A review of distribution and functions of extracellular DNA in the environment and wastewater treatment systems.

Extracellular DNA refers to DNA fragments existing outside the cell, originating from various cell release mechanisms, including active secretion, cell lysis, and phage-mediated processes. Extracellular DNA serves as a vital environmental biomarker, playing crucial ecological and environmental roles in water bodies. This review is summarized the mechanisms of extracellular DNA release, including pathways involving cell lysis, extracellular vesicles, and type IV secretion systems. Then, the extraction and detection methods of extracellular DNA from water, soil, and biofilm are described and analyzed. Finally, we emphasize the role of extracellular DNA in microbial community systems, including its significant contributions to biofilm formation, biodiversity through horizontal gene transfer, and electron transfer processes. This review offers a comprehensive insight into the sources, distribution, functions, and impacts of extracellular DNA within aquatic environments, aiming to foster further exploration and understanding of extracellular DNA dynamics in aquatic environments as well as other environments.

Recovery strategies and mechanisms of anammox reaction following inhibition by environmental factors: A review.

Anaerobic ammonium oxidation (anammox) is a promising biological method for treating nitrogen-rich, low-carbon wastewater. However, the application of anammox technology in actual engineering is easily limited by environmental factors. Considerable progress has been investigated in recent years in anammox restoration strategies, significantly addressing the challenge of poor reaction performance following inhibition. This review systematically outlines the strategies employed to recover anammox performance following inhibition by conventional environmental factors and emerging pollutants. Additionally, comprehensive summaries of strategies aimed at promoting anammox activity and enhancing nitrogen removal performance provide valuable insights into the current research landscape in this field. The review contributes to a comprehensive understanding of restoration strategies of anammox-based technologies.

Effect of biochar on the SPNA system at ambient temperatures.

Biochar has been extensively studied in wastewater treatment systems. However, the role of biochar in the single-stage partial nitritation anammox (SPNA) system remains not fully understood. This study explored the impact of biochar on the SPNA at ambient temperatures (20 °C and 15 °C). The nitrogen removal rate of the system raised from 0.43 to 0.50 g N/(L·d) as the biochar addition was raised from 2 to 4 g/L. Metagenomic analysis revealed that gene abundances of amino sugar metabolism and nucleotide sugar metabolism, amino acid metabolism, and quorum sensing were decreased after the addition of biochar. However, the gene abundance of enzymes synthesizing NADH and trehalose increased, indicating that biochar could stimulate electron transfer reactions in microbial metabolism and assist microorganisms in maintaining a steady state at lower temperatures. The findings of this study provide valuable insights into the mechanism behind the improved nitrogen removal facilitated by biochar in the single-stage partial nitritation anammox system.

The effects and mechanisms of modified Xiaoyaosan on chronic unpredictable mild stress (CUMS)-induced depressive mice based on network pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: Clinical research and basic scientific experiments have shown that modified Xiaoyaosan (MXYS) has antidepressant effects, whose system mechanism however has not been thoroughly characterized. AIM OF THE STUDY: This research was aimed at evaluating the treatment effects of MXYS on chronic unpredictable mild stress (CUMS)-induced depressive mice and exploring underlying mechanisms. MATERIALS AND METHODS: Whether MXYS has effects on depression was investigated via the depressive behaviors of mice, electron microscopy, real-time quantitative polymerase chain reaction (RT-qPCR), Western blot analysis, immunofluorescence (IF) staining and the stereotaxic injection of adeno-associated viruses (AAVs). In addition, network pharmacology was applied to predict relevant molecular targets and possible mechanisms and perform further in vivo validation. RESULTS: MXYS is effective in ameliorating the depression-like symptoms of CUMS mice. It can stimulate autophagosome formation, activate the expression of microtubule-associated protein 1 light chain 3 (LC3B), autophagy-related gene 5 (Atg5), Atg7 and neuron-specific nuclear protein (NeuN), and decrease the protein expression sequestosome 1 (SQSTM1/p62). The autophagy-upregulating effect of MXYS was weakened by silencing. The network pharmacology analysis revealed that mitogen-activated protein kinase 1 (MAPK1), MAPK3, serine/threonine-protein kinase (AKT1), proto-oncogene tyrosine-protein kinase (SRC), PI 3 kinase p85 alpha (PIK3R1), catenin (cadherin-associated protein) beta 1 (CTNNB1) and human thrombin activator 1 (HRAS) may be of importance to treat depression by MXYS. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that metabolic and autophagy pathways, pathways in cancer and MAPK, phosphoinositide 3-kinase (PI3K)-Akt and rhoptry-associated protein 1 (Rap1) signaling pathways are involved in the antidepressant effects of MXYS. As suggested by Western blot, the anti-depression mechanism of MXYS is possibly associated with the extracellular signal-regulated protein kinase (ERK)/P38 MAPK signaling pathway. CONCLUSION: The findings indicate the possible antidepressant effects of MXYS on CUMS mice via triggering autophagy to alleviate neuronal apoptosis and prompting autophagy, which may involve the ERK/P38 MAPK signaling pathway.

A soil fumigant increases American ginseng (Panax quinquefolius L.) survival and growth under continuous cropping by affecting soil microbiome assembly: a 4-year in situ field experiment.

IMPORTANCE: Numerous reports of soil fumigants and fungicides on annual crops exist; however, it is unclear whether the single application to perennial plants persistently improves plant growth and controls disease or whether it has a long-lasting impact on soil microbes. We found that soil fumigation enhances ginseng growth and suppresses root rot disease by reshaping the soil microbial community. Our findings benefit the agricultural development of ginseng and provide a theoretical basis for the prevention of ginseng diseases.

Extracellular polymeric substances and microbial community shift during the start-up of a single-stage partial nitritation/anammox process.

A sequencing batch reactor (SBR) was operated to investigate variations of extracellular polymeric substances (EPS) and microbial community during the start-up of the single-stage partial nitritation/anammox (SPN/A) process at intermittent aeration mode. The SPN/A system was successfully started on day 34, and the nitrogen removal efficiency and total nitrogen loading rate were 82.29% and 0.31 kg N/(m3 ·day), respectively. Furthermore, the relationship between the protein secondary structures and microbial aggregation was strongly related. The α-helix/ (ß-sheet + random coil) ratios increased obviously from 0.20 ± 0.03 to 0.23 ± 0.01, with the sludge aggregation mean size increased from 56 to 107 µm during the start-up of SPN/A. During the start-up of SPN/A, Candidatus Kuenenia was the primary anammox bacteria, whereas Nitrospira was the main functional bacteria of nitrite-oxidizing bacteria. Correlation between the microbial community and EPS components was performed. The EPS and microbial community played important roles in keeping stable nitrogen removal and the formation of sludge granules. PRACTITIONER POINTS: Intermittent aeration strategy promoted SPN/A system start-up. EPS composition and protein secondary structure were related with the sludge disintegration and aggregation. Microbial community shift existed and promoted the stability of sludge and reactor performance during SPN/A start-up.

Abnormal voxel-mirrored homotopic connectivity in first-episode major depressive disorder using fMRI: a machine learning approach.

Objective: To explore the interhemispheric information synergy ability of the brain in major depressive disorder (MDD) patients by applying the voxel-mirrored homotopic connectivity (VMHC) method and further explore the potential clinical diagnostic value of VMHC metric by a machine learning approach. Methods: 52 healthy controls and 48 first-episode MDD patients were recruited in the study. We performed neuropsychological tests and resting-state fMRI scanning on all subjects. The VMHC values of the symmetrical interhemispheric voxels in the whole brain were calculated. The VMHC alterations were compared between two groups, and the relationship between VMHC values and clinical variables was analyzed. Then, abnormal brain regions were selected as features to conduct the classification model by using the support vector machine (SVM) approach. Results: Compared to the healthy controls, MDD patients exhibited decreased VMHC values in the bilateral middle frontal gyrus, fusiform gyrus, medial superior frontal gyrus and precentral gyrus. Furthermore, the VMHC value of the bilateral fusiform gyrus was positively correlated with the total Hamilton Depression Scale (HAMD). Moreover, SVM analysis displayed that a combination of all clusters demonstrated the highest area under the curve (AUC) of 0.87 with accuracy, sensitivity, and specificity values of 86.17%, 76.74%, and 94.12%, respectively. Conclusion: MDD patients had reduced functional connectivity in the bilateral middle frontal gyrus, fusiform gyrus, medial superior frontal gyrus and precentral gyrus, which may be related to depressive symptoms. The abnormality in these brain regions could represent potential imaging markers to distinguish MDD patients from healthy controls.

The relationship between shifts in the rhizosphere microbial community and root rot disease in a continuous cropping American ginseng system.

The root rot disease causes a great economic loss, and the disease severity usually increases as ginseng ages. However, it is still unclear whether the disease severity is related to changes in microorganisms during the entire growing stage of American ginseng. The present study examined the microbial community in the rhizosphere and the chemical properties of the soil in 1-4-year-old ginseng plants grown in different seasons at two different sites. Additionally, the study investigated ginseng plants' root rot disease index (DI). The results showed that the DI of ginseng increased 2.2 times in one sampling site and 4.7 times in another during the 4 years. With respect to the microbial community, the bacterial diversity increased with the seasons in the first, third, and fourth years but remained steady in the second year. The seasonal changing of relative abundances of bacteria and fungi showed the same trend in the first, third, and fourth years but not in the second year. Linear models revealed that the relative abundances of Blastococcus, Symbiobacterium, Goffeauzyma, Entoloma, Staphylotrichum, Gymnomyces, Hirsutella, Penicillium and Suillus spp. were negatively correlated with DI, while the relative abundance of Pandoraea, Rhizomicrobium, Hebeloma, Elaphomyces, Pseudeurotium, Fusarium, Geomyces, Polyscytalum, Remersonia, Rhizopus, Acremonium, Paraphaeosphaeria, Mortierella, and Metarhizium spp. were positively correlated with DI (P < 0.05). The Mantel test showed that soil chemical properties, including available nitrogen, phosphorus, potassium, calcium, magnesium, organic matter, and pH, were significantly correlated to microbial composition. The contents of available potassium and nitrogen were positively correlated with DI, while pH and organic matter were negatively correlated with DI. In summary, we can deduce that the second year is the key period for the shift of the American ginseng rhizosphere microbial community. Disease aggravation after the third year is related to the deterioration of the rhizosphere microecosystem.

A review of anammox metabolic response to environmental factors: Characteristics and mechanisms.

Anaerobic ammonium oxidation (anammox) is a promising low carbon and economic biological nitrogen removal technology. Considering the anammox technology has been easily restricted by environmental factors in practical engineering applications, therefore, it is necessary to understand the metabolic response characteristics of anammox bacteria to different environmental factors, and then guide the application of the anammox process. This review presented the latest advances of the research progress of the effects of different environmental factors on the metabolic pathway of anammox bacteria. The effects as well as mechanisms of conventional environmental factors and emerging pollutants on the anammox metabolic processes were summarized. Also, the role of quorum sensing (QS) mediating the bacteria growth, gene expression and other metabolic process in the anammox system were also reviewed. Finally, interaction and cross-feeding mechanisms of microbial communities in the anammox system were discussed. This review systematically summarized the variations of metabolic mechanism response to the external environment and cross-feeding interactions in the anammox process, which would provide an in-depth understanding for the anammox metabolic process and a comprehensive guidance for future anammox-related metabolic studies and engineering applications.

Regional amplitude abnormities in the major depressive disorder: A resting-state fMRI study and support vector machine analysis.

PURPOSE: Major depressive disorder (MDD) is a common mood disorder. However, it still remains challenging to select sensitive biomarkers and establish reliable diagnosis methods currently. This study aimed to investigate the abnormalities of the spontaneous brain activity in the MDD and explore the clinical diagnostic value of three amplitude metrics in altered regions by applying the support vector machine (SVM) method. METHODS: A total of fifty-two HCs and forty-eight MDD patients were recruited in the study. The amplitude of low-frequency fluctuation (ALFF), fractional amplitude of low-frequency fluctuation (fALFF) and percent amplitude of fluctuation (PerAF) metrics were calculated to assess local spontaneous brain activity. Then we performed correlation analysis to examine the association between cerebral abnormalities and clinical characteristics. Finally, SVM analysis was applied to conduct the classification model for evaluating the diagnostic value. RESULTS: Two-sample t-test exhibited that MDD patients had increased ALFF value in the right caudate and corpus callosum, increased fALFF value in the same regions and increased PerAF value in the inferior parietal lobule and right caudate compared to HCs. Moreover, PerAF value in the inferior parietal lobule was negatively correlated with the slow factor scores. The SVM results showed that a combination of mean ALFF and fALFF in the right caudate and corpus callosum selected as features achieved a highest area under curve (AUC) value (0.89), accuracy (79.79%), sensitivity (65.12%) and specificity (92.16%). CONCLUSION: Collectively, we found increased mean ALFF and fALFF may serve as a potential neuroimaging marker to discriminate MDD and HCs.

Effect of filamentous algae in a microalgal-bacterial granular sludge system treating saline wastewater: Assessing stability, lipid production and nutrients removal.

In this study modified microalgal-bacterial granular sludge (MBGS) was constructed and employed to compare the performance for treating 1%-5% saline wastewater with aerobic granular sludge (AGS). Filamentous algae were found to flourish at 1% salinity when nutrients were temporarily restricted to low level (COD 0, N 10 mg/L, P 0.5 mg/L). A significant improvement of granule stability was detected as the integrity coefficients of MBGS was only 0.12-0.24 rather than 0.19-0.48 of AGS under 1%-5% salinities, which reduced the risk of particle disintegration. Filamentous algae including Leptolyngbya and Geitlerinema occupied 91.2% of identified algae, and were beneficial for enhancing the biomass content and lipid production to about 1.27-1.37, 3.1-5.0 times than AGS. The MBGS had best nitrogen and phosphorus removal efficiencies of 93.4% and 64.6% at 1% salinity, and showed higher resistance to 3%-5% salinities. This study could provide meaningful information for using this modified MBGS technology in practice.

A bZIP transcription factor, PqbZIP1, is involved in the plant defense response of American ginseng.

American ginseng (Panax quinquefolius L.) is a perennial medicinal plant that has a long usage history in China. However, root rot, which is mainly caused by Fusarium solani can severely reduce the yield and quality of American ginseng, but no disease-resistant variety of American ginseng exists, and the resistance against this disease is not yet well understood. Thus, it is very urgent to analyze the interaction mechanism regulating the interactions between American ginseng and F. solani to mine disease resistance genes. Using transcriptome data and quantitative polymerase chain reaction (qPCR), we screened the transcription factor PqbZIP1 in response to induction by chitin. Yeast self-activation and subcellular localization experiments proved that PqbZIP1 showed transcriptional activity and was localized in the plant nucleus. In addition, qPCR showed that the highest relative expression level was in the roots, wherein chitin and F. solani inhibited and activated the expression of PqbZIP1, respectively, in American ginseng. Additionally, PqbZIP1 significantly inhibited the growth of the Pseudomonas syringae pv. tomato D36E strain in Nicotiana benthamiana, where expressing PqbZIP1 in N. benthamiana increased the jasmonic acid, salicylic acid, and abscisic acid content. Furthermore, PqbZIP1 expression was continually increased upon inoculation with F. solani. Hence, this study revealed that the PqbZIP1 transcription factor might mediate multiple hormonal signaling pathway to modulate root rot disease resistance in American ginseng, and provided important information to breed disease-resistant American ginseng.

Ethyl Acetate Fraction of Dicliptera chinensis (L.) Juss. Ameliorates Liver Fibrosis by Inducing Autophagy via PI3K/AKT/mTOR/p70S6K Signaling Pathway.

OBJECTIVE: To investigate the molecular mechanism underlying the anti-hepatic fibrosis activity of ethyl acetate fraction Dicliptera chinensis (L.) Juss. (EDC) in human hepatic stellate cells (HSCs) in vitro and in a carbon tetrachloride (CCl4)-induced hepatic fibrosis mouse model in vivo. METHODS: For in vitro study, HSCs were pre-treated with platelet-derived growth factor (10 ng/mL) for 2 h to ensure activation and treated with EDC for 24 h and 48 h, respectively. The effect of EDC on HSCs was assessed using cell counting kit-8 assay, EdU staining, transmission electron microscopy, immunofluorescence staining, and Western blot, respectively. For in vivo experiments, mice were intraperitoneally injected with CCl4 (2 ° L/g, adjusted to a 25% concentration in olive oil), 3 times per week for 6 weeks, to develop a hepatic fibrosis model. Forty 8-week-old male C57BL/6 mice were divided into 4 groups using a random number table (n=10), including control, model, positive control and EDC treatment groups. Mice in the EDC and colchicine groups were intragastrically administered EDC (0.5 g/kg) or colchicine (0.2 mg/kg) once per day for 6 weeks. Mice in the control and model groups received an equal volume of saline. Biochemical assays and histological examinations were used to assess liver damage. Protein expression levels of α -smooth muscle actin (α -SMA) and microtubule-associated protein light chain 3B (LC3B) were measured by Western blot. RESULTS: EDC reduced pathological damage associated with liver fibrosis, downregulated the expression of α -SMA and upregulated the expression of LC3B (P<0.05), both in HSCs and the CCl4-induced liver fibrosis mouse model. The intervention of bafilomycin A1 and rapamycin in HSCs strongly supported the notion that inhibition of autophagy enhanced α -SMA protein expression levels (P<0.01). The results also found that the levels of phosphoinositide (PI3K), p-PI3K, AKT, p-AKT, mammalian target of rapamycin (mTOR), p-mTOR, and p-p70S6K all decreased after EDC treatment (P<0.05). CONCLUSIONS: EDC has anti-hepatic fibrosis activity by inducing autophagy and might be a potential drug to be further developed for human liver fibrosis therapy.

Combined rs-fMRI study on brain functional imaging and mechanism of RAGE-DAMPs of depression: Evidence from MDD patients to chronic stress-induced depression models in cynomolgus monkeys and mice.

More and more evidence show that major depressive disorder (MDD) is closely related to inflammation caused by chronic stress, which seriously affects human physical and mental health. However, the inflammatory mechanism of depression and its effect on brain function have not been clarified. Based on resting-state functional magnetic resonance imaging (rs-fMRI), we investigated change of brain functional imaging and the inflammatory mechanism of damage-related molecular patterns (DAMPs)-receptor of advanced glycation protein end product (RAGE) in MDD patients and depressive-like cynomolgus monkeys and mice models induced by chronic stress. The regional homogeneity (ReHo) and functional connectivity (FC) were analyzed using MATLAB and SPM12 software. We detected the expression of DAMPs-RAGE pathway-related proteins and mRNA in MDD peripheral blood and in serum and brain tissue of cynomolgus monkeys and mice. Meanwhile, RAGE gene knockout mice, RAGE inhibitor, and overexpression of AVV9RAGE adeno-associated virus were used to verify that RAGE is a reliable potential biomarker of depression. The results showed that the ReHo value of prefrontal cortex (PFC) in MDD patients and depressive-like cynomolgus monkeys was decreased. Then, the PFC was used as a seed point, the FC of ipsilateral and contralateral PFC were weakened in depressive-like mice. At the same time, qPCR showed that RAGE and HMGB1 mRNA were upregulated and S100ß mRNA was downregulated. The expression of RAGE-related inflammatory protein in PFC of depressive-like monkeys and mice were consistent with that in peripheral blood of MDD patients. Moreover, the results were confirmed in RAGE-/- mice, injection of FPS-ZM1, and overexpression of AAV9RAGE in mice. To sum up, our findings enhance the evidence that chronic stress-PFC-RAGE are associated with depression. These results attempt to establish the links between brain functional imaging, and molecular targets among different species will help to reveal the pathophysiological mechanism of depression from multiple perspectives.

Application of vermicompost and biochar suppresses Fusarium root rot of replanted American ginseng.

Soil sterilization integrated with agronomic measures is an effective method to reduce soilborne replant diseases. However, the effect of vermicompost or biochar application after soil sterilization on soilborne diseases is poorly understood. A pot experiment was conducted in American ginseng to investigate the effects of vermicompost (VF), biochar (BF), and a combination of vermicompost and biochar (VBF) applied after soil sterilization on the incidence of Fusarium root rot using natural recovery (F) as control. After one growing season, the disease index of root rot, the phenolic acids, and the microbial communities of American ginseng rhizosphere soil were analyzed. The disease index of VF, BF, and VBF decreased by 33.32%, 19.03%, and 80.96%, respectively, compared with F. The highest bacterial richness and diversity were observed in the rhizosphere soil of VBF. Besides, VF and VBF significantly increased the relative abundance of beneficial bacteria (Pseudomonas, Lysobacter, and Chryseolinea) in the rhizosphere soil. Higher concentrations of vanillin, one of the phenolic acids in the roots exudates, were recorded in the rhizosphere soils of BF and VBF. The vanillin concentration showed a significant negative correlation with the disease index. To conclude, vermicompost improved the beneficial bacteria of the rhizosphere soil, while biochar regulated the allelopathic effect of the phenolic acids. The study proposes a combined application of biochar and vermicompost to the rhizosphere soil to control Fusarium root rot of replanted American ginseng effectively. KEY POINTS: Vermicompost improves the relative abundance of rhizosphere beneficial bacteria. Biochar inhibits the degradation of phenolic acids by adsorption. The combination of vermicompost and biochar enhances the disease control effect.

Amynthas corticis genome reveals molecular mechanisms behind global distribution.

Earthworms (Annelida: Crassiclitellata) are widely distributed around the world due to their ancient origination as well as adaptation and invasion after introduction into new habitats over the past few centuries. Herein, we report a 1.2 Gb complete genome assembly of the earthworm Amynthas corticis based on a strategy combining third-generation long-read sequencing and Hi-C mapping. A total of 29,256 protein-coding genes are annotated in this genome. Analysis of resequencing data indicates that this earthworm is a triploid species. Furthermore, gene family evolution analysis shows that comprehensive expansion of gene families in the Amynthas corticis genome has produced more defensive functions compared with other species in Annelida. Quantitative proteomic iTRAQ analysis shows that expression of 147 proteins changed in the body of Amynthas corticis and 16 S rDNA sequencing shows that abundance of 28 microorganisms changed in the gut of Amynthas corticis when the earthworm was incubated with pathogenic Escherichia coli O157:H7. Our genome assembly provides abundant and valuable resources for the earthworm research community, serving as a first step toward uncovering the mysteries of this species, and may provide molecular level indicators of its powerful defensive functions, adaptation to complex environments and invasion ability.

First report of root rot caused by Fusarium armeniacum on American ginseng in China.

American ginseng (Panax quinquefolius) is an important medicinal plant cultivated in China since the 1980s. Its dried roots are used for food, health care products, and medicine in China (Yuan et al. 2010). Root rot caused by Fusarium spp. was a major disease, with 33 to 41% incidence surveyed in main production areas of Wendeng County (121.80 °E, 37.09 °N) in Shandong Province, China in 2016 to 2019. Symptoms included soft, water-soaked, dark brown to black lesions on the roots. Lesions progressed and the inner parts gradually disintegrated. One-year-old diseased roots were collected in September 2016. Symptomatic tissues were surface-sterilized in 75% ethanol for 30 s and 0.8% NaOCl for 3 min, rinsed in sterile water, plated on potato dextrose agar (PDA), and incubated at 25°C in darkness. Single colonies were then obtained and transferred to carnation leaf agar (CLA) (Burgess et al. 1993) for growth at 25°C with a 12-h photoperiod. Colonies cultured on PDA for 7 days were white to light pink, turning to apricot pigmentation in color. After 30 days on CLA, the colonies produced elongate, falcate macroconidia having 3 to 5 septa, with a long, tapering and curved apical cell, and having the size ranging from 31.1 to 45.6 µm long x 4 to 4.6 µm wide. Microconidia were zero to 1septate, ellipsoid to ovoid and varied in size from 9.5 to 16.8 µm long x 3 to 3.2 µm wide. Chlamydospores formed abundantly, in chains or clusters. This fungus was identified as F. armeniacum (Burgess et al. 1993). Identification was confirmed by sequencing three DNA regions including the internal spacer ribosomal DNA (ITS), elongation factor 1α and ß-tubulin genes (Lu et al. 2019). The three DNA regions (MN417271, MG457199, and MN427653) had 100% homology to the sequences of F. armeniacum (KJ737378, HM744664 and HQ141640) (Wang et al. 2015, Yli-Mattila et al. 2011). Pathogenicity tests were conducted on 1- to 2-year-old bare roots and 2-year-old whole plants. For root inoculation, 14 healthy roots were inoculated with two mycelial PDA plugs/root. After 3 to 10 days at 25°C, all the inoculated roots showed water-soaked and root rot symptoms while no lesions were observed in the control roots. For plant inoculation, eight seedlings planted in pots filled with sterilized soil were inoculated by pouring a conidial suspension of 1×105 conidia/ml at 30 ml/pot. Eight seedlings inoculated with sterilized water served as the controls. After 90 days, only 37.5% of the roots survived with typical root rot symptoms whereas the control plants remained symptomless. F. armeniacum was re-isolated from symptomatic roots but not from the control roots. Besides F. armeniacum, F. solani and F. oxysporum that have been reported to be associated with American ginseng root rot in China and Canada (Reeleder et al. 2002; Punja et al. 2008) were also obtained from the diseased root samples in this study. However, the development of root rot caused by F. armeniacum was much more rapid and its symptoms were more severe. Moreover, F. armeniacum could directly infect American ginseng with no wound requirement. F. armeniacum was previously reported on Glycine max (Leguminosae) (Ellis et al. 2012), Platycodon grandiflorus (Campanulaceae) (Wang et al. 2015) and natural grasses (Poaceae) (Nichea et al. 2015). This is the first report of F. armeniacum causing root rot on American ginseng in China. As this species is more virulent to American ginseng, more research is needed to work on this disease.

[Effects of nutrients deficiency on growth and saponin accumulation of American ginseng].

Mineral nutrient elements are the key factors to maintain the growth and quality of American ginseng. In order to understand the comprehensive effect of different nutrient elements deficiency on American ginseng, 2-year-old American ginsengs were cultivated by Hoagland solution(CK) or 10 different nutrients deficiency solution in sand culture. During the cultivation, the deficient symptom was observed. The plant height, leaf area, biomass, photosynthetic index, root activity, ginsenoside content were measured. The results showed that N, K or Fe deficiency could lead to leaves of American ginseng yellowing. Deficiency N, K, Ca, Mg and B were the main factors that decrease plant height and leaf area. The biomass of plant decreased significantly in all the nutrient deficient treatments(P<0.05)compared with control group, and N, K, Ca or Fe deficiency groups descended over 50%. In the absence of N, K and Fe elements, the P_n, G_s, C_i, T_r and chlorophyll of leaves were decreased mostly. The first three factors decreasing root activity were N, K and Ca deficiency. The effects of nutrient deficiency on saponins of American ginseng were different.Generally, N, P, B, Zn and Cu deficiency resulted the synthesis of saponins decreased significantly(P<0.05). This study contributed to clarify the demand characteristics of American ginseng for different nutrient elements,which is of great significance for the diagnose of nutrient deficiency, the rational fertilizer and the improvement of yield and quality of American ginseng.

Effects of maize rotation on the physicochemical properties and microbial communities of American ginseng cultivated soil.

The production of American ginseng (Panax quinquefolius L.) is severely limited by the replant disorders in China. Crop rotation with maize might reduce the replant problems, but little information is available on the effect of maize rotation on soil cultivated with ginseng. In this study, we analyzed nutrients, phenolic acids, and microbial communities in soils from the fields with continuous maize, mono-culture ginseng, and 1-, 3-, and 5-year maize rotation after ginseng. Pot experiments were also conducted to evaluate the performance of replanting ginseng in these soils. The results showed that Mn, Cu, and 5 phenolic acids in ginseng-cultivated soil were significantly decreased by maize rotation. A 5-year maize rotation significantly increased the relative abundance of beneficial soil bacteria, such as Arthrobacter, rather than decreasing the abundances of potential pathogenic genera. Clustering analysis revealed that the physicochemical properties and microbial communities of 3- and 5-year maize rotation soil were more similar to CM than to G soil. The biomass of replanted ginseng root was improved, and root disease was reduced over 3 years of maize rotation. Overall, the results showed that at least a 3-year maize rotation is needed to overcome the replant failure of American ginseng.

Modified Xiaoyaosan reverses aberrant brain regional homogeneity to exert antidepressive effects in mice.

The aim of this study is to explore the macroscale neural mechanisms of the antidepressant effects of Xiaoyaosan, a traditional Chinese herbal formula. We analyzed blood oxygen level-dependent (BOLD) functional magnetic resonance imaging signals. To further minimize the hemodynamic variations of BOLD signals and analyze the intra-region neural activity or temporal coherence, we employed the newly developed regional homogeneity (ReHo) approach to determine aberrant functional connectivity using the chronic unpredictable mild stress (CUMS) mouse model of depression and to also explore the brain-region rescue effect of modified Xiaoyaosan (MXYS) in such mice. We found the aberrant ReHo in CUMS mice replicated previous discoveries in patients with depression. Intriguingly, MXYS only normalized several limbic regions, which suggests the essential roles of these regions in mediating the antidepressant effects of MXYS. Our results provide a reliable framework for the use of ReHo analysis with animal models of depression and further suggest a new perspective to elucidate the antidepressant effects of MXYS.