Sympathetic and adrenocorticoid influences on diet-induced thermogenesis and brown fat activity in the rat

Bilateral adrenalectomy markedly reduced body weight and energy gain and energetic efficiency of adult cafeteria-fed rats but enhanced the thermogenic response to food and stimulated brown fat activity. These changes were totally prevented by replacement of the animals with corticosterone (1 mg/rat/day). Unilateral denervation of the sympathetic nerves supplying the interscapular brown adipose tissue abolished the enhanced activity resulting from adrenalectomy and inhibited thermogenic activity in brown fat from cafeteria rats with intact adrenals, but had no effect in adrenalectomised animals treated with a high dose of corticosterone.     

Action Video Gaming and Cognitive Control: Playing First Person Shooter Games Is Associated with Improved Action Cascading but Not Inhibition

There is a constantly growing interest in developing efficient methods to enhance cognitive functioning and/or to ameliorate cognitive deficits. One particular line of research focuses on the possibly cognitive enhancing effects that action video game (AVG) playing may have on game players. Interestingly, AVGs, especially first person shooter games, require gamers to develop different action control strategies to rapidly react to fast moving visual and auditory stimuli, and to flexibly adapt their behaviour to the ever-changing context. This study investigated whether and to what extent experience with such videogames is associated with enhanced performance on cognitive control tasks that require similar abilities. Experienced action videogame-players (AVGPs) and individuals with little to no videogame experience (NVGPs) performed a stop-change paradigm that provides a relatively well-established diagnostic measure of action cascading and response inhibition. Replicating previous findings, AVGPs showed higher efficiency in response execution, but not improved response inhibition (i.e. inhibitory control), as compared to NVGPs. More importantly, compared to NVGPs, AVGPs showed enhanced action cascading processes when an interruption (stop) and a change towards an alternative response were required simultaneously, as well as when such a change had to occur after the completion of the stop process. Our findings suggest that playing AVGs is associated with enhanced action cascading and multi-component behaviour without affecting inhibitory control.     

Distribution of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) in natural habitats in California, USA

A total of 270 soil samples from 30 different habitats in 10 geographic regions of California were evaluated for the presence of rhabditid entomopathogenic nematodes. Nematodes were isolated from 26.3% of the samples. The recovered isolates were identified as Steinernema carpocapsae, S. feltiae, S. kraussei, S. longicaudum, S. oregonense, Heterorhabditis marelatus and H.bacteriophora. Among the steinernematids, S. kraussei and S. feltiae were the most commonly encountered species, generally occurring in acidic soils high in organic matter. Among the heterorhabditids, H. bacteriophora was isolated along the southern coast, whereas H. marelatus was recovered along the northern coast of California. Steinernematids were recovered from coniferous forests, oak woodlands and grasslands whereas heterorhabditids were isolated from coastal marshes.     

Symbiosis research, technology, and education: Proceedings of the 6th International Symbiosis Society Congress held in Madison Wisconsin, USA, August 2009

Symbiosis, the intimate association between two or more organisms, is a fundamental component of biological systems. Our ability to understand the processes involved in the establishment and function of Symbiosis has critical consequences for the health of humans and the world we live in. For example, a deeper understanding of how legumes and insects have harnessed the nitrogen-fixing capacity of microbes can pave the way toward novel strategies to decrease fertilizer use. Also, using insect models to elucidate links between diet, gut microbiota, and toxin sensitivity not only has implications for biological control strategies, but also will lend insights into similar links in the human gut ecosystem. These types of ideas were presented and discussed at the 6th International Symbiosis Society Congress held in Madison, Wisconsin August, 2009. Over 300 participants from 20 countries attended the 7-day event, which featured cutting-edge symbiosis research from many different perspectives and disciplines. The conference was organized thematically, with oral sessions focused on Evolution, Ecology, Metabolism, the Host-Microbe Interface, Threats to Earth Systems, Symbiosis Models and the Human Microbiome, Viruses and Organelles, and Symbiosis Education. World-renowned scientists, post-doctoral fellows, and students were given the opportunity to describe their most recent discoveries. Session chairs provided overviews of their programs which highlight how the comparative analysis of different systems reveal common trends underlying symbiotic associations, what tools and theory are being developed that may be applied more broadly in symbiosis research, how symbiosis research contributing solutions to global issues such as emerging antibiotic resistance, a need for alternative energy sources, the pursuit of sustainable agriculture and natural resources, and how symbiotic systems are ideal for educating people about the fascinating natural world around us. The following paragraphs provide an overview of the research and discussions that took place during the congress.     

Role of membrane potential and calcium in chemotactic sensing by bacteria

Changes in Escherichia coli membrane potential in response to a wide variety of chemotactic stimuli were measured using a permeant, lipophilic cation (tetraphenylphosphonium chloride) and a fluorescent dye (3-propyl-2-(5-(3-propyl-2(3H)-benzothiazolylidene)-1,3-pentadienyl)iodide). Some attractants and repellants caused permanent, monotonic depolarizations or hyperpolarizations. Not all chemoeffectors, however, produced potential changes, and the direction of change did not correlate with physiological responses to these compounds. Moreover, changes were observed in a number of chemotactic mutants. From these results, we conclude that perturbations in membrane potential effected by chemical stimuli are not related to chemotactic sensing. These findings, and the close correlation between cytoplasmic ionic conditions and membrane potential, led us to examine the role of calcium in chemotaxis. By growing cells in the presence of a calcium chelator, we were able to lower cellular calcium levels over tenfold, with no change in behavior. These results indicate that sensory transduction in these cells is not mediated by this cation.     

Gangliosides in blood serum of normal rats and Morris hepatoma 5123tc-bearing rats.

The effects of malignancy upon blood serum ganglioside patterns were investigated. Lipids extracted from the blood serum of Morris hepatoma 5123tc-bearing rats were characterized by severalfold increases in the content of hematosides, monosialogangliosides and disialogangliosides, as compared with lipids extracted from the serum of normal rats. However, the content of trisialogangliosides in lipids extracted from the serum of cancer-bearing rats substantially decreased. In general, the change in the profile of gangliosides in blood serum reflects, but is less pronounced, than that observed in the comparison of Morris hepatoma tissue to normal liver tissue.