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PubMed2005

Oogenesis in the leech Glossiphonia heteroclita (Annelida, Hirudinea, Glossiphonidae). I. Ovary structure and previtellogenic growth of oocytes.

Glossiphonia heteroclita has paired ovaries whose shape and dimensions change as oogenesis proceeds: during early previtellogenesis they are small and club-shaped, whereas during vitellogenesis they broaden and elongate considerably. During early oogenesis (previtellogenesis), each ovary is composed of an outer envelope (ovisac) that surrounds the ovary cavity and is filled with hemocoelomic fluid, in which a single and very convoluted ovary cord is bathed. The ovary cord consists of germline cells, including nurse cells and young oocytes surrounded by a layer of elongated follicle cells. Additionally, follicle cells with long cytoplasmic projections occur inside the ovary cord, where they separate germ cells from each other. The ovary cord contains thousands of nurse cells. Each nurse cell has one intercellular bridge, connecting it to a central anucleate cytoplasmic mass, the cytophore (rachis); it in turn is connected by one intercellular bridge with each growing oocyte. Numerous mitochondria, RER cisternae, ribosomes, and Golgi complexes are transported from the nurse cells, via the intercellular bridge and cytophore, to the growing oocytes. Oogenesis in G. heteroclita is synchronous with all oocytes in the ovary in the same stage of oogenesis. The youngest observed oocytes are slightly larger than nurse cells, and usually occupy the periphery of the ovary cord. As previtellogenesis proceeds, the oocytes gather a vast amount of cell organelles and become more voluminous. As a result, in late previtellogenesis the oocytes gradually protrude into the ovary cavity. Simultaneously with oocyte growth, the follicle cells differentiate into two subpopulations. The morphology of the follicle cells surrounding the nurse cells and penetrating the ovary cord does not change, whereas those enveloping the growing oocytes become more voluminous. Their plasma membrane invaginates deeply, forming numerous broad vesicles that eventually seem to form channels or conducts through which the hemocoelomic fluid can easily access the growing oocytes.

Animals↗
PubMed1995

Morphological, histochemical, and ultrastructural characterization of the salivary glands and proboscises of three species of glossiphoniid leeches (Hirudinea: Rhynchobdellida).

Morphological and ultrastructural features of the salivary glands and proboscises of Placobdella ornata, Placobdella parasitica, and Desserobdella picta were studied by light and electron microscopy. Chemical composition of the salivary cells was investigated using a variety of histochemical techniques. Placobdella ornata and P. parasitica have compact salivary glands with discrete pairs of anterior and posterior glands, while the salivary cells contain one mucous and three proteinaceous secretions. Salivary glands of D. picta are diffusely arranged and contain two mucous and two proteinaceous secretions. A cobalt-lysine forward-filling technique revealed that individual salivary cells consist of a roughly spherical soma and an elongated ductule. The majority of the internal space in a salivary soma is densely packed with spherical secretory granules which displace the cytoplasm to the periphery of the cell. Bundles of individual ductules enter the base of the proboscis on opposite sides and extend anteriorly. The ductules, also packed with secretory granules, are surrounded by microtubules associated with agranular endoplasmic reticulum, and merge with deep invaginations of the proboscis cuticle. The secretory granules are released at the end of these invaginations or pores. Pores were found on the tip, along the body, and on the luminal wall of the proboscises in all three species.

Animals↗
PubMed1986

Successful transfer of "free" microvascular superficial temporal artery flap with no obvious venous drainage and use of leeches for reducing venous congestion: case report.

A case is presented of "free" flap based on the frontal branch of the left superficial temporal artery and its surrounding soft tissues, without any proper vein for anastomosis, successfully transferred for eyebrow reconstruction. One can argue that this flap was a Wolfe graft. It probably was not for two reasons. First, "hairy Wolfe grafts" are always composite grafts with a thickness of 3-4 mm, as the base of the hair follicles lies in the subcutaneous tissue. Second, the edges of the flap were not sutured to the surrounding skin. Therefore, vascularization is unlikely from the surrounding skin and there was constant, definite oozing from the edge of this flap.

Animals↗
PubMed1988

The role of the sexual organs in the generation of postembryonic neurons in the leech Hirudo medicinalis.

In adult Hirudo medicinalis, the segmental ganglia (SG) of the fifth and sixth body segments contain a few hundred more cells than the other segmental ganglia of the body (Macagno, 1980). These ganglia innervate the sex organs and are known as the sex SG. As shown here, these cells are stained by neuron-specific antibodies. Cell counts at several developmental stages reveal that the extra cells are added exclusively to the sex SG, and that this addition occurs gradually and almost entirely postembryonically (embryogenesis ends at 30 days of development). Hence, we refer to them as PE cells. Until 16 days of development, deleting the male genitalia or disconnecting them from the sex ganglia results in a complete absence of the PE cells. From 16 days onward, the generation of the PE cells is independent of the male genitalia. No PE cells appear in non-sex SG that innervate male genitalia transplanted to ectopic locations at 10 days or later, indicating that as early as about 10 days of development sex SG are different from other SG in their ability to acquire PE cells. These data suggest that the PE cells are generated within the sex SG, in a process that is triggered by an interaction with the male genitalia and mediated through the innervation of the organs by these ganglia.

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