RIKILT voor veilig voedsel

Brochure over de activiteiten van RIKILT, Instituut voor Voedselveiligheid

The Transcriptional Repressor TupA in Aspergillus niger Is Involved in Controlling Gene Expression Related to Cell Wall Biosynthesis, Development, and Nitrogen Source Availability.

The Tup1-Cyc8 (Ssn6) complex is a well characterized and conserved general transcriptional repressor complex in eukaryotic cells. Here, we report the identification of the Tup1 (TupA) homolog in the filamentous fungus Aspergillus niger in a genetic screen for mutants with a constitutive expression of the agsA gene. The agsA gene encodes a putative alpha-glucan synthase, which is induced in response to cell wall stress in A. niger. Apart from the constitutive expression of agsA, the selected mutant was also found to produce an unknown pigment at high temperatures. Complementation analysis with a genomic library showed that the tupA gene could complement the phenotypes of the mutant. Screening of a collection of 240 mutants with constitutive expression of agsA identified sixteen additional pigment-secreting mutants, which were all mutated in the tupA gene. The phenotypes of the tupA mutants were very similar to the phenotypes of a tupA deletion strain. Further analysis of the tupA-17 mutant and the DeltatupA mutant revealed that TupA is also required for normal growth and morphogenesis. The production of the pigment at 37 degrees C is nitrogen source-dependent and repressed by ammonium. Genome-wide expression analysis of the tupA mutant during exponential growth revealed derepression of a large group of diverse genes, including genes related to development and cell wall biosynthesis, and also protease-encoding genes that are normally repressed by ammonium. Comparison of the transcriptome of up-regulated genes in the tupA mutant showed limited overlap with the transcriptome of caspofungin-induced cell wall stress-related genes, suggesting that TupA is not a general suppressor of cell wall stress-induced genes. We propose that TupA is an important repressor of genes related to development and nitrogen metabolism

Successful treatment of stellate multiform amelanotic choroidopathy with photodynamic therapy: A case report

Purpose: To report a case of stellate multiform amelanotic choroidopathy (SMACH) with focal hyperfluorescence on indocyanine green angiography (ICGA), successfully treated with photodynamic therapy (PDT). Observations: An 18-year-old male presented with subretinal fluid (SRF) overlying an irregular lesion in the inner choroid. A diagnosis of probable idiopathic macular neovascularization was made; treatment with intravitreal injections (IVIs) of anti-vascular endothelial growth factor (VEGF) agents showed no effect. The diagnosis was later revised to SMACH due to distinctive features on optical coherence tomography (OCT) and ICGA. Typically, no focal leakage is observed on ICGA in SMACH, and no successful treatment has been previously described. However, our case presented with focal leakage on ICGA, and treatment with full-dose PDT led to complete resolution of SRF. Conclusions and importance: Diagnosing and treating SMACH can be challenging. No effective treatment has been reported to date. We describe a case with focal leakage on ICGA successfully treated with full-dose PDT. We suggest full-dose PDT as the first-line treatment of SMACH with associated focal leakage on ICGA

Signaleringsoverleg Voedselveiligheid : jaarrapportage 2021

Mensen kunnen ziek worden van bacteriën, virussen, of chemische stoffen in voedsel. Om nieuwe risico’s van bacteriën, virussen en chemische stoffen zo vroeg mogelijk in beeld te brengen, is in 2020 het Signaleringsoverleg Voedselveiligheid gestart. Dit overleg is opgezet om nieuwe risico’s voor de voedselveiligheid zo vroeg mogelijk in beeld te brengen. Met deze informatie kunnen sneller maatregelen worden genomen om de gezondheid van mensen te beschermen.Het Signaleringsoverleg heeft twee onderdelen: een overleg over microbiologische risico’s (het SO-VM) en een overleg over chemische risico’s (het SO-VC). In beide onderdelen zitten experts op het gebied van voedselveiligheid van verschillende instituten en het bedrijfsleven. Deze experts verzamelen signalen die zij met elkaar bespreken en betekenis geven. In 2021 zijn beide onderdelen elk vier keer bij elkaar gekomen. In totaal zijn 73 signalen ingebracht en uitgewerkt.Als er naar aanleiding van een signaal meer onderzoek of maatregelen nodig zijn, meldt het Signaleringsoverleg het signaal aan het Coördinerend Overleg. Hierin zijn de ministeries van Volksgezondheid,Welzijn en Sport (VWS) en Landbouw, Natuur en Voedselkwaliteit (LNV) en de Nederlandse Voedsel- en Warenautoriteit (NVWA)vertegenwoordigd. In 2021 heeft het SO-VM één signaal gemeld, en het SO-VC heeft 8 signalen gemeld aan het Coördinerend Overleg