Williopsis saturnus yeast killer toxin does not kill Streptococcus pneumoniae

Streptococcus pneumoniae is an important human bacterial pathogen, and the increase in antibiotic resistance demands the development of new antimicrobial compounds. Several reports have suggested that yeast killer toxins show activity against bacteria and we therefore investigated the activity of K9 killer toxin from the yeast Williopsis saturnus var. mrakii NCYC 500 against S. pneumoniae. However, no inhibition of bacterial growth was observed with concentrated K9 preparations in agar diffusion assays and in liquid culture. Although cell morphology was slightly affected by K9 treatment, no effect on cellular viability was detectable, and K9 had no stimulatory effect on cell lysis induced by β-lactams or Triton X-100. This indicated that K9 did not contribute to cell wall damage. Moreover, flow cytometry was used as a sensitive assessment of integrity of cells exposed to killer toxin. No significant damage of S. pneumoniae cells was evident, although minor changes in fluorescence suggested that K9 killer toxin may interact with bacterial surface components

The antimicrobial activity of oil-in-water microemulsions is predicted by their position within the microemulsion stability zone

It has been shown previously that thermodynamically stable oil-in-water microemulsions have significant antimicrobial activity against planktonic cells and biofilm cells over short periods of exposure. It was the aim of this study to identify whether the position of the microemulsion within the microemulsion stability zone of the pseudo-ternary phase structure predicts the efficiency of the antimicrobial action of the microemulsion. Microemulsions were formulated at different points within the microemulsion stability zone. Experiments were performed to observe the kinetics of killing of these microemulsions against selected test microorganisms (Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 10231, Staphylococcus aureus ATCC 6538 and Aspergillus niger ATCC 16404). The results indicated that the antimicrobial activity of the microemulsion is dependant upon its position within the zone of stability and is greater nearer the centre of that zone. The results indicate that significant antimicrobial activity can be observed at all points within the zone of microemulsion stability, but that maximal activity is to be found at the centre of that area

Physico-Chemical and Microbiological Studies on Jordanian Honey and Propolis as Potential Self-Preserving Pharmaceutical Systems

The aim of this project was to study the physico-chemical and antimicrobial properties of Jordanian honey and propolis in order to determine their potential as pharmaceutical preservation systems. This study undertook a physico-chemical analysis of several Jordanian honeys and one propolis type, in order to evaluate several physico-chemical properties including, pH and free acidity, moisture content, ash content and HydroxyMethylFurfural content in three honey samples, and total flavonoid content in the propolis sample. The antimicrobial activity of honey and propolis samples was then evaluated by determining the minimum inhibitory concentration (MIC) against Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 and Candida albicans ATCC 10231. Subsequently, Honey 1 (H1) was selected for further study and combined with propolis to test their potential synergistic activity. Finally, a preservative effectiveness test was conducted in order to assess the possibility of using honey and propolis as natural preservatives in aqueous dosage forms, such as syrups. The results of this study showed that all the tested honey samples and propolis possessed significant antimicrobial activity against the standard test microorganisms, and that honey with propolis exhibited synergistic activity that enhanced their antimicrobial activity and resulted in up to 90% reduction in their MIC values. This study also confirmed that honey and propolis could be used as a natural preservative system for pharmaceutical formulae. Our results reveal the possibility of using honey-propolis mixtures as natural preservatives in oral aqueous pharmaceutical dosage forms and other local application products

Does microbicide use in consumer products promote antimicrobial resistance? A critical review and recommendations for a cohesive approach to risk assessment

The increasing use of microbicides in consumer products is raising concerns related to enhanced microbicide resistance in bacteria and potential cross resistance to antibiotics. The recently published documents on this topic from the European Commission have spawned much interest to better understand the true extent of the putative links for the benefit of the manufacturers, regulators, and consumers alike. This white paper is based on a 2-day workshop (SEAC-Unilever, Bedford, United Kingdom; June 2012) in the fields of microbicide usage and resistance. It identifies gaps in our knowledge and also makes specific recommendations for harmonization of key terms and refinement/standardization of methods for testing microbicide resistance to better assess the impact and possible links with cross resistance to antibiotics. It also calls for a better cohesion in research in this field. Such information is crucial to developing any risk assessment framework on microbicide use notably in consumer products. The article also identifies key research questions where there are inadequate data, which, if addressed, could promote improved knowledge and understanding to assess any related risks for consumer and environmental safety

Probiotics versus Antibiotics: Is this the only option?

The role of probiotics in potential prophylaxis of infectious disease has been studied for over a century, but until recently there has been no real interest in using these ‘benign’ bacterial species in place of or in combination with antibiotics. However, such suggestions are now commonplace and lead to a renewed interest in what has until recently been seen as a merely commercial branch of microbiology. This short review looks at the current literature in this area and attempts to identify if there is a scientific basis to inform the cautious clinical use of probiotics either alone or in combination with antibiotics. Whilst the evidence base is to date rather thin, there is sufficient to allow for a cautious support for such ideas. This review also identifies those areas in which further study is required before the general use of probiotics in the treatment of infection may be fully supported

Efficient Design and Analysis of Lightweight Reinforced Core Sandwich and PRSEUS Structures

Design, analysis, and sizing methods for two novel structural panel concepts have been developed and incorporated into the HyperSizer Structural Sizing Software. Reinforced Core Sandwich (RCS) panels consist of a foam core with reinforcing composite webs connecting composite facesheets. Boeing s Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) panels use a pultruded unidirectional composite rod to provide axial stiffness along with integrated transverse frames and stitching. Both of these structural concepts are ovencured and have shown great promise applications in lightweight structures, but have suffered from the lack of efficient sizing capabilities similar to those that exist for honeycomb sandwich, foam sandwich, hat stiffened, and other, more traditional concepts. Now, with accurate design methods for RCS and PRSEUS panels available in HyperSizer, these concepts can be traded and used in designs as is done with the more traditional structural concepts. The methods developed to enable sizing of RCS and PRSEUS are outlined, as are results showing the validity and utility of the methods. Applications include several large NASA heavy lift launch vehicle structures

A review of the antimicrobial activity of thermodynamically stable microemulsions

Microemulsions are thermodynamically stable, transparent, isotropic mixtures of oil, water and surfactant (and sometimes a co-surfactant), which have shown potential for widespread application in disinfection and self-preservation. This is thought to be due to an innate antimicrobial effect. It is suggested that the antimicrobial nature of microemulsions is the result of a combination of their inherent kinetic energy and their containing surfactants, which are known to aid the disruption of bacterial membranes. This review examines the contemporary evidence in support of this theory.</p

Phosphorylation State-Dependent High Throughput Screening of the c-Met Kinase

High-throughput screening (HTS) of ~50,000 chemical compounds against phosphorylated and unphosphorylated c-Met, a tyrosine kinase receptor for hepatocyte growth factor (HGF), was carried out in order to compare hit rates, hit potencies and also to explore scaffolds that might serve as potential leads targeting only the unphosphorylated form of the enzyme. The hit rate and potency for the confirmed hit molecules were higher for the unphosphoryalted form of c-Met. While the target of small molecule inhibitor discovery efforts has traditionally been the phosphorylated form, there are now examples of small molecules that target unphosphorylated kinases. Screening for inhibitors of unphosphorylated kinases may represent a complementary approach for prioritizing chemical scaffolds for hit-to-lead follow ups

Water-in-oil microemulsions exhibit antimicrobial activity

Objectives: Previous research from this group has identified significant antimicrobial activity associated with oil-in-water (O/W) microemulsions. This activity has been exhibited against both bacteria and fungi (including yeasts) and bacterial biofilms and is dependent upon the position of the microemulsion within its stability zone. This novel work aims to identify antimicrobial activity of water-in-oil (W/O) microemulsions. Materials &amp; Methods: A simple, thermodynamically stable water-in-oil microemulsion was tested for its time-related antimicrobial activity against a selected panel of test microorganisms (i.e.: Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 8739, Candida albicans ATCC 10231 and Staphylococcus aureus ATCC 6538P) and its effectiveness as a self-preserving system against a similar panel (Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 10231, Staphylococcus aureus ATCC 6538P and Aspergillus niger ATCC 16404). Results: The microemulsion exhibited significant antimicrobial activity against all the selected microorganisms. Decreases in the viability of cultures (P. aeruginosa, C. albicans, E. coli and S. aureus) were observed over a short period of time after exposure to a known concentration of the first microemulsion. The results for the four samplings in the preservative effectiveness test according to the European Pharmacopeia requires a significant reduction in bacterial count, and this requirement was achieved in all samplings. Conclusions: Thermodynamically stable water-in-oil microemulsions are antimicrobially active, self-preserving systems, as are their oil-in-water counterparts

Strength in numbers : collaborative science for new experimental model systems

The work is made available under the Creative Commons CCO public domain dedication.. The definitive version was published in PLoS Biology 16 (2018): e2006333, doi:10.1371/journal.pbio.2006333.Our current understanding of biology is heavily based on a small number of genetically tractable model organisms. Most eukaryotic phyla lack such experimental models, and this limits our ability to explore the molecular mechanisms that ultimately define their biology, ecology, and diversity. In particular, marine protists suffer from a paucity of model organisms despite playing critical roles in global nutrient cycles, food webs, and climate. To address this deficit, an initiative was launched in 2015 to foster the development of ecologically and taxonomically diverse marine protist genetic models. The development of new models faces many barriers, some technical and others institutional, and this often discourages the risky, long-term effort that may be required. To lower these barriers and tackle the complexity of this effort, a highly collaborative community-based approach was taken. Herein, we describe this approach, the advances achieved, and the lessons learned by participants in this novel community-based model for research.The research efforts, connections, and collaborations described in this paper and protocols.io (https://www.protocols.io/) were supported by the Gordon and Betty Moore Foundation’s Marine Microbiology Initiative