Research advances in detection of food adulteration and application of MALDI-TOF MS: A review.

Food adulteration and illegal supplementations have always been one of the major problems in the world. The threat of food adulteration to the health of consumers cannot be ignored. Food of questionable origin causes economic losses to consumers, but the potential health risks cannot be ignored. However, the traditional detection methods are time-consuming and complex. This review mainly discusses the types of adulteration and technologies used to detect adulteration. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) is also emphasized in the detection of adulteration and authenticity of origin analysis of various types of food (milk, meat, edible oil, etc.), and the future application direction and feasibility of this technology are analyzed. On this basis, MALDI-TOF MS was compared with other detection methods, highlighting the advantages of this technology in the detection of food adulteration. The future development prospect and direction of this technology are also emphasized.

Prenatal Genetic Diagnosis and Origin Analysis of Rare Complete Translocation Trisomy 18 / 中山大学学报(医学科学版)

ObjectiveTo discuss the origin of rare abnormal karyotypes of fetuses with high risk of trisomy 18 revealed by non-invasive prenatal testing （NIPT） and its impact on fertility. MethodsThe cytogenetic and molecular genetic analyses were performed on the abnormal chromosomes of a prenatally diagnosed fetus with rare complete translocation trisomy 18. Using the keywords “translocation trisomy 18” or “trisomy 18 translocation” in both Chinese and English， we searched PubMed， CNKI， SinoMed， WanFang Data， CQ VIP and the Chinese Medicine database. The relevant case series were retrieved and critically appraised. ResultsG-banded karyotype analysis showed that the maternal karyotype was 46，XX，t（9；18）（q31.2；q23） and the fetal karyotype was 47， XN， t （9； 18） （q31.2；q23）mat， +18， which was a rare complete translocation type of trisomy 18. The SNP array revealed the fetus had increased copy number of chromosome 18 and two complete chromosome 18 inherited from the mother with balanced chromosomal translocation. Literature search found two children with complete translocation trisomy 18 reported abroad. Both of them had trisomy 18 phenotype and originated from the balanced translocation between parental chromosome 18 and other chromosomes. ConclusionNIPT gives an effective advance warning of trisomy 18. SNP array not only improves the detection rate of chromosomal abnormalities， but also helps identify the origin. The karyotype is still the gold standard for prenatal diagnosis.

Spatial origin analysis on atmospheric bulk deposition of polycyclic aromatic hydrocarbons in Shanghai.

Atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) onto soil threatens terrestrial ecosystem. To locate potential source areas geographically, a total of 139 atmospheric bulk deposition samples were collected during 2012-2019 at eight sites in Shanghai and its surrounding areas. A multisite joint location method was developed for the first time to locate potential source areas of atmospheric PAHs based on an enhanced three dimensional concentration weighted trajectory model. The method considered spatial and temporal variations of atmospheric boundary layer height and homogenized all results over the eight sites via geometric mean. Regional transport was an important contributor of PAH atmospheric deposition while massive local emissions may disturb the identification of potential source areas. Northwesterly winds were associated with elevated deposition fluxes. Potential source areas were identified by the multisite joint location method and included Hebei, Tianjin, Shandong and Jiangsu to the north, and Anhui to the west of Shanghai. PM and SO2 data from the national ground monitoring stations confirmed the identified source areas of deposited PAHs in Shanghai.

Constraining parameter uncertainty for predicting oxygen and hydrogen isotope values in fruit.

Understanding δ18O and δ2H values of agricultural products like fruit is of particular scientific interest in plant physiology, ecology, and forensic studies. Applications of mechanistic stable isotope models to predict δ18O and δ2H values of water and organic compounds in fruit, however, are hindered by a lack of empirical parameterizations and validations. We addressed this lack of data by experimentally evaluating model parameter values required to model δ18O and δ2H values of water and organic compounds in berries and leaves from strawberry and raspberry plants grown at different relative humidities. Our study revealed substantial differences between leaf and berry isotope values, consistent across the different relative humidity treatments. We demonstrated that existing isotope models can reproduce water and organic δ18O and δ2H values for leaves and berries. Yet, these simulations require organ-specific model parameterization to accurately predict δ18O and δ2H values of leaf and berry tissue and water pools. We quantified these organ-specific model parameters for both species and relative humidity conditions. Depending on the required model accuracy, species- and environment-specific model parameters may be justified. The parameter values determined in this study thus facilitate applications of stable isotope models where understanding δ18O and δ2H values of fruit is of scientific interest.

Epigenetic Biomarkers in Cell-Free DNA and Applications in Liquid Biopsy.

Cell-free circulating DNA (cfDNA) in plasma has gained global interest as a diagnostic material for noninvasive prenatal testing and cancer diagnosis, or the so-called "liquid biopsy". Recent studies have discovered a great number of valuable genetic and epigenetic biomarkers for cfDNA-based liquid biopsy. Considering that the genetic biomarkers, e.g., somatic mutations, usually vary from case to case in most cancer patients, epigenetic biomarkers that are generalizable across various samples thus possess certain advantages. In this study, we reviewed the most recent studies and advances on utilizing epigenetic biomarkers for liquid biopsies. We first reviewed more traditional methods of using tissue/cancer-specific DNA methylation biomarkers and digital PCR or sequencing technologies for cancer diagnosis, as well as tumor origin determination. In the second part, we discussed the emerging novel approaches for exploring the biological basis and clinical applications of cfDNA fragmentation patterns. We further provided our comments and points of view on the future directions on epigenetic biomarker development for cfDNA-based liquid biopsies.

[Hydrochemical Characteristics of Groundwater and the Origin in Alluvial-proluvial Fan of Qinhe River].

To study the hydrochemical characteristics of groundwater and the factors controlling the alluvial-proluvial fan of the Qinhe River, 60 samples were collected including 9 surface water samples and 51 groundwater samples. The distribution characteristics of the hydrochemistry and major controlling factors of hydrochemical evolution processes of surface water and groundwater in the study area were analyzed by using mathematical statistics, the Schakerev classification, Piper diagrams, Schoeller diagrams, Gibbs plots, and ion ratios. The results show that:① the major anions and cations of surface water and groundwater in the study area are Ca2+, Mg2+, SO42-, and HCO3-. The recharge sources of surface water and groundwater are closely related; ② the major hydrochemical types of the groundwater are HCO3-Ca, HCO3-Ca·Mg, and HCO3·SO4-Ca·Mg, while the major hydrochemical type of surface water is HCO3·SO4-Ca·Mg; and ③ the major ions of surface water and groundwater are affected by carbonate mineral weathering and dissolution, ion exchange, and evaporation. Sulfuric acid and carbonic acid were involved in carbonate mineral weathering and dissolution.

Alterações pós-colheita em raízes de mandioquinha-salsa (Arracacia xanthorrhiza Bancroft): atividade enzimática, identificação de contaminante e caracterização parcial do amido / Alterations after harvest in peruvian carotovora (arracacia santhorrhiza bancroft) roots: enzymatic activity, pollutant identification and partial characterization of the starch

Este trabalho teve como principais objetivos verificar as alterções na atividade de enzimas amilolíticas, pectinolíticas e celulásicas em raízes de mandioquinha-salsa durante o período pós-colheita, sob diferentes condições de armazenamento, visando avaliar os mecanismos de deterioração das raízes, bem como identificar o microrganismo possivelmente responsável pela alta perecibilidade das raízes. Além disso, foram estudadas características físico-químicas e reológicas do amido de mandioquinha extraído em laboratório. Para a detecção de atividade pectinesterásica (PE) e poligalacturonásica (PG) nas raízes, os parâmetros de extração destas enzimas foram otimizados através de metodologia de superfície de resposta (MSR)...

The aim of this work was to verify the changes in amylolytic, pectinolytic and cellulasic activity in Peruvian carrot roots after harvest, under different storage conditions, in order to evaluate the deteriorative mechanisms of the roots, as well as to identify the microorganism possible responsible to its low conservation time. In addition, physico-chemical and rheological characteristics of Peruvian carrot starch were studied. For pectinesterase (PE) and poligalacturonase (PG) detection on the roots, the extraction parameters of both enzymes were optimized by response surface methodology. The enzymes presented the optimum pH values at 7.5 and 4.0 for PE and PG, respectively. Extraction time and NaCI concentration were considered non-significant by the model. Pectic enzymes seams to be related to the deterioration process of Peruvian carrot, that is associated to the root softening. Considering the high volume of gas under specific packing and temperature, the presence of microorganisms soft rot promoters could be the main cause of the high perecibility of the roots. The amylolytic enzymes present an important role on Peruvian carrot deterioration related to the starch hydrolysis and the releasing of reducing sugars, substrate for opportunistic microorganisms. The cellulasic activity was not significant during storage time. Best conditions for roots conservation occurred at 4°C and under vacuum package. The bacteria isolated from the roots were identified by biochemical reactions as Erwinia carotovora subsp. odorifera. Peruvian carrot...