Unmarked Gene Editing in Clavibacter michiganensis Using CRISPR/Cas9 and 5-Fluorocytosine Counterselection.

Plant-pathogenic bacteria in the genus Clavibacter are important quarantine species that cause considerable economic loss worldwide. The development of effective gene editing techniques and additional selectable markers is essential to expedite gene functional analysis in this important Gram-positive genus. The current study details a highly efficient unmarked CRISPR/Cas9-mediated gene editing system in Clavibacter michiganensis, which couples the expression of cas9 and single-guide RNA with homology-directed repair templates and the negative selectable marker codA::upp within a single plasmid. Initial experiments indicated that CRISPR/Cas9-mediated transformation could be utilized for both site-directed mutagenesis, in which an A to G point mutation was introduced at the 128th nucleotide of the C. michiganensis rpsL gene to generate a streptomycin-resistant mutant, and complete gene knockout, in which the deletion of the C. michiganensis celA or katA genes resulted in transformants that lacked cellulase and catalase activity, respectively. In subsequent experiments, the introduction of the codA::upp cassette into the transformation vector facilitated the counterselection of unmarked transformants by incubation in the absence of the selective antibiotic, followed by plating on M9 agar containing 5-fluorocytosine at 100 µg/ml, in which an unmarked katA mutant lacking the transformation vector was recovered. Compared with conventional homologous recombination, the unmarked CRISPR/Cas9-mediated system was more useful and convenient because it allowed the template plasmid to be reused repeatedly to facilitate the editing of multiple genes, which constitutes a major advancement that could revolutionize research into C. michiganensis and other Clavibacter spp.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Role of Penicillin-Binding Proteins in the Viability, Morphology, Stress Tolerance, and Pathogenicity of Clavibacter michiganensis.

Previous research has shown that penicillin-binding proteins (PBPs), enzymes involved in peptidoglycan (PG) assembly, could play an important role during the induction of the viable but nonculturable (VBNC) state, which allows non-spore-forming bacteria to survive adverse environmental conditions. The current study found that Clavibacter michiganensis has seven PBPs. Mutant analysis indicated that deletion of either of the class B PBPs was lethal and that the class A PBPs had an important role in PG synthesis, with the ΔpbpC mutant having an altered cellular morphology that resulted in longer cells that were swollen at one end and had thinner cell walls. The ΔpbpC mutant was also found to produce mucoid colonies in solid culture and a lower final cell titer in liquid medium, as well as having high sensitivity to osmotic stress and lysozyme treatment and surprisingly high pathogenicity. The double mutant, ΔdacB/ΔpbpE, also had a slightly altered phenotype, resulting in longer cells. Further analysis revealed that both mutants had high sensitivity to copper, which resulted in quicker induction into the VBNC state. However, only the ΔpbpC mutant had significantly reduced survivorship in the VBNC state. The study also confirmed that the VBNC state significantly improved the survivorship of wild-type C. michiganensis cells in response to environmental stresses and systemically demonstrated the protective role of the VBNC state in C. michiganensis, which is an important finding regarding its epidemiology and has serious implications for disease management.

Poly-γ-glutamic acid production by simultaneous saccharification and fermentation using corn straw and its fertilizer synergistic effect evaluation.

Agricultural wastes rich in lignocellulosic biomass have been used in the production of poly-γ-glutamic acid (γ-PGA) through separate hydrolysis and fermentation (SHF), but this process is complicated and generates a lot of wastes. In order to find a simpler and greener way to produce γ-PGA using agricultural wastes, this study attempted to establish simultaneous saccharification and fermentation (SSF) with citric acid-pretreated corn straw. The possibility of Bacillus amyloliquefaciens JX-6 using corn straw as substrate to synthesize γ-PGA was validated, and the results showed that increasing the proportion of glucose in the substrate could improve the γ-PGA yield. Based on these preliminary results, the corn straw was pretreated using citric acid. Then, the liquid fraction (xylan-rich) was used for cultivation of seed culture, and the solid fraction (glucan-rich) was used as the substrate for SSF. In a 10-L fermenter, the maximum cumulative γ-PGA concentration in batch and fed-batch SSF were 5.08 ± 0.78 g/L and 10.78 ± 0.32 g/L, respectively. Moreover, the product from SSF without γ-PGA extraction was used as a fertilizer synergist, increasing the yield of pepper by 13.46% (P < 0.05). Our study greatly simplified the production steps of γ-PGA, and each step achieved zero emission as far as possible. The SSF process for γ-PGA production provided a simple and green way for lignocellulose biorefinery and sustainable cultivation in agriculture.

Microbiologically induced calcite precipitation technology for mineralizing lead and cadmium in landfill leachate.

As a new bioremediation technology for toxic metals, microbiologically induced calcite precipitation (MICP) is gradually becoming a research focus. This study investigated the application of MICP to mineralize toxic metals (lead and cadmium) in landfill leachate for the first time. In the experiment of remediating synthetic landfill leachate (SLL) contaminated by Pb2+, 100% of the 20 mg/L Pb2+ was removed when the maximum urease activity was only 20.96 U/ml. Scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS) and laser particle size characterizations of the precipitates indicate the formation of agglomerated square particles, 76.9% of which had sizes that ranged from 33.93 to 57.06 µm. Fourier transform infrared spectroscopic and X-ray diffraction analyses confirmed that the precipitates consisted predominantly of calcite crystals, and the unit cell lattice constants of the precipitates (a = b = 4.984 Å, c = 17.171 Å) matched those of calcite, while lead was fixed as hydrocerussite. In addition, the Pb-MICP precipitates were stable under continuous acid degradation (pH = 5.5), and only 1.76% of the lead was released after 15 days. In the verification test of toxic metals remediation in a real landfill leachate (RLL), all of the Pb2+ and Cd2+ (initial concentrations: Pb2+ = 25 mg/L; Cd2+ = 5.6205 mg/L) was mineralized simultaneously, which further confirmed the feasibility of MICP for toxic metal remediation in landfill leachate. However, optimizing the urea dosage and combining the ammonium recovery are necessary strategies required for improving the economic and environmental benefits of the MICP process.

Variation in Streptomycin Resistance Mechanisms in Clavibacter michiganensis.

Clavibacter michiganensis is the causal agent of bacterial canker of tomato, which causes significant economic losses because of the lack of resistant tomato varieties. Chemical control with streptomycin or cupric bactericides is the last defensive line in canker disease management. Streptomycin is an aminoglycoside antibiotic that inhibits protein synthesis and targets the 30S ribosomal protein RpsL. Streptomycin has been used to control multiple plant bacterial diseases. However, identification and characterization of streptomycin resistance in C. michiganensis have remained unexplored. In this study, a naturally occurring C. michiganensis strain TX-0702 exhibiting spontaneous streptomycin resistance was identified, with a minimum inhibitory concentration of 128 µg/ml. Additionally, an induced streptomycin-resistant strain BT-0505-R was generated by experimental evolution of the sensitive C. michiganensis strain BT-0505. Genome sequencing and functional analyses were used to identify the genes conferring resistance. A point mutation at the 128th nucleotide in the rpsL gene of strain BT-0505-R is responsible for conferring streptomycin resistance. However, in TX-0702, resistance is not attributed to mutation of rpsL, streptomycin inactivation enzymes, or multidrug efflux pumps. The mechanism of resistance in TX-0702 is independent of previously reported bacterial loci. Taken together, these data highlight diverse mechanisms used by a Gram-positive plant pathogenic bacterium to confer antibiotic resistance.

Targeted protein delivery based on stimuli-triggered nanomedicine.

Protein-based drugs have shown unique advantages to treat various diseases in recent years. However, most protein therapeutics in clinical use are limited to extracellular targets with low delivery efficiency. To realize targeted protein delivery, a series of stimuli-triggered nanoparticle formulations have been developed to improve delivery efficiency and reduce off-target release. These smart nanoparticles are designed to release cargo proteins in response to either internal or external stimuli at pathological tissues. In this way, varieties of protein-based drugs including antibodies, enzymes, and pro-apoptotic proteins can be effectively delivered to desired sites for the treatment of cancer, inflammation, metabolic diseases, and so on with minimal side effects. In this review, recent advances in the design of stimuli-triggered nanomedicine for targeted protein delivery in different biomedical applications will be discussed. A deeper understanding of these emerging strategies helps develop more efficient protein delivery systems for clinical use in the future.

Analysis of latrine fecal odor release pattern and the deodorization with composited microbial agent.

As an important source of malodor, the odor gases emitted from public toilet significantly interfered the air quality of living surroundings, resulting in environmental problem which received little attention before. Thus, this paper explored the odor release pattern of latrine feces and deodorization effect with composited microbial agent in Chengdu, China. The odor release rules were investigated in sealed installations with a working volume of 9 L for 20 days. The odor units (OU), ammonia (NH3), hydrogen sulfide (H2S) and total volatile organic compounds (TVOC) were selected to assess the release of malodorous gases under different temperature and humidity, while the highest malodor release was observed under 45℃, with OU and TVOC concentration was 643.91 ± 2.49 and 7767.33 ± 33.50 mg/m3, respectively. Microbes with deodorization ability were screened and mixed into an agent, which composited of Bacillus amyloliquefaciens, Lactobacillus plantarum, Enterococcus faecalis and Pichia fermentans. The addition of microbial deodorant could significantly suppress the release of malodor gas during a 20-day trial, and the removal efficiency of NH3, H2S, TVOC and OU was 81.50 %, 38.31 %, 64.38 %, and 76.86 %, respectively. The analysis of microbial community structure showed that temperature was the main environmental factor driving the microbial variations in latrine feces, while Firmicutes, Actinobacteria, Proteobacteria and Bacteroidetes were the main bacteria phyla involved in the formation and emission of malodorous gases. However, after adding the deodorant, the abundance of Bacteroidetes, Proteobacteria and Actinobacteria were decreased, while the abundance of Firmicutes was increased. Furthermore, P. fermentans successfully colonized in fecal substrates and became the dominant fungus after deodorization. These results expanded the understanding of the odor release from latrine feces, and the composited microbial deodorant provided a valuable basis to the management of odor pollution.

Efficient strategy for employing HN-AD bacterium enhanced biofilter reactors to remove NH3 and reduce secondary pollution.

Heterotrophic nitrification-aerobic denitrification (HN-AD) strain (Paracoccus denitrificans HY-1) was employed in this study to enhance the removal efficiency of NH3 in a biological trickling filter (BTF) reactor. The results demonstrated that inoculation with HY-1 and packed with bamboo charcoal as filler significantly improved the RE of NH3 in BTF, reaching 96.52 % under 27 s of empty bed residence time (EBRT) and 812.56 ppm of inlet gas concentration. Meanwhile, the titer of NH4+-N, NO2--N, and NO3--N in the circulating fluid were merely 8.52 mg/L, 5.14 mg/L, and 18.07 mg/L, respectively. Microbial community and metabolism analyses revealed that HY-1 have successfully colonized in the BTF, and the high expression of denitrification-related genes (nar, nap, nir, nor and nos) further confirmed that the inoculation of HY-1 greatly improved both nitrification and denitrification metabolism. Furthermore, the biofilter reactor inoculated with HY-1 was applied at a large-scale piggery and exhibited remarkable odor removal effect, in which 99.61 % of NH3 and 96.63 % of H2S were completely eliminated. In general, the HN-AD bacterium could strengthen the performance of BTF reactor and reduce the secondary pollution of circulating fluid during bio-deodorization.

Integrating mTOR Inhibition and Photodynamic Therapy Based on Carrier-Free Nanodrugs for Breast Cancer Immunotherapy.

Conventional photodynamic therapy (PDT) in cancer treatment needs to utilize oxygen to produce reactive oxygen species to eliminate malignant tissues. However, oxygen consumption in tumor microenvironment exacerbates cancer cell hypoxia and may promote vasculature angiogenesis. Since the mammalian target of rapamycin (mTOR) signaling pathway plays a vital role in endothelial cell proliferation and fibrosis, mTOR inhibitor drugs hold the potential to reverse hypoxia-evoked angiogenesis for improved PDT effect. In this study, a carrier-free nanodrug formulation composed of Torin 1 as mTORC1/C2 dual inhibitor and Verteporfin as a photosensitizer and Yes-associated protein inhibitor is developed. These two drug molecules can self-assemble into stable nanoparticles through π-π stacking and hydrophobic interactions with good long-term stability. The nanodrugs can prompt synergistic apoptosis, combinational anti-angiogenesis, and strong immunogenic cell death effects upon near-infrared light irradiation in vitro. Furthermore, the nanosystem also exhibits improved antitumor effect, anti-cancer immune response, and distant tumor inhibition through tumor microenvironment remodeling in vivo. In this way, the nanodrugs can reverse PDT-elicited angiogenesis and promote cancer immunotherapy to eliminate tumor tissues and prevent metastasis. This nanosystem provides insights into integrating mTOR inhibitors and photosensitizers for safe and effective breast cancer treatment in clinical settings.

Lignocellulose degradation and temperature adaptation mechanisms during composting of mushroom residue and wood chips at low temperature with inoculation of psychrotolerant microbial agent.

Low ambient temperature become the limiting factor of composting in cold regions, thus hindering the recycle of agricultural and forestry wastes. In this study, the composting of mushroom residue and wood chips (MRWC) under low temperature was successfully implemented with inoculation of psychrotolerant cellulolytic microbial agent. Composting entered thermophilic stage on third day and the peak temperature reached to 66.25 °C. After 84 days of composting, the degradation rate of cellulose and hemicellulose was 40.85% and 100%, respectively and the compost product was completely mature and met the requirements of organic fertilizer. Metagenomic and transcriptome sequencing were applied to reveal the microbial composition and their substrates conversion functions and adaptation mechanisms through low to high temperatures. Streptomyces, Mesorhizobium, Devosia, Aspergillus and Mucor were dominant genera in the microbial community that were rich in genes of lignocellulose degradation. Various genes related to low temperature adaptation (fatty acid, trehalose, mannitol, betaine metabolism and cold shock mechanism) and high temperature tolerance (heat shock and antioxidant) were detected during MRWC composting. These results indicated that microbes during composting constituted a high-efficiency lignocellulosic ultilization system in cold conditions. Besides, the microbes of microbial agent, especially Streptomyces and Aspergillus, possessed numerous genes involving in lignocellulose degradation and temperature adaptation and quite different temperature response patterns were found to perform in bacteria and fungi. The transcription levels of most these genes in Aspergillus exhibited significant differences under different substrates and temperature conditions, suggesting that the inoculum was crucial to the composting process and beneficial to maintain the temperature of piles. This study demonstrated that the application of psychrotolerant microbes was a promising strategy to increase the efficiency of composting in cold regions and these results could also provided the guidance for optimizing microbial agent.

Microbiologically induced calcite precipitation (MICP) in situ remediated heavy metal contamination in sludge nutrient soil.

Microbiologically induced calcite precipitation (MICP), as a newly developing bioremediation technology, could redeem heavy metal contamination in diverse scenarios. In this study, MICP bacterium Sporosarcina ureilytica ML-2 was employed to suppress the pollution of Pb, Cd and Zn in municipal sludge nutrient soil. After MICP remediation, the exchangeable Cd and Zn in sludge nutrient soil were correspondingly reduced by 31.02 % and 6.09 %, while the carbonate-bound Pb, Cd and Zn as well as the residual fractions were increased by 16.12 %, 6.63 %, 13.09 % and 6.10 %, 45.70 %, 3.86 %, respectively. In addition, the extractable Pb, Cd and Zn either by diethylenetriaminepentaacetic acid (DTPA) or toxicity characteristic leaching procedure (TCLP) in sludge nutrient soil were significantly reduced. These results demonstrated that the bio-calcite generated via MICP helped to immobilize heavy metals. Furthermore, MICP treatment improved the abundance of functional microorganisms related to urea cycle, while reduced the overall abundance of metal resistance genes (MRGs) and antibiotic resistance genes (ARGs). This work confirmed the feasibility of MICP in remediation of heavy metal in sludge nutrient soil, which expanded the application field of MICP and provided a promising way for heavy metal pollution management.

Microbiologically induced calcite precipitation for in situ stabilization of heavy metals contributes to land application of sewage sludge.

Microbiologically induced calcite precipitation (MICP) has shed new light on solving the problem of in situ stabilization of heavy metals (HMs) in sewage sludge before land disposal. In this study, we examined whether MICP treatment can be integrated into a sewage sludge anaerobic digestion-land application process. Our results showed that MICP treatment not only prevented the transfer of ionic-state Cd from the sludge to the supernatant (98.46 % immobilization efficiency) but also reduced the soluble exchangeable Pb and Cd fractions by up to 100 % and 48.54 % and increased the residual fractions by 22.54 % and 81.77 %, respectively. In addition, the analysis of the stability of HMs in MICP-treated sludge revealed maximum reductions of 100 % and 89.56 % for TCLP-extractable Pb and Cd, respectively. Three-dimensional fluorescence, scanning electron microscopy-energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy analyses confirmed the excellent performance of the ureolytic bacteria Sporosarcina ureilytica ML-2 in the sludge system. High-throughput sequencing showed that the relative abundance of Sporosarcina sp. reached 53.18 % in MICP-treated sludge, and the urease metabolism functional genes unit increased by a maximum of 239.3 %. The MICP technology may be a feasible method for permanently stabilizing HMs in sewage sludge before land disposal.

Performance evaluation of H2S and NH3 removal by biological trickling filter reactors with various fillers under heterotrophic conditions.

A pilot-scale biological trickling filter (BTF) reactor (13.5 L) packed with different fillers (Pine bark, Cinder, Straw, and MBBR (mobile bed biofilm reactor) filler was employed to evaluate their removal performance of H2S and NH3 after heterotrophic bacterium addition, and some parameters, including different packing heights, empty bed residence time (EBRT), inlet titers, loading ratios, and restart trial, were investigated in this study. According to the experimental results, BTF filled with pine bark exhibited better removal efficiency than other reactors under a variety of conditions. The removal efficiency of H2S and NH3 reached to as high as 81.31 % and 91.72 %, respectively, with the loading range of 3.29-67.70 g/m3·h. Moreover, due to the addition of heterotrophic bacterium, the removal efficiency was enhanced and capable to eliminate majority of H2S and NH3 even though the packing height was reduced to 400 mm. After 15 days of idle, the BTF reactor was able to resume rapidly and execute deodorization with high efficiency. The degradation mechanism was further explored by a thorough examination of microbial species which degraded contaminants, as well as by functional prediction and correlation analyses. In a word, these results laid a foundation for the application of heterotrophic microorganisms in BTF, which could improve the removal efficiency of biological deodorization.

Tumor-associated monocytes promote mesenchymal transformation through EGFR signaling in glioma.

The role of brain immune compartments in glioma evolution remains elusive. We profile immune cells in glioma microenvironment and the matched peripheral blood from 11 patients. Glioblastoma exhibits specific infiltration of blood-originated monocytes expressing epidermal growth factor receptor (EGFR) ligands EREG and AREG, coined as tumor-associated monocytes (TAMo). TAMo infiltration is mutually exclusive with EGFR alterations (p = 0.019), while co-occurring with mesenchymal subtype (p = 4.7 × 10-7) and marking worse prognosis (p = 0.004 and 0.032 in two cohorts). Evolutionary analysis of initial-recurrent glioma pairs and single-cell study of a multi-centric glioblastoma reveal association between elevated TAMo and glioma mesenchymal transformation. Further analyses identify FOSL2 as a TAMo master regulator and demonstrates that FOSL2-EREG/AREG-EGFR signaling axis promotes glioma invasion in vitro. Collectively, we identify TAMo in tumor microenvironment and reveal its driving role in activating EGFR signaling to shape glioma evolution.

Mechanism of microbiologically induced calcite precipitation for cadmium mineralization.

Microbiologically induced calcite precipitation (MICP) technology shows potential for remediating heavy metal pollution; however, the underlying mechanism of heavy metal mineralization is not well-understood, limiting the application of this technology. In this study, we targeted Cd contamination (using 15:1, 25:1, and 50:1 Ca2+/Cd2+ molar ratios) and showed that the ureolytic bacteria Sporosarcina ureilytica ML-2 removed >99.7 % Cd2+ with a maximum fixation capacity of 75.61 mg-Cd/g-CaCO3 and maximum precipitation production capacity of 135.99 mg-CaCO3/mg-cells. Quantitative PCR analysis showed that Cd2+ inhibited the expression of urease genes (ureC, ureE, ureF, and ureG) by 70 % in the ML-2 strain. Additionally, the pseudo-first-order kinetics model (R2 = 0.9886), intraparticle diffusion model (R2 = 0.9972), and Temkin isotherm model (R2 = 0.9828) described the immobilization process of Cd2+ by bio calcite in MICP-Cd system. The three Cd2+ mineralization products generated by MICP were attributed to surface precipitation (Cd2+ → Cd(OH)2), direct binding with the CO32-/substitution calcium site of calcite (Cd2+ → CdCO3, otavite), and calcite lattice vacancy anchors (Cd2+ → (CaxCd1-x)CO3). Our findings improve the understanding of the mechanisms by which MICP can achieve in situ stabilization of heavy metals.

Study on anaerobic co-digestion of municipal sewage sludge and fruit and vegetable wastes: Methane production, microbial community and three-dimension fluorescence excitation-emission matrix analysis.

Constantly increased sewage sludge (SS) and fruit and vegetable wastes (FVW) are becoming the major organic solid wastes in human society. Thus, anaerobic digestion is employed as a low carbon energy strategy to reduce their environmental pollution risk. Anaerobic co-digestion system was developed based on the carbon to nitrogen ratio strategy. Results showed that the daily biogas production was higher in co-digester, and the volumetric biogas production rate (VBPR) significantly enhanced for 1.3 âˆ¼ 3 folds, and the highest VBPR was 2.04 L/L • day with optimal OLR of 2.083 Kg L-1 d-1. Analytic results indicated that co-digestion could improve the biodegradable of feedstocks, which transforming to more VFAs and biogas. Compared with mono SS digester, mixed substrates relieved ammonia nitrogen inhibition and enhanced the hydrolytic acidification and methanogenesis. Meanwhile, the excessive humification of organics was suppressed. This study supported the concepts of improving carbon recovery from SS and FVW.

Improvement of sewage sludge anaerobic digestion through synergistic effect combined trace elements enhancer with enzyme pretreatment and microbial community response.

In this study, a double E strategy (enzymes and enhancer) characterized by high efficiency for enhancing sewage sludge anaerobic digestion (AD) is proposed. This strategy combines addition of trace elements (TEs) enhancer and enzyme pretreatment, inducing a synergistic effect on AD, and it is more effective and economical compared with TEs addition or enzyme pretreatment in isolation. When adding 400 U/g cocktail enzymes and 1.24% trance elements enhancers, the cumulative methane production and the maximum daily methane increased yield by 45.29% and 84.7%, respectively. According to microbial community analysis, the double E strategy significantly motivate the growth of acetogens and protein fermenting bacterium. The relative abundance of Fermentimonas and Lutispora increased by 6.15% and 5.4%, respectively. Archaeal community analysis and changes in the mcrA gene abundance demonstrate enrichment of hydrogenotrophic methanogens, with the methanogens exhibiting high vitalities and stress resistance. The double E strategy could be a promising way to improve industrial sewage sludge AD efficiency.

Nitrogen removal characteristics of efficient heterotrophic nitrification-aerobic denitrification bacterium and application in biological deodorization.

A heterotrophic nitrifying aerobic denitrifying (HN-AD) strain HY-1 with excellent capacity, identified as Paracoccus denitrificans, was isolated from activated sludge. HY-1 was capable of removing NH4+, NO2-, and NO3- with the corresponding rate of 17.33 mg-N L-1 h-1, 21.83 mg-N L-1 h-1, and 32.37 mg-N L-1 h-1, as well as the mixture of multiple nitrogen sources. Meanwhile, HY-1 could execute denitrification function under anaerobic conditions with a rate of 14.56 mg-N L-1 h-1. HY-1 required less energy investment, which exhibited average denitrification rate of 5.19 mg-N L-1 h-1 at carbon-nitrogen ratio was 1. After nitrification-denitrification metabolic pathway analysis, HY-1 was applied in a biological trickling filter reactor for compost deodorization. The results showed that adding of HY-1 greatly reduced the ionic concentration of NH4+ and NO3- in the circulating liquid without impairing the deodorization effect (NH3 removal rate＞98.07%). These findings extend the field of application of HN-AD and provide new insights for biological deodorization.

Alantolactone-Loaded Pegylated Prodrug Nanocarriers for Synergistic Treatment of Cisplatin-Resistant Ovarian Cancer via Reactivating Mitochondrial Apoptotic Pathway.

Ovarian cancer (OV) seriously damages women's health because of refractory OV and the development of platinum (Pt) resistance. New treatment strategies are urgently needed to deal with the treatment of cisplatin-resistant OV. Here, a reduction-sensitive pegylated Pt(IV) prodrug was synthesized by amidation of methoxy polyethylene glycol amine (PEG750-NH2) with monocarboxylic Pt(IV) prodrug (Pt(IV)-COOH). Then alantolactone (AL) loaded PEG-Pt(IV) nanocarriers (NP(Pt)@AL) were prepared. In the cisplatin-resistant model of OV, cancer cells actively ingest NP(Pt)@AL through endocytosis, and AL and Pt(II) were disintegrated and released under high intracellular reductant condition. The activity of thioredoxin reductase 1 (TrxR1) inhibited by AL and the adducts of Pt(II) with mitochondrial DNA (mDNA) can costimulate reactive oxygen species (ROS) and reactivate the mitochondrial pathway of apoptosis. Meanwhile, Pt(II) binds with nuclear DNA (nDNA) to jointly promote cell apoptosis. Both in vitro and in vivo results demonstrated that NP(Pt)@AL could effectively reverse the drug resistance and displayed excellent synergistic therapeutic efficacy on platinum-resistant OV with high safety. Therefore, reactivation of the mitochondrial pathway of apoptosis would be a potential strategy to improve the therapeutic effect of Pt-based chemotherapy and even reverse drug resistance.

Modular configurations of living biomaterials incorporating nano-based artificial mediators and synthetic biology to improve bioelectrocatalytic performance: A review.

Currently, the industrial application of bioelectrochemical systems (BESs) that are incubated with natural electrochemically active microbes (EABs) is limited due to inefficient extracellular electron transfer (EET) by natural EABs. Notably, recent studies have identified several novel living biomaterials comprising highly efficient electron transfer systems allowing unparalleled proficiency of energy conversion. Introduction of these biomaterials into BESs could fundamentally increase their utilization for a wide range of applications. This review provides a comprehensive assessment of recent advancements in the design of living biomaterials that can be exploited to enhance bioelectrocatalytic performance. Further, modular configurations of abiotic and biotic components promise a powerful enhancement through integration of nano-based artificial mediators and synthetic biology. Herein, recent advancements in BESs are synthesized and assessed, including heterojunctions between conductive nanomaterials and EABs, in-situ hybrid self-assembly of EABs and nano-sized semiconductors, cytoprotection in biohybrids, synthetic biological modifications of EABs and electroactive biofilms. Since living biomaterials comprise a broad range of disciplines, such as molecular biology, electrochemistry and material sciences, full integration of technological advances applied in an interdisciplinary framework will greatly enhance/advance the utility and novelty of BESs. Overall, emerging fundamental knowledge concerning living biomaterials provides a powerful opportunity to markedly boost EET efficiency and facilitate the industrial application of BESs to meet global sustainability challenges/goals.