Developmental toxicity and mechanism of polychlorinated biphenyls 126 and nano-polystyrene combined exposure to zebrafish larvae.

3,3',4,4',5-Pentachlorobiphenyl (PCB126) is the most toxic congener of dioxin-like polychlorinated biphenyls (DL PCBs), while nanoplastics (NPs) have recently emerged as significant marine pollutants, both posing threats to aquatic organisms and human health. They coexist in the environment, but their comprehensive toxicological effects remain unclear. In this study, zebrafish embryos were simultaneously exposed to PCB126 and 80-nanometer nanoplastyrene (NPS). Researchers utilized fluorescence microscopy, qPCR, histopathological examination, and transcriptomic sequencing to investigate the developmental toxicity of different concentrations of PCB126 and NPS individually or in combination on zebrafish embryos and larvae. Results indicate that the chorion significantly impedes the accumulation of NPS (p < 0.05). It is noteworthy that this barrier effect diminishes upon simultaneous exposure to PCB126. In this experiment, the semi-lethal concentration of PCB126 for larvae was determined to be 6.33 µg/L. Exposure to PCB126 induces various deformities, primarily mediated through the aryl hydrocarbon receptor (AHR). Similarly, exposure to NPS also activates AHR, leading to developmental impairments. Furthermore, transcriptomic sequencing revealed similar effects of PCB126 and NPS on the gene expression trends in zebrafish larvae, but combined exposure to both exacerbates the risk of cancer and induces more severe cardiac toxicity. At this level, co-exposure to PCB126 and NPS adversely affects the development of zebrafish larvae. This study contributes to a deeper understanding of the in vivo accumulation of DL polychlorinated biphenyls and microplastics in actual aquatic environments and their impact on fish development.

Anti-Alzheimers molecular mechanism of icariin: insights from gut microbiota, metabolomics, and network pharmacology.

BACKGROUND: Icariin (ICA), an active ingredient extracted from Epimedium species, has shown promising results in the treatment of Alzheimer's disease (AD), although its potential therapeutic mechanism remains largely unknown. This study aimed to investigate the therapeutic effects and the underlying mechanisms of ICA on AD by an integrated analysis of gut microbiota, metabolomics, and network pharmacology (NP). METHODS: The cognitive impairment of mice was measured using the Morris Water Maze test and the pathological changes were assessed using hematoxylin and eosin staining. 16S rRNA sequencing and multi-metabolomics were performed to analyze the alterations in the gut microbiota and fecal/serum metabolism. Meanwhile, NP was used to determine the putative molecular regulation mechanism of ICA in AD treatment. RESULTS: Our results revealed that ICA intervention significantly improved cognitive dysfunction in APP/PS1 mice and typical AD pathologies in the hippocampus of the APP/PS1 mice. Moreover, the gut microbiota analysis showed that ICA administration reversed AD-induced gut microbiota dysbiosis in APP/PS1 mice by elevating the abundance of Akkermansia and reducing the abundance of Alistipe. Furthermore, the metabolomic analysis revealed that ICA reversed the AD-induced metabolic disorder via regulating the glycerophospholipid and sphingolipid metabolism, and correlation analysis revealed that glycerophospholipid and sphingolipid were closely related to Alistipe and Akkermansia. Moreover, NP indicated that ICA might regulate the sphingolipid signaling pathway via the PRKCA/TNF/TP53/AKT1/RELA/NFKB1 axis for the treatment of AD. CONCLUSION: These findings indicated that ICA may serve as a promising therapeutic approach for AD and that the ICA-mediated protective effects were associated with the amelioration of microbiota disturbance and metabolic disorder.

Effects of Environmental and Spatial Variables on Bacteria in Zhanjiang Mangrove Sediments.

The bottom mud of mangroves contains numerous microbial groups that play an important role in the main ecological functions of the mangrove ecosystem. The diversity and functional and environmental factors related to microbial communities, in terms of the assembly process and in environmental adaptation of the abundance and rare bacterial communities in the mangrove ecosystem, have not been fully explored. We used 16S high-throughput sequencing and operational taxonomic unit analysis to compare the diversity and composition of bacterial communities in different tidal zones in the sediments of the Zhanjiang Gaoqiao Mangrove Nature Reserve, compare the ecological adaptation thresholds and phylogenetic signals of bacterial communities under different environmental gradients, and examine the factors affecting the composition of the bacterial community. The diversity of microbial species and structure and function of the mangrove sediments were affected by the environment, showing the trend: mid tide zone > climax zone > low tide zone. Organic matter content, oxygen content, pH, and total phosphorus were identified as important environmental factors determining the functional diversity of bacterial communities and survival, while pH influences species evolution. The abundant taxa showed a wider response threshold and stronger phylogenetic signals of ecological preference across environmental gradients compared to rare taxa. The abundant bacterial groups have broader environmental adaptability than rare bacterial groups, and different environmental factors affect different communities and functions in the mangrove ecological environment. These results elucidate the mechanism underlying the generation and maintenance of bacterial diversity in response to global environmental changes.

The Status of Polychlorinated Biphenyls (PCBs) Extract from Zhanjiang Mangrove Sediments and the Effects on Tissue Structure and Inflammatory Cytokines in Zebrafish Liver.

Polychlorinated biphenyls (PCBs) are released into the environment from a wide range of sources. The aim of the present study was to investigate the effect of the PCBs extracted from the Zhanjiang mangrove sediments on the immune function of zebrafish. The sediments were collected from 3 mangrove forest points in Zhanjiang (Guangdong Province, China), and the results showed that PCB153 was detected in the sediments of the Guangdong Zhanjiang Mangrove National Nature Reserve (MNNR) and Gaoqiao Mangrove Reserve (GMR), while PCB101, PCB112, PCB155, and PCB198 were detected in the sediments of the Leizhou Peninsula (LP). The zebrafish were exposed to different concentrations of PCBs, i.e., control group, positive control group (Aroclor1254; 10 µg/L), low dose group (LD; 0.6 µg/L), medium-dose group (MD; 3.0 µg/L) and high dose group (HD; 15 µg/L) for 14 days. As compared to the control group, the liver index increased significantly in all PCB treated groups. The liver tissue structure was destroyed in all PCB-treated groups as compared to the control group. In addition, the relative mRNA expression of the target genes (IL-1ß, IL-8, and TNF-α) was significantly expressed in each concentration group. Therefore, these findings suggest that exposure of zebrafish to PCBs can destroy the liver histology and increase the liver index and mRNA expression of inflammatory cytokines in a dose and time-dependent manner.

Effects of Microplastics on Microbial Community in Zhanjiang Mangrove Sediments.

Microplastics are easily consumed by marine animals, thereby entering the food chain and endangering animal health. However, there are few studies focusing on the effects of microplastics in mangrove sediments on microbial communities. In order to study the influence of microplastics on microorganisms, microplastics and microorganisms were extracted from Zhanjiang (Guangdong Province, China) mangrove sediments and analyzed. The results showed that there were differences in Shannon and Simpson indices of the microbial community in microplastics (p < 0.05), and there were also differences between JG30_KF_CM45 and Natranaerovirga at the genus level, indicating that microplastics may affect the diversity and composition of microorganisms in sediments. In addition, FAPROTAX function prediction analysis showed that microplastics may affect the nitrification of microbial communities. The results from this study indicate that microplastics affected the diversity and richness of microorganisms in mangrove sediments, which provides an experimental basis for the relationship between microplastics and microorganisms.

Immunotoxicological effects of dioxin-like polychlorinated biphenyls extracted from Zhanjiang Bay sediments in zebrafish.

Dioxin-like polychlorinated biphenyls (DLPCBs) are ubiquitous environmental contaminants spread all over the world. They can cause disorders in the reproductive, nervous, gut, and immune systems. We investigated the effects of DL-PCB extracted from Zhanjiang (Guangdong Province, China) offshore area on the immune functions of adult zebrafish. Zebrafish were exposed to different levels of DL-PCBs, i.e., control, positive control (PCB77 at 16.0 µg/L), low (LD; PCB81 + PCB118 at 0.32 µg/L), and high-dose (HD; PCB81 + PCB118 at 16.0 µg/L) groups for 28 days. Compared with the control group, positive control and HD group showed a significant decrease (P < 0.05) in the number of red blood cells (RBC) on day 7 and the same decrease was observed in the LD group (P < 0.05) on day 21. The results of white blood cell (WBC) profiles were opposite to that of RBCs. Moreover, the serum lysozyme activity was significantly lower in positive control and HD group (P < 0.05) on day 21 but no significant effect was observed in the LD group. The mucus lysozyme activity and immunoglobulin concentration in positive control and HD group decreased significantly (P < 0.05) from day 14. A similar effect was observed in the LD group but was significant (P < 0.05) only on day 28. Additionally, histopathological examination showed accumulation of hemosiderin in the spleen of experimental animals, which was significant in positive control and HD group. Further, renal tubular epithelial cells of head kidney were swollen in the positive control and HD group while the expansion of lumen and renal interstitial edema was observed in the LD group on day 21 and with significant presence on 28 days. Therefore, these findings suggest that the exposure of zebrafish to DL-PCBs at > 16.0 µg/L can impair their immune functions.

Point-of-care detection of 16S rRNA of Staphylococcus aureus based on multiple biotin-labeled DNA probes.

A visual method that combines multiple biotin-labeled DNA probes and lateral-flow nucleic acid biosensor was developed to detect Staphylococcus aureus. The 16S rRNA from Staphyloccocus aureus (S. aureus), coupled with multiple biotin-labeled DNA probes, was functionalized in a signal structure for lateral-flow point-of-care detection. The secondary structure of the 16S rRNA was unwound by two specific capture probes modified by Fam and multiple bridge probes, which extended additional sequences for use as initiators. By utilizing the initiators, each target 16S rRNA with multiple DNA probes could tether a number of biotin molecules, so that a large number of streptavidin-labeled gold nanoparticles could be introduced in the lateral flow assay. The images of the lateral flow detection results obtained using a smartphone were transmitted to a computer via Wi-Fi or Bluetooth connection for quantitative processing by ImageJ. The limit of detection was 103 cfu/mL without sample enrichment, and decreased to 0.12 cfu/mL following a 3-h enrichment of samples in growth medium. Notably, this method presented high specificity and applicability for the detection of S. aureus in food samples. In short, the developed visual non-specific operation method is very suitable for point-of-care diagnosis of pathogens in resource-limited countries.

Single-Cell Resolution of Uncultured Magnetotactic Bacteria via Fluorescence-Coupled Electron Microscopy.

Magnetotactic bacteria (MTB) form intracellular chain-assembled nanocrystals of magnetite or greigite termed magnetosomes. The characterization of magnetosome crystals requires electron microscopy due to their nanoscopic sizes. However, electron microscopy does not provide phylogenetic information for MTB. We have developed a strategy for the simultaneous and rapid phylogenetic and biomineralogical characterization of uncultured MTB at the single-cell level. It consists of four steps: (i) enrichment of MTB cells from an environmental sample, (ii) 16S rRNA gene sequencing of MTB, and (iii) fluorescence in situ hybridization analyses coordinated with (iv) transmission or scanning electron microscopy of the probe-hybridized cells. The application of this strategy identified a magnetotactic Gammaproteobacteria strain, SHHR-1, from brackish sediments collected from the Shihe River estuary in Qinhuangdao City, China. SHHR-1 magnetosomes are elongated prismatic magnetites which can be idealized as hexagonal prisms. Taxonomic groups of uncultured MTB were also identified in freshwater sediments from Lake Miyun in northern Beijing via this novel coordinated fluorescence and scanning electron microscopy method based on four group-specific rRNA-targeted probes. Our analyses revealed that major magnetotactic taxonomic groups can be accurately determined only with coordinated scanning electron microscopy observations on fluorescently labeled single cells due to limited group coverage and specificity for existing group-specific MTB fluorescence in situ hybridization (FISH) probes. Our reported strategy is simple and efficient, offers great promise toward investigating the diversity and biomineralization of MTB, and may also be applied to other functional groups of microorganisms.IMPORTANCE Magnetotactic bacteria (MTB) are phylogenetically diverse and biomineralize morphologically diverse magnetic nanocrystals of magnetite or greigite in intracellular structures termed magnetosomes. However, many uncultured MTB strains have not been phylogenetically identified or structurally investigated at the single-cell level, which limits our comprehensive understanding of the diversity of MTB and their role in biomineralization. We developed a fluorescence-coupled electron microscopy method for the rapid phylogenetic and biomineralogical characterization of uncultured MTB at the single-cell level. Using this novel method, we successfully identified taxonomic groups of several uncultured MTB and one novel magnetotactic Gammaproteobacteria strain, SHHR-1, from natural environments. Our analyses further indicate that strain SHHR-1 forms elongated prismatic magnetites. Our findings provide a promising strategy for the rapid characterization of phylogenetic and biomineralogical properties of uncultured MTB at the single-cell level. Furthermore, due to its simplicity and generalized methodology, this strategy can also be useful in the study of the diversity and biomineralization properties of microbial taxa involved in other mineralization processes.

Colorimetric detection of microRNA based hybridization chain reaction for signal amplification and enzyme for visualization.

MicroRNAs (miRNAs) have key roles in gene expression and can be employed as biomarkers for early diagnosis of various diseases, especially cancers. Detection of miRNAs remains challenging and often requires detection platforms. Here, a horseradish peroxidase (HRP)-assisted hybridization chain reaction (HCR) for colorimetric detection of miR-155 was described. In the presence of target miRNA, the capture probe immobilized on the microplate sandwiched the target miR-155 with the 3' end of the reporter probe. Another exposed part of the RP at the 5'end triggered HCR producing double-stranded DNA polymers with multiple fluorescein isothiocyanates (FITC) for signal amplification. Finally, multiple HRP molecules were immobilized onto the long-range DNA nanostructures through FITC/anti-FITC monoclonal antibody interactions on the microplate for visualization by tetramethylbenzidine/H2O2 system and the colorless substrate turned into the blue product. To obtain accurate data, the absorbance at 450 nm was calculated by microplate reader. The detection limit was 31.8 fM (3.18 amol). Furthermore, this biosensor showed high specificity and was able to discriminate sharply between target miRNA and mismatched sequences. And this approach could be easily applied to the detection of miR-155 in serum sample, thereby ascribing it for a wide application.

Nectar properties and the role of sunbirds as pollinators of the golden-flowered tea (Camellia petelotii).

PREMISE OF THE STUDY: Properties of floral nectar have been used to predict if a plant species is pollinated by birds. To see whether winter-flowering plants evolve nectar properties corresponding to bird pollinators, nectar properties of several Camellia species (including the golden-flowered tea), as well as the role of floral visitors as effective pollinators, were examined. METHODS: Potential pollinators of Camellia petelotii were identified at different times of day and under various weather conditions. A bird exclusion experiment was used to compare the pollination effectiveness of birds and insects. Nectar sugar components (fructose, glucose, and sucrose) from C. petelotii growing wild and another seven Camellia species and 22 additional cultivars (all in cultivation) were examined by high-performance liquid chromatography (HPLC). KEY RESULTS: The sunbird Aethopyga siparaja and honeybees were the most frequent floral visitors to C. petelotii. Honeybee visits were significantly reduced in cloudy/rainy weather. The fruit and seed set of flowers with birds excluded were reduced by 64%, indicating that bird pollination is significant. For the wild populations of C. petelotii, a bagged flower could secrete 157 µL nectar; this nectar has a low sugar concentration (19%) and is sucrose-dominant (87%). The eight Camellia species and 22 cultivars had an average sugar concentration of around 30% and a sucrose concentration of 80%, demonstrating sucrose-dominant nectar in Camellia species. CONCLUSIONS: The nectar sugar composition of Camellia species was characterized by sucrose dominance. In addition, the large reduction in seed set when birds are excluded in the golden-flowered tea also supports the suggestion that these winter-flowering plants may have evolved with birds as significant pollinators.

Use of Redundant Exclusion PCR To Identify a Novel Bacillus thuringiensis Cry8 Toxin Gene from Pooled Genomic DNA.

UNLABELLED: With the aim of optimizing the cloning of novel genes from a genomic pool containing many previously identified homologous genes, we designed a redundant exclusion PCR (RE-PCR) technique. In RE-PCR, a pair of generic amplification primers are combined with additional primers that are designed to specifically bind to redundant, unwanted genes that are a subset of those copied by the amplification primers. During RE-PCR, the specific primer blocks amplification of the full-length redundant gene. Using this method, we managed to clone a number of cry8 or cry9 toxin genes from a pool of Bacillus thuringiensis genomic DNA while excluding amplicons for cry9Da, cry9Ea, and cry9Eb The method proved to be very efficient at increasing the number of rare genes in the resulting library. One such rare (and novel) cry8-like gene was expressed, and the encoded toxin was shown to be toxic to Anomala corpulenta IMPORTANCE: Protein toxins from the bacterium Bacillus thuringiensis are being increasingly used as biopesticides against a wide range of insect pests, yet the search for new or improved toxins is becoming more difficult, as traditional methods for gene discovery routinely isolate previously identified clones. This paper describes an approach that we have developed to increase the success rate for novel toxin gene identification through reducing or eliminating the cloning of previously characterized genes.

Screening, characterization and mechanism of a potential stabiliser for nisin nanoliposomes with high encapsulation efficiency.

The encapsulation efficiency (EE%) reflects the amount of bioactive components that can be loaded into nanoliposomes. Obtaining a suitable nanoliposome stabiliser may be the key to improving their EE%. In this study, three polyphenols were screened as stabilisers of nanoliposomes with high nisin EE%, with curcumin nanoliposomes (Cu-NLs) exhibiting the best performance (EE% = 95.94%). Characterizations of particle size, PDI and zeta potential indicate that the Cu-NLs had good uniformity and stability. TEM found that nisin accumulated at the edges of the Cu-NLs' phospholipid layer. DSC and FT-IR revealed that curcumin was involved in the formation of the phospholipid layer and altered its structure. FT-IR and molecular docking simulations indicate that the interactions between curcumin and nisin are mainly hydrogen bonding and hydrophobic. In whole milk, Cu-NLs effectively protected nisin activity. This study provides an effective strategy for improving the EE% of nanoliposomes loaded with nisin and other bacteriocins.

Porcine epidemic diarrhea virus E protein induces formation of stress granules and attenuates protein translation through activation of the PERK/eIF2α signaling pathway.

Porcine epidemic diarrhea virus (PEDV) envelope protein (E) has been characterized as an important structural protein that plays critical roles in the interplay with its host to affect the virus life cycle. Stress granules (SGs) are host translationally silent ribonucleoproteins, which are mainly induced by the phosphorylation of eIF2α in the PERK/eIF2α signaling pathway. Our previous study found that PEDV E protein caused endoplasmic reticulum stress response (ERS)-mediated suppression of antiviral proteins' translation. However, the link and the underlying mechanism by which PEDV induces SGs formation and suppresses host translation remain elusive. In this study, our results showed that PEDV E protein significantly elevated the expression of GRP78, CANX, and phosphorylation of PERK and eIF2α, indicating that the PERK/eIF2α branch of ERS was activated. PEDV E protein localized to the ER and aggregated into puncta to reconstruct ER structure, and further induced SGs formation, which has been caused through upregulating the G3BP1 expression level. In addition, a significant global translational stall and endogenous protein translation attenuation were detected in the presence of E protein overexpression, but the global mRNA transcriptional level remained unchanged, suggesting that the shutoff of protein translation was associated with the translation, not with the transcription process. Collectively, this study demonstrates that PERK/eIF2α activation is required for SGs formation and protein translation stall. This study is beneficial for us to better understand the mechanism by which PEDV E suppresses host protein synthesis, and provides us a new insight into the host translation regulation during virus infection.

Suppressive effects of fisetin on mice T lymphocytes in vitro and in vivo.

BACKGROUND: Most of the immunosuppressive drugs have satisfactory therapeutic effects on organ transplantation and autoimmune disease. However, their clinical application is limited by side effects. Therefore, new and safe immunosuppressive drugs against acute and chronic rejections are eagerly awaited. Fisetin, a flavonoid present in various types of vegetables and fruits, has few side effects and low level of toxicity, which would be a desirable clinical feature. In the present study, we investigated the immunosuppressive effects and underlying mechanisms of fisetin against T-cell activation in vitro and in vivo. METHODS: We measured the effect of fisetin on T-lymphocyte proliferation, T-cell subsets, cell cycle progression, cytokine production, and nuclear factor activation in vitro, as well as its influence on T cell-mediated delayed-type hypersensitivity reaction in vivo. RESULTS: In vitro, the results showed that fisetin significantly suppressed mouse splenocytes proliferation, Th1 and Th2 cytokine production, cell cycle and the ratio of CD4(+)/CD8(+) T cells. Furthermore, fisetin exerts an immunosuppressive effect in mouse T lymphocytes through the suppression of nuclear factor kappa B activation and nuclear factor of activated T cells signaling in a dose-dependent manner. In vivo, fisetin treatment also significantly inhibited the dinitrofluorobenzene-induced delayed-type hypersensitivity reactions in mice. CONCLUSIONS: Fisetin had strong immunosuppressive activity in vitro and in vivo, suggesting a potential role for fisetin as an immunosuppressive agent.

Rhodotorula mucilaginosa ZTHY2 Attenuates Cyclophosphamide-Induced Immunosuppression in Mice.

Rhodotorula mucilaginosa (R. mucilaginosa) can enhance the immune and antioxidant function of the body. However, whether R. mucilaginosa has an immunoregulatory effect on cyclophosphamide (CTX)-induced immunosuppressed animals remains to be clarified. In this study, the R. mucilaginosa ZTHY2 that we isolated from the coastal waters of the South China Sea previously was prepared in order to investigate its immunoprotective effect on CTX-induced immunosuppression in mice, and the effects were compared to those of Lactobacillus acidophilus (LA) (a well-known probiotic). Seventy-two male SPF mice were divided into six groups: The C group (control); IM group (immunosuppressive model group) (+CTX); Rl, Rm, and Rh groups (+CTX+low, medium, and high concentration of R. mucilaginosa, respectively); and PC (positive control) group (+CTX+LA). After a 28-day feeding trial, blood samples were taken for biochemical and serum immunological analysis, and the thymus and spleen were collected to analyze the organ index, lymphocyte proliferation and differentiation, and antioxidant capacity. The findings showed that R. mucilaginosa ZTHY2 improved the spleen and thymus indices, effectively attenuated immune organ atrophy caused by CTX, and enhanced the proliferation of T and B lymphocytes induced by ConA and LPS. R. mucilaginosa ZTHY2 promoted the secretion of cytokines and immunoglobulins and significantly increased the contents of IL-2, IL-4, IL-6, TNF-α, IFN-γ, IgA, IgG, IgM, CD4, CD8, CD19, and CD20 in serum. The proportion of CD4+, CD8+, CD19+, and CD20+ lymphocytes in spleen, thymus, and mesenteric lymph nodes were increased. In addition, R. mucilaginosa ZTHY2 reduced the reactive oxygen species (ROS) and malondialdehyde (MDA) levels and increased glutathione (GSH), total superoxide dismutase (SOD), and catalase (CAT) levels. Our results indicated that R. mucilaginosa ZTHY2 can significantly enhance the immune function of immunosuppressed mice, and improving antioxidant capacity thus attenuates CTX-induced immunosuppression and immune organ atrophy.

Preparation, characterization and application of bacteriocin CAMT6 nanoliposomes using resveratrol as a novel stabilizer.

Nanoliposomes are ideal nanocarriers for encapsulated active compounds used in the food industry as they provide stability and controlled release. However, cholesterol may pose risks in large intake, which is the commonly-used nanoliposome stabilizers. In this study, resveratrol was used instead of cholesterol as a novel nanoliposome stabilizer to construct a resveratrol blank liposome (RBL) system. The RBL system was used to protect the bacteriocin CAMT6 to create bacteriocin-loaded nanoliposomes (BLLs). The RBLs and BLLs had favourable particle sizes (172.71 nm and 150.47 nm), polydispersity index (PDI) values (0.150 and 0.120) and zeta potentials (-41.54 mV and -43.53 mV, respectively). According to Differential scanning colourimetry (DSC) and X-ray diffraction (XRD) analyses, resveratrol altered the structure of the phospholipid layer. The phospholipid layers of the RBLs and BLLs had higher mobility when resveratrol was used as a stabilizer instead of cholesterol. Structurally, resveratrol was inserted egg yolk lecithin to constitute an RBL. CAMT6 was loaded in BLLs with spherical and shell-core structures. The BLL encapsulation efficiency was 97.32 % and exhibited three release phases, with the release rates reaching 62 %. In experiments with milk, the BLLs effectively protected the anti-Listeria activity of CAMT6. In summary, resveratrol is a suitable nanoliposome stabilizer and the proposed RBL system is an excellent way to improve the stability of water-soluble preservatives, such as bacteriocins, in complex food environments.

Isolation and genomic characterization of Klebsiella Lw3 with polychlorinated biphenyl degradability.

Bioremediation of sediment organic pollution has been intensely investigated, but the degradation of complex organic compounds, pesticide residues, and polychlorinated biphenyls (PCBs) remains poorly studied. In this study, sediments were collected from Zhanjiang Mangrove Reserve and inoculated in an inorganic salt medium using only biphenyl (BP) and PCBs as the carbon sources to obtain a PCB-degrading strain. A gram-negative bacterium that metabolized PCBs was isolated and identified as Klebsiella Lw3 by 16S rDNA phylogenetic analysis. Genomic sequencing showed that this bacterium possessed genes related to BP/PCB degradation, and its GC content was 58.2%; we identified 3326 cellular pathways. Gas chromatography-mass spectrometry was employed to test the PCB degrading ability; the results showed that the strain had a good degradation effect on PCB3 at concentrations of 5, 10, 20, 40, and 60 mg/L and that the final degradation rate was higher than 97% after 96 h. Interestingly, this strain showed good biodegradability of PCBs despite having no classical PCB degradation pathway, providing a new direction for Klebsiella research with practical significance for in situ bioremediation of PCB contamination. Overall, this study provides valuable insights into the genetic structure of PCB-degrading strains as well as eco-friendly and low-cost PCB degradation and lays a foundation for the discovery of new degradation pathways.

PrPSc Inhibition and Cellular Protection of DBL on a Prion-Infected Cultured Cell via Multiple Pathways.

Prion diseases are kinds of fatal neurodegenerative diseases without effective therapeutic and prophylactic tools currently. In this study, the inhibition of PrPSc propagation and cellular protectivity of 3,4-dihydroxybenzalacetone (DBL), a small catechol-containing compound isolated and purified from the ethanol extract of Inonotus obliquus, upon a prion-infected cell line SMB-S15 were evaluated. Western blots showed that after incubation with 10 µM of DBL for 14 days, the level of PrPSc in SMB-S15 cells was significantly decreased. Meanwhile, the levels of ROS and hydrogen peroxide were decreased with a dose-dependent manner, whereas the levels of some antioxidant factors, such as HO-1, GCLC and GCLM, were significantly increased. The activities of total glutathione and SOD were up-regulated. DBL-treated SMB-S15 cells also showed the up-regulation of UPR-related proteins, including PERK, IRE1α, ATF6 and GRP78, and activation of autophagy system. Furthermore, the SIRT3 abnormalities caused by prion infection were relieved by DBL treatment. On the contrary, these comprehensive changes were not significantly noticed in the normal partner cell line SMB-PS under the same experimental condition. Those data indicate that treatment of DBL on prion-infected cells can reduce PrPSc level, activate UPR and autophagy system and meanwhile relieve intracellular oxidative stress, endoplasmic reticulum stress and mitochondrial dysfunction by raising the levels of multiple antioxidant factors. The PrPSc inhibition and protective effectiveness of DBL upon the prion-infected cells in vitro make it worthy of further study.

Triterpenoids as bivalent and dual inhibitors of acetylcholinesterase/butyrylcholinesterase from the fruiting bodies of Inonotus obliquus.

Inonotus obliquus, an edible and medicinal mushroom parasitic on birches, has been used in human diet and for traditional therapies in the high latitude regions of Europe and Asia for a long time. Our phytochemical study of this fungus led to the identification of fourteen triterpenoids including four undescribed ones, and two pairs of undescribed phenolic enantiomers. The undescribed compounds were elucidated by extensive spectroscopic analysis including 1D and 2D NMR and HRESIMS, quantum chemical NMR and ECD calculations, as well as single-crystal X-ray diffraction analysis. Bioassays revealed that eight compounds showed dual inhibition against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) with IC50 values ranging from 2.40 ± 0.05 to 28.72 ± 0.46 µM, while 3ß-hydroxy-lanosra-8,24-dien-21-al and trametenolic acid only presented BuChE inhibitory activities with IC50 values of 22.21 ± 1.01 and 7.68 ± 0.13 µM, respectively. In the kinetic studies, the most active three compounds acted as non-competitive inhibitors for both cholinesterases. Furthermore, molecular docking simulations revealed that three compounds demonstrated dual-sites bounding to AChE/BuChE. These triterpenoids emerged as bivalent and dual inhibitors of AChE/BuChE and could be effective drug candidates to prevent and treat Alzheimer's disease in the future.

Different Aberrant Changes of mGluR5 and Its Downstream Signaling Pathways in the Scrapie-Infected Cell Line and the Brains of Scrapie-Infected Experimental Rodents.

Metabotropic glutamate receptor subtype 5 (mGluR5) is a G-protein-coupled receptor found widely in the central nervous system. It has been involved in the development and progression of some neurodegenerative diseases, but its role in prion diseases is rarely described. In this study, the changes of mGluR5 and its downstream signaling pathways in prion-infected cell line SMB-S15 and the brains of scrapie-infected experimental rodents were evaluated by various methodologies. We found the levels of mGluR5 were significantly increased in a prion-infected cell line SMB-S15 and the cultured cells transiently express an abnormal form PrP (Cyto-PrP). Using immunoprecipitation tests and immunofluorescent assays (IFA), molecular interaction and morphological colocalization between PrP and mGluR5 were observed in the cultured cells. We identified that the (GPCRs)-IP3-IP3R-Ca2+ pathway was activated and the levels of the downstream kinases p38, ERK, and JNK were increased in SMB-S15 cells. After treated with mGluR5 antagonist (MTEP) or the removal of prion replication by resveratrol in SMB-S15 cells, the upregulations of mGluR5 and the downstream kinases were restored in a certain degree. Moreover, increased mGluR5 contributes to the cell damage in prion-infected cells. Contrarily, the levels of mGluR5 in the brains of several scrapie-infected rodent models were decreased at terminal stage. IFA of the brain sections of scrapie-infected rodents demonstrated that the signals of mGluR5 were preferentially colocalized with the NeuN-positive cells, accompanying with severe neuron losses in Nissl staining, which might be a reason for the decrease of mGluR5. Our data indicate the different aberrant alterations of mGluR5 and the downstream signaling pathways during prion infection in vivo and in vitro.