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Scientific Reports Jun 2024Investigating differences in resistance to alkaline stress among three willow species can provide a theoretical basis for planting willow in saline soils. Therefore we...
Investigating differences in resistance to alkaline stress among three willow species can provide a theoretical basis for planting willow in saline soils. Therefore we tested three willow species (Salix matsudana, Salix gordejevii and Salix linearistipularis), already known for their high stress tolerance, to alkaline stress environment at different pH values under hydroponics. Root and leaf dry weight, root water content, leaf water content, chlorophyll content, photosynthesis and chlorophyll fluorescence of three willow cuttings were monitored six times over 15 days under alkaline stress. With the increase in alkaline stress, the water retention capacity of leaves of the three species of willow cuttings was as follows: S. matsudana > S. gordejevii > S. linearistipularis and the water retention capacity of the root system was as follows: S. gordejevii > S. linearistipularis > S. matsudana. The chlorophyll content was significantly reduced, damage symptoms were apparent. The net photosynthetic rate (Pn), rate of transpiration (E), and stomatal conductance (Gs) of the leaves showed a general trend of decreasing, and the intercellular CO concentration (Ci) of S. matsudana and S. gordejevii first declined and then tended to level off, while the intercellular CO concentration of S. linearistipularis first declined and then increased. The quantum yield and energy allocation ratio of the leaf photosystem II (PSII) reaction centre changed significantly (φPo, Ψo and φEo were obviously suppressed and φDo was promoted). The photosystem II (PSII) reaction centre quantum performance index and driving force showed a clear downwards trend. Based on the results it can be concluded that alkaline stress tolerance of three willow was as follows: S. matsudana > S. gordejevii > S. linearistipularis. However, since the experiment was done on young seedlings, further study at saplings stage is required to revalidate the results.
Topics: Photosynthesis; Salix; Chlorophyll; Stress, Physiological; Plant Leaves; Plant Roots; Hydrogen-Ion Concentration; Water; Plant Transpiration
PubMed: 38918471
DOI: 10.1038/s41598-024-65004-5 -
Plant Signaling & Behavior Dec 2024MYB transcription factor is one of the largest families in plants. There are more and more studies on plants responding to abiotic stress through MYB transcription...
MYB transcription factor is one of the largest families in plants. There are more and more studies on plants responding to abiotic stress through MYB transcription factors, but the mechanism of some family members responding to salt stress is unclear. In this study, physiological and transcriptome techniques were used to analyze the effects of the R2R3-MYB transcription factor on the growth and development, physiological function, and key gene response of . Phenotypic observation showed that the damage of overexpression strain was more serious than that of Col-0 after salt treatment, while the mutant strain showed less salt injury symptoms. Under salt stress, the decrease of chlorophyll content, the degree of photoinhibition of photosystem II (PSII) and photosystem I (PSI) and the degree of oxidative damage of overexpressed lines were significantly higher than those of Col-0. Transcriptome data showed that the number of differentially expressed genes (DEGs) induced by salt stress in overexpressed lines was significantly higher than that in Col-0. GO enrichment analysis showed that the response of to salt stress was mainly by affecting gene expression in cell wall ectoplast, photosystem I and photosystem II, and other biological processes related to photosynthesis. Compared with Col-0, the overexpression of under salt stress further inhibited the synthesis of chlorophyll a (Chla) and down-regulated most of the genes related to photosynthesis, which made the photosynthetic system more sensitive to salt stress. also caused the outbreak of reactive oxygen species and the accumulation of malondialdehyde under salt stress, which decreased the activity and gene expression of key enzymes in SOD, POD, and AsA-GSH cycle, thus destroying the ability of antioxidant system to maintain redox balance. negatively regulates the accumulation of osmotic regulatory substances such as soluble sugar (SS) and soluble protein (SP) in leaves under salt stress, which enhances the sensitivity of Arabidopsis leaves to salt. To sum up, negatively regulates the salt tolerance of by destroying the light energy capture, electron transport, and antioxidant capacity of Arabidopsis.
Topics: Arabidopsis; Photosynthesis; Plant Leaves; Arabidopsis Proteins; Salt Stress; Oxidative Stress; Gene Expression Regulation, Plant; Transcription Factors; Photosystem II Protein Complex; Photosystem I Protein Complex; Chlorophyll
PubMed: 38916149
DOI: 10.1080/15592324.2024.2371694 -
Oncoimmunology 2024Regulatory T cells (Tregs) play a crucial role in mediating immunosuppression in the tumor microenvironment. Furthermore, Tregs contribute to the lack of efficacy and...
Regulatory T cells (Tregs) play a crucial role in mediating immunosuppression in the tumor microenvironment. Furthermore, Tregs contribute to the lack of efficacy and hyperprogressive disease upon Programmed cell death protein 1 (PD-1) blockade immunotherapy. Thus, Tregs are considered a promising therapeutic target, especially when combined with PD-1 blockade. However, systemic depletion of Tregs causes severe autoimmune adverse events, which poses a serious challenge to Treg-directed therapy. Here, we developed a novel treatment to locally and predominantly damage Tregs by near-infrared duocarmycin photorelease (NIR-DPR). In this technology, we prepared anti-CD25 F(ab') conjugates, which site-specifically uncage duocarmycin in CD25-expressing cells upon exposure to NIR light. , CD25-targeted NIR-DPR significantly increased apoptosis of CD25-expressing HT2-A5E cells. When tumors were irradiated with NIR light , intratumoral CD25 Treg populations decreased and Ki-67 and Interleukin-10 expression was suppressed, indicating impaired functioning of intratumoral CD25 Tregs. CD25-targeted NIR-DPR suppressed tumor growth and improved survival in syngeneic murine tumor models. Of note, CD25-targeted NIR-DPR synergistically enhanced the efficacy of PD-1 blockade, especially in tumors with higher CD8/Treg PD-1 ratios. Furthermore, the combination therapy induced significant anti-cancer immunity including maturation of dendritic cells, extensive intratumoral infiltration of cytotoxic CD8 T cells, and increased differentiation into CD8 memory T cells. Altogether, CD25-targeted NIR-DPR locally and predominantly targets Tregs in the tumor microenvironment and synergistically improves the efficacy of PD-1 blockade, suggesting that this combination therapy can be a rational anti-cancer combination immunotherapy.
Topics: Animals; T-Lymphocytes, Regulatory; Mice; Programmed Cell Death 1 Receptor; Tumor Microenvironment; Duocarmycins; Immunoconjugates; Humans; Cell Line, Tumor; Female; Interleukin-2 Receptor alpha Subunit; Immune Checkpoint Inhibitors; Disease Models, Animal; Mice, Inbred C57BL; Apoptosis; Infrared Rays
PubMed: 38915782
DOI: 10.1080/2162402X.2024.2370544 -
Scientific Reports Jun 2024Flavonoids are crucial secondary metabolites that possess the ability to mitigate UV damage and withstand both biotic and abiotic stresses. Therefore, it is of immense...
Flavonoids are crucial secondary metabolites that possess the ability to mitigate UV damage and withstand both biotic and abiotic stresses. Therefore, it is of immense significance to investigate the flavonoid content as a pivotal indicator for a comprehensive assessment of chestnut's drought tolerance. This study aimed to determine the flavonoid content and drought tolerance-related physiological and biochemical indices of six chestnut varieties (clones) grafted trees-Qianxi 42 (QX42), Qinglong 45 (QL45), Yanshanzaofeng (YSZF), Yanzi (YZ), Yanqiu (YQ), and Yanlong (YL)-under natural drought stress. The results were used to comprehensively analyze the drought tolerance ability of these varieties. The study revealed that the ranking of drought tolerance indices in terms of their ability to reflect drought tolerance was as follows: superoxide (oxide) dismutase (SOD) activity, ascorbate peroxidase (APX) activity, flavone content, catalase (CAT) activity, proline (PRO) content, soluble sugar content, peroxidase (POD) activity, betaine content, flavonol content, hydrogen peroxide (HO) content, soluble protein content, superoxide ion (OFR) content, superoxide (ion OFR) production rate, malondialdehyde (MDA) content, chlorophyll content. Through principal component analysis, the contents of flavonoids and flavonols can be used as indicators for comprehensive evaluation of drought tolerance of chestnut. The comprehensive evaluation order of drought tolerance of grafted trees of 6 chestnut varieties (Clones) was: QL45 > QX42 > YQ > YZ > YSZF > YL.
Topics: Flavonoids; Droughts; Stress, Physiological; Malondialdehyde; Superoxide Dismutase; Proline; Chlorophyll; Hydrogen Peroxide; Fagaceae; Adaptation, Physiological; Catalase; Ascorbate Peroxidases; Drought Resistance; East Asian People
PubMed: 38914646
DOI: 10.1038/s41598-024-65479-2 -
The Journal of Chemical Physics Jun 2024The microwave spectrum of 2,4-dimethylpyrrole was investigated using a Fourier-transform microwave spectrometer in a supersonic expansion. Torsional splittings arising...
The microwave spectrum of 2,4-dimethylpyrrole was investigated using a Fourier-transform microwave spectrometer in a supersonic expansion. Torsional splittings arising from two inequivalent methyl internal rotors in combination with hyperfine splittings due to the nuclear quadrupole coupling of the 14N nucleus were observed. The experiments were accompanied by quantum chemical calculations. A total of 1561 rotational lines were assigned and fitted in global fits using the programs XIAM and BELGI-Cs-2Tops-hyperfine, both achieved the measurement accuracy of 4 kHz. Local separate fits were also performed to verify the correctness of the assignment. Accurate experimental molecular and internal rotation parameters could be deduced and compared to the calculated ones. The barrier to internal rotation of the 2-methyl rotor was determined to be 277.830(26) cm-1, essentially the same as the value of about 280 cm-1 found for 2-methylpyrrole but lower than the value of 317 cm-1 found for 2,5-dimethylpyrrole. The torsional barrier value of the 4-methyl rotor is 262.210(27) cm-1, slightly higher than the value of 246 cm-1 found for 3-methylpyrrole. Benchmarking the rotational constants for 2,4- and 2,5-dimethylpyrrole revealed that the MP2/6-31G(d,p) level could be helpful to guide the assignment of microwave spectra of pyrrole derivatives.
PubMed: 38912676
DOI: 10.1063/5.0213319 -
Environmental Research Jun 2024In this study, g-CN/PANI was prepared by in situ oxidative polymerization. Graphite-phase carbon nitride (g-CN) with surface defects was deposited onto the surface of...
In this study, g-CN/PANI was prepared by in situ oxidative polymerization. Graphite-phase carbon nitride (g-CN) with surface defects was deposited onto the surface of conductive polyaniline (PANI) to form a p-n heterojunction. This construction aimed to create an efficient heterogeneous catalyst, increasing the surface defect level and active sites of the composite, and augmenting its capability to capture and transfer extracellular electrons under anaerobic conditions. This addresses the challenge of low efficiency in direct interspecies electron transfer between bacteria and archaea during anaerobic digestion for methane production. The results showed that the prepared g-CN/PANI increased the CH yield and CH production rate by 82% and 96%, respectively. Notably, the conductivity and XPS test results showed that the ratio of g-CN to PANI was 0.15, and the composite exhibited favorable conductivity, with a uniform distribution of pyrrolic nitrogen, pyridinic nitrogen, and graphitic nitrogen, each accounting for approximately 30%. Furthermore, g-CN/PANI effectively enhanced the metabolic efficiency of intermediate products such as acetate and butyrate. Analysis of the microbial community structure revealed that g-CN/PANI led to a significant increase in the abundance of hydrogenotrophic methanogen Methanolinea (from 48% to 64%) and enriched Clostridium (a rise of 1%) with direct interspecies electron transfer capability. Microbial community function analysis demonstrated that the addition of g-CN/PANI boosted the activities of key enzymes involved in anaerobic digestion, including phosphate transacetylase (PTA), phospho-butyryl transferase (PTB), and NAD-independent lactate dehydrogenase (NNLD), by 47%, 135%, and 153%, respectively. This acceleration in enzymatic activity promoted the metabolism of acetyl-CoA, butyryl-CoA, and pyruvate. Additionally, the function of ABC transporters was enhanced, thereby improving the efficiency of material and energy exchange among microorganisms.
PubMed: 38909948
DOI: 10.1016/j.envres.2024.119480 -
Biosensors & Bioelectronics Oct 2024An electrochemical (EC) sensor based on metalloporphyrin metal-organic framework (MOF) for the detection of parathion-methyl (PM) has been developed. The prepared...
An electrochemical (EC) sensor based on metalloporphyrin metal-organic framework (MOF) for the detection of parathion-methyl (PM) has been developed. The prepared MOF-525(Fe) exhibits great signal enhancement toward the electrochemical detection of PM owing to its unique structural properties and electrochemical activities. Under optimal experimental conditions, the as-prepared MOF-525(Fe) based EC sensor exhibited excellent PM sensing performance with a wide linear detection range (0.1 μM-100 μM) and low limit of detection (LOD, 1.4 nM). Compared to its corresponding Fe metalloporphyrin (linker), MOF-525(Fe) exhibited a superior sensitivity (28.31 μA cm·μM), which is 3.7 times higher than the sensitivity of FeTCPP linker (7.56 μA cm·μM) towards PM. The improved performance is associated with the high specific surface area and the large pore channels of MOF-525(Fe) facilitating a better interaction between PM and the Fe metalloporphyrin active sites, especially in the lower concentration range. Moreover, a possible affinity of the PM molecules toward Zr clusters may also contribute to the selective enrichment of PM on MOF-525(Fe). This EC sensor further demonstrated high selectivity in the presence of interfering molecules. The recovery results further confirm accurate PM sensing in actual samples, which suggests promising applications for the rapid detection of environmental organophosphates by metalloporphyrin MOFs.
Topics: Metal-Organic Frameworks; Electrochemical Techniques; Biosensing Techniques; Metalloporphyrins; Limit of Detection; Zirconium; Methyl Parathion
PubMed: 38909444
DOI: 10.1016/j.bios.2024.116515 -
Journal of Nanobiotechnology Jun 2024Hypoxia-activated prodrug (HAP) is a promising candidate for highly tumor-specific chemotherapy. However, the oxygenation heterogeneity and dense extracellular matrix...
BACKGROUND
Hypoxia-activated prodrug (HAP) is a promising candidate for highly tumor-specific chemotherapy. However, the oxygenation heterogeneity and dense extracellular matrix (ECM) of tumor, as well as the potential resistance to chemotherapy, have severely impeded the resulting overall efficacy of HAP.
RESULTS
A HAP potentiating strategy is proposed based on ultrasound responsive nanodroplets (PTP@PLGA), which is composed of protoporphyrin (PpIX), perfluoropropane (PFP) and a typical HAP, tirapazamine (TPZ). The intense vaporization of PFP upon ultrasound irradiation can magnify the sonomechanical effect, which loosens the ECM to promote the penetration of TPZ into the deep hypoxic region. Meanwhile, the PpIX enabled sonodynamic effect can further reduce the oxygen level, thus activating the TPZ in the relatively normoxic region as well. Surprisingly, abovementioned ultrasound effect also results in the downregulation of the stemness of cancer cells, which is highly associated with drug-refractoriness.
CONCLUSIONS
This work manifests an ideal example of ultrasound-based nanotechnology for potentiating HAP and also reveals the potential acoustic effect of intervening cancer stem-like cells.
Topics: Humans; Tirapazamine; Protoporphyrins; Fluorocarbons; Prodrugs; Cell Line, Tumor; Nanoparticles; Neoplastic Stem Cells; Antineoplastic Agents; Ultrasonic Waves; Animals; Extracellular Matrix; Mice; Neoplasms
PubMed: 38907270
DOI: 10.1186/s12951-024-02623-0 -
BMC Plant Biology Jun 2024Drought stress poses a significant threat to agricultural productivity, especially in areas susceptible to water scarcity. Sunflower (Helianthus annuus L.) is a widely...
Mitigation of drought-induced stress in sunflower (Helianthus annuus L.) via foliar application of Jasmonic acid through the augmentation of growth, physiological, and biochemical attributes.
Drought stress poses a significant threat to agricultural productivity, especially in areas susceptible to water scarcity. Sunflower (Helianthus annuus L.) is a widely cultivated oilseed crop with considerable potential globally. Jasmonic acid, a plant growth regulator, plays a crucial role in alleviating the adverse impacts of drought stress on the morphological, biochemical, and physiological characteristics of crops. Experimental detail includes sunflower varieties (Armani Gold, KQS-HSF-1, Parsun, and ESFH-3391), four drought stress levels (0, 25%, 50%, and 75% drought stress), and three levels (0, 40ppm, 80ppm) of jasmonic acid. The 0% drought stress and 0ppm jasmonic acid were considered as control treatments. The experimental design was a completely randomized design with three replicates. Drought stress significantly reduced the growth in all varieties. However, the exogenous application of jasmonic acid at concentrations of 40ppm and 80ppm enhanced growth parameters, shoot and root length (1.93%, 19%), shoot and root fresh weight (18.5%, 25%), chlorophyll content (36%), photosynthetic rate (22%), transpiration rate (40%), WUE (20%), MDA (6.5%), Phenolics (19%), hydrogen peroxide (7%) proline (28%) and glycine betaine (15-30%) under water-stressed conditions, which was closely linked to the increase in stomatal activity stimulated by jasmonic acid. Furthermore, JA 80 ppm was found to be the most appropriate dose to reduce the effect of water stress in all sunflower varieties. It was concluded that the foliar application of JA has the potential to enhance drought tolerance by improving the morphological, biochemical, and physiological of sunflower.
Topics: Oxylipins; Cyclopentanes; Helianthus; Droughts; Plant Growth Regulators; Stress, Physiological; Plant Leaves; Photosynthesis; Chlorophyll
PubMed: 38907232
DOI: 10.1186/s12870-024-05273-4 -
Bioorganic & Medicinal Chemistry Jul 2024The antimicrobial activity of new acid-functionalized porphyrins, with or without ultra-high irradiance, was investigated. Antibacterial efficacy was evaluated against...
Synthesis and characterization of new acid-functionalized porphyrins displaying antimicrobial activity against gram positive bacteria, yeasts and filamentous fungi with or without ultra-high irradiance.
The antimicrobial activity of new acid-functionalized porphyrins, with or without ultra-high irradiance, was investigated. Antibacterial efficacy was evaluated against Staphylococcus aureus (methicillin-resistant or methicillin-sensitive strains) and antifungal efficacy was evaluated against the yeast Candida albicans and the filamentous fungi Aspergillus fumigatus. Overall, the porphyrins tested are more effective against S. aureus. The best results were obtained with zinc diacid porphyrins 4 and 5 after only 3 min of ultra-high irradiation (500 mW/cm, 405 nm), demonstrating that acid-functionalized porphyrins are promising as novel antimicrobial drugs for surface disinfection.
Topics: Microbial Sensitivity Tests; Porphyrins; Aspergillus fumigatus; Candida albicans; Antifungal Agents; Anti-Bacterial Agents; Gram-Positive Bacteria; Staphylococcus aureus; Structure-Activity Relationship; Molecular Structure; Dose-Response Relationship, Drug; Fungi
PubMed: 38906069
DOI: 10.1016/j.bmc.2024.117810