Flooding soil with biogas slurry suppresses root-knot nematodes and alters soil nematode communities.

Root-knot nematodes (RKNs) pose a serious threat to crop production. Flooding soil with biogas slurry, combined with soil heating before crop planting, has the potential for RKN disease suppression. However, the actual effect of this method has not been verified under field conditions. Here, we present the results of a two-year field experiment in a greenhouse demonstrating the control effect on RKN disease and plant growth using this method, as well as its influence on the soil nematode community. Four treatments were set: untreated control (CK), local control method for RKN (CC), soil flooded with 70 % biogas slurry (BS70), and soil flooded with undiluted biogas slurry (BS100). In the first year, all three RKN control treatments significantly reduced the root-knot index (p < 0.05). In the next year, only BS70 and BS100 still presented significantly suppressed effects (p < 0.05), and it was more obvious under BS70 with a relative control effect of 74.6 %. In the first year, BS70 and BS100 significantly inhibited the plant height of watermelon (p < 0.05). In the next year, however, all three RKN control treatments promoted the growth of watermelon, and their stem diameter was significantly greater than that of CK. The application of biogas slurry (BS70 and BS100) significantly increased nematode richness and the Shannon index in the second year (p < 0.05). However, the structure index showed no significant difference among treatments (p > 0.05), indicating that biogas slurry application did not increase the soil food web complex. Principal component analysis showed that the application of biogas slurry changed the nematode community, especially under BS70, which presented a more lasting influence. The high-level input of biogas slurry also caused soil NH4+-N and heavy-metal and arsenic accumulation in the first year, but these soil-pollution risks disappeared in the second year.

Plant and microbial response in constructed wetland treating tetracycline antibiotic polluted water: Evaluating the effects of microplastic size and concentration.

Microplastics (MPs) and antibiotics are novel water pollutants that have attracted increasing attention. Constructed wetlands (CWs) are widely applied treating various types of polluted water. How these two new pollutants affect plants and microorganisms in CWs, especially deciphering the unknown roles of MPs size and concentration, is of great essential. Here, five CW treatments with submerged macrophyte Myriophyllum aquaticum were established to treat oxytetracycline (OTC) antibiotic-polluted water. The effects of polystyrene (PS) nanoplastics (NPs) (700 nm) and MPs (90-110 µm) on plant and microbial communities at 10 µg/L and 1 mg/L, respectively, were systematically evaluated. PS reduced the nitrogen and phosphorus removal efficiencies and inhibited OTC removal. Low doses (10 µg/L) of NPs and high doses (1 mg/L) of MPs had the greatest effects on plant and microbial responses. The overall effect of MPs was greater than that of NPs. Compared with high NPs concentration (1 mg/L), low concentrations (10 µg/L) had higher catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) content. However, the activity and content of MPs at low concentrations (10 µg/L) were lower than those at high concentrations (1 mg/L). The coexistence of OTC and MPs/NPs decreased the microbial diversity and abundance. Low doses of NPs and high doses of MPs decreased the relative abundance of Abditibacteriota, Deinococccota, and Zixibacteria. Redundancy and network analyses revealed a strong correlation between pollutant removal and plant and microbial responses. NH4+-N and OTC removal was positively and negatively correlated with CAT, SOD, and MDA content, respectively. MDA positively correlated to chlorophyll content, whereas SOD showed a negative correlation with Chloroflexi. This study highlighted the scale effect of MPs in wastewater treatment via CWs. It enhances our understanding of the response of plants and microorganisms to the remediation of water co-polluted with MPs and antibiotics.

Enhanced nitrogen removal via biochar-mediated nitrification, denitrification, and electron transfer in constructed wetland microcosms.

This study investigated the effect of biochar on real domestic wastewater treatment by constructed wetlands (CWs). To evaluate the role of biochar as a substrate and electron transfer medium on nitrogen transformation, three treatments of CW microcosms were established: conventional substrate (T1), biochar substrate (T2), and biochar-mediated electron transfer (T3). Nitrogen removal increased from 74% in T1 to 77.4% in T2 and 82.1% in T3. Nitrate generation increased in T2 (up to 2 mg/L) but decreased in T3 (lower than 0.8 mg/L), and the nitrification genes (amoA, Hao, and nxrA) in T2 and T3 increased by 132-164% and 129-217%, respectively, compared with T1 (1.56 × 104- 2.34 × 107 copies/g). The nitrifying Nitrosomonas, denitrifying Dechloromonas, and denitrification genes (narL, nirK, norC, and nosZ) in the anode and cathode of T3 were significantly higher than those of the other treatments (increased by 60-fold, 35-fold, and 19-38%). The genus Geobacter, related to electron transfer, increased in T3 (by 48-fold), and stable voltage (~150 mV) and power density (~9 uW/m2) were achieved. These results highlight the biochar-mediated enhancement of nitrogen removal in constructed wetlands via nitrification, denitrification, and electron transfer, and provide a promising approach for enhanced nitrogen removal by constructed wetland technology.

Evaluation of Nitrogen Fertilizer Fates and Related Environmental Risks for Main Cereals in China's Croplands from 2004 to 2018.

Assessment of the nitrogen (N) inputs and outputs in croplands would help effectively manage the distribution of N to improve crop growth and environmental sustainability. To better understand the N flow of the main cereal systems in China, soil N balance, N use efficiency (NUE), N losses and the potential environmental impacts of maize, wheat and rice cropping systems were estimated at the regional and national scales from 2004 to 2018. Nationally, the soil N balance (N inputs-N outputs) of maize, wheat, single rice and double rice decreased by 28.8%,13.3%, 30.8% and 34.1% from 2004-2008 to 2014-2018, equivalent to an average of 33.3 to 23.7 kg N ha-1, 82.4 to 71.4 kg N ha-1, 93.6 to 64.8 kg N ha-1 and 51.8 to 34.1 kg N ha-1, respectively. The highest soil N balance were observed in Southeast (SE) region for maize and double rice, North central (NC) region for wheat single rice and Northwest region for wheat, whereas Northeast (NE) region had the lowest N balance for all crops. The NUE increased from 49.8%, 41.2%, 49.7% and 53.7% in 2004-2008 to 54.8%, 45.9%, 55.5% and 56.5% in 2014-2018 for maize, wheat, single rice and double rice, respectively. The fertilizer N losses (i.e., N2O emission, NO emission, N2 emission, NH3 volatilization, N leaching and N runoff) were estimated as 43.7%, 38.3%, 40.2% and 36.6% of the total N inputs for maize, wheat, single rice and double rice, respectively in 2014-2018. Additionally, the highest global warming potential and acidification effects were found in NE and NC regions for maize, NC region for wheat, the middle and lower reaches of Yangtze River for single rice and SE region for double rice, respectively. The highest risk of water contamination by N leaching and surface runoff was observed in NC region for all crops mainly due to high N fertilizer input. Furthermore, the dynamics of N balance for all crops were closely tied with grain yields, except for single rice, the N balance of which was mainly correlated with N fertilizer input. Our results could help researchers and policy makers effectively establish optimized fertilization strategies and adjust the regional allocation of grain cropping areas in response to environmental risks and climate change caused by food crop cultivation in China.

Soil bacterial community and metabolism showed a more sensitive response to PBAT biodegradable mulch residues than that of LDPE mulch residues.

Biodegradable mulch film (BDM) is considered as an environmentally sustainable alternative to low density polyethylene (LDPE) mulch film. However, the low degradation rate of BDM resulted in residues in soil after service period which were similar to LDPE mulch film. Distinguishing the differential responses of crop growth, soil bacteria and metabolism to residues of BDM and LDPE mulch films is favourable for comparing the environmental toxicities of the two materials. The results indicated that emergence rate and yield of Chinese cabbage (Brassica campestris L. ssp. chinensis Makino) were significantly inhibited by two types mulch residues. BDM residues significantly decreased bacterial diversity by 1.2-2.3% through the enrichment of dominant phyla and inhibition of inferior phyla, while LDPE mulch residues not. The effects of BDM residues on soil metabolite spectrum were stronger than LDPE mulch residues with significant increase (3.9% 5.8%) in the abundance of total metabolites. Besides the pathways of metabolism, organismal systems, environmental information processing influenced by LDPE mulch resides, differential pathways including human diseases and cellular processes were also determined in soil with BDM residues. According to all the results of the present study, prior to the promotion of BDM, its influences on soil safety must be carefully investigated through critical and systematic research.

Dynamical and noninvasive monitoring of curcumin effect on the changes in the viscoelasticity of human breast cancer cells: A novel model to assess cell apoptosis.

A real-time quartz crystal microbalance (QCM) cytosensor was first developed for dynamical and noninvasive monitoring of cell viscoelasticity for evaluation of apoptosis degree. In this work, human breast cancer cells MCF-7 and MDA-MB-231 were employed as cell model and respectively captured on the surface of QCM electrode modified with mercaptosuccinic acid and poly-l-lysine. Cell viscoelasticity was measured dynamically by real-time monitoring energy dissipation with QCM, and the dynamic diagram of the energy dissipation of MDA-MB-231 cells treated with curcumin was first obtained. The results displayed that the changes of energy dissipation in MDA-MB-231 cells and MCF-7 cells were 8.81 × 10-6 and 5.29 × 10-6, particularly due to the difference in cell viscoelasticity. Furthermore, curcumin was used to induce cell apoptosis and suppress energy dissipation of MDA-MB-231 cells. Combining apoptosis assay with QCM measurement, the results revealed good linear relationship between cell viscoelasticity inhibition and apoptosis rate with correlation coefficient R = 0.9908. The QCM cytosensor could rapidly, accurately, dynamically, and noninvasively monitor the changes of cell viscoelasticity for evaluation of apoptosis degree in MDA-MB-231 cells. The study established a new model for cell apoptosis assessment, facilitating understanding of the mechanisms of cell apoptosis on the aspect of mechanical properties.

Plastic pollution in croplands threatens long-term food security.

Plastic pollution is a global concern given its prevalence in aquatic and terrestrial ecosystems. Studies have been conducted on the distribution and impact of plastic pollution in marine ecosystems, but little is known on terrestrial ecosystems. Plastic mulch has been widely used to increase crop yields worldwide, yet the impact of plastic residues in cropland soils to soil health and crop production in the long term remained unclear. In this paper, using a global meta-analysis, we found that the use of plastic mulch can indeed increase crop yields on average by 25%-42% in the immediate season due to the increase of soil temperature (+8%) and moisture (+17%). However, the unabated accumulation of film residues in the field negatively impacts its physicochemical properties linked to healthy soil and threatens food production in the long term. It has multiple negative impacts on plant growth including crop yield (at the mean rate of -3% for every additional 100 kg/ha of film residue), plant height (-2%) and root weight (-5%), and soil properties including soil water evaporation capacity (-2%), soil water infiltration rate (-8%), soil organic matter (-0.8%) and soil available phosphorus (-5%) based on meta-regression. Using a nationwide field survey of China, the largest user of plastic mulch worldwide, we found that plastic residue accumulation in cropland soils has reached 550,800 tonnes, with an estimated 6%-10% reduction in cotton yield in some polluted sites based on current level of plastic residue content. Immediate actions should be taken to ensure the recovery of plastic film mulch and limit further increase in film residue loading to maintain the sustainability of these croplands.

Comparative anti-arthritic investigation of iridoid glycosides and crocetin derivatives from Gardenia jasminoides Ellis in Freund's complete adjuvant-induced arthritis in rats.

BACKGROUND: Discovering novel compounds with higher activities is a key aim of natural products research. Gardenia jasminoides Ellis is a herb with anti-inflammatory properties. Iridoid glycosides (mainly geniposide) and crocetin derivatives (crocins) are the two major active constituents in this herb and are considered its active ingredients. However, which components are responsible for the anti-inflammatory properties of gardenia have remained to be investigated. PURPOSE: Here, we prepared total iridoid glycocides (TIG) and total crocins (TC) from G. jasminoides Ellis, determined their main chemical constituents, and performed animal studies to evaluate their anti-adjuvant arthritis activities, thus, proposing a reasonable mechenism to explain the anti-inflammatory activities of the active components in this herbal remedy. STUDY DESIGN: TIG and TC were prepared by using HPD-100 macroporous resin, and characterized by UHPLC-DAD-MS and UV-Vis spectrophotometer. Then, freund's complete adjuvant-injected rats underwent drug treatments with TIG (160 mg/kg) and TC (160 mg/kg) for 14 days, and their ankle diameters were measured. Moreover, X-ray radiographs of the adjuvant injected hind paws were evaluated. Finally, histopathological examinations of the ankle joints, spleens and thymus were carried out to evaluate inflammatory reactions, and immunohistochemical measurements were conducted to evaluate TNF-α and TGF-ß1 expression in the ankle joint of the rats. RESULTS: The chemical composition determination of the current study showed that TIG was mainly composed of geniposide and TC was a fraction predominantly with crocin-1, crocin-2 and crocin-3. Calculation of results showed that TIG and TC contained 58.2% total iridoid glycosides and 54.7% total crocins, respectively. Our study suggested TIG and TC treatments markedly decreased paw swelling and ankle diameters of AA rats (both p < 0.05). The radiological analysis showed that administration of TIG and TC ameliorated bone destruction, and reduced the radiological bone destruction scores (TIG p < 0.05, TC p>0.05). Moreover, data from histological assessment demonstrated considerable mitigation of inflammation in the joints (both p < 0.01), spleen and thymus of AA rats treated with TIG and TC. TNF-α and TGF-ß1 protein expression according to immunohistochemistry staining also supported the anti-arthritis activities of TIG and TC (TNF-α: TIG p < 0.01 and TC p < 0.05, TGF-ß1: TIG p < 0.01 and TC p>0.05). CONCLUSION: In the current study, fractionation of gardenia prior to further in vivo investigation has for the first time provided reasonable explanation for the anti-inflammatory activity of this herbal remedy. Our study showed that both TIG and TC from gardenia have anti-inflammatory properties. Overall, these experimental findings suggest that gardenia could be regarded as a potential therapeutic target for arthritis. However, as geniposide has a higher content than crocins in this herbal drug, TIG (mainly geniposide) seems to be primarily responsible for the anti-inflammatory properties of gardenia. Taken together, this maiden attempt demonstrated that TIG (mainly geniposide) is more important in evaluating the anti-inflammatory activity of G. jasminoides Ellis.

Separation and purification of five alkaloids from Aconitum duclouxii by counter-current chromatography.

C19 -diterpenoid alkaloids are the main components of Aconitum duclouxii Levl. The process of separation and purification of these compounds in previous studies was tedious and time consuming, requiring multiple chromatographic steps, thus resulted in low recovery and high cost. In the present work, five C19 -diterpenoid alkaloids, namely, benzoylaconine (1), N-deethylaconitine (2), aconitine (3), deoxyaconitine (4), and ducloudine A (5), were efficiently prepared from A. duclouxii Levl (Aconitum L.) by ethyl acetate extraction followed with counter-current chromatography. In the process of separation, the critical conditions of counter-current chromatography were optimized. The two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water/NH3 ·H2 O (25%) (1:1:1:1:0.1, v/v) was selected and 148.2 mg of 1, 24.1 mg of 2, 250.6 mg of 3, 73.9 mg of 4, and 31.4 mg of 5 were obtained from 1 g total Aconitum alkaloids extract, respectively, in a single run within 4 h. Their purities were found to be 98.4, 97.2, 98.2, 96.8, and 96.6%, respectively, by ultra-high performance liquid chromatography analysis. The presented separation and purification method was simple, fast, and efficient, and the obtained highly pure alkaloids are suitable for biochemical and toxicological investigation.

Systematic separation and purification of iridoid glycosides and crocetin derivatives from Gardenia jasminoides Ellis by high-speed counter-current chromatography.

INTRODUCTION: Iridoid glycosides and crocetin derivatives are the main bioactive components of Gardenia. The processes of separation of these compounds reported in much of the literature are tedious, time consuming and require multiple chromatographic steps, which results in lower recovery and higher costs. OBJECTIVE: To develop a high-speed counter-current chromatography (HSCCC) method for the systematic separation and purification of iridoid glycosides and crocetin derivatives on a preparative scale from Gardenia. METHODS: After fractionation using HPD100 column chromatography, n-butanol:ethanol:water (10:1:10, v/v) was selected to purify gardenoside, 6ß-hydroxy geniposide and geniposidic acid from fraction A; ethyl acetate:n-butanol:water (2:1.5:3, v/v) was used to isolate geniposide from fraction B; crocin-1, crocin-2, crocin-3 and crocin-4 were purified by hexane:ethyl acetate:n-butanol:water (1:2:1:5, v/v) from fraction C. The head-to-tail elution mode was used with a flow rate of 8.0 mL/min and a rotary speed of 600 rpm. RESULTS: After HSCCC isolation, 151.1 mg of gardenoside, 52.2 mg of 6ß-hydroxy geniposide and 24.5 mg of geniposidic acid were obtained from 800 mg of fraction A; 587.2 mg of geniposide was obtained from 800 mg of Fraction B; 246.2 mg of crocin-1, 34.2 mg of crocin-2, 24.4 mg of crocin-3 and 24.7 mg of crocin-4 were obtained from 1000mg of fraction C. Their purities were found by UPLC analysis to be 91.7%, 93.4%, 92.5%, 98.2%, 94.1%, 96.3%, 94.1% and 98.9% respectively. CONCLUSION: The present results demonstrates that the main iridoid glycosides and crocetin derivatives in Gardenia can be obtained efficiently from extracts using HSCCC.

Separation and purification of 9,10-dihydrophenanthrenes and bibenzyls from Pholidota chinensis by high-speed countercurrent chromatography.

Stilbenoids are the main components of leaves and stems of Pholidota chinensis. In the present investigation, high-speed counter-current chromatography was used for the separation and purification of two classes of stilbenoids, namely, bibenzyls and 9,10-dihydrophenanthrenes, on a preparative scale from whole plants of P. chinensis with different solvent systems after silica gel column chromatography fractionation. n-Hexane/ethyl acetate/methanol/water (1.2:1:1:0.8, v/v/v/v) was selected as the optimum solvent system to purify 1-(3,4,5-trimethoxyphenyl)-1',2'-ethanediol (1), coelonin (2), 3,4'-dihydroxy-5,5'-dimethoxybibenzyl (3), and 2,​7-​dihydroxy-​3,​4,​6-​trimethoxy-​9,​10-​dihydrophenanthrene (4). While 2,7-dihydroxy-3,4,6-trimethoxy-​9,​10-​dihydrophenanthrene (5), batatasin III (6), orchinol (7), and 3'-O-methylbatatasin III (8) were purified by n-hexane/ethyl acetate/methanol/water (1.6:0.8:1.2:0.4, v/v/v/v). After the high-speed counter-current chromatography isolation procedure, the purity of all compounds was over 94% assayed by ultra high performance liquid chromatography. The chemical structure identification of all compounds was carried out by mass spectrometry and (1)H and (13)C NMR spectroscopy. To the best of our knowledge, the current investigation is the first study for the separation and purification of bibenzyls and 9,10-dihydrophenanthrenes by high-speed counter-current chromatography from natural resources.

Immunogenicity and immunoprotection of recombinant PEB1 in Campylobacter-jejuni-infected mice.

AIM: To construct a prokaryotic expression vector carrying Campylobacter jejuni peb1A gene and express it in Escherichia coli. Immunoreactivity and antigenicity of rPEB1 were evaluated. The ability of rPEB1 to induce antibody responses and protective efficacy was identified. METHODS: peb1A gene was amplified by PCR, target gene and prokaryotic expression plasmid pET28a (+) was digested with BamHI and XhoI, respectively. DNA was ligated with T4 DNA ligase to construct recombinant plasmid pET28a(+)-peb1A. The rPEB1 was expressed in E. coli BL21 (DE3) and identified by SDS-PAGE. BALB/c mice were immunized with rPEB1. ELISA was used to detect the specific antibody titer and MTT method was used to measure the stimulation index of spleen lymphocyte transformation. RESULTS: The recombinant plasmid pET28a (+)-peb1A was correctly constructed. The expression output of PEB1 protein in pET28a (+)-peb1A system was approximately 33% of total proteins in E. coli. The specific IgG antibody was detected in serum of BALB/c mice immunized with rPEB1 protein. Effective immunological protection with a lower sickness incidence and mortality was seen in the mice suffering from massive C. jejuni infection. CONCLUSION: rPEB1 protein is a valuable candidate for C. jejuni subunit vaccine.