Use of Nanotechnology and Phytochemical Approaches to Investigate Boar Spermatozoa

Mass semen production for genetic conservation and large commercialization is considerably limited in the swine industry. Boar semen have specific features that prevent mid- and long-term preservation in cooling and freezing extenders, respectively. The success of long-term semen preservation in liquid nitrogen following deep-freezing, also known as cryopreservation, is drastically limited in swine farms. Meanwhile, the preservation of chilled extended boar semen has limitations due to the progressive decrease of sperm fertility potential during storage. With the ultimate goal of producing high quality semen for larger distribution, there is a need to investigate novel approaches to improve boar semen quality, especially during chilled storage. This study is composed of three sets of experiments. Firstly, we processed extended boar semen in the laboratory to determine the ideal condition for handling spermatozoa in the following experiments. Secondly, we took advantage of the high brightness, photostability, and bio-conjugation capabilities of quantum dot nanoparticles (QD) to investigate sperm features through non-invasive molecular-based fluorescence imaging. The QD were conjugated with two low-abundant and small polypeptide hormones, arginine vasotocin (AVT) and gonadotropin-releasing hormone (GnRH). Fluorescence detection of both AVT and GnRH membrane receptors was enabled by conjugated QD-AVT and QD-GnRH binding to freshly harvested boar spermatozoa, followed by fluorescence imaging of labeled spermatozoa. The effects of QD-AVT and QD-GnRH binding on sperm motility and morphology characteristics were assessed with the Computer-Assisted Sperm Analyzer (CASA). The findings suggested the presence of AVT and GnRH receptors on boar spermatozoa, and the sperm labeling with QD conjugates did not significantly affect the motility or morphology characteristics. Thirdly, we studied the Gum Arabic (GA) phytochemical, a biopolymer extracted from the Acacia tree, which is used for various purposes in bio-industries. Various concentrations of GA were added to semen in commercial extender and the mixtures were stored for up to 7 days at ~18oC. Sperm quality parameters were analyzed at different time points during storage. Overall, spermatozoa stored with 25µg of GA exhibited higher motility, progressivity, and normal morphology compared to the control, without any GA supplementation. The results of this experiment indicate that non-invasive bioimaging through nanoparticle conjugates could be an effective way to improve the current understanding of sperm biology and mammalian reproductive processes. Furthermore, the use of the GA biopolymer shows great promise in maintaining and improving sperm quality during chilled storage

An authentic discourse: Recentering race and racism as factors that contribute to police violence against unarmed Black or African American men

<p>This study explores the relationship between race, racism, and attitudes toward police violence against adult males. Study participants comprised a national sample (<i>N = </i>1,974) of adult males and females (<i>M</i> = 48 years) who completed the 2012 General Social Survey (GSS). Secondary data analysis of surveys administered in-person or on the telephone by trained GSS interviewers indicated that race is a key predictor of police violence against adult males [χ² (7) = 85.710, <i>p < </i>.0001], even after controlling for sex, education, income, and age. Study findings also revealed that attitudes supportive of police violence are associated with negative cultural images of Blacks or African Americans. Participants who approved of police violence against males attributed disparities in employment, income, and housing between Blacks or African Americans and Whites to a lack of motivation and ability to learn, rather than to racial discrimination and lack of education incurred through poverty. These findings challenge us as social work educators and practitioners to further explore the association between racism and police violence and to unmask the debilitating consequences of the presumed limitations of Blacks or African Americans.</p