Expression of form I and form II Rubisco in chemoautotrophic symbioses: Implications for the interpretation of stable carbon isotope values
Expression of form I and form II Rubisco in chemoautotrophic symbioses: Implications for the interpretation of stable carbon isotope values
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化能自养共生中 I 型和 II 型 Rubisco 的表达：对稳定碳同位素值解释的影响
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
C. Cavanaugh
中科院分区：
文献类型：
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作者：
Jonathan J. Robinson;C. Cavanaugh
无脊椎动物-化学自养共生，其中细菌伴侣为其宿主提供自养固定碳的内部来源，根据先前报道的稳定碳同位素比率分为两大类：61°C = -27至-35%~1的（称为- 300 / 0组）和V3C = -9至- 160 / 0的（称为- 11%~组）。-31X&群的613C值与自由生活的趋化自养细菌相似，表明共生体在双壳类动物的营养中起作用；目前对- 11 ?的613C值没有令人满意的解释。&组。免疫和酶抑制数据表明，在- 11%组的代表中表达的CO，固定酶是II型核酮糖- 1,5-二磷酸羧化酶/加氧酶（Rubisco），而在- 30%共生中表达的是I型Rubisco。先前报道的体外del。纯化Rubisco的终止表明，来自自由生活细菌的形式II酶对CO的kinletic同位素效应比形式i小。因此，在完整的- 1 /00共生体中观察到的富含13c的稳定碳同位素特征似乎至少部分是由于酶的这种减弱的区别。硫氧化化自养细菌与海洋无脊椎动物之间的共生关系是生活在化学还原和氧化环境界面上的生物的重要营养适应（Fisher 1990; Childress and Fisher 1992; Cavanaugh 1994）。最初发现于巨型热液喷口vestimentiferan Riftia pachyptila (Cavanaugh et al. 1981; Felbeck 1981)，这些共生体现在已被描述为五个门（见（Fisher 1990; Cavanaugh 1994）），来自各种海洋栖息地，如热液喷口、高盐冷渗漏、构造俯冲带和减少沉积物。细菌伴侣可以作为细胞内、细胞外或表观共生体出现，据推测，它们通过化学合成为宿主动物提供固定有机碳的来源。虽然共生体尚未培养，但生理学、超微结构和酶学数据支持这一假设。一些最令人信服的证据包括核酮糖- 1,5 -二磷酸羧化酶/加氧酶（Rubisco）活性与特定宿主组织中革兰氏阴性菌的存在共同出现（Cavanaugh 1994）。Rubisco在Calvin-Benson循环中催化初始羧基化，仅在自养生物中发现（Tabita 1988）。因此，为宿主动物提供了来源
Invertebrate-chemoautotroph symbioses, in which the bacterial partner provides an internal source of autotrophically fixed carbon for its host, fall into two main groups based on previously reported stable carbon isotope ratios: those with 6l”C = -27 to -35%~1 (referred to as the - 3Oo/oo group) and those with V3C = -9 to - 16o/oo (referred to as the - 11%~ group). The 613C values of the -31X& group resemble those of free-living chemoautotrophic bacteria, suggesting the role of the symbionts in the nutrition of the bivalves; there is presently no satisfactory explanation for the 613C values of the - 1 1 ?& group. Immunological and enzyme inhibition data are presented demonstrating that the CO,-fixing enzyme expressed in representatives of the - 11% group is a form II ribulose- 1,5-bisphosphate carboxylase/oxygenase (Rubisco), while a form I Rubisco is expressed in the - 30% symbioses. Previously reported in vitro del.erminations on purified Rubisco show that the form II enzyme from free-living bacteria has a smaller kinletic isotope effect with respect to CO, than does form I. Thus, the 13C-enriched stable carbon isotope signature observed in the intact - 1 lo/00 symbioses appears to be at least partially due to this diminished enzymatic discrimination. Symbioses between sulfur-oxidizing chemoautotrophic bacteria and marine invertebrates are known to be important trophic adaptations for organisms living at the interface between chemically reducing and oxidizing environments (Fisher 1990; Childress and Fisher 1992; Cavanaugh 1994). Initially discovered in the giant hydrothermal vent vestimentiferan Riftia pachyptila (Cavanaugh et al. 198 1; Felbeck 198 l), these symbioses have now been described in five phyla (see (Fisher 1990; Cavanaugh 1994)) from marine habitats as varied as hydrothermal vents, hypersaline cold seeps, tectonic subduction zones, and reducing sediments. The bacterial partners, which can occur as intracellular, extracellular, or epibiotic symbionts, are hypothesized to provide the host animal with a source of organic carbon fixed via chemosynthesis. Although the symbionts have not yet been cultured, physiological, ultrastructural, and enzymatic data support this hypothesis. Some of the most compelling evidence includes the co-occurence of ribulose- 1,5 -bisphosphate carboxylase/oxygenase (Rubisco) activity with the presence of gram-negative bacteria in specific host tissues (Cavanaugh 1994). Rubisco catalyzes the initial carboxylation in the Calvin-Benson cycle and is found only in autotrophic organisms (Tabita 1988). The host animal is therefore provided with a source of
影响因子：
56.9
作者：
MORSE, D;SALOIS, P;HASTINGS, JW
通讯作者：
HASTINGS, JW