Biocontrol of Fusarium wilt disease in muskmelon with Bacillus subtilis Y-IVI

Muskmelon (Cucumis melo L.) wilt caused by Fusarium oxysporum f. sp. melonis leads to severe economic losses. A bio-organic fertilizer (BIO) fortified with an antagonistic strain of Bacillus subtilis Y-IVI was used to control this disease. Pot experiments were carried out to investigate the efficacy and to elucidate biocontrol mechanisms for the disease. BIO significantly reduced the disease incidence. Population of F. oxysporum in plant shoots of the BIO treatment were about 1000-fold lower than the control. Population of Y-IVI remained high in muskmelon rhizosphere of the BIO treatment during the experiment. Concentration of antifungal lipopeptides, iturin A, in the BIO treatment was significantly higher than other treatments. Ten days after transplantation, the salicylic acid content in BIO-treated plant leaves was significantly higher than control. In conclusion, BIO effectively controlled muskmelon wilt, possibly because the antagonistic microbes effectively colonize the plant rhizosphere and shoots to preclude pathogen invasion. Furthermore, Y-IVI produces antifungal lipopeptides in the rhizosphere.     

Apoptosis phenomenon in the schistosomulum and adult worm life cycle stages of Schistosoma japonicum

Apoptosis is an important aspect of a number of biological processes, from embryogenesis to the stress–injury response. It plays a central role in balancing cell proliferation and tissue remodeling activity in many organisms. In the present study, apoptosis in 14 days post infection schistosomula was evaluated using TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling) assays and DAPI staining. Additionally, flow cytometry using the Annexin V-FITC/propidium iodide (PI) (Annexin V/PI) assay confirmed the percentage of early apoptotic, late apoptotic, and necrotic cells in 14 and 23 days post infection worms. Conserved Domain Database (CDD) BLAST analysis and alignment analysis of known schistosome proteins demonstrated the feasibility of detecting the activity of caspase-3 and -7 using the caspase-3/7 Glo analysis assay. Analysis of caspase-3 and -7 activities in schistosome demonstrated that both caspases were active in each developmental stage of Schistosoma japonicum, but was highest in the 14 days post infection schistosomula. Additionally, the caspase peptide inhibitor (Z-VAD-FMK) inhibited the caspase-3/7 activity at all developmental stages examined. Therefore, we hypothesized that two main signaling pathways are involved in apoptosis in S. japonicum, the caspase cascade and the mitochondrial-initiated pathway. We have constructed a model of these two pathways, including how they may interact and their biological outcomes. qRT-PCR analyses of the gene expression profiles of apoptosis-related genes supported our hypothesis of the relationship between the apoptotic pathway and parasite development. The data presented here demonstrates that apoptosis is an important biological process for the survival and development of the schistosome, and identifies potential novel therapeutic targets.     

The New Perspectives on Genetic Studies of Type 2 Diabetes and Thyroid Diseases

Recently, genome-wide association studies (GWAS) have led to the discovery of hundreds of susceptibility loci that are associated with complex metabolic diseases, such as type 2 diabetes and hyperthyroidism. The majority of the susceptibility loci are common across different races or populations; while some of them show ethnicity-specific distribution. Though the abundant novel susceptibility loci identified by GWAS have provided insight into biology through the discovery of new genes or pathways that were previously not known, most of them are in introns and the associated variants cumulatively explain only a small fraction of total heritability. Here we reviewed the genetic studies on the metabolic disorders, mainly type 2 diabetes and hyperthyroidism, including candidate genes-based findings and more recently the GWAS discovery; we also included the clinical relevance of these novel loci and the gene-environmental interactions. Finally, we discussed the future direction about the genetic study on the exploring of the pathogenesis of the metabolic diseases.     

Molecular analysis of fungal diversity associated with three bryophyte species in the Fildes Region, King George Island, maritime Antarctica

The fungal communities associated with three bryophytes species (the liverwort Barbilophozia hatcheri, the mosses Chorisodontium aciphyllum and Sanionia uncinata) in the Fildes Region, King George Island, maritime Antarctica, were studied using clone library analysis. Fungal communities showed low diversity; the 680 clones belonged to 93 OTUs. Of these, 78 belonged to the phylum Ascomycota, 13 to the phylum Basidiomycota, 1 to the phylum Zygomycota, and 1 to an unknown phylum. Among the OTUs, the most common orders in the Ascomycota were Helotiales (42 OTUs) and Chaetothyriales (14 OTUs) and the most common orders in the Basidiomycota were Sebacinales (3 OTUs) and Platygloeales (3 OTUs). Most OTUs clustered within clades that contained phylotypes identified from samples in Antarctic or Arctic ecosystems or from bryophytes in other ecosystems. In addition, we found that host-related factor may shape the fungal communities associated with bryophytes in this region. This is the first systematic study of the fungal community in Antarctic bryophytes to be performed using culture-independent method and the results may improve understanding of the endophytic fungal evolution and ecology in the Antarctic ecosystem.     

Phylogenetically Diverse Denitrifying and Ammonia-Oxidizing Bacteria in Corals Alcyonium gracillimum and Tubastraea coccinea

To date, the association of coral–bacteria and the ecological roles of bacterial symbionts in corals remain largely unknown. In particular, little is known about the community components of bacterial symbionts of corals involved in the process of denitrification and ammonia oxidation. In this study, the nitrite reductase (nirS and nirK) and ammonia monooxygenase subunit A (amoA) genes were used as functional markers. Diverse bacteria with the potential to be active as denitrifiers and ammonia-oxidizing bacteria (AOB) were found in two East China Sea corals: stony coral Alcyonium gracillimum and soft coral Tubastraea coccinea. The 16S rRNA gene library analysis demonstrated different communities of bacterial symbionts in these two corals of the same location. Nitrite reductase nirK gene was found only in T. coccinea, while both nirK and nirS genes were detected in A. gracillimum, which might be the result of the presence of different bacterial symbionts in these two corals. AOB rather than ammonia-oxidizing archaea were detected in both corals, suggesting that AOB might play an important role in the ammonia oxidation process of the corals. This study indicates that the coral bacterial symbionts with the potential for nitrite reduction and ammonia oxidation might have multiple ecological roles in the coral holobiont, which promotes our understanding of bacteria-mediated nitrogen cycling in corals. To our knowledge, this study is the first assessment of the community structure and phylogenetic diversity of denitrifying bacteria and AOB in corals based on nirK, nirS, and amoA gene library analysis.     

Effects of the Conversion of Native Vegetation to Farmlands on Soil Microarthropod Biodiversity and Ecosystem Functioning in a Desert Oasis

Increased demand for food due to the rapidly growing human population has led to extensive conversion of native steppes at the margins of oases in arid lands of northwest China into intensively managed farmlands. However, the consequences of this land-use change for soil microarthropod biodiversity and ecosystem functioning remain unknown. Here we assessed how conversion of a native steppe to irrigated farmlands of different ages affects the abundance and composition of soil microarthropods and how changes in soil microarthropod biodiversity could scale up to influence soil carbon and nitrogen stocks. We sampled microarthropod communities over two growing seasons from native steppes and cultivated soils of a 27-year-old irrigated farmland and a 90-year-old irrigated farmland, both of which were converted from the native steppe. Topsoil properties and bulk and labile pools of carbon and nitrogen, including soil organic carbon, dissolved organic carbon (DOC), microbial biomass carbon (MBC), total nitrogen (TN), inorganic nitrogen (IN), and microbial biomass nitrogen (MBN), were also measured. The conversion of native steppe to either of the two farmlands significantly increased the abundance and taxa richness of three taxonomic groups (mites, collembolans, and others) and four trophic groups (herbivores, predators, detritivores, and fungivores); this effect was greater in the 90-year-old farmland for the abundance of all taxonomic and trophic groups except for herbivores and was similar between the two farmlands for the richness of all taxonomic and trophic groups. Taxonomic and trophic composition of the microarthropod community showed strong shifts in response to conversion of native steppe to either of the two farmlands. Compositional changes were largely mediated by changes in soil environments. Changes in soil carbon and nitrogen stocks due to conversion of native steppe to farmlands followed similar patterns to soil microarthropod biodiversity, but the greater storage of DOC, MBC, TN, IN, and MBN occurred in the 90-year-old farmland. Our results suggest that soil microarthropod communities are affected positively by native steppe conversion to farmland and farmland age, and that increased microarthropod biodiversity significantly improved the ability of soils to retain carbon and nitrogen.     

Community mean traits as additional indicators to monitor effects of land-use intensity on grassland plant diversity

Semi-natural grasslands, biodiversity hotspots in Central-Europe, suffer from the cessation of traditional land-use. Amount and intensity of these changes challenge current monitoring frameworks typically based on classic indicators such as selected target species or diversity indices. Indicators based on plant functional traits provide an interesting extension since they reflect ecological strategies at individual and ecological processes at community levels. They typically show convergent responses to gradients of land-use intensity over scales and regions, are more directly related to environmental drivers than diversity components themselves and enable detecting directional changes in whole community dynamics. However, probably due to their labor- and cost intensive assessment in the field, they have been rarely applied as indicators so far.Here we suggest overcoming these limitations by calculating indicators with plant traits derived from online accessible databases. Aiming to provide a minimal trait set to monitor effects of land-use intensification on plant diversity we investigated relationships between 12 community mean traits, 2 diversity indices and 6 predictors of land-use intensity within grassland communities of 3 different regions in Germany (part of the German ‘Biodiversity Exploratory’ research network). By standardization of traits and diversity measures, use of null models and linear mixed models we confirmed (i) strong links between functional community composition and plant diversity, (ii) that traits are closely related to land-use intensity, and (iii) that functional indicators are equally, or even more sensitive to land-use intensity than traditional diversity indices. The deduced trait set consisted of 5 traits, i.e., specific leaf area (SLA), leaf dry matter content (LDMC), seed release height, leaf distribution, and onset of flowering. These database derived traits enable the early detection of changes in community structure indicative for future diversity loss. As an addition to current monitoring measures they allow to better link environmental drivers to processes controlling community dynamics.     

Interleukin-8 Regulates Endothelial Permeability by Down-regulation of Tight Junction but not Dependent on Integrins Induced Focal Adhesions

Interleukin-8 (IL-8) is a common inflammatory factor, which involves in various non-specific pathological processes of inflammation. It has been found that increased endothelial permeability accompanied with high expression of IL-8 at site of injured endothelium and atherosclerotic plaque at early stages, suggesting that IL-8 participated in regulating endothelial permeability in the developing processes of vascular disease. The purpose of this study is to investigate the regulation effects of IL-8 on the vascular endothelial permeability, and the mRNA and protein expression of tight junction components (i.e., ZO-1, Claudin-5 and Occludin). Endothelial cells were stimulated by IL-8 with the dose of 50, 100 and 200 ng/mL, and duration of 2, 4, 6, 8h, respectively. The mRNA and protein expression level of tight junction components with IL-8 under different concentration and duration was examined by RT-PCR and Western blot, respectively. Meanwhile, the integrins induced focal adhesions event with IL-8 stimulation was also investigated. The results showed that IL-8 regulated the permeability of endothelium by down-regulation of tight junction in a dose- and time-dependence manner, but was not by integrins induced focal adhesions. This finding reveals the molecular mechanism in the increase of endothelial cell permeability induced by IL-8, which is expected to provide a new idea as a therapeutic target in vascular diseases.     

Molecular Characterization and Alternative Splicing of a Sodium Channel and DSC1 Ortholog Genes in Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae)

Alternative splicing greatly contributes to the structural and functional diversity of voltage-gated sodium channels (VGSCs) by generating various isoforms with unique functional and pharmacological properties. Here, we identified a new optional exon 23 located in the linker between domains II and III, and four mutually exclusive exons (exons 27A, 27B, 27C, and 27D) in domains IIIS3 and IIIS4 of the sodium channel of Liposcelis bostrychophila (termed as LbVGSC). This suggested that more alternative splicing phenomena remained to be discovered in VGSCs. Inclusion of exon 27C might lead to generation of non-functional isoforms. Meanwhile, identification of three alternative exons (exons 11, 13A, and 13B), which were located in the linker between domains II and III, indicated that abundant splicing events occurred in the DSC1 ortholog channel of L. bostrychophila (termed as LbSC1). Exons 13A and 13B were generated by intron retention, and the presence of exon 13B relied on the inclusion of exon 13A. Exon 13B was specifically expressed in the embryonic stage and contained an in-frame stop codon, inclusion of which led to generation of truncated proteins with only the first two domains. Additionally, several co-occurring RNA editing events were identified in LbSC1. Furthermore, remarkable similarity between the structure and expression patterns of LbVGSC and LbSC1 were discovered, and a closer evolutionary relationship between VGSCs and DSC1 orthologs was verified. Taken together, the data provided abundant molecular information on VGSC and DSC1 orthologs in L. bostrychophila, a representative Psocoptera storage pest, and insights into the alternative splicing of these two channels.