Distinguishing features of Prunus humilis, P. japonica, P. pedunculata seeds and their adulterant based on DNA barcoding, morphological characterization, and chemical profiles

Pruni Semen, the dried ripe seed of Prunus humilis, P. japonica, or P. pedunculata as recorded in the Chinese Pharmacopoeia, has been widely used in pharmaceutical and food industries. The adulteration of the marketed product with morphologically similar plants of the same genus has led to variable product quality and clinical effectiveness. This study systematically investigated the phylogenetic relationships, morphological traits, and chemical profiles of 37 Pruni Semen samples from planting bases, markets, and fields. DNA barcoding could successfully distinguish the genuine and counterfeit Pruni Semen, and the results indicated that there was almost no authentic Pruni Semen available in the market. The samples were divided into "big seed" (P. pedunculata and P. salicina seeds) and "small seed" (P. humilis, P. japonica, P. tomentosa, and P. avium seeds) categories based on morphology results. The notable discrepancy in the chemical characteristics of "big seed" and "small seed" was that "small seeds" were rich in flavonoids and low in amygdalin, whereas "big seeds" were the opposite. Furthermore, principal component analysis and clustered heatmap analysis verified the distinguishing features of "big seed" and "small seed" based on morphological and chemical characteristics. This study suggested that a combination of DNA barcoding and morphological and chemical characteristics can aid in the identification and quality evaluation of authentic and adulterated Pruni Semen. These findings may help standardize Pruni Semen available in the market and protect the rights and interests of customers.

A case study on DNA barcoding for pet food mislabeling in South Korea

Due to the close relationship between pets and humans, pet owners are highly invested in proper diets for their pets. Even though pet food mislabeling is concerning, there are few studies on this topic. This study investigated pet food mislabeling in South Korea’s market based on DNA barcoding. In total, 10 pet food products were purchased, and 200 sequences of the partial Cytochrome c oxidase subunit 1 (COI) gene were generated from clones of the samples. The obtained sequences were compared to available public databases to identify species present in the ingredients. The data analyses showed that the labeled species were consistent with species detected by COI sequences in 6 of the products. However, the expected species were not detected in 4 products, revealing possible mislabeling in these samples. Our findings indicated that DNA barcoding might represent a promising tool to detect pet food mislabeling.

Authentication, chemical profiles analysis, and quality evaluation of corn silk via DNA barcoding and UPLC-LTQ/Orbitrap MS chemical profiling

Corn silk is commonly consumed in teas, food ingredients, and herbal medicines. Several varieties of corn silk are grown in different habitats in China. However, as information regarding their phytochemistry and genetic diversity is limited, their medicinal potential has not been utilized thoroughly. Thus, we aimed to use a combination of DNA barcoding based on specific primer ITSC sequences and ultra-performance liquid chromatography coupled with linear trap quadrupole-Orbitrap mass spectrometry (UPLC-LTQ/Orbitrap MS) approach for identifying and evaluating corn silk. ITSC barcoding helped us to identify that 52 samples could be classified into 7 groups of corn silk varieties, but the widely used nrITS and psbA-trnH barcodes failed to identify these varieties. UPLC-LTQ/Orbitrap MS was used to study the components in alcohol extracts derived from different corn silk varieties, and the detected chemical components were analyzed via bioinformatics techniques. We proposed 199 components using untargeted UPLC-LTQ/Orbitrap MS-based metabolomics analysis and identified 67 components. PCA and OPLS-DA analysis revealed two distinct chemotypes by selecting 27 components that could act as difference indicators. KEGG analysis showed that the 199 components were enriched in 12 metabolic pathways. The results showed that corn silk is rich in many types of chemicals and DNA barcoding is better than UPLC-LTQ/Orbitrap MS in distinguishing the differences between different varieties of corn silk. Our findings provide new insights into the chemical and molecular characteristics of different varieties of corn silk, which play a crucial role in the utilization of corn silk resources.

Pragmatic applications of DNA barcoding markers in identification of fish species – a review

DNA barcoding and mini barcoding involve Cytochrome Oxidase Subunit I (COI) gene in mitochondrial genome and is used for accurate identification of species and biodiversity. The basic goal of the current study is to develop a complete reference database of fishes. It also evaluates the applicability of COI gene to identify fish at the species level with other aspects i.e., as Kimura 2 parameter (K2P) distance. The mean observed length of the sequence was ranging between 500 to 700 base pairs for fish species in DNA barcoding and 80 to 650 base pairs for DNA mini barcoding. This method describes the status of known to unknown samples but it also facilitates the detection of previously un-sampled species at distinct level. So, mini-barcoding is a method focuses on the analysis of short-length DNA markers has been demonstrated to be effective for species identification of processed food containing degraded DNA. While DNA meta-barcoding refers to the automated identification of multiple species from a single bulk sample. The may contain entire organisms or a single environmental sample containing degraded DNA. Despite DNA barcoding, mini barcoding and meta-barcoding are efficient methods for species identification which are helpful in conservation and proper management of biodiversity. It aids researchers to take an account of genetic as well as evolutionary relationships by collecting their morphological, distributional and molecular data. Overall, this paper discusses DNA barcoding technology and how it has been used to various fish species, as well as its universality, adaptability, and novel approach to DNA-based species identification.

Combining DNA Mini-Barcoding and Species-Specific Primers PCR Technology for Identification of Heosemys grandis

Heosemys grandis, a species of Asian water turtle, that has a wide range of applications in the food and pharmaceutical industries. Since some processed products cannot be identified exclusively by morphological and microscopic identification, a reliable and quick approach to guarantee authenticity is critical. Thus, we fostered an effective and stable molecular identification system to identify Heosemys grandis based on DNA mini-barcoding and species-specific primers PCR technology. A total of 48 turtle samples from 16 different species were collected. To distinguish Heosemys grandis from its counterfeits, DNA mini-barcoding and a pair of species-specific primers were designed and verified by PCR after analyzing the COI sequences of samples. The results showed that only Heosemys grandis samples could generate a single clear band following amplification using species-specific primers. Employing DNA mini-barcoding to amplify samples can verify authenticity by sequence alignment. These findings indicated that species-specific primers PCR technology combined with DNA mini-barcoding could accurately detect the authenticity of Heosemys grandis. This technology broadens the application of molecular biology techniques in the food and pharmaceutical industries. It provides a reliable and convenient method for identifying raw materials to standardize the market and protect customers’ rights and interests.

Biodiversity of South Indian tea clones with detection of plant-based adulterants in tea dust using DNA barcoding

Tea is by and large a highly penetrated product in south India. Hence the adulteration risk in tea dust gets hiked in the markets. We constructed a standard database using plant plastid markers (rbcL, matK, trnH-psbA, rpoC, rpoB, ycf 1) and nuclear (ITS2) locus from prominent south Indian tea clones representing Assam, China, and Cambod varieties. These barcodes were used as reference algorithm to investigate the authenticity of 10 sampled commercial tea dust by recovering its DNA barcodes using rbcL, matK, and ITS2 loci. PCR amplification success, sequencing efficiency, genetic polymorphisms, BLAST search, and phylogenetic analysis were performed to enhance genotypic information on south tea cultivars and in authenticating the commercial samples of Camellia sinensis. Findings suggest that the chloroplast and nuclear loci can identify tea plant at the genus and varietal level respectively and rbcL as the potential marker for detecting plant-based admixtures coupled with TA cloning after DNA barcoding.

DNA-based techniques for seafood species authentication

Global trade of seafood has increased in the last decade, leading to significant concerns associated with seafood fraud. Seafood fraud involves the intentional misrepresentation of fish or shellfish for the purpose of economic gain and includes acts such as species substitution, illegal transshipment, overtreatment/short weighting, and mislabeling country of origin or production method. These fraudulent acts have had economic, environmental, and public health consequences on a global level. DNA-based techniques for seafood authentication are utilized by regulatory agencies and can be employed as part of a food fraud risk mitigation plan. This chapter will focus specifically on the use of DNA-based methods for the detection of seafood species substitution. Various methods have been developed for DNA-based species identification of seafood, including polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), species-specific PCR, real-time PCR, Sanger sequencing, microarrays, and high-resolution melting (HRM). Emerging techniques for seafood authentication include droplet digital PCR, isothermal amplification, PCR-enzyme-linked immunosorbent assay (ELISA), and high-throughput or next-generation sequencing. Some of these DNA-based methods target specific species, such as real-time PCR and droplet digital PCR, while other methods allow for simultaneous differentiation of a wide range of fish species, including Sanger sequencing and high-throughput sequencing. This chapter will begin with an introduction on seafood fraud and species substitution, followed by an analysis of the main DNA-based authentication methods and emerging techniques for species identification.