Title

Genus II. Candidatus Xiphinematobacter

Document Type

Chapter

Abstract

Full-grown cells are rod-shaped with rounded ends, 0.7-1.0x 2.1-3.2 µm; however, cells in the J1 (first juvenile) stage of nematode development have a wrinkled, pleomorphic shape.The longer entities usually consist of a mother cell from which a daughter cell is budding, giving rise to serial pairs typical of this bacterial genus. In thin sections cells have two or three membranes consisting of, from inside to outside, a cytoplasmic membrane, an electron-dense outer membrane, and, in many individuals, a vacuolar membrane which is probably derived from the host cell membrane and which often shows discontinuities. No peptidoglycan layer is evident; however, a periplasmichexagonally arrayed monolayer of 10 nm protein units is sometimes present. Gram-stain-negative, nonmotile, and nonsporulating. DNA is often condensed at cell poles. Bacteria live as obligate cytoplasmic symbionts with maternal transmissionin nematodes of the Xiphinema americanum group (Nematoda,Longidoridae), in which they are presumed to induce the lytokous(mother-to-daughter) parthenogenesis.

Disciplines

Bacteriology | Genetics and Genomics | Life Sciences | Microbial Physiology | Microbiology


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