Communities of anamorphic fungi on green leaves and leaf litter of native forests of Scutia buxifolia and Celtis tala: Composition, diversity, seasonality and substrate specificity / Comunidades de hongos anamórficos en hojas verdes y hojarasca de bosques nativos deScutia buxifolia y Celtis tala: composición, diversidad, estacionalidad y especificidad del sustrato

Background: Xeric forests dominated by two tree species, Scutia buxifolia (Rhamnaceae) and Celtis tala (Ulmacea), are temperate, semi-deciduous wooded communities that represent the most abundant woodlands on the eastern plains of Buenos Aires Province, Argentina. The district of Magdalena has one of the most well-preserved native-forest areas, with an environmental heterogeneity that gives rise to the wide variability in the vegetation present. Aims: The aim of this study was to analyze the species composition, diversity, seasonal variations, and substrate specificity of anamorphic fungi (Ascomycota) on the green leaves and in the leaf litter of native forests dominated by Scutia buxifolia and Celtis tala from Magdalena, Buenos Aires, Argentina. Methods: In order to obtain the mycobiota of decomposition, seasonal samples of green leaves and leaf litter from both types of trees were collected over a two-year period. In the laboratory, the leaves were placed in a moist chamber and incubated at room temperature. Results: A total of 100 species of anamorphic Ascomycota were identified in both forests. No significant variations were observed in the richness, diversity, or evenness of the fungal communities of the green leaves and leaf litter of both forests between seasons. Conclusions: The species that characterized the fungal communities in the leaves of each of the trees were found to be different. The type of substrate had a stronger influence in determining the composition of the fungal community in both types of forests (AU)

Antecedentes: Los bosques xerófilos dominados por las especies arbóreas Scutia buxifolia (Rhamnaceae) y Celtis tala (Ulmaceae) conforman comunidades boscosas semicaducas y templadas que constituyen los bosques nativos más abundantes de la provincia de Buenos Aires, Argentina. En el distrito de Magdalena constituyen una de las comunidades naturales de este tipo mejor conservada, con una heterogeneidad ambiental que da lugar a la gran variabilidad en la composición de la vegetación presente. Objetivos: El objetivo del presente trabajo fue analizar las distribución de especies, la diversidad, las variaciones estacionales y la especificidad por el sustrato de hongos anamórficos (Ascomycota) presentes en las hojas verdes y en la hojarasca de los bosques nativos xerófilos dominados por las especies arbóreas Scutia buxifolia y Celtis tala en el partido de Magdalena, provincia de Buenos Aires, Argentina. Métodos: Para obtener la micobiota descomponedora se tomaron muestras estacionales de hojas verdes y hojarasca de los 2 tipos de árboles durante un período de 2 años. En el laboratorio, las hojas se colocaron en cámara húmeda y se incubaron a temperatura ambiente. Resultados: Se identificaron 100 especies de anamorfos de la división Ascomycota en las hojas de ambos tipos de árboles. No se observaron diferencias en cuanto a la diversidad, equidad y riqueza de especies entre ambos tipos de hojas. Conclusiones: Las especies que componen la comunidad fúngica de las hojas de Scutia buxifolia y Celtis tala es diferente. El tipo de sustrato que representan las hojas de cada especie arbórea condiciona la composición de la comunidad de anamorfos de Ascomycota presentes en ambos tipos de hoja (AU)

Aislamiento y evaluación de la actividad enzimática de hongos descomponedores de madera (Quindío, Colombia) / Isolation of wood-decaying fungi and evaluation of their enzymatic activity (Quindío, Colombia)

Se realizó la colecta de hongos (rdas.) en troncos caídos con diferentes estados de descomposición en un bosque subandino (la reserva natural La Montaña del Ocaso) y se evaluó su actividad ligninolítica. Se cultivaron en Agar extracto de malta y se realizaron pruebas semicuantitativas de actividad lacasa utilizando como inductor enzimático el ácido 2,2’azino-bis-[3-etilbenzotiazolin-6-sulfónico] y el 2,6-diclorofenolindofenol para la celobiosa deshidrogenasa (CDH). Se seleccionaron los hongos con mayor actividad enzimática de troncos con diferente grado de descomposición: Cookeina sulcipes (de estado 1), un hongo de la familia Corticiaceae (de estado 2), Xylaria polymorpha (de estado 3) y Earliella sp. (de estado 4). La fermentación se realizó a 28°C durante 11 días, a 150r.p.m., con mediciones diarias para biomasa, glucosa, actividad lacasa, actividad CDH y proteínas. Los hongos de los troncos con estados de descomposición 1 a 3 presentaron mayor actividad lacasa, a medida que aumentaba el estado de descomposición. Hubo un aumento en la actividad CDH a medida que se incrementó el estado de descomposición de los troncos. Hubo una relación positiva entre la producción de las 2 enzimas. Earliella sp. fue el hongo con mayor producción de biomasa (1.140,19g/l), actividad lacasa (157Ul−1) y CDH (43,50Ul−1). Este trabajo es el primer reporte de actividad lacasa y CDH en C. sulcipes y Earliella sp. Además, sienta las bases para la utilización de estos hongos nativos en aplicaciones biotecnológicas y se adentra en el conocimiento de su función dentro del proceso de descomposición de la madera en bosques(AU)

White rotfungi(AscomycotaandBasidiomycota)werecollectedonfallentrunkswithdifferentdecaystages, inasubandeanforest(LaMontan˜a delOcasonaturereserve),anditwasevaluatedtheirligninoliticactivity.Theywereculturedonmaltextractagar.Thenitwasperformedsemiquantitativetestsforlaccaseand cellobiosedehydrogenase(CDH)activityusingABTSandDCPIPasenzymaticinducers.Basedontheresults ofthesetests,thefungiwithhigheractivitiesfromtrunkswithdifferentdecaystageswereselected:Cookeina sulcipes (for stage1),afungusfromthefamilyCorticiaceae(forstage2), Xylariapolymorpha (forstage 3)and Earliella sp. (forstage4).Afermentationwasperformedat28 1C, during11days,inarotatoryshaker at150rpm.Biomass,glucose,proteinsandenzymeactivitiesmeasurementswereperformeddaily.The fungithatwereinthetrunkswithdecaystatesfrom1to3,showedhigherlaccaseactivityasthestateof decayincreased.AhigherDCHactivitywasalsoassociatedwithahigher.Also,therewasapositiverelationship betweenbothenzymes’activities.Erliellawasthefunguswhichpresentedthehighestbiomass production(1140,19g/l),laccaseactivity(157UL 1) andCDHactivity(43,50UL 1). Thisworkisthefirst reportoflaccaseandCDHactivityfor Cookeina sulcipes and Earliella sp. Moreover,itgivesbasisforthe useofthesenativefungiinbiotechnologicalapplicationsandtheacknowledgmentoftheirfunctioninthe wooddecayprocessinnativeforest

PCR-based DGGE and FISH analysis of methanogens in an anaerobic closed digester tank for treating palm oil mill effluent

16S ribosomal RNA (rRNA)-targeted fluorescent in situ hybridization combined with polymerase chain reaction (PCR)-cloning, light microscopy using Gram stains, scanning electron microscopy and denatured gradient gel electrophoresis were used to reveal the distribution of methanogens within an anaerobic closed digester tank fed with palm oil mill effluent. For specific detection of methanogens, 16S rRNA-cloning analysis was conducted followed by restriction fragment length polymorphism (RFLP) for presumptive identification of methanogens. To cover the drawbacks of the PCR-cloning study, the organization of the microorganisms was visualized in the activated sludge sample by using fluorescent oligonucleotide probes specific to several different methanogens, and a probe for bacteria. In situ hybridization with methanogens and bacterial probes and denatured gradient gel electrophoresis within activated sludge clearly confirmed the presence of Methanosaeta sp. and Methanosarcina sp. cells. Methanosaeta concilii was found to be the dominant species in the bioreactor. These results revealed the presence of possibly new strain of Methanosaeta in the bioreactor for treating palm oil mill effluent called Methanosaeta concilii SamaliEB (Gene bank accession number: EU580025). In addition, fluorescent hybridization pictured the close association between the methanogens and bacteria and that the number of methanogens was greater than the number of bacteria.

Performance of an Anaerobic Baffled Reactor (ABR) in treatment of cassava wastewater / Desempenho de um Reator Anaeróbio Compartimentado (RAC) no tratamento da manipueira

The performance of an anaerobic baffled reactor (ABR) was evaluated in the treatment of cassava wastewater, a pollutant residue. An ABR divided in four equal volume compartments (total volume 4L) and operated at 35ºC was used in cassava wastewater treatment. Feed tank chemical oxygen demand (COD) was varied from 2000 to 7000 mg L-1 and it was evaluated the most appropriated hydraulic retention time (HRT) for the best performance on COD removal. The ABR was evaluated by analysis of COD (colorimetric method), pH, turbidity, total and volatile solids, alkalinity and acidity. Principal component analysis (PCA) was carried to better understand data obtained. The system showed buffering ability as acidity decreased along compartments while alkalinity and pH values were increased. There was particulate material retention and COD removal varied from 83 to 92% for HRT of 3.5 days.

O desempenho de um reator anaeróbio compartimentado (RAC) foi avaliado para o tratamento da manipueira, resíduo tóxico. Um RAC dividido em quatro compartimentos de mesmo volume (volume total 4L) e operado a 35ºC foi utilizado no tratamento da manipueira. A demanda química de oxigênio (DQO) do tanque de alimentação variou de 2000 a 7000 mg L-1 e avaliou-se o tempo de residência hidráulica (TRH) mais apropriado ao melhor desempenho do reator. O RAC foi avaliado pelas análises de DQO (método colorimétrico), pH, turbidez, sólidos totais e voláteis, alcalinidade e acidez. A Análise das Componentes Principais (PCA) foi conduzida para melhor compreensão dos dados obtidos. O sistema apresentou capacidade tamponante conforme a acidez decresceu ao longo dos compartimentos ao passo que a alcalinidade e o pH aumentaram. Houve retenção do material particulado e a remoção da DQO variou de 83 a 92% para TRH de 3,5 dias.

Macromolecular composition and anaerobic degradation of the sludge produced in a sequencing batch reactor

The effect of sequencing batch reactor (SBR) operating conditions on sludge macromolecular composition and the effect of sludge macromolecular composition on the anaerobic degradation of the sludge produced in SBR was investigated in this work. A SBR, fed with synthetic wastewater, was operated at different air flow rates. The resulting sludge was analyzed in terms of protein, carbohydrate, phospholipid and polyhydroxybutyrate concentrations. Methane production during anaerobic digestion of the sludge was also measured. Ammonium, nitrite, nitrate, dissolved oxygen and chemical oxygen demand (COD) track studies in the SBR were carried out in order to relate SBR performance and sludge macromolecular composition. The lowest air flow rate at which the SBR was operated was 2 l min-1, in which case the dissolved oxygen concentration was lower than 0.5 mg l-1 in the SBR and partial denitrification occurred during the feeding phase. An increased air flow rate caused a decrease in protein concentration, as well as an increase in carbohydrate concentration. Polyhydroxybutyrate (PHB) concentration in the sludge was independent of air flow rate. At different air flows, the methane production rates were similar, but the total volume of methane was greater during anaerobic digestion of the sludge produced at low air flow rates. These results indicate a strategy by which changes in sludge composition can optimize the operation of anaerobic sludge digesters.

Descomposición de hojas de Tessaria integrifolia (Asteraceae) y colonización por invertebrados en un cause secundario del río Paraná medio / Descomposition and invertebrate colonization of Tessaria integrifolia (Asteraceae) leaves in a secondary channel of the middle Paraná river

Se analizó la descomposición de hojas de Tessaria integrifolia y su colonización por invertebrados en el río Tiradero Viejo, cauce secundario del río Paraná, Argentina. Las hojas de T. integrifolia fueron recolectadas después de la abscisión; se colocaron 6g de hojas secadas al aire en bolsas de nylon de 5mm de abertura de malla y fueron expuestas al proceso de descomposición en la ribera del río. Se extrajeron 3 réplicas a los 7, 14, 28, 56 y 112 días. El coeficiente de descomposición (k) obtenido fue de 0,0143 a los 112 días. La densidad máxima de invertebrados fue de 395 individuos/g de peso seco de hojas a los 56 días de exposición. La mayor riqueza de especies y diversidad fueron obtenidas a los 28 días, siendo los oligoquetos (Pristina leidyi, P. aequiseta, Dero multibranchiata), quironómidos (Polypedilum spp., Phaenopsectra sp.) y bivalvos (Limnoperna fortunei) los taxa dominantes. Los colectores-recolectores fueron dominantes durante las primeras etapas de la sucesión y los colectores-filtradores aumentaron en las etapas finales, mientras que los trituradores fueron escasos pero más constantes a lo largo de la experiencia.