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The 5th edition of Through the Microscope is now finished and available as a website subscription, as an ebook and as a hard copy from lulu.com. For subscribers to the 4th edition who are still using it, the book will stay available until May 15th, 2014. At that point, it will be retired. Thank you for all your support. For more information about the 5th edition, check out the latest news
Detecting pathogens in and on food is of great interest, especially considering the amount of ready to eat and processed food that is now consumed in the world. Recent Salmonella enterica and Haemorrhagic E. coli outbreaks have demonstrated the importance of testing food. One drawback to many current methods is that they rely on culturing the microbe from the food, with these procedures taking days to complete. Rapid methods for detecting pathogens are under development and Yamazaki et. al describe a new method, a loop-mediated isothermal amplification assay, for the detection of Vibrio parahaemolyticus. The assay takes 60 minutes or less to complete, in contrast to culturing methods that require several days.
Photorhabdous luminescens is a pathogen of certain important insects. What is more interesting from a science point of view, is that this microbe has a nematode partner. The nematode attacks the insect larvae and injects P. luminescens into it. The microbe then quickly kills the insect larvae and provides a ready meal for itself, with the nematode happily consuming the feast of microbes generated. In this report, Easom and Clarke demonstrate that while loss of motiliy does not seem to affect either symbiosis (with the insect or the nematode), a motility minus P. luminescens is less fit than wild-type for growth and in nature would be quickly out-competed by its motile brethren.
Predicting antibiotic resistance to novel anitmicrobials would be a neat trick. And with the use of bioinfomatics and the large collection of DNA that has been sequenced, it may be possible. Sanchez et. al. et. al demonstrate a proof of concept experiment. This is a clever, and novel approach and will hopefully better prepare medicine to predict and deal with drug resistance.
Francisella tularensis causes a nasty febrile infection that is highly contagious in humans . It is of intense interest because of its prevalence in the environment and its potential as a biological weapon. The natural reservoirs of the microbe and its prevalence are not fully understood, and a study by Zhang et. al. provides some insight into this. The microbe was found in two tick species, Dermacentor silvarum (sheep tick) and Ixodes persulatus, at a rate of 1.98 % in Northern China. So the microbe is reasonably common in the environment.
There is often a debate about what diseases were brought to the America's with the arrival of Europeans and what was was already there. It has been suggested that ulcers, caused by Helicobacter pylori, were also shared with the native population by conquering Europeans. A recent study by Castillo-Rojas et. al. decided to answer this question. Extracts taken from mummies were subject to PCR amplification looking for evidence of Helicobacter pylori. These mummies pre-date the arrival of the Conquistadors. If they are infected with the microbe, then it was already here and not brought in during the 15th century. They found that in fact, some of the mummies were infected and ulcers.