RESUMO
Hydrogels with novel antimicrobial properties and accelerated wound healing are of great interest in the field of wound dressings because they not only prevent bacterial infections but also fulfill the essential needs of wound healing. In this study, multifunctional hydrogel dressings consisting of black phosphorus nanosheets(BPNS) surface-modified Zinc oxide (BP@ZnO heterojunction) based on gelatin (Gel), sodium alginate (SA), glutamine transferase (mTG), and calcium ions with a three-dimensional crosslinked network were prepared. The BP@ZnO-Gel/SA hydrogel has excellent mechanical properties, hemocompatibility (hemolysis rate: 3.29 %), swelling rate(832.8 ± 19.2 %), cytocompatibility, photothermal and photodynamic antibacterial properties(Sterilization rate: 96.4 ± 3.3 %). In addition, the hydrogel accelerates wound healing by promoting cell migration, immune regulation and angiogenesis. Thus, this hydrogel achieves the triple effect of antimicrobial, immunomodulation and angiogenesis, and is a tissue engineering strategy with great potential.
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Alginatos , Antibacterianos , Gelatina , Hidrogéis , Neovascularização Fisiológica , Fósforo , Cicatrização , Óxido de Zinco , Alginatos/química , Alginatos/farmacologia , Óxido de Zinco/química , Óxido de Zinco/farmacologia , Cicatrização/efeitos dos fármacos , Gelatina/química , Antibacterianos/farmacologia , Antibacterianos/química , Hidrogéis/química , Hidrogéis/farmacologia , Fósforo/química , Animais , Neovascularização Fisiológica/efeitos dos fármacos , Camundongos , Fatores Imunológicos/farmacologia , Fatores Imunológicos/química , Humanos , Pele/efeitos dos fármacosRESUMO
OBJECTIVE: This study investigates the relationship between hukou conversion and the psychological integration of rural older migrants, exploring the mediating role of accessibility to health resources. METHODS: The 3,963 valid samples of rural older migrants included in the study were sourced from the 2017 China Migrants Dynamic Survey (CMDS). The study established a multiple linear regression model for estimation and utilized inverse probability-weighted regression adjustment (IPWRA) method to correct for the selection bias of hukou conversion. RESULTS: Compared to older migrants with rural hukou, merit-based (ß = 0.384, 95% CI: 0.265 to 0.504), family-based (ß = 0.371, 95% CI: 0.178 to 0.565) and policy-based (ß = 0.306, 95% CI: 0.124 to 0.487) converters have significantly higher psychological integration. These findings remain robust even after addressing the potential issue of endogenous selection bias using the IPWRA method. Bootstrap mediating effect tests indicate that hukou conversion can indirectly affect psychological integration through the mediator role of health resources accessibility. CONCLUSION: Accessibility of health resources mediates the association between hukou conversion and psychological integration. Policymakers should enhance the implementation of hukou conversion, strengthen the health resource guarantee system, and achieve a deeper psychological integration among rural older migrants.
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Acessibilidade aos Serviços de Saúde , População Rural , Migrantes , Humanos , Masculino , Idoso , Feminino , Migrantes/psicologia , China/epidemiologia , Pessoa de Meia-Idade , Recursos em SaúdeRESUMO
For decades, titanium implants have shown impressive advantages in bone repair. However, the preparation of implants with excellent antimicrobial properties as well as better osseointegration ability remains difficult for clinical application. In this study, black phosphorus nanosheets (BPNSs) were doped into hydroxyapatite (HA) coatings using electrophoretic deposition. The coatings' surface morphology, roughness, water contact angle, photothermal properties, and antibacterial properties were investigated. The BP/HA coating exhibited a surface roughness of 59.1 nm, providing an ideal substrate for cell attachment and growth. The water contact angle on the BP/HA coating was measured to be approximately 8.55°, indicating its hydrophilic nature. The BPNSs demonstrated efficient photothermal conversion, with a temperature increase of 42.2°C under laser irradiation. The BP/HA composite coating exhibited a significant reduction in bacterial growth, with inhibition rates of 95.6% and 96.1% against Staphylococcus aureus and Escherichia coli. In addition, the cytocompatibility of the composite coating was evaluated by cell adhesion, CCK8 and AM/PI staining; the effect of the composite coating in promoting angiogenesis was assessed by scratch assay, transwell assay, and protein blotting; and the osteoinductivity of the composite coating was evaluated by alkaline phosphatase assay, alizarin red staining, and Western blot. The results showed that the BP/HA composite coating exhibited superior performance in promoting biological functions such as cell proliferation and adhesion, antibacterial activity, osteogenic differentiation, and angiogenesis, and had potential applications in vascularized bone regeneration.
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Durapatita , Titânio , Durapatita/farmacologia , Durapatita/química , Titânio/farmacologia , Titânio/química , Osseointegração , Osteogênese , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Revestidos Biocompatíveis/química , Antibacterianos/farmacologia , Água/farmacologia , Propriedades de SuperfícieRESUMO
PURPOSE: This study aimed to examine associations between the employment of older people and mental health across demographic characteristics, socioeconomic conditions, and health status, with a focus on pensions. METHODS: This study included 4,512 participants aged 60-69 from the CLASS in 2014. A multiple linear regression was conducted to investigate the association between employment and mental health. A causal forest model was applied to estimate the heterogeneous treatment effects. RESULTS: Employed individuals (n = 1,295) reported better mental health than their non-employed counterparts. This association displayed significant heterogeneity, primarily attributed to pensions. Those with lower pensions may be compelled to work due to financial reasons, thus offsetting the health-promotion effect of employment. CONCLUSION: Employment may benefit the mental health of older adults, which has a more significant marginal effect on those who are men, older, urban residents, without a spouse, below primary education, receiving more pensions, and less family and friend support.
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Emprego , Saúde Mental , Masculino , Humanos , Idoso , Feminino , Emprego/psicologia , Nível de Saúde , Escolaridade , ChinaRESUMO
Titanium and its alloys have found extensive use in the biomedical field, however, implant loosening due to weak osseointegration remains a concern. Improved surface morphology and chemical composition can enhance the osseointegration of the implant. Bioactive molecules have been utilized to modify the surface of the titanium-based material to achieve rapid and efficient osseointegration between the implant and bone tissues. In this study, the bioactive substance MC3T3-E1 protein-gelatin polyelectrolyte multilayers were constructed on the surface of the titanium implants by means of layer-by-layer self-assembly to enhance the strength of the bond between the bone tissue and the implant. The findings of the study indicate that the layer-by-layer self-assembly technique can enhance surface roughness and hydrophilicity to a considerable extent. Compared to pure titanium, the hydrophilicity of TiOH LBL was significantly increased with a water contact angle of 75.0 ± $$ \pm $$ 2.4°. The modified titanium implant exhibits superior biocompatibility and wound healing ability upon co-culture with cells. MC3T3-E1 cells were co-cultured with TiOH LBL for 1, 3, and 5 days and their viability was higher than 85%. In addition, the wound healing results demonstrate that TiOH LBL exhibited the highest migratory ability (243 ± 10 µm). Furthermore, after 7 days of osteogenic induction, the modified titanium implant significantly promotes osteoblast differentiation.
Assuntos
Osseointegração , Titânio , Polieletrólitos , Titânio/farmacologia , Titânio/química , Gelatina/farmacologia , Próteses e Implantes , Osteogênese , Propriedades de SuperfícieRESUMO
Skin wound healing will become a pressing and difficult problem following injury to the skin structure. Persistent wounds, in particular, become more vulnerable to bacterial infections, which can contribute to persistent skin inflammation. Therefore, it is critical to create a wound dressing that promotes wound healing while also being antimicrobial. In the present work, a multifunctional biological activity hydrogel formed by enzymatic cross-linking was developed by introducing graphene oxide (GO) and lactoferrin to gelatin hydrogel. Furthermore, by incorporating lactoferrin, the composite hydrogels exhibit excellent in vitro antibacterial and biocompatibility. According to cell experiments, the LTF-GO/Gel hydrogel can improve wound healing by enhancing L929 cell migration. Interestingly, under near-infrared light, LTF-GO/Gel hydrogel increases the generation of singlet oxygen (1O2) and hydroxyl radical (-OH), making the hydrogel system excellent antioxidant and antibacterial capabilities, these results demonstrate that the LTF-GO/Gel hydrogel has clinical promise as a wound dressing for wound healing. In vivo experiments unequivocally establish the capacity of the LTF-GO/Gel hydrogel to expedite wound healing and mitigate inflammation. This hydrogel, therefore, harbors immense potential for applications in wound healing.
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Antioxidantes , Hidrogéis , Humanos , Hidrogéis/farmacologia , Hidrogéis/química , Antioxidantes/farmacologia , Antioxidantes/química , Lactoferrina , Antibacterianos/farmacologia , Antibacterianos/química , Cicatrização , InflamaçãoRESUMO
The greater wax moth (GWM), Galleria mellonella (Lepidoptera: Pyralidae), is a major bee pest that causes significant damage to beehives and results in economic losses. Bacillus thuringiensis (Bt) appears as a potential sustainable solution to control this pest. Here, we develop a novel Bt strain (designated BiotGm) that exhibits insecticidal activity against GWM larvae with a LC50 value lower than 2 µg/g, and low toxicity levels to honey bee with a LC50 = 20598.78 µg/mL for larvae and no observed adverse effect concentration = 100 µg/mL for adults. We design an entrapment method consisting of a lure for GWM larvae, BiotGm, and a trapping device that prevents bees from contacting the lure. We find that this method reduces the population of GWM larvae in both laboratory and field trials. Overall, these results provide a promising direction for the application of Bt-based biological control of GWM in beehives, although further optimization remain necessary.
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Bacillus thuringiensis , Inseticidas , Mariposas , Abelhas , Animais , Controle Biológico de Vetores/métodos , Larva , Inseticidas/farmacologiaRESUMO
For several decades, urinary tract infections caused by catheter-associated devices have negatively impacted not only medical device utilization, but also patient health. As such, the creation of catheter materials with both superior biocompatibility and antibacterial properties has become necessary. This study aimed to produce electrospun membranes based on polylactic acid (PLA) with the incorporation of black phosphorus nanosheets (BPNS) and nano-zinc oxide (nZnO) particles, as well as a mixture of both, in order to design bifunctional membranes with enhanced bioactivity and antibacterial features. The optimum spinning process was determined through examination of various PLA mass concentrations, spinning solution propelling speeds, and receiving drum rotating speeds, with emphasis on the mechanical properties of PLA membranes. Additionally, the antibacterial properties and cytocompatibility of the ZnO-BP/PLA antibacterial membranes were explored. Results demonstrated that the ZnO-BP/PLA antibacterial membranes displayed a rich porous structure, with uniform distribution of nZnO particles and BPNS. With the increase of polylactic acid concentration and the decrease of spinning solution advancing and drum rotation speeds, the mechanical properties of the fiber membrane were significantly improved. Furthermore, the composite membranes exhibited remarkable photothermal therapy (PTT) capabilities when aided by the synergistic effect of BP nanosheets and ZnO. This was achieved through near-infrared (NIR) irradiation, which not only dissipated the biofilm but also enhanced the release capability of Zn2+. Consequently, the composite membrane demonstrated an improved inhibitory effect on both Escherichia coli and Staphylococcus aureus. The results of cytotoxicity and adhesion experiments also indicated good cytocompatibility, with cells growing normally on the surface of the ZnO-BP/PLA antibacterial membrane. Overall, these findings validate the utilization of both BPNS and n-ZnO fillers in the creation of novel bifunctional PLA-based membranes, which possess both biocompatibility and antibacterial properties for interventional catheter materials.
Assuntos
Óxido de Zinco , Humanos , Óxido de Zinco/farmacologia , Óxido de Zinco/química , Antibacterianos/farmacologia , Antibacterianos/química , Poliésteres/química , Catéteres , Ácido LácticoRESUMO
Ferroptosis is a novel form of regulated cell death induced by iron-dependent lipid peroxidation imbalance. It has emerged as a promising antitumor therapeutic strategy in recent years. In this work, we successfully synthesized a complex magnetic nanocube Fe3O4 modified with PEI and HA by the thermal decomposition method. While loading a ferroptosis inducer RSL3 inhibited cancer cells through the ferroptosis signal transduction pathway. The drug delivery system could actively target tumor cells through an external magnetic field and HA-CD44 binding. Zeta potential analysis showed that Fe3O4-PEI@HA-RSL3 nanoparticles were more stable and uniformly dispersed in tumor acidic environment. Moreover, cellular experiments demonstrated that Fe3O4-PEI@HA-RSL3 nanoparticles could significantly inhibit the proliferation of hepatoma cells without a cytotoxic effect on normal hepatic cells. In addition, Fe3O4-PEI@HA-RSL3 played a vital role in ferroptosis by accelerating ROS production. The expression of ferroptosis-related genes Lactoferrin, FACL 4, GPX 4 and Ferritin was significantly suppressed with increasing treatment of Fe3O4-PEI@HA-RSL3 nanocubes. Therefore, this ferroptosis nanomaterial has great potential in Hepatocellular carcinoma (HCC) therapy.
Assuntos
Carcinoma Hepatocelular , Ferroptose , Neoplasias Hepáticas , Nanopartículas , Humanos , Carcinoma Hepatocelular/tratamento farmacológico , Espécies Reativas de Oxigênio/metabolismo , Morte Celular , Neoplasias Hepáticas/tratamento farmacológico , Nanopartículas/químicaRESUMO
Large-scale soil salinity surveys are time-costly and labor-intensive, and it is also more difficult to investigate historical salinity, while in arid and semi-arid regions, the investigation of the spatial and temporal characteristics of salinity can provide a scientific basis for the scientific prevention of salinity, With this objective, this study uses multi-source data combined with ensemble learning and Google Earth Engine to build a monitoring model to observe the evolution of salinization in the Werigan-Kuqa River Oasis from 1996 to 2021 and to analyze the driving factors. In this experiment, three ensemble learning models, Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Light Gradient Boosting Machine (LightGBM), were established using data collected in the field for different years and some environmental variables, After the accuracy validation of the model, XGBoost had the highest accuracy of salinity prediction in this study area, with RMSE of 17.62 dS m-1, R2 of 0.73 and RPIQ of 2.45 in the test set. In this experiment, after Spearman correlation analysis of soil Electrical Conductivity (EC) with environmental variables, we found that the near-infrared band in the original band, the DEM in the topographic factor, the vegetation index based on remote sensing, and the salinity index soil EC had a strong correlation. The spatial distribution of salinization is generally characterized by good in the west and north and severe in the east and south. Non-salinization, light salinization, and moderate salinization gradually expanded southward and eastward from the interior of the western oasis over 25 years. Severe and very severe salinization gradually shifted from the northern edge of the oasis to the eastern and southeastern desert areas during the 25 years. The saline soils with the highest salinity class were distributed in most of the desert areas in the eastern part of the Werigan-Kuqa Oasis study area as well as in smaller areas in the west in 1996, shrinking in size and characterized by a discontinuous distribution by 2021. In terms of area change, the non-salinized area increased from 198.25 in 1996 to 1682.47 km2 in 2021. The area of saline soil with the highest salinization level decreased from 5708.77 in 1996 to 2246.87 km2 in 2021. overall, the overall salinization of the Werigan-Kuqa Oasis improved.
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For decades, calcium phosphate bone cements (CPCs) showed impressive advantages for their good biocompatibility, injectability, and osteoconductivity in the bone repair field. However, it is still difficult to prepare CPCs with outstanding antibacterial and self-curing properties, sufficient phosphorus release, and osteoinductivity for clinical application. Herein, we used partially crystallized calcium phosphate and dicalcium phosphate anhydrate particles incorporated with black phosphorous nanosheets to prepare calcium phosphate bone cements (CPCs). The curing time, compressive strength, photothermal properties, and degradation performance of BP/CPC were investigated. In addition, the cytocompatibility and osteoinductivity of BP/CPC were evaluated by cell adhesion, cytotoxicity, alkaline phosphatase detection, alizarin red staining, and western blot assay. The results indicated that BP/CPC showed adjustable curing time, good cytocompatibility, outstanding photothermal properties, and osteoinductivity, suggesting their potential application for bone regeneration.
Assuntos
Cimentos Ósseos , Osteogênese , Cimentos Ósseos/farmacologia , Fosfatos de Cálcio/farmacologia , Regeneração ÓsseaRESUMO
Hepatocellular carcinoma (HCC) is one of the deadliest tumors in the world with a high rate of recurrence and metastasis. Therefore, the most pressing issue today is the development of new drugs, diagnostic and therapeutic approaches for effective cancer treatment. Cancer stem cells (CSCs) play a pivotal role in tumor recurrence, tumor resistance, and tumor metastasis, which provides a new perspective on the development of liver cancer. In the study, a high-temperature thermal breakdown approach was used to create composite magnetic nanocubes modified by polyethyleneimine (PEI) and hyaluronic acid (HA). The Fe3O4 nanocubes can recognize HCC stem cells via receptor-ligand binding of HA and CD44 (HA receptor). While loading a small molecule LDN193189 inhibited the expression of stemness-related genes OCT4 and Nanog. More crucially, the Fe3O4 nanocubes significantly suppressed HCC cell proliferation and migration by regulating the expression of epithelial-mesenchymal transition (EMT) process markers E-cadherin, Vimentin, and N-cadherin. Dual targeting using magnetic and receptor-mediated targeting improved the uptake of the drug delivery system. Our findings imply that the medication delivery method might be a potential therapeutic strategy for HCC.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Transição Epitelial-Mesenquimal , Ácido Hialurônico/farmacologia , Linhagem Celular Tumoral , Células-Tronco Neoplásicas/patologia , Caderinas/metabolismo , Movimento Celular , Regulação Neoplásica da Expressão GênicaRESUMO
Despite many studies have revealed that developing honey bee (Apis mellifera) larvae are posting a high risk on exposure to insecticides, the toxicology information on bee larvae remain limited. The present study demonstrated the first assessment of the effects of no observed adverse effect concentration (NOAEC) of carbaryl (CR) and acetamiprid (ACE) on transcriptome and metabolome in honeybee larvae reared in vitro. Chronic exposure to carbaryl caused transcriptional disorders associated with oxidative stress. In addition, a series of metabolic homeostasis were disrupted by carbaryl stress, such amino acid metabolism, purine and pyrimidine metabolism and flavone and flavonol biosynthesis. The activities of enzymic biomarkers including GST, P450, CAT, AChE and SOD were not influenced by ACE stress, while the CR exposure slightly decreased the activity of CAT and SOD. Our results clearly show that ACE and CR display different potential to modulate transcriptome and metabolome associated with their different toxicity against bee larvae.
Assuntos
Flavonas , Inseticidas , Aminoácidos/farmacologia , Animais , Abelhas/genética , Biomarcadores/metabolismo , Carbaril/toxicidade , Flavonas/farmacologia , Flavonóis/farmacologia , Inseticidas/toxicidade , Larva , Neonicotinoides , Purinas/farmacologia , Pirimidinas/farmacologia , Superóxido Dismutase/metabolismo , TranscriptomaRESUMO
Tropilaelaps mercedesae is one of the most problematic honey bee parasites and has become more threatening to the beekeeping industry. Tropilaelaps can easily parasitize immature honey bees (larvae and pupae) and have both lethal and sublethal effects on the individual worker bees. Our study for the first time experimentally assessed the effects of T. mercedesae on olfactory learning, flight ability, homing ability as well as transcriptional changes in parasitized adult honey bees. T. mercedesae infestation had negative impacts on olfactory associated function, flight ability, and homing rate. The volume of the mushroom body significantly increased in infested honey bees, which may be correlated to the lower sucrose responsiveness as well as lower learning ability in the infested bees. The gene expression involved in immune systems and carbohydrate transport and metabolism were significantly different between infested bees and non-infested bees. Moreover, genes function in cell adhesion play an essential role in olfactory sensory in honey bees. Our findings provide a comprehensive understanding of European honey bees in response to T. mercedesae infestation, and could be used to further investigate the complex molecular mechanisms in honey bees under parasitic stress.
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Abelhas/parasitologia , Comportamento Animal , Expressão Gênica , Varroidae , AnimaisRESUMO
Tropilaelaps mercedesae is not only a major threat to honey bees in Asia but also a potential risk to global apiculture due to trade. Imidacloprid is a systemic insecticide that negatively affects individual bees. Moreover, the health of honey bees may be threatened by imidacloprid exposure and T. mercedesae infestation. We studied the effects of T. mercedesae and imidacloprid on the survival, food consumption and midgut bacterial diversity of Apis mellifera in the laboratory. Illumina 16S rRNA gene sequencing was used to determine the bacterial composition in the honey bee midgut. T. mercedesae decreased survival in parasitized honey bees compared with nonparasitized honey bees, but there was no significant difference in food consumption. The imidacloprid 50 µg/L diet significantly decreased syrup consumption of A. mellifera compared with the control diet. The combination of T. mercedesae infestation and imidacloprid 50 µg/L exposure reduced survival and increased pollen consumption of A. mellifera. T. mercedesae infestation or a combination of T. mercedesae infestation and exposure to 25 µg/L imidacloprid affected the midgut bacterial composition of honey bees. T. mercedesae infestation and imidacloprid exposure may reduce the survival and affect honey bee health.
Assuntos
Inseticidas , Nitrocompostos , Animais , Ásia , Abelhas , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Pólen , RNA Ribossômico 16S/genéticaRESUMO
With the development of online advertising technology, the accurate targeted advertising based on user preferences is obviously more suitable both for the market and users. The amount of conversion can be properly increased by predicting the user's purchasing intention based on the advertising Conversion Rate (CVR). According to the high-dimensional and sparse characteristics of the historical behavior sequences, this paper proposes a LSLM_LSTM model, which is for the advertising CVR prediction based on large-scale sparse data. This model aims at minimizing the loss, utilizing the Adaptive Moment Estimation (Adam) optimization algorithm to mine the nonlinear patterns hidden in the data automatically. Through the experimental comparison with a variety of typical CVR prediction models, it is found that the proposed LSLM_LSTM model can utilize the time series characteristics of user behavior sequences more effectively, as well as mine the potential relationship hidden in the features, which brings higher accuracy and trains faster compared to those with consideration of only low or high order features.
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BACKGROUND: The effects of exposing Apis mellifera larvae to common insecticides were tested in the laboratory. RESULTS: The acute toxicity values of the four insecticides that we tested ranged from high toxicity to low toxicity: deltamethrin > cypermethrin > carbaryl > acetamiprid. The NOAEC (no observed adverse effect concentration) values of the chronic toxicity tests for each compound are 5 mg L-1 for acetamiprid, 2 mg L-1 for carbaryl, 1 mg L-1 for cypermethrin, and 0.2 mg L-1 for deltamethrin. CONCLUSION: According to the risk quotient (RQ) values of acute and chronic toxicity that we obtained, the risk is acceptable at exposure rates that have been identified in the field. Overall, our results are valuable for evaluating the acute and chronic toxicities of these insecticides to developing honey bees. © 2019 Society of Chemical Industry.
Assuntos
Abelhas , Animais , Carbaril , Inseticidas , Larva , Neonicotinoides , Nitrilas , PiretrinasRESUMO
Tropilaelaps mercedesae is an ectoparasite of Apis mellifera in Asia and is considered a major threat to honey bee health. Herein, we used the Illumina MiSeq platform 16S rDNA Amplicon Sequencing targeting the V3-V4 regions and analysed the effects on the midgut bacterial communities of honey bees infested with T. mercedesae. The overall bacterial community in honey bees infested with T. mercedesae were observed at different developmental stages. Honey bee core intestinal bacterial genera such as Gilliamella, Lactobacillus and Frischella were detected. Tropilaelapsmercedesae infestation changed the bacterial communities in the midgut of A. mellifera. Tropilaelapsmercedesae-infested pupae had greatly increased relative abundances of Micrococcus and Sphingomonas, whereas T. mercedesae-infested 15-day-old workers had significantly reduced relative abundance of non-core microbes: Corynebacterium, Sphingomonas, Acinetobacter and Enhydrobacter compared to T. mercedesae-infested newly emerged bees. The bacterial community was significantly changed at the various T. mercedesae-infested developmental stages of A. mellifera. Tropilaelapsmercedesae infestation also changed the non-core bacterial community from larvae to newly emerged honey bees. Bacterial communities were significantly different between T. mercedesa-infested and non-mite-infested 15-day-old workers. Lactobacillus was dominant in T. mercedesae-infested 15-day-old workers compared to non-mite-infested 15-day-old workers.
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Bactérias/isolamento & purificação , Abelhas/microbiologia , Microbioma Gastrointestinal , Animais , Bactérias/classificação , Bactérias/genética , Fenômenos Fisiológicos Bacterianos , China , Ácaros/fisiologia , RNA Bacteriano/análise , RNA Ribossômico 16S/análiseRESUMO
The effects of Bt Cry9Ee toxin on honey bee, Apis mellifera L., survival, developmental rate, larval weight, pollen consumption, and midgut bacterial diversity were tested in the laboratory. Honey bee larvae and adults were reared in vitro and fed a diet that contained Cry9Ee toxin at 0.01, 0.1, 1, and 10â¯mg/L. Cry9Ee toxin 0.01, 0.1, and 1â¯mg/L in diet used in this study may represent a value closer to field relevance and the highest concentration is unlikely to be encountered in the field and thus represent a worst case scenario. The dependent variables were compared for groups of honey bees feeding on treated diet and those feeding on negative control (no addition of a test substance), solvent control (0.01â¯mM Na2CO3), and positive control diet (dimethoate 45â¯mg/L). Bt Cry9Ee toxin did not affect survival or larval weight, and the result was great confidence in accepting the null hypothesis by power analysis. The effect on development rates and pollen consumption were the inconclusive results because the post-hoc power was less than 0.8. Furthermore, the midgut bacterial structure and compositions were determined using high-throughput sequencing targeting the V3-V4 regions of the 16S rDNA. All core honey bee intestinal bacterial class such as γ-Proteobacteria, Actinobacteria, α-Proteobacteria, Bacilli, ß-Proteobacteria, and Bacteroidia were detected, and no significant changes were found in the species diversity and richness between Cry9Ee treatments and laboratory control.
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Proteínas de Bactérias/toxicidade , Abelhas/efeitos dos fármacos , Endotoxinas/toxicidade , Proteínas Hemolisinas/toxicidade , Animais , Toxinas de Bacillus thuringiensis , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Abelhas/crescimento & desenvolvimento , Sistema Digestório/microbiologia , Larva/efeitos dos fármacos , PólenRESUMO
The acute and chronic toxicity of 3 common pesticides, namely, amitraz, chlorpyrifos and dimethoate, were tested in Apis mellifera and Apis cerana. Acute oral toxicity LC50 values were calculated after 24â¯h of exposure to contaminated syrup, and chronic toxicity was tested after 15 days of exposure to 2 sublethal concentrations of pesticides. The toxicity of the tested pesticides to A. mellifera and A. cerana decreased in the order of dimethoateâ¯>â¯chlorpyrifosâ¯>â¯amitraz. A. mellifera was slightly more sensitive to chlorpyrifos and dimethoate than A. cerana, while A. cerana was more sensitive to amitraz than A. mellifera. Chronic toxicity tests showed that 1.0â¯mg/L dimethoate reduced the survival of the two bee species and the food consumption of A. mellifera, while 1.0â¯mg/L amitraz and 1.0â¯mg/L chlorpyrifos did not affect the survival or food consumption of the two bee species. The treatment of syrup with amitraz at a concentration equal to 1/10th of the LC50 value did not affect the survival of or diet consumption by A. mellifera and A. cerana; however, chlorpyrifos and dimethoate at concentrations equal to 1/10th of their respective LC50 values affected the survival of A. cerana. Furthermore, intestinal bacterial communities were identified using high-throughput sequencing targeting the V3V4 regions of the 16S rDNA gene. All major honey bee intestinal bacterial phyla, including Proteobacteria (62.84%), Firmicutes (34.04%), and Bacteroidetes (2.02%), were detected. There was a significant difference in the microbiota species richness of the two species after 15 days; however, after 30 days, no significant differences were found in the species diversity and richness between A. cerana and A. mellifera exposed to 1.0â¯mg/L amitraz and 1.0â¯mg/L chlorpyrifos. Overall, our results confirm that acute toxicity values are valuable for evaluating the chronic toxicity of these pesticides to honey bees.