| 释义 |
mesosome|mɛsəʊˈsəʊmə|
Also mesosoma.
[f. mod.L. mesosoma, f. Gr. µέσο-ς middle + σῶµα body.]
1. Zool.
a. In lamellibranchiate molluscs, the middle region of the body which gives rise to the foot.
b. In Arachnids, the middle portion of the animal, between ‘head’ and ‘tail’.
c. The central part of the body of certain other invertebrates.
1877Huxley Anat. Inv. Anim. viii. 475 From the sides of the mesosoma..the branchiae project into the pallial cavity. 1932Borradaile & Potts Invertebrata xv. 450 The lung books are found on segments 3–6 of the mesosoma. 1962D. Nichols Echinoderms xiv. 174 The lophophore itself is borne by the mesosome, and there is a strong partition between this division of the body and the metasome.
2. Bacteriology. A cytoplasmic structure in many bacteria which is principally composed of membranes, probably being formed by invagination of the cell membrane, and may be a site of active respiratory activity and the place of attachment of the bacterial genome.
1960P. C. Fitz-James in Jrnl. Biophysical & Biochem. Cytol. VIII. 508/2 This [sc. ‘dense body’] is probably an unsuitable name. Certainly they are not always electron dense... Since they appear to be attached to the surface membranes of the cell, one should adopt the suggestion of Robertson..for such membrane-attached cytoplasmic structures and use the term ‘mesosomes’. Henceforth in this paper this term will be used. 1968H. Harris Nucleus & Cytoplasm vi. 123 The loss of the ability to form the cell wall appears to be associated with the disappearance from the cytoplasm of the cell of specific membranous structures, known as ‘mesosomes’, which appear to be essential for the formation of the wall. 1974Nature 1 Feb. 303/1 These properties together with the possession of fimbriae and the absence of mesosomes are commonly shared by Gram-negative, but generally absent in Gram-positive bacteria.
The central part of the body of certain other invertebrates. Hence mesosoˈmatic a., pertaining to the mesosoma.
1893Shipley Zool. Invertebr. xx. 391 The seventh appendage, or the first mesosomatic, consists of a semi⁓circular plate-like structure hinged on to the body. |