Nosema spp. infections cause no energetic stress in tolerant honeybees

Host-pathogen coevolution leads to reciprocal adaptations, allowing pathogens to increase host exploitation or hosts to minimise costs of infection. As pathogen resistance is often associated with considerable costs, tolerance may be an evolutionary alternative. Here, we examined the effect of two closely related and highly host dependent intracellular gut pathogens, Nosema apis and Nosema ceranae, on the energetic state in Nosema tolerant and sensitive honeybees facing the infection. We quantified the three major haemolymph carbohydrates fructose, glucose, and trehalose using high-performance liquid chromatography (HPLC) as a measure for host energetic state. Trehalose levels in the haemolymph were negatively associated with N. apis infection intensity and with N. ceranae infection regardless of the infection intensity in sensitive honeybees. Nevertheless, there was no such association in Nosema spp. infected tolerant honeybees. These findings suggest that energy availability in tolerant honeybees was not compromised by the infection. This result obtained at the individual level may also have implications at the colony level where workers in spite of a Nosema infection can still perform as well as healthy bees, maintaining colony efficiency and productivity.The Deutsche Forschungsgemeinschaft DFG priority programme SPP 1399 ―Host-parasite co-evolution‖ (grant number MO373/26- 2).http://link.springer.com/journal/4362017-06-30hb2016Zoology and Entomolog

Characterization of Chromosomal Instability in Murine Colitis-Associated Colorectal Cancer

Patients suffering from ulcerative colitis (UC) bear an increased risk for colorectal cancer. Due to the sparsity of colitis-associated cancer (CAC) and the long duration between UC initiation and overt carcinoma, elucidating mechanisms of inflammation-associated carcinogenesis in the gut is particularly challenging. Adequate murine models are thus highly desirable. For human CACs a high frequency of chromosomal instability (CIN) reflected by aneuploidy could be shown, exceeding that of sporadic carcinomas. The aim of this study was to analyze mouse models of CAC with regard to CIN. Additionally, protein expression of p53, beta-catenin and Ki67 was measured to further characterize murine tumor development in comparison to UC-associated carcinogenesis in men.The AOM/DSS model (n = 23) and IL-10(-/-) mice (n = 8) were applied to monitor malignancy development via endoscopy and to analyze premalignant and malignant stages of CACs. CIN was assessed using DNA-image cytometry. Protein expression of p53, beta-catenin and Ki67 was evaluated by immunohistochemistry. The degree of inflammation was analyzed by histology and paralleled to local interferon-γ release.CIN was detected in 81.25% of all murine CACs induced by AOM/DSS, while all carcinomas that arose in IL-10(-/-) mice were chromosomally stable. Beta-catenin expression was strongly membranous in IL-10(-/-) mice, while 87.50% of AOM/DSS-induced tumors showed cytoplasmatic and/or nuclear translocation of beta-catenin. p53 expression was high in both models and Ki67 staining revealed higher proliferation of IL-10(-/-)-induced CACs.AOM/DSS-colitis, but not IL-10(-/-) mice, could provide a powerful murine model to mechanistically investigate CIN in colitis-associated carcinogenesis

Parasite resistance and tolerance in honeybees at the individual and social level

Organisms living in large groups, such as social insects, are particularly vulnerable to parasite transmission. However, they have evolved diverse defence mechanisms which are not only restricted to the individual’s immune response, but also include social defences. Here, we review cases of adaptations at the individual and social level in the honeybee Apis mellifera against the ectoparasitic mite Varroa destructor and the endoparasitic microsporidians Nosema ceranae and Nosema apis. They are considered important threats to honeybee health worldwide. We highlight how individual resistance may result in tolerance at the colony level and vice versa.The Deutsche Forschungsgemeinschaft (DFG;Priority Programme SPP 1399; grant number MO373/26-2).http://www. els evier.com/locate/zoolhb2016Zoology and Entomolog

"Up" or "down" that makes the difference. How giant honeybees (Apis dorsata) see the world.

A. dorsata builds its large exposed comb high in trees or under ledges of high rocks. The "open" nest of A. dorsata, shielded (only!) by multiple layers of bees, is highly vulnerable to any kind of direct contact or close range attacks from predators. Therefore, guard bees of the outer layer of A. dorsata's nest monitor the vicinity for possible hazards and an effective risk assessment is required. Guard bees, however, are frequently exposed to different objects like leaves, twigs and other tree litter passing the nest from above and falling to the ground. Thus, downward movement of objects past the nest might be used by A. dorsata to classify these visual stimuli near the nest as "harmless". To test the effect of movement direction on defensive responses, we used circular black discs that were moved down or up in front of colonies and recorded the number of guard bees flying towards the disc. The size of the disc (diameter from 8 cm to 50 cm) had an effect on the number of guard bees responding, the bigger the plate the more bees started from the nest. The direction of a disc's movement had a dramatic effect on the attraction. We found a significantly higher number of attacks, when discs were moved upwards compared to downward movements (GLMM (estimate ± s.e.) 1.872 ± 0.149, P < 0.001). Our results demonstrate for the first time that the vertical direction of movement of an object can be important for releasing defensive behaviour. Upward movement of dark objects near the colony might be an innate releaser of attack flights. At the same time, downward movement is perceived as a "harmless" stimulus

Evaluation of direct and indirect transmission of fungal spores in ants

Parasite transmission plays a central role in disease dynamics, but little is known about the extent to which direct and indirect transmission contributes to disease dynamics in group-living animals. Quantifying transmission by contact or exposure is challenging, as direct measurements of pathogen transmission are often impractical and individual behaviour is largely unknown. Here, we attempt to tackle these twin problems through the use of a generalist entomopathogenic fungus Metarhizium robertsii to study direct and indirect transmission in the black carpenter ant Camponotus pennsylvanicus. We provide evidence that large quantities of fungal conidia (spores) can be acquired over time on the ant's cuticle and significant amounts are shed into the environment, allowing indirect transmission. Unexposed ants in the nest can be infected either through direct (i.e. social contacts) or indirect (i.e. acquisition from the environment) transmission, potentially leading to the same mortality as if all individuals of a nest would have been directly exposed to the pathogen. Our findings highlight the importance of indirect transmission routes in a species of social living organisms

Promoting factors and barriers to participation in working life for people with spinal cord injury

Background!#!It is still difficult for people with physical impairments to be and remain equally integrated into the labour market. For this reason, the question of occupational activity has explicitly been examined by the German Spinal Cord Injury Survey (GerSCI) in order to identify barriers and facilitators for labour market participation.!##!Methods!#!Cross-sectional explorative observational study. The GerSCI survey is the German part of the International Spinal Cord Injury Survey (InSCI). Using survey data from persons recruited at eight specialised SCI-centres in Germany.!##!Participants!#!1.479 persons with Spinal Cord Injury (SCI) aged 18 years and older.!##!Results!#!In a self-disclosure questionnaire, persons with SCI show themselves as a professionally well-educated and highly motivated group with most of them aiming at gainful employment and considering themselves fit for work. Many changeable and non-changeable factors have been found, which showed a high correlation with the return to work after acquired SCI.!##!Conclusion!#!Education and pain belong to the most critical factors and thereby possible approaches to increase the level of employment, which is essential and highly relevant not only for earning money but also for self-confidence and social integration. SCI has many dimensions in itself; support also should be multidimensional. Study results might help to improve participation

Number of attacking bees in response to up and downwards movement in three different disc sizes (8 cm, 25 cm, 50 cm).

<p>Discs were displayed in a 1.5 m distance to the nests. Box plots in white with red scatter plot overlay represent number of attacking bees during downward movement of discs. Box plots in grey with cyan scatter plot overlay represent number of attacking bees during upward movement of discs respectively. The total number of observations were 15 for 8 cm (colony 1 only), 34 for 25 cm (colonies 1 and 3) and 70 for 50 cm (colonies 1, 2, 4 and 5) disc sizes respectively.</p

“Up” or “down” that makes the difference. How giant honeybees (<i>Apis dorsata</i>) see the world

<div><p><i>A</i>. <i>dorsata</i> builds its large exposed comb high in trees or under ledges of high rocks. The “open” nest of <i>A</i>. <i>dorsata</i>, shielded (only!) by multiple layers of bees, is highly vulnerable to any kind of direct contact or close range attacks from predators. Therefore, guard bees of the outer layer of <i>A</i>. <i>dorsata’s</i> nest monitor the vicinity for possible hazards and an effective risk assessment is required. Guard bees, however, are frequently exposed to different objects like leaves, twigs and other tree litter passing the nest from above and falling to the ground. Thus, downward movement of objects past the nest might be used by <i>A</i>. <i>dorsata</i> to classify these visual stimuli near the nest as “harmless”. To test the effect of movement direction on defensive responses, we used circular black discs that were moved down or up in front of colonies and recorded the number of guard bees flying towards the disc. The size of the disc (diameter from 8 cm to 50 cm) had an effect on the number of guard bees responding, the bigger the plate the more bees started from the nest. The direction of a disc’s movement had a dramatic effect on the attraction. We found a significantly higher number of attacks, when discs were moved upwards compared to downward movements (GLMM (estimate ± s.e.) 1.872 ± 0.149, P < 0.001). Our results demonstrate for the first time that the vertical direction of movement of an object can be important for releasing defensive behaviour. Upward movement of dark objects near the colony might be an innate releaser of attack flights. At the same time, downward movement is perceived as a “harmless” stimulus.</p></div