The repression of siderophore synthesis by Mt. St. Helens' ash and silicate rock standards

Summary Mt. St. Helens' ash or U.S. Geological Survey silicate rock standards would replace FeCl₃ as the limiting nutrient and repress the synthesis of rhodotorulic acid inRhodotorulia pilimanae cultures.     

Inhibitory action of cholecystokinin-pancreozymin on gastric pepsin secretion

Zusammenfassung Der Einfluss von Cholecystokinin-Pankrcozymin auf die Sekretion von Pepsin wurde in Hunden mit Heidenhain-Tasche untersucht. Während submaximaler Pepsinstimulation mit Mecholyl verminderte i.v. Injektion von Cholecystokinin-Pankreozymin die Pepsin-Sekretion im Magen signifikant. Es wird vermutet, dass CCK-PZ Enterogastrone sein könnte.     

Compartmentalized dendritic plasticity and input feature storage in neurons

Although information storage in the central nervous system is thought to be primarily mediated by various forms of synaptic plasticity, other mechanisms, such as modifications in membrane excitability, are available. Local dendritic spikes are nonlinear voltage events that are initiated within dendritic branches by spatially clustered and temporally synchronous synaptic input. That local spikes selectively respond only to appropriately correlated input allows them to function as input feature detectors and potentially as powerful information storage mechanisms. However, it is currently unknown whether any effective form of local dendritic spike plasticity exists. Here we show that the coupling between local dendritic spikes and the soma of rat hippocampal CA1 pyramidal neurons can be modified in a branch-specific manner through an N-methyl-d-aspartate receptor (NMDAR)-dependent regulation of dendritic Kv4.2 potassium channels. These data suggest that compartmentalized changes in branch excitability could store multiple complex features of synaptic input, such as their spatio-temporal correlation. We propose that this 'branch strength potentiation' represents a previously unknown form of information storage that is distinct from that produced by changes in synaptic efficacy both at the mechanistic level and in the type of information stored.     

Is secretin enterogastrone?

Résumé On a prétendu que la sécrétine est 1'« entérogastrone» libérée quand le pH du duodénum est 3 ou moins. Nous croyons que ce n'est pas possible parce que la sécrétine fait augmenter la pepsine tandis que si le pH d'une poche de duodénum est plus bas que 3, la sécrétion de l'acide et de la pepsine gastriques diminuent.     

The siderophore mediated release of iron and magnesium from Mt St. Helens' ash and silicate rock standards

Summary Substantial amounts of iron and magnesium were observed to be released from ash from Mt St. Helens' and US Geological Survey Silicate Rock Standards by the siderophore rhodotorulic acid.This project was supported by the Robert A. Welch Foundation (Y-773) and the Lamar Research Council. We are grateful to S. Arnow, W. Matthews III, V. Pullen and M. Akers for their interest and assistance in obtaining Mt St. Helens' ash samples.