Correction: Bacterial recognition by PGRP-SA and downstream signalling by Toll/DIF sustain commensal gut bacteria in Drosophila.

[This corrects the article DOI: 10.1371/journal.pgen.1009992.].

Bacterial recognition by PGRP-SA and downstream signalling by Toll/DIF sustain commensal gut bacteria in Drosophila.

The gut sets the immune and metabolic parameters for the survival of commensal bacteria. We report that in Drosophila, deficiency in bacterial recognition upstream of Toll/NF-κB signalling resulted in reduced density and diversity of gut bacteria. Translational regulation factor 4E-BP, a transcriptional target of Toll/NF-κB, mediated this host-bacteriome interaction. In healthy flies, Toll activated 4E-BP, which enabled fat catabolism, which resulted in sustaining of the bacteriome. The presence of gut bacteria kept Toll signalling activity thus ensuring the feedback loop of their own preservation. When Toll activity was absent, TOR-mediated suppression of 4E-BP made fat resources inaccessible and this correlated with loss of intestinal bacterial density. This could be overcome by genetic or pharmacological inhibition of TOR, which restored bacterial density. Our results give insights into how an animal integrates immune sensing and metabolism to maintain indigenous bacteria in a healthy gut.

STAT3 and SOCS3 regulate NG2 cell proliferation and differentiation after contusive spinal cord injury.

NG2 cells, also known as oligodendrocyte progenitors or polydendrocytes, are a major component of the glial scar that forms after spinal cord injury. NG2 cells react to injury by proliferating around the lesion site and differentiating into oligodendrocytes and astrocytes, but the molecular mechanism is poorly understood. In this study, we tested the role of the transcription factor STAT3, and its suppressor SOCS3, in NG2 cell proliferation and differentiation after spinal cord injury. Using knockout mice in which STAT3 or SOCS3 are genetically deleted specifically in NG2 cells, we found that deletion of STAT3 led to a reduction in oligodendrogenesis, while deletion of SOCS3 led to enhanced proliferation of NG2 cells within the glial scar after spinal cord injury. Additionally, STAT3 and SOCS3 were not required for astrogliogenesis from NG2 cells after spinal cord injury. Interestingly, genetic deletion of STAT3 and SOCS3 did not have opposing effects, suggesting that SOCS3 may have targets other than the STAT3 pathway in NG2 cells after spinal cord injury. Altogether, our data show that both STAT3 and SOCS3 play important, yet unexpected, roles in NG2 cell proliferation and differentiation after spinal cord injury.

Mammalian target of rapamycin's distinct roles and effectiveness in promoting compensatory axonal sprouting in the injured CNS.

Mammalian target of rapamycin (mTOR) functions as a master sensor of nutrients and energy, and controls protein translation and cell growth. Deletion of phosphatase and tensin homolog (PTEN) in adult CNS neurons promotes regeneration of injured axons in an mTOR-dependent manner. However, others have demonstrated mTOR-independent axon regeneration in different cell types, raising the question of how broadly mTOR regulates axonal regrowth across different systems. Here we define the role of mTOR in promoting collateral sprouting of spared axons, a key axonal remodeling mechanism by which functions are recovered after CNS injury. Using pharmacological inhibition, we demonstrate that mTOR is dispensable for the robust spontaneous sprouting of corticospinal tract axons seen after pyramidotomy in postnatal mice. In contrast, moderate spontaneous axonal sprouting and induced-sprouting seen under different conditions in young adult mice (i.e., PTEN deletion or degradation of chondroitin proteoglycans; CSPGs) are both reduced upon mTOR inhibition. In addition, to further determine the potency of mTOR in promoting sprouting responses, we coinactivate PTEN and CSPGs, and demonstrate that this combination leads to an additive increase in axonal sprouting compared with single treatments. Our findings reveal a developmental switch in mTOR dependency for inducing axonal sprouting, and indicate that PTEN deletion in adult neurons neither recapitulates the regrowth program of postnatal animals, nor is sufficient to completely overcome an inhibitory environment. Accordingly, exploiting mTOR levels by targeting PTEN combined with CSPG degradation represents a promising strategy to promote extensive axonal plasticity in adult mammals.

Double suicide gene therapy using human neural stem cells against glioblastoma: double safety measures.

With recent advancements in stem cell-based gene therapy, concerns about safety have grown. Stem cell-based gene therapies may pose the risk of immunological problems and oncogenesis. We investigated the feasibility of treating glioblastomas with neural stem cells [(NSCs), HB1.F3 cells] expressing double prodrug enzymes [cytosine deaminase (CD) and tyrosine kinase (TK)] to eliminate the NSCs following treatment for safety purposes. First, the in vitro and in vivo therapeutic efficacies of NSCs engineered with double prodrug enzymes (HB1.F3-CD.TK cells) were compared to cells expressing a single prodrug enzyme (HB1.F3-CD). Second, the degree of safety achieved by NSC elimination was compared with an in vitro viability assay of the NSCs after treatment with the double prodrugs. We further compared the differences in in vivo proliferation of control, single prodrug enzyme and double prodrug enzyme expressing NSCs. HB1.F3-CD.TK cells showed a better or comparable treatment outcome than HB1.F3-CD cells in vitro and in vivo. For safety, HB1.F3-CD.TK cells showed the least viability in vitro after treatment with prodrugs compared to HB1.F3 and HB1.F3-CD cells. Additionally, the in vivo proliferation among the injected NSCs found in the tumor was the smallest for HB1.F3-CD.TK cells. Double-prodrug enzyme-directed gene therapy shows good therapeutic efficacy as well as efficient eradication of the NSCs to ensure safety for clinical applications of stem cell-based gene therapies.

Secondary neurulation of human embryos: morphological changes and the expression of neuronal antigens.

PURPOSE: The morphological changes and expression patterns of neuronal antigens of human embryos, obtained from the therapeutic termination of pregnancy or from surgical procedures, were analyzed in order to characterize the secondary neurulation. METHODS: A total of 21 human embryos from Carnegie stages 12 to 23 and two fetuses in early stages were studied. The markers used for immunohistochemical study were neural cell adhesion molecule (N-CAM), neuronal nuclear antigen (NeuN), neurofilament-associated protein (3A10), synaptophysin, and glial fibrillary acidic protein (GFAP). RESULTS: The formation of the caudal neural tube to the tip of the caudal portion of the embryo was finished at stage 17. The postcloacal gut had completely disappeared at stage 18, and multiple cavities of the caudal neural tube were clearly visible. The caudal portion of the neural tube showed findings suggestive of involution at stage 19. The expression patterns of neuronal antigens were as follows: N-CAM and NeuN showed immunoreactivity at the germinal layer of the spinal cord at stages 17 and 18. Neurofilament-associated protein (3A10) showed persistent immunoreactivity at the caudal cell mass and notochord during the observation period, along with the spinal cord, and the positive reactions were mainly located at the dorsal white matter at stage 17. Synaptophysin showed a weak positive reaction at the caudal cell mass and notochord at stages 13 and 14, evident by staining observed at the spinal cord at stages 15 and 16. There was no definite positive reaction for GFAP. CONCLUSIONS: These characteristic patterns might be helpful for the understanding of human congenital anomalies involving secondary neurulation processes.

The first case of Capillaria hepatica infection in a nutria (Myocastor coypus) in Korea.

This study reports the first case of Capillaria hepatica infection in a nutria in Korea. Ten nutrias, captured near the Nakdong River, were submitted to our laboratory for necropsy. White-yellowish nodules were found in the liver of 1 of the nutrias at necropsy. Histologically, the lesions were granulomatous, and infiltrations of lipid-laden macrophages, eosinophils, and several multinucleated giant cells were observed. The lesions consisted of numerous eggs and necrotic hepatocytes. The eggs were lemon-shaped and had polar plugs at the ends of both long sides. The eggs were morphologically identified as those of C. hepatica. Worldwide, C. hepatica infection in nutrias is very rare. Nutrias are a kind of livestock, as well as wildlife; therefore, an epidemiological study for parasitic infections needs to be conducted.

Recent advances in earth-abundant transition metal-catalyzed dihydrosilylation of terminal alkynes.

Over the past few years, earth-abundant transition metal-catalyzed hydrosilylation has emerged as an ideal strategy for the synthesis of organosilanes. The success in this area of research has expanded to the advancements of alkyne dihydrosilylation reactions, offering broadened synthetic applications through the selective installation of two silyl groups. In particular, catalysts based on Fe, Co, and Ni have engendered enabling platforms for mild transformations with a range of distinct regioselectivity. This mini-review summarizes recent advances in this research field, highlighting the unique features of each system from both synthetic and mechanistic perspectives.

Functional recovery after injury of motor cortex in rats: effects of rehabilitation and stem cell transplantation in a traumatic brain injury model of cortical resection.

PURPOSE: Experimental studies and clinical trials designed to help patients recover from various brain injuries, such as stroke or trauma, have been attempted. Rehabilitation has shown reliable, positive clinical outcome in patients with various brain injuries. Transplantation of exogenous neural stem cells (NSCs) to repair the injured brain is a potential tool to help patient recovery. METHODS: This study aimed to evaluate the therapeutic efficacy of a combination therapy consisting of rehabilitation and NSC transplantation compared to using only one modality. A model of motor cortex resection in rats was used to create brain injury in order to obtain consistent and prolonged functional deficits. The therapeutic results were evaluated using three methods during an 8-week period with a behavioral test, motor-evoked potential (MEP) measurement, and measurement of the degree of endogenous NSC production. RESULTS: All three treatment groups showed the effects of treatment in the behavioral test, although the NSC transplantation alone group (CN) exhibited slightly worse results than the rehabilitation alone group (CR) or the combination therapy group (CNR). The latency on MEP was shortened to a similar extent in all three groups compared to the untreated group (CO). However, the enhancement of endogenous NSC proliferation was dramatically reduced in the CN group compared not only to the CR and CNR groups but also to the CO group. The CR and CNR groups seemed to prolong the duration of endogenous NSC proliferation compared to the untreated group. CONCLUSIONS: A combination of rehabilitation and NSC transplantation appears to induce treatment outcomes that are similar to rehabilitation alone. Further studies are needed to evaluate the electrophysiological outcome of recovery and the possible effect of prolonging endogenous NSC proliferation in response to NSC transplantation and rehabilitation.

Radio Tracking Reveals the Home Range and Activity Patterns of Nutria (Myocastor coypus) in the Macdo Wetland in South Korea.

Nutria (Myocastor coypus) are semi-aquatic rodents that were introduced in South Korea for commercial farming but significantly damaged aquatic ecosystems. Understanding nutria ecological behavior is essential for developing effective control and eradication strategies to mitigate their impacts. Thus, this study aimed to investigate the home range and activity patterns of 24 nutria (12 males and 12 females) in the Macdo wetland in South Korea from 2015-2016 through radio tracking. The average minimum convex polygon home range of the nutria was 0.29 ± 0.55 km2, with a 95% kernel density estimation (KDE) home range of 0.43 ± 0.85 km2 and a 50% KDE home range of 0.05 ± 1.1 km2. The home range of males was larger than that of females; however, the winter home range of females was as large as that of males. The home range also varied seasonally, with the smallest observed in winter. The nutria showed crepuscular and nocturnal activity patterns throughout the year, with no significant difference between sexes. The activities in spring, summer, and autumn showed no significant differences, but the activity in winter was significantly different from that in the other seasons. This study may serve as a basis for developing appropriately timed and scaled management strategies to mitigate the impacts of nutria on ecosystems. In conclusion, several environmental and biological factors contribute to the behavior of nutria in South Korea.

Habitat utilization distribution of sika deer (Cervus nippon).

Habitat-specific and movement-related behavioral studies are essential for the development of sustainable biodiversity management practices. Although the number of studies on sika deer is increasing, habitat utilization distribution (UD)-related studies remain limited. In this study, we investigated the habitat UD behavior of sika deer (Cervus nippon) using a literature survey and an experimental study on Suncheon Bonghwasan Mountain, South Korea. We reviewed home range-related literature on sika deer published between 1982 and 2019 in order to assess their estimation methods, study region, and research background. We observed that the number of studies on sika deer has increased. The minimum convex polygon (MCP) has been utilized the most to estimate habitat UD, followed by the kernel density (KD), the Brownian bridge model, and a combination of these methods. The average home ranges (95 % utilization distribution) of sika deer from the literature survey were 236.99 ha and 1183.96 ha using the minimum convex polygon and kernel density approaches, respectively. The five female deer in our experimental study on Suncheon Bonghwasan Mountain had a mean home range of 66.831 ± 15.241 ha using the MCP approach and 78.324 ± 20.82 ha using the KD approach. The UD behavior of sika deer explored in this research is expected to benefit future scholars and policymakers when formulating deer management and wildlife conservation strategies.

Distribution of sika deer (Cervus nippon) and the bioclimatic impact on their habitats in South Korea.

Invasive species and climate change are primary factors influencing biodiversity, and examining the behavior of invasive species is essential for effective conservation management. Here, we report the global distribution of the sika deer (Cervus nippon) based on locations reported in published literature (Google Scholar), the Global Biodiversity Information Facility (GBIF) database, and the International Union for Conservation of Nature report. We used the maximum entropy (Maxent) model to examine the impact of climate change on sika deer habitats in South Korea based on GBIF occurrence data and WorldClim bioclimatic variables. Habitat suitability analysis was performed using the Maxent model under Representative Concentration Pathways (RCPs) 4.5 and 8.5 (for predicted climatic conditions in both 2050 and 2070) to project the effects of different climate change scenarios on South Korean sika deer habitats. We identified that the sika deer is distributed in 39 countries worldwide. Due to climate change effects, South Korean sika deer habitats will decline by approximately 24.98% and 20.63% (under RCP 4.5) and by 50.51% and 57.35% (under RCP 8.5) by 2050 and 2070, respectively. Our findings shed light on sika deer ecology and provide reference data for future conservation management strategies and policy design.

Assessing the Potential Distribution of Oxalis latifolia, a Rapidly Spreading Weed, in East Asia under Global Climate Change.

Oxalis latifolia, a perennial herbaceous weed, is a highly invasive species that poses a threat to agricultural lands worldwide. East Asia is under a high risk of invasion of O. latifolia under global climate change. To evaluate this risk, we employed maximum entropy modeling considering two shared socio-economic pathways (SSP2-4.5 and SSP5-8.5). Currently, a small portion (8.02%) of East Asia is within the O. latifolia distribution, with the highest coverages in Chinese Taipei, China, and Japan (95.09%, 9.8%, and 0.24%, respectively). However, our projections indicated that this invasive weed will likely be introduced to South Korea and North Korea between 2041 and 2060 and 2081 and 2100, respectively. The species is expected to cover approximately 9.79% and 23.68% (SSP2-4.5) and 11.60% and 27.41% (SSP5-8.5) of the total land surface in East Asia by these time points, respectively. South Korea and Japan will be particularly susceptible, with O. latifolia potentially invading up to 80.73% of their territory by 2081-2100. Mongolia is projected to remain unaffected. This study underscores the urgent need for effective management strategies and careful planning to prevent the introduction and limit the expansion of O. latifolia in East Asian countries.

Climate change induced habitat expansion of nutria (Myocastor coypus) in South Korea.

The nutria, (Myocastor coypus), is a semiaquatic rodent native to the subtropical and temperate regions of South America. The species was introduced to South Korea for meat and fur production purposes and a wild population has become established. The species subsequently invaded aquatic ecosystems and destroyed aquatic vegetation and cultivated crops. Thus, it is essential to understand their current distribution and future range expansion for effective control and eradication strategies to reduce the risk of colonization into new regions. In this study, we used niche modeling procedure to identify potentially suitable habitats for M. coypus under current and future predicted climate change using the maximum entropy algorithm. We found that the main habitat area of M. coypus is expected to expand under a warming climate from ~ 4069 km2 in the southern and southeastern regions of South Korea, to the northern border of the country, with estimated ranges of 21,744 km2, 55,859 km2, and 64,937 km2 by 2030, 2050, and 2070, respectively. The findings of the present study assist in identifying the future distribution and potential dispersion routes of M. coypus in South Korea, which is important for informing the government regarding essential management actions plans at regional and local scales.

Climate Change Influences the Spread of African Swine Fever Virus.

Climate change is an inevitable and urgent issue in the current world. African swine fever virus (ASFV) is a re-emerging viral animal disease. This study investigates the quantitative association between climate change and the potential spread of ASFV to a global extent. ASFV in wild boar outbreak locations recorded from 1 January 2019 to 29 July 2022 were sampled and investigated using the ecological distribution tool, the Maxent model, with WorldClim bioclimatic data as the predictor variables. The future impacts of climate change on ASFV distribution based on the model were scoped with Representative Concentration Pathways (RCP 2.6, 4.5, 6.0, and 8.5) scenarios of Coupled Model Intercomparison Project 5 (CMIP5) bioclimatic data for 2050 and 2070. The results show that precipitation of the driest month (Bio14) was the highest contributor, and annual mean temperature (Bio1) was obtained as the highest permutation importance variable on the spread of ASFV. Based on the analyzed scenarios, we found that the future climate is favourable for ASFV disease; only quantitative ratios are different and directly associated with climate change. The current study could be a reference material for wildlife health management, climate change issues, and World Health Organization sustainability goal 13: climate action.

Predicting Impacts of Climate Change on Northward Range Expansion of Invasive Weeds in South Korea.

Predicting the distribution of invasive weeds under climate change is important for the early identification of areas that are susceptible to invasion and for the adoption of the best preventive measures. Here, we predicted the habitat suitability of 16 invasive weeds in response to climate change and land cover changes in South Korea using a maximum entropy modeling approach. Based on the predictions of the model, climate change is likely to increase habitat suitability. Currently, the area of moderately suitable and highly suitable habitats is estimated to be 8877.46 km2, and 990.29 km2, respectively, and these areas are expected to increase up to 496.52% by 2050 and 1439.65% by 2070 under the representative concentration pathways 4.5 scenario across the country. Although habitat suitability was estimated to be highest in the southern regions (<36° latitude), the central and northern regions are also predicted to have substantial increases in suitable habitat areas. Our study revealed that climate change would exacerbate the threat of northward weed invasions by shifting the climatic barriers of invasive weeds from the southern region. Thus, it is essential to initiate control and management strategies in the southern region to prevent further invasions into new areas.

Spatial Movement Patterns and Local Co-Occurrence of Nutria Individuals in Association with Habitats Using Geo-Self-Organizing Map (Geo-SOM).

Nutrias (Myocastor coypus) were imported to South Korea for farming in 1985; individuals escaped captivity and established wild populations in natural ecosystems in the late 1990s. Numerous studies have focused on their monitoring and management; however, information on the continuous movement of individuals is not available. In this study, telemetry data from field conditions were used to identify the nearest-neighbor distances of individuals in association with environmental factors, including plant type, land cover, and biological parameters. The minimum nearest-neighbor distances for the different sexes were, overall, according to the minimum distances for the same sex. Local co-occurrences of individuals, either of the same or different sex, were seasonal. Tall grasslands, followed by herbaceous vegetation, were associated with the co-occurrence of different sexes. Conversely, floating-leaved hydrophytes, followed by xeric herbaceous vegetation, were correlated with the co-occurrence of the same sex. Local female-male co-occurrences were negatively associated with male-male co-occurrences but not with female-female co-occurrences, suggesting male dominance in group formations. Movement and co-occurrence information extracted using Geo-self-organizing maps furthers our understanding of population dispersal and helps formulate management strategies for nutria populations.

Expression of neuronal antigens and related ventral and dorsal proteins in the normal spinal cord and a surgically induced open neural tube defect of the spine in chick embryos: an immunohistochemical study.

OBJECTIVE: The aims of this study were to elucidate the processes of neuronal differentiation and ventrodorsal patterning in the spinal cord of the chick embryo from embryonic day (E) 3 to E17 and to study the effect of a prenatal spinal open neural tube defect (ONTD) on these processes. METHOD: Expression patterns of neuronal antigens (neuronal nuclear antigen, neurofilament-associated protein (NAP), and synaptophysin) and related ventral markers [sonic hedgehog, paired box gene (PAX)6, and islet-1], and dorsal markers (bone morphogenetic protein, Notch homolog 1, and PAX7) were investigated in the normal spinal cord and in a surgically induced spinal ONTD in chick embryos. Four normal and ONTD chick embryos were used for each antigen group. RESULT & CONCLUSION: There were no differences in the expression of neuronal and ventrodorsal markers between the control and ONTD groups. NAP and synaptophysin were useful for identifying dorsal structures in the distorted anatomy of the ONTD chicks.

Characteristic of complete mitochondrial genome and phylogenetic status of a muskrat, Ondatra zibethicus (Rodentia: Cricetidae) in South Korea.

The complete mitochondrial genome of Muskrat, Ondatra zibethicus (Rodentia: Cricetidae) in Korea was sequenced for the first time using the next-generation sequencing method to understand its evolutionary relationship and to be helpful to establish a management plan. This mitogenome was 16,350 base pairs in length, containing 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one control region. Its overall A, C, G, and T contents were 32.0%, 26.9%, 12.6%, and 28.5%, respectively. A + T content (63.7%) was higher than G + C content (36.3%). We made the phylogenetic tree of muskrat and other 12 species of order Rodentia distributed in Korea.

Reproducible and persistent weakness in adult rats after surgical resection of motor cortex: evaluation with limb placement test.

OBJECT: The purpose of this study was to develop a new rat model for surgical brain injury with motor weakness and to find an adequate behavior test for the application of the model. METHODS: Thirty rats were divided into three groups: craniectomy (n = 10), durotomy (n = 10), and corticectomy (n = 10) groups. The coordinates of the three points from the bregma (coordinate A = +4,+1, B = -2,+1, and C = +4,+6). We evaluated right limb motor performance by the modified limb placement test and the cylinder test. CONCLUSION: Persistent motor weakness was observed for 2 months in the corticectomy group by the limb placement test, whereas the cylinder test could not detect the weakness. We established a reproducible and persistent rat brain injury model and found that the modified limb placement test is sensitive enough to evaluate residual subtle weakness in this model.