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Abstract Background The broad continuum between tropical and temperate floras in Eastern Asia (EAS) are thought to be one of the main factors responsible for a prominent species diversity anomaly of temperate plants between EAS and eastern North America (ENS). However, how the broad continuum and niche evolution between tropical and temperate floras in EAS contributes to lineage divergence and species diversity remains largely unknown. Results Population genetic structure, demography, and determinants of genetic structure [i.e., isolation-by-distance (IBD), isolation-by-resistance (IBR), and isolation-by-environment (IBE)] of Machilus thunbergii Sieb. et Zucc. (Lauraceae) were evaluated by examining sequence variation of ten low-copy nuclear genes across 43 populations in southeast China. Climatic niche difference and potential distributions across four periods (Current, mid-Holocene, the last glacial maximum, the last interglacial) of two genetic clusters were determined by niche modelling. North and south clusters of populations in M. thunbergii were revealed and their demarcation line corresponds well with the northern boundary of tropical zone in China of Zhu & Wan. The divergence time between the clusters and demographic expansion of M. thunbergii occurred after the mid-Pleistocene climate transition (MPT, 0.8–1.2 Ma). Migration rates between clusters were asymmetrical, being much greater from north to south than the reverse. Significant effects of IBE, but non-significant effects of IBD and IBR on population genetic divergence were detected. The two clusters have different ecological niches and require different temperature regimes. Conclusions The north-south genetic differentiation may be common across the temperate-tropical boundary in southeast China. Divergent selection under different temperature regimes (possibly above and below freezing temperature in winter) could account for this divergence pattern. The broad continuum between tropical and temperate floras in EAS may have provided ample opportunities for tropical plant lineages to acquire freezing tolerance and to colonize the temperate regions during the late-Cenozoic global cooling. Our findings shed deeper insights into the high temperate plant species diversity in EAS.

Background: The broad continuum between tropical and temperate floras in Eastern Asia (EAS) are thought to be one of the main factors responsible for a prominent species diversity anomaly of temperate plants between EAS and eastern North America (ENS). However, how the broad continuum and niche evolution between tropical and temperate floras in EAS contributes to lineage divergence and species diversity remains largely unknown. Results: Population genetic structure, demography, and determinants of genetic structure [i.e., isolation-by-distance (IBD), isolation-by-resistance (IBR), and isolation-by-environment (IBE)] of Machilus thunbergii Sieb. et Zucc. (Lauraceae) were evaluated by examining sequence variation of ten low-copy nuclear genes across 43 populations in southeast China. Climatic niche difference and potential distributions across four periods (Current, mid-Holocene, the last glacial maximum, the last interglacial) of two genetic clusters were determined by niche modelling. North and south clusters of populations in M. thunbergii were revealed and their demarcation line corresponds well with the northern boundary of tropical zone in China of Zhu & Wan. The divergence time between the clusters and demographic expansion of M. thunbergii occurred after the mid-Pleistocene climate transition (MPT, 0.8–1.2 Ma). Migration rates between clusters were asymmetrical, being much greater from north to south than the reverse. Significant effects of IBE, but non-significant effects of IBD and IBR on population genetic divergence were detected. The two clusters have different ecological niches and require different temperature regimes. Conclusions: The north-south genetic differentiation may be common across the temperate-tropical boundary in southeast China. Divergent selection under different temperature regimes (possibly above and below freezing temperature in winter) could account for this divergence pattern. The broad continuum between tropical and temperate floras in EAS may have provided ample opportunities for tropical plant lineages to acquire freezing tolerance and to colonize the temperate regions during the late-Cenozoic global cooling. Our findings shed deeper insights into the high temperate plant species diversity in EAS. [ABSTRACT FROM AUTHOR]

Aim: The effect of eustasy driven by climatic oscillations on species diversification across the East China Sea (ECS) remains unclear. In this study, Machilus thunbergii (红楠, red nanmu in Chinese) was used as a model species to determine whether the ECS acted as either a "species pump" or "species vacuum" during the Pleistocene. Locations: Eastern China, and southern and central Japan. Taxon: Lauraceae. Methods: Ecological niche modelling was employed to predict the potential distribution of M. thunbergii during the Last Glacial Maximum (LGM) and the last interglacial period. Nuclear microsatellite and chloroplast markers were used to reveal the phylogeographic pattern and infer the population history of 33 M. thunbergii populations. Results: The ecological niche models suggested that the ECS provided potentially suitable habitats for M. thunbergii during the LGM. A sharp change in cpDNA haplotypes was found along the eastern China coasts, while microsatellites revealed a clinal pattern for genetic composition from eastern China to central Japan. The divergent lineages formed an admixture on the Zhoushan Archipelago of China and Kyushu Island of Japan. The estimated divergent and admixture times were c. 68 kyr and c. 15 kyr, corresponding to the periods where there were rising sea levels after the MIS4 glaciation and falling sea levels during the LGM, respectively. Main conclusions: Machilus thunbergii probably underwent alternating population isolation during interglacial periods and connection during glacial maxima across the ECS, but such periodicity of isolation and connection seems not to have promoted diversification as suggested by the species pump hypothesis. Incipient divergence has been periodically wiped out due to frequent coalescence, rendering the ECS more like a "species vacuum", particularly for species with relatively long generation lengths. [ABSTRACT FROM AUTHOR]

Thymic stromal lymphopoietin (TSLP) plays an important role in the pathophysiology of various allergic diseases that are mediated by T helper cell type-2 (Th2) responses, including asthma and atopic dermatitis. The primary focus of this study was the identification of potent inhibitors of the TSLP signaling pathway for potential therapeutic use. The 80% methanol extract of Machilus thunbergii bark significantly inhibited the signal transducer and activator of transcription 5 (STAT5) phosphorylation in human mast cell (HMC)-1 cells. Through activity-guided isolation, three lignans (1–3) were obtained and identified as (+)-galbelgin (1), meso-dihydroguaiaretic acid (2), and machilin A (3). Among them, two lignans (1 and 2) significantly inhibited STAT5 phosphorylation and TSLP/TSLPR interaction, as determined by ELISA. Our results indicated that lignans isolated from M. thunbergii are a promising resource for the treatment of allergic diseases.

During a survey of diseased plants on Wando Island, Korea from May to June 2020, a severe leaf spot disease was observed in the upper leaves of Japanese bay tree (Machilus thunbergii). Early symptoms were light blackish spots on the leaf surface and enlargement of older spots. Dry leaf spots surrounded with deep black margins were common throughout the plants. Symptomatic leaf samples were collected, and the causal pathogen was isolated on potato dextrose agar (PDA). Three fungal isolates (CMML20-1, CMML20-3, and CMML20-4) were cultured on PDA for morphological characterization at 25 °C in the darkness. Fungal colonies were circular, fast-growing, olivaceous to dark grey, and with abundant aerial mycelium. Sporulation was induced in 14 h-10 h light-dark conditions, and the conidia were single-celled, thin-walled with a smooth surface, ellipsoid with round apices, and measuring 17.5–20.5 (avg. 17.5) μm × 7.5–10.0 (7.9) μm. The morphological characteristics resembled those typical for Neofusicoccum parvum. Molecular identification was confirmed by partially sequencing the internal transcribed spacer (ITS) region and the translation elongation factor 1-α (EF1-α) genes. Pathogenicity tests were conducted on detached leaves and whole plants of M. thunbergii. High disease prevalence was observed, and Koch postulates were fulfilled. This is the first worldwide report of N. parvum causing leaf spots on Machilus thunbergii.

Heterodichogamy is defined as the presence of two flower morphs that exhibit the male and female functions at different times among individuals within a population. Heterodichogamy is regarded as an adaptation to promote outcrossing through enhanced inter-morph mating, together with a 1:1 morph ratio. However, in highly fragmented populations, the morph ratio may be more likely to be biased by stochastic events. In such a situation, individuals of a minority morph within a population are expected to have higher reproductive success than those of a majority morph, which may suffer from pollen shortages of the minority morph. In this paper, we evaluated mating patterns and male reproductive success in a highly fragmented population of Machilus thunbergii, a putative heterodichogamous evergreen laurel tree. Results of paternity analysis indicated that the selfing rate was not clearly different between the two morphs. In contrast, the proportion of intra-morph mating was higher in the majority-morph (MM) mother trees than in the minority-morph (MF) mother trees. Bayesian estimated male reproductive success indicated that male reproductive success was higher in minority-morph (MF) than in majority-morph (MM) mother trees. These findings indicate that (1) the majority morph mothers, suffering a shortage of the opposite morph pollen, could partly compensate for the reduced reproductive success by intra-morph mating rather than by selfing, and (2) negative-frequency dependent selection may be involved in the maintenance of the two morphs. [ABSTRACT FROM AUTHOR]

The projections of species distribution models (SDMs) have provided critical knowledge for conservation planning under climate change in the Republic of Korea. However, uncertainty about the SDM projections has been criticized as a major challenge to reliable projections. The present research investigated uncertainty among competing models (Model uncertainty) and uncertainty of future climate conditions (climate uncertainty) driving from different GCMs and CO 2 emission scenarios in predicting the future distributions of plants. For this purpose, using nine single-model algorithms and the pre-evaluation weighted ensemble method, we modeled the geographical distributions of Silver Magnolia ( Machilus thunbergii Siebold & Zucc.), a warm-adapted evergreen broadleaved tree; furthermore, we predicted its future distributions under 20 climate change scenarios (5 global circulation models (GCMs) × 4 CO 2 emission scenarios (RCPs)). The results showed a great variation in the accuracies of nine single-model projections: the mean AUC values of nine single-models ranged from 0.764 (SER) to 0.970 (RF), and the mean TSS ranged from 0.529 (SRE) to 0.852 (RF). RF (mean AUC = 0.970, mean TSS = 0.852) and the ensemble forecast (AUC = 0.968, TSS = 0.804) showed the highest predictive power, while SRE showed the lowest. The future distributions of Silver Magnolia projected with the ensemble SDM clearly varied according to GCMs and RCPs. The twenty climate scenarios produced twenty different projections of the magnolia prospective distribution. GCMs commonly projected the maximum range expansion under RCP 8.5 in 2050 and 2070, but CO 2 emission scenarios explaining the minimum expansions differed according to GCMs. In conclusion, our results show that GCMs, CO 2 emission scenarios and SDM algorithms produce considerable variations in the SDM projections. Therefore, this research suggests that understanding of model and climate uncertainties is critical for an effective conservation planning in forest management under climate change on the Korean Peninsula. [ABSTRACT FROM AUTHOR]

Machilus thunbergii Sieb. & Zucc. (Lauraceae) is a medicinal plant used to treat edema and pain in China and Taiwan. The anti-inflammatory effects of M. thunbergii were not clear. In this study, we evaluated the anti-inflammatory effects of M. thunbergii extract in LPS-stimulated RAW 264.7 cells. he cells were pretreated with various doses (12.5 µg/mol-100 µg/mL) of M. thunbergii extract and activated with LPS. We found that 25 µg/mL M. thunbergii extract inhibited nitric oxide (NO), prostaglandin E2 (PGE2 ), inducible nitric oxide synthetase (iNOS), and cyclooxygenase-2 (COX-2) expression, as well as levels of proinflammatory cytokines including interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α). Furthermore, M. thunbergii extract also suppressed translocation of nuclear transcription factor kappa-B (NF-κB) subunit p65 proteins into the nucleus and induced a dose-dependent inhibition of the phosphorylation of p38 mitogen-activated protein kinase (MAPK). M. thunbergii extract also increased HO-1 and Nrf2 production in a concentration-dependent manner. Taken together, these results suggest that M. thunbergii extract has an anti-inflammatory effect because it reduces levels of proinflammatory cytokines and mediators via the suppression of NF-κB and p38 MAPK activation in RAW 264.7 cells. [ABSTRACT FROM AUTHOR]

Background The bark of Machilus thunbergii (Lauraceae) has been used as a folk medicine to treat abdominal pain and distension, and leg edema in Korea. Machilin A (MA), a lignan isolated from Machilus thunbergii , exhibits several biological activities including anti-oxidant and stimulatory effects on cell differentiation and proliferation. Purpose Potential drug-interactions with MA via inhibition of cytochrome P450 (CYP) activity in human liver microsomes (HLMs), have not been investigated. Study design The inhibitory effects of MA on the activities of CYPs were investigated using cocktail probe substrates in pooled HLMs and on human recombinant cDNA-expressed CYP isoforms. Methods The nine CYP-specific substrates were incubated in HLM or recombinant cDNA-expressed CYP 1A1, 1A2 and 2B6 with MA. After incubation, the samples were injected onto a C18 column for liquid chromatography–tandem mass spectrometry analysis. To investigate the binding poses between MA and CYP, we carried out structure-based docking simulations by using software and scripts written in-house (ALIS-DOCK; A utomatic p L atform for I terative S tructure-based DOCK ing). Results MA strongly inhibited CYP1A2-mediated phenacetin O -deethylation and CYP2B6-mediated bupropion hydroxylation with IC 50 values of 3.0 and 3.9 µM, respectively, while it did not significantly inhibit other CYPs. A Dixon plot indicated that MA competitively inhibits CYP1A2 and CYP2B6 with Ki values of 0.71 and 4.1 µM, respectively. Conclusion Overall, this was the first investigation of the inhibitory effects of MA on CYP1A2 and CYP2B6 in HLMs, and it has identified that MA acts via competitive inhibition. [ABSTRACT FROM AUTHOR]

Photosynthetic characteristics of two broadleaved evergreen trees, Quercus myrsinaefolia and Machilus thunbergii , were compared in autumn and winter. The irradiance was similar in both seasons, but the air temperature was lower in winter. Under the winter conditions, net photosynthesis under natural sunlight ( A net ) in both species dropped to 4 μmol CO 2 m −2 s −1 , and the quantum yield of photosystem II (PSII) photochemistry in dark-adapted leaves ( F v / F m ) also dropped to 0.60. In both species the maximum carboxylation rates of Rubisco ( V cmax ) decreased, and the amount of Rubisco increased in winter. A decline in chlorophyll (Chl) concentration and an increase in the Chl a / b ratio in winter resulted in a reduction in the size of the light-harvesting antennae. From measurements of Chl a fluorescence parameters, both the relative fraction and the energy flux rates of thermal dissipation through other non-photochemical processes were markedly elevated in winter. The results indicate that the photosynthetic apparatus in broadleaved evergreen species in warm temperate regions responds to winter through regulatory mechanisms involving the downregulation of light-harvesting and photosynthesis coupled with increased photoprotective thermal energy dissipation to minimize photodamage in winter. These mechanisms aid a quick restart of photosynthesis without the development of new leaves in the following spring. [ABSTRACT FROM AUTHOR]

We investigated the range expansion histories of Machilus thunbergii populations in the Kinki region of central Japan on the basis of nuclear microsatellite data. In the Kinki region, M. thunbergii is typically found in the coastal area, with some fragmented populations inland, around Lake Biwa. Phylogenetic and Bayesian clustering analysis (STRUCTURE analysis) revealed that the inland populations have different genetic components between the west and east sides of Lake Biwa. The population located on the north side of the lake has an admixture of the two genetically differentiated lineages, contributing to an increase in the genetic diversity of the population. Populations around Lake Biwa had lost rare alleles and the F value obtained from STRUCTURE analysis was lower in the coastal populations than in the lake populations. These results suggest that populations around Lake Biwa experienced a bottleneck due to a founder effect during the initial migration to the lake and that glacial refugia of M. thunbergii in the Kinki region existed along the coast. [ABSTRACT FROM AUTHOR]

Leaf surface features were investigated in the Tabu-No-Ki tree Machilus thunbergii by electron microscopy and white light scanning interferometry. Mature leaves of the tree were air-dried at room temperature and sputter-coated with platinum. The most prominent epicuticular wax structures of M. thunbergii leaves included granules, angular rodlets and transversely ridged rodlets. Wax granules were often observed on the adaxial leaf surface. Meanwhile, the abaxial leaf surface was characterized by transversely ridged rodlets in which the ridges were perpendicular to their longitudinal axis. Having several facets, the angular rodlets were straight and grew among clusters of transversely ridged rodlets. The adaxial leaf surface of M. thunbergii appeared to be smooth and less undulating than the abaxial leaf surface. Clusters of epicuticular waxes were predominant on the abaxial leaf surface. The average heights of the adaxial and abaxial leaf surfaces were 1.79 ± 0.58 and 3.65 ± 0.93 μm, respectively. The average roughness and root-mean-square roughness values were lower those on the adaxial surface than on the abaxial surface. These results suggest that the transversely ridged rodlets significantly contribute to the increased surface roughness on the abaxial leaf surface. [ABSTRACT FROM PUBLISHER]

Abstract: We monitored chlorophyll (Chl) fluorescence, pigment concentration and the de-epoxidation state of the xanthophyll cycle (DPS [1] DPS is defined as the ratio of (Z+A) to (V+A+Z), where Z, A and V stand for concentrations of zeaxanthin, antheraxanthin and violaxanthin, respectively. 1 ) in two warm temperate broad-leaved evergreen species (Quercus myrsinaefolia and Machilus thunbergii). Reduction of the maximal quantum yield of Photosystem II (PSII) (calculated from Fv/Fm, variable to maximal Chl a fluorescence) and retention of a high DPS were observed in both species in the winter, and can be interpreted as acclimation to winter. In particular, the acclimation of PSII in these species can be chiefly attributed to thermal dissipation, which is correlated with the retention of high zeaxanthin. Furthermore, we attempted to divide the fate of the absorbed light energy by the PSII antennae into three components: (i) PSII photochemistry (represented by its quantum yield, ΦPSII), (ii) dissipation by down-regulation via non-photochemical quenching (ΦNPQ) and (iii) other non-photochemical processes (ΦONP). The estimated energy allocation of the absorbed light indicated that the proportion of ΦPSII decreased, whereas that of ΦNPQ+ΦONP increased during winter. This result suggests that the excess energy absorbed in the PSII complexes is safely dissipated from the PSII antennae. Based on these results, we conclude that thermal dissipation from the PSII antennae plays an important role in two overwintering broad-leaved evergreen trees growing in Japan. [Copyright &y& Elsevier]

Two new dibenzylbutane lignans, namely rel-methyl (2S)-2-hydroxy-2-2'-((2''R,3''R)-4''-guaiacyl-2'',3''dimethylbutyl)-5'-oxo-2',5'-dihydro-2-furanylethnoate (1) and rel-methyl (2S)-2-hydroxy-2-2'-((2''R,3''S)-4''-guaiacyl-2'',3''dimethylbutyl)-5'-oxo-2',5'-dihydro-2-furanylethnoate (2), were isolated from the bark of Machilus thunbergii. Their structures were elucidated by spectral analysis. These two lignans exerted significant neuroprotective activities against glutamate-induced neurotoxicity in primary cultures of rat cortical cells. Compounds 1 and 2 represent a new type of lignan skeleton that has not been reported so far from nature. [ABSTRACT FROM AUTHOR]

The dichloromethane fraction of the bark of Machilus thunbergii Sieb. et Zucc. (Lauraceae) significantly protected primary cultures of rat cortical cells exposed to the excitotoxic amino acid, L-glutamate. Through the activity-guided isolation from the CH2Cl2 fraction, (+)-9′-hydroxygalbelgin ( 1), isogalcatin B ( 2), (7 S,8 S,8′ R)-3′,4′-dimethoxy-3,4,-methylenedioxylignan-7-ol ( 3), 1-hydroxy-7-hydroxymethyl-6-methoxyxanthone ( 4), 5,7-dimethoxy-3′,4′-methylenedioxyflavan-3-ol ( 5), (+)-(3 S,4 S,6 R)-3,6-dihydroxypiperitone ( 6), protocatechuic acid methyl ester ( 7) and tyrosol ( 8) were obtained. All of them had significant neuroprotective activities against glutamate-induced neurotoxicity in primary cultures of rat cortical cells at concentrations ranging from 0.1 μM to 10.0 μM and were comparable to MK-801, a well-known inhibitor of glutamate receptor. [ABSTRACT FROM AUTHOR]

Aim The purpose of this paper was to study the patterns of genetic variation, demographic history, haplotype relationships and potential location of diversity centres of two closely related species, Machilus thunbergii and Machilus kusanoi. Location The phylogeography of M. thunbergii and M. kusanoi was examined by sampling 110 and 106 individuals from 25 and 16 sampling sites, respectively, across their distributional range in Taiwan. Machilus thunbergii is distributed on the Asian mainland, South Korea, southern Japan, the Ryukyus, Taiwan and the Philippines, whereas M. kusanoi is endemic to Taiwan. These two species are closely related, and both are widely distributed in Taiwan but occupy different altitudinal zones and habitats. Methods The range-wide variation of M. thunbergii and M. kusanoi in Taiwan was studied using chloroplast DNA (cpDNA) variations. A haplotype network was constructed with the computer programtcs. Nested clade analysis was conducted with the computer programceodis, and various parameters of genetic diversity were calculated and neutrality tested by the computer program DnaSP. Population differentiation was estimated using the programsarlequin andhapstep. The contribution of the populations to gene diversity and to allelic richness was calculated using the softwarecontrib. The level of divergence for each population from the remaining populations was calculated as the mean value of pairwise FST for each population against the rest of the populations. Results Extremely low levels of genetic differentiation were found for both species. This result suggested that these two species probably survived in multiple relict refugia with different population sizes throughout the island during low-temperature periods of the Pleistocene. In addition, nested clade analysis (NCA) of cpDNA haplotypes indicated that restricted gene flow with isolation-by-distance characterized the recolonization after the Pleistocene by Tashueshan and Shiouhluan populations of M. thunbergii in the north-central area west of the Central Mountain Range (CMR). In contrast, NCA analysis indicated that a major diversity centre on the southern tip of the island (Kending population) and contiguous range expansion characterized the recolonization by M. kusanoi of northern areas along the east side of the CMR. The major diversity centres found for the two species examined were further supported by the results of the mean FST for individual populations in comparison with other populations, and of the contribution of the divergence component to the total diversity. Main conclusions This research supports the multiple relict refugia hypothesis for both species investigated. Populations of M. thunbergii at Shiouhluan and Tashueshan in the north-central area west of the CMR represent a diversity centre currently expanding its size. A diversity centre at the southern-edge population of M. kusanoi, and a contiguous range expansion from Kending, were found. These results indicate that the M. thunbergii populations at Tashueshan and Shiouhluan and the M. kusanoi population at Kending, and even Soukar, are evolutionarily significant units for conservation programmes. [ABSTRACT FROM AUTHOR]

Abstract: The effect of meso-dihydroguaiaretic acid (MDGA) on the staurosporine-induced neuronal apoptosis and its potential mechanism were investigated using primary cultures of rat cortical cells as an assay system. Treatment of MDGA at the concentrations of 0.1, 1.0 and 10μM significantly protected neuronal cells against Staurosporine-induced apoptosis. The neuroprotective activity of MDGA was the most potent at the concentration of 1.0μM and was not increased at higher concentration. MDGA reduced apoptotic characteristics induced by STS; MDGA reduced the condensed nuclei in staurosporine-injured rat cortical cells. MDGA diminished the calcium influx that accompanies the staurosporine-induced apoptosis, and inhibited the subsequent overproduction of reactive oxygen species and peroxide to the level of control cells. It also preserved cellular activity of superoxide dismutase, an antioxidative enzyme reduced by staurosporine insult. In addition, MDGA significantly inhibited caspase-3/7 activation and cytochrome c release. Taken together, these results suggested that MDGA protected neuronal cells against staurosporine-induced apoptosis through the inhibition of Ca2+ influx, cellular oxidation, cytochrome c release and caspase-3/7 activation. [Copyright &y& Elsevier]

Thirteen compounds were isolated from the CH2CI2 fraction of Machilus thunbergii as phospholipase Cγ1 (PLCγ1) inhibitors. These compounds were identified as nine lignans, two neolignans, and two flavans by spectroscopic analysis. Of these, 5,7-di- O-methyl-3′,4′-methylenated ( -)-epicatechin ( 12) and 5,7,3′-tri- O-methyl ( -)-epicatechin ( 13) have not been reported previously in this plant. In addition, seven compounds, machilin A ( 1), (-)-sesamin ( 3), machilin G ( 5), (+)-galbacin ( 9), licarin A ( 10), (-)-acuminatin ( 11) and compound 12 showed dose-dependent potent inhibitory activities against PLCγ1 in vitro with IC50 values ranging from 8.8 to 26.0 υM. These lignans, neolignans, and flavans are presented as a new class of PLCγ1 inhibitors. The brief study of the structure activity relationship of these compounds suggested that the benzene ring with the methylene dioxy group is responsible for the expression of inhibitory activities against PLCγ1. Moreover, it is suggested that inhibition of PLCγ1 may be an important mechanism for an antiproliferative effect on the human cancer cells. Therefore, these inhibitors may be utilized as cancer chemotherapeutic and chemopreventive agents. [ABSTRACT FROM AUTHOR]

Thymic stromal lymphopoietin (TSLP) plays an important role in the pathophysiology of various allergic diseases that are mediated by T helper cell type-2 (Th2) responses, including asthma and atopic dermatitis. The primary focus of this study was the identification of potent inhibitors of the TSLP signaling pathway for potential therapeutic use. The 80% methanol extract of Machilus thunbergii bark significantly inhibited the signal transducer and activator of transcription 5 (STAT5) phosphorylation in human mast cell (HMC)-1 cells. Through activity-guided isolation, three lignans (1–3) were obtained and identified as (+)-galbelgin (1), meso-dihydroguaiaretic acid (2), and machilin A (3). Among them, two lignans (1 and 2) significantly inhibited STAT5 phosphorylation and TSLP/TSLPR interaction, as determined by ELISA. Our results indicated that lignans isolated from M. thunbergii are a promising resource for the treatment of allergic diseases. [ABSTRACT FROM AUTHOR]

The invasion behavior of two climax species, Machilus thunbergii Sieb. et Zucc. and Castanopsis cuspidata (Thunb.) Schottky var. sieboldii (Makino) Nakai, was studied on the 1874 and 1962 lava flows on Miyakejima, Japan. On the 1962 lava, zoochorous M. thunbergii appeared almost only under crowns of pioneering Alnus sieboldiana Matsum, while bolochorous C. cuspidata var. sieboldii occurred only along the borders of the lava. The three species, A. sieboldiana, M. thunbergii and C. cuspidata var. sieboldii, corresponded, in order, to the temporal sequence of invasion in the boundary forest and the spatial sequence from margin to center on the 1962 lava. Seed or fruit dispersion is important in primary succession in the case of large disturbances. [ABSTRACT FROM AUTHOR]

During a survey of diseased plants on Wando Island, Korea from May to June 2020, a severe leaf spot disease was observed in the upper leaves of Japanese bay tree (Machilus thunbergii). Early symptoms were light blackish spots on the leaf surface and enlargement of older spots. Dry leaf spots surrounded with deep black margins were common throughout the plants. Symptomatic leaf samples were collected, and the causal pathogen was isolated on potato dextrose agar (PDA). Three fungal isolates (CMML20-1, CMML20-3, and CMML20-4) were cultured on PDA for morphological characterization at 25 °C in the darkness. Fungal colonies were circular, fast-growing, olivaceous to dark grey, and with abundant aerial mycelium. Sporulation was induced in 14 h-10 h light-dark conditions, and the conidia were single-celled, thin-walled with a smooth surface, ellipsoid with round apices, and measuring 17.5–20.5 (avg. 17.5) μm × 7.5–10.0 (7.9) μm. The morphological characteristics resembled those typical for Neofusicoccum parvum. Molecular identification was confirmed by partially sequencing the internal transcribed spacer (ITS) region and the translation elongation factor 1-α (EF1-α) genes. Pathogenicity tests were conducted on detached leaves and whole plants of M. thunbergii. High disease prevalence was observed, and Koch postulates were fulfilled. This is the first worldwide report of N. parvum causing leaf spots on Machilus thunbergii. [ABSTRACT FROM AUTHOR]

Premise of the study: Microsatellite markers were developed and characterized in a typically coastal, widespread, and dominant tree species of the evergreen broadleaf forests, Machilus thunbergii, for comparison of the genetic diversity and structure of inland populations surrounding the ancient Lake Biwa and coastal populations in Japan. Methods and Results: Eighteen polymorphic microsatellites of this species were isolated using an improved technique for isolating codominant compound microsatellite markers. These isolated loci provided compound simple sequence repeat (SSR) markers with polymorphisms of three to 19 alleles per locus, with an average of 10.9. The expected and observed within-population heterozygosities ranged from 0.16 to 0.86 and from 0.13 to 0.72, respectively. Conclusions: These markers may be useful tools for further investigation of the population genetic structure and biogeographic history of M. thunbergii in the warm-temperate zone of East Asia. [ABSTRACT FROM AUTHOR]

Mature galls induced by Daphnephila truncicola, D. taiwanensis, D. sueyenae, D. stenocalia, and D. ornithocephala on Machilus thunbergii in northern Taiwan were examined to verify the dictum that the morphology of galls is an expression of the extended phenotype of the respective gall-inducing insect. Based on their length-width ratio, the materials were grouped into either fleshy (those induced by D. taiwanensis and D. sueyenae) or slim galls (those induced by D. truncicola, D. stenocalia, and D. ornithocephala). Stem galls induced by D. truncicola showed an energy level of 0.0178 kJ/g. Among leaf galls, the greatest energy level was in the one induced by D. stenocalia (0.0193 kJ/g), followed by D. sueyenae (0.0192 kJ/g), D. taiwanensis (0.0189 kJ/g), and D. ornithocephala (0.0160 kJ/g). The numbers of reserve and nutritive cell layers in galls were greater in the stem galls induced by D. truncicola, similar to those in the fleshy leaf galls, than in the slim leaf galls. Based on the fungal taxa isolated from the larval chambers and considering the similarities and divergences among gall characteristics, the galls induced by D. truncicola and D. taiwanensis clustered into one, whereas those of D. sueyenae aligned with the 'D. stenocalia-D. ornithocephala' cluster. The present study verified that shapes, structure, nutritive tissues, energy levels, and multiple coexisting fungal taxa within galls reinforce that they are extended phenotypes of the respective gall-inducing Daphnephila species and they represent adaptive evolution of Daphnephila on M. thunbergii.