Assessing the effects of PMM2 variants on protein stability

Phosphomannomutase 2 deficiency, PMM2-CDG, is the most frequent disorder of protein N-glycosylation. It is an autosomal recessive disease with a broad clinical and biochemical phenotype. Trying to predict the impact of novel variants is often a challenge due to the high number of variants and the difficulty to establish solid genotype-phenotype correlations. A potential useful strategy is to use computational chemistry calculations as a tool from which relevant information on the structural impact of novel variants may be deduced. Here we present our analyses based on four well-known PMM2 deleterious variants (p.(Leu32Arg), p.(Asp65Tyr), p.(Phe119Leu), p.(Arg141His)) and the polymorphic p.(Glu197Ala) for which we have predicted the effect on protein stability. Our work predicts the effect of different amino acid residues on the conformation and stability of PMM2. These computational simulations are, therefore, an extremely useful methodology which, in combination with routinely used in silico methods of pathogenicity prediction, may help to reveal the structural impact of novel variants at the protein level, potentially leading to a better understanding of target biological molecules.

Identification of SNPs in growth-related genes in Colombian creole cattle

Colombian creole cattle have important adaptation traits related to heat tolerance and reproductive and productive efficiency. Romosinuano (ROMO) and Blanco Orejinegro (BON) are the most common breeds used by Colombian cattle breeders. Growth traits are of prime importance in these animals, which are mainly raised for beef production. Genes encoding growth hormone, growth hormone receptor, homeobox protein, insulin growth factor binding protein 3, leptin, and myostatin have been associated with physiological growth pathways in cattle and other species. We therefore aimed to identify single nucleotide polymorphisms (SNPs) within these genes in ROMO, BON, and Zebu cattle. DNA regions of these genes were sequenced in 386 animals; 47 new SNPs were found, of which 14 were located in the exonic regions, thereby changing the protein sequence. An association of SNPs with weaning weight (WW), daily weight gain at weaning (DWG), and weight at 16 months (W16M) traits was deduced. The genetic analysis revealed several SNPs related to these traits. The SNP GhRE06.2 had a significant association with WW and the SNP Lep03.4 was highly associated with DWG and W16M. Other polymorphisms were significantly associated with WW and DWG, although they did not surpass the Bonferroni significance threshold. The new mutations identified may indicate important points of genetic control in the DNA that could be responsible for changes in the expression of the analyzed traits. These SNPs might be used in future breeding programs to improve the productive performance of cattle in beef farms.

Androecia in two Clusia species: development, structure and resin secretion

Clusia fluminensis and C. lanceolata are dioecious shrubs having resiniferous flowers with strongly distinct androecia. The aim of this study was to investigate the development and anatomy of their androecia and the ultrastructure, histochemistry and secretory process of their androecium resin glands, examining whether the cellular aspects of resin secretion differed between these two morphologically distinct androecia. Stamens differ, being free in C. fluminensis and clustered in a synandrium in C. lanceolata. Staminode sterility is due to the undifferentiated nature of the anthers in C. lanceolata and degeneration of meiocytes and anther indehiscence in C. fluminensis. Resin is produced in subepidermal cavities and canals with wide lumens. In the secretory stage, epithelial cells present sinuous walls, voluminous nuclei, polymorphic plastids associated with periplastidial reticulum, mitochondria, oil bodies, multivesicular bodies, endoplasmic reticulum and dictyosomes. The resin is released through rupture points on the distal surface of stamens and staminodes, associated with disrupted cavities and canals. Our results show morphological diversity associated with functional similarity. Also, a secretion pattern shared by the two species includes initiation of the secretory process in young floral buds, compartmentalisation of the secretion in pre-anthesis buds and release of secretions at anthesis. Cellular aspects of resin secretion in these species are quite similar, as are the chemical identities of the main components of the floral resins of the genus.

Simultaneous supratentorial and brainstem abscesses due to Listeria monocytogenes

Multiple supratentorial abscesses caused by Listeria monocytogenes are rare. We report the simultaneous occurrence of multiple supratentorial and brainstem abscesses due to Listeria, in a patient under corticotherapy for an exacerbation of ulcerative colitis. MR imaging features before and after successful conservative treatments are depicted. In immunocompromised patients with supratentorial listerial abscesses, the coexistence of brainstem abscedation is exceptional. Despite high mortality associated with listerial abscesses, this case illustrates the possibility of a good clinical outcome, if the appropriate antibiotic regimen is instituted and the immunosuppressant agent is discontinued.