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Figure 5 | Biology Direct

Figure 5

From: Mitochondrial activity in gametes and transmission of viable mtDNA

Figure 5

Mitochondrial inner membrane potential (Δψm) in oocytes (Mitotracker Green FM + Mitotracker Red CMXRos). (A) Female acinus (gonadic unit; dashed oval) containing several oocytes of which one of about 40 μm (arrow), positioned at the periphery of the acinus (acinus wall) and portions of oocytes of higher dimension (asterisks) in the acinus lumen. In the small oocyte the mitochondrial mass appears orange-stained, indicating the presence of a membrane potential (both the color components, Mitotracker Green FM and Mitotracker Red CMXRos, are present). The potential is higher in the biggest oocytes (asterisks), in which the mitochondrial mass is strongly red-stained (Mitotracker Red CMXRos component stronger than the Mitotracker Green FM one). Nuclei of cells around the acinus wall are visible in blue (TO-PRO 3 nuclear dye). (B) Detail of the mitochondrial mass of the small oocyte in (A). Nucleus (N) lightly blue-stained. Mitochondria (m) in orange. (C) Oocyte of about 65 μm in which the mitochondrial mass appears orange-stained, indicating the presence of a membrane potential comparable to that of the 40 μm oocyte in (A, B). The oocyte is starting the pedunculated stage. (D) Detail of the mitochondrial mass of the oocyte in (C). The number of mitochondria appears largely increased in comparison to that of the 40 μm oocyte in (A, B). (E) Two oocytes of about 100 μm at the pedunculated stage shortly before the release into the acinus lumen. The membrane potential is high, as indicated by the strong red staining of the mitochondrial mass (Mitotracker Red CMXRos component stronger than the Mitotracker Green FM one). At the periphery of a close acinus, a small oocyte is visible (arrowhead), showing green-orange staining, indicating the presence of a lower membrane potential in comparison to nearly mature eggs. Nuclei of surrounding cells are blue-stained. Nuclei of oocytes (N) are not always stained since the nuclear labelling is not easily absorbed through the yolk.

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