LRRTM3 regulates activity-dependent synchronization of synapse properties in topographically connected hippocampal neural circuits.

Synaptic cell-adhesion molecules (CAMs) organize the architecture and properties of neural circuits. However, whether synaptic CAMs are involved in activity-dependent remodeling of specific neural circuits is incompletely understood. Leucine-rich repeat transmembrane protein 3 (LRRTM3) is required for the excitatory synapse development of hippocampal dentate gyrus (DG) granule neurons. Here, we report that Lrrtm3-deficient mice exhibit selective reductions in excitatory synapse density and synaptic strength in projections involving the medial entorhinal cortex (MEC) and DG granule neurons, accompanied by increased neurotransmitter release and decreased excitability of granule neurons. LRRTM3 deletion significantly reduced excitatory synaptic innervation of hippocampal mossy fibers (Mf) of DG granule neurons onto thorny excrescences in hippocampal CA3 neurons. Moreover, LRRTM3 loss in DG neurons significantly decreased mossy fiber long-term potentiation (Mf-LTP). Remarkably, silencing MEC-DG circuits protected against the decrease in the excitatory synaptic inputs onto DG and CA3 neurons, excitability of DG granule neurons, and Mf-LTP in Lrrtm3-deficient mice. These results suggest that LRRTM3 may be a critical factor in activity-dependent synchronization of the topography of MEC-DG-CA3 excitatory synaptic connections. Collectively, our data propose that LRRTM3 shapes the target-specific structural and functional properties of specific hippocampal circuits.

A general equilibrium assessment of COVID-19's labor productivity impacts on china's regional economies.

This study introduces a database for analyzing COVID-19's impacts on China's regional economies. This database contains various sectoral and regional economic outcomes at the weekly and monthly level. In the context of a general equilibrium trade model, we first formulate a mathematical representation of the Chinese regional economy and calibrate the model with China's multi-regional input-output table. We then utilize the monthly provincial and sectoral value-added and national trade series to estimate COVID-19's province-by-month labor-productivity impacts from February 2020 to September 2020. As a year-on-year comparison, relative to February 2019 levels, we find an average 39.5% decrease in labor productivity (equivalent to around 305 million jobs) and an average 25.9% decrease in welfare. Labor productivity and welfare quickly returned to the recent high-growth trends for China in the latter half of 2020. By September 2020, relative to September 2019, average labor productivity increased by 12.2% (equivalent to around 94 million jobs) and average welfare increased by 8.2%.

Overexpression of pigment epithelium-derived factor in placenta-derived mesenchymal stem cells promotes mitochondrial biogenesis in retinal cells.

Pigment epithelium-derived factor (PEDF) plays a role in protecting retinal pigment epithelial (RPE) cells from oxidative stress (OS), a causative factor of RPE cell death. Genetically modified mesenchymal stem cells (MSCs) can be used to treat critical and incurable retinal diseases. Here, we overexpressed PEDF in placenta-derived MSCs (PD-MSCsPEDF, PEDF+) using a nonviral gene delivery system and evaluated the characteristics of PD-MSCsPEDF and their potential regenerative effects on RPE cells damaged by H2O2-induced OS. PD-MSCsPEDF maintained their stemness, cell surface marker, and differentiation potential characteristics. Compared to naive cells, PD-MSCsPEDF promoted mitochondrial respiration by enhancing biogenesis regulators (e.g., NRF1, PPARGC1A, and TFAM) as well as antioxidant enzymes (e.g., HMOXs, SODs, and GPX1). Compared to OS-damaged RPE cells cocultured with naive cells, OS-damaged RPE cells cocultured with PD-MSCsPEDF showed PEDF upregulation and VEGF downregulation. The expression levels of antioxidant genes and RPE-specific genes, such as RPE65, RGR, and RRH, were significantly increased in RPE cells cocultured with PD-MSCsPEDF. Furthermore, OS-damaged RPE cells cocultured with PD-MSCsPEDF had dramatically enhanced mitochondrial functions, and antiapoptotic effects improved due to cell survival signaling pathways. In the H2O2-induced retinal degeneration rat model, compared to administration of the naive counterpart, intravitreal administration of PD-MSCsPEDF alleviated proinflammatory cytokines and restored retinal structure and function by increasing PEDF expression and decreasing VEGF expression. Intravitreal administration of PD-MSCsPEDF also protected retinal degeneration against OS by increasing antioxidant gene expression and regulating the mitochondrial ROS levels and biogenesis. Taken together, PEDF overexpression in PD-MSCs improved the mitochondrial activities and induced OS-damaged RPE cell regeneration by regulating the oxidative status and mitochondrial biogenesis in vitro and in vivo. These data suggest that genetic modification of PEDF in PD-MSCs might be a new cell therapy for the treatment of retinal degenerative diseases.

RAPGEF2 mediates oligomeric Aß-induced synaptic loss and cognitive dysfunction in the 3xTg-AD mouse model of Alzheimer's disease.

AIMS: Amyloid-ß (Aß) oligomers trigger synaptic degeneration that precedes plaque and tangle pathology. However, the signalling molecules that link Aß oligomers to synaptic pathology remain unclear. Here, we addressed the potential role of RAPGEF2 as a novel signalling molecule in Aß oligomer-induced synaptic and cognitive impairments in human-mutant amyloid precursor protein (APP) mouse models of Alzheimer's disease (AD). METHODS: To investigate the role of RAPGEF2 in Aß oligomer-induced synaptic and cognitive impairments, we utilised a combination of approaches including biochemistry, molecular cell biology, light and electron microscopy, behavioural tests with primary neuron cultures, multiple AD mouse models and post-mortem human AD brain tissue. RESULTS: We found significantly elevated RAPGEF2 levels in the post-mortem human AD hippocampus. RAPGEF2 levels also increased in the transgenic AD mouse models, generating high levels of Aß oligomers before exhibiting synaptic and cognitive impairment. RAPGEF2 upregulation activated the downstream effectors Rap2 and JNK. In cultured hippocampal neurons, oligomeric Aß treatment increased the fluorescence intensity of RAPGEF2 and reduced the number of dendritic spines and the intensities of synaptic marker proteins, while silencing RAPGEF2 expression blocked Aß oligomer-induced synapse loss. Additionally, the in vivo knockdown of RAPGEF2 expression in the AD hippocampus prevented cognitive deficits and the loss of excitatory synapses. CONCLUSIONS: These findings demonstrate that the upregulation of RAPGEF2 levels mediates Aß oligomer-induced synaptic and cognitive disturbances in the AD hippocampus. We propose that an early intervention regarding RAPGEF2 expression may have beneficial effects on early synaptic pathology and memory loss in AD.

Haploinsufficiency of Cyfip2 Causes Lithium-Responsive Prefrontal Dysfunction.

OBJECTIVE: Genetic variants of the cytoplasmic FMR1-interacting protein 2 (CYFIP2) encoding an actin-regulatory protein are associated with brain disorders, including intellectual disability and epilepsy. However, specific in vivo neuronal defects and potential treatments for CYFIP2-associated brain disorders remain largely unknown. Here, we characterized Cyfip2 heterozygous (Cyfip2+/- ) mice to understand their neurobehavioral phenotypes and the underlying pathological mechanisms. Furthermore, we examined a potential treatment for such phenotypes of the Cyfip2+/- mice and specified a neuronal function mediating its efficacy. METHODS: We performed behavioral analyses of Cyfip2+/- mice. We combined molecular, ultrastructural, and in vitro and in vivo electrophysiological analyses of Cyfip2+/- prefrontal neurons. We also selectively reduced CYFIP2 in the prefrontal cortex (PFC) of mice with virus injections. RESULTS: Adult Cyfip2+/- mice exhibited lithium-responsive abnormal behaviors. We found increased filamentous actin, enlarged dendritic spines, and enhanced excitatory synaptic transmission and excitability in the adult Cyfip2+/- PFC that was restricted to layer 5 (L5) neurons. Consistently, adult Cyfip2+/- mice showed increased seizure susceptibility and auditory steady-state responses from the cortical electroencephalographic recordings. Among the identified prefrontal defects, lithium selectively normalized the hyperexcitability of Cyfip2+/- L5 neurons. RNA sequencing revealed reduced expression of potassium channel genes in the adult Cyfip2+/- PFC. Virus-mediated reduction of CYFIP2 in the PFC was sufficient to induce L5 hyperexcitability and lithium-responsive abnormal behavior. INTERPRETATION: These results suggest that L5-specific prefrontal dysfunction, especially hyperexcitability, underlies both the pathophysiology and the lithium-mediated amelioration of neurobehavioral phenotypes in adult Cyfip2+/- mice, which can be implicated in CYFIP2-associated brain disorders. ANN NEUROL 2020;88:526-543.

Functional and morphological evaluation of blue light-emitting diode-induced retinal degeneration in mice.

PURPOSE: The purpose of this study was to evaluate a retinal degeneration (RD) model induced by exposing mice to a blue light-emitting diode (LED), which led to photoreceptor cell death. METHODS: RD was induced in BALB/c mice by exposure to a blue LED (460 nm) for 2 hours. Retinal function was examined using scotopic electroretinography (ERG). Histopathological changes were assessed by hematoxylin and eosin (H&E) staining and electron microscopy. Apoptotic cell death was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. In addition, retinal inflammation and oxidative stress were evaluated by immunohistochemistry with anti-glial fibrillary acidic protein (GFAP) and anti-8-hydroxy-2'-deoxyguanosine (8-OHdG), respectively. RESULTS: Scotopic ERG showed that blue LED exposure resulted in a decrease in both a-waves and b-waves in mice retinas in an illuminance-dependent manner. H&E, TUNEL assay, and electron microscopy revealed massive photoreceptor cell death by apoptosis in the central region of the retina. Retinal stress and inflammation were detected by increased expression of GFAP and by electron microscopy findings demonstrating microglia infiltration in the outer nuclear layer and subretinal space. In addition, increased labeling of 8-OHdG was observed in the retinas from blue LED exposure. CONCLUSIONS: These results suggest that blue LED-induced RD may be a useful animal model in which to study the pathogenesis of RD, including age-related macular degeneration, and to evaluate the effects of new therapeutic agents prior to clinical trials, where oxidative stress and inflammation are the underlying RD mechanisms.

Protective effects of poly(lactic-co-glycolic acid) nanoparticles loaded with erythropoietin stabilized by sodium cholate against glutamate-induced neurotoxicity.

The final aim of this study was to confirm the neuroprotective effects of recombinant human erythropoietin (rhEPO)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles stabilized by sodium cholate (rhEPO-Ch-NP) and compare their effects with those of rhEPO using an in vitro model of cerebral ischemia. Glutamate-induced excitotoxic damage on SH-SY5Y cells, a human neuroblastoma cell line, with or without rhEPO-Ch-NPs was quantitatively evaluated. The rhEPO-Ch-NPs were carefully prepared using a water-in-oil-in-water (w/o/w) emulsion solvent evaporation technique with PLGA, sodium cholate hydrate, and ethyl acetate. The rhEPO-Ch-NPs were fully characterized by both transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). In addition, significant intracellular uptake of these particles was monitored by confocal microscopy. Notably, the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and nuclear changes observed by 4',6-diamidino-2-phenylindole (DAPI) staining in SH-SY5Y cells demonstrated that rhEPO-Ch-NPs were safer at any concentration investigated and rescued more neuronal cells, while preserving normocytic features against glutamate-induced excitotoxic damages compared to rhEPO.

Neuroprotective effect of estradiol-loaded poly(lactic-co-glycolic acid) nanoparticles on glutamate-induced excitotoxic neuronal death.

Different concentrations of estradiol (E2)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (E2-PLGA-NPs) were synthesized using the emulsion-diffusion method. Transmission electron microscopy results showed that the average particle size of E2-PLGA-NPs was 98 ± 1.9 nm when stabilized with polyvinyl alcohol and 103 ± 4.9 nm when stabilized with Tween-80. Fourier transform-infrared spectroscopy with diamond attenuated total reflectance was used to identify the presence or absence of E2 molecules in PLGA nanocapsules. Cell proliferation was assessed after treating SH-SY5Y neuroblastoma cells with 1 nM-1 µM of E2 and E2-PLGA-NPs. The neuroprotective efficacy against glutamate-induced excitotoxicity was also investigated in SH-SY5Y neuroblastoma cells. Neuroprotection was greater in E2-PLGA-NP-treated cells than in cells treated with the same concentration of E2. Furthermore, E2- and E2-PLGA-NP-treated cells expressed more p-ERK1/2 and p-CREB than cells treated with glutamate only. Moreover, the expression of p-ERK1/2 was higher than that of p-CREB. In this study, p-ERK1/2 had a greater influence on the neuroprotective effect of E2 and E2-PLGA-NPs than p-CREB.

Selective Regional Loss of Cortical Synapses Lacking Presynaptic Mitochondria in the 5xFAD Mouse Model.

Synaptic loss in Alzheimer's disease (AD) is strongly correlated with cognitive impairment. Accumulating evidence indicates that amyloid pathology leads to synaptic degeneration and mitochondrial damage in AD. However, it remains unclear whether synapses and presynaptic mitochondria are differentially affected in various cortical regions of the AD brain at the ultrastructural level. Using serial block-face scanning electron microscopy, we assessed synaptic structures in the medial prefrontal cortex (mPFC) and primary visual cortex (V1) of the 5xFAD mouse model of AD. At 6 months of age, 5xFAD mice exhibited significantly elevated levels of amyloid deposition in layer 2/3 of the mPFC but not V1. Accordingly, three-dimensional reconstruction of synaptic connectivity revealed a significant reduction in excitatory synaptic density in layer 2 of the mPFC, but not V1, of male transgenic mice. Notably, the density of synapses lacking presynaptic mitochondria was selectively decreased in the mPFC of 5xFAD mice, with no change in the density of mitochondria-containing synapses. Further classification of spines into shape categories confirmed a preferential loss of thin spines whose presynaptic boutons were largely devoid of mitochondria in the 5xFAD mPFC. Furthermore, the number of mitochondria per bouton in spared mitochondria-containing boutons was reduced in the mPFC, but not V1, of 5xFAD mice. Collectively, these results highlight region-specific vulnerability of cortical synapses to amyloid deposition and suggest that the presence of presynaptic mitochondria may affect synaptic degeneration in AD.

Altered presynaptic function and number of mitochondria in the medial prefrontal cortex of adult Cyfip2 heterozygous mice.

Variants of the cytoplasmic FMR1-interacting protein (CYFIP) gene family, CYFIP1 and CYFIP2, are associated with numerous neurodevelopmental and neuropsychiatric disorders. According to several studies, CYFIP1 regulates the development and function of both pre- and post-synapses in neurons. Furthermore, various studies have evaluated CYFIP2 functions in the postsynaptic compartment, such as regulating dendritic spine morphology; however, no study has evaluated whether and how CYFIP2 affects presynaptic functions. To address this issue, in this study, we have focused on the presynapses of layer 5 neurons of the medial prefrontal cortex (mPFC) in adult Cyfip2 heterozygous (Cyfip2+/-) mice. Electrophysiological analyses revealed an enhancement in the presynaptic short-term plasticity induced by high-frequency stimuli in Cyfip2+/- neurons compared with wild-type neurons. Since presynaptic mitochondria play an important role in buffering presynaptic Ca2+, which is directly associated with the short-term plasticity, we analyzed presynaptic mitochondria using electron microscopic images of the mPFC. Compared with wild-type mice, the number, but not the volume or cristae density, of mitochondria in both presynaptic boutons and axonal processes in the mPFC layer 5 of Cyfip2+/- mice was reduced. Consistent with an identification of mitochondrial proteins in a previously established CYFIP2 interactome, CYFIP2 was detected in a biochemically enriched mitochondrial fraction of the mouse mPFC. Collectively, these results suggest roles for CYFIP2 in regulating presynaptic functions, which may involve presynaptic mitochondrial changes.

Elevated protein synthesis in microglia causes autism-like synaptic and behavioral aberrations.

Mutations that inactivate negative translation regulators cause autism spectrum disorders (ASD), which predominantly affect males and exhibit social interaction and communication deficits and repetitive behaviors. However, the cells that cause ASD through elevated protein synthesis resulting from these mutations remain unknown. Here we employ conditional overexpression of translation initiation factor eIF4E to increase protein synthesis in specific brain cells. We show that exaggerated translation in microglia, but not neurons or astrocytes, leads to autism-like behaviors in male mice. Although microglial eIF4E overexpression elevates translation in both sexes, it only increases microglial density and size in males, accompanied by microglial shift from homeostatic to a functional state with enhanced phagocytic capacity but reduced motility and synapse engulfment. Consequently, cortical neurons in the mice have higher synapse density, neuroligins, and excitation-to-inhibition ratio compared to control mice. We propose that functional perturbation of male microglia is an important cause for sex-biased ASD.

Amelioration of Mouse Retinal Degeneration After Blue LED Exposure by Glycyrrhizic Acid-Mediated Inhibition of Inflammation.

Glycyrrhizic acid (GA) is a major component in the root and rhizomes of licorice (Glycyrrhiza glabra), which have been used as an herbal medicine, because of its anti-inflammatory activity. GA is known as an inhibitor of high-mobility group box 1 (HMGB1), which is involved in the pathogenesis of various inflammatory diseases including inner retinal neuropathy. In this study, we examined the effect of GA in a mouse model of retinal degeneration (RD), the leading cause of blindness. RD was induced by exposure to a blue light-emitting diode (LED). In functional assessment, electroretinography showed that the amplitudes of both a- and b-waves were reduced in RD mice, whereas they were significantly increased in GA-treated RD mice (P < 0.05), compared to those in non-treated RD animals. In histological assessment, GA treatment preserved the outer nuclear layer where photoreceptors reside and reduced photoreceptor cell death. GA-treated retinas showed significantly reduced expression of proinflammatory cytokines such as TNF-α, IL-6, IL-1ß, CCL2 and 6, iNOS, and COX-2 (P < 0.05), compared to that in non-treated retinas. Immunohistochemistry showed that Iba-1 and GFAP expression was markedly reduced in GA-treated retinas, indicating decreased glial response and inflammation. Interestingly, HMGB1 expression was reduced in non-treated RD retinas whereas GA paradoxically increased its expression. These results demonstrate that GA preserves retinal structure and function by inhibiting inflammation in blue LED-induced RD, suggesting a potential application of GA as a medication for RD. In addition, we propose a potential retinal protective function of HMGB1 in the pathogenesis of RD.

Gait Ignition Failure in JNPL3 Human Tau-mutant Mice.

Cognitive impairments and motor dysfunction are commonly observed behavioral phenotypes in genetic animal models of neurodegenerative diseases. JNPL3 transgenic mice expressing human P301L-mutant tau display motor disturbances with age- and gene dose-dependent development of neurofibrillary tangles, suggesting that tau pathology causes neurodegeneration associated with motor behavioral abnormalities. Although gait ignition failure (GIF), a syndrome marked by difficulty in initiating locomotion, has been described in patients with certain forms of tauopathies, transgenic mouse models mirroring human GIF syndrome have yet to be reported. Using the open field and balance beam tests, here we discovered that JNPL3 homozygous mice exhibit a marked delay of movement initiation. The elevated plus maze excluded the possibility that hesitation to start in JNPL3 mice was caused by enhanced levels of anxiety. Considering the normal gait ignition in rTg4510 mice expressing the same mutant tau in the forebrain, GIF in JNPL3 mice seems to arise from abnormal tau deposition in the hindbrain areas involved in locomotor initiation. Accordingly, immunohistochemistry revealed highly phosphorylated paired helical filament tau in JNPL3 brainstem areas associated with gait initiation. Together, these findings demonstrate a novel behavioral phenotype of impaired gait initiation in JNPL3 mice and underscore the value of this mouse line as a tool to study the neural mechanisms and potential treatments for human GIF syndrome.

Increased Expression of Osteopontin in Retinal Degeneration Induced by Blue Light-Emitting Diode Exposure in Mice.

Osteopontin (OPN) is a multifunctional adhesive glycoprotein that is implicated in a variety of pro-inflammatory as well as neuroprotective and repair-promoting effects in the brain. As a first step towards understanding the role of OPN in retinal degeneration (RD), we examined changes in OPN expression in a mouse model of RD induced by exposure to a blue light-emitting diode (LED). RD was induced in BALB/c mice by exposure to a blue LED (460 nm) for 2 h. Apoptotic cell death was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. In order to investigate changes in OPN in RD, western blotting and immunohistochemistry were performed. Anti-OPN labeling was compared to that of anti-glial fibrillary acidic protein (GFAP), which is a commonly used marker for retinal injury or stress including inflammation. OPN expression in RD retinas markedly increased at 24 h after exposure, was sustained through 72 h, and subsided at 120 h. Increased OPN expression was observed co-localized with microglial cells in the outer nuclear layer (ONL), outer plexiform layer (OPL), and subretinal space. Expression was restricted to the central retina in which photoreceptor cell death occurred. Interestingly, OPN expression in the ONL/OPL was closely associated with microglia, whereas most of the OPN plaques observed in the subretinal space were not. Immunogold electron microscopy demonstrated that OPN was distributed throughout the cytoplasm of microglia and in nearby fragments of degenerating photoreceptors. In addition, we found that OPN was induced more acutely and with greater region specificity than GFAP. These results indicate that OPN may be a more useful marker for retinal injury or stress, and furthermore act as a microglial pro-inflammatory mediator and a phagocytosis-inducing opsonin in the subretinal space. Taken together, our data suggest that OPN plays an important role in the pathogenesis of RD.

Neuroprotective effect of NecroX-5 against retinal degeneration in rodents.

NecroX-5 is a derivative of cyclopentylamino carboxymethylthiazolylindole (NecroX), an inhibitor of necrosis/necroptosis. NecroX-5 has been shown to scavenge mitochondrial reactive oxygen and nitrogen species, and thus preventing necrotic cell death against various kinds of oxidative stress in several tissues, including the brain. To examine the effect of NecroX-5 on retinal degeneration (RD), RD was induced in Sprague-Dawley rats by an intraperitoneal injection of N-methyl-N-nitrosourea and in BALB/c mice by blue light-emitting diode exposure. Scotopic electroretinography recording was used to evaluate retinal function. For histological evaluation, hematoxylin and eosin staining, terminal deoxynucleotidyl transferase dUTP nick end labeling, and immunohistochemistry were performed. Electroretinography recordings showed that a-waves and b-waves were significantly reduced in both RD rats and mice, whereas the amplitudes of both waves were significantly increased in both NecroX-5-treated RD rats and mice compared with untreated RD animals. In hematoxylin and eosin staining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay, the outer nuclear layer where photoreceptors reside appeared to be more preserved, and there were fewer apoptotic cells in NecroX-5-treated RD retinas than in untreated RD retinas. In addition, immunohistochemistry with antiglial fibrillary acidic protein and anti-8-hydroxy-2'-deoxyguanosine showed lower levels of retinal injury and oxidative stress in NecroX-5-treated RD retinas than in untreated RD retinas. These results indicated that NecroX-5 protects retinal neurons from experimentally induced RD, suggesting that NecroX-5 may have a potential for the treatment of RD as a medication.

Tentonin 3/TMEM150c Confers Distinct Mechanosensitive Currents in Dorsal-Root Ganglion Neurons with Proprioceptive Function.

Touch sensation or proprioception requires the transduction of mechanical stimuli into electrical signals by mechanoreceptors in the periphery. These mechanoreceptors are equipped with various transducer channels. Although Piezo1 and 2 are mechanically activated (MA) channels with rapid inactivation, MA molecules with other inactivation kinetics have not been identified. Here we report that heterologously expressed Tentonin3 (TTN3)/TMEM150C is activated by mechanical stimuli with distinctly slow inactivation kinetics. Genetic ablation of Ttn3/Tmem150c markedly reduced slowly adapting neurons in dorsal-root ganglion neurons. The MA TTN3 currents were inhibited by known blockers of mechanosensitive ion channels. Moreover, TTN3 was localized in muscle spindle afferents. Ttn3-deficient mice exhibited the loss of coordinated movements and abnormal gait. Thus, TTN3 appears to be a component of a mechanosensitive channel with a slow inactivation rate and contributes to motor coordination. Identification of this gene advances our understanding of the various types of mechanosensations, including proprioception.

Screening of Biodegradable Function of Indigenous Ligno-degrading Mushroom Using Dyes.

The process of biodegradation in lingo-cellulosic materials is critically relevant to biospheric carbon. The study of this natural process has largely involved laboratory investigations, focused primarily on the biodegradation and recycling of agricultural by-products, generally using basidiomycetes species. In order to collect super white rot fungi and evaluate its ability to degrade lingo-cellulosic material, 35 fungal strains, collected from forests, humus soil, livestock manure, and dead trees, were screened for enzyme activities and their potential to decolorize the commercially used Poly-R 478 dye. In the laccase enzymatic analysis chemical test, 33 white rot fungi and 2 brown rot fungi were identified. The degradation ability of polycyclic aromatic hydrocarbons (PAHs) according to the utilized environmental conditions was higher in the mushrooms grown in dead trees and fallen leaves than in the mushrooms grown in humus soil and livestock manure. Using Poly-R 478 dye to assess the PAH-degradation activity of the identified strains, four strains, including Agrocybe pediades, were selected. The activities of laccase, MnP, and Lip of the four strains with PAH-degrading ability were highest in Pleurotus incarnates. 87 fungal strains, collected from forests, humus soil, livestock manure, and dead trees, were screened for enzyme activities and their potential to decolorize the commercially used Poly-R 478 dye on solid media. Using Poly-R 478 dye to assess the PAHdegrading activity of the identified strains, it was determined that MKACC 51632 and 52492 strains evidenced superior activity in static and shaken liquid cultures. Subsequent screening on plates containing the polymeric dye poly R-478, the decolorization of which is correlated with lignin degradation, resulted in the selection of a strain of Coriolus versicolor, MKACC52492, for further study, primarily due to its rapid growth rate and profound ability to decolorize poly R-478 on solid media. Considering our findings using Poly-R 478 dye to evaluate the PAH-degrading activity of the identified strains, Coriolus versicolor, MKACC 52492 was selected as a favorable strain. Coriolus versicolor, which was collected from Mt. Yeogi in Suwon, was studied for the production of the lignin-modifying enzymes laccase, manganese-dependent peroxidase (MnP), and lignin peroxidase (LiP).

Comparative analysis of sequences expressed during the liquid-cultured mycelia and fruit body stages of Pleurotus ostreatus.

To characterize genes involved in fruit body development, two complementary DNA (cDNA) libraries were constructed from RNA isolated from liquid-cultured mycelia and fruit bodies of Pleurotus ostreatus. Using single-pass sequencing of cDNA clones, 952 and 1069 expressed sequence tags (ESTs) were generated from liquid-cultured mycelia and fruit body cDNA library, respectively. A BLASTX search revealed that 390 of the liquid-cultured mycelia ESTs (41%) and 531 of the fruit body ESTs (50%) showed significant similarity to protein sequences described in the nonredudant database (E values < or =1 x 10(-5)). When liquid-cultured mycelia and fruit body ESTs were compared by the SeqMan II program, among the total of 2021 ESTs, 1256 ESTs were unigenes, and 66 unigenes (5.3%) were commonly expressed during both stages. The functional catalogs of the ESTs were made by comparison with functionally identified Saccharomyces cerevisiae genes. Liquid-cultured mycelium ESTs were compared with fruit body ESTs and changes of the expressed genes during fruit body development were analyzed.