Phenoloxidase activity and haemolymph cytology in honeybees challenged with a virus suspension (deformed wings virus DWV) or phosphate buffered suspension (PBS)

Millanta, Francesca; Sagona, Simona; Mazzei, Maurizio; Forzan, Mario; Poli, Alessandro; Felicioli, Antonio

doi:10.1590/0103-8478cr20180726

Cited by 8 publications

(5 citation statements)

References 27 publications

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“…Treatment group differences in dissemination may indicate that replication of latent viral infections may not only be induced by non-viral stressors but also depend on virus variant and bee immune responses (Anderson and Gibbs, 1988;Yang and Cox-Foster, 2005;Boncristiani et al, 2013;Kuster et al, 2014;Khongphinitbunjong et al, 2015;Annoscia et al, 2019;Remnant et al, 2019;Tehel et al, 2019;Mookhploy et al, 2021). For instance, phenol oxidase and antimicrobial peptides have been shown to be upregulated when bees were injected with DWV but not PBS compared to controls, whereas hemocyte counts increased following both DWV and PBS injections (Ryabov et al, 2016;Millanta et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

Honey Bee Genetic Stock Determines Deformed Wing Virus Symptom Severity but not Viral Load or Dissemination Following Pupal Exposure

et al. 2022

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Honey bees exposed to Varroa mites incur substantial physical damage in addition to potential exposure to vectored viruses such as Deformed wing virus (DWV) that exists as three master variants (DWV-A, DWV-B, and DWV-C) and recombinants. Although mite-resistant bees have been primarily bred to mitigate the impacts of Varroa mites, mite resistance may be associated with increased tolerance or resistance to the vectored viruses. The goal of our study is to determine if five honey bee stocks (Carniolan, Italian, Pol-Line, Russian, and Saskatraz) differ in their resistance or tolerance to DWV based on prior breeding for mite resistance. We injected white-eyed pupae with a sublethal dose (105) of DWV or exposed them to mites and then evaluated DWV levels and dissemination and morphological symptoms upon adult emergence. While we found no evidence of DWV resistance across stocks (i.e., similar rates of viral replication and dissemination), we observed that some stocks exhibited reduced symptom severity suggestive of differential tolerance. However, DWV tolerance was not consistent across mite-resistant stocks as Russian bees were most tolerant, while Pol-Line exhibited the most severe symptoms. DWV variants A and B exhibited differential dissemination patterns that interacted significantly with the treatment group but not bee stock. Furthermore, elevated DWV-B levels reduced adult emergence time, while both DWV variants were associated with symptom likelihood and severity. These data indicate that the genetic differences underlying bee resistance to Varroa mites are not necessarily correlated with DWV tolerance and may interact differentially with DWV variants, highlighting the need for further work on mechanisms of tolerance and bee stock–specific physiological interactions with pathogen variants.

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Section: Discussionmentioning

confidence: 99%

Honey Bee Genetic Stock Determines Deformed Wing Virus Symptom Severity but not Viral Load or Dissemination Following Pupal Exposure

et al. 2022

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“…The hemocyte concentration is an important indicator that reflects an insect's ability to resist entomopathogens. Viral infections induce cellular defense reactions (Millanta et al, 2019). It was found that the hemocyte concentrations of S. exigua larvae infected with the virus varied with the plant species consumed (Wang et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

“…Studies have reported that hemolymph PO activity of lepidopteran larvae are affected by viral infection. For example, Millanta et al (2019) found that virustreated honeybees had higher PO activity than the control. Li et al (2021) reported that the PO activity of S. exigua larvae infected with the virus was significantly increased.…”

Section: Discussionmentioning

confidence: 99%

Effect of plant phenolic compounds on the hemocyte concentration and antioxidant enzyme activity in Hyphantria cunea (Drury, 1773) (Lepidoptera: Arctiidae) larvae infected by Hyphantria cunea granulovirus

Yanar¹,

Topkara²,

Mercan³

et al. 2022

Turkish Journal of Entomology

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The aim of this study was to determine the effects of phenolic substances of four plants (apple, mulberry, plum and walnut) on hemocyte concentrations and antioxidant enzyme activity of Hyphantria cunea (Drury, 1773) (Lepidoptera: Arctiidae) larvae infected with Hyphantria cunea granulovirus and uninfected. The plants used in this study were collected in Bafra, Samsun, Turkey in 2019. The phenolic concentrations of the leaves of these plants were determined. Then, the effect of these phenolic on hemocyte concentrations and antioxidant enzyme activity of infected and uninfected larvae were determined. The hemocyte concentrations of all groups increased with virus infection. The concentration of malondialdehyde decreased in all groups as a result of viral infection. The highest superoxide dismutase and catalase activities among both infected and uninfected larvae were in the plum groups with the highest concentration of chlorogenic acid, the lowest glutathione peroxidase activity was also in these groups. All this showed that different phenolic concentrations of host plants affected the hemocyte concentrations and antioxidant enzyme activity of H. cunea larvae.

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“…Phenoloxidase is expressed as prophenoloxidase (zymogen), which must be activated by serine proteinases, because some of the intermediates of the enzymatic cascade (quinones) are dangerous for the organism itself [32,33]. It has been found that in old honeybee workers the rise of PO activity compensate for the natural loss of haemocytes [34].…”

Section: Introductionmentioning

confidence: 99%

Effect of Oral Administration of 1,3-1,6 β-Glucans in DWV Naturally Infected Newly Emerged Bees (Apis mellifera L.)

Felicioli

Forzan

Sagona

et al. 2020

Veterinary Sciences

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Honeybee pathogens have an important role in honeybee colony mortality and colony losses; most of them are widely spread and necessitate worldwide solutions to contrast honeybee’s decline. Possible accepted solutions to cope with the spread of honeybee’s pathogens are focused on the study of experimental protocols to enhance the insect’s immune defenses. Honeybee’s artificial diet capable to stimulate the immune system is a promising field of investigation as ascertained by the introduction of 1,3-1,6 β-glucans as a dietary supplement. In this work, by collecting faecal samples of honeybees exposed to different dietary conditions of 1,3-1,6 β-glucans (0.5% and 2% w/w), it has been possible to investigate the Deformed wing virus (DWV) viral load kinetic without harming the insects. Virological data obtained by a one-step TaqMan RT-PCR highlighted the ability of 1,3-1,6 β-glucans to reduce the viral load at the 24th day of rearing. The results indicated that the diet supplemented with 1,3-1,6 β-glucans was associated with a dose-dependent activation of phenoloxidase. The control group showed a higher survival rate than the experimental groups. This research confirmed 1,3-1,6 β-glucans as molecules able to modulate honeybees’ defense pathways, and this is the first report in which the kinetic of DWV infection in honeybee faeces has been monitored by a RT-qPCR.

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Phenoloxidase activity and haemolymph cytology in honeybees challenged with a virus suspension (deformed wings virus DWV) or phosphate buffered suspension (PBS)

Cited by 8 publications

References 27 publications

Honey Bee Genetic Stock Determines Deformed Wing Virus Symptom Severity but not Viral Load or Dissemination Following Pupal Exposure

Honey Bee Genetic Stock Determines Deformed Wing Virus Symptom Severity but not Viral Load or Dissemination Following Pupal Exposure

Effect of plant phenolic compounds on the hemocyte concentration and antioxidant enzyme activity in Hyphantria cunea (Drury, 1773) (Lepidoptera: Arctiidae) larvae infected by Hyphantria cunea granulovirus

Effect of Oral Administration of 1,3-1,6 β-Glucans in DWV Naturally Infected Newly Emerged Bees (Apis mellifera L.)

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