Heat stress affects oogenesis differently in wild-type Drosophila virilis and a mutant with altered juvenile hormone and 20-hydroxyecdysone levels

The link between reproduction and environmental signals is poorly understood at the physiological, genetic and molecular levels. We describe a mutant strain of Drosophila virilis that has altered responses to heat stress. Heat stress in wild-type females results in oocyte maturation delays, degradation of early vitellogenic egg chambers, inhibition of yolk protein gene expression in follicle cells and accumulation of mature oocytes. The mutant females have increased levels of ecdysteroids and decreased juvenile hormone degradation, and show all of the heat-stress-induced reproductive effects observed in wild-type flies, without exposure to heat stress. During oogenesis in mutant females following heat stress there is an increase in early vitellogenic oocyte degradation and some degradation of late egg chambers. 20-Hydroxyecdysone levels, but not juvenile hormone degradation, change following heat stress in mutant females.     

Analysis of the Drosophila melanogaster anti‐ovarian response to honey bee queen mandibular pheromone

Queen mandibular pheromone (QMP) is a potent reproductive signal to which honey bee workers respond by suppressing their ovaries and adopting alloparental roles within the colony. This anti‐ovarian effect of QMP on workers can, surprisingly, be induced in other insects, including fruit flies, in which females exposed to synthetic QMP develop smaller ovaries with fewer eggs. In this study, we use the Drosophila melanogaster model to identify the components of synthetic QMP required for the anti‐ovarian effect. We found that virgin females respond strongly to 9‐oxo‐2‐decenoic acid and 10‐hydroxy‐2‐decenoic acid (10HDA), suggesting that the decenoic acid components of QMP are essential for the anti‐ovarian response. Further, a nuclear factor of activated T‐cells reporter system revealed neurones expressing the olfactory receptors Or‐56a, Or‐49b and Or‐98a are activated by QMP in the antenna. In addition, we used olfactory receptor GAL4 drivers and a neuronal activator (a neuronal activating bacterial sodium channel) to test whether the candidate neurones are potential labelled lines for a decenoic acid response. We identified Or‐49b as a potential candidate receiver of the 10HDA signal. Finally, the anti‐ovarian response to synthetic QMP is not mediated by decreasing the titre of the reproductive hormones ecdysone and juvenile hormone.     

Regulation of the brain dopaminergic system by juvenile hormone in honey bee males (Apis mellifera L.)

Dopamine (DA) and juvenile hormone (JH) are multifunctional regulators of behaviour in social insects, with distinct effects across species and even between different dominance positions within the same species. We examined the effects of JH on the brain dopaminergic system in honey bee males to investigate the potential relationship between JH and DA within Apis mellifera. Both DA content and the expression of three DA receptor genes (Amdop1, Amdop2 and Amdop3) increased in the male honey bee brain from day 4 to day 8 after emergence. Treatment of 4-day-old males with a JH analogue (methoprene, JHA) enhanced brain DA levels. Brain expression of Amdop1 was also enhanced by JHA but not by a DA receptor agonist 2-amino 6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (6,7-ADTN), indicating that Amdop1 up-regulation was not mediated by increased DA receptor stimulation. Furthermore, Amdop1 expression was still enhanced when JHA was co-applied with the DA receptor antagonist cis-(Z)-flupenthixol. Expression levels of Amdop2 and Amdop3 were not altered by JHA, 6,7-ADTN or by JHA plus the DA receptor antagonist. Regulation of the brain dopaminergic system by JH, as observed in solitary species, is conserved in male honey bees but not in female honey bees and other advanced eusocial insects.     

Nosema ceranae alters a highly conserved hormonal stress pathway in honeybees

Nosema ceranae, an emerging pathogen of the western honeybee (Apis mellifera), is implicated in recent pollinator losses and causes severe energetic stress. However, whether precocious foraging and accelerated behavioural maturation in infected bees are caused by the infection itself or via indirect energetic stress remains unknown. Using a combination of nutritional and infection treatments, we investigated how starvation and infection alters the regulation of adipokinetic hormone (AKH) and octopamine, two highly conserved physiological pathways that respond to energetic stress by mobilizing fat stores and increasing search activity for food. Although there was no response from AKH when bees were experimentally infected with N. ceranae or starved, supporting the notion that honeybees have lost this pathway, there were significant regulatory changes in the octopamine pathway. Significantly, we found no evidence of acute energetic stress being the only cause of symptoms associated with N. ceranae infection. Therefore, the parasite itself appears to alter regulatory components along a highly conserved physiological pathway in an infection‐specific manner. This indicates that pathogen‐induced behavioural alteration of chronically infected bees should not just be viewed as a coincidental short‐term by‐product of pathogenesis (acute energetic stress) and may be a result of a generalist manipulation strategy to obtain energy for reproduction.     

Absence of juvenile hormone signalling regulates the dynamic expression profiles of nutritional metabolism genes during diapause preparation in the cabbage beetle Colaphellus bowringi

Temperate insects have evolved diapause, a period of programmed developmental arrest during specific life stages, to survive unfavourable conditions. During the diapause preparation phase (DPP), diapause‐destined individuals generally store large amounts of fat by regulating nutrition distribution for the energy requirement during diapause maintenance and postdiapause development. Although nutritional patterns during the DPP have been investigated at physiological and biochemical levels in many insects, it remains largely unknown how nutritional metabolism is regulated during the DPP at molecular levels. We used RNA sequencing to compare gene expression profiles of adult female cabbage beetles Colaphellus bowringi during the preoviposition phase (POP) and the DPP. Most differentially expressed genes were involved in specific metabolic pathways during the DPP. Genes related to lipid and carbohydrate metabolic pathways were clearly highly expressed during the DPP, whereas genes related to protein metabolic pathways were highly expressed during the POP. Hormone challenge and RNA interference experiments revealed that juvenile hormone via its nuclear receptor methoprene‐tolerant mediated the expression of genes associated with nutritional metabolism during the DPP. This work not only sheds light on the mechanisms of diapause preparation, but also provides new insights into the molecular basis of environmental plasticity in insects.     

Molecular characterization of a gene encoding juvenile hormone esterase in the red flour beetle,Tribolium castaneum

Juvenile hormone esterases (JHEs) are required for the degradation of juvenile hormones (JHs) in insects. Here, we report the cloning and analysis of the jhe gene in the red flour beetle, Tribolium castaneum, a model insect of Coleoptera. The Tcjhe gene was strongly expressed at the final instar larva, as would be expected if it functioned to decrease the JH titer at this stage. A recombinant TcJHE protein efficiently degraded JH III, suggesting that the enzyme functions in vivo as a JH‐specific degradation enzyme. This is the first report describing the developmental expression profile of the jhe gene whose enzymatic activity was shown in Coleoptera, and the new data reported here will aid elucidation of the mechanism of JH titer regulation in insects.     

单侧入路PKP治疗胸腰椎骨质疏松性骨折的效果及对患者创伤应激反应、骨代谢指标的影响

目的 探讨单侧入路经皮椎体后凸成形术(PKP)治疗胸腰椎骨质疏松性骨折的效果.方法 选取2019年1月至2021年1月我院收治的300例胸腰椎骨质疏松性骨折患者,以抽签法按单双号分组形式随机将其分为对照组和观察组,各150例.对照组采用双侧入路PKP治疗,观察组采用单侧入路PKP治疗.比较两组的治疗效果.结果 术后1 ...