Genetic counseling student demographics: an empirical comparison of two cohorts.

Genetic counseling student characteristics may be evolving with the expansion and diversification of the genetic counseling field. We compared characteristics and previously accrued experiences of genetic counseling students enrolled in the 2018-2019 academic year with genetic counseling students surveyed by Lega et al. (Journal of Genetic Counseling, 14, 395; 2005).

High-Throughput Screening at the Membrane Interface Reveals Inhibitors of Amyloid-β.

Aggregation and the formation of oligomeric intermediates of amyloid-β (Aβ) at the membrane interface of neuronal cells are implicated in the cellular toxicity and pathology of Alzheimer's disease. Small molecule compounds have been shown to suppress amyloid aggregation and cellular toxicity, but often the presence of a lipid membrane negates their activity. A high-throughput screen of 1800 small molecules was performed to search for membrane active inhibitors, and 21 primary hits were discovered.

Structural Interaction of Apolipoprotein A-I Mimetic Peptide with Amyloid-β Generates Toxic Hetero-oligomers.

Apolipoproteins are involved in pathological conditions of Alzheimer's disease (AD), and it has been reported that truncated apolipoprotein fragments and β-amyloid (Aβ) peptides coexist as neurotoxic heteromers within the plaques. Therefore, it is important to investigate these complexes at the molecular level to better understand their properties and roles in the pathology of AD. Here, we present a mechanistic insight into such heteromerization using a structurally homologue apolipoprotein fragment of apoA-I (4F) complexed with Aβ(M1-42) and characterize their toxicity.

A cationic polymethacrylate-copolymer acts as an agonist for β-amyloid and an antagonist for amylin fibrillation.

In humans, β-amyloid and islet amyloid polypeptide (IAPP, also known as amylin) aggregations are linked to Alzheimer's disease and type-2 diabetes, respectively. There is significant interest in better understanding the aggregation process by using chemical tools. Here, we show the ability of a cationic polymethacrylate-copolymer (PMAQA) to quickly induce a β-hairpin structure and accelerate the formation of amorphous aggregates of β-amyloid-1-40, whereas it constrains the conformational plasticity of amylin for several days and slows down its aggregation at substoichiometric polymer concentrations.

Alzheimer's amyloid-beta intermediates generated using polymer-nanodiscs.

Polymethacrylate-copolymer (PMA) encased lipid-nanodiscs (∼10 nm) and macro-nanodiscs (>15 nm) are used to study Aβ1-40 aggregation. We demonstrate that PMA-nanodiscs form a ternary association with Aβ and regulate its aggregation kinetics by trapping intermediates. Results demonstrating the reduced neurotoxicity of nanodisc-bound Aβ oligomers are also reported.

Fluorescence lifetime imaging of physiological free Cu(II) levels in live cells with a Cu(II)-selective carbonic anhydrase-based biosensor.

Copper is a required trace element that plays key roles in a number of human enzymes, such that copper deficiency or genetic defects in copper transport lead to serious or fatal disease. Rae, et al., had famously predicted that free copper ion levels in the cell cytoplasm were extremely low, typically too low to be observable.

Long wavelength fluorescence ratiometric zinc biosensor.

A protein-based emission ratiometric fluorescence biosensor is described that exhibits sensitivity to free zinc ion in solution down to picomolar concentrations. Ratiometric measurements are widely used to assure accurate quantitation, and emission ratios are preferred for laser scanning microscopes such as confocal fluorescence microscopes. The relatively long emission wavelengths used are well suited to studies in tissues and other matrices which exhibit significant fluorescence background, and the apo-carbonic anhydrase moiety recognizes zinc ion with high and controllable specificity.

Determination of zinc using carbonic anhydrase-based fluorescence biosensors.

This chapter summarizes the use of carbonic anhydrase (CA)-based fluorescent indicators to determine free zinc in solution, in cells, and in subcellular organelles. Expression (both in situ and in vitro) and preparation of CA-based indicators are described, together with techniques of their use, and procedures to minimize contamination. Recipes for zinc buffers are supplied.

Measuring picomolar intracellular exchangeable zinc in PC-12 cells using a ratiometric fluorescence biosensor.

Zinc plays both physiological and pathological roles in biology, making it of increasing interest. To date, intracellular free zinc has been measured in cell types supplemented with or enriched in zinc, such as hippocampal neurons. Here we quantitatively image intracellular exchangeable zinc in an ordinary resting cell culture line (PC-12), using an excitation ratiometric fluorescent biosensor based on carbonic anhydrase (CA).

A continuous fluorescent assay for protein prenyltransferases measuring diphosphate release.

Protein farnesyltransferase and protein geranylgeranyltransferase type I catalyze the transfer of a 15- and a 20-carbon prenyl group, respectively, from a prenyl diphosphate to a cysteine residue at the carboxyl terminus of target proteins, with the concomitant release of diphosphate. Common substrates include oncogenic Ras proteins, which are implicated in up to 30% of all human cancers, making prenyltransferases a viable target for chemotherapeutic drugs. A coupled assay has been developed to measure the rate constant of diphosphate (PPi) dissociation during the prenyltransferase reaction under both single and multiple turnover conditions.

DsRed as a highly sensitive, selective, and reversible fluorescence-based biosensor for both Cu(+) and Cu(2+) ions.

The wild type form of Red fluorescent protein (DsRed), an intrinsically fluorescent protein found in tropical corals, is found to be highly selective, reversible and sensitive for both Cu(+) and Cu(2+), with a nanomolar detection limit. The selectivity towards these ions is retained even in the presence of other heavy metal ions. The K(d) values for monovalent and divalent copper, based on single binding isotherms, are 450 and 540 nM, respectively.