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The Journal of Organic Chemistry Jun 2023Chiral Ni complexes have revolutionized both asymmetric acid-base and redox catalysis. However, the coordination isomerism of Ni complexes and their open-shell property...
Chiral Ni complexes have revolutionized both asymmetric acid-base and redox catalysis. However, the coordination isomerism of Ni complexes and their open-shell property still often hinder the elucidation of the origin of their observed stereoselectivity. Here, we report our experimental and computational investigations to clarify the mechanism of β-nitrostyrene facial selectivity switching in Ni(II)-diamine-(OAc)-catalyzed asymmetric Michael reactions. In the reaction with a dimethyl malonate, the Evans transition state (TS), in which the enolate binds in the same plane with the diamine ligand, is identified as the lowest-energy TS to promote C-C bond formation from the face in β-nitrostyrene. In contrast, a detailed survey of the multiple potential pathways in the reaction with α-keto esters points to a clear preference for our proposed C-C bond-forming TS, in which the enolate coordinates to the Ni(II) center in apical-equatorial positions relative to the diamine ligand, thereby promoting face addition in β-nitrostyrene. The N-H group plays a key orientational role in minimizing steric repulsion.
Topics: Nickel; Diamines; Ligands; Carboxylic Acids; Catalysis
PubMed: 36813263
DOI: 10.1021/acs.joc.2c02732 -
International Journal of Molecular... Aug 2022Deficiency or excess of iron (Fe) and improper medium pH will inhibit the growth and development of plants, reduce the transfer and utilization of energy from the root...
Deficiency or excess of iron (Fe) and improper medium pH will inhibit the growth and development of plants, reduce the transfer and utilization of energy from the root to the leaf, and affect the utilization efficiency of inorganic nutrients. The most common symptom of Fe deficiency in plants is chlorosis of the young leaves. In this study, the effects of the iron source, in combination with the medium pH, on plant growth and development, plant pigment synthesis, and nutrient uptake in a model plant cultured in vitro were investigated. Iron sulfate (FeSO·7HO) or iron chelated with ethylenediaminetetraacetic acid (Fe-EDTA) were supplemented to the MNS (a multipurpose nutrient solution) medium at a concentration of 2.78 mg·L Fe, and the treatment without any Fe was used as the control. The pH of the agar-solidified medium was adjusted to either 4.70, 5.70, or 6.70 before autoclaving. The experiment was carried out in an environmentally controlled culture room with a temperature of 24 °C with 100 µmol·m·s photosynthetic photon flux density (PPFD) supplied by white light emitting diodes (LEDs) during a photoperiod of 16 h a day, 18 °C for 8 h a day in the dark, and 70% relative humidity. Regardless of the Fe source including the control, the greatest number of leaves was observed at pH 4.70. However, the greatest lengths of the leaf and root were observed in the treatment with Fe-EDTA combined with pH 5.70. The contents of the chlorophyll, carotenoid, and anthocyanin decreased with increasing medium pH, and contents of these plant pigments were positively correlated with the leaf color. The highest soluble protein content and activities of APX and CAT were observed in the Fe-EDTA under pH 5.70. However, the GPX activity was the highest in the control under pH 4.70. In addition, the highest contents of ammonium (NH) and nitrate (NO) were measured in the FeSO-4.7 and EDTA-5.7, respectively. More than that, the treatment of Fe-EDTA combined with pH 5.70 (EDTA-5.7) enhanced nutrient absorption, as proven by the highest tissue contents of P, K, Ca, Mg, Fe, and Mn. The genes' ferric reduction oxidase 1 and 8 ( and ), iron-regulated transporter 1 (), nitrate transporter 2.5 (), and deoxyhypusine synthase () were expressed at the highest levels in this treatment as well. In the treatment of EDTA-5.7, the reduction and transport of chelated iron in leaves were enhanced, which also affected the transport of nitrate and catalyzed chlorophyll level in leaves. In conclusion, when the medium pH was adjusted to 5.70, supplementation of chelated Fe-EDTA was more conducive to promoting the growth and development of, and absorption of mineral nutrients by, the plant and the expression of related genes in the leaves.
Topics: Chlorophyll; Edetic Acid; Hydrogen-Ion Concentration; Iron; Nitrates; Nutrients; Petunia; Plant Leaves; Plant Roots
PubMed: 36012209
DOI: 10.3390/ijms23168943 -
Molecular Vision 2022Tissue engineering of the corneal endothelium, as well as cell therapy, has been proposed as an alternative approach for the treatment of corneal endotheliopathies....
PURPOSE
Tissue engineering of the corneal endothelium, as well as cell therapy, has been proposed as an alternative approach for the treatment of corneal endotheliopathies. These approaches require in vitro amplification of functional corneal endothelial cells (CECs). The goal of this study was to compare two common isolation methods, collagenase A and EDTA (EDTA), and determine whether they influence cell viability, morphology, and barrier function.
METHODS
Human eye bank research-grade corneas were used to isolate and cultivate CECs. All donors were more than 40 years old. Two Descemet membranes from the same donor were used separately to compare the collagenase A and EDTA cell isolation methods. The number of isolated cells, cell viability, morphology, and barrier functionality were compared.
RESULTS
A higher isolation efficiency of viable CECs and a higher circularity index (endothelial morphology) were obtained using collagenase A. Passage 3 cells presented similar barrier functionalities regardless of the isolation method.
CONCLUSIONS
This study showed that isolation of CECs using collagenase A yields higher isolation efficiency than EDTA, delaying the loss of endothelial morphology for early passage cells.
Topics: Humans; Adult; Edetic Acid; Endothelial Cells; Endothelium, Corneal; Cell Separation; Collagenases
PubMed: 36338664
DOI: No ID Found -
AJNR. American Journal of Neuroradiology Aug 2019The manganese ion is used as an intracellular MR imaging contrast agent to study neuronal function in animal models, but it remains unclear whether manganese-enhanced MR...
BACKGROUND AND PURPOSE
The manganese ion is used as an intracellular MR imaging contrast agent to study neuronal function in animal models, but it remains unclear whether manganese-enhanced MR imaging can be similarly useful in humans. Using mangafodipir (Teslascan, a chelated manganese-based contrast agent that is FDA-approved), we evaluated the dynamics of manganese enhancement of the brain and glandular structures in the rostral head and neck in healthy volunteers.
MATERIALS AND METHODS
We administered mangafodipir intravenously at a rate of 1 mL/minute for a total dose of 5 μmol/kg body weight. Nine healthy adult volunteers (6 men/3 women; median age, 43 years) completed baseline history and physical examination, 3T MR imaging, and blood work. MR imaging also followed mangafodipir administration at various time points from immediate to 7 days, with delayed scans at 1-3 months.
RESULTS
The choroid plexus and anterior pituitary gland enhanced within 10 minutes of infusion, with enhancement persisting up to 7 and 30 days, respectively. Exocrine (parotid, submandibular, sublingual, and lacrimal) glands also enhanced avidly as early as 1 hour postadministration, generally resolving by 1 month; 3 volunteers had residual exocrine gland enhancement, which resolved by 2 months in 1 and by 3 months in the other 2. Mangafodipir did not affect clinical parameters, laboratory values, or T1-weighted signal in the basal ganglia.
CONCLUSIONS
Manganese ions released from mangafodipir successfully enable noninvasive visualization of intra- and extracranial structures that lie outside the blood-brain barrier without adverse clinical effects, setting the stage for future neuroradiologic investigation in disease.
Topics: Adult; Brain; Contrast Media; Edetic Acid; Female; Healthy Volunteers; Humans; Image Enhancement; Magnetic Resonance Imaging; Male; Pyridoxal Phosphate
PubMed: 31371354
DOI: 10.3174/ajnr.A6152 -
Molecules (Basel, Switzerland) Oct 2022This paper presents the data of research studies on the mechanisms, kinetics and thermodynamics of decomposition of three high-energy compounds:...
This paper presents the data of research studies on the mechanisms, kinetics and thermodynamics of decomposition of three high-energy compounds: [1,2,4]triazolo[4,3-][1,2,4,5]tetrazine-3,6-diamine (TTDA), 3-amino-6-hydrazino[1,2,4]triazolo[4,3-][1,2,4,5]tetrazine (TTGA) and 3,6-dinitroamino[1,2,4]triazolo[4,3-][1,2,4,5]tetrazine (DNTT). The points of change of the reaction mechanisms under thermal effects with different intensities from 0.1 to 2000 s have been established. The values of activation and induction energies for the limiting stages of decomposition have been obtained. The formation of nanostructured carbon nitride (α-CN) in condensed decomposition products, cyanogen (CN) and hydrogen cyanide (HCN) in gaseous products have been shown. Concentration-energy diagrams for the reaction products have been compiled. The parameters of heat resistance and thermal safety proved to be: 349.5 °C and 358.2 °C for TTDA; 190.3 °C and 198.0 °C for TTGA; 113.4 °C and 114.1 °C for DNTT. The energy and thermodynamic properties have also been estimated. This work found the activation energy of the decomposition process to be 129.0 kJ/mol for TTDA, 212.2 kJ/mol for TTGA and 292.2 kJ/mol for DNTT. The average induction energy of the catalytic process (Ecat) for TTGA was established to be 21 kJ/mol, and for DNTT-1500-1700 kJ/mol. The induction energy of the inhibition process (Eing) of TTDA was estimated to be 800-1400 kJ/mol.
Topics: Hydrogen Cyanide; Thermodynamics; Kinetics; Hot Temperature; Heterocyclic Compounds; Diamines
PubMed: 36296568
DOI: 10.3390/molecules27206966 -
Environmental Science and Pollution... Dec 2022The adsorption of Cr ions from water-soluble solution onto activated pea peels (PPs) embellished with triethylenetetramine (TETA) was studied. The synthesized activated...
The adsorption of Cr ions from water-soluble solution onto activated pea peels (PPs) embellished with triethylenetetramine (TETA) was studied. The synthesized activated TETA-PP biosorbent was further characterized by SEM together with EDX, FTIR and BET to determine the morphology and elementary composition, functional groups (FGs) present and the biosorbent surface area. The confiscation of Cr ions to activated TETA-PP biosorbent was observed to be pH-reliant, with optimum removal noticed at pH 1.6 (99%). Cr ion adsorption to activated TETA-PP biosorbent was well defined using the Langmuir (LNR) and the pseudo-second-order (PSO) models, with a determined biosorption capacity of 312.50 mg/g. Also, it was found that the activated TETA-PP biosorbent can be restored up to six regeneration cycles for the sequestration of Cr ions in this study. In comparison with other biosorbents, it was found that this biosorbent was a cost-effective and resourceful agro-waste for the Cr ion confiscation. The possible mechanism of Cr to the biosorbent was by electrostatic attraction following the surface protonation of the activated TETA-PP biosorbent sites.
Topics: Trientine; Pisum sativum
PubMed: 35881295
DOI: 10.1007/s11356-022-21957-6 -
Cell Biochemistry and Function Aug 2020For successful implantation, endometrial receptivity must be established. The high expression of CDC20 in many kinds of malignant tumours has been reported, and it is...
For successful implantation, endometrial receptivity must be established. The high expression of CDC20 in many kinds of malignant tumours has been reported, and it is related to the occurrence and development of tumours. According to these functions, we think that CDC20 may also play important roles in the process of embryo implantation. To prove our hypothesis, we observed the distribution and expression of CDC20 in mouse and human early pregnancy. The effect of E2 and/or P4 on the expression of CDC20 in human endometrial cells was detected by Western blot. To further explore whether CDC20 is an important factor in adhesion and proliferation. The results showed that the expression of CDC20 in the uterus and menstrual cycle of early pregnant mice was spatiotemporal. E2 can promote the expression of CDC20. On the contrary, P4 and E2 + P4 inhibited the expression of CDC20. We also detected the proliferation and adhesion of human endometrial cells. We found that the inhibition of CDC20 with its inhibitor Apcin could reduce the adhesion rate and proliferation ability to RL95-2 and HEC-1A cells, respectively. Inhibiting CDC20 by Apcin could interfere the embryo implantation of mouse. It is suggested that CDC20 may play an important role in the process of embryo implantation. SIGNIFICANCE OF THE STUDY: Embryo implantation is an extremely complex and delicate process, including identification, localisation, adhesion and invasion between embryo and endometrium. Studies have shown the process of embryo implantation is very similar to that of tumour invasion. CDC20 is a cancer-promoting factor. We found CDC20 is spatially and spatially expressed in mouse and human menstrual cycles and is regulated by oestrogen and progesterone. Apcin can inhibit the adhesion of JAR cells and embryo implantation of mouse. CDC20 may provide a new way to improve the success rate of assisted reproduction.
Topics: Animals; Carbamates; Cdc20 Proteins; Cell Adhesion; Cell Proliferation; Cells, Cultured; Diamines; Embryo Implantation; Endometrium; Epithelial Cells; Estrogens; Estrus; Female; Humans; Menstrual Cycle; Mice; Uterus
PubMed: 32458533
DOI: 10.1002/cbf.3550 -
Cell Communication and Signaling : CCS Nov 2019Notch1 signalling is a stem-cell-related pathway that is essential for embryonic development, tissue regeneration and organogenesis. However, the role of Notch1 in the...
BACKGROUND
Notch1 signalling is a stem-cell-related pathway that is essential for embryonic development, tissue regeneration and organogenesis. However, the role of Notch1 in the formation of myofibroblasts and fibrosis in kidneys following injury remains unknown.
METHODS
The activity of Notch1 signalling was evaluated in fibrotic kidneys in CKD patients and in ureteral obstructive models in vivo and in cultured fibroblasts and TECs in vitro. In addition, the crosstalk of Notch1 with TGF-β1/Smad2/3 signalling was also investigated.
RESULTS
Notch1 activity was elevated in fibrotic kidneys of rat models and patients with chronic kidney disease (CKD). Further study revealed that epithelial and interstitial Notch1 activity correlated with an α-SMA-positive myofibroblastic phenotype. In vitro, injury stimulated epithelial Notch1 activation and epithelial-mesenchymal transition (EMT), resulting in matrix deposition in tubular epithelial cells (TECs). Additionally, interstitial Notch1 activation in association with fibroblast-myofibroblast differentiation (FMD) in fibroblasts mediated a myofibroblastic phenotype. These TGF-β1/Smad2/3-dependent phenotypic transitions were abolished by Notch1 knockdown or a specific antagonist, DAPT, and were exacerbated by Notch1 overexpression or an activator Jagged-1-Fc chimaera protein. Interestingly, as a major driving force behind the EMT and FMD, TGF-β1, also induced epithelial and interstitial Notch1 activity, indicating that TGF-β1 may engage in crosstalk with Notch1 signalling to trigger fibrogenesis.
CONCLUSION
These findings suggest that epithelial and interstitial Notch1 activation in kidneys following injury contributes to the myofibroblastic phenotype and fibrosis through the EMT in TECs and to the FMD in fibroblasts by targeting downstream TGF-β1/Smad2/3 signalling.
Topics: Animals; Cell Line; Diamines; Disease Models, Animal; Epithelial Cells; Fibrosis; Humans; Male; Myofibroblasts; Phenotype; Rats; Rats, Sprague-Dawley; Receptor, Notch1; Signal Transduction; Thiazoles
PubMed: 31718671
DOI: 10.1186/s12964-019-0455-y -
Clinical Chemistry and Laboratory... Nov 2023C-peptide and insulin are peptide hormones and their stability is affected by a number of pre-analytical factors. The study aimed to investigate the impact of sample...
OBJECTIVES
C-peptide and insulin are peptide hormones and their stability is affected by a number of pre-analytical factors. The study aimed to investigate the impact of sample type, storage temperature and time delays before centrifugation and analysis on the stability of C-peptide and insulin.
METHODS
Ten healthy non-diabetic adults in fasting and non-fasting state were enrolled. 40 mL of blood was collected from each participant into SST and dipotassium EDTA tubes. Samples were centrifuged immediately or at timed intervals (8, 12, 48 and 72 h). After baseline measurements on the Roche Cobas e602 analyzer using electrochemiluminescence immunoassays, aliquots were stored at room temperature (RT), 2-8 and -20 °C for 4 h to 30 days. The percentage deviation (PD) from baseline was calculated and a change greater than desirable biological variation total error was considered clinically significant.
RESULTS
C-peptide was more stable in separated serum than plasma (PD of -5 vs. -13 %) samples stored at 2-8 °C for 7 days and was most unstable at RT when centrifugation was delayed (PD -46 % in plasma and -74 % in serum after 48 h). Insulin was more stable in plasma than in serum under the different storage conditions with a minimum PD of -1% when stored at -20 °C for 30 days. When samples were kept unspun at RT for 72 h, PD was -23 and -80 % in plasma and serum, respectively.
CONCLUSIONS
C-peptide was more stable in serum provided the sample was centrifuged immediately and stored in the fridge or freezer while insulin was found to be more stable in EDTA plasma.
Topics: Adult; Humans; Insulin; C-Peptide; Edetic Acid; Plasma; Serum; Blood Specimen Collection; Temperature
PubMed: 37409980
DOI: 10.1515/cclm-2023-0339 -
Biomedicine & Pharmacotherapy =... Jul 2022Jellyfish envenomation is a common medical problem in many countries. However, the myotoxicity and effector molecules of scyphozoan venoms remain uninvestigated. Here,...
Jellyfish envenomation is a common medical problem in many countries. However, the myotoxicity and effector molecules of scyphozoan venoms remain uninvestigated. Here, we present the myotoxicity of nematocyst venom from Nemopilema nomurai (NnNV), a giant venomous scyphozoan from China, for the first time, using in vivo models with inhibitors. NnNV was able to induce remarkable myotoxicity including significant muscle swelling, increasing the content of CK and LDH in serum, stimulating inflammation of muscle tissue, and destroying the structure of muscle tissue. In addition, the metalloproteinase inhibitors BMT and EDTA significantly reduced the myotoxicity induced by NnNV. Moreover, BMT and EDTA could decrease the inflammatory stimulation and necrosis of muscle tissue caused by the venom. These observations suggest that the metalloproteinase components of NnNV make a considerable contribution to myotoxicity. This study contributes to understanding the effector molecules of muscle injury caused by jellyfish stings and suggests a new idea for the treatment of scyphozoan envenomation.
Topics: Animals; Cnidarian Venoms; Edetic Acid; Metalloproteases; Myotoxicity; Scyphozoa
PubMed: 35644119
DOI: 10.1016/j.biopha.2022.113192