Decoding the drivers of deep-time wetland biodiversity: insights from an early Permian tropical lake ecosystem

Wetlands are important to continental evolution, providing both arenas and refugia for emerging and declining biotas. This significance and the high preservation potential make the resulting fossiliferous deposits essential for our understanding of past and future biodiversity. We reconstruct the trophic structure and age of the early Permian Manebach Lake ecosystem, Germany, a thriving wetland at a time when the tropical biosphere faced profound upheaval in the peaking Late Palaeozoic Icehouse. Nine excavations, high-resolution spatiotemporal documentation of fossils and strata, and U–Pb radioisotopic dating of tuffs allow us to distinguish autogenic and allogenic factors shaping the limnic biocoenosis. The Manebach Lake was an exorheic, oxygen-stratified, perennial water body on the 10¹–10² km² scale, integrated into the catchment draining much of the European Variscides. Lake formation paralleled an Asselian regional wet climatic interval and benefited from rising base level due to post-Variscan half-graben tectonics. Stromatolite-forming cyanobacteria, bivalves, several crustaceans, amblypterids and xenacanthid sharks formed a differentiated biocoenosis in the lake. Fossil stomach remains and teeth prove the rare presence of acanthodians, branchiosaurs and large amphibians. The results indicate woody-debris-bearing lake littorals devoid of semi-aquatic and aquatic plants as places suitable for stromatolites to grow, underpin the model of declining freshwater-shark diversity in most Permian Variscan basins, demonstrate fish/amphibian ratios in limnic assemblages to measure lake perenniality and reveal taphonomic biases in lake taphocoenoses. Our outcomes call for more knowledge about the diversity, ecology and fossilization pathways of past limnic biotas, particularly microorganisms and actinopterygian fishes, to reconstruct deep-time continental ecosystems.     

Characterization of soy protein hydrolysates and influence of its iron content on monoclonal antibody production by a murine hybridoma cell line

A challenging aspect with the use of protein hydrolysates in commercial manufacturing processes of recombinant therapeutic proteins is their impacts on the protein production due to a lack of understanding of batch-to-batch variability. Soy hydrolysates variability and its impact on fed-batch production of a recombinant monoclonal antibody (mAb) expressed in Sp2/0 cells were studied using 37 batches from the same vendor. The batch-to-batch variability of soy hydrolysates impacted cell growth, titer and product quality. Physicochemical characterization of batches confirmed that soy hydrolysates are mainly a source of amino acids and peptides containing lower amounts of other components such as carbohydrates and chemical elements in cell culture media. Soy hydrolysates composition of different batches was consistent except for trace elements. Statistical analyses identified iron as a potential marker of a poor process performance. To verify this correlation, two forms of iron, ferric ammonium citrate and ferrous sulfate, were added to a batch of soy hydrolysates associated to a low level of iron during cell culture. Both forms of iron reduced significantly cell growth, mAb titer and increased level of the acidic charge variants of the mAb. Consequently, trace element composition of soy hydrolysates or of all incoming raw materials might lead to significant impacts on process performance and product quality and therefore need to be tightly controlled.