Insights into the reduction of antibiotic-resistant bacteria and mobile antibiotic resistance genes by black soldier fly larvae in chicken manure.

The increasing prevalence of antibiotic-resistant bacteria (ARB) from animal manure has raised concerns about the potential threats to public health. The bioconversion of animal manure with insect larvae, such as the black soldier fly larvae (BSFL, Hermetia illucens [L.]), is a promising technology for quickly attenuating ARB while also recycling waste. In this study, we investigated BSFL conversion systems for chicken manure. Using metagenomic analysis, we tracked ARB and evaluated the resistome dissemination risk by investigating the co-occurrence of antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and bacterial taxa in a genetic context. Our results indicated that BSFL treatment effectively mitigated the relative abundance of ARB, ARGs, and MGEs by 34.9%, 53.3%, and 37.9%, respectively, within 28 days. Notably, the transferable ARGs decreased by 30.9%, indicating that BSFL treatment could mitigate the likelihood of ARG horizontal transfer and thus reduce the risk of ARB occurrence. In addition, the significantly positive correlation links between antimicrobial concentration and relative abundance of ARB reduced by 44.4%. Moreover, using variance partition analysis (VPA), we identified other bacteria as the most important factor influencing ARB, explaining 20.6% of the ARB patterns. Further analysis suggested that antagonism of other bacteria on ARB increased by 1.4 times, while nutrient competition on both total nitrogen and crude fat increased by 2.8 times. Overall, these findings provide insight into the mechanistic understanding of ARB reduction during BSFL treatment of chicken manure and provide a strategy for rapidly mitigating ARB in animal manure.

Inhibition mechanism of melanin formation based on antioxidant scavenging of reactive oxygen species.

The production of reactive oxygen species (ROS) leads to the generation of oxidative stress, which will result in the excessive production and accumulation of melanin in the body and even the occurrence of some skin diseases. The intervention of antioxidants can slow down the rate of melanin formation to some extent. In order to explore the relationship between ROS, melanin and antioxidants, this work investigated the effects of antioxidants on melanin formation by the scavenging of ROS in vitro, where zebrafish were used as the model organism in in vivo experiments. The results showed that the inhibition order of natural antioxidants on melanin formation was GSH > AA > GA and PG > BHT > BHA for synthetic antioxidants. Between natural antioxidants and synthetic antioxidants, the former mainly have a strong scavenging ability on ˙OH and 1O2, while the latter have a strong scavenging ability on O2˙-. At the same time, the results in vivo showed that GSH and PG within a certain concentration not only did not affect the hatchability, survival rate and teratogenic rate of zebrafish embryos, but also can significantly inhibit melanin formation in zebrafish embryos. The results of this study have an important guiding significance for the dosage of antioxidants used in the cosmetics and food industries.

Nitrous oxide (N2O) Emissions at the Air-Water-Sediment Interfaces of Cascade Reservoirs in the Yunnan-Guizhou Plateau: Spatial Patterns and Environmental Controls.

The construction of cascade reservoirs can interfere with the natural hydrologic cycles of basins, causing negative environmental effects such as altering the emission patterns of the Nitrous oxide (N2O), a potent greenhouse gas. To elucidate the impact of cascade reservoirs construction on river N2O emissions, we utilized the thin boundary model and the incubation experiments to estimate the N2O fluxes at the air-water interface and at the water-sediment interface of cascade reservoirs on the Yunnan-Guizhou Plateau, respectively. Additionally, we explored the influence of various factors, with particular emphasis on damming, on N2O emissions and production. Moreover, we identified the main pathways of N2O production and proposed management strategies to mitigate N2O emissions from cascade reservoirs. The findings revealed that N2O fluxes at the air-water interface and the water-sediment interface were 4.73 ± 1.32 µmol · m-2 · d-1 and 15.56 ± 1.98 µmol · m-2 · d-1, respectively. Influenced by temperature, dissolved oxygen (DO), resource substances (active nitrogen substrates and dissolved organic carbon (DOC)) and reservoir properties (scale, hydraulic retention time (HRT), reservoir age, etc.), the N2O concentration and flux exhibited notable spatial heterogeneity, gradually increasing downstream. Temperature has a significant direct impact on N2O flux, as well as indirect effects through DO and resource chemicals. Furthermore, the correlation between dissolved oxygen utilization rate (AOU) and net N2O flux (△N2O) indicated that N2O emissions at the water-air interface were primarily attributable to nitrification, whereas those at the water-sediment interface were predominantly driven by denitrification. These findings not only enhance our comprehension of N2O emissions at various interfaces of cascade reservoirs but also offer theoretical backing for the formulation of management strategies aimed at efficiently mitigating N2O emissions from continuously dammed rivers.

Stimulating the biofilm formation of Bacillus populations to mitigate soil antibiotic resistome during insect fertilizer application.

Antibiotic resistance in soil introduced by organic fertilizer application pose a globally recognized threat to human health. Insect organic fertilizer may be a promising alternative due to its low antibiotic resistance. However, it is not yet clear how to regulate soil microbes to reduce antibiotic resistance in organic fertilizer agricultural application. In this study, we investigated soil microbes and antibiotic resistome under black soldier fly organic fertilizer (BOF) application in pot and field systems. Our study shows that BOF could stimulate ARB (antibiotic resistant - bacteria) - suppressive Bacillaceae in the soil microbiome and reduce antibiotic resistome. The carbohydrate transport and metabolism pathway of soil Bacillaceae was strengthened, which accelerated the synthesis and transport of polysaccharides to form biofilm to antagonistic soil ARB, and thus reduced the antibiotic resistance. We further tested the ARB - suppressive Bacillus spp. in a microcosm assay, which resulted in a significant decrease in the presence of ARGs and ARB together with higher abundance in key biofilm formation gene (epsA). This knowledge might help to the development of more efficient bio-fertilizers aimed at mitigating soil antibiotic resistance and enhancing soil health, in particular, under the requirements of global "One Health".

A label-free PEC aptasensor platform based on g-C3N4/BiVO4 heterojunction for tetracycline detection in food analysis.

A simple low-cost label-free photoelectrochemical (PEC) biosensing platform based on red blood cell shaped BiVO4 modified g-C3N4 was designed for tetracycline detection under room temperature. The prepared g-C3N4/BiVO4 heterojunction not only demonstrated a high surface area, excellent physicochemical stability and favorable PEC activity, but also can be employed as nanostructure support for aptamers to construct a visible-light-driven PEC aptasensor due to rich π-π accumulation sites. More importantly, the proposed PEC aptasensor showed a favorable linear toward tetracycline in the range from 5 × 10-9 to 2 × 10-7 M with a detection limit of 1.6 nM, which well covered the Food Standards Testing requirements. Practical food sample analysis further revealed the accuracy and feasibility of the g-C3N4/BiVO4 heterostructure based PEC platform. It is expected that such a label-free and cost-effective PEC strategy should act as a promising candidate for tetracycline determination in food quality control and supervision.

Integrated transcriptomics and lipidomics investigation of the mechanism underlying the gastrointestinal mucosa damage of Loropetalum chinense (R.Br.) and its representative component.

BACKGROUND: Loropetalum chinensis (R.Br) Oliv (Bhjm), a Chinese folk herbal medicine, was traditionally used in the treatment of wound bleeding and skin ulcers. A new drug named JIMUSAN granules used for gastrosia was developed by our group, and clinical trials have been approved. However, as the principal herb, the material basis and underlying mechanisms of Bhjm in attenuating gastrointestinal mucosa damage (GMD) remain to be systemically illuminated. PURPOSE: An integrated strategy was used to explore the therapeutic effects and mechanisms of Bhjm and ellagic acid (EA) on GMD zebrafish, using network pharmacology, transcriptomics, lipidomics, and real-time quantitative PCR (RT-qPCR) verification. METHODS: First, network pharmacological analysis was used to infer the major effective constituents and targets of Bhjm. Ultra high performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry (UHPLC-LTQ-Orbitrap HRMS) and ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) were employed to identify the chemical constituents and quantify the different types of constituents. Second, zebrafish model of GMD was established by using 2,4,6-trinitrobenzenesulfonic acid (TNBS) to evaluate the efficacy of Bhjm and EA. The potential mechanism was examined by integrated transcriptomics and lipidomics analysis. Finally, validation tests were implemented using RT-qPCR. RESULTS: In this study, targets indentified by network pharmacology were related to inflammation and mucosal damage. Ten representative components that interacted with these targets were simultaneously determined by UHPLC-MS/MS. Sixty four compounds were identified or tentatively characterized, most of which were flavonoids and polyphenols. Bhjm and EA alleviated mucosal damage and reduced inflammation in a TNBS-induced zebrafish GMD model, indicating that EA was the main active compounds. Eight common differentially expressed genes were downregulated by Bhjm and EA, as determined by transcriptomics analysis. Lipidomics analysis confirmed 12 differential lipids, including phosphatidylcholine (PC) and triglyceride (TG). Further network enrichment analysis demonstrated that differential lipid metabolism was regulated by klf4 and hist1h2ba, and were validated by RT-qPCR. CONCLUSION: In our study, the chemical profile of Bhjm was clarified. Moreover, the GMD repair effect and the mechanism of Bhjm and EA was comprehensively analyzed for the first time, involving inflammation and lipid metabolism. Collectively, these findings will be significantly helpful for deeply exploring the clinical application value of Bhjm.

Mitigation of antibiotic resistome in swine manure by black soldier fly larval conversion combined with composting.

The increasing prevalence of antibiotic resistance genes (ARGs) in animal manure has attracted considerable attention because of their potential contribution to the development of multidrug resistance worldwide. Insect technology may be a promising alternative for the rapid attenuation of ARGs in manure; however, the underlying mechanism remains unclear. This study aimed to evaluate the effects of black soldier fly (BSF, Hermetia illucens [L.]) larvae conversion combined with composting on ARGs dynamics in swine manure and to uncover the mechanisms through metagenomic analysis. Compared to natural composting (i.e. without BSF), BSFL conversion combined with composting reduced the absolute abundance of ARGs by 93.2 % within 28 days. The rapid degradation of antibiotics and nutrient reformulation during BSFL conversion combined with composting indirectly altered manure bacterial communities, resulting in a lower abundance and richness of ARGs. The number of main antibiotic-resistant bacteria (e.g., Prevotella, Ruminococcus) decreased by 74.9 %, while their potential antagonistic bacteria (e.g., Bacillus, Pseudomonas) increased by 128.7 %. The number of antibiotic-resistant pathogenic bacteria (e.g., Selenomonas, Paenalcaligenes) decreased by 88.3 %, and the average number of ARGs carried by each human pathogenic bacterial genus declined by 55.8 %. BSF larvae gut microbiota (e.g., Clostridium butyricum, C. bornimense) could help reduce the risk of multidrug-resistant pathogens. These results provide insight into a novel approach to mitigate multidrug resistance from the animal industry in the environment by using insect technology combined with composting, in particular in light of the global "One Health" requirements.

Morphometric Characteristic of Black Soldier Fly (Hermetia illucens) · Wuhan Strain and Its Egg Production Improved by Selectively Inbreeding.

The use of black soldier fly (BSF) larvae to recycle various organic materials while producing biomass for use as feed is well established. Variety selection is important from the perspective of application. In the current study, morphometric and life-history traits of a Wuhan-domesticated BSF colony (Wuhan strain) were compared to those of a 'selectively inbred' population (inbred strain, inbred for 10 generations). In terms of morphological characteristics, the results showed that both strains had dichoptic compound eyes, club-shaped antennae, blue halters, and blue-green metallic luster wings with a hexagon discal cell. In both strains, the body and wing length of female adults were slightly larger than those of male adults. The first four larval stages of the BSF occurred rapidly (1-12 days) with transitions across stages resulting in doubling of size for both populations. Selective inbreeding did not alter the life-history traits of the larval exuviate stage in terms of age, size, weight, and feed reduction rate. Overall egg production for the inbred strain was significantly higher (1.5 times greater) than the Wuhan strain. This is explained by increased adult emergence and individual oviposition performance. It was speculated that inbreeding improved the reproductive success of inbred adult female offspring and selection process steadied it. The findings indicate that selective inbreeding could enhance overall oviposition performance and provide a strategy to selectively breed BSF with high egg production for future applications.