Deficiency in NDH-cyclic electron transport retards heat acclimation of photosynthesis in tobacco over day and night shift

In order to cope with the impact of global warming and frequent extreme weather, thermal acclimation ability is particularly important for plant development and growth, but the mechanism behind is still not fully understood. To investigate the role of NADH dehydrogenase-like complex (NDH) mediated cyclic electron flow (CEF) contributing to heat acclimation, wild type (WT) tobacco (Nicotiana tabacum) and its NDH-B or NDH-C, J, K subunits deficient mutants (ΔB or ΔCJK) were grown at 25/20°C before being shifted to a moderate heat stress environment (35/30°C). The photosynthetic performance of WT and ndh mutants could all eventually acclimate to the increased temperature, but the acclimation process of ndh mutants took longer. Transcriptome profiles revealed that ΔB mutant exhibited distinct photosynthetic-response patterns and stress-response genes compared to WT. Metabolite analysis suggested over-accumulated reducing power and production of more reactive oxygen species in ΔB mutant, which were likely associated with the non-parallel recovery of CO2 assimilation and light reactions shown in ΔB mutant during heat acclimation. Notably, in the warm night periods that could happen in the field, NDH pathway may link to the re-balance of excess reducing power accumulated during daytime. Thus, understanding the diurnal cycle contribution of NDH-mediated CEF for thermal acclimation is expected to facilitate efforts toward enhanced crop fitness and survival under future climates

NAT10 Maintains OGA mRNA Stability Through ac4C Modification in Regulating Oocyte Maturation

In vitro maturation (IVM) refers to the process of developing immature oocytes into the mature in vitro under the microenvironment analogous to follicle fluid. It is an important technique for patients with polycystic ovary syndrome and, especially, those young patients with the need of fertility preservation. However, as the mechanisms of oocyte maturation have not been fully understood yet, the cultivation efficiency of IVM is not satisfactory. It was confirmed in our previous study that oocyte maturation was impaired after N-acetyltransferase 10 (NAT10) knockdown (KD). In the present study, we further explored the transcriptome alteration of NAT10-depleted oocytes and found that O-GlcNAcase(OGA) was an important target gene for NAT10-mediated ac4C modification in oocyte maturation. NAT10 might regulate OGA stability and expression by suppressing its degradation. To find out whether the influence of NAT10-mediated ac4C on oocyte maturation was mediated by OGA, we further explored the role of OGA in IVM. After knocking down OGA of oocytes, oocyte maturation was inhibited. In addition, as oocytes matured, OGA expression increased and, conversely, O-linked N-acetylglucosamine (O-GlcNAc) level decreased. On the basis of NAT10 KD transcriptome and OGA KD transcriptome data, NAT10-mediated ac4C modification of OGA might play a role through G protein–coupled receptors, molecular transduction, nucleosome DNA binding, and other mechanisms in oocyte maturation. Rsph6a, Gm7788, Gm41780, Trpc7, Gm29036, and Gm47144 were potential downstream genes. In conclusion, NAT10 maintained the stability of OGA transcript by ac4C modification on it, thus positively regulating IVM. Moreover, our study revealed the regulation mechanisms of oocytes maturation and provided reference for improving IVM outcomes. At the same time, the interaction between mRNA ac4C modification and protein O-GlcNAc modification was found for the first time, which enriched the regulation network of oocyte maturation

Distinct miRNAs associated with various clinical presentations of SARS-CoV-2 infection.

MicroRNAs (miRNAs) have been shown to play important roles in viral infections, but their associations with SARS-CoV-2 infection remain poorly understood. Here, we detected 85 differentially expressed miRNAs (DE-miRNAs) from 2,336 known and 361 novel miRNAs that were identified in 233 plasma samples from 61 healthy controls and 116 patients with COVID-19 using the high-throughput sequencing and computational analysis. These DE-miRNAs were associated with SASR-CoV-2 infection, disease severity, and viral persistence in the patients with COVID-19, respectively. Gene ontology and KEGG pathway analyses of the DE-miRNAs revealed their connections to viral infections, immune responses, and lung diseases. Finally, we established a machine learning model using the DE-miRNAs between various groups for classification of COVID-19 cases with different clinical presentations. Our findings may help understand the contribution of miRNAs to the pathogenesis of COVID-19 and identify potential biomarkers and molecular targets for diagnosis and treatment of SARS-CoV-2 infection

Macroinvertebrate community structure, pollution tolerance, diversity and feeding functional groups in polluted urban rivers under different black and odorous levels

Macroinvertebrate community structure parameters can reflect the water quality and water ecosystem health status of rivers. In this paper, using the results of macroinvertebrates in 16 urban rivers in Sichuan Province from November 2020 to March 2021, we independently evaluated the level of black odor in urban rivers based on the mathematical model. On this basis, we examined the community structure, fouling tolerance, diversity, and feeding functional groups of macrobenthos in rivers with different degrees of black odor. During the study, a total of 39 species of macroinvertebrates were collected and identified to 3 phyla, 7 classes, 16 orders, 26 families and 30 genera. Urban rivers changed from non-black and non-odorous to black and odorous: (1) the dominant species, Chironomus flaviplumus, Physa fontinalis and Barbronia weberi, changed to Chironomus flaviplumus, a fouling-tolerant species with wide adaptability; (2) According to the tolerance values (TVs), the pollution resistance categories gradually increased as the level of black odor increased, which indicated the level of black odor in water bodies; (3) The calculation of the Hilsenhoff biotic indices (HBI) indicated that 83.3% of the sampled sites were moderately to heavily polluted. In general, the severity of water quality pollution in the black and odorous type of river was significantly higher than that in the non-black and odorous type of river, and with the deepening of the degree of blackness and odor the quality of the water deteriorated; (4) The community structure had an unstable community structure and a low diversity index of macroinvertebrate species; (5) The taxa of feeding functional groups shifted from the presence of all five types of feeding functional groups to the dominance of fouling-resistant species represented by scrapers. The results summarize the characteristics and change patterns of various indicators under different black-odorous degrees, indicating that the HBI can be used as an alternative indicator for the evaluation of black odorous water, and the number of species of Chironomidae can indicate the degree of black odor in water bodies

Insights into the Confined Crystallization in Microfluidics of Amorphous Calcium Carbonate

As a precursor phase, amorphous calcium carbonate (ACC) plays a key role in the formation of CaCO3 biominerals, but the detailed information about the structure evolution during the crystallization process of ACC is limited. Herein, based on the confined environment in microfluidics, we have demonstrated a strategy to investigate the crystallization processes of ACC. The characteristics of a confined environment in microfluidics were analyzed through COMSOL Multi physics simulations. By mixing equimolar CaCl2 and Na2CO3 aqueous solutions directly, the reactive crystallization of CaCO3 was monitored on chip by online microscope observation and micro Raman spectroscopy scanning. Combined with offline scanning electron microscopy characterization, we showed that branched aggregate ACC(I) precipitated first once mixing reactant solutions, then the more ordered and whiskerlike ACC(II) was an unexpected result. These whiskerlike ACC(II) either gradually transformed to spherical structure nanocrystalline, vaterite was then formed from it through spherulitic growth mechanism, or the initial rhombohedral crystallographic calcite was formed from whiskerlike ACC(II), then the complete rhombohedral calcite crystals formed through the dissolution/recrystallization of ACC(II). Our results showed an intuition-based way to directly observe the structure evolution of ACC crystallization in the confined environment; it could be of inspiration for the understanding of biomineralization processes.</p

Two-photon excited fluorescence emission from hemoglobin

Hemoglobin, one of the most important proteins in blood, is responsible for oxygen transportation in almost all vertebrates. Recently, we discovered two-photon excited hemoglobin fluorescence and achieved label-free microvascular imaging based on the hemoglobin fluorescence. However, the mechanism of its fluorescence emission still remains unknown. In this work, we studied the two-photon excited fluorescence properties of the hemoglobin subunits, heme/hemin (iron (II)/(III) protoporphyrin IX) and globin. We first studied the properties of heme and the similar spectral and temporal characteristics of heme and hemoglobin fluorescence provide strong evidence that heme is the fluorophore in hemoglobin. Then we studied the fluorescence properties of hemin, globin and methemoglobin, and found that the hemin may have the main effect on the methemoglobin fluorescence and that globin has tryptophan fluorescence like other proteins. Finally, since heme is a centrosymmetric molecule, that the Soret band fluorescence of heme and hemoglobin was not observed in the single photon process in the previous study may be due to the parity selection rule. The discovery of heme two-photon excited fluorescence may open a new window for heme biology research, since heme as a cofactor of hemoprotein has many functions, including chemical catalysis, electron transfer and diatomic gases transportation

Online stereovision calibration using on-road markings

Stereo vision helps autonomous vehicles a lot to complete the tasks such as obstacle avoidance, positioning and 3D reconstruction. However, the 6-DOF transform between the camera pair, which is necessary for 3D structure recovery, will not stay constant during the long-time working. In automobile applications, conventional calibration approaches that use man-made patterns are inconvenient and the existing self-calibration techniques cannot produce enough accurate calibration results. In this work, we propose a self-calibration method to recalibrate stereo rig automatically as well as precisely by utilizing on-road markings. First, the system detects crosswalks and extracts their corners in the two images respectively. Next, the system matches the extracted corners, both between the image pair and between images and the corner map. Finally, with matched corner pairs, the stereo transformation of the stereo rig will be estimated. Experiments show that the proposed approach could extract and match crosswalks&apos; corners accurately, and recalibrate sterevision system in terms of higher accuracy and robustness.EICPCI-S(ISTP)245-25

Measuring the urban sprawl based on economic-dominated perspective: the case of 31 municipalities and provincial capitals

ABSTRACTAccurate measurement of urban sprawl is vital for urban planning and management. Urban planning-induced internal structure complexity affects the extent of urban sprawl. In addition, urban sprawl is closely linked to economic development. The study attempts to explore the impact of urban sprawl from an economic-dominated perspective. Thus a City-Ring road-County (CRC) scale framework based on top-down administrative divisions for urban sprawl measurement is proposed: 1) the single-index measurement based on economic activity is applied to calculate urban sprawl; 2) the spatiotemporal pattern of urban sprawl is investigated through a case study in 31 economy-dominated provincial capital cities across China from 2005 to 2015; 3) the impact of economy and land on urban sprawl is explored using correlation analysis. The results indicate that the degree of urban sprawl at the city scale shows an “inverted U-shaped” curve from 2005 to 2015, which represents that the phenomenon of urban sprawl was most severe in 2010. It finds that urban sprawl was more severe in the east and central regions relative to the provincial capitals in the western region, with the situation being most severe in the northeast region. Regions that have been transformed from suburban to urban built-up areas need to be given priority attention by the local government, including population movement, land layout, and fiscal policy, to meet the criteria of the urbanization process. Through correlation analysis, we also found that urban sprawl was influenced by the industry structure and the form of built-up area. The outcome of the study suggests that the data scale is sufficiently small in granularity to provide geographic boundaries for systematic analysis of urban sprawl in multiple administrative regions. Thus, the study helps provide a reference for differential planning policy formulation by governments at diverse economic levels