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- Lamei, Sepideh, et al.
(författare)
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Feeding Honeybee Colonies with Honeybee-Specific Lactic Acid Bacteria (Hbs-LAB) Does Not Affect Colony-Level Hbs-LAB Composition or Paenibacillus larvae Spore Levels, Although American Foulbrood Affected Colonies Harbor a More Diverse Hbs-LAB Community
- 2020
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Ingår i: Microbial Ecology. - : Springer Science and Business Media LLC. - 0095-3628 .- 1432-184X. ; 79:3, s. 743-755
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Tidskriftsartikel (refereegranskat)abstract
- The main current methods for controlling American Foulbrood (AFB) in honeybees, caused by the bacterial pathogen Paenibacillus larvae, are enforced incineration or prophylactic antibiotic treatment, neither of which is fully satisfactory. This has led to an increased interest in the natural relationships between the pathogenic and mutualistic microorganisms of the honeybee microbiome, in particular, the antagonistic effects of Honeybee-Specific Lactic Acid Bacteria (hbs-LAB) against P. larvae. We investigated whether supplemental administration of these bacteria affected P. larvae infection at colony level over an entire flowering season. Over the season, the supplements affected neither colony-level hbs-LAB composition nor naturally subclinical or clinical P. larvae spore levels. The composition of hbs-LAB in colonies was, however, more diverse in apiaries with a history of clinical AFB, although this was also unrelated to P. larvae spore levels. During the experiments, we also showed that qPCR could detect a wider range of hbs-LAB, with higher specificity and sensitivity than mass spectrometry. Honeybee colonies are complex super-organisms where social immune defenses, natural homeostatic mechanisms, and microbiome diversity and function play a major role in disease resistance. This means that observations made at the individual bee level cannot be simply extrapolated to infer similar effects at colony level. Although individual laboratory larval assays have clearly demonstrated the antagonistic effects of hbs-LAB on P. larvae infection, the results from the experiments presented here indicate that direct conversion of such practice to colony-level administration of live hbs-LAB is not effective.
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| 2. |
- Lamei, Sepideh, et al.
(författare)
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Improvement of identification methods for honeybee specific Lactic Acid Bacteria; Future approaches
- 2017
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- Honeybees face many parasites and pathogens and consequently rely on a diverse set of individual and group-level defenses to prevent disease. The crop microbiota of Apis mellifera, composed of 13 Lactic Acid Bacterial (LAB) species within the genera Lactobacillus and Bifidobacterium, form a beneficial symbiotic relationship with each other and the honeybee to protect their niche and their host. Possibly playing a vital role in honeybee health, it is important that these honeybee specific Lactic Acid Bacterial (hbs-LAB) symbionts can be correctly identified, isolated and cultured, to further investigate their health promoting properties. We have previously reported successful identification to the strain level by culturedependent methods and we recently sequenced and annotated the genomes of the 13 hbs- LAB. However, the hitherto applied techniques are unfortunately very time consuming, expensive and not ideal when analyzing a vast quantity of samples. In addition, other researchers have constantly failed to identify the 13 hbs-LAB from honeybee samples by using inadequate media and/or molecular techniques based on 16S rRNA gene sequencing with insufficient discriminatory power. The aim of this study was to develop better and more suitable methods for the identification and cultivation of hbs-LAB. We compared currently used bacterial cultivation media and could for the first time demonstrate a significant variation in the hbs-LAB basic requirements for optimal growth. We also present a new bacterial identification approach based on amplicon sequencing of a region of the 16S rRNA gene using the Illumina platform and an error correction software that can be used to successfully differentiate and rapidly identify the 13 hbs-LAB to the strain level.
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| 3. |
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| 4. |
- Lamei, Sepideh
(författare)
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The effect of honeybee-specific lactic acid bacteria on american foulbrood disease of honeybees
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The honeybee, Apis mellifera, is one of the most economically important pollinators and highly valued for its honey and wax production. Managed honeybees occupy an increasingly critical role in agricultural productivity and food security. American foulbrood (AFB) is a highly contagious and destructive bacterial honeybee brood disease caused by Paenibacillus larvae that affects beekeeping worldwide. However, only a minority of bacteria associated with honeybees are harmful. Honeybee-specific Lactic Acid Bacteria (hbs-LAB), a defined group of beneficial bacteria inhabiting the honey crop, have strong antimicrobial properties important for honey production and honeybee health that could be exploited for combating diseases such as AFB. The aim of this thesis was to investigate the effect of hbs-LAB on P. larvae and AFB, both in culture, in individual larval bioassays, and at colony level. First we showed that the laboratory cultivation of the 13 distinct hbs-LAB was significantly improved by the addition of L-cysteine and fructose to the medium and optimized a culture-independent molecular technique for the detection and identification of the individual hbs-LAB species. Secondly the effect of the cell free supernatant, the secretome, from a culture mix of the 13 hbs-LAB species was investigated on P. larvae growth and associated larval mortality. The results showed that this secretome strongly inhibited the multiplication of P. larvae vegetative cells but that spore germination appeared to be unaffected, and that it decreased the mortality of P. larvae infected larvae. Finally it was shown that oral administration of hbs-LAB supplement to honeybee colonies had no influence on colony-level P. larvae spore levels or colony strength. Furthermore, the results showed that although the antibiotic tylosin decreased AFB symptoms in colonies, it had no effect on P. larvae spore levels. In conclusion, the colony-level results do not contradict the antagonistic effects observed in individual larvae in laboratory studies, but rather suggest that supplementary administration of live bacteria may not be the most effective way to harness such effects in a useful application.
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| 5. |
- Lamei, Sepideh, et al.
(författare)
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The secretome of honey bee-specific lactic acid bacteria inhibits Paenibacillus larvae growth
- 2019
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Ingår i: Journal of Apicultural Research. - : Informa UK Limited. - 0021-8839 .- 2078-6913. ; 58:3, s. 405-412
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Tidskriftsartikel (refereegranskat)abstract
- American Foulbrood (AFB) is a particularly pernicious bacterial disease of honey bees due to the extreme persistence of endospores of the causative agent Paenibacillus larvae. These spores are resistant to harsh environmental conditions, unaffected by antimicrobial agents and can remain viable for decades. The germination of the endospore in the larval midgut is the crucial first step leading to infection, followed by vegetative growth, tissue invasion and disease, culminating in spore formation when the host´s nutrients have been exhausted. Therefore, inhibiting spore germination or impeding early vegetative growth would be a highly effective strategy for limiting the impact of AFB. We previously showed that honey bee-specific lactic acid bacteria (hbs–LAB) had a major inhibitory effect on P. larvae both in culture and in larval bioassays. The present study documents the progress towards characterization of compounds, processes and interactions between P. larvae and the hbs–LAB responsible for this inhibitory effect. Firstly, we used an agar diffusion assay and larval infection bioassay to show that most, if not all, of the inhibitory effect was associated with the extracellular fraction (secretome). Secondly, we employed a turbidimetric growth assay to demonstrate that the hbs–LAB secretome strongly inhibited P. larvae vegetative growth, however, probably not by reducing spore germination. The inhibition was similarly effective against both major P. larvae genotypes (ERIC-I and II) in all experiments. The implications of our results for characterization of the secretome and for the management and treatment of AFB and P. larvae are further discussed.
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| 6. |
- Mårtensson, Anders, et al.
(författare)
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Effects of a honeybee lactic acid bacterial microbiome on human nasal symptoms, commensals, and biomarkers
- 2016
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Ingår i: International Forum of Allergy & Rhinology. - : Wiley. - 2042-6984 .- 2042-6976. ; 6:9, s. 956-963
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Lactic acid bacteria (LAB) can restore commensal microbiomes and prevent infections. Arguably, nasal administrations of LAB may therefore be beneficial in chronic rhinosinusitis (CRS). Previous studies have examined effects of topical/nasal LAB in children with secretory otitis media, but little is as yet known about their effects on the human nasal airway. The aim of this pilot study was to examine effects on nasal symptoms and commensal bacteria in healthy subjects of nasal administration of a honeybee LAB microbiome; ie, a mixture of 9 Lactobacillus spp. and 4 Bifidobacterium spp. obtained from the honeybee Apis mellifera. Furthermore, we aimed to assess whether or not the honeybee LAB produced a local inflammatory response.METHODS: Twenty-two healthy subjects received a single administration of honeybee LAB in a sham-controlled, double-blinded, and crossover design. Using questionnaires, microbiological methods, and nasal lavages, they were assessed regarding symptoms, changes to commensal bacteria, and inflammatory products in nasal lavage fluids.RESULTS: The honeybee LAB did not produce any symptoms or other untoward effects. No changes were observed of commensal bacteria by the honeybee LAB, and no inflammatory response was detected (compared to sham); ie, unaffected nasal lavage fluid levels of monocyte chemoattractant protein-1 (MCP-1), interleukin-8 (IL-8), monokine induced by interferon-γ (MIG), interleukin-15 (IL-15), epidermal growth factor (EGF), eotaxin, interferon gamma-induced protein-10 (IP-10), and interleukin-1 receptor antagonist (IL-1RA).CONCLUSION: A single human nasal administration of a honeybee LAB microbiome is well tolerated. Specifically, it does not affect commensal bacteria and does not produce an inflammatory response.
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| 7. |
- Stephan, Jörg, et al.
(författare)
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Honeybee-specific lactic acid bacterial supplements have no effect on American foulbrood infected honeybee colonies
- 2019
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 85:13
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Tidskriftsartikel (refereegranskat)abstract
- Paenibacillus larvae, causative agent of American Foulbrood (AFB), is the primary bacterial pathogen affecting honeybees and beekeeping. The main methods for controlling AFB are incineration of diseased colonies or prophylactic antibiotic treatment (e.g. tylosin), neither of which is fully satisfactory. The search for superior means for controlling AFB has led to an increased interest in the natural relationships between the honeybee pathogenic and mutualistic microorganisms, and in particular the antagonistic effects of honeybee-specific Lactic Acid Bacteria (hbs-LAB) against P. larvae These effects have only been demonstrated on individual larvae in controlled laboratory bioassays. Here we investigated whether supplemental administration of hbs-LAB had a similar beneficial effect on P. larvae infection at colony level. We compared experimentally AFB-infected colonies treated with hbs-LAB supplements to untreated and tylosin-treated colonies, recorded AFB symptoms, bacterial spore levels and two measures of colony health. To account for the complexity of a bee colony we focused on (Bayesian) probabilities and magnitudes of effect sizes. Tylosin reduced AFB disease symptoms but also had a negative effect on colony strength. The tylosin treatment did not, however, affect P. larvae spore levels, and might therefore "mask" the potential for disease. Hbs-LAB tended to reduce brood size in the short-term, but was unlikely to affect AFB symptoms or spores. These results do not contradict demonstrated antagonistic effects of hbs-LAB against P. larvae at the individual bee level, but rather suggest that supplementary administration of hbs-LAB may not be the most effective way to harness these beneficial effects at colony level.ImportanceThe previously demonstrated antagonistic effects of honeybee-derived bacterial microbiota on the infectivity and pathogenicity of P. larvae in laboratory bioassays has identified a possible new approach to AFB control. However, honeybee colonies are complex super-organisms where social immune defenses play a major role in resistance against disease at the colony-level. Few studies have investigated the effect of beneficial microorganisms on bee diseases at the colony level. Effects observed at the individual bee level do not necessarily translate into similar effects at the colony level. This study partially fills this gap by showing that, unlike at individual level, hbs-LAB supplements did not affect AFB symptoms at colony level. The inference is that the mechanisms regulating the honeybee microbial dynamics within a colony are too strong to manipulate positively through supplemental feeding of live hbs-LAB, and that new potential remedies identified through laboratory research have to be tested thoroughly in situ, in colonies.
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