Although lung injury including fibrosis is a well‐documented side effect of lung irradiation, the mechanisms underlying its pathology are poorly understood. X‐rays are known to cause apoptosis in the alveolar epithelial cells of irradiated lungs, which results in fibrosis due to the proliferation and differentiation of fibroblasts and the deposition of collagen. Apoptosis and BH3‐only pro‐apoptotic proteins have been implicated in the pathogenesis of pulmonary fibrosis. Recently, we have established a clinically analogous experimental model that reflects focal high‐dose irradiation of the ipsilateral lung. The goal of this study was to elucidate the mechanism underlying radiation‐induced lung injury based on this model. A radiation dose of 90 Gy was focally delivered to the left lung of C57BL/6 mice for 14 days. About 9 days after irradiation, the mice began to show increased levels of the pro‐apoptotic protein Noxa in the irradiated lung alongside increased apoptosis and fibrosis. Suppression of Noxa expression by small interfering RNA protected cells from radiation‐induced cell death and decreased expression of fibrogenic markers. Furthermore, we showed that reactive oxygen species participate in Noxa‐mediated, radiation‐induced cell death. Taken together, our results show that Noxa is involved in X‐ray‐induced lung injury. 相似文献
To explore the adsorption mechanism of NO, NH3, N2 on a carbon surface, and the effect of basic and acidic functional groups, density functional theory was employed to investigate the interactions between these molecules and carbon surfaces. Molecular electrostatic potential, Mulliken population analyses, reduced density gradient, and Mayer bond order analyses were used to clarify the adsorption mechanism. The results indicate that van der Waals interactions are responsible for N2 physisorption, and N2 is the least likely to adsorb on a carbon surface. Modification of carbon materials to decorate basic or acidic functional groups could enhance the NH3 physisorption because of hydrogen bonding or electrostatic interactions, however, NO physisorption on a carbon surface is poor. Zig-zag sites are more reactive than armchair sites when these gas molecules absorb on the edge sites of carbon surface.
Chinese pollination-constant and non-astringent persimmon (C-PCNA) has important application values in the genetic improvement of PCNA for its trait of natural deastringency controlled by a single dominant gene. However, the key genes and the regulatory networks are still not fully understood. The process of C-PCNA natural deastringency may be associated with the acetaldehyde-mediated coagulation of soluble tannins, but the functions of ALDH2 genes related to the metabolism of acetaldehyde are not clear. In this work, three types of persimmon cultivars, ‘Eshi 1’ and ‘Luotian Tianshi’ (C-PCNA type), ‘Youhou’ (J-PCNA type), and ‘Mopanshi’ (non-PCNA type), were sampled. Two members of ALDH2 family genes, DkALDH2a and DkALDH2b, were isolated from ‘Eshi 1’ persimmon fruit. Gene expression patterns indicated that they may be involved in “coagulation effect”, which leads to natural deastringency in C-PCNA persimmon fruit. Transient expression in ‘Eshi 1’ leaves further demonstrated that their expression can reduce the consumption of soluble tannins and inhibit the astringency removal process. Therefore, DkALDH2a and DkALDH2b are negatively correlated with natural deastringency in C-PCNA persimmon. 相似文献
Enzyme immobilization is believed to provide an excellent base for increasing environmental tolerance of enzyme and considerable period of time. In this work, a kind of nonporous silica nanoparticles functionalized with amino group was synthesized to immobilize proline-specific endoprotease (PSEP). PSEP is known to specifically cleave peptides (or esters) at the carboxyl side of proline, thus can prevent the formation of haze and prolong the shelf life of beer. After immobilization, the environmental tolerance (temperature and pH, respectively) was obviously improved, and the immobilized enzyme can retain above 90 % of its original activity after 6 uses. Moreover, the immobilized enzyme can effectively prevent the formation of chill-haze using fresh beer fermentation liquid. 相似文献
B‐cell maturation antigen (BCMA) fused at the C‐terminus to the Fc portion of human IgG1 (BCMA‐Fc) blocks B‐cell activating factor (BAFF) and proliferation‐inducing ligand (APRIL)‐mediated B‐cell activation, leading to immune disorders. The fusion protein has been cloned and produced by several engineering cell lines. To reduce cost and enhance production, we attempted to express recombinant human BCMA‐Fc (rhBCMA‐Fc) in Pichia pastoris under the control of the AOX1 methanol‐inducible promoter. To produce the target protein with uniform molecular weight and reduced immunogenicity, we mutated two predicted N‐linked glycosylation sites. The secretory yield was improved by codon optimization of the target gene sequence. After fed‐batch fermentation under optimized conditions, the highest yield (207 mg/L) of rhBCMA‐Fc was obtained with high productivity (3.45 mg/L/h). The purified functional rhBCMA‐Fc possessed high‐binding affinity to APRIL and dose‐dependent inhibition of APRIL‐induced proliferative activity in vitro through three‐step purification. Thus, this yeast‐derived expression method could be a low‐cost and effective alternative to the production of rhBCMA‐Fc in mammalian cell lines. 相似文献
The aim of this study was to determine the impact of increased copper contents on selected physiological processes in oneyear-old Pinus sylvestris L. needles from a former German timber storage area in Warcino Forest District, a subject to an environmental quality survey. Samples were collected from the area with the high copper content in the soil. The control area was a nearby pine tree stand showing unimpeded growth. The significant growth inhibition was found in dwarf shoots and whole needles, increased water content, and reduced dry mass were also observed. The chlorophyll content was lowered, while 20% higher electrolyte leakage was found. Chlorophyll a fluorescence indicated only higher values of the nonphotochemical quenching in P. sylvestris from the Cu-site. Significant differences were shown in the rate of gas exchange measured by changes in carbon dioxide or oxygen concentration. The intensity of photosynthesis in needles of P. sylvestris from the Cu-site measured by CO2 uptake was considerably higher than that of oxygen production. The rate of respiration in the needles from the Cu-site measured by the amount of released CO2 was higher only by 15%, while according to O2 consumed, the rate increased by 30% in relation to the control. Our results suggest that the copper accumulation in P. sylvestris needles affected the morphology and physiology of the studied organs. 相似文献
Mammary gland development is critically dependent on the interactions between its stromal and epithelial compartments. In this study, we established a co-culture of bovine mammary epithelial Mac-T cells and murine preadipocyte 3T3-L1 cells. Mac-T cells were co-cultured with 3T3-L1 cells for four days and production of milk proteins was induced for three days. After seven days of co-culturing, the number of alveolar-like colonies in the presence of 3T3-L1 cells was significantly higher than that in control group. Expression levels of αS1-casein and β-casein mRNAs were significantlyincreased by co-culturing with 3T3-L1 cells. In addition, casein protein production was significantly higher in the co-culture of Mac-T cells with 3T3-L1 cells than in control Mac-T cells. Substances that induced casein production in Mac-T cells also stimulated adipogenesis in 3T3-L1 cells. We suggest that a co-culture system of bovine mammary epithelial cells and preadipocyte cells is an efficient method for in vitro milk protein production. 相似文献
Migrating long distances requires time and energy, and may interact with an individual's performance during breeding. These seasonal interactions in migratory animals are best described in populations with disjunct nonbreeding distributions. The black‐tailed godwit (Limosa limosa limosa), which breeds in agricultural grasslands in Western Europe, has such a disjunct nonbreeding distribution: The majority spend the nonbreeding season in West Africa, while a growing number winters north of the Sahara on the Iberian Peninsula. To test whether crossing the Sahara has an effect on breeding season phenology and reproductive parameters, we examined differences in the timing of arrival, breeding habitat quality, lay date, egg volume, and daily nest survival among godwits (154 females and 157 males), individually marked in a breeding area in the Netherlands for which wintering destination was known on the basis of resightings. We also examined whether individual repeatability in arrival date differed between birds wintering north or south of the Sahara. Contrary to expectation, godwits wintering south of the Sahara arrived two days earlier and initiated their clutch six days earlier than godwits wintering north of the Sahara. Arrival date was equally repeatable for both groups, and egg volume larger in birds wintering north of the Sahara. Despite these differences, we found no association between wintering location and the quality of breeding habitat or nest survival. This suggests that the crossing of an important ecological barrier and doubling of the migration distance, twice a year, do not have clear negative reproductive consequences for some long‐distance migrants. 相似文献