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Papers by Michael Shiaris

Research paper thumbnail of Effects of polychlorinated biphenyls and environmental biotransformation products on aquatic nitrification

Applied and Environmental Microbiology, Apr 1, 1982

The effects of polychlorinated biphenyls (PCBs) on nitrification were examined for pure cultures ... more The effects of polychlorinated biphenyls (PCBs) on nitrification were examined for pure cultures and natural reservoir samples. PCBs at concentrations greater than 10 ,ug liter-' inhibited nitrification, principally ammonium oxidation, in one of two natural reservoir environments. However, this inhibition could not be reproduced in pure high-cell-density cultures or in previously contaminated reservoir waters. A PCB environmental biotransformation product, p-chlorophenylglyoxylic acid, and p-chloromandelic acid had no effect on nitrification. Polychlorinated biphenyls (PCBs) are recognized as toxic environmental contaminants with near global distribution (16). PCBs are dispersed in the environment principally through industrial use, manufacturing, product and waste disposal, accidential spills, and deliberate discharge. These industrial chemicals, manufactured under the trade name Aroclor (Monsanto Industrial Chemicals Co.) in the United States, are complex mixtures of various chlorinated biphenyl congeners. Because of the environmental distribution, stability of the chlorinated biphenylic ring system (resistance to physical, chemical, and biological degradation), bioaccumulation, toxicity, and mutagenic properties, a federal ban has been placed on their manufacture and use in open-system applications. Evidence indicates that PCBs are subject to microbial biotransformation and metabolism (1, 4, 7, 8, 11, 22, 24, 25; Shiaris and Sayler, Environ. Sci. Technol., in press). We have demonstrated that environmental biotransformation of the lesser chlorinated biphenyls results in the accumulation of chlorobenzoic acids and chlorophenylglyoxylic acid (CPGA) in the environment (Shiaris and Sayler, Environ. Sci. Technol., in press). These chlorinated biotransformation products lack the apparent mutagenicity of the parent PCB residue (Sayler et al., Arch. Environ. Contam. Toxicol., in press). Although PCB toxicity to animal populations and movement in the environment are well doc

Research paper thumbnail of and-Sensitive Fecal Indicator Bacteria inEstuarine Water

Research paper thumbnail of Gold Nanoparticle Paper Immunoassays for Sensing the Presence of Vibrio parahaemolyticus in Oyster Hemolymph

Research paper thumbnail of Detection of CRISPR1-<i>cas1</i> in all <i>Enterococcus</i> strains, by source of isolate

<p>Differences between sources are not significant, P value = 0.6598.</p

Research paper thumbnail of RESEARCH ARTICLE Incidence of Type II CRISPR1-Cas Systems in Enterococcus Is Species-Dependent

CRISPR-Cas systems, which obstruct both viral infection and incorporation of mobile genetic eleme... more CRISPR-Cas systems, which obstruct both viral infection and incorporation of mobile genetic elements by horizontal transfer, are a specific immune response common to pro-karyotes. Antiviral protection by CRISPR-Cas comes at a cost, as horizontally-acquired genes may increase fitness and provide rapid adaptation to habitat change. To date, investi-gations into the prevalence of CRISPR have primarily focused on pathogenic and clinical bacteria, while less is known about CRISPR dynamics in commensal and environmental species. We designed PCR primers and coupled these with DNA sequencing of products to detect and characterize the presence of cas1, a universal CRISPR-associated gene and proxy for the Type II CRISPR1-Cas system, in environmental and non-clinical Enterococ-cus isolates. CRISPR1-cas1 was detected in approximately 33 % of the 275 strains exam-ined, and differences in CRISPR1 carriage between species was significant. Incidence of cas1 in E. hirae was 73%, nearly three times t...

Research paper thumbnail of Replica Plating Method for Estimating Phenanthrene-Utilizing and Phenanthrene-Cometabolizing Microorganisms

Applied and Environmental Microbiology, 1983

A replica plating method was developed for detecting and enumerating phenanthrene-degrading micro... more A replica plating method was developed for detecting and enumerating phenanthrene-degrading microorganisms. The method is designed to discriminate between aquatic organisms that utilize phenanthrene as the sole carbon and energy source and organisms that cometabolize phenanthrene. The method was used to demonstrate that phenanthrene utilizers and phenanthrene cometabolizers coexist in estuarine sediments.

Research paper thumbnail of Size-selective grazing on coastal bacterioplankton by natural assemblages of pigmented flagellates

Research paper thumbnail of Cc: Environmental Protection Agency, Region I (EPA)

Research paper thumbnail of Phenanthrene mineralization along a natural salinity gradient in an Urban Estuary, Boston Harbor, Massachusetts

Research paper thumbnail of M����V��IL��ltllYAOT BIOTRANSFOIMATIOM OF CLIC MOMATIC HYDROCARBONS W ������������ ENVmONMENTS OF COASTAL MASSACHUSETTS

Research paper thumbnail of John Lafleur, Michie Yasuda, M. Shiaris

Research paper thumbnail of Molecular approaches to characterize bacterial communities and populations associated with lobster shell disease

Research paper thumbnail of < i> Enterococcus</i> species composition determined by capillary electrophoresis of the< i> groESL</i> gene spacer region DNA

Research paper thumbnail of Public health implications of sewage applications on wetlands: microbiological aspects

Research paper thumbnail of Microbial ecology of polycyclic aromatic hydrocarbon (PAH) degradation in coastal sediments

Research paper thumbnail of Bioavailability and Biotransformation of Polycyclic Aromatic Hydrocarbons in Benthic Environments of Coastal Massachusetts: Report to the Massachusetts Bays Program

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Research paper thumbnail of Utilization and co-oxidation of aromatic hydrocarbons by estuarine microorganisms

Research paper thumbnail of Optimization of paper-based nanoparticle immunoassays for direct detection of the bacterial pathogen V. parahaemolyticus in oyster hemolymph

Analytical Methods, 2020

The detection of foodborne pathogens is critical for disease control and infection prevention, es... more The detection of foodborne pathogens is critical for disease control and infection prevention, especially in seafood consumed raw or undercooked.

Research paper thumbnail of Comparative survival of antibiotic-resistant and -sensitive fecal indicator bacteria in estuarine water

Applied and Environmental Microbiology, 1987

The survival of antibiotic-resistant and-sensitive strains of Escherichia coli, Enterococcus faec... more The survival of antibiotic-resistant and-sensitive strains of Escherichia coli, Enterococcus faecalis, Enterococcusfaecium, Streptococcus equinus, and two environmental isolates, AP17 and AQ62, was examined in estuarine water. Each strain was rendered resistant to a combination of two antibiotics by serial passage in increasing concentrations of antibiotics. Cultures were incubated in filter-sterilized estuarine water for up to 7 days. Recovery was assessed by examining colony-forming ability on media with and without antibiotics. None of the antibiotic-resistant forms survived longer than its antibiotic-sensitive counterpart in estuarine water. Three of the resistant strains died off more rapidly than the antibiotic-sensitive wild type. Survival of the test bacteria in estuarine water was as follows: sensitive and resistant AQ62, resistant Escherichia coli < sensitive Escherichia coli < resistant AP17 < resistant Enterococcus faecium < sensitive AP17, sensitive and resistant S. equinus < sensitive and resistant Enterococcus faecalis, sensitive Enterococcus faecium. The results supported the suggestion that fecal entercocci may serve as better indicators of fecal pollution than Escherichia coli in marine ecosystems. Moreover, the results indicated that the use of antibiotic-resistant mutants to follow the fate of bacteria in the environment is inappropriate without adequate studies to ensure that resistant and wild-type strains react similarly to environmental stressors.

Research paper thumbnail of Tenax-GC Extraction Technique for Residual Polychlorinated Biphenyl and Polyaromatic Hydrocarbon Analysis in Biodegradation Assays

Applied and Environmental Microbiology, 1980

A rapid Tenax-GC extraction technique has been evaluated for use in conjunction with aqueous biod... more A rapid Tenax-GC extraction technique has been evaluated for use in conjunction with aqueous biodegradation assays for polyaromatic hydrocarbons and polychlorinated biphenyls. The method was quantitatively efficient and reproducible for phenanthrene, but variable and not quantitative for Aroclor 1254 (polychlorinated biphenyls). Aqueous sample volumes and varying concentrations of organic matter influenced polychlorinated biphenyl and polyaromatic hydrocarbon extraction efficiency. Phenanthrene recovery was decreased by soil extract but unaffected by spent bacteriological culture medium. Both types of organic matter caused significant reduction of Aroclor 1254 recovery. Polyaromatic hydrocarbon and polychlorinated biphenyl biodegradation assays, performed with reservoir samples, supported the laboratory evaluation. The study demonstrated the utility of the Tenax-GC extraction technique for phenanthrene analysis in biodegradation assessment; however, Tenax-GC extraction was not appro...

Research paper thumbnail of Effects of polychlorinated biphenyls and environmental biotransformation products on aquatic nitrification

Applied and Environmental Microbiology, Apr 1, 1982

The effects of polychlorinated biphenyls (PCBs) on nitrification were examined for pure cultures ... more The effects of polychlorinated biphenyls (PCBs) on nitrification were examined for pure cultures and natural reservoir samples. PCBs at concentrations greater than 10 ,ug liter-' inhibited nitrification, principally ammonium oxidation, in one of two natural reservoir environments. However, this inhibition could not be reproduced in pure high-cell-density cultures or in previously contaminated reservoir waters. A PCB environmental biotransformation product, p-chlorophenylglyoxylic acid, and p-chloromandelic acid had no effect on nitrification. Polychlorinated biphenyls (PCBs) are recognized as toxic environmental contaminants with near global distribution (16). PCBs are dispersed in the environment principally through industrial use, manufacturing, product and waste disposal, accidential spills, and deliberate discharge. These industrial chemicals, manufactured under the trade name Aroclor (Monsanto Industrial Chemicals Co.) in the United States, are complex mixtures of various chlorinated biphenyl congeners. Because of the environmental distribution, stability of the chlorinated biphenylic ring system (resistance to physical, chemical, and biological degradation), bioaccumulation, toxicity, and mutagenic properties, a federal ban has been placed on their manufacture and use in open-system applications. Evidence indicates that PCBs are subject to microbial biotransformation and metabolism (1, 4, 7, 8, 11, 22, 24, 25; Shiaris and Sayler, Environ. Sci. Technol., in press). We have demonstrated that environmental biotransformation of the lesser chlorinated biphenyls results in the accumulation of chlorobenzoic acids and chlorophenylglyoxylic acid (CPGA) in the environment (Shiaris and Sayler, Environ. Sci. Technol., in press). These chlorinated biotransformation products lack the apparent mutagenicity of the parent PCB residue (Sayler et al., Arch. Environ. Contam. Toxicol., in press). Although PCB toxicity to animal populations and movement in the environment are well doc

Research paper thumbnail of and-Sensitive Fecal Indicator Bacteria inEstuarine Water

Research paper thumbnail of Gold Nanoparticle Paper Immunoassays for Sensing the Presence of Vibrio parahaemolyticus in Oyster Hemolymph

Research paper thumbnail of Detection of CRISPR1-<i>cas1</i> in all <i>Enterococcus</i> strains, by source of isolate

<p>Differences between sources are not significant, P value = 0.6598.</p

Research paper thumbnail of RESEARCH ARTICLE Incidence of Type II CRISPR1-Cas Systems in Enterococcus Is Species-Dependent

CRISPR-Cas systems, which obstruct both viral infection and incorporation of mobile genetic eleme... more CRISPR-Cas systems, which obstruct both viral infection and incorporation of mobile genetic elements by horizontal transfer, are a specific immune response common to pro-karyotes. Antiviral protection by CRISPR-Cas comes at a cost, as horizontally-acquired genes may increase fitness and provide rapid adaptation to habitat change. To date, investi-gations into the prevalence of CRISPR have primarily focused on pathogenic and clinical bacteria, while less is known about CRISPR dynamics in commensal and environmental species. We designed PCR primers and coupled these with DNA sequencing of products to detect and characterize the presence of cas1, a universal CRISPR-associated gene and proxy for the Type II CRISPR1-Cas system, in environmental and non-clinical Enterococ-cus isolates. CRISPR1-cas1 was detected in approximately 33 % of the 275 strains exam-ined, and differences in CRISPR1 carriage between species was significant. Incidence of cas1 in E. hirae was 73%, nearly three times t...

Research paper thumbnail of Replica Plating Method for Estimating Phenanthrene-Utilizing and Phenanthrene-Cometabolizing Microorganisms

Applied and Environmental Microbiology, 1983

A replica plating method was developed for detecting and enumerating phenanthrene-degrading micro... more A replica plating method was developed for detecting and enumerating phenanthrene-degrading microorganisms. The method is designed to discriminate between aquatic organisms that utilize phenanthrene as the sole carbon and energy source and organisms that cometabolize phenanthrene. The method was used to demonstrate that phenanthrene utilizers and phenanthrene cometabolizers coexist in estuarine sediments.

Research paper thumbnail of Size-selective grazing on coastal bacterioplankton by natural assemblages of pigmented flagellates

Research paper thumbnail of Cc: Environmental Protection Agency, Region I (EPA)

Research paper thumbnail of Phenanthrene mineralization along a natural salinity gradient in an Urban Estuary, Boston Harbor, Massachusetts

Research paper thumbnail of M����V��IL��ltllYAOT BIOTRANSFOIMATIOM OF CLIC MOMATIC HYDROCARBONS W ������������ ENVmONMENTS OF COASTAL MASSACHUSETTS

Research paper thumbnail of John Lafleur, Michie Yasuda, M. Shiaris

Research paper thumbnail of Molecular approaches to characterize bacterial communities and populations associated with lobster shell disease

Research paper thumbnail of < i> Enterococcus</i> species composition determined by capillary electrophoresis of the< i> groESL</i> gene spacer region DNA

Research paper thumbnail of Public health implications of sewage applications on wetlands: microbiological aspects

Research paper thumbnail of Microbial ecology of polycyclic aromatic hydrocarbon (PAH) degradation in coastal sediments

Research paper thumbnail of Bioavailability and Biotransformation of Polycyclic Aromatic Hydrocarbons in Benthic Environments of Coastal Massachusetts: Report to the Massachusetts Bays Program

An academic directory and search engine.

Research paper thumbnail of Utilization and co-oxidation of aromatic hydrocarbons by estuarine microorganisms

Research paper thumbnail of Optimization of paper-based nanoparticle immunoassays for direct detection of the bacterial pathogen V. parahaemolyticus in oyster hemolymph

Analytical Methods, 2020

The detection of foodborne pathogens is critical for disease control and infection prevention, es... more The detection of foodborne pathogens is critical for disease control and infection prevention, especially in seafood consumed raw or undercooked.

Research paper thumbnail of Comparative survival of antibiotic-resistant and -sensitive fecal indicator bacteria in estuarine water

Applied and Environmental Microbiology, 1987

The survival of antibiotic-resistant and-sensitive strains of Escherichia coli, Enterococcus faec... more The survival of antibiotic-resistant and-sensitive strains of Escherichia coli, Enterococcus faecalis, Enterococcusfaecium, Streptococcus equinus, and two environmental isolates, AP17 and AQ62, was examined in estuarine water. Each strain was rendered resistant to a combination of two antibiotics by serial passage in increasing concentrations of antibiotics. Cultures were incubated in filter-sterilized estuarine water for up to 7 days. Recovery was assessed by examining colony-forming ability on media with and without antibiotics. None of the antibiotic-resistant forms survived longer than its antibiotic-sensitive counterpart in estuarine water. Three of the resistant strains died off more rapidly than the antibiotic-sensitive wild type. Survival of the test bacteria in estuarine water was as follows: sensitive and resistant AQ62, resistant Escherichia coli < sensitive Escherichia coli < resistant AP17 < resistant Enterococcus faecium < sensitive AP17, sensitive and resistant S. equinus < sensitive and resistant Enterococcus faecalis, sensitive Enterococcus faecium. The results supported the suggestion that fecal entercocci may serve as better indicators of fecal pollution than Escherichia coli in marine ecosystems. Moreover, the results indicated that the use of antibiotic-resistant mutants to follow the fate of bacteria in the environment is inappropriate without adequate studies to ensure that resistant and wild-type strains react similarly to environmental stressors.

Research paper thumbnail of Tenax-GC Extraction Technique for Residual Polychlorinated Biphenyl and Polyaromatic Hydrocarbon Analysis in Biodegradation Assays

Applied and Environmental Microbiology, 1980

A rapid Tenax-GC extraction technique has been evaluated for use in conjunction with aqueous biod... more A rapid Tenax-GC extraction technique has been evaluated for use in conjunction with aqueous biodegradation assays for polyaromatic hydrocarbons and polychlorinated biphenyls. The method was quantitatively efficient and reproducible for phenanthrene, but variable and not quantitative for Aroclor 1254 (polychlorinated biphenyls). Aqueous sample volumes and varying concentrations of organic matter influenced polychlorinated biphenyl and polyaromatic hydrocarbon extraction efficiency. Phenanthrene recovery was decreased by soil extract but unaffected by spent bacteriological culture medium. Both types of organic matter caused significant reduction of Aroclor 1254 recovery. Polyaromatic hydrocarbon and polychlorinated biphenyl biodegradation assays, performed with reservoir samples, supported the laboratory evaluation. The study demonstrated the utility of the Tenax-GC extraction technique for phenanthrene analysis in biodegradation assessment; however, Tenax-GC extraction was not appro...