The present disclosure provides improved long uniform recombinant protein fibers with desirable physical traits. The present disclosure also provides compositions derived from the long uniform recombinant protein fibers.

The present invention relates to antibodies that bind to a polypeptide at an epitope in the amino acid sequence of SEQ ID NO: 1 (e.g., a sericin polypeptide). The invention also provides methods and kits using the antibodies of the invention. In some embodiments, the antibody binds to a polypeptide at an epitope in the amino add sequence of SEQ ID NO: 2. In some embodiments, the antibody binds to a polypeptide at an epitope in the amino add sequence of SEQ ID NO: 3. In some embodiments, the polypeptide is a sericin polypeptide (e.g., a sericin isoform 1B polypeptide). In a related aspect, the invention features a method for selectively detecting sericin in a sample.

The present invention relates to antibodies that bind to a polypeptide at an epitope in the amino acid sequence of SEQ ID NO: 1 (e.g., a sericin polypeptide). The invention also provides methods and kits using the antibodies of the invention. In some embodiments, the antibody binds to a polypeptide at an epitope in the amino add sequence of SEQ ID NO: 2. In some embodiments, the antibody binds to a polypeptide at an epitope in the amino add sequence of SEQ ID NO: 3. In some embodiments, the polypeptide is a sericin polypeptide (e.g., a sericin isoform 1B polypeptide). In a related aspect, the invention features a method for selectively detecting sericin in a sample.

Disclosed is a method of efficiently producing a long bagworm silk thread containing no contaminant while preventing a change in the spinning direction and the runaway of the bagworm from a rail, and alleviating a burden on the bagworm; and an apparatus for implementing the thread-producing method. Provided is an apparatus for producing a bagworm silk thread, having a movable rail having a width smaller than the maximum width between the right and left legs of a bagworm and configured to move in the longitudinal direction and to be able to hold with the legs of the bagworm; and a fixator configured to fix a bagworm, wherein the fixator is placed at a position such that the fixed bagworm can hold the movable rail.

Disclosed is a method of efficiently producing a long bagworm silk thread containing no contaminant while preventing a change in the spinning direction and the runaway of the bagworm from a rail, and alleviating a burden on the bagworm; and an apparatus for implementing the thread-producing method. Provided is an apparatus for producing a bagworm silk thread, having a movable rail having a width smaller than the maximum width between the right and left legs of a bagworm and configured to move in the longitudinal direction and to be able to hold with the legs of the bagworm; and a fixator configured to fix a bagworm, wherein the fixator is placed at a position such that the fixed bagworm can hold the movable rail.