Evaluation of Silk Fibroin/Gellan Gum Hydrogels with Controlled Molecular Weight through Silk Fibroin Hydrolysis for Tissue Engineering Application.

Hydrogel is a versatile material that can be manipulated to achieve the desired physicochemical properties, such as stiffness, pore size, and viscoelasticity. Traditionally, these properties have been controlled through parameters such as concentration and pH adjustments. In this study, we focused on exploring the potential of hydrolyzed silk fibroin (HSF) as a molecular weight-modulating agent to control the physicochemical properties of double-composite hydrogels. We developed a synergistic dual-crosslinked hydrogel by combining ionically crosslinked silk fibroin with gellan gum (GG). The hydrolysis of silk fibroin not only enhanced its hydrophilicity but also enabled adjustments in its mechanical properties, including the pore size, initial modulus elasticity, and relaxation time. Moreover, biocompatibility assessments based on cell viability tests confirmed the potential of these hydrogels as biocompatible materials. By highlighting the significance of developing an HSF/GG dual-crosslinked hydrogel, this study contributes to the advancement of novel double-composite hydrogels with remarkable biocompatibility. Overall, our findings demonstrate the capability of controlling the mechanical properties of hydrogels through molecular weight modulation via hydrolysis and highlight the development of a biocompatible HSF/GG dual-crosslinked hydrogel with potential biomedical applications.

A Gellan Gum, Polyethylene Glycol, Hydroxyapatite Composite Scaffold with the Addition of Ginseng Derived Compound K with Possible Applications in Bone Regeneration.

Engineered bone scaffolds should mimic the natural material to promote cell adhesion and regeneration. For this reason, natural biopolymers are becoming a gold standard in scaffold production. In this study, we proposed a hybrid scaffold produced using gellan gum, hydroxyapatite, and Poly (ethylene glycol) within the addition of the ginseng compound K (CK) as a candidate for bone regeneration. The fabricated scaffold was physiochemically characterized. The morphology studied by scanning electron microscopy (SEM) and image analysis revealed a pore distribution suitable for cells growth. The addition of CK further improved the biological activity of the hybrid scaffold as demonstrated by the MTT assay. The addition of CK influenced the scaffold morphology, decreasing the mean pore diameter. These findings can potentially help the development of a new generation of hybrid scaffolds to best mimic the natural tissue.

Survival dynamics of stick insect and the impact of environmental factors on natural fungal infection during the rainy season.

Phasmatodea, commonly known as stick insects, are recognized as noteworthy pests globally, impacting agriculture and forest ecosystems. Among them, the outbreak of Ramulus mikado has emerged as a notable concern in East Asian forests. Recently, Metarhizium phasmatodeae has been identified as utilizing stick insects as hosts. We have observed evidence of this entomopathogenic fungus infecting stick insects. Given the increase in these occurrences during the rainy period, this study investigated the relationship between the survival of R. mikado and the M. phasmatodeae infection during the rainy seasons of 2022 and 2023. We collected stick insects in two representative forests of the Republic of Korea and examined insect survival, fungal infection, and various environmental factors. No infections were detected in specimens collected in June before the rainy season, but from July onwards, both the mortality of R. mikado and the fungal infection substantially increased. By the last sampling date of each year, 75% (2022), 71.4% (2023) of the specimens were infected, and over 90% of the total individuals succumbed as a result. Fungi isolated from deceased R. mikado were successfully identified as M. phasmatodeae using morphological and taxonomic approaches. Various statistical analyses, including principal component analysis and modeling, revealed a robust association between fungal infection and the survival of stick insects. The results highlight the correlation between mass deaths of stick insects and fungal infection, particularly during the summer rainy season. These findings offer valuable insights for forecasting R. mikado population in the upcoming year and developing effective pest control strategies.

Five new species of Bryaxis Kugelann (Coleoptera, Staphylinidae, Pselaphinae) from Korea and a nomenclatural note on Bryaxismahunkai Löbl.

The genus Bryaxis Kugelann (Goniaceritae: Bythinini) is the most species-rich genus of the subfamily Pselaphinae and is mainly distributed in the Palearctic region. Although previous studies have documented 14 species in the Korean Peninsula, the true diversity, ecology, and immature stages of the genus are still inadequately known. In this study, five new Korean species are described: B.grandinodussp. nov., B.uljinensissp. nov., B.fabaiformissp. nov., B.girinensissp. nov., and B.nemorosussp. nov. Illustrations of the habitus and other morphological details, and a distribution map are provided. In addition, Bryaxisleechanyoungi Nomura & Lee, 1993 is proposed as a new synonym of B.mahunkai Löbl, 1975 based on the original description and illustrations of diagnostic characters.

Development of Gelatin-Based Shape-Memory Polymer Scaffolds with Fast Responsive Performance and Enhanced Mechanical Properties for Tissue Engineering Applications.

Shape-memory polymers (SMPs) can be defined as a reversibly changing form through deformation and recovery by external stimuli. However, there remain application limitations of SMPs, such as complicated preparation processes and slow shape recovery. Here, we designed gelatin-based shape-memory scaffolds by a facile dipping method in tannic acid solution. The shape-memory effect of scaffolds was attributed to the hydrogen bond between gelatin and tannic acid, which acts as the net point. Moreover, gelatin (Gel)/oxidized gellan gum (OGG)/calcium chloride (Ca) was intended to induce faster and more stable shape-memory behavior through the introduction of a Schiff base reaction. The chemical, morphological, physicochemical, and mechanical properties of the fabricated scaffolds were evaluated, and those results showed that the Gel/OGG/Ca had improved mechanical properties and structural stability compared with other scaffold groups. Additionally, Gel/OGG/Ca exhibited excellent shape-recovery behavior of 95.8% at 37 °C. As a consequence, the proposed scaffolds can be fixed to the temporary shape at 25 °C in just 1 s and recovered to the original shape at 37 °C within 30 s, implying a great potential for minimally invasive implantation.

Population genetic structure of a recent insect invasion: a gall midge, Asynapta groverae (Diptera: Cecidomyiidae) in South Korea since the first outbreak in 2008.

Outbreaks of Asynapta groverae, an invasive mycophagous gall midge, in South Korea have been repeatedly reported since the first occurrence in 2008. This species is a nuisance to residents owing to its mass emergence from newly built and furnished apartments. Here, the levels of genetic diversity, divergence, and structure of invasive A. groverae populations were investigated to understand their ability to survive in novel locations. Population genetic analyses were performed on seven invasive populations, including the first outbreak, sporadically emerged, and two laboratory-isolated (quarantined) populations, using the mitochondrial COI sequences and the ten novel microsatellite markers developed in this study. Non-indigenous A. groverae managed to maintain their populations for 12 years despite decreased genetic polymorphisms resulting from multiple incidences of founder effects by a small number of colonists. Additionally, the advantageous sustainability of A. groverae in the particle boards from which they emerge suggests that human-mediated dispersal is plausible, which may allow for the successful spread or invasion of A. groverae to new locations. This study is one of the few examples to demonstrate that an insect species successfully invaded new regions despite exhibiting decreased genetic diversity that was maintained for a decade. These findings indicate that the high genetic diversity of the initial founding population and asexual reproduction would contribute to the successful invasion of A. groverae in novel environments.

Hexatoma crane flies (Diptera, Limoniidae) of Korea.

Hexatoma Latreille, 1809 is a large genus of short-palped crane flies with a worldwide distribution. Accounting for more than 60 percent of global species, 362 extant species occur in Asia. Prior to our study, Hexatoma crane flies on the Korean Peninsula (both the Democratic People's Republic of Korea and the Republic of Korea) had been studied for 90 years starting in 1930, but only three species had been recorded, with one of them being a misidentification. This study adds six species to the fauna of the Korean Peninsula, all of which belong to the subgenus H. (Eriocera) Macquart, 1838. General information on genus and subgenus morphological characters is presented in this paper, with a redescription of each species based on Korean specimens, as well as illustrations of both sexes, the elevation range, the period of activity, habitat information, general distribution, and a distribution map for the Korean Peninsula. Three species H. (E.) ilwola Podenas, sp. nov., H. (E.) pianigra Podenas, sp. nov. and H. (E.) serenensis Podenas, sp. nov. are described as new to science. Hexatoma (E.) lygropis (Alexander, 1920) is deleted from the Korean species list as a misidentification. This publication is a continuation of our previous work on short-palped crane flies (Limoniidae) from Korea.

Review of the Korean Species of the Genus Edaphus Motschulsky (Coleoptera, Staphylinidae) with Description of Four New Species.

The cosmopolitan euaesthetine genus, Edaphus Motschulsky, 1857, with about 90 Palaearctic species, was formerly known by a single species, E. koreanus Puthz, 2011, of which 2 specimens were collected in the southern part of the Korean Peninsula. In this paper, the knowledge of the Korean Edaphus fauna is expanded to include six species, including four described here based on a rich material collected in recent years. A key to all six species of Korean Edaphus, illustration of the habitus and diagnostic characters, and a distribution map are provided.

Fast stress relaxing gellan gum that enhances the microenvironment and secreting function of bone mesenchymal stem cells.

This study shows tunable stress relaxing gellan gum (GG) hydrogel for enhanced cell growth and regenerative medicine. The molecular weight and physical crosslinking density of GG were tuned and characterized with physicochemical analysis and mechanical tests. The result showed that a decrease in the molecular weight of the GG correlated with a decline in the mechanical properties but faster stress relaxing character. We also discovered that human-derived bone marrow stem cells (hBMSC) showed active viability, proliferation, and remodeling in the fast stress relaxing GG hydrogel. In particular, hBMSC showed an enhanced release profile of growth factors and exosomes (Exo) in the fast stress relaxing GG hydrogel. The secretome obtained from hBMSC embedded in hydrogel exhibited similar cytotoxicity and wound healing properties to that of secretome extracted from hBMSC cultured in a tissue culture plate (TCP) a standard culture condition. Thus, this work demonstrates the potential of fast stress relaxing GG hydrogels for medical application.

Tipula (Vestiplex) crane flies (Diptera, Tipulidae) of Korea.

The Korean species of Tipula (Vestiplex) Bezzi, 1924 crane flies are taxonomically revised. Five species are recognized. Tipula (V.) coquillettiana Alexander, 1924, T. (V.) kuwayamai Alexander, 1921, T. (V.) tchukchi Alexander, 1934, and T. (V.) verecunda Alexander, 1924 are newly recorded from the Korean Peninsula, and T. (V.) serricauda Alexander, 1914 was previously recorded. The larva of T. (V.) serricauda is described and illustrated, and the larvae of the subgenus T. (Vestiplex) are divided into four groups based on spiracular lobe morphology. An identification key, redescriptions, and illustrations of Korean T. (Vestiplex) adults and grouping of known larvae are presented.

Revision of Korean species of the genus Batriscenellus Jeannel (Staphylinidae, Pselaphinae, Batrisitae) with description of one new species.

The genus Batriscenellus Jeannel, 1958 (type species: Batrisus fragilis Sharp) includes 35 species and is known from South Korea, China, Japan, Russia, and India. Three species, B. vicarius, B. auritus, and B. orientalis have been documented from the Korean Peninsula. One additional species, Batriscenellus koreanus sp. nov., is described as new. Redescriptions of the Korean species, a species key, illustration of habitus, and diagnostic characters are provided.

Recent Technologies for Amorphization of Poorly Water-Soluble Drugs.

Amorphization technology has been the subject of continuous attention in the pharmaceutical industry, as a means to enhance the solubility of poorly water-soluble drugs. Being in a high energy state, amorphous formulations generally display significantly increased apparent solubility as compared to their crystalline counterparts, which may allow them to generate a supersaturated state in the gastrointestinal tract and in turn, improve the bioavailability. Conventionally, hydrophilic polymers have been used as carriers, in which the amorphous drugs were dispersed and stabilized to form polymeric amorphous solid dispersions. However, the technique had its limitations, some of which include the need for a large number of carriers, the tendency to recrystallize during storage, and the possibility of thermal decomposition of the drug during preparation. Therefore, emerging amorphization technologies have focused on the investigation of novel amorphous-stabilizing carriers and preparation methods that can improve the drug loading and the degree of amorphization. This review highlights the recent pharmaceutical approaches utilizing drug amorphization, such as co-amorphous systems, mesoporous particle-based techniques, and in situ amorphization. Recent updates on these technologies in the last five years are discussed with a focus on their characteristics and commercial potential.

Five new species of the genus Pholcus Walckenaer (Araneae: Pholcidae) from South Korea.

Although the high level of species diversity within the Pholcus phungiformes-group (Araneae: Pholcidae) in the Korean Peninsula has been recognized recently, taxonomic studies, including new species discovery, have not been conducted in western regions of South Korea. In this study, five additional species belonging to the Pholcus phungiformes-group discovered from Seoul and surrounding areas are described as new, viz., Pholcus seoulensis Lee Lee, sp. nov. Pholcus suraksanensis Lee Lee, sp. nov., Pholcus incheonensis Lee Lee, sp. nov., Pholcus seokmodoensis Lee Lee, sp. nov. and Pholcus chilgapsanensis Lee Lee, sp. nov. Detailed descriptions and geographic distributions are provided with accompanying photographs.

New record of the genus Typhlocolenis Hoshina, 2008 (Coleoptera, Leiodidae) from South Korea with a key to the species.

This is the first record of the genus Typhlocolenis Hoshina, 2008 (Coleoptera, Leiodidae, Leiodinae, Pseudoliodini) in South Korea. Two new Korean species are described, under the names T. sillaensis sp. nov. and T. jejudoensis sp. nov. As a result of this study, the number of Typhlocolenis species is now five. A key to the species of the genus is provided.

New species of Lipsothrix (Diptera: Limoniidae) from South Korea.

Lipsothrix jiri Podenas, sp. nov. from South Korea is described and illustrated. It is the second species of Lipsothrix Loew, 1873 recorded so far from the Korean Peninsula. The new species has dark brown dorsal and yellow ventral surface of the body and abundant macrotrichiae in apical wing cells. Elevation range, period of activity, habitat information and a distribution map are presented.

A new species of Elephantomyia crane fly (Diptera, Limoniidae) from Jeju Island, South Korea.

A new species of crane fly (Diptera, Limoniidae), Elephantomyia (Elephantomyia) hallasana Podenas & Podeniene, sp. nov., from Jeju Island, South Korea is described. Adult and larval characters are illustrated. Elephantomyia (E.) hallasanasp. nov. is the only species of the genus Elephantomyia Osten Sacken, 1860 recorded from Jeju Island, South Korea. Habitat, elevation range, and seasonality data are presented. Distributional notes on E. subterminalis Alexander, 1954 in the Far East of Russia (Khabarovskiy and Primorskiy regions) are discussed. An identification key for all Eastern Palaearctic species of subgenus E. (Elephantomyia) is presented.

New Atypophthalmus (Diptera: Limoniidae) from South Korea.

Two new species of crane flies belonging to the genus Atypophthalmus Brunetti, 1911, A. (Atypophthalmus) kleini Podenas, sp. nov. and A. (Microlimonia) jeju Podenas Podeniene, sp. nov. collected in South Korea in 2017 and 2019 are described and illustrated. Larvae and female pupa for A. (Microlimonia) jeju sp. nov. are described. The pupa for the subgenus A. (Microlimonia) is described for the first time. An updated list and key for adults of all Korean Atypophthalmus are presented.

New Lipsothrix (Diptera: Limoniidae) from Korea.

Lipsothrix odaesana Podenas Petersen, sp. nov. from South Korea is described and illustrated. It is the only species of Lipsothrix Loew, 1873 recorded so far from the Korean Peninsula. Elevation range, period of activity, habitat information and a distribution map are presented.

Revision of the genus Ptomaphagus Hellwig (Coleoptera, Leiodidae, Cholevinae) from the Russian Far East and the Korean Peninsula.

The conundrum of Ptomaphagus (s. str.) sibiricus Jeannel, 1934 (Coleoptera, Leiodidae, Cholevinae, Ptomaphagini) is solved, and it is redescribed and newly recorded in South Korea. A new species is also described from the Russian Far East: Ptomaphagus (s. str.) hayashii sp. n. Relevant morphological characters of the concerned species are illustrated with colour plates, and their known distributions are mapped.