Membraneless microfluidic microbial fuel cell for rapid detection of electrochemical activity of microorganism.

A membraneless microfluidic microbial fuel cell (µMFC) for rapid detection of microorganism electroactivity is demonstrated in this study. Owing to the merit of laminar flow, the proposed µMFC has well-separated anode and cathode without applying proton exchange membrane. The highest open circuit voltages (OCVs) produced by different anodal solutions: fresh medium, inactivated and untreated microflora, were 102, 131, and 246 mV, respectively. These results show that the membraneless µMFC is capable of identifying the electric potential resulting from the imbalanced compositions between two streams (29 mV) and from the electrochemical activity of microflora (115 mV). When samples obtained along a batch cycle of H-type MFC were tested, the membraneless µMFC produced similar OCVs with those from the H-type MFC. In conclusion, the proposed µMFC has comparable abilities in detecting electroactivity with the conventional H-type MFC; moreover, it can distinguish the source of collected electricity.

Biophysical studies of an NAD(P)(+)-dependent aldehyde dehydrogenase from Bacillus licheniformis.

Aldehyde dehydrogenase (ALDH) catalyzes the conversion of aldehydes to the corresponding acids by means of an NAD(P)(+)-dependent virtually irreversible reaction. In this investigation, the biophysical properties of a recombinant Bacillus licheniformis ALDH (BlALDH) were characterized in detail by analytical ultracentrifuge (AUC) and various spectroscopic techniques. The oligomeric state of BlALDH in solution was determined to be tetrameric by AUC. Far-UV circular dichroism analysis revealed that the secondary structures of BlALDH were not altered in the presence of acetone and ethanol, whereas SDS had a detrimental effect on the folding of the enzyme. Thermal unfolding of this enzyme was found to be highly irreversible. The native enzyme started to unfold beyond ~0.2 M guanidine hydrochloride (GdnHCl) and reached an unfolded intermediate, [GdnHCl](05, N-U), at 0.93 M. BlALDH was active at concentrations of urea below 2 M, but it experienced an irreversible unfolding under 8 M denaturant. Taken together, this study provides a foundation for the future structural investigation of BlALDH, a typical member of ALDH superfamily enzymes.

Evaluation of the in vivo anti-inflammatory activity of a flavone glycoside from Cancrinia discoidea (Ledeb.) Poljak.

The anti-inflammatory effect of selagin-7-O-(6″-O-Acetyl-)-ß-D-glucoside, isolated from the medicinal herb Cancrinia discoidea (Ledeb.) Poljak, was evaluated for its anti-inflammatory activity in the carrageenin- and serotonin-induced rat paw oedema models of acute inflammation and the cotton pellet-induced granuloma rat model of chronic inflammation. Flavone glycoside at doses of 5, 10, or 20 mg/kg, the clinical anti-inflammatory indomethacin at 10 mg/kg, or vehicle were administered orally before injection of the pro-inflammatory compound. The test compound showed significant anti-inflammatory activity against paw edema induced by carrageenin or serotonin, most notably at the highest test dose of 20 mg/kg. In the cotton pellet-induced granuloma model, the compound showed dose-dependent anti-inflammatory activity, with the highest effect at 20 mg/kg. In all three assays, the flavone glucoside compound was more active at 20 mg/kg than indomethacin at 10 mg/kg.

[Quantification for biofilm formation of pseudomonas aeruginosa isolates and their genotypic analysis].

OBJECTIVE: To probe the correlation between the ability of biofilm formation of Pseudomonas aeruginosa isolates and their genotypes. METHODS: Forty-eight Pseudomonas aeruginosa isolates were tested for their biofilm formation with a modified microtiter test and were analyzed by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). The percent similarity between their genetic fingerprints and cluster analysis was performed and worked out using computer software. RESULTS: Forty-eight Pseudomonas aeruginosa isolates demonstrated different abilities of biofilm formation in vitro. And the 48 isolates with different abilities of biofilm formation showed different genotypes in fingerprints by ERIC-PCR. Among the 48 isolates of Pseudomonas aeruginosa tested, five clusters (A, B, C, D, E), were identified at the 17% genetic similarity level. The isolates with strong ability of biofilm formation were in D cluster at the 42% genetic similarity level. CONCLUSION: Most of the 48 PA isolates tested formed strong biofilm, and their genotypes were of correlation.

Evaluation of the biofilm-forming ability and genetic typing for clinical isolates of Pseudomonas aeruginosa by enterobacterial repetitive intergenic consensus-based PCR.

Biofilm formation is an important phenotype associated with chronic Pseudomonas aeruginosa infections. In the present study, a total of 48 P. aeruginosa strains isolated from clinical specimens were examined for their biofilm-forming ability using a microtiter plate method. The different biofilm-forming abilities were demonstrated among the strains; however, most strains formed a larger biofilm than strain PAO1, a reference strain. The genetic typing was also carried out by enterobacterial repetitive intergenic consensus-based polymerase chain reaction. Although they were divided into five groups (A to E), most of the strains showing the higher biofilm-forming ability were found to be in groups D and E, suggesting a significant relationship between the biofilm-forming ability and the genetic group.