Xenopus laevis oocytes infected with multi-drug-resistant bacteria: implications for electrical recordings

The Xenopus laevis oocyte has been the workhorse for the investigation of ion transport proteins. These large cells have spawned a multitude of novel techniques that are unfathomable in mammalian cells, yet the fickleness of the oocyte has driven many researchers to use other membrane protein expression systems. Here, we show that some colonies of Xenopus laevis are infected with three multi-drug-resistant bacteria: Pseudomonas fluorescens, Pseudomonas putida, and Stenotrophomonas maltophilia. Oocytes extracted from infected frogs quickly (3-4 d) develop multiple black foci on the animal pole, similar to microinjection scars, which render the extracted eggs useless for electrical recordings. Although multi-drug resistant, the bacteria were susceptible to amikacin and ciprofloxacin in growth assays. Supplementing the oocyte storage media with these two antibiotics prevented the appearance of the black foci and afforded oocytes suitable for whole-cell recordings. Given that P. fluorescens associated with X. laevis has become rapidly drug resistant, it is imperative that researchers store the extracted oocytes in the antibiotic cocktail and not treat the animals harboring the multi-drug-resistant bacteria

Finding the striatum in sheep: use of a multi-modal guided approach for convection enhanced delivery

Our goal is delivery of a long-term treatment for Huntington\u27s disease. We administer intracerebrally in sheep adeno-associated virus (AAV) to establish optimal safety, spread and neuronal uptake of AAV based therapeutics. Sheep have large gyrencephalic brains and offer the opportunity to study a transgenic Huntington\u27s disease model. However, lack of a relevant brain stereotactic atlas and the difficulty of skull fixation make conventional stereotaxy unreliable. We describe a multi-modal image-guidance technique to achieve accurate placement of therapeutics into the sheep striatum