OBJECTIVETo detect and analyze two important genes, comE and luxS, in quorum sensing signal pathway from Streptococcus oralis (S. oralis).

METHODSThe total genomic DNA of S. oralis NH521 (a clinically isolated strain) was firstly extracted. The comE and luxS genes were then amplified by polymerase chain reaction (PCR) and further sequenced. The obtained sequences were compared with related sequences in GenBank.

RESULTSTarget bands of both comE and luxS genes were detected by electrophoresis. The obtained gene sequences were similar to the corresponding sequences from another S. oralis strain (luxS, 95.0%; comE, 99.6%); however, comparing to gene sequences of another species Streptococcus mutans, comE was more divergent (12.7%) than luxS gene (74.1%).

CONCLUSIONThis study successfully amplified and sequenced comE and luxS genes from S. oralis NH521 strain. The luxS gene accumulated more mutations than comE gene did between two S. oralis strains, but comE gene is more divergent than luxS gene between two Streptococcus species.

Bacterial Proteins ; Carbon-Sulfur Lyases ; Polymerase Chain Reaction ; Quorum Sensing ; Signal Transduction ; Streptococcus mutans ; Streptococcus oralis

Bacterial Proteins ; metabolism ; Carbon-Sulfur Lyases ; metabolism ; Mouth ; microbiology ; Quorum Sensing ; Signal Transduction

OBJECTIVEIt is reported that Streptococcus mutans luxS gene may have an important role in the interspecies quorum sensing system. To construct the S. mutans luxS gene knockout mutant, this research aim to construct the luxS gene allelic exchange plasmid.

METHODSThe upstream and downstream flank DNA fragments of S. mutans luxS gene (Xup, Xdn)and the E. coli kanamycin resistance gene (Kana) were enriched by pfu DNA polymerase with "nest PCR" methods. These fragments were ligated into pBluescript SK (+) Phagemids vector with double endonuclease reaction sequentially.

RESULTSWith endonuclease reaction and DNA sequencing, it was proved that the objective plasmid, Xukd-pbsk, was constructed correctively and the kanamycin resistance gene could be expressed in vitro.

CONCLUSIONThe S. mutans luxS gene allelic exchange plasmid is constructed correctively in this research and can be used in the future research of S. mutans luxS gene knockout mutant.

Bacterial Proteins ; Carbon-Sulfur Lyases ; Escherichia coli ; Genetic Vectors ; Plasmids ; Polymerase Chain Reaction ; Quorum Sensing ; Streptococcus mutans

OBJECTIVETo explore the mechanism of virulence regulation in group B streptococcus (BGS) by studying LuxS-related AI-2 quorum-sensing pathway in GBS.

METHODSluxS gene deletion mutants of GBS (Delta lusX) were characterized by reverse transcription (RT)-PCR, colony immunoblot analysis, growth curve measurement, and cAMP determination. Functional analysis of luxS in the deletion mutants was conducted by bioluminescence assay.

RESULTSGenetic analysis results showed that the luxS deletion in the mutant 515-Delta lusX caused upregulation of scpB gene expression. Phenotypic analysis revealed that, in comparison with the wild strain, 515-Delta lusX mutant grew slowly in DCM media but quickly in THY media. An approximately two-fold decrement in bioluminescence was detected in the luxS deletion mutants as compared with the wild strain.

CONCLUSIONThis study confirms the importance of LuxS molecule in the AI-2 quorum-sensing pathway in GBS and provides new insights into the virulence regulation mechanism of GBS.

Bacterial Proteins ; genetics ; Carbon-Sulfur Lyases ; genetics ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Lighting ; Phenotype ; Streptococcus agalactiae ; genetics ; pathogenicity ; Virulence

OBJECTIVETo construct luxS mutant aften luxS gene of Streptococcus mutans (S. mutans) was knocked out, and examine their ability of biofilm formation.

METHODSA recombinant plasmid containing the flanking fragment of luxS of S. mutans was transformed into S. mutans UA159, and selected by brain heart infusion (BHI) agar medium with kanamicin. The luxS mutant further confirmed via polymerase chain reaction (PCR) and the autoinducer-2 (AI-2) bioluminescence assay of Vibrio harveyi (V. harveyi), and ability of luxS mutant and S. mutans UA159 biofilm formation was examined in different phases, in BHI medium with 1% sucrose and 1% glycose by scanning electron microscopy (SEM).

RESULTSLuxS-deficient S. mutans strains were successfully constructed. Compared with S. mutans UA159, the luxS mutant maintained in BHI medium containing 1% sucrose displayed an apparent defect in biofilm formation, while they showed no significant deviation in BHI medium containing 1% glycose.

CONCLUSIONluxS gene in S.mutans can play a role in dental plaque biofilm formation, and the luxS gene is possible to regulate sucrose-dependent biofilm formation.

Bacterial Proteins ; Biofilms ; Carbon-Sulfur Lyases ; Culture Media ; Dental Plaque ; Homoserine ; analogs & derivatives ; Humans ; Lactones ; Streptococcus mutans

Methionine-dependent increase in tumor cells is a specific metabolic defect. This metabolic defect is also a target for selective treatment of cancer. Studies found that the methionine gamma-lyase (methioninase, L-methionine gamma-lyase) can specificly split the methionine of extracellular and intracellular, so it can strongly inhibit the growth of tumor cells and induce apoptosis of tumor cells. However, no effect on normal cells has been found, so the methionine gamma-lyase may play the anti-tumor role. We also explored in the present study another effect of methionine gamma-lyase as a single agent on DNA methylation levels and DNA synthesis, which may change as a result of deprivation of methionine, and thus may enhance anti-tumor effects. Animal studies and clinical trials showed that a variety of methionine dependent methionine gamma-lyase can eliminate the tumor cells. Therefore, methionine restriction is an effective anticancer strategy. Methionine gamma-lyase has shown great prospects as a new type of gene therapy. This article made a review of it.
Animals ; Carbon-Sulfur Lyases ; administration & dosage ; Genetic Therapy ; methods ; Humans ; Neoplasms ; drug therapy ; therapy ; Recombinant Proteins ; administration & dosage ; Transfection

Formaldehyde is a compound which is believed to have had a role in evolutionary processes. On the other hand, the (methyl)glyoxalase pathway is a route being present in all biological organisms whereas its function has not yet been recognized in the biochemical machinery. In this article it is raised that (methyl)glyoxalase path might have functioned as a bridge between formose and archaic reductive citric acid cycles in surface metabolists at the early stage of evolution. According to the theory, formaldehyde was essential for the mentioned system as a raw molecule. Based on thermodynamic calculations a simple way of regulation is also shown. The simplicity of the theory may be in a good agreement with and an explanation of why the (methyl)glyoxalase system is of ubiquitous nature.
Citric Acid Cycle ; Evolution, Chemical* ; Formaldehyde/metabolism* ; Lactoylglutathione Lyase/metabolism* ; Thermodynamics

Annexin A3 ; genetics ; metabolism ; Cells, Cultured ; Guanine Nucleotide Dissociation Inhibitors ; genetics ; metabolism ; Hepatocytes ; drug effects ; metabolism ; Humans ; Lactoylglutathione Lyase ; genetics ; metabolism ; RNA, Messenger ; genetics ; Trichloroethylene ; toxicity ; rho-Specific Guanine Nucleotide Dissociation Inhibitors

Hepatic ischemia/reperfusion (I/R) injury is an inevitable consequence during liver surgery. I/R injury induces serious hepatic dysfunction and failure. In this study, we identified proteins that were differentially expressed between sham and I/R injured livers. Animals were subjected to hepatic ischemia for 1 hr and were sacrificed at 3hr after reperfusion. Serum ALT and AST levels were significantly increased in I/R-operated animals compared to those of sham-operated animals. Ischemic hepatic lobes of I/R-operated animals showed the hepatic lesion with unclear condensation and sinusoidal congestion. Proteins from hepatic tissue were separated using two dimensional gel electrophosresis. Protein spots with a greater than 2.5-fold change in intensity were identified by mass spectrometry. Among these proteins, glutaredoxin-3, peroxiredoxin-3, glyoxalase I, spermidine synthase, dynamin-1-like protein, annexin A4, eukaryotic initiation factor 3, eukaryotic initiation factor 4A-I, 26S proteasome, proteasome alpha 1, and proteasome beta 4 levels were significantly decreased in I/R-operated animals compared to those of sham-operated animals. These proteins are related to protein synthesis, cellular growth and stabilization, anti-oxidant action. Moreover, Western blot analysis confirmed that dynamin-1-like protein levels were decreased in I/R-operated animals. Our results suggest that hepatic I/R induces the hepatic cells damage by regulation of several proteins.
Animals ; Annexin A4 ; Blotting, Western ; Estrogens, Conjugated (USP) ; Eukaryotic Initiation Factor-3 ; Hepatocytes ; Ischemia ; Lactoylglutathione Lyase ; Liver ; Mass Spectrometry ; Mice ; Peptide Initiation Factors ; Proteasome Endopeptidase Complex ; Proteins ; Reperfusion ; Reperfusion Injury ; Salicylamides ; Spermidine Synthase

Hydrogen sulfide (H2S) is the third type of active endogenous gaseous signal molecule following nitric oxide (NO) and carbon monoxide (CO). In mammalians, H2S is mainly synthesized by two proteases, cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE). H2S plays an essential function of physiological regulation in vivo, and promotes penile erection by acting on the ATP-sensitive potassium channels to relax the vascular smooth muscle as well as by the synergistic effect with testosterone and NO to relax the corpus cavernosum smooth muscle (CCSM). At present, the selective phosphodiesterase type 5 (PDE5) inhibitor is mainly used for the treatment of erectile dysfunction (ED), but some ED patients fail to respond. Therefore, further studies on the mechanism of H2S regulating penile erection may provide a new way for the management of erectile dysfunction.
Cystathionine beta-Synthase ; metabolism ; Cystathionine gamma-Lyase ; metabolism ; Humans ; Hydrogen Sulfide ; Male ; Penile Erection