In vivo antioxidant activities of essential oils and their constituents from leaves of the Taiwanese Cinnamomum osmophloeum

Cinnamomum osmophloeum Kaneh is an indigenous tree species in Taiwan. In this study, phytochemical characteristics and antioxidant activities of the essential oils and key constituents from the leaves of two C. osmophloeum clones were investigated. The two trees possess two chemotypes, which were classified as the cinnamaldehyde type and camphor type. We demonstrated that the essential oils from C. osmophloeum leaves exerted in vivo antioxidant activities in Caenorhabditis elegans. In addition, trans-cinnamaldehyde and D-(+)-camphor, which respectively represent the major compounds in the cinnamaldehyde-type and camphor-type trees, exerted significant in vivo antioxidant activities against juglone-induced oxidative stress in C. elegans. Moreover, expressions of antioxidative-related genes, including superoxide dismutase (SOD) and glutathione S-transferase (GST), were significantly induced by trans-cinnamaldehyde and D-(+)-camphor from C. osmophloeum leaves. Our results showed that the essential oils from C. osmophloeum leaves and their major compounds might have good potential for further development as nutraceuticals or antioxidant remedies.     

Population genetics of red imported fire ant in Taiwan

In the case of recently established populations of Solenopsis invicta in Taiwan,analysis of genetic variation may provide various dimensions regarding the historical demographic events of this invasive species,which represents a novel opportunity to study the genetic consequences of invasiveness over an ex- tremely short time period.Here we describe genetic structure of two introduced S.invicta populations, Taoyuan and Chiayi,in Taiwan using two classes of markers,nuclear(microsatellites)and mitochondrial (mtDNA)genomes.Pronounced regional differentiation inferred from either AMOVA or Bayesian clustering approach at both genomes suggests that the two populations most likely originate from separate introductions. Furthermore,significant mtDNA but not nuclear differentiation between sympatric social forms suggests two scenarios that interform gene flow is mainly mediated by males,and queens of each form commonly fail to become egg-layers of alternate form.Isolation by distance(IBD)obtained from microsatellites is absent in monogynes,indicating sexuals of this form retain the superior dispersal ability to homogenize the nuclear sig- nature among spatially isolated areas;however,lack of IBD in less vagile polygyne may result from frequent human mediated jump dispersal that erodes the geographical restrictions of genetic exchange.The patterns observed here not only provide insights into how social organization influences the interform gene flow but also reinforce different breeding strategies pursued by two forms in the character of shaping the genetic varia- tion at two levels of genomes.     

Global invasion history of the fire ant Solenopsis invicta

The fire ant Solenopsis invicta is a significant pest that was inadvertently introduced into the southern United States almost a century ago and more recently into California and other regions of the world. An assessment of genetic variation at a diverse set of molecular markers in 2144 fire ant colonies from 75 geographic sites worldwide revealed that at least nine separate introductions of S. invicta have occurred into newly invaded areas and that the main southern U.S. population is probably the source of all but one of these introductions. The sole exception involves a putative serial invasion from the southern United States to California to Taiwan. These results illustrate in stark fashion a severe negative consequence of an increasingly massive and interconnected global trade and travel system.     

Apoptosis induction in BEFV-infected Vero and MDBK cells through Src-dependent JNK activation regulates caspase-3 and mitochondria pathways

Our previous report demonstrated that bovine ephemeral fever virus (BEFV)-infected cultured cells could induce caspase-dependent apoptosis. This study aims to further elucidate how BEFV activates the caspase cascade in bovine cells. BEFV replicated and induced apoptosis in Vero and Madin-Darby bovine kidney (MDBK) cells, and a kinetic study showed a higher efficiency of replication and a greater apoptosis induction ability of BEFV in Vero cells. Src and c-Jun N-terminal kinase (JNK) inhibitor, but not extracellular signal-regulated kinase (ERK) or p38 inhibitor, alleviated BEFV-mediated cytopathic effect and apoptosis. In BEFV-infected Vero and MDBK cells, BEFV directly induced Src tyrosine-418 phosphorylation and JNK phosphorylation and kinase activity, which was inhibited specifically by SU6656 and SP600125, respectively. The caspase cascade and its downstream effectors, Poly (ADP-ribose) polymerase (PARP) and DFF45, were also activated simultaneously upon BEFV infection. In addition, cytochrome c, but not Smac/DIABLO, was released gradually from mitochondria after BEFV infection. SU6656 suppressed Src, JNK, and caspase-3 and -9 activation, as well as PARP and DFF45 cleavage; SP600125 reduced JNK and caspase-3 and -9 activation, as well as PARP and DFF45 cleavage. Taken together, these results strongly support the hypothesis that a Src-dependent JNK signaling pathway plays a key role in BEFV-induced apoptosis. The molecular mechanism identified in our study may provide useful information for the treatment of BEFV.