Metabolic probes for imaging endosymbiotic bacteria within toxic dinoflagellates

Fluorescence microscopy offers an important tool for the study of complex biological phenomena such as symbiosis. Here we identify a strategy that adapts the unique differences between the secondary metabolism in host and guest symbiotic species to selectively image endosymbiotic organisms. The method is demonstrated by application to the complex symbiotic relationships in toxic marine dinoflagellates.     

A Differential Harnack Inequality for the Newell-Whitehead-Segel Equation

This paper will develop a Li-Yau-Hamilton type differential Harnack estimate for positive solutions to the Newell-Whitehead-Segel equation on R^n.We then use our LYH-differential Harnack inequality to prove several properties about positive solutions to the equation,including deriving a classical Harnack inequality and characterizing standing solutions and traveling wave solutions.     

A three-component photoreversible tag for thiols

[structure: see text] A one-pot coupling of a 1,3-diketone, an aldehyde, and an alkanethiol has been developed to produce a protected sulfide. Through use of an o-nitrophenylbenzaldehyde, this method provides a one-step route to a photochemically reversible thiol-protecting group. The kinetics of photolysis were established using (1)H NMR analysis, which allows for the rate to be based on the entire reaction scheme.     

One-pot chemo-enzymatic synthesis of reporter-modified proteins

To meet recent advancements in the covalent reporter labeling of proteins, we propose a flexible synthesis for reporter analogs. Here we demonstrate a one-pot chemo-enzymatic synthesis of reporter-labeled proteins that allows the covalent tethering of any amine-terminal fluorescent or affinity label to a carrier protein or fusion construct. This two-reaction sequence consists of activated panthothenate coupling, biosynthetic conversion to the coenzyme A (CoA) analog, and enzymatic carrier protein modification via phosphopantetheinyltransferase (PPTase). We also probe substrate specificity for CoAA, the first enzyme in the pathway. With this approach CoA analogs may be rapidly prepared, thus permitting the regiospecific attachment of reporter moieties from a variety of molecular species.     

Sorption of neptunium on clays

Batch sorption experiments with²³⁷Np using kaolinite and molasse clays were carried out under oxic conditions. The sorption kinetics and the effects of particle size of clay samples, concentration of neptunium in the solutions and the pH below and above the point of zero charge of the clays on the sorption coefficients were studied. The sorption coefficients of neptunium, on kaolinite were between 23 and 1100 ml/g at pH 1.5 and 7.6, respectively, whereas, sorption on the molasse clay was not affected significantly by pH (R_d600 ml/g).     

Modular synthesis of pantetheine and phosphopantetheine

[structure: see text] D-Pantetheine and D-phosphopantetheine, precursors to coenzyme A, have been synthesized though a linear sequence from three modules (M1-M3) in 9 and 10 steps, respectively. These routes provide access to analogues of coenzyme A containing modified cystamines, beta-alanines, and pantoic acid residues. All three modules were joined using conventional methods of peptide synthesis. The chiral component, M3, was derived from D-pantolactone.