Article
Biochemistry & Molecular Biology
Taylan Tunckanat, Aleksei Gendron, Zoie Sadler, Alex Neitz, Sarah Byquist, Thomas J. Lie, Kylie D. Allen
Summary: This study investigates the biosynthetic pathways of fi-lysine and fi-glutamate in Methanococcus maripaludis, revealing the importance of these fi-amino acids as osmolytes for survival in high salinity environments. The study characterizes two radical SAM aminomutases involved in the biosynthesis and expands the understanding of the diversity of radical SAM enzymes.
Article
Plant Sciences
Baber Ali, Xiukang Wang, Muhammad Hamzah Saleem, Aqsa Sumaira, Aqsa Hafeez, Muhammad Siddique Afridi, Shahid Khan, Antonio Teixeira do Zaib-Un-Nisa, Izhar Ullah, Antonio Teixeira do Amaral Junior, Aishah Alatawi, Shafaqat Ali
Summary: This study demonstrates that Enterobacter cloacae PM23 exhibits multi-stress tolerance and promotes plant growth under salinity stress. It mitigates salt stress by upregulating stress-related genes and producing beneficial substances. Inoculation with E. cloacae PM23 enhances plant adaptation to salinity stress, improving plant growth and antioxidant capacity.
Article
Microbiology
Zhengxin Dong, Tao Sun, Weiwen Zhang, Lei Chen
Summary: This article demonstrates the significant improvement of salt tolerance in Synechococcus elongatus PCC 7942 (Syn7942) by expressing the ectoine biosynthetic pathway. The engineered strain showed increased growth under high salt concentrations and could even survive under lethal levels of salt. Transcriptomic analysis revealed differences in the regulation of salt adaptation between the engineered strain and the wild-type, providing valuable insights for salt tolerance engineering in cyanobacteria.
FRONTIERS IN MICROBIOLOGY
(2023)
Article
Genetics & Heredity
Runting Ding, Na Yang, Jianguo Liu
Summary: This study reports the osmoadaptive mechanism of an extremely halophilic archaea, H. kocurii 2020YC7, isolated from a high salt environment. The strain utilizes various strategies including K+ uptake and output, trehalose production, and glycine betaine uptake to adapt to high salt conditions. Glycine betaine acts as the primary osmotic solute at high salt concentrations, while trehalose functions as an osmotic solute at lower salt concentrations.
Article
Environmental Sciences
Fengtian Yang, Dong Li, Xuejun Zhou, Tao Zhan, Yongfa Ma, Xu Wang, Junling Dong, Ling Liu, Yujia Shi, Yujuan Su
Summary: Geothermal systems provide unique habitats for extremophiles, and studying microbial communities is crucial for understanding the geochemical environment and fluid evolution in geothermal reservoirs. This study analyzed the microbial community structure and diversity in the sandstone reservoir of the Lindian geothermal field. The results revealed a high richness of microbial communities, which differed from other geothermal systems but resembled those found in oilfields.
Article
Ecology
Xiangxin Sun, Jun Zhao, Xue Zhou, Qicheng Bei, Weiwei Xia, Bingzi Zhao, Jiabao Zhang, Zhongjun Jia
Summary: This study investigated the composition and genomic adaptations of active ammonia oxidizers in a saline-sodic soil with high salinity and pH, revealing strong nitrification activities from both AOA and AOB. The dominant ammonia oxidizers in the solonetz soil were identified as members of the Nitrosococcus, while the farmland soil had dominant members of the Nitrosospira. Genomic analysis showed unique adaptations in Candidatus Nitrosococcus sp. Sol14 to facilitate osmotic and pH homeostasis in extreme habitats with excessive Na+ content. Salt-tolerance mechanisms were identified as the main driver for niche differentiation of ammonia oxidizers in saline-sodic soils.
Article
Microbiology
Gordon Webster, Barry A. Cragg, Joachim Rinna, Andrew J. Watkins, Henrik Sass, Andrew J. Weightman, R. John Parkes
Summary: This study analyzed the microbial diversity, geochemistry, and methanogenic activity of mud volcanoes in the Gulf of Cadiz. The results showed variable prokaryotic populations and activities, influenced by the geochemical heterogeneity of the sediments. Methane production from methyl compounds was higher than from other substrates, and only methylotrophic methanogenesis was observed in all the analyzed mud volcanoes. Further research is needed to determine the full contribution of these mud volcanoes to the global methane and carbon cycles.
FRONTIERS IN MICROBIOLOGY
(2023)
Article
Biochemistry & Molecular Biology
Davide Arella, Maddalena Dilucca, Andrea Giansanti
Summary: This study investigated the relationship between codon usage bias, microbial lifestyles, and habitats in 615 microbial organisms. The results showed that species with similar phenotypic traits living in similar environmental conditions exhibit similar codon preferences and tRNA availability. Additionally, organisms able to live in multiple habitats have reduced translational efficiency.
MOLECULAR GENETICS AND GENOMICS
(2021)
Article
Limnology
Sebastian Euler, Luke C. Jeffrey, Damien T. Maher, Scott G. Johnston, Ryo Sugimoto, Douglas R. Tait
Summary: Mangroves are important ecosystems that have significant impacts on primary production, carbon sequestration, and greenhouse gas cycles in coastal sediments. Microorganisms, specifically bacteria and archaea, play key roles in these processes. However, there are uncertainties regarding the functional and spatial distributions of microorganisms in mangroves.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Microbiology
Johannes F. Imhoff, Tanja Rahn, Sven Kunzel, Alexander Keller, Sven C. Neulinger
Summary: Osmotic adaptation and accumulation of compatible solutes are crucial processes for survival at high osmotic pressure and elevated salt concentrations. Glycine betaine and ectoine are the most important solutes that protect cell structures and metabolic processes at high salt concentrations, commonly found in marine and halophilic phototrophic bacteria with successful toleration of extreme salt concentrations. Transport systems for osmolytes are present in the studied bacteria.
Article
Food Science & Technology
Shamim Ahmed, Tae-Young Heona, Aritra Roy Choudhury, Denver Walitang, Jeongyun ChoinAff, Tongmin Sa
Summary: Soil salinization has a negative impact on crop yields, especially rice paddies, while salt stress can hinder plant growth by inducing physiological stresses. However, the accumulation of proline and glycine betaine can help improve plant growth under salt stress conditions.
APPLIED BIOLOGICAL CHEMISTRY
(2021)
Review
Biotechnology & Applied Microbiology
Stanislav Obruca, Pavel Dvorak, Petr Sedlacek, Martin Koller, Karel Sedlar, Iva Pernicova, David Safranek
Summary: This review summarizes the current knowledge on PHA accumulation in halophiles and thermophiles, highlighting the advantages of utilizing extremophiles for PHA production. It also discusses recent advances and future perspectives in metabolic engineering and synthetic biology for improving PHA production. The findings and ideas presented in this review suggest that biotechnological production of PHA by extremophiles can be sustainable and economically feasible, enabling PHA to compete with non-biodegradable petrochemical polymers in the market.
BIOTECHNOLOGY ADVANCES
(2022)
Article
Ecology
A. E. Bernhard, J. Beltz, A. E. Giblin, B. J. Roberts
Summary: This study found that potential nitrification rates in GoM marshes were more than 80 times higher than in NE salt marshes, with differences in abundances of AOA, comammox bacteria, and AOB between the two regions. The ratios of nitrifiers to total bacteria in NE were up to 80 times higher than in GoM, indicating differences in the relative importance of nitrifiers between the two systems.
ISME COMMUNICATIONS
(2021)
Article
Biochemistry & Molecular Biology
Amaravadhi Harikishore, Wuan-Geok Saw, Priya Ragunathan, Dennis Litty, Thomas Dick, Volker Mueller, Gerhard Gruber
Summary: This study elucidated the differences in the amino acid composition and structural features of the mycobacterial F-ATP synthase compared to other counterparts, paving the way for discovering molecules that can interfere with the regulative mechanisms of this essential energy converter. The essentiality of the mycobacterial peripheral stalk subunit delta for effective catalysis was demonstrated, leading to the identification of a potent subunit delta inhibitor. Targeting the delta subunit shows potential for developing F-ATP synthase inhibitors.
ACS CHEMICAL BIOLOGY
(2022)
Article
Biotechnology & Applied Microbiology
Nilanjan Pal Chowdhury, Dennis Litty, Volker Mueller
Summary: Acetobacterium woodii is an acetogen that can utilize methanol to produce acetate, making it a potential candidate for the production of bio-commodities. In this study, researchers introduced a butyrate production operon from a related acetogen into A. woodii, enabling stable production of butyrate from methanol. The addition of electrons in the form of carbon monoxide further enhanced butyrate production by recombinant A. woodii strains, expanding its product spectrum.
INTERNATIONAL MICROBIOLOGY
(2022)
Article
Microbiology
Dennis Litty, Florian Kremp, Volker Mueller
Summary: Acetogenic bacteria such as Acetobacterium woodii utilize the Wood-Ljungdahl pathway for CO2 fixation and energy conservation, converting methyl group containing substrates to acetate. Different pathways for the conversion of methyl-group containing substrates enable acetogens to adapt to various ecological niches and syntrophic communities.
ENVIRONMENTAL MICROBIOLOGY
(2022)
Article
Microbiology
Florian P. Rosenbaum, Anja Poehlein, Rolf Daniel, Volker Mueller
Summary: M. thermoacetica is capable of using dimethyl sulfoxide (DMSO) as an electron acceptor, which promotes its growth on glucose or H-2 + CO2. DMSO reductase activity was observed in the membranes of M. thermoacetica, with the enzyme exhibiting high activity at pH 5 and 60 degrees C. The study also identified potential DMSO reductase subunits and discussed their function and the proposed electron transport chain involving DMSO as the final electron acceptor.
ENVIRONMENTAL MICROBIOLOGY
(2022)
Article
Microbiology
Josephine Joy Hubloher, Lisa van der Sande, Volker Mueller
Summary: This study focused on the importance of Na+ homeostasis in Acinetobacter baumannii. Inactivation of the Mrp antiporter resulted in increased sensitivity to pH, Na+, and Li+, as well as energetic defects and impaired motility and survival under anoxic and dry conditions.
ENVIRONMENTAL MICROBIOLOGY
(2022)
Article
Microbiology
Raphael Trischler, Jennifer Roth, Matthew T. Sorbara, Xenia Schlegel, Volker Mueller
Summary: Species of the genus Blautia are beneficial gut microbes but their role in the gut microbiome and metabolic features are poorly understood. This study found that two relatives, Blautia luti and Blautia wexlerae, cannot grow on H-2 + CO2, but can perform acetogenesis through HCOOH + CO2 + CO. The lack of formate dehydrogenase and hydrogenase genes suggests that formate may be a more common interspecies carrier in the gut microbiome.
ENVIRONMENTAL MICROBIOLOGY
(2022)
Article
Multidisciplinary Sciences
Heng-Keat Tam, Patricia Konig, Stephanie Himpich, Ngoc Dinh Ngu, Rupert Abele, Volker Muller, Klaas M. Pos
Summary: This study reports the structural characteristics of AbMtlD and its role and mechanism in mannitol production. Salt-induced dimerization of AbMtlD increases its catalytic efficiency, resulting in unidirectional catalysis of mannitol production. These findings are important for understanding the survival mechanism of A. baumannii in low water activity environments.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Biochemistry & Molecular Biology
Alexander Katsyv, Volker Mueller
Summary: In this study, it was demonstrated that the energy-converting hydrogenase can reduce protons to produce molecular H-2 by translocating protons across the cell membrane. The purified enzyme showed full retention of its subunits and physiological activities.
JOURNAL OF BIOLOGICAL CHEMISTRY
(2022)
Article
Multidisciplinary Sciences
Helge M. Dietrich, Ricardo D. Righetto, Anuj Kumar, Wojciech Wietrzynski, Raphael Trischler, Sandra K. Schuller, Jonathan Wagner, Fabian M. Schwarz, Benjamin D. Engel, Volker Mueller, Jan M. Schuller
Summary: The structure of a filamentous enzyme, which has the potential to efficiently convert hydrogen and carbon dioxide into formic acid, has been revealed. This enzyme has gained interest in hydrogen storage and capturing atmospheric CO2 for combating climate change. The study shows that filamentation and rapid electron transfer enhance the activity of the enzyme. Additionally, cryo-electron tomography reveals the supramolecular organization of the enzyme in cells, which may further enhance its stability and connectivity. These findings provide insights into the function and applications of filamentous enzymes.
Article
Biology
Kanwal Kayastha, Alexander Katsyv, Christina Himmrich, Sonja Welsch, Jan M. Schuller, Ulrich Ermler, Volker Mueller
Summary: Lactate oxidation is an energetically demanding process, but some anaerobic bacteria use flavin-based electron bifurcation/confurcation (FBEB/FBEC) to overcome this energetic hurdle. The (Ldh-EtfAB)2 complex of Acetobacterium woodii, characterized by cryo-microscopy, reveals a mobile EtfAB shuttle domain between the rigid Ldh and peripheral EtfAB base units. The FADs of Ldh and the EtfAB shuttle domain interact to form the D state, while a plausible B state allows electron transfer between the EtfAB base and shuttle FADs. NAD(+) binding site correlates with the D-to-B-state transition, and kinetic analysis suggests a rotation of the EtfAB shuttle domain. Truncation of the ferredoxin domain of EtfA results in FBEC inactivity, supporting its role as a redox relay. A comprehensive catalytic mechanism of the FBEC process is proposed based on the catalytic base His423 and a metal center in Ldh.
Article
Microbiology
Florian Kremp, Jennifer Roth, Volker Mueller
Summary: Acetogenic bacteria utilize molecular hydrogen as an electron donor to convert CO2 into acetate, and a cytochrome-containing electron transport chain is involved in energy conservation. This represents a third way of chemiosmotic energy conservation in acetogens, in addition to the well-known respiratory enzymes Rnf and Ech.
MICROBIOLOGY SPECTRUM
(2022)
Article
Biochemistry & Molecular Biology
Alexander Katsyv, Melanie Essig, Giada Bedendi, Selmihan Sahin, Ross D. Milton, Volker Mueller
Summary: A study found that ferredoxin plays a major role in energy and carbon metabolism in the acetogenic model organism Thermoanaerobacter kivui. The researchers cloned and purified four putative ferredoxin-like proteins, and confirmed TKV_c09620 and TKV_c16450 as ferredoxins involved in autotrophic and heterotrophic metabolism of T. kivui.
Article
Ecology
Jimyung Moon, Anja Schubert, Lara M. Waschinger, Volker Mueller
Summary: Methyl groups in anoxic environments can be used as carbon and energy sources by microorganisms through oxidation to CO2 and electron transfer to an acceptor. This study describes the generation of a mutant acetogen that stops methyl group oxidation at the formate level and reoxidizes reduced electron carriers by CO2 reduction to acetate. The mutant can grow on glycine betaine as a methyl group donor and produce formate alongside acetate. This genetic reprogramming of an acetogen into a formatogen has implications for both biotechnology and the mechanism of electron transfer in anoxic environments.
Article
Chemistry, Multidisciplinary
Alexander. Katsyv, Anuj Kumar, Patricia Saura, Maximilian C. Poverlein, Sven A. Freibert, Sven T. Stripp, Surbhi Jain, Ana P. Gamiz-Hernandez, Ville R. I. Kaila, Volker Mueller, Jan M. Schuller
Summary: Electron bifurcation is a fundamental energy coupling mechanism used by microorganisms in anoxic conditions to reduce CO2 using hydrogen. The enzyme responsible for these reactions, HydABC, uses a single flavin mononucleotide (FMN) cofactor to transfer electrons to NAD(P)+ and low-potential ferredoxins (Fd), and switches between NAD(P)+ reduction and Fd reduction modes. Understanding the mechanistic principles of electron-bifurcating hydrogenases can provide insight into energy conversion processes in microorganisms.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Biotechnology & Applied Microbiology
Josephine Joy Hubloher, Lisa Van der Sande, Christoph Schaudinn, Volker Mueller, Beate Averhoff
Summary: Acinetobacter baumannii is a multidrug-resistant opportunistic pathogen that poses a significant threat to healthcare institutions. The Tol-Pal system plays a crucial role in cell morphology, antibiotic resistance, and virulence of A. baumannii.
INTERNATIONAL MICROBIOLOGY
(2023)
