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Scientific Reports Mar 2021Due to their antimicrobial properties, silver nanoparticles (AgNPs) are used in a wide range of consumer products that includes topical wound dressings, coatings for...
Due to their antimicrobial properties, silver nanoparticles (AgNPs) are used in a wide range of consumer products that includes topical wound dressings, coatings for biomedical devices, and food-packaging to extend the shelf-life. Despite their beneficial antimicrobial effects, developmental exposure to such AgNPs may lead to gut dysbiosis and long-term health consequences in exposed offspring. AgNPs can cross the placenta and blood-brain-barrier to translocate in the brain of offspring. The underlying hypothesis tested in the current study was that developmental exposure of male and female mice to AgNPs disrupts the microbiome-gut-brain axis. To examine for such effects, C57BL6 female mice were exposed orally to AgNPs at a dose of 3 mg/kg BW or vehicle control 2 weeks prior to breeding and throughout gestation. Male and female offspring were tested in various mazes that measure different behavioral domains, and the gut microbial profiles were surveyed from 30 through 120 days of age. Our study results suggest that developmental exposure results in increased likelihood of engaging in repetitive behaviors and reductions in resident microglial cells. Echo-MRI results indicate increased body fat in offspring exposed to AgNPs exhibit. Coprobacillus spp., Mucispirillum spp., and Bifidobacterium spp. were reduced, while Prevotella spp., Bacillus spp., Planococcaceae, Staphylococcus spp., Enterococcus spp., and Ruminococcus spp. were increased in those developmentally exposed to NPs. These bacterial changes were linked to behavioral and metabolic alterations. In conclusion, developmental exposure of AgNPs results in long term gut dysbiosis, body fat increase and neurobehavioral alterations in offspring.
Topics: Animals; Behavior; Dysbiosis; Female; Gastrointestinal Microbiome; Humans; Male; Maze Learning; Mental Status and Dementia Tests; Metagenome; Metagenomics; Metal Nanoparticles; Mice; Models, Animal; Silver
PubMed: 33753813
DOI: 10.1038/s41598-021-85919-7 -
Nucleic Acids Research Apr 2021Argonaute proteins are programmable nucleases that are found in both eukaryotes and prokaryotes and provide defense against invading genetic elements. Although some...
Argonaute proteins are programmable nucleases that are found in both eukaryotes and prokaryotes and provide defense against invading genetic elements. Although some prokaryotic argonautes (pAgos) were shown to recognize RNA targets in vitro, the majority of studied pAgos have strict specificity toward DNA, which limits their practical use in RNA-centric applications. Here, we describe a unique pAgo nuclease, KmAgo, from the mesophilic bacterium Kurthia massiliensis that can be programmed with either DNA or RNA guides and can precisely cleave both DNA and RNA targets. KmAgo binds 16-20 nt long 5'-phosphorylated guide molecules with no strict specificity for their sequence and is active in a wide range of temperatures. In bacterial cells, KmAgo is loaded with small DNAs with no obvious sequence preferences suggesting that it can uniformly target genomic sequences. Mismatches between the guide and target sequences greatly affect the efficiency and precision of target cleavage, depending on the mismatch position and the nature of the reacting nucleic acids. Target RNA cleavage by KmAgo depends on the formation of secondary structure indicating that KmAgo can be used for structural probing of RNA. These properties of KmAgo open the way for its use for highly specific nucleic acid detection and cleavage.
Topics: Argonaute Proteins; Bacterial Proteins; DNA, Bacterial; Planococcaceae; Protein Binding; RNA, Bacterial; Substrate Specificity
PubMed: 33744962
DOI: 10.1093/nar/gkab182 -
Journal of Dairy Science Apr 2021The growth of psychrotolerant aerobic spore-forming bacteria during refrigerated storage often results in the spoilage of fluid milk, leading to off-flavors and...
The growth of psychrotolerant aerobic spore-forming bacteria during refrigerated storage often results in the spoilage of fluid milk, leading to off-flavors and curdling. Because of their low toxicity, biodegradability, selectivity, and antimicrobial activity over a range of conditions, glycolipids are a novel and promising intervention to control undesirable microbes. The objective of this study was to determine the efficacy of a commercial glycolipid product to inhibit spore germination, spore outgrowth, and the growth of vegetative cells of Paenibacillus odorifer, Bacillus weihenstephanensis, and Viridibacillus arenosi, which are the predominant spore-forming spoilage bacteria in milk. For spore germination and outgrowth assays, varying concentrations (25-400 mg/L) of the glycolipid product were added to commercial UHT whole and skim milk inoculated with ∼4 log spores/mL of each bacteria and incubated at 30°C for 5 d. Inhibition of spore germination in inoculated UHT whole milk was only observed for V. arenosi, and only when glycolipid was added at 400 mg/L. However, concentrations of 400 and 200 mg/L markedly inhibited the outgrowth of vegetative cells from spores of P. odorifer and B. weihenstephanensis, respectively. No inhibition of spore germination or outgrowth was observed in inoculated UHT skim milk for any strain at the concentrations tested (25 and 50 mg/L). The effect of glycolipid addition on vegetative cell growth in UHT whole and skim milk when inoculated with ∼4 log cfu/mL of each bacteria was also determined over 21 d of storage at 7°C. Glycolipid addition at 50 mg/L was bactericidal against P. odorifer and B. weihenstephanensis in inoculated UHT skim milk through 21 d of storage, whereas 100 mg/L was needed for similar control of V. arenosi. Concentrations of 100 and 200 mg/L inhibited the growth of vegetative cells of B. weihenstephanensis and P. odorifer, respectively, in inoculated UHT whole milk, whereas 200 mg/L was also bactericidal to B. weihenstephanensis. Additional studies are necessary to identify effective concentrations for the inhibition of Viridibacillus spp. growth in whole milk beyond 7 d. Findings from this study demonstrate that natural glycolipids have the potential to inhibit the growth of dairy-spoilage bacteria and extend the shelf life of milk.
Topics: Animals; Anti-Infective Agents; Glycolipids; Milk; Paenibacillus; Planococcaceae; Spores; Spores, Bacterial
PubMed: 33589263
DOI: 10.3168/jds.2020-19769 -
PloS One 2021Microbial-induced calcium carbonate precipitation (MICP) is a biological process inducing biomineralization of CaCO3. This can be used to form a solid, concrete-like...
Microbial-induced calcium carbonate precipitation (MICP) is a biological process inducing biomineralization of CaCO3. This can be used to form a solid, concrete-like material. To be able to use MICP successfully to produce solid materials, it is important to understand the formation process of the material in detail. It is well known that crystallization surfaces can influence the precipitation process. Therefore, we present in this contribution a systematic study investigating the influence of calcite seeds on the MICP process. We focus on the changes in the pH and changes of the optical density (OD) signal measured with absorption spectroscopy to analyze the precipitation process. Furthermore, optical microscopy was used to visualize the precipitation processes in the sample and connect them to changes in the pH and OD. We show, that there is a significant difference in the pH evolution between samples with and without calcite seeds present and that the shape of the pH evolution and the changes in OD can give detailed information about the mineral precipitation and transformations. In the presented experiments we show, that amorphous calcium carbonate (ACC) can also precipitate in the presence of initial calcite seeds and this can have implications for consolidated MICP materials.
Topics: Biomineralization; Calcium Carbonate; Carbonates; Chemical Precipitation; Construction Materials; Microscopy; Minerals; Soil; Sporosarcina
PubMed: 33561160
DOI: 10.1371/journal.pone.0240763 -
PloS One 2021In recent years, Sporosarcina pasteurii (S. pasteurii) has become one of the most popular bacteria in microbially induced calcium carbonate precipitation (MICP). Various...
In recent years, Sporosarcina pasteurii (S. pasteurii) has become one of the most popular bacteria in microbially induced calcium carbonate precipitation (MICP). Various applications have been developed based on the efficient urease that can induce the precipitation of calcium carbonate. However, the metabolic mechanism related to biomineralization of S. pasteurii has not been clearly elucidated. The process of bacterial culture and biomineralization consumes a large amount of urea or ammonium salts, which are usually used as agricultural fertilizers, not to mention probable environmental pollutions caused by the excessive use of these raw materials. Therefore, it is urgent to reveal the mechanism of nitrogen utilization and metabolism of S. pasteurii. In this paper, we compared the growth and gene expression of S. pasteurii under three different culture conditions through transcriptome analyses. GO and KEGG analyses revealed that both ammonium and urea were direct nitrogen sources of S. pasteurii, and the bacteria could not grow normally in the absence of ammonium or urea. To the best of our knowledge, this paper is the first one to reveal the nitrogen utilization mechanism of S. pasteurii through transcriptome methods. Furthermore, the presence of ammonium might promote the synthesis of intracellular ATP and enhance the motility of the bacteria. There should be an ATP synthesis mechanism associated with urea hydrolysis catalyzed by urease in S. pasteurii.
Topics: Adenosine Triphosphate; Ammonium Compounds; Biosynthetic Pathways; Cell Wall; Down-Regulation; Flagella; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Gene Ontology; Genes, Bacterial; Nitrogen; Sporosarcina; Transcriptome; Up-Regulation; Urea; Urease
PubMed: 33561150
DOI: 10.1371/journal.pone.0246818 -
Nucleic Acids Research Feb 2021Argonaute (Ago) proteins are conserved nucleic acid-guided proteins present in all domains of life. Eukaryotic Argonaute proteins (eAgos) are key players in RNA...
Argonaute (Ago) proteins are conserved nucleic acid-guided proteins present in all domains of life. Eukaryotic Argonaute proteins (eAgos) are key players in RNA interference pathways and function as RNA-guided RNA endonucleases at physiological temperatures. Although eAgos are considered to evolve from prokaryotic Argonaute proteins (pAgos), previously studied pAgos were unable to catalyze RNA-guided RNA cleavage at physiological temperatures. Here, we describe a distinctive pAgo from mesophilic bacteria Kurthia massiliensis (KmAgo). KmAgo utilizes DNA guides to cleave single-stranded DNA (ssDNA) and RNA targets with high activity. KmAgo also utilizes RNA guides to cleave ssDNA and RNA targets at moderate temperatures. We show that KmAgo can use 5' phosphorylated DNA guides as small as 9-mers to cut ssDNA and RNA, like Clostridium butyricum Ago. Small DNA binding confers remarkable thermostability on KmAgo, and we can suppress the guide-independent plasmid processing activity of empty KmAgo by elevating the DNA guide loaded temperature. Moreover, KmAgo performs programmable cleavage of double-stranded DNA and highly structured RNA at 37°C. Therefore, KmAgo can be regarded as a DNA-guided programmable omnipotent nuclease for cleaving most types of nucleic acids efficiently. This study broadens our understanding of Ago proteins and could expand the pAgo-based DNA and RNA manipulation toolbox.
Topics: Argonaute Proteins; Bacterial Proteins; Cations, Divalent; DNA Breaks, Double-Stranded; DNA, Single-Stranded; Planococcaceae; RNA; Temperature
PubMed: 33444443
DOI: 10.1093/nar/gkaa1278 -
Scientific Reports Jan 2021Human activities interfere with wild animals and lead to the loss of many animal populations. Therefore, efforts have been made to understand how wildlife can rebound...
Human activities interfere with wild animals and lead to the loss of many animal populations. Therefore, efforts have been made to understand how wildlife can rebound from anthropogenic disturbances. An essential mechanism to adapt to environmental and social changes is the fluctuations in the host gut microbiome. Here we give a comprehensive description of anthropogenically induced microbiome alterations in Asian elephants (n = 30). We detected gut microbial changes due to overseas translocation, captivity and deworming. We found that microbes belonging to Planococcaceae had the highest contribution in the microbiome alterations after translocation, while Clostridiaceae, Spirochaetaceae and Bacteroidia were the most affected after captivity. However, deworming significantly changed the abundance of Flavobacteriaceae, Sphingobacteriaceae, Xanthomonadaceae, Weeksellaceae and Burkholderiaceae. These findings may provide fundamental ideas to help guide the preservation tactics and probiotic replacement therapies of a dysbiosed gut microbiome in Asian elephants. More generally, these results show the severity of anthropogenic activities at the level of gut microbiome, altering the adaptation processes to new environments and the subsequent capability to maintain normal physiological processes in animals.
Topics: Adaptation, Physiological; Animals; Asia; Dysbiosis; Ecosystem; Elephants; Environmental Monitoring; Female; Gastrointestinal Microbiome; Male
PubMed: 33436882
DOI: 10.1038/s41598-020-80537-1 -
Scientific Reports Dec 2020Microbial induced calcite precipitation (MICP) based on ureolysis has a high potential for many applications, e.g. restoration of construction materials. The...
Microbial induced calcite precipitation (MICP) based on ureolysis has a high potential for many applications, e.g. restoration of construction materials. The gram-positive bacterium Sporosarcina pasteurii is the most commonly used microorganism for MICP due to its high ureolytic activity. However, Sporosarcina pasteurii is so far cultivated almost exclusively in complex media, which only results in moderate biomass concentrations at the best. Cultivation of Sporosarcina pasteurii must be strongly improved in order to make technological application of MICP economically feasible. The growth of Sporosarcina pasteurii DSM 33 was boosted by detecting auxotrophic deficiencies (L-methionine, L-cysteine, thiamine, nicotinic acid), nutritional requirements (phosphate, trace elements) and useful carbon sources (glucose, maltose, lactose, fructose, sucrose, acetate, L-proline, L-alanine). These were determined by microplate cultivations with online monitoring of biomass in a chemically defined medium and systematically omitting or substituting medium components. Persisting growth limitations were also detected, allowing further improvement of the chemically defined medium by the addition of glutamate group amino acids. Common complex media based on peptone and yeast extract were supplemented based on these findings. Optical density at the end of each cultivation of the improved peptone and yeast extract media roughly increased fivefold respectively. A maximum OD600 of 26.6 ± 0.7 (CDW: 17.1 ± 0.5 g/L) was reached with the improved yeast extract medium. Finally, culture performance and media improvement was analysed by measuring the oxygen transfer rate as well as the backscatter during shake flask cultivation.
Topics: Bacterial Physiological Phenomena; Carbon; Culture Media; Hydrogen-Ion Concentration; Microbiological Techniques; Nutritional Requirements; Sporosarcina
PubMed: 33384450
DOI: 10.1038/s41598-020-79904-9 -
Molecules (Basel, Switzerland) Dec 2020AJ003 produces glycosyl-4,4'-diaponeurosporen-4'-ol-4-oic acid as its main carotenoid. Five carotenoid pathway genes were presumed to be present in the genome of...
AJ003 produces glycosyl-4,4'-diaponeurosporen-4'-ol-4-oic acid as its main carotenoid. Five carotenoid pathway genes were presumed to be present in the genome of AJ003; however, 4,4-diaponeurosporene oxidase (CrtP) was non-functional, and a gene encoding aldehyde dehydrogenase (AldH) was not identified. In the present study, a genome mining approach identified two missing enzymes, CrtP2 and AldH2454, in the glycosyl-4,4'-diaponeurosporen-4'-ol-4-oic acid biosynthetic pathway. Moreover, CrtP2 and AldH enzymes were functional in heterologous and generated two carotenoid aldehydes (4,4'-diapolycopene-dial and 4,4'-diaponeurosporene-4-al) and two carotenoid carboxylic acids (4,4'-diaponeurosporenoic acid and 4,4'-diapolycopenoic acid). Furthermore, the genes encoding CrtP2 and AldH2454 were located at a distance the carotenoid gene cluster of .
Topics: Aldehyde Dehydrogenase; Carotenoids; Databases, Protein; Genome, Bacterial; Metabolic Networks and Pathways; Oxidoreductases; Planococcaceae
PubMed: 33322786
DOI: 10.3390/molecules25245892 -
The ISME Journal Jan 2021Enrichment of protective microbiota in the rhizosphere facilitates disease suppression. However, how the disruption of protective rhizobacteria affects disease...
Enrichment of protective microbiota in the rhizosphere facilitates disease suppression. However, how the disruption of protective rhizobacteria affects disease suppression is largely unknown. Here, we analyzed the rhizosphere microbial community of a healthy and diseased tomato plant grown <30-cm apart in a greenhouse at three different locations in South Korea. The abundance of Gram-positive Actinobacteria and Firmicutes phyla was lower in diseased rhizosphere soil (DRS) than in healthy rhizosphere soil (HRS) without changes in the causative Ralstonia solanacearum population. Artificial disruption of Gram-positive bacteria in HRS using 500-μg/mL vancomycin increased bacterial wilt occurrence in tomato. To identify HRS-specific and plant-protective Gram-positive bacteria species, Brevibacterium frigoritolerans HRS1, Bacillus niacini HRS2, Solibacillus silvestris HRS3, and Bacillus luciferensis HRS4 were selected from among 326 heat-stable culturable bacteria isolates. These four strains did not directly antagonize R. solanacearum but activated plant immunity. A synthetic community comprising these four strains displayed greater immune activation against R. solanacearum and extended plant protection by 4 more days in comparison with each individual strain. Overall, our results demonstrate for the first time that dysbiosis of the protective Gram-positive bacterial community in DRS promotes the incidence of disease.
Topics: Actinobacteria; Bacillus; Bacteria; Firmicutes; Incidence; Solanum lycopersicum; Planococcaceae; Plant Diseases; Ralstonia solanacearum; Rhizosphere; Soil Microbiology
PubMed: 33028974
DOI: 10.1038/s41396-020-00785-x