The relationship between structural lipids of sheep wool with its individual macrostructural components, chemical composition and physical indicators

The data on the peculiarities of the structural organization, chemical composition and physical parameters of sheep wool of different breeds depending on the type of their hair are presented. It has been found that the down fibers of ewes of the Ukrainian Carpathian Mountain breed possess the lowest content of β-keratosis (10.2%) and the highest content of α-keratosis (64.4%). In the fine wool of Ascanian ewes and Prekos ewes, the content of β-keratosis is 12.9 and 11.5%, respectively, and the highest content of it (15.1%) is contained in the guard fibers of the Carpathian Mountain ewes. However, in the down fibers of these ewes and the Prekos breed ewes, there is the highest content of γ-keratosis ― 28.4 and 28.7%, the total sulfur and cystine (2.9 and 2.9 and 11.2 and 11.5%), respectively. Besides that, the guard fibers contain the lowest content of both γ-keratosis (58.2%) and sulfur and cystine (2.7 and 9.0%), respectively. It has been established that different categories of fibers contain different amounts of total lipids. The smallest amounts of free lipids are found in the thin down of the Carpathian Mountain ewes (0.75%), the thin wool of the Prekos ewes (0.71%) and Ascanian ewes (0.83%), and the largest number of them is found in the semi-coarse guard fibers of the Carpathian Mountain sheep (1.39%). For bound lipids, a diametrically opposite difference was established: the largest amount of lipids was found in the thin down (1.85%), and the smallest amount — in the semi-coarse guard fibers (1.47%). In the guard fibers, the biggest amount of free lipids is accounted for the fraction of non-esterified cholesterol (64.9% versus 56.5% in the down, 57.7 in the wool of Ascanian ewes and 63.3% in the Prekos ewes), and the least of all they contain the fraction of non-esterified fatty acids (9.6%), and another sterol fraction (9.2%). The fibers of the Prekos breed sheep are noted with the lowest content of esterified cholesterol (8.9%) and the highest content of non-esterified fatty acids. But the fraction of polar lipids consists of almost 50% of ceramides and sulfolipids (more than 20%). At the same time, ceramides account for no more than 40% in the fraction of bound lipids. Physical indicators of wool to some extent reflect the peculiarities of its structure and chemical composition. Thus, the guard fibers have the highest strength (9.1 cN/tex) and fineness (48.8 μm), which is natural, because the guard has the highest content of β-keratose, i.e. cuticle, and the highest amount of lipids. Instead, the thinnest fibers are down fibers (16.9 μm) and they are the weakest (7.0 cN/tex) and these fibers contain the least β-keratose. Thus, there is a direct relationship between the content of the free lipid fraction and the fiber diameter (r = 0.996; 0.887; 0746 for down, fine and semi-coarse, respectively), and between the content of bound lipids — inverse (r = –0.993;–0.995; –0.694).

The role of alpha-helix on the structure-targeting drug design of amyloidogenic proteins

The most accredited hypothesis links the toxicity of amyloid proteins to their harmful effects on membrane integrity through the formation of prefibrillar-transient oligomers able to disrupt cell membranes. However, damage mechanisms necessarily assume a first step in which the amyloidogenic protein transfers from the aqueous phase to the membrane hydrophobic core. This determinant step is still poorly understood. However, according to our lipid-chaperon hypothesis, free lipids in solution play a crucial role in facilitating this footfall. Free phospholipid concentration in the aqueous phase acts as a switch between ion channel-like pore and fibril formation, so that high free lipid concentration in solution promotes pore and repress fibril formation. Conversely, low free lipids in the solution favor fibril and repress pore formation. This behavior is due to the formation of stable lipid-protein complexes. Here, we hypothesize that the helix propensity is a fundamental requirement to fulfill the lipid-chaperon model. The alpha-helix region seems to be responsible for the binding with amphiphilic molecules fostering the proposed mechanism. Indeed, our results show the dependency of protein-lipid binding from the helical structure presence. When the helix content is substantially lower than the wild type, the contact probability decreases. Instead, if the helix is broadening, the contact probability increases. Our findings open a new perspective for in silico screening of secondary structure-targeting drugs of amyloidogenic proteins.

Effect of use of extruded corn in broiler feed on yield and meat quality

The objective of these investigations was to examine the efficacy of the use of extruded feed in the diet of broiler chicks. The procedure of extruding corn causes significant physical-chemical changes in the kernel structure, which increases the nutritive value as the nutritive matter in the kernel becomes more readily available to the enzymes of the animal?s digestive tract. This procedure also increases hygiene safety as well as the sensory characteristics (taste) of the feed. Investigations were carried out on 3000 chicks of the Ross 308 hybrid, which were divided into an experimental and a control group. The fattening period lasted 49 days. The composition of the broiler mix was identical in both groups, with extruded corn being used in the mix for the control group (O). Broilers fed the mix with extruded corn (O) showed faster growth, lower mortality (20:96) and better feed conversion (2.04:2,13 kg/kg) in comparison with the control group (K). Broilers of the experimental group (O) also realized greater mass of the breast (696.6:657.6 g) and legs (569.2:528.2 g), as well as a greater meat percentage in the breast and legs. The diet with extruded corn also resulted in an improved nutritive quality of the broiler meat (higher protein content and lower content of free lipids in broiler meat). The meat of broilers fed the mix with extruded corn (O) was found to contain a higher protein content (23.35:22.58%) in the breast, and in the legs (18.26:17.67%), and a lower content of free lipids (1,.40:2.42%) in the breast, and in the legs (5.87:9.24%) in comparison with the meat of broilers of the control group (K).