In-depth analysis of amino acid and nucleotide sequences of Hsp60: How conserved is this protein?

Chaperonin Hsp60, as a protein found in all organisms, is of great interest in medicine, since it is present in many tissues and can be used both as a drug and as an object of targeted therapy. Hence, Hsp60 deserves a fundamental comparative analysis to assess its evolutionary characteristics. It was found that the percent identity of Hsp60 amino acid sequences both within and between phyla was not high enough to identify Hsp60s as highly conserved proteins. However, their ATP binding sites are largely conserved. The amino acid composition of Hsp60s remained relatively constant. At the same time, the analysis of the nucleotide sequences showed that GC content in the Hsp60 genes was comparable to or greater than the genomic values, which may indicate a high resistance to mutations due to tight control of the nucleotide composition by DNA repair systems. Natural selection plays a dominant role in the evolution of Hsp60 genes. The degree of mutational pressure affecting the Hsp60 genes is quite low, and its direction does not depend on taxonomy. Interestingly, for the Hsp60 genes from Chordata, Arthropoda, and Proteobacteria the exact direction of mutational pressure could not be determined. However, upon further division into classes, it was found that the direction of the mutational pressure for Hsp60 genes from Fish differs from that for other chordates. The direction of the mutational pressure affects the synonymous codon usage bias. The number of high and low represented codons increases with increasing GC content, which can improve codon usage. Special server has been created for bioinformatics analysis of Hsp60: http://oka.protres.ru:4202/.

Laboratory scale bioreactor designs in the processes of methane bioconversion: Mini-review.

Global methane emissions have been steadily increasing over the past few decades, exerting a negative effect on the environment. Biogas from landfills and sewage treatment plants is the main anthropogenic source of methane. This makes methane bioconversion one of the priority areas of biotechnology. This process involves the production of biochemical compounds from non-food sources through microbiological synthesis. Methanotrophic bacteria are a promising tool for methane bioconversion due to their ability to use this greenhouse gas and to produce protein-rich biomass, as well as a broad range of useful organic compounds. Currently, methane is used not only to produce biomass and chemical compounds, but also to increase the efficiency of water and solid waste treatment. However, the use of gaseous substrates in biotechnological processes is associated with some difficulties. The low solubility of methane in water is one of the major problems. Different approaches have been involved to encounter these challenges, including different bioreactor and gas distribution designs, solid carriers and bulk sorbents, as well as varying air/oxygen supply, the ratio of volumetric flow rate of gas mixture to its consumption rate, etc. The aim of this review was to summarize the current data on different bioreactor designs and the aspects of their applications for methane bioconversion and wastewater treatment. The bioreactors used in these processes must meet a number of requirements such as low methane emission, improved gas exchange surface, and controlled substrate supply to the reaction zone.