A micro-volume adaptation of a stopped-flow system; use with μg quantities of muscle proteins.

Stopped-flow spectroscopy is a powerful method for measuring very fast biological and chemical reactions. The technique however is often limited by the volumes of reactants needed to load the system. Here we present a simple adaptation of commercial stopped-flow system that reduces the volume needed by a factor of 4 to ≈120 μl.

Anion-Initiated Trifluoromethylation by TMSCF: Deconvolution of the Siliconate-Carbanion Dichotomy by Stopped-Flow NMR/IR.

The mechanism of CF transfer from RSiCF (R = Me, Et, iPr) to ketones and aldehydes, initiated by MX (<0.004 to 10 mol %), has been investigated by analysis of kinetics (variable-ratio stopped-flow NMR and IR), C/H KIEs, LFER, addition of ligands (18-c-6, crypt-222), and density functional theory calculations. The kinetics, reaction orders, and selectivity vary substantially with reagent (RSiCF) and initiator (MX).

Base-Catalyzed Aryl-B(OH) Protodeboronation Revisited: From Concerted Proton Transfer to Liberation of a Transient Aryl Anion.

Pioneering studies by Kuivila, published more than 50 years ago, suggested ipso protonation of the boronate as the mechanism for base-catalyzed protodeboronation of arylboronic acids. However, the study was limited to UV spectrophotometric analysis under acidic conditions, and the aqueous association constants (K) were estimated. By means of NMR, stopped-flow IR, and quenched-flow techniques, the kinetics of base-catalyzed protodeboronation of 30 different arylboronic acids has now been determined at pH > 13 in aqueous dioxane at 70 °C.

Euthanasia by CO₂ inhalation affects potassium levels in mice.

We and others frequently have noted serum potassium levels of 8.0 +/- 0.85 mEq/L or greater in laboratory mice; this concentration has even been published as the upper limit of a 'normal' reference range.

Synergid cell death in Arabidopsis is triggered following direct interaction with the pollen tube.

During angiosperm reproduction, one of the two synergid cells within the female gametophyte undergoes cell death prior to fertilization. The pollen tube enters the female gametophyte by growing into the synergid cell that undergoes cell death and releases its two sperm cells within the degenerating synergid cytoplasm to effect double fertilization. In Arabidopsis (Arabidopsis thaliana) and many other species, synergid cell death is dependent upon pollination.

SCARFACE encodes an ARF-GAP that is required for normal auxin efflux and vein patterning in Arabidopsis.

To identify molecular mechanisms controlling vein patterns, we analyzed scarface (sfc) mutants. sfc cotyledon and leaf veins are largely fragmented, unlike the interconnected networks in wild-type plants. SFC encodes an ADP ribosylation factor GTPase activating protein (ARF-GAP), a class with well-established roles in vesicle trafficking regulation.