An Octacarboxylate-Linked Sodium Metal-Organic Framework with High Porosity.

Alkali metal-based metal-organic frameworks (MOFs) with permanent porosity are scarce because of their high tendency to coordinate with solvents such as water. However, these MOFs are lightweight and bear gravimetric benefits for gas adsorption related applications. In this study, we present the successful construction of a microporous MOF, designated as HIAM-111, built solely on sodium ions by using an octacarboxylate linker. The structure of HIAM-111 is based on 8-connected Na4 clusters and exhibits a novel topology with an underlying 32,42,8-c net. Remarkably, HAM-111 possesses a robust and highly porous framework with a BET surface area of 1561 m2/g, significantly surpassing that of the previously reported Na-MOFs. Further investigations demonstrate that HIAM-111 is capable of separating C2H2/CO2 and purifying C2H4 directly from C2H4/C2H2/C2H6 with high adsorption capacities. The current work may shed light on the rational design of robust and porous MOFs based on alkali metals.

Melatonin-priming enhances maize seedling drought tolerance by regulating the antioxidant defense system.

Drought stress (DS) challenges sustainable agriculture production by limiting crop growth and development. The objective of the study was to evaluate the effect of melatonin-priming on enzymatic and non-enzymatic antioxidant defense mechanisms and its relation with leaf ultrastructure and stomatal traits in maize (Zea mays L) seedlings under DS (PEG-6000). DS drastically decreased seed germination, plant growth, and leaf chlorophyll content due to excessive reactive oxygen species (ROS) production. Melatonin-priming significantly (P < 0.05) increased seed germination, root length, shoot length, fresh seedling weight, proline content, total soluble protein content, sugar content, chlorophyll content, and stomatal aperture size by 101%, 30%, 133%, 51%, 22%, 59%, 54%, 20%, and 424%, compared to no priming (NP) under DS, respectively. Similarly, priming improved leaf ultrastructure and reduced the amount of chlorophyll loss and oxidative damage in maize seedlings. Melatonin seed priming with 500 µM melatonin (M2) greatly increased superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione, and ascorbate (AsA) activity, by 65%, 63%, 94%, 41%, and 55% compared to NP under DS and by 0.26%, 8%, 33%, 42%, and 15% under no-stress (NS), respectively. Melatonin-priming also reduced malondialdehyde content, electrolyte leakage, hydrogen peroxide (H2O2) content, and superoxide anion (O2-) content by 26%, 31%, 31%, and 33% compared to NP under DS and by 8%, 18%, 10%, and 11% under NS, respectively. In response to DS, melatonin-priming also stabilized the chloroplast structure, sustained cell expansion, protected cell walls, and greatly improved stomatal traits, including stomatal number, length, and width. Our results suggest that melatonin-priming improves drought tolerance in maize seedlings by alleviating the negative effect of ROS.

Analysis of physiological response and differential protein expression of Paramichelia baillonii saplings under phosphorus deficiency.

Paramichelia baillonii is a rare and fast-growing tree species in subtropical China. The acidic red soil in southern China severely limits its growth as it lacks sufficient available phosphorus (P), resulting in declining soil fertility and nutrient availability. The effect of P deficiency on P. Baillonii growth, root attributes, and physiological response has not yet been reported. Understanding the adaptability of P. baillonii to low-P conditions can improve afforestation and soil management in southern China. Therefore, we conducted a pot experiment on 2-year-old saplings and treated them with different P levels. Results showed that P deficiency (0-5 mg L-1 ) decreased growth attributes, root morphological traits, and nutrient uptake of P. baillonii saplings compared to control (CK). Similarly, reduction in chlorophyll a, b, total chlorophyll, net photosynthetic rate (Pn), transpiration rate (Tr), and Gs were seen in low P treatment saplings compared to CK. Whereas superoxide dismutase, peroxidase, malondialdehyde, acid phosphatase activity, and soluble protein content increased with increasing P-deficiency up to 5 mg L-1 , and soluble sugar showed oppsite trend. Moreover, the proteomics analysis identified 2721 proteins, 196 showing differential expression, with 90 up- and 106 down-regulated. Importantly, the metabolic activities increased in the pentose phosphate pathway, starch and sucrose metabolism, amino sugar and nucleotide sugar metabolism, and phenylpropanoid biosynthesis pathways to sustain regular plant growth under P deficiency. This study delves into the dynamic morpho-physiological and proteomic changes in response to P deficiency. Overall, growth and nutrient uptake were reduced, countered by adaptive biochemical and proteomic shifts, including heightened antioxidant activities and modifications in metabolic pathways, highlighting the resilient strategies of P. baillonii saplings under P deficiency.

The efficacy and safety of snare traction-assisted endoscopic submucosal dissection for circumferential superficial esophageal cancer.

OBJECTIVE: This study aims to investigate the efficacy and safety of snare traction-assisted endoscopic submucosal dissection (ESD) for the management of circumferential superficial esophageal cancer. METHODS: A total of 68 patients who underwent ESD for circumferential superficial esophageal cancer were included in this study. All the patients were divided into two groups based on whether the snare traction was used or not; the snare traction group (S-ESD, group n = 35) and the control group (C-ESD, group n = 33). RESULTS: There was no significant difference in the size of the resected area between the groups [21.98 (18.30, 27.00) cm2 vs 24.00 (15.28, 30.72) cm2, P = 0.976]. The snare traction group had a shorter dissection time [92.00 (74.00, 121.00) min vs 110.00 (92.50, 137.00) min, P = 0.017] and a faster resection speed [0.28 ± 0.13 cm2/min vs 0.22 ± 0.11cm2/min, P = 0.040] compared to the control group. There were no statistically significant differences between the two groups in terms of hospital stay, cost, en bloc resection rate, R0 resection rate, curative resection rate, bleeding rate, perforation rate, stricture rate, and recurrence rate (P > 0.05). CONCLUSION: Snare traction-assisted ESD is a safe and efficient approach for the treatment of circumferential superficial esophageal cancer. Its advantages includes shorter procedure so the anesthesia requirement, clear operative filed view, improved mucosal dissection efficiency, simple, and easily accessible equipment.

Di-(2-ethylhexyl) phthalate (DEHP) contamination suppressed soil microbial biomass carbon and mitigated CO2 emissions against the background of alfalfa from different soils.

Plastic mulching and organic amendments are prevalent agricultural practices worldwide. Plastic mulching has long been suspected as a significant source of DEHP contamination in terrestrial ecosystems. However, effects of DEHP contamination on greenhouse gas emissions and microbial biomass carbon (MBC) remain unclear. Here, a microcosm experiment was set up to assess the impact of DEHP exposure on MBC and carbon dioxide (CO2) emission in two different soils (acidic and alkaline) with the inclusion of alfalfa straw. The treatment includes: (i) control with no amendment (T1); (ii) alfalfa straw addition (20 g kg-1) (T2); (iii) DEHP (10 mg kg-1) + alfalfa straw (T3); and (iv) DEHP (100 mg kg-1) + alfalfa straw (T4). Against the background of alfalfa inclusion, DEHP exposure led to a potential reduction in cumulative CO2 emissions by 16.35 % and 6.91 % in alkaline soil and 12.27 % and 13.65 % in acidic soil for T3 and T4, respectively. The addition of DEHP triggered CO2 emissions and manifested a detrimental negative priming effect in both soil types. In both soils, average CO2 emission fluxes were highest for the T2 treatment. The MBC fluctuated at around 80 mg kg-1 for the control group, alfalfa straw alone (T2) treatment considerably enhanced MBC contents, whereas DEHP contamination in T3 and T4 treatments suppressed the stimulatory effect of alfalfa on MBC in both alkaline and acidic soils. Furthermore, a positive relationship was observed between soil CO2 emissions and MBC in both soils. Overall, these findings highlight the toxic impact of DEHP on MBC and its role in mitigating CO2 emissions in diverse soils. DEHP exposure counters the CO2 emissions induced by alfalfa straw. In addition, the inhibitory effect of DEHP on CO2 fluxes in alkaline soil is less pronounced than in acidic soil. Therefore, further cutting-edge research is crucial since DEHP contamination poses serious ecological threats to agroecosystems.

Fault Diagnosis of a Multistage Centrifugal Pump Using Explanatory Ratio Linear Discriminant Analysis.

This study introduces an innovative approach for fault diagnosis of a multistage centrifugal pump (MCP) using explanatory ratio (ER) linear discriminant analysis (LDA). Initially, the method addresses the challenge of background noise and interference in vibration signals by identifying a fault-sensitive frequency band (FSFB). From the FSFB, raw hybrid statistical features are extracted in time, frequency, and time-frequency domains, forming a comprehensive feature pool. Recognizing that not all features adequately represent MCP conditions and can reduce classification accuracy, we propose a novel ER-LDA method. ER-LDA evaluates feature importance by calculating the explanatory ratio between interclass distance and intraclass scatteredness, facilitating the selection of discriminative features through LDA. This fusion of ER-based feature assessment and LDA yields the novel ER-LDA technique. The resulting selective feature set is then passed into a k-nearest neighbor (K-NN) algorithm for condition classification, distinguishing between normal, mechanical seal hole, mechanical seal scratch, and impeller defect states of the MCP. The proposed technique surpasses current cutting-edge techniques in fault classification.

Pipeline Leak Detection: A Comprehensive Deep Learning Model Using CWT Image Analysis and an Optimized DBN-GA-LSSVM Framework.

Detecting pipeline leaks is an essential factor in maintaining the integrity of fluid transport systems. This paper introduces an advanced deep learning framework that uses continuous wavelet transform (CWT) images for precise detection of such leaks. Transforming acoustic signals from pipelines under various conditions into CWT scalograms, followed by signal processing by non-local means and adaptive histogram equalization, results in new enhanced leak-induced scalograms (ELIS) that capture detailed energy fluctuations across time-frequency scales. The fundamental approach takes advantage of a deep belief network (DBN) fine-tuned with a genetic algorithm (GA) and unified with a least squares support vector machine (LSSVM) to improve feature extraction and classification accuracy. The DBN-GA framework precisely extracts informative features, while the LSSVM classifier precisely distinguishes between leaky and non-leak conditions. By concentrating solely on the advanced capabilities of ELIS processed through an optimized DBN-GA-LSSVM model, this research achieves high detection accuracy and reliability, making a significant contribution to pipeline monitoring and maintenance. This innovative approach to capturing complex signal patterns can be applied to real-time leak detection and critical infrastructure safety in several industrial applications.

Diuretic effects of Hecogenin and Hecogenin acetate via aldosterone synthase inhibition.

Hecogenin (HEC) is a steroidal saponin found in many plant species and serves as a precursor for steroidal drugs. The diuretic effects of HEC and its derivative, hecogenin acetate (HA), remain largely unexplored. The present study aimed to explore the potential diuretic effects of HEC and HA compared to furosemide (FUR) and spironolactone (SPIR). Additionally, the study aimed to explore the underlying mechanism particularly focusing on aldosterone synthase gene expression. Fifty-four Sprague-Dawley rats were allocated into nine groups (Group 1-9). Group 1 (control) received the vehicle, Groups 2 received FUR 10 mg/kg, Group 3, 4, and 5 were given HEC, while Groups 6, 7 and 8 received HA i.p at doses of 5, 10, and 25 mg/kg, respectively. Group 9 received SPIR i.p at the dose of 25 mg/kg. Urine volume, diuretic index and diuretic activity were monitored at 1, 2, 3, 4, 5, 6, and 24 h post-administration. Treatment was given daily for seven days. After that, rats were sacrificed and blood was collected for serum electrolytes determination. Adrenal glands were dissected out for gene expression studies. The results revealed that HEC and HA at the administered doses significantly and dose-dependently increased urine and electrolyte excretion. These results were primarily observed at 25 mg/kg of each compound. Gene expression studies demonstrated a dose-dependent reduction in aldosterone synthase gene expression, suggesting aldosterone synthesis inhibition as a potential mechanism for their diuretic activity. Notably, HA exhibited more pronounced diuretic effects surpassing those of HEC. This enhanced diuretic activity of HA can be attributed to its stronger impact on aldosterone synthase inhibition. These findings offer valuable insights into the diuretic effects of both HEC and HA along with their underlying molecular mechanisms.

Magnetically Induced Binary Ferrocene with Oxidized Iron.

Ferrocene is perhaps the most popular and well-studied organometallic molecule, but our understanding of its structure and electronic properties has not changed for more than 70 years. In particular, all previous attempts of chemically oxidizing pure ferrocene by binding directly to the iron center have been unsuccessful, and no significant change in structure or magnetism has been reported. Using a metal organic framework host material, we were able to fundamentally change the electronic and magnetic structure of ferrocene to take on a never-before observed physically stretched/bent high-spin Fe(II) state, which readily accepts O2 from air, chemically oxidizing the iron from Fe(II) to Fe(III). We also show that the binding of oxygen is reversible through temperature swing experiments. Our analysis is based on combining Mößbauer spectroscopy, extended X-ray absorption fine structure, in situ infrared, SQUID, thermal gravimetric analysis, and energy dispersive X-ray fluorescence spectroscopy measurements with ab initio modeling.

Endoscopic Retrograde Appendicitis Therapy: Is it Really a Need of the Hour?

ABSTRACT: Endoscopic retrograde appendicitis therapy (ERAT) has emerged as a promising, non-invasive treatment for acute uncomplicated appendicitis (AUA). ERAT involves cannulation, appendicography, appendiceal stone extraction, appendiceal lumen irrigation, and stent deployment. Recent randomized trials comparing ERAT to laparoscopic appendectomy (LA) have provided promising results in terms of safety and efficacy of ERAT. If the current trajectory of research and development is maintained, ERAT will likely become a strong contender for the standard of care for AUA. Standardized training and credentialing for ERAT, akin to procedures established for endoscopic retrograde cholangiopancreatography, will be pivotal to global adoption of this modality.

Precise Pore Engineering of fcu-Type Y-MOFs for One-Step C2 H4 Purification from Ternary C2 H6 /C2 H4 /C2 H2 Mixtures.

The purification of C2 H4 from C2 H6 /C2 H4 /C2 H2 mixtures is of great significance in the chemical industry for C2 H4 production but remains a daunting task. Guided by powerful reticular chemistry principles, herein a systematic study is carried out to engineer pore dimensions and pore functionality of fcu-type Y-based metal-organic frameworks (Y-MOFs) through the construction of a series of eight new structures using linear dicarboxylate linkers with different length and functional groups. This study illustrates how delicate changes in pore size and pore surface chemistry can effectively influence the adsorption preference of C2 H6 , C2 H4 , and C2 H2 by the MOFs. Importantly, clear relations between pore size/pore surface polarity and C2 adsorption selectivities of this series of MOFs are established. In particular, HIAM-326 built on a linker decorated with trifluoromethoxy group shows notably preferential adsorption of C2 H6 and C2 H2 over C2 H4 , with balanced C2 H2 /C2 H4 and C2 H6 /C2 H4 selectivities. This endows the compound with the capability of one-step purification of C2 H4 from C2 H6 /C2 H4 /C2 H2 ternary mixtures, which is validated by breakthrough measurements where high purity C2 H4 (99.9%+) can be obtained directly from the separation column. Its adsorption thermodynamics and underlying selective adsorption mechanisms are further revealed by ab initio calculations.

Luminescent Metal-Organic Framework for the Selective Detection of Aldehydes.

The detection of toxic, hazardous chemical species is an important task because they pose serious risks to either the environment or human health. Luminescent metal-organic frameworks (LMOFs) as alternative sensors offer rapid and sensitive detection of chemical species. Interactions between chemical species and LMOFs result in changes in the photoluminescence (PL) profile of the LMOFs which can be readily detected using a simple fluorometer. Herein, we report the use of a robust, Zn-based LMOF, [Zn5(µ3-OH)2(adtb)2(H2O)5·5 DMA] (Zn-adtb, LMOF-341), for the selective detection of benzaldehyde. Upon exposure to benzaldehyde, Zn-adtb experiences significant luminescent quenching, as characterized through PL experiments. Photoluminescent titration experiments reveal that LMOF-341 has a detection limit of 64 ppm and a Ksv value of 179 M-1 for benzaldehyde. Furthermore, we study the guest-host interactions that occur between LMOF-341 and benzaldehyde through in situ Fourier transform infrared and computational modeling employing density functional theory. The results show that benzaldehyde interacts more strongly with LMOF-341 compared to formaldehyde and propionaldehyde. Our combined studies also reveal that the mechanism of luminescence quenching originates from an electron-transfer process.

Inclusion of the fungus Pleurotus florida in the diet affects performance and feed efficiency traits in calves: a case study on Ravi buffalo.

The objective of the study was to investigate the effects of inclusion of Pleurotus florida treated wheat straw in the total mixed rations (TMRs) on feed intake, growth performance, nutrient digestibility, and nitrogen retention in male buffalo calves. As a pilot study, four TMRs, i.e., TMR1 having 0% P. florida treated wheat straw (FTWS), TMR2 (20% FTWS), TMR3 (40% FTWS), and TMR4 (60% FTWS) with berseem hay as basal diet, were formulated. Sixteen Nili-Ravi male buffalo calves (aged 10-12 months, weighing 73 ± 2.50 kg) were divided into four equal groups and randomly assigned one of four TMRs. A significant increase (P < 0.05) was observed in all nutrients intake, their digestibility, weight gain, and nitrogen retention with TMRs incorporated with FTWS. Highest feed conversion ratio (FCR) of 2.63 was noted with TMR1-0% and the lowest FCR (1.80) with TMR4-60%, on the other hand. In conclusion, the TMR4 (60% FTWS) has the potential to increase the weight gain, nutrient digestibility, nitrogen retention, and feed efficiency in buffalo calves. Therefore, inclusion of 60% Pleurotus florida treated wheat straw is recommended as TMRs with berseem hay based basal diet for feeding buffaloes calves.

Separating Xylene Isomers with a Calcium Metal-Organic Framework.

The purification of p-xylene (pX) from its xylene isomers represents a challenging but important industrial process. Herein, we report the efficient separation of pX from its ortho- and meta- isomers by a microporous calcium-based metal-organic framework material (HIAM-203) with a flexible skeleton. At 30 °C, all three isomers are accommodated but the adsorption kinetics of o-xylene (oX) and m-xylene (mX) are substantially slower than that of pX, and at an elevated temperature of 120 °C, oX and mX are fully excluded while pX can be adsorbed. Multicomponent column breakthrough measurements and vapor-phase/liquid-phase adsorption experiments have demonstrated the capability of HIAM-203 for efficient separation of xylene isomers. Ab initio calculations have provided useful information for understanding the adsorption mechanism.

Tuning Metal-Organic Framework (MOF) Topology by Regulating Ligand and Secondary Building Unit (SBU) Geometry: Structures Built on 8-Connected M6 (M = Zr, Y) Clusters and a Flexible Tetracarboxylate for Propane-Selective Propane/Propylene Separation.

Topology evolution originating from variations of linker and SBU (Secondary Building Unit) geometries could largely enrich the chemistry of metal-organic frameworks (MOFs). Here we report the synthesis and characterization of three MOF structures built on the same organic linker, N,N,N',N'-Tetrakis(4-carboxyphenyl)-1,4-phenylenediamine (tcppda) and similar 8-connected M6 (M = Zr or Y) clusters. The three compounds, HIAM-402, HIAM-403, and HIAM-311, feature 4,8-connected sqc, scu, and flu topology, respectively. Detailed structural analysis revealed that different geometries of the inorganic M6 SBUs as well as the organic linker have led to the formation of distinct MOF nets. In particular, HIAM-402 features exceptional framework stability and high porosity and acts as a propane-selective adsorbent for the discrimination of propane and propylene. Its balanced adsorption selectivity (Spropane/propylene = 1.43) and capacity (Qpropane = 133.3 cm3/g, 298 K and 1 bar) endow it with the capability of separating propane and propylene mixtures and one-step production of highly pure propylene (purity >99.9%), as validated by column breakthrough measurements, with the presence of moisture or propyne. Ab initio calculations further confirm that the propane-selective behavior of HIAM-402 is a result of its higher binding energy toward propane compared to that of propylene.

A Microporous Metal-Organic Framework Incorporating Both Primary and Secondary Building Units for Splitting Alkane Isomers.

We demonstrate the assembly of a mononuclear metal center, a hexanuclear cluster, and a V-shaped, trapezoidal tetracarboxylate linker into a microporous metal-organic framework featuring an unprecedented 3-nodal (4,4,8)-c lyu topology. The compound, HIAM-302, represents the first example that incorporates both a primary building unit and a hexanuclear secondary building unit in one structure, which should be attributed to the desymmetrized geometry of the organic linker. HIAM-302 possesses optimal pore dimensions and can separate monobranched and dibranched alkanes through selective molecular sieving, which is of significant value in the petrochemical industry.

Endoscopic retrograde appendicitis therapy versus laparoscopic appendectomy for uncomplicated acute appendicitis.

BACKGROUND: Endoscopic retrograde appendicitis therapy (ERAT) is a new and minimally invasive technique for the treatment of acute appendicitis. This study aimed to assess the efficacy and clinical outcomes of ERAT versus laparoscopic appendectomy for patients with uncomplicated acute appendicitis. METHODS: We adopted propensity score matching (1:1) to compare ERAT and laparoscopic appendectomy in patients with uncomplicated acute appendicitis between April 2017 and March 2020. We reviewed 2880 patients with suspected acute appendicitis, of whom 422 patients with uncomplicated acute appendicitis met the matching criteria (ERAT 79; laparoscopic appendectomy 343), yielding 78 pairs of patients. RESULTS: The rate of curative treatment within 1 year after ERAT was 92.1 % (95 % confidence interval [CI] 83.8 % to 96.3 %). The percentage of patients recording visual analog scale values of  ≤ 3 for pain at 6 hours after treatment was 94.7 % (95 %CI 87.2 % to 97.9 %) in the ERAT group, which was significantly higher than that in the laparoscopic appendectomy group (83.3 %; 95 %CI 73.5 % to 90.0 %). Median procedure time and median hospital length of stay were significantly lower in the ERAT group compared with the laparoscopic appendectomy group. At 1 year, the median recurrence time was 50 days (interquartile range 25-127) in the ERAT group. The overall adverse event rate was 24.4 % (95 %CI 14.8 % to 33.9 %) in the laparoscopic appendectomy group and 18.4 % (95 %CI 9.7 % to 27.1 %) in the ERAT group, with no significant difference between the two groups. CONCLUSION: ERAT was a technically feasible method of treating uncomplicated acute appendicitis compared with laparoscopic appendectomy.

Digital single-operator cholangioscope for endoscopic retrograde appendicitis therapy.

BACKGROUND: This study aimed to investigate the diagnostic and therapeutic value of a digital single-operator cholangioscope (SOC) system for endoscopic management of acute appendicitis. METHODS: 14 patients with acute uncomplicated simple or supportive appendicitis were evaluated between November 2018 and September 2020. The diagnosis of acute appendicitis was confirmed by direct colonoscopy imaging and cholangioscope. The success rate of digital SOC-assisted endoscopic retrograde appendicitis therapy (ERAT), the procedure time, postoperative length of hospital stay, complications, and recurrence rate were recorded. RESULTS: Technical success rate was 100 %, with high quality imaging of the appendiceal cavity achieved using SOC in all 14 patients. The mean procedure time was 37.8 (standard deviation [SD] 22) minutes. All patients experienced immediate relief from abdominal pain after the procedure. Mean postoperative hospitalization was 1.9 (SD 0.7) days. No recurrence occurred during 2-24 months of follow-up. CONCLUSION: Digital SOC-assisted ERAT provided a feasible, safe, and effective alternative approach for diagnosis and management of acute uncomplicated appendicitis without the need for X-ray or ultrasonic guidance.

Identification of thienopyrimidine glycinates as selective inhibitors for h-NTPDases.

The h-NTPDases is an essential family of ectonucleotidases that consists of eight isozymes with various physiological functions. The undesired activity of the h-NTPDases leads to pathological conditions such as cancer, diabetes, inflammation, and thrombosis. In the present study, a series of thienopyrimidines was synthesized employing a sequential SNAr and Suzuki coupling to synthesize diverse aryl substituted thienopyrimidine glycinate derivatives. The synthesized compounds constituted electron donating, electron-deficient, heteroaryl, and fluorinated substituents. The thienopyrimidines were screened against h-NTPDases to determine the effect on the activity of the h-NTPDases-1, -2, -3, and -8. The compound 3j selectively blocked the isozyme h-NTPDases1, while the compounds 3e, 3m, and 4a were selective inhibitors of h-NTPDases2. The activity of the isozyme h-NTPDases3 was selectively reduced by inhibitor 3k whereas, the compound 3d was found as the most active inhibitor against isozyme h-NTPDase8. The molecular docking study interpreted the interactions of the potent inhibitors of the respective isozymes with important amino acid residues i.e., Asp54, Ser57, His59, Ser58, His59, Asp213, and Phe360 of h-NTPDases1 protein; residues Arg 392, Ala393, Ala347, Tye350 and Arg245 of h-NTPDases2; amino acids Arg67, Ser65, Ala323, Gly222, and Tyr375 of h-NTPDases3 whereas in case of h-NTPDases8, the residues Val436, Gln74, Gly179, and Val71 were involved in interaction with the inhibitors docked into the active sites of these isozymes.

Effects of Elevated Aluminum Concentration and Distribution on Root Damage, Cell Wall Polysaccharides, and Nutrient Uptake in Different Tolerant Eucalyptus Clones.

Aluminized acidic soil can damage Eucalyptus roots and limit tree growth, hindering the productivity of Eucalyptus plantations. At present, the negative impacts of elevated aluminum (Al) on the cell morphology and cell wall properties of Eucalyptus root tip are still unclear. In order to investigate the responses of two different tolerant clones, Eucalyptus urophylla (G4) and Eucalyptus grandis × Eucalyptus urophylla (G9), to Al toxicity, seedling roots were treated hydroponically with an Al solution, and the polysaccharide content in the root tip cell wall and the characteristics of programmed cell death were studied. The results show that the distribution of Al was similar in both clones, although G9 was found to be more tolerant to Al toxicity than G4. The Al3+ uptake of pectin in root tip cell walls was significantly higher in G4 than in G9. The root tip in G4 was obviously damaged, enlarged, thickened, and shorter; the root crown cells were cracked and fluffy; and the cell elongation area was squeezed. The lower cell wall polysaccharide content and PME activity may result in fewer carboxylic groups in the root tip cell wall to serve as Al-binding sites, which may explain the stronger Al resistance of G9 than G4. The uptake of nitrogen and potassium in G4 was significantly reduced after aluminum application and was lower than in G9. Al-resistant Eucalyptus clones may have synergistic pleiotropic effects in resisting high aluminum-low phosphorus stress, and maintaining higher nitrogen and potassium levels in roots may be an important mechanism for effectively alleviating Al toxicity.