PubMed · 4107174
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B E Murphy. 1971. In vitro tests of thyroid function.. https://doi.org/10.1016/s0001-2998(71)80004-1
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Fusel alcohols are natural products of amino acid catabolism in the yeast Saccharomyces cerevisiae that cause morphological changes similar to those seen during pseudohyphal growth. We have discovered that certain of these alcohols, including butanol and isoamyl alcohol, bring about a rapid inhibition of translation at the initiation step. This inhibition is strain specific and is not explained by previously described translational control pathways. Using genetic mapping, we have identified a proline to serine allelic variation at amino acid 180 of the GCD1 gene product as the genetic locus that allows translational regulation upon butanol addition. Gcd1p forms part of the eIF2B guanine nucleotide complex that is responsible for recycling eIF2-GDP to eIF2-GTP. This represents one of the key limiting steps of translation initiation and we provide evidence that fusel alcohols target eIF2B in order to bring about translational regulation.
The development of new or improved analytical methods requires new enzymes. Screening techniques utilizing enrichment cultures and rapid assay methods supported by automated or miniaturized methods are useful tools to detect new enzyme producers. Notably, oxidoreductases are well suited for analytical purposes. The NAD(P)- and oxygen-independent quinoprotein dehydrogenases with a covalently bound redox cofactor can be used advantageously for the development of biosensors. Examples are given of selective enrichment methods used in screening for useful enzyme-producing microorganisms. Enrichment under chemostatic conditions proved to be successful because enzymes with a remarkably high affinity against the analyte could be obtained. This is demonstrated by the screening of a trimethylamine-converting enzyme. The frequently observed high selectivity of these enzymes against the substrate is demonstrated in a few examples. In exploitation of these new oxidoreductases, new analytical methods were developed which are useful for the detection and during monitoring of phenylketonuria (PKU) or maple syrup urine disease (MSUD).
In this review a universal thermistor-based biosensor system is described with examples from clinical chemistry, bioprocess monitoring and environmental control. The technique is based on the measurement of the small temperature changes associated with enzymatic reactions occurring in a microreactor with immobilized enzyme. The system has good operational stability and a sensitivity that permits measurements down to 1 microM concentrations. Current developments include devices constructed by micromachining for multisensing purposes and miniaturised instrumentation intended for use in portable monitoring. With use of special supports for enzyme immobilisation even untreated whole blood samples can be applied. Another current line of investigation involves hybrid biosensors, such as combinations of electrochemistry and calorimetry into bioelectrocalorimetric devices with interesting new properties.