The occurrence of the second moult of Ascaris lumbricoides and Ascaris suum

Maung M. 1978. The occurrence of the second moult of Ascaris lumbricoides and Ascaris suum. International Journal for Parasitology 8: 371–378. Eggs of Ascaris lumbricoides and A. suum were cultured at 28°C and observed daily. Larvae were released by pressure, by artificial hatching with CO₂, and by natural hatching after infection of laboratory mice. The early stages of development in the egg were observed to comprise two moults, one occurring immediately after the other. Both moults were initiated within the egg, but the time of completion of the second moult varied considerably, and in some instances was not completed until the larvae reached the liver of experimentally infected animals.     

Quercetin supplementation does not alter antioxidant status in humans

Abstract

This study measured the influence of ingesting quercetin on plasma measures for oxidative stress and antioxidant capacity. Male and female subjects (n = 1002) varying in age (18–85 years) and body mass index (BMI) (16.7–52.7 kg/m²) were studied. Subjects were randomized to one of three groups using double-blinded methods: placebo, 500 mg or 1000 mg quercetin/day with 125 mg or 250 mg vitamin C/day, respectively. Pre- and post-study fasting blood samples show that plasma quercetin increased in a dose-responsive manner. The pattern of change in plasma F₂-isoprostanes, oxidized low density lipoprotein, reduced glutathione, ferric reducing ability of plasma (FRAP) and oxygen radical absorbance capacity (ORAC) did not differ between supplementation groups or after adjustment for gender, age, BMI and disease status. In summary, quercetin supplementation over 12 weeks in doses of 500 mg or 1000 mg/day significantly increased plasma quercetin levels, but had no influence on several measures of oxidative stress and antioxidant capacity.     

Mapping QTL for production traits in segregating Piétrain pig populations using genome‐wide association study results of F2 crosses

In this study, genome‐wide association study (GWAS) results of porcine F2 crosses were used to map QTL in outcross Piétrain populations. For this purpose, two F2 crosses (Piétrain × Meishan, n = 304; Piétrain × Wild Boar, n = 291) were genotyped with the PorcineSNP60v2 BeadChip and phenotyped for the dressing yield, carcass length, daily gain and drip loss traits. GWASs were conducted in the pooled F2 cross applying single marker mixed linear models. For the investigated traits, between two and five (in total 15) QTL core regions, spanning 250 segregating SNPs around a significant trait‐associated peak SNP, were identified. The SNPs within the QTL core regions were subsequently tested for trait association in two outcross Piétrain populations consisting of 771 progeny‐tested boars and 210 sows with their own performance records. In the sow (boar) dataset, five (eight) of the 15 mapped QTL were validated. Hence, many QTL mapped in the F2 crosses (with Piétrain as a common founder breed) are still segregating in the current Piétrain breed. This confirms the usefulness of existing F2 crosses for mapping QTL that are still segregating in the recent founder breed generation. The approach utilizes the high power of an F2 cross to map QTL in a breeding population for which it is not guaranteed that they would be found using a GWAS in this population.     

Enzymatic Engineering of Polysialic Acid on Cells in Vitro and in Vivo Using a Purified Bacterial Polysialyltransferase

In vertebrates, polysialic acid (PSA) is typically added to the neural cell adhesion molecule (NCAM) in the Golgi by PST or STX polysialyltransferase. PSA promotes plasticity, and its enhanced expression by viral delivery of the PST or STX gene has been shown to promote cellular processes that are useful for repair of the injured adult nervous system. Here we demonstrate a new strategy for PSA induction on cells involving addition of a purified polysialyltransferase from Neisseria meningitidis (PST_Nm) to the extracellular environment. In the presence of its donor substrate (CMP-Neu5Ac), PST_Nm synthesized PSA directly on surfaces of various cell types in culture, including Chinese hamster ovary cells, chicken DF1 fibroblasts, primary rat Schwann cells, and mouse embryonic stem cells. Similarly, injection of PST_Nm and donor in vivo was able to produce PSA in different adult brain regions, including the cerebral cortex, striatum, and spinal cord. PSA synthesis by PST_Nm requires the presence of the donor CMP-Neu5Ac, and the product could be degraded by the PSA-specific endoneuraminidase-N. Although PST_Nm was able to add PSA to NCAM, most of its product was attached to other cell surface proteins. Nevertheless, the PST_Nm-induced PSA displayed the ability to attenuate cell adhesion, promote neurite outgrowth, and enhance cell migration as has been reported for endogenous PSA-NCAM. Polysialylation by PST_Nm occurred in vivo in less than 2.5 h, persisted in tissues, and then decreased within a few weeks. Together these characteristics suggest that a PST_Nm-based approach may provide a valuable alternative to PST gene therapy.     

Histamine suppression of human lymphocyte responses to mitogens.

Exogenously added histamine in non-cytotoxic concentrations (10^?5?10^?3M) suppresses in vitro proliferation of lymphocytes induced by PHA or Concanavalin A. This suppressive effect was observed when histamine was present for as short as $\text{1}\text{2}$ hr in the beginning of the culture. Histamine, in concentrations as high as 10^?3M, did not cause increased release of isotope from ⁵¹Cr-labeled lymphocytes following 4 hr of incubation. The histamine H₂ receptor antagonist, metiamide, but not the H₁ receptor antagonists diphenhydramine or chlorpheniramine, blocked the histamine suppressive effect. Some of the biological implications of these findings are discussed.     

CircPRMT5 circular RNA promotes proliferation of colorectal cancer through sponging miR-377 to induce E2F3 expression

CircPRTM5 is associated with cell proliferation and migration in many kinds of malignancies. However, the functions and mechanisms of CircPRTM5 in CRC progression remain unclear. We explored the role and the mechanisms of CircPRTM5 in the development of CRC. Tissues of CRC patients and matched adjacent non-tumour tissues were collected to evaluate the expression of CircPRTM5. The expression of CircPRTM5 in CRC tissues was significantly higher than that in adjacent tissues. The biological functions of CircPRTM5 in CRC were determined by overexpression and down-regulation of CircPRTM5 in CRC cells in vitro and in vivo. The results indicate that knockdown of CircPRTM5 can significantly inhibit the proliferation of CRC cells. The potential mechanisms of CircPRTM5 in CRC development were identified by RT-qPCR, Western blotting analysis and luciferase reporter assay. CircPRTM5 competitively regulates the expression of E2F3 by capillary adsorption of miR-377. CircPRMT5 regulates CRC proliferation by regulating the expression of E2F3, which affects the expression of the cell cycle-associated proteins cyclinD1 and CDK2. CircPRTM5 exerts critical regulatory role in CRC progression by sponging miR-377 to induce E2F3 expression.     

去N端信号肽的水痘-带状疱疹病毒糖蛋白E的原核可溶性表达及其免疫原性评价

水痘-带状疱疹病毒(varicella zoster virus,VZV)糖蛋白E(glycoprotein E,gE)是VZV亚单位疫苗的主要候选蛋白,但目前原核表达系统制备的gE蛋白以包涵体形式为主,可溶性差。本研究采用去除第1～30氨基酸序列的VZV gE胞外域基因,将其与原核表达载体pET32a连接,并转化至感受态细胞BL21(DE3)中。使用异丙基-β-D-硫代半乳糖苷(Isopropylβ-D-thiogalactoside,IPTG)诱导表达,His-tag柱纯化重组gE蛋白,蛋白质印迹法(Western blot,WB)检测其特异性。用该重组gE蛋白免疫BALB/c小鼠制备多克隆抗体,酶联免疫吸附试验(enzyme linked immunosorbent assay,ELISA)和间接免疫荧光法检测多克隆抗体效价及特异性。结果显示,BL21/pET32a-VZV gE工程菌可以表达可溶性重组gE蛋白,纯化后纯度约为90%。WB鉴定该重组蛋白具有良好的免疫反应性。ELISA检测显示小鼠抗VZV gE多克隆抗体效价＞1∶10 000,间接免疫荧光实验结果显示该抗体特异性较高。结果表明,本研究在原核表达系统中成功表达可溶性重组VZV gE蛋白,同时该蛋白具有较强的免疫原性,这为VZV gE亚单位疫苗的研制和大规模生产奠定了基础。     

Phosphoproteomics identifies microglial Siglec‐F inflammatory response during neurodegeneration

Alzheimer’s disease (AD) is characterized by the appearance of amyloid‐β plaques, neurofibrillary tangles, and inflammation in brain regions involved in memory. Using mass spectrometry, we have quantified the phosphoproteome of the CK‐p25, 5XFAD, and Tau P301S mouse models of neurodegeneration. We identified a shared response involving Siglec‐F which was upregulated on a subset of reactive microglia. The human paralog Siglec‐8 was also upregulated on microglia in AD. Siglec‐F and Siglec‐8 were upregulated following microglial activation with interferon gamma (IFNγ) in BV‐2 cell line and human stem cell‐derived microglia models. Siglec‐F overexpression activates an endocytic and pyroptotic inflammatory response in BV‐2 cells, dependent on its sialic acid substrates and immunoreceptor tyrosine‐based inhibition motif (ITIM) phosphorylation sites. Related human Siglecs induced a similar response in BV‐2 cells. Collectively, our results point to an important role for mouse Siglec‐F and human Siglec‐8 in regulating microglial activation during neurodegeneration.