A Flame-Free Method for Sterilizing C. elegans Picks, Spatulas, and Scalpels.

Caenorhabtidis elegans (C. elegans) is an optimal model organism for research and education at primarily undergraduate institutions. Undergraduates can quickly learn the sterile technique required to maintain C. elegans cultures. Sterilization of platinum picks used to transfer worms from one plate to another is traditionally done by holding the pick in a flame from a Bunsen burner or ethanol lantern. However, Bunsen burners require a gas source, and both pieces of equipment pose the risk of accidental fire associated with an open flame. Demonstrated here is a technique for sterilizing worm picks, spatulas, and scalpels using an infrared bacteriological loop micro-incinerator. This equipment requires only an electrical outlet and minimizes potential fire hazards. By lowering risk and gas requirements, this technique is well suited for research and teaching in an undergraduate setting.

Behavioral Differences between Male and Hermaphrodite C. elegans.

C. elegans are microscopic nematodes used extensively as a model organism due to their simplicity, allowing researchers to study basic molecular processes in biology. Most C. elegans are hermaphrodites, possessing two X chromosomes and the ability to reproduce asexually, but approximately 0.1% are males, arising due to a spontaneous loss of an X chromosome. In order to evaluate the behavioral sex differences in C. elegans, we expanded upon existing literature and compared spontaneous movement, sensitivity to mechanosensation, and sensitivity to chemosensation between males and hermaphrodites. In our paradigms, we found that males and hermaphrodites exhibit similar spontaneous movement as well as similar slow and sustained behaviors such as chemotaxis, but differ in quick-response to mechanical and chemosensory stimuli.

The glutamate transporter, GLAST, participates in a macromolecular complex that supports glutamate metabolism.

GLAST is the predominant glutamate transporter in the cerebellum and contributes substantially to glutamate transport in forebrain. This astroglial glutamate transporter quickly binds and clears synaptically released glutamate and is principally responsible for ensuring that synaptic glutamate concentrations remain low. This process is associated with a significant energetic cost. Compartmentalization of GLAST with mitochondria and proteins involved in energy metabolism could provide energetic support for glutamate transport. Therefore, we performed immunoprecipitation and co-localization experiments to determine if GLAST might co-compartmentalize with proteins involved in energy metabolism. GLAST was immunoprecipitated from rat cerebellum and subunits of the Na(+)/K(+) ATPase, glycolytic enzymes, and mitochondrial proteins were detected. GLAST co-localized with mitochondria in cerebellar tissue. GLAST also co-localized with mitochondria in fine processes of astrocytes in organotypic hippocampal slice cultures. From these data, we hypothesized that mitochondria participate in a macromolecular complex with GLAST to support oxidative metabolism of transported glutamate. To determine the functional metabolic role of this complex, we measured CO(2) production from radiolabeled glutamate in cultured astrocytes and compared it to overall glutamate uptake. Within 15 min, 9% of transported glutamate was converted to CO(2). This CO(2) production was blocked by inhibitors of glutamate transport and glutamate dehydrogenase, but not by an inhibitor of glutamine synthetase. Our data support a model in which GLAST exists in a macromolecular complex that allows transported glutamate to be metabolized in mitochondria to support energy production.