Surprising Antibacterial Activity and Selectivity of Hydrophilic Polyphosphoniums Featuring Sugar and Hydroxy Substituents.

There is currently an urgent need for the development of new antibacterial agents to combat the spread of antibiotic-resistant bacteria. We explored the synthesis and antibacterial activities of novel, sugar-functionalized phosphonium polymers. While these compounds exhibited antibacterial activity, we unexpectedly found that the control polymer poly(tris(hydroxypropyl)vinylbenzylphosphonium chloride) showed very high activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus and very low haemolytic activity against red blood cells.

Secondary Bacterial Pneumonia by Staphylococcus aureus Following Influenza A Infection Is SaeR/S Dependent.

Staphylococcus aureus is a predominant cause of fatal pneumonia following influenza A virus (IAV) infection. Herein we investigate the influence of antecedent IAV infection on S. aureus virulence gene expression.

Effect of Counterions on the Self-Assembly of Polystyrene-Polyphosphonium Block Copolymers.

The ability to manipulate block copolymers on the nanoscale has led to many scientific and technological advances. These include nanoscale ordered bulk and thin films and also solution phase components; these are promising materials for making smaller ordered electronics, selective membranes, and also biomedical applications. The ability to manipulate block copolymer material architectures on such small scales has risen from thorough investigations into the properties that affect the architectures.

Phosphonium-Functionalized Polymer Micelles with Intrinsic Antibacterial Activity.

New approaches to treat bacterial infections are badly needed to address the increasing problem of antibiotic resistance. This study explores phosphonium-functionalized block copolymer micelles as intrinsically antibacterial polymer assemblies. Phosphonium cations with varying alkyl lengths were conjugated to the terminus of a poly(ethylene oxide)-polycaprolactone block copolymer, and the phosphonium-functionalized block copolymers were self-assembled to form micelles in aqueous solution.

Effects of fiber type on force depression after active shortening in skeletal muscle.

The aim of this study was to investigate force depression in Type I and Type II muscle fibers. Experiments were performed using skinned fibers from rabbit soleus and psoas muscles. Force depression was quantified after active fiber shortening from an average sarcomere length (SL) of 3.

Does residual force enhancement increase with increasing stretch magnitudes?

It is generally accepted that force enhancement in skeletal muscles increases with increasing stretch magnitudes. However, this property has not been tested across supra-physiological stretch magnitudes and different muscle lengths, thus it is not known whether this is a generic property of skeletal muscle, or merely a property that holds for small stretch magnitudes within the physiological range. Six cat soleus muscles were actively stretched with magnitudes varying from 3 to 24 mm at three different parts of the force-length relationship to test the hypothesis that force enhancement increases with increasing stretch magnitude, independent of muscle length.

Benzodiazepine receptors and cerebrospinal fluid formation.

There is autoradiographic evidence that peripheral-type benzodiazepine ligands bind with high affinity to the membranes of choroid plexus tissue. In this study, the binding of a 4'-chloro analog of diazepam (Ro 5-4864) to rabbit choroid plexus and cerebral cortex was accomplished utilizing an in vitro radioactive assay method. A kinetic analysis of this binding revealed a relatively high affinity of this ligand (KD) for peripheral binding sites in plexus tissue (KD = 16.

Choroid plexus Na+/K+-activated adenosine triphosphatase and cerebrospinal fluid formation.

The quantitative relationship between intraventricular fluid formation and choroid plexus Na+/K+-activated (transport) adenosine triphosphatase (ATPase) was studied in rabbit and dog by perfusing the ventricular system with a solution containing ouabain (10(-8) to 10(-3) M). The effect of ouabain in the same range of concentrations on ATPase activity was also measured by the release of inorganic orthophosphate from in vitro choroid plexus tissue. Normally, about 20 to 25% of ATPase activity in lateral ventricle plexus is Na+/K+-activated, and this component is almost completely inhibited by ouabain in a concentration of 10(-4) M.

In vitro evaluation of CSF shunt function by radionuclides.

An in vitro study of clearance of a radiolabeled marker was conducted on nine commonly used shunting devices. Clearance of 0.5 ml of 113mIn-diethylenetriamine-pentaacetic acid (DTPA) injected into the chamber, by water infused through the system at constant rate (0.

Position effect influencing alcohol dehydrogenase activity in Drosophila melanogaster.

A small decrease in alcohol dehydrogenase activity was found in translocation stocks of Drosophila melanogaster in which a section of the heterochromatic Y-chromosome is inserted proximal to Adh. This small position effect is consistent with our growing knowledge of the control and transcription of the Adh locus.