Studies on optimization of nitrogen sources for astaxanthin production by Phaffia rhodozyma

Fermentation of Phaffia rhodozyma is a major method for producing astaxanthin, an important pigment with industrial and pharmaceutical application. To improve astaxanthin productivity, single factor and mixture design experiments were used to investigate the effects of nitrogen source on Phaffia rhodozyma cultivation and astaxanthin production. Results of single factor experiments showed nitrogen source could significantly affect P. rhodozyma cultivation with respect to carbon source utilization, yeast growth and astaxanthin accumulation. Further studies of mixture design experiments using (NH(4))(2)SO(4), KNO(3) and beef extract as nitrogen sources indicated that the proportion of three nitrogen sources was very important to astaxanthin production. Validation experiments showed that the optimal nitrogen source was composed of 0.28 g/L (NH(4))(2)SO(4), 0.49 g/L KNO(3) and 1.19 g/L beef extract. The kinetic characteristics of batch cultivation were investigated in a 5-L pH-stat fermentor. The maximum amount of biomass and highest astaxanthin yield in terms of volume and in terms of biomass were 7.71 mg/L and 1.00 mg/g, respectively.

Observação in vitro da ação dos isolados fúngicos Duddingtonia flagrans, Monacrosporium thaumasium e Verticillium chlamydosporium sobre ovos de Ascaris lumbricoides (Lineu, 1758)

Observou-se a ação in vitro dos fungos nematófagos Duddingtonia flagrans, Monacrosporium thaumasium e Verticillium chlamydosporium sobre ovos de Ascaris lumbricoides. Após sete, dez e quatorze dias de interação, o fungo promissor a ser utilizado no controle biológico de Asaris lumbricoides foi o Verticillium chlamydosporium (26-30%). Os outros fungos não foram satisfatórios.

Cross-induction of systemic induced resistance between an insect and a fungal pathogen in Austrian pine over a fertility gradient

Evidence for cross-induction of systemic resistance or susceptibility in plant-fungus-herbivore interactions is mostly derived from herbaceous model systems and not perennial woody plants. Furthermore, the effects of environmental variables such as soil fertility on these tripartite interactions are generally unknown. This study examined cross-induction of systemic resistance in Pinus nigra (Austrian pine) to infection by Sphaeropsis sapinea (a fungal pathogen), or feeding by Neodiprion sertifer (European pine sawfly), by prior induction with either S. sapinea or N. sertifer, over a fertility gradient. In a replicated 3-year study, cross-induction of systemic induced resistance (SIR) was found to be both asymmetric within a single year and variable between years. Prior induction with insect defoliation induced SIR to subsequent fungal challenge in 2006 but not in 2005. In 2005, a fertility-independent negative systemic effect of the fungal infection on herbivore growth was detected while herbivore survival was affected by a significant interaction between induction treatment and fertility level in 2006. Prior infection by the fungus induced SIR against the same fungus in both years regardless of fertility levels. This is the first report of whole-plant SIR against a defoliating insect induced by a fungal pathogen and vice versa, under variable nutrient availability, in a conifer or any other tree.

Decoding the mannitol enigma in filamentous fungi

Mannitol is a 6-carbon polyol that is among the most abundant biochemical compounds in the biosphere. Mannitol has been ascribed a multitude of roles in filamentous fungi including carbohydrate storage, reservoir of reducing power, stress tolerance and spore dislodgement and/or dispersal. The advancement of genetic manipulation techniques in filamentous fungi has rapidly accelerated our understanding of the roles and metabolism of mannitol. The targeted deletion of genes encoding proteins of mannitol metabolism in several fungi, including phytopathogens, has proven that the metabolism of mannitol does not exist as a cycle and that many of the postulated roles are unsupported. These recent studies have provided a much needed focus on this mysterious metabolite and make this a fitting time to review the roles and metabolism of mannitol in filamentous fungi.

The ecology of nematode-trapping hyphomycetes in cattle dung from three plateau pastures

This paper investigated the influence of season and altitude on the occurrence of nematode-trapping fungi in cattle faeces. Six hundred and sixty samples of cattle faeces deposited on three plateau pastures with different altitudes in the west of Yunnan Province, China, were examined in 2004. A total of 17 species of nematode-trapping hyphomycetes were isolated from these samples. The predominant species from all three plateau pastures were Arthrobotrys oligospora, A. musiformis, Monacrosporium ellipsosporum, and M. thaumasium. Species with adhesive networks were the most frequently isolated. Overall, species diversity index was negatively correlated with altitude and was different among seasons within the same site. Levels of diversity were highest in the summer, followed by autumn, spring, and winter. The conidia of the hyphomycetes isolated here germinated normally on medium containing cattle faeces, with species developing adhesive networks having the highest rate of germination. However, the rate of conidial trap (CT) formation was lower in species with adhesive networks than those in other species.

Hongos nematófagos de huevos de Toxocara canis en un paseo público de La Plata, Argentina

Fungi have showed a great potential for the biological control of nematodes. However, they have not been evaluated for the control of animal and/or human parasites transmitted by egg contaminated soils. Environmental contamination with Toxocara spp. eggs is a public health problem. Accidental swallowing of Toxocara canis eggs (a nematode of dogs) usually results on a zoonotic infection (toxocarosis). The objectives of this research were: 1) To test the presence of antagonistic fungi against T. canis in the soil in public places of La Plata city, Argentina, infected with eggs of this parasite, 2) To determine the possible association between biotic and abiotic factors of the soil with the presence of fungal parasites of egg nematodes. Soil samples were tested for: textural type, organic matter (%), pH, presence of egg-parasite fungi, of larvae and of nematode eggs, in particular of Toxocara spp. The studied area showed the following characteristics: pH: 6.6-8.0, organic matter: 1.2-70%, with a predominantly loam texture. The following antagonistic fungal genera were identified: Acremonium, Aspergillus, Chrysosporium, Fusarium, Humicola, Mortierella, Paecilomyces and Penicillium. A prevalence of 70% was detected for nematode eggs, of 33% for Toxocara spp. eggs and of 90% for larvae. No association between the presence of egg-parasite fungi and the considered factors was found. More studies are necessary to know the natural antagonism factors to T. canis eggs for its in situ biological control.

The first fifty microarray studies in filamentous fungi

Microarray studies have examined global gene expression in over 20 species of filamentous fungi encompassing a wide variety of research areas. The majority have addressed aspects of metabolism or pathogenicity. Metabolic studies have revealed important differences in the transcriptional regulation of genes for primary metabolic pathways between filamentous fungi and yeast. Transcriptional profiles for genes involved in secondary metabolism have also been established. Genes required for the biosynthesis of both useful and detrimental secondary metabolites have been identified. Due to the economic, ecological and medical implications, it is not surprising that many studies have used microarray analysis to examine gene expression in pathogenic filamentous fungi. Genes involved in various stages of pathogenicity have been identified, including those thought to be important for adaptation to the host environment. While most of the studies have simulated pathogenic conditions in vitro, a small number have also reported fungal gene expression within their plant hosts. This review summarizes the first 50 microarray studies in filamentous fungi and highlights areas for future investigation.

Duration and spread of an entomopathogenic fungus, Beauveria bassiana (Deuteromycota: Hyphomycetes), used to treat varroa mites (Acari: Varroidae) in honey bee (Hymenoptera: Apidae) hives

A strain of the fungus Beauveria bassiana (Balsamo) Vuillemin (Deuteromycota: Hyphomycetes) isolated from varroa mites, Varroa destructor Anderson & Trueman (Acari: Varroidae), was used to treat honey bees, Apis mellifera L. (Hymenoptera: Apidae), against varroa mites in southern France. Fungal treatment caused a significant increase in the percentage of infected varroa mites compared with control treatments in two field experiments. In the first experiment, hives were treated with a formulation containing 0.37 g of B. bassiana conidia per hive and in the second experiment with a dose of 1.0 g of conidia per hive. The percentage of infected varroa mites also increased in the nontreated (control) hives, suggesting a movement of conidia, probably via bee drift, among the hives. Mite fall was significantly higher among treated hives compared with control hives on the sixth and eighth days after treatment in the first experiment. These days correspond to previously published data on the median survivorship of mites exposed to that fungal solate. The interaction of treatment and date was significant in the second experiment with respect to mite fall. Increases in colony-forming unit (cfu) density per bee were observed in all treatments but were significantly higher among bees from treated hives than control hives for at least a week after treatment. The relationship between cfu density per bee and proportion infected was modeled using a sigmoid curve. High levels of infection (>80%) were observed for cfu density per bee as low as 5 x 102 per bee, but the cfu density in hives treated with 0.37 g generally dropped below this level less than a week after treatment.

Maturation feeding and transmission of Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae) by Monochamus alternatus (Coleoptera: Cerambycidae) inoculated with Beauveria bassiana (Deuteromycotina: Hyphomycetes)

We examined the amount of maturation feeding and transmission of pinewood nematodes, Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle (Nematoda: Parasitaphelenchidae), to healthy pine (Pinus spp.) trees by pine sawyer Monochamus alternatus Hope (Coleoptera: Cerambycidae) adults infected with Beauveria bassiana (Balsamo) Vuill. (Deuteromycotina: Hyphomycetes). Inoculated beetles fed less than noninoculated beetles, probably because feeding by inoculated beetles began to decrease at about 4 d postinoculation and inoculated beetles ceased to feed for several days before their death. In inoculated beetles carrying >1,000 nematodes, some beetles died before nematode departure. The remaining heavily nematode-infested beetles lived until the beginning of nematode departure, but they had stopped feeding, preventing the nematodes from entering pine twigs. We suggest that microbial control of pine sawyer adults by B. bassiana may be effective in preventing transmission of pine wilt disease to healthy pine trees.

Utilization of various carbon sources for the growth of waterborne conidial fungi

Four isolates of waterborne conidial fungi (Tetracheatum elegans, Tetracladium marchalianum, Pestalotiopsis submersus and Flagellospora penicillioides) were investigated for their carbon requirement, using eight different carbon sources (viz. glucose, fructose, sucrose, xylose, starch, cellulose, dextrin and lactose). All fungi tested grew sparsely on the basal medium lacking in carbon, which was the control. However these fungi were found to vary in their ability to use the supplied sources of carbon. Glucose and sucrose were found to be suitable sources of carbon for all four fungal isolates, whereas fructose proved good for T. marchalianum and P. submersus. Starch and xylose also supported growth of T. marchalianum, P. submersus and F. penicillioides. Cellulose, a polysaccharide, was a poor source of carbon for the growth of these isolates. Four g/L of glucose was recorded as the most useful concentration that gives the maximum dry weight of selected fungi (262 mg and 400 mg for T. elegans and P. submersus respectively after 15 d).

Pathogenicity of entomopathogenic fungi on hibernating pupae of Cameraria ohridella Deschka & Dimic 1986 (Lepidoptera, Gracillariidae). Part 2: Efficacy of entomopathogenic fungi against pupa in her pupal cell

The naked pupae of chestnut leafminer Cameraria ohridella are susceptible for entomopathogenic fungi Paecilomyces fumosoroseus strain P6; Lecanicillium muscarium strain V24; Metarhizium anisopliae strain M72 and Beauveria bassiana strain B412. Their activity at low temperature is advantageous especially for the use in the winter season. (Richter et al., 2007a). Therefore the possibility of infection should be examined in biotest for pupae in their pupal cells on leaf of chestnut at conditions Like in winter. Efficacy of entomopathogenic fungi is decreased, if pupae are in their pupal cells. But fungi, especially L. muscarium, proved the ability to infect pupae of C. ohridella in their pupal cells. Infected pupae moulded in their pupal cells after application. Infection doesn't come from spores. In semi field trials with L. muscarium 60% of pupae were infected in their pupal cells and died after incubation with mouldiness.

Pathogenicity of entomopathogenic fungi on hibernating pupae of Cameraria ohridella Deschka & Dimic 1986 (Lepidoptera, Gracillariidae). Part 1: Pathogenicity against the naked pupa

Strains from Paecilomyces fumosoroseus, Lecanicillium muscarium, Metarhizium anisopliae and Beauveria bassiana were examined in standardized Biotest to control the horse-chestnut leaf miner (Cameraria ohridella) in her pupal stage in winter. The fungi were pathogenic against the hibernating pupae of Cameraria ohridella at dose of 1.9 x 10(7) conidia/ml. They were aggressive, led to infection, death and mouldiness of naked pupae. Even at low temperature of 5 degrees C and 12 degrees C. L. muscarium strain V24 showed the highest pathogenicity after 4 weeks against this host, close followed by P. fumosoroseus strain P6. M. anisopliae strain 72 and 8. bassiana strain B412 were also pathogen but after a long-time period. Experiments gave information for general susceptibility of naked pupae of C. ohridella under low temperatures against entomopathogenic fungi. In further examinations it has to be tested, whether fungi can infected, when the pupae stay in their natural surroundings, the pupal cell in the leaf.

Influence of conidial traits and leaf structure on attachment success of aquatic hyphomycetes on leaf litter

Attachment of conidia on leaves is a critical first step in the life cycle of aquatic hyphomycetes in streams. In a first series of microcosm experiments, attachment success of three common aquatic hyphomycete species differing in conidial shape (compact, filiform and tetraradiate) was determined on two leaf species, black alder and downy oak. Fungal species identity and leaf surface structure significantly affected conidial attachment after 24 h. The lower sides of oak leaves with extensive tufts trapped 2.4-8.8 more conidia than the upper sides of oak leaves and both sides of alder leaves. In a second experiment with seven fungal species, attachment success of two species with tetraradiate conidia was much greater than that of two other tetraradiate and three compact conidia, which all had similar attachment success. The species with the largest spores was also the most successful, but this pattern was not consistent across the size range of tested conidia. These results highlight the importance of leaf surface structure, possibly conidial shape and size and additional properties of aquatic hyphomycete conidia in determining attachment success on leaves and they point to the potential role of these factors in structuring fungal communities on decomposing leaves in streams.

Streams in Quebec boreal and mixed-wood forests reveal a new aquatic hyphomycete species, Dwayaangam colodena sp. nov

Foam from eight streams in boreal and mixed-wood forests in Québec were sampled in early and late fall 2002 to evaluate the biodiversity of their aquatic hyphomycete communities. Two regions were studied: 53-54 degrees N and 46-49 degrees N. A total of 54 species were identified. Twenty taxa were found only in the northern region, and four were unique to the southern region. A new aquatic hyphomycete, Dwayaangam colodena sp. nov., was found mostly in northern streams. It is described along with its taxonomic position.

Effects of carbon concentration and carbon to nitrogen ratio on the growth and sporulation of several biocontrol fungi

Effects of carbon concentration and carbon to nitrogen (C:N) ratio on six biocontrol fungal strains are reported in this paper. All fungal strains had extensive growth on the media supplemented with 6-12 gl(-1) carbon and C:N ratios from 10:1 to 80:1, and differed in nutrient requirements for sporulation. Except for the two strains of Paecilomyces lilacinus, all selected fungi attained the highest spore yields at a C:N ratio of 160:1 when the carbon concentration was 12 gl(-1) for Metarhizium anisopliae SQZ-1-21, 6 gl(-1) for M. anisopliae RS-4-1 and Trichoderma viride TV-1, and 8 gl(-1) for Lecanicillium lecanii CA-1-G. The optimal conditions for P. lilacinus sporulation were 8 gl(-1) carbon with a C:N ratio of 10:1 for M-14 and 12 gl(-1) carbon with a C:N ratio of 20:1 for IPC-P, respectively. The results indicated that the influence of carbon concentration and C:N ratio on fungal growth and sporulation is strain dependent; therefore, consideration for the complexity of nutrient requirements is essential for improving yields of fungal biocontrol agents.

Sexual reproduction and the evolution of microbial pathogens

Three common systemic human fungal pathogens--Cryptococcus neoformans, Candida albicans and Aspergillus fumigatus--have retained all the machinery to engage in sexual reproduction, and yet their populations are often clonal with limited evidence for recombination. Striking parallels have emerged with four protozoan parasites that infect humans: Toxoplasma gondii, Trypanosoma brucei, Trypanosoma cruzi and Plasmodium falciparum. Limiting sexual reproduction appears to be a common virulence strategy, enabling generation of clonal populations well adapted to host and environmental niches, yet retaining the ability to engage in sexual or parasexual reproduction and respond to selective pressure. Continued investigation of the sexual nature of microbial pathogens should facilitate both laboratory investigation and an understanding of the complex interplay between pathogens, hosts, vectors, and their environments.

Field study on the survival, migration and overwintering of infective larvae of horse strongyles on pasture in central Ukraine

Experimental studies on the survival of infective stage larvae of horse strongyles and their ability to overwinter on pasture were carried out in central Ukraine (Poltavska oblast). Faecal pats (1.5 kg each) of naturally infected horses were placed on pasture, and samples of faeces and surrounding vegetation (10 g each) were collected each month, excluding the winter months, from November 2002 until April 2004. The number of infective third stage larvae was calculated in each sample and compared with that from the control faecal samples cultivated in the laboratory. In the control samples, the ratio of infective third stage larvae to the initial number of eggs was from 54.7% in June up to 84.2% in November. This ratio depended on the presence of nematophagous fungi growing in the faeces. On pasture, the development of larvae to the infective third stage took approximately 4 weeks in the warm season, from April until September. In October, a percentage of the eggs (25% to EPG value) did not hatch. No larval development was observed in faeces in November. A minute quantity of larvae, about 0.03% of their initial number, was observed to survive on pasture for the 12 months. Migration of infective larvae from the faeces to vegetation was not intensive, between 71% and 89% of larvae remained in the faeces 4 weeks after deposition of the faecal pats, the percentage related to soil humidity in each month. The proportion of larvae successfully surviving during winter appeared to be maximal in faecal pats deposited on pasture in September of the previous year (up to 42.0% of the initial number of larvae). Some larvae were observed surviving winter in soil beneath the faecal pats. The results of the study demonstrated that horse pastures in the central part of Ukraine are never free from the infective third stage larvae of strongyles.

Fungi in the hyporheic zone of a springbrook

Eight bimonthly sediment core samples (n = 6) were collected, to a depth of 64 cm, from the hyporheic zone of a springbrook in southern Ontario, Canada. Sediment cores were divided into three to four sections, and organic matter was subdivided into six different categories. Twigs were the most common substrate, followed by roots, cedar leaves, wood, grass, and deciduous leaves. The contributions of deciduous and cedar leaves declined with depth, whereas that of wood increased. On each sampling date and from each section, three randomly chosen substrates >3 cm were examined for conidia of aquatic hyphomycetes. The number of identified species significantly decreased with depth, and was highest on deciduous leaves and lowest on wood. Season had no significant effect on species numbers. DNA from substrates was extracted, amplified with fungal primers, and differentiated into phylotypes with denaturing gradient gel electrophoresis (DGGE). Absence/presence patterns of phylotype were significantly affected by season but not by section level. Both season and section level significantly affected relative densities of the bands of the 10 most common phylotypes. Our data suggest that aquatic hyphomycetes and other fungi readily disperse within the hyporheic zone, and that their relative scarcity in this habitat is due to a lack of suitable substrates.

Susceptibility of the ant-cultivated fungus Leucoagaricus gongylophorus (Agaricales: Basidiomycota) towards microfungi

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.

Morphological and ecological similarities: wood-boring beetles associated with novel xylose-fermenting yeasts, Spathaspora passalidarum gen. sp. nov. and Candida jeffriesii sp. nov

Ascomycete yeasts that both ferment and assimilate xylose were reported previously as associates of insects living in woody substrates. Most notable have been reports of Pichia stipitis-like yeasts that are widely associated with the wood-boring beetle, Odontotaenius disjunctus (Coleoptera: Passalidae), in the eastern United States. Our continuing investigation of insect gut yeasts has lead to the discovery of two new xylose-fermenting yeasts that phylogenetic analysis places as sister taxa. The beetle hosts, O. disjunctus and Phrenapates bennetti (Coleoptera: Tenebrionidae), are similar in habitat and appearance, and the presence of similar gut yeasts is an additional common feature between them. Here we describe the new yeast genus Spathaspora, the type species S. passalidarum, and its sister taxon Candida jeffriesii and discuss their natural history, including a comparison with Pichia stipitis, another member of a guild of xylose-fermenting yeasts with similar metabolic traits. In addition a morphologically distinct yeast ascospore type is described for Spathaspora.

Efficiency of Duddingtonia flagrans against Trichostrongyle infections of sheep on mountain pastures

The control of sheep nematode parasites in extensive mountain/transhumant management systems using the nematophagous fungus Duddingtonia flagrans was assessed in this study. Two groups of Churra Tensina ewes were allowed to graze for 8 weeks in autumn on two separate paddocks of infected pasture near their winter sheds in the valley. At lambing, ewes and their twin lambs were turned out into the same paddocks for the following 12 weeks. One group of ewes received a daily dose of 5 x 10(5) chlamydospores of Duddingtonia flagrans/kg live weight per day both in autumn and in spring, while the other group was used as a non-treated control. Daily dosing of grazing ewes with the fungus D. flagrans had a clear effect on reducing autumn pasture contamination. This had a subsequent effect on the over-wintering larvae population that was confirmed by a 20% lower worm burden of tracer lambs kept in early spring on the paddock previously grazed by fungus treated ewes. In spring, pasture contamination was also significantly reduced in the paddock grazed by fungi-treated ewes and their lambs showed a 61% lower worm burden and a better performance than the control lambs. Results herein show that fungal spores fed to sheep at critical times with regard to the epidemiology of parasite infection, can have a significant effect on the infective larvae present on pasture, which could further improve lambs performance. This novel approach to parasite control would be of interest amongst both organic and conventional sheep farmers operating in mountain regions.

The impact of daily Duddingtonia flagrans application to lactating ewes on gastrointestinal nematodes infections in their lambs in the Netherlands

Two experiments were performed in 2002 and 2003 to evaluate the effect of biological control of gastrointestinal nematodes in sheep through the daily feeding of 500,000 chlamydospores of Duddingtonia flagrans/kg bodyweight to lactating ewes during the first 9 weeks with their young lambs on pasture. In both experiments four groups of eight ewes and their April-borne lambs were used. They were turned out on four separate plots (plots A) at the beginning of May, moved to similar separate plots after 3 (plots B) and 6 weeks (plots C), respectively, and weaning occurred after 9 weeks. In both experiments, two groups were fed spores daily while the two other groups served as controls. The effect of D. flagrans application was evaluated through faecal egg counts of ewes and lambs, the yield of faecal cultures in ewes, pasture larval counts and worm counts of lambs and tracer lambs. The results demonstrated no effect of D. flagrans application during the first 5 (2002) or 4 (2003) weeks. Subsequently, fungus application strongly reduced the yield in faecal cultures of the ewes. This was, however, not reflected in the pasture larval counts, but lower worm burdens were observed in tracer lambs of 'treated' plots C in 2002 than on those of 'control' plots. In 2003 worm burdens in 'treated' lambs returned to plots B were lower than those of 'control' lambs and a tendency for the same was observed for plots C. However, in all groups, lambs and tracer lambs developed severe haemonchosis.

Biological Control of Gastrointestinal Parasitic Nematodes UsingDuddingtonia flagransin Sheep under Natural Conditions in Mexico

This investigation was aimed to evaluate the use of an oral bio-preparation containing Duddingtonia flagrans chlamydospores for the control of sheep gastrointestinal parasitic nematodes under the Mexican cold high plateau conditions. Two groups of gastrointestinal parasitic nematode naturally infected sheep, were randomly selected and located into two free-gastrointestinal nematode larvae paddocks. Group 1 received once a week a supplement containing D. flagrans chlamydospores mixed with oats and molasses. Group 2 received a similar supplement without any fungal material. After 5 months grazing animals were discarded from the experiment and two groups of free-nematode "tracer" sheep were located into the same paddocks to collect larvae from the contaminated pastures. Animals were slaughtered and necropsied and the nematodes were obtained and counted. A screening of the number of gastrointestinal nematode larvae present on the grass was performed and compared between the two grazing areas. The results showed 56% reduction in the Ostertagia (Teladorsagia) circumcincta and 94% reduction in the Nematodirus sp. population of the "tracer" sheep who grazed on the D. flagrans-treated sheep area, compared to the nematode population in animals grazed on the non-treated area. The results of the number of larvae on the grazing pastures showed a 51.1% reduction for H. contortus, and 100% for Cooperia sp. in the area with fungi. In the case of Trichostrongylus sp. no reduction was observed, when compared to the control group.

Yeast and filamentous fungi as model organisms in microbody research

Yeast and filamentous fungi are important model organisms in microbody research. The value of these organisms as models for higher eukaryotes is underscored by the observation that the principles of various aspects of microbody biology are strongly conserved from lower to higher eukaryotes. This has allowed to resolve various peroxisome-related functions, including peroxisome biogenesis disorders in man. This paper summarizes the major advances in microbody research using fungal systems and specifies specific properties and advantages/disadvantages of the major model organisms currently in use.

Fungi and actinomycetes associated with Meloidogyne spp. eggs and females in China and their biocontrol potential

A survey was conducted to determine the microflora on eggs and females of Meloidogyne spp. collected from plant roots and infested soil in China. A total of 455 fungal isolates belonging to 24 genera and 52 isolates of actinomycetes were obtained from 28 samples from greenhouses and fields in Hainan, Yunnan, Fujian, Hebei, Shandong, and Beijing. The predominant fungal species were Paecilomyces lilacinus (49.3% of the isolates), Fusarium spp. (7.9%), Pochonia chlamydosporia (6.9%), Penicillium spp. (5.7%), Aspergillus spp. (3.2%), and Acremonium spp. (2.8%). Actinomycetes were frequently encountered (10.3%) as well. A total of 350 isolates of nematophagous fungi and actinomycetes were evaluated for their parasitism of eggs and effects on egg hatch and juvenile mortality in vitro. Pathogenicity varied among isolates, and 29.1% of isolates parasitized over 90% eggs 4 days after inoculation. Results also show that seven isolates of fungi and actinomycetes reduced egg hatch rates to less than 10% contrasted to the control of 65.8%, and three isolates killed all hatched juveniles after 7 days. Seventeen fungal isolates and four actinomycete isolates with high pathogenicity in vitro were selected to test biocontrol efficacy in the greenhouse. They reduced tomato root gall index by 13.4-58.9% compared to the no treatment control.