Metalloid tellurium is characterized as a chemical element belonging to the chalcogen group without known biological function. However, its compounds, especially the oxyanions, exert numerous negative effects on both prokaryotic and eukaryotic organisms. Recent evidence suggests that increasing environmental pollution with tellurium has a causal link to autoimmune, neurodegenerative and oncological diseases. In this review, we provide an overview about the current knowledge on the mechanisms of tellurium compounds’ toxicity in bacteria and humans and we summarise the various ways organisms cope and detoxify these compounds. Over the last decades, several gene clusters conferring resistance to tellurium compounds have been identified in a variety of bacterial species and strains. These genetic determinants exhibit great genetic and functional diversity. Besides the existence of specific resistance mechanisms, tellurium and its toxic compounds interact with molecular systems, mediating general detoxification and mitigation of oxidative stress. We also discuss the similarity of tellurium and selenium biochemistry and the impact of their compounds on humans.

Vibrio natriegens is a fast-growing, non-pathogenic marine bacterium with promising features for biotechnological applications such as high-level recombinant protein production or fast DNA propagation. A remarkable short generation time (< 10 min), robust proteosynthetic activity and versatile metabolism with abilities to utilise wide range of substrates contribute to its establishment as a future industrial platform for fermentation processes operating with high productivity.D,D-carboxypeptidases are membrane-associated enzymes involved in peptidoglycan biosynthesis and cell wall formation. This study investigates the impact of overexpressed D,D-carboxypeptidases on membrane integrity and the increased leakage of intracellular proteins into the growth medium in V. natriegens. Our findings confirm that co-expression of these enzymes can enhance membrane permeability, thereby facilitating the transport of target proteins into the extracellular environment, without the need for secretion signals, tags, or additional permeabilization methods. Using only a single step IMAC chromatography, we were able to purify AfKatG, MDBP or Taq polymerase in total yields of 117.9 ± 56.0 mg/L, 36.5 ± 12.9 mg/L and 26.5 ± 6.0 mg/L directly from growth medium, respectively. These results demonstrate the feasibility of our V. natriegens based system as a broadly applicable extracellular tag-less recombinant protein producer.

DNA amplification and reverse transcription enzymes have proven to be invaluable in fast and reliable diagnostics and research applications because of their processivity, specificity, and robustness. Our study focused on the production of mutant Taq DNA polymerase and mutant M-MLV reverse transcriptase in the expression hosts Vibrio natriegens and Escherichia coli under various expression conditions. We also examined nonspecific extracellular production in V. natriegens. Intracellularly, M-MLV was produced in V. natriegens at the level of 11% of the total cell proteins (TCPs) compared with 16% of TCPs in E. coli. We obtained a soluble protein that accounted for 11% of the enzyme produced in V. natriegens and 22% of the enzyme produced in E. coli. Taq pol was produced intracellularly in V. natriegens at the level of 30% of TCPs compared with 26% of TCPs in E. coli. However, Taq pol was almost non-soluble in E. coli, whereas in V. natriegens, we obtained a soluble protein that accounted for 23% of the produced enzyme. We detected substantial extracellular production of Taq pol. Thus, V. natriegens is a suitable alternative host with the potential for production of recombinant proteins.