Dataset Information

A Putative Type II Secretion System Is Involved in Cellulose Utilization in Cytophaga hutchisonii.

ABSTRACT: Cytophaga hutchinsonii is a gliding cellulolytic bacterium that degrades cellulose in a substrate contact-dependent manner. Specific proteins are speculated to be translocated to its extracellular milieu or outer membrane surface to participate in adhesion to cellulose and further digestion. In this study, we show that three orthologous genes encoding the major components (T2S-D, -F, and -G) of type II secretion system (T2SS) are involved in cellulose degradation but not in cell motility. The individual disruption of the three t2s genes results in a significantly retarded growth on cellobiose, regenerated amorphous cellulose, and Avicel cellulose. Enzymatic analyses demonstrate that, whereas the endoglucanase activity of the t2s mutant cells is increased, the ?-glucosidase activity is remarkably reduced compared to that of WT cells. Further analyses reveal that the t2s mutant cells not only exhibit a different profile of cellulose-bound outer membrane proteins from that of wild-type cells, but also display a significant decrease in their capability to adhere to cellulose. These results indicate that a functional link exits between the putative T2SS and cellulose utilization in C. hutchinsonii, and thus provide a conceptual framework to understand the unique strategy deployed by C. hutchinsonii to assimilate cellulose.

SUBMITTER: Wang X

PROVIDER: S-EPMC5553014 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A Putative Type II Secretion System Is Involved in Cellulose Utilization in <i>Cytophaga hutchisonii</i>.

Wang Xia X Han Qingqing Q Chen Guanjun G Zhang Weixin W Liu Weifeng W

Frontiers in microbiology 20170809

<i>Cytophaga hutchinsonii</i> is a gliding cellulolytic bacterium that degrades cellulose in a substrate contact-dependent manner. Specific proteins are speculated to be translocated to its extracellular milieu or outer membrane surface to participate in adhesion to cellulose and further digestion. In this study, we show that three orthologous genes encoding the major components (T2S-D, -F, and -G) of type II secretion system (T2SS) are involved in cellulose degradation but not in cell motility. ...[more]

PMID: 28848505

Similar Datasets

Project description:The type IX secretion system (T9SS), which is involved in pathogenicity, motility, and utilization of complex biopolymers, is a novel protein secretion system confined to the phylum BacteroidetesCytophaga hutchinsonii, a common cellulolytic soil bacterium belonging to the phylum Bacteroidetes, can rapidly digest crystalline cellulose using a novel strategy. In this study, the deletion mutant of chu_0174 (gldN) was obtained using PY6 medium supplemented with Stanier salts. GldN was verified to be a core component of C. hutchinsonii T9SS, and is indispensable for cellulose degradation, motility, and secretion of C-terminal domain (CTD) proteins. Notably, the ΔgldN mutant showed significant growth defects in Ca2+- and Mg2+-deficient media. These growth defects could be relieved by the addition of Ca2+ or Mg2+ The intracellular concentrations of Ca2+ and Mg2+ were markedly reduced in ΔgldN These results demonstrated that GldN is essential for the acquisition of trace amounts of Ca2+ and Mg2+, especially for Ca2+ Moreover, an outer membrane efflux protein, CHU_2807, which was decreased in abundance on the outer membrane of ΔgldN, is essential for normal growth in PY6 medium. The reduced intracellular accumulation of Ca2+ and Mg2+ in the Δ2807 mutant indicated that CHU_2807 is involved in the uptake of trace amounts of Ca2+ and Mg2+ This study provides insights into the role of T9SS in metal ion assimilation in C. hutchinsoniiIMPORTANCE The widespread Gram-negative bacterium Cytophaga hutchinsonii uses a novel but poorly understood strategy to utilize crystalline cellulose. Recent studies showed that a T9SS exists in C. hutchinsonii and is involved in cellulose degradation and motility. However, the main components of the C. hutchinsonii T9SS and their functions are still unclear. Our study characterized the function of GldN, which is a core component of the T9SS. GldN was proved to play vital roles in cellulose degradation and cell motility. Notably, GldN is essential for the acquisition of Ca2+ and Mg2+ ions under Ca2+- and Mg2+-deficient conditions, revealing a link between the T9SS and the metal ion transport system. The outer membrane abundance of CHU_2807, which is essential for Ca2+ and Mg2+ uptake in PY6 medium, was affected by the deletion of GldN. This study demonstrated that the C. hutchinsonii T9SS has extensive functions, including cellulose degradation, motility, and metal ion assimilation, and contributes to further understanding of the function of the T9SS in the phylum Bacteroidetes.

Project description:The type IX secretion system (T9SS) is a novel protein secretion system, which is found in and confined to the phylum Bacteroidetes. T9SS is involved in the secretion of virulence factors, cell surface adhesins, and complex biopolymer degrading enzymes to the cell surface or extracellular medium. Cytophaga hutchinsonii is a widely distributed bacterium, which is able to efficiently digest cellulose and rapidly glide along the solid surfaces. C. hutchinsonii has a full set of orthologs of T9SS components. However, the functions of most homologous proteins have not been verified. In C. hutchinsonii, CHU_0029 and CHU_2709 are similar in sequence to Flavobacterium johnsoniae T9SS components SprA and SprT, respectively. In this study, the single deletion mutants of chu_0029 (sprA) and chu_2709 (sprT) were obtained using a complex medium with the addition of Ca2+ and Mg2+. Single deletion of sprA or sprT resulted in defects in cellulose utilization and gliding motility. Moreover, the ΔsprA and ΔsprT mutants showed growth defects in Ca2+- and Mg2+-deficient media. The results of ICP-MS test showed that both the whole cell and intracellular concentrations of Ca2+ were dramatically reduced in the ΔsprA and ΔsprT mutants, indicating that SprA and SprT are both important for the assimilation of trace amount of Ca2+. While the assimilation of Mg2+ was not obviously influenced in the ΔsprA and ΔsprT mutants. Through proteomics analysis of the cell surface proteins of the wild type and mutants, we found that the ΔsprA and ΔsprT mutants were defective in secretion of the majority of T9SS substrates. Together, these results indicate that SprA and SprT are both essential components of C. hutchinsonii T9SS, which is required for protein secretion, Ca2+ acquisition, cellulose degradation, and gliding motility in C. hutchinsonii. Our study shed more light on the functions of SprA and SprT in T9SS, and further proved the link between the T9SS and Ca2+ uptake system.

Dataset Information

A Putative Type II Secretion System Is Involved in Cellulose Utilization in Cytophaga hutchisonii.

Publications

A Putative Type II Secretion System Is Involved in Cellulose Utilization in <i>Cytophaga hutchisonii</i>.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets