Expression of vimentin and glial fibrillary acidic protein in central nervous system development of rats

Objective: To investigate the distribution and contents of vimentin(Vim) and glial fibrillary acidic protein(GFAP) immunoreactivities in the central nervous system(CNS)of normal newborn, adult and aged rats.Methods: In this study, thirty healthy and normal Sprague–Dawley rats were simply classified into three groups: Newborn(7 days aged), adult(5 months aged) and aged(24 months aged) rats. Brains and spinal cord were dissected and cut into frozen sections. The expression of Vim and GFAP in CNS were detected by confocal immunofluorescence.Results: In each group, Vim was expressed in all the regions of CNS including the hippocampal, cerebral cortex, the third ventricle and spinal cord, and the expression was highest in neuron-like cell of newborn rats, while Vim was mainly expressed in cell bodies in adult and aged rats. GFAP was expressed in all the regions of CNS including the hippocampal, cerebral cortex, the third ventricle and spinal cord, and the expression was in astrocytes of aged rats. In the third ventricle, Vim was detected in all groups, and only observed in neuron-like cells of newborn. Meanwhile, the GFAP expression showed no significant differences between adult and aged rats in this region. The co-localization of Vim and GFAP were mainly observed in hippocampus and cerebral cortex of newborn,but this co-localization was found in the third ventricle of the rats in all groups.Conclusion: Our data demonstrate for the first time that the expression of Vim and GFAP in the rat's CNS during development. This data may provide a foundation for the further mechanistic studies of these two main intermediate filaments during development of CNS.

硅藻介导下的钙化新途径及其对海洋生物泵的影响

硅藻是海洋中最重要的初级生产者和有机碳输送者,对硅藻驱动下的生物泵过程研究已久,但至今尚未有海洋硅藻物种引发CaCO_(3)沉淀的报道.本研究发现硅藻中肋骨条藻(Skeletonema costatum)在光合作用下能够在远低于无机CaCO_(3)析出所需过饱和度下,从人工/天然海水中诱导出大量文石沉淀;并明确了中肋骨条藻介导钙化新途径的机理,即在生长过程中能在细胞表面富集[CO_(3)^(2-)]和[Ca^(2+)],形成利于CaCO_(3)成核和生长的微环境.硅藻介导下的钙化机制可以解释东海中肋骨条藻在藻华期间观测到的海水总碱度(TA)显著偏离保守混合的现象.新钙化途径建立了硅和钙循环之间的新桥梁,也为更好地理解海洋中碳循环的过程和机制,特别是在未来海洋酸化情景下,提供了颗粒无机碳泵和有机碳泵之间的新联系.

Wastewater alkalinity addition as a novel approach for ocean negative carbon emissions

Anthropogenic CO_(2)emissions have greatly increased atmospheric CO_(2)contributing to global warming and leading to ocean acidification(Figure 1).As reflected in the recent IPCC report,the scientific community’s consensus is that emissions reductions alone are not sufficient or timely enough to avoid a global warming catastrophe.

Stressing over the Complexities of Multiple Stressors in Marine and Estuarine Systems

Aquatic ecosystems are increasingly threatened by multiple human-induced stressors associated with climate and anthropogenic changes,including warming,nutrient pollution,harmful algal blooms,hypoxia,and changes in CO_(2) and pH.These stressors may affect systems additively and synergistically but may also counteract each other.The resultant ecosystem changes occur rapidly,affecting both biotic and abiotic components and their interactions.Moreover,the complexity of interactions increases as one ascends the food web due to differing sensitivities and exposures among life stages and associated species interactions,such as competition and predation.There is also a need to further understand nontraditional food web interactions,such as mixotrophy,which is the ability to combine photosynthesis and feeding by a single organism.The complexity of these interactions and nontraditional food webs presents challenges to ecosystem modeling and management.Developing ecological models to understand multistressor effects is further challenged by the lack of sufficient data on the effects of interactive stressors across different trophic levels and the substantial variability in climate changes on regional scales.To obtain data on a broad suite of interactions,a nested set of experiments can be employed.Modular,coupled,multitrophic level models will provide the flexibility to explore the additive,amplified,propagated,antagonistic,and/or reduced effects that can emerge from the interactions of multiple stressors.Here,the stressors associated with eutrophication and climate change are reviewed,and then example systems from around the world are used to illustrate their complexity and how model scenarios can be used to examine potential future changes.

Unveiling the secrets of diatom-mediated calcification:Implications for the biological pump

Siliceous diatoms are one of the most prominent actors in the oceans,and they account for approximately 40%of the primary production and particulate organic carbon export flux.It is believed that changes in carbon flux caused by variations in diatom distribution can lead to significant climate shifts.Although the fundamental pathways of diatom-driven carbon sequestration have long been established,there are no reports of CaCO_(3) precipitation induced by marine diatom species.This manuscript introduces novel details regarding the enhancement of aragonite precipitation during photosynthesis in Skeletonema costatum in both artificial and natural seawater.Through direct measurements of cell surfaces via a pH microelectrode and zeta potential analyzer,it was determined that the diatom-mediated promotion of CaCO_(3) precipitation is achieved through the creation of specific microenvironments with concentrated[CO_(3)^(2-)]and[Ca^(2+)]and/or the dehydrating effect of adsorbed Ca^(2+).Based on this mechanism,it is highly plausible that diatom-mediated calcification could occur in the oceans,an assertion that was supported by the significant deviation of total alkalinity(TA)from the conservative TA-salinity mixing line during a Skeletonema costatum bloom in the East China Sea and other similar occurrences.The newly discovered calcification pathway establishes a link between particulate inorganic and organic carbon flux and thus helps in the reassessment of marine carbon export fluxes and CO_(2) sequestration efficiency.This discovery may have important ramifications for assessing marine carbon cycling and predicting the potential effects of future ocean acidification.