Biotransformation and metabolite activity analysis of flavonoids from propolis in vivo.

Propolis is a natural resinous compound produced by bees, mixed with their saliva and wax, and has a range of biological benefits, including antioxidant and anti-inflammatory effects. This article reviews the in vivo transformation of propolis flavonoids and their potential influence on drug efficacy. Despite propolis is widely used, there is little research on how the active ingredients of propolis change in the body and how they interact with drugs. Future research will focus on these interactions and the metabolic fate of propolis in vivo.

An innovative molecular approach towards the cost-effective entomological authentication of honey.

Honey authentication and traceability are crucial not only for economic purposes but also for ensuring safety. However, the widespread adoption of cutting-edge technologies in practical applications has been hampered by complex, time-consuming sample pre-treatment processes, the need for skilled personnel, and substantial associated expenses. This study aimed to develop a simple and cost-effective molecular technique to verify the entomological source of honey. By utilizing newly designed primers, we successfully amplified the mitochondrial 16S ribosomal RNA gene of honey bees from honey, confirming the high quality of the extracted DNA. Employing RFLP analysis with AseI endonuclease, species-specific restriction patterns were generated for honey derived from six closely related honey bees of the Apis genus. Remarkably, this method was proven equally effective in identifying heat-treated and aged honey by presenting the same RFLP profiles as raw honey. As far as we know, this is the initial research of the simultaneous differentiation of honey from closely related honey bee species using the restriction endonuclease AseI and mitochondrial 16S rRNA gene fragments. As a result, it holds tremendous potential as a standardized guideline for regulatory agencies to ascertain the insect origins of honey and achieve comprehensive traceability.

Optimization of ultrasound-assisted extraction of fatty acids from royal jelly and its effect on the structural and antioxidant property.

Fatty acids are the key active components in royal jelly (RJ) with various biological activities. In this study, a novel ultrasound-assisted extraction (UAE) method was established to extract fatty acids from RJ and their structural and antioxidant property were further evaluated. The optimum extraction conditions were as follows: liquid-to-solid ratio of 10:1, ultrasonic power of 450 W and ultrasonic duration of 20 min, resulting in a better extraction yield of 16.48 % and 10-hydroxy-2(E)-decenoic acid (10-HDA) content of 4.12 %. Furthermore, compared with the solvent extraction method, the antioxidant activity of extract by ultrasound was enhanced significantly by at least 448 %. GC-MS showed that ultrasound didn't change the chemical composition of fatty acids, while it significantly increased the content of fatty acids. SEM image illustrated that extracts by UAE showed a rougher, looser microstructure compared to the solvent method. Overall, UAE is a promising method to obtain fatty acids in RJ with high efficiency.

Population Structure, Demographic History, and Adaptation of Giant Honeybees in China Revealed by Population Genomic Data.

There have been many population-based genomic studies on human-managed honeybees (Apis mellifera and Apis cerana), but there has been a notable lack of analysis with regard to wild honeybees, particularly in relation to their evolutionary history. Nevertheless, giant honeybees have been found to occupy distinct habitats and display remarkable characteristics, which are attracting an increased amount of attention. In this study, we de novo sequenced and then assembled the draft genome sequence of the Himalayan giant honeybee, Apis laboriosa. Phylogenetic analysis based on genomic information indicated that A. laboriosa and its tropical sister species Apis dorsata diverged ∼2.61 Ma, which supports the speciation hypothesis that links A. laboriosa to geological changes throughout history. Furthermore, we re-sequenced A. laboriosa and A. dorsata samples from five and six regions, respectively, across their population ranges in China. These analyses highlighted major genetic differences for Tibetan A. laboriosa as well as the Hainan Island A. dorsata. The demographic history of most giant honeybee populations has mirrored glacial cycles. More importantly, contrary to what has occurred among human-managed honeybees, the demographic history of these two wild honeybee species indicates a rapid decline in effective population size in the recent past, reflecting their differences in evolutionary histories. Several genes were found to be subject to selection, which may help giant honeybees to adapt to specific local conditions. In summary, our study sheds light on the evolutionary and adaptational characteristics of two wild giant honeybee species, which was useful for giant honeybee conservation.

Genomic signatures underlying the oogenesis of the ectoparasitic mite Varroa destructor on its new host Apis mellifera.

INTRODUCTION: Host shift of parasites may have devastating effects on the novel hosts. One remarkable example is that of the ectoparasitic mite Varroa destructor, which has shifted its host from Eastern honey bees (Apis cerana) to Western honey bees (Apis mellifera) and posed a global threat to apiculture. OBJECTIVES: To identify the genetic factors underlying the reproduction of host-shifted V. destructor on the new host. METHODS: Genome sequencing was conducted to construct the phylogeny of the host-shifted and non-shifted mites and to screen for genomic signatures that differentiated them. Artificial infestation experiment was conducted to compare the reproductive difference between the mites, and transcriptome sequencing was conducted to find differentially expressed genes (DEGs) during the reproduction process. RESULTS: The host-shifted and non-shifted V. destructor mites constituted two genetically distinct lineages, with 15,362 high-FST SNPs identified between them. Oogenesis was upregulated in host-shifted mites on the new host A. mellifera relative to non-shifted mites. The transcriptomes of the host-shifted and non-shifted mites differed significantly as early as 1h post-infestation. The DEGs were associated with nine genes carrying nonsynonymous high-FST SNPs, including mGluR2-like, Lamb2-like and Vitellogenin 6-like, which were also differentially expressed, and eIF4G, CG5800, Dap160 and Sas10, which were located in the center of the networks regulating the DEGs based on protein-protein interaction analysis. CONCLUSIONS: The annotated functions of these genes were all associated with oogenesis. These genes appear to be the key genetic determinants of the oogenesis of host-shifted mites on the new host. Further study of these candidate genes will help elucidate the key mechanism underlying the success of host shifts of V. destructor.

Design, Synthesis and Molecular Docking of 1,3,4-Oxadiazole-2(3H)-thione Derivatives Containing 1,4-Benzodioxane Skeleton as Potential FabH Inhibitors.

Fatty acid biosynthesis is essential for bacterial survival. Of these promising targets, ß-ketoacyl-acyl carrier protein (ACP) synthase III (FabH) is the most attractive target. A series of novel 1,3,4-oxadiazole-2(3H)-thione derivatives containing 1,4-benzodioxane skeleton targeting FabH were designed and synthesized. These compounds were determined by 1 H-NMR, 13 C-NMR, MS and further confirmed by crystallographic diffraction study for compound 7m and 7n. Most of the compounds exhibited good inhibitory activity against bacteria by computer-assisted screening, antibacterial activity test and E. coli FabH inhibitory activity test, wherein compounds 7e and 7q exhibited the most significant inhibitory activities. Besides, compound 7q showed the best E. coli FabH inhibitory activity (IC50 =2.45 µΜ). Computational docking studies also showed that compound 7q interacts with FabH critical residues in the active site.

Genetic divergence and functional convergence of gut bacteria between the Eastern honey bee Apis cerana and the Western honey bee Apis mellifera.

Introduction: The functional relevance of intra-species diversity in natural microbial communities remains largely unexplored. The guts of two closely related honey bee species, Apis cerana and A. mellifera, are colonised by a similar set of core bacterial species composed of host-specific strains, thereby providing a good model for an intra-species diversity study. Objectives: We aim to assess the functional relevance of intra-species diversity of A. cerana and A. mellifera gut microbiota. Methods: Honey bee workers were collected from four regions of China. Their gut microbiomes were investigated by shotgun metagenomic sequencing, and the bacterial compositions were compared at the species level. A cross-species colonisation assay was conducted, with the gut metabolomes being characterised by LC-MS/MS. Results: Comparative analysis showed that the strain composition of the core bacterial species was host-specific. These core bacterial species presented distinctive functional profiles between the hosts. However, the overall functional profiles of the A. cerana and A. mellifera gut microbiomes were similar; this was further supported by the consistency of the honey bees' gut metabolome, as the gut microbiota of different honey bee species showed rather similar metabolic profiles in the cross-species colonisation assay. Moreover, this experiment also demonstrated that the gut microbiota of A. cerana and A. mellifera could cross colonise between the two honey bee species. Conclusion: Our findings revealed functional differences in most core gut bacteria between the guts of A. cerana and A. mellifera, which may be associated with their inter-species diversity. However, the functional profiles of the overall gut microbiomes between the two honey bee species converge, probably as a result of the overlapping ecological niches of the two species. Our findings provide critical insights into the evolution and functional roles of the mutualistic microbiota of honey bees and reveal that functional redundancy could stabilise the gene content diversity at the strain-level within the gut community.

Combined royal jelly 10-hydroxydecanoic acid and aspirin has a synergistic effect against memory deficit and neuroinflammation.

Alzheimer's disease (AD), the most common form of neurodegenerative dementia among the older population, is associated with acute or chronic inflammation. As a nonsteroidal anti-inflammatory drug, aspirin has recently been widely studied in the prevention and treatment of neurodegenerative diseases. However, there is a controversy about the efficacy as well as the adverse effects of aspirin. 10-Hydroxydecanoic acid (10-HDAA) is a characteristic fatty acid found in the honey bee product royal jelly. In this study, we found that 10-HDAA attenuated the activation of the NF-κB pathway, then targeted Ptgs-1/2, the well-known target of aspirin. Hence, combined therapy of 10-HDAA and aspirin was conducted. In vitro assays suggested that this combinatory group alleviated LPS-induced inflammation in BV-2 cells, as assessed by the downregulation of nitric oxide, COX-2, and IL-6 compared to 10-HDAA or aspirin treatment alone. In vivo assays showed that the combined treatment synergistically inhibited the overactivation of glial cells and decreased the levels of pro-inflammatory mediators. Moreover, 10-HDAA alleviated the adverse effects of aspirin on gastrointestinal injuries and microbiota dysbiosis. The Morris water maze test indicated that neither 10-HDAA nor aspirin effectively improved LPS-induced memory dysfunction, but the combined therapy showed synergistic effects. Altogether, our findings support 10-HDAA and aspirin combinatory therapy as the basis for future therapeutics for AD and other neuroinflammation-related diseases with minimal adverse effects.

Complete digestion/biodegradation of polystyrene microplastics by greater wax moth (Galleria mellonella) larvae: Direct in vivo evidence, gut microbiota independence, and potential metabolic pathways.

Biodegradation of plastic polymers by plastic-eating insects such as the greater wax moth (Galleria mellonella) might be promising for reducing plastic pollution, but direct in vivo evidence along with the related metabolic pathways and role of gut microbiota require further investigation. In this study, we investigated the in vivo degradation process, underlying potential metabolic pathways, and involvement of the gut microbiota in polystyrene (PS) biodegradation via enforcing injection of G. mellonella larvae (Tianjin, China) with PS microbeads (0.5 mg/larva; Mn: 540 and Mw: 550) and general-purpose PS powders (2.5 mg/larva; Mn: 95,600 and Mw: 217,000). The results indicated that the PS microplastics were depolymerized and completely digested independent of gut microbiota in G. mellonella although the metabolism could be enhanced by gut microbiota. Based on comparative metabolomic and liquid chromatography analyses, we proposed two potential metabolic pathways of PS in the intestine of G. mellonella larvae: the styrene oxide-phenylacetaldehyde and 4-methylphenol-4-hydroxybenzaldehyde-4-hydroxybenzoate pathways. These results suggest that the enzymes of G. mellonella are responsible for the efficient biodegradation of PS. Further study is needed to identify these enzymes and investigate the underlying catalytic mechanisms.

Investigation of the Maturity Evaluation Indicator of Honey in Natural Ripening Process: The Case of Rape Honey.

Honey maturity, a critical factor for quality evaluation, is difficult to detect in the current industry research. The objective of this study was to explore the changes in the composition and find potential maturity indicators of rape honey at different maturity stages through evaluating physicochemical parameters (moisture, sugars, pH, electrical conductivity, total protein, total phenols, total flavonoids, proline, and enzyme activity), the antioxidant capacity, and volatile components. The relevant results are as follows: 1. As the maturity increased, the moisture, sucrose, and maltose content of rape honey gradually decreased, while the glucose, fructose, and total protein content gradually increased. The activities of diastase, invertase, and ß-glucosidase showed a significant increase with the elevation of ripening days, and the activity of glucose oxidase reached the highest before completely capping. 2. The antioxidant capacity of honey increased with the increase in honey maturity. There is a significant and strong correlation between the bioactive components of rape honey and antioxidant capacity (p < 0.01, |r| > 0.857). 3. Thirty-five volatile components have been identified. Nonanal, benzaldehyde monomer, and benzaldehyde dimer can be used as potential indicators for the identification of honey maturity stages. Principal component analysis (PCA) based on antioxidant parameters and volatile components can identify the maturity of honey.

Royal Jelly Proteins and Their Derived Peptides: Preparation, Properties, and Biological Activities.

Royal jelly, also called bee milk, is a source of high-quality proteins. Royal jelly proteins serve as not only a rich source of essential amino acids and functional donors but also an excellent substrate for preparing bioactive peptides. Most naturally occurring bioactive peptides in royal jelly are antibacterial, while peptides derived from proteolytic reactions are shown to exert antihypertensive, antioxidative, and anti-aging activities. Further studies are warranted to characterize the functional properties of major royal jelly proteins and peptides, to explore the preparation of bioactive peptides and the potential novel activities, to improve their bioavailability, to enhance the production efficiency for commercial availability, and finally to open up new applications for royal jelly as a functional food and potential therapeutic agent.

Population genetics and host specificity of Varroa destructor mites infesting eastern and western honeybees.

In a globalized world, parasites are often brought in contact with new potential hosts. When parasites successfully shift host, severe diseases can emerge at a large cost to society. However, the evolutionary processes leading to successful shifts are rarely understood, hindering risk assessment, prevention, or mitigation of their effects. Here, we screened populations of Varroa destructor, an ectoparasitic mite of the honeybee genus Apis, to investigate their genetic structure and reproductive potential on new and original hosts. From the patterns identified, we deduce the factors that influenced the macro- and microevolutionary processes that led to the structure observed. Among the mite variants identified, we found two genetically similar populations that differed in their reproductive abilities and thus in their host specificity. These lineages could interbreed, which represents a threat due to the possible increased virulence of the parasite on its original host. However, interbreeding was unidirectional from the host-shifted to the nonshifted native mites and could thus lead to speciation of the former. The results improve our understanding of the processes affecting the population structure and evolution of this economically important mite genus and suggest that introgression between shifted and nonshifted lineages may endanger the original host. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10340-020-01322-7.

Chemical Analyses and Antimicrobial Activity of Nine Kinds of Unifloral Chinese Honeys Compared to Manuka Honey (12+ and 20+).

Honey has good antimicrobial properties and can be used for medical treatment. The antimicrobial properties of unifloral honey varieties are different. In this study, we evaluated the antimicrobial and antioxidant activities of nine kinds of Chinese monofloral honeys. In addition, headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) technology was used to detect their volatile components. The relevant results are as follows: 1. The agar diffusion test showed that the diameter of inhibition zone against Staphylococcus aureus of Fennel honey (21.50 ± 0.41 mm), Agastache honey (20.74 ± 0.37 mm), and Pomegranate honey (18.16 ± 0.11 mm) was larger than that of Manuka 12+ honey (14.27 ± 0.10 mm) and Manuka 20+ honey (16.52 ± 0.12 mm). The antimicrobial activity of Chinese honey depends on hydrogen peroxide. 2. The total antioxidant capacity of Fennel honey, Agastache honey, and Pomegranate honey was higher than that of other Chinese honeys. There was a significant positive correlation between the total antioxidant capacity and the total phenol content of Chinese honey (r = 0.958). The correlation coefficient between the chroma value of Chinese honey and the total antioxidant and the diameter of inhibition zone was 0.940 and 0.746, respectively. The analyzed dark honeys had better antimicrobial and antioxidant activities. 3. There were significant differences in volatile components among Fennel honey, Agastache honey, Pomegranate honey, and Manuka honey. Hexanal-D and Heptanol were the characteristic components of Fennel honey and Pomegranate honey, respectively. Ethyl 2-methylbutyrate and 3-methylpentanoic acids were the unique compounds of Agastache honey. The flavor fingerprints of the honey samples from different plants can be successfully built using HS-GC-IMS and principal component analysis (PCA) based on their volatile compounds. Fennel honey, Agastache honey, and Pomegranate honey are Chinese honey varieties with excellent antimicrobial properties, and have the potential to be developed into medical grade honey.

Chinese Propolis Suppressed Pancreatic Cancer Panc-1 Cells Proliferation and Migration via Hippo-YAP Pathway.

Pancreatic cancer is one of the most malignant cancers with high mortality. Therefore, it is of great urgency to develop new agents that could improve the prognosis of Pancreatic cancer patients. Chinese propolis (CP), a flavonoid-rich beehive product, has been reported to have an anticancer effect. In this study, we applied CP to the human Pancreatic cancer cell line Panc-1 to verify its impact on tumor development. CP induced apoptosis in Panc-1 cells from 12.5 µg/mL in a time- and dose-dependent manner with an IC50 value of approximately 50 µg/mL. Apoptosis rate induced by CP was examined by Annexing FITC/PI assay. We found that 48 h treatment with 50 µg/mL CP resulted in 34.25 ± 3.81% apoptotic cells, as compared to 9.13 ± 1.76% in the control group. We further discovered that the Panc-1 cells tended to be arrested at G2/M phase after CP treatment, which is considered to contribute to the anti-proliferation effect of CP. Furthermore, our results demonstrated that CP suppressed Panc-1 cell migration by regulating epithelial-mesenchymal transition (EMT). Interestingly, the Hippo pathway was activated in Panc-1 cells after CP treatment, serving as a mechanism for the anti-pancreatic cancer effect of CP. These findings provide a possibility of beehive products as an alternative treatment for pancreatic cancer.

Anti-PD-1 Immunotherapy and Bee Venom for Relapsed and Refractory Liposarcoma: A Case Report.

Cancer immunotherapies, including immune checkpoint inhibitors, elicit long-term clinical responses but many cancer patients do not respond. Intensive efforts are therefore underway to identify additional immune pathways that may be modulated to enhance the efficacy of existing immunotherapies. Bee venom strongly stimulates the immune system, and is used as a complementary therapy to treat cancer pain in patients with advanced tumors in China. Bee venom contains several allergenic protease inhibitors and peptides. It triggers hypersensitivity reactions; that is, it is an immune system agonist. The generation of a spontaneous T cell response against tumor-associated antigens requires innate immune activation; this drives type I interferon production. We report a patient with a relapsed and refractory liposarcoma who had undergone several operations, chemotherapies, and radiotherapies. The tumor was large. The patient had attained the maximum radiation exposure dose. The tumor was resistant to chemotherapy and was infiltrating the pericardium, lungs, and diaphragm. The patient was a poor candidate for resection. He thus received apitherapy (a combination of bee venom and acupuncture) to control pain; then apatinib (an anti-angiogenic drug) was given to inhibit tumor growth but was terminated early because the patient could not tolerate the side effects. Subsequently, a programmed death 1 inhibitor was combined with apitherapy. Bee venom served as an innate immune system agonist promoting immune cell priming and recruitment in the tumor microenvironment. The patient was finally able to undergo radical liposarcoma resection, and no evidence of recurrence was found at re-examination 16 months after surgery.

A New Strain of Virus Discovered in China Specific to the Parasitic Mite Varroa destructor Poses a Potential Threat to Honey Bees.

The ectoparasitic mite, Varroa destructor, feeds directly on honey bees and serves as a vector for transmitting viruses among them. The Varroa mite causes relatively little damage to its natural host, the Eastern honey bee (Apis cerana) but it is the most devastating pest for the Western honey bee (Apis mellifera). Using Illumina HiSeq sequencing technology, we conducted a metatranscriptome analysis of the microbial community associated with Varroa mites. This study led to the identification of a new Chinese strain of Varroa destructor virus-2 (VDV-2), which is a member of the Iflaviridae family and was previously reported to be specific to Varroa mites. A subsequent epidemiological investigation of Chinese strain of VDV-2 (VDV-2-China) showed that the virus was highly prevalent among Varroa populations and was not identified in any of the adult workers from both A. mellifera and A.cerana colonies distributed in six provinces in China, clearly indicating that VDV-2-China is predominantly a Varroa-adapted virus. While A. mellifera worker pupae exposed to less than two Varroa mites tested negative for VDV-2-China, VDV-2-China was detected in 12.5% of the A. mellifera worker pupae that were parasitized by more than 10 Varroa mites, bringing into play the possibility of a new scenario where VDV-2 could be transmitted to the honey bees during heavy Varroa infestations. Bioassay for the VDV-2-China infectivity showed that A. cerana was not a permissive host for VDV-2-China, yet A. mellifera could be a biological host that supports VDV-2-China's replication. The different replication dynamics of the virus between the two host species reflect their variation in terms of susceptibility to the virus infection, posing a potential threat to the health of the Western honey bee. The information gained from this study contributes to the knowledge concerning genetic variabilities and evolutionary dynamics of Varroa-borne viruses, thereby enhancing our understanding of underlying molecular mechanisms governing honey bee Varroosis.

Propolis ameliorates restenosis in hypercholesterolemia rabbits with carotid balloon injury by inhibiting lipid accumulation, oxidative stress, and TLR4/NF-κB pathway.

Neointima formation and atherosclerosis are the main complications after the endovascular intervention and vascular surgery, and there are no effective drugs. Propolis is a kind of resin substance produced by honeybees and has numerous health-beneficial effects. In this study, we evaluated the effects of propolis (125 and 250 mg·kg-1 ·day-1 , 6 weeks) on carotid restenosis in hypercholesterolemia rabbits. Propolis significantly ameliorated the degree of carotid restenosis, inhibited neointima hyperplasia, reduced serum lipids profile, and enhanced the anti-oxidative activities in hypercholesterolemia rabbits. Furthermore, propolis reduced the plasma levels of C-reactive protein, interleukin-6, and tumor necrosis factor-α (TNF-α), and inhibited the expression of CD68, TLR4, NF-κB p65, MMP-9, and TNF-α in the carotid arteries. The results indicate that propolis has a protective effect on carotid restenosis in rabbits, which is associated with regulating blood lipids, inhibiting oxidative stress and inflammation, and its anti-inflammatory activity may be related to inhibit TLR4-mediated NF-κB signaling pathway. PRACTICAL APPLICATIONS: Restenosis is a primary challenge in angioplasty and atherosclerotic treatment. Hyperlipidemia can induce inflammation and accelerate the formation of restenosis. Recently, natural products have been widely used to prevent intimal hyperplasia of common cardiovascular diseases. Propolis is currently a popular functional food, but the role of propolis on carotid restenosis after angioplasty and its underlying mechanism remains unclear. This study showed that propolis inhibits the effect of carotid restenosis in hypercholesterolemia rabbits. The results of this study may provide a basis for propolis to prevent and treat vascular restenosis.

Seasonal variation of viral infections between the eastern honey bee (Apis cerana) and the western honey bee (Apis mellifera).

It is a widespread practice in China to keep colonies of both the western honey bee, Apis mellifera, and the eastern honey bee, Apis cerana, in close proximity. However, this practice increases opportunities for spillover of parasites and pathogens between the two host bee species, impacting spatial and temporal patterns in the occurrence and prevalence of the viruses that adversely affect bee health. We conducted a 1-year large-scale survey to assess the current status of viral infection in both A. mellifera and A. cerana in China. Our study focused on multiple aspects of viral infections in honey bees, including infection rate, viral load, seasonal variation, regional variation, and phylogenetic relationships of the viruses within the same species found in this study and other parts of the world. The survey showed that the black queen cell virus (BQCV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), and sacbrood virus (SBV) were common in both A. mellifera and A. cerana, and infection dynamics of BQCV, DWV, and SBV between bee species or seasons were significantly different. DWV was the most common virus in A. mellifera, and its infection rate and load in A. mellifera were higher than those in A. cerana, which reflects the high susceptibility of A. mellifera to Varroa destructor infestation. The infection rate and viral load of SBV were higher in A. cerana than in A. mellifera, indicating that SBV poses a greater threat to A. cerana than to A. mellifera. Our results also suggested that there was no geographical variation in viral dynamics in A. mellifera and A. cerana. Phylogenetic analyses of BQCV, DWV, IAPV, and SBV suggested the cross-regional and cross-species spread of these viruses. This study provides important insights into the complex relationships between viruses and their hosts in different seasons and regions, which will be important for developing effective disease management strategies to improve bee health.

The Pass-on Effect of Tetracycline-Induced Honey Bee (Apis mellifera) Gut Community Dysbiosis.

Gut microbial community plays an important role in the regulation of insect health. Antibiotic treatment is powerful to fight bacterial infections, while it also causes collateral damage to gut microbiome, which may have long-lasting consequences for host health. However, current studies on honey bees mainly focus on the impact of direct exposure to antibiotics on individual bees, and little is known about the impact of social transmission of antibiotic-induced gut community disorder in honey bee colonies. In order to provide insight into the potential pass-on effect of antibiotic-induced dysbiosis, we colonized newly emerged germ-free workers with either normal or tetracycline-treated gut community and analyzed the gut bacteria composition. We also treated workers with low dosage of tetracycline to evaluate its impact on honey bee gut microbiota. Our results showed that the tetracycline-treated gut community caused disruption of gut community in their receivers, while the direct exposure to the low dosage of tetracycline had no significant effect. In addition, no significant difference was observed on the mortality rate of A. mellifera workers with different treatments. These results suggest that though the residue of antibiotic treatment may not have direct effect on honey bee gut community, the gut microbiota dysbiosis caused by high dosage of antibiotic treatment has a cascade effect on the gut community of the nestmates in honeybee colonies.

Unique dynamic mode between Artepillin C and human serum albumin implies the characteristics of Brazilian green propolis representative bioactive component.

As a representative bioactive component in Brazil green propolis, Artepillin C (ArtC; 3, 5-diprenyl-4-hydroxycinnamic acid) has been reported a wide variety of physiological activities including anti-tumor, anti-inflammatory, and antimicrobial activity etc. However, it seems incompatible that ArtC in vivo was characterized as low absorption efficiency and low bioavailability. In order to obtain the elucidation, we further investigated the physicochemical basis of ArtC interacting with human serum albumin (HSA) in vitro. We found a unique dynamic mode interaction between ArtC and HSA, which is completely different from other reported propolis bioactive components. Thermodynamic analysis showed that hydrophobic interactions and electrostatic forces are the main driving force. The competitive assay indicates that the binding site of ArtC with HSA is close to the Sudlow's site I. The findings of this study reveal the unique physicochemical transport mechanism of ArtC in the human body, which helps to further understand the uniqueness of the representative functional components of Brazilian green propolis in the human body.