Enhanced Control of Bladder-Associated Tumors Using Shrimp Anti-Lipopolysaccharide Factor (SALF) Antimicrobial Peptide as a Cancer Vaccine Adjuvant in Mice

Shrimp anti-lipopolysaccharide factor (SALF) is an antimicrobial peptide with reported anticancer activities, such as suppression of tumor progression. In this study, we prepared a potential cancer vaccine comprised of SALF in conjunction with the cell lysate of inactivated murine bladder carcinoma cells (MBT-2), and evaluated its efficacy in a mouse tumor model. Our study shows that SALF added to cell culture media inhibits growth progression of MBT-2, and that SALF together with inactivated MBT-2 lysate elevates the level of inflammasome activity, and modulates the levels of IL-1β, MCP-1, IL-6, IL-12, and TNF-α in mouse macrophages. Immunization of 7, 14, and 21 day-old mice with the vaccine prevented growth of MBT-2 cell-mediated tumors. The vaccine was found to enhance expression of T-cell, cytotoxic T cells, and NK cells in the immunized mice groups. Recruitment of macrophages, T-helper cells, and NK cells was enhanced, but levels of VEGF were decreased in immunized mice. This report provides empirical evidence that our SALF as vaccine adjuvant enhances antitumor immunity in mice.     

Two Novel Antioxidant Nonapeptides from Protein Hydrolysate of Skate (Raja porosa) Muscle

In the current study, the preparation conditions of neutrase hydrolysate (SMH) from skate (Raja porosa) muscle protein were optimized using orthogonal L₉(3)⁴ tests, and R values indicated that pH was the most important factor affecting HO· scavenging activity of SMH. Under the optimum conditions of pH 7.0, enzymolysis temperature 60 °C, enzyme/substrate ratio (E/S) 2%, and enzymolysis time 5 h, EC₅₀ of SMH on HO· was 2.14 ± 0.17 mg/mL. Using ultrafiltration, gel filtration chromatography, and RP-HPLC, two novel antioxidant nonapeptides (SP-A and SP-B) were isolated from SMH and their amino acid sequences were found to be APPTAYAQS (SP-A) and NWDMEKIWD (SP-B) with calculated molecular masses of 904.98 Da and 1236.38 Da, respectively. Both showed strong antioxidant activities. SP-A and SP-B exhibited good scavenging activities on HO· (EC₅₀ 0.390 and 0.176 mg/mL), DPPH· (EC₅₀ 0.614 and 0.289 mg/mL), and O₂⁻· (EC₅₀ 0.215 and 0.132 mg/mL) in a dose-dependent manner. SP-B was also effective against lipid peroxidation in the model system. The aromatic (2Trp), acidic (2Asp and Glu), and basic (Lys) amino acid residues within the sequences of SP-B might account for its pronounced antioxidant activity. The results of this study suggested that protein hydrolysate and peptides from skate muscle might be effective as food additives for retarding lipid peroxidation occurring in foodstuffs.     

Isolation and Synthesis of Laxaphycin B-Type Peptides: A Case Study and Clues to Their Biosynthesis

The laxaphyci’s B family constitutes a group of five related cyclic lipopeptides isolated from diverse cyanobacteria from all around the world. This group shares a typical structure of 12 amino acids from the l and d series, some of them hydroxylated at the beta position, and all containing a rare beta-amino decanoic acid. Nevertheless, they can be differentiated due to slight variations in the composition of their amino acids, but the configuration of their alpha carbon remains conserved. Here, we provide the synthesis and characterization of new laxaphycin B-type peptides. In doing so we discuss how the synthesis of laxaphycin B and analogues was developed. We also isolate minor acyclic laxaphycins B, which are considered clues to their biosynthesis.     

不同蛋白质水平下添加小肽对石斑鱼生长、消化酶、血清生化和抗氧化能力的影响

设计6组实验,测定在3种不同饲料蛋白质水平(44%,48%,52%)下添加2种水平的小肽(0.05%,0.1%)对赤点石斑鱼(Epinephelus akaara)生长、消化酶、血清生化和抗氧化能力的影响。饲料分别为D1(44%,0.05%),D2(44%,0.1%),D3(48%,0.05%),D4(48%,0.1%),D5(52%,0.05%),D6(52%,0.1%)。每组饲料3个平行,每个玻璃钢纤维桶(500 L)放15尾石斑鱼[初始体质量(42.16±0.23)g],实验进行8周。结果显示,各组石斑鱼增重、特定生长率、肌肉粗蛋白、脂肪和灰分无显著差异,随着蛋白质和小肽水平的增加,肌肉粗脂肪、血清胆固醇和甘油三酯质量浓度降低(P0.05);胃蛋白酶活性在D2组最高,小肽对肠道淀粉酶、胰蛋白酶和脂肪酶活性不存在显著影响,在D1组活性较高(P0.05);各组石斑鱼肝脏丙二醛和过氧化物酶差异不显著(P0.05)。由上述结果可以看出在不同蛋白质水平下添加小肽可以降低石斑鱼的蛋白需求,促进脂肪代谢,增加消化酶活性。     

饲粮添加酶解蛋白肽对断奶仔猪生长性能、血清免疫指标和肠道菌群的影响

本试验旨在探究饲粮添加酶解蛋白肽对断奶仔猪生长性能、血清免疫指标和肠道菌群的影响,以确定断奶仔猪饲粮中酶解蛋白肽的适宜添加水平.试验选取150头21日龄体重为(7.01±0.17)kg的健康"杜×长×大"三元杂交断奶仔猪,随机分为5个组,每组5个重复,每个重复6头(公母各占1/2).各组断奶仔猪分别饲喂在基础饲粮中添加...     

Porcine Antimicrobial Peptide PR-39 Is Modulated by Lactoferrin in Marrow Cells

PR-39 is a porcine antimicrobial peptide that plays an important role in the innate defense mechanism. We produced monoclonal antibodies (MAbs) against PR-39 by fusing mouse myeloma cells with lymph node cells from BALB/c mice immunized with the reactive site sequence PR-11 of PR-39. Furthermore, we investigated the effect of lactoferrin on PR-39 gene levels and peptide concentrations in cultural supernatants of bone marrow granulocytes by RT-PCR and the competitive inhibition ELISA method established in this study. Two hybridomas 3H5 and 5H7 were selected for developing ascites and contained MAbs against PR-11, which were used for screening the specificity to PR-39 by competitive inhibition ELISA. We found that MAbs were successfully produced against PR-11 and the MAbs had a strong reaction with PR-39 excreted by porcine marrow granulocytes. The ascites had a relatively high titer and the purified MAbs were determined as IgG1. Incubation with 10 or 100 µg/mL lactoferrin significantly increased (P < 0.05) PR-39 mRNA levels in bone marrow granulocytes after 3 h and 6 h, but 1000 µg/mL lactoferrin reduced (P < 0.05) PR-39 mRNA expression after 3 h and 6 h compared with control (no lactoferrin added). The relative concentrations of PR-39 in supernatant secreted by marrow granulocytes were significantly increased by 1000 µg/mL lactoferrin after both 3 h and 6 h. These findings suggest a regulatory role of lactoferrin for the antimicrobial peptide PR-39 in marrow cells in vitro. It is possible that the regulation of antimicrobial peptide PR-39 expression may be one of the protective mechanisms of lactoferrin in pigs.     

抗菌肽的研究进展

抗菌肽是生物体在抵御病原微生物的防御反应中所产生的一类具有抗微生物与一些恶性细胞的短肽,一般具有抗菌作用。本文主要综述抗菌肽的分类和作用、性质和作用机制及其分离和提纯。     

苷肽注射液对猪免疫器官及血液指标的影响研究

通过对猪注射不同剂量的苷肽注射液,研究了苷肽注射液对猪的免疫器官和血液指标的影响。结果表明,苷肽注射液在一定程度上可促进猪体重增长,对猪免疫器官的影响不显著,对血液指标未见不良影响。合适剂量的苷肽注射液能够促进仔猪外周血淋巴细胞PHA的增殖。     

酶法制备驴骨多肽的工艺研究

[目的]研究酶法水解驴骨蛋白制备骨多肽的工艺,可为充分挖掘骨蛋白资源及开发骨蛋白深加工产品提供理论依据,具有重要的科学意义。[方法]以水解度和氮溶出率为考察指标,对驴骨进行高温高压蒸煮、不同食品级蛋白酶水解及酶解条件的研究。[结果]提取驴骨蛋白的最佳蒸煮条件为：温度121℃,压力0．1MPa,蒸煮时间4h;木瓜蛋白酶的水解产物具有较高的水解度和氮溶出率,为最佳水解酶;驴骨粉经121℃加热预处理30min可提高酶解效果;木瓜蛋白酶的最佳水解条件为：水解时间5h,底物浓度8％．pH值6．0,加酶量7000U／g,温度55℃;木瓜蛋白酶水解驴骨蛋白的酶解产物pH值在5～9时,氮溶解指数高于88％,三氯乙酸氮溶解指数达84％。[结论]该酶水解的产物具有较高的溶解性,大部分为低分子肽,可直接应用于食品中。     

文蛤蛋白抗菌肽制备工艺优化与抗菌活性研究

[目的]为文蛤的深加工提供科学依据。[方法]以鲜活文蛤为供斌材料,采用胰蛋白酶水解文蛤肉,选取大肠杆菌作为供试菌检测酶解物的抗菌活性,并采用响应面回归分析法优化酶解工艺。[结果]胰蛋白酶酶解文蛤蛋白的最优条件为：酶用量0．5％,酶解时间8h,酶解温度40℃;酶解液经蛋白质层析系统层析分离得到7个洗脱峰;抗菌性检测结果显示第2个洗脱峰的抗菌性最强,其分子质量为1650u。[结论]胰蛋白酶水解文蛤肉的酶解产物具有明显的抗菌性。