Characterization of Iron-Oxides Formed by Oxidation of Ferrous Ions in the Presence of Various Bacterial Species and Inorganic Ligands

2004 ◽  
Vol 21 (2) ◽  
pp. 99-112 ◽  
Author(s):  
Xavier Châtellier ◽  
M. Marcia West ◽  
Jérôme Rose ◽  
Danielle Fortin ◽  
Gary G. Leppard ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Bacterial Species ◽  
Ferrous Ions ◽  
Inorganic Ligands

scholarly journals Nanopore-Sequencing Characterization of the Gut Microbiota of Melolontha melolontha Larvae: Contribution to Protection against Entomopathogenic Nematodes?

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 396
Author(s):  
Ewa Sajnaga ◽  
Marcin Skowronek ◽  
Agnieszka Kalwasińska ◽  
Waldemar Kazimierczak ◽  
Karolina Ferenc ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Entomopathogenic Nematodes ◽  
Bacterial Species ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Nanopore Sequencing ◽  
Bacterial Phyla ◽  
Melolontha Melolontha

This study focused on the potential relationships between midgut microbiota of the common cockchafer Melolontha melolontha larvae and their resistance to entomopathogenic nematodes (EPN) infection. We investigated the bacterial community associated with control and unsusceptible EPN-exposed insects through nanopore sequencing of the 16S rRNA gene. Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes were the most abundant bacterial phyla within the complex and variable midgut microbiota of the wild M. melolontha larvae. The core microbiota was found to include 82 genera, which accounted for 3.4% of the total number of identified genera. The EPN-resistant larvae differed significantly from the control ones in the abundance of many genera belonging to the Actinomycetales, Rhizobiales, and Clostridiales orders. Additionally, the analysis of the microbiome networks revealed different sets of keystone midgut bacterial genera between these two groups of insects, indicating differences in the mutual interactions between bacteria. Finally, we detected Xenorhabdus and Photorhabdus as gut residents and various bacterial species exhibiting antagonistic activity against these entomopathogens. This study paves the way to further research aimed at unravelling the role of the host gut microbiota on the output of EPN infection, which may contribute to enhancement of the efficiency of nematodes used in eco-friendly pest management.

scholarly journals Construction and Characterization of a proU-gfp Transcriptional Fusion That Measures Water Availability in a Microbial Habitat

2002 ◽  
Vol 68 (9) ◽  
pp. 4604-4612 ◽  
Author(s):  
Catherine A. Axtell ◽  
Gwyn A. Beattie
Keyword(s):  
Pseudomonas Syringae ◽  
Water Availability ◽  
Water Deprivation ◽  
Bacterial Species ◽  
Transcriptional Fusion ◽  
Bacterial Biosensor ◽  
E Coli ◽  
Quantitative Manner ◽  
Microbial Habitat

ABSTRACT We constructed and characterized a transcriptional fusion that measures the availability of water to a bacterial cell. This fusion between the proU promoter from Escherichia coli and the reporter gene gfp was introduced into strains of E. coli, Pantoea agglomerans, and Pseudomonas syringae. The proU-gfp fusion in these bacterial biosensor strains responded in a quantitative manner to water deprivation caused by the presence of NaCl, Na2SO4, KCl, or polyethylene glycol (molecular weight, 8000). The fusion was induced to a detectable level by NaCl concentrations of as low as 10 mM in all three bacterial species. Water deprivation induced proU-gfp expression in both planktonic and surface-associated cells; however, it induced a higher level of expression in the surface-associated cells. Following the introduction of P. agglomerans biosensor cells onto bean leaves, the cells detected a significant decrease in water availability within only 5 min. After 30 min, the populations were exposed, on average, to a water potential equivalent to that imposed by approximately 55 mM NaCl. These results demonstrate the effectiveness of a proU-gfp-based biosensor for evaluating water availability on leaves. Furthermore, the inducibility of proU-gfp in multiple bacterial species illustrates the potential for tailoring proU-gfp-based biosensors to specific habitats.

Preparation and Characterization of Iron Oxides – Polymer Composite Membranes

2012 ◽  
Vol 47 (9) ◽  
pp. 1390-1394 ◽  
Author(s):  
Gabriela Dudek ◽  
Roman Turczyn ◽  
Anna Strzelewicz ◽  
Aleksandra Rybak ◽  
Monika Krasowska ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Polymer Composite ◽  
Composite Membranes

scholarly journals Characterization of Ancient Red Iron Oxides Excavated from the Shimo-ohgibaru Archaeological Site in Kumamoto, Japan

2013 ◽  
Vol 60 (4) ◽  
pp. 146-153 ◽  
Author(s):  
Hiromi TSUJI ◽  
Ryu MURAKAMI ◽  
Takashi MIYAZAKI ◽  
Hideki HASHIMOTO ◽  
Teruaki DANNO ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Archaeological Site

scholarly journals An Overview of Metabolic Activity, Beneficial and Pathogenic Aspects of Burkholderia Spp

Metabolites ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 321
Author(s):  
Hazem S. Elshafie ◽  
Ippolito Camele
Keyword(s):  
Secondary Metabolites ◽  
Plant Growth ◽  
Biochemical Characterization ◽  
Bacterial Species ◽  
Promoting Effect ◽  
Important Species ◽  
Beneficial Effects ◽  
Plant Growth Promoting ◽  
Rhizosphere Competence

Burkholderia is an important bacterial species which has different beneficial effects, such as promoting the plant growth, including rhizosphere competence for the secretion of allelochemicals, production of antibiotics, and siderophores. In addition, most of Burkholderia species have demonstrated promising biocontrol action against different phytopathogens for diverse crops. In particular, Burkholderia demonstrates significant biotechnological potential as a source of novel antibiotics and bioactive secondary metabolites. The current review is concerned with Burkholderia spp. covering the following aspects: discovering, classification, distribution, plant growth promoting effect, and antimicrobial activity of different species of Burkholderia, shedding light on the most important secondary metabolites, their pathogenic effects, and biochemical characterization of some important species of Burkholderia, such as B. cepacia, B. andropogonis, B. plantarii, B. rhizoxinica, B. glumae, B. caryophylli and B. gladioli.

scholarly journals Characterization of Epigallocatechin-Gallate-Grafted Chitosan Nanoparticles and Evaluation of Their Antibacterial and Antioxidant Potential

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1375
Author(s):  
María J. Moreno-Vásquez ◽  
Maribel Plascencia-Jatomea ◽  
Saúl Sánchez-Valdes ◽  
Judith C. Tanori-Córdova ◽  
Francisco J. Castillo-Yañez ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Food Packaging ◽  
Inhibitory Concentration ◽  
Antioxidant Activities ◽  
Bacterial Species ◽  
Chitosan Nanoparticles ◽  
Epigallocatechin Gallate ◽  
Antioxidant Power ◽  
Ferric Reducing Antioxidant Power

Nanoparticles based on chitosan modified with epigallocatechin gallate (EGCG) were synthetized by nanoprecipitation (EGCG-g-chitosan-P). Chitosan was modified by free-radical-induced grafting, which was verified by Fourier transform infrared (FTIR). Furthermore, the morphology, particle size, polydispersity index, and zeta potential of the nanoparticles were investigated. The grafting degree of EGCG, reactive oxygen species (ROS) production, antibacterial and antioxidant activities of EGCG-g-chitosan-P were evaluated and compared with those of pure EGCG and chitosan nanoparticles (Chitosan-P). FTIR results confirmed the modification of the chitosan with EGCG. The EGCG-g-chitosan-P showed spherical shapes and smoother surfaces than those of Chitosan-P. EGCG content of the grafted chitosan nanoparticles was 330 μg/g. Minimal inhibitory concentration (MIC) of EGCG-g-chitosan-P (15.6 μg/mL) was lower than Chitosan-P (31.2 μg/mL) and EGCG (500 μg/mL) against Pseudomonas fluorescens (p < 0.05). Additionally, EGCG-g-chitosan-P and Chitosan-P presented higher Staphylococcus aureus growth inhibition (100%) than EGCG at the lowest concentration tested. The nanoparticles produced an increase of ROS (p < 0.05) in both bacterial species assayed. Furthermore, EGCG-g-chitosan-P exhibited higher antioxidant activity than that of Chitosan-P (p < 0.05) in 2,2′-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and ferric-reducing antioxidant power assays. Based on the above results, EGCG-g-chitosan-P shows the potential for food packaging and biomedical applications.

Physicochemical characterization of monazite sand and its associated bacterial species from the beaches of southeastern Brazil

2021 ◽  
Author(s):  
Marcos Tadeu D’Azeredo Orlando ◽  
Elson Silva Galvão ◽  
José Luis Passamai ◽  
Alan Bragança Zordan ◽  
Cintia Garrido Pinheiro Orlando ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Physicochemical Characterization ◽  
Southeastern Brazil

scholarly journals Discovery and Characterization of Low-Molecular Weight Inhibitors of Erwinia tracheiphila

2020 ◽  
Vol 110 (5) ◽  
pp. 989-998
Author(s):  
Cláudio M. Vrisman ◽  
Loïc Deblais ◽  
Yosra A. Helmy ◽  
Reed Johnson ◽  
Gireesh Rajashekara ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
High Throughput Screening ◽  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Bacillus Species ◽  
Erwinia Tracheiphila ◽  
Static Activity ◽  
Low Toxicity

Plant pathogenic bacteria in the genus Erwinia cause economically important diseases, including bacterial wilt of cucurbits caused by Erwinia tracheiphila. Conventional bactericides are insufficient to control this disease. Using high-throughput screening, 464 small molecules (SMs) with either cidal or static activity at 100 µM against a cucumber strain of E. tracheiphila were identified. Among them, 20 SMs (SM1 to SM20), composed of nine distinct chemical moiety structures, were cidal to multiple E. tracheiphila strains at 100 µM. These lead SMs had low toxicity to human cells and honey bees at 100 µM. No phytotoxicity was observed on melon plants at 100 µM, except when SM12 was either mixed with Silwet L-77 and foliar sprayed or when delivered through the roots. Lead SMs did not inhibit the growth of beneficial Pseudomonas and Enterobacter species but inhibited the growth of Bacillus species. Nineteen SMs were cidal to Xanthomonas cucurbitae and showed >50% growth inhibition against Pseudomonas syringae pv. lachrymans. In addition, 19 SMs were cidal or static against Erwinia amylovora in vitro. Five SMs demonstrated potential to suppress E. tracheiphila when foliar sprayed on melon plants at 2× the minimum bactericidal concentration. Thirteen SMs reduced Et load in melon plants when delivered via roots. Temperature and light did not affect the activity of SMs. In vitro cidal activity was observed after 3 to 10 h of exposure to these five SMs. Here, we report 19 SMs that provide chemical scaffolds for future development of bactericides against plant pathogenic bacterial species.

scholarly journals Characterization of planktonic and biofilm fatty acid profiles and evaluation of their trophic transfer potential to Hyalella Azteca

2021 ◽  
Author(s):  
Jerry Chien-Yao Chao
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Bacterial Species ◽  
Saturated Fatty Acids ◽  
Hyalella Azteca ◽  
Fatty Acid Profiles ◽  
Fa Composition ◽  
Branched Chain ◽  
Transfer Potential

Fatty acid (FA) composition between biofilms and batch planktonic cultures were compared for two bacterial species Pseudomonas aeruginosa and Staphylococcus aureaus. Biofilm cultures exhibited decrease in saturated fatty acids (SAFA) that potentially conform to a more fluidic biophysical membrane property. The amount of FA in the biofilms' extracellular polymeric substance was not sufficient to consider it having a major contribution to the observed differences between biofilms and batch planktonic cultures. While biofilm grazing by the amphipod Hyalella azteca was evident, only certain bacteria-specific FA appeared to have the potential to be retained (odd-number SAFA and branched-chain FA). H. azteca with diet strictly consisted of bacteria biofilms did not demonstrate significant changes in their nutritional condition in terms of ω-3 and ω-6 polyunsaturated fatty acids (PUFA): combined with the results from fasting trials, H. azteca appears to have the capacity to retain ω-3 and ω-6 PUFAs up to 10 days.

scholarly journals Characterization of prodiginine compounds produced by a Vibrio species isolated from salt flat sediment along the Florida Gulf Coast

Fine Focus ◽  
2017 ◽  
Vol 3 (1) ◽  
pp. 33-51 ◽  
Author(s):  
Stephanie Morgan ◽  
Matthew J. Thomas ◽  
Katherine M. Walstrom ◽  
Eric C. Warrick ◽  
Brittany J. Gasper
Keyword(s):  
Gulf Coast ◽  
Bacterial Species ◽  
Whole Genome ◽  
Medicinal Uses ◽  
Salt Flat ◽  
Florida Gulf Coast ◽  
Flash Column Chromatography ◽  
Vibrio Genus ◽  
Pink Pigment

Prodiginines are secondary metabolites produced by several known species of bacteria. These metabolites are known for their bright pigmentation and their potential medicinal uses. Biosynthesis of prodiginine compounds, including the well-studied prodigiosin, has been well characterized in Serratia marcescens and other bacterial species, including several marine bacteria. In an effort to isolate and identify natural products from marine organisms, an environmental sample was taken from a salt flat along the Florida Gulf Coast and cultured for bacterial growth. A bacterial species that produces a vibrant pink pigment was isolated and identified as a member of the Vibrio genus and was named MI-2. Whole genome sequencing identified a 13-gene operon with homology to the S. marcescens prodigiosin biosynthetic operon. The pigment produced by MI-2 was hypothesized to be composed of prodigiosin or related prodiginine compounds and was purified by flash column chromatography and identified by mass spectrometry.

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