Chris Greening | |
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Born | |
Occupation(s) | Biochemist, microbiologist, academic, journalist |
Awards | Discovery Early Career Researcher Award (DECRA) Fellowship, Australian Research Council (ARC) Emerging Leader 2 (EL2) Fellowship, National Health and Medical Research Council (NHMRC) Fellow (FASM), Australian Society for Microbiology Fenner Medal, Australian Academy of Science Life Scientist of the Year, Prime Minister's Prizes for Science |
Academic background | |
Alma mater | University of Oxford University of Otago |
Academic work | |
Institutions | Monash University |
Website | http://www.greeninglab.com |
Chris Greening is a biochemist,microbiologist,academic,and journalist. He is a Professor of Microbiology and leads the One Health Microbiology group and Global Change Research Program [1] of the Biomedicine Discovery Institute at Monash University in Melbourne,Australia. [2] He is most known for his work on the basis,role,and significance of the microbial metabolism of trace gases such as hydrogen,methane,carbon monoxide,and carbon dioxide. [3] [4] He has held prestigious fellowships from the CSIRO (2014-2016),Australian Research Council (2017-2019),and National Health and Medical Research Council (2020-2024) [5] and was awarded the Fenner Medal 2022 from the Australian Academy of Science. [6] Greening was awarded the Prime Minister's Prize for Life Scientist of the Year in 2023. [7]
Greening was born in a working-class family,and grew up in Wallasey,Clevedon,and Nailsea. He completed his secondary education at Nailsea School and received scholarships to attend St. Catherine’s College,University of Oxford. He graduated with a degree in Molecular and Cellular Biochemistry in 2010. [8] After emigrating to New Zealand,he earned his Ph.D. in Microbiology and Immunology from the University of Otago in 2014. [9] His dissertation,"Physiological roles of the three [NiFe]-hydrogenases in Mycobacterium smegmatis",was primarily supervised by Gregory Cook and was formally recognized as "exceptional". [10] [11]
Between 2002 to 2017,he served as a staff member for various video game music websites. While still studying at Nailsea School,he was the co-webmaster for SquareSound,a website dedicated to music from Square Enix games. [12] After SquareSound launched a store,he stepped down from the staff team and founded Square Enix Music Online in 2006,also featuring a particular focus on soundtracks from Square Enix games,but covering game music as a whole. This website featured a database of soundtracks,news articles,soundtrack reviews,interviews with composers,and composer biographies. It was succeeded by VGM Online in 2014,largely serving the same purpose. [13]
After receiving his doctorate,Greening gained postdoctoral and lecturing experience with short-term positions at the University of Otago,CSIRO,and Australian National University. In 2016,he established his research group at Monash University’s School of Biological Sciences and completed an environmentally-focused ARC DECRA Fellowship. [5] After being awarded a medically-focused NHMRC EL2 Fellowship, [14] he became an Associate Professor at Monash University’s Department of Microbiology in 2020 and was promoted to full Professor in 2022. [2] [15] He is the Environmental Microbiology advisor for the Australian Society for Microbiology, [16] and serves as an editor for the journals mSystems [17] and Microbial Genomics. [18]
Greening has studied the use of microbiology to address global challenges,including climate change,infectious disease,and food and water security. His group and collaborators integrate the fields of microbial biochemistry,physiology,genetics,ecology,biogeochemistry,and biotechnology. This depends on using techniques such as metagenomics,gas chromatography,cryo-electron microscopy,and CRISPR interference. [19]
Greening co-discovered that atmospheric trace gases are major energy sources for microorganisms. [20] He provided the first genetic proof that microorganisms mediate the major biogeochemical process of atmospheric hydrogen oxidation. Through microbial genetics and biochemistry,he identified the unique hydrogenase enzymes that mediate this process, [21] [22] demonstrated that they are important for long-term survival of dormant bacteria, [23] and resolved their structure and mechanism at atomic detail. [24] At the ecosystem scale,he has demonstrated that atmospheric trace gas oxidation is mediated by multiple bacterial and archaeal phyla, [25] and helps sustain biodiversity and productivity of terrestrial and aquatic ecosystems. [20] Notably,his team have revealed that some extreme environments such as Antarctic desert soils are driven primarily by atmospheric energy sources, [26] rather than photosynthesis. His work has also confirmed the basis and role of atmospheric carbon monoxide oxidation. [27]
Greening has also worked on methane emissions. He has revealed complex metabolic interactions between bacteria and archaea control methane emissions from a range of systems,including soils, [28] oceans, [29] livestock, [30] geothermal springs,hydrocarbon seeps, [31] tree stems, [32] and termite mounds. [33] Through this work,he has also identified novel methanotrophic bacteria that consume methane at elevated or atmospheric concentrations,including “Candidatus Methylotropicum kingii”from the phylum Gemmatimonadota.
Greening is also a chief investigator of several research programs,namely SAEF:Securing Antarctica’s Environmental Future, [34] RISE:Revitalising Informal Settlements and their Environments, [35] the ARC Research Hub for Carbon Utilisation and Recycling, [36] and the Centre to Impact Antimicrobial Resistance. For the RISE program,he developed quantitative PCR cards that enable rapid and sensitive detection of multiple bacterial,viral,protist,and helminth pathogens across any given human,animal,or environmental sample. [37] [38] In the medical space,he has identified new drug targets and antimicrobial resistance mechanisms for tuberculosis,for example by resolving the biosynthesis pathway of the coenzyme F420. [39] [40]
Anaerobic respiration is respiration using electron acceptors other than molecular oxygen (O2). Although oxygen is not the final electron acceptor,the process still uses a respiratory electron transport chain.
Methanogens are anaerobic archaea that produce methane as a byproduct of their energy metabolism,i.e.,catabolism. Methane production,or methanogenesis,is the only biochemical pathway for ATP generation in methanogens. All known methanogens belong exclusively to the domain Archaea,although some bacteria,plants,and animal cells are also known to produce methane. However,the biochemical pathway for methane production in these organisms differs from that in methanogens and does not contribute to ATP formation. Methanogens belong to various phyla within the domain Archaea. Previous studies placed all known methanogens into the superphylum Euryarchaeota. However,recent phylogenomic data have led to their reclassification into several different phyla. Methanogens are common in various anoxic environments,such as marine and freshwater sediments,wetlands,the digestive tracts of animals,wastewater treatment plants,rice paddy soil,and landfills. While some methanogens are extremophiles,such as Methanopyrus kandleri,which grows between 84 and 110°C,or Methanonatronarchaeum thermophilum,which grows at a pH range of 8.2 to 10.2 and a Na+ concentration of 3 to 4.8 M,most of the isolates are mesophilic and grow around neutral pH.
Methanogenesis or biomethanation is the formation of methane coupled to energy conservation by microbes known as methanogens. It is the fourth and final stage of anaerobic digestion. Organisms capable of producing methane for energy conservation have been identified only from the domain Archaea,a group phylogenetically distinct from both eukaryotes and bacteria,although many live in close association with anaerobic bacteria. The production of methane is an important and widespread form of microbial metabolism. In anoxic environments,it is the final step in the decomposition of biomass. Methanogenesis is responsible for significant amounts of natural gas accumulations,the remainder being thermogenic.
Microbial ecology is the ecology of microorganisms:their relationship with one another and with their environment. It concerns the three major domains of life—Eukaryota,Archaea,and Bacteria—as well as viruses. This relationship is often mediated by secondary metabolites produced by microorganisms. These secondary metabolites are known as specialized metabolites and are mostly volatile or non volatile compounds. These metabolites include terpenoids,sulfur compounds,indole compound and many more.
Methanotrophs are prokaryotes that metabolize methane as their source of carbon and chemical energy. They are bacteria or archaea,can grow aerobically or anaerobically,and require single-carbon compounds to survive.
Aeroplankton are tiny lifeforms that float and drift in the air,carried by wind. Most of the living things that make up aeroplankton are very small to microscopic in size,and many can be difficult to identify because of their tiny size. Scientists collect them for study in traps and sweep nets from aircraft,kites or balloons. The study of the dispersion of these particles is called aerobiology.
A hydrogenase is an enzyme that catalyses the reversible oxidation of molecular hydrogen (H2),as shown below:
The hydrogen cycle consists of hydrogen exchanges between biotic (living) and abiotic (non-living) sources and sinks of hydrogen-containing compounds.
Biohydrogen is H2 that is produced biologically. Interest is high in this technology because H2 is a clean fuel and can be readily produced from certain kinds of biomass,including biological waste. Furthermore some photosynthetic microorganisms are capable to produce H2 directly from water splitting using light as energy source.
Hydrogen-oxidizing bacteria are a group of facultative autotrophs that can use hydrogen as an electron donor. They can be divided into aerobes and anaerobes. The former use hydrogen as an electron donor and oxygen as an acceptor while the latter use sulphate or nitrogen dioxide as electron acceptors. Species of both types have been isolated from a variety of environments,including fresh waters,sediments,soils,activated sludge,hot springs,hydrothermal vents and percolating water.
Coenzyme F420 is a family of coenzymes involved in redox reactions in a number of bacteria and archaea. It is derived from coenzyme FO (7,8-didemethyl-8-hydroxy-5-deazariboflavin) and differs by having a oligoglutamyl tail attached via a 2-phospho-L-lactate bridge. F420 is so named because it is a flavin derivative with an absorption maximum at 420 nm.
The class Zetaproteobacteria is the sixth and most recently described class of the Pseudomonadota. Zetaproteobacteria can also refer to the group of organisms assigned to this class. The Zetaproteobacteria were originally represented by a single described species,Mariprofundus ferrooxydans,which is an iron-oxidizing neutrophilic chemolithoautotroph originally isolated from Kamaʻehuakanaloa Seamount in 1996 (post-eruption). Molecular cloning techniques focusing on the small subunit ribosomal RNA gene have also been used to identify a more diverse majority of the Zetaproteobacteria that have as yet been unculturable.
Methylobacter tundripaludum is a methane-oxidizing bacterium isolated in July 1996 from a wetland soil sampled near Ny-Ålesund,Svalbard. It is Gram-negative,rod-shaped,non-motile,non-spore forming,with type strain SV96T. Its genome has been sequenced.
Poribacteria are a candidate phylum of bacteria originally discovered in the microbiome of marine sponges (Porifera). Poribacteria are Gram-negative primarily aerobic mixotrophs with the ability for oxidative phosphorylation,glycolysis,and autotrophic carbon fixation via the Wood –Ljungdahl pathway. Poribacterial heterotrophy is characterised by an enriched set of glycoside hydrolases,uronic acid degradation,as well as several specific sulfatases. This heterotrophic repertoire of poribacteria was suggested to be involved in the degradation of the extracellular sponge host matrix.
Interspecies hydrogen transfer (IHT) is a form of interspecies electron transfer. It is a syntrophic process by which H2 is transferred from one organism to another,particularly in the rumen and other anaerobic environments.
Cable bacteria are filamentous bacteria that conduct electricity across distances over 1 cm in sediment and groundwater aquifers. Cable bacteria allow for long-distance electron transport,which connects electron donors to electron acceptors,connecting previously separated oxidation and reduction reactions. Cable bacteria couple the reduction of oxygen or nitrate at the sediment's surface to the oxidation of sulfide in the deeper,anoxic,sediment layers.
Atribacterota is a phylum of bacteria,which are common in anoxic sediments rich in methane. They are distributed worldwide and in some cases abundant in anaerobic marine sediments,geothermal springs,and oil deposits. Genetic analyzes suggest a heterotrophic metabolism that gives rise to fermentation products such as acetate,ethanol,and CO2. These products in turn can support methanogens within the sediment microbial community and explain the frequent occurrence of Atribacterota in methane-rich anoxic sediments. According to phylogenetic analysis,Atribacterota appears to be related to several thermophilic phyla within Terrabacteria or may be in the base of Gracilicutes. According to research,Atribacterota shows patterns of gene expressions which consists of fermentative,acetogenic metabolism. These expressions let Atribacterota to be able to create catabolic and anabolic functions which are necessary to generate cellular reproduction,even when the energy levels are limited due to the depletion of dissolved oxygen in the areas of sea waters,fresh waters,or ground waters.
The hydrothermal vent microbial community includes all unicellular organisms that live and reproduce in a chemically distinct area around hydrothermal vents. These include organisms in the microbial mat,free floating cells,or bacteria in an endosymbiotic relationship with animals. Chemolithoautotrophic bacteria derive nutrients and energy from the geological activity at Hydrothermal vents to fix carbon into organic forms. Viruses are also a part of the hydrothermal vent microbial community and their influence on the microbial ecology in these ecosystems is a burgeoning field of research.
Electric bacteria are forms of bacteria that directly consume and excrete electrons at different energy potentials without requiring the metabolization of any sugars or other nutrients. This form of life appears to be especially adapted to low-oxygen environments. Most life forms require an oxygen environment in which to release the excess of electrons which are produced in metabolizing sugars. In a low oxygen environment,this pathway for releasing electrons is not available. Instead,electric bacteria "breathe" metals instead of oxygen,which effectively results in both an intake of and excretion of electrical charges.
The holobiont concept is a renewed paradigm in biology that can help to describe and understand complex systems,like the host-microbe interactions that play crucial roles in marine ecosystems. However,there is still little understanding of the mechanisms that govern these relationships,the evolutionary processes that shape them and their ecological consequences. The holobiont concept posits that a host and its associated microbiota with which it interacts,form a holobiont,and have to be studied together as a coherent biological and functional unit to understand its biology,ecology,and evolution.
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