Comprehending the impact of berberine on anaerobic digestion of waste activated sludge

Berberine is a natural isoquinoline alkaloid performing wide-spectrum antimicrobial and antiviral effects like antibiotics. Its production generates berberine containing wastewater, and berberine adsorbed on waste activated sludge (WAS) will unavoidably enter the anaerobic digestion (AD) system while its impact on the AD process is unknown. Our research found that berberine of 20 mg/L (BBR20) slightly enhanced the methane yield (4.2 ± 0.6%) under mesophilic condition (35.0 ± 1.0 °C). However, 100 and 500 mg/L (BBR100 and BBR500) depressed methane production by 17.3 ± 4.3% and 83.2 ± 0.4%; meanwhile more soluble chemical oxygen demand (SCOD) including volatile fatty acid (VFA), protein, and polysaccharide were left in the fermentation broth, which led to an increase in sludge reduction. 88.3 ± 0.09%-99.1 ± 0.04% of berberine was distributed in the sludge phase and could be efficiently removed even under a high berberine level of 500 mg/L during the AD process. Exposure to different berberine concentrations promoted sludge dissolution and triggered more sludge extracellular polymeric substances (EPS) being dissolved. Lower berberine concentration (20 mg/L) enhanced acidification and methanogenesis steps, resulting in a final methane generation increase. While hydrolysis, acidification and methanogenesis processes were all inhibited by 100 and 500 mg/L berberine. Microbial analysis revealed that the main acid-producing bacteria genera were changed as Bacteroidetes vadinHA17 dominated in control, BBR20 and BBR100 groups, was replaced by Petrimonas in BBR500. Additionally, Methanosaeta, as a strict acetoclastic methanogen, was suppressed under exposure to 100 and 500 mg/L berberine. Accordingly, the declined abundance of archaea genera consuming acetic acid caused more VFA accumulation and less methane production in BBR100 and BBR500 groups.

Protective effects of berberine against β-amyloid-induced neurotoxicity in HT22 cells via the Nrf2/HO-1 pathway

Neuronal apoptosis has been found to have a pivotal role in the course of Alzheimer's disease (AD). Berberine (BBR), a potent antioxidant, occurs in plants such as Berberis, Phellodendron chinense, and Hydrastis canadensis. In this study, a neuronal apoptotic model was established in vitro using HT22 cells induced by Aβ_25-35 to explore whether BBR contributes to protecting neurons against Aβ_25-35-induced neurotoxicity, as well as its potential mechanisms. BBR was applied to HT22 cells for 1 h prior to exposing the cells to Aβ_25-35 for 24 h. A CCK-8 assay was utilized to assess cell viability, and Annexin V - fluorescein isothiocyanate (FITC)/propidium iodide and Hoechst 33342 fluorescence staining were used to measure the rate of cell apoptosis. Existing scientific literature was also reviewed to further determine the effects of BBR on ROS production and mitochondrial function in HT22 cells. Furthermore, the expressions of proteins, including cytochrome C, cleaved caspase-3, p-p65, p65, and Nrf2/HO-1 antioxidant axis were assessed by Western blotting. The data indicated that BBR markedly improved cell viability, inhibited apoptosis and intracellular ROS levels, improved mitochondrial membrane potentials, decreased the rate of p-p65/p65, cytochrome C, and cleaved caspase-3, and intensified the activity of Nrf2/HO-1 antioxidants in HT22 cells. Overall, the findings indicated that BBR provides a certain level of neuroprotectiveness in HT22 cells exposed to Aβ_25-35 via relieving oxidative stress, as well as by restraining the mitochondrial pathway of cellular apoptosis. In addition, the restraint of NF-κB activity and sensitization of the Nrf2/HO-1 antioxidant axis, which together are intimately involved in the neuroprotection of BBR, may be possible mechanisms accounting for its effectiveness against Aβ_25-35in vitro.

Characterization of Heterogeneity and Dynamics of Lysis of Single Bacillus subtilis Cells upon Prophage Induction During Spore Germination, Outgrowth, and Vegetative Growth Using Raman Tweezers and Live-Cell Phase-Contrast Microscopy

A prophage comprises a bacteriophage genome that has integrated into a host bacterium's DNA, which generally permits the cell to grow and divide normally. However, the prophage can be induced by various stresses, or induction can occur spontaneously. After prophage induction, viral replication and production of endolysins begin until the cell lyses and phage particles are released. However, the heterogeneity of prophage induction and lysis of individual cells in a population and the dynamics of a cell undergoing lysis by prophage induction have not been fully characterized. Here, we used Raman tweezers and live-cell phase-contrast microscopy to characterize the Raman spectral and cell length changes that occur during the lysis of individual Bacillus subtilis cells from spores that carry PBSX prophage during spores' germination, outgrowth, and then vegetative growth. Major findings of this work are as follows: (i) After addition of xylose to trigger prophage induction, the intensities of Raman spectral bands associated with nucleic acids of single cells in induced cultures gradually fell to zero, in contrast to the much smaller changes in protein band intensities and no changes in nucleic acid bands in uninduced cultures; (ii) the nucleic acid band intensities from an individual induced cell exhibited a rapid decrease, following a long lag period; (iii) after the addition of nutrient-rich medium with xylose, single spores underwent a long period (228 ± 41.4 min) for germination, outgrowth, and vegetative growth, followed by a short period of cell burst in 1.5 ± 0.8 min at a cell length of 8.2 ± 5.5 μm; (iv) the latent time (T_latent) between the addition of xylose and the start of cell burst was heterogeneous in cell populations; however, the period (ΔT_burst) from the latent time to the completion of cell lysis was quite small; (v) in a poor medium with l-alanine alone, addition of xylose caused prophage induction following spore germination but with longer T_latent and ΔT_burst times and without cell elongation; (vi) spontaneous prophage induction and lysis of individual cells from spores in a minimal nutrient medium were observed without xylose addition, and cell length prior to cell lysis was ∼4.1 μm, but spontaneous prophage induction was not observed in a rich medium; (vii) in a rich medium, addition of xylose at a time well after spore germination and outgrowth significantly shortened the average T_latent time. The results of this study provide new insights into the heterogeneity and dynamics of lysis of individual B. subtilis cells derived from spores upon prophage induction.

Study on the chemodrug-induced effect in nasopharyngeal carcinoma cells using laser tweezer Raman spectroscopy

To explore the effect in nasopharyngeal carcinoma (NPC) cells after treatment with chemodrugs, Raman profiles were characterized by laser tweezer Raman spectroscopy. Two NPC cell lines (CNE2 and C666-1) were treated with gemcitabine, cisplatin, and paclitaxel, respectively. The high-quality Raman spectra of cells without or with treatments were recorded at the single-cell level with label-free laser tweezers Raman spectroscopy (LTRS) and analyzed for the differences of alterations of Raman profiles. Tentative assignments of Raman peaks indicated that the cellular specific biomolecular changes associated with drug treatment include changes in protein structure (e.g. 1655 cm^-1), changes in DNA/RNA content and structure (e.g. 830 cm^-1), destruction of DNA/RNA base pairs (e.g. 785 cm^-1), and reduction in lipids (e.g. 970 cm^-1). Besides, both principal components analysis (PCA) combined with linear discriminant analysis (LDA) and the classification and regression trees (CRT) algorithms were employed to further analyze and classify the spectral data between control group and treated group, with the best discriminant accuracy of 96.7% and 90.0% for CNE2 and C666-1 group treated with paclitaxel, respectively. This exploratory work demonstrated that LTRS technology combined with multivariate statistical analysis has promising potential to be a novel analytical strategy at the single-cell level for the evaluation of NPC-related chemotherapeutic drugs.

The effect of berberine chloride and/or its combination with vancomycin on the growth, biofilm formation, and motility of Clostridioides difficile

This study aims to investigate the antimicrobial and antibiofilm activity of berberine chloride (BBR) and vancomycin (VAN) as well as synergistic combinations of BBR with VAN against Clostridioides difficile strains. The effect of different concentrations of BBR on strain motility was also assessed. Twelve C. difficile strains (two reference C. difficile 630, ATCC 9689, and one control M120, and 9 clinical C. difficile strains belonging to the PCR-ribotype (RT027)) were collected and investigated for their susceptibility to BBR and VAN in planktonic and biofilm forms. Both the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of BBR for the C. difficile strains were found to vary over a broad range (256–1.024 mg/L and 256–16.384 mg/L, respectively). The MIC and MBC of VAN also varied greatly, ranging from 0.25 to 4.0 mg/L for MIC and 0.25 to 64.0 mg/L for MBC. The synergistic effect of the sub-MIC (1/2 MIC) BBR with VAN reduced of MICs of VAN against the planktonic forms of ten C. difficile strains. The sub-MIC of BBR enhanced the biofilm formation of one strain and was found to be statistically significant. In addition, the sub-MIC of BBR with VAN surprisingly enhanced the biofilm formation of one C. difficile strain. The effect of inhibition of motility in the presence of BBR was statistically significant for 3 clinical strains (p < 0.05). Altogether, BBR exhibited strong antimicrobial activity against C. difficile, and the analysis of the combination of BBR with VAN showed a synergistic effect.

Go with the flow or solitary confinement: a look inside the single-cell toolbox for isolation of rare and uncultured microbes

With the vast majority of the microbial world still considered unculturable or undiscovered, microbiologists not only require more fundamental insights concerning microbial growth requirements but also need to implement miniaturized, versatile and high-throughput technologies to upscale current microbial isolation strategies. In this respect, single-cell-based approaches are increasingly finding their way to the microbiology lab. A number of recent studies have demonstrated that analysis and separation of free microbial cells by flow-based sorting as well as physical stochastic confinement of individual cells in microenvironment compartments can facilitate the isolation of previously uncultured species and the discovery of novel microbial taxa. Still, while most of these methods give immediate access to downstream whole genome sequencing, upscaling to higher cell densities as required for metabolic readouts and preservation purposes can remain challenging. Provided that these and other technological challenges are addressed in future innovation rounds, integration of single-cell tools in commercially available benchtop instruments and service platforms is expected to trigger more targeted explorations in the microbial dark matter at a depth comparable to metagenomics.

A Review of Experimental and Off-Label Therapies for Clostridium difficile Infection

In spite of increased awareness and the efforts taken to optimize Clostridium difficile infection (CDI) management, with the limited number of currently available antibiotics for C. difficile the halt of this increasing epidemic remains out of reach. There are, however, close to 80 alternative treatment methods with controversial anti-clostridial efficacy or in experimental phase today. Indeed, some of these therapies are expected to become acknowledged members of the recommended anti-CDI arsenal within the next few years. None of these alternative treatment methods can respond in itself to all the major challenges of CDI management, which are primary prophylaxis in the susceptible population, clinical cure of severe cases, prevention of recurrences, and forestallment of asymptomatic C. difficile carriage and in-hospital spread. Yet, the greater the variety of treatment choices on hand, the better combination strategies can be developed to reach these goals in the future. The aim of this article is to provide a comprehensive summary of these experimental and currently off-label therapeutic options.

Stable optical trapping and sensitive characterization of nanostructures using standing-wave Raman tweezers

Optical manipulation and label-free characterization of nanoscale structures open up new possibilities for assembly and control of nanodevices and biomolecules. Optical tweezers integrated with Raman spectroscopy allows analyzing a single trapped particle, but is generally less effective for individual nanoparticles. The main challenge is the weak gradient force on nanoparticles that is insufficient to overcome the destabilizing effect of scattering force and Brownian motion. Here, we present standing-wave Raman tweezers for stable trapping and sensitive characterization of single isolated nanostructures with a low laser power by combining a standing-wave optical trap with confocal Raman spectroscopy. This scheme has stronger intensity gradients and balanced scattering forces, and thus can be used to analyze many nanoparticles that cannot be measured with single-beam Raman tweezers, including individual single-walled carbon nanotubes (SWCNT), graphene flakes, biological particles, SERS-active metal nanoparticles, and high-refractive semiconductor nanoparticles. This would enable sorting and characterization of specific SWCNTs and other nanoparticles based on their increased Raman fingerprints.