The ability to introduce different biophysical probes into defined positions in target proteins will provide powerful approaches for interrogating protein structure, function and dynamics. However, methods for site-specifically incorporating multiple distinct unnatural amino acids are hampered by their low efficiency. Here we provide a general solution to this challenge by developing an optimized orthogonal translation system that uses amber and evolved quadruplet-decoding transfer RNAs to encode numerous pairs of distinct unnatural amino acids into a single protein expressed in Escherichia coli with a substantial increase in efficiency over previous methods.
View Article and Find Full Text PDFA new cyclic tetrapeptide, cyclo-(L-leucyl-trans-4-hydroxy-L-prolyl-D-leucyl-trans-4-hydroxy-L-proline) (1), was isolated from the co-culture broth of two mangrove fungi Phomopsis sp. K38 and Alternaria sp. E33.
View Article and Find Full Text PDFSmall conductance Ca(2+)-sensitive potassium (SK2) channels are voltage-independent, Ca(2+)-activated ion channels that conduct potassium cations and thereby modulate the intrinsic excitability and synaptic transmission of neurons and sensory hair cells. In the cochlea, SK2 channels are functionally coupled to the highly Ca(2+) permeant α9/10-nicotinic acetylcholine receptors (nAChRs) at olivocochlear postsynaptic sites. SK2 activation leads to outer hair cell hyperpolarization and frequency-selective suppression of afferent sound transmission.
View Article and Find Full Text PDFBoth mass (as a measure of body reserves) during breeding and adult survival should reflect variation in food availability. Those species that are adapted to less seasonally variable foraging niches and so where competition dominates during breeding, will tend to have a higher mass increase via an interrupted foraging response, because their foraging demands increase and so become more unpredictable. They will then produce few offspring per breeding attempt, but trade this off with higher adult survival.
View Article and Find Full Text PDFBackground And Objective: Congenital myasthenic syndromes are rare inherited disorders characterized by fatigable weakness caused by malfunction of the neuromuscular junction. We performed whole exome sequencing to unravel the genetic aetiology in an English sib pair with clinical features suggestive of congenital myasthenia.
Methods: We used homozygosity mapping and whole exome sequencing to identify the candidate gene variants.
Research on the role of behavior change as an efficacious intervention for adults with type 2 diabetes is evolving. Searching PubMed and Ovid Medline, we identified and reviewed primarily randomized controlled trials from 2010 to 2013 of adults managing type 2 diabetes without insulin. All studies are evaluated in terms of the rigor of their design and their impact on glycosylated hemoglobin.
View Article and Find Full Text PDFBackground: Neurons are one of the most structurally and functionally diverse cell types found in nature, owing in large part to their unique class specific dendritic architectures. Dendrites, being highly specialized in receiving and processing neuronal signals, play a key role in the formation of functional neural circuits. Hence, in order to understand the emergence and assembly of a complex nervous system, it is critical to understand the molecular mechanisms that direct class specific dendritogenesis.
View Article and Find Full Text PDFDendrite development is crucial in the formation of functional neural networks. Recent studies have provided insights into the involvement of secretory transport in dendritogenesis, raising the question of how the secretory pathway is controlled to direct dendritic elaboration. Here, we identify a functional link between transcriptional regulatory programs and the COPII secretory machinery in driving dendrite morphogenesis in Drosophila dendritic arborization (da) sensory neurons.
View Article and Find Full Text PDFDiabetes affects over 25 million people in the United States, most of whom are over the age of 16 and many of whom are licensed to drive a motor vehicle. Safe operation of a motor vehicle requires complex interactions of cognitive and motor functions and medical conditions that affect these functions often will increase the risk of motor vehicle accidents (MVA). In the case of diabetes, hypoglycemia is the most common factor that has been shown to increase MVA rates.
View Article and Find Full Text PDFThe numbers and types of ionotropic glutamate receptors at most vertebrate central excitatory synapses are altered as a function of changes in input activity patterns that occur during postnatal development. Activity-dependent developmental alterations in glutamate receptors underlie lasting changes in synaptic efficacy (plasticity) and metaplasticity (the plasticity of synaptic plasticity), which are critical elements of normal brain maturation. Understanding the specific involvement of glutamate receptors in synaptic development and function is made multiplicatively complex by the existence of a large number of glutamate receptor subunits, numerous subunit-specific amino acid sequences that regulate receptor function, and subunit-specific synaptic insertion restrictions imposed by associated anchoring proteins.
View Article and Find Full Text PDFObjective: This study compared video recordings from routine driving of ADHD and non-ADHD young adults to identify differences in driving behaviors.
Method: A matched sample of young adult drivers with and without ADHD are compared via blinded ratings of videoed g-force events recorded by DriveCam technology over 3 months of on-road driving.
Results: ADHD drivers were significantly more likely to have more crashes, minor events, and g-force events.
Dopamine neurotransmission accounts for a number of important brain functions across species including memory formation, the anticipation of reward, cognitive facilities, and drug addiction. Despite this functional significance, relatively little is known of the cellular pathways associated with drug-induced molecular adaptations within individual neurons. Due to its genetic tractability, simplicity, and economy of scale, Drosophila melanogaster has become an important tool in the study of neurological disease states, including drug addiction.
View Article and Find Full Text PDFWe examined the structure and biomineralization of prismatic magnetosomes in the magnetotactic marine vibrio Magnetovibrio blakemorei strain MV-1 and a non-magnetotactic mutant derived from it, using a combination of cryo-electron tomography and freeze-fracture. The vesicles enveloping the Magnetovibrio magnetosomes were elongated and detached from the cell membrane. Magnetosome crystal formation appeared to be initiated at a nucleation site on the membrane inner surface.
View Article and Find Full Text PDFThe management of pediatric and adolescent patients with pure aortic valve regurgitation remains challenging and controversial (Christos et al., Eur J Cardiothorac Surg 17:125-133, 2000; Gersony and Sommerville, ACC Curr J Rev 31:97-98, 2000; Hasaniya et al., J Thorac Cardiovasc Surg 127:970-974, 2004; Sabet et al.
View Article and Find Full Text PDFObjective: To address a major barrier of medication noncompliance for individuals with ADHD, the authors present the ADHD Medication Attitude Scale (AMAS) with initial psychometric analyses and discriminant validity data.
Method: The AMAS was posted on ADHD websites, along with questions about demographics and medication usage over a 6-month period. A total of 356 ADHD respondents qualified for data analysis (160 males, 196 females, mean age = 18.
Am J Physiol Gastrointest Liver Physiol
October 2012
Cathepsins regulate premature trypsinogen activation within acinar cells, a key initial step in pancreatitis. The identity, origin, and causative roles of activated cathepsins in pancreatic inflammation and pain are not defined. By using a near infrared-labeled activity-based probe (GB123) that covalently modifies active cathepsins, we localized and identified activated cathepsins in mice with cerulein-induced pancreatitis and in pancreatic juice from patients with chronic pancreatitis.
View Article and Find Full Text PDFVegetation at the aquatic-terrestrial interface can alter landscape features through its growth and interactions with sediment and fluids. Even similar species may impart different effects due to variation in their interactions and feedbacks with the environment. Consequently, replacement of one engineering species by another can cause significant change in the physical environment.
View Article and Find Full Text PDFBackground: Thrombin-dependent platelet activation is heightened in the setting of percutaneous coronary intervention and may cause arterial thrombosis with consequent myocardial necrosis. Given the high incidence of adverse effects in patients with acute coronary syndromes, there remains an unmet need for the development of new therapeutics that target platelet activation without unduly affecting hemostasis. The thrombin receptor, PAR1, has recently emerged as a promising new target for therapeutic intervention in patients with acute coronary syndromes.
View Article and Find Full Text PDFRapid, site-specific labeling of proteins with diverse probes remains an outstanding challenge for chemical biologists. Enzyme-mediated labeling approaches may be rapid but use protein or peptide fusions that introduce perturbations into the protein under study and may limit the sites that can be labeled, while many "bioorthogonal" reactions for which a component can be genetically encoded are too slow to effect quantitative site-specific labeling of proteins on a time scale that is useful for studying many biological processes. We report a fluorogenic reaction between bicyclo[6.
View Article and Find Full Text PDFDriving is a dangerous activity for adolescents, perhaps being even more precarious for adolescents with type 1 diabetes due to the possibility of extreme blood glucose (BG). There is no available data on adolescent driving safety concerns and type 1 diabetes. To begin addressing this issue, we surveyed parents regarding their observations and concerns.
View Article and Find Full Text PDFThe left-handed β-helix (LHBH) is an intriguing, rare structural pattern in polypeptides that has been implicated in the formation of amyloid aggregates. We used accurate all-atom replica-exchange molecular dynamics (REMD) simulations to study the relative stability of diverse sequences in the LHBH conformation. Ensemble-average coordinates from REMD served as a scoring criterion to identify sequences and threadings optimally suited to the LHBH, as in a fold recognition paradigm.
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