Metabolic engineering of the purine biosynthetic pathway in Corynebacterium glutamicum results in increased intracellular pool sizes of IMP and hypoxanthine

Background: Purine nucleotides exhibit various functions in cellular metabolism. Besides serving as building blocks for nucleic acid synthesis, they participate in signaling pathways and energy metabolism. Further, IMP and GMP represent industrially relevant biotechnological products used as flavor enhancing additives in food industry. Therefore, this work aimed towards the accumulation of IMP applying targeted genetic engineering of Corynebacterium glutamicum. Results: Blocking of the degrading reactions towards AMP and GMP lead to a 45-fold increased intracellular IMP pool of 22 mumol gCDW-1. Deletion of the pgi gene encoding glucose 6-phosphate isomerase in combination with the deactivated AMP and GMP generating reactions, however, resulted in significantly decreased IMP pools (13 mumol gCDW-1). Targeted metabolite profiling of the purine biosynthetic pathway further revealed a metabolite shift towards the formation of the corresponding nucleobase hypoxanthine (102 mumol gCDW-1) derived from IMP degradation. Conclusions: The purine biosynthetic pathway is strongly interconnected with various parts of the central metabolism and therefore tightly controlled. However, deleting degrading reactions from IMP to AMP and GMP significantly increased intracellular IMP levels. Due to the complexity of this pathway further degradation from IMP to the corresponding nucleobase drastically increased suggesting additional targets for future strain optimization

How Do Emergency Medical Service Workers Cope with Daily Stressors?

Emergency medical service (EMS) workers face triple the risk for significant mental health problems like depression and posttraumatic stress disorder (PTSD) compared to the general population. This brief summarizes the results of a study that surveyed EMS workers in Syracuse, NY to better understand how their mental health symptoms relate to daily occupational stressors. These stressors can take the form of routine work demands, critical incidents involving serious harm or death, and social conflicts. The study also examined whether daily mental health symptoms may be reduced through protective behaviors in the form of recovery activities such as exercising, socializing with other people, and finding meaning in the day’s challenges

Adsorption of Halogenated Fire-Extinguishing Agents on Powders

The amounts of four different Freons adsorbed by carbon, silica gel, alumina, and molecular sieves were determined at pressures up to 225 lb/sq in. The carbon adsorbed 50 to 100 percent and the silica gels, 30 to 50 percent of their own weight of Freon. Several adsorbed systems were tested in a standard dry-powder extinguisher on a 5-sq-ft gasoline fire for their effectiveness in putting out a fire. One of the Freons (bromotrifluoromethane) and carbon extinguished fires about as well as bicarbonate powder and nitrogen

Traits and conditions that accelerate teacher learning A consideration of the four-week Cambridge RSA Certificate in English Language Teaching to Adults

SIGLEAvailable from British Library Document Supply Centre-DSC:DX201563 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Plenary Speaker - What Keeps Teachers Going? What Keeps Teachers Developing?

What helps great teachers not just persevere but continue to be energized, fascinated and happily committed to teaching? These are the ones who keep going to conferences, take on leadership roles, keep reading new books on teaching, keep learning from other teachers - and from their students. What are their characteristics? And what are the implications for teacher education