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Microbial Ecology Jan 2024Epiphytic bacteria constitute a vital component of aquatic ecosystems, pivotal in regulating elemental cycling. Despite their significance, the diversity and functions...
Epiphytic bacteria constitute a vital component of aquatic ecosystems, pivotal in regulating elemental cycling. Despite their significance, the diversity and functions of epiphytic bacterial communities adhering to various submerged macrophytes remain largely unexplored. In this study, we employed a metagenomic approach to investigate the diversity and function of epiphytic bacterial communities associated with six submerged macrophytes: Ceratophyllum demersum, Hydrilla verticillata, Myriophyllum verticillatum, Potamogeton lucens, Stuckenia pectinata, and Najas marina. The results revealed that the predominant epiphytic bacterial species for each plant type included Pseudomonas spp., Microbacterium spp., and Stenotrophomonas rhizophila. Multiple comparisons and linear discriminant analysis effect size indicated a significant divergence in the community composition of epiphytic bacteria among the six submerged macrophytes, with 0.3-1% of species uniquely identified. Epiphytic bacterial richness associated with S. pectinata significantly differed from that of both C. demersum and H. verticillata, although no significant differences were observed in diversity and evenness. Functionally, notable variations were observed in the relative abundances of genes associated with carbon, nitrogen, and phosphorus cycling within epiphytic bacterial communities on the submerged macrophyte hosts. Among these communities, H. verticillata exhibited enrichment in genes related to the 3-hydroxypropionate bicycle and nitrogen assimilation, translocation, and denitrification. Conversely, M. verticillatum showcased enrichment in genes linked to the reductive citric acid cycle (Arnon-Buchanan cycle), reductive pentose phosphate cycle (Calvin cycle), polyphosphate degradation, and organic nitrogen metabolism. In summary, our findings offer valuable insights into the diversity and function of epiphytic bacteria on submerged macrophyte leaves, shedding light on their roles in lake ecosystems.
Topics: Ecosystem; Lakes; Metagenome; Bacteria; Potamogetonaceae; Nitrogen
PubMed: 38286834
DOI: 10.1007/s00248-024-02346-7 -
Frontiers in Plant Science 2023In flowering plants, after being released from pollen grains, the male gametes use the style channel to migrate towards the ovary where they fertilize awaiting eggs....
In flowering plants, after being released from pollen grains, the male gametes use the style channel to migrate towards the ovary where they fertilize awaiting eggs. Environmental pathogens exploit the style passage, resulting in diseased progeny seed. The belief is that pollen also transmits pathogens into the style. By contrast, we hypothesized that pollen carries beneficial microbes that suppress environmental pathogens on the style passage. No prior studies have reported pollen-associated bacterial functions in any plant species. Here, bacteria were cultured from maize (corn) pollen encompassing wild ancestors and farmer-selected landraces from across the Americas, grown in a common field in Canada for one season. In total, 298 bacterial isolates were cultured, spanning 45 genera, 103 species, and 88 OTUs, dominated by , and . Full-length 16S DNA-based taxonomic profiling showed that 78% of bacterial taxa from the major wild ancestor of maize (Parviglumis teosinte) were present in at least one cultivated landrace. The species names of the bacterial isolates were used to search the pathogen literature systematically; this preliminary evidence predicted that the vast majority of the pollen-associated bacteria analyzed are not maize pathogens. The pollen-associated bacteria were tested against a style-invading pathogen shown to cause Gibberella ear rot (GER): 14 isolates inhibited this pathogen. Genome mining showed that all the anti- bacterial species encode , associated with biosynthesis of the natural fungicide, phenazine. To mimic the male gamete migration route, three pollen-associated bacterial strains were sprayed onto styles (silks), followed by inoculation; these bacteria reduced GER symptoms and mycotoxin accumulation in progeny seed. Confocal microscopy was used to search for direct evidence that pollen-associated bacteria can defend living silks against (); bacterial strain AS541 (), isolated from pollen of ancestral Parviglumis, was observed to colonize the susceptible style/silk entry points of (silk epidermis, trichomes, wounds). Furthermore, on style/silk tissue, AS541 colonized/aggregated on hyphae, and was associated with hyphal breaks. These results suggest that pollen has the potential to carry bacteria that can defend the style/silk passage against an environmental pathogen - a novel observation.
PubMed: 38269134
DOI: 10.3389/fpls.2023.1286199 -
Foods (Basel, Switzerland) Nov 2023The microbial community in donkey milk and its impact on the nutritional value of donkey milk are still unclear. We evaluated the effects of different lactation stages...
The microbial community in donkey milk and its impact on the nutritional value of donkey milk are still unclear. We evaluated the effects of different lactation stages on the composition and function of donkey milk microbiota. The milk samples were collected at 1, 30, 60, 90, 120, 150, and 180 days post-delivery. The result showed that the microbial composition and functions in donkey milk were significantly affected by different lactation stages. The dominant bacterial phyla in donkey milk are (60%) and (22%). (39%), (4%), and (2%) were the predominant bacterial genera detected in all milk samples. In the mature milk, the abundance of lactic acid bacteria (7%) was higher. (5%) and (3%) were more plentiful in milk samples from middle and later lactation stages (90-180 d). Furthermore, the pathogens and and thermoduric bacteria , , and were also detected. Donkey milk is rich in beneficial bacteria and also poses a potential health risk. The above findings have improved our understanding of the composition and function changes of donkey milk microbiota, which is beneficial for the rational utilization of donkey milk.
PubMed: 38231735
DOI: 10.3390/foods12234272 -
Microbiology Resource Announcements Feb 2024We report the discovery and genome sequence of CandC, a lytic bacteriophage with siphovirus morphology. CandC was isolated from a soil sample from Plattsburgh, NY, USA...
We report the discovery and genome sequence of CandC, a lytic bacteriophage with siphovirus morphology. CandC was isolated from a soil sample from Plattsburgh, NY, USA (Fall 2021). It has a genome size of 62,344 bp with 106 predicted protein-encoding genes, 30 of which are assigned putative functions.
PubMed: 38231186
DOI: 10.1128/mra.01117-23 -
Applied Microbiology and Biotechnology Dec 2024Marine bacteria living in association with marine sponges have proven to be a reliable source of biologically active secondary metabolites. However, no studies have yet...
Marine bacteria living in association with marine sponges have proven to be a reliable source of biologically active secondary metabolites. However, no studies have yet reported natural products from Microbacterium testaceum spp. We herein report the isolation of a M. testaceum strain from the sponge Tedania brasiliensis. Molecular networking analysis of bioactive pre-fractionated extracts from culture media of M. testaceum enabled the discovery of testacosides A-D. Analysis of spectroscopic data and chemical derivatizations allowed the identification of testacosides A-D as glycoglycerolipids bearing a 1-[α-glucopyranosyl-(1 → 3)-(α-mannopyranosyl)]-glycerol moiety connected to 12-methyltetradecanoic acid for testacoside A (1), 14-methylpentadecanoic acid for testacoside B (2), and 14-methylhexadecanoic acid for testacosides C (3) and D (4). The absolute configuration of the monosaccharide residues was determined by H-NMR analysis of the respective diastereomeric thiazolidine derivatives. This is the first report of natural products isolated from cultures of M. testaceum. KEY POINTS: • The first report of metabolites produced by Microbacterium testaceum. • 1-[α-Glucopyranosyl-(1 → 3)-(α-mannopyranosyl)]-glycerol lipids isolated and identified. • Microbacterium testaceum strain isolated from the sponge Tedania brasiliensis.
Topics: Animals; Glycerol; Porifera; Actinomycetales; Magnetic Resonance Spectroscopy; Biological Products; Microbacterium; Glycolipids
PubMed: 38217254
DOI: 10.1007/s00253-023-12870-0 -
Frontiers in Microbiology 2023The taxonomic relationships of 10 strains isolated from seaweeds collected from two beaches in Republic of Korea were studied by sequencing and analyses of 16S rRNA...
The taxonomic relationships of 10 strains isolated from seaweeds collected from two beaches in Republic of Korea were studied by sequencing and analyses of 16S rRNA genes and whole genomes. For the construction of a more reliable and robust 16S rRNA gene phylogeny, the authentic and nearly complete 16S rRNA gene sequences of all the type strains were selected through pairwise comparison of the sequences contained in several public databases including the List of Prokaryotic names with Standing in Nomenclature (LPSN). The clustering of the ten study strains into five distinct groups was apparent in this single gene-based phylogenetic tree. In addition, the 16S rRNA gene sequences of a few type strains were shown to be incorrectly listed in LPSN. An overall phylogenomic clustering of the genus was performed with a total of 113 genomes by core genome analysis. As a result, nine major (≥ three type strains) and eight minor (two type strains) clusters were defined mostly at gene support index of 92 and mean intra-cluster OrthoANIu of >80.00%. All of the study strains were assigned to a clade and distributed further into four subclusters in the core genome-based phylogenetic tree. phenotypic assays for physiological, biochemical, and chemotaxonomic characteristics were also carried out with the ten study strains and seven closely related type strains. Comparison of the overall genomic relatedness indices (OGRI) including OrthoANIu and digital DNA-DNA hybridization supported that the study strains constituted four new species of the genus . In addition, some type strains were reclassified as members of preexisting species. Moreover, some of them were embedded in a new genus of the family based on their distinct separation in the core genome-based phylogenetic tree and amino acid identity matrices. Based on the results here, four new species, namely, sp. nov., sp. nov., sp. nov., and sp. nov., are described, along with the proposal of gen. nov. containing five reclassified species from the " clade", with gen. nov., comb. nov. as the type species.
PubMed: 38164402
DOI: 10.3389/fmicb.2023.1299950 -
The Science of the Total Environment Feb 2024A naturally occurring multispecies bacterial community composed of Bacillus cereus and two novel bacteria (Microbacterium forte sp. nov. and Stenotrophomonas goyi sp....
A naturally occurring multispecies bacterial community composed of Bacillus cereus and two novel bacteria (Microbacterium forte sp. nov. and Stenotrophomonas goyi sp. nov.) has been identified from a contaminated culture of the microalga Chlamydomonas reinhardtii. When incubated in mannitol- and yeast extract-containing medium, this bacterial community can promote and sustain algal hydrogen production up to 313 mL H·L for 17 days and 163.5 mL H·L for 25 days in high-cell (76.7 μg·mL of initial chlorophyll) and low-cell density (10 μg·mL of initial chlorophyll) algal cultures, respectively. In low-cell density algal cultures, hydrogen production was compatible with algal growth (reaching up to 60 μg·mL of chlorophyll). Among the bacterial community, M. forte sp. nov. was the sole responsible for the improvement in hydrogen production. However, algal growth was not observed in the Chlamydomonas-M. forte sp. nov. consortium during hydrogen-producing conditions (hypoxia), suggesting that the presence of B. cereus and S. goyi sp. nov. could be crucial to support the algal growth during hypoxia. Still, under non‑hydrogen producing conditions (aerobiosis) the Chlamydomonas-M. forte sp. nov. consortium allowed algal growth (up to 40 μg·mL of chlorophyll) and long-term algal viability (>45 days). The genome sequence and growth tests of M. forte sp. nov. have revealed that this bacterium is auxotroph for biotin and thiamine and unable to use sulfate as sulfur source; it requires S-reduced forms such as cysteine and methionine. Cocultures of Chlamydomonas reinhardtii and M. forte sp. nov. established a mutualistic association: the alga complemented the nutrient deficiencies of the bacterium, while the bacterium released ammonium (0.19 mM·day) and acetic acid (0.15 mM·day) for the alga. This work offers a promising avenue for photohydrogen production concomitant with algal biomass generation using nutrients not suitable for mixotrophic algal growth.
Topics: Chlamydomonas reinhardtii; Microbacterium; Chlorophyll; Chlamydomonas; Acetic Acid; Bacteria; Hypoxia; Hydrogen
PubMed: 38159768
DOI: 10.1016/j.scitotenv.2023.169559 -
Food Chemistry: X Dec 2023Pyrroloquinoline quinone disodium (PQQ·Na) has been considered a human food supplement for human health promotion with its antioxidant properties. To determine whether...
Pyrroloquinoline quinone disodium (PQQ·Na) has been considered a human food supplement for human health promotion with its antioxidant properties. To determine whether PQQ·Na had similar functions to improve the antioxidant ability of layers and eggs, 180 laying hens were fed with 0 or 0.4 mg/kg PQQ·Na diets. Supplementation with PQQ·Na increased the albumen height, Haugh unit of the eggs. PQQ·Na also led to a higher glutathione peroxidase (GSH-Px) concentration in plasma and a lower malondialdehyde (MDA) content in the liver and egg yolk. Similarly, liver gene and protein expression of nuclear factor erythroid 2-related 2 (Nrf2) and heme oxygenase 1 (HO-1) were up-regulated by PQQ·Na Moreover, PQQ·Na increased the abundance of , and in gut. Overall, these results suggested PQQ·Na increased the antioxidant ability of layers and eggs which might be in connection with the activation of the Nrf2/HO-1 pathway and optimized gut microflora.
PubMed: 38144785
DOI: 10.1016/j.fochx.2023.101021 -
Microbiology Resource Announcements Feb 2024BabyYoda and Lynlen are two cluster EB phages that were discovered at Thiel College using NRRL B-24224. Both BabyYoda and Lynlen are predicted to be lytic, with...
BabyYoda and Lynlen are two cluster EB phages that were discovered at Thiel College using NRRL B-24224. Both BabyYoda and Lynlen are predicted to be lytic, with siphovirus morphologies, with genome sizes of 41,557 and 41,448 base pairs, respectively.
PubMed: 38132671
DOI: 10.1128/mra.01006-23 -
Frontiers in Microbiology 2023Chinese plum ( Lindl.) is a nutritionally and economically important stone fruit widely grown around the world. Anthracnose, caused by spp., is one of the primary...
Chinese plum ( Lindl.) is a nutritionally and economically important stone fruit widely grown around the world. Anthracnose, caused by spp., is one of the primary biotic stress factors limiting plum production. Medicinal plants may harbor rhizospheric or endophytic microorganisms that produce bioactive metabolites that can be used as anthracnose biocontrol agents. Here, 27 bacterial isolates from the medicinal plant with diverse antagonistic activities against were screened. Based on morphological, physiological, biochemical, and molecular characterization, 25 of these isolates belong to different species of genus , one to , and one more to . Eight representative strains showed high biocontrol efficacy against plum anthracnose in a pot experiment. In addition, several isolates showed a broad spectrum of inhibitory activity against a variety of fungal phytopathogens. Analysis of the volatile organic compound profile of these eight representative strains revealed a total of 47 compounds, most of which were ketones, while the others included alkanes, alkenes, alcohols, pyrazines, and phenols. Overall, this study confirmed the potential value of eight bacterial isolates for development as anthracnose biocontrol agents.
PubMed: 38130944
DOI: 10.3389/fmicb.2023.1296755