Effect of 7β‐hydroxycholesterol on growth and membrane composition of Mycoplasma capricolum

Abstract

7/%OH cholesterol in a cholesterol rich growth medium (5-10 pg/ml) extended the lag period and slowed down the growth rate of Mycoplasma cupricolum cells. In a cholesterol poor medium (0.5 fig/ml) inadequate to support growth, 7j%OH cholesterol exerts a synergistic effect on growth. The 78-OH cholesterol was incorporated unchanged from the growth medium and could be recovered exclusively in the membrane fraction. The incorporation of the 78-OH cholesterol has no effect on the total phospholipid content but the DPG to PG ratio was markedly decreased. Exchange studies with lipid vesicles revealed that whereas most of the cholesterol underwent exchange, only about 20% of the 7/?-OH cholesterol was exchanged.

Electrospray ionization mass spectrometry of AZT H‐phosphonates conjugated with steroids

“…The H ‐phosphonates 6a and 6b , conjugated with 3 β ‐cholesterol and diosgenin, respectively, have been synthesized in our laboratory. As the conjugating moieties, 3 β ‐cholesterol and diosgenin were chosen for their lipophilic character, lymphocyte membrane affinity and the ability of binding to low density lipoprotein 7–9. Here, the electrospray ionization (ESI) mass fragmentation pathways of compounds 6a and 6b are discussed in detail.…”

Synthesis and Cytotoxic Activity of Steroidal Phosphorothioate,Phosphoroselenoate, and Phosphate Derivatives Conjugated with 3-Azido-3-Deoxythymidine

“…In order to determine whether the activity can be increased, some steroid lipids conjugated with AZT were prepared to improve the activity of prodrugs, because of their lipophilic character, lymphocyte membrane affinity and the ability of binding to low density lipoprotein [16]. In the continuation of our work [17,18], we report the synthesis of novel steroidal phosphorothioate, phosphoroselenoate, and phosphate derivatives conjugated with AZT, and the cytotoxic activity against breast cancer MCF-7 in vitro by the standard MTT method in this paper.…”

Characteristic Fragmentation Behavior of Steroidal Phosphor‐ amidate Conjugates in Electrospray Ionization Tandem Mass Spectrometry

“…[7][8][9][10][11][12][13] Steroidal conjugates possess the lipophilicity, membrane penetration, lymphocyte membrane affinity and the ability of binding to low density lipoprotein. [14][15][16] Therefore, a series of steroidal H-phosphonates and glycophosphodiesters were previously synthesized in our laboratory. [17][18][19] The corresponding phosphates, phosphorothionates, phosphoroselenoates, and phosphoramidates could be easily obtained from the corresponding H-phosphonates by oxidation and conjugated with amino acids or peptides.…”