Gut microbiota-driven regulation of queen bee ovarian metabolism.

With the global prevalence of Varroa mites, more and more beekeepers resort to confining the queen bee in a queen cage to control mite infestation or to breed superior and robust queen bees. However, the impact of such practices on the queen bee remains largely unknown. Therefore, we subjected the queen bees to a 21-day egg-laying restriction treatment (from the egg stage to the emergence of adult worker bees) and analyzed the queen bees' ovarian metabolites and gut microbiota after 21 days, aiming to assess the queen bees' quality and assist beekeepers in better hive management. Our findings revealed a significant reduction in the relative expression levels of Vg and Hex110 genes in the ovaries of egg laying-restricted queen bees compared to unrestricted egg-laying queens. The diversity of gut microbiota in the queen bee exhibited a notable decrease, accompanied by corresponding changes in the core bacteria of the microbial community, the relative abundance of Lactobacillus and Bifidobacterium increased from 22.34% to 53.14% (P = 0.01) and from 0.053% to 0.580% (P = 0.04), respectively. The relative abundance of Bombella decreased from 25.85% to 1.720% (P = 0.002). Following egg-laying restriction, the activity of the queen bee's ovaries decreased, while the metabolism of glycerophospholipids remained or stored more lipid molecules, awaiting environmental changes for the queen bee to resume egg laying promptly. Furthermore, we observed that Bombella in the queen bee's gut may regulate the queen's ovarian metabolism through tryptophan metabolism. These findings provide novel insights into the interplay among queen egg laying, gut microbiota, and ovarian metabolism. IMPORTANCE With Varroa mite infestation, beekeepers often confine the queen bee in cages for control or breeding. However, the impact on the queen bee is largely unknown. We evaluated queen bee quality by restricting egg laying and analyzing ovarian metabolites and gut microbiota. In this study, we provided a comprehensive explanation of the expression of ovarian genes, the diversity of gut microbiota, and changes in ovarian metabolism in the queen bee. Through integrated analysis of the queen bee's gut microbiota and ovarian metabolism, we discovered that the gut microbiota can regulate the queen bee's ovarian metabolism. These findings provide valuable insights into the interplay among egg laying, gut microbiota, and the reproductive health of the queen bee. Understanding these relationships can contribute to the development of better strategies for Varroa mite control and queen bee breeding.

Swine-manure composts induce the enrichment of antibiotic-resistant bacteria but not antibiotic resistance genes in soils.

Composting is a common and effective strategy for reducing antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) from animal manure. However, it is unclear whether the advantages of composting for the control of ARGs and ARB can be further increased in land application. This study investigated the fate of ARB and ARGs after land application of swine-manure composts (SMCs) to three different soil types (red soil, loess and black soil). The results showed that although the SMCs caused an increase in the abundance of total ARGs in the soil in the short period, they significantly reduced (p < 0.01) the abundance of total ARGs after 82 days compared to the control. The decay rate of ARGs reflected by the half-life times (t1/2) varied by soil type, with red soil being the longest. The SMCs mainly introduced ermF, tetG and tetX into the soils, while these ARGs quickly declined to the control level. Notably, SMCs increased the number of ARB in the soils, especially for cefotaxime-resistant bacteria. Although SMCs only affected the microbiome significantly during the early stage (p < 0.05), it took a much longer time for the microbiome to recover compared to the control. Statistical analysis indicated that changes in the microbial community contributed more to the fate of ARGs during SMCs land application than other factors. Overall, it is proposed that the advantages of ARGs control in the composting process for swine manure can be further increased in land application, but it can still bring some risks in regard to ARB.

Gut microbiome helps honeybee (Apis mellifera) resist the stress of toxic nectar plant (Bidens pilosa) exposure: Evidence for survival and immunity.

Honeybee (Apis mellifera) ingestion of toxic nectar plants can threaten their health and survival. However, little is known about how to help honeybees mitigate the effects of toxic nectar plant poisoning. We exposed honeybees to different concentrations of Bidens pilosa flower extracts and found that B. pilosa exposure significantly reduced honeybee survival in a dose-dependent manner. By measuring changes in detoxification and antioxidant enzymes and the gut microbiome, we found that superoxide dismutase, glutathione-S-transferase and carboxylesterase activities were significantly activated with increasing concentrations of B. pilosa and that different concentrations of B. pilosa exposure changed the structure of the honeybee gut microbiome, causing a significant reduction in the abundance of Bartonella (p < 0.001) and an increase in Lactobacillus. Importantly, by using Germ-Free bees, we found that colonization by the gut microbes Bartonella apis and Apilactobacillus kunkeei (original classification as Lactobacillus kunkeei) significantly increased the resistance of honeybees to B. pilosa and significantly upregulated bee-associated immune genes. These results suggest that honeybee detoxification systems possess a level of resistance to the toxic nectar plant B. pilosa and that the gut microbes B. apis and A. kunkeei may augment resistance to B. pilosa stress by improving host immunity.

Pricing extreme mortality risk in the wake of the COVID-19 pandemic.

In pricing extreme mortality risk, it is commonly assumed that interest rate and mortality rate are independent. However, the COVID-19 pandemic calls this assumption into question. In this paper, we employ a bivariate affine jump-diffusion model to describe the joint dynamics of interest rate and excess mortality, allowing for both correlated diffusions and joint jumps. Utilizing the latest U.S. mortality and interest rate data, we find a significant negative correlation between interest rate and excess mortality, and a much higher jump intensity when the pandemic experience is considered. Moreover, we construct a risk-neutral pricing measure that accounts for both diffusion and jump risk premia, and we solve for the market prices of risk based on mortality bond prices. Our results show that the pandemic experience can drastically change investors' perception of the mortality risk market in the post-pandemic era.

Honeybee (Apis mellifera) resistance to deltamethrin exposure by Modulating the gut microbiota and improving immunity.

Honeybees (Apis mellifera) are important economic insects and play important roles in pollination and maintenance of ecological balance. However, the use of pesticides has posed a substantial threat to bees in recent years, with the more widely used deltamethrin being the most harmful. In this study, we found that deltamethrin exposure significantly reduced bee survival in a dose-dependent manner (p = 0.025). In addition, metagenomic sequencing further revealed that DM exposure significantly reduced the diversity of the bee gut microbiota (Chao1, p < 0.0001; Shannon, p < 0.0001; Simpson, p < 0.0001) and decreased the relative abundance of core species of the gut microbiota. Importantly, in studies of GF-bees, we found that the colonization of important gut bacteria such as Gilliamella apicola and Lactobacillus kunkeei significantly increased bee resistance to DM (survival rate increased from 16.7 to 66.7%). Interestingly, we found that the immunity-genes Defensin-2 and Toll were significantly upregulated in bees after the colonization of gut bacteria. These results suggest that gut bacteria may protect against DM stress by improving host immunity. Our findings provide an important rationale for protecting honeybees from pollutants from the perspective of gut microbes.

Effects of spinetoram and glyphosate on physiological biomarkers and gut microbes in Bombus terrestris.

The sublethal effects of pesticide poisoning will have significant negative impacts on the foraging and learning of bees and bumblebees, so it has received widespread attention. However, little is known about the physiological effects of sublethal spinetoram and glyphosate exposure on bumblebees. We continuously exposed Bombus terrestris to sublethal (2.5 mg/L) spinetoram or glyphosate under controlled conditions for 10 days. The superoxide dismutase, glutathione-S-transferase, carboxylesterase, prophenoloxidase, α-amylase and protease activities, and changes in gut microbes were measured to understand the effects of sublethal pesticide exposure on the physiology and gut microbes of bumblebees. Sublethal pesticide exposure to significantly increased superoxide dismutase activity and significantly decreased gut α-amylase activity in bumblebees but had no significant effect on glutathione-S-transferase, carboxylesterase or gut protease activities. In addition, glyphosate increased the activity of prophenoloxidase. Interestingly, we observed that neither of the two pesticides had a significant effect on dominant gut bacteria, but glyphosate significantly altered the structure of the dominant gut fungal community, and reduced the relative abundance of Zygosaccharomyces associated with fat accumulation. These results suggest that sublethal spinetoram and glyphosate do not significantly affect the detoxification system of bumblebees, but may affect bumblebee health by inhibiting energy acquisition. Our results provide information on the sublethal effects of exposure to low concentrations of glyphosate and spinetoram on bumblebees in terms of physiology and gut microbes.

The composition of bacteria in gut and beebread of stingless bees (Apidae: Meliponini) from tropics Yunnan, China.

Stingless bees are the main pollinators in tropical and subtropical regions. However, there are only a few studies on the structure and composition of bacteria in the gut and beebread of stingless bees, especially in China. To address this shortage of information, we characterized the microbiota of three common species of stingless bees (Lepidotrigona terminata, Lepidotrigona ventralis and Tetragonula pagdeni) and beebread samples of T. pagdeni. The results showed that the gut of stingless bees contained a set of dominant bacteria, including Acetobacter-like, Snodgrassella, Lactobacillus, Psychrobacter, Pseudomonas, Bifidobacterium and other species. The gut microbiota structures of the three stingless bees were different, and the abundances of bacterial species in the gut varied between communities of the same bee species. The reasons for this are manifold and may include food preference, age and genetic differences. In addition, the abundances of Lactobacillus, Carnimonas, Escherichia-Shigella, Acinetobacter and other species were high in the beebread of stingless bees. In conclusion, our findings reveal the bacteria composition and structure of the gut and beebread of stingless bees in China and deepen our understanding of the dominant bacteria of the gut and beebread of stingless bees.

The Succession of the Gut Microbiota in Insects: A Dynamic Alteration of the Gut Microbiota During the Whole Life Cycle of Honey Bees (Apis cerana).

The Asian honey bee Apis cerana is a valuable biological resource insect that plays an important role in the ecological environment and agricultural economy. The composition of the gut microbiota has a great influence on the health and development of the host. However, studies on the insect gut microbiota are rarely reported, especially studies on the dynamic succession of the insect gut microbiota. Therefore, this study used high-throughput sequencing technology to sequence the gut microbiota of A. cerana at different developmental stages (0 days post emergence (0 dpe), 1 dpe, 3 dpe, 7 dpe, 12 dpe, 19 dpe, 25 dpe, 30 dpe, and 35 dpe). The results of this study indicated that the diversity of the gut microbiota varied significantly at different developmental stages (ACE, P = 0.045; Chao1, P = 0.031; Shannon, P = 0.0019; Simpson, P = 0.041). In addition, at the phylum and genus taxonomic levels, the dominant constituents in the gut microbiota changed significantly at different developmental stages. Our results also suggest that environmental exposure in the early stages of development has the greatest impact on the gut microbiota. The results of this study reveal the general rule of gut microbiota succession in the A. cerana life cycle. This study not only deepens our understanding of the colonization pattern of the gut microbiota in workers but also provides more comprehensive information for exploring the colonization of the gut microbiota in insects and other animals.

Bergenin Monohydrate Attenuates Inflammatory Response via MAPK and NF-κB Pathways Against Klebsiella pneumonia Infection.

Background: Klebsiella pneumonia has emerged as a critical pathogen causing severe clinical problems, such as pneumonia and sepsis. Meanwhile, intensified drug resistance induced by antibiotic therapy necessitates discovering novel and active molecules from Traditional Chinese Medicine (TCM) for treatment. Methods and results: In this study, the isolated Bergenin monohydrate showed an anti-inflammatory effect in Klebsiella-infected mice. We initially investigated the anti-inflammatory effects and cytoprotection against oxidative stress in vitro and in vivo. Interestingly, a specific dose of Bm can effectively ameliorate lung injury and suppress the expression of inflammatory cytokines such as TNF-α, IL-6, IL-1ß and PEG2. Moreover, Bm was also shown to reduced the levels of MPO, MDA and increased SOD and GSH activities. Moreover, we assessed the intracellular signaling molecules including p38, ERK, JNK, IκB, NF-κB-p65 by western blotting and verified through MAPK and NF-κB pathways inhibition experiments. These results reveal that Bm executed its effects via the classical MAPK signaling pathway and NF-κB pathway. Conclusion: Given its underlying anti-inflammatory effect, Bm may be used as a promising therapeutic against Klebsiella-induced infection, thus providing a benefit for the future clinical therapy of pneumonia and medicine design.

Protocatechuic aldehyde from Salvia miltiorrhiza exhibits an anti-inflammatory effect through inhibiting MAPK signalling pathway.

BACKGROUND: The aerial parts of Salvia miltiorrhiza, which was considered to be the waste part and discarded during the root harvest, is rich in protocatechuic aldehyde (PAI). This study investigated the health-promoting effects of extracts and PAI from the aerial parts of Salvia miltiorrhiza, including its anti-inflammatory effects and the underlying mechanisms of action in vitro and in vivo. METHOD: Purification of the sample paste of Salvia miltiorrhiza was accomplished using HPLC analysis. TheMTT (Methylthiazolyldiphenyl-tetrazolium bromide) assay was employed to determine the cell viability. The production of inflammatory factors was detected by ELISA assays. The histopathological analysis was used to analyse the lungs and livers of mice treated with PAI. Western blot was performed to reveal the mechanism of PAI in anti-inflammatory. RESULTS: The extracts and PAI from the aerial parts of Salvia miltiorrhiza inhibited TNF-α, IL-6 production and promoted the production of IL-10 in vivo in mice and in vitro in the macrophage cell line RAW264.7. NF-κB and MAPKs kinase phosphorylation were also suppressed by PAI in vivo and in vitro, indicating that PAI exhibited an anti-inflammatory effect. CONCLUSION: These findings suggest that the aerial parts of Salvia miltiorrhiza extract may serve as potential protective agents for inflammatory.

Comparative analysis of the gut microbiota of Apis cerana in Yunnan using high-throughput sequencing.

Gut microbes play an important role in host disease and health. The Asian honey bee Apis cerana is an important pollinator of agricultural crops in China. However, there are still few studies on the structure and composition of the microbiota in the intestine of A. cerana, especially A. cerana in Yunnan. To understand the species and composition of the microbiota in the intestine of A. cerana in Yunnan, we used high-throughput sequencing technology to carry out 16S rRNA sequencing on 50 samples from Kunming, Xishuangbanna and Mengzi. The results show that both from the phylum level and the genus level, the structure and abundance of the microbiota in the gut of A. cerana from the three regions tended to be the same. At the phylum level, the abundance of Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Acidobacteria and other species was high in A. cerana from different areas. At the genus level, the abundance of Lactobacillus, Gilliamella, Snodgrassella, Apibacter, Candidatus Schmidhempelia and other species was high in A. cerana from different areas. Due to its unique geographical environment and climatic conditions, at the genus level, the diversity of bacterial communities in Xishuangbanna was significantly lower than that in the other two regions, which was about 100 genera less. In conclusion, our results reveal the composition and structure of the intestinal microbiota of bees in Yunnan and deepen our understanding of the intestinal microbiota of bees.

Chlorogenic acid prevents vancomycin-induced nephrotoxicity without compromising vancomycin antibacterial properties.

Vancomycin (VCM) is an effective chemotherapeutic agent commonly used against gram-positive microorganisms but has serious nephrotoxic side effects that limit its effectiveness. New therapeutics and strategies are urgently needed to combat VCM associated nephrotoxicity. In this study, we determined the protective effect of chlorogenic acid (CA) in a rat model of VCM-induced nephrotoxicity. VCM administration led to markedly elevated blood urea nitrogen and serum creatinine levels that could be prevented with CA co-administration. VCM-mediated oxidative stress was also significantly attenuated by CA as reflected by decreased malondialdehyde and nitric oxide in VCM-treated kidneys. CA administration also prevented the VCM-mediated decrease in the renal antioxidative enzyme activities of glutathione reductase, glutathione peroxidase, and catalase and led to increased levels of reduced glutathione that had been depleted by VCM. Moreover, CA administration clearly inhibited VCM-induced expression of nuclear factor-kappa B, inducible nitric oxide synthase and the downstream pro-inflammatory mediators tumor necrosis factor-α and interleukins 1ß and 6. Apoptotic markers were also markedly down-regulated with CA. Overall, CA treatment mitigated VCM-induced oxidative and nitrosative stresses and countered the apoptotic and inflammatory effects of VCM. Notably, CA did not affect the antibacterial activity of VCM in vitro.

Mechanism of Synergy Between Tetracycline and Quercetin Against Antibiotic Resistant Escherichia coli.

Treatment of multi-drug resistant (MDR) Escherichia coli intestinal infections are being hampered by the presence of the mcr-1 (colistin) and tet (tetracycline) resistance genes in these strains. We screened seven traditional Chinese medicines for their ability to synergize with tetracycline to provide an effective new drug for the treatment of animal intestinal diseases caused by MDR E. coli. Our primary screen identified quercetin as a compound that reduced the minimum inhibitory concentration (MIC) of tetracycline against the E. coli standard test strain American Type Culture Collection (ATCC) 25922 and clinical isolates fourfold from 4 and 256 µg/mL to 1 and 64 µg/mL, respectively. Low levels of quercetin in combination with tetracycline were bactericidal for clinical E. coli isolates and after 24 h, the differences between this combination and each drug singly were 108 CFU/mL. We used this combination therapy in a mouse infection model and found 100% survival after 48 h compared with <50% for each drug alone. This drug combination also synergized to disrupt the bacterial cell envelope resulting in increased permeability and cell lysis. These data demonstrate that combinatorial screening at low concentrations constitutes an efficient approach to identify clinically relevant quercetin/tetracycline combinations and is a valuable prototypical combination that has a high clinical potential against E. coli infections.

Distribution and elimination of quinocetone and its major metabolites in Cherry Valley ducks.

We examined the tissue distribution and elimination of quinocetone (QCT) and its major metabolites 1-desoxyquinocetone (1-DQCT), di-desoxyquinocetone (BDQCT), and 3-methyl-quinoxaline-2-carboxylic (MQCA) in ducks. The analytes were simultaneously quantitated using a UPLC-MS/MS method after oral administration of QCT at 100 mg·kg-1 day-1 for 7 days. We found that QCT and its major metabolites were widely distributed in duck tissues. The concentrations indicated that the primary compound in the liver, kidney, and heart was MQCA and the primary compound in the stomach, intestine, spleen, and lung was QCT. We also identified that MQCA was the most appropriate compound for QCT residue monitoring. The liver and kidney are the primary QCT target organs in ducks, and this study provides clear monitoring tools and important data to evaluate its safety.

Rutin attenuates vancomycin-induced renal tubular cell apoptosis via suppression of apoptosis, mitochondrial dysfunction, and oxidative stress.

Vancomycin is a glycopeptide antibiotic widely used to treat infections caused by methicillin-resistant Staphylococcus aureus. However, nephrotoxicity is a major adverse side effect, and the development of effective nephroprotective agents remains a priority in antimicrobial chemotherapy. In this study, we investigated the cell protective effects of the flavonol glycoside rutin against vancomycin-induced toxicity. Vancomycin added to porcine renal tubular LLC-PK1 cells caused an increase of production of intracellular reactive oxygen species and subsequent apoptotic cell death. Pretreatment of LLC-PK1 cells with rutin at 5, 10, and 20 µM for 2 hr prior to 2-mM vancomycin exposure for 24 hr significantly decreased intracellular reactive oxygen species and increased superoxide dismutase and catalase activities. Rutin pretreatment also protected cells from vancomycin-induced caspase activation, mitochondrial membrane depolarization, and subsequent apoptosis. This study demonstrates a protective effect of rutin and suggests that rutin coadministration is an alternative therapy for treatment of vancomycin-induced nephrotoxicity.

Cefquinome-Loaded Microsphere Formulations in Protection against Pneumonia with Klebsiella pneumonia Infection and Inflammatory Response in Rats.

PURPOSE: This study aimed to compare in vivo activity between cefquinome (CEQ)-loaded poly lactic-co-glycolic acid (PLGA) microspheres (CEQ-PLGA-MS) and CEQ injection (CEQ-INJ) against Klebsiella pneumonia in a rat lung infection model. METHODS: Forty-eight rats were divided into control group (sham operated without infection and drug treatment), Klebsiella pneumonia model group (KPD + Saline), CEQ-PLGA-MS and CEQ-INJ therapy groups (KPD + CEQ-PLGA-MS and KPD + INJ, respectively). In the KPD + Saline group, rats were infected with Klebsiella pneumonia ATCC 10031. In the KPD + CEQ-PLGA-MS and KPD + INJ groups, infected rats were intravenously injected with 12.5 mg/kg body weight CEQ-PLGA-MS and CEQ-INJ, respectively. RESULTS: Compared to CEQ-INJ treatment group, CEQ-PLGA-MS treatment further decreased the number of bacteria colonies (decreased to 1.94 lg CFU/g) in lung tissues and the levels of inflammatory cytokine including tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, IL-4 (p < 0.05 or p < 0.01) in bronchoalveolar lavage fluid at 48 h. Consistently, a significant decreases of scores of inflammation severity were showed at 48 h in the KPD + CEQ-PLGA-MS treatment group, compared to the KPD + CEQ-INJ treatment group. CONCLUSION: Our results reveal that CEQ-PLGA-MS has the better therapeutic effect than CEQ-INJ for Klebsiella pneumonia lung infections in rats. The vehicle of CEQ-PLGA-MS as the promising alternatives to control the lung infections with the important pathogens.

Rutin Attenuates Vancomycin-Induced Nephrotoxicity by Ameliorating Oxidative Stress, Apoptosis, and Inflammation in Rats.

Nephrotoxicity is the major limiting factor for the clinical use of vancomycin (VCM) for treatment of serious infections caused by multiresistant Gram-positive bacteria. This study investigated the renal protective activity of rutin in a rat model of VCM-induced kidney injury in male Wistar rats. VCM administered intraperitoneally at 200 mg/kg twice daily for 7 successive days resulted in significant elevation of blood urea nitrogen and creatinine, as well as urinary N-acetyl-ß-D-glucosaminidase. Coadministration of VCM with oral rutin at 150 mg/kg significantly reduced these markers of kidney damage. Rutin also significantly attenuated VCM-induced oxidative stress, inflammatory cell infiltration, apoptosis, and decreased interleukin-1ß and tumor necrosis factor alpha levels (all P < 0.05 or 0.01) in kidneys. Renal recovery from VCM injury was achieved by rutin through increases in Nrf2 and HO-1 and a decrease in NF-κB expression. Our results demonstrated a protective effect of rutin on VCM-induced kidney injury through suppression of oxidative stress, apoptosis, and downregulation of the inflammatory response. This study highlights a role for oral rutin as an effective intervention to ameliorate nephrotoxicity in patients undergoing VCM therapy.

Kaempferol-3-O-glucorhamnoside inhibits inflammatory responses via MAPK and NF-κB pathways in vitro and in vivo.

Klebsiella pneumoniae causes severe infections including pneumonia and sepsis and treatments are complicated by increased levels of antibiotic resistance. We have identified a flavonoid kaempferol-3-O-glucorhamnoside derived from the plant Thesium chinense Turcz that possessed potent anti-inflammatory effects in K. pneumoniae infected mice. Administration of kaempferol-3-O-glucorhamnoside before bacterial challenge effectively suppressed expression of the major inflammatory cytokines TNF-α, IL-6, IL-1ß and PGE2 and ameliorated lung edema. In addition, administration of this compound to cultured RAW macrophages or Balb/c mice resulted in the suppression of NFκB and MAP kinase phosphorylation indicating an inhibitory effect on inflammation in vitro and in vivo. Kaempferol-3-O-glucorhamnoside also decreased ROS levels and overall oxidative stress in lungs and in cultured cells generated by K. pneumoniae exposure. Taken together, kaempferol-3-O-glucorhamnoside is a potent anti-inflammatory in vitro and in vivo and is a promising therapeutic agent for treating K. pneumoniae infections in the clinic.