Biocatalytic deuterium- and hydrogen-transfer using over-expressed ADH-'A': enhanced stereoselectivity and 2H-labeled chiral alcohols.

Employing the over-expressed highly organic solvent tolerant alcohol dehydrogenase ADH-'A' from Rhodococcus ruber DSM 44541, versatile building blocks, which were not accessible by the wild type catalyst, were obtained in > 99% e.e.; furthermore, employing d8-2-propanol as deuterium source, stereoselective biocatalytic deuterium transfer was made feasible to furnish enantiopure deuterium labeled sec-alcohols on a preparative scale employing a single enzyme.

Highly enantioselective sec-alkyl sulfatase activity of Sulfolobus acidocaldarius DSM 639.

[reaction: see text] rac-sec-Alkyl sulfate esters 1a-4a were resolved in high enantioselectivities with E-values up to >200 using whole cells of aerobically grown Sulfolobus acidocaldarius DSM 639. The stereochemical course of this biohydrolysis was shown to proceed with strict inversion of configuration; thus, the preferred (R)-enantiomers were converted into the corresponding (S)-sec-alcohols to furnish a homochiral product mixture.

Sophorolipids and their derivatives are lethal against human pancreatic cancer cells.

INTRODUCTION: We have previously demonstrated that sophorolipids, a class of easily chemoenzymatically modifiable glycolipids, possess anti-inflammatory effects in vitro and in vivo. Since glycolipids have been shown to have anticancer activity, we investigated the effects of sophorolipids and their derivatives against pancreatic cancer. MATERIALS AND METHODS: Human pancreatic carcinoma cells were treated with increasing concentrations of sophorolipid natural mixture or select derivatives (ethyl ester, methyl ester, ethyl ester monoacetate, ethyl ester diacetate, acidic sophorolipid [AS], lactonic sophorolipid diacetate [LSD]) for 24 h and assessed for cell necrosis (cytotoxicity-lactate dehydrogenase release). Controls consisted of cells treated with media or vehicle alone and sophorolipid treatment of peripheral blood mononuclear cells. RESULTS: Sophorolipids demonstrated anticancer activity against human pancreatic carcinoma cells. Natural mixture mediated consistent cytotoxicity at all doses tested (20 +/- 4%). However, methyl ester derivative mediated much greater levels of cytotoxicity (63 +/- 5%) compared with other derivatives (ethyl ester diacetate, 36 +/- 6%, ethyl ester monoacetate, 18 +/- 7%; P < 0.05). In contrast, LSD- and AS-mediated toxicity was inversely proportional with dose (LSD, 40.3% at 0.5 mg/mL, 3.4% at 2.0 mg/mL; AS, 49% at 0.5 mg/mL, 0% at 2.0 mg/mL). Sophorolipid treatment did not affect peripheral blood mononuclear cells at all doses tested. CONCLUSIONS: These results suggest that sophorolipids and select derivatives may be effective in treating human pancreatic cancer. Furthermore select derivatives may use different mechanisms toward this end. The ability to chemoenzymatically modify sophorolipids can provide effective lead compounds toward the treatment of pancreatic cancer.

Sophorolipids improve sepsis survival: effects of dosing and derivatives.

INTRODUCTION: Sophorolipids, a family of natural and easily chemo-enzymatically modified microbial glycolipids, are promising modulators of the immune response. We have previously demonstrated that sophorolipids mediate anti-inflammatory effects, including decreasing sepsis-related mortality at 36 h in vivo in a rat model of septic peritonitis and in vitro by decreasing nitric oxide and inflammatory cytokine production. Here we assessed the effect of sophorolipids on sepsis-related mortality when administered as a (1) single bolus versus sequential dosing and (2) natural mixture versus individual derivatives compared with vehicle alone. METHODS: Intra-abdominal sepsis was induced in male, Sprague Dawley rats, 200 to 240 g, via cecal ligation and puncture. Sophorolipids (5-750 mg/kg) or vehicle (ethanol/sucrose/physiological saline) were injected intravenously (i.v.) via tail vein or inferior vena cava at the end of the operation either as a single dose or sequentially (q24 h x 3 doses); natural mixture was compared with select sophorolipid derivatives (n = 10-15 per group). Sham-operated animals served as nonsepsis controls. Survival rates were compared at 1 through 6 d post sepsis induction and tissue was analyzed by histopathology. Significance was determined by Kruskal-Wallis analysis with Bonferroni adjustment and Student's t-test. RESULTS: Sophorolipid treatment at 5 mg/kg body weight improved survival in rats with cecal ligation and puncture-induced septic shock by 28% at 24 h and 42% at 72 h for single dose, 39% at 24 h and 26% at 72 h for sequential doses, and 23% overall survival for select sophorolipid derivatives when compared with vehicle control (P < 0.05 for sequential dosing). Toxicity was evident and dose-dependent with very high doses of sophorolipid (375-750 mg/kg body weight) with histopathology demonstrating interstitial and intra-alveolar edema with areas of microhemorrhage in pulmonary tissue when compared with vehicle controls (P < 0.05). No mortality was observed in sham operated controls at all doses tested. CONCLUSIONS: Administration of sophorolipids after induction of intra-abdominal sepsis improves survival. The demonstration that sophorolipids can reduce sepsis-related mortality with different dosing regimens and derivatives provides continuing evidence toward a promising new therapy. Toxicity is evident at 75 to 150x the therapeutic dose in septic animals.

Highly enantioselective stereo-inverting sec-alkylsulfatase activity of hyperthermophilic Archaea.

rac-sec-Alkyl sulfate esters 1a-8a were resolved in low to excellent enantioselectivities with E-values up to >200 using whole cells of aerobically-grown hyperthermophilic sulfur-metabolizers, such as Sulfolobus solfataricus DSM 1617, Sulfolobus shibatae DSM 5389 and, most notably, Sulfolobus acidocaldarius DSM 639. Significantly enhanced selectivities were obtained using cells grown on sucrose-enriched Brock-medium. The stereochemical course of this biohydrolysis was shown to proceed with strict inversion of configuration, thus the preferred (R)-enantiomers were converted into the corresponding (S)-sec-alcohols to furnish a homochiral product mixture.