Co-evolution of transcription factors and their targets depends on mode of regulation

BACKGROUND: Differences in the transcription regulation network are at the root of much of the phenotypic variation observed among organisms. These differences may be achieved either by changing the repertoire of regulators and/or their targets, or by rewiring the network. Following these changes and studying their logic is crucial for understanding the evolution of regulatory networks. RESULTS: We use the well characterized transcription regulatory network of Escherichia coli K12 and follow the evolutionary changes in the repertoire of regulators and their targets across a large number of fully sequenced γ-proteobacteria. By focusing on close relatives of E. coli K12, we study the dynamics of the evolution of transcription regulation across a relatively short evolutionary timescale. We show significant differences in the evolution of repressors and activators. Repressors are only lost from a genome once their targets have themselves been lost, or once the network has significantly rewired. In contrast, activators are often lost even when their targets remain in the genome. As a result, E. coli K12 repressors that regulate many targets are rarely absent from organisms that are closely related to E. coli K12, while activators with a similar number of targets are often absent in these organisms. CONCLUSION: We demonstrate that the mode of regulation exerted by transcription factors has a strong effect on their evolution. Repressors co-evolve tightly with their target genes. In contrast, activators can be lost independently of their targets. In fact, loss of an activator can lead to efficient shutdown of an unnecessary pathway

Combating STI Epidemic: Community Perspectives Learned from Mixed-Gender Focus Group Study

Background. Since 2004, Douglas County in Nebraska has been experiencing higher rates of sexually transmitted infections (STIs) than the rest of the state. Northern Omaha has been considered to be one of the “hot spots” for STIs in the county. In 2011-2012, a focus group study was conducted to investigate the community’s perception of STIs and to identify strategies to increase the testing and treatment of STIs. Methods. Fourteen young adults were recruited to participate in two mixed-gender focus group sessions, each lasting 1.5 hours. Sessions covered various topics on STIs. Audio-recorded sessions were transcribed and analyzed by the study team. Results. Participants were aware of the STI problem in their community. They identified risk factors for STIs included careless sexual behavior, unprotected sex, and lack of communication with parents. Participants believed that the club environment and drug and alcohol use contribute to risky sexual behavior. Participants perceived lack of confidentiality as the most important barrier to getting tested. The most important reason for not seeking treatment was lack of awareness about the signs of infection. Participants called for measures to increase trustworthy relationships with the health care system and suggested opening more testing and treatment sites. Discussion. The uniqueness of our study is that it is the first conducted epidemiological study in this population to better understand risk factors of STIs specific to this population. The study identified several important factors that may assist in future interventions to reduce STIs in this population

Small RNAs encoded within genetic islands of Salmonella typhimurium show host-induced expression and role in virulence

The emergence of pathogenic strains of enteric bacteria and their adaptation to unique niches are associated with the acquisition of foreign DNA segments termed ‘genetic islands’. We explored these islands for the occurrence of small RNA (sRNA) encoding genes. Previous systematic screens for enteric bacteria sRNAs were mainly carried out using the laboratory strain Escherichia coli K12, leading to the discovery of ∼80 new sRNA genes. These searches were based on conservation within closely related members of enteric bacteria and thus, sRNAs, unique to pathogenic strains were excluded. Here we describe the identification and characterization of 19 novel unique sRNA genes encoded within the ‘genetic islands’ of the virulent strain Salmonella typhimurium. We show that the expression of many of the island-encoded genes is associated with stress conditions and stationary phase. Several of these sRNA genes are induced when Salmonella resides within macrophages. One sRNA, IsrJ, was further examined and found to affect the translocation efficiency of virulence-associated effector proteins into nonphagocytic cells. In addition, we report that unlike the majority of the E. coli sRNAs that are trans regulators, many of the island-encoded sRNAs affect the expression of cis-encoded genes. Our study suggests that the island encoded sRNA genes play an important role within the network that regulates bacterial adaptation to environmental changes and stress conditions and thus controls virulence

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

SURVEY AND SUMMARY: A survey of small RNA-encoding genes in Escherichia coli

Small RNA (sRNA) molecules have gained much interest lately, as recent genome-wide studies have shown that they are widespread in a variety of organisms. The relatively small family of 10 known sRNA-encoding genes in Escherichia coli has been significantly expanded during the past two years with the discovery of 45 novel genes. Most of these genes are still uncharacterized and their cellular roles are unknown. In this survey we examined the sequence and genomic features of the 55 currently known sRNA-encoding genes in E.coli, attempting to identify their common characteristics. Such characterization is important for both expanding our understanding of this unique gene family and for improving the methods to predict and identify sRNA-encoding genes based on genomic information

Exploring Co-Regulation-Related Factors in the Mothers of ADHD Children—Proof of Concept Study

Background: Attention deficit hyperactivity disorder (ADHD) is a complex neurological condition interfering with family relationships and co-regulation capabilities. Therefore, exploring factors underpinning parental co-regulation ability is crucial for future fostering relationships in families of children with ADHD. Objective: This preliminary study aims to characterize and compare the executive-functions, anxiety, self-efficacy, and sensory modulation in mothers of children with and without ADHD. Method: Mothers of children with (study group) and without (control-comparison, group) ADHD completed online self-reports, measuring executive-functions; parental self-efficacy; anxiety; and sensory modulation. Results: The study group (N = 40) had lower self-efficacy compared to the control group (N = 27; p = 0.018), and the control group had lower sensory responsiveness (p = 0.025). Within both groups the Behavior Rating Inventory of Executive Function-Adult (BRIEF-A) Global Executive Function Composite score (GEC) and the Beck Anxiety Inventory (BAI) were moderately correlated. Further, within the study group correlations were found between the BRIEF-A-GEC and the Sensory Responsiveness Questionnaire (SRQ)-Aversive scores (r = 0.37, p ≤ 0.01), and between the BRIEF-A Behavioral-Rating-Index and the parental self-efficacy scores (r = 0.31, p ≤ 0.05). Within the control group, negative correlations were found between the BRIEF-A-GEC and SRQ-Hedonic scores (r= −0.44, p < 0.05). Conclusion: Self-efficacy, executive-functions, high sensory responsiveness and anxiety traits are interwoven and may impact parental co-regulation ability

Mental health problems due to community violence exposure in a small urban setting

Objective: Studies conducted in large metropolitan inner-city communities with high violent crime rates have demonstrated an association between exposure to violence and mental health problems; therefore the purpose of this study was to determine if similar trends exist in smaller inner-city communities with substantially lower violent crime rates. Methods: One hundred twenty-six children and young adults living in inner-city Omaha, Nebraska, were screened for posttraumatic stress disorder (PTSD), depression, and anxiety symptoms and assessed for community violence exposure (CVE). Pearson’s correlation and analysis of variance were used to determine the relationship between PTSD, depression, and anxiety symptoms and CVE. Results: A statistically significant relationship was found between CVE and PTSD and anxiety symptoms among participants despite their having lower rates of exposure to violent events in comparison with other studies. No association was found between violence and depression symptoms. Additionally, the presence of anxiety and depression, as well as increased age of participants, was associated with higher rates of PTSD symptoms. Conclusion: We recommend that health care providers in smaller cities, where the effects of violent crime may be underestimated or overlooked, be informed of the existence of this public health problem within their community and that they screen at-risk patients for mental health problems