Responses of aquatic insect functional diversity to landscape changes in Atlantic forest

The Atlantic Forest domain, one of the 25 world's hotspots for biodiversity, has experienced dramatic changes in its landscape. While the loss of species diversity is well documented, functional diversity has not received the same amount of attention. In this study, we evaluated functional diversity of insects in streams utilizing three indices: functional diversity (FD), functional dispersion (FDis), and functional divergence (FDiv), seeking to understand the roles of three predictor sets in explaining functional patterns: (1) bioclimatic and landscape variables; (2) spatial variables; and (3) local environmental variables. We determined the amount of variation in different measures of functional diversity that was explained by each predictor set and their interplays using variation partitioning. Our study showed that variation in functional diversity is better explained by a set of variables linked to different scales dependent on spatial structures, indicating the importance of landscape and mainly environmental variables in the functional organization of aquatic insect communities, and that the relative importance of predictor sets depends on the indices considered. Variation in FD was better explained by the interplay among the three predictor sets and by local environmental variables, whereas variation in FDis was better explained by spatial variables and by the interplay between environmental and spatial variables. Variation in FDiv was not significantly explained by any predictors. Our study adds more evidence on the harmful effects caused by landscape changes on biodiversity in the Atlantic Forest, suggesting that these effects also influence the functional organization of stream insect communities. © 2013 The Author(s) Journal compilation © 2013 by The Association for Tropical Biology and Conservation.

Plant-derived essential oils affecting settlement and oviposition of Bemisia tabaci (Genn.) biotype B on tomato

The silverleaf whitefly Bemisia tabaci (Genn.) biotype B (Hemiptera: Aleyrodidae) is an economically important pest of tomatoes Solanum lycopersicum (L.), causing irregular ripening on fruits and transmitting several plant pathogenic geminiviruses. The management of this pest is commonly based on repetitive spraying with synthetic pesticides, causing serious environmental damages and increase of resistance by insect population. In the present study, essential oils from the leaves of Artemisia camphorata Vill., Ageratum conyzoides L., Foeniculum vulgare Mill., Lippia alba (Mill.) N. E. Br., Plectranthus neochilus Schltr., and Tagetes erecta L. were investigated for their possible repellent and oviposition-deterrent effects against B. tabaci biotype B on tomato. In a multi-choice assay, P. neochilus essential oil was the most active repellent and oviposition deterrent. Essential oils of A. conyzoides and T. erecta significantly deterred the female B. tabaci biotype B from laying eggs on treated tomato leaflets compared with the control. (E)-Caryophyllene (30.67 %) and the monoterpenes α-pinene (15.02 %) and α-thujene (11.70 %) were identified as the major constituents of the essential oil of P. neochilus. Our findings demonstrated the potential of essential oil of P. neochilus and other oils in the reduction of settlement and oviposition of B. tabaci biotype B on tomato. © 2012 Springer-Verlag Berlin Heidelberg.

T and B lymphocytes in the brains of dogs with concomitant seropositivity to three pathogenic protozoans: Leishmania chagasi, Toxoplasma gondii and Neospora caninum

Background: Visceral leishmaniasis is a disease with great variability regarding the clinical manifestations in humans and dogs. Chronically infected dogs may develop neurological disorders, however, there are few reports that characterize the lesions and make clear the pathogenesis of the canine cerebral leishmaniasis. Concomitant with Leishmania chagasi, dogs may be infected by opportunistic pathogens, such as Toxoplasma gondii and Neospora caninum, which may contribute to the occurrence of lesions in the central nervous system. Hence, we aimed to compare the T and B lymphocytes population in the brains of infected dogs with seropositivity to L. chagasi, T. gondii and N. caninum concurrently (n = 24), seropositivity only to L. chagasi (n = 31), and seropositivity to T. gondii and N. caninum (n = 16). Uninfected dogs were used as control (n = 10). Results: Inflammatory lesions, characterised by mononuclear cell accumulation, composed mainly of CD3+ T lymphocytes predominated in several encephalic regions of the dogs from all the three infected groups, with no difference among them (P = 0.0004), whereas CD79α+ B lymphocytes were detected in very small intensity and presented no difference among groups (P = 0.5313). Furthermore, no association among diseases was detected at the serological enquire. Conclusions: We demonstrate that the peripheral infection by L. chagasi per se can promote the influx of lymphocytes within the nervous milieu as occurs during Toxoplasma and Neospora infections, and the concomitant seropositivity against these pathogens does not exacerbate the inflammatory brain lesions. Therefore, these findings give additional support that the brain should be included in the list of organs affected by visceral leishmaniasis and that even asymptomatic infected dogs may develop brain lesions. © 2013 Sakamoto et al.; licensee BioMed Central Ltd.

A survey of DNA methylation across social insect species, life stages, and castes reveals abundant and caste-associated methylation in a primitively social wasp

DNA methylation plays an important role in the epigenetic control of developmental and behavioral plasticity, with connections to the generation of striking phenotypic differences between castes (larger, reproductive queens and smaller, non-reproductive workers) in honeybees and ants. Here, we provide the first comparative investigation of caste- and life stage-associated DNA methylation in several species of bees and vespid wasps displaying different levels of social organization. Our results reveal moderate levels of DNA methylation in most bees and wasps, with no clear relationship to the level of sociality. Strikingly, primitively social Polistes dominula paper wasps show unusually high overall DNA methylation and caste-related differences in site-specific methylation. These results suggest DNA methylation may play a role in the regulation of behavioral and physiological differences in primitively social species with more flexible caste differences. © 2013 Springer-Verlag Berlin Heidelberg.

The role of prophage in plant-pathogenic bacteria

A diverse set of phage lineages is associated with the bacterial plant-pathogen genomes sequenced to date. Analysis of 37 genomes revealed 5,169 potential genes (approximately 4.3 Mbp) of phage origin, and at least 50 had no function assigned or are nonessential to phage biology. Some phytopathogens have transcriptionally active prophage genes under conditions that mimic plant infection, suggesting an association between plant disease and prophage transcriptional modulation. The role of prophages within genomes for cell biology varies. For pathogens such as Pectobacterium, Pseudomonas, Ralstonia, and Streptomyces, involvement of prophage in disease symptoms has been demonstrated. In Xylella and Xanthomonas, prophage activity is associated with genome rearrangements and strain differentiation. For other pathogens, prophage roles are yet to be established. This review integrates available information in a unique interface (http://propnav.esalq.usp.br) that may be assessed to improve research in prophage biology and its association with genome evolution and pathogenicity. © Copyright ©2013 by Annual Reviews. All rights reserved.

Action of the insect growth regulator fluazuron, the active ingredient of the acaricide Acatak®, in Rhipicephalus sanguineus nymphs (Latreille, 1806) (Acari: Ixodidae)

The present study evaluated the efficacy of fluazuron (active ingredient of the acaricide Acatak®) and its effects on Rhipicephalus sanguineus nymphs fed on rabbits exposed to different doses of this insect growth regulator. Three different doses of fluazuron (20 mg/kg, 40 mg/kg, and 80 mg/kg) were applied on the back of hosts (via pour on), while distilled water was applied to the Control group. On the first day of treatment with fluazuron (24 h), hosts were artificially infested with R. sanguineus nymphs. Once fully engorged, nymphs were removed and placed in identified Petri dishes in Biochemical Oxygen Demand (BOD) incubator for 7 days. After this period, engorged nymphs were processed for ultramorphological analysis. The results revealed alterations in the ultramorphology of many chitinous structures (smaller hypostome and chelicerae, less sclerotized scutum, fewer sensilla, fewer pores, absence of grooves, marginal and cervical strips and festoons in the body, even the anal plaque was damaged) that play essential roles for the survivor of ticks and that can compromise the total or partial development of nymphs and emergence of adults after periodic molting. Our findings confirm the efficacy of fluazuron, a more specific and less aggressive chemical to the environment and human health, and that does not induce resistance, in nymphs of the tick R. sanguineus in artificially infested rabbits treated with this arthropod growth regulator (AGR), indicating that it could be used in the control of this stage of the biological cycle of the tick R. sanguineus. © 2013 Wiley Periodicals, Inc.

Paratrichodina africana (Ciliophora): A pathogenic gill parasite in farmed Nile tilapia

Trichodinids are ciliated protozoa that are widely known as one of the main groups of fish parasites. The genus Trichodina presents the greatest species diversity. However, records of Paratrichodina species are scarce, and little is known about their pathogenicity in hosts. The present study provides new records of Paratrichodina africana Kazubski and El-Tantawy (1986) in Nile tilapia from South America and descriptions of pathological changes and seasonality. A total of 304 farmed fish were examined. From gill scraping, parasites were identified using Klein's nitrate impregnation method. Gill samples were fixed for histopathological analysis. Small trichodinid found in this study have a prominent blade apophysis and narrow central part and blade shape that corresponds to the characteristics of P. africana Kazubski and El-Tantawy (1986). Gill lesions were proportional to parasite intensity, in which the gill tissue was compromised in heavy infestation. Proliferative disturbances were found, including epithelial hyperplasia, desquamation, and mononuclear and eosinophilic infiltrate that culminated in necrosis. We did not observe a seasonality effect on the occurrence of P. africana. This ciliated protozoan causes compromised respiratory capacity that leads to severe gill lesions and currently is an important pathogen that afflicts intensive tilapia cultures in Brazil. © 2013 Elsevier B.V.

Estudo da microbiota fúngica gastritestinal de morcegos (Mammala, Chiroptera) da região noroeste do estado de São Paulo: potencial zoonótico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização patogênica e molecular de isolados de Beauveria sp e Matarhizium sp de diferentes regiões do Brasil para o contole de Diatraea saccharalis Fabricius (Leídoptera: Crambidae)

Pós-graduação em Microbiologia - IBILCE

Susceptibilidade das fases do ciclo de vida de Diatraea saccharalis (Lepidoptera: Crambidae) à ação de fungos entomopatogênicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)