双斑东方鲀鱼皮胶原多肽的制备及其在化妆品中的功效与刺激性评价

河豚鱼皮中富含胶原蛋白,是一种优质的胶原多肽制备原料。鱼皮的精深加工不仅能减缓资源的浪费也能扩大我国河豚鱼的加工模式。本研究以双斑东方鲀鱼皮为实验对象,通过单因素实验和正交实验制备得到双斑东方鲀鱼皮多肽(Fugu bimaculatus collagen peptide,FBCP)并对其功效性及皮肤刺激性进行了研究。结果显示,碱性蛋白酶制备FBCP的最佳工艺条件为固液比1∶10、酶解温度50℃、加酶量8 000 U/g、酶解pH值9.0、酶解时间4 h。在此条件下,FBCP的肽得率为39.65%。利用超滤膜将胶原多肽提取液分离成不同分子量的四种组分,分别为FBCP1(Mw1 kDa)、FBCP2(1 kDaMw5 kDa)、FBCP3(5 kDaMw10 kDa)和FBCP4(Mw10 kDa)。吸湿保湿试验中,FBCP1组分显示出优于其它组分的吸湿和保湿性能。体外抗氧化实验结果表明,FBCP1自由基清除活性最好,其对超氧阴离子O■、羟基自由基·OH和DPPH的IC_(50)分别为1.659、5.582和1.801 mg/mL。多次皮肤刺激和急性眼刺激实验表明,涂抹高达50%(W/V)FBCP对受试兔皮肤及兔眼均无刺激性。综上所述,FBCP具有良好的抗氧化和保湿功效且对皮肤和眼睛无刺激性,可为其在化妆品中的应用提供基础参考。     

若羌红枣多糖提取方法的研究

目的:比较研究几种提取若羌红枣多糖的方法.方法:通过正交实验设计研究影响若羌红枣多糖提取的诸因素如提取料液比、温度、提取时间、提取次数等,确定条件范围,优化提取条件,得到提取若羌红枣多糖的最佳工艺条件.结果:热水法提取红枣糖的最佳条件:提取温度100℃、料液比1:16、提取时间4h,提取1次;酶法提取红枣多糖提取的最佳条件:pH4.5,温度60℃、时间1h,酶用世0.03%;碱法提取红枣多糖的对佳条件:Na2 CO3,温度80℃、时间3h,料液比1:20.结论:三种提取方法以酶提取法的效率最高,碱提取法次之,热水提取法的效率最低.     

海马总蛋白提取及其酶解条件优化

为了提取海马总蛋白并确定最佳的酶解条件,将海马粉碎后采用水提法提取海马总蛋白。分别选用木瓜蛋白酶、碱性蛋白酶、中性蛋白酶和胰蛋白酶,在不同酶解p H、时间、温度和E/S条件下进行单因素和正交试验法对海马总蛋白的酶解条件进行优化。利用聚丙烯酰胺凝胶电泳和BCA法来分别检测不同条件下的酶解情况及其蛋白含量,根据蛋白水解度来确定其最佳的酶解条件。实验结果表明:从10 g干海马中提取总蛋白为1.056 g,蛋白浓度为0.106 g/m L。海马总蛋白的最佳水解酶为碱性蛋白酶,其最佳酶解条件为:p H 9,E/S为5%,温度为50℃,时间为3 h,获得海马总蛋白的最大水解度为96.9%。研究获得了海马总蛋白及其最佳酶解条件,并为海马多肽生物活性研究奠定了基础。     

水解乳蛋白的制备及在细胞培养中的初步应用

采用正交法优化复合酶(胰酶和中性蛋白酶)水解凝乳酶干酪素制备水解乳蛋白(lacto-protein hydrolysate,LPH)的制备工艺,通过BHK和Vero细胞的培养效果检测水解乳蛋白的促细胞生长作用。结果显示水解乳蛋白的最佳制备工艺为:胰酶∶中性蛋白酶=2∶1(质量比),40℃,pH 7.0,酶/底物(E/S)=1∶5(质量比)水解6 h。所得产物氨基氮含量3.21 g/L,多肽含量35.63 g/L,游离氨基酸含量14.17 mg/mL,收率达40.20%。BHK和Vero细胞培养24 h,细胞密度均为各自空白的2.0倍,分别为Hyclone产品的1.0倍和0.86倍;培养48h,分别为各自空白的5.0倍和4.0倍,均为Hyclone产品的0.88倍。因此,该工艺简单,耗时短,制备得水解乳蛋白对BHK和Vero细胞生长有明显的促进作用。     

金针菇多糖的提取工艺优化及荧光标记研究

通过响应面法优化金针菇多糖热水浸提的最佳工艺,并用异硫氰酸荧光素(FITC)标记金针菇多糖(FVP),研究标记多糖的体外稳定性和细胞毒性。结果表明:优化的最佳浸提条件为液料比41∶1(m L∶g)、提取温度92℃、提取时间3 h,金针菇多糖的提取率为4.87%;通过还原胺化反应实现了金针菇多糖的FITC标记,FITC的取代度为0.90%,在24 h内标记的金针菇多糖体外稳定性良好,且不影响FVP的抑瘤活性。     

正交实验法优化薄荷中迷迭香酸提取工艺研究

目的用正交试验法对薄荷中迷迭香酸的含量进行检验,优化薄荷的提取工艺。方法以浸膏得率及薄荷中迷迭香酸含量为考察指标,考察料液比(A)、提取时间(B)、提取次数(D)3个影响因素,采用L9(34)正交试验筛选最佳水提工艺,考察浸膏得率,并运用高效液相色谱法(HPLC)测定迷迭香酸含量并定性定量分析。结果最佳提取工艺为料液比1∶18,浸提3次,每次1h。结论优选的提取工艺方法简单、稳定可行。     

花椒籽黑色素提取和脱蛋白技术研究

采用二次回归正交旋转组合试验优化了花椒籽黑色素的浸提工艺,并用蛋白酶酶解-Sevag法联用脱除花椒籽黑色素中的蛋白.结果表明:影响花椒籽黑色素提取效果的因素依次为温度>NaOH浓度>料液比,花椒籽黑色素提取的优化工艺参数为NaOH浓度为1.20 mol/L,料液比为1∶24.64,温度为70℃下提取2 h,共2次,所得花椒籽色素粗品为棕黑色无定型粉末,得率为6.1%,色价为201.62,蛋白质含量为44.83%~48.63%.碱性蛋白酶脱蛋白条件为温度50℃,pH 9,加酶量为粗色素溶液(浓度为1 mg/mL)体积的6%,再用Sevag法处理3次,蛋白质脱除率可达81.23%,花椒籽黑色素色价可提高1.5倍.     

蚯蚓外源酶与内源酶酶解产物分析

本试验采用了枯草杆菌(Bacillus subtilis)AS1.398枯草杆菌蛋白酶和自溶制备蚯蚓肽,通过前期单因素试验,设计正交试验L9(34),以氨基氮数,多肽浓度为衡量指标,对最佳酶解条件进行筛选研究,并分析了酶解液氨基酸组成和相对分子量的分布。结果表明:AS1.398枯草杆菌蛋白酶最佳酶解条为pH 6.5、酶浓度1%、温度50℃、反应时间8 h,在此条件下,酶解蚯蚓蛋白的每100 mL水解液氨基氮数可以达到16.55 mmol,多肽浓度达9.22 mg/mL;自溶酶解蚯蚓的最佳条件pH 7.0、底物浓度1∶2、温度50℃、反应时间6 h,在此条件下,酶解蚯蚓蛋白的每100 mL水解液氨基氮数可以达到21.55 mmol,多肽浓度达11.65 mg/mL;二者酶解产物分子量大部分是在5000以下的多肽、小肽及氨基酸的混合物,其中分子量在300以下占了80%,氨基酸组成平衡,含量丰富,可用来制取新型氨基酸微量元素及小肽添加剂。通过控制酶解条件,蚯蚓可以利用自身的酶源自溶来代替外源酶,从而降低成本。     

水蒸气蒸馏法提取大蒜挥发油的工艺研究

以挥发油提取率为指标,通过单因素和L9(34)正交试验设计确定了水蒸气蒸馏法提取大蒜挥发油的最佳提取工艺及条件。结果表明,各因素作用主次顺序为蒸馏时间(D)>料液比(C)>发酵温度(A)>浸泡时间(B),各因子的最优组合为A2B2C2D3,即以1∶3.5的料液比(m∶V),在35℃时浸泡3h后蒸馏2h为大蒜挥发油的最佳提取工艺,此时挥发油的提取率达到0.32%,证明此方法是大蒜挥发油提取的可靠、易行的科学方法。     

不同组分胶原多肽抗氧化作用的比较研究

研究发现:碱性蛋白酶+中性蛋白酶+木瓜蛋白酶三酶水解工艺(Ⅱ法)的胶原多肽中,小分子肽的比率较碱性蛋白酶+中性蛋白酶双酶水解(Ⅰ法)的胶原多肽要多;在浓度为12 mg/mL时,前者对DPPH·的清除率为78.71%,后者为57.05%;在40 mg/mL时,二者清除·OH的能力分别为27.37%和89.12%.在相同给药剂量时,Ⅱ法多肽提高小鼠GHS-Px活力和降低MDA和LF含量的效果明显优于Ⅰ法多肽.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.