Search results for "Proteobacteria"

The swinholide biosynthesis gene cluster from a terrestrial cyanobacterium, Nostoc sp. strain UHCC 0450

2017

ABSTRACT Swinholides are 42-carbon ring polyketides with a 2-fold axis of symmetry. They are potent cytotoxins that disrupt the actin cytoskeleton. Swinholides were discovered from the marine sponge Theonella sp. and were long suspected to be produced by symbiotic bacteria. Misakinolide, a structural variant of swinholide, was recently demonstrated to be the product of a symbiotic heterotrophic proteobacterium. Here, we report the production of swinholide A by an axenic strain of the terrestrial cyanobacterium Nostoc sp. strain UHCC 0450. We located the 85-kb trans -AT polyketide synthase (PKS) swinholide biosynthesis gene cluster from a draft genome of Nostoc sp. UHCC 0450. The swinholide …

Prokaryotic assemblages within permafrost active layer at Edmonson Point (Northern Victoria Land, Antarctica)

2018

This study was aimed at gaining insights on the prokaryotic community (in terms of both taxonomic composition and activities) inhabiting the active layer at Edmonson Point, an ice-free area on the eastern slope at the foot of Mount Melbourne (Northern Victoria Land, Antarctica). Samples were collected during the thawing period, when microbial physiological activities are restored to utilize previously frozen organic substrates. Despite the very small cell sizes (600 daltons) substrates, as indicated also by the obtained rates of enzymatic hydrolytic activities over proteolytic, glycolitic and phosphoric compounds. Taxonomical composition showed that Proteobacteria, Actinobacteria and Firmic…

Human Breast Milk NMR Metabolomic Profile across Specific Geographical Locations and Its Association with the Milk Microbiota

2018

The composition of human breast milk is highly variable, and it can be influenced by genetics, diet, lifestyle, and other environmental factors. This study aimed to investigate the impact of geographical location and mode of delivery on the nuclear magnetic resonance spectroscopy (NMR) metabolic profile of breast milk and its relationship with the milk microbiome. Human milk metabolic and microbiota profiles were determined using NMR and 16S rRNA gene sequencing, respectively, in 79 healthy women from Finland, Spain, South Africa, and China. Up to 68 metabolites, including amino acids, oligosaccharides, and fatty acid-associated metabolites, were identified in the milk NMR spectra. The meta…

Native arbuscular mycorrhizal symbiosis alters foliar bacterial community composition.

2017

The effects of arbuscular mycorrhizal (AM) fungi on plant-associated microbes are poorly known. We tested the hypothesis that colonization by an AM fungus affects microbial species richness and microbial community composition of host plant tissues. We grew the grass, Deschampsia flexuosa in a greenhouse with or without the native AM fungus, Claroideoglomus etunicatum. We divided clonally produced tillers into two parts: one inoculated with AM fungus spores and one without AM fungus inoculation (non-mycorrhizal, NM). We characterized bacterial (16S rRNA gene) and fungal communities (internal transcribed spacer region) in surface-sterilized leaf and root plant compartments. AM fungus inoculat…

Antibacterial activity of the sponge Suberites domuncula and its primmorphs: potential basis for epibacterial chemical defense

2003

The epibacterial chemical defense of the marine sponge Suberites domuncula was explored by screening sponge extract, sponge primmorph (3-D aggregates containing proliferating cells) extract and sponge-associated as well as primmorph-associated bacteria for antibacterial activ- ity. 16S rDNA sequencing revealed that the antimicrobially active bacteria belonged to the α - and γ- subdivisions of Proteobacteria (α -Proteobacterium MBIC 3368, Idiomarina sp. and Pseudomonas sp., respectively). Moreover, a recombinant perforin-like protein was cloned from S. domuncula that dis- played strong antibacterial activity. Based on these observations, it is proposed that the sponge may be provided with a …

2020

The rapid developments in the next-generation sequencing methods in the recent years have provided a wealth of information on the community structures and functions of endophytic bacteria. However, the assembly processes of these communities in different plant tissues are still currently poorly understood, especially in wild plants in natural settings. The aim of this study was to compare the composition of endophytic bacterial communities in leaves and roots of arcto-alpine pioneer plant Oxyria digyna, and investigate, how plant tissue (leaf or root) or plant origin affect the community assembly. To address this, we planted micropropagated O. digyna plants with low bacterial load (bait pla…

Fire and phylogenetic structure of soil microbial communities in Mediterranean ecosystems

2017

Tesis llevada a cabo para conseguir el grado de Doctor por la Universidad de Valencia.--2018-02-21.--Sobresaliente Cum laudem

Complete genome sequence of the strain Defluviitoga tunisiensis L3, isolated from a thermophilic, production-scale biogas plant.

2015

An anaerobic, thermophilic bacterium belonging to the phylum Thermotogae was isolated from a rural, thermophilic biogas plant (54 degrees C) producing methane-rich biogas from maize silage, barley, cattle and pig manure. Here we report the first complete genome sequence of the Defluviitoga tunisiensis strain L3, an isolate from the family Thermotogaceae. The strain L3 encodes several genes predicted to be involved in utilization of a large diversity of complex carbohydrates including cellobiose and xylan for the production of acetate, hydrogen (H-2) and carbon dioxide (CO2). The genome sequence of D. tunisiensis L3 provides the basis for biotechnological exploitation of genetic determinants…

Diet shapes the gut microbiota of the omnivorous cockroach Blattella germanica

2015

The gut microbiota of insects contributes positively to the physiology of its host mainly by participating in food digestion, protecting against pathogens, or provisioning vitamins or amino acids, but the dynamics of this complex ecosystem is not well understood so far. In this study, we have characterized the gut microbiota of the omnivorous cockroach Blattella germanica by pyrosequencing the hypervariable regions V1-V3 of the 16S rRNA gene of the whole bacterial community. Three diets differing in the protein content (0, 24 and 50%) were tested at two time points in lab-reared individuals. In addition, the gut microbiota of wild adult cockroaches was also analyzed. In contrast to the high…

Assessing genetic structure and diversity of airborne bacterial communities by DNA fingerprinting and 16S rDNA clone library

2005

Abstract The density, genetic structure and diversity of airborne bacterial communities were assessed in the outdoor atmosphere. Two air samples were collected on the same location (north of France) at two dates (March 2003 (sample1) and May 2003 (sample 2)). Molecular culture-independent methods were used to characterise airborne bacterial communities regardless of the cell culturability. The automated-ribosomal intergenic spacer analysis (A-RISA) was performed to characterise the community structure in each sample. For both sampling dates, complex A-RISA patterns were observed suggesting a highly diverse community structure, comparable to those found in soil, water or sediment environment…