CHARACTERIZATION AND SITE DESCRIPTION OF SOLEMYA-BOREALIS (BIVALVIA, SOLEMYIDAE), ANOTHER BIVALVE-BACTERIA SYMBIOSIS
CHARACTERIZATION AND SITE DESCRIPTION OF SOLEMYA-BOREALIS (BIVALVIA, SOLEMYIDAE), ANOTHER BIVALVE-BACTERIA SYMBIOSIS
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DOI：
10.1007/bf00346178
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发表时间：
1992-04-01
期刊：
影响因子：
2.4
通讯作者：
CAVANAUGH, CM
中科院分区：
文献类型：
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作者：
CONWAY, NM;HOWES, BL;CAVANAUGH, CM
1989年4月和7月，在马萨诸塞州Buzzards湾的缺氧沉积物中收集了北方索莱玛（Solemya borealis Totten），并检查了共生的化学自养细菌的存在。此外，对同一地点收集的沉积物岩心进行了全年分析，以详细描述北方针叶蝉的栖息地。在这里，我们展示了结构、酶、生化和稳定同位素数据，这些数据表明，北方S. borealis，如相关物种Solemya velum Say和Solemya reidi Bernard，在鳃细菌细胞中含有高浓度的共生化学自养细菌，这些细菌在营养中起着重要作用。透射电镜显示鳃上皮细胞内存在类似革兰氏阴性菌的杆状细胞。北螺旋藻鳃组织无细胞提取物中的核酮糖-1,5-二磷酸羧化酶活性与其他无脊椎-化学自养共生生物中的活性相当。非常负的δ - s -34比值（-32.6到-15.7‰）表明孔隙水硫化物作为共生体的能量和硫源被利用。碳和氮稳定同位素比率极负（δ -c -13 = -32至-34.6份/千，δ - n -15 = -9.7至-8.6份/千），与其他双壳类-化学自养共生相似。高浓度的顺式异丙酸，一种以前在其他无脊椎动物-化学自养共生中发现的脂肪酸，在北方棘鱼鳃的所有主要脂类中都被发现。北圆螺的稳定同位素比率和脂质组成表明，这种双壳类动物的大部分营养需求是由细菌内共生体提供的。北方松子游离氨基酸库中牛磺酸的高水平表明存在不寻常的氨基酸代谢途径，这可能是内共生活性的结果。北针藻主要分布在以粉砂和粘土为主的浅水沉积物中。沉积物中含有高浓度的有机碳和氮，氧气渗透有限，并且厌氧微生物群落的铵和硫化物输入率很高。沉积物C和N稳定同位素比值反映了藻类来源的营养物质对沉积物的输入（δ C-13 = - 20.7 ~ -20.9‰，δ N-15 = +7.7 ~ +20.8‰）。沉积物δ - s -34比值从-18.7到-25.1‰不等，表明存在由细菌异化硫酸盐还原过程产生的硫。
Solemya borealis Totten was collected from anoxic sediments in Buzzards Bay, Massachusetts in April and July 1989 and examined for the presence of symbiotic, chemoautotrophic bacteria. In addition, sediment cores collected at the same site were analyzed throughout the year, to provide a detailed description of the S. borealis habitat. Here we present structural, enzymatic, biochemical, and stable isotope data which suggests that S. borealis, like the related species Solemya velum Say and Solemya reidi Bernard, contains high concentrations of symbiotic chemoautotrophic bacteria in gill bacteriocytes which play a significant role in nutrition. Transmission electron microscopy revealed the presence of rod-shaped cells, which resemble Gram-negative bacteria, within gill epithelial cells. Ribulose-1,5-bisphosphate carboxylase activity in cell-free extracts of S. borealis gill tissue was comparable with that found in other invertebrate-chemoautotroph symbioses. Very negative (delta-S-34 ratios (-32.6 to -15.7 parts per thousand) suggest the utilization of porewater sulfides as both an energy and a sulfur source for the symbionts. Carbon and nitrogen stable isotope ratios were extremely negative (delta-C-13 = -32 to -34.6 parts per thousand, delta-N-15 = -9.7 to -8.6 parts per thousand), similar to those of other bivalve-chemoautotroph symbioses. High concentrations of cis-vaccenic acid, a fatty acid previously found in other invertebrate-chemoautotroph symbioses, were found in all the major lipid classes of the gills of S. borealis. The stable isotope ratios and lipid composition of S. borealis suggest that most of this bivalve's nutritional requirements are supplied by bacterial endosymbionts. High levels of taurine in the free amino acid pool of S. borealis suggest the existence of unusual amino acid metabolic pathways which may be the result of endosymbiont activity. The S. borealis specimens were found in relatively shallow water sediments dominated by silts and clays. The sediments contain high concentrations of organic carbon and nitrogen, exhibit limited oxygen penetration, and have high rates of ammonium and sulfide input from the anaerobic microbial community. Sediment C and N stable isotope ratios reflect the input of algal-derived nutrients to the sediments (delta-C-13 = - 20.7 to -20.9 parts per thousand, delta-N-15 = +7.7 to +20.8 parts per thousand). Sediment delta-S-34 ratios ranged from -18.7 to -25.1 parts per thousand demonstrating the presence of sulfur produced by bacterial dissimilatory sulfate reduction processes.