection. In addition, this prospective cohort provides a unique opportunity to further understand SARS-CoV-2 incidence, clinical course, and key knowledge gaps that may inform public health. RR1-10.2196/37929. ©Joy Burns, Patrick Rivers, Lindsay B LeClair, Krystal S Jovel, Ramona P Rai, Ashley A Lowe, Laura J Edwards, Sana M Khan, Clare Mathenge, Maria Ferraris, Jennifer L Kuntz, Julie Mayo Lamberte, Kurt T Hegmann, Marilyn J Odean, Hilary McLeland-Wieser, Shawn Beitel, Leah Odame-Bamfo, Natasha Schaefer Solle, Josephine Mak, Andrew L Phillips, Brian E Sokol, James Hollister, Jezahel S Ochoa, Lauren Grant, Matthew S Thiese, Keya B Jacoby, Karen Lutrick, Felipe A Pubillones, Young M Yoo, Danielle Rentz Hunt, Katherine Ellingson, Mark C Berry, Joe K Gerald, Joanna Lopez, Lynn B Gerald, Meredith G Wesley, Karl Krupp, Meghan K Herring, Purnima Madhivanan, Alberto J Caban-Martinez, Harmony L Tyner, Jennifer K Meece, Sarang K Yoon, Ashley L Fowlkes, Allison L Naleway, Lisa Gwynn, Jefferey L Burgess, Mark G Thompson, Lauren EW Olsho, Manjusha Gaglani. Originally published in JMIR Research Protocols (https://www.researchprotocols.org), 28.07.2022.</CopyrightInformation