Use of Aloe Vera Gel as Media to Assess Antimicrobial Activity and Development of Antimicrobial Nanocomposites.

Antimicrobial resistance is a menace to public health on a global scale. In this regard, nanomaterials exhibiting antimicrobial properties represent a promising solution. Both metal and metal oxide nanomaterials are suitable candidates, even though their mechanisms of action vary. Multiple antimicrobial mechanisms can occur simultaneously or independently; this includes either direct contact with the pathogens, nanomaterial uptake, oxidative stress, ion release, or any of their combinations. However, due to their specific properties and more particularly fast settling, existing methods to study the antimicrobial properties of nanoparticles have not been specifically adapted in some cases. The development of methodologies that can assess the antimicrobial properties of metallic nanomaterials accurately is necessary. A cost-effective methodology with a straightforward set-up that enables the easy and quick assessment of the antimicrobial properties of metal nanoparticles with high accuracy has been developed. The methodology is also capable of confirming whether the killing mechanism involves ionic diffusion. Finally, Aloe Vera gel showed good properties for use as a medium for the development of antimicrobial ointment.

Variation in the Distribution of Nosema Species in Honeybees (Apis mellifera Linnaeus) between the Neighboring Countries Estonia and Latvia.

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.