Journal of Microbiology

Journal Article

GPH1 is involved in glycerol accumulation in the three-dimensional networks of the nematode-trapping fungus Arthrobotrys oligospora: Qin-Yi Wu , Yue-Yan Zhu , Cheng-Gang Zou , Ying-Qian Kang , Lian-Ming Liang; J. Microbiol. 2016;54(11):768-773. Published online October 29, 2016; DOI: https://doi.org/10.1007/s12275-016-6272-8

Abstract: Turgor is very important for the invasive growth of fungal pathogens. Glycerol, a highly osmotic solvent, is considered to play an important role in turgor generation. The nematophagous fungus Arthrobotrys oligospora mainly lives as a saprophyte. In the presence of nematodes, A. oligospora enters the parasitic stage by forming three-dimensional networks (traps) to capture nematodes. In A. oligospora, we found that glycerol accumulated during nematode-induced trap formation. We demonstrated that deleting gph1, which encodes glycogen phosphorylase, decreased the glycerol content, compared with that of a wild-type strain. Although the number of traps induced by nematodes was not affected in the Δgph1 mutant, the capture rate was lower. Meanwhile, deleting gph1 also affected the growth rate and conidiation capacity of the fungus. These results indicate that glycerol derived from GPH1 is essential for the full virulence of A. oligospora against nematodes.

Regulation of Glycogen Concentration by the Histidine-Containing Phosphocarrier Protein HPr in Escherichia coli: Byoung-Mo Koo , Yeong-Jae Seok; J. Microbiol. 2001;39(1):24-30.

Abstract: In addition to effecting the catalysis of sugar uptake, the bacterial phosphoenolpyruvate:sugar phosphotransferase system regulates a variety of physiological processes. In a previous paper [Seok et al., (1997) J. Biol. Chem. 272, 26511-26521], we reported the interaction with and allosteric regulation of Escherichia coli glycogen phosphorylase activity by the histidine-containing phosphocarrier protein HPr in vitro. Here, we show that the specific interaction between HPr and glycogen phosphorylase occurs in vivo. To address the physiological role of the HPr-glycogen phosphorylase complex, intracellular glycogen levels were measured in E. coli strains transformed with various plasmids. While glycogen accumulated during the transition between exponential and stationary growth phases in wildtype cells, it did not accumulate in cells overproducing HPr or its inactive mutant regardless of the growth stage. From these results, we conclude that HPr mediates crosstalk between sugar uptake through the phosphoenolpyruvate:sugar phosphotransferase system and glycogen breakdown. The evolutionary significance of the HPr-glycogen phosphorylase complex is suggested.

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