Prediction of the three-dimensional structure of aflatoxin of Aspergillus flavus by homology modelling

Aflatoxins are polyketide-derived secondary metabolites produced by Aspergillus spp. The toxic effects of aflatoxins have adverse consequences for human health and agricultural economics. The aflR gene, a regulatory gene for aflatoxin biosynthesis, encodes a protein containing a zinc-finger DNA-binding motif. AFLR-Protein three-dimensional model was generated using Robetta server. The modeled AFLR-Protein was further optimization and validation using Rampage. In the simulations, we monitored the backbone atoms and the C-α-helix of the modeled protein. The low RMSD and the simulation time indicate that, as expected, the 3D structural model of AFLR-protein represents a stable folding conformation. This study paves the way for generating computer molecular models for proteins whose crystal structures are not available and which would aid in detailed molecular mechanism of inhibition of aflatoxin.     

The anti-infection resistance system and the pathogenesis of bacterial endocarditis in patients with congenital heart defects

The clinico-immuno-microbiological study of 24 patients with congenital heart diseases was made. Clinically, the patients were subdivided into two groups: 8 patients with diagnosed bacterial endocarditis (BE) prior to the operation and 16 patients without BE. The analysis of the results of investigation carried out prior to the operation showed that age, the form of the disease and its duration did not affect the level of anti-infectious resistance factors (AIRF): in both groups a decrease in the level of AIRF characteristics (cell-mediated and humoral) was noted and no characteristic differences were determined. The results of the study of microflora from the nasal and laryngeal mucosa showed no difference in both groups of the patients. At the same time the detailed analysis of the results made it possible to suggest that BE caused by Streptococcus epidermidis and Streptococcus aureus inhabiting the mucous membrane of the anterior sections of the nasal cavity, alpha-hemolytic streptococci and S. epidermidis inhibiting the laryngeal mucosa. The results of the analysis made 3-6 months after the operation were also indicative of the absence of essential differences between AIRF characteristics observed in patients with confirmed and clinically unconfirmed BE. The clinical manifestation of this fact was an increase in the percentage of diagnosed BE cases up to 70% as compared with that before the operation (33%). This clinico-immuno-microbiological study made it possible to come to the conclusion that any form of congenital heart disease develops in combination with BE and/or is its prodrome.     

Mapping the amino acid properties of constituent nucleoporins onto the yeast nuclear pore complex

Visualization of molecular structures aids in the understanding of structural and functional roles of biological macromolecules. Macromolecular transport between the cell nucleus and cytoplasm is facilitated by the nuclear pore complex (NPC). The ring structure of the NPC is large and contains several distinct proteins (nucleoporins) which function as a selective gate for the passage of certain molecules into and out of the nucleus. In this note we demonstrate the utility of a python code that allows direct mapping of the physiochemical properties of the constituent nucleoporins on the scaffold of the yeast NPC׳s cytoplasmic view. We expect this tool to be useful for researchers to visualize the NPC based on their physiochemical properties and how it alters when specific mutations are introduced in one or more of the nucleoporins. The code developed using Python is available freely from the authors.     

The treatment of isolated genera

Problems presented by genera, or small groups of genera, which have been given family rank are reviewed, and the genera are divided into a number of categories according to the closeness of their affinity to other genera or families. Satellite genera that stand in close relation to families should be united with them. Binary families, that have been divided into two (or more) related families, should be re–united. Families connected by linking genera, should, logically, be united but practical considerations usually prevent this. Clusters of diverse but more or less distantly related genera present unusual problems, being treated either as several, often monogeneric families or as a loosely structured family. Truly isolated genera must be given family and often ordinal rank.     

Changes in induction of slow fluorescence in leaves of maple located near urban highways

The slow fluorescence induction parameter FM/FT was measured for green leaves from maple trees grown in the park, depending on the distance (5-65 m) between the tree and the highway cross. We concluded that the decrease in the value of FM/FT for trees grown in the vicinity of the road cross was caused by exhaust gases.