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ObjectiveTo provide a reference for food safety risk assessment and safety assurance for the Winter Olympics and Beijing residents， the exposure level and possible health risks of cadmium （Cd） in main foods in the surrounding areas of the 2022 Beijing Winter Olympics were evaluated. MethodsBased on the hazard assessment and limit standard analysis of cadmium， the point assessment method was used to assess the dietary exposure risk of cadmium. The 2019 to 2020 on-site sampling survey data of an urban area of Beijing and Zhangjiakou Chongli area and the 2018 Beijing main food consumption survey data were used in this pre-assessment. ResultsThe cadmium provisional tolerated monthly intake （PTMI） established by joint FAO/WHO Expert Committee on Food Additives （JECFA） was 25 μg/kg·BW. The overall average content of cadmium in various foods was 0.010 6 mg/kg， and the overall rate of exceeding the standard was 0.47%. The average exposure of Beijing residents to cadmium through the main food was 5.92 µg/（kg·BW·m）， accounting for 23.66% of the JECFA-recommended provisional tolerable monthly intake （PTMI） of 25 μg/kg·BW. In addition， cereals and vegetable foods were the main sources of dietary cadmium exposure. According to the current limit of cadmium （LOC） in GB 2762—2017 National Food Safety Standards Limits of contaminants in food， except for these two categories of food， the theoretical exposure to cadmium in the rest of the food did not exceed the PTMI. The estimated LOC for vegetables， grains and cereals is 0.172 and 0.199 mg/kg， both of which were less than the maximum limit value stipulated by the national standard. ConclusionThe main food cadmium exposure of Winter Olympics and Beijing residents is generally at a safe level， and the health risk is relatively low.

L-theanine, a non-protein amino acid naturally occurring in tea leaves, is recognized for its antioxidant, anti-inflammatory, and neuroprotective properties. Despite its known benefits, the mechanisms by which L-theanine influences lifespan extension remain poorly understood. This study investigated the effects of L-theanine on the lifespan of Caenorhabditis elegans and explored the underlying mechanisms. Our findings indicate that L-theanine significantly diminishes the accumulation of advanced glycation end products (AGEs), which are biomarkers closely linked to aging and age-related diseases. Through an AGE-level analysis, we observed that L-theanine, when administered during early adulthood, notably extended the lifespan of Caenorhabditis elegans under both normal and high-glucose-induced stress conditions. L-theanine enhanced the lifespan under typical conditions and provided protective effects against high-glucose-induced stress. A further analysis demonstrated that L-theanine extends the lifespan of Caenorhabditis elegans by modulating the DAF-2/DAF-16 insulin-like signaling pathway and reducing the accumulation of advanced glycation end products (AGEs). In summary, this study identified L-theanine as a potential anti-aging intervention that extends the lifespan by reducing AGE accumulation and regulating insulin-like signaling pathways. These findings provide new insights for developing anti-aging strategies and lay the groundwork for further research on the potential benefits of L-theanine in mammals. Future studies could explore the molecular mechanisms, test L-theanine in mammalian models, and assess the long-term side effects. [ABSTRACT FROM AUTHOR]

Biotechnological pharmaceuticals is a key course offered to third-year undergraduates majoring in biotechnology in our university. However, students often experience difficulties in understanding the principles of related technologies. In this study, we developed and implemented an elective course on preliminary structural biology for biotechnology undergraduates, aiming at reinforcing the principles of these technologies by experimental practice. The course was composed of three phases and lasted for 15 weeks, 18 students were randomly divided into six teams and were encouraged to design, prepare, carry out, and conclude a project on their own. The main contents of their project were cloning, expression, purification, and crystal screening of HpaA, a lipoprotein from the gastric pathogen "Helicobacter pylori". Examination scores of biotechnology pharmaceuticals were used to assess learning outcomes. The results showed that students who participated in this course gained higher scores in the final examination, and they performed better on the questions specifically related to the elective course. These results demonstrated that the course enhanced students' understanding of the technologies involved in this course by practical applications. Thus, this elective course was effective in helping biotechnology undergraduates to learn the theory and application of biological technologies, and the experience gained in this course may be useful for other technology-based courses.

Klebsiella pneumoniae (K. pneumoniae), especially those with hypervirulence, is becoming a global concern and posing great threat to human health. Studies on individual immune cells or cytokines have partially revealed the function of the host immune defense against K. pneumoniae pulmonary infection. However, systematic immune response against K. pneumoniae has not been fully elucidated. Herein, we report a transcriptome analysis of the lungs from a mouse pneumonia model infected with a newly isolated K. pneumoniae clinical strain YBQ. Total RNA was isolated from the lungs of mice 48 hours post infection to assess transcriptional alteration of genes. Transcriptome data were analyzed with KEGG, GO, and ICEPOP. Results indicated that upregulated transcription level of numerous cytokines and chemokines was coordinated with remarkably activated ribosome and several critical immune signaling pathways, including IL-17 and TNF signaling pathways. Notably, transcription of cysteine cathepsin inhibitor (stfa1, stfa2, and stfa3) and potential cysteine-type endopeptidase inhibitor (cstdc4, cstdc5, and cstdc6) were upregulated. Results of ICEPOP showed neutrophils functions as the most essential cell type against K. pneumoniae infection. Critical gene alterations were further validated by rt-PCR. Our findings provided a global transcriptional perspective on the mechanisms of host defense against K. pneumoniae infection and revealed some unique responding genes. [ABSTRACT FROM AUTHOR]