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Water buffalo horn (WBH), a traditional Chinese medicine, is known for its antipyretic, anti-inflammatory and antioxidant properties. This study aims to investigate the therapeutic potential of WBH keratin (WBHK) and its derived thiol-rich peptide fractions (SHPF) for oxidative stress and inflammation. WBHK and SHPF were prepared and tested using various models including LPS-induced fever in rabbits, H2O2-induced oxidative damage in bEnd.3 cells, TNF-α-induced inflammation in bEnd.3 cells and LPS-induced inflammation in RAW 264.7 cells. Expression of key markers, such as Nrf2, Hmox-1 and NF-κB, were analyzed using qRT-PCR, ELISA and Western blotting. Label-free quantitative proteomic analysis was used to identify key differential proteins associated with the efficacy of SHPF. Our results demonstrated that treatment with WBHK significantly reduced body temperature after 0.5 h of administration in the fever rabbit model. SHPF could alleviate cellular inflammatory injury and oxidative damage by activating the key transcription factor Nrf2 and increasing the expression level of Hmox-1. SHPF could inhibit the NF-κB pathway by reducing IκB phosphorylation. It was also found that SHPF could reduce pro-inflammatory cytokine (IL-6, COX-2 and PGE2) and inhibit the expression of VCAM-1, ICAM-1, IL-6 and MCP-1. Proteomics analysis showed that SHPF could inhibit HMGB1 expression and release. The results indicated that SHPF could significantly reduce inflammation and oxidative stress by regulating the Nrf2/Hmox-1 and NF-κB pathways. These findings suggest the potential therapeutic applications of WBH components in the treatment of oxidative stress and inflammation-related diseases.
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BACKGROUND: Saiga antelope horn (SAH) is a traditional Chinese medicine for treating febrile seizure (FS) with precise efficacy, but its mechanism of action and functional substances are still unclear. Given the need for further research on SAH, our group conducted studies to elucidate its mechanisms and active substances. METHODS: An FS rat pup model was constructed through intraperitoneal injection of LPS and hyperthermia induction. Behavioural indicators of seizures, hippocampal histopathological alterations, serum levels of inflammatory cytokines and hippocampal levels of neurotransmitters were observed and measured to investigate the effects of SAH on FS model rats. Hippocampal metabolomics and network pharmacology analyses were conducted to reveal the differential metabolites, key peptides and pathways involved in the suppression of FS by SAH. RESULTS: SAH suppressed FS, decreased the inflammatory response and regulated the Glu-GABA balance. Metabolomic analysis revealed 13 biomarkers of FS, of which SAH improved the levels of 8 differential metabolites. Combined with network pharmacology, a "biomarker-core target-key peptide" network was constructed. The peptides of SAH, such as YGQL and LTGGF, could exert therapeutic effects via the arachidonic acid pathway. Molecular docking and ELISA results indicated that functional peptides of SAH could bind to PTGS2 target, inhibiting the generation of AA and its metabolites in hippocampal samples. CONCLUSION: In summary, the functional peptides contained in SAH are the main material basis for the treatment of FS, potentially acting through neurotransmitter regulation and the arachidonic acid pathway.
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Due to the highly stable structure of keratin, the extraction and dissolution steps of animal medicines rich in keratin are complex, which seriously restricts the detection efficiency and flux. Therefore, this study simplified the pre-treatment steps of horn samples and optimized the detection methods of characteristic peptides to improve the efficiency of identifying the specificity of horn-derived animal medicines. For detection of the characteristic peptides in horn-derived animal medicines treated with/without iodoace-tamide(IAA), the ion pair conditions of the characteristic peptides were optimized, and the retention time, intensity and other data of the specific peptides were compared between the samples treated with/without IAA. Two pre-treatment methods, direct enzymatic hydrolysis and total protein extraction followed by enzymatic hydrolysis, were used to prepare horn-derived animal medicine samples. The effects of different methods on the detection of specific peptides in the samples of Saiga antelope horn, water buffalo horn, goat horn, and yak horn were compared regarding the retention time of specific peptides and ion intensity. The results indicated that after direct enzymatic hydrolysis, the specific peptides in the samples without IAA treatment can be detected. Compared with the characteristic peptides in the samples treated with IAA, their retention time shifted back and the mass spectrometry response slightly decreased. The specific peptides of the samples without IAA treatment had good specificity and did not affect the specificity identification of horn-derived animal medicines. Overall, the process of direct enzymatic hydrolysis can be used to treat horn samples, omitting the steps of protein extraction and dithiothreitol and IAA treatment, significantly improving the pre-treatment efficiency without affecting the specificity identification of horn-derived animal medicines. This study provides ideas for quality research and standard improvement of horn-derived animal medicines.
Subject(s)
Horns , Keratins , Peptides , Animals , Horns/chemistry , Peptides/chemistry , Keratins/chemistry , Cattle , Goats , Buffaloes , Chromatography, High Pressure LiquidABSTRACT
ETHNOPHARMACOLOGICAL RELEVANCE: Saiga antelope horn (SAH) is a traditional Chinese medicine for treating hypertension with liver-yang hyperactivity syndrome (Gan-Yang-Shang-Kang, GYSK), that has a long history of clinical application and precise efficacy, but its mechanism and functional substances are still unknown. Based on the demand for alternative research on the rare and endangered SAH, the group designed and carried out the following studies. AIM OF THE STUDY: The purpose of this research was to demonstrate the functional substances and mechanisms of SAH in the treatment of GYSK hypertension. MATERIALS AND METHODS: The GYSK-SHR model was constructed by administering a decoction of aconite to spontaneously hypertensive rats (SHRs). Blood pressure (BP), behavioural tests related to GYSK, and pathological changes in the kidneys, heart and aorta were measured to investigate the effects of SAH on GYSK-SHRs. Proteomic analysis was used to identify the keratins and peptides of SAH. Moreover, network pharmacology and plasma metabolomics studies were carried out to reveal the mechanisms by which functional peptides in SAH regulate GYSK-hypertension. RESULTS: SAH has a significant antihypertensive effect on GYSK hypertensive animals. It has also been proven to be effective in protecting the function and structural integrity of the kidneys, heart and aorta. Moreover, SAH improved the abnormalities of 31 plasma biomarkers in rats. By constructing a "biomarker-target-peptide" network, 10 functional peptides and two key targets were screened for antihypertensive effects of SAH. The results indicated that SAH may exert a therapeutic effect by re-establishing the imbalance of renin-angiotensin (RAS) system. CONCLUSIONS: Functional peptides from keratin contained in SAH are the main material basis for the treatment of GYSK-hypertension and exhibited the protective effect on the GYSK-SHR model through the RAS system.
Subject(s)
Antihypertensive Agents , Hypertension , Medicine, Chinese Traditional , Metabolomics , Network Pharmacology , Rats, Inbred SHR , Animals , Hypertension/drug therapy , Hypertension/physiopathology , Male , Antihypertensive Agents/pharmacology , Antihypertensive Agents/therapeutic use , Rats , Medicine, Chinese Traditional/methods , Blood Pressure/drug effects , Antelopes , Liver/drug effects , Liver/metabolism , Liver/pathology , Horns , Drugs, Chinese Herbal/pharmacology , Drugs, Chinese Herbal/therapeutic use , Disease Models, AnimalABSTRACT
This paper proposed a single-layer checkerboard metasurface with simultaneous wideband radar cross-section (RCS) reduction characteristics and low infrared (IR) emissivity. The metasurface consists of an indium tin oxide (ITO)-patterned film, a polyethylene terephthalate (PET) substrate and an ITO backplane from the top downwards, with a total ultra-thin thickness of 1.6 mm. This design also allows the metasurface to have good optical transparency and flexibility. Based on phase cancellation and absorption, the metasurface can achieve a wideband RCS reduction of 10 dB from 10.6 to 19.4 GHz under normal incidence. When the metasurface is slightly cylindrically curved, an RCS reduction of approximately 10 dB can still be achieved from 11 to 19 GHz. The polarization and angular stability of the metasurface have also been verified. The filling rate of the top ITO-patterned film is 0.81, which makes the metasurface have a low theoretical IR emissivity of 0.24. Both simulation and experimental results have verified the excellent characteristics of the proposed checkerboard metasurface, demonstrating its great potential application in radar-IR bi-stealth.
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With the development of the Internet of Things (IoT), the use of UAV-based data collection systems has become a very popular research topic. This paper focuses on the energy consumption problem of this system. Genetic algorithms and swarm algorithms are effective approaches for solving this problem. However, optimizing UAV energy consumption remains a challenging task due to the inherent characteristics of these algorithms, which make it difficult to achieve the optimum solution. In this paper, a novel particle swarm optimization (PSO) algorithm called Double Self-Limiting PSO (DSLPSO) is proposed to minimize the energy consumption of the unmanned aerial vehicle (UAV). DSLPSO refers to the operational principle of PSO and incorporates two new mechanisms. The first mechanism is to restrict the particle movement, improving the local search capability of the algorithm. The second mechanism dynamically adjusts the search range, which improves the algorithm's global search capability. DSLPSO employs a variable population strategy that treats the entire population as a single mission plan for the UAV and dynamically adjusts the number of stopping points. In addition, the proposed algorithm was also simulated using public and random datasets. The effectiveness of the proposed DSLPSO and the two new mechanisms has been verified through experiments. The DSLPSO algorithm can effectively improve the lifetime of the UAV, and the two newly proposed mechanisms have potential for optimization work.
Subject(s)
Algorithms , Unmanned Aerial Devices , Movement , Physical Phenomena , InternetABSTRACT
ETHNOPHARMACOLOGICAL RELEVANCE: Bufei Huoxue capsule (BHC) as a classic Chinese patent medicine formula, has the efficacy of tonifying the lungs and activating the blood. It has been extensively used in China for the treatment of chronic obstructive pulmonary disease (COPD) clinically. However, its mechanism is still unclear, which hampers the applications of BHC in treating COPD. AIM OF THE STUDY: The purpose of the present study was to demonstrate the protective efficacy and mechanism of BHC on COPD model rats by integrating serum metabolomics analysis and network pharmacology study. MATERIALS AND METHODS: A COPD rat model was established by cigarette fumigation combined with lipopolysaccharide (LPS) airway drip for 90 consecutive days. After oral administration for 30 days, the rats were placed in the body tracing box of the EMKA Small Animal Noninvasive Lung Function Test System to determine lung function related indexes. Histopathological alteration was observed by H&E staining and Masson staining. The serum levels of inflammatory cytokine, matrix metalloprotein 9, and laminin were determined by ELISA kits. Oxidative stress levels were tested by biochemical methods. UHPLC-Q-TOF/MS analysis of serum metabolomics and network pharmacology were performed to reveal the bioactive metabolites, key components and pathways for BHC treating COPD. WB and ELISA kits were used to verify the effects of BHC on key pathway. RESULTS: BHC could improve lung function, immunity, lung histopathological changes and collagen deposition in COPD model rats. It also could significantly reduce inflammatory response in vivo, regulate oxidative stress level, reduce laminin content, and regulate protease-antiprotease balance. Metabolomics analysis found 46 biomarkers of COPD, of which BHC significantly improved the levels of 23 differential metabolites including arachidonic acid, leukotriene B4 and prostaglandin E2. Combined with the results of network pharmacology, the components of BHC, such as calycosin, oxypaeoniflora, (S)-bavachin and neobavaisoflavone could play therapeutic roles through the arachidonic acid pathway. In addition, the results of WB and ELISA indicated that BHC could suppress the expressions of COX2 and 5-LOX in lung tissues and inhibit the generation of AA and its metabolites in serum samples. Regulation of arachidonic acid metabolic pathway may be the crucial mechanism for BHC treating COPD. CONCLUSIONS: In summary, the studies indicated that BHC exhibited the protective effect on COPD model rats by anti-inflammatory and anti-oxidative properties through arachidonic acid metabolism pathway. This study provided beneficial support for the applications of BHC in treating COPD.
Subject(s)
Drugs, Chinese Herbal , Medicine, Chinese Traditional , Pulmonary Disease, Chronic Obstructive , Rats , Animals , Network Pharmacology , Arachidonic Acid , Rats, Sprague-Dawley , Pulmonary Disease, Chronic Obstructive/metabolism , Metabolomics/methods , Drugs, Chinese Herbal/pharmacology , Drugs, Chinese Herbal/therapeutic use , LamininABSTRACT
A transparent metamaterial absorber (MMA) with both tunable absorption bandwidth and low infrared (IR) emissivity is proposed in this paper. The MMA is hierarchical, which consists of an infrared shielding layer (IRSL), two radar-absorption layers (RALs), an air/water layer, and an indium-tin-oxide (ITO) backplane from the top downwards. The IRSL and the RALs are made of ITO patterns etched on polyethylene terephthalate (PET) substrates. By changing the thickness of the water, the 90% absorption bandwidth can be tuned from 6.4-11.3 GHz to 12.7-20.6 GHz, while retaining good polarization and angular stability. An equivalent circuit model (ECM) is present, to reveal the physical mechanism of absorption. The proposed MMA has a low theoretical IR emissivity of about 0.24. A sample was fabricated and measured, and the experimental results are consistent with the simulation results, showing its potential applications in stealth glass and multifunctional radome.
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BACKGROUND: Pharmaceutical care has the potential to improve hypertension control rates in young and middle-aged patients. Due the COVID-19 epidemic, standard intervention methods may not be applicable. We propose establishing an internet-based pharmaceutical care (IPC) route to improve blood pressure control in young and middle-aged patients with hypertension. An evaluation method based on Principal Component Analysis (PCA) and Orthogonal Partial Least-Discriminant Analysis (OPLS-DA) was established to evaluate the effect of the IPC method. METHODS: 1) Internet-based Pharmaceutical care (IPC) was provided by pharmacists mainly using Wechat software for one year after enrollment; 2) PCA and OPLS-DA were applied to analyze questionnaire reliability and data variability; 3) Markov cohort was used to evaluate the IPC effect. RESULTS: Ninety-seven young and middle-aged patients were enrolled. 96 patients received the IPC. 1) The blood pressure control rate increased to 71.88% after IPC in 96 patients. 2) After conducting PCA and OPLS-DA analysis, 10 questions in the questionnaire were significantly improved after the IPC. 3) Markov cohort results showed that patient survival after 28 cycles was 18.62 years and the quality-adjusted life year (QALY) was extended by 5.40 years. The cumulative cost-effectiveness ratio was ¥87.10 per QALY. CONCLUSIONS: The IPC method could significantly improve the blood pressure control rate of patients. The questionnaire analysis method based on PCA and OPLS-DA is an effective method to evaluate the effect of the IPC method. The Markov cohort showed that the IPC had an effect on blood pressure control rate changes. Patients had a strong willingness to pay for IPC.
Subject(s)
COVID-19 , Hypertension , Middle Aged , Humans , Principal Component Analysis , COVID-19/epidemiology , Pandemics , Reproducibility of Results , Quality of Life , Hypertension/drug therapy , InternetABSTRACT
Alzheimer's disease (AD) seriously influences human health, and there is no effective treatment to prevent or cure AD. Recent studies have shown that angiotensin II type 1 receptor (AT1R) blockers significantly reduce the prevalence of AD, while the precise role and mechanism of AT1R in AD remain obscure. In this study, for the first time, we identified that astrocytic but not neuronal AT1R levels were significantly increased in AD model rats and found that astrocyte-specific knockout of AT1R significantly ameliorated amyloid ß (Aß)-induced cognitive deficits and synaptotoxicity. Pretreating astrocytes with an AT1R blocker also alleviated Aß-induced synaptotoxicity in the coculture system of hippocampal neurons and astrocytes. Moreover, AT1R could directly bind to Aß1-42 and activate the astrocytic ß-arrestin2 pathway in a biased manner, and biased inhibition of the astrocytic AT1R/ß-arrestin2 pathway relieved Aß-induced neurotoxicity. Furthermore, we demonstrated that astrocytic AT1R/ß-arrestin2 pathway-mediated synaptotoxicity was associated with the aggregation of autophagosomes, which triggered the disordered degradation of Aß. Our findings reveal a novel molecular mechanism of astrocytic AT1R in Aß-induced neurodegeneration and might contribute to establishing new targets for AD prevention and therapy.
Subject(s)
Alzheimer Disease , Amyloid beta-Peptides , Animals , Humans , Rats , Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Astrocytes/metabolism , beta-Arrestin 2/metabolism , beta-Arrestin 2/pharmacology , Cognition , Receptor, Angiotensin, Type 1/metabolismABSTRACT
BACKGROUND: Hemorrhage, in particular noncompressible hemorrhage, is the leading cause of casualties in combat trauma and civilian trauma. Although systemic agents can stop bleeding at both inaccessible and accessible injury sites, the application of systemic hemostats in clinics is strictly limited by the nontargeting ability of hemostats and their subsequent potential for thromboembolic complications. OBJECTIVES: To engineer an anticoagulant/procoagulant self-converting and bleeding site-targeting systemic nanohemostat to rapidly control noncompressible bleeding without thrombosis risk. METHODS: A multiscale computer simulation was taken to guide the self-assembly of sulindac (SUL, a prodrug of the antiplatelets agent) and poly-L-lysine (a cation polymer with platelets activation ability) for forming poly-L-lysine/SUL nanoparticles (PSNs). In vitro platelet-adhering ability, platelet activation effect, and hemostasis activity of PSNs were evaluated. Then, the biosafety, level of thrombosis, targeting ability, and hemostasis effect of systemic applied PSNs were carefully evaluated in various hemorrhage models. RESULTS: PSNs were successfully prepared and showed good platelet adhesion and activation in vitro. The bleeding site-targeting ability and hemostatic efficiency in different bleeding models were leveled up by PSNs markedly compared with vitamin K and etamsylate in vivo. SUL in PSNs could be metabolized into sulindac sulfide at clot sites in 4 hours for antiplatelet aggregation, thus reducing thrombotic risk compared with other hemostatic agents, via the ingenious utilization of prodrug metabolism in terms of time intervals and the adhesion on platelets. CONCLUSION: PSNs are expected to be a low-cost, safe, efficient, clinically translatable first-aid hemostat for first-aid scenarios.
Subject(s)
Hemostatics , Prodrugs , Thrombosis , Humans , Anticoagulants/therapeutic use , Computer Simulation , Polylysine/pharmacology , Polylysine/therapeutic use , Prodrugs/pharmacology , Prodrugs/therapeutic use , Hemorrhage/chemically induced , Hemorrhage/drug therapy , Hemostasis , Hemostatics/therapeutic use , Thrombosis/drug therapyABSTRACT
Saiga antelope horn and Rhinoceros horn have been used in traditional Chinese medicine for thousands of years. However, due to the protection of wildlife, the application of these rare animal horns has been restricted or prohibited. Therefore, water buffalo horn, goat horn, and yak horn have been applied as alternatives to Rhinoceros horn or Saiga antelope horn in a clinic. It is extremely difficult to distinguish normal animal horns in powdered or decocted form, especially identifying related species such as water buffalo horn, yak horn, and cattle horn. In this work, mathematics set and label-free proteomics analysis were combined for discovering keratin-derived specific peptide biomarkers. By using mathematics set analysis after nano liquid chromatography-tandem mass spectrometry-based proteomics, the selected species-specific peptides could be used to identify the authenticity of the Saiga antelope horn and goat horn. Furthermore, peptide biomarkers were selected to distinguish related species-derived horns, water buffalo horn, yak horn, and cattle horn. In total, eight peptide biomarkers were selected and applied for simultaneously distinguishing different horn samples. The present strategy provides a method for peptide biomarkers discovery and also has positive significance for ensuring the quality and efficacy of animal horn-derived traditional Chinese medicines and their products.
Subject(s)
Antelopes , Horns , Animals , Cattle , Medicine, Chinese Traditional , Keratins , Buffaloes , Proteomics , Horns/chemistry , Peptides/analysis , Perissodactyla , Goats , Biomarkers/analysis , MathematicsABSTRACT
The effects of laser parameters on the microstructure and properties of plasma-sprayed yttrium oxide coating on the graphite matrix were investigated. Tensile strength, porosity, roughness, and scratch meter tests were carried out to evaluate the critical load and mechanical properties of the coating after spraying and laser micro-melting. When the porosity and surface roughness of the coating are minimum, the critical load of the coating is 7.85 N higher than that of the spraying surface. After laser micromelting, the crystal phase of Y2O3 coating surface does not change, the crystallinity is improved, and fine grain strengthening occurs. When the laser power density is 75 W/mm2, the scanning speed is 30 mm/s, and the defocusing distance is 40 mm, the film base bonding performance and wear resistance of the material reach the maximum value. The failure of Y2O3 coating is mainly due to the degradation of mechanical properties such as film base bonding strength, surface porosity, and surface roughness, which leads to the local collapse of the material. The coating after laser micro-melting only presents particle disintegration at the end of the scratch area.
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The rhizome of Polygonatum cyrtonema (Polygonati Rhizoma) is widely consumed as medicine-homology-food in Asia for its tonic effect, which can be enhanced by traditional steam-sun drying for nine cycles. However, the multi-constituents variation in this process was unclear, and the necessity of nine cycles should be further discussed. In this study, the multiple constituents, including saccharides, amino acids, nucleosides and bases, lipids, saponins, homoisoflavones and cinnamamides, in P. cyrtonema treated with sun drying, heated air drying, each cycle of steam-heated air drying, infrared drying and microwave drying were compared. The results showed that the content of total saccharides increased in samples from one to four cycles of steam-heated air drying (365.0-945.6 mg/g) and decreased from four to nine (945.6-288.0 mg/g). The content of fructose increased in samples from one to six cycles (29.9-234.7 mg/g) and decreased from six to nine (234.7-177.7 mg/g). The abundance of most phospholipids and free fatty acids increased continuously from one to nine cycles while most of the amino acids, nucleosides and bases showed continuous declining trend. Principal component analysis showed that the samples treated with one to four cycles were wider in distance than four to nine, indicating the chemical composition tending to be stable after fourth steaming. If taking total saccharides, fructose, and phospholipids as the major quality indicator, four cycles of steam-heated air drying processing should be the ideal postharvest processing method to obtain better taste, flavor and functionality. Samples treated with heated-air drying and infrared drying were far in distance from steaming ones by hierarchical cluster analysis, which means these processing methods were not suitable to replace the traditional steam-sun drying process. Collectively, the above results will not only provide novel processing methods that will obtain the high active ingredients for P. cyrtonema, but also shed light on the optimization of processing technology for the industrial production of medicinal crops which need nine cycles of steam-sun drying processing.
Subject(s)
Polygonatum , Saponins , Carbohydrates , Rhizome , SteamABSTRACT
Chalcones, a class of natural lipase inhibitors, have received substantial attention from researchers in recent years. Although many kinds of chalcones are typically distributed in G. inflata, there is little literature about the anti-lipase activity of G. inflata extracts (GIEs). In the present study, a ligand fishing strategy for fast screening of lipase inhibitors from GIEs was thus proposed. Porcine pancreatic lipase (PPL) was firstly immobilized on carboxyl modified Fe3O4 magnetic nanoparticles (MNPs) to obtain PPL functionalized MNPs (PPL@MNPs), and then the PPL@MNPs were incubated with a bioactive fraction to fish out the ligands. Eight ligands were obtained and identified as one flavone together with seven chalcones. Licochalcone A, licochalcone D and licochalcone E inhibited pancreatic lipase (PL) with IC50 of 4.9, 3.2 and 5.8 µM, respectively. Meanwhile, investigation of the structure-activity relationship also revealed that isopentenyl and hydroxyl substituents at ring A were essential for the noncovalent inhibitory potency of the chalcones.
Subject(s)
Enzymes, Immobilized/chemistry , Glycyrrhiza/chemistry , Lipase/antagonists & inhibitors , Magnetite Nanoparticles/chemistry , Plant Extracts/pharmacology , Animals , Chalcones , Ligands , Molecular Docking Simulation , SwineABSTRACT
OBJECTIVES: The capsid protein (VP1) of the foot-and-mouth (FMD) AKT-III strain was expressed on the surface of the T7 phage capsid (AKT-T7 strain) and the potential of AKT-T7 strain as an FMD vaccine was evaluated. RESULTS: The AKT-T7 strain was successfully constructed and was not cytotoxic to BHK-21, MDBK, or sheep kidney cells. The AKT-T7 strain was well phagocytosed by mouse macrophages. Immunization of BALB/c mice revealed that animals were quickly induced and produced high levels of FMDV antibodies. Monitoring data indicated that FMDV antibody levels could be maintained at higher levels for longer periods of time. The AKT-T7 strain induced high levels of IFN-γ levels in mice with little effect on IL-4. CONCLUSIONS: The AKT-T7 induced the mice to produce FMDV antibodies, which has the advantage of phage and FMDV, and is a potential candidate for an FMD vaccine.
Subject(s)
Bacteriophage T7/genetics , Capsid Proteins , Foot-and-Mouth Disease Virus/genetics , Viral Vaccines , Animals , Antibodies, Viral/blood , Capsid Proteins/genetics , Capsid Proteins/immunology , Cell Line , Cells, Cultured , Cloning, Molecular , Cricetinae , Female , Macrophages/immunology , Mice , Mice, Inbred BALB C , Sheep , Viral Vaccines/chemistry , Viral Vaccines/genetics , Viral Vaccines/immunologyABSTRACT
Iron is a fundamental element required by most organisms, including Brucella. Several researchers have suggested that the iron response regulator (irr) and rhizobial iron regulator (rirA) genes regulate iron acquisition by Brucella abortus, influencing heme synthesis by and virulence of this pathogen. However, little is known about another Brucella species, Brucella melitensis. In this research, we successfully constructed two mutants: M5-90Δirr and M5-90ΔrirA. The adhesion, invasion, and intracellular survivability of these two mutants were evaluated in RAW264.7 cells infected with 1 × 106 CFU of M5-90Δirr, M5-90ΔrirA, or M5-90. We also tested the sensitivity of cells to hydrogen peroxide and their ability to grow. In addition, the virulence of these two mutants was evaluated in BALB/c mice. The results showed that the ability of these two mutants to invade and adhere inside the murine macrophages RAW264.7 was attenuated but their ability to replicate intracellularly was strengthened, enhancing the resistance to hydrogen peroxide. The M5-90Δirr mutant showed stronger growth ability than the parental strain under iron-limiting conditions. No differences were observed in the number of bacteria in spleen between M5-90 and M5-90Δirr at 7 or 15 days postinfection. However, the number of M5-90ΔrirA in spleen reduced significantly at 15 days postinfection. The splenic index of the M5-90Δirr group is evidently lower than that of M5-90. This is the first report that irr and rirA genes of B. melitensis are associated not only with virulence but also with growth ability. Together, our data suggest that M5-90Δirr is a promising Brucella vaccine candidate.
Subject(s)
Bacterial Proteins/genetics , Brucella melitensis/genetics , Brucella melitensis/pathogenicity , Gene Expression Regulation, Bacterial/physiology , Iron/metabolism , Transcription Factors/genetics , Animals , Anti-Infective Agents, Local/toxicity , Blotting, Western , Brucella Vaccine/immunology , Brucellosis/prevention & control , Colony Count, Microbial , Female , Hydrogen Peroxide/toxicity , Macrophages/microbiology , Mice , Mice, Inbred BALB C , Spleen/microbiology , Virulence/geneticsABSTRACT
Salmonellosis is a highly contagious bacterial disease that threatens both human and poultry health. Tests that can detect Salmonella in the field are urgently required to facilitate disease control and for epidemiological investigations. Here, we combined loop-mediated isothermal amplification (LAMP) with a chromatographic lateral flow dipstick (LFD) to rapidly and accurately detect Salmonella. LAMP primers were designed to target the Salmonella invA gene. LAMP conditions were optimized by adjusting the ratio of inner to outer primers, MgSO4 concentration, dNTP mix concentration, amplification temperature, and amplification time. We evaluated the specificity of our novel LAMP-LFD method using six Salmonella species and six related non-Salmonella strains. All six of the Salmonella strains, but none of the non-Salmonella strains, were amplified. LAMP-LFD was sensitive enough to detect concentrations of Salmonella enterica subsp. enterica serovar Pullorum genomic DNA as low as 89 fg/µl, which is 1,000 times more sensitive than conventional PCR. When artificially contaminated feed samples were analyzed, LAMP-LFD was also more sensitive than PCR. Finally, LAMP-LFD gave no false positives across 350 chicken anal swabs. Therefore, our novel LAMP-LFD assay was highly sensitive, specific, convenient, and fast, making it a valuable tool for the early diagnosis and monitoring of Salmonella infection in chickens.