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Aspergillus nidulans has long-been used as a model organism to gain insights into the genetic basis of asexual and sexual developmental processes both in other members of the genus Aspergillus, and filamentous fungi in general. Paradigms have been established concerning the regulatory mechanisms of conidial development. However, recent studies have shown considerable genome divergence in the fungal kingdom, questioning the general applicability of findings from Aspergillus, and certain longstanding evolutionary theories have been questioned. The phylogenetic distribution of key regulatory elements of asexual reproduction in A. nidulans was investigated in a broad taxonomic range of fungi. This revealed that some proteins were well conserved in the Pezizomycotina (e.g. AbaA, FlbA, FluG, NsdD, MedA, and some velvet proteins), suggesting similar developmental roles. However, other elements (e.g. BrlA) had a more restricted distribution solely in the Eurotiomycetes, and it appears that the genetic control of sporulation seems to be more complex in the aspergilli than in some other taxonomic groups of the Pezizomycotina. The evolution of the velvet protein family is discussed based on the history of expansion and contraction events in the early divergent fungi. Heterologous expression of the A. nidulans abaA gene in Monascus ruber failed to induce development of complete conidiophores as seen in the aspergilli, but did result in increased conidial production. The absence of many components of the asexual developmental pathway from members of the Saccharomycotina supports the hypothesis that differences in the complexity of their spore formation is due in part to the increased diversity of the sporulation machinery evident in the Pezizomycotina. Investigations were also made into the evolution of sex and sexuality in the aspergilli. MAT loci were identified from the heterothallic Aspergillus (Emericella) heterothallicus and Aspergillus (Neosartorya) fennelliae and the homothallic Aspergillus pseudoglaucus (=Eurotium repens). A consistent architecture of the MAT locus was seen in these and other heterothallic aspergilli whereas much variation was seen in the arrangement of MAT loci in homothallic aspergilli. This suggested that it is most likely that the common ancestor of the aspergilli exhibited a heterothallic breeding system. Finally, the supposed prevalence of asexuality in the aspergilli was examined. Investigations were made using A. clavatus as a representative ‘asexual’ species. It was possible to induce a sexual cycle in A. clavatus given the correct MAT1-1 and MAT1-2 partners and environmental conditions, with recombination confirmed utilising molecular markers. This indicated that sexual reproduction might be possible in many supposedly asexual aspergilli and beyond, providing general insights into the nature of asexuality in fungi.

The initial adhesion of micro‐organisms on solid surfaces strongly affects their transport and fate in soil and aquatic environments. Experiments on Bacillus subtilis with various soil minerals (including kaolinite, montmorillonite, goethite, birnessite, quartz and mica) were conducted to determine the role of surface properties in adhesion and to test the validity of the extended Derjaguin, Landau, Verwey and Overbeek (DLVO) theory for bacterial adhesion. Adhesion of B. subtilis on all six minerals conformed to the Langmuir equation. Adhesion capacity and affinity showed a significant correlation with the specific external surface area (SESA) of the minerals and the calculated electrostatic energy barrier, respectively, but no significant correlation was observed between hydrophobicity and the adhesion parameters. These results demonstrate that adhesion capacity and affinity are primarily controlled by the SESA of the minerals and the surface electrical properties, respectively. The dependence of the adhesion capacity on SESA may be explained by the cell–mineral interaction model. Adhesion could be well predicted by the extended DLVO theory. The initial adhesion of bacteria with soil minerals can be evaluated by using independently measured surface properties of these components based on the extended DLVO theory combined with the Langmuir equation.

1. We hypothesise that administration of available glutamine and carbohydrates by in ovo injection may provide energy for small intestine and duck embryo activity, in turn alleviating energy lack, sparing the pectoralis muscle protein and increasing breast muscle mass. To test this hypothesis, 220 duck eggs at 21 d of incubation were chosen and assigned to two treatments. At 23 d of incubation, glutamine, digestible sucrose and maltose were injected into the amniotic fluid in the treatment group. 2. In ovo injection of glutamine and carbohydrates improved small intestine development, as reflected in the increase in weight and sucrase activity, though gizzard, proventriculus and liver weight were not affected by the in ovo injection. 3. Compared with control, pectoralis weight in treatment ducks was increased by 24% at 25 d of incubation and 15% at hatch and this advantage was sustained until 7 d posthatch. In ovo injection improved duck weight gain in the early days posthatch. 4. The results of the present study suggest that in ovo injection of glutamine and carbohydrates improves small intestine development and pectoralis mass, which is probably due to sparing of breast muscle protein.

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