Search Results (5)

Phellinus noxius is a highly destructive fungus that causes brown root disease in trees, leading to decay and death. In Taiwan, five prized woods—Taiwania cryptomerioides, Calocedrus macrolepis var. formosana, Cunninghamia lanceolata var. konishii, Chamaecyparis formosensis, and Chamaecyparis obtusa var. formosana—are known for their fragrance and durability. This study aims to explore the anti-brown-root-rot-fungus activity of Cunninghamia lanceolata var. konishii (CL) essential oil (CLOL) and its primary components, while also delving into their mechanisms of action and inhibition pathways. The essential oil (CLOL) from CL wood demonstrated significant efficacy against P. noxius, with an inhibitory concentration (IC₅₀) of 37.5 µg/mL. Cedrol, the major component (78.48%) in CLOL, emerged as a potent antifungal agent, surpassing the reference drug triflumizole. Further assays with cedrol revealed a stronger anti-brown-root-disease activity (IC₅₀ = 15.7 µg/mL) than triflumizole (IC₅₀ = 32.1 µg/mL). Scanning electron microscopy showed deformation and rupture of fungal hyphae treated with CLOL and cedrol, indicating damage to the fungal cell membrane. Cedrol-induced oxidative stress in P. noxius was evidenced by increased reactive oxygen species (ROS) levels, leading to DNA fragmentation, mitochondrial membrane potential reduction, and fungal apoptosis through the mitochondrial pathway. Gel electrophoresis confirmed cedrol-induced DNA fragmentation, whereas TUNEL staining demonstrated increased apoptosis with rising cedrol concentrations. Moreover, protein expression analysis revealed cedrol-triggered release of cytochrome c, activation of caspase-9, and subsequent caspase-3 activation, initiating a caspase cascade reaction. This groundbreaking study establishes cedrol as the first compound to induce apoptosis in P. noxius while inhibiting its growth through oxidative stress, an increase in mitochondrial membrane permeability, and activation of the mitochondrial pathway. The findings offer compelling evidence for cedrol’s potential as an effective antifungal agent against the destructive brown root disease caused by P. noxius. Full article

Subtropical montane peatland is among several rare ecosystems that continue to receive insufficient scientific exploration. We analyzed the vegetation types and soil bacterial composition, as well as surface carbon dioxide and methane fluxes along a successional peatland-to-upland-forest series in one such ecosystem in Taiwan. The Yuanyang Lake (YYL) study site is characterized by low temperature, high precipitation, prevailing fog, and acidic soil, which are typical conditions for the surrounding dominant Chamaecyparis obtusa var. formosana forest. Bacterial communities were dominated by Acidobacteriota and Proteobacteria. Along the bog-to-forest gradient, Proteobacteria decreased and Acidobacteriota increased while CO₂ fluxes increased and CH₄ fluxes decreased. Principal coordinate analysis allowed separating samples into four clusters, which correspond to samples from the bog, marsh, forest, and forest outside of the watershed. The majority of bacterial genera were found in all plots, suggesting that these communities can easily switch to other types. Variation among samples from the same vegetation type suggests influence of habitat heterogeneity on bacterial community composition. Variations of soil water content and season caused the variations of carbon fluxes. While CO₂ flux decreased exponentially with increasing soil water content, the CH₄ fluxes exhibited an exponential increase together with soil water content. Because YYL is in a process of gradual terrestrialization, especially under the warming climate, we expect changes in microbial composition and the greenhouse gas budget at the landscape scale within the next decades. Full article

Both Chamaecyparis formosensis and C. obtusa var. formosana are representative cypresses of high economic value in Taiwan, the southernmost subtropical region where cypresses are found. Both species show differences of their habitats. To find out the effects of environmental factors on the CO₂ assimilation rate and the biogenic volatile organic compound (BVOC) emission of both species, saplings from both species were grown under different light intensity and temperature regimes. The results indicated that the net CO₂ assimilation rates and total BVOC emission rates of both species increased with increasing light intensity. C. formosensis showed a higher magnitude of change, but C. obtusa var. formosana had considerably increased sesquiterpenoid and diterpenoid emission in BVOC under high light intensity. Both species grown under higher temperatures had significantly lower BVOC emission rates. Proteomic analyses revealed that compared to C. formosensis saplings, C. obtusa var. formosana saplings had less differentially expressed proteins in terms of protein species and fold changes in response to the growth conditions. These proteins participated mainly in photosynthesis, carbon metabolism, amino acid and protein processing, signal transduction, and stress mechanisms. These proteins might be the major regulatory factors affecting BVOC emission of these two species under different environments. Full article

Seven new compounds, including one dimer novel skeleton, chamaecyformosanin A (1); three diterpenes, chamaecyformosanins B–D (2–4); one sesquiterpene, chamaecyformosanin E (5); and two monoterpenes, chamaecyformosanins F and G (6 and 7) were isolated from the methanol extract of the bark of Chamaecyparis obtusa var. formosana. Their structures were established by the mean of spectroscopic analysis and the comparison of NMR data with those of known analogues. Their structures were elucidated on the basis of physicochemical evidence, in-depth NMR spectroscopic analysis, and high-resolution mass spectrometry. Furthermore, the isolated compounds were subjected to an evaluation of their antimicrobial activity. Metabolites 1, 3, and 4 present antibacterial activities. It is worth mentioning that the chemical composition of the bark of C. obtusa var. formosana has never been studied in the past. This is the first time the barks from C. obtusa var. formosana were studied and two new skeleton compounds, 1 and 7, were obtained. Full article