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1.
Australas J Ageing ; 42(4): 710-719, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37518833

ABSTRACT

OBJECTIVE: To describe the economic and cost considerations of mobile X-ray services (MXS) in residential aged care facilities (RACFs), according to stakeholders (involved in residents' healthcare), residents living in RACFs and informal carers (ICs) of residents. METHODS: Semistructured interviews were conducted with 20 residents and 27 ICs recruited from six RACFs across metropolitan Adelaide (South Australia, Australia), and 22 stakeholders, on their perspectives of using MXS in RACFs. Data relating to economic and cost considerations were extracted and analysed using thematic analysis. RESULTS: Residents' mean age was 85 years, 60% were women and 40% had experienced an MXS in the last 12 months. Most ICs were daughters (70%) and wives (11%) and 30% had a family member who had experienced an MXS in the last 12 months. Stakeholders included RACF staff, GPs, a hospital avoidance program clinician, paramedics, emergency department clinicians, MXS radiographers and manager, and a radiologist. Four themes were presented: (1) business considerations, where private providers found it necessary to charge residents a co-payment to deliver MXS; (2) cost and payment process as a potential barrier to using MXS, with varied willingness and ability to pay for an MXS co-payment, and equity concerns; (3) overcoming cost and payment barriers, with staff and consumers sometimes using strategies to overcome cost barriers; and (4) perceived cost benefits of MXS to the healthcare system, residents and ICs. CONCLUSIONS: Mobile X-ray services providers charge residents an upfront co-payment for business viability, which can be a barrier to some residents wishing to access MXS.


Subject(s)
Delivery of Health Care , Homes for the Aged , Aged , Humans , Female , Aged, 80 and over , Male , X-Rays , Australia , Emergency Service, Hospital
2.
BMC Geriatr ; 23(1): 458, 2023 07 25.
Article in English | MEDLINE | ID: mdl-37491218

ABSTRACT

BACKGROUND: Informal carers (ICs) of residents living in nursing homes (NH) have a key role in the care of residents, including making decisions about and providing care. As radiology has a role in decision making about care, it is important to understand IC's perspectives about resident's use of mobile X-ray services (MXS). The aim was to explore the perspectives of ICs of residents living in nursing homes about the use of MXS. METHODS: From November 2020 to February 2021, twenty ICs of residents living in four nursing homes in different areas of one Australian city participated. Their perspectives of MXS, including benefits and barriers, were explored in semi-structured interviews. Data were analysed using thematic analysis. RESULTS: ICs were resident's children (80%) and spouses (20%). One resident had received a MXS. Four themes were developed: (1) a priority for resident well-being, where ICs were positive about using MXS, because residents could receive healthcare without transfer; (2) MXS could reduce carer burden; (3) economic considerations, where MXS could reduce health system burden but the MXS call-out fee could result in health inequities; and (4) pathways to translation, including the need to improve consumer awareness of MXS, ensure effective processes to using MXS,, consider nursing home staff levels to manage MXS and ICs expectations about quality and availability of MXS. CONCLUSIONS: ICs consider MXS can benefit resident well-being by potentially reducing transfers to hospital or radiology facilities and advocated equitable access. ICs cautioned that the quality and safety of healthcare delivered in nursing homes should equal what they would receive in hospitals.


Subject(s)
Caregivers , Radiology , Humans , X-Rays , Australia , Nursing Homes , Delivery of Health Care , Qualitative Research
3.
BMC Geriatr ; 23(1): 50, 2023 01 27.
Article in English | MEDLINE | ID: mdl-36707769

ABSTRACT

BACKGROUND: Older people have increasingly complex healthcare needs, often requiring appropriate access to diagnostic imaging, an essential component of their health and disease management planning. Ultrasound is a safe imaging tool used to diagnose several conditions commonly experienced by older people such as deep vein thrombosis. PURPOSE: To evaluate the utilisation of major ultrasound services by Australians ≥ 65 years old between 2009- and 2019. METHODS: This population-based and yearly cross-sectional study of ultrasound utilisation per 1,000 Australians ≥ 65 years old was conducted using publicly available data sources. Overall, examination site and age- and sex-specific incidence rate (IR) of ultrasound per 1,000 people, adjusted incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated using negative binomial regression models. RESULTS: Over the study period, the crude utilisation of ultrasound increased by 83% in older Australians. Most ultrasound examinations were conducted on extremities (39%) and the chest (21%), with 25% of all ultrasounds investigating the vascular system. More men than women use ultrasounds of the chest (184/1,000 vs 268/1,000 people), particularly echocardiograms (177/1,000 vs 261/1,000 people), and abdomen (88/1,000 vs 92/1,000 people), especially in those ≥ 85 years old. Hip and pelvic ultrasound were used more by women than men (212/1,000 vs 182/1,000 people). There were increases in vascular abdominal (IRR:1.07, 95%CI:1.06-1.08) and extremeties (IRR:1.06, 95%CI:1.05-1.07) ultrasounds over the study period, particularly in ≥ 75 years old men. CONCLUSIONS: Ultrasound is a common and increasingly used diagnostic tool for conditions commonly experienced by older Australians.


Subject(s)
Delivery of Health Care , Health Facilities , Male , Humans , Female , Aged , Aged, 80 and over , Cross-Sectional Studies , Australia/epidemiology , Ultrasonography
4.
BMC Geriatr ; 22(1): 700, 2022 08 23.
Article in English | MEDLINE | ID: mdl-35999503

ABSTRACT

BACKGROUND: There is interest in reducing avoidable emergency department presentations from residential aged care facilities (RACF). Mobile x-ray services may enable the delivery of healthcare in residential aged care facilities. Accordingly, the Australian Government in November 2019 introduced a Medicare Benefit Schedule rebate providing for a 'call-out' fee payable to radiology service providers. This study aims to understand stakeholder perspectives on the benefits of mobile x-ray services and the factors influencing their adoption by RACFs. DESIGN, SETTING, PARTICIPANTS: Twenty-two semi-structured interviews were conducted between October 2020 and February 2021 with a range of stakeholders involved in healthcare delivery to residents: a) general practitioners; b) emergency department clinicians; c) paramedic clinicians; d) a hospital avoidance clinician; e) radiology clinicians and managers; and f) aged care clinicians and managers. Thematic analysis was conducted. RESULTS: Mobile x-ray services were considered valuable for RACF residents. Lack of timely general practitioner in-person assessment and referral, as well as staffing deficits in residential aged care facilities, reduces optimal use of mobile x-ray services and results in potentially unnecessary hospital transfers. CONCLUSIONS: The use of mobile x-ray services, as a hospital avoidance strategy, depends on the capacity of RACFs to provide more complex healthcare-in-place. However, this requires greater access to general practitioners for in-person assessment and referral, adequate staffing numbers and appropriately skilled nursing staff within residential aged care facilities.


Subject(s)
Homes for the Aged , Radiology , Aged , Australia , Delivery of Health Care , Humans , National Health Programs , Nursing Homes , X-Rays
5.
J Am Med Dir Assoc ; 23(9): 1564-1572.e9, 2022 09.
Article in English | MEDLINE | ID: mdl-35667412

ABSTRACT

OBJECTIVES: To (1) estimate incidence, trends, and determinants of government-subsidized diagnostic radiography (ie, plain x-ray) services utilization by Australian long-term care facility (LTCF) residents between 2009 and 2016; (2) examine national variation in services used. DESIGN: A repeated cross-sectional study. SETTING AND PARTICIPANTS: Australian LTCF residents who were ≥65 years old. METHODS: Medicare Benefits Schedule subsidized plain x-rays employed for diagnosing fall-related injuries, pneumonia, heart failure, and acute abdomen or bowel obstruction were identified. Yearly sex- and age-standardized utilization rates were calculated. Poisson and negative binomial regression models were employed. Facility-level variation was examined graphically. Overall and examination site-specific analyses were conducted. RESULTS: A total of 521,497 LTCF episodes for 453,996 individuals living in 3018 LTCFs were examined. The median age was 84 years (interquartile range 79-88), 65% (n = 339,116) were women, and 53.9% (n = 281,297) had dementia. In addition, 34.5% (n = 179,811) of episodes had at least one x-ray service. Overall, there was a 12% increase in utilization between 2009 and 2016 (from 535/1000 in 2009 to 602/1000 person-years in 2016, incidence rate ratio=1.02, 95% confidence interval 1.02-1.02). Factors associated with x-ray use included being 80-89 years old, being a man, not having dementia, having multiple health conditions (4-6 or ≥7 compared to 0-3), being at a smaller facility (0-24 bed compared to 50-74), facility located in the Australian state of New South Wales, or in major cities (compared to regional areas). National variation in x-ray service use, with largest differences observed by state, was detected. CONCLUSIONS AND IMPLICATIONS: Plain x-ray service utilization by LTCF residents increased 12% between 2009 and 2016. Sex, age, dementia status, having multiple health conditions as well as facility size, and location were associated with plain x-ray use in LTCFs and use varied geographically. Differences in x-ray service utilization by residents highlight lack of consistent access and potential over- or underutilization.


Subject(s)
Dementia , Long-Term Care , Aged , Aged, 80 and over , Australia , Cross-Sectional Studies , Dementia/diagnostic imaging , Dementia/epidemiology , Female , Humans , Male , Multimorbidity , National Health Programs , X-Rays
6.
BMC Geriatr ; 22(1): 525, 2022 06 25.
Article in English | MEDLINE | ID: mdl-35752763

ABSTRACT

BACKGROUND: Mobile X-ray services (MXS) could be used to investigate clinical issues in aged care residents within familiar surroundings, reducing transfers to and from emergency departments and enabling healthcare to be delivered in residential aged care facilities. There is however little research exploring consumer perspectives about such services. The objective of this research was to explore the perspectives and preferences of residents about the provision of MXS in residential aged care facilities, including their knowledge about the service, perceived benefits, and factors that require consideration for effective implementation. METHODS: A qualitative study design was used. The setting for the study included four residential aged care facilities of different sizes from different parts of a South Australian city. Purposive sampling was used to recruit participants. 16 residents participated in semi-structured interviews that were audio-recorded and transcribed verbatim. Data were inductively derived using thematic analysis. RESULTS: Participants had a mean age of 85 years, 56% were female, 25% had dementia and 25% had had a mobile X-ray in the last 12 months. Four themes were developed. Participants preferred mobile X-rays, provided as healthcare-in-place, to improve accessibility to them and minimize physical and psychological discomfort. Participants had expectations about the processes for receiving mobile X-rays. Costs of X-rays to people, family and society were a consideration. Decision making required residents be informed about mobile X-rays. CONCLUSIONS: Residents have positive views of MXS as they can receive healthcare-in-place, with familiar people and surroundings. They emphasised that MXS delivered in residential aged care facilities need to be of equivalent quality to those found in other settings. Increased awareness of mobile X-ray services is required.


Subject(s)
Homes for the Aged , Nursing Homes , Aged , Aged, 80 and over , Australia , Delivery of Health Care , Female , Humans , Male , Qualitative Research , Residential Facilities , X-Rays
7.
Harmful Algae ; 113: 102185, 2022 03.
Article in English | MEDLINE | ID: mdl-35287926

ABSTRACT

Although there is growing evidence that benthic cyanobacteria represent a significant source of toxins and taste and odour (T&O) compounds in water bodies globally, water utilities rarely monitor for them. Benthic cyanobacteria grow in an array of matrices such as sediments, biofilms, and floating mats, and they can detach and colonize treatment plants. The occurrence of compounds produced by benthic species across matrix and climate types has not been systematically investigated. Consequently, there is a lack of guidance available to utilities to monitor for and mitigate the risk associated with benthic cyanobacteria. To assess toxin and T&O risk across climatic zones and provide guidance to water utilities for the monitoring of benthic mats, two field surveys were conducted across three continents. The surveys examined the occurrence of six secondary metabolites and associated genes, namely, geosmin, 2-methylisoborneol (MIB), anatoxin-a, saxitoxin, microcystin, and cylindrospermopsin, in benthic environmental samples collected across three climates (i.e., temperate, sub-tropical, and tropical) and a range of matrix types. Existing enzyme-linked immunosorbent assays (ELISAs) and qPCR assays and were used to measure compound concentrations and their associated genes in samples. A novel qPCR assay was designed to differentiate the production of MIB by actinobacteria from that of cyanobacteria. MIB occurrence was higher in warmer climates than temperate climates. Cyanobacteria in benthic mats were the major producers of taste and odour compounds. Floating mats contained significantly higher concentrations of geosmin and saxitoxins compared to other matrix types. Samples collected in warmer areas contained significantly more saxitoxin and cylindrospermopsin than samples collected in temperate climates. While these trends were mainly indicative, they can be used to establish monitoring practices. These surveys demonstrate that benthic mats are significant contributors of secondary metabolites in source water and should be monitored accordingly. Benthic cyanobacteria were the sole producers of T&O in up to 17% of the collected samples compared to actinobacteria, which were sole producers in only 1% of the samples. The surveys also provided a platform of choice for the transfer of methodologies and specific knowledge to participating utilities to assist with the establishment of monitoring practices for benthic cyanobacteria and associated secondary metabolites.


Subject(s)
Cyanobacteria , Cyanobacteria/genetics , Odorants , Saxitoxin/metabolism
8.
BMC Geriatr ; 22(1): 100, 2022 02 04.
Article in English | MEDLINE | ID: mdl-35120445

ABSTRACT

BACKGROUND: Older Australians are major health service users and early diagnosis is key in the management of their health. Radiological services are an important component of diagnosis and disease management planning in older Australians, but their national utilisation of diagnostic services has never been investigated in Australia. PURPOSE: This study aims to evaluate the utilisation of major plain X-rays by Australians ≥ 65 years old. METHODS: A population-based epidemiological evaluation and yearly cross-sectional analyses of X-ray examinations per 1,000 Australians aged ≥ 65 years old between 2009 and 2019 were conducted using publicly available Medicare Benefits Schedule and Australian Bureau of Statistics data sources. Age and sex specific incidence rate (IR) of plain X-rays per 1,000 Australians, adjusted incidence rate ratios (IRR) and 95% confidence intervals (CI) were estimated using a negative binomial regression model. RESULTS: During the study period, the Australian population over 65 years old increased by 39% while the crude plain X-ray utilisation by this population increased by 63%. Most X-rays were conducted on extremities or the chest. Men used chest radiography more than women, and particularly for lungs, where the incidence increased the most in those ≥ 85 years old. There was an increase in X-rays of extremities and the hip joint between 2009-10 and 2013-14 in people ≥ 85 years old. CONCLUSION: The utilisation of plain X-rays of the chest, the gastro-intestinal tract and extremities was high and has increased among older Australians between 2009-10 and 2018-19. Plain X-rays remain a commonly used diagnostic tool for conditions affecting the older population.


Subject(s)
National Health Programs , Aged , Aged, 80 and over , Australia/epidemiology , Cross-Sectional Studies , Female , Humans , Male , Radiography , X-Rays
10.
Water Res ; 169: 115222, 2020 Feb 01.
Article in English | MEDLINE | ID: mdl-31675609

ABSTRACT

Benthic cyanobacteria are a nuisance because they produce highly potent toxins and taste and odour compounds. Despite this, benthic cyanobacteria remain far less studied than their planktonic counterparts. For example, little is known about their growth or the seasonality of their secondary metabolite production. Moreover, sampling and monitoring techniques commonly used for the survey of planktonic species are not necessarily applicable to benthic forms. This study aimed to develop and validate a new sampling device for the routine monitoring of benthic mats. Molecular monitoring techniques were established and validated on environmental samples collected in a South Australian reservoir (SA-L2). A total of eight qPCR assays were applied to samples in order to track seasonal variations in cyanobacteria concentrations and associated secondary metabolite production. Next Generation Sequencing was utilised to conduct a microbial community composition analysis and to select the most appropriate substrate material for the sampling of benthic cyanobacteria. The concentration of the secondary metabolites geosmin and 2-methyl-isoborneol were quantified using High-Performance Liquid Chromatography, and concentrations of key nutrients (N, P) were quantified in water samples. The sampling device designed proved efficient and easy to use in the field. The qPCR assay designed for the amplification of the cyanobacterial MIB synthase had a high efficiency with a minimum limit of quantification of 4 cell-equivalents per reaction and identified a potential source of MIB in SA-L2 Reservoir. The peak season for benthic growth and secondary metabolite production was observed in spring. Proportionally, 35% of the variability in water geosmin concentrations can be explained by benthic actinobacterial and cyanobacterial activity, showing that freshwater benthic mats represent a significant source of taste and odour compounds.


Subject(s)
Cyanobacteria , Australia , Fresh Water , Odorants , Taste
11.
Nat Rev Genet ; 20(10): 615-628, 2019 10.
Article in English | MEDLINE | ID: mdl-31300751

ABSTRACT

Billions of hectares of natural ecosystems have been degraded through human actions. The global community has agreed on targets to halt and reverse these declines, and the restoration sector faces the important but arduous task of implementing programmes to meet these objectives. Existing and emerging genomics tools offer the potential to improve the odds of achieving these targets. These tools include population genomics that can improve seed sourcing, meta-omics that can improve assessment and monitoring of restoration outcomes, and genome editing that can generate novel genotypes for restoring challenging environments. We identify barriers to adopting these tools in a restoration context and emphasize that regulatory and ethical frameworks are required to guide their use.


Subject(s)
Conservation of Natural Resources/methods , Genomics/methods , Animals , Biodiversity , Ecosystem , Humans
12.
Water Res ; 124: 454-464, 2017 11 01.
Article in English | MEDLINE | ID: mdl-28787682

ABSTRACT

Cyanobacteria represent a health hazard worldwide due to their production of a range of highly potent toxins in diverse aquatic environments. While planktonic species have been the subject of many investigations in terms of risk assessment, little is known about benthic forms and their impact on water quality or human and animal health. This study aimed to purify isolates from environmental benthic biofilms sampled from three different drinking water reservoirs and to assess their toxin production by using the following methods: Enzyme-Linked Immunosorbent Assay (ELISA), High-Performance Liquid Chromatography (HPLC), Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) and quantitative PCR (qPCR). Microscopic observation of the isolates allowed the identification of various filamentous cyanobacterial genera: Anabaena (benthic form), Calothrix and Nostoc from the Nostocales and Geitlerinema, Leptolyngbya, Limnothrix, Lyngbya, Oxynema, Phormidium and Pseudanabaena representing non-heterocystous filamentous cyanobacteria. The Phormidium ambiguum strain AWQC-PHO021 was found to produce 739 ng/mg of dry weight (d/w) of cylindrospermopsin and 107 ng/mg (d/w) of deoxy-cylindrospermopsin. The Nostoc linckia strain AWQC-NOS001 produced 400 ng/mg (d/w) of a microcystin analogue. This is the first report of hepatotoxin production by benthic cyanobacteria in temperate Australian drinking water reservoirs. These findings indicate that water quality monitoring programs need to consider benthic cyanobacteria as a potential source of toxins.


Subject(s)
Bacterial Toxins/analysis , Cyanobacteria/chemistry , Drinking Water , Microcystins/analysis , Uracil/analogs & derivatives , Alkaloids , Animals , Australia , Cyanobacteria Toxins , Humans , Tandem Mass Spectrometry , Uracil/analysis
13.
Water Res ; 118: 227-238, 2017 07 01.
Article in English | MEDLINE | ID: mdl-28433693

ABSTRACT

The presence of toxigenic cyanobacteria (blue-green algae) in drinking water reservoirs poses a risk to human and animal health worldwide. Guidelines and health alert levels have been issued in the Australian Drinking Water Guidelines for three major toxins, which are therefore the subject of routine monitoring: microcystin, cylindrospermopsin and saxitoxin. While it is agreed that these toxic compounds should be monitored closely, the routine surveillance of these bioactive chemicals can be done in various ways and deciding which technique to use can therefore be challenging. This study compared several assays available for the detection of these toxins and their producers in environmental samples: microscopy (for identification and enumeration of cyanobacteria), ELISA (Enzyme-Linked ImmunoSorbant Assay), PPIA (Protein phosphatase inhibition assay), PSI (Protein synthesis inhibition), chemical analysis and PCR (Polymerase Chain Reaction). Results showed that there was generally a good correlation between the presence of potentially toxigenic cyanobacteria and the detection of the toxin by ELISA. Nevertheless data suggest that cell numbers and toxin concentrations measured in bioassays do not necessarily correlate and that enumeration of potentially toxic cyanobacteria by microscopy, while commonly used for monitoring and risk assessment, is not the best indicator of real toxin exposure. The concentrations of saxitoxins quantified by ELISA were significantly different than those measured by LC-MS, while results were comparable in both assays for microcystin and cylindrospermopsin. The evaluation of these analytical methods led to the conclusion that there is no "gold standard" technique for the detection of the aforementioned cyanotoxins but that the choice of detection assay depends on cost, practicality, reliability and comparability of results and essentially on the question to be answered, notably on toxin exposure potential.


Subject(s)
Cyanobacteria , Drinking Water , Microcystins , Risk Assessment , Animals , Australia , Bacterial Toxins , Humans , Reproducibility of Results , Saxitoxin
14.
Sci Total Environ ; 565: 1192-1200, 2016 Sep 15.
Article in English | MEDLINE | ID: mdl-27265732

ABSTRACT

In conventional water treatment processes, where the coagulation and flocculation steps are designed to remove particles from drinking water, cyanobacteria are also concentrated into the resultant sludge. As a consequence, cyanobacteria-laden sludge can act as a reservoir for metabolites such as taste and odour compounds and cyanotoxins. This can pose a significant risk to water quality where supernatant from the sludge treatment facility is returned to the inlet to the plant. In this study the complex processes that can take place in a sludge treatment lagoon were investigated. It was shown that cyanobacteria can proliferate in the conditions manifest in a sludge treatment lagoon, and that cyanobacteria can survive and produce metabolites for at least 10days in sludge. The major processes of metabolite release and degradation are very dependent on the physical, chemical and biological environment in the sludge treatment facility and it was not possible to accurately model the net effect. For the first time evidence is provided to suggest that there is a greater risk associated with recycling sludge supernatant than can be estimated from the raw water quality, as metabolite concentrations increased by up to 500% over several days after coagulation, attributed to increased metabolite production and/or cell proliferation in the sludge.


Subject(s)
Cyanobacteria/physiology , Drinking Water/chemistry , Drinking Water/microbiology , Water Pollutants, Chemical/analysis , Water Purification , Flocculation , Recycling , South Australia , Water Supply
16.
Syst Appl Microbiol ; 38(3): 141-58, 2015 May.
Article in English | MEDLINE | ID: mdl-25757799

ABSTRACT

Twenty strains of Planktothrix and five of 'Oscillatoria' were characterized by a polyphasic approach, for clarification of their taxonomic relationships. Emphasis was given to the strains (17) of the Pasteur Culture Collection of Cyanobacteria (PCC). Phenotypic characters analyzed comprised morphology, phycobiliprotein composition, temperature and salinity tolerance. The gvpA gas vesicle gene was detected by PCR in all strains, and transmission electron microscopy confirmed gas vesicle formation in the strains of 'Oscillatoria'. MALDI-TOF mass spectrometry revealed 13 chemotypes, nine of which produce microcystins. A multi-locus sequence typing (MLST) analysis was conducted using individual and concatenated nucleotide sequences of the 16S rDNA, internal transcribed spacer (ITS), gyrB, rpoC1 and rpoB. The results highlighted an unexpected diversity within the genus Planktothrix, showing that the five strains of 'Oscillatoria' need to be included in this taxon. Consequently, the genus consists of seven phylogenetic clusters, three of which represent new species, named Planktothrix paucivesiculata sp. nov.ICNP (type strain: PCC 8926T), Planktothrix tepida sp. nov.ICNP (type strain: PCC 9214T) and Planktothrix serta sp. nov.ICNP (type strain: PCC 8927T). These, together with the emended genus Planktothrix and its type species P. agardhii, valid taxa under the ICN, are described/re-described for gaining nomenclatural standing under the ICNP.


Subject(s)
Cyanobacteria/classification , Cyanobacteria/genetics , Cluster Analysis , Cyanobacteria/cytology , Cyanobacteria/physiology , Cytoplasmic Vesicles/ultrastructure , DNA Gyrase/genetics , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , DNA, Ribosomal Spacer/chemistry , DNA, Ribosomal Spacer/genetics , DNA-Directed RNA Polymerases/genetics , Microscopy, Electron, Transmission , Molecular Sequence Data , Multilocus Sequence Typing , Phycobiliproteins/analysis , Phylogeny , RNA, Ribosomal, 16S/genetics , Salinity , Sequence Analysis, DNA , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Temperature , Terminology as Topic
17.
Water Res ; 47(10): 3444-54, 2013 Jun 15.
Article in English | MEDLINE | ID: mdl-23622984

ABSTRACT

Geosmin has often been associated with off-flavor problems in drinking water with Anabaena sp. as the major producer. Rapid on-site detection of geosmin-producers as well as geosmin is important for a timely management response to potential off-flavor events. In this study, quantitative polymerase chain reaction (qPCR) methods were developed to detect the levels of Anabaena sp. and geosmin, respectively, by designing two PCR primer sets to quantify the rpoC1 gene (ARG) and geosmin synthase one (GSG) in Anabaena sp. in freshwater systems. The ARG density determined by qPCR assay is highly related to microscopic cell count (r(2) = 0.726, p < 0.001), and the limit of detection (LOD) and limit of quantification (LOQ) of the qPCR method were 0.02 pg and 0.2 pg of DNA, respectively. At the same time, the relationship between geosmin concentrations measured by gas chromatography-mass spectrometry (GC-MS) and GSG copies was also established (r(2) = 0.742, p < 0.001) with similar LOD and LOQ values. Using the two qPCR protocols, we succeeded in measuring different levels of ARG and GSG copies in different freshwater systems with high incidence environmental substrata and diverse ecological conditions, showing that the methods developed could be applied for environmental monitoring. Moreover, comparing to the microscopic count and GC-MS analytical methods, the qPCR methods can reduce the time-to-results from several days to a few hours and require considerably less traditional algal identification and taxonomic expertise.


Subject(s)
Anabaena/genetics , Anabaena/metabolism , Fresh Water/microbiology , Naphthols/metabolism , Polymerase Chain Reaction/methods , DNA Primers , Environmental Monitoring/methods , Gas Chromatography-Mass Spectrometry/methods , Limit of Detection , Naphthols/analysis , Polymerase Chain Reaction/standards , Reproducibility of Results , Time Factors , Water Microbiology
18.
Int J Syst Evol Microbiol ; 61(Pt 1): 170-183, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20190018

ABSTRACT

The use of morphological characters for the classification of cyanobacteria has often led to ambiguous strain assignment. In the past two decades, the availability of sequences, such as those of the 16S rRNA, nif, cpc and rpoC1 genes, and the use of metagenomics, has steadily increased and has made the reconstruction of evolutionary relationships of some cyanobacterial groups possible in addition to improving strain assignment. Conserved indels (insertions/deletions) are present in all cyanobacterial RpoB (ß subunit of RNA polymerase) sequences presently available in public databases. These indels are located in the Rpb2_6 domain of RpoB, which is involved in DNA binding and DNA-directed RNA polymerase activity. They are variable in length (6-44 aa) and sequence, and form part of what appears to be a longer signature sequence (43-81 aa). Indeed, a number of these sequences turn out to be distinctive among several strains of a given genus and even among strains of a given species. These signature sequences can thus be used to identify cyanobacteria at a subgenus level and can be useful molecular markers to establish the taxonomic positions of cyanobacterial isolates in laboratory cultures, and/or to assess cyanobacterial biodiversity in space and time in natural ecosystems.


Subject(s)
Bacterial Proteins/genetics , Bacterial Typing Techniques/methods , Cyanobacteria/classification , Cyanobacteria/genetics , DNA-Directed RNA Polymerases/genetics , Molecular Typing/methods , DNA, Bacterial/genetics , INDEL Mutation
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