Cell lysis and release of particulate polysaccharides in extensive marine mucilage assessed by lipid biomarkers and molecular probes
Cell lysis and release of particulate polysaccharides in extensive marine mucilage assessed by lipid biomarkers and molecular probes
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DOI：
10.3354/meps153045
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发表时间：
1997-01-01
影响因子：
2.5
通讯作者：
Malej, A
中科院分区：
文献类型：
--
作者：
Baldi, F;Minacci, A;Malej, A
在1991年7月亚得里亚海北部发生的大规模黏液事件中，用不同的方法固定了大骨料样品：用甲醛、深度冷冻和冻干。常规显微镜（光镜和荧光显微镜）显示不同的自养物种嵌入胶状基质。蓝藻和异养细菌也被鉴定出来。扫描共聚焦激光显微镜（SCLM）和荧光分子探针（凝集素concanavalin A和UEA-I）显示基质中破裂细胞的包膜中有游离细胞质和颗粒多糖渗出。通过分子探针phalloidin染色观察到无细胞质的细胞骨架，支持了广泛的细胞裂解。高浓度的甘油三酯（占总脂质的30%）和游离脂肪酸（22%）以及极低浓度的磷脂（2%）也表明在冻干材料中细胞大量降解。黏液观察结果与在高营养条件下使用相同技术生长的天然浮游生物群落的黏液观察结果进行了比较。在原位富集实验中观察到游离多糖以球状絮体（海洋雪）的形式存在，在自养生物中观察到胞内多糖作为碳储存材料存在。在藻华期间进行的1个月对照实验中，没有观察到任何表明细胞强烈生物降解的线状、细丝状、层状、细胞裂解或脂类。
During the massive mucilage event in the northern Adriatic Sea in July 1991 samples of macroaggregate were fixed in different ways: with formaldehyde, deep frozen and freeze-dried. Conventional microscopy (light and epifluorescence) revealed different autotrophic species embedded in gelatinous matrix. Cyanobacteria and heterotrophic bacteria were also identified. Scanning confocal laser microscopy (SCLM) and fluorescent molecular probes (the lectins concanavalin A and UEA-I) showed wall-free cytoplasm and particulate polysaccharides leaking from the envelopes of broken cells in the matrix. The extensive cell lysis was supported by the observation of cytoplasm-free cytoskeletons, stained by the molecular probe phalloidin. High concentrations of triglycerides (30% of total lipids) and free fatty acids (22%) along with very low concentrations of phospholipids (2%) also indicated massive cell degradation in freeze-dried material. The mucilage observations were compared with those of a natural plankton community grown under high nutrient conditions using the same techniques. Free polysaccharides were observed as globular flocs (marine snow) during in situ enrichment experiments and intracellular polysaccharides as carbon storage materials in autotrophic organisms. No strings, filaments, layers, cell lysis or lipid classes indicating strong cell biodeterioration were observed in a 1 mo controlled experiment during an algal bloom.