Understanding the impact of soil components on the environmental existence of Nonylphenol:From the perspective of soil aggregates.

Nonylphenol (4-NP) has significant adverse effects on the male reproductive system. 4-NP is commonly used in agriculture as a plasticizer and pesticide emulsifier. In the current study, two soil samples with different textures were collected to evaluate the impact of soil components on the environmental existence of 4-NP among soil aggregates. It was found that the presence of soil POM resulted in 4-NP exhibiting a significantly polarized distribution in soil aggregates, instead of the expected increase in content with decreasing particle size. High levels of organic matter and metal oxides result in a high carrying capacity of small aggregates for 4-NP in both soil textures, while POM results in a higher carrying capacity of large aggregates for 4-NP in clay soil. Another important finding is that the existence of 4-NP in soil was regulated by the percentage of aggregates. The results of contribution shown that although small aggregates in sand presented stronger 4-NP carrying capacity, whereas 4-NP was mainly distributed in large aggregates in sand. For clay soil, 4-NP was predominantly located in small aggregates with the 4-NP contributions of small aggregates amounting to 63.17%, despite the highest carrying capacity of 4-NP was observed in large aggregates. These results provide a theoretical basis to investigate the transport and transformation of 4-NP in the soil environment.

Construction of algal-bacterial consortia using green microalgae Chlorella vulgaris and As(III)-oxidizing bacteria: As tolerance and metabolomic profiling.

Bioremediation became a promising technology to resolve arsenic (As) contamination in aquatic environment. Since monoculture such as microalgae or bacteria was sensitive to environmental disturbance and vulnerable to contamination, green microalgae Chlorella vulgaris and arsenite (As(III)) - oxidizing bacteria Pseudomonas sp. SMS11 were co-cultured to construct algal-bacterial consortia in the current study. The effects of algae-bacteria (A:B) ratio and exposure As(III) concentration on algal growth, As speciation and metabolomic profile were investigated. Algal growth arrested when treated with 100 mg/L As(III) without the co-cultured bacteria. By contrast, co-cultured with strain SMS11 significantly enhanced As tolerance in C. vulgaris especially with A:B ratio of 1:10. All the As(III) in culture media of the consortia were oxidized into As(V) on day 7. Methylation of As was observed on day 14. Over 1% and 0.5% of total As were converted into dimethylarsinic acid (DMA) after 21 days cultivation when the initial concentrations of As(III) were 1 and 10 mg/L, respectively. Metabolomic analysis was further performed to reveal the response of consortia metabolites to external As(III). The enriched metabolomic pathways were associated with carbohydrate, amino acid and energy metabolisms. Tricarboxylic acid cycle and glyoxylate and dicarboxylate metabolism were upregulated under As stress due to their biological functions on alleviating oxidative stress and protecting cells. Both carbohydrate and amino acid metabolisms provided precursors and potential substrates for energy production and cell protection under abiotic stress. Alterations of the pathways relevant to carbohydrate or amino acid metabolism were triggered by energy requirement.

Gene regulation and ionome homeostasis in rice plants in response to arsenite stress: potential connection between transcriptomics and ionomics.

Ionomics and transcriptomics were applied to demonstrate response of rice to arsenite [As(III)] stress in the current study. Rice plants were cultured in nutrient solutions treated with 0, 100 and 500 µg/L As(III) coded as CK, As1 and As5, respectively. The rice ionomes exhibited discriminatory response to environmental disturbances. Solid evidence of the effects of As(III) stress on binding, transport or metabolism of P, K, Ca, Zn and Cu was obtained in this work. Differentially expressed genes (DEGs) in the shoots were identified in three datasets: As1 vs CK, As5 vs CK and As5 vs As1. DEGs identified simultaneously in two or three datasets were selected for subsequent interaction and enrichment analyses. Upregulation of genes involved in protein kinase activity, phosphorus metabolic process and phosphorylation were detected in the rice treated with As(III), resulting in the maintenance of P homeostasis in the shoots. Zn and Ca binding genes were up-regulated since excess As inhibited the translocation of Zn and Ca from roots to shoots. Increased expression of responsive genes including HMA, WRKY, NAC and PUB genes conferred As tolerance in the rice plants to cope with external As(III) stress. The results suggested that As(III) stress could disturb the uptake and translocation of macro and essential elements by rice. Plants could regulate the expression of corresponding genes to maintain mineral nutrient homeostasis for essential metabolic processes.

Detoxification and removal of arsenite by Pseudomonas sp. SMS11: Oxidation, biosorption and bioaccumulation.

Arsenite [As(III)] oxidizing bacteria have been widely studied for their detoxification ability through transforming As(III) into arsenate [As(V)]. However, few was focused on removal capacity of arsenic (As). In the current study, As(III) oxidation accompanied with removal of total As was observed in Pseudomonas sp. SMS11. The biosorption (unbinding and surface binding) and bioaccumulation (intracellular uptake) of As by the cells were investigated. Biosorption isotherm was defined adequately by Langmuir and Freundlich models. Biosorption kinetics was recommended by pseudo second-order model. For comparison, the bacteria were inoculated in pure water or culture media amended with different concentrations of As(III) to evaluate the remediation capacity without or with bacterial growth. After removing unbound As, surface bound and intracellular As were sequentially separated using EDTA elution and acidic extraction from bacterial cells. Without bacterial growth, oxidation of As(III) was retarded and the maximum values of surface bound and intracellular As were 4.8 and 10.5 mg/g, respectively. Efficient oxidation and high adsorption capacity were observed after bacterial growth. The surface bound and intracellular As achieved up to 555.0 and 2421.5 mg/g, respectively. Strain SMS11 exhibited great accumulation capacity of As in aqueous solutions, indicating potential application in detoxification and removal of As(III) contamination. The results also suggested that bioremediation via bacteria should be based on living cells and bacterial growth rate.

Ionome profiling and arsenic speciation provide evidence of arsenite detoxification in rice by phosphate and arsenite-oxidizing bacteria.

Arsenite (As(III)) as the most toxic and mobile form is the dominant arsenic (As) species in flooded paddy fields, resulting in higher accumulation of As in paddy rice than other terrestrial crops. Mitigation of As toxicity to rice plant is an important way to safeguard food production and safety. In the current study, As(III)-oxidizing bacteria Pseudomonas sp. strain SMS11 was inoculated with rice plants to accelerate conversion of As(III) into lower toxic arsenate (As(V)). Meanwhile, additional phosphate was supplemented to restrict As(V) uptake by the rice plants. Growth of rice plant was significantly inhibited under As(III) stress. The inhibition was alleviated by the introduction of additional P and SMS11. Arsenic speciation showed that additional P restricted As accumulation in the rice roots via competing common uptake pathways, while inoculation with SMS11 limited As translocation from root to shoot. Ionomic profiling revealed specific characteristics of the rice tissue samples from different treatment groups. Compared to the roots, ionomes of the rice shoots were more sensitive to environmental perturbations. Both extraneous P and As(III)-oxidizing bacteria SMS11 could alleviate As(III) stress to the rice plants through promoting growth and regulating ionome homeostasis.

Promotion of growth and phytoextraction of cadmium and lead in Solanum nigrum L. mediated by plant-growth-promoting rhizobacteria.

Plant growth-promoting rhizobacteria (PGPR) are a specific category of microbes that improve plant growth and promote greater tolerance to metal stress through their interactions with plant roots. We evaluated the effects of phytoremediation combining the cadmium accumulator Solanum nigrum L. and two Cd- and Pb-resistant bacteria isolates. To understand the interaction between PGPR and their host plant, we conducted greenhouse experiments with inoculation treatments at Nanjing Agricultural University (Jiangsu Province, China), in June 2018. Two Cd- and Pb-resistant PGPR with various growth-promoting properties were isolated from heavy metal-contaminated soil. 16S rRNA analyses indicated that the two isolates were Bacillus genus, and they were named QX8 and QX13. Pot experiments demonstrated that inoculation may improve the rhizosphere soil environment and promote absorption of Fe and P by plants. Inoculation with QX8 and QX13 also enhanced the dry weight of shoots (1.36- and 1.7-fold, respectively) and roots (1.42- and 1.96-fold) of plants growing in Cd- and Pb-contaminated soil, and significantly increased total Cd (1.28-1.81 fold) and Pb (1.08-1.55 fold) content in aerial organs, compared to non-inoculated controls. We also detected increases of 23% and 22% in the acid phosphatase activity of rhizosphere soils inoculated with QX8 and QX13, respectively. However, we did not detect significant differences between inoculated and non-inoculated treatments in Cd and Pb concentrations in plants and available Cd and Pb content in rhizosphere soils. We demonstrated that PGPR-assisted phytoremediation is a promising technique for remediating heavy metal-contaminated soils, with the potential to enhance phytoremediation efficiency and improve soil quality.

Enhanced phosphate removal from wastewater by using in situ generated fresh trivalent Fe composition through the interaction of Fe(II) on CaCO3.

Excessive existences of nutrients such as phosphate in the aqueous environment remain as a heavy concern although many researches have been reported for dealing with their removal. Based on the understanding toward the interactions of Fe compounds with phosphate and carbonate from many available researches, we designed a very simple and efficient approach for phosphate removal by using in situ generated fresh trivalent Fe composition through the interaction of Fe(II) as FeSO4 on CaCO3. Addition and agitation of Fe(II) and CaCO3 simultaneously to phosphate solution allowed an amorphous Fe(III)-P or Ca-Fe(III)-P precipitation, with a phosphate removal rate close to 100%, to reduce the residual phosphorus concentration less than 0.03 mg/L from 100 mg/L, reaching the discharge limit, even with the addition amounts of CaCO3 as low as a stoichiometric ratio of CaCO3/PO43- at 0.9 and ratio of Fe(II)/PO43- at 1.5, and the percent of P2O5 in the precipitate was as high as 19.4% enough as phosphate source for fertilizer production. Different from the alkaline process with enough OH- group, the slow hydrolysis of CaCO3 resulting in low concentration of OH- group for the formation of Fe(OH)2, which was oxidized soon by air into trivalent Fe, achieved a continuous generation of fresh ferric composition for phosphate precipitation and could avoid its rapid formation and subsequent transformation into stable FeOOH of large particle size to lose the activity. These results based on the synergistic effect of using CaCO3 and Fe(II) together may have applications in the treatment of eutrophic wastewater through a process with many advantages of easy operation and low-cost besides the high removal efficiency with phosphate percentage inside the precipitate high enough to serve for fertilizer production.

Grinding siderite with ferric sulfate to generate an active ferrous source for Cr(VI) reduction.

Activated siderite, endowed with excellent properties, was simply prepared by co-grinding with Fe sulfate to enhance its high reducing ability for Cr(VI). Batch experiments were conducted to investigate the main affecting parameters, such as material ratio, pH, temperature, etc. The removal of Cr(VI) by activated siderite was completed within 4 h of the reaction. The activated siderite maintained a high removal effect of Cr(VI) within a wide pH range (3-9). Various analytical methods, including XRD, SEM/EDS, XPS, etc., were employed to characterize the samples and discover variations before and after the reaction. The Fe (Ⅱ) in activated siderite becomes highly active, and it can even be released from the solid phase in the mildly acidic liquid phase to efficiently reduce Cr(VI) and mitigate its toxicity. These findings introduce an innovative approach for activating various minerals widely distributed in nature to promote the recovery of the ecological system.

Clinicopathological Analysis of Densely and Sparsely Granulated Somatotroph Tumors of Pituitary.

OBJECTIVE: Somatotroph tumors are the second most common type of pituitary neuroendocrine tumors, which can be further classified into 2 subtypes-densely granulated somatotroph tumors (DGSTs) and sparsely granulated somatotroph tumors (SGSTs). The aim of this study was to investigate the clinical significance of the 2 subtypes in a retrospective analysis. METHODS: From the database of the Ningbo Clinical Pathology Diagnosis Center, we collected patients diagnosed with pituitary somatotroph tumors. We then compiled pertinent clinical and radiological data and proceeded with histopathological examination involving hematoxylin-eosin staining and immunohistochemical staining. Subsequent analysis compared the 2 subtypes using either χ2 test or Fisher exact test. RESULTS: We analyzed 40 cases of somatotroph tumors, 18 cases DGSTs and 22 SGSTs. Male-to-female ratio was 5:4 for DGSTs and 4:7 for SGSTs. Mean age was 52.83 years for DGSTs and 47.18 years for SGSTs. Statistically significant differences were observed between the DGST and SGST groups in invasiveness (P = 0.0267) and postoperative remission (P = 0.007). Cells of both DGSTs and SGSTs exhibited coexpression of PIT1, growth hormone, and CAM5.2, although the patterns of CAM5.2 expression differed between the 2 subtypes. CONCLUSIONS: The efficacy of CAM5.2 staining in distinguishing between DGSTs and SGSTs was demonstrated. SGSTs, with their increased invasiveness and lower remission rate, are a high-risk subtype. The histological subtype of somatotroph tumors plays a crucial role in guiding treatment decisions and prognostic evaluation in affected patients.

Mechanochemical remediation of the chlorinated compounds contaminated soil depending on the minerals inside-the most reasonable approach.

This study explored a possible destruction of hexachlorobenzene (HCB) as example of persistent organic pollutants (POPs) as well as the dechlorination mechanism by directly using minerals in the soil, such as antigorite, talc and olivine. Compared with a stable quartz phase of SiO2, all three Mg silicate minerals demonstrated certain degrading capacity for HCB with different efficiency order as: antigorite > talc > olivine > SiO2 at 2 h of milling time. Interestingly, olivine exhibited a better performance than antigorite at 4 h of milling time, giving destruction percentage of 92.7% over 89.0% even at high concentrated HCB up to 5% added. Raman and ESR characterizations of the ball milled sample with olivine indicated the formation of amorphous carbon and graphitic carbon, and the occurrence of free radicals was observed to play an important role in dechlorination and carbonization of HCB. The first identified effectiveness of directly using Mg silicate minerals, allowed no addition of active chemicals during the ball milling, therefore avoided the concern over extrinsic contaminations on the soil. Olivine was further utilized to deal with actual contaminated soil and showed unique advantages on application prospects.

Mechanochemical remediation of fluoranthene contaminated soil and biotoxicity evaluation.

A mechanochemical (MC) method was employed for the remediation of soil contaminated with fluoranthene (C16H10, FL) a four-ringed polycyclic aromatic hydrocarbon (PAH) containing three benzene rings and a central five-membered heterocyclic ring, with the effects of soil inorganic components, milling conditions, and the degradation mechanism investigated. Results showed that the addition of SiO2 and kaolin to soil resulted in a greater increase in the effectiveness of FL removal than other inorganic additives. After 3 hours of milling at 500 rpm, the FL removal rate from SiO2 containing soil, reached 99.26%, with the removal efficiency increasing in accordance with an increase in milling duration and speed. The milled samples were characterized by FT-IR, Raman spectroscopy, and GC-MS analysis, revealing the mechanism of FL degradation, including destruction of the aromatic skeleton structure and the formation of amorphous carbon and graphite. The MC remediation method was applied to FL contaminated soil, showing that FL was efficiently degraded in soil without any soil additives, resulting in a significant reduction in the biotoxicity of the remediated soil. The organic matter, moisture content and pH of the actual soil changed slightly after mechanical ball milling. Thus, the MC method has high potential in the remediation of PAH-contaminated soils.HIGHLIGHTSA mechanochemical (MC) method for the degradation of fluoranthene was assessed.The use of silica and kaolin as soil additives enhances fluoranthene remediation.Fluoranthene can be efficiently removed from contaminated soil by milling alone.The degradation mechanism was skeleton structure destruction and carbonization.The biotoxicity of soil was significantly reduced by milling.

Increased GABAergic projections in the paraventricular nucleus regulate colonic hypersensitivity via oxytocin in a rat model of irritable bowel syndrome.

Irritable bowel syndrome (IBS) is characterized by gastrointestinal dysmotility and visceral hyperalgesia, and the impaired brain-gut axis is accepted as a crucial cause for the onset of IBS. The objective of this study is to investigate the effects of the adaptive changes in the central neural system induced by stress on IBS-like syndromes in rats. Long-term water avoidance stress (WAS) was used to prepare IBS animals. The changes in neuronal excitation and GABA expression were shown by immunohistochemistry. The mRNA and protein expressions of neurotransmitters were detected with Quantitative reverse-transcription PCR (qRT-PCR) and Enzyme-linked immunosorbent assay (ELISA). The intestinal transit time, fecal moisture content, and abdominal withdrawal reflex scores of rats were recorded to monitor intestinal motility and visceral hyperalgesia. In the WAS-treated rats with enhanced intestinal motility and visceral hypersensitivity, more GABAergic projections were found in the paraventricular nucleus (PVN) of the hypothalamus, which inhibited the firing rate of neurons and decreased the expression of oxytocin. Exogenous oxytocin improved gut motility and decreased AWR scores. The inhibition of oxytocin by the adaptive GABAergic projection in the PVN might be an important mediator of IBS, which indicates a potential novel therapeutic target.

Regulation of the central amygdala on intestinal motility and behavior via the lateral hypothalamus in irritable bowel syndrome model mice.

BACKGROUND: Impaired bidirectional communication between the gastrointestinal tract and the central nervous system (CNS) is closely related to the development of irritable bowel syndrome (IBS). Studies in patients with IBS have also shown significant activation of the hypothalamus and amygdala. However, how neural circuits of the CNS participate in and process the emotional and intestinal disorders of IBS remains unclear. METHODS: The GABAergic neural pathway projecting from the central amygdala (CeA) to the lateral hypothalamus (LHA) in mice was investigated by retrograde tracking combined with fluorescence immunohistochemistry. Anxiety, depression-like behavior, and intestinal motility were observed in the water-immersion restraint stress group and the control group. Furthermore, the effects of the chemogenetic activation of the GABAergic neural pathway of CeA-LHA on behavior and intestinal motility, as well as the co-expression of orexin-A and c-Fos in the LHA, were explored. KEY RESULTS: In our study, Fluoro-Gold retrograde tracking combined with fluorescence immunohistochemistry showed that GABAergic neurons in the CeA were projected to the LHA. The microinjection of the gamma-aminobutyric acid (GABA) receptor antagonist into the LHA relieved anxiety, depression-like behavior, and intestinal motility disorder in the IBS mice. The chemogenetic activation of GABAergic neurons in the CeA-LHA pathway led to anxiety, depression-like behavior, and intestinal motility disorder. In addition, GABAergic neurons in the CeA-LHA pathway inhibited the expression of orexin-A in the LHA, and orexin-A was co-expressed with GABAA receptors. CONCLUSIONS & INFERENCES: The CeA-LHA GABAergic pathway might participate in the occurrence and development of IBS by regulating orexin-A neurons.

Characterization of physicochemical parameters and bioavailable heavy metals and their interactions with microbial community in arsenic-contaminated soils and sediments.

Mobility and toxicity of heavy metal contamination in the environment are highly dependent on its bioavailability. Most of previous studies focused on total heavy metal contents and their influence on microbial community in soils and sediments. Little were concerned about bioavailable fractions. In the current study, soil and sediment samples were collected near an abandoned realgar mine in Shimen County, China. Bioavailable heavy metals including Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Sb, and Pb in the samples were extracted using three-step sequential extraction method. Interactions among physicochemical parameters, total and bioavailable heavy metals, and microbial community in the collected samples were investigated. The study area has been severely contaminated by As with a concentration up to 2158 mg·kg-1 detected. The result of principal component analysis showed that the abundance of operational taxonomic units (OTUs) in the soils were obviously different from those in the sediments. In the soil samples, pH made a dominant contribution on the OTU abundance of microbial community. Correlation analyses revealed that the alpha diversity indices and microbial taxon were most correlated with bioavailable fractions of heavy metals in all the samples. That means bioavailable heavy metals rather than total heavy metals or physicochemical parameters played a more important role on richness and diversity of microbial community. Little connections were observed between microbial community and As no matter total concentration or bioavailable fraction. However, bioavailable Fe and Mn were recognized as the major driving force shaping the taxonomic structure of microbial community due to their relatively high concentrations and high affinity to other heavy metal contamination in soils and sediments.

Interactions among heavy metal bioaccessibility, soil properties and microbial community in phyto-remediated soils nearby an abandoned realgar mine.

Soil samples were collected from a representative arsenic (As) contaminated region under phytoremediation of hyperaccumulation plants. Relative abundance and diversity of microbial communities in the soil samples were characterized via 16S rRNA genes sequencing. At the phylum level, Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes, Gemmatimonadetes and Firmicutes shows the highest abundance, accounting for more than 90 % of the classified sequences in the soil samples. Physicochemical parameters including pH, total organic carbon (TOC), cation exchange capacity (CEC), and electrical conductivity (EC), and heavy metal concentrations including total and bioaccessible contents in the soil samples were determined to investigate potential relationships between the microbial communities and the environmental factors. Principal component analysis (PCA) based on the operational taxonomic units (OTUs) matrix revealed distinct separation among the samples. The soil pH was confirmed as the dominant force to discriminate the soil samples with similar land use type and heavy metal contamination. There was little relevance between the total concentrations of heavy metals and the microbial communities. However, the bioaccessible concentrations of heavy metals were associated with the physicochemical parameters and relative abundances of bacterial genera according to correlation analyses. Although the soil samples were considerably contaminated by As, the abundances of bacterial phyla linked with As were lower than 1.0 % in most of the soil samples. The results indicated that the abundances of microbial communities in the soils were the consequence of concerted effects from all the environmental factors.

Promoted removal of phosphate by layered double hydroxides combined with bacteria: Application of novel carriers in biofilm reactor.

Layered double hydroxides (LDHs) were used as carriers for the microbial consortium in sequencing biofilm batch reactor (SBBR) without inoculation to promote the removal of phosphate. The adsorption capacity of [Zn-Al]-LDH was significantly better than that of [Mg-Al]-LDH. The pollutants removal performance and behavior of microorganisms in LDH-SBBRs were also investigated. LDH-SBBRs showed improved removal efficiencies of COD, phosphate and TP with a low C/N ratio. Microscopic images show that biofilm formed rapidly in LDH-SBBRs. SEM-EDS detected abundant carbon and phosphorus, implying that biomass and phosphorus accumulate on LDH carriers. The microbial compositions of the three SBBRs indicate that the LDHs carriers improved the biodiversity of biofilm in the bioreactors. Synergistic effects of adsorption and biodegradation between well-structured LDHs and microorganisms led to an improved phosphate removal performance of LDH-SBBR. The results also demonstrate that [Zn-Al]-LDH carrier is the best for improving SBBR phosphate removal.

Investigation on the effect of different additives on anaerobic co-digestion of corn straw and sewage sludge: Comparison of biochar, Fe3O4, and magnetic biochar.

The co-digestion of corn straw and sewage sludge with different additives (biochar, magnetic biochar, Fe3O4) were investigated. The highest cumulative methane yield of 245.15 mL/g VSadded was obtained with the Fe3O4 addition ratio of 5 g/kg, which was 60.47% higher than that of the control run (without additives). The lag phase time was shortened from 5.46 to 3.82 days with a biochar dosage of 5 g/kg. The performance of Fe3O4 on methane production from the co-digestion process was better than that of the biochar and magnetic biochar. The direct interspecies electron transfer (DIET) was enhanced with regard to the increased concentration of acetic acid and decreased concentration of propionic acid. Microbial community analysis showed that the Geobacter and Methanosarcina were selectively enriched on the surface of Fe3O4, promoting the DIET and acetoclastic methanogenesis pathway. The cost-benefit analysis proved that the strategy of recycling Fe3O4 additive has the best economic benefit.

Associations of Household Solid Fuel Use With Falls and Fall-Related Injuries in Middle-Aged and Older Population in China: A Cohort Study.

Objective: This study evaluated the associations of solid fuels with incidence of falls and fall-related injuries. Methods: Data were taken from wave 1∼4 of the China Health and Retirement Longitudinal Study, including 15,651 participants aged 45 years and older. Modified Poisson regression was used to examine the associations of solid fuels with falls and fall-related injuries. Results: Modified Poisson regression analysis showed that solid fuels users for cooking had an increasing incidence of falls and fall-related injuries, with RR of 1.211 (95% CI: 1.124, 1.305) and 1.248 (95% CI: 1.107, 1.408); for heating had an incidence, with RR of 1.178 (95% CI: 1.062, 1.306) and 1.134 (95% CI: 0.963, 1.335); combined for cooking and heating, with RR of 1.247 (95% CI: 1.105, 1.408) and 1.185 (95% CI: 0.982, 1.431). Conclusion: Our study suggests that solid fuel use is associated with a higher incidence of falls and fall-related injuries among adults aged 45 years and older in China. It is necessary to restrict solid fuel use to reduce household air pollution and make stronger environmental protection policies to improve household environment.

Activation of Calcium-Sensing Receptor in the Area Postrema Inhibits Food Intake via Glutamatergic and GABAergic Signaling Pathways.

SCOPE: A high-protein diet has become a popular way to lose weight. Calcium-sensing receptor (CaSR) is activated by amino acids in addition to calcium ions. CaSR shows dense expression in the area postrema (AP), which participates in feeding regulation. The effect of CaSR in the AP on food intake and the potential mechanism involved is investigated. METHODS AND RESULTS: Male C57BL/6 mice are used to observe the effect of R568 (agonist of CaSR) on food intake. Enzyme-linked immunosorbent assay, immunofluorescence staining, and chemogenetics are used to explore the neural signaling involved. CaSR activation in the AP inhibited acute feeding; R568 increases the content of glutamate and γ-aminobutyric acid (GABA) in the AP, whereas only glutamatergic neurons mediate the effect of R568. GABA-A receptor and ionic glutamate receptor (N-methyl-D-aspartate receptor [NMDAR]) in the paraventricular nucleus of hypothalamus (PVN) are involved in the effect of R568. Promotion of oxytocin (OT) synthesis in the PVN also participates in the effect of R568, and this mechanism is mediated by NMDAR in the PVN. CONCLUSION: CaSR activation in the AP suppresses feeding, and AP-PVN glutamatergic and GABAergic signaling pathways are involved.

Activity enhancement and the anammox mechanism under low temperature via PVA-SA and nano Fe2O3-PVA-SA entrapped beads.

Anaerobic ammonia-oxidizing bacteria (AAOB) have a long growth time and low activity at low temperatures. In suspended systems, sludge is easily lost, which limits the mainstream application of anaerobic ammonia oxidation (anammox).Entrapment provides effective ideas for solving these problems. In this study, polyvinyl­sodium alginate (PVA-SA) and nano Fe2O3-PVA-SA entrapment beads were prepared to discuss the effectiveness of entrapment enhanced anammox sludge at low temperatures. The differences in the entrapped beads and granules were compared to analyze the strengthening mechanism. The results show that the nitrogen removal performance of granules, PVA-SA and nano Fe2O3-PVA-SA entrapped beads, first decreased and then increased during the cooling and low-temperature operation. Nano Fe2O3-PVA-SA entrapped beads showed the smallest decline and the highest degree of recovery. Reaction metering ratio (△NO2--N/△NH4+-N and △NO3--N/△NH4+-N) showed that entrapment could realize Nitrite oxidizing bacteria (NOB) inhibition and improve the activity of denitrifying bacteria (DNB) to promote the removal of total nitrogen by providing a strict anaerobic environment. The results demonstrate that entrapment is beneficial for maintaining the content of heme c, specifically, nano Fe2O3 can stimulate its production, and is beneficial for alleviating the reduction of hydrazine dehydrogenase (HDH) enzyme activity. The extracellular polymeric substances (EPS) content and analysis showed that entrapment does not change the composition of EPS, and can maintain the EPS content. Nano Fe2O3 can stimulate AAOB to secrete more EPS to maintain sludge stability. From a molecular perspective, entrapment can maintain the expression of functional genes, promote the enrichment of AAOB, thus improving the nitrogen removal performance from the dual perspectives of "quality" and "quantity".