Mandibular glands secrete 24-methylenecholesterol into honey bee (Apis mellifera) food jelly

A nutritionally complete pollen-replacing diet protects honeybee colonies during stressful commercial pollination-requirement for isofucosterol

A steady supply of nutritionally adequate pollen from diverse flower sources is crucial for honeybee colonies. However, climate instability, large-scale agriculture and the loss of flower-rich landscapes have made this supply scarce and unpredictable, threatening both apiculture and sustainable crop pollination. We developed a nutritionally complete pollen-replacing diet that supports continuous brood production from May to October in colonies without access to pollen. Omitting isofucosterol, the third most abundant sterol in honeybees, causes significant reductions in brood production and neuromuscular dysfunction in adults, identifying isofucosterol as a critical micronutrient. In contrast, omitting 24-methylene cholesterol-the most abundant honeybee sterol-does not significantly affect brood production, and surprisingly, bees remain viable without it. Colonies fed a commercial diet severely declined in brood production after 36 days and died out. In a season-long experiment investigating the commercial pollination of blueberry and sunflower fields, a treatment group fed the complete diet overcame the detrimental effects of nutritional stress, unlike colonies in 'No Diet' and 'Commercial Diet' groups. This study suggests that feeding a complete, pollen-replacing diet to nutritionally stressed colonies can address the root causes of honeybees' growing nutritional deficiencies, supporting their health and their vital pollination services.

Expression of honey bee (Apis mellifera) sterol homeostasis genes in food jelly producing glands of workers

Adult workers of Western honey bees (Apis mellifera L.) acquire sterols from their pollen diet. These food sterols are transported by the hemolymph to peripheral tissues such as the mandibular and the hypopharyngeal glands in the worker bees' heads that secrete food jelly which is fed to developing larvae. As sterols are obligatory components of biological membranes and essential precursors for molting hormone synthesis in insects, they are indispensable to normal larval development. Thus, the study of sterol delivery to larvae is important for a full understanding of honey bee larval nutrition and development. Whereas hypopharyngeal glands only require sterols for their membrane integrity, mandibular glands add sterols, primarily 24-methylenecholesterol, to its secretion. For this, sterols must be transported through the glandular epithelial cells. We have analyzed for the first time in A. mellifera the expression of genes which are involved in intracellular movement of sterols. Mandibular and hypopharyngeal glands were dissected from newly emerged bees, 6-day-old nurse bees that feed larvae and 26-day-old forager bees. The expression of seven genes involved in intracellular sterol metabolism was measured with quantitative real-time PCR. Relative transcript abundance of sterol metabolism genes was significantly influenced by the age of workers and specific genes but not by gland type. Newly emerged bees had significantly more transcripts for six out of seven genes than older bees indicating that the bulk of the proteins needed for sterol metabolism are produced directly after emergence.

Apilarnil ameliorates Bisphenol A-induced testicular toxicity in adult male rats via improving antioxidant potency and PCNA expression

Apilarnil, a bee-derived product originating from drone larvae, offers a range of advantageous properties for both humans and animals. It functions as an antioxidant, provides neuroprotection, boosts fertility, and has antiviral capabilities. Additionally, it is a provider of androgenic hormones. These beneficial functions are supported by its chemical composition, which comprises mineral salts, vitamins, carbs, lipids, hormones, and amino acids. The current study aimed to evaluate the ameliorative effect of apilarnil against Bisphenol A (BPA)-induced testicular toxicity in male adult rats. Forty-eight Wistar albino rats were randomly classified into six groups. The first, second, and third received olive oil, BPA at a dose of 50 mg/kg body weight (bwt), and apilarnil at a dose of 0.6 g/kg bwt, respectively. The fourth, fifth, and sixth groups received apilarnil with, before, or after BPA administration, respectively. Phytochemical analysis using included linear ion trap-ultra-performance liquid chromatography-tandem mass spectrometry (LTQ-UPLC-MS/MS) and global natural products social molecular networking (GNPS) revealed the presence of lysine, 10-hydroxy-(E)-2-dodecenoic acid, apigenin7-glucoside, testosterone, progesterone, and campesterol. BPA administration decreased serum level of follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, glutathione (GSH) concentration, total sperm count, motility, and vitality. Additionally, BPA increased sperm abnormalities, malondialdehyde concentration (MDA), and decreased proliferating cell nuclear antigen (PCNA) expression. The treatment with apilarnil ameliorated BPA reproductive toxicity in rats which was indicated by increased serum testosterone levels, normalized serum levels of FSH and LH, and concentration of MDA and GSH activity. Moreover, apilarnil improved sperm count, motility, morphology, and PCNA expression. Apilarnil was found to enhance reproductive hormones, MDA levels, antioxidant activity, and PCNA expression.