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1.
Anaesthesia ; 78(2): 197-206, 2023 02.
Article in English | MEDLINE | ID: mdl-36314294

ABSTRACT

The COVID-19 pandemic has imposed substantial burdens on clinicians and there is a need to better understand the impact on mental health and well-being. This scoping review investigates the prevalence of mental health concerns in anaesthetists, risk and protective factors for mental well-being, and anaesthetists' pandemic-related concerns and support. We searched online databases for articles published between January 2020 and May 2022, using search terms related to: anaesthesia; burnout, well-being, mental health or stress; and COVID-19. We identified 20 articles comprising 19 different populations of anaesthetists (n = 8680) from 14 countries. Studies identified the prevalence of the following condition in anaesthetists: burnout (14-59%); stress (50-71%); anxiety (11-74%); depression (12-67%); post-traumatic stress (17-25%); psychological distress (52%); and insomnia (17-61%). Significant risk factors for poorer mental health included: direct COVID-19-related issues (fear of self and family exposure to infection; requirement for quarantine); practitioner health factors (insomnia; comorbidities); psychosocial factors (loneliness; isolation; perceived lack of support at home and work); demographic factors (female gender; non-white ethnicity; LGBTQIA+); and workplace factors (redeployment outside area of clinical practice; increased work effort; personal protective equipment shortages). Protective factors identified included: job satisfaction; perceived organisational justice; older age; and male sex. Anaesthetists' self-reported concerns related to: personal protective equipment; resource allocation; fear of infection; fear of financial loss; increased workload; and effective communication of protocols for patient treatment. Support from family, colleagues and hospital management was identified as an important coping mechanism. Findings from this review may support the design of interventions to enhance anaesthetists' psychological health during pandemic conditions and beyond. Future research should include consistent psychological outcome measures and rigorous experimental design beyond cross-sectional studies.


Subject(s)
Burnout, Professional , COVID-19 , Sleep Initiation and Maintenance Disorders , Male , Female , Humans , COVID-19/epidemiology , Mental Health , Pandemics , SARS-CoV-2 , Sleep Initiation and Maintenance Disorders/epidemiology , Cross-Sectional Studies , Depression/psychology , Anxiety/epidemiology , Anxiety/psychology , Burnout, Professional/epidemiology , Anesthetists
2.
BMC Neurol ; 21(1): 112, 2021 Mar 11.
Article in English | MEDLINE | ID: mdl-33706706

ABSTRACT

BACKGROUND: The retinal and cerebral microvasculature share similar embryological origins and physiological characteristics. Improved imaging technologies provide opportunistic non-invasive assessment of retinal microvascular parameters (RMPs) against cognitive outcomes. We evaluated baseline measures for associations between RMPs and mild cognitive impairment (MCI) from participants of the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA). METHODS: RMPs (central retinal arteriolar / venular equivalents, arteriole to venular ratio, fractal dimension and tortuosity) were measured from optic disc centred fundus images and analysed using semi-automated software. Associations between RMPs and MCI were assessed by multivariable logistic regression with adjustment for potential confounders including age, sex, alcohol consumption, smoking status, educational attainment, physical activity, cardiovascular disease (CVD), hypertension, mean arterial blood pressure, triglycerides, diabetes, body mass index, and high density lipoprotein levels. P < 0.05 was considered statistically significant. RESULTS: Data were available for 1431 participants, of which 156 (10.9%) were classified with MCI defined by a Montreal Cognitive Assessment (MoCA) score ≤ 26, with subjective cognitive decline, in the absence of depression or problems with activities of daily living. Participants had a mean age of 62.4 ± 8.5 yrs. and 52% were female. As expected, individuals with MCI had a lower MoCA score than those without (23.5 ± 2.6 versus 26.3 ± 2.7, respectively), were more likely to be female, have a lower level of educational attainment, be less physically active, more likely to have CVD, have higher levels of triglycerides and lower levels of high density lipoprotein. No significant associations between RMPs and MCI were detected in unadjusted, minimally adjusted or fully adjusted regression models or subsequent sensitivity analyses. CONCLUSION: Previous studies have reported both increased retinal venular calibre and reduced fractal dimension in association with mild cognitive impairment. Our study failed to detect any associations between RMPs and those individuals at an early stage of cognitive loss in an older community-based cohort.


Subject(s)
Cognitive Dysfunction/diagnostic imaging , Retinal Vessels/diagnostic imaging , Retinal Vessels/pathology , Aged , Aging/pathology , Cognitive Dysfunction/complications , Cohort Studies , Female , Humans , Image Interpretation, Computer-Assisted , Longitudinal Studies , Male , Microvessels/diagnostic imaging , Microvessels/pathology , Middle Aged , Northern Ireland , Retina/diagnostic imaging , Retina/pathology
4.
Br J Anaesth ; 119(6): 1224-1230, 2017 Dec 01.
Article in English | MEDLINE | ID: mdl-29045578

ABSTRACT

Background: Anaesthetists monitor auditory information about a patient's vital signs in an environment that can be noisy and while performing other cognitively demanding tasks. It can be difficult to identify oxygen saturation (SpO2) values using existing pulse oximeter auditory displays (sonifications). Methods: In a laboratory setting, we compared the ability of non-clinician participants to detect transitions into and out of an SpO2 target range using five different sonifications while they performed a secondary distractor arithmetic task in the presence of background noise. The control sonification was based on the auditory display of current pulse oximeters and comprised a variable pitch with an alarm. The four experimental conditions included an Alarm Only condition, a Variable pitch only condition, and two conditions using sonifications enhanced with additional sound dimensions. Accuracy to detect SpO2 target transitions was the primary outcome. Results: We found that participants using the two sonifications enhanced with the additional sound dimensions of tremolo and brightness were significantly more accurate (83 and 96%, respectively) at detecting transitions to and from a target SpO2 range than participants using a pitch only sonification plus alarms (57%) as implemented in current pulse oximeters. Conclusions: Enhanced sonifications are more informative than conventional sonification. The implication is that they might allow anaesthetists to judge better when desaturation decreases below, or returns to, a target range.


Subject(s)
Auditory Perception , Clinical Alarms , Oximetry/instrumentation , Oximetry/methods , Oxygen/metabolism , Adolescent , Adult , Female , Humans , Male , Middle Aged , Reproducibility of Results , Students, Medical , Task Performance and Analysis , Young Adult
5.
Adv Appl Microbiol ; 95: 1-67, 2016.
Article in English | MEDLINE | ID: mdl-27261781

ABSTRACT

A major challenge facing agriculture in the 21st century is the need to increase the productivity of cultivated land while reducing the environmentally harmful consequences of mineral fertilization. The microorganisms thriving in association and interacting with plant roots, the plant microbiota, represent a potential resource of plant probiotic function, capable of conjugating crop productivity with sustainable management in agroecosystems. However, a limited knowledge of the organismal interactions occurring at the root-soil interface is currently hampering the development and use of beneficial plant-microbiota interactions in agriculture. Therefore, a comprehensive understanding of the recruitment cues of the plant microbiota and the molecular basis of nutrient turnover in the rhizosphere will be required to move toward efficient and sustainable crop nutrition. In this chapter, we will discuss recent insights into plant-microbiota interactions at the root-soil interface, illustrate the processes driving mineral dynamics in soil, and propose experimental avenues to further integrate the metabolic potential of the plant microbiota into crop management and breeding strategies for sustainable agricultural production.


Subject(s)
Bacteria/metabolism , Microbiota , Minerals/metabolism , Plant Roots/microbiology , Plants/microbiology , Bacteria/classification , Bacteria/isolation & purification , Bacterial Physiological Phenomena , Minerals/analysis , Rhizosphere , Soil Microbiology
6.
Anaesthesia ; 71(5): 565-72, 2016 May.
Article in English | MEDLINE | ID: mdl-26990198

ABSTRACT

UNLABELLED: Our study examined the effectiveness of pulse oximetry sonification enhanced with acoustic tremolo and brightness to help listeners differentiate clinically relevant oxygen saturation ranges. In a series of trials lasting 30 s each, 76 undergraduate participants identified final oxygen saturation range ( TARGET: 100% to 97%; Low: 96% to 90%; Critical: 89% and below), and detected threshold transitions into and out of the target range using conventional sonification (n = 38) or enhanced sonification (n = 38). Median (IQR [range]) accuracy for range identification with the conventional sonification was 80 (70-85 [45-95])%, whereas with the enhanced sonification it was 100 (99-100 [80-100])%; p < 0.001. Accuracy for detecting threshold transitions with the conventional sonification was 60 (50-75 [30-95])%, but with the enhanced sonification it was 100 (95-100 [75-100]%; p < 0.001. Participants can identify clinically meaningful oxygen saturation ranges and detect threshold transitions more accurately with enhanced sonification than with conventional sonification.


Subject(s)
Oximetry/instrumentation , Oximetry/methods , Oxygen/blood , Clinical Alarms , Female , Humans , Male , Reproducibility of Results , Sonication , Sound , Students, Medical , Surveys and Questionnaires , Young Adult
7.
Appl Environ Microbiol ; 82(3): 897-909, 2016 02 01.
Article in English | MEDLINE | ID: mdl-26590287

ABSTRACT

Metagenomics allows the study of genes related to xenobiotic degradation in a culture-independent manner, but many of these studies are limited by the lack of genomic context for metagenomic sequences. This study combined a phenotypic screen known as substrate-induced gene expression (SIGEX) with whole-metagenome shotgun sequencing. SIGEX is a high-throughput promoter-trap method that relies on transcriptional activation of a green fluorescent protein (GFP) reporter gene in response to an inducing compound and subsequent fluorescence-activated cell sorting to isolate individual inducible clones from a metagenomic DNA library. We describe a SIGEX procedure with improved library construction from fragmented metagenomic DNA and improved flow cytometry sorting procedures. We used SIGEX to interrogate an aromatic hydrocarbon (AH)-contaminated soil metagenome. The recovered clones contained sequences with various degrees of similarity to genes (or partial genes) involved in aromatic metabolism, for example, nahG (salicylate oxygenase) family genes and their respective upstream nahR regulators. To obtain a broader context for the recovered fragments, clones were mapped to contigs derived from de novo assembly of shotgun-sequenced metagenomic DNA which, in most cases, contained complete operons involved in aromatic metabolism, providing greater insight into the origin of the metagenomic fragments. A comparable set of contigs was generated using a significantly less computationally intensive procedure in which assembly of shotgun-sequenced metagenomic DNA was directed by the SIGEX-recovered sequences. This methodology may have broad applicability in identifying biologically relevant subsets of metagenomes (including both novel and known sequences) that can be targeted computationally by in silico assembly and prediction tools.


Subject(s)
Bacteria/genetics , Gene Expression , Hydrocarbons, Aromatic/metabolism , Metagenome , Metagenomics/methods , Soil Microbiology , Soil Pollutants/metabolism , Bacteria/growth & development , Bacteria/metabolism , Bacterial Proteins/genetics , Cloning, Molecular , Computer Simulation , Flow Cytometry , Gene Library , Genes, Bacterial , Genes, Reporter , Green Fluorescent Proteins/genetics , Hydrocarbons, Aromatic/analysis , Operon , Phenotype , Sequence Analysis, DNA , Soil Pollutants/analysis , Transcription Factors/genetics
8.
J Hum Nutr Diet ; 25(5): 477-87, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22831286

ABSTRACT

BACKGROUND: Fruit and vegetable-rich diets are associated with a reduced cardiovascular disease (CVD) risk. This protective effect may be a result of the phytochemicals present within fruits and vegetables (F&V). However, there can be considerable variation in the content of phytochemical composition of whole F&V depending on growing location, cultivar, season and agricultural practices, etc. Therefore, the present study investigated the effects of consuming fruits and vegetables as puree-based drinks (FVPD) daily on vasodilation, phytochemical bioavailability, antioxidant status and other CVD risk factors. FVPD was chosen to provide a standardised source of F&V material that could be delivered from the same batch to all subjects during each treatment arm of the study. METHODS: Thirty-nine subjects completed the randomised, controlled, cross-over dietary intervention. Subjects were randomised to consume 200 mL of FVPD (or fruit-flavoured control), daily for 6 weeks with an 8-week washout period between treatments. Dietary intake was measured using two 5-day diet records during each cross-over arm of the study. Blood and urine samples were collected before and after each intervention and vasodilation assessed in 19 subjects using laser Doppler imaging with iontophoresis. RESULTS: FVPD significantly increased dietary vitamin C and carotenoids (P < 0.001), and concomitantly increased plasma α- and ß-carotene (P < 0.001) with a near-significant increase in endothelium-dependent vasodilation (P = 0.060). CONCLUSIONS: Overall, the findings obtained in the present study showed that FVPD were a useful vehicle to increase fruit and vegetable intake, significantly increasing dietary and plasma phytochemical concentrations with a trend towards increased endothelium-dependent vasodilation.


Subject(s)
Antioxidants/metabolism , Cardiovascular Diseases/epidemiology , Fruit , Oxygen/metabolism , Vasodilation/drug effects , Vegetables , Adult , Aged , Antioxidants/pharmacology , Ascorbic Acid/administration & dosage , Beverages , Cardiovascular Diseases/blood , Carotenoids/administration & dosage , Cross-Over Studies , Female , Humans , Male , Middle Aged , Oxidation-Reduction , Oxygen/blood , Seasons , Vasodilation/physiology
9.
Chem Senses ; 37(6): 553-66, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22473924

ABSTRACT

Olfaction begins when an animal draws odorant-laden air into its nasal cavity by sniffing, thus transporting odorant molecules from the external environment to olfactory receptor neurons (ORNs) in the sensory region of the nose. In the dog and other macrosmatic mammals, ORNs are relegated to a recess in the rear of the nasal cavity that is comprised of a labyrinth of scroll-like airways. Evidence from recent studies suggests that nasal airflow patterns enhance olfactory sensitivity by efficiently delivering odorant molecules to the olfactory recess. Here, we simulate odorant transport and deposition during steady inspiration in an anatomically correct reconstructed model of the canine nasal cavity. Our simulations show that highly soluble odorants are deposited in the front of the olfactory recess along the dorsal meatus and nasal septum, whereas moderately soluble and insoluble odorants are more uniformly deposited throughout the entire olfactory recess. These results demonstrate that odorant deposition patterns correspond with the anatomical organization of ORNs in the olfactory recess. Specifically, ORNs that are sensitive to a particular class of odorants are located in regions where that class of odorants is deposited. The correlation of odorant deposition patterns with the anatomical organization of ORNs may partially explain macrosmia in the dog and other keen-scented species.


Subject(s)
Computer Simulation , Nasal Cavity/metabolism , Odorants , Smell/physiology , Air Movements , Animals , Biological Transport , Dogs , Odorants/analysis
10.
J Environ Monit ; 14(3): 782-90, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22237634

ABSTRACT

Flow field flow fractionation (FlFFF) in combination with inductively coupled plasma mass spectrometry (ICP-MS) was used to study the chemical speciation of U and trace metals in depleted uranium (DU) contaminated soils. A chemical extraction procedure using sodium pyrophosphate, followed by isolation of humic and fulvic substances was applied to two dissimilar DU contaminated sample types (a sandy soil and a clay-rich soil), in addition to a control soil. The sodium pyrophosphate fractions of the firing range soils (Eskmeals and Kirkcudbright) were found to contain over 50% of the total U (measured after aqua regia digestion), compared to approximately 10% for the control soil. This implies that the soils from the contaminated sites contained a large proportion of the U within more easily mobile soil fractions. Humic and fulvic acid fractions each gave characteristic peak maxima for analytes of interest (Mn, Fe, Cu, Zn, Pb and U), with the fulvic acid fraction eluting at a smaller diameter (approximately 2.1 nm on average) than the humic fraction (approximately 2.4 nm on average). DU in the fulvic acid fraction gave a bimodal peak, not apparent for other trace elements investigated, including natural U. This implies that DU interacts with the fulvic acid fraction in a different way to all other elements studied.


Subject(s)
Environmental Monitoring/methods , Soil Pollutants/chemistry , Soil/chemistry , Uranium/analysis , Benzopyrans/analysis , Environmental Monitoring/instrumentation , Fractionation, Field Flow , Mass Spectrometry , Soil Pollutants/analysis
11.
Tree Physiol ; 31(2): 150-9, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21388994

ABSTRACT

Current knowledge on tree carbon (C) allocation to wood is particularly scarce in plants subjected to disturbance factors, such as browsing, which affects forest regeneration worldwide and has an impact on the C balance of trees. Furthermore, quantifying the degree to which tree rings are formed from freshly assimilated vs. stored carbohydrates is highly relevant for our understanding of tree C allocation. We used (13)C labelling to quantify seasonal allocation of stored C to wood formation in two species with contrasting wood anatomy: Betula pubescens Ehrh. (diffuse-porous) and Quercus petraea [Matt.] Liebl. (ring-porous). Clipping treatments (66% shoot removal, and unclipped) were applied to analyse the effect of browsing on C allocation into tree rings, plus the effects on tree growth, architecture, ring width and non-structural carbohydrates (NSCs). The relative contribution of stored C to wood formation was greater in the ring-porous (55-70%) than in the diffuse-porous species (35-60%), although each species followed different seasonal trends. Clipping did not cause a significant depletion of C stores in either species. Nonetheless, a significant increase in the proportion of stored C allocated to earlywood growth was observed in clipped birches, and this could be explained through changes in tree architecture after clipping. The size of C pools across tree species seems to be important in determining the variability of seasonal C allocation patterns to wood and their sensibility to disturbances such as browsing. Our results indicate that the observed changes in C allocation to earlywood in birch were not related to variations in the amount or concentration of NSC stores, but to changes in the seasonal availability of recently assimilated C caused by modifications in tree architecture after browsing.


Subject(s)
Betula/anatomy & histology , Betula/growth & development , Quercus/anatomy & histology , Quercus/growth & development , Betula/metabolism , Carbohydrate Metabolism , Feeding Behavior , Plant Stems/anatomy & histology , Plant Stems/chemistry , Plant Stems/growth & development , Plant Stems/metabolism , Quercus/metabolism , Seasons
13.
Environ Sci Technol ; 41(6): 1921-7, 2007 Mar 15.
Article in English | MEDLINE | ID: mdl-17410785

ABSTRACT

For understanding both the environmental behavior and developing remediation treatments for chromium ore processing residue (COPR) it is important to identify all the potentially soluble sources of Cr(VI). Hydrogarnet has been identified as a major phase in COPR and it has been previously speculated that it has a capacity to host Cr(VI). Here we provide direct evidence of this capacity by demonstrating the incorporation of Cr(VI) into laboratory synthesized hydrogarnet. Electron microscopy and energy dispersive X-ray microanalysis show incorporation of approximately 17000-22000 mg Cr(VI) kg(-1) hydrogarnet. X-ray powder diffraction data show that peak intensities are altered by chromium substitution and that chromium substituted hydrogarnets have a smaller unit cell than the pure Ca-Al end member. This is consistent with substitution of hydroxyl tetrahedra by smaller chromate tetrahedra. Electron energy loss spectroscopy confirms the tetrahedral coordination and hexavalent oxidation state of chromium in the hydrogarnets. The maximum amount of hexavalent chromium that can be introduced synthetically corresponds to a replacement of about one out of every eight hydroxyl tetrahedral per unit cell by a CrO4(2-) tetrahedra and tallies closely with the amount of chromium measured in hydrogarnets from COPR. Chromium-bearing hydrogarnet is the most abundant crystalline phase in millions of tons of COPR contaminating land around Glasgow, Scotland, and was recently identified in COPR from sites in North America. Calculations based on its abundance and its Cr(VI) content indicate that hydrogarnet can host as much as 50% of the Cr(VI) found in some COPR samples.


Subject(s)
Chromium/chemistry , Industrial Waste , Mining , Silicates/chemistry , Electron Probe Microanalysis , Microscopy, Electron , Spectrum Analysis/methods
14.
J Microbiol Methods ; 65(3): 476-87, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16216354

ABSTRACT

In this study, we explored whether SYBR Green-based quantitative real-time PCR (qPCR) could be used to determine the copy number of a plasmid and whether the method was broadly applicable to chromosomally encoded genetic elements often occurring in multiple copies, such as rRNA genes and insertion sequences (IS). Three different template sources (whole cells, total DNA, and restriction-enzyme digested total DNA) derived from the bacterium Comamonas sp. strain JS46 were analyzed by qPCR using primer-pairs targeting plasmid pJS46 and three chromosomally encoded sequences (16S rDNA, ISCsp1, and IS1071). The difference between threshold cycle values, C(T), of amplicons targeting these elements and of an amplicon targeting the single-copy reference element mnbA (chromosomally encoded) was used to establish DeltaC(T). DeltaC(T) values were then used to derive copy number. For pJS46, qPCR analyses of whole cells and total DNA underestimated the copy number of pJS46 approximately 7-fold and approximately 2.5-fold, respectively, whereas copy number values derived from qPCR analyses of digested total DNA were comparable to those derived from Southern blot (SB) analyses. In contrast, for the chromosomally encoded elements, qPCR analyses of all three template sources gave copy number values that were virtually identical to or differed by approximately 2 from copy number values derived by SB analysis. These data indicate that qPCR can be used to estimate the copy number of various genetic elements but that the accuracy of qPCR-derived values is affected by the template source.


Subject(s)
DNA Transposable Elements/genetics , Gene Dosage , Genes, rRNA/genetics , Organic Chemicals/metabolism , Plasmids/genetics , Polymerase Chain Reaction/methods , Benzothiazoles , Comamonas/genetics , Comamonas/growth & development , Diamines , Molecular Sequence Data , Quinolines , Reference Standards , Sequence Analysis, DNA
15.
Sci Total Environ ; 360(1-3): 90-7, 2006 May 01.
Article in English | MEDLINE | ID: mdl-16203026

ABSTRACT

Chromite ore processing residue (COPR) waste from a former chromium chemical works (1830-1968) is still contaminating groundwater in Glasgow, Scotland, with carcinogenic hexavalent chromium, Cr(VI). An integrated analytical, experimental and modelling approach has identified and accounted for mineral phases and processes responsible for the retention and release of Cr(VI) under prevailing field conditions. Both the nature of mineral phase retention and the buffered high pH of the sites, however, militate against direct remediative treatment of the source material, for example by the application of generic methods (e.g. FeSO4) that have been successfully employed elsewhere for the reduction of Cr(VI) to Cr(III) in other matrices. The interception and treatment of groundwater to remove Cr(VI) and the capping of sites to reduce human exposure to airborne Cr(VI)-contaminated dust may well be more realistic and effective, at least in the short to medium term.


Subject(s)
Chromium/analysis , Hazardous Waste , Industrial Waste , Waste Management/methods , Dust/prevention & control , Humans , Industrial Waste/analysis , Inhalation Exposure/prevention & control , Metallurgy , Minerals/analysis , Minerals/chemistry , Models, Theoretical , Soil Pollutants/analysis , Solubility , Water Pollutants, Chemical/analysis
16.
Chemosphere ; 63(11): 1942-52, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16310826

ABSTRACT

Urban soils and especially their microbiology have been a neglected area of study. In this paper, we report on microbial properties of urban soils compared to rural soils of similar lithogenic origin in the vicinity of Aberdeen city. Significant differences in basal respiration rates, microbial biomass and ecophysiological parameters were found in urban soils compared to rural soils. Analysis of community level physiological profiles (CLPP) of micro-organisms showed they consumed C sources faster in urban soils to maintain the same level activity as those in rural soils. Cu, Pb, Zn and Ni were the principal elements that had accumulated in urban soils compared with their rural counterparts with Pb being the most significant metal to distinguish urban soils from rural soils. Sequential extraction showed the final residue after extraction was normally the highest proportion except for Pb, for which the hydroxylamine-hydrochloride extractable Pb was the largest part. Acetic acid extractable fraction of Cd, Cu, Ni, Pb and Zn were higher in urban soils and aqua regia extractable fraction were lower suggesting an elevated availability of heavy metals in urban soils. Correlation analyses between different microbial indicators (basal respiration, biomass-C, and sole C source tests) and heavy metal fractions indicated that basal respiration was negatively correlated with soil Cd, Cu, Ni and Zn inputs while soil microbial biomass was only significantly correlated with Pb. However, both exchangeable and iron- and manganese-bound Ni fractions were mostly responsible for shift of the soil microbial community level physiological profiles (sole C source tests). These data suggest soil microbial indicators can be useful indicators of pollutant heavy metal stress on the health of urban soils.


Subject(s)
Environmental Monitoring/methods , Metals, Heavy/analysis , Soil Microbiology , Soil Pollutants/analysis , Biological Availability , Carbon/metabolism , Chemistry, Physical/methods , Cities , Hydroxylamine/chemistry , Lead/analysis , Lead/isolation & purification , Metals, Heavy/pharmacokinetics , Metals, Heavy/toxicity , Rural Population , Soil
17.
New Phytol ; 161(3): 811-818, 2004 Mar.
Article in English | MEDLINE | ID: mdl-33873711

ABSTRACT

• This study examined morphological and topological responses of nodal root axes to defoliation in a fast- and a slow-growing grass species. • Vegetative tillers of both Lolium perenne and Festuca ovina were grown on slant boards and either left intact or subjected to repeated defoliation, under both a high nitrogen (N) and a low N supply. Root length, diameter and branching characteristics were measured on individual nodal root axes. • The total axis root length of F. ovina was less when plants had been defoliated. Root axis weight, primary root axis length and primary root diameter were also less with defoliation than an undefoliated control, under high N. Under low N conditions the root axes of F. ovina had a more randomly branched topology without defoliation. For L. perenne under low N conditions, the length of the primary root axis was longer with defoliation than in an undefoliated control, while the primary root axis diameter decreased. By contrast to F. ovina, the root axes of L. perenne had a more randomly branched topology without defoliation only when supplied with high N. • The greatest plasticity in branching caused by defoliation was observed under high N for L. perenne and under low N for F. ovina. Although grass root axis topology has, in general, a herringbone in structure, the nodal root system can alter root axis structure in response to defoliation.

18.
Sci Total Environ ; 308(1-3): 195-210, 2003 Jun 01.
Article in English | MEDLINE | ID: mdl-12738213

ABSTRACT

A range of techniques, normally associated with mineralogical studies of soils and sediments, has been used to characterise the solid materials found on sites contaminated with chromite ore processing residue (COPR). The results show that a wide range of minerals are present, many of which are found extensively in high-temperature synthetic systems such as cements and clinkers and their low temperature hydration products. Thus, the minerals in COPR can be divided into three main categories: unreacted feedstock ore (chromite); high temperature phases produced during chromium extraction (brownmillerite, periclase and larnite); and finally, minerals formed under ambient weathering conditions on the disposal sites (brucite, calcite, aragonite, ettringite, hydrocalumite, hydrogarnet). Apart from chromite, chromium occurs in brownmillerite, ettringite, hydrocalumite and hydrogarnet. Detailed study of the chemistry and stoichiometry of chromium-bearing phases in conjunction with phase abundance provides a quantitative description of the solid state speciation of Cr(III) and Cr(VI) in and amongst these minerals and in the COPR as a whole. Of the total chromium present in the samples most, approximately 60-70% is present as Cr(III) in chromite, whilst brownmillerite also represents a significant reservoir of Cr(III) which is approximately 15% of the total. The remaining chromium, between 20 and 25%, is present as Cr(VI) and resides mainly in hydrogarnet, and to a slightly lesser extent in hydrocalumite. In the latter, it is present principally in an exchangeable anionic form. Chromium (VI) is also present in ettringite, but quantitatively ettringite is a much less important reservoir of Cr(VI), accounting for approximately 3% of total chromium in one sample, but less than 1% in the other two. This description provides insight into the processes likely to control the retention and release of Cr(VI) from COPR-contaminated sites. Such information is of particular value in chemical modelling of the system, in risk assessment and in the development of methods of informed remediation.

19.
Mutat Res ; 508(1-2): 59-70, 2002 Oct 31.
Article in English | MEDLINE | ID: mdl-12379462

ABSTRACT

The biological activity of many nitrosubstituted compounds, many of which are produced commercially or have been identified as environmental contaminants, is dependent on metabolic activation catalyzed by nitroreductases. In the current study, we have cloned a nitroreductase gene, Salmonella typhimurium nitroreductase A (snrA), from S. enterica serovar Typhimurium strain TA1535, and characterized the purified gene product. SnrA is 240 amino acids in length and shares 87% sequence identity to the Escherichia coli homolog, E. coli nitroreductase A (NfsA). SnrA is the major nitroreductase in S. enterica serovar Typhimurium strain TA1535 and catalyzes nitroreduction through a ping-pong bi-bi mechanism in a NADPH and flavine mononucleotide (FMN) dependent manner. SnrA exhibits extremely low levels of FMN reductase activity but the nitroreductase activity of SnrA is competitively inhibited by exogenously added FMN. Treatment of TA1535 with paraquat resulted in induction of nitroreductase activity, suggesting that SnrA is a member of the S. enterica serovar Typhimurium SoxRS regulon associated with cellular defense against oxidative damage. Examination of the microbial genomes databases shows that SnrA homologs are widely distributed in the microbial world, being present in isolates of both Archea and Eubacteria. Southern hybridization and PCR failed to detect the snrA gene in the closely related S. enterica serovar Typhimurium strain TA1538. S. enterica serovar Typhimurium strains TA1535 and TA1538 and their derivatives are commonly used in mutagenicity testing. Differences in metabolic capacity between these two strains may have implications for the interpretation of mutagenicity data.


Subject(s)
Nitroreductases/genetics , Nitroreductases/metabolism , Salmonella typhi/enzymology , Amino Acid Sequence , Cloning, Molecular , FMN Reductase/metabolism , Flavin Mononucleotide/metabolism , Molecular Sequence Data , Mutagenicity Tests/methods , NADP/metabolism , Nitroreductases/drug effects , Paraquat/pharmacology , Salmonella typhi/drug effects , Salmonella typhi/genetics , Sequence Homology, Amino Acid
20.
Pest Manag Sci ; 58(9): 964-6, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12233189

ABSTRACT

In accordance with the EPPO guideline for the efficacy evaluation of plant protection products, resistance risk analysis PP 1/213(1), a method was established to determine the baseline sensitivity of key weed species to florasulam, a new triazolopyrimidine sulfonanilide herbicide for post-emergence control of dicotyledonous weeds in cereals. The aim of the baseline monitoring project was to understand the natural variation in response to florasulam of diverse populations of Papaver rhoeas at the time of product launch. The method entailed seed collection from representative agricultural areas throughout Europe. The seed was subjected to glasshouse tests where dose-response studies were conducted and ED80 values generated. This enabled a sensitivity index to be calculated for each country, giving an indication of the variation in P rhoeas response to florasulam in the populations tested.


Subject(s)
Herbicides/toxicity , Papaver/drug effects , Pyrimidines/toxicity , Sulfonamides/toxicity , Dose-Response Relationship, Drug , Europe , Genetic Variation , Seeds/drug effects
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