Ultralow freezer for gene expression analysis

批判性地理解认知的细胞基础，需要在同一动物的多个行为时期以细胞分辨率评估大脑广泛区域的神经活动模式。事实上，一种被称为荧光原位杂交（catFISH）的细胞间隔时间活性分析的灵敏技术允许通过可视化立即早期基因（egg）的转录来进行这种区分。参与信息处理的神经元立即转录在细胞核内可见几分钟的脑电图。随后，加工后的mRNA转运到细胞质中，在约30分钟时达到浓度峰值。由于mRNA可以在两个独立的细胞区室中被分解，因此有可能在同一动物的两个行为时期识别活跃的神经元。此外，在行为过程中转录eeg的细胞比例等于电生理记录产生的估计值。因此，像fMRI或PET一样，catFISH在同一受试者中提供大规模重复的神经元活动测量，但具有细胞分辨率，以检查介导认知的神经网络中的信号传导和可塑性。这个新的实验系统使我们能够检查信息处理和存储基础的神经网络中的信号和可塑性。事实上，使用这种方法，已经有可能可视化与海马体中的空间处理、后顶叶皮层的运动处理以及杏仁核和眼窝额叶皮层的进食行为相关的神经元。然而，在这一领域的进一步工作，迫切需要一个超低温冷冻机。尽量减少实验诱导的杂交产量变化所固有的实际限制使得组织的储存不可避免地要持续数天或数周。在此期间，在保持RNA完整性的温度下存储的可用性对生成数据的质量至关重要。

Understanding the cellular basis of cognition critically requires the assessment of patterns of neural activity over widespread regions of the brain during multiple epochs of behaviour in the same animal at cellular resolution. In fact, a sensitive technique, termed cellular compartment analysis of temporal activity by fluorescence in situ hybridization (catFISH) permits such discrimination by visualizing the transcription of immediate-early genes (IEGs). Neurons engaged in information processing immediately transcribe IEGs that are visible for several minutes within the nucleus. Subsequently, processed mRNA is trans-located to the cytoplasm, peaking in concentration at ~30 min. Because mRNA can be resolved in two independent cellular compartments, it is possible to identify active neurons during two behavioural epochs in the same animal. Moreover, the proportion of cells transcribing IEGs during behaviour equals estimates generated by electrophysiological recording. Thus, like fMRI or PET, catFISH provides large-scale repeated neuronal activity measurements in the same subject, but with the cellular resolution to examine signalling and plasticity in neural networks mediating cognition. This new experimental system allows us to examine signalling and plasticity in neural networks that underlie information processing and storage.  In fact, using this method it has been possible to visualize neurons associated with spatial processing in the hippocampus, movement processing in posterior parietal cortex, and feeding behaviour in the amygdala and orbitofrontal cortex.  Further work in this area, however, critically requires an ultra-low freezer.  The practical constraints inherent in  minimizing experimentally-induced variation in hybridization yield make the storage of tissue for days or weeks unavoidable. During these periods, the availability of storage at temperatures that maintain the integrity of RNA is critical to the quality of the data that is generated.