CRYOPRESERVATION OF RAM SPERM FROM AUTOCHTHONOUS BREEDS DURING A NON-MATING SEASON

It is possible to collect and successfully cryopreserve ejaculates in a non-mating season from rams of the autochthonous breeds Karakachan, Cooper-red Shumen and Karnobat-local, raised in Bulgaria. Studies are in progress aiming the elaboration of optimal cryoprotective extenders and freezing technology

STIMULATION OF SEXUAL REFLEXES OF ABORIGINAL RAM BREEDS DURIN THE NON – MATING SEASON

The aim of the present study is to induce the sexual activity and to attain ejaculation during non-mating season in aboriginal ram breeds bred in Bulgaria. The possibility is discussed to use these rams with regard to the selection activity in effective sexual way

Development of 2D and 3D mucus models and their interactions with mucus-penetrating paclitaxel-loaded lipid nanocapsules.

International audiencePURPOSE: To study, diffusion through mucus (3D model) of different formulations of paclitaxel loaded lipid nanocapsules (Ptx-LNCs), to interpret the results in the light of LNC behavior at air-mucus interface (2D model).METHODS: LNC surface properties were modified with chitosan or poly(ethylene glycol) (PEG) coatings of different size (PEG 2,000 to 5,000 Da) and surface charges. LNC diffusion through 446 μm pig intestinal mucus layer was studied using Transwell(®). LNCs were spread at the air-water-mucus interface then interfacial pressure and area changes were monitored and the efficiency of triglyceride (TG) inclusion was determined.RESULTS: Ptx-LNCs of surface charges ranging from -35.7 to +25.3 mV were obtained with sizes between 56.2 and 75.1 nm. The diffusion of paclitaxel in mucus was improved after encapsulation in neutral or positively charged particles (p < 0.05 vs Taxol(®)). No significative difference was observed in the 2,000-5,000 PEG length for diffusion both on the 2D or 3D models. On 2D model positive or neutral LNCs interacted less with mucus. Highest efficiency of TG inclusion was observed for particles with smallest PEG length.CONCLUSIONS: The results obtained with 2D and 3D model allowed us to select the best candidates for in vivo studies (neutral or positive LNCs with smaller PEG length)

Phospholipase A₂‑Induced Remodeling Processes on Liquid-Ordered/Liquid-Disordered Membranes Containing Docosahexaenoic or Oleic Acid: A Comparison Study

Vesicle cycling, which is an important biological event, involves the interplay between membrane lipids and proteins, among which the enzyme phospholipase A₂ (PLA₂) plays a critical role. The capacity of PLA₂ to trigger the budding and fission of liquid-ordered (L_o) domains has been examined in palmitoyl-docosahexaenoylphosphatidylcholine (PDPC) and palmitoyl-oleoylphosphatidylcholine (POPC)/sphingomyelin/cholesterol membranes. They both exhibited a L_o/liquid-disordered (L_d) phase separation. We demonstrated that PLA₂ was able to trigger budding in PDPC-containing vesicles but not POPC ones. The enzymatic activity, line tension, and elasticity of the membrane surrounding the L_o domains are critical for budding. The higher line tension of L_o domains in PDPC mixtures was assigned to the greater difference in order parameters of the coexisting phases. The higher amount of lysophosphatidylcholine generated by PLA₂ in the PDPC-containing mixtures led to a less-rigid membrane, compared to POPC. The more elastic L_d membranes in PDPC mixtures exert a lower counteracting force against the L_o domain bending