Urbanization influenced the interactions between dissolved organic matter and bacterial communities in rivers.

Increased urbanization and anthropogenic activities can alter dissolved organic matter (DOM) and complicate its interaction with bacteria in rivers' ecosystems, however, there is limited information about how bacterial communities respond to DOM components in rivers with different urbanization levels. Here, we combined spectroscopy-based DOM analysis and 16S rRNA gene amplicon sequencing to investigate the associations of bacterial taxa and DOM properties as well as the impacts of DOM on bacterial niche breadth in North River (NR) and West River (WR) of Jiulong River watershed, southern China, which had low and high urbanization levels, respectively. Spectroscopy analysis showed that hydrophilic DOM was predominant in both rivers whereas chromophoric DOM was higher in WR. Network analysis indicated that only seven bacterial genera (i.e., hg clade, chthoniobacter, Geobacter, Acidibacter, Alphal Cluster, Fluviicola, and Lacunisphaera) showed strong associations with DOM optical variables in both rivers, whereas more than 85% of DOM-bacterial genera associations were different between rivers. These results suggest that the relationship between DOM and bacterial communities had different responses in rivers with different urbanization levels. The partial least square path model indicated that the total standardized effect of physico-chemicals on bacterial niche breadth was higher in NR (0.62) than in WR (0.35), whereas humic substances showed an opposite pattern (NR: -0.42; WR: 1.67). The distinct effects of physico-chemicals and DOM on bacterial niche breadths between rivers could be due to the different effects of urbanization and human activities on the environmental conditions of riverine ecosystems. Our findings revealed a huge dissimilarity in the bacteria-DOM co-occurrence networks between rivers with different urbanization levels and provide a novel insight that urbanization may enhance DOM's importance to bacterial niche breadths.

Impact of high-sensitivity troponin as a selection criterion for healthy people on the reference range of N-terminal pro-B-type natriuretic peptide / 中华检验医学杂志

Objective:The 97.5th percentile upper reference limit (97.5th URL) of N-terminal prob-type natriuretic peptide (NT-proBNP) is influenced by multiple factors and depends on the inclusion criteria of apparently healthy people. In this study, the reference upper limit of NT-proBNP was established on apparently healthy people in Beijing area with abnormal hs-cTn as the exclusion criterion.Methods:According to the latest expert consensus recommendation standards of natriuretic peptide in the detection and clinical application of heart failure published by the Clinical Application Group of Cardiac Bio-Markers of the International Union of Clinical Chemistry, 1 635 healthy people without abnormal appearance of routine indicators such as sex, age, glycated hemoglobin, estimated glomerular filtration rate and medical history were collected. After excluding participants with potential myocardial injury according to hs-cTnI and/or hs-cTnT concentration>99th URL, NT-proBNP 97.5th URL was established in healthy subjects aged 21-40 years ( n=205), 41-50 years ( n=535), 51-60 years ( n=556) and >60 years ( n=339) based on non-parametric statistics. Results:The level of NT-proBNP was positively correlated with age ( r=0.254, P<0.001). The levels of NT-proBNP were positively correlated with hs-cTnI, hs-cTnT in males ( r=0.377 and r=0.429, both P<0.001). The levels of NT-proBNP were also positively correlated with hs-cTnI, hs-cTnT in females ( r=0.132 and r=0.296, both P<0.001). When hs-cTn>99th URL was used as the criterion to exclude patients with potential myocardial injury, among apparently healthy people aged 21-40 years old, 41-50 years old, 51-60 years old and >60 years old, male NT-proBNP 97.5th URL was 81.9 (90% CI 60.0-588.8), 141.2 (90% CI 100.0-263.6), 272.0 (90% CI 193.0-494.0) and 547.9 (90% CI 311.2-738.6), respectively; For females, the rates were 227.5 (90% CI 81.9-360.8), 153.2 (90% CI 128.2-239.5), 300.6 (90% CI 211.0-376.4) and 395.8 (90% CI 242.3-543.5) ng/L, respectively. Conclusions:This study confirmed that hs-cTn>99th URL can be used as an apparent population screening criterion for natriuretic peptide reference interval studies, which is helpful to remove conventional means to include individuals with occult myocardial injury in apparently healthy patients, so as to establish a more rigorous healthy cohort and establishing solid normal NT-proBNP reference interval.