Side-chain oxysterols, such as 25-hydroxycholesterol (25-HC), are key regulators of cholesterol homeostasis. New evidence suggests that the alteration of membrane structure by 25-HC contributes to its regulatory effects. We have examined the role of oxysterol membrane effects on cholesterol accessibility within the membrane using perfringolysin O (PFO), a cholesterol-dependent cytolysin that se...

Side chain oxysterols are cholesterol derivatives thought to signal the abundance of cell cholesterol to homeostatic effector proteins. Here, we investigated how plasma membrane (PM) cholesterol might regulate 27-hydroxycholesterol (HC) biosynthesis in cultured fibroblasts. We showed that PM cholesterol was a major substrate for 27-HC production. Biosynthesis commenced within minutes of loading...

Tetanus toxin (TeTx) is the protein, synthesized by the anaerobic bacteria Clostridium tetani, which causes tetanus disease. TeTx gains entry into target cells by means of its interaction with lipid rafts, which are membrane domains enriched in sphingomyelin and cholesterol. However, the exact mechanism of host membrane binding remains to be fully established. In the present study we used the r...

Cope's gray treefrog, Hyla chrysoscelis,is a freeze-tolerant anuran which accumulates and distributes glycerol as a cryoprotectant before freezing. We hypothesize that HC-3, an aquaglyceroporin member of the MIP family of water pores, may play an important role in the process of freeze tolerance by mediating transmembrane passage of glycerol and water during cold-acclimation. The objectives of ...

A hollow-core anti-resonant fiber (HC-ARF) design based on hybrid silica/silicon cladding is proposed for single-polarization, single-mode and high birefringence. We show that by adding silicon layers in a semi-nested HC-ARF, one of the polarization states can be strongly suppressed while simultaneously maintaining low propagation loss other states, birefiringence. The optimized HC-ARF exhibits...

Hydrocarbons are prone to bacterial and fungal contamination. Bacteria and fungi live and proliferate in water droplets within the fuels and on surfaces surrounding them. This can cause corrosion in oil exploration and production, clogging of fuel lines in aviation and higher emissions in diesel combustion engines to state few examples. State-of-the-art is the addition of biocides to fuels, whi...

The principal host cell of H. capsulatum (Hc) is the M phi within which the pathogenic yeast phase of the fungus multiplies during active disease. The initial interaction between Hc yeasts and M phi therefore is a crucial step in the pathogenesis of histoplasmosis. In the present study, we have identified the major receptor mechanism that mediates the attachment of unopsonized Hc yeasts to huma...

Petroleum hydrocarbons are important energy resources used by industry and in our daily life, whose production contributes highly to environmental pollution. To control such risk, bioremediation constitutes an environmentally friendly alternative technology that has been established and applied. It constitutes the primary mechanism for the elimination of hydrocarbons from contaminated sites by ...