笔记|酿酒酵母Saccharomyces cerevisiae

酵母属于真菌。

但与我们更熟悉的蘑菇（蘑菇也是一种真菌）不同，它们不像蘑菇那样容易通过形态来表征，因为酵母非常小，需要通过显微镜来观察。

酿酒所涉及的酵母主要来自一个单一的家族，即糖酵母科Saccharomycetaceae，该家族包含数千种物种，但其中有一种特别的酿酒酵母Saccharomyces cerevisiae，对于葡萄酒生产至关重要。这种酵母可以有性繁殖和无性繁殖。当无性繁殖时，每个细胞都会“出芽buds”，产生类似斑点形状的子细胞，然后将复制的细胞核转移到子细胞中。

只要存在充足的碳水化合物来源（如糖），这类出芽酵母Budding yeasts 在环境中相当常见。与可以同时利用养分和阳光来产生能量的植物不同，真菌需要碳水化合物等养分来产生能量。

尽管如此，酵母仍然很丰富，而且由于其中许多酵母可以很容易地在实验室中生长，因此它们一直是科学研究的主题，不同酵母品种通常用于酿酒（以及烘烤面包和酿造啤酒）是这个星球上最重要的驯养物种domestic species 之一。

科学家们喜爱酿酒酵母，因为它是一种奇妙的遗传生物模型，且生长得很快，易于在实验室培养。酿酒酵母也是像葡萄和人类一样属于真核生物，出于所有这些原因，它是研究蛋白质如何相互作用以及基因如何参与这些相互作用的有用形式。

Yeasts are fungi. But unlike the more familiar mushrooms, they are not as easily characterized by their morphology as mushrooms are, largely because of their nondescript anatomy—which, because they are incredibly tiny, needs to be viewed through a microscope. The yeasts involved in winemaking come primarily from a single family, known cumbersomely as the Saccharomycetaceae. This family contains thousands of species, but one in particular, Saccharomyces cerevisiae, is essential to wine production. This yeast species reproduces both sexually and asexually. When reproducing asexually, each cell “buds” to create rather bloblike daughter cells, to which a duplicated nucleus is then transferred.

Budding yeasts are fairly common in the environment, wherever ample carbohydrate sources like sugar are present. Unlike plants that can use both nutrients and sunlight to produce energy, fungi need nutrients such as carbohydrates for this purpose. Yeasts are nonetheless abundant, and because many of them can easily be grown in the laboratory, they have been the subject of close scientific study—appropriately enough, because the yeast species that is generally used in winemaking (and in baking bread and brewing beer) is one of the most important domestic species on this planet. Scientists love Saccharomyces cerevisiae because it is a fantastic model genetic organism. It grows fast; it is easy to cultivate in the laboratory; and it is, of course, a eukaryote, as are grapes and humans. For all these reasons, it is a useful form with which to study how proteins interact, and how genes are involved in those interactions.