Escherichia coli strains with precise domain deletions in the ribonuclease RNase E can achieve greatly enhanced levels of membrane protein production.

Escherichia coli is one of the most widely utilized hosts for production of recombinant membrane proteins (MPs). Bacterial MP production, however, is usually accompanied by severe toxicity and low-level volumetric accumulation. In previous work, we had discovered that co-expression of RraA, an inhibitor of the RNA-degrading activity of RNase E, can efficiently suppress the cytotoxicity associated with the MP overexpression process and, simultaneously, enhance significantly the cellular accumulation of membrane-incorporated recombinant MPs in bacteria. Based on this, we constructed the specialized MP-producing E. coli strain SuptoxR, which can achieve dramatically enhanced volumetric yields of well-folded recombinant MPs. Ιn the present work, we have investigated whether domain deletions in the E. coli RNase E, which exhibit reduced ribonucleolytic activity, can result in suppressed MP-induced toxicity and enhanced recombinant MP production, in a manner resembling the conditions of rraA overexpression in E. coli SuptoxR. We have found that some strains encoding specific RNase E truncation variants can achieve significantly enhanced levels of recombinant MP production. Among these, we have found a single RNase E variant strain, which can efficiently suppress MP-induced toxicity and achieve greatly enhanced levels of recombinant MP production for proteins of both prokaryotic and eukaryotic origin. Based on its properties, and in analogy to the original SuptoxR strain, we have termed this strain SuptoxRNE22. E. coli SuptoxRNE22 can perform better than commercially available bacterial strains, which are frequently utilized for recombinant MP production. We anticipate that SuptoxRNE22 will become a widely utilized host for recombinant MP production in bacteria.

Second-Generation Escherichia coli SuptoxR Strains for High-Level Recombinant Membrane Protein Production.

Escherichia coli is one of the most widely utilized hosts for recombinant protein production, including that of membrane proteins (MPs). We have recently engineered a specialized E. coli strain for enhanced recombinant MP production, termed SuptoxR. By appropriately co-expressing the effector gene rraA, SuptoxR can suppress the high toxicity, which is frequently observed during the MP-overexpression process, and, at the same time, enhance significantly the cellular accumulation of membrane-incorporated and properly folded recombinant MP. The combination of these two beneficial effects results in dramatically enhanced volumetric yields for various prokaryotic and eukaryotic MPs. Here, we engineered second-generation SuptoxR strains with further improved properties, so that they can achieve even higher levels of recombinant MP production. We searched for naturally occurring RraA variants with similar or improved MP toxicity-suppressing and production-promoting effects to that of the native E. coli RraA of the original SuptoxR strain. We found that the RraA proteins from Proteus mirabilis and Providencia stuartii can be even more potent enhancers of MP productivity than the E. coli RraA. By exploiting these two newly identified RraAs, we constructed two second-generation SuptoxR strains, termed SuptoxR2.1 and SuptoxR2.2, whose MP-production capabilities often surpass those of the original SuptoxR significantly. SuptoxR2.1 and SuptoxR2.2 are expected to become widely useful expression hosts for recombinant MP production in bacteria.

Evaluating Preoperative Anxiety Levels in Patients Undergoing Breast Cancer Surgery.

OBJECTIVE: Patients' anxiety and stress levels are increased after the surgery. High levels of anxiety and stress could increase postoperative complications, as well as to prolong postoperative hospitalization and postoperative morbidity. This prospective, cross-sectional study was to evaluate the preoperative stress levels in patients undergoing breast cancer surgery. METHODS: In the study participated 165 female patients who underwent breast cancer surgery, in a major oncological hospital in Greece. Demographic and clinical data were collected, and anxiety and stress levels assessed using the State-Trait Anxiety Inventory (STAI) Scale, which was a self-report questionnaire consisting of 40, 4 Likert Scale questions. The first 20 questions, STAI-X-1, were concerned to how the patient felt while answering the questionnaire (anxiety as a condition) and the remaining 20 questions, STAI-X-2, based on how the patient felt overall (stress as a personality trait). Descriptive statistics and nonparametric tests were performed at a significance level alpha = 0.05. RESULTS: In the present study, 165 females were enrolled who underwent breast cancer surgery. The mean age of the participants was 55.86 years, whereas the mean body mass index was 26.85. The 60.6% of patients underwent a lumpectomy and 28.5% had mastectomy. The 35.8% experienced moderate levels of anxiety, and the 17.6% experienced high levels. The two scales were positively correlated (rho = 0.643, P < 0.001), at the significance level P = 0.01. Furthermore, the Stai-X-2 Scale was negatively correlated with body height (rho = -0.1188, P = 0.016). CONCLUSIONS: The present study showed that patients' personality influenced their anxiety levels. Thus, the role of the nurse is a cornerstone in their psychological support preoperatively, to reduce the anxiety and stress levels.

Loneliness in Psychosis: A Meta-analytical Review.

Loneliness may be related to psychotic symptoms but a comprehensive synthesis of the literature in this area is lacking. The primary aim of the current study is to provide a systematic review and meta-analysis of the association between loneliness and psychotic symptoms in people with psychosis. A search of electronic databases was conducted (PsychINFO, MEDLINE, EMBASE, and Web of Science). A random effects meta-analysis was used to compute a pooled estimate of the correlation between loneliness and psychotic symptoms. Study and outcome quality were assessed using adapted versions of the Agency for Healthcare Research and Quality (AHRQ) tool and GRADE approach, respectively. Thirteen studies were included, providing data from 15 647 participants. A moderate association between psychosis and loneliness was observed (k = 13, N = 15 647, r = .32, 95% CI 0.20, 0.44; I2 = 97.56%; moderate quality evidence). Whether loneliness was assessed by a single-item or a more comprehensive measure had no moderating effect on the estimate. Results indicate that there is a significant positive relationship between loneliness and psychosis. Further studies are needed to determine the causal status of this relationship, but this robust finding should be considered in clinical practice and treatment provision for those with psychotic disorders.