Identification of the Inorganic Pyrophosphate Metabolizing, ATP Substituting Pathway in Mammalian Spermatozoa

Inorganic pyrophosphate (PPi) is generated by ATP hydrolysis in the cells and also present in extracellular matrix, cartilage and bodily fluids. Fueling an alternative pathway for energy production in cells, PPi is hydrolyzed by inorganic pyrophosphatase (PPA1) in a highly exergonic reaction that can under certain conditions substitute for ATP-derived energy. Recombinant PPA1 is used for energy-regeneration in the cell-free systems used to study the zymology of ATP-dependent ubiquitin-proteasome system, including the role of sperm-borne proteasomes in mammalian fertilization. Inspired by an observation of reduced in vitro fertilization (IVF) rates in the presence of external, recombinant PPA1, this study reveals, for the first time, the presence of PPi, PPA1 and PPi transporter, progressive ankylosis protein ANKH in mammalian spermatozoa. Addition of PPi during porcine IVF increased fertilization rates significantly and in a dose-dependent manner. Fluorometric assay detected high levels of PPi in porcine seminal plasma, oviductal fluid and spermatozoa. Immunofluorescence detected PPA1 in the postacrosomal sheath (PAS) and connecting piece of boar spermatozoa; ANKH was present in the sperm head PAS and equatorial segment. Both ANKH and PPA1 were also detected in human and mouse spermatozoa, and in porcine spermatids. Higher proteasomal-proteolytic activity, indispensable for fertilization, was measured in spermatozoa preserved with PPi. The identification of an alternative, PPi dependent pathway for ATP production in spermatozoa elevates our understanding of sperm physiology and sets the stage for the improvement of semen extenders, storage media and IVF media for animal biotechnology and human assisted reproductive therapies

Examining the acceptance and use of online social networks by preservice teachers within the context of unified theory of acceptance and use of technology model

Social network sites (SNSs) has a big potential to improve teaching and learning experience. It has become a necessity for teachers to transfer this technologies to learning environments has become a requirement. For this reason, the use of SNSs in the education process of preservice teachers who are the teachers of the future and examination of variables that have an impact on the acceptance of these technologies are found important. The use of SNSs in teacher education will enable preservice teachers to be more willing to use information technologies and will improve their skills in using these technologies. For the reasons given, in this study, it is aimed to examine the acceptance and use of SNSs by preservice teachers for educational purposes on the basis of unified theory of acceptance and use of technology model. The study was designed according to relational screening model. Study group of the study consists of 274 preservice teachers at a university in 2017. Data were collected via various scales and personal information form at the end of an application process of 14weeks+14weeks. Descriptive statistics, linear multiple hierarchical regression analysis and structural equation model were used in analysing the data. As a result of the study, it was determined that the acceptance of SNSs for educational purposes was affected respectively by social effect, performance expectation and effort expectation, and behavioral intention of using these technologies affected the actual use. Besides, variables of moderators that were effective on acceptance and use were also determined

Harnessing genomic information for livestock improvement.

The world demand for animal-based food products is anticipated to increase by 70% by 2050. Meeting this demand in a way that has a minimal impact on the environment will require the implementation of advanced technologies, and methods to improve the genetic quality of livestock are expected to play a large part. Over the past 10 years, genomic selection has been introduced in several major livestock species and has more than doubled genetic progress in some. However, additional improvements are required. Genomic information of increasing complexity (including genomic, epigenomic, transcriptomic and microbiome data), combined with technological advances for its cost-effective collection and use, will make a major contribution