Determination of moxifloxacin in milk using a ratiometric fluorescent sensor based on Ag-MOF@curcumin.

Moxifloxacin (MFX) has attracted increasing public concern recently, and the development of a simple and effective analysis method has become a research focus. In this work, a simple, sensitive and ratiometric fluorescent sensor based on Ag-MOF@curcumin was designed and investigated. Ag-MOF@curcumin displays emission at 410 nm and 475 nm under excitation at 330 nm. When MFX is added, a new emission peak appears at 500 nm, and the F500/F410 ratio has a linear relationship with the MFX concentration in the range 0-35 µmol L-1 with a low LOD (0.179 µmol L-1). Finally, the developed sensor was used for the determination of MFX in milk. This work provides an excellent fluorescent sensor for highly selective and rapid detection of MFX residues.

Exploring possible benefits of Litsea cubeba Pers. extract on growth, meat quality, and gut flora in white-feather broilers.

White-feather broiler chickens are the dominant species in global poultry meat production. Yet there is growing concern about their health, quality, and growth efficiency. While feed additives, often antibiotics or synthetic chemicals, are used to maintain the health of the animals, drug resistance limits their use. Litsea cubeba (Lour.) Pers., a traditional Chinese herb with antibiotic-like benefits but without the risk of drug resistance, has not yet been explored as an additive to broiler diets. In the present study, broilers of the AA+ hybrid strain were randomly divided into three groups of 16: a control group (regular feed), a low-dose group (1.25 g/kg added L. cubeba extract), and a high-dose group (2.50 g/kg added L. cubeba extract). After 35 days, we found that the extract had no effect on growth. However, gut flora analysis revealed that both doses of the extract had a positive influence on amino acid content and minor unsaturated fatty acids, thus improving the flavor and nutritional value of the meat. These findings suggest that L. cubeba extract, at either dose, could serve as a sustainable alternative to antibiotics, thus reducing the risk of drug resistance while improving meat quality, nutrition, and flavor.

[Microbial Community Structure of Activated Sludge for Total Nitrogen Upgrading Project].

The activated sludge of a biochemical unit (WLK_OD) and an advanced denitrification unit (WLK_AD) were collected from a municipal wastewater treatment plant (WWTP), in which the TN concentration of effluent was less than 1.5 mg·L-1, and their microbial community structure and function profiles were analyzed using 16S rRNA gene high-throughput sequencing. The microorganisms in WLK_AD had lower evenness compared with that in WLK_OD, which was attributed to environmental selection. Furthermore, PCoA revealed that different incoming wastewaters had an impact on microbial community structure. At the phylum level, Proteobacteria (70.11%) was enriched in WLK_AD. At the genus level, Thauera, Flavobacterium, Hydrogenophaga, and Zoogloea served as distinct-dominant denitrifying bacteria in WLK_AD; however, Trichococcus (3.50%) and Terrimonas (1.10%) were enriched in WLK_OD. Through the comparison between groups (P<0.05), the biomarkers detected in each WWTP were different. Furthermore, the results of the co-occurrence network showed that the bacteria from module I had a higher proportion in WLK_AD; the bacteria from module II had a higher proportion in WLK_OD, and they were common microorganisms in WWTPs, implying that wastewater environments drpve the differences in the microbial community structure. Among the types of environmental parameters, the removal efficiency of COD and TN had the greatest impact on the microbial community by the RDA. The removal efficiency of COD was positively correlated with the dominant bacteria from WLK_OD, such as Saccharibacteria, Thermomarinilinea, Terrimonas, and Comamonas; the removal efficiency of TN was positively correlated with the denitrifying bacteria from WLK_AD, such as Dokdonella, Thauera, Flavobacterium, and Zoogloea. WLK_AD was enriched with Novosphingobium, Dokdonella, Thauera, and Sphingomonas, which synergistically removed TN, leading to the TN of the effluent being less than 1.5 mg·L-1. Moreover, based on the results of function prediction, WLK_AD had a higher proportion of genes that could code the denitrification enzymes.

Petrochemical and municipal wastewater treatment plants activated sludge each own distinct core bacteria driven by their specific incoming wastewater.

Microorganisms in activated sludge from wastewater treatment plants (WWTPs) form complex networks to convert a wide variety of pollutants, thus ensuring water purification and environmental protection. In this study, activated sludge samples were collected from three full-scale WWTPs: a petrochemical WWTP (PWWTP), a municipal WWTP treating domestic wastewater (MWWTP_D), and a municipal WWTP treating a mixture of domestic wastewater and multiple industrial effluents (MWWTP_I+D). These samples were analyzed by high-throughput sequencing of 16S rRNA gene PCoA and CPCoA indicated that the samples from three WWTPs were separated, suggesting that each WWTP had unique microbiome characters (P < 0.05). This was also evidenced by the different predominant bacteria (PDB), biomarkers, and key nodes of co-occurrence network in the three WWTPs. Microorganisms with all three above mentioned characteristics were defined the core bacteria, specifically: Georgfuchsia, Thauera and GP4 in PWWTP, Phaeodactylibacter and Hyphomicrobiuml in MWWTP_D, and Otheakwangia, Terrimonas, Phenylobacterium, etc. in MWWTP_I + D. Furthermore, in accordance with the functional profile prediction, the functional groups in PWWTP metabolized aromatic compound, sulfur compounds and heavy metal typically present in petrochemical wastewater. In contrast, the microbiome in MWWTP_D was represented by the population breaking down macromolecular biodegradable organic matter and the nitrogen nutrients that constitute the vast majority of domestic wastewater pollutants. Both functional groups coexist in MWWTP_I + D. These results revealed that the specific composition of incoming wastewaters produced distinct ecological niches and modulated the ecological structure of activated sludge microbial communities in real-world WWTPs. However, the generalization of the results of this study will require further research.

Fabrication of novel p-n heterojunction BiOI/La2Ti2O7 composite photocatalysts for enhanced photocatalytic performance under visible light irradiation.

In this paper, novel p-n type heterojunction BiOI/La2Ti2O7 nanocomposites were synthesized via a simple method for obtaining visible light activated photocatalysts. The crystal phases and crystallinity of the prepared samples were analyzed by X-ray diffraction (XRD). The morphologies of the BiOI/La2Ti2O7 composites were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The elemental composition and states were analyzed by X-ray photoelectron spectroscopy (XPS). Results showed that the obtained composites were constructed by 2D BiOI and La2Ti2O7 nanosheets. Besides, UV-vis diffuse reflectance spectrometry (DRS) indicated that BiOI/La2Ti2O7 composites possessed better visible light absorptive properties than pure La2Ti2O7. The photocatalytic activity was evaluated by the degradation of Rhodamine B (RhB), dye X-3B, methyl orange (MO) and a colorless antibiotic agent, ciprofloxacin (CIP), under visible light irradiation. Results showed that BiOI/La2Ti2O7 composites exhibited much higher activity than the corresponding single components. First of all, the enhanced activity can be ascribed to the improved visible light harvesting. Secondly, the results of photo-induced current and photoluminescence spectroscopy illustrated that the enhanced performance can also be attributed to the efficient transfer and separation of photoinduced charges, which resulted from the formed p-n heterojunctions between BiOI and La2Ti2O7. It can be expected that this novel 2D-2D p-n heterostructured photocatalyst would be a promising candidate for environmental remediation.