Bıologıcal actıvıtıes of levan by halomonas sp.
Bibliographic record
Abstract
HALOMONAS sp. ’DEN ÜRETİLEN LEVANIN BİYOLOJİK AKTİVİTELERİ \nLevan birçok bitkide bulunan ve mikroorganizmalarca üretilen fruktan tipi bir biyoaktif polimerdir. Suda çözünen, güçlü bir yapışkan ve film oluşturucu biyopolimer olan levan polisakkariti, düşük viskozite, yağda yüksek çözünürlük, tuzlarla ve surfaktanlarla uyumluluk, sıcak, asidik ve bazik ortamlara dayanıklılık, su ve kimyasalları tutma kapasitesinin yüksekliği ve biyouyumluluk gibi değerli birçok özelliği ile diğer polisakkaritlerden ayrılmaktadır. Levan ve medikal endüstrideki potansiyel uygulama alanlarına olan ilginin giderek artması göz önünde bulundurularak ilk defa bu çalışma ile Halomonas smyrnensis AAD6T tarafından üretilen lineer levanın biyolojik aktiviteleri incelenmiştir. Ilk olarak pankreatik β-hücrelerinde ve yüksek şeker ortamında, CM-H2DCFDA ve kaspaz 3/7 olmak üzere hücre bazlı iki farklı yöntem kullanılarak antioksidan aktivitesi çalışılmıştır. Sonuçlar doğrultusunda yüksek şeker konsantrasyonu şartlarında artan apoptoz değerlerini levanın düşürüp oksidatif stresi azalttığı ve antioksidan aktivitesi gösterdiği bulunmuştur. Aynı zamanda, levan polimeri oksitlenerek farklı oksidasyon derecelerine sahip aldehit grubu içeren türevleri oluşturulmuştur. Bu polimerin ve oksitlenmiş türevlerinin A549 (akciğer kanseri), HepG2/C3A (karaciğer kanseri), AGS (mide kanseri) ve MCF-7 (meme kanseri) gibi farklı kanser hücre hatlarında anti-kanser aktivitesi, sağlıklı fare fibroblast hücrelerinde (L929) sitotoksisitesi ve RAW 264.7 makrofaj tipi hücrelerde ise immün düzenleyici aktivitesi incelenmiştir. Anti-kanser aktivite WST-1 hücre proliferasyonu analizi ile, kaspaz 3/7 aktivitesi ApoTox-Glo üçlü analiz yöntemi ile, immün düzenleyici aktivite ise Griess reaksiyonuna bağlı kolorimetrik yöntem ile değerlendirilmiştir. Sonuçlar doğrultusunda, örneklerin hiç birisi L929 hücrelerinin canlılığını olumsuz etkilememiştir. En yüksek oksidasyon derecesine sahip levan türevi tüm kanser hatlarına karşı en yüksek anti-kanser aktiviteyi göstermiştir. Herhangibir modifikasyona uğramamış levan makrofaj hücrelerine toksik etki göstermeyip NO oluşumunu stimule etmiştir. Sonuçlar levan türevlerinin gelecek vaadeden bir antioksidan, anti-kanser ve immune sistemi düzenleyici ajan olabileceğini öne sürmektedir. Yapılan çalışmalar, levan ve türevlerinin medikal uygulamaları açısından büyük önem taşımaktadır.\nABSTRACT \nBIOLOGICAL ACTIVITIES OF LEVAN BY HALOMONAS sp.\nLevan is a bioactive fructan type polymer found in many plants and produced by many microorganisms. As a water soluble, strongly adhesive and film-forming biopolymer, levan is distinguished from other polysaccharides by its valuable properties like low viscosity, high solubility in oil, compatibility with salts and surfactants, stability to heat, acid, and alkali media, high holding capacity for water and chemicals, and good biocompatibility. Considering the ever increasing interest in levan and its potential applications in medical industry, for the first time with the present study, biological activities of linear levan from Halomonas smyrnensis AAD6T were evaluated. First, antioxidant activity by using two different cell-based methods; CM-H2DCFDA assay and caspase 3/7 assay, was investigated under high glucose condition in pancreatic β-cell line. Levan was found to attenuate oxidative stress that is associated with decreased apoptosis in high glucose condition suggesting the antioxidant role of this polymer. On the other hand, levan was subjected to oxidation, producing the aldehyde derivatives with different degree of substitution. Anti-cancer activity of this polymer and its aldehyde activated derivatives were investigated in different cancer cell lines; such as A549 (human lung adenocarcinoma), HepG2/C3A (human liver hepatocellular carcinoma), AGS (human gastric adenocarcinoma), and MCF-7 (human breast adenocarcinoma), while demonstrating their cytotoxicity in the mouse fibroblast cell line L929 and immunostimulating activity in macrophage cell line RAW 264.7. The WST-1 assay was performed for evaluating anticancer activity of levan samples, ApoTox-Glo triplex assay was performed for detecting caspase 3/7 activity, and colorimetric assay based on the Griess reaction was performed for measuring NO production reletad to immunostimulating activity. As a result, samples didn’t show cytotoxicity in L929 cell line. Oxidized form of levan with the highest oxidation degree showed the highest anticancer activity in all cancer cell lines. Pure levan showed no toxicity on macrophages while it increased production of NO in RAW264.7 cells. The results suggested that levan and its derivatives could be explored as promising antioxidant, anticancer, and immunostimulating agents. These studies hold great importance for the medicinal applications of levan and its chemical derivatives.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.014 | 0.010 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.010 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".