Transcriptional responses in Honey Bee larvae infected with chalkbrood fungus

<p>Abstract</p> <p>Background</p> <p>Diseases and other stress factors working synergistically weaken honey bee health and may play a major role in the losses of bee populations in recent years. Among a large number of bee diseases, chalkbrood has been on the rise. We present here the experimental identification of honey bee genes that are differentially expressed in response to infection of honey bee larvae with the chalkbrood fungus, <it>Ascosphaera apis</it>.</p> <p>Results</p> <p>We used cDNA-AFLP ^®Technology to profile transcripts in infected and uninfected bee larvae. From 64 primer combinations, over 7,400 transcriptionally-derived fragments were obtained A total of 98 reproducible polymorphic cDNA-AFLP fragments were excised and sequenced, followed by quantitative real-time RT-PCR (qRT-PCR) analysis of these and additional samples.</p> <p>We have identified a number of differentially-regulated transcripts that are implicated in general mechanisms of stress adaptation, including energy metabolism and protein transport. One of the most interesting differentially-regulated transcripts is for a chitinase-like enzyme that may be linked to anti-fungal activities in the honey bee larvae, similarly to gut and fat-body specific chitinases found in mosquitoes and the red flour beetle. Surprisingly, we did not find many components of the well-characterized NF-κB intracellular signaling pathways to be differentially-regulated using the cDNA-AFLP approach. Therefore, utilizing qRT-PCR, we probed some of the immune related genes to determine whether the lack of up-regulation of their transcripts in our analysis can be attributed to lack of immune activation or to limitations of the cDNA-AFLP approach.</p> <p>Conclusions</p> <p>Using a combination of cDNA-AFLP and qRT-PCR analyses, we were able to determine several key transcriptional events that constitute the overall effort in the honey bee larvae to fight natural fungal infection. Honey bee transcripts identified in this study are involved in critical functions related to transcriptional regulation, apoptotic degradation of ubiquitinated proteins, nutritional regulation, and RNA processing. We found that immune regulation of the anti-fungal responses in honey bee involves highly coordinated activation of both NF-κB signaling pathways, leading to production of anti-microbial peptides. Significantly, activation of immune responses in the infected bee larvae was associated with down-regulation of major storage proteins, leading to depletion of nutritional resources.</p

Chronic parasitization by Nosema microsporidia causes global expression changes in core nutritional, metabolic and behavioral pathways in honey bee workers (Apis mellifera)

BACKGROUND: Chronic infections can profoundly affect the physiology, behavior, fitness and longevity of individuals, and may alter the organization and demography of social groups. Nosema apis and Nosema ceranae are two microsporidian parasites which chronically infect the digestive tract of honey bees (Apis mellifera). These parasites, in addition to other stressors, have been linked to increased mortality of individual workers and colony losses in this key pollinator species. Physiologically, Nosema infection damages midgut tissue, is energetically expensive and alters expression of immune genes in worker honey bees. Infection also accelerates worker transition from nursing to foraging behavior (termed behavioral maturation). Here, using microarrays, we characterized global gene expression patterns in adult worker honey bee midgut and fat body tissue in response to Nosema infection. RESULTS: Our results indicate that N. apis infection in young workers (1 and 2 days old) disrupts midgut development. At 2 and 7 days post-infection in the fat body tissue, N. apis drives metabolic changes consistent with energetic costs of infection. A final experiment characterizing gene expression in the fat bodies of 14 day old workers parasitized with N. apis and N. ceranae demonstrated that Nosema co-infection specifically alters conserved nutritional, metabolic and hormonal pathways, including the insulin signaling pathway, which is also linked to behavioral maturation in workers. Interestingly, in all experiments, Nosema infection did not appear to significantly regulate overall expression of canonical immune response genes, but infection did alter expression of acute immune response genes identified in a previous study. Comparative analyses suggest that changes in nutritional/metabolic processes precede changes in behavioral maturation and immune processes. CONCLUSIONS: These genome-wide studies of expression patterns can help us disentangle the direct and indirect effects of chronic infection, and understand the molecular pathways that regulate disease symptoms. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1471-2164-14-799) contains supplementary material, which is available to authorized users

Métodos para la investigación de la loque americana

American foulbrood is one of the most devastating diseases of the honey bee. It is caused by the spore-forming, Gram-positive rod-shaped bacterium Paenibacillus larvae. The recent updated genome assembly and annotation for this pathogen now permits in-depth molecular studies. In this paper, selected techniques and protocols for American foulbrood research are provided, mostly in a recipe-like format that permits easy implementation in the laboratory. Topics covered include: working with Paenibacillus larvae, basic microbiological techniques, experimental infection, and “’omics” and other sophisticated techniques. Further, this chapter covers other technical information including biosafety measures to guarantee the safe handling of this pathogen.La loque americana es una de las enfermedades más devastadoras de la abeja melífera, causada por el bacilo, formador de esporas Grampositivo Paenibacillus larvae. El reciente ensamblaje y anotación del genoma de este patógeno permite actualmente la realización de profundos estudios moleculares. En este trabajo, se proporcionan técnicas y protocolos seleccionados para la investigación de la loque americana, principalmente bajo la forma de protocolos de trabajo con una estructura similar al de las recetas, para facilitar su implementación en el laboratorio. Los temas desarrollados incluyen: el trabajo con Paenibacillus larvae, técnicas básicas microbiológicas, la infección experimental, y "'ómicas" y otras técnicas sofisticadas. Además, este capítulo abarca otro tipo de información técnica, incluyendo medidas de bioseguridad para garantizar la seguridad en el manejo de este patógeno.Trabajo publicado en Dietemann, V.; Ellis, J. D.; Neumann, P. (eds.) The Coloss Beebook, Volume II: standard methods for Apis mellifera pest and pathogen research. Journal of Apicultural Research, 52(1).Facultad de Ciencias Agrarias y Forestale

Pervasiveness of Parasites in Pollinators

Many pollinator populations are declining, with large economic and ecological implications. Parasites are known to be an important factor in the some of the population declines of honey bees and bumblebees, but little is known about the parasites afflicting most other pollinators, or the extent of interspecific transmission or vectoring of parasites. Here we carry out a preliminary screening of pollinators (honey bees, five species of bumblebee, three species of wasp, four species of hoverfly and three genera of other bees) in the UK for parasites. We used molecular methods to screen for six honey bee viruses, Ascosphaera fungi, Microsporidia, and Wolbachia intracellular bacteria. We aimed simply to detect the presence of the parasites, encompassing vectoring as well as actual infections. Many pollinators of all types were positive for Ascosphaera fungi, while Microsporidia were rarer, being most frequently found in bumblebees. We also detected that most pollinators were positive for Wolbachia, most probably indicating infection with this intracellular symbiont, and raising the possibility that it may be an important factor in influencing host sex ratios or fitness in a diversity of pollinators. Importantly, we found that about a third of bumblebees (Bombus pascuorum and Bombus terrestris) and a third of wasps (Vespula vulgaris), as well as all honey bees, were positive for deformed wing virus, but that this virus was not present in other pollinators. Deformed wing virus therefore does not appear to be a general parasite of pollinators, but does interact significantly with at least three species of bumblebee and wasp. Further work is needed to establish the identity of some of the parasites, their spatiotemporal variation, and whether they are infecting the various pollinator species or being vectored. However, these results provide a first insight into the diversity, and potential exchange, of parasites in pollinator communities

美洲幼虫腐臭病研究的标准方法

American foulbrood is one of the most devastating diseases of the honey bee. It is caused by the spore-forming, Gram-positive rod-shaped bacterium Paenibacillus larvae. The recent updated genome assembly and annotation for this pathogen now permits in-depth molecular studies. In this paper, selected techniques and protocols for American foulbrood research are provided, mostly in a recipe-like format that permits easy implementation in the laboratory. Topics covered include: working with Paenibacillus larvae, basic microbiological techniques, experimental infection, and “’omics” and other sophisticated techniques. Further, this chapter covers other technical information including biosafety measures to guarantee the safe handling of this pathogen.La loque americana es una de las enfermedades más devastadoras de la abeja melífera, causada por el bacilo, formador de esporas Gram-positivo Paenibacillus larvae. El reciente ensamblaje y anotación del genoma de este patógeno permite actualmente la realización de profundos estudios moleculares. En este trabajo, se proporcionan técnicas y protocolos seleccionados para la investigación de la loque americana, principalmente bajo la forma de protocolos de trabajo con una estructura similar al de las recetas, para facilitar su implementación en el laboratorio. Los temas desarrollados incluyen: el trabajo con Paenibacillus larvae, técnicas básicas microbiológicas, la infección experimental, y "'ómicas" y otras técnicas sofisticadas. Además, este capítulo abarca otro tipo de información técnica, incluyendo medidas de bioseguridad para garantizar la seguridad en el manejo de este patógeno.美洲幼虫腐臭病是最具毁灭性的疾病之一，由革兰氏阳性杆状菌 Paenibacillus larvae 引起。近年来，随着基因组学的开展，该病原体的基因组组装和注释已成为开展，深入的分子研究成为可能。本文提供了经选择的美洲幼虫腐臭病研究技术和实验程序，大多数以“食谱”的格式给出， 很容易在实验室开展操作。覆盖的主题包括：Paenibacillus larvae 的处理技术，基本微生物技术、实验感染技术、“组学”以及其他的一些复杂技术。此外，本章还包含了生物安全的评价方法，以确保安全的开展该病原体的研究The Research Foundation of Flanders (FWO-Vlaanderen; G.0163.11)http://www.ibra.org.uk/categories/jaram201

Standard methods for American foulbrood research

American foulbrood is one of the most devastating diseases of the honey bee. It is caused by the spore-forming, Gram-positive rod-shaped bacterium Paenibacillus larvae. The recent updated genome assembly and annotation for this pathogen now permits in-depth molecular studies. In this paper, selected techniques and protocols for American foulbrood research are provided, mostly in a recipe-like format that permits easy implementation in the laboratory. Topics covered include: working with Paenibacillus larvae, basic microbiological techniques, experimental infection, and “’omics” and other sophisticated techniques. Further, this chapter covers other technical information including biosafety measures to guarantee the safe handling of this pathogen