Destruction of single species biofi lms of Escherichia coli or Klebsiella pneumoniae subsp. pneumoniae by dextranase, lactoferrin, and lysozyme

The aim of this work was to determine the destructive activity of dextranase, lactoferrin, and lysozyme, against single species biofi lms composed of either Klebsiella pneumoniae subsp. pneumoniae or Escherichia coli using the MBEC Assay. Luminescence measurements based on quantitation of the ATP present were used to determine the amount of biofi lm elimination and correlated with quantity of live bacteria present in the sample. The data were analyzed employing a two-way ANOVA and Bonferroni post-test. Treatments resulted in percentage reductions of E. coli biofi lms ranging from 73 to 98 %. Lactoferrin (40 μg/ml) produced a signifi cantly higher-percentage reduction than lysozyme (10 μg/ml) (P < 0.05), no other signifi cant differences occurred. Similar treatments resulted in percentage reductions of K. pneumoniae subsp. pneumoniae biofilms ranging from 51 to 100 %. Dextranase treatments produced a signifi cantly lower percentage reduction than all other materials (P < 0.05), no other signifi cant differences occurred. No material was capable of complete destruction of both single species biofi lms; however, low concentrations of lactoferrin and lysozyme each removed 100 % of the K. pneumoniae subsp. pneumoniae biofi lm. Low concentrations of lactoferrin or lysozyme might be benefi cial to prevent biofi lm formation by K. pneumoniae subsp. pneumoniae. [Int Microbiol 2012; 15(4):183-187

Pemurnian Dan Karakteristik Dextranase Bacteroides Ruminicola Subsp Brevis

The dextranase of B.ruminicola subsp. brevis from bovine rumen has high ability to degrade the D - (1,6) a-glucosidic linkages of dextran substrate. Purification of crude dextranase was done by using ion-exchange chromatography and electrophoresis. It was observed that the purification until ion exchange step by microcrystal cellulose column increased theactivity of dextranase by 400 fold. The purified dextranase was most active at pH 5.5 and 40°C-45°C. The enzyme was strongly inhibited by metal ions such as Cu++,Fe++ and Hg++. The major product in early stage of dextran hydrolysis which were analyzed by paper chromatography showed dextranase of B.ruminicola to be an endotype enzyme

Physiological studies of Leuconostoc mesenteroides strain NRRL B-1149 during cultivation on glucose and fructose media

Glycosyltransferases are extracellular and cell-associated sucrase enzymes produced mainly by lactic acid bacteria Leuconostoc mesenteroides, oral Streptococcus species and also Lactobacillus species. According to the synthesized polymer (glucan or fructan) in the presence of sucrose, these enzymes are divided into two groups: glucosyltransferases (GTFs) and fructosyltransferases (FTFs). Only Streptococcus, Lactobacillus and Leuconostoc strains are known as producers of both GTFs and FTFs. The enzymes from Lactobacillus and Leuconostoc spp. are implicated in the synthesis of polymers and oligosaccharides (OS) important for human health because of their prebiotic properties and immunomodulating activity. In the present work, we studied the production of extracellular and cell-associated glycosyltransferases by Leuconostoc mesenteroides strain NRRL B-1149 during its growth on media containing glucose or fructose as a main carbon source. The enzyme activities, pH and biomass formation were measured and compared during the cultivation. We have shown that glucose and fructose have not an equal role for enzyme production. The highest extracellular activity was detected at the 4th hour during the cultivation of the strain in medium with fructose – 5.45 U/mg. When the strain was cultivated in medium with glucose, the maximum of extracellular enzyme activity was detected at the 5th hour of the cultivation but the measured activity was about 9 times lower compared to these, obtained after cultivation in fructose medium. The studied strain produced mainly extracellular glycosyltransferases in glucose or fructose medium, which were 92.4% and 97.1% of the total enzyme activity, respectively. In order to characterize the produced enzymes, cell-associated and extracellular enzymes were determined using SDS-PAGE and in situ Periodic Acid Schiff′s staining after incubation with 10% sucrose. When the investigated strain was grown in media with sucrose, glucose or fructose, several types of glycosyltransferases were detected – dextransucrase with molecular weight 180 kDa and two fructosyltransferases, corresponding to 120 kDa and 86 kDa molecular weights

Modular ‘Click-in-Emulsion’ Bone-Targeted Nanogels

A new class of nanogel demonstrates modular biodistribution and affinity for bone. Nanogels, ~70 nm in diameter and synthesized via an astoichiometric click-chemistry in-emulsion method, controllably display residual, free clickable functional groups. Functionalization with a bisphosphonate ligand results in significant binding to bone on the inner walls of marrow cavities, liver avoidance, and anti-osteoporotic effects.National Institutes of Health (U.S.) (RO1 DE016516)National Institutes of Health (U.S.) (R01 EB000244)Damon Runyon Cancer Research Foundation (DFS-#2050-10

Biochemical characterization of two GH70 family 4,6-α-glucanotransferases with distinct product specificity from Lactobacillus aviarius subsp. aviarius DSM 20655

Nine GtfB-like 4,6-α-glucanotransferases (4,6-α-GTs) (represented by GtfX of L. aviarius subsp. aviarius DSM 20655) were identified to show distinct characteristics in conserved motifs I-IV. In particular, the "fingerprint" Tyr in motif III of these nine GtfB-type 4,6-α-GTs was found to be replaced by a Trp. In L. aviarius subsp. aviarius DSM20655, a second GtfB-like protein (GtfY), containing the canonical GtfB Tyr residue in motif III, was located directly upstream of GtfX. Biochemical characterization revealed that both GtfX and GtfY showed GtfB-like 4,6-α-GT activity, cleaving (α1→4) linkages and catalyzing the synthesis of (α1→6) linkages. Nonetheless, they differ in product specificity; GtfY only synthesizes consecutive (α1→6) linkages, yielding linear α-glucan products, but GtfX catalyzes the synthesis of (α1→6) linkages predominantly at branch points (22%) rather than in linear segments (10%). The highly branched α-glucan produced by GtfX from amylose V is resistant to digestion by α-amylase, offering great potential as dietary fibers