Vacuum-Based Agroinfiltration for Transient Gene Expression in Arabidopsis Seedlings.

Agrobacterium-mediated transient expression is a flexible and efficient technique for introducing genes into plants, allowing for rapid and temporary gene expression. Agroinfiltration of Arabidopsis seedlings is a newly developed Agrobacterium-based transient expression system. The expression of target genes and the localization of relevant proteins can be observed within 3 days using this method. In this chapter, we present the detailed protocol for transient transformation in Arabidopsis thaliana seedlings utilizing vacuum infiltration of Agrobacterium. This procedure enables rapid and temporary gene expression by introducing exogenous DNA into Arabidopsis seedlings, particularly in easily accessible tissues such as cotyledons. This protocol provides a detailed description of experimental procedures, including Arabidopsis seedlings cultivation, the preparation of Agrobacterium suspensions, and subsequent steps leading to confocal microscope observation. Through this protocol, researchers can efficiently investigate gene function and subcellular localization in Arabidopsis cotyledons within 8 days in total.

Rational design of CT-coupled J-aggregation platform based on Aza-BODIPY for highly efficient phototherapy.

Supramolecular engineering is exceptionally appealing in the design of functional materials, and J-aggregates resulting from noncovalent interactions offer intriguing features. However, building J-aggregation platforms remains a significant challenge. Herein, we report 3,5-dithienyl Aza-BODIPYs with a donor-acceptor-donor (D-A-D) architecture as the first charge transfer (CT)-coupled J-aggregation BODIPY-type platform. The core acceptor moieties in one molecule interact with donor units in neighboring molecules to generate slip-stacked packing motifs, resulting in CT-coupled J-aggregation with a redshifted wavelength up to 886 nm and an absorption tail over 1100 nm. The J-aggregates show significant photoacoustic signals and high photothermal conversion efficiency of 66%. The results obtained in vivo show that the J-aggregates have the potential to be used for tumor photothermal ablation and photoacoustic imaging. This study not only demonstrates Aza-BODIPY with D-A-D as a novel CT-coupled J-aggregation platform for NIR phototherapy materials but also motivates further study on the design of J-aggregation.

Hydraulic Expansion Joint Contact State of Heat Exchanger Based on New Contact Area Measurement Method.

The contact state of a seamless internal threaded copper tube and an aluminium foil fin not only affects the heat transfer efficiency of a tube-fin heat exchanger but also seriously affects its service life. In this study, hydraulic expansion technology was used to connect the copper tube with an internal thread with a 7 mm diameter to the fin of the heat exchanger. The influence of the expansion pressure and pressure holding time on the contact state was analysed through experiments and finite element simulation, and the variation law of the two on the contact state was obtained. The contact state was characterised by the contact gap and contact area. In order to obtain the specific contact area value, a new method of measuring the contact area was developed to reveal the variation in contact area between the copper tube and the fin after expansion. The results show that the contact gap decreases with an increase in expansion pressure, while the pressure holding time remains the same. The contact area increases with an increase in expansion pressure, and the rate of increase slows. When the expansion pressure is 18 MPa, the average contact gap is approximately 0.018 mm. When the expansion pressure reaches 16 MPa, the contact area ratio is 91.0%. When the expansion pressure increases to 18 MPa, the contact area ratio only increases by approximately 0.6%. Compared with the influence of the expansion pressure on the increase in contact area, the influence of the pressure holding time on the contact area is lower.

Novel organoboron complexes with robust core: Synthesis, functionalization, and subcellular targeting.

The construction of novel organoboron complexes with facile synthesis and unique advantages for biological imaging remains a challenge and thus has garnered considerable attention. Herein, we developed a new molecular platform, boron indolin-3-one-pyrrol (BOIN3OPY) via a two-step sequential reaction. The molecular core is robust enough to allow for post-functionalization to produce versatile dyes. When compared to the standard BODIPY, these dyes feature an N,O-bidentate seven-membered ring center, significantly redshifted absorption, and a larger Stokes shift. This study establishes a new molecular platform that provides more flexibility for the functional regulation of dyes.

H2S-mediated balance regulation of stomatal and non-stomatal factors responding to drought stress in Chinese cabbage.

Increased evidence has shown that hydrogen sulfide (H2S), a novel gasotransmitter, could enhance drought resistance in plants by inducing stomatal closure, with concurrent enhancement of photosynthetic efficiency, but little is known about the mechanism behind this contradictory phenomenon. This study examined the regulating mechanism of H2S in response to drought stress from stomatal and non-stomatal factors in Chinese cabbage. The results showed that exogenous H2S could increase the accumulation of photosynthetic pigments and alleviate the damage caused by drought stress. It also regulated the expression in transcriptional level and the activity of ribulose 1,5-bisphosphate carboxylase/oxygenase (BrRuBisCO) under drought stress. The large subunit of BrRuBisCO was found to be modified by S-sulfhydration, which might be the reason for its increased enzyme activity. The fluxes of Cl-, K+, and H+ in the guard cells were detected by non-invasive micro-test techniques while under drought stress. The results indicated that H2S signaling induced a transmembrane Cl- and H+ efflux and inhibited K+ influx, and the Cl- channel was the main responders for H2S-regulated stomatal movement. In conclusion, H2S signal not only activated the ion channel proteins located in the guard cell membrane to induce stomatal closure, but also regulated the transcriptional expression and the activity of RuBisCO, a non-stomatal factor to enhance the photosynthetic efficiency of leaves. There is therefore a beneficial balance between the regulation of H2S signaling on stomatal factors and non-stomatal factors due to drought stress, which needs to be better understood to apply it practically to increase crop yields.

Response of Juvenile Saccharina japonica to the Combined Stressors of Elevated pCO2 and Excess Copper.

Coastal macroalgae may be subjected to global and local environmental stressors, such as ocean acidification and heavy-metal pollution. We investigated the growth, photosynthetic characteristics, and biochemical compositions of juvenile sporophytes of Saccharina japonica cultivated at two pCO2 levels (400 and 1000 ppmv) and four copper concentrations (natural seawater, control; 0.2 µM, low level; 0.5 µM, medium level; and 1 µM, high level) to better understand how macroalgae respond to ongoing environmental changes. The results showed that the responses of juvenile S. japonica to copper concentrations depended on the pCO2 level. Under the 400 ppmv condition, medium and high copper concentrations significantly decreased the relative growth rate (RGR) and non-photochemical quenching (NPQ) but increased the relative electron transfer rate (rETR) and chlorophyll a (Chl a), chlorophyll c (Chl c), carotenoid (Car), and soluble carbohydrate contents. At 1000 ppmv, however, none of the parameters had significant differences between the different copper concentrations. Our data suggest that excess copper may inhibit the growth of juvenile sporophytes of S. japonica, but this negative effect could be alleviated by CO2-induced ocean acidification.

Fixing sulfur dioxide by feeding calcine oxide into the rotary volatilization kiln in zinc smelting plant.

Sulfur dioxide (SO2) is a toxic pollutant and its fixation is a high cost but imperative task for sulfide metallurgy industry. Although being a mature technology for on-line fixation of SO2 by limestone injection in coal-fired boilers, its application is rarely investigated in the sulfide metallurgy plant. Extending this technology to the metallurgy industry is highly plausible, but with the feasibility and practicability waiting to be uncovered. Herein, feeding CaO into the rotary volatilization kiln as SO2-fixation agent is demonstrated to be an efficient in-furnace desulfurization strategy for zinc smelting plant. The sulfur distribution within the entire smelting process is systematically analyzed, determining that the critical procedure for pressuring the desulfurization system is the rotary volatilization kiln. The thermodynamics analysis shows that addition of CaO is feasible for SO2 fixation by forming CaS or restraining the reductive decomposition of SO42-. The industrial tests, including the online monitoring of kiln flue gas and kiln slag analysis, validate the thermodynamics analysis, realizing a 24.6% reduction of SO2 in the flue gas by converting gaseous SO2 to solid CaS via feeding 20% CaO. The present study highlights an effective strategy for on-line fixing the SO2, being a potential way for relieving the desulfurization pressures in zinc sulfide metallurgy plant.

Decreased Salinity Offsets the Stimulation of Elevated pCO2 on Photosynthesis and Synergistically Inhibits the Growth of Juvenile Sporophyte of Saccharina japonica (Laminariaceae, Phaeophyta).

The combined effect of elevated pCO2 (Partial Pressure of Carbon Dioxide) and decreased salinity, which is mainly caused by freshwater input, on the growth and physiological traits of algae has been poorly assessed. In order to investigate their individual and interactive effects on the development of commercially farmed algae, the juvenile sporophytes of Saccharina japonica were cultivated under different levels of salinity (30, 25 and 20 psu) and pCO2 (400 and 1000 µatm). Individually, decreased salinity significantly reduced the growth rate and pigments of S. japonica, indicating that the alga was low-salinity stressed. The maximum quantum yield, Fv/Fm, declined at low salinities independent of pCO2, suggesting that the hyposalinity showed the main effect. Unexpectedly, the higher pCO2 enhanced the maximum relative electron transport rate (rETRmax) but decreased the growth rate, pigments and soluble carbohydrates contents. This implies a decoupling between the photosynthesis and growth of this alga, which may be linked to an energetic reallocation among the different metabolic processes. Interactively and previously untested, the decreased salinity offset the improvement of rETRmax and aggravated the declines of growth rate and pigment content caused by the elevated pCO2. These behaviors could be associated with the additionally decreased pH that was induced by the low salinity. Our data, therefore, unveils that the decreased salinity may increase the risks of future CO2-induced ocean acidification on the production of S. japonica.

Neopetrosins A-D and Haliclorensin D, Indole-C-Mannopyranosides and a Diamine Alkaloid Isolated from the South China Sea Marine Sponge Neopetrosia chaliniformis.

Four new indole-C-mannopyranoside alkaloids, neopetrosins A-D (1-4), together with one new diamine alkaloid, haliclorensin D (6), were isolated from the marine sponge Neopetrosia chaliniformis collected off Xisha Island in the South China Sea. Their structures and absolute configurations were determined by spectroscopic analysis, single-crystal X-ray diffraction, calculated electronic circular dichroism (ECD), and DP4+ probability analyses. Compounds 1, 2, and 4 exhibited in vivo hepatoprotective activity in a zebrafish model at a concentration of 20 µM.

Evaluation of Shear and Peel Strength of Al1060 Single-Lap and T-Lap Joints Produced by Rotated Clinching Process with Twin Rotating Punches.

The clinching process is widely used in joining lightweight sheet metal. We proposed a novel rotated clinching process (RCP), which is characterized by a flat bottom die structure and twin rotating punches. The aim of this study was to evaluate the strength of RCP joints. Al1060 sheets with thicknesses of 1.5 mm and 2 mm were used as the experimental materials. Overlap and T-lap RCP joints with three die depths and five bottom thicknesses were fabricated, and shear and peel tests were performed on the joints. The joint strengths were evaluated based on the mechanical load, cross-sectional profile dimensions, and failure mode. The results showed that the mechanical load is a direct, reliable, and quantitative evaluation criterion, while the cross-sectional profile and failure mode are indirect and qualitative. These criteria confirmed that the strength of thick sheet joints is higher than that of thin sheet joints, the shear strength is superior to the peel strength, and the strengths of the joints are high with failure mainly occurring due to tearing or shear failure. Finally, the key parameters for determining the strength of a joint include the bottom thickness/sheet thickness ratio (Rt), and the die depth (h).

Four bioactive new steroids from the soft coral Lobophytum pauciflorum collected in South China Sea.

Four new polyhydroxylated steroids lobophysterols E-H (1-4), together with three known compounds (5-7), were isolated from the soft coral Lobophytum pauciflorum collected at Xisha Island, China. The structures of the new compounds were elucidated by extensive spectroscopic analysis and comparison with NMR data of structurally related compounds reported in the literature. The absolute configuration of 1-3 was determined by X-ray diffraction. All the compounds have assessed the cytotoxicity against HL-60, K562, and Hela cells. Compound 1 showed weak cytotoxicity against K562 cells with an IC50 value of 19.03 µM. In addition, compound 1 also showed a moderate anti-inflammatory effect in zebrafish.

Renal-clearable and biodegradable black phosphorus quantum dots for photoacoustic imaging of kidney dysfunction.

The kidney is a vital organ and susceptible to various diseases. Photoacoustic (PA) imaging provides a powerful technique for studying kidney dysfunction, for which many smart photoacoustic imaging agents have been developed. But the complete clearance of the introduced contrast agents after imaging remains to be challenging, leading to long-term toxicity concerns. In this study, we synthesized black phosphorous quantum dots (BPQDs) with ultra-small size (1.74 ± 0.23 nm after surface modification) and strong PA signal for imaging kidney dysfunction. Importantly, the renal-clearance property and biodegradability of the developed BPQDs help circumvent the long-term toxicity issue for in vivo studies. Based on these BPQDs, both acute kidney injury and chronic kidney disease were successfully detected in the living mice by PA imaging, with higher detection sensitivity than the clinical serum indices examination method. This BPQDs-based PA imaging method should have a promising potential for the early diagnosis of kidney dysfunction in clinic.

Novel single-armed nitrogen-heterocyclic salamo-based fluorescent sensors for the detection of Al3+ and CN.

Two novel single-armed nitrogen-heterocyclic chemosensors with basically similar structures, PDNS and PZNS, were synthesized to specifically identify Al3+ in DMS:H2O (1:1 v/v) solution by fluorescence emission spectroscopy, and the colour of PDNS and PZNS changed from yellow to colorless when Al3+ was added under daylight. This is the first time that nitrogen-heterocyclic is introduced into salamo-based chemical sensor. At excitation wavelengths of 361 and 365 nm, solutions of PDNS and PZNS changed to intense green-blue fluorescence. Furthermore, it was found that PDNS/PZNS and Al3+ have excellent binding capacity, the lower limit of detection (LOD = 6.25 × 10-9/1.26 × 10-9 mol·dm-3) is also calculated. In addition, sensor PZNS can detect Al3+ in a solution system with up to 95% water content and applicable pH range is 3-12. Compared to other salamo-based sensors, PZNS and PDNS have broader detection conditions and wider utilities. PZNS can also identify CN- in fluorescence spectrum. PZNS can be used for detection of Al3+ in aqueous systems in daily production and life.

Auxin is involved in arbuscular mycorrhizal fungi-promoted tomato growth and NADP-malic enzymes expression in continuous cropping substrates.

BACKGROUND: Despite significant limitations of growth medium reuse, a large amount of organic substrate is reused in soilless cultivation of horticultural crops in China. Arbuscular mycorrhizal fungi (AMF) can promote nutrient absorption and improve plant tolerance to biotic and abiotic stresses. However, the mechanisms governing the effects of AMF on crop growth in organic continuous cropping substrates have not been elucidated. RESULTS: In this study, we showed that the inoculation of AMF in continuous cropping substrates promoted growth and root development, and increased the root and NADP-malic enzyme (NADP-ME) activity of tomato seedlings. Root transcriptome analysis demonstrated that the plant hormone signal transduction pathway was highly enriched, and 109 genes that positively correlated with the AMF-inoculated plant phenotype were obtained by gene set enrichment analysis (GSEA), which identified 9 genes related to indole acetic acid (IAA). Importantly, the levels of endogenous IAA in tomato seedlings significantly increased after AMF inoculation. Furthermore, the application of AMF significantly increased the expression levels of NADP-ME1 and NADP-ME2, as well as the activity of NADP-ME, and enhanced the root activity of tomato seedlings in comparison to that observed without inoculation of AMF. However, these effects were blocked in plants treated with 2,3,5-triiodobenzoic acid (TIBA), a polar transport inhibitor of IAA. CONCLUSIONS: These results suggest that IAA mediates the AMF-promoted tomato growth and expression of NADP-MEs in continuous cropping substrates. The study provides convincing evidence for the reuse of continuous cropping substrates by adding AMF as an amendment.