Evans D G, Lampert H C, Nakano H, Eaton K A, Burnens A P, Bronsdon M A, Evans D J
Department of Medicine, Baylor College of Medicine, Veterans Affairs Medical Center, Houston, TX 77030, USA.
Gene. 1995 Sep 22;163(1):97-102. doi: 10.1016/0378-1119(95)00404-t.
Gastric and non-gastric species of Helicobacter were examined for the presence of the adhesin-encoding gene, hpaA, from the human-associated gastric Helicobacter H. pylori (Hp), and for adhesin subunit protein HpaA. Amplification of a 375-bp internal DNA fragment of hpaA by PCR demonstrated the presence of the gene in Hp and in two closely related gastric Helicobacters, H. nemestrinae (Hn) and H. acinonyx (Hx), but not in the more distantly related H. felis (Hf) and H. mustelae (Hm). The non-gastric Helicobacters, H. canis (Hc), H. muridarum (Hr), H. fennelliae (He) and H. cinaedi (Hi), were all negative for hpaA. An immunoblot assay of water extracts with adhesin-specific antibody confirmed these results. The deduced amino acid (aa) sequences of Hp HpaA and Hn adhesin A (hereafter termed HnaA) are very similar, having identical receptor-binding motifs (rbm); also, the hemagglutination (HA) properties of Hn and Hp cells were indistinguishable. In contrast, the rbm of Hx adhesin A (hereafter termed HxaA), compared to that of Hp, contained a non-conservative aa substitution (Ile to Thr); also, there was variance in five consecutive aa from 10 to 14 residues upstream from the rbm. We conclude that these aa substitutions in HxaA are probably responsible for the difference in receptor recognition of this adhesin, as evidenced by the resistance of Hx HA to inhibition with N-acetylneuraminyl-alpha(2,3)-lactose. These results are consistent with the biological similarity between the natural host(s) of Hp and Hn; i.e., human and non-human primates, and the dissimilarity between these hosts and the feline host, the cheetah.
对幽门螺杆菌的胃内和非胃内菌株进行检测，以确定其是否存在来自人类相关胃内幽门螺杆菌（Hp）的黏附素编码基因hpaA以及黏附素亚基蛋白HpaA。通过聚合酶链反应（PCR）扩增hpaA的一个375碱基对的内部DNA片段，结果表明该基因存在于Hp以及两种密切相关的胃内幽门螺杆菌——恒河猴幽门螺杆菌（Hn）和猎豹幽门螺杆菌（Hx）中，但不存在于亲缘关系较远的猫幽门螺杆菌（Hf）和鼬獾幽门螺杆菌（Hm）中。非胃内幽门螺杆菌——犬幽门螺杆菌（Hc）、鼠幽门螺杆菌（Hr）、芬内尔幽门螺杆菌（He）和西奈幽门螺杆菌（Hi），hpaA检测均为阴性。用黏附素特异性抗体对水提取物进行免疫印迹分析证实了这些结果。Hp HpaA和Hn黏附素A（以下称为HnaA）的推导氨基酸（aa）序列非常相似，具有相同的受体结合基序（rbm）；此外，Hn和Hp细胞的血凝（HA）特性无法区分。相比之下，Hx黏附素A（以下称为HxaA）的rbm与Hp相比，包含一个非保守的氨基酸取代（异亮氨酸变为苏氨酸）；而且，在rbm上游10至14个残基处的五个连续氨基酸存在差异。我们得出结论，HxaA中的这些氨基酸取代可能是该黏附素受体识别差异的原因，Hx HA对N-乙酰神经氨酸-α(2,3)-乳糖抑制具有抗性就证明了这一点。这些结果与Hp和Hn天然宿主（即人类和非人类灵长类动物）之间的生物学相似性以及这些宿主与猫科宿主猎豹之间的差异一致。
