Heterogeneous photo-Fenton catalyst α-Fe2O3@g-C3N4@NH2-MIL-101(Fe) with dual Z-Scheme heterojunction for degradation of tetracycline.

A novel photo-Fenton catalyst α-Fe2O3@g-C3N4@NH2-MIL-101(Fe) (FGN) with dual Z-scheme heterojunction was successfully prepared by hydrothermal method to degrade tetracycline (TC). The preparation conditions were optimized by orthogonal test, and the successful synthesis was confirmed by characterization analyses. The prepared FGN showed better light absorption performance, higher photoelectrons-holes separation efficiency, lower photoelectrons transfer resistance, and higher specific surface area and pore capacity compared with α-Fe2O3@g-C3N4 and α-Fe2O3. The effects of experimental conditions on the catalytic degradation of TC were investigated. The degradation rate of 10 mg/L TC could reach 98.33% within 2 h when the dosage of FGN was 200 mg/L, and the degradation rate could remain 92.27% after 5 times of reuse. Furthermore, the XRD spectra and XPS spectra of FGN before and after reuse were compared to explore the structural stability and catalytic active sites of FGN, respectively. According to the identification of oxidation intermediates, three degradation pathways of TC were proposed. Through H2O2 consumption experiment, radical-scavenging experiments, EPR results, the mechanism of the dual Z-scheme heterojunction was proved. The improved performance of FGN was attributed to the dual Z-Scheme heterojunction effectively promoting the separation of photogenerated electrons from the holes and accelerating the electrons transfer, and the increase of the specific surface area.

Pathways and biological mechanisms of N2O emission reduction by adding biochar in the constructed wetland based on 15N stable isotope tracing.

Constructed wetlands (CWs) added with biochar were built to study pollutant removal efficiencies, nitrous oxide (N2O) emission characteristics, and biological mechanisms in nitrogen transformation. The results showed that biochar addition enhanced the average removal rates of ammonium (NH4+-N), total nitrogen, and chemical oxygen demand by 4.03-18.5%, 2.90-4.99%, and 2.87-5.20% respectively while reducing N2O emissions by 25.85-83.41%. Based on 15N stable isotope tracing, it was found that nitrification, denitrification, and simultaneous nitrification and denitrification were the main processes contributing to N2O emission. The addition of biochar resulted in maximum reduction rates of 71.50%, 80.66%, and 73.09% for these three processes, respectively. The relative abundance of nitrogen-transforming microbes, such as Nitrospira, Dechloromonas, and Denitratisoma, increased after the addition of biochar, promoting nitrogen removal and reducing N2O emissions. Adding biochar could increase the functional gene copy number and enzyme activity responsible for nitrogen conversion, which helped achieve efficient NH4+-N oxidation and eliminate nitrite accumulation, thereby reducing N2O emissions.

LDH as an adjuvant makes Brucella outer-membrane vesicles and outer-membrane vesicle-associated proteins highly protective in mice.

Objectives: Existing Brucella vaccines are attenuated and can cause vaccine-associated brucellosis; and these safety concerns have affected their application. Although subunit vaccines have the advantages of safety, efficacy, low cost, and rapid production, they are usually poorly immunogenic and insufficient to trigger persistent immunity. Therefore, we added layered double hydroxide (LDH) as an adjuvant to Brucella subunit vaccine formulations to enhance the immune response to the antigen. Materials and Methods: LDH and Freund's adjuvant were combined with Brucella outer-membrane vesicles (OMVs) and OMV-associated proteins to form a subunit vaccine, respectively. The immunogenicity of LDH as an adjuvant was assessed in BALB/c mice. We examined levels of immunoglobulin G, G1, and G2a (IgG, IgG1, and IgG2a) antibodies (aBs); percentages of Cluster of Differentiation 4-positive (CD4+) and CD8+ T cells in peripheral-blood lymphocytes; and secretion of cytokines in mouse spleen lymphocytes. Finally, splenic index and splenic bacterial load were assessed via Brucella challenge experiments on mice. Results: The LDH subunit vaccine also produced high levels of specific aBs in mice compared with Freund's adjuvant subunit vaccine and induced mainly T-helper 1 cell (Th1)-type immune responses. In addition, mice in the LDH subunit vaccine group had significantly lower bacterial loads in their spleens than those in the Freund's adjuvant subunit vaccine group, and the LDH-OMV vaccine offered a higher level of protection against Brucella attack. Conclusion: LDH as an adjuvant-paired vaccine provided a high level of protection against Brucella infection.

Preoperative α-blockade versus no blockade for pheochromocytoma-paraganglioma patients undergoing surgery: a systematic review and updated meta-analysis.

BACKGROUND: Surgical resection of pheochromocytomas and paragangliomas (PPGLs) is associated with a significant risk of intraoperative hemodynamic instability and cardiovascular complications. α-blockade remains the routine preoperative medical preparation despite controversies over the lack of evidence. We presented an updated meta-analysis to ulteriorly evaluate the potential efficacy of preoperative α-blockade versus no blockade for PPGL patients undergoing surgery. MATERIALS AND METHODS: Randomized and nonrandomized comparative studies assessing preoperative α-blockade for PPGL surgery in adults were identified through a systematic literature search via MEDLINE, Embase, Web of Science, and CENTRAL up to November 2022. Outcome data of intraoperative hemodynamic parameters and major postoperative events were extracted. Mean difference and risk ratio were synthesized as appropriate for each outcome to determine the cumulative effect size. RESULTS: Fifteen nonrandomized studies involving 3542 patients were finally eligible. Intraoperatively, none of the analyzed hemodynamic parameters differed between patients with or without α-blockade: maximum and minimum systolic blood pressure, hypertensive and hypotensive hemodynamic instability episodes, and peak heart rate, subgroup analysis of normotensive PPGL patients yielded similar results with the overall effects. Postoperatively, α-blockade was associated with prolonged hypotension and vasopressor usage (risk ratio: 4.21, 95% CI: 1.17-15.18, P =0.03). ICU admission, length of stay, overall cardiovascular morbidity, and mortality were similar between the two groups. CONCLUSIONS: Preoperative α-blockade ensured neither more stable intraoperative hemodynamics nor better perioperative outcome over no blockade for PPGL surgery. However, large-volume randomized controlled trials are still warranted to ascertain these findings.

A SARS-CoV-2 nanobody that can bind to the RBD region may be used for treatment in COVID-19 in animals.

Coronavirus disease 2019 (COVID-19) caused by an infectious virus, severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), poses a threat to the world. The suitable treatments must be identified for this disease in animals. Nanobody have therapeutic potential in the COVID-19. In this study, SARS-CoV-2 Spike RBD protein was used to make the nanobody. Nanobodies binding to the SARS-CoV-2 Spike RBD protein was obtained. Interestingly, the nanobody could bind to SARS-CoV-2 Spike S protein and RBD protein at the same time. Nanobodies were validated with a neutralizing antibody detection kit. The use of pseudoviruses confirmed that nanobodies could prevent pseudoviruses from infecting cells. We believe the nanobody are very valuable and could be used in the treatment of COVID-19. SARS-CoV-2 nanobodies can be rapidly mass-produced from microorganisms to block SARS-CoV-2 infection in vitro and in vivo with preventive and therapeutic effects.

Deletion of the type IV secretion system promoter VirB in Brucella abortus A19 strain attenuated the virulence of the bacteria and promotes autophagy.

Brucella abortus is a gram-negative intracellular parasite bacteria that causes serious health hazards in humans and animals. The type IV secretion system (T4SS), encoded by the virB promoter, has been identified as an important virulence factor for Brucella abortus, but its impact on Brucella abortus A19 remains unclear. In this study, the T4SS of Brucella abortus A19 was inactivated by deletion of the virB promoter, resulting in a mutant strain A19ΔvirB. Real-time PCR and western blotting analysis demonstrated that T4SS-related proteins were not expressed after virB promoter deletion. Moreover, the survival rate of A19 in high-salt and strong acidic environments decreased after virB promoter deletion. Compared to the parental strain A19, the A19ΔvirB mutant strain showed reduced growth rate in TSB, decreased invasion ability to macrophages and dendritic cells, and reduced virulence of the mutant strain in macrophages, dendritic cells, and mice. In addition, the A19ΔvirB mutant strain showed enhanced autophagy in macrophages and dendritic cells compared with A19, and the A19ΔvirB mutant strain was able to upregulate IL-6 and downregulate IL-10 in macrophages. These data help us to better understand the T4SS of the A19 vaccine strain and contribute to our efforts to improve Brucella vaccines.

Screening and evaluation of Mycobacterium tuberculosis diagnostic antigens.

In recent years, the prevalence of tuberculosis worldwide has increased, and with it, the number of drug-resistant tuberculosis strains. This has brought new challenges towards prevention and control of the disease. Therefore, it is urgent to find reliable and rapid diagnostic methods for tuberculosis in general, and for the drug-resistant forms of the disease. To this aim, we assessed 17 tuberculosis-specific protein candidates for the detection of tuberculosis-specific antibodies. First, we established an indirect ELISA method to detect anti-Mycobacterium tuberculosis IgM and IgG. We tested 453 sera and analyzed the efficacy of the protein candidates for diagnosis of tuberculosis. Next, we screened antigens rich in T cell epitopes for their ability to induce high levels of IFN-γ, in order to define their suitability does develop detection tests based on IFN-γ release assay (IGRAs). The antigens CFP-10, PPE57, 38kDa, and Rv3807 showed higher diagnostic potential for the detection of anti-tuberculosis IgM, whereas PPE57, Ag85B, CFP-10, Rv0220, and 38kDa antigens performed better for anti-tuberculosis IgG detection. Worth noting is that CFP-10, 38kDa, and PPE57 detected efficiently both IgM and IgG. Rv1987, Rv3807, PPE57, Rv0220, and MPT64 proteins alone and combinations of Rv1987 + Rv3807, 16kDa + Rv0220, and MPT64 + Rv1986 tested in IGRAs displayed a good correlation with the positive control constituted by a cocktail of ESAT-6 + CFP-10 + TB7.7 (ECT), known for their stimulating properties (r > 0.5, p < 0.01). Among these antigen candidates, Rv0220 and Rv1987 + Rv3807 were the most potent. We discovered CFP-10, 38kDa, and PPE57 for the detection of anti-M. tuberculosis IgM and IgG, and Rv0220 alone or the combination Rv1987 + Rv3807 as the strongest stimulators in IGRAs. These antigens provide new references for the screening of tuberculosis-specific antibodies and effective stimulation in IGRAs.

Interaction between Brucella melitensis 16M and small ubiquitin-related modifier 1 and E2 conjugating enzyme 9 in mouse RAW264.7 macrophages.

Brucella is an intracellular pathogen that invades a host and settles in its immune cells; however, the mechanism of its intracellular survival is unclear. Modification of small ubiquitin-related modifier (SUMO) occurs in many cellular activities. E2 conjugating enzyme 9 (Ubc9) is the only reported ubiquitin-conjugating enzyme that links the SUMO molecule with a target protein. Brucella's intracellular survival mechanism has not been studied with respect to SUMO-related proteins and Ubc9. Therefore, to investigate the relationship between Brucella melitensis 16M and SUMO, we constructed plasmids and cells lines suitable for overexpression and knockdown of SUMO1 and Ubc9 genes. Brucella 16M activated SUMO1/Ubc9 expression in a time-dependent manner, and Brucella 16M intracellular survival was inhibited by SUMO1/Ubc9 overexpression and promoted by SUMO1/Ubc9 depletion. In macrophages, Brucella 16M-dependent apoptosis and immune factors were induced by SUMO1/Ubc9 overexpression and restricted by SUMO1/Ubc9 depletion. We noted no effect on the expressions of SUMO1 and Ubc9 in B. melitensis 16M lipopolysaccharide-prestimulated mouse RAW264.7 macrophages. Additionally, intracellular survival of the 16M△VirB2 mutant was lower than that of Brucella 16M (p < 0.05). VirB2 can affect expression levels of Ubc9, thereby increasing intracellular survival of Brucella in macrophages at the late stage of infection. Collectively, our results demonstrate that B. melitensis 16M may use the VirB IV secretion system of Brucella to interact with SUMO-related proteins during infection of host cells, which interferes with SUMO function and promotes pathogen survival in host cells.

microRNA-34a and microRNA-34c promote the activation of human hepatic stellate cells by targeting peroxisome proliferator-activated receptor γ.

Liver fibrosis is the common outcome of almost all cases of chronic liver disease. The hallmark of liver fibrosis is the activation of hepatic stellate cells (HSCs). microRNA­34a (miR­34a), which regulates a plethora of target proteins involved in the cell cycle, apoptosis, differentiation and cellular development, is found to be upregulated in both activated HSCs and liver fibrosis, while it is consistently downregulated in numerous cancer types. In the present study, the possible mechanisms underlying the role of miR­34a and miR­34c in the activation of the HSCs was investigated. Through bioinformatics analysis and a luciferase reporter assay, five genes were identified to be the target genes of miR­34a and miR­34c. Of these, peroxisome proliferator­activated receptor γ (PPARγ) was selected for further investigation. Mutation luciferase reporter assay confirmed the direct interaction of PPARγ and miR­34a and miR­34c. Western blot analysis and quantitative polymerase chain reaction demonstrated that the expression of PPARγ was negatively correlated with the expression of miR­34a and miR­34c during the activation of HSCs. In activated human HSCs, inhibitors of miR­34a and miR­34c upregulated the expression of PPARγ and downregulated the expression of α­smooth muscle actin. These data suggested that the miR­34 family may be involved the process of liver fibrosis by targeting PPARγ.

microRNAs: novel players in hepatitis C virus infection.

Hepatitis C virus (HCV) is a single-stranded, positive-sense RNA virus. About 70% of patients exposed to HCV develop a chronic infection, which can lead to scarring of the liver and ultimately to cirrhosis, liver failure, and hepatocellular carcinoma. For the past decade, the standard therapy for HCV infection has been a combination of interferon-α and ribavirin. In recent years, direct-acting antiviral agents, boceprevir and telaprevir, have been added to the therapeutic regimen and considerably improve the cure rates for HCV infection. However, the treatment continues to cause substantial side effects and is associated with drug resistance due to frequent mutations in the HCV RNA genome resulting from the low fidelity of its RNA polymerase. MicroRNAs (miRNAs) are a class of small, non-coding RNAs approximately 22 nucleotides in length. They are derived from cellular or viral transcripts and bind to their target mRNAs in a sequence-specific manner, resulting in either mRNA cleavage or translational repression and subsequent modulation of the expression of the majority of the protein-coding genes. miRNAs have been implicated in regulating multiple aspects of HCV life cycles and certain miRNAs serve as essential mediators for the interferon-based antiviral therapy. Furthermore, recent studies have documented the potential values of miRNAs as novel therapeutic targets against hepatitis C infectivity.

Association between the c.3751G>a genetic variant of MDR1 and hepatocellular carcinoma risk in a Chinese Han population.

The objective of this study was to evaluate the influence of a genetic variant in the multidrug resistance 1 gene (MDR1) on hepatocellular carcinoma (HCC) risk. This case-control study was conducted in a Chinese population of 645 HCC cases and 658 cancer-free controls. The genotype of the c.3751G>A genetic variant in the MDR1 gene was investigated by created restriction site-polymerase chain reaction (CRS-PCR) and DNA sequencing methods. Our data demonstrated significantly differences detected in the allelic and genotypic frequencies between HCC cases and those of cancer-free controls. Association analyses indicated that there were statistically increased risk of HCC in the homozygote comparison (AA versus (vs.) GG: OR = 2.22, 95% CI 1.51-3.27, χ(2) = 16.90, P < 0.001), dominant model (AA/GA vs. GG: OR = 1.25, 95% CI 1.00-1.55, χ(2) = 3.98, P = 0.046), recessive model (AA vs. GA/GG: OR = 2.14, 95% CI 1.47-3.09, χ(2) = 16.68, P < 0.001) and allele comparison (A vs. G: OR = 1.33, 95% CI 1.13-1.57, χ(2) = 11.66, P = 0.001). The allele-A and genotype-AA may contribute to HCC susceptibility. These preliminary findings suggest that the c.3751G>A genetic variant in the MDR1 gene is potentially related to HCC susceptibility in a Chinese Han population, and might be used as a molecular marker for evaluating HCC susceptibility.

Enhancement of invasion of hepatocellular carcinoma cells through lysophosphatidic acid receptor.

OBJECTIVES: Lysophosphatidic acid (LPA) is a bioactive lipid mediator involved in tumour progression, cell invasion and metastasis. The mechanism of action of LPA in the invasive and metastatic capacity of human hepatocellular carcinoma (HCC) is not fully understood. This study investigated the effects of LPA on HCC cell invasion and induction of matrix metalloproteinase (MMP) -2 and -9. METHODS: LPA receptor levels in HCC cell lines were detected by Western blot analysis; HCC cell invasion was analysed by the Transwell® system. The LPA receptor blocker Ki16425 was used to determine whether HCC cell invasion was LPA dependent. Expression of the MMP2 and MMP9 genes in HCC cells was determined by real-time quantitative reverse transcription-polymerase chain reaction (qPCR). RESULTS: LPA increased HCC cell invasion, which was LPA-receptor dependent. Real-time RT-qPCR showed that LPA increased MMP9, but not MMP2, expression in HCC cells. Pharmacological inhibition of LPA receptors with Ki16452 significantly attenuated LPA-induced HCC cell invasion. CONCLUSIONS: HCC invasiveness is facilitated by LPA and may be relevant to tumour progression. Thus, LPA receptors may be a potential therapeutic target for HCC.

Ardipusilloside inhibits survival, invasion and metastasis of human hepatocellular carcinoma cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Ardipusilloside I is a triterpene-saponin isolated from the Traditional Chinese Medicine Ardisia pusilla A. DC. Its effects and mechanism on invasion and metastasis of liver cancer cells are unclear. MATERIALS AND METHODS: The human hepatocellular carcinoma cell line HepG2 and SMMC-7721 cells were treated with different doses of Ardipusilloside I. Cellular survival, in vitro migration and invasion were evaluated. In vivo metastatic abilities of the HCC cells were detected. We further investigated expression and phosphorylation of Mek, Erk and Akt by using Western blot. MMP2 and MMP9 activities were evaluated by gelatin zymography. E-cadherin expression, Rac1 and Cdc42 activities were examined by Western blot and pull-down assay. RESULTS: Ardipusilloside I inhibited invasion and metastasis of HCC cells both in vitro and in vivo by reducing the protein expressions of metalloproteinase (MMP)-9 and MMP2 proteins. Ardipusilloside I activated Rac1 that enhanced E-cadherin activity and resulted in significantly less metastasis. CONCLUSION: Our findings indicate that Ardipusilloside I has the potential of inhibition of liver cancer survival, invasion and metastasis both in vitro and in vivo.