Fossilized biophotonic nanostructures reveal the original colors of 47-million-year-old moths

Structural colors are generated by scattering of light by variations in tissue nanostructure. They are widespread among animals and have been studied most extensively in butterflies and moths (Lepidoptera), which exhibit the widest diversity of photonic nanostructures, resultant colors, and visual effects of any extant organism. The evolution of structural coloration in lepidopterans, however, is poorly understood. Existing hypotheses based on phylogenetic and/or structural data are controversial and do not incorporate data from fossils. Here we report the first example of structurally colored scales in fossil lepidopterans; specimens are from the 47-million-year-old Messel oil shale (Germany). The preserved colors are generated by a multilayer reflector comprised of a stack of perforated laminae in the scale lumen; differently colored scales differ in their ultrastructure. The original colors were altered during fossilization but are reconstructed based upon preserved ultrastructural detail. The dorsal surface of the forewings was a yellow-green color that probably served as a dual-purpose defensive signal, i.e. aposematic during feeding and cryptic at rest. This visual signal was enhanced by suppression of iridescence (change in hue with viewing angle) achieved via two separate optical mechanisms: extensive perforation, and concave distortion, of the multilayer reflector. The fossils provide the first evidence, to our knowledge, for the function of structural color in fossils and demonstrate the feasibility of reconstructing color in non-metallic lepidopteran fossils. Plastic scale developmental processes and complex optical mechanisms for interspecific signaling had clearly evolved in lepidopterans by the mid-Eocene.     

Soil moisture condition and soil nitrogen dynamics in a pure Alnus japonica forest in Korea

This study was conducted to examine the influences of soil-moisture conditions on soil nitrogen (N) dynamics, including in situ soil N mineralization, N availability, and denitrification in a pure Alnus japonica forest located in Seoul, central Korea. The soil N mineralization, N availability, and denitrification were determined using the buried bag incubation method, ion exchange resin bag method, and acetylene block method, respectively. The annual net N mineralization rate (kg N ha⁻¹ year⁻¹) and annual N availability (mg N bag⁻¹) were 40.26 and 80.65 in the relatively dry site, −5.43 and 45.39 in the moist site, and 7.09 and 39.17 in the wet site, respectively. The annual net N mineralization rate and annual N availability in the dry site were significantly higher than those in the moist and wet sites, whereas there was no significant difference between the moist and wet sites. The annual mean denitrification rate (kg N ha⁻¹ year⁻¹) in the dry, moist, and wet sites was 2.37, 2.76, and 1.59, respectively. However, there was no significant difference among sites due to the high spatial and temporal variations. Our results indicate that soil-moisture condition influenced the in situ N mineralization and resin bag N availability in an A. japonica forest, and treatments of proper drainage for poorly drained sites would increase soil N mineralization and N availability and consequently be useful to conserve and manage the A. japonica forest.     

AtPDR12 contributes to lead resistance in Arabidopsis

Arabidopsis (Arabidopsis thaliana) contains about 130 ATP-binding cassette (ABC) proteins, which are likely to contribute to the transport of diverse materials, including toxic substances. However, the substrates of ABC transporters remain unknown in most cases. We tested which ABC transporter is involved in detoxification of lead [Pb(II)]. Among the many tested, we found that the message level of only AtPDR12 increased in both shoots and roots of Pb(II)-treated Arabidopsis, suggesting that it may be involved in the detoxification of Pb(II). AtPDR12-knockout plants (atpdr12) were used to further test this possibility. In Pb(II)-containing medium, atpdr12 plants grew less well and had higher Pb contents than those of wild-type plants. In contrast, AtPDR12-overexpressing Arabidopsis plants were more resistant to Pb(II) and had lower Pb contents than wild-type plants. The mutant phenotypes and their Pb contents, as well as the localization of the GFP:AtPDR12 fusion protein at the plasma membrane, suggest that AtPDR12 functions as a pump to exclude Pb(II) and/or Pb(II)-containing toxic compounds from the cytoplasm. Inhibition of glutathione synthesis by addition of buthionine sulfoximine to the growth medium exacerbated the Pb(II)-sensitive phenotype of atpdr12 plants, consistent with a glutathione-dependent detoxification mechanism operating in parallel with an AtPDR12-dependent mechanism. Thus, we propose that AtPDR12 is an ABC transporter that contributes to Pb(II) resistance in Arabidopsis.     

Inhibition of inducible nitric oxide synthase and cyclooxygenase II by Platycodon grandiflorum saponins via suppression of nuclear factor-kappaB activation in RAW 264.7 cells

Saponins are glycosidic compounds present in many edible and inedible plants. They exhibit potent biological activities in mammalian systems, including several beneficial effects such as anti-inflammation and immunomodulation. In this study, we investigated the effects of seven platycodin saponins on the activities of inducible nitric oxide synthase (iNOS) and cyclooxygenase II (COX-2) in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. We found that 2"-O-acetyl polygalacin D (S1), platycodin A (S2), platycodin D (S3), and polygalacin D (S6) inhibited LPS-induced NO production in a concentration-dependent manner. Furthermore, these compounds inhibited the expression of LPS-induced iNOS and COX-2 protein and mRNA without an appreciable cytotoxic effect on RAW 264.7 macrophages, and could suppress induction by LPS of pro-inflammatory cytokines such as prostaglandin E2 (PGE2). Treatment with these compounds of RAW 264.7 cells transfected with a reporter construct indicated a reduced level of LPS-induced nuclear factor-kappaB (NF-kappaB) activity and effectively lowered NF-kappaB binding as measured by electrophoretic mobility shift assay (EMSA). The suppression of NF-kappaB activation appears to occur through the prevention of inhibitor kappaB (IkappaB) degradation. In vivo, platycodin saponin mixture (PS) and S3 protected mice from the lethal effects of LPS. The 89% lethality induced by LPS/galactosamine was reduced to 60% and 50% when PS and S3, respectively, were administered simultaneously with LPS. These results suggest that the main inhibitory mechanism of the platycodin saponins may be the reduction of iNOS and COX-2 gene expression through blocking of NF-kappaB activation.     

Karyotype of North American shortnose sturgeon Acipenser brevirostrum with the highest chromosome number in the Acipenseriformes

The shortnose sturgeon Acipenser brevirostrum was revealed to have a larger number of chromosomes than previously reported for other sturgeon species. Its chromosome number ranged from 362 to 372 (of ten specimens examined), showing intraindividual variation. The karyotype of metaphase with the highest chromosome number (372) consisted of 89 pairs of macrochromosomes and 97 pairs of microchromosomes (fundamental number; NF=550). Although the microchromosomes were relatively shorter than the macrochromosomes, most of them had discernible arms and centromeres. Silver-stained nucleolar organizer regions (Ag-NORs) were localized on the telomeric regions of 5 pairs of chromosomes (Ag-NORs=10): 4 were made up of small meta/submetacentrics and 1 of acrocentrics. Polyploidy of A. brevirostrum should be hexaploid based on the karyotype, numerous chromosomes, Ag-NORs, and previously reported large genome size (ca. 13pg DNA/cell).Supplementary material to this paper is available in electronic format at http://dx.doi.org/10.1007/s10228-004-0257-z     

Controlled transcriptional regulation in eukaryotes by a novel transcription factor derived from Escherichia coli purine repressor

Neb-LFamide or AYRKPPFNGSLFamide was originally purified from the grey flesh fly Neobellieria bullata as a myotropic neuropeptide. We studied the occurrence of this peptide and its isoforms in the central nervous system of different insect species by means of whole mount fluorescence immunohistochemistry, mass spectrometry, and data mining. We found that both sequence and immunoreactive distribution pattern are very conserved in the studied insects. In all species and stages we counted two pairs of immunoreactive cells in the pars intercerebralis. These cells projected axons throughout the ventral nerve cord. In the adult CNSs they formed a large number of immunoreactive varicosities as well. Mass spectrometry and data mining revealed that SIFamide exists in two isoforms: [G1]-SIFamide and [A1]-SIFamide. In addition, the SIFamide joining peptide is relatively well conserved throughout arthropod species. The conserved presence of two cysteine residues, separated by six amino acid residues, allows the formation of disulphide bridges.     

Eotaxin and monocyte chemotactic protein-3 use different modes of action

Eotaxin selectively binds CC chemokine receptor (CCR) 3, whereas monocyte chemotactic protein (MCP)-3 binds CCR1, CCR2, and CCR3. To identify the functional determinants of the chemokines, we generated four reciprocal chimeric chemokines-M10E9, M22E21, E8M11, and E20M23-by shuffling the N-terminus and N-loop of eotaxin and MCP-3. M22E21 and E8M11, which shared the N-loop from MCP-3, bound to monocytes with high affinity, and activated monocytes. In contrast, M10E9 and E20M23, which lacked the N-loop, failed to bind and transduce monocyte responses, identifying the N-loop of MCP-3 as the selectivity determinant for CCR1/CCR2. A BIAcore assay with an N-terminal peptide of CCR3 (residues 1-35) revealed that all chimeras except E20M23 exhibited varying degrees of binding affinity with commensurate chemotaxis activity of eosinophils. Surprisingly, E20M23 could neither bind the CCR3 peptide nor activate eosinophils, despite having both N-terminal motifs from eotaxin. These results suggest that the two N-terminal motifs of eotaxin must cooperate with other regions to successfully bind and activate CCR3.     

An Insect Multiligand Recognition Protein Functions as an Opsonin for the Phagocytosis of Microorganisms

We characterize a novel pathogen recognition protein obtained from the lepidopteran Galleria mellonella. This protein recognizes Escherichia coli, Micrococcus luteus, and Candida albicans via specific binding to lipopolysaccharides, lipoteichoic acid, and β-1,3-glucan, respectively. As a multiligand receptor capable of coping with a broad variety of invading pathogens, it is constitutively produced in the fat body, midgut, and integument but not in the hemocytes and is secreted into the hemolymph. The protein was confirmed to be relevant to cellular immune response and to further function as an opsonin that promotes the uptake of invading microorganisms into hemocytes. Our data reveal that the mechanism by which a multiligand receptor recognizes microorganisms contributes substantially to their phagocytosis by hemocytes. A better understanding of an opsonin with the required repertoire for detecting diverse invaders might provide us with critical insights into the mechanisms underlying insect phagocytosis.