Studies on antiviral glycosides. II. Mode of action for virucidal effects on Sendai virus

Treatment of Sendai virus with $\text{p-(sec-}\text{butyl)-phenyl-6-chloro-6-deoxy-β-}\text{d}\text{-glucopyranoside}$, followed by freezing and thawing resulted in a loss of hemolytic and cell fusion activities as well as infectivity without affecting hemagglutinating and neuraminidase activities. The anti-hemolytic activity of this compound was reversed by the addition of phosphatidyl choline to the virus samples. $\text{p-}\text{Azidophenyl-6-chloro-6-deoxy-β-}\text{d}\text{-[}{}^3\text{H]glucopyranoside}$ was successfully used for photoaffinity labeling of a specific virion site, and we confirmed the affected site of the glucoside to be the lipid components in the viral envelopes.     

A microsporidium,Nosema pilicornis sp. n., of the purslane sawfly,Schizocerella pilicornis

A new microsporidian species, Nosema pilicornis, which infects the purslane sawfly, Schizocerella pilicornis, is described. This microsporidium infects most body tissues of the host. N. pilicornis was compared to other microsporidian species infecting Hymenoptera and to a group of similar microsporidia infecting Lepidoptera. N. pilicornis could be distinguished from all other microsporidian species on the basis of host range and ultrastructural characteristics of the spore. Spores were oval, containing 11 to 12 polar filament coils, and the polar filament had an angle of tilt of about 80°. N. pilicornis infected lepidopteran larvae, but only when heavy spore dosages were fed to early larval instars. S. pilicornis is a good but sporadic biological control agent of common purslane, Portulaca oleracea, a pernicious weed of vegetable, ornamental, and orchard crops. N. pilicornis, which is transovarially transmitted and causes high mortality in infected larvae, affects the performance of S. pilicornis as a biological control agent.     

The oxidation-reduction kinetics of the reaction of cytochrome c1 with non-physiological redox agents

The kinetics of the oxidation-reduction reactions of cytochrome c₁ with ascorbate, ferricyanide, triphenanthrolinecobalt(III) and N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) have been examined using the stopped-flow technique. The reduction of ferricytochrome c₁ by ascorbic acid is investigated as a function of pH. It is shown that at neutral and alkaline pH the reduction of the protein is mainly performed by the doubly deprotonated form of ascorbate. From the ionic-strength-dependence studies of the reactions of cytochrome c₁ with ascorbate, ferricyanide and triphenanthrolinecobalt(III), it is demonstrated that the reaction rate is governed by electrostatic interactions. The second-order rate constants for the reaction of cytochrome c₁ with ascorbate, ferricyanide, TMPD and triphenanthrolinecobalt(III) are 1.4·10⁴, 3.2·10³, 3.8·10⁴ and 1.3·10⁸ M^?1·s^?1 (pH 7.0, I = 0, 10°C), respectively. Application of the Debye-Hückel theory to the the ionic-strength-dependence studies of these redox reactions of cytochrome c₁ yielded for ferrocytochrome c₁ and ferricytochrome c₁ a net charge of ?5 and ?4, respectively. The latter value is close to that of ?3 for the oxidized enzyme, calculated from the amino acid sequence of the protein. This implies that not a local charge on the surface of the protein, but the overall net charge of cytochrome c₁ governs the reaction rate with small redox molecules.     

涉及光疗机制的生物光化学

本文对光生物和光化学的定义,反应机制的类型和光敏化作用等做了阐述。下面例举几个光疗的成果 1.光疗牛皮癣 经常使用的8-甲氧基补骨脂素在UVA的照射下,从基态被激发到三重态。它主要和DNA中的胸腺嘧啶,其次和色氨酸进行光环合加成,形成交联,阻止DNA和RNA的合成,抑制具过度增生 2.血卟啉衍生物(HPD)治癌 HPD有定位于癌组织的能力和光动力作用,可推断病人体内癌部位。 讨论了HPD的光疗机制,和酞菁相比,有各自的优缺点。 3.竹红菌素 主要治疗妇女外阴白色病变和疤痕疙瘩,抑制癌细胞生长。 讨论了竹红菌甲素和乙素及它们的氧化物的结构和活性。 在大于510nm的光照射下,也可抑制癌细胞的生长。列举了竹红菌素的优缺点。     

宁夏枸杞内生细菌的多样性及其抑菌活性研究

【目的】对宁夏枸杞各药用部位内生细菌的分布特征、遗传多样性和抑菌活性进行分析。【方法】采用菌落计数和16S rRNA基因序列分析法研究枸杞内生细菌的分布特征、遗传多样性,采用琼脂扩散法测定其抑菌活性。【结果】从各药用组织器官中分离出内生细菌34株,隶属于7科11属,内生细菌的数量和群落组成存在明显的组织特异性,其数量表现为根皮>叶>花>果实,而多样性则表现为花>根皮>叶>果实。芽孢杆菌属为枸杞优势内生菌群,分布于所有组织中;抑菌实验结果表明有76.5%的内生菌对一种或多种病原菌的生长有抑制作用,芽孢杆菌属菌株R2、R7、L3和短波单胞菌属的R3拮抗番茄炭疽杆菌和玉米大斑病菌的能力较强,而多数菌株对大肠杆菌和金黄色葡萄球菌的抑制能力较弱。【结论】枸杞可培养内生细菌遗传多样性丰富,对植物病原菌有较强的抑制活性。     

Green synthesis of zinc oxide nanoparticles using Anoectochilus elatus,and their biomedical applications

Zinc and its derivatives requirement increased to enhance human immunity against the different pandemics, including covid-19. Green synthesis is an emerging field of research. Zinc oxide (ZnO) nanoparticles have been prepared from Anoectochilus elatus and characterized using absorption, vibrational and electron microscope analysis. They were carried for antibacterial, inflammatory control tendency, and potential antioxidant activities. The brine shrimp lethal assay tested the biologically derived nanomaterial toxicity and the lethal concentration (LC₅₀) is 599.79 µg/ml. The inhibition against the important disease-causing pathogens was measured against four-gram negative, gram-positive bacteria and two fungus pathogens. The nanomaterial exposed inhibition zone for gram-positive bacteria between 17 mm and 25 mm. The inhibition zone against gram-negative bacteria exists between 19 mm and 24 mm. The anti-inflammatory activity was assessed by inhibition of protein denaturation and protease inhibitory activity using nanomaterial. The antioxidant activity was examined using four assays for the therapeutic activities. The average size range of 60–80 nm nanoparticles has prepared and exposed the good biological activity between 50 µg/ml and 100 µg/ml. The comparative results of anti-inflammatory and antioxidant assay results with standards such as Aspirin and vitamin C exposed that two to three times higher concentrations are required for the fifty percent of inhibitions. The prepared low-cost nanoparticle has exhibited excellent biological activity without any side effects and may enhance immunity.     

Silver nanostructures prepared via novel green approach as an effective platform for biological and environmental applications

Silver nanoparticles play a significant role in biomedical sciences due to their unique properties allowing for their use as an effective sensing and remediation platform Herein, the green synthesis of silver nanostructures (Ag NSs), prepared via aqueous extract of waste Brassica oleracea leaves in the presence of silver nitrate solution (10^-4 M), is reported. The Ag NSs are fully characterized and their efficacy with respect to 4-nitrophenol reduction, glucose sensing, and microbes is determined. Visually, the color of silver nitrate containing solution altered from colorless to yellowish, then reddish grey, confirming the formation of Ag NSs. HRTEM and SEAD studies revealed the Ag NSs to have different morphologies (triangular, rod-shaped, hexagonal, etc., within a size range of 20–40 nm) with face-centered cubic (fcc) crystal structure. The Ag NSs possess high efficacy for nitrophenol reduction (<11 min and degradation efficiency of 98.2%), glucose sensing (LOD: 5.83 µM), and antimicrobial activity (E. coli and B. subtilis with clearance zones of 18.3 and 14 mm, respectively). Thus, the current study alludes towards the development of a cost-effective, sustainable, and efficient three-in-one platform for biomedical and environmental applications.     

陕西食源性沙门氏菌耐药及相关基因

【目的】研究食源性沙门氏菌对常用抗生素的药敏性及相关耐药基因,更好的了解耐药性的产生和传播途径,确保食品安全。【方法】使用the Clinical and Laboratory Standards Institute推荐的琼脂稀释法测定沙门氏菌的药敏性,PCR和基因序列测定方法确定耐药沙门氏菌中整合子及其携带的耐药基因、与头孢菌素抗性相关的基因、沙门氏菌基因岛及与氟喹诺酮类抗生素耐药相关的基因突变。【结果】359株沙门氏菌中,67%的菌株对磺胺甲恶唑产生抗性,对甲氧苄啶/磺胺甲恶唑、四环素、卡那霉素、萘啶酮酸、氨苄西林、阿莫西林/克拉维酸、链霉素、氯霉素和庆大霉素、环丙沙星、头孢曲松、头孢西丁和头孢哌酮的耐药率分别为58%、56%、37%、35%、33%、32%、29%、26%、21%、16%、9%和8%。284株耐药菌中,79%的菌株可抗至少1种抗生素,25.9%可抗10种以上抗生素,2.5%可抗14种抗生素。耐药的Ⅰ类整合子以1.4kb最为常见,携带的耐药基因有aadA1、aadA2、aadA5、tetR、blaPSE-1、blaDHA-1、blaVEB-1、dhfrⅠ、dhfrⅤ、dhfrⅦ和dhfr17等。62株耐头孢曲松和/或头孢哌酮的沙门氏菌中,blaTEM和blaCMY-2基因的检出率分别为51.6%和56.5%。13.6%的沙门氏菌中检出了沙门氏菌基因岛。35株耐氟喹诺酮类抗生素的沙门氏菌的gyrA、parC和parE基因中共检出68个点突变,gyrA基因中常见突变为Ser83Phe、Ser83Tyr、Asp87Gly和Asp87Asn,parC基因中为Ser80Arg。parE基因中检出了Lys441Ile、Lys428Gln、Asp494Asn、Lys428Gln和Gly442Ser突变,这些点突变均为首次在食源性沙门氏菌中检出。【结论】陕西食源性沙门氏菌耐药状况严重,整合子、沙门氏菌基因岛和β-内酰胺酶编码基因的存在及解旋酶和拓扑异构酶基因突变是导致沙门氏菌耐药的重要机制。     

细菌素的合成与作用机制

细菌素是由细菌产生的抗菌蛋白,可以杀死与产生菌相近的细菌。很多乳酸菌产生不同多样性的细菌素,虽然这些细菌素都是由发酵或非发酵食品中发现的乳酸菌产生的,但是迄今只有乳酸链球菌素(Nisin)作为食品防腐剂被广泛应用。和抗生素不同的是,细菌素由核糖体合成,需经翻译后修饰活化并且通过特定转运系统输到胞外才能发挥其功能,它一般通过作用于靶细胞膜来抑制靶细胞的生长,同时本身合成细菌素的细胞对其产物具有免疫性。细菌素能安全有效地抑制病原体生长,在食品行业中具有广阔的应用前景。     

Establishment of ex vivo systems to identify compounds acting on innate immune responses and to determine their target molecules using transgenic Drosophila

Innate immunity is an evolutionarily conserved self-defense mechanism against microbial infections. In Drosophila, induction of antimicrobial peptides is a major immune response that is regulated by two distinct signaling pathways called the IMD pathway and the Toll pathway, similar to the tumor necrosis factor-alpha signaling and Toll-like receptor/interleukin-1 signaling pathways, respectively, in mammals. In mammals, innate immunity interacts with adaptive immunity and has a key role in the regulated immune response. Therefore, innate immunity is a pharmaceutical target for the development of immune regulators. Previously, based on the striking conservation between the mechanisms that regulate Drosophila immunity and human innate immunity, we established an ex vivo culture in which compounds acting on innate immunity can be evaluated using a reporter gene that reflects activation of the IMD pathway [Yajima et al. [Yajima, M., Takada, M., Takahashi, N., Kikuchi, H., Natori, S., Oshima, Y., Kurata, S., 2003. A newly established in vitro culture using transgenic Drosophila reveals functional coupling between the phospholipase A2-generated fatty acid cascade and lipopolysaccharide-dependent activation of the immune deficiency (imd) pathway in insect immunity. The Biochemical Journal 371(Pt 1), 205-210] Biochem J 371, 205-210]. Here, we combined the ex vivo culture with a reporter gene that reflects the heat shock response and demonstrated that the resulting systems are useful for screening compounds that act specifically on innate immunity, including mammalian innate immune responses. Identification of target molecules is essential for the development of more potent medicines with fewer side effects. In this study, we also established ex vivo systems capable of identifying target molecules of the identified compounds using targeted activation of the IMD pathway.