A loop-mediated isothermal amplification (LAMP) assay for open reading frame 1 (ORF1) of the glutamine synthetase gene of Neisseria gonorrhoeae was able to tolerate urea concentrations of ≤1.8 M, compared with a PCR assay that was functional at concentrations of <100 mM. The LAMP assay was as sensitive as the PCR assay while being faster and simpler to perform.

This paper explores the use of low-frequency-low-amplitude acoustic vibration on biofilm formation. Biofilm development is thought to be governed by a diverse range of environmental signals and much effort has gone into researching the effects of environmental factors including; nutrient availability, pH and temperature on the growth of biofilms. Many biofilm-forming organisms have evolved to thrive in mechanically challenging environments, for example soil yet, the effects of the physical environment on biofilm formation has been largely ignored. Exposure of Pseudomonas aeruginosa to vibration at 100, 800 and 1600 Hz for 48 h, resulted in a significant increase in biofilm formation compared with the control, with the greatest growth seen at 800 Hz vibration. The results also show that this increase in biofilm formation is accompanied with an increase in P. aeruginosa cell number. Acoustic vibration was also found to regulate the spatial distribution of biofilm formation in a frequency-dependent manner. Exposure of Staphylococcus aureus to acoustic vibration also resulted in enhanced biofilm formation with the greatest level of biofilm being formed following 48 h exposure at 1600 Hz. These results show that acoustic vibration can be used to control biofilm formation and therefore presents a novel and potentially cost effective means to manipulate the development and yield of biofilms in a range of important industrial and medical processes.

Aims: This study was conducted to investigate the application of 2,2′-dipyridyl as a new approach to isolating siderophore-producing actinobacteria. Methods and Results: Isolation of actinobacteria from soil was conducted by a soil dilution plate technique using starch-casein agar. Iron starvation was fostered by the incorporation of the iron chelator 2,2′-dipyridyl in the isolation medium. Pretreatment of the samples at an elevated temperature (40°C) ensured that the majority of nonsporulating bacteria were excluded. The survivors of this treatment were largely actinobacteria. Of the viable cultures grown in the presence of 2,2′-dipyridyl, more than 78–88% (average of three separate studies) were reported to produce siderophore-like compounds compared to 13–18% (average of three separate studies) when grown on the basic media in the absence of the chelating agent. The most prolific producers as assessed by the chrome azurol sulphate (CAS) assay were further characterized and found to belong to the genus Streptomyces. Conclusions: Selective pressure using 2,2′-dipyridyl as an iron-chelating agent in starch-casein media increased the isolation of siderophore-producing actinobacteria compared to the unamended medium. Significance and Impact of the Study: The study described represents a new approach to the isolation of siderophore-producing actinobacteria using a novel procedure that places a selection on cell population based upon the incorporation of a chelating agent in the medium.