Israeli acute paralysis virus (IAPV) is a widespread RNA virus of honey bees that has been linked with colony losses. Here we describe the transmission, prevalence, and genetic traits of this virus, along with host transcriptional responses to infections. Further, we present RNAi-based strategies for limiting an important mechanism used by IAPV to subvert host defenses. Our study shows that IAPV is established as a persistent infection in honey bee populations, likely enabled by both horizontal and vertical transmission pathways. The phenotypic differences in pathology among different strains of IAPV found globally may be due to high levels of standing genetic variation. Microarray profiles of host responses to IAPV infection revealed that mitochondrial function is the most significantly affected biological process, suggesting that viral infection causes significant disturbance in energy-related host processes. The expression of genes involved in immune pathways in adult bees indicates that IAPV infection triggers active immune responses. The evidence that silencing an IAPV-encoded putative suppressor of RNAi reduces IAPV replication suggests a functional assignment for a particular genomic region of IAPV and closely related viruses from the Family Dicistroviridae, and indicates a novel therapeutic strategy for limiting multiple honey bee viruses simultaneously and reducing colony losses due to viral diseases. We believe that the knowledge and insights gained from this study will provide a new platform for continuing studies of the IAPV–host interactions and have positive implications for disease management that will lead to mitigation of escalating honey bee colony losses worldwide.

It has become increasingly clear that gut bacteria play vital roles in the development, nutrition, immunity, and overall fitness of their eukaryotic hosts. We conducted the present study to investigate the effects of gut microbiota disruption on the honey bee’s immune responses to infection by the microsporidian parasite Nosema ceranae. Newly emerged adult workers were collected and divided into four groups: Group I—no treatment; Group II—inoculated with N. ceranae, Group III—antibiotic treatment, and Group IV—antibiotic treatment after inoculation with N. ceranae. Our study showed that Nosema infection did not cause obvious disruption of the gut bacterial community as there was no significant difference in the density and composition of gut bacteria between Group I and Group II. However, the elimination of gut bacteria by antibiotic (Groups III and IV) negatively impacted the functioning of the honey bees’ immune system as evidenced by the expression of genes encoding antimicrobial peptides abaecin, defensin1, and hymenoptaecin that showed the following ranking: Group I > Group II > Group III > Group IV. In addition, significantly higher Nosema levels were observed in Group IV than in Group II, suggesting that eliminating gut bacteria weakened immune function and made honey bees more susceptible to Nosema infection. Based on Group IV having displayed the highest mortality rate among the four experimental groups indicates that antibiotic treatment in combination with stress, associated with Nosema infection, significantly and negatively impacts honey bee survival. The present study adds new evidence that antibiotic treatment not only leads to the complex problem of antibiotic resistance but can impact honey bee disease resistance. Further studies aimed at specific components of the gut bacterial community will provide new insights into the roles of specific bacteria and possibly new approaches to improving bee health.

The aim of this study was to improve cage systems for maintaining adult honey bee (Apis mellifera L.) workers under in vitro laboratory conditions. To achieve this goal, we experimentally evaluated the impact of different cages, developed by scientists of the international research network COLOSS (Prevention of honey bee COlony LOSSes), on the physiology and survival of honey bees. We identified three cages that promoted good survival of honey bees. The bees from cages that exhibited greater survival had relatively lower titers of deformed wing virus, suggesting that deformed wing virus is a significant marker reflecting stress level and health status of the host. We also determined that a leak- and drip-proof feeder was an integral part of a cage system and a feeder modified from a 20-ml plastic syringe displayed the best result in providing steady food supply to bees. Finally, we also demonstrated that the addition of protein to the bees' diet could significantly increase the level ofvitellogenin gene expression and improve bees' survival. This international collaborative study represents a critical step toward improvement of cage designs and feeding regimes for honey bee laboratory experiments.

The gut microbiota plays an essential role in the health of bees. Scientific evidence suggests that diet and infection can affect the gut microbiota and modulate the health of the gut; however, the interplay between those two factors and the bee gut microbiota is not well known. In this study, we used a high-throughput sequencing method to monitor the changes of gut microbiota associated with both feeding types and Nosema ceranae infection. Our results showed that the gut microbiota composition and diversity of Asian honey bee were significantly associated with both feeding types and the N. ceranae infection. More interestingly, bees fed with beebread showed higher microbiota stability and lower mortality rates than those fed with sugar water when infected by N. ceranae. Those data suggest that beebread has the potential not only to provide better nutrition but also help to establish a more stable gut microbiota to protect bees against N. ceranae infection.

Direct assessment of the vascular lesions of model animals in vivo is important for the development of new antiatherosclerotic drugs. Nevertheless, biochemical analysis of the lipid profile in blood in vitro remains the most common way to evaluate the therapeutic effect of drugs targeting atherosclerosis because of an inherent difficulty to access the vascular wall. Using hypercholesterolemic zebrafish, we present an orchestrated application of Raman spectral measurements and confocal fluorescence imaging to interrogate the pharmacological response of atherosclerotic lesions in situ and in vivo. For demonstration, we investigated two commonly prescribed antihyperlipidemic drugs, ezetimibe and atorvastatin. The treatment of ezetimibe or atorvastatin alone decreased effectively the deposition of lipids in the vascular wall, and a combined dose showed a synergistic effect. Atorvastatin exerted a profound antioxidative effect on vascular fatty lesions. Analysis of individual lesions shows further that these lesions exhibited a heterogeneous response to the treatment of atorvastatin; a significant fraction of, but not all, the lesions became nonoxidized after the intervention. Beyond its efficacies in suppressing both the accumulation and oxidation of vascular lipids, atorvastatin expedited the clearance of vascular lipids. The possession of pleotropic (multiple) therapeutic effects on vascular fatty lesions of hypercholesterolemic zebrafish by atorvastatin is notably consistent with the known pharmaceutical effects of this drug on human beings. These results improve our understanding of the antiatherosclerotic effect of drugs. We envisage that our approach has the potential to become a platform to predict the pharmaceutical effects of new drugs aiming to cure human atherosclerotic diseases.