Tuberculosis vaccine strain _Mycobacterium bovis_ BCG Russia is a natural _recA_ mutant

The current tuberculosis vaccine is a live vaccine derived from _Mycobacterium bovis_ and attenuated by serial _in vitro_ passaging. All vaccine substrains in use stem from one source, strain Bacille Calmette-Guérin. However, they differ in regions of genomic deletions, antigen expression levels, immunogenicity, and protective efficacy. As a RecA phenotype increases genetic stability and may contribute restricting the ongoing evolution of the various BCG substrains, we aimed to inactivate _recA_ by allelic replacement in BCG vaccine strains representing different phylogenetic lineages (Pasteur, Frappier, Denmark, Russia). Homologous gene replacement was successful in three out of four strains. However, only illegitimate recombination was observed in BCG substrain Russia. Sequence analyses of _recA_ revealed that a single nucleotide insertion in the 5' part of _recA_ led to a translational frameshift with an early stop codon making BCG Russia a natural _recA_ mutant. At the protein level BCG Russia failed to express RecA. According to phylogenetic analyses BCG Russia is an ancient vaccine strain most closely related to the parental _M. bovis_. Our data suggest that _recA_ inactivation in BCG Russia occurred early and is in part responsible for its high degree of genomic stability, resulting in a substrain that has less genetic alterations than other vaccine substrains with respect to _M. bovis_ AF2122/97 wild type

Renormalization of the electron-phonon coupling in the one-band Hubbard model

We investigate the effect of electronic correlations on the coupling of electrons to Holstein phonons in the one-band Hubbard model. We calculate the static electron-phonon vertex within linear response of Kotliar-Ruckenstein slave-bosons in the paramagnetic saddle-point approximation. Within this approach the on-site Coulomb interaction U strongly suppresses the coupling to Holstein phonons at low temperatures. Moreover the vertex function does not show particularly strong forward scattering. Going to larger temperatures kT\sim t we find that after an initial decrease with U, the electron-phonon coupling starts to increase with U, confirming a recent result of Cerruti, Cappelluti, and Pietronero. We show that this behavior is related to an unusual reentrant behavior from a phase separated to a paramagnetic state upon decreasing the temperature.Comment: 4 pages, 6 figure

Oceanographic drivers of deep-sea coral species distribution and community assembly on seamounts, islands, atolls, and reefs within the Phoenix Islands Protected Area

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Auscavitch, S. R., Deere, M. C., Keller, A. G., Rotjan, R. D., Shank, T. M., & Cordes, E. E. Oceanographic drivers of deep-sea coral species distribution and community assembly on seamounts, islands, atolls, and reefs within the Phoenix Islands Protected Area. Frontiers in Marine Science, 7, (2020): 42, doi:10.3389/fmars.2020.00042.The Phoenix Islands Protected Area, in the central Pacific waters of the Republic of Kiribati, is a model for large marine protected area (MPA) development and maintenance, but baseline records of the protected biodiversity in its largest environment, the deep sea (>200 m), have not yet been determined. In general, the equatorial central Pacific lacks biogeographic perspective on deep-sea benthic communities compared to more well-studied regions of the North and South Pacific Ocean. In 2017, explorations by the NOAA ship Okeanos Explorer and R/V Falkor were among the first to document the diversity and distribution of deep-water benthic megafauna on numerous seamounts, islands, shallow coral reef banks, and atolls in the region. Here, we present baseline deep-sea coral species distribution and community assembly patterns within the Scleractinia, Octocorallia, Antipatharia, and Zoantharia with respect to different seafloor features and abiotic environmental variables across bathyal depths (200–2500 m). Remotely operated vehicle (ROV) transects were performed on 17 features throughout the Phoenix Islands and Tokelau Ridge Seamounts resulting in the observation of 12,828 deep-water corals and 167 identifiable morphospecies. Anthozoan assemblages were largely octocoral-dominated consisting of 78% of all observations with seamounts having a greater number of observed morphospecies compared to other feature types. Overlying water masses were observed to have significant effects on community assembly across bathyal depths. Revised species inventories further suggest that the protected area it is an area of biogeographic overlap for Pacific deep-water corals, containing species observed across bathyal provinces in the North Pacific, Southwest Pacific, and Western Pacific. These results underscore significant geographic and environmental complexity associated with deep-sea coral communities that remain in under-characterized in the equatorial central Pacific, but also highlight the additional efforts that need to be brought forth to effectively establish baseline ecological metrics in data deficient bathyal provinces.Funding for this work was provided by NOAA Office of Ocean Exploration and Research (Grant No. NA17OAR0110083) to RR, EC, TS, and David Gruber

New Approaches for ab initio Calculations of Molecules with Strong Electron Correlation

Reliable quantum chemical methods for the description of molecules with dense-lying frontier orbitals are needed in the context of many chemical compounds and reactions. Here, we review developments that led to our newcomputational toolbo x which implements the quantum chemical density matrix renormalization group in a second-generation algorithm. We present an overview of the different components of this toolbox.Comment: 19 pages, 1 tabl

Productie bioplastics biedt kansen voor farmaceutische toepassingen:de zoektocht naar het ultieme alternatief voor traditionele plastics zet zich al vele jaren voort. Het samenwerkingsverband BERNN is een van de initiatieven die zich op de ontwikkeling van bioplastics richt.

Artikel in Agro & Chemie over de productie van exogene ketonen in het projecten Circulaire Biopolymeren Waardeketens voor PHA en Cellulose

Tuberculosis vaccine strain Mycobacterium bovis BCG Russia is a natural recA mutant

BACKGROUND: The current tuberculosis vaccine is a live vaccine derived from Mycobacterium bovis and attenuated by serial in vitro passaging. All vaccine substrains in use stem from one source, strain Bacille Calmette-Guérin. However, they differ in regions of genomic deletions, antigen expression levels, immunogenicity, and protective efficacy. RESULTS: As a RecA phenotype increases genetic stability and may contribute restricting the ongoing evolution of the various BCG substrains while maintaining their protective efficacy, we aimed to inactivate recA by allelic replacement in BCG vaccine strains representing different phylogenetic lineages (Pasteur, Frappier, Denmark, Russia). Homologous gene replacement was achieved successfully in three out of four strains. However, only illegitimate recombination was observed in BCG substrain Russia. Sequence analyses of recA revealed that a single nucleotide insertion in the 5' part of recA led to a translational frameshift with an early stop codon making BCG Russia a natural recA mutant. At the protein level BCG Russia failed to express RecA. CONCLUSION: According to phylogenetic analyses BCG Russia is an ancient vaccine strain most closely related to the parental M. bovis. We hypothesize that recA inactivation in BCG Russia occurred early and is in part responsible for its high degree of genomic stability, resulting in a substrain that has less genetic alterations than other vaccine substrains with respect to M. bovis AF2122/97 wild-type

Understanding Fatigue Within a Collegiate Aviation Program

Objective: The purpose of this study was fivefold: to investigate the symptoms that would prompt collegiate aviation pilots perceive they are fatigued; to investigate the time of the day they are most fatigued; to investigate their academic and personal schedules; to investigate the methods collegiate aviation pilots utilize to ensure they are fit to fly; and to investigate whether they have received any academic and/or flight fatigue identification and management training. Background: Fatigue is a pervasive safety hazard in aviation affecting several aspects of flight crew members’ ability to perform their job. Fatigue in aviation and its consequences has been researched across military and commercial operations, but until now Part 141 collegiate aviation pilots have been neglected. Method: Data were collected using an online survey questionnaire self-report questionnaire (N = 122) consisting of items investigating fatigue identification and management by Part 141 collegiate aviation pilots. Results: Sixty percent of the participants usually experience the mental and physical symptoms of fatigue during flight activities. A finding of concern was that 43% of the participants indicated they had not received any training in fatigue identification and management during ground and flight activities. Conclusion: The safety management of fatigue in a Part 141 collegiate aviation environment is a safety issue that warrants further research, and training and education

Fatigue In Collegiate Aviation

Flight training has received little attention in fatigue research. Only transfers of knowledge gained in commercial and military aviation have been applied to general aviation without bridging the gap to the training environment. The purpose of this study was to assess collegiate aviation students’ perceptions of lifestyle and mitigation strategies related to fatigue. Participants were recruited from a Midwestern university’s accredited Part 141 flight school and a partner fixed base operator (FBO). The researchers of this study used a survey questionnaire to gather quantitative and qualitative responses. The majority of participants (68%) had logged less than 250 flight hours and were under 25 years of age (93%). Many respondents (66%) reported fatigued stemming from sleep quantity or quality deficits. The primary fatigue contributing factors included an insufficient resting time and an inadequate work-free time balance. Daily free time activities conducive to healthy sleep patterns were frequently neglected. Furthermore, several other factors that affected participants’ lifestyles resulted from demands imposed by the college environment. A finding of concern was that half of the sample did not consider themselves to engage in fully adequate bodily exercise, nutritional habits, and workload or stress management. These areas, however, are prime considerations when working towards healthy sleep patterns. Lastly, the researchers presented recommendations for future research. Findings from this study can assist the general aviation community in gaining a greater understanding of how collegiate aviation students perceive, process, and manage the risk of fatigue in aviation

Fatigue Issues and Mitigation Strategies in Collegiate Aviation

The reduction of fatigue-related accidents has been in the NTSB most wanted list since 2016 (NSTB, 2019). Most research studies have focused on fatigue identification and management within the commercial and/or military aviation environments (Caldwell et al., 2009; Gawron, 2016; Sieberichs & Kluge, 2016). However, collegiate aviation may be the most challenging in terms of fatigue mitigation. Flight instructors and students often have schedules which may increase the risks for fatigue