The release of GLP-1 from gut L cells is inhibited by low extracellular pH.

Objective: The intestinal luminal pH profile varies from stomach to rectum and becomes disrupted in diseases. However, little is known about the pH dependence of incretin hormone secretion, with most in vitro studies having failed to consider this modulatory factor or having used nonphysiological buffer systems. Here, we report the extracellular pH (pHe) dependence of glucagon-like peptide-1 (GLP-1) exocytosis from L cells.

Ab Initio Calculation of UV-vis Absorption of Parent Mg, Fe, Co, Ni, Cu, and Zn Metalloporphyrins.

Relativistic restricted active space (RAS) second-order multireference perturbation theory (MRPT2) methods, incorporating spin-orbit (SO) coupling perturbatively via state interaction (SO-MRPT2/RASSCF), were used to reproduce the absorption spectra of parent metalloporphyrins containing the Mg, Zn, Co, Ni, Cu, or FeCl ions in the 12,500-40,000 cm region. Particular attention was paid to the interaction between the porphyrin ring and the metal 3 electrons in states of different multiplicities (we used metal 3 and double -shell or 3' orbitals). For this class of compounds, the -electron valence state perturbation theory (NEVPT2) method is superior to the complete active space perturbation theory (CASPT2) and successfully reproduces the energies of all four characteristic transitions (, , , and ) of closed-shell metalloporphyrins.

Phenotypic screen of sixty-eight colorectal cancer cell lines identifies CEACAM6 and CEACAM5 as markers of acid resistance.

Elevated cancer metabolism releases lactic acid and CO into the under-perfused tumor microenvironment, resulting in extracellular acidosis. The surviving cancer cells must adapt to this selection pressure; thus, targeting tumor acidosis is a rational therapeutic strategy to manage tumor growth. However, none of the major approved treatments are based explicitly on disrupting acid handling, signaling, or adaptations, possibly because the distinction between acid-sensitive and acid-resistant phenotypes is not clear.

Electronic Structure of Metalloporphenes, Antiaromatic Analogues of Graphene.

Zinc porphene is a two-dimensional material made of fully fused zinc porphyrins in a tetragonal lattice. It has a fully conjugated π-system, making it similar to graphene. Zinc porphene has recently been synthesized, and a combination of rough conductivity measurements and infrared and Raman spectroscopies all suggested that it is a semiconductor (Magnera, T.