Lipoprotein lipase: A bioinformatics criterion for assessment of mutations as a risk factor for cardiovascular disease

Lipoprotein lipase (LPL) is a key enzyme in lipid metabolism. Decrease of the LPL enzymatic activity leads to elevated triglycerides (TG) and reduced high-density lipoprotein (HDL-C levels), both risk factors for cardiovascular disease (CVD). Therefore, mutations, which decrease the LPL activity, may confer susceptibility to CVD. Here, the informational spectrum method (ISM), a virtual spectroscopy method for structure/function analysis of nucleotide and protein sequences, is applied for identification of evolutionary highly conserved information encoded by the primary structure of LPL. It was demonstrated that mutations, which alter the LPL enzymatic activity also alter this information. On the basis of this finding, an efficient and simple bioinformatics criterion for assessment of the pathogenic effect of LPL nonsynonymous single nucleotide substitution as a risk factor of CVD has been proposed.     

EMILINs interact with anthrax protective antigen and inhibit toxin action in vitro.

The informational spectrum method (ISM) is a virtual spectroscopy method for the fast analysis of potential protein-protein relationships. By applying the ISM approach to the GeneBank protein database the vascular proteins EMILIN1 (Elastin Microfibril Interface Located ProteIN), EMILIN2, MMN1, and MMN2 were identified as additional anthrax PA antigen interacting molecules. This virtual molecular interaction was formally proven by solid phase assays using recombinant proteins. The interaction is independent of the presence of divalent cations and does not involve PA aspartic residue at 683, a critical residue in receptor binding. In fact, the D683A point mutation fully prevented the cell intoxication ability of PA in the presence of Lethal Factor, but it was fully ineffective on the binding of mutated PA to EMILIN1 and EMILIN2. The ISM approach also led to the identification of the potential interaction sites between PA and EMILINs. A PA mutant with a deletion at residue D425 and solid phase protein-protein interaction studies as well as deletion mutant of EMILIN2 confirmed the hypothesized interaction site. Our findings imply that the PA-cell surface receptor interaction is not likely to provide the full explanation for the vascular lesions and prominent hemorrhages that follow Bacillus anthracis infection and spreading and call into play vascular associated proteins such as EMILINs as potential inhibitory proteins.     

New host plants of Erwinia amylovora in Bulgaria

Nine strains of Erwinia amylovora were isolated from new host plants in Bulgaria--chokeberry and strawberry. The strains were characterized morphologically and biochemically using the API 20E and BIOLOG system. It was established that they showed three different API 20E metabolic profiles, not found by previous studies of E. amylovora. All strains were identified as E. amylovora due to their metabolic fingerprint patterns obtained by the BIOLOG system. The identification was confirmed by PCR amplification of a specific region of plasmid pEA29 and genome ams-region. This study is the first characterization and identification of E. amylovora strains isolated from chokeberry and strawberry by the API 20E and BIOLOG system and by polymerase chain reaction.     

Evaluation of agronomic traits in tissue culture – derived progeny of bird's-foot trefoil

Two newly selected Lotus corniculatus cultivars (Bokor and Zora), introduced recently as pasture legumes, were studied with respect to their in vitro regeneration capacity and field performance of R₁ regenerates. Multiple buds were induced in callus tissues derived from apical buds, petioles, leaf and cotyledon explants. The rooted regenerates, acclimated in a greenhouse, were fertile. Seeds from the R₁ generation were sown in the field and the plants found to be superior to controls in stem height and green mass production.     

Conservation of Ephestia kuehniella eggs as hosts for Trichogramma ostriniae

Mass rearing of numerous biological control agents depends on large amounts of factitious hosts like Ephestia kuehniella eggs. Moreover, production of some parasitoids, such as Trichogramma, requires hosts of high quality. The objective of this study was to determine the optimal conservation method that allows E. kuehniella eggs to remain suitable for parasitism and development of Trichogramma ostriniae for the longest period of time. Fifteen sterilization–conservation treatments were compared: nine consisting of submersion of the eggs in liquid nitrogen as a conservation mode, two consisting of sterilization of the eggs with UV and four consisting of sterilization with freezing at ?15°C. Liquid nitrogen submersion of E. kuehniella eggs did not allow the production of T. ostriniae. The sterilization by exposition to UV light followed by conservation using vacuum packing and refrigeration at 4°C provided the longest conservation of E. kuehniella eggs for T. ostriniae rearing. It was the only treatment (75.4 ± 4.62%) for which the parasitism rate remained over 70% after 2 weeks.     

Kinetic Origin of Substrate Specificity in Post-Transfer Editing by Leucyl-tRNA Synthetase

The intrinsic editing capacities of aminoacyl-tRNA synthetases ensure a high-fidelity translation of the amino acids that possess effective non-cognate aminoacylation surrogates. The dominant error-correction pathway comprises deacylation of misaminoacylated tRNA within the aminoacyl-tRNA synthetase editing site. To assess the origin of specificity of Escherichia coli leucyl-tRNA synthetase (LeuRS) against the cognate aminoacylation product in editing, we followed binding and catalysis independently using cognate leucyl- and non-cognate norvalyl-tRNA^Leu and their non-hydrolyzable analogues. We found that the amino acid part (leucine versus norvaline) of (mis)aminoacyl-tRNAs can contribute approximately 10-fold to ground-state discrimination at the editing site. In sharp contrast, the rate of deacylation of leucyl- and norvalyl-tRNA^Leu differed by about 10⁴-fold. We further established the critical role for the A76 3′-OH group of the tRNA^Leu in post-transfer editing, which supports the substrate-assisted deacylation mechanism. Interestingly, the abrogation of the LeuRS specificity determinant threonine 252 did not improve the affinity of the editing site for the cognate leucine as expected, but instead substantially enhanced the rate of leucyl-tRNA^Leu hydrolysis. In line with that, molecular dynamics simulations revealed that the wild-type enzyme, but not the T252A mutant, enforced leucine to adopt the side-chain conformation that promotes the steric exclusion of a putative catalytic water. Our data demonstrated that the LeuRS editing site exhibits amino acid specificity of kinetic origin, arguing against the anticipated prominent role of steric exclusion in the rejection of leucine. This feature distinguishes editing from the synthetic site, which relies on ground-state discrimination in amino acid selection.     

Cardioprotective effects of high-intensity interval training are mediated through microRNA regulation of mitochondrial and oxidative stress pathways

Human studies have shown high-intensity interval training (HIIT) has beneficial cardiovascular effects and is typically more time-efficient compared with traditional endurance exercise. The main goal of this study is to show the potential molecular and functional cardiovascular benefits of HIIT compared with endurance training (ET). Three groups of mice were used including sedentary-control, ET mice, and HIIT mice groups. Results indicated ejection fraction was increased in HIIT compared with ET while fractional shortening was increased in the HIIT group compared with both groups. Blood flow of the abdominal aorta was increased in both exercise groups compared with control. Increases in cross-sectional area and mitochondrial and antioxidative markers in HIIT compared with control were observed, along with several microRNAs. These findings indicate HIIT has specific cardiac-protective effects and may be a viable alternative to traditional ET as a cardiovascular preventative medicine intervention.     

Orally bioavailable,liver-selective stearoyl-CoA desaturase (SCD) inhibitors

We discovered a structurally novel SCD (Δ9 desaturase) inhibitor 4a (CVT-11,563) that has 119 nM potency in a human cell-based (HEPG2) SCD assay and selectivity against Δ5 and Δ6 desaturases. This compound has 90% oral bioavailability (rat) and excellent plasma exposure (dAUC 935 ng h/mL). Additionally, 4a shows moderately selective liver distribution (three times vs plasma and adipose tissue) and relatively low brain penetration. In a five-day study (high sucrose diet, rat) compound 4a significantly reduced SCD activity as determined by GC analysis of fatty acid composition in plasma and liver. We describe the discovery of 4a from HTS hit 1 followed by scaffold replacement and SAR studies focused on DMPK properties.