Space-use behaviour of woodland caribou based on a cognitive movement model.

Movement patterns offer a rich source of information on animal behaviour and the ecological significance of landscape attributes. This is especially useful for species occupying remote landscapes where direct behavioural observations are limited. In this study, we fit a mechanistic model of animal cognition and movement to GPS positional data of woodland caribou (Rangifer tarandus caribou; Gmelin 1788) collected over a wide range of ecological conditions. The model explicitly tracks individual animal informational state over space and time, with resulting parameter estimates that have direct cognitive and ecological meaning. Three biotic landscape attributes were hypothesized to motivate caribou movement: forage abundance (dietary digestible biomass), wolf (Canis lupus; Linnaeus, 1758) density and moose (Alces alces; Linnaeus, 1758) habitat. Wolves are the main predator of caribou in this system and moose are their primary prey. Resulting parameter estimates clearly indicated that forage abundance is an important driver of caribou movement patterns, with predator and moose avoidance often having a strong effect, but not for all individuals. From the cognitive perspective, our results support the notion that caribou rely on limited sensory inputs from their surroundings, as well as on long-term spatial memory, to make informed movement decisions. Our study demonstrates how sensory, memory and motion capacities may interact with ecological fitness covariates to influence movement decisions by free-ranging animals.

Characterization of a nutrient feed precipitate from an E. coli fermentation process.

Metalloproteins require soluble metal ions such as zinc to properly fold into their native and active state to maintain stability and biological activity. When protein products are produced during microbial fermentations, metals are made available to the metalloproteins via nutrient supplements. During the production at the manufacturing-scale of a recombinant product that required zinc as a cofactor, an insoluble precipitate formed in the preparation tank after steam sterilization of the nutrient feed containing methionine, glycerophosphate, and zinc sulfate (MGZ). The precipitated nutrient feed was believed to be the cause for not enough zinc delivered to the production fermentor, leading to poor product assembly and stabilization. This article explores several analytical techniques such as capillary zone electrophoresis, inductively coupled plasma and phosphate molybdate assays to identify and quantify the composition of the precipitate. Our results show that the glycerophosphate component of the combined MGZ nutrient feed contains inorganic phosphate, which precipitates zinc from the feed media.