Nucleic acid melting by Escherichia coli CspE

Escherichia coli contains nine members of the CspA family. CspA and some of its homologues play critical role in cold acclimation of cells by acting as RNA chaperones, destabilizing nucleicacid secondary structures. Disruption of nucleic acid melting activity of CspE led to loss of its transcription antitermination activity and consequently its cold acclimation activity. To date, the melting activity of Csp proteins was studied using partially double-stranded model nucleic acids substrates forming stem–loop structures. Here, we studied the mechanism of nucleic acid melting by CspE. We show that CspE melts the stem region in two directions, that CspE-induced melting does not require the continuity of the substrate's loop region, and CspE can efficiently melt model substrates with single-stranded overhangs as short as 4 nt. We further show that preferential binding of CspE at the stem–loop junction site initiates melting; binding of additional CspE molecules that fully cover the single-stranded region of a melting substrate leads to complete melting of the stem

Irritable Bowel Syndrome: Clinical Manifestations, Dietary Influences, and Management.

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder that is characterized by symptoms of chronic abdominal pain and altered bowel habits in the absence of an overtly identifiable cause. It is the most commonly diagnosed functional gastrointestinal disorder, accounting for about one third of gastroenterology visits. It generally presents as a complex of symptoms, including psychological dysfunction. Hypersensitivity to certain foods, especially foods that contain high amounts of fructose, plays a role in the pathophysiology of IBS. Elevated consumption of high-fructose corn syrup (HFCS) has been discussed in this aspect. The treatment options for IBS are challenging and varied. In addition to dietary restrictions for HFCS-induced IBS, such as low-FODMAP (Fermentable Oligosaccharides, Disaccharide, Monosaccharides, and Polyols) diets, existing drug therapies are administered based on the predominant symptoms and IBS-subtype. Patients with IBS are likely to suffer from issues, such as anxiety, depression, and post-traumatic-stress disorder. Biopsychosocial factors particularly socioeconomic status, sex, and race should, thus, be considered for diagnostic evaluation of patients with IBS

Clinical Factors Implicated in Antibiotic Resistance in Helicobacter pylori Patients

Helicobacter pylori is a common gastric pathogen associated with multiple clinical syndromes, including cancer. Eradication rates of H. pylori remain suboptimal despite the progress made in the past few decades in improving treatment strategies. The low eradication rates are mainly driven by antibiotic resistance of H. pylori. Non-invasive molecular testing to identify patients with antibiotic-resistant H. py-lori represents a promising therapeutic avenue, however this technology currently remains limited by availability, costs, and lack of robust validation. Moreover, there is insufficient evidence to demonstrate that resistance-testing-based treatment approaches are superior to appropriately designed empiric strat-egies. Consensus guidelines recommend use of proven locally effective regimens; however, eradication data are inconsistently generated in several regions of the world. In this review, we describe several clinical factors associated with increased rates of antibiotic resistant H. pylori, including history of previous antibiotic exposure, increasing age, female gender, ethnicity/race, extent of alcohol use, and non-ulcer dyspepsia. Assessment of these factors may aid the clinician in choosing the most appropriate empiric treatment strategy for each patient. Future study should aim to identify locally effective therapies and further explore the clinical factors associated with antibiotic resistance

Extended −10 Motif Is Critical for Activity of the cspA Promoter but Does Not Contribute to Low-Temperature Transcription

Bacterial promoters belonging to the extended −10 class contain a conserved TGn motif upstream of the −10 promoter consensus element. Open promoter complexes can be formed on some extended −10 Escherichia coli promoters at temperatures as low as 6°C, when complexes on most promoters are closed. The promoter of cspA, a gene that codes for the major cold shock protein CspA of E. coli, contains an extended −10 motif. CspA is dramatically induced upon temperature downshift from 37 to 15°C, and its cold shock induction has been attributed to transcription, translation, and mRNA stabilization effects. Here, we show that though the extended −10 motif is critical for high-level expression of cspA, it does not contribute to low-temperature expression. In fact, transcription from the wild-type cspA promoter is cold sensitive in vitro and in vivo. Thus, transcription appears to play little or no role in low-temperature induction of cspA expression

Probiotics for the Prevention of Antibiotic-Associated Diarrhea

Several communities have started using probiotic-rich fermented foods as therapeutic options with presumed medicinal powers. We now know the importance of microbiome balance and how probiotics can restore imbalances in the microbiome. Probiotics have been tested for a number of clinical uses such as the prevention of antibiotic-associated diarrhea (AAD), the treatment of various diseases such as H. pylori infection, irritable bowel disease, vaginitis, the prevention of allergies, and necrotizing enterocolitis in newborns. AAD has been the most indicated therapeutic use for probiotics. AAD is a common side effect of antibiotic usage, which affects up to 30% of patients. The hypothesis behind using probiotics for AAD is that they help normalize an unbalanced flora. There are many potential mechanisms by which probiotics support intestinal health such as (i) boosting immunity, (ii) increasing gut barrier integrity, (iii) producing antimicrobial substances, (iv) modulating the gut microbiome, (v) increasing water absorption, and (vi) decreasing opportunistic pathogens. Many randomized-controlled trials including the strain-specific trials that use Lactobacillus and Saccharomyces and meta-analyses have shown the benefits of probiotics in addressing AAD. Although adverse events have been reported for probiotics, these are broadly considered to be a safe and inexpensive preventative treatment option for AAD and other gastrointestinal disorders

An Interactive Session on Nutritional Pathologies for Health Professional Students

Various studies have emphasized the need to improve the nutrition training of health professionals, which will help them to provide optimal patient care. Nutrition-based interactive sessions may serve as an efficient approach to instigate an interest in nutrition among the students. Here we report the reception and effectiveness of a nutrition-pathology based interactive activity that we designed and implemented in the gastroenterology course given to the second year students at our medical school. The activity involved team work, individual accountability and peer-teaching. Nutrition pathology case stems (Kwashiorkor, vitamin B-12 deficiency, zinc deficiency and zinc-induced copper deficiency) were posted on the course website for the students to read before the session. At the start of the session, all the groups (each made up of four members) took a pre-quiz. Each student was then given an information sheet describing one case. Each group discussed the four cases with students acting as the “teacher” for the case assigned to them. A post-quiz was administered to the groups to assess acquisition of knowledge as well as in-depth thinking about the nutrition aspects discussed. The efficacy of the session measured by pre (39% questions correctly answered in total) and post-quizzes (96% questions correctly answered in total) and the overwhelmingly positive student feedback indicated that the session was highly effective. Ninety-five percent of students thought that the session demonstrated the clinical relevance of nutrition, while 98% students found the peer teaching to be engaging