Bisphenol A (BPA), an endocrine-disrupting chemical, is widely used in the manufacture of daily necessities. Previous studies showed that BPA could impair spermatogenesis. However, its effects on mature spermatozoa are not well known. We aimed to investigate the in vivo and in vitro toxicity of BPA on mature mouse spermatozoa. Different doses of BPA (0, 10, 50, and 250 μg·kg(-1)·d(-1)) were administrated orally to C57BL/6 mice for 8 weeks. Subsequently, the sperm viability, motility, acrosome reaction (AR) ratio together with the expression/current levels of the sperm-specific Ca(2+ )channel (CatSper) and K(+ )channel (KSper) were examined. These parameters were also evaluated after applying BPA directly to normal mouse sperm to appraise the toxicity of BPA to mature sperm in vitro Significant decreases in sperm motility and AR were found in BPA administrated mice, possibly resulting from a BPA caused CatSper down-regulation which was supported by both western blot and patch clamping results. Moreover, direct application of BPA to spermatozoa inhibited CatSper transiently and also caused significant reductions in sperm total motility and AR ratio. In conclusion, both in vivo administration and in vitro application of BPA impair mature sperm functions by a CatSper-relevant mechanism.

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Following entry into the female reproductive tract, mammalian sperm undergo a maturation process termed capacitation that results in competence to fertilize ova. Associated with capacitation is an increase in membrane conductance to both Ca 2+ and K + , leading to an elevation in cytosolic Ca 2+ critical for activation of hyperactivated swimming motility. In mice, the Ca 2+ conductance (alkalization-activated Ca 2+ -permeable sperm channel, CATSPER) arises from an ensemble of CATSPER subunits, whereas the K + conductance (sperm pH-regulated K + current, KSPER) arises from a poreforming ion channel subunit encoded by the slo3 gene (SLO3) subunit. In the mouse, both CATSPER and KSPER are activated by cytosolic alkalization and a concerted activation of CATSPER and KSPER is likely a common facet of capacitation-associated increases in Ca 2+ and K + conductance among various mammalian species. The properties of heterologously expressed mouse SLO3 channels differ from native mouse KSPER current. Recently, a potential KSPER auxiliary subunit, leucine-rich-repeat-containing protein 52 (LRRC52), was identified in mouse sperm and shown to shift gating of SLO3 to be more equivalent to native KSPER. Here, we show that genetic KO of LRRC52 results in mice with severely impaired fertility. Activation of KSPER current in sperm lacking LRRC52 requires more positive voltages and higher pH than for WT KSPER. These results establish a critical role of LRRC52 in KSPER channels and demonstrate that loss of a non-pore-forming auxiliary subunit results in severe fertility impairment. Furthermore, through analysis of several genotypes that influence KSPER current properties we show that in vitro fertilization competence correlates with the net KSPER conductance available for activation under physiological conditions. sperm fertility | KSPER | SLO3 channels | auxiliary subunits U pon entry into the female reproductive tract, mammalian sperm undergo a sequence of maturational steps, collectively termed capacitation, to become competent to fertilize an egg (1, 2). Two important components of this process, thought to be shared among mammalian species, are cytosolic alkalization (3-5) and then an associated increase in cytosolic Ca 2+ (6, 7). These events are coupled with changes in ionic fluxes in sperm membrane. Over the past 10 y, the application of patch-clamp recording to individual sperm (8) has allowed identification of ionic currents that respond to alkalization and/or Ca 2+ (9-12). In mouse sperm, alkalization leads to activation of two spermspecific channels, the Ca 2+ -permeable CATSPER channel (8-10, 13) and the K + -permeable KSPER K + channel (14, 15). KSPER and CATSPER currents are also present in human sperm (16-18), although intriguingly there seem to be differences in regulation of each channel type between mice and humans (11,12,17).Despite the species-specific differences in the details of their regulation, KSPER and CATSPER are of central importance in sperm function and fertility in both humans and mice. In mouse spe...

SUMMARYA multi-objective optimization procedure is presented for designing steel moment resisting frame buildings within a performance-based seismic design framework. Life cycle costs are considered by treating the initial material costs and lifetime seismic damage costs as two separate objectives. Practical design=construction complexity, important but di cult to be included in initial cost analysis, is taken into due account by a proposed diversity index as another objective. Structural members are selected from a database of commercially available wide ange steel sections. Current seismic design criteria (AISC-LRFD seismic provisions and 1997 NEHRP provisions) are used to check the validity of any design alternative. Seismic performance, in terms of the maximum inter-storey drift ratio, of a codeveriÿed design is evaluated using an equivalent single-degree-of-freedom system obtained through a static pushover analysis of the original multi-degree-of-freedom frame building. A simple genetic algorithm code is used to ÿnd a Pareto optimal design set. A numerical example of designing a ÿve-storey perimeter steel frame building is provided using the proposed procedure. It is found that a wide range of valid design alternatives exists, from which a decision maker selects the one that balances di erent objectives in the most preferred way.

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