Good guide, bad guide:spacer sequence-dependent cleavage efficiency of Cas12a

Genome editing has recently made a revolutionary development with the introduction of the CRISPR–Cas technology. The programmable CRISPR-associated Cas9 and Cas12a nucleases generate specific dsDNA breaks in the genome, after which host DNA-repair mechanisms can be manipulated to implement the desired editing. Despite this spectacular progress, the efficiency of Cas9/Cas12a-based engineering can still be improved. Here, we address the variation in guide-dependent efficiency of Cas12a, and set out to reveal the molecular basis of this phenomenon. We established a sensitive and robust in vivo targeting assay based on loss of a target plasmid encoding the red fluorescent protein (mRFP). Our results suggest that folding of both the precursor guide (pre-crRNA) and the mature guide (crRNA) have a major influence on Cas12a activity. Especially, base pairing of the direct repeat, other than with itself, was found to be detrimental to the activity of Cas12a. Furthermore, we describe different approaches to minimize base-pairing interactions between the direct repeat and the variable part of the guide. We show that design of the 3′ end of the guide, which is not involved in target strand base pairing, may result in substantial improvement of the guide's targeting potential and hence of its genome editing efficiency

Symmetry and topology in antiferromagnetic spintronics

Antiferromagnetic spintronics focuses on investigating and using antiferromagnets as active elements in spintronics structures. Last decade advances in relativistic spintronics led to the discovery of the staggered, current-induced field in antiferromagnets. The corresponding N\'{e}el spin-orbit torque allowed for efficient electrical switching of antiferromagnetic moments and, in combination with electrical readout, for the demonstration of experimental antiferromagnetic memory devices. In parallel, the anomalous Hall effect was predicted and subsequently observed in antiferromagnets. A new field of spintronics based on antiferromagnets has emerged. We will focus here on the introduction into the most significant discoveries which shaped the field together with a more recent spin-off focusing on combining antiferromagnetic spintronics with topological effects, such as antiferromagnetic topological semimetals and insulators, and the interplay of antiferromagnetism, topology, and superconductivity in heterostructures.Comment: Book chapte

Multiband tight-binding theory of disordered ABC semiconductor quantum dots: Application to the optical properties of alloyed CdZnSe nanocrystals

Zero-dimensional nanocrystals, as obtained by chemical synthesis, offer a broad range of applications, as their spectrum and thus their excitation gap can be tailored by variation of their size. Additionally, nanocrystals of the type ABC can be realized by alloying of two pure compound semiconductor materials AC and BC, which allows for a continuous tuning of their absorption and emission spectrum with the concentration x. We use the single-particle energies and wave functions calculated from a multiband sp^3 empirical tight-binding model in combination with the configuration interaction scheme to calculate the optical properties of CdZnSe nanocrystals with a spherical shape. In contrast to common mean-field approaches like the virtual crystal approximation (VCA), we treat the disorder on a microscopic level by taking into account a finite number of realizations for each size and concentration. We then compare the results for the optical properties with recent experimental data and calculate the optical bowing coefficient for further sizes

Era Baru Kesehatan Mental Indonesia: Sebuah Kisah Dari Desa Siaga Sehat Jiwa (DSSJ)

Due to the large number of people with mental illness in Indonesia, traditional treatment to individuals with mental disorder becomes less effective. Community-based mental health treatment becomes a more effective and efficient choice in handling the disorder. Desa Siaga Sehat Jiwa (DSSJ, Mental Health Awareness Village) has comes as a form of community-based mental health treatment. One of villages in Yogyakarta where the program has been being implemented is in Selomartani village, Kalasan Sub-district, Sleman Regency. This study aimed to look at the process of formation, implementation and obstacles of the program in this village, and to provide advice or suggestions for its improvement. This study used a qualitative approach with narrative method. Data were retrieved through interviews and focus group discussions. Participants involved in the study were 19 cadres of the program. Results obtained from the study indicated that cadres have ability in understanding clearly the system and their roles in the program and they know the consequences of being a cadre of DSSJ. The new finding obtained during the research process was the emergence of "compassion fatigue” or “secondary traumatic stress", a traumatic disorder suffered by the cadre while handling patients. Keywords: community-based mental health, compassion fatigue, Mental Health Awareness Villag

Interview with Marjorie Harkins Buchanan Kiewit

In this interview with Julia Stringfellow, Marjorie Harkins Buchanan Kiewit, LU class of 1943, discusses her time as a student as well as her time on the Board of Trustees.https://lux.lawrence.edu/oralhistories/1036/thumbnail.jp

A Requirement of TolC and MDR Efflux Pumps for Acid Adaptation and GadAB Induction in Escherichia coli

BACKGROUND: The TolC outer membrane channel is a key component of several multidrug resistance (MDR) efflux pumps driven by H(+) transport in Escherichia coli. While tolC expression is under the regulation of the EvgA-Gad acid resistance regulon, the role of TolC in growth at low pH and extreme-acid survival is unknown. METHODS AND PRINCIPAL FINDINGS: TolC was required for extreme-acid survival (pH 2) of strain W3110 grown aerobically to stationary phase. A tolC deletion decreased extreme-acid survival (acid resistance) of aerated pH 7.0-grown cells by 10(5)-fold and of pH 5.5-grown cells by 10-fold. The requirement was specific for acid resistance since a tolC defect had no effect on aerobic survival in extreme base (pH 10). TolC was required for expression of glutamate decarboxylase (GadA, GadB), a key component of glutamate-dependent acid resistance (Gad). TolC was also required for maximal exponential growth of E. coli K-12 W3110, in LBK medium buffered at pH 4.5-6.0, but not at pH 6.5-8.5. The TolC growth requirement in moderate acid was independent of Gad. TolC-associated pump components EmrB and MdtB contributed to survival in extreme acid (pH 2), but were not required for growth at pH 5. A mutant lacking the known TolC-associated efflux pumps (acrB, acrD, emrB, emrY, macB, mdtC, mdtF, acrEF) showed no growth defect at acidic pH and a relatively small decrease in extreme-acid survival when pre-grown at pH 5.5. CONCLUSIONS: TolC and proton-driven MDR efflux pump components EmrB and MdtB contribute to E. coli survival in extreme acid and TolC is required for maximal growth rates below pH 6.5. The TolC enhancement of extreme-acid survival includes Gad induction, but TolC-dependent growth rates below pH 6.5 do not involve Gad. That MDR resistance can enhance growth and survival in acid is an important consideration for enteric organisms passing through the acidic stomach

GaSbBi alloys and heterostructures: fabrication and properties

International audienceDilute bismuth (Bi) III-V alloys have recently attracted great attention, due to their properties of band-gap reduction and spin-orbit splitting. The incorporation of Bi into antimonide based III-V semiconductors is very attractive for the development of new optoelectronic devices working in the mid-infrared range (2-5 µm). However, due to its large size, Bi does not readily incorporate into III-V alloys and the epitaxy of III-V dilute bismides is thus very challenging. This book chapter presents the most recent developments in the epitaxy and characterization of GaSbBi alloys and heterostructures

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe