Frogs with denser group-spawning mature later and live longer.

The understanding of the intrinsic and extrinsic causes of longevity variation has deservedly received much attention in evolutionary ecologist. Here we tested the association between longevity and spawning-site groups across 38 species of Chinese anurans. As indicators of group-spawning we used spawning-site group size and spawning-site density, which we measured at 152 spawning sites in the field. We found that both spawning-site density and group size were positively associated with longevity. Male group-spawning (e.g., male spawning-site density and male spawning-site group size) was also positively correlated with longevity. A phylogenetic path analysis further revealed that longevity seems directly associated with spawning-site density and group size, and that the association in part depend on the 'groups-spawning-age at first reproduction' association. Our findings suggest that the increased group-spawning are likely to benefit in declining extrinsic mortality rates and living longer through improving total anti-predator behaviour under predation pressure.

The investigation on the role of mitochondrial fusion protein 1 in the development of myopia.

PURPOSE: The aim of this study is to preliminarily investigate the expression of mitochondrial fusion protein 1 (MFN1) in a lens-induced animal myopia (LIM) model and to explore the relationship between MFN1 and the visual development. MATERIALS AND METHODS: MFN1 gene expression in guinea pigs was examined during the development of minus LIM, 15 tri-colored guinea pigs were obtained, and one eye of each pig was randomly selected and treated with -7.00D lenses. Ocular refraction and axial length were collected before intervention and 1, 2, and 3 weeks after intervention. After the refraction and axial length measurements at 1, 2, and 3 weeks of lens intervention, five guinea pigs were randomly selected. MFN1 expression in the retina of both eyes was tested by immunohistochemistry technique. RESULTS: MFN1-positive cells could be observed in the retina of both eyes. The positive cells in the LIM eyes were staining deeper, and much more positive cells could be observed. Furthermore, MFN1-positive expression could be seen mainly in ganglion cells after 1 week of minus lens intervention, and with time extension, more and more positive cells appeared in the rod-cone cell and bipolar cell layer, and this phenomenon could not be found in the normal control eyes. CONCLUSION: This study suggested that MFN1 might be correlated to the development of myopia.

[Histological effects of unilateral spermatic cord torsion without removal of the ipsilateral necrotic testis on the contralateral testis in rats].

OBJECTIVE: To investigate the protective effect of retarded removal of the unilateral necrotic testis after long-time (> 24 h) spermatic cord torsion on the contralateral testis in rats. METHODS: Thirty-three male SD rats aged 21 -42 days were divided into a sham-operation group (n = 11), a torsion-reservation group (n = 12) and a torsion-orchiectomy group (n = 10). The rats of the sham-operation group received dartos pouch orchidopexy on the left testis, while those of the latter two groups underwent 720 degrees unilateral spermatic cord torsion on the left side. Ninety-six hours later, the rats of the torsion-reservation group received detorsion with the ipsilateral testis preserved, while those of the torsion-orchiectomy group underwent orchiectomy. Three months after operation, blood samples were obtained from the rats for measurement of serum testosterone and antisperm antibodies by ELISA, and meanwhile testes and epididymides were harvested for determination of the volumes of various structures and the diameter of seminiferous tubules with stereological methods. RESULTS: There were no significant differences in the level of serum testosterone among the three groups. Anti-sperm antibody positive was found in only 1 animal in the torsion-reservation group. The Leydig cell nuclei in the contralateral testis appeared larger in the torsion groups than in the sham-operation group. Marked morphological changes were observed in 1, 3 and 0 of the animals in the sham-operation, torsion-reservation and torsion-orchiectomy group, respectively, mainly including atrophy of seminiferous tubules and reduced number of spermatogenic cells. The volume of the contralateral testis was increased by 19% and 21% in the torsion-reservation and torsion-orchiectomy group, respectively, in comparison with that in the sham-operation group (P < 0.05). No significant differences were observed in the volume of seminiferous tubules of the contralateral testis among the sham-operation, torsion-reservation and torsion-orchiectomy groups ([1.15 +/- 0.07], [1.30 +/- 0.04] and [1.35 +/- 0.05] cm3). The volume of the interstitial tissue was significantly increased in the latter two groups ([0.36 +/- 0.02 and 0.34 +/- 0.03] cm3) as compared with the former ([0.25 +/- 0.02] cm3) (P < 0.05). The diameters of the seminiferous tubules exhibited no significant differences among the three groups ([226.00 +/- 7.00], [223.00 +/- 6.00] and [221.00 +/- 3.0] microm). CONCLUSION: Long-time unilateral spermatic cord torsion may result in compensatory hypertrophy of the contralateral testis, and orchiectomy does not significantly affect the histology of the contralateral testis and epididymis.