Nitrogen (N) "supplementation, slow release, and retention" strategy improves N use efficiency via the synergistic effect of biochar, nitrogen-fixing bacteria, and dicyandiamide

Irrational nitrogen (N) fertilizer management and application practices have led to a range of ecological and environmental problems that seriously threaten food security. In this study, an effective N fertilizer management strategy was established for improving N fertilizer utilization efficiency (NUE). Biochar, N2-fixing bacteria (Enterobacter cloacae), and a nitrification inhibitor (dicyandiamide, DCD) were simultaneously added to the soil during maize cultivation. The goal was to increase soil ammonium nitrogen content and NUE by regulating the relative abundance, enzyme activity, and functional gene expression of N conversion-related soil microbes. Biochar combined with E. cloacae and DCD significantly increased soil N content, and the NUE reached 46.69 %. The relative abundance of Burkholderia and Bradyrhizobium and the activity of nitrogenase increased significantly during biological N2 fixation. Further, the abundance of the nifH gene was significantly up-regulated. The relative abundance of Sphingomonas, Pseudomonas, Nitrospira, and Castellaniella and the activities of ammonia monooxygenase and nitrate reductase decreased significantly during nitrification and denitrification. Moreover, the abundance of the genes amoA and narG was significantly down-regulated. Correlation analyses showed that the increase in soil N2 fixation and the suppression of nitrification and denitrification reactions were the key contributors to the increase in soil N content and NUE. Biochar combined with E. cloacae and DCD synergistically enabled the supplementation, slow release, and retention of N, thus providing adequate N for maize growth. Thus, the combination of biochar, E. cloacae, and DCD is effective for mitigating the irrational application of N fertilizers and reducing N pollution.

Study on the effectiveness and mechanism of a sustainable dual slow-release model to improve N utilization efficiency and reduce N pollution in black soil

Long-term intensive cultivation has led to serious N loss and low N fertilizer utilization efficiency (NUE) in black soil areas. The lost N is not only a waste of resources but also a serious pollution threat to the environment, leading to the decline in water quality and food safety and the greenhouse effect. In the present study, a stable dual slow-release model, CPCS-Urea, was prepared by in situ polymerization using nitrapyrin, urea and melamine-formaldehyde resin as raw materials. The effect of the dual slow-release model was systematically evaluated using two consecutive years of field experiments. Five treatments were established in the field experiment: no N fertilizer (N0), urea (N180), 1 % CPEC-Urea, 0.5 % CPCS-Urea, and 1 % CPCS-Urea. The results showed that the new dual slow-release CPCS-Urea model outperformed both the use of urea and the traditional slow-release CPEC-Urea model in reducing N losses and improving NUE. The application of CPCS-Urea reduced nitrate (NO3-) leaching by 28.2 %-47.2 % and N2O emissions by 36.5 %-42.4 % and increased NUE by 20.7 %-28.5 % compared to urea application. The CPCS-Urea model modulated the activity of ammonia-oxidizing bacteria (AOB) and dissimilatory nitrate reduction to ammonium (DNRA) bacteria in soil, showing a significant decrease in AOB activity and an increase in DNRA activity. This results in a lower soil NO3--N yield and a 53.1 %-72.0 % increase in NH4+-N content, providing sufficient N for the entire growth and development cycle of maize. In short, the dual slow-release CPCS-Urea model has great application prospects for promoting agricultural development in black soil areas.

The combined action of biochar and nitrogen-fixing bacteria on microbial and enzymatic activities of soil N cycling

This study aims to investigate the positive effects of the combined use of Enterobacter cloacae and biochar on improving nitrogen (N) utilization. The greenhouse pots experimental results showed the synergy of biochar and E. cloacae increased soil total N content and plant N uptake by 33.54% and 15.1%, respectively. Soil nitrogenase (NIT) activity increased by 253.02%. Ammonia monooxygenase (AMO) and nitrate reductase (NR) activity associated with nitrification and denitrification decreased by 10.94% and 29.09%, respectively. The relative abundance of N fixing microorganisms like Burkholderia and Bradyrhizobium significantly increased. Sphingomonas and Ottowia, two bacteria involved in the nitrification and denitrification processes, were found to be in lower numbers. The E. cloacae's ability to fix N₂ and promote the growth of plants allow the retention of N in soil and make more N available for plant development. Biochar served as a reservoir of N for plants by adsorbing N from the soil and providing a shelter for E. cloacae. Thus, biochar and E. cloacae form a synergy for the management of agricultural N and the mitigation of negative impacts of pollution caused by excessive use of N fertilizer.

Enhancing N uptake and reducing N pollution via green, sustainable N fixation-release model

The overuse of N fertilizers has caused serious environmental problems (e.g., soil acidification, excessive N₂O in the air, and groundwater contamination) and poses a serious threat to human health. Improving N fertilizer utilization efficiency and plant uptake is an alternative for N fertilizers overuses. Enterobacter cloacae is an opportunistic pathogen, also used as plant growth-promoting rhizobacteria (PGPR), has been widely presented in the fields of bioremediation and bioprotection. Here we developed a new N fixation-release model by combining biochar with E. cloacae. The efficiency of the model was evaluated using a greenhouse pot experiment with maize (Zea mays L.) as the test crop. The results showed that biochar combined with E. cloacae significantly increased the N content. The application of biochar combined with E. cloacae increased total N in soil by 33% compared with that of N fertilizers application. The N-uptake and utilization efficiency (NUE) in plant was increased 17.03% and 14.18%, respectively. The activities of urease, dehydrogenase and fluorescein diacetate hydrolase (FDA) was improved, the catalase (CAT) activity decreased. Analysis of the microbial community diversity revealed the abundance of Proteobacteria, Actinobacteria, Firmicutes, and Gemmatimonadetes were significantly improved. The mechanism under the model is that E. cloacae acted as N-fixation by capturing N₂ from air. Biochar served as carrier, supporting better living environment for E. cloacae, also as adsorbent adsorbing N from fertilizer and from fixed N by E. cloacae, the adsorption in turn slower the N release. Altogether, the model promotes N utilization by plants, improves the soil environment, and reduces N pollution.

Removal of dye pollution by an oxidase derived from mutagenesis of the Deuteromycete Myrothecium with high potential in industrial applications

It is estimated that over 700,000 tons of synthetic dyes are produced annually, 15% of which are emitted as effluents. These highly stable dyes enter the world water ecosystems and stay in the environment, and eventually cause adverse impacts to the environment. Current wastewater treatment methods, such as filtration, coagulation, and chemical oxidation, have sideeffects, including toxic residue formation, membrane fouling, bioaccumulation, and secondary pollutant formation. Given the issues mentioned, it is necessary to study how to improve the degradation of synthetic dye with a cost-effective and ecofriendly approach. Natural oxidation provides a greener option. Recently, Deuteromycetes fungus Myrothecium verrucaria G-1 (M. verrucaria G-1) has shown great potential in producing high level of dye oxidase. This study aims to generate a dye oxidase hyperproducer, 3H6 from M. verrucaria G-1 by using atmospheric and room temperature plasma (ARTP) coupled with ultraviolet (UV) irradiation. This method increases oxidase production by nearly 106.15%. After a simple precipitation and dialysis, this mutant oxidase increases by 1.97-fold in a specific activity with dye degradation rates at 70% for Mmethylene blue (MB) and 85% for Congo red (CR). It is found that the genetic stability of 3H6 remains active for ten generations. The size of oxidase is 65 kDa, and optimum temperature for reaction is 30 °C with 4.5 pH. This study presents that the first combined mutagenesis approach by ARPT-UV on fungus species generates an impressive increment of acid dye oxidases production. As such, this method presents a cost-effective alternative to mitigate hazardous dye pollution.

Physiological effects of transport duration on stress biomarkers and meat quality of medium-growing Yellow broiler chickens

Pre-slaughter transport exerts negative effects on broilers' welfare, meat yield, and meat quality, but little is known about the effect of transport on medium-growing broiler chickens. This study aimed at evaluating the effects of different durations of transport (0, 0.5, 1, 2, and 3h) on stress biomarkers and meat quality of medium-growing Yellow-feathered broiler chickens. One hundred and eighty Chinese Yellow-feathered broilers aged 75days (marketing age), of 2.02kg average BW, were allotted into five groups; each group contained six replicates (six birds/replicate (crate)). Each crate with dimensions 74×55×27cm (length × width × height) was loaded with six birds, that is, 30kg live BW/m² crate. The tested transport durations increased BW loss (linear, P<0.01), plasma concentrations of ACTH (linear, P<0.10), cortisol and corticosterone (quadratic, P<0.05), and activity of glutathione peroxidase (linear, P<0.05), whereas plasma glucose was not affected. In breast muscle, contents of glycogen, lactic acid, malondialdehyde, and reduced glutathione were not affected (P>0.05), but total antioxidant capacity decreased (linear, P<0.01). The drip loss of breast muscle increased (linear, P<0.01), whereas shear force, pH at 24h postmortem, and breast meat color lightness (L*), redness (a*), and yellowness (b*) scores were not affected. In conclusion, the tested transport durations (from 0.5 to 3h) increased BW loss and some plasma stress biomarkers in 75-day-old Yellow-feathered broiler chickens, but the effect on meat quality attributes was minor.

Innovative hydrolysis of corn stover biowaste by modified magnetite laccase immobilized nanoparticles

Intensive studies have been performed on the improvement of bioethanol production by transformation of lignocellulose biomass. In this study, the digestibility of corn stover was dramatically improved by using laccase immobilized on Cu²⁺ modified recyclable magnetite nanoparticles, Fe₃O₄-NH₂. After digestion, the laccase was efficiently separated from slurry. The degradation rate of lignin reached 40.76%, and the subsequent cellulose conversion rate 38.37% for 72 h at 35 °C with cellulase at 50 U g^-1 of corn stover. Compared to those of free and inactivated mode, the immobilized laccase pre-treatment increased subsequent cellulose conversion rates by 23.98% and 23.34%, respectively. Moreover, the reusability of immobilized laccase activity remained 50% after 6 cycles. The storage and thermal stability of the fixed laccase enhanced by 70% and 24.1% compared to those of free laccase at 65 °C, pH 4.5, respectively. At pH 10.5, it exhibited 16.3% more activities than its free mode at 35 °C. Our study provides a new avenue for improving the production of bioethanol with immobilized laccase for delignification using corn stover as the starting material.

Optimization of Dietary Zinc Requirement for Broiler Breeder Hens of Chinese Yellow-Feathered Chicken

Simple Summary

China is the second-largest global producer of chicken meat, almost half of which is from the Chinese yellow-feathered breed; a systematic program has been initiated to improve its feeding standards. This study evaluated the optimal requirement of dietary zinc for maximal egg production, egg quality, tibial quality, and antioxidant indices of laying broiler breeders. The results revealed several beneficial effects of supplementary zinc on egg production, feed conversion ratio, yolk zinc content, tibial quality and the antioxidant indices in the serum, liver and ovary. The optimal zinc requirement was estimated based on a regression model.

Abstract

This study aimed to establish the optimal dietary zinc requirement of Chinese yellow-feathered Lingnan broiler breeders. A total of 576 breeder hens aged 58 weeks were randomly assigned to six treatments, each with 6 replicates of 16 birds (n = 96/treatment). The hens were fed either a basal diet (22.81 mg/kg Zn) or the same basal diet supplemented with additional 24, 48, 72, 96, and 120 mg Zn/kg up to 65 weeks of age. Compared to the results of birds fed the basal diet (22.81 mg Zn/kg), the dietary supplementation with additional Zn (mg/kg) showed higher egg laying rate (at 48–120 mg), EM (at 96 mg/kg), yolk Zn content (at 24–120 mg/kg), fertility (at 48–120 mg/kg), hatchability (at 48–96 mg/kg), tibial breaking strength (at 24–48 mg/kg), tibial ash content (at 48 mg/kg), serum CuZnSOD activity (at 72 mg/kg) and T-AOC (at 48 mg/kg), and ovarian CuZnSOD and GSH-Px activities (at 96–120 mg/kg), and lower FCR (at 96 mg/kg). The regression model showed that the optimal supplemental Zn for maximal egg laying rate, yolk Zn content, fertility, and hatchability of Chinese yellow-feathered broiler breeders aged 58 to 65 weeks were 71.09, 92.34, 94.44 and 98.65 mg/kg diet, respectively.

Impacts of Graded Levels of Metabolizable Energy on Growth Performance and Carcass Characteristics of Slow-Growing Yellow-Feathered Male Chickens

A dose-response study was conducted to investigate the metabolizable energy (ME) requirement for Lingnan chickens from 9 to 15 weeks of age. One thousand two hundred 8-week-old slow-growing yellow-feathered male chickens were allotted to five dietary ME levels (2805, 2897, 2997, 3095 and 3236 kcal/kg). The results revealed that the daily metabolizable energy intake increased (p < 0.01), whereas the feed intake and feed:gain ratio decreased linearly (p < 0.01) with the increment in dietary ME level. The final body weight and daily gain of the highest ME treatment tended (p > 0.05) to be greater than those obtained with the lower ME levels. The fat content in breast muscle showed a quadratic response (p < 0.05) to the increase in dietary energy level. The shear force values of breast muscle in the 2897, 3095 and 3236 kcal/kg treatments were lower (p < 0.05) than those of the 2997 kcal/kg treatment. In conclusion, among the tested ME levels, 3095 kcal/kg was adequate for feed intake, shear force, and plasma uric acid, and 3236 kcal/kg tended to increase the body weight, body gain, and feed conversion ratio of Lingnan males between 9 and 15 weeks of age; further studies are still required for testing higher levels.

Custom Repair of Mandibular Bone Defects with 3D Printed Bioceramic Scaffolds

Implanting artificial biomaterial implants into alveolar bone defects with individual shape and appropriate mechanical strength is still a challenge. In this study, bioceramic scaffolds, which can precisely match the mandibular defects in macro and micro, were manufactured by the 3-dimensional (3D) printing technique according to the computed tomography (CT) image. To evaluate the stimulatory effect of the material substrate on bone tissue regeneration in situ in a rabbit mandibular alveolar bone defect model, implants made with the newly developed, mechanically strong ~10% Mg-substituted wollastonite (Ca_90%Mg_10%SiO₃; CSi-Mg10) were fabricated, implanted into the bone defects, and compared with implants made with the typical Ca-phosphate and Ca-silicate porous bioceramics, such as β-tricalcium phosphate (TCP), wollastonite (CaSiO₃; CSi), and bredigite (Bred). The initial physicochemical tests indicated that although the CSi-Mg10 scaffolds had the largest pore dimension, they had the lowest porosity mainly due to the significant linear shrinkage of the scaffolds during sintering. Compared with the sparingly dissolvable TCP scaffolds (~2% weight loss) and superfast dissolvable (in Tris buffer within 6 wk) pure CSi and Bred scaffolds (~12% and ~14% weight loss, respectively), the CSi-Mg10 exhibited a mild in vitro biodissolution and moderate weight loss of ~7%. In addition, the CSi-Mg10 scaffolds showed a considerable initial flexural strength (31 MPa) and maintained very high flexural resistance during soaking in Tris buffer. The in vivo results revealed that the CSi-Mg10 scaffolds have markedly higher osteogenic capability than those on the TCP, CSi, and Bred scaffolds after 16 wk. These results suggest a promising potential application of customized CSi-Mg10 3D robocast scaffolds in the clinic, especially for repair of alveolar bone defects.

Using real-world data to evaluate the association of incretin-based therapies with risk of acute pancreatitis: a meta-analysis of 1,324,515 patients from observational studies

AIM

To investigate the real-world incidence of acute pancreatitis (AP) associated with incretin-based therapy (IBT).

METHODS

We carried out a systematic review and meta-analysis of observational studies using Medline, PubMed, Embase, the Cochrane Database, ClinicalTrials.gov and conference proceedings. We included: those studies in which AP was a pre-defined clinical outcome; longitudinal studies (case-control, cohort); studies that adjusted for confounders; studies that reported on a population exposed to IBT; studies in which non-IBT users or past users (who received IBTs >90 days before the index date) were used as the control group; studies that reported risk estimates [relative risks, odds ratios (ORs) or hazard ratios] with 95% confidence intervals (CIs) for AP event with IBT use, or that reported sufficient data to estimate these; and publications in the English language. Data were extracted by two independent investigators, and a consensus was reached with involvement of a third. Study-specific ORs from seven cohort studies and two case-control studies were meta-analysed using random-effects models. Associations were tested in subgroups representing different patient characteristics and study quality.

RESULTS

A total of nine studies that included 1,324,515 patients and 5195 cases of AP were included in our meta-analysis. The summary estimate of OR for an association between IBT and AP was 1.03 (95% CI 0.87-1.20).

CONCLUSIONS

The present meta-analysis of real-world data does not suggest that IBT is associated with AP. Although we should continue to remain vigilant, IBTs should be regarded as reasonable options to consider adding to the regimen of a patient with type 2 diabetes.

Dry Spinning of Polymer Fibers in Ternary Systems

In this work, predictions based on the 2D dry spinning model developed in Part I of this work [2] along with a die swell subroutine supplied by an industrial company, are used to compare with fiber concentration and elongation to break data from an industrial spinline. Die swell ratio predictions agree well with measured values and solidification along the spinline is shown to be due to homogeneous glass transition in the absence of phase separation. Concentration profiles along the spinline are well fit by the model using previously determined prefactors for the diffusion coefficients. A good correlation of elongation at break data is found to occur with a characteristic variable σGTP, the ratio of the rheological force of the viscoelastic Giesekus contribution to the total rheological force (Giesekus + viscous) at the glass transition point. Moreover, the regression obtained from this fit can be further used to make predictions for elongation at break under different operating conditions. Finally, the effects of spinning conditions and model parameters on fiber mechanical properties were investigated.

Dry Spinning of Polymer Fibers in Ternary Systems

This paper addresses the development and application of a two-dimensional, three component model for the dry spinning process of polymer fibers. The model presented is an expansion of a previously developed two-component dry spinning model [1] that incorporated both viscous and viscoelastic effects in the constitutive equation for the spin fluid, along with two-dimensional effects to account for radial variations in the fiber temperature and composition profiles along the spin line. The model presented in this paper includes the effects of water in the spin dope through incorporation of the diffusion equations for ternary mass transfer. Mass and energy balances on the gas side are also taken into account so that the effects of ambient conditions can be investigated. Calculations are based on the system: cellulose acetate-acetone-water. Results are presented for profiles of solvent concentration, temperature, and glass transition temperature profiles for typical industrial operating conditions. Force and stress distributions in the fiber at various points along the spinline, analyzed in terms of contributions from the viscoelastic and viscous terms in the constitutive equation, illustrate the role of these stresses in the freezing in of structure along the spinline. Model predictions are shown to be in good agreement with the principal characteristics of dry spinning.

Micronutrients-incorporated calcium phosphate particles with protective effect on osteoporotic bone tissue

BACKGROUND

Supplementation of individual micronutrient is inadequate for maintaining bone function because single micronutrient can not contribute significantly a positive remodeling balance.

OBJECTIVE

We developed the highly integrated, stably dietary multi-micronutrients with good bioavailability and low adverse effect on the improvement of bone consolidation in osteoporosis.

METHODS

The trace element-codoped calcium phosphate (teCaP) particles were prepared in the modified body fluid and carefully evaluated. Rats, aged 3 months, were ovariectomized and when 6 month intervened with the conditioned, low, moderate, and high teCaP diets.

RESULTS

The teCaP particles showed highly dissolvable in stomach juice-mimicing acidic solutions. Three months after intervention, the body weight increase showed remarkable differences among the low teCaP diet (~52 g), moderate teCaP diet (~34 g) and high teCaP diet (~23 g) group. In particular, the intake of moderate teCaP greatly improved the retention of trace elements in femural bone for better protection against the skeletal weakening, and resulted in a significant increase of bone mineral density (104.06%) in comparison with the conventional high calcium plus vitamin D3 diet (Control group).

CONCLUSIONS

These investigations improve our understanding of micronutrient retention on bone consolidation in osteoporotic bone tissue, and also provide new mild wet-chemical approach to prepare potent nutritionally effective edible complements to synergistically relieve bone degeneration and prevent osteoporosis.

Trace element-incorporating octacalcium phosphate porous beads via polypeptide-assisted nanocrystal self-assembly for potential applications in osteogenesis

The promising future of calcium phosphates (CaP) as a group of biomedical materials with a wide range of functions, might ultimately depend on tuning their composition and microstructure. However, the disorderly growth and aggregation of CaP nanocrystals limit their practical application. This paper reports a strategy for designing polypeptide/trace elements (TE), dual mediating the self-assembly of octacalcium phosphate (OCP) nanocrystals, with multilayered porous cross section and TE dilute doping. Intriguing advantages such as bead morphology, mesoporous structure, tunable diameter (20-1,000 μm) and TE contents, biodegradability and bioactivity are obtained. The microcomputerized-tomography reconstruction reveals an interconnective macroporous architecture and a void volume of over 49.02% for the nearly close-packed bead scaffolds. The specific surface area and average mesopore size are 89.73 m(2)g(-1) and 2.75 nm for the 180 μm diameter bead group, and those of 500 μm diameter beads are 130.17 m(2)g(-1) and 3.69 nm, respectively. It is demonstrated that the bead production mechanism is a multistep process including liquid-like precursor formation, nanocrystal nucleation and aggregation, aggregate combination and bead growth. Such a multilayer structure of TE-OCP porous beads would have adequate physical strength to maintain their shape, in contrast to the physical weakness of pure OCP hollow shell. The beads exhibit good biocompatibility and degradability and encourage bone mineralization in the early stage in vivo. This study demonstrates the feasibility of developing highly porous calcium phosphate giant beads via biomimetic self-assembly for direct application in reconstructive surgery and other widespread applications such as tissue engineering and drug delivery.

[Chemical constituents of Cynanchum chinense R. Br]

OBJECTIVE

To investigate the chemical constituents in the aerial part of Cynanchum chinense.

METHOD

The chemical constituents were extracted with solvent and separated by column chromatography. The structures were identified by spectral methods:

RESULT

The structures were identified as 7-O-alpha-L-rhamnopy-ranosyl-kaempferol-3-O-alpha-L-rhamnopyranoside, 7-O-alpha-L-rhamnopy-ranosyl-kaempferol-3-O-beta-D-glucopyranoside and 7-O-alpha-L-rhamnopyr-anosylkaempferol-3-O-beta-D-glucopyranosyl(1-->2)- beta-D-glucopyranoside.

CONCLUSION

All the three compounds were separated from C. chinense for the first time.

[The protective effect of Hippophae rhamnoides L. on hyperlipidemic serum cultured smooth muscle cells in vitro]

The effect of Hippophae rhamnoides on hyperlipidemic rabbit serum (HRS) cultured smooth muscle cells (SMC) was observed in comparison with vitamin E(VE). The results show that Hippophae rhamnoides, much like VE, is also a potent antioxidant. It strongly decreases the MDA content in HRS cultured SMC and protect the cells from the injury of lipid peroxidation, and thus keeps the SMC growing and proliferating health. The results implicate that Hippophae rhamnoides is an effective antioxidant, and one of the important mechanisms of Hippophae rhamnoides in anti-atherosclerosis reported recently may be closely related to the action of anti-lipid peroxidation.