Cranberry derived proanthocyanidins can prevent pathogen invasion of kidney epithelial cells

The in vitro effectivity of cranberry derived proanthocyanidins (PACs) for the mitigation of kidney cell infection by selected uro- and entero-pathogens is examined with an adhesion/invasion assay and confocal microscopy. This study demonstrates that PACs effectively reduce invasion of canine kidney cells by pathogenic bacteria: Escherichia coli CFT073 and O157:H7, Enterococcus faecalis 29212, and Pseudomonas aeruginosa 10145. These effects demonstrate the potential for cranberry derived PACs as a useful tool in the prevention of kidney infection.     

克诺罗杆菌检测用单克隆抗体的制备及功效评价

目的:选择克诺罗杆菌标准菌株中的多株代表菌株作为抗原,采用多抗原组合免疫的方法,筛选制备抗克诺罗杆菌属（Cronobacter spp.）检测用单克隆抗体（monoclonal antibody,mAb）,并对获得的抗体进行各项指标评价,为进一步建立克诺罗杆菌免疫学快速检测方法创造条件。方法:采用冻融裂解、超声破碎、全颗粒三种方法制备抗原,以克诺罗杆菌标准菌株及分离菌株20株,9株非克诺罗杆菌进行筛选。筛选获得的抗体鉴定特异性,进行Ig亚类分型,测定效价及相对亲和力常数。结果:获得6株针对克诺罗杆菌的杂交瘤细胞株,腹水效价均在1∶107以上;相对亲和常数均大于1.0×1010L/mol。采用\     

米胚芽中胰脂肪酶抑制剂的分离纯化

由米胚芽中提取的胰脂肪酶抑制剂经鉴定主要为蛋白质.通过硫酸铵分级沉淀(40%～80%)、凝胶层析(Sephadex G-75)对米胚芽水溶物进行分离纯化.所得的洗脱峰I和洗脱峰Ⅱ的组分进行高效液相色谱分析,测定了胰脂肪酶活性抑制率较高的组分的分子量,分别为125KD和21KD.     

Cabernet Sauvignon wines from two different clones, characterization and evolution during bottle ageing

Phenolic compounds constitute important quality parameters of wines. Wines produced from different clones of the same grape variety show differences in relation to their chemical composition. The aim of this study was to characterize and differentiate Cabernet Sauvignon wines from two clones in relation to their chemical composition and to examine changes in the phenolic composition and antioxidant activity during wine ageing in the bottle. All wines were produced with Cabernet Sauvignon grapes, clones 685 and 169, from two vineyards, under the same microvinification conditions. The wines were characterized in relation to phenolic composition and antioxidant activity, as well as monitored over 11 months of bottle ageing. A significant difference was observed between the chemical compositions of the wines produced from clones 169 and 685, clone 169 showing the highest phenolic content while clone 685 had better color characteristics. The wines showed high antioxidant activity. Principal components and cluster analyses demonstrated separation of the wine according to the clone. In relation to wine bottle ageing, for both clones evaluated was observed a decrease in all phenolic compound, except of quercetin, and the antioxidant activity of these wines increased during storage.     

Isolation and characterization of melanic pigments derived from tea and tea polyphenols

The dark brown pigments derived from tea and tea polyphenols were studied. Physical and chemical properties revealed that pigments directly extracted from tea leaves and derived from tea polyphenols were similar to typical melanins. Further investigation showed that both melanic pigments possessed similar antioxidant capability, due to their chelating and scavenging properties. The inhibitory effect of melanic pigments, either from tea or tea polyphenols, was significantly stronger than that of non-treated tea polyphenols. According to these properties, we have extracted melanin from tea. In addition, oxidation of tea polyphenols also provided an alternative method to maximize the yields. The extracted melanin is an antioxidant, which interrupted free radical reactions at a step in the development chain by its scavenging properties and, at the step of initiation, by its ability to chelate metals.     

Purification and characterization of antioxidative peptides derived from rice bran protein hydrolysates

Rice bran protein fraction (RBPF)—albumin, globulin, glutelin and prolamin were hydrolyzed with proteases M, N, P, S and pepsin under their optimal conditions for 24 h. Hydrolysates of various hydrolysis periods were collected and subjected to peptide mapping and the antioxidative activity measured by the 2,2-Azino-bis-3-ethylbenzothiazoline-6-sulfonic Acid (ABTS) method. Protease M hydrolysates showed high degree of hydrolysis (DH), but low antioxidative activity. On the contrary, pepsin hydrolysates showed low DH with high activity. Albumin and globulin hydrolysates had higher DH values, but lower values for glutelin and prolamin. The globulin hydrolysate (Opep2) from 2 h-pepsin hydrolysis was separated by using three consecutive purification steps with RP-HPLC. Nineteen antioxidative peptides were isolated and their amino acid sequences were determined by a gas-phase protein sequencer and MALDI-TOF mass spectrometry. These peptides were composed of 6–30 amino acid residues with molecular masses ranging from 670–3,611 Da. Tyr-Leu-Ala-Gly-Met-Asn had the highest antioxidative activity among them.     

Production and physicochemical characterization of resistant starch type III derived from pea starch

Smooth pea starch was used for the production of physiological important resistant starch type III. For reduction of the molecular weight of the starch, different strategies including enzymatic debranching and acid hydrolysis (lintnerization), were tested to obtain an optimal starting material for retrogradation. The resulting polymer chain lengths were analyzed by high-performance anion-exchange chromatography. Temperature regimes and starch concentrations in gel were optimized during the retrogradation with the aim to obtain a high yield of resistant starch. Optimal conditions led to resistant starch contents up to 74%. The products were thermostable and showed no loss of resistant structures after autoclaving. The peak temperatures of the thermal transition were at approximately 147 degrees C. The resulting resistant starch products are suitable for the generation of functional foods.     

肉制品中牛源性成分Taqman荧光定量PCR检测法的建立

本实验根据牛线粒体差异序列设计特异性PCR引物和Taqman探针,并基于16S rDNA内参基因设计通用引物及Taqman探针,绘制并通过标准曲线确定样品中总DNA浓度以及牛源性成分DNA浓度,采用相对定量法测定肉制品中牛源性成分的质量分数。并通过特异性、灵敏度实验,及混合肉样回收率及市售肉制品检测,对本方法进行验证。结果表明,方法特异性强,可对牛肉DNA进行特异性扩增。最低检出限为10 pg/μL,具有较高的灵敏度。并根据回收实验可知,平均回收率为98.62%。可以为肉制品中牛肉含量的测定提供技术参考。     

Purification and characterization of rat alpha-lactalbumins: apparent genetic variants

Rat alpha-lactalbumin, from the milk of Fischer 344 (CDF) rats, was isolated and purified by a combination of gel filtration and diethylaminoethyl-cellulose ion exchange chromatography. Three electrophoretically distinct proteins had alpha-lactalbumin activity. Staining for carbohydrate indicated that at least two of the three forms were glycoproteins. The low molecular weight protein fraction from the wheys of two additional strains of laboratory rat were compared to ascertain whether the composition of this fraction was common in the divergent strains. Outbred Wistar and Long-Evans dams yielded wheys containing up to six forms of alpha-lactalbumin. Either one or both of two groups of three alpha-lactalbumins were in a given milk sample. The two groups of three alpha-lactalbumins appear to represent two genetic variants upon which is imposed a polymorphic character. All forms of alpha-lactalbumin, within and between strains, were immunologically identical.     

石屏臭豆腐来源的高产蛋白酶菌株筛选及酶学特性研究

目的:通过石屏臭豆腐产蛋白酶优势菌株发酵获得高产蛋白酶菌种资源。方法:采用单因素和响应面试验对培养基及发酵条件进行优化;以酪蛋白为底物,利用酶学技术探究了温度、pH、金属离子、有机化学试剂对JX-11菌株蛋白酶活性和稳定性的影响。结果:从石屏臭豆腐中分离1株高产蛋白酶的优势菌JX-11,经鉴定为彭尼普尔金黄杆菌(Chryseobacterium pennipullorum)。JX-11菌株最优产酶条件为温度23.0℃、葡萄糖添加量6.7 g/L、蛋白胨添加量15.0 g/L、pH 6.4,该条件下所产蛋白酶酶活力为(39.16±3.24) U/mL。JX-11菌株产蛋白酶的最适温度为30℃,在10～40℃范围内具有良好的稳定性;最适pH为7.0,在pH 6.0～9.0范围内具有良好的稳定性;Mn²⁺可显著提高JX-11蛋白酶的活性,相对空白组酶活力提升了4.33倍;Zn²⁺、Cu²⁺、K⁺均抑制该酶活性,Na⁺、Mg²⁺、Ca²⁺无显...     

Recombinant expression and characterization of N-acetylglucosaminyltransferase I derived from Nicotiana tabacum

The C-terminal catalytic domain of tobacco N-acetylglucosaminyltransferase I fused to maltose-binding protein was produced in Escherichia coli as a soluble form with significant activity. The protein was affinity-purified using amylose resin, and its enzymatic properties were investigated, including its divalent cation requirements, optimal temperature, optimal pH, and substrate specificity.     

Purification and characterization of antioxidative peptide derived from muscle of conger eel (Conger myriaster)

The tryptic hydrolysate of conger eel (Conger myriaster) muscle protein was fractionated according to the molecular weights using ultrafiltration (UF) membrane system. The lowest molecular weight fraction (<1 kDa) with higher antioxidative properties was purified using consecutive chromatographic techniques and designated conger eel antioxidative peptide (CEAP). Sequence determination revealed that it contained nine amino acids in its sequence (LGLNGDDVN) and the molecular mass was identified to be 928 Da. CEAP performed better than the natural antioxidant, α-tocopherol for the prevention of lipid peroxidation in vitro. Additionally, it scavenged hydroxyl radicals and carbon-centered radicals at IC₅₀ values of 74.1 μM and 78.5 μM, respectively. Therefore these results suggested that the peptides derived from conger eel protein hydrolysates are responsible for higher antioxidative properties and molecular weight as well as presence of hydrophobic amino acids highly contributed for their antioxidation.     

Growth and adhesion of osteoblast-like cells derived from neonatal rat calvaria on calcium phosphate ceramics

The effects of biocompatible ceramics on the growth and adhesion of osteoblast-rich rat calvarial cell cultures were investigated. Osteoblast-like cells and mouse fibroblast-like L-929 cells were cultured on composite sinters of hydroxyapatite (HAP) and beta-tricalcium phosphate (TCP) culture carriers, whose Ca/P molar ratios were adjusted to values of 1.50, 1.55, 1.60, 1.64 and 1.67. The growth rates of both cell types were accelerated on the TCP-HAP ceramics as compared to those on polystyrene plastic (LUX) or bioinert zirconia ceramics. The population of osteoblast-like cells reached a density of 2.28 x 10(5) cells/cm2 on 100% HAP (Ca/P ratio 1.67) at 9 d of culture, while the corresponding cell density was 1.66 x 10(5) cells/cm2 on LUX and 1.26 x 10(5) cells/cm2 on zirconia. Adhesion of the osteoblast-like cells on TCP-HAP ceramics was similarly increased as compared with that on LUX or zirconia ceramics. The adhesion of L-929 cells on TCP-HAP ceramics was found to be weaker than that on cultures on LUX or zirconia ceramics. The time-dependent variations in the alkaline phosphatase activity of the osteoblast-like cells showed that the osteoblastic phenotype was potentiated by culturing the cells in calcium-rich media. The surface analyses of the Ca/P ratio and the microstructure by XRD and FTIR suggest that the Ca-rich surface was newly formed by recombination on the surface layer in the culture medium containing fetal bovine serum. These results suggest that the surface of TCP-HAP ceramics, especially that of 100% HAP ceramics, are effective for accelerating growth and differentiation of osteoblast-like cells. This is most probably due to the chemical and physical instability and composition of 100% HAP, which promote the formation of a Ca-rich layer at the cell-material interface and provision of Ca ions to the osteoblast-like cells.     

Epigenetic toxicity of hydroxylated biphenyls and hydroxylated polychlorinated biphenyls on normal rat liver epithelial cells

2-Biphenylol, 3-biphenylol, 2,2'-biphenyldiol, 3,3'-biphenyldiol, 3-chloro-2-biphenylol, and 4,4'-dichloro-3-biphenylol were evaluated using the scrape-loading/dye transfer (SL/ DT) technique to determine in vitro gap junctional intercellular communication (GJIC) in a normal rat liver epithelial cell line as a measure of the epigenetic toxicity. Cytotoxicity was determined using the neutral red uptake assay. A dose range of 0-300 microM was examined. Only 3,3'-biphenyldiol and 4,4'-dichloro-3-biphenylol induced cytotoxicity within the tested dose ranges. Noncytotoxic doses were selected for evaluation of epigenetic toxicity. 4,4'-Dichloro-3-biphenylol was most inhibitory to GJIC at the lowest dose. The cytotoxicity and GJIC inhibitory effects observed for 4,4'-dichloro-3-biphenylol might be, although not exclusively, a consequence of the lipophilic nature of this chemical. 3-Chloro-2-biphenylol was least inhibitory to GJIC. 3-Chloro-2-biphenylol was less inhibitory to GJIC than 2-biphenylol because of the presence of the chlorine functional group, which appears to attenuate the toxic effect of the ortho-hydroxyl group. Although cells were capable of complete recovery of GJIC after removal of each of the chemicals, only with 2,2'-biphenyldiol and 4,4,'-dichloro-3-biphenylol did the cells demonstrate partial recovery without removal of the chemical. The more noncoplanar conformation of 2,2'-biphenyldiol and 2-biphenylol might explain their more inhibitory behavior in comparison to 3,3'-biphenyldiol and 3-biphenylol, respectively.     

Manufacture and characterization of gelatin films derived from beef,pork and fish sources using twin screw extrusion

Gelatin films derived from beef, pork and fish sources were manufactured by twin-screw, co-rotating extrusion. The effect of extrusion processing parameters, namely; screw speed (100–400 rpm) and temperature (90, 90, 90, 90 °C and 90, 120, 90, 90 °C) on the mechanical and barrier properties of gelatin films were studied. Increasing screw speed up to 300 rpm improved (P < 0.05) tensile strength (TS) and reduced (non-significantly) water vapour permeability (WVP) values for all manufactured gelatin films. However, the WVP of various gelatin film types was reduced (P < 0.05) when a screw speed of 400 rpm was employed. Increasing the speed of extrusion promoted (P < 0.05) increased solubility of films in water. Manufacture of films using a higher temperature profile resulted in films possessing higher puncture strengths (PS), increased water barrier properties with higher water solubility.