Underestimation about the Contribution of Nitrate Reducers to Iron Cycling Indicated by Enterobacter Strain.

Nitrate-reducing iron(II) oxidation (NRFO) has been intensively reported in various bacteria. Iron(II) oxidation is found to be involved in both enzymatic and chemical reactions in nitrate-reducing Fe(II)-oxidizing microorganisms (NRFOMs). However, little is known about the relative contribution of biotic and abiotic reactions to iron(II) oxidation for the common nitrate reducers during the NRFO process. In this study, the typical nitrate reducers, four Enterobacter strains E. hormaechei, E. tabaci, E. mori and E. asburiae, were utilized as the model microorganisms. The comparison of the kinetics of nitrate, iron(II) and nitrite and N2O production in setups with and without iron(II) indicates a mixture of enzymatic and abiotic oxidation of iron(II) in all four Enterobacter strains. It was estimated that 22-29% of total oxidized iron(II) was coupled to microbial nitrate reduction by E. hormaechei, E. tabaci, E. mori, and E. asburiae. Enterobacter strains displayed an metabolic inactivity with heavy iron(III) encrustation on the cell surface in the NRFOmedium during days of incubation. Moreover, both respiratory and periplasmic nitrate-reducing genes are encoded by genomes of Enterobacter strains, suggesting that cell encrustation may occur with periplasmic iron(III) oxide precipitation as well as the surface iron(II) mineral coating for nitrate reducers. Overall, this study clarified the potential role of nitrate reducers in the biochemical cycling of iron under anoxic conditions, in turn, re-shaping their activity during denitrification because of cell encrustation with iron(III) minerals.

[Theory of "synchronization of heaven-qi, earth-qi and human-qi" in Zhuang Medicine and its application in acupuncture and moxibustion].

The connotation of theory of "synchronization of heaven-qi, earth-qi and human-qi " in Zhuang Medicine is introduced, and its association with human physiological state, pathological changes and acupuncture treatment mechanism are discussed. The main points, acupuncture manipulation and clinical acupoint selection of acupuncture and moxibustion of Zhuang Medicine are guided by this theory. The points are mainly composed of Huan points, Luoyang points and experience-based points, which are divided into heaven part, earth part and human part according to the positions in the human body. The acupuncture manipulation is divided into mild manipulation, moderate manipulation and heavy manipulation according to heaven, earth and human theory. With the point prescriptions for headache, dysmenorrhea and herpes zoster sore as examples, the application of this theory in the clinical acupoint selection is explained.

Host age increased conjugal plasmid transfer in gut microbiota of the soil invertebrate Caenorhabditis elegans.

Plasmid conjugation contributes greatly to the spread of antibiotic resistance genes (ARGs) in soils. However, the spread potential in the gut of soil fauna remains poorly studied, and little was known about the impact of host age on ARGs dissemination in the gut microbiota of soil animals. Here, the typical nematode-Caenorhabditis elegans was employed as the model soil animal, aiming to investigate transfer of broad-host-range IncP-1ɛ from Escherichia coli MG1655 to gut microbiota within 6 days under varied temperature gradients (15, 20 and 25 °C) using qPCR combined with plate screening. Results showed that conjugation rates increased with incubation time and rising temperature in the gut of C. elegans, sharing a similar trend with abundances of plasmid conjugation relevant genes such as trbBp (mating pair formation) and trfAp (plasmid replication). Incubation time and temperature significantly shaped the gut microbial community of C. elegans. Core microbiota in the gut of C. elegans, including Enterobacteriaceae, Lactobacillaceae and Leuconostocaceae, constituted a large part of transconjugal pool for plasmid IncP-1ɛ. Our results highlight an important sink of gut microbiota for ARGs dissemination and upregulation of ARGs transfer in the gut microbiota with host age, further potentially stimulating evolution of ARGs in terrestrial environments.

Co-effect of cadmium and iron oxide nanoparticles on plasmid-mediated conjugative transfer of antibiotic resistance genes.

Conjunctive transfer of antibiotic resistance genes (ARGs) among bacteria driven by plasmids facilitated the evolution and spread of antibiotic resistance. Heavy metal exposure accelerated the plasmid-mediated conjunctive transfer of ARGs. Nanomaterials are well-known adsorbents for heavy metals removal, with the capability of combatting resistant bacteria/facilitating conjunctive transfer of ARGs. However, co-effect of heavy metals and nanomaterials on plasmid-mediated conjunctive transfer of ARGs was still unknown. In this study, we investigated the effect of the simultaneous exposure of Cd2+ and nano Fe2O3 on conjugative transfer of plasmid RP4 from Pseudomonas putida KT2442 to water microbial community. The permeability of bacterial cell membranes, antioxidant enzyme activities and conjugation gene expression were also investigated. The results suggested that the combination of Cd2+ and high concentration nano Fe2O3 (10 mg/L and 100 mg/L) significantly increased conjugative transfer frequencies of RP4 plasmid (p < 0.05). The most transconjugants were detected in the treatment of co-exposure to Cd2+ and nano Fe2O3, the majority of which were identified to be human pathogens. The mechanisms of the exacerbated conjugative transfer of ARGs were involved in the enhancement of cell membrane permeability, antioxidant enzyme activities, and mRNA expression levels of the conjugation genes by the co-effect of Cd2+ and nano Fe2O3. This study confirmed that the simultaneous exposure to Cd2+and nano Fe2O3 exerted a synergetic co-effect on plasmid-mediated conjunctive transfer of ARGs, emphasizing that the co-effect of nanomaterials and heavy metals should be prudently evaluated when combating antibiotic resistance.

Development of an optimized risk score to predict short-term death among acute myocardial infarction patients in rural China.

BACKGROUND: Risk stratification of patients with acute myocardial infarction (AMI) is of great clinical significance. HYPOTHESIS: The present study aimed to establish an optimized risk score to predict short-term (6-month) death among rural AMI patients from China. METHODS: We enrolled 6581 AMI patients and extracted relevant data. Patients were divided chronologically into a derivation cohort (n = 5539), to establish the multivariable risk prediction model, and a validation cohort (n = 1042), to validate the risk score. RESULTS: Six variables were identified as independent predictors of short-term death and were used to establish the risk score: age, Killip class, blood glucose, creatinine, pulmonary artery systolic pressure, and percutaneous coronary intervention treatment. The area under the ROC curve (AUC) of the optimized risk score was 0.82 within the derivation cohort and 0.81 within the validation cohort. The diagnostic performance of the optimized risk score was superior to that of the GRACE risk score (AUC 0.76 and 0.75 in the derivation and validation cohorts, respectively; p < .05). CONCLUSION: These results indicate that the optimized scoring method developed here is a simple and valuable instrument to accurately predict the risk of short-term mortality in rural patients with AMI.

Cadmium enhances conjugative plasmid transfer to a fresh water microbial community.

Co-selection of antibiotic resistance genes (ARGs) by heavy metals might facilitate the spread of ARGs in the environments. Cadmium contamination is ubiquitous, while, it remains unknown the extent to which cadmium (Cd2+) impact plasmid-mediated transfer of ARGs in aquatic bacterial communities. In the present study, we found that Cd2+ amendment at sub-inhibitory concentration significantly increased conjugation frequency of RP4 plasmid from Pseudomonas putida KT2442 to a fresh water microbial community by liquid mating method. Cd2+ treatment (1-100 mg/L) significantly increased the cell membrane permeability and antioxidant activities of conjugation mixtures. Amendments of 10 and 100 mg/L Cd2+ significantly enhanced the mRNA expression levels of mating pair formation gene (trbBp) and the DNA transfer and replication gene (trfAp) due to the repression of regulatory genes (korA, korB and trbA). Phylogenetic analysis of transconjugants indicated that Proteobacteria was the dominant recipients and high concentration of Cd2+ treatment resulted in expanded recipient taxa. This study suggested that sub-inhibitory Cd2+ contamination would facilitate plasmid conjugation and contributed to the maintenance and spread of plasmid associated ARGs, and highlighted the urgent need for effective remediation of Cd2+ in aquatic environments.

Effect of Elevated Pulmonary Artery Systolic Pressure on Short-Term Prognosis in Patients With Acute Myocardial Infarction.

Pulmonary artery systolic pressure (PASP) may increase because of cardiac alterations that result in increased filling pressures after acute myocardial infarction (AMI). We hypothesized that PASP might be a useful maker to predict the risk of cardiac death after AMI. We carried out a retrospective study from 2013 to 2017 involving 5401 patients with AMI. Patients were grouped according to their admission PASP result, and the primary end point was cardiac death in 6 months after AMI. Pulmonary artery systolic pressure was associated with age, AMI site, Killip classification, and decreased ejection fraction. After adjustments for clinical and echocardiographic parameters in a Cox model, PASP was found to be significantly related to cardiac death. In receiver operating characteristic analysis, PASP >30 mm Hg had a sensitivity of 59.8% and a specificity of 62.5% for predicting 6-month cardiac death after AMI. In conclusion, PASP at the index admission may be a useful marker predicting short-term cardiac death. These results have implications for future research and management of patients with AMI.

[Brief analysis on Fuhuan point of Zhuang medicine and clinical application].

Fuhuan point of Zhuang medicine is a set of point distributed as circle form, it is a common point in Zhuang medicine. In this paper, Fuhuan point of Zhuang medicine was analyzed from the following five aspects, i.e. basic theory, location, affiliation to heaven, earth and human being, main usage and principles of point combinations. Zhuang medicine believes that the Fuhuan point is located in the middle of human body, where the essence of heaven and earth converges. Fuhuan point is closely connected with dragon and fire systems as well as zang-fu organs in Zhuang medicine, it acts on promoting circulation, adjusting qi and blood, and treating various diseases. It is highly valuable in clinical application.

Fate of Antibiotic Resistant Pseudomonas putida and Broad Host Range Plasmid in Natural Soil Microcosms.

Plasmid conjugation is one of the dominant mechanisms of horizontal gene transfer, playing a noticeable role in the rapid spread of antibiotic resistance genes (ARGs). Broad host range plasmids are known to transfer to diverse bacteria in extracted soil bacterial communities when evaluated by filter mating incubation. However, the persistence and dissemination of broad range plasmid in natural soil has not been well studied. In this study, Pseudomonas putida with a conjugative antibiotic resistance plasmid RP4 was inoculated into a soil microcosm, the fate and persistence of P. putida and RP4 were monitored by quantitative PCR. The concentrations of P. putida and RP4 both rapidly decreased within 15-day incubation. P. putida then decayed at a significantly lower rate during subsequent incubation, however, no further decay of RP4 was observed, resulting in an elevated RP4/P. putida ratio (up to 10) after 75-day incubation, which implied potential transfer of RP4 to soil microbiota. We further sorted RP4 recipient bacteria from the soil microcosms by fluorescence-activated cell sorting. Spread of RP4 increased during 75-day microcosm operation and was estimated at around 10-4 transconjugants per recipient at the end of incubation. Analysis of 16S rRNA gene sequences of transconjugants showed that host bacteria of RP4 were affiliated to more than 15 phyla, with increased diversity and shift in the composition of host bacteria. Proteobacteria was the most dominant phylum in the transconjugant pools. Transient transfer of RP4 to some host bacteria was observed. These results emphasize the prolonged persistence of P. putida and RP4 in natural soil microcosms, and highlight the potential risks of increased spread potential of plasmid and broader range of host bacteria in disseminating ARGs in soil.