Gregory Mueller | Northwestern University (original) (raw)
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Papers by Gregory Mueller
Veterinary and human toxicology
A new program, Fungal Identification System (FIS) was introduced in POISINDEX (PI) in 1991. We st... more A new program, Fungal Identification System (FIS) was introduced in POISINDEX (PI) in 1991. We studied the accuracy of this program compared to the traditional method of consulting an expert mycologist and also the utility of FIS for the certified specialist in poison information (CSPI) and the emergency department personnel. Fifteen samples were obtained from a Chicago area forest preserve and immediately identified by a CSPI using FIS from PI of summer-fall 1991. The samples were then refrigerated overnight and identified the following morning by a PhD mycologist, using standard mycological identification techniques (SMIT). Another group of 18 mushrooms were collected in August 1992 from rural southwestern Michigan and identified by FIS and SMIT after refrigeration overnight. In 4 cases the mycologist used both SMIT and FIS to identify the mushrooms. Identification by FIS did not match SMIT in 27 of 31 samples (1 was discarded and 1 was identified by FIS but not identified by SMIT). In 2 of 4 cases where the mycologist used FIS, a different answer was obtained from that obtained by the CSPI; however, these were still incorrect identifications. Four types of problems using FIS have been identified which can lead to erroneous results; these are the use of multipart questions, emphasis on color over less variable characteristics, questions which do not account for variability in morphology, and problems which arise from the sequence of questions. These points need to be addressed before FIS can be used as a safe basis for clinical recommendations.
Molecular Phylogenetics and Evolution, 2004
The lichen-forming genus Porpidia (Porpidiaceae, Ascomycota) provides excellent opportunities for... more The lichen-forming genus Porpidia (Porpidiaceae, Ascomycota) provides excellent opportunities for evolutionary, reproductive, and ecological studies of crustose epilithic lichen symbioses. However, despite the fact that the genus itself seemed to be clearly delimited, the group was thought to be a hopeless case with regard to intrageneric relationships and species delimitations due to apparently rampant homoplasy throughout most character systems. Contrary to the situation for non-molecular data, a robust and generally well-resolved phylogeny was recovered based on DNA-sequence data. Separate and combined analyses of nuclear ribosomal RNA large subunit and nuclear beta-tubulin gene fragments were performed using maximum parsimony, maximum likelihood, and Bayesian approaches. Branch support was estimated using non-parametic bootstrapping and posterior probabilities, while monophyly of a priori defined groups was tested using posterior probabilities. The results reveal a highly supported "Porpidia sensu lato," however, Porpidia itself is not monophyletic. Several smaller genera of the Porpidiaceae and probably the large genus Lecidea (Lecideaceae) are nested within the group. Most taxa analyzed fall into one of four major subgroups within Porpidia s.l., though the basal relationships among these subgroups could not be supported. This phylogeny will make it possible to re-evaluate morphological and chemical characters in the group, and to conduct detailed studies of species delimitations within the monophyletic subgroups.
Biodiversity of Fungi, 2004
Mycologia, 1999
Boletus flavoniger, B. lychnipes, B. neoregius, and B. quercophilus are newly described from Quer... more Boletus flavoniger, B. lychnipes, B. neoregius, and B. quercophilus are newly described from Quercus dominated forests of Costa Rica. Boletus firmus, a misunderstood taxon from eastern North America, is reported for the first time in Costa Rica. Boletus neoregius and B. quercophilus have been found in a number of sites throughout the country, while B. flavoniger, B. lychnipes, and B. firmus appear restricted to unique localities. Their exact distribution outside of Costa Rica is unknown, but they may be expected in other oak-dominated forests in Central America and northern South America.
Science of The Total Environment, 1998
This study explored the differences in metal uptake in sporocarps of ectomycorrhizae-forming fung... more This study explored the differences in metal uptake in sporocarps of ectomycorrhizae-forming fungi relative to 1 Ž . Ž . fungal species; 2 collection location; 3 differential metal uptake and variation within single-species, single-area Ž . populations; and 4 mobile metal content of soil substrate for the fungi. In addition, this study examined levels of some of the lanthanides in these mushrooms, as lanthanide uptake in higher fungi has not been quantified to date. In Ž 1995 and 1996, sporocarps from three species of ectomycorrhizal fungi Amanita fla¨orubescens, Amanita rubescens, . Ž and Russula pectinatoides were collected from Cowles Bog, Indiana Dunes National Lakeshore near an industrial . Ž . area and the Palos forest preserves near a residential area . Soil was also collected from the Cowles Bog plots; metals were extracted from the soil, either with local Lake Michigan water or with nitric acid. These two extractions were meant to simulate the natural soil equilibrium concentrations of soluble metals and the maximum possible effects of any fungal chelating chemicals, respectively. An inductively coupled plasma mass spectrometer was used to analyze soil extracts and nitric acid digests of whole sporocarps for the target analytes. The metals found at elevated Ž . Ž levels in the mushrooms included four of environmental interest Ag, Cd, Ba, and Pb and three lanthanides La, Ce, . and Nd . Significant differences in uptake of metals were observed between A. rubescens and R. pectinatoides, while A. rubescens and A. fla¨orubescens were not significantly different. With regard to location, more cadmium was found in Cowles Bog collections of A. rubescens, while Palos forest A. rubescens had more of the lanthanides and barium. Significant specimen-to-specimen variation occurred in all populations examined. Correlation analysis between pairs of trace elements within each sporocarp population revealed strong positive correlations between the lanthanides. Sporocarps concentrated more metal than was made available by the lake water extraction of soil and less metal than was made available by the nitric acid extraction of soil. ᮊ
Nordic Journal of Botany, 1991
... mostly 3-20 pm diam, thin-walled, hyaline to light yel-lowish brown or vinaceous brown; cells... more ... mostly 3-20 pm diam, thin-walled, hyaline to light yel-lowish brown or vinaceous brown; cells long, barrel-shaped. ... Basidiospores globose to oblong and echinulate or very elongate and very finely roughened, occasionally un-iguttulate, hyaline; hilar appendage prominent, trun ...
New Phytologist, 2008
How nitrogen (N) deposition impacts ectomycorrhizal (EM) fungal communities has been little studi... more How nitrogen (N) deposition impacts ectomycorrhizal (EM) fungal communities has been little studied in deciduous forests or across spatial scales. Here, it was tested whether N addition decreases species richness and shifts species composition across spatial scales in temperate deciduous oak forests. • Combined molecular (terminal restriction fragment length polymorphism (T-RFLP), sequencing) and morphological approaches were used to measure EM fungal operational taxon unit (OTU) richness, community structure and composition at the spatial scale of the root, soil core and forest during a 3-yr N fertilization experiment in Quercus-dominated forests near Chicago, IL, USA. • In N treatments, significantly lower OTU richness at the largest but not smaller spatial scales and a different community structure were detected. The effects of N appeared to be immediate, not cumulative. Ordination indicated the composition of EM fungal communities was determined by forest site and N fertilization. • The EM fungi responded to a N increase that was low compared with other fertilization studies, suggesting that moderate increases in N deposition can affect EM fungal communities at larger spatial scales in temperate deciduous ecosystems. While responses at large spatial scales indicate that environmental factors can drive changes in these communities, untangling the impacts of abiotic from biotic factors remain limited by detection issues.
Mycotaxon, 2010
The Hawaiian mushroom Rhodocollybia laulaha was selected as a model to investigate patterns of ge... more The Hawaiian mushroom Rhodocollybia laulaha was selected as a model to investigate patterns of gene flow between geographically isolated fungal populations from ecologically and bioclimatically varied sites. Its morphology (distinctive when compared to other members of the genus) and affinity for endemic Hawaiian forest suggested that it was endemic to Hawaii. However, speculation as to its closest non-Hawaiian relative and its overall placement within the genus was based on mostly anecdotal evidence. The present morphological and genetic research identifies a wellsupported clade comprising R. laulaha individuals from across the Hawaiian Islands, reveals R. lignitilis (described in 2004 from the Neotropics) to be conspecific with R. laulaha, and identifies R. unakensis from Texas as a putative sister taxon. Different possible historical scenarios are discussed regarding the migration and establishment of R laulaha ancestors between the Americas and Hawaii. Rhodocollybia lignitilis is synonymized with R. laulaha, and Marasmius clavipes is transferred to Rhodocollybia.
Mycoscience, 2013
Keywords: Asia Ectomycorrhizae Fungal Systematics Himalayas ITS a b s t r a c t Species of Laccar... more Keywords: Asia Ectomycorrhizae Fungal Systematics Himalayas ITS a b s t r a c t Species of Laccaria are described from the eastern Himalayas, in the Xizang Autonomous Region of China, more commonly known as Tibet. Specimens were collected during several expeditions over a 12-year time span. Nuclear ribosomal internally transcribed spacer regions 1 and 2 including and 5.8S (ITS) as well as the 5' end of the large subunit (28S) sequence data were generated for 22 specimens from Tibet and analyzed in a dataset of 115 Laccaria samples. The results documented seven species from this region, five of which represent currently undescribed species. The taxonomy of Tibetan Laccaria is discussed, five new species are proposed, and an artificial key that includes extralimital species from Asia is provided.
Veterinary and human toxicology
A new program, Fungal Identification System (FIS) was introduced in POISINDEX (PI) in 1991. We st... more A new program, Fungal Identification System (FIS) was introduced in POISINDEX (PI) in 1991. We studied the accuracy of this program compared to the traditional method of consulting an expert mycologist and also the utility of FIS for the certified specialist in poison information (CSPI) and the emergency department personnel. Fifteen samples were obtained from a Chicago area forest preserve and immediately identified by a CSPI using FIS from PI of summer-fall 1991. The samples were then refrigerated overnight and identified the following morning by a PhD mycologist, using standard mycological identification techniques (SMIT). Another group of 18 mushrooms were collected in August 1992 from rural southwestern Michigan and identified by FIS and SMIT after refrigeration overnight. In 4 cases the mycologist used both SMIT and FIS to identify the mushrooms. Identification by FIS did not match SMIT in 27 of 31 samples (1 was discarded and 1 was identified by FIS but not identified by SMIT). In 2 of 4 cases where the mycologist used FIS, a different answer was obtained from that obtained by the CSPI; however, these were still incorrect identifications. Four types of problems using FIS have been identified which can lead to erroneous results; these are the use of multipart questions, emphasis on color over less variable characteristics, questions which do not account for variability in morphology, and problems which arise from the sequence of questions. These points need to be addressed before FIS can be used as a safe basis for clinical recommendations.
Molecular Phylogenetics and Evolution, 2004
The lichen-forming genus Porpidia (Porpidiaceae, Ascomycota) provides excellent opportunities for... more The lichen-forming genus Porpidia (Porpidiaceae, Ascomycota) provides excellent opportunities for evolutionary, reproductive, and ecological studies of crustose epilithic lichen symbioses. However, despite the fact that the genus itself seemed to be clearly delimited, the group was thought to be a hopeless case with regard to intrageneric relationships and species delimitations due to apparently rampant homoplasy throughout most character systems. Contrary to the situation for non-molecular data, a robust and generally well-resolved phylogeny was recovered based on DNA-sequence data. Separate and combined analyses of nuclear ribosomal RNA large subunit and nuclear beta-tubulin gene fragments were performed using maximum parsimony, maximum likelihood, and Bayesian approaches. Branch support was estimated using non-parametic bootstrapping and posterior probabilities, while monophyly of a priori defined groups was tested using posterior probabilities. The results reveal a highly supported &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;Porpidia sensu lato,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; however, Porpidia itself is not monophyletic. Several smaller genera of the Porpidiaceae and probably the large genus Lecidea (Lecideaceae) are nested within the group. Most taxa analyzed fall into one of four major subgroups within Porpidia s.l., though the basal relationships among these subgroups could not be supported. This phylogeny will make it possible to re-evaluate morphological and chemical characters in the group, and to conduct detailed studies of species delimitations within the monophyletic subgroups.
Biodiversity of Fungi, 2004
Mycologia, 1999
Boletus flavoniger, B. lychnipes, B. neoregius, and B. quercophilus are newly described from Quer... more Boletus flavoniger, B. lychnipes, B. neoregius, and B. quercophilus are newly described from Quercus dominated forests of Costa Rica. Boletus firmus, a misunderstood taxon from eastern North America, is reported for the first time in Costa Rica. Boletus neoregius and B. quercophilus have been found in a number of sites throughout the country, while B. flavoniger, B. lychnipes, and B. firmus appear restricted to unique localities. Their exact distribution outside of Costa Rica is unknown, but they may be expected in other oak-dominated forests in Central America and northern South America.
Science of The Total Environment, 1998
This study explored the differences in metal uptake in sporocarps of ectomycorrhizae-forming fung... more This study explored the differences in metal uptake in sporocarps of ectomycorrhizae-forming fungi relative to 1 Ž . Ž . fungal species; 2 collection location; 3 differential metal uptake and variation within single-species, single-area Ž . populations; and 4 mobile metal content of soil substrate for the fungi. In addition, this study examined levels of some of the lanthanides in these mushrooms, as lanthanide uptake in higher fungi has not been quantified to date. In Ž 1995 and 1996, sporocarps from three species of ectomycorrhizal fungi Amanita fla¨orubescens, Amanita rubescens, . Ž and Russula pectinatoides were collected from Cowles Bog, Indiana Dunes National Lakeshore near an industrial . Ž . area and the Palos forest preserves near a residential area . Soil was also collected from the Cowles Bog plots; metals were extracted from the soil, either with local Lake Michigan water or with nitric acid. These two extractions were meant to simulate the natural soil equilibrium concentrations of soluble metals and the maximum possible effects of any fungal chelating chemicals, respectively. An inductively coupled plasma mass spectrometer was used to analyze soil extracts and nitric acid digests of whole sporocarps for the target analytes. The metals found at elevated Ž . Ž levels in the mushrooms included four of environmental interest Ag, Cd, Ba, and Pb and three lanthanides La, Ce, . and Nd . Significant differences in uptake of metals were observed between A. rubescens and R. pectinatoides, while A. rubescens and A. fla¨orubescens were not significantly different. With regard to location, more cadmium was found in Cowles Bog collections of A. rubescens, while Palos forest A. rubescens had more of the lanthanides and barium. Significant specimen-to-specimen variation occurred in all populations examined. Correlation analysis between pairs of trace elements within each sporocarp population revealed strong positive correlations between the lanthanides. Sporocarps concentrated more metal than was made available by the lake water extraction of soil and less metal than was made available by the nitric acid extraction of soil. ᮊ
Nordic Journal of Botany, 1991
... mostly 3-20 pm diam, thin-walled, hyaline to light yel-lowish brown or vinaceous brown; cells... more ... mostly 3-20 pm diam, thin-walled, hyaline to light yel-lowish brown or vinaceous brown; cells long, barrel-shaped. ... Basidiospores globose to oblong and echinulate or very elongate and very finely roughened, occasionally un-iguttulate, hyaline; hilar appendage prominent, trun ...
New Phytologist, 2008
How nitrogen (N) deposition impacts ectomycorrhizal (EM) fungal communities has been little studi... more How nitrogen (N) deposition impacts ectomycorrhizal (EM) fungal communities has been little studied in deciduous forests or across spatial scales. Here, it was tested whether N addition decreases species richness and shifts species composition across spatial scales in temperate deciduous oak forests. • Combined molecular (terminal restriction fragment length polymorphism (T-RFLP), sequencing) and morphological approaches were used to measure EM fungal operational taxon unit (OTU) richness, community structure and composition at the spatial scale of the root, soil core and forest during a 3-yr N fertilization experiment in Quercus-dominated forests near Chicago, IL, USA. • In N treatments, significantly lower OTU richness at the largest but not smaller spatial scales and a different community structure were detected. The effects of N appeared to be immediate, not cumulative. Ordination indicated the composition of EM fungal communities was determined by forest site and N fertilization. • The EM fungi responded to a N increase that was low compared with other fertilization studies, suggesting that moderate increases in N deposition can affect EM fungal communities at larger spatial scales in temperate deciduous ecosystems. While responses at large spatial scales indicate that environmental factors can drive changes in these communities, untangling the impacts of abiotic from biotic factors remain limited by detection issues.
Mycotaxon, 2010
The Hawaiian mushroom Rhodocollybia laulaha was selected as a model to investigate patterns of ge... more The Hawaiian mushroom Rhodocollybia laulaha was selected as a model to investigate patterns of gene flow between geographically isolated fungal populations from ecologically and bioclimatically varied sites. Its morphology (distinctive when compared to other members of the genus) and affinity for endemic Hawaiian forest suggested that it was endemic to Hawaii. However, speculation as to its closest non-Hawaiian relative and its overall placement within the genus was based on mostly anecdotal evidence. The present morphological and genetic research identifies a wellsupported clade comprising R. laulaha individuals from across the Hawaiian Islands, reveals R. lignitilis (described in 2004 from the Neotropics) to be conspecific with R. laulaha, and identifies R. unakensis from Texas as a putative sister taxon. Different possible historical scenarios are discussed regarding the migration and establishment of R laulaha ancestors between the Americas and Hawaii. Rhodocollybia lignitilis is synonymized with R. laulaha, and Marasmius clavipes is transferred to Rhodocollybia.
Mycoscience, 2013
Keywords: Asia Ectomycorrhizae Fungal Systematics Himalayas ITS a b s t r a c t Species of Laccar... more Keywords: Asia Ectomycorrhizae Fungal Systematics Himalayas ITS a b s t r a c t Species of Laccaria are described from the eastern Himalayas, in the Xizang Autonomous Region of China, more commonly known as Tibet. Specimens were collected during several expeditions over a 12-year time span. Nuclear ribosomal internally transcribed spacer regions 1 and 2 including and 5.8S (ITS) as well as the 5' end of the large subunit (28S) sequence data were generated for 22 specimens from Tibet and analyzed in a dataset of 115 Laccaria samples. The results documented seven species from this region, five of which represent currently undescribed species. The taxonomy of Tibetan Laccaria is discussed, five new species are proposed, and an artificial key that includes extralimital species from Asia is provided.