Red ginseng ameliorates lipotoxicity-induced renal fibrosis in hyperuricemia mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Chronic kidney disease can be caused by numerous diseases including obesity and hyperuricemia (HUA). Obesity may exacerbate the renal injury caused by HUA. Red ginseng, a steamed products of Panax ginseng Meyer root, is known for its remarkable efficacy in improving metabolic syndrome, such as maintaining lipid metabolic balance. However, the role of red ginseng on hyperuricemia-induced renal injury in obese cases remains unclear. AIM OF THE STUDY: This study aimed to investigate the action of red ginseng extract (RGE) on lipotoxicity-induced renal injury in HUA mice. MATERIALS AND METHODS: A high-fat diet (HFD)-induced obesity model was employed to initially investigate the effects of RGE on body weight, TC, OGTT, renal lipid droplets, and renal function indices such as uric acid, creatinine, and urea nitrogen. Renal structural improvement was demonstrated by H&E staining. Subsequently, an animal model combining obesity and HUA was established to further study the impact of RGE on OAT1 and ACC1 expression levels. The mechanisms underlying renal injury regulation by RGE were postulated on the basis of RNA sequencing, which was verified by immunohistochemical (including F4/80, Ki67, TGF-ß1, α-SMA, and E-cadherin), Masson, and Sirius red staining. RESULTS: RGE modulated HFD-induced weight gain, glucose metabolism, and abnormalities of uric acid, urea nitrogen, and creatinine. RGE alleviated the more severe renal histopathological changes induced by obesity combined with HUA, with down-regulated the protein levels of ACC1, F4/80, Ki67, TGF-ß1, and α-SMA, and up-regulated OAT1 and E-cadherin. CONCLUSIONS: RGE has ameliorative effects on chronic kidney disease caused by obesity combined with HUA by maintaining lipid balance and reducing renal inflammation and fibrosis.

N6-methyladenosine modification of the mRNA for a key gene in purine nucleotide metabolism regulates virus proliferation in an insect vector.

The titer of viruses that persist and propagate in their insect vector must be high enough for transmission yet not harm the insect, but the mechanism of this dynamic balance is unclear. Here, expression of inosine monophosphate dehydrogenase (LsIMPDH), a rate-limiting enzyme for guanosine triphosphate (GTP) synthesis, is shown to be downregulated by increased levels of N6-methyladenosine (m6A) on LsIMPDH mRNA in rice stripe virus (RSV)-infected small brown planthoppers (SBPHs; Laodelphax striatellus), the RSV vector, which decreases GTP content, thus limiting viral proliferation. Moreover, planthopper methyltransferase-like protein 3 (LsMETTL3) and m6A reader protein LsYTHDF3 are found to catalyze and recognize the m6A on LsIMPDH mRNA, respectively, and cooperate in destabilizing LsIMPDH transcripts. Co-silencing assays show that negative regulation of viral proliferation by both LsMETTL3 and LsYTHDF3 is partially dependent on LsIMPDH. This distinct mechanism limits virus replication in an insect vector, providing a potential gene target to block viral transmission.

Industrial agglomeration, FDI, and carbon emissions: new evidence from China's service industry.

In the context of economic servitization and low carbonization, the problem of carbon emissions in the service industry is worthy of attention. An essential channel for restraining carbon emissions from the service industry is industrial agglomeration. Based on provincial panel data from 2004 to 2021 in China, this study empirically analyzes the influence of the service industry's agglomeration on its CO2 emissions. The findings indicate that agglomeration significantly reduces the industry's carbon emissions. Next, producer services agglomeration has a significant carbon-reduction effect, whereas non-producer services agglomeration does not. Moreover, service industry agglomeration helps to restrain carbon emissions from the service industry in East China. However, it does not significantly affect carbon emissions in Central or West China. Regarding the moderating effect, foreign direct investment can enhance service industry agglomeration's carbon-reduction effect. Based on the results, relevant policy implications are provided.

Unraveling the interplay between antibiotic resistance genes and microbial communities in water and sediments of the intensive tidal flat aquaculture.

Tidal flats are formed valuably resources by the interaction of terrestrial and marine processes. Aquaculture on tidal flats has brought significant economic profits, but the over usage of antibiotics has resulted in the prevalence antibiotic resistance genes (ARGs) which pose serious threats to ecosystems. However, ARG abundances and bacterial community assemblies in the overlying water and sediments of tidal flat aquaculture areas have not been fully explored. Thus, antibiotic concentrations, ARG abundances, microbial communities and the influences of environmental factors in the Jiangsu tidal flat aquaculture ponds were investigated using high-throughput sequencing and qPCR. The concentrations of antibiotics at sampling ranged from not detectable to 2322.4 ng g-1, and sulfamethazine and ciprofloxacin were the dominant antibiotics. The sul1 and sul2 abundances were highest and the ARG abundances were higher in sediment than in water. Meanwhile, bacterial community diversities and structures were significantly different (P < 0.05) between water and sediment samples. Network analysis identified Sphingomonadacear, Pseudomonas, and Xanthobacteraceae as potential ARG-carrying pathogens. A positive correlation between ARGs and intI1 indicated that horizontal gene transfer occurred in water, while antibiotics and TN significantly influenced ARG abundances in sediment. Neutral modeling showed that deterministic and stochastic processes contributed most to the bacterial community assemblies of water and sediment samples, respectively. This study comprehensively illustrates the prevalence of ARGs in intensive tidal flat aquaculture regions and provides an effective foundation for the management of antibiotics usage.

Research Progress Related to Aflatoxin Contamination and Prevention and Control of Soils.

Aflatoxins are potent carcinogenic compounds, mainly produced by fungi species of the genus Aspergillus in the soil. Because of their stability, they are difficult to remove completely, even under extreme conditions. Aflatoxin contamination is one of the main causes of safety in peanuts, maize, wheat and other agricultural products. Aflatoxin contamination originates from the soil. Through the investigation of soil properties and soil microbial distribution, the sources of aflatoxin are identified, aflatoxin contamination is classified and analysed, and post-harvest crop detoxification and corresponding contamination prevention measures are identified. This includes the team's recent development of the biofungicide ARC-BBBE (Aflatoxin Rhizobia Couple-B. amyloliquefaciens, B. laterosporu, B. mucilaginosus, E. ludwiggi) for field application and nanomaterials for post-production detoxification of cereals and oilseed crops, providing an effective and feasible approach for the prevention and control of aflatoxin contamination. Finally, it is hoped that effective preventive and control measures can be applied to a large number of cereal and oilseed crops.

Panax notoginseng-microbiota interactions: From plant cultivation to medicinal application.

BACKGROUND: Microbiomes and their host plants are closely linked with each other; for example, the microbiome affects plant growth, fitness, nutrient uptake, stress tolerance and pathogen resistance, whereas the host plant supports the photosynthetically carbon-rich nutrition of the microbiome. The importance of the microbiome in plant‒soil ecosystems is unquestioned and has expanded to influence the medicinal application of some herbal plants via the gut microbiota. PURPOSE: Herbal plant-microbiome interactions may provide novel knowledge to enhance the robustness of herbal plant crop performance and medicinal applications, which requires a systematic review and preceding discussion. STUDY DESIGN AND METHODS: The interactions between Panax notoginseng and microorganisms (from soil to host) were reviewed from the literature. The terms "Panax notoginseng" and "microbiota" were used in combination with the keywords "microbiota/microbes", "bacteria/bacterium" or "fungi/fungus" or "endophyte", as well as our targeted bioactive phytochemicals, including saponins and ginsenosides. RESULT: Our study focuses on the famous medicinal herb Panax notoginseng F. H. Chen and proposes that the microbiota is a crucial participant not only in the cultivation of this herbal plant but also in its medicinal application. We also summarize and discuss how these plant‒microbe co-associations shape the assembly of plant-related microbiomes and produce bioactive phytochemicals, as well as influence beneficial herbal traits, such as herbal plant health and pharmacology. In addition, we also highlight future directions. CONCLUSION: The rhizosphere and endophytic microbiome of Panax notoginseng are indirectly or directly involved in plant health, biomass production, and the synthesis/biotransformation of plant secondary metabolites. Harnessing the microbiome to improve the quality of traditional Chinese medicine and improve the value of medicinal plants for human health is highly promising.

Ablation of collagen XII disturbs joint extracellular matrix organization and causes patellar subluxation.

Collagen XII, belonging to the fibril-associated collagens, is a homotrimeric secreted extracellular matrix (ECM) protein encoded by the COL12A1 gene. Mutations in the human COL12A1 gene cause an Ehlers-Danlos/myopathy overlap syndrome leading to skeletal abnormalities and muscle weakness. Here, we studied the role of collagen XII in joint pathophysiology by analyzing collagen XII deficient mice and human patients. We found that collagen XII is widely expressed across multiple connective tissue of the developing joint. Lack of collagen XII in mice destabilizes tendons and the femoral trochlear groove to induce patellar subluxation in the patellofemoral joint. These changes are associated with an ECM damage response in tendon and secondary quadriceps muscle degeneration. Moreover, patellar subluxation was also identified as a clinical feature of human patients with collagen XII deficiency. The results provide an explanation for joint hyperlaxity in mice and human patients with collagen XII deficiency.

Manipulating Microbiota in Inflammatory Bowel Disease Treatment: Clinical and Natural Product Interventions Explored.

Inflammatory bowel disease (IBD) is a complex multifactorial chronic inflammatory disease, that includes Crohn's disease (CD) and ulcerative colitis (UC), having progressively increasing global incidence. Disturbed intestinal flora has been highlighted as an important feature of IBD and offers promising strategies for IBD remedies. A brief overview of the variations occurring in intestinal flora during IBD is presented, and the role of the gut microbiota in intestinal barrier maintenance, immune and metabolic regulation, and the absorption and supply of nutrients is reviewed. More importantly, we review drug research on gut microbiota in the past ten years, including research on clinical and natural drugs, as well as adjuvant therapies, such as Fecal Microbiota Transplantation and probiotic supplements. We also summarize the interventions and mechanisms of these drugs on gut microbiota.

Unraveling antibiotic resistomes associated with bacterial and viral communities in intertidal mudflat aquaculture area.

The extensive use of antibiotics in intertidal mudflat aquaculture area has substantially increased the dissemination risk of antibiotic resistance genes (ARGs). As hosts of ARGs, bacteria and virus exert vital effects on ARG dissemination. However, the insights for the interrelationships among ARGs, bacteria, and virus have not been thoroughly explored in intertidal mudflat. Therefore, this study attempts to unravel the occurrence, dissemination, evolution, and driving mechanisms of ARGs associated with bacterial and viral communities using metagenomic sequencing in a typical intertidal mudflat. Abundant and diverse ARGs (22 types and 437 subtypes) were identified and those of ARGs were higher in spring than in autumn. It is worthy noted that virus occupied a more essential position than bacteria for ARGs dissemination through network analysis. Meanwhile, nitrogen exerted indirect effect on ARG profiles by shaping viral and bacterial diversity. According to the results of neutral and null models, deterministic processes dominated the ARG community assembly by controlling sediment nitrogen and antibiotics. Homogeneous and variable selection dominated phylogenetic turnover of ARG community, contributing 46.15% and 45.90% of the total processes, respectively. This study can hence theoretically support for the ARG pollution control and management in intertidal mudflat aquaculture area.

Assessing the effects of aquaculture on tidal flat ecological status using multi-metrics interaction-based index of biotic integrity (Mt-IBI).

Given tidal flat special environmental conditions and the degree of pollution caused by human activities, there is an urgent need to quantitatively assess their ecological status. Bioindication has become an indispensable part of environmental quality monitoring on account of its sensitivity to environmental disturbance. Thus, this study used bio-indicators to establish a multi-metrics-based index of biotic integrity (Mt-IBI) to evaluate the ecological status of the tidal flats with/without aquaculture through metagenomic sequencing. Four core indexes that were significantly correlated to other indexes with redundancy (p < 0.05), including Escherichia, beta-lactam antibiotic resistance genes, cellulase and xyloglucanases and the keystone species with 21° in the network, were selected after the screening processes. By implementing Mt-IBI in the tidal flats, the ecological health of the sampling sites was categorized into three levels, with Mt-IBI values of 2.01-2.63 (severe level), 2.81-2.93 (moderate level) and 3.23-4.18 (mild level), respectively. Through SEM analysis, water chemical oxygen demand and antibiotics were determined to be the primary controlling factors of the ecological status of tidal flat regions influenced by aquaculture, followed by salinity and total nitrogen. It is worth noting that the alteration of microbial communities impacted ecological status through the mediation of antibiotics. It is hoped that the results of our study will provide a theoretical basis for coastal environment restoration and that the use of Mt-IBI to assess ecosystem status in different aquatic environments will be further popularized in the future.

Cytotoxic 4-phenylcoumarins from the flowering buds of Mesua ferrea.

Eleven 4-phenylcoumarins including three new 4-phenylcoumarins, mesuaferols A-C (1-3), together with eight known 4-phenylcoumarins (4-11) have been isolated from the flowering buds of Mesua ferrea. Their structures were elucidated via UV, IR, HR-ESI-MS, and NMR spectral data. Compound 9 showed moderate cytotoxic activity toward MDA-MB-231, MCF-7, HepG2 and HeLa cell lines with IC50 values of 13.68 ± 1.36 µM, 9.27 ± 1.84 µM, 21.06 ± 1.95 µM, and 7.26 ± 1.68 µM, respectively, and other compounds showed weak cytotoxicity.

Real-time detection of Seneca Valley virus by one-tube RPA-CRISPR/Cas12a assay.

Introduction: Senecavirus A (SVA) is a highly contagious virus that causes vesicular disease in pigs. At present, laboratory detection methods, such as virus isolation and polymerase chain reaction (PCR), required precision instruments and qualified personnel, making them unsuitable for point-of-care tests (POCT). Fortunately, the emergence of CRISPR/Cas system has provided new opportunities for fast and efficient pathogen detection. Methods: This study successfully developed a precise and sensitive detection platform for diagnosing SVA by combining the CRISPR system with recombinase polymerase amplification (RPA). Results: The minimum detection limit of the assay was 10 copies of the SVA genome. Meanwhile, the assay demonstrated high specificity. To validate the effectiveness of this system, we tested 85 swine clinical samples and found that the fluorescence method had a 100% coincidence rate compared to RT-qPCR. Discussion: Overall, the RPA-CRISPR/Cas12a assay established in our study is a highly effective method for detecting SVA and holds great potential for practical applications in the resource-limited settings.

Visual detection of Mycoplasma pneumoniae by the recombinase polymerase amplification assay coupled with lateral flow dipstick.

Mycoplasma pneumoniae (Mp) is a common cause of respiratory infections in school-age children. In the present study, a recombinase polymerase amplification (RPA) assay combined with lateral flow dipstick (LFD) was developed for diagnosis of Mp. Specific primers and a probe were designed for the Mp p1 gene. The optimal reaction conditions of the RPA-LFD assay were 37 °C and 25 min. The minimal detection limit of the RPA assay was 10 DNA molecules. The RPA method had no cross-reaction with the other 14 common pathogens tested. The practicability of the assay for detecting Mp in clinical samples from the patients suspected to be Mp infection was also determined. The nucleic acids of the clinical samples were extracted by the DNA Rapid extraction reagent which took about 10 min. The clinical specimens were detected by the RPA method, and the result showed high agreement with that of the qPCR commercial kit. The RPA-LFD method with high sensitivity and specificity is easy to perform and is an alternative method for field detection in resources-limited settings.

[Advances of CRISPR/Cas9 activation system].

Gene editing technology has been a hotspot in the field of biotechnology. CRISPR/Cas systems are efficient gene editing tools because of its specificity, simplicity and flexibility, these features enabled the rapid application of CRISPR/Cas systems in a variety of organisms. Moreover, the combination of transcriptional activator with dead Cas protein can achieve specific regulation of gene expression at the transcription level, which has made important contributions to the development of biotechnology in medical and agriculture. Overexpression of foreign genes is a common method to verify gene function and regulation. However, due to the limitation of vector capacity, it is difficult to achieve overexpression of multiple genes. CRISPR/Cas9 activation system can regulate the expression of multiple genes under the guidance of different guide RNAs to verify gene functions at the regulatory level. This review summarizes the composition of the CRISPR/Cas9 activation system and different activation strategies, and summarizes solutions for excessive activation. It may facilitate the application of CRISPR/Cas9 activation system in genetic improvement of cotton and herbicide resistance research.

Discovery of the Relationship between Distribution and Aflatoxin Production Capacity of Aspergillusspecies and Soil Types in Peanut Planting Areas.

In order to study the relationship between the distribution and aflatoxin production capacity of Aspergillus species and soil types, 35 soil samples were collected from the main peanut planting areas in Xiangyang, which has 19.7 thousand square kilometers and is located in a special area with different soil types. The soil types of peanut planting areas in Xiangyang are mainly sandy loam and clay loam, and most of the soil is acidic, providing unique nature conditions for this study. The results showed that the Aspergillus sp. population in clay loam (9050 cfu/g) was significantly larger than that in sandy loam (3080 cfu/g). The percentage of atoxigenic Aspergillus strains isolated from sandy loam samples was higher than that from clay loam samples, reaching 58.5%. Meanwhile the proportion of high toxin-producing strains from clay loam (39.7%) was much higher than that from sandy loam (7.3%). Under suitable culture conditions, the average aflatoxin production capacity of Aspergillus isolates from clay loam samples (236.97 µg/L) was higher than that of strains from sandy loam samples (80.01 µg/L). The results inferred that under the same regional climate conditions, the density and aflatoxin production capacity of Aspergillus sp. in clay loam soil were significantly higher than that in sandy loam soil. Therefore, peanuts from these planting areas are at a relatively higher risk of contamination by Aspergillus sp. and aflatoxins.

Deterministic assembly process dominates bacterial antibiotic resistome in wastewater effluents receiving river.

Antibiotic resistance has become a concerning global health challenge, such as the dissemination of bacteria and genes between humans and the environments. Wastewater treatment plants (WWTPs) effluents, as significant reservoirs for antimicrobial resistant bacteria and antibiotic resistance genes (ARGs), pose critical risks to public health. However, whether wastewater effluent prominently contributes to the abundance of ARGs and their community assembly processes in receiving river has yet been unclear. Here we investigated the effects of the effluent discharge on the ARGs and their associate microbial community in the receiving river (Qinhuai River, Nanjing) of upstream and 2000 m downstream of one WWTPs discharge point. Results revealed that the total antibiotic concentrations of all sediment samples ranged from 37.86 to 76.11 µg/kg dw, while antibiotic concentrations and ARG abundances in the river near the wastewater discharge site were significantly higher than that of the downstream receiving river. The metagenomic assembly obtained 245 ARGs associated with 19 antibiotic types in the receiving river. Network analyses confirmed that Proteobacteria, Firmicutes, Acidobacteria, and Bacteroides were the key phylum and positively correlated with the antibiotic resistome. Additionally, the bacterial pathogens of the receiving river were identified as the most frequent strains of clinically relevant antibacterial resistance, such as Streptococcus pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Using null modeling analysis to determine the quantification of ecological processes, the results showed that heterogeneous environmental selection (81.81%) was a dominate role of the ecological mechanisms determining the ARG community reconstruction in the receiving river. Our results may contribute to control the environmental dissemination of antimicrobial resistance risks in aquatic environments.

Ablation of the miRNA cluster 24 in cartilage and osteoblasts impairs bone remodeling.

MicroRNAs (miRNAs) post-transcriptionally regulate cartilage and bone development and function, however, only few miRNAs have been described to play a role for cartilage to bone transition in vivo. Previously, we showed that cartilage-specific deletion of the Mirc24 cluster in newborn male mice leads to impaired growth plate cartilage development due to increased RAF/MEK/ERK signaling and affects the stability of the cartilage extracellular matrix on account of decreased SOX6 and SOX9 and increased MMP13 levels. Here, we studied how Mirc24 cluster inactivation in cartilage and osteoblasts leads to an increased bone density associated with defects in collagen remodeling in trabecular bone. No changes in osteoblast distribution were observed, whereas the number of osteoclasts was reduced and TRAP activity in osteoclasts decreased. Surprisingly, an increased level of cluster-encoded miR-322 or miR-503 raises Rankl gene expression and inactivation of the cluster in chondrocytes reduces Rankl expression. These results suggest that the Mirc24 cluster regulates Rankl expression in chondrocytes at the chondro-osseous border, where the cluster is mainly expressed to modulate osteoclast formation, bone remodeling and bone integrity.

Visual detection of porcine epidemic diarrhea virus by recombinase polymerase amplification combined with lateral flow dipstrip.

BACKGROUND: Porcine epidemic diarrhea virus (PEDV) is one of the most important enteric viruses causing diarrhea in pigs. The establishment of a rapid detection method applicable in field conditions will be conducive to early detection of pathogen and implementation of relevant treatment. A novel nucleic acid amplification method, recombinase polymerase amplification (RPA), has been widely used for infectious disease diagnosis. RESULTS: In the present study, a reverse transcription (RT)-RPA assay combined with lateral flow dipstrip (LFD) was established for the visual detection of PEDV by targeting the N gene. The RT-RPA-LFD assay detected as low as 102 copies/µL of PEDV genomic RNA standard. Moreover, the novel RT-RPA-LFD assay did not show cross-reactivity with common swine pathogens, demonstrating high specificity. The performance of the assay for detection of clinical samples was also evaluated. A total number of 86 clinical samples were tested by RT-RPA-LFD and RT-PCR. The detection results of RT-RPA-LFD were compared with those of RT-PCR, with a coincidence rate of 96.5%. CONCLUSION: The newly established RT-RPA-LFD assay in our study had high sensitivity and specificity, with a potential to use in resource-limited areas and countries.

Tidal flat aquaculture pollution governs sedimentary antibiotic resistance gene profiles but not bacterial community based on metagenomic data.

Coastal tidal flats are intersection zones between terrestrial and marine environments and are considered repositories of pollutants from anthropogenic activities (e.g., fishery and aquaculture). Specifically, the prevalence of antibiotics and antibiotic resistance genes (ARGs) in coastal aquaculture environments pose critical threats to estuarine ecosystems. However, the contribution of aquaculture to the occurrence and abundance of ARGs and community assemblies has not been fully explored in tidal flat zones. Thus, we investigated ARGs profiles, ARG-carrying host bacteria, and their associate microbial community in the Dongtai and Sheyang tidal flat aquaculture regions of Jiangsu, China using metagenomic assembly methods. The antibiotic concentrations in the sediment samples ranged from nd to 35.50 ng/g dw, and the antibiotic pollution in the Dongtai tidal flat was more severe than in the Sheyang tidal flats. Metagenomic assembly indicated that a total of 247 ARG subtypes associated with ARG 33 types were characterized across all samples and their abundance in the Dongtai region exceeded that in the Sheyang region. Meanwhile, 21 bacteria in the tidal flat aquaculture were identified as ARG-carrying pathogens, including Escherichia coli, Vibrio fluvialis, and Staphylococcus aureus. Using neutral and null modeling analysis to determine the community ecological processes, the results revealed bacterial and ARG communities were generally dominated by stochastic and deterministic processes, respectively. The above results suggested that aquaculture pollution was contributed to shape ARG profiles in tidal flats. The observed deterministic processes affecting the ARG community in tidal flat aquaculture also provides an effective foundation to control the risks of environmental antibiotic resistance through reducing aquaculture antibiotic usage.

Determination of the direct and indirect effects of bend on the urban river ecological heterogeneity.

The ecological heterogeneity created by river bends benefits the diversity of microorganisms, which is vital for the pollutant degradation and overall river health. However, quantitative tools capable of determining the interactions among different trophic levels and species are lacking, and research regarding ecological heterogeneity has been limited to a few species. By integrating the multi-species-based index of biotic integrity (Mt-IBI) and the structure equation model (SEM), an interactions-based prediction modeling framework was established. Based on DNA metabarcoding, a multi-species (i.e., bacteria, protozoans, and metazoans) based index of biotic integrity including 309 candidate metrics was developed. After a three-step screening process, eight core metrics were obtained to assess the ecological heterogeneity, quantitatively. The Mt-IBI value, which ranged from 2.08 to 7.17, was calculated as the sum of each single core metric value. The Mt-IBI revealed that the ecological heterogeneity of concave banks was higher than other sites. According to the result of the SEM, D90 was the controlling factor (r = -0.779) of the ecological heterogeneity under the influence of the river bends. The bend-induced redistribution of sediment particle further influenced the concentrations of carbon, nitrogen, and sulphur. The nitrogen group (r = 0.668) also played an essential role in determining the ecological heterogeneity, follow by carbon group (r = 0.455). Furthermore, the alteration of niches would make a difference on the ecological heterogeneity. This multi-species interactions-based prediction modeling framework proposed a novel method to quantify ecological heterogeneity and provided insight into the enhancement of ecological heterogeneity in river bends.