Gut immunity in Lepidopteran insects

Lepidopteran insects constitute one of the largest fractions of animals on earth, but are considered pests in their relationship with man. Key to the success of this order of insects is its ability to digest food and absorb nutrition, which takes place in the midgut. Because environmental microorganisms can easily enter Lepidopteran guts during feeding, the innate immune response guards against pathogenic bacteria, virus and microsporidia that can be devoured with food. Gut immune responses are complicated by both resident gut microbiota and the surrounding peritrophic membrane and are distinct from immune responses in the body cavity, which depend on the function of the fat body and hemocytes. Due to their relevance to agricultural production, studies of Lepidopteran insect midgut and immunity are receiving more attention, and here we summarize gut structures and functions, and discuss how these confer immunity against different microorganisms. It is expected that increased knowledge of Lepidopteran gut immunity may be utilized for pest biological control in the future.     

辨桂枝与肉桂之异同

桂枝和肉桂同为樟科植物肉桂的一部分。桂枝为干燥的嫩枝,肉桂为干燥的树皮。虽然二者来源于同一植物,但是二者的功效主治却大相径庭。肉桂与桂枝都有发汗解热之功效。在桂枝汤中用肉桂或是桂枝,在发汗方面,二者无显著差别;而在解热方面,肉桂解热作用比桂枝强。肉桂和桂枝在功效与使用上有许多相似之处,但在某些方面也有差别,各味药都有其特殊而又精妙的用处。     

微透析采样考察麻黄-桂枝药对配伍对麻黄碱药代动力学的影响

目的:考察麻黄-桂枝药对配伍对麻黄碱药代动力学的影响。方法:通过考察流速、药物浓度等因素,确立适合麻黄碱微透析采样的技术条件。采用微透析采样技术,分别收集大鼠给予麻黄碱、麻黄和麻黄-桂枝药对配伍水煎液的血液透析液样品,通过LC-MS测定给药不同时间的麻黄碱浓度。采用DAS 3.0软件进行非房室模型拟合,比较不同给药组间的药动学差异。结果:麻黄碱微透析采样的技术条件为流速1.5μL·min~(-1),取样间隔20 min,样品质量浓度0.1~3.0 mg·L~(-1)。不同组别间药-时曲线下面积(AUC)无显著性差异。与麻黄碱组相比,麻黄-桂枝(3∶2)配伍组的达峰时间(T_(max))和药峰浓度(Cmax)均无显著性差异;消除半衰期(T1/2)和平均驻留时间(MRT)显著缩短,表观分布容积/生物利用度(VZ/F)显著降低,清除率/生物利用度(CLZ/F)显著增加。与麻黄组相比,配伍组C_(max)无显著性差异;T_(max)显著降低,T1/2和MRT显著缩短,VZ/F显著降低,CLZ/F显著增加。结论:麻黄-桂枝药对配伍后加速了麻黄碱在体内的代谢,可能是桂枝降低麻黄相对毒性的作用机制之一。     

HPLC法同时测定桑枝中6种成分的含量

[目的]建立高效液相色谱(HPLC)方法同时测定桑枝中桑皮苷A、绿原酸、隐绿原酸、芦丁、异槲皮苷和山奈酚含量。[方法]采用反相高效液相色谱(RP-HPLC)法,色谱柱为Agilent C18柱(4.6 mm×250 mm,5μm),流动相为水(含0.1%甲酸)-乙腈,以柱温25℃,梯度洗脱,检测波长为360 nm,流速1 mL/min,采用外标法计算桑枝中6种成分的含量。[结果]桑皮苷A、绿原酸、隐绿原酸、芦丁、异槲皮苷和山奈酚浓度分别在22.50~900.00、6.25~250.00、3.00~120.00、0.08~3.00、0.10~4.00及0.05~2.00μg/mL范围内与各自峰面积值呈良好的线性关系;稳定性实验RSD为1.04%~3.07%,重复性实验RSD为2.22%~4.70%,精密度实验RSD为1.34%~4.90%;平均加样回收率为97.4%~104.0%(RSD≤1.01%)。[结论]本法简便、准确、灵敏,为桑枝的质量控制提供有力依据。     

桂枝拮抗麻黄中枢氧化应激损伤及NLRP3炎症小体上调作用分析

目的:研究桂枝对麻黄中枢神经系统损伤的保护作用,并初步探讨其保护作用机制。方法:KM小鼠按体重随机分为生理盐水组,麻黄组(10 g·kg~(-1)),麻黄-桂枝3∶2组(10 g·kg~(-1)+6.67 g·kg~(-1)),麻黄-桂枝3∶1组(10 g·kg~(-1)+3.33 g·kg~(-1)),桂枝组(6.67 g·kg~(-1)),灌胃给药14 d,酶联免疫吸附(ELISA)法检测各组小鼠脑组织中超氧化物歧化酶(SOD),丙二醛(MDA),一氧化氮(NO),一氧化氮合酶(NOS)活性,蛋白免疫印迹法(Western blot)测定小鼠脑组织NLRP3炎症小体表达水平。结果:与生理盐水组比较,麻黄组小鼠SOD活力下降(P0.01),MDA,NO,TNOS,iNOS含量增加(P0.01),Nod样受体蛋白3(NLRP3),凋亡相关斑点样蛋白(ASC)和半胱氨酸天冬氨酸蛋白酶-1(Caspase-1)蛋白表达上调(P0.01),桂枝组无明显差异;与麻黄组比较,化学法结果显示麻黄-桂枝3∶2组和3∶1组均能够明显升高脑组织中SOD活力(P0.05,P0.01),降低MDA,NO,TNOS,iNOS含量(P0.05,P0.01),Western blot结果显示3∶2组能够显著降低NLRP3,ASC和Caspase-1蛋白表达(P0.05,P0.01),3∶1组能够降低Caspase-1蛋白表达(P0.05)。结论:桂枝对麻黄中枢神经系统损伤具有保护作用,且具有一定的量效关系,随着桂枝比例的增加,桂枝拮抗麻黄中枢毒性更为显著,其作用机制可能与其增加抗氧化活性,减少氧化应激损伤,抑制NLRP3炎症小体上调有关。     

Membrane-penetrating trehalase from silkworm Bombyx mori. Molecular cloning and localization in larval midgut

The main blood sugar in insects, trehalose, differs from glucose in mammals. To incorporate trehalose into cells and utilize it, tissue cells possess the enzyme trehalase (EC3.2.1.28), which catalyses trehalose into glucose, in the organellar membrane or in the cytoplasm. Soluble and membrane-bound trehalase proteins have been isolated from insects. To date, however, only genes encoding the soluble trehalase have been reported in insects. Soluble trehalase is therefore believed to become localized on the cell surface via modification. In contrast, cDNAs encoding trehalase localized on the apical cell surface via the glycosylphosphatidylinositol-anchor have been isolated from mammalian small intestines. The amino acid sequence contains a specific hydrophobic region and an upstream omega site, which is cleaved for glycosylphosphatidylinositol-attachment, at the C-terminus. Here, we describe a cDNA from the silkworm Bombyx mori that encodes a novel trehalase (type-2) with one transmembrane domain and lacking the omega site. Immunoblotting and immunohistochemical analyses demonstrated that in the midgut tissue of Bombyx larvae, soluble trehalase-1 is present mainly in goblet cell cavities, but membrane-bound trehalase-2 is predominantly seen on the visceral muscle surrounding the midgut. To our knowledge, this is the first report of a cDNA encoding trehalase that penetrates the cell membrane in insects and its cellular localization.     

A Bruch's membrane substitute fabricated from silk fibroin supports the function of retinal pigment epithelial cells in vitro

Silk fibroin provides a promising biomaterial for ocular tissue reconstruction, including the damaged outer blood–retinal barrier of patients afflicted with age‐related macular degeneration (AMD). The aim of the present study was to evaluate the function of retinal pigment epithelial (RPE) cells in vitro, when grown on fibroin membranes manufactured to a thickness similar to that of Bruch's membrane (3 µm). Confluent cultures of RPE cells (ARPE‐19) were established on fibroin membranes and maintained under conditions designed to promote maturation over 4 months. Control cultures were grown on polyester cell culture well inserts (Transwell^®). Cultures established on either material developed a cobblestone morphology, with partial pigmentation, within 12 weeks. Immunocytochemistry at 16 weeks revealed a similar distribution pattern between cultures for F‐actin, ZO‐1, ezrin, cytokeratin pair 8/18, RPE‐65 and Na⁺/K⁺‐ATPase. Electron microscopy revealed that cultures grown on fibroin displayed a rounder apical surface with a more dense distribution of microvilli. Both cultures avidly ingested fluorescent microspheres coated with vitronectin and bovine serum albumin (BSA), but not controls coated with BSA alone. VEGF and PEDF were detected in the conditioned media collected from above and below the two membrane types. Levels of PEDF were significantly higher than for VEGF on both membranes and a trend was observed towards larger amounts of PEDF in apical compartments. These findings demonstrated that RPE cell functions on fibroin membranes are equivalent to those observed for standard test materials (polyester membranes). As such, these studies support advancement to studies of RPE cell implantation on fibroin membranes in a preclinical model. Copyright © 2015 John Wiley & Sons, Ltd.     

Bmmar6, a second mori subfamily mariner transposon from the silkworm moth Bombyx mori

A second member of the divergent mori subfamily of mariner transposons, Bmmar6, is described from the silkworm moth Bombyx mori genome. A confident consensus sequence for Bmmar6 was obtained from a single genomic copy, 17 EST sequences, and the direct sequencing of a 'family' sequence from an amplification of all full-length genomic copies. Bmmar6 is most similar to Bmmar1 in the mori subfamily, which now also includes several fly and nematode transposons. These might be viewed as a discrete family of transposons within the IS630-Tc1-mariner superfamily with a distinctive D,D37D catalytic motif, and another small divergent D,D41D clade is recognized as their sister group of transposons.     

Biomolecular changes and somatic mutations induced by UV laser irradiation at embryonic stage of Bombyx mori

Purpose: To determine the impact of ultraviolet (UV) laser radiation on Bombyx mori embryos in terms of its effect on embryonic and larval haemolymph proteins and morphological traits.

Materials and methods: The eggs of silkworm strain NB₄D₂ were exposed to third harmonic laser pulses at 355 nm from a Nd:YAG laser for different durations of 30, 60, 90, 120, 150, or 180 sec. Morphological changes induced by the UV laser were analysed at larval, pupal and adult stages. The eggs exposed to UV laser irradiation at different developmental stages were subjected to protein analysis by sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS-PAGE). The haemolymph derived from irradiated and control larva was also analysed by SDS-PAGE.

Results: UV laser irradiation resulted in various structural polymorphisms. Asymmetrical fusion of segments was not confined to larva but persisted throughout pupal and adult stages. Development of extra caudal horn, unequal size and lack of antenna, retarded thoracic legs and variation in larval markings were observed. Comparatively, the effect of the UV laser on 8- and 16-h old embryo was greater than on the other stages. The changes in protein pattern were not distinct until the 5th day of embryogenesis as revealed by SDS-PAGE. A 178 kiloDalton (kDa) protein resolved into 198, 184 & 169 kDa polypeptides and 154 kDa new protein band along with other proteins of 110, 45, 41 & 38 kDa were noticed in irradiated eggs at the 6th day. Further, 33, 32, and 6.2 kDa new protein bands were observed in the haemolymph of 5th instar silkworm larvae derived from UV laser irradiated embryos.

Conclusions: A comparative analysis of the present study revealed that UV laser not only induced continuous structural polymorphisms (somatic mutations), but also induced protein changes with the appearance of new protein bands in embryonic and haemolymph protein. The UV laser could be a potential tool for biochemical genetics and genome analysis in B. mori.     

中药桂枝抑制黑素生成的作用机理研究

目的研究中药桂枝对小鼠黑素细胞系M el-a黑素生成、酪氨酸酶活性及基因表达的影响,阐明桂枝抑制黑素生成的机理。方法用药物处理M el-a细胞后进行黑素含量、L-DOPA染色、放免法测定酪氨酸酶活性,western b lot和实时RT-PCR分别测酪氨酸酶及酪氨酸酶相关蛋白的蛋白和mRNA表达水平。选取熊果苷作为阳性对照。结果10μg/m l浓度的桂枝提取物在细胞培养水平对黑素生成有明显地抑制作用,强于20μg/m l浓度的熊果苷。桂枝可以抑制酪氨酸酶mRNA表达;减少这种限速酶的蛋白产量,在细胞量相同的情况下,桂枝明显抑制酪氨酸酶的氧化活性。结论中药桂枝有很强的抑制黑素产生的作用,其作用是通过抑制酪氨酸酶的基因表达、蛋白合成和氧化活性这三方面来实现。