Biosynthesis-inspired deracemizative production of d-luciferin by combining luciferase and thioesterase.

Due to the strict enantioselectivity of firefly luciferase, only d-luciferin can be used as a substrate for bioluminescence reactions. Unfortunately, luciferin racemizes easily and accumulation of nonluminous l-luciferin has negative influences on the light emitting reaction. Thus, maintaining the enantiopurity of luciferin in the reaction mixture is one of the most important demands in bioluminescence applications using firefly luciferase. In fireflies, however, l-luciferin is the biosynthetic precursor of d-luciferin, which is produced from the L-form undergoing deracemization. This deracemization consists of three successive reactions: l-enantioselective thioesterification by luciferase, in situ epimerization, and hydrolysis by thioesterase. In this work, we introduce a deracemizative luminescence system inspired by the biosynthetic pathway of d-luciferin using a combination of firefly luciferase from Luciola cruciata (LUC-G) and fatty acyl-CoA thioesterase II from Escherichia coli (TESB). The enzymatic reaction property analysis indicated the importance of the concentration balance between LUC-G and TESB for efficient d-luciferin production and light emission. Using this deracemizative luminescence system, a highly sensitive quantitative analysis method for l-cysteine was constructed. This LUC-G-TESB combination system can improve bioanalysis applications using the firefly bioluminescence reaction by efficient deracemization of D-luciferin.

[A case of cystic maculopathy during paclitaxel therapy].

BACKGROUND: Paclitaxel, one of the taxanes, has been used to treat malignant tumors such as breast cancer. It is known to cause cystic maculopathy as an unusual ocular side effect. Here, we describe the clinical features of a patient who suffered cystic maculopathy during paclitaxel therapy. CASE: A 62-year-old woman complained of visual disturbances in both eyes after receiving paclitaxel treatment of six months for metastatic breast cancer. Because cystic maculopathy was discovered during observation, and the paclitaxel therapy was discontinued. After about six weeks of acetazolamide administration, the cystic maculopathy disappeared and visual acuity had recovered. CONCLUSION: Paclitaxel treated patients should be followed carefully for ophthalmic complications, especially cystic maculopathy.

Late-onset laser in situ keratomileusis (LASIK) flap dehiscence during retinal detachment surgery.

PURPOSE: To report a case of laser in situ keratomileusis (LASIK) flap dehiscence during retinal detachment surgery 7 months after uneventful refractive surgery. DESIGN: Interventional case report. METHODS: A 47-year-old man noticed a defect of the upper visual field in his right eye 7 months after a LASIK procedure. The fundus showed rhegmatogenous retinal detachment, and a scleral buckling procedure was performed. During the buckling procedure, the corneal flap became detached. RESULTS: At completion of the buckling procedure, the detached corneal flap was carefully raised and the exposed corneal stroma was cleansed of any residual epithelial cells or red blood cells with irrigation using balanced salt solution. One day after the operation, the LASIK flap was repositioned, the cornea had cleared, and the retina was reattached. CONCLUSIONS: As LASIK increases in popularity, the complication we have reported may become more common. We suggest that a retinal detachment surgery should be performed with careful avoidance of corneal trauma even if a long time has passed since the LASIK procedure.