Effects of microbial conditioning and temperature on the leaf-litter shredding activity of Phylloicussp

Few studies try to explain the effects in tropical lotic ecosystems of an increase in water temperature on the shredding activity of invertebrate shredders, particularly in association with the quality of the leaf litter and the degree of litter conditioning. Therefore, the aims of this study were as follows: i) to better understand how this key invertebrate shredder group affects the decomposition of different species of leaf litter under gradual increases in temperature and microbial conditioning; and ii) to verify the possible consequences on leaf mass loss (LML). Three species of leaf litter were used in two experiments. Inexperiment I, the litters of three species (Protium spruceanum, Richeria grandisand Ingalaurina) at three conditioning levels (1, 7, 14 days) were tested under five different temperatures (20, 22, 24, 26 and28°C). In experiment II, the leaf litters of three species were used, without conditioning, under four temperatures (20, 22, 26 and27°C). The shredding performed by Phylloicussp. was largely dependent on the lignin and cellulose concentrations in each leaf species, independent of conditioning. The presence or absence of conditioning may cause the shredders to use different energy compensation strategies in response to the temperature increases.

Genome misclassification of Klebsiella variicola and Klebsiella quasipneumoniae isolated from plants, animals and humans / Clasificación errónea de aislados de Klebsiella variicola y Klebsiella quasipneumoniae obtenidos de plantas, animales y humanos

Abstract: Objective: Due to the fact that K. variicola, K. quasipneumoniae and K. pneumoniae are closely related bacterial species, misclassification can occur due to mistakes either in normal biochemical tests or during submission to public databases. The objective of this work was to identify K. variicola and K. quasipneumoniae genomes misclassified in GenBank database. Materials and methods: Both rpoB phylogenies and average nucleotide identity (ANI) were used to identify a significant number of misclassified Klebsiella spp. genomes. Results: Here we report an update of K. variicola and K. Quasipneumoniae genomes correctly classified and a list of isolated genomes obtained from humans, plants, animals and insects, described originally as K. pneumoniae or K. variicola, but known now to be misclassified. Conclusions: This work contributes to recognize the extensive presence of K. variicola and K. quasipneumoniae isolates in diverse sites and samples.

Resumen: Objetivo: Identificar genomas mal clasificados de K. variicola, y K. quasipneumoniae en la base de datos del GenBank. Material y métodos: En el presente estudio se usaron tanto análisis filogenéticos usando rpoB como la identidad media de nucleótidos (ANI, por sus siglas en ingles) para identificar un número significativo de genomas del género Klebsiella. Resultados: Se reportó una actualización de genomas de K. variicola y K. quasipneumoniae correctamente clasificados y una lista de aquellos aislamientos obtenidos de seres humanos, plantas, animales e insectos, descritos originalmente como K. pneumoniae o K. variicola pero ahora se conoce que están mal clasificados. Conclusiones: Este trabajo contribuye a la presencia extensiva de aislamientos de K. variicola y K. quasipneumoniae en diversos sitios y muestras.

Organización y conservación de la colección de hongos patógenos y simbiontes de insectos y otros artrópodos del CEPAVE (CONICET-UNLP), La Plata, Argentina / Organization and preservation of the collection of pathogenic and fungal symbionts of insects and other arthropods from CEPAVE (CONICET-UNLP), La Plata, Argentina

La colección de hongos patógenos y simbiontes de insectos y otros artrópodos del Centro de Estudios Parasitológicos y de Vectores es única por sus características específicas en la Argentina y por preservar hongos en cultivo, in vitro e in vivo. Esta colección está abierta para actividades de investigación, docencia, servicios y asesoramiento público y privado. Un total de 421 aislamientos pertenecientes a 23 géneros (Ascomycota: 16, Entomophthoromycotina: 4 Glomeromycota: 2 y Oomycota: 1) son preservados en la colección mediante diversos métodos: criopreservación en freezer a −20 °C y −70 °C, agua destilada estéril, papel, arena y liofilización. Las cepas que integran la colección fueron aisladas de insectos y de otros artrópodos; y a partir de suelo (usando insectos trampa o aislamiento directo en medios selectivos). La identificación se realizó mediante estudios de caracterización morfológicos y, en algunos casos, por taxonomía molecular. Esta colección se utiliza como centro de referencia para identificación de especies, certificaciones, estudios de investigación y docencia, transferencia tecnológica, servicios a terceros, depósito de cepas y preservación de la diversidad y conservación del germoplasma. Las cepas preservadas son, en su mayor parte, nativas de distintas regiones de la Argentina. La colección fue originada en el año 1988 y está registrada en la base de la Federación Latinoamericana de Colecciones de Cultivos y en la World Federation of Culture Collections.

The collection of fungal pathogens and symbionts of insects and other arthropods of the Centro de Estudios Parasitológicos y de Vectores, La Plata, Argentina, is unique because it preserves in vivo and in vitro cultures of fungal pathogens. This culture collection is open for research, teaching, consulting services, and strain deposit. It contains 421 strains belonging to 23 genera (16 Ascomycota, 4 Entomophthoromycotina, 2 Glomeromycota and 1 Oomycota), and the cultures are preserved by different methods such as cryopreservation in freezer at −20 °C and −70 °C, paper, distilled water and lyophilization. Fungi were isolated from insects, other arthropods, and soil (by using insect baits and selective media). Species were identified by morphological features and in a few strains by molecular taxonomy (PCR of rDNA). This collection is a reference center for species identification/certifications, research and teaching purposes, strain deposit, transference and consultancy services, and its overall goal is to preserve the fungal germplasm and ex situ diversity. Most of the strains are native of Argentina. The collection was originated in 1988 and is registered in the Latin American Federation for Culture Collections and in the World Federation of Culture Collections.

Isolation, pathogenicity and disinfection of Staphylococcus aureus carried by insects in two public hospitals of Vitória da Conquista, Bahia, Brazil

Currently, hospital infection is a serious public health problem, and several factors may influence the occurrence of these infections, including the presence of insects, which are carriers of multidrug-resistant bacterial species. The aim of this study was to isolate staphylococci carried by insects in two public hospitals of Vitoria da Conquista, Bahia and to identify the resistance profile, pathogenicity and efficacy of disinfection of the premises. A total of 91 insects were collected in 21 strategic points of these hospitals, and 32 isolated strains ofStaphylococcus aureus were isolated. Based on antibiogram and Minimum Inhibitory Concentration results, 95% of these strains were susceptible to oxacillin. These strains were also evaluated for the presence of resistance genes encoding resistance to oxacillin/methicillin by polymerase chain reaction, but the sample was negative for this gene. Pathogenicity tests were performed in vitro biofilm formation induced by glucose, where it was found that eight (27.58%) strains were classified as biofilm producers and 21 (72.4%) as stronger producers. In addition, we performed PCR for their virulence genes: Sea (enterotoxin A), SEB (B), Sec (C), PVL (Panton-Valentine Leukocidin), ClfA (clumping factor A) and Spa (protein A). Of these, Sea, Spa PVL were positive in 7 (21.8%), 2 (6.3%) and 1 (3.1%) samples, respectively. The analysis of cytokine induction in the inflammatory response of J774 macrophages by isolates from the two hospitals did not show statistical difference at the levels of IL-6, TNF-α, IL-1 and IL-10 production. In addition, we verified the antimicrobial activity of disinfecting agents on these strains, quaternary ammonium, 0.5% sodium hypochlorite, 1% sodium hypochlorite, 2% sodium hypochlorite, 2% glutaraldehyde, Lysoform®, 70% alcohol solution of chlorhexidine digluconate, 2% peracetic acid, and 100% vinegar. Resistance was seen in only for the following two disinfectants: 70% alcohol in 31 (96.8%) samples tested and vinegar in 30 (93.8%) samples. The study demonstrated the presence of resistant and pathogenic organisms conveyed by insects, thus suggesting improvement in efforts to control these vectors.

Non-biting flying insects as carriers of pathogenic bacteria in a Brazilian hospital

Introduction Insects have been described as mechanical vectors of nosocomial infections. Methods Non-biting flying insects were collected inside a pediatric ward and neonatal-intensive care unit (ICU) of a Brazilian tertiary hospital. Results Most (86.4%) of them were found to carry one or more species of bacteria on their external surfaces. The bacteria isolated were Gram-positive bacilli (68.2%) or cocci (40.9%), and Gram-negative bacilli (18.2%). Conclusions Insects collected inside a hospital were carrying pathogenic bacteria; therefore, one must consider the possibility they may act as mechanical vectors of infections, in especially for debilitated or immune-compromised patients in the hospital environments where the insects were collected. .

Frequency of infection with A and B supergroup Wolbachia in insects and pests associated with mulberry and silkworm.

Wolbachia is a ubiquitous, Gram-negative,vertically transmitted, alpha-proteobacterium that causes an array of reproductive abnormalities including cytoplasmic incompatibility, feminization of genetic males, parthenogenesis in a number of insect species, among others. Wolbachia is now being exploited as an agent for pest and vector control. Previous surveys indicated that it is commonly seen in 16-76% of arthropods. In this paper, using polymerase chain reaction assay based on specific amplification of the ftsZ -A and -B supergroup Wolbachia gene fragments, we found that 30% of insects and pests screened were positive for Wolbachia. Among them 66.7% harbour double Wolbachia infection, while 33.3 % harbour single Wolbachia infection. These results indicate widespread infection with both double and single Wolbachia, and provide a wealth of information to exploit this endobacterium for the management of pests and vectors.

Avaliação dos fatores de risco no processamento de café verde para o aparecimento de ocratoxina A (OTA) / Evaluation of the risk factors in the processing of green coffee for the appearance of ochratoxin A (OTA)

Dentre os perigos relacionados com a produção de café verde, a ocratoxina A (OTA) é considerada significativa nesse produto. Com o objetivo de estudar a origem da OTA no processamento de café verde e avaliar os possíveis fatores de risco (região, etapas do processamento, fungos, insetos e ácaros) que poderiam contribuir na presença de OTA, foram amostradas três fazendas nos seguintes municípios: Bom Jardim (RJ), Espírito Santo do Pinhal (SP) e Cornélio Procópio (PR), onde havia a produção de café verde pela via seca e úmida. Foram coletadas 109 amostras de grãos de café, em diversas etapas do processamento, no período de maio a agosto de 2002. As amostras foram colhidas de acordo com fluxograma estabelecido e as etapas estudadas foram: cereja (campo), via seca, via úmida, armazém e café de varrição. Dessas amostras, 10 apresentaram OTA, que variou na sua quantificação de 3 a 101 ng.g –1. A maior prevalência de OTA foi a do café de varrição 57%, a via úmida apresentou uma prevalência de 10,3% e a via seca 7%. Na etapa cereja o fungo potencialmente toxigênico mais encontrado foi Penicillium spp, e quanto aos insetos, as larvas de Diptera e os Homoptera; na via úmida foram encontradas linhagens do Aspergillus seção Nigri e Circundatti e Penicillium spp, a infestação predominante foi a broca do café e os ácaros da família Acaridae; na etapa via seca registrou-se o isolamento de fungos do gênero Penicillium spp e Asperigillus seção Nigri, a broca do cadê foi a infestação predominante junto com os ácaros da família Acaridae, na etapa de armazém foram isolados Penicillium spp e Aspergillus seção Nigri, o inseto predominante foi a boca do café e os ácaros da família Acaridae; no café de varrição foram isolados Penicillium spp e Asperigillus seção Nigri e a broca do café estava presente junto com insetos da Ordem Díptera...

The ochratoxin A (OTA) is considered to be among the most significant coffee contaminants with related hazards. With the purpose to study the origin of the OTA in the processing of green coffee and to evaluate the possible risk factors (region, step of processing, fungi, insects and mites) that could contribute in the OTA presence, had been selected three regions (states) of Brazil: Bom Jardim/RJ, Espírito Santo do Pinhal/SP and Cornélio Procópio/PR. A total of 109 samples of coffee beans were collected in conformity with flow chart established at different stages of ripening and processing: cherry (field), dry method, wet method, and warehouse and varrição coffee, from May to August of 2002. Of these samples 10 had presented OTA, which varied in its quantification from 3 to 101 ng.g-1. The biggest prevalence of OTA was the varrição coffee 57%, the wet method presented a prevalence of 10,3% and dry way 7%. In the stage cherry fungi potentially toxigenic was more found Penicillium spp, the insects had been the larvae of Diptera and the Homoptera; in the wet way it was found Aspergillus section Nigri and Circundatti and Penicillium spp, the predominant infestation was the coffee berry borer and the mite of the Acaridae family; in the stage wet methods spp was registered the isolation the Penicillium spp and Aspergillus section Nigri, the predominant infestation was the coffee berry borer together with the mites of the Acaridae family; in the stage of warehouse had been isolated Penicillium spp and Aspergillus section Nigri, and the predominant insect was the coffee berry borer and mites of the family Acaridae; in the varrição coffee had been isolated Penicillium spp and Aspergillus section Nigri the coffee berry borer was the most present insects together of Diptera. The results of each step had been with compared by Analysis of Variance. In the analysis of risk factors the varrição coffee" was the factor most strongly related to the risk of the presence of OTA (p<0,001 ).

Hongos patógenos de insectos en Argentina (Zygomycetes: Entomophthorales) / Pathogenic fungi of insects from Argentina (Zygomycetes: Entomophthorales)

Three species of Entomophthorales entomopathogenic fungi (Zygomycotina: Zygomycetes) have been identified from insects in agricultural crops (Buenos Aires Province, Argentina): Zoophthora radicans Batko (Brefeld); Entomophthora planchoniana Cornu and Pandora gammae (Weiser) Humber. Fungal structure measurements are reported.

Se informa de tres especies de hongos Entomophthorales en insectos encontrados en cultivos agrícolas en la Provincia de Buenos Aires, Argentina: Zoophthora radicans Batko (Brefeld); Entomophthora planchoniana Cornu y Pandora gammae (Weiser) Humber. Se incluyen las medidas de las estructuras fúngicas.

Suitability of leguminous cover crop pollens as food source for the green lacewing Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)

Diversification of crops with species that provide suitable pollen for predators may reduce pest population on crops by enhancing predator effectiveness. In this paper we evaluated the suitability of leguminous cover crop pollens to the predatory green lacewing Chrysoperla externa (Hagen). The predator is commonly found in coffee agroecosystems and the plant species tested were pigeon pea and sunn hemp, which are used in organic coffee systems. Newly emerged females and males of C. externa were reared on diets containing pollen of pigeon pea, sunn hemp, or castor bean, used as a control. The reproductive success of C. externa was evaluated when females fed the pollen species and when honey was added to the diets, to verify the predator need for an extra carbohydrate source. Similar intrinsic growth rates were found for females fed on pigeon pea pollen and on sunn hemp pollen but these rates increased significantly when honey was added to the diets. Females fed with pigeon pea pollen plus honey and with sunn hemp pollen plus honey had higher intrinsic growth rates than those fed with castor bean pollen plus honey. Females fed on castor bean pollen only or on honey only, did not oviposit. Leguminous pollen species were equally suitable for C. externa especially when they were complemented with honey. The results suggest that to successfully enhance predator effectiveness, organic coffee plantation should be diversified with plant providing pollen in combination with plant providing nectar.

A diversificação das culturas com plantas que forneçam pólen nutricionalmente adequado para predadores pode reduzir a população de pragas pelo aumento da efetividade dos predadores. Neste trabalho, avaliou-se a viabilidade nutricional de polens de leguminosas utilizadas como adubação verde, para o crisopídeo Chrysoperla externa (Hagen), comumente encontrado em agroecossistemas cafeeiros. Os adubos verdes testados foram guandu e crotalária, leguminosas utilizadas em sistemas orgânicos de café. Adultos de C. externa recém-emergidos foram criados em dietas contendo pólen de guandu, de crotalária e de mamona (controle). O sucesso reprodutivo de C. externa foi avaliado nas dietas de pólen e quando mel foi adicionado ao pólen, para se verificar a necessidade do predador por fonte extra de carboidratos. A taxa de crescimento populacional do predador foi semelhante nas dietas de pólen de guandu e de crotalária. No entanto, a taxa aumentou significativamente quando mel foi adicionado às dietas. Fêmeas alimentadas com pólen de guandu e mel e com pólen de crotalária e mel tiveram crescimento superior ao das alimentadas com pólen de mamona e mel. Fêmeas alimentadas somente com pólen de mamona ou somente com mel não ovipositaram. Os polens de guandu e de crotalária foram igualmente adequados para C. externa, especialmente quando foram complementados com mel. Os resultados sugerem que para aumentar a efetividade dos predadores, os sistemas orgânicos de café deveriam ser diversificados com plantas que forneçam pólen em combinação com plantas que forneçam néctar.

Sporulation of "Metarhizium anisopliae" var. "acridum" and "Beauveria bassiania" on "Rhammatocerus schistocercoides" under humid and dry conditions

The sporulation of the fungi "Metarhizium anisopliae" var. "acridum" and "Beauveria bassiana" in cadavers of the grasshopper "Rhammatocerus schistocercoides" was studied in dry and humid environments. Both fungi were equally virulent against "R. schistocercoides". However, internally, "M. anisopliae" produced more conidia than "B. bassiana" at 53(per cent) and 75(per cent) relative humidity. Externally, there was no sporulation at 53(per cent) and 75(per cent) RH, and "M. anisopliae" produced more conidia than "B. bassiana" at 100(per cent) RH.

Sujidades leves em sopas desidratadas: adequaçäo de um método microscópico / Light filth in dried foods: microscopic method evaluation

Para deteçäo de sujidades leves em sopas desidratadas foi proposta a metodologia descrita pela AOAC 980.27 para cevada, aveia e mistura de cereais desidratados. As amostras foram contaminadas artificialmente com fragmentos de insetos: cabeça, tórax-abdomen e élitros, ácaros e pêlos de ratos brancos. Na etapa de desengorduramento e flutuaçäo o método foi modificados quando comparou-se os efeitos de dois solventes, isopropanol 40(por cento) indicado na metodologia AOAC 980.27, etanol 60(por cento) e misturas deles nas proporçöes 1:1 e 3:1, respectivamente. A média de recuperaçäo de sujidades leves, utilizando isopropanol 40(por cento) e etanol 60(por cento) (3:1) foi de: 92,6(por cento) para fragmentos de insetos, 43(por cento) para ácaros e 53(por cento) para pêlos de roedores, näo diferindo significativamente (p>0,05), quando utilizou-se somente o isopropanol 40(por cento); encontrando-se 93,3(por cento para fragmentos de insetos, 39(por cento) para ácaros e 61(por cento) para pêlos de roedores. O método 980.27 modificado, utilizando isopropanol 40(por cento) e etanol 60(por cento) (3:1) foi mais eficiente para a recuperaçäo de fragmentos de insetos. A avaliaçäo das sujidades leves, em sopas desidratadas, no método proposto modificado empregando-se a soluçäo de isopropanol 40(por cento) e etanol 60 por cento (3:1), foi realizada em 62 amostras comerciais de duas marcas diferentes (A e B), produzidas no Estado de Säo Paulo e adquiridas em supermercados do município de Araraquara-SP. O total de amostras foi dividido em dois lotes com 31 unidades cada, constituídos por amostras do mesmo tipo, mesma marca e datas de fabricaçäo diferentes. As amostras foram analisadas em duplicata. A maior incidência de sujidades leves (n§/50g), foi para fragmentos de insetos com porcentagens de 81,8(por cento) (1 a 36 fragmentos de insetos) para a marca A e 82,5(por cento) (1 a 49 fragmentos de insetos) para a marca B. As duas marcas mostraram pequena incidência ácaros e pêlos de ruedores. Estes resultados sugerem que é necessário a revisäo da legislaçäo brasileira, quanto aos limites microscópicos, em sopas desidratadas

Influence of pH on the toxicity and survival of total cells and spores of Bacillus thuringiensis

Entre los grupos de microorganismos que se estudian por su potencial entomopatógeno, B. thuringiensis (Bt) es sin lugar a dudas la bacteria de mayor importancia en el control de insectos, plagas y vectores. En este trabajo se estudió la patogenicidad y sobrevivencia de células totales y de esporas de tres cepas de B. thuringiensis autóctonas de suelos argentinos (A61, A27 y A68) y una cepa comercial HD-1, a distintas concentraciones de ión hidrógeno (pH=4,4; 5,4;7,4; 8,4; 9,4 y 10,4), bajo condiciones de laboratorio. No se observó disminución de la toxicidad de las cepas desarrolladas a distintos valores de pH en bioensayos contra Cydia pomonella. El mayor efecto antimicrobiano sobre el número de esporas y células totales se detectó a pH 4,4. El pH 5,4 fue el que permitió un mayor índice de sobrevivencia en los serotipos investigados. Tres cepas de Bt (A61,A27,HD-1) mostraron alta toxicidad contra C. pomonella. El serotipo sotto, sin embargo, no produjo ese efecto

Activation of adenyl cyclase in insect midgut membrane vesicles by bacillus thuringiensis delta endotoxins and melittin

Addition of Bacillus thuringiensis aizawai ICI toxins to brush-border membrane vesicles, prepared from Pieris brassicae midgut, increased cyclic AMP which was paralleled by activation of adenylate cyclase in direct measurements. Bee venom toxin melittin, which is cytolytic, also increased cyclic AMP in these vesicles. It is proposed that activation of adenylate cyclase may be due to alteration of its lipid environment by these toxins