Silver in the meat and organs of broiler chickens in case of using colloidal silver as an alternative to antibiotics

The search for new antibacterial products, the mechanisms of action of which differ from conventional antibiotics is a current a topical issue. The objective of our research is to identify the presence of silver in meat and organs of broiler chicks that had been given colloidal silver. The results show that the broiler chick meat contains silver in quantities safe for humans regardless of the use of colloidal silver. Comparison of meat analysis results in experimental and control groups indicate that the ratio of parameters distribution variance for all birds to the mean variance by group for each measured no statistical differences in the chemical composition of bird’s meat of experimental and control groups. The analysis also confirmed the existing difference in chemical composition of leg muscle meat and chest muscle meat (P?<?0.05), whereas leg muscle contains more fat (6.81% vs. 2.85%) and less protein (20.25% vs. 22.81%).     

Field testing of transgenic aspen from large greenhouse screening identifies unexpected winners

Trees constitute promising renewable feedstocks for biorefinery using biochemical conversion, but their recalcitrance restricts their attractiveness for the industry. To obtain trees with reduced recalcitrance, large-scale genetic engineering experiments were performed in hybrid aspen blindly targeting genes expressed during wood formation and 32 lines representing seven constructs were selected for characterization in the field. Here we report phenotypes of five-year old trees considering 49 traits related to growth and wood properties. The best performing construct considering growth and glucose yield in saccharification with acid pretreatment had suppressed expression of the gene encoding an uncharacterized 2-oxoglutarate-dependent dioxygenase (2OGD). It showed minor changes in wood chemistry but increased nanoporosity and glucose conversion. Suppressed levels of SUCROSE SYNTHASE, (SuSy), CINNAMATE 4-HYDROXYLASE (C4H) and increased levels of GTPase activating protein for ADP-ribosylation factor ZAC led to significant growth reductions and anatomical abnormalities. However, C4H and SuSy constructs greatly improved glucose yields in saccharification without and with pretreatment, respectively. Traits associated with high glucose yields were different for saccharification with and without pretreatment. While carbohydrates, phenolics and tension wood contents positively impacted the yields without pretreatment and growth, lignin content and S/G ratio were negative factors, the yields with pretreatment positively correlated with S lignin and negatively with carbohydrate contents. The genotypes with high glucose yields had increased nanoporosity and mGlcA/Xyl ratio, and some had shorter polymers extractable with subcritical water compared to wild-type. The pilot-scale industrial-like pretreatment of best-performing 2OGD construct confirmed its superior sugar yields, supporting our strategy.     

The effect of composition and ionic strength of external solution on the aspartate-ammonia lyase and fumarate hydratase activity in Escherichia coli cells

It was found that the nonspecific effect of ionic strength of the external solution on the enzymatic activity of E. coli cells consists in rapid changes in the permeability of cell membranes interacting with the substrate. This effect depends on the initial substrate concentration, i.e., ionic strength of the external solution, and is maintained for some time as the substrate concentration decreases. Chloramphenicol, a protein synthesis inhibitor, and sodium azide, a respiration inhibitor (300 micrograms/ml and 200 microM, respectively) do not change the enzymatic activity of E. coli cells during the synthesis of L-aspartic and L-malic acids from fumaric acid. The kinetic equations of L-aspartate and L-malate synthesis are described by equations of zero and intermediate (between zero and first) order, respectively.     

Probing the Huntingtin 1-17 Membrane Anchor on a Phospholipid Bilayer by Using All-Atom Simulations

Mislocalization and aggregation of the huntingtin protein are related to Huntington’s disease. Its first exon—more specifically the first 17 amino acids (Htt17)—is crucial for the physiological and pathological functions of huntingtin. It regulates huntingtin’s activity through posttranslational modifications and serves as an anchor to membrane-containing organelles of the cell. Recently, structure and orientation of the Htt17 membrane anchor were determined using a combined solution and solid-state NMR approach. This prompted us to refine this model by investigating the dynamics and thermodynamics of this membrane anchor on a POPC bilayer using all-atom, explicit solvent molecular dynamics and Hamiltonian replica exchange. Our simulations are combined with various experimental measurements to generate a high-resolution atomistic model for the huntingtin Htt17 membrane anchor on a POPC bilayer. More precisely, we observe that the single α-helix structure is more stable in the phospholipid membrane than the NMR model obtained in the presence of dodecylphosphocholine detergent micelles. The resulting Htt17 monomer has its hydrophobic plane oriented parallel to the bilayer surface. Our results further unveil the key residues interacting with the membrane in terms of hydrogen bonds, salt-bridges, and nonpolar contributions. We also observe that Htt17 equilibrates at a well-defined insertion depth and that it perturbs the physical properties—order parameter, thickness, and area per lipid—of the bilayer in a manner that could favor its dimerization. Overall, our observations reinforce and refine the NMR measurements on the Htt17 membrane anchor segment of huntingtin that is of fundamental importance to its biological functions.