Resistance role of Lactobacillus sp. and Lactococcus sp. to copper ions in healthy children's intestinal microorganisms.

Heavy metal exposure is closely associated with gut microbe function and tolerance. However, intestinal microbe responses in children to different copper ion (Cu2+) concentrations have not yet been clarified. Here, in vitro cultivation systems were established for fecal microbe control and Cu2+-treated groups in healthy children. 16S rDNA high-throughput sequencing, meta-transcriptomics and metabolomics were used here to identify toxicity resistance mechanisms at microbiome levels. The results showed that Lactobacillus sp. and Lactococcus sp. exerted protective effects against Cu2+ toxicity, but these effects were limited by Cu2+ concentration. When the Cu2+ concentration was ≥ 4 mg/L, the abundance of Lactobacillus sp. and Lactococcus sp. significantly decreased, and the pathways of antioxidant activity and detoxification processes were enriched at 2 mg/L Cu2+, and beneficial metabolites accumulated. However, at high concentrations of Cu2+ (≥4 mg/L), the abundance of potential pathogen increased, and was accompanied by a downregulation of genes in metabolism and detoxification pathways, which meant that the balance of gut microbiota was disrupted and toxicity resistance decreased. From these observations, we identified some probiotics that are tolerant to heavy metal Cu2+, and warn that only when the concentration limit of Cu2+ in food is 2 mg/L, then a balanced gut microbiota can be guaranteed in children, thereby providing protection for their health.

Catalytic removal of gaseous pollutant NO using CO: Catalyst structure and reaction mechanism.

Carbon monoxide (CO) has recently been considered an ideal reducing agent to replace NH3 in selective catalytic reduction of NOx (NH3-SCR). This shift is particularly relevant in diesel engines, coal-fired industry, the iron and steel industry, of which generate substantial amounts of CO due to incomplete combustion. Developing high-performance catalysts remain a critical challenge for commercializing this technology. The active sites on catalyst surface play a crucial role in the various microscopic reaction steps of this reaction. This work provides a comprehensive overview and insights into the reaction mechanism of active sites on transition metal- and noble metal-based catalysts, including the types of intermediates and active sites, as well as the conversion mechanism of active molecules or atoms. In addition, the effects of factors such as O2, SO2, and alkali metals, on NO reduction by CO were discussed, and the prospects for catalyst design are proposed. It is hoped to provide theoretical guidance for the rational design of efficient CO selective catalytic denitration materials based on the structure-activity relations.

Adsorption abilities and mechanisms of Lactobacillus on various nanoplastics.

As a new type of pollutants, nanoplastics (NPs), which are easily ingested by humans from food wraps, salt, drinking water, have been widely detected in various water environments, and are a threat to human health. It is therefore urgent to develop an efficient method to remove NPs from the diet or relief its harm. In the present study, the possibility of a well-known human probiotic, lactic acid bacteria (LAB), was evaluated to remove NPs from food as an absorbent. The results indicated that LAB from infant feces could efficiently absorb three types NPs, i.e. polypropylene (PP), polyethylene (PE), and polyvinyl chloride (PVC) with the adsorption rates of PP > PE > PVC (PP 78.57%, PE 71.59%, PVC 66.57%) and the Nile red-stained NPs being aggregated on the surfaces of Lactobacillus cells. The smaller the particle size, the stronger the ability of NP adsorption on the cell surface. The hydrophobicity of NPs and bacterial cells affected the adsorption process. The measurement of adsorption rates of different cell components indicated that the overall adsorption effect of cell was better than that of individual cell component. The results of molecular dynamics analysis revealed that adsorption was mainly caused by electrostatic interactions, van der Waals forces, and hydrogen bonds. The hydrophobic interaction was also involved in adsorption process. Overall, this research may provide new information for developing new strategies for NPs removal in intestinal environment.

Gut microbiota mediate melatonin signalling in association with type 2 diabetes.

AIMS/HYPOTHESIS: It has been shown that melatonin plays a general beneficial role in type 2 diabetes in rodents but its role in humans is controversial. In the present study, we investigated the association between serum melatonin and type 2 diabetes risk in a southern Chinese population in a case-control study. We also examined the role of gut microbiota in this relationship. METHODS: Individuals with type 2 diabetes (cases) and healthy individuals (controls) (n=2034) were recruited from a cross-sectional study and were matched for age and sex in a case-control study. The levels of serum melatonin were measured and the association between serum melatonin and type 2 diabetes risk was examined using a multivariable logistic regression model. We further conducted a rigorously matched case-control study (n=120) in which gut microbial 16S rRNA was sequenced and metabolites were profiled using an untargeted LC-MS/MS approach. RESULTS: Higher levels of serum melatonin were significantly associated with a lower risk of type 2 diabetes (OR 0.82 [95% CI 0.74, 0.92]) and with lower levels of fasting glucose after adjustment for covariates (ß -0.25 [95% CI -0.38, -0.12]). Gut microbiota exhibited alteration in the individuals with type 2 diabetes, in whom lower levels of serum melatonin, lower α- and ß-diversity of gut microbiota (p<0.05), greater abundance of Bifidobacterium and lower abundance of Coprococcus (linear discriminant analysis [LDA] >2.0) were found. Seven genera were correlated with melatonin and type 2 diabetes-related traits; among them Bifidobacterium was positively correlated with serum lipopolysaccharide (LPS) and IL-10, whereas Coprococcus was negatively correlated with serum IL-1ß, IL-6, IL-10, IL-17, TNF-α and LPS (Benjamini-Hochberg-adjusted p value [false discovery rate (FDR)] <0.05). Moreover, altered metabolites were detected in the participants with type 2 diabetes and there was a significant correlation between tryptophan (Trp) metabolites and the melatonin-correlated genera including Bifidobacterium and Coprococcus (FDR<0.05). Similarly, a significant correlation was found between Trp metabolites and inflammation factors, such as IL-1ß, IL-6, IL-10, IL-17, TNF-α and LPS (FDR<0.05). Further, we showed that Trp metabolites may serve as a biomarker to predict type 2 diabetes status (AUC=0.804). CONCLUSIONS/INTERPRETATION: A higher level of serum melatonin was associated with a lower risk of type 2 diabetes. Gut microbiota-mediated melatonin signalling was involved in this association; especially, Bifidobacterium- and Coprococcus-mediated Trp metabolites may be involved in the process. These findings uncover the importance of melatonin and melatonin-related bacteria and metabolites as potential therapeutic targets for type 2 diabetes.

Dietary variety relates to gut microbiota diversity and abundance in humans.

PURPOSE: We aim to investigate the relationship between gut microbiota and dietary variety in a Chinese population using Dietary Variety Score (DVS), an index of dietary variety, as little has studied the relationship of dietary variety and gut microbiota in a general population. METHODS: In this cross-sectional study, recruited participants were conducted with face-to-face interview to collect information on 24-h food intake and dietary consumption using a valid food frequency questionnaire. Subjects (n = 128) were divided as high and low DVS groups by the median of DVS after rigorously matching for confounding factors. The gut microbiota was assessed by 16S rRNA sequencing and the correlations between key phylotypes and DVS, Index of Nutritional Quality (INQ) and clinical indices were examined using generalized linear model in negative binomial regression. RESULTS: Higher score of DVS, INQVB6, INQVE and INQZn exhibited higher α-diversity. DVS was correlated with INQ and six genera. Among the DVS-correlated genera, Turicibacter, Alistipes and Barnesiella were positively correlated with INQVE, INQZn and INQCu, individually or in combination, while Cetobacterium was negatively correlated with INQCu, INQZn and INQVE. The abundance of Coprococcus and Barnesiella increased with the elevated cumulative scores of INQVE, INQVB6 and INQZn. The combination of Alistipes, Roseburia and Barnesiella could moderately predict dietary variety status. CONCLUSION: Higher DVS was correlated with higher microbial diversity and more abundance of some potentially beneficial bacteria but with less some potentially pathogenic bacteria. A high variety dietary, therefore, should be recommended in our daily life.

Correlation of CCL8 expression with immune cell infiltration of skin cutaneous melanoma: potential as a prognostic indicator and therapeutic pathway.

BACKGROUND: The tumor microenvironment (TME) is critical in the progression and metastasis of skin cutaneous melanoma (SKCM). Differences in tumor-infiltrating immune cells (TICs) and their gene expression have been linked to cancer prognosis. Given that immunotherapy can be effective against SKCM, we aimed to identify key genes that regulate the immunological state of the TME in SKCM. METHODS: Data from 471 SKCM patients in the The Cancer Genome Atlas were analyzed using ESTIMATE algorithms to generate an ImmuneScore, StromalScore, and EstimateScore for each patient. Patients were classified into low- or high-score groups based on median values, then compared in order to identify differentially expressed genes (DEGs). Then a protein-protein interaction (PPI) network was developed, and a prognostic model was created using uni- and multivariate Cox regression as well as the least absolute shrinkage and selection operator (LASSO). Key DEGs were identified using the web-based tool GEPIA. Profiles of TIC subpopulations in each patient were analyzed using CIBORSORT, and possible correlations between key DEG expression and TICs were explored. Levels of CCL8 were determined in SKCM and normal skin tissue using immunohistochemistry. RESULTS: Two scores correlated positively with the prognosis of SKCM patients. Comparison of the low- and high-score groups revealed 1684 up-regulated and 18 down-regulated DEGs, all of which were enriched in immune-related functions. The prognostic model identified CCL8 as a key gene, which CIBERSORT found to correlate with M1 macrophages. Immunohistochemistry revealed strong expression in SKCM tissue, but failed to detect the protein in normal skin tissue. CONCLUSIONS: CCL8 is a potential prognostic marker for SKCM, and it may become an effective target for melanoma in which M1 macrophages play an important role.

Neonatal Weight and Prenatal Exposure to Polychlorinated Biphenyls: A Meta-Analysis.

BACKGROUND: This research studied the relationship between maternal exposure to polychlorinated biphenyls and neonatal birth weight through systematic review and meta-analysis of existing literature. METHODS: We searched for all the studies published in MEDLINE / PUBMEDN / EMBASE (Medical Abstract Database) by June 2018, and seven studies had been selected. RESULTS: The results showed that there was significant correlation between birth weight reduction and PCBS exposure throughout pregnancy (ß=-0.586g, 95%CI:-0.629,-0.543). There was a negative correlation between birth weight and PCBs exposure and umbilical cord serum (ß=-0.833g) and maternal serum (ß= -0.504g).Subgroup analyses showed significantly different effects of PCBs exposure on birth weight in different regions, stages of pregnancy and study designs. It was thought the heterogeneity was mainly caused by geographical regions, stages of pregnancy, and the assessment methods. CONCLUSION: The meta analysis revealed a negative correlation between PCBs exposure and birth weight but there was significant difference in the correlation between birth weight loss.

[Construction of anti-H5N1 virus chimeric igA antibody gene and its expression in CHO cells].

Abstract: To express human-mouse chimeric IgA antibody directed against H5N1 virus, an anti-H5N1 chimeric IgA antibody gene was constructed by joining the light and heavy chain variable region genes and the corresponding signal peptide coding sequences of the anti-H5N1 mouse monoclonal antibody H5N1-HA with the coding sequences of the constant region of the human IgA2 heavy chain and Kappa chain respectively. Then the full-length chimeric light and heavy chain expressing plasmids pEF-IGHA9 and pEF-IGK9 were constructed and transfected into the CHO/dhfr cells. The chimeric IgA antibody expression was confirmed by ELISA, SDS-PAGE and Western blotting. The successful expression of this anti-H5N1 chimeric IgA may help to provide a stand for developing passive immunological agents for H5N1 virus infection prophylaxis.

Clinicopathological study on TTV infection in hepatitis of unknown etiology.

AIM: To investigate the state of infection, replication site, pathogenicity and clinical significance of transfusion transmitted virus (TTV) in patients with hepatitis, especially in patients of unknown etiology. METHODS: Liver tissues taken from 136 cases of non-A non-G hepatitis were tested for TT virus antigen and nucleic acid by in situ hybridization (ISH) and nested-polymerase chain reaction (PCR). Among them, TT virus genome and its complemental strand were also detected in 24 cases of autopsy liver and extrahepatic tissues with ISH. Meanwhile, TTV DNA was detected in the sera of 187 hepatitis patients by nested-PCR. The pathological and clinical data of the cases infected with TTV only were analyzed. RESULTS: In liver, the total positive rate of TTV DNA was 32.4% and the positive signals were located in the nuclei of hepatocytes. In serus, TTV DNA was detected in 21.4% cases of hepatitis A-G, 34.4% of non-A non-G hepatitis and 15% of healthy donors. The correspondence rate of TTV DNA detection between liver tissue with ISH and sera with PCR was 63.2% and 89.3% in the same liver tissues by ISH and by PCR, respectively. Using double-strand probes and single-strand probes designed to detect TTV genome, the correspondence rate of TTV DNA detected in liver and extrahepatic tissues was 85.7%. Using single-strand probes, TTV genome could be detected in liver and extrahepatic tissues by PCR, but its complemental strands (replication strands) could be observed only in livers. The liver function of most cases infected with TTV alone was abnormal and the liver tissues had different pathological damage such as ballooning, acidophilia degeneration, formation of apoptosis bodies and focus of necrosis, but the inflammation in the lobule and portal area was mild. CONCLUSION: The positive rate of TTV DNA among cases of hepatitis was higher than that of donors, especially in patients with non-A non-G hepatitis, but most of them were coinfected with other hepatitis viruses. TTV can infect not only hepatocytes, but also extrahepatic tissues. However, the chief replication place may be liver. The infection of TTV may have some pathogenicity. Although the pathogenicity is comparatively weak, it can still damage the liver tissues. The lesions in acute hepatitis (AH) and chronic hepatitis (CH) are mild, but in severe hepatitis (SH), it can be very serious and cause liver function failure, therefore, we should pay more attention to TTV when studying the possible pathogens of so-called "liver hepatitis of unknown etiology".

[Selection and characterization of peptides that specifically binding to hepatitis C virus serine protease].

The HCV NS3 serine protease that plays important role in the processing of polyprotein and the replication of virus is a prime target for antiviral drugs and therapy research. Based on the crystallographic structure of HCV sreine protease, a single-chain protease was contstructed in which the central sequence of NS4A was fused to the N-terminus of NS3 serine protease domain via a flexible linker and it was expressed at high level in soluble form in E. coli. The purified protease could cleave the recombinant protein NS5ab into two parts. The purified protease was used as target to screen binding peptides from phage displayed peptide library. After three rounds of affinity screening, 37 out of 44 randomly selected phages could bind specifically with the single-chain serine protease and their specificity were verified by competitive ELISA. The 13 sequenced clones represents 6 kinds of sequences of which the amino acids composition is in bias and there is a consensus sequence: [H/F/W]-H-W-X-X-W.

Construction of Human Immunoglobulin Combinatorial Library and Screening of Phage Antibodies to Hepatitis B Surface Antigen.

Human immunoglobulin combinatorial library was generated by using phage surface-display expression system, and phage antibodies (Fab fragments) to hepatitis B surface antigen (HbsAg) were screened from it. The products by half-nested PCR using signal peptide sequences as primers were superior in quality and quantity to those by PCR with conserved sequences in the 5'-end variable regions as primers. After three round of selections by biopanning, the ratio of positive clone was 69%. The inhibition assay showed the phage antibodies to be specifically anti-HbsAg. The V(H) genes were derived from V(H) I and V(H) III, while V(L)s belonged to V(lambda) II and V(lambda) I as shown by DNA sequencing.