Microcalorimetric measurements of the microbial activities of single- and mixed-species with trivalent iron in soil.
A microcalorimetric technique was applied to a series of experiments to follow the toxic effect caused by the trivalent iron on the single and mixed microbes in sterilized soil that was inoculated with the single Bacillus subtilis (B. subtilis) (prokaryotic bacterium), single Candida humicola (C. humicola) (eukaryotic fungus) and the mixed-species. The microbial activity was stimulated by the addition of 5.0mg glucose and 5.0mg ammonium sulfate under a 35% controlled humidity in the studied soil samples of 1.2g. The power-time curves from every experiment were analyzed, and from these analyses characteristic parameters, such as growth rate constant (k) and total thermal effect (Q) which can reflect the biochemical reactions were determined. The mixed-species have moderate tolerance to the iron overload, comparing with single species, and exhibit synergistic interaction in exponential growth phase (0-400.0 microg mL(-1)). Meanwhile, there is no much difference in the thermal effect (Q) per gram soil sample for the single and mixed culture. This also validates that the nutrient substances in natural environment determine the organisms' metabolic activities. Ultraviolet-visible spectrophotometry and dissolved oxygen sensor also were successfully applied to reflect the activities of B. subtilis and C. humicola in the pure culture. The investigation could provide insight into the microbial ecology of bacteria and fungi in ecological niches.
Wang
Fei
F
School of Environmental Studies and Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health, China University of Geosciences, 430074 Wuhan, PR China.
Yao
Jun
J
School of Environmental Studies and Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health, China University of Geosciences, 430074 Wuhan, PR China. Electronic address: yaojun@cug.edu.cn.
Chen
Huilun
H
School of Environmental Studies and Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health, China University of Geosciences, 430074 Wuhan, PR China.
Zhou
Yong
Y
School of Environmental Studies and Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health, China University of Geosciences, 430074 Wuhan, PR China.
Chen
Yanjiao
Y
School of Environmental Studies and Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health, China University of Geosciences, 430074 Wuhan, PR China.
Chen
Haiyan
H
School of Environmental Studies and Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health, China University of Geosciences, 430074 Wuhan, PR China.
Gai
Nan
N
School of Environmental Studies and Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health, China University of Geosciences, 430074 Wuhan, PR China.
Zhuang
Rensheng
R
School of Environmental Studies and Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health, China University of Geosciences, 430074 Wuhan, PR China.
Tian
Lin
L
School of Environmental Studies and Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health, China University of Geosciences, 430074 Wuhan, PR China.
Maskow
Thomas
T
UFZ Centre for Environmental Research Leipzig, 04318 Leipzig, Germany.
Ceccanti
Brunello
B
Institute of Ecosystem Studies, Research Unit of Pisa, National Council of Researches, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa, Italy.
Trebse
Polonca
P
Laboratory for Environmental Research, University of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia.
Zaray
Gyula
G
Department of Chemical Technology and Environmental Chemistry, Eötvös University, P.O. Box 32, H-1518 Budapest, Hungary.
D001412:Bacillus subtilis / Q000187:drug effects / Q000254:growth & development; D002118:Calcium / Q000032:analysis; D002151:Calorimetry / Q000379:methods; D002175:Candida / Q000187:drug effects / Q000254:growth & development; D002712:Chlorides; D005290:Ferric Compounds / Q000494:pharmacology*; D008274:Magnesium / Q000032:analysis; D008832:Microchemistry / Q000379:methods; D010100:Oxygen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D011188:Potassium / Q000032:analysis; D012964:Sodium / Q000032:analysis; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D013053:Spectrophotometry
D002712:Chlorides; D005290:Ferric Compounds; D012987:Soil; D010758:Phosphorus; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D010100:Oxygen; D002118:Calcium; C024555:ferric chloride