Deficiency of TPPP2, a factor linked to oligoasthenozoospermia,causes subfertility in male mice

Oligoasthenozoospermia is a major cause of male infertility; however, its etiology and pathogenesis are unclear and may be associated with specific gene abnormalities. This study focused on Tppp2 (tubulin polymerization promoting protein family member 2), whose encoded protein localizes in elongating spermatids at stages IV‐VIII of the seminiferous epithelial cycle in testis and in mature sperm in the epididymis. In human and mouse sperm, in vitro inhibition of TPPP2 caused significantly decreased motility and ATP content. Studies on Tppp2 knockout (KO) mice demonstrated that deletion of TPPP2 resulted in male subfertility with a significantly decreased sperm count and motility. In Tppp2^?/? mice, increased irregular mitochondria lacking lamellar cristae, abnormal expression of electron transfer chain molecules, lower ATP levels, decreased mitochondrial membrane potential and increased apoptotic index were observed in sperm, which could be the potential causes for its oligoasthenozoospermia phenotype. Moreover, we identified a potential TPPP2‐interactive protein, eEf1b (eukaryotic translation elongation factor 1 beta), which plays an important role in protein translation extension. Thus, TPPP2 is probably a potential pathogenic factor in oligoasthenozoospermia. Deficiency of TPPP2 might affect the translation of specific proteins, altering the structure and function of sperm mitochondria, and resulting in decreased sperm count, motility and fertility.     

细胞质雄性不育水稻幼穗和花药的呼吸酶活性研究

研究珍汕97A和珍汕97B的雌雄蕊原基形成期、花粉母细胞形成期和花粉母细胞减数分裂期的幼穗及单核期、二核期和三核期的花药中呼吸代谢三羧酸循环（TCA）的苹果酸脱氢酶（MDH）和异柠檬酸脱氢酶（IDH）及戊糖途径（PPP）的磷酸葡萄糖脱氢酶（G6PDH）、磷酸葡萄糖酸脱氢酶（6PGDH）和5一磷酸核糖异构酶（RSPI）的活性。结果表明：可育花药的5种酶活性皆高于同期不育花药;而幼穗中,TCA途径中的MDH和IDH在不育系与保持系之间无差异,PPP途径的G6PDH和6PGDH及R5PI则保持系高于不育系。这说明不育系中PPP发生的变化早于TCA途径,PPP途径的改变可能与小孢子败育有着更为直接的关系。     

Development of Anther- defective Cytoplasmic Male Sterile Line from Interspecific Hybridization Between Dongxiang Wild Rice and Cultivated Rice and Preliminary Observations on Its Derivatives

Exploring novel source of cytoplasmic male sterility (CMS) is essential to stablize the productivity of hybrid rice. Dongxiang wild rice ( Oryza rufipogon Griff. ) has been recorded as the northest distributed wild rice in China that is resistant to several biotic or abiotic stresses. A male sterile line M01A defective of anther was identified in the F3 population from an interspecific cross between Dongxiang wild rice and cultivated rice ( Oryza sativa L. ssp. indica ). Crosses and successive backcrosses were made between M01A and a variety of breeding materials and 19 progeny families were obtained. Among the families, some were defective of anthers, and some have twisted and degenerated anthers without microsporogenesis or with a few typical aborted pollen. These resuits implicate that the male sterility of M01A was genetically regulated by the interaction between the nucleus and the cytoplasm. Only one cross produced male-fertile hybrid in which the paternal parent contains a part of the genome of Dongxiang wild rice, which implies that Dongxiang wild rice itself could be the source of the fertility restorer to M01A.     

辣椒细胞质雄性不育与活性氧代谢的关系

通过测定辣椒保护酶活性和膜脂过氧化产物,研究了辣椒胞质雄性不育三系与膜脂过氧化的关系.结果表明,从花粉母细胞减数分裂前至花粉成熟期,三系之间SOD活性无明显差异,不育系花药中的CAT和POD活性均显著或极显著低于保持系和恢复系,而O2-·产生效率、MDA含量则显著或极显著高于保持系和恢复系.同时,在花药发育过程中,由于质、核差异,保持系的CAT活性明显高于恢复系,SOD和POD活性保持系和恢复系之间无明显差异.     

水稻红莲型细胞质雄性不育系小孢子不同发育时期花药总蛋白质比较分析

采用双向凝胶电泳对水稻红莲型细胞质雄性不育的不育系小孢子发育单核期和二核期花药总蛋白进行了分离,通过银染显色,获得了分辨率和重复性较好的双向电泳图谱,且单核期和二核期花药总蛋白质在双向电泳胶上分布的图谱十分相似。PDQuest 2DE图像分析软件在等电点(pI)3.0~10.0、分子量(M.W.)9.0~98.0 kD之间可识别约1 800个蛋白质点。比较分析发现单核期和二核期花药中共有241个差异表达的蛋白质点,其中仅在单核期中表达的点数为125,仅在二核期中表达的为13点;表现为表达量差异的105点,其中在二核期表达下调的点数为70点,表达上调的为33点。还对蛋白质点集中的区域(pI 4.5~8.0,M.W.25.0~70.0 kD)中的41个差异蛋白质点进行了分子量和等电点分析。     

Hypo-osmotic swelling can accurately assess the viability of nonmotile sperm

Viable, healthy sperm are preferred for oocyte fertilization with intracytoplasmic sperm injection. Currently, motility is the most widely applied measure of sperm viability. However, with this criterion, viable but immotile sperm are overlooked as candidates for micromanipulation. Supravital stains identify viable sperm but may be toxic to the gamete or embryo. We tested the hypothesis that hypo-osmotic swelling, developed to assess sperm membrane integrity, can accurately determine sperm viability. Thawed sperm from 12 fertile donors were exposed to a hypo-osmotic solution and to two supravital stains. A total of 2,010 sperm were assessed for tail coiling after a 30-min exposure to hypo-osmotic solution. By supravital stains, 31% of thawed sperm were viable; 23% showed tail coiling. Among coiled-tail sperm, 100% were viable by supravital stain. As a measure of viability, tail coiling exhibited a sensitivity of 30%, specificity of 100%, and positive predictive value of 100% compared to supravital stains. With a 60-min hypo-osmotic incubation, the specificity (89%) and positive predictive value (78%) decreased significantly (P < 0.05). Therefore, hypo-osmotic swelling accurately detects viable sperm among a nonmotile population. Assay accuracy, however, is very sensitive to the incubation time in hypo-osmotic solution. Mol. Reprod. Dev. 47:200–203, 1997. © 1997 Wiley-Liss, Inc.     

Another functional frame‐shift polymorphism of DEFB126 (rs11467497) associated with male infertility

DEFB126 rs140685149 mutation was shown to cause sperm dysfunction and subfertility. Indel rs11467497 is another 4‐nucleotide frame‐shift mutation (151bp upstream of rs140685149) that leads to the premature termination of translation and the expression of peptide truncated at the carboxyl terminus. In the present study, we performed a comprehensive association study to check the contribution of rs140685149 and rs11467497 to male infertility. Our results confirmed the previous findings that there was no association between rs140685149 and sperm motility. In contrast, we found a significant association of another indel rs11467497 with male infertility. Moreover, rs11467497 was shown to be associated with higher number of round cells in the infertile males with low sperm motility. Surprisingly, the two mutations commonly existed in the sperm donors (n = 672), suggesting a potential application of the two indels in the screening for eligible sperm donors. Western blotting assays showed the sperms with rs140685149 2‐nt deletion tended to have unstable DEFB126 protein in contrast of no DEFB126 protein expressed in the sperms with rs11467497 4‐nt deletion, suggesting a more severe consequence caused by rs11467497 mutation. In conclusion, our study presented a significant contribution of another functional frame‐shift polymorphism of DEFB126 (rs11467497) to male infertility.     

Effects of Age and Experience on Male Mate Choosiness

Mate choosiness by males has been documented in many taxa but we still do not know how it varies with age even though such variation can be important for our understanding of sexual selection on females. Theory provides conflicting predictions: young males, who are less attractive to females than older males, may be less choosy, or older males, who face fewer expected future mating opportunities, may be less choosy. In our experiments with fruit flies (Drosophila melanogaster), young (1‐d‐old) males spent relatively less time courting recently mated females than did mature (4‐d‐old) males. Overall, there was a gradual decline in male mate choosiness from age 1–7 d. As male age was correlated with the duration of deprivation from females, we tested for the effect of deprivation and found that same‐age males previously exposed to females were choosier than female‐deprived males. We also assessed key male parameters that could affect choosiness and found that, compared to mature males, young males were less attractive to females, less competitive in intramale interactions and less fertile. Although the lesser attractiveness and competitiveness should select for lesser mate choosiness in young males, their limited fertility and more expected future mating opportunities seem to override the other factors and lead to high mate choosiness in young males. Overall, our data indicate that young males just after reaching sexual maturity are choosy and that subsequent exposure to females can maintain high levels of male mate choosiness with age. Hence, males can contribute much more to sexual selection than previously appreciated.