海洋藻類萃取液對海洋弧菌的抗菌活性

Antibiotic activity of marine algae extracts against marine vibrios

蔡宇軒(Yu-Hsuan Tsai)

指導教授 ： 黃 穰

國立臺灣大學/理學院/海洋研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.10665

摘要

近來消費意識抬頭，水產品是否新鮮與安全，成為消費者關注的重點。海洋水產品的污染又以細菌為主要來源。因此有越來越多研究專注於尋找新的海洋抗菌物質。前人研究證實許多海藻具有顯著的抗菌效果。故本論文以海洋大型及微細藻類為材料，分析其對數種海洋病源菌抑制生長的能力，以評估未來的應用潛力。
本實驗分為三部份，第一部份檢測及篩選海洋藻類，包括 14 種大型藻類與 11 種微細藻類的抗菌活性，測試其對不同菌種的抑制效果。大型藻類自野外採集，微藻則於實驗室培養經冷凍乾燥，研磨及破胞後，以磷酸鹽緩衝液（PBS）或乙醇萃取，測試細菌的生長情形。實驗結果顯示，檢測的大型藻類的 PBS 萃取液普遍有顯著抗菌效果，微細藻類則無。又以 30%、60% 及 80%乙醇萃取，其結果顯示不論大型藻類或微細藻類 ，皆以 80%乙醇萃取液的抑制效果最好。第二部份為探討微藻在不同培養條件與抗生物質生成的關聯性。分析結果顯示，擬球藻 ( Nannochloropsis oculata )在不同光度與營養條件時，其萃取物在抑菌效果上明顯不同。在高光照強度以及氮、磷比比值過低的環境下，擬球藻抗菌活性大幅下降，顯示藻類的生長條件與抗菌活性有高度相關性。最後一部份嘗試分劃及純化抗菌物質。利用硫酸銨沉澱、膠體層析管柱分劃及分離細基龍鬚菜( Gracilaria tenuistipitata ) 的PBS萃取液。結果顯示該海藻的主要抗菌成分不只是蛋白質，尚有其他成分， 須待進一步的純化與確認。本論文研究結果顯示海洋藻類對細菌生長普遍具有抑制的現象，惟其活性因種類及菌株而異。

關鍵字

抗菌活性 ； 大型海藻 ； 微藻 ； 擬球藻 ； 萃取液

並列摘要

Safety and freshness of aquatic products are important for consumers, and bacteria are the main resources of infection of aquatic products. Previous studies indicated that many marine algae could inhibit growth and reproduction of pathogenic bacterium. In this study, we extracted substances from marine microalgae and seaweeds to examine their antibiotic activity against marine vibrios.
There are three parts of the experiment. The first is to assay and screen for antibacterial activity from 25 species of marine algae, including 14 species of seaweeds and 11 species of marine microalgae. Seaweeds were collected from seashores of Taiwan and microalgae were isolated and cultured in the laboratory. Algal materials were freezing-dried, ground generally and extracted with phosphate buffer saline (PBS) and ethanol solution. The results showed that PBS extracts of seaweeds had remarkable inhibitory activity towards the bacteria used, but marine microalgae didn’t. To find out the most appropriate method of extraction, we furthur treated algal materials with 30%, 60%, and 80% ethanol solutions for extraction. The results showed that 80% ethanolic extracts presented the best antibacterial activity for microalgae and seaweeds.
The second part is to assay the antibacterial activity of the chrysophyte Nannochloropsis oculata which was cultured under different light intensities and nutrient conditions. The results showed that antibacterial activity of N. oculata decreased notably as the alga was placed under higher light intensity or provided with less N/P ratio of the medium.
The last part is trying to isolate and purify antibacterial compounds of proteinaceous substances from the red algae Gracilaria tenuistipitata, which were using gel filtration column chromatography. The results showed that the chromatography produced three peaks, two of which were active in inhibition towards Vibrio pelagius growth. However, antibacterial substances and their biochemical characteristics of the alga needs further study.

並列關鍵字

antibacterial activity ； seaweeds ； micro-algae ； Nannochloropsis oculata ； extracts

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