RESUMO
AIM: To screen and identify a potential biosurfactant-producing yeast strain isolated from Antarctic soil and to evaluate the fermentation process kinetics of the most promising strain on biosurfactant production using glycerol as carbon source. METHODS AND RESULTS: From the 68 isolated yeast strains, 11 strains were able to produce biosurfactants after Emulsification Index (E.I.) and Drop Collapse tests, reaching an E.I. higher than 10%. Strain 1_4.0 was the best producer, identified as Candida glaebosa based on molecular analysis. Yeast was cultivated in a medium composed of glycerol supplemented with yeast extract for 120 h to determine the process kinetics. The increased C/N ratio affected yeast growth and biosurfactant production. Biosurfactant release was associated with the end of exponential and beginning of the stationary growth phases. Results indicated an E.I. of 30% at the end of the fermentation. CONCLUSIONS: The feasiability of C. glaebosa to produce biosurfactant from a low-cost medium cultivation shows a great impact on the development of bioresource in the Antarctica terrestrial environment. SIGNIFICANCE AND IMPACT OF THE STUDY: Although the diversity of psychrophilic/psychrotolerant micro-organisms from Antarctica has been the preferred subject of study by microbiologists, terrestrial microfungal communities are scarcely investigated and literature about the biotechnological potential of such micro-organisms should cover important biomolecules in addition to cold-adapted enzymes. In the present study, for the first time, the Maritime Antarctica environment was screened as a novel source of biosurfactants produced by micro-organisms.
Assuntos
Candida/metabolismo , Microbiologia do Solo , Tensoativos/metabolismo , Regiões Antárticas , Candida/isolamento & purificação , Glicerol/metabolismo , Ilhas , Cinética , Tensoativos/isolamento & purificação , Leveduras/crescimento & desenvolvimento , Leveduras/isolamento & purificação , Leveduras/metabolismoRESUMO
The relationship of attine ants with their mutualistic fungus and other microorganisms has been studied during the last two centuries. However, previous studies about the diversity of fungi in the ants' microenvironment are based mostly on culture-dependent approaches, lacking a broad characterization of the fungal ant-associated community. Here, we analysed the fungal diversity found on the integument of Atta capiguara and Atta laevigata alate ants using 454 pyrosequencing. We obtained 35,453 ITS reads grouped into 99 molecular operational taxonomic units (MOTUs). Data analysis revealed that A. capiguara drones had the highest diversity of MOTUs. Besides the occurrence of several uncultured fungi, the mycobiota analysis revealed that the most abundant taxa were the Cladosporium-complex, Cryptococcus laurentii and Epicoccum sp. Taxa in the genus Cladosporium were predominant in all samples, comprising 67.9 % of all reads. The remarkable presence of the genus Cladosporium on the integument of leaf-cutting ants alates from distinct ant species suggests that this fungus is favored in this microenvironment.
Assuntos
Formigas/microbiologia , Cladosporium/isolamento & purificação , Animais , Biodiversidade , Brasil , Cladosporium/classificação , Cladosporium/genética , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Tegumento Comum/microbiologia , Micobioma , Prevalência , Análise de Sequência de DNA , Pele/microbiologia , SimbioseRESUMO
Fungus-growing ants of the genus Atta are known for their leaf-cutting habit, a lifestyle they have maintained since their 50-million-year-old co-evolution with a mutualistic fungus, cultivated as food. Recent studies have highlighted that, in addition to the mutualistic fungus, nests of ants harbor a great diversity of microbial communities. Such microorganisms include the dematiaceous fungi, which are characterized by their melanized cell walls. In order to contribute to the knowledge of fungal ecology, as well as opportunistic strains that may be dispersed by these social insects, we isolated and identified fungi carried by gynes of Atta capiguara and Atta laevigata, collected from colonies located in Fazenda Santana, Botucatu (São Paulo, Brazil). The isolation was carried out using the oil flotation technique, which is suitable for the growth of black fungi. Inoculated plates were incubated at 25 and 35 °C until black cultures were visible (20-45 days). Isolates were identified based on microscopic and molecular characteristics. Some isolated genera were: Cladophialophora, Cladosporium, Exophiala, Ochroconis, Phaeococcomyces, Phialophora and Penidiella. Hyaline species were also found. The results obtained from this work showed that leaf-cutting gynes may contribute to the dispersal of opportunistic dematiaceous fungi. It is suggested that more attention should be paid to this still unexplored subject.
Assuntos
Formigas/microbiologia , Biodiversidade , Fungos/classificação , Fungos/isolamento & purificação , Animais , Brasil , Humanos , Técnicas Microbiológicas , Infecções Oportunistas/microbiologia , TemperaturaRESUMO
The aim of the present study was to investigate the taxonomic identity of yeasts isolated from the Antarctic continent and to evaluate their ability to produce enzymes (lipase, protease and xylanase) at low and moderate temperatures. A total of 97 yeast strains were recovered from marine and terrestrial samples collected in the Antarctica. The highest amount of yeast strains was obtained from marine sediments, followed by lichens, ornithogenic soils, sea stars, Salpa sp., algae, sea urchin, sea squirt, stone with lichens, Nacella concinna, sea sponge, sea isopod and sea snail. Data from polyphasic taxonomy revealed the presence of 21 yeast species, distributed in the phylum Ascomycota (n = 8) and Basidiomycota (n = 13). Representatives of encapsulated yeasts, belonging to genera Rhodotorula and Cryptococcus were recovered from 7 different Antarctic samples. Moreover, Candida glaebosa, Cryptococcus victoriae, Meyerozyma (Pichia) guilliermondii, Rhodotorula mucilaginosa and R. laryngis were the most abundant yeast species recovered. This is the first report of the occurrence of some species of yeasts recovered from Antarctic marine invertebrates. Additionally, results from enzymes production at low/moderate temperatures revealed that the Antarctic environment contains metabolically diverse cultivable yeasts, which could be considered as a target for biotechnological applications. Among the evaluated yeasts in the present study 46.39, 37.11 and 14.43 % were able to produce lipase (at 15 °C), xylanase (at 15 °C) and protease (at 25 °C), respectively. The majority of lipolytic, proteolytic and xylanolytic strains were distributed in the phylum Basidiomycota and were mainly recovered from sea stars, lichens, sea urchin and marine sediments.
Assuntos
Água do Mar/microbiologia , Microbiologia do Solo , Leveduras/classificação , Regiões Antárticas , Temperatura Baixa , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Lipase/genética , Lipase/metabolismo , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Filogenia , Xilosidases/genética , Xilosidases/metabolismo , Leveduras/enzimologia , Leveduras/genética , Leveduras/isolamento & purificaçãoRESUMO
Leaf-cutting ants (Formicidae: Attini) are considered pests in agriculture for their impact in human crops, as they utilize leaf fragments to raise their fungal mutualist (Agaricales: Lepiotaceae). Basically, the basidiomycetous fungus is cultivated to supply food to adult workers and broads; in return, the ants protect it against natural enemies. However, recent studies have claimed that other microorganisms are associated to ant nests where a wide range of interactions may take place. To investigate the occurrence of dematiaceous fungi on the cuticle of Atta laevigata ants, 30 workers were sampled from an adult nest located in the surroundings of the Center for the Studies of Social Insects, UNESP-Rio Claro, SP, Brazil. The use of selective techniques to avoid high-sporulation fungi has been recommended and was tested in this study. To favor the isolation of the desired fungi, heads and cuticle scrapings of ant bodies were inoculated on Mycosel agar and incubated for 3 weeks at 35°C. Morphological and molecular methods were used to identify the filamentous fungi recovered. From 56 isolates, 19 were hyaline filamentous species, and among the remaining 37, some are mentioned as phyto-associated fungi like Alternaria arborescens, Bipolaris sorokiniana, Bipolaris eleusines, Bipolaris zeae, Curvularia trifolii, and Paraphaeosphaeria michotii. These species are reported from A. laevigata bodies for the first time. None of the isolation trials revealed the presence of the parasite Escovopsis or entomopathogenic fungi. The possible spread of the fungi in nature by the ants is discussed.
Assuntos
Agaricales/isolamento & purificação , Formigas/microbiologia , Agaricales/classificação , Agaricales/genética , Agaricales/fisiologia , Animais , Formigas/fisiologia , Brasil , Dados de Sequência Molecular , Filogenia , SimbioseRESUMO
Leafcutter ants (Formicidae: tribe Attini) are well-known insects that cultivate basidiomycete fungi (Agaricales: Lepiotaceae) as their principal food. Fungus gardens are monocultures of a single cultivar strain, but they also harbor a diverse assemblage of additional microbes with largely unknown roles in the symbiosis. Cultivar-attacking microfungi in the genus Escovopsis are specialized parasites found only in association with attine gardens. Evolutionary theory predicts that the low genetic diversity in monocultures should render ant gardens susceptible to a wide range of diseases, and additional parasites with roles similar to that of Escovopsis are expected to exist. We profiled the diversity of cultivable microfungi found in 37 nests from ten Acromyrmex species from Southern Brazil and compared this diversity to published surveys. Our study revealed a total of 85 microfungal strains. Fusarium oxysporum and Escovopsis were the predominant species in the surveyed gardens, infecting 40.5% and 27% of the nests, respectively. No specific relationship existed regarding microfungal species and ant-host species, ant substrate preference (dicot versus grass) or nesting habit. Molecular data indicated high genetic diversity among Escovopsis isolates. In contrast to the garden parasite, F. oxysporum strains are not specific parasites of the cultivated fungus because strains isolated from attine gardens have similar counterparts found in the environment. Overall, the survey indicates that saprophytic microfungi are prevalent in South American leafcutter ants. We discuss the antagonistic potential of these microorganisms as "weeds" in the ant-fungus symbiosis.
Assuntos
Agaricales/crescimento & desenvolvimento , Formigas/microbiologia , Simbiose , Agaricales/classificação , Agaricales/genética , Animais , Variação Genética , Dados de Sequência Molecular , FilogeniaRESUMO
The aim of this study was to select virulent strains of microfungi against Leucoagaricus gongylophorus, a symbiotic fungus cultivated by leaf-cutting ants. The results from in vitro assays showed that microfungal strains had a variable and significant impact on the colony development of L. gongylophorus. Specifically, Trichoderma harzianum, Escovopsis weberi CBS 810.71 and E. weberi A088 were more effective, inhibiting the L. gongylophorus colonies by 75, 68 and 67%, respectively (P < 0.05) after 15 days. Strain E. weberi A086 and Acremonium kiliense were less effective: 43 and 26%, respectively (P < 0.05). In spite of the current negative perspective of a microbiological control approach for these ants, the present work discusses the possibility of using mycopathogenic fungi for the control of these insects, and points out the importance of encouraging more studies in this area.
Assuntos
Formigas/microbiologia , Basidiomycota/fisiologia , Controle de Insetos/métodos , Fungos Mitospóricos/fisiologia , Animais , Basidiomycota/citologia , Fungos Mitospóricos/citologia , SimbioseRESUMO
Leucoagaricus gongylophorus, the symbiotic fungus of the leaf-cutting ants, degrades starch, this degradation being supposed to occur in the plant material which leafcutters forage to the nests, generating most of the glucose which the ants utilize for food. In the present investigation, we show that laboratory cultures of L. gongylophorus produce extracellular alpha-amylase and maltase which degrade starch to glucose, reinforcing that the ants can obtain glucose from starch through the symbiotic fungus. Glucose was found to repress alpha-amylase and, more severely, maltase activity, thus repressing starch degradation by L. gongylophorus, so that we hypothesize that: (1) glucose down-regulation of starch degradation also occurs in the Atta sexdens fungus garden; (2) glucose consumption from the fungus garden by A. sexdens stimulates degradation of starch from plant material by L. gongylophorus, which may represent a mechanism by which leafcutters can control enzyme production by the symbiotic fungus. Since glucose is found in the fungus garden inside the nests, down-regulation of starch degradation by glucose is supposed to occur in the nest and play a part in the control of fungal enzyme production by leafcutters.
Assuntos
Agaricales/enzimologia , Agaricales/metabolismo , Formigas/microbiologia , Amido/metabolismo , Simbiose , Agaricales/fisiologia , Animais , Formigas/fisiologia , Folhas de Planta/parasitologiaRESUMO
A survey of the filamentous fungi other than the symbiotic one found in association with Atta sexdens rubropilosa colonies was carried out. Different fungal species (27 taxa) were isolated a few days after treating the workers with toxic baits (sulfluramid; Mirex-S), from 40 laboratory and 20 field nests. Syncephalastrum racemosum (54%) and Escovopsis weberi (21%), Trichoderma harzianum (38%) and Fusarium oxysporum (23%) were the prevalent species in laboratory and field nests, respectively. Acremonium kiliense, Acremonium strictum, E. weberi, F. oxysporum, Fusarium solani, Moniliella suaveolens and T. harzianum were found in both nests' groups. We revealed that many filamentous fungi can co-exist in a dormant state inside the nests of these insects and some of them appear to be tightly associated with this environment.
Assuntos
Fungos/classificação , Fungos/isolamento & purificação , Himenópteros/microbiologia , Microbiologia do Solo , Animais , Fungos/crescimento & desenvolvimento , SimbioseRESUMO
Leaf-cutting ants of the genera Atta and Acromyrmex (tribe Attini) are symbiotic with basidiomycete fungi of the genus Leucoagaricus (tribe Leucocoprineae), which they cultivate on vegetable matter inside their nests. We determined the variation of the 28S, 18S, and 5.8S ribosomal DNA (rDNA) gene loci and the rapidly evolving internal transcribed spacers 1 and 2 (ITS1 and ITS2) of 15 sympatric and allopatric fungi associated with colonies of 11 species of leafcutter ants living up to 2,600 km apart in Brazil. We found that the fungal rDNA and ITS sequences from different species of ants were identical (or nearly identical) to each other, whereas 10 GenBank Leucoagaricus species showed higher ITS variation. Our findings suggest that Atta and Acromyrmex leafcutters living in geographic sites that are very distant from each other cultivate a single fungal species made up of closely related lineages of Leucoagaricus gongylophorus. We discuss the strikingly high similarity in the ITS1 and ITS2 regions of the Atta and Acromyrmex symbiotic L. gongylophorus studied by us, in contrast to the lower similarity displayed by their non-symbiotic counterparts. We suggest that the similarity of our L. gongylophorus isolates is an indication of the recent association of the fungus with these ants, and propose that both the intense lateral transmission of fungal material within leafcutter nests and the selection of more adapted fungal strains are involved in the homogenization of the symbiotic fungal stock.
Assuntos
Animais , Formigas , DNA Espaçador Ribossômico , Fungos , Simbiose , Brasil , Variação Genética , Folhas de Planta , Reação em Cadeia da Polimerase , Análise de Sequência de DNARESUMO
Leaf-cutting ants of the genera Atta and Acromyrmex (tribe Attini) are symbiotic with basidiomycete fungi of the genus Leucoagaricus (tribe Leucocoprineae), which they cultivate on vegetable matter inside their nests. We determined the variation of the 28S, 18S, and 5.8S ribosomal DNA (rDNA) gene loci and the rapidly evolving internal transcribed spacers 1 and 2 (ITS1 and ITS2) of 15 sympatric and allopatric fungi associated with colonies of 11 species of leafcutter ants living up to 2,600 km apart in Brazil. We found that the fungal rDNA and ITS sequences from different species of ants were identical (or nearly identical) to each other, whereas 10 GenBank Leucoagaricus species showed higher ITS variation. Our findings suggest that Atta and Acromyrmex leafcutters living in geographic sites that are very distant from each other cultivate a single fungal species made up of closely related lineages of Leucoagaricus gongylophorus. We discuss the strikingly high similarity in the ITS1 and ITS2 regions of the Atta and Acromyrmex symbiotic L. gongylophorus studied by us, in contrast to the lower similarity displayed by their non-symbiotic counterparts. We suggest that the similarity of our L. gongylophorus isolates is an indication of the recent association of the fungus with these ants, and propose that both the intense lateral transmission of fungal material within leafcutter nests and the selection of more adapted fungal strains are involved in the homogenization of the symbiotic fungal stock.
Assuntos
Formigas/fisiologia , DNA Espaçador Ribossômico/genética , Fungos/genética , Variação Genética , Simbiose , Animais , Brasil , Fungos/fisiologia , Folhas de Planta , Reação em Cadeia da Polimerase , Análise de Sequência de DNARESUMO
Killer activity was screened in 99 yeast strains isolated from the nests of the leaf-cutting ant Atta sexdens against 6 standard sensitive strains, as well as against each other. Among this yeast community killer activity was widespread since 77 strains (78%) were able to kill or inhibit the growth of at least one standard strain or nest strain. Toxin production was observed in representatives of all the studied genera including Aureobasidium, Rhodotorula, Tremella and Trichosporon, whose killer activity has not yet been described.
Assuntos
Formigas/microbiologia , Leveduras/isolamento & purificação , Animais , Meios de Cultura , Concentração de Íons de Hidrogênio , Fatores Matadores de Levedura , Micotoxinas/análise , Micotoxinas/isolamento & purificação , Fenótipo , Rhodotorula/isolamento & purificação , Rhodotorula/metabolismo , Especificidade da Espécie , Trichosporon/isolamento & purificação , Trichosporon/metabolismo , Leveduras/classificação , Leveduras/metabolismoRESUMO
The development of Leucoagaricus gongylophorus, the fungus cultured by the leaf-cutting ant Atta sexdens was inhibited in vitro by synthetic compounds containing the piperonyl group. In addition, worker ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls. The inhibition of the fungal growth increased with the size of the carbon side chain ranging from C1 through C8 and decreasing thereafter. 1-(3,4-Methylenedioxybenzyloxy)octane (compound 5) was the most active compound and inhibited the fungal development by 80% at a concentration of 15 micrograms ml-1. With worker ants the toxic effects started with compound 5 and increased with the number of carbons in the side chain. Thus, for the same concentration (100 micrograms ml-1) the mortality rates observed after 8 days of diet ingestion were 82%, 66% and 42%, for 1-(3,4-methylenedioxybenzyloxy)decane, 1-(3,4-methylenedioxybenzyloxy)dodecane and compound 5, respectively, whereas with commercial piperonyl butoxide the mortality was 68%. The latter compound, which is known as a synergist insecticide, was as inhibitory to the symbiotic fungus as the synthetic compound 5. The possibility of controlling these insects in the future using compounds that can target simultaneously both organisms is discussed.
Assuntos
Antifúngicos/farmacologia , Formigas/metabolismo , Fungos/efeitos dos fármacos , Sinergistas de Praguicidas , Butóxido de Piperonila , Animais , Álcoois Benzílicos/análise , Álcoois Benzílicos/química , Álcoois Benzílicos/toxicidade , Bioensaio , Brometos/análise , Brometos/química , Iodetos/análise , Iodetos/química , Sinergistas de Praguicidas/análise , Sinergistas de Praguicidas/química , Butóxido de Piperonila/análise , Butóxido de Piperonila/química , Folhas de Planta/química , SimbioseRESUMO
The hexane extract of the stems of Raulinoa echinata afforded the sesquiterpenes germacrene D (6), 1beta,6alpha-dihydroxy-4-(15)-eudesmene (4) and oplopanone (5); the triterpenes squalene, isomultiflorenol (7), isobauerenol (8) and friedelin (9); the protolimonoids melianone (2) and melianodiol (3); and the pyranocoumarin 3-(1'-1'-dimethylallyl)-lomatin (1), which has not been reported previously as a natural product; together with beta-sitosterol. The hexane extract and some of these compounds were assayed in vitro against trypomastigote forms of Trypanosoma cruzi. Brine shrimp lethality and antimicrobial activities of the crude extract and pure compounds were also evaluated.
Assuntos
Cumarínicos/química , Extratos Vegetais/química , Sesquiterpenos/química , Triterpenos/química , Tripanossomicidas/química , Trypanosoma cruzi/efeitos dos fármacos , Animais , Artemia , Bioensaio , Brasil , Cumarínicos/isolamento & purificação , Cumarínicos/farmacologia , Etnobotânica , Humanos , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Caules de Planta , Plantas Medicinais , Rosales/química , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Triterpenos/isolamento & purificação , Triterpenos/farmacologia , Tripanossomicidas/isolamento & purificação , Tripanossomicidas/farmacologia , Trypanosoma cruzi/parasitologiaRESUMO
Two C,O-diglycosylated compounds, the anthrone picramnioside F, and the oxanthrone mayoside C, were isolated from the stem bark of Picramnia teapensis, along with the previously reported anthraquinones, 1-O-beta-D- and 8-O-beta-D-glucopyranosyl emodin. The compounds were separated by recycling-HPLC, and their structures were determined on the basis of spectroscopic analysis. CD measurements were used to establish the absolute configuration of the anthrone and oxanthrone. The antifungal activity of 1-O-beta-D- and 8-O-beta-D-glucopyranosyl emodin against Leucoagaricus gongilophorus was shown to be similar to that of the lignan sesamin.
Assuntos
Glicosídeos/isolamento & purificação , Rosales/química , Cromatografia Líquida de Alta Pressão , Glicosídeos/química , Estrutura Molecular , Análise EspectralRESUMO
A total of 137 yeasts associated with the leaf-cutting ant Atta sexdens rubropilosa Forel, 1908 were characterized, being selected 93 for analysis. Twenty four species belonging to seven genera (Candida, Cryptococcus, Rhodotorula, Sporobolomyces, Tremella, Trichosporon, Pichia) were isolated from the different analysed material. The genus Candida was widely distributed, with C. homilentoma, C. colliculosa-like, C. famata and C. colliculosa being the most prevalent. A few isolates did not fit the standard descriptions and probably some of them could be new biotypes or even new species. Three strains of black yeasts were also isolated, and four other were identified as being Candida spp. The effective number of yeast species was higher in newer sponge. The origin, distribution and relative importance of these microorganisms for the ants are discussed.
Assuntos
Formigas/microbiologia , Leveduras/classificação , Leveduras/isolamento & purificação , Animais , Técnicas Bacteriológicas , Candida/classificação , Candida/isolamento & purificaçãoRESUMO
The number and the main groups of microorganisms present in samples of different nonalcoholic carbonated beverages (lemon, orange and guaraná soft drinks) obtained from small factory were analyzed. The samples were obtained at the end of the processing line. They were then divided into two lots: one was sent to immediate analysis, the other was stored at environmental temperature for 90 d thereafter it was submitted to the same analysis. Aliquots of 1 mL were drawn from the various samples and the corresponding decimal dilutions were prepared. They were then grown in culture media and counts of mesophilic aerobic bacteria, molds and yeasts, acid-producing bacteria, total and fecal coliforms were taken. It was observed that, of all the analyzed samples, at time 0 or storage sample C (orange) was the best, since it conformed to the microbiological standards established by legislation. The guaraná type could also be consumed on day zero; the lemon type was inadequate for consumption of all the analyzed samples, the orange type was the only one that could be consumed within 3 months of storage.
Assuntos
Bebidas Gaseificadas/microbiologia , Microbiologia de Alimentos/normas , Brasil , Contagem de Colônia Microbiana , Microbiologia de Alimentos/legislação & jurisprudência , Frutas , Controle de QualidadeRESUMO
Fruits from twenty different species of angiosperms were collected during the period from November, 1991 to January, 1992. Two hundred and two strains of yeasts and yeast-like fungi were isolated, of which 74% showed ascomycetic affinity. Candida was the predominant genus, followed by (in descending order of occurrence): Cryptococcus, Kloeckera, Sporobolomyces, Pichia, Hanseniaspora and Bullera. Black yeasts and other strains showing basidiomycetic affinity were also isolated. The genus Candida represented the highest number of identified species and the greatest variety of associated substrates. Among the ascomycetes and their anamorphs, 38 species were identified, with Kloeckera apiculata being the most frequent among the isolates and the one which occurred in the largest variety of substrates. Some of the biotypes designated as Candida sp. A, B, C, D, E, F, G, H, I, and Pichia sp. did not correspond to the standard species description found in the literature, and may represent new species. The strains of yeasts isolated in this study were characterized and incorporated into the Tropical Culture Collection of the Fundaao Tropical de Pesquisas e Tecnologia Andre Tosello, Campinas, São Paulo.
Assuntos
Ascomicetos/isolamento & purificação , Frutas/microbiologia , Ascomicetos/classificação , Brasil , Candida/classificação , Candida/isolamento & purificação , Ecossistema , Especificidade da Espécie , Clima TropicalRESUMO
Lignans fromVirola sebifera Aubl.,Virola sp., andOtoba parvifolia (Mkfg.) A. Gentry (Myristicaceae) inhibited the in vitro growth of the fungus cultivated by leaf-cutting ants of the speciesAtta sexdens rubropilosa Forel (Hymenoptera: Formicidae). A comparison of activity among the lignans was obtained.
RESUMO
Leucocoprinus gongylophorus, the fungus cultured by the leaf-cutting ant Atta sexdens rubropilosa, is able to degrade efficiently cellulose, microcrystaline cellulose, carboximethylcellulose, and cellobiose. Analysis of the degradation products indicate that the fungus produce extracellular beta-glucosidase, exo- and endo-glucanase. The importance of cellulose degradation to the association of fungus and ant is discussed.