Insects as Chemical Sensors: Detection of Chemical Warfare Agent Simulants and Hydrolysis Products in the Blow Fly Using LC-MS/MS

In this work, blow flies were investigated as environmental chemical sample collectors following a chemical warfare attack (CWA). Blow flies sample the environment as they search for water and food sources and can be trapped from kilometers away using baited traps. Three species of blow flies were exposed to CWA simulants to determine the persistence and detectability of these compounds under varying environmental conditions. A liquid chromatography mass spectrometry (LC-MS/MS) method was developed to detect CWA simulants and hydrolysis products from fly guts. Flies were exposed to the CWA simulants dimethyl methylphosphonate and diethyl phosphoramidate as well as the pesticide dichlorvos, followed by treatment-dependent temperature and humidity conditions. Flies were sacrificed at intervals within a 14 day postexposure period. Fly guts were extracted and analyzed with the LC-MS/MS method. The amount of CWA simulant in fly guts decreased with time following exposure but were detectable 14 days following exposure, giving a long window of detectability. In addition to the analysis of CWA simulants, isopropyl methylphosphonic acid, the hydrolysis product of sarin, was also detected in blow flies 14 days post exposure. This work demonstrates the potential to obtain valuable samples from remote or access-restricted areas without risking lives.

Simultaneous quantitation of five triazole anti-fungal agents by paper spray-mass spectrometry

Background Invasive fungal disease is a life-threatening condition that can be challenging to treat due to pathogen resistance, drug toxicity, and therapeutic failure secondary to suboptimal drug concentrations. Frequent therapeutic drug monitoring (TDM) is required for some anti-fungal agents to overcome these issues. Unfortunately, TDM at the institutional level is difficult, and samples are often sent to a commercial reference laboratory for analysis. To address this gap, the first paper spray-mass spectrometry assay for the simultaneous quantitation of five triazoles was developed. Methods Calibration curves for fluconazole, posaconazole, itraconazole, hydroxyitraconazole, and voriconazole were created utilizing plasma-based calibrants and four stable isotopic internal standards. No sample preparation was needed. Plasma samples were spotted on a paper substrate in pre-manufactured plastic cartridges, and the dried plasma spots were analyzed directly utilizing paper spray-mass spectrometry (paper spray MS/MS). All experiments were performed on a Thermo Scientific TSQ Vantage triple quadrupole mass spectrometer. Results The calibration curves for the five anti-fungal agents showed good linearity (R2 = 0.98-1.00). The measured assay ranges (lower limit of quantification [LLOQ]-upper limit of quantitation [ULOQ]) for fluconazole, posaconazole, itraconazole, hydroxyitraconazole, and voriconazole were 0.5-50 μg/mL, 0.1-10 μg/mL, 0.1-10 μg/mL, 0.1-10 μg/mL, and 0.1-10 μg/mL, respectively. The inter- and intra-day accuracy and precision were less than 25% over the respective ranges. Conclusions We developed the first rapid paper spray-MS/MS assay for simultaneous quantitation of five triazole anti-fungal agents in plasma. The method may be a powerful tool for near-point-of-care TDM aimed at improving patient care by reducing the turnaround time and for use in clinical research.

Female Blow Flies As Vertebrate Resource Indicators

Rapid vertebrate diversity evaluation is invaluable for monitoring changing ecosystems worldwide. Wild blow flies naturally recover DNA and chemical signatures from animal carcasses and feces. We demonstrate the power of blow flies as biodiversity monitors through sampling of flies in three environments with varying human influences: Indianapolis, IN and two national parks (the Great Smoky Mountains and Yellowstone). Dissected fly guts underwent vertebrate DNA sequencing (12S and 16S rRNA genes) and fecal metabolite screening. Integrated Nested Laplace Approximation (INLA) was used to determine the most important abiotic factor influencing fly-derived vertebrate richness. In 720 min total sampling time, 28 vertebrate species were identified, with 42% of flies containing vertebrate resources: 23% DNA, 5% feces, and 14% contained both. The species of blow fly used was not important for vertebrate DNA recovery, however the use of female flies versus male flies directly influenced DNA detection. Temperature was statistically relevant across environments in maximizing vertebrate detection (mean = 0.098, sd = 0.048). This method will empower ecologists to test vertebrate community ecology theories previously out of reach due practical challenges associated with traditional sampling.

Use of competing conceptions of risk in animal agriculture

This study considers a theory of risk as a means of coping with risk and uncertainty that have become a growing reality for animal agriculture. Microbial contaminations of food, waste management, animal products in the human diet, and transmissible spongiform encephalopathies (TSE) incorporate different conceptions of risk and require different approaches to handling the uncertainty involved. A dichotomous schema is suggested to assist understanding risk that may be adapted to recognizing and handling risk. The polar aspects of the proposal are the probabilistic approach at one end and the contextual understanding at the other. Probabilist conceptions of risk presume that risk is determined by probability and consequence. Contextual conceptions presume that management, law, regulation, media, and public perceptions, as well as the severity of the consequence, will figure prominently in decision making in the face of uncertainty. Relative emphasis on probabilistic characteristics shapes distinct understandings of risk that can be plotted between the poles. We are proposing that these conceptualizations need not be issues only for debate but also for recognition of the probabilistic or contextual nature of the risk. Specific actions and policy may be constructed on the basis of the conceptualization. The bovine spongiform encephalopathy/new variant Creutzfeldt-Jakob disease complex is examined philosophically and methodologically as a contextual challenge to animal agriculture and associated industries. As such, the TSE serve as a case study of effective application of risk theory to risks in animal agriculture.

Effects of subject velocity on ground reaction force measurements and stance times in clinically normal horses at the walk and trot

OBJECTIVE

The objective of the study reported here was to evaluate the effects of changing velocity on stance time and ground reaction force (GRF) measurements in horses at the walk and trot.

DESIGN

Force plate gait analysis was used to evaluate clinically normal horses at variable velocities. Ground reaction force measurements and stance times were recorded and compared.

ANIMALS

12 adult horses.

PROCEDURE

Data were obtained from 192 valid trials at the walk and 162 valid trials at the trot. Vertical, braking, and propulsive peak forces and impulses were measured. Pearson's correlation coefficients were determined for velocity and stance time and all measured forces and impulses in the forelimbs and hind limbs. Trials were divided into distinct velocity ranges. Trials obtained at velocities within the established ranges were analyzed to evaluate changes in vertical, braking, and propulsive peak forces and impulses at differing speeds within the walk and trot gaits.

RESULTS

At the walk and trot, a significant negative correlation was found between velocity and forelimb and hind limb stance times. Velocity and stance time were significantly correlated with many of the GRF and impulse measurements. Velocity was significantly correlated with vertical and braking forces in the hind limbs at the walk, with vertical force in the forelimbs at the trot, and with braking force in the forelimbs and hind limbs at the trot. Velocity and stance time correlated significantly with forelimb and hind limb vertical impulses. Forelimb and hind limb stance times decreased significantly as velocity increased. Hind limb braking force increased and forelimb and hind limb vertical impulses decreased significantly as walk velocity increased. Forelimb braking force increased significantly between velocity ranges at the trot.

CONCLUSIONS

Results of this study confirm that a significant negative linear correlation exists between subject velocity and stance times in clinically normal horses at the walk and trot. Significant correlations were also identified between velocity and many GRF measurements, indicating that subject velocity does influence the generation of GRF measurements in horses. Variation in subject velocity should be minimized when performing force-plate analysis in horses.

Sensory, physical, and chemical properties of pork loin chops from somatotropin-treated pigs of three stress classifications

Forty-eight pigs of three known stress classifications were injected daily with porcine somatotropin (pST; 4 mg/d) or placebo. The effects of pST and stress classification on the sensory, physical and chemical characteristics of loin chops were observed. Chops from pST-treated animals were less tender and juicy than chops from control animals. Positive stress classification also significantly decreased juiciness but had no effect on tenderness and flavor. A significant interaction was observed for initial juiciness and sustained juiciness between chops from pST and stress-positive pigs. Whereas chops from carriers and normal pigs showed a reduction in juiciness traits with the pST treatment, among stress-positive animals both initial and sustained juiciness were increased with pST treatment. Treatment with pST had no effect on the fat, protein, and moisture content of the longissimus muscle. Furthermore, stress classification had no effect on the fat and moisture content of the longissimus muscle, but protein content was significantly higher in loin chops from stress-positive animals. Chops from pST-treated animals had significantly higher maximum shear force values, required more energy to break the sample, and had higher yield point values than chops from control animals, but stress classification did not affect the shear force values significantly. Treatment of stress-susceptible animals with pST does not lead to an increased incidence of pale, soft, exudative meat and may improve juiciness attributes of chops from stress-positive animals. However, pST treatment of animals, in this trial, led to a reduction of juiciness and tenderness of pork loin chops.

Sensory and processing properties of cured semimembranosus muscle from stress-susceptible pigs treated with porcine somatotropin

Forty-eight Yorkshire cross pigs of three stress susceptibility classes (stress positive, stress-carrier, and stress negative) were injected daily with porcine somatotropin (pST; 4 mg/d) or placebo. Each pig was injected in the neck once daily until taken off test, starting when the pigs weighed 59 kg. Porcine somatotropin treatment was terminated at weekly intervals as individual pigs reached 109 kg, but animals continued to be fed for six additional days to allow for required withdrawal time. The effect of pST and stress classification on the sensory, physical, chemical, and processing characteristics of cured semimembranosus (SM) muscle was evaluated. Treatment of animals with pST had no effect on the sensory scores, lipid and protein content, cooking yields, or color values of SM muscle slices. Semimembranosus muscles from stress-positive animals, however, had reduced sensory scores for texture, flavor, and overall palatability. Semimembranosus muscles from stress-positive pigs also had smaller cooking yields and greater Hunter a and b values of processed slices. The greater Hunter a and b values suggested that the color of these slices were redder and yellower than the color of SM muscle slices from negative and carrier animals. Semimembranosus muscles from stress-susceptible animals also had a significantly lower lipid content. Treatment of animals with pST did not significantly alter sensory, chemical, or processing characteristics of SM muscle slices from these animals.

Effect of porcine somatotropin, stress susceptibility, and final end point of cooking on the sensory, physical, and chemical properties of pork loin chops

Forty-eight pigs of three known stress susceptibility classes were injected daily with porcine somatotropin (pST; 4 mg/d) or a placebo. Each pig was injected in the neck once daily until taken off test, starting when the pigs weighed 59 kg. The pST treatment was terminated at weekly intervals when individual pigs reached 109 kg, but animals continued to be fed for six additional days to allow for required withdrawal time. The effect of pST and stress classification on the sensory, physical, and chemical characteristics of pork chops was observed. Also, the effect of two end-point temperatures (71 and 77 degrees C) on the sensory attributes was observed. The pST treatment of animals resulted in a small but significant decrease in panel scores for tenderness, juiciness, and flavor. Stress susceptibility class, however, decreased panel scores for tenderness only. The pST treatment reduced intramuscular fat and increased moisture in the longissimus muscle, but stress susceptibility class had no effect on proximate composition. The pST treatment and stress susceptibility decreased and increased Hunter L values of chops, respectively, indicating darker and lighter colors, respectively. Furthermore, a greater end-point temperature reduced sensory scores for tenderness and juiciness. These results suggest that pST treatment does not cause an increased incidence of pale, soft, exudative muscle. Also, the use of a lower temperature of end-point doneness (71 degrees C) should be implemented to optimize palatability of broiled pork chops regardless of pST treatment.

Pulsatile or continuous infusion of luteinizing hormone-releasing hormone and hormonal concentrations in prepubertal beef heifers

An experiment was conducted to determine if exogenous luteinizing hormone-releasing hormone (LHRH) administered iv intermittently as pulses (P) or by continuous sc infusion (I) using osmotic minipumps could sustain pulsatile LH release and induce estrous cyclicity in prepubertal heifers. Prepubertal heifers were assigned randomly to: 1) receive pulses of LHRH (n = 6; 2.5 micrograms LHRH/2 h for 72 h), 2) be infused with LHRH (n = 11; 1.25 micrograms LHRH/h for 72 h), or 3) serve as controls (n = 16). Blood was collected at 20-min intervals for 8 h (0900 to 1700 h) from six heifers in each group on d 1, 2, 3 (during treatment), and on d 4 (during 8 h after terminating LHRH treatments). Heifers given LHRH had higher (P less than .01) LH concentrations than controls. Preovulatory-like LH surges occurred in three I, two P and no control heifers during treatment. Pulse frequencies of LH (no. LH pulses/8 h) were greater (P less than .001) for P heifers than for I and control heifers due to pulsatile LHRH treatment. Serum estradiol was higher (P less than .01) during treatment for LHRH-treated heifers than for controls. Serum follicle-stimulating hormone, cortisol, and progesterone were unchanged during treatment. High levels of cortisol on d 1 declined (P less than .001) to baseline by d 2. Characteristic progesterone rises or short luteal phases occurred within 10 d of treatment initiation in more (P less than .05) LHRH-treated heifers (I = 45%, P = 33%) than controls (6%), although days to first observed estrus and first ovulation were unaffected by treatments. Although both continuous and pulsatile administration of LHRH successfully induced LH and estradiol release as well as preovulatory-like LH surges in some heifers, earlier initiation of estrous cycles was not achieved. Estrous cycles appeared to be delayed by exposure to continuous LHRH infusions during the peripubertal period.