Abolishing the prelamin A ZMPSTE24 cleavage site leads to progeroid phenotypes with near-normal longevity in mice.

Prelamin A is a farnesylated precursor of lamin A, a nuclear lamina protein. Accumulation of the farnesylated prelamin A variant progerin, with an internal deletion including its processing site, causes Hutchinson-Gilford progeria syndrome. Loss-of-function mutations in ZMPSTE24, which encodes the prelamin A processing enzyme, lead to accumulation of full-length farnesylated prelamin A and cause related progeroid disorders. Some data suggest that prelamin A also accumulates with physiological aging. Zmpste24-/- mice die young, at ∼20 wk. Because ZMPSTE24 has functions in addition to prelamin A processing, we generated a mouse model to examine effects solely due to the presence of permanently farnesylated prelamin A. These mice have an L648R amino acid substitution in prelamin A that blocks ZMPSTE24-catalyzed processing to lamin A. The LmnaL648R/L648R mice express only prelamin and no mature protein. Notably, nearly all survive to 65 to 70 wk, with ∼40% of male and 75% of female LmnaL648R/L648R mice having near-normal lifespans of 90 wk (almost 2 y). Starting at ∼10 wk of age, LmnaL648R/L648R mice of both sexes have lower body masses than controls. By ∼20 to 30 wk of age, they exhibit detectable cranial, mandibular, and dental defects similar to those observed in Zmpste24-/- mice and have decreased vertebral bone density compared to age- and sex-matched controls. Cultured embryonic fibroblasts from LmnaL648R/L648R mice have aberrant nuclear morphology that is reversible by treatment with a protein farnesyltransferase inhibitor. These novel mice provide a model to study the effects of farnesylated prelamin A during physiological aging.

Differential Transcription Profiling Reveals the MicroRNAs Involved in Alleviating Damage to Photosynthesis under Drought Stress during the Grain Filling Stage in Wheat.

To explore the possible novel microRNA (miRNA) regulatory pathways in Zhengmai 1860, a newly cultivated drought-tolerant wheat (Triticum aestivum L.) cultivar, miRNA transcriptome sequencing of the flag leaves of Zhengmai 1860, drought-sensitive variety Zhoumai 18, and drought-resistant variety Bainong 207 was performed during the grain filling stage. We also observed changes in the chloroplast ultrastructure, phytohormone levels, and antioxidant- and photosynthesis-related physiological indicators in three wheat varieties. The results showed that the flag leaves of the drought-tolerant variety Zhengmai 1860 had higher chlorophyll contents and net photosynthetic rates than those of Zhoumai 18 under drought stress during the grain filling stage; in addition, the chloroplast structure was more complete. However, there was no significant difference between Zhengmai 1860 and Bainong 207. MiRNA transcriptome analysis revealed that the differential expression of the miRNAs and mRNAs exhibited variable specificity. The KEGG pathway enrichment results indicated that most of the genes were enriched in the MAPK signaling pathway, plant hormone signal transduction, photosynthetic antennae protein, and amino acid and carbohydrate metabolism. In the drought-tolerant cultivar Zhengmai 1860, tae-miR408 was targeted to regulate the allene oxide synthase (AOS) gene, inhibit its expression, reduce the AOS content, and decrease the synthesis of jasmonic acid (JA) and abscisic acid (ABA). The results of this study suggest that Zhengmai 1860 could improve the photosynthetic performance of flag leaves by inhibiting the expression of genes involved in the JA pathway through miRNAs under drought conditions. Moreover, multiple miRNAs may target chlorophyll, antioxidant enzymes, phytohormone signal transduction, and other related pathways; thus, it is possible to provide a more theoretical basis for wheat molecular breeding.

Angiopoietin-like protein 3 promotes colorectal cancer progression and liver metastasis partly via the mitogen-activated protein kinase 14 pathway.

Colorectal cancer (CRC) remains one of the most common malignancies worldwide, and liver metastasis represents a considerable challenge during CRC treatment. Aberrant expression of angiopoietin-like protein 3 (ANGPTL3) has been reported in several human cancer types. However, the function and mechanism of ANGPTL3 in CRC remain unclear. In this study, we first explored ANGPTL3 expression profiles in CRC datasets from ONCOMINE and in local samples from patients with CRC. We then elucidated the function of ANGPTL3 via knockdown and overexpression experiments. Bioinformatic analyses were performed to investigate the biological function and associated molecular mechanisms of ANGPTL3 in CRC oncogenesis and development. Finally, a xenograft model of liver metastasis was used to determine the role of ANGPTL3 in CRC metastasis. Our findings indicated that ANGPTL3 expression was upregulated in human CRC tissues, with high ANGPTL3 expression significantly correlated with poor survival of patients with CRC. ANGPTL3 overexpression promoted the proliferation and migration of CRC cells partially through mitogen-activated protein kinase 14 (MAPK14), while ANGPTL3 silencing had the opposite effect. Moreover, ANGPTL3 downregulation suppressed tumor growth and liver metastasis in xenograft mice. Collectively, the results presented here indicate that ANGPTL3 promotes cell proliferation and liver metastasis partly via MAPK14, suggesting that ANGPTL3 plays a tumor-promoting role in CRC progression and thus may represent a therapeutic target for CRC treatment.

METTL3 regulates N6-methyladenosine modification of ANGPTL3 mRNA and potentiates malignant progression of stomach adenocarcinoma.

BACKGROUND: N6-methyladenosine (m6A) is associated with mammalian mRNA biogenesis, decay, translation and metabolism, and also contributes greatly to gastrointestinal tumor formation and development. Therefore, the specific mechanisms and signaling pathways mediated by methyltransferase-like 3 (METTL3), which catalyzes the formation of m6A chemical labeling in stomach adenocarcinoma (STAD), are still worth exploring. METHODS: Quantitative real-time PCR (qRT-PCR) was constructed to detect the expression of METTL3 in gastric cancer cell lines and patient tissues. The biological function of METTL3 was investigated in vitro/in vivo by Cell Counting Kit-8, colony formation assay, Transwell assay and nude mouse tumorigenesis assay. Based on the LinkedOmics database, the genes co-expressed with METTL3 in the TCGA STAD cohort were analyzed to clarify the downstream targets of METTL3. Methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) and RNA stability analysis were employed to explore the mechanism of METTL3 in gastric cancer progression. RESULTS: We analyzed TCGA data and found that METTL3 was frequently elevated in STAD, and demonstrated that METTL3 was present at high levels in clinical STAD tissues and cells. High METTL3 expression was more likely to have advanced TNM tumors and distant metastasis. On the other hand, METTL3 silencing effectively impeded the higher oncogenic capacity of AGS and HGC27 cells in vivo and in vitro, as reflected by slowed cell growth and diminished migration and invasion capacities. Continued mining of the TCGA dataset identified the co-expression of angiopoietin-like 3 (ANGPTL3) and METTL3 in STAD. Lower level of ANGPTL3 was related to increased level of METTL3 in STAD samples and shorter survival times in STAD patients. ANGPTL3 enrichment limited the growth and metastasis of STAD cells. Besides, ANGPTL3 mRNA levels could be decreased by METTL3-dominated m6A modifications, a result derived from a combination of MeRIP-qPCR and RNA half-life experiments. Importantly, the inhibitory effect of METTL3 silencing on cancer could be reversed to some extent by ANGPTL3 inhibition. CONCLUSIONS: Overall, our findings suggested that METTL3 functioned an oncogenic role in STAD by reducing ANGPTL3 expression in an m6A-dependent manner. The discovery of the METTL3-ANGPTL3 axis and its effect on STAD tumor growth will contribute to further studies on the mechanisms of gastric adenocarcinoma development.

A meta-analysis of the association between Helicobacter pylori infection and risk of hepatic encephalopathy.

BACKGROUND: Although the association between Helicobacter pylori (H. pylori) infection and hepatic encephalopathy (HE) has been confirmed through some research, the results of these relevant studies still remain controversial. We conducted an updated meta-analysis based on published studies to address this issue. METHODS: A systematic search was conducted, reviewing all studies about the association between H. pylori infection and HE, through November 2021. The outcome measures were presented as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: In total, 13 studies provided data from 2784 subjects. H. pylori infection increased the risk of HE by 32% (OR = 2.32, 95% CI: 1.78-3.04). The effect became greater after hepatic encephalopathy was divided into overt HE and minimal hepatic encephalopathy (MHE) (HE OR = 2.66, 95% CI: 2.01-3.51, MHE OR = 1.74, 95% CI: 1.10-2.76). After H. pylori eradication, the risk of HE was reduced by 64%. CONCLUSIONS: H. pylori infection is significantly associated with HE, and the infection rate of H. pylori also increases with the severity of HE. Eradication of H. pylori has a protective effect on HE. Therefore, it is necessary to eradicate H. pylori in HE treatments.

Overexpression of the Wheat TaPsb28 Gene Enhances Drought Tolerance in Transgenic Arabidopsis.

Psb28 is a soluble protein in the photosystem II (PSII) complex, but its role in the drought stress response of wheat remains unclear. Here, we functionally characterized the TaPsb28 gene, which positively regulates drought tolerance in wheat. When the full-length 546-bp TaPsb28 cDNA was transferred into Arabidopsis thaliana, it was located in the guard cell chloroplast around the stroma. Overexpression of TaPsb28 conferred drought tolerance, as exhibited by the increases in the survival rate. Transgenic plants maintained lower MDA content and higher chlorophyll content by inducing chlorophyll synthase (ChlG) gene transcription. The content of abscisic acid (ABA) and zeatin increased significantly in wild-type (WT) plants under drought stress, and the transcriptional expression levels of RD22, dihydroflavonol 4-reductase (DFR) and anthocyanin reductase (ANR) genes were induced, thus enhancing the contents of endogenous cyanidin, delphinidin, and proanthocyanidins. However, in transgenic plants, although anthocyanins were further aggregated, the ABA increase was inhibited, zeatin was restored to the control level under drought stress, and stomatal closure was promoted. These findings indicate ABA and zeatin have opposite synergistic effects in the process of drought tolerance caused by TaPsb28 because only after the effect of zeatin is alleviated can ABA better play its role in promoting anthocyanin accumulation and stomatal closure, thus enhancing the drought tolerance of transgenic plants. The results suggest that overexpression of TaPsb28 exerts a positive role in the drought response by influencing the functional metabolism of endogenous hormones. The understanding acquired through the research laid a foundation for further in-depth investigation of the function of TaPsb28 in drought resistance in wheat, especially its relationship with anthocyanidin accumulation.

Imbalanced nucleocytoskeletal connections create common polarity defects in progeria and physiological aging.

Studies of the accelerated aging disorder Hutchinson-Gilford progeria syndrome (HGPS) can potentially reveal cellular defects associated with physiological aging. HGPS results from expression and abnormal nuclear envelope association of a farnesylated, truncated variant of prelamin A called "progerin." We surveyed the diffusional mobilities of nuclear membrane proteins to identify proximal effects of progerin expression. The mobilities of three proteins-SUN2, nesprin-2G, and emerin-were reduced in fibroblasts from children with HGPS compared with those in normal fibroblasts. These proteins function together in nuclear movement and centrosome orientation in fibroblasts polarizing for migration. Both processes were impaired in fibroblasts from children with HGPS and in NIH 3T3 fibroblasts expressing progerin, but were restored by inhibiting protein farnesylation. Progerin affected both the coupling of the nucleus to actin cables and the oriented flow of the cables necessary for nuclear movement and centrosome orientation. Progerin overexpression increased levels of SUN1, which couples the nucleus to microtubules through nesprin-2G and dynein, and microtubule association with the nucleus. Reducing microtubule-nuclear connections through SUN1 depletion or dynein inhibition rescued the polarity defects. Nuclear movement and centrosome orientation were also defective in fibroblasts from normal individuals over 60 y, and both defects were rescued by reducing the increased level of SUN1 in these cells or inhibiting dynein. Our results identify imbalanced nuclear engagement of the cytoskeleton (microtubules: high; actin filaments: low) as the basis for intrinsic cell polarity defects in HGPS and physiological aging and suggest that rebalancing the connections can ameliorate the defects.

The Role of Plant Progesterone in Regulating Growth, Development, and Biotic/Abiotic Stress Responses.

Progesterone is a steroid hormone that performs important functions in mammals. However, studies on its physiological functions in plants have gradually increased in recent years. Therefore, this review summarizes the regulatory functions of progesterone on plant growth and development, as well as its response to stress. Moreover, the plant metabolic processes of progesterone are also discussed. Overall, progesterone is ubiquitous in plants and can regulate numerous plant physiological processes at low concentrations. Since progesterone shares similar characteristics with plant hormones, it is expected to become a candidate for plant hormone. However, most of the current research on progesterone in plants is limited to the physiological level, and more molecular level research is needed to clarify progesterone signaling pathways.

Postnatal development of mice with combined genetic depletions of lamin A/C, emerin and lamina-associated polypeptide 1.

Mutations in LMNA encoding lamin A/C and EMD encoding emerin cause cardiomyopathy and muscular dystrophy. Lmna null mice develop these disorders and have a lifespan of 7-8 weeks. Emd null mice show no overt pathology and have normal skeletal muscle but with regeneration defects. We generated mice with germline deletions of both Lmna and Emd to determine the effects of combined loss of the encoded proteins. Mice without lamin A/C and emerin are born at the expected Mendelian ratio, are grossly normal at birth but have shorter lifespans than those lacking only lamin A/C. However, there are no major differences between these mice with regards to left ventricular function, heart ultrastructure or electrocardiographic parameters except for slower heart rates in the mice lacking both lamin A/C and emerin. Skeletal muscle is similarly affected in both of these mice. Lmna+/- mice also lacking emerin live to at least 1 year and have no significant differences in growth, heart or skeletal muscle compared to Lmna+/- mice. Deletion of the mouse gene encoding lamina-associated protein 1 leads to prenatal death; however, mice with heterozygous deletion of this gene lacking both lamin A/C and emerin are born at the expected Mendelian ratio but had a shorter lifespan than those only lacking lamin A/C and emerin. These results show that mice with combined deficiencies of three interacting nuclear envelope proteins have normal embryonic development and that early postnatal defects are primarily driven by loss of lamin A/C or lamina-associated polypeptide 1 rather than emerin.

The iTRAQ-based chloroplast proteomic analysis of Triticum aestivum L. leaves subjected to drought stress and 5-aminolevulinic acid alleviation reveals several proteins involved in the protection of photosynthesis.

BACKGROUNDS: The perturbance of chloroplast proteins is a major cause of photosynthesis inhibition under drought stress. The exogenous application of 5-aminolevulinic acid (ALA) mitigates the damage caused by drought stress, protecting plant growth and development, but the regulatory mechanism behind this process remains obscure. RESULTS: Wheat seedlings were drought treated, and the iTRAQ-based proteomic approach was employed to assess the difference in chloroplast protein content caused by exogenous ALA. A total of 9499 peptides, which could be classified into 2442 protein groups, were identified with ≤0.01 FDR. Moreover, the contents of 87 chloroplast proteins was changed by drought stress alone compared to that of the drought-free control, while the contents of 469 was changed by exogenous ALA application under drought stress compared to that of drought stress alone. The Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis results suggested that the ALA pretreatment adjusted some biological pathways, such as metabolic pathways and pathways involved in photosynthesis and ribosomes, to enhance the drought resistance of chloroplasts. Furthermore, the drought-promoted H2O2 accumulation and O2- production in chloroplasts were alleviated by the exogenous pretreatment of ALA, while peroxidase (POD) and glutathione peroxidase (GPX) activities were upregulated, which agreed with the chloroplast proteomic data. We suggested that ALA promoted reactive oxygen species (ROS) scavenging in chloroplasts by regulating enzymatic processes. CONCLUSIONS: Our results from chloroplast proteomics extend the understanding of the mechanisms employed by exogenous ALA to defend against drought stress in wheat.

A Family of NAI2-Interacting Proteins in the Biogenesis of the ER Body and Related Structures.

Plants produce different types of endoplasmic reticulum (ER)-derived vesicles that accumulate and transport proteins, lipids, and metabolites. In the Brassicales, a distinct ER-derived structure called the ER body is found throughout the epidermis of cotyledons, hypocotyls, and roots. NAI2 is a key factor for ER body formation in Arabidopsis (Arabidopsis thaliana). Homologs of NAI2 are found only in the Brassicales and therefore may have evolved specifically to enable ER body formation. Here, we report that three related Arabidopsis NAI2-interacting proteins (NAIP1, NAIP2, and NAIP3) play a critical role in the biogenesis of ER bodies and related structures. Analysis using GFP fusions revealed that all three NAIPs are components of the ER bodies found in the cotyledons, hypocotyls, and roots. Genetic analysis with naip mutants indicates that they have a critical and redundant role in ER body formation. NAIP2 and NAIP3 are also components of other vesicular structures likely derived from the ER that are formed independent of NAI2 and are present not only in the cotyledons, hypocotyls, and roots, but also in the rosettes. Thus, while NAIP1 is a specialized ER body component, NAIP2 and NAIP3 are components of different types of ER-derived structures. Analysis of chimeric NAIP proteins revealed that their N-terminal domains play a major role in the functional specialization between NAIP1 and NAIP3. Unlike NAI2, NAIPs have homologs in all plants; therefore, NAIP-containing ER structures, from which the ER bodies in the Brassicales may have evolved, are likely to be present widely in plants.

Monitoring of PM2.5 Concentrations by Learning from Multi-Weather Sensors.

This paper aims to monitor the ambient level of particulate matter less than 2.5 µm (PM2.5) by learning from multi-weather sensors. Over the past decade, China has established a high-density network of automatic weather stations. In contrast, the number of PM monitors is much smaller than the number of weather stations. Since the haze process is closely related to the variation of meteorological parameters, it is possible and promising to calculate the concentration of PM2.5 by studying the data from weather sensors. Here, we use three machine learning methods, namely multivariate linear regression, multivariate nonlinear regression, and neural network, in order to monitor PM2.5 by exploring the data of multi-weather sensors. The results show that the multivariate linear regression method has the root mean square error (RMSE) of 24.6756 µg/m3 with a correlation coefficient of 0.6281, by referring to the ground truth of PM2.5 time series data; and the multivariate nonlinear regression method has the RMSE of 24.9191 µg/m3 with a correlation coefficient of 0.6184, while the neural network based method has the best performance, of which the RMSE of PM2.5 estimates is 15.6391 µg/m3 with the correlation coefficient of 0.8701.

Lamina-associated polypeptide 1 is dispensable for embryonic myogenesis but required for postnatal skeletal muscle growth.

Lamina-associated polypeptide 1 (LAP1) is an integral protein of the inner nuclear membrane that has been implicated in striated muscle maintenance. Mutations in its gene have been linked to muscular dystrophy and cardiomyopathy. As germline deletion of the gene encoding LAP1 is perinatal lethal, we explored its potential role in myogenic differentiation and development by generating a conditional knockout mouse in which the protein is depleted from muscle progenitors at embryonic day 8.5 (Myf5-Lap1CKO mice). Although cultured myoblasts lacking LAP1 demonstrated defective terminal differentiation and altered expression of muscle regulatory factors, embryonic myogenesis and formation of skeletal muscle occurred in both mice with a Lap1 germline deletion and Myf5-Lap1CKO mice. However, skeletal muscle fibres were hypotrophic and their nuclei were morphologically abnormal with a wider perinuclear space than normal myonuclei. Myf5-Lap1CKO mouse skeletal muscle contained fewer satellite cells than normal and these cells had evidence of reduced myogenic potential. Abnormalities in signalling pathways required for postnatal hypertrophic growth were also observed in skeletal muscles of these mice. Our results demonstrate that early embryonic depletion of LAP1 does not impair myogenesis but that it is necessary for postnatal skeletal muscle growth.

A mutation abolishing the ZMPSTE24 cleavage site in prelamin A causes a progeroid disorder.

In 1994 in the Journal of Cell Science, Hennekes and Nigg reported that changing valine to arginine at the endoproteolytic cleavage site in chicken prelamin A abolishes its conversion to lamin A. The consequences of this mutation in an organism have remained unknown. We now report that the corresponding mutation in a human subject leads to accumulation of prelamin A and causes a progeroid disorder. Next generation sequencing of the subject and her parents' exomes identified a de novo mutation in the lamin A/C gene (LMNA) that resulted in a leucine to arginine amino acid substitution at residue 647 in prelamin A. The subject's fibroblasts accumulated prelamin A, a farnesylated protein, which led to an increased percentage of cultured cells with morphologically abnormal nuclei. Treatment with a protein farnesyltransferase inhibitor improved abnormal nuclear morphology. This case demonstrates that accumulation of prelamin A, independent of the loss of function of ZMPSTE24 metallopeptidase that catalyzes processing of prelamin A, can cause a progeroid disorder and that a cell biology assay could be used in precision medicine to identify a potential therapy.

Effects of ZnO nanoparticle-coated packaging film on pork meat quality during cold storage.

BACKGROUND: There has been limited research on the use of ZnO nanoparticle-coated film for the quality preservation of pork meat under low temperature. In the present study, ZnO nanoparticles were mixed with sodium carboxymethyl cellulose (CMC-Na) to form a nanocomposite film, to investigate the effect of ZnO nanoparticle-coated film on pork meat quality and the growth of bacteria during storage under low temperature. RESULTS: When ZnO nanoparticle-coated film was used as the packaging material for pork meat for 14 days of cold storage at 4 °C, the results demonstrated a significant effect on restricting the increases in total volatile basic nitrogen and pH levels, limiting the decreases of lightness (increased L* value) and redness (increased a* value), and maintaining the water-holding capacity compared to the control pork samples (P < 0.05). The present study also discovered that the ZnO nanoparticle-coated film restrained the increase in total plate count (TPC). When Staphylococcus aureus was used as the representative strain, scanning electron microscopy revealed that ZnO nanoparticles increased the occurrence of cell membrane rupture under cold conditions. CONCLUSION: ZnO nanoparticle-coated film helps retain the quality of pork meat during cold storage by increasing the occurrence of microorganism injury. © 2016 Society of Chemical Industry.

Unveiling the mechanism of tuning elemental distribution in high entropy alloys and its effect on thermal stability.

The issue of elemental distribution such as chemical short range order (SRO) in high entropy alloys (HEAs) has garnered increased attention in both experimental and theoretical realms. A comprehensive and urgently required elucidation of this atomic-level phenomenon is the focus of this study. In this work, we systematically analyzed atomic-level information, involving atomic volume, charge transfer, local chemical ordering and atomic stress in 3d HEAs. We assess the hotly debated issue by attributing it to Cr atoms with negative atomic stress in the sublattice site, whereas other atoms with positive atomic stress have larger electronegativity and greater atomic volume, through which the interplay of positive and negative atomic stresses balances the local atomic environment. Additionally, we assume that Mn promotes the homogeneity of the HEA and the temperature-dependent chemical SRO enhances the thermal stability of HEAs. Our work contributes to advancing our understanding of the mechanistic aspects of elemental distribution in HEAs and their thermodynamic implications.

Genome-wide analysis and identification of Carotenoid Cleavage Oxygenase (CCO) gene family in coffee (coffee arabica) under abiotic stress.

The coffee industry holds importance, providing livelihoods for millions of farmers globally and playing a vital role in the economies of coffee-producing countries. Environmental conditions such as drought and temperature fluctuations can adversely affect the quality and yield of coffee crops.Carotenoid cleavage oxygenases (CCO) enzymes are essential for coffee plants as they help break down carotenoids contributing to growth and stress resistance. However, knowledge about the CCO gene family in Coffee arabica was limited. In this study identified 21 CCO genes in Coffee arabica (C. arabica) revealing two subfamilies carotenoid cleavage dioxygenases (CCDs) and 9-cis-epoxy carotenoid dioxygenases (NCED) through phylogenic analysis. These subfamilies exhibited distribution patterns in terms of gene structure, domains, and motifs. The 21 CaCCO genes, comprising 5 NCED and 16 CCD genes were found across chromosomes. Promoter sequencing analysis revealed cis-elements that likely interact with plant stress-responsive, growth-related, and phytohormones, like auxin and abscisic acid. A comprehensive genome-wide comparison, between C. arabica and A. thaliana was conducted to understand the characteristics of CCO genes. RTqPCR data indicated that CaNCED5, CaNCED6, CaNCED12, and CaNCED20 are target genes involved in the growth of drought coffee plants leading to increased crop yield, in a conditions, with limited water availability. This reveals the role of coffee CCOs in responding to abiotic stress and identifies potential genes useful for breeding stress-resistant coffee varieties.

Adsorption-induced restructuring and early stages of carbon-nanotube growth on Ni nanoparticles.

Carbon adsorption on various Ni surfaces is investigated as a function of coverage via a combination of first-principles simulations and field emission microscope experiments. It is found that carbon can be efficiently stored as subsurface carbides, but with different energetics on differently oriented surfaces depending on their compactness and density of adsorption sites. In the resulting morphological reshaping, {113} facets are predicted to grow at the expense of {111} and {100} facets, in excellent agreement with experimental observations. Moreover, at high coverage on the {113} surface the carbon adsorption energy passes through a maximum after which a structural crossover is realized such that carbon atoms tend to ascend to the surface to form one-dimensional chains (which are the precursors of graphitic nanostructures). This rationalizes the experimental observation of an incubation time between carbon storage and the beginning of catalytic growth, and provides insight into the early stages (nucleation mechanism) of carbon nanotubes on Ni nanoparticles.

A mouse model and pathogenesis study for CVA19 first isolated from hand, foot, and mouth disease.

ABSTRACTCoxsackievirus A19 (CVA19) is a member of Enterovirus (EV) C group in the Picornaviridae family. Recently, we reported a case of CVA19-infected hand, foot, and mouth disease (HFMD) for the first time. However, the current body of knowledge on the CVA19 infection, particularly the pathogenesis of encephalomyelitis and diarrhoea is still very limited, due to the lack of suitable animal models. Here, we successfully established a CVA19 mouse model via oral route based on 7-day-old ICR mice. Our results found the virus strain could directly infect the neurons, astrocytes of brain, and motor neurons of spinal cord causing neurological complications, such as acute flaccid paralysis. Importantly, viruses isolated from the spinal cords of infected mice caused severe illness in suckling mice, fulfilling Koch's postulates to some extent. CVA19 infection led to diarrhoea with typical pathological features of shortened intestinal villi, increased number of secretory cells and apoptotic intestinal cells, and inflammatory cell infiltration. Much higher concentrations of serum cytokines and more peripheral blood inflammatory cells in CVA19-infected mice indicated a systematic inflammatory response induced by CVA19 infection. Finally, we found ribavirin and CVA19 VP1 monoclonal antibody could not prevent the disease progression, but higher concentrations of antisera and interferon alpha 2 (IFN-α2) could provide protective effects against CVA19. In conclusion, this study shows that a natural mouse-adapted CVA19 strain leads to diarrhoea and encephalomyelitis in a mouse model via oral infection, which provides a useful tool for studying CVA19 pathogenesis and evaluating the efficacy of vaccines and antivirals.

Effect of postharvest 1-methylcyclopropene application on reactive oxygen species scavenging and sucrose metabolism in Gynura bicolor DC.

After harvest, the metabolism of Gynura bicolor DC (G. bicolor) is vigorous, resulting in sugar scarcity and reactive oxygen species (ROS) accumulation, thus aggravating the quality deterioration. 1-Methylcyclopropene (1-MCP) shows crucial effect in alleviating the postharvest metabolism of vegetables and fruits. This research aimed to evaluate the effect of 1-MCP on ROS scavenging and sucrose metabolism in G. bicolor. In this research, G. bicolor was treated with 10 µL L-1 1-MCP for 12 h, followed by storage at 20 ± 2 °C and 90 ± 5% relative humidity in darkness for 7 days. During storage, the increases in the respiration rate, electrolytic leakage, weight loss rate, ROS levels, and membrane lipid oxidation were effectively inhibited by 1-MCP. Moreover, starch and hexose degradation was decreased in the 1-MCP group, as were sucrose synthesis and catabolism. Correlation analysis indicated that sugar starvation was associated with respiration, activities regulation of CAT, SOD, and enzymes involved in sucrose metabolism were associated with the levels of hydrogen peroxide at the early storage. In conclusion, 1-MCP delayed postharvest quality deterioration of G. bicolor by alleviating respiration, inducing oxidative stress to enhance ROS scavenging, and inhibiting sucrose metabolism.