Interleukin-8 Responses of Multi-Layer Gingival Epithelia to Subgingival Biofilms: Role of the “Red Complex” Species

Periodontitis is an infectious inflammatory disease that results in the destruction of the tooth-supporting (periodontal) tissues. The Gram-negative anaerobic species Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola, (also known as the “red complex” species) are highly associated with subgingival biofilms at periodontitis-affected sites. A major chemokine produced by the gingival epithelium in response to biofilm challenge, is interleukin (IL)-8. The aim of this in vitro study was to investigate the relative effect of the “red complex” species as constituents of subgingival biofilms, on the regulation of IL-8 by gingival epithelia. Multi-layered organotypic human gingival epithelial cultures were challenged with a 10-species in vitro subgingival biofilm model, or its 7-species variant, excluding the “red complex”. IL-8 gene expression and secretion analyses were performed by qPCR and ELISA, respectively. After 3 h, both biofilms up-regulated IL-8 gene expression, but the presence of the “red complex” resulted in 3-fold greater response. IL-8 secretion was also up-regulated by both biofilms, with no differences between them. After 24 h, the 10-species biofilm reduced IL-8 secretion to 50% of the control, but this was not affected when the “red complex” was absent. In conclusion, as part of biofilms, “red complex” species differentially regulate IL-8 in gingival epithelia, potentially affecting the chemotactic responses of the tissue.     

Cloning, expression, purification and characterization of fructose-1,6-bisphosphate aldolase from Anoxybacillus gonensis G2

The fructose-1,6-bisphosphate aldolase gene from the thermophilic bacterium, Anoxybacillus gonensis G2, was cloned and sequenced. Nucleotide sequence analysis revealed an open reading frame coding for a 30.9 kDa protein of 286 amino acids. The amino acid sequence shared approximately 80-90% similarity to the Bacillus sp. class II aldolases. The motifs that are responsible for the binding of a divalent metal ion and catalytic activity completely conserved. The gene encoding aldolase was overexpressed under T7 promoter control in Escherichia coli and the recombinant protein purified by nickel affinity chromatography. Kinetic characterization of the enzyme was performed at 60 degrees C, and K(m) and V(max) were found to be 576 microM and 2.4 microM min(-1) mg protein(-1), respectively. Enzyme exhibits maximal activity at pH 8.5. The activity of enzyme was completely inhibited by EDTA.     

Comparative evaluation of biogas production from dairy manure and co‐digestion with maize silage by CSTR and new anaerobic hybrid reactor

This study aimed to investigate potential methane production through anaerobic digestion of dairy manure and co‐digestion with maize silage. Two different anaerobic reactor configurations (single‐stage continuously stirred tank reactor [CSTR] and hybrid anaerobic digester) were used and biogas production performances for each reactor were compared. The HR was planned to enable phase separation in order to improve process stability and biogas production under higher total solids loadings (≥4%). The systems were tested under six different organic loading rates increased steadily from 1.1 to 5.4 g VS/L.d. The CSTR exhibited lower system stability and biomass conversion efficiency than the HR. The specific biogas production of the hybrid system was between 440 and 320 mL/gVS with 81–65% volatile solids (VS) destruction. The hybrid system provided 116% increase in specific biogas production and VS destruction improved by more than 14%. When MS was co‐digested together with dairy manure, specific biogas production rates increased about 1.2‐fold. Co‐digestion was more beneficial than mono‐material digestion. The hybrid system allowed for generating methane enriched biogas (>75% methane) by enabling phase separation in the reactor. It was observed that acidogenic conditions prevailed in the first two compartments and the following two segments as methanogenic conditions were observed. The pH of the acidogenic part ranged between 4.7 and 5.5 and the methanogenic part was between 6.8 and 7.2.     

Proteomic analysis of the fish pathogen <Emphasis Type="Italic">Flavobacterium columnare</Emphasis>

Background  

Flavobacterium columnare causes columnaris disease in cultured and wild fish populations worldwide. Columnaris is the second most prevalent bacterial disease of commercial channel catfish industry in the United States. Despite its economic importance, little is known about the expressed proteins and virulence mechanisms of F. columnare. Here, we report the first high throughput proteomic analysis of F. columnare using 2-D LC ESI MS/MS and 2-DE MALDI TOF/TOF MS.