Centipedes are one of the oldest terrestrial arthropods belonging to the sub phylum Myriapoda. With the expansion of our understanding of the application of the two centipedes Scolopendra morsitans and Scolopendra hainanum, belonging to the order Scolopendromorpha, an exhaustive classification was required. Although consensus has been reached on the phylogeny of Chilopoda based on morphological traits, recent analyses based on molecular data exhibited differences in results.
Methods and results
The mitochondrial genome sequences of S. morsitans and S. hainanum were obtained by next-generation sequencing. S. morsitans contains 13 PCGs, two rRNAs, 11 tRNAs, and one CR. whereas S. hainanum contains 12 PCGs, of which ATP8 remains unpredicted, two rRNAs, 14 tRNAs, and one CR. An obvious tRNA rearrangement was found in the genus Scolopendra. S. morsitans exhibited a loss of trnW, trnC, trnI, trnK, trnD, trnA, trnN, trnQ, trnF, trnT, trnS, trnL, and trnV, and a repeat of trnR and trnL. S. hainanum exhibited a loss of trnQ, trnC, trnW, trnI, trnD, trnQ, trnP, and trnV. Phylogenetic analyses of centipedes based on 12 PCGs supported the sister relationship between the orders Geophilomorpha and Lithobiomorpha and a close relationship between Scolopendra dehaani and S. hainanum.
Conclusions
The new mitogenomes determined in this study provide new genomic resources for gene rearrangements and contribute to the understanding of the evolution of gene rearrangement in Chilopoda.
A novel reductive compound with molecular weight of about 1000 Da, named Pc reducer, was purified from the liquid culture of a white-rot basidiomycete Phanerochaetechrysosporium. It was likely to have an alkene-ester structure according to Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectra. Pc reducer reduced the hydroxyl radical HO and the stable nitroxide radical under certain conditions. It inhibited the repolymerization of the products from the oxidation of phenolic lignin-model compounds by reducing certain intermediate radicals. The activity of manganese peroxidases was promoted by Pc reducer at certain concentrations. Pc reducer could also weaken the repolymerization of fragments from the oxidation of Na-lignosulfonate by lignin peroxidases and manganese peroxidases. It has potential ability to improve the ligninolytic efficiency of peroxidases in P. chrysosporium. 相似文献
The carotenoid synthetic genes, crtM and crtN, derived from Staphylococcus aureus, were introduced into B. subtilis, resulting in yellow pigmentation. Absorption maxima of pigments and MALDI-TOF mass spectrometry demonstrated that the pigmented
strain accumulated two C30 carotenoids, 4,4′-diapolycopene and 4,4′-diaponeurosporene. A survival test using H2O2 revealed that the pigmented strain was more resistant to oxidative stress than the strain harboring an empty-vector. These
findings indicate that B.subtilis can produce carotenoids, and the strain accumulating the carotenoids, CarotenoBacillus, will become a basal host for production
of C30 carotenoids and evaluation of their antioxidative effects. 相似文献
Efficient communication between the cell and its external environment is of the utmost importance to the function of multicellular
organisms. While signaling events can be generally characterized as information exchange by means of controlled energy conversion,
research efforts have hitherto mainly been concerned with mechanisms involving chemical and electrical energy transfer. Here,
we review recent computational efforts addressing the function of mechanical force in signal transduction. Specifically, we
focus on the role of steered molecular dynamics (SMD) simulations in providing details at the atomic level on a group of protein
domains, which play a fundamental role in signal exchange by responding properly to mechanical strain. We start by giving
a brief introduction to the SMD technique and general properties of mechanically stable protein folds, followed by specific
examples illustrating three general regimes of signal transfer utilizing mechanical energy: purely mechanical, mechanical
to chemical, and chemical to mechanical. Whenever possible the physiological importance of the example at hand is stressed
to highlight the diversity of the processes in which mechanical signaling plays a key role. We also provide an overview of
future challenges and perspectives for this rapidly developing field. 相似文献
The chitosan with three-dimensional porous structure greatly increased the effective electrode surface for loading of platinum nanoparticles and promoted efficient electron transfer. The resulting biosensor had a response time (within 5 s) and a linear response from 6 μM to 4.2 mM glucose with a detection limit of 2 μM (S/N = 3). Moreover, the methodology can be applied for the immobilization of other enzymes. 相似文献
Cell-penetrating peptides (CPPs), which are usually short basic peptides, are able to cross cell membranes and convey bioactive
cargoes inside cells. CPPs have been widely used to deliver inside cells peptides, proteins, and oligonucleotides; however,
their entry mechanisms still remain controversial. A major problem concerning CPPs remains their lack of selectivity to target
a specific type of cell and/or an intracellular component. We have previously shown that myristoylation of one of these CPPs
affected the intracellular distribution of the cargo. We report here on the synthesis of glycosylated analogs of the cell-penetrating
peptide (R6/W3): Ac-RRWWRRWRR-NH2. One, two, or three galactose(s), with or without a spacer, were introduced into the sequence of this nonapeptide via a triazole link, the Huisgen reaction being achieved on a solid support. Four of these glycosylated CPPs were coupled via a disulfide bridge to the proapoptotic KLAK peptide, (KLAKLAKKLAKLAK), which alone does not enter into cells. The effect
on cell viability and the uptake efficiency of different glycosylated conjugates were studied on CHO cells and were compared
to those of the nonglycosylated conjugates: (R6/W3)S-S-KLAK and penetratinS-S-KLAK. We show that glycosylation significantly
increases the cell viability of CHO cells compared to the nonglycosylated conjugates and concomitantly decreases the internalization
of the KLAK cargo. These results suggest that glycosylation of CPP may be a key point in targeting specific cells. 相似文献
A disintegrin and metalloprotease 12 (ADAM12-S) has previously been reported to be significantly reduced in maternal serum
from women with fetal aneuploidy early in the first trimester and to significantly improve the quality of risk assessment
for fetal trisomy 21 in prenatal screening. The aim of this study was to determine whether ADAM12-S is a useful serum marker
for fetal trisomy 21 using the mixture model. 相似文献
In this work, the forward and back extraction of soybean protein by reverse micelles was studied. The reverse micellar systems
were formed by anionic surfactant sodium bis(2-ethyl hexyl) sulfosuccinate (AOT), isooctane and KCl solution. The effects
of AOT concentration, aqueous pH, KCl concentration and phase volume ratio on the extraction efficiency of soybean protein
were tested. Suitability of reverse micelles of AOT and Triton-X-100/AOT mixture in organic solvent toluene for soybean protein
extraction was also investigated. The experimental results lead to complete forward extraction at the AOT concentration 120 mmol l−1, aqueous pH 5.5 and KCl concentration 0.8 mol l−1. The backward extraction with aqueous phase (pH 5.5) resulted in 100% extraction of soybean protein from the organic phase. 相似文献