Lactobacillus hilgardii LMG 7934 genome deciphered at Kazan Federal University

If genetically “reprogrammed” to consume more nitrates, the bacteria can help in remediating environmental pollution.

The team is led by Associate Professor Ayrat Kayumov (Department of Genetics, Kazan Federal University). In this research, the scientists not only performed genome sequencing, but also found a completely new type of PII-Like Protein PotN.

“PII proteins can be called molecular processors,” explains Kayumov. “They monitor the ratios of metabolites in a cell which signal the availability of energy, carbon and nitrogen sufficiency, and, depending on this data, they can rearrange the cell functioning. We found a new type of PII-like proteins in this Lactobacillus hilgardii LMG 7934, and it has different functions. We now have to understand which signals trigger the activity of this type of proteins and how cell metabolism is coordinated as a result.”

The research is funded by the Presidential Grant Program of Russia for Young Scientists with DSc degrees.

“Our projects aims to characterize molecular mechanisms which allow bacteria to use nitrogen-containing compounds. This can help correct the bacterial metabolism in such a way that it could work in a targeted direction, such as nitrate consumption,” continues the interviewee.

For instance, this may come in handy for biological purification and remediation of polluted water sources or to ensilage livestock feed with high nitrate ratios. Excessive nitrates in food can be detrimental to animals.

“Nitrates amass in plants when nitrogen-containing fertilizers are used. These nitrates transform into nitrites during storage or directly in animal gut. Nitrites turn blood hemoglobin into methemoglobin, which leads to oxygen deficiency, including acute forms,” says Kayumov. “During ensilaging, gases are produced, and fresh silage is very poisonous. Silage gases contain molecular oxygen, nitrous oxide, nitrous dioxide, and nitric oxide. During ensilaging, nitrates can also be reduced to ammonium. That’s why it’s important to abide by technological norms to decrease the ratio of nitrates in feed. However, if source plants have over 0.28% of nitrates, ensilaging cannot effectively reduce their ratio.”

That’s why geneticists aim to produce special ferments for feed ensilaging based on lactobacilli – the latter can help remove nitrates. Targeted genetic modification is a way to achieve exactly that.

Complete Genome Sequence of Lactobacillus hilgardii LMG 7934, Carrying the Gene Encoding for the Novel PII-Like Protein PotN

https://link.springer.com/article/10.1007/s00284-020-02161-6

Source text: Larisa Busil

Translation: Yury Nurmeev