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Biomarker-based sperm analysis elevates the treatment of human infertility and ameliorates reproductive performance in livestock. The negative biomarker-based approach focuses on proteins and ligands unique to defective spermatozoa, regardless of their morphological phenotype, lending itself to analysis by flow cytometry （FC）. A prime example is the spermatid specific thioredoxin SPTRX3/TXNDC8, retained in the nuclear vacuoles and superfluous cytoplasm of defective human spermatozoa. Infertile couples with high semen SPTRX3 are less likely to conceive by assisted reproductive therapies （ART） and more prone to recurrent miscarriage while low SPTRX3 has been associated with multiple ART births. Ubiquitin, a small, proteolysis-promoting covalent posttranslational protein modifier is found on the surface of defective posttesticular spermatozoa and in the damaged protein aggregates, the aggresomes of spermiogenic origin. Semen ubiquitin content correlates negatively with fertility and conventional semen parameters, and with sperm binding of lectins LCA （Lens culinaris agglutinin; reveals altered sperm surface） and PNA （Arachis hypogaealpeanut agglutinin; reveals acrosomal malformation or damage）. The Postacrosomal Sheath WWl Domain Binding Protein （PAWP）, implicated in oocyte activation during fertilization, is ectopic or absent from defective human and animal spermatozoa. Consequently, FC-parameters of PAWP correlate with ART outcomes in infertile couples and with fertility in bulls. Assays based on the above biomarkers have been combined into multiplex FC semen screening protocols, and the surface expression of lectins and ubiquitin has been utilized to develop nanoparticle-based bull semen purification method validated by field artificial insemination trials. These advances go hand-in-hand with the innovation of FC-technology and genomics/proteomics-based biomarker discovery.

The scope of paternal contributions during early embryonic development has long been considered limited. Dramatic changes in chromatin structure throughout spermatogenesis have been thought to leave the sperm void of complex layers of epigenetic regulation over the DNA blueprint, thus leaving the balance of that regulation to the oocyte. However, recent work in the fields of epigenetics and male factor infertility has placed this long-held, and now controversial dogma, in a new light. Elegant studies investigating chromatin and epigenetic modifications in the developing sperm cell have provided new insights that may establish a more critical role for the paternal epigenome in the developing embryo. DNA methylation, histone tail modifications, targeted histone retention and protamine incorporation into the chromatin have great influence in the developing sperm cell. Perturbations in the establishment and/or maintenance of any of these epigenetic marks have been demonstrated to affect fertility status, ranging in severity from mild to catastrophic. Sperm require this myriad of chromatin structural changes not only to serve a protective role to DNA throughout spermatogenesis and future delivery to the egg, but also, it appears, to contribute to the developmental program of the future embryo. This review will focus on our current understanding of the epigenetics of sperm. We will discuss sperm-specific chromatin modifications that result in genes essential to development being poised for activation early in embryonic development, the disruption of which may result in reduced fecundity.

Spermatozoa are constantly exposed to the interphase between oxidation through high amounts of reactive oxygen species （ROS） and leukocytes, and reduction by means of scavengers and antioxidants. Considering the very special functions as being the only cells with such high polarization and exerting their functions outside the body, even in a different individual, the female genital tract, the membranes of these cells are chemically composed of an extraordinary high amount of polyunsaturated fatty acids. This in turn, renders them very susceptible to oxidative stress, which is defined as an imbalance between oxidation and reduction towards the oxidative status. As a result, ROS deriving from both leukocytes and the male germ cells themselves cause a process called ＇lipid peroxidation＇ and other damages to the sperm cell. On the other hand, a certain limited amount of ROS iS essential in order to trigger vital physiological reactions in cells, including capacitation or the acrosome reaction in sperm. The treatment of patients with antioxidants to compensate the oxidative status caused by oxidative stress is highly debated as uncontrolled antioxidative treatment might derail the system towards the reduced status, which is also unphysiological and can even induce cancer. This paradox is called the ＇antioxidant paradox＇. Therefore, a proper andrological diagnostic work-up, including the evaluation of ROS levels and the antioxidant capacity of the semen, has to he carried out beforehand, aimed at keeping the fine balance between oxidation and scavenging of vital amounts of ROS.

Recent data from several laboratories have provided evidence that the newly fertilized oocyte inherits epigenetic signals from the sperm chromatin that are required for proper embryonic development. For the purposes of this review, the term epigenetic is used to describe all types of molecular information that are transmitted from the sperm cell to the embryo. There are at least six different forms of epigenetic information that have already been established as being required for proper embryogenesis in mammals or for which there is evidence that it may do so. These are （i） DNA methylation; （ii） sperm-specific histones, （iii） other chromatin-associated proteins; （iv） the perinuclear theca proteins; （v） sperm-born RNAs and, the focus of this review; and （vi） the DNA loop domain organization by the sperm nuclear matrix. These epigenetic signals should he considered when designing protocols for the manipulation and cryopreservation of spermatozoa for assisted reproductive technology as necessary components for effective fertilization and subsequent embryo development.

The foundations of proteomics are to study gene products and their regulatory roles within cells. Paradoxically, the only evidence that sperm cells make new proteins is through mitochondrial protein synthesis. Yet despite this, spermatozoa are the perfect candidates for mass spectrometry and hence, proteomic analysis. These enterprising cells use a plethora of post-translational modifications in order to gain functionality following their production within the testis. By using a combination of two-dimensional polyacrylamide gel electrophoresis （2D-PAGE）, and more recently liquid chromatography-mass spectrometry （LC-MS）/MS, recent advances in sperm cell biology, through the use of proteomics, is making unparalleled progress. The protein inventory lists being generated have shed light on transmembrane proteins, kinases and chaperones never previously recognized. In addition, the ability to isolate either phosphopeptides or glycopeptides and quantify the differences between cells of two different populations make proteomic analysis of spermatozoa a real chance to finally answer some age old questions.

The 12th International Symposium of Spermatology continued the excellent tradition of this meeting since its inception in 1969 when the first Symposium was held in Italy under the Chairmanship of Professor Baccio Baccetti. This unique Symposium is held every 4 years and serves as a beacon for sperm cell biologists from all over the world, regardless of which species, animal or plant, they are working on. This willingness to embrace the fundamental biology of this distinctive cell type without species limitations is one of the hallmarks of this Symposium. For sperm biologists - it is our Olympics. The meeting in Newcastle, NSW brought together around 300 biologists from more than 22 different countries covering North and South America, Africa, Europe, Asia and Australia. Given the considerable distances and high cost involved in travelling to the East Coast of NSW, this was an outstanding outcome. The Symposium featured a series of 31 plenary lectures culminating in the prestigious Thaddeus Mann Memorial Lecture, which was delivered with typical grace and brilliance by Professor Masaru Okabe.

The manuscript by Ozkavukcu et al. provides the demonstration that a simple change in laboratory procedure can lead to a significant improvement in technical outcome, that is, sperm cells extraction from testicular tissue.

MIWI and PIWI-interacting RNA （piRNA）, which binds to PIWIfamily members including MIWI, contri- bute to post-transcriptional regulation in spermiogenesis, however, their molecular functions had been unclear. Recently, Zhao and colleagues reported that loading of piRNA to MIWI leads to ubiquitin-pro- teasome mediated degradation in late spermatid and that this process is essential for the maturation from late spermatid to sperm. This paper casts a novel insight on the function of MIWI and the interaction between piRNA and the PIWI family mem- ber in spermatogenesis.

Aminopeptidase N （APN/CD13） and neutral endopeptidase （NEP/CD10） are enzymes present in human sperm cells and involved in regulation of sperm motility of noncapacitated spermatozoa. We investigated the involvement of APN/CD 13 and NEP/CD 10 in motility and in kinematic parameters of human capacitated spermatozoa. Sperm cells isolated by a discontinuous Percoll gradient （40%-80%） followed up by swim-up techniques were incubated with the APN/CD 13 -specific inhibitor, leuhistin （100 μmol L^-1）, and the NEP/CD 10-specific inhibitor, thiorphan （1 μmol L^-1）. The complete inhibition of both APN/CD 13 and NEP/CD 10 improved sperm motility. Spermatozoa incubated with the APN/CD13-specific inhibitor lenhistin showed asymmetrical trajectories, whereas sperm trajectories were more regular after treatment with the NEP/CD 10-specific inhibitor thiorphan. In conclusion, APN/CD 13 and NEP/CD 10 modulate the motility of capacitated spermatozoa, although each of the enzymes seems to participate in the control of different aspects of sperm motility. Therefore, both inhibitors may be useful for sperm activation at different functional stages of spermatozoa.

Sexual reproduction of flowering plants depends on the delivery of two immotile sperm cells to the female gametophyte（FG）,i.e.the embryo sac,through the growth of a pollen tube,a long cylindrical cellular extension from a pollen grain.The journey of pollen tubes toward the embryo sacs is led by female cues,which guide the path of the pollen tubes.