Crandall M, Lawrence L J
J Bacteriol. 1980 Apr;142(1):276-84. doi: 10.1128/jb.142.1.276-284.1980.
The sexually agglutinative yeast Hansenula wingei lives in association with bark beetles that inhabit coniferous trees. This yeast was induced to sporulate by malt extract, which contains a high percentage of maltose (50%) and a low percentage of nitrogen (0.5%). A solution of 1.5% maltose without any growth factors also induced ascosporogenesis in H. wingei. Thus, only a carbon source is required for sporulation as in Saccharomyces. However, potassium acetate did not induce sporulation in H. wingei as it does in S. cerevisiae. Instead, disaccharides (such as maltose, sucrose, or cellobiose) promote sporulation better than either monosaccharides (such as dextrose, fructose, or mannose) or respiratory substrates (such as ethanol or glycerol). The specificity of disaccharides in promoting sporulation in H. wingei may be considered an adaptation since these disaccharides are present in the natural environment of this yeast. In addition, the specificity of disaccharides may be related to the induction of the disaccharidase because cells precultured on dextrose sporulate well on maltose, but cells precultured on maltose sporulate poorly on maltose. When (NH(4))(2)SO(4) was added at a low concentration (3 mM) to synthetic sporulation medium (1.5% maltose solution), sporulation was abolished, whereas other salts and nitrogen sources inhibited to a lesser extent and vitamins and trace elements had no effect. Oxygen was required for sporulation, as expected for an obligate aerobe. Maximal sporulation was achieved in 2% malt extract broth at high cell density (10(9) cells per ml), pH 5, and 25 degrees C. By using these optimal physiological conditions and hybrid strains selected from an extensive genetic breeding program, about 30% asci (10% tetrads) were obtained routinely. Thus, the genetics of cell recognition in this yeast can now be studied.
性凝集酵母汉逊威格酵母与栖息在针叶树上的树皮甲虫共生。这种酵母可被麦芽提取物诱导形成孢子，麦芽提取物含有高比例的麦芽糖（50%）和低比例的氮（0.5%）。不含任何生长因子的1.5%麦芽糖溶液也能诱导汉逊威格酵母形成子囊孢子。因此，与酿酒酵母一样，孢子形成仅需一种碳源。然而，醋酸钾不像在酿酒酵母中那样能诱导汉逊威格酵母形成孢子。相反，二糖（如麦芽糖、蔗糖或纤维二糖）比单糖（如葡萄糖、果糖或甘露糖）或呼吸底物（如乙醇或甘油）更能促进孢子形成。二糖在促进汉逊威格酵母孢子形成方面的特异性可被视为一种适应性，因为这些二糖存在于这种酵母的自然环境中。此外，二糖的特异性可能与二糖酶的诱导有关，因为在葡萄糖上预培养的细胞在麦芽糖上能很好地形成孢子，但在麦芽糖上预培养的细胞在麦芽糖上形成孢子的情况较差。当在合成孢子形成培养基（1.5%麦芽糖溶液）中添加低浓度（3 mM）的硫酸铵时，孢子形成被抑制，而其他盐类和氮源的抑制作用较小，维生素和微量元素则没有影响。正如专性需氧菌所预期的那样，孢子形成需要氧气。在2%麦芽提取物肉汤中，细胞密度高（每毫升10⁹个细胞）、pH值为5、温度为25℃时可实现最大孢子形成。通过使用这些最佳生理条件以及从广泛的遗传育种计划中选择的杂交菌株，通常可获得约30%的子囊（10%的四分体）。因此，现在可以研究这种酵母中细胞识别的遗传学。
