Application of alkali-heated corncobs enhanced nitrogen removal and microbial diversity in constructed wetlands for treating low C/N ratio wastewater.

Lack of carbon source is the main limiting factor in the denitrification of low C/N ratio wastewater in the constructed wetlands (CWs). Agricultural waste has been considered as a supplementary carbon source but research is still limited. To solve this problem, ferric carbon (Fe-C) + zeolite, Fe-C + gravel, and gravel were used as substrates to build CWs in this experiment, aiming to investigate the effects of different carbon sources (rice straw, corncobs, alkali-heated corncobs) on nitrogen removal performance and microbial community structure in CWs for low C/N wastewater. The results demonstrated that the microbial community and effluent nitrogen concentration of CWs were mainly influenced by the carbon source rather than the substrate. Alkali-heated corncobs significantly enhanced the removal of NO2--N, NH4+-N, NO3-N, and TN. Carbon sources addition increased microbial diversity. Alkali-heated corncobs addition significantly increased the abundance of heterotrophic denitrifying bacteria (Proteobacteria and Bacteroidota). Furthermore, alkali-heated corncobs addition increased the copy number of nirS, nosZ, and nirK genes while greenhouse gas fluxes were lower than common corncobs. In summary, alkali-heated corncobs can be considered as an effective carbon source.

The removal of antibiotic resistant bacteria and antibiotic resistance genes by sulfidated nanoscale zero-valent iron activating periodate: Efficacy and mechanism.

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have drawn much more attention due to their high risk on human health and ecosystem. In this study, the performance of sulfidated nanoscale zero-valent iron (S-nZVI)/periodate (PI) system toward ARB inactivation and ARGs removal was systematically investigated. The S-nZVI/PI system could realize the complete inactivation of 1 × 108 CFU/mL kanamycin, ampicillin, and tetracycline-resistant E. coli HB101 within 40 min, meanwhile, possessed the ability to remove the intracellular ARGs (iARGs) (including aphA, tetA, and tnpA) carried by E. coli HB101. Specifically, the removal of aphA, tetA, and tnpA by S-nZVI/PI system after 40 min reaction was 0.31, 0.47, and 0.39 log10copies/mL, respectively. The reactive species attributed to the E. coli HB101 inactivation were HO• and O2•-, which could cause the destruction of E. coli HB101 morphology and enzyme system (such as superoxide dismutase and catalase), the loss of intracellular substances, and the damage of iARGs. Moreover, the influence of the dosage of PI and S-nZVI, the initial concentration of E. coli HB101, as well as the co-existing substance (such as HCO3-, NO3-, and humic acid (HA)) on the inactivation of E. coli HB101 and its corresponding iARGs removal was also conducted. It was found that the high dosage of PI and S-nZVI and the low concentration of E. coli HB101 could enhance the disinfection performance of S-nZVI/PI system. The presence of HCO3-, NO3-, and HA in S-nZVI/PI system showed inhibiting role on the inactivation of E. coli HB101 and its corresponding iARGs removal. Overall, this study demonstrates the superiority of S-nZVI/PI system toward ARB inactivation and ARGs removal.

[Chemical constituents of Osmanthus fragrans].

By Silica gel, Sephadex LH-20 and other materials for isolation and purification and by physicochemical methods and spectral analysis for structural identification, 32 compounds were isolated and identified from ethyl acetate portion of alcohol extract of the Osmanthus fragrans. Their structures were identified as boschniakinic acid (1), ursolaldehyde (2), augustic acid (3), arjunolic acid (4), 5-hydroxymethyl-2-furancarboxaldehyde (5), isoscutellarein (6), 6, 7-dihydroxycoumarin (7), 2α-hydroxy-oleanolic acid (8), quercetin-3-0-ß-D-glu-copyranoside (9), D-allito (10), 5, 4'-dihydroxy-7- methoxyflavone-3-0-ß-D-glucopyranoside (11), 5,7-dihydroxychromone (12), lupeol (13), naringenin (14), acetyloleanolic acid (15), chlorogenic acid (16), kaempferol-3-0-ß- D-glucopyranoside (17), oleanolic acid (18), kaempferol-3-0-ß-D-galactopyanoside (19), 3', 7-dihydroxy-4'-methoxyisoflavon (20), ergosta-4,6,8 (14), 22-tetraen-3-one (21), p-hydroxycinnamic acid (22), syringaresinol (23), 3,4-dihydroxyacetophenonel (24), ß-sitosterol (25), ethyl p-hydroxyphenylacetate (26), benzoic acid (27), caffeic acid (28), coelonin (29), p-hydorxy-phenylacetic acid (30), p-hydroxyacetophenone (31), and methyl-p-hydroxphenylacetate (32). Except for compounds 2, 4, 5, 8-11, 13, 15, 18, 20, 25, and 27, the rest were isolated from the Osmanthus fragrans for the first time.

Effects of crude oil and dispersed crude oil on the critical swimming speed of puffer fish, Takifugu rubripes.

In order to examine the effects of crude oil and dispersed crude oil (DCO) on the swimming ability of puffer fish, Takifugu rubripes, the critical swimming speeds (U crit) of fish exposed to different concentrations of water-soluble fraction (WSF) of crude oil and DCO solution were determined in a swimming flume. WSF and DCO significantly affected the U crit of puffer fish (p < 0.05). The U crit of puffer fish exposed to 136 mg L(-1) WSF and 56.4 mg L(-1) DCO decreased 48.7 % and 43.4 %, respectively. DCO was more toxic to puffer fish than WSF. These results suggested that crude oil and chemically dispersed oil could weaken the swimming ability of puffer fish.

[Chemical Constituents of Paris polyphylla var. chinensis Aerial Parts].

OBJECTIVE: To study the chemical constituents of aerial parts of Paris polyphylla var. chinensis . METHODS: Aerial parts of Paris polyphylla var. chinensis was extracted with 95% EtOH, and separated and purified by silica gel, RP 18 and Sephadex LH-20 col- umn chromatography. The structures were identified by spectroscopic analysis. RESULTS: A total of ten compounds were isolated and iden- tified as ß-sitosterol (1) ergosta-7, 22-dien-3-one (2), ß-ecdysone (3), kaempferol (4), daucosterol (5) luteolin (6) calonysterone (7), luteolin-7-O-glucoside (8), quercetin (9), and 3ß, 5α, 9α-trihydroxyergosta-7, 22-dien-6-one (10). CONCLUSION: Compounds 2,6 and 10 are isolated from Paris polyphylla var. chinensis for the first time.

[Chemical Constituents of Citrus medica Fruit].

OBJECTIVE: To study the chemical constituents of Citrus medica fruit. METHODS: The fruit of Citrus medica was extracted with 95% EtOH, and the compounds were separated and purified by silica gel, RP-18 and Sephadex LH-20 column chromatography. The structures were identified by spectroscopic analysis. RESULTS: A total of 16 compounds were isolated and identified, including methyl ferulic acid (1), dihydro-N-caffeoyltyramine (2) acacetin (3), ß-ecdysterone (4), (-)-balanophonin (5), p-methoxy cinnamic acid (6), umbelliferone (7), ferulic acid (8), pyrocatechualdehyde (9), diosmetin (10), 4-methoxy salicylic acid (1), ß-amyrin acetate (12), epigallocatechin (13), betulinic acid (14), lupeol (15) and nicotinamide (16). CONCLUSION: All the compounds are isolated from the fruit of Citrus medica for the first time.

[Chemical constituents of Osmanthus fragrans fruits].

By Silica gel, Sephadex LH-20 and other materials for isolation and purification and by physicochemical methods and spectral analysis for structural identification, 23 compounds were isolated and identified from ethyl acetate portion of alcohol extract solution of Osmanthus fragrans fruits. Their structures were identified as nicotinamide (1), D-allitol (2), 5-hydroxymethyl-2-furancarboxaldehyde (3), acetyloleanolic acid (4), benzoic acid (5), ergosta-7,22-dien-3-one (6), beta-sitosterol (7), borreriagenin (8), cerevistero (9), c-veratroylglycol (10), methyl-2-O-beta-glucopyranosylbenzoate (11), 3', 7-dihydroxy-4'-methoxyisoflavon (12), umbelliferone (13), caffeic acid methyl ester (14), oleanolic acid (15), (-) -chicanine (16), dillapiol (17), 3beta,5alpha, 9alpha-trihydroxyergosta-7-22-dien-6-one (18), 2alpha-hydroxy-oleanolic acid (19), betulinic acid (20), betulin (21), 3, 3'-bisdemethylpinoresinol (22), and lupeol (23). All compounds were isolated from the osmanthus fruit for the first time. Except for compounds 4, 7, 15, 19, 23, the rest ones were isolated from the this plant for the first time.

[Genetic diversity of Sabina vulgaris populations at different succession stages].

By means of random amplified polymorphic DNA markers, a molecular ecological study was made with Sabina vulgaris populations at 4 succession stages in Maowusu sandy grassland, aimed to reveal the relationships between molecular variation and succession stages. A total of 17 random primers were selected for amplification, and 190 repetitive loci were produced, of which, 173 were polymorphic. The data were analyzed by POPGENE 3. 2 Version 1. 31. The results showed that the genetic diversity of S. vulgaris populations was high, and changed with succession stages. The percentage of polymorphic loci in each S. vulgaris population ranged from 64.21% to 74.63%, with the highest in early succession stage Artemisia ordosica + S. vulgaris on semi-fixed sand dunes, and the lowest in sub-climax stage S. vulgaris on fixed dunes. The genetic differentiation among the populations was small (G(st) = 0.1761), and 82.39% of it was within the populations. Cluster analysis demonstrated that the populations at similar succession stage clustered together, suggesting that the genetic differentiation was closely related to succession stage. The genetic diversity indicated by Nei index ranged in 0. 2163 -0. 2564, and the gene flow (N(m) *) was 2.7972, indicating that more gene exchange occurred within the populations, which prevented the genetic differentiation among the populations at different succession stages.