Microbial induced carbonate precipitation (MICP) is a common occurrence of geochemistry influences in many fields, such as biological, geographical, and engineering systems. However, the processes that control interactions between carbonate biomineralization and biofilm properties are poorly understood. We develop a method for real time, in situ and nondestructive imaging with confocal scanning microscopy. This method provides a possible way to observe biomineralization process and the morphology of biomineralized deposits within biofilms. We use this method to show calcite biominerals produced by Pseudomonas aeruginosa biofilms which extremely change biofilm structures. The distribution of calcite precipitation produced in situ biomineralization is highly heterogeneous in biofilms and also to occur primarily on the bottom of biofilms. It is distinct from those usual expectations that mineral started to precipitate from surface of biofilm. Our results reveal that biomineralization plays a comprehensive regulation function on biofilm architecture and properties.Electronic supplementary materialThe online version of this article (doi:10.1186/s13568-017-0358-5) contains supplementary material, which is available to authorized users.

Domestic wastewater was treated by five constructed wetland beds in series. Dissolved organic matter (DOM) collected from influent and effluent samples from the constructed wetland was investigated using fluorescence spectroscopy combined with fluorescence regional integration (FRI), parallel factor (PARAFAC) analysis, and two-dimensional correlation spectroscopy (2D-COS). This study evaluates the capability of these methods in detecting the spectral characteristics of fluorescent DOM fractions and their changes in constructed wetlands. Fluorescence excitation-emission matrix (EEM) combined with FRI analysis showed that protein-like materials displayed a higher removal ratio compared to humic-like substances. The PARAFAC analysis of wastewater DOM indicated that six fluorescent components, i.e., two protein-like substances (C1 and C6), three humic-like substances (C2, C3 and C5), and one non-humic component (C4), could be identified. Tryptophan-like C1 was the dominant component in the influent DOM. The removal ratios of six fluorescent components (C1-C6) were 56.21, 32.05, 49.19, 39.90, 29.60, and 45.87 %, respectively, after the constructed wetland treatment. Furthermore, 2D-COS demonstrated that the sequencing of spectral changes for fluorescent DOM followed the order 298 nm → 403 nm → 283 nm (310-360 nm) in the constructed wetland, suggesting that the peak at 298 nm is associated with preferential tryptophan fluorescence removal. Variation of the fluorescence index (FI) and the ratio of fluorescence components indicated that the constructed wetland treatment resulted in the decrease of fluorescent organic pollutant with increasing the humification and chemical stability of the DOM.

Most organisms on Earth possess circadian rhythms in their physiology and behaviors that allow them to resonate with the cycling environment over a 24‐h period. However, in human society, a substantial quantity of jobs requires non–24‐h working and rest or shift schedules, which causes more or less misalignment in circadian rhythms and disorders as a consequence. In this work, we conducted a sleep deprivation (SD) and non–24‐h working and rest schedule (8 h on and 4 h off) experiment over 10 d in total and measured the changes in a series of physiologic and cognitive parameters. The results show that although the subjects could sleep during the schedule, their sleepiness increased significantly. Actigraphy data suggest that a 12‐h schedule might result in chronic SD. Along with the increased sleepiness revealed by the Karolinska Sleepiness Scale questionnaire, the neurobehavioral psychomotor vigilance test data reveal that, compared with the control period, the reaction time of the subjects was significantly delayed. The saliva insulin levels were significantly changed in the morning in SD and non–24‐h cycles. Salivary biochemical parameters were also altered, including aspartate aminotransferase and K+. 16S rRNA‐based analysis of the salivary microbiota showed differentially changed patterns in bacteria composition and concentration. Together, these data demonstrate that an abnormal working and rest schedule might produce comprehensive interference with circadian rhythms, metabolism, and cognition.—Ma, H., Li, Y., Liang, H., Chen, S., Pan, S., Chang, L., Li, S., Zhang, Y., Liu, X., Xu, Y., Shao, Y., Yang, Y., Guo, J. Sleep deprivation and a non–24‐h working schedule lead to extensive alterations in physiology and behavior. FASEB J. 33, 6969–6979 (2019). http://www.fasebj.org

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Environmental contextDissolved organic matter (DOM) plays an important role in influencing the migration and ultimate fate of metals. Different sources of pollution resulted in changes in the structure of sediment DOM in Lake Wuliangsuhai. We investigate the binding properties of DOM with CuII and HgII using fluorescence quenching combined with two-dimensional correlation spectroscopy (2D-COS) in order to demonstrate the influence of different sources of DOM on metals. AbstractDissolved organic matter (DOM) was collected from three sampling sites (L1, L2 and L3) in Lake Wuliangsuhai. L1 received upstream industrial wastewater and domestic sewage. L2 had suffered from agricultural non-point source pollution. L3 was situated in the lake outlet area. The complexation of DOM with CuII and HgII was investigated based on fluorescence quenching of the synchronous fluorescence spectra on the addition of CuII and on two-dimensional correlation spectroscopy (2D-COS). The synchronous and asynchronous maps derived from 2D-COS provided a clear picture of the heterogeneous distribution of CuII and HgII binding sites, which was not readily detected using only the synchronous fluorescence spectra. CuII and HgII complexation was stronger at shorter wavelengths than at longer wavelengths. Moreover, fluorescence quenching also occurred intensely in the fulvic-like regions (363nm for DOM-Cu in L2 and 365nm for DOM-Hg in L1). The logarithms of the stability constants (log KM) ranged from 4.42 to 6.23, from 4.75 to 4.86, and from 4.80 to 5.73 for DOM-Cu in L1, L2 and L3, respectively, depending on the wavelength. DOM at the longer wavelengths exhibited a higher log KM than that at the shorter wavelengths, and the f values in the protein-like region were clearly high. These results suggest that the influence of the structural and chemical properties of DOM on CuII binding may differ for DOM from different sources. The combined approach of fluorescence quenching and 2D-COS could be applied as a tool for evaluating the metal binding site heterogeneity of DOM.

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