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Background: Irritable bowel syndrome (IBS) is a functional gut disease characterized by visceral hypersensitivity and gut motor dysfunction. Serotonin (5-hydroxytryptamine, 5-HT) is an important enteric neurotransmitter. High levels of 5-HT aggravate IBS symptoms. The serotonin reuptake transporter (SERT) is a membrane-embedded transporter involved in IBS pathogenesis that plays an important role in regulating 5-HT signaling. Aim: We investigated whether gut motor function was altered in SERT-knockout (SERT-KO) rats. Additionally, we sought to determine whether Shugan decoction (SGD), a clinically experienced prescription for the treatment of IBS, exerts regulatory effects on intestinal motility in SERT-KO rats, and attempted to identify the mechanisms involved. Method: SERT-KO rats were produced by transcription activator-like effector nuclease (TALEN) technology. Fecal pellet output was measured for ten consecutive days to estimate distal colonic motility. Small intestinal motility was measured by charcoal-meal experiments. The colonic and small intestinal muscle contractile activities were measured by organ bath study. Western blot was used to analyze the muscarinic receptor expression in colon tissue. Result: Compared with that in wild-type (WT) rats, the defecation amount, amplitude of spontaneous contraction, and the tension of ACh-induced contraction of colonic longitudinal smooth muscle in SERT-KO rats were significantly increased. The expression of muscarinic receptor subtype-3 (M3R) in the colons of SERT-KO rats was also elevated. SGD can decrease defecation of SERT-KO rats. Moreover, SGD reduced the amplitude of spontaneous contraction, the frequency and tension of ACh-induced contraction of colonic longitudinal smooth muscle, and the expression of M3R in the colon in SERT-KO rats. Conclusions: SERT-KO rats showed increased defecation accompanied by enhanced colonic motility and M3R expression. The findings suggest that SGD modifies colonic dysmotility and reduces defecation in SERT-KO rats by down-regulating M3R expression in the colon. [ABSTRACT FROM AUTHOR]

Abstract The heavy metals (Cu, Cr, Zn, Cd, Pb) were analysed for 217 surface sediment samples collected across 14 typical intertidal zone areas in China. The data reveals the heavy metals spatial distribution patterns and correlations among their concentrations. Cu, Zn, Cd and Cr showed similar trends of spatial variation and the correlations between the concentrations of every two heavy metals were significantly positive except for the correlation between Pb and Cr concentrations. By using Nemerow index method, Enrichment factor and Sediment Quality Guidelines, it is found that Hangzhou Bay and Jiulong River Estuary were polluted, Yingluo Bay and Dongzhaigang Bay were Cd-rich areas. Except Beidaihe shoal, Sishili Bay and Yingluo Bay that were not exposed to any ecological risk of heavy metals and had no adverse biotoxic effects, the other 11 typical intertidal zone areas were exposed to moderate ecological risk of heavy metals in the sediment with potential adverse biotoxic effects. Highlights • The ecological risk of 14 typical areas across China heavy metals was assessed by using multiple methods. • The survey sites were classified into five bays and six typical estuaries to compare differences heavy metal concentrations. • Heavy metals Cu, Zn, Cd and Cr in intertidal zone environments of 14 typical areas showed similar trends of spatial variation. • High-value heavy metals were located in East China Sea and the second highest value appeared in Bohai intertidal zone area. [ABSTRACT FROM AUTHOR]

The evaluation on island ecological vulnerability (IEV) can help reveal the comprehensive characteristics of the island ecosystem and provide reference for controlling human activities on islands. An IEV evaluation model which reflects the land–sea dual features, natural and anthropogenic attributes, and spatial heterogeneity of the island ecosystem was established, and the southern islands of Miaodao Archipelago in North China were taken as the study area. The IEV, its spatial heterogeneity, and its sensitivities to the evaluation elements were analyzed. Results indicated that the IEV was in status of mild vulnerability in the archipelago scale, and population pressure, ecosystem productivity, environmental quality, landscape pattern, and economic development were the sensitive elements. The IEV showed significant spatial heterogeneities both in land and surrounding waters sub-ecosystems. Construction scale control, optimization of development allocation, improvement of exploitation methods, and reasonable ecological construction are important measures to control the IEV. [ABSTRACT FROM AUTHOR]

Highlights • An evaluation model of estuarine landscape ecological sensitivity was established. • The model was formed based on landscape pattern across temporal and spatial scales. • Two indices were proposed to reflect spatiotemporal variations of landscape ecosystem. • The application in Chongming Island verified the model's effectiveness and applicability. • The 200 m scale balanced all the demands and was the optimal scale to apply the model. Abstract Evaluating landscape ecological sensitivity in estuarine areas is important for providing reference for landscape optimization and ecological conservation, however, the comprehensive characteristics of the landscape ecological sensitivity, including the changes under various disturbances, the spatiotemporal heterogeneities, and the multiple scale effects, have received insufficient attention. A model to evaluate estuarine landscape ecological sensitivity was established based on landscape pattern across temporal and spatial scales. Two new indices, namely, landscape ecological condition index (LECI) and landscape ecological sensitivity index (LESI), were proposed using remote sensing and geographic information system methods. Chongming Island, a typical and important estuarine area in China, was selected as the study area to demonstrate the model. Evaluation factors were integrated following the landscape pattern; different years and periods in the last 30 years were used to reflect the temporal scales; and spatial scales of 100 m, 200 m, 400 m, and 800 m, which refer to the evaluation unit size, were adopted to validate the spatial scale effect and seek the optimal scale to apply the model. Results indicated that the LECI initially slightly decreased and then increased from 1988 to 2017, and the LESI continuously increased along the periods. The two indices exhibited distinct spatiotemporal heterogeneities, which were driven by different development goals and strategies of the island in different periods. Along the scales from 100 m to 800 m, the LECI and LESI in the entire study area gradually decreased; they tended to be homogenizing, and the details were lost in the spatial distributions. The 200 m scale balanced all the demands of accuracy, spatial heterogeneity, and appropriate data volume, and was the optimal spatial scale to apply the model. The application of the model in Chongming Island verified its effectiveness to represent the comprehensive characteristics of the estuarine landscape ecological sensitivity, and the model can be widely used in different estuarine areas because of its high applicability. [ABSTRACT FROM AUTHOR]

Competing Interests: None declared.

Background: The effect of Shugan Decoction (SGD) on intestinal motility and visceral hypersensitivity in Water avoid stress (WAS)-induced diarrhea predominant irritable bowel syndrome (IBS-D) model rats has been confirmed. However, the mechanisms of its action involved in the treatment of IBS-D need to be further studied. Intestinal microbiota plays an important role in maintaining intestinal homeostasis and normal physiological function. Changes in the intestinal microbiota and its metabolites are thought to participate in the pathophysiological process of IBS., Aim: This study aimed to analyze the influence of SGD on intestinal microbiota and fecal metabolites in IBS-D rats by multiple omics techniques, including metagenomic sequencing and metabolomics., Methods: We measured the intestinal motility and visceral sensitivity of three groups of rats by fecal pellets output and colorectal distension (CRD) experiment. In addition, metagenome sequencing analysis was performed to explore the changes in the number and types of intestinal microbiota in IBS-D model rats after SGD treatment. Finally, we also used untargeted metabolomic sequencing to screen the metabolites and metabolic pathways closely related to the therapeutic effect of SGD., Results: We found that compared with the rats in the control group, the fecal pellets output of the rats in the WAS group increased and the visceral sensitivity threshold was decreased ( P < 0.05). Compared with the rats in the WAS group, the fecal pellets output of the SGD group was significantly decreased, and the visceral sensitivity threshold increased ( P < 0.05). Besides, compared with the rats in the WAS group, the relative abundance of Bacteroidetes increased in SGD group, while that of Firmicutes decreased at the phylum level, and at the species level, the relative abundance of Bacteroides sp. CAG:714 , Lactobacillus reuteri and Bacteroides Barnesiae in SGD group increased, but that of bacterium D42-87 decreased. In addition, compared with the WAS group, several metabolic pathways were significantly changed in SGD group, including Taurine and hypotaurine metabolism, Purine metabolism, Sulfur metabolism, ABC transporters, Arginine and proline metabolism and Bile secretion., Conclusion: SGD can regulate specific intestinal microbiota and some metabolic pathways, which may explain its effect of alleviating visceral hypersensitivity and abnormal intestinal motility in WAS-induced IBS-D rats., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Hang, Wang, Feng, Zhou, Meng, Jiang and Yuan.)

Background: It has been reported that 5-hydroxytryptamine (5-HT, serotonin) metabolism is involved in the pathogenesis of irritable bowel syndrome (IBS) and that either Shugan decoction (SGD) or fecal microbiota transplantation (FMT) can alleviate the symptoms of IBS in patients and animal models. But the synergistic effect of FMT and SGD on 5-HT metabolism and IBS symptoms has not been investigated., Aim: The main purpose of this study is to observe the synergistic effect of FMT with SGD on symptoms and 5-HT metabolism in IBS-D rats induced by water avoidance stress (WAS). Moreover, the possible material basis of the FMT was investigated., Methods: In experiment I, rats were randomly divided into seven groups. Control group: routine feeding; WAS→ Control group: routine feeding with fecal microbiota liquid (FML) 1 (derived from rats in WAS group) gavage since the fourth day; WAS group: 10 days WAS with routine feeding; SGD group: 10 days WAS with SGD gavage since the fourth day on the base of routine feeding; Control→ WAS group: 10 days WAS with FML2 (derived from rats in Control group) gavage since the fourth day with routine feeding; SGD→ WAS group: 10 days WAS with FML3 (derived from rats in SGD group) gavage since the fourth day with routine feeding; SGD + (Control→ WAS) group: 10 days WAS with SGD and FML2 (derived from rats in Control group) gavage since the fourth day with routine feeding. In experiment II, rats were randomly divided into three groups. Control group: routine feeding; Control→ WAS group: 10 days WAS with FML2 gavage since the fourth day with routine feeding; FControl→ WAS group: 10 days WAS with FML2 filtrate gavage since the fourth day. The number of fecal pellets output (FPT) and the pain pressure threshold (PPT) were recorded. The histological changes in colon mucosa were observed by hematoxylin-eosin (HE) stain. The number of enterochromaffin cells (ECs), the content of 5-HT, and the expression of serotonin reuptake transporter (SERT) protein in the colon were measured by immunofluorescence or western blotting., Results: Compared with that in the control group, the PPT and the expression of SERT in the WAS group and that in the WAS→ Control group were decreased with the increased number of ECs and the level of 5-HT in colon. But the FPT was not increased in the WAS→ Control group although that was increased in the WAS group. Compared with that in the WAS group, the FPT, the PPT, the number of ECs, the level of 5-HT, and the expression of SERT protein in colon in the SGD group, control→ WAS group, SGD→ WAS group, and SGD+(Control→ WAS) group were all recovered. The recovery of these indicators in the Control→ WAS group and that in the FControl→ WAS group was not significantly different., Conclusion: No synergistic effect of SGD with FMT on IBS symptoms induced by WAS was found. The metabolites of intestinal microbiota may be the main active substances of the FML derived from normal rats to alleviate WAS-induced IBS symptoms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Meng, Feng, Hang, Zhou, Wang and Yuan.)

Background: Irritable bowel syndrome (IBS) is a functional gut disease characterized by visceral hypersensitivity and gut motor dysfunction. Serotonin (5-hydroxytryptamine, 5-HT) is an important enteric neurotransmitter. High levels of 5-HT aggravate IBS symptoms. The serotonin reuptake transporter (SERT) is a membrane-embedded transporter involved in IBS pathogenesis that plays an important role in regulating 5-HT signaling., Aim: We investigated whether gut motor function was altered in SERT-knockout (SERT-KO) rats. Additionally, we sought to determine whether Shugan decoction (SGD), a clinically experienced prescription for the treatment of IBS, exerts regulatory effects on intestinal motility in SERT-KO rats, and attempted to identify the mechanisms involved., Method: SERT-KO rats were produced by transcription activator-like effector nuclease (TALEN) technology. Fecal pellet output was measured for ten consecutive days to estimate distal colonic motility. Small intestinal motility was measured by charcoal-meal experiments. The colonic and small intestinal muscle contractile activities were measured by organ bath study. Western blot was used to analyze the muscarinic receptor expression in colon tissue., Result: Compared with that in wild-type (WT) rats, the defecation amount, amplitude of spontaneous contraction, and the tension of ACh-induced contraction of colonic longitudinal smooth muscle in SERT-KO rats were significantly increased. The expression of muscarinic receptor subtype-3 (M 3 R) in the colons of SERT-KO rats was also elevated. SGD can decrease defecation of SERT-KO rats. Moreover, SGD reduced the amplitude of spontaneous contraction, the frequency and tension of ACh-induced contraction of colonic longitudinal smooth muscle, and the expression of M 3 R in the colon in SERT-KO rats., Conclusions: SERT-KO rats showed increased defecation accompanied by enhanced colonic motility and M 3 R expression. The findings suggest that SGD modifies colonic dysmotility and reduces defecation in SERT-KO rats by down-regulating M 3 R expression in the colon., (Copyright © 2020 Wang, Dong, Wang, Meng, Bi, Sun, Zhang, Fan and Yuan.)