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Profound screening and evaluation methods for biocide-releasing polymer films are crucial for predicting applicability and therapeutic outcome of these drug delivery systems. For this purpose, we developed an agar overlay assay embedding biopolymer composite films in a seeded microbial lawn. By combining this approach with model-dependent analysis for agar diffusion, antimicrobial potency of the entrapped drug can be calculated in terms of minimum inhibitory concentrations (MICs). Thus, the topical antiseptic 4-hexylresorcinol (4-HR) was incorporated into poly(lactic-co-glycolic acid) (PLGA) films at different loadings up to 3.7 mg/cm² surface area through a solvent casting technique. The antimicrobial activity of 4-HR released from these composite films was assessed against a panel of Gram-negative and Gram-positive bacteria, yeasts and filamentous fungi by the proposed assay. All the microbial strains tested were susceptible to PLGA-4-HR films with MIC values down to 0.4% ( w / w ). The presented approach serves as a reliable method in screening and quantifying the antimicrobial activity of polymer composite films. Moreover, 4-HR-loaded PLGA films are a promising biomaterial that may find future application in the biomedical and packaging sector., Competing Interests: The authors declare no conflict of interest.

A novel mesophilic bacterial strain, designated A-1, was isolated from microbially contaminated biopolymer microcapsules. The bacterium was able to withstand and grow in liquid cultures supplemented with the pyrethroid cypermethrin in concentrations up to 400 mg L(-1) . Furthermore, strain A-1 could use cypermethrin as sole carbon source and could degrade >50% of it in 12 h. Based on phenotypic and chemotaxonomic characterization, and phylogenetic analysis of 16S rRNA gene sequence, the strain A-1 was identified as Methylobacterium sp., which is the first reported cypermethrin degrader of methylotrophic bacteria. A role for esterase activity in cypermethrin biodegradation was presumed. Therefore, the carboxylesterase gene mse1 was amplified from the Methylobacterium sp. strain A-1 genome and the resulting 1 kb amplicon cloned into E. coli. Sequence analysis of the mse1-DNA insert revealed an open reading frame of 633 bp encoding for a putative carboxylesterase of 210 amino acid residues with a predicted molecular mass of 22 kDa. The amino acid sequence of the deduced enzyme MsE1 with the catalytic triad Ser106 , Asp156 , and His187 was found to be similar to that of α/β-hydrolase fold proteins. The active site Ser106 residue is located in the consensus pentapeptide motif Gly-X-Ser-X-Gly that is typical of esterases., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Unlabelled: Imaging of cartilage alterations was attempted in joints of rats with chronic antigen-induced arthritis (AIA) using the cationic 123I-labeled serine proteinase inhibitor antileukoproteinase (123I-ALP; pI > 10), which selectively accumulates in normal cartilage, presumably through interaction with negatively charged proteoglycans., Methods: Iodine-123-ALP or 123I-myoglobin, a control protein of comparable size but with different isoelectric point (pI=7.3) was injected intravenously into normal or AIA rats. Joint accumulation was followed by scintigraphy for 14 hr. Tissue radioactivity was assessed by well-counter measurements after dissection. The content of charged molecules in articular cartilage was determined by toluidine blue staining; the degree of joint destruction was assessed in parallel by x-ray, ex vivo MRI and histopathology., Results: In intact articular cartilage, ALP accumulated to a significantly higher degree than myoglobin. This preferential accumulation was lost in rats with chronic AIA. The target-to-background ratio for 123I-ALP negatively correlated with the loss of toluidine blue staining in cartilage, which documents depletion of charged matrix molecules (r=-0.92, p < 0.01 at 4 hr; r=-0.97, p < 0.01 at 13 hr). ALP scintigraphy was sensitive in detecting cartilage alterations, even though the degree of joint destruction and inflammatory infiltration was mild, as demonstrated by x-ray, MRI and histopathology., Conclusion: In rat AIA, loss of ALP accumulation appears to document proteoglycan depletion in mildly altered arthritic cartilage. ALP scintigraphy may represent a functional assay for early, premorphological cartilage alterations in human arthritis as well.

Previous studies have suggested that endogenous protease inhibitors may participate in the mucosal host defense. Antileukoprotease (ALP) is an important protease inhibitor found on various mucosal surfaces, including those of the respiratory and genital tracts. This study reports on the antimicrobial activity of recombinant (r) ALP toward the human fungal pathogens Aspergillus fumigatus and Candida albicans. rALP expressed pronounced fungicidal activity toward metabolically active A. fumigatus conidia and C. albicans yeast cells; however, metabolically quiescent A. fumigatus conidia were totally resistant. In contrast with the protease inhibitory activity of rALP, the fungicidal activity was localized primarily in the NH2-terminal domain. On a molar base, the fungicidal activity of rALP was comparable with that of human defensins and lysozyme. In addition, rALP caused inhibition of C. albicans yeast cell growth. By exhibiting antifungal activity, ALP may play an important role in the innate mucosal defense against human pathogenic fungi.

Objective: To investigate whether the serine proteinase inhibitor antileukoproteinase (aLP) specifically accumulates in articular and extraarticular cartilage in normal and arthritic rats after intravenous (i.v.) injection., Methods: [123I] or [125I] radiolabeled aLP and a control protein of comparable size were injected iv into normal rats or rats with chronic, antigen induced arthritis (AIA). Joint accumulation of the 2 proteins was followed by scintigraphy and organ tissue radioactivity was assessed by autoradiography and well counter measurements. Immunoprecipitation of aLP from articular cartilage was also performed and the content of charged molecules in normal and arthritic cartilage determined using toluidine blue staining., Results: The accumulation of both radiolabeled aLP and control protein in the normal joint was clearly detectable by scintigraphy, with significant differences between the 2 proteins. In accordance with the scintigraphic data, direct tissue radioactivity measurements, immunoprecipitation, and autoradiography showed highly specific accumulation of radiolabeled aLP in articular and extraarticular cartilage of normal rats. The specific accumulation of aLP in articular cartilage was lost in rats with AIA in parallel with a loss of charged matrix molecules., Conclusion: I.v. injected serine protease inhibitor aLP specifically accumulates in articular and extraarticular cartilage of normal rats. This physiological pathway of cartilage accumulation, lost in proteoglycan depleted arthritic cartilage, may serve to maintain the local balance between proteinase function and inhibition.

Native antileukoproteinase (ALP) and two oxidant resistant mutants ALP 242 and ALP 231 were synthesized by means of recombinant DNA technology. In the ALP 242 molecule the methionine residue located in the reactive centre of the binding loop is replaced by a leucine residue. In ALP 231 all four methionine residues of the second domain were substituted by leucine residues. The native inhibitor and the two oxidant resistant molecules show comparable inhibitory capacities towards human neutrophil elastase (HLE) and cathepsin G. All three inhibitors were treated with different reactive oxygen species. After incubation with chloramine T or supernatants of activated polymorphonuclear leukocytes (PMN's) a drastic drop of inhibitory capacity of the native molecule was observed. Compared to the native form of ALP the mutant ALP 242 was less inactivated, whereas ALP 231 was nearly totally resistant towards all reactive oxygen. (Heinzel-Wieland R. et al., Biomed Biochim Acta 50: 677-681 (1991)) The intratracheal administration of HLE into the lung of Syrian Hamsters induced mild to moderate emphysematous lesions. The inhibitory potencies of native ALP and the ALP mutants were determined in this animal model by means of intratracheal instillation of the different molecules one hour prior to the administration of HLE. The inhibitory effects of ALP 242 and ALP 231 towards HLE-induced emphysema were significantly better than that of the native molecule. Surprisingly no significant differences between the two mutants were observed. (Rudolphus A. et al., Clin Sci 81: 777-784 (1991)) In a second animal model the emphysema was induced by repeated intratracheal administration of lipopolysaccharides (LPS) into the hamster lungs. This model is characterized by a chronic process of inflammation probably caused by a continuous release of endogenous elastase from infiltrating PMN's. Repeated applications of 1 mg of ALP 242 reduced the LPS-induced emphysema by 70 to 80%. In contrast, equal amounts of the native molecule resulted in significantly lower inhibition of the LPS-induced emphysema, only 23-30% reduction was observed. Repeated applications of 1 mg of ALP 231 reduced the LPS-induced emphysema only about 50%. So far it is not yet clear, why the totally oxidant resistant ALP 231 was less effective than the ALP 242 molecule. (Stolk J. et al., Pulmonary Pharmacology in press (1992))

1. Antileucoprotease, being sensitive to oxidative inactivation, can be produced by recombinant techniques. Via site-directed mutagenesis, two mutants of recombinant antileucoprotease were produced in which one or more of the oxidation-sensitive methionine residues were replaced by leucine: in rALP242, methionine-73 was replaced by leucine, and in rALP231, leucine was substituted for four methionine residues. In vitro, native antileucoprotease and the recombinant antileucoprotease preparations have similar inhibitory characteristics towards human neutrophil elastase. We hypothesized that replacement of methionine residues in the antileucoprotease molecule would result in a reduced oxidation sensitivity of the mutants. 2. After incubation of recombinant antileucoprotease and its mutants with increasing dosages of cis-platinum(II)diammine dichloride, we observed that native antileucoprotease and recombinant antileucoprotease were inactivated by this reagent to the same extent. Compared with this, rALP242 was less inactivated, whereas the inhibitory capacity of rALP231 was not influenced by cis-platinum(II)diammine dichloride at all. 3. After incubation of recombinant antileucoprotease, rALP242 and rALP231 with triggered polymorphonuclear leucocytes, which are thought to produce an excess of oxidants, we measured residual inhibitory activities towards human neutrophil elastase of 10%, 55% and 87%, respectively. 4. In vivo, the inhibitory effects of intratracheally administered rALP242 and rALP231 towards human-neutrophil-elastase-induced emphysema were significantly greater than that of recombinant antileucoprotease. There were no significant differences between the mutants.(ABSTRACT TRUNCATED AT 250 WORDS)

Tandem gene plasmids were constructed and used to express inactive proteins equivalent to human antileukoproteinase (ALP) and the variants [Leu73]-ALP and [Leu73, 82, 94, 96]-ALP in E. coli K12. After extraction, refolding, and purification, highly pure and active inhibitors were obtained in good yields. Inhibitory constants for human leukocyte elastase and cathepsin G were found to be similar. The variants in which methionines were exchanged for leucines were shown to be more resistant to inactivation by oxidizing agents than native ALP. As oxidizing conditions exist at sites of inflammation, these ALP variants are promising candidates for therapies involving suppression of elastase-mediated injury.