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Phosphate materials (PMs) combine with phosphate solubilizing bacteria play an essential roles in lead (Pb) immobilization, but their resulting ability to reduce Pb bioavailability may vary depending on PMs used. In this study, Pseudomonas edaphica GAU-665 and three PMs: tricalcium phosphate, calcium phytate and nano-hydroxyapatite were respectively encapsulated into bio-beads by sodium alginate, which immobilization efficiency of Pb2+ were 99.11%, 97.76% and 99.02% at initial Pb2+ concentration of 200 mg L-1, respectively. The Pb2+ immobilization performance of bio-beads under different conditions and their organic acids secreted were examined. Most Pb2+ was immobilized by bio-beads through combined functions of adsorption, precipitation, ion exchange and biomineralization, accompanied by the formation of more stable compounds such as Pb3(PO4)2, Pb5(PO4)3OH and Pb5(PO4)3Cl. Meanwhile, pot experimental results indicated that the inoculation of CPhy (calcium phytate) bio-beads with PSB have highest biomass and root growth of oat (Avena sativa L.) in Pb-stressed compared with CK, which increased the content of chlorophyll b (167.51%) in shoot. In addition, the CPhy bio-beads enhance the peroxidase, catalase activities and reduce the malondialdehyde content to alleviating lead physiological toxicity in oat, which reductions the Pb accumulation in shoot (52.06%) and root (81.04%), and increased the residual fraction of Pb by 165.80% in soil. These findings suggest the bio-beads combined with P. edaphica GAU-665 and calcium phytate is an efficient Pb immobilization material and provided feasible way to improve safety agricultural production and Pb-contaminated soil remediation.
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Fosfatos , Poluentes do Solo , Chumbo , Pseudomonas , Ácido Fítico , Solo , Poluentes do Solo/análiseRESUMO
Diplothylacus sinensis is reported as an intriguing parasitic barnacle that can negatively affect the growth, molting, reproduction in several commercially important portunid crabs. To better understand the molecular mechanisms of host-parasite interactions, we characterized the gene expression profiles from the healthy and D. sinensis infected Portunus sanguinolentus by high-through sequence method. Totally, the transcriptomic analysis generated 52, 266, 600 and 51, 629, 604 high quality reads from the infected and control groups, respectively. The clean reads were assembled to 90,740 and 69,314 unigenes, with the average length of 760 bp and 709 bp, respectively. The expression analysis showed that 18,959 genes were significantly changed by the parasitism of D. sinensis, including 4769 activated genes and 14,190 suppressed genes. The differentially expressed genes were categorized into 258 KEGG pathways and 647 GO terms. The GO analysis mapped 13 DEGs related to immune system process and 32 DEGs related to immune response, respectively, suggesting a potential alteration of transcriptional expression patterns in complement cascades of P. sanguinolentus. Additionally, 4 representative molting-related genes were down-regulated in parasitized group, indicating D. sinensis infection appeared to suppress the producing of ecdysteroid hormones. In conclusion, the present study improves our understanding on parasite-host interaction mechanisms, which focuses the function of Ecdysone receptor, Toll-like receptor and cytokine receptor of crustacean crabs infestation with rhizocephalan parasites.
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Braquiúros , Parasitos , Thoracica , Animais , Braquiúros/genética , Ecdisona , Ecdisteroides , Perfilação da Expressão Gênica , Masculino , Receptores de Citocinas/genética , Natação , Thoracica/genética , TranscriptomaRESUMO
Ammonia nitrogen, a major oxygen-consuming pollutant in the environment, can adversely affect aquatic organisms such as fish, bivalves, and crustaceans. We investigated the toxic effects of ammonia nitrogen on the Hong Kong oyster, Crassostrea hongkongensis, using flow cytometry and 1H nuclear magnetic resonance metabolomics. Exposure to ammonia nitrogen caused time- and concentration-dependent alterations in various immune parameters in hemocytes and impaired the metabolic profiles of the gills. We observed changes in the rate of apoptosis, esterase activity, lysosomal mass, hemocyte counts, phagocytic activity, and mitochondrial mass. Exposure affected metabolic pathways involved in energy metabolism, osmotic balance, and oxidative stress. We concluded that ammonia nitrogen induces metabolic and hematological dysfunction in C. hongkongensis, and our findings provide insights into the biochemical defense strategies of bivalves exposed to acute high-concentration ammonia nitrogen.
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Crassostrea , Amônia/metabolismo , Amônia/toxicidade , Animais , Hemócitos/metabolismo , Hong Kong , Nitrogênio/metabolismoRESUMO
The study of the rhizosphere microbial community in salinized soils aids in the elucidation of new and important microbial functional groups, which is of great importance in vegetation restoration and ecological reconstruction of salinized soil. The rhizosphere soil bacterial diversity and community structures of four halophytes, including Kalidium foliatum, Lycium ruthenicum, Karelinia caspia and Phragmites australis, typically distributed in the saline-alkaline land of Southern Xinjiang, China, were studied using an Illumina paired-end sequence platform. The study aims to reveal the alpha diversity, species composition, abundance and the differences of rhizosphere bacteria among the four halophytes, explore their correlation with environmental factors. The results showed that the highest bacterial species diversity was associated with P. communis, followed by K. foliatum, K. caspia, and L. ruthenicum. The species richness was the lowest for L. ruthenicum, while the others showed no significant difference. Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes were the most dominant phyla. And Bacillus and Halomonas were the most common dominant genera. The bacterial communities associated with K. foliatum and K. caspia were similar, while that of L. ruthenicum was significantly different from other halophytes. Soil total nitrogen and total phosphorus, soil organic matter, soil water content, electronic conductivity and pH were identified as the key factors affecting bacterial abundance associated with the assayed halophytes. These results indicate that the four halophytes evaluated in the present study have a similar rhizosphere bacterial community structure due to their being in the same region. However, the bacterial abundance is different among the plant species, and soil properties are the important factors driving the structures of bacterial communities.
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Rizosfera , Plantas Tolerantes a Sal , Bactérias/genética , China , Solo , Microbiologia do SoloRESUMO
Grasslands are among the most widespread environments on Earth, yet we still have poor knowledge of their microbial-mediated carbon cycling in the context of human activity and climate change. We conducted a systematic bibliometric analysis of 1,660 literature focusing on microbial-mediated grassland carbon cycling in the Scopus database from 1990 to 2022. We observed a steep increase in the number of multidisciplinary and interdisciplinary studies since the 2000s, with focus areas on the top 10 subject categories, especially in Agricultural and Biological Sciences. Additionally, the USA, Australia, Germany, the United Kingdom, China, and Austria exhibited high levels of productivity. We revealed that the eight papers have been pivotal in shaping future research in this field, and the main research topics concentrate on microbial respiration, interaction relationships, microbial biomass carbon, methane oxidation, and high-throughput sequencing. We further highlight that the new research hotspots in microbial-mediated grassland carbon cycling are mainly focused on the keywords "carbon use efficiency," "enzyme activity," "microbial community," and "high throughput sequencing." Our bibliometric analysis in the past three decades has provided insights into a multidisciplinary and evolving field of microbial-mediated grassland carbon cycling, not merely summarizing the literature but also critically identifying research hotspots and trends, the intellectual base, and interconnections within the existing body of collective knowledge and signposting the path for future research directions.
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Heavy metals in soil, water, and industrial production can affect the antibiotic resistance of bacteria. Antibiotic resistance in gut microbiota has been extensively researched. The effects of cadmium (Cd) was investigated on the gut microbiota and antibiotic resistance genes (ARGs) of Haliotis diversicolor, a commercially important abalone species. By exposing H. diversicolor to four concentrations of Cd (0 µg L-1 (control), 6.5 µg L-1 (low), 42.25 µg L-1 (medium), and 274.63 µg L-1 (high)) for 30 and 60 days, 16 types of ARG (aadA-01, aadA-02, cfr, dfrA1, ermB, floR, folA, mecA, sul2, tetB-01, tetC-01, tetD-01, tetG-01, tetM-02, tetQ, vanC-01), and 1213 genus and 27 phylum microbiomes were detected. ARGs can be resistant to aminoglycoside, beta-lactamase, macrolide-lincosamide-streptogramin B, multidrug, florfenicol, macrolide, sulfonamides, tetracyclines, and vancomycin. Cadmium exposure significantly alters the abundance of tetC-01, tetB-01, tetQ, sul2, and aadA-01. About 5% (61) of genus-level microorganisms were significantly affected by Cd exposure. Microbiota alpha and beta diversities in the 60-day 42.25 µg L-1 Cd treatment differed significantly from those in other treatments. In addition, 26 pathogens were detected, and two pathogens (Vibrio and Legionella) were significantly affected by Cd exposure. Significant correlations between pathogens and ARGs increased with increased Cd concentration after 60 days of Cd exposure. Cadmium exposure may cause gut microbiota disturbance in H. diversicolor and increase the likelihood of ARG transfer to pathogens, increasing potential ecological and economic risks.
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Antibacterianos , Microbioma Gastrointestinal , Antibacterianos/farmacologia , Cádmio/toxicidade , Genes Bacterianos , Microbioma Gastrointestinal/genética , Resistência Microbiana a Medicamentos/genética , MacrolídeosRESUMO
Microbial deodorization is a novel strategy for reducing odor in livestock and poultry feces. Herein, 12 strains of ammonia (NH3) and 15 hydrogen sulfide (H2S) removing bacteria were obtained with a removal efficiency of 65.20-79.80% and 34.90-79.70%, respectively. A novel bacteria deodorant named MIX (Bacillus zhangzhouensis, Bacillus altitudinis, and Acinetobacter pittii at a ratio of 1:1:2) were obtained. MIX can shorten the temperature rising stage by 2 days and prolong the thermophilic stage by 4 days. The ability of MIX to remove NH3, H2S, and volatile fatty acids (VFAs) and the underlying removal mechanism were analyzed during pig feces fermentation. MIX can significantly reduce the concentrations of NH3 and H2S by 41.82% and 66.35% and increase the concentrations of NO3--N and SO42- by 7.80% and 8.83% (P < 0.05), respectively, on the 25th day. Moreover, the concentrations of acetic, propionate, iso-valerate, and valerate were significantly reduced. The dominant bacteria communities at the phylum level were Firmicutes, Proteobacteria, Bacteroidetes, and Spirochaetes. B. zhangzhouensis and B. altitudinis could convert NH4+-N to NO3--N, and A. pittii could transfer H2S to SO42-. This study revealed that bacteria deodorant can reduce the concentrations of NH3, H2S, and VFAs in pig feces and increase those of NH4+, NO3-, and SO42- and has excellent potential in deodorizing livestock and poultry feces composting.
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Desodorantes , Sulfeto de Hidrogênio , Suínos , Animais , Fermentação , Fezes , Amônia , Bactérias , Ácidos Graxos Voláteis , ValeratosRESUMO
Triploid Fujian oyster (Crassostrea angulata) is crucial to aquaculture and coastal ecosystems because of its accelerated growth and heightened resilience against environmental stressors. In light of the increasing prevalence of nanoplastic pollution in the ocean, understanding its potential impact on this organism, particularly its adaptive responses, is of paramount importance. Despite this, the effects of nanoplastic pollution on the physiology of C. angulata remain largely unexplored. In this study, we explored the responses of triploid Fujian oysters to nanoplastic stress during a 14-day exposure period, employing an integrative methodology that included physiological, metabolomic, and 16S rRNA sequencing analyses. Our results demonstrate that the oysters exhibit a strong adaptive response to nanoplastic exposure, characterized by alterations in enzyme activity, metabolic pathways, and microbial community composition, indicative of an adaptive recovery state as opposed to a disordered state. Oysters subjected to elevated nanoplastic levels exhibited adaptive responses primarily by boosting the activity of the antioxidant enzyme catalase and elevating the levels of antioxidants such as adenosine, 3-(4-hydroxyphenyl)pyruvate, D-sorbitol, d-mannose, and unsaturated fatty acids, as well as the functional amino acids l-proline and l-lysine. Nanoplastic treatment also resulted in increased activity of succinate dehydrogenase, a key component of energy metabolism, and increased contents of intermediate metabolites or products of energy metabolism, such as adenosine monophosphate, adenosine, guanosine, creatine, and thiamine. Nanoplastic treatment led to an increase in the abundance of certain advantageous genera of gut bacteria, specifically Phaeobacter and Nautella. The observed adaptive response of triploid Fujian oysters to nanoplastic stress provides valuable insights into the mechanisms underpinning resilience in marine bivalves.
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Crassostrea , Animais , Crassostrea/genética , Microplásticos , Triploidia , Ecossistema , RNA Ribossômico 16S/genética , Adenosina , AntioxidantesRESUMO
Exopolysaccharides (EPS) are macromolecular substances with environmentally beneficial properties. At present, some reports have focused on the effects of EPS on plants salt stress; however, few studies have carried out a deeper characterization of the EPS components involved in Na+ binding. We investigated the mechanism of Na+ adsorption by Pseudomonas simiae MHR6 EPS and the regulation of ion homeostasis in maize under salt stress. The results showed that NaCl at 6% significantly inhibited MHR6 growth but enhanced EPS secretion. The chemical composition of the EPS varied in response to an increased NaCl concentration, and the proportion of polysaccharides was consistently higher than that of proteins. The highest Na+ adsorption was observed for 6% NaCl. The FTIR, SEM, and EDX results further indicated that EPS effectively biosorbed Na+. Furthermore, adding EPS improved Na+/K+ homeostasis in maize under salt stress. These results suggest that MHR6 EPS has potential for future development and utilization as a plant growth biostimulant in saline-alkali land.
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Estresse Fisiológico , Zea mays , Zea mays/metabolismo , Adsorção , Cloreto de Sódio/farmacologia , Estresse Salino , Íons , Sódio/metabolismo , Homeostase , Potássio/metabolismoRESUMO
Zinc Oxide nanoparticles (ZnO NPs), due to their ubiquitous use in industrial and consumer applications, present potential risks to marine ecosystems and biota, especially oysters. The physiological and immunological health of marine species is highly dependent on salinity levels. However, the combined impact of lowered salinity and exposure to ZnO NPs, particularly on key marine species like oysters, is an area that requires more research. Our study aimed to examine these concurrent stressors' impacts on phenotypic markers, gill and hepatopancreas physiological indices, and hemocyte immune parameters of Crassostrea hongkongensis. We subjected six oyster cohorts to varied ZnO NPs concentrations and salinity levels over 21 days. Our findings reveal that individual exposure to ZnO NPs or diminished salinity disrupts oyster physiology, impacting metabolism, antioxidant capacity, immune response, and energy distribution through distinct mechanisms. Remarkably, low salinity constituted a more significant threat than isolated ZnO NPs. However, when confronted with combined stressors, oysters exhibited a compensatory response, attenuating individual stressors' detrimental effects. This adaptation was characterised by reduced apoptosis rates, increased calcium ion concentration in mature hemocytes, and a restoration of conditioned indices, hepatopancreas alkaline phosphatase, and gill catalase activity to baseline levels. Principal Component Analysis and Integrated Biomarker Responses validated this compensatory phenomenon. Partial Least Squares Pathway Model analysis underscored these stressors' profound implications on oyster health, primarily driven by stressor exposure rather than mere zinc concentrations, despite acknowledging zinc's immunosuppressive impact on oyster immunity. Our research emphasises the importance of assessing multiple stressors' cumulative effects on aquatic species' ecological resilience, accentuating the need for comprehensive analyses incorporating functional specificity among diverse organs and immune components, including gill, hepatopancreas, and the critical hemocytes.
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Crassostrea , Nanopartículas , Óxido de Zinco , Animais , Óxido de Zinco/toxicidade , Óxido de Zinco/metabolismo , Hong Kong , Salinidade , Ecossistema , Crassostrea/fisiologia , Antioxidantes/metabolismo , Zinco/metabolismo , HemócitosRESUMO
In order to develop environment friendly microbial inhibitor that can also control disease and promote oat (Avena sativa) growth, the growth rate method and response surface methodology were used to screen wetting agents, preservatives and protective agents at optimal concentrations in this study. Antagonistic activity of the tested bacterium and cell-free fermentation liquid against pathogenic fungi was evaluated on potato dextrose agar (PDA) substratum plates by dual culture technique. Oxford cup method was used to measure antagonistic reaction between screened bacteria. According to each screened bacteria with 50 mL were mixed and cultured in Luria-bertani (LB) substratum. Additives of Wetting agents, UV-protectors, and preservatives were screened by single factor test on the growth concentration of screened mixed bacteria. Afterwards, the optimal additives and concentrations were screened by Box-Behnken method. The microbial inhibitor was detected according to national standards GB20287-2006 and tested on oat in a pot experiment. The results showed that: (1) Functional bacteria which including Bacillus velezensis and Brevundimonas faecalis had control effects of 50.00% to 83.29% on three pathogenic fungi, and their cell free-fermentation liquid could inhibit the growth of pathogenic fungi from 23.51% to 39.90%; (2) Tween-80 was most suitable as wetting agents for Mix biocontrol bacteria (MBB) with 1.00% mass fraction; Sorbitol was selected as UV protective agents for MBB with 0.50% mass fraction. And methyl paraben was used as a preservative for MBB, with 0.50% mass fraction; (3) The most effective adjuvant contained 14.96 mL/L Tween-80, 5.12 g/L methylparaben and 5.6 g/L sorbitol; and (4) The microbial inhibitor controlled 45.57% of oat root rot and increased plant height, root length and seedling biomass. This study provides a suitable environment for the protection of mixed biocontrol bacteria, and lays a foundation for the prevention and control of oat diseases, the promotion of growth and the improvement of quality.
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[This corrects the article DOI: 10.3389/fmicb.2022.1019383.].
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This study employed solution crystallization in food engineering to prepare a high-purity vitamin intermediate, optimize its crystal morphology and regulate its particle size distribution. Model analysis was performed to investigate the quantitative correlations between the process variables and target parameters, indicating the substantial effect of temperature on separation performance. Under optimal conditions, the product purity exceeded 99.5%, which meets the requirement of the subsequent synthesis process. A high crystallization temperature reduced the agglomeration phenomenon and increased particle liquidity. Herein, we also proposed a temperature cycling strategy and a gassing crystallization routine to optimize the particle size. The results illustrated that the synergistic control of temperature and gassing crystallization could substantially improve the separation process. Overall, based on a high separation efficiency, this study combined model analysis and process intensification pathways to explore the process parameters on product properties such as purity, crystal morphology, and particle size distribution.
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Cristalização , Cristalização/métodos , Tamanho da Partícula , Temperatura , AlimentosRESUMO
BACKGROUND: Viruses play critical roles in the marine environment because of their interactions with an extremely broad range of potential hosts. Many studies of viruses in seawater have been published, but viruses that inhabit marine animals have been largely neglected. Oysters are keystone species in coastal ecosystems, yet as filter-feeding bivalves with very large roosting numbers and species co-habitation, it is not clear what role they play in marine virus transmission and coastal microbiome regulation. RESULTS: Here, we report a Dataset of Oyster Virome (DOV) that contains 728,784 nonredundant viral operational taxonomic unit contigs (≥ 800 bp) and 3473 high-quality viral genomes, enabling the first comprehensive overview of both DNA and RNA viral communities in the oyster Crassostrea hongkongensis. We discovered tremendous diversity among novel viruses that inhabit this oyster using multiple approaches, including reads recruitment, viral operational taxonomic units, and high-quality virus genomes. Our results show that these viruses are very different from viruses in the oceans or other habitats. In particular, the high diversity of novel circoviruses that we found in the oysters indicates that oysters may be potential hotspots for circoviruses. Notably, the viruses that were enriched in oysters are not random but are well-organized communities that can respond to changes in the health state of the host and the external environment at both compositional and functional levels. CONCLUSIONS: In this study, we generated a first "knowledge landscape" of the oyster virome, which has increased the number of known oyster-related viruses by tens of thousands. Our results suggest that oysters provide a unique habitat that is different from that of seawater, and highlight the importance of filter-feeding bivalves for marine virus exploration as well as their essential but still invisible roles in regulating marine ecosystems. Video Abstract.
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Crassostrea , Microbiota , Vírus , Animais , Crassostrea/genética , DNA , Água do Mar , Vírus/genéticaRESUMO
Gender differences in the hemocyte immune response of Hong Kong oyster Crassostrea hongkongensis to Vibrio harveyi and lipopolysaccharide (LPS) infection exist. To determine if a gender difference also exists, we use a 1H NMR-based metabolomics method to investigate responses in C. hongkongensis hepatopancreas tissues to V. harveyi and LPS infection. Both infections induced pronounced gender- and immune-specific metabolic responses in hepatopancreas tissues. Responses are mainly presented in changes in substances involved in energy metabolism (decreased glucose, ATP, and AMP in males and increased ATP and AMP in LPS-infected females), oxidative stress (decreased glutathione in males and decreased tryptophan and phenylalanine and increased choline and proline in LPS-infected females), tricarboxylic acid (TCA) cycle (decreased α-ketoglutarate acid and increased fumarate in LPS-infected males, and decreased fumarate in LPS-infected females), and osmotic regulation (decreased trigonelline and increased taurine in V. harveyi-infected males and decreased betaine in V. harveyi-infected females). Results suggest that post-spawning-phase male oysters have a more significant energy metabolic response and greater ability to cope with oxidative stress than female oysters. We propose that the impact of oyster gender should be taken into consideration in the aftermath of oyster farming or oyster disease in natural seas.
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The use of plant growth promoting bacteria (PGPB) express phytase (myo-inositol hexakisphosphate phosphohydrolase) capable of hydrolyzing inositol phosphate in soil was a sustainable approach to supply available phosphorus (P) to plants. A total of 73 bacterial isolates with extracellular phytase activity were selected from seven dominant grass species rhizosphere in alpine grassland of Qinghai-Tibetan Plateau. Then, the plant growth promoting (PGP) traits of candidate bacteria were screened by qualitative and quantitative methods, including organic/inorganic Phosphorus solubilization (P. solubilization), plant hormones (PHs) production, nitrogen fixation, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity and antimicrobial activity. Further experiment were conducted to test their growth promoting effect on Lolium perenne L. under P-limitation. Our results indicated that these bacteria as members of phyla Proteobacteria (90.41%) and Actinobacteria (9.59%) were related to 16 different genera. The isolates of Pseudomonas species showed the highest isolates number (36) and average values of phytase activity (0.267 ± 0.012 U mL-1), and showed a multiple of PGP traits, which was a great candidate for PGPBs. In addition, six strains were positive in phytase gene (ß-propeller phytase, bpp) amplification, which significantly increased the shoot length, shoot/root fresh weight, root average diameter and root system phytase activity of Lolium perenne L. under P-limitation, and the expression of phytase gene (bppP) in root system were verified by qPCR. Finally, the PHY101 gene encoding phytase from Pseudomonas mandelii GS10-1 was cloned, sequenced, and recombinantly expressed in Escherichia coli. Biochemical characterization demonstrated that the recombinant phytase PHY101 revealed the highest activity at pH 6 and 40°C temperature. In particular, more than 60% of activity was retained at a low temperature of 15°C. This study demonstrates the opportunity for commercialization of the phytase-producing PGPB to developing localized microbial inoculants and engineering rhizobacteria for sustainable use in alpine grasslands.
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In the process of microbial degradation of pyrethroid pesticides, the synergistic effect of the microbial community is more conducive to the complete degradation of toxic compounds than a single strain. At present, the degradation pathway of pyrethroids in a single strain has been well revealed, but the synergistic metabolism at the community level has not been well explained. This study elucidated the bacterial community succession, metabolic pathway, and phytotoxicity assessment during ß-cyfluthrin biodegradation by a novel bacterial consortium enriched from contaminated soil. The results showed that the half-life of ß-cyfluthrin at different initial concentrations of 0.25, 0.5, 0.75, and 1.0 mg mL-1 were 4.16, 7.34, 12.81, and 22.73 days, respectively. Enterobacter was involved in ß-cyfluthrin degradation metabolism in the initial stage, and other bacterial genera (Microbacterium, Ochrobactrum, Pseudomonas, Hyphomicrobiaceae, Achromobacter, etc.) significantly contribute to the degradation of intermediate metabolites in the later stages. Functional gene prediction and metabolite analysis showed that xenobiotic biodegradation and metabolism, especially benzoate degradation and metabolism by cytochrome P450 were the major means of ß-cyfluthrin degradation. Further, two degradation pathways of ß-cyfluthrin were proposed, which were mainly ester hydrolysis and oxidation to degrade ß-cyfluthrin through the production of carboxylesterase and oxidoreductase. In addition, the inoculated bacterial consortium could degrade ß-cyfluthrin residues in water and soil and reduce its phytotoxicity in Medicago sativa. Hence, this novel bacterial consortium has important application in the remediation environments polluted by ß-cyfluthrin.
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Piretrinas , Bactérias/genética , Bactérias/metabolismo , Biodegradação Ambiental , Nitrilas/química , Piretrinas/química , SoloRESUMO
Antimicrobial resistance genes (ARGs) pose a serious threat to environment and human health. However, few studies address the abundance and distribution of ARGs associated with farmed fish and their aquaculture environment. Here we conducted an analysis of the abundance and distribution of gut and gill ARGs by quantitative PCR techniques associated with the spotted sea bass (Lateolabrax maculatus) as well as the bacterial communities in the surrounding environment (water and sediment). For this purpose, we sampled six aquaculture ponds in Zhuhai, Guangdong Province, the largest spotted sea bass cultivation site in China. Predominant ARGs were floR, sul2, and tetM-01 in the gut and tetQ, sul1, and floR in the gills. The copy numbers of sul1, sul2, and cmlA1-01 were significantly higher in the environment. Moreover, significant differences were found among the microbiota of the gut, gills, and environment. The former was more similar to those of the environmental microbial communities compared with other sources. The fish gut and gill microbiota were predominantly populated by Fusobacteria and Actinobacteria, respectively. In contrast, Proteobacteria were dominant in water and sediment. Correlation analysis showed that Fusobacteria and Actinobacteria positively correlated with floR and tetQ, respectively, indicating that these microbes were potential hosts for ARGs. Our results showed that ARGs in farmed fish showed marked difference with their aquaculture environment, thus providing a valuable reference for identifying deleterious ARGs in aquatic fish.
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Bass , Microbiota , Animais , Antibacterianos/farmacologia , Aquicultura , China , Farmacorresistência Bacteriana , Genes Bacterianos , Humanos , LagoasRESUMO
Contrary to the early evidence, which indicated that the mitochondrial architecture in one of the two major annelida clades, Sedentaria, is relatively conserved, a handful of relatively recent studies found evidence that some species exhibit elevated rates of mitochondrial architecture evolution. We sequenced complete mitogenomes belonging to two congeneric shell-boring Spionidae species that cause considerable economic losses in the commercial marine mollusk aquaculture: Polydora brevipalpa and Polydora websteri. The two mitogenomes exhibited very similar architecture. In comparison to other sedentarians, they exhibited some standard features, including all genes encoded on the same strand, uncommon but not unique duplicated trnM gene, as well as a number of unique features. Their comparatively large size (17,673 bp) can be attributed to four non-coding regions larger than 500 bp. We identified an unusually large (putative) overlap of 14 bases between nad2 and cox1 genes in both species. Importantly, the two species exhibited completely rearranged gene orders in comparison to all other available mitogenomes. Along with Serpulidae and Sabellidae, Polydora is the third identified sedentarian lineage that exhibits disproportionally elevated rates of mitogenomic architecture rearrangements. Selection analyses indicate that these three lineages also exhibited relaxed purifying selection pressures.
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Anelídeos/genética , Evolução Molecular , Ordem dos Genes , Genoma Mitocondrial , Mitocôndrias/genética , Filogenia , AnimaisRESUMO
In recent years, more and more studies have shown that early pathogenic bacterial infection in invertebrates can enhance immunity and significantly reduce mortality when reinfected with the same pathogen. There are mechanisms to explain this phenomenon, but they are relatively few. In addition, dose-dependent primary infection is also associated with increased immunity. In the present study, the initial infection dose and mortality of abalone Haliotis diversicolor after reinfection with Vibrio harveyi were recorded, and the mechanism of immune enhancement was investigated by the transcriptomic response of abalone after two successive stimuli with V. harveyi. Priming with different concentrations of pathogen can enhance immunity; however, higher concentration is not always better. Compared with the first exposure, more genes were up-regulated after the second exposure. Among the commonly expressed genes, the immune related genes were significantly or persistently highly expressed after two infections and included pattern recognition receptors as well as immune effectors, such as toll-like receptors, perlucin 4, scavenger receptor class B-like protein, cytochrome P450 1B1-like, glutathione S-transferase 6, lysozyme and so on; in addition, these immune-related genes were mainly distributed in the pathways related to phagocytosis and calcium signaling. Among the specifically expressed genes, compared with the first infection, more genes were involved in the immune, metabolic and digestive pathways after the second infection, which would be more conducive to preventing the invasion of pathogens. This study outlined the mechanism of immune enhancement in abalone after secondary infection at the global molecular level, which is helpful for a comprehensive understanding of the mechanism of immune priming in invertebrates.