Natural melanin features many interesting properties, including the ability to shield electromagnetic radiation, the ability to act as scavenger for radical and reactive oxygen species and the ...capacity to chelate different metal ions. For these reasons, melanin is becoming increasingly relevant for the development of functional materials with potential applications in cosmetics, drug delivery, and water purification. However, the extraction and purification of melanin from conventional sources (e.g., sepia ink, hair, and wool) is inefficient and not easily scalable, hence diverting its technological applications. Some fungal species, especially wood-decay basidiomycetes, can be regarded as promising sources of melanin. In the present study, we screened different fungi in regard to their melanin-biosynthesis abilities using l-tyrosine as a precursor, and we found that an Armillaria cepistipes strain (Empa 655) produced the highest yield of melanin (27.98 g L–1). Physicochemical characterization of the obtained fungal melanin revealed a typical eumelanin structure. The method for the biosynthesis of fungal melanin we propose is efficient, scalable, and sustainable and has the potential to provide support for further technological exploitation.
The Burgundy truffle (Tuber aestivum Vittad.), an ectomycorrhizal fungus living in association with host plants, is one of the most exclusive delicacies. The symbiosis with deciduous oak, beech, and ...hazel dominates our concept of truffle ecophysiology, whereas potential conifer hosts have rarely been reported. Here, we present morphological and molecular evidence of a wildlife T. aestivum symbiosis with Norway spruce (Picea abies Karst.) and an independent greenhouse inoculation experiment, to confirm our field observation in southwest Germany. A total of 27 out of 50 P. abies seedlings developed T. aestivum ectomycorrhizae with a mean mycorrhization rate of 19.6 %. These findings not only suggest P. abies to be a productive host species under suitable biogeographic conditions but also emphasize the broad ecological amplitude and great symbiotic range of T. aestivum. While challenging common knowledge, this study demonstrates a significant expansion of the species' cultivation potential to the central European regions, where P. abies forests occur on calcareous soils.
The paper analyzes social interactions among crowdworkers on Discord. The explored crowdtesting platform uses this social media platform to offer their crowdworkers various opportunities for ...work-related and private communication and to host events that encourage learning practices. The paper investigates to what extent the interactions on Discord can be analyzed as social learning practices and can be understood as a specific form of solidarity among crowdworkers. In an explorative online ethnographic study, two learning related channels of the platform company’s Discord server were observed: the question channel in which testers can ask for help, and the quiz channel in which a testing related quiz event takes place. Additionally, interviews with moderators and crowdtesters were conducted. The observation of learning practices on Discord makes clear that the social media tool is mostly used by testers for situational and functional information exchange like helping each other with bug classifications or solving technical problems. Testers mostly provide each other with brief information that can directly be applied in the work context. Further information are mainly shared by moderators that offer supplementary explanations as a possibility to self-help. The study highlights that a form of weak cooperative solidarity emerges among testers as they support each other via Discord to fulfill individual work tasks. This differs from resistant solidarity in other contexts of platform work, because in the observed case, platform workers’ solidarity is not directed against the platform company.
