THE ANIMAL PHOSPHOLIPIDS: THEIR STRUCTURE, METABOLISM and BIOLOGICAL SIGNIFICANCE

Internal extractive electrospray ionization mass spectrometry for investigating the phospholipid dysregulation induced by perfluorooctanoic acid in Nile tilapia

Direct profiling of endogenous biomolecules in tissue samples is considered to be a promising approach to investigate metabolic-related toxicity in organisms induced by emerging pollutants.

The methods of vibrational microspectroscopy reveals long-term biochemical anomalies within the region of mechanical injury within the rat brain

Traumatic brain injury (TBI), meaning functional or structural brain damage which appear as a result of the application of the external physical force, constitutes the main cause of death and disability of individuals and a great socioeconomic problem. To search for the new therapeutic strategies for TBI, better knowledge about posttraumatic pathological changes occurring in the brain is necessary. Therefore in the present paper the Fourier transform infrared microspectroscopy and Raman microscopy were used to examine local and remote biochemical changes occurring in the rat brain as a result of focal cortex injury. The site of the injury and the dorsal part of the hippocampal formation together with the above situated cortex and white matter were the subject of the study. The topographic and quantitative biochemical analysis followed with the statistical study using principal component analysis showed significant biomolecular anomalies within the lesion site but not in the area of the dorsal hippocampal formation and in the above situated white matter and cortex. The observed intralesional anomalies included significantly decreased accumulation of lipids and their structural changes within the place of injury. Also the levels of compounds containing phosphate and carbonyl groups were lower within the lesion site comparing to the surrounding cortex. The opposite relation was, in turn, found for the bands characteristic to proteins and cholesterol/cholesterol esters.

Dynamics of amphiphilic block copolymers in an aqueous solution: direct imaging of micelle formation and nanoparticle encapsulation

Micelles formed through the aggregation of amphiphilic block copolymers are ideal drug nanocarriers. Despite their importance in nanomedicine, the detailed mechanisms through which micelles form and copolymers encapsulate the target nanomaterials are unclear. Here, using in situ liquid cell transmission electron microscopy imaging, we capture both the dynamics of micelle formation and their encapsulation of gold nanoparticles (NPs) in an aqueous solution. Our observations reveal that the amphiphilic block copolymers aggregate and rearrange to form a micelle with a hydrophobic and rigid core, surrounded by a corona of hydrophilic blocks that extend into the solution. These micelles are stable against coalescence, and once mature, they do not merge. We also show that the encapsulation of hydrophobic NPs is a self-limiting process, which occurs through gradual adsorption of block copolymers; the growth of a polymeric shell around the NPs, shielding them from water, ceases when the NPs are fully covered by the adsorbed copolymers. The insights from these observations are of fundamental importance for the design of biocompatible soft materials.

Synthesis of Phosphatidylserine and Its Stereoisomers: Their Role in Activation of Blood Coagulation

Natural phosphatidylserine (PS), which contains two chiral centers, enhances blood coagulation. However, the process by which PS enhanced blood coagulation is not completely understood. An efficient and flexible synthetic route has been developed to synthesize all of the possible stereoisomers of PS. In this study, we examined the role of PS chiral centers in modulating the activity of the tissue factor (TF)-factor VIIa coagulation initiation complex. Full length TF was relipidated with phosphatidylcholine, and the synthesized PS isomers were individually used to estimate the procoagulant activity of the TF-FVIIa complex via a FXa generation assay. The results revealed that the initiation complex activity was stereoselective and had increased sensitivity to the configuration of the PS glycerol backbone due to optimal protein-lipid interactions.

Lipids in the skin of a cat-fish Heteropneustes fossilis (Bloch) (Heteropneustidae, Pisces). A histochemical investigation

Localization and characterization of different lipids in the cellular constituents of the skin of Heteropneustes fossilis has been made using several histochemical techniques. High contents of cholesterol, its esters and phospholipids have been correlated with the metabolically active state of the basal cells undergoing cell proliferation and differentiation. The polygonal cells in the outermost layer of the epidermis, though rich in phospholipid contain small amounts of cholesterol and its esters. This has been correlated with the metabolically less active state of theses cells. Neutral lipids and phospholipids in the polygonal cells of the outermost layer may contribute to the contents of surface slime and act as an efficient barrier for the penetration of water through the skin. The deposits of neutral lipids in the subcutis may provide energy during the period of fasting, act as a barrier for water diffusion through the skin and serve as shock absorbing pads protecting the fish from mechanical injury.