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1.
Disabil Rehabil ; : 1-14, 2024 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-38459897

RESUMO

PURPOSE: To identify and synthesize qualitative literature on the experiences of participants and key stakeholders in dance programs for people living with Parkinson's disease. Synthesizing the available literature can generate new insights into participant experience to inform current and future programs. MATERIALS AND METHODS: Qualitative and mixed methods studies were identified via a systematic search of six databases: CINAHL, Web of Science, Scopus, SPORTDiscus, PsycInfo, and MEDLINE. Articles were synthesized using the meta-ethnographic method developed by Noblit and Hare (1988). Key concepts across studies were related via reciprocal translation, ultimately forming a line-of-argument synthesis. RESULTS: 26 articles met the inclusion criteria. Four interrelated, overarching themes were developed: (1) dance communities provide peer support and insight into living with Parkinson's, (2) feeling safe, accepted, and included in the dance experience, (3) overcoming dance-based challenges contributes to sense of achievement, confidence, and connectedness, and (4) dance participation is an opportunity to re-imagine oneself. CONCLUSION: Participant experience is shaped by the instructor-participant relationship, the social environment of classes, and class difficulty level. In order to support participant experience, classes should be safe, supportive, and have an appropriate challenge-skill balance. These qualities facilitate creative immersion and the potential for personal and collective change.


Physical activity can improve functional ability and quality of life in people living with Parkinson's disease (PD).Dance is a safe, enjoyable form of physical activity for people with PD that creates opportunities for meaningful social engagement and artistic expression.The quality of the instructor-dancer relationship, the wider social environment, and the challenge-skill balance contribute to dancer experience.For a dance class for people with PD to be successful, it must be safe, socially accepting, and provide opportunities for dancers to experience positive growth and a sense of achievement.

2.
Sci China Life Sci ; 67(5): 1085-1086, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38324131

RESUMO

A customised synthetic microbial community (SynCom) composed of carefully selected rhizosphere-competent bacterial strains improved rice growth, yield and resistance to soil acidity and Al toxicity.


Assuntos
Oryza , Rizosfera , Microbiologia do Solo , Solo , Oryza/crescimento & desenvolvimento , Oryza/microbiologia , Oryza/metabolismo , Solo/química , Bactérias/metabolismo , Bactérias/genética , Microbiota , Concentração de Íons de Hidrogênio
3.
FEMS Microbiol Ecol ; 99(11)2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37816673

RESUMO

The root-associated soil microbiome contributes immensely to support plant health and performance against abiotic and biotic stressors. Understanding the processes that shape microbial assembly in root-associated soils is of interest in microbial ecology and plant health research. In this study, 37 plant species were grown in the same soil mixture for 10 months, whereupon the root-associated soil microbiome was assessed using amplicon sequencing. From this, the contribution of direct and indirect plant effects on microbial assembly was assessed. Plant species and plant-induced changes in soil physicochemistry were the most significant factors that accounted for bacterial and fungal community variation. Considering that all plants were grown in the same starting soil mixture, our results suggest that plants, in part, shape the assembly of their root-associated soil microbiome via their effects on soil physicochemistry. With the increase in phylogenetic ranking from plant species to class, we observed declines in the degree of community variation attributed to phylogenetic origin. That is, plant-microbe associations were unique to each plant species, but the phylogenetic associations between plant species were not important. We observed a large degree of residual variation (> 65%) not accounted for by any plant-related factors, which may be attributed to random community assembly.


Assuntos
Microbiota , Microbiologia do Solo , Filogenia , Solo , Bactérias/genética , Plantas/microbiologia , Raízes de Plantas/microbiologia , Rizosfera
4.
Mol Ecol Resour ; 2023 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-37208988

RESUMO

Phytophthora agathidicida is a virulent soil pathogen of Aotearoa New Zealand's iconic kauri tree species (Agathis australis (D. Don) Lindl.) and the primary causal agent of kauri dieback disease. To date, only a few control options are available to treat infected kauri that are expressing symptoms of dieback disease. Previous research has identified strains of Penicillium and Burkholderia that inhibited the mycelial growth of P. agathidicida in vitro. However, the mechanisms of inhibition remain unknown. By performing whole genome sequencing, we screened the genomes of four Penicillium and five Burkholderia strains to identify secondary metabolite encoding biosynthetic gene clusters (SM-BGCs) that may be implicated in the production of antimicrobial compounds. We identified various types of SM-BGCs in the genome of each strain, including polyketide synthases (PKSs), non-ribosomal peptide synthetases (NRPSs), and terpenes. Across all four of the Penicillium strains, five SM-BGCs were detected that encoded the biosynthesis of napthopyrone, clavaric acid, pyranonigrin E, dimethyl coprogen and asperlactone. Across all five of the Burkholderia strains, three SM-BGCs were detected that encoded the biosynthesis of ornibactin, pyochelin and pyrrolnitin. Our analysis detected numerous SM-BGCs which could not be characterised. Further efforts should be made to identify the compounds encoded by these SM-BGCs so that we can explore their antimicrobial potential. The potential inhibitory effects of the compounds encoded by the SM-BGCs identified in this study may be worthy of further investigation for their effect on the growth and virulence of P. agathidicida.

5.
Microbiol Spectr ; : e0036423, 2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-36951587

RESUMO

Secretion of exoproteins is a key component of bacterial virulence, and is tightly regulated in response to environmental stimuli and host-dependent signals. The entomopathogenic bacterium Yersinia entomophaga MH96 produces a wide range of exoproteins including its main virulence factor, the 2.46 MDa insecticidal Yen-Tc toxin complex. Previously, a high-throughput transposon-based screening assay identified the region of exoprotein release (YeRER) as essential to exoprotein release in MH96. This study defines the role of the YeRER associated ambiguous holin/endolysin-based lysis cluster (ALC) and the novel RoeA regulator in the regulation and release of exoproteins in MH96. A mutation in the ambiguous lysis cassette (ALC) region abolished exoprotein release and caused cell elongation, a phenotype able to be restored through trans-complementation with an intact ALC region. Endogenous ALC did not impact cell growth of the wild type, while artificial expression of an optimized ALC caused cell lysis. Using HolA-sfGFP and Rz1-sfGFP reporters, Rz1 expression was observed in all cells while HolA expression was limited to a small proportion of cells, which increased over time. Transcriptomic assessments found expression of the genes encoding the prominent exoproteins, including the Yen-Tc, was reduced in the roeA mutant and identified a 220 ncRNA of the YeRER intergenic region that, when trans complemented in the wildtype, abolished exoprotein release. A model for Y. entomophaga mediated exoprotein regulation and release is proposed. IMPORTANCE While theoretical models exist, there is not yet any empirical data that links ALC phage-like lysis cassettes with the release of large macro-molecular toxin complexes, such as Yen-Tc in Gram-negative bacteria. In this study, we demonstrate that the novel Y. entomophaga RoeA activates the production of exoproteins (including Yen-Tc) and the ALC at the transcriptional level. The translation of the ALC holin is confined to a subpopulation of cells that then lyse over time, indicative of a complex hierarchical regulatory network. The presence of an orthologous RoeA and a HolA like holin 5' of an eCIS Afp element in Pseudomonas chlororaphis, combined with the presented data, suggests a shared mechanism is required for the release of some large macromolecular protein assemblies, such as the Yen-Tc, and further supports classification of phage-like lysis clusters as type 10 secretion systems.

6.
PLoS One ; 17(1): e0263019, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35077520

RESUMO

Bacterial protein secretion is crucial to the maintenance of viability and pathogenicity. Although many bacterial secretion systems have been identified, the underlying mechanisms regulating their expression are less well explored. Yersinia entomophaga MH96, an entomopathogenic bacterium, releases an abundance of proteins including the Yen-Tc into the growth medium when cultured in Luria Bertani broth at ≤ 25°C. Through the development of a high-throughput exoproteome screening assay (HESA), genes involved in MH96 exoprotein production were identified. Of 4,080 screened transposon mutants, 34 mutants exhibited a decreased exoprotein release, and one mutation located in the intergenic region of the Yen-Tc operon displayed an elevated exoprotein release relative to the wild-type strain MH96. DNA sequencing revealed several transposon insertions clustered in gene regions associated with lipopolysaccharide (LPSI and LPSII), and N-acyl-homoserine lactone synthesis (quorum sensing). Twelve transposon insertions were located within transcriptional regulators or intergenic regions. The HESA will have broad applicability for identifying genes associated with exoproteome production in a range of microorganisms.


Assuntos
Proteínas de Bactérias , Regulação Bacteriana da Expressão Gênica , Proteoma , Yersinia , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Proteoma/genética , Proteoma/metabolismo , Yersinia/genética , Yersinia/metabolismo
7.
G3 (Bethesda) ; 11(1)2021 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-33561230

RESUMO

The function of microbes can be inferred from knowledge of genes specifically expressed in natural environments. Here, we report the in vivo transcriptome of the entomopathogenic bacterium Yersinia entomophaga MH96, captured during initial, septicemic, and pre-cadaveric stages of intrahemocoelic infection in Galleria mellonella. A total of 1285 genes were significantly upregulated by MH96 during infection; 829 genes responded to in vivo conditions during at least one stage of infection, 289 responded during two stages of infection, and 167 transcripts responded throughout all three stages of infection compared to in vitro conditions at equivalent cell densities. Genes upregulated during the earliest infection stage included components of the insecticidal toxin complex Yen-TC (chi1, chi2, and yenC1), genes for rearrangement hotspot element containing protein yenC3, cytolethal distending toxin cdtAB, and vegetative insecticidal toxin vip2. Genes more highly expressed throughout the infection cycle included the putative heat-stable enterotoxin yenT and three adhesins (usher-chaperone fimbria, filamentous hemagglutinin, and an AidA-like secreted adhesin). Clustering and functional enrichment of gene expression data also revealed expression of genes encoding type III and VI secretion system-associated effectors. Together these data provide insight into the pathobiology of MH96 and serve as an important resource supporting efforts to identify novel insecticidal agents.


Assuntos
Mariposas , Fatores de Virulência , Animais , Perfilação da Expressão Gênica , Humanos , Yersinia/genética
8.
FEMS Microbiol Ecol ; 96(5)2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32179899

RESUMO

Globally, the conversion of primary forests to plantations and agricultural landscapes is a common land use change. Kauri (Agathis australis) is one of the most heavily impacted indigenous tree species of New Zealand with <1% of primary forest remaining as fragments adjacent to pastoral farming and exotic forest plantations. By contrasting two forest systems, we investigated if the fragmentation of kauri forests and introduction of pine plantations (Pinus radiata) are significantly impacting the diversity and composition of soil microbial communities across Waipoua kauri forest, New Zealand. Using next generation based 16S rRNA and ITS gene region sequencing, we identified that fungal and bacterial community composition significantly differed between kauri and pine forest soils. However, fungal communities displayed the largest differences in diversity and composition. This research revealed significant shifts in the soil microbial communities surrounding remnant kauri fragments, including the loss of microbial taxa with functions in disease suppression and plant health. Kauri dieback disease, caused by Phytophthora agathidicida, currently threatens the kauri forest ecosystem. Results from this research highlight the need for further investigations into how changes to soil microbial diversity surrounding remnant kauri fragments impact tree health and disease expression.


Assuntos
Pinus , Ecossistema , Florestas , Nova Zelândia , RNA Ribossômico 16S/genética , Solo , Microbiologia do Solo
9.
J Invertebr Pathol ; 165: 82-88, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-29196233

RESUMO

Biopesticides are needed for control of endemic and invasive pests impacting New Zealand's primary sectors including pests that are emerging as a result of climate change and farming intensification. Products developed in New Zealand are usually based on endemic strains of microorganisms, including new species/strains with novel modes of action. For example, Invade and BioShield were developed using endemic strains of the bacterium Serratia entomophila, for use in New Zealand only. To date, most of these home-grown products have either struggled for market share or have remained in small niche markets. However, the number of products registered for use has been steadily increasing in response to consumer demand. Factors limiting past use of biopesticides in New Zealand include market size, registration costs and limited efficacy over a range of climatic zones. Many promising new agents are currently under development as biopesticides with international applications and the launch of several new start-up companies suggests a brighter future for biopesticide use in New Zealand.


Assuntos
Agentes de Controle Biológico , Controle de Insetos , Controle Biológico de Vetores , Animais , Bacillus , Bacillus thuringiensis , Bactérias , Baculoviridae , Beauveria , Brevibacillus , Granulovirus , Hypocreales , Controle de Insetos/métodos , Controle de Insetos/tendências , Insetos/microbiologia , Insetos/parasitologia , Marketing/tendências , Nova Zelândia , Controle Biológico de Vetores/métodos , Controle Biológico de Vetores/tendências , Rabditídios , Serratia , Yersinia
10.
PLoS One ; 13(5): e0196581, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29734390

RESUMO

Cropping soils vary in extent of natural suppression of soil-borne plant diseases. However, it is unknown whether similar variation occurs across pastoral agricultural systems. We examined soil microbial community properties known to be associated with disease suppression across 50 pastoral fields varying in management intensity. The composition and abundance of the disease-suppressive community were assessed from both taxonomic and functional perspectives. Pseudomonas bacteria were selected as a general taxonomic indicator of disease suppressive potential, while genes associated with the biosynthesis of a suite of secondary metabolites provided functional markers (GeoChip 5.0 microarray analysis). The composition of both the Pseudomonas communities and disease suppressive functional genes were responsive to land use. Underlying soil properties explained 37% of the variation in Pseudomonas community structure and up to 61% of the variation in the abundance of disease suppressive functional genes. Notably, measures of soil organic matter quality, C:P ratio, and aromaticity of the dissolved organic matter content (carbon recalcitrance), influenced both the taxonomic and functional disease suppressive potential of the pasture soils. Our results suggest that key components of the soil microbial community may be managed on-farm to enhance disease suppression and plant productivity.


Assuntos
Microbiologia Ambiental , Microbiologia do Solo , Solo/química , Agricultura/métodos , Carbono/análise , Resistência à Doença , Ecossistema , Microbiota , Nova Zelândia , Nitrogênio/análise , Pseudomonas
11.
PLoS One ; 13(2): e0192607, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29489845

RESUMO

Biological nitrogen fixation through the legume-rhizobia symbiosis is important for sustainable pastoral production. In New Zealand, the most widespread and valuable symbiosis occurs between white clover (Trifolium repens L.) and Rhizobium leguminosarum bv. trifolii (Rlt). As variation in the population size (determined by most probable number assays; MPN) and effectiveness of N-fixation (symbiotic potential; SP) of Rlt in soils may affect white clover performance, the extent in variation in these properties was examined at three different spatial scales: (1) From 26 sites across New Zealand, (2) at farm-wide scale, and (3) within single fields. Overall, Rlt populations ranged from 95 to >1 x 108 per g soil, with variation similar at the three spatial scales assessed. For almost all samples, there was no relationship between rhizobia population size and ability of the population to fix N during legume symbiosis (SP). When compared with the commercial inoculant strain, the SP of soils ranged between 14 to 143% efficacy. The N-fixing ability of rhizobia populations varied more between samples collected from within a single hill country field (0.8 ha) than between 26 samples collected from diverse locations across New Zealand. Correlations between SP and calcium and aluminium content were found in all sites, except within a dairy farm field. Given the general lack of association between SP and MPN, and high spatial variability of SP at single field scale, provision of advice for treating legume seed with rhizobia based on field-average MPN counts needs to be carefully considered.


Assuntos
Medicago/microbiologia , Rhizobium leguminosarum/fisiologia , Simbiose , Nova Zelândia , Microbiologia do Solo
12.
Genome Announc ; 5(22)2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28572330

RESUMO

Paraburkholderia sp. strain A27, isolated from the root material of white clover, has plant growth-promoting activity on a range of agriculturally important plants. The draft genome of this bacterium is 7,393,089 bp and harbors a range of genes putatively involved in host colonization.

13.
Genome Announc ; 5(15)2017 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-28408678

RESUMO

Pseudomonas sp. strain C9 is a plant growth-promoting bacterium isolated from the root tissue of Brassica oleracea L. grown in soil from Marlborough, New Zealand. Its draft genome of 6,350,161 bp contains genes associated with plant growth promotion and biological control.

14.
Appl Microbiol Biotechnol ; 100(13): 5729-46, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27188775

RESUMO

There is increasing interest in the use of beneficial microorganisms as alternatives to chemical pesticides and synthetic fertilisers in agricultural production. Application of beneficial microorganisms to seeds is an efficient mechanism for placement of microbial inocula into soil where they will be well positioned to colonise seedling roots and protect against soil-borne diseases and pests. However, despite the long history of inoculation of legume seeds with Rhizobia spp. and clear laboratory demonstration of the ability of a wide range of other beneficial microorganisms to improve crop performance, there are still very few commercially available microbial seed inoculants. Seed inoculation techniques used for research purposes are often not feasible at a commercial scale and there are significant technical challenges in maintaining viable microbial inocula on seed throughout commercial seed treatment processes and storage. Further research is needed before the benefits of a wide range of environmentally sensitive potential seed inoculants can be captured for use in agriculture, ecosystem restoration and bioremediation. There is no single solution to the challenge of improving the ability of seed inoculants to establish and function consistently in the field. Development of novel formulations that maintain the viability of both inoculant and seed during storage will result from multidisciplinary research in microbial and seed physiology and adjuvant chemistry.


Assuntos
Inoculantes Agrícolas/crescimento & desenvolvimento , Agricultura/métodos , Produtos Agrícolas/microbiologia , Doenças das Plantas/prevenção & controle , Sementes/microbiologia , Agricultura/tendências , Produtos Agrícolas/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Sementes/crescimento & desenvolvimento
15.
Stand Genomic Sci ; 10: 121, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26649149

RESUMO

Rhizobium leguminosarum bv. trifolii strain CC275e is a highly effective, N2-fixing microsymbiont of white clover (Trifolium repens L.). The bacterium has been widely used in both Australia and New Zealand as a clover seed inoculant and, as such, has delivered the equivalent of millions of dollars of nitrogen into these pastoral systems. R. leguminosarum strain CC275e is a rod-shaped, motile, Gram-negative, non-spore forming bacterium. The genome was sequenced on an Illumina MiSeq instrument using a 2 × 150 bp paired end library and assembled into 29 scaffolds. The genome size is 7,077,367 nucleotides, with a GC content of 60.9 %. The final, high-quality draft genome contains 6693 protein coding genes, close to 85 % of which were assigned to COG categories. This Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession JRXL00000000. The sequencing of this genome will enable identification of genetic traits associated with host compatibility and high N2 fixation characteristics in Rhizobium leguminosarum. The sequence will also be useful for development of strain-specific markers to assess factors associated with environmental fitness, competiveness for host nodule occupancy, and survival on legume seeds (New Zealand Ministry of Business, Innovation and Employment program, 'Improving forage legume-rhizobia performance' contract C10X1308 and DairyNZ Ltd.).

16.
Environ Microbiol Rep ; 7(6): 918-28, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26256849

RESUMO

The bacterium Burkholderia sp. Ha185 readily solubilizes inorganic phosphate by releasing the low molecular weight organic anion, 2-ketogluconate. Using random transposon mutagenesis and in silico analysis, a mutation that caused almost complete abolition of phosphate solubilization was located within hemX, which is part of the hem operon. Burkholderia sp. Ha185 HemX is a multidomain protein, predicted to encode a bifunctional uroporphyrinogen-III synthetase/uroporphyrin-III C-methyltransferase, which has not previously been implicated in phosphate solubilization. Complementation of hemX restored the ability of the mutant to solubilize phosphate in both plate and liquid cultures. Based on a combination of organic-anion profiling, quantitative polymerase chain reaction and in silico analyses, hemX was confirmed to be solely responsible for hydroxyapatite solubilization in Burkholderia sp. Ha185. It is proposed that the biosynthesis of a yet to be determined redox cofactor by HemX is the main pathway for generating 2-ketogluconate via a haem-dependent gluconate 2-dehydrogenase in Burkholderia sp. Ha185.


Assuntos
Burkholderia/genética , Burkholderia/metabolismo , Gluconatos/metabolismo , Fosfatos/metabolismo , Desidrogenases de Carboidrato , Regulação Bacteriana da Expressão Gênica , Ordem dos Genes , Hidroximetilbilano Sintase/genética , Redes e Vias Metabólicas , Modelos Biológicos , Mutação , Óperon , Fosfatos/química , Solubilidade
17.
Glob Chang Biol ; 21(8): 2844-60, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25891785

RESUMO

Future human well-being under climate change depends on the ongoing delivery of food, fibre and wood from the land-based primary sector. The ability to deliver these provisioning services depends on soil-based ecosystem services (e.g. carbon, nutrient and water cycling and storage), yet we lack an in-depth understanding of the likely response of soil-based ecosystem services to climate change. We review the current knowledge on this topic for temperate ecosystems, focusing on mechanisms that are likely to underpin differences in climate change responses between four primary sector systems: cropping, intensive grazing, extensive grazing and plantation forestry. We then illustrate how our findings can be applied to assess service delivery under climate change in a specific region, using New Zealand as an example system. Differences in the climate change responses of carbon and nutrient-related services between systems will largely be driven by whether they are reliant on externally added or internally cycled nutrients, the extent to which plant communities could influence responses, and variation in vulnerability to erosion. The ability of soils to regulate water under climate change will mostly be driven by changes in rainfall, but can be influenced by different primary sector systems' vulnerability to soil water repellency and differences in evapotranspiration rates. These changes in regulating services resulted in different potentials for increased biomass production across systems, with intensively managed systems being the most likely to benefit from climate change. Quantitative prediction of net effects of climate change on soil ecosystem services remains a challenge, in part due to knowledge gaps, but also due to the complex interactions between different aspects of climate change. Despite this challenge, it is critical to gain the information required to make such predictions as robust as possible given the fundamental role of soils in supporting human well-being.


Assuntos
Mudança Climática , Solo , Ecossistema , Nova Zelândia
18.
Environ Pollut ; 190: 1-9, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24686114

RESUMO

Pollution induced community tolerance (PICT) to Cu(2+), and co-tolerance to nanoparticulate Cu, ionic silver (Ag(+)), and vancomycin were measured in field soils treated with Cu(2+) 15 years previously. EC50 values were determined using substrate induced respiration and correlations made against soil physicochemical properties, microbial community structure, physiological status (qCO2; metabolic quotient), and abundances of genes associated with metal and antibiotic resistance. Previous level of exposure to copper was directly (P < 0.05) associated with tolerance to addition of new Cu(2+), and also of nanoparticle Cu. However, Cu-exposed communities had no co-tolerance to Ag(+) and had increased susceptibly to vancomycin. Increased tolerance to both Cu correlated (P < 0.05) with increased metabolic quotient, potentially indicating that the community directed more energy towards cellular maintenance rather than biomass production. Neither bacterial or fungal community composition nor changes in the abundance of genes involved with metal resistance were related to PICT or co-tolerance mechanisms.


Assuntos
Cobre/toxicidade , Microbiologia do Solo , Poluentes do Solo/toxicidade , Adaptação Fisiológica , Biomassa , Cobre/análise , Cobre/metabolismo , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/metabolismo
19.
FEMS Microbiol Ecol ; 88(3): 538-49, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24646185

RESUMO

Sulphur-oxidising bacteria (SOB) play a key role in the biogeochemical cycling of sulphur in soil ecosystems. However, the ecology of SOB is poorly understood, and there is little knowledge about the taxa capable of sulphur oxidation, their distribution, habitat preferences and ecophysiology. Furthermore, as yet there are no conclusive links between SOB community size or structure and rates of sulphur oxidation. We have developed a molecular approach based on primer design targeting the soxB functional gene of nonfilamentous chemolithotrophic SOB that allows assessment of both abundance and diversity. Cloning and sequencing revealed considerable diversity of known soxB genotypes from agricultural soils and also evidence for previously undescribed taxa. In a microcosm experiment, abundance of soxB genes increased with sulphur oxidation rate in soils amended with elemental sulphur. Addition of elemental sulphur to soil had a significant effect in the soxB gene diversity, with the chemolithotrophic Thiobacillus-like Betaproteobacteria sequences dominating clone libraries 6 days after sulphur application. Using culture-independent methodology, the study provides evidence for links between abundance and diversity of SOB and sulphur oxidation. The methodology provides a new tool for investigation of the ecology and role of SOB in soil sulphur biogeochemistry.


Assuntos
Bactérias/classificação , Microbiologia do Solo , Enxofre/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Betaproteobacteria/genética , Biodiversidade , Primers do DNA , Ecossistema , Genes Bacterianos , Dados de Sequência Molecular , Oxirredução , Filogenia , Reação em Cadeia da Polimerase
20.
Environ Pollut ; 179: 177-84, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23685630

RESUMO

MicroResp™ is a miniaturised method for measuring substrate induced respiration (SIR) in soil. We modified the MicroResp™ method to develop a rapid tool for quantifying the ecotoxicological impact of contaminants. The method is based on reduction in SIR across a gradient of contaminant, allowing for determination of dose-response curves EC-values. Contaminants are mixed into soil samples at a range of concentrations; each sample is then dispensed into a column of eight wells in 96 well format (deep) plates. Moisture and glucose are added to the samples at levels to provide maximum response. Released CO2 from the soils is then measured using colorimetric gel-traps, following the standard MicroResp™ methodology. Examination revealed that this method works over a range of soil types and is insensitive to minor variations in assay length (2-7 h), alteration of moisture content (±20 µL from optimum), and soil storage conditions (4 °C versus fresh).


Assuntos
Fenômenos Ecológicos e Ambientais , Monitoramento Ambiental/métodos , Microbiologia do Solo , Poluentes do Solo/toxicidade , Bioensaio , Ecotoxicologia , Solo/química
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