Zona pellucida in the process of fertilization and mammal embryonal development

In mammals, oocytes, fertilized eggs and pre-implantation embryos are surrounded by an acellular zona pellucida (zona pellucida – ZP). This structure has a fibro-spongy character but it undergoes constant modifications throughout its existence depending on many internal and external factors. ZP consists of glycoproteins marked as ZP1, ZP2, ZP3 and ZP4, the presence of which is species different. ZP1 and probably ZP4 molecules stabilize the fibrillary skeleton of the zona pellucida formed of ZP2 and ZP3 protein polymers which are ligands for specific spermatozoid receptors. The oligosaccharide chains of ZP3 are responsible for the primary attachment of the male gamete which induces the acrosomal reaction. ZP2 enhances this connection by secondary binding to an acrosome-free spermatozoid. Additionally, oviductal specific glycoprotein 1 which plays a role in interspecific oocyte-sperm interactions, appears around the postovulatory oocyte surrounded by ZP. In addition, this protein modifies the resistance of ZP to the action of proteases released as a result of the cortical reaction during polyspermia block. After fertilization, ZP not only protects the egg and then the embryo until implantation, but also has an embryotrophic effect. Understanding the molecular basics of the structure and properties of ZP can significantly improve animal fertility as well as reproductive rates.

A Qualitative Validation of Two Diagrammatic Measures of Attachment Network Structure

In two qualitative evaluation studies, we explored the construct validity of two diagrammatic measures of attachment network structure, including the Bull’s Eye diagrammatic technique and a significantly modified version, the Web-based Hierarchical Mapping Technique (WHMT). In the first study, 20 young adults completed a Bull’s Eye diagram followed by a semi-structured interview in which participants explained their placement of support figures in their diagrams. Interview transcripts were analyzed using theory-driven thematic analysis to determine the presence of attachment-related themes, including safe haven, secure base effect, and proximity maintenance. Findings indicated mixed support for the Bull’s Eye as a measure of attachment networks. Although attachment themes were dominant among participants who identified a parent as their primary attachment figure, this was not the case among participants who identified a peer as a primary attachment figure. Participant justifications for peer attachments relied on non-attachment themes, including identity exploration and companionship. In the second study, we applied the same qualitative method to investigate the WHMT. Saturation was reached sooner, and attachment themes were dominant for both parent and peered primary attachment. Findings support the construct validity of the WHMT as a new measure of attachment network composition and strength.

Transfer of Early to Late Adolescents’ Attachment Figures in a Multicohort Six-Wave Study: Person- and Variable-Oriented Approaches

Although Bowlby proposed that adolescence is a major developmental period to transfer their attachment figures from parents to other people, no comprehensive longitudinal study on attachment transfer from early to late adolescence exists. This study employed 215 early to late adolescents between ages 11 and 18 years ([Formula: see text] = 14.02, SD = 2.05 at Wave 1), using a six-wave 2-year longitudinal design with four different cohorts: 5th, 7th, 9th, and 11th grades. Both person- and variable-oriented analyses revealed that once adolescents have transferred their attachment figures from parents to peers, they were unlikely to revert to parents in the future. The transfer of attachment from parents to friends is more prevalent in early adolescence than in late adolescence. However, throughout adolescence, friends were not considered to be exclusive attachment figures, whereas parents and romantic partners were. Finally, many adolescents spent 4 months or fewer until their romantic partner became the primary attachment figure.

Understanding and Treatment of Patients with Persistent Somatic Complaints Through the Lens of Contemporary Attachment Theory

This paper describes recent progress in our understanding of patients with persistent somatic complaints, based on a broad and integrative attachment approach. Attachment theory indeed provides a powerful lens through which to understand patients with persistent somatic complaints and the often extremely negative states in which they find themselves. It was Bowlby's genius to describe how the attachment system is activated in times of threat and distress and normatively serves to seek the proximity of others in an attempt to co-regulate stress. Yet, this primary attachment strategy typically increasingly fails when faced with the continuous distress associated with chronic somatic complaints. What often ensues is a negative vicious cycle characterised by an excessive reliance on secondary attachment strategies (either hyperactivation or deactivating the attachment system), problems with (embodied) mentalizing, and severe problems with epistemic trust, that is, trust in others as a reliable source of knowledge, including knowledge of the patient's physical and mental state. These issues are discussed in relation to Bowlby's original formulations and contemporary thinking about persistent somatic complaints and functional somatic disorders. We also summarise implications for clinical practice.

Function of attachment hierarchies in young adults experiencing the transition from university

An important cornerstone of Bowlby’s attachment theory (1969/1997) is the proposal that moving away from parents and toward peers is an indication of healthy development. In this study, we explored the benefit of the shift, not the shift itself, in a sample of emerging adults experiencing a stressful life event (i.e., the transition from university). Although the shift from parents to peers is an important cornerstone of Bowlby’s theory, this study is one of the first to test the differential effects of parent and peer networks on adjustment. In this longitudinal study, 73 participants completed surveys to assess attachment, social networks, and distress one month before completing their undergraduate degree and 6 months later. We found that participants experiencing the transition from university, who chose a peer as the first person in their network, tended to report stable scores over time whereas participants who chose a family member reported more variable scores. Interestingly, the direction of change was not different for the groups, just the magnitude of change. Furthermore, the difference in adjustment was not found when we compared the groups using the percent hierarchy method highlighting that there is a benefit of exploring primary attachment relationships when examining the influence of networks on adjustment.