259 research outputs found
A Conditionally Fluorescent Peptide Reporter of Secondary Structure Modulation
Proteins containing intrinsic disorder often form secondary structure upon interaction with a binding partner. Modulating such structures presents an approach for manipulating the resultant functional outcomes. Translational repressor protein 4E‐BP1 is an example of an intrinsically disordered protein that forms an α‐helix upon binding to its protein ligand, eIF4E. Current biophysical methods for analyzing binding‐induced structural changes are low‐throughput, require large amounts of sample, or are extremely sensitive to signal interference by the ligand itself. Herein, we describe the discovery and development of a conditionally fluorescent 4E‐BP1 peptide that reports structural changes of its helix in high‐throughput format. This reporter peptide is based on conditional quenching of fluorescein by thioamides. In this case, fluorescence signal increases as the peptide becomes more ordered. Conversely, destabilization of the α‐helix results in decreased fluorescence signal. The low concentration and low volume of peptide required make this approach amenable for high‐throughput screening to discover ligands that alter peptide secondary structure.PET lights up peptide dynamics: Photoinduced electron transfer (PET) quenching of fluorescence by thioamides presents an elegant method for monitoring changes in macromolecular conformation. Here we apply this approach to monitor peptide dynamics in a 384‐well plate format. Using a fluorescein‐conjugated, 4E‐BP1‐based peptide containing an embedded thioamide, we probe its transition from disorder to a short α‐helix.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146852/1/cbic201800377.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146852/2/cbic201800377-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146852/3/cbic201800377_am.pd
Optimizing Neutron Yield for Active Interrogation
Neutrons are commonly used for many applications, including active interrogation and cancer therapy. One critical aspect for active interrogation efficiency is neutron yield, which is more important for successful resolution than the energy spectrum. The typical approach for improving neutron yield entails producing more neutrons, which has motivated multiple studies using the interaction of increasingly more powerful tabletop lasers with plastic targets to generate protons or deuterons that are absorbed by another target to create neutrons [1]. Alternatively, one may use lenses to focus the neutrons to increase yield rather than simply generating more neutrons with more powerful lasers [2]. Assessing either approach requires a comprehensive model simulating neutron generation and transport to optimize the target material, system geometry, and neutron yield. A complete model from laser source to neutron generation is beyond the scope of the current study, so this project focuses on simulating the interaction of deuterons with typical target materials, such as lithium or beryllium. We use the neutron transport code Monte Carlo N-Particles (MCNP), which applies the Monte Carlo method to track particles [3]. The simulations accurately reflected experimental results from several groups [4]. Future analyses will assess improvements in neutron yield and directionality through strategically incorporating neutron lenses
Rapid diagnostic tests for diagnosing uncomplicated non-falciparum or Plasmodium vivax malaria in endemic countries
Background
In settings where both Plasmodium vivax and Plasmodium falciparum infection cause malaria, rapid diagnostic tests (RDTs) need to distinguish which species is causing the patients' symptoms, as different treatments are required. Older RDTs incorporated two test lines to distinguish malaria due to P. falciparum, from malaria due to any other Plasmodium species (non-falciparum). These RDTs can be classified according to which antibodies they use: Type 2 RDTs use HRP-2 (for P. falciparum) and aldolase (all species); Type 3 RDTs use HRP-2 (for P. falciparum) and pLDH (all species); Type 4 use pLDH (fromP. falciparum) and pLDH (all species).
More recently, RDTs have been developed to distinguish P. vivax parasitaemia by utilizing a pLDH antibody specific to P. vivax.
Objectives
To assess the diagnostic accuracy of RDTs for detecting non-falciparum or P. vivax parasitaemia in people living in malaria-endemic areas who present to ambulatory healthcare facilities with symptoms suggestive of malaria, and to identify which types and brands of commercial test best detect non-falciparum and P. vivax malaria.
Search methods
We undertook a comprehensive search of the following databases up to 31 December 2013: Cochrane Infectious Diseases Group Specialized Register; MEDLINE; EMBASE; MEDION; Science Citation Index; Web of Knowledge; African Index Medicus; LILACS; and IndMED.
Selection criteria
Studies comparing RDTs with a reference standard (microscopy or polymerase chain reaction) in blood samples from a random or consecutive series of patients attending ambulatory health facilities with symptoms suggestive of malaria in non-falciparum endemic areas.
Data collection and analysis
For each study, two review authors independently extracted a standard set of data using a tailored data extraction form. We grouped comparisons by type of RDT (defined by the combinations of antibodies used), and combined in meta-analysis where appropriate. Average sensitivities and specificities are presented alongside 95% confidence intervals (95% CI).
Main results
We included 47 studies enrolling 22,862 participants. Patient characteristics, sampling methods and reference standard methods were poorly reported in most studies.
RDTs detecting 'non-falciparum' parasitaemia
Eleven studies evaluated Type 2 tests compared with microscopy, 25 evaluated Type 3 tests, and 11 evaluated Type 4 tests. In meta-analyses, average sensitivities and specificities were 78% (95% CI 73% to 82%) and 99% (95% CI 97% to 99%) for Type 2 tests, 78% (95% CI 69% to 84%) and 99% (95% CI 98% to 99%) for Type 3 tests, and 89% (95% CI 79% to 95%) and 98% (95% CI 97% to 99%) for Type 4 tests, respectively. Type 4 tests were more sensitive than both Type 2 (P = 0.01) and Type 3 tests (P = 0.03).
Five studies compared Type 3 tests with PCR; in meta-analysis, the average sensitivity and specificity were 81% (95% CI 72% to 88%) and 99% (95% CI 97% to 99%) respectively.
RDTs detecting P.vivax parasitaemia
Eight studies compared pLDH tests to microscopy; the average sensitivity and specificity were 95% (95% CI 86% to 99%) and 99% (95% CI 99% to 100%), respectively.
Authors' conclusions
RDTs designed to detect P. vivax specifically, whether alone or as part of a mixed infection, appear to be more accurate than older tests designed to distinguish P. falciparum malaria from non-falciparum malaria. Compared to microscopy, these tests fail to detect around 5% ofP. vivax cases. This Cochrane Review, in combination with other published information about in vitro test performance and stability in the field, can assist policy-makers to choose between the available RDTs
An Unexpected Stereochemical Insignificance Discovered in \u3cem\u3eAcinetobacter baumannii\u3c/em\u3e Quorum Sensing
Stereochemistry is a key aspect of molecular recognition for biological systems. As such, receptors and enzymes are often highly stereospecific, only recognizing one stereoisomer of a ligand. Recently, the quorum sensing signaling molecules used by the nosocomial opportunistic pathogen, Acinetobacter baumannii, were identified, and the primary signaling molecule isolated from this species was N-(3-hydroxydodecanoyl)-l-homoserine lactone. A plethora of bacterial species have been demonstrated to utilize 3-hydroxy-acylhomoserine lactone autoinducers, and in virtually all cases, the (R)-stereoisomer was identified as the natural ligand and exhibited greater autoinducer activity than the corresponding (S)-stereoisomer. Using chemical synthesis and biochemical assays, we have uncovered a case of stereochemical insignificance in A. baumannii and provide a unique example where stereochemistry appears nonessential for acylhomoserine lactone-mediated quorum sensing signaling. Based on previously reported phylogenetic studies, we suggest that A. baumannii has evolutionarily adopted this unique, yet promiscuous quorum sensing system to ensure its survival, particularly in the presence of other proteobacteria
Parental bonding and eating disorders: a systematic review
This article systematically reviewed studies of parental bonding in people with eating disorders. MEDLINE, PsychINFO, EMBASE and CINAHL were searched to identify studies that compared parental bonding in people diagnosed with an eating disorder relative to non-clinical controls. Twenty-four studies were identified. Women with eating disorders typically reported lower parental care and higher parental protection compared to non-clinical, but not psychiatric, controls. Interestingly, a modest number of studies found that these relationships were mediated by avoidant problem solving style and several schemas from the Young Schema Questionnaire (YSQ; Schmidt, Joiner, Young, & Telch, 1995). While there are methodological limitations associated with the reviewed studies, they do offer some support for the proposal that difficulties in parent-child relationships predispose women to eating disorders and other psychiatric diagnoses
Correction to:Expression of mitochondrial protein genes encoded by nuclear and mitochondrial genomes correlate with energy metabolism in dairy cattle
Stereochemical Insignificance Discovered in Acinetobacter baumannii Quorum Sensing
Stereochemistry is a key aspect of molecular recognition for biological systems. As such, receptors and enzymes are often highly stereospecific, only recognizing one stereoisomer of a ligand. Recently, the quorum sensing signaling molecules used by the nosocomial opportunistic pathogen, Acinetobacter baumannii, were identified, and the primary signaling molecule isolated from this species was N-(3-hydroxydodecanoyl)-l-homoserine lactone. A plethora of bacterial species have been demonstrated to utilize 3-hydroxy-acylhomoserine lactone autoinducers, and in virtually all cases, the (R)-stereoisomer was identified as the natural ligand and exhibited greater autoinducer activity than the corresponding (S)-stereoisomer. Using chemical synthesis and biochemical assays, we have uncovered a case of stereochemical insignificance in A. baumannii and provide a unique example where stereochemistry appears nonessential for acylhomoserine lactone-mediated quorum sensing signaling. Based on previously reported phylogenetic studies, we suggest that A. baumannii has evolutionarily adopted this unique, yet promiscuous quorum sensing system to ensure its survival, particularly in the presence of other proteobacteria
Enhancing volunteer engagement to achieve desirable outcomes: what can non-profit employers do?
Abstract Engagement is a positive psychological state that is linked with a range of beneficial individual and organizational outcomes. However, the factors associated with volunteer engagement have rarely been examined. Data from 1064 volunteers of a wildlife charity in the United Kingdom revealed that both task- and emotion-oriented
organizational support were positively related to volunteer engagement, and volunteer engagement was positively related to volunteer happiness and perceived social worth and negatively related to intent to leave the voluntary organization.
Consistent with theory, engagement acted as a mediator between these factors. The implications for future research and the relevance of the findings for voluntary organizations are discussed
Targeting the Wolbachia Cell Division Protein FtsZ as a New Approach for Antifilarial Therapy
Filarial nematode parasites are responsible for a number of devastating diseases in humans and animals. These include lymphatic filariasis and onchocerciasis that afflict 150 million people in the tropics and threaten the health of over one billion. The parasites possess intracellular bacteria, Wolbachia, which are needed for worm survival. Clearance of these bacteria with certain antibiotics leads to parasite death. These findings have pioneered the approach of using antibiotics to treat and control filarial infections. In the present study, we have investigated the cell division process in Wolbachia for new drug target discovery. We have identified the essential cell division protein FtsZ, which has a GTPase activity, as an attractive Wolbachia drug target. We describe the molecular characterization and catalytic properties of the enzyme and demonstrate that the GTPase activity is inhibited by the natural product, berberine, and small molecule inhibitors identified from a high-throughput screen. We also found that berberine was effective in reducing motility and reproduction in B. malayi parasites in vitro. Our results should facilitate the discovery of selective inhibitors of FtsZ as a novel antibiotic approach for controlling filarial infection
A Historiometric Examination of Machiavellianism and a New Taxonomy of Leadership
Although researchers have extensively examined the relationship between charismatic leadership and Machiavellianism (Deluga, 2001; Gardner & Avolio, 1995; House & Howell, 1992), there has been a lack of investigation of Machiavellianism in relation to alternative forms of outstanding leadership. Thus, the purpose of this investigation was to examine the relationship between Machiavellianism and a new taxonomy of outstanding leadership comprised of charismatic, ideological, and pragmatic leaders. Using an historiometric approach, raters assessed Machiavellianism via the communications of 120 outstanding leaders in organizations across the domains of business, political, military, and religious institutions. Academic biographies were used to assess twelve general performance measures as well as twelve general controls and five communication specific controls. The results indicated that differing levels of Machiavellianism is evidenced across the differing leader types as well as differing leader orientation. Additionally, Machiavellianism appears negatively related to performance, though less so when type and orientation are taken into account.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
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