Release Model of Water-soluble Chitosan Nanoparticles for Protein Delivery

[Objective] The experiment aimed to explore release rule of water-soluble chitosan (WSC) in vitro. [Method]The bovine serum albumin(BSA) was taken as a model protein drug and some existing release models such as Kinetics model, Gompertz model, Weibull model, Higuchi model and Logistic model were used to fit the BSA release profile from WSC carriers. [Result] Except Higuchi model and Logistic model, other models could fit BSA release profile better. [Conclusion] Gompertz two-order kinetics model could fit the release of WSC nano-particles better and model parameters had practical physical meaning.

Palatability of Water-Soluble Extracts of Protein Sources and Replacement of Fishmeal by a Selected Mixture of Protein Sources for Juvenile Turbot(Scophthalmus maximus)

Poor palatability is a limiting factor for replacing fishmeal with other protein sources in aquaculture. The water-soluble molecules with low molecular weights are the major determinants of the palatability of diets. The present study was conducted to investigate the palatability of water-soluble extracts from single protein source(single extract pellets) and the mixture of these extracts with different proportions(blended extract pellets) in juvenile turbot(Scophthalmus maximus). Then according to the palatability of blended extract pellets, an optimal mixture proportion was selected, and a new protein source made from raw protein materials with the selected proportion was formulated to replace fishmeal. Summarily, the palatability of single extract pellets for turbot was descendent from fishmeal to pet-food grade poultry by-product meal, wheat gluten meal, soybean meal, peanut meal, meat and bone meal, and corn gluten meal. Subsequently, according to the palatability of single extract pellets, 52 kinds of blended extract pellets were designed to test their palatability. The results showed that the pellets presented remarkably different palatability, and the optimal one was diet 52(wheat gluten meal: pet-food grade poultry by-product meal: meat and bone meal: corn gluten meal = 1:6:1:2). The highest ingestion ratio(the number of pellets ingested/the number of pellets fed) was 0.73 ± 0.03, which was observed in Diet 52. Then five isonitrogenous(52% crude protein) and isocaloric(20 k J g^(-1) gross energy) diets were formulated by replacing 0(control), 35%, 50%, 65% and 80% of fishmeal with No.52 blending proportion. After a 10-weeks feeding trial, a consistent feed intake was found among all replacement treatments. Replacement level of fishmeal up to 35% did not significantly influence final body weight, specific growth rate, feed efficiency ratio, and protein efficiency ratio of turbot. Therefore, the water-soluble extracts of protein sources play an important role in improving the palatability of non-fishmeal protein sources in aquafeed.

Favorable and unfavorable amino acid residues in water-soluble and transmembrane proteins

We analyzed the amino acid residues present in the water-soluble and transmembrane proteins of 6 thermophilic and 6 mesophilic species of the domains Archaea and Eubacteria, and characterized them as favorable or unfavorable. The characterization was performed by comparing the observed number of each amino acid residue to the expected number calculated from the percentage of nucleotides present in each gene. Amino acids that were more or less abundant than expected were considered as favorable or unfavorable, respectively. Comparisons of amino acid compositions indicated that the water-soluble proteins were rich in charged residues such as Glu, Asp, Lys, and His, whereas hydrophobic residues such as Trp, Phe, and Leu were abundant in transmembrane proteins. Interestingly, our results found that although the Trp residue was abundant in transmembrane proteins, it was not defined as favorable by our calculations, indicating that increased numbers of a particular amino acid does not necessary indicate it is a favorable residue. Amino acids with high G + C content such as Ala, Gly, and Pro were frequently observed as favorable in species with low G + C content. Comparatively, amino acids with low G + C content such as Phe, Tyr, Lys, Ile, and Met were frequently observed as favorable in species with high G + C content. These are the examples to increase the supply of amino acids than expected. Amino acids with neutral G + C content, i.e., Glu and Asp were favorable in water-soluble proteins from all species analyzed, and Cys was unfavorable both in water-soluble and transmembrane proteins. These results indicate that amino acid compositions are essentially determined by the nucleotide sequence of the genes, and the amino acid content is altered by a deviation from expectation.

Change of Water-Soluble-Protein, Urea-Soluble-Protein and Membrane Intrinsic Protein in Human Senile Cataract

Purpose:To analyze the change of water-soluble-protein(WSP),urea-soluble-protein(USP)and membrane intrinsic protein(MIP)in human senile catarct.Methods:The water-soluble-fractions(WSF)were prepared basically according to the method of Kibbelear,et al.But in this study,5mmol/LB-mercaptoethanol was added to the buffer solution.The urea-soluble-fractions(USF)were pre-pared basically according to the method of Kibbelear,et al.Lens fiber cell mem-branes were purified basically according to the method of Russell,et al.SDS-PAGE were performed according to the procedure of Laemmili,et al.using re-solving gel13%and3%stacking gel.Results:The WSPwas fractionated intoHM^+α^-,β1-3^-andγ-crystallin compo-nents.In nuclear cataractous lenses HM^+α^-and B-crystallin increase,while r-crystallin decrease.The USP from clear lenses contains mainlyαβchains of22KD,whereas in cataractous lenses,especially in nuclear cataractous lenses,the relative amount of the 28-and23KDpolypeptide(the components of β-crys-tallin)increased markedly.Lens fiber cell MIP,clear lens and cataract lens con-tained the main polypeptide of 27KD(MIP)and23KD(MP23).Conclusion:The water-insolube protein,whether in quantity or in quality,plays an important role in cataract formation.Eye Science 1995,11:124-127.

天然乳胶中过敏蛋白质的酶催化交联研究

天然乳胶中普遍存在引起人体过敏反应的水溶性蛋白质。用谷氨酰胺转氨酶催化天然乳胶中的蛋白质使其发生不同结构层次上的改变，致使水溶性蛋白质含量降低，在提高乳胶强度等性能的同时解决蛋白质过敏问题。通过响应面试验设计获得了MTGase催化天然乳胶蛋白交联的优化条件。

导数光谱法直接测定大豆水溶性蛋白中色氨酸和酪氨酸

根据色氨酸的四阶导数光谱在 2 92nm处有一特征吸收峰对蛋白质中色氨酸进行了定性定量 ,而利用色氨酸和酪氨酸在 2 83nm的四阶导数光谱吸收值减去色氨酸在 2 83nm的贡献可对酪氨酸进行定量。用四阶导数光谱法测定大豆水溶性蛋白中色氨酸和酪氨酸的含量 ,分别为 9.2± 0 .5mg/g和 2 7.4± 0 .7mg/g ,该法无破坏性、简单易行、快速、准确、灵敏度高 。

降低天然橡胶乳液中水溶性蛋白质含量的方法

介绍了天然乳胶引起过敏的原因,指出了过敏反应与胶乳中的水溶性蛋白质含量有关及蛋白质的种类。叙述了目前降低天然橡胶乳液中的水溶性蛋白质含量的研究现状及主要方法,它们分别为氯化处理、沥滤、多次离心法、置换法、酶处理法和辐射硫化法。而辐射硫化的方法最具有深化研究和全面推广价值。

State-of-the-art review on plant-based solutions for soil improvement

Vegetation has been used as a means in geotechnical engineering for soil improvement and erosion control.This paper aims to present a state-of-the-art review and future prospective on soil improvement and reinforcement with plants,mainly from a perspective of plant mechanical effects.The mechanics of roots and root-soil composite are reviewed with regard to experiments,including root mechanical tests,direct shear tests,pullout tests and triaxial tests.Various factors influencing root reinforcement are characterized and discussed to explain root-soil interactions and related soil strengthening mechanisms.Considering cost and efficiency,extreme climates,and the conflicting mechanisms of plant growth and soil improvement,researchers have introduced nature-based water-soluble polymers(WSPs)into soil improvement to promote vegetation establishment and provide additional binding strength between soil particles.Despite the benefits,existing related researches and concepts are scarce,and there is still a significant knowledge gap in the coupling effect of WSP and plants for soil improvement.The review indicates that the combination of vegetation and WSP has the potential to create“trade-off”and“complementarity”for progressive soil improvement.Finally,new research topics in the field of soil improvement with plants are identified in the review.

Effect of Long-term Experimental Warming on the Nutritional Quality of Alpine Meadows in the Northern Tibet

The nutritional quality of grasslands is closely related to recruitment of young and population dynamics of livestock and wild herbivores. However, the response of nutritional quality to climate warming has not been fully understood in the alpine meadow on the Tibetan Plateau, especially in the Northern Tibet. Here, we investigated the effect of experimental warming(beginning in 2008) on nutritional quality in three alpine meadows(site A: 4313 m, B: 4513 m and C: 4693 m) in the Northern Tibet. Crude protein(CP), neutral detergent fiber(NDF), acid detergent fiber(ADF), crude ash(Ash), ether extract(EE) and water-soluble carbohydrate(WSC) were examined in 2018–2019. Experimental warming only increased the content of CP by 27.25%, ADF by 89.93% and NDF by 41.20%, but it decreased the content of Ash by 57.76% in 2019 at site B. The contents of CP and WSC both increased with soil moisture(SM). The content of CP decreased with vapor pressure deficit(VPD). The combined effect of SM and VPD was greater than air temperature(Ta) in controlling the variations of the CP content, ADF content and nutritional quality. Compared to Ta, VPD explained more of the variation in NDF and Ash content. All of these findings suggest that warming effects on nutritional quality may vary with site and year, and water availability may have a stronger effect on the nutritional quality than temperature in the alpine meadow of the Northern Tibet.

Preliminary Analysis of Proteases Associated With Photosystem Ⅱ Particles

The photosynthetic apparatus of plant is localised in chloroplasts. During the photosynthesis, the absorption, transfer and conversion, of light energy, water-splitting reaction and photophosphorylation take place in the chlorophyll-protein complexes of geometrically arranged pigments and proteins embedded in thylakoid membranes. The turnover of thylakoid membrane proteins requires various proteolytic activities. The Dl reaction center protein (Q_B-binding protein) has been demonstrated to require