Tamara Marsh - Academia.edu (original) (raw)

Papers by Tamara Marsh

Comprehensive Psychology, 2014

A laboratory investigating and monitoring the eff ect of exposing a microbe to a virus was added ... more A laboratory investigating and monitoring the eff ect of exposing a microbe to a virus was added to a Health Psychology class. Students in the Health Psychology class received a class lectures on "Microbiology Laboratory Techniques" and "Concepts in Immunology." Students then participated in a two-class meeting laboratory procedure to track changes in a microbe exposed to a virus. Student perceptions of their learning satisfaction were increased from pre to post laboratory measures. Learning lessons from the teaching method are presented.

Bios, Mar 1, 2015

Abstract. Invasion of Alliaria petiolata (garlic mustard) has become increasingly problematic, as... more Abstract. Invasion of Alliaria petiolata (garlic mustard) has become increasingly problematic, as it has disrupted the native ecosystem of the forest understory throughout most of the United States. A key element of garlic mustard invasion is the production of two compounds that have been shown to be inhibitory at relatively low concentrations, allyl-isothiocyanate (AITC) and benzyl-isothiocyanate (BITC). The current study utilizes Minimum Inhibitory Concentration tests to assess the effect of AITC, BITC, and AITC and BITC in combination on the soil microbial community across a gradient of invasion severity: from uninvaded, moderately invaded, and heavily invaded sites. It is hypothesized that prior history of garlic mustard invasion, chemical treatment, previous chemical exposure and chemical concentration will all influence microbial growth. Results showed that invasion history and chemical condition significantly influenced microbial growth for initially exposed trials, but only chemical condition influenced the growth of previously exposed trials. Microbial growth in initial trials was significantly higher than growth in previously exposed trials, and increasing chemical concentration correlated to decreased microbial growth. A better understanding of the relationship between garlic mustard and the general soil microbial community will enable the design of more efficient and site-specific evaluation and treatment techniques, as well as provide insights into the impact that invasion has on ecosystem processes.

American Journal of Undergraduate Research, 2015

Native American tribes with bountiful harvests. Today it is widely recognized that this associate... more Native American tribes with bountiful harvests. Today it is widely recognized that this associated intercropping system derives much of its success from symbiotic bacteria (e.g. Rhizobium). These bacteria colonize the roots of leguminous plants, allowing them to fix atmospheric nitrogen into ammonia. However, the effect of this intercropping practice on the microbial community, independent of the effect of the symbiotic nitrogen-fixing bacteria, is not well understood. Therefore, a study was designed to model the effects of simultaneously intercropping bean and corn on the abundance of aerobic heterotrophic, free-living nitrogen-fixing, and symbiotic nitrogen-fixing bacteria, as well as plant growth and fecundity markers. In parallel, the benefits mediated by rhizobia were evaluated by inoculating a duplicate set of treatments with N-Dure, a rhizobia-containing inoculum. Native American varieties of pole-bean (Phaseolus vulgaris L.) and corn (Zea mays mays L.) were planted in monocu...

Most ethnic foods and cooking practices have incorporated the use of spices and other food additi... more Most ethnic foods and cooking practices have incorporated the use of spices and other food additives. Many common spices have crossed cultural boundaries and appear in multiple ethnic cuisines. Recent studies have demonstrated that many of these ingredients possess antimicrobial properties against common food spoilage microorganisms. We developed a laboratory exercise that promotes the use of scientific methodology to evaluate the effectiveness of salsa components at inhibiting the growth of undesirable microorganisms. Tomato, onion, garlic, cilantro, and jalapeño were tested for antimicrobial properties against a representative fungus, Saccharomyces cerevisiae, and the common food spoilage bacteria Staphylococcus aureus, Bacillus cereus, and Escherichia coli. Each component was ethanol extracted and a modification of the Kirby-Bauer method of antimicrobial sensitivity was employed. Garlic demonstrated the greatest inhibitory effects against all organisms tested. Onion demonstrated ...

Microbes in Applied Research, 2012

Journal of Microbiology & Biology Education

Course-based undergraduate research experiences (CUREs) help fulfill the recommendation of Vision... more Course-based undergraduate research experiences (CUREs) help fulfill the recommendation of Vision and Change for biology curricula to focus on key concepts and skills to better prepare students for careers in the sciences. However, the COVID-19 pandemic has forced many schools to move instruction online, highlighting the dearth of resources available for offering a CURE for introductory biology outside of the traditional laboratory-based setting.

Geomicrobiology Journal, 2000

Aquifer sediments from Norman, Oklahoma, were used to study the potential for microbial reduction... more Aquifer sediments from Norman, Oklahoma, were used to study the potential for microbial reduction of Cr(VI) to Cr(III). Black, clay-like sediments rapidly reduced Cr(VI) in both autoclaved and viable microcosms, indicating an abiotic mechanism. Lightcolored sandy sediments slowly reduced Cr(VI) only in viable microcosms, indicating a biological process. Cr(VI) reduction in these sediments had a pH optimum of 6.8 and

Applied and Environmental Microbiology, 2001

Biological Cr(VI) reduction was studied in anaerobic sediments from an aquifer in Norman, Okla. M... more Biological Cr(VI) reduction was studied in anaerobic sediments from an aquifer in Norman, Okla. Microcosms containing sediment and mineral medium were amended with various electron donors to determine those most important for biological Cr(VI) reduction. Cr(VI) (about 340 μM) was reduced with endogenous substrates (no donor), or acetate was added. The addition of formate, hydrogen, and glucose stimulated Cr(VI) reduction compared with reduction in unamended controls. From these sediments, an anaerobic Cr(VI)-utilizing enrichment was obtained that was dependent upon hydrogen for both growth and Cr(VI) reduction. No methane was produced by the enrichment, which reduced about 750 μM Cr(VI) in less than six days. The dissolved hydrogen concentration was used as an indicator of the terminal electron accepting process occurring in the sediments. Microcosms with sediments, groundwater, and chromate metabolized hydrogen to a concentration below the detection limits of the mercury vapor gas ...

Journal of Microbiology & Biology Education

Journal of Microbiology & Biology Education

The introduction of Vision and Change by AAAS and the recommendation that biology departments ame... more The introduction of Vision and Change by AAAS and the recommendation that biology departments amend their curricula to focus on key concepts and skills necessary for graduates have led to a re-envisioning of introductory curricula across the nation. Many of the “standard” biology text books have realigned their focus with Vision and Change, while new texts have emerged that completely revise how we teach introductory biology majors. One such textbook is Integrating Concepts in Biology (ICB), by Campbell, Heyer, and Paradise. Many departments, including ours, have adopted this text as a novel way to teach biology majors, focusing on active learning, the scientific method, and specifically, understanding data. However, with all of these revisions to biology textbooks, there have been no revisions or insights into corresponding labs for a typical 1-year introductory course sequence. Here, we provide a description of our 1-year lab sequence, emphasizing the scientific method and novel r...

Comprehensive Psychology, 2014

A laboratory investigating and monitoring the eff ect of exposing a microbe to a virus was added ... more A laboratory investigating and monitoring the eff ect of exposing a microbe to a virus was added to a Health Psychology class. Students in the Health Psychology class received a class lectures on "Microbiology Laboratory Techniques" and "Concepts in Immunology." Students then participated in a two-class meeting laboratory procedure to track changes in a microbe exposed to a virus. Student perceptions of their learning satisfaction were increased from pre to post laboratory measures. Learning lessons from the teaching method are presented.

Journal of College Science Teaching, 2014

Journal of Microbiology & Biology Education, 2015

In response to the publication of Vision and Change, the biology department at Elmhurst College r... more In response to the publication of Vision and Change, the biology department at Elmhurst College revised our curriculum to better prepare students for a career in science with the addition of various writing assignments in every course. One commonality among all of the assignments is the ability to comprehend and critically evaluate scientific literature to determine relevancy and possible future research. Several previous reports have analyzed specific methodologies to improve student comprehension of scientific writing and critical thinking skills, yet none of these examined student growth over an undergraduate career. In this study, we hypothesized upper-level students would be better able to comprehend and critically analyze scientific literature than introductory biology majors. Biology students enrolled in an introductory (200-level), mid- (300-level), or late-career (400-level) course were tasked with reading and responding to questions regarding a common scientific article an...

Journal of Microbiology & Biology Education, 2009

Most ethnic foods and cooking practices have incorporated the use of spices and other food additi... more Most ethnic foods and cooking practices have incorporated the use of spices and other food additives. Many common spices have crossed cultural boundaries and appear in multiple ethnic cuisines. Recent studies have demonstrated that many of these ingredients possess antimicrobial properties against common food spoilage microorganisms. We developed a laboratory exercise that promotes the use of scientific methodology to evaluate the effectiveness of salsa components at inhibiting the growth of undesirable microorganisms. Tomato, onion, garlic, cilantro, and jalapeño were tested for antimicrobial properties against a representative fungus, Saccharomyces cerevisiae , and the common food spoilage bacteria Staphylococcus aureus , Bacillus cereus , and Escherichia coli . Each component was ethanol extracted and a modification of the Kirby-Bauer method of antimicrobial sensitivity was employed. Garlic demonstrated the greatest inhibitory effects against all organisms tested. Onion demonstra...

Applied and Environmental Microbiology, 2010

Massively parallel sequencing has provided a more affordable and high-throughput method to study ... more Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 μM and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree ...

Applied and Environmental Microbiology, 2010

Massively parallel sequencing has provided a more affordable and high-throughput method to study ... more Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 μM and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree ...

Maize, bean, and squash have been intercropped for thousands of years, sustaining Maya Indians an... more Maize, bean, and squash have been intercropped for thousands of years, sustaining Maya Indians and Native American tribes with bountiful harvests. Today it is widely recognized that this associated inter-cropping system derives much of its success from symbiotic bacteria (e.g. Rhizobium). These bacteria colonize the roots of leguminous plants, allowing them to fix atmospheric nitrogen into ammonia. However, the effect of this intercropping practice on the microbial community, independent of the effect of the symbiotic nitrogen-fixing bacteria, is not well understood. Therefore, a study was designed to model the effects of simultaneously intercropping bean and corn on the abundance of aerobic heterotrophic, free-living nitrogen-fixing, and symbiotic nitrogen-fixing bacteria, as well as plant growth and fecundity markers. In parallel, the benefits mediated by rhizobia were evaluated by inoculating a duplicate set of treatments with N-Dure, a rhizobia-containing inoculum. Native American varieties of pole-bean (Phaseolus vulgaris L.) and corn (Zea mays mays L.) were planted in monoculture and biculture treatments. All cultivations were maintained under greenhouse conditions for 52 days with daily watering and no additional fertilizer or microbial amendments. Although a significant increase in weight per plant was noted for the inoculated biculture when compared to either the inoculated bean or corn monocultures (p 0.05), the abundance of heterotrophic and free-living nitrogen-fixing bacteria did not show a significant change from the related controls, with or without inoculation. However, symbiotic nitrogen-fixing bacteria, as measured by root nodulation, increased significantly (p 0.05) for the inoculated biculture and single planting. Thus, these data confirm that corn benefited from this associated intercropping system as shown by an increase in plant biomass that can be attributed to Rhizobium. However, neither the legume-bacteria symbiotic relationship nor the increase in plant biodiversity resulting from this intercropping practice appears to have had significant effects on the abundance of the two common soil-associated bacterial groups evaluated, though further research would be necessary to fully assess the changes to heterotrophic bacterial diversity at the species level.

Comprehensive Psychology, 2014

A laboratory investigating and monitoring the eff ect of exposing a microbe to a virus was added ... more A laboratory investigating and monitoring the eff ect of exposing a microbe to a virus was added to a Health Psychology class. Students in the Health Psychology class received a class lectures on "Microbiology Laboratory Techniques" and "Concepts in Immunology." Students then participated in a two-class meeting laboratory procedure to track changes in a microbe exposed to a virus. Student perceptions of their learning satisfaction were increased from pre to post laboratory measures. Learning lessons from the teaching method are presented.

Bios, Mar 1, 2015

Abstract. Invasion of Alliaria petiolata (garlic mustard) has become increasingly problematic, as... more Abstract. Invasion of Alliaria petiolata (garlic mustard) has become increasingly problematic, as it has disrupted the native ecosystem of the forest understory throughout most of the United States. A key element of garlic mustard invasion is the production of two compounds that have been shown to be inhibitory at relatively low concentrations, allyl-isothiocyanate (AITC) and benzyl-isothiocyanate (BITC). The current study utilizes Minimum Inhibitory Concentration tests to assess the effect of AITC, BITC, and AITC and BITC in combination on the soil microbial community across a gradient of invasion severity: from uninvaded, moderately invaded, and heavily invaded sites. It is hypothesized that prior history of garlic mustard invasion, chemical treatment, previous chemical exposure and chemical concentration will all influence microbial growth. Results showed that invasion history and chemical condition significantly influenced microbial growth for initially exposed trials, but only chemical condition influenced the growth of previously exposed trials. Microbial growth in initial trials was significantly higher than growth in previously exposed trials, and increasing chemical concentration correlated to decreased microbial growth. A better understanding of the relationship between garlic mustard and the general soil microbial community will enable the design of more efficient and site-specific evaluation and treatment techniques, as well as provide insights into the impact that invasion has on ecosystem processes.

American Journal of Undergraduate Research, 2015

Native American tribes with bountiful harvests. Today it is widely recognized that this associate... more Native American tribes with bountiful harvests. Today it is widely recognized that this associated intercropping system derives much of its success from symbiotic bacteria (e.g. Rhizobium). These bacteria colonize the roots of leguminous plants, allowing them to fix atmospheric nitrogen into ammonia. However, the effect of this intercropping practice on the microbial community, independent of the effect of the symbiotic nitrogen-fixing bacteria, is not well understood. Therefore, a study was designed to model the effects of simultaneously intercropping bean and corn on the abundance of aerobic heterotrophic, free-living nitrogen-fixing, and symbiotic nitrogen-fixing bacteria, as well as plant growth and fecundity markers. In parallel, the benefits mediated by rhizobia were evaluated by inoculating a duplicate set of treatments with N-Dure, a rhizobia-containing inoculum. Native American varieties of pole-bean (Phaseolus vulgaris L.) and corn (Zea mays mays L.) were planted in monocu...

Most ethnic foods and cooking practices have incorporated the use of spices and other food additi... more Most ethnic foods and cooking practices have incorporated the use of spices and other food additives. Many common spices have crossed cultural boundaries and appear in multiple ethnic cuisines. Recent studies have demonstrated that many of these ingredients possess antimicrobial properties against common food spoilage microorganisms. We developed a laboratory exercise that promotes the use of scientific methodology to evaluate the effectiveness of salsa components at inhibiting the growth of undesirable microorganisms. Tomato, onion, garlic, cilantro, and jalapeño were tested for antimicrobial properties against a representative fungus, Saccharomyces cerevisiae, and the common food spoilage bacteria Staphylococcus aureus, Bacillus cereus, and Escherichia coli. Each component was ethanol extracted and a modification of the Kirby-Bauer method of antimicrobial sensitivity was employed. Garlic demonstrated the greatest inhibitory effects against all organisms tested. Onion demonstrated ...

Microbes in Applied Research, 2012

Journal of Microbiology & Biology Education

Course-based undergraduate research experiences (CUREs) help fulfill the recommendation of Vision... more Course-based undergraduate research experiences (CUREs) help fulfill the recommendation of Vision and Change for biology curricula to focus on key concepts and skills to better prepare students for careers in the sciences. However, the COVID-19 pandemic has forced many schools to move instruction online, highlighting the dearth of resources available for offering a CURE for introductory biology outside of the traditional laboratory-based setting.

Geomicrobiology Journal, 2000

Aquifer sediments from Norman, Oklahoma, were used to study the potential for microbial reduction... more Aquifer sediments from Norman, Oklahoma, were used to study the potential for microbial reduction of Cr(VI) to Cr(III). Black, clay-like sediments rapidly reduced Cr(VI) in both autoclaved and viable microcosms, indicating an abiotic mechanism. Lightcolored sandy sediments slowly reduced Cr(VI) only in viable microcosms, indicating a biological process. Cr(VI) reduction in these sediments had a pH optimum of 6.8 and

Applied and Environmental Microbiology, 2001

Biological Cr(VI) reduction was studied in anaerobic sediments from an aquifer in Norman, Okla. M... more Biological Cr(VI) reduction was studied in anaerobic sediments from an aquifer in Norman, Okla. Microcosms containing sediment and mineral medium were amended with various electron donors to determine those most important for biological Cr(VI) reduction. Cr(VI) (about 340 μM) was reduced with endogenous substrates (no donor), or acetate was added. The addition of formate, hydrogen, and glucose stimulated Cr(VI) reduction compared with reduction in unamended controls. From these sediments, an anaerobic Cr(VI)-utilizing enrichment was obtained that was dependent upon hydrogen for both growth and Cr(VI) reduction. No methane was produced by the enrichment, which reduced about 750 μM Cr(VI) in less than six days. The dissolved hydrogen concentration was used as an indicator of the terminal electron accepting process occurring in the sediments. Microcosms with sediments, groundwater, and chromate metabolized hydrogen to a concentration below the detection limits of the mercury vapor gas ...

Journal of Microbiology & Biology Education

Journal of Microbiology & Biology Education

The introduction of Vision and Change by AAAS and the recommendation that biology departments ame... more The introduction of Vision and Change by AAAS and the recommendation that biology departments amend their curricula to focus on key concepts and skills necessary for graduates have led to a re-envisioning of introductory curricula across the nation. Many of the “standard” biology text books have realigned their focus with Vision and Change, while new texts have emerged that completely revise how we teach introductory biology majors. One such textbook is Integrating Concepts in Biology (ICB), by Campbell, Heyer, and Paradise. Many departments, including ours, have adopted this text as a novel way to teach biology majors, focusing on active learning, the scientific method, and specifically, understanding data. However, with all of these revisions to biology textbooks, there have been no revisions or insights into corresponding labs for a typical 1-year introductory course sequence. Here, we provide a description of our 1-year lab sequence, emphasizing the scientific method and novel r...

Comprehensive Psychology, 2014

A laboratory investigating and monitoring the eff ect of exposing a microbe to a virus was added ... more A laboratory investigating and monitoring the eff ect of exposing a microbe to a virus was added to a Health Psychology class. Students in the Health Psychology class received a class lectures on "Microbiology Laboratory Techniques" and "Concepts in Immunology." Students then participated in a two-class meeting laboratory procedure to track changes in a microbe exposed to a virus. Student perceptions of their learning satisfaction were increased from pre to post laboratory measures. Learning lessons from the teaching method are presented.

Journal of College Science Teaching, 2014

Journal of Microbiology & Biology Education, 2015

In response to the publication of Vision and Change, the biology department at Elmhurst College r... more In response to the publication of Vision and Change, the biology department at Elmhurst College revised our curriculum to better prepare students for a career in science with the addition of various writing assignments in every course. One commonality among all of the assignments is the ability to comprehend and critically evaluate scientific literature to determine relevancy and possible future research. Several previous reports have analyzed specific methodologies to improve student comprehension of scientific writing and critical thinking skills, yet none of these examined student growth over an undergraduate career. In this study, we hypothesized upper-level students would be better able to comprehend and critically analyze scientific literature than introductory biology majors. Biology students enrolled in an introductory (200-level), mid- (300-level), or late-career (400-level) course were tasked with reading and responding to questions regarding a common scientific article an...

Journal of Microbiology & Biology Education, 2009

Most ethnic foods and cooking practices have incorporated the use of spices and other food additi... more Most ethnic foods and cooking practices have incorporated the use of spices and other food additives. Many common spices have crossed cultural boundaries and appear in multiple ethnic cuisines. Recent studies have demonstrated that many of these ingredients possess antimicrobial properties against common food spoilage microorganisms. We developed a laboratory exercise that promotes the use of scientific methodology to evaluate the effectiveness of salsa components at inhibiting the growth of undesirable microorganisms. Tomato, onion, garlic, cilantro, and jalapeño were tested for antimicrobial properties against a representative fungus, Saccharomyces cerevisiae , and the common food spoilage bacteria Staphylococcus aureus , Bacillus cereus , and Escherichia coli . Each component was ethanol extracted and a modification of the Kirby-Bauer method of antimicrobial sensitivity was employed. Garlic demonstrated the greatest inhibitory effects against all organisms tested. Onion demonstra...

Applied and Environmental Microbiology, 2010

Massively parallel sequencing has provided a more affordable and high-throughput method to study ... more Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 μM and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree ...

Applied and Environmental Microbiology, 2010

Massively parallel sequencing has provided a more affordable and high-throughput method to study ... more Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 μM and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree ...

Maize, bean, and squash have been intercropped for thousands of years, sustaining Maya Indians an... more Maize, bean, and squash have been intercropped for thousands of years, sustaining Maya Indians and Native American tribes with bountiful harvests. Today it is widely recognized that this associated inter-cropping system derives much of its success from symbiotic bacteria (e.g. Rhizobium). These bacteria colonize the roots of leguminous plants, allowing them to fix atmospheric nitrogen into ammonia. However, the effect of this intercropping practice on the microbial community, independent of the effect of the symbiotic nitrogen-fixing bacteria, is not well understood. Therefore, a study was designed to model the effects of simultaneously intercropping bean and corn on the abundance of aerobic heterotrophic, free-living nitrogen-fixing, and symbiotic nitrogen-fixing bacteria, as well as plant growth and fecundity markers. In parallel, the benefits mediated by rhizobia were evaluated by inoculating a duplicate set of treatments with N-Dure, a rhizobia-containing inoculum. Native American varieties of pole-bean (Phaseolus vulgaris L.) and corn (Zea mays mays L.) were planted in monoculture and biculture treatments. All cultivations were maintained under greenhouse conditions for 52 days with daily watering and no additional fertilizer or microbial amendments. Although a significant increase in weight per plant was noted for the inoculated biculture when compared to either the inoculated bean or corn monocultures (p 0.05), the abundance of heterotrophic and free-living nitrogen-fixing bacteria did not show a significant change from the related controls, with or without inoculation. However, symbiotic nitrogen-fixing bacteria, as measured by root nodulation, increased significantly (p 0.05) for the inoculated biculture and single planting. Thus, these data confirm that corn benefited from this associated intercropping system as shown by an increase in plant biomass that can be attributed to Rhizobium. However, neither the legume-bacteria symbiotic relationship nor the increase in plant biodiversity resulting from this intercropping practice appears to have had significant effects on the abundance of the two common soil-associated bacterial groups evaluated, though further research would be necessary to fully assess the changes to heterotrophic bacterial diversity at the species level.