Meng-Yuan Huang

Antioxidant activity of herbaceous plant extracts protect against hydrogenperoxide-induced DNA damage in human lymphocytes

BackgroundHerbaceous plants containing antioxidants can protect against DNA damage. Thepurpose of this study was to evaluate the antioxidant substances,antioxidant activity, and protection of DNA from oxidative damage in humanlymphocytes induced by hydrogen peroxide (H2O2). Ourmethods used acidic methanol and water extractions from six herbaceousplants, including Bidens alba (BA), Lycium chinense (LC),Mentha arvensis (MA), Plantago asiatica (PA),Houttuynia cordata (HC), and Centella asiatica(CA).MethodsAntioxidant compounds such as flavonol and polyphenol were analyzed.Antioxidant activity was determined by the inhibition percentage ofconjugated diene formation in a linoleic acid emulsion system and bytrolox-equivalent antioxidant capacity (TEAC) assay. Their antioxidativecapacities for protecting human lymphocyte DNA fromH2O2-induced strand breaks was evaluated by cometassay.ResultsThe studied plants were found to be rich in flavonols, especially myricetinin BA, morin in MA, quercetin in HC, and kaemperol in CA. In addition,polyphenol abounded in BA and CA. The best conjugated diene formationinhibition percentage was found in the acidic methanolic extract of PA.Regarding TEAC, the best antioxidant activity was generated from the acidicmethanolic extract of HC. Water and acidic methanolic extracts of MA and HCboth had better inhibition percentages of tail DNA% and tail moment ascompared to the rest of the tested extracts, and significantly suppressedoxidative damage to lymphocyte DNA.ConclusionQuercetin and morin are important for preventing peroxidation and oxidativedamage to DNA, and the leaves of MA and HC extracts may have excellentpotential as functional ingredients representing potential sources ofnatural antioxidants.

Life time deficiency of photosynthetic pigment-protein complexes CP1, A1, AB1, and AB2 in two cecidomyiid galls derived from Machilus thunbergii leaves

Two kinds of cecidomyiid galls induced by Daphnephila on Machilus thunbergii Sieb. & Zucc. leaves at various developmental stages, i.e., young, growing, and mature, were analyzed for their biochemical composition of photosynthetic pigment-protein complexes located in thylakoid membranes using the Thornber and MARS electrophoretic fractionation systems. Both kinds of galls were totally deficient in the pigment-protein complexes CP1, and A1, AB1, and AB2 through the whole period of gall formation. Immunoblotting of antibody against light-harvesting complex 2b (LHC2b) apoprotein confirmed this deficiency in gall’s lifetime, which never recovered under any condition. Electron microscopy demonstrated that already at the early developmental stage the gall chloroplasts had thylakoid morphology like that in a normal leaf.

Inhibitive Effects of Mulberry Leaf-Related Extracts on Cell Adhesion and Inflammatory Response in Human Aortic Endothelial Cells

Effects of mulberry leaf-related extracts (MLREs) on hydrogen peroxide-induced DNA damage in human lymphocytes and on inflammatory signaling pathways in human aortic endothelial cells (HAECs) were studied. The tested MLREs were rich in flavonols, especially bombyx faces tea (BT) in quercetin and kaempferol. Polyphenols, flavonoids, and anthocyanidin also abounded in BT. The best trolox equivalent antioxidant capacity (TEAC) was generated from the acidic methanolic extracts of BT. Acidic methanolic and water extracts of mulberry leaf tea (MT), mulberry leaf (M), and BT significantly inhibited DNA oxidative damage to lymphocytes based on the comet assay as compared to the H2O2-treated group. TNF-α-induced monocyte-endothelial cell adhesion was significantly suppressed by MLREs. Additionally, nuclear factor kappa B (NF-κB) expression was significantly reduced by BT and MT. Significant reductions were also observed in both NF-κB and activator protein (AP)-1 DNA binding by MLREs. Significant increases in peroxisome proliferator-activated receptor (PPAR) α and γ DNA binding by MLREs were also detected in M and MT extracts, but no evidence for PPAR α DNA binding in 50 μg/mL MT extract was found. Apparently, MLREs can provide distinct cytoprotective mechanisms that may contribute to its putative beneficial effects on suppressing endothelial responses to cytokines during inflammation.

Photosynthetic responses of Jatropha curcas to spider mite injury

The spider mite Tetranychus urticae Koch is emerging as a major problem in Jatropha curcas cultivation. The goal of this study was to investigate the photosynthetic responses of Jatropha to spider mite infestation. Leaf CO2 assimilation rate, stomatal conductance, transpiration, intracellular CO2 concentration, and instantaneous carboxylation efficiency significantly decreased in mite-infested leaves compared with controls. Lower water content and specific leaf area of the mite-infested leaves were positively related to symptoms of wrinkling and curling. Leaf electrolyte leakage remained unchanged in the mite-infested leaves, revealing no effect on leaf membrane integrity. Leaves exhibited reductions in soluble protein and soluble sugar in association with photosynthetic impairment. Although decreases in photochemical activity and chlorophyll fluorescence parameters suggested damage to the photosynthetic apparatus, although there were no measurable reductions in chlorophyll or carotenoid contents associated with photosynthetic apparatus impairment. The decrease in the leaf CO2 assimilation rate was partially attributed to stomatal and metabolic limitations in the mite-infested leaves.

Light induction of nonphotochemical quenching, CO2 fixation, and photoinhibition in woody and fern species adapted to different light regimes

We aimed to find out relations among nonphotochemical quenching (NPQ), gross photosynthetic rate (PG), and photoinhibition during photosynthetic light induction in three woody species (one pioneer tree and two understory shrubs) and four ferns adapted to different light regimes. Pot-grown plants received 100% and/or 10% sunlight according to their light-adaptation capabilities. After at least four months of light acclimation, CO2 exchange and chlorophyll fluorescence were measured simultaneously in the laboratory. We found that during light induction the formation and relaxation of the transient NPQ was closely related to light intensity, light-adaption capability of species, and PG. NPQ with all treatments increased rapidly within the first 1–2 min of the light induction. Thereafter, only species with high PG and electron transport rate (ETR), i.e., one pioneer tree and one mild shade-adapted fern, showed NPQ relaxing rapidly to a low steady-state level within 6–8 min under PPFD of 100 μmol(photon) m−2 s−1 and ambient CO2 concentration. Leaves with low PGand ETR, regardless of species characteristics or inhibition by low CO2 concentration, showed slow or none NPQ relaxation up to 20 min after the start of low light induction. In contrast, NPQ increased slowly to a steady state (one pioneer tree) or it did not reach the steady state (the others) from 2 to 30 min under PPFD of 2,000 μmol m−2 s−1. Under high excess of light energy, species adapted to or plants acclimated to high light exhibited high NPQ at the initial 1 or 2 min, and showed low photoinhibition after 30 min of light induction. The value of fastest-developing NPQ can be quickly and easily obtained and might be useful for physiological studies.

Transcriptome profile of cup-shaped galls in Litsea acuminata leaves

Background Insect galls are atypical plant tissues induced by the invasion of insects. Compared to the host leaf, gall tissues lose photosynthetic ability, but have higher soluble sugar content. Although the physiological and biochemical regulation of gall tissues have been demonstrated, the mechanism of genetic regulation has only been analyzed in few studies. Results In this study, the transcriptome of cup-shaped galls and its host leaf were de novo assembled. Cellular functional enrichment and differentially expressed gene groups in the gall tissues were analyzed. The genes associated with primary metabolism, including photosynthesis, cell wall turnover, and sugar degradation, were expressed differently in galls and leaves. The examination of gene expression demonstrated that the genes involved in brassinosteroid synthesis and responses exhibited a remarkable modulation in cup-shaped galls, suggesting a potential role of steroid hormones in regulating gall development. Conclusions This study revealed the genetic responses, including those involved in source-sink reallocation and phytohormone metabolism, of galls induced by a dipteran insect.

Eliminating interference by anthocyanins when determining the porphyrin ratio of red plant leaves

Anthocyanins (Ants) are water-soluble secondary metabolites that are responsible for red colour of plant leaves. To determine photosynthetic pigments, 80% acetone was used to extract Ants from Ant-containing leaves of test plants. However, using the 80% acetone extraction method can lead to interference between chlorophylls (Chls) and Ants. Porphyrins, such as protoporphyrin IX (PPIX), Mg-protoporphyrin IX (MgPP), and protochlorophyllide (Pchlide), are Chl biosynthetic intermediates and demonstrate photospectrometric characteristics similar to those of Chl. Although the ether/water extraction method was able to remove Ants interference when detecting porphyrins, the porphyrins extraction efficiency was lower than that of the 80% acetone extraction method. Low Ants levels interfered with individual porphyrin ratios, and the extent of the effect was correlated with Ants concentrations. We developed the three equations could eliminate interference by Ants when determining the porphyrin molecular percentage (%) and were comprehensively applied to all tested species of Ants-containing leaves.

Biochemical and Physiological Characteristics of Photosynthesis in Plants of Two Calathea Species

Plants of the genus Calathea possess many leaf colors, and they are economically important because they are widely used as ornamentals for interior landscaping. Physiological performances and photosynthetic capacities of C. insignis and C. makoyana were investigated. The photosynthetic efficiencies of C. insignis and C. makoyana were significantly increased when the photosynthetic photon flux density (PPFD) increased from 0 to 600 μmol photons·m−2·s−1 and became saturated with a further increase in the PPFD. The two Calathea species had lower values of both the light saturation point and maximal photosynthetic rate, which indicated that they are shade plants. No significant differences in predawn Fv/Fm values (close to 0.8) were observed between dark-green (DG) and light-green (LG) leaf sectors in all tested leaves. However, the effective quantum yield of photosystem II largely decreased as the PPFD increased. An increase in the apparent photosynthetic electron transport rate was observed in both species to a maximum at 600 μmol·m−2·s−1 PPFD, following by a decrease to 1500 μmol·m−2·s−1 PPFD. Compared to LG leaf extracts, DG leaf extracts contained higher levels of chlorophyll (Chl) a, Chl b, Chls a + b, carotenoids (Cars), anthocyanins (Ants), flavonoids (Flas), and polyphenols (PPs) in all plants, except for the Ant, Fla and PP contents of C. insignis plants. Calathea insignis also contained significantly higher levels of total protein than did C. makoyana. The adjusted normalized difference vegetation index (NDVI), photochemical reflectance index (PRI), red-green, and flavonol index (FlavI) were significantly correlated to leaf Chls a + b, Cars, Ants, and Flas in C. makoyana, respectively, and can be used as indicators to characterize the physiology of these plants.

Grey relational analysis between agronomic characters and maturity of sugarcane

This study applied grey system theory to analyze the relationship between eight agronomic characters including plant height, leaf fresh weight, leaf dry weight, leaf water content, internodes number of dead-leaf stalk, internodes number of green-leaf stalk, juice brix of dead-leaf stalk and juice brix of green-leaf stalk, and the maturity of sugarcane. The contribution degrees of agronomic characters, indicated by grey order, to maturity of sugarcane were: juice brix of green-leaf stalk＞leaf dry weight＞juice brix of dead-leaf stalk＞plant height＞internodes number of green-leaf stalk＞leaf fresh weight＞leaf water content＞internodes number of dead-leaf stalk. Therefore, the juice brix of green-leaf stalk and dead-leaf stalk, leaf dry weight and plant height were the most critical characters to the maturity of sugarcane. The result based on grey relational analysis might be used as a valuable reference on the field management of sugarcane.

Effect of Nutrient on Growth of Dwarf ＂Kandelia Candel＂ (L.) Druce Evaluated by Grey Relational Analysis

Grey relational analysis was employed to study the effect of nitrogen (N) and/or phosphorus (P or NP) nutrients on the growth of dwarf ＂Kandelia candel＂ (L.) Druce in the Chuwei Mangrove Nature Preserve. A field fertilization experiment was designed using ammonium sulfate and superphosphate as the main sources of N and P. Shoots with at least 8 pairs of leaves, of which the two oldest pairs were yellowing, were collected at one year after fertilization. Chlorophyll content of eight proposed stages, including pigment synthesis and degradation, was determined. The primitive sequence data were constructed, and the grey initial normalization and mean normalization were calculated. For chlorophyll content and a/b ratio, the grey relational grade and order, based on both initial and mean normalization, is Γ_P＞Γ_(NP)＞Γ_N, indicating the similarity with non-fertilizer plants is P ＞ NP ＞N. In other words, P treatment affected chlorophyll accumulation and the a/b ratio patterns were less than NP and N treatment. Thus, the order of the factor importance, which is the reverse sequence of the grey relational grade, is N＞NP＞P. The grey relational analysis strongly indicated that N is the most important factor affecting the synthesis and degradation of chlorophyll in dwarf ＂K. candel＂ (L.) Druce; P is not so important as N; however, the combination of N and P had the same effect as N.