Context Telomerase reverse transcriptase is a key factor responsible for structural and cellular alterations in aged oocytes and changes in the structure of the zona pellucida and mitochondria. Telomerase expression is reduced in aged cumulus oocyte complexes, and its activation or enhanced expression would be beneficial for in vitro oocyte maturation and in vitro embryo development. Aims This study aimed to investigate telomerase activation by cycloastragenol and its effect on bovine oocyte in vitro maturation, fertilisation, and early embryo development. Methods We used qPCR, Western blot, immunofluorescence, reactive oxygen species (ROS) assay,TUNEL assay, JC-1 assay, and invasion assay to analyse the affect of cycloastragenol (CAG) on bovine oocyte maturation, embryo development, embryo quality and implantation potential. Key results Cycloastragenol treatment of oocytes in in vitro maturation (IVM) media significantly (P < 0.05) improved oocyte IVM (90.87%), embryo cleavage (90.78%), blastocyst hatching (27.04%), and embryo implantation potential. Telomerase also interacts with mitochondria, and JC-1 staining results showed significantly (P < 0.05) higher mitochondrial membrane potential (ΔΨm) in the CAG-treated group. Furthermore, the inner cell mass (OCT4 and SOX2) and trophoblasts (CDX2) of the control and CAG groups were examined. Moreover, CAG treatment to primary cultured bovine cumulus cells substantially enhanced telomerase activity. Conclusions Telomerase activation via cycloastragenol is beneficial for bovine oocyte IVM and for the production of high-quality bovine embryos. Implications Cycloastragenol is a natural telomerase activator, and could be useful as a permanent component of oocyte maturation media.
The problem of schedule delay is a frequent and regular phenomenon in the construction projects. Road construction of Sri Lanka is no exception. Client as a key project participant has a control on duration of construction phases. This makes client a casual cause for schedule delay. However, contractor also is a major suffering party due to unprecedented delays. Therefore, this research is aimed at investigating the contractor's perspective of client's impact to the schedule delay in rehabilitation and widening road projects (RWRP) in Sri Lanka. Initially, a comprehensive literature review aided to identify types and effects of delay in road construction projects. Further, identified literature was refined in the sense of Sri Lankan context through three number of preliminary interviews. Next, six cases were selected considering RWRPs in Sri Lanka and steered a document review to investigate the influence of the involvement of the client for delays. Then, a questionnaire survey was carried out to examine the significance of client's causes for delay on contractor's perspective and to identify the client's best practices including suggestions to minimize the delays in RWRPs in Sri Lanka. The analysed data confirmed that delayed interim payments to the contractors due to monetary difficulties of the client, change orders by the client throughout the construction period, delay in land acquisition and delay in handing over the site for construction work as key client causative factors. This study request client to adhere with the identified best practices to mitigate schedule delays in RWRP in Sri Lanka.
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