scholarly journals Bacterial Community Structure and Diversity in a Century-Old Manure-Treated Agroecosystem

2004 ◽  
Vol 70 (10) ◽  
pp. 5868-5874 ◽  
Author(s):  
H. Y. Sun ◽  
S. P. Deng ◽  
W. R. Raun
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Community Structure ◽  
Management Practices ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Pcr Amplification ◽  
Rrna Gene ◽  
Lime Treatment ◽  
Soil Microbial Community Structure ◽  
Treated Soil

ABSTRACT Changes in soil microbial community structure and diversity may reflect environmental impact. We examined 16S rRNA gene fingerprints of bacterial communities in six agroecosystems by PCR amplification and denaturing gradient gel electrophoresis (PCR-DGGE) separation. These soils were treated with manure for over a century or different fertilizers for over 70 years. Bacterial community structure and diversity were affected by soil management practices, as evidenced by changes in the PCR-DGGE banding patterns. Bacterial community structure in the manure-treated soil was more closely related to the structure in the untreated soil than that in soils treated with inorganic fertilizers. Lime treatment had little effect on bacterial community structure. Soils treated with P and N-P had bacterial community structures more closely related to each other than to those of soils given other treatments. Among the soils tested, a significantly higher number of bacterial ribotypes and a more even distribution of the bacterial community existed in the manure-treated soil. Of the 99 clones obtained from the soil treated with manure for over a century, two (both Pseudomonas spp.) exhibited 100% similarity to sequences in the GenBank database. Two of the clones were possible chimeras. Based on similarity matching, the remaining 97 clones formed six major clusters. Fifty-six out of 97 were assigned taxonomic units which grouped into five major taxa: α-, β-, and γ-Proteobacteria (36 clones), Acidobacteria (16 clones), Bacteroidetes (2 clones), Nitrospirae (1 clone), and Firmicutes (1 clone). Forty-one clones remained unclassified. Results from this study suggested that bacterial community structure was closely related to agroecosystem management practices conducted for over 70 years.

scholarly journals Impact of Protozoan Grazing on Bacterial Community Structure in Soil Microcosms

2002 ◽  
Vol 68 (12) ◽  
pp. 6094-6105 ◽  
Author(s):  
Regin Rønn ◽  
Allison E. McCaig ◽  
Bryan S. Griffiths ◽  
James I. Prosser
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Nutrient Solution ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Rrna Gene ◽  
Soil Microcosms ◽  
Protozoan Grazing ◽  
Protozoan Community

ABSTRACT The influence of grazing by a mixed assemblage of soil protozoa (seven flagellates and one amoeba) on bacterial community structure was studied in soil microcosms amended with a particulate resource (sterile wheat roots) or a soluble resource (a solution of various organic compounds). Sterilized soil was reinoculated with mixed soil bacteria (obtained by filtering and dilution) or with bacteria and protozoa. Denaturing gradient gel electrophoresis (DGGE) of PCR amplifications of 16S rRNA gene fragments, as well as community level physiological profiling (Biolog plates), suggested that the mixed protozoan community had significant effects on the bacterial community structure. Excising and sequencing of bands from the DGGE gels indicated that high-G+C gram-positive bacteria closely related to Arthrobacter spp. were favored by grazing, whereas the excised bands that decreased in intensity were related to gram-negative bacteria. The percentages of intensity found in bands related to high G+C gram positives increased from 4.5 and 12.6% in the ungrazed microcosms amended with roots and nutrient solution, respectively, to 19.3 and 32.9% in the grazed microcosms. Protozoa reduced the average bacterial cell size in microcosms amended with nutrient solution but not in the treatment amended with roots. Hence, size-selective feeding may explain some but not all of the changes in bacterial community structure. Five different protozoan isolates (Acanthamoeba sp., two species of Cercomonas, Thaumatomonas sp., and Spumella sp.) had different effects on the bacterial communities. This suggests that the composition of protozoan communities is important for the effect of protozoan grazing on bacterial communities.

Bacterial community structure and denitrifier (nir-gene) abundance in soil water and groundwater beneath agricultural land in tropical North Queensland, Australia

Soil Research ◽  
2011 ◽  
Vol 49 (1) ◽  
pp. 65 ◽  
Author(s):  
Steven A. Wakelin ◽  
Paul N. Nelson ◽  
John D. Armour ◽  
Velupillai Rasiah ◽  
Matthew J. Colloff
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Soil Water ◽  
Water Samples ◽  
Bacterial Community Structure ◽  
Management Practices ◽  
Agricultural Land ◽  
Rrna Gene ◽  
Gene Abundance ◽  
Copy Numbers

We explored the microbial ecology of water draining through the soil (lysimeter samples) and in the shallow aquifers (bore samples) underlying sugarcane and banana fields near the Great Barrier Reef (GBR), Australia. Lysimeter and bore water samples were collected and analysed chemically and with DNA fingerprinting methods (PCR-DGGE and clone library sequencing) to characterise the structure of the bacterial community. Bacterial communities in soil water and bore water were distinct (P < 0.05), and a primary factor linked with bacterial community structure was water pH (P < 0.05), particularly in water sampled from lysimeters. Irrespective of treatment, >80% of all rRNA gene sequences originated from proteobacteria. However, groundwater communities differed from those in soil water by greater occurrence of Neisseriales and Comamonadaceae (P < 0.01). qPCR was used to measure copy numbers of the nirK and nirS genes encoding NO-forming nitrite reductases. Copy numbers of both genes were greater in soil water samples than groundwater (P = 0.05), with the difference in nirK being greater under sugarcane than banana. These differences in nirK-gene abundance show that there is greater potential for denitrification in soil water under sugarcane, leading to low concentrations of nitrate in the underlying groundwater. This knowledge can be used towards development of soil and land-use management practices promoting bacterial denitrification in groundwater to lessen the undesirable ecological consequences where groundwater discharges lower in the GBR catchment zones.

Bacterial community structure inApis florealarvae analyzed by denaturing gradient gel electrophoresis and 16S rRNA gene sequencing

2014 ◽  
Vol 22 (5) ◽  
pp. 606-618 ◽  
Author(s):  
Prakaimuk Saraithong ◽  
Yihong Li ◽  
Kanokporn Saenphet ◽  
Zhou Chen ◽  
Panuwan Chantawannakul
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Gel Electrophoresis ◽  
Bacterial Community Structure ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Gene Sequencing ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Gradient Gel Electrophoresis ◽  
Rrna Gene Sequencing

scholarly journals Responses of Active Bacterial and Fungal Communities in Soils under Winter Wheat to Different Fertilizer and Pesticide Regimens

2004 ◽  
Vol 70 (5) ◽  
pp. 2692-2701 ◽  
Author(s):  
Martina S. Girvan ◽  
Juliet Bullimore ◽  
Andrew S. Ball ◽  
Jules N. Pretty ◽  
A. Mark Osborn
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Fungal Community ◽  
Bacterial Community Structure ◽  
Arbuscular Mycorrhizae ◽  
Management Practices ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Rrna Genes ◽  
Agricultural Practice ◽  
Good Agricultural Practice

ABSTRACT The composition of the active microbial (bacterial and fungal) soil community in an arable wheat field subjected to different management practices was examined at five times during a 1-year period. Field sections were fertilized either at good agricultural practice (GAP) levels or at reduced levels (0.5× GAP) and were inoculated with vesicular arbuscular mycorrhizae (VAM) at the same time. Field subsections were treated either with or without pesticides. Changes in the active microbial communities were investigated by denaturing gradient gel electrophoresis analysis of reverse transcription-PCR-amplified 16S and 18S rRNA. Microbial community structure was primarily determined by season, and the seasonal trends were similar for the fungal and bacterial components. Between-sample microbial heterogeneity decreased under a mature crop in the summer but increased following harvesting and plowing. Although similar overall trends were seen for the two microbial components, sample variability was greater for the fungal community than for the bacterial community. The greatest management effects were due to GAP fertilization, which caused increases in the bacterial numbers in the total and culturable communities. Microbial biomass similarly increased. GAP fertilization also caused large shifts in both the active bacterial community structure and the active fungal community structure and additionally resulted in a decrease in the heterogeneity of the active bacterial community. Pesticide addition did not significantly affect bacterial numbers or heterogeneity, but it led to major shifts in the active soil bacterial community structure. PCR primers specific for Glomales 25S rRNA genes were used to monitor the VAM population following inoculation. Glomales were detected initially only in VAM-inoculated field sections but were subsequently detected in noninoculated field sections as the season progressed. After plowing, the level of Glomales was reduced in noninoculated field sections but remained high in VAM-inoculated field sections. Inoculation of VAM correlated with elevated soil phosphate and carbon levels.

scholarly journals Both Leaf Properties and Microbe-Microbe Interactions Influence Within-Species Variation in Bacterial Population Diversity and Structure in the Lettuce (Lactuca Species) Phyllosphere

2010 ◽  
Vol 76 (24) ◽  
pp. 8117-8125 ◽  
Author(s):  
Paul J. Hunter ◽  
Paul Hand ◽  
David Pink ◽  
John M. Whipps ◽  
Gary D. Bending
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Community Structure ◽  
Population Diversity ◽  
Microbial Interactions ◽  
Soluble Carbohydrates ◽  
Rrna Gene ◽  
Species Variation ◽  
Clone Libraries ◽  
Microbe Interactions

ABSTRACT Morphological and chemical differences between plant genera influence phyllosphere microbial populations, but the factors driving within-species variation in phyllosphere populations are poorly understood. Twenty-six lettuce accessions were used to investigate factors controlling within-species variation in phyllosphere bacterial populations. Morphological and physiochemical characteristics of the plants were compared, and bacterial community structure and diversity were investigated using terminal restriction fragment length polymorphism (T-RFLP) profiling and 16S rRNA gene clone libraries. Plant morphology and levels of soluble carbohydrates, calcium, and phenolic compounds (which have long been associated with plant responses to biotic stress) were found to significantly influence bacterial community structure. Clone libraries from three representative accessions were found to be significantly different in terms of both sequence differences and the bacterial genera represented. All three libraries were dominated by Pseudomonas species and the Enterobacteriaceae family. Significant differences in the relative proportions of genera in the Enterobacteriaceae were detected between lettuce accessions. Two such genera (Erwinia and Enterobacter) showed significant variation between the accessions and revealed microbe-microbe interactions. We conclude that both leaf surface properties and microbial interactions are important in determining the structure and diversity of the phyllosphere bacterial community.

Characterization of bacterial community structure dynamics in a rat burn wound model using 16S rRNA gene sequencing

2022 ◽  
Author(s):  
Chen Zheng-li ◽  
Peng Yu ◽  
Wu Guo-sheng ◽  
Hong Xu-Dong ◽  
Fan Hao ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Bacterial Community Structure ◽  
Bacterial Species ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Sprague Dawley ◽  
Rrna Gene Sequencing

Abstract Burns destroy the skin barrier and alter the resident bacterial community, thereby facilitating bacterial infection. To treat a wound infection, it is necessary to understand the changes in the wound bacterial community structure. However, traditional bacterial cultures allow the identification of only readily growing or purposely cultured bacterial species and lack the capacity to detect changes in the bacterial community. In this study, 16S rRNA gene sequencing was used to detect alterations in the bacterial community structure in deep partial-thickness burn wounds on the back of Sprague-Dawley rats. These results were then compared with those obtained from the bacterial culture. Bacterial samples were collected prior to wounding and 1, 7, 14, and 21 days after wounding. The 16S rRNA gene sequence analysis showed that the number of resident bacterial species decreased after the burn. Both resident bacterial richness and diversity, which were significantly reduced after the burn, recovered following wound healing. The dominant resident strains also changed, but the inhibition of bacterial community structure was in a non-volatile equilibrium state, even in the early stage after healing. Furthermore, the correlation between wound and environmental bacteria increased with the occurrence of burns. Hence, the 16S rRNA gene sequence analysis reflected the bacterial condition of the wounds better than the bacterial culture. 16S rRNA sequencing in the Sprague-Dawley rat burn model can provide more information for the prevention and treatment of burn infections in clinical settings and promote further development in this field.

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