<p>Kukuruzni plamenca (<em>Ostrinia nubilalis</em>, Hbn.) je vrsta umerenog klimatskog područja&nbsp;<br />koja niske zimske&nbsp; temperature preživljava ulaskom u dijapauzu u stadijumu gusenice.&nbsp;Dijapauza i otpornost na hladnoću (cold hardiness,&nbsp; eng.), kod mnogih insekatskih vrsta često&nbsp;predstavljaju esencijalne, tesno povezane komponente strategije preživljavanja delovanja&nbsp;niske temperature, kao &scaron;to je to slučaj i kod kukuruznog plamenca&nbsp; <em>Ostrinia&nbsp; nubilalis</em>, Hbn. U&nbsp;okviru grupe insekata otpornih na hladnoću, svrstava se u insekte otporne na zamrzavanje&nbsp;(freeze tolerant,&nbsp; eng.) jer su&nbsp; sposobne da prežive ekstracelularno zamrzavanje telesnih&nbsp;tečnosti.</p><p>Iako se o osnovnim strukturnim i metaboličkim de&scaron;avanjima u dijapauzi insekata već dosta&nbsp;zna, jo&scaron; uvek postoje brojne dileme o ovom vidu preživljavanja insekata u nepovoljnim&nbsp;uslovima sredine, posebno sa aspekta izloženosti niskim zimskim temperaturama i&nbsp;mehanizmima krioprotekcije. Zbog toga je&nbsp; cilj ove doktorske disertacije&nbsp; bio&nbsp; da se sa aspekta&nbsp;biofizičkih osobina lipida i sastava masnih kiselina: &nbsp;odrede biofizičke osobine (temperature&nbsp;faznog prelaza) ukupnih lipida nedijapauzirajućih i dijapauzirajućih gusenica tokom dijapauze&nbsp;(početak, sredina i kraj),&nbsp; kao i u kontrolisanim uslovima hlađenja dijapauzirajućih gusenica;&nbsp;zatim da se&nbsp; odredi zastupljenost pojedinih klasa lipida u hemolimfi i masnom telu&nbsp;nedijapauzirajućih i dijapauzirajućih gusenica;&nbsp; da se&nbsp; utvrde promene sastava masnih kiselina&nbsp;strukturne (polarne) i rezervne (nepolarne)&nbsp; frakcije&nbsp; lipida celih gusenica&nbsp; tokom dijapauze i&nbsp;pod uticajem različitih temperatura u eksperimentalnim uslovima; kao i da se&nbsp; odredi tkivna&nbsp;specifičnost, hemolimfe i masnog tela, masnih kiselina ukupnih lipida&nbsp; i&nbsp; biofizičke&nbsp; osobine&nbsp;ukupnih lipida masnog tela nedijapauzirajućih i dijapauzirajućih gusenica tokom dijapauze,&nbsp;kao i u kontrolisanim uslovima hlađenja dijapauzirajućih gusenica.&nbsp;&nbsp;</p><p>U analizi lipida kukuruznog plamenca <em>Ostrinia nubilalis</em>, Hbn. kori&scaron;ćene su sledeće tehnike:&nbsp;tankoslojna hromatografija (TLC) sa skenirajućom denzitometrijom, za razdvajanje i analizu&nbsp;klasa lipida;&nbsp; zatim&nbsp; gasno-masena hromatografija (GC-MS), za analizu masnih kiselina kao i&nbsp;diferencijalna skenirajuća kalorimetrija (DSC&nbsp; &ndash;&nbsp; differential scanning calorimetry,&nbsp; eng.), za&nbsp;termalnu analizu ekstrahovanih lipida.</p><p>Kod&nbsp; gusenica <em>Ostrinia&nbsp; nubilalis</em>&nbsp;sastav&nbsp; masnih kiselina ukupnih lipida analiziranih tkiva i&nbsp;lipidnih frakcija značajno se razlikuje između&nbsp; ova dva fiziolo&scaron;ka stanja, stanja dijapauze i&nbsp;nedijapauze.&nbsp; Dijapauza indukuje značajno povećanje sadržaja mononezasićenih masnih&nbsp;kiselina, pre svega palmitoleinske (16:1n-7) i oleinske masne kiseline (18:1n-9) uz&nbsp;istovremeno smanjenje sadržaja zasićenih i&nbsp; polinezasićenih masnih kiselina, pre svega&nbsp;palmitinske (16:0) i linolne masne kiseline (18:2n-6).&nbsp; Temperature faznog prelaza ukupnih&nbsp;lipida celih gusenica i masnog tela&nbsp; značajno su niže kod dijapauzirajućih gusenica&nbsp; <em>O.&nbsp;nubilalis</em>,&nbsp; usled &nbsp;značajnog povećanja&nbsp; stepena nezasićenosti masnih kiselina u njihovom&nbsp;sastavu. Značajno niže temperature&nbsp; faznog prelaza lipida dijapauzirajućih gusenica&nbsp; <em>O.<br />nubilalis</em>&nbsp; rezultat su povećanja stepena nezasićenosti njihovih masnih kiselina. Možemo&nbsp;zaključiti da su&nbsp; promene u sastavu&nbsp; masnih kiselina lipida indukovane dijapauzom važna&nbsp;komponenta preživljavanja niskih temperatura kod&nbsp; <em>O. nubilalis</em>&nbsp; Hbn. jer se&nbsp; veliki deo lipida&nbsp;održava u tečnom stanju čak i na temperaturama daleko ispod 0&deg;C, &scaron;to je neophodno za&nbsp;održavanje njihove fluidnosti odnosno funkcionalnosti.</p> / <p>European corn borer (<em>Ostrinia nubilalis</em>,&nbsp; Hbn.)&nbsp; inhabiting temperate regions&nbsp; that&nbsp;survive low winter temperatures as a diapausing fifth instar larva.&nbsp; Diapausing larvae are cold&nbsp;hardy and freeze tolerant as they are able to survive the extracellular formation of ice crystals.&nbsp;Winter survival for many insect species living in seasonally cold environments includes a&nbsp;radical remodeling of metabolism. This implies entry into a developmentally arrested,&nbsp;hypometabolic state of winter diapause, which in <em>O. nubilalis</em>&nbsp; and&nbsp; many&nbsp; other&nbsp; insect species&nbsp;of these habitats is closely related to their cold hardiness.</p><p>Although the basic structural and metabolic events consider insect diapause is already known,&nbsp;there are still many doubts about the survival of insects in an unfavorable environment,&nbsp;particularly in terms of&nbsp; exposure to low winter temperatures &nbsp;and mechanisms of&nbsp;cryoprotection. Therefore, the aim of this thesis in terms of biophysical properties of lipids&nbsp;and fatty acid compositions,&nbsp; was to: i) to determine &nbsp;the biophysical properties (phase&nbsp;transition temperatures) of the total lipids of non-diapausing&nbsp; larvae&nbsp; and diapausing larvae&nbsp;during diapause (early diapause, mid diapause and termination of diapause), as well as under&nbsp;controlled cooling conditions during different phases of diapause; ii) to determine the fatty&nbsp;acid compositions of structural (polar) and storage (non-polar)&nbsp; total&nbsp; lipid fractions of non-diapausing&nbsp; larvae&nbsp; and diapausing larvae, as well as under the influence of different&nbsp;<br />temperatures during diapause in the controled experimental conditions; iii)&nbsp; to determine the&nbsp;lipid classes&nbsp; composition of total lipids extracted from the haemolymph and fat body of non-diapausing and diapausing larvae;&nbsp; iiii) to determine&nbsp; the haemolymph and fat body total lipid&nbsp;fatty acid compositions&nbsp; as well as the biophysical properties of the fat body total lipids of&nbsp;non-diapausing larvae&nbsp; and diapausing larvae during diapause as well as in terms of controlled&nbsp;cooling conditions. Thus, our research was focused on the non-diapausing (ND) as well as the&nbsp;diapausing larvae&nbsp; (D) that&nbsp; were exposed to low temperatures during different phases&nbsp; of&nbsp;diapause.</p><p>During analysis of European corn borer&nbsp; <em>O. nubilalis</em>&nbsp; lipids, the following techniques was&nbsp;used: thin&nbsp; layer&nbsp; chromatography (TLC) with scanning densitometry, for the separation and&nbsp;quantification&nbsp; of lipid classes; gas-mass chromatography (GC-MS ) for the&nbsp; analysis of the&nbsp;fatty acid composition&nbsp; of lipids and&nbsp; the differential scanning calorimetry (DSC), for the&nbsp;thermal analysis of the extracted lipids.</p><p>The fatty acid compositions&nbsp; and biophysical properties of lipids differed markedly between&nbsp;non-diapausing and diapausing larvae&nbsp; of&nbsp; <em>O. nubilalis</em>. Diapause was associated with a&nbsp;dramatic increase&nbsp; mainly the proportions of palmitoleic acid (16:1n-7) and oleic acid (18:1n-9), with concurrent reductions in palmitic acid (16:0) and linoleic acid (18:2n-6). The increase&nbsp;in&nbsp; the level of unsaturation of&nbsp; lipids,&nbsp; which caused a marked shift in their phase transitions to&nbsp;lower temperatures,&nbsp; was triggered&nbsp; by diapause rather than low temperatures.&nbsp; Adjustments of&nbsp;fatty acid compositions are likely to be an important component of winter diapause &nbsp;mechaisms, possibly maintaining the fluidity of cell membranes, and the functionality &nbsp;of the&nbsp;organism during lower winter temperatures.&nbsp; We conclude that&nbsp; <em>O. nubilalis &nbsp;</em>undergoes&nbsp;remodeling of fatty acid profiles of lipids as an element of its overwintering physiology which&nbsp;may improve the ability to harden during diapause.</p>

Des substances toxiques générées par les activités portuaires, urbaines et industrielles sont déversées à certains niveaux du milieu marin côtier marocain. Les mollusques peuvent concentrer les polluants et avoir des effets néfastes sur la santé humaine par l’intermédiaire de la chaîne alimentaire. Malgré le renforcement des mesures de sécurité alimentaire, l’implication de la pollution chimique des aliments dans les troubles métaboliques n’est pas à exclure. Pour prédire l’impact des polluants sur l’écosystème aquatique et sur la santé humaine, le développement d’outils de biosurveillance est nécessaire.Nous avons quantifié les métaux lourds (Cd, Cr et Pb) chez les moules (Mytilus galloprovincialis) issues de la côte atlantique marocaine (site industriel Jorf Lasfar (JL) et site touristique d’Oualidia (OL)) en raison de la proximité d’une plateforme d’extraction de phosphate puis caractérisé leurs profils lipidiques (acides gras, cholestérol, oxystérols, phytostérols et phospholipides). Les extraits lipidiques totaux de moules ont été testés in vivo sur des rats pour déterminer leurs effets sur les paramètres biochimiques plasmatiques et in vitro sur une lignée de cellules β pancréatiques murine (MIN-6) en conditions normo et hyperglycémique. Les effets des extraits de moules JL et OL ont été comparés par rapport à ceux de moules d’origine espagnole (ES) destinées à la consommation en France.Les métaux lourds dans les moules JL dépassent les normes internationales. Les concentrations métalliques dans tous les extraits lipidiques sont à l’état de trace. Les moules JL et OL sont moins riches en acides gras insaturés, plus riches en oxystérols et en phospholipides par rapport aux moules ES, suggérant un stress environnemental. Les extraits lipidiques des moules JL et OL administrés à des rats, ont provoqué une perturbation des paramètres plasmatiques, notamment des taux de glucose, créatinine, triglycérides et transaminases avec une augmentation de cholestérol-HDL. In vitro seuls les extraits lipidiques JL et OL induisent la mort des cellules MIN-6 par un processus non apoptotique. Ce processus est associé à une dépolarisation mitochondriale, une déstabilisation lysosomale et une augmentation de la perméabilité de la membrane cytoplasmique, paramètres mesurés par cytométrie en flux dans une démarche cytomique. Ils provoquent aussi une surproduction de H2O2, une augmentation d’activité catalase, une diminution du glutathion réduit, une peroxydation lipidique et une forte stimulation de la sécrétion d’insuline avec un effet plus marqués en présence des extraits lipidiques JL.Globalement, les lipides de moules JL induisent des effets néfastes in vivo et in vitro par rapport à ceux provenant de OL et ES. Une étude épidémiologique à large échelle dans le contexte des maladies métaboliques pourrait être pertinente chez les populations consommatrices de ces moules. / Toxic substances generated by various human activities are spilled on different area of the Moroccan coast. Shellfishes can concentrate pollutants and have some adverse effects on human health through the food chain. Despite the strengthening of food safety rules, the involvement of chemical pollution of food on metabolic disorders is not known. To predict the impact of pollutants on the aquatic ecosystem and human health, the development of appropriate biomonitoring tools is required.We quantified heavy metals (Cd, Cr and Pb) in mussels (Mytilus galloprovincialis) from two sites of Moroccan Atlantic coast (industrial site Jorf Lasfar (JL) and touristic site Oualidia (OL)) due to the proximity of a phosphate extraction platform, and further characterized their lipid profiles (fatty acids, cholesterol, oxysterols, phospholipids and phytosterols). Total lipid extracts of mussels were tested in vivo in rats to determine their effects on biochemical plasmatic parameters and in vitro on a β pancreatic murine cell line (MIN-6) in normo-and hyperglycemic conditions. The effects of JL and OL mussel extracts were compared to mussels from Spain (ES) used for human consumption in France. Heavy metals in JL mussels exceed international standard level. Metal concentrations in all lipid extracts are present in small quantity. JL and OL mussels are less enriched in unsaturated fatty acids, oxysterols and contain higher levels of phospholipids than ES mussels, suggesting an environmental stress. The lipid extracts of JL and OL mussels administered to rats induce a disruption of plasmatic parameters (glucose, creatinine, transaminases and triglycerides) with an increase of HDL-cholesterol. In vitro, only JL and OL lipid extracts induce MIN-6 cell death by a non-apoptotic process. This process is associated with mitochondrial depolarization, lysosomal destabilization and an increase of the cytoplasmic membrane permeability, parameters measured by flow cytométrie in a cytomic context. They also induce an overproduction of H2O2, an increase of catalase activity, a decrease of reduced glutathion, lipid peroxidation and a strong stimulation of insulin secretion with a more marked effect in presence of JL lipid extracts.Overall, JL mussel lipids induce various side effects in vivo and in vitro, which are more pronounced that those observed with OL and ES. A large-scale epidemiological study could be of interest to confirm the potential side effects of these mussels to favor metabolic disorders.