scholarly journals Fungi Dominated the Incorporation of 13C-CO2 into Microbial Biomass in Tomato Rhizosphere Soil under Different CO2 Concentrations

2021 ◽  
Vol 9 (10) ◽  
pp. 2121
Author(s):  
Hehua Wang ◽  
Juan Wang ◽  
Chaorong Ge ◽  
Huaiying Yao
Keyword(s):  
Microbial Biomass ◽  
Phospholipid Fatty Acid ◽  
Dominant Role ◽  
Mantel Test ◽  
Stable Isotope Probing ◽  
Tomato Root ◽  
Gram Positive Bacteria ◽  
Soil Systems ◽  
Co2 Concentrations ◽  
Microbial Community Structures

An elevated CO2 (eCO2) fumigation experiment was carried out to study the influence of various CO2 concentrations on microorganisms involved in the incorporation of root-derived C in greenhouse soil systems. In this study, 400 and 800 µmol·mol−1 CO2 fumigation treatments were conducted during tomato planting. Phospholipid fatty acid (PLFA) profiling based on the stable isotope probing (SIP) technique was applied to trace active microorganisms. The absolute total abundance of 13C-PLFAs was much higher under eCO2 treatment. Most of the 13C-CO2 was incorporated into the 13C-PLFAs 18:2ω6,9 (fungi), 16:0 (general PLFA), 18:1ω9c (Gram-negative bacteria, G−) and i17:0 (Gram-positive bacteria, G+) via rhizodeposition from tomato under ambient CO2 (aCO2) and eCO2 treatments, suggesting similar responses of active microorganisms to different CO2 treatments. However, the fungi (characterized by the 13C-PLFA 18:2ω6,9) played a much more dominant role in the incorporation of root-derived C under eCO2. Actinomycetes, marked by the 13C-PLFA 10-Me-18:0, occurred only on labeling day 15 under the eCO2 treatment, indicating that the actinomycetes fed on both soil organic carbon and fresh rhizodeposition. It was indicated that eCO2 significantly affected microbial biomass and microbial community structures involved in the incorporation of 13C-CO2 via tomato root secretions, as supported by Adonis analysis and the Mantel test.

scholarly journals Biome-Level Biogeography of Streambed Microbiota

2008 ◽  
Vol 74 (10) ◽  
pp. 3014-3021 ◽  
Author(s):  
Robert H. Findlay ◽  
Christine Yeates ◽  
Meredith A. J. Hullar ◽  
David A. Stahl ◽  
Louis A. Kaplan
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Bacterial Community ◽  
Microbial Community Structure ◽  
Bacterial Community Structure ◽  
Phospholipid Fatty Acid ◽  
Principal Component ◽  
Community Structures ◽  
Microbial Community Structures

ABSTRACT A field study was conducted to determine the microbial community structures of streambed sediments across diverse geographic and climatic areas. Sediment samples were collected from three adjacent headwater forest streams within three biomes, eastern deciduous (Pennsylvania), southeastern coniferous (New Jersey), and tropical evergreen (Guanacaste, Costa Rica), to assess whether there is biome control of stream microbial community structure. Bacterial abundance, microbial biomass, and bacterial and microbial community structures were determined using classical, biochemical, and molecular methods. Microbial biomass, determined using phospholipid phosphate, was significantly greater in the southeastern coniferous biome, likely due to the smaller grain size, higher organic content, and lower levels of physical disturbance of these sediments. Microbial community structure was determined using phospholipid fatty acid (PLFA) profiles and bacterial community structure from terminal restriction fragment length polymorphism and edited (microeukaryotic PLFAs removed) PLFA profiles. Principal component analysis (PCA) was used to investigate patterns in total microbial community structure. The first principal component separated streams based on the importance of phototrophic microeukaryotes within the community, while the second separated southeastern coniferous streams from all others based on increased abundance of fungal PLFAs. PCA also indicated that within- and among-stream variations were small for tropical evergreen streams and large for southeastern coniferous streams. A similar analysis of bacterial community structure indicated that streams within biomes had similar community structures, while each biome possessed a unique streambed community, indicating strong within-biome control of stream bacterial community structure.

scholarly journals Microbial Population Changes during Bioremediation of an Experimental Oil Spill

1999 ◽  
Vol 65 (8) ◽  
pp. 3566-3574 ◽  
Author(s):  
Sarah J. MacNaughton ◽  
John R. Stephen ◽  
Albert D. Venosa ◽  
Gregory A. Davis ◽  
Yun-Juan Chang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Bacterial Community ◽  
Oil Spill ◽  
Phospholipid Fatty Acid ◽  
Community Structures ◽  
Gram Negative ◽  
Dgge Analysis ◽  
16S Rdna Pcr ◽  
Microbial Community Structures ◽  
Plfa Analysis

ABSTRACT Three crude oil bioremediation techniques were applied in a randomized block field experiment simulating a coastal oil spill. Four treatments (no oil control, oil alone, oil plus nutrients, and oil plus nutrients plus an indigenous inoculum) were applied. In situ microbial community structures were monitored by phospholipid fatty acid (PLFA) analysis and 16S rDNA PCR-denaturing gradient gel electrophoresis (DGGE) to (i) identify the bacterial community members responsible for the decontamination of the site and (ii) define an end point for the removal of the hydrocarbon substrate. The results of PLFA analysis demonstrated a community shift in all plots from primarily eukaryotic biomass to gram-negative bacterial biomass with time. PLFA profiles from the oiled plots suggested increased gram-negative biomass and adaptation to metabolic stress compared to unoiled controls. DGGE analysis of untreated control plots revealed a simple, dynamic dominant population structure throughout the experiment. This banding pattern disappeared in all oiled plots, indicating that the structure and diversity of the dominant bacterial community changed substantially. No consistent differences were detected between nutrient-amended and indigenous inoculum-treated plots, but both differed from the oil-only plots. Prominent bands were excised for sequence analysis and indicated that oil treatment encouraged the growth of gram-negative microorganisms within the α-proteobacteria andFlexibacter-Cytophaga-Bacteroides phylum. α-Proteobacteria were never detected in unoiled controls. PLFA analysis indicated that by week 14 the microbial community structures of the oiled plots were becoming similar to those of the unoiled controls from the same time point, but DGGE analysis suggested that major differences in the bacterial communities remained.

scholarly journals How Elemental Stoichiometric Ratios in Microorganisms Respond to Thinning Management in Larix principis-rupprechtti Mayr. Plantations of the Warm Temperate Zone in China

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 684
Author(s):  
Mengke Cai ◽  
Shiping Xing ◽  
Xiaoqing Cheng ◽  
Li Liu ◽  
Xinhao Peng ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Temperature ◽  
Microbial Communities ◽  
Microbial Biomass Carbon ◽  
Gram Negative Bacteria ◽  
Medium Density ◽  
Biomass Carbon ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Stoichiometric Ratios

The stoichiometric ratios of elements in microorganisms play an important role in biogeochemical cycling and evaluating the nutritional limits of microbial growth, but the effects of thinning treatment on the stoichiometric ratio of carbon, nitrogen, and phosphorus in microorganisms remain unclear. We conducted research in a Larix principis-rupprechtti Mayr. plantation to determine the main factors driving microbial carbon (C): nitrogen (N): phosphorus (P) stoichiometry following thinning and the underlying mechanisms of these effects. The plantation study varied in thinning intensity from 0% tree removal (control), 15% tree reduction (high density plantation, HDP), 35% tree reduction (medium density plantation, MDP), and 50% tree reduction (low density plantation, LDP). Our results indicated that medium density plantation significantly increased litter layer biomass, soil temperature, and other soil properties (e.g., soil moisture and nutrient contents). Understory vegetation diversity (i.e., shrub layer and herb layer) was highest in the medium density plantation. Meanwhile, thinning had a great influence on the biomass of microbial communities. For example, the concentration of phospholipid fatty acids (PLFA) for bacteria and fungi in the medium density plantation (MDP) was significantly higher than in other thinning treatments. Combining Pearson correlation analysis, regression modeling, and stepwise regression demonstrated that the alteration of the microbial biomass carbon: nitrogen was primarily related to gram-positive bacteria, gram-negative bacteria, soil temperature, and soil available phosphorus. Variation in bacteria, actinomycetes, gram-positive bacteria, gram–negative bacteria, and soil total phosphorus was primarily associated with shifts in microbial biomass carbon: phosphorus. Moreover, changes in microbial biomass nitrogen: phosphorus were regulated by actinomycetes, gram-negative bacteria, and soil temperature. In conclusion, our research indicates that the stoichiometric ratios of elements in microorganisms could be influenced by thinning management, and emphasizes the importance of soil factors and microbial communities in driving soil microbial stoichiometry.

scholarly journals Soil Microbial Community Structure and Physicochemical Properties in Amomum tsaoko-based Agroforestry Systems in the Gaoligong Mountains, Southwest China

2019 ◽  
Vol 11 (2) ◽  
pp. 546 ◽  
Author(s):  
Guizhou Liu ◽  
Man Jin ◽  
Chuantao Cai ◽  
Chaonan Ma ◽  
Zhongsuzhi Chen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Physicochemical Properties ◽  
Phospholipid Fatty Acid ◽  
Soil Microbial Communities ◽  
Total Carbon ◽  
Native Forest ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
The Impact

Amomum tsaoko is cultivated in forests of tropical and subtropical regions of China, and the planting area is expanding gradually. However, little attention has been paid to the impact of A. tsaoko cultivation on the soil characteristics of the regions. We analyzed the effects of the A. tsaoko-forest agroforestry system (AFs) on the composition of soil microbial communities with increasing stand ages. We also compared the soil physicochemical properties, microbial biomass, and phospholipid fatty acid (PLFA) composition between native forest (NF) and AFs. The results showed that the level of total carbon, nitrogen, and organic matter dramatically dropped in AFs with increasing stand ages. pH affected other soil properties and showed close correlation to total carbon (P = 0.0057), total nitrogen (P = 0.0146), organic matter (P = 0.0075), hydrolyzable nitrogen (P = 0.0085), available phosphorus (P < 0.0001), and available potassium (P = 0.0031). PLFAs of bacteria (F = 4.650, P = 0.037), gram-positive bacteria (F = 6.640, P = 0.015), anaerobe (F = 5.672, P = 0.022), and total PLFA (F = 4.349, P = 0.043) were significantly affected by different treatments, with the greatest value for NF treatment, and least value for AF5. However, the microbial biomass declined during the initial 5 years of cultivation, but it reached the previous level after more than 10 years of cultivation. Our research suggests that AFs is a profitable land-use practice in the Gaoligong Mountains and that AFs showed a recovering trend of the soil nutrient condition with increasing stand ages. However, the severe loss of nitrogen in the soil of AFs requires additional nitrogen during cultivation to restore it to pre-cultivation levels.

Impact of Humics and Plants on Microbial Community and Petroleum Hydrocarbon Degradation in Contaminated Soil

2013 ◽  
Vol 726-731 ◽  
pp. 131-140
Author(s):  
Hai Hua Jiao ◽  
Kai Wang ◽  
Jian Gang Pan ◽  
De Cai Jin ◽  
Zhan Bin Huang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Soil Microbial Community ◽  
Petroleum Hydrocarbon ◽  
Phospholipid Fatty Acid ◽  
Principal Component ◽  
Total Petroleum Hydrocarbon ◽  
Crop Species ◽  
Functional Activities ◽  
Soil Microbial ◽  
Gram Positive Bacteria

A greenhouse pot experiment, in which 3 different crops (wheat, cabbage, spinach) were cultivated in soil with and without humics (HS), was conducted to evaluate the effect of HS on soil microbiological properties. Phospholipid fatty acid (PLFA) profiles were analyzed to reveal the microbial community structure. As a measure of the functional activity of soil microbial community, the ratio of degraded to total petroleum hydrocarbon in soil was estimated. The results indicated that HS had an important effect on the soil microbial community and its functional activities. First, the principal component analysis (PCA) of the PLFA signatures revealed marked changes between soil with HS and without HS. In addition, the total amount and the profile of PLFA were significantly different between the untreated and HS-amended soils. Using PLFA patterns as a biomarker, it was found that gram-positive bacteria (G+) were more sensitive to HS than gram-negative bacteria (G-), and the biomass of G+ was higher in soil with HS than in that without HS. Second, the crop could stimulate the growth of soil microorganisms; however, the differences depended clearly on the crop species. The G+ and G- biomass was increased in spinach soil containing HS, but was decreased in wheat and cabbage soils. The population of fungi was increased in wheat and spinach soils containing HS, but was decreased in cabbage soil. The population of actinomycetes was increased in cabbage soil, but was decreased in wheat and spinach soils containing HS. Third, the ratio of degraded to total petroleum hydrocarbon was also affected by the HS treatment. It was slightly increased in soil with HS treatment, but a significant change depended on the crop species. In general, fatty acids ranged from C13 to C19. In total, 25 different PLFAs were identified, including saturated (SAT), monounsaturated (MUFA), branched (BR), and polyunsaturated (PUFA) species. There was a clear difference in the PLFA composition between soils with and without HS.

scholarly journals Ester Linked Fatty Acid (ELFA) method should be used with caution for interpretating soil microbial communities and their relationships with environmental variables in forest soils

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251501
Author(s):  
Wenjuan Yu ◽  
Huanhuan Gao ◽  
Hongzhang Kang
Keyword(s):  
Fatty Acid ◽  
Microbial Biomass ◽  
Microbial Communities ◽  
Forest Soils ◽  
Environmental Variables ◽  
Phospholipid Fatty Acid ◽  
Soil Microbial Communities ◽  
Environmental Drivers ◽  
Soil Microbial ◽  
Forest Sites

As an alternative for phospholipid fatty acid (PLFA) analysis, a simpler ester linked fatty acid (ELFA) analysis has been developed to characterize soil microbial communities. However, few studies have compared the two methods in forest soils where the contribution of nonmicrobial sources may be larger than that of microbial sources. Moreover, it remains unclear whether the two methods yield similar relationships of microbial biomass and composition with environmental variables. Here, we compared PLFA and ELFA methods with respect to microbial biomass and composition and their relationships with environmental variables in six oriental oak (Quercus variabilis) forest sites along a 1500-km latitudinal gradient in East China. We found that both methods had a low sample-to-sample variability and successfully separated overall community composition of sites. However, total, bacterial, and fungal biomass, the fungal-to-bacterial ratio, and the gram-positive to gram-negative bacteria ratio were not significantly or strongly correlated between the two methods. The relationships of these microbial properties with environmental variables (pH, precipitation, and clay) greatly differed between the two methods. Our study indicates that despite its simplicity, the ELFA method may not be as feasible as the PLFA method for investigating microbial biomass and composition and for identifying their dominant environmental drivers, at least in forest soils.

Effect of solids retention time on the performance and biological characteristics of a membrane bioreactor

2001 ◽  
Vol 43 (11) ◽  
pp. 43-50 ◽  
Author(s):  
N. Cicek ◽  
J. Macomber ◽  
J. Davel ◽  
M. T. Suidan ◽  
J. Audic ◽  
...  
Keyword(s):  
Membrane Bioreactor ◽  
Phospholipid Fatty Acid ◽  
Pilot Scale ◽  
Yeast Cells ◽  
Nitrogen And Phosphorus ◽  
Mixed Liquor ◽  
Gram Positive Bacteria ◽  
Solids Retention ◽  
Biolog Analysis ◽  
Eukaryotic Organisms

The purpose of this study was to compare the performance of a pilot-scale membrane bioreactor (MBR) in the treatment of municipal strength wastewater at solid retention times (SRTs) ranging from 30 days to two days. Cumulative nitrogen and phosphorus mass balances resulted in closures exceeding 90% at each steady state period. Biomass production rate and biomass viability generally increased with decreasing SRT, whereas overall enzymatic activity did not change significantly at most SRTs, but was highest at the two day SRT. Nitrification decreased at two day SRT but did not fail completely. At higher SRTs, nitrification was not noticeably affected by the sludge age. Phospholipid fatty acid (PLFA) analysis showed substantially diverse biomass in the sludge at different SRTs. Different ratios of gram positive bacteria, eukaryotic organisms, and yeast cells were observed in the mixed liquor at varying SRTs. On the other hand, BIOLOG analysis indicated that the overall capacity of the biomass to degrade different carbon substrates did not change significantly at different SRTs. The concentration of metals in the MBR mixed liquor declined steadily with decreasing SRT. The MBR effluent contained negligible amounts of Fe, Zn, Mn, and Co at each condition, indicating the retention of these metals regardless of the SRT.

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