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Frontiers in Microbiology 2024Distilled grain waste (DGW) is rich in nutrients and can be a potential resource as animal feed. However, DGW contains as much as 14% lignin, dramatically reducing the...
Distilled grain waste (DGW) is rich in nutrients and can be a potential resource as animal feed. However, DGW contains as much as 14% lignin, dramatically reducing the feeding value. White-rot fungi such as could preferentially degrade lignin with high efficiency. However, lignin derivatives generated during alcohol distillation inhibit growth. Thus, finding a new strategy to adjust the DGW properties to facilitate growth is critical for animal feed preparation and DGW recycling. In this study, three dominant indigenous bacteria, including X1, X3, and 15F were chosen to generate single and compound microbial inoculums for DGW composting to prepare substrates for growth. Compared with non-inoculated control or single microbial inoculation, all composite inoculations, especially the three-microbial compound, led to faster organic metabolism, shorter composting process, and improved physicochemical properties of DGW. growth assays showed the fastest mycelial colonization (20.43 μg·g ergosterol) and extension (9 mm/d), the highest ligninolytic enzyme activities (Lac, 152.68 U·g; Lip, 15.56 U·g; MnP, 0.34 U·g; Xylanase, 10.98 U·g; FPase, 0.71 U·g), and the highest lignin degradation ratio (30.77%) in the DGW sample after 12 h of composting with the three-microbial compound inoculation when compared to other groups. This sample was relatively abundant in bacteria playing critical roles in amino acid, carbohydrate, energy metabolism, and xenobiotic biodegradation, as suggested by metagenomic analysis. The feed value analysis revealed that mycelia full colonization in composted DGW led to high fiber content retention and decreased lignin content (final ratio of 5% lignin) but elevated protein concentrations (about 130 g·kg DM). An additional daily weight gain of 0.4 kg/d was shown in cattle feeding experiments by replacing 60% of regular feed with it. These findings demonstrate that compound inoculant consisting of three indigenous microorganisms is efficient to compost DGW and facilitate growth. decreased the lignin content of composted DGW during its mycelial growth, improving the quality of DGW for feeding cattle.
PubMed: 38881654
DOI: 10.3389/fmicb.2024.1405564 -
Ecotoxicology and Environmental Safety Jun 2024Copper (Cu) serves as an essential cofactor in all organisms, yet excessive Cu exposure is widely recognized for its role in inducing liver inflammation. However, the...
Copper (Cu) serves as an essential cofactor in all organisms, yet excessive Cu exposure is widely recognized for its role in inducing liver inflammation. However, the precise mechanism by which Cu triggers liver inflammation in ducks, particularly in relation to the interplay in gut microbiota regulation, has remained elusive. In this investigation, we sought to elucidate the impact of Cu exposure on liver inflammation through gut-liver axis in ducks. Our findings revealed that Cu exposure markedly elevated liver AST and ALT levels and induced liver inflammation through upregulating pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and triggering the LPS/TLR4/NF-κB signaling pathway. Simultaneously, Cu exposure induced alterations in the composition of intestinal flora communities, notably increasing the relative abundance of Sphingobacterium, Campylobacter, Acinetobacter and reducing the relative abundance of Lactobacillus. Cu exposure significantly decreased the protein expression related to intestinal barrier (Occludin, Claudin-1 and ZO-1) and promoted the secretion of intestinal pro-inflammatory cytokines. Furthermore, correlation analysis was observed that intestinal microbiome and gut barrier induced by Cu were closely related to liver inflammation. Fecal microbiota transplantation (FMT) experiments further demonstrated the microbiota-depleted ducks transplanting fecal samples from Cu-exposed ducks disturbed the intestinal dysfunction, which lead to impaire liver function and activate the liver inflammation. Our study provided insights into the mechanism by which Cu exposure induced liver inflammation in ducks through the regulation of gut-liver axis. These results enhanced our comprehension of the potential mechanisms driving Cu-induced hepatotoxicity in avian species.
Topics: Animals; Gastrointestinal Microbiome; Toll-Like Receptor 4; Ducks; Signal Transduction; Liver; Lipopolysaccharides; Copper; Cytokines; Inflammation; Chemical and Drug Induced Liver Injury
PubMed: 38718729
DOI: 10.1016/j.ecoenv.2024.116430 -
Microorganisms Apr 2024Carbapenems are last-resort antibiotics used to treat multidrug-resistant bacterial infections. Resistance to carbapenems has been designated as an urgent threat and is...
Carbapenems are last-resort antibiotics used to treat multidrug-resistant bacterial infections. Resistance to carbapenems has been designated as an urgent threat and is increasing in healthcare settings. However, little is still known about the distribution and characteristics of carbapenem-resistant bacteria (CRB) outside of healthcare settings. Here, we surveyed the distribution of CRB in ten diverse freshwater and seawater environments in California, U.S., ranging from San Luis Obispo County to San Bernardino County, combining both direct isolation and enrichment approaches to increase the diversity of isolated CRB. From the locations surveyed, we selected 30 CRB for further characterization. These isolates were identified as members of the genera , , , , , , and . These isolates were resistant to carbapenems, other β-lactams, and often to other antibiotics (tetracycline, gentamicin, or ciprofloxacin). We also found that nine isolates belonging to the genera , (), and () produced carbapenemases. Overall, our findings indicate that sampling different types of aquatic environments and combining different isolation approaches increase the diversity of the environmental CRB obtained. Moreover, our study supports the increasingly recognized role of natural water systems as an underappreciated reservoir of bacteria resistant to carbapenems and other antibiotics, including bacteria carrying carbapenemase genes.
PubMed: 38674746
DOI: 10.3390/microorganisms12040802 -
Plant Disease Apr 2024Cauliflower mushroom (Sparassis latifolia), is widely distributed in Australia, North America, Europe, and East Asia (Bashir et al., 2020). It is known for its medicinal...
Cauliflower mushroom (Sparassis latifolia), is widely distributed in Australia, North America, Europe, and East Asia (Bashir et al., 2020). It is known for its medicinal significance due to the availability of various pharmacological substances and their use in health supplements (Bashir et al., 2017). In recent years, with the development of artificial cultivation technology, S. latifolia has been industrialized in China, with an annual output value 50 million dollars. In March 2023, approximately 15% of S. latifolia showed obvious bacterial rot in mushroom hothouse (about 0.05 ha), located in Shuangliu county, Sichuan province, China (104°7'51"N, 30°25'2"E). The affected parts appear water-soaked, and become sunken and softened as the disease progresses. In the finally, all the fruiting body tissues turn into paste, with colors pale yellow, and have a foul smell. The pathogen was isolated from the margin of the lesions by dilution and streaking techniques onto Nutrient Agar, and incubated at 28℃ in the dark for 2-3 days. A single colony was re-streak for purification. Eight isolates were obtained from five samples collected randomly. The representative three isolates were selected for further characterization. For pathogenicity testing, ten health fruit bodies of S. latifolia were selected (for per isolate). Bacterial suspensions (1 × 107 CFU/ml) of the three isolates were applied to the fruiting body until wet, sterile water was used as controls. All the S. latifolia were maintained at 19±1℃, 85-100% relative humidity, and 18 h of light in the mushroom hothouse. Three days later, the inoculated fruiting bodies developed yellow color, and appear water-soaked, five days later, fruiting body gradually turn to soft and part turn to rot, seven days later, the fruiting body tissues completely turn into paste with a foul smell. The symptoms exhibited were similar to those of the original diseased fruiting bodies, while the control group remained healthy. The same bacterial were re-isolated from the infected fruiting bodies and subsequently identified by morphological characteristics and DNA sequenced. The pathogenicity test was conducted three times, each yielding similar results. The colonies of the pathogen are gram-negative rods, medium sized, convex, smooth, opaque, turning yellow after several days at a temperature 28℃. For molecular identification, the DNA of the representative three isolates was extracted using a Bacterial Genomic DNA Extraction Kit (Solarbio, Beijing). The 16S rRNA genes were amplified and sequenced with the primer 27F/1492R (Lane et al., 1985). Finally, the sequences were identical. The generated representative sequence was deposited in GenBank with accession number OR399122. BLASTn analysis showed 100% identity (1404/1404 bp) with previously deposited sequence (accession number CP068224) of S. multivorum FDAARGOS in GenBank. Based on the maximum likelihood method, phylogenetic analysis revealed 100% bootstrap support values with S. multivorum. Finally, the bacterium was identified as S. multivorum. This is the first report of S. multivorum causing bacterial rot of mushroom. The fruiting body of S. multivorum consists of multiple folded flat lobes, which are thin and have large surface area, may facilitate the infection of S. multivorum. Sphingobacterium sp. are named for their synthesize sphingolipids, which play an important role in bacterial infection (Kunz et al., 2019). These results will contribute to developing control strategies for this disease.
PubMed: 38587796
DOI: 10.1094/PDIS-01-24-0022-PDN -
The Journal of Biological Chemistry Mar 2024Serine palmitoyltransferase (SPT) catalyzes the pyridoxal-5'-phosphate (PLP)-dependent decarboxylative condensation of l-serine and palmitoyl-CoA to form...
Serine palmitoyltransferase (SPT) catalyzes the pyridoxal-5'-phosphate (PLP)-dependent decarboxylative condensation of l-serine and palmitoyl-CoA to form 3-ketodihydrosphingosine (KDS). Although SPT was shown to synthesize corresponding products from amino acids other than l-serine, it is still arguable whether SPT catalyzes the reaction with d-serine, which is a question of biological importance. Using high substrate and enzyme concentrations, KDS was detected after the incubation of SPT from Sphingobacterium multivorum with d-serine and palmitoyl-CoA. Furthermore, the KDS comprised equal amounts of 2S and 2R isomers. H-NMR study showed a slow hydrogen-deuterium exchange at Cα of serine mediated by SPT. We further confirmed that SPT catalyzed the racemization of serine. The rate of the KDS formation from d-serine was comparable to those for the α-hydrogen exchange and the racemization reaction. The structure of the d-serine-soaked crystal (1.65 Å resolution) showed a distinct electron density of the PLP-l-serine aldimine, interpreted as the racemized product trapped in the active site. The structure of the α-methyl-d-serine-soaked crystal (1.70 Å resolution) showed the PLP-α-methyl-d-serine aldimine, mimicking the d-serine-SPT complex prior to racemization. Based on these enzymological and structural analyses, the synthesis of KDS from d-serine was explained as the result of the slow racemization to l-serine, followed by the reaction with palmitoyl-CoA, and SPT would not catalyze the direct condensation between d-serine and palmitoyl-CoA. It was also shown that the S. multivorum SPT catalyzed the racemization of the product KDS, which would explain the presence of (2R)-KDS in the reaction products.
Topics: Catalytic Domain; Crystallization; Deuterium Exchange Measurement; Electrons; Hydrogen; Palmitoyl Coenzyme A; Serine; Serine C-Palmitoyltransferase; Sphingobacterium; Sphingosine; Stereoisomerism; Substrate Specificity
PubMed: 38325740
DOI: 10.1016/j.jbc.2024.105728 -
PLoS Pathogens Jan 2024Microbes associated with an organism can significantly modulate its susceptibility to viral infections, but our understanding of the influence of individual microbes...
Microbes associated with an organism can significantly modulate its susceptibility to viral infections, but our understanding of the influence of individual microbes remains limited. The nematode Caenorhabditis elegans is a model organism that in nature inhabits environments rich in bacteria. Here, we examine the impact of 71 naturally associated bacteria on C. elegans susceptibility to its only known natural virus, the Orsay virus. Our findings reveal that viral infection of C. elegans is significantly influenced by monobacterial environments. Compared to an Escherichia coli environmental reference, the majority of tested bacteria reduced C. elegans susceptibility to viral infection. This reduction is not caused by virion degradation or poor animal nutrition by the bacteria. The repression of viral infection by the bacterial strains Chryseobacterium JUb44 and Sphingobacterium BIGb0172 does not require the RIG-I homolog DRH-1, which is known to activate antiviral responses such as RNA interference and transcriptional regulation. Our research highlights the necessity of considering natural biotic environments in viral infection studies and opens the way future research on host-microbe-virus interactions.
Topics: Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; RNA Interference; Virus Diseases; Viruses
PubMed: 38232128
DOI: 10.1371/journal.ppat.1011947 -
Applied Microbiology and Biotechnology Dec 2024In recent years organic food is gaining popularity as it is believed to promote better human health and improve soil sustainability, but there are apprehensions about...
In recent years organic food is gaining popularity as it is believed to promote better human health and improve soil sustainability, but there are apprehensions about pathogens in organic produces. This study was designed to understand the effect of different composts and soils on the status of the microbiome present in organically grown leafy vegetables. 16S rRNA metagenomic profiling of the leaves was done, and data were analyzed. It was found that by adding composts, the OTU of the microbiome in the organic produce was higher than in the conventional produce. The beneficial genera identified across the samples included plant growth promoters (Achromobacter, Paenibacillus, Pseudomonas, Sphingobacterium) and probiotics (Lactobacillus), which were higher in the organic produce. Some pathogenic genera, viz., plant pathogenic bacteria (Cellvibrio, Georgenia) and human pathogenic bacteria (Corynebacterium, Acinetobacter, Streptococcus, Streptomyces) were also found but with relatively low counts in the organic produce. Thus, the present study highlights that organic produce has lesser pathogen contamination than the conventional produce. KEY POINTS: • 16S rRNA metagenomics profiling done for organic red amaranth cultivar • Microbial richness varied with respect to the soil and compost type used • The ratio of beneficial to pathogenic genera improves with the addition of compost.
Topics: Humans; Composting; RNA, Ribosomal, 16S; Soil; Bacteria; Metagenome
PubMed: 38229333
DOI: 10.1007/s00253-023-12982-7 -
Pathogens (Basel, Switzerland) Oct 2023This study was conducted to investigate the antagonistic potential of endophytic and rhizospheric bacterial isolates obtained from in suppressing and and promoting...
This study was conducted to investigate the antagonistic potential of endophytic and rhizospheric bacterial isolates obtained from in suppressing and and promoting the growth of cucumber. Molecular identification of bacterial strains associated with confirmed that these strains belong to the , , , , , , , , , and genera. A dual culture assay showed that nine of the bacterial strains exhibited antifungal activity, four of which were effective against both pathogens. Strains B27 () and B28 () caused the highest percentage of inhibition towards (48.5% and 48.1%, respectively). growth was impeded by the B21 (, 44.7%) and B28 (, 51.1%) strains. Scanning electron microscopy showed that the strains caused abnormality in phytopathogens' mycelia. All of the selected bacterial strains showed good IAA production (>500 ppm). A paper towel experiment demonstrated that these strains improved the seed germination, root/shoot growth, and vigor index of cucumber seedlings. Our findings suggest that the bacterial strains from are suppressive to and and can promote cucumber growth. This appears to be the first study to report the efficacy of these bacterial strains from against and .
PubMed: 38003740
DOI: 10.3390/pathogens12111275 -
ACS Omega Oct 2023The objective of this study was to investigate the impact of thermophilic bacteria on crude fiber content, carbohydrate-active enzyme (CAZyme) genes, and associated...
The objective of this study was to investigate the impact of thermophilic bacteria on crude fiber content, carbohydrate-active enzyme (CAZyme) genes, and associated microbial communities during Chinese medicine residues composting. The study examines changes over 15 days of composting with () and without (CK) thermophilic microbial agents. Results show that the group compost temperature reached a maximum of 71.0 °C and remained above 70 °C for 2 days, while the group CK maximum temperature was only 60.9 °C. On Day 15, the seed germination index (GI) of group reached 98.7%, while the group CK GI was only 56.7%. After composting, the degradation rates of cellulose, hemicellulose, and lignin in group increased by 5.1, 22.5, and 18.5%, respectively, compared to those in group CK. Thermophilic microbial agents changed the microbial communities related to CAZymes, increasing and abundance and reducing and abundance. Thermophilic microbial agents also increased the abundance of the GT4, GT2_Glycos_transf_2, and AA3 gene families. These results show that thermophilic microbial agents can increase composting temperature, accelerate compost maturation, and promote crude fiber degradation. Therefore, they have broad application potential.
PubMed: 37901486
DOI: 10.1021/acsomega.3c05442 -
Journal of Environmental Management Jan 2024Bioactive coatings are envisaged as a promising biotechnology to tackle the emerging problem of indoor air pollution. This solution could cope with the low...
Bioactive coatings are envisaged as a promising biotechnology to tackle the emerging problem of indoor air pollution. This solution could cope with the low concentrations, the wide range of compounds and the hydrophobicity of some indoor air VOCs, which are the most important bottlenecks regarding the implementation of conventional biotechnologies for indoor air treatment. A bioactive coating-based bioreactor was tested in this study for the abatement of different VOCs (n-hexane, toluene and α-pinene) at different empty bed residence times (EBRT) and inlet VOC concentrations. The performance of this reactor was compared with a conventional biofilm-based bioreactor operated with the same microbial inoculum. After an acclimation period, the bioactive coating-based bioreactor achieved abatements of over 50% for hexane, 80% for toluene and 70% for pinene at EBRTs of 112-56 s and inlet concentrations of 9-15 mg m. These results were about 25, 10 and 20% lower than the highest removals recorded in the biofilm-based bioreactor. Both bioreactors experienced a decrease in VOC abatement by ∼25% for hexane, 45% for toluene and 40% for pinene, after reducing the EBRT to 28 s. When inlet VOC concentrations were progressively reduced, VOC abatement efficiencies did not improve. This fact suggested that low EBRTs and low inlet VOCs concentration hindered indoor air pollutant abatement as a result of a limited mass transfer and bioavailability. Metagenomic analyses showed that process operation with toluene, hexane and pinene as the only carbon and energy sources favored an enriched bacterial community represented by the genera Devosia, Mesorhizobium, Sphingobacterium and Mycobacterium, regardless of the bioreactor configuration. Bioactive coatings were used in this work as packing material of a conventional bioreactor, achieving satisfactory VOC abatement similar to a conventional bioreactor.
Topics: Air Pollution, Indoor; Hexanes; Volatile Organic Compounds; Air Pollutants; Bioreactors; Toluene; Filtration
PubMed: 37897901
DOI: 10.1016/j.jenvman.2023.119362