Microbe Talk: November 2014

521724789New York’s Central Park is huge. This iconic rectangle of greenery, 2.5 miles long and 0.5 miles wide, receives 40 million human visitors annually and is home to hundreds of species of animals and insects, and over 25,000 trees. But what of the world beneath the soil? How many microbes are living beneath the different environments found in the park?

A recent paper, published in Proceedings of the Royal Society B, has investigated the below-ground microbial diversity in Central Park. We spoke to Dr Kelly Ramirez, the study’s lead author, who is currently working as a Postdoctoral Researcher at the Netherlands Institute of Ecology. Kelly told us how she went about searching for microbes in the park, and how many new species were uncovered.

Show notes:

Don’t forget, you can subscribe to Microbe Talk on iTunes. You can also find us on Stitcher.

Benjamin Thompson

Image Credit: Thinkstock
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Not to be underestimated: nematodes learn to avoid smelly bacteria

C elegans

C. elegans nematodes (black) on a background of E. coli.

There are many examples of remarkable intelligence from the animal kingdom: chimpanzees can learn sign language and use tools to gather food; elephants have been known to perform basic maths; and a Border Collie named Chaser knows over 1,000 different toys by name. These remarkable feats are generally associated with mammals; more primitive organisms are rarely considered to be particularly intelligent.

However, this is unjustified – take Caenorhabditis elegans, for example. This nematode (or roundworm) consists of only about 1,000 cells and has no brain, although nearly a third of the cells in its body are neurons responsible for transmitting information around the body. Despite its very simple anatomy, researchers at Rockefeller University in New York found that C. elegans is capable of “learning” which chemical signals are associated with harmful bacteria. They believe that the nematodes’ ability to learn is associated with their olfactory neurons – that is, their sense of smell.

C. elegans usually lives in soil, an environment abundant in bacteria; some, such as Escherichia coli, are a food source for the nematodes, while others are harmful to them. To study the nematodes’ ability to learn from experiences, the scientists looked at how ‘naive’ nematodes – raised without exposure to harmful bacteria – responded to a choice between moving towards edible E. coli or towards pathogens. Having not had the opportunity to learn that pathogens are harmful and not a source of food, roughly equal numbers of these nematodes moved towards the pathogens and towards the E. coli. Repeating the experiment with nematodes that had previously been exposed to pathogens, the researchers found that almost all of them avoided the pathogens and moved towards the safe food source. These results suggest that odour recognition is not instinctive, but can be learned through exposure to harmful bacteria.

The learning ability of C. elegans is now being used to evaluate the pathogenicity of different bacterial strains. Euan Scott, a PhD student at the University of Southampton, is using the nematodes to model how likely the various bacteria are to cause infection and disease in humans. He is presenting his work at the Society for General Microbiology’s Focused Meeting in London today.

Scott uses laboratory-grown, naive nematodes and places them near E. coli patches laced with harmful bacteria. Rather than having to choose between pathogens and safe food, the nematodes now have to learn that their food contains harmful substances. The theory underlying his experiments is that more dangerous bacteria elicit stronger aversive reactions in C. elegans, meaning that more of them will learn to abandon the food patch in search of alternative food sources. Scott is also investigating how the nematodes’ fertility changes when they spend time near pathogens. If the number of eggs were to be directly related to exposure to harmful bacteria, this would be useful for determining the pathogenicity of bacteria.

Knowing how harmful different strains of bacteria are – and which genes cause their pathogenicity – will hopefully translate into human medicine and inform future antibacterial drugs and treatment methods.

The other important aspect of Scott’s research is that while we know which neurons are activated in C. elegans in response to odours, it is not clearly understood how exactly the learning process takes place. He thinks that decoding the learning process of nematodes could mark an important step in understanding how more complex organisms such as humans form memories.

Euan Scott’s work on nematode-based pathogenicity models is just one of many cutting-edge research projects showcased at the Society for General Microbiology’s Focused Meeting in London. To stay up to date on our future events, visit our website.

Jon Fuhrmann

Image Source: Niharb on Flickr under CC BY-NC-ND 2.0.
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New to Science: November Edition

Wine: New to Science in MicrobiologyEach month, the Society for General Microbiology publishes the International Journal of Systematic and Evolutionary Microbiology, which details newly discovered species of bacteria, fungi and protists. Here are a few of the new species that have been discovered, and the places they’ve been found. The full papers are available to journal subscribersbut the abstracts are free to read.

As supermarkets and the media never fail to remind us, the festive season has arrived – whether we like it or not. Fortunately, this is also an opportunity to relax a little and enjoy quality time with those dear to us. More often than not, a sophisticated tipple is served at such social occasions – much to the joy of the wine industry.

French wine producers, in particular, are pleased with the outcome of the 2014 harvest and are predicting that this will have been a good wine year. Their Greek counterparts are less optimistic: difficult weather conditions throughout the growing and harvesting seasons saw production drop by 15%. A team of microbiologists from Greek universities also took an interest in their country’s wine output, albeit for a different reason. They studied grapes from a vineyard in the Nemea region and isolated a new species of bacterium, Weissella uvarum.

In other parts of the world, fermented grape juice is less of a staple at the dining-room table. Researchers at Chung-Ang University in Seoul studied a dish called myeolchi-jeot, a traditional Korean dish made from fermented anchovies, and identified the bacterium Salimicrobium jeotgali. Sugarcane juice, meanwhile, is a popular drink across Southeast Asia. A Thai team isolated Wickerhamiella siamensis, a species of yeast that grows on the leaves of sugarcane plants without damaging them.

Another species of Wickerhamiella bacteria, W. allomyrinae, was discovered in the gut of a rhinoceros beetle by Chinese scientists. Since these beetles feed on sugarcane plants, the bacterium was likely consumed by the specimen just before it was studied by the researchers.

Elsewhere in the animal kingdom, Japanese researchers isolated a previously unknown species of Streptococcus from the oral cavity of an African elephant. They named it S. oriloxodontae, after ‘oris’ (Greek for ‘mouth’) and ‘loxodontae’, the scientific name of the African elephant. Danish and German scientists studied Syrian and European hamsters and isolated two new genera of bacteria, both in the Pasteurellaceae family. They named them Mesocricetibacter intestinalis and Cricetibacter osteomyelitidis, respectively.

As they are wont to do, a number of microbiologists have also been travelling to far-flung places in pursuit of their quest to introduce hitherto unknown microbes to science. In Bijie in southern China, Thermomonas carbonis was isolated from soil inside a coal mine. A team from Korea scaled the country’s tallest mountain, Hallasan, to isolate Aneurinibacillus soli from a soil sample collected at 1,950m above sea level. A different group discovered Pedobacter pituitosus at the Wibong waterfalls, less than 200 miles to the north.

American and Korean researchers teamed up to explore the Juan de Fuca Ridge off the coasts of the northwestern USA and British Columbia in Canada. Here, they discovered Thermococcus paralvinellae and T. cleftensis, two heat-loving species of bacteria that thrive in the low-oxygen conditions of hydrothermal vents. Over 5,000 miles to the southwest, a Japanese team isolated Psychrobium conchae from the Iheya North hydrothermal field off the eponymous island in Okinawa, Japan.

To get our loyal readers into the spirit for next month’s Christmas edition, we conclude this issue of New to Science with a microbe that was discovered near the closest fully functional settlement to the North Pole. A group of scientists from Wuhan University in China discovered Terrimonas arctica in a sample of the frozen soil near Ny-Ålesund in the Svalbard archipelago.

These are just a few of the new species described this month; you can see the full list on the IJSEM website. We’ll be back again next month with a host of new ones  look out for us then!

Jon Fuhrmann

Image credit: Paul Lieberwirth on Flickr under CC BY-NC-ND 2.0.
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Can probiotics help treat antibiotic-related infection?

ResearchBlogging.orgYoghurtIf you go down to your local supermarket today, you shouldn’t be surprised if you find a wide array of probiotic-based products (mainly yoghurts), each associated with claims that they will improve your dietary health. Whether probiotics actually provide any specific health benefits remains hotly debated.

One area where probiotics do seem to make a difference is in preventing Antibiotic Associated Diarrhoea (AAD), which can be a serious problem, particularly in healthcare settings. A 2013 Cochrane review, which compared the results from 31 randomised trials, suggests that probiotics, when taken together with antibiotics, can reduce the risk of C. difficile-associated diarrhoea by 64%. Continue reading

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Hold tight: A mussel-inspired ‘living glue’

ResearchBlogging.orgMussel (Mytilus galloprovincialis) Adhesive Glue Many aquatic animals spend much of their lives stuck to surfaces that can include rocks, ships or even whales. Limpets and sea stars, for example, use a form of adhesion that allows them to move on the surface they have colonised, but which makes them very hard to remove from that surface. Barnacles and mussels, meanwhile, produce fully-fledged underwater glues, known as bioadhesives; once they attach to a surface, these animals spend the rest of their lives stationary. Researchers have been aware of the strength of these glues for some time, but attempts to create artificial substances that rival their underwater adhesive power have been largely unsuccessful – until now. Continue reading

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Microbe Talk: October 2014

Rasacee_couperose_zones.svgYou might not know it, but right now there are very likely to be microscopic mites living on your face. These mites are microscopic, so you won’t see them if you look in the mirror. For most of us, these mites are totally harmless and just live off the natural oils produced by our skin. However, they have also been implicated in the skin condition rosacea, which potentially affects as many as 1 in 10 people. We spoke to Fred McMahon, a PhD student at Maynooth University, about the mites and how the bacteria within them may be at the root of rosacea.

Show notes:

Don’t forget, you can subscribe to Microbe Talk on iTunes. You can also find us on Stitcher.

Benjamin Thompson

Image credit: Karl Udo on Wikimedia Commons, via Free Art License 1.3
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World Polio Day 2014

Polio Vaccination - World Polio Day 2014. Credit: UNICEF Ethiopia24 October is World Polio Day, an event that aims to raise awareness of the continuing threat of polio to children in some parts of the world. A global effort to eradicate the disease has been ongoing for 26 years, reducing the number of cases from over 350,000 in 1988 to 406 in 2013. Today, only three countries – Afghanistan, Pakistan and Nigeria – have yet to eradicate the virus. However, in 2014, new cases of polio have also been documented in Iraq, Syria, Cameroon, Equatorial Guinea, Somalia and Ethiopia – all countries that were previously polio-free. This reintroduction of the disease highlights that as long as a single person remains infected, polio can return. According to the World Health Organization, a renewed spread of polio could cause up to 200,000 new cases over the course of a decade and cost the global economy billions of dollars.

What is polio?
Polio is short for Poliomyelitis and is also known as infantile paralysis. It is an infectious disease caused by the three different types of poliovirus, which mainly infect children under 5 years of age. Polioviruses can live in an infected person’s faeces for several weeks and are transmitted mainly via the faecal-oral route, meaning that they can spread through water supplies and food in unsanitary conditions. Polio can also be spread through droplets from the sneezes and coughs of infected people. Continue reading

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