Pectate lyases (Pels) have a vital function in degradation of the primary plant cell wall and the middle lamella and have been widely used in the industry. In this study, two pectate lyase genes,
...IDSPel16
and
IDSPel17
, were cloned from a sheep rumen microbiome. The recombinant enzymes were expressed in
Escherichia coli
and functionally characterized. Both IDSPel16 and IDSPel17 proteins had an optimal temperature of 60 ℃, and an optimal pH of 10.0. IDSPel16 was relatively stable below 60 °C, maintaining 77.51% residual activity after preincubation at 60 °C for 1 h, whereas IDSPel17 denatured rapidly at 60 °C. IDSPel16 was relatively stable between pH 6.0 and 12.0, after pretreatment for 1 h, retaining over 60% residual activity. IDSPel16 had high activity towards polygalacturonic acid, with a
V
max
of 942.90 ± 68.11, whereas IDSPel17 had a
V
max
of only 28.19 ± 2.23 μmol/min/mg. Reaction product analyses revealed that IDSPel17 liberated unsaturated digalacturonate (uG
2
) and unsaturated trigalacturonate (uG
3
) from the substrate, indicating a typical endo-acting pectate lyase (EC 4.2.2.2). In contrast, IDSPel16 initially generated unsaturated oligogalacturonic acids, then converted these intermediates into uG
2
and unsaturated galacturonic acid (uG
1
) as end products, a unique depolymerization profile among Pels. To the best of our knowledge, the IDSPel16 discovered with both endo-Pel (EC 4.2.2.2) and exo-Pel (EC 4.2.2.9) activities. These two pectate lyases, particularly the relatively thermo- and pH-stable IDSPel16, will be of interest for potential application in the textile, food, and feed industries.
Key points
•
Two novel pectate lyase genes, IDSPel16 and IDSPel17, were isolated and characterized from the sheep rumen microbiome.
•
Both IDSPel16 and IDSPel17 are alkaline pectate lyases, releasing unsaturated digalacturonate and unsaturated trigalacturonate from polygalacturonic acid.
•
IDSPel16, a bifunctional pectate lyase with endo-Pel (EC 4.2.2.2) and exo-Pel (EC 4.2.2.9) activities, could be a potential candidate for industrial application.
Pillarenes and calixarenes showed obvious inhibition of HPV16 L1 pentamer formation via their selective binding to Arg and Lys residues at the monomer interface, which was reversible after the ...release of cyclic arenes. Pillarenes are more effective than calixarenes in terms of the inhibition efficiency, attributing to the different kinetics and binding affinity.
Low-cycle fatigue (LCF) behavior of the directionally solidified (DS) nickel-based DZ125 superalloy was studied at elevated temperature (980 °C). Specimens were, respectively, exposed for 0, 2, 25, ...50, and 100 h in air. The fatigue life of pre-exposed specimens is lower than that of unexposed specimens. The result is closely associated with fatigue crack initiation and propagation due to oxygen embrittlement and cycle loading. Detailed fractographic evaluations indicate the fatigue life is closely related to the surface microstructural modification. The resulting changes in microstructure cause the decrease in the effective area and the increase in actual stress. A methodology based on the continuum damage mechanics is developed to describe the correlation between the residual LCF life and pre-exposed time.
Nutrient enrichment is a widely recognized threat to coastal coral reefs. Yet its impact on open ocean reefs is largely unknown due to the lack of long-term observations at remote sites and the ...entanglement of various environmental factors affecting coral growth. Here we determined growth rates and the carbonate chemistry of calcifying fluid (CF) of massive corals over the last 550 years at a remote South China Sea reef ecosystem. We show that large growth variations cannot be fully explained by changes in seawater pH or temperature due to the antiphase relationship between growth rate and pHcf as well as small sea surface temperature variations before the 1960s. Instead, coral growth rate decreases proportionally with past seabird populations over the past centuries. We suggest that excess nutrient loads through monsoon pumping and seabird migration played an important role in controlling coral growth at this remote reef ecosystem. Specifically, episodic eutrophication as indicated by a ∼ 3 per mil increase in coral δ13C has depressed coral growth by ∼30% during 15th to 18th centuries, which is comparable to the modern decline. Thus, accurate projections of future coral growth for remote reefs under ongoing human activities and climate change needs to take into account the history of past nutrient inputs into these ecosystems under pre-anthropogenic conditions, which has been overlooked previously due to a lack of historical observations.
•Coral cores from an open ocean reef that grew from ∼1450 to present were analyzed.•Temperature affects multi-decadal variability in coral calcifying fluid DIC but not pH.•Reef-water pH modified by monsoon controls calcifying fluid pH and CO32−•Eutrophication caused by monsoon and seabirds depressed coral growth during the Little Ice Age•An analog to the responses of corals to the projected rise in anthropogenic nutrient inputs.
Endometrial cancer (EC) is one of the most common gynecological cancers, and its risk factors include obesity and metabolic, genetic, and other factors. Recently, the circadian rhythm has also been ...shown to be associated with EC, as the severity of EC was found to be related to night work and rhythm disorders. Therefore, circadian rhythm disorders (CRDs) may be one of the metabolic diseases underlying EC. Changes in the circadian rhythm are regulated by clock genes (CGs), which in turn are regulated by non-coding RNAs (ncRNAs). More importantly, the mechanism of EC caused by ncRNA-mediated CRDs is gradually being unraveled. Here, we review existing studies and reports and explore the relationship between EC, CRDs, and ncRNAs.
Fifteen previously undescribed minor iridoid glycosides, including four monomers and eleven dimers, were isolated from the fruits of Cornus officinalis Sieb. et Zucc. Their chemical structures were ...determined on the basis of spectroscopic data and chemical evidence. All of the isolated compounds were evaluated for their effects of the glucose consumption on the insulin resistant HepG2 cells, and four compounds, named cornuofficinalisides F, H, L, and O, increased the glucose consumption significantly at 10 μM, the EC50 values of them were determined to be 0.898, 1.625, 0.923, and 8.589 μM, respectively. Moreover, the four compounds could improve the ability of glucose uptake significantly in insulin resistant HepG2 cells.
Display omitted
•Fifteen undescribed iridoid glycosides were isolated from the fruits of Cornus officinalis.•Cornuofficinaliside K was a rare secoiridoid glycoside dimer with a big cyclic system.•The isolated compounds were assessed for glucose consumption on the insulin resistant HepG2 cells.
Total Synthesis of (±)-Furanether A Jin, Da-Ping; Gao, Zhu-Peng; Liu, Lin ...
Organic letters,
11/2021, Letnik:
23, Številka:
22
Journal Article
Recenzirano
The first total synthesis of (±)-furanether A, which exhibits good antifeedant activity, has been concisely achieved in 13 linear steps. Notably, the key rigid tetracyclic skeleton containing a ...1-methyl-8-oxabicyclo3.2.1octane moiety with two vicinal quaternary carbon centers was rapidly constructed in one step through a unique tandem C-H oxidation/oxa-3,3 Cope rearrangement/aldol cyclization sequence.
Medical insurance fraud has caused huge losses to countries around the world, and public reporting has become an important means to combat medical insurance fraud. The attitude of medical insurance ...fraud whistleblowers affects people's reporting behavior, and understanding people's attitude toward medical insurance fraud whistleblowers provides a basis for further improving the system and policy of public participation in medical insurance fund supervision.
We adopted the questionnaire method to conduct a national cross-sectional survey of the Chinese public and analyzed the data using Chi-square tests, Fisher's exact tests, and binary logistic regression models.
A total of 837 respondents were included, and 81.8% of the population had a supportive attitude toward medical insurance fraud whistleblowers, with gender, whether they had used medical insurance reimbursement, and present life satisfaction being statistically significant (P < 0.05).
The public is generally supportive of medical insurance fraud whistleblowers, and women, those who have used medical insurance for reimbursement, and those who are satisfied with their lives are more likely to be supportive of medical insurance fraud whistleblowers.
Young and middle-aged people are important participants in the fight against health insurance fraud. The study aims to investigate the differences in their willingness to report health insurance ...fraud and the factors influencing it when it occurs in familiar or unfamiliar healthcare settings.
Data were obtained from a validated questionnaire from 828 young and middle-aged people. McNemar's test was used to compare the public's willingness to report under the two scenarios. Chi-square tests and multiple logistic regression analysis were used to analyze the determinants of individuals' willingness to report health insurance fraud in different scenarios.
Young and middle-aged people were more likely to report health insurance fraud in a familiar healthcare setting than in an unfamiliar one (McNemar's χ²=26.51, P < 0.05). Their sense of responsibility for maintaining the security of the health insurance fund, the government's openness about fraud cases, and the perception of their ability to report had significant positive effects on the public's willingness to report in both settings (P < 0.05). In a familiar healthcare setting, the more satisfied the public is with government measures to protect whistleblowers, the more likely they are to report (OR = 1.44, P = 0.025). Those who perceive the consequences of health insurance fraud to be serious are more likely to report than those who perceive the consequences to be less serious (OR = 1.61, P = 0.042).
Individuals are more likely to report health insurance fraud in familiar healthcare settings than in unfamiliar ones, in which their awareness of the severity of the consequences of health insurance fraud and their perceived risk after reporting it play an important role. The government's publicizing of fraud cases and enhancing the public's sense of responsibility and ability to maintain the safety of the health insurance fund may be a way to increase their willingness to report, regardless of whether they are familiar with the healthcare setting or not.
Debris flow hazards can occur easily in loess regions, due to the particular characteristics of loessic material. Some of them have historically caused considerable damage to both the natural and the ...human environment. Little research has been conducted into the impact pressures caused by debris flows varying with densities and weights in loess regions. Flume experiments were conducted to estimate the impact pressures of debris flows, and the maximum impact pressure was measured. Moreover, hydrodynamic and hydrostatic models were improved by using these experimental results. Finally, after combining these results with a dimensionless analysis and Buckingham’s π theorem, the Froude number and the Reynolds number were able to be introduced in order to construct a comprehensive dimensionless equation for debris flows. The results showed that the velocity ranged from 1.23 to 3.62 m/s when the debris flow density increased from 1100 to 2300 kg/m
3
and the mixture weight rose from 100 to 500 kg. The debris flow depth was between 2.7 and 13.4 cm, and the maximum impact pressure ranged from 1.23 to 28.41 kPa. In addition, the empirical parameters of hydrodynamic and hydrostatic models were modified and valued at 5.08 and 9.48, respectively, which were significantly different from the empirical parameters for earth-rock areas. Specifically, the modified hydrodynamic model and modified hydrostatic model were observed to perform very well for debris flows with comparatively high Froude debris flow numbers. The maximum dimensionless impact pressure was expressed as a power function of both the Froude number and the Reynolds number. A comprehensive maximum dimensionless impact pressure formula for debris flows was coupled with the Froude number and the Reynolds number and expressed as a power function. Results indicated that the modified model and the comprehensive approach can both be applied to the loess regions of China and can provide a better understanding of loess debris flow mechanisms, as well as feed into engineering design work and risk assessments in loess regions affected by debris flows.
