Biological Activities of Citrus aurantium Leaf Extract by Optimized Ultrasound-Assisted Extraction.

Several studies have explored the biological activities of Citrus aurantium flowers, fruits, and seeds, but the bioactivity of C. aurantium leaves, which are treated as waste, remains unclear. Thus, this study developed a pilot-scale ultrasonic-assisted extraction process using the Box-Behnken design (BBD) for the optimized extraction of active compounds from C. aurantium leaves, and their antityrosinase, antioxidant, antiaging, and antimicrobial activities were evaluated. Under optimal conditions in a 150× scaleup configuration (a 30 L ultrasonic machine) of a pilot plant, the total phenolic content was 69.09 mg gallic acid equivalent/g dry weight, which was slightly lower (3.17%) than the theoretical value. The half maximal inhibitory concentration of C. aurantium leaf extract (CALE) for 2,2-diphenyl-1-picrylhydrazyl-scavenging, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-scavenging, antityrosinase, anticollagenase, antielastase and anti-matrix metalloprotein-1 activities were 123.5, 58.5, 181.3, 196.4, 216.3, and 326.4 mg/L, respectively. Moreover, the minimal inhibitory concentrations for bacteria and fungi were 150-350 and 500 mg/L, respectively. In total, 17 active compounds were detected in CALE-with linalool, linalyl acetate, limonene, and α-terpineol having the highest concentrations. Finally, the overall transdermal absorption and permeation efficiency of CALE was 95.9%. In conclusion, our CALE demonstrated potential whitening, antioxidant, antiaging, and antimicrobial activities; it was also nontoxic and easily absorbed into the skin as well as inexpensive to produce. Therefore, it has potential applications in various industries.

Ethanol Extract of Rosa laevigata Michx. Fruit Inhibits Inflammatory Responses through NF-κB/MAPK Signaling Pathways via AMPK Activation in RAW 264.7 Macrophages.

The fruit of Rosa laevigata Michx. (FR), a traditional Chinese herb utilized for the treatment of a variety diseases, has notably diverse pharmacological activities including hepatoprotective, anti-oxidant, and anti-inflammatory effects. Despite ongoing research on illustrating the underlying anti-inflammatory mechanism of FR, the principal mechanism remained inadequately understood. In this study, we investigated in depth the molecular mechanism of the anti-inflammatory actions of the ethanol extract of FR (EFR) and its potential targets using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages in vitro. We showed that EFR effectively ameliorated the overproduction of inflammatory mediators and cytokines, as well as the expression of related genes. It was further demonstrated that LPS-induced activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) were significantly inhibited by pretreatment with EFR, accompanied by a concomitant decrease in the nuclear translocation of the p65 subunit of NF-κB and activator protein 1 (AP-1). In addition, EFR pretreatment potently prevented LPS-induced decreased phosphorylation of adenosine monophosphate-activated protein kinase (AMPK). Our data also revealed that the activation of AMPK and subsequent inhibition of the mammalian target of the rapamycin (mTOR) signaling pathway was probably responsible for the inhibitory effect of EFR on LPS-induced inflammatory responses, evidenced by reverse changes observed under the condition of AMPK inactivation following co-treatment with the AMPK-specific inhibitor Compound C. Finally, the main components with an anti-inflammatory effect in EFR were identified as madecassic acid, ellagic acid, quinic acid, and procyanidin C1 by LC-MS and testified based on the inhibition of NO production and inflammatory mediator expression. Taken together, our results indicated that EFR was able to ameliorate inflammatory responses via the suppression of MAPKs/NF-κB signaling pathways following AMPK activation, suggesting the therapeutic potential of EFR for inflammatory diseases.

Improving the practicality of recombinant Escherichia coli biosensor in detecting trace Cr(VI) by modifying the cryogenic storage conditions of biosensors and applying simple pretreatment.

Hexavalent chromium (Cr(VI)) is a global environmental pollutant. To reduce the risk caused by Cr(VI), a simple, accurate, reproducible, and inexpensive method for quantifying Cr(VI) in water and soil should be developed. In this study, three types of recombinant Escherichia coli biosensors (namely T7-lux-E. coli, T3-lux-E. coli, and SP6-lux-E. coli biosensor) containing promoters (T7, T3, and SP6), chromate-sensing regulator chrB, and the reporter gene luxAB were constructed. This study investigated the effects of cryogenic freezing temperature and time on trace Cr(VI) measurement by using recombinant E. coli biosensors. The results indicated that the activity of thawed frozen SP6-lux-E. coli cells stored at -20 °C for 270 days did not differ from that of freshly prepared cells. Turbidity and conductivity in water samples and organic matter in soil interfered with Cr(VI) measurement using the biosensor. The SP6-lux-E. coli biosensor exhibited a wide measurement range and a low deviation of <5% for measuring Cr(VI) in various Cr(VI)-contaminated water and soil samples and required only a simple pretreatment or extraction process even after 270-day storage at -20 °C. To the best of our knowledge, this is the first study to report the use of recombinant biosensors for accurately measuring Cr(VI) in both water and soil.

Removal of toluene vapor in the absence and presence of a quorum-sensing molecule in a biotrickling filter and microbial composition shift.

Toluene is highly toxic and mutagenic, and it is generally used as an industrial solvent. Thus, toluene removal from air is necessary. To solve the problem of reducing high toluene concentrations with a short gas retention time (GRT), a quorum-sensing molecule [N-(3-oxododecanoyl)-L-homoserine lactone] (OHL) was added to a biotrickling filter (BTF). In this study, a BTF was used to treat synthetic and natural waste gases containing toluene. An extensive analysis was performed to understand the removal efficiency, removal characteristics, and bacterial community of the BTF. The addition of 20 µM OHL to the BTF significantly improved toluene removal, and more than 99.2% toluene removal was achieved at a GRT of 0.5 min when natural waste gas containing toluene (590-1020 ppm or 2.21-3.83 g m-3) was introduced. The maximum inlet load for toluene was 337.9 g m-3 h-1. Moreover, the BTF exhibited satisfactory adaptability to shock loading and shutdown operations. Pseudomonadaceae (33.0%) and Comamonadaceae (26.3%) were predominant bacteria in the system after a 98-day operation. These bacteria were responsible for toluene degradation. The optimal moisture content and low pressure drop for system operations demonstrated that the BTF was energy and cost efficient. Therefore, processing through a BTF with OHL is a favorable technique for toluene treatment.

Three-Stage Single-Chambered Microbial Fuel Cell Biosensor Inoculated with Exiguobacterium aestuarii YC211 for Continuous Chromium (VI) Measurement.

Chromium (VI) [Cr(VI)] compounds display high toxic, mutagenic, and carcinogenic potential. Biological analysis techniques (e.g., such as enzyme-based or cell-based sensors) have been developed to measure Cr(VI); however, these biological elements are sensitive to the environment, limited to measuring trace Cr(VI), and require deployment offsite. In this study, a three-stage single-chambered microbial fuel cell (SCMFC) biosensor inoculated with Exiguobacterium aestuarii YC211 was developed for in situ, real-time, and continuous Cr(VI) measurement. A negative linear relationship was observed between the Cr(VI) concentration (5⁻30 mg/L) and the voltage output using an SCMFC at 2-min liquid retention time. The theoretical Cr(VI) measurement range of the system could be extended to 5⁻90 mg/L by connecting three separate SCMFCs in series. The three-stage SCMFC biosensor could accurately measure Cr(VI) concentrations in actual tannery wastewater with low deviations (<7%). After treating the wastewater with the SCMFC, the original inoculated E. aestuarii remained dominant (>92.5%), according to the next-generation sequencing analysis. The stable bacterial community present in the SCMFC favored the reliable performance of the SCMFC biosensor. Thus, the three-stage SCMFC biosensor has potential as an early warning device with wide dynamic range for in situ, real-time, and continuous Cr(VI) measurement of tannery wastewater.

Anticandidal Potential of Stem Bark Extract from Schima superba and the Identification of Its Major Anticandidal Compound.

Plant-derived extracts are a promising source of new drugs. Schima superba is traditionally used in China for heat clearing, detoxification, and treatment of furuncles. In this study, the anticandidal properties and mechanism of action of S. superba (SSE) were explored using a stem bark extract. SSE possessed high polyphenol and saponin contents of 256.6 ± 5.1 and 357.8 ± 31.5 µg/mg, respectively. A clear inhibition zone was observed for C. albicans growth through the disc diffusion method and the 50% inhibition of C. albicans by SSE was 415.2 µg/mL. Transcriptomic analysis in C. albicans treated with different doses of SSE was conducted through RNA-seq. Average values of 6068 genes and 20,842,500 clean reads were identified from each sample. Among these samples, 1680 and 1956 genes were differentially expressed genes (DEGs) from the SSE treatments of 0.2 and 0.4 mg/mL, respectively. C. albicans growth was inhibited by the changes in gene expression associated with the cell wall and membrane composition including the regulation of chitin degradation and ergosterol biosynthesis. This result could be reflected in the irregularly wrinkled morphology of the ruptured cell as revealed through SEM analysis. ESI-MS and NMR analyses revealed that the major compound purified from SSE was sasanquasaponin III and the 50% inhibition of C. albicans was 93.1 µg/mL. In summary, the traditional Chinese medicine S. superba can be applied as an anticandidal agent in complementary and alternative medicine.

Antioxidant and anti-inflammatory capacities of collagen peptides from milkfish (Chanos chanos) scales.

Milkfish (Chanos chanos), which is resistant to water quality changes is the fourth largest aquaculture commodity. Abandoned wastes of fish scale and bones aggravate environmental pollution. In this study, the effect of collagen peptides isolated from milkfish scales (MSCP) by pepsin-soluble collagen method on cell viability was investigated. The antioxidant, anti-inflammatory, and DNA-protective activities of MSCP were also evaluated. Results revealed that more than 95% of viable cells were retained in human keratinocytes after addition of 100 mg/mL MSCP. Measurement of DPPH· and ABTS· + radical scavenging activities and cellular reactive oxygen species revealed the high antioxidant activities of MSCP. MSCP demonstrated anti-inflammatory activities by reducing lipoxygenase activity and nitric oxide (NO·) radicals. Moreover, DNA electrophoresis assay indicated that MSCP treatment can directly protect against cyclobutane di-pyrimidine production and DNA single-strand breaks, which are harmful effects of UV radiation and H2O2. Given its antioxidant, anti-inflammatory, and DNA-protective activities, MSCP has potential applications in cosmeceuticals and supplementary health food.

Continuous bioelectricity generation through treatment of Victoria blue R: A novel microbial fuel cell operation.

A novel two-chamber microbial fuel cell (MFC) operation with a continuous anaerobic-aerobic decolorization system was developed to improve the degradation of the triphenylmethane dye, Victoria blue R (VBR). In addition, bioelectricity was generated during the VBR degradation process, and the operation parameters were optimized. The results indicated that the VBR removal efficiency and electricity generation were affected by the VBR concentration, liquid retention time (LRT), external resistance, gas retention time (GRT), and shock loading. The optimal operation parameters were as follows: VBR concentration, 600 mg L-1; LRT, 24 h; external resistance, 3300 Ω; and GRT, 60 s. Under these operating conditions, the VBR removal efficiency, COD removal efficiency, and power density were 98.2% ± 0.3%, 97.6% ± 0.5%, and 30.6 ± 0.4 mW m-2, respectively. According to our review of the relevant literature, this is the first paper to analyze the electrical characteristics of a continuous two-chamber MFC operation and demonstrate the feasibility of the simultaneous electricity generation and decolorization of VBR.

Utility of Ochrobactrum anthropi YC152 in a Microbial Fuel Cell as an Early Warning Device for Hexavalent Chromium Determination.

Fast hexavalent chromium (Cr(VI)) determination is important for environmental risk and health-related considerations. We used a microbial fuel cell-based biosensor inoculated with a facultatively anaerobic, Cr(VI)-reducing, and exoelectrogenic Ochrobactrum anthropi YC152 to determine the Cr(VI) concentration in water. The results indicated that O. anthropi YC152 exhibited high adaptability to pH, temperature, salinity, and water quality under anaerobic conditions. The stable performance of the microbial fuel cell (MFC)-based biosensor indicated its potential as a reliable biosensor system. The MFC voltage decreased as the Cr(VI) concentration in the MFC increased. Two satisfactory linear relationships were observed between the Cr(VI) concentration and voltage output for various Cr(VI) concentration ranges (0.0125-0.3 mg/L and 0.3-5 mg/L). The MFC biosensor is a simple device that can accurately measure Cr(VI) concentrations in drinking water, groundwater, and electroplating wastewater in 45 min with low deviations (<10%). The use of the biosensor can help in preventing the violation of effluent regulations and the maximum allowable concentration of Cr(VI) in water. Thus, the developed MFC biosensor has potential as an early warning detection device for Cr(VI) determination even if O. anthropi YC152 is a possible opportunistic pathogen.

5-epi-Sinuleptolide induces cell cycle arrest and apoptosis through tumor necrosis factor/mitochondria-mediated caspase signaling pathway in human skin cancer cells.

BACKGROUND: Skin cancers are reportedly increasing worldwide. Developing novel anti-skin cancer drugs with minimal side effects is necessary to address this public health issue. Sinuleptolide has been demonstrated to possess anti-cancer cell activities; however, the mechanisms underlying the anti-skin cancer effects of 5-epi-sinuleptolide and sinuleptolide remain poorly understood. METHODS: Apoptosis cell, cell-cycle-related regulatory factors, and mitochondria- and death receptor-dependent caspase pathway in 5-epi-sinuleptolide-induced cell apoptosis were examined using SCC25 cells. RESULTS: 5-epi-Sinuleptolide inhibited human skin cancer cell growth more than did sinuleptolide. Treatment of SCC25 cells with 5-epi-sinuleptolide increased apoptotic body formation, and induced cell-cycle arrest during the G2/M phase. Notably, 5-epi-sinuleptolide up-regulated p53 and p21 expression and inhibited G2/M phase regulators of cyclin B1 and cyclin-dependent kinease 1 (CDK1) in SCC25 cells. Additionally, 5-epi-sinuleptolide induced apoptosis by mitochondria-mediated cytochrome c and Bax up-expression, down-regulated Bcl-2, and activated caspase-9 and -3. 5-epi-Sinuleptolide also up-regulated tBid, which is associated with up-regulation of tumor necrosis factor-α (TNF-α) and Fas ligand (FasL) and their cognate receptors (i.e., TNF-RI, TNF-R2 and Fas), downstream adaptor TNF-R1-associated death domain (TRADD) and Fas-associated death domain (FADD), and activated caspase-8 in SCC25 cells. CONCLUSIONS: The analytical results indicate that the death receptor- and mitochondria-mediated caspase pathway is critical in 5-epi-sinuleptolide-induced apoptosis of skin cancer cells. GENERAL SIGNIFICANCE: This is the first report suggesting that the apoptosis mediates the anti-tumor effect of 5-epi-sinuleptolide. The results of this study might provide useful suggestions for designing of anti-tumor drugs for skin cancer patients.

Broad-spectrum antiviral activity of chebulagic acid and punicalagin against viruses that use glycosaminoglycans for entry.

BACKGROUND: We previously identified two hydrolyzable tannins, chebulagic acid (CHLA) and punicalagin (PUG) that blocked herpes simplex virus type 1 (HSV-1) entry and spread. These compounds inhibited viral glycoprotein interactions with cell surface glycosaminoglycans (GAGs). Based on this property, we evaluated their antiviral efficacy against several different viruses known to employ GAGs for host cell entry. RESULTS: Extensive analysis of the tannins' mechanism of action was performed on a panel of viruses during the attachment and entry steps of infection. Virus-specific binding assays and the analysis of viral spread during treatment with these compounds were also conducted. CHLA and PUG were effective in abrogating infection by human cytomegalovirus (HCMV), hepatitis C virus (HCV), dengue virus (DENV), measles virus (MV), and respiratory syncytial virus (RSV), at µM concentrations and in dose-dependent manners without significant cytotoxicity. Moreover, the natural compounds inhibited viral attachment, penetration, and spread, to different degrees for each virus. Specifically, the tannins blocked all these steps of infection for HCMV, HCV, and MV, but had little effect on the post-fusion spread of DENV and RSV, which could suggest intriguing differences in the roles of GAG-interactions for these viruses. CONCLUSIONS: CHLA and PUG may be of value as broad-spectrum antivirals for limiting emerging/recurring viruses known to engage host cell GAGs for entry. Further studies testing the efficacy of these tannins in vivo against certain viruses are justified.

Antioxidant, anti-adipocyte differentiation, antitumor activity and anthelmintic activities against Anisakis simplex and Hymenolepis nana of yakuchinone A from Alpinia oxyphylla.

BACKGROUND: Alpinia oxyphylla is a common remedy in traditional Chinese medicine. Yakuchinone A is a major constituent of A. oxyphylla and exhibits anti-inflammatory, antitumor, antibacterial, and gastric protective activities. METHODS: Antioxidant and antitumor characteristics of yakuchinone A in skin cancer cells as well as novel mechanisms for the inhibition of adipocyte differentiation, cestocidal activities against Hymenolepis nana adults, and nematocidal activities against Anisakis simplex larvae are investigated. RESULTS: Yakuchinone A presents the ability of the removal of DPPH·and ABTS+ free radicals and inhibition of lipid peroxidation. Yakuchinone A suppresses intracellular lipid accumulation during adipocyte differentiation in 3 T3-L1 cells and the expressions of leptin and peroxisome proliferator-activated receptor γ (PPARγ). Yakuchinone A induces apoptosis and inhibits cell proliferation in skin cancer cells. The inhibition of cell growth by yakuchinone A is more significant for non-melanoma skin cancer (NMSC) cells than for melanoma (A375 and B16) and noncancerous (HaCaT and BNLCL2) cells. Treatment BCC cells with yakuchinone A shows down-regulation of Bcl-2, up-regulation of Bax, and an increase in cleavage poly (ADP-ribose) polymerase (PARP). This suggests that yakuchinone A induces BCC cells apoptosis through the Bcl-2-mediated signaling pathway. The anthelmintic activities of yakuchinone A for A. simplex are better than for H. nana. CONCLUSIONS: In this work, yakuchinone A exhibits antioxidative properties, anti-adipocyte differentiation, antitumor activity, and anthelmintic activities against A. simplex and H. nana.

Hydrolyzable tannins (chebulagic acid and punicalagin) target viral glycoprotein-glycosaminoglycan interactions to inhibit herpes simplex virus 1 entry and cell-to-cell spread.

Herpes simplex virus 1 (HSV-1) is a common human pathogen that causes lifelong latent infection of sensory neurons. Non-nucleoside inhibitors that can limit HSV-1 recurrence are particularly useful in treating immunocompromised individuals or cases of emerging acyclovir-resistant strains of herpesvirus. We report that chebulagic acid (CHLA) and punicalagin (PUG), two hydrolyzable tannins isolated from the dried fruits of Terminalia chebula Retz. (Combretaceae), inhibit HSV-1 entry at noncytotoxic doses in A549 human lung cells. Experiments revealed that both tannins targeted and inactivated HSV-1 viral particles and could prevent binding, penetration, and cell-to-cell spread, as well as secondary infection. The antiviral effect from either of the tannins was not associated with induction of type I interferon-mediated responses, nor was pretreatment of the host cell protective against HSV-1. Their inhibitory activities targeted HSV-1 glycoproteins since both natural compounds were able to block polykaryocyte formation mediated by expression of recombinant viral glycoproteins involved in attachment and membrane fusion. Our results indicated that CHLA and PUG blocked interactions between cell surface glycosaminoglycans and HSV-1 glycoproteins. Furthermore, the antiviral activities from the two tannins were significantly diminished in mutant cell lines unable to produce heparan sulfate and chondroitin sulfate and could be rescued upon reconstitution of heparan sulfate biosynthesis. We suggest that the hydrolyzable tannins CHLA and PUG may be useful as competitors for glycosaminoglycans in the management of HSV-1 infections and that they may help reduce the risk for development of viral drug resistance during therapy with nucleoside analogues.

Characterization of Tibetan kefir grain-fermented milk whey and its suppression of melanin synthesis.

Tibetan kefir grain as the starter of milk fermentation has been applied as functional food with many bioactive characteristics. In this study, the milk whey product (TKG-MW) was obtained through the milk fermentation of Tibetan kefir grain containing the dominant Lactobacillus, Acetobacter, and Bacillus after 3 and 6 days of cultivation. Antioxidant, anti-inflammatory, and melanogenesis inhibition capacities under TKG-MW treatment were analyzed. Results revealed that the antioxidation of TKG-MW at 6 days of fermentation was higher than that at 3 days of fermentation according to the DPPH and ABTS+ radical scavenging analysis. However, the anti-inflammation of TKG-MW was only observed at 6 days of fermentation by using lipopolysaccharide-stimulated RAW 264.7 macrophages. The inhibition of mushroom tyrosinase activity by TKG-MW was demonstrated. The decrease of melanin content was verified using α-melanocyte-stimulating hormone-stimulated B16-F10 cell. The real-time quantitative reverse transcription polymerase chain reaction result indicated that the mRNA levels of Tyr, Trp-1, and Trp-2 of the B16 cell involved in melanin synthesis were down-regulated over a two-fold change by the TKG-MW treatment. Additionally, the protein expressions of Tyr, Trp-1, Trp-2, and Mitf of the B16 cell were reduced with the TKG-MW treatment. Organic acids, such as lactic acid, succinic acid, 3-phenyllactic acid, l-pyroglutamic acid, and malic acid, were identified by liquid chromatography-mass spectrometry in TKG-MW and were found to significantly inhibit tyrosinase activity. To the best of our knowledge, this work is the first to report melanogenesis suppression by TKG-MW. Results suggested that the fermentation product of TKG could be applied as a depigmenting agent in food and cosmetics.

Crassocolides N-P, three cembranoids from the Formosan soft coral Sarcophyton crassocaule.

Three new cembranoids crassocolides N-P (1-3), was isolated from the organic extract of a Formosan soft coral Sarcophyton crassocaule. These structures were elucidated on the basis of spectroscopic analyses and by comparison with those previously reported in literature. The cytotoxicity of these compounds toward various cancer cell lines has also been determined.

Paraminabeolides A-F, cytotoxic and anti-inflammatory marine withanolides from the soft coral Paraminabea acronocephala.

Six new withanolides, paraminabeolides A-F (1-6), along with five known compounds, minabeolides-1, -2, -4, -5, and -8 (7-11), were isolated from a Formosan soft coral, Paraminabea acronocephala. The structures of these compounds were elucidated by extensive spectroscopic analysis and chemical transformation. The absolute configuration of 4 was determined by the application of Mosher's method. Compounds 1 and 7 were cytotoxic toward Hep G2 cancer cells. Compounds 1-4 and 7-10 were found to significantly inhibit the accumulation of the pro-inflammatory iNOS protein. Compounds 7-10 also could effectively reduce the expression of COX-2 protein.

Antioxidant and antimelanogenic behaviors of Paeonia suffruticosa.

Antioxidant properties of eight Paeonia suffruticosa (Ps) extracts (Ps-1 to Ps-8) were evaluated. The respective half maximally effective concentration (EC(50)) values of Ps-1 ~ 8 were 10.0, 9.8, 63.6, >100, 3.8, 85.1, 6.9, and 0.7 µg/ml for 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) radical scavenging efficiency and 22.9, 11.4, 53.1, >100, 7.5, 97.6, 43.7, 4.2 µg/ml for 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS·(+)) radical scavenging capacity. The Ps-8 exhibited high free radical scavenging capacity, ion-chelating ability, reducing power, and inhibition of lipid peroxidation, which may have been attributable to its abundant phenolic and flavonoid content. In Hs68 and B16 cells treated with 100 µg/ml Ps-1, Ps-3, Ps-4 and Ps-6, expressions of toxic activities were lower than those in cells treated with arbutin and ascorbic acid. The antimelanogenesis properties were also tested in B16 cells. Extract Ps-1, and particularly extract Ps-6, considerably inhibited cellular tyrosinase and 3,4-dihydroxyphenylalanine (DOPA) oxidase activity and also reduced melanin content in B16 cells by down-expression of melanocortin-1 receptor (MC1R), microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related proteins-1 (TRP-1). The results suggest that P. suffruticosa extracts have antioxidant and antimelanogenesis activities with potential applications in cosmetic materials or food additives.

Highly Sensitive Luminescent Bioassay Using Recombinant Escherichia coli Biosensor for Rapid Detection of Low Cr(VI) Concentration in Environmental Water.

In this study, we constructed a recombinant Escherichia coli strain with different promoters inserted between the chromate-sensing regulator chrB and the reporter gene luxAB to sense low hexavalent chromium (Cr(VI)) concentrations (<0.05 mg/L); subsequently, its biosensor characteristics (sensitivity, selectivity, and specificity) for measuring Cr(VI) in various water bodies were evaluated. The luminescence intensity of each biosensor depended on pH, temperature, detection time, coexisting carbon source, coexisting ion, Cr(VI) oxyanion form, Cr(VI) concentration, cell type, and type of medium. Recombinant lux-expressing E. coli with the T7 promoter (T7-lux-E. coli, limit of detection (LOD) = 0.0005 mg/L) had the highest luminescence intensity or was the most sensitive for Cr(VI) detection, followed by E. coli with the T3 promoter (T3-lux-E. coli, LOD = 0.001 mg/L) and that with the SP6 promoter (SP6-lux-E. coli, LOD = 0.005 mg/L). All biosensors could be used to determine whether the Cr(VI) standard was met in terms of water quality, even when using thawing frozen cells as biosensors after 90-day cryogenic storage. The SP6-lux-E. coli biosensor had the shortest detection time (0.5 h) and the highest adaptability to environmental interference. The T7-lux-E. coli biosensor-with the optimal LOD, a wide measurement range (0.0005-0.5 mg/L), and low deviation (-5.0-7.9%) in detecting Cr(VI) from industrial effluents, domestic effluents, and surface water-is an efficient Cr(VI) biosensor. This unprecedented study is to evaluate recombinant lux E. coli with dissimilar promoters for their possible practice in Cr(VI) measurement in water bodies, and the biosensor performance is clearly superior to that of past systems in terms of detection time, LOD, and detection deviation for real water samples.

METTL3/YTHDF2 m6A axis accelerates colorectal carcinogenesis through epigenetically suppressing YPEL5.

N6-methyladenosine (m6A) has emerged as the most prevalent post-transcriptional modification on mRNA that contributes prominently to tumorigenesis. However, the specific function of m6A methyltransferase methyltransferase-like 3 (METTL3) in colorectal cancer (CRC) remains elusive. Herein, we explored the biological function of METTL3 in CRC progression. Clinically, METTL3 was frequently upregulated in CRC tissues, cell lines, and plasma samples and its high expression predicted poor prognosis of CRC patients. Functionally, knockdown of METTL3 significantly repressed CRC cell proliferation and migration in vitro, while its overexpression accelerated CRC tumor formation and metastasis both in vitro and in vivo. Mechanistically, METTL3 epigenetically repressed YPEL5 in an m6A-YTHDF2-dependent manner by targeting the m6A site in the coding sequence region of the YPEL5 transcript. Moreover, overexpression of YPEL5 significantly reduced CCNB1 and PCNA expression. Collectively, we identified the pivotal role of METTL3-catalyzed m6A modification in CRC tumorigenesis, wherein it facilitates CRC tumor growth and metastasis through suppressing YPEL5 expression in an m6A-YTHDF2-dependent manner, suggesting a promising strategy for the diagnosis and therapy of CRC.

Analysis of bioavailable toluene by using recombinant luminescent bacterial biosensors with different promoters.

In this study, we constructed recombinant luminescent Escherichia coli with T7, T3, and SP6 promoters inserted between tol and lux genes as toluene biosensors and evaluated their sensitivity, selectivity, and specificity for measuring bioavailable toluene in groundwater and river water. The luminescence intensity of each biosensor depended on temperature, incubation time, ionic strength, and concentrations of toluene and coexisting organic compounds. Toluene induced the highest luminescence intensity in recombinant lux-expressing E. coli with the T7 promoter [T7-lux-E. coli, limit of detection (LOD) = 0.05 µM], followed by that in E. coli with the T3 promoter (T3-lux-E. coli, LOD = 0.2 µM) and SP6 promoter (SP6-lux-E. coli, LOD = 0.5 µM). Luminescence may have been synergistically or antagonistically affected by coexisting organic compounds other than toluene; nevertheless, low concentrations of benzoate and toluene analogs had no such effect. In reproducibility experiments, the biosensors had low relative standard deviation (4.3-5.8%). SP6-lux-E. coli demonstrated high adaptability to environmental interference. T7-lux-E. coli biosensor-with low LOD, wide measurement range (0.05-500 µM), and acceptable deviation (- 14.3 to 9.1%)-is an efficient toluene biosensor. This is the first study evaluating recombinant lux E. coli with different promoters for their potential application in toluene measurement in actual water bodies.