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"Fan Xian"
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Vanadium dioxide-assisted broadband tunable terahertz metamaterial absorber
Tunable terahertz (THz) functional devices have exhibited superior performances due to the use of active materials, such as liquid crystals, graphene, and semiconductors. However, the tunable range of constitutive parameters of materials is still limited, which leads to the low modulation depth of THz devices. Here, we demonstrate a broadband tunable THz absorber based on hybrid vanadium dioxide (VO
2
) metamaterials. Unlike other phase change materials, VO
2
exhibits an insulator-to-metal transition characteristic and the conductivity can be increased by 4–5 orders of magnitude under external stimulus including electric fields, optical, and thermal pumps. Based on the unique transition character of VO
2
, the maximum tunable range of the proposed absorber can be realized from 5% to 100% by an external thermal excitation. Meanwhile, an absorption greater than 80% in a continuous range with a bandwidth about 2.0 THz can be obtained when VO
2
is in its metal phase at high temperature. Furthermore, the absorber is insensitive to the incident angle up to 50° and such a broadband THz absorber can be used in applications including imaging, modulating, cloaking, and so on.
Journal Article
The regulatory role of ZmSTOMAGEN1/2 in maize stomatal development is elucidated via gene editing and metabolic profiling
Stomatal development is mediated by EPIDERMAL PATTERNING FACTORs (EPFs), a family of secreted peptides including STOMAGEN/EPFL9 in Arabidopsis . To clarify the functional role of STOMAGEN orthologues in maize ( Zea mays ), we generated a double knockout mutant of ZmSTOMAGEN1 and ZmSTOMAGEN2 using CRISPR/Cas9 system. Comprehensive phenotypic analysis revealed that the zmstomagen1/2 mutant exhibited severe stomatal development defects, including complete absence of stomata between epidermal cells in stomatal lineage files and abnormal stomatal complexes with small lobed cells. These aberrant cells likely arose from failed asymmetric divisions of guard mother cells, ultimately preventing the formation of functional stomatal complexes. A double knockout of ZmSTOMAGEN1/2 reduced the expression of SPEECHLESS1 ( SPCH1 ), MUTE , SCREAM2 ( SCRM2 ), and STOMATAL DENSITY AND DISTRIBUTION1 ( SDD1 ), impairing stomatal initiation and cell fate transition in early stomatal lineage cells. The mutant displayed a lower stomatal density and index, leading to reduced net photosynthetic rate, transpiration rate, and stomatal conductance but increased water-use efficiency (WUE). Compared to the wild-type plants (HiII-A × HiII-B), the zmstomagen1/2 mutant exhibited significant alterations in phytohormone homeostasis. These included brassinosteroid metabolite imbalance (increased typhasterol, decreased castasterone) and differential gibberellin regulation (elevated GA4, reduced GA1). These hormonal perturbations suggest that impaired stomatal morphogenesis in zmstomagen1/2 mutants result from disrupted crosstalk between multiple hormonals signaling networks. Our findings reveal a crucial role for ZmSTOMAGEN1/2 in regulating cell fate decisions within the stomatal lineage and provide a potential strategy for enhancing WUE in maize by manipulating ZmSTOMAGEN1/2 expression.
Journal Article
An Insight into Diversity and Functionalities of Gut Microbiota in Insects
The gut microbiota has long been of research interests due to its nutritional importance for many insects. It has been demonstrated that diversity of gut microbiota in insects can be modulated by many factors, including habitats, feeding preference, etc. Besides, the community structure of gut microbiota could also be altered during the different life stages of host insects. With development of conventional culture-dependent technologies and advanced culture-independent technologies, comprehensive and deep understanding of the functions of gut microbiota and their relationship with host insects were achieved, especially for the nutrient metabolic process mediated by them. In this review, we summarized the gut microbiota composition, major methods for gut microbiota characterization, and vital nutrient metabolic process mediated by gut microbiota in different insects. The increasing knowledge on the modulation of gut microbiota will help us for the comprehension of the contribution of gut microbiota to the nutritional metabolism of insects, prompting their growth and health.
Journal Article
Serum metabolomics in chickens infected with Cryptosporidium baileyi
Background
Cryptosporidium baileyi
is an economically important zoonotic pathogen that causes serious respiratory symptoms in chickens for which no effective control measures are currently available. An accumulating body of evidence indicates the potential and usefulness of metabolomics to further our understanding of the interaction between pathogens and hosts, and to search for new diagnostic or pharmacological biomarkers of complex microorganisms. The aim of this study was to identify the impact of
C. baileyi
infection on the serum metabolism of chickens and to assess several metabolites as potential diagnostic biomarkers for
C. baileyi
infection.
Methods
Ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) and subsequent multivariate statistical analysis were applied to investigate metabolomics profiles in the serum samples of chickens infected with
C. baileyi
, and to identify potential metabolites that can be used to distinguish chickens infected with
C. baileyi
from non-infected birds.
Results
Multivariate statistical analysis identified 138 differential serum metabolites between mock- and
C. baileyi
-infected chickens at 5 days post-infection (dpi), including 115 upregulated and 23 downregulated compounds. These metabolites were significantly enriched into six pathways, of which two pathways associated with energy and lipid metabolism, namely glycerophospholipid metabolism and sphingolipid metabolism, respectively, were the most enriched. Interestingly, some important immune-related pathways were also significantly enriched, including the intestinal immune network for IgA production, autophagy and cellular senescence. Nine potential
C. baileyi
-responsive metabolites were identified, including choline, sirolimus, all-
trans
retinoic acid, PC(14:0/22:1(13Z)), PC(15:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), PE(16:1(9Z)/24:1(15Z)), phosphocholine, SM(d18:0/16:1(9Z)(OH)) and sphinganine.
Conclusions
This is the first report on serum metabolic profiling of chickens with early-stage
C. baileyi
infection. The results provide novel insights into the pathophysiological mechanisms of
C. baileyi
in chickens.
Graphic abstract
Journal Article
Characterization of ZmPMP3g function in drought tolerance of maize
The genes enconding proteins containing plasma membrane proteolipid 3 (PMP3) domain are responsive to abiotic stresses, but their functions in maize drought tolerance remain largely unknown. In this study, the transgenic maize lines overexpressing maize
ZmPMP3g
gene were featured by enhanced drought tolerance; increases in total root length, activities of superoxide dismutase and catalase, and leaf water content; and decreases in leaf water potential, levels of O
2
−·
and H
2
O
2
, and malondialdehyde content under drought. Under treatments with foliar spraying with abscisic acid (ABA), drought tolerance of both transgenic line Y7-1 overexpressing
ZmPMP3g
and wild type Ye478 was enhanced, of which Y7-1 showed an increased endogenous ABA and decreased endogenous gibberellin (GA) 1 (significantly) and GA3 (very slightly but not significantly) and Ye478 had a relatively lower ABA and no changes in GA1 and GA3.
ZmPMP3g
overexpression in Y7-1 affected the expression of multiple key transcription factor genes in ABA-dependent and -independent drought signaling pathways. These results indicate that
ZmPMP3g
overexpression plays a role in maize drought tolerance by harmonizing ABA-GA1-GA3 homeostasis/balance, improving root growth, enhancing antioxidant capacity, maintaining membrane lipid integrity, and regulating intracellular osmotic pressure. A working model on ABA-GA-Z
mPMP3g
was proposed and discussed.
Journal Article
ZmPGIP1 regulates stem strength by enhancing lignin and cellulose biosynthesis in Arabidopsis thaliana
Polygalacturonase inhibiting proteins (PGIPs) are typical leucine-rich repeat (LRR) proteins that inhibit the activity of polygalacturonase (PG) in pathogens, but their function in promoting to plant stem development has been less studied. In this study, the PGIP gene from Zea mays was cloned and heterologously expressed in Arabidopsis thaliana, and then the plant phenotypes were observed and a set of physiological and biochemical indicators were measured. The results indicate that the ZmPGIP1 protein is expressed both in the cell membrane and cell wall. Our research observed that the heterologous expression of ZmPGIP1 significantly increased the production of lignin, cellulose and hemicellulose in transgenic lines. The stems of transgenic plants also showed a thicker cortical tissue. The increase in lignin deposition observed during histochemical staining suggests that the ZmPGIP1 gene may improve plant mechanical strength. These were tightly associated with the upregulated expression of lignin/cellulose-synthesis genes (C4H, C3H, F5H, PAL1/3, CCR1, CAD1-3/9, CCOMT, MYB58, CESA1/10) to enhance plant cell wall strength in transgenic lines. Our findings provide new perspectives on the growth regulation mechanisms of PGIP proteins in plant cell walls and provide a potential candidate gene for breeding increased disease-resistance and higher cellulose production in plants.
Journal Article
PU.1 inhibition attenuates atrial fibrosis and atrial fibrillation vulnerability induced by angiotensin‐II by reducing TGF‐β1/Smads pathway activation
Fibrosis serves a critical role in driving atrial remodelling‐mediated atrial fibrillation (AF). Abnormal levels of the transcription factor PU.1, a key regulator of fibrosis, are associated with cardiac injury and dysfunction following acute viral myocarditis. However, the role of PU.1 in atrial fibrosis and vulnerability to AF remain unclear. Here, an in vivo atrial fibrosis model was developed by the continuous infusion of C57 mice with subcutaneous Ang‐II, while the in vitro model comprised atrial fibroblasts that were isolated and cultured. The expression of PU.1 was significantly up‐regulated in the Ang‐II‐induced group compared with the sham/control group in vivo and in vitro. Moreover, protein expression along the TGF‐β1/Smads pathway and the proliferation and differentiation of atrial fibroblasts induced by Ang‐II were significantly higher in the Ang‐II‐induced group than in the sham/control group. These effects were attenuated by exposure to DB1976, a PU.1 inhibitor, both in vivo and in vitro. Importantly, in vitro treatment with small interfering RNA against Smad3 (key protein of TGF‐β1/Smads signalling pathway) diminished these Ang‐II‐mediated effects, and the si‐Smad3‐mediated effects were, in turn, antagonized by the addition of a PU.1‐overexpression adenoviral vector. Finally, PU.1 inhibition reduced the atrial fibrosis induced by Ang‐II and attenuated vulnerability to AF, at least in part through the TGF‐β1/Smads pathway. Overall, the study implicates PU.1 as a potential therapeutic target to inhibit Ang‐II‐induced atrial fibrosis and vulnerability to AF.
Journal Article
Cassava AGPase genes and their encoded proteins are different from those of other plants
ADP-glucose pyrophosphorylase (AGPase) is a rate-limiting enzyme for starch synthesis. In this study, cassava AGPase genes (MeAGP) were analyzed based on six cultivars and one wild species. A total of seven MeAGPs was identified, including four encoding AGPase large subunits (MeAGPLs 1, 2, 3 and 4) and three encoding AGPase small subunits (MeA-GPSs 1, 2 and 3). The copy number of MeAGPs varied in cassava germplasm materials. There were 14 introns for MeAGPLs 1, 2 and 3, 13 introns for MeAGPL4, and 8 introns for other three MeAGPSs. Multiple conservative amino acid sequence motifs were found in the MeAGPs. There were differences in amino acids at binding sites of substrates and regulators among different MeAGP subunits and between MeAGPs and a potato AGPase small subunit (1YP2: B). MeAGPs were all located in chloroplasts. MeAGP expression was not only associated with gene copy number and types/combinations, regions and levels of the DNA methylation but was also affected by environmental factors with the involvement of various transcription factors in multiple regulation networks and in various cis-elements in the gene promoter regions. The MeAGP activity also changed with environmental conditions and had potential differences among the subunits. Taken together, MeAGPs differ in number from those of Arabidopsis, potato, maize, banana, sweet potato, and tomato.
Journal Article
Clonal Architecture of Secondary Acute Myeloid Leukemia
Whole-genome sequencing of samples from seven subjects with secondary acute myeloid leukemia identified somatic mutations. These data, together with genotype analysis of the antecedent myelodysplastic syndromes (MDS), revealed the clonal evolution of MDS and secondary AML.
The myelodysplastic syndromes, a heterogeneous group of diseases characterized by ineffective hematopoiesis, are the most common cause of acquired bone marrow failure in adults.
1
Secondary acute myeloid leukemia (AML) develops in approximately one third of persons with myelodysplastic syndromes.
2
Clinical discrimination between the myelodysplastic syndromes and secondary AML currently rests predominantly on cytomorphologic analysis, since patients with myelodysplastic syndromes have dysplastic hematopoiesis and a myeloblast count of less than 20%, whereas those with a myeloblast count of 20% or more have AML. Although considerable overlap exists between the spectrum of cytogenetic and molecular lesions seen in the two disorders, there . . .
Journal Article