The extracellular matrix protein EFEMP2 is involved in the response to VHSV infection in the olive flounder Paralichthys olivaceus

The EGF-containing fibulin-like extracellular matrix protein 2 (EFEMP2) is involved in connective tissue development, elastic fiber formation, and tumor growth. In this study, we characterized the cDNA of EFEMP2 (PoEFEMP2), a member of the fibulin family of ECM proteins, in the olive flounder Paralichthys olivaceus. The coding region of PoEFEMP2 encodes a protein that contains six calcium-binding EGF-like (EGF-CA) domains and four complement Clr-like EGF-like (cEGF) domains. PoEFEMP2 shows 67.51-96.77 % similarities to orthologs in a variety of fish species. PoEFEMP2 mRNA was detected in all tissues examined; the highest levels of PoEFEMP2 mRNA expression were observed in the heart, testis, ovary and muscle. The PoEFEMP2 mRNA level increases during early development. In addition, the PoEFEMP2 mRNA level increased at 3 h post-infection (hpi) and decreased from 6 to 48 hpi in flounder Hirame natural embryo (HINAE) cells infected with viral hemorrhagic septicemia virus (VHSV). Disruption of PoEFEMP2 using the clustered regularly interspaced short palindromic repeats/CRISPR-associated-9 (CRISPR/Cas9) system resulted in a significant upregulation of VHSV G mRNA levels and immune-related genes expression in knockout cells. These findings implicate PoEFEMP2 in antiviral responses in P. olivaceus.

Quality Properties and Flavor-Related Components of Beef Longissimus Lumborum Muscle from Four Korean Native Cattle Breeds

This study was carried out to assess the quality properties, components associated with taste and aroma of beef as a function of breed. For this purpose, steers from four Korean native cattle breeds: Hanwoo (n=10), Chikso (n=10), black Hanwoo (n=12, BHW) and Jeju black cattle (n=12, JBC) were used. The steers all were raised under identical conditions and finished at a similar age of around 30-months old. Following 24 h of slaughter, all longissimus lumborum muscles were collected and used for analysis of meat quality, fatty acids, and flavor-related components (metabolic compounds, free amino acids, and aroma volatiles). The Hanwoo presented a significantly higher intramuscular fat content (IMF, 22.85%) than the BHW (11.78%), Chikso (9.25%), and JBC (9.14%; p<0.05). The meat of Hanwoo breed showed lighter and redder color, and lower shear force value (p<0.05). The JBC presented a "healthier" fatty acid profiles as it had a higher total unsaturated fatty acids content (p<0.05). With regard to flavor-related components, Hanwoo also had higher total contents of free amino acids and metabolites associated with umami and sweet tastes, and fat-derived volatile compounds (aldehydes, alcohols, and ketones) associated with fatty aroma. It may be concluded that there was a considerable difference in the meat quality properties among breeds. The variations of IMF content and flavor-related components may be the main factors contributing to the typical flavors of beef among the four Korean native cattle breeds.

Type VI Collagen Deficiency Causes Enhanced Periodontal Tissue Destruction

The periodontal ligament (PDL) is a fibrillar connective tissue that lies between the alveolar bone and the tooth and is composed of highly specialized extracellular matrix (ECM) molecules and a heterogeneous population of cells that are responsible for collagen formation, immune response, bone formation, and chewing force sensation. Type VI collagen (COL6), a widely distributed ECM molecule, plays a critical role in the structural integrity and mechanical properties of various tissues including muscle, tendon, bone, cartilage, and skin. However, its role in the PDL remains largely unknown. Our study shows that deficiency of COL6 impairs PDL fibrillogenesis and exacerbates tissue destruction in ligature-induced periodontitis (LIP). We found that COL6-deficient mice exhibited increased bone loss and degraded PDL in LIP and that fibroblasts expressing high levels of Col6α2 are pivotal in ECM organization and cell-ECM interactions. Moreover, COL6 deficiency in the PDL led to an increased number of fibroblasts geared toward the inflammatory response. We also observed that cultured COL6-deficient fibroblasts from the PDL exhibited decreased expression of genes related to collagen fiber turnover and ECM organization as well as migration and proliferation. Our findings suggest that COL6 plays a crucial role in the PDL, influencing fibroblast function in fibrillogenesis and affecting the immune response in periodontitis. These insights advance our understanding of the molecular mechanisms underlying PDL maturation and periodontal disease.

Paenibacillus hexagrammi sp. nov., a novel bacterium isolated from the gut content of Hexagrammos agrammus

A Gram-stain-positive, aerobic bacterium, designated as YPD9-1T, was isolated from the gut contents of a spotty belly greenling, Hexagrammos agrammus, collected near Dokdo island, South Korea. The rod-shaped cells were oxidase-positive, and catalase-negative. The major cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0, C16 : 0, iso-C16 : 0 and iso-C17: 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and two unidentified lipids. The DNA G+C content was 47.6 mol% and the predominant respiratory quinone was menaquinone MK-7. The 16S rRNA gene sequence of YPD9-1T showed low sequence similarities to species of the genus Paenibacillus, Paenibacillus pocheonensis Gsoil 1138T (97.21 % of sequence similarity), Paenibacillus aestuarii CJ25T (97.12 %) and Paenibacillus allorhizoplanae JJ-42T (96.89 %). The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that YPD9-1T formed a distinct branch among other species of the genus Paenibacillus. The digital DNA-DNA hybridisation, average nucleotide identity, and average amino acid identity values between YPD9-1T and the related species were in the ranges of 15.3-16.2 %, 74.1-78.4 %, and 71.1-71.9 %, respectively, which are below the species cutoff values. On the basis of the results of the polyphasic analysis, we conclude that strain YPD9-1T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus hexagrammi sp. nov. is proposed. The type strain of Paenibacillus hexagrammi is YPD9-1T (=KCTC 43424T =LMG 32988T).

Antifungal activity of aminopyrrolnitrin against Trichophyton verrucosum in a guinea pig model of dermatophytosis

BACKGROUND

Dermatophytosis is a common and major public health concern worldwide. Despite the increasing availability of antifungal drugs, relapses and untreated cases of dermatophyte infections are reported. Therefore, novel antifungal agents are required. Aminopyrrolnitrin (APRN) shows promise for dermatophytosis treatment because of its antifungal activity.

OBJECTIVES

This study aimed to assess the antifungal properties of APRN against Trichophyton verrucosum (T. verrucosum), in both laboratory settings and a guinea pig model.

METHODS

The minimum inhibitory concentrations (MICs) of APRN and enilconazole against T. verrucosum were determined according to the CLSI M38 method. The skins of 16 male guinea pigs were infected with 1.0 × 108 conidia of T. verrucosum and the animals were grouped into sets of four: negative control group (NC) received normal saline; positive control group (PC) received 2 μg/mL of enilconazole; and APRN4 and APRN8 received 4 and 8 μg/mL of APRN, respectively. Clinical, mycological and histological efficacies were measured after 10 days.

RESULTS

The MIC90 of APRN and enilconazole against T. verrucosum was 4 and 2 μg/mL, respectively. The clinical scores of PC, APRN4, and APRN8 were significantly lower than those of NC. Clinical and mycological efficacies were higher for APRN8, APRN4 and PC. No fungi were observed in the skin tissues of APRN4 and APRN8, while fungi were observed in 50% of the PC.

CONCLUSION

APRN showed antifungal activity against T. verrucosum in vitro and in vivo and is a potential candidate for the treatment of dermatophytosis.

Clinical Assessment of Thermotherapy Applications during Hepatectomy and Laparotomy in Sturgeon (Acipenser ruthenus): Impact on Bioparameter Variations Based on Liver Condition

Surgical techniques are gaining attention for treating physical diseases in aquaculture and aquarium fish. Sturgeon is a suitable species for surgical experiments due to its industrial significance. Maintaining homeostasis is crucial during surgical procedures, and the liver plays a major role in immune regulation. High temperature is suggested to improve physiological activity and wound healing. This study investigated differences in hepatectomy sturgeons' tolerance and histopathological responses of internal organs. Moreover, this study investigated the effects of high temperatures on wound healing and hematopoietic recovery in fish undergoing surgical procedures. The liver condition was found to play a pivotal role in the analysis, and cortisol levels were affected by anesthesia. The results showed that high temperature facilitated hematopoietic recovery and wound healing, but excessive induction of physiological activity caused damage. Managing high temperatures and liver conditions induced a remarkable improvement in wound healing. However, anesthesia itself can be a significant stressor for fish, and wound healing requires a greater amount of energy. Further research is needed to understand the stress factors caused by surgical procedures and anesthesia and to promote animal welfare in fishery products.

Physical Properties of Poly(ether-thiourea)-Based Elastomer Formed by Zigzag Hydrogen Bonding and Slidable Cross-Linking

In this study, the effects of zigzag hydrogen bonding and slidable cross-linking on the design of stretchable elastomers were explored. Poly(ether-thiourea) (TU), capable of generating strong zigzag hydrogen bonds without crystallization, was introduced as the main chain in the non-cross-linked region of the developed elastomer. Consequently, the toughness of the TU-based elastomer was 14 times higher than that of elastomers formed using linear poly(ethylene glycol), despite the relatively low molecular weight of TU (∼3k). When a slidable polyrotaxane cross-linker was introduced into the TU-based elastomer, its flexibility became twice as high as that of the rigid polymer cross-linker. Moreover, the mechanical properties of the elastomer were prevented from deterioration against repeated deformation under the limited strain condition of 150%.

Identification of Potential Hazards Associated with South Korean Prawns and Monitoring Results Targeting Fishing Bait

This study detected two potential pathogens, Vibro parahaemolyticus, which causes acute hepatopancreatic necrosis disease (AHPND), and white spot syndrome virus (WSSV), in fishing bait in South Korea. However, their infectious nature was not confirmed, possibly due to the degradation caused by freezing/thawing or prolonged storage under frozen conditions. While infectivity was not confirmed in this study, there is still a significant risk of exposure to these aquatic products. Furthermore, fishing bait and feed should be handled with caution as they are directly exposed to water, increasing the risk of disease transmission. In Australia, cases of WSSV infection caused by imported shrimp intended for human consumption have occurred, highlighting the need for preventive measures. While freezing/thawing is a method for inactivating pathogens, there are still regulatory and realistic issues to be addressed.

Meat Quality Changes in Aged Pork Loin using Jeju Volcanic Scoria Earthenware

This study aimed to investigate changes in the quality of meat aged using Jeju scoria earthenware. Water-holding properties, pH, color, tenderization, fatty acid composition, and free amino acid characteristics of aged pork loin were evaluated to determine the effects of wet and dry (normal and Jeju Scoria) aging methods and aging time (0, 10, 20, 30, and 40 days) on meat quality. The aging methods altered pH and CIE L* after 10 days of aging. However, the aging method did not alter the pH and CIE L* of the aged pork loin after 10 days of aging. The shear force was significantly lower in the Scoria aging method than in the wet aging method after 10 and 20 days of aging. Both the normal and Scoria aging methods increased aging loss compared to the wet aging method, which could be attributed to longer air exposure times of the two non-packaged aging methods than in the packaged aging method. The scoria aging method had significantly higher contents and ratios of saturated (SFA) to mono-unsaturated fatty acids but lower ratios of poly-unsaturated fatty acids to SFA than the wet aging method. The content of most free amino acids significantly increased with aging time, especially those related to the sweet, and umami categories. In summary, this study suggests that the Scoria aging method provides positive aspects of eating quality, such as improvement of meat tenderness and taste, including umami, with minimum changes in the overall meat quality.

Manufacture of antibacterial carbon fiber-reinforced plastics (CFRP) using imine-based epoxy vitrimer for medical application

An antibacterial carbon fiber-reinforced plastics (CFRP) was manufactured based on a vitrimer containing imine groups. A liquid curing agent was prepared to include an imine group in the matrix, and was synthesized without a simple mixing reaction and any purification process. The vitrimer used as the matrix for CFRP was prepared by reacting a commercial epoxy with a synthesized curing agent. The structural and thermal properties of the vitrimer were determined by Fourier transform-infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). In addition, the temperature-dependent behavior of the vitrimer was characterized by stress relaxation, reshaping, and shape memory experiments. The mechanical properties of composites fabricated using vitrimer were fully analyzed by tensile, flexural, short-beam strength, and Izod impact tests and had mechanical properties similar to reference material. Moreover, both the vitrimer and the vitrimer composites showed excellent antibacterial activity against Staphylococcus aureus and Escherichia coil due to the imine group inside the vitrimer. Therefore, vitrimer composites have potential for applications requiring antimicrobial properties, such as medical devices.

Enhancement of Thermomechanical Properties of Sulfur-rich Polymers by Post-Thermal Treatment

Recently, sulfur-rich polymers have been applied in various fields including energy storage, mercury absorption, and infrared (IR) optics. However, sulfur-rich polymers typically exhibit insufficient thermomechanical properties for practical applications. Herein,...

Enterovibrio paralichthyis sp. nov., isolated from the gut of an olive flounder Paralichthys olivaceus

A Gram-stain-negative, facultatively anaerobic, flagellated and coccoid, ovoid or rod-shaped bacterial strain, NIFS-20-8^T, was isolated from the intestine of an olive flounder (Paralichthys olivaceus) from the East Sea, Republic of Korea. The neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strain NIFS-20-8^T fell within the clade comprising the type strains of Enterovibrio species. Strain NIFS-20-8^T exhibited 16S rRNA gene sequence similarities of 97.2 and 97.1 % to the type strains of Enterovibrio nigricans and Enterovibrio norvegicus, respectively, and of 96.6-97.0 % to the type strains of the other Enterovibrio species. The average nucleotide identity and digital DNA-DNA hybridization values between the genomic sequence of strain NIFS-20-8^T and those of the type strains of four Enterovibrio species were 73.8-75.0 and 19.8-21.1 %, respectively. The DNA G+C content of strain NIFS-20-8^T from genomic sequence data was 50.55 mol%. Strain NIFS-20-8^T contained Q-8 as the predominant ubiquinone and summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c), C_16 : 0 and C_18 : 1  ω7c as the major fatty acids. The major polar lipids detected in stain NIFS-20-8^T were phosphatidylethanolamine and phosphatidylglycerol. Distinguishing phenotypic properties, together with phylogenetic and genetic distinctiveness, revealed that strain NIFS-20-8^T is separated from recognized Enterovibrio species. On the basis of the data presented here, strain NIFS-20-8^T is considered to represent a novel species of the genus Enterovibrio, for which the name Enterovibrio paralichthyis sp. nov. is proposed. The type strain is NIFS-20-8^T (= KCTC 82873^T=NBRC 115237^T).

Characterization of TRIM16, a member of the fish-specific finTRIM family, in olive flounder Paralichthys olivaceus

Tripartite motif-containing (TRIM) proteins are conserved throughout the metazoan kingdom, and the TRIM subset finTRIM is highly diversified in fish. We isolated TRIM16 cDNA, a member of the finTRIM family, from the olive flounder Paralichthys olivaceus (PoTRIM16). PoTRIM16 contained a 1,725-bp coding sequence encoding a 574-amino acid polypeptide, which in turn contained a really interesting new gene (RING) finger domain, B-box-type zinc finger (B-BOX), nuclease SbcCD subunit C (SbcC), structural maintenance of chromosome (SMC prok B), and stonustoxin (SNTX) subunit alpha (SPRY-PRY-SNTX). Multiple alignment of related sequences revealed that PoTRIM16 showed 86.63-97.40% identity with fish orthologues, and a phylogenetic tree was constructed of vertebrates. PoTRIM16 mRNA was detected in all tissues examined; levels were highest in the eye and ovary. PoTRIM16 mRNA expression was investigated during early development. Under VHSV infection, PoTRIM16 mRNA was downregulated in the liver of P. olivaceus. This is the first study to characterize fish-specific finTRIM in P. olivaceus, which may play a role in the immune response against virus infection.

Regional Control of Multistimuli-Responsive Structural Color-Switching Surfaces by a Micropatterned DNA-Hydrogel Assembly

Structural colors have advantages compared with chemical pigments or dyes, such as iridescence, tunability, and unfading. Many studies have focused on developing the ability to switch ON/OFF the structural color; however, they often suffer from a simple and single stimulus, remaining structural colors, and target selectivity. Herein, we present regionally controlled multistimuli-responsive structural color switching surfaces. The key part is the utilization of a micropatterned DNA-hydrogel assembly on a single substrate. Each hydrogel network contains a unique type of stimuli-responsive DNA motifs as an additional cross-linker to exhibit swelling/deswelling via stimuli-responsive DNA interactions. The approach enables overcoming the existing limitations and selectively programming the DNA-hydrogel to a decrypted state (ON) and an encrypted state (OFF) in response to multiple stimuli. Furthermore, the transitions are reversible, providing cyclability. We envision the potential of our method for diverse applications, such as sensors or anticounterfeiting, requiring multistimuli-responsive structural color switching surfaces.

The complete mitochondrial genome of Pseudopleuronectes herzensteini

Pseudopleuronectes herzensteini belonging to Pleuronectiformes (family Pleuronectidae) is important in the fishery industry. However, the molecular biology of this valuable fish has hardly been reported. Thus, here we report the complete mitochondrial genome of P. herzensteini. The mitochondrial DNA (mtDNA) of P. herzensteini is 16,719 bp long and contains 13 mitochondrial protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and a putative control region between tRNA-P and tRNA-F distinguished by a single short noncoding region. Phylogenetic analysis using PCGs confirmed that this mtDNA sequence belongs to the family Pleuronectidae. This is the first study reporting the complete mitochondrial genome sequence of P. herzensteini.

A Low-Power Analog Processor-in-Memory-Based Convolutional Neural Network for Biosensor Applications

This paper presents an on-chip implementation of an analog processor-in-memory (PIM)-based convolutional neural network (CNN) in a biosensor. The operator was designed with low power to implement CNN as an on-chip device on the biosensor, which consists of plates of 32 × 32 material. In this paper, 10T SRAM-based analog PIM, which performs multiple and average (MAV) operations with multiplication and accumulation (MAC), is used as a filter to implement CNN at low power. PIM proceeds with MAV operations, with feature extraction as a filter, using an analog method. To prepare the input feature, an input matrix is formed by scanning a 32 × 32 biosensor based on a digital controller operating at 32 MHz frequency. Memory reuse techniques were applied to the analog SRAM filter, which is the core of low power implementation, and in order to accurately grasp the MAC operational efficiency and classification, we modeled and trained numerous input features based on biosignal data, confirming the classification. When the learned weight data was input, 19 mW of power was consumed during analog-based MAC operation. The implementation showed an energy efficiency of 5.38 TOPS/W and was differentiated through the implementation of 8 bits of high resolution in the 180 nm CMOS process.

Printable Self-Activated Liquid Metal Stretchable Conductors from Polyvinylpyrrolidone-Functionalized Eutectic Gallium Indium Composites

Stretchable electronic circuits are critical in a variety of next-generation electronics applications, including soft robots, wearable technologies, and biomedical applications. To date, printable composite conductors comprising various types of conductive fillers have been suggested to achieve high electrical conductance and excellent stretchability. Among them, liquid metal particles have been considered as a viable candidate filler that can meet the necessary prerequisites. However, a mechanical activation process is needed to generate interconnected liquid channels inside elastomeric polymers. In this study, we have developed a chemical strategy of surface-functionalizing liquid metal particles to eliminate the necessity of additional mechanical activation processes. We found that the characteristic conformations of the polyvinylpyrrolidone surrounding eutectic gallium indium particles are highly dependent on the molecular weight of polyvinylpyrrolidone. By virtue of the specific chemical roles of polyvinylpyrrolidone, the as-printed composite layers are highly conductive and stretchable, exhibiting an electrical conductivity approaching 8372 S/cm at 100% strain and an invariant resistance change of 0.92 even at 75% strain after a 60,000 cycle test. The results demonstrate that the self-activated liquid metal-based composite conductors are applicable to traditional stretchable electronics, healable stretchable electronics, and shape-morphable applications.

Nocardioides humilatus sp. nov., isolated from farmland soil in the Republic of Korea

A Gram-stain positive, aerobic, irregularly rod-shaped, non-spore-forming bacterium, designated as BN130099T, was isolated from farmland soil sampled in Goesan-gun, Chungbuk, Republic of Korea. Phylogenetic analysis of its 16S rRNA gene sequence showed that the strain is closely related to Nocardioides pelophilus KACC 19192T with 98.11 % similarity. The DNA G+C content of strain BN130099T was 68.84 mol% (draft genome sequence). The genome sequence of BN130099T displayed key enzymes involved in bioremediation of organic pollutants and biosynthetic clusters of saquayamycin. The strain contained ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan and MK-8(H4) as the major respiratory quinone. The predominant fatty acid was iso-C16 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and phosphatidylinositol. The results of physiological and biochemical characterization allowed the phenotypic differentiation of strain BN130099T from N. pelophilus KACC 19192T. The strain represents a novel species of the genus Nocardioides , for which we propose the name Nocardioides humilatus sp. nov. The type strain is BN130099T (=KCTC 49079T=CCTCC AB 2018135T).

Paenihalocynthiibacter styelae gen. nov., sp. nov., isolated from stalked sea squirt Styela clava

A Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterial strain, MYP1-1^T, was isolated from the intestine of a stalked sea squirt (Styela clava) of the South Sea in the Republic of Korea. The neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain MYP1-1^T clustered with the type strains of Halocynthiibacter species and Pseudohalocynthiibacter aestuariivivens. Strain MYP1-1^T exhibited 16S rRNA gene sequence similarity values of 97.0-97.6 % to the type strains of Halocynthiibacter namhaensis, Halocynthiibacter arcticus and P. aestuariivivens. The phylogenetic tree based on genomic sequences showed that strain MYP1-1^T formed a distinct branch separating it from the type strains of two Halocynthiibacter species and P. aestuariivivens and other taxa. The DNA G+C content of strain MYP1-1^T from its genomic sequence was 55.0 mol%. Strain MYP1-1^T contained Q-10 as the predominant ubiquinone and C_18 : 1  ω7c as the major fatty acid. The major polar lipids of strain MYP1-1^T were phosphatidylcholine, phosphatidylglycerol, one unidentified lipid and one unidentified aminolipid. The differences in fatty acid and polar lipid profiles and other differential phenotypic properties made it reasonable to distinguish strain MYP1-1^T from the genera Halocynthiibacter and Pseudohalocynthiibacter. On the basis of the polyphasic taxonomic investigations, we conclude that strain MYP1-1^T constitutes a new genus and species within the class Alphaproteobacteria, for which the name Paenihalocynthiibacter styelae gen. nov., sp. nov. is proposed. The type strain is MYP1-1^T (=KCTC 82143^T=NBRC 114355^T).

Structural basis for SdgB- and SdgA-mediated glycosylation of staphylococcal adhesive proteins

The initiation of infection of host tissues by Staphylococcus aureus requires a family of staphylococcal adhesive proteins containing serine-aspartate repeat (SDR) domains, such as ClfA. The O-linked glycosylation of the long-chain SDR domain mediated by SdgB and SdgA is a key virulence factor that protects the adhesive SDR proteins against host proteolytic attack in order to promote successful tissue colonization, and has also been implicated in staphylococcal agglutination, which leads to sepsis and an immunodominant epitope for a strong antibody response. Despite the biological significance of these two glycosyltransferases involved in pathogenicity and avoidance of the host innate immune response, their structures and the molecular basis of their activity have not been investigated. This study reports the crystal structures of SdgB and SdgA from S. aureus as well as multiple structures of SdgB in complex with its substrates (for example UDP, N-acetylglucosamine or SDR peptides), products (glycosylated SDR peptides) or phosphate ions. Together with biophysical and biochemical analyses, this structural work uncovered the novel mechanism by which SdgB and SdgA carry out the glycosyl-transfer process to the long SDR region in SDR proteins. SdgB undergoes dynamic changes in its structure such as a transition from an open to a closed conformation upon ligand binding and takes diverse forms, both as a homodimer and as a heterodimer with SdgA. Overall, these findings not only elucidate the putative role of the three domains of SdgB in recognizing donor and acceptor substrates, but also provide new mechanistic insights into glycosylation of the SDR domain, which can serve as a starting point for the development of antibacterial drugs against staphylococcal infections.

Antimicrobial Activity and Action Mechanisms of Arg-Rich Short Analog Peptides Designed from the C-Terminal Loop Region of American Oyster Defensin (AOD)

American oyster defensin (AOD) was previously purified from acidified gill extract of the American oyster, Crassostrea virginica. AOD is composed of 38 amino acids with three disulfide bonds and exhibits strong antimicrobial activity against Gram-positive bacteria as well as significant activity against Gram-negative bacteria. Here, to develop promising peptides into antibiotic candidates, we designed five arginine-rich analogs (A0, A1, A2, A3, and A4), predicted their loop and extended strand/random structures-including nine amino acids and a disulfide bond derived from the C-terminus of AOD-and described their antimicrobial and cytotoxic effects, as well as their modes of action. In our experimental results, the A3 and A4 analogs exhibited potent antimicrobial activity against all test organisms-including four Gram-positive bacteria, six Gram-negative bacteria, and Candida albicans-without cell toxicity. A sequence of experiments, including a membrane permeabilization assay, DNA binding study, and DNA polymerization inhibition test, indicated that the two analogs (A3 and A4) possibly did not act directly on the bacterial membrane but instead interacted with intracellular components such as DNA or DNA amplification reactions. AOD analogs also showed strong bacterial inhibition activity in the plasma environment. In addition, analog-treated microbial cells clearly exhibited membrane disruption, damage, and leakage of cytoplasmic contents. Collectively, our results suggest that two analogs, A3 and A4, have potent antimicrobial activity via DNA interaction and have the potential for development into novel antimicrobial agents.

Crystal structures of human NSDHL and development of its novel inhibitor with the potential to suppress EGFR activity

NAD(P)-dependent steroid dehydrogenase-like (NSDHL), an essential enzyme in human cholesterol synthesis and a regulator of epidermal growth factor receptor (EGFR) trafficking pathways, has attracted interest as a therapeutic target due to its crucial relevance to cholesterol-related diseases and carcinomas. However, the development of pharmacological agents for targeting NSDHL has been hindered by the absence of the atomic details of NSDHL. In this study, we reported two X-ray crystal structures of human NSDHL, which revealed a detailed description of the coenzyme-binding site and the unique conformational change upon the binding of a coenzyme. A structure-based virtual screening and biochemical evaluation were performed and identified a novel inhibitor for NSDHL harboring suppressive activity towards EGFR. In EGFR-driven human cancer cells, treatment with the potent NSDHL inhibitor enhanced the antitumor effect of an EGFR kinase inhibitor. Overall, these findings could serve as good platforms for the development of therapeutic agents against NSDHL-related diseases.