The two sibling species of fruit fly, Drosophila melanogaster and D. simulans (Diptera: Drosophilidae), have long been used as the key model organisms in ecological and evolutionary research. While numerous studies have investigated the thermal responses of these two species, no study has yet systematically compared their response to dietary macronutrient balance. To fill this knowledge gap, we compared how various life-history traits expressed during larval development would response to an array of dietary ratio of protein to carbohydrate (P:C ratio) in these two sibling species. Largely consistent with previous studies, D. melanogaster took longer to complete their larval development and were much larger at adult emergence than D. simulans. For both species, an increase in dietary P:C ratio resulted in improved larval survivorship and faster development. However, the two species showed qualitatively different response to dietary P:C ratio when body mass at adult eclosion was concerned. The body mass of D. melanogaster peaked at an optimal P:C ratio of 1:4, but decreased as the P:C ratio either increased or decreased from this optimum. In marked contrast, the body mass of D. simulans was insensitive to dietary P:C ratio.

The habitat of Drosophila melanogaster is the environment of fruit decay/fermentation which emits high concentrations of chemicals. Our recent studies revealed that D. melanogaster has been evolutionarily adapted to its habitat through tolerance to chemicals and induction of antimicrobial peptides (AMPs) plays an important role for chemical tolerance. To determine the correlation between AMPs and the chemical tolerance pathway, we hypothesized that expression of AMPs is induced by tissue damages or ROS caused by chemical exposure and AMPs activate antioxidant enzymes, thereby inducing chemical tolerance in D. melanogaster. Therefore, in this study, we investigated the induction levels of genes associated with necrosis (EGR and BSK), apoptosis (Dronc, Dcp1, and Drice), antioxidant physiology (SOD1, SOD2, CAT, Trxr1, GstD2, and GstD5), and SAM metabolism (Gnmt and Foxo) in D. melanogaster exposed to three chemicals, 2-phenylethanol, ethanol, and acetic acid. As a result, above genes were induced in chemical-exposed fly, and this supports our hypothesis of chemical tolerance pathway in D. melanogaster.

동물의 종 유지에 있어서 교미행동은 매우 중요한 위치를 차지함. 교미과정에서 수컷의 경우 모든 암컷에 대해 성행동을 보이는반면, 암컷은 가장 적절한 교미의 시기를 정하며, 적절한 수컷을 선택하고 교미행동을 보이기 때문에 암컷의 교미행동을 유도하는 과정은 생물학에서 매우 중요한 의미를 지님. 본 연구에서는 초파리 (Drosophila melanogaster) 전자현미경자료와 총신경망분석 (Connectomics)을 이용하여 초파리 뇌에서 암컷의 교미행동을 조절하는 것으로 알려진 pC1신경의 하부신경 pC1b,c가 성적 성숙과정에서 교미를 하고자 하는 욕구 (sexual drive)를 증가시키는 기능을 하는 것을 처음으로 밝힘. 본 연구에서는 처음으로 pC1b,c 신경 내의 cAMP 수준이 교미의 욕구변화를 보여주는 중요한 물질이라는 것을 밝혔고 cAMP의 수준이 오르기 위해서는 신경펩티 드인 Dh44와 그 수용체 GPCR인 Dh44R1과 Dh44R2가 필요하다는 것을 확인함. 또한 cAMP의 변화는 신경내의 CREBB를 통하여 하위 유전자인 pyx (pyrexia)의 발현을 유도한다는 것을 밝힘. 본 연구로 종 유지 메커니즘을 좀 더 이해할 수 있음.

The increasing prevalence of obesity is associated with various metabolic diseases such as diabetes, posing significant social and economic burdens to the society. While obesity is a complex disease with multiple factors contributing to its pathophysiology, altered glucose and lipid metabolism is evident in obese patients as well as in animal models. Abnormal metabolic regulation often leads to development of insulin resistance, a hallmark of obesity-induced type 2 diabetes. In this review, we provide a brief overview of altered lipid metabolism manifested in the obese state. In addition, two representative animal models, Mus musculus and Drosophila melanogaster, are presented with experimental approaches adopted for generation and utilization of these models. More specifically, Drosophila has been widely used for studying the core physiological phenomena across phyla for decades, mostly due to the ease of handling and sophisticated genetic manipulations with conserved cell signaling pathways of reduced redundancy. Considering a significant degree of homology in Drosophila for human disease-associated genes, it poses as a versatile in vivo platform to study the pathophysiology of various human diseases. With core metabolic pathways governing energy homeostasis generally conserved, Drosophila can be used as a model for studying molecular mechanisms underlying disease phenotypes manifested in obese and diabetic patients. In this review, we discuss representative Drosophila studies that investigated the effects of dysregulated core signaling pathways on metabolic signatures of obese animals.