Effect of ionizing radiation on antinutritional features of velvet bean seeds (Mucuna pruriens)

Impact of gamma irradiation on the antinutritional constituents of seeds of Mucuna pruriens was assessed on exposing to doses of 2.5, 5.0, 7.5, 10, 15 and 30 kGy. Except for 2.5 kGy, the rest showed significant dose-dependent increase in phenolics. Tannin concentration did not differ significantly up to 7.5 kGy, while it significantly increased at higher doses. Excluding 2.5 kGy, the rest of the treatments showed significant decreases in the phytic acid and complete degradation was attained at 15 and 30 kGy. The l-DOPA concentration showed a dose-dependent decline. A trace amount of hemagglutination activity was seen on human erythrocytes in raw seeds, which was completely absent on irradiation (>5 kGy). Concentration of Polonium-210, a natural radionuclide falls within the admissible limits for consumption. As Mucuna seeds serve as food, feed or as pharmaceuticals, it may be necessary to set the ionizing radiation to a specific dose to retain optimum levels or to eliminate phenolics, tannins, phytic acid and L-DOPA. As irradiation is a physical and cold process, it may be ideal and emerge as an important technique to improve the nutritional or pharmaceutical quality of Mucuna seeds and its products.     

左旋多巴改性MABR中空纤维膜

利用左旋多巴在碱性水溶液中的氧化交联成膜反应制备适于MABR过程的复合膜.通过浸泡法对多孔性聚丙烯中空纤维膜进行表面聚合改性,考察了左旋多巴的浓度、反应时间和溶液pH值对改性效果的影响.比较了改性前后膜的表面结构、水接触角及气体通量的变化.结果表明在1.5 g/L、pH=9.5的条件下,反应时间为7 h时,左旋多巴能在中空纤维表面形成一层稳定的无缺陷复合皮层,气体通量为0.3176 mL/(cm²·s),接触角为75.1°,在MABR测试实验中,复合膜的挂膜效果和处理能力均有较大提高.     

液相色谱-串联质谱法测定豆类中左旋多巴

文章建立一种豆类中左旋多巴的液相色谱-串联质谱测定方法。样品经0.3 mol/L乙酸水溶液超声提取,Agilent Proshell 120 SB-C18(2.1 mm×150 mm,2.7μm)色谱柱分离,以0.1%甲酸水-甲醇为流动相进行梯度洗脱,多反应监测(MRM),内标法定量。结果表明,左旋多巴在0.1~5.0 mg/L范围内线性关系良好,相关系数为0.9994,检出限为1.5 mg/kg,定量限为5.2 mg/kg,方法的平均加标回收率为96.9%~105.5%,日内精密度和日间精密度均小于4%,具有操作简单、灵敏度高、准确度高、重现性好等特点,能够很好满足豆类中左旋多巴含量的检测需要。     

Could Small Heat Shock Protein HSP27 Be a First-Line Target for Preventing Protein Aggregation in Parkinson’s Disease?

Small heat shock proteins (HSPs), such as HSP27, are ubiquitously expressed molecular chaperones and are essential for cellular homeostasis. The major functions of HSP27 include chaperoning misfolded or unfolded polypeptides and protecting cells from toxic stress. Dysregulation of stress proteins is associated with many human diseases including neurodegenerative diseases, such as Parkinson’s disease (PD). PD is characterized by the presence of aggregates of α-synuclein in the central and peripheral nervous system, which induces the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and in the autonomic nervous system. Autonomic dysfunction is an important non-motor phenotype of PD, which includes cardiovascular dysregulation, among others. Nowadays, the therapies for PD focus on dopamine (DA) replacement. However, certain non-motor symptoms with a great impact on quality of life do not respond to dopaminergic drugs; therefore, the development and testing of new treatments for non-motor symptoms of PD remain a priority. Since small HSP27 was shown to prevent α-synuclein aggregation and cytotoxicity, this protein might constitute a suitable target to prevent or delay the motor and non-motor symptoms of PD. In the first part of our review, we focus on the cardiovascular dysregulation observed in PD patients. In the second part, we present data on the possible role of HSP27 in preventing the accumulation of amyloid fibrils and aggregated forms of α-synuclein. We also include our own studies, highlighting the possible protective cardiac effects induced by L-DOPA treatment through the enhancement of HSP27 levels and activity.     

Adhesive Antimicrobial Peptides Containing 3,4-Dihydroxy-L-Phenylalanine Residues for Direct One-Step Surface Coating

Bacterial colonization and transmission via surfaces increase the risk of infection. In this study, we design and employ novel adhesive antimicrobial peptides to prevent bacterial contamination of surfaces. Repeats of 3,4-dihydroxy-L-phenylalanine (DOPA) were added to the C-terminus of NKC, a potent synthetic antimicrobial peptide, and the adhesiveness and antibacterial properties of the resulting peptides are evaluated. The peptide is successfully immobilized on polystyrene, titanium, and polydimethylsiloxane surfaces within 10 min in a one-step coating process with no prior surface functionalization. The antibacterial effectiveness of the NKC-DOPA₅-coated polystyrene, titanium, and polydimethylsiloxane surfaces is confirmed by complete inhibition of the growth of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus within 2 h. The stability of the peptide coated on the substrate surface is maintained for 84 days, as confirmed by its bactericidal activity. Additionally, the NKC-DOPA₅-coated polystyrene, titanium, and polydimethylsiloxane surfaces show no cytotoxicity toward the human keratinocyte cell line HaCaT. The antimicrobial properties of the peptide-coated surfaces are confirmed in a subcutaneous implantation animal model. The adhesive antimicrobial peptide developed in this study exhibits potential as an antimicrobial surface-coating agent for efficiently killing a broad spectrum of bacteria on contact.     

多巴类药物的研究进展

综述了甲基多巴和卡比多巴这2种多巴类药物的合成方法进展,全文涉及了18篇参考文献.     

一种小麦多酚氧化酶活性测定方法的改进研究

参照美国谷物化学家协会标准方法(AACC 22-85),以L-DOPA为底物,测定了22份小麦样品其籽粒的PPO活性,发现测定结果的重复性较差.在籽粒PPO活性测定原理的基础之上,优化了测定参数,改进、完善了一种评价小麦全粉PPO活性的新方法,其操作简便、快速,实验结果的重复性好、稳定性高,与籽粒PPO活性的测定结果极显著相关.     

小麦多酚氧化酶活性检测方法的比较分析

L-DOPA法是检测小麦多酚氧化酶(Polyphenol Oxidase,PPO)活性的标准方法(AACC 22-85),但L-DOPA试剂昂贵.为了寻求成本较低且准确的小麦PPO活性批量检测方法,以L-DOPA法为对照,采用了比色皿反应法和邻苯二酚法分别对24个小麦品种PPO活性进行了检测,并以196份小麦核心种质和部分应用核心种质为试材,对邻苯二酚法进行了验证.通过相关分析和方差分析,结果表明:比色皿反应法所测吸光度值在仪器误差范围内,可重复性较差,不能准确地反映品种间差异,故不宜采用;邻苯二酚法能准确地反映品种间差异,且可重复性好,是检测小麦PPO活性的理想方法.验证试验表明,邻苯二酚法和L-DOPA法的相关系数为0.984,且达极显著水平.以邻苯二酚代替L-DOPA,降低了小麦PPO活性检测费用,故邻苯二酚法是一种成本较低的、准确可靠的小麦PPO活性检测方法.     

LmbB2催化酪氨酸合成左旋多巴的工艺研究

左旋多巴是治疗帕金森病的首选药物,临床治疗中应用广泛。利用林可链霉菌的基因lmbB2构建了生产左旋多巴的大肠杆菌。在M9培养基添加酪氨酸300 mg/L和L-抗坏血酸3 g/L,在37 ℃下发酵32 h,左旋多巴产量达285 mg/L,转化率达到95%。     

Molecular Insights into SARS-CoV2-Induced Alterations of the Gut/Brain Axis

For a yet unknown reason, a substantial share of patients suffering from COVID-19 develop long-lasting neuropsychiatric symptoms ranging from cognitive deficits to mood disorders and/or an extreme fatigue. We previously reported that in non-neural cells, angiotensin-1 converting enzyme 2 (ACE2), the gene coding for the SARS-CoV2 host receptor, harbors tight co-expression links with dopa-decarboxylase (DDC), an enzyme involved in the metabolism of dopamine. Here, we mined and integrated data from distinct human expression atlases and found that, among a wide range of tissues and cells, enterocytes of the small intestine express the highest expression levels of ACE2, DDC and several key genes supporting the metabolism of neurotransmitters. Based on these results, we performed co-expression analyses on a recently published set of RNA-seq data obtained from SARS-CoV2-infected human intestinal organoids. We observed that in SARS-CoV2-infected enterocytes, ACE2 co-regulates not only with DDC but also with a specific group of genes involved in (i) the dopamine/trace amines metabolic pathway, (ii) the absorption of microbiota-derived L-DOPA and (iii) the absorption of neutral amino acids serving as precursors to neurotransmitters. We conclude that in patients with long COVID, a chronic infection and inflammation of small intestine enterocytes might be indirectly responsible for prolonged brain alterations.