Photoinduced chemiluminescence determination of carbamate pesticides

A liquid chromatography method with post-column photoinduced chemiluminescence (PICL) detection is proposed for the simultaneous determination of eight carbamate pesticides, namely aldicarb, butocarboxim, ethiofencarb, methomyl, methiocarb, thiodicarb, thiofanox and thiophanate-methyl. After chromatographic separation, quinine (sensitizer) was incorporated and the flow passed through an UV lamp (67 s of irradiation time) to obtain the photoproducts, which reacted with acidic Ce(IV) and provided a CL emission. The PICL method showed great selectivity for carbamate pesticides containing sulphur in their chemical structure. A solid-phase extraction process increased sensitivity (LODs ranging from 0.06 to 0.27 ng mL−1) and allowed the carbamate pesticides in surface and ground water samples to be determined, with recoveries in the range 87 110% (except for thiophanate-methyl, whose recoveries were between 60 and 75%). The intra- and inter-day precision was evaluated, with RSD ranging from 1.1 to 7.5% and from 2.6 to 12.3%, respectively. A discussion about the PICL mechanism is also included.Catalá-Icardo, M.; Meseguer-Lloret, S.; Torres-Cartas, S. (2016). Photoinduced chemiluminescence determination of carbamate pesticides. Photochemical and Photobiological Sciences. 15:626-634. doi:10.1039/c6pp00056hS62663415Santaladchaiyakit, Y., Srijaranai, S., & Burakham, R. (2012). Methodological aspects of sample preparation for the determination of carbamate residues: A review. Journal of Separation Science, 35(18), 2373-2389. doi:10.1002/jssc.201200431Pesticides in Ground and Drinking water, ed. M. Fielding, Water Pollution Research Report 27, Commission of the European Communities, Brussels, 1991Melchert, W. R., & Rocha, F. R. P. (2010). A greener and highly sensitive flow-based procedure for carbaryl determination exploiting long pathlength spectrophotometry and photochemical waste degradation. 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Analytical and Bioanalytical Chemistry, 400(2), 587-594. doi:10.1007/s00216-011-4781-1López-Paz, J. L., Catalá-Icardo, M., & Langa-Sánchez, A. (2014). Determination ofN-methylcarbamate pesticides using flow injection with photoinduced chemiluminescence detection. International Journal of Environmental Analytical Chemistry, 94(6), 606-617. doi:10.1080/03067319.2013.879295López-Paz, J. L., & Catalá-Icardo, M. (2011). Analysis of Pesticides by Flow Injection Coupled with Chemiluminescent Detection: A Review. Analytical Letters, 44(1-3), 146-175. doi:10.1080/00032719.2010.500788Huertas-Pérez, J. F., & García-Campaña, A. M. (2008). Determination of N-methylcarbamate pesticides in water and vegetable samples by HPLC with post-column chemiluminescence detection using the luminol reaction. Analytica Chimica Acta, 630(2), 194-204. doi:10.1016/j.aca.2008.09.047Pérez-Ruiz, T., Martínez-Lozano, C., & García, M. D. (2007). Determination of N-methylcarbamate pesticides in environmental samples by an automated solid-phase extraction and liquid chromatographic method based on post-column photolysis and chemiluminescence detection. Journal of Chromatography A, 1164(1-2), 174-180. doi:10.1016/j.chroma.2007.07.006Orejuela, E., & Silva, M. (2003). Monitoring some phenoxyl-type N-methylcarbamate pesticide residues in fruit juices using high-performance liquid chromatography with peroxyoxalate-chemiluminescence detection. Journal of Chromatography A, 1007(1-2), 197-201. doi:10.1016/s0021-9673(03)00934-8Catalá-Icardo, M., Lahuerta-Zamora, L., Torres-Cartas, S., & Meseguer-Lloret, S. (2014). Determination of organothiophosphorus pesticides in water by liquid chromatography and post-column chemiluminescence with cerium(IV). Journal of Chromatography A, 1341, 31-40. doi:10.1016/j.chroma.2014.03.024Galera, M. M., García, M. D. G., & Valverde, R. S. (2006). Determination of nine pyrethroid insecticides by high-performance liquid chromatography with post-column photoderivatization and detection based on acetonitrile chemiluminescence. Journal of Chromatography A, 1113(1-2), 191-197. doi:10.1016/j.chroma.2006.02.013Meseguer-Lloret, S., Torres-Cartas, S., Catalá-Icardo, M., & Gómez-Benito, C. (2015). Selective and Sensitive Chemiluminescence Determination of MCPB: Flow Injection and Liquid Chromatography. Applied Spectroscopy, 70(2), 312-321. doi:10.1177/0003702815620133Pesticide properties database (PPDB). University of Hertfordshire, http://sitem.herts.ac.uk/aeru/ppdb/en/index.htmPulgarín, J. A. M., Molina, A. A., & López, P. F. (2006). Automatic chemiluminescence-based determination of carbaryl in various types of matrices. Talanta, 68(3), 586-593. doi:10.1016/j.talanta.2005.04.051Waseem, A., Yaqoob, M., & Nabi, A. (2007). Flow-injection determination of carbaryl and carbofuran based on KMnO4–Na2SO3 chemiluminescence detection. 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Toxocariasis: a silent threat with a progressive public health impact

Background: Toxocariasis is a neglected parasitic zoonosis that afflicts millions of the pediatric and adolescent populations worldwide, especially in impoverished communities. This disease is caused by infection with the larvae of Toxocara canis and T. cati, the most ubiquitous intestinal nematode parasite in dogs and cats, respectively. In this article, recent advances in the epidemiology, clinical presentation, diagnosis and pharmacotherapies that have been used in the treatment of toxocariasis are reviewed. Main text: Over the past two decades, we have come far in our understanding of the biology and epidemiology of toxocariasis. However, lack of laboratory infrastructure in some countries, lack of uniform case definitions and limited surveillance infrastructure are some of the challenges that hindered the estimation of global disease burden. Toxocariasis encompasses four clinical forms: visceral, ocular, covert and neural. Incorrect or misdiagnosis of any of these disabling conditions can result in severe health consequences and considerable medical care spending. Fortunately, multiple diagnostic modalities are available, which if effectively used together with the administration of appropriate pharmacologic therapies, can minimize any unnecessary patient morbidity. Conclusions: Although progress has been made in the management of toxocariasis patients, there remains much work to be done. Implementation of new technologies and better understanding of the pathogenesis of toxocariasis can identify new diagnostic biomarkers, which may help in increasing diagnostic accuracy. Also, further clinical research breakthroughs are needed to develop better ways to effectively control and prevent this serious disease

Simultaneous lack of catalase and beta-toxin in Staphylococcus aureus leads to increased intracellular survival in macrophages and epithelial cells and to attenuated virulence in murine and ovine models

Staphylococcus aureus produces a variety of virulence factors that allow it to cause a wide range of infections in humans and animals. In the latter, S. aureus is a leading cause of intramammary infections. The contribution of catalase (KatA), an enzyme implicated in oxidative stress resistance, and beta-toxin (Hlb), a haemolysin, to the pathogenesis of S. aureus is poorly characterized. To investigate the role of these enzymes as potential virulence factors in S. aureus, we examined the intracellular survival of ΔkatA, Δhlb and ΔkatA Δhlb mutants in murine macrophages (J774A.1) and bovine mammary epithelial cells (MAC-T), and their virulence in different murine and ovine models. Catalase was not required for the survival of S. aureus within either J774A.1 or MAC-T cells. However, it was necessary for the intracellular proliferation of the bacterium after invasion of MAC-T cells. In addition, catalase was not needed for the full virulence of S. aureus in mice. Deletion of the hlb gene had no effect on the intracellular survival of S. aureus in J774A.1 cells but did cause a slight increase in survival in MAC-T cells. Furthermore, like catalase, beta-toxin was not required for complete virulence of S. aureus in murine models. Unexpectedly, the ΔkatA Δhlb mutant showed a notably increased persistence in both cell lines, and was significantly less virulent for mice than were the wild-type strain and single mutants. Most interestingly, it was also markedly attenuated in intramammary and subcutaneous infections in ewes and lambs. © 2009 SGM

Insect larvae biofactories as a platform for influenza vaccine production

Increased production capacity is one of the most important priorities for seasonal and pandemic influenza vaccines. In the present study, we used a baculovirus-insect larvae system (considered small, living biofactories) to improve the production of recombinant influenza virus H1N1 hemagglutinin (HA). Insect larvae produced four-fold more HA protein than insect cells per biomass unit (1 g of fresh larvae weight). A single infected Trichoplusia ni larva produced up to 113 μg of soluble and easily purified recombinant HA, an amount similar to that produced by 1.2 × 108 Sf21 insect cells infected by the same baculovirus. The use of the KDEL endoplasmic reticulum retention signal fused to the HA protein further increased recombinant protein production. Larvae-derived HA was immunogenically functional in vaccinated mice, inducing the generation of hemagglutination inhibition antibodies and a protective immune response against a lethal challenge with a highly virulent virus. The productivity, scalability and cost efficiency of small, living biofactories based on insect larvae suggest a broad-based strategy for the production of recombinant subunit vaccines against seasonal or pandemic influenza as an alternative to fermentation technologies. © 2011 Elsevier Inc. All rights reserved

Salmonella enterica serovar Choleraesuis derivatives harbouring deletions in rpoS and phoP regulatory genes are attenuated in pigs, and survive and multiply in porcine intestinal macrophages and fibroblasts, respectively.

Live attenuated Salmonella enterica strains have been extensively studied as potential vectors for the oral delivery of heterologous antigens. Due to its ability to target immune cells, its specific mechanism for crossing the intestinal barrier, and its swine-restricted tropism, S. enterica subspecies enterica serovar Choleraesuis (S. Choleraesuis) has attracted a great deal of interest for the production of bacterial-based oral carriers specifically adapted to swine. In this study, two mutants of S. Choleraesuis were constructed and their attenuation and intracellular fate analysed with the purpose of engineering new attenuated live strains with improved properties as oral vaccine carriers. Those strains harboured a specific deletion either within the phoP or rpoS genes, which encode virulence-related regulators in S. Typhimurium. In comparison to the wild-type parental S. Choleraesuis, the mutant strains, especially DeltaphoP, were extremely low in virulence in the murine model and in the natural host, the pig. Moreover, when compared with a commercial live vaccine strain, SC-54, the two mutants showed a higher level of attenuation in mice and DeltaphoP also in pigs. In addition, DeltarpoS and DeltaphoP presented a proliferation and survival phenotype within swine intestinal primary fibroblast and macrophage cell cultures, respectively. Collectively, the present results indicate that the DeltarpoS and DeltaphoP strains of S. Choleraesuis gather adequate features to be potential candidates for vaccine vectors for the specific delivery of heterologous antigens adapted to pigs

Salmonella enterica serovar Choleraesuis derivatives harbouring deletions in rpoS and phoP regulatory genes are attenuated in pigs, and survive and multiply in porcine intestinal macrophages and fibroblasts, respectively.

Live attenuated Salmonella enterica strains have been extensively studied as potential vectors for the oral delivery of heterologous antigens. Due to its ability to target immune cells, its specific mechanism for crossing the intestinal barrier, and its swine-restricted tropism, S. enterica subspecies enterica serovar Choleraesuis (S. Choleraesuis) has attracted a great deal of interest for the production of bacterial-based oral carriers specifically adapted to swine. In this study, two mutants of S. Choleraesuis were constructed and their attenuation and intracellular fate analysed with the purpose of engineering new attenuated live strains with improved properties as oral vaccine carriers. Those strains harboured a specific deletion either within the phoP or rpoS genes, which encode virulence-related regulators in S. Typhimurium. In comparison to the wild-type parental S. Choleraesuis, the mutant strains, especially DeltaphoP, were extremely low in virulence in the murine model and in the natural host, the pig. Moreover, when compared with a commercial live vaccine strain, SC-54, the two mutants showed a higher level of attenuation in mice and DeltaphoP also in pigs. In addition, DeltarpoS and DeltaphoP presented a proliferation and survival phenotype within swine intestinal primary fibroblast and macrophage cell cultures, respectively. Collectively, the present results indicate that the DeltarpoS and DeltaphoP strains of S. Choleraesuis gather adequate features to be potential candidates for vaccine vectors for the specific delivery of heterologous antigens adapted to pigs

Rational design of protamine nanocapsules as antigen delivery carriers

Current challenges in global immunization indicate the demand for new delivery strategies, which could be ap_x0002_plied to the development of new vaccines against emerging diseases, as well as to improve safety and efficacy of currently existing vaccine formulations. Here, we report a novel antigen nanocarrier consisting of an oily core and a protamine shell, further stabilized with pegylated surfactants. These nanocarriers, named protamine nanocapsules, were rationally designed to promote the intracellular delivery of antigens to immunocompetent cells and to trigger an efficient and long-lasting immune response. Protamine nanocapsules have nanometric size, positive zeta potential and high association capacity for H1N1 influenza hemagglutinin, a protein that was used here as a model antigen. The new formulation shows an attractive stability profile both, as an aqueous sus_x0002_pension or a freeze-dried powder formulation. In vitro studies showed that protamine nanocapsules were effi_x0002_ciently internalized by macrophages without eliciting significant toxicity. In vivo studies indicate that antigen_x0002_loaded nanocapsules trigger immune responses comparable to those achieved with alum, even when using sig_x0002_nificantly lower antigen doses, thus indicating their adjuvant properties. These promising in vivo data, alongside with their versatility for the loading of different antigens and oily immunomodulators and their excellent stability profile, make these nanocapsules a promising platform for the delivery of antigens. Chemical compounds: Protamine sulphate (PubChem SID: 7849283), Sodium Cholate (PubChem CID: 23668194), Miglyol (PubChem CID: 53471835), α tocopherol (PubChem CID: 14985), Tween® 20(PubChem CID: 443314), Tween® 80(PubChem CID: 5281955), TPGS (PubChem CID: 71406)

Highly versatile immunostimulating nanocapsules for specific immune potentiation

Aim To develop a new core-shell type (nanocapsules) adjuvant system composed of squalene and polyglucosamine (PG) and to evaluate its immunostimulant capacity. Results The defined PG nanocapsules exhibited the capacity to efficiently associate the selected antigens (recombinant hepatitis B surface antigen and hemagglutinin of influenza virus) onto their polymeric surface (70-75%), and the immunostimulant imiquimod within the oily core. The resulting nanovaccines, with a particle size of 200-250 nm and a positive zeta-potential (∼+60 mV), were able to significantly potentiate and modulate the immune response to the selected antigens upon intramuscular administration to mice. Their efficacy as novel adjuvants was attributed to their enhanced cell internalization and effective intracellular imiquimod/antigen delivery, together with their prolonged residence time at the injection site. Conclusion The nanocapsules described herein have the capacity to enhance, prolong and modulate the immune response of subunit antigens and, therefore, they could be proposed as a platform for the codelivery of different antigens and immunostimulators. © 2014 Future Medicine Ltd

Effects of ecological gradients on tropical avian haemoparasites

Diego Santiago-Alarcón y Alfonso Marzal (eds.); Primera Edición; 910 páginasThis chapter provides a brief overview of how natural gradients (e.g., latitude, altitude, and landscape gradients) affect host–parasite interactions involving blood parasites in wildlife and how biotic and abiotic factors act as disruptors. These gradients have a direct impact on prevalence, parasitemia, and the observed relationships between parasites and hosts. In the tropical zone, altitudinal gradients imitate the behavior of the latitudinal gradient, since low temperatures are common at both higher altitudes and higher latitudes. Temperature is one of the determining factors of the diversity of vectors, hosts, and vegetation that affect parasite transmission cycles. Furthermore, within landscapes, there may be many types of elements producing gradients. For instance, increasing distance from water sources, anthropogenic degradation, and even sequential stages of succession and interspersion of vegetation communities would affect host–parasite–vector interactions. However, such effects do not always operate in the same direction because responses are context sensitive. We also discuss the importance of an integrative diagnosis, using microscopic and molecular approaches, which allow better approximations and analyses at the parasite species level, thus producing stronger conclusions. The same detail is recommended for studies on the hematophagous fauna of potential vectors. The life cycle of different parasite species has its own set of characteristics, and it corresponds to the researchers to unravel the puzzle and to avoid unwarranted generalizations.The work of SM is supported by project PGC2018-097426-B-C21 from the Spanish Ministry of Science, Innovation, and Universities. The work of LC-V was funded by the National Council for Science and Technology of Mexico (CONACYT; grants SEP-CB-2012-1-183377, and PDCPN-2015-1-1628).Peer reviewe