• Journal of Applied Biological Chemistry
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• v.59 no.4
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• pp.289-298
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• 2016

FK506 hyper-yielding mutant, called the TCM8594 strain, was made from Streptomyces tsukubaensis NRRL 18488 by mutagenesis using N-methyl-N'-nitro-N-nitrosoguanidine, ultraviolet irradiation, and FK506 sequential resistance selection. FK506 production by the TCM8594 strain improved 45.1-fold ($505.4{\mu}g/mL$) compared to that of S. tsukubaensis NRRL 18488 ($11.2{\mu}g/mL$). Among the five substrates, wheat bran was selected as the best solid substrate to produce optimum quantities of FK506 ($382.7{\mu}g/g$ substrate) under solid-state fermentation, and the process parameters affecting FK506 production were optimized. Maximum FK506 yield ($897.4{\mu}g/g$ substrate) was achieved by optimizing process parameters, such as wheat bran with 5 % (w/w) dextrin and yeast extract as additional nutrients, 70 % (v/w) initial solid substrate moisture content, initial medium pH of 7.2, $30^{\circ}C$ incubation temperature, inoculum level that was 10 % (v/w) of the cell mass equivalent, and a 10 day incubation. The results showed an overall 234 % increase in FK506 production after optimizing the process parameters.

• Archives of Pharmacal Research
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• v.27 no.8
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• pp.878-883
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• 2004

Tacrolimus (FK506), which is isolated from Streptomyces tsukubaensis, is a new potent immu-nosuppressant. Because of poor solubility in water, the conventional intravenous dosage forms of tacrolimus contain surfactants such as cremophor EL (BASF Wyandotte Co.) or hydroge-nated polyoxy 60 castor oil (HCO-60) which may cause adverse effects. This study relates to a polymer-tacrolimus conjugate, which can be dissolved in water, formed by chemically binding the sparingly soluble drug, tacrolimus, with the water soluble polymer, methoxypoly(ethylene glycol) (mPEG). Water soluble tacrolimus-mPEG conjugates have been synthesized and shown to be function in vitro as prodrugs. These conjugates are in the form of an ester wherein the 24-, 32- or 24,32-positions are esterified. The desired 24-, 32- or 24,32-esterified com-pounds were obtained by initially acylating of tacrolimus with iodoacetic acid at the 24-,32-, or 24,32-positions and then reacting the resulting acylated tacrolimus with a mPEG in the pres-ence of a base such as sodium bicarbonate. These conjugates were converted again into tac-rolimus by the action of enzymes in human liver homogenate, and the half-lives of the conjugates are approximately 10 min in the homogenate, indicating that the esterified tacroli-mus derivatives may be practically applicable as a prod rug for the immunosuppressant.

• Journal of Marine Bioscience and Biotechnology
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• v.14 no.1
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• pp.33-42
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• 2022

Tacrolimus, a type of macrolide produced by Streptomyces tsukubaensis, is widely used as an immunosuppressant. However, continuous exposure to tacrolimus causes oxidative stress in normal cells, ultimately inducing cell injury. Therefore, this study investigated whether luthione, a reduced glutathione, could inhibit tacrolimus-induced cytotoxicity in olive flounder (hirame) natural embryo (HINAE) cells. According to the results, luthione significantly inhibited tacrolimus-induced reduction in cell viability in a concentration-dependent manner. Additinally, although luthione unaffected autophagy by tacrolimus, tacrolimus-induced apoptosis was significantly suppressed in the presence of luthione. Luthione also markedly blocked DNA damage in tacrolimus-treated HINAE cells, associated with the inhibition of reactive oxygen species (ROS) generation. Additionally, tacrolimus cytotoxicity in HINAE cells was correlated with increased inflammatory response, also attenuated by luthione. Collectively, these results show that at least luthione protects HINAE cells against tacrolimus-induced DNA damage, apoptosis, and inflammation, but not autophagy, by scavenging ROS. Although additional in-vivo studies are required, this study's results can be used as a basis for utilizing luthione to reduce the toxicity of fish cells caused by excessive immune responses.