45 research outputs found
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Evaluation of the Immune Response of Patulin by Proteomics.
Patulin, an emerging mycotoxin with high toxicity, poses great risks to public health. Considering the poor antibody production in patulin immunization, this study focuses on the four-dimensional data-independent acquisition (4D-DIA) quantitative proteomics to reveal the immune response of patulin in rabbits. The rabbit immunization was performed with the complete developed antigens of patulin, followed by the identification of the immune serum. A total of 554 differential proteins, including 292 up-regulated proteins and 262 down-regulated proteins, were screened; the differential proteins were annotated; and functional enrichment analysis was performed. The differential proteins were associated with the pathways of metabolism, gene information processing, environmental information processing, cellular processes, and organismal systems. The functional enrichment analysis indicated that the immunization procedures mostly resulted in the regulation of biochemical metabolic and signal transduction pathways, including the biosynthesis of amino acid (glycine, serine, and threonine), ascorbate, and aldarate metabolism; fatty acid degradation; and antigen processing and presentation. The 14 key proteins with high connectivity included G1U9T1, B6V9S9, G1SCN8, G1TMS5, G1U9U0, A0A0G2JH20, G1SR03, A0A5F9DAT4, G1SSA2, G1SZ14, G1T670, P30947, P29694, and A0A5F9C804, which were obtained by the analysis of protein-protein interaction networks. This study could provide potential directions for protein interaction and antibody production for food hazards in animal immunization
The mHz quasi-regular modulations of 4U 1630--47 during its 1998 outburst
We present the results of a detailed timing and spectral analysis of the
quasi-regular modulation (QRM) phenomenon in the black hole X-ray binary 4U
1630--47 during its 1998 outburst observed by Rossi X-ray Timing Explore
(RXTE). We find that the 50-110 mHz QRM is flux dependent, and the QRM
is detected with simultaneous low frequency quasi-periodic oscillations
(LFQPOs). According to the behavior of the power density spectrum, we divide
the observations into four groups. In the first group, namely behavior A,
LFQPOs are detected, but no mHz QRM. The second group, namely behavior B, a QRM
with frequency above 88 mHz is detected and the 5 Hz and 7
Hz LFQPOs are almost overlapping. In the third group, namely behavior C, the
QRM frequency below 88 mHz is detected and the LFQPOs are significantly
separated. In the forth group, namely behavior D, neither QRM nor LFQPOs are
detected. We study the energy-dependence of the fractional rms, centroid
frequency, and phase-lag of QRM and LFQPOs for behavior B and C. We then study
the evolution of QRM and find that the frequency of QRM increases with
hardness, while its rms decreases with hardness. We also analyze the spectra of
each observation, and find that the QRM rms of behavior B has a positive
correlation with / . Finally, we give
our understanding for this mHz QRM phenomena.Comment: 14pages, 15 figure
In-orbit background simulation of a type-B CATCH satellite
The Chasing All Transients Constellation Hunters (CATCH) space mission plans
to launch three types of micro-satellites (A, B, and C). The type-B CATCH
satellites are dedicated to locating transients and detecting their
time-dependent energy spectra. A type-B satellite is equipped with lightweight
Wolter-I X-ray optics and an array of position-sensitive multi-pixel Silicon
Drift Detectors. To optimize the scientific payloads for operating properly in
orbit and performing the observations with high sensitivities, this work
performs an in-orbit background simulation of a type-B CATCH satellite using
the Geant4 toolkit. It shows that the persistent background is dominated by the
cosmic X-ray diffuse background and the cosmic-ray protons. The dynamic
background is also estimated considering trapped charged particles in the
radiation belts and low-energy charged particles near the geomagnetic equator,
which is dominated by the incident electrons outside the aperture. The
simulated persistent background within the focal spot is used to estimate the
observation sensitivity, i.e. 4.2210 erg cm s
with an exposure of 10 s and a Crab-like source spectrum, which can be
utilized further to optimize the shielding design. The simulated in-orbit
background also suggests that the magnetic diverter just underneath the optics
may be unnecessary in this kind of micro-satellites, because the dynamic
background induced by charged particles outside the aperture is around 3 orders
of magnitude larger than that inside the aperture.Comment: 24 pages, 13 figures, 7 tables, accepted for publication in
Experimental Astronom
Simulation Studies for the First Pathfinder of the CATCH Space Mission
The Chasing All Transients Constellation Hunters (CATCH) space mission is an
intelligent constellation consisting of 126 micro-satellites in three types (A,
B, and C), designed for X-ray observation with the objective of studying the
dynamic universe. Currently, we are actively developing the first Pathfinder
(CATCH-1) for the CATCH mission, specifically for type-A satellites. CATCH-1 is
equipped with Micro Pore Optics (MPO) and a 4-pixel Silicon Drift Detector
(SDD) array. To assess its scientific performance, including the effective area
of the optical system, on-orbit background, and telescope sensitivity, we
employ the Monte Carlo software Geant4 for simulation in this study. The MPO
optics exhibit an effective area of cm at the focal spot for 1 keV
X-rays, while the entire telescope system achieves an effective area of
cm at 1 keV when taking into account the SDD detector's detection
efficiency. The primary contribution to the background is found to be from the
Cosmic X-ray Background. Assuming a 625 km orbit with an inclination of
, the total background for CATCH-1 is estimated to be
counts s in the energy range of 0.5--4 keV. Based on
the background within the central detector and assuming a Crab-like source
spectrum, the estimated ideal sensitivity could achieve erg
cm s for an exposure of 10 s in the energy band of 0.5--4
keV. Furthermore, after simulating the background caused by low-energy charged
particles near the geomagnetic equator, we have determined that there is no
need to install a magnetic deflector
The invasion of tobacco mosaic virus RNA induces endoplasmic reticulum stress-related autophagy in HeLa cells
The ability of human cells to defend against viruses originating from distant species has long been ignored. Owing to the pressure of natural evolution and human exploration, some of these viruses may be able to invade human beings. If their ‘fresh’ host had no defences, the viruses could cause a serious pandemic, as seen with HIV, SARS (severe acute respiratory syndrome) and avian influenza virus that originated from chimpanzees, the common palm civet and birds, respectively. It is unknown whether the human immune system could tolerate invasion with a plant virus. To model such an alien virus invasion, we chose TMV (tobacco mosaic virus) and used human epithelial carcinoma cells (HeLa cells) as its ‘fresh’ host. We established a reliable system for transfecting TMV-RNA into HeLa cells and found that TMV-RNA triggered autophagy in HeLa cells as shown by the appearance of autophagic vacuoles, the conversion of LC3-I (light chain protein 3-I) to LC3-II, the up-regulated expression of Beclin1 and the accumulation of TMV protein on autophagosomal membranes. We observed suspected TMV virions in HeLa cells by TEM (transmission electron microscopy). Furthermore, we found that TMV-RNA was translated into CP (coat protein) in the ER (endoplasmic reticulum) and that TMV-positive RNA translocated from the cytoplasm to the nucleolus. Finally, we detected greatly increased expression of GRP78 (78 kDa glucose-regulated protein), a typical marker of ERS (ER stress) and found that the formation of autophagosomes was closely related to the expanded ER membrane. Taken together, our data indicate that HeLa cells used ERS and ERS-related autophagy to defend against TMV-RNA
EBV Promotes Human CD8+ NKT Cell Development
The reports on the origin of human CD8+ Vα24+ T-cell receptor (TCR) natural killer T (NKT) cells are controversial. The underlying mechanism that controls human CD4 versus CD8 NKT cell development is not well-characterized. In the present study, we have studied total 177 eligible patients and subjects including 128 healthy latent Epstein-Barr-virus(EBV)-infected subjects, 17 newly-onset acute infectious mononucleosis patients, 16 newly-diagnosed EBV-associated Hodgkin lymphoma patients, and 16 EBV-negative normal control subjects. We have established human-thymus/liver-SCID chimera, reaggregated thymic organ culture, and fetal thymic organ culture. We here show that the average frequency of total and CD8+ NKT cells in PBMCs from 128 healthy latent EBV-infected subjects is significantly higher than in 17 acute EBV infectious mononucleosis patients, 16 EBV-associated Hodgkin lymphoma patients, and 16 EBV-negative normal control subjects. However, the frequency of total and CD8+ NKT cells is remarkably increased in the acute EBV infectious mononucleosis patients at year 1 post-onset. EBV-challenge promotes CD8+ NKT cell development in the thymus of human-thymus/liver-SCID chimeras. The frequency of total (3% of thymic cells) and CD8+ NKT cells (∼25% of NKT cells) is significantly increased in EBV-challenged chimeras, compared to those in the unchallenged chimeras (<0.01% of thymic cells, CD8+ NKT cells undetectable, respectively). The EBV-induced increase in thymic NKT cells is also reflected in the periphery, where there is an increase in total and CD8+ NKT cells in liver and peripheral blood in EBV-challenged chimeras. EBV-induced thymic CD8+ NKT cells display an activated memory phenotype (CD69+CD45ROhiCD161+CD62Llo). After EBV-challenge, a proportion of NKT precursors diverges from DP thymocytes, develops and differentiates into mature CD8+ NKT cells in thymus in EBV-challenged human-thymus/liver-SCID chimeras or reaggregated thymic organ cultures. Thymic antigen-presenting EBV-infected dendritic cells are required for this process. IL-7, produced mainly by thymic dendritic cells, is a major and essential factor for CD8+ NKT cell differentiation in EBV-challenged human-thymus/liver-SCID chimeras and fetal thymic organ cultures. Additionally, these EBV-induced CD8+ NKT cells produce remarkably more perforin than that in counterpart CD4+ NKT cells, and predominately express CD8αα homodimer in their co-receptor. Thus, upon interaction with certain viruses, CD8 lineage-specific NKT cells are developed, differentiated and matured intrathymically, a finding with potential therapeutic importance against viral infections and tumors
Advances of Metabolomics in Fungal Pathogen–Plant Interactions
Plant disease caused by fungus is one of the major threats to global food security, and understanding fungus–plant interactions is important for plant disease control. Research devoted to revealing the mechanisms of fungal pathogen–plant interactions has been conducted using genomics, transcriptomics, proteomics, and metabolomics. Metabolomics research based on mass spectrometric techniques is an important part of systems biology. In the past decade, the emerging field of metabolomics in plant pathogenic fungi has received wide attention. It not only provides a qualitative and quantitative approach for determining the pathogenesis of pathogenic fungi but also helps to elucidate the defense mechanisms of their host plants. This review focuses on the methods and progress of metabolomics research in fungal pathogen–plant interactions. In addition, the prospects and challenges of metabolomics research in plant pathogenic fungi and their hosts are addressed
Wavelet-Based Dynamic Evaluation of Human Equilibrium Function under Passive Motion
The efficient evaluation of human equilibrium function is important for people with organs degradation and dysfunction. The traditional evaluation of static and dynamic equilibrium function seems efficient, but the prepared participants restricted the experimental results to be objective and genuine. For evaluating the equilibrium function efficiently, we propose a wavelet-based dynamic model of the human body using external excitation. Firstly, we introduce a local linearization method based on the second-order Taylor expansion for simplifying typical linear system model. Secondly, the continuous wavelet transform analysis is applied to process gravity-center data and estimate parameters of the dynamic model. Finally, the settled time of the systemic responding rapidity is evaluated. Furthermore, the index of the equilibrium ability is obtained. Experiment results show the validity and practicability of the proposed method
Quantitively Characterizing the Chemical Composition of Tailored Bagasse Fiber and Its Effect on the Thermal and Mechanical Properties of Polylactic Acid-Based Composites
Natural fiber reinforced polymer-based composites have been growing into a type of green composites. The properties of natural fiber reinforced polymer-based composites are closely related to the structure of natural fibers. Bagasse fiber (BF) is one of the most used natural fibers for preparing natural fiber reinforced polymer-based composites. However, few examples of previous research touch on the quantitatively characterization of structure of BF and its effect on the properties of BF reinforced polymer-based composites. In this work, four kinds of BF including untreated BF (UBF), alkali treated BF (ABF), BF modified by silane coupling agent (SBF), and BF modified combining alkali treatment with silane coupling agent (ASBF) were prepared and melting blended with polylactic acid (PLA) to prepare PLA/BF composites. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), thermogravimetry (TGA) and mechanical properties testing were used to characterize and analyze the structure and properties of modified BF and its reinforced PLA-based composites. Results showed that the used methods changed the structure of BF and their bonding modes. The surface energies of UBF, ABF, SBF, and ASBF were 19.8 mJ/m2, 34.7 mJ/m2, 12.3 mJ/m2, and 21.6 mJ/m2, respectively. The O/C ratios of UBF, ABF, SBF and, ASBF are 0.48, 0.53, 0.47, and 0.51. Due to the synergistic effect of alkali treatment and silane coupling agent modification on the surface chemical properties, the content of silicon elements on the surface of ASBF (4.15%) was higher than that of ASBF (2.38%). However, due to the destroying of alkali treatment on the microstructure of BF, the alkali treatment had no prominently synergetic effect with coupling agent modification on the mechanical properties of PLA/BF composites. Alkali treatment removed the small molecular compounds from BF, decreased its thermal stability, and increased the crystalline region and crystallinity of cellulose. Meanwhile, alkali treatment made BF fibrillated and increased its contactable active area with the coupling agents, but destructed the nature structure of BF. The silane coupling agent played a more important role than alkali treatment did in improving the interfacial compatibility of PLA/BF composites