Deletion of flbA results in increased secretome complexity and reduced secretion heterogeneity in colonies of Aspergillus niger.

Aspergillus niger is a cell factory for the production of enzymes. This fungus secretes proteins in the central part and at the periphery of the colony. The sporulating zone of the colony overlapped with the nonsecreting subperipheral zone, indicating that sporulation inhibits protein secretion. Indeed, strain ΔflbA that is affected early in the sporulation program secreted proteins throughout the colony. In contrast, the ΔbrlA strain that initiates but not completes sporulation did not show altered spatial secretion. The secretome of 5 concentric zones of xylose-grown ΔflbA colonies was assessed by quantitative proteomics. In total 138 proteins with a signal sequence for secretion were identified in the medium of ΔflbA colonies. Of these, 18 proteins had never been reported to be part of the secretome of A. niger, while 101 proteins had previously not been identified in the culture medium of xylose-grown wild type colonies. Taken together, inactivation of flbA results in spatial changes in secretion and in a more complex secretome. The latter may be explained by the fact that strain ΔflbA has a thinner cell wall compared to the wild type, enabling efficient release of proteins. These results are of interest to improve A. niger as a cell factory.

Prospective Real-World Gynaecological Cancer Clinical Registry with Associated Biospecimens: A Collaborative Model to Promote Translational Research between GEICO and the Spanish Biobank Network.

Patient registries linked to biorepositories constitute a valuable asset for clinical and translational research in oncology. The Spanish Group of Ovarian Cancer Research (GEICO), in collaboration with the Spanish Biobank Network (RNBB), has developed a multicentre, multistakeholder, prospective virtual clinical registry (VCR) associated with biobanks for the collection of real-world data and biological samples of gynaecological cancer patients. This collaborative project aims to promote research by providing broad access to high-quality clinical data and biospecimens for future research according to the needs of investigators and to increase diagnostic and therapeutic opportunities for gynaecological cancer patients in Spain. The VCR will include the participation of more than 60 Spanish hospitals entering relevant clinical information in harmonised electronic case report forms (eCRFs) in four different cohorts: ovarian, endometrial, cervical, and rare gynaecological cancers (gestational trophoblastic disease). Initial data for the cases included till December 2021 are presented. The model described herein establishes a real-world win-win collaboration between multicentre structures, promoted and supported by GEICO, that will contribute to the success of translational research in gynaecological cancer.

Spatial differentiation in the vegetative mycelium of Aspergillus niger.

Fungal mycelia are exposed to heterogenic substrates. The substrate in the central part of the colony has been (partly) degraded, whereas it is still unexplored at the periphery of the mycelium. We here assessed whether substrate heterogeneity is a main determinant of spatial gene expression in colonies of Aspergillus niger. This question was addressed by analyzing whole-genome gene expression in five concentric zones of 7-day-old maltose- and xylose-grown colonies. Expression profiles at the periphery and the center were clearly different. More than 25% of the active genes showed twofold differences in expression between the inner and outermost zones of the colony. Moreover, 9% of the genes were expressed in only one of the five concentric zones, showing that a considerable part of the genome is active in a restricted part of the colony only. Statistical analysis of expression profiles of colonies that had either been or not been transferred to fresh xylose-containing medium showed that differential expression in a colony is due to the heterogeneity of the medium (e.g., genes involved in secretion, genes encoding proteases, and genes involved in xylose metabolism) as well as to medium-independent mechanisms (e.g., genes involved in nitrate metabolism and genes involved in cell wall synthesis and modification). Thus, we conclude that the mycelia of 7-day-old colonies of A. niger are highly differentiated. This conclusion is also indicated by the fact that distinct zones of the colony grow and secrete proteins, even after transfer to fresh medium.

Localization of protein secretion in fungal colonies using a novel culturing technique; the ring-plate system.

A novel culturing technique, called the ring-plate system, is described. Fungal colonies are grown on a polycarbonate membrane placed on a plate with 6 ring-shaped wells that are filled with liquid medium. This culturing technique enables simultaneous monitoring of environmental conditions and secretion in different parts of the fungal colony.