PH–077 Alglerde Ubiquitin-Proteazom Yolağı PH–078 A

PH–077
Alglerde Ubiquitin-Proteazom Yolağı
Ayşe Özkan, Atakan Sukatar
Ege Üniversitesi Fen Bilimleri Enstitüsü Hidrobiyoloji Anabilim Dalı
[email protected]
Ubiquitin, yaklaşık 8,5 kDa ağırlığında 76 amino asitten oluşan bütün ökaryotik hücrelerde bulunan
ısıya dayanıklı monomerik bir proteindir. Hatalı proteinlere kovalent olarak bağlanarak ATP bağımlı
proteolitik degredasyonu gerçekleştiren ubiquitin, bunu proteazomlarda gerçekleştirmektedir.
Proteazom ise büyük (26S), multikatalitik proteazlar içeren poliubiquitinlenmiş proteinleri küçük
peptitlere ayıran yapıdır. Ubiquitin, proteazomlara degrede olmak üzere gönderilen proteinlerin bir
etiketi olarak görev yapmaktadır. Ubiquitinin keşfiyle ve buna bağlı olarak yüksek oranda korunmuş
olduğunun anlaşılmasıyla moleküler biyoloji ve genetik çalışmaları bunun üzerine yoğunlaşmış,
ayrıca evrimsel çalışmalarda bu protein baz alınmaya başlanmıştır. Burada da alglerde ubiquitin ve
proteazom yolunda yapılan araştırmalara yer verilecektir.
Anahtar Kelimeler: Ubiquitin, proteazom, alg
PH–078
A Comparative Evaluation of Membrane-Damaging/Protective
Effects of Essential Oil from Origanum Majorana and Linalool
Aysun Özkan, Ayşe Erdoğan
Akdeniz Üniversitesi Fen Fakültesi Biyoloji Bölümü, Antalya, [email protected]
Objectives: The aim of our work was to compare cytotoxic and membrane-damaging effects of
Origanum Majorana (O. Majorana) L. essential oil and its component linalool on Hep G2 and to
investigate their possible protective (antioxidant) effects against H2O2 induced membrane damage.
Materials and Methods: O. majorana L. was collected from Mahmutseydi Village, Alanya (730
m) in Turkey. The dried aerial parts of plants (100 gr) collected were submitted to water distillation
for 3 h using a Clevenger-type. The composition of the volatile constituents was established by GC
and GC/MS. Radical-scavenging activity of the essential oil from aerial parts of O. majorana was
evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay. The potential of the essential
oil to inhibit lipid peroxidation was evaluated using the b-carotene/linoleic acid bleaching test.
Cytotoxicity of the essential oil and linalool was assayed by CellTiter-Blue® Cell Viability Assay.
Malondialdehyde level in Hep G2 cells was measured for membrane damages.
Results: Five components were identified in the essential oil. Its two major components are
carvacrol (52.50%) and linalool (45.4%). The essential oil was able to reduce the stable free radical
DPPH with an EC50 of 170 μg/mL. Inhibition value of linoleic acid oxidation was calculated as 40%
for the oil. Hep G2 cells were incubated with essential oil and linalool different incubation time.
After 24, 48 and 72 incubation periods, IC50 values were calculated respectively, for essential oil
100, 80 and 63 μg/mL and for linalool 81.5, 72.7 and 64.7 μg/mL. Cell viability of Hep G2 cells
1386
21. Ulusal Biyoloji Kongresi, 03–07 Eylül 2012, Ege Üniversitesi, İzmir, Türkiye
http://www.ubk2012.ege.edu.tr

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