Barn swallows Hirundo rustica form eggs mainly from current food intake

Birds might form eggs from stored nutrients, from current food intake or from both. We examined whether stored nutrients were a substantial resource for egg production in an aerial insectivore, which had a variable food supply, but for which there was likely to be a cost for carrying additional mass. The mass changes of female barn swallows Hirundo rustica during the egg formation period were most simply explained by changes in the mass of the eggs and oviduct. Fat score and body mass excluding the eggs and oviduct did not vary systematically during egg formation. Egg production stopped altogether during particularly bad weather. The normal range in environmental conditions before and during laying had little influence on clutch size. Our results suggest that swallows form eggs primarily from current food intake, although our data do not exclude use of micronutrients from reserves.     

THE RELATIONSHIP OF BODY SIZE AND GROWTH TO EGG PRODUCTION IN THE HERMAPHRODITIC FRESHWATER SNAIL, HELISOMA TRIVOLVIS

Among several other factors, body size has been found to influenceegg production in several species of hermaphroditic snail. Wetested whether this relationship between body size and egg productionexists in Helisoma trivolvis, a freshwater hermaphroditic species.We isolated 50 H. trivolvis from a laboratory population, measuredshell diameter, and monitored egg production for seven weeks.We found a positive relationship between body size and totalnumber of eggs produced, as well as body size and number ofeggs per egg mass. When body size and egg production are linked,it should be adaptive for larger individuals to act as femalesand smaller individuals as males. Since body size is relatedto female fecundity in this species, the relative size of snailsshould determine, at least in part, which individual acts asmale and which as female during copulation. However, the relationshipbetween body size and egg production is not nearly as strongas it is in other snail genera. Other factors such as age, genotypeand previous experience may be important in determining egg-layingcapacity and therefore gender choice in this species. In addition,we found a negative relationship between growth during thisperiod and egg production. This relationship has been foundin other pulmonates, and is evidence of resource allocationtradeoffs. (Received 3 August 2004; accepted 2 August 2005)     

Saltwater spray as an agent of natural selection: no evidence of local adaptation within a coastal population of Triplasis purpurea (Poaceae)

An ability to tolerate airborne saltwater spray is critical for plant populations in coastal environments. The opportunity for continued microevolution for improved salt tolerance can exist if there is variation in the response of genetic families to saltwater spray. Our objective was to determine whether or not there was differentiation among subpopulations near (15 m) and far (80 m) from shore and among families within subpopulations in relation to the effects of salt spray on life history traits in a population of the dunegrass Triplasis purpurea. In this annual, most seeds are matured in cleistogamous spikelets on axillary, leaf-sheath enclosed panicles and show poor dispersal capacity. Plants were reared in the greenhouse from seeds of 13 and 11 families from the near and far subpopulations, respectively. Fifty percent of plants in a family were subjected to 6 seawater sprays/wk, resulting in weekly salt deposition of 213 μg/cm(2); the others were sprayed with distilled water. Data were recorded on life span, tiller numbers, root and shoot dry mass, and seed production. There was no effect of subpopulation on any measured trait and, hence, no evidence for local adaptation to salt spray. Final tiller numbers, but not dry mass or seed production, were reduced by salt spray. However, for most traits there were significant family (within subpopulation) effects, indicating genetic substructuring. Life span and mean seed mass showed a significant family by treatment interaction, indicating genetic variation in phenotypic responses to salt spray. Life span and mean seed mass were reduced by salt spray in some, but not all, families. Path analysis revealed that an increase in life span or tiller number indirectly increased seed production via direct effects on vegetative mass. For this relatively salt-tolerant T. purpurea population on the south shore of Staten Island, New York, USA, salt sprays may not be a significant agent of natural selection. However, there are pronounced phenotypic differences among inbred family groups and opportunity for genetic substructuring within these subpopulations. Variable effects of salt spray among families could result in microevolutionary changes in life span and mean seed mass, both of which impact annual fitness in this dunegrass.     

Reproductive output of invasive versus native plants

Aim Propagule size and output are critical for the ability of a plant species to colonize new environments. If invasive species have a greater reproductive output than native species (via more and/or larger seeds), then they will have a greater dispersal and establishment ability. Previous comparisons within plant genera, families or environments have conflicted over the differences in reproductive traits between native and invasive species. We went beyond a genus‐, family‐ or habitat‐specific approach and analysed data for plant reproductive traits from the global literature, to investigate whether: (1) seed mass and production differ between the original and introduced ranges of invasive species; (2) seed mass and production differ between invasives and natives; and (3) invasives produce more seeds per unit seed mass than natives. Location Global. Methods We combined an existing data set of native plant reproductive data with a new data compilation for invasive species. We used t‐tests to compare original and introduced range populations, two‐way ANOVAs to compare natives and invasives, and an ANCOVA to examine the relationship between seed mass and production for natives and invasives. The ANCOVA was performed again incorporating phylogenetically independent contrasts to overcome any phylogenetic bias in the data sets. Results Neither seed mass nor seed production of invasive species differed between their introduced and original ranges. We found no significant difference in seed mass between invasives and natives after growth form had been accounted for. Seed production was greater for invasive species overall and within herb and woody growth forms. For a given seed mass, invasive species produced 6.7‐fold (all species), 6.9‐fold (herbs only) and 26.1‐fold (woody species only) more seeds per individual per year than native species. The phylogenetic ANCOVA verified that this trend did not appear to be influenced by phylogenetic bias within either data set. Main conclusions This study provides the first global examination of both seed mass and production traits in native and invasive species. Invasive species express a strategy of greater seed production both overall and per unit seed mass compared with natives. The consequent increased likelihood of establishment from long‐distance seed dispersal may significantly contribute to the invasiveness of many exotic species.     

Optimization of rhamnetin production in Escherichia coli

POMT7, which is an O-methyltransferase from poplar, transfers a methyl group to several flavonoids that contain a 7-hydroxyl group. POMT7 has been shown to have a higher affinity toward quercetin, and the reaction product rhamnetin has been shown to inhibit the formation of beta-amyloid. Thus, rhamnetin holds great promise for use in therapeutic applications; however, methods for mass production of this compound are not currently available. In this study, quercetin was biotransformed into rhamnetin using Escherichia coli expressing POMT7, with the goal of developing an approach for mass production of rhamnetin. In order to maximize the production of rhamnetin, POMT7 was subcloned into four different E. coli expression vectors, each of which was maintained in E. coli with a different copy number, and the best expression vector was selected. In addition, the S-adenosylmethionine biosynthesis pathway was engineered for optimal cofactor production. Through the combination of optimized POMT7 expression and cofactor production, the production of rhamnetin was increased up to 111 mg/l, which is approximately 2-fold higher compared with the E. coli strain containing only POMT7.     

海藻糖生产菌株筛选过程中产物鉴定的研究

在海藻糖生产菌的筛选过程中,微生物胞内酶转化淀粉生成的产物复杂,将产物逐一纯化是非常烦琐的,但又必须确证产物中是否含有海藻糖。本文将薄层层析、高效液相电喷雾电离质谱联用及核磁共振等分析手段综合应用于海藻糖生产菌株的筛选,在酶反应产物不必被纯化的前提下,准确、快捷地鉴定了酶反应产物中的未知糖组分,最终证明食尼古丁节杆菌（Arthrobacter nicotinovorus）D97利用淀粉或麦芽寡糖的酶反应产物中含有海藻糖。该方法在筛选海藻糖及其它功能性葡二糖生产菌株时较为严密。     

Secondary production of Chironomidae (Diptera) in a north temperate stream

SUMMARY 1. Secondary production of chironomids (Diptera: Chironomidae) in a third-order northern Indiana stream was estimated using species-specific, and in most cases cohort-specific, life-history data from the field.
2. Chironomid life-history patterns were diverse, ranging from one to four generations per year in addition to asynchronous development. Cohort production intervals (CPI) for all taxa ranged from 56 to 266 days. CPI for cohorts of conspecifics differed up to 3-fold.
3. Annual secondary production was estimated using the instantaneous growth method or the size—frequency method depending on whether cohorts were distinguishable or not. Total annual chironomid production was 29 700 mg dry mass m⁻², which is the highest value reported for chironomids from a north temperate stream.
4. Eighty per cent of the total chironomid production was attributed to five species: Diamesa nivoriunda (33.9%), Cricotopus bicinctus (16.6%), Pagastia sp. (10.2%), C. trifascia (9.7%) and Orthodadius obumbratus (9.6%).
5. The annual P:B ratio ranged from 4.7 to 21.9. Thus, high secondary production was due to high mean annual standing stocks and not to rapid biomass turnover.     

Size-Dependent Sex Allocation in Cynoglossum officinale for Different Genotypes Under Uniform Favourable Conditions

Abstract: Field observations showed that small plants often have lower female investment than large plants. Field-collected data do not elucidate, however, whether this pattern is an in herent effect of size or if it is caused by poorer environmental quality of sites where small plants are growing and/or by geno-typic differences between small and large plants. Therefore, the relationship between plant mass and flower and seed pro duction was measured under favourable conditions using full-sibs and clones of Cynogiossum officinale . The aim of this study is to determine if the pattern of size-dependent gender was maintained if both small and large plants are grown under fa vourable conditions, and if this pattern is consistent among genotypes.
Over all genotypes, smaller plants produced more flowers per unit plant mass compared to large plants. On the other hand, seed production per unit plant mass did not significantly differ between plants of different sizes. As a result, the number of seeds per flower increased with increasing plant mass, large plants produced 1.5 times more seeds per flower compared to small plants. Thus small plants emphasize the male side, whereas large plants emphasize the female side of production. We conclude that, even under favourable environmental condi tions, all genotypes examined maintain size-dependent sex allo cation (SDS).
When analysed separately, we found no genetic variation in seed production among genotypes (full sibs and clones). In con trast, genotypes differed significantly in flower production. Nei ther the number of seeds per gram plant mass nor per flower differed significantly among genotypes. In our experiment no evidence was found for a negative genetic correlation between flower production per unit plant mass and seed production per unit plant mass.     

Auxin production by plant-pathogenic pseudomonads and xanthomonads

Pathogenic strains of Xanthomonas campestris pv. glycines which cause hypertrophy of leaf cells of susceptible soybean cultivars and nonpathogenic strains which do not cause hypertrophy were compared for their ability to produce indole compounds, including the plant hormone indole-3-acetic acid (IAA) in liquid media with or without supplementation with l-tryptophan. Several additional strains of plant-pathogenic xanthomonads and pseudomonads were also tested for IAA production to determine whether in vitro production of IAA is related to the ability to induce hypertrophic growth of host tissues. Indoles present in culture filtrates were identified by thin-layer chromatography, high-performance liquid chromatography, UV spectroscopy, mass spectroscopy, and gas chromatography-mass spectrometry and were quantitated by high-performance liquid chromatography. All strains examined produced IAA when liquid media were supplemented with l-tryptophan. The highest levels of IAA were found in culture filtrates from the common bean pathogen Pseudomonas syringae pv. syringae, and this was the only bacterium tested which produced IAA without addition of tryptophan to the medium. Additional indoles identified in culture filtrates of the various strains included indole-3-lactic acid, indole-3-aldehyde, indole-3-acetamide, and N-acetyltryptophan. Pseudomonads and xanthomonads could be distinguished by the presence of N-acetyltryptophan, which was found only in xanthomonad culture filtrates.     

Physiological costs of reproduction in the Sydney rock oyster<Emphasis Type="Italic"> Saccostrea glomerata</Emphasis>

In this study, triploid Sydney rock oysters Saccostrea glomerata, which do not reproduce and have only limited gonadal development, were used to calculate the cost of producing and maintaining somatic tissues. The consumption of oxygen was measured and converted to units of energy expended. The consumption of oxygen of diploid oysters, in different stages of the reproductive cycle, was also measured. Knowing the costs of producing and maintaining somatic tissues (obtained from the triploid oysters), it was possible to calculate the energy demand of somatic and reproductive tissues of diploid oysters. The focus of this study was to test whether this method would work, to investigate if this method would give results in accordance with modern life-history theory and to test hypotheses about costs of reproduction in oysters. It was found that in diploid oysters, 27% of the consumed oxygen was needed for reproductive processes. It was also found that the costs of production and maintenance of reproductive tissues were on average 84% of those of somatic tissues. Costs for the production and maintenance of somatic tissues decreased over time. Costs for reproduction also decreased, but were dependent on the stage of gonadal development. If the relative mass of gametes in the gonads was large, the costs were relatively small; if the mass was relatively small, the costs were large. Differences between traits of males and females were never significant, suggesting that reproductive effort and costs were similar in males and females. It was estimated that if diploid oysters did not reproduce, they could gain 64% more somatic ash-free dry mass. Thus, in terms of growth, reproduction is an expensive activity.     

Body mass–abundance relationships are robust to cascading effects in marine food webs

Body mass has been shown to scale negatively with abundance in a wide range of habitats and ecosystems. It is believed that this relationship has important consequences for the distribution and maintenance of energy in natural communities. Some studies have shown that the relationship between body mass and abundance may be robust to major food web perturbations, fuelling the belief that natural processes may preserve the slope of this relationship and the associated cycling of energy and nutrients. Here, we use data from a long‐term experimental food web manipulation to examine this issue in a semi‐natural environment. Similar communities were developed in large experimental mesocosms over a six month period. Some of the mesocosms were then subjected to species removals, based on the mean strength of their trophic interactions in the communities. In treatments where the strongest interactors were removed, a community‐level trophic cascade occurred. The biomass density of invertebrates increased dramatically in these communities, which led to a suppression of primary production. In spite of these widespread changes in ecosystem functioning, the slope of the relationship between body mass and abundance remained unchanged. This was the case whether average species body mass and abundance or individual organism size spectra were considered. An examination of changes in species composition before and after the experimental manipulations revealed an important mechanism for maintaining the body mass–abundance relationship. The manipulated communities all had a higher species turnover than the intact communities, with the highest turnover in communities that experienced cascading effects. As some species increased in body mass and abundance, new species filled the available size–abundance niches that were created. This maintained the overall body mass–abundance relationship and provided a stabilising structure to these experimental communities.     

Seed size and shape are not related to persistence in soil in Australia in the same way as in Britain

1. Previous studies have shown that among British species, seeds that persist in the soil tend to be small and compact compared with non-persistent seeds. We tested whether or not this pattern is repeated among 101 Australian species, from a range of habitats.
2. Seed mass was plotted against variance of seed dimensions, across all species. Species with persistent seeds were found across the whole range of seed mass (0·217–648·9 mg) and variance (0·0000–0·2497), providing no evidence for a critical mass or variance which separated persistent from transient seeds.
3. We tested whether or not divergence within individual clades between persistent and transient seeds was associated with increased seed mass or seed dimension variance, using phylogenetically independent contrasts (PICs). There was no consistent tendency found.
4. Thus for Australian species, persistent seeds were not smaller or more compact than transient seeds when compared across all species or when compared using PICs. Presumably the natural history of burial and disturbance operates differently in British and Australian habitats.     

Improved Quality Control Metrics for Cascade Impaction Measurements of Orally Inhaled Drug Products (OIPs)

This study of aerodynamic mass-weighted particle size distribution (APSD) data from orally inhaled products (OIPs) investigated whether a set of simpler (than currently used) metrics may be adequate to detect changes in APSD for quality control (QC) purposes. A range of OIPs was examined, and correlations between mass median aerodynamic diameter and the ratio of large particle mass (LPM) to small particle mass (SPM) were calculated. For an Andersen cascade impactor, the LPM combines the mass associated with particle sizes from impactor stage 1 to a product-specific boundary size; SPM combines the mass of particles from that boundary through to terminal filter. The LPM–SPM boundary should be chosen during development based on the full-resolution impactor results so as to maximize the sensitivity of the LPM/SPM ratio to meaningful changes in quality. The LPM/SPM ratio along with the impactor-sized mass (ISM) are by themselves sufficient to detect changes in central tendency and area under the APSD curve, which are key in vitro quality attributes for OIPs. Compared to stage groupings, this two-metric approach provides better intrinsic precision, in part due to having adequate mass and consequently better ability to detect changes in APSD and ISM, suggesting that this approach should be a preferred QC tool. Another advantage is the possibility to obtain these metrics from the abbreviated impactor measurements (AIM) rather than from full-resolution multistage impactors. Although the boundary is product specific, the testing could be accomplished with a basic AIM system which can meet the needs of most or all OIPs.     

Effect of rearing strategy and gamma radiation on fecundity and fertility of codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae)

The codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) is a serious pest of pome fruit worldwide. In an effort to reduce the use of pesticides to control this pest, the sterile insect technique (SIT) is used or considered for use as a component of area‐wide integrated pest management programmes. Rearing codling moths through diapause has been shown to improve the competitiveness of sterile moths released in orchards, and provides management alternatives that would allow mass‐rearing facilities to increase their yearly production of sterile moths. Because radiosensitivity in insects can be influenced by numerous biological factors, laboratory tests were conducted to examine whether the response to increasing doses of radiation, as expressed in the fecundity and fertility of cohorts of moths, is similar for adult moths mass‐reared through diapause or through standard (non‐diapause) production protocols. Our data revealed that the effect of increasing doses of radiation on fecundity and fertility of codling moths reared through both rearing strategies was similar. In the case of fertility, this is a particularly important finding for the expanded application of codling moth SIT. If mass‐rearing facilities use year‐round diapause rearing, the dose required to treat the insects prior to release will be similar to that used when codling moths are reared through standard production protocols.     

Digestive plasticity as a response to woodland fragmentation in roe deer

Digestive plasticity, which refers to changes in digestive features due to changes in both internal and external environmental conditions, is a crucial factor for understanding the ability of species to cope with environmental changes. In Europe, agricultural intensification and the loss of forests have been major challenges for original forest dwellers, however some species, such as the European roe deer (Capreolus capreolus), have been able to successfully colonize these new habitats. In this work, we investigated the adaptation of some digestive features of roe deer to the agricultural landscapes. We assessed whether changes in local landscape structure influenced the mass of both reticulorumen (RR) and distal fermentation chamber (DFC) of 47 juvenile and adult roe deer inhabiting an agro-ecosystem in southwest France. Woodland cover had a clear effect on diet quality (estimated by the rate of gas production of digestive contents) and DFC weight of animals. In fact, deer from the most forested landscapes showed heavier DFCs and fed on poorer quality diet (lower gas production) than their counterparts from the most open landscapes. RR mass was less influenced by the landscape openness, being the age of animals the main factor for understanding the variations of this digestive feature in our study area. We can conclude that colonizing agricultural landscapes increases the access to highly energetic and digestive resources.     

Seed mass and seed nutrient content as predictors of seed output variation between species

In patch‐occupancy models for vegetation, propagule output per area occupied is a key species trait, influencing the potential to colonize vacant patches, and hence species dynamics and coexistence. We estimated seed output across a range of species and quantified its relationship to seed dry mass, seed N and P content, and accessory costs in fruiting structures. Fruiting and seed production data were obtained for 47 woody perennial species, spanning an almost 3000‐fold range of seed mass, over a period of one year in Ku‐ring‐gai Chase National Park, New South Wales, Australia. Seed output was measured as numbers per m² canopy outline and per m² leaf area.
Of cross‐species variation in seed output per m² canopy outline per year, 72% could be predicted from seed mass alone, with a directly inverse relationship (log‐log slope not significantly different from ?1). Seed output per m² leaf area could be predicted somewhat more tightly (75%), indicating leaf area per canopy outline area accounted for some cross‐species variation. Reproductive production per m² occupied per year varied much less than seed mass and accounted for the remaining variation in seed output. Although accessory costs were about equal in magnitude to seed mass as a component of aggregate investment per seed, they were strongly correlated with seed mass, and consequently did not add substantially to the predictive power.
Total mass of N or P per seed were found to be slightly but significantly better predictors of seed output variation than dry seed mass (83% and 78%, respectively). This supports the idea that mineral nutrients are a more fundamental currency for seed production than dry mass. Seed mass, whether measured as dry mass or as N or P, appears to be the principal driver of variation in seed output per m² occupied, and consequently is among the most important dimensions of ecological variation across coexisting species.     

Epidermal peroxisome proliferator-activated receptor gamma as a target for ultraviolet B radiation

Ultraviolet B radiation (UVB) is a pro-oxidative stressor with profound effects on skin in part through its ability to stimulate cytokine production. Peroxisome proliferator-activated receptor gamma (PPAR gamma) has been shown to regulate inflammatory processes and cytokine release in various cell types. Since the oxidized glycerophospholipid 1-hexadecyl-2-azelaoyl glycerophosphocholine (azPC) has been shown to be a potent PPAR gamma agonist, this study was designed to assess whether the PPAR gamma system is a target for UVB irradiation and involved in UVB-induced inflammation in epidermal cells. The present studies demonstrated the presence of PPAR gamma mRNA and functional protein in human keratinocytes and epithelial cell lines HaCaT, KB, and A431. The treatment of epidermal cells with the PPAR gamma-specific agonist ciglitazone or azPC augmented cyclooxygenase-2 expression and enzyme activity induced by phorbol 12-myristate-13-acetate or interleukin-1 beta. Lipid extracts from the cell homogenate of UVB-irradiated, but not control, cells contained a PPAR gamma-agonistic activity identified by reporter assay, and this activity up-regulated cyclooxygenase-2 expression induced by phorbol 12-myristate-13-acetate. Subjecting purified 1-hexadecyl-2-arachidonoyl-glycerophosphocholine to UVB irradiation generated a PPAR gamma-agonistic activity, among which the specific PPAR gamma agonist azPC was identified by mass spectrometry. These findings suggested that UVB-generated PPAR gamma-agonistic activity was due to the free radical mediated non-enzymatic cleavage of endogenous glycerophosphocholines. Treatment with the specific PPAR gamma antagonist GW9662 or expression of a dominant-negative PPAR gamma mutant in KB cells inhibited UVB-induced epidermal cell prostaglandin E(2) production. These findings suggested that UVB-generated PPAR gamma activity is necessary for the optimal production of epidermal prostaglandins. These studies demonstrated that epithelial cells contain a functional PPAR gamma system, and this system is a target for UVB through the production of novel oxidatively modified endogenous phospholipids.     

Effects of aging and hyperoxia on oxidative damage to cytochrome c in the housefly, Musca domestica

Cytochrome c is a component of the mitochondrial electron transport chain, where it transfers electrons from ubiquinol-cytochrome c reductase to cytochrome c oxidase. Autoxidation of some of the components of the electron transport chain is the main source of intracellular O(2)(-*)/H(2)O(2) production in aerobic organisms. Because cytochrome c is located on the outer surface of the inner mitochondrial membrane, it is likely to be constantly exposed to H(2)O(2), secreted by mitochondria into the cytosol. The specific objective of this study was to determine whether cytochrome c in the flight muscle mitochondria of the housefly is oxidatively damaged during aging and/or under severe oxidative stress induced by exposure of flies to 100% oxygen. Results of two independent methods, namely tritiated borohydride labeling for determining carbonylation and mass spectral analysis for the measurement of molecular mass, indicated that neither the carbonyl level nor the molecular mass of cytochrome c was affected by aging or hyperoxia. Thus, either cytochrome c is resistant to oxidative damage in vivo or the oxidized cytochrome c is promptly degraded. These findings also support the concept that protein oxidative damage during aging and under oxidative stress is selective.     

Temporary flightlessness as a potential cost of reproduction in pre-laying Common Eiders Somateria mollissima

The rapid growth and reabsorption of the avian ovary is thought to be adaptive, as it reduces predation risk and the metabolic cost of flight. In this paper, we use an extreme case of parental investment to show how the survival of gravid birds may be impaired by reduced take-off ability. In still air, temporary flightlessness is regularly observed in female Common Eiders Somateria mollissima preparing for breeding. From a sample of pre-laying females collected in the Baltic Sea, we quantified the relationships among body reserves, organ mass and take-off ability using a general model of take-off performance. Average body mass at the beginning and end of follicular growth was, respectively, 32% and 43% higher than winter body mass. Wing-loading increased significantly during ovary development whereas the relative mass of flight muscles decreased. In contrast, organ mass and somatic body mass were constant from early follicular growth until laying, indicating that the observed increase in body mass was caused by ovary growth. The average specific lift production of individuals collected at the beginning of follicular growth was 9.7 N/kg, which is similar to the lift required to become airborne (9.8 N/kg). As ovary mass increased, lift production decreased to 9.2 N/kg at the onset of laying. These results indicate that temporary flightlessness results from the accumulation of large body reserves and subsequent ovarian growth. Predators of Common Eiders are diverse and may come from air, water and land. We suggest that temporary flightlessness may decrease adult survival through predation, and may represent an important cost of reproduction.     

Autoxidative quinone formation in vitro and metabolite formation in vivo from tea polyphenol (-)-epigallocatechin-3-gallate: studied by real-time mass spectrometry combined with tandem mass ion mapping

(-)-Epigallocatechin-3- gallate (EGCG), the most abundant and biologically active compound in tea, has been proposed to have beneficial health effects, including prevention of cancer and heart disease. Based mainly on studies in cell-line systems, in which EGCG is not stable, different mechanisms of action of EGCG have been proposed. It has been proposed also that oxidation of EGCG and its production of reactive oxygen species are responsible for biological activities such as receptor inactivation and telomerase inhibition. It is unclear, however, whether this phenomenon occurs in vivo. In the present study, the stability of EGCG and product formation in Tris-HCl buffer was investigated using real- time mass spectrometry combined with tandem mass ion mapping. With real-time mass data acquisition, we demonstrate for the first time the formation of EGCG quinone, EGCG dimer quinone, and other related compounds. The structural information of the major appearing ions was provided by tandem mass analysis of each ion. A mechanism for the autoxidation of EGCG based on the structural information of these ions was proposed. None of these oxidation products were observed in the plasma samples of mice after treatment with 50 mg/kg EGCG, i.p. daily for 3 days. Instead, the methylated and conjugated metabolites of EGCG were observed. Therefore the roles of EGCG autoxidation in the biological activities of this compound in vivo remain to be investigated further.