A vast diversity of microbes colonizes in the human gastrointestinal tract, referred to intestinal microbiota. Microbiota and products thereof are indispensable for shaping the development and ...function of host innate immune system, thereby exerting multifaceted impacts in gut health.
This paper reviews the effects on immunity of gut microbe-derived nucleic acids, and gut microbial metabolites, as well as the involvement of commensals in the gut homeostasis. We focus on the recent findings with an intention to illuminate the mechanisms by which the microbiota and products thereof are interacting with host immunity, as well as to scrutinize imbalanced gut microbiota (dysbiosis) which lead to autoimmune disorders including inflammatory bowel disease (IBD), Type 1 diabetes (T1D) and systemic immune syndromes such as rheumatoid arthritis (RA).
In addition to their well-recognized benefits in the gut such as occupation of ecological niches and competition with pathogens, commensal bacteria have been shown to strengthen the gut barrier and to exert immunomodulatory actions within the gut and beyond. It has been realized that impaired intestinal microbiota not only contribute to gut diseases but also are inextricably linked to metabolic disorders and even brain dysfunction.
A better understanding of the mutual interactions of the microbiota and host immune system, would shed light on our endeavors of disease prevention and broaden the path to our discovery of immune intervention targets for disease treatment.
•Constructed wetland configuration, TN purification and mechanisms are discussed.•Biochemical process is the main pathway to remove TN in ammonia-dominant wastewater.•Nitrification-denitrification in ...CW needs large O2 and COD consumption in sequence.•Simultaneous nitrification-denitrification can use spatial heterogeneity of biofilm.•Anammox process can save the chemical cost but needs accurate condition control.
Constructed wetland (CW) for wastewater treatment has attracted increasing attention. In this review, the system configuration optimization, purification effect and general mechanisms of nitrogen removal in CW are systematically summarized and discussed. Ammonia oxidation is a crucial and primary process for total nitrogen (TN) removal in domestic or livestock wastewater treatment. Aeration, waterdrop influent and tidal operation are three main methods to strengthen the oxygen supplement and nitrification process in CW. Aeration significantly increases the ammonia removal rate (almost 100%), followed by the removal of chemical oxygen demand (COD) and TN. Solid carbon source, iron and anode material can be filled as electron donor for the denitrification process. The co-adjustment of oxygen and carbon/electron donor can form different conditions for different nitrogen removal pathways (e.g. the simultaneous nitrification-denitrification, the partial nitrification-denitrification and the anammox process), and achieve the optimal removal of nitrogen.
Alternative splicing is a tightly regulated biological process by which the number of gene products for any given gene can be greatly expanded. Genomic variants in splicing regulatory sequences can ...disrupt splicing and cause disease. Recent developments in sequencing technologies and computational biology have allowed researchers to investigate alternative splicing at an unprecedented scale and resolution. Population-scale transcriptome studies have revealed many naturally occurring genetic variants that modulate alternative splicing and consequently influence phenotypic variability and disease susceptibility in human populations. Innovations in experimental and computational tools such as massively parallel reporter assays and deep learning have enabled the rapid screening of genomic variants for their causal impacts on splicing. In this review, we describe technological advances that have greatly increased the speed and scale at which discoveries are made about the genetic variation of alternative splicing. We summarize major findings from population transcriptomic studies of alternative splicing and discuss the implications of these findings for human genetics and medicine.
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•Non-suspended microalgae achieve easy biomass recovery and high stress resistance.•TN and TP could get a 90% removal with load rate higher than 150 mg·L−1·d−1.•Above 70% TN and TP ...were transferred from wastewater to microalgae biomass.•The dynamic growth of non-suspended microalgae determined the pollutant removal rate.•The mechanism of pollutant transfer and microalgae growth require investigation.
Non-suspended microalgae cultivation technology coupled with wastewater purification has received more scientific attention in recent decades. Since the non-suspended microalgae cultivation is quite different from the suspended ones, the following issues are compared in this study such as advantages and disadvantages, pollutant removal mechanisms and regulations, influential factors, and microalgae biomass accumulation. The analysis aims to support the further application of this technology. The median removal rates of COD, TN, TP, NH4+-N and NO3−-N were 91.6%, 78.2%, 87.5%, 93.2% and 81.7%, respectively, by non-suspended microalgae under the TN & TP load rates up to 150 mg·L−1·d−1. The main pathway for TN & TP removal is microalgae cell absorbance. Light intensity, pollutant composition and microalgae metabolic types are the major factors that influence pollutant removal and the lipid content of microalgae. Meanwhile the mechanism concerning how macro-outer conditions influence the micro-environment and further growth of non-suspended microalgae requires more investigation.
Various techniques for the determination of nitrite and/or nitrate developed during the past 15 years were reviewed in this article. 169 references were covered. The detection principles and ...analytical parameters such as matrix, detection limits and detection range of each method were tabulated. The advantages and disadvantages of various methods were evaluated. In comparison to other methods, spectrofluorimetric methods have become more attractive due to its facility availability, high sensitivity and selectivity, low limits of detection and low-cost.
Various techniques for the determination of nitrite and/or nitrate developed during the past 15 years were reviewed in this article. 169 references were covered. The detection principles and analytical parameters such as matrix, detection limits and detection range of each method were tabulated. The advantages and disadvantages of various methods were evaluated. In comparison to other methods, spectrofluorimetric methods have become more attractive due to its facility availability, high sensitivity and selectivity, low limits of detection and low-cost. Display omitted
•Various techniques for the determination of nitrite and/or nitrate are reviewed.•The detection principles and analytical parameters of each method are tabulated.•The advantages and disadvantages of various methods are evaluated.
Microalgae is considered an alternative source for biodiesel production producing renewable, sustainable and carbon-neutral energy. Microalgae property changes among species, which determines the ...efficiency of biodiesel production. Besides the lipid content evaluation, multi-principles (including high lipid productivity, high biomass yield, pollution resistance and desired fatty acid, etc.) for superior oil-producing species screening was proposed in this review and three microalgae species (Chlorella vulgaris, Scenedesmus obliquus and Mychonastes afer) with high bio-lipid producing prospect were screened out based on big data digging and analysis. The multilateral strategies for algal-lipid stimulating were also compared, among which, nutrient restriction, temperature control, heterotrophy and chemicals addition showed high potential in enhancing lipid accumulation; while electromagnetic field showed little effect. Interestingly, it was found that the lipid accumulation was more sensitive to nitrogen (N)-limitation other than phosphorus (P). Nutrient restriction, salinity stress etc. enhanced lipid accumulation by creating a stressed environment. Hence, optimum conditions (e.g. N:15–35 mg/L and P:4–16 mg/L) should be set to balance the lipid accumulation and biomass growth, and further guarantee the algal-lipid productivity. Otherwise, two-step cultivation could be applied during all the stressed stimulation. Different from lab study, effectiveness, operability and economy should be all considered for stimulation strategy selection. Nutrient restriction, temperature control and heterotrophy were highly feasible after the multidimensional evaluation.
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•A multi-factor evaluation is proposed to screen algal species for lipid production.•Mychonastes with excellent bio-lipid property is promising but often neglected.•The characters of lipid stimulating strategies are systematically compared.•Nutrient starvation, temperature control and heterotrophy were relatively feasible.•Lipid accumulation is more sensitive to nitrogen stimulating rather than phosphorus.
Attached microalgae cultivation could simplify the microalgae harvest process and reduce its associated cost, which has attracted much attention recently. In this paper, the reactor patterns, ...advantages, microalgae biomass productivity, influencing factors and the microalgae physicochemical properties in the attached microalgae cultivation was summarized to show the sketch of this novel microalgae cultivation. It was concluded that the attached microalgae cultivation is advantageous in achieving less water and space consumption, higher water treatment potential and higher biomass productivity compared with the traditional suspended microalgae cultivation. The accumulation of the attached microalgae biomass showed a linear increase with culture time with the largest productivity up to 20.7 g m−2 d−1. Chlorella and Scenedesmus were the top two species that have been studied in attached culture system. Cellulose acetate/nitrate membrane, polycarbonate membrane and cotton were the most popular materials used owing to their high hydrophilicity and wide availability. Flow rate, nutrients, light, CO2 and other factors could affect the attached microalgae productivity and the physicochemical property in a way different from the suspended microalgae, which were described in detail in this review. At last, some technical bottlenecks and the corresponding solvents in the attached microalgae were suggested.
•Attached cultivation could simplify microalgae harvest process and reduce its cost.•Attached microalgae showed a linear growth with the rate up to 20.7 g m−2 d−1.•Algae species, support media and nutrients affected attached microalgae growth.•Physicochemical property and their influence factors varied with culture patterns.
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•Fe addition in partially unsaturated CW could achieve high TN/TP removal (＞75%).•Extra biochar addition decreased Fe dosage but achieved the equivalent TN/TP removal.•Electron ...generation and transport by Fe-C enhanced denitrification to above 95%.•Fe-metabolic bacteria and electroactive bacteria were enriched by Fe-C addition.•Metallic bonded P and organic P dominated TP removal in Fe-C added CW.
Insufficient dissolved oxygen (DO) for ammonia oxidation and limited electron donor for denitrification inhibit the nitrogen removal performance of constructed wetlands (CWs). To solve the problems, partially unsaturated CWs filled with biochar (C) and/or iron shavings (Fe) as functional substrate were proposed in this study and its mechanism on pollutant removal was thoroughly analyzed from the aspects of micro-environment property surrounding substrate, microbial function, plant toxicity, among others. Results showed that partially unsaturated section significantly improved the removal of NH4+-N from 25.1 ± 0.3 mg/L to <10 mg/L. The addition of Fe and Fe-C combination resulted in a better total nitrogen removal of 76.1 ± 0.6% and 86.5 ± 1.7% respectively compared with traditional CWs. For Fe-C combination, Fe, rather than C, was supposed to be the electron donor for nitrate (NO3–-N) removal. Moreover, the lower oxidation–reduction potential (ORP) in the micro-environment surrounding Fe-C combination than that surronding Fe proved that biochar accelerated the transfer process once Fe released electron, which guaranteed the nitrogen removal with less Fe dosage (only 60% v/v). Massive Fe2+ and Fe3+ were produced by Fe, and biochar provided large surface for the bacterial adhesion and co-precipitation of Fe cations and phosphate (P). The enhanced formation of Fe,Ca,Al-P and Porg after Fe-C addition led to a high total phosphorus (TP) removal of 98%. The import of biochar reduced the dosage of Fe and its toxicity to Iris wilsoni. Therefore, compared with Fe, Fe-C combination is a high-efficiency and environmental-friendly functional substrate in CWs.
Based on the early-year observations from Neil Gehrels Swift Observatory, Liang et al. performed a systematic analysis for the shallow decay component of gamma-ray bursts (GRBs) X-ray afterglow, in ...order to explore its physical origin. Here we revisit the analysis with an updated sample (with Swift/XRT GRBs between 2004 February and 2017 July). We find that with a larger sample, (1) the distributions of the characteristic properties of the shallow decay phase (e.g., tb, SX, ΓX,1, and X,1) still accord with normal or lognormal distribution; (2) ΓX,1 and Γγ still show no correlation, but the tentative correlations of durations, energy fluences, and isotropic energies between the gamma-ray and X-ray phases still exist; (3) for most GRBs, there is no significant spectral evolution between the shallow decay segment and its follow-up segment, and the latter is usually consistent with the external-shock models; (4) assuming that the central engine has a power-law luminosity release history as , we find that the value q is mainly distributed between −0.5 and 0.5, with an average value of 0.16 0.12; (5) the tentative correlation between and disappears, so that the global three-parameter correlation ( ) becomes less significant; (6) the anticorrelation between LX and and the three-parameter correlation ( ) indeed exist with a high confidence level. Overall, our results are generally consistent with Liang et al., confirming their suggestion that the shallow decay segment in most bursts is consistent with an external forward shock origin, probably due to a continuous energy injection from a long-lived central engine.
Compared with suspended microalgae cultivation, attached microalgae cultivation for wastewater treatment has advantages of low biomass recovery costs and high robustness. As a heterogeneous system, ...the variation of photosynthetic capacity along biofilm depth lacks quantitative conclusions. The distribution curve of oxygen concentration along the depth of attached microalgae biofilm (f(x)) was detected by dissolved oxygen (DO) microelectrode, and a quantified model was built based on mass conservation and Fick's law. It revealed that the net photosynthetic rate at a certain depth (x) in the biofilm showed a linear relationship with the second derivatives of the distribution curve of oxygen concentration (f″(x)). In addition, the declining trend of photosynthetic rate along attached microalgae biofilm was relatively slow compared with the suspended system. The photosynthetic rate at 150–200 μm depth of algae biofilm was only 3.60 %–17.86 % of that at the surface layer. Moreover, the light saturation points of the attached microalgae got lower along the depth of biofilm. Compared to 400 lx light intensity, the net photosynthetic rate of microalgae biofilm at the depths of 100–150 μm and 150–200 μm increased by 389 % and 956 % under 5000 lx, respectively, showing the high photosynthesis potential with increasing light.
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•Quantified photosynthetic rate changes along algae biofilm depth were first reported.•Light attenuation in microalgal biofilm was different from suspended cultivation.•Photosynthetic rate at 150–200 μm depth was 3.60 %–17.86 % as much as surface biofilm.•Deep layer algae could regain high photosynthesis under enhanced illuminance.•Deep layer microalgae had relatively low light saturation point.
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