The liver plays a key role in removing harmful chemicals from the body and is therefore often the first tissue to suffer potentially adverse consequences. To protect public health it is necessary to quantitatively estimate the risk of long-term low dose exposure to environmental pollutants. Animal testing is the primary tool for extrapolating human risk but it is fraught with uncertainty, necessitating novel alternative approaches. Our goal is to integrate in vitro liver experiments with agent-based cellular models to simulate a spatially extended hepatic lobule. Here we describe a graphical model of the sinusoidal network that efficiently simulates portal to centrilobular mass transfer in the hepatic lobule. We analyzed the effects of vascular topology and metabolism on the cell-level distribution following oral exposure to chemicals. The spatial distribution of metabolically inactive chemicals was similar across different vascular networks and a baseline well-mixed compartment. When chemicals were rapidly metabolized, concentration heterogeneity of the parent compound increased across the vascular network. As a result, our spatially extended lobule generated greater variability in dose-dependent cellular responses, in this case apoptosis, than were observed in the classical well-mixed liver or in a parallel tubes model. The mass-balanced graphical approach to modeling the hepatic lobule is computationally efficient for simulating long-term exposure, modular for incorporating complex cellular interactions, and flexible for dealing with evolving tissues. 相似文献
Addition of a mixture of EGF + insulin to quiescent cell cultures synergistically stimulates the cells to reinitiate DNA synthesis and cell division. We have previously demonstrated that this mixture rapidly increases ATP turnover in quiescent cells. The present work shows that each of the two growth factors, EGF and insulin, when added separately to quiescent cells was able to stimulate the phosphorylation of the organic acid-soluble compounds (Po) pool and ATP turnover. The stimulation of ATP turnover was closely correlated with the increase in phosphorylation of the Po pool which suggests that Po labelling reflects the ATP turnover. In many experiments, the synergy between the two growth factors on the early increase in phosphorylation of the Po pool was clearly shown. Doubling the concentration of EGF (12-24 ng/ml) or insulin (50-100 ng/ml) did not increase early stimulation of phosphorylation of the Po pool, whereas simultaneous addition of the two growth factors induced a greater stimulation than that of each growth factor separately added. The augmentation in Po labelling after addition of EGF or insulin alone was transient. The synergistic effect of the two growth factors was more significant when determined 150 or 300 min after growth-factor addition. In our experimental conditions, each of the two growth factors, EGF and insulin, was able to induce a stimulation of DNA synthesis. However, the best stimulatory effect was observed with the mixture of the two which synergistically increased DNA synthesis determined between 6 and 24 h after growth-factor addition. The comparison between DNA replication and Po labelling suggests a correlation between the increase in DNA replication and in the total ATP synthesized in the first 5 h after cell stimulation by growth factors added separately or in combination. 相似文献
The penicillin derivative amoxicillin (AMX) plays an important role in treating various types of infections caused by bacteria. However, excessive use of AMX may have negative health effects. Therefore, it is of utmost importance to detect and quantify the AMX in pharmaceutical drugs, biological fluids, and environmental samples with high sensitivity. Therefore, this review article provides valuable and up-to-date information on nanostructured material-based optical and electrochemical sensors to detect AMX in various biological and chemical samples. The role of using different nanostructured materials on the performance of important optical sensors such as colorimetric sensors, fluorescence sensors, surface-enhanced Raman scattering sensors, chemiluminescence/electroluminescence sensors, optical immunosensors, optical fibre-based sensors, and several important electrochemical sensors based on different electrode types have been discussed. Moreover, nanocomposites, polymer, and MXenes-based electrochemical sensors have also been discussed, in which such materials are being used to further enhance the sensitivity of these sensors. Furthermore, nanocomposite-based photo-electrochemical sensors and the market availability of biosensors including AMX have also been discussed briefly. Finally, the conclusion, challenges, and future perspectives of the above-mentioned sensing techniques for AMX detection are presented. 相似文献
Low-temperature and high humidity are typical environmental factors in the plastic tunnel and solar greenhouse during the cold season that restricts plant growth and development. Herein, we investigated the impact of different combinations of low-temperature and high humidity (day/night: T1 15/10 °C?+?95%, T2 12/8 °C?+?95%, and T3 9/5 °C?+?95%) along with a control (CK 25/18 °C?+?80%) on cucumber cultivars viz: Zhongnong37 (ZN37: resistant) and Shuyanbailv (SYB: sensitive). The low-temperature and high humidity stresses increased electrolyte leakage (EL), malondialdehyde (MDA), hydrogen peroxide (H2O2) and intercellular concentration of carbon dioxide (Ci), and reduced morphological indices, relative water content (RWC), net photosynthesis rate (Pn), stomatal conductance (Gs), transpiration rate (E) and leaf pigments in both cultivars as compared to control (CK). Superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) were decreased in cv. SYB under stress conditions as compared to cv. ZN37. Low-temperature and high humidity treatments showed an increase in proline and soluble protein content in cv. ZN37 as compared to cv. SYB. Abscisic acid (ABA) and jasmonic acid (JA) were augmented while indole-3-acetic acid (IAA), zeatin (ZT), zeatin riboside (ZR), and gibberellic acid (GA) were decreased in both cultivars. Under T3 (9/5 °C?+?95%), Pn, protoporphyrin, and ZT were extremely decreased by 71.3%, 74.3%, and 82.4%, respectively, in cv. SYB compared to control. Moreover, principal component analysis (PCA) based on physiochemical traits confirmed that cv. ZN37 had the strongest correlation with antioxidant enzymes, proline, and soluble protein content than cv. SYB under low-temperature and high humidity treatments. Our results suggest that a stress-tolerant cultivar mitigates stress damage in cucumber transplants by regulating photosynthetic efficiency, antioxidant capacity and hormonal profile when compared to a stress-sensitive cultivar.
Ongoing intensification and fragmentation of European agricultural landscapes dramatically reduce biodiversity and associated functions. Enhancing perennial noncrop areas holds great potential to support ecosystem services such as ant‐mediated pest control.
To study the potential of newly established grassland strips to enhance ant diversity and associated functions, we used hand collection data and predation experiments to investigate differences in (a) ant community composition and (b) biocontrol‐related functional traits, and (c) natural pest control across habitats in cereal fields, old grasslands, and new grassland transects of three years of age.
Ant species diversity was similar between new and old grasslands, but significantly higher in new grasslands than in surrounding cereal fields. Contrary, ant community composition of new grasslands was more similar to cereal fields and distinct from the species pool of old grasslands. The functional trait space covered by the ant communities showed the same distribution between old and new grasslands. Pest control did not differ significantly between habitat types and therefore could not be linked to the prevalence of functional ant traits related to biocontrol services in new grasslands.
Our findings not only show trends of convergence between old and new grasslands, but also indicate that enhancing ant diversity through new grasslands takes longer than three years to provide comparable biodiversity and functionality.
Synthesis and applications: Newly established grasslands can increase ant species richness and abundance and provide a consistent amount of biocontrol services in agroecosystems. However, three years after their establishment, new grasslands were still dominated by common agrobiont ant species and lacked habitat specialists present in old grasslands, which require a constant supply of food resources and long colony establishment times. New grasslands represent a promising measure for enhancing agricultural landscapes but must be preserved in the longer term to promote biodiversity and resilience of associated ecosystem services.
We previously shown a rapid increase in ATP turnover after addition of epidermal growth factor and insulin to quiescent 3T3 cell cultures. Here, the relationship between this increase in ATP turnover and the activation by growth factors of Na+/H+ and Na+/K+ exchange systems was studied. Our results show that alkalinization of the medium enhances ATP turnover but they do not support the assumption that stimulation by growth factors of the Na+/H+ exchange induces an increase in ATP turnover since this increase was not inhibited by amiloride. Conversely, when ATP synthesis was abolished, the increase, in intracellular pH, by growth factors, was significantly decreased. 相似文献