Metastable hexagonal close-packed palladium hydride in liquid cell TEM.

Metastable phases-kinetically favoured structures-are ubiquitous in nature1,2. Rather than forming thermodynamically stable ground-state structures, crystals grown from high-energy precursors often initially adopt metastable structures depending on the initial conditions, such as temperature, pressure or crystal size1,3,4. As the crystals grow further, they typically undergo a series of transformations from metastable phases to lower-energy and ultimately energetically stable phases1,3,4. Metastable phases sometimes exhibit superior physicochemical properties and, hence, the discovery and synthesis of new metastable phases are promising avenues for innovations in materials science1,5. However, the search for metastable materials has mainly been heuristic, performed on the basis of experiences, intuition or even speculative predictions, namely 'rules of thumb'. This limitation necessitates the advent of a new paradigm to discover new metastable phases based on rational design. Such a design rule is embodied in the discovery of a metastable hexagonal close-packed (hcp) palladium hydride (PdHx) synthesized in a liquid cell transmission electron microscope. The metastable hcp structure is stabilized through a unique interplay between the precursor concentrations in the solution: a sufficient supply of hydrogen (H) favours the hcp structure on the subnanometre scale, and an insufficient supply of Pd inhibits further growth and subsequent transition towards the thermodynamically stable face-centred cubic structure. These findings provide thermodynamic insights into metastability engineering strategies that can be deployed to discover new metastable phases.

Selective loading and processing of prespacers for precise CRISPR adaptation.

CRISPR-Cas immunity protects prokaryotes against invading genetic elements1. It uses the highly conserved Cas1-Cas2 complex to establish inheritable memory (spacers)2-5. How Cas1-Cas2 acquires spacers from foreign DNA fragments (prespacers) and integrates them into the CRISPR locus in the correct orientation is unclear6,7. Here, using the high spatiotemporal resolution of single-molecule fluorescence, we show that Cas1-Cas2 selects precursors of prespacers from DNA in various forms-including single-stranded DNA and partial duplexes-in a manner that depends on both the length of the DNA strand and the presence of a protospacer adjacent motif (PAM) sequence. We also identify DnaQ exonucleases as enzymes that process the Cas1-Cas2-loaded prespacer precursors into mature prespacers of a suitable size for integration. Cas1-Cas2 protects the PAM sequence from maturation, which results in the production of asymmetrically trimmed prespacers and the subsequent integration of spacers in the correct orientation. Our results demonstrate the kinetic coordination of prespacer precursor selection and PAM trimming, providing insight into the mechanisms that underlie the integration of functional spacers in the CRISPR loci.

Human cytomegalovirus microRNA miR-US4-1 inhibits CD8(+) T cell responses by targeting the aminopeptidase ERAP1.

Major histocompatibility complex (MHC) class I molecules present peptides on the cell surface to CD8(+) T cells, which is critical for the killing of virus-infected or transformed cells. Precursors of MHC class I-presented peptides are trimmed to mature epitopes by the aminopeptidase ERAP1. The US2-US11 genomic region of human cytomegalovirus (HCMV) is dispensable for viral replication and encodes three microRNAs (miRNAs). We show here that HCMV miR-US4-1 specifically downregulated ERAP1 expression during viral infection. Accordingly, the trimming of HCMV-derived peptides was inhibited, which led to less susceptibility of infected cells to HCMV-specific cytotoxic T lymphocytes (CTLs). Our findings identify a previously unknown viral miRNA-based CTL-evasion mechanism that targets a key step in the MHC class I antigen-processing pathway.

Primo Vessels Inside Lymphatic Vessels Are Absent in an ALS Mouse Model.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the selective death of motor neurons in the central nervous system. It is also a representative rare disease among degenerative diseases of the nervous system. Although many drugs for the treatment of degenerative brain diseases are being developed, they are not delivered correctly to the target due to the blood-brain barrier. The present study aimed to analyze changes in the primo vascular system (PVS) in ALS mice with symptoms and the partial oxygen pressure (pO2) in normal mice. In normal mice, we consistently observed primo vessels in lymphatic vessels (L-PVS). However, in ALS mice with symptoms, L-PVS were mostly lost, rendering them difficult to observe. The pO2 of the L-PVS in normal mice was significantly higher than that of normal dermis and lymph nodes.In conclusion, the relatively higher oxygen levels measured in the L-PVS than in normal dermis and lymph nodes suggest a role for the PVS in oxygen transport and enable a hypothesis that the L-PVS can function as a drug delivery pathway.

Tissue Concentration Analysis of Sulfur, Calcium and Oxygen in Novel Skin Primo Nodes After Acupuncture.

Over the past 5000 years, acupuncture has been practiced in Korea, China, and Japan to relieve various diseases, and it is now widely used and accepted worldwide. Although the anatomical substance and function of meridians has been actively studied, it is still not clearly defined. One of the keys to acupuncture is determining the specific anatomical location exactly on or under the skin. We discovered that the skin primo node is a new anatomical structure in the skin of rats. The present study aimed to analyze the relationship between skin primo nodes and acupoints through changes in the expression of tissue concentrations of skin primo nodes. Analysis of this skin primo node confirmed that the skin primo node after acupuncture had a significantly higher concentration of sulfur and calcium than found in normal skin. And the significant pO2 in the skin primo node was confirmed by measuring pO2 using a needle oxygen sensor. Through sulfur, calcium, and pO2 concentration values of skin primo nodes, we confirmed whether these nodes could be related to acupoint. To understand the clear structure and function of this node, it is necessary to further study through the known properties of acupoints and the function of Primo Vascular System (PVS).

Algoriphagus aquimaris sp. nov., isolated from seashore sand.

Strain F21T, a marine, aerobic, Gram-negative, rod-shaped bacterium, was isolated from seashore sand sampled in Pohang, Republic of Korea. Cells of strain F21T were non-motile, catalase-positive, oxidase-positive, non-spore-forming and formed pinkish-red colonies on marine agar. The strain grew optimally at 37°C, pH 7 and in the presence of 2-3 % NaCl (w/v). Analysis of the 16S rRNA gene sequence of strain F21T revealed that it belonged to the genus Algoriphagus, family Cyclobacteriaceae, with similarity values of 98.1 and 96.8 % to Algoriphagus marincola DSM 16067T and Algoriphagus ornithinivorans IMSNU 14014T, respectively. When comparing the genome sequence of F21 T with those of the type strains of six species of the genus Algoriphagus, the values obtained were below the thresholds for analyses of average nucleotide identity (71.8-92.7 %) and in silico DNA-DNA hybridization using the Genome-to-Genome Distance Calculator (14.7-75.2 %). The DNA G+C content of strain F21T was 42.0 mol%. The chemotaxonomic characteristics of F21T included MK-7 as the predominant isoprenoid quinone, iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) as major cellular fatty acids, and phosphatidylcholine and phosphatidylethanolamine as major polar lipids. On the basis of phenotypic and chemotaxonomic properties, phylogenetic distinctiveness, and genomic data, we named strain F21T as Algoriphagus aquimaris sp. nov. and proposed that strain F21T (=KEMB 2250-007T= KCTC 72106T=JCM 33187T) in the genus Algoriphagus represents a novel species.

Western Medicine Versus Eastern Medicine: Do Both Have a Common Root, Scientific Background, and Worldwide Recognition?

This review is designed to initiate a discussion we believe is necessary for the biomedical community, because of some recent evidences for existing of a new body anatomical system, or the primo vascular system (PVS), which could be the missing link in the scientific explanation of the unknown mechanism of action of acupuncture. Some important questions for the medical society, (eg, "What is the main source of the mistrust of Western medicine toward traditional Oriental medicine and could it be overcome?" or "Is the PVS a real one and what is its distribution, formation, and function?" or "Are there scientific proofs for intimate relationships of the PVS with meridian system and whether the PVS would be the physical basis of meridians?") are deeply studied and appropriately answered. Various pieces of knowledge are now combined to achieve a better understanding and to provide an acceptable explanation about the functions of such new system and to explain the functional path used by traditional Eastern medicine to cure diseases. Some possibilities to use this PVS for development of some innovative therapies to treat some diseases are also discussed (eg, pharmacopuncture as a new innovative drug delivery method that combines acupuncture therapy with medication by injecting pharmacological substances into target acupoints).

Ruegeria lutea sp. nov., isolated from marine sediment, Masan Bay, South Korea.

A Gram-stain-negative, non-motile, mesophilic, short rod-shaped, aerobic bacterium designated as 318-1T was isolated from a marine sediment collected from Masan Bay, South Korea. Strain 318-1T grew optimally at pH 6-7, at 30 °C and in the presence of 2-3 % (w/v) NaCl, tolerant of up to 8 % (w/v) NaCl, and accumulated poly-ß-hydroxybutyrate (PHB). A comparative analysis of 16S rRNA gene sequences revealed that strain 318-1T formed a distinct phyletic lineage in the genus Ruegeria (family Rhodobacteraceae, class Alphaproteobacteria) and showed high sequence similarity to Ruegeria halocynthiae DSM 27839T (96.5 %) and Shimia haliotis DSM 28453T (96.3 %). Comparing the genome sequence of 318-1T with those of the type strains of seven species of the genus Rugeria and two species of the genus Shimia, the values obtained were below the thresholds with analysis of average nucleotide identities (ANI, 71.6-76.8 %) and in silico DNA-DNA hybridisation, Genome-to-Genome Distance Calculator (GGDC, 18.5-20.6 %). The DNA G+C content was 65.75 mol%. Chemotaxonomic data [predominant quinone ubiquinone Q10; polar lipid profile consisting of major compounds phosphatidylcholine (PC), phosphatidylglycerol (PG), an unidentified aminolipid and an unidentified lipid; major fatty acids summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c)] supported the affiliation of strain 318-1T to the genus Ruegeria. Genomic, chemotaxonomic, and phenotypic differentiation of strain 318-1T from the members of the genus Ruegeria support it as a novel species. On the basis of the results in this study, a novel species, Ruegeria lutea sp. nov., is proposed. The type strain is 318-1T (=JCM 30927T=KEMB 7306-525T=KCTC 72105T).

Numerical modeling of the effect of multiple incoherent layers in Cu(In,Ga)Se2 solar cells based on the equispaced thickness averaging method.

We investigate the effect of multiple incoherent layers on the optical characteristics of Cu(In,Ga)Se2 (CIGS) solar cells, based on the equispaced thickness averaging method (ETAM). The studied multiple incoherent layers consist of a glass cover layer, surface flattening layer, and transparent conducting layer, whose respective thicknesses are larger than the coherence length of sunlight (∼0.6 µm). An independent equispaced thickness is added to each incoherent layer and the coherent simulation results, obtained by the finite element method, are averaged over a combination of the equispaced thicknesses. By applying the proposed method, we calculated the reflectance spectra in planar and surface-textured CIGS solar cells. Considering the planar structure, the calculation results based on the ETAM are in good agreement with the exact analytical solution based on the generalized transfer matrix method. The statistical deviation from the exact solution was calculated with respect to the number of the equispaced thicknesses in each incoherent layer. When only four equispaced thicknesses are used, the calculated deviation from the exact solution rapidly decreases to 1% for planar and 10% for surface-textured CIGS solar cells, which demonstrates that the effect of the multiple incoherent layers can be efficiently calculated based on the ETAM in thin-film solar cells.

Effect of Coronary Artery Calcification Score by Lifestyle and Correlation With Coronary Artery Stenosis by Multidetector Computed Tomography.

OBJECTIVE: This study examined the effect of coronary artery calcification score by lifestyle and correlation with coronary artery stenosis in persons who underwent coronary artery computed tomography (CT) angiography among health examinees for heart diseases in Korea. METHODS AND MATERIALS: The study included 506 subjects (256 men and 250 women) who underwent coronary artery CT angiography among health examines for heart diseases at the Incheon Branch of the Korea Association of Health Promotion between January 2, 2014, and December 31, 2014. The demographical variables of the subjects were determined by frequency analysis, and the difference by sex was compared and analyzed using χ independence test. Independent 2-sample t test was performed to determine any difference in main factors by coronary artery calcification. RESULTS: According to the results, 175 (34.6%) had calcification, men showed statistically higher scores than women, and calcification seemed higher in those who were older, taller, heavier, and thicker in waist. Regarding blood pressure, calcification was shown if contraction phase and relaxation blood pressure was higher, blood sugar before meal was higher, and neutral fat was higher. By lifestyle, calcification seemed to be higher in those with more alcohol drinking per week, long past smoking years, and higher smoking amount per day in the past and present. In addition, coronary artery stenosis rate showed statistical correlation with calcification from the left anterior descending artery, right coronary artery, left circumflex artery, and left main coronary artery in sequence. CONCLUSIONS: In conclusion, coronary artery calcification score CT is deemed to be a suitable method for the estimation of coronary artery stenosis with short examination time, low radiation exposure, and noninvasive method.

The effects of milk intake and whole-body vibration exercise on bone mineral density in elderly women in nursing homes.

[Purpose] This study was designed to investigate the effects of lactose-free milk intake and whole-body vibration exercises on bone density in elderly female nursing home residents who had difficulty exercising outdoors and had not consumed milk. [Subjects and Methods] Twenty seven elderly women aged 70 or older from 3 nursing homes located in Incheon, Korea participated in the study. The experimental group (n=13) carried out whole-body vibration exercises and drank lactose-free milk, while the control group (n=14) continued to live their ordinary nursing home lives. Weight, BMI, T-scores, and Z-scores were compared between the experimental and control groups after 12 weeks. [Results] The comparison of changes in weight and BMI in the control group before and after the 12-week experiment found no statistically significant differences. However, bone mineral density was significantly different, with the T-score significantly decreasing from -2.99 to -3.48 and the Z-score decreasing from -1.87 to -2.58. The other comparisons of physical changes in the control group before and after the 12-week experiment found no statistical significance. [Conclusion] The results indicate that regular consumption of lactose-free milk and performing whole-body vibration exercises can delay the progression of bone density loss in older adults in nursing homes; adequate exercise and calcium intake could eventually help prevent fractures.

A mutation profile for top-k patient search exploiting Gene-Ontology and orthogonal non-negative matrix factorization.

MOTIVATION: As the quantity of genomic mutation data increases, the likelihood of finding patients with similar genomic profiles, for various disease inferences, increases. However, so does the difficulty in identifying them. Similarity search based on patient mutation profiles can solve various translational bioinformatics tasks, including prognostics and treatment efficacy predictions for better clinical decision making through large volume of data. However, this is a challenging problem due to heterogeneous and sparse characteristics of the mutation data as well as their high dimensionality. RESULTS: To solve this problem we introduce a compact representation and search strategy based on Gene-Ontology and orthogonal non-negative matrix factorization. Statistical significance between the identified cancer subtypes and their clinical features are computed for validation; results show that our method can identify and characterize clinically meaningful tumor subtypes comparable or better in most datasets than the recently introduced Network-Based Stratification method while enabling real-time search. To the best of our knowledge, this is the first attempt to simultaneously characterize and represent somatic mutational data for efficient search purposes. AVAILABILITY: The implementations are available at: https://sites.google.com/site/postechdm/research/implementation/orgos. CONTACT: sael@cs.stonybrook.edu or hwanjoyu@postech.ac.kr SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Eu(2+)-Activated Alkaline-Earth Halophosphates, M5(PO4)3X:Eu(2+) (M = Ca, Sr, Ba; X = F, Cl, Br) for NUV-LEDs: Site-Selective Crystal Field Effect.

Eu(2+)-activated M5(PO4)3X (M = Ca, Sr, Ba; X = F, Cl, Br) compounds providing different alkaline-earth metal and halide ions were successfully synthesized and characterized. The emission peak maxima of the M5(PO4)3Cl:Eu(2+) (M = Ca, Sr, Ba) compounds were blue-shifted from Ca to Ba (454 nm for Ca, 444 nm for Sr, and 434 nm for Ba), and those of the Sr5(PO4)3X:Eu(2+) (X = F, Cl, Br) compounds were red-shifted along the series of halides, F → Cl → Br (437 nm for F, 444 nm for Cl, and 448 nm for Br). The site selectivity and occupancy of the activator ions (Eu(2+)) in the M5(PO4)3X:Eu(2+) (M = Ca, Sr, Ba; X = F, Cl, Br) crystal lattices were estimated based on theoretical calculation of the 5d → 4f transition energies of Eu(2+) using LCAO. In combination with the photoluminescence measurements and theoretical calculation, it was elucidated that the Eu(2+) ions preferably enter the fully oxygen-coordinated sites in the M5(PO4)3X:Eu(2+) (M = Ca, Sr, Ba; X = F, Cl, Br) compounds. This trend can be well explained by "Pauling's rules". These compounds may provide a platform for modeling a new phosphor and application in the solid-state lighting field.

Effects of High-Intensity-Focused Ultrasound Treatment on Benign Uterine Tumor.

In this study, the effects of high-intensity-focused ultrasound (HIFU) treatment on benign uterine tumor patients were examined. A total of 333 patients diagnosed with fibroids or adenomyosis using diagnostic sonography, treated with HIFU between February 4, 2010 and December 29, 2014 at a hospital in Korea, and followed up for three or six months were selected for this study. Their benign uterine tumor volume was measured, and the effects of HIFU treatment on the volume were analyzed according to age, disease, fertility, and treatment duration. The volume of benign tumors of the uterus changed by age in all age groups after conducting HIFU treatment for 3 and 6 months, respectively. The rate of decrease in individuals' in their twenties was the largest, at 64.9%. When the decreasing volume of benign tumors of the uterus was analyzed by type of disease, the treatment efficacy for adenomyosis was the best, with a decrease of 164.83 cm(3) after 6 months. Myoma had the fastest decreasing rate, at 68.5%. When evaluated on the basis of fertility, the volume of benign tumors of the uterus continued to decrease until 6 months after completing all procedures. The volume has continued to decrease for 6 months after all procedures. This study showed that HIFU treatments for uterine fibroid and adenomyosis is an effective non-invasive therapy via reducing the benign uterine tumor volume. Therefore, the HIFU method might replace other conventional treatment methods.

Restoration of paclitaxel resistance by CDK1 intervention in drug-resistant ovarian cancer.

Epithelial ovarian cancer (EOC) commonly acquires resistance to chemotherapy, and this is the major obstacle to the better prognosis. Elucidating the molecular targets altered by chemotherapy is critically required to understand and overcome drug resistance. As a drug combination including paclitaxel is a prevalent prescription for treatment of EOC, to uncover gene expression altered in paclitaxel-resistant EOC, we analyzed multidirectional microarray profiles in both EOC cell lines and patients with paclitaxel resistance. Cyclin-dependent kinase 1 (CDK1) was found to be a potential target of transcription factors to regulate paclitaxel resistance. As a result of the subsequent pharmacogenomics analysis, CDK1 inhibitor alsterpaullone was also indicated as a promising chemical that may be used in combinatorial therapies to reverse paclitaxel-induced chemoresistance. Although a CDK1 inhibitor has the potential to kill cancer cells, short-term treatment over 2 weeks at sublethal doses effectively induced cell death only upon additional treatment with paclitaxel. A prominent reduction in the tumor growth rate was observed upon paclitaxel subsequent to alsterpaullone treatment in EOC xenograft model. Thus, we suggest that inhibition of CDK1 with alsterpaullone may be a novel therapeutic method to reverse paclitaxel-induced resistance in ovarian cancer cells.

Evaluation of automatic exposure control system chamber for the dose optimization when examining pelvic in digital radiography.

We found a way to optimize the image quality and reduce the exposure dose of patients through the proper activity combination of the automatic exposure control system chamber for the dose optimization when examining the pelvic anteroposterior side using the phantom of the human body standard model. We set 7 combinations of the chamber of automatic exposure control system. The effective dose was yielded by measuring five times for each according to the activity combination of the chamber for the dose measurement. Five radiologists with more than five years of experience evaluated the image through picture archiving and communication system using double blind test while classifying the 6 anatomical sites into 3-point level (improper, proper, perfect). When only one central chamber was activated, the effective dose was found to be the highest level, 0.287 mSv; and lowest when only the top left chamber was used, 0.165 mSv. After the subjective evaluation by five panel members on the pelvic image was completed, there was no statistically meaningful difference between the 7 chamber combinations, and all had good image quality. When testing the pelvic anteroposterior side with digital radiography, we were able to reduce the exposure dose of patients using the combination of the top right side of or the top two of the chamber.

Human cytomegalovirus clinical strain-specific microRNA miR-UL148D targets the human chemokine RANTES during infection.

The human cytomegalovirus (HCMV) clinical strain Toledo and the attenuated strain AD169 exhibit a striking difference in pathogenic potential and cell tropism. The virulent Toledo genome contains a 15-kb segment, which is present in all virulent strains but is absent from the AD169 genome. The pathogenic differences between the 2 strains are thought to be associated with this additional genome segment. Cytokines induced during viral infection play major roles in the regulation of the cellular interactions involving cells of the immune and inflammatory systems and consequently determine the pathogenic outcome of infection. The chemokine RANTES (Regulated on activation, normal T-cell expressed and secreted) attracts immune cells during inflammation and the immune response, indicating a role for RANTES in viral pathogenesis. Here, we show that RANTES was downregulated in human foreskin fibroblast (HFF) cells at a later stage after infection with the Toledo strain but not after infection with the AD169 strain. miR-UL148D, the only miRNA predicted from the UL/b' sequences of the Toledo genome, targeted the 3'-untranslated region of RANTES and induced degradation of RANTES mRNA during infection. While wild-type Toledo inhibited expression of RANTES in HFF cells, Toledo mutant virus in which miR-UL148D is specifically abrogated did not repress RANTES expression. Furthermore, miR-UL148D-mediated downregulation of RANTES was inhibited by treatment with a miR-UL148D-specific inhibitor designed to bind to the miR-UL148D sequence via an antisense mechanism, supporting the potential value of antisense agents as therapeutic tools directed against HCMV. Our findings identify a viral microRNA as a novel negative regulator of the chemokine RANTES and provide clues for understanding the pathogenesis of the clinical strains of HCMV.

Effect of long-term supplementation of low molecular weight chitosan oligosaccharide (GO2KA1) on fasting blood glucose and HbA1c in db/db mice model and elucidation of mechanism of action.

BACKGROUND: Type 2 diabetes is a serious problem for developed countries. Prevention of prediabetes progression to type 2 diabetes with the use of natural products appears to a cost-effective solution. Previously we showed that enzymatically digested low molecular weight chitosan-oligosaccharide with molecular weight (MW) below 1,000 Da (GO2KA1) has potential for hyperglycemia management. METHODS: In this study we evaluated the effect of long-term supplementation of GO2KA1 on hyperglycemia using a db/db mice model. Additionally, we evaluated the effect of GO2KA1 on sucrase and glucoamylase activities and expression, using the same db/db mice model. RESULTS: After 42 days we observed that GO2KA1 supplementation reduced both the blood glucose level and HbA1c in a similar manner with a known anti-diabetic drug, acarbose. When the sucrase and glucoamylase activities of GO2KA1 and control mice were evaluated using enzymatic assay, we observed that GO2KA1 significantly inhibited sucrase in all 3 parts of the intestine, while glucoamylase activity was significantly reduced only in the middle and lower part. When the sucrase-isomaltase (SI) complex expression on mRNA level was evaluated, we observed that GO2KA1 had minimal inhibitory effect on the upper part, more pronounced inhibitory effect on the middle part, while the highest inhibition was observed on the lower part. Our findings suggest that long-term GO2KA1 supplementation in db/db mice results to significant blood glucose and HbA1c reduction, to levels similar with those of acarbose. Furthermore, our findings confirm previous in vitro observations that GO2KA1 has inhibitory effect on carbohydrate hydrolysis enzymes, namely sucrase, maltase and SI complex. CONCLUSIONS: Results from this study provide a strong rationale for the use of GO2KA1 for type 2 diabetes prevention, via inhibition of carbohydrate hydrolysis enzymes. Based on the findings of this animal trial, clinical trials will be designed and pursued.

Harnessing CRISPR-Cas adaptation for RNA recording and beyond.

Prokaryotes encode clustered regularly interspaced short palindromic repeat (CRISPR) arrays and CRISPR-associated (Cas) genes as an adaptive immune machinery. CRISPR-Cas systems effectively protect hosts from the invasion of foreign enemies, such as bacteriophages and plasmids. During a process called 'adaptation', non-self-nucleic acid fragments are acquired as spacers between repeats in the host CRISPR array, to establish immunological memory. The highly conserved Cas1-Cas2 complexes function as molecular recorders to integrate spacers in a time course manner, which can subsequently be expressed as crRNAs complexed with Cas effector proteins for the RNAguided interference pathways. In some of the RNA-targeting type III systems, Cas1 proteins are fused with reverse transcriptase (RT), indicating that RT-Cas1-Cas2 complexes can acquire RNA transcripts for spacer acquisition. In this review, we summarize current studies that focus on the molecular structure and function of the RT-fused Cas1-Cas2 integrase, and its potential applications as a directional RNA-recording tool in cells. Furthermore, we highlight outstanding questions for RT-Cas1-Cas2 studies and future directions for RNA-recording CRISPR technologies. [BMB Reports 2024; 57(1): 40-49].

Characteristics of the New Mast Cell-Rich Nodal Structure in the Rat Skin Surface.

Background: : Acupuncture, practiced for millennia, lacks a clear anatomical definition for acupoints. A prevailing theory suggests that acupoints overlap with skin areas with higher mast cell density. Skin spots stained with intravenously infused Evans blue (EB), indicative of neurogenic inflammation, have recently been posited as acupoints in rats. Objectives: : To demonstrate the concordance between EB-reactive skin spots and mast cell-enriched acupoints. Methods: : We employed staining and RNA-seq analysis to delineate the morphological characteristics and gene expression profiles of EB-reactive skin spots in rats. Results: : EB infusion revealed a novel nodal structure on the rat skin surface, visible to the naked eye, with dimensions of approximately 1 mm in both diameter and height. Around 30 such nodes were identified on one side of the abdominal area, spaced roughly 3 mm apart, excluding the linea alba. RNA-seq analysis indicated that the gene expression patterns within these nodes markedly differed from both non-nodal skin areas and lymph nodes. Histological examination using toluidine blue revealed a significantly greater mast cell count in the nodes than in non-nodal skin regions. Additionally, the nodes stained positively with Alcian blue and Hemacolor, reagents known to mark primo vascular tissues. Conclusion: : Our findings suggest that EB-reactive nodes are indeed rich in mast cells. Further research is warranted to establish these skin nodes as surface primo nodes.