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Liuyu Huang

Publications and source records attributed to Liuyu Huang.

9 recordsLinked to original sources
PubMed2006

A proteome reference map and proteomic analysis of Bifidobacterium longum NCC2705.

A comprehensive proteomic study was carried out to identify and characterize proteins expressed by Bifidobacterium longum NCC2705. A total of 708 spots representing 369 protein entries were identified by MALDI-TOF-MS and/or ESI-MS/MS. Isoelectric point values estimated by gel electrophoresis matched closely with their predicted ones, although some discrepancies exist suggesting that post-translational protein modifications might be common in B. longum. The identified proteins represent 21.4% of the predicted 1727 ORFs in the genome and correspond to 30% of the predicted proteome. Moreover 95 hypothetical proteins were experimentally identified. This is the first compilation of a proteomic reference map for the important probiotic organism B. longum NCC2705. The study aimed to define a number of cellular pathways related to important physiological processes at the proteomic level. Proteomic comparison of glucose- and fructose-grown cells revealed that fructose and glucose are catabolized via the same degradation pathway. Interestingly the sugar-binding protein specific to fructose (BL0033) and Frk showed higher levels of expression in cells grown on fructose than on glucose as determined by semiquantitative RT-PCR. BL0033 time course and concentration experiments showed that the induction time and fructose concentration correlates to increased expression of BL0033. At the same time, an ABC (ATP-binding cassette) transporter ATP-binding protein (BL0034) was slightly up-regulated in cells grown on fructose compared with glucose. All of the above results suggest that the uptake of fructose into the cell may be conducted by a specific transport system in which BL0033 might play an important role.

ATP-Binding Cassette Transporters↗
PubMed2005

2-D reference map of Bacillus anthracis vaccine strain A16R proteins.

Bacillus anthracis has always been an important pathogen because it can cause lethal inhalational anthrax, and may be used as a bioweapon or by bioterrorists. In this study, a 2-DE reference map and database of B. anthracis A16R was constructed. In total, 534 spots were processed, and 406 spots representing 299 proteins were identified. Gel-estimated pIs and molecular masses mostly matched well with their theoretical predictions, but some discrepancies also existed. Spot and protein corresponding analysis revealed that post-translational modifications might be common in B. anthracis. Through the MASCOT search, the similarity of B. anthracis, B. cereus and B. thuringiensis was further verified by protein level and a possible annotation error in B. anthracis strain Ames 0581 genome was found. Proteins of energy metabolism, fatty acid and phospholipid metabolism, protein synthesis, and cellular processes represented a large part of the most abundant proteins. At the same time, 27 hypothetical proteins were experimentally proved. There were 28 proteins also identified as spore composition in recently spore-related research, which indicated that they might play some roles in different phases such as growth, sporulation and outgrowth. Maps and information about all identified proteins are available on the Internet at http://www.mpiib-berlin.mpg.de/2D-PAGE and http://www.proteomics.com.cn.

Anthrax Vaccines↗
PubMed2005

Immunoproteomics of outer membrane proteins and extracellular proteins of Shigella flexneri 2a 2457T.

Shigella flexneri 2a is an important pathogen causing bacillary dysentery in humans. In order to investigate any potential vaccine candidate proteins present in outer membrane proteins (OMPs) and extracellular proteins of S. flexneri 2a 2457T, we use the proteome mapping and database analyzing techniques. A subproteome map and database of OMPs were established first. One hundred and nine of the total 126 marked spots were cut out and processed to MALDI-TOF-MS and PMF. Eighty-seven spots were identified and they represented 55 OMP entries. Furthermore, immunoproteomics analysis of OMPs and extracellular proteins were performed. Total of 34 immunoreactive spots were identified, in which 22 and 12 were from OMPs and extracellular proteins, respectively. Eight novel antigens were found and some of these antigens may be potential vaccine candidate proteins. These results are useful for future studying of pathogenicity, vaccine, and novel antibacterial drugs. Maps and tables of all identified proteins are available on the Internet at www.proteomics.com.cn.

Bacterial Outer Membrane Proteins↗
PubMed2004

Screening and identification of Shigella flexneri 2a virulence-related genes induced after invasion of epithelial cells.

An in vivo expression technology (IVET) was applied to screen S. flexneri 2a genes induced after invasion of epithelial cells, and virulence-related genes were further identified by mutational analysis. Thirteen intracellular induced genes were identified with a HeLa cell infection model. Of these, two were identified as alkylation-related genes; one was related to metabolism; one encoded a transcriptional regulator; three were identified as insertion elements; three appeared to be antisense to genes involved in the transmethylation, biosynthesis, and phosphotransferase system; and three were predicted to encode polypeptides with unknown functions. Intracellular survival assays showed that the mutants of alkA, citC and wcaJ genes had lower capability of intracellular replication or survival than the wild-type strain. The results indicated that alkA, citC and wcaJ genes could take part in the intracellular survival or replication of S. flexneri 2a and the capability of intracellular survival or replication could be one of the major virulence elements. However, the yaiC mutant was able to survive in the murine infection assay but almost not in HeLa cell infection assay. Very possibly, yaiC gene was involved in the other mechanism of S. flexneri virulence. This study might lead to a better understanding of the intracellular survival or proliferation process of S. flexneri 2a and perhaps provide insights into the pathogenicity of this pathogen.

Animals↗
PubMed2003

A two-dimensional proteome map of Shigella flexneri.

Shigella flexneri is a Gram-negative facultatively intracellular pathogen responsible for bacillary dysentery in humans. In this study, extracellular proteins from the culture medium and whole cell proteins in cellular extracts of S. flexneri 2a strain 2457T were examined by two-dimensional (2-D) gel electrophoresis using immobilized pH gradient (IPG) technology. Proteins were identified by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) in combination with Mascot search program. In total, among the 488 proteins spots processed, 388 proteins were identified. The identified proteins represented 169 genes. By comparing results of Mascot search against databases of Escherichia coli and genomes of S. flexneri 2a, one S. flexneri-specific protein was identified and one possible gap was found in 2457T genome sequences. Although this proteome map is still incomplete, it is already a useful reference for future studies involving pathogenicity, vaccine development, design of novel antibacterial drugs, etc. Proteome maps and a table of all identified proteins are available on the internet at www.proteomics.com.cn.

Bacterial Proteins↗
PubMed2003

[Study on gene knockout using red system in Shigella flexneri].

The technology of gene knockout using lambda Red system in bacteria has been developed lately, but its application being limited to Esherichia coli. In order to get some experiences in other bacteria we select four genes, including alkA, wcaJ, yphF and dam, to test gene knockout using Red system in E. coli and Shigella. As a result, three genes were successfully knocked out in E. coli except dam while only alkA gene was knocked out in Shigella. It showed that the Red system should be improved if it was to be effectively used in Shigella and other bacteria.

Bacterial Proteins↗
PubMed2003

[Cloning of ipaB gene from Shigella flexneri and its expression in yeast cell].

ipaB gene amplified from S. flexneri 2a by PCR was cloned into pGBKT7 vector (Named pGBKT-ipaB) and sequencing indicated that the amino encoded by the cloned gene was the same as the reported; The recombination plasmid pGBKT-ipaB was transformed into the yeast strain AH109, in which the fusion expression of IpaB was analyzed with SDS-PAGE and Western blotting. This provided the basis for screening the interacting protein with IpaB by two hybrid system and understanding the function of IpaB in the pathogenesis of S. flexneri further.

Bacterial Proteins↗
PubMed2002

[Studies on hydantoinase producing conditions of Arthrobacter K1108].

The hydantoinase-producing conditions from strain Arthrobacter K1108 were investigated. It is shown that the hydantoinase in the strain is intracellular and inducible. Its optimal inducer is 5-benzylhydantoin, while 5-indolylmethylhydantoin and 5-phenylhydantoin cannot induce the production of hydantoinase in K1108. A gratuitous inducer was designed, with which the hydantoinase production is 343% as much as that with 5-benzylhydantoin. The media for culturing the bacteria were screened and optimized. Under optimal conditions, the specific activity of K1108 cells reached 10.8 U/mL.

Amidohydrolases↗