The role of 10-hydroxy-Δ2-decenoic acid in the formation of fibrils of the major royal jelly protein 1/apisimin/24-methylenecholesterol complex isolated from honey bee (Apis mellifera) royal jelly

Please read abstract in the article.https://www.eje.cz/artkey/inf-990000-2100_Home.phphj2023Zoology and Entomolog

More than royal food - Major royal jelly protein genes in sexuals and workers of the honeybee Apis mellifera

BACKGROUND: In the honeybee Apis mellifera, female larvae destined to become a queen are fed with royal jelly, a secretion of the hypopharyngeal glands of young nurse bees that rear the brood. The protein moiety of royal jelly comprises mostly major royal jelly proteins (MRJPs) of which the coding genes (mrjp1-9) have been identified on chromosome 11 in the honeybee’s genome. RESULTS: We determined the expression of mrjp1-9 among the honeybee worker caste (nurses, foragers) and the sexuals (queens (unmated, mated) and drones) in various body parts (head, thorax, abdomen). Specific mrjp expression was not only found in brood rearing nurse bees, but also in foragers and the sexuals. CONCLUSIONS: The expression of mrjp1 to 7 is characteristic for the heads of worker bees, with an elevated expression of mrjp1-4 and 7 in nurse bees compared to foragers. Mrjp5 and 6 were higher in foragers compared to nurses suggesting functions in addition to those of brood food proteins. Furthermore, the expression of mrjp9 was high in the heads, thoraces and abdomen of almost all female bees, suggesting a function irrespective of body section. This completely different expression profile suggests mrjp9 to code for the most ancestral major royal jelly protein of the honeybee.AB was supported by a fellowship of the Prorectorate for Research and Young Academics of the Martin-Luther-University Halle- Wittenberg. The DFG provided financial support for chemicals and supplies (RFAM).http://www.frontiersinzoology.com/content/10/1/72am201

Comparative analyses of the major royal jelly protein gene cluster in three Apis species with long amplicon sequencing

The western honeybee, Apis mellifera is a prominent model organism in the field of sociogenomics and a recent upgrade substantially improved annotations of the reference genome. Nevertheless, genome assemblies based on short-sequencing reads suffer from problems in regions comprising e.g. multi-copy genes. We used single-molecule nanopore-based sequencing with extensive read-lengths to reconstruct the organization of the major royal jelly protein (mrjp) region in three species of the genus Apis. Long-amplicon sequencing provides evidence for lineage-specific evolutionary fates of Apis mrjps. Whereas the most basal species, A. florea, seems to encode ten mrjps, different patterns of gene loss and retention were observed for A. mellifera and A. dorsata. Furthermore, we show that a previously reported pseudogene in A. mellifera, mrjp2-like, is an assembly artefact arising from short read sequencing.The German Research Foundation (Deutsche Forschungsgemeinschaft - DFG, Grant MO 373/32-1 to RFAM).http://dnaresearch.oxfordjournals.orgam2017Zoology and Entomolog

Antiprion drugs 6-aminophenanthridine and guanabenz reduce PABPN1 toxicity and aggregation in oculopharyngeal muscular dystrophy

Oculopharyngeal muscular dystrophy (OPMD) is an adult-onset syndrome characterized by progressive degeneration of specific muscles. OPMD is caused by extension of a polyalanine tract in poly(A) binding protein nuclear 1 (PABPN1). Insoluble nuclear inclusions form in diseased muscles. We have generated a Drosophila model of OPMD that recapitulates the features of the disorder. Here, we show that the antiprion drugs 6-aminophenanthridine (6AP) and guanabenz acetate (GA), which prevent formation of amyloid fibers by prion proteins in cell models, alleviate OPMD phenotypes in Drosophila, including muscle degeneration and nuclear inclusion formation. The large ribosomal RNA and its activity in protein folding were recently identified as a specific cellular target of 6AP and GA. We show that deletions of the ribosomal DNA locus reduce OPMD phenotypes and act synergistically with sub-effective doses of 6AP. In a complementary approach, we demonstrate that ribosomal RNA accelerates in vitro fibril formation of PABPN1 N-terminal domain. These results reveal the conserved role of ribosomal RNA in different protein aggregation disorders and identify 6AP and GA as general anti-aggregation molecules

How honeybees defy gravity with royal jelly to raise queens

The female sex in honeybees (Apis spp.) comprises a reproductive queen and a sterile worker caste. Nurse bees feed all larvae progressively with a caste-specific food jelly until the prepupal stage. Only those larvae that are exclusively fed a large amount of royal jelly (RJ) develop into queens [1]. RJ is a composite secretion of two specialized head glands: the mandibular glands, which produce mainly fatty acids [2], and the hypopharyngeal glands, which contribute proteins, primarily belonging to the major royal jelly protein (MRJP) family [3]. Past research on RJ has focused on its nutritional function and overlooked its central role with regard to the orientation of the larva in the royal brood cell. Whereas workers are reared in the regular horizontal cells of the comb, the queen cells are specifically built outside of the normal comb area to accommodate for the larger queen [4, 5]. These cells hang freely along the bottom of the comb and are vertically oriented, opening downward [6]. Queen larvae are attached by their RJ diet to the cell ceiling. Thus, the physical properties of RJ are central to successful retention of larvae in the cell. Here, we show that the main protein of RJ (MRJP1) polymerizes in complex with another protein, apisimin, into long fibrous structures that build the basis for the high viscosity of RJ to hold queen larvae on the RJ surface.Document S1. Figures S1–S4 and Table S1.Data S1. Mass Spectrometric Identification of OligoMRJP1, MonoMRJP1, and Apisimin, Related to Figure 1.The German Research Foundation (Deutsche Forschungsgemeinschaft - DFG, grant MO 373/32-1 to R.F.A.M.) and an ERASMUS + exchange program grant to C.I.M.http://www.sciencedirect.com/science/journal/09609822am2018Zoology and Entomolog

Oxidative stress and senescence in social insects:A significant but inconsistent link?

The life-prolonging effects of antioxidants have long entered popular culture, but the scientific community still debates whether free radicals and the resulting oxidative stress negatively affect longevity. Social insects are intriguing models for analysing the relationship between oxidative stress and senescence because life histories differ vastly between long-lived reproductives and the genetically similar but short-lived workers. Here, we present the results of an experiment on the accumulation of oxidative damage to proteins, and a comparative analysis of the expression of 20 selected genes commonly involved in managing oxidative damage, across four species of social insects: a termite, two bees and an ant. Although the source of analysed tissue varied across the four species, our results suggest that oxidative stress is a significant factor in senescence and that its manifestation and antioxidant defenses differ among species, making it difficult to find general patterns. More detailed and controlled investigations on why responses to oxidative stress may differ across social species may lead to a better understanding of the relations between oxidative stress, antioxidants, social life history and senescence. This article is part of the theme issue 'Ageing and sociality: why, when and how does sociality change ageing patterns

What is the main driver of ageing in long-lived winter honeybees : antioxidant enzymes, innate immunity, or vitellogenin?

Senescence or ageing in invertebrates is only partly unscrambled. Up to now five different theories deal with explaining the biology of ageing. Most likely physiology, genetic predestination and the impact of the environment form the image of ageing in individuals and groups. Social insects, especially the honeybee Apis mellifera, present the best model system to study developmentally related ageing, because high phenotypic plasticity makes the worker caste useful to dissolve remaining questions. Here, we used long-lived winter honeybee workers and measured transcriptional changes of 14 antioxidative enzymes, immunity and ageing-related (Insulin/insulin-like growth factor signalling-pathway) genes at two time points during hibernation. Additionally, the bees received a bacterial infection to see ageing and infection associated immunity changes. Gene expression levels for each group of target genes revealed that ageing had a much higher impact than the bacterial infections, notably for immunity related genes. Antimicrobial peptide and antioxidative enzyme genes were significantly up-regulated in aged worker honeybees independent of bacterial infections. Vitellogenin and IlP-1, known ageing markers, were contrary regulated with increasing vitellogenin levels during ageing. The increased antioxidative enzyme and antimicrobial peptide gene expression may have a positive and also protective effect during ageing in hibernating worker honeybees.http://biomedgerontology.oxfordjournals.org/hb201

Oxidative stress and senescence in social insects : a significant but inconsistent link?

The life-prolonging effects of antioxidants have long entered popular culture, but the scientific community still debates whether free radicals and the resulting oxidative stress negatively affect longevity. Social insects are intriguing models for analysing the relationship between oxidative stress and senescence because life histories differ vastly between long-lived reproductives and the genetically similar but short-lived workers. Here, we present the results of an experiment on the accumulation of oxidative damage to proteins, and a comparative analysis of the expression of 20 selected genes commonly involved in managing oxidative damage, across four species of social insects: a termite, two bees and an ant. Although the source of analysed tissue varied across the four species, our results suggest that oxidative stress is a significant factor in senescence and that its manifestation and antioxidant defenses differ among species, making it difficult to find general patterns. More detailed and controlled investigations on why responses to oxidative stress may differ across social species may lead to a better understanding of the relations between oxidative stress, antioxidants, social life history and senescence. This article is part of the theme issue ‘Ageing and sociality: why, when and how does sociality change ageing patterns?’The German Research Foundation and the Technische Universität Dresden Zukunftskonzept funded from the Excellence Initiative by the German Federal and State Governments.http://rstb.royalsocietypublishing.orgam2022Zoology and Entomolog

Influence of the Stability of a Fused Protein and Its Distance to the Amyloidogenic Segment on Fibril Formation

Conversion of native proteins into amyloid fibrils is irreversible and therefore it is difficult to study the interdependence of conformational stability and fibrillation by thermodynamic analyses. Here we approached this problem by fusing amyloidogenic poly-alanine segments derived from the N-terminal domain of the nuclear poly (A) binding protein PABPN1 with a well studied, reversibly unfolding protein, CspB from Bacillus subtilis. Earlier studies had indicated that CspB could maintain its folded structure in fibrils, when it was separated from the amyloidogenic segment by a long linker. When CspB is directly fused with the amyloidogenic segment, it unfolds because its N-terminal chain region becomes integrated into the fibrillar core, as shown by protease mapping experiments. Spacers of either 3 or 16 residues between CspB and the amyloidogenic segment were not sufficient to prevent this loss of CspB structure. Since the low thermodynamic stability of CspB (ΔGD = 12.4 kJ/mol) might be responsible for unfolding and integration of CspB into fibrils, fusions with a CspB mutant with enhanced thermodynamic stability (ΔGD = 26.9 kJ/mol) were studied. This strongly stabilized CspB remained folded and prevented fibril formation in all fusions. Our data show that the conformational stability of a linked, independently structured protein domain can control fibril formation

Transcriptional Control of Honey Bee (Apis mellifera) Major Royal Jelly Proteins by 20-Hydroxyecdysone

One of the first tasks of worker honey bees (Apis mellifera) during their lifetime is to feed the larval offspring. In brief, young workers (nurse bees) secrete a special food jelly that contains a large amount of unique major royal jelly proteins (MRJPs). The regulation of mrjp gene expression is not well understood, but the large upregulation in well-fed nurse bees suggests a tight repression until, or a massive induction upon, hatching of the adult worker bees. The lipoprotein vitellogenin, the synthesis of which is regulated by the two systemic hormones 20-hydroxyecdysone and juvenile hormone, is thought to be a precursor for the production of MRJPs. Thus, the regulation of mrjp expression by the said systemic hormones is likely. This study focusses on the role of 20-hydroxyecdysone by elucidating its effect on mrjp gene expression dynamics. Specifically, we tested whether 20-hydroxyecdysone displayed differential effects on various mrjps. We found that the expression of the mrjps (mrjp1–3) that were finally secreted in large amounts into the food jelly, in particular, were down regulated by 20-hydroxyecdysone treatment, with mrjp3 showing the highest repression value