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Molecules (Basel, Switzerland) Oct 2021Gram-negative bacterial cell surface component lipopolysaccharide (LPS) and its active principle, lipid A, exhibit immunostimulatory effects and have the potential to... (Review)
Review
Gram-negative bacterial cell surface component lipopolysaccharide (LPS) and its active principle, lipid A, exhibit immunostimulatory effects and have the potential to act as adjuvants. However, canonical LPS acts as an endotoxin by hyperstimulating the immune response. Therefore, LPS and lipid A must be structurally modified to minimize their toxic effects while maintaining their adjuvant effect for application as vaccine adjuvants. In the field of chemical ecology research, various biological phenomena occurring among organisms are considered molecular interactions. Recently, the hypothesis has been proposed that LPS and lipid A mediate bacterial-host chemical ecology to regulate various host biological phenomena, mainly immunity. Parasitic and symbiotic bacteria inhabiting the host are predicted to possess low-toxicity immunomodulators due to the chemical structural changes of their LPS caused by co-evolution with the host. Studies on the chemical synthesis and functional evaluation of their lipid As have been developed to test this hypothesis and to apply them to low-toxicity and safe adjuvants.
Topics: Adjuvants, Immunologic; Animals; Bacteria; Endotoxins; Humans; Lipid A; Lipopolysaccharides
PubMed: 34684874
DOI: 10.3390/molecules26206294 -
Molecules (Basel, Switzerland) Sep 2021The use of selenium nanoparticles (SeNPs) in the biomedical area has been increasing as an alternative to the growing bacterial resistance to antibiotics. In this...
The use of selenium nanoparticles (SeNPs) in the biomedical area has been increasing as an alternative to the growing bacterial resistance to antibiotics. In this research, SeNPs were synthesized by green synthesis using ascorbic acid (AsAc) as a reducing agent and methanolic extract of L. flowers as a stabilizer. Characterization of SeNPs was performed by UV-vis spectrophotometry, infrared spectrophotometry (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) techniques. SeNPs of 40-60 nm and spherical morphologies were obtained. The antibacterial activity of marigold extracts and fractions was evaluated by disk diffusion methodology. The evaluation of SeNPs at different incubation times was performed through the colony-forming unit (CFU) count, in both cases against , , and bacteria. Partial antibacterial activity was observed with methanolic extracts of marigold leaves and flowers and total inhibition with SeNPs from 2 h for , 1 h for , and 30 min for In addition, SeNPs were found to exhibit antioxidant activity. The results indicate that SeNPs present a potentiated effect of both antimicrobial and antioxidant activity compared to the individual use of marigold extracts or sodium selenite (NaSeO). Their application emerges as an alternative for the control of clinical pathogens.
Topics: Anti-Bacterial Agents; Antioxidants; Bacteria; Calendula; Humans; Nanoparticles; Plant Extracts; Selenium
PubMed: 34641478
DOI: 10.3390/molecules26195929 -
Journal, Genetic Engineering &... Oct 2021Mining for precious metals is detrimental to the composition of soil structure and microbial diversity distribution and is a health risk to human communities around the...
BACKGROUND
Mining for precious metals is detrimental to the composition of soil structure and microbial diversity distribution and is a health risk to human communities around the affected communities. This study was aimed at determining the physical and chemical characteristics and diversity of bacteria in the soil of local mining sites for biosorption of heavy metals.
RESULTS
Results of physical and chemical characteristics showed mean pH values and percentage organic carbon to range from 7.1 to 8.2 and 0.18 to 1.12% respectively with statistical significance between sampling sites (P ≤ 0.05). Similarly, cation exchange capacity, electrical conductivity, moisture, total nitrogen, and carbon/nitrogen ratio (C:N) in the soil ranged between 1.52 to 3.57 cmol/kg, 0.15 to 0.32 ds/m, 0.14 to 0.82%, 0.10 to 0.28%, and 1.7 to 4.8 respectively. The highest heavy metal concentration of 59.01 ppm was recorded in soils obtained from site 3. The enumeration of viable aerobic bacteria recorded the highest mean count of 4.5 × 10 cfu/g observed at site 2 with statistical significance (P ≤ 0.05) between the sampled soils. Alcaligenes faecalis strain UBI, Aeromonas sp. strain UBI, Aeromonas sobria, and Leptothrix ginsengisoli that make up 11.2% of total identified bacteria were able to grow in higher amended concentrations of heavy metals. The evolutionary relationship showed the four heavy metal-tolerant bacteria identified belonged to the phylum Proteobacteria of class Betaproteobacteria in the order Burkholderiales. Heavy metal biosorption by the bacteria showed Alcaligenes faecalis strain UBI having the highest uptake capacity of 73.5% for Cu.
CONCLUSION
In conclusion, Alcaligenes faecalis strain UBI (MT107249) and Aeromonas sp. strain UBI (MT126242) identified in this study showed promising capability to withstand heavy metals and are good candidates in genetic modification for bioremediation.
PubMed: 34633566
DOI: 10.1186/s43141-021-00251-x -
Microbiology Resource Announcements Sep 2021Alcaligenes faecalis is a Gram-negative rod that is ubiquitous in the environment and is an opportunistic human pathogen. Here, we report the whole-genome sequencing...
Alcaligenes faecalis is a Gram-negative rod that is ubiquitous in the environment and is an opportunistic human pathogen. Here, we report the whole-genome sequencing analysis of A. faecalis HZ01, which presents mycobacterial growth inhibitory activity and was isolated from a contaminated culture of Mycobacterium chubuense ATCC 27278.
PubMed: 34591668
DOI: 10.1128/MRA.00521-21 -
Antimicrobial Agents and Chemotherapy Oct 2021The minocycline susceptibility of 3,856 isolates including , , , , and Stenotrophomonas maltophilia from the SENTRY surveillance (2014 to 2019) were analyzed. The...
The minocycline susceptibility of 3,856 isolates including , , , , and Stenotrophomonas maltophilia from the SENTRY surveillance (2014 to 2019) were analyzed. The susceptibilities of these species (%S) were spp. ( = 411; 92.6%), Burkholderia cepacia species complex ( = 199; 85.9%), spp. ( = 127; 99.2%), spp. ( = 59; 94.9%), Alcaligenes faecalis ( = 42; 88.1%), and S. maltophilia ( = 2,287; 99.5%). These data suggest that minocycline is a useful treatment option for infections caused by unusual Gram-negative pathogens.
Topics: Anti-Bacterial Agents; Burkholderia cepacia complex; Gram-Negative Bacterial Infections; Humans; Microbial Sensitivity Tests; Minocycline; Stenotrophomonas maltophilia
PubMed: 34491809
DOI: 10.1128/AAC.01264-21 -
Frontiers in Immunology 2021spp., including , is a gram-negative facultative bacterium uniquely residing inside the Peyer's patches. We previously showed that -derived lipopolysaccharides ( LPS)...
spp., including , is a gram-negative facultative bacterium uniquely residing inside the Peyer's patches. We previously showed that -derived lipopolysaccharides ( LPS) acts as a weak agonist of toll-like receptor 4 to activate dendritic cells and shows adjuvant activity by enhancing IgG and Th17 responses to systemic vaccination. Here, we examined the efficacy of LPS as a nasal vaccine adjuvant. Nasal immunization with ovalbumin (OVA) plus LPS induced follicular T helper cells and germinal center formation in the nasopharynx-associated lymphoid tissue (NALT) and cervical lymph nodes (CLNs), and consequently enhanced OVA-specific IgA and IgG responses in the respiratory tract and serum. In addition, nasal immunization with OVA plus LPS induced OVA-specific T cells producing IL-17 and/or IL-10, whereas nasal immunization with OVA plus cholera toxin (CT) induced OVA-specific T cells producing IFN-γ and IL-17, which are recognized as pathogenic type of Th17 cells. In addition, CT, but not LPS, promoted the production of TNF-α and IL-5 by T cells. Nasal immunization with OVA plus CT, but not LPS, led to increased numbers of neutrophils and eosinophils in the nasal cavity. Together, these findings indicate that the benign nature of LPS is an effective nasal vaccine adjuvant that induces antigen-specific mucosal and systemic immune responses without activation of inflammatory cascade after nasal administration.
Topics: Adjuvants, Vaccine; Administration, Intranasal; Alcaligenes faecalis; Animals; Female; Immunoglobulin A; Lipopolysaccharides; Mice; Mice, Inbred BALB C; Ovalbumin; Th17 Cells
PubMed: 34276692
DOI: 10.3389/fimmu.2021.699349 -
PloS One 2021Microbes have been identified as fundamental for the good health of bees, acting as pathogens, protective agent against infection/inorganic toxic compounds, degradation...
Microbes have been identified as fundamental for the good health of bees, acting as pathogens, protective agent against infection/inorganic toxic compounds, degradation of recalcitrant secondary plant metabolites, definition of social group membership, carbohydrate metabolism, honey and bee pollen production. However, study of microbiota associated with bees have been largely confined to the honeybees and solitary bees. Here, I characterized the microbiota of indoor surface nest of four brazilian stingless bee species (Apidae: Meliponini) with different construction behaviors and populations. Bees that use predominantly plant material to build the nest (Frieseomelitta varia and Tetragonisca angustula) have a microbiome dominated by bacteria found in the phylloplane and flowers such as Pseudomonas sp. and Sphingomonas sp. Species that use mud and feces (Trigona spinipes) possess a microbiome dominated by coliforms such as Escherichia coli and Alcaligenes faecalis. Melipona quadrifasciata, which uses both mud / feces and plant resin, showed a hybrid microbiome with microbes found in soil, feces and plant material. These findings indicate that indoor surface microbiome varies widely among bees and reflects the materials used in the construction of the nests.
Topics: Animals; Bacteria; Bees; Honey; Microbiota
PubMed: 34242231
DOI: 10.1371/journal.pone.0252933 -
MBio Jun 2021In marine environments, the bacterially induced metamorphosis of larvae is a widespread cross-kingdom communication phenomenon that is critical for the persistence of...
In marine environments, the bacterially induced metamorphosis of larvae is a widespread cross-kingdom communication phenomenon that is critical for the persistence of many marine invertebrates. However, the majority of inducing bacterial signals and underlying cellular mechanisms remain enigmatic. The marine hydroid Hydractinia echinata is a well-known model system for investigating bacterially stimulated larval metamorphosis, as larvae transform into the colonial adult stage within 24 h of signal detection. Although has served as a cell biological model system for decades, the identity and influence of bacterial signals on the morphogenic transition remained largely unexplored. Using a bioassay-guided analysis, we first determined that specific bacterial (lyso)phospholipids, naturally present in bacterial membranes and vesicles, elicit metamorphosis in larvae in a dose-response manner. Lysophospholipids, as single compounds or in combination (50 μM), induced metamorphosis in up to 50% of all larvae within 48 h. Using fluorescence-labeled bacterial phospholipids, we demonstrated that phospholipids are incorporated into the larval membranes, where interactions with internal signaling cascades are proposed to occur. Second, we identified two structurally distinct exopolysaccharides of bacterial biofilms, the new Rha-Man polysaccharide from sp. strain P1-9 and curdlan from Alcaligenes faecalis, to induce metamorphosis in up to 75% of tested larvae. We also found that combinations of (lyso)phospholipids and curdlan induced transformation within 24 h, thereby exceeding the morphogenic activity observed for single compounds and bacterial biofilms. Our results demonstrate that two structurally distinct, bacterium-derived metabolites converge to induce high transformation rates of larvae and thus may help ensure optimal habitat selection. Bacterial biofilms profoundly influence the recruitment and settlement of marine invertebrates, critical steps for diverse marine processes such as the formation of coral reefs, the maintenance of marine fisheries, and the fouling of submerged surfaces. However, the complex composition of biofilms often makes the characterization of individual signals and regulatory mechanisms challenging. Developing tractable model systems to characterize these coevolved interactions is the key to understanding fundamental processes in evolutionary biology. Here, we characterized two types of bacterial signaling molecules, phospholipids and polysaccharides, that induce the morphogenic transition. We then analyzed their abundance and combinatorial activity. This study highlights the general importance of multiple bacterial signal converging activity in development-related cross-kingdom signaling and poses the question of whether complex lipids and polysaccharides are general metamorphic cues for cnidarian larvae.
Topics: Animals; Biofilms; Coral Reefs; Ecosystem; Hydrozoa; Larva; Metamorphosis, Biological
PubMed: 34154406
DOI: 10.1128/mBio.00401-21 -
Molecules (Basel, Switzerland) Apr 2021The present study was aimed to evaluate the suitability of agro-wastes and crude vegetable oils for the cost-effective production of poly-β-hydroxybutyrate (PHB), to...
The present study was aimed to evaluate the suitability of agro-wastes and crude vegetable oils for the cost-effective production of poly-β-hydroxybutyrate (PHB), to evaluate growth kinetics and PHB production in RZS4 and sp. RZS1 with these carbon substrates and to study the biodegradation of PHB accumulated by these cultures. RZS4 and sp. RZS1 accumulates higher amounts of PHB corn (79.90% of dry cell mass) and rice straw (66.22% of dry cell mass) medium respectively. The kinetic model suggests that the sp. RZS1 follows the Monod model more closely than RZS4. Both the cultures degrade their PHB extract under the influence of PHB depolymerase. Corn waste and rice straw appear as the best and cost-effective substrates for the sustainable production of PHB from RZS4 and sp. RZS1. The biopolymer accumulated by these organisms is biodegradable in nature. The agro-wastes and crude vegetable oils are good and low-cost sources of nutrients for the growth and production of PHB and other metabolites. Their use would lower the production cost of PHB and the low-cost production will reduce the sailing price of PHB-based products. This would promote the large-scale commercialization and popularization of PHB as an ecofriendly bioplastic/biopolymer.
Topics: Agriculture; Alcaligenes; Biodegradation, Environmental; Biomass; Biopolymers; Fermentation; Kinetics; Plastics; Pseudomonas; Spectrum Analysis; Waste Products
PubMed: 33922162
DOI: 10.3390/molecules26092443 -
Nutrients Apr 2021β-glucan consumption is known for its beneficial health effects, but the mode of action is unclear. While humans and mice lack the required enzymes to digest...
β-glucan consumption is known for its beneficial health effects, but the mode of action is unclear. While humans and mice lack the required enzymes to digest β-glucans, certain intestinal microbes can digest β-glucans, triggering gut microbial changes. Curdlan, a particulate β-glucan isolated from , is used as a food additive. In this study we determined the effect of curdlan intake in mice on the intestinal microbiota and dextran sodium sulfate (DSS)-induced intestinal inflammation. The effect of curdlan on the human intestinal microbiota was assessed using i-screen, an assay for studying anaerobic microbial interactions. Mice received oral gavage with vehicle or curdlan for 14 days followed by DSS for 7 days. The curdlan-fed group showed reduced weight loss and colonic inflammation compared to the vehicle-fed group. Curdlan intake did not induce general microbiota community changes, although a specific , closely related to , was observed to be 10- to 100-fold more prevalent in the curdlan-fed group under control and colitis conditions, respectively. When tested in i-screen, curdlan induced a global change in the microbial composition of the healthy intestinal microbiota from a human. Overall, these results suggest that dietary curdlan induces microbiota changes that could reduce intestinal inflammation.
Topics: Animals; Bifidobacterium; Colitis; Colon; Dextran Sulfate; Diet; Gastrointestinal Microbiome; Humans; Mice; beta-Glucans
PubMed: 33920960
DOI: 10.3390/nu13041305