Alkane-grown Beauveria bassiana produce mycelial pellets displaying peroxisome proliferation, oxidative stress, and cell surface alterations

The entomopathogenic fungus Beauveria bassiana is able to grow on insect cuticle18 hydrocarbons as the sole carbon source, inducing several enzymes involved in alkane19 assimilation and concomitantly increasing virulence against insect hosts. In this study, we20 describe some physiological and molecular processes implicated in growth, nutritional21 stress response, and cellular alterations found in alkane-grown fungi. The fungal cytology22 was investigated using light and transmission electron microscopy (TEM) while the surface23 topography was examined using atomic force microscopy (AFM). Fungal hydrophobicity24 was also measured on the cell surface. Additionally, the expression pattern of several genes25 associated with oxidative stress, peroxisome biogenesis, and hydrophobicity were analysed26 by qPCR. We found a novel type of growth in alkane-cultured B. bassiana similar to27 mycelial pellets described in other alkane-free fungi, which were able to germinate and28 produce viable conidia in media without a carbon source and to be pathogenic against29 larvae of the beetles Tenebrio molitor and Tribolium castaneum. Optical microscopy and30 TEM showed that pellets were formed by hyphae cumulates with high peroxidase activity,31 exhibiting peroxisome proliferation and an apparent surface thickening. Alkane-grown32 conidia appeared to be more hydrophobic and cell surfaces displayed different topography33 than glucose-grown cells, as it was observed by AFM. We also found a significant34 induction in several genes encoding for peroxins, catalases, superoxide dismutases, and35 hydrophobins. These results show that both morphological and metabolic changes are36 triggered in mycelial pellets derived from alkane-grown B. bassiana.Fil: Huarte Bonnet, Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Santos Da Paixao, Flavia Regina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Ponce, Juan C. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Santana, Marianela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Prieto, Eduardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Pedrini, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; Argentin

Alkane-grown <i>Beauveria bassiana</i> produce mycelial pellets displaying peroxisome proliferation, oxidative stress, and cell surface alterations

The entomopathogenic fungus Beauveria bassiana is able to grow on insect cuticle hydrocarbons as the sole carbon source, inducing several enzymes involved in alkane assimilation and concomitantly increasing virulence against insect hosts. In this study, we describe some physiological and molecular processes implicated in growth, nutritional stress response, and cellular alterations found in alkane-grown fungi. The fungal cytology was investigated using light and transmission electron microscopy (TEM) while the surface topography was examined using atomic force microscopy (AFM). Fungal hydrophobicity was also measured on the cell surface. Additionally, the expression pattern of several genes associated with oxidative stress, peroxisome biogenesis, and hydrophobicity were analysed by qPCR. We found a novel type of growth in alkane-cultured B. bassiana similar to mycelial pellets described in other alkane-free fungi, which were able to germinate and produce viable conidia in media without a carbon source and to be pathogenic against larvae of the beetles Tenebrio molitor and Tribolium castaneum. Optical microscopy and TEM showed that pellets were formed by hyphae cumulates with high peroxidase activity, exhibiting peroxisome proliferation and an apparent surface thickening. Alkane-grown conidia appeared to be more hydrophobic and cell surfaces displayed different topography than glucose-grown cells, as it was observed by AFM. We also found a significant induction in several genes encoding for peroxins, catalases, superoxide dismutases, and hydrophobins. These results show that both morphological and metabolic changes are triggered in mycelial pellets derived from alkane-grown B. bassiana.Instituto de Investigaciones Bioquímicas de La PlataInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Diet and Feeding Behavior of the Horned Guan (Oreophasis derbianus) in Mexico

The Horned Guan (Oreophasis derbianus) is endemic to humid montane forests of southern Mexico and Guatemala. This species is considered endangered because of their small populations, the loss and fragmentation of habitat, illegal trade, and overexploitation by subsistence hunters. We update information about the species' diet and foraging behavior by integrating the results generated during two and a half decades of research on the Horned Guan's ecology at the El Triunfo Biosphere Reserve, in Chiapas, Mexico, with additional published information compiled from other areas. Based on nearly 450 hrs of direct observations of free-ranging guans and 530 discrete feeding events, we found that during the breeding season Horned Guans feed primarily on fruits from six species of plants and leaves from one species. Horned Guans were not observed eating animal matter, corroborating its specialized frugivore-folivore habits. Our study increases the known plant taxa found in the Horned Guan's diet in El Triunfo from 40 to 63 (Supplemental Material), and globally to 101 species (Supplemental Material). For 48 taxa in El Triunfo, only fruits were consumed, while for eleven taxa consumption was restricted to leaves, and to flowers for one species; for four taxa both fruits and leaves were consumed. We found significant differences between males and females in the location of foraging on trees and diet composition. Young birds are fed fruits of Citharexylum mocinnii and leaves of Solanum appendiculatum by their mothers, both of which are rare in the diet of adult males. The conservation of the Horned Guan requires the long-term protection of suitable habitat that maintains the plant species important in their diet

Determination of meloxicam in human plasma administrated with four drugs by LC method: application to a pilot bioavailability study

The development and validation of a simple and accurate method by HPLC-UV to quantify meloxicam (MLX) in human plasma and its application to comparative bioavailability study between MLX formulation and manipulated meloxicam + prednisone + cyclobenzaprine + diacerein + hidroxychloroquine is described. MLX and the internal standard (piroxicam) were extracted from plasma using protein precipitation. Chromatographic separation of meloxicam, piroxicam, other active ingredients, diacerein metabolite (Rhein) and plasma interferents was achieved with a C18 column, using a mobile phase of 20 mM sodium Hydrogen pH 3.0 and acetonitrile, with detection at 360 nm and retention times of 4.7, 3.7 and 4.1 min, respectively. The method was linear over the concentration range of 50 to 3000 ng/mL, meloxicam and piroxicam had an average recovery from plasma of 96 and 97 %, respectively. The precision and accuracy (intra-, inter-day) were less than 6 %. The method was successfully applied to a pilot pharmacokinetic study.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Seroprevalence and risk factors associated with Helicobacter pylori infection in blood donors in Salvador, Northeast-Brazil

Helicobacter pylori plays an important role in the etiology of peptic ulcer disease. Its prevalence appears to be higher in developing countries. We evaluated the seroprevalence of H. pylori and risk factors associated with infection in voluntary blood donors who attended the main blood center of the city of Salvador, Brazil. The subjects responded to an epidemiological questionnaire, with information about sex, age, race, lifestyle, social-economic level indicators, and residence and hygiene conditions. Anti-H. pylori antibody was determined by ELISA (Cobas Core, Roche). Three hundred and seven subjects were included in the study. Anti-H. pylori antibody results were indeterminate in 33 individuals (10.8%), who were excluded from analysis. Among the remaining 274 subjects, 187 (68.2%) were anti-H. pylori positive. Based on multivariate logistic regression analysis three variables were found to be significantly associated with a higher prevalence of H. pylori infection: absence of plumbing in the residence during childhood, a history of rainwater invading the dwelling during childhood, and low ingestion of milk.339345Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Citotoxicity and immune response induced by organopalladium(II) compounds in mice bearing Ehrlich ascites tumour

Cyclometallated palladium(II) complexes are reactive inorganic compounds employed in several biological studies because of their antitumour potential and interaction with immune system. In the present study, the immune and citotoxic response induced by two organopalladated complexes: [{Pd(N,C-dmba)} 2(μ-NCS) 2] (1), [Pd(C-dmba)(NCS)(dppp)] (2) [dmba = N,N′-dimethylbenzylamine, dppp = 1,3-bis(diphenylphosphino)propane] and cisplatin (cis-DDP), as standard, were investigated in mice bearing Ehrlich ascites tumour. The mice were divided into five groups and inoculated with the compounds (1) or (2) or cisplatin, or only vehicle or phosphate-buffered saline (PBS). Many parameters were evaluated, such as tumour cell percentage in the peritoneal exsudate, levels of seric nitric oxide (NO) and tumour necrosis factor-alpha (TNF-α) and increase in life span. Analysis of all data revealed, for compound (2), an activity similar to that presented by cisplatin, resulting in increased life span, lower levels of seric TNF-α and increase in NO production. ©2007 Sociedade Brasileira de Química