Use of Dicranum polysetum extract against Paenibacillus larvae causing American Foulbrood under in vivo and in vitro conditions.

Recent research shows that Dicranum species can be used to ameliorate the negative effects of honeybee bacterial diseases and that novel compounds isolated from these species may have the potential to treat bacterial diseases. This study aimed to investigate the efficacy of Dicranum polysetum Sw. against American Foulbrood using toxicity and larval model. The effectiveness of D. polysetum Sw. ethanol extract in combating AFB was investigated in vitro and in vivo. This study is important in finding an alternative treatment or prophylactic method to prevent American Foulbrood disease in honey bee colonies. Spore and vegetative forms of Paenibacillus larvae PB31B with ethanol extract of D. polysetum were tested on 2040 honey bee larvae under controlled conditions. Total phenolic and flavonoid contents of D. polysetum ethanol extracts were determined as 80.72 mg/GAE(Gallic acid equivalent) and 303.20 µg/mL, respectively. DPPH(2,2-diphenyl-1-picrylhydrazyl) radical scavenging percent inhibition value was calculated as 4.32%. In Spodoptera frugiperda (Sf9) and Lymantria dispar (LD652) cell lines, the cytotoxic activities of D. polysetum extract were below 20% at 50 µg/mL. The extract was shown to considerably decrease infection in the larvae, and the infection was clinically halted when the extract was administered during the first 24 h after spore contamination. The fact that the extract contains potent antimicrobial/antioxidant activity does not reduce larval viability and live weight, and does not interact with royal jelly is a promising development, particularly regarding its use to treat early-stage AFB infection.

Effects of Feeding Honey Bees (Hymenoptera: Apidae) With Industrial Sugars Produced by Plants Using Different Photosynthetic Cycles (Carbon C3 and C4) on the Colony Wintering Ability, Lifespan, and Forage Behavior.

In the study, 130 honey bee colonies fed with different levels (5, 20, and 100 liters/colony) of various industrial commercial sugars, including High-Fructose Corn 85 (Fructose-85), High-Fructose Corn 55 (Fructose-55), Glucose Monohydrate (Glucose), Bee feed, and Sucrose syrups, for 2 mo were compared with colonies fed with no sugar (control) in terms of their colony development of worker bee population, hive weight, wax production, wintering ability, foraging behavior, and lifespan of worker bee. Utilization of industrial sugars by honey bee colonies showed differences in terms of colony performance and behavior parameters. Honey bees did not use Glucose heavily, resulting in 4% increase in worker bee loss in winter and 46% decrease in marked worker bee numbers over time when compared to the control. Sucrose syrup had a positive effect on wintering ability, wax production, and hive weight. While Sucrose had a positive effect (3-4%) on wintering ability, the 100 liters/colony sugar syrups of all other sugars had negative effects (6-15%). Sugars containing high levels of monosaccharide were not used effectively by honey bee colonies, whereas the sugars containing fructose and glucose at rates of 40 and 30% (Bee feed and Fructose-55), were utilized effectively. The lifespan of worker bees decreased over time in the 100 liters/colony of all sugars syrup. In conclusion, except Glucose, other industrial sugars can be used for promoting colonies at the beginning of the season (in spring). Industrial sugars except sucrose should not be used in order to meet carbohydrate needs of the colonies in winter.

Carbonic anhydrase from Apis mellifera: purification and inhibition by pesticides.

Carbonic anhydrase (CA) enzymes have been shown to play an important role in ion transport and in pH regulation in several organisms. Despite this information and the wealth of knowledge regarding the significance of CA enzymes, few studies have been reported about bee CA enzymes and the hazardous effects of chemicals. Using Apis mellifera as a model, this study aimed to determine the risk of pesticides on Apis mellifera Carbonic anhydrase enzyme (Am CA). CA was initially purified from Apis mellifera spermatheca for the first time in the literature. The enzyme was purified with an overall purification of ∼35-fold with a molecular weight of ∼32 kDa. The enzyme was then exposed to pesticides, including tebuconazole, propoxur, carbaryl, carbofuran, simazine and atrazine. The six pesticides dose-dependently inhibited in vitro AmCA activity at low micromolar concentrations. IC50 values for the pesticides were 0.0030, 0.0321, 0.0031, 0.0087, 0.0273 and 0.0165 µM, respectively. The AmCA inhibition mechanism of these compounds is unknown at this moment.

Detection of adulterated honey produced by honeybee (Apis mellifera L.) colonies fed with different levels of commercial industrial sugar (C3 and C4 plants) syrups by the carbon isotope ratio analysis.

In the present study, one hundred pure and adulterated honey samples obtained from feeding honeybee colonies with different levels (5, 20 and 100 L/colony) of various commercial sugar syrups including High Fructose Corn Syrup 85 (HFCS-85), High Fructose Corn Syrup 55 (HFCS-55), Bee Feeding Syrup (BFS), Glucose Monohydrate Sugar (GMS) and Sucrose Sugar (SS) were evaluated in terms of the δ(13)C value of honey and its protein, difference between the δ(13)C value of protein and honey (Δδ(13)C), and C4% sugar ratio. Sugar type, sugar level and the sugar type*sugar level interaction were found to be significant (P<0.001) regarding the evaluated characteristics. Adulterations could not be detected in the 5L/colony syrup level of all sugar types when the δ(13)C value of honey, Δδ(13)C (protein-honey), and C4% sugar ratio were used as criteria according to the AOAC standards. However, it was possible to detect the adulteration by using the same criteria in the honeys taken from the 20 and 100 L/colony of HFCS-85 and the 100L/colony of HFCS-55. Adulteration at low syrup level (20 L/colony) was more easily detected when the fructose content of HFCS syrup increased. As a result, the official methods (AOAC, 978.17, 1995; AOAC, 991.41, 1995; AOAC 998.12, 2005) and Internal Standard Carbon Isotope Ratio Analysis could not efficiently detect the indirect adulteration of honey obtained by feeding the bee colonies with the syrups produced from C3 plants such as sugar beet (Beta vulgaris) and wheat (Triticium vulgare). For this reason, it is strongly needed to develop novel methods and standards that can detect the presence and the level of indirect adulterations.