Effect of light intensity on methylxanthine contents of Ilex paraguariensis A. St. Hil.

Maté (Ilex paraguariensis A. St. Hil.) is a shade-tolerant species, frequently cultivated on agroforestry systems or even in monoculture. Secondary metabolism of maté includes the methylxanthines, caffeine and theobromine. Shading could alter the quantitative profile of these compounds in the plant, and since the secondary chemistry of maté is decisive to determine the quality of raw material, the caffeine and theobromine content under different light intensities were investigated. Artificial shading obtained by a nylon screen and natural shading produced by other trees were tested. Methylxanthines content was increased with the reduction of light, but only in the low light intensity treatment. A negative correlation was found between biomass accumulation and methylxanthines content. But the total methylxanthines yield per plant was not altered.     

Microbiological and immunological features of oral candidiasis

Candida albicans(C. albicans) is the major infectious agent of oral candidiasis, and both innate immunity and cell-mediated immune response participate in the control of the fungal infections. The aim of this study was to correlate the clinical forms of oral candidiasis with the number of colony forming units (CFU) of C. albicans in saliva and to characterize T cell response in patients with oral candidiasis. Participants included 75 subjects: 36 with lesions of candidiasis and 39 without lesions of oral candidiasis. A 2-ml sample of saliva was collected from all subjects for microbiological analysis. Cytokine levels were determined by ELISA in supernatants of peripheral blood mononuclear cells of 25 patients with oral candidiasis, after in vitro stimulation with C. albicans antigens. In 48% of patients, no association was observed with denture use. C. albicans was detected in the saliva of 91.7% of patients with oral candidiasis, and there was an association between the number of CFU and the presence of oral lesions. A type Th1 immune response was observed in supernatants of peripheral blood mononuclear cells stimulated with C. albicans antigens. In contrast, IL-5 and IL-10 levels were very low or undetectable. Together, this study shows an association between clinical forms of oral candidiasis and the number of colonies of C. albicans in saliva, and that a systemic immune response characterized by the production of TNF-alpha and IFN-gamma is observed in patients with oral candidiasis.     

Effects of temperature, storage period and the number of individuals on the detection of the false spider mite Cardinium endosymbiont

Cardinium have been found as endosymbionts of Brevipalpus phoenicis, the mite vector of the Citrus leprosis virus. With the long-term objective being to understand the mechanisms of plant-virus-vector interactions, we evaluated the different storage conditions and periods, as well as the number of mites needed for PCR-amplification of such endosymbionts, making it possible to collect mites in different geographical regions without prolonged storage compromising subsequent analyses.     

Contribution of anaerobic metabolism to reactive hyperemia in skeletal muscle

Elevated blood flow (reactive hyperemia) is seen in many organs after a period of blood flow stoppage. This hyperemia is often considered to be due in part to a shift to anaerobic metabolism during tissue hypoxia. The aim of our study was to test this hypothesis in skeletal muscle. For this purpose we measured NADH fluorescence at localized tissue areas in cat sartorius muscle during and after arterial occlusions of 5-300 s. In parallel studies, red blood cell (RBC) velocity was measured in venules. Tissue NADH fluorescence rose significantly with occlusions of 45 s or greater, reaching a maximum of 44% above control at 180 s. Peak RBC velocity rose to four times control as occlusion duration was increased from 5 to 45 s, but hyperemia duration was stable at approximately 70 s. With occlusions of 45-240 s, hyperemia duration increased progressively to 210 s while peak flow was unchanged. However, after 300-s occlusions, peak flow rose to six times above control and hyperemia duration fell to 140 s. With occlusions of 45-300 s the time integral both of increased NADH fluorescence and of reduced fluorescence following occlusion release showed a high degree of correlation with the additional hyperemia. We conclude that in this muscle anaerobic vasodilator metabolites are responsible for the increase in reactive hyperemia with arterial occlusions longer than 45 s. Since the durations of reactive hyperemia and reduced fluorescence are substantially different, vasodilator metabolite removal may be due to washout by the bloodstream rather than metabolic uptake.     

Characterisation of fungal lanostane-type triterpene acids by electrospray ionisation mass spectrometry

Lanostane-triterpene acids obtained from the culture of the fungus Coriolellus malicola were studied by electrospray mass spectrometry in the negative ion mode using quadrupole time-of-flight and quadrupole ion trap analysers. Despite the differences observed in the mass spectra recorded with these instruments, a set of fragment ions was found to be characteristic of the family, depending on the Delta(7,9(11)) or Delta(8) skeleton and the particular functional group at C-3.     

Cell cycle kinases in cancer

Cell division in mammalian cells is driven by protein kinases that regulate progression through the various phases of the cell cycle. Cyclin-dependent kinases (Cdks) regulate cell cycle commitment, DNA synthesis and the onset of mitosis. Kinases of the Aurora, Polo and Nek families participate in the centrosome cycle and modulate spindle function. Additional kinases such as Bub1, BubR1 and Mps1 regulate the spindle assembly checkpoint. It has been well established that misregulation of Cdks is one of the most frequent alterations in human cancer. Recent evidence indicates that mutations involving mitotic kinases are also linked to tumor development. These findings suggest novel strategies to use cell cycle kinases as targets for therapeutic intervention.     

Mammal survey at a ranch of the Brazilian Cerrado

The wildlife of the Brazilian Cerrado is threatened by large-scale habitat loss, in particular due to conversion to agricultural land. It is essential to study how the mammal fauna copes with the highly fragmented, human-influenced, non-protected landscape. The paper presents the results of a survey of the large to medium-sized mammals of a typical cattle ranch with a mixture of human-created and natural vegetation types. We recorded 18 species. Surprisingly, several species were found to still thrive in the area, however, many species are rare or have become extinct. We conclude the paper with comments relevant for the conservation of mammals in the Cerrado as a whole.     

Surveying carnivores at large spatial scales: a comparison of four broad-applied methods

Reliable methods to estimate species richness are very important to managers and conservationists because they provide key data to make the right decisions in conservation programmes. In the case of carnivore mammals, traditional methods, such as direct count censuses, are not useful since these animals are usually scarce, elusive and nocturnal. Difficulties in carnivore sampling are compounded when monitoring programmes are developed at large spatial scales, where high economic costs and field efforts are necessary to achieve reliable richness or abundance estimates. These problems have highlighted the need to find more effective carnivore survey methods, especially in regions with high rates of landscape change, such as the Mediterranean basin. The present study, performed in a typical Mediterranean area, was the first in Europe to test simultaneously the relative efficiencies of four broad-applied sampling methods to detect carnivore species at large spatial scales. Sign surveys based on scat detection, scent stations, camera-trapping and live-trapping were investigated. We compared efficiencies using biological parameters and by considering both the logistic and economic costs of each method. Overall, scent stations and sign surveys were the most efficient methods both in economic and logistic terms. In addition, the use of scent stations may be necessary to detect species rarely detected by scats. Detailed and extensive training programmes for conducting sign surveys and scent stations may overcome perceived problems thus enhancing the widespread use of both methods. Our results are applicable not only to other Mediterranean areas, but also to other habitats and regions of the world. More research into the suitability of these and other methods in relation to different landscapes, seasons and species is required.     

Mating type and the genetic basis of self-fertility in the model fungus Aspergillus nidulans

Sexual reproduction occurs in two fundamentally different ways: by outcrossing, in which two distinct partners contribute nuclei, or by self-fertilization (selfing), in which both nuclei are derived from the same individual. Selfing is common in flowering plants, fungi, and some animal taxa. We investigated the genetic basis of selfing in the homothallic fungus Aspergillus nidulans. We demonstrate that alpha and high-mobility group domain mating-type (MAT) genes, found in outcrossing species, are both present in the genome of A. nidulans and that their expression is required for normal sexual development and ascospore production. Balanced overexpression of MAT genes suppressed vegetative growth and stimulated sexual differentiation under conditions unfavorable for sex. Sexual reproduction was correlated with significantly increased expression of MAT genes and key genes of a pheromone-response MAP-kinase signaling pathway involved in heterothallic outcrossing. Mutation of a component MAP-kinase mpkB gene resulted in sterility. These results indicate that selfing in A. nidulans involves activation of the same mating pathways characteristic of sex in outcrossing species, i.e., self-fertilization does not bypass requirements for outcrossing sex but instead requires activation of these pathways within a single individual. However, unlike heterothallic species, aspects of pheromone signaling appeared to be independent of MAT control.