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Lanthipeptides are one of the largest groups of ribosomally synthesized and post-translationally modified peptides (RiPPs) and are characterized by the presence of lanthionine (Lan) or methyllanthionine residues (MeLan). Only very few lanthipeptides contain a C-terminal 2-aminovinyl-cysteine (AviCys) motif, but all of them show potent antibacterial activities. Recent advances of genome sequencing led to the rapid accumulation of new biosynthetic gene clusters (BGCs) for lanthipeptides. In this study, through our genome mining strategy, we found the AviCys containing lanthipeptides are widespread in the bacterial kingdom. A lanthipeptide-type biosynthetic gene cluster was identified from public bacterial genome database. Two new lanthipeptides, daspyromycins A and B (1 and 2) containing AviCys motif, along with two degraded products, daspyromycins C and D (3 and 4), were obtained after heterologous expression of the gene cluster in Streptomyces albus J1074. Daspyromycins A and B showed potent antimicrobial activity against a spectrum of Gram-positive and -negative bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE).

Investigation of the methanol extract of the leaves of Orthosiphon aristatus led to the isolation of four compounds. Their structures were elucidated on the basis of spectroscopic evidence and comparison with the literature. Among these compounds, compound 1 is a new lignan, and 2–4 were isolated from this plant for the first time.

Biofilm adhesion to the surface of a carrier plays an essential role during biofilm formation. Quorum quenching (QQ) has been shown to have great potential for delaying biofouling. However, little is known about whether QQ reduces the adhesion strength of biofilms during the formation process to inhibit biomass accumulation. In this study, we explored the effect of enzymatic QQ on the adhesion strength during biofilm development. In addition, a quantitative method was used to measure the adhesion strength of biofilms based on the shear force of water flow. Experimental results showed that QQ enzyme could reduce the adhesion strength of biofilms by at least 37% compared with the control. Furthermore, the biofilm accumulation rates were 0.05673 and 0.08762 h−1 with and without the QQ enzyme, illustrating a negative effect of QQ enzyme on biofilm accumulation. Specifically, QQ was confirmed to reduce extracellular polymeric substances, decrease the relative hydrophobicity, change the zeta potential by degrading signal molecules, and weaken the adhesion strength of biofilms. The successful reduction of the adhesion strength of the biofilm through QQ could provide a new strategy for the management and regulation of biofilm adhesion in the bioreactor.

An efficient, green and sustainable approach for the synthesis of novel polycyclic pyrrolidine-fused spirooxindole compounds was developed. The synthesis included a one-pot, three-component, domino reaction of (E)-3-(2-nitrovinyl)-indoles, isatins and chiral polycyclic α-amino acids under catalyst-free conditions at room temperature in EtOH–H2O. The salient features of this methodology are eco-friendliness, high yields and the ease of obtaining target compounds without the involvement of toxic solvents and column chromatography. These novel polycyclic pyrrolidine-fused spirooxindoles provide a collection of structurally diverse compounds that show promise for future bioassays and medical treatments.

3,3′-spirooxindoles are important synthetic target compounds and play special role in organic chemistry because of their extensive biological activities and applications of pharmaceutical lead discovery. In recent years, there has been a significant increase in design of new, atom economical and eco-friendly isatin-based one-pot multicomponent cascade reactions in aqueous medium for the green synthesis of 3,3′-spirooxindoles. In this review, the recent advances in this area were summarized and classified according to catalyst-free, organic-catalyzed, inorganic-catalyzed, nanometer-silica-catalyzed and enzyme-catalyzed reaction systems. These reviewed methods provide important inspiration for the synthesis of novel 3,3′-spirooxindoles and design of new pharmaceutical compounds.

In this study, we detail the development of a concise and efficient three-component protocol for the regioselective synthesis of highly functionalized bis-indoles through a one-pot, two-step sequential process starting from enaminones 1, indoles 2, and acenaphthylene-1,2-dione 3 that is catalyzed by piperidine and p-methyl benzenesulfonic acid. This protocol has several advantages including simplicity of experimental operation, high efficiency of bond formation, ready availability and low cost of starting materials, environmentally benign conditions, and target molecular diversity.

Among the various treatments, induction of synoviocyte apoptosis by natural products during a rheumatoid arthritis (RA) pathological condition can be considered to have vast potential. However, it is unclear that liquiritin, a kind of natural flavonoid extracted from the roots of Glycyrrhiza uralensis, induced the apoptosis of the synovial membrane and its molecular mechanism. In this study, interleukin-1β (IL-1β)-RA-FLS cells were incubated with different concentrations of liquiritin. An MTT assay, Hoechst 33342 staining, JC-1 staining, and Western blot were used to check the viability, cell apoptosis, mitochondrial membrane potential changes, and the expression of related proteins, respectively. In vivo, a TUNEL assay and HE staining of tissue were used for histopathological evaluation. Our results showed that liquiritin significantly inhibited the proliferation of IL-1β-induced-RA-FLS, promoted nuclear DNA fragmentation, and changed the mitochondrial membrane potential to accelerate cell apoptosis. Liquiritin downregulated the ratio of Bcl-2/Bax and inhibited the VEGF expression and phosphorylation of JNK and P38. Moreover, liquiritin improved the clinical score of rheumatism, inflammatory infiltration, and angiogenesis and induced apoptosis of the synovial tissue in vivo. Hence, liquiritin ameliorates RA by reducing inflammation, blocking MAPK signaling, and restraining angiogenesis.

Bioaerosols have widely been a concern due to their potential harm to human health caused by the carrying and spreading of harmful microorganisms. Biofiltration has been generally used as a green and effective technology for processing VOCs. However, bioaerosols can be emitted into the atmosphere as secondary pollutants from the biofiltration process. This review presents an overview of bioaerosol emissions from gas bioreactors. The mechanism of bioaerosols production and the effect of biofiltration on bioaerosol emissions were analyzed. The results showed that the bioaerosol emission concentrations were generally exceeded 104 CFU m−3, which would damage to human health. Biomass, inlet gas velocity, moisture content, temperature, and some other factors have significant influences on bioaerosol emissions. Moreover, as a result of the analysis done herein, different inactivation technologies and microbial immobilization of bioaerosols were proposed and evaluated as a potential solution for reducing bioaerosols emissions. The purpose of this paper is to make more people realize the importance of controlling the emissions of bioaerosols in the biofiltration process and to make the treatment of VOCs by biotechnology more environmentally friendly. Additionally, the present work intends to increase people’s awareness in regards to the control of bioaerosols, including microbial fragment present in bioaerosols., Highlights • The biofiltration generally emit more than 104 CFU m−3 bioaerosol. • The bioaerosol emitted from the biofiltration is a potential threat to human body. • Shear force and dilution affect the concentration of bioaerosol emissions. • PCD is promising to control bioaerosols because of few secondary pollutants.

Acidic substances, which produced during chlorinated volatile organic compounds, will corrode the commonly used packing materials, and then affect the removal performance of biofiltration. In this study, three biofilters with different filter bed structure were established to treat gaseous chlorobenzene. CaCO3 and 3D matrix material was added in filter bed as pH buffering material and filter bed supporting material, respectively. A comprehensive investigation of removal performance, biomass accumulation, microbial community, filter bed height, voidage, pressure drops, and specific surface area of the three biofilters was compared. The biofilter with CaCO3 and 3D matrix material addition presented stable removal performance and microbial community, and greater biomass density (209.9 kg biomass/m3 filter bed) and growth rate (0.033 d−1) were obtained by using logistic equation. After 200 days operation, the height, voidage, pressure drop, specific surface area of the filter bed consisted of perlite was 27.4 cm, 0.39, 32.8 Pa/m, 974,89 m2/m3, while those of the filter bed with CaCO3 addition was 28.2 cm, 0.43, 21.3 Pa/m, and 1021.03 m2/m3, and those of the filter bed with CaCO3 and 3D matrix material addition was 28.7 cm, 0.55, 17.4 Pa/m, and 1041.60 m2/m3. All the results verified the biofilter with CaCO3 and 3D matrix material addition is capable of sustaining the long-term performance of biofilters. CaCO3 could limit the changes of removal efficiency, microbial community and filter bed structure by buffering the pH variation. And 3D matrix material could maintain the filter bed structure by supporting the filter bed, regardless of the buffering effect.