Growth of populations and the fungus garden of Atta sexdens rubropilosa (Hymenoptera, Formicidae) response to foraged substrates

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

Nest Digging by Leaf-Cutting Ants: Effect of Group Size and Functional Structures.

Leaf-cutting ant workers dig underground chambers, for housing their symbiotic fungus, interconnected by a vast quantity of tunnels whose function is to permit the entrance of food (leaves), gaseous exchanges, andmovement of workers, offspring, and the queen. Digging is a task executed by a group of workers, but little is known about the group effect and group-constructed functional structures. Thus, we analyzed the structures formed by worker groups (5, 10, 20, and 40 individuals) of the leaf-cutting ant, Atta sexdens rubropilosa, for 2 days of excavation. The digging arena was the same for the 4 groups, with each group corresponding to a different density. Our results verified a pattern of tunneling by the workers, but no chamber was constructed. The group effect is well known, since the 40-worker group dug significantly more than the groups of 5, 10, and 20. These groups did not differ statistically from each other. Analysis of load/worker verified that workers of the smallest group carried the greatest load. Our paper demonstrates the group effect on the digging of nests, namely, that excavation is proportional to group size, but without emergence of a functional structure such as a chamber.

A lectin from the lichenized Basidiomycete Dictyonema glabratum

A lectin with hemagglutinating activity has been isolated from an aqueous extract of the symbiotic phenotype of Dictyonema glabratum and its cyanobacterial photobiont Scytonema sp. The purified lectin had a pi of 6.8 and its molecular mass was investigated by electrospray ionization mass spectrometry, gel filtration and SDS-PAGE, which indicated its native conformation as a dimer formed by two identical subunits of 16540 Da. The lectin is a glycoprotein with a low degree of glycosylation, containing galactose, xylose, glucose and mannose as neutral monosaccharides, in addition to glucosamine, which could indicate both N- and O-linkages. Amino acid analysis showed the predominance of nonpolar residues such as phenylalanine. Agglutination of human erythrocytes required divalent cations, which is affected by addition of EDTA. The lectin was more stable at 30 degreesC or less for at least 1 h and between pH 5.0 and 7.0. Among the various compounds tested for hemagglutination inhibition, N-acetylgalactosamine was the most active. The potential role of this lectin in recognition of the compatible cyanobacterial photobiont is discussed.

A potential synbiotic product improves the lipid profile of diabetic rats

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

A report of 49 cases of cnidarian envenoming from southeastern Brazilian coastal waters

Forty-nine accidents caused by jellyfish (Cnidaria) were observed during a period of 5 years on the southeastern coast of Brazil. Most of them involved male patients (65.3%), the injured areas being mainly the legs (71.3%) and the trunk (65.3%). Twenty accidents with Chiropsalmus quadrumanus, four with Physalia physalis and 20 with unidentified jellyfish presented intense pain, linear plaques and systemic symptoms. The five cases with Olindias sambaquiensis caused mild pain, round plaques and no systemic symptoms. There are a few reports on accidents caused by jellyfish, in this country, and scarce clinical or epidemiological data are available up to the present moment. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Tropical dermatology: Marine and aquatic dermatology

Dermatoses caused by marine organisms are frequently seen in dermatology clinics worldwide. Cutaneous injuries after exposure to marine environments include bacterial and fungal infections and lesions caused by aquatic plants and protists. Some of these diseases are well known by dermatologists, such as Vibrio vulnificus septicemia and erysipeloid, but others are uncommon, such as envenomation caused by ingestion or contact with certain dinoflagellates or cyanobacteria, which are associated with rashes that can begin Within minutes after exposure. Many marine/aquatic invertebrates, such as sponges, cnidarians, echinoderms, crustaceans, and mollusks, are associated with different kinds of dermatologic lesions that call vary from irritant or allergic contact dermatitis to physical trauma and envenomations. These cutaneous lesions May result in mild local reactions or can be associated with severe systemic reactions. Invertebrate animals, such as cnidarians, sea urchins, and worms, and aquatic vertebrates, such as venomous fishes and stingrays, are commonly associated with skin lesions in many countries, where they call constitute occupational dermatoses among fishermen and scuba divers, but they can also be observed among persons who contact these animals in kitchens or beaches. The presence of unusual lesions, a recent travel history, and/or a report of contact with an aquatic environment (including ownership of a marine or freshwater aquarium) should alert the dermatologist to the etiology of the cutaneous problems. (J Am Acad Dermatol 2009;61:733-50.)

Enzima e simbiótico para frangos criados nos sistemas convencional e alternativo

O objetivo deste trabalho foi estudar os efeitos da inclusão de enzima e simbiótico nas rações de frangos de corte criados nos sistemas convencional e alternativo sobre o desempenho, rendimento de carcaça, cortes e gordura abdominal e também avaliar economicamente o uso destes aditivos em ambos os sistemas de criação. Foram utilizados 720 pintos machos Cobb, com um dia de idade, distribuídos em um delineamento em blocos casualizados no esquema fatorial 2x3, com dois sistemas de criação: convencional (com promotor de crescimento) e alternativo (sem promotor de crescimento) e três aditivos: sem outro aditivo (SA), com simbiótico (SI) e com enzima + simbiótico (SIE), com 4 repetições de 30 aves cada. Aos 42 dias de idade, o fator de produção (FP) foi menor (P<0,05) para aves SA (324), quando comparadas às tratadas com SI (334) e SIE (337). Aves criadas no sistema convencional apresentaram maior (P<0,05) FP (338), quando comparadas às do sistema de criação alternativo (325). No sistema alternativo, a conversão alimentar foi melhor (P<0,05) para aves SI (1,77), quando comparadas às SIE (1,82) e SA (1,85). O uso de SI e SIE favorece o desempenho dos frangos aos 42 dias de idade e não influencia o rendimento de carcaça, cortes e gordura abdominal, tanto no sistema convencional como no alternativo, sendo que estes aditivos aumentam os custos de produção em ambos os sistemas. O sistema alternativo de criação proporciona maior retorno econômico, apesar do menor fator de produção.

Major developments in conulariid research: problems of interpretation and future perspectives

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

Cladistic analysis of the suborder Conulariina Miller and Gurley, 1896 (Cnidaria, Scyphozoa; Vendian-Triassic)

Results of a cladistic analysis of the suborder Conulariina Miller and Gurley, 1896, a major extinct (Vendian-Triassic) group of scyphozoan cnidarians, are presented. The analysis sought to test whether the three conulariid subfamilies (Conulariinae Walcott, 1886, Paraconulariinae Sinclair, 1952 and Ctenoconulariinae Sinclair, 1952) recognized in the Treatise on Invertebrate Paleontology ( TIP) are monophyletic. A total of 17 morphological characters were scored for 16 ingroup taxa, namely the genera Archaeoconularia, Baccaconularia, Climacoconus, Conularia, Conulariella, Conularina, Ctenoconularia, Eoconularia, Glyptoconularia, Metaconularia, Notoconularia, Paraconularia, Pseudoconularia, Reticulaconularia, Teresconularia and Vendoconularia. The extant medusozoan taxa Cubozoa, Stauromedusae, Coronatae and Semaeostomeae served as outgroups. Unweighted analysisof the data matrix yielded 1057 trees, and successive weighting analysis resulted in one of the 1057 original trees. The ingroup is monophyletic with two autapomorphies: (1) the quadrate geometry of the oral region; and (2) the presence of a mineralized (phosphatic) periderm. Within the ingroup, the clade (Vendoconularia, Teresconularia, Conularina, Eoconularia) is supported by the sinusoidal longitudinal geometry of the transverse ridges, and the much larger clade (Baccaconularia, Glyptoconularia, Metaconularia, Pseudoconularia, Conularia, Ctenoconularia, Archaeoconularia, Notoconularia, Climacoconus, Paraconularia, Reticulaconularia) is supported by the presence of external tubercles, which, however, were lost in the clade (Notoconularia, Climacoconus, Paraconularia, Reticulaconularia). As proposed by Van Iten et al. (2000), the clade (Notoconularia, Climacoconus, Paraconularia, Reticulaconularia) is supported by the termination and alternation of the transverse ribs in the corner sulcus. The previously recognized subfamilies Conulariinae, Paraconulariinae and Ctenoconulariinae were not recovered from this analysis. The diagnostic features of Conulariinae (continuation of the transverse ornament across the corner sulcus and lack of carinae) and Ctenoconulariinae ( presence of carinae) are symplesiomorphic or homoplastic, and Paraconulariinae is polyphyletic. The families Conulariellidae Kiderlen, 1937 and Conulariopsidae Sugiyama, 1942, also recognized in the TIP, are monogeneric, and since they provide no additional phylogenetic information, should be abandoned.

Survival of Atta sexdens workers on different food sources

Leaf-cutting ants belonging to the tribe Attini are major herbivores and important agriculture pests in the neotropics, these ants being thought to feed on the sap which exudes from the plant material which they cut and also on the mycelium of a symbiotic fungus that grows on plant material inside their nests in what is called 'the fungus garden'. However, we have found that the survival of Atta sexdens worker ants on leaves, on mycelium. of the ants' symbiotic fungus, Leucoagaricus gongylophorus, or on plant polysaccharides was the same as that of starved A. sexdens, while, conversely, significantly longer survival was achieved by ants fed on the fungus garden material or on some of the products (especially glucose) of the hydrolysis of plant polysaccharides. We found that the fungus garden contained glucose at a higher concentration than that found in leaves or fungal mycelium, and that this glucose was consumed by the ant to the extent that it was probably responsible for up to 50% of the nutritional needs of the workers. The fungus garden contained polysaccharide degrading enzymes (pectinase, amylase, xylanase and cellulase) in proportions similar to that observed in laboratory cultures of L. gongylophorus. It thus appears that A. sexdens workers obtain a significant part of their nutrients from plant polysaccharide hydrolysis products produced by the action of extracellular enzymes released by L. gongylophorus. In this paper we discuss the symbiotic nutrition strategy of A. sexdens workers and brood and the role played by plant polysaccharides in the nutrition of attine ants. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

Yeasts and filamentous fungi carried by the gynes of leaf-cutting ants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Filamentous fungi found in Atta sexdens rubropilosa colonies after treatment with different toxic bait formulations

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Monoculture of Leafcutter Ant Gardens

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nodulação e micorrização em Anadenanthera peregrina var. falcata em solo de cerrado autoclavado e não autoclavado

Anadenanthera peregrina var. falcata (angico-do-cerrado), uma leguminosa arbórea, forma associações simbióticas com bactérias fixadoras de nitrogênio (rizóbios) e com fungos micorrízicos arbusculares. Com o objetivo de avaliar a eficiência da inoculação de fungos micorrízicos e rizóbios no crescimento inicial de plantas de angico-do-cerrado, crescidas em solo autoclavado e em solo não autoclavado com e sem inoculação, foi desenvolvido um experimento em casa de vegetação, utilizando raízes micorrizadas de milho e uma mistura de isolados de rizóbios como inoculantes. O crescimento das plantas foi influenciado positivamente pela concomitante inoculação do fungo micorrízico e do rizóbio, tendo as plantas desse tratamento apresentado biomassa cerca de 60 % maior do que o controle no décimo mês. A inoculação de apenas um dos microssimbiontes, entretanto, não provocou diferença na produção de biomassa das plantas. A percentagem de colonização micorrízica foi significativamente mais alta e o número de nódulos maior nas raízes das plantas crescidas no solo não autoclavado, ocasionados pela população de fungos e rizóbios nativos. Nesse tratamento, houve pequeno acúmulo de matéria no xilopódio, provavelmente em virtude do dreno fotossintético por parte dos microssimbiontes, e a concentração de P na parte aérea e xilopódio dessas plantas foi cerca de 1,2 e 8 vezes maior, respectivamente, por causa da colonização micorrízica.

Effective potential of two coupled binary matter wave bright solitons with spatially modulated nonlinearity

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