Birkhoff's variety theorem for relative algebraic theories

An algebraic theory, sometimes called an equational theory, is a theory defined by finitary operations and equations, such as the theories of groups and of rings. It is well known that algebraic theories are equivalent to finitary monads on $\mathbf{Set}$. In this paper, we generalize this phenomenon to locally finitely presentable categories using partial Horn logic. For each locally finitely presentable category $\mathscr{A}$, we define an "algebraic concept" relative to $\mathscr{A}$, which will be called an $\mathscr{A}$-relative algebraic theory, and show that $\mathscr{A}$-relative algebraic theories are equivalent to finitary monads on $\mathscr{A}$. Finally, we generalize Birkhoff's variety theorem for classical algebraic theories to our relative algebraic theories.Comment: 34 page

Filtered colimit elimination from Birkhoff's variety theorem

Birkhoff's variety theorem, a fundamental theorem of universal algebra, asserts that a subclass of a given algebra is definable by equations if and only if it satisfies specific closure properties. In a generalized version of this theorem, closure under filtered colimits is required. However, in some special cases, such as finite-sorted equational theories and ordered algebraic theories, the theorem holds without assuming closure under filtered colimits. We call this phenomenon "filtered colimit elimination," and study a sufficient condition for it. We show that if a locally finitely presentable category $\mathscr{A}$ satisfies a noetherian-like condition, then filtered colimit elimination holds in the generalized Birkhoff's theorem for algebras relative to $\mathscr{A}$.Comment: 22 page

Impacts of Subchronic and Mild Social Defeat Stress on Plasma Putrefactive Metabolites and Cardiovascular Structure in Male Mice

Psychosocial stress precipitates mental illnesses, such as depression, and increases the risk of other health problems, including cardiovascular diseases. In this study, we observed the effects of psychosocial stress on the histopathological features of systemic organs and tissues in a mouse psychosocial stress model, namely the subchronic and mild social defeat stress (sCSDS) model. There were several pathological findings in the tissues of both sCSDS and control mice. Mild fibrosis of the heart was observed in sCSDS mice but not in control mice. Extramedullary hematopoiesis in the spleen and hemorrhage in the lungs were observed in both the control and sCSDS mice. Focal necrosis of the liver was seen only in control mice. Furthermore, putrefactive substances in the blood plasma were analyzed because these metabolites originating from intestinal fermentation might be linked to heart fibrosis. Among them, plasma p-cresyl glucuronide and p-cresyl sulfate concentrations significantly increased owing to subchronic social defeat stress, which might influence cardiac fibrosis in sCSDS mice. In conclusion, several pathological features such as increased cardiac fibrosis and elevated plasma putrefactive substances were found in sCSDS mice. Thus, sCSDS mice are a potential model for elucidating the pathophysiology of psychosocial stress and heart failure

6-Shogaol, an Active Component of Ginger, Inhibits p300 Histone Acetyltransferase Activity and Attenuates the Development of Pressure-Overload-Induced Heart Failure

Hypertrophic stress-induced cardiac remodeling is a compensatory mechanism associated with cardiomyocyte hypertrophy and cardiac fibrosis. Continuation of this response eventually leads to heart failure. The histone acetyltransferase p300 plays an important role in the development of heart failure, and may be a target for heart failure therapy. The phenolic phytochemical 6-shogaol, a pungent component of raw ginger, has various bioactive effects; however, its effect on cardiovascular diseases has not been investigated. One micromolar of 6-shogaol suppressed phenylephrine (PE)-induced increases in cardiomyocyte hypertrophy in rat primary cultured cardiomyocytes. In rat primary cultured cardiac fibroblasts, 6-shogaol suppressed transforming growth factor-beta (TGF-β)-induced increases in L-proline incorporation. It also blocked PE- and TGF-β-induced increases in histone H3K9 acetylation in the same cells and in vitro. An in vitro p300-HAT assay revealed that 6-shogaol suppressed histone acetylation. The mice underwent transverse aortic constriction (TAC) surgery, and were administered 0.2 or 1 mg/kg of 6-shogaol daily for 8 weeks. 6-shogaol prevented TAC-induced systolic dysfunction and cardiac hypertrophy in a dose-dependent manner. Furthermore, it also significantly inhibited TAC-induced increases in histone H3K9 acetylation. These results suggest that 6-shogaol may ameliorate heart failure through a variety of mechanisms, including the inhibition of p300-HAT activity

A chemical probe that labels human pluripotent stem cells.

A small-molecule fluorescent probe specific for human pluripotent stem cells would serve as a useful tool for basic cell biology research and stem cell therapy. Screening of fluorescent chemical libraries with human induced pluripotent stem cells (iPSCs) and subsequent evaluation of hit molecules identified a fluorescent compound (Kyoto probe 1 [KP-1]) that selectively labels human pluripotent stem cells. Our analyses indicated that the selectivity results primarily from a distinct expression pattern of ABC transporters in human pluripotent stem cells and from the transporter selectivity of KP-1. Expression of ABCB1 (MDR1) and ABCG2 (BCRP), both of which cause the efflux of KP-1, is repressed in human pluripotent stem cells. Although KP-1, like other pluripotent markers, is not absolutely specific for pluripotent stem cells, the identified chemical probe may be used in conjunction with other reagents

A Chemical Probe that Labels Human Pluripotent Stem Cells

A small-molecule fluorescent probe specific for human pluripotent stem cells would serve as a useful tool for basic cell biology research and stem cell therapy. Screening of fluorescent chemical libraries with human induced pluripotent stem cells (iPSCs) and subsequent evaluation of hit molecules identified a fluorescent compound (Kyoto probe 1 [KP-1]) that selectively labels human pluripotent stem cells. Our analyses indicated that the selectivity results primarily from a distinct expression pattern of ABC transporters in human pluripotent stem cells and from the transporter selectivity of KP-1. Expression of ABCB1 (MDR1) and ABCG2 (BCRP), both of which cause the efflux of KP-1, is repressed in human pluripotent stem cells. Although KP-1, like other pluripotent markers, is not absolutely specific for pluripotent stem cells, the identified chemical probe may be used in conjunction with other reagents.1125sciescopu

CO2 Diffusion Inside Photosynthetic Organs

In the present chapter, we review the current state-of-the-art of knowledge on mesophyll (internal) CO2 diffusion conductance of photosynthetic tissues (for simplification, gm). We show that, despite concerns regarding the methodological approaches currently used for its estimation, a large and consistent body of evidence has accumulated showing that gm is finite and significantly limiting for photosynthesis, as well as being highly variable among photosynthetic organisms and in response to environmental changes. Part of this variation results from different anatomies of the photosynthetic tissues, with a particularly strong influence of chloroplast distribution and cell wall thickness. Besides these, it appears that a biochemical modulation of gm also occurs, likely involving aquaporins and, possibly, carbonic anhydrases and other metabolic components.Further efforts are needed in the near future to improve CO2 diffusion models, both for the estimation of gm and for the precise physiological understanding of the CO2 assimilation process in different plants, as well as to increase our knowledge of the mechanistic base for gm and its regulation