70 research outputs found
Parameters Governing the Community Structure and Element Turnover in Kermadec Volcanic Ash and Hydrothermal Fluids as Monitored by Inorganic Electron Donor Consumption, Autotrophic CO2 Fixation and 16S Tags of the Transcriptome in Incubation Experiments
The microbial community composition and its functionality was assessed for hydrothermal fluids and volcanic ash sediments from Haungaroa and hydrothermal fluids from the Brothers volcano in the Kermadec island arc (New Zealand). The Haungaroa volcanic ash sediments were dominated by epsilonproteobacterial Sulfurovum sp. Ratios of electron donor consumption to CO2 fixation from respective sediment incubations indicated that sulfide oxidation appeared to fuel autotrophic CO2 fixation, coinciding with thermodynamic estimates predicting sulfide oxidation as the major energy source in the environment. Transcript analyses with the sulfide-supplemented sediment slurries demonstrated that Sulfurovum prevailed in the experiments as well. Hence, our sediment incubations appeared to simulate environmental conditions well suggesting that sulfide oxidation catalyzed by Sulfurovum members drive biomass synthesis in the volcanic ash sediments. For the Haungaroa fluids no inorganic electron donor and responsible microorganisms could be identified that clearly stimulated autotrophic CO2 fixation. In the Brothers hydrothermal fluids Sulfurimonas (49%) and Hydrogenovibrio/Thiomicrospira (15%) species prevailed. Respective fluid incubations exhibited highest autotrophic CO2 fixation if supplemented with iron(II) or hydrogen. Likewise catabolic energy calculations predicted primarily iron(II) but also hydrogen oxidation as major energy sources in the natural fluids. According to transcript analyses with material from the incubation experiments Thiomicrospira/Hydrogenovibrio species dominated, outcompeting Sulfurimonas. Given that experimental conditions likely only simulated environmental conditions that cause Thiomicrospira/Hydrogenovibrio but not Sulfurimonas to thrive, it remains unclear which environmental parameters determine Sulfurimonas’ dominance in the Brothers natural hydrothermal fluids
The basic helix-loop-helix transcription factor TCF4 impacts brain architecture as well as neuronal morphology and differentiation
Germline mutations in the basic helix-loop-helix transcription factor 4 (TCF4) cause the Pitt–Hopkins syndrome (PTHS), a developmental disorder with severe intellectual disability. Here, we report findings from a new mouse model with a central nervous system-specific truncation of Tcf4 leading to severe phenotypic abnormalities. Furthermore, it allows the study of a complete TCF4 knockout in adult mice, circumventing early postnatal lethality of previously published mouse models. Our data suggest that a TCF4 truncation results in an impaired hippocampal architecture affecting both the dentate gyrus as well as the cornu ammonis. In the cerebral cortex, loss of TCF4 generates a severe differentiation delay of neural precursors. Furthermore, neuronal morphology was critically affected with shortened apical dendrites and significantly increased branching of dendrites. Our data provide novel information about the role of Tcf4 in brain development and may help to understand the mechanisms leading to intellectual deficits observed in patients suffering from PTHS
Deep (Meta)genomics and (Meta)transcriptome Analyses of Fungal and Bacteria Consortia From Aircraft Tanks and Kerosene Identify Key Genes in Fuel and Tank Corrosion
Microbial contamination of fuels, associated with a wide variety of bacteria and fungi, leads to decreased product quality and can compromise equipment performance by biofouling or microbiologically influenced corrosion. Detection and quantification of microorganisms are critical in monitoring fuel systems for an early detection of microbial contaminations. To address these challenges, we have analyzed six metagenomes, one transcriptome, and more than 1,200 fluid and swab samples taken from fuel tanks or kerosene. Our deep metagenome sequencing and binning approaches in combination with RNA-seq data and qPCR methods implied a metabolic symbiosis between fungi and bacteria. The most abundant bacteria were affiliated with α-, β-, and γ-Proteobacteria and the filamentous fungi Amorphotheca. We identified a high number of genes, which are related to kerosene degradation and biofilm formation. Surprisingly, a large number of genes coded enzymes involved in polymer degradation and potential bio-corrosion processes. Thereby, the transcriptionally most active microorganisms were affiliated with the genera Methylobacteria, Pseudomonas, Kocuria, Amorpotheka, Aspergillus, Fusarium, and Penicillium. Many not yet cultured bacteria and fungi appeared to contribute to the biofilm transcriptional activities. The largest numbers of transcripts were observed for dehydrogenase, oxygenase, and exopolysaccharide production, attachment and pili/flagella-associated proteins, efflux pumps, and secretion systems as well as lipase and esterase activity
RNF40 regulates gene expression in an epigenetic context-dependent manner
Background Monoubiquitination of H2B (H2Bub1) is a largely enigmatic histone modification that has been linked to transcriptional elongation. Because of this association, it has been commonly assumed that H2Bub1 is an exclusively positively acting histone modification and that increased H2Bub1 occupancy correlates with increased gene expression. In contrast, depletion of the H2B ubiquitin ligases RNF20 or RNF40 alters the expression of only a subset of genes. Results Using conditional Rnf40 knockout mouse embryo fibroblasts, we show that genes occupied by low to moderate amounts of H2Bub1 are selectively regulated in response to Rnf40 deletion, whereas genes marked by high levels of H2Bub1 are mostly unaffected by Rnf40 loss. Furthermore, we find that decreased expression of RNF40-dependent genes is highly associated with widespread narrowing of H3K4me3 peaks. H2Bub1 promotes the broadening of H3K4me3 to increase transcriptional elongation, which together lead to increased tissue-specific gene transcription. Notably, genes upregulated following Rnf40 deletion, including Foxl2, are enriched for H3K27me3, which is decreased following Rnf40 deletion due to decreased expression of the Ezh2 gene. As a consequence, increased expression of some RNF40-“suppressed” genes is associated with enhancer activation via FOXL2. Conclusion Together these findings reveal the complexity and context-dependency whereby one histone modification can have divergent effects on gene transcription. Furthermore, we show that these effects are dependent upon the activity of other epigenetic regulatory proteins and histone modifications
Microbial ecosystem assessment and hydrogen oxidation potential of newly discovered vent systems from the Central and South-East Indian Ridge
In order to expand the knowledge of microbial ecosystems from deep-sea hydrothermal vent systems located on the Central and South-East Indian Ridge, we sampled hydrothermal fluids, massive sulfides, ambient water and sediments of six distinct vent fields. Most of these vent sites were only recently discovered in the course of the German exploration program for massive sulfide deposits and no previous studies of the respective microbial communities exist. Apart from typically vent-associated chemosynthetic members of the orders Campylobacterales, Mariprofundales, and Thiomicrospirales, high numbers of uncultured and unspecified Bacteria were identified via 16S rRNA gene analyses in hydrothermal fluid and massive sulfide samples. The sampled sediments however, were characterized by an overall lack of chemosynthetic Bacteria and the presence of high proportions of low abundant bacterial groups. The archaeal communities were generally less diverse and mostly dominated by members of Nitrosopumilales and Woesearchaeales, partly exhibiting high proportions of unassigned Archaea. Correlations with environmental parameters were primarily observed for sediment communities and for microbial species (associated with the nitrogen cycle) in samples from a recently identified vent field, which was geochemically distinct from all other sampled sites. Enrichment cultures of diffuse fluids demonstrated a great potential for hydrogen oxidation coupled to the reduction of various electron-acceptors with high abundances of Hydrogenovibrio and Sulfurimonas species. Overall, given the large number of currently uncultured and unspecified microorganisms identified in the vent communities, their respective metabolic traits, ecosystem functions and mediated biogeochemical processes have still to be resolved for estimating consequences of potential environmental disturbances by future mining activities
Pengembangan Kurikulum Pendidikan Lingkungan di Kota Tangerang Selatan: Bagaimana Mengintegrasikan Deklarasi Tbilisi dalam Kurikulum
This study aims to develop environmental education curriculum based on Tbilisi Declaration. There were five environmental education goals of Tbilisi Declaration namely knowledge, awareness, attitudes, skills, and participation. Curriculum was developed for supporting education policy in South Tangerang, Banten Province, Indonesia. Letter of Education Division South Tangerang City nomor 800/KEP 1222-dikdas/2014 stated environmental education as local curriculum in South Tangerang Elementary School. Curriculum was developed by developmental research. There was four steps to develop curriculum, every steps had three activities, i.e. making, reviewing, and fixing. This study result some standard and basic competences. Research developed environmental education was integrated with thematic subject matter in 1st and 2nd grade, but as monolithic subject matter in 3rd – 6rd grade. Using exiting competence standard from 2014 curriculum and format standard competence 2006 made this curriculum have flexibility to implement for the school that used 2006 or 2013 curriculum
Atypical teratoid/rhabdoid tumors (ATRTs) with SMARCA4 mutation are molecularly distinct from SMARCB1-deficient cases
Atypical teratoid/rhabdoid tumors (ATRTs) are very aggressive childhood malignancies of the central nervous system. The underlying genetic cause are inactivating bi-allelic mutations in SMARCB1 or (rarely) in SMARCA4. ATRT-SMARCA4 have been associated with a higher frequency of germline mutations, younger age, and an inferior prognosis in comparison to SMARCB1 mutated cases. Based on their DNA methylation profiles and transcriptomics, SMARCB1 mutated ATRTs have been divided into three distinct molecular subgroups: ATRT-TYR, ATRT-SHH, and ATRT-MYC. These subgroups differ in terms of age at diagnosis, tumor location, type of SMARCB1 alterations, and overall survival. ATRT-SMARCA4 are, however, less well understood, and it remains unknown, whether they belong to one of the described ATRT subgroups. Here, we examined 14 ATRT-SMARCA4 by global DNA methylation analyses. We show that they form a separate group segregating from SMARCB1 mutated ATRTs and from other SMARCA4-deficient tumors like small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) or SMARCA4 mutated extra-cranial malignant rhabdoid tumors. In contrast, medulloblastoma (MB) samples with heterozygous SMARCA4 mutations do not group separately, but with established MB subgroups. RNA sequencing of ATRT-SMARCA4 confirmed the clustering results based on DNA methylation profiling and displayed an absence of typical signature genes upregulated in SMARCB1 deleted ATRT. In summary, our results suggest that, in line with previous clinical observations, ATRT-SMARCA4 should be regarded as a distinct molecular subgroup
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Expression of a Structural Protein of the Mycovirus FgV-ch9 Negatively Affects the Transcript Level of a Novel Symptom Alleviation Factor and Causes Virus Infection-Like Symptoms in Fusarium graminearum
Infections of fungi by mycoviruses are often symptomless but sometimes also fatal, as they perturb sporulation, growth, and, if applicable, virulence of the fungal host. Hypovirulence-inducing mycoviruses, therefore, represent a powerful means to defeat fungal epidemics on crop plants. Infection with Fusarium graminearum virus China 9 (FgV-ch9), a double-stranded RNA (dsRNA) chrysovirus- like mycovirus, debilitates Fusarium graminearum, the causal agent of fusarium head blight. In search for potential symptom alleviation or aggravation factors in F. graminearum, we consecutively infected a custom-made F. graminearum mutant collection with FgV-ch9 and found a mutant with constantly elevated expression of a gene coding for a putative mRNA-binding protein that did not show any disease symptoms despite harboring large amounts of virus. Deletion of this gene, named virus response 1 (vr1), resulted in phenotypes identical to those observed in the virus-infected wild type with respect to growth, reproduction, and virulence. Similarly, the viral structural protein coded on segment 3 (P3) caused virus infection-like symptoms when expressed in the wild type but not in the vr1 overexpression mutant. Gene expression analysis revealed a drastic downregulation of vr1 in the presence of virus and in mutants expressing P3. We conclude that symptom development and severity correlate with gene expression levels of vr1. This was confirmed by comparative transcriptome analysis, showing a large transcriptional overlap between the virus-infected wild type, the vr1 deletion mutant, and the P3-expressing mutant. Hence, vr1 represents a fundamental host factor for the expression of virus-related symptoms and helps us understand the underlying mechanism of hypovirulence.
IMPORTANCE Virus infections of phytopathogenic fungi occasionally impair growth, reproduction, and virulence, a phenomenon referred to as hypovirulence. Hypovirulence-inducing mycoviruses, therefore, represent a powerful means to defeat fungal epidemics on crop plants. However, the poor understanding of the molecular basis of hypovirulence induction limits their application. Using the devastating fungal pathogen on cereal crops, Fusarium graminearum, we identified an mRNA binding protein (named virus response 1, vr1) which is involved in symptom expression. Downregulation of vr1 in the virus-infected fungus and vr1 deletion evoke virus infection-like symptoms, while constitutive expression overrules the cytopathic effects of the virus infection. Intriguingly, the presence of a specific viral structural protein is sufficient to trigger the fungal response, i.e., vr1 downregulation, and symptom development similar to virus infection. The advancements in understanding fungal infection and response may aid biological pest control approaches using mycoviruses or viral proteins to prevent future Fusarium epidemics
Next-generation sequencing of peripheral B-lineage cells pinpoints the circulating clonotypic cell pool in multiple myeloma
Key Points
Clonotypic B cells, long suspected to represent circulating stem-like cells, are consistently absent in the blood of myeloma patients. Malignant plasma cells frequently circulate in the peripheral blood, show evidence for clonal evolution, and may spread the disease.</jats:p
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