An ER-peroxisome tether exerts peroxisome population control in yeast.

Eukaryotic cells compartmentalize biochemical reactions into membrane-enclosed organelles that must be faithfully propagated from one cell generation to the next. Transport and retention processes balance the partitioning of organelles between mother and daughter cells. Here we report the identification of an ER-peroxisome tether that links peroxisomes to the ER and ensures peroxisome population control in the yeast Saccharomyces cerevisiae. The tether consists of the peroxisome biogenic protein, Pex3p, and the peroxisome inheritance factor, Inp1p. Inp1p bridges the two compartments by acting as a molecular hinge between ER-bound Pex3p and peroxisomal Pex3p. Asymmetric peroxisome division leads to the formation of Inp1p-containing anchored peroxisomes and Inp1p-deficient mobile peroxisomes that segregate to the bud. While peroxisomes in mother cells are not released from tethering, de novo formation of tethers in the bud assists in the directionality of peroxisome transfer. Peroxisomes are thus stably maintained over generations of cells through their continued interaction with tethers.

Metal-enhanced fluorescence and FRET on nanohole arrays excited at angled incidence.

The influence of experimental parameters on the performance of plasmonic sensors is of great importance in analytical sciences. The plasmon coupling conditions (angle of incidence, metal composition, laser frequency and excitation/emission properties of fluorophores) were thus investigated for surface plasmon-enhanced fluorescence on metallic nanohole arrays. Optimal fluorescence enhancements were achieved when the plasmon resonance, the excitation laser and the fluorophore's excitation wavelengths were matched. The enhancement of the acceptor emission of a rhodamine 6G(Rh6G)-Quasar670™ FRET pair was achieved on the nanohole arrays by tuning the plasmon wavelength with the maximal overlap of the donor's emission and acceptor excitation. Silver nanohole arrays achieved larger fluorescence enhancement than gold nanohole arrays at 532 nm, while gold nanohole arrays led to larger fluorescence enhancement at 635 nm. These results demonstrate the importance of tuning the plasmon coupling conditions for surface plasmon-enhanced fluorescence sensing.

Plasmonic nanopipette biosensor.

Integrating a SERS immunoassay on a plasmonic "patch clamp" nanopipette enabled nanobiosensing for the detection of IgG. A SERS response was obtained using a sandwich assay benefiting from plasmon coupling between a capture Au nanoparticle (AuNP) on a nanotip and a second AuNP modified with a Raman active reporter and an antibody selective for IgG. The impact of nanoparticle shape and surface coverage was investigated alongside the choice of Raman active reporter, deposition pH, and plasmonic coupling, in an attempt to fully understand the plasmonic properties of nanopipettes and to optimize the nanobiosensor for the detection of IgG. These probes will find applications in various fields due to their nanoscale size leading to the possibility of spatially and temporally addressing their location near cells to monitor secretion of biomolecules.

Angle-dependent resonance of localized and propagating surface plasmons in microhole arrays for enhanced biosensing.

The presence of microhole arrays in thin Au films is suited for the excitation of localized and propagating surface plasmon (SP) modes. Conditions can be established to excite a resonance between the localized and propagating SP modes, which further enhanced the local electromagnetic (EM) field. The co-excitation of localized and propagating SP modes depends on the angle of incidence (θ(exc)) and refractive index of the solution interrogated. As a consequence of the enhanced EM field, enhanced sensitivity and an improved response for binding events by about a factor of 3 to 5 was observed with SPR sensors in the Kretschmann configuration for a set of experimental conditions (λ(SPR), θ(exc), and η). Thus, microhole arrays can improve sensing applications of SPR based on classical prism-based instrumentation and are suited for SP-coupled spectroscopic techniques.

Optical sensor for diverse organic vapors at ppm concentration ranges.

A broadly responsive optical organic vapor sensor is described that responds to low concentrations of organic vapors without significant interference from water vapor. Responses to several classes of organic vapors are highlighted, and trends within classes are presented. The relationship between molecular properties (vapor pressure, boiling point, polarizability, and refractive index) and sensor response are discussed.

Visual indicator for trace organic volatiles.

We describe herein a novel approach for visual indication of trace organic vapors. The sensor utilizes a microporous material within a visual thin film transducer to produce changes in color upon exposure to a very wide range of volatile organic compounds. Visual indication at 5 parts per million (ppm) is demonstrated, with optoelectronic detection achieved to below 50 parts per billion (ppb). Through a thoughtful design of the sensor, we are able to avoid interference from water vapor, a critical attribute needed for practical application.

Cyanotoxin release from the benthic, mat-forming cyanobacterium Microseira (Lyngbya) wollei in the St. Lawrence River, Canada.

Benthic cyanobacterial mats occurring in the St. Lawrence River fluvial lakes Saint-Louis and Saint-Pierre are dominated by Microseira (Lyngbya) wollei which produce several cyanotoxins including LWTX-1 that is characteristic of Microseira wollei. This cyanotoxin is not only present in the filaments forming benthic mats, but was also measured in the water overlying the mats. LWTX-1 was found in all cyanobacterial filament samples (75.29-103.26 ng mg-1) and all overlying water samples (3.01-11.03 ng L-1). Toxin concentrations measured in overlying water and dry biomass were strongly correlated (r = 0.94). Furthermore, LWTX-1 concentration in water was positively correlated with the dissolved organic carbon in water (r = 0.74) and % nitrogen content in cyanobacterial filaments (r = 0.52). A preliminary study was conducted to determine the release and degradation rates of LWTX-1 from a M. wollei mat kept under laboratory conditions over a 3-month period. Toxin measurements revealed an early, massive toxin release followed by a typical decaying function, with a half-life in the order of 17 days. Our results raise concerns about the occurrence and downstream advection of dissolved cyanotoxins from Microseira mats in the aquatic environment. Graphical abstract.

Impact of a pharmacist-directed pain management service on inpatient opioid use, pain control, and patient safety.

PURPOSE: To evaluate the impact of a pharmacy-directed pain management service (PPMS) designed to optimize analgesic pharmacotherapy, minimize adverse events, and improve patients' experience of pain management. METHODS: A retrospective analysis was conducted to evaluate the PPMS consisting of 3 dedicated pain management clinical pharmacists who perform both consult-based and stewardship functions. Multiple measures of opioid use and associated patient satisfaction outcomes during 3-year periods before and after implementation of the PPMS were compared. RESULTS: Significant decreases in use of institutionally defined high-risk opioid medications (e.g., parenteral hydromorphone, fentanyl, transdermal fentanyl patches), a decrease in total institutional opioid use, increased coanalgesic and adjunctive medication use, and a decrease in rapid response team (RRT) and code blue events associated with opioid-induced oversedation were seen after service implementation. Despite decreased opioid use, available patient satisfaction data suggested ongoing improvement in associated Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey domains. CONCLUSION: Our data highlights the impact of a pharmacy directed pain management service on institutional opioid use with available data suggesting improved patient satisfaction scores and indirect cost savings. Despite decreased opioid use, available patient satisfaction data suggested ongoing improvement in associated HCAHPS survey pain management domains.

Protective effect of Cox-2 allelic variants on risk of colorectal adenoma development in African Americans.

BACKGROUND: Recent evidence indicates that single nucleotide polymorphisms (SNPs) in the Cox-2 gene may modulate the risk of colorectal adenoma development. PATIENTS AND METHODS: We explored possible associations between Cox-2 polymorphisms and risk of adenoma development in an African American case-control study comprising 72 cases of advanced adenomas and 146 polyp-free controls. An exhaustive approach of genotyping 13 haplotype-tagging SNPs (ht SNPs) distributed over the entire COX-2 gene was used. RESULTS: Statistically significant inverse associations were observed between the heterozygous genotypes at the 5229 G>T polymorphism in intron 5 [odds ratio (OR)=0.42; confidence interval (CI)=0.19-0.92; p=0.03] and at the 10935 A>G polymorphism in the 3' flanking region downstream from the poly A signals (OR=0.39; CI=0.18-0.83;p=0.01) and the risk for colorectal adenoma development. CONCLUSION: The data from our pilot study suggest that allelic variants of the COX-2 gene significantly influence the risk of adenoma development in the African American population.

Single chip SPR and fluorescent ELISA assay of prostate specific antigen.

A multi-channel system combining fluidics and micropatterned plasmonic materials with wavelength interrogation surface plasmon resonance (SPR) and fluorescence detection was integrated from the combination of a small and motorized fluorescence microscope mounted on a portable 4-channel SPR instrument. The SPR and fluorescent measurements were performed based on the same detection area in a multi-channel fluidic, with a sensing scheme for prostate-specific antigen (PSA) consisting of a sandwich assay with a capture anti-PSA immobilized onto the SPR sensor and a detection anti-PSA modified with horseradish peroxidase (HRP). In this dual-detection instrument, fluorescence was measured from the solution side of the micropatterned gold film, while the interface between the glass prism and the gold film served to interrogate the SPR response. The SPR sensors were comprised of microhole arrays fabricated by photolithography to enhance the instrumental response for PSA detection by approximately a factor of 2 to 3 and they were coated with a self-assembled monolayer of a peptide (3-MPA-HHHDD-OH) to minimize nonspecific adsorption. PSA was successfully detected at clinical concentrations from 10 pM to 50 nM with this integrated system in a single assay lasting 12 minutes, almost centering on the desired range for PSA diagnostic tests (>4 ng mL(-1) or >150 pM). The combination of two robust techniques in a single chip and instrument has led to a simple and effective assay that can be carried out on a small and portable instrument providing rapid biodetection of an important cancer biomarker with a dynamic range of nearly 4 orders of magnitude in the clinical range.

Tuning the 3D plasmon field of nanohole arrays.

Modern photonics is being revolutionized through the use of nanostructured plasmonic materials, which confine light to sub-diffraction limit resolution providing universal, sensitive, and simple transducers for molecular sensors. Understanding the mechanisms by which light interacts with plasmonic crystals is essential for developing application-focussed devices. The strong influence of grating coupling on electromagnetic field distribution, frequency and degeneracy of plasmon bands has now been characterized using hexagonal nanohole arrays. An equation for nanohole arrays was derived to demonstrate the strong influence of incidence and rotation angle on optical properties of 2D plasmonic crystals such as nanohole arrays. Consequently, we report experimental data that are in strong agreement with finite difference time-domain (FDTD) simulations that clearly demonstrate the influence of the grating coupling conditions on the optical properties (such as plasmon degeneracy and bandwidth), and on the distribution of the plasmon field around nanohole arrays (including tuneable penetration depths and highly localized fields). The tuneable 3D plasmon field allowed for controlled sensing properties and by increasing the angle of incidence to 30 degrees, the resonance wavelength was tuned from 1000 to 600 nm, and the sensitivity was enhanced by nearly 300% for a protein assay using surface plasmon resonance (SPR) and by 40% with surface-enhanced Raman scattering (SERS) sensors.

Identification of a potential pharmacological sanctuary for HIV type 1 in a fraction of CD4(+) primary cells.

We have identified a subset of HIV-susceptible CD4(+)CCR5(+) cells in human PBMCs that can efficiently exclude protease inhibitors (PI) due to high P-glycoprotein (P-gp) efflux activity. Phenotypically these cells are heterogeneous, include both T and non-T cells, and some display markers of memory cells. Cells with high P-gp represent 16-56% (median = 37.3) of all CD4(+)CCR5(+) cells in healthy donors, and are selectively depleted in HIV-1-infected individuals (4.1-33%, median = 10.1). A fraction of primary cells productively infected by HIV-1, in vitro, have high P-gp pump activity, demonstrating that infection does not inhibit P-gp function. In agreement with these data, HIV-susceptible cells expressing high levels of P-gp require higher levels of PI for complete inhibition of virus spread. We conclude that the PI concentrations achieved in plasma could be suboptimal for full inhibition of virus spread in high P-gp cells, indicating that they may represent a pharmacological sanctuary for HIV-1.