Overview of approval procedures for bioadhesives in the United States of America and Canada.

Bioadhesives are useful medical devices to help reduce postoperative complications and as adjuncts to sutures and staples in sealing wounds. Biomedical companies have been promoting research and development into new bioadhesives. As for other medical devices, translating promising candidates to market involves the need to pass through several regulatory steps, wherein their safety and effectiveness are evaluated and the proper reimbursements from payors are assessed.

Advances and challenges in the production of extracellular thermoduric pullulanases by wild-type and recombinant microorganisms: a review.

Thermoduric pullulanases, acting as starch-debranching enzymes, are required in many industrial applications, mainly in the production of concentrated glucose, maltose, and fructose syrups. To date, however, a single pullulanase, from Bacillus acidopullulyticus, is available on the market for industrial purposes. This review is an investigation of the major advances as well as the major challenges being faced with regard to optimization of the production of extracellular thermoduric pullulanases either by their original hosts or by recombinant organisms.

Optimization of the production of an extracellular and thermostable amylolytic enzyme by Thermus thermophilus HB8 and basic characterization.

The objective of this study was to determine the potential of Thermus thermophilus HB8 for accumulating a high level of extracellular, thermostable amylolytic enzyme. Initial production tests indicated clearly that only very low levels of amylolytic activity could be detected, solely from cells after extraction using the mild, non-ionic detergent Triton X-100. A sequential optimization strategy, based on statistical designs, was used to enhance greatly the production of extracellular amylolytic activity to achieve industrially attractive enzyme titers.

High-yield soluble expression and simple purification of the antimicrobial peptide OG2 using the intein system in Escherichia coli.

OG2 is a modified antimicrobial peptide, that is, derived from the frog peptide Palustrin-OG1. It has high antimicrobial activity and low cytotoxicity, and it is therefore promising as a therapeutic agent. Both prokaryotic (Escherichia coli) and eukaryotic (Pichia pastoris) production host systems were used to produce OG2 in our previous study; however, it was difficult to achieve high expression yields and efficient purification.

Effects of amino acid deletion and substitution on the chemical properties, biological activities of the frog peptide palustrin-OG1.

Palustrin-OG1 (OG1) is a host defense peptide isolated from the frog Odorrana grahami. In this study, we analyzed the chemical properties, antimicrobial activities and cytotoxicities of OG1 and its derivatives to identify the most promising peptide as an antimicrobial agent. By increasing the net positive charge, amphipathicity and decreasing the mean hydrophobicity of OG1, the derivative named as OG2 exerted higher antimicrobial activity against bacteria but lower cytotoxicity against both porcine erythrocytes and peripheral blood mononuclear cells than did OG1 (P<0.

Effects of thioredoxin: SUMO and intein on soluble fusion expression of an antimicrobial peptide OG2 in Escherichia coli.

OG2 is a modified antimicrobial peptide of Palustrin-OG1 (OG1), which is derived from Odorrana grahami frog. OG2 has shown much higher selective antimicrobial activity and lower hemolytic activity than OG1, indicating OG2 may be a promising antimicrobial agent. In this study, we investigated three fusion partners, including thioredoxin, Mxe GyrA intein, and small ubiquitin-like modifier (SUMO), each fused with OG2, and examined their effects on the expression level and solubility of OG2 in Escherichia coli.

Introducing a new bioengineered bug: Methylobacterium extorquens tuned as a microbial bioplastic factory.

Discussion on and use of methanol as chemical feedstock and as alternative fuel has gained momentum during the past years. Consequently, microorganism and product design based on ''methylotrophism'' is in vogue as reflected by increasing research and development activities in methanol-related areas. A recent example of microorganism and product development is the use of recombinant Methylobacterium extorquens ATCC 55366 strains in the production of second generation biopolyesters.

Production of functionalized polyhydroxyalkanoates by genetically modified Methylobacterium extorquens strains.

Background: Methylotrophic (methanol-utilizing) bacteria offer great potential as cell factories in the production of numerous products from biomass-derived methanol. Bio-methanol is essentially a non-food substrate, an advantage over sugar-utilizing cell factories. Low-value products as well as fine chemicals and advanced materials are envisageable from methanol.

Novel, versatile, and tightly regulated expression system for Escherichia coli strains.

A novel tightly regulated gene expression system was developed for Escherichia coli by applying the regulatory elements of the Pseudomonas putida F1 cym and cmt operons to control target gene expression at the transcriptional level by using p-isopropylbenzoate (cumate) as an inducer. This novel expression system, referred to as the cumate gene switch, includes a specific expression vector, pNEW, that contains a partial T5 phage promoter combined with the Pseudomonas-based synthetic operator and the cymR repressor protein-encoding gene designed to express constitutively in the host strain. The induction of transcription relies on the addition of the exogenous inducer (cumate), which is nontoxic to the culture, water soluble, and inexpensive.

Production of an insecticidal crystal protein from Bacillus thuringiensis by the methylotroph Methylobacterium extorquens.

The Cry1Aa protein from Bacillus thuringiensis is an insecticidal protein that is highly active against several species of Lepidoptera. We cloned and expressed the cry1Aa gene in a plant-colonizing methylotroph, Methylobacterium extorquens, under the control of the strong M. extorquens AM1 methanol dehydrogenase promoter, P(mxaF).

Production of active pediocin PA-1 in Escherichia coli using a thioredoxin gene fusion expression approach: cloning, expression, purification, and characterization.

Antimicrobial peptides possess cationic and amphipathic properties that allow for interactions with the membrane of living cells. Bacteriocins from lactic acid bacteria, in particular, are currently being studied for their potential use as food preservatives and for applications in health care. However, bacteriocin exploitation is often limited owing to low production yields.

Diversity of soluble methane monooxygenase-containing methanotrophs isolated from polluted environments.

Methanotrophs were enriched and isolated from polluted environments in Canada and Germany. Enrichments in low copper media were designed to specifically encourage growth of soluble methane monooxygenase (sMMO) containing organisms. The 10 isolates were characterized physiologically and genetically with one type I and nine type II methanotrophs being identified.

Multicopy integration and expression of heterologous genes in Methylobacterium extorquens ATCC 55366.

High-level expression of chromosomally integrated genes in Methylobacterium extorquens ATCC 55366 was achieved under the control of the strong M. extorquens AM1 methanol dehydrogenase promoter (PmxaF) using the mini-Tn7 transposon system. Stable maintenance and expression of the integrated genes were obtained in the absence of antibiotic selective pressure.

Microbial resolution of baclofen by a new isolate of Streptomyces halstedii.

We attempted to isolate microorganisms able to metabolize (S)-baclofen while showing little or no activity with (R)-baclofen. A culture collection of 218 microbial isolates was established from several soil samples using various approaches. Subsequent chiral HPLC analysis revealed that only two cultures showed promise.

An improved and simplified method for the large-scale purification of pediocin PA-1 produced by Pediococcus acidilactici.

The bacteriocin pediocin PA-1 produced by Pediococcus acidilactici PAC 1.0 offers significant potential as a food preservative and as an antimicrobial agent in the medical area. However, low production yields and difficulties in obtaining significant amounts of pure pediocin PA-1 have limited, in part, its biochemical and physical characterization.

Production of pediocin PA-1 in the methylotrophic yeast Pichia pastoris reveals unexpected inhibition of its biological activity due to the presence of collagen-like material.

Expression of the pedA gene from Pediococcus acidilactici, coding for mature bacteriocin Pediocin PA-1, was investigated using the yeast Pichia pastoris to obtain larger quantities of pediocin to support additional studies, including structure-function research. Following various cloning strategies, a KM71H (Mut(s)) strain was selected. A significant concentration (74 microg/ml) of extracellular recombinant pediocin was obtained but the pediocin showed no biological activity.

Detection of methanotrophs with highly divergent pmoA genes from Arctic soils.

Tundra soil samples from the Canadian Arctic community, Kuujjuaq, were analyzed for the presence of the soluble (sMMO) and particulate (pMMO) methane monooxygenase genes. Total genomic DNA extracted from these soils was used as template for PCR using sMMO- and pMMO-specific primers, mmoX1-mmoX2 and A189-A682, respectively. pMMO and sMMO genes were detected in the Kuujjuaq soil samples.