Coronavirus disease 2019 (COVID-19) is newly emerging human infectious diseases, which is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2, also previously known as 2019-nCoV). Within two months of the outbreak, more than 80,000 cases of COVID-19 have been confirmed worldwide. Since the human to human transmission occurred easily and the human infection is rapidly increasing, the sensitive and early diagnosis is essential to prevent the global outbreak. Recently, World Health Organization (WHO) announced various primer and probe sets for SARS-CoV-2 previously developed in China, Germany, Hong Kong, Japan, Thailand, and USA. In this study, we compared the ability to detect SARS-CoV-2 RNA among the seven primer-probe sets for N gene and the three primer-probe sets for Orf1 gene. The result of the comparative analysis represented that the ‘2019-nCoV_N2, N3’ of USA and the ‘ORF1ab’ of China are the most sensitive primer-probe sets for N and Orf1 genes, respectively. Therefore, the appropriate combination from ORF1ab (China), 2019-nCoV_N2, N3 (USA), and NIID_2019-nCOV_N (Japan) sets should be selected for the sensitive and reliable laboratory confirmation of SARS-CoV-2.

Fibrous aggregates of Tau protein are characteristic features of Alzheimer disease. We applied high resolution atomic force and EM microscopy to study fibrils assembled from different human Tau isoforms and domains. All fibrils reveal structural polymorphism; the "thin twisted" and "thin smooth" fibrils resemble flat ribbons (cross-section ϳ10 ؋ 15 nm) with diverse twist periodicities. "Thick fibrils" show periodicities of ϳ65-70 nm and thicknesses of ϳ9 -18 nm such as routinely reported for "paired helical filaments" but structurally resemble heavily twisted ribbons. Therefore, thin and thick fibrils assembled from different human Tau isoforms challenge current structural models of paired helical filaments. Furthermore, all Tau fibrils reveal axial subperiodicities of ϳ17-19 nm and, upon exposure to mechanical stress or hydrophobic surfaces, disassemble into uniform fragments that remain connected by thin thread-like structures (ϳ2 nm). This hydrophobically induced disassembly is inhibited at enhanced electrolyte concentrations, indicating that the fragments resemble structural building blocks and the fibril integrity depends largely on hydrophobic and electrostatic interactions. Because full-length Tau and repeat domain constructs assemble into fibrils of similar thickness, the "fuzzy coat" of Tau protein termini surrounding the fibril axis is nearly invisible for atomic force microscopy and EM, presumably because of its high flexibility.

Single-molecule force measurement methods have attracted increasing interest over recent years for the development of novel approaches for biomolecular screening. However, many of these developments are currently hindered by the available biomolecule surface attachment methods, in that it is still not trivial to create surfaces and devices with highly defined surface functionality and/or uniformity. Here we offer a new approach to address such issues based on the formation of dendron arrays. Through the measurement of forces between dendron surfaces functionalized with complementary DNA oligonucleotides, we observed several unique properties of the surfaces modified via this approach. The capability to record attractive or "jump-in" forces associated with molecular binding events is one of them. Additionally, these events occur in greater than 80% of measurements, and the forces are dependent on the number of complementary DNA bases of the associating strands while being insensitive to the measurement rate. Combined with a narrow distribution of both attractive forces and unbinding forces we suggest such functionalized surfaces offer a significant advance for fast and accurate force-based studies of oligonucleotide hybridization.

A new nanopatterning system based on a soft X-ray induced chemical transformation of a nitro-substituted aromatic imine monolayer has been developed. The molecular layer was exposed to soft X-rays, and the involved chemical transformation on the molecular layer was analyzed by using Fourier transform infrared reflection−absorption spectroscopy. As a result, we could confirm that the nitro group on the imine monolayer was cleaved upon the soft X-ray irradiation, leaving the hydrophobic phenyl unit intact on the monolayer surface, while the imine functionality was transformed into a new nonhydrolyzable one. However, the source of the hydrogen atom for the reduction and the final functionality at the para position of the aromatic group are unknown yet. Whereas, we could restore the hydrophilic amine functionality from the unexposed imine monolayer through hydrolysis. These phenomena were applied to the patterning of self-assembled monolayers featuring alternating height, chemical reactivity, and wettability. Alternating surface wettability is evident when water is sprayed on a macroscopically patterned substrate and the plate is tilted to drip the water. Also, atomic force microscope images revealed patterns as small as ≤100 nm with regular height and phase variations. The patterned monolayer was further modified with a linker and Cy3-tagged oligonucleotide, sequentially. Fluorescence images showed that the above molecules were selectively immobilized onto the amine-terminated region of the patterned surface.

Single nucleotide polymorphism (SNP) is an abundant form of genetic variation within individuals of species. DNA polymorphism can arise throughout the whole genome at different frequencies in different species. SNP may cause phenotypic diversity among individuals, such as individuals with different color of plants or fruits, fruit size, ripening, flowering time adaptation, quality of crops, grain yields, or tolerance to various abiotic and biotic factors. SNP may result in changes in amino acids in the exon of a gene (asynonymous). SNP can also be silent (present in coding region but synonymous). It may simply occur in the noncoding regions without having any effect. SNP may influence the promoter activity for gene expression and finally produce functional protein through transcription. Therefore, the identification of functional SNP in genes and analysis of their effects on phenotype may lead to better understanding of their impact on gene function for varietal improvement. In this mini-review, we focused on evidences revealing the role of functional SNPs in genes and their phenotypic effects for the purpose of crop improvements.

Hydrophobic attractions, such as aromatic p-p stacking, play an essential role in directing nanoscale molecular assembly, protein folding, DNA double-helix formation, host-guest recognition, and others. [1][2][3][4][5] Proteins often activate hydrophobic interactions, to fold into unique structures in order to function properly, since misfolded proteins impair necessary functions, and sometimes cause certain diseases.[6] Thus, understanding hydrophobic folding processes and their related behavior is critical. To better understand folding, reverse processes have been studied using cone-shaped dendrimers to further sharpen the atomic force microscopy (AFM) tip down to the molecular level. From the dendrimer apex, a highly specific single-strand DNA (ss-DNA) extends into solution ready to lock on to its complementary strand. The folded nano-p-stack (NpS) also contains two ss-DNA handles, one matching the dendrimer on the AFM tip and the other matching the dendrimer on the substrate, thus effectively bridging the AFM tip to a substrate; subsequent pulling of the AFM tip yields characteristic ''nanospring''-like behavior at the single-molecule level.AFM has become a powerful tool to study unfolding and refolding phenomena of nanostructured polymers, including synthetic foldamers (foldable polymers) and biological proteins. [7][8][9][10][11] Single-molecule force spectroscopy, enabled by AFM, has offered novel perspectives, revealing structural and mechanical properties of biopolymers. [12][13][14][15][16][17][18][19] Because one AFM tip typically has enough space to host several molecules, using available AFM tips to directly stretch a single molecule remains challenging. Dendron modification, however, sharpens the AFM tip down to the single-molecule level. Previously, self-assembled cone-shaped dendrons effectively spaced the reactive DNA molecules attached to the dendron apexes. This controlled spacing removed lateral steric hindrance, enhanced hybridization efficiency and reproducibility, and greatly simplified the forcedistance curve. [20][21][22][23][24] Obviously, an ss-DNA molecule ideally situated at the dendrimer apex can effectively hybridize to its complementary strand, providing the selectivity and specificity needed to fish out a desired target. Moreover, DNA hybridization offers tunable strength by varying the number of base pairs. Because DNA hybridizes reversibly, overwhelming AFM mechanical forces will not break the stretched macromolecule, but would rather unzip the DNA duplex; this enables repeated pulling of the same macromolecule.As a model of folded domains, foldamers provide deep insight into folding intricacies because of their beautiful simplicity. [25] The foldamer investigated here is a triblock polymer, DNA-NpS-DNA, in which three perylene moieties form a thermophilic NpS, after actuating the flexible ethylene-glycol hinges (Scheme 1). [26][27][28] Because the foldamer specifically hybridizes to the DNA molecules on the dendron-modified substrate and the AFM tip, it effectively bridges the ...

C3HC4-type RING zinc finger proteins are known to be essential in the regulation of plant processes, including responses to abiotic stress. Here, we identify, clone and examine the first C3HC4-type RING zinc finger protein (BrRZFP1) from Brassica rapa under stress conditions. Phylogenetic analysis of BrRZFP1 revealed strong sequence similarity to C3HC4-type zinc finger proteins from Arabidopsis that are induced by abiotic stresses. Diverse environmental stresses, including salt and cold, were found to induce BrRZFP1 transcripts greater than eightfold in B. rapa. Additional strong induction was shown of the stress hormone abscisic acid, together suggesting that BrRZFP1 could play a role as a general stress modulator. Similar profiles of induction for each of these stresses was found in both root and shoot tissues, although at much higher levels in roots. Constitutive expression of BrRZFP1 in Nicotiana tabacum was conducted to further analyse how changes in gene expression levels would affect plant stress responses. BrRZFP1 overexpression conferred increased tolerance to cold, salt and dehydration stresses. This was observed in several assays examining growth status throughout development, including increased germination, fresh weight and length of shoots and roots, as well as enhanced chlorophyll retention. These results suggest that the transcription factor BrRZFP1 is an important determinant of stress response in plants and that changes in its expression level in plants could increase stress tolerance.

Malocclusion is considered as a developmental disorder rather than a disease, and it may be affected by the composition and proportions of masseter muscle fibers. Orthodontics is a specialty of dentistry that deals with diagnosis and care of various irregular bite and/or malocclusion. Recent developments of 3D scanner and 3D printing technology has led to the use of a removable thermoplastic aligner (RTA), which is widely used due to its aesthetic excellence, comfortableness, and time efficiency. However, orthodontics using only an RTA has lower treatment efficacy and accuracy due to the differing movement of teeth from the plan. In order to improve these disadvantages, attachments were used, and biomechanical analyses were performed with and without them. However, there is insufficient research on the movement of teeth and the transfer of load according to the attachment position and shape. Therefore, in our study, we aimed to identify the optimal shape and position of attachments by analyzing various shapes and positions of attachments. Through 3D finite element analysis (FEA), simple tooth shape and mandibular canine shape were extracted in order to construct the orthodontics model which took into account the various shapes and positions of attachments. The optimal shape of a cylinder was derived through the FEA of simple tooth shape and analyzing various positions of attachments on teeth revealed that fixing the attachments at the lingual side of the tooth rather than the buccal side allowed for torque control and an effective movement of the teeth. Therefore, we suggest fixing the attachments at the lingual side rather than the buccal side of the tooth to induce effective movement of teeth in orthodontic treatment with the RTA in case of canine teeth.