Histološka in ultrastrukturna zgradba srednjega črevesa koloradskega hrošča (Leptinotarsa decemlineata) : magistrsko delo

Jenko, Katja (avtor), Žnidaršič, Nada (mentor), Bogataj, Urban (komentor)

Koloradski hrošč (Leptinotarsa decemlineata) ogroža pridelavo poljščin, zlasti krompirja. Namen raziskave je bil podrobno opisati anatomske, histološke in ultrastrukturne značilnosti srednjega črevesa ter raziskati lokacijo in zgradbo matičnih celic, ki služijo obnavljanju epitela in so potencialna tarča ksenobiotikov v hrani. Vzorce smo kemično fiksirali, vklopili v smolo ter pripravili za analizo s svetlobno in presevno elektronsko mikroskopijo ter za tridimenzionalno rekonstrukcijo zgradbe črevesne kripte. Pokazali smo, da je posteriorno srednje črevo odraslih hroščev iz enoslojnega epitela, ki ga sestavlja več vrst celic, vključno z enterociti in nediferenciranimi celicami. Enterociti imajo številne mikrovile, mitohondrije in endoplazemski retikulum, kar kaže na intenzivno presnovno in absorpcijsko aktivnost. Na bazalni površini črevesa so sferične izbokline, na prerezih razvidne kot invaginacije epitela, imenovane kripte. Kripte vsebujejo številne nediferencirane matične celice in delno diferencirane celice. Majhne kroglaste matične celice vsebujejo okroglo jedro, ki zavzema večino celičnega volumna. V citoplazmi prevladujejo zrnati endoplazemski retikulum in mitohondriji. Tridimenzionalna rekonstrukcija je razkrila kompleksno organizacijo različno diferenciranih celic v kriptah. Sestavni del naloge je tudi poglavje, v katerem obravnavamo na biološko vsebino vezan didaktični vidik - Pedagoški pomen vizualizacije histoloških struktur pri poučevanju biologije. Rezultati naše raziskave so prva karakterizacija zgradbe kript v srednjem črevesu koloradskega hrošča in prvi opis ultrastrukture matičnih celic v njih. Pomemben doprinos te magistrske naloge k metodologiji za analizo zgradbe žuželk predstavlja 3D rekonstrukcija posamezne kripte v srednjem črevesu na osnovi poltankih rezin. V širšem kontekstu so naši rezultati pomemben prispevek k boljšemu razumevanju celične zgradbe črevesnega epitela koloradskega hrošča in k nadgradnji znanja o črevesnih matičnih celicah ter so potencialno uporabni v razvoju novih strategij za zaščito kmetijskih rastlin pred hrošči.

• Jezik: Slovenski jezik
• Ključne besede: Koloradski hrošč, histologija, kripte, ultrastruktura, srednje črevo, matične celice, mikroskopija
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: PEF - Pedagoška fakulteta
• Kraj izida: Ljubljana
• Založnik: K. Jenko
• Leto izida: 2025
• Št. strani: IX, 48 str.
• PID: 20.500.12556/RUL-175478
• UDK: 595.768(043.2)
• COBISS.SI-ID: 255568131
• Datum objave v RUL: 29.10.2025

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Histological and ultrastructural structure of the midgut of the Colorado Potato Beetle (Leptinotarsa decemlineata)

Izvleček

The Colorado potato beetle (Leptinotarsa decemlineata) threatens crop production, especially potatoes. The aim of the study was to describe in detail the anatomical, histological, and ultrastructural characteristics of the midgut and to investigate the location and structure of stem cells that serve to regenerate the epithelium and are potential targets for xenobiotics in food. The samples were chemically fixed, embedded in resin, prepared for analysis by light and transmission electron microscopy and for three-dimensional reconstruction of the structure of the intestinal crypt. We showed that the posterior midgut of adult beetles consists of a single-layered epithelium composed of several cell types, including enterocytes and undifferentiated cells. Enterocytes have numerous microvilli, mitochondria, and endoplasmic reticulum, indicating intense metabolic and absorptive activity. The basal surface of the intestine has spherical protrusions, visible in cross-sections as invaginations of the epithelium - crypts. The crypts contain numerous undifferentiated stem cells and partially differentiated cells. Small spherical stem cells contain a round nucleus that occupies most of the cell volume. The cytoplasm is dominated by granular endoplasmic reticulum and mitochondria. Three-dimensional reconstruction has revealed the complex organization of stem and partially differentiated cells in crypts. The thesis also includes a chapter discussing the didactic aspect related to this biological content - the pedagogical significance of visualizing histological structures in biology education. The results of our research represent the first characterization of the structure of crypts in the midgut of the Colorado potato beetle and the first description of the ultrastructure of stem cells within them. An important contribution of this master's thesis to the methodology for insect structure analyses is the 3D reconstruction of an individual crypt in the midgut, based on semi-thin sections. In a broader context, our results are an important contribution to a better understanding of the cellular structure of the intestinal epithelium of the Colorado potato beetle and to the advancement of knowledge about intestinal stem cells, in addition, the results are potentially useful in the development of new strategies for protecting agricultural crops from beetles.

• Ključne besede: Colorado potato beetle, crypts, histology, ultrastructure, midgut, microscopy, stem cells