Formation of Sclerotia and Production of Indoloterpenes by Aspergillus niger and Other Species in Section Nigri

Several species in Aspergillus section Nigri have been reported to produce sclerotia on well-known growth media, such as Czapek yeast autolysate (CYA) agar, with sclerotia considered to be an important prerequisite for sexual development. However Aspergillus niger sensu stricto has not been reported to produce sclerotia, and is thought to be a purely asexual organism. Here we report, for the first time, the production of sclerotia by certain strains of Aspergillus niger when grown on CYA agar with raisins, or on other fruits or on rice. Up to 11 apolar indoloterpenes of the aflavinine type were detected by liquid chromatography and diode array and mass spectrometric detection where sclerotia were formed, including 10,23-dihydro-24,25-dehydroaflavinine. Sclerotium induction can thus be a way of inducing the production of new secondary metabolites from previously silent gene clusters. Cultivation of other species of the black aspergilli showed that raisins induced sclerotium formation by A. brasiliensis, A. floridensis A. ibericus, A. luchuensis, A. neoniger, A. trinidadensis and A. saccharolyticus for the first time

Genetic Variants on Chromosome 1q41 Influence Ocular Axial Length and High Myopia

As one of the leading causes of visual impairment and blindness, myopia poses a significant public health burden in Asia. The primary determinant of myopia is an elongated ocular axial length (AL). Here we report a meta-analysis of three genome-wide association studies on AL conducted in 1,860 Chinese adults, 929 Chinese children, and 2,155 Malay adults. We identified a genetic locus on chromosome 1q41 harboring the zinc-finger 11B pseudogene ZC3H11B showing genome-wide significant association with AL variation (rs4373767, β = −0.16 mm per minor allele, Pmeta = 2.69×10−10). The minor C allele of rs4373767 was also observed to significantly associate with decreased susceptibility to high myopia (per-allele odds ratio (OR) = 0.75, 95% CI: 0.68–0.84, Pmeta = 4.38×10−7) in 1,118 highly myopic cases and 5,433 controls. ZC3H11B and two neighboring genes SLC30A10 and LYPLAL1 were expressed in the human neural retina, retinal pigment epithelium, and sclera. In an experimental myopia mouse model, we observed significant alterations to gene and protein expression in the retina and sclera of the unilateral induced myopic eyes for the murine genes ZC3H11A, SLC30A10, and LYPLAL1. This supports the likely role of genetic variants at chromosome 1q41 in influencing AL variation and high myopia

Investigation of inter- and intraspecies variation through genome sequencing of Aspergillus section Nigri

Aspergillus section Nigri comprises filamentous fungi relevant to biomedicine, bioenergy, health, and biotechnology. To learn more about what genetically sets these species apart, as well as about potential applications in biotechnology and biomedicine, we sequenced 23 genomes de novo, forming a full genome compendium for the section (26 species), as well as 6 Aspergillus niger isolates. This allowed us to quantify both inter-and intraspecies genomic variation. We further predicted 17,903 carbohydrateactive enzymes and 2,717 secondary metabolite gene clusters, which we condensed into 455 distinct families corresponding to compound classes, 49% of which are only found in single species. We performed metabolomics and genetic engineering to correlate genotypes to phenotypes, as demonstrated for the metabolite aurasperone, and by heterologous transfer of citrate production to Aspergillus nidulans. Experimental and computational analyses showed that both secondary metabolism and regulation are key factors that are significant in the delineation of Aspergillus species.Peer reviewe

The genetics of myopia

Myopia is the most common eye condition worldwide and its prevalence is increasing. While changes in environment, such as time spent outdoors, have driven myopia rates, within populations myopia is highly heritable. Genes are estimated to explain up to 80% of the variance in refractive error. Initial attempts to identify myopia genes relied on family studies using linkage analysis or candidate gene approaches with limited progress. More genome-wide association study (GWAS) approaches have taken over, ultimately resulting in the identification of hundreds of genes for refractive error and myopia, providing new insights into its molecular machinery. These studies showed myopia is a complex trait, with many genetic variants of small effect influencing retinal signaling, eye growth and the normal process of emmetropization. The genetic architecture and its molecular mechanisms are still to be clarified and while genetic risk score prediction models are improving, this knowledge must be expanded to have impact on clinical practice

Estimated intake of benzoic and sorbic acids in Denmark

International audienceThe monitoring of food additives and recent dietary surveys carried out in Denmark have earlier been used to estimate the intake of sweeteners and nitrite in relation to ADI values. The ubiquitous use of the preservatives benzoic and sorbic acid raises the question of the magnitude of the intake of these preservatives in relation to ADI values, which is explored in the present investigation. The content of benzoic and sorbic acid in all food groups, where they are allowed, has been monitored in Denmark 17 times from 2001 to 2006 with a total of 1526 samples. Transgressions of maximum limits, illegal use or declaration faults have been found in about 3% of the samples. From repeated investigations on fat based foods (salads and dressings), marmalade and stewed fruit it can be concluded that the amounts used by the industry have been relatively stable through the whole period, although limited data for marmalade show some variation. Most foods in the categories soft drinks, dressing, fat based salads, pickled herrings and marmalade contain benzoic and sorbic acid, and sliced bread contain in some cases also sorbic acid. The median daily intake and intake distribution of benzoic and sorbic acid have been calculated with data from the Danish National Survey of Dietary Habits and Physical Activity (age: 4-75 years) conducted in 2000-04 with 5785 participants.The median intakes of both benzoic acid and sorbic acid are well below the acceptable daily intake (ADI) values of 0-5 mg/kg bw/day and 0-25 mg/kg bw/day for benzoic and sorbic acid respectively. However, the 90th percentile based on the average of the samples with a content of benzoic acid is higher than the ADI value for both men and women with the highest value of 16 mg/kg bw/day for both boys and girls in the age group 4-6 year old.. Based on the average of all the samples the 95th percentile is over the ADI value for men up to 34 years and for women up to 24 years and the 90th percentile for men up to 18 years and for women up to 10 years. Soft drinks, salads and dressing are the main contributors to the benzoic acid intake.The sorbic acid intake based on the average of all samples is well below the ADI value. However, for the intake based on the average of samples with content the 95th percentile exceeds the ADI . This is caused by the dominating contribution to the intake of sorbic acid from sliced bread, but since only 7 out of 42 samples have added sorbic acid, the calculation based on the average of samples with content will exaggerate the intake. With the built in safety factor of 100 in the ADI values and judging from the literature the high intakes of benzoic acid should not cause any concern for ill effects. However, there must be reason to reconsider the maximum limits especially for benzoic acid in soft drinks, dressing and salads and for sorbic acid in sliced bread