Since the outbreak of coronavirus disease 2019 (COVID-2019), the infection has spread worldwide due to the highly contagious nature of severe acute syndrome coronavirus (SARS-CoV-2). To manage SARS-CoV-2, the development of diagnostic assays that can quickly and accurately identify the disease in patients is necessary. Currently, nucleic acid-based testing and serology-based testing are two widely used approaches. Of these, nucleic acid-based testing with quantitative reverse transcription-PCR (RT-qPCR) using nasopharyngeal (NP) and/or oropharyngeal (OP) swabs is considered to be the gold standard. Recently, the use of saliva samples has been considered as an alternative method of sample collection. Compared to the NP and OP swab methods, saliva specimens have several advantages. Saliva specimens are easier to collect. Self-collection of saliva specimens can reduce the risk of infection to healthcare providers and reduce sample collection time and cost. Until recently, the sensitivity and accuracy of the data obtained using saliva specimens for SARS-CoV-2 detection was controversial. However, recent clinical research has found that sensitive and reliable data can be obtained from saliva specimens using RT-qPCR, with approximately 81% to 95% correspondence with the data obtained from NP and OP swabs. These data suggest that self-collected saliva is an alternative option for the diagnosis of COVID-19.

Recently, the importance of on-site detection of pathogens has drawn attention in the field of molecular diagnostics. Unlike in a laboratory environment, on-site detection of pathogens is performed under limited resources. In this study, we tried to optimize the experimental conditions for on-site detection of pathogens using a combination of ultra-fast convection polymerase chain reaction (cPCR), which does not require regular electricity, and nucleic acid lateral flow (NALF) immunoassay. Salmonella species was used as the model pathogen. DNA was amplified within 21 minutes (equivalent to 30 cycles of polymerase chain reaction) using ultra-fast cPCR, and the amplified DNA was detected within approximately 5 minutes using NALF immunoassay with nucleic acid detection (NAD) cassettes. In order to avoid false-positive results with NAD cassettes, we reduced the primer concentration or ultra-fast cPCR run time. For singleplex ultra-fast cPCR, the primer concentration needed to be lowered to 3 μM or the run time needed to be reduced to 14 minutes. For duplex ultra-fast cPCR, 2 μM of each primer set needed to be used or the run time needed to be reduced to 14 minutes. Under the conditions optimized in this study, the combination of ultra-fast cPCR and NALF immunoassay can be applied to on-site detection of pathogens. The combination can be easily applied to the detection of oral pathogens.

There have been great efforts to develop a rapid and sensitive detection method to monitor the presence of pathogenic bacteria in food. While a number of methods have been reported for bacterial detection with a detection limit to a single digit, most of them are suitable only for the bacteria in pure culture or buffered solution. On the other hand, foods are composed of highly complicated matrices containing carbohydrate, fat, protein, fibers, and many other components whose composition varies from one food to the other. Furthermore, many components in food interfere with the downstream detection process, which significantly affect the sensitivity and selectivity of the detection. Therefore, isolating and concentrating the target pathogenic bacteria from food matrices are of importance to enhance the detection power of the system. The present review provides an introduction to the representative sample preparation strategies to isolate target pathogenic bacteria from food sample. We further describe the nucleic acidbased detection methods, such as PCR, real-time PCR, NASBA, RCA, LCR, and LAMP. Nucleic acid-based methods are by far the most sensitive and effective for the detection of a low number of target pathogens whose performance is greatly improved by combining with the sample preparation methods.

구기자응애 (Eriophyes kuko Kishida)의 침입 기생에 의하여 구기자나무(Lycium chinense Mill)의 잎에 형성되는 혹(Mite gall)의 성장에 따르는 표피세포와 핵의 크기를 측정하는 동시에 핵산(DNA, RNA)의 함량(함량으로 표시되느 농도분포)을 현미분광측정기(Microspectrophotometer)로 측정한 그 결과를 요약하면 다음과 같다. 1. 혹이 성장함에 따라 표피세포와 핵이 커지며 건전한 것보다 크게 된다. 2. DNA의 함량(함량으로 표시되는 농도분포)은 혹이 형성되는 초기에는 별로 변동이 없는 것 같으나 성장한 혹에 있어서는 건전한 것보다 오히려 증가하는 경향이 보였다. 3. RNA의 함량(함량으로 표시되는 농도분포)은 혹이 형성되는 초기부터 중기까지는 일시 적으로 증가하는 것 같으나 혹이 성장하게되면 건전한 것보다 오히려 감소되는 경향이 보였다. I

GnRH (gonadotropin-releasing hormone) is a supreme hormone regulating reproductive activity in most animals. The sequences of amino acid and nucleic acid of GnRH reported up to now are examined from the evolutionary framework of Chordata. All identified GnRH are classified into GnRH1, GnRH2, or GnRH3. In all three forms of GnRH both N-terminal and C-terminal are conserved, which allows for effective binding to their receptors. The three amino acids in the middle of GnRH1 sequence have altered diversely from the primitive Chordata, which is indicative of the adaptation process to the ambient environment. GnRH2 and GnRH3 sequences are well conserved. There are more diverse modifications in the nucleic acids than in amino acid sequence of GnRH1. These variations can result from meiosis, mutation, or epigenetics and indicate that GnRH is the product of natural selection.

This study was carried out to identify Korean ginseng cultivars using peptide nucleic acid (PNA) microarray. Sixty-seven probes were designed based on nucleotide variation to distinguish Korean ginseng cultivars of Panax ginseng. Among those PNA probes, three (PGB74, PGB110 and PGB130) have been developed to distinguish five Korean ginseng cultivars. Five Korean ginseng cultivars were denoted as barcode numbers depending on their fluorescent signal patterns of each cultivar using three probe sets in the PNA microarray. Five Korean ginseng cultivars, Chunpoong, Yunpoong, Gopoong, Gumpoong and Sunpoong, were simply denoted as '111', '222', '211', '221' and '122', respectively. This is the first report of PNA microarray which provided an objective and reliable method for the authentication of Korean ginseng cultivars. Also, the PNA microarray will be useful for management system and pure guarantee in ginseng seed.