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Multilamellar and Multivesicular Outer Membrane Vesicles Produced by a Buttiauxella agrestis Mutant.Applied and Environmental Microbiology Oct 2020Outer membrane vesicles (OMVs) are naturally released from Gram-negative bacteria and play important roles in various biological functions. Released vesicles are not...
Outer membrane vesicles (OMVs) are naturally released from Gram-negative bacteria and play important roles in various biological functions. Released vesicles are not uniform in shape, size, or characteristics, and little is known about this diversity of OMVs. Here, we show that deletion of , which encodes a part of the Tol-Pal system, leads to the production of multiple types of vesicles and increases overall vesicle production in the high-vesicle-forming type strain JCM 1090. The Δ mutant produced small OMVs and multilamellar/multivesicular OMVs (M-OMVs) as well as vesicles with a striking similarity to the wild type. M-OMVs, previously undescribed, contained triple-lamellar membrane vesicles and multiple vesicle-incorporating vesicles. Ultracentrifugation enabled the separation and purification of each type of OMV released from the Δ mutant, and visualization by quick-freeze deep-etch and replica electron microscopy indicated that M-OMVs are composed of several lamellar membranes. Visualization of intracellular compartments of Δ mutant cells showed that vesicles were accumulated in the broad periplasm, which is probably due to the low linkage between the outer and inner membranes attributed to the Tol-Pal defect. The outer membrane was invaginating inward by wrapping a vesicle, and the precursor of M-OMVs existed in the cell. Thus, we demonstrated a novel type of bacterial OMV and showed that unconventional processes enable the Δ mutant to form unique vesicles. Membrane vesicle (MV) formation has been recognized as a common mechanism in prokaryotes, and MVs play critical roles in intercellular interaction. However, a broad range of MV types and their multiple production processes make it difficult to gain a comprehensive understanding of MVs. In this work, using vesicle separation and electron microscopic analyses, we demonstrated that diverse types of outer membrane vesicles (OMVs) were released from an engineered strain, JCM 1090 Δ mutant. We also discovered a previously undiscovered type of vesicle, multilamellar/multivesicular outer membrane vesicles (M-OMVs), which were released by this mutant using unconventional processes. These findings have facilitated considerable progress in understanding MV diversity and expanding the utility of MVs in biotechnological applications.
Topics: Bacterial Proteins; Enterobacteriaceae; Mutation; Periplasmic Proteins
PubMed: 32801184
DOI: 10.1128/AEM.01131-20 -
Poultry Science Oct 2019Adequate dietary Ca and available phosphorus (avP) are essential to long-term egg production and bone health in laying hens. The effects of dietary Ca and avP levels and...
Adequate dietary Ca and available phosphorus (avP) are essential to long-term egg production and bone health in laying hens. The effects of dietary Ca and avP levels and Buttiauxella sp. phytase (BSP) were studied in Lohmann LSL Lite hens from 30 to 70 wk of age (woa). Hens (n = 456; 4 per cage) were fed either a primary breeder recommendation-based diet (positive control; PC); the PC with avP and Ca levels reduced by 0.146 and 0.134% of the diet, respectively, without (NC) or with 300 FTU/kg BSP (NC+BSP). Egg production, BW, feed intake, FCR, and eggshell quality from 30 to 70 woa, and apparent ileal digestibility of P (AIDP) and Ca (AIDCa), and bone quality at 32, 48, and 70 woa were measured. The avP and Ca levels in the NC diet were not clinically deficient, as most parameters were unaffected by diet. Hen BW from 34 to 70 woa tended to be 2.9% greater (P = 0.076) for PC and NC+BSP compared to NC. Mid-diaphysis cortical bone mineral content (CBMC) tended to be 10% and 9% higher (P = 0.065) in the NC+BSP hens than in NC hens at 48 and 70 woa, respectively. AIDP of NC+BSP was 24% greater (P = 0.034) than of NC at 32 woa and tended to be 18% greater (P = 0.082) than AIDP of PC at 48 woa, and 25% lower than of NC and PC at 70 woa (P = 0.028). AIDCa was 25% lower for NC+BSP than PC at 48 woa only (P = 0.037). The avP and Ca sufficiency in the NC diet limited the opportunity to determine a phytase effect. Although the supplemental BSP tended to increase BW and 48 and 70 woa CBMC, and increased 32 woa AIDP, the efficacy of BSP could not be determined due to the lack of an NC effect on most parameters. Commercial laying hens can maintain health and productivity at lower than recommended levels of dietary Ca and avP; phytase supplementation may allow for even further reductions.
Topics: 6-Phytase; Animal Feed; Animals; Bone and Bones; Calcium; Chickens; Diet; Dietary Supplements; Digestion; Egg Shell; Enterobacteriaceae; Female; Ileum; Phosphorus
PubMed: 31032860
DOI: 10.3382/ps/pez220 -
Journal of Animal Science May 2019This study evaluated the effects of increasing the dose of a 6-phytase from Buttiauxella on phytate degradation, mineral, energy, and AA digestibility in weaned pigs fed...
Increasing the dosing of a Buttiauxella phytase improves phytate degradation, mineral, energy, and amino acid digestibility in weaned pigs fed a complex diet based on wheat, corn, soybean meal, barley, and rapeseed meal1.
This study evaluated the effects of increasing the dose of a 6-phytase from Buttiauxella on phytate degradation, mineral, energy, and AA digestibility in weaned pigs fed complex diets based on wheat, corn, soybean meal, barley, and rapeseed meal. A negative control (NC) diet containing no added inorganic phosphorus (P) and a reduction of 0.1% calcium (Ca) and 36 kcal/kg ME was supplemented with Buttiauxella phytase at 0, 250, 500, 1,000, or 2,000 FTU/kg diet and tested against a nutritionally adequate, positive control (PC) diet. One phytase units (FTU) is the amount of enzyme that liberates 1 micromole of inorganic phosphate per minute from a sodium phytate substrate at pH 5.5 and 37 °C. Barrows (Topigs × Pietrian; initial mean body weight 19.3 kg) were housed individually in metabolic crates and fed the test diets in mash form via 2 equal meals per day for 9 d (fed at 2.5 times the maintenance energy requirement), with 8 replicate pigs per treatment, in 2 experimental runs (total n = 48). After a 3-d adaptation period, urine and feces were collected over 5 d for measurements of apparent total tract digestibility (ATTD) and retention of nutrients. On day 9, pigs were euthanized and ileal digesta collected for measurements of apparent ileal digestibility (AID) of nutrients. Phytase improved (P < 0.05) digestibility of all measured AA except Trp (P < 0.1), and AID P, nitrogen, phytate, ATTD P, Ca versus NC. Increasing phytase dose from 0 (NC) to 2,000 FTU/kg increased AID Lys, Cys, Thr, Val, Ile, Leu, mean AA, P, N, phytate, ATTD P, N, Na, energy, ME, P retention (g/d), and reduced P excretion (g/d) in a linear or exponential manner (P < 0.05). Phytase at 2,000 FTU/kg improved AA digestibility by between +3.1 percentage points (Trp) and +8.8 percentage points (Cys) versus NC (average +6.3 percentage points) (P < 0.05). Phytase inclusion at 2,000 FTU/kg reduced P excretion (g/d) by 57% versus PC (P < 0.05). In conclusion, increasing Buttiauxella phytase in the range of 0 to 2,000 FTU/kg increased phytate degradation, improved AA and P digestibility, and reduced P excretion in weaned pigs fed complex diets.
Topics: 6-Phytase; Amino Acids; Animal Feed; Animals; Brassica rapa; Calcium, Dietary; Diet; Dietary Supplements; Digestion; Enterobacteriaceae; Feces; Gastrointestinal Tract; Hordeum; Minerals; Phytic Acid; Glycine max; Swine; Triticum; Zea mays
PubMed: 31056701
DOI: 10.1093/jas/skz151 -
Frontiers in Veterinary Science 2021The gut microbiota contributes to host health by maintaining homeostasis and improving digestive efficiency. Therefore, identifying gut microbes will shed light on the...
The gut microbiota contributes to host health by maintaining homeostasis and improving digestive efficiency. Therefore, identifying gut microbes will shed light on the annual life cycle of animals and in particular those that are threatened or endangered. Nonetheless, the gut microbial composition of the majority of bird species is still unknown. Here, for the first time, 16S rRNA gene sequencing was used to characterize and compare the community composition and diversity of gut microbiotas from six species of birds raised at the Wildlife Conservation Center in Baotou, China: relict gull (; = 3), muscovy duck (; = 3), ruddy shelduck (; = 3), demoiselle crane (; = 4), whooper swan (; = 3), and black swan (; = 5). A total of 26,616 operational taxonomic units from 21 samples were classified into 32 phyla and 507 genera. Chao1, Shannon diversity, observed species, and Simpson index analysis revealed differences in the community richness and diversity between the different species. Proteobacteria was the dominant bacterial phylum in whooper swan and relict gull, whereas Firmicutes was the dominant bacterial phylum in the other species. At the genus level, 11 dominant genera were detected (, and ). Principal component and cluster analyses revealed that, while the microbial community composition of different individuals of the same species clustered together, the gut microbial composition varied between the bird species. Furthermore, the most abundant bacterial species differed between bird species. Because many avian gut microbes are derived from the diet, the eating habits and natural living environment of birds may be important contributing factors to the observed differences. Short-term changes to the diet and living environment have little effect on the composition of the avian gut microbiota. This study provides a theoretical basis for bird protection, including disease prevention and control.
PubMed: 34957285
DOI: 10.3389/fvets.2021.791287 -
Microbiological Research Jul 2021The association of different species of endophytic bacteria with the rhizosphere of the host plants can stimulate growth, development and acclimatization, offering a...
The association of different species of endophytic bacteria with the rhizosphere of the host plants can stimulate growth, development and acclimatization, offering a greater quantity of seedlings, in addition to reducing the cycle, providing economic return to the producer. The objective of this study was to evaluate the effect of introduction four bacterial isolates through inoculation into the root system in three banana cultivars (Prata Anã, Grande Naine and BRS Princesa) in the acclimatization phase. The evaluated treatments were: control (nutrient broth without bacteria); Bacillus cereus strain 1 (BC1); Bacillus cereus strain 2 (BC2); Bacillus thuringiensis (BT); Buttiauxella agrestis (BA). The morphological characteristics related to the development of the plants (total height and pseudostem diameter) were evaluated throughout the acclimatization period. After 90 days of transplanting and acclimatization, root length, leaf number, dry root weight, pseudostem and leaf, leaf area, internal carbon concentration, stomatal conductance, photosynthesis rate, transpiration rate, leaf temperature and chlorophyll were evaluated. The bacteria showed different results in relation to the studied cultivars. Considering the morphological and physiological characteristics observed in this study, B. thuringiensis for the cultivars Prata Anã and Grande Naine and the B. agrestis for the cultivar BRS Princesa are recommended for the process of acclimatization of banana seedlings, as they stimulated growth of the plant, increasing the dry mass, besides promoting the growth of roots. In this way, they improved the physiological aspects of the plants and reduced the period of acclimatization of the banana.
Topics: Adaptation, Physiological; Agricultural Inoculants; Bacillus; Chlorophyll; Endophytes; Enterobacteriaceae; Musa; Photosynthesis; Plant Roots; Seedlings
PubMed: 33765636
DOI: 10.1016/j.micres.2021.126750 -
Frontiers in Microbiology 2021Whether terrestrial life can withstand the martian environment is of paramount interest for planetary protection measures and space exploration. To understand microbial...
Whether terrestrial life can withstand the martian environment is of paramount interest for planetary protection measures and space exploration. To understand microbial survival potential in Mars-like conditions, several fungal and bacterial samples were launched in September 2019 on a large NASA scientific balloon flight to the middle stratosphere (∼38 km altitude) where radiation levels resembled values at the equatorial Mars surface. Fungal spores of and bacterial cells of , subsp. , and sp. MASE-IM-9 were launched inside the MARSBOx (Microbes in Atmosphere for Radiation, Survival, and Biological Outcomes Experiment) payload filled with an artificial martian atmosphere and pressure throughout the mission profile. The dried microorganisms were either exposed to full UV-VIS radiation (UV dose = 1148 kJ m) or were shielded from radiation. After the 5-h stratospheric exposure, samples were assayed for survival and metabolic changes. Spores from the fungus and cells from the Gram-(-) bacterium were the most resistant with a 2- and 4-log reduction, respectively. Exposed sp. MASE-IM-9 was completely inactivated (both with and without UV exposure) and subsp. only survived the UV shielded experimental condition (3-log reduction). Our results underscore a wide variation in survival phenotypes of spacecraft associated microorganisms and support the hypothesis that pigmented fungi may be resistant to the martian surface if inadvertently delivered by spacecraft missions.
PubMed: 33692763
DOI: 10.3389/fmicb.2021.601713 -
PeerJ 2017Algae encompass a wide array of photosynthetic organisms that are ubiquitously distributed in aquatic and terrestrial habitats. Algal species often bloom in aquatic...
BACKGROUND
Algae encompass a wide array of photosynthetic organisms that are ubiquitously distributed in aquatic and terrestrial habitats. Algal species often bloom in aquatic ecosystems, providing a significant autochthonous carbon input to the deeper anoxic layers in stratified water bodies. In addition, various algal species have been touted as promising candidates for anaerobic biogas production from biomass. Surprisingly, in spite of its ecological and economic relevance, the microbial community involved in algal detritus turnover under anaerobic conditions remains largely unexplored.
RESULTS
Here, we characterized the microbial communities mediating the degradation of (Chlorophyta), sp. strain IWP1 (Charophyceae), and kelp (phylum Phaeophyceae), using sediments from an anaerobic spring (Zodlteone spring, OK; ZDT), sludge from a secondary digester in a local wastewater treatment plant (Stillwater, OK; WWT), and deeper anoxic layers from a seasonally stratified lake (Grand Lake O' the Cherokees, OK; GL) as inoculum sources. Within all enrichments, the majority of algal biomass was metabolized within 13-16 weeks, and the process was accompanied by an increase in cell numbers and a decrease in community diversity. Community surveys based on the V4 region of the 16S rRNA gene identified different lineages belonging to the phyla Bacteroidetes, Proteobacteria (alpha, delta, gamma, and epsilon classes), Spirochaetes, and Firmicutes that were selectively abundant under various substrate and inoculum conditions. Within all kelp enrichments, the microbial communities structures at the conclusion of the experiment were highly similar regardless of the enrichment source, and were dominated by the genus , or family within the Firmicutes. In all other enrichments the final microbial community was dependent on the inoculum source, rather than the type of algae utilized as substrate. Lineages enriched included the uncultured groups VadinBC27 and WCHB1-69 within the Bacteroidetes, genus and the uncultured group SHA-4 within Spirochaetes, , , , , and within the Firmicutes, and genera , , and and within the Gamma-Proteobaceteria order Enterobacteriales.
CONCLUSIONS
Our results represent the first systematic survey of microbial communities mediating turnover of algal biomass under anaerobic conditions, and highlights the diversity of lineages putatively involved in the degradation process.
PubMed: 28097050
DOI: 10.7717/peerj.2803 -
Poultry Science Nov 2019This study evaluated the effects of a combination of xylanase, amylase, and protease (XAP), with probiotics (3 Bacillus spp.) supplementation on apparent ileal...
Effects of a combination of xylanase, amylase and protease, and probiotics on major nutrients including amino acids and non-starch polysaccharides utilization in broilers fed different level of fibers.
This study evaluated the effects of a combination of xylanase, amylase, and protease (XAP), with probiotics (3 Bacillus spp.) supplementation on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients in Cobb 500 broilers from 0 to 21 d. A completely randomized 2 × 4 factorial design (2 levels of fiber; 4 types of supplements) with 8 replicate cages (6 birds/cage) was used. Each low and high-fiber diet contained 500 FTU/kg Buttiauxella sp. phytase and was supplemented with: (a) none (control), (b) XAP (2,000 U xylanase + 200 U amylase + 4,000 U protease/kg diet), (c) probiotics (75,000 CFU/g of Bacillus spp.), or (d) XAP + probiotics. High fiber decreased (P < 0.05) nitrogen-corrected apparent metabolizable energy (AMEn), AID of all amino acids (AA), AID and ATTD of dry matter (DM), crude protein (CP), starch, and gross energy (GE). High fiber increased (P < 0.01) the flow of total non-starch polysaccharides (NSP) in both ileum and total tract. The XAP + probiotics increased (P < 0.01) AMEn as well as AID and ATTD of DM, CP, GE, starch, while alone, XAP yielded similar improvement except for DM compared with control. The supplemental XAP alone improved (P < 0.01) the digestibility of most of the AAs compared with control. Moreover, XAP + probiotics increased (P < 0.05) AID of all AA except arginine and serine compared with control. A fiber × supplements interaction (P < 0.05) was found for AID of histidine and threonine, and their digestibility in high-fiber diet was improved to a level comparable to low-fiber diet by XAP + probiotics. The flow of NSP in XAP group was 5 to 6% lower than in control while NSP flow in XAP + probiotic group was further 4% lower than that of XAP group (P < 0.01). The results infer that the combination of XAP and probiotics can effectively optimize the nutrient digestibility in broilers fed both low and high-fiber diets.
Topics: Amino Acids; Amylases; Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Chickens; Diet; Dietary Fiber; Dietary Supplements; Digestion; Dose-Response Relationship, Drug; Gastrointestinal Tract; Ileum; Nutrients; Peptide Hydrolases; Polysaccharides; Probiotics; Random Allocation; Xylosidases
PubMed: 31198939
DOI: 10.3382/ps/pez310 -
Interactions of semiconductor Cd-based quantum dots and Cd with gut bacteria isolated from wild fry.PeerJ 2022With the rapid development of nanotechnology, more and more nanoproducts are being released into the environment where they may both pose ecological risks and be toxic...
BACKGROUND
With the rapid development of nanotechnology, more and more nanoproducts are being released into the environment where they may both pose ecological risks and be toxic to living organisms. The ecotoxicological impact of quantum dots (QDs), a class of nanoparticles (NPs), on aquatic organisms is becoming an emerging issue, this due to their nano-specific properties, to the physico-chemical transformation in the environment and to the possible release of toxic metals from their structure such as Cd.
METHODS
In this work, (i) spectroscopic measurements of commercially available Cd-based QDs (CdSe/ZnS-COOH) were made at various pH values (5.0 and 7.0) to study their interactions (at a concentration of 4 nm) with various strains of Gram-positive and Gram-negative gut bacteria after short-term exposure and (ii) the antibacterial efficacy of QDs and Cd (at a concentration 0.09-3.56 mM) against gut bacteria isolated from wild freshwater fry was studied at different temperatures (15 °C and 25 °C) and pH values (5.0 and 7.0) by applying a well-established disc diffusion assay.
RESULTS
Twenty-six gut bacterial isolates from wild fry were identified as spp., , , , , sp., sp., sp., and sp. Cd-based (CdSe/ZnS-COOH) QDs at a concentration of 4 nm were found to be stable in aqueous media (with pH 7.0) or starting to form aggregates (at pH 5.0), thus, apparently, did not release heavy metals (HMs) into the media over 48 h in conditions of light or dark and did not show antibacterial efficacy on the gut bacteria isolated from wild fry after short-term (9 h and 48 h) incubations. Cd was found to produce significant dose-dependent toxic effects on bacterial growth, and the size of the inhibition zones on some of the tested strains significantly correlated with temperature. The most sensitive and the most resistant to Cd were the Gram-positive bacteria, for which the minimum inhibitory concentration (MIC) values of Cd were 0.09-0.27 mM and 3.11-3.29 mM respectively and varied significantly between the tested temperatures (15 °C and 25 °C). The MIC values of Cd for the Gram-negative bacteria (18 out of 22 strains) ranged from 0.44 to 0.71 mM and did not differ significantly between the tested temperatures. Among the selected Gram-positive and Gram-negative strains, those with the higher sensitivity towards Cd also revealed relatively stronger signals of QDs photoluminescence (PL) when transferred after incubation into fresh medium without QDs. In addition, the formation of endogenous metalloporphyrins observed spectroscopically in some bacterial strains indicates certain differences in metabolic activity that may play a protective role against potential oxidative damage.
Topics: Quantum Dots; Cadmium; Bacteria; Semiconductors; Anti-Bacterial Agents; Gram-Negative Bacteria
PubMed: 36128199
DOI: 10.7717/peerj.14025 -
Scientific Reports Feb 2022The effects of rare earth mining on rice biomass, rare earth element (REE) content and bacterial community structure was studied through pot experiment. The research...
The effects of rare earth mining on rice biomass, rare earth element (REE) content and bacterial community structure was studied through pot experiment. The research shows that the REE content in rice roots, shoots and grains was significantly positive correlated with that in soil, and the dry weight of rice roots, shoots and grains was highly correlated with soil physical and chemical properties, nutrient elements and REE contents; The exploitation of rare earth minerals inhibited a-diversity of endophytic bacteria in rhizosphere, root, phyllosphere and leaf of rice, significantly reduced the abundance index, OTU number, Chao, Ace index and also significantly reduced the diversity index-Shannon index, and also reduced uniformity index: Pielou's evenness index, which caused β-diversity of bacteria to be quite different. The exploitation of rare earth minerals reduces the diversity of bacteria, but forms dominant bacteria, such as Burkholderia, Bacillus, Buttiauxella, Acinetobacter, Bradyrhizobium, Candida koribacter, which can degrade the pollutants formed by exploitation of rare earth minerals, alleviate the compound pollution of rare earth and ammonia nitrogen, and also has the function of fixing nitrogen and resisting rare earth stress; The content of soil available phosphorus in no-mining area is lower, and the dominant bacteria of Pantoea formed in such soil, which has the function of improving soil phosphorus availability. Rare earth elements and physical and chemical properties of soil affect the community structure of bacteria in rhizosphere and phyllosphere of rice, promote the parallel movement of some bacteria in rhizosphere, root, phyllosphere and leaf of rice, promote the construction of community structure of bacteria in rhizosphere and phyllosphere of rice, give full play to the growth promoting function of Endophytes, and promote the growth of rice. The results showed that the exploitation of rare earth minerals has formed the dominant endophytic bacteria of rice and ensured the yield of rice in the mining area, however, the mining of mineral resources causes the compound pollution of rare earth and ammonia nitrogen, which makes REE content of rice in mining area significantly higher than that in non-mining area, and the excessive rare earth element may enter the human body through the food chain and affect human health, so the food security in the REE mining area deserves more attention.
Topics: Bacteria; Endophytes; Metals, Rare Earth; Microbiota; Oryza; Rhizosphere; Soil; Soil Microbiology
PubMed: 35136105
DOI: 10.1038/s41598-022-06003-2