木瓜蛋白酶水解珠蚌制备肽钙及其红外光谱分析

以木瓜蛋白酶酶解珠蚌肉制备的活性肽为原料,研究珠蚌活性肽与钙离子的螯合新工艺,并对螯合产物进行红外光谱分析。研究表明:珠蚌活性肽与钙离子的最佳螯合工艺为螯合时间45min、温度35℃、肽钙比4.5:1、pH9.5、固液比1:30,此条件下,肽钙螯合率为31.47%。红外光谱扫描显示,肽的螯合产物在1418.7cm-1出现了羧酸盐的特征峰,在3386.8cm-1处出现了铵盐的特征峰,表明珠蚌活性肽与钙离子螯合物的生成。     

贻贝酶解物对羟自由基清除作用的试验研究

通过测定贻贝酶解物对离体实验系统（Fenton体系）产生的羟自由基的清除效果，从胰蛋白酶、木瓜蛋白酶、胃蛋白酶3种酶中筛选出木瓜蛋白酶和胰蛋白酶作为酶解贻贝制备具有较高清除羟自由基活性酶解物的理想水解酶；并通过正交实验L9（3^4）对2种酶的水解条件进行优化。结果表明木瓜蛋白酶在温度60℃、酶解时间15min、DH7．5、酶质量分数1．00％的水解条件下，酶解物对羟自由基的清除效果最佳；胰蛋白酶在温度45℃、酶解时间35min,pH8，5、酶质量分数0．75％的水解条件下，酶解物对羟自由基清除效果最佳。木瓜蛋白酶酶解物在最大洗脱峰时有最大羟基自由基清除率峰，清除率为76．15％，在最大峰处酶解物中活性肽的分子量为1．4kDa；胰蛋白酶酶解物在最大洗脱峰时也有最大羟基自由基清除率峰，其清除率为69．13％，该峰处活性肽的分子量也为1．4kDa。     

Estimation of Whole Volume of Green Shelled Mussels using their Geometrical Attributes Obtained from Image Analysis

Aquacultured green shelled mussels are an important export product of New Zealand. Using image analysis, several geometrical attributes of live mussels were measured. The volume of individual live mussels was estimated by several methods. When the cubic splines method was applied to top and side view images, volume was estimated with a coefficient of determination of R² = 0.97. When only the top view area was used, the R² decreased to 0.94. When the side view area was also included and empirical equations were fitted to estimate whole volume, the R² was 0.97. When measured length, width, and thickness were used to estimate volume, the R² was 0.95. There was a wide variation of the measured density of live mussels (1.05–1.27 g/cm³). Also, the condition index of the live mussels varied between 48 and 95. There was no correlation between the size of the mussel and its condition index. The mass of the mussel meat could not be accurately predicted by using the whole mass of the live mussel.     

通过化工产品工程开发可持续的技术来控制斑纹蚌种群

The zebra mussel is an important aquatic pest that causes great damage to freshwater-dependent industries, due to biofouling. The main goal of the project discussed here is to develop improved solutions to control this species. Three approaches have been explored in an attempt to design innovative application strategies for existing biocides： （i） encapsulation of toxins; （ii） combination of toxins; （iii） investigation of the seasonal variation of the species＇ tolerance to toxins. In this paper, the principles behind these approaches and the major results on each topic are presented. The benefits of adopting a chemical product engineering approach in conducting this project are also discussed.     

Dreissenid mussels from the Great Lakes contain elevated thiaminase activity

We examined thiaminase activity in dreissenid mussels collected at different depths and seasons, and from various locations in Lakes Michigan, Ontario, and Huron. Here we present evidence that two dreissenid mussel species (Dreissena bugensis and D. polymorpha) contain thiaminase activity that is 5–100 fold greater than observed in Great Lakes fishes. Thiaminase activity in zebra mussels ranged from 10,600 to 47,900 pmol g^− 1·min^− 1 and activities in quagga mussels ranged from 19,500 to 223,800 pmol g^− 1·min^− 1. Activity in the mussels was greatest in spring, less in summer, and least in fall. Additionally, we observed greater thiaminase activity in dreissenid mussels collected at shallow depths compared to mussels collected at deeper depths. Dreissenids constitute a significant and previously unknown pool of thiaminase in the Great Lakes food web compared to other known sources of this thiamine (vitamin B₁)-degrading enzyme. Thiaminase in forage fish of the Great Lakes has been causally linked to thiamine deficiency in salmonines. We currently do not know whether linkages exist between thiaminase activities observed in dreissenids and the thiaminase activities in higher trophic levels of the Great Lakes food web. However, the extreme thiaminase activities observed in dreissenids from the Great Lakes may represent a serious unanticipated negative effect of these exotic species on Great Lakes ecosystems.     

Dreissenidae in Lake Ontario: Impact Assessment at the Whole Lake and Bay of Quinte Spatial Scales

The total abundance in Lake Ontario of Dreissena polymorpha (Dreissenidae), the zebra mussel, and D. bugensis (Dreissenidae), the quagga mussel, was calculated by aggregating data from several surveys carried out in 1991 to 94. In 1993, there were between 3.0 × 10 and 8.7 × 10¹² Dreissenidae mussels in Lake Ontario. A filtration model was contructed using depth-specific density estimates, a digital bathymetric map of the lake, and literature estimates of clearance rates for individual mussels. With reasonable estimates of both densities and filtration rates, the mean, area-weighted, turnover time of Lake Ontario water by dreissenid mussels was about 1 year. At the smaller spatial scale of the Bay of Quinte, the same model estimated turnover times of 0.05, 0.2, and 10 days for the lower, middle, and upper areas of the bay, respectively. Depth-specific secondary production estimates for dreissenids, combined with literature estimates of net primary production and energy transfer efficiencies, were incorporated into a food demand model that indicated about 1.25 gC/y mussel of food in Lake Ontario and a consumption efficiency of 50%. At the smaller spatial scale of the Bay of Quinte, the same model estimated one to two orders of magnitude less food per mussel and 62%, 130% and 115% consumption efficiency for the lower, middle and upper areas of the bay, respectively. Dreissenidae mussels may not have a huge impact on the Lake Ontario food web when considered at a whole-lake scale, but their potentially striking impact at the smaller spatial scale of embayments like the Bay of Quinte indicate that they may be locally important. When these effects are aggregated across several sub-systems, Dreissenidae mussels may have unpredictable, larger scale effects in the Lake Ontario ecosystem as a whole.     

Bioinspired Conductive Silk Microfiber Integrated Bioelectronic for Diagnosis and Wound Healing in Diabetes

Ideal epidermal bioelectronics can be used not only for long-term detection of physiological signals for disease diagnosis but also for chronic disease treatment. Silk, an animal-derived fiber with good biocompatibility and skin-affinity, is widely used in flexible bioelectronics. However, silk fibers are insulating. In this study, ultralong conductive silk microfibers (mSFs) are fabricated by extracting mSF from raw silk using a bioinspired extraction-protection process with the assistance of polydopamine, followed by deposition of poly(3,4-ethylenedioxythiophene) (PEDOT) on its surface. The conductive mSFs are produced and used to fabricate a conductive flexible silk fibroin patch, which is used as a conformable bioelectronic for monitoring physiological signals. In addition, as the conductive mSF possessed anti-oxidative activity, the patch exhibits excellent performance in chronic diabetic wound healing by reducing inflammation and regulating oxidative stress. Thus, this bioinspired strategy produces conductive silk fibers that can be used as biocompatible building blocks, opening new avenues for employing passive silk as an active component in the design of epidermal wound repair biomaterials and next-generation flexible epidermal bioelectronics.     

Mussel‐Inspired Adhesive and Conductive Hydrogel with Long‐Lasting Moisture and Extreme Temperature Tolerance

Conductive hydrogels are a promising class of materials to design bioelectronics for new technological interfaces with human body, which are required to work for a long‐term or under extreme environment. Traditional hydrogels are limited in short‐term usage under room temperature, as it is difficult to retain water under cold or hot environment. Inspired by the antifreezing/antiheating behaviors from nature, and based on mussel chemistry, an adhesive and conductive hydrogel is developed with long‐lasting moisture lock‐in capability and extreme temperature tolerance, which is formed in a binary‐solvent system composed of water and glycerol. Polydopamine (PDA)‐decorated carbon nanotubes (CNTs) are incorporated into the hydrogel, which assign conductivity to the hydrogel and serve as nanoreinforcements to enhance the mechanical properties of the hydrogel. The catechol groups on PDA and viscous glycerol endow the hydrogel with high tissue adhesiveness. Particularly, the hydrogel is thermal tolerant to maintain all the properties under extreme wide tempreature spectrum (?20 or 60 °C) or stored for a long term. In summary, this mussel‐inspired hydrogel is a promising material for self‐adhesive bioelectronics to detect biosignals in cold or hot environments, and also as a dressing to protect skin from injuries related to frostbites or burns.     

Mussel‐Inspired Contact‐Active Antibacterial Hydrogel with High Cell Affinity,Toughness, and Recoverability

Antibacterial hydrogel has received extensive attention in soft tissue repair, especially preventing infections those associated with impaired wound healing. However, it is challenging in developing an inherent antibacterial hydrogel integrating with excellent cell affinity and superior mechanical properties. Inspired by the mussel adhesion chemistry, a contact‐active antibacterial hydrogel is proposed by copolymerization of methacrylamide dopamine (MADA) and 2‐(dimethylamino)ethyl methacrylate and forming an interpenetrated network with quaternized chitosan. The reactive catechol groups of MADA endow the hydrogel with contact intensified bactericidal activity, because it increases the exposure of bacterial cells to the positively charged groups of the hydrogel and strengthens the bactericidal effect. MADA also maintains the good adhesion of fibroblasts to the hydrogel. Moreover, the hybrid chemical and physical cross‐links inner the hydrogel network makes the hydrogel strong and tough with good recoverability. In vitro and in vivo tests demonstrate that this tough and contact‐active antibacterial hydrogel is a promising material to fulfill the dual functions of promoting tissue regeneration and preventing bacterial infection for wound‐healing applications.     

海洋生物及其粘附机理——微生物、小型海藻、巨型海藻、贻贝

主要介绍海洋生物中微生物、小型海藻、巨型海藻、贻贝等的粘附机理 ,这对于应用于外科和牙科领域的仿生胶粘剂及海洋防污涂层的研制有着重要的意义