Thanavit Jirapanjawat

Monash University (Australia) · School of Biological Sciences, Clayton

Wetland tree stems have recently been shown to be a major source of methane emissions. However, the microbial communities associated within these stems (the 'caulosphere') and their contribution to biogeochemical cycling of methane and other compounds remain poorly understood. Here, we reveal that specialised microbial communities inhabit the bark...

Most aerated cave ecosystems are assumed to be oligotrophic given they receive minimal inputs of light energy. Diverse microorganisms have nevertheless been detected within caves, though it remains unclear what strategies enable them to meet their energy and carbon needs. Here we determined the processes and mediators of primary production in aerat...

In marine sediments, microbial degradation of organic matter under anoxic conditions is generally thought to proceed through fermentation to volatile fatty acids (VFA), which are then oxidized to CO2 coupled to the reduction of terminal electron acceptors (e.g. nitrate, iron, manganese and sulfate). It has been suggested that, in environments with...

In marine sediments, microbial degradation of organic matter under anoxic conditions is generally thought to proceed through fermentation to volatile fatty acids (VFA), which are then oxidized to CO2 coupled to the reduction of terminal electron acceptors (e.g. nitrate, iron, manganese and sulfate). It has been suggested that, in environments with...

Globally, the anaerobic bacterium Clostridium perfringens causes severe disease in a wide array of hosts; however, C. perfringens strains are also carried asymptomatically. Accessory genes are responsible for much of the observed phenotypic variation and virulence within this species, with toxins frequently encoded on conjugative plasmids and many...

Molecular hydrogen (H2) is an abundant and readily accessible energy source in marine systems, but it remains unknown whether marine microbial communities consume this gas. Here we use a suite of approaches to show that marine bacteria consume H2 to support growth. Genes for H2-uptake hydrogenases are prevalent in global ocean metagenomes, highly e...

Synthesis of monodisperse guanylated oligomers through reversible addition fragmentation chain transfer (RAFT) polymerization of 2-boc aminoethyl acrylate followed by flash chromatography is described. To achieve antimicrobial action, the RAFT-derived protected...

Quantitative polymerase chain reaction (qPCR) is a gold standard method for the detection and quantification of pathogenic organisms. Standard qPCR is inexpensive, sensitive and highly specific to the pathogen of interest. While qPCR assays can be multiplexed to allow the detection of multiple organisms in one reaction, it is prohibitively labour i...

Molecular hydrogen (H2) and carbon monoxide (CO) are supersaturated in seawater relative to the atmosphere and hence are readily accessible energy sources for marine microbial communities. Yet while marine CO oxidation is well-described, it is unknown whether seawater communities consume H2. Here we integrated genome-resolved metagenomics, biogeoch...

Significance Diverse microbial life has been detected in the cold desert soils of Antarctica once thought to be barren. Here, we provide metagenomic, biogeochemical, and culture-based evidence that Antarctic soil microorganisms are phylogenetically and functionally distinct from those in other soils and adopt various metabolic and ecological strate...

Significance Termites are textbook examples of the “extended phenotype” given their ability to construct complex mounds and regulate environments. Here, we show that termites also control microbial composition and biogeochemical cycling in their mounds through their emissions of hydrogen. These emissions drive remarkable enrichments of mound bacter...

Background: Multiple bacteria, viruses, protists, and helminths cause enteric infections that greatly impact human health and wellbeing. These enteropathogens are transmited via several pathways through human, animal, and environmental reservoirs. Individual qPCR assays have been extensively used to detect enteropathogens within these types of sam...

Soil microorganisms globally are thought to be sustained primarily by organic carbon sources. Certain bacteria also consume inorganic energy sources such as trace gases, but they are presumed to be rare community members, except within some oligotrophic soils. Here we combined metagenomic, biogeochemical and modelling approaches to determine how so...

Atmospheric trace gases such as dihydrogen (H2), carbon monoxide (CO) and methane (CH4) play important roles in microbial metabolism and biogeochemical cycles. Analysis of these gases at trace levels requires reliable storage of discrete samples of low volume. While commercial sampling vials such as Exetainers® have been tested for CH4 and other gr...

Background Multiple bacteria, viruses, protists, and helminths cause enteric infections that greatly impact human health and wellbeing. These enteropathogens are transmitted via several pathways through human, animal, and environmental reservoirs. Individual quantitative PCR (qPCR) assays have been extensively used to detect enteropathogens within...

Atmospheric trace gases such as dihydrogen (H2), carbon monoxide (CO) and methane (CH4) play important roles in microbial metabolism and biogeochemical cycles. Analysis of these gases at trace levels requires reliable storage of discrete samples of low volume. While commercial sampling vials such as Exetainers® have been tested for CH4 and other gr...

Termite mounds have recently been confirmed to mitigate approximately half of termite methane (CH4) emissions, but the aerobic CH4 oxidising bacteria (methanotrophs) responsible for this consumption have not been resolved. Here, we describe the abundance, composition and CH4 oxidation kinetics of the methanotroph communities in the mounds of three...

Most aerobic bacteria exist in dormant states within natural environments. In these states, they endure adverse environmental conditions such as nutrient starvation by decreasing metabolic expenditure and using alternative energy sources. In this study, we investigated the energy sources that support persistence of two aerobic thermophilic strains...

Bacteria within aerated environments often exist within a variety of dormant forms. In these states, bacteria endure adverse environmental conditions such as organic carbon starvation by decreasing metabolic expenditure and using alternative energy sources. In this study, we investigated the energy sources that facilitate the persistence of the env...

F420 is a microbial cofactor that mediates a wide range of physiologically important and industrially relevant redox reactions, including in methanogenesis and tetracycline biosynthesis. This deazaflavin comprises a redox-active isoalloxazine headgroup conjugated to a lactyloligoglutamyl tail. Here we studied the catalytic significance of the oligo...

An unusual aspect of actinobacterial metabolism is the use of the redox cofactor F420. Studies have shown that actinobacterial F420H2-dependent reductases promiscuously hydrogenate diverse organic compounds in biodegradative and biosynthetic processes. These enzymes therefore represent promising candidates for next-generation industrial biocatalyst...

A defining feature of mycobacterial redox metabolism is the use of an unusual deazaflavin cofactor, F420. This cofactor enhances the persistence of environmental and pathogenic mycobacteria, including after antimicrobial treatment, although the molecular basis for this remains to be understood. In this work, we explored our hypothesis that F420 enh...