Mercury concentration in larvae of Eustrongylides sp (Nematoda: Dioctophymatoidea) from fish of the Brazilian Amazon / Concentración de mercurio en larvas de Eustrongylides sp (Nematoda: Dioctophymatoidea) en peces de la Amazonía brasileña

Abstract Introduction: Chemical pollution represents a great concern to aquatic organisms, especially fish. Metals enter the aquatic environment from a variety of sources, including natural biogeochemical cycles and anthropogenic sources such as industrial and residential effluents, mining and atmospheric sources. Objective: To describe the Eustrongylides sp. larvae and the interaction with their fish hosts as indicators of mercury (Hg) contamination in the Brazilian Amazon, and the distribution of Hg in the internal organs of fish species Hoplias malabaricus and Pygocentrus nattereri collected in oxbow lakes on the Tapajós River, in the municipality of Santarém, in the state of Pará. Methods: Total Hg was analyzed using the Direct Hg Analyzer - DMA-80. Concentrations of Hg in Eustrongylides sp. were compared with those found in the tissues/organs of the hosts H. malabaricus and P. nattereri. Hg concentrations in the host/parasite system were statistically compared using Principal Component Analysis. The bioconcentration factor (BCF) was calculated to assess the bioaccumulation capacity of metals in Eustrongylides sp. larvae, comparing the concentration of Hg in the parasite with that accumulated in the musculature of infected hosts. Results: Hg concentrations in all tissues/organs analyzed were higher in the parasitic species Eustrongylides sp. larvae when compared with those found in tissues/organs of H. malabaricus and P. nattereri. There was an inversely proportional relationship, showing that when Eustrongylides sp. larvae are present, the concentration in the parasite is higher than in the musculature of host fish H. malabaricus and P. nattereri. The BCF of Hg was found by comparing Eustrongylides sp. larvae/H. malabaricus muscle and was observed during a flood (BCF Hg = 15 364). Conclusions: The results confirm the greater bioaccumulative capacity of Eustrongylides sp. compared to its host. The data indicated the viability of using Eustrongylides sp. larvae in biomonitoring programs. It is worth mentioning that fish samples for Hg analysis must be free of parasites since their presence can alter the results.

Resumen Introducción: La contaminación química del hábitat acuático representa un gran peligro para organismos acuáticos, especialmente para peces. Los metales ingresan al ambiente acuático desde una variedad de fuentes, incluidos los ciclos biogeoquímicos naturales y fuentes antropogénicas, como efluentes industriales y residenciales, minería y fuentes atmosféricas. Objetivo: Describir las especies de Eustrongylides sp. y la interacción con sus peces hospederos como indicadores de contaminación por mercurio en la Amazonía brasileña, y la distribución en los órganos internos de las especies de peces Hoplias malabaricus y Pygocentrus nattereri recolectadas en cochas del Río Tapajós, en el municipio de Santarém, del estado de Pará. Métodos: El Hg total se analizó utilizando el Direct Hg Analyzer - DMA-80. Las concentraciones de Eustrongylides sp. se compararon con las encontrados en los tejidos/órganos de los hospederos H. malabaricus y P. nattereri. Las concentraciones en el sistema hospedero/parásito se compararon estadísticamente utilizando el análisis de componentes principales. Se calculó el factor de bioconcentración (BCF) para evaluar la capacidad de bioacumulación de metales en larvas de Eustrongylides sp., comparando la concentración en el parásito con la acumulada en la musculatura de los hospederos infectados. Resultados: Las concentraciones de Hg en todos los tejidos/órganos analizados fueron mayores en las larvas de la especie parasitaria Eustrongylides sp. en comparación con las encontradas en los tejidos/órganos de H. malabaricus y P. nattereri. Hubo una relación inversamente proporcional, mostrando que cuando las larvas de Eustrongylides sp. están presentes, la concentración en el parásito es mayor que en la musculatura de los peces hospederos H. malabaricus y P. nattereri. El BCF de Hg se encontró comparando Eustrongylides sp. larvas/ músculo H. malabaricus y se observó durante una inundación (BCF Hg = 15 364). Conclusiones: Los resultados confirman la mayor capacidad bioacumulativa de Eustrongylides sp. en comparación con su hospedero. Los datos indicaron la viabilidad de utilizar larvas de Eustrongylides sp. en programas de biomonitoreo. Cabe mencionar que las muestras de pescado para análisis de Hg deben estar libres de parásitos ya que su presencia puede alterar los resultados.

In vitro efficacy of Duddingtonia flagrans against nematodes of sheep based on in vivo calculations / Eficácia in vitro de Duddingtonia flagrans contra nematoides de ovinos com base em cálculo in vivo

Abstract Duddingtonia flagrans has been tested as an alternative parasite control, but data from in vitro experiments based on in vivo calculations describing nematophagous fungi predation in nematodes are restricted. The objective of this work was to determine the efficacy of D. flagrans against sheep nematode larvae in vitro using in vivo calculations. Fecal samples were introduced to fungi in different concentrations: 0.0/control; 0.05; 0.1; 0.2; 0.4; 0.8; 1.6; 3.2; and 6.4 g corresponding, respectively, to 583.000; 1.166.000; 2.332.000; 4.664.000; 9.328.000; 18.656.000; 37.312.000 and 74.624.000 chlamydospores/kg of body weight. The material was incubated for 14 days, before the larvae recovery (Assay 1). Assay 2 was carried out with the doses of 0.00625; 0.0125; and 0.025 g. The results showed a negative correlation between fungal concentrations and larval numbers for both assays. The fungus demonstrated an efficacy above 89% in both assays. Thus, we consider that the data from in vitro studies based on in vivo calculations may optimize the fungi quantities for field experiments.

Resumo Duddingtonia flagrans tem sido testado como uma alternativa no controle de parasitos, entretanto, trabalhos in vitro da predação de nematoides por fungos nematófagos correlacionados com cálculos baseados para testes in vivo são restritos. O objetivo deste trabalho foi determinar a eficácia in vitro de D. flagrans contra larvas de nematoides de ovinos tendo como base cálculos in vivo. Amostras fecais receberam a adição do fungo em diferentes concentrações: 0.0/controle; 0,05; 0,1; 0,2; 0,4; 0,8; 1,6; 3,2 e 6,4 gramas correspondendo, respectivamente, às seguintes dosagens: 583.000; 1.166.000; 2.332.000; 4.664.000; 9.328.000; 18.656.000; 37.312.000 e 74.624.000 clamidósporos/Kg de peso vivo animal. O material foi incubado por 14 dias, para recuperação das larvas (Ensaio 1). O Ensaio 2 foi realizado com concentrações de 0,00625; 0,0125 e 0,025 g. Foi observada correlação negativa entre a concentração fúngica e o número de larvas, nos dois ensaios. O fungo demonstrou eficácia acima de 89% em ambos os ensaios. A partir destes dados, acreditamos que ensaios in vitro baseados em cálculos in vivo podem aprimorar as dosagens para a realização de experimentos a campo.

Control of infective larvae of gastrointestinal nematodes in heifers using different isolates of nematophagous fungi / Controle de larvas infectantes de nematóides gastrintestinais de novilhas por diferentes isolados dos fungos nematófagos

The effect of different nematophagous fungi [Duddingtonia flagrans (AC001 and CG722) and Monacrosporium thaumasium (NF34)] with regard to controlling infective larvae (L3) of nematodes after gastrointestinal transit in female cattle (3/4 Holstein × Zebu) was evaluated. A total of 24 pubescent female cattle were used, weighing approximately 320 kg each one. There were three treatment groups, each contained six animals that received 150 g of pellets (0.2 g of mycelium), orally in a single dose, in a sodium alginate matrix containing mycelial mass of the fungus D. flagrans (AC001 or CG722) or M. thaumasium (NF34); and one control group (without fungi). Fecal samples were collected from the animals at intervals of 12, 15, 18, 21, 24, 48, and 72 hours. At the end of 17 days, the L3 not subjected to predation were recovered by means of the Baermann method. The fungal isolates tested were capable of destroying the L3 after gastrointestinal transit. It was observed that within 72 hours, the isolates AC001, CG722, and NF34 showed a higher predatory activity (81.2%, 97.3%, and 98.3%, respectively). The results justify the need for studies in the field, and over longer intervals, in order to observe the efficiency of the fungus D. flagrans, or even M. thaumasium, for environmental control over nematodes in naturally infected cattle.

No presente estudo, foi avaliado o efeito de diferentes fungos nematófagos [Duddingtonia flagrans (AC001 e CG722) eMonacrosporium thaumasium (NF34)] no controle de larvas infectantes (L3) de nematóides após o trânsito gastrointestinal em fêmeas bovinas (3/4 Holandês x Zebu). Um total de 24 fêmeas bovinas pubescentes foram utilizadas, pesando aproximadamente 320 kg cada. Foram utilizados três grupos de tratamento; cada um contendo seis animais que receberam por via oral de 150 g de péletes (0,2 g de micélio), em dose única, em uma matriz de alginato de sódio contendo massa micelial dos fungos D. flagrans (AC001 ou CG722), M. thaumasium (NF34), além de um grupo controle (sem fungo). Amostras de fezes foram colhidas dos animais em intervalos de 12, 15, 18, 21, 24, 48 e 72 horas. No final de 17 dias, as L3 não predadas foram recuperadas pelo método de Baermann. Os isolados de fungos testados foram capazes de destruir as L3 após trânsito gastrointestinal. Observou-se após 72 horas, os isolados AC001, CG722 e NF34 mostraram uma maior atividade predatória (81,2%, 97,3% e 98,3%, respectivamente). Estes resultados justificam a necessidade de estudos a campo e em intervalos mais longos, a fim de observar a eficácia dos fungos D. flagrans ou mesmoM. thaumasium no controle ambiental dos nematóides de bovinos naturalmente infectados.

First report of interaction of nematophagous fungi on Libyostrongylus douglassii (Nematoda: Trichostrongylidae) / Primeiro relato da interação de fungos nematófagos sobre Libyostrongylus douglassii (Nematoda: Trichostrongilidae)

Libyostrongylus douglassii is a gastrointestinal nematode parasite of ostriches that can cause up to 50% mortality in young birds. The objective of this study was to compare the predatory capacity of two isolates of the predatory fungi Duddingtonia flagrans(AC001 and CG722 isolates) and one of Arthrobotrys cladodes (CG719) on infective larvae (L3) of L. douglassii under laboratory conditions, in 2% water-agar medium. The results showed that the fungi tested were effective in preying upon the L3 of L. douglassii (P < 0.05), compared with the control group. However, there was no difference in predatory capacity between the fungi tested (P > 0.05) during the seven days of experimental testing. In comparison with the control, without fungus, there were significant decreases (P < 0.05) of 85.2% (AC001), 81.2% (CG722) and 89.2% (CG719) in the average numbers of L3 of L. douglassii recovered from treatments with the isolates tested. In the present study, the three isolates of the predatory fungi D. flagrans (AC001 and CG722) and A. cladodes (CG719) were efficient at in vitro destruction of the L3 of L. douglassii.

Libyostrongylus douglassii é um nematóide parasito gastrintestinal de avestruzes que pode causar até 50% de mortalidade em aves jovens. O objetivo deste trabalho foi comparar a capacidade predatória de dois isolados de fungos predadores Duddingtonia flagrans (isolados AC001 e CG722) e um Arthrobotrys cladodes (CG719) sobre larvas infectantes (L3) de L. douglassii em condições laboratoriais, em meio ágar­água 2%. Os resultados demonstraram que os fungos testados foram eficientes em predar as L3 de L. douglassii (P < 0,05) em relação ao grupo controle. Contudo, não foi observada nenhuma diferença na capacidade predatória entre os fungos testados (P > 0,05) durante os sete dias do ensaio experimental. Em comparação ao controle, sem fungo, houve uma redução significativa (P < 0,05) de 85,2% (AC001); 81,2% (CG722) e 89,2% (C719) na média de L3 recuperadas nas placas do grupo tratado com os isolados testados. No presente trabalho, os três isolados de fungos predadores D. flagrans (AC001 e CG722) e A. cladodes (CG719) foram eficientes na destruição in vitro das L3 de L. douglassii.

In-vitro predatory activity of nematophagous fungi from Costa Rica with potential use for controlling sheep and goat parasitic nematodes

In tropical and subtropical regions of the world, parasitic diseases are a main cause of losses in livestock productivity. The increased acquired resistence to anthelmintics by gastrointestinal nematodes, requires biological control be considered as a potential feasible and effective alternative. The most effective natural soil enemies of nematodes are nematophagous fungi. In order to collect and identify predator nematophagous fungi (PNF), samples were obtained from 51 farms distributed throughout the seven provinces of Costa Rica. The origin samples included: soil from different crops (potatoes, tomatoes, bananas, ornamental plants, squash and coffee); animal feces (cattle, sheep, goat and horse); soil and fallen leaves from forest; and plants with signs of nematode infection. Each sample was processed using three techniques for the extraction of fungi from soil: sprinkling technique, soil dilution and humidity chamber. Twenty four strains of nematophagous fungi were found in 19 farms; 83.3% of the fungi were isolated by sprinkling technique. The following fungi were idenified: Arthrobotrys oligospora (n=13); Candelabrella musiformis (n=9); and for the first time there was isolation of A. conoides (n=1) and A. dactyloides (n=1) in the country. Moreover, 16 strains from Trichoderma (n=13), Beauveria (n=1), Clonostachys (n=1) and Lecanicillium (n=1) were obtained. In addition, pH of each possible fungal isolation source was measured, and it varied from 5.2 to 9.9, however PNF isolates fell within the range of 5.6 to 7.5. The PNF strains were cultivated in four different media for the production of chhlamydospores: potato dextrose agar (PDA); corn meal agar (CMA); malt extract agar (MEA) and potato carrot agar (PCA). Out of these cultures, 95.8% of the strains formed chlamydospores primarily in the PCA. Of these strains, the profilic spore producers were subjected to ruminant artificial gastrointestinal conditions. A total of 14 fungi were tested, out of which 42.9% survived the digestive analysis. Neither A. conoides nor A. dactyloides were viable following the in vitro gastrointestinal test. The PNF isolated in this study demostrated an action against ovine and caprine gastrointestinal nematodes and are candidates for use in biological control of these organisms. Among these microorganisms, Candelabrella musiformis appears to be the most promising fungi for use as a biological control agent in Costa Rica. Rev. Biol. Trop. 59 (1): 37-52. Epub 2011 March 01.

El control biológico es en la actualidad una alternativa para el control de los nematodos gastrointestinales que desarrollaron resistencia a los principales grupos de antihelmínticos. Para el aislamiento e identificación de hongos nematófagos depredadores, se tomaron muestras de 51 fincas distribuidas entre todas las provincias de Costa Rica. La naturaleza de las muestras incluyó: suelos de diferentes sembradíos (papa, tomate, banano, plantas ornamentales, chayote y café), heces de animales (bovinos, ovinos, caprinos y equinos), suelo y hojarasca de bosques y plantas con signos de enfermedad causada por nematodos. Las muestras se procesaron mediante 3 técnicas diferentes para la extracción de hongos a partir del suelo: espolvoreado en placa, dilución de suelos y cámara húmeda. Veinticuatro cepas de hongos nematófagos fueron aisladas de 19 fincas; el 83.3% de éstos fueron aislados mediante las técnica de espolvoreado en placa. Los hongos fueron identificados como: Arthrobotrys oligospora (n=13), Candelabrella musiformis (n=9) y por primera vez se reporta el aislamiento de A. conoides (n=1) y A. dactyloides (n=1) en el país. Asimismo, se aislaron 16 cepas de hongos de los géneros Trichoderma (n=13), Beauveria (n=1), Clonostachys (n=1) y Lecanicillium (n=1). Adicionalmente se les midió el pH, el cual varió entre 5.2-9.9, ubicándose los HND dentro de un rango entre 5.6-7.5. Las cepas de HND fueron cultivadas en 4 medios diferentes para la producción de clamidosporas: papa dextrosa agar, harina de maíz, extracto de malta y agar papa-zanahoria. El 95.8% de las cepas aisladas produjeron clamidosporas, principalmente en el medio agar papa-zanahoria. De estas cepas, se escogieron las de mayor producción para ser sometidas a la prueba de digestibilidad in vitro. Un total de 14 cepas fueron sometidos a esta prueba, de las cuales el 42.9% resultaron viables; de éstas, las cepas de A. conoides y A. dactyloides no sobrevivieron a la prueba de digestibilidad in vitro. De los microorganismos aislados, Candelabrella musiformis se considera el más promisorio de los hongos como agente biológico en Costa Rica.

Resistência anti-helmíntica de nematóides gastrintestinais em ovinos, Mato Grosso do Sul / Anthelmintic resistance of gastrointestinal nematodes in sheep, Mato Grosso do Sul, Brazil

Entre os métodos de controle da verminose gastrintestinal em ovinos, a utilização de produtos químicos é o mais empregado. Porém, o uso indiscriminado e continuado desses produtos tem selecionado populações de helmintos resistentes aos anti-helmínticos, fenômeno relatado no mundo todo. Este trabalho teve como objetivo identificar as espécies de parasitos gastrintestinais e diagnosticar a situação da resistência anti-helmíntica em ovinos no Estado de Mato Grosso do Sul. Foram realizados testes de redução na contagem de ovos por grama de fezes (OPG) em rebanhos de dezesseis propriedades rurais; as sete formulações utilizadas continham as seguintes bases farmacológicas: Albendazol, Ivermectina, Levamisole, Triclorfon, Moxidectina, Closantel e uma contendo as três primeiras associadas. As espécies identificadas nas necropsias, em ovinos adultos, foram: Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, C. punctata, C. pectinata e Oesophagostomum columbianum; em ordem de prevalência. As formulações contendo Albendazol e Ivermectina não apresentaram eficácia na redução de OPG nos rebanhos testados, com médias de redução de 0,7 e -19,6 por cento, respectivamente. Closantel apresentou eficácia média de 6,7 por cento; Levamisole, Moxidectina e Triclorfon de 28,7, 26,8 e 65 por cento, respectivamente; a associação das três bases (Albendazol, Ivermectina e Levamisole), uma média de eficácia de 55,8 por cento. As percentagens médias de larvas infectantes recuperadas nas coproculturas, tanto no pré como no pós-tratamento, foram semelhantes; indicando que a resistência às bases testadas está presente em todas as espécies citadas, em maior ou menor intensidade. Os dois gêneros predominantemente resistentes são Haemonchus sp., com 86,9 por cento; seguido por Trichostrongylus sp., com média de 47,5 por cento; Strongyloides sp. 33,6 por cento; Oesophagostomum, sp. 21,4 por cento e Cooperia sp. 19,7 por cento.

Among the methods of control of gastrointestinal worms in sheep, the use of chemicals is the most common. However, the continued, and indiscriminate, use of these products has selected populations of resistant helminths to anthelmintics, a phenomenon reported in the whole world. This study aimed to identify the species of gastrointestinal parasites and diagnose the status of anthelmintic resistance in sheep in the State of Mato Grosso do Sul Brazil. Feacal egg count reduction tests (FECRT) were performed in flocks of sixteen farms, and the seven formulations used contained the following pharmacological bases: Albendazole, Ivermectin, Levamizol, Trichlorfon, Moxidectin, Closantel and one containing the first three in association. The species identified at necropsy, in adult sheep, were: Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, C. punctata, C. pectinata and Oesophagostomum columbianum, in order of prevalence. The formulations containing Albendazole and Ivermectin did not show efficacy in reducing the EPG in the flocks tested, with average reductions of 0.7 and -19.6 percent, respectively. Closantel presented an average efficacy of 6.7 percent; Levamisolee, Moxidectin and Trichlorfon, 28.7, 26.8 and 65 percent respectively, the combination of three bases (Albendazole, Ivermectin and Levamizol), an average efficacy of 55.8 percent. The average percentages of infective larvae recovered in the faecal cultures, pre and post treatment were similar, indicating that resistance to the bases tested is present in all species cited, to a greater or lesser degree. The two genera predominantly resistant are Haemonchus sp., with 86.9 percent, followed by Trichostrongylus sp., with an average of 47.5 percent, Strongyloides sp. 33.6 percent, Oesophagostomum sp. 21.4 percent and Cooperia sp. 19.7 percent.

Avaliação in vitro do fungo predador de nematoides Duddingtonia flagrans sobre larvas infectantes de ciatostomíneos de equinos (Nematoda: Cyathostominae) / In vitro evaluation of nematode predacious fungus Duddingtonia flagrans on cyathostomes infective larvae of equines (Nematoda: Cyathostominae)

A capacidade predatória de um isolado de fungo predador de nematoides Duddingtonia flagrans (AC001) sobre larvas infectantes de ciatostomíneos foi avaliada em condições laboratoriais em ensaio experimental em meio ágar-água 2% (AA 2%). Houve redução significativa (p < 0,01) de 93,64% na média de larvas infectantes de ciatostomíneos recuperadas do meio AA2%, ao final de sete dias. Os resultados desse ensaio evidenciam que o isolado fúngico AC001 poderia ser utilizado no controle biológico de ciatostomíneos de equinos.

The predatory capacity of one isolate of nematode-trapping fungus Duddingtonia flagrans (AC001) on infective larvae of cyathostomes was evaluated in laboratorial conditions in medium water-agar 2% (WA 2%). There was significant reduction (p < 0. 01) of 93.64% in the average of infective larvae of cyathostomes recovered of medium WA 2% at seven day. These results show that the isolated AC001 could be used in the biological control of cyathostomes of horses.

Duddingtonia flagrans: controle biológico de nematodeos de bovinos a campo / Duddingtonia flagrans: biological control of cattle nematodes in the field

O controle biológico é um método para diminuir uma população pela utilização de antagonista natural. No presente estudo, testou-se a eficácia do fungo nematófago Duddingtonia flagrans no controle de nematódeos parasitos gastrintestinais de bovinos criados à campo no município de Júlio de Castilhos. Foram utilizados 20 bezerros, distribuídos igualmente em duas áreas formadas por pastagem nativa. O grupo A foi tratado com o fungo D. flagrans, cultivado em sorgo, numa concentração de 1x10(6)clamidósporos kg-1 de peso animal, misturados em ração de manutenção, diariamente, durante oito meses. O grupo B serviu como controle e não recebeu fungo, apenas ração. Foram coletadas amostras para contagem de ovos por grama de fezes (OPG) semanalmente. Mensalmente, foram realizadas coproculturas para identificar as espécies de larvas de nematódeos, a pesagem dos animais e a coleta de pasto para contagem das larvas na pastagem. Dados de temperatura e índice pluviométrico foram registrados diariamente. O OPG foi reduzido no grupo tratado, em média 56,8, por cento nos últimos três meses de experimento, variando entre 40,4 e 67,1 por cento no grupo tratado (P<0,001). A coprocultura demonstrou que os principais nematódeos encontrados em ambos os grupos foram dos gêneros Cooperia e Haemonchus. A contagem de larvas na pastagem obteve um percentual de redução 77,1 por cento no grupo tratado ao final do experimento (P<0,01). Pôde-se concluir com este estudo que o papel do fungo Duddingtonia flagrans, é, sem dúvida, importante, principalmente, na diminuição do OPG e na redução significativa de larvas na pastagem. Portanto, este fungo nematófago é uma ferramenta biológica eficaz para ser empregado em um controle integrado de nematódeos de bovinos criados a campo.

Biological control is an alternative method to reduce parasite's population by the use of natural antagonist. In the present study, efficacy of nematophagous fungus Duddingtonia flagrans was tested to control gastrointestinal nematodes parasites of cattle livestock in the field. Twenty calves were used, distributed equally in two distinct plots formed by native pasture. Group A was treated with D. flagrans fungus, cultivated in sorghum (1x10(6) clamidospores kg-1 body weight) mixed with maintenance ration, each day, during eight months. Group B served as a control and did not receive the fungus. Samples for faecal egg count (FEC), were collected each week. There were monthly counts in faecal cultures to identify the species of nematodes larvae, animals weight, blood collection to determine red cell counts and collection of pasture to larvae counting. Temperature and rainfall data were registered daily. The FEC reduced around 56.8 percent in the last three months of the experiment, with a variation between 40.4 and 67.1 percent in the treated group (P<0.001). The faecal cultures demonstrated that the main nematodes found in both the groups were Cooperia and Haemonchus. Larvae counting in the pasture showed a reduction percentage around 77.1 percent in treated group at the end of experiment (P<0.01). It could be concluded with this study, that Duddingtonia flagrans has an important role in the reduction of FEC and significant reduction of larvae in the pasture. Therefore, this nematophagous fungus is efficient as a biological tool to be used in an integrated nematodes control of bovine raised in the field.

In vitro interaction of Brazilian strains of the Nematode-trapping fungi Arthrobotrys spp. on Panagrellus sp. and Cooperia punctata

In vitro tests were carried out to verify the activity of 26 Brazilian isolates of predatory fungi of the genus Arthrobotrys on a free-living nematode (Panagrellus sp.) and on infective larvae of Cooperia punctata, a parasitic gastrointestinal nematode of cattle. The results showed that the free-living nematode Panagrellus sp. was the most preyed upon, compared to C. punctata, for all the fungal treatments. Also, variable predatory capacity was observed for different fungal isolates belonging to the same genus when applied to different nematode species

In vitro activity of Brazilian strains of the predatory fungi Arthrobotrys spp. on free-living nematodes and infective larvae of Haemonchus placei

In vitro tests were carried out to assess the activity of 26 Brazilian isolates of predatory fungi of the genus Arthrobotrys on a free-living nematode (Panagrellus sp.) and on infective larvae of Haemonchus placei, a parasitic gastrointestinal nematode of cattle. The results showed that the free-living nematode Panagrellus sp. was the most preyed upon, compared to H. placei, for all the fungal treatments. Also, variable predatory capacity was observed for different fungal isolates belonging to the same genus when applied to different nematode species

Differential in vitro pathogenicity of predatory fungi of the genus Monacrosporium for phytonematodes, free-living nematodes and parasitic nematodes of cattle

In vitro tests were carried out on the pathogenicity of nine isolates of the predatory fungi of the genus Monacrosporium (5 M. sinense isolates, 3 M. appendiculatum and 1 M. thaumasium isolate) for a phytonematode (second stage juveniles from Meloidogyne incognita, race 3), a free-living nematode (Panagrellus spp), and two gastrointestinal parasitic nematodes of cattle (infective larvae of Cooperia punctata and Haemonchus placei). A suspension containing 2,000 nematodes from each species was added to Petri dishes containing fungi and grown on 2 percent water-agar medium at 25oC in the dark for up to 7 days. The dishes were examined every other day for 7 days and predation-free nematodes were counted. The results showed that the free-living nematodes, Panagrellus spp, were the most susceptible (P<0.05), followed by the phytonematode M. incognita, while the controls were 98.5 percent viable. However, a variable susceptibility of the nematodes to different fungi was observed. This indicates that the use of predatory fungi for the environmental control of nematodes will be limited by the multiplicity of nematodes in the environment and their differential susceptibility to fungal isolates of the same genus

Isoenzyme analysis of Arthrobotrys, a nematode-trapping fungus

Extraction and isoenzyme analysis of four isolates of Arthrobotrys including A. musiformis, A. robusta and A. conoides were conducted. Among the 14 enzymes studied by starch gel electrophoresis, using morpholine-citrate as gel/electrode buffer, the following nine enzymes showed interpretable banding patterns: alpha-esterase, fumarase, hexokinase, isocitrate dehydrogenase, leucine aminopeptidase, malate dehydrogenase, 6-phosphogluconate dehydrogenase, phosphoglucomutase and phosphoglucoisomerase. All isolates studied displayed typical isoenzyme phenotypes for each species. Two isolates of A. conoides differed in their alpha-isoesterase banding patterns, but no differences were observed for the other enzymes. The assay was satisfactory for enzyme extraction and resolution of Arthrobotrys and could be used in future taxonomic and genetic studies of this organism.