ANTS AS POTENTIAL VECTORS OF PATHOGENS IN HOSPITALS IN THE STATE OF SAO-PAULO, BRAZIL

Baiting studies performed in large, medium and small hospitals in Brazil revealed the presence of 14 ant species, with up to nine recorded in one hospital. Dominant species were exotic ants, and in the large hospital, Tapinoma melanocephalum was the most prevalent. Ants were not uniformly spread through the hospitals, but tended to be found in the more critical areas, particularly in nursery, intensive care, obstetrics, neurology and dermatology units. Bacteriological studies using specific media for bacteria associated with intra-hospital infections indicated the potential for the mechanical vectoring of species of Staphylococcus, Serratia, Klebsiella, Acinetobacter, Enterobacter, Candida and Enterococcus by ants. Although T. melanocephalum did not have the highest rate of association with these bacteria, its ubiquitous occurrences resulted in the highest overall potential as a vector of these bacteria. Because of a large number of ant species occurring in Brazilian hospitals, ants pose a potential problem to the spread of diseases in hospitals. Because of the number of associated ant species in hospitals, the control of this potential problem is much more difficult than in registered temperate areas.

Toxic effects of leaves of Ricinus communis (Euphorbiaceae) to laboratory nests of Atta sexdens rubropilosa (Hymenoptera: Formicidae)

Laboratory nests of the leaf-cutting ant Atta sexdens rubropilosa Forel fed daily with leaves of Ricinus communis showed a gradual decrease in fungal garden volume, a higher ant mortality rate, and fungal garden extinction after 6 weeks. The mean oxygen consumption rate of these ants was higher than that of control ants collected from nests fed with leaves of Eucalyptus alba (Myrtaceae) suggesting one or more components of the leaves of R. communis had a direct physiological effect on the ants, in addition to inhibiting fungal garden growth.

Histochemical and ultrastructural cytochemistry of glycogen in ovarioles of Neoponera villosa ants (hymenoptera : ponerinae)

In Neoponera villosa ants, we found ovaries of the polytrophic meroistic type which is characterized by the presence of nurse cells forming together with the oocyte, the so-called follicles. The nurse cells have the primary function of supplying the oocyte with RNA, but they contribute to the supply of other elements such as glycogen. With the objetive of detecting the presence of this substance in the ovarioles of workers and queens of N. viillosa ants the ovaries were removed and processed according to electron microscopy technic for glycogen detection. Glycogen is a common element in insect oocytes and is abundantly distributed in the cytoplasm of N. villosa workers and queens. However, in ovarian follicles it can only be detected at stages II and III of development. Glycogen synthesis probably occurs predominantly in nurse cells which transfer it into the oocyte through the nourish pore. This process requires high energy expenditure that justify the large numbers of mitochondria associated with glycogen in the nurse cell cytoplasm. The amount of glycogen in the nurse cells of queens is slightly greater than workers.

Ecological interaction between Atta sexdens (Hymenoptera: Formicidae) and the vegetation of a mesophyll semideciduous forest fragment in Botucatu, SP, Brazil

Among 89 plants species growing in a subtropical dry forest fragment located in Botucatu, State of São Paulo, Brazil, 35 species were cut by Atta sexdens, representing 39.34% of the current plants existing in this area. A. sexdens L., 1758 (Hymenoptera: Formicidae) has a selective preference for the following species: Alchornea triplinervia, Faramea cyanea, Cariniana estrellensis and Casearea obliqua, with the first being the most cut species. The frequency and absolute densities of the plant families and species significantly influence the selection process. When comparing the absolute frequency regarding the 10 most cut plant species and the cutting frequency, significant data were obtained only for the euphorbiaceous A. triplinervia species, proving the preference of A. sexdens for this species in particular. These interactions are discussed based on ecological and management factors in agro-ecosystems.

Toxicity of Cedrela fissilis to Atta sexdens rubropilosa (Hymenoptera: Formicidae) and its symbiotic fungus

Crude extracts from roots, stems, branches, fruits and leaves of Cedrela fissilis were tested to verify their toxicity to Atta sexdens rubropilosa workers and to their symbiotic fungus Leucoagaricus gongylophorus. The workers that were fed daily on an artificial diet to which crude extracts from this plant were added had a higher mortality rate than the controls, especially for the hexane, dichloromethane and methanol crude extracts from roots (RH, RD and RM) and from leaves (LH, LD and LM). Fungal growth was inhibited by the hexane (RH) and dichloromethane crude extract from roots (RD). The RH, RD and FD crude extracts were fractioned and their fractions were tested. All the fractions tested presented toxicity to the ants and some fractions (RH-H, RH-D, RD-4 and RD-5) completely inhibited fungus development. The possibility of controlling these insects in the future using Cedrela fissilis compounds that can simultaneously target both organisms is discussed.

Morphometry of the sexual forms of Acromyrmex subterraneus brunneus Forel, 1911 (Hym., Formicidae) in queenright and queenless laboratory colonies

A morphometric study was performed on the sexual forms of Acromyrmex subterraneus brunneus in colonies kept under laboratory conditions. The males studied were obtained from queenright and queenless colonies, i.e. they were produced by either the queen or the workers. Cluster analysis revealed a wide distribution in the size of the sexual forms produced in queenless colonies compared with queenright colonies, and that some of the worker-produced males were significantly smaller than those produced in queenright colonies. However, we found no indication that the males produced in queenless colonies are unable to mate, as smaller and larger males had identical genitalia that varied only in size, and therefore probably represent an alternative route of reproduction in this species. © 2005 Blackwell Verlag.

Electrophysiological responses of Atta sexdens rubropilosa workers to essential oils of Eucalyptus and its chemical composition

The leaf-cutting ant Atta sexdens rubropilosa Forel, 1908 is the most harmful of the Eucalyptus pests, causing severe losses in wood production through defoliation. Various strategies have been tried and effort spent on the development of methods to control this pest, however no practical and environmentally acceptable one currently exists. In this work the chemical composition of the essential oil of seven Eucalyptus species was identified and the selectivity and sensitivity of antennal receptors of A. sexdens rubropilosa workers to the volatile compounds were determined using the electroantennographic technique (EAG and GC-EAD). Analysis by GC-EAD showed in E. cloesiana and E. maculata, respectively, seventeen and sixteen terpenes that elicited responses in ant workers' antennae, indicating the potential role of the essential oils as allelochemicals that determine the choice of the foraging material. © 2006 Verlag der Zeitschrift für Naturforschung.

Measuring and analyzing color and texture information in anatomical leaf cross sections: An approach using computer vision to aid plant species identification

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The usable leftover one-dimensional cutting stock problem-a priority-in-use heuristic

We consider a one-dimensional cutting stock problem in which the material not used in the cutting patterns, if large enough, is kept for use in the future. Moreover, it is assumed that leftovers should not remain in stock for a long time, hence, such leftovers have priority-in-use compared to standard objects (objects bought by the industry) in stock. A heuristic procedure is proposed for this problem, and its performance is analyzed by solving randomly generated dynamic instances where successive problems are solved in a time horizon. For each period, new demands arise and a new problem is solved on the basis of the information about the stock of the previous periods (remaining standard objects in the stock) and usable leftovers generated during those previous periods. The computational experiments show that the solutions presented by the proposed heuristic are better than the solutions obtained by other heuristics from the literature. © 2012 The Authors. International Transactions in Operational Research © 2012 International Federation of Operational Research Societies.

Influência do ambiente no desenvolvimento de colônias iniciais de formigas cortadeiras (Atta sexdens rubropilosa)

Annually, mature colonies of Atta ants produce winged males and females, where leave the colony in which they were produced to form new colonies and thus continue the species perpetuation. The foundation of Atta spp. colonies always involves high queen effort, solely responsible for growing the fungus and the care with itself and its offspring. During the foundation there is consumption of body reserves. This study investigated how the environment influences the development of newly founded colonies of leaf cutting ant, Atta sexdens rubropilosa. Therefore, it was compared field colonies collected five months after the nuptial flight and colonies maintained in the laboratory since the nuptial flight. It was analyzed the weight and size of the population (number of workers, larvae, pupae and eggs), the workers size, the volume and weight of the fungus garden and queen effort for the nest foundation (lipid content and weight of queens). In comparison to the field colonies, the laboratory colonies showed higher values in the weight and size of population, the volume and weight of the fungus garden. Measures of workers by class size did not vary between colonies from field and laboratory. The queen effort for nest foundation was higher in field colonies, which showed a lower percentage of fat and lower weight compared to laboratory colonies. These results show that the environment has a strong influence on the colonies development during the foundation, as well as on the physiological status of the queens, and therefore the survival, development and success of the colony, it is a reflection of the queen efforts and of the environment conditions.

Comportamento de cuidado da prole da saúva-limão Atta sexdens rubropilosa Forel, 1908 (Hymenoptera, formicidae)

Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

Leveduras isoladas de ninhos de formigas da tribo Attini (Hymeniptera: Formicidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nutrients distribution in diseased coffee leaf tissue

Knowing the structure and distribution of nutrients in plant tissues can clarify some mechanisms of pathogen attack in plants and plant defense against infection, thus helping management strategies. The aim of this study was verify differences in distribution of mineral nutrients in coffee leaf tissues around foliar lesions of bacterial blight of coffee, blister spot, cercospora leaf, phoma leaf spot and coffee leaf rust. Fragments of leaf tissue surrounding the lesions were dehydrated in silica gel, carbon covered and subjected to X-ray microanalysis (MAX). Thirty-three chemical elements were detected in leaf tissue; however, there was variation in potassium and calcium contents surrounding the lesions. The highest potassium content was found in asymptomatic tissues surrounding the lesions, decreasing toward the transition zone and reaching minimum content in symptomatic tissues. The highest calcium content was found in symptomatic tissues, decreasing toward the transition zone and reaching minimum content in asymptomatic tissues. Therefore, MAX can be used to analyze the composition and distribution of nutrients in plant tissues and, if associated with mineral nutrition, it may help understand host-pathogen relationships and plant disease management.

Extrato metanólico de folhas de mandioca como alternativa ao controle da lagarta-do-cartucho e de formigas cortadeiras

The objective of this study was to characterize phenolic compounds and evaluate the effect, under laboratory conditions, of the cassava leaf powder methanol extract on the development of fall armyworm Spodoptera frugiperda and of leaf-cutting ant Atta sexdens rubropilosa. The extract was incorporated into an artificial diet, to which the armyworm was exposed, at concentrations of 250, 500, 1000 and 1500 mg kg-1,in order to evaluate biological characteristics. Soon after the insects emergence, another experiment was conducted to verify the possible sub lethal activity of the extract; therefore, S. frugiperda couples were isolated in cages and eggs were collected and counted. The Manihot esculenta Crantz extract caused a reduction in the percentage of armyworm survival, as well as in the eggs number. Then, the same extract was solubilized in 10% ethanol and applied to ants; mortality was observed, compared to the control. It is possible to conclude that the M. esculenta Crantz leaf powder methanolic extract, containing gallic acid and catechin, is a promising alternative to control S. frugiperda and Atta sexdens rubropilosa.

Leveduras isoladas de ninhos de Acromyrmex Balzani (Hymenoptera: Formicidade) de áreas de cerrado do Estado do Tocantins

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)