Abstract: The present invention provides a method for producing a composition containing 2-acyl-lysophosphatidylserine, including (a) a step of obtaining a composition containing phosphatidylserine by allowing phospholipase D to act on a raw material containing phosphatidylcholine in the presence of serine and (b) a step of obtaining a composition containing 2-acyl-lysophosphatidylserine by allowing phospholipase A1 to act on the composition containing phosphatidylserine in the presence of one or more additives selected from the group consisting of the following (I), (II), and (III), in which (I) one or more salts selected from the group consisting of sulfate salts, phosphate salts, nitrate salts, citrate salts, and tartarate salts of monovalent cations, (II) a gum, and (III) an emulsifier.

Abstract: The present invention provides a method for producing a composition containing 2-acyl-lysophosphatidylserine, including (a) a step of obtaining a composition containing phosphatidylserine by allowing phospholipase D to act on a raw material containing phosphatidylcholine in the presence of serine and (b) a step of obtaining a composition containing 2-acyl-lysophosphatidylserine by allowing phospholipase A1 to act on the composition containing phosphatidylserine in the presence of one or more additives selected from the group consisting of the following (I), (II), and (III), in which (I) one or more salts selected from the group consisting of sulfate salts, phosphate salts, nitrate salts, citrate salts, and tartarate salts of monovalent cations, (II) a gum, and (III) an emulsifier.

Abstract: Mesophilic xylanases derived from Acremonium cellulolyticus. A mesophilic xylanase I, derived from the mold Acremonium cellulolyticus, capable of non-specifically hydrolyzing xylan mainly into xylose, xylobiose and xylotriose, having an optimal pH at 3.5 and an optimal temperature for action at 55.degree. C. as determined by saccharifying activity for soluble xylan as a substrate and a molecular weight of 30,000 as determined by SDS-polyacrylamide gel electrophoresis. A mesophilic xylanase II having an optimal pH a 3.8, an optimal temperature for action at 55.degree. C. and a molecular weight of 25,500. A mesophilic xylanase III having an optimal pH at 3.5, an optimal temperature for action at 50.degree. C. and a molecular weight of 33,500.

Abstract: An optical head comprises a fixed optical casing and a movable optical casing accommodating a deflecting mirror and an objective lens which moves separately from the deflecting mirror. Windows are inserted in the boundary between the interior and exterior of an optical path to cover a light-exposed area of an optical system so as to prevent dust from entering into the optical casings. Each window is simple in its construction and makes a slight angle with a plane perpendicular to the optical axis of the optical system so that the windows do not become dusty. Each window can be coated with a conductive thin film which is grounded through a conductive area of each optical casing.