Publications by authors named "James L Smith"

81 Publications

Paper spray ionization-high-resolution mass spectrometry (PSI-HRMS) of peroxide explosives in biological matrices.

Anal Bioanal Chem 2021 May 15;413(11):3069-3079. Epub 2021 Mar 15.

Department of Chemistry, University of Rhode Island, 140 Flagg Rd, Kingston, RI, 02881, USA.

Mitigation of the peroxide explosive threat, specifically triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD), is a priority among the law enforcement community, as scientists and canine (K9) units are constantly working to improve detection. We propose the use of paper spray ionization-high-resolution mass spectrometry (PSI-HRMS) for detection of peroxide explosives in biological matrices. Occurrence of peroxide explosives and/or their metabolites in biological samples, obtained from urine or blood tests, give scientific evidence of peroxide explosives exposure. PSI-HRMS promote analysis of samples in situ by eliminating laborious sample preparation steps. However, it increases matrix background issues, which were overcome by the formation of multiple alkali metal adducts with the peroxide explosives. Multiple ion formation increases confidence when identifying these peroxide explosives in direct sample analysis. Our previous work examined aspects of TATP metabolism. Herein, we investigate the excretion of a TATP glucuronide conjugate in the urine of bomb-sniffing dogs and demonstrate its detection using PSI from the in vivo sample.
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http://dx.doi.org/10.1007/s00216-021-03244-4DOI Listing
May 2021

metabolism of HMTD and blood stability and toxicity of peroxide explosives (TATP and HMTD) in canines and humans.

Xenobiotica 2021 Apr 20;51(4):394-403. Epub 2021 Jan 20.

Department of Chemistry, University of Rhode Island, Kingston, RI, USA.

Triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) are prominent explosive threats. Mitigation of peroxide explosives is a priority among the law enforcement community, with canine (K9) units being trained to recognise the scent of peroxide explosives. Herein, the metabolism, blood distribution, and toxicity of peroxide explosives are investigated.HMTD metabolism studies in liver microsomes identified two potential metabolites, tetramethylene diperoxide diamine alcohol aldehyde (TMDDAA) and tetramethylene peroxide diamine dialcohol dialdehyde (TMPDDD).Blood stability studies in dogs and humans showed that HMTD was rapidly degraded, whereas TATP remained for at least one week.Toxicity studies in dog and human hepatocytes indicated minimum cell death for both TATP and HMTD.
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http://dx.doi.org/10.1080/00498254.2021.1874563DOI Listing
April 2021

Weights of gaur () and banteng () killed by tigers in Thailand.

Ecol Evol 2020 Jun 16;10(11):5152-5159. Epub 2020 Apr 16.

Department of Fisheries, Wildlife, and Conservation Biology University of Minnesota Minneapolis MN USA.

The primary prey of tigers across much of South-East Asia has been depleted, reducing the ability of already limited habitat to support tigers. To better understand the extent to which two of the largest prey species, gaur () and banteng (), contribute to the tiger's diet, we estimated the average size of these species killed by tigers. This information is needed to more accurately calculate biomass of these species in the tiger's diet and to devise strategies to increase tiger carrying capacity where habitat is fragmented and limited in west-central Thailand. We used temporally clumped locations of 24 satellite radio-collared tigers to identify their kill sites and obtained mandibles from 82 gaur and 79 banteng. Kills were aged by teeth eruption sequence, sectioning the M1 molar and counting cementum annuli. Of all gaur killed, 45.2% were adults; of all banteng killed, 55.7% were adults. The average weight of banteng killed was 423.9 kg, which was similar to the 397.9 kg average weight for gaur. The mean weight of both prey species is 3.5-4.5 times greater than the predicted 1:1 preferred prey to predator ratio. In the absence of medium-sized prey, killing these larger animals may be especially critical for female tigers provisioning nearly independent young when male offspring are already larger than the mother. This is the first study to present data on the average weights of gaur and banteng killed in South-East Asia, and these results suggest that these are key prey species to target in tiger prey recovery efforts.
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http://dx.doi.org/10.1002/ece3.6268DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7297748PMC
June 2020

Binge Drinking among Economically Disadvantaged African American Older Adults with Diabetes.

Behav Sci (Basel) 2019 Sep 11;9(9). Epub 2019 Sep 11.

Departments of Family Medicine, College of Medicine, Charles R Drew University of Medicine and Science, 118th St, Los Angeles, CA 90059, USA.

This study investigated the effect of demographic, socioeconomic, and psychological factors as well as the role of health determinants on alcohol consumption and binge drinking among economically disadvantaged African American older adults with type 2 diabetes mellites (T2DM). This survey recruited 231 African Americans who were older adults (age 65+ years) and had T2DM. Participants were selected from economically disadvantaged areas of South Los Angeles. A structured face-to-face interview was conducted to collect data on demographic factors, objective and subjective socioeconomic status (SES) including education and financial difficulty, living arrangement, marital status, health, and drinking behaviors (drinking and binge drinking). Age, gender, living alone, pain, comorbid conditions, and smoking were associated with drinking/binge drinking. Male gender, pain, and being a smoker were associated with higher odds of drinking/binge drinking, while individuals with more comorbid medical conditions had lower odds of binge drinking. In economically constrained urban environments, gender, pain, and smoking but not age, SES, depression, and health may predict binge drinking for African American older adults with T2DM. African Americans older adult men with T2DM with comorbid pain should be screened for binge drinking.
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http://dx.doi.org/10.3390/bs9090097DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6769764PMC
September 2019

Chronic Respiratory Disease and Health-Related Quality of Life of African American Older Adults in an Economically Disadvantaged Area of Los Angeles.

Int J Environ Res Public Health 2019 05 17;16(10). Epub 2019 May 17.

Departments of Family Medicine, College of Medicine, Charles R Drew University of Medicine and Science, Los Angeles, CA 90059, USA.

Most of the attention of policy makers, program planners, clinicians, and researchers in the area of physical health disparities among African American older adults has been traditionally focused on cardiometabolic disease and cancer. Among a long list of chronic medical conditions, chronic respiratory conditions (CRCs), such as asthma, chronic bronchitis, and emphysema, have received less attention. This study investigated whether CRCs contribute to physical and mental health-related quality of life (HRQoL) of African American older adults who live in economically disadvantaged urban areas, and whether these effects are due to demographic factors, socioeconomic status (SES), health behaviors, and comorbid medical and mental conditions. This community-based study recruited 617 African American older adults (age ≥ 65 years) from Service Planning Areas (SPA) 6, an economically disadvantaged area in South Los Angeles. Structured face-to-face interviews were used to collect data on demographic factors (age and gender), SES (educational attainment and financial difficulty), living arrangements, marital status, health behaviors (cigarette smoking and alcohol drinking), health (CRC, number of comorbid medical conditions, depressive symptoms, and pain intensity), and physical and mental HRQoL (Physical and Mental Component Summary Scores; PCS and MCS; SF-12). Linear regressions were used to analyze the data. The presence of CRCs was associated with lower PCS and MCS in bivariate analysis. The association between CRCs and PCS remained significant above and beyond all confounders. However, the association between CRCs and MCS disappeared after controlling for confounders. For African American older adults living in economically disadvantaged urban areas, CRCs contribute to poor physical HRQoL. Evaluation and treatment of CRCs in African American older adults may be a strategy for reduction of disparities in HRQoL in this population. As smoking is the major modifiable risk factor for CRCs, there is a need to increase accessibility of smoking cessation programs in economically disadvantaged urban areas. More research is needed on the types, management, and prognosis of CRCs such as asthma, chronic bronchitis, and emphysema in African American older adults who reside in low-income and resource limited urban areas.
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http://dx.doi.org/10.3390/ijerph16101756DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6571607PMC
May 2019

Cigarette Smoking among Economically Disadvantaged African-American Older Adults in South Los Angeles: Gender Differences.

Int J Environ Res Public Health 2019 04 4;16(7). Epub 2019 Apr 4.

Department of Family Medicine, College of Medicine, Charles R Drew University of Medicine and Science, Los Angeles, CA 90059, USA.

The current study aims to explore gender differences in the risk of cigarette smoking among African-American (AA) older adults who live in economically disadvantaged urban areas of southern Los Angeles. This cross-sectional study enrolled 576 older AA adults (age range between 65 and 96 years) who were residing in Service Planning Area 6 (SPA 6), one of the most economically challenged areas in southern Los Angeles. All participants had cardiometabolic disease (CMD). Data were collected using structured face-to-face interviews. Demographic factors (age and gender), socioeconomic status (educational attainment and financial difficulty), health (number of comorbid medical conditions and depressive symptoms), and health behaviors (current alcohol drinking and current smoking) were measured. Logistic regressions were used to analyze the data without and with interaction terms between gender and current drinking, depressive symptoms, and financial difficulty. AA men reported more smoking than AA women (25.3% versus 9.3%; < 0.05). Drinking showed a stronger association with smoking for AA men than AA women. Depressive symptoms, however, showed stronger effects on smoking for AA women than AA men. Gender did not interact with financial difficulty with regard to current smoking. As AA older men and women differ in psychological and behavioral determinants of cigarette smoking, gender-specific smoking cessation interventions for AA older adults who live in economically deprived urban areas may be more successful than interventions and programs that do not consider gender differences in determinants of smoking. Gender-tailored smoking cessation programs that address drinking for AA men and depression for AA women may help reduce the burden of smoking in AA older adults in economically disadvantaged urban areas. Given the non-random sampling, there is a need for replication of these findings in future studies.
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http://dx.doi.org/10.3390/ijerph16071208DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6480530PMC
April 2019

Emergency Department Utilization among Underserved African American Older Adults in South Los Angeles.

Int J Environ Res Public Health 2019 04 2;16(7). Epub 2019 Apr 2.

Department of Family Medicine, Charles R. Drew University of Medicine and Science (CDU), Los Angeles, CA 90059, USA.

Using the Andersen's Behavioral Model of Health Services Use, we explored social, behavioral, and health factors that are associated with emergency department (ED) utilization among underserved African American (AA) older adults in one of the most economically disadvantaged urban areas in South Los Angeles, California. This cross-sectional study recruited a convenience sample of 609 non-institutionalized AA older adults (age ≥ 65 years) from South Los Angeles, California. Participants were interviewed for demographic factors, self-rated health, chronic medication conditions (CMCs), pain, depressive symptoms, access to care, and continuity of care. Outcomes included 1 or 2+ ED visits in the last 12 months. Polynomial regression was used for data analysis. Almost 41% of participants were treated at an ED during the last 12 months. In all, 27% of participants attended an ED once and 14% two or more times. Half of those with 6+ chronic conditions reported being treated at an ED once; one quarter at least twice. Factors that predicted no ED visit were male gender (OR = 0.50, 95% CI = 0.29-0.85), higher continuity of medical care (OR = 1.55, 95% CI = 1.04-2.31), individuals with two CMCs or less (OR = 2.61 (1.03-6.59), second tertile of pain severity (OR = 2.80, 95% CI = 1.36-5.73). Factors that predicted only one ED visit were male gender (OR = 0.45, 95% CI = 0.25-0.82), higher continuity of medical care (OR = 1.39, 95% CI = 1.01-2.15) and second tertile of pain severity (OR = 2.42, 95% CI = 1.13-5.19). This study documented that a lack of continuity of care for individuals with multiple chronic conditions leads to a higher rate of ED presentations. The results are significant given that ED visits may contribute to health disparities among AA older adults. Future research should examine whether case management decreases ED utilization among underserved AA older adults with multiple chronic conditions and/or severe pain. To explore the generalizability of these findings, the study should be repeated in other settings.
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http://dx.doi.org/10.3390/ijerph16071175DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6479964PMC
April 2019

Impact of prey occupancy and other ecological and anthropogenic factors on tiger distribution in Thailand's western forest complex.

Ecol Evol 2019 03 18;9(5):2449-2458. Epub 2019 Feb 18.

University of Minnesota Saint Paul Minnesota.

Despite conservation efforts, large mammals such as tigers () and their main prey, gaur (), banteng (), and sambar (), are highly threatened and declining across their entire range. The only large viable source population of tigers in mainland Southeast Asia occurs in Thailand's Western Forest Complex (WEFCOM), an approximately 19,000 km landscape of 17 contiguous protected areas.We used an occupancy modeling framework, which accounts for imperfect detection, to identify the factors that affect tiger distribution at the approximate scale of a female tiger's home range, 64 km, and site use at a scale of 1-km. At the larger scale, we estimated the proportion of sites at WEFCOM that were occupied by tigers; at the finer scale, we identified the key variables that influence site-use and developed a predictive distribution map. At both scales, we examined key anthropogenic and ecological factors that help explain tiger distribution and habitat use, including probabilities of gaur, banteng, and sambar occurrence from a companion study.Occupancy estimated at the 64-km scale was primarily influenced by the combined presence of all three large prey species, and 37% or 5,858 km of the landscape was predicted to be occupied by tigers. In contrast, site use estimated at the scale of 1 km was most strongly influenced by the presence of sambar.By modeling occupancy while accounting for imperfect probability of detection, we established reliable benchmark data on the distribution of tigers in WEFCOM. This study also identified factors that limit tiger distributions; which managers can then target to expand tiger distribution and guide recovery elsewhere in Southeast Asia.
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http://dx.doi.org/10.1002/ece3.4845DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6405490PMC
March 2019

Genome-Wide Evolutionary Analysis of Natural History and Adaptation in the World's Tigers.

Curr Biol 2018 12 25;28(23):3840-3849.e6. Epub 2018 Oct 25.

The State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, 100871 Beijing, China. Electronic address:

No other species attracts more international resources, public attention, and protracted controversies over its intraspecific taxonomy than the tiger (Panthera tigris) [1, 2]. Today, fewer than 4,000 free-ranging tigers survive, covering only 7% of their historical range, and debates persist over whether they comprise six, five, or two subspecies [3-6]. The lack of consensus over the number of tiger subspecies has partially hindered the global effort to recover the species from the brink of extinction, as both captive breeding and landscape intervention of wild populations increasingly require an explicit delineation of the conservation management units [7]. The recent coalescence to a late Pleistocene bottleneck (circa 110 kya) [5, 8, 9] poses challenges for detecting tiger subspecific morphological traits, suggesting that elucidating intraspecific evolution in the tiger requires analyses at the genomic scale. Here, we present whole-genome sequencing analyses from 32 voucher specimens that resolve six statistically robust monophyletic clades corresponding to extant subspecies, including the recently recognized Malayan tiger (P. tigris jacksoni). The intersubspecies gene flow is very low, corroborating the recognized phylogeographic units. We identified multiple genomic regions that are candidates for identifying the adaptive divergence of subspecies. The body-size-related gene ADH7 appears to have been strongly selected in the Sumatran tiger, perhaps in association with adaptation to the tropical Sunda Islands. The identified genomic signatures provide a solid basis for recognizing appropriate conservation management units in the tiger and can benefit global conservation strategic planning for this charismatic megafauna icon.
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http://dx.doi.org/10.1016/j.cub.2018.09.019DOI Listing
December 2018

Commentary: Campylobacter and Hemolytic Uremic Syndrome.

Foodborne Pathog Dis 2019 02 10;16(2):90-93. Epub 2018 Oct 10.

Eastern Regional Research Center , Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, Pennsylvania.

There are reports in the literature stating that Campylobacter infections can cause hemolytic uremic syndrome (HUS); however, a mechanism for how Campylobacter induces HUS has not been proposed by investigators. The most common bacterial inducer of HUS is the Shiga toxin-producing Escherichia coli (STEC), and a few cases of HUS are induced by an invasive Shigella dysenteriae or Streptococcus pneumoniae infection. Campylobacter spp. have not been shown to produce Shiga toxin (Stx) nor do they possess genetic elements capable of producing a Stx-like toxin. The neuraminidase associated with pneumococcal HUS has not been observed in Campylobacter. Therefore, in the absence of a well-defined toxic mechanism, it not clear that Campylobacter actually causes HUS.
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http://dx.doi.org/10.1089/fpd.2018.2513DOI Listing
February 2019

Potentially inappropriate medication use among hypertensive older African-American adults.

BMC Geriatr 2018 10 5;18(1):238. Epub 2018 Oct 5.

Charles R. Drew University of Medicine and Science, 1731 East 120th Street, Los Angeles, CA, 90005, USA.

Background: Inappropriate use of medications, particularly among minority older adults with co-morbidity, remains a major public health concern. The American Geriatrics Society (AGS) reports that Potentially Inappropriate Medication (PIM) continues to be prescribed for older adults, despite evidence of poor outcomes. The main objective of this study was to examine the prevalence of PIM use among underserved non-institutionalized hypertensive older African-American adults. Furthermore, this study examines potential correlations between PIM use and the number and type of chronic conditions.

Methods: This cross-sectional study is comprised of a convenience sample of 193 hypertensive non-institutionalized African-American adults, aged 65 years and older recruited from several senior housing units located in underserved areas of South Los Angeles. The updated 2015 AGS Beers Criteria was used to identify participants using PIMs.

Results: Almost one out of two participants had inappropriate medication use. While the average number of PIMs taken was 0.87 drugs, the range was from one to seven medications. Almost 23% of PIMs were due to drugs with potential drug-drug interactions. The most common PIM was the use of proton pump inhibitors (PPI) and Central Nervous System (CNS) active agents. Nearly 56% of PIMs potentially increased the risk of falls and fall-associated bone fractures. The use of PIMs was significantly higher among participants who reported a higher number of chronic conditions. Nearly 70% of participants with PIM use reported suffering from chronic pain.

Conclusions: The major reason for high levels of polypharmacy, PIMs, and drug interactions is that patients suffer from multiple chronic conditions. But it may not be possible or necessary to treat all chronic conditions. Therefore, the goals of care should be explicitly reviewed with the patient in order to determine which of the many chronic conditions has the greatest impact on the life goals and/or functional priorities of the patient. Those drugs that have a limited impact on the patient's functional priorities and that may cause harmful drug-drug interactions can be reduced or eliminated, while the remaining medications can focus on the most important functional priorities of the patient.
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http://dx.doi.org/10.1186/s12877-018-0926-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6173851PMC
October 2018

Using Gas Phase Reactions of Hexamethylene Triperoxide Diamine (HMTD) to Improve Detection in Mass Spectrometry.

J Am Soc Mass Spectrom 2018 04 25;29(4):675-684. Epub 2018 Jan 25.

Department of Chemistry, University of Rhode Island, 140 Flagg Rd, Kingston, RI, 02881, USA.

Our efforts to lower the detection limits of hexamethylene triperoxide diamine (HMTD) have uncovered previously unreported gas-phase reactions of primary and secondary amines with one of the six methylene carbons. The reaction occurs primarily in the atmospheric pressure chemical ionization (APCI) source and is similar to the behavior of alcohols with HMTD [1]. However, unlike alcohols, the amine reaction conserves the hydrogen peroxide on the intact product. Furthermore, with or without amines, HMTD is oxidized to tetramethylene diperoxide diamine dialdehyde (TMDDD) in a temperature-dependent fashion in the APCI source. Synthesized TMDDD forms very strong adducts (not products) to ammonium and amine ions in the electrospray ionization (ESI) source. Attempts to improve HMTD detection by generating TMDDD in the APCI source with post-column addition of amines were not successful. Signal intensity of the solvent related HMTD product in methanol, [HMTD+MeOH-HO] (m/z 207.0975), was understandably related to the amount of methanol in the HMTD environment as it elutes into the source. With conditions optimized for this product, the detection of 100 pg on column was accomplished with a robust analysis of 300 pg (1.44 pmol) routinely performed on the Orbitrap mass spectrometers. Graphical Abstract ᅟ.
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http://dx.doi.org/10.1007/s13361-017-1879-5DOI Listing
April 2018

Reactions of Organic Peroxides with Alcohols in Atmospheric Pressure Chemical Ionization-the Pitfalls of Quantifying Triacetone Triperoxide (TATP).

J Am Soc Mass Spectrom 2018 02 7;29(2):393-404. Epub 2017 Nov 7.

Department of Chemistry, University of Rhode Island, 140 Flagg Rd., Kingston, RI, 02881, USA.

Over the last several decades, mass spectrometry has become one of the principle methods for compound identification and quantification. While for analytical purposes, fragments which are not fully characterized in terms of origin and intensity as a function of experimental conditions have been used, understanding the nature of those species is very important. Herein we discuss such issues relative to triacetone triperoxide (TATP) and its frequently observed fragment at m/z 89. This "fragment" has been identified as the gas-phase reaction product of TATP with one or two methanol molecules/ions. Additionally, the origin and conditions of other fragments at m/z 91, 75, and 74 associated with TATP will be addressed. Similar analytical issues associated with other multi-peroxide organic compounds [hexamethylene triperoxide diamine (HMTD), methyl ethyl ketone peroxides (MEKP)] will also be discussed. Solution storage conditions for TATP, HMTD, and tetramethylene diperoxide diamine dialdehyde have been determined. Graphical Abstract ᅟ.
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http://dx.doi.org/10.1007/s13361-017-1836-3DOI Listing
February 2018

Characterizing the Performance of Pipe Bombs.

J Forensic Sci 2018 Jan 24;63(1):86-101. Epub 2017 May 24.

David Schatzer, Washington, DC.

Pipe bombs of steel or PVC fragment in reproducible patterns when similarly configured. The power of the explosion correlates with number, mass, and size of the fragments recovered, where a large number of small, low-mass fragments indicate a high-power event and vice versa. In discussing performance, describing pipe fragmentation pattern by fragment weight distribution mapping (FWDM) or fragment surface area distribution mapping (FSADM) was useful. When fillers detonated, detonation velocities of ~4.4 mm/μs were measured. In such cases, side walls of the pipe were thrown first; the average fragment velocity was ~1000 km/s. In deflagrations, the end cap was first thrown; fragment velocities were only ~240 km/s. Blast overpressures varied; at 10 feet, 2 × 12 inch steel pipes containing ~550 g of detonable mixture produced overpressures of 5-6 psi; similar nondetonating pipes produced less than 2 psi. Maximum fragment throw distances were 250-300 m, with an average of ~100 m.
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http://dx.doi.org/10.1111/1556-4029.13524DOI Listing
January 2018

Acetonitrile Ion Suppression in Atmospheric Pressure Ionization Mass Spectrometry.

J Am Soc Mass Spectrom 2016 11 30;27(11):1796-1804. Epub 2016 Aug 30.

Chemistry Department, University of Rhode Island, 51 Lower College Rd., Kingston, RI, 02881, USA.

Efforts to analyze trace levels of cyclic peroxides by liquid chromatography/mass spectrometry gave evidence that acetonitrile suppressed ion formation. Further investigations extended this discovery to ketones, linear peroxides, esters, and possibly many other types of compounds, including triazole and menadione. Direct ionization suppression caused by acetonitrile was observed for multiple adduct types in both electrospray ionization and atmospheric pressure chemical ionization. The addition of only 2% acetonitrile significantly decreased the sensitivity of analyte response. Efforts to identify the mechanism were made using various nitriles. The ion suppression was reduced by substitution of an acetonitrile hydrogen with an electron-withdrawing group, but was exacerbated by electron-donating or steric groups adjacent to the nitrile. Although current theory does not explain this phenomenon, we propose that polar interactions between the various functionalities and the nitrile may be forming neutral aggregates that manifest as ionization suppression. Graphical Abstract ᅟ.
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http://dx.doi.org/10.1007/s13361-016-1466-1DOI Listing
November 2016

Invasive evaluation of plaque morphology of symptomatic superficial femoral artery stenoses using combined near-infrared spectroscopy and intravascular ultrasound.

Vasc Med 2016 08 8;21(4):337-44. Epub 2016 Mar 8.

Department of Cardiovascular Medicine, Beaumont Health, Royal Oak, MI, USA

The purpose of this study is to characterize the plaque morphology of severe stenoses in the superficial femoral artery (SFA) employing combined near-infrared spectroscopy and intravascular ultrasound (NIRS-IVUS). Atherosclerosis is the most common cause of symptomatic peripheral arterial disease. Plaque composition of SFA stenoses has been characterized as primarily fibrous or fibrocalcific by non-invasive and autopsy studies. NIRS has been validated to detect lipid-core plaque (LCP) in the coronary circulation. We imaged severe SFA stenoses with NIRS-IVUS prior to revascularization in 31 patients (46 stenoses) with Rutherford claudication ⩾ class 3. Angiographic parameters included lesion location and stenosis severity. IVUS parameters included plaque burden and presence of calcium. NIRS images were analyzed for LCP and maximum lipid-core burden index in a 4-mm length of artery (maxLCBI4mm). By angiography, 38 (82.6%) lesions were calcified and 9 (19.6%) were chronic total occlusions. Baseline stenosis severity and lesion length were 86.0 ± 11.0% and 36.5 ± 46.5 mm, respectively. NIRS-IVUS identified calcium in 45 (97.8%) lesions and LCP in 17 (37.0%) lesions. MaxLCBI4mm was 433 ± 244. All lesions with LCP also contained calcium; there were no non-calcified lesions with LCP. In conclusion, this is the first study of combined NIRS-IVUS in patients with PAD. NIRS-IVUS demonstrates that nearly all patients with symptomatic severe SFA disease have fibrocalcific plaque, and one-third of such lesions contain LCP. These findings contrast with those in patients with acute coronary syndromes, and may have implications regarding the pathophysiology of atherosclerosis in different vascular beds.
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http://dx.doi.org/10.1177/1358863X16631420DOI Listing
August 2016

β-Blocker premedication does not increase the frequency of allergic reactions from coronary CT angiography: Results from the Advanced Cardiovascular Imaging Consortium.

J Cardiovasc Comput Tomogr 2015 Jul-Aug;9(4):270-7. Epub 2015 Feb 18.

Department of Cardiovascular Medicine, Beaumont Health System, 3601 W 13 Mile Road, Royal Oak, MI 48073, USA; Oakland University William Beaumont School of Medicine, Rochester, MI, USA. Electronic address:

Background: β-Blockers are often used for heart rate control during coronary CT angiography (CTA). Increased frequency and severity of allergic reactions to radiocontrast media (RCM) have been reported with concomitant use of β-blockers.

Objectives: The objectives of this study were to determine whether there is a higher incidence of allergic reactions to low-osmolar nonionic RCM in patients undergoing coronary CTA with concomitant β-blockers and to define the overall incidence and severity of allergic reactions in patients undergoing coronary CTA with and without a history of allergy to RCM.

Methods: Patients undergoing coronary CTA at 47 institutions participating in the Advanced Cardiovascular Imaging Consortium registry were analyzed. The incidence and severity of allergic reactions were compared between those patients who did and those who did not receive β-blockers, as well as in subgroups of patients with and without a history of prior allergy to RCM.

Results: The incidence of allergic reaction in patients who received β-blockers was 45 of 23,867 (0.19%) compared with those who did not receive β-blockers, which was 9 of 5232 (0.17%; P = .84; odds ratio = 1.1). Of the patients with history of allergy to RCM, 4 of 706 patients (0.6%) on β-blockers experienced allergic reactions compared to 1 of 77 patients (1.3%) without β-blockers (P = .40; odds ratio = 0.43).

Conclusions: β-Blocker pretreatment had no effect on the frequency or severity of allergic reaction in patients undergoing coronary CTA, even in patients with a past history of allergy to RCM.
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http://dx.doi.org/10.1016/j.jcct.2015.02.003DOI Listing
March 2016

Gas-phase reactions of alcohols with hexamethylene triperoxide diamine (HMTD) under atmospheric pressure chemical ionization conditions.

Rapid Commun Mass Spectrom 2015 Jan;29(1):74-80

Chemistry Department, University of Rhode Island, 51 Lower College Road, Kingston, RI 02881, USA.

Rationale: Hexamethylene triperoxide diamine (HMTD) is a sensitive peroxide explosive first synthesized in 1885. HMTD exhibits an unusual gas-phase phenomenon in the presence of alcohols that has been previously observed, but incorrectly resolved. We are attempting to determine this specific mechanism.

Methods: We used positive ion mode atmospheric pressure chemical ionization (APCI) as the interface to the mass spectrometer. HMTD was infused with various solvents including (18) O- and (2) H-labeled methanol in order to determine gas-phase reaction mechanisms.

Results: Based on these labeled experiments, it was determined that, under APCI conditions, the alcohol oxygen attacks a methylene carbon of HMTD and releases H2 O2 . This was attempted with nine different alcohols and, in each case, the alcohol is fully incorporated into the molecule with the peroxide release. A mechanism for this reaction has been proposed.

Conclusions: This work appears to have confirmed the gas-phase reaction mechanism of HMTD with alcohols. As we continue efforts to characterize this unusual molecule, the information may prove useful in determining formation and degradation mechanism(s). In addition, this property of HMTD may find use in other fields of science.
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http://dx.doi.org/10.1002/rcm.7084DOI Listing
January 2015

How much gene flow is needed to avoid inbreeding depression in wild tiger populations?

Proc Biol Sci 2014 Aug;281(1789):20133337

Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota, St Paul, MN 55108, USA.

The number and size of tiger populations continue to decline owing to habitat loss, habitat fragmentation and poaching of tigers and their prey. As a result, tiger populations have become small and highly structured. Current populations have been isolated since the early 1970s or for approximately seven generations. The objective of this study is to explore how inbreeding may be affecting the persistence of remaining tiger populations and how dispersal, either natural or artificial, may reduce the potentially detrimental effect of inbreeding depression. We developed a tiger simulation model and used published levels of genetic load in mammals to simulate inbreeding depression. Following a 50 year period of population isolation, we introduced one to four dispersing male tigers per generation to explore how gene flow from nearby populations may reduce the negative impact of inbreeding depression. For the smallest populations, even four dispersing male tigers per generation did not increase population viability, and the likelihood of extinction is more than 90% within 30 years. Unless habitat connectivity is restored or animals are artificially introduced in the next 70 years, medium size wild populations are also likely to go extinct, with only four to five of the largest wild tiger populations likely to remain extant in this same period without intervention. To reduce the risk of local extinction, habitat connectivity must be pursued concurrently with efforts to increase population size (e.g. enhance habitat quality, increase habitat availability). It is critical that infrastructure development, dam construction and other similar projects are planned appropriately so that they do not erode the extent or quality of habitat for these populations so that they can truly serve as future source populations.
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http://dx.doi.org/10.1098/rspb.2013.3337DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4100497PMC
August 2014

Sympatric Asian felid phylogeography reveals a major Indochinese-Sundaic divergence.

Mol Ecol 2014 Apr;23(8):2072-92

Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing, 100871, China.

The dynamic geological and climatological history of Southeast Asia has spawned a complex array of ecosystems and 12 of the 37 known cat species, making it the most felid-rich region in the world. To examine the evolutionary histories of these poorly studied fauna, we compared phylogeography of six species (leopard cat Prionailurus bengalensis, fishing cat P. viverrinus, Asiatic golden cat Pardofelis temminckii, marbled cat P. marmorata, tiger Panthera tigris and leopard P. pardus) by sequencing over 5 kb of DNA each from 445 specimens at multiple loci of mtDNA, Y and X chromosomes. All species except the leopard displayed significant phylogenetic partitions between Indochina and Sundaland, with the central Thai-Malay Peninsula serving as the biogeographic boundary. Concordant mtDNA and nuclear DNA genealogies revealed deep Indochinese-Sundaic divergences around 2 MYA in both P. bengalensis and P. marmorata comparable to previously described interspecific distances within Felidae. The divergence coincided with serial sea level rises during the late Pliocene and early Pleistocene, and was probably reinforced by repeated isolation events associated with environmental changes throughout the Pleistocene. Indochinese-Sundaic differentiations within P. tigris and P. temminckii were more recent at 72-108 and 250-1570 kya, respectively. Overall, these results illuminate unexpected, deep vicariance events in Southeast Asian felids and provide compelling evidence of species-level distinction between the Indochinese and Sundaic populations in the leopard cat and marbled cat. Broader sampling and further molecular and morphometric analyses of these species will be instrumental in defining conservation units and effectively preserving Southeast Asian biodiversity.
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http://dx.doi.org/10.1111/mec.12716DOI Listing
April 2014

Shiga toxin-producing Escherichia coli.

Adv Appl Microbiol 2014 ;86:145-97

USDA, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania, USA.

In the United States, it is estimated that non-O157 Shiga toxin-producing Escherichia coli (STEC) cause more illnesses than STEC O157:H7, and the majority of cases of non-O157 STEC infections are due to serogroups O26, O45, O103, O111, O121, and O145, referred to as the top six non-O157 STEC. The diseases caused by non-O157 STEC are generally milder than those induced by O157 STEC; nonetheless, non-O157 STEC strains have also been associated with serious illnesses such as hemorrhagic colitis and hemolytic uremic syndrome, as well as death. Ruminants, particularly cattle, are reservoirs for both O157 and non-O157 STEC, which are transmitted to humans by person-to-person or animal contact and by ingestion of food or water contaminated with animal feces. Improved strategies to control STEC colonization and shedding in cattle and contamination of meat and produce are needed. In general, non-O157 STEC respond to stresses such as acid, heat, and other stresses induced during food preparation similar to O157 STEC. Similar to O157:H7, the top six non-O157 STEC are classified as adulterants in beef by the USDA Food Safety and Inspection Service, and regulatory testing for these pathogens began in June 2012. Due to the genetic and phenotypic variability of non-O157 STEC strains, the development of accurate and reliable methods for detection and isolation of these pathogens has been challenging. Since the non-O157 STEC are responsible for a large portion of STEC-related illnesses, more extensive studies on their physiology, genetics, pathogenicity, and evolution are needed in order to develop more effective control strategies.
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http://dx.doi.org/10.1016/B978-0-12-800262-9.00003-2DOI Listing
May 2014

Effect of cardiorespiratory fitness on short-term morbidity and mortality after coronary artery bypass grafting.

Am J Cardiol 2013 Oct 10;112(8):1104-9. Epub 2013 Jul 10.

Department of Cardiovascular Medicine, William Beaumont Hospital, Beaumont Health System, Royal Oak, Michigan.

Although preoperative risk assessment for coronary artery bypass grafting (CABG) has been evaluated with multiple predictive models, none have incorporated a low level of cardiorespiratory fitness, which represents one of the strongest predictors of all-cause and cardiovascular mortality in subjects with and without heart disease. The aim of the present study was to evaluate preoperative cardiorespiratory fitness, expressed as METs (1 MET = 3.5 ml O2/kg/min), and short-term morbidity and mortality after CABG. The Society of Thoracic Surgeons database was queried for patients who underwent CABG from January 2002 to December 2010 at Beaumont Health Systems. Electronic medical records were reviewed for peak or symptom-limited exercise testing <90 days before CABG. Peak METs were estimated from the achieved treadmill speed, grade, and duration or the cycle ergometer workload, corrected for body weight. Patients who met eligibility criteria (n = 596) were categorized into 2 groups: those with reduced aerobic capacity (<5 METs [n = 78]) and those achieving ≥5 METs (n = 518). Fisher's exact tests were used to compare preoperative aerobic capacity and short-term postoperative morbidity and mortality between the 2 groups. After adjusting for potential confounding variables, an inverse relation was found between cardiorespiratory fitness and complications after CABG. Specifically, low preoperative cardiorespiratory fitness (<5 METs) was associated with higher operative and 30-day mortality after CABG (p <0.05). In conclusion, these data suggest that preoperative cardiorespiratory fitness provides an independent and additive marker for mortality after CABG.
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http://dx.doi.org/10.1016/j.amjcard.2013.05.057DOI Listing
October 2013

How does Listeria monocytogenes combat acid conditions?

Can J Microbiol 2013 Mar 20;59(3):141-52. Epub 2012 Dec 20.

Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038-8598, USA.

Listeria monocytogenes, a major foodborne pathogen, possesses a number of mechanisms that enable it to combat the challenges posed by acidic environments, such as that of acidic foods and the gastrointestinal tract. One mechanism employed by L. monocytogenes for survival at low pH is the adaptive acid tolerance response (ATR) in which a short adaptive period at a nonlethal pH induces metabolic changes that allow the organism to survive a lethal pH. Overcoming acid conditions by L. monocytogenes involves a variety of regulatory responses, including the LisRK 2-component regulatory system, the SOS response, components of the σ(B) regulon, changes in membrane fluidity, the F0F1-ATPase proton pump, and at least 2 enzymatic systems that regulate internal hydrogen ion concentration (glutamate decarboxylase and arginine deiminase). It is not clear if these mechanisms exert their protective effects separately or in concert, but it is probable that these mechanisms overlap. Studies using mutants indicate that the glutamate decarboxylase system can protect L. monocytogenes when the organism is present in acidic juices, yogurt, salad dressing, mayonnaise, and modified CO2 atmospheres. The glutamate decarboxylase system also has a role in protecting L. monocytogenes against the acidic environment of the stomach. There is a need to study other acid resistance mechanisms of L. monocytogenes to determine their effectiveness in protecting the organism in acidic foods or during transit through the acid stomach.
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http://dx.doi.org/10.1139/cjm-2012-0392DOI Listing
March 2013

Effect of stress on non-O157 Shiga toxin-producing Escherichia coli.

J Food Prot 2012 Dec;75(12):2241-50

U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA.

Non-O157 Shiga toxin-producing Escherichia coli (non-O157 STEC) strains have emerged as important foodborne pathogens worldwide. Non-O157 STEC serogroups O26, O45, O103, O111, O121, and O145 have been declared as adulterants in beef by the U. S. Department of Agriculture Food Safety and Inspection Service. While documentation is limited, treatments including heat and acid that have been shown to inactivate E. coli O157:H7 will likely also destroy non-O157 STEC; however, non-O157 STEC strains show variability in their responses to stress. It has been shown that non-O157 STEC may survive in fermented sausages and cheeses, and treatments such as high pressure may be necessary to eliminate non-O157 STEC from these products. The mechanisms used by non-O157 STEC to resist acid environments are similar to those used by O157:H7 strains and include the acid tolerance response, the oxidative system, and the glutamate and arginine decarboxylase systems. However, one study demonstrated that some non-O157 STEC strains utilize a chaperone-based acid stress response (HdeA and HdeB) to combat acidic conditions, which is lacking in E. coli O157:H7. Genomic studies suggest that while non-O157 STEC can cause diseases similar to those caused by E. coli O157:H7, O157 and non-O157 STECs have different evolutionary histories. Non-O157 STECs are a heterogeneous group of organisms, and there is currently a limited amount of information on their virulence, fitness, and stress responses, rendering it difficult to draw firm conclusions on their behavior when exposed to stress in the environment, in food, and during processing.
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http://dx.doi.org/10.4315/0362-028X.JFP-12-255DOI Listing
December 2012

Composition of target lesions by near-infrared spectroscopy in patients with acute coronary syndrome versus stable angina.

Circ Cardiovasc Interv 2012 Feb 17;5(1):55-61. Epub 2012 Jan 17.

Frederik Meijer Heart and Vascular Institute, Spectrum Health System, Grand Rapids, MI, USA.

Background: Whereas acute coronary syndromes (ACS) typically develop from the rupture of lipid core plaque (LCP), lesions causing stable angina are believed to be composed of fibrocalcific plaque. In this study, intracoronary near-infrared spectroscopy (NIRS) was used to determine the frequency of LCP at target and remote sites in patients with ACS versus those with stable angina.

Methods And Results: The study was performed in patients having ≥1 target lesion identified by invasive angiography who also underwent NIRS before intervention. LCP was defined as a 2-mm segment on the NIRS block chemogram having a strong positive reading indicated by a bright-yellow color. Patients with ACS and those with stable angina were compared for the frequency of LCP at target and remote sites. Among 60 patients (46.7% with ACS) undergoing invasive angiography and NIRS, 68 target lesions were identified. Although target lesions in patients with ACS were more frequently composed of LCP than targets in patients with stable angina (84.4% versus 52.8%, P=0.004), approximately one half of target lesions in patients with stable angina contained LCP. LCPs anatomically remote from the target lesion were frequent in patients with ACS and less common in patients with stable angina (73.3% versus 17.6%, P=0.002).

Conclusions: Target lesions responsible for ACS were frequently composed of LCP; in addition, LCPs often were found in remote, nontarget areas. Both target and remote LCPs were more common in patients with ACS than in those with stable angina. Approximately one half of target lesions in stable patients were also composed of LCP.
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http://dx.doi.org/10.1161/CIRCINTERVENTIONS.111.963934DOI Listing
February 2012

Accumulation of explosives in hair--Part 3: Binding site study.

J Forensic Sci 2012 May 11;57(3):623-35. Epub 2012 Jan 11.

Department of Chemistry, University of Rhode Island, Kingston, RI 02881, USA.

This study extends previous work on the sorption of explosives to the hair matrix. Specifically, we have studied the interaction of 2,4,6-trinitrotoluene (TNT) and triacetone triperoxide (TATP) as a function of chemical pretreatment with acetonitrile, neutral and alkaline hydrogen peroxide, methanolic KOH and potassium permanganate, and the morphological changes that accompany these treatments. While differences in vapor pressure can account for quantitative differences between TNT and TATP sorption, both are markedly affected by the chemical rinses. Examination of the hair surface shows different degrees of smoothening following rinsing, suggesting that the attachment to hair is largely a surface phenomenon involving the 18-methyleicosanoic acid lipid layer. Density functional theory calculations were employed to explore possible nucleation sites of TATP microcrystals on the hair. We conclude that some of the sites on melanin granular surfaces may support nucleation of TATP microcrystals. Moreover, the calculations support the experimental finding that dark hair adsorbs explosives better than light hair.
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http://dx.doi.org/10.1111/j.1556-4029.2011.02020.xDOI Listing
May 2012

Role of metal ions in the destruction of TATP: theoretical considerations.

J Phys Chem A 2011 Sep 1;115(38):10565-75. Epub 2011 Sep 1.

Institute of Chemistry, Hebrew University, Jerusalem, Israel.

The safe decomposition of solid TATP (triacetone triperoxide) explosive is examined theoretically. The route to destruction starts with formation of metal complexes between a metal ion and the TATP molecule. The second step is decomposition of the molecules into stable final products. We examined the structure and stability of both metal ion (including Na(+), Cu(+), Cu(2+), Co(2+), and Zn(2+)) and proton complexes with TATP using quantum chemical calculations at the DFT-PBE0 level of theory. In addition, for each ion complex, we determined the initial steps in the pathway to decomposition together with the associated transition states. We find that the products of decomposition, in particular, acetone, are also stabilized by ion metal complexes. In agreement with experiment, we find the best candidates for metal ion induced decomposition are Cu(2+) and Zn(2+).
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http://dx.doi.org/10.1021/jp2021616DOI Listing
September 2011

Virulence Plasmid (pYV)-Associated Expression of Phenotypic Virulent Determinants in Pathogenic Yersinia Species: A Convenient Method for Monitoring the Presence of pYV under Culture Conditions and Its Application for Isolation/Detection of Yersinia pestis in Food.

J Pathog 2011 14;2011:727313. Epub 2011 Sep 14.

Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA.

In Yersinia pestis, Y. pseudotuberculosis, and Y. enterocolitica, phenotypic expression of virulence plasmid (pYV: 70-kb)-associated genetic determinants may include low-calcium response (Lcr, pinpoint colony, size = 0.36 mm), colony morphology (size = 1.13 mm), crystal violet (CV) binding (dark-violet colony), Congo Red (CR) uptake (red pinpoint colony, size = 0.36 mm), autoagglutination (AA = cells agglutinate), and hydrophobicity (HP = clumping of cells). Y. pseudotuberculosis is chromosomally closely related to Y. pestis; whereas, Y. enterocolitica is chromosomally more distantly related to Y. pestis and Y. pseudotuberculosis. All three species demonstrate Lcr, CV binding, and CR uptake. The colony morphology/size, AA, and HP characteristics are expressed in both Y. pseudotuberculosis and Y. enterocolitica but not in Y. pestis. Congo red uptake in Y. pestis was demonstrated only on calcium-deficient CR magnesium oxalate tryptic soy agar (CR-MOX), whereas this phenotype was expressed on both CR-MOX and low-calcium agarose media in Y. pseudotuberculosis and Y. enterocolitica. These phenotypes were detectable at 37°C within 24 h in Y. enterocolitica and Y. pseudotuberculosis but did not appear until 48 h in Y. pestis due to its slower growth rate at 37°C. The pYV is unstable (i.e., easily lost under a variety of culture conditions) in all three species but is more unstable in Y. pestis. The specific CR uptake by Y. pestis in CR-MOX and the delayed time interval to express Lcr and CR uptake provide a means to differentiate Y. pestis from Y. enterocolitica and Y. pseudotuberculosis. These differences in pYV expression in Y. pestis can be used for its isolation and detection in food.
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http://dx.doi.org/10.4061/2011/727313DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3335626PMC
August 2012

Eavesdropping by bacteria: the role of SdiA in Escherichia coli and Salmonella enterica serovar Typhimurium quorum sensing.

Foodborne Pathog Dis 2011 Feb 30;8(2):169-78. Epub 2010 Oct 30.

Microbial Food Safety Research Unit, Agricultural Research Service, United States Department of Agriculture, Eastern Regional Research Center, Wyndmoor, PA 19038, USA.

Many gram-negative bacteria utilize N-acyl-L-homoserine lactones (AHLs) to bind to transcriptional regulators leading to activation or repression of target genes. Escherichia coli and Salmonella enterica do not synthesize AHLs but do contain the AHL receptor, SdiA. Studies reveal that SdiA can bind AHLs produced by other bacterial species and thereby allow E. coli and S. enterica to regulate gene transcription. The Salmonella sdiA gene regulates the rck gene, which mediates Salmonella adhesion and invasion of epithelial cells and the resistance of the organism to complement. In E. coli, there is some evidence that SdiA may regulate genes associated with acid resistance, virulence, motility, biofilm formation, and autoinducer-2 transport and processing. However, there is a lack of information concerning the role of SdiA in regulating growth and survival of E. coli and Salmonella in food environments, and therefore studies in this area are needed.
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http://dx.doi.org/10.1089/fpd.2010.0651DOI Listing
February 2011

A procedure for monitoring the presence of the virulence plasmid (pYV) in Yersinia pestis under culture conditions.

Foodborne Pathog Dis 2011 Mar 29;8(3):459-63. Epub 2010 Oct 29.

Molecular Characterization of Foodborne Pathogens Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania 19038, USA.

The pathogenicity of Yersinia pestis depends on the presence of a virulence plasmid (pYV). The unstable nature of pYV in Y. pestis leads to the eventual outgrowth of pYV-less cells due to its higher growth rate. Thus, it was necessary to develop procedures to monitor the presence of the plasmid during cultivation, storage, and laboratory manipulations. A procedure was developed to monitor the presence of pYV in Y. pestis by using low calcium response and Congo red binding techniques. The selection of pYV in the isolated clones was confirmed by polymerase chain reaction and by expression of pYV-associated phenotypes. Thus, using this procedure, low calcium response-Congo red-positive clones can be isolated for use in the development of growth models of virulent Y. pestis in food.
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http://dx.doi.org/10.1089/fpd.2010.0663DOI Listing
March 2011
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