NMR spectrum of lindgomycin from a Marine Fungus of the Lindgomycetaceae

An unusual polyketide with a new carbon skeleton, lindgomycin (1), and the recently described ascosetin (2) were extracted from mycelia and culture broth of different Lindgomycetaceae strains, which were isolated from a sponge of the Kiel Fjord in the Baltic Sea (Germany) and from the Antarctic. Their structures were established by spectroscopic means. In the new polyketide, two distinct domains, a bicyclic hydrocarbon and a tetramic acid, are connected by a bridging carbonyl. The tetramic acid substructure of compound 1 was proved to possess a unique 5-benzylpyrrolidine-2,4-dione unit. The combination of 5-benzylpyrrolidine-2,4-dione of compound 1 in its tetramic acid half and 3-methylbut-3-enoic acid pendant in its decalin half allow the assignment of a new carbon skeleton. The new compound 1 and ascosetin showed antibiotic activities with IC50 value of 5.1 (±0.2) µM and 3.2 (±0.4) µM, respectively, against methicillin-resistant Staphylococcus aureus.

Experiment on marine fungus Microascus brevicaulis strain

The marine fungus Microascus brevicaulis strain LF580 is a non-model secondary metabolite producer with high yields of the two secondary metabolites scopularide A and B, which exhibit distinct activities against tumour cell lines. A mutant strain was obtained using UV mutagenesis, showing besides higher production levels faster growth and differences in pellet formation. Comparative proteomics were applied to gain deeper understanding of the regulation of production and of the physiology of this fungus and its mutant. For this purpose, an optimised protein extraction protocol was established. Here, we show the first proteome study of a marine fungus. In total, 4759 proteins were identified. The central metabolic pathway of LF580 could be mapped by using KEGG pathway analysis and GO annotation. Using iTRAQ labelling, 318 proteins were shown to be significantly regulated in the mutant strain: 189 were down- and 129 upregulated. Proteomics are a powerful tool for the understanding of regulatory aspects: The differences on proteome level could be attributed to a limited nutrient availability in wild type strain due to a strong pellet formation. This information can be applied to optimisation on strain and process level. The linkage between nutrient limitation and pellet formation in the non-model fungus M. brevicaulis is in consensus with the knowledge on model organisms like Aspergillus niger and Penicillium chrysogenum.

Superoxide decay rates during METEOR cruise M83/1

Superoxide is an important transient reactive oxygen species (ROS) in the ocean formed as an intermediate in the redox transformation of oxygen (O2) into hydrogen peroxide (H2O2) and vice versa. This highly reactive and very short-lived radical anion can be produced both via photochemical and biological processes in the ocean. In this paper we examine the decomposition rate of O2- throughout the water column, using new data collected in the Eastern Tropical North Atlantic (ETNA) Ocean. For this approach we applied a semi factorial experimental design, to identify and quantify the pathways of the major identified sinks in the ocean. In this work we occupied 6 stations, 2 on the West African continental shelf and 4 open ocean stations, including the CVOO time series site adjacent to Cape Verde. Our results indicate that in the surface ocean, impacted by Saharan aerosols and sediment resuspension, the main decay pathways for superoxide is via reactions with Mn(||) and organic matter.

Viral decay and production in sediments of the Mediterranean Sea

Here, for the first time, we have carried out synoptic measurements of viral production and decay rates in continental-shelf and deep-sea sediments of the Mediterranean Sea to explore the viral balance. The net viral production and decay rates were significantly correlated, and were also related to prokaryotic heterotrophic production. The addition of enzymes increased the decay rates in the surface sediments, but not in the subsurface sediments. Both the viral production and the decay rates decreased significantly in the deeper sediment layers, while the virus-to-prokaryote abundance ratio increased, suggesting a high preservation of viruses in the subsurface sediments. Viral decay did not balance viral production at any of the sites investigated, accounting on average for c. 32% of the gross viral production in the marine sediments. We estimate that the carbon (C) released by viral decay contributed 6-23% to the total C released by the viral shunt. Because only ca. 2% of the viruses produced can infect other prokaryotes, the majority is not subjected to direct lysis and potentially remains as a food source for benthic consumers. The results reported here suggest that viral decay can play an important role in biogeochemical cycles and benthic trophodynamics.

Economic contribution of Chinese caterpillar fungus to the livelihoods of mountain communities in Nepal

Harvesting of Chinese caterpillar fungus, one of the most expensive biological commodities in the world, has become an important livelihood strategy for mountain communities of Nepal. However, very little is known about the role of Chinese caterpillar fungus in household economy. We estimated the economic contribution of Chinese caterpillar fungus to the household income, quantified the extent of "Chinese caterpillar fungus dependence" among households with different economic and social characteristics, and assessed the role of cash income from the Chinese caterpillar fungus harvest in meeting various household needs including education, debt payments, and food security. Results show that Chinese caterpillar fungus income is the second largest contributor to the total household income after farm income with 21.1% contribution to the total household income and 53.3% to the total cash income. The contribution of Chinese caterpillar fungus income to total household income decreases as the household income increases making its contribution highest for the poorest households. There is significant correlation between Chinese caterpillar fungus dependency and percentage of family members involved in harvesting, number of food-sufficient months, and total income without Chinese caterpillar fungus income. Income from Chinese caterpillar fungus is helping the poorest to educate children, purchase food, and pay debts. However, reported decline of Chinese caterpillar fungus from its natural habitat might threaten local livelihoods that depend on the Chinese caterpillar fungus in future. Therefore, sustainable management of Chinese caterpillar fungus through partnership among local institutions and the state is critical in conserving the species and the sustained flow of benefits to local communities.