Prevalence of Salmonella in Eggs from Conventional and Cage-Free Egg Production Systems and the Role of Consumers in Reducing Household Contamination.

Salmonella is one of the leading causes of foodborne disease worldwide, usually related to contaminated poultry or poultry products, such as eggs. Since egg contamination with Salmonella depends on multiple factors that make it challenging to control, consumers' knowledge about food safety and the proper handling of eggs is crucial. The aims of the study were (1) to determine the prevalence of Salmonella in eggs from conventional and alternative production systems, (2) to characterize the Salmonella isolates according to phenotypic-genotypic and antimicrobial-resistant traits, and (3) to understand how consumers manage the hazards related to egg contamination in the household. A total of 426 egg samples were analyzed (conventional systems = 240; alternative systems = 186). Culture-based and molecular microbiological methods were used to identify Salmonella and bioinformatics analysis of whole genome sequences was used to determine the serotype and antimicrobial-resistant genes. Salmonella enterica serotype Enteritidis was detected only in eggs from alternative systems (1.1%, 2/186). Isolates showed resistance to nalidixic acid (100%, 2/2), and the aac(6')-Iaa gene and a mutation in the gyrA gene were identified in both isolates. Overall, consumers demonstrated knowledge regarding food safety; however, many still engage in practices that pose a risk of acquiring foodborne illnesses.

Human Trafficking Efforts to Protect Connecticut's Vulnerable Children and Youth: Incorporating the Voices of Community Practitioners.

Research demonstrates a growing number of exploited and trafficked children in the United States, but few studies address how practitioners continue to respond to these issues. Multiple efforts identify victims of human trafficking and provide services since the passing of the Trafficking Victims Protection Act (TVPA) in 2000 and its reauthorization. However, the TVPA oftentimes failed to protect the most vulnerable. This qualitative study included four focus group sessions with 28 practitioners from various disciplines (e.g., social work, healthcare, legal) to examine how the state of Connecticut has expanded services and programs for children and youth trafficking victims. The findings describe current statewide partnerships along with challenges and successes when working with child victims of human trafficking, offering practice and policy recommendations.

The prediction of swarming in honeybee colonies using vibrational spectra.

In this work, we disclose a non-invasive method for the monitoring and predicting of the swarming process within honeybee colonies, using vibro-acoustic information. Two machine learning algorithms are presented for the prediction of swarming, based on vibration data recorded using accelerometers placed in the heart of honeybee hives. Both algorithms successfully discriminate between colonies intending and not intending to swarm with a high degree of accuracy, over 90% for each method, with successful swarming prediction up to 30 days prior to the event. We show that instantaneous vibrational spectra predict the swarming within the swarming season only, and that this limitation can be lifted provided that the history of the evolution of the spectra is accounted for. We also disclose queen toots and quacks, showing statistics of the occurrence of queen pipes over the entire swarming season. From this we were able to determine that (1) tooting always precedes quacking, (2) under natural conditions there is a 4 to 7 day period without queen tooting following the exit of the primary swarm, and (3) human intervention, such as queen clipping and the opening of a hive, causes strong interferences with important mechanisms for the prevention of simultaneous rival queen emergence.

Respuesta de cultivares de Musa spp. al estrés hídrico in vitro inducido con polietilenglicol 6000 / Responses of Musa spp. cultivars to in vitro water stress induced with polyethylene glycol 6000

RESUMEN Los plátanos y bananos son cultivos sensibles al déficit hídrico. Las sequías cada vez más prolongadas sugieren la necesidad de obtener plantas tolerantes a este factor; la selección temprana de estas plantas, comparada con la selección en campo, permite ahorrar tiempo y trabajar con mayores volúmenes de individuos. Para ello es conveniente contar con cultivares patrones cuya respuesta al déficit hídrico in vitro sea favorable. El objetivo del presente trabajo fue determinar la respuesta de cultivares de Musa spp. con diferente composición genómica al estrés hídrico inducido in vitro con polietilenglicol 6000 (PEG-6000). Se estudiaron los cultivares 'Pelipita' (ABB), 'Manzano' (AAB) y 'Grande naine' (AAA). El estrés se indujo con 30 g/L de PEG-6000 en medio de cultivo semisólido de multiplicación. A los 30 días se evaluaron variables indicadoras de estrés morfológicas (altura y número de brotes por explante), fisiológicas (masa fresca y masa seca) y bioquímicas (contenido prolina, peróxido de hidrógeno y malondialdehido). En el cultivar 'Pelipita' se afectó solamente la altura de las plantas, mientras que en los demás se afectaron todas las variables excepto la masa seca en el 'Manzano'. En este último y en el 'Grande naine' se incrementó la prolina, el peróxido de hidrógeno y el malondialdehido, lo que evidenció un mayor estrés oxidativo y daño en las membranas celulares. Los cultivares estudiados, pudieran emplearse como controles de tolerancia ('Pelipita') y sensibilidad ('Grande naine' y 'Manzano') en la selección in vitro de plantas tolerantes a la sequía, en futuros programas de mejoramiento genético.

ABSTRACT Bananas and plantains are crops very sensitive to water deficit. Increasingly prolonged drought condition suggests the need for tolerant plants to this factor. The early selection of these plants in in vitro conditions save time and allow working with large volumes of individuals. This requires having genotypes with favorable response to in vitro water deficit. The aim of this work was to determine the response of Musa spp. cultivars, with different genotype contribution, to in vitro water stress induced by polyethylene glycol 6000 (PEG-6000). Cultivars 'Pelipita' (ABB), 'Manzano' (AAB) and 'Grande naine' (AAA) were cultured in semisolid multiplication medium supplemented with PEG-6000 30 g/L. Different stress indicator traits were evaluated after 30 days (morphological: height and number of shoots per explant; physiological: fresh and dry weight; and biochemical: proline, hydrogen peroxide and malondialdehyde content). As results, osmotic stress affected only plant height in 'Pelipita' cultivar. However, in the other cultivars all variables were affected, except dry weight in 'Manzano'. Moreover cv. 'Grande naine' and 'Manzano' increased proline, hydrogen peroxide and malondialdehyde content. These results indicate that osmotic pressure could induce oxidative stress and cell membrane damages in these cultivars. The obtained results suggested that these genotypes could be used as a tolerant ('Pelipita') and sensitive ('Grande naine' and 'Manzano') controls in in vitro selection of drought-tolerant plants in future breeding programs.

Honeybee Colony Vibrational Measurements to Highlight the Brood Cycle.

Insect pollination is of great importance to crop production worldwide and honey bees are amongst its chief facilitators. Because of the decline of managed colonies, the use of sensor technology is growing in popularity and it is of interest to develop new methods which can more accurately and less invasively assess honey bee colony status. Our approach is to use accelerometers to measure vibrations in order to provide information on colony activity and development. The accelerometers provide amplitude and frequency information which is recorded every three minutes and analysed for night time only. Vibrational data were validated by comparison to visual inspection data, particularly the brood development. We show a strong correlation between vibrational amplitude data and the brood cycle in the vicinity of the sensor. We have further explored the minimum data that is required, when frequency information is also included, to accurately predict the current point in the brood cycle. Such a technique should enable beekeepers to reduce the frequency with which visual inspections are required, reducing the stress this places on the colony and saving the beekeeper time.

Organophosphate Resistance and its Main Mechanism in Populations of Codling Moth (Lepidoptera: Tortricidae) from Central Chile.

The codling moth, Cydia pomonella (L.), is the key pest of apple production worldwide. Insecticide resistance has been reported in all producing countries, based on five different mechanisms. Codling moth in Chile has resistance to azinphos-methyl and tebufenozide in post-diapausing larvae. However, there are no studies about the susceptibility of these populations to insecticides from other chemical groups. Therefore, the efficacy of azinphos-methyl, chlorpyrifos-ethyl, esfenvalerate, methoxyfenozide, tebufenozide, and thiacloprid on neonate and post-diapausing larvae from six field populations was investigated, and identified resistance mechanisms in this species were evaluated. Neonate larvae were susceptible to all insecticides studied, but post-diapausing larvae from four populations were resistant to chlorpyrifos, one of them was also resistant to azinphos-methyl, and another one was resistant to tebufenozide. The acetylcholinesterase insensitivity mutation was not detected, and the sodium channel knockdown resistance mutation was present in a low frequency in one population. Detoxifying enzymatic activity of glutathione S-transferases, esterases, and cytochrome P-450 monooxygenases in adults differed among populations, but chlorpyrifos resistance was associated only with a decreased esterase activity as shown by a significant negative correlation between chlorpyrifos mortality and esterase activity.

The tomato borer, Tuta absoluta, invading the Mediterranean Basin, originates from a single introduction from Central Chile.

The Lepidopteran pest of tomato, Tuta absoluta, is native to South America and is invasive in the Mediterranean basin. The species' routes of invasion were investigated. The genetic variability of samples collected in South America, Europe, Africa and Middle East was analyzed using microsatellite markers to infer precisely the source of the invasive populations and to test the hypothesis of a single versus multiple introductions into the old world continents. This analysis provides strong evidence that the origin of the invading populations was unique and was close to or in Chile, and probably in Central Chile near the town of Talca in the district of Maule.

Excision of a selectable marker gene in transgenic banana using a Cre/lox system controlled by an embryo specific promoter.

Antibiotic and herbicide resistance genes have been used in transgene technology as powerful selection tools. Nonetheless, once transgenic events have been obtained their presence is no longer needed and can even be undesirable. In this work, we have developed a system to excise the selectable marker and the cre recombinase genes from transgenic banana cv. 'Grande Naine' (Musa AAA). To achieve this, the embryo specific REG-2 promoter was isolated from rice and its expression pattern in banana cell clumps, somatic embryos and regenerated plantlets was characterized by using a pREG2::uidA fusion construct. Subsequently, the REG-2 promoter was placed upstream of the cre gene, conferring Cre functionality in somatic embryos and recombination of lox sites resulting in excision of the selectable marker and cre genes. PCR analysis revealed that 41.7 % of the analysed transgenic plants were completely marker free, results that were thereafter confirmed by Southern blot hybridization. These results demonstrate the feasibility of using developmentally controlled promoters to mediate marker excision in banana. This system does not require any extra handling compared to the conventional transformation procedure and might be useful in other species regenerating through somatic embryogenesis.

Heat shock induced excision of selectable marker genes in transgenic banana by the Cre-lox site-specific recombination system.

Selectable marker genes are indispensable for efficient production of transgenic events, but are no longer needed after the selection process and may cause public concern and technological problems. Although several gene excision systems exist, few have been optimized for vegetatively propagated crops. Using a Cre-loxP auto-excision strategy, we obtained transgenic banana plants cv. Grande Naine (Musa AAA) devoid of the marker gene used for selection. We used T-DNA vectors with the cre recombinase gene under control of a heat shock promoter and selectable marker gene cassettes placed between two loxP sites in direct orientation, and a gene of interest inserted outside of the loxP sites. Heat shock promoters pGmHSP17.6-L and pHSP18.2, from soybean and Arabidopsis respectively, were tested. A transient heat shock treatment of primary transgenic embryos was sufficient for inducing cre and excising cre and the marker genes. Excision efficiency, as determined by PCR and Southern hybridization was 59.7 and 40.0% for the GmHSP17.6-L and HSP18.2 promoters, respectively. Spontaneous excision was not observed in 50 plants derived from untreated transgenic embryos. To our knowledge this is the first report describing an efficient marker gene removal system for banana. The method described is simple and might be generally applicable for the production of marker-free transgenic plants of many crop species.

Efecto de la densidad de inoculación en la formación y morfología de los embriones somáticos de plátano (Musa spp. AAAB, cv. híbrido FHIA-21) / Effect of inoculum density on formation and morphology of plantain somatic embryos (Musa spp. AAAB, cv. Hybrid ‘FHIA-21’)

La embriogénesis somática constituye una interesante propuesta para la propagación masiva de plantas del cultivar híbrido FHIA-21 (Musa AAAB). Sin embargo, se caracteriza por ser un proceso asincrónico, dado por la presencia de embriones somáticos en diferentes etapas de desarrollo ontogénico. La reducción de la asincronía es un aspecto importante para la utilización de este sistema de regeneración en la propagación de plantas. Esta investigación se realizó con el objetivo de determinar el efecto de la densidad de inoculación sobre la formación y el desarrollo morfológico homogéneo de los embriones somáticos del cv. FHIA-21. Con este propósito se adicionaron 0,5; 1,0; 1,5 y 2,0 g de masa fresca (gMF) de agregados celulares embriogénicos en Erlenmeyers (250 ml), que contenían 30 ml de medio de cultivo líquido. Las evaluaciones se realizaron a los 30 días de cultivo con la determinación del número y la longitud de los embriones somáticos (mm). Además de una descripción morfológica e histológica de estos. Los resultados mostraron el efecto regulatorio de la densidad de inoculación en la formación y el desarrollo morfológico de los embriones somáticos. La mayor formación de embriones con un desarrollo morfológico homogéneo se produjo en 1,5 gMF de densidad de inoculación. Esta proporcionó un 86,4% de embriones con una longitud de 0,21 a 4,0 mm, y el estudio de las secciones histológicas mostró evidencias histológicas de la etapa globular. La sincronización durante la formación y el desarrollo de los embriones somáticos del cv. FHIA-21 aumentó la eficiencia del proceso de embriogénesis somática.

Somatic embryogenesis is an interesting proposal for mass propagation of plants from the FHIA-21 (Musa AAAB). However, it is characterized by an asynchronous process, due to the presence of somatic embryos at different stages of ontogenetic development. Reduction of asynchrony is an important aspect to use this system of regeneration in plant propagation. Effect of inoculation density on the formation and uniform morphological development of somatic embryos of cv. ‘FHIA-21’ was determine by adding 0.5, 1.0, 1.5 and 2.0 g of fresh mass (gMF) of embryogenic cell aggregates, in Erlenmeyer flasks (250 ml) containing 30 ml liquid culture medium. Evaluations were made within 30 days of culture determining the number and length of somatic embryos (mm). Also, morphological and histological descriptions of these were analyzed. Results showed the regulatory effect of inoculation density on the formation and morphological development of somatic embryos. The biggest formation of embryos with a uniform morphological development occurred in 1.5 gMF inoculation density. This provided 86.4% of embryos with a length of 0.21 to 4.0 mm and the study of histological sections showed histological evidence of the globular stage. Synchronization during the formation and development of somatic embryos cv. FHIA-21 increased the efficiency of somatic embryogenesis.

Bacillus cereus y su implicación en la inocuidad de los alimentos: parte II / Bacillus cereus and its involvement in food safety: part II

Bacillus cereus da lugar a un síndrome diarreico y a uno emético, similares a los producidos por otros microbios transmitidos por alimentos. Se evalua la presencia de B cereus en alimentos asociados a brotes de origen alimentario y se precisa su implicación como agente causal. Se estudiaron 108 muestras relacionadas con 57 brotes producidos en Ciudad de La Habana desde el 2004 al 2007. La enumeración de B cereus se realizó según la ISO 7932:2004 y la NC 38-02-12:1988. Ademàs se investigó: Staphylococcus coagulasa positiva (NC ISO 6888-1:2003), Clostridium perfringens (NC 38-02-11:1988 e ISO 7937:2004) y Salmonella (ISO 6579:2002); así como, coliformes totales (NC ISO 4832:2002), coliformes fecales y Escherichia coli (NC 38-02-14:1989)...

Bacillus cereus causes diarrheal and emetic syndromes similar to those provoked by other foodborne pathogens. Objetives: To evaluate the presence of B cereus in foodstuffs associated to outbreaks and to find out if it is the causative agent. One hundred eight suspected food samples associated to 57 outbreaks were analyzed using ISO 7932:2004 and Cuban standard no. 38-02-12:1988. Also other microorganisms such as positive Staphylococci coagulase(Cuban standard ISO 6888-1:2003), Clostridium perfringens (Cuban standard 38-02-11:1988 and ISO 7937:2004) and Salmonella (ISO 6579:2002) as well as total coliforms (ISO 4832:2002), fecal coliforms and Escherichia coli (Cuban standard 38-02-14:1989)...

Bacillus cereus y su implicación en la inocuidad de los alimentos: parte II / Bacillus cereus and its involvement in food safety: part II

Bacillus cereus da lugar a un síndrome diarreico y a uno emético, similares a los producidos por otros microbios transmitidos por alimentos. Se evalua la presencia de B cereus en alimentos asociados a brotes de origen alimentario y se precisa su implicación como agente causal. Se estudiaron 108 muestras relacionadas con 57 brotes producidos en Ciudad de La Habana desde el 2004 al 2007. La enumeración de B cereus se realizó según la ISO 7932:2004 y la NC 38-02-12:1988. Ademàs se investigó: Staphylococcus coagulasa positiva (NC ISO 6888-1:2003), Clostridium perfringens (NC 38-02-11:1988 e ISO 7937:2004) y Salmonella (ISO 6579:2002); así como, coliformes totales (NC ISO 4832:2002), coliformes fecales y Escherichia coli (NC 38-02-14:1989)...(AU)

Bacillus cereus causes diarrheal and emetic syndromes similar to those provoked by other foodborne pathogens. Objetives: To evaluate the presence of B cereus in foodstuffs associated to outbreaks and to find out if it is the causative agent. One hundred eight suspected food samples associated to 57 outbreaks were analyzed using ISO 7932:2004 and Cuban standard no. 38-02-12:1988. Also other microorganisms such as positive Staphylococci coagulase(Cuban standard ISO 6888-1:2003), Clostridium perfringens (Cuban standard 38-02-11:1988 and ISO 7937:2004) and Salmonella (ISO 6579:2002) as well as total coliforms (ISO 4832:2002), fecal coliforms and Escherichia coli (Cuban standard 38-02-14:1989)...(AU)

Incidencia de Listeria spp en hortalizas frescas / Incidence of Listeria spp in fresh vegetables

Listeria monocytogenes es un patógeno que puede transmitirse por el consumo de hortalizas, en Cuba no se conoce su incidencia en estos alimentos. Evaluar la presencia de Listeria spp y el efecto de los procedimientos de limpieza, en hortalizas frescas comercializadas en Ciudad de La Habana. Se estudió Listeria spp en 86 muestras, mediante el método rápido de Oxoid (1999) y los métodos ISO 11290-1/1996 e ISO 11290-2/1998, se realizó enriquecimiento en frío y pruebas bioquímicas complementarias. Se determinaron indicadores de calidad sanitaria, coliformes (NC ISO 4832/2002) y coliformes fecales (NC 38-02-14/1989). Se comprobó la presencia o no de la bacteria después del proceso de limpieza, en muestras positivas a Listeria spp y en muestras inoculadas con Listeria monocytogenes. En frijolitos chinos, lechuga, zanahoria, col y cebollino se detectó Listeria spp por la prueba rápida; sólo en las tres últimas muestras se aisló L innocua, en concentraciones <102/g. Estas muestras presentaron coliformes >103/g y dos de ellas, coliformes fecales >102/g. Después del proceso de limpieza no se detectó la bacteria en cebollino y zanahoria positivos a L innocua, mientras que en lechuga y zanahoria inoculadas con L monocytogenes, sólo se redujo la carga microbiana. Se comprobó que no es suficiente el proceso tradicional de limpieza para eliminar L monocytogenes a menos que se halle en bajas concentraciones. La única especie identificada fue L innocua, que no constituye un riesgo para la salud. Las muestras positivas a Listeria spp no poseen una buena calidad sanitaria.

Listeria monocytogenes is a pathogen that can be vegetable-borne. Its incidence on this type of food is unknown in Cuba. To evaluate the presence of Listeria spp and the effect of cleaning methods in fresh vegetables on sale in the City of Havana. Eighty six samples were analyzed by using Rapid Test Oxoid (1999) and the traditional ISO 11290-1 (1996) and ISO 11290-2 (1998) methods. Also additional biochemical tests and cold enrichment to 4 ºC, were made. Health quality indicators, coliforms (NC ISO 4832/2002) and faecal coliforms (NC 38-02-14/1989) were determined. The presence or absence of bacteria after the cleaning process was determined in samples positive to Listeria spp and in contaminated samples with Listeria monocytogenes. Listeria spp was detected by the rapid test in lettuce, carrot, cabbage and scallion; Listeria innocua was isolated in the last three ones at<102 UFC/g concentrations. These samples showed coliforms at>103/g concentrations and two of them faecal coliforms at>102/g. After the cleaning process, no bacteria was detected in previously L innocua positive carrot and scallion samples whereas in lettuce and carrot samples innoculated with L. monocytogenes and cleaned, the level of this microorganism was just reduced. It was confirmed that the traditional cleaning process to eliminate L monocytogenes is not enough unless this bacterium is present at low concentrations. The only isolated species L innocua was not a health risk. Listeria spp positive samples did not have good sanitary quality.

Incidencia de Listeria spp en hortalizas frescas / Incidence of Listeria spp in fresh vegetables

Listeria monocytogenes es un patógeno que puede transmitirse por el consumo de hortalizas, en Cuba no se conoce su incidencia en estos alimentos. Evaluar la presencia de Listeria spp y el efecto de los procedimientos de limpieza, en hortalizas frescas comercializadas en Ciudad de La Habana. Se estudió Listeria spp en 86 muestras, mediante el método rápido de Oxoid (1999) y los métodos ISO 11290-1/1996 e ISO 11290-2/1998, se realizó enriquecimiento en frío y pruebas bioquímicas complementarias. Se determinaron indicadores de calidad sanitaria, coliformes (NC ISO 4832/2002) y coliformes fecales (NC 38-02-14/1989). Se comprobó la presencia o no de la bacteria después del proceso de limpieza, en muestras positivas a Listeria spp y en muestras inoculadas con Listeria monocytogenes. En frijolitos chinos, lechuga, zanahoria, col y cebollino se detectó Listeria spp por la prueba rápida; sólo en las tres últimas muestras se aisló L innocua, en concentraciones <102/g. Estas muestras presentaron coliformes >103/g y dos de ellas, coliformes fecales >102/g. Después del proceso de limpieza no se detectó la bacteria en cebollino y zanahoria positivos a L innocua, mientras que en lechuga y zanahoria inoculadas con L monocytogenes, sólo se redujo la carga microbiana. Se comprobó que no es suficiente el proceso tradicional de limpieza para eliminar L monocytogenes a menos que se halle en bajas concentraciones. La única especie identificada fue L innocua, que no constituye un riesgo para la salud. Las muestras positivas a Listeria spp no poseen una buena calidad sanitaria(AU)

Listeria monocytogenes is a pathogen that can be vegetable-borne. Its incidence on this type of food is unknown in Cuba. To evaluate the presence of Listeria spp and the effect of cleaning methods in fresh vegetables on sale in the City of Havana. Eighty six samples were analyzed by using Rapid Test Oxoid (1999) and the traditional ISO 11290-1 (1996) and ISO 11290-2 (1998) methods. Also additional biochemical tests and cold enrichment to 4 ºC, were made. Health quality indicators, coliforms (NC ISO 4832/2002) and faecal coliforms (NC 38-02-14/1989) were determined. The presence or absence of bacteria after the cleaning process was determined in samples positive to Listeria spp and in contaminated samples with Listeria monocytogenes. Listeria spp was detected by the rapid test in lettuce, carrot, cabbage and scallion; Listeria innocua was isolated in the last three ones at<102 UFC/g concentrations. These samples showed coliforms at>103/g concentrations and two of them faecal coliforms at>102/g. After the cleaning process, no bacteria was detected in previously L innocua positive carrot and scallion samples whereas in lettuce and carrot samples innoculated with L. monocytogenes and cleaned, the level of this microorganism was just reduced. It was confirmed that the traditional cleaning process to eliminate L monocytogenes is not enough unless this bacterium is present at low concentrations. The only isolated species L innocua was not a health risk. Listeria spp positive samples did not have good sanitary quality(AU)

Resistance monitoring in codling moth: a need for standardization.

BACKGROUND: A wide range of methods has been used for monitoring resistance in Cydia pomonella L. However, the results from specific tests are not always concordant and they generate doubts over the extent to which the data represent the field situation. Therefore, the variability in the expression of resistance mechanisms and in resistance ratios between developmental stages and their reliability in a field situation were studied. RESULTS: Neonate larvae showed the highest insecticide resistance, except to spinosad. Resistance ratios were from 2 to 9.5, depending on the insecticide and the strain tested, when compared with the susceptible strain. Spinosad exhibited the highest resistance ratio for diapausing larvae (4.4, 12.2 and 4.4 for Raz, Rdfb and RDelta strains, respectively). Enzymatic ratios were higher in adults than in neonates or diapausing larvae, and the highest enzymatic ratios were observed for mixed-function oxidases (7.3-36.7 for adults of resistant strains). CONCLUSIONS: The sensitivity of different instars depends on the insecticides used, and there is a differential expression of resistance mechanisms between stages. For the population considered in this study, tests on neonates provided the most consistent results to the field situation, but adult response to chlorpyrifos-ethyl and azinphos-methyl in the laboratory was also consistent with the field results.

Diversity of insecticide resistance mechanisms and spectrum in European populations of the codling moth, Cydia pomonella.

Only a few of the registered insecticides against Cydia pomonella L. are still effective in areas where insecticide resistance has emerged in this pest. Resistance mechanisms are multiple, and their lone or cumulative effects in a single population are not completely understood. A detailed estimation of resistance spectrum is still required to define the suitable insecticides to use against a given population. The efficacy of ten insecticides was therefore investigated together with the resistance mechanisms expressed in four laboratory strains and 47 field populations of C. pomonella from five countries. Bioassays were performed using topical applications of diagnostic concentrations on diapausing larvae, and resistance mechanisms were analysed on adults emerging from control insects. All populations exhibited a reduced susceptibility to at least one insecticide when compared with the susceptible laboratory strain. Cross-resistances were observed between azinphos-methyl or phosalone and more recent compounds such as spinosad and thiacloprid. Resistances to azinphos-methyl, diflubenzuron, spinosad, tebufenozide and thiacloprid were significantly correlated with mixed-function oxidase activity, while increased glutathione-S-transferase and reduced non-specific esterase activities were correlated with resistance to azinphos-methyl and emamectin, respectively. Conversely, resistances to azinphos-methyl, tebufenozide and thiacloprid were negatively correlated with increased esterase activity. None of the observed mechanisms explained the loss of susceptibility of populations to chlorpyrifos-ethyl, and no significant correlation was detected between resistance to deltamethrin and the presence of the kdr mutation. The suitability of such non-target instars to monitor insecticide resistance in field populations is discussed.

Evaluation of azinphos-methyl resistance and activity of detoxifying enzymes in codling moth (Lepidoptera: Tortricidae) from central Chile.

Regular applications of insecticides have been the main management practice against codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae) in Chile. Organophosphates are the most widely used insecticides, and azinphos-methyl is an important element in spray programs. In particular, we evaluated diagnostic doses of azinphos-methyl on neonate and postdiapausing larvae from seven apple (Malus spp.) orchards. We also evaluated the activity of detoxifying enzymes, such as glutathione S-transferases (GSTs), cytochrome P450 polysubstrate monooxygenases (PSMOs), and esterases, which are likely to be involved in resistance to insecticides. Such responses were compared with an insecticide-susceptible strain that has been maintained in the laboratory for several years. Neonate larval mortality of field populations to azinphos-methyl was not significantly different from of the susceptible strain. In contrast, postdiapause larval mortality was significantly lower in the six analyzed populations than in the susceptible strain. The C. pomonella populations with reduced postdiapause mortality to azinphos-methyl also showed statistically higher GST activity. Finally, no significant differences were found in total esterase or PSMO activity between C. pomonella populations. Therefore, the observed reduction in postdiapause larval mortality to azinphos-methyl seems to be associated with an increase in GST activity.

Acetylcholinesterase mutation in an insecticide-resistant population of the codling moth Cydia pomonella (L.).

Two strains of Cydia pomonella (L.) (Lepidoptera: Tortricidae) were selected in the lab by exposure to increasing concentrations of diflubenzuron (Rdfb strain) or azinphos-methyl (Raz strain). Insecticide bioassays showed that the adults of the Rdfb strain exhibited a 2.6-fold and a 7.7-fold resistance ratio to azinphos-methyl and carbaryl, respectively compared to a susceptible strain (S) whereas the adults of the Raz strain exhibited a 6.7-fold resistance ratio to azinphos-methyl and a 130-fold resistance ratio to carbaryl. In the Raz strain, a target site resistance mechanism was suggested by the inhibition of acetylcholinesterase (AChE) activity. In fact the ki values did not discriminate the S and Rdfb strains, while the Raz strain exhibited a 1.7-fold and a 14-fold increase in ki value compared to the S strain for azinphos-methyl oxon and carbaryl, respectively. To verify this hypothesis, two cloned AChE cDNAs sequences (named cydpom-ace2 e cydpom-ace1) were compared between the susceptible and the resistant strains. No difference in the deduced amino acid sequence was found in cydpom-ace2 (orthologous to the Drosophila melanogaster AChE). In the putative cydpom-ace1 (paralogous to the Drosophila AChE), a single amino acid substitution F399V was exclusively present in the Raz strain. The F399 lined the active site of the enzyme and the F399V substitution likely could influence the accessibility of different types of inhibitors to the catalytic site of the insensitive cydpom-ace1.

Determinación de Listeria spp. en quesos y embutidos comercializados en Cuba / Determination of Listeria spp in cheese and sausages sold in Cuba

La Listeria monocytogenes es un patógeno emergente causante de una enfermedad transmitida a través de los alimentos conocida como listeriosis, que cursa de forma grave y generalmente deja secuelas en las personas que la sobreviven. La detección de la L. monocytogenes en los alimentos de mayor riesgo, como son los listos para el consumo reviste gran importancia. En el presente trabajo se determinó la incidencia de la Listeria en 54 muestras de quesos y 98 de embutidos y ahumados, comercializados en Cuba. Se aplicó un método tradicional para la detección cualitativa y cuantitativa de la L. monocytogenes según la Norma UNE-EN ISO 11290-1 (1997) y el Draft International Standard ISO/DIS 11290-2 (1995), además se realizaron pruebas bioquímicas adicionales para la identificación de otras especies de Listeria. Para la detección cualitativa de la Listeria también se aplicó una prueba de diagnóstico rápido. La L. monocytogenes se aisló en queso azul, en salchichón y mortadela; la L. innocua: en queso frescal y queso cubanito, en chorizo, longaniza magro y morcilla y la L. welshimeri: en salchichas. Las dos especies halladas en salchichón se encontraron asociadas a una misma muestra. En otras tres muestras (pollo ahumado, chorizo, mortadela) se detectó la Listeria por la prueba rápida, sin lograr el aislamiento por el método tradicional, lo cual se debe a la mayor sensibilidad del primer método. La enumeración resultó < 102 UFC/g de alimento en todos los casos. La utilización de la técnica cualitativa permitió demostrar la presencia de la L. monocytogenes en tres de las muestras analizadas lo cual limita estos productos para su comercialización y consumo