Dissolved organic matter characteristics linked to bacterial community succession and nitrogen removal performance in woodchip bioreactors.

Woodchip bioreactors are an eco-friendly technology for removing nitrogen (N) pollution. However, there needs to be more clarity regarding the dissolved organic matter (DOM) characteristics and bacterial community succession mechanisms and their association with the N removal performance of bioreactors. The laboratory woodchip bioreactors were continuously operated for 360 days under three influent N level treatments, and the results showed that the average removal rate of TN was 45.

Regulatory roles of the second messenger c-di-GMP in beneficial plant-bacteria interactions.

The rhizosphere system of plants hosts a diverse consortium of bacteria that confer beneficial effects on plant, such as plant growth-promoting rhizobacteria (PGPR), biocontrol agents with disease-suppression activities, and symbiotic nitrogen fixing bacteria with the formation of root nodule. Efficient colonization in planta is of fundamental importance for promoting of these beneficial activities. However, the process of root colonization is complex, consisting of multiple stages, including chemotaxis, adhesion, aggregation, and biofilm formation.

The volatile organic compound acetoin enhances the colonization of Azorhizobium caulinodans ORS571 on Sesbania rostrata.

Chemoreceptors play a crucial role in assisting bacterial sensing and response to environmental stimuli. Genome analysis of Azorhizobium caulinodans ORS571 revealed the presence of 43 putative chemoreceptors, but their biological functions remain largely unknown. In this study, we identified the chemoreceptor AmaP (methyl-accepting protein of A.

Bioaugmentation of woodchip bioreactors by Pseudomonas nicosulfuronedens D1-1 with functional species enrichment.

A novel heterotrophic nitrification and aerobic denitrification (HN-AD) bacterium D1-1 was identified as Pseudomonas nicosulfuronedens D1-1. Strain D1-1 removed 97.24%, 97.

Transcriptomic Identification of a Unique Set of Nodule-Specific Cysteine-Rich Peptides Expressed in the Nitrogen-Fixing Root Nodule of .

Legumes in the inverted repeat-lacking clade (IRLC) each produce a unique set of nodule-specific cysteine-rich (NCR) peptides, which act in concert to determine the terminal differentiation of nitrogen-fixing bacteroid. IRLC legumes differ greatly in their numbers of NCR and sequence diversity. This raises the significant question how bacteroid differentiation is collectively controlled by the specific NCR repertoire of an IRLC legume.

Role of a local transcription factor in governing cellular carbon/nitrogen homeostasis in Pseudomonas fluorescens.

Autoactivation of two-component systems (TCSs) can increase the sensitivity to signals but inherently cause a delayed response. Here, we describe a unique negative feedback mechanism enabling the global NtrB/NtrC regulator to rapidly respond to nitrogen starvation over the course of histidine utilization (hut) in Pseudomonas fluorescens. NtrBC directly activates transcription of hut genes, but overexpression will produce excess ammonium leading to NtrBC inactivation.

Plant transcriptome analysis reveals specific molecular interactions between alfalfa and its rhizobial symbionts below the species level.

Background: Leguminous plants alter patterns of gene expression in response to symbiotic colonization and infection by their cognate rhizobial bacteria, but the extent of the transcriptomic response has rarely been examined below the species level. Here we describe the identification of 12 rhizobial biotypes of Ensifer meliloti, which form nitrogen-fixing nodules in the roots of alfalfa (Medicago sativa L.), followed by a comparative RNA-seq analysis of four alfalfa cultivars each inoculated with two E.

Global Regulatory Roles of the Histidine-Responsive Transcriptional Repressor HutC in Pseudomonas fluorescens SBW25.

HutC is known as a transcriptional repressor specific for histidine utilization () genes in Gram-negative bacteria, including SBW25. However, its precise mode of protein-DNA interactions hasn't been examined with purified HutC proteins. Here, we performed electrophoretic mobility shift assay (EMSA) and DNase I footprinting using His-tagged HutC and biotin-labeled probe of the promoter (P).

NfiR, a New Regulatory Noncoding RNA (ncRNA), Is Required in Concert with the NfiS ncRNA for Optimal Expression of Nitrogenase Genes in Pseudomonas stutzeri A1501.

Expression of nitrogenase genes () is strictly regulated at both transcriptional and posttranscriptional levels. Efficient nitrogenase activity requires maintaining sufficient levels of mRNAs, yet the underlying mechanism is not fully understood due to its complexity. We have previously shown that a novel regulatory noncoding RNA (ncRNA), NfiS, optimizes nitrogen fixation through targeting mRNA in A1501.

Repeated Phenotypic Evolution by Different Genetic Routes in Pseudomonas fluorescens SBW25.

Repeated evolution of functionally similar phenotypes is observed throughout the tree of life. The extent to which the underlying genetics are conserved remains an area of considerable interest. Previously, we reported the evolution of colony switching in two independent lineages of Pseudomonas fluorescens SBW25.

Predicting mutational routes to new adaptive phenotypes.

Predicting evolutionary change poses numerous challenges. Here we take advantage of the model bacterium in which the genotype-to-phenotype map determining evolution of the adaptive 'wrinkly spreader' (WS) type is known. We present mathematical descriptions of three necessary regulatory pathways and use these to predict both the rate at which each mutational route is used and the expected mutational targets.

Transcriptional and Post-Translational Targeting of Myocyte Stress Protein 1 (MS1) by the JNK Pathway in Cardiac Myocytes.

Myocyte Stress Protein 1 (MS1) is a muscle-specific, stress-responsive, regulator of gene expression. It was originally identified in embryonic mouse heart which showed increased expression in a rat model of left ventricular hypertrophy. To determine if MS1 was responsive to other stresses relevant to cardiac myocyte function, we tested if it could be induced by the metabolic stresses associated with ischaemia/reperfusion injury in cardiac myocytes.

Identification and Characterization of Domesticated Bacterial Transposases.

Selfish genetic elements, such as insertion sequences and transposons are found in most genomes. Transposons are usually identifiable by their high copy number within genomes. In contrast, REP-associated tyrosine transposases (RAYTs), a recently described class of bacterial transposase, are typically present at just one copy per genome.

Nematode grazing promotes bacterial community dynamics in soil at the aggregate level.

Nematode predation has important roles in determining bacterial community composition and dynamics, but the extent of the effects remains largely rudimentary, particularly in natural environment settings. Here, we investigated the complex microbial-microfaunal interactions in the rhizosphere of maize grown in red soils, which were derived from four long-term fertilization regimes. Root-free rhizosphere soil samples were separated into three aggregate fractions whereby the abundance and community composition were examined for nematode and total bacterial communities.

Unravelling the complexity and redundancy of carbon catabolic repression in Pseudomonas fluorescens SBW25.

The two-component system CbrAB is the principal regulator for cellular metabolic balance in Pseudomonas fluorescens SBW25 and is necessary for growth on many substrates including xylose. To understand the regulatory linkage between CbrAB and genes for xylose utilization (xut), we performed transposon mutagenesis of ΔcbrB to select for Xut suppressors. This led to identification of crc and hfq.

Evolutionary convergence in experimental Pseudomonas populations.

Model microbial systems provide opportunity to understand the genetic bases of ecological traits, their evolution, regulation and fitness contributions. Experimental populations of Pseudomonas fluorescens rapidly diverge in spatially structured microcosms producing a range of surface-colonising forms. Despite divergent molecular routes, wrinkly spreader (WS) niche specialist types overproduce a cellulosic polymer allowing mat formation at the air-liquid interface and access to oxygen.

Modes of migration and multilevel selection in evolutionary multiplayer games.

The evolution of cooperation in group-structured populations has received much attention, but little is known about the effects of different modes of migration of individuals between groups. Here, we have incorporated four different modes of migration that differ in the degree of coordination among the individuals. For each mode of migration, we identify the set of multiplayer games in which the cooperative strategy has higher fixation probability than defection.

Mini-Tn7 vectors for studying post-transcriptional gene expression in Pseudomonas.

We describe the construction and validation of five mini-Tn7 vectors for analysis of post-transcriptional gene expression in Pseudomonas. Four vectors allow construction of translational fusions to β-galactosidase (lacZ), while the fifth is designed for functional analysis of noncoding RNA genes. Translational fusions can be constructed without a functional promoter in the vector or from an inducible promoter of either P(tac) or P(dctA).

Modeling the effect of insulin-like growth factor-1 on human cell growth.

Insulin-like growth factor-1 (IGF-1) plays a key role in human growth and development. The interactions of IGF-1 with IGF-1 receptors and IGF-1 binding proteins (IGFBPs) regulate IGF-1 function. Recent research suggests that a metabolite of IGF-1, cyclo-glycyl-proline (cGP), has a role in regulating IGF-1 homeostasis.

4-tert-Butyl-pyridinium chloride-4,4'-(propane-2,2-di-yl)bis-(2,6-di-methyl-phenol)-toluene (2/2/1).

In the title solvated salt, C9H14N(+)·Cl(-)·C19H24O2·0.5C7H7, two mol-ecules of 4,4'-(propane-2,2-di-yl)bis-(2,6-di-methyl-phenol) are linked via O-H⋯Cl hydrogen bonds to two chloride ions, each of which is also engaged in N-H⋯Cl hydrogen bonding to a 4-tert-butyl-pyridinium cation, giving a cyclic hydrogen-bonded entity centred at 1/2, 1/2, 1/2. The toluene solvent mol-ecule resides in the lattice and resides on an inversion centre; the disorder of the methyl group requires it to have a site-occupancy factor of 0.

A long-term field experiment of soil transplantation demonstrating the role of contemporary geographic separation in shaping soil microbial community structure.

The spatial patterns of microbial communities are largely determined by the combined effects of historical contingencies and contemporary environmental disturbances, but their relative importance remains poorly understood. Empirical biogeographic data currently available are mostly based on the traditional method of observational survey, which typically involves comparing indigenous microbial communities across spatial scales. Here, we report a long-term soil transplantation experiment, whereby the same two soils (red Acrisol and purple Cambisol from Yingtan) were placed into two geographic locations of ∼1000 km apart (i.

Bis(μ-2-hy-droxy-methyl-2-methyl-propane-1,3-diolato)bis-[di-chlorido-titanium(IV)] diethyl ether disolvate.

The title complex, [Ti2Cl4{CH3C(CH2O)2(CH2OH)}2], lies across a centre of symmetry with a diethyl ether solvent mol-ecule hydrogen bonded to the -CH2OH groups on either side of it. The Ti(IV) atom is coordinated in a distorted octa-hedral geometry by a tripodal ligand and two terminal chloride atoms. There are three coordination modes for the tripodal ligand distinguishable on the basis of their very different Ti-O bond lengths.

[6,6'-Bis(1,1-di-methyl-eth-yl)-4,4'-dimethyl-2,2'-methyl-enediphenolato-κ(2) O,O']di-chlorido-(9H-fluoren-9-ol-κO)titanium(IV)-fluorene-diethyl ether (1/0.5/1).

The title adduct, [TiCl2(C23H30O2)(C13H10O]·0.5C13H10·C4H10O, is a monomer with a trigonal-bypyramidal coordination sphere of the Ti(IV) atom in which the ligand O atoms of the bidentate diphenolate anion are located in both apical and equatorial positions. Chloride ligands occupy the remaining two equatorial sites of the trigonal bypyramid with the fluoren-9-ol O atom occupying the other apical site.

Urocanate as a potential signaling molecule for bacterial recognition of eukaryotic hosts.

Host recognition is the crucial first step in infectious disease pathogenesis. Recognition allows pathogenic bacteria to identify suitable niches and deploy appropriate phenotypes for successful colonization and immune evasion. However, the mechanisms underlying host recognition remain largely unknown.