Nitrate reductase activity of bacteria in saliva of term and preterm infants
Nitrate reductase activity of bacteria in saliva of term and preterm infants
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DOI：
10.1016/j.niox.2012.07.004
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发表时间：
2012-12-01
影响因子：
3.9
通讯作者：
Blood, Arlin B.
中科院分区：
文献类型：
--
作者：
Kanady, Jesica A.;Aruni, A. Wilson;Blood, Arlin B.
成人的唾液腺将血浆中的硝酸盐浓缩到唾液中，并在唾液中被细菌硝酸还原酶转化为亚硝酸盐。亚硝酸盐可以对成人胃肠道和心血管生理发挥有益作用。当亚硝酸盐被吞下时，其中一些会在胃中转化为一氧化氮（NO），然后可能对胃肠道和全身发挥保护作用。目前尚未确定新生儿何时获得口腔硝酸盐还原菌，或者抗菌治疗或早产对硝酸盐转化为亚硝酸盐的细菌加工有何影响。我们测量了成人以及早产儿和足月婴儿在生命最初几周唾液中的硝酸盐和亚硝酸盐水平。我们还测量了婴儿和成人唾液中的口腔细菌还原酶活性，并表征了存在的硝酸盐还原菌的种类。婴儿中硝酸盐到亚硝酸盐的口腔细菌转化率要么无法检测到，要么显着低于成人的转化率。尽管存在口腔硝酸盐还原细菌，如溶齿放线菌、非典型韦荣球菌和粘液罗氏菌，但在出生后最初两周内，没有发现可测量的还原酶活性。我们得出的结论是，由于缺乏口腔细菌硝酸还原酶活性，到达婴儿胃肠道的亚硝酸盐相对较少。鉴于硝酸盐-亚硝酸盐-NO轴在成人中的重要性，婴儿口腔硝酸盐还原菌的缺乏可能与新生儿对缺氧应激和胃肠道病变的脆弱性有关。 (C) 2012 Elsevier Inc. 保留所有权利。
The salivary glands of adults concentrate nitrate from plasma into saliva where it is converted to nitrite by bacterial nitrate reductases. Nitrite can play a beneficial role in adult gastrointestinal and cardiovascular physiology. When nitrite is swallowed, some of it is converted to nitric oxide (NO) in the stomach and may then exert protective effects in the gastrointestinal tract and throughout the body. It has yet to be determined either when newborn infants acquire oral nitrate reducing bacteria or what the effects of antimicrobial therapy or premature birth may be on the bacterial processing of nitrate to nitrite.We measured nitrate and nitrite levels in the saliva of adults and both preterm and term human infants in the early weeks of life. We also measured oral bacterial reductase activity in the saliva of both infants and adults, and characterized the species of nitrate reducing bacteria present. Oral bacterial conversion of nitrate to nitrite in infants was either undetectable or markedly lower than the conversion rates of adults. No measurable reductase activity was found in infants within the first two weeks of life, despite the presence of oral nitrate reducing bacteria such as Actinomyces odontolyticus, Veillonella atypica, and Rothia mucilaginosa. We conclude that relatively little nitrite reaches the infant gastrointestinal tract due to the lack of oral bacterial nitrate reductase activity. Given the importance of the nitrate-nitrite-NO axis in adults, the lack of oral nitrate-reducing bacteria in infants may be relevant to the vulnerability of newborns to hypoxic stress and gastrointestinal tract pathologies. (C) 2012 Elsevier Inc. All rights reserved.