Does the belt and road initiative reduce the carbon emission intensity of African participating countries?

The ambition of the Belt and Road Initiative (BRI) became an integral part of carbon emission abatement. The BRI impact on African participating countries' battle against carbon emissions intensity is a contentious subject. Urbanization and industrialization are the main sources of CO2 emissions in Africa and the driving force in the BRI. Using data on variables from 2010 to 2019 in 54 African countries, applying Difference-in-differences model (DID) and Propensity Score Matching-Difference-in-differences regression (PSM-DID), and robustness tests to investigate if the BRI's participation tends to reduce the carbon emissions intensity of African participating countries. This study finds that African countries' participation in the BRI minimizes the intensity of carbon emissions in those countries. Further analysis shows that low carbon development of BRI countries is more significant in countries that joined the BRI than those that did not join it. In addition, our results show that improving economic transformation such as the innovation in technology and industries' structures can boost the CO2 emission reduction technologies. These findings suggest that developing BRI collaboration with China will benefit the environment and African BRI participating countries' ability to achieve sustainable development. Our results further support the BRI's effect and recommend policy implications and methods for those countries' CO2 emission prevention and control actions.

The thrombospondin type 1 repeat (TSR) and neuronal differentiation: roles of SCO-spondin oligopeptides on neuronal cell types and cell lines.

SCO-spondin is a large glycoprotein secreted by ependymal cells of the subcommissural organ. It shares functional domains called thrombospondin type 1 repeats (TSRs) with a number of developmental proteins expressed in the central nervous system, and involved in axonal pathfinding. Also, SCO-spondin is highly conserved in the chordate phylum and its multiple domain organization is probably a chordate innovation. The putative involvement of SCO-spondin in neuron/glia interaction in the course of development is assessed in various cell culture systems. SCO-spondin interferes with several developmental processes, including neuronal survival, neurite extension, neuronal aggregation, and fasciculation. The TSR motifs, and especially the WSGWSSCSVSCG sequence, are most important in these neuronal responses. Integrins and growth factor receptors may cooperate as integrative signals. We discuss the putative involvement of the subcommissural organ/Reissner's fiber complex in developmental events, as a particular extracellular signaling system.

The lengthening of a giant protein: when, how, and why?

Subcommissural organ (SCO)-spondin is a giant glycoprotein of more than 5000 amino acids found in Vertebrata, expressed in the central nervous system and constitutive of Reissner's fiber. For the first time, in situ hybridization performed on zebrafish (Danio rerio) embryos shows that the gene encoding this protein is expressed transitionally in the floor plate, the ventral midline of the neural tube, and later in the diencephalic third ventricle roof, the SCO. The modular organization of the protein in Echinodermata (Strongylocentrotus purpuratus), Urochordata (Ciona savignyi and C. intestinalis), and Vertebrata (Teleostei, Amphibia, Aves and Mammalia) is also described. As the thrombospondin type 1 repeat motifs represent an increasingly large part of the protein during Deuterostomia evolution, the duplication mechanisms leading to this complex organization are examined. The functional significance of the particularly well-preserved arrangement of the series of SCO-spondin repeat motifs and thombospondin type 1 repeats is discussed.

Molecular cloning and early expression of chick embryo SCO-spondin.

SCO-spondin is a multidomain glycoprotein secreted by the subcommissural organ (SCO). It belongs to the thrombospondin type 1 repeat superfamily and has been identified in several vertebrate species. We report the cloning of the chick SCO-spondin ortholog and examine its temporal and spatial expression during early embryogenesis from Hamburger and Hamilton (HH) stage 12 to HH stage 21. Chick SCO-spondin cDNA contains a long open reading frame encoding a predicted protein of 5255 amino acids. Northern blot analysis has revealed SCO-spondin mRNA as a band of about 15 kb. Many conserved domains have been identified, including 27 thrombospondin type 1 repeats, 13 low-density lipoprotein receptor type A domains, one EMI domain (a cysteine-rich domain of extracellular proteins), three von Willebrand factor type D domains, and one cystine knot C-terminal domain. Whole-mount in situ hybridization enabled the first signal of mRNA expression to be detected at HH stage 17, exclusively in a thin area of the prosencephalon roof plate. During the following stages of development, SCO-spondin expression remained restricted to this region. The multidomain structure of SCO-spondin and its early expression suggest that it plays a role in developmental processes in the central nervous system.