scholarly journals Artificial Diets Modulate Infection Rates by Nosema ceranae in Bumblebees

2021 ◽  
Vol 9 (1) ◽  
pp. 158
Author(s):  
Tamara Gómez-Moracho ◽  
Tristan Durand ◽  
Cristian Pasquaretta ◽  
Philipp Heeb ◽  
Mathieu Lihoreau
Keyword(s):  
Bombus Terrestris ◽  
Parasite Prevalence ◽  
Nosema Ceranae ◽  
Success Rates ◽  
Artificial Diets ◽  
Experimental Conditions ◽  
New Approach ◽  
Low Protein ◽  
Energetic Stress ◽  
Colony Collapse

Parasites alter the physiology and behaviour of their hosts. In domestic honey bees, the microsporidia Nosema ceranae induces energetic stress that impairs the behaviour of foragers, potentially leading to colony collapse. Whether this parasite similarly affects wild pollinators is little understood because of the low success rates of experimental infection protocols. Here, we present a new approach for infecting bumblebees (Bombus terrestris) with controlled amounts of N. ceranae by briefly exposing individual bumblebees to parasite spores before feeding them with artificial diets. We validated our protocol by testing the effect of two spore dosages and two diets varying in their protein to carbohydrate ratio on the prevalence of the parasite (proportion of PCR-positive bumblebees), the intensity of parasites (spore count in the gut and the faeces), and the survival of bumblebees. Overall, insects fed a low-protein, high-carbohydrate diet showed the highest parasite prevalence (up to 70%) but lived the longest, suggesting that immunity and survival are maximised at different protein to carbohydrate ratios. Spore dosage did not affect parasite infection rate and host survival. The identification of experimental conditions for successfully infecting bumblebees with N. ceranae in the lab will facilitate future investigations of the sub-lethal effects of this parasite on the behaviour and cognition of wild pollinators.

scholarly journals Artificial diets modulate infection rates by Nosema ceranae in bumblebees

2020 ◽  
Author(s):  
Tamara Gómez-Moracho ◽  
Tristan Durand ◽  
Cristian Pasquaretta ◽  
Philipp Heeb ◽  
Mathieu Lihoreau
Keyword(s):  
Bombus Terrestris ◽  
Sucrose Solution ◽  
Parasite Prevalence ◽  
Nosema Ceranae ◽  
Success Rates ◽  
Artificial Diets ◽  
Experimental Conditions ◽  
Low Protein ◽  
Energetic Stress ◽  
Colony Collapse

AbstractParasites alter the physiology and behaviour of their hosts. In domestic honey bees, the microsporidia Nosema ceranae induces an energetic stress and impairs the behaviour of foragers, potentially leading to colony collapse. Whether this emerging parasite similarly affects wild pollinators is little understood because of the low success rates of experimental infection protocols. Here we established a new apporach for infecting bumblebees (Bombus terrestris) with controlled amounts of N. ceranae, by briefly exposing individual bumblebees to a sucrose solution containing parasite spores, before feeding them with artificial diets. We validated our protocol by testing the effect of two spore dosages and two diets varying in their protein to carbohydrate ratio, on the prevalence of the parasite (proportion of infected bees), the intensity of infection (spore count in the gut), and the survival of bumblebees. Insects fed a low-protein high-carbohydrate diet showed highest parasite prevalence (up to 70%) but lived longest, suggesting that immunity and survival of bumblebees are maximised at different protein to carbohydrate ratios. Spore dosage had no effect on parasite infection rate and host survival. The identification of experimental conditions for successfully infecting bumblebees with N. ceranae in the lab will facilitate investigations of the sub-lethal effects of this parasite on the behaviour and cognition of wild pollinators.

Impact of a New Teaching and Learning Approach in an Introductory Programming Course

2017 ◽  
Vol 55 (6) ◽  
pp. 789-819 ◽  
Author(s):  
Sohail Iqbal Malik ◽  
Jo Coldwell-Neilson
Keyword(s):  
Teaching And Learning ◽  
Positive Impact ◽  
Dropout Rates ◽  
Success Rates ◽  
Final Exam ◽  
Introductory Programming ◽  
New Approach ◽  
Course Materials ◽  
Didactic Triangle ◽  
The Impact

High failure and dropout rates are reported in introductory programming (IP) courses in different studies despite extensive research attempting to address the issue. In this study, we introduced an ADRI (Approach, Deployment, Result, Improvement) approach in the teaching and learning process of an IP course to improve learning and success rates. All three entities of the didactic triangle (student, instructor, and content) were involved in the research to better understand and execute the proposed approach. The IP course materials were redesigned based on the ADRI approach, and an editor was developed to promote the new approach and encourage students to complete the various stages required in the approach. Two surveys were conducted, and final exam grades over four semesters were compared with determine the impact of including the ADRI approach in the course. We concluded that the ADRI approach provides a positive impact on outcomes that the students achieved during the course. It engages students in practicing their programming skills and provides a new presentation style for examples and exercises which discourages students from taking programming shortcuts. It not only helps to reduce the failure and, significantly, the dropout rates from the IP course but also impacts positively on all students who passed the IP course.

scholarly journals Tuning Alginate Microparticle Size via Atomization of Non-Newtonian Fluids

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7601
Author(s):  
Beatriz Arauzo ◽  
Álvaro González-Garcinuño ◽  
Antonio Tabernero ◽  
María Pilar Lobera ◽  
Jesús Santamaría ◽  
...  
Keyword(s):  
Particle Size ◽  
Numerical Study ◽  
Pressure Ratio ◽  
Barium Chloride ◽  
Newtonian Fluids ◽  
Dimensionless Numbers ◽  
Experimental Conditions ◽  
New Approach ◽  
Hydrogel Beads ◽  
Key Factor

A new approach based on the atomization of non-Newtonian fluids has been proposed to produce microparticles for a potential inhalation route. In particular, different solutions of alginate were atomized on baths of different crosslinkers, piperazine and barium chloride, obtaining microparticles around 5 and 40 microns, respectively. These results were explained as a consequence of the different viscoelastic properties, since oscillatory analysis indicated that the formed hydrogel beads with barium chloride had a higher storage modulus (1000 Pa) than the piperazine ones (20 Pa). Pressure ratio (polymer solution-air) was identified as a key factor, and it should be from 0.85 to 1.00 to ensure a successful atomization, obtaining the smallest particle size at intermediate pressures. Finally, a numerical study based on dimensionless numbers was performed to predict particle size depending on the conditions. These results highlight that it is possible to control the microparticles size by modifying either the viscoelasticity of the hydrogel or the experimental conditions of atomization. Some experimental conditions (using piperazine) reduce the particle size up to 5 microns and therefore allow their use by aerosol inhalation.

scholarly journals A New Approach to Producing High Yields of Pulcherrimin from Metschnikowia Yeasts

Fermentation ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 114
Author(s):  
Ewelina Pawlikowska ◽  
Beata Kolesińska ◽  
Maria Nowacka ◽  
Dorota Kregiel
Keyword(s):  
Culture Media ◽  
Growth Control ◽  
Tween 80 ◽  
Resonance Spectroscopy ◽  
Experimental Conditions ◽  
Biofilm Inhibition ◽  
Iron Chelate ◽  
New Approach ◽  
1H Nuclear Magnetic Resonance ◽  
High Yields

Pulcherrimin, a red iron chelate, is produced by some yeasts and bacteria. It plays important ecological roles in many ecosystems, including growth control, biofilm inhibition and photoprotection. In this study, fifteen yeast strains of the genus Metschnikowia were characterized based on their production of pulcherrimin. Yeast pulcherrimin was isolated and its purity assessed using 1H nuclear magnetic resonance spectroscopy. Under experimental conditions, pulcherrimin formation varied depending on both the tested strains and culture media. The best producers formed up to 240 mg/L of pulcherrimin in minimal medium with glucose as the carbon source, supplemented with 0.05% FeCl3 and 0.1% Tween 80. This study presents a new approach to producing high yields of pulcherrimin from yeasts.

scholarly journals Dominance of Nosema ceranae in honey bees in the Balkan countries in the absence of symptoms of colony collapse disorder

Apidologie ◽  
2011 ◽  
Vol 42 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Jevrosima Stevanovic ◽  
Zoran Stanimirovic ◽  
Elke Genersch ◽  
Sanja R. Kovacevic ◽  
Jovan Ljubenkovic ◽  
...  
Keyword(s):  
Honey Bees ◽  
Nosema Ceranae ◽  
Colony Collapse Disorder ◽  
Balkan Countries ◽  
Colony Collapse

scholarly journals Rapid Gastrointestinal Passage May Protect Bombus terrestris from Becoming a True Host for Nosema ceranae

2020 ◽  
Vol 86 (12) ◽  
Author(s):  
Sebastian Gisder ◽  
Lennart Horchler ◽  
Franziska Pieper ◽  
Vivian Schüler ◽  
Peter Šima ◽  
...  
Keyword(s):  
Health Status ◽  
Honey Bees ◽  
Bombus Terrestris ◽  
Infectious Agent ◽  
Nosema Ceranae ◽  
New Host ◽  
Content Type ◽  
Field Samples ◽  
True Infection

ABSTRACT Pollination provided by managed honey bees as well as by all the wild bee species is a crucial ecosystem service contributing to the conservation of biodiversity and human food security. Therefore, it is not only the health status of honey bees but also the health status of wild bees that concerns us all. In this context, recent field studies suggesting interspecies transmission of the microsporidium parasite Nosema ceranae from honey bees (Apis mellifera) to bumblebees (Bombus spp.) were alarming. On the basis of these studies, N. ceranae was identified as an emerging infectious agent (EIA) of bumblebees, although knowledge of its impact on its new host was still elusive. In order to investigate the infectivity, virulence, and pathogenesis of N. ceranae infections in bumblebees, we performed controlled laboratory exposure bioassays with Bombus terrestris by orally inoculating the bees with infectious N. ceranae spores. We comprehensively analyzed the infection status of the bees via microscopic analysis of squash preparations, PCR-based detection of N. ceranae DNA, histology of Giemsa-stained tissue sections, and species-specific fluorescence in situ hybridization. We did not find any evidence for a true infection of bumblebees by N. ceranae. Through a series of experiments, we ruled out the possibility that spore infectivity, spore dosage, incubation time, or age and source of the bumblebees caused these negative results. Instead, our results clearly demonstrate that no infection and production of new spores took place in bumblebees after they ingested N. ceranae spores in our experiments. Thus, our results question the classification of N. ceranae as an emerging infectious agent for bumblebees. IMPORTANCE Emerging infectious diseases (EIDs) pose a major health threat to both humans and animals. EIDs include, for instance, those that have spread into hitherto naive populations. Recently, the honey bee-specific microsporidium Nosema ceranae has been detected by molecular methods in field samples of bumblebees. This detection of N. ceranae DNA in bumblebees led to the assumption that N. ceranae infections represent an EID of bumblebees and resulted in speculations on the role of this pathogen in driving bumblebee declines. In order to address the issue of whether N. ceranae is an emerging infectious agent for bumblebees, we experimentally analyzed host susceptibility and pathogen reproduction in this new host-pathogen interaction. Surprisingly, we did not find any evidence for a true infection of Bombus terrestris by N. ceranae, questioning the classification of N. ceranae infections as EIDs of bumblebees and demonstrating that detection of microsporidian DNA does not equal detection of microsporidian infection.

Single-clone and mixed-clone infections versus host environment in Crithidia bombi infecting bumblebees

Parasitology ◽  
1998 ◽  
Vol 117 (4) ◽  
pp. 331-336 ◽  
Author(s):  
B. IMHOOF ◽  
P. SCHMID-HEMPEL
Keyword(s):  
Bombus Terrestris ◽  
Infection Intensity ◽  
Parasite Prevalence ◽  
Mixed Genotype ◽  
Host Environment ◽  
Crithidia Bombi ◽  
The Family ◽  
Single Clone ◽  
Parasite Evolution ◽  
Host Heterogeneity

Current theories assume that adaptive parasite evolution explains variation in the level of virulence and parasite success. In particular, mixed-genotype infections by parasites should generally be more virulent, and faster multiplying strains more successful, either because fixed strategies have evolved or because parasites facultatively alter virulence in response to co-infecting competitors. We compared several measures of parasite success and virulence between single-clone and mixed-clone infections of 2 strains of the trypanosome Crithidia bombi in its bumblebee host, Bombus terrestris. Contrary to expectation, we could not find differences between single-clone and mixed-clone infections in parasite prevalence, infection success, duration and clearance rate. However, a clearly significant effect of colony on infection intensity was present, and the colony effect emerged in virtually all other measures. We thus conclude that host environment as defined by the family (colony) genotype and thus host heterogeneity are more important in determining parasite virulence than the parasite characteristics. This does not invalidate modern theories of parasite evolution but suggests that variation in both hosts and parasites must be taken into account in more detail.

scholarly journals Colistin Is Extensively Lost during Standard In Vitro Experimental Conditions

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Matti Karvanen ◽  
Christer Malmberg ◽  
Pernilla Lagerbäck ◽  
Lena E. Friberg ◽  
Otto Cars
Keyword(s):  
Protein Binding ◽  
Time Course ◽  
Equilibrium Constants ◽  
Soda Lime Glass ◽  
Adsorption Model ◽  
Limit Of Quantification ◽  
Experimental Conditions ◽  
Low Protein ◽  
Time Kill

ABSTRACT Colistin adheres to a range of materials, including plastics in labware. The loss caused by adhesion influences an array of methods detrimentally, including MIC assays and in vitro time-kill experiments. The aim of this study was to characterize the extent and time course of colistin loss in different types of laboratory materials during a simulated time-kill experiment without bacteria or plasma proteins present. Three types of commonly used large test tubes, i.e., soda-lime glass, polypropylene, and polystyrene, were studied, as well as two different polystyrene microplates and low-protein-binding microtubes. The tested concentration range was 0.125 to 8 mg/liter colistin base. Exponential one-phase and two-phase functions were fitted to the data, and the adsorption of colistin to the materials was modeled with the Langmuir adsorption model. In the large test tubes, the measured start concentrations ranged between 44 and 102% of the expected values, and after 24 h, the concentrations ranged between 8 and 90%. The half-lives of colistin loss were 0.9 to 12 h. The maximum binding capacities of the three materials ranged between 0.4 and 1.1 μg/cm2, and the equilibrium constants ranged between 0.10 and 0.54 ml/μg. The low-protein-binding microtubes showed start concentrations between 63 and 99% and concentrations at 24 h of between 59 and 90%. In one of the microplates, the start concentrations were below the lower limit of quantification at worst. In conclusion, to minimize the effect of colistin loss due to adsorption, our study indicates that low-protein-binding polypropylene should be used when possible for measuring colistin concentrations in experimental settings, and the results discourage the use of polystyrene. Furthermore, when diluting colistin in protein-free media, the number of dilution steps should be minimized.

Comparison of the energetic stress associated with experimental Nosema ceranae and Nosema apis infection of honeybees (Apis mellifera)

2011 ◽  
Vol 109 (3) ◽  
pp. 605-612 ◽  
Author(s):  
Raquel Martín-Hernández ◽  
Cristina Botías ◽  
Laura Barrios ◽  
Amparo Martínez-Salvador ◽  
Aránzazu Meana ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Nosema Ceranae ◽  
Nosema Apis ◽  
Energetic Stress
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