A large-scale RNAi screen reveals that mitochondrial function is important for meiotic chromosome organization in oocytes.

In prophase of the first meiotic division, chromatin forms a compact spherical cluster called the karyosome within the enlarged oocyte nucleus in Drosophila melanogaster. Similar clustering of chromatin has been widely observed in oocytes in many species including humans. It was previously shown that the proper karyosome formation is required for faithful chromosome segregation, but knowledge about its formation and maintenance is limited. To identify genes involved in karyosome formation, we carried out a large-scale cytological screen using Drosophila melanogaster oocytes. This screen comprised 3916 genes expressed in ovaries, of which 106 genes triggered reproducible karyosome defects upon knockdown. The karyosome defects in 24 out of these 106 genes resulted from activation of the meiotic recombination checkpoint, suggesting possible roles in DNA repair or piRNA processing. The other genes identified in this screen include genes with functions linked to chromatin, nuclear envelope, and actin. We also found that silencing of genes with mitochondrial functions, including electron transport chain components, induced a distinct karyosome defect typically with de-clustered chromosomes located close to the nuclear envelope. Furthermore, mitochondrial dysfunction not only impairs karyosome formation and maintenance, but also delays synaptonemal complex disassembly in cells not destined to become the oocyte. These karyosome defects do not appear to be mediated by apoptosis. This large-scale unbiased study uncovered a set of genes required for karyosome formation and revealed a new link between mitochondrial dysfunction and chromatin organization in oocytes.

Mycobacterium tuberculosis Thioredoxin Reductase Is Essential for Thiol Redox Homeostasis but Plays a Minor Role in Antioxidant Defense.

Mycobacterium tuberculosis (Mtb) must cope with exogenous oxidative stress imposed by the host. Unlike other antioxidant enzymes, Mtb's thioredoxin reductase TrxB2 has been predicted to be essential not only to fight host defenses but also for in vitro growth. However, the specific physiological role of TrxB2 and its importance for Mtb pathogenesis remain undefined. Here we show that genetic inactivation of thioredoxin reductase perturbed several growth-essential processes, including sulfur and DNA metabolism and rapidly killed and lysed Mtb. Death was due to cidal thiol-specific oxidizing stress and prevented by a disulfide reductant. In contrast, thioredoxin reductase deficiency did not significantly increase susceptibility to oxidative and nitrosative stress. In vivo targeting TrxB2 eradicated Mtb during both acute and chronic phases of mouse infection. Deliberately leaky knockdown mutants identified the specificity of TrxB2 inhibitors and showed that partial inactivation of TrxB2 increased Mtb's susceptibility to rifampicin. These studies reveal TrxB2 as essential thiol-reducing enzyme in Mtb in vitro and during infection, establish the value of targeting TrxB2, and provide tools to accelerate the development of TrxB2 inhibitors.

Hsp90α and Hsp90ß together operate a hypoxia and nutrient paucity stress-response mechanism during wound healing.

When tissues are injured and blood vessels clot, the local environment becomes ischemic, meaning that there is a lack of adequate supply of oxygen and glucose delivered to the surrounding cells. The heat shock protein-90 (Hsp90) family proteins protect tissues from various environmental insults and participate in the repair of damaged tissue. Here, we report discovery of a new ischemia-responsive mechanism in which the two Hsp90 isoforms Hsp90α and Hsp90ß (also known as HSP90AA1 and HSP90AB1, respectively) work together to promote cell motility in wounded skin and accelerate wound closure. We demonstrate that Hsp90α and Hsp90ß have distinct and non-exchangeable functions during wound healing. Under hypoxia and when there is a lack of serum factors, Hsp90ß binds to the cytoplasmic tail of the LDL receptor-related protein-1 (LRP-1) and stabilizes the receptor at the cell surface. Hsp90α, however, is secreted by the cell into extracellular space where it binds and signals through the LRP-1 receptor to promote cell motility, leading to wound closure. In addition to skin injury, we suggest that this repair mechanism applies broadly to other non-cutaneous injured tissues.

The Diagnosis of Urinary Tract Infection in Young Children (DUTY) Study Clinical Rule: Economic Evaluation.

OBJECTIVE: To estimate the cost-effectiveness of a two-step clinical rule using symptoms, signs and dipstick testing to guide the diagnosis and antibiotic treatment of urinary tract infection (UTI) in acutely unwell young children presenting to primary care. METHODS: Decision analytic model synthesising data from a multicentre, prospective cohort study (DUTY) and the wider literature to estimate the short-term and lifetime costs and healthcare outcomes (symptomatic days, recurrent UTI, quality adjusted life years) of eight diagnostic strategies. We compared GP clinical judgement with three strategies based on a 'coefficient score' combining seven symptoms and signs independently associated with UTI and four strategies based on weighted scores according to the presence/absence of five symptoms and signs. We compared dipstick testing versus laboratory culture in children at intermediate risk of UTI. RESULTS: Sampling, culture and antibiotic costs were lowest in high-specificity DUTY strategies (£1.22 and £1.08) compared to clinical judgement (£1.99). These strategies also approximately halved urine sampling (4.8% versus 9.1% in clinical judgement) without reducing sensitivity (58.2% versus 56.4%). Outcomes were very similar across all diagnostic strategies. High-specificity DUTY strategies were more cost-effective than clinical judgement in the short- (iNMB = £0.78 and £0.84) and long-term (iNMB =£2.31 and £2.50). Dipstick tests had poorer cost-effectiveness than laboratory culture in children at intermediate risk of UTI (iNMB = £-1.41). CONCLUSIONS: Compared to GPs' clinical judgement, high specificity clinical rules from the DUTY study could substantially reduce urine sampling, achieving lower costs and equivalent patient outcomes. Dipstick testing children for UTI is not cost-effective.

Post-translational regulation via Clp protease is critical for survival of Mycobacterium tuberculosis.

Unlike most bacterial species, Mycobacterium tuberculosis depends on the Clp proteolysis system for survival even in in vitro conditions. We hypothesized that Clp is required for the physiologic turnover of mycobacterial proteins whose accumulation is deleterious to bacterial growth and survival. To identify cellular substrates, we employed quantitative proteomics and transcriptomics to identify the set of proteins that accumulated upon the loss of functional Clp protease. Among the set of potential Clp substrates uncovered, we were able to unambiguously identify WhiB1, an essential transcriptional repressor capable of auto-repression, as a substrate of the mycobacterial Clp protease. Dysregulation of WhiB1 turnover had a toxic effect that was not rescued by repression of whiB1 transcription. Thus, under normal growth conditions, Clp protease is the predominant regulatory check on the levels of potentially toxic cellular proteins. Our findings add to the growing evidence of how post-translational regulation plays a critical role in the regulation of bacterial physiology.

Improving the Diagnosis and Treatment of Urinary Tract Infection in Young Children in Primary Care: Results from the DUTY Prospective Diagnostic Cohort Study.

PURPOSE: Up to 50% of urinary tract infections (UTIs) in young children are missed in primary care. Urine culture is essential for diagnosis, but urine collection is often difficult. Our aim was to derive and internally validate a 2-step clinical rule using (1) symptoms and signs to select children for urine collection; and (2) symptoms, signs, and dipstick testing to guide antibiotic treatment. METHODS: We recruited acutely unwell children aged under 5 years from 233 primary care sites across England and Wales. Index tests were parent-reported symptoms, clinician-reported signs, urine dipstick results, and clinician opinion of UTI likelihood (clinical diagnosis before dipstick and culture). The reference standard was microbiologically confirmed UTI cultured from a clean-catch urine sample. We calculated sensitivity, specificity, and area under the receiver operator characteristic (AUROC) curve of coefficient-based (graded severity) and points-based (dichotomized) symptom/sign logistic regression models, and we then internally validated the AUROC using bootstrapping. RESULTS: Three thousand thirty-six children provided urine samples, and culture results were available for 2,740 (90%). Of these results, 60 (2.2%) were positive: the clinical diagnosis was 46.6% sensitive, with an AUROC of 0.77. Previous UTI, increasing pain/crying on passing urine, increasingly smelly urine, absence of severe cough, increasing clinician impression of severe illness, abdominal tenderness on examination, and normal findings on ear examination were associated with UTI. The validated coefficient- and points-based model AUROCs were 0.87 and 0.86, respectively, increasing to 0.90 and 0.90, respectively, by adding dipstick nitrites, leukocytes, and blood. CONCLUSIONS: A clinical rule based on symptoms and signs is superior to clinician diagnosis and performs well for identifying young children for noninvasive urine sampling. Dipstick results add further diagnostic value for empiric antibiotic treatment.

Empiric antibiotic treatment for urinary tract infection in preschool children: susceptibilities of urine sample isolates.

BACKGROUND: Antibiotic treatment recommendations based on susceptibility data from routinely submitted urine samples may be biased because of variation in sampling, laboratory procedures and inclusion of repeat samples, leading to uncertainty about empirical treatment. OBJECTIVE: To describe and compare susceptibilities of Escherichia coli cultured from routinely submitted samples, with E. coli causing urinary tract infection (UTI) from a cohort of systematically sampled, acutely unwell children. METHODS: Susceptibilities of 1458 E. coli isolates submitted during the course of routine primary care for children <5 years (routine care samples), compared to susceptibilities of 79 E. coli isolates causing UTI from 5107 children <5 years presenting to primary care with an acute illness [systematic sampling: the Diagnosis of Urinary Tract infection in Young children (DUTY) cohort]. RESULTS: The percentage of E. coli sensitive to antibiotics cultured from routinely submitted samples were as follows: amoxicillin 45.1% (95% confidence interval: 42.5-47.7%); co-amoxiclav using the lower systemic break point (BP) 86.6% (84.7-88.3%); cephalexin 95.1% (93.9-96.1%); trimethoprim 74.0% (71.7-76.2%) and nitrofurantoin 98.2% (97.4-98.8%). The percentage of E. coli sensitive to antibiotics cultured from systematically sampled DUTY urines considered to be positive for UTI were as follows: amoxicillin 50.6% (39.8-61.4%); co-amoxiclav using the systemic BP 83.5% (73.9-90.1%); co-amoxiclav using the urinary BP 94.9% (87.7-98.4%); cephalexin 98.7% (93.2-99.8%); trimethoprim 70.9% (60.1-80.0%); nitrofurantoin 100% (95.3-100.0%) and ciprofloxacin 96.2% (89.4-98.7%). CONCLUSION: Escherichia coli susceptibilities from routine and systematically obtained samples were similar. Most UTIs in preschool children remain susceptible to nitrofurantoin, co-amoxiclav and cephalexin.

A genetic strategy to identify targets for the development of drugs that prevent bacterial persistence.

Antibacterial drug development suffers from a paucity of targets whose inhibition kills replicating and nonreplicating bacteria. The latter include phenotypically dormant cells, known as persisters, which are tolerant to many antibiotics and often contribute to failure in the treatment of chronic infections. This is nowhere more apparent than in tuberculosis caused by Mycobacterium tuberculosis, a pathogen that tolerates many antibiotics once it ceases to replicate. We developed a strategy to identify proteins that Mycobacterium tuberculosis requires to both grow and persist and whose inhibition has the potential to prevent drug tolerance and persister formation. This strategy is based on a tunable dual-control genetic switch that provides a regulatory range spanning three orders of magnitude, quickly depletes proteins in both replicating and nonreplicating mycobacteria, and exhibits increased robustness to phenotypic reversion. Using this switch, we demonstrated that depletion of the nicotinamide adenine dinucleotide synthetase (NadE) rapidly killed Mycobacterium tuberculosis under conditions of standard growth and nonreplicative persistence induced by oxygen and nutrient limitation as well as during the acute and chronic phases of infection in mice. These findings establish the dual-control switch as a robust tool with which to probe the essentiality of Mycobacterium tuberculosis proteins under different conditions, including those that induce antibiotic tolerance, and NadE as a target with the potential to shorten current tuberculosis chemotherapies.

Development of Home Educational Materials for Families of Preterm Infants.

INTRODUCTION: Parent educational materials describing infant positioning for a home program are vital in supplementing NICU discharge instructions and promoting parent confidence. PURPOSE: To document the process of developing a brochure and DVD of a positioning program, using evidence-based practice and NICU expert feedback. METHODS: A trifold brochure and companion DVD were developed to demonstrate infant positioning to parents of premature infants for a home developmental program following NICU discharge. A standard process of development was followed for the brochure and DVD script and production. The process included review and comment by eight NICU professionals and several revisions. RESULTS: Content of the brochure and DVD and the process entailed in their development is described. Guidelines outlining the process for development of educational materials for families are provided. CONCLUSION: Creation of multimedia educational materials for parents of infants who are NICU graduates requires a multistep process to ensure usefulness and validity.

The product of Kaposi's sarcoma-associated herpesvirus immediate early gene K4.2 regulates immunoglobulin secretion and calcium homeostasis by interacting with and inhibiting pERP1.

Chaperones are proteins that assist the noncovalent folding and assembly of macromolecular polypeptide chains, ultimately preventing the formation of nonfunctional or potentially toxic protein aggregates. Plasma cell-induced-endoplasmic reticulum (ER)-resident protein 1 (pERP1) is a cellular chaperone that is preferentially expressed in marginal-zone B cells and is highly upregulated during plasma cell differentiation. While initially identified as a dedicated factor for the assembly of secreted IgM, pERP1 has since been implicated in suppressing calcium mobilization, and its expression is misregulated in multiple tumors. A number of herpesvirus immediate early gene products play important roles in the regulation of viral gene expression and/or evasion of host immune responses. Here, we report that the Kaposi's sarcoma-associated herpesvirus (KSHV) immediate early viral gene K4.2 encodes an endoplasmic reticulum-localized protein that interacts with and inhibits pERP1. Consequently, K4.2 expression interfered with immunoglobulin secretion by delaying the kinetics of immunoglobulin assembly and also led to increased responsiveness of B-cell receptor signal transduction by enhancing phosphotyrosine signals and intracellular calcium fluxes. Furthermore, K4.2 expression also appeared to contribute to maximal lytic replication by enhancing viral glycoprotein expression levels and ultimately promoting infectious-virus production. Finally, immunohistochemistry analysis showed that pERP1 expression was readily detected in KSHV-positive cells from multicentric Castleman's disease (MCD) and Kaposi's sarcoma (KS) lesions, suggesting that pERP1 may have potential roles in the KSHV life cycle and malignancy. In conclusion, our data suggest that K4.2 participates in lytic replication by enhancing calcium flux and viral glycoprotein expression, but also by interfering with immunoglobulin assembly to potentially dampen the adaptive immune response.

Development of complexity categories for an investigational drug services complexity scoring tool to assess pharmacy effort in clinical trial initiation and maintenance.

PURPOSE: Research pharmacy effort required to safely and compliantly manage investigational products (IP) varies between studies. No validated tool exists in the United States to evaluate these differences in effort. The Vizient Pharmacy Research Committee Investigational Drug Services (IDS) Subcommittee previously developed a systematic complexity scoring tool (CST) through expert consensus to assign a complexity score for pharmacy effort. This project seeks to develop and validate complexity categories based on CST scores. METHODS: Vizient member institutions in IDS assigned a CST complexity score and a perceived complexity category (low, medium, or high) for study initiation and maintenance. Receiver operating characteristic (ROC) curve analysis defined the best CST score cutoff points for each complexity category. Comparing the CST-assigned to the user-perceived complexity category determined whether the CST-assigned complexity category aligned with practitioner assignment. RESULTS: A total of 322 responses were used to determine complexity score categories. The AUC values for study initiation and maintenance were 0.79 (P < 0.001) for the low/medium boundary and 0.80 (P < 0.001) for the medium/high boundary, suggesting the performance of the CST is good. The agreement between CST-assigned and user-perceived complexity categories was 60% for study initiation and 58% for maintenance. The Kendall rank correlation coefficient between the raters and ROC categories was strong, with a value of 0.48 for study initiation and 0.47 for maintenance. CONCLUSION: Development of the CST allows IDS pharmacies to objectively measure the complexity of clinical trials, which is a significant step towards assessing workload and guiding resource allocation.

Validation of MYC and BCL6 rapid break apart digital fluorescence in situ hybridization assays for clinical use.

OBJECTIVE: Detection of gene rearrangements in MYC (a family of regulator genes and proto-oncogenes) and human B-cell lymphoma 6 (BCL6) using fluorescence in situ hybridization (FISH) are important in the evaluation of lymphomas, in particular diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma. Our current clinical MYC and BCL6 FISH workflow involves an overnight hybridization of probes with digital analysis using the GenASIs Scan and Analysis instrument (Applied Spectral Imaging). In order to improve assay turnaround time SureFISH probes were validated to reduce the hybridization time from 16 hours down to 1.5 hours. METHODS: Validation was a four-phase process involving initial development of the assays by testing new probes in a manual protocol, and cytogenetic studies to confirm the probe specificity, sensitivity, and localization. In the next phase, the assays were validated as a manual assay. The third phase involved development of the digital FISH assays by testing and optimizing the GenASIs Scan and Analysis instrument. In the final phase, the digital FISH assays were validated. RESULTS: Cytogenetic studies confirmed 100% probe sensitivity/specificity, and localization patterns. Negative reference range cutoffs calculated from 20 normal lymph nodes using the inverse of the beta cumulative probability density function (Excel BETAINV calculation) were 11% inclusive for both manual and digital MYC and BCL6 assays. There was 100% concordance between the manual and digital methods. The shortened hybridization time decreased the overall workflow time by 14.5 hours. CONCLUSIONS: This study validates the use of the SureFISH MYC and BCL6 probes on formalin fixed paraffin embedded (FFPE) tissue sections using a hybridization time of 1.5 hours that shortened the overall workflow by 14.5 hours. The process described also provides a standardized framework for validating digital FISH assays in the future.

An exploration of the perceived changes in intimacy of patients' relationships following head and neck cancer.

AIMS AND OBJECTIVES: This paper reports the experiences of former patients who have undergone a range of head and neck cancer treatments and their perceptions of the changes in intimacy experienced, as an individual and through their relationships with partners, family and friends. BACKGROUND: A diagnosis of head and neck cancer, subsequent surgical treatment and radiotherapy can lead to an altered quality of life. Whilst important developments have been made to improve the quality of life for this patient group from a functional perspective, psychosocial perspectives are much less understood. DESIGN: A qualitative study approach. METHODS: Data were collected in 2007/2008 via interview using open-ended questions from a purposive sample of 16 participants who were at least one year post-treatment. A thematic analysis was employed to interpret the findings. RESULTS: Analysis of the data produced three broad themes. These were 'personal identity', 're-establishing social networks' and 'intimate relationships' and explored the person as an individual and their perceived changes to self-esteem and image. The perception of their altered position in society, the impact this has on their willingness to re-engage with society and the degree to which treatment can alter an individual's ability to resume former intimate relationships with family and partners. CONCLUSION: Patients' definitions of intimacy are multifaceted and related directly to the type of relationship that existed prior to treatment. The concerns and challenges faced by patients need to be addressed and support opportunities considered as part of the rehabilitation process. RELEVANCE TO CLINICAL PRACTICE: The paper gives insight for nurses and other healthcare professionals who are expected to provide effective emotional and therapeutic support for patients who have undergone treatment for head and neck cancer. Understanding of patient concerns and recognition of adaptive and coping strategies are essential for this practice.

Prevalence of urinary tract infection (UTI) in sequential acutely unwell children presenting in primary care: exploratory study.

BACKGROUND: Due to the non-specific nature of symptoms of UTI in children and low levels of urine sampling, the prevalence of UTI amongst acutely ill children in primary care is unknown. OBJECTIVES: To undertake an exploratory study of acutely ill children consulting in primary care, determine the feasibility of obtaining urine samples, and describe presenting symptoms and signs, and the proportion with UTI. DESIGN: Exploratory, observational study. SETTING: Four general practices in South Wales. SUBJECTS: A total of 99 sequential attendees with acute illness aged less than five years. MAIN OUTCOME MEASURE: UTI defined by >10(5) organisms/ml on laboratory culture of urine. RESULTS: Urine samples were obtained in 75 (76%) children. Three (4%) met microbiological criteria for UTI. GPs indicated they would not normally have obtained urine samples in any of these three children. However, all had received antibiotics for suspected alternative infections. CONCLUSION: Urine sample collection is feasible from the majority of acutely ill children in primary care, including infants. Some cases of UTI may be missed if children thought to have an alternative site of infection are excluded from urine sampling. A larger study is needed to more accurately determine the prevalence of UTI in children consulting with acute illness in primary care, and to explore which symptoms and signs might help clinicians effectively target urine sampling.

The Impact of COVID-19 and Associated Interventions on Mental Health: A Cross-Sectional Study in a Sample of University Students.

BACKGROUND: Mental health issues have continued to rise globally, including among university students. The COVID-19 pandemic has exacerbated the previously existing and concerning problem. Given that coping mechanisms have been proposed to mediate the relationship between stressors and mental health, the aim of our cross-sectional study was to investigate the mediation of coping mechanisms on the relationship between the impact of the COVID-19 pandemic and mental health. METHODS: University students (≥18 years old; N = 676; 31% male, 69% female) were administered an anonymous survey addressing current demographics, COVID-19 pandemic-related demographics, personal experiences, sources of stress and perceived effect on mental health, politics, sources of news/information, and various pre-validated scales addressing mental health (DASS-21), the impact of the COVID-19 pandemic (IES-R) and coping strategies utilized (Brief COPE). RESULTS: Our results indicate a substantial proportion of our sample reporting scores in the severe and extremely severe DASS-21 categories, in addition to ~50% reporting a perceived deterioration in mental health relative to pre-COVID-19 pandemic. Moreover, a substantial proportion of students reported IES-R scores at levels where PTSD is of clinical concern. Alarmingly, a significant proportion of females (~15%) reported scores reflecting potential long-term PTSD-related implications. Females tended to be more severely impacted in all mental health measures. Mediation analysis indicated that while dysfunctional coping mediated the relationship between the impact of the event (COVID-19 pandemic) and all three mental health outcomes, overall, this was not the case with the positive coping strategies. CONCLUSION: Our study appears to indicate a reduced buffering influence on negative mental health outcomes by the positive coping mechanisms investigated in relation to the COVID-19 pandemic and secondary interventions implemented. While the findings of this study pertain specifically to university students, they corroborate the existing extensive body of research (from physiological to behavioral, preclinical to clinical) pertaining to the response associated with major stressful events at every level of society. In this regard, the findings imply the necessity for health and other authorities, tasked with safeguarding public well-being, to avoid reactive interventions that do not appropriately balance the risks and benefits, potentially exacerbating pre-existing psychopathologies and compromising social order.

A survey to understand the feelings towards and impact of COVID-19 on the households of juvenile dermato myositis patients from a parent or carer perspective.

OBJECTIVES: This aim of this study was to gain a better understanding of how parents and carers feel about the effects and impact of the coronavirus disease 2019 (COVID-19) pandemic lockdown and how this impacted upon their child/young person with JDM. METHOD: We approached 139 participants from the JDM Cohort Biomarker Study (JDCBS), with specific consent to approach electronically for research studies. A secure electronic questionnaire with study introduction was sent to participants for their parents and carers around the UK to complete. It consisted of 20 questions about the impact of the pandemic on their child or young person's clinical care. Data were analysed quantitatively and qualitatively. RESULTS: There were 76 (55%) responses to the survey. More than 50% of participants were actively being treated for their JDM at the point of survey completion as recorded by their parent or carer. More than 40% attested to disrupted treatment owing to COVID-19. The biggest impact upon clinical care was cancellation of appointments, initiating virtual appointments and extension of time between blood tests. Parents and carers expressed their own feelings of worry, concern and anxiety, but also those of their child or young person. CONCLUSION: Families who have a child or young person with JDM have been affected by COVID-19. Qualitative comments highlight that it has been a very difficult time. Further investigation is required into this area and could be compared with research on the effects of COVID-19 on other patient groups with chronic disease.

Favorable antibody responses to human coronaviruses in children and adolescents with autoimmune rheumatic diseases.

BACKGROUND: Differences in humoral immunity to coronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), between children and adults remain unexplained, and the effect of underlying immune dysfunction or suppression is unknown. Here, we sought to examine the antibody immune competence of children and adolescents with prevalent inflammatory rheumatic diseases, juvenile idiopathic arthritis (JIA), juvenile dermatomyositis (JDM), and juvenile systemic lupus erythematosus (JSLE) against the seasonal human coronavirus (HCoV)-OC43 that frequently infects this age group. METHODS: Sera were collected from JIA (n = 118), JDM (n = 49), and JSLE (n = 30) patients and from healthy control (n = 54) children and adolescents prior to the coronavirus disease 19 (COVID-19) pandemic. We used sensitive flow-cytometry-based assays to determine titers of antibodies that reacted with the spike and nucleoprotein of HCoV-OC43 and cross-reacted with the spike and nucleoprotein of SARS-CoV-2, and we compared them with respective titers in sera from patients with multisystem inflammatory syndrome in children and adolescents (MIS-C). FINDINGS: Despite immune dysfunction and immunosuppressive treatment, JIA, JDM, and JSLE patients maintained comparable or stronger humoral responses than healthier peers, which was dominated by immunoglobulin G (IgG) antibodies to HCoV-OC43 spike, and harbored IgG antibodies that cross-reacted with SARS-CoV-2 spike. In contrast, responses to HCoV-OC43 and SARS-CoV-2 nucleoproteins exhibited delayed age-dependent class-switching and were not elevated in JIA, JDM, and JSLE patients, which argues against increased exposure. CONCLUSIONS: Consequently, autoimmune rheumatic diseases and their treatment were associated with a favorable ratio of spike to nucleoprotein antibodies. FUNDING: This work was supported by a Centre of Excellence Centre for Adolescent Rheumatology Versus Arthritis grant, 21593, UKRI funding reference MR/R013926/1, the Great Ormond Street Children's Charity, Cure JM Foundation, Myositis UK, Lupus UK, and the NIHR Biomedical Research Centres at GOSH and UCLH. This work was supported by the Francis Crick Institute, which receives its core funding from Cancer Research UK, the UK Medical Research Council, and the Wellcome Trust.

Mechanism of protein splicing of the Pyrococcus abyssi lon protease intein.

Protein splicing is a post-translational process by which an intervening polypeptide, the intein, excises itself from the flanking polypeptides, the exteins, coupled to ligation of the exteins. The lon protease of Pyrococcus abyssi (Pab) is interrupted by an intein. When over-expressed as a fusion protein in Escherichia coli, the Pab lon protease intein can promote efficient protein splicing. Mutations that block individual steps of splicing generally do not lead to unproductive side reactions, suggesting that the intein tightly coordinates the splicing process. The intein can splice, although it has Lys in place of the highly conserved penultimate His, and mutants of the intein in the C-terminal region lead to the accumulation of stable branched-ester intermediate.

Plasticity of the Mycobacterium tuberculosis respiratory chain and its impact on tuberculosis drug development.

The viability of Mycobacterium tuberculosis (Mtb) depends on energy generated by its respiratory chain. Cytochrome bc1-aa3 oxidase and type-2 NADH dehydrogenase (NDH-2) are respiratory chain components predicted to be essential, and are currently targeted for drug development. Here we demonstrate that an Mtb cytochrome bc1-aa3 oxidase deletion mutant is viable and only partially attenuated in mice. Moreover, treatment of Mtb-infected marmosets with a cytochrome bc1-aa3 oxidase inhibitor controls disease progression and reduces lesion-associated inflammation, but most lesions become cavitary. Deletion of both NDH-2 encoding genes (Δndh-2 mutant) reveals that the essentiality of NDH-2 as shown in standard growth media is due to the presence of fatty acids. The Δndh-2 mutant is only mildly attenuated in mice and not differently susceptible to clofazimine, a drug in clinical use proposed to engage NDH-2. These results demonstrate the intrinsic plasticity of Mtb's respiratory chain, and highlight the challenges associated with targeting the pathogen's respiratory enzymes for tuberculosis drug development.