https://www.selleckchem.com/products/td139.html Many species of aquatic worms, including members of the phyla Nemertea, Annelida, Platyhelminthes, and Xenacoelomorpha, can regenerate large parts of their body after amputation. In most species, cell proliferation plays key roles in the reconstruction of lost tissues. For example, in annelids and flatworms, inhibition of cell proliferation by irradiation or chemicals prevents regeneration. Cell proliferation also plays crucial roles in growth, body patterning (e.g., segmentation) and asexual reproduction in many groups of aquatic worms. Cell proliferation dynamics in these organisms can be studied using immunohistochemical detection of proteins expressed during proliferation-associated processes or by incorporation and labeling of thymidine analogues during DNA replication. In this chapter, we present protocols for labeling and quantifying cell proliferation by (a) antibody-based detection of either phosphorylated histone H3 during mitosis or proliferating cell nuclear antigen (PCNA) during S-phase, and (b) incorporation of two thymidine analogues, 5'-bromo-2'-deoxyuridine (BrdU) and 5'-ethynyl-2'-deoxyuridine (EdU), detected by immunohistochemistry or inorganic "click" chemistry, respectively. Although these protocols have been developed for whole mounts of small ( less then 2 cm) marine and freshwater worms, they can also be adapted for use in larger specimens or tissue sections.To provide a better understanding of the composition of the egg cell membrane, we describe a method in which proteins and peptides that are either naturally released by the egg or cleaved by sperm proteases can be collected, analyzed, and identified. Such molecules are captured and isolated from the surrounding seawater via biotinylation, before being concentrated by an affinity interaction and subsequently analyzed by western blotting and mass spectrometry.Immunoblotting analyses employing phospho-specific antibodies can help elucidate pote