From cats to crustaceans: new microbes discovered this month
Posted on April 4, 2023 by Clare Baker
Each month, the Microbiology Society publishes the International Journal of Systematic and Evolutionary Microbiology, which details newly discovered species of bacteria, fungi and protists. Here are some of the new species that have been discovered and the places they've been found.
In this month’s New to Science, we start with microbes that have been discovered in animals. First, let’s head into the mouths of our close feline friends. In 2007 Japan, three strains of bacteria belonging to the genus Capnocytophaga were isolated from the oral cavity of cats. One of the strains has recently been identified as a new species, Capnocytophaga catalasegens. This new species lacks catalase activity, which sets it apart from all other known species in the genus that are found in the oral cavities of cats and dogs. It is this characteristic that gives C. catalasegens its name – ‘catalasum’, referring to the ‘catalase’ enzyme, and ‘egens’, meaning ‘lacking’.
The second animal to feature on this month’s whistle stop tour of microbes which are new to science is a known fan favourite, Apis melifera, or you might know it by its common name – the honeybee. Our new bacteria, Bifidobacterium mellis is found in the honey stomach of these bees. The honey stomach is part of the bee’s digestive tract and is used for the collection and transportation of nectar to the hive. It plays a key role in the production of honey and ‘bee bread’ – a pollen and honey mixture which acts as a source of food for worker bees and larvae. This new bacteria joins the genus Bifidobacterium, a symbiotic lactic acid bacteria present in all recognised honey bee species. Not only is this highly co-evolved genus important in bee food production, it also plays an important role in the bee immune systems.
The last on our list of animals where new microbes have been found is popular with humans, but perhaps not for the same reasons as cats and honey bees. When researchers were isolating bacteria from farmed shrimp, they discovered a new species in the intestinal tract of Litopenaeus vannamei – the tasty pacific white shrimp. This novel bacteria, Maribacter litopenaei, gets its name from this association.
And finally, we look to the wonderful environment around us for new microbes. This month saw the discovery of Brevibacillus humidisoli, a bacteria isolated from riverside soil in the Suncheon bay area in South Korea – an area close to a national garden harbouring a unique ecosystem. B. humidisoli, which gets its name from – you guessed it – humid soil, is moderately thermoalkaliphilic and halotolerant. This means that it can grow at moderately high temperatures, pH and salinity. B. humidisoli is a member of the genus Brevibacillus, which has been found in a variety of diverse habitats including soil, hot springs and the deep sea. Identifying members of this genus isn’t easy, as most strains show low levels of activity in biochemical and physiological tests.
The last stop on our tour of new microbes is the Amazon rainforest, where two new yeasts have been discovered. Four isolates of the Spathaspora species were recovered from rotting wood; two in the state of Pará and two in the state of Tocantins. They were named Spathaspora brunopereirae and Spathaspora domphillipsii to recognise the contributions of Bruno da Cunha Araújo Pereira and Dominic Mark Philips to the preservation of Amazonian ecosystems. Despite the Amazon representing 40% of the world’s remaining tropical forests and accounting for 10% of the planets known biodiversity, yeast biodiversity there is only beginning to be explored. Research is also largely restricted to the discovery of non-conventional yeasts used for bioethanol production. It is increasingly important that yeasts in the rainforest are documented as recent fires have had devastating consequences for the biodiversity across a significant area of the Brazilian Amazon.