Trichobilharzia regenti which are capable of keratin and collagen degradation. Experiments with laboratory prepared recombinant form of the cysteine peptidase cathepsin B2 of "T. regenti" (TrCB2) confirmed its ability to cleave skin proteins (collagen, keratin and elastin). After penetration the skin, cercariae transform to schistosomula and start a migration through the host’s body. They avoid penetration into blood capillaries and rather prefer entering peripheral nerves in host’s limbs. Schistosomula are found in peripheral nerves of ducks and mice as soon as 1.5 and 1 day post infection (DPI), respectively. In both types of hosts, schistosomula exhibit a high affinity to the central
Myosin head although some forms have a globular region in their C-terminal. There are many cell-specific isoforms of myosin heavy chains, coded for by a multi-gene family. Myosin interacts with actin to convert chemical energy, in the form of ATP, to mechanical energy. The 3-D structure of the head portion of myosin has been determined and a model for actin-myosin complex has been constructed. The globular head is well conserved, and is key to contraction. Muscle contraction results from an attachment–detachment cycle between the myosin heads extending from myosin filaments and the sites on actin filaments. The myosin head first attaches to