Production and properties of a laccase isozyme (FvLcc3) from the edible mushroom Flammulina velutipes, which is undetectable under the culture condition for fruiting body formation.

Extracellular laccase isozyme (FvLcc3) from the edible mushroom Flammulina velutipes was found to be undetectable under the culture condition for fruiting body formation. FvLcc3 was purified and determined to be an approximately 53-kDa monomeric protein. FvLcc3 showed the highest catalytic efficiency (kcat/Km) toward 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) followed by 2,6-dimethoxyphenol and guaiacol and did not oxidize 3,4-dihydroxy-l-phenylalanine and l-tyrosine.

Relationship between fruiting body development and extracellular laccase production in the edible mushroom Flammulina velutipes.

The biochemical mechanism underlying the development of fruiting bodies in Flammulina velutipes, an edible mushroom, was investigated using the YBLB colorimetric assay to distinguish between the normal strain (FVN-1) and the degenerate strain (FVD-1). In this assay, the color of the YBLB medium (blue-green) inoculated with FVN-1 exhibiting normal fruiting body development changed to yellow, while the color of the medium inoculated with FVD-1 changed to blue. In this study, we found that this color difference originated from extracellular laccase produced by FVN-1. Moreover, FVN-1 exhibited considerably higher extracellular laccase activity than FVD-1, under conditions facilitating fruiting body formation. Overall, these findings suggest that extracellular laccase is involved in the fruiting body development process in F. velutipes.

Double diabetes: possible but unpublished complication of insulin pump therapy.

"Double diabetes," which refers to the coexistence of type 1 and type 2 diabetes mellitus, is a newly coined term in the diabetic literature. Excessive weight gain and a family history of type 2 diabetes in a patient with type 1 diabetes are the possible major causes. We report a case of double diabetes in a 45-year-old patient with type 1 diabetes mellitus that developed after insulin pump therapy. Insulin pump therapy is a valuable method used in the management of type 1 diabetes mellitus that may provide life comfort. However, this comfort may result in excessive weight gain, which, when combined with a family history of type 2 diabetes mellitus, may predispose to double diabetes. Clinicians must consider this pattern during the use of insulin pump therapy in patients with type 1 diabetes.