Variation in archaeal and bacterial community profiles and their functional metabolic predictions under the influence of pure and mixed fertilizers in paddy soil.

Impact of environmental perturbations i.e., nitrogen (N), phosphorus (P), potassium (K), and rice straw (Rs) on the dynamics of soil bacterial and archaeal communities are multifactor dependent and seeks a contemporary approach to study underlying mechanisms.

Distribution of ammonia-oxidizing archaea and bacteria along an engineered coastal ecosystem in subtropical China.

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) are the crucial players in nitrogen cycle. Both AOA and AOB were examined along a gradient of human activity in a coastal ecosystem from intertidal zone, grassland, and Casuarina equisetifolia forest to farmland. Results showed that the farmland soils had noticeably higher nitrate-N, available P than soils in the other three sites.

Risk assessment and source analysis of soil heavy metal pollution from lower reaches of Yellow River irrigation in China.

The level of concentration of heavy metal in soil is detrimental to soil quality. The Heigangkou-Liuyuankou irrigation area in the lower-reach of Yellow River irrigation, as home to a large population and a major site to agricultural production, is vulnerable to heavy metal pollution. This study examined soil quality in Heigangkou-Liuyuankou irrigation areas of Kaifeng, China.

Rhamnolipid influences biosorption and biodegradation of phenanthrene by phenanthrene-degrading strain Pseudomonas sp. Ph6.

Given the sub-lethal risks of synthetic surfactants, rhamnolipid is a promising class of biosurfactants with the potential to promote the bioavailability of polycyclic aromatic hydrocarbons (PAHs), to provide a favorable substitute for synthetic surfactants. However, few previous studies have integrated the behavior and mechanism behind rhamnolipid-influenced PAH biosorption and biodegradation. This is, to our knowledge, the first report of a bacterial envelope regulated link between phenanthrene (PHE) biosorption and biodegradation by rhamnolipid-induced PHE-degrading strain Pseudomonas sp.

Changes in rhizosphere bacterial gene expression following glyphosate treatment.

In commercial agriculture, populations and interactions of rhizosphere microflora are potentially affected by the use of specific agrichemicals, possibly by affecting gene expression in these organisms. To investigate this, we examined changes in bacterial gene expression within the rhizosphere of glyphosate-tolerant corn (Zea mays) and soybean (Glycine max) in response to long-term glyphosate (PowerMAX™, Monsanto Company, MO, USA) treatment. A long-term glyphosate application study was carried out using rhizoboxes under greenhouse conditions with soil previously having no history of glyphosate exposure.

Biodegradation of 3,3',4,4'-tetrachlorobiphenyl by Sinorhizobium meliloti NM.

A rhizobial strain, Sinorhizobium meliloti NM, could use 3,3',4,4'-tetrachloro-biphenyl (PCB 77) as the sole carbon and energy source for growth in mineral salt medium. The degradation efficiency of PCB 77 by strain NM and the bacterial growth increased with a decrease in PCB 77 concentration (5-0.25mgL(-1)).

Glyphosate effects on soil rhizosphere-associated bacterial communities.

Glyphosate is one of the most widely used herbicides in agriculture with predictions that 1.35 million metric tons will be used annually by 2017. With the advent of glyphosate tolerant (GT) cropping more than 10 years ago, there is now concern for non-target effects on soil microbial communities that has potential to negatively affect soil functions, plant health, and crop productivity.

Association of shifting populations in the root zone microbiome of millet with enhanced crop productivity in the Sahel region (Africa).

This study characterized specific changes in the millet root zone microbiome stimulated by long-term woody-shrub intercropping at different sites in Senegal. At the two study sites, intercropping with woody shrubs and shrub residue resulted in a significant increase in millet [Pennisetum glaucum (L.) R.

Application of organic amendments to restore degraded soil: effects on soil microbial properties.

Topsoil removal, compaction, and other practices in urban and industrial landscapes can degrade soil and soil ecosystem services. There is growing interest to remediate these for recreational and residential purposes, and urban waste materials offers potential to improve degraded soils. Therefore, the objective of this study was to compare the effects of urban waste products on microbial properties of a degraded industrial soil.

Comparison of whole-cell fatty acid (MIDI) or phospholipid fatty acid (PLFA) extractants as biomarkers to profile soil microbial communities.

The whole-cell lipid extraction to profile microbial communities on soils using fatty acid (FA) biomarkers is commonly done with the two extractants associated with the phospholipid fatty acid (PLFA) or Microbial IDentification Inc. (MIDI) methods. These extractants have very different chemistry and lipid separation procedures, but often shown a similar ability to discriminate soils from various management and vegetation systems.

Lipid profiling of the soybean pathogen Phytophthora sojae using Fatty Acid Methyl Esters (FAMEs).

Phytophthora sojae is a destructive soilborne pathogen of soybean, but currently there is no rapid or commercially available testing for its infestation level in soil. For growers, such information would greatly improve their ability to make management decisions to minimize disease damage to soybean crops. Fatty acid profiling of P.

Standardizing methylation method during phospholipid fatty acid analysis to profile soil microbial communities.

Phospholipid fatty acid (PLFA) as biomarkers, is widely used to profile microbial communities in environmental samples. However, PLFA extraction and derivatization protocols are not standardized and have widely varied among published studies. Specifically investigators have used either HCl/MeOH or KOH/MeOH or both for the methylation step of PLFA analysis, without justification or research to support either one.

Stigmasterol and cholesterol regulate the expression of elicitin genes in Phytophthora sojae.

Sterol acquisition by soilborne plant pathogens of the genus Phytophthora is presumed to involve extracellular proteins belonging to class-I elicitins. However, little is known about the relationship between sterol availability and elicitin secretion. The objective of this study was to determine the expression of class-I elicitin genes in Phytophthora sojae when grown in a medium containing stigmasterol or cholesterol.

PLFA profiling of microbial community structure and seasonal shifts in soils of a Douglas-fir chronosequence.

The impact and frequency of forest harvesting could significantly affect soil microbial community (SMC) structure and functioning. The ability of soil microorganisms to perform biogeochemical processes is critical for sustaining forest productivity and has a direct impact on decomposition dynamics and carbon storage potential. The Wind River Canopy Crane Research Forest in SW, WA, provided a unique opportunity to study a forest chronosequence and the residual effects of harvesting on the SMC in comparison to old-growth forests.

Seasonal variations in sugar contents and microbial community in a ryegrass soil.

The relationship among sugar concentrations, microbial community and physical variables (precipitation and soil temperature) was investigated in a ryegrass soil from January 2004 to January 2005. Mono- and disaccharide sugars were extracted using a mixture of dichloromethane and methanol and analyzed as their TMS derivatives by GC-MS. Changes in microbial community were assessed using phospholipid and neutral lipid fatty acids (PLFA and NLFA, respectively) analysis.

Microbial response to heavy metal-polluted soils: community analysis from phospholipid-linked fatty acids and ester-linked fatty acids extracts.

Heavy metal pollution of soil is of concern for human health and ecosystem function. The soil microbial community should be a sensitive indicator of metal contamination effects on bioavailability and biogeochemical processes. Simple methods are needed to determine the degree of in situ pollution and effectiveness of remediating metal-contaminated soils.