Chemical constituents from Aphanamixis grandifolia

Four new terpenoids, nemoralisins D–G (1–4), were isolated from the leaves and stems of Aphanamixis grandifolia, along with two known diterpenoids, nemoralisin C and nemoralisin. Among them, compound 1 is the first example of norsesquiterpenoid with δ-lactone moiety, and nemoralisins E–G (2–4), are a class of acyclic diterpenoids, which are structurally related nemoralisin C and nemoralisin. These structures were established on the basis of spectroscopic methods and the absolute configuration of 1 was determined by comparison of quantum chemical TDDFT calculated and experimental ECD spectra. Nemoralisins D–G (1–4) were tested for their cytotoxicities on HL-60, SMMC-7721, A-549, MCF-7, and SW480 human tumor cell lines (IC₅₀ > 40 μM), as well as the antimicrobial activities on Staphylococcus aureus, Pseudomonas aeruginosa, MRSA92^# and MRSA98^# (MIC > 50 μg/mL).     

Estrogenic and anti-estrogenic activities of hispolon from Phellinus lonicerinus (Bond.) Bond. et sing

Hispolon was the main antitumor active ingredient in Phellinus sensu lato species. In order to confirm the dual regulating estrogenic ingredient and obtain more effective natural estrogen replacement drugs, hispolon was separated from Phellinus lonicerinus (Bond.) Bond. et sing. Hispolon exhibited significant anti-proliferative effect against estrogen-sensitive ER (+) MCF-7 cells in the absence of estrogen, and exhibits antagonistic effects on 17β-estradiol (E₂)-induced MCF-7 cell proliferation when E₂ and the different concentrations of hispolon were treated simultaneously. Hispolon also inhibited the proliferation of estrogen-negative ER (−) MDA-MB-231 cells at the concentration of 5.00 × 10^− 5 M. The yeast two-hybrid experiments showed that hispolon had strong and non-selective effects on the estrogen receptor (ER) α and ERβ at a concentration of 1.00 × 10^− 6 M. The ERβ-binding ability of hispolon was larger than ERα in the concentration range of 1.00 × 10^− 9 M and 1.00 × 10^− 7 M. Hispolon could increase the body weight coefficient, serum E₂ and progesterone contents in immature female mice at dose of 9.10 × 10^− 6 mol/kg, and increase coefficient of thymus and spleen in mice. The Gscores of hispolon-ERα and hispolon-ERβ docked complexes were − 7.93 kcal/mol and − 7.79 kcal/mol in docking simulations. Hispolon presented dual regulating estrogenic activities, which showed estrogenic agonist activity at low concentration or lack of endogenous estrogen, and the estrogenic antagonistic effect was stimulated at high concentrations or too much endogenous estrogen. Hispolon could be used for treating the estrogen deficiency-related disease with the benefit of non-toxic to normal cells, good antitumor effects and estrogenic activity.     

Sesquiterpene coumarin and sesquiterpene chromone derivatives from Ferula ferulaeoides (Steud.) Korov.

Five novel compounds — three sesquiterpene coumarin derivatives, ferulin A (1), B (2), and C (3), and two sesquiterpene chromone derivatives, ferulin D (4) and E (5), together with eleven known compounds (6–16) have been isolated from the roots of Ferula ferulaeoides (Steud.) Korov. Their structures were established by comprehensive spectroscopic analysis. The biosynthetic pathways leading to these compounds were proposed. The cytotoxicity of all these isolates against HepG2, MCF-7, and C6 cancer cell lines was evaluated and compound 7 displayed the highest potency against HepG2, MCF-7, and C6 with IC₅₀ values 39.9 μM, 37.7 μM, and 16.0 μM, respectively.     

Dynamics of above- and below-ground biomass and nutrient accumulation in an age sequence of Nothofagus antarctica forest of Southern Patagonia

Nothofagus antarctica (Forster f.) Oersted is a deciduous tree species, which naturally grows on poorly drained or drier eastern sites in the Andes Mountain near Patagonian steppe. Above- and below-ground biomass and nutrients pools were measured in pure even-aged stands at different ages (5–220 years) and crown classes. Functions were fitted for total biomass and nutrients accumulation, and root/shoot ratio of individual trees against age. Total biomass accumulated for mature dominant trees was eight times greater than mature suppressed trees. Biomass root/shoot ratio decreased with age from 1.8 to a steady-state of 0.5. All nutrients concentration (except Ca) decreased with age and varied according to the degree of crown suppression classes. Nutrient concentrations varied between biomass pool components following the order leaves > bark > small branches > fine roots > medium roots > rooten wood > coarse roots > sapwood > heartwood. Total nutrient accumulation followed the order dominant > codominant > intermediate > suppressed trees and its accumulation rate varied over time, e.g. P accumulation rate of dominant trees increased from 0.17 g tree⁻¹ year⁻¹ during regeneration to 1.39 g tree⁻¹ year⁻¹ in mature trees. Nutrients uptake reached a peak during the period of maximum biomass production, and root/shoot ratio of nutrients decreased from its maximum value at 5 years of age (0.6, 4.0, 0.9, 1.5, 1.0 and 2.6 for N, P, K, Ca, S and Mg, respectively) to a steady-state asymptote beyond 50 years of age. Thus, accumulation of nutrients in roots was greater during the regeneration phase of stand development, and nutrient accumulation increased in above-ground over time. Also, nutrient use efficiency increased in mature trees (111–220 years) and decreased in suppressed crown classes. The equations developed for individual trees have been used to estimate stand biomass and nutrient accumulation from forest inventories data. Total stand biomass varied from 62.5 to 133.4 t ha⁻¹ and total nutrients accumulation ranged from 3 kg Mg ha⁻¹ to 1235 kg Ca ha⁻¹. Proposed equations can be used for practical purposes such as to estimate pasture nutrients requirement in a silvopastoral system based on nutrients supply from leaf litter returns, or to determine amelioration practices like debarking stems before harvesting.     

Comparison of in vitro antiviral activity of tea polyphenols against influenza A and B viruses and structure–activity relationship analysis

Influenza poses a particular risk of severe outcomes in the elderly, the very young and those with underlying diseases. Tea polyphenols are the natural phenolic compounds in teas, and principally consist of catechins, proanthocyanidins, flavonols, and theaflavins, which antiviral activities have been reported recently. This study is to gain a further insight into potential of various tea polyphenols for inhibiting influenza virus infection. Five tea polyphenols exhibited inhibitory activity against influenza A virus in the trend of theaflavin > procyanidin B-2 > procyanidin B-2 digallate > (−)-epigallocatechin(EGC) > (−)-epigallocatechingallate(EGCG) with IC₅₀ values in the range of 16.2–56.5 μg/ml. Six of the tested compounds showed anti-influenza B virus activity in the order of kaempferol > EGCG > procyanidin B-2 > (−)-EGC ~ methylated EGC > theaflavin with IC₅₀ values in the range of 9.0–49.7 μg/ml. Based on these results, the structure–activity relationship (SAR) was explained as follows. First, the dimeric molecules, such as theaflavin and procyanidin B-2, generally displayed more potent antiviral activity against both influenza A and B viruses than the catechin monomers. Second, the kaempferol for inhibition of influenza B virus indicated that the more planar flavonol structure with only one C-4′ phenolic hydroxyl group in the B ring is necessary for the anti-influenza B virus activity. A similar SAR can be drawn from the assays of another enveloped RNA virus, such as respiratory syncytial virus. These results are expected to provide guides for rational design of antiviral drugs based on polyphenols.     

New cytotoxic compounds from flowers of Lawsonia inermis L.

Three new compounds, a bicoumarin A (1), a biflavonoid A (2), and a biquinone A (3), as well as 12 other known compounds, were isolated from the flower of Lawsonia inermis L. The structures were elucidated by spectral analysis and new compounds 2 and 3 then were further confirmed by ECD calculations and single-crystal X-ray diffraction crystallography respectively. The cytotoxicity of the compounds against four cancer cell lines, including MCF-7, Hela, HCT-116, and HT-29 were evaluated using MTT assay. The IC₅₀ values of compounds 3 and 5 against MCF-7, Hela, HCT-116, and HT-29 were 2.24, 1.42, 24.29, and 7.02 μM and 6.1, 2.44, 5.58, and 10.21 μM respectively. The two compounds exhibited stronger inhibitory activities than the positive control 5-fluorouracil (IC₅₀ = 7.34, 11.50, 36.17, 18.83 μM) against the four tested cell lines. These results demonstrated that compounds from the flowers of L. inermis L. showed cytotoxic activity on MCF-7, Hela, HCT-116, and HT-29 cell lines.     

Triterpenoids of sour jujube show pronounced inhibitory effect on human tumor cells and antioxidant activity

Sour jujube is a common fruit and traditional medicine in China. Bioactivity-guided fractionation of sour jujube was used to determine the chemical identity of potent antiproliferative and antioxidant constituents. Four novel ursane-type triterpenoids, together with 8 known were isolated and identified. The new triterpenoids were elucidated to be 2α,3β,13β,23-tetrahydroxy-urs-11-en-28-oic acid (3), 2α,3β-dihydroxy-urs-20(30)-en-28-oic acid (9), 2α,3β,28-trihydroxy-urs-20(30)-ene (10), and 3β,12β,13β-trihydroxy-ursan-28-oic acid (11). Among the triterpenoids isolated, 2α,3β,19α-trihydroxy-urs-12-en-28-oic acid (7), 9 and 10 showed high potent inhibitory activity toward the proliferation of HepG2 cells, which the IC₅₀ values were lower than 5 μM. Compounds 9 and 10 also exhibited pronounced activity against MCF-7 cells, with IC₅₀ value of 0.8 ± 0.03 and 1.5 ± 0.1 μM, respectively. Compound 10 showed high antioxidant activity with an EC₅₀ of 0.8 ± 0.02 μM, which was 18.9 times higher than ascorbic acid in antioxidant capacity.     

Three new phenolic compounds from the leaves of Rosa sericea

Two new flavonoids, quercetin-3-O-β-d-xylopyranosyl-(1 → 2)-α-d-ribopyranoside (1) and kaempferol-3-O-β-d-xylopyranosyl-(1 → 2)-α-d-ribopyranoside (2), and one new phenolic derivative, gallicin-p-O-(6′-O-caffeoyl)-β-d-glucoside (3), together with twelve known compounds were isolated from the leaves of Rosa sericea (Rosaceae family). The structures of the new compounds were established by means of spectroscopic analysis including one- and two-dimensional NMR spectroscopy. Some of the isolated compounds were tested for the cytotoxicity of a breast cancer cell (MCF-7) line. The results showed that rubanthrone A (4) has moderate cytotoxicity against the MCF-7 cell line.     

New lignans from the bioactive fraction of Sambucus williamsii Hance and proliferation activities on osteoblastic-like UMR106 cells

Four new lignans (1, 7–9), together with nine known ones, were isolated from the anti-osteoporosis fraction of the extract of Sambucus williamsii Hance which was eluted by 50% and 95% aqueous ethanol over D101 macroporous resin column. Their structures were elucidated by NMR spectroscopic analyses, and the absolute configurations of all compounds were determined by application of circular dichroism method. All the compounds were reported for the first time from the Sambucus genus and firstly studied for their proliferation effects on osteoblastic-like UMR 106 cell. The data showed that compounds 2–9 significantly promoted cell proliferation in some dose, especially compounds 2, 3, 4, 5, and 7 increased osteoblastic cell numbers by 31.3%, 28.3%, 25.6%, 25.1% and 26.0% at 10^− 10 M, 10^− 10 M, 10^− 7 M, 10^− 10 M and 10^− 10 M, respectively, which suggested that lignans were the components accounting for the bone protective effects of SWH.     

Hormone-sensitive lipase is involved in the action of hydroxysafflor yellow A (HYSA) inhibiting adipogenesis of 3T3-L1cells

BackgroundSafflor yellow A (SY) has been demonstrated to be beneficial to cardiovascular system. Our previous study showed that hydroxysafflor yellow A (HSYA), a main component of SY, could increase peroxisome proliferator-activated receptor γ mRNA expression. In this study, we investigate the effect of HSYA on the proliferation and adipogenesis of mouse 3T3-L1 preadipocytes.MethodsThe proliferation and adipogenesis of 3T3-L1 cells treated with HSYA was studied by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide (MTT) spectrophotometry, Oil Red O staining and intracellular triglyceride assay methods. HSL mRNA expression and promoter activity were studied by real-time quantitative RT-PCR, transient transfection and dual luciferase reporter gene methods.ResultsHSYA (0.1 mg/L) significantly inhibited the proliferation of 3T3-L1 cells when compared with control cells in 8 h. This effect was further enhanced with the extension time (24 to 96 h) and an increase of concentration of HSYA (1–10 mg/L). The maximal inhibitory action was observed at 0.1 mg/L HSYA in 72 h (86 ± 11.8% vs. 100 ± 4.1%, p < 0.01). HSYA notably reduced the amount of intracellular lipid and triglyceride content in adipocytes to 85% (1 mg/L) and 75% (100 mg/L) on Day 4 following the differentiation, respectively, while increased HSL mRNA expression and promoter activities to 2.7 fold and 1.55 fold, respectively (p < 0.01), in differentiated 3T3-L1 adipocytes.ConclusionsHSYA inhibits the proliferation and adipogenesis of 3T3-L1 preadipocytes. The inhibitory action of HYSA on adipogenesis may be due to the promotion of lipolytic-specific enzyme HSL expression by increasing HSL promoter activity.     

Nitrate concentrations in soil solutions below Danish forests

Nitrate in the soil water below the root zone is a pre-condition for nitrate leaching, and it indicates loss of nutrients from the forest ecosystem. Nitrate leaching may potentially cause eutrophication of surface water and contamination of ground water. In order to evaluate the extent of nitrate leaching in relation to land-use, a national monitoring programme has established sampling routines in a 7×7 km grid including 111 points in forests. During winters of 1986–1993, soil samples were obtained from a depth of 0–25, 25–50, 50–75 and 75–100 cm. Nitrate concentrations in soil solutions were determined by means of a 1 M KCl extraction. The influence of forest size, forest-type, soil-type, tree species and sampling time on the nitrate concentrations was analysed in a statistical model. The analysis focused on data from depth 75–100 cm, as nitrate is considered potentially lost from the ecosystem at this depth. The range of nitrate concentrations was 0–141 mg NO⁻₃–N dm⁻³ and the estimated mean value was 1.51 mg NO⁻₃–N dm⁻³. The concentration was influenced by (1) forest size (concentrations in forests <10 ha were higher than concentrations in forests >50 ha), (2) forest-type (afforested arable land had higher concentrations than forest-type `other woodland'), (3) soil-type (humus soils showed above average concentrations, and fine textured soils had higher concentrations than coarse textured soils), and (4) sampling time. Unlike other investigations, there was no significant effect of tree species. A few sites deviated radically from the general pattern of low concentrations. The elevated concentrations recorded there were probably caused by high levels of N deposition due to emission from local sources or temporal disruptions of the N cycle. The nitrate concentration in the soil solution below the root zone was mostly rather low, indicating that, generally, N saturation has not yet occurred in Danish forest ecosystems. However, median concentrations exceeding drinking water standards (11.3 mg NO⁻₃–N dm⁻³) were found at 7% of the sites. Furthermore, 30% of the sites had median concentrations above 2 mg NO⁻₃–N dm⁻³, suggested as an elevated level for Danish forest ecosystems, equalling annual N losses of more than 2–6 kg ha⁻¹ year⁻¹.     

Isocoumarins from American cockroach (Periplaneta americana) and their cytotoxic activities

Four new isocoumarins (1–4), along with three known ones (5–7), were isolated from the 70% ethanol extract of the whole body of the traditional Chinese insect medicine, American cockroach (Periplaneta americana). The structures with absolute configurations of new compounds were elucidated by extensive spectroscopic methods in combination with X-ray diffraction experiment and CD analyses. Compounds 3–5 showed significant cytotoxic activities in HepG2 and MCF-7 cells with IC₅₀ values in the ranges 6.41–23.91 μM and 6.67–39.07 μM, respectively.     

Phytochemical investigation of sesquiterpenes from the fruits of Schisandra chinensis and their cytotoxic activity

Phytochemical investigation of ethanolic extract from the fruits of Schisandra chinensis led to the isolation of four new sesquiterpenes (1–4); their structures were determined by a combination of NMR (1D and 2D) and MS spectroscopic techniques. In addition, all these isolates were screened for their cytotoxic activities against MCF-7, Caco-2, Hela, Lncap, Hep G2 and MDA-MB231 cancer cell lines. Results indicated that compounds 2 and 3 displayed potent cytotoxic activity against Caco2 cell lines with IC₅₀ values of 17.10 μg/mM and 16.46 μg/mM, respectively.     

Effect of spacing and water availability on root:shoot ratio in Eucalyptus camaldulensis

Our limited understanding of the processes that control the allocation of biomass in trees is one of the factors that hinders our ability to develop mechanistic models of tree growth. Furthermore, accurate assessment of carbon sequestration by forests is hampered by lack of information regarding below-ground biomass. Below-ground to above-ground biomass ratios (BGB:AGB) are known to vary with a number of environmental factors, tending to increase in drier, harsher conditions. However, there are few, good datasets of BGB:AGB ratios of large trees, especially native Australian species. We aimed to investigate the response of BGB:AGB to water availability and tree spacing in 10-year-old Eucalyptus camaldulensis growing in a plantation in a low rainfall area.We carefully harvested 16 trees, ranging in diameter at breast height (DBH) from 7.6 to 25 cm, from a research trial near Deniliquin, NSW. Four replicates of each treatment from a factorial design with wide (3 m × 6 m) and narrow (3 m × 1.5 m) spaced trees and with natural rainfall (408 mm/year) (control) or irrigated plots (flooded six times per year) were selected. Above-ground tree parts were harvested separating stem, branch and foliage. Soil cores to 1 m depth were taken to sample small roots (<15 mm diameter) within each plot, then all roots >15 mm belonging to each tree were excavated using compressed air and an excavator. Roots were separated into six size classes within the range from <2 to >50 mm.Both water and spacing treatments influenced tree growth with trees being larger in irrigated, wide spaced plots. The BGB:AGB ratio was strongly influenced by irrigation (0.68 control, 0.34 irrigated) but not spacing. Allometric analysis of above- and below-ground biomass as a function of DBH showed that the relationship between DBH and above-ground biomass was conserved across treatments.By contrast, the relationship between DBH and below-ground biomass was influenced by water availability, commensurate with the large differences in BGB:AGB ratio. The BGB:AGB ratio increased with tree size largely due to an increase in small roots.The proportion of total root mass in the small roots (<15 mm) obtained through coring was 25–48% with 18–30% of total root biomass in the <5 mm diameter class.     

Anti-HIV-1 tigliane diterpenoids from Excoecaria acertiflia Didr

Three tigliane-type diterpenoids named excoecafolins A–C and two daphnane-type diterpenoids named excoecafolins D and E, together with 13 known compounds, were isolated from the EtOAc extract of Excoecaria acerifolia Didr. Their structures were elucidated through the analysis of the spectroscopic data. The anti-HIV-1 activity evaluation of five of these compounds showed that four possessed moderate anti-HIV-1 activities with EC₅₀ 0.258, 0.036, 0.046, and 0.978 μM, SI > 1,836.9, 431.1, 298.7, and > 503.7, respectively. Additionally, the chemotaxonomic issue of the affinity correlation between Thymelaeceae and Euphorbiaceae is discussed based on the isolates.     

Necromass in undisturbed and logged forests in the Brazilian Amazon

Necromass is an important stock of carbon in tropical forests. We estimated volume, density, and mass of fallen and standing necromass in undisturbed and selectively logged forests at Juruena, Mato Grosso, Brazil (10.48°S, 58.47°W). We also measured standing dead trees at the Tapajos National Forest, Para, Brazil (3.08°S, 54.94°W) complementing our earlier study there on fallen necromass. We compared forest that was selectively logged using reduced-impact logging methods and undisturbed forest. We estimated necromass density accounting for void volume for necromass greater than 10 cm diameter at Juruena for five decay classes that ranged from freshly fallen (class 1) to highly decayed material (class 5). Average necromass density adjusted for void space (±S.E.) was 0.71 (0.02), 0.69 (0.04), 0.60 (0.04), 0.59 (0.06), and 0.33 (0.05) Mg m⁻³ for classes 1 through 5, respectively. Small (2–5 cm) and medium (5–10 cm) size classes had densities of 0.52 (0.02) and 0.50 (0.04) Mg m⁻³, respectively. The average dry mass (±S.E.) of fallen necromass at Juruena was 44.9 (0.2) and 67.0 (10.1) Mg ha⁻¹ for duplicate undisturbed and reduced impact logging sites, respectively. Small and medium sized material together accounted for 12–21% of the total fallen necromass at Juruena. At Juruena, the average mass of standing dead was 5.3 (1.0) Mg ha⁻¹ for undisturbed forest and 8.8 (2.3) Mg ha⁻¹ for forest logged with reduced impact methods. At Tapajos, standing dead average mass was 7.7 (2.0) Mg ha⁻¹ for undisturbed forest and 12.9 (4.6) Mg ha⁻¹ for logged forest. The proportion of standing dead to total fallen necromass was 12–17%. Even with reduced impact harvest management, logged forests had approximately 50% more total necromass than undisturbed forests.     

Pharmacokinetic study of eight coumarins of Radix Angelicae Dahuricae in rats by gas chromatography–mass spectrometry

A sensitive, specific gas chromatography–mass spectrometry (GC–MS) method was established for the quantitative determination of eight coumarins of Radix Angelicae Dahuricae including coumarin, isopsoralen, psoralen, xanthotoxin, bergapten, osthole, imperatorin and oxypeucedanin in rat plasma. Nitrendipine was used as the internal standard (IS). The plasma samples were extracted by acetonitrile. GC separation was accomplished on a DB-5MS column with temperature programmed from 160 °C (17 min) to 190 °C (10 min) at the rate of 20 °C/min, then to 240 °C (5 min) at 20 °C/min, and finally to 280 °C (14 min) at 20 °C/min. The detection was performed on a quadrupole mass spectrometer detector operated by full-scan mode (m/z 50–500). The lower limit of quantitation was 5–10 ng/mL for eight coumarins, and the linear range was 5–1000 ng/mL for the coumarins (R² > 0.9990). All the validation data were within the required limits. After oral administration, the plasma concentration–time curves showed that the time for maximum concentration (T_max) was 1.29 for coumarin, 1.83 for isopsoralen, 1.93 for psoralen, 1.30 for xanthotoxin, 2.04 for bergapten, 0.64 for osthole, 1.41 for imperatorin and 0.51 h for oxypeucedanin. The plasma concentration of the eight coumarins was low, with a mean maximum plasma concentration (C_max) < 6.41 μg/mL. Pharmacokinetic data analysis showed that the eight coumarins had different pharmacokinetic characteristics after oral administration. The method was successfully applied to pharmacokinetic studies of eight coumarins after oral administration in rats.     

Biomass,harvestable area,and forest structure estimated from commercial timber inventories and remotely sensed imagery in southern Amazonia

The purpose of this study was to determine if spatially-explicit commercial timber inventories (CTI) could be used in conjunction with satellite imagery to improve timber assessments and forest biomass estimates in Amazonia. As part of a CTI, all commercial trees ≥45 cm DBH were measured and georeferenced in 3500 ha of a logging concession in NW Mato Grosso, Brazil. A scientific inventory was conducted of all trees and palms ≥10 cm DBH in 11.1 ha of this area. A total of >20,000 trees were sampled for both inventories. To characterize vegetation radiance and topographic features, regional LANDSAT TM and ASTER images were obtained. Using a stream network derived from the ASTER-based 30 m digital elevation model (DEM), a procedure was developed to predict areas excluded from logging based on reduced impact logging (RIL) criteria. A topographic index (TI) computed from the DEM was used to identify areas with similar hydrologic regimes and to distinguish upland and lowland areas. Some timber species were associated with convergent landscape positions (i.e., higher TI values). There were significant differences in timber density and aboveground biomass (AGB) in upland (6.0 stems ha⁻¹, 33 Mg ha⁻¹) versus lowland (5.4 stems ha⁻¹, 29 Mg ha⁻¹) areas. Upland and lowland, and timber and non-timber areas could be distinguished through single and principal component analysis of LANDSAT bands. However, radiance differences between areas with and without commercial timber on a sub-hectare scale were small, indicating LANDSAT images would have limited utility for assessing commercial timber distribution at this scale. Assuming a 50 m stream buffer, areas protected from logging ranged from 7% (third order streams and above) to 28% (first order and above) of the total area. There was a strong positive relationship between AGB based on the scientific inventory of all trees and from the commercial timber, indicating that the CTI could be used in conjunction with limited additional sampling to predict total AGB (276 Mg ha⁻¹). The methods developed in this study could be useful for facilitating commercial inventory practices, understanding the relationship of tree species distribution to landscape features, and improving the novel use of CTIs to estimate AGB.     

The inhibition of resveratrol to human skin squamous cell carcinoma A431 xenografts in nude mice

Squamous cell carcinoma (SCC) is one of the commonest dermatological malignancies. Resveratrol (Res) is one type of polyphenolic compound which was first identified from the roots of Veratrum grandinorum in 1940. The previous studies found that Res can promote apoptosis of a variety of tumor cell, especially SCC cells. However it is rare to study the inhibition mechanism of Res in the animal model. In this study, through the establishment of human cutaneous SCC A431 xenografts in nude mice, we observed Res inhibition effect and investigated the inhibition mechanism by checking the expression of apoptosis-related factors, p53, ERK and survivin. The results showed that the xenograft volume and weight of Res groups were less than those of the control groups (P < 0.05), but the net body mass of nude mice of Res groups was not significantly different from the control groups (P > 0.05). The apoptotic index of Res groups were significantly higher than the control groups (P < 0.05). The protein and mRNA expression of p53 and ERK were statistically positively correlated (P < 0.05) and significantly increased in Res high- and medium-dose groups compared with the control groups (P < 0.05). Moreover, the protein and mRNA expression of SVV were negatively correlated with p53 (P < 0.05) and lower than the control groups (P < 0.05). The results demonstrate Res inhibitory effect and indicate that the inhibition mechanism of Res is to upgrade the protein and mRNA expression of p53 and to downgrade the protein and mRNA expression of SVV, thus inducing the apoptosis of tumor cells.     

Ponderosa pine snag densities following multiple fires in the Gila Wilderness,New Mexico

Fires create and consume snags (standing dead trees), an important structural and ecological component of ponderosa pine forests. The effects of repeated fires on snag densities in ponderosa pine forests of the southwestern USA have not been studied. Line intercept sampling was used to estimate snag densities in areas of the Gila Wilderness that had burned one to three times under Wildland Fire Use for Resource Benefit (WFU), a fire management policy implemented since 1974 aimed at restoring natural fire regimes. Twenty randomly located transects were measured in areas burned since 1946; six in once-burned areas, six in twice-burned areas and eight in thrice-burned areas. The mean density ± standard errors of large (>47.5 cm dbh) snags for areas that burned once, twice and thrice was 7.0 ± 2.7, 4.4 ± 1.1 and 4.1 ± 1.3 snags/ha, respectively. Differences in snag densities between once- and multiple-burned areas were significant (F-test; p < 0.05). There was no significant difference in density of large snags between twice- and thrice-burned areas. Proportions of type 1 snags (recently created) were higher in once- and twice-burned areas than in areas that burned three times, likely reflecting high tree mortality and snag recruitment resulting from an initial entry fire. Type 3 snags (charred by previous fire) were more abundant in areas that burned multiple times. The lack of differences in snag densities between areas that burned two and three times suggests that repeated fires leave many snags standing. The increasing proportion of type 3 snags with repeated fires supports this conclusion.