Study on the modeling of colony pattern selection of filamentous fungi

丝状真菌根据环境条件表现出多种菌落生长模式。在这项研究中，一个多层的菌丝菌落，营养水平，营养扩散和菌丝生长速度的三个主要参数构建。通过与真实的菌落生长的比较，探讨了菌丝菌落形态的选择规律，在没有营养扩散的情况下，模型菌落在任何营养水平下都表现出相当的自亲和性，菌落前沿的粗糙化程度都相当，殖民地生长都能维持。对于无限营养盐极限的情况也得到了同样的结果。然而，前粗糙度的增长指数被发现依赖于营养水平的多层模型。这些结果表明，菌丝在定殖空间内部的生产影响了菌落前沿的粗糙化，营养物质的扩散引起了生长模式的变化。特别是，随着增长率的提高， 关于我们 在固定营养水平和营养扩散系数下，TE降低，殖民地表现出反应限制生长，并形成密集的聚集模式。在此条件下，随着营养水平的降低，分枝形态通过反应限制过程发展，通过与真实的菌丝菌落形态的比较，发现模式选择规则存在于菌丝生长速率对环境营养水平的内在响应方式中。构巢曲霉的野生型和突变型菌株被分为两种类型，在任何营养和琼脂水平下保持均匀生长的菌株，以及在低营养水平下表现出分枝模式的菌株。通过测定不同营养水平下的殖民地扩展速率，这些形态类型可以与低营养水平下突变诱导的生长速率衰减相关联。此外，考虑到菌丝老化等生长抑制的影响，开始对A. nidulans和其他菌株。菌丝生长速率在生长过程中有逐渐或急剧衰减的现象，表明生长速率衰减的方式与环境营养水平有关。少

Filamentous fungi show variety of colony growth patterns depending upon the environmental conditions. In this study, a multi-layer mycelial colony that had three main parameters of nutrient level, nutrient diffusion and hyphal growth rate was constructed. By comparing the model growth with the real fungal colony growth, the selection rules of mycelial colony patterns were investigated.Without nutrient diffusion, the model colonies exhibited equivalent self-affinity in their roughening of colony fronts at any nutrient levels the colony growth can be maintained. The same result was also obtained for the cases of infinite nutrient limit case. However, the growth exponents of front roughness were found dependent upon the nutrient levels for the multi-layer models. These results showed that the hyphal production in the interior of the colonized space affected the roughening of colony fronts.The nutrient diffusion brought about the variation of growth patterns. Particularly, as the growth ra … More te was lowered at fixed nutrient levels and nutrient diffusion coefficient, the colony exhibited reaction-limited growth and formed densely aggregated patterns. Under this condition, as the nutrient level was lowered, the ramified morphology was found to develop through reaction-limited process.By comparing the model colony morphology with the real mycelial colonies, the pattern selection rule was found to exist in the inherent manner of response in the hyphal growth rate to the environmental nutrient levels. The wild and mutant strains of Aspergillus nidulans were grouped into two types; those maintained uniform growth at any nutrient and agar levels, and those exhibited ramified patterns at low nutrient levels. By measuring the colony expansion rates at various nutrient levels, these morphological types can be related with the mutation-induced decay of the growth rate at low nutrient levels.Further, to consider the effect of growth inhibition by the hyphal aging etc., long-term measurement of hyphal growth rate was commenced for A. nidulans and other strains. Gradual or steep decay of hyphal growth rate was found in the growth process, and it was suggested that the manner of growth rate reduction was dependent upon the environmental nutrient levels. Less