Clifford Rice

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Roberto Pisano

Politecnico di Torino

Wladimir Sieveking Elgueta

Pontificia Universidad Catolica de Chile

Suruchi Jamkhedkar

University of Mumbai, India

Derrick Dean

Alabama State University

Ãsa Svenningsen

University of Southern Denmark

Guobao Wei

University of Michigan

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University of Eastern Finland

Pei-jen Lou

National Taiwan University

Douglas Rigney

University of Alabama at Birmingham

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University of Malaya, Malaysia

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Papers by Clifford Rice

Persistence of endothall in aquatic environment as determined by gas-liquid chromatography

Journal of Agricultural and Food Chemistry, 1973

... hydrosoil. ACKNOWLEDGMEST The technical assistance of Robert Lynch, Margaret Lindenberger, an... more

Apoplast redox metabolism: Effect of acetovanillone (apocynin) and acetosyringone, on their co-oxidation and redox properties

Physiological and Molecular Plant Pathology, 2020

Abstract A common response of plant leaves and roots to stress, biotic or abiotic, is the oxidati... more Abstract A common response of plant leaves and roots to stress, biotic or abiotic, is the oxidative burst. In leaves, this results in reactive oxygen species being produced within the apoplast, the space surrounding the responding cells. A second response that occurs in the tobacco apoplast during this period is the production and accumulation of phenolic metabolites. The interaction of these redox active metabolites should have major effects on the redox potential of the apoplast and subsequently affect the outcome of the plant tissue. To begin to understand the effects of these responses on the redox potential, two induced phenolics, acetovanillone (AV) and acetosyringone (AS) were studied in vitro with peroxidase and H2O2, all of which are present in the tobacco apoplast. While both phenolics were observed to be substrates for peroxidase, AV was found to react 10x faster than AS. The oxidation of AV resulted in an increase of the redox potential to a maximum of 0.35 V. The oxidation of AS resulted in an increase to a maximum of 0.55 V. Interestingly, the redox potential was not proportional to the oxidation of either phenolic. It was found that when present together, co-oxidation occurs with the faster acting AV as a catalyst to oxidize AS. This has an immediate effect on the redox potential. The rate of AS oxidation is dependent on the AV concentration and thus so is the redox potential reaching 4.5 V. The results suggest that these phenolics could play a role in the regulation of the apoplast redox potential during the early stages of stress.

Method to Evaluate the Age of Groundwater Inputs to Surface Waters by Determining the Chirality Change of Metolachlor Ethanesulfonic Acid (MESA) Captured on a Polar Organic Chemical Integrative Sampler (POCIS)

Journal of Agricultural and Food Chemistry, 2020

We previously discovered a method to estimate the groundwater mean residence time using the chang... more We previously discovered a method to estimate the groundwater mean residence time using the changes in the enantiomeric ratio of MESA (metolachlor ethane sulfonic acid, (2-[(2-ethyl-6-methylphenyl)(2-methoxy-1-methylethyl)amino]-2-oxoethanesulfonic acid), a metabolite of the herbicide metolachlor. However, many grab samples would be needed for each watershed over an extended period, and this is not practical. Thus, we examined the use of a polar organic chemical integrative sampler (POCIS) deployed for 28 days combined with a modified LC-MS/MS method to provide a time-weighted average of the MESA enantiomeric ratio. POCISs equipped with HLB discs were deployed at five sites across the United States where metolachlor was used before and after 1999 and compared the effectiveness of the POCIS to capture MESA versus grab samples. In addition, an in-situ POCIS sampling rate (Rs) for MESA was calculated (0.15 L/d), the precision of MESA extraction from stored POCIS discs was determined, and the effectiveness of HLB to extract MESA was examined. Finally, using molecular modeling, the influence of the asymmetric carbon of metolachlor degradation on the MESA enantiomeric ratio was predicted to be negligible. Results of this work will be used in projects to discern the groundwater mean residence times, to evaluate the delivery of nitrate-N from groundwater to surface waters under various soil, agronomic, and land use conditions, and to examine the effectiveness of conservation practices.

Separation of Polychlorinated Biphenyls, Chlordane, and p,p'-DDT from Toxaphene by Silicic Acid Column Chromatography

Journal of AOAC INTERNATIONAL, 1978

Small columns of precisely deactivated silicic acid (3 g, 3.3% water) were investigated for separ... more Small columns of precisely deactivated silicic acid (3 g, 3.3% water) were investigated for separating hexachlorobenzene, polychlorinated biphenyls (PCBs), DDE, DDT, and cis- and trans-chlordane from toxaphene. The chlorinated hydrocarbons were eluted from the column in 3 fractions: Fraction 1 (50 ml petroleum ether) contained HCB, PCBs, DDE, and 10-30% o,p'-DDT. If desired, HCB could be separated from PCBs by further dividing fraction 1 into 2 portions, the first 13 ml containing HCB and the next 37 ml containing PCBs and DDE. Fraction 2 (80 ml petroleum ether) contained the chlordanes, p,p'-DDT, and 70–90% o,p'-DDT. Dieldrin and p,p'-DDD were eluted in a third (15 ml dichloromethane) fraction. The percentages of toxaphene eluted in the 3 fractions were approximately 10, 30, and 60%, respectively. Most of the toxaphene components interfering with the analysis of p,p'- DDT were eluted in the third fraction. This procedure has been very helpful in separating and i...

Fluxes of agricultural nitrogen and metolachlor metabolites are highly correlated in a first order stream in Maryland, USA

Science of The Total Environment, 2020

Nitrogen pollution in watersheds containing significant cropland area is generally problematic. C... more Nitrogen pollution in watersheds containing significant cropland area is generally problematic. Conservation practices intended to reduce nitrate-N (NO3--N) export from watersheds are being implemented by many regions without necessary tools to assess effectiveness of these abatement tools. A commonly used herbicide metolachlor degrades in the vadose zone of croplands to form two metabolites (metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOXA)) which are both highly soluble in soils. Study of metabolite fates in a first order watershed provided evidence that transport of these metabolites to stream water is highly correlated to transport of agricultural NO3--N that also forms in the cropland vadose zone. Linear models describing the relationships of stream flux of MESA and MOXA to NO3--N flux generated goodness of fit values of 0.93 and 0.81 respectively. These findings support a conclusion that both MESA and MOXA act as excellent transport analogs of NO3--N and become strongly correlated to agricultural NO3--N leaching from the cropland vadose zone. Moreover, their use as conservative tracers in agricultural watersheds can provide valuable information concerning movement and fate of agricultural nitrogen at watershed scales of observation.

Induction of apoplast phenolics in pepper (Capsicum annuum) leaves in response to pathogenic bacteria

Physiological and Molecular Plant Pathology, 2020

Abstract The objective of this study was to corroborate, in pepper, the response of tobacco to in... more Abstract The objective of this study was to corroborate, in pepper, the response of tobacco to induce apoplast phenolics upon bacterial inoculation. Leaves of Bell peppers (Capsicum annuum), 6–8 weeks old, were inoculated with bacteria and analyzed for apoplast phenolics after different periods of incubation. Pseudomonas syringae pv. tabacci, 108 cfu ml−1, induced numerous phenolics to accumulate in the leaf apoplast after 24 h. UPLC-UV chromatograms revealed about 15 UV-peaks, some containing several components. Using this bacterial isolate, it was found that all the fully developed leaves on a single plant had a similar phenolic response based on magnitude and composition of the phenolics. Between plants, the phenolic composition was also similar, although there was more variability. The magnitude of response was proportional to the bacterial concentration between 105-108 cfu ml−1. Plants inoculated with water or P. fluorescens, a saprophyte, had a negligible response. When pepper plants were inoculated with different bacterial pathogens, P. s. pv. tomato and pv. syringae, there were differences in the magnitude and composition of the phenolics after 24 h. A time course showed that phenolic accumulation was underway by 7 h and appeared to peak by 24 h. The bacterial induction of apoplast phenolics in pepper, described here, corroborates the similar response previously described for tobacco. The preliminary characterization by UPLC-UV/MS suggests the apoplast phenolics found in pepper are structurally different from those in tobacco. However, the similar timing and location of the responses in both plants would suggest that their roles in the plant bacterial interaction are also similar. Further investigation of the redox and bioactivity properties of these apoplast phenolics is needed.

Anaerobic digestion reduces veterinary ionophore lasalocid in dairy manure

DESALINATION AND WATER TREATMENT, 2018

Combined extraction method for metabolomic and PLFA analysis of soil

Applied Soil Ecology, 2018

Abstract Characterization of the soil metabolome contributes to our understanding of how soil mic... more Abstract Characterization of the soil metabolome contributes to our understanding of how soil microbial community functions, central to sustainable agriculture, are impacted by agricultural management practices. The aim of this study was to refine the Bligh-Dyer 2-phase extraction method, commonly used in soil phospholipid fatty acid analysis (PLFA), to enhance soil metabolite detection and use this refined method to look at the impact of specific crop production factors on the soil metabolome. We modified the Bligh-Dyer 2-phase extraction method through the addition of the volatile salt, 0.25 M ammonium bicarbonate, to increase the number of metabolites extracted from soil. A greenhouse pot study with three soil types and two crop species was conducted, and soil metabolites extracted using this refined Bligh-Dyer 2-phase extraction, to determine the impact of soil type and crop species treatments on the soil metabolome. Numerous amino acids, carbohydrates, TCA cycle intermediates, and fatty acids as well as the potentially inhibitory compounds ferulic acid, caffeic acid, oxalic acid, and quinic acid differed significantly with treatment. At the onset of the greenhouse pot experiment the three soil types differed significantly in metabolite composition and at the end of the 6 week experiment both soil and crop had significant impacts on the soil metabolome. Substituting the volatile salt 0.25 M ammonium bicarbonate for phosphate buffer in the Bligh-Dyer 2-phase extraction did not significantly impact PLFA analysis of the three soils. The extract was also found to be useable in lipidomic analysis. We conclude that the addition of this volatile salt to the Bligh-Dyer 2-phase extraction provided an effective method for analysis of both the soil metabolome and soil PLFA.

The fate and effect of monensin during anaerobic digestion of dairy manure under mesophilic conditions

PLOS ONE, 2018

There is growing concern about residual antibiotics and feed additives in the manure of treated a... more There is growing concern about residual antibiotics and feed additives in the manure of treated animals because of the effects of these residues in the environment. Monensin is the most widely used ionophore coccidiostat in the U.S. The objective of this study was to determine the fate and effect of monensin during the anaerobic digestion of dairy manure. Duplicate plug flow field-scale digesters were operated using non-amended dairy manure and dairy manure amended with monensin to 1 and 10 mg/L for 56 days at 30˚C at an organic loading rate of 1.4 kg VS/m 3-d and 17-day hydraulic retention time. Results showed that monensin was reduced approximately 70% during anaerobic digestion. Methane production from digesters using manure amended with 1 mg/L monensin was comparable to that from digesters operated without added monensin. However, digesters using manure amended with 10 mg/L monensin yielded 75% less methane than digesters using manure without added monensin. These results suggest that anaerobic digestion is an effective treatment for reducing, but not eliminating, monensin in dairy manure. Monensin did not reduce methane production at concentrations expected in dairy manure at recommended dosage rates.

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Insights into the metabolism and behaviour of Varroa destructor mites from analysis of their waste excretions

Parasitology, 2018

Varroa destructor mites (Acari: Varroidae) are harmful ectoparasites of Apis mellifera honey bees... more Varroa destructor mites (Acari: Varroidae) are harmful ectoparasites of Apis mellifera honey bees. Female foundresses of wax-capped pupal host cells and their daughters feed on host fluids from open wounds on the host's integument. Details of V. destructor mite nutrition are forthcoming, and little is known about the potential physical effects on hosts from mite feeding. Chemical analysis of waste excretions can infer details of animals’ nutrition. Here, chemical analysis by high-performance liquid chromatography/mass spectrometry (HPLC-MS/MS) of mite excretions showed that the purine content of V. destructor waste consists of guanine with traces of hypoxanthine. Traces of uric acid and caffeine were also detected. Concentrations of guanine attenuated over time and excretions collected from senescing mites did not contain detectable guanine. Non-reproducing individual female mites maintained in vitro, housed in gelatin capsules and provided a honey bee pupa, deposited an average...

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Fate of four phthalate plasticizers under various wastewater treatment processes

Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering, Jan 18, 2018

The fate of four phthalate plasticizers during wastewater treatment processes at six different wa... more The fate of four phthalate plasticizers during wastewater treatment processes at six different wastewater treatment plants (WWTPs) was investigated. Concentrations of benzyl butyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DiNP), and diisodecyl phthalate (DiDP) were determined prior to either aerobic or anaerobic (conventional and advanced) treatment, after treatment, and in final, dewatered solids. Despite their elevated use worldwide, the fate of DiNP and DiDP during wastewater treatment have not been well characterized. DEHP was readily degraded during aerobic treatments while anaerobic digestion resulted in either no significant change in concentrations or an increase in concentration, in the case of more advanced anaerobic processes (thermal hydrolysis pretreatment and a two-phase acid/gas process). Impacts of the various treatment systems on DiNP, DiDP, and BBP concentrations were more varied - anaerobic digestion led to significant decreases, in...

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Fate of triclocarban in agricultural soils after biosolid applications

Environmental science and pollution research international, Jan 13, 2017

Triclocarban [N-(4-chlorophenyl)-N-(3,4-dichlorophenyl) urea] (TCC) is an antimicrobial agent uti... more Triclocarban [N-(4-chlorophenyl)-N-(3,4-dichlorophenyl) urea] (TCC) is an antimicrobial agent utilized in a variety of consumer products. It is commonly released into domestic wastewaters and upon treatment, it is known to accumulate in biosolids. This study examines the occurrence of TCC in biosolids and its long-term fate in biosolid-treated soils. TCC levels in the biosolids from a large waste water treatment plant (WWTP) over 2 years showed little variability at 18,800 ± 700 ng g(-1) dry wt. (mean ± SEM). Surface soil samples (top 10 cm) were collected from 26 commercial farms located in northern VA, US that had received biosolid applications from the WWTP. Samples were grouped as farms receiving no biosolids, farms with a single biosolid application, and those receiving multiple biosolid applications from 1992 to 2006. Our results illustrate that TCC soil residues remained years after biosolid application. The two most important parameters controlling TCC topsoil concentrations...

Degradation of triclosan and triclocarban and formation of transformation products in activated sludge using benchtop bioreactors

Environmental research, Jan 30, 2017

Benchtop bioreactors were run aerobically with activated sludge samples collected from a large mu... more Benchtop bioreactors were run aerobically with activated sludge samples collected from a large municipal wastewater treatment plant (WWTP) to understand how increased hydraulic retention time (HRT), sludge retention time (SRT), and varying treatment temperatures (21°C and 30°C) impact concentrations of the endocrine disrupting antimicrobials triclosan (TCS), triclocarban (TCC), and their transformation products. Samples from the reactors were collected periodically over a 122-196h period and the solid and liquid fraction were separately quantitated for TCS, TCC, and methyltriclosan (MeTCS) and scanned qualitatively for six other transformation products. Results indicated that TCS, TCC and MeTCS were predominately associated with the solids fraction of the activated sludge with only nominal concentrations in the liquids fraction. TCS was degraded in the solids fraction, with increased rates at 30°C (-0.0224 ± 0.007h(-1)) when compared to reactors run at 21°C (- 0.0170 ± 0.003h(-1)). ...

Influence of thermal hydrolysis-anaerobic digestion treatment of wastewater solids on concentrations of triclosan, triclocarban, and their transformation products in biosolids

Chemosphere, 2017

The growing concern worldwide regarding the presence of emerging contaminants in biosolids calls ... more The growing concern worldwide regarding the presence of emerging contaminants in biosolids calls for a better understanding of how different treatment technologies at water resource recovery facilities (WRRFs) can influence concentrations prior to biosolids land application. This study focuses on the influence of solids treatment via the Cambi Thermal Hydrolysis Process™ in conjunction with anaerobic digestion (TH-AD) on concentrations of triclosan (TCS), triclocarban (TCC), and their transformation products in biosolids and sludges. Concentrations of the target analytes in biosolids from the TH-AD process (Class A), sludges from the individual TH-AD treatment steps, and limed biosolids (Class B) from the same WRRF were compared. TCC concentrations were significantly lower in Class A biosolids than those in the Class B product-a removal that occurred during thermal hydrolysis. Concentrations of TCS, methyl triclosan, and 2,4-dichlorophenol, conversely, increased during anaerobic digestion, leading to significantly higher concentrations of these compounds in Class A

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The effect of composting on the persistence of four ionophores in dairy manure and poultry litter

Waste management (New York, N.Y.), 2016

Manure composting is a well-described approach for stabilization of nutrients and reduction of pa... more Manure composting is a well-described approach for stabilization of nutrients and reduction of pathogens and odors. Although composting studies have shown that thermophilic temperatures and aerobic conditions can increase removal rates of selected antibiotics, comparable information is lacking for many other compounds in untreated or composted manure. The objective of this study was to determine the relative effectiveness of composting conditions to reduce concentrations of four widely used ionophore feed supplements in dairy manure and poultry litter. Replicate aliquots of fresh poultry litter and dairy manure were amended with monensin, lasalocid, salinomycin, or amprolium to 10mgkg(-1)DW. Non-amended and amended dairy manure and poultry litter aliquots were incubated at 22, 45, 55, or 65°C under moist, aerobic conditions. Residue concentrations were determined from aliquots removed after 1, 2, 4, 6, 8, and 12weeks. Results suggest that the effectiveness of composting for contamin...

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Post-harvest Tissue Preparation to Minimize Glucosinolate Loss from Raphanus sativus

ITC-CMA partnership and data needs for alkylphenols and ethoxylates

Society of Environmental Toxicology and Chemistry Annual Meeting Abstract Book, 1996

Induction of redox sensitive extracellular phenolics during plant–bacterial interactions

Physiological and Molecular Plant Pathology, 2005

This study focuses on the transient and complex nature of phenolics that accumulate in the extrac... more This study focuses on the transient and complex nature of phenolics that accumulate in the extracellular environment of plant suspension cells during the first few hours of the interaction between these plant cells and bacterial pathogens. Using suspension cells of Nicotiana tabacum we identified four acetophenones and four hydroxycinnamic acid amides that accumulate in this extracellular environment. Treatment of the suspension cells with isolates of the plant pathogen Pseudomonas syringae or heat-killed bacteria increased elicitation of extracellular phenolics and changed the composition of the compounds that accumulated. These phenolics were sensitive to oxidative stress; when suspension cells were treated with bacterial strains or elicitors that triggered an oxidative burst, these phenolics were oxidized and depleted for the duration of the burst. The qualitative and quantitative makeup of phenolics produced by N. tabacum suspensions was also affected by plant cell age and density. To our knowledge, this is the first study that closely follows the kinetics of individual extracellular phenolic compounds and the concurrent oxidative stress during the first few hours of a plant-bacterial interaction.

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Structural and Thermodynamic Considerations in the Isomeric Conversion of Endosulfan

Pesticide and Nitrate-N Behavior in Groundwater Within a Riparian Wetland

ABSTRACT

Persistence of endothall in aquatic environment as determined by gas-liquid chromatography

Journal of Agricultural and Food Chemistry, 1973

... hydrosoil. ACKNOWLEDGMEST The technical assistance of Robert Lynch, Margaret Lindenberger, an... more

Apoplast redox metabolism: Effect of acetovanillone (apocynin) and acetosyringone, on their co-oxidation and redox properties

Physiological and Molecular Plant Pathology, 2020