Generalist taxa shape fungal community structure in cropping ecosystems

Fungi regulate nutrient cycling, decomposition, symbiosis, and pathogenicity in cropland soils. However, the relative importance of generalist and specialist taxa in structuring soil fungal community remains largely unresolved. We hypothesized that generalist fungi, which are adaptable to various environmental conditions, could potentially dominate the community and become the basis for fungal coexisting networks in cropping systems. In this study, we identified the generalist and habitat specialist fungi in cropland soils across a 2,200 kms environmental gradient, including three bioclimatic regions (subtropical, warm temperate, and temperate). A few fungal taxa in our database were classified as generalist taxa (~1%). These generalists accounted for >35% of the relative abundance of all fungal populations, and most of them are Ascomycota and potentially pathotrophic. Compared to the specialist taxa (5–17% of all phylotypes in three regions), generalists had a higher degree of connectivity and were often identified as hub within the network. Structural equation modeling provided further evidence that after accounting for spatial and climatic/ edaphic factors, generalists had larger contributions to the fungal coexistence pattern than habitat specialists. Taken together, our study provided evidence that generalist taxa are crucial components for fungal community structure. The knowledge of generalists can provide important implication for understanding the ecological preference of fungal groups in cropland systems

Health impacts of parental migration on left-behind children and adolescents: a systematic review and meta-analysis.

BACKGROUND: Globally, a growing number of children and adolescents are left behind when parents migrate. We investigated the effect of parental migration on the health of left behind-children and adolescents in low-income and middle-income countries (LMICs). METHODS: For this systematic review and meta-analysis we searched MEDLINE, Embase, CINAHL, the Cochrane Library, Web of Science, PsychINFO, Global Index Medicus, Scopus, and Popline from inception to April 27, 2017, without language restrictions, for observational studies investigating the effects of parental migration on nutrition, mental health, unintentional injuries, infectious disease, substance use, unprotected sex, early pregnancy, and abuse in left-behind children (aged 0-19 years) in LMICs. We excluded studies in which less than 50% of participants were aged 0-19 years, the mean or median age of participants was more than 19 years, fewer than 50% of parents had migrated for more than 6 months, or the mean or median duration of migration was less than 6 months. We screened studies using systematic review software and extracted summary estimates from published reports independently. The main outcomes were risk and prevalence of health outcomes, including nutrition (stunting, wasting, underweight, overweight and obesity, low birthweight, and anaemia), mental health (depressive disorder, anxiety disorder, conduct disorders, self-harm, and suicide), unintentional injuries, substance use, abuse, and infectious disease. We calculated pooled risk ratios (RRs) and standardised mean differences (SMDs) using random-effects models. This study is registered with PROSPERO, number CRD42017064871. FINDINGS: Our search identified 10 284 records, of which 111 studies were included for analysis, including a total of 264 967 children (n=106 167 left-behind children and adolescents; n=158 800 children and adolescents of non-migrant parents). 91 studies were done in China and focused on effects of internal labour migration. Compared with children of non-migrants, left-behind children had increased risk of depression and higher depression scores (RR 1·52 [95% CI 1·27-1·82]; SMD 0·16 [0·10-0·21]), anxiety (RR 1·85 [1·36-2·53]; SMD 0·18 [0·11-0·26]), suicidal ideation (RR 1·70 [1·28-2·26]), conduct disorder (SMD 0·16 [0·04-0·28]), substance use (RR 1·24 [1·00-1·52]), wasting (RR 1·13 [1·02-1·24]) and stunting (RR 1·12 [1·00-1·26]). No differences were identified between left-behind children and children of non-migrants for other nutrition outcomes, unintentional injury, abuse, or diarrhoea. No studies reported outcomes for other infectious diseases, self-harm, unprotected sex, or early pregnancy. Study quality varied across the included studies, with 43% of studies at high or unclear risk of bias across five or more domains. INTERPRETATION: Parental migration is detrimental to the health of left-behind children and adolescents, with no evidence of any benefit. Policy makers and health-care professionals need to take action to improve the health of these young people. FUNDING: Wellcome Trust

Sub-synchronous resonance mitigation by a STATCOM in doubly fed induction generator-based wind farm connected to a series-compensated transmission network

With the fast development of wind power generation, large-scale wind farms are connected to an electrical network which is series compensated to increase transmission capacity. However, a series-compensated power system may encounter with a sub-synchronous resonance (SSR) problem. Flexible AC transmission systems controllers are widely applied to mitigate SSR and improve the transient stability of the power system. A static synchronous compensator (STATCOM) with an SSR damping controller is proposed to mitigate the potential of SSR in a series-compensated doubly fed induction generator-based wind farm. The local signal is used as the input of the damping controller, which is feasible to be implemented in a practical project. Taking account of different series compensation levels and operating conditions, extensive transient simulations have been carried out using power systems computer aided design/electromagnetic transients including DC (PSCAD/EMTDC) to demonstrate the capability of STATCOM in damping SSR. It is shown that the SSR is successfully alleviated by STATCOM, which also verifies the effectiveness of the proposed STATCOM controller in improving the stability of the transmission system

Molecular cloning and characterization of ClZE, a zeaxanthin epoxidase gene in watermelon (Citrullus lanatus)

In this study, a watermelon (Citrullus lanatus) zeaxanthin epoxidase gene, ClZE, was isolated by reverse transcription-polymerase chain reaction (PCR) together with RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE). The full cDNA sequence of ClZE is 2535 bp in length containing a 1998 bp open reading frame (ORF) that encodes 665 amino acids. ClZE was shown to share high homology with the putative ZE genes in other plant species. Prediction analysis revealed that ClZE bears two large conservative domains, including Pyr_redox and FHA (forkhead-associated domain). Phylogenetic analysis suggested that ClZE shares high similarity (94.8%) with CsZE from Cucumis sativus, but is far from the ZE genes of other species. Prokaryotic expression indicated that ClZE possessed the apparent molecular mass consistent with its calculated molecular mass of 73.1 KDa. Based on quantitative real-time PCR (qRT-PCR), ClZE was shown to be down-regulated under chilling–low irradiance stress in watermelon leaves. Transgenic Arabidopsis lines harbouring ClZE were generated to test the gene function in mediating plant response to chilling stress. The results indicated that the transgenic lines exhibited decreased non-photochemical quenching (NPQ) and maximum quantum efficiency of photosystem II (PSII) photochemistry (Fv/Fm), increased activities of peroxidase (POD), superoxide dismutase (SOD) and elevated content of malondialdehyde (MDA) relative to the wild type (WT) under chilling–low irradiance stress. In addition, overexpression of ClZE resulted in impaired xanthophyll cycle and aggravated PSII photoinhibition under chilling–low irradiance. All the results together suggested that ClZE plays major roles in regulating the photoinhibition behaviour

Mitogenome of a cryptic species within <i>Uropsilus</i> and divergence time estimation

<p><i>Uropsilus</i> sp. 4 is a new cryptic species, collected in Changyang county, Hubei province, China. In this study, the whole mitochondrial genome of <i>Uropsilus</i> sp. 4 was first determined and characterized. The genome is 16,542 bp in length, containing 13 protein coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a putative control region. Base on NJ, ML, and BI methods, we obtained the same topologies. <i>U.</i> sp. 4 clustered with <i>U. gracilis</i> and the divergence time was 1.78 Ma (95% CI 1.24–2.32 Ma), in concordance with the third period of last orogenic push of the Qinghai-Tibetan Plateau, might contribute to the speciation of <i>U</i>. sp. 4.</p

SaaS sRNA promotes Salmonella intestinal invasion via modulating MAPK inflammatory pathway

ABSTRACTSalmonella Enteritidis is a foodborne enteric pathogen that infects humans and animals, utilizing complex survival strategies. Bacterial small RNA (sRNA) plays an important role in these strategies. However, the virulence regulatory network of S. Enteritidis remains largely incomplete and knowledge of gut virulence mechanisms of sRNAs is limited. Here, we characterized the function of a previously identified Salmonella adhesive-associated sRNA (SaaS) in the intestinal pathogenesis of S. Enteritidis. We found that SaaS promoted bacterial colonization in both cecum and colon of a BALB/c mouse model; it was preferentially expressed in colon. Moreover, our results showed that SaaS enhanced damage to mucosal barrier by affecting expressions of antimicrobial products, decreasing the number of goblet cells, suppressing mucin gene expression, and eventually reducing thickness of mucus layer; it further breached below physical barrier by strengthening invasion into epithelial cells in Caco-2 cell model as well as decreasing tight junction expressions. High throughput 16S rRNA gene sequencing revealed that SaaS also altered gut homeostasis by depleting beneficial gut microbiota while increasing harmful ones. Furthermore, by employing ELISA and western blot analysis, we demonstrated that SaaS regulated intestinal inflammation through sequential activation P38-JNK-ERK MAPK signaling pathway, which enabled immune escape at primary infection stage but strengthened pathogenesis at later stage, respectively. These findings suggest that SaaS plays an essential role in the virulence of S. Enteritidis and reveals its biological role in intestinal pathogenesis

A review of the effect of exosomes from different cells on liver fibrosis

Hepatic fibrosis (HF) is a common pathological process caused by various acute and chronic liver injury factors, which is mainly characterized by inflammation and excessive accumulation of extracellular matrix (ECM) in the liver. A better understanding of the mechanisms leading to liver fibrosis helps develop better treatments. The exosome is a crucial vesicle secreted by almost all cells, containing nucleic acids, proteins, lipids, cytokines, and other bioactive components, which play an important role in the transmission of intercellular material and information. Recent studies have shown the relevance of exosomes in the pathogenesis of hepatic fibrosis, and exosomes dominate an essential role in hepatic fibrosis. In this review, we systematically analyze and summarize exosomes from diverse cell sources as potential promoters, inhibitors, and even treatments for hepatic fibrosis to provide a clinical reference for exosomes as the diagnostic target or therapeutic means of hepatic fibrosis

Human umbilical cord matrix-derived stem cells exert trophic effects on β-cell survival in diabetic rats and isolated islets

Human umbilical cord matrix-derived stem cells (uMSCs), owing to their cellular and procurement advantages compared with mesenchymal stem cells derived from other tissue sources, are in clinical trials to treat type 1 (T1D) and type 2 diabetes (T2D). However, the therapeutic basis remains to be fully understood. The immunomodulatory property of uMSCs could explain the use in treating T1D; however, the mere immune modulation might not be sufficient to support the use in T2D. We thus tested whether uMSCs could exert direct trophic effects on β-cells. Infusion of uMSCs into chemically induced diabetic rats prevented hyperglycemic progression with a parallel preservation of islet size and cellularity, demonstrating the protective effect of uMSCs on β-cells. Mechanistic analyses revealed that uMSCs engrafted long-term in the injured pancreas and the engraftment markedly activated the pancreatic PI3K pathway and its downstream anti-apoptotic machinery. The pro-survival pathway activation was associated with the expression and secretion of β-cell growth factors by uMSCs, among which insulin-like growth factor 1 (IGF1) was highly abundant. To establish the causal relationship between the uMSC-secreted factors and β-cell survival, isolated rat islets were co-cultured with uMSCs in the transwell system. Co-culturing improved the islet viability and insulin secretion. Furthermore, reduction of uMSC-secreted IGF1 via siRNA knockdown diminished the protective effects on islets in the co-culture. Thus, our data support a model whereby uMSCs exert trophic effects on islets by secreting β-cell growth factors such as IGF1. The study reveals a novel therapeutic role of uMSCs and suggests that multiple mechanisms are employed by uMSCs to treat diabetes