The use of bio-electrochemical systems in environmental remediation of xenobiotics: a review

Summary Remediation of our environment of anthropogenic pollutants has become an imperative of the 21st century in order to sustain human activity and all life on the planet. With the current limitations of the existing technologies for this purpose, the need for innovative bioremediation technologies has become vitally important. Hitherto, electrochemically active microorganisms have only been a scientific curiosity and a platform for sustainable power production from waste material. However, recent research utilizing these electrochemically active microorganisms in Bio-electrochemical systems (BES) has revealed their promising potential for bioremediation applications. The primary research focus of BES applications up-to now has been to optimize and increase their power output. The possibility of utilizing these systems for bioremediation applications has been a new facet of this field of work. This review provides a comprehensive outlook on the utilization of BES based technologies for remediation of xenobiotic environmental pollutants

Genomic and molecular characterization of a novel quorum sensing molecule in Bacillus licheniformis

Quorum sensing molecules (QSMs) are involved in the regulation of complicated processes helping bacterial populations respond to changes in their cell-density. Although the QS gene cluster (comQXPA) has been identified in the genome sequence of some bacilli, the QS system B. licheniformis has not been investigated in detail, and its QSM (ComX pheromone) has not been identified. Given the importance of this antagonistic bacterium as an industrial workhorse, this study was aimed to elucidate B. licheniformis NCIMB-8874 QS. The results obtained from bioinformatics studies on the whole genome sequence of this strain confirmed the presence of essential quorum sensing-related genes. Although polymorphism was verified in three proteins of this cluster, ComQ, precursor-ComX and ComP, the transcription factor ComA was confirmed as the most conserved protein. The cell–cell communication of B. licheniformis NCIMB-8874 was investigated through further elucidation of the ComX pheromone as 13-amino acid peptide. The peptide sequence of the pheromone has been described through biochemical characterisation

A cell engineering strategy to enhance supercoiled plasmid DNA production for gene therapy

With the recent revival of the promise of plasmid DNA vectors in gene therapy, a novel synthetic biology approach was used to enhance the quantity, (yield), and quality of the plasmid DNA. Quality was measured by percentage supercoiling and supercoiling density, as well as improving segregational stability in fermentation. We examined the hypothesis that adding a Strong Gyrase binding Site (SGS) would increase DNA gyrase-mediated plasmid supercoiling. SGS from 3 different replicons, (the Mu bacteriophage and two plasmids, pSC101 and pBR322) were inserted into the plasmid, pUC57. Different sizes of these variants were transformed into E. coli DH5α, and their supercoiling properties and segregational stability measured. A 36% increase in supercoiling density was found in pUC57-SGS, but only when SGS was derived from the Mu phage and was the larger sized version of this fragment. These results were also confirmed at fermentation scale. Total % supercoiled monomer was maintained to 85-90%. A two-fold increase in plasmid yield was also observed for pUC57-SGS in comparison to pUC57. pUC57-SGS displayed greater segregational stability than pUC57-cer and pUC57, demonstrating a further potential advantage of the SGS site. These findings should augment the potential of plasmid DNA vectors in plasmid DNA manufacture. This article is protected by copyright. All rights reserved

Pichia pastoris (Komagataella phaffii) as a Cost-Effective Tool for Vaccine Production for Low- and Middle-Income Countries (LMICs)

Vaccination is of paramount importance to global health. With the advent of the more recent pandemics, the urgency to expand the range has become even more evident. However, the potential limited availability and affordability of vaccines to resource low‐ and middle‐income countries has created a need for solutions that will ensure cost‐effective vaccine production methods for these countries. Pichia pastoris (P. pastoris) (also known as Komagataella phaffii) is one of the most promising candidates for expression of heterologous proteins in vaccines development. It combines the speed and ease of highly efficient prokaryotic platforms with some key capabilities of mammalian systems, potentially reducing manufacturing costs. This review will examine the latest developments in P. pastoris from cell engineering and design to industrial production systems with focus on vaccine development and with reference to specific key case studies

DESIGNING A COMPETITIVE ADVANTAGE MODEL WITH TECHNOLOGY ORIENTED APPROACH USING FAHP TECHNIQUE: A CASE STUDY IN COIL INDUSTRY

One of the distinctive attributes of today’s successful companies is having at least one competitive advantage in one known area. Technological competency is an important advantage which helps improve the firm’s competitiveness. In fact, suitable use of new technologies can dramatically influence the innovation speed, decrease the time of product development cycle and also increase the rate of new product introduction. Firm-specific technological competencies help explain why a firm is different, how it changes over time, and whether it is capable of remaining competitive. In this study, technological competency factors (technology management, process technology, product technology) are prioritized according to the competitive advantage levels(customer satisfaction, brand reputation, new product introduction, market share) and competitive priorities (cost, price, quality, flexibility, time) using fuzzy Analytic hierarchy process (FAHP) with the aim of maximizing the nonfinancial performance at coil manufacture industry. The results indicate that within Iran coil industry, process technology is of greater importance than technology management and product technology

Improving Fab’ fragment retention in an autonucleolytic Escherichia coli strain by swapping periplasmic nuclease translocation signal from OmpA to DsbA

OBJECTIVES: To reduce unwanted Fab’ leakage from an autonucleolytic Escherichia coli strain, which co-expresses OmpA-signalled Staphylococcal nuclease and Fab’ fragment in the periplasm, by substituting in Serratial nuclease and the DsbA periplasm translocation signal as alternatives. RESULTS: We attempted to genetically fuse a nuclease from Serratia marcescens to the OmpA signal peptide but plasmid construction failed, possibly due to toxicity of the resultant nuclease. Combining Serratial nuclease to the DsbA signal peptide was successful. The strain co-expressing this nuclease and periplasmic Fab’ grew in complex media and exhibited nuclease activity detectable by DNAse agar plate but its growth in defined medium was retarded. Fab’ coexpression with Staphylococcal nuclease fused to the DsbA signal peptide resulted in cells exhibiting nuclease activity and growth in defined medium. In cultivation to high cell density in a 5 l bioreactor, DsbA-fused Staphylococcal nuclease co-expression coincided with reduced Fab’ leakage relative to the original autonucleolytic Fab’ strain with OmpA-fused staphylococcal nuclease. CONCLUSIONS: We successfully rescued Fab’ leakage back to acceptable levels and established a basis for future investigation of the linkage between periplasmic nuclease expression and leakage of co-expressed periplasmic Fab’ fragment to the surrounding growth media

Influence of Pichia pastoris cellular material on polymerase chain reaction performance as a synthetic biology standard for genome monitoring

Advances in synthetic genomics are now well underway in yeasts due to the low cost of synthetic DNA. These new capabilities also bring greater need for quantitating the presence, loss and rearrangement of loci within synthetic yeast genomes. Methods for achieving this will ideally; i) be robust to industrial settings, ii) adhere to a global standard and iii) be sufficiently rapid to enable at-line monitoring during cell growth. The methylotrophic yeast Pichia pastoris (P. pastoris) is increasingly used for industrial production of biotherapeutic proteins so we sought to answer the following questions for this particular yeast species. Is time-consuming DNA purification necessary to obtain accurate end-point polymerase chain reaction (e-pPCR) and quantitative PCR (qPCR) data? Can the novel linear regression of efficiency qPCR method (LRE qPCR), which has properties desirable in a synthetic biology standard, match the accuracy of conventional qPCR? Does cell cultivation scale influence PCR performance? To answer these questions we performed e-pPCR and qPCR in the presence and absence of cellular material disrupted by a mild 30s sonication procedure. The e-pPCR limit of detection (LOD) for a genomic target locus was 50 pg (4.91 × 103 copies) of purified genomic DNA (gDNA) but the presence of cellular material reduced this sensitivity sixfold to 300 pg gDNA (2.95 × 104 copies). LRE qPCR matched the accuracy of a conventional standard curve qPCR method. The presence of material from bioreactor cultivation of up to OD600 = 80 did not significantly compromise the accuracy of LRE qPCR. We conclude that a simple and rapid cell disruption step is sufficient to render P. pastoris samples of up to OD600 = 80 amenable to analysis using LRE qPCR which we propose as a synthetic biology standard

Share of nations in 37 international public health journals : an equity and diversity perspective towards health research capacity building.

Background: This paper contributes to further exploration of inequity in access to health research capacity development by examining the representation of different nations in international public health journals. It also aims to examine the degree of diversity that exists in these journals.Methods: This study is a descriptive survey. It was done with objective sampling on 37 ISI health journals on October of 2008.The number and nationality of people in different editorial positions of the journals was identified. The second analy­sis involved recalculating the numbers obtained for each nation to the population size of nations per million inhabitants. In order to better compare countries in terms of presence in editorial team of the journals, a ‘public health editor equity gap ratio' (PHEEGR) was developed.Results: Low income countries have occupied none of the leadership positions of chief editor or associate /assistant chief editors and middle income countries at maximum shared less than 5 percent. The PHEEGR gap in access to the different editorial positions between highest to the lowest representation of countries was 16/1 for chief editors, 12/1 for associate editors , 335/1 for editorial boards and 202/1 for associate editorial boards. However, after normalizing the data to the country's population, the gap increased significantly.Conclusion: There is an imbalance and possibly even inequity in the composition of editorial boards and offices of interna­tional health journals that should be paid significant attention. This can contribute to fill the equity gap exists between health in developing and developed countries

Application of Magnetic Field for Improvement of Microbial Productivity

Continued attempt by the industry and research sectors to improve productivity of commercially viable microbial products fall into three general approaches including microbial-based (e.g. isolation, selection, and manipulation of microbes as higher producers), environmental-based (e.g. media development), and bioreactor/bioprocessbased studies. Application of electromagnetic field to microbial cultures is a recent bioprocess-based technique. Current literature shows some effects on characteristics of microbial species (fungi and bacteria). These include enhancement of ethanol production capacity of Saccharomyces cerevisiae, citric acid and cellulase production by Aspergillus niger species and insulase production by Geotrichum candidum after the cultures were exposed to electromagnetic field. In this paper we report the application of electromagnetic field to cultures of Bacillus licheniformis to enhance productivity of bacitracin, a water-soluble branched polypeptide used as an antimicrobial agent against grampositive and some gram-negative bacteria. Electromagnetic field was applied on cultures of B. licheniformis in stirred tank reactors (STRs) with working volume of 1.5 litres circulating into an in-house designed and constructed magnetic field generator with low magnetic field intensity. The experiments were carried out both with and without pH control of the culture. Samples were assayed for bacitracin concentration to confirm the effects of electromagnetic field. The microbial growth and pH profiles were also monitored. The results showed that circulation of culture at flow rate of 10 mL.min-1 into magnetic field with 10 millitesla intensity leads to an increase in bacitracin concentration. The increase was higher when the pH of the culture was controlled compared to non-controlled culture. The highest percentage increase in bacitracin concentration was 36 % after 35 hours without pH control, while the highest bacitracin percentage increase obtained from the controlled culture under pH 7 exposed to electromagnetic field, was almost 89 % after 43 hours