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14
result(s) for
"Betancourt, Doris A."
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Microbial volatile organic compound emissions from Stachybotrys chartarum growing on gypsum wallboard and ceiling tile
by
Krebs, Ken
,
Moore, Scott A
,
Martin, Shayna M
in
Anisole
,
Calcium Sulfate
,
Environmental Microbiology
2013
Stachybotrys chartarum is a filamentous mold frequently identified among the mycobiota of water-damaged building materials. Growth of S. chartarum on suitable substrates and under favorable environmental conditions leads to the production of secondary metabolites such as mycotoxins and microbial volatile organic compounds (MVOCs). The aim of this study was to characterize MVOC emission profiles of seven toxigenic strains of S. chartarum, isolated from water-damaged buildings, in order to identify unique MVOCs generated during growth on gypsum wallboard and ceiling tile coupons. Inoculated coupons were incubated and monitored for emissions and growth using a closed glass environmental growth chamber maintained at a constant room temperature. Gas samples were collected from the headspace for three to four weeks using Tenax TA tubes.
Most of the MVOCs identified were alcohols, ketones, ethers and esters. The data showed that anisole (methoxybenzene) was emitted from all of the S. chartarum strains tested on both types of substrates. Maximum anisole concentration was detected after seven days of incubation.
MVOCs are suitable markers for fungal identification because they easily diffuse through weak barriers like wallpaper, and could be used for early detection of mold growth in hidden cavities. This study identifies the production of anisole by seven toxigenic strains of Stachybotrys chartarum within a period of one week of growth on gypsum wallboard and ceiling tiles. These data could provide useful information for the future construction of a robust MVOC library for the early detection of this mold.
Journal Article
Testing antimicrobial cleaner efficacy on gypsum wallboard contaminated with Stachybotrys chartarum
by
Webber, Tricia D.
,
Betancourt, Doris A.
,
Foarde, Karin K.
in
Air Pollution, Indoor - prevention & control
,
Antifungal Agents - pharmacology
,
antimicrobial properties
2007
Reducing occupant exposure to indoor mold is the goal of this research, through the efficacy testing of antimicrobial cleaners. Often mold contaminated building materials are not properly removed, but instead surface cleaners are applied in an attempt to alleviate the problem. The efficacy of antimicrobial cleaners to remove, eliminate or control mold growth on surfaces can easily be tested on non-porous surfaces. However, the testing of antimicrobial cleaner efficacy on porous surfaces, such as those found in the indoor environment such as gypsum board can be more complicated and prone to incorrect conclusions regarding residual organisms. The mold Stachybotrys chartarum has been found to be associated with idiopathic pulmonary hemorrhage in infants and has been studied for toxin production and its occurrence in water damaged buildings. Growth of S. chartarum on building materials such as gypsum wallboard has been frequently documented.
Research to control S. chartarum growth using 13 separate antimicrobial cleaners on contaminated gypsum wallboard has been performed in laboratory testing. Popular brands of cleaning products were tested by following directions printed on the product packaging.
A variety of gypsum wallboard surfaces were used to test these cleaning products at high relative humidity. The results indicate differences in antimicrobial efficacy for the six month period of testing.
Results for the six types of GWB surfaces varied extensively. However, three cleaning products exhibited significantly better results than others. Lysol All-Purpose Cleaner-Orange Breeze (full strength) demonstrated results which ranked among the best in five of the six surfaces tested. Both Borax and Orange Glo Multipurpose Degreaser demonstrated results which ranked among the best in four of the six surfaces tested.
The best antimicrobial cleaner to choose is often dependent on the type of surface to be cleaned of S. chartarum contamination. For Plain GWB, no paint, the best cleaners were Borax, Lysol All-Purpose Cleaner-Orange Breeze (full strength), Orange Glo Multipurpose Degreaser, and Fantastik Orange Action.
These results are not meant to endorse the incomplete removal of mold contaminated building materials. However, it is recognized that complete removal may not always be possible and solutions to control mold regrowth may contribute to reduced occupant exposure. Current recommendations of removal and replacement of porous building materials should be followed. It is not the intension of this discussion to endorse any product. Reporting on the performance of these products under the stated conditions was and remains the only purpose.
Journal Article
Microbial volatile organic compound emissions from Stachybotrys chartarumgrowing on gypsum wallboard and ceiling tile
by
Krebs, Ken
,
Moore, Scott A
,
Martin, Shayna M
in
Biological Microscopy
,
Biomedical and Life Sciences
,
Environmental aspects
2013
Background
Stachybotrys chartarum
is a filamentous mold frequently identified among the mycobiota of water-damaged building materials. Growth of
S. chartarum
on suitable substrates and under favorable environmental conditions leads to the production of secondary metabolites such as mycotoxins and microbial volatile organic compounds (MVOCs). The aim of this study was to characterize MVOC emission profiles of seven toxigenic strains of
S. chartarum
, isolated from water-damaged buildings, in order to identify unique MVOCs generated during growth on gypsum wallboard and ceiling tile coupons. Inoculated coupons were incubated and monitored for emissions and growth using a closed glass environmental growth chamber maintained at a constant room temperature. Gas samples were collected from the headspace for three to four weeks using Tenax TA tubes.
Results
Most of the MVOCs identified were alcohols, ketones, ethers and esters. The data showed that anisole (methoxybenzene) was emitted from all of the
S. chartarum
strains tested on both types of substrates. Maximum anisole concentration was detected after seven days of incubation.
Conclusions
MVOCs are suitable markers for fungal identification because they easily diffuse through weak barriers like wallpaper, and could be used for early detection of mold growth in hidden cavities. This study identifies the production of anisole by seven toxigenic strains of
Stachybotrys chartarum
within a period of one week of growth on gypsum wallboard and ceiling tiles. These data could provide useful information for the future construction of a robust MVOC library for the early detection of this mold.
Journal Article
Knowledge, attitudes, and behaviours towards smoking among people with migration experience: a global scoping review
by
Kopp-Heim, Doris
,
Gamba, Magda
,
Held, Lisa M.
in
Attitudes
,
Beliefs, opinions and attitudes
,
Biostatistics
2025
Background
Knowledge, attitudes, and behaviours towards smoking have been extensively researched across diverse populations with migration experience. The objective of this scoping review was to understand the extent, type, and geographical distribution of the published literature on smoking among people with migration experience across the globe.
Methods
We conducted a scoping review using the Joanna Briggs Institute methodology. Supported by two information specialists, we performed a comprehensive literature search (from 2012- 17 January 2024) in five databases, without language or geographic restrictions. The search yielded 8,400 potentially relevant records after deduplication. After title and abstract screening, 305 full texts were included for descriptive analysis and out of these, 25 that covered all three aspects (knowledge, attitudes, and behaviour) were included for content analysis.
Results
The review identified a predominance of quantitative studies (87%), with a smaller proportion of qualitative (12%) and mixed-methods studies (2%). Most studies focused on behavioural prevalence related to tobacco and nicotine product consumption, with 72% addressing behaviours specifically, though only a subset (26%) focused directly on tobacco and/or nicotine use among migrants. Geographical analysis revealed that most of the research originated from high-income countries in particular the USA (
n
= 126), Canada (
n
= 32), and Germany (
n
= 20), with notable gaps in regions with significant migrant populations, such as Saudi Arabia (
n
= 1). Among the 25 KAB-focused studies, data collection was based on surveys (52%), interviews (40%), and focus groups (28%). Findings showed varying knowledge of tobacco harms, shaped by socio-economic status, acculturation, and health literacy. Attitudes were influenced by culture and religion, while smoking behaviours were driven by gender, stress, peer influence, and migration-related pressures. Terminology varied across studies, with inconsistent definitions for key terms \"migrants\" and \"immigrants,\" complicating comparisons between populations and countries. Definitions of tobacco products also varied across studies.
Conclusions
This scoping review reveals significant gaps in research on migrants' knowledge, attitudes, and behaviours towards tobacco and nicotine consumption, including a lack of qualitative studies, inconsistent terminology, and a geographic focus on high-income countries. Addressing these gaps through expanded research in underrepresented regions and standardising terminology is essential for developing culturally relevant public health strategies.
Journal Article
Microbial colonization is required for normal neurobehavioral development in zebrafish
2017
Changes in resident microbiota may have wide-ranging effects on human health. We investigated whether early life microbial disruption alters neurodevelopment and behavior in larval zebrafish. Conventionally colonized, axenic, and axenic larvae colonized at 1 day post fertilization (dpf) were evaluated using a standard locomotor assay. At 10 dpf, axenic zebrafish exhibited hyperactivity compared to conventionalized and conventionally colonized controls. Impairment of host colonization using antibiotics also caused hyperactivity in conventionally colonized larvae. To determine whether there is a developmental requirement for microbial colonization, axenic embryos were serially colonized on 1, 3, 6, or 9 dpf and evaluated on 10 dpf. Normal activity levels were observed in axenic larvae colonized on 1–6 dpf, but not on 9 dpf. Colonization of axenic embryos at 1 dpf with individual bacterial species
Aeromonas veronii
or
Vibrio cholerae
was sufficient to block locomotor hyperactivity at 10 dpf. Exposure to heat-killed bacteria or microbe-associated molecular patterns pam3CSK4 or Poly(I:C) was not sufficient to block hyperactivity in axenic larvae. These data show that microbial colonization during early life is required for normal neurobehavioral development and support the concept that antibiotics and other environmental chemicals may exert neurobehavioral effects via disruption of host-associated microbial communities.
Journal Article
Wildland fire smoke alters the composition, diversity, and potential atmospheric function of microbial life in the aerobiome
2022
The atmosphere contains a diverse reservoir of microbes but the sources and factors contributing to microbial aerosol variability are not well constrained. To advance understanding of microbial emissions in wildfire smoke, we used unmanned aircraft systems to analyze the aerosols above high-intensity forest fires in the western United States. Our results show that samples of the smoke contained ~four-fold higher concentrations of cells (1.02 ± 0.26 × 105 m−3) compared to background air, with 78% of microbes in smoke inferred to be viable. Fivefold higher taxon richness and ~threefold enrichment of ice nucleating particle concentrations in smoke implies that wildfires are an important source of diverse bacteria and fungi as well as meteorologically relevant aerosols. We estimate that such fires emit 3.71 × 1014 microbial cells ha−1 under typical wildfire conditions in western US forests and demonstrate that wildland biomass combustion has a large-scale influence on the local atmospheric microbial assemblages. Given the long-range transport of wildfire smoke emissions, these results expand the concept of a wildfire’s perimeter of biological impact and have implications to biogeography, gene flow, the dispersal of plant, animal, and human pathogens, and meteorology.
Journal Article
Brainstem neurochemical profiles after hospitalisation for COVID-19: a 7T MR spectroscopy study
by
Rua, Catarina
,
McDonald, Rory
,
Newcombe, Virginia F. J.
in
brainstem
,
COVID-19
,
magnetic resonance spectroscopy
2025
Somatic, cognitive and mental health issues have been identified in three-quarters of people 5 months after hospitalisation for severe acute SARS-CoV-2 (COVID-19) infection. The underlying neuroanatomical basis of these symptoms remains unclear, but recent studies suggest a role for altered brainstem physiology. We aimed to test the hypothesis that brainstem neurochemical profiles differ in patients who had been hospitalised for COVID-19 compared to matched controls using 7T magnetic resonance spectroscopy (MRS).
This prospective case-control study recruited 34 individuals who were hospitalised for COVID-19 and 15 healthy controls with no history of COVID-19 infection from two major UK hospitals before vaccines became available. The participants underwent 7T semi-adiabatic localization by adiabatic selective refocusing (sLASER)
H-MRS at the ponto-medullary junction. Water-referenced metabolite concentrations were compared between the patients and controls and correlated with infection severity, as measured by maximum C-reactive protein (CRP
) assay during inpatient admission. Linear mixed modelling was used with a 0.05 significance level.
Spectral quality was high/acceptable in 44/49 participants according to the MRS Consensus criteria. The magnitude of inflammation during patient admission (i.e., CRP
) correlated positively with
-inositol concentration (
= 0.005,
= 0.035), as did patient-reported symptoms (
= -0.564,
= 0.023). However, metabolite concentrations were not significantly different between the patients and controls.
We show the feasibility of assessing brainstem neurochemical profiles using 7T
H-MRS in a multi-centre study. Technical limitations at one site's 7T MRI led to variable repetition times, which limited our statistical power and should be avoided in future studies. Our findings highlight the need for further investigation into the role of neuroinflammation in post-acute COVID-19.
Journal Article
Linking the Physicochemical Properties of Calcined Titania Nanoparticles with Their Biocidal Activity
2016
Titanium dioxide nanoparticles (nTiO2) show biocidal activity when exposed to UV illumination. Modification of their physical properties can expand their photoresponse region toward visible light. In this study, such modification was made through a sol-gel synthesis followed by calcination at a range of temperatures (250–900 °C), generating a series of nTiO2 particles with different crystal phases, sizes, porosities, zeta potentials, and BET surface areas. The unique properties of nTiO2 were linked to their toxicity to the marine bacterium, Vibrio fischeri. A modified “Flash” high-through put assay was used to test the viability of these marine organisms after short term (15–60 min) exposure under visible light only to the individual groups of nTiO2 (500–2000 μg/mL). Linear regression analysis indicated that across all concentrations and time points, high biocidal activity correlated with the amorphous and anatase crystal phases, high BET surface area, high pore volume and small crystal size. The linkage between physicochemistry and nanotoxicity would be helpful for future design of more efficient and sustainable nTiO2.
Journal Article
A simple polymerase chain reaction-sequencing analysis capable of identifying multiple medically relevant filamentous fungal species
by
Betancourt, Doris
,
Dean, Timothy R.
,
Kohan, Michael
in
Aspergillus
,
Aspergillus - genetics
,
Aspergillus - isolation & purification
2006
Due to the accumulating evidence that suggests that numerous unhealthy conditions in the indoor environment are the result of abnormal growth of the filamentous fungi (mold) in and on building surfaces it is necessary to accurately determine the organisms responsible for these maladies and to identify them in an accurate and timely manner. Historically, identification of filamentous fungal (mold) species has been based on morphological characteristics, both macroscopic and microscopic. These methods may often be time consuming and inaccurate, necessitating the development of identification protocols that are rapid, sensitive, and precise. To this end, we have devised a simple PAN-PCR approach which when coupled to cloning and sequencing of the clones allows for the unambiguous identification of multiple fungal organisms. Universal primers are used to amplify ribosomal DNA sequences which are then cloned and transformed into Escherichia coli. Individual clones are then sequenced and individual sequences analyzed and organisms identified. Using this method we were capable of identifying Stachybotrys chartarum, Penicillium purpurogenum, Aspergillus sydowii, and Cladosporium cladosporioides from a mixed culture. This method was found to be rapid, highly specific, easy to perform, and cost effective.
Journal Article
A Simple Polymerase Chain Reaction/Restriction Fragment Length Polymorphism Assay Capable of Identifying Medically Relevant Filamentous Fungi
by
Betancourt, Doris
,
Dean, Timothy R.
,
Kohan, Michael
in
Aspergillus
,
Aspergillus - genetics
,
Biological and medical sciences
2005
Because of the accumulating evidence that suggests that numerous unhealthy conditions in the indoor environment are the result of abnormal growth of the filamentous fungi (mold) in and on building surfaces, it is necessary to accurately reflect the organisms responsible for these maladies and to identify them in precise and timely manner. To this end, we have developed a method that is cost effective, easy to perform, and accurate. We performed a simple polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analysis on multiple members of species known to negatively influence the indoor environment. The genera analyzed were Stachybotrys, Penicillium, Aspergillus, and Cladosporium. Each organism underwent PCR with universal primers that amplified ribosomal sequences generating products from 550 to 600 bp followed by enzymatic digestion with EcoRI, HaeIII, MspI, and HinfI. Our results show that using this combination of restriction enzymes enables the identification of these fungal organisms at the species level.
Journal Article