STUDIES OF SOLVENT EXTRACTION AND SUPPORTED LIQUID MEMBRANE WITH REACTIVE DYES FROM AQUEOUS SOLUTIONS USING ALIQUOT 336 AS CARRIER

The liquid-liquid extraction (LLE) and supported liquid membrane (SLM) studies of reactive dyes namely Gold Yellow (GYHE-R) and Reactive Green HE 4BD (RGHE-4BD) from aqueous solution using Aliquot 336 as the carrier has been investigated. Polytetrafluoroethylene (PTFE) membrane with 0.5 μm pore size has been used after impregnated with Aliquot 336 in dichloromethane. In liquid liquid extraction the following parameters had been optimized; pH of feed, diluent, carrier , strip and dye concentration and the same parameters have been applied to supported liquid membrane (SLM) study to transport dye from aqueous solution.The main advantages SLM study is; the extraction and stripping as single stage process and low consumption of carrier in the membrane phase compared to the solvent extraction process. The other parameters such as transport time, stirring speed and mechanism of dye transport has also studied by SLM. The percentage of transport of dye and flux rate increases with increasing time. The stability of membrane is satisfactory over 5 days.

Studies on rhodamine B dye transport through a supported liquid membrane from basic aqueous solutions using phenol as a membrane phase

The aim of this work is to investigate the transport of rhodamine B across a supported liquid membrane under various experimental conditions.

Endothelin axis induces metalloproteinase activation and invasiveness in human lymphatic endothelial cellsThis article is one of a selection of papers published in the two-part special issue entitled 20 Years of Endothelin Research.

The molecular mechanisms involved in lymphangiogenesis were unknown until recently. We previously demonstrated that the endothelin-1 (ET-1) axis stimulates lymphatic endothelial cells (LEC) and lymphatic vessels to grow and invade. Here we further investigated the effect of ET-1 on lymphatic vessels and evaluated whether ET-1 actions result in the functional activation of lymphangiogenesis. Using highly purified human LEC, characterized for the expression of ET-1 axis members by quantitative real-time PCR, we found that the endothelin B receptor (ETB), upon activation by ET-1, induced matrix-metalloproteinase activation, demonstrating that ET-1 influenced the activity of the proteolytic enzymes required for LEC invasion. Functional assays performed by using intradermal lymphangiography demonstrated that ET-1 promoted the formation of lymphatic vessels and that these vessels were capable of lymphatic flow. ETB blockade with the specific antagonist BQ788 inhibited matrix-metalloproteinase activation and dye transport within the lymphatic vessels, demonstrating that ETB is involved in the regulation of the growth of and in the formation of functional vessels upon activation by ET-1. Our results suggest that ET-1 is a lymphangiogenic mediator and that targeting pharmacologically ETB may be therapeutically exploited in a variety of diseases, including cancer.

Transport of Phage P22 DNA across the Cytoplasmic Membrane

ABSTRACT Although a great deal is known about the life cycle of bacteriophage P22, the mechanism of phage DNA transport into Salmonella is poorly understood. P22 DNA is initially ejected into the periplasmic space and subsequently transported into the host cytoplasm. Three phage-encoded proteins (gp16, gp20, and gp7) are coejected with the DNA. To test the hypothesis that one or more of these proteins mediate transport of the DNA across the cytoplasmic membrane, we purified gp16, gp20, and gp7 and analyzed their ability to associate with membranes and to facilitate DNA uptake into membrane vesicles in vitro. Membrane association experiments revealed that gp16 partitioned into the membrane fraction, while gp20 and gp7 remained in the soluble fraction. Moreover, the addition of gp16, but not gp7 or gp20, to liposomes preloaded with a fluorescent dye promoted release of the dye. Transport of 32P-labeled DNA into liposomes occurred only in the presence of gp16 and an artificially created membrane potential. Taken together, these results suggest that gp16 partitions into the cytoplasmic membrane and mediates the active transport of P22 DNA across the cytoplasmic membrane of Salmonella.

Examining the Vascular Pathway of Sweet Cherries Grafted onto Dwarfing Rootstocks

Dye transport through vascular pathways was examined in tissues surrounding the graft union of second-leaf, field-grown trees of `Lapins'/Gisela 5 (`Gi 5') (dwarfing) and `Lapins'/'Colt' (nondwarfing). Excavated, intact trees were allowed to take up xylemmobile dye via transpiration for 6 h before sectioning the tree into scion, graft union, and rootstock tissue. `Lapins'/'Gi 5' had a significantly larger stem cross-sectional area in the central graft union than did `Lapins'/'Colt'. Per unit cross section, dye transport of both `Lapins'/'Gi 5' and `Lapins'/'Colt' was significantly less in the graft union than in rootstock sections, with still less transported to scion tissues in `Lapins'/'Gi 5'. `Lapins'/'Gi 5' had a tendency to produce vascular elements oriented obliquely to the longitudinal axis of the tree. Dye was distributed more uniformly axially and radially across the graft union in `Lapins'/'Colt' than in `Lapins'/'Gi 5', with an apparent accumulation of dye in `Lapins'/'Gi 5' graft union. Xylem vessel diameters and vessel hydraulic diameters (VDh) were smaller overall in `Lapins'/'Gi 5' than in `Lapins'/'Colt'; however, graft unions in both had smaller VDh than did rootstock sections. These observations suggest reduced transport efficiency of xylem vessels in the graft union in `Lapins'/'Gi 5' may be due to smaller vessels, vascular abnormalities and/or increased amounts of callus and parenchyma tissue.