Select Dietary Phytochemicals Function as Inhibitors of COX-1 but Not COX-2

Recent clinical trials raised concerns regarding the cardiovascular toxicity of selective cyclooxygenase-2 (COX-2) inhibitors. Many active dietary factors are reported to suppress carcinogenesis by targeting COX-2. A major question was accordingly raised: why has the lifelong use of phytochemicals that likely inhibit COX-2 presumably not been associated with adverse cardiovascular side effects. To answer this question, we selected a library of dietary-derived phytochemicals and evaluated their potential cardiovascular toxicity in human umbilical vein endothelial cells. Our data indicated that the possibility of cardiovascular toxicity of these dietary phytochemicals was low. Further mechanistic studies revealed that the actions of these phytochemicals were similar to aspirin in that they mainly inhibited COX-1 rather than COX-2, especially at low doses.     

TXNIP Deficiency Exacerbates Endotoxic Shock via the Induction of Excessive Nitric Oxide Synthesis

Thioredoxin-interacting protein (TXNIP) has multiple functions, including tumor suppression and involvement in cell proliferation and apoptosis. However, its role in the inflammatory process remains unclear. In this report, we demonstrate that Txnip^−/− mice are significantly more susceptible to lipopolysaccharide (LPS)-induced endotoxic shock. In response to LPS, Txnip^−/− macrophages produced significantly higher levels of nitric oxide (NO) and inducible nitric oxide synthase (iNOS), and an iNOS inhibitor rescued Txnip^−/− mice from endotoxic shock-induced death, demonstrating that NO is a major factor in TXNIP-mediated endotoxic shock. This susceptibility phenotype of Txnip^−/− mice occurred despite reduced IL-1β secretion due to increased S-nitrosylation of NLRP3 compared to wild-type controls. Taken together, these data demonstrate that TXNIP is a novel molecule that links NO synthesis and NLRP3 inflammasome activation during endotoxic shock.     

Effects of Fragmentation of Evergreen Broad-leaved Forests on Genetic Diversity of Ardisia Crenata var. Bicolor (Myrsinaceae)

Due to the long generation times and high densities, dominant tree species usually did not respond consistently with theoretical predictions to the recent fragmentation. Genetic structures of shrubs and herbs, especially those with low densities, may be more sensitive to forest fragmentation. We studied the genetic structure of a self-compatible subshrub, Ardisia crenata var. bicolor (Myrsinaceae) in a recently fragmented landscape. Ten RAPD primers used for analysis generated a total of 76 bands. We found that A. c. var. bicolor had relatively low species-level (P₉₅ = 63.2%; H = 0.106; Shannon diversity index (SI) = 0.246) and within-population diversity (P₉₅ = 5.3−46.1%; H = 0.026−0.175; SI = 0.032−0.253), and significant population differentiation (G_ST = 0.445). Significantly positive relationships were found between measures of diversity (P₉₅, H and SI) and the log of estimated population size. No significant relationship was observed between Nei's genetic distance and spatial distance of pairwise populations, indicating no isolation-by-distance. Given most species of forests are shrubs and herbs with short generation times, our observation indicated that distinct genetic consequences of recent fragmentation may be expected for quite a number of plant species.     

Invasive alien plants in China: role of clonality and geographical origin

Biological invasions have become a significant threat to the global environment. Unfortunately, to date there is no consensus on invasion mechanisms and predictive models. Controversies range from whether we can reliably predict which species may become invasive to which species characteristics (e.g., life history, taxonomic groups, or geographic origin) contribute to the invasion processes. We examined 126 invasive alien plant species in China to understand the role of clonality and geographical origin in their invasion success. These species were categorized into three groups (I, II, III) based on their invasiveness in terms of current spatial occupation and the degree of damage to invaded habitats. Clonal plants consisted of almost half (44%) of the 126 invasive species studied, and consisted of 66% of 32 the most invasive alien plant species (Group I). There was a significant positive relationship between clonality and species invasiveness. A 68% of the 126 species studied originated in the continent of America (North and/or South America). These preliminary findings support that America is the primary geographical origin of invasive alien plant species in China and that clonality of the invasive plant species contributed significantly to the their invasiveness. The results suggest an urgent need at the global scale to investigate the mechanisms whereby plant clonal growth influences plant invasions, and the need for a focus at regional scale to examine factors affecting the exchange of invasive plant species between America and China.     

Genetic diversity within Oryza rufipogon germplasms preserved in Chinese field gene banks of wild rice as revealed by microsatellite markers

Nineteen microsatellite markers were employed to evaluate the genetic diversity of 92 accessions of common wild rice Oryza rufipogon Griff., which represent a significant portion of the distribution range from field gene banks of China. In comparison, a total of 57 varieties from most of the rice growing areas in China were also analyzed. The microsatellite analysis revealed a considerable amount of genetic diversity resided within the preserved wild rice germplasms. In all, the nineteen microsatellites revealed 328 alleles. The number of alleles per locus varied widely among these markers, ranging from 6 at RM242 to 30 at RM206. A comparison of the genetic parameters showed that wild rice strains preserved in the field gene banks (na = 17.27; R _S = 15.66; H _S = 0.86; H _T = 0.852; H _O = 0.307) possess much higher genetic diversity than cultivated rice varieties (na = 8.27; R _S = 8.14; H _S = 0.75; H _T = 0.758; H _O = 0.051). A total of 196 alleles detected in the wild rice could not be found in cultivated rice, suggesting that about 60% of the alleles of wild rice might be lost during the process of rice domestication. This result shows that these ex situ preserved wild rice strains are of great importance for the discovery and utilization of novel genes in the future rice breeding practices. Considerably abundant genetic variability detected within the studied wild rice germplasms could be comparable to that previously found in a wide sampling of 47 natural populations (na = 16.17; H _S = 0.67; H _O = 0.229), demonstrating that developing field gene banks of wild rice is a necessary and efficient way for preserving genetic diversity of wild rice resources. To determine minimum microsatellites that could distinguish these wild rice accessions, the phylogenetic trees constructed by means of the combinations of different microsatellites suggested that the five highly polymorphic microsatellites could clearly identify these samples. High polymorphisms of rice microsatellite loci and their great resolving power will be particularly helpful for germplasm evaluation and evolutionary studies for better strengthening the conservation and utilization of genetic diversity of wild rice in the field gene banks.     

Morphology and Phase Behavior of Two-Component Lipid Membranes

The stability and shapes of domains with different bending rigidities in lipid membranes are investigated. These domains can be formed from the inclusion of an impurity in a lipid membrane or from the phase separation within the membrane. We show that, for weak line tensions, surface tensions and finite spontaneous curvatures, an equilibrium phase of protruding circular domains or striped domains may be obtained. We also predict a possible phase transition between the investigated morphologies.     

Binding of fluphenazine with human serum albumin in the presence of rutin and quercetin: An evaluation of food‐drug interaction by spectroscopic techniques

The interactions between human serum albumin (HSA) and fluphenazine (FPZ) in the presence or absence of rutin or quercetin were studied by fluorescence, absorption and circular dichroism (CD) spectroscopy and molecular modeling. The results showed that the fluorescence quenching mechanism was static quenching by the formation of an HSA–FPZ complex. Entropy change (ΔS ⁰) and enthalpy change (ΔH ⁰) values were 68.42 J/(mol? K) and ?4.637 kJ/mol, respectively, which indicated that hydrophobic interactions and hydrogen bonds played major roles in the acting forces. The interaction process was spontaneous because the Gibbs free energy change (ΔG ⁰) values were negative. The results of competitive experiments demonstrated that FPZ was mainly located within HSA site I (sub‐domain IIA). Molecular docking results were in agreement with the experimental conclusions of the thermodynamic parameters and competition experiments. Competitive binding to HSA between flavonoids and FPZ decreased the association constants and increased the binding distances of FPZ binding to HSA. The results of absorption, synchronous fluorescence, three‐dimensional fluorescence, and CD spectra showed that the binding of FPZ to HSA caused conformational changes in HSA and simultaneous effects of FPZ and flavonoids induced further HSA conformational changes.     

Bioclimatic transect networks: Powerful observatories of ecological change

Transects that traverse substantial climate gradients are important tools for climate change research and allow questions on the extent to which phenotypic variation associates with climate, the link between climate and species distributions, and variation in sensitivity to climate change among biomes to be addressed. However, the potential limitations of individual transect studies have recently been highlighted. Here, we argue that replicating and networking transects, along with the introduction of experimental treatments, addresses these concerns. Transect networks provide cost‐effective and robust insights into ecological and evolutionary adaptation and improve forecasting of ecosystem change. We draw on the experience and research facilitated by the Australian Transect Network to demonstrate our case, with examples, to clarify how population‐ and community‐level studies can be integrated with observations from multiple transects, manipulative experiments, genomics, and ecological modeling to gain novel insights into how species and systems respond to climate change. This integration can provide a spatiotemporal understanding of past and future climate‐induced changes, which will inform effective management actions for promoting biodiversity resilience.