Ponapensin, a cyclopenta[bc]benzopyran with potent NF-kappaB inhibitory activity from Aglaia ponapensis

Two new compounds, a cyclopenta[bc]benzopyran, ponapensin (1), and an aglaialactone, 5,6-desmethylenedioxy-5-methoxy-aglalactone (2), together with nine known compounds were isolated from the CHCl(3) soluble extract of the leaves and twigs of Aglaia ponapensis. Their structures were established by spectroscopic data interpretation. Ponapensin (1) exhibited significant NF-kappaB inhibitory activity in an Elisa assay, and was found to be more potent than the positive control rocaglamide. All of the compounds isolated were also tested in a panel of human cancer cell lines, with the known sterol E-volkendousin (3) and methyl rocaglate (aglafoline) found to be the only active substances.     

Quinoline alkaloids from Acronychia laurifolia.

Bioassay-directed fractionation of a root extract of Acronychia laurifolia (Rutaceae) using the KB-V1+ human tumor cell line led to the isolation of six quinoline alkaloids. One of these alkaloids is novel, namely, 2,3-methylenedioxy-4,7-dimethoxyquinoline and the other five were identified as the known compounds, evolitrine, gamma-fagarine, skimmianine, kokusaginine and maculosidine. Two known bis-tetrahydrofuran lignans, sesamolin and yangambin, were also identified. The structure of the new alkaloid was determined by spectroscopic methods. All of the isolates were evaluated against a panel of human cancer cell lines; four of the alkaloids showed weak cytotoxic activity.     

Simulated sea level change alters anatomy, physiology, growth, and reproduction of red mangrove (Rhizophora mangle L.)

Tropical coastal forests – mangroves – will be one of the first ecosystems to be affected by altered sea levels accompanying global climate change. Responses of mangrove forests to changing sea levels depend on reactions of individual plants, yet such responses have not been addressed experimentally. We report data from a long-term greenhouse study that assessed physiological and individual growth responses of the dominant neotropical mangrove, Rhizophora mangle, to levels of inundation expected to occur in the Caribbean within 50–100 years. In this study, we grew potted plants in tanks with simulated semidiurnal (twice daily) high tides that approximated current conditions (MW plants), a 16-cm increase in sea level (LW plants), and a 16-cm decrease in sea level (HW plants). The experiment lasted 2½ years, beginning with mangrove seedlings and terminating after plants began to reproduce. Environmental (air temperature, relative humidity, photosynthetically active radiation) and edaphic conditions (pH, redox, soil sulfide) approximated field conditions in Belize, the source locale for the seedlings. HW plants were shorter and narrower, and produced fewer branches and leaves, responses correlated with the development of acid-sulfide soils in their pots. LW plants initially grew more rapidly than MW plants. However, the growth of LW plants slowed dramatically once they reached the sapling stage, and by the end of the experiment, MW plants were 10–20% larger in all measured growth parameters. Plants did not exhibit differences in allometric growth as a function of inundation. Anatomical characteristics of leaves did not differ among treatments. Both foliar C:N and root porosity decreased from LW through MW to HW. Relative to LW and HW plants, MW plants had 1–7% fewer stomata/mm², 6–21% greater maximum photosynthetic rates, 3–23% greater absolute relative growth rates (RGRs), and a 30% higher RGR for a given increase in net assimilation rate. Reduced growth of R. mangle under realistic conditions approximating future inundation depths likely will temper projected increased growth of this species under concomitant increases in the atmospheric concentration of CO₂.     

The Universal Epitope of Influenza A Viral Neuraminidase Fundamentally Contributes to Enzyme Activity and Viral Replication

The only universally conserved sequence among all influenza A viral neuraminidases is located between amino acids 222 and 230. However, the potential roles of these amino acids remain largely unknown. Through an array of experimental approaches including mutagenesis, reverse genetics, and growth kinetics, we found that this sequence could markedly affect viral replication. Additional experiments revealed that enzymes with mutations in this region demonstrated substantially decreased catalytic activity, substrate binding, and thermostability. Consistent with viral replication analyses and enzymatic studies, protein modeling suggests that these amino acids could either directly bind to the substrate or contribute to the formation of the active site in the enzyme. Collectively, these findings reveal the essential role of this unique region in enzyme function and viral growth, which provides the basis for evaluating the validity of this sequence as a potential target for antiviral intervention and vaccine development.     

Androgen of the human prostate.

The relationship between the concentrations of total and apparent free testosterone in the plasma and the levels of testosterone (T), dihydrotestosterone (DHT) and 5 alpha-androstan-3-alpha, 17 beta-diol (DIOL) in 13 benign hypertrophic and 6 carcinomatous prostates was studied. The androgen concentration within both types of glands was nearly 4-fold that in the blood but bore no direct relationship to the blood level. About 75% of the androgen in the tissue was DHT. The most striking finding was that, in spite of a 25.5% less concentrated pool of apparent free testosterone in the blood, the level of T and its metabolites in the cancer tissue was 29% above that in the samples of benign hypertrophic prostate.     

The pharmacognosy of Humulus lupulus L. (hops) with an emphasis on estrogenic properties

As the population ages, there is an ever-increasing need for therapeutic agents that can be used safely and efficaciously to manage symptoms related to postmenopausal estrogen deficiency. Endogenous estrogens, e.g., 17beta-estradiol, of exogenous mammalian origin, e.g., horses, have long been used to manage such symptoms. There are more than 20 different classes of phytochemicals that have demonstrated affinity for human estrogen receptors in vitro. Some studies on exogenous estrogenic substances of botanical origin (phytoestrogens), such as standardized formulations of plant extracts with in vitro and in vivo estrogenic activity from soy (Glycine max Merill.) and red clover (Trifolium pratense L.), suggest clinical efficacy. Few clinical data for phytoestrogens other than isoflavonoids are available. In an exhaustive review of the literature through 2003, only two clinical trials were identified that were designed to evaluate the effect of hops (Humulus lupulus L.) on symptoms related to menopause. Folkloric, chemical, and biological literature relating primarily to the use of hops for their estrogenic activity, and two human clinical trials, are reviewed.     

Historical Maps from Modern Images: Using Remote Sensing to Model and Map Century-Long Vegetation Change in a Fire-Prone Region

Understanding the age structure of vegetation is important for effective land management, especially in fire-prone landscapes where the effects of fire can persist for decades and centuries. In many parts of the world, such information is limited due to an inability to map disturbance histories before the availability of satellite images (~1972). Here, we describe a method for creating a spatial model of the age structure of canopy species that established pre-1972. We built predictive neural network models based on remotely sensed data and ecological field survey data. These models determined the relationship between sites of known fire age and remotely sensed data. The predictive model was applied across a 104,000 km² study region in semi-arid Australia to create a spatial model of vegetation age structure, which is primarily the result of stand-replacing fires which occurred before 1972. An assessment of the predictive capacity of the model using independent validation data showed a significant correlation (r_s = 0.64) between predicted and known age at test sites. Application of the model provides valuable insights into the distribution of vegetation age-classes and fire history in the study region. This is a relatively straightforward method which uses widely available data sources that can be applied in other regions to predict age-class distribution beyond the limits imposed by satellite imagery.     

The Loss of Species: Mangrove Extinction Risk and Geographic Areas of Global Concern

Mangrove species are uniquely adapted to tropical and subtropical coasts, and although relatively low in number of species, mangrove forests provide at least US $1.6 billion each year in ecosystem services and support coastal livelihoods worldwide. Globally, mangrove areas are declining rapidly as they are cleared for coastal development and aquaculture and logged for timber and fuel production. Little is known about the effects of mangrove area loss on individual mangrove species and local or regional populations. To address this gap, species-specific information on global distribution, population status, life history traits, and major threats were compiled for each of the 70 known species of mangroves. Each species'' probability of extinction was assessed under the Categories and Criteria of the IUCN Red List of Threatened Species. Eleven of the 70 mangrove species (16%) are at elevated threat of extinction. Particular areas of geographical concern include the Atlantic and Pacific coasts of Central America, where as many as 40% of mangroves species present are threatened with extinction. Across the globe, mangrove species found primarily in the high intertidal and upstream estuarine zones, which often have specific freshwater requirements and patchy distributions, are the most threatened because they are often the first cleared for development of aquaculture and agriculture. The loss of mangrove species will have devastating economic and environmental consequences for coastal communities, especially in those areas with low mangrove diversity and high mangrove area or species loss. Several species at high risk of extinction may disappear well before the next decade if existing protective measures are not enforced.