DNA-based geographic typing of the gourmet mushroom <Emphasis Type="Italic">Tricholoma matsutake</Emphasis> traded in China

Tricholoma matsutake is among the most valuable mushrooms in the world, and natural populations of this species from different geographic regions are priced very differently. To examine the geographic origins of ‘matsutake’ mushrooms traded in China, we analyzed the mushrooms from two major production and trading regions in China, the Southwest and the Northeast, using a recently published retroelement-based DNA marker. Our analyses showed that 67% of commercial matsutake claimed to be from the northeast were in fact genetically identical to those from the southwest but were different from authentic northeast samples. The finding suggests that caution should be applied to the authentication of commercial matsutake from northeast China.     

Intercomparison of 99mTc, 18F and 111In activity measurements with radionuclide calibrators in Belgian hospitals

This study presents current status of performance of radiopharmaceutical activity measurements using radionuclide calibrators in Belgium. An intercomparison exercise was performed among 15 hospitals to test the accuracy of ^99mTc, ¹⁸F and ¹¹¹In activity measurements by means of radionuclide calibrators. Four sessions were held in different geographical regions between December 2013 and February 2015. The data set includes measurements from 38 calibrators, yielding 36 calibrations for ^99mTc and ¹¹¹In, and 21 calibrations for ¹⁸F. For each radionuclide, 3 ml of stock solution was measured in two clinical geometries: a 10 ml glass vial and a 10 ml syringe. The initial activity was typically 100 MBq for ^99mTc, 15 MBq for ¹¹¹In and 115 MBq for ¹⁸F. The reference value for the massic activity of the radioactive solutions was determined by means of primary and secondary standardisation techniques at the radionuclide metrology laboratory of the JRC.The overall results of the intercomparison were satisfactory for ^99mTc and ¹⁸F, since most radionuclide calibrators (>70%) were accurate within ±5% of the reference value. Nevertheless, some devices underestimated the activity by 10–20%. Conversely, ¹¹¹In measurements were strongly affected by source geometry effects and this had a negative impact on the accuracy of the measurements, in particular for the syringe sample. Large overestimations (up to 72%) were observed, even when taking into account the corrections and uncertainties supplied by the manufacturers for container effects. The results of this exercise encourage the hospitals to perform corrective actions to improve the calibration of their devices where needed.     

副溶血性弧菌Vibrio parahaemolyticus O3:K6大流行克隆的溯源

副溶血性弧菌(Vibrio Parahaemolyticus)是一种革兰氏阴性嗜盐性海洋细菌。1950年从日本一次暴发性食物中毒中首次分离发现。作为一种食源性人鱼共患致病菌,副溶血性弧菌在全球的河口、海洋和沿海广泛传播,由其引起的食物中毒已跃居其它病原菌之首。副溶血性弧菌在进化过程中通过基因重组和基因水平转移逐渐改善其对环境的适应性,因而与其它所有致病微生物相比,副溶血性弧菌的基因型和血清型都具有高度的多样性。本文就副溶血性弧菌,特别是1996年后在世界范围内出现的O3:K6新血清型流行株(形成所谓的O3:K6大流行克隆Pandemic clone)的发现及流行特征、变异分子流行病学特征、在我国的分布及研究进展进行综述,以期为O3:K6大流行克隆的溯源提供更多依据。     

Tracing the origins of stocks of the endangered species <Emphasis Type="Italic">Primula sieboldii</Emphasis> using nuclear microsatellites and chloroplast DNA

We examined the origins of cultivated stocks of the endangered species Primula sieboldii at the individual plant level by using an assignment test based on eight microsatellite loci and regional features of chloroplast DNA (cpDNA) variation of wild populations. To confirm that we had sufficient information for estimating the origins of the stocks, we performed an assignment test with 920 genets that we collected from 32 wild populations with known origins. The test assigned 99.6% of the genets to the population from which they had been sampled, confirming the suitability of the method. We then performed the assignment test with 29 cultivated stocks. The alleged origins of 19 were confirmed by microsatellite and cpDNA variations. In contrast, the alleged origins of five were rejected by both markers. Five stocks, which do not have a reference population located within 30 km of their reputed origin, were not assigned to any population. Stocks whose alleged origins were rejected are inappropriate as restoration materials, because their introduction might disturb local gene pools. Six stock haplotypes could not be detected in wild populations. This may suggest the loss of genetic diversity in the wild and the value of stocks as a gene bank. The genetic method used in this study will also be helpful to detect cryptic invasion by nonendemic genotypes or to trace the origins of plants collected for commercial purposes, a threat to many endangered species.     

A review of the calibration methods for measuring the carbon and oxygen isotopes in CO2 based on isotope ratio infrared spectroscopy北大核心CSCD

With the development of isotope ratio infrared spectroscopy (IRIS) technology, it is now possible for the in situ high temporal resolution and high precision measurement of carbon isotopic composition (d13C) and oxygen isotopic composition (d18O) of atmospheric CO2, which overcomes the low temporal resolution and labor intensive shortcoming of traditional isotope ratio mass spectrometry (IRMS). The dependence of d13C and d18O on CO2 concentration (termed as concentration dependence) and the drift due to sensitivity to changing environmental conditions (termed as instrumental drift) are the two main sources of error affecting the IRIS measurements. Therefore, it is important to obtain precise measurements by constructing a proper calibration strategy to solve the concentration dependence and instrumental drift. In this study, we briefly discussed the definition and related theoretical principle of concentration dependence, and elaborated the theoretical and empirical calibration methods of concentration dependence. Moreover, we introduced the calibration methods of instrumental drift, and reviewed the state of the art of calibration methods and its application of IRIS technology. Additionally, we briefly discussed the definition and method of data traceability to the international standard, and reviewed its application of IRIS technology. Finally, we recommend that concentration dependence is corrected by using three standards or above with known CO2 concentration and its d13C and d18O, bracketing the CO2 concentration of samples. The instrumental drift is corrected by setting appropriate calibration frequency and all dataset are traceable to the international standard. In the future, the comparative study of different IRIS instruments and calibration methods should be enhanced, and the similar methods should be used for measuring CH4, N2O and H2O isotopes by IRIS technique. The IRIS technology combined with other technology will provide a new opportunity for ecological research. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All rights reserved.     

新疆和田、哈密和阿勒泰市居民指甲中氢、氧稳定同位素的比较

在法庭科学研究领域,指甲作为一种新型生物信息载体,在物证信息挖掘方面具有重要的价值。人生命活动中摄入的氢、氧主要来源于饮用水、摄入的食物和空气等,其中的氢、氧稳定同位素比值信息会被指甲角蛋白记录并保存下来,这些信息可以用于推断人的生活地域变化情况,在个体身份的排查工作中具有重要的作用。本文借助元素分析-稳定同位素比质谱技术（EA-IRMS）对新疆和田、哈密和阿勒泰3个城市常住居民指甲中氢、氧稳定同位素比值进行了分析,并借助判别分析模型对指甲样本的氢、氧稳定同位素比值进行了模式识别。结果表明,3个不同城市常住居民指甲氢、氧稳定同位素比值存在一定的差异;和田指甲样本δ²H值与哈密、阿勒泰有明显差异;哈密指甲样本δ²H值与阿勒泰重叠范围宽,差异较小;3个城市δ¹⁸O值分布均有重叠,无明显的差异。在判别模型中,通过判别函数f(x,y)=0.992x+0.046y和判别函数f(x,y)=-0.198x+1.009y对3个市共计85份样本进行判别分析,总体分类准确率为95.29 %,9个验证样本均实现了准确的归类和判定。本文研究表明,不同城市居民指甲中的氢、氧稳定同位素比值是存在一定差异的,采用EA-IRMS结合判别分析能初步实现不同城市居民的区分。     

The European Joint Research Project UHDpulse – Metrology for advanced radiotherapy using particle beams with ultra-high pulse dose rates

UHDpulse – Metrology for advanced radiotherapy using particle beams with ultra-high pulse dose rates is a recently started European Joint Research Project with the aim to develop and improve dosimetry standards for FLASH radiotherapy, very high energy electron (VHEE) radiotherapy and laser-driven medical accelerators. This paper gives a short overview about the current state of developments of radiotherapy with FLASH electrons and protons, very high energy electrons as well as laser-driven particles and the related challenges in dosimetry due to the ultra-high dose rate during the short radiation pulses. We summarize the objectives and plans of the UHDpulse project and present the 16 participating partners.     

Quantification of protein calibrants by amino acid analysis using isotope dilution mass spectrometry

This work demonstrates that amino acid analysis based on isotope dilution mass spectrometry (IDMS) can be applied to quantify proteins having different complexities and natures. Five proteins and one decapeptide were selected for the study: C-reactive protein (CRP), beta-2-microglobulin (B2 M), cystatine C (CysC), human serum albumin (HSA), Ara h1, and angiotensin I. The quantification was based on the determination of four amino acids, proline (Pro), isoleucine (Ile), valine (Val), and phenylalanine (Phe) within a working range between 5 and 100 pmol/injection of each amino acid, after 60 min digestion with HCl at 150 °C. The amino acids were selected taking into account their abundance in the protein sequence and to include the more difficult to break peptide bonds. Quantification of the protein amounts calculated from each amino acid is consistent, indicating that the method is working reliably. This consistency points to a complete hydrolysis of the proteins. The trueness of the method was proven when dry mass determination after dialysis was applied to HSA and CRP and the results were compared to those from amino acid analysis. Traceability to SI was assured by extensive characterisation of the amino acid calibrants by nuclear magnetic resonance, neutron activation analysis, and Karl Fischer titration.