Wesel Jordan, Ingram-Smith Cheryl
Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA.
Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, SC 29634, USA.
Life (Basel). 2023 Jul 8;13(7):1529. doi: 10.3390/life13071529.
is a parasitic protozoan that causes diarrheal disease in approximately 100 million people worldwide every year. has two forms, the growing trophozoite and the infectious cyst. Trophozoites colonizing the large intestine form cysts that are released into the environment. The ingestion of the cysts in contaminated food and water continues the disease cycle. Here, we investigated the role of glycogen in trophozoite growth and encystation. Glycogen is thought to provide precursors for the synthesis of chitin, a major component of the protective cyst wall. We propose that glycogen also serves as an energy source during metabolic adaptation to different nutrient environments. We examined the role of glycogen in by analyzing the growth and encystation of RNAi strains with reduced expression of the single gene-encoding glycogen synthase () or two of three genes encoding glycogen phosphorylase (). The RNAi strain had a greatly reduced glycogen accumulation, and both the and RNAi strains exhibited reduced growth in the glucose-poor medium. Both RNAi strains also showed reduced cyst production. Our results suggest glycogen synthesis and degradation are vital to the growth and adaptation of to a low-glucose environment such as that encountered in the large intestine.
是一种寄生原生动物，每年在全球约1亿人身上引发腹泻疾病。它有两种形态，即生长中的滋养体和具有传染性的包囊。定殖于大肠的滋养体形成包囊，释放到环境中。摄入受污染食物和水中的包囊会延续疾病循环。在此，我们研究了糖原在滋养体生长和包囊化过程中的作用。糖原被认为可为几丁质（保护性包囊壁的主要成分）的合成提供前体。我们提出，在代谢适应不同营养环境的过程中，糖原还可作为能量来源。我们通过分析编码糖原合酶（）的单基因或编码糖原磷酸化酶的三个基因中的两个基因表达降低的RNAi菌株的生长和包囊化情况，研究了糖原在其中的作用。糖原合酶RNAi菌株的糖原积累大幅减少，糖原磷酸化酶1和糖原磷酸化酶2 RNAi菌株在低糖培养基中的生长均受到抑制。两种RNAi菌株的包囊产生也都减少。我们的结果表明，糖原的合成和降解对于在低葡萄糖环境（如在大肠中遇到的环境）中生长和适应至关重要。
