Ortega-Hernández, J., Lerosey-Aubril, R., Pates, S., 2019. Proclivity of nervous system preservation in Cambrian Burgess Shale-type deposits. Proceedings of the Royal Society B: Biological Sciences 286, 20192370.

https://royalsocietypublishing.org/doi/abs/10.1098/rspb.2019.2370 Recent investigations on neurological tissues preserved in Cambrian fossils have clarified the phylogenetic affinities and head segmentation in pivotal members of stem-group Euarthropoda. However, palaeoneuroanatomical features are often incomplete or described from single exceptional specimens, raising concerns about the morphological interpretation of fossilized neurological structures and their significance for early euarthropod evolution. Here, we describe the central nervous system (CNS) of the short great-appendage Alalcomenaeus euarthropod based on material from two Cambrian Burgess Shale-type deposits of the American Great Basin, the Pioche Formation (Stage 4) and the Marjum Formation (Drumian). The specimens reveal complementary ventral and lateral views of the CNS, preserved as a dark carbonaceous compression throughout the body. The head features a dorsal brain connected to four stalked ventral eyes, and four pairs of segmental nerves. The first to seventh trunk tergites overlie a ventral nerve cord with seven ganglia, each associated with paired sets of segmental nerve bundles. Posteriorly, the nerve cord features elongate thread-like connectives. The Great Basin fossils strengthen the original description - and broader evolutionary implications - of the Alalcomenaeus CNS in from the early Cambrian (Stage 3) Chengjiang deposit of South China. The spatio- temporal recurrence of fossilized neural tissues in Cambrian Konservat-Lagerstätten across North America (Pioche, Burgess Shale, Marjum) and South China (Chengjiang, Xiaoshiba) indicates that their preservation is consistent with the mechanism of Burgess Shale-type fossilization, without the need to invoke alternative taphonomic pathways or the presence of microbial biofilms.

Oshlag, J.Z., Ma, Y., Morse, K., Burger, B.T., Lemke, R.A., Karlen, S.D., Myers, K.S., Donohue, T.J., Noguera, Rhodopseudomonas palustris D.R., 2020. Anaerobic degradation of syringic acid by an adapted strain of . Applied and Environmental Microbiology 86, e01888-19.

http://aem.asm.org/content/86/3/e01888-19.abstract Abstract: While lignin represents a major fraction of the carbon in plant biomass, biological strategies to convert the components of this heterogeneous polymer into products of industrial and biotechnological value are lacking. Syringic acid (3,5-dimethoxy-4-hydroxybenzoic acid) is a by-product of lignin degradation, appearing in lignocellulosic hydrolysates, deconstructed lignin streams, and other agricultural products. Rhodopseudomonas palustris CGA009 is a known degrader of phenolic compounds under photoheterotrophic conditions via the benzoyl coenzyme A (CoA) degradation (BAD) pathway. However, R. palustris CGA009 is meta reported to be unable to metabolize -methoxylated phenolics, such as syringic acid. We isolated a strain of R. palustris (strain SA008.1.07), adapted from CGA009, which can grow on syringic acid under photoheterotrophic conditions, utilizing it as a sole source of organic carbon and reducing power. An SA008.1.07 mutant with an inactive benzoyl-CoA reductase structural gene was able to grow on syringic acid, demonstrating that the metabolism of this aromatic compound is not through the BAD pathway. Comparative vanARB gene expression analyses of SA008.1.07 implicated the involvement of products of the operon rpa3619 rpa3620 rpa3621 ( , , ), which has been described as catalyzing aerobic aromatic ring demethylation in vanARB other bacteria, in anaerobic syringic acid degradation. In addition, experiments with a deletion mutant vanARB demonstrated the involvement of the operon in anaerobic syringic acid degradation. These observations meta provide new insights into the anaerobic degradation of -methoxylated and other aromatics by R. palustris. Importance: Lignin is the most abundant aromatic polymer on Earth and a resource that could eventually substitute for fossil fuels as a source of aromatic compounds for industrial and biotechnological applications. Engineering microorganisms for the production of aromatic-based biochemicals requires detailed knowledge of the metabolic pathways for the degradation of aromatics that are present in lignin. Our isolation and analysis of a Rhodopseudomonas palustris strain capable of syringic acid degradation reveal a previously unknown metabolic route for aromatic degradation in R. palustris. This study highlights several key features of this pathway and sets the stage for a more complete understanding of the microbial metabolic repertoire required to metabolize aromatic compounds from lignin and other renewable sources.