No abstract

The unicellular spore-forming parasites Nosema apis and Nosema ceranae are considered to be one of the causes of increased honey bee mortality in recent years. These pathogens attack their honey bee hosts through their gut, causing changes in behavioral stress responses and possibly resulting in decreased honey yield and increased honey bee mortality. The present study aimed to determine the prevalence of Nosema spp. (nosemosis) in Estonia and Latvia, as well as the persistence of the disease in previously infected hives. Currently, N. ceranae is considered the most virulent species and is predominant worldwide. However, in some regions, usually with colder climates, N. apis is still prevalent. To achieve better disease control, it is important to determine the species distribution. For this purpose, we selected 30 apiaries in Estonia and 60 in Latvia that were positive for Nosema spp. in the EPILOBEE (2012–2014) study, which was 5 years prior to the present study. The results show that, while both species are present in Estonia and Latvia, N. apis is dominant in Estonia (43%), and N. ceranae is dominant in Latvia (47%). We also found that the pathogens are very persistent, since 5 years later, only 33% of infected apiaries in Estonia and 20% of infected apiaries in Latvia, we could not detect any pathogens at the time of sampling.

The present study investigates the synthesis of silver nanoparticles (Ag NP) using Artemisia vulgaris tincture and their enhanced antimicrobial activity against different bacterial strains. The Ag NP were characterized using UV-Vis spectroscopy, FTIR, and XRD. Their antibacterial activity was also assessed against Escherichia coli, Staphylococcus aureus, Streptococcus uberis, Pseudomonas aeruginosa, Listeria monocytogenes and Corynebacterium spp. The results demonstrated that the size of the inhibition zone increased with increase in Ag NP concentration. Additionally, the type of bacterial strain also had an effect on the size of the inhibition zones.

The present study deals with the green synthesis of ZnO nanoparticles using Thuja tincture as a solvent and two different Zn precursors. The crystallinity of the as-synthesized ZnO nanoparticles was investigated by XRD. The biomolecules bonded to the surfaces of the nanoparticles were assessed by Fourier transform infrared spectroscopy. The band gap and defects in these nanoparticles were investigated by UV-Vis and photoluminescence spectroscopies, respectively. The antibacterial properties of these nanoparticles were also investigated against Escherichia coli.