Using multivariate statistics to link major ion chemistry changes at karst springs to agriculture.

Agricultural contamination is a pervasive problem in karst landscapes that negatively impacts groundwater quality, and subsequently harms hydraulically connected springs and associated ecosystems. While most research on agricultural contamination in karst aquifers has focused on nitrate, agricultural operations also alter major ion chemistry in groundwater, which can have significant implications on water rock interactions, geochemical interpretability, and enrichment of harmful contamination. Additionally, recent evidence has questioned the singular role of nutrient enrichment on aquatic ecosystem degradation, thus prompting further investigation into the broader extent of agricultural contamination for improved water quality restoration.

Mechanism of chorismate dehydratase MqnA, the first enzyme of the futalosine pathway, proceeds via substrate-assisted catalysis.

MqnA, the only chorismate dehydratase known so far, catalyzes the initial step in the biosynthesis of menaquinone via the futalosine pathway. Details of the MqnA reaction mechanism remain unclear. Here, we present crystal structures of Streptomyces coelicolor MqnA and its active site mutants in complex with chorismate and the product 3-enolpyruvyl-benzoate, produced during heterologous expression in Escherichia coli.

Pathogenicity of human antibodies against myelin oligodendrocyte glycoprotein.

Objective: Autoantibodies against myelin oligodendrocyte glycoprotein (MOG) occur in a proportion of patients with inflammatory demyelinating diseases of the central nervous system (CNS). We analyzed their pathogenic activity by affinity-purifying these antibodies (Abs) from patients and transferring them to experimental animals.

Methods: Patients with Abs to MOG were identified by cell-based assay.

Histopathology and clinical course of MOG-antibody-associated encephalomyelitis.

We present histological, MRI, and clinical features of an adult patient with relapsing encephalomyelitis and antibodies against myelin oligodendrocyte glycoprotein (MOG). Furthermore, we report molecular details of the recognized epitope that is specific for human MOG. A brain biopsy revealed multiple sclerosis (MS)-type II pathology.

Structure of the Toll-Spatzle complex, a molecular hub in Drosophila development and innate immunity.

Drosophila Toll receptors are involved in embryonic development and the immune response of adult flies. In both processes, the only known Toll receptor ligand is the human nerve growth factor-like cystine knot protein Spätzle. Here we present the crystal structure of a 1:1 (nonsignaling) complex of the full-length Toll receptor ectodomain (ECD) with the Spätzle cystine knot domain dimer.