Sorption and Enantiomerization of Current Use Chiral Pesticides

Chiral pesticides are prevalent in the environment today and are known to react selectively with chiral environmental components such as microbes, enzymes, and other naturally occurring chiral materials. In addition, chiral sorption is a process that has been occasionally investigated in the study of homochirality (the exclusive presence of one enantiomer in living organisms), but almost overlooked in environmental science. For chiral sorption to occur, the sorbent and sorbate must be chiral entities. In the environment, there are abundant natural surfaces that are chiral, including clay minerals and organic matter present in soil, sediment and aqueous solution. A knowledge of isomerization, including the special case of enantiomerization, of chiral pesticides is also crucial in understanding the fate of these chiral pollutants, especially for pesticides marketed as a \u27chiral switch\u27:, i.e. formulations containing only or mostly the active enantiomer. The goal of this research was to provide more insight into sorption and enantiomerization of chiral pesticides in the presence of mineral surfaces. Sorption experiments with malathion and metalaxyl and selected minerals, along with their individual enantiomers, were conducted and results analyzed by achiral and chiral high performance liquid chromatography (HPLC). Investigation with racemic malathion resulted in significant sorption to all sorbents, with the exception of the negligible sorption to kaolinite. Sorption was fit to the Freundlich model, with n2hr \u3e 1 for bentonite, calcite, and montmorillonite while the biotic solids diatomaceous earth and seashells had n2hr \u3c 1. KF,2hr values indicated decreasing sorption capacity in the order montmorillonite, bentonite, calcite, seashells, and diatomaceous earth. Chiral analysis indicated nonenantioselective sorption for malathion, which exhibited racemic enantiomeric fractions (EFs) for all sorbents. Sorption of the individual enantiomers of malathion, R-(+)- and S-(-)-malathion, resulted in enantiomerization to racemic EFs after contact with the mineral sorbents. Adding malathion enantiomers to minerals and analyzing the aqueous phase after 15 min of centrifugation resulted in enantiomerization to racemic EF values for R-(+)-malathion, but only partial enantiomerization of S-(-)-malathion. Malathion enantiomers also decreased or increased in EF for controls containing either only water or â-cyclodextrin, but enantiomerization to the racemate was not complete after two hours. It was hypothesized that malathion is undergoing proton exchange with the mineral surfaces causing enantiomerization. Construction of sorption isotherms revealed that the racemate and enantiomers have different isotherm shapes, possibly indicating different sorption mechanisms. Sorption was fit to the Freundlich model, with n2hr being statistically different for the racemate and S-(-)-malathion and R-(+)- and S-(-)-malathion with bentonite, but not for calcite and montmorillonite. KF,2hr values were not significantly different for the racemate and enantiomers for bentonite, calcite, or montmorillonite, suggesting that the minerals had the same sorption capacity for the racemate or enantiomers. Racemic metalaxyl and metalaxyl-M (consisting of 97% R-(-)-metalaxyl and 3% S-(+)-metalaxyl) were found to sorb to bentonite and montmorillonite, but sorption to calcite and kaolinite was not apparent. Sorption was fit to the Freundlich model with n \u3e 1 and KF indicating that bentonite had a higher sorption capacity than montmorillonite. Sorption of R-(-)-metalaxyl from metalaxyl-M was greater than racemic metalaxyl for both sorbents, but S-(+)-metalaxyl sorption was the greatest overall after consideration of the small amount of S-(+)-metalaxyl present in metalaxyl-M. Chiral analysis indicated that sorption of racemic metalaxyl was nonenantioselective with racemic EFs. However, sorption of metalaxyl-M resulted in an increase of EF with bentonite and montmorillonite indicating the possibility of enantioselective sorption. Solution EFs also increased for calcite, and at one concentration level EF decreased for kaolinite, suggesting that enantiomerization is occurring for metalaxyl-M when in contact with these sorbents, since sorption on calcite and kaolinite was not observed. Although enantiomerization of chiral pesticides has been observed during degradation and in aprotic solvents, this research presents the first evidence of enantiomerization during sorption for two current-use chiral pesticides. The rapid enantiomerization of malathion and the enantiomerization and possible enantioselective sorption of metalaxyl to mineral surfaces questions the efficacy of using a chiral switch for these two pesticides. This research substantiates the need for enantiomer specific sorption analysis for chiral pesticides to understand their fate and effects in the environment

Searching for our foremothers: A philosophical journey through the alternative genres of women writers

In the history of philosophy, there is a shortage, and often a total absence, of women’s voices in the philosophical canon. I take this notable lack of female philosophical contribution not as evidence that women were not ‘capable’ or ‘interested’ in philosophical inquiry, but rather that their contributions are mainly to be found in alternative genres that were more open for women to participate in. I propose that present-day philosophers who are interested in locating the philosophical activities of women would benefit from an exploration of what I am terming “alternative genres.” I shall focus in particular on personal correspondence during the Early Modern period, the novel in the nineteenth century, and feminist cinema in the twentieth century. Each of these forms contributes a richly unique perspective on central philosophical themes and affords contemporary philosophers a venue through which to access the philosophical thought of women writers in these historical periods

The Impact of Resilience on a Middle Manager’s Resistance to Organizational Change

Change is never ending in organizations, as it is necessary to maintain a competitive advantage. Although change is needed, research shows most change implementations do not succeed. Middle managers (MMs) are considered the main facilitators of change. They receive directive for change and are tasked with not only processing and accepting the change but also communicating the directive down into the ranks and executing upon it. This basic qualitative study explored how resilience can aid an MM when implementing change, where resistance is present. The conceptual framework for this study included Lewin’s (1947) three-stage model of change theory and the resilience theory. The participants interviewed were 10 individuals who had experienced resistance as a middle manager because of a change directive. Each individual described their experiences and were asked prompts from a semistructured interview protocol document when specifics were not covered freely. Transcripts of these interviews were used for a basis of data that were coded to identify themes that impacted the MM’s resilience negatively or positively and created the discussion and recommendations for the findings. The overall finding of this research proved that positive leadership had the main effect on resilience during times of change resistance for MMs

Predators exacerbate competitive interactions and dominance hierarchies between two coral reef fishes

Predation and competition are critical processes influencing the ecology of organisms, and can play an integral role in shaping coral reef fish communities. This study compared the relative and interacting effects of competition and predation on two competing species of coral reef fish, Pomacentrus amboinensis and P. moluccensis (Pomacentridae), using a multifactorial experiment. Fish were subjected to the sight and smell of a known predator (Pseudochromis fuscus), the presence of the heterospecific competitor (i.e., P. amboinensis vs. P. moluccensis), or a combination of the two for a period of 19 days. The sub-lethal effects of predator/competitor treatments were compared with controls; a combination of otolith microstructure analysis and observations were used to determine otolith growth patterns and behaviour. We predicted that the stress of competition and/or predation would result in strong sub-lethal impacts, and act synergistically on growth and behavioural patterns. We found strong evidence to support this prediction, but only for P. amboinensis, which suffered reductions in growth in both predator and competitor treatments, with the largest reductions occurring when subjected to both predation and competition concurrently. There was strong evidence of asymmetrical competition between the two damselfish species, with P. moluccensis as the dominant competitor, displaying strong aggressive behaviour towards P. amboinensis. Growth reductions for P. amboinensis in predator/competitor treatments appeared to come about primarily due to increases in shelter seeking behaviour, which significantly reduced the foraging rates of individuals compared with controls. These data highlight the importance of predator/competitor synergisms in influencing key behaviours and demographic parameters for juvenile coral reef fishes

Patterns of Selection Amongst Dengue Virus Serotypes and Efficacy of Computational Epitope Prediction Applications

Dengue virus (DENV) is a mosquito-borne virus of global concern that leads to infections with symptoms ranging from high fevers and headaches to death. Current estimates place almost half the world’s population living in areas that are at-risk for infection by dengue and that area continues to expand over time. There are four distinct serotypes of dengue (DENV1, DENV2, DENV3, and DENV4). Disease severity from dengue infection is significantly worse if there is a secondary infection by a heterotypic serotype. The problems of increased severity with secondary infection as well as host immune response evasion by the virus itself have made vaccine development especially difficult. Analysis of complete polyprotein sequences of all four DENV serotypes revealed that all serotypes are currently subject to ongoing purifying selection and have experienced past purifying selection. However, several noteworthy exceptions within some genes of varying serotypes suggest conflicting evolutionary pressures. Most notably, the envelope (E) gene of DENV4 showed nucleotide polymorphism patterns suggestive of positive selection or relaxed purifying selection in its epitope regions. The E protein interacts directly with the host cell and is necessary for viral entry suggesting that its polymorphism pattern is indicative of evasion from immune system recognition. Both the NS1 gene of DENV2 and NS3 gene of DENV3, which are critical in viral replication, exhibited significantly higher medians of nonsynonymous gene diversity in their epitope regions implying escape mutations in these proteins as well. Significant conflicting ratios of πN (mean nonsynonymous nucleotide diversity) to πS (mean synonymous nucleotide diversity) between pairs of serotypes indicate that each individual serotype is under conflicting evolutionary pressures and help to explain the severity of secondary heterotypic infections. A comparison of three epitope prediction applications using datasets of both DENV genomes coupled with known cytotoxic T lymphocytes (CTL) DENV epitopes revealed significant differences in RANK and sensitivity measures of the programs. As these programs are used to predict which epitopes should be further studied in the creation of subunit vaccines, it was apparent that applications containing a combination of several prediction methods in concert are much more efficient than programs involving only one approach

Freshwater sponge hosts and their green algae symbionts: A tractable model to understand intracellular symbiosis

In many freshwater habitats, green algae form intracellular symbioses with a variety of heterotrophic host taxa including several species of freshwater sponge. These sponges perform important ecological roles in their habitats, and the poriferan:green algae partnerships offers unique opportunities to study the evolutionary origins and ecological persistence of endosymbioses. We examined the association between Ephydatia muelleri and its chlorophyte partner to identify features of host cellular and genetic responses to the presence of intracellular algal partners. Chlorella-like green algal symbionts were isolated from field-collected adult E. muelleri tissue harboring algae. The sponge-derived algae were successfully cultured and subsequently used to reinfect aposymbiotic E. muelleri tissue. We used confocal microscopy to follow the fate of the sponge-derived algae after inoculating algae-free E. muelleri grown from gemmules to show temporal patterns of symbiont location within host tissue. We also infected aposymbiotic E. muelleri with sponge-derived algae, and performed RNASeq to study differential expression patterns in the host relative to symbiotic states. We compare and contrast our findings with work in other systems (e.g., endosymbiotic Hydra) to explore possible conserved evolutionary pathways that may lead to stable mutualistic endosymbioses. Our work demonstrates that freshwater sponges offer many tractable qualities to study features of intracellular occupancy and thus meet criteria desired for a model system

Deletion of P2Y2 receptor reveals a role for lymphotoxin-α in fatty streak formation

Background Lymphotoxin alpha (LTα) is expressed in human atherosclerotic lesions and genetic variations in the LTα pathway have been linked to myocardial infarction. Activation of the P2Y2 nucleotide receptor (P2Y2R) regulates the production of LTα. in vitro. We aimed to uncover a potential pathway linking purinergic receptor to LTα-mediated inflammatory processes pivotal to the early stages of atherosclerosis in apolipoprotein E (ApoE−/−) deficient mice. Methods and results En face immunostaining revealed that P2Y2R and VCAM-1 are preferentially expressed in the atherosclerosis prone site of the mouse aortic sinus. Deletion of the P2Y2R gene suppresses VCAM-1 expression. Compared with ApoE−/− mice, ApoE−/− mice lacking the P2Y2R gene (ApoE−/−/P2Y2R−/−) did not develop fatty streak lesions when fed a standard chow diet for 15 weeks. Systemic and CD4+ T cell production of the pro-inflammatory cytokine lymphotoxin-alpha (LTα) were specifically inhibited in ApoE−/−/P2Y2R−/−mice. Anti-LTα preventive treatment was initiated in ApoE−/− mice with intraperitoneal administration of recombinant human tumor necrosis factor receptor 1 fusion protein (TNFR1-Fc) on 5 consecutive days before the disease onset. Remarkably, none of the TNFR1:Fc-treated ApoE−/− mice exhibited atherosclerotic lesions at any developmental stage. Significance ApoE−/− mice deficient in P2Y2R exhibit low endothelial cell VCAM-1 levels, decreased production of LTα and delayed onset of atherosclerosis. These data suggest that targeting this nucleotide receptor could be an effective therapeutic approach in atherosclerosis

Epidemiology of traumatic myiasis due to Chrysomya bezziana in Indonesia

&lt;p&gt;Epidemiology of traumatic myiasis in Indonesia was studied by the widespread collection of fly larvae from infested livestock in passive case detection surveys involving veterinary clinics. In addition, monthly data from Kediri regency in Eastern Java were analysed from 2006-2009 to explore the seasonality of myiasis. Larvae from a total of 260 cases from the nationwide survey and 341 cases from Kediri were identified. Except for 5 cases of chicken infestation due to Musca species in the nationwide survey, all other cases were exclusively caused by the Old World screwworm (OWS) fly, Chrysomya bezziana (Diptera: Calliphoridae). The monthly numbers of cases at Kediri were very variable, with cases in all months, but there was statistical evidence for an increase in cases in January and December, during the rainy season. The greatest numbers of infestations recorded were from cattle and goats. The most frequently infested sites nationwide and in Kediri were the vulva and umbilicus, associated with calving, which is a major risk period for traumatic myiasis. Mitochondrial DNA typing of 176 specimens was useful for detecting multiple infestations, but no association was found between genetic lineage and host. The equatorial climate of Indonesia, combined with poor husbandry systems are factors that help to support OWS fly development year round. Even if not considered a disease of strategic importance, screwworm myiasis remains a threat to livestock production in Indonesia and a major welfare issue that requires constant interventions by farmers. The new and collated epidemiological data presented represent the most extensive survey of traumatic myiasis in Indonesia to date and provide a valuable baseline to support integrated pest management programs.&lt;/p&gt;</jats:p

Assessment of the current status of real-world pharmacogenomic testing: informed consent, patient education, and related practices

Introduction: The practice of informed consent (IC) for pharmacogenomic testing in clinical settings varies, and there is currently no consensus on which elements of IC to provide to patients. This study aims to assess current IC practices for pharmacogenomic testing.Methods: An online survey was developed and sent to health providers at institutions that offer clinical germline pharmacogenomic testing to assess current IC practices.Results: Forty-six completed surveys representing 43 clinical institutions offering pharmacogenomic testing were received. Thirty-two (74%) respondents obtain IC from patients with variability in elements incorporated. Results revealed that twenty-nine (67%) institutions discuss the benefits, description, and purpose of pharmacogenomic testing with patients. Less commonly discussed elements included methodology and accuracy of testing, and laboratory storage of samples.Discussion: IC practices varied widely among survey respondents. Most respondents desire the establishment of consensus IC recommendations from a trusted pharmacogenomics organization to help address these disparities