洋葱苯丙氨酸解氨酶基因AcPAL2的克隆与表达分析

利用简并PCR技术和RACE技术克隆得到了一条洋葱的苯丙氨酸解氨酶(PAL)基因全长cDNA序列。该cDNA序列全长2349 bp,编码长685个氨基酸残基的多肽序列,命名为AcPAL2。Blast分析表明该序列与虎眼万年青Galtonia saundersiae、野蕉Musa balbisiana的相似性均较高。Real-time PCR表达及花青素含量分析表明,红皮洋葱该基因表达量最大,而黄皮和白皮洋葱表达量极低;在红皮洋葱中该基因在膨大初期大量表达,并迅速降低至一定程度后趋于相对平稳表达,且与花青素的积累过程相一致。     

Virion glycosylation governs integrity and infectivity of infectious pancreatic necrosis virus

The possible importance of the O-linked glycosylation in virion stability and infectivity of infectious pancreatic necrosis virus (IPNV) was analysed. Enzymatic treatment with O-glycosidase of radiolabelled virions under different ionic conditions, to allow for possible alternative exposure of glycosidic enzyme cleavage sites, did not alter the specific infectivity of virions re-isolated after rate-zonal centrifugation in glycerol gradients. As an alternative method to assess the significance of carbohydrates in IPNV integrity, periodate oxidation in the presence of an aldehyde quencher was chosen. Following re-isolation of viruses, a 3-5 (10)log-unit reduction in specific infectivity was revealed and, at higher concentrations, a total disruption or virion aggregation was observed. The loss of infectivity of intact virions was not because of a lack of attachment to cells. Additionally, re-evaluation of reading values from UV-spectra of purified IPNV yielded a specific infectivity of 3 × 10(11) TCID(50)-units mg(-1) of protein and a ratio of 40 virions per TCID(50)-unit in the CHSE-214 cell system.     

Bioproduction of Chitooligosaccharides: Present and Perspectives

Chitin and chitosan oligosaccharides (COS) have been traditionally obtained by chemical digestion with strong acids. In light of the difficulties associated with these traditional production processes, environmentally compatible and reproducible production alternatives are desirable. Unlike chemical digestion, biodegradation of chitin and chitosan by enzymes or microorganisms does not require the use of toxic chemicals or excessive amounts of wastewater. Enzyme preparations with chitinase, chitosanase, and lysozymeare primarily used to hydrolyze chitin and chitosan. Commercial preparations of cellulase, protease, lipase, and pepsin provide another opportunity for oligosaccharide production. In addition to their hydrolytic activities, the transglycosylation activity of chitinolytic enzymes might be exploited for the synthesis of desired chitin oligomers and their derivatives. Chitin deacetylase is also potentially useful for the preparation of oligosaccharides. Recently, direct production of oligosaccharides from chitin and crab shells by a combination of mechanochemical grinding and enzymatic hydrolysis has been reported. Together with these, other emerging technologies such as direct degradation of chitin from crustacean shells and microbial cell walls, enzymatic synthesis of COS from small building blocks, and protein engineering technology for chitin-related enzymes have been discussed as the most significant challenge for industrial application.     

Glycoproteomic profiling of serum peptides in canine lymphoma and transitional cell carcinoma

Differential expression of fucosylated glycoproteins has been correlated with malignancy and metastatic potential in various types of neoplasia. Utilizing glycoproteomics techniques, changes in fucosylated serum peptides associated with naturally occurring canine lymphoma and transitional cell carcinoma (TCC) have been evaluated. In both types of neoplasia, the majority of the fucosylated peptides that changed increased with the cancer. In one lymphoma case that was examined over the course of the disease, the same fucosylated peptides that increased during pre-chemotherapy decreased during post-chemotherapy, and then subsequently increased upon recurrence of the lymphoma. When comparing all the fucosylated peptides that increased in both types of cancer, there were only two peptides in common allowing discrimination between lymphoma and TCC based on their peptide profiles. These results emphasize the prospect of glycopeptide profiling in proteomics for use in discovering a panel of non-invasive, diagnostic or prognostic biomarkers of cancer.     

乳清蛋白-低聚异麦芽糖的制备及抗原性研究

将低聚异麦芽糖通过糖基化引入乳清蛋白制备乳清蛋白-低聚异麦芽糖,用间接竞争ELISA法测定不同乳清蛋白与低聚异麦芽糖质量比,不同反应时间生成的乳清蛋白-低聚异麦芽糖中α-乳白蛋白和β-乳球蛋白抗原性的变化。结果表明:糖基化能有效降低乳清蛋白中α-乳白蛋白和β-乳球蛋白的抗原性;不同反应时间、不同乳清蛋白与低聚异麦芽糖质量比对乳清蛋白中α-乳白蛋白和β-乳球蛋白抗原性的影响不同,乳清蛋白与低聚异麦芽糖的质量比为1∶4,反应24 h时效果最好,α-乳白蛋白的抗原性从25.67μg/mL降低到9.33μg/mL,β-乳球蛋白的抗原性从97.82μg/mL降低到28.25μg/mL。     

糖基化鸡蛋清大豆复合蛋白饮料加工技术研究

研究糖基化鸡蛋清大豆复合蛋白饮料的加工工艺,通过单因素及正交试验,确定了最佳配方及工艺条件。试验结果表明,选择合适的复合乳化稳定剂和采用预乳化及二次高压均质工艺,均有助于提高复合蛋白饮料的稳定性。     

葡萄中糖基化花色苷研究进展

葡萄果实与葡萄酒的颜色由其所含花色苷的种类和含量决定,而花色苷是由花色素经过糖基化修饰转变而成,所以糖基化修饰在葡萄果实花色苷合成途径中起着重要作用。葡萄果实中的糖基化花色苷主要包括花色素的3–O–葡萄糖基和3,5–O–双葡萄糖基,即花色素单糖苷和花色素双糖苷,糖基化花色苷的组成是决定红葡萄酒品质的关键因素之一。对糖基化花色苷在葡萄果实中的组成及其对葡萄酒颜色和稳定性的影响进行了简要介绍,重点对花色素单糖苷和花色素双糖苷合成的关键酶基因以及转录因子进行了综述,以期为葡萄果实糖基化花色苷合成的调控机理的全面揭示和优质红色酿酒葡萄品种的选育提供信息。     

空化射流条件下大豆分离蛋白糖基化产物乳液特性研究

为探究空化射流对大豆分离蛋白糖基化产物乳液特性的影响,以大豆分离蛋白、葡萄糖、葡聚糖为原料,通过空化射流处理辅助糖基化制备大豆分离蛋白-葡萄糖共价复合物乳液、大豆分离蛋白-葡聚糖共价复合物乳液,探究空化射流技术对大豆分离蛋白糖基化产物乳液的粒径、ζ-电位、微观结构、蛋白吸附率、乳析指数及抗氧化性的影响。结果表明：经过一定时间的空化射流处理后的糖基化产物乳液平均粒径显著降低、ζ-电位增大、微观结构液滴逐渐变得均匀,蛋白吸附率升高、乳析指数降低、还原力和DPPH自由基清除能力均升高,并在空化射流处理80 min时,乳液特性达到最佳,且相比大豆分离蛋白-葡萄糖共价复合物乳液,大豆分离蛋白-葡聚糖共价复合物呈现出更好的乳液特性;但随着空化射流处理时间的进一步增加,糖基化产物乳液的平均粒径升高、ζ-电位减小、微观结构开始出现聚集情况,蛋白吸附率呈降低趋势,乳析指数逐渐升高。适当时间下的空化射流辅助处理可以改善糖基化产物的乳液特性,提高乳液的储藏特性和抗氧化特性。     

Advanced glycosylation end products promote migration of podocytes through mTORC1/uPAR pathway

AIM: To investigate the influence of advanced glycosylation end products-modified bovine serum albumin (AGE-BSA) on mammalian target of rapamycin complex 1 (mTORC1), urokinase-type plasminogen activator receptor (uPAR), and cell mobility in the podocytes, and to further explore the probable relationship. METHODS: The conditionally immortalized mouse podocyte cell line was cultured in vitro. MTT assay and immunofluorescence were used to analyze the cell viability and cytoskeleton of the podocytes treated with the stimuli and intervention agents. The activity of mTORC1 and the expression level of uPAR in normal podocytes and podocytes treated with control BSA or AGE-BSA were detected by Western blotting. The migration ability of the podocytes was determined by would-healing assay. Rapamycin was added to inhibit the activity of mTORC1 along with the addition of AGE-BSA to observe the changes of uPAR and the motility of podocytes. RESULTS: No significant difference of the cell viability or cytoskeleton in the podocytes treated with the stimuli and intervention agents was observed. AGE-BSA up-regulated the activity of mTORC1 and the expression of uPAR, and induced the high mobility of the podocytes. Rapamycin obviously reduced the high expression level of uPAR and the increase in the migration ability of podocytes caused by AGE-BSA treatment. CONCLUSION: AGE-BSA might cause the high migration of podocytes through the mTORC1/uPAR signaling pathway.     

The involvement of N‐glycosylation of zona glycoproteins during meiotic maturation in sperm–zona pellucida interactions of porcine denuded oocytes

The present study was conducted to delineate whether N‐glycosylation of zona pellucida (ZP) glycoproteins occurred during meiotic maturation and whether this N‐glycosylation played a role in sperm–ZP interactions of porcine cumulus denuded oocytes (DOs). After mechanical removal of cumulus cells from cumulus oocyte complexes (COCs), DOs were cultured for 44 h in in vitro maturation (IVM) culture. The experiments were carried out to determine the effects of tunicamycin, a specific N‐glycosylation inhibitor, for various intervals during IVM on sperm–ZP interactions in porcine DOs. The results determined that DOs could induce meiotic maturation, although the maturation rate of DOs was earlier than that of COCs. In addition, N‐glycosylation of ZP glycoproteins occurred during meiotic maturation and was crucial in sperm–ZP interactions, was responsible for sperm penetration, sperm binding to ZP and induction of acrosome reaction in ZP‐bound sperm. However, the inhibition of N‐glycosylation by tunicamycin during IVM did not influence ZP hardness and male pronuclear formation, indicating that this N‐glycosylation was involved in the initial stage of fertilization. We conclude that 24–44 h of N‐glycosylation of ZP glycoproteins during meiotic maturation was crucial in sperm penetration and sperm binding to ZP and the induction of acrosome reaction in sperm bound to ZP of porcine DOs.