ABSTRACT
Abstract: Objective: To analyze the transcription pattern of neuropeptides in the ontogeny of a malaria vector, the mosquito Anopheles albimanus. Materials and methods: The transcription pattern of Crustacean CardioActive peptide (CCAP), corazonin, Ecdysis Triggering Hormone (ETH), allatostatin-A, orcokinin, Insulin Like Peptide 2 (ILP2), Insulin Like Peptide 5 (ILP5) and bursicon was evaluated using qPCR on larvae (1st - 4th instar), pupae and adult mosquitoes. Results: Unlike in other insects, transcripts of CCAP (70.8%), ETH (60.2%) and corazonin (76.5%) were expressed in 4th instar larvae, probably because these three neuropeptides are associated with the beginning of ecdysis. The neuropeptide ILP2 showed higher transcription levels in other stages and orcokinin decreased during the development of the mosquito. Conclusion: The CCAP, corazonin and ETH neuropeptides are potential targets for the design of control strategies aimed at disrupting An. albiamnus larval development.
Resumen: Objetivo: Describir la expresión de neuropéptidos durante la ontogenia del mosquito vector de la malaria Anopheles albimanus. Material y métodos: Se midió la expresión de CCAP, corazonina, ETH, allatostatina, orcokinina, ILP2, ILP5 y bursicon en larvas de primer (2mm), segundo (4mm), tercer (5mm) y cuarto (6mm) estadio, pupas y mosquitos adultos, mediante qPCR. Resultados. A diferencia de otros insectos en donde, CCAP, corazonina y ETH se expresan principalmente en estadios pupales, en An. albimanus se expresaron mayoritariamente en larvas de cuarto estadio, CCAP tuvo 70.8% de expresión relativa, corazonina 76.5% y ETH 60.2%. ILP2 fue el neuropéptido que más se expresó en el primer, segundo y tercer estadio y orcokinina disminuyó durante el desarrollo del mosquito. Conclusión. Los péptidos estudiados se expresaron en todos los estadios de desarrollo del mosquito. Sin embargo, su expresión varió en cada uno de ellos. Los neuropéptidos CCAP, corazonina y ETH, que son esenciales para la transformación de lavas a pupas, pueden ser blancos potenciales para el diseño de estrategias de control dirigidas a interrumpir el desarrollo larvario de An. albimanus.
Subject(s)
Animals , Neuropeptides/biosynthesis , Molting/genetics , Insect Proteins/biosynthesis , Anopheles/genetics , Transcription, Genetic , Neuropeptides/genetics , Gene Expression Regulation, Developmental , Insect Proteins/genetics , Real-Time Polymerase Chain Reaction , Larva , Malaria , Anopheles/growth & developmentABSTRACT
Last instar larvae of S. mauritia treated topically on day 0, day 1, day 2 and day 3 with a daily (dose of 25 microg juvenile hormone analogue (JHA) moulted into supernumerary larvae. The imaginal discs of the supernumerary larvae especially those of mouthparts and thoracic appendages showed pupal characteristics. However the wing discs, which showed only partial differentiation, were uneverted and highly tanned. In an effort to provide an explanation to this anomaly the RNA, DNA and protein profile in the wing discs of supernumerary larvae were studied. Quantitative analysis of DNA, RNA and protein showed a considerable increase in the amount of DNA and protein and a decline in RNA level. SDS-PAGE analysis of wing disc proteins of JHA treated larvae showed a reduction in the expression of many major proteins that were predominant in the wing discs of control larvae. The results suggest that JHA induced inactivation of genes involved in the synthesis of proteins needed for evagination process may be responsible for the formation of uneverted, partially differentiated pupal wing discs in supernumerary larvae.
Subject(s)
Animals , DNA/biosynthesis , Fatty Acids, Unsaturated/pharmacology , Insect Proteins/biosynthesis , Juvenile Hormones/pharmacology , Macromolecular Substances , RNA/biosynthesis , Spodoptera/drug effects , /drug effectsABSTRACT
In silkworm, prothoracicotropic hormone (PTTH), directly or indirectly controls silk production and spinning activity along with juvenile hormone (JH). An effort was made to exploit the potential of PTTH by indirectly activating silk gland for increasing silk productivity using short chain synthetic analogues of PTTH. The analogy in action was also established using PTTH extracted from the silkmoth. Different doses of 42 synthetic PTTH analogues, viz., 2.5, 5, 10 and 20ppm and 3.3 mg/ml of PTTH extracted from silkmoth heads were administered orally to V instar silkworm larvae (Race:KAxNB4D2 and PMxNB4D2) at 0-144 hr at an interval of 24 hr. The analysed data showed an improvement of about 14 - 23% in KA x NB4D2 and about 10-14% in PMxNB4D2 in respect of cocoon shell weight on administration of some of the synthetic PTTH analogues. The PTTH extracted from the adult brain also showed similar effect. The structural analogy of synthetic PTTHs (which improved the shell weight) with original PTTH and its probable mode of action in silkworm are discussed.