PubMed · 5496452
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O Kühnemund, Sickert. 1970. [An automatic buffer changer].. https://pubmed.ncbi.nlm.nih.gov/5496452/
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We have developed an automated, high-throughput, systematic cDNA display method called TOGA, an acronym for total gene expression analysis. TOGA utilizes 8-nt sequences, comprised of a 4-nt restriction endonuclease cleavage site and adjacent 4-nt parsing sequences, and their distances from the 3' ends of mRNA molecules to give each mRNA species in an organism a single identity. The parsing sequences are used as parts of primer-binding sites in 256 PCR-based assays performed robotically on tissue extracts to determine simultaneously the presence and relative concentration of nearly every mRNA in the extracts, regardless of whether the mRNA has been discovered previously. Visualization of the electrophoretically separated fluorescent assay products from different extracts displayed via a Netscape browser-based graphical user interface allows the status of each mRNA to be compared among samples and its identity to be matched with sequences of known mRNAs compiled in databases.
Due to the lack of suitable in-process sensors, on-line monitoring of fermentation processes is restricted almost exclusively to the measurement of physical parameters only indirectly related to key process variables, i.e., substrate, product, and biomass concentration. This obstacle can be overcome by near infrared (NIR) spectroscopy, which allows not only real-time process monitoring, but also automated process control, provided that NIR-generated information is fed to a suitable computerized bioreactor control system. Once the relevant calibrations have been obtained, substrate, biomass and product concentration can be evaluated on-line and used by the bioreactor control system to manage the fermentation. In this work, an NIR-based control system allowed the full automation of a small-scale pilot plant for lactic acid production and provided an excellent tool for process optimization. The growth-inhibiting effect of lactic acid present in the culture broth is enhanced when the growth-limiting substrate, glucose, is also present at relatively high concentrations. Both combined factors can result in a severe reduction of the performance of the lactate production process. A dedicated software enabling on-line NIR data acquisition and reduction, and automated process management through feed addition, culture removal and/or product recovery by microfiltration was developed in order to allow the implementation of continuous fermentation processes with recycling of culture medium and cell recycling. Both operation modes were tested at different dilution rates and the respective cultivation parameters observed were compared with those obtained in a conventional continuous fermentation. Steady states were obtained in both modes with high performance on lactate production. The highest lactate volumetric productivity, 138 g L(-1) h(-1), was obtained in continuous fermentation with cell recycling.
The separation of seven pesticides by micellar electrokinetic capillary chromatography in spiked water samples is described, allowing the analysis of pesticides mixtures down to a concentration of 50 microg l(-1) in less than 13 min. Calibration, pre-concentration, elution and injection into the sample vial was carried out automatically by a continuous flow system (CFS) coupled to a capillary electrophoresis system via a programmable arm. The whole system was electronically coupled by a micro-processor and completely controlled by a computer. A C18 solid-phase mini-column was used for the pre-concentration, allowing a 12-fold enrichment (as an average value) of the pesticides from fortified water samples. Under the optimal extraction conditions, recoveries between 90 and 114% for most of the pesticides were obtained.