Neurotransmitters and Neuropeptides: New Players in the Control of Islet of Langerhans' Cell Mass and Function.

Islets of Langerhans control whole body glucose homeostasis, as they respond, releasing hormones, to changes in nutrient concentrations in the blood stream. The regulation of hormone secretion has been the focus of attention for a long time because it is related to many metabolic disorders, including diabetes mellitus. Endocrine cells of the islet use a sophisticate system of endocrine, paracrine and autocrine signals to synchronize their activities.

Observing Xenopus laevis oocyte plasma membrane by Atomic Force Microscopy.

This paper describes the use of Atomic Force Microscopy (AFM) to investigate the plasma membrane of Xenopus laevis oocyte. Different protocols of sample preparation to perform an AFM investigation of both external and intracellular sides of the oocyte plasma membrane are presented and discussed. Reproducible AFM images allowed visualization and dimensional characterization of protein complexes differently arranged on both sides of the oocyte plasma membrane.

The SLC6/NSS family members KAAT1 and CAATCH1 have weak chloride dependence.

KAAT1 and CAATCH1 are amino acid transporters cloned from the intestine of the lepidoptera Manduca sexta. They are members of the SLC6/NSS family, which groups membrane proteins that use Na(+), K(+), and Cl⁻ gradients for the coupled transport of amines and amino acids. The report of the atomic-resolution x-ray crystal structure of the eubacterium Aquifex aeolicus leucine transporter (AaLeuT) has contributed significantly to understanding of the structure-function relationship in NSS proteins.

Atomic force microscopy imaging of Xenopus laevis oocyte plasma membrane purified by ultracentrifugation.

Atomic force microscopy (AFM) was used to investigate the native plasma membrane of Xenopus laevis (X. laevis) oocyte purified by means of ultracentrifugation on sucrose gradient and subsequently adsorbed on mica leaves through a physisorption process. Reproducible AFM topography images were collected, analyzed, and compared.