nosema ceranae
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2022 ◽  
Author(s):  
Fan Yuanchan ◽  
Dafu Chen ◽  
Rui Guo

Apis cerana is the original host for Nosema ceranae, a widespread fungal parasite resulting in bee nosemosis, which leads to severe losses for apiculture industry throughout the world. However, knowledge of N. ceranae infecting eastern honeybees is extremely limited. Currently, the mechanism underlying N. ceranae infection is still largely unknown. Based on our previously gained high-quality transcriptome datasets, comparative transcriptomic investigation was conducted in this work, with a focus on virulence factor-associated differentially expressed genes (DEGs). Microscopic observation showed that A. c. cerana workers midguts were effectively infected after inoculation with clean spores of N. ceranae. Totally, 1411, 604, and 38 DEGs were identified from NcCK vs. NcT1, NcCK vs. NcT2 and NcT1 vs. NcT2 comparison groups. Venn analysis showed that ten up-regulated genes and nine down-regulated ones were shared by aforementioned comparison groups. GO category indicated these DEGs were involved in a series of functional terms relevant to biological process, cellular component, and molecular function, such as metabolic process, cell part, and catalytic activity. Additionally, KEGG pathway analysis suggested that the DEGs were engaged in an array of pathways of great importance, such as metabolic pathway, glycolysis, and biosynthesis of secondary metabolites. Further, expression clustering analysis demonstrated that majority of genes encoding virulence factors such as ricin B lectins and polar tube proteins displayed apparent up-regulation, whereas a few virulence factor-associated genes such as hexokinase gene and 6-phosphofructokinase gene presented down-regulation during the fungal infection. Finally, the expression trend of 14 DEGs was confirmed by RT-qPCR, validating the reliability of our transcriptome datasets. These results together demonstrated that an overall alteration of the transcriptome of N. ceranae occurred during the infection of A. c. ceranae workers, and most of virulence factor-related genes were induced to activation to promote the fungal invasion. Our findings not only lay a foundation for clarifying the molecular mechanism underlying N. ceranae infection of eastern honeybee workers, but also shed light on developing novel targets for microsporidiosis control.


2022 ◽  
Vol 12 (2) ◽  
pp. 783
Author(s):  
Giovanni Formato ◽  
Jorge Rivera-Gomis ◽  
Jernej Bubnic ◽  
Raquel Martín-Hernández ◽  
Marcella Milito ◽  
...  

Nosemosis is a serious microsporidian disease of adult European honey bees caused by the spore-forming unicellular fungi Nosema apis and Nosema ceranae. In this paper we describe the currently known techniques for nosemosis prevention and control including Good Beekeeping Practices (GBPs) and biosecurity measures (BMBs). Topics such as queen renewal, nosema-resistant bees and hygienic and control methods are described. Strong efforts are currently provided to find more a sustainable solution than the use of antibiotics. So far, it seems that the best way to approach nosemosis is given by an “integrated pest management strategy”, which foresees the contemporary application of different, specific GBPs and BMBs.


2022 ◽  
Author(s):  
Qi Long ◽  
Minghui Sun ◽  
Xiaoxue Fan ◽  
Wende Zhang ◽  
Dingding Zhou ◽  
...  

Nosema ceranae is an intracellular fungal parasite for honeybees, leading to chronic disease named bee nosemosis with worldwide distribution. Asian honeybee (Apis cerana) is the original host for N. ceranae, but the impact of N. ceranae infection on A. cerana physiology is largely unknown. In this current work, workers of Apis cerana cerana, a subspecies of Asian honeybee, were artificially inoculated with N. ceranae spores and reared under lab conditions, followed by detection of fungal spore load as well as host sucrose solution consumption, midgut epithelial cell structure, and lifespan. The result of spore counting suggested that the spore load in the host midgut decreased significantly during 1 dpi-2 dpi, whereas that displayed an elevated trend among 2 dpi-13 dpi. The sucrose solution consumption of workers in N. ceranae-inoculated groups among 1 dpi-20 dpi was always higher than that of workers in un-inoculated groups; additionally, the difference of sucrose solution consumption between these two groups at 4 dpi, 5 dpi, and 13 dpi was of significance. Based on microscopic observation of paraffin sections, darkly stained parasites were clearly detected in the midgut epithelial cells of N. ceranae-inoculated workers at 7 dpi-10 dpi, whereas no parasite was observed in those of un-inoculated workers. In addition, the boundaries of un-inoculated host epithelial cells were intact and the darkly stained nucleus were clear, while the boundaries of midgut epithelial cells of N. ceranae-inoculated workers were blurred, the nucleus were almost disappeared, and the nucleic acid substances were diffused. Moreover, the survival rates of workers in both N. ceranae-inoculated groups and un-inoculated groups at 1 dpi-5 dpi were pretty high and then started to decrease at 5 dpi; the survival rate of workers in N. ceranae-inoculated groups was always lower than that in un-inoculated groups, with significant difference between these two groups during 11 dpi-20 dpi. These results together indicate that the quantity of fungal spores continuously elevated with the microsporidian multiplication, causing energetic stress for workers and host cell structure damage, which further negatively affected the host lifespan. Our findings offer a solid basis not only for exploring the molecular mechanism underlying N. ceranae infection but also for investigating the interaction between N. ceranae and eastern honeybee.


Author(s):  
Jozef J. M. van der Steen ◽  
Marc J. A. Hendriks ◽  
Anne D. van Diepeningen ◽  
Marga P. E. van Gent-Pelzer ◽  
Theo A. J. van der Lee
Keyword(s):  

2022 ◽  
Vol 12 (1) ◽  
pp. 422
Author(s):  
Giovanni Cilia ◽  
Giacomo Luchetti ◽  
Antonio Nanetti

The microsporidian Nosema ceranae is a severe threat to the western honey bee Apis mellifera, as it is responsible for nosemosis type C, which leads the colonies to dwindle and collapse. Infection quantification is essential to clinical and research aims. Assessment is made often with molecular assays based on rRNA genes, which are present in the N. ceranae genome as multiple and polymorphic copies. This study aims to compare two different methods of Real-Time PCR (qPCR), respectively relying on the 16S rRNA and Hsp70 genes, the first of which is described as a multiple and polymorphic gene. Young worker bees, hatched in the laboratory and artificially inoculated with N. ceranae spores, were incubated at 33 °C and subject to different treatment regimens. Samples were taken post-infection and analyzed with both qPCR methods. Compared to Hsp70, the 16S rRNA method systematically detected higher abundance. Straightforward conversion between the two methods is made impossible by erratic 16s rRNA/Hsp70 ratios. The 16s rRNA polymorphism showed an increase around the inoculated dose, where a higher prevalence of ungerminated spores was expected due to the treatment effects. The possible genetic background of that irregular distribution is discussed in detail. The polymorphic nature of 16S rRNA showed to be a limit in the infection quantification. More reliably, the N. ceranae abundance can be assessed in honey bee samples with methods based on the single-copy gene Hsp70.


2021 ◽  
Vol 9 (1) ◽  
pp. 10
Author(s):  
Delka Salkova ◽  
Rositsa Shumkova ◽  
Ralitsa Balkanska ◽  
Nadezhda Palova ◽  
Boyko Neov ◽  
...  

Environmental DNA (eDNA) analysis is related to screening genetic material of various organisms in environmental samples. Honey represents a natural source of exogenous DNA, which allows for the detection of different honey bee pathogens and parasites. In the present study, we extracted DNA from 20 honey samples from different regions in Bulgaria and tested for the presence of DNA of the ectoparasitic mite Varroa destructor, as well as Nosema apis and Nosema ceranae. Only Nosema ceranae was detected, showing up in 30% of all samples, which confirms the widespread prevalence of this pathogen. All positive samples were found in plain regions of the country, while this pathogen was not detected in mountainous parts. None of the samples gave positive amplifications for the Nosema apis and Varroa mite. The obtained results from this study confirm previous observations that eDNA contained in honey is a potent source for effective biomonitoring of actual diseases in the honey bee.


2021 ◽  
Author(s):  
Jun Ke Yu ◽  
Da Fu Chen ◽  
Rui Guo

Apis cerana cerana is an excellent subspecies of Apis cerana, playing a vital role in pollination for wild flowers and crops as well as ecological balance. Nosema ceranae, an emergent fungal parasite infecting various bee species, originates from eastern honeybee. In this article, midguts of N. ceranae-inoculated A. c. cerana workers at 7 days post inoculation (dpi) and 10 dpi (AcT1 and AcT2) and un-inoculated workers' midguts (AcCK1, AcCK2) were subjected to Nanopore-based genome-wide DNA methylation sequencing. Totally, 1773258, 2151476, 1927874 and 2109961 clean reads were generated from AcCK1, AcCK2, AcT1, and AcT2 groups, with the N50 lengths of 7548, 7936, 7678, and 7291 and the average quality value of 8.97, 8.95, 9.24, and 8.98, respectively. Among these, 93.85%, 94.49%, 88.69%, and 81.27% clean reads could be mapped to the reference genome of A. c. cerana. In the aforementioned four groups, 2149685, 2614513, 1637018 and 2726985 CHG sites were identified; the numbers of CHH sites were 9581990, 11801082, 7178559, and 12342423, whereas those of CpG sites were 14325356, 15703508, 14856284 and 13956849, respectively. Additionally, there were 36114, 118867, 30249, and 82984 6mA methylation sites respectively discovered. These data can be used for identifying differential 5mC methylation and 6mA methylation engaged in response of eastern honeybee workers to N. ceranae infestation, and for investigating the 5mC or 6mA methylation-mediated mechanism underlying host response.


Biomolecules ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1657
Author(s):  
Luisa Ugolini ◽  
Giovanni Cilia ◽  
Eleonora Pagnotta ◽  
Lorena Malaguti ◽  
Vittorio Capano ◽  
...  

The microsporidian fungus Nosema ceranae represents one of the primary bee infection threats worldwide and the antibiotic fumagillin is the only registered product for nosemosis disease control, while few alternatives are, at present, available. Natural bioactive compounds deriving from the glucosinolate–myrosinase system (GSL–MYR) in Brassicaceae plants, mainly isothiocyanates (ITCs), are known for their antimicrobial activity against numerous pathogens and for their health-protective effects in humans. This work explored the use of Brassica nigra and Eruca sativa defatted seed meal (DSM) GSL-containing diets against natural Nosema infection in Apis mellifera colonies. DSM patties from each plant species were obtained by adding DSMs to sugar candy at the concentration of 4% (w/w). The feeding was administered in May to mildly N. ceranae-infected honey bee colonies for four weeks at the dose of 250 g/week. In the treated groups, no significant effects on colony development and bee mortality were observed compared to the negative controls. The N. ceranae abundance showed a slight but significant decrease. Furthermore, the GSL metabolism in bees was investigated, and MYR hydrolytic activity was qualitatively searched in isolated bee midgut and hindgut. Interestingly, MYR activity was detected both in the bees fed DSMs and in the control group where the bees did not receive DSMs. In parallel, ITCs were found in gut tissues from the bees treated with DSMs, corroborating the presence of a MYR-like enzyme capable of hydrolyzing ingested GSLs. On the other hand, GSLs and other GSL hydrolysis products other than ITCs, such as nitriles, were found in honey produced by the treated bees, potentially increasing the health value of the final product for human consumption. The results are indicative of a specific effect on the N. ceranae infection in managed honey bee colonies depending on the GSL activation within the target organ.


Parasitology ◽  
2021 ◽  
pp. 1-34
Author(s):  
Courtney I. MacInnis ◽  
B. Andrew Keddie ◽  
Stephen F. Pernal

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