RESUMO
Background: Chiari malformation type 1 (C1M) is a neurological disease characterized by herniation of the cerebellar tonsils below the foramen magnum. Cranial bone constriction is suspected to be its main cause. To date, genes related to bone development (e.g. DKK1 or COL1A2) have been associated with C1M, while some bone diseases (e.g. Paget) have been found to cosegregate with C1M. Nevertheless, the association between bone mineral density (BMD) and C1M has not been investigated, yet. Here, we systematically investigate the association between C1M and BMD, and between bone related genes and C1M. Methods: We have recruited a small cohort of C1M patients (12 unrelated patients) in whom we have performed targeted sequencing of an in-house bone-related gene panel and BMD determination through non-invasive DXA. Results: In the search for association between the bone related genes and C1M we have found variants in more than one C1M patient in WNT16, CRTAP, MYO7A and NOTCH2. These genes have been either associated with craniofacial development in different ways, or previously associated with C1M (MYO7A). Regarding the potential link between BMD and C1M, we have found three osteoporotic patients and one patient who had high BMD, very close to the HBM phenotype values, although most patients had normal BMD. Conclusions: Variants in bone related genes have been repeatedly found in some C1M cases. The relationship of bone genes with C1M deserves further study, to get a clearer estimate of their contribution to its etiology. No direct correlation between BMD and C1M was observed.
RESUMO
Fructooligosaccharides (FOS) are prebiotics commonly manufactured using fungal fructosyltransferases (FTases) or ß-fructofuranosidases. Several reports have attempted to optimize FOS production by changing operational conditions. Nevertheless, there is a lack of information related to the molecular enzyme-substrate interaction. In this study, we present an in silico evaluation of the interactions between substrates (i.e., glucose, sucrose, GF2, GF3, and GF4) and native FOS-synthesizing enzymes from fungi, with reported FOS production yield. In addition, a molecular dynamic simulation was conducted to assess the stability of these interactions. Six fungal enzymes with reported data of FOS production were selected: sucrose-sucrose 1-fructosyltransferase from A. foetidus (GenBank No. CAA04131); intracellular invertase from A. niger (GenBank No. ABB59679); extracellular invertase from A. niger (GenBank No. ABB59678); ß-fructofuranidase from A. japonicus ATCC 20611 (GenBank No. BAB67771); fructosyltransferase from A. oryzae N74 (GenBank No. ACZ48670); and fructosyltransferase from A. japonicus (PDB ID 3LF7). These enzymes shared an identity between 15 and 96 %, but have a highly conserved folding, and the characteristic FTases domains. Docking results showed that these enzymes also share a similar protein-ligand interaction profile. It was observed that the production yield of total FOS correlated with the sum of affinity energies for GF2, GF3, and GF4. Finally, we present the first molecular dynamic simulation for FOS and fungal FOS-synthesizing enzymes, showing that the protein-ligand interaction does not induce significant changes on the enzyme stability. Overall, these results represent valuable information to continue understanding the FOS synthesis process by fungal FOS-synthesizing enzymes, and they can have a significant impact toward the improvement in their catalytic properties and the synthesis of specific FOS.
