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Journal of Fungi (Basel, Switzerland) Aug 2021Nosematosis is currently a frequently discussed honey bee disease caused by two types of Microsporidia: and . Nosematosis as an intestinal disease caused by these... (Review)
Review
Nosematosis is currently a frequently discussed honey bee disease caused by two types of Microsporidia: and . Nosematosis as an intestinal disease caused by these species is one of the main factors associated with the weakening and loss of hives, with none of the stressors acting in isolation and all having an important synergistic or additive effect on the occurrence of parasitic infection. The most important factors are exposure to pesticides and nutritional stress, both worsening the immune response. Honey bees become more susceptible to parasites and subsequently the disease manifests itself. Choosing the right laboratory diagnostics is important to determine the prevalence of both species. Our review summarizes the most commonly used methodologies, especially polymerase chain reaction (PCR), which is a reliable method for detecting nosematosis, as well as for distinguishing between the two species causing the disease.
PubMed: 34575752
DOI: 10.3390/jof7090714 -
Archives of Razi Institute Aug 2022Pebrine disease is the most important and dangerous disease of silkworm caused by as an obligate intracellular parasitic fungus. It has caused tremendous economic...
Pebrine disease is the most important and dangerous disease of silkworm caused by as an obligate intracellular parasitic fungus. It has caused tremendous economic losses in the silk industry in recent years. Given the fact that light microscopy method (with low accuracy) is the only method for diagnosing pebrine disease in the country, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods were adopted in this study for accurate morphological identification of the spores causing pebrine disease. Infected larvae and mother moth samples were collected from several farms (Parand, Parnian, Shaft, and Iran Silk Research Center in Gilan province, Iran). The spores were then purified using the sucrose gradient method. From each region, 20 and 10 samples were prepared for SEM and TEM analysis, respectively. In addition, an experiment was performed to evaluate the symptoms of pebrine disease by treating fourth instars with the spores purified for the present study, along with a control group. The results of SEM analysis showed that the mean±SD length and width of spores were 1.99±0.25 to 2.81±0.32 μm, respectively. Based on the obtained results, the size of spores was smaller than the () as the classic species that cause pebrine disease. In addition, transmission electron microscopy (TEM) pictures showed that the grooves of the adult spores were deeper than those of other species, Vairomorpha, and Pleistophora, and resembled in other studies. Examination of pathogenicity of the studied spores indicated that the disease symptoms in controlled conditions were similar to those in the sampled farms. The most important symptom in fourth and fifth instrars were the small size and no growth in the treatment group compared with the control group. Findings of SEM and TEM analysis showed better morphological and structural details of parasite compared with light microscopy, and demonstrated that the studied species were a native strain of specific to Iran, whose size and other characteristics were unique and introduced for the first time in this study.
Topics: Animals; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nosema
PubMed: 36883157
DOI: 10.22092/ARI.2022.356482.1853 -
Philosophical Transactions of the Royal... Jun 2022Social corbiculate bees are major pollinators. They have characteristic bacterial microbiomes associated with their hives and their guts. In honeybees and bumblebees,... (Review)
Review
Social corbiculate bees are major pollinators. They have characteristic bacterial microbiomes associated with their hives and their guts. In honeybees and bumblebees, worker guts contain a microbiome composed of distinctive bacterial taxa shown to benefit hosts. These benefits include stimulating immune and metabolic pathways, digesting or detoxifying food, and defending against pathogens and parasites. Stressors including toxins and poor nutrition disrupt the microbiome and increase susceptibility to opportunistic pathogens. Administering probiotic bacterial strains may improve the health of individual bees and of hives, and several commercial probiotics are available for bees. However, evidence for probiotic benefits is lacking or mixed. Most bacterial species used in commercial probiotics are not native to bee guts. We present new experimental results showing that cultured strains of native bee gut bacteria colonize robustly while bacteria in a commercial probiotic do not establish in bee guts. A defined community of native bee gut bacteria resembles unperturbed native gut communities in its activation of genes for immunity and metabolism in worker bees. Although many questions remain unanswered, the development of natural probiotics for honeybees, or for commercially managed bumblebees, is a promising direction for protecting the health of managed bee colonies. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
Topics: Animals; Bacteria; Bees; Gastrointestinal Microbiome; Microbiota; Probiotics; Urticaria
PubMed: 35491599
DOI: 10.1098/rstb.2021.0156 -
Trends in Parasitology Oct 2017Microsporidia may cause emerging infectious diseases (EIDs) in bumblebees. Two drivers - commercial bumblebees and managed honey bees - have been identified as possible... (Review)
Review
Microsporidia may cause emerging infectious diseases (EIDs) in bumblebees. Two drivers - commercial bumblebees and managed honey bees - have been identified as possible sources of pathogen spillover. In addition, declines in bumblebee populations may have led to lower genetic diversity and subsequent higher susceptibility to infection, enabling microsporidia to increase in prevalence. There is strong evidence for relatively recent increases in the prevalence of Nosema bombi in North America. However, the lack of definitive data on spillover by microsporidia, in North America or elsewhere, makes it difficult to identify the causes of such increases. Phylogenomic studies are urgently needed to identify the global population structure of microsporidia in bumblebees, and thus identify the source of current and future epidemics.
Topics: Animals; Bees; Genetic Variation; North America; Nosema; Phylogeny
PubMed: 28663099
DOI: 10.1016/j.pt.2017.06.001 -
Insects Oct 2021The study aims to prove the possibility of colonization of and to the intestine of the greater wax moth, detect the differences of greater wax moth based on the...
The study aims to prove the possibility of colonization of and to the intestine of the greater wax moth, detect the differences of greater wax moth based on the presence of species and examine the effect of species on the phenoloxidase level of greater wax moth compared with honeybees. Each group was fed on the 1st day of the experiment with its appropriate diet containing 10 spores per insect. Each group was checked daily, and dead insects were counted. Furthermore, changes in the level of expression of the phenoloxidase-related gene after spp. treatment on the 6th, 9th and 12th days, which was detected by Q-PCR, and the mRNA level of phenoloxidase gene were measured in all experiment groups with the CFX Connect Real-Time PCR Detection System. This study shows that L. has a 66.7% mortality rate in mixed infections, a 50% mortality rate in infection, a 40% mortality rate in infection, while there is no death in . A significant difference was found in the mixed infection group compared to the single infection groups by means of and (Duncan, < 0.05). histopathology also shows that spores multiply in the epithelial cells of greater wax moth without causing any death. The increase in the mRNA level of Phenoloxidase gene in was detected (Kruskal-Wallis, < 0.05), while the mRNA level of the Phenoloxidase gene did not change in (Kruskal-Wallis, > 0.05). These findings prove that the species can colonize into the greater wax moth, which contributes to the dissemination of these species between beehives.
PubMed: 34680722
DOI: 10.3390/insects12100953 -
Italian Journal of Food Safety Jun 2015The health and vigour of honeybee colonies are threatened by numerous parasites (such as and spp.) and pathogens, including viruses, bacteria, protozoa. Among honeybee... (Review)
Review
The health and vigour of honeybee colonies are threatened by numerous parasites (such as and spp.) and pathogens, including viruses, bacteria, protozoa. Among honeybee pathogens, viruses are one of the major threats to the health and well-being of honeybees and cause serious concern for researchers and beekeepers. To tone down the threats posed by these invasive organisms, a better understanding of bee viral infections will be of crucial importance in developing effective and environmentally benign disease control strategies. Here we summarize recent progress in the understanding of the morphology, genome organization, transmission, epidemiology and pathogenesis of eight honeybee viruses: Deformed wing virus (DWV) and Kakugo virus (KV); Sacbrood virus (SBV); Black Queen cell virus (BQCV); Acute bee paralysis virus (ABPV); Kashmir bee virus (KBV); Israeli Acute Paralysis Virus (IAPV); Chronic bee paralysis virus (CBPV). The review has been designed to provide researchers in the field with updated information about honeybee viruses and to serve as a starting point for future research.
PubMed: 27800411
DOI: 10.4081/ijfs.2015.5364 -
Journal of Fungi (Basel, Switzerland) Apr 2022Nosemosis is a disease triggered by the single-celled spore-forming fungi and , which can cause extensive colony losses in honey bees ( L.). Fumagillin is an effective... (Review)
Review
Nosemosis is a disease triggered by the single-celled spore-forming fungi and , which can cause extensive colony losses in honey bees ( L.). Fumagillin is an effective antibiotic treatment to control nosemosis, but due to its toxicity, it is currently banned in many countries. Accordingly, in the beekeeping sector, there is a strong demand for alternative ecological methods that can be used for the prevention and therapeutic control of nosemosis in honey bee colonies. Numerous studies have shown that plant extracts, RNA interference (RNAi) and beneficial microbes could provide viable non-antibiotic alternatives. In this article, recent scientific advances in the biocontrol of nosemosis are summarized.
PubMed: 35628680
DOI: 10.3390/jof8050424 -
Folia Parasitologica Sep 2020Hexokinase (HXK) is the first key enzyme in the glycolytic pathway and plays an extremely important role in energy metabolism. By searching the microsporidian database,...
Hexokinase (HXK) is the first key enzyme in the glycolytic pathway and plays an extremely important role in energy metabolism. By searching the microsporidian database, we found a sequence (NBO_27g0008) of Nosema bombycis Nägali, 1857 with high similarity to hexokinase-2, and named it as NbHXK2. The NbHXK2 gene has 894 bp and encodes 297 amino acids with 34.241 kD molecular weight and 5.26 isoelectric point. NbHXK2 contains 31 phosphorylation sites and 4 potential N-glycosylation sites with signal peptides and no transmembrane domain. Multiple sequence alignment showed that NbHXK2 shares more than 40% amino acid identity with that of other microsporidia, and the homology with hexokinase-2 of Nosema tyriae Canning, Curry, Cheney, Lafranchi-Tristem, Kawakami, Hatakeyama, Iwano et Ishihara, 1999, Nosema pyrausta (Paillot, 1927) and Nosema ceranae Fries, Feng, da Silva, Slemenda et Pieniazek, 1996 was 89.17%, 87.82% and 69.86%, respectively. Phylogenetic analysis based on the amino acid sequence of hexokinase showed that all microsporidia cluster together in the same clade, and are far away from animals, plants and fungi, and that N. bombycis is closely related to N. tyriae; N. pyrausta; N. ceranae and Nosema apis Zander, 1909. Immunolocalisation with the prepared polyclonal antibody showed that NbHXK2 was mainly distributed in the cytoplasm and plasmalemma in proliferative, sporulation stage and mature spore of N. bombycis. qRT-PCR assay showed that the NbHXK2 expressed at higher level during spore germination and at early stage of proliferation. These results indicate that N. bombycis may use its own glycolytic pathways to supply energy for infection and development, especially germination and in the early stage of proliferation, and acquire energy from the host through certain ways as well.
Topics: Amino Acid Sequence; Fungal Proteins; Hexokinase; Nosema; Phylogeny; Sequence Alignment
PubMed: 33021201
DOI: 10.14411/fp.2020.023 -
PLoS Pathogens Dec 2023Microsporidia are a group of obligate intracellular parasites that infect almost all animals, causing serious human diseases and major economic losses to the farming...
Microsporidia are a group of obligate intracellular parasites that infect almost all animals, causing serious human diseases and major economic losses to the farming industry. Nosema bombycis is a typical microsporidium that infects multiple lepidopteran insects via fecal-oral and transovarial transmission (TOT); however, the underlying TOT processes and mechanisms remain unknown. Here, we characterized the TOT process and identified key factors enabling N. bombycis to invade the ovariole and oocyte of silkworm Bombyx mori. We found that the parasites commenced with TOT at the early pupal stage when ovarioles penetrated the ovary wall and were exposed to the hemolymph. Subsequently, the parasites in hemolymph and hemolymph cells firstly infiltrated the ovariole sheath, from where they invaded the oocyte via two routes: (I) infecting follicular cells, thereby penetrating oocytes after proliferation, and (II) infecting nurse cells, thus entering oocytes following replication. In follicle and nurse cells, the parasites restructured and built large vacuoles to deliver themselves into the oocyte. In the whole process, the parasites were coated with B. mori vitellogenin (BmVg) on their surfaces. To investigate the BmVg effects on TOT, we suppressed its expression and found a dramatic decrease of pathogen load in both ovarioles and eggs, suggesting that BmVg plays a crucial role in the TOT. Thereby, we identified the BmVg domains and parasite spore wall proteins (SWPs) mediating the interaction, and demonstrated that the von Willebrand domain (VWD) interacted with SWP12, SWP26 and SWP30, and the unknown function domain (DUF1943) bound with the SWP30. When disrupting these interactions, we found significant reductions of the pathogen load in both ovarioles and eggs, suggesting that the interplays between BmVg and SWPs were vital for the TOT. In conclusion, our study has elucidated key aspects about the microsporidian TOT and revealed the key factors for understanding the molecular mechanisms underlying this transmission.
Topics: Animals; Humans; Vitellogenins; Spores, Fungal; Nosema; Bombyx
PubMed: 38060601
DOI: 10.1371/journal.ppat.1011859 -
Insects Aug 2022is one of the fungal parasites of . It causes physical and behavioral effects in honey bees. However, only a few studies have reported on gene expression profiling...
is one of the fungal parasites of . It causes physical and behavioral effects in honey bees. However, only a few studies have reported on gene expression profiling during infection. In this study, the transcriptome profile of mature spores at each time point of infection (5, 10, and 20 days post-infection, d.p.i.) were investigated. Based on the transcriptome and expression profile analysis, a total of 878, 952, and 981 differentially expressed genes (DEGs) (fold change ≥ 2 or ≤ -2) were identified in spores (NcSp) at 5 d.p.i., 10 d.p.i., and 20 d.p.i., respectively. Moreover, 70 upregulated genes and 340 downregulated genes among common DEGs (so-called common DEGs) and 166 stage-specific genes at each stage of infection were identified. The Gene Ontology (GO) analysis indicated that the DEGs and corresponding common DEGs are involved in the functions of cytosol (GO:0005829), cytoplasm (GO:0005737), and ATP binding (GO:0005524). Furthermore, the pathway analysis found that the DEGs and common DEGs are involved in metabolism, environmental information processing, and organismal systems. Four upregulated common DEGs with higher fold-change values, highly associated with spore proteins and transcription factors, were selected for validation. In addition, the stage-specific genes are highly involved in the mechanism of pre-mRNA splicing according to GO enrichment analysis; thus, three of them showed high expression at each d.p.i. and were also subjected to validation. The relative gene expression levels showed a similar tendency as the transcriptome predictions at different d.p.i., revealing that the gene expression of during infection may be related to the mechanism of gene transcription, protein synthesis, and structural proteins. Our data suggest that the gene expression profiling of at the transcriptomic level could be a reference for the monitoring of nosemosis at the genetic level.
PubMed: 36005340
DOI: 10.3390/insects13080716