To make more effective use of underutilized resources, acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were isolated from the skin of deep-sea redfish (Sebastes mentella) and characterized for their potential in commercial applications. The yield of ASC (47.5%) was lower compared to PSC (92.2%), but the purity of ASC was significantly higher. The intrinsic viscosity of ASC (15.9 dL/g) was greater than PSC (14.6 dL/g), indicating a higher average molecular weight of ASC on account of the high proportion of polymers of collagen. The denaturation temperatures of ASC and PSC were 16.1 and 15.7 degrees C, respectively, suggesting the triple helical structure of PSC was still predominant. The amino acid profiles of ASC and PSC were similar with lower imino acid content than most other species, which might be the reason for the lower denaturation temperature. SDS-PAGE and FTIR showed that both ASC and PSC were type I mainly with slight structure differences. ASC held its triple helical structure well, and possessed a higher extent of intermolecular cross-link. While the structure of PSC was changed slightly due to the loss of N- and C-terminus domains, the triple helical structure was still predominant as a result of the formation of more and/or stronger hydrogen bond.

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Non-heading Chinese cabbage (Brassica campestris L. ssp. chinensis Makino), an important vegetable crop in China, exhibits a typical sporophytic self-incompatibility (SI) system. To better understand the mechanism of SI response and identify potential candidate proteins involved in the SI system of this vegetable crop, the proteomic approach was taken to identify differential accumulating pistil proteins. Pistils were collected at 0 h and 2 h after self-pollination at anthesis in self-incompatible and compatible lines of non-heading Chinese cabbage, and total proteins were extracted and separated by two-dimensional gel electrophoresis (2-DE). A total of 25 protein spots that displayed differential abundance were identified by matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF/TOF MS) and peptide mass fingerprinting (PMF). Among them, 22 protein spots were confidently established. The mRNA levels of the corresponding genes were detected by quantitative RT-PCR. The 22 identified protein spots are involved in energy metabolism (four), protein biosynthesis (three), photosynthesis (six), stress response and defence (five), and protein degradation (four). Among these potential candidate proteins, UDP-sugar pyrophosphorylase could be involved in sucrose degradation to influence pollen germination and growth. Glutathione S-transferases could be involved in pollen maturation, and affect pollen fertility. Senescence-associated cysteine protease, which is related to programmed cell death, could be mainly related to self pollen recognition of non-heading Chinese cabbage. The study will contribute to further investigations of molecular mechanism of sporophytic SI in Brassicaceae.

In mammalian intestine, the passive entry of Ca 2+ into enterocytes via the transient receptor potential vanilloid channel type 6 (TRPV6) is recognized to be an important rate-limiting entry step in maintaining Ca 2+ homeostasis. There is, however, little information on the expression patterns of TRPV6 in the laying hen and therefore this study investigated TRPV6 localization and expression in different intestinal segments and kidney of laying hens during peak lay. Immunohistochemical analysis of the intestine indicated that TRPV6 was localized to the brush-border membranes of the duodenum, jejunum, ileum, cecum, and rectum. Expression was weaker in the rectum and little or no expression was found in crypt and goblet cells. In addition, TRPV6 mRNA was quantified amongst different intestinal segments and expression was highest in the duodenum and jejunum. Furthermore, western blotting indicated that the duodenum expressed the greatest amount of TRPV6 and the rectum the least with the other segments expressing intermediate levels. In the kidney, distinct immunopositive staining for TRPV6 was detected at the apical domain of the distal convoluted tubules (DCT) and medullary connecting tubules (CNT). Interestingly, distribution of TRPV6 extended to the proximal convoluted tubules (PCT), which is not generally implicated in active Ca 2+ transcellular reabsorption. Furthermore, the kidney expressed lower TRPV6 mRNA (P<0.05) and protein levels compared to duodenum possibly implicating an important role for the TRPV5 homolog in the kidney. In conclusion, the epithelial Ca 2+ channel TRPV6 is strongly expressed in the apical cells of the entire intestine and the renal tubules suggesting that active Ca 2+ transcellular transport plays a crucial role in dietary calcium (re)absorption in laying hens.