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. Author manuscript; available in PMC: 2021 Jun 18.
Published in final edited form as: FASEB J. 2021 May;35(5):e21513. doi: 10.1096/fj.202002799R

FIGURE 1.

FIGURE 1

Early prepubertal human and pig spermatogonia have a similar, distinct mitochondrial ultrastructure. A-F, Infant human testis. A, Seminiferous chord in 9-month-old human testis (TEM, white arrows indicate spermatogonia with unilaterally accumulated mitochondria; scale bar 5 μm). B, Seminiferous chord in 6-month-old human testis (IHC for TOMM-20 (red), UCH-L1 (green), white arrows indicate spermatogonia with unilaterally accumulated mitochondria, scale bar 5 μm). C, Early prepubertal (9-month-old human) spermatogonium (green outline) with unilaterally accumulated mitochondria (white arrow), TEM, scale bar 2 μm. D, Early prepubertal spermatogonium (6-month-old human) (IHC for TOMM-20 (red), UCH-L1 (green), white arrow indicates accumulated mitochondria, scale bar 2 μm). E, Mitochondria in early prepubertal spermatogonium (TEM; 9-month-old human, red arrowhead indicates intermitochondrial cement, scale bar 1 μm). F, Mitochondria in early prepubertal Sertoli cell (9-month-old human, white arrows indicate elongated mitochondria, scale bar 1 μm). G-I, Prepubertal pig testis. G, Seminiferous chord in 1-week-old pig testis (TEM; white arrows indicate early prepubertal spermatogonia, scale bar 3 μm). H, Seminiferous chord in 1-week-old pig testis (IHC for TOMM-20 [red], UCH-L1 [green], white arrows indicate spermatogonia with unilaterally accumulated mitochondria, scale bar 5 μm). I, Early prepubertal (1-week-old pig) spermatogonium (green outline) with unilaterally accumulated mitochondria (white arrow), TEM, scale bar 2 μm. Interrupted line indicates the basement membrane, mitochondria mostly accumulated under a 90° angle towards the basement membrane. J, Early prepubertal spermatogonium (1-week-old pig) (IHC for TOMM-20 [red], UCH-L1 [green], white arrow indicates accumulated mitochondria, scale bar 3 μm). K, Mitochondria in early prepubertal (1-week-old pig) spermatogonium (TEM, red arrowhead indicates intermitochondrial cement, scale bar 100 nm). L, Mitochondria in early prepubertal (1-week-old pig) Sertoli cell (TEM; scale bar 100 nm)