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Climate change and the scarcity of primary resources are driving the development of new, more renewable and environmentally friendly industrial processes. As part of this green chemistry approach, extremozymes (extreme microbial enzymes) can be used to replace all or part of the chemical synthesis stages of traditional industrial processes. At present, the production of these enzymes is limited by the cellular chassis available. The production of a large number of extremozymes requires extremophilic cellular chassis, which are not available. This is particularly true of halophilic extremozymes. The aim of this review is to present the current potential and challenges associated with the development of a haloarchaea-based cellular chassis. By overcoming the major obstacle of the limited number of genetic tools, it will be possible to propose a robust cellular chassis for the production of functional halophilic enzymes that can participate in the industrial transition of many sectors. [ABSTRACT FROM AUTHOR]

Saline-alkaline lakes often shelter high biomasses despite challenging conditions, owing to the occurrence of highly adapted phototrophs. Dziani Dzaha (Mayotte) is one such lake characterized by the stable co-dominance of the cyanobacterium Limnospira platensis and the picoeukaryote Picocystis salinarum throughout its water column. Despite light penetrating only into the uppermost meter, the prevailing co-dominance of these species persists even in light- and oxygen-deprived zones. Here, a depth profile of phototrophs metatranscriptomes, annotated using genomic data from isolated strains, is employed to identify expression patterns of genes related to carbon processing pathways including photosynthesis, transporters and fermentation. The findings indicate a prominence of gene expression associated with photosynthesis, with a peak of expression around 1 m below the surface, although the light intensity is very low and only red and dark red wavelengths can reach it, given the very high turbidity linked to the high biomass of L. platensis. Experiments on strains confirmed that both species do grow under these wavelengths, at rates comparable to those obtained under white light. A decrease in the expression of photosynthesis-related genes was observed in L. platensis with increasing depth, whereas P. salinarum maintained a very high pool of psbA transcripts down to the deepest point as a possible adaptation against photodamage, in the absence and/or very low levels of expression of genes involved in protection. In the aphotic/anoxic zone, expression of genes involved in fermentation pathways suggests active metabolism of reserve or available dissolved carbon compounds. Overall, L. platensis seems to be adapted to the uppermost water layer, where it is probably maintained thanks to gas vesicles, as evidenced by high expression of the gvpA gene. In contrast, P. salinarum occurs at similar densities throughout the water column, with a peak in abundance and gene expression levels which suggests a better adaptation to lower light intensities. These slight differences may contribute to limited inter-specific competition, favoring stable co-dominance of these two phototrophs. [ABSTRACT FROM AUTHOR]

DNA ligase is an important enzyme ubiquitous in all three kingdoms of life that can ligate DNA strands, thus playing essential roles in DNA replication, repair and recombination in vivo. In vitro, DNA ligase is also used in biotechnological applications requiring in DNA manipulation, including molecular cloning, mutation detection, DNA assembly, DNA sequencing, and other aspects. Thermophilic and thermostable enzymes from hyperthermophiles that thrive in the hightemperature (above 80°C) environments have provided an important pool of useful enzymes as biotechnological reagents. Similar to other organisms, each hyperthermophile harbors at least one DNA ligase. In this review, we summarize recent progress on structural and biochemical properties of thermostable DNA ligases from hyperthermophiles, focusing on similarities and differences between DNA ligases from hyperthermophilic bacteria and archaea, and between these thermostable DNA ligases and non-thermostable homologs. Additionally, altered thermostable DNA ligases are discussed. Possessing improved fidelity or thermostability compared to the wild-type enzymes, they could be potential DNA ligases for biotechnology in the future. Importantly, we also describe current applications of thermostable DNA ligases from hyperthermophiles in biotechnology. [ABSTRACT FROM AUTHOR]

The article is an editorial that highlights various studies in extreme microbiology from the year 2023. The research topic focuses on desiccation-, heat-, and radiation-resistant bacteria, with additional studies on cell growth-inhibiting compounds, microbial cesium resistance, extreme pressure tolerance, and cold-adapted Antarctic sediment communities. The studies were contributed by research groups from China, Japan, Germany, Poland, the USA, and Korea, showcasing the geographical diversification of microbiological research. The article emphasizes the importance of understanding extremophilic microorganisms and their habitats, as they provide new research angles and surprises. [Extracted from the article]

Research has been conducted on the role of the Ti plasmid in the plant infection and colonization biology. Results indicate that Ti plasmid genes play direct or indirect roles in tumorigenesis or tumor colonization.

Organic-rich shales are populated by methanogenic consortia that are able to degrade the fossilized organic matter into methane gas. To identify the organic fraction effectively degraded, we have sequentially depleted two types of organic-rich sedimentary rocks, shale, and coal, at two different maturities, by successive solvent extractions to remove the most soluble fractions (maltenes and asphaltenes) and isolate kerogen. We show the ability of the consortia to produce methane from all rock samples, including those containing the most refractory organic matter, i.e., the kerogen. Shales yielded higher methane production than lignite and coal. Mature rocks yielded more methane than immature rocks. Surprisingly, the efficiency of the consortia was not influenced by the removal of the easily biodegradable fractions contained in the maltenes and asphaltenes. This suggests that one of the limitations of organic matter degradation in situ may be the accessibility to the carbon and energy source. Indeed, bitumen has a colloidal structure that may prevent the microbial consortia from reaching the asphaltenes in the bulk rock. Solvent extractions might favor the access to asphaltenes and kerogen by modifying the spatial organization of the molecules in the rock matrix. [ABSTRACT FROM AUTHOR]

Lipid membranes are essential cellular elements as they provide cellular integrity and selective permeability under a broad range of environmental settings upon cell growth. In particular, Archaea are commonly recognized for their tolerance to extreme conditions, which is now widely accepted to stem from the unique structure of their lipids. While enhancing the stability of the archaeal cell membrane, the exceptional properties of archaeal lipids also hinder their extraction using regular procedures initially developed for bacterial and eukaryotic lipids. The protocol described here circumvents these issues by directly hydrolyzing the polar head group(s) of archaeal lipids and extracting the resulting core lipids. Although leading to a loss of information on the nature of polar heads, this procedure allows the quantitative extraction of core lipids for most types of archaeal cells in an efficient, reproducible, and rapid manner., Competing Interests: Competing interestsThe authors declare no conflicts of interest., (Copyright © 2021 The Authors; exclusive licensee Bio-protocol LLC.)