Intact flagellar motor of Borrelia burgdorferi revealed by cryo-electron tomography: evidence for stator ring curvature and rotor/C-ring assembly flexion.

The bacterial flagellar motor is a remarkable nanomachine that provides motility through flagellar rotation. Prior structural studies have revealed the stunning complexity of the purified rotor and C-ring assemblies from flagellar motors. In this study, we used high-throughput cryo-electron tomography and image analysis of intact Borrelia burgdorferi to produce a three-dimensional (3-D) model of the in situ flagellar motor without imposing rotational symmetry. Structural details of B. burgdorferi, including a layer of outer surface proteins, were clearly visible in the resulting 3-D reconstructions. By averaging the 3-D images of approximately 1,280 flagellar motors, a approximately 3.5-nm-resolution model of the stator and rotor structures was obtained. flgI transposon mutants lacked a torus-shaped structure attached to the flagellar rod, establishing the structural location of the spirochetal P ring. Treatment of intact organisms with the nonionic detergent NP-40 resulted in dissolution of the outermost portion of the motor structure and the C ring, providing insight into the in situ arrangement of the stator and rotor structures. Structural elements associated with the stator followed the curvature of the cytoplasmic membrane. The rotor and the C ring also exhibited angular flexion, resulting in a slight narrowing of both structures in the direction perpendicular to the cell axis. These results indicate an inherent flexibility in the rotor-stator interaction. The FliG switching and energizing component likely provides much of the flexibility needed to maintain the interaction between the curved stator and the relatively symmetrical rotor/C-ring assembly during flagellar rotation

Optimizing identification of clinically relevant gram-positive organisms by use of the bruker biotyper matrix-assisted laser desorption ionization-time of flight mass spectrometry system

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) can be used as a method for the rapid identification of microorganisms. This study evaluated the Bruker Biotyper (MALDI-TOF MS) system for the identification of clinically relevant Gram-positive organisms. We tested 239 aerobic Gram-positive organisms isolated from clinical specimens. We evaluated 4 direct-smear methods, including “heavy” (H) and “light” (L) smears, with and without a 1-μl direct formic acid (FA) overlay. The quality measure assigned to a MALDI-TOF MS identification is a numerical value or “score.” We found that a heavy smear with a formic acid overlay (H+FA) produced optimal MALDI-TOF MS identification scores and the highest percentage of correctly identified organisms. Using a score of ≥2.0, we identified 183 of the 239 isolates (76.6%) to the genus level, and of the 181 isolates resolved to the species level, 141 isolates (77.9%) were correctly identified. To maximize the number of correct identifications while minimizing misidentifications, the data were analyzed using a score of ≥1.7 for genus- and species-level identification. Using this score, 220 of the 239 isolates (92.1%) were identified to the genus level, and of the 181 isolates resolved to the species level, 167 isolates (92.2%) could be assigned an accurate species identification. We also evaluated a subset of isolates for preanalytic factors that might influence MALDI-TOF MS identification. Frequent subcultures increased the number of unidentified isolates. Incubation temperatures and subcultures of the media did not alter the rate of identification. These data define the ideal bacterial preparation, identification score, and medium conditions for optimal identification of Gram-positive bacteria by use of MALDI-TOF MS

Correlates of physical activity and sedentary time in young adults: The Western Australian Pregnancy Cohort (Raine) Study

Background: The socioecological model proposes a wide array of factors that influence behaviours. There is a need to understand salient correlates of these activity behaviours in a specific population. However, few studies identified socio-demographic, behavioural, physical, and psychological correlates of objectively-assessed physical activity and sedentary time in young adults. Methods: This was a cross-sectional analysis of participants in the Raine Study (a pregnancy cohort started in 1989). Australian young adults (mean 22.1 years ± SD 0.6) wore Actigraph GT3X+ accelerometers on the hip 24 h/day for seven days to assess moderate-to-vigorous physical activity (MVPA) and sedentary time (n = 256 women, n = 219 men). Potential correlates were assessed via clinical assessment and questionnaire and included socio-demographic variables (ethnicity, relationship status, work/study status, education, mothers education), health behaviours (food intake, alcohol consumption, smoking status, sleep quality), and physical and psychological health aspects (anthropometrics, diagnosed disorders, mental health, cognitive performance). Backwards elimination (p < 0.2 for retention) with mixed model regressions were used and the gender-stratified analyses were adjusted for demographic variables, waking wear time and number of valid days. Results: Increased time spent in MVPA was associated with: being single (IRR 1.44 vs in a relationship living together, 95%CI: 1.17, 1.77, p =.001) in women; and better sleep quality in men (lower scores better IRR 0.97, 95%CI: 0.93, 1.00). Less time spent sedentary was associated with: lower mother's education (- 32.1 min/day, 95%CI -52.9, 11.3, p = 0.002 for having mother with no university degree vs at least a baccalaureate degree) and smoking (- 44.3 min/day, 95%CI: - 72.8, - 15.9, p =.0002) for women; lower education status (- 32.1 min/day, 95%CI: -59.5, - 4.8, p = 0.021 for having no university degree vs at least a baccalaureate degree) and lower depression scores in men (- 2.0, 95%CI: - 3.5, - 0.4, p = 0.014); more alcoholic drinks per week for women (- 1.9 min/day, 95%CI: -3.1, - 0.6, p = 0.003) and men (- 1.0, 95%CI: -1.8, - 0.3, p = 0.007). Conclusions: Less desirable correlates were associated with positive levels of activity in young Australian adult women and men. Interventions to increase MVPA and decrease sedentary activity in young adults need to specifically consider the life stage of young adults

“My Plate is Full”: Reasons for Declining a Genetic Evaluation of Hearing Loss

The aim of this study was to obtain patient and parent perspectives on genetic evaluation of hearing loss, in order to identify motivators, expectations, and barriers. Three focus groups were conducted following a semi‐structured discussion guide, led by an independent moderator. Participants were hearing parents of children with permanent hearing loss or deaf adults. Qualitative content analysis was used to develop a codebook and identify major themes and subthemes. Participant views were compared to national guidelines. The 28 participants comprised 23 parents representing 21 unique families and 5 deaf adults. 13/21 families and 0/5 adults reported comorbidities, 4/21 families and 3/5 adults had a positive family history, and 12/21 families versus 0/5 adults had utilized genetics services. A common theme among adults and parents was a curiosity as to the cause of hearing loss. Parents were motivated to detect comorbidities and optimize care for hearing loss. Some parents felt overwhelmed by the hearing loss and unprepared to pursue early genetic evaluation as recommended in guidelines. Several reported positive experiences following genetics consultation, while others reported unease and unmet expectations. Notably, both parents and adults expressed ambivalence regarding the desire for genetic knowledge. Financial concerns and difficulties obtaining a referral were cited as extrinsic barriers. For parents of children with hearing loss, both the presence of comorbidities and a positive family history were drivers of genetics consultation and/or genetic testing. We identified educational opportunities for both patients and providers that would improve informed decision‐making and increase access to genetic services. Consideration of the patient/family perspective and their decision‐making processes, along with flexibility in the approach to genetics evaluation and its timing, will optimize both the development and implementation of guidelines.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147183/1/jgc40597.pd

Fourteen propositions for resilience, fourteen years later

In 2006, Walker et al. published an article titled, “A Handful of Heuristics and Some Propositions for Understanding Resilience in Social-ecological Systems.” The article was incorporated into the Ecology and Society special feature, Exploring Resilience in Social-Ecological Systems. Walker et al. identified five heuristics and posed 14 propositions for understanding resilience in social-ecological systems. At the time, the authors hoped the paper would promote experimentation, critique, and application of these ideas in resilience and social-ecological systems research. To determine the extent to which these propositions have achieved the authors’ hopes, we reviewed the scientific literature on socialecological systems since the article was published. Using Scopus, we identified 627 articles that cited the Walker et al. article. We then identified and assessed the articles relative to each proposition. In addition, we conducted a more general Scopus review for articles that did not cite the Walker et al. article specifically but incorporated a proposition’s concepts. Overall, articles often cite Walker et al. as a reference for a definition of a heuristic or ecological resilience generally and not to reference a specific proposition. Nonetheless, every proposition was at least mentioned in the literature and used to advance resilience scholarship on social-ecological systems. Eleven propositions were tested by multiple articles through application of case studies or other research, and 7 of the 11 propositions were substantially discussed and advanced. Finally, three propositions were heavily critiqued either as concepts in resilience literature or in their application

PI3K-δ and PI3K-γ Inhibition by IPI-145 Abrogates Immune Responses and Suppresses Activity in Autoimmune and Inflammatory Disease Models

SummaryPhosphoinositide-3 kinase (PI3K)-δ and PI3K-γ are preferentially expressed in immune cells, and inhibitors targeting these isoforms are hypothesized to have anti-inflammatory activity by affecting the adaptive and innate immune response. We report on a potent oral PI3K-δ and PI3K-γ inhibitor (IPI-145) and characterize this compound in biochemical, cellular, and in vivo assays. These studies demonstrate that IPI-145 exerts profound effects on adaptive and innate immunity by inhibiting B and T cell proliferation, blocking neutrophil migration, and inhibiting basophil activation. We explored the therapeutic value of combined PI3K-δ and PI3K-γ blockade, and IPI-145 showed potent activity in collagen-induced arthritis, ovalbumin-induced asthma, and systemic lupus erythematosus rodent models. These findings support the hypothesis that inhibition of immune function can be achieved through PI3K-δ and PI3K-γ blockade, potentially leading to significant therapeutic effects in multiple inflammatory, autoimmune, and hematologic diseases

Implications of secondary findings in clinical context

B

Multi-ancestry study of blood lipid levels identifies four loci interacting with physical activity.

Many genetic loci affect circulating lipid levels, but it remains unknown whether lifestyle factors, such as physical activity, modify these genetic effects. To identify lipid loci interacting with physical activity, we performed genome-wide analyses of circulating HDL cholesterol, LDL cholesterol, and triglyceride levels in up to 120,979 individuals of European, African, Asian, Hispanic, and Brazilian ancestry, with follow-up of suggestive associations in an additional 131,012 individuals. We find four loci, in/near CLASP1, LHX1, SNTA1, and CNTNAP2, that are associated with circulating lipid levels through interaction with physical activity; higher levels of physical activity enhance the HDL cholesterol-increasing effects of the CLASP1, LHX1, and SNTA1 loci and attenuate the LDL cholesterol-increasing effect of the CNTNAP2 locus. The CLASP1, LHX1, and SNTA1 regions harbor genes linked to muscle function and lipid metabolism. Our results elucidate the role of physical activity interactions in the genetic contribution to blood lipid levels

SARS-CoV-2 Infects Human Engineered Heart Tissues and Models COVID-19 Myocarditis.

There is ongoing debate as to whether cardiac complications of coronavirus disease-2019 (COVID-19) result from myocardial viral infection or are secondary to systemic inflammation and/or thrombosis. We provide evidence that cardiomyocytes are infected in patients with COVID-19 myocarditis and are susceptible to severe acute respiratory syndrome coronavirus 2. We establish an engineered heart tissue model of COVID-19 myocardial pathology, define mechanisms of viral pathogenesis, and demonstrate that cardiomyocyte severe acute respiratory syndrome coronavirus 2 infection results in contractile deficits, cytokine production, sarcomere disassembly, and cell death. These findings implicate direct infection of cardiomyocytes in the pathogenesis of COVID-19 myocardial pathology and provides a model system to study this emerging disease

Objectively measured patterns of sedentary time and physical activity in young adults of the Raine study cohort

Background: To provide a detailed description of young adults' sedentary time and physical activity. Methods: 384 young women and 389 young men aged 22.1±0.6 years, all participants in the 22 year old follow-up of the Raine Study pregnancy cohort, wore Actigraph GT3X+ monitors on the hip for 24 h/day over a one-week period for at least one 'valid' day (=10 h of waking wear time). Each minute epoch was classified as sedentary, light, moderate or vigorous intensity using 100 count and Freedson cut-points. Mixed models assessed hourly and daily variation; t-tests assessed gender differences. Results: The average (mean±SD) waking wear time was 15.0±1.6 h/day, of which 61.4±10.1 % was spent sedentary, 34.6±9.1 % in light-, 3.7±5.3 % in moderate- and, 0.3±0.6 % in vigorous-intensity activity. Average time spent in moderate to vigorous activity (MVPA) was 36.2±27.5 min/day. Relative to men, women had higher sedentary time, but also higher vigorous activity time. The 'usual' bout duration of sedentary time was 11.8±4.5 min in women and 11.7±5.2 min in men. By contrast, other activities were accumulated in shorter bout durations. There was large variation by hour of the day and by day of the week in both sedentary time and MVPA. Evenings and Sundays through Wednesdays tended to be particularly sedentary and/or inactive. Conclusion: For these young adults, much of the waking day was spent sedentary and many participants were physically inactive (low levels of MVPA). We provide novel evidence on the time for which activities were performed and on the time periods when young adults were more sedentary and/or less active. With high sedentary time and low MVPA, young adults may be at risk for the life-course sequelae of these behaviours