Antifungal activity of star anise extract against Penicillium roqueforti and Aspergillus niger for bread shelf life.

Because star anise is underutilized in the baking sector and the antifungal targets are unclear, this study aimed to investigate the antifungal effect and mechanism of star anise extract (SAE) on spoilage fungi in bread. SAE was prepared by ethanol extraction and 31 substances were identified by GC-MS, among which trans-anethole (62.62%), estragole (7.82%) and linalool (4.66%) were the major components. The antifungal activity of SAE and the three main components against Penicillium roqueforti and Aspergillus niger were determined by using the Oxford cup method and the sesqui-dilution method. The inhibition zones were 9.88 mm and 15.09 mm, while the minimum inhibitory concentrations were 125.00 µL/mL and 31.25 µL/mL. Trans-anethole and estragole both showed antifungal activity against Penicillium roqueforti and Aspergillus niger, while linalool only showed antifungal activity against Aspergillus niger. Propidium iodide and fluorescein diacetate staining analysis, leakage of cellular components (nucleic acids and proteins) and rise in ergosterol content indicated that SAE disrupted the integrity and permeability of the cell membrane. Malondialdehyde was increased after SAE treatment, indicating that SAE caused lipid peroxidation in the cell membrane, further confirming that it disrupted the cell membrane. At the same time, SAE interacted with membrane proteins and altered their conformation, resulting in cell membrane dysfunction. Finally, the shelf life test showed that SAE extended the shelf life of the bread by up to 6 days. In general, this study highlights the antifungal effect of SAE against Penicillium roqueforti and Aspergillus niger, which indicated that SAE can be used as an antifungal agent to extend the shelf life of bread.

Selenium Species and Fractions in the Rock-Soil-Plant Interface of Maize (Zea mays L.) Grown in a Natural Ultra-Rich Se Environment.

Selenium (Se) enrichments or deficiency in maize (Zea mays L.), one of the world's most important staple foods and livestock feeds, can significantly affect many people's diets, as Se is essential though harmful in excess. In particular, Se-rich maize seems to have been one of the factors that led to an outbreak of selenosis in the 1980s in Naore Valley in Ziyang County, China. Thus, this region's geological and pedological enrichment offers some insight into the behavior of Se in naturally Se-rich crops. This study examined total Se and Se species in the grains, leaves, stalks, and roots of 11 maize plant samples, Se fractions of soils around the rhizosphere, and representative parent rock materials from Naore Valley. The results showed that total Se concentrations in the collected samples were observed in descending order of soil > leaf > root > grain > stalk. The predominant Se species detected in maize plants was SeMet. Inorganic Se forms, mainly Se(VI), decreased from root to grain, and were possibly assimilated into organic forms. Se(IV) was barely present. The natural increases of Se concentration in soils mainly affected leaf and root dry-weight biomasses of maize. In addition, Se distribution in soils markedly correlated with the weathered Se-rich bedrocks. The analyzed soils had lower Se bioavailability than rocks, with Se accumulated predominantly as recalcitrant residual Se. Thus, the maize plants grown in these natural Se-rich soils may uptake Se mainly from the oxidation and leaching of the remaining organic-sulfide-bound Se fractions. A viewpoint shift from natural Se-rich soils as menaces to possibilities for growing Se-rich agricultural products is also discussed in this study.

Iron plaque effects on selenium and cadmium stabilization in Cd-contaminated seleniferous rice seedlings.

Dietary intake of selenium (Se)-enriched rice has benefit for avoiding Se-deficient disease, but there is a risk of excessive cadmium (Cd) intake. Through hydroponic culture and adsorption-desorption experiments, this paper focused on Se and Cd uptake in rice seedlings associated with the interactive effects of Se (Se4+ or Se6+), Cd, and iron (Fe) plaque. The formation of Fe plaque was promoted by Fe2+ and inhibited by Cd but not related with Se species. Shoot Se (Se4+ or Se6+) uptake was not affected by Fe plaque in most treatments, except that shoot Se concentrations were decreased by Fe plaque when Se4+ and Cd co-exposure. Shoot Cd concentrations were always inhibited by Fe plaque, regardless of Se species. Inhibiting Cd adsorption onto root surface (Se4+  + Cd) or increased Cd retention in Fe plaque (Se6+  + Cd) is an important mechanism for Fe plaque to reduce Cd uptake by rice. However, we found that DCB Cd concentrations (Cd adsorbed by Fe plaque) were not always positively correlated with Fe plaque amounts and always negatively correlated with the distribution ratios of Cd mass in root to that in Fe plaque (abbreviated as DRCMRF; r = - 0.942**); meanwhile, with the increase of DCB Fe concentration, the directions of variations of DCB Cd concentration and DRCMRF were affected by Se species. It indicated that the root system is also an important factor to affect DCB Cd concentration and inhibit Cd uptake, which is mediated by Se species. This paper provides a new understanding of Fe plaque-mediated interactive effect of Se and Cd uptakes in rice, which is beneficial for the remediation of Cd-contaminated and Cd-contaminated seleniferous areas.

Phosphorus sorption capacity of various iron-organic matter associations in peat soils.

This study was carried out to evaluate the contribution of different types of iron-organic matter associations (Fe-OM) to the phosphorus sorption capacity of peatland. Humic substance (HS) and particulate organic matter (POM) were isolated from peat soils, and different types of iron-organic matter associations (Fe-HS and Fe-POM) were prepared. Then, isothermal adsorption experiments were carried out on the synthesized Fe-OM and iron-contained peat soils. The morphology structure of Fe-HS associations is amorphous like that of ferrihydrite. The theoretical maximum adsorption capacity (Qmax) of Fe-HS associations can reach 36.90 mg/g, which is approximately two times higher than that of ferrihydrite (19.23 mg/g) and ten times higher than that of hematite (3.26 mg/g) and goethite (2.08 mg/g). Both peat soils and POM can strongly complex ferric ions, resulting in improved phosphorus sorption capacity. The Qmax of original peat soil and POM is 2.83 mg/g and 4.31 mg/g, which increased to 7.36 mg/g and 5.89 mg/g, respectively, after complexing ferric ions. Compared to inorganic Fe minerals, the associations of iron and organic matter (HS and POM) contribute more to the phosphorus retention ability of peat soils. However, the formation of Fe-OM associations could not fully explain why the addition of iron increases the phosphorus sorption capacity of peat soil by so much. Iron should also participate in other phosphorus retention processes, which need further exploration and research.

Synergistic inhibitory effect of selenium, iron, and humic acid on cadmium uptake in rice (Oryza sativa L.) seedlings in hydroponic culture.

Selenium (Se), iron (Fe), and humic acid (HA) are beneficial fertilizers that inhibit cadmium (Cd) uptake in crops and are crucial for agricultural yields as well as human health. However, the joined effect of Se, Fe, and HA on Cd uptake in rice are still poorly understood. Therefore, a hydroponic culture experiment was established to evaluate the combined effect of Se (Se4+ or Se6+), Fe, and HA on the biomass, Cd uptake, and Cd translocation of/in rice seedlings. Compared to Se6+ application, Se4+ application in most treatments resulted in lower Cd translocations from roots to shoots, leading to a significant decrease in shoot Cd concentrations. Compared to the treatments with Se4+ or Fe2+ application, joined application of Se4+ and Fe2+ inhibited Cd uptake in shoots by decreasing Cd adsorption onto (iron plaque) and uptake by roots, and alleviating Cd translocation from root to shoot. Compared to the treatments with Se6+ or Fe2+ application, joined application of Se6+ and Fe2+ inhibited Cd uptake in shoots by sequestering (retaining) Cd onto root surface (iron plaque). HA inhibited Cd uptake in all treatments by decreasing the bioavailability of Cd in the nutrient solution through complexation. The simultaneous application of Se, Fe, and HA decreased the shoot Cd concentrations the most, followed by the combined application of two fertilizers and their individual application; the mean shoot Cd concentration in the Fe-SeIV-HA2 treatment was the lowest among all the treatments, at only 11.39 % of those in the control treatments. The 3-way ANOVA results indicated that the Cd concentrations in shoots were significantly affected by Se, Fe, HA, and certain of their interactions (Fe×Se and Se×HA) (p< 0.05). The above findings suggest that the joined application of Se, Fe, and HA ameliorated Cd uptake mainly by inhibiting Cd adsorption onto (iron plaque) and uptake by roots and the translocation from roots to shoots (Fe×Se4+), retaining (sequestering) Cd in iron plaque (Fe×Se6+), and decreasing Cd availability in nutrient solution (HA).

Prolonged Sinus Pauses upon Termination of Paroxysmal Atrial Fibrillation: Abnormal Right Atrial Electrophysiologic and Electroanatomic Findings.

The efficacy of pulmonary vein antral isolation for patients with prolonged sinus pauses (PSP) on termination of atrial fibrillation has been reported. We studied the right atrial (RA) electrophysiologic and electroanatomic characteristics in such patients. Forty patients underwent electroanatomic mapping of the RA: 13 had PSP (group A), 13 had no PSP (group B), and 14 had paroxysmal supraventricular tachycardia (control group C). Group A had longer P-wave durations in lead II than did groups B and C (115.5 ± 15.4 vs 99.5 ± 10.9 vs 96.5 ± 10.4 ms; P=0.001), and RA activation times (106.8 ± 13.8 vs 99 ± 8.7 vs 94.5 ± 9.1 s; P=0.02). Group A's PP intervals were longer during adenosine triphosphate testing before ablation (4.6 ± 2.3 vs 1.7 ± 0.6 vs 1.5 ± 1 s; P <0.001) and after ablation (4.7 ± 2.5 vs 2.2 ± 1.4 vs 1.6 ± 0.8 s; P <0.001), and group A had more complex electrograms (11.4% ± 5.4% vs 9.3% ± 1.6% vs 5.8% ± 1.6%; P <0.001). Compared with group C, group A had significantly longer corrected sinus node recovery times at a 400-ms pacing cycle length after ablation, larger RA volumes (100.1 ± 23.1 vs 83 ± 22.1 mL; P=0.04), and lower conduction velocities in the high posterior (0.87 ± 0.13 vs 1.02 ± 0.21 mm/ms; P=0.02) and high lateral RA (0.89 ± 0.2 vs 1.1 ± 0.35 mm/ms; P=0.04). We found that patients with PSP upon termination of atrial fibrillation have RA electrophysiologic and electroanatomic abnormalities that warrant post-ablation monitoring.

Uranium(VI) reduction by nanoscale zero-valent iron in anoxic batch systems: the role of Fe(II) and Fe(III).

The role of Fe(II) and Fe(III) in U(VI) reduction by nanoscale zerovalent iron (nanoFe0) was investigated using two iron chelators 1,10-phenanthroline and triethanolamine (TEA) under a CO2-free anoxic condition. The results showed that U(VI) reduction was strongly inhibited by 1,10-phenanthroline and TEA in a pH range from 6.9 to 9.0. For instance, at pH 6.9 the observed U(VI) reduction rates decreased by 81% and 82% in the presence of 1,10-phenanthroline and TEA, respectively. The inhibition was attributed to the formation of stable complexes between 1,10-phenanthroline and Fe(II) or TEA and Fe(III). In the absence of iron chelators, U(VI) reduction can be enhanced by surface-bound Fe(II) on nanoFe0. Our results suggested that Fe(III) and Fe(II) possibly acted as an electron shuttle to ferry the electrons from nanoFe0 to U(VI), therefore a combined system with Fe(II), Fe(III) and nanoFe0 could facilitate U(VI) reductive immobilization in the contaminated groundwater.

Uranium(VI) removal by nanoscale zerovalent iron in anoxic batch systems.

This study investigated the influences of pH, bicarbonate, and calcium on U(VI) removal and reduction by synthetic nanoscale zerovalent iron (nanoFe(0)) particles under anoxic conditions. The results showed that the rates of U(VI) removal and reduction by nanoFe(0) varied significantly with pH and concentrations of bicarbonate and/or calcium. For instance, at pH 6.92 the pseudo-first-order rate constants of U(VI) removal decreased by 78.5% and 81.3%, and U(VI) reduction decreased by 90.3% and 89.3%, when bicarbonate and calcium concentrations were increased from 0 to 1 mM, respectively. X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of UO(2) and iron (hydr)oxides as a result of the redox interactions between U(VI) and nanoFe(0). The study demonstrated the potential of using nanoFe(0) for U(VI)-contaminated site remediation and highlighted the impacts of pH, bicarbonate, and calcium on the U(VI) removal and reduction processes.

Geological emission of methane from the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China.

A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/C/MS) together, the 13C/12C ratios of methane in the flux chambers were measured. The results demonstrated that methane gases were liable to migrate from deep oil/gas reservoir to the surface through microseepage and pervasion, and that a part of the migrated methane that remained unoxidized could emit into the atmosphere. Methane emission rates varied less in the oil/gas field because the whole region was homogeneous in geology and geography, with a standard deviation of less than 0.02 mg/(m2 x h). These were the differences in methane emission flux in the day and at night in the oil/gas field. The maximum methane emission flux reached 0.15 mg/(m2 x h) at 5:00-6:00 early in the morning, and then decreased gradually. The minimum was shown 0.10 mg/(m2 x h) at 17:00-18:00 in the afternoon, and then increased gradually. The daily methane released flux of the study area was 2.89 mg/(m2 x d), with a standard deviation of 0.43 mg/(m2 x d), using the average methane flux of every hour in a day for all chambers. delta13C of methane increased with the increase of methane concentration in the flux chambers, further indicating that the pyrogenetic origin of methane was come from deep oil/gas reservoirs.