It seems that the hype about viral pandemics is slowly decreasing while microbes and their functions are still the focus of many. Throughout the year 2022, researchers found many new bacterial species and genera, many of which might have benefits for us or help us tackle some of our environmental problems. Sarah Wettstadt highlights a few bacteria newly discovered in 2022 and what we can learn from them. #FascinatingMicrobes
New bacteria associated with plant and animal hosts
To improve animal feeding with more sustainable agricultural means, a study looked into the microbiota of sainfoin, a leguminous plant used in animal feeding due to its health benefits. They found two bacteria from the Rhizobiaceae family that induce nodules on the roots of legumes to fix atmospheric nitrogen.
The bacterium from the novel species Mesorhizobium onobrychidis actively promotes nodule formation on plant roots to build nitrogen-fixing symbioses. This nutrient exchange improves plant performance and supports plant development.
On the contrary, the bacterium Onobrychidicola muellerharveyae does not induce nodule formation but contains genes affiliated with motility, chemotaxis and host invasion. Interestingly, this bacterium from the new genus Onobrychidicola contains four gene copies of tabtoxin degradation enzymes. These likely aim to counterattack phytotoxins produced by plant pathogens and suggest that this bacterium might protect the host plant.
In another study, researchers shed light on the ecology of the mud crab Eurypanopeus depressus that lives along the North Carolina coastline in the USA. This crab is often infected with the parasite Loxothylacus panopaei which uses the crab as a vehicle for its own reproduction turning it into a “zombie-crab”.
Researchers now found that crabs infected with this parasite are often also infected with the pathogen Mellornella promiscua. This newly identified intracellular bacterium forms cellular vacuoles or plaques in the hepatopancreas of the host leading to its degradation.
Interestingly, Mellornella promiscua contains an abundance of sex-pili which gave it its name “promiscua”. So far, the ecological implication of the co-infection of the bacterium and the parasite is still unclear as well as its impact on the survival of the crabs.
New bacteria tackling environmental pollution
To tackle environmental pollution, scientists are constantly looking for microbial solutions. In the microbial bioremediation process, microorganisms degrade hazardous organic pollutants, like total petroleum hydrocarbon or pharmaceutical drugs.
Currently, the main known petroleum hydrocarbon degraders are bacteria, fungi and cyanobacteria, such as Pseudomonas, Acinetobacter, Flavobacterium and Corynebacterium. These often have a narrow activity spectrum or low degradation rates at physiologically relevant conditions.
In a contaminated oil field in Tianjin, China, researchers now isolated the petroleum degrader Falsochrobactrum tianjinense that has the highest sequence similarity to Falsochrobactrum shanghainese. The petroleum degradation rate of Falsochrobactrum tianjinense reached a level of 67.95% at 30 °C and at a pH of 7.0. Since this rate is more energy efficient than that of other degraders and the strain shows high adaptability to the environment, it has great potential for bioremediation applications in oil soils.
To identify potential drug-degraders, scientists investigated microbial biofilms from groundwater sources. They enriched samples on pharmaceuticals as sole carbon and energy sources and identified the strain Nocardioides carbamazepini. This Gram-positive and strictly aerobe bacterium showed an ibuprofen degradation rate of 70% after 7 weeks.
Interestingly, Nocardioides carbamazepini was also identified in samples enriched for carbamazepine but only reached a degradation rate of 4%. This implies that this strain might be involved in carbamazepine degradation but requires other microbial species for the full destruction of the molecule.
Welcome to the new bacteria in 2022
For the past three years, the whole world looked at certain virus strains and how to detect and inhibit them. In the meantime, researchers kept trying to identify new bacterial species with potential benefits.
While not all identified bacteria are always beneficial, finding new species helps researchers make sense of the bacterial world, the ecosystem and evolution. It doesn’t matter where the new bacteria from 2022 were found – be it on an Aluminium can from marine waste or the palm of a 67-year-old woman.
Every new bacterium can bring us one step closer to improving our lives or optimising biotechnological processes. It is up to microbiologists now to understand the new bacteria and find out how they might be able to help us.
Dr Sarah Wettstadt is a microbiologist-turned science writer and communicator writing for professional associations and life science organisations. She publishes the blog BacterialWorld to share the beauty of microbes and bacteria, is a content writer for QIAGEN and blog commissioner for the FEMSmicroBlog. Her overall vision is to empower through learning, which is why she founded SciComm Society to coach scientists in science communication. To spark interest in science at a younger age, Sarah coordinates workshops in schools for Native Scientist in Alicante. Previous to her science communication career, she did a PhD at Imperial College London, UK, and a postdoc at the CSIC in Granada, Spain. In her non-science time, Sarah enjoys the sunny beaches in Spain playing beach volleyball or travels the world.
About this blog section
The section #FascinatingMicrobes for the #FEMSmicroBlog explains the science behind a paper and highlights the significance and broader context of a recent finding. One of the main goals is to share the fascinating spectrum of microbes across all fields of microbiology.
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