BIOCHEMISTRY & CYTOLOGY OF WALL SYNTHESIS IN FUNGI

本研究的主要目的是了解壳聚糖（几丁质） 合成酶微泡）在体内的作用以及细胞 壁几丁质微纤维由生长的真菌合成。 我们以前的 研究已经证明， 真菌以壳聚糖体的形式存在。 这些微泡是 据信会移动到细胞表面， 被激活（可能是通过蛋白水解）， 甲壳素的机制，其精确的网站和细节仍然未知。 一 研究的重点是壳聚糖体是否与 质膜，从而几丁质合成酶成为一个组成部分， 这个膜。 我们计划追踪细胞内的起源和命运 探讨壳聚糖体与质膜的相互作用 囊泡在体外。 因此，我们将奋进开发关键的 分离最高纯度的质膜样品的程序 真菌的生长的、有壁细胞。 将比较两种真菌。 此外 鲁氏毛霉，我们的主要测试生物，我们也将检查脉孢菌 crassa，主要是因为它被证明适合质膜 research. 几丁质合成酶的细胞定位将通过 无细胞提取物的分级和通过金或 铁蛋白标记的抗几丁质合成酶抗体。 通过这些研究 我们希望能揭示真菌几丁质纤维的组装机制， 墙 几丁质不是毛霉中唯一由几丁质合成酶合成的聚合物 rouxii;我们已经发现，这种真菌使壳聚糖通过协调 糖基转移和脱乙酰化（通过几丁质合成酶和几丁质 脱乙酰酶） 这项研究的另一个主要目标是进一步 了解协调行动的细节， 壁聚合物。 这项研究是一项长期计划的一部分， 毛霉形态发生的生化基础。

The main purpose of this study is to understand how chitosomes (chitin synthetase microvesicles) operate in vivo and the mechanism by which cell wall chitin microfibrils are synthesized by a growing fungus. Our previous studies have demonstrated that a major part of the chitin synthetase in fungi is present in the form of chitosomes. These microvesicles are believed to move to the cell surface where their chitin synthetase zymogen becomes activated (probably by proteolysis) and where they synthesize chitin by a mechanism whose precise site and details are still unknown. A major point to investigate is whether or not chitosomes fuse with the plasma membrane and thereby chitin synthetase becomes an integral part of this membrane. We plan to trace the intracellular origin and fate of chitosomes and to explore the interaction of chitosomes and plasma membrane vesicles in vitro. For this reason, we will endeavor to develop critical procedures to isolate plasma membrane samples of highest purity from growing, walled cells of fungi. Two fungi will be compared. In addition to Mucor rouxii, our main test organism, we will also examine Neurospora crassa, mainly because of its proven suitability for plasma membrane research. The cellular localization of chitin synthetase will be traced by fractionation of cell-free extracts and by means of gold-or ferritin-labelled anti-chitin synthetase antibodies. Through these studies we hope to unravel the mechanism of chitin fibril assembly in fungal walls. Chitin is not the only polymer made by chitin synthetase in Mucor rouxii; we have found that this fungus makes chitosan through a coordinated glycosyl transfer and deacetylation (via chitin synthetase and chitin deacetylase.) Another major goal of this study will be to further understand details of the coordinated action that produces this important wall polymer. This study is part of a long-standing program to elucidate the biochemical bases of morphogenesis of Mucor.