Biochemistry of hexose and pentose transformations in soil analyzed by position-specific labeling and 13C-PLFA

Soil microorganisms can overcome respiration inhibition by coupling intra- and extracellular metabolism: 13C metabolic tracing reveals the mechanisms

“…The 13 C recovery pattern in CO 2 was similar (C-14C-44C-24C-6) under both conditions. The high 13 C recovery from glucose C-1 position in CO 2 reveals that glucose was predominantly catabolized via the pentose phosphate pathway (Caspi et al, 2008;Dijkstra et al, 2011b;Apostel et al, 2015). Average 13 C recovery in CO 2 was 12% higher from inhibited soil compared with control.…”

“…Glucose lacks physical or chemical interactions with soil due to an absence of charged functional groups or hydrophobic parts (Fischer et al, 2010;Apostel et al, 2015), making it a potent candidate for tracing soil metabolic processes. Furthermore, the use of position-specifically labeled glucose allows the fate of individual molecular positions to be determined (Scandellari et al, 2009;Dijkstra et al, 2011a;Apostel et al, 2015), permitting detailed reconstruction of microbial metabolic pathways and de novo formed products . This provides the toolbox required to elucidate the source of CO 2 emission under respiration-inhibited conditions and thus to identify the mechanisms to overcome intoxication in contaminated environments.…”

“…At room temperatures, growth rate of Gram-negative bacteria is dependent upon the concentration of easily available substrate (Treonis et al, 2004). Therefore, they dominate the rhizosphere, where low molecular weight organic substances are present in high concentrations (Gunina et al, 2014;Apostel et al, 2015). In contrast, Gram-positive bacteria are typically abundant in bulk soil and incorporate C from old SOM (Kramer and Gleixner, 2006).…”

Sugars in soil and sweets for microorganisms: Review of origin, content, composition and fate

“…These pathways of sugars within the cells are described in detail in microbial biochemistry (Lengeler et al, 1999) and will not be reviewed here. As a result of internal recycling, sugar C can be included into various metabolic products such as other sugars, carboxylic acids or amino acids and can be used to construct cell structural components including cell membranes and cell walls (Gunina et al, 2014;Apostel et al, 2015), or cell polymers like DNA or RNA.…”

Microbial and enzymes response to nutrient additions in soils of Mt. Kilimanjaro region depending on land use

“…Low molecular weight substrates, e.g. glucose, are generally fully utilized within few hours [5,19]. Consequently, four weeks after application, glucose was completely exhausted, and therefore the soil micro-organisms reverted to attack native SOM and litter present in soil.…”