In vitro effect of pesticides on the germination, vegetative growth, and conidial production of two strains of Metarhizium anisopliae

Entomopathogenic fungi are widely used as biological control agents against a broad range of insect and arachnid pests. However, the control efficacy of entomopathogenic fungi is variable because of unfavourable and fluctuating environmental conditions and intrinsic factors. One strategy to enhance entomopathogenic fungi efficacy is a combined use of entomopathogenic fungi and low dosages of pesticides. These sub-lethal dosages of chemicals can increase the control efficiency of entomopathogenic fungi but only if they do not affect the fungi. Adverse effects could include the inhibition of germination and/or vegetative growth as well as conidiogenesis. The present study investigated the in vitro effects of different concentrations of fipronil, permethrin, imidacloprid, NeemAzal, and amitraz as potential candidates for combined applications on two strains of the entomopathogenic fungus Metarhizium anisopliae (MA). MA was inoculated on a medium amended with five different concentrations (0.32-200 ppm) of the abovementioned pesticides. The germination, vegetative growth, and sporulation were evaluated. The results showed, according to a physiology parameter compatibility classification, that all pesticides were compatible with both tested MA strains. Only fipronil in the higher dose rates of 40 and 200 ppm was close to moderately toxic to MA-7. Furthermore, only higher concentrations of the pesticides caused a slight inhibition (about 15%) of conidial germination and a reduction in colony size. Sporulation was reduced at most by approximately 50% by 40 or 200 ppm of fipronil or amitraz, respectively. Therefore, it is possible to use the tested pesticides in combination with either strain of MA for an integrated pest management approach. Studies on the effect of these combinations on target organisms are in progress.     

Maintenance of paternal methylation and repression of the imprinted H19 gene requires MBD3

Paternal repression of the imprinted H19 gene is mediated by a differentially methylated domain (DMD) that is essential to imprinting of both H19 and the linked and oppositely imprinted Igf2 gene. The mechanisms by which paternal-specific methylation of the DMD survive the period of genome-wide demethylation in the early embryo and are subsequently used to govern imprinted expression are not known. Methyl-CpG binding (MBD) proteins are likely candidates to explain how these DMDs are recognized to silence the locus, because they preferentially bind methylated DNA and recruit repression complexes with histone deacetylase activity. MBD RNA and protein are found in preimplantation embryos, and chromatin immunoprecipitation shows that MBD3 is bound to the H19 DMD. To test a role for MBDs in imprinting, two independent RNAi-based strategies were used to deplete MBD3 in early mouse embryos, with the same results. In RNAi-treated blastocysts, paternal H19 expression was activated, supporting the hypothesis that MBD3, which is also a member of the Mi-2/NuRD complex, is required to repress the paternal H19 allele. RNAi-treated blastocysts also have reduced levels of the Mi-2/NuRD complex protein MTA-2, which suggests a role for the Mi-2/NuRD repressive complex in paternal-specific silencing at the H19 locus. Furthermore, DNA methylation was reduced at the H19 DMD when MBD3 protein was depleted. In contrast, expression and DNA methylation were not disrupted in preimplantation embryos for other imprinted genes. These results demonstrate new roles for MBD3 in maintaining imprinting control region DNA methylation and silencing the paternal H19 allele. Finally, MBD3-depleted preimplantation embryos have reduced cell numbers, suggesting a role for MBD3 in cell division.     

The H50Q Mutation Induces a 10-fold Decrease in the Solubility of α-Synuclein

The conversion of α-synuclein from its intrinsically disordered monomeric state into the fibrillar cross-β aggregates characteristically present in Lewy bodies is largely unknown. The investigation of α-synuclein variants causative of familial forms of Parkinson disease can provide unique insights into the conditions that promote or inhibit aggregate formation. It has been shown recently that a newly identified pathogenic mutation of α-synuclein, H50Q, aggregates faster than the wild-type. We investigate here its aggregation propensity by using a sequence-based prediction algorithm, NMR chemical shift analysis of secondary structure populations in the monomeric state, and determination of thermodynamic stability of the fibrils. Our data show that the H50Q mutation induces only a small increment in polyproline II structure around the site of the mutation and a slight increase in the overall aggregation propensity. We also find, however, that the H50Q mutation strongly stabilizes α-synuclein fibrils by 5.0 ± 1.0 kJ mol⁻¹, thus increasing the supersaturation of monomeric α-synuclein within the cell, and strongly favors its aggregation process. We further show that wild-type α-synuclein can decelerate the aggregation kinetics of the H50Q variant in a dose-dependent manner when coaggregating with it. These last findings suggest that the precise balance of α-synuclein synthesized from the wild-type and mutant alleles may influence the natural history and heterogeneous clinical phenotype of Parkinson disease.     

Sulla presunta azione fungicida dello juglone

Summary

Having experimented the juglone in its antibiotic action it has been seen that such an action manifests itself very weackly towards the Schizomycetes. No action it acts towards yeasts, and mycelium fungi including phytopatogenus fungi (against what has been adfirmed by others precedently).     

AFLP markers and cytotaxonomic analysis reveal hybridisation in the genus Schoenus (Cyperaceae).

Molecular, cytological, and morphological data support the existence of a hybrid population between Schoenus nigricans and Schoenus ferrugineus. This population was found in northeastern Italy, where S. nigricans is central with respect to its natural range and S. ferrugineus is marginal, being most common in the Alps and in central and northern Europe. Molecular marker data show that the putative hybrid population is genetically intermediate between nearby populations of the parent species. Cytological evidence confirmed the hybrid nature of this population, as does the almost complete sterility of plants within the population. Although no seeds were produced by the hybrid population, some possibly fertile pollen grains were produced; this suggests that the possibility of introgression between the two species through the hybrids cannot completely be excluded.     

Studio microbiologico di un terreno torboso

Zusammenfassung Es wurde ein oberitalienischer Moorboden aus dem Po-Tal mikrobiologisch untersucht. Die Keimzahl ist sehr niedrig; es handelt sich im wesentlichen um Pilze. Ammoniakbildungs- und Stickstoffbindungs-vermögen sind gering, das Nitrifikationsvermögen ist fast Null. Denitrifikations- und CO₂-Bildungsvermögen sind dagegen hoch.