Effects of salt stress on root morphology, carbon and nitrogen metabolism, and yield of Tartary buckwheat.

This study aims to clarify the effects of different concentrations of sodium chloride on the carbon and nitrogen metabolism and yield of Tartary buckwheat. The salt-sensitive cultivar Yunqiao 2 was pot-grown and treated with four salt concentrations including 0, 2, 4, and 6 g kg-1. The root morphology index increased from seedling stage to maturate stage. The content of soluble protein in the leaves reached the maximum at the anthesis stage, and the other substances content and the enzymes activity related to carbon and nitrogen metabolism reached the maximum at the grain filling stage. The root morphology index, root activity; invertase, amylase, sucrose synthase, and sucrose phosphate synthase activities; nitrate-nitrogen, ammonium nitrogen, and soluble protein content; and nitrate reductase and glutamate synthase activities increased first and reached the maximum at 2 g kg-1 treatment and then decreased with increasing salt stress concentration. The content of soluble sugars and sucrose and the activity of glutamate dehydrogenase increased continuously with increasing salt concentration, and reached the maximum in the 6 g kg-1 treatment. The grain number per plant, 100-grain weight, and yield per plant increased first and reached the maximum at 2 g kg-1 treatment and then decreased with increasing salt stress concentration. In summary, moderate salt stress (2 g kg-1) can promote the root growth, increase the content of carbon and nitrogen metabolism-related substances and enzyme activity, and increase the yield per plant of Tartary buckwheat.

Antiplatelet, cytotoxic activities and characterization of green-synthesized zinc oxide nanoparticles using aqueous extract of Nephrolepis exaltata.

The goal of the current study was to synthesize zinc oxide nanoparticles (ZnO-NPs) using ZnCl2.2H2O salt precursor and an aqueous extract of Nephrolepis exaltata (N. exaltata), which act as a capping and reducing agent. N. exaltata plant extract-mediated ZnO-NPs were further characterized by various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), UV-visible (UV-Vis), and energy-dispersive X-ray (EDX) analysis. The nanoscale crystalline phase of ZnO-NPs was analyzed by the XRD patterns. The FT-IR analysis revealed different functional groups of biomolecules involved in the reduction and stabilization of the ZnO-NPs. The light absorption and optical properties of ZnO-NPs were examined by UV-Vis spectroscopy at a wavelength of 380 nm. The spherical shape morphology of ZnO-NPs with mean particle size ranges between 60 and 80 nm was confirmed by SEM images. While the EDX analysis was used to identify the elemental composition of ZnO-NPs. Furthermore, the synthesized ZnO-NPs demonstrate potential antiplatelet activity by inhibiting the platelet aggregation induced by platelet activation factor (PAF) and arachidonic acid (AA). The results showed that synthesized ZnO-NPs were more effective in inhibiting platelet aggregation induced by AA with IC50 (56% and 10 µg/mL) and PAF (63% and 10 µg/mL), respectively. However, the biocompatibility of ZnO-NPs was assessed in human lung cancer cell line (A549) under in vitro conditions. The cytotoxicity of synthesized nanoparticles revealed that cell viability decreased and the IC50 was found to be 46.7% at a concentration of 75 µg/mL. The present work concluded the green synthesis of ZnO-NPs that was achieved by N. exaltata plant extract and showed good antiplatelet and cytotoxic activity, which demonstrates the lack of harmful effects making them more effective for use in pharmaceutical and medical fields to treat thrombotic disorders.

Contrasting effects of nitrogen and phosphorus additions on nitrogen competition between coniferous and broadleaf seedlings.

Nitrogen (N) is a major element limiting plant growth and metabolism. Nitrogen addition can influence plant growth, N uptake, and species interactions, while phosphorus (P) addition may affect N acquisition. However, knowledge of how nutrient availability influences N uptake and species interactions remains limited and controversial. Here, pot experiments were conducted for 14 months, in which conifers (Pinus massoniana and Pinus elliottii) and broadleaved trees (Michelia maudiae and Schima superba) were planted in monoculture or mixture, and provided additional N and P in a full-factorial design. Nitrogen addition increased the biomass, but P addition did not significantly affect the biomass of the four subtropical species. Combined N and P (NP) addition had no additive effect on plant biomass over N addition. Total plant biomass was significantly positively correlated to root traits (branching intensity and root tissue density) and leaf traits (net photosynthetic rate, stomatal conductance, and transpiration rate), but negatively correlated to root diameter in response to nutrient addition. Plant uptake rates of NH4+ or NO3- were not altered by N addition, but P or NP additions decreased NH4+ uptake rates and increased NO3- uptake rates. Neighboring conifers significantly inhibited NH4+ and NO3- uptake rates of the two broadleaf species, but neighboring broadleaves had no effects on the N uptake rates of pine species. The effects of nutrient additions on interspecific interactions differed among species. Nitrogen addition altered the interaction of P. elliottii and M. maudiae from neutral to competition, while P addition altered the interaction of P. massoniana and M. maudiae from neutral to favorable effects. Increasing nutrient availability switched the direction of interspecific interaction in favor of pines. This study provides insights into forest management for productivity improvement and optimizing the selection of broadleaf species regarding differences in soil fertility of subtropical plantations.

Cyclosorus terminans Extract Ameliorates Insulin Resistance and Non-Alcoholic Fatty Liver Disease (NAFLD) in High-Fat Diet (HFD)-Induced Obese Rats.

Interruptins A and B exhibited anti-diabetic, anti-inflammatory, and anti-oxidative effects. This study aimed to investigate the therapeutic ability of extract enriched by interruptins A and B (EEI) from an edible fern Cyclosorus terminans on insulin resistance and non-alcoholic fatty liver disease (NAFLD) in a high-fat diet (HFD)-induced obese rats and elucidate their possible mechanisms. HFD-induced obese rats were treated with EEI for 2 weeks. Real-time polymerase chain reaction (PCR) was used to examine the molecular basis. We found that EEI supplementation significantly attenuated body and liver weight gain, glucose intolerance, and insulin resistance. Concurrently, EEI increased liver and soleus muscle glycogen storage and serum high-density lipoprotein (HDL) levels. EEI also attenuated NAFLD, as indicated by improving liver function. These effects were associated with enhanced expression of insulin signaling genes (Slc2a2, Slc2a4, Irs1 and Irs2) along with diminished expression of inflammatory genes (Il6 and Tnf). Furthermore, EEI led to the suppression of lipogenesis genes, Srebf1 and Fasn, together with an increase in fatty acid oxidation genes, Ppara and Cpt2, in the liver. These findings suggest that EEI could ameliorate HFD-induced insulin resistance and NAFLD via improving insulin signaling pathways, inflammatory response, lipogenesis, and fatty acid oxidation.

Conifer Essential Oils Reversed Amyloid Beta1-42 Action by Modulating BDNF and ARC Expression in The Rat Hippocampus.

BACKGROUND: The conifer species Pinus halepensis (Pinaceae) and Tetraclinis articulata (Cupressaceae) are widely used in traditional medicine due to their beneficial health properties. OBJECTIVE: This study aimed to investigate the mechanisms by which P. halepensis and T. articulata essential oils (1% and 3%) could exhibit neuroprotective effects in an Alzheimer's disease (AD) rat model, induced by intracerebroventricular (i.c.v.) administration of amyloid beta1-42 (Aß1-42). METHODS: The essential oils were administered by inhalation to the AD rat model, once daily, for 21 days. DNA fragmentation was assessed through a Cell Death Detection ELISA kit. Brainderived neurotrophic factor (BDNF), activity-regulated cytoskeleton-associated protein (ARC), and interleukin-1ß (IL-1ß) gene expressions were determined by RT-qPCR analysis, while BDNF and ARC protein expressions were assessed using immunohistochemistry technique. RESULTS: Our data showed that both essential oils substantially attenuated memory impairments, with P. halepensis mainly stimulating ARC expression and T. articulata mostly enhancing BDNF expression. Also, the inhalation of essential oils reduced IL-1ß expression and induced positive effects against DNA fragmentation associated with Aß1-42-induced toxicity, further contributing to the cognitive improvement in the rats with the AD-like model Conclusion: Our findings provide further evidence that these essential oils and their chemical constituents could be natural agents of therapeutic interest against Aß1-42-induced neurotoxicity.

The effect of polysaccharides from Cibotium barometz on enhancing temozolomide-induced glutathione exhausted in human glioblastoma U87 cells, as revealed by 1H NMR metabolomics analysis.

Glioblastoma (GBM) is the most malignant central nervous system tumor, with poor prognosis. Temozolomide (TMZ) has been used as a first-line drug for the treatment of GBM for over a decade, but its treatment benefits are limited by acquired resistance. Polysaccharides from Cibotium barometz (CBPs) are polysaccharides purified from the root of Cibotium barometz (L.) J. Sm., possessing sensitizing activity. The purpose of this study was to investigate the anti-cancer effect of CBP from different processing methods on U87 cells using a 1H NMR-based metabolic approach, complemented with qRT-PCR and flow cytometry, to identify potential markers and discover the targets to explore the underlying mechanism. Cibotium barometz is usually processed under sand heating in clinical applications. Polysaccharides from both the processed (PCBP) and raw (RCBP) C. barometz were prepared, and the effect on enhancing the sensitivity to TMZ was investigated in vitro. CBP can significantly increase the toxicity of TMZ to the U87 cell line, promote apoptosis, enhance cell cycle changes, and arrest cells in S phase, and RCBP demonstrated better activity. Multivariate statistical analyses, such as principal component analysis (PCA) and orthogonal projection to latent structure with discriminant analysis (OPLS-DA), were used to identify metabolic biomarkers, and 12 metabolites in the cell extract samples were clearly identified as altered after RCBP exposure. NMR-based cell metabolomics provided a holistic method for the identification of CBP's apoptosis-enhancing mechanisms and the exploration of its potential applications in preclinical and clinical studies.

Experimental studies on high-quality bio-oil production via pyrolysis of Azolla by the use of a three metallic/modified pyrochar catalyst.

In this study, the potential of the pyrolysis method to overcome the negative effects of Azolla-filiculoides in infected areas was thoroughly investigated. Non-catalytic pyrolysis experiments were conducted at a temperature range of 400-700 °C. The highest possible bio-oil yield (35 wt%) was attained at 500 °C. To achieve the best chemical composition of bio-oil and higher amount of synthesis gas the catalytic pyrolysis were conducted in a dual-bed quartz reactor at the optimum temperature (500 °C). Although, all three catalysts (pyro-char, modified pyro-char (MPC), and Mg-Ni-Mo/MPC) showed almost an impressive performance in promotion of the common reactions, Mg-Ni-Mo/MPC catalyst have illustrated the stunning results by increasing the percentage of furan compounds from 5.25% to 33.07%, and decreasing the acid compounds from 25.56% to 9.09%. Using GC-MS and GC-FID liquid and gaseous products were fully analyzed. The carbon-based catalysts were also evaluated via FTIR, FESEM, EDX, and BET analyses.

High nitrogen contribution by Gunnera magellanica and nitrogen transfer by mycorrhizas drive an extraordinarily fast primary succession in sub-Antarctic Chile.

Chronosequences at the forefront of retreating glaciers provide information about colonization rates of bare surfaces. In the northern hemisphere, forest development can take centuries, with rates often limited by low nutrient availability. By contrast, in front of the retreating Pia Glacier (Tierra del Fuego, Chile), a Nothofagus forest is in place after only 34 yr of development, while total soil nitrogen (N) increased from near zero to 1.5%, suggesting a strong input of this nutrient. We measured N-fixation rates, carbon fluxes, leaf N and phosphorus contents and leaf δ15 N in the dominant plants, including the herb Gunnera magellanica, which is endosymbiotically associated with a cyanobacterium, in order to investigate the role of N-fixing and mycorrhizal symbionts in N-budgets during successional transition. G. magellanica presented some of the highest nitrogenase activities yet reported (potential maximal contribution of 300 kg N ha-1  yr-1 ). Foliar δ15 N results support the framework of a highly efficient N-uptake and transfer system based on mycorrhizas, with c. 80% of N taken up by the mycorrhizas potentially transferred to the host plant. Our results suggest the symbiosis of G. magellanica with cyanobacteria, and trees and shrubs with mycorrhizas, to be the key processes driving this rapid succession.

Accumulation of uranium and heavy metals in the soil-plant system in Xiazhuang uranium ore field, Guangdong Province, China.

Plants that have grown for many years in the special environmental conditions prevailing in mining areas are naturally screened and show strong capacity to adapt to their environment. The present study investigated the enrichment characteristics of U and other heavy metals (As, Cu, Pb, Mn, Mo, Zn, Cd, Co, and Ni) in the soil-plant system in Xiazhuang uranium mine. Four dominant plants (Castanopsis carlesii, Rhus chinensis, Liriodendron chinense, and Sapium discolor) and soil samples were collected from the mined areas, unmined areas, and background areas away from the ore field. U, As, Cu, Pb, Mn, Mo, Zn, Cd, Co, and Ni concentrations were analyzed by ICP-MS. The results demonstrate that (1) The highest concentrations of U (4.1-206.9 mg/kg) and Pb (43.3-126.0 mg/kg) with the geoaccumulation index (Igeo) greater than 1 show that they are the main soil pollutants in the research area. (2) The biological accumulation coefficient (LBAC) values for Cd, Mn, and Cu are greater than zero in S. discolor, L. chinense, and C. carlesii and these three plants indicate that they can be used for remediation of the soil in the ore field. (3) R. chinensis inhibits the accumulation of heavy metals and shows sensitive pigment responses to the accumulation of U in the leaves. L. chinense has the strongest enrichment effect on heavy metals but exhibits weak biochemical responses under U stress. C. carlesii demonstrates strong adaptation to U and can maintain healthy pigment characteristics in case of high U enrichment. (4) S. discolor, L. chinense, C. carlesii and R. chinensis have strong tolerance to U toxicity and different biochemical responses.

Functions of stone cells and oleoresin terpenes in the conifer defense syndrome.

Conifers depend on complex defense systems against herbivores. Stone cells (SC) and oleoresin are physical and chemical defenses of Sitka spruce that have been separately studied in previous work. Weevil oviposit at the tip of the previous year's apical shoot (PYAS). We investigated interactions between weevil larvae and trees in controlled oviposition experiments with resistant (R) and susceptible (S) Sitka spruce. R trees have an abundance of SC in the PYAS cortex. SC are mostly absent in S trees. R trees and S trees also differ in the composition of oleoresin terpenes. Transcriptomes of R and S trees revealed differences in long-term weevil-induced responses. Performance of larvae was significantly reduced on R trees compared with S trees under experimental conditions that mimicked natural oviposition behavior at apical shoot tips and may be attributed to the effects of SC. In oviposition experiments designed for larvae to feed below the area of highest SC abundance, larvae showed an unusual feeding behavior and oleoresin appeared to function as the major defense. The results support a role for both SC and oleoresin terpenes and possible synergies between these traits in the defense syndrome of weevil-resistant Sitka spruce.

Responses to competition for nitrogen between subtropical native tree seedlings and exotic grasses are species-specific and mediated by soil N availability.

Competitive interactions between native tree seedlings and exotic grasses frequently hinder forest restoration. We investigated the consequences of competition with exotic grasses on the growth and net nitrogen (N) uptake capacity of native rainforest seedlings used for reforestation depending on soil N availability and N source. Tree seedlings and grasses were grown in the greenhouse in different competition regimes (one tree species vs one grass species) and controls (grass monocultures or single tree seedlings) at low and high soil N. After 8 weeks, we quantified net N uptake capacity using 15N-labelled organic (i.e., glutamine and arginine) and inorganic (i.e., ammonium and nitrate) N sources and biomass indices. Depending on soil N availability, we observed different species-specific responses to growth and N acquisition. Tree seedlings generally increased their net N uptake capacity in response to competition with grasses, although overall seedling growth was unaffected. In contrast, the responses to competition by the grasses were species-specific and varied with soil N availability. The different N acquisition strategies suggest the avoidance of competition for N between trees and grasses. Overall, the results highlight that quantifying underlying mechanisms of N acquisition complements the information on biomass allocation as a measure of responses to competition, particularly with varying environmental conditions.

Nutrient release and uptake by littoral macrophytes during water level fluctuations.

Water level drawdown followed by rewetting in reservoirs/lakes can shift macrophytes from a nutrient sink to a source, thus changing nutrient dynamics and causing water quality problems. However, there is limited understanding of the effect of macrophyte growth versus decomposition on nitrogen (N) and phosphorus (P) dynamics during water level fluctuations (WLFs). This study examined nutrient release versus uptake by two submerged macrophytes, the invasive Cabomba caroliniana (Cabomba) and the native Hydrilla verticillata (Hydrilla), compared to bare sediments, after drying then rewetting. Overall, we examined the nutrient dynamics in treatments comparing 1) two macrophyte species, 2) macrophyte nutrient uptake versus release, and 3) the presence of macrophytes versus bare sediments. Our study showed that Cabomba litter had a higher nutrient release rate and resulted in higher water column chlorophyll a concentrations compared with Hydrilla litter. The decomposition impact of both species on water column P concentrations was greater than that for N, and proportionally less P was assimilated than released by macrophytes compared with N. This resulted in P accumulation and a decreased N:P ratio in the water column compared to bare sediments without macrophytes. Phosphorus accumulation in the water column during macrophyte decomposition increased phytoplankton growth in our study, highlighting the potential for phytoplankton blooms, especially in P-deficient lakes. Regrown Hydrilla had a higher potential for assimilating sediment N compared to Cabomba. In contrast, regrown Cabomba was more efficient at reducing water column N compared with Hydrilla, suggesting different pathways of assimilation. Neither regrown Cabomba nor Hydrilla significantly reduced water column P concentrations. This study highlights different nutrient impacts of macrophyte beds compared to bare sediments during WLFs, and the role of regrown macrophytes in assimilating the released nutrients from macrophyte decomposition. However, the scale of their role is dependent on macrophyte species, forms of nutrients and drying-wetting regimes.

The evolution of aluminum accumulation in ferns and lycophytes.

PREMISE OF THE STUDY: This paper investigates the occurrence and evolution of aluminum (Al) accumulation within ferns and lycophytes, which is characterized by Al concentrations above 1000 mg·kg-1 in aboveground plant tissues. We hypothesize that this feature is more common in ferns than in angiosperms, and potentially correlated with growth form and other chemical elements. METHODS: Aluminum concentrations were obtained from novel analyses and literature for a total of 354 specimens and 307 species. Moreover, a semiquantitative aluminon test was applied for a subset of 105 species and validated against exact Al measurements. KEY RESULTS: Molecular phylogenetic analyses showed that the major Al-accumulating groups were primarily found in the Gleicheniales and Cyatheales, and largely absent in the Polypodiales. At the species and generic level, Al accumulation was typically either absent or present, and mixed results within a single species and genus were limited to less than 30% of the species and genera tested. Epiphytic ferns had significantly lower Al levels than terrestrial ferns, although this finding was not significant after phylogenetic correction. In addition, a significant, positive correlation was found between Al and iron, while Al was negatively correlated with phosphorus and potassium concentrations. CONCLUSIONS: Aluminum accumulation is most common outside of the Polypodiales and occurs in 38% of the species studied, indicating that this trait is indeed common within subtropical and tropical ferns, a finding that could be in line with their role as pioneer species on landslides and soils with high levels of soluble Al.

Effectiveness of Vegetated Drainage Ditches for Domestic Sewage Effluent Mitigation.

Plant species have an important role in eco-ditches; however, the Michaelis-Menten kinetic parameters of nutrient uptake, growth rate and purification efficiency of ditch plants and their influences on domestic sewage treatment efficiency are still unclear. Growth rates of all nine species, but especially Lemna gibba, Cladophora and Myriophyllum verticillatum were best in undiluted domestic sewage as opposed to a mixture of domestic sewage. Performance of species to accumulate nutrients was not only species-specific, but was also affected by both sewage treatments. Removal efficiency of nutrients was dependent on both plant species and treatment. Uptake kinetic parameters were significantly affected by both nutrient form and plant species. The maximum uptake rate (Vmax) of NH4-N was higher than NO3-N. Similarly, Km values for NH4-N were greater than NO3-N. These results could be used to identify plants for sewage treatment efficiency and enhance water quality in eco-ditch treatment systems.

Comparison of Chemical Compositions in Pseudostellariae Radix from Different Cultivated Fields and Germplasms by NMR-Based Metabolomics.

Pseudostellariae Radix (PR) is an important traditional Chinese medicine (TCM), which is consumed commonly for its positive health effects. However, the chemical differences of PR from different cultivated fields and germplasms are still unknown. In order to comprehensively compare the chemical compositions of PR from different cultivated fields, in this study, ¹H-NMR-based metabolomics coupled with high performance liquid chromatography (HPLC) were used to investigate the different metabolites in PR from five germplasms (jr, zs1, zs2, sb, and xc) cultivated in traditional fields (Jurong, Jiangsu, JSJR) and cultivated fields (Zherong, Fujian, FJZR). A total of 34 metabolites were identified based on ¹H-NMR data, and fourteen of them were found to be different in PR from JSJR and FJZR. The relative contents of alanine, lactate, lysine, taurine, sucrose, tyrosine, linolenic acid, γ-aminobutyrate, and hyperoside in PR from JSJR were higher than that in PR from FJZR, while PR from FJZR contained higher levels of glutamine, raffinose, xylose, unsaturated fatty acid, and formic acid. The contents of Heterophyllin A and Heterophyllin B were higher in PR from FJZR. This study will provide the basic information for exploring the influence law of ecological environment and germplasm genetic variation on metabolite biosynthesis of PR and its quality formation mechanism.

A stepwise protocol for induction and selection of prominent coniferous cell cultures for the production of ß-thujaplicin.

In order to demonstrate the potential of plant cell culture systems to produce a target natural bioactive compound, we proposed a stepwise protocol for ß-thujaplicin production as follows. 1. Induction phase: Characteristics of callus cultures originating from newly flushed shoots of 10 conifer species were evaluated on different basal media such as Murashige and Skoog (MS), Schenk and Hildebrandt (SH), and Lloyd and McCown's Woody Plant medium (WP) containing 10 µM 2,4-dichlorophenoxyacetic acid (2,4-D) either alone or in combination with 1 µM of N6-benzyladenine (BA). The conifer species used were as follows: Chamaecyparis (C. obtusa Sieb. et Zucc. and C. pisifera Sieb. et Zucc.), Juniperus (J. chinensis L. 'Kaizuka', J. chinensis L. var. sargentii, and J. conferta Parlatore), Thuja (T. occidentalis L. and T. standishii (Gord.) Carr.), Thujopsis (T. dolabrata Sieb. et Zucc. and T. dolabrata Sieb. et Zucc. var. hondae), and Cryptomeria (C. japonica D. Don). We observed the phenotypes of each callus to determine the optimal conditions for callus induction and to infer biosynthetic activity of the calli over 4-8 weeks. 2. Habituation phase: Each of the cell cultures obtained was transferred to a modified MS medium containing 680 mg L(-1) KH2PO4 and 10 µM Picloram to select the habituated cells with synchronous growth pattern. The growth of each cell culture was highly improved in the habituation medium, except that of J. chinensis 'Kaizuka'. 3. Metabolite-production phase: The concentration of ß-thujaplicin (known as hinokitiol in Japan) in the shoots of donor trees and the habituated cell cultures was analyzed via high-performance liquid chromatography (HPLC). Histochemical characteristics of the cells were also observed using laser scanning microscopy (LSM) imaging. After the third step, we tested the biosynthetic activity of two habituated calli (C. obtusa and J. conferta) on a 0.3%, w/v, yeast extract (YE)-containing medium. We found significant improvement in ß-thujaplicin production in J. conferta callus (4600 µg g DW-1), which was up to 20-fold higher than in the habituation phase.

Exploring continental-scale stand health - N : P ratio relationships for European forests.

Understanding the relationship between nitrogen (N) availability and stand health in forest ecosystems is crucial, because a large proportion of European forests is subjected to N-deposition levels beyond their retention capacity. We used data from a long-term forest monitoring programme (ICP Forests) to test the relationship between an index of N availability, foliar nitrogen : phosphorus (N : P) ratios, tree defoliation and discoloration. We hypothesized a segmented response of stand health to N : P ratios and an improved model-fit after correcting for climatic covariates. In accordance with the hypothesis, we found a segmented response with a breakpoint for conifer defoliation at N : P ratios as low as 7.3. Inclusion of climatic variables improved the fit of the models, but there was significant collinearity with N : P. Increases in N availability appear, at least for conifers, to have a negative effect on tree health even under N-limiting conditions. Regulation of N-deposition levels is consequently as timely as ever. We propose that increases in tree defoliation, other than resulting in serious plant fitness issues, may represent early diagnostic symptoms of N-addition related imbalances.

Cytotoxic compounds from invasive giant salvinia (Salvinia molesta) against human tumor cells.

Giant salvinia (Salvinia molesta) is one of the most noxious invasive species in the world. Our bioactivity-guided fractionation of ethanol extract of giant salvinia led to the isolation of 50 compounds. Of the six new compounds (1-6), salviniol (1) is a rare abietane diterpene with a new ferruginol-menthol coupled skeleton and both salviniside I (2) and salviniside II (3) are novel benzofuran glucose conjugates with unique 10-membered macrodiolide structures. Sixteen abietane diterpenes (1, 7-17, and 19-22) demonstrated in vitro activities against human tumor cells, and 7 and 8 showed selective cytotoxicity to tumor cells over normal cells.

Arginine, scurvy and Cartier's "tree of life".

Several conifers have been considered as candidates for "Annedda", which was the source for a miraculous cure for scurvy in Jacques Cartier's critically ill crew in 1536. Vitamin C was responsible for the cure of scurvy and was obtained as an Iroquois decoction from the bark and leaves from this "tree of life", now commonly referred to as arborvitae. Based on seasonal and diurnal amino acid analyses of candidate "trees of life", high levels of arginine, proline, and guanidino compounds were also probably present in decoctions prepared in the severe winter. The semi-essential arginine, proline and all the essential amino acids, would have provided additional nutritional benefits for the rapid recovery from scurvy by vitamin C when food supply was limited. The value of arginine, especially in the recovery of the critically ill sailors, is postulated as a source of nitric oxide, and the arginine-derived guanidino compounds as controlling factors for the activities of different nitric oxide synthases. This review provides further insights into the use of the candidate "trees of life" by indigenous peoples in eastern Canada. It raises hypotheses on the nutritional and synergistic roles of arginine, its metabolites, and other biofactors complementing the role of vitamin C especially in treating Cartier's critically ill sailors.

The effect of polyethylene glycol on intake of Mediterranean shrubs by sheep and goats.

Poor nutritional quality and increased content of secondary compounds can reduce consumption of Mediterranean shrubs by herbivores. In 2 sequential trials, we examined the effect of polyethylene glycol (PEG) and number of shrub species offered on daily intake of Mediterranean shrubs by 12 sheep and 12 goats. The PEG (25 g) was fed to experimental animals with barley. In trial 1 (6 shrubs), goats ate more (P = 0.0008) daily total shrub biomass than did sheep (60.7 vs. 45.9 +/- 2.6 g/kg of BW). There was a trend (P = 0.08) toward a positive PEG effect on total shrub intake, with PEG-supplemented animals consuming more total shrubs than controls (56.7 vs. 50.0 +/- 2.6 g/kg of BW). Trial 2 (using 3 shrubs) was a continuation of trial 1, except that animals were given less barley and treatment animals were given more PEG (50 g). Both sheep and goats showed a numerical decrease in total shrub intake from trial 1 to trial 2. Sheep receiving PEG ate more (P = 0.002) total shrubs than did controls, but no PEG effect was found for goats. Thus, PEG had a greater influence on sheep than goats when only 3 shrubs were offered, a result that may be related to the fact that fewer shrubs with complementary secondary compounds were offered and that goats appear to have a greater ability to consume and detoxify secondary compounds from Mediterranean shrubs. Overall, as the number and diversity of shrubs offered increased, supplemental PEG had less effect on increasing intake for both goats and sheep.