Evaluation of the selective respiratory inhibition method for measuring the ratio of fungal:bacterial activity in acid agricultural soils

Velvis, H.

doi:10.1007/s003740050325

Cited by 51 publications

(26 citation statements)

References 21 publications

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“…2). However, non-target inhibition by cycloheximide has been reported (Velvis, 1997) and it cannot be discounted that prokaryotes alone are responsible for CO consumption in this soil. The lack of change in headspace CO in soil simultaneously treated with both antibiotics may result from equilibrium between production and a lowered rate of consumption of CO. Alternatively, this soil may not produce CO and the synergistic effect of both antibiotics totally eliminated CO consumption.…”

Section: Effect Of Selective Inhibitors On Co Oxidationmentioning

confidence: 83%

Carbon monoxide consumption in upland boreal forest soils

Whalen

Reeburgh

2001

Soil Biology and Biochemistry

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Biological consumption by aerobic soils is an important, but poorly understood sink for carbon monoxide, a chemically active atmospheric trace gas. We used laboratory experiments to characterize CO consumption in representative soils of the northern boreal forest. This ecozone may be important in atmospheric CO consumption because it occupies 13% of the world's landmass. Soils initially showing net CO consumption emitted CO following biocidal treatment (ethylene oxide or g-irradiation), indicating that CO consumption was biologically mediated. The use of selective inhibitors (cycloheximide, streptomycin) suggested that both prokaryotes and eukaryotes were responsible. Soil pro®les generally indicated net consumption of atmospheric CO to a depth of 15 cm (concentrations decreasing from~150 to ,20 nl l 21 with depth) and a dynamic equilibrium between CO production and consumption in deeper soils (concentrations nearly constant at ,20 nl l 21 ). Soils to a depth of 30 cm showed vigorous CO-consuming activity, suggesting that local CO production provided necessary substrate beneath the 15 cm surface zone of atmospheric in¯uence. Radiotracer experiments demonstrated that only 5±7% of assimilated 14 CO was incorporated into biomass in 5 cm core sections taken to 30 cm and that ,1% of assimilated 14 CO was incorporated into cellular material by a methanotroph isolated from this soil. Collectively, these data point to nonutilitarian oxidation of CO by a diverse microbial community. Carbon monoxide oxidation increased with increasing temperature over the range 4±348C, with a Q 10 of 1.8. Apparent half-saturation constants (8±36 (ml CO l 21 ), and maximum rates of CO consumption (0.7±2.7 mg g dry soil 21 h 21 ) were comparable to reports for diverse temperate soil environments, pointing to a fundamental similarity among CO-consuming microbial communities in aerobic soils. q

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Section: Effect Of Selective Inhibitors On Co Oxidationmentioning

confidence: 83%

Carbon monoxide consumption in upland boreal forest soils

Whalen

Reeburgh

2001

Soil Biology and Biochemistry

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“…Using this technique, increases in the fungal biomass/bacterial biomass ratio of 4.5-fold between pH 7 and 3 (12) and of twoto sixfold between pH 6 and 3 (17) have been reported. However, the partitioning of potential respiration by using antibiotics to estimate fungal and bacterial biomasses has repeatedly been challenged (56,64). Still, it is noteworthy that this biomass technique, which inherently relies on active microorganisms, has high responsiveness to pH effects.…”

Section: Vol 75 2009 Contrasting Ph Effects On Fungal and Bacterialmentioning

confidence: 99%

Contrasting Soil pH Effects on Fungal and Bacterial Growth Suggest Functional Redundancy in Carbon Mineralization

Rousk

Brookes

Bååth

2009

Appl Environ Microbiol

1,391

710

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The influence of pH on the relative importance of the two principal decomposer groups in soil, fungi and bacteria, was investigated along a continuous soil pH gradient at Hoosfield acid strip at Rothamsted Research in the United Kingdom. This experimental location provides a uniform pH gradient, ranging from pH 8.3 to 4.0, within 180 m in a silty loam soil on which barley has been continuously grown for more than 100 years. We estimated the importance of fungi and bacteria directly by measuring acetate incorporation into ergosterol to measure fungal growth and leucine and thymidine incorporation to measure bacterial growth. The growthbased measurements revealed a fivefold decrease in bacterial growth and a fivefold increase in fungal growth with lower pH. This resulted in an approximately 30-fold increase in fungal importance, as indicated by the fungal growth/bacterial growth ratio, from pH 8.3 to pH 4.5. In contrast, corresponding effects on biomass markers for fungi (ergosterol and phospholipid fatty acid [PLFA] 18:26,9) and bacteria (bacterial PLFAs) showed only a two-to threefold difference in fungal importance in the same pH interval. The shift in fungal and bacterial importance along the pH gradient decreased the total carbon mineralization, measured as basal respiration, by only about one-third, possibly suggesting functional redundancy. Below pH 4.5 there was universal inhibition of all microbial variables, probably derived from increased inhibitory effects due to release of free aluminum or decreasing plant productivity. To investigate decomposer group importance, growth measurements provided significantly increased sensitivity compared with biomass-based measurements.

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“…13,19 The technique was first introduced by Anderson and Domsch 20 and was then modified for application to agricultural and forest soils. 21 Different bactericides (e.g.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of antibacterial and antifungal compounds for selective inhibition of denitrification in soils

Ladan

Jacinthe

2016

Environ. Sci.: Processes Impacts

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Nitrous oxide (N2O) is an atmospheric constituent implicated in climate warming and stratospheric ozone depletion. Both bacteria and fungi participate in N2O production, but information is lacking with regard to the relative contribution of bacterial and fungal denitrifiers to the denitrification process in agricultural soils. The selective inhibition technique (SI) is widely used to assess the contribution of different groups of microbes to soil processes, but success of the technique depends on the effectiveness of the inhibitors.In this study, laboratory experiments were conducted to assess the contribution of bacteria and fungi to denitrification using soils from a woodlot, agricultural fields under conventional plowing (PT), and no-till for either 50 years (long-term) or 11 years (medium-term). A selective inhibition (SI) technique was developed using two bactericides (streptomycin, bronopol) and two fungicides (cycloheximide, captan) applied at different rates (0-32 mg g -1 soil). Regardless of application rate, streptomycin and cycloheximide were not effective inhibitors of denitrification, with degree of inhibition only between 2 and 20% relative to controls. These results are significant given the wide use of these products in SI studies. However, the bactericide bronopol and the fungicide captan effectively inhibited denitrification, with the strongest inhibition observed at an application rate of 16 mg g -1 soil. The ratio of fungal to bacterial denitrification activity (F:B) was generally less than 1, indicating a dominance of bacteria in denitrification activity in the soils investigated. However, an increase in F:B ratio from 0.24 in mediumterm NT to 0.87 in long-term NT soils was noted, suggesting perhaps a progressive increase in the role of fungal denitrifiers with longer duration of NT farming.3

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Evaluation of the selective respiratory inhibition method for measuring the ratio of fungal:bacterial activity in acid agricultural soils

Cited by 51 publications

References 21 publications

Carbon monoxide consumption in upland boreal forest soils

Carbon monoxide consumption in upland boreal forest soils

Contrasting Soil pH Effects on Fungal and Bacterial Growth Suggest Functional Redundancy in Carbon Mineralization

Evaluation of antibacterial and antifungal compounds for selective inhibition of denitrification in soils

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