However, a review of the scientific literature suggests that this mechanism of action is unlikely to be true. For while plant cell walls are made predominantly of cellulose, yeast cell walls are not (yeast are classified as fungi). For example, in the article, "Synthesis of the yeast cell wall and its regulation" in the "Annual Review of Biochemistry", there is mention of many other complex carbohydrates found in yeast cell walls, but there is no mention of cellulose nor is cellulose mentioned as a cell wall component in "candida albicans", the yeast strain most frequently associated with human fungal infections. Indeed, scientists have even modified yeast cells so they can make their own cellulases. This allows the modified yeast to ferment widely available plant material, which is made mostly of cellulose, and turn plant cellulose into alcohol for biofuels (cellulosic ethanol). One scientific article even called yeast an "ideal host strain" for producing cellulases. This is consistent with cellulase not being toxic to yeast and no mention was made of any toxic effect of cellulases on the modified yeast.