Bitterlings are carp-like teleost fish (Cypriniformes: Acheilanathidae) known for their specialized brood parasitic lifestyle. Bitterling embryos, in fact, develop inside the gill chamber of their... Show moreBitterlings are carp-like teleost fish (Cypriniformes: Acheilanathidae) known for their specialized brood parasitic lifestyle. Bitterling embryos, in fact, develop inside the gill chamber of their freshwater mussel hosts. However, little is known about how their parasitic lifestyle affects brain development in comparison to nonparasitic species. Here, we document the development of the brain of the rosy bitterling, Rhodeus ocellatus, at four embryonic stages of 165, 185, 210, 235 hours postfertilization (hpf) using micro-computed tomography (microCT). Focusing on developmental regionalization and brain ventricular organization, we relate the development of the brain divisions to those described for zebrafish using the prosomeric model as a reference paradigm. Segmentation and three-dimensional visualization of the ventricular system allowed us to identify changes in the longitudinal brain axis as a result of cephalic flexure during development. The results show that during early embryonic and larval development, histological differentiation, tissue boundaries, periventricular proliferation zones, and ventricular spaces are all detectable by microCT. The results of this study visualized with differential CT profiles are broadly consistent with comparable histological studies, and with the genoarchitecture of teleosts like the zebrafish. Compared to the zebrafish, our study identifies distinct developmental heterochronies in the rosy bitterling, such as a precocious development of the inferior lobe. Show less
We developed the bitterling as a unique, well-studied model organism in the area of the evolutionary ecology of brood parasitism. The bitterling-mussel relationship, interspecific mussel host... Show moreWe developed the bitterling as a unique, well-studied model organism in the area of the evolutionary ecology of brood parasitism. The bitterling-mussel relationship, interspecific mussel host preference, and mussel gill structure are studied in detail, to help understand the developmental adaptation of bitterling embryos in response to their mussel hosts. Our complete stage series of the bitterling species R. ocellatus in Chapter 2 is a new, character-based systems that are compatible with the widely-used zebrafish staging system. With time-lapse video, we demonstrated the dynamic processes of hatching moment of the rosy bitterling in real time, which indicates the hatching process is mechanical rather than enzymatic. In Chapter 3, we described the neuroanatomy of bitterling for the first time, filling the gaps in the previous embryonic research in various bitterling taxa. Combined with the molecular analysis of brain early development in Chapter 4, brain development in the rosy bitterling is compared with that in the zebrafish. In Chapter 5, we studied the morphogenetic process of blastokinesis in the bitterling embryo, and its possible relation to brood parasitism. Show less
Bitterlings, a group of freshwater teleosts, provide a fascinating example among vertebrates of the evolution of brood parasitism. Their eggs are laid inside the gill chamber of their freshwater... Show moreBitterlings, a group of freshwater teleosts, provide a fascinating example among vertebrates of the evolution of brood parasitism. Their eggs are laid inside the gill chamber of their freshwater mussel hosts where they develop as brood parasites. Studies of the embryonic development of bitterlings are crucial in deciphering the evolution of their distinct early life-history. Here, we have studied 255 embryos and larvae of the rosy bitterling (Rhodeus ocellatus) using in vitro fertilization and X-ray microtomography (microCT). We describe 11 pre-hatching and 13 post-hatching developmental stages spanning the first 14 days of development, from fertilization to the free-swimming stage. In contrast to previous developmental studies of various bitterling species, the staging system we describe is character-based and therefore more compatible with the widely-used stages described for zebrafish. Our bitterling data provide new insights into to the polarity of the chorion, and into notochord vacuolization and yolk sac extension in relation to body straightening. This study represents the first application of microCT scanning to bitterling development and provides one of the most detailed systematic descriptions of development in any teleost. Our staging series will be an important tool for heterochrony analysis and other comparative studies of teleost development, and may provide insight into the co-evolution of brood parasitism. Show less
In this paper, we study the scheduling problem of the imprecise mixed-criticality model (IMC) under earliest deadline first with virtual deadline (EDF-VD) scheduling upon uniprocessor systems. Two... Show moreIn this paper, we study the scheduling problem of the imprecise mixed-criticality model (IMC) under earliest deadline first with virtual deadline (EDF-VD) scheduling upon uniprocessor systems. Two schedulability tests are presented. The first test is a concise utilization-based test which can be applied to the implicit deadline IMC task set. The suboptimality of the proposed utilization-based test is evaluated via a widely-used scheduling metric, speedup factors. The second test is a more effective test but with higher complexity which is based on the concept of demand bound function (DBF). The proposed DBF-based test is more generic and can apply to constrained deadline IMC task set. Moreover, in order to address the high time cost of the existing deadline tuning algorithm, we propose a novel algorithm which significantly improve the efficiency of the deadline tuning procedure. Experimental results show the effectiveness of our proposed schedulability tests, confirm the theoretical suboptimality results with respect to speedup factor, and demonstrate the efficiency of our proposed algorithm over the existing deadline tunning algorithm. In addition, issues related to the implementation of the IMC model under EDF-VD are discussed. Show less
