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Contamination of soil by heavy metals such as Cd causes a serious negative impact on agricultural production and human health. Thus, improvement of tolerance to Cd is one of the major challenges in plant biotechnology. In the present study, we have generated transgenic Nicotiana tabacum (tobacco) plants overexpressing both serine acetyltransferase (SAT) and cysteine synthase (CS) [O-acetylserine (thiol)-lyase], which are committed in the last two steps of cysteine (Cys) biosynthesis, by crossing the respective single-gene transgenic plants. Two enzymatic activities were high in these two-gene overexpressing plants, and these plants exhibited more resistance to Cd stress than wild-type and single-gene transgenic plants. The two-gene transgenic plants also exhibited a higher production of phytochelatins (PCs) in an inducible manner by the Cd stress. The levels of free non-chelated Cd were lower in the two-gene transgenic plants than the wild-type and single-gene transformants. The levels of Cys and γ-glutamylcysteine (γ-EC) were also increased in the dual transgenic plants, presumably enhancing the metabolic flow of Cys biosynthesis leading to the ultimate synthesis of PCs which detoxify Cd by chelating. These results suggested that the overexpression of two genes, SAT and CS, could be a promising strategy for engineering Cd resistant plants.

Today, many people prefer the simplicity of eating at fast-food restaurants. The prevalence of overweight and obesity thus seems likely to continue to rise in coming decades, and recent evidence has demonstrated that obesity is associated with cancer, infectious diseases, and metabolic syndrome. We hypothesized that obesity induces mechanical changes in the digestive and circulatory organs, which may in turn disrupt homeostasis. This study investigated systemic and local impacts of diet-induced obesity on the immune system, including the mucosal tissues. Mice were administered a high-fat diet (HFD) or normal diet (ND) for 3 weeks, after which plasma and fecal extracts were collected at 6-h intervals. A significant reduction in plasma immunoglobulin (Ig)G and increase in fecal secretory (S-) S-IgA concentrations were observed in HFD-fed mice. In addition, corticosterone levels were significantly higher in the plasma of mice fed HFD when compared with those fed ND, indicating that daily intake of high-fat foods causes physiological stress. Taken together, these results suggest that regular consumption of high-fat foods may negatively impact both systemic and mucosal immune responses.

Information processing in a biological system is more redundant than in a computer system, realizing real‐time processing, eventhough the individual processing speed is low. This paper discusses a neuron electronic model; it is considered the core of biological information processing that has application to engineering problems. The circuit is based on the element which uses a Λ‐shaped transistor, a three‐terminal voltage‐controlled negative‐resistance device, to realize both negative resistance and inductance. It is shown that a hardware neuron model can be constructed by a simple circuit. The existence of a threshold and the generation of action potential are discussed, together with other characteristics of the model. It is then shown that, by improving the Λ‐shaped transistor, a hardware neuron model can be constructed with the self‐organizing function with adjustable threshold. The model is compared with BVP and HH models. A hardware neuron model with K‐conductance characteristics of H‐H model is constructed, followed by the discussion of characteristics such as those for constant‐current stimulation. Through this analysis, it is demonstrated that the proposed model can well simulate the biological neuron, and has the potential to be applied to engineering problems.

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