Published: 21 October 2020
Frontiers in Cellular and Infection Microbiology, Volume 10; doi:10.3389/fcimb.2020.565808.s004
Chlamydia pneumoniae is an obligate intracellular pathogen that causes diseases of the upper and lower respiratory tract and is linked to a number of severe and chronic conditions. Here, we describe a large, C. pneumoniae-specific cluster of 13 genes (termed mbp1-13) that encode highly homologous chlamydial proteins sharing the capacity to bind to membranes. The gene cluster is localized on the chromosome between the highly diverse adhesin-encoding pmp genes pmp15 and pmp14. Comparison of human clinical isolates to the predicted ancestral koala isolate indicates that the cluster was acquired in the ancestor and was adapted / modified during evolution. SNPs and IN/DELs within the cluster are specific to isolates taken from different human tissues and show an ongoing adaptation. Most of the cluster proteins harbor one or two domains of unknown function (DUF575 and DUF562). During ectopic expression in human cells these DUF domains are crucial for the association of cluster proteins to the endo-membrane system. Especially DUF575 which harbors a predicted transmembrane domain is important for binding to the membrane, while presence of the DUF562 seems to be of regulatory function. For Mbp1, founding member of the cluster that exhibits a very limited sequence identity to the human Rab36 protein, we found a specific binding to vesicles carrying the early endosomal marker PtdIns(3)P and the endosomal Rab GTPases Rab11 and Rab14. This binding is dependent on a predicted transmembrane domain with an α-helical / β-strand secondary structure, as the mutant version Mbp1mut, which lacks the β-strand secondary structure, shows a reduced association to PtdIns(3)P-positive membranes carrying Rab11 and Rab14. Furthermore, we could not only show that Mbp1 associates with Rab36, but found this specific Rab protein to be recruited to the early C. pneumoniae inclusion. Detection of endogenous Mbp1 and Mbp4 reveal a colocalization to the chlamydial outer membrane protein Momp on EBs. The same colocalization pattern with Momp was observed when we ectopically expressed Mbp4 in C. trachomatis. Thus, we identified a C. pneumoniae-specific cluster of 13 membrane binding proteins (Mbps) localizing to the bacterial outer membrane system.
Frontiers in Nutrition, Volume 7; doi:10.3389/fnut.2020.561010.s003
Poor dietary choices are major risk factors for obesity and non-communicable diseases, which places an increasing burden on healthcare systems worldwide. To monitor the effectiveness of healthy eating guidelines and strategies, there is a need for objective measures of dietary intake in community settings. Metabolites derived from specific foods present in urine samples can provide objective biomarkers of food intake (BFIs). Whilst the majority of biomarker discovery/validation studies have investigated potential biomarkers for single foods only, this study considered the whole diet by using menus that delivered a wide range of foods in meals that emulated conventional UK eating patterns. Fifty-one healthy participants (range 19–77 years; 57% female) followed a uniquely designed, randomized controlled dietary intervention, and provided spot urine samples suitable for discovery of BFIs within a real-world context. Free-living participants prepared and consumed all foods and drinks in their own homes and were asked to follow the protocols for meal consumption and home urine sample collection. This study also assessed the robustness, and impact on data quality, of a minimally invasive urine collection protocol. Overall the study design was well-accepted by participants and concluded successfully without any drop outs. Compliance for urine collection, adherence to menu plans, and observance of recommended meal timings, was shown to be very high. Metabolome analysis using mass spectrometry coupled with data mining demonstrated that the study protocol was well-suited for BFI discovery and validation. Novel, putative biomarkers for an extended range of foods were identified including legumes, curry, strongly-heated products, and artificially sweetened, low calorie beverages. In conclusion, aspects of this study design would help to overcome several current challenges in the development of BFI technology. One specific attribute was the examination of BFI generalizability across related food groups and across different preparations and cooking methods of foods. Furthermore, the collection of urine samples at multiple time points helped to determine which spot sample was optimal for identification and validation of BFIs in free-living individuals. A further valuable design feature centered on the comprehensiveness of the menu design which allowed the testing of biomarker specificity within a biobank of urine samples.
Frontiers in Physiology, Volume 11; doi:10.3389/fphys.2020.551318.s006
Myocardial ischemia–reperfusion (MI/R) injury is characterized by iron deposition and reactive oxygen species production, which can induce ferroptosis. Ferroptosis has also been proposed to promote cardiomyocyte death. The current study sought to define the mechanism governing cardiomyocyte death in MI/R injury. An animal model of MI/R was established by ligation and perfusion of the left anterior descending coronary artery, and a cellular model of IR was constructed in cardiomyocytes. ChIP assay was then conducted to determine the interaction among USP22, SIRT1, p53, and SLC7A11. Loss- and gain-of-function assays were also conducted to determine the in vivo and in vitro roles of USP22, SIRT1, and SLC7A11. The infarct size and pathological changes of myocardial tissue were observed using TCC and hematoxylin–eosin staining, and the levels of cardiac function– and myocardial injury–related factors of rats were determined. Cardiomyocyte viability and apoptosis were evaluated in vitro, followed by detection of ferroptosis-related indicators (glutathione (GSH), reactive oxygen species, lipid peroxidation, and iron accumulation). USP22, SIRT1, and SLC7A11 expressions were found to be down-regulated, whereas p53 was highly expressed during MI/R injury. USP22, SIRT1, or SLC7A11 overexpression reduced the infarct size and ameliorated pathological conditions, cardiac function, as evidenced by reduced maximum pressure, ejection fraction, maximum pressure rate, and myocardial injury characterized by lower creatine phosphokinase and lactate dehydrogenase levels in vivo. Moreover, USP22, SIRT1, or SLC7A11 elevation contributed to enhanced cardiomyocyte viability and attenuated ferroptosis-induced cell death in vitro, accompanied by increased GSH levels, as well as decreased reactive oxygen species production, lipid peroxidation, and iron accumulation. Together, these results demonstrate that USP22 overexpression could inhibit ferroptosis-induced cardiomyocyte death to protect against MI/R injury via the SIRT1/p53/SLC7A11 association.
Frontiers in Immunology, Volume 11; doi:10.3389/fimmu.2020.574330.s001
Over the last four decades, significant efforts have been invested to develop vaccines against malaria. Although most efforts are focused on the development of P. falciparum vaccines, the current availability of the parasite genomes, bioinformatics tools, and high throughput systems for both recombinant and synthetic antigen production have helped to accelerate vaccine development against the P. vivax parasite. We have previously in silico identified several P. falciparum and P. vivax proteins containing α-helical coiled-coil motifs that represent novel putative antigens for vaccine development since they are highly immunogenic and have been associated with protection in many in vitro functional assays. Here, we selected five pairs of P. falciparum and P. vivax orthologous peptides to assess their sero-reactivity using plasma samples collected in P. falciparum- endemic African countries. Pf-Pv cross-reactivity was also investigated. The pairs Pf27/Pv27, Pf43/Pv43, and Pf45/Pv45 resulted to be the most promising candidates for a cross-protective vaccine because they showed a high degree of recognition in direct and competition ELISA assays and cross-reactivity with their respective ortholog. The recognition of P. vivax peptides by plasma of P. falciparum infected individuals indicates the existence of a high degree of cross-reactivity between these two Plasmodium species. The design of longer polypeptides combining these epitopes will allow the assessment of their immunogenicity and protective efficacy in animal models.
Frontiers in Plant Science, Volume 11; doi:10.3389/fpls.2020.549636.s001
The accuracy of nitrogen (N) diagnosis is essential to improve N use efficiency. The standard critical N concentration (standard Nc) dilution curves, an expression of the dynamics of N uptake and dry matter accumulation in plants, are widely used to diagnose the N status of crops. Several standard Nc dilution curves were proposed and validated for several crops, based on experiments involving different N fertilizer treatments. However, standard Nc dilution curves are affected by crop water status, e.g., resulting from differences in irrigation management. This paper aimed at developing a N diagnostic model under the coupling effect of irrigation and fertilizer managements. For this purpose, Nc dilution curves were developed under different irrigation rates. Additionally, plant water content (PWC), leaf water content (LWC), leaf area index (LAI), equivalent water thickness (EWT), and leaf area duration (LAD) were introduced into the model, to construct a modified Nc (mNc) dilution curve. The mNc dilution curves were designed using the principle of hierarchical linear model (HLM), introducing aboveground dry biomass (AGB) as the first layer of information, whereas the second layer of information included the different agronomic variables (PWC, LWC, LAI, EWT, and LAD). The results showed that parameters “a” and “b” of the standard Nc dilution curves ranged from 5.17 to 6.52 and −0.69 to −0.38 respectively. Parameter “a” was easily affected by different management conditions. The performance of standard Nc dilution models obtained by the cross-validation method was worse than that of mNc dilution models. The Nc dilution curve based on 4 years of data was described by the negative power equation Nc = 5.05 × AGB–0.47, with R2 and nRMSE of 0.63 and 0.21, respectively. The mNc dilution curve considers different treatments and was represented by the equation mNc = a×AGB−b, where a = 2.09 × PWC + 3.24, b = −0.02 × LAI + 0.51, with R2 and nRMSE of 0.79 and 0.13, respectively. For winter wheat, C3 crop, there would be a few problems in using standard Nc dilution methods to guide field management, however, this study provides a reliable method for constructing mNc dilution curves under different water and N fertilizer management. Due to the significant differences in hereditary, CO2 fixation efficiency and N metabolism pathways for C3 and C4 crops, the construction of mNc dilution curve suitable for different N response mechanisms will be conducive to the sustainable N management in crop plants.
Frontiers in Microbiology, Volume 11; doi:10.3389/fmicb.2020.583745.s001
The present study was undertaken to produce probiotic Caciotta cheeses from pasteurized ewes’ milk by using different combinations of autochthonous microbial cultures, containing putative probiotic strains, and evaluate their influence on gross composition, lipid components, sensory properties and microbiological and metabolite profiles of the cheeses throughout ripening process. A control cheese was produced using commercial starter cultures. The hydrophilic molecular pools (mainly composed by amino acids, organic acids, and carbohydrates) were characterized by means of 1H NMR spectroscopy, while the cholesterol, α-tocopherol and fatty acid composition by HPLC-DAD/ELSD techniques. Conventional culturing and a PCR-DGGE approach using total cheese DNA extracts were used to analyze cheese microbiota and monitor the presence and viability of starters and probiotic strains. Our findings showed no marked differences for gross composition, total lipids, total cholesterol, and fatty acid levels among all cheeses during ripening. Differently, the multivariate statistical analysis of NMR data highlighted significant variations in the cheese’ profiles both in terms of maturation time and strains combination. The use of autochthonous cultures and adjunct probiotic strains did not adversely affect acceptability of the cheeses. Higher levels of lactobacilli (viability of 108–109 cfu/g of cheese) were detected in cheeses made with the addition of probiotic autochthonous strains with respect to control cheese during the whole ripening period, suggesting the adequacy of Caciotta cheese as a carrier for probiotic bacteria delivery.
Frontiers in Ecology and Evolution, Volume 8; doi:10.3389/fevo.2020.566281.s003
Invasive alien species (IAS) are known to be a major threat to biodiversity and ecosystem function and there is increasing evidence of their impacts on human health and economies globally. We undertook horizon scanning using expert-elicitation to predict arrivals of IAS that could have adverse human health or economic impacts on the island of Cyprus. Three hundred and twenty five IAS comprising 89 plants, 37 freshwater animals, 61 terrestrial invertebrates, 93 terrestrial vertebrates, and 45 marine species, were assessed during a two-day workshop involving 39 participants to derive two ranked lists: (1) IAS with potential human health impacts (20 species ranked within two bands: 1–10 species or 11–20 species); and, (2) IAS with potential economic impacts (50 species ranked in three bands of 1–10, 11–20, and 21–50). Five species of mosquitoes (Aedes aegypti, Aedes albopictus, Aedes flavopictus, Aedes japonicus, and Culex quinquefasciatus) were considered a potential threat to both human health and economies. It was evident that the IAS identified through this process could potentially arrive through many pathways (25 and 23 pathways were noted for the top 20 IAS on the human health and economic impact lists respectively). The Convention on Biological Diversity Level II (subcategory) pathways Contaminant on plants, pet/aquarium/terrarium species (including live food for such species), hitchhikers in or on aeroplanes, hitchhikers in or on ship/boats, and vehicles were the main pathways that arose across both lists. We discuss the potential of horizon scanning lists to inform biosecurity policies and communication around IAS, highlighting the importance of increasing understanding amongst all stakeholders, including the public, to reduce the risks associated with predicted IAS arrivals.
Frontiers in Oncology, Volume 10; doi:10.3389/fonc.2020.537247.s001
Objective: Triple-negative (PR−, ER−, HER-2−) breast cancer (TNBC) is regarded as more aggressive and more likely to recur after medical care. Emerging evidence has demonstrated that the circadian clock system regulates cell-signaling pathways critical to cancer cell proliferation, survival and metastasis, meaning that it could be a good candidate for TNBC treatment. As such, the aim of the current study was to examine the molecular mechanism by which the circadian clock system contributes to cancer progression in TNBC. Methods: Cancer cells and primary breast cancer tissues were immunostained for the measurement of circadian clock proteins (CLOCK, BMAL1 and PER1) and acetylserotonin methyltransferase (ASMT). The association between ASMT and clock proteins was assessed using siRNA and Western blot. Transwell assays were used to detect cancer cell migration and invasion while MTT assays were utilized to evaluate cell proliferation. Results: Circadian clock proteins (CLOCK, BMAL1, and PER1) and ASMT expression were higher in TNBC and triple positive breast cancer (TPBC) compared with para-carcinoma tissues (PCTs). Intriguingly, there was an obvious correlation between circadian clock proteins and ASMT expression in both TPBC and TNBC. Similarly, circadian clock proteins and ASMT were expressed to a greater extent in BT-474 (triple-positive) cells than in MDA-MB-231 (triple-negative) cells. The inhibition of ASMT reduced circadian clock protein levels in both breast cancer cell lines. Further analysis showed that the expression levels of ASMT and circadian clock proteins did not correlate with clinical parameters such as age, tumor size, histologic grade and CK5/6, but increased significantly with lymphatic invasion in TNBC. In agreement with this finding, knockdown of ASMT significantly leads to reductions in migration and invasion in MDA-MB-231 cells. However, over-expression of CLOCK reversed the decreases seen in ASMT inhibited cells. Conclusion: Our study suggests that ASMT regulates the circadian clock system in breast cancer and inhibition of ASMT reduces the invasiveness of triple-negative breast cancer cells by downregulating clock protein in a certain extent, indicating the potential value of ASMT as a drug target for TNBC treatment.
Frontiers in Cell and Developmental Biology, Volume 8; doi:10.3389/fcell.2020.581941.s002
Circular RNAs (circRNAs) have been increasingly demonstrated to play critical roles in the pathogenesis of various human diseases. Intervertebral disk degeneration (IDD) is recognized as the major contributor to lower back pain, and mechanical stress is a predominant trigger for IDD. However, little is known about the part that circRNAs play in the involvement of mechanical stress during IDD development. In the present study, we identified a novel circRNA and examined the role of this circRNA in a compression loading-induced IDD process. We detected the expression pattern of circCOG8 and observed its function in disk NP cells under mechanical stress. We conducted bioinformatics analysis, RNA immunoprecipitation experiment, and reporter gene assay to unveil the mechanism of the circCOG8 downregulation mediated IVD degeneration. Results showed that the circCOG8 expression was obviously down-regulated by the mechanical stress in disk NP cells. CircCOG8 attenuated NP cells apoptosis, intracellular ROS accumulation, and ECM degradation in vitro and ex vivo. CircCOG8 directly interacted with miR-182-5p and, thus, modulated the FOXO3 expression to affect the compression-induced IDD progression. Altogether, the present study revealed that the circCOG8/miR-182-5p/FOXO3 pathway was an important underlying mechanism in the involvement of compression during the IDD progression. Intervention of circCOG8 is a new therapeutic strategy for IDD treatment.
Frontiers in Human Neuroscience, Volume 14; doi:10.3389/fnhum.2020.581090.s001
Considerable variability exists in the publication of clinical research study procedures related to study enrollment and participant exit from clinical trials. Despite recent efforts to encourage research data sharing and greater transparency regarding research outcomes, reporting of research procedures remains inconsistent. Transparency about study procedures has important implications for the interpretation of study outcomes and the consistent implementation of best practices in clinical trial design and conduct. This review of publications from clinical trials of deep brain stimulation (DBS) using the MEDLINE database examines the frequency and consistency of publication of research procedures and data related to exit from DBS research. Related considerations, such as device explant or continued use, battery and other device hardware replacements, and post-trial follow-up care are also reviewed. This review finds significant variability in the publication and reporting of study exit procedures. Of the 47 clinical trials included in this review, 19% (9) disclosed procedures related to exit from research. Reporting of other exit-related data and study procedures examined in this review was identified in fewer than half of the included clinical trials. The rate of participant retention and duration of follow-up was reported more than any other category of data included in this review. Results inform efforts to improve consistency in research design, conduct, and publication of results from clinical trials in DBS and related areas of clinical research.