Three dimensional secondary ion mass spectrometry imaging (3D-SIMS) ofAedes aegyptiovarian follicles

Abstract

The mobilization of nutrient reserves into the ovaries of Aedes aegypti mosquitoes after sugar-feeding plays a vital role in the female's reproductive maturation.

Following De Novo Triglyceride Dynamics in Ovaries of Aedes Aegypti Mosquitoes

“…This approach enables direct analysis of nutrient distribution, mobilization and metabolism. 4,23,37,[43][44][45] While the concept is simple, for the analysis of complex biological samples it requires: i) the use of complementary pre-separation techniques to diminish matrix effects and increase the sensitivity of the analysis 27,37,[46][47][48][49][50][51][52][53] and ii) the use of high magnetic elds to achieve ultrahigh mass resolution with short transient duration for compatibility with LC separation (e.g., resolving power greater than m/Dm 50% > 1000000 and mass accuracy better than 1 ppm). 27,36,[41][42][43][46][47][48] More recently, in addition to the use of higher magnetic elds, alternative detection strategies (e.g., hexapolar detection, 3W+) has allowed better sensitivity and shorter analysis time, making more e cient the coupling of LC-FT-ICR MS. 41,46,47,54 1).…”

“…Ovaries were dissected by performing an incision in the thorax, cutting the last abdominal segment and pulling out the ovaries. 27 Triplicates samples of 10 ovaries each were placed in 1.5 mL Eppendorf tubes, and 10 µL of a mix of labeled internal standard were added (EquiSplash Lipidomix, Avanti Polar Lipids, Alabaster, AL). After adding 100 µL of butanol/methanol and 3 µL of butylated hydroxytoluene, samples were homogenized for 10 seconds using polypropylene pestles (Fisher Scienti c, Pittsburgh, PA), and a handheld cordless motor.…”

“…22,23 While TG is the principal lipid produced in the fat body [24][25][26] , most of the lipids found in the hemolymph are in the form of diglycerides (DG). 24,25,27 The transport of lipids among tissues is mediated by Lipophorin (Lp) and the Lipid Transfer Particle (LTP). 16,18,28,29 Previous studies suggested that the ovaries can only synthesize small amounts of lipids 30,31 , therefore the majority of ovarian lipids must be produced elsewhere (e.g., fat body).…”

“…16,18,28,29 Previous studies suggested that the ovaries can only synthesize small amounts of lipids 30,31 , therefore the majority of ovarian lipids must be produced elsewhere (e.g., fat body). 15,16,27,32 While TG reserves can be carried from the larva stage, de novo TG synthesis play undoubtedly a key role in Ae. aegypti oogenesis.…”

Mass spectrometry imaging: An emerging technology for the analysis of metabolites in insects

“…D. melanogaster, as a biological model insect, has been widely used in many perspectives of MSI, such as three-dimensional spatial distribution of neutral lipids on the surface of adults (Kaftan et al, 2014), lipid distribution in the body (Niehoff et al, 2014), lipid structure in brain (Le et al, 2018;Phan, Munem, Ewing, & Fletcher, 2017), lipids of the wing (Marty et al, 2017;Vrkoslav, Muck, Cvačka, & Svatoš, 2010), and phospholipid distribution of the malpighian tubules (E. Yang, Gamberi, & Chaurand, 2019). In addition to D. melanogaster, MSI has also been used to detect and localize phospholipid, phosphatidylcholine, or triacylglyceride composition and distribution in the mosquito (Anopheles stephensi or Aedes aegypti; Castellanos et al, 2019;Khalil, Römpp, Pretzel, Becker, & Spengler, 2015), and phospholipids in locusts (Scistocerca gregaria; Olsen et al, 2015). Compared with other techniques such as LC-MS/ MS, MSI could simultaneously detect the distributions of multiple lipids at different tissues or cells, which contributes to illuminating the importance of lipids at insect energy metabolisms.…”