Summary 1 Summary All plants in natural ecosystems appear to be symbiotic with fungal endophytes. This highly diverse group of fungi can have profound impacts on plant communities through increasing fitness by conferring abiotic and biotic stress tolerance, increasing biomass and decreasing water consumption, or decreasing fitness by altering resource allocation. Despite more than 100 yr of research resulting in thousands of journal articles, the ecological significance of these fungi remains poorly characterized. Historically, two endophytic groups (clavicipitaceous (C) and nonclavicipitaceous (NC)) have been discriminated based on phylogeny and life history traits. Here, we show that NC-endophytes represent three distinct functional groups based on host colonization and transmission, in planta biodiversity and fitness benefits conferred to hosts. Using this framework, we contrast the life histories, interactions with hosts and potential roles in plant ecophysiology of C- and NC-endophytes, and highlight several key questions for future work in endophyte biology.

https://courses.washington.edu/cfr523/documents/2009TansleyReview.pdf

Fungal endophytes: diversity and functional roles.

Oxidative stress is a phenomenon caused by an imbalance between production and accumulation of oxygen reactive species (ROS) in cells and tissues and the ability of a biological system to detoxify these reactive products. ROS can play, and in fact they do it, several physiological roles (i.e., cell signaling), and they are normally generated as by-products of oxygen metabolism; despite this, environmental stressors (i.e., UV, ionizing radiations, pollutants, and heavy metals) and xenobiotics (i.e., antiblastic drugs) contribute to greatly increase ROS production, therefore causing the imbalance that leads to cell and tissue damage (oxidative stress). Several antioxidants have been exploited in recent years for their actual or supposed beneficial effect against oxidative stress, such as vitamin E, flavonoids, and polyphenols. While we tend to describe oxidative stress just as harmful for human body, it is true as well that it is exploited as a therapeutic approach to treat clinical conditions such as cancer, with a certain degree of clinical success. In this review, we will describe the most recent findings in the oxidative stress field, highlighting both its bad and good sides for human health.

/pdf/oxidative-stress-harms-and-benefits-for-human-health-1njoes208u.pdf

Oxidative Stress: Harms and Benefits for Human Health

Phenolics and polyphenolics in foods, beverages and spices: Antioxidant activity and health effects – A review

Polyploidy is widely acknowledged as a major mechanism of adaptation and speciation in plants. The stages in polyploid evolution include frequent fertility bottlenecks and infrequent events such as gametic nonreduction and interspecific hybridization, yet little is known about how these and other factors influence overall rates of polyploid formation. Here we review the literature regarding polyploid origins, and quantify parameter values for each of the steps involved in the principal pathways. In contrast to the common claim that triploids are sterile, our results indicate that the triploid bridge pathway can contribute significantly to autopolyploid formation regardless of the mating system, and to allopolyploid formation in outcrossing taxa. We estimate that the total rate of autotetraploid formation is of the same order as the genic mutation rate (10 i5 ), and that a high frequency of interspecific hybridization (0.2% for selfing taxa, 2.7% for outcrossing taxa) is required for the rate of tetraploid formation via allopolyploidy to equal that by autopolyploidy. We conclude that the rate of autopolyploid formation may often be higher than the rate of allopolyploid formation. Further progress toward understanding polyploid origins requires studies in natural populations that quantify: (a) the frequency of unreduced gametes, (b) the effectiveness of triploid bridge pathways, and (c) the rates of interspecific hybridization.

/pdf/pathways-mechanisms-and-rates-of-polyploid-formation-in-45lhl9s528.pdf

Pathways, mechanisms, and rates of polyploid formation in flowering plants

Phenolics in Food and Nutraceuticals is the first single-source compendium of essential information concerning food phenolics. This unique book reports the classification and nomenclature of phenolics, their occurrence in food and nutraceuticals, chemistry and applications, and nutritional and health effects. In addition, it describes antioxidant activity of phenolics in food and nutraceuticals as well as methods for analysis and quantification. Each chapter concludes with an extensive bibliography for further reading. Food scientists, nutritionists, chemists, biochemists, and health professionals will find this book valuable.

Phenolics in food and nutraceuticals

Three proanthocyanidin trimers possessing A-type interflavanoid linkages, epicatechin-(4β→6)-epicatechin-(4β→8, 2β→O→7)-epicatechin (4), epicatechin-(4β→8, 2β→O→7)-epicatechin-(4β→8)-epicatechin (5), and epicatechin-(4β→8)-epicatechin-(4β→8, 2β→O→7)-epicatechin (6), were isolated from the ripe fruits of Vaccinium macrocarpon (cranberry) and prevented adherence of P-fimbriated Escherichia coli isolates from the urinary tract to cellular surfaces containing α-Gal(1→4)β-Gal receptor sequences similar to those on uroepithelial cells. The structure of 4 was elucidated by a combination of spectroscopic methods and acid-catalyzed degradation with phloroglucinol. Also isolated were the weakly active epicatechin-(4β→8, 2β→O→7)-epicatechin (procyanidin A2) (3) and the inactive monomer epicatechin (1) and the inactive dimer epicatechin-(4β→8)-epicatechin (procyanidin B2) (2).

A-Type proanthocyanidin trimers from cranberry that inhibit adherence of uropathogenic P-fimbriated Escherichia coli.

The structure of cranberry proanthocyanidins which inhibit adherence of uropathogenic P-fimbriated Escherichia coli in vitro.

To the Editor: The consumption of cranberry juice has been recommended for the prevention of urinary tract infections, and a 1994 clinical study1 provides scientific validation of this claim. The e...

Inhibition of the adherence of P-fimbriated Escherichia coli to uroepithelial-cell surfaces by proanthocyanidin extracts from cranberries.

Cranberry fruit is a rich source of polyphenols, and has shown biological activities against Streptococcus mutans. In the present study, we examined the influence of extracts of flavonols (FLAV), anthocyanins (A) and proanthocyanidins (PAC) from cranberry on virulence factors involved in Streptococcus mutans biofilm development and acidogenicity. PAC and FLAV, alone or in combination, inhibited the surface-adsorbed glucosyltransferases and F-ATPases activities, and the acid production by S. mutans cells. Furthermore, biofilm development and acidogenicity were significantly affected by topical applications of PAC and FLAV (P<0.05). Anthocyanins were devoid of any significant biological effects. The flavonols are comprised of mostly quercetin glycosides, and the PAC are largely A-type oligomers of epicatechin. Our data show that proanthocyanidins and flavonols are the active constituents of cranberry against S. mutans.

Nicholi Vorsa

Papers

A-Type proanthocyanidin trimers from cranberry that inhibit adherence of uropathogenic P-fimbriated Escherichia coli.

The structure of cranberry proanthocyanidins which inhibit adherence of uropathogenic P-fimbriated Escherichia coli in vitro.

Inhibition of the adherence of P-fimbriated Escherichia coli to uroepithelial-cell surfaces by proanthocyanidin extracts from cranberries.

Inhibitory effects of cranberry polyphenols on formation and acidogenicity of Streptococcus mutans biofilms

Dendrimer Versus Linear Conjugate: Influence of Polymeric Architecture on the Delivery and Anticancer Effect of Paclitaxel