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51.
52.
Our previous research on coprolite specimens from the mummies of Joseon Dynasty (1392–1910 CE) has revealed various species of parasite eggs. Herein, we added 2 new helminthic cases of human remains from Joseon-period graves in the Republic of Korea (Korea). The organic materials precipitated on the hip bones of 2 half-mummied cases (Goryeong and Gwangmyeong cases) were collected, rehydrated, and examined by a microscope. In the sample from Goryeong-gun (gun=County), ova of Trichuris trichiura, Clonorchis sinensis, and Metagonimus spp. were detected, and eggs of T. trichiura and A. lumbricoides were found from the sample of Gwangmyeong-si (si=City). By adding this outcome to the existing data pool, we confirm our previous estimates of Joseon-period parasite infection rates. The overall rates of A. lumbricoides, T. trichiura, and C. sinensis decreased dramatically from Joseon to the modern period. In Goryeong mummy specimen, we also found Metagonimus spp. eggs that has rarely been detected in archaeological samples so far.  相似文献   
53.
Mesenchymal stromal/stem cells (MSCs) have been widely tested against many diseases, with more than 1000 registered clinical trials worldwide. Despite many setbacks, MSCs have been approved for the treatment of graft-versus-host disease and Crohn disease. However, it is increasingly clear that MSCs exert their therapeutic functions in a paracrine manner through the secretion of small extracellular vesicles (sEVs) of 50–200 nm in diameter. Unlike living cells that can persist long-term, sEVs are non-living and non-replicative and have a transient presence in the body. Their small size also renders sEV preparations highly amenable to sterilization by filtration. Together, acellular MSC-sEV preparations are potentially safer and easier to translate into the clinic than cellular MSC products. Nevertheless, there are inherent challenges in the development of MSC-sEV drug products. MSC-sEVs are products of living cells, and living cells are sensitive to changes in the external microenvironment. Consequently, quality control metrics to measure key identity and potency features of MSC-sEV preparations have to be specified during development of MSC-sEV therapeutics. The authors have previously described quantifiable assays to define the identity of MSC-sEVs. Here the authors discuss requirements for prospective potency assays to predict the therapeutic effectiveness of the drug substance in accordance with International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines. Although potency assays should ideally reflect the mechanism of action (MoA), this is challenging because the MoA for the reported efficacy of MSC-sEV preparations against multiple diseases of diverse underlying pathology is likely to be complex and different for each disease and difficult to fully elucidate. Nevertheless, robust potency assays could be developed by identifying the EV attribute most relevant to the intended biological activity in EV-mediated therapy and quantifying the EV attribute. Specifically, the authors highlight challenges and mitigation measures to enhance the manufacture of consistent and reproducibly potent sEV preparations, to identify and select the appropriate EV attribute for potency assays despite a complex “work-in-progress” MoA and to develop assays likely to be compliant with regulatory guidance for assay validation.  相似文献   
54.
Since the identification of the apolipoprotein E (apoE) *ε4 allele as a major genetic risk factor for late-onset Alzheimer's disease, significant efforts have been aimed at elucidating how apoE4 expression confers greater brain amyloid-β (Aβ) burden, earlier disease onset and worse clinical outcomes compared to apoE2 and apoE3. ApoE primarily functions as a lipid carrier to regulate cholesterol metabolism in circulation as well as in the brain. However, it has also been suggested to interact with hydrophobic Aβ peptides to influence their processing in an isoform-dependent manner. Here, we review evidence from in vitro and in vivo studies extricating the effects of the three apoE isoforms, on different stages of the Aβ processing pathway including synthesis, aggregation, deposition, clearance and degradation. ApoE4 consistently correlates with impaired Aβ clearance, however data regarding Aβ synthesis and aggregation are conflicting and likely reflect inconsistencies in experimental approaches across studies. We further discuss the physical and chemical properties of apoE that may explain the inherent differences in activity between the isoforms. The lipidation status and lipid transport function of apoE are intrinsically linked with its ability to interact with Aβ. Traditionally, apoE-oriented therapeutic strategies for Alzheimer's disease have been proposed to non-specifically enhance or inhibit apoE activity. However, given the wide-ranging physiological functions of apoE in the brain and periphery, a more viable approach may be to specifically target and neutralise the pathological apoE4 isoform.  相似文献   
55.
对功能核酸概念的分析需要建立在对功能核酸研究的基础上,从内涵和外延两个方面来进行探析。从内涵来看,它是对具有特殊结构、执行特定生物功能的核酸分子的统称;从外延来看,它包括适体、核酸核酶、核糖开关、发光核酸、修饰核酸、功能核酸裁剪、核酸自组装、功能核酸纳米材料、核酸纳米酶、核酸药物、核酸补充剂以及DNA存储技术等。目前功能核酸已成功地应用于生物传感、生物成像、生物医学等诸多领域。对功能核酸这一概念进行了探讨,并尝试对其范畴、特点进行归纳总结,以期梳理和完善功能核酸的基本概念,促进该领域的进一步发展。  相似文献   
56.
We investigated the gene expression of matrix metalloproteinases-9 (MMP-9) and tissue inhibitors of matrix metalloproteinases-1 (TIMP-1) in peripheral blood cells from infected cattle with Mycobacterium avium subsp. paratuberculosis (Map) in the ELISA-negative subclinical stage compared with uninfected control cattle. Significant decreased MMP-9 expression and increased TIMP-1 expression were found in peripheral blood cells from Map-infected cattle after stimulation with Map lysate and Map purified protein derivative (PPD) than in control cattle by real-time RT-PCR analysis. In contrast to the uninfected controls, the activity of MMP-9 was also decreased in peripheral blood cell culture supernatants from Map-infected cattle at 24 hr after Map lysate and MapPPD stimulation by gelatin zymography analysis. As a result, the MMP-9 may play an important role in the development of Mycobacterium avium subsp. paratuberculosis disease.  相似文献   
57.
The ectoparasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is an important potential biological control agent for lepidopterous pests of stored products. We investigated the effects of long-term cold storage of diapausing and nondiapausing H. hebetor on their performance after cold storage. Mortality during storage increased with increasing storage duration, and the mortality of diapausing females was lower than that of nondiapausing females after 8, 12, and 16 weeks of storage. Longevity, egg laying, number of progeny produced, and time to 50% egg laying were all reduced, as compared with the culture females when parasitoids were reared at conditions that do not induce diapause. But, for females reared at 20 °C at conditions that induce diapause, all of these quality parameters did not differ from those of culture insects when the storage duration was 8 weeks or less. The percentage of female F1 offspring was always lower for cold stored insects than for the culture insects. Presence of a male after cold storage did not impact any of the quality parameters measured. Thus, rearing parasitoids at 20 °C and 10L:14D and then storing them for up to 8 weeks at 5 °C would produce parasitoids that are similar to culture parasitoids, except that the percentage of females is lower than that in the cultures (36% vs. 52%).  相似文献   
58.
59.
A nitrile hydratase (NHase) gene from Aurantimonas manganoxydans was cloned and expressed in Escherichia coli BL21 (DE3). A downstream gene adjacent to the β-subunit was necessary for the functional expression of the recombinant NHase. The structural gene order of the Co-type NHase was α-subunit beyond β-subunit, different from the order typically reported for Co-type NHase genes. The NHase exhibited adequate thermal stability, with a half-life of 1.5 h at 50 °C. The NHase efficiently hydrated 3-cyanopyridine to produce nicotinamide. In a 1-L reaction mixture, 3.6 mol of 3-cyanopyridine was completely converted to nicotinamide in four feedings, exhibiting a productivity of 187 g nicotinamide/g dry cell weight/h. An industrial auto-induction medium was applied to produce the recombinant NHase in 10-L fermenter. A glycerol-limited feeding method was performed, and a final activity of 2170 U/mL culture was achieved. These results suggested that the recombinant NHase was efficiently cloned and produced in E. coli.  相似文献   
60.

Background

Characterizing the biogeography of the microbiome of healthy humans is essential for understanding microbial associated diseases. Previous studies mainly focused on a single body habitat from a limited set of subjects. Here, we analyzed one of the largest microbiome datasets to date and generated a biogeographical map that annotates the biodiversity, spatial relationships, and temporal stability of 22 habitats from 279 healthy humans.

Results

We identified 929 genera from more than 24 million 16S rRNA gene sequences of 22 habitats, and we provide a baseline of inter-subject variation for healthy adults. The oral habitat has the most stable microbiota with the highest alpha diversity, while the skin and vaginal microbiota are less stable and show lower alpha diversity. The level of biodiversity in one habitat is independent of the biodiversity of other habitats in the same individual. The abundances of a given genus at a body site in which it dominates do not correlate with the abundances at body sites where it is not dominant. Additionally, we observed the human microbiota exhibit both cosmopolitan and endemic features. Finally, comparing datasets of different projects revealed a project-based clustering pattern, emphasizing the significance of standardization of metagenomic studies.

Conclusions

The data presented here extend the definition of the human microbiome by providing a more complete and accurate picture of human microbiome biogeography, addressing questions best answered by a large dataset of subjects and body sites that are deeply sampled by sequencing.  相似文献   
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