Nuclear import is a critical process for the cell: molecules are selectively permitted into the nuclear interior where the sheltered genome resides. The process of nuclear import can be biochemically studied in vitro using nuclei reconstituted from Xenopus egg extract components and X ...

The mechanosensitivity of voltage-gated (VG) channels is of biophysical, physiological, and pathophysiological interest. Xenopus oocytes offer a critical advantage for investigating the electrophysiology of recombinant VG channels subjected to membrane stretch, nam ...

The Xenopus laevis oocyte offers one of the most convenient expression systems for assaying the actions of candidate ligands on cloned ionotropic neurotransmitter receptors (also known as ligand-gated ion channels ). Their large size makes injection of complementary ribonucleic ...

The Xenopus oocyte is largely used as a cell expression system for studying both structure and function of transmitter receptors and ion channels. Messenger RNA extracted from the brain and injected into oocytes leads to the synthesis and membrane incorporation of many types of functional ...

Semi-intact cells are cells with plasma membranes that have been permeabilized by bacterial pore-forming toxins or surfactants. The addition of mitotic Xenopus egg extract to semi-intact cells can reconstitute a number of intracellular events that occur specifically at the onset of m ...

Microinjection of poliovirus RNA in Xenopus oocytes initiates a complete and authentic viral replication cycle that yields newly synthesized infectious virus. This system can be used to study the molecular mechanism of the different steps involved in virus replication. Interesti ...

The advantage of NMR over most other spectroscopic techniques lies in the ability to gain structural and dynamic information at atomic resolution. Every nucleus with spin gives rise to a signal that is characterized by a number of parameters (chemical shift, J-couplings, relaxation data, a ...

Polysaccharides are ubiquitous components of living tissues. They are storage compounds in both animals and plants, and form important structural elements in, for example, plant cell walls, insect exoskeletons, and animal connective tissues. In bacteria, they are important both as st ...

The biochemical/biomedical research community, the pharmaceutical industry, and, indeed, molecular biologists generally are faced with the increasing need for characterization of carbohydrate structures of recombinant glycoproteins and natural analogs. Cultured m ...

It is normal for a biological system to be in a dynamic state. The function of many biological systems depends on their flexibility, and here NMR can provide the experimental basis for investigating the mechanical function of such systems. The types of motions that are thought to occur in proteins, th ...

Plasma desorption mass spectrometry (PDMS) (1) is a method for the mol-wt determination of peptides and small proteins. The upper mass limit is, in optimal cases, approx 30 kDa, with a precision of about 0.1%. This precision far exceeds that of classical biochemical methods, such as SDS-gel electrop ...

The contribution of mass spectrometry to the solution of problems in protein biochemistry was limited until the development of methods of ionization that do not require derivatization or prior vaporization of the sample. Fast atom bombardment (FAB), introduced by Barber et al. in 1981 (1), is o ...

For more than 30 years, electron ionization mass spectrometry (EIMS) has played a key role in the structural determination of small biological compounds, largely because it has three advantages to offer: very high sensitivity compared to other structural methods, such as nuclear magnet ...

Mass spectrometry (MS) is a sensitive and powerful analytical technique, in which ionized sample molecules are separated according to their mass to charge ratios (m/z) by the application of electric and/or magnetic fields. If the ionization regime deposits sufficient excess energy, a pr ...

Matrix-assisted laser desorption/ionization (LDI) mass spectrometry (MS) is a very young method that has overcome the mass limitations for the mass spectrometry of biopolymers (1–4). Four years ago, a UV-absorbing matrix was used to extend the accessible mass range of UV-LDI of peptides, and a ...

Electron paramagnetic resonance (EPR), or electron spin resonance (ESR) spectroscopy, is a technique for studying paramagnetic materials, the molecules of which contain unpaired electrons. These comprise organic free radicals and transition metal ions. The biological signi ...

Xenopus oocytes, eggs, and embryos serve as an ideal model system to study several aspects of animal development (e.g., gametogenesis, fertilization, embryogenesis, and organogenesis). In particular, the Xenopus system has been extensively employed not only as a “living cell” system but ...

The Xenopus oocyte is a widely used model cell for studies of signal transduction mechanisms. Advances in microanalytical methods have made it feasible to perform rapid, localized collection of cytoplasm from individual Xenopus oocytes. Analytes contained in the cytoplasmic samp ...

Xenopus laevis has been used for many decades to study oocyte development and maturation. The Xenopus oocytes’ large size, relative abundance, and clearly defined progression of physical characteristics from oogonia to eggs make them ideal for studying oogenesis. In addition, the abil ...

Protein kinase A (PKA) activity is regulated by intracellular cyclic adenosine mono-phosphate. Conventional protein kinase assays after cell lysis are hence not suitable for analyzing PKA activities. In this chapter, we describe a new method for monitoring PKA activity in live cells. A tr ...