Protein Sponge Research Articles

Marine Sponges, Other Animal Food, and Nonfood Items Found in Digestive Tracts of the Herbivorous Marine Turtle Chelonia mydas in Hawai'i

Although the usual diet of Chelonia mydas comes from algae and sea grasses (plant material), animal material has been found in samples taken over the past 35 yr. The small black-brown protein sponge Chondrosia chucalla resembles the alga Codium arabicum in size, color, and texture, and both grow next to each other on the reefs. We hypothesize that turtles are actively seeking and eating these sponges and not mistaking them for C. arabicum. Both protein and silica sponges occur in the diet of Chelonia, but only 6.8% of the time are eaten in addition to their usual plant diet. Thirty different kinds of other animals were found in the samples, including Cnidaria, Mollusca, Crustacea, Insecta, Echinodermata, squid, fish, tumor flesh, and other animals but in low frequency (5%). Most of the miscellaneous nonfood debris items were terrestrial leaves, plastic, paper, string, fibers, hair, and paint chips but also in low frequency (<7%). Among animal food items known to have nutritional value, the protein sponge C. chucalla could be contributing an important nutritive factor, but this needs further research.

The DOCK Protein Sponge Binds to ELMO and Functions in Drosophila Embryonic CNS Development

Cell morphogenesis, which requires rearrangement of the actin cytoskeleton, is essential to coordinate the development of tissues such as the musculature and nervous system during normal embryonic development. One class of signaling proteins that regulate actin cytoskeletal rearrangement is the evolutionarily conserved CDM (C. elegans Ced-5, human DOCK180, Drosophila Myoblast city, or Mbc) family of proteins, which function as unconventional guanine nucleotide exchange factors for the small GTPase Rac. This CDM-Rac protein complex is sufficient for Rac activation, but is enhanced upon the association of CDM proteins with the ELMO/Ced-12 family of proteins. We identified and characterized the role of Drosophila Sponge (Spg), the vertebrate DOCK3/DOCK4 counterpart as an ELMO-interacting protein. Our analysis shows Spg mRNA and protein is expressed in the visceral musculature and developing nervous system, suggesting a role for Spg in later embryogenesis. As maternal null mutants of spg die early in development, we utilized genetic interaction analysis to uncover the role of Spg in central nervous system (CNS) development. Consistent with its role in ELMO-dependent pathways, we found genetic interactions with spg and elmo mutants exhibited aberrant axonal defects. In addition, our data suggests Ncad may be responsible for recruiting Spg to the membrane, possibly in CNS development. Our findings not only characterize the role of a new DOCK family member, but help to further understand the role of signaling downstream of N-cadherin in neuronal development.

Tissue-engineering nerve repairs pelvic autonomic nerve defects in Beagle dogs

To investigate the outcome of repairing pelvic autonomic nerve defects with the tissue-engineered nerve, in order to provide a new method and experimental evidence for solving sexual disturbance induced by pelvic autonomic nerve injury after radical resection of rectal carcinoma. Bone marrow stromal cells (BMSCs) were purified with density gradient centrifugation. A 10 mm defect of hypogastric nerve was created in 9 Beagle dogs and the 18 hypogastric nerves were randomly divided into three groups. Group A: nerve defects bridged with copolymer of lactic and glycolic acids (PLGA) tube containing BMSCs and collagen protein sponge. Group B: with PLGA tube only containing collagen protein sponge. Group C: with autologous nerve graft. The effect of nerve recovery was evaluated by morphology, HE staining, neurofilament immunohistochemistry staining, electron microscope scanning and measurement quantity of new axon 12 weeks after the transplantation. Twelve weeks after the transplantation, degradation of PLGA tubes showed in group A and group B. The nerves regenerated through defect area to distal end. The density of regeneration nerve fiber in group A and group C were better than that in group B. The difference was significant between group A or group C and group B (P<0.05), and no significant difference was observed between group A and group C(P>0.05). Tissue-engineered nerve, which is constructed by BMSCs mixed with collagen protein sponge and PLGA tube, can be used to bridge and repair the pelvic autonomic nerve defect.

Application of neural stem cells in tissue-engineered artificial nerve

To observe the curative effect of neural stem cells (NSCs), which are used in tissue-engineered artificial nerve, on repairing rabbit 10-mm facial nerve defects. Thirty-six Oryctolagus cuniculi were randomly divided into three groups (each group with 12 Oryctolagus cuniculi). In group A, chitosan conduit, collagen protein sponge, nerve growth factor (NGF), and NSCs were used. In group B, chitosan conduit, collagen sponge, and NGF were used. In group C, nerve autograft was performed. Electrophysiologic detection, histologic observation, and BrdU and S100 immunohistochemical examination were performed 12 weeks after operation. All observation items in group A were better than those in group B (P < 0.01), and there were no significant differences between group A and group C (P > 0.05). NSCs may be served as seed cells of peripheral nerve tissue engineering and be used in artificial nerve to repair facial nerve defects.

Application of 2‐D free‐flow electrophoresis/RP‐HPLC for proteomic analysis of human plasma depleted of multi high‐abundance proteins

Free-flow electrophoresis (FFE) and rapid (6 min) RP-HPLC was used to fractionate human citrate-treated plasma. Prior to analysis, the six most abundant proteins in plasma were removed by immunoaffinity chromatography; both depleted plasma and the fraction containing the six abundant proteins depleted were taken for MS-based analysis. Fractionated proteins were digested with trypsin and the generated peptides were subjected to MS-based peptide sequencing. To date, 78 plasma proteins have been unambiguously identified by manual validation from 16% (15/96 FFE total fractions) of the collected FFE pools; 55 identifications were based on > or = 2 tryptic peptides and 23 using single peptides. The molecular weight range of proteins and peptides isolated by this method ranged from approximately 190 K (e.g., Complement C3 and C4) to approximately 4-6 K (e.g., CRISPP and Apolipoprotein C1). This FFE/RP-HPLC approach reveals low-abundance proteins and peptides (e.g., L-Selectin approximately 17 ng/mL and the cancer-associated SCM-recognition, immunodefense suppression, and serine protease protection peptide (CRISPP) at approximately 0.5-1 ng/mL), where CRISPP was found in association with alpha-1-antitrypsin as a non-covalent complex, in the fraction containing the depleted high-abundance proteins. In contrast to shotgun proteomic approaches, the FFE/RP-HPLC method described here allows the identification of potentially interesting peptides to be traced back to their protein of origin, and for the first time, has confirmed the "protein sponge" hypothesis where the 35 residue CRISPP polypeptide is non-covalently complexed with the major circulating plasma protein alpha-1-antitrypsin.