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关键词： 本科生物化学与分子生物学实验   实验教学内容   实验方法   实验教学管理   实验室开放  

摘要： 生命科学作为一门以实验为基础的自然科学,本科实验教学也必然是高校培养生物科技人才的重要教学内容之一。生物化学与分子生物学是生命科学的基础,是自然科学中发展最迅速和最具活力的前沿领域,因此生物化学与分子生物学实验教学也是生物科技人才培养的重要组成部分。随着生物化学与分子生物学研究技术的不断发展,对相关本科实验教学也提出了更高要求。同时,现代社会“以人为本”的理念也深入人心,因此在教学中注重学生专业能力提升的同时,对环境的保护和师生的人身安全也更加关注。基于这两方面的要求,实验室近年来在生物化学与分子生物学实验教学内容和实验方法的持续改进方面也进行了一些探索,以适应社会发展和生命科学技术发展的需要。

关键词： 高职生物化学   营养教育   融入  

摘要： 生物化学教学的重点在于引导学生凭借生物现象提高学习兴趣,为后续生物化学学习夯实基础.在中学教学 过程中,生物化学课程的重点在于简单学习生物化学基础知识,而高职时期,需要更为深入地分析相关内容,凡是与之 相关的都可以将其融入到生物化学课堂中来,这就要求教师从现实情况出发分析高职生物化学课堂中营养教育的融 入对策.

关键词： Drought stress   Fatty acids profile   Gas exchange   Oxidative stress   Portulaca oleracea L.   Salicylic acid  

摘要： Purslane (Portulaca oleracea L.) is a plant with a long history in cooking and folk medicine that has been distributed worldwide. In the present study, purslane was used as a model plant to investigate the effect of foliar application of salicylic acid (SA) on plant tolerance to drought stress. The effects of SA foliar spray (0, 0.5 and 1 mM) on physiological and biochemical responses of purslane seedlings under drought stress (90, 60 and 30% field capacity) were investigated. The results showed that drought stress decreased the contents of photosynthetic pigments, parameters of gas exchanges, proline, soluble sugars, total phenolic, flavonoids, growth, and biomass production. However, SA improved photosynthetic pigments, gas exchanges, compatible solutes and secondary metabolites and thereby increased purslane growth and biomass production. Drought stress also induced oxidative stress (H2O2 and MDA) in purslane seedlings; however, SA reduced the drought-induced oxidative stress by regulating the activity of antioxidant enzymes. Drought stress increased the content of palmitic and arachidonic acid and decreased unsaturated fatty acids (oleic, linoleic and linolenic acid), stearic and behenic acid in the leaves of purslane. However, SA improved the fatty acids content under drought stress. These results indicate that foliar application of SA improved the adaptation and tolerance of the purslane plant to drought stress by improving gas exchange, increasing the accumulation of secondary metabolites and compatible solutes, improving the antioxidant defence system and regulating the fatty acids profile of membrane lipid.

关键词： ATR   Checkpoint   BRCT   DNA damage   Scaffold  

摘要： TOPBP1 is an important scaffold protein that helps orchestrate the cellular response to DNA damage. Although it has been previously appreciated that TOPBP1 can form oligomers, how this occurs and the functional consequences for oligomerization were not yet known. Here, we use protein binding assays and other biochemical techniques to study how TOPBP1 self associates. TOPBP1 contains 9 copies of the BRCT domain, and we report that a subset of these BRCT domains interact with one another to drive oligomerization. An intact BRCT 2 domain is required for TOPBP1 oligomerization and we find that the BRCT1&2 region of TOPBP1 interacts with itself and with the BRCT4&5 pair. RAD9 and RHINO are two heterologous binding partners for TOPBP1's BRCT 1&2 domains, and we show that binding of these partners does not come at the expense of TOPBP1 oligomerization. Furthermore, we show that a TOPBP1 oligomer can simultaneously interact with both RAD9 and RHINO. Lastly, we find that the oligomeric state necessary for TOPBP1 to activate the ATR protein kinase is likely to be a tetramer.

关键词： Barley   Antioxidative enzymes   Chromium uptake   Chlorophyll   Multivariate statistical techniques  

摘要： The present study aims at the amelioration of chromium Cr(VI) toxicity using ethylenediaminetetraacetic acid (EDTA), and to understand the interactive effects of Cr(VI) and EDTA with respect to seedling growth, lipid peroxidation as assessed from malondialdehyde, pigments and antioxidative enzymes in Hordeum vulgare L. Following multivariate statistical techniques were used to study binary interactions between Cr(VI) and EDTA: 2-way ANOVA, Tukey's multiple comparison test, multiple regression with interaction between Cr an EDTA, beta coefficients, path analysis and non-metric multidimensional scaling (NMDS). The present study revealed that the EDTA decreases lipid peroxidation induced by Cr(VI) and ameliorates the antioxidative defence system and pigment constitution of seedlings grown in Cr(VI) containing media. EDTA-Cr(VI) interaction decreased the Cr content in the seedlings which may be attributed to the chelating effect of EDTA. The root and shoot bioconcentration factors, the ratio of Cr content in the plant to that in the medium, were decreased by addition of EDTA to Cr(VI), indicating a decrease in the uptake of Cr by the seedlings from the medium. NMDS revealed that the ranking of the studied parameters is maintained by ordination on two axes. The study established that EDTA is antagonistic to Cr(VI) induced biochemical toxicity, and improves the antioxidative defence system, increases the chlorophyll content, and decreases Cr uptake in barley seedlings.

关键词： Verbenaceae   Medicinal plant   LED lighting   Ventilated test tubes  

摘要： Lippia grata Schauer is a Brazilian savanna plant that belongs to the Verbenaceae family. Its importance in folk medicine, combined with threats to its natural habitat, gave rise to the necessity to carry out studies involving large-scale propagation. Unlike other species of the same genus, L. grata has shown high rates of hyperhydricity, which reduces survival during acclimatization. The present study aimed to define an efficient protocol that minimizes hyperhydricity. Young cuttings containing nodal segments were cultivated in Murashige-Skoog medium. The culture test tubes were totally sealed with aluminum foil (non-ventilated) or partially sealed (ventilated) with aluminum foil containing one hole. The cultures were maintained in a growth room exposed to four light treatments for 45 days: two combinations of red and blue light-emitting diodes (LED) with red: blue light ratios of 5:1 and 1:1, white-LED, and fluorescent lamps. Non-ventilation under fluorescent lamps represent traditional conditions of tissue culture. The lowest hyperhydricity rates in plants were found in the partially sealed culture test tubes. The combination of partial sealing with red/blue LED at a 1:1 light ratio resulted in 26% hyperhydric leaves in contrast to 87% under traditional conditions. Higher contents of photosynthetic pigments, namely chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids were found in plants under partially sealed test tubes under white-LED illumination, reaching 1.24, 0.56, 1.79, and 412.94 mg g (1) FM, respectively. In addition to uniformity in cell morphology of the various tissues, plants cultivated under partial sealing showed higher content of total soluble carbohydrates and sucrose, i.e., 487.49 and 192.74 mg g (1) FM, respectively. These results demonstrate that micropropagation systems with higher light intensity and quality (wavelengths), combined with a facilitated gas exchange between culture and laboratory air, were efficient in preventing hy

关键词： Ecotoxicology   Aquatic toxicology   Endocrine disruption   Intersex   Biomarkers   Ecotoxicogenomics  

摘要： Adverse reproductive effects associated with gonadal intersex among freshwater fish could hold considerable implications for population sustainability. Presence of testicular oocytes (TO) is the most common form of intersex and is widespread among centrarchids (sunfishes) of North America and other freshwater teleosts. Placing TO within the toxicological context of adverse outcome pathways (AOPs) to assess ecological risk is a priority for ecotoxicologists due to the association of TO with harmful chemical exposure and adverse reproductive effects in some cases. However, key event relationships between EDC exposure, incidence of TO, and apical outcomes have yet to be fully elucidated - in part due to a lack of knowledge of relationships between intersex gonad physiology and fish health. Understanding the physiological status of intersex fish is critical to assess ecological risk, understand mechanisms of induction, and to establish biomarkers of intersex in fish. In the present study, features of gonad metabolite profiles associated with TO in largemouth bass (LMB, Micropterus salmoides) from an impoundment in Georgia (USA) were determined using GC-MS-based metabolomics. Clinical blood biochemical screens were used to evaluate markers of fish health associated with TO. Results suggest that physiological changes in energy expenditure as well as relatively 'feminized' gonad lipid and protein metabolism may be related to the occurrence of TO in male LMB, and highlight the need to understand relationships between intersex and physical stressors such as elevated temperature and hypoxia. These results provide novel insight to AOPs associated with TO and identify candidate analytes for biomarker discovery.

关键词： Arugula   Lettuce   Selenium tolerance   Antioxidants   Sulfur   Se accumulator and non-accumulator  

摘要： Selenium (Se) biofortification in crops provides a valuable strategy to enhance human Se intake. However, crops vary greatly with their capacity in tolerating and metabolizing/accumulating Se, and the basis underlying such variations remains to be fully understood. Here, we compared the effects of Se and its analog S treatments on plant growth and biochemical responses between a Se accumulator (arugula) and a non-accumulator (lettuce). Arugula exhibited an increased biomass production in comparison with untreated controls at a higher selenate concentration than lettuce (20 mu M vs. 10 mu M Na2SeO4), showing better tolerance to Se. Arugula accumulated 3-folds more Se and S than lettuce plants under the same treatments. However, the Se/S assimilation as assessed by ATP sulfurylase and O-acetylserine (thiol)lyase activities was comparable between arugula and lettuce plants. Approximately 4-fold higher levels of Se in proteins under the same doses of Se treatments were observed in arugula than in lettuce, indicating that Se accumulators have better tolerance to selenoamino acids in proteins. Noticeably, arugula showed 6-fold higher ascorbate peroxidase activity and produced over 5-fold more glutathione and non-protein thiols than lettuce plants, which suggest critical roles of antioxidants in Se tolerance. Taken together, our results show that the elevated Se tolerance of arugula compared to lettuce is most likely due to an efficient antioxidant defense system. This study provides further insights into our understanding of the difference in tolerating and metabolizing/accumulating Se between Se accumulators and non-accumulators.