Natural diterpenoid EKO activates deubiqutinase ATXN3 to preserve vascular endothelial integrity and alleviate diabetic retinopathy through c-fos/focal adhesion axis.

Diabetic retinopathy (DR) is one of the most prevalent severe diabetic microvascular complications caused by hyperglycemia. Deciphering the underlying mechanism of vascular injury and finding ways to alleviate hyperglycemia induced microvascular complications is of great necessity. In this study, we identified that a compound ent-9α-hydroxy-15-oxo-16-kauren-19-oic acid (EKO), the diterpenoid isolated and purified from Pteris semipinnata L., exhibited good protective roles against vascular endothelial injury associated with diabetic retinopathy in vitro and in vivo. To further uncover the underlying mechanism, we used unbiased transcriptome sequencing analysis and showed substantial impairment in the focal adhesion pathway upon high glucose and IL-1ß stimulation. EKO could effectively improve endothelial focal adhesion pathway by enhancing the expression of two focal adhesion proteins Vinculin and ITGA11. We found that c-fos protein was involved in regulating the expression of Vinculin and ITGA11, a transcription factor component that was downregulated by high glucose and IL-1ß stimulation and recovered by EKO. Mechanically, EKO facilitated the binding of deubiquitylation enzyme ATXN3 to c-fos protein and promoted its deubiquitylation, thereby elevating its protein level to enhance the expression of Vinculin and ITGA11. Besides, EKO effectively suppressed ROS production and restored mitochondrial function. In vivo studies, we confirmed EKO could alleviate some of the indicators of diabetic mice. In addition, protein levels of ATXN3 and focal adhesion Vinculin molecule were also verified in vivo. Collectively, our findings addressed the endothelial protective role of natural diterpenoid EKO, with emphasize of mechanism on ATXN3/c-fos/focal adhesion signaling pathway as well as oxygen stress suppression, implicating its therapeutic potential in alleviating vascular endothelium injury and diabetic retinopathy.

Protura from Hainan Island, China: new species, checklist and distribution.

More than 1500 proturan specimens from Hainan Island are systematically studied. An annotated list of all species of Protura from Hainan Island is provided and their geographical distribution is discussed. The genus Paracondeellum is reported from Hainan Island for the first time, and Paracondeellum paradisum sp. nov. is described. The type species Paracondeellum dukouense (Tang & Yin, 1988) is redescribed based on syntype, and the lectotype and paralectotype are designated. The characters of the genus Paracondeellum are redefined, and the two known species are compared in detail. The Protura fauna of Hainan Island is mainly composed of species from the Oriental region, with 91% of the species belonging to the families Berberentulidae and Eosentomidae.

The mitochondrial genome of Sinentomon erythranum (Arthropoda: Hexapoda: Protura): an example of highly divergent evolution.

BACKGROUND: The phylogenetic position of the Protura, traditionally considered the most basal hexapod group, is disputed because it has many unique morphological characters compared with other hexapods. Although mitochondrial genome information has been used extensively in phylogenetic studies, such information is not available for the Protura. This has impeded phylogenetic studies on this taxon, as well as the evolution of the arthropod mitochondrial genome. RESULTS: In this study, the mitochondrial genome of Sinentomon erythranum was sequenced, as the first proturan species to be reported. The genome contains a number of special features that differ from those of other hexapods and arthropods. As a very small arthropod mitochondrial genome, its 14,491 nucleotides encode 37 typical mitochondrial genes. Compared with other metazoan mtDNA, it has the most biased nucleotide composition with T = 52.4%, an extreme and reversed AT-skew of -0.351 and a GC-skew of 0.350. Two tandemly repeated regions occur in the A+T-rich region, and both could form stable stem-loop structures. Eighteen of the 22 tRNAs are greatly reduced in size with truncated secondary structures. The gene order is novel among available arthropod mitochondrial genomes. Rearrangements have involved in not only small tRNA genes, but also PCGs (protein-coding genes) and ribosome RNA genes. A large block of genes has experienced inversion and another nearby block has been reshuffled, which can be explained by the tandem duplication and random loss model. The most remarkable finding is that trnL2(UUR) is not located between cox1 and cox2 as observed in most hexapod and crustacean groups, but is between rrnL and nad1 as in the ancestral arthropod ground pattern. The "cox1-cox2" pattern was further confirmed in three more representative proturan species. The phylogenetic analyses based on the amino acid sequences of 13 mitochondrial PCGs suggest S. erythranum failed to group with other hexapod groups. CONCLUSIONS: The mitochondrial genome of S. erythranum shows many different features from other hexapod and arthropod mitochondrial genomes. It underwent highly divergent evolution. The "cox1-cox2" pattern probably represents the ancestral state for all proturan mitogenomes, and suggests a long evolutionary history for the Protura.

Molecular phylogeny of Collembola inferred from ribosomal RNA genes.

The classification of taxa within Collembola (Springtails, Hexapoda) has been controversial. In this study, we combined complete 18S rRNA gene with partial 28S rRNA gene (D7-D10) sequences to investigate the phylogeny of Collembola. About 2500 aligned sites of thirty species representing 29 genera from 14 families of Collembola were analyzed, including one species of Neelipleona from which no sequence has been reported previously. The phylogenetic trees were obtained by different methods (maximum parsimony, maximum likelihood, and Bayesian analysis). Our results supported the monophyly of two of the four taxonomic groups of Collembola summarized by Deharveng [Deharveng, L., 2004. Recent advances in Collembola systematics. Pedobiologia 48, 415-433.], namely of Poduromorpha and of Symphypleona. Within Poduromorpha, Neanuridae was monophyletic with high support, but Hypogastruridae was not. Entomobryomorpha was paraphyletic, as the Tomoceroidea (Tomoceridae and Oncopoduridae) was found to be apart from the other entomobryomorphs. In the latter Isotomoidea and Entomobryoidea joined into a group with moderate support. Within Symphypleona, the phylogenetic relationship [(Sminthuridae+Bourletiellidae)+Sminthurididae] was consistent with traditional morphological studies. Neelipleona grouped with Symphypleona in all trees, with moderate support in the ML and Bayesian analyses.

[Effects of vegetation recovery practices on the characteristics of soil nematode communities on seriously degraded grasslands in Songnen Plain].

In this paper, the data of soil nematodes on the seriously degraded grasslands in Songnen Plain under different vegetation recovery practices were collected from May to October, 2005, and the community structure and its seasonal changes of the nematodes were studied by using the community parameters of generic richness, abundance, diversity index, and functional group index. The results showed that both fencing enclosure and planting Puccinellia chinampoensis could improve the nematode communities substantially. The nematode abundance and diversity were significantly higher in planting P. chinampoensis than in fencing enclosure, whereas the generic richness and evenness had no significant difference between these two vegetation recovery practices. The functional group index indicated that fencing enclosure and planting P. chinampoensis altered the ratio of rho- and kappa- choice of plant parasite nematodes. Compared with free-living nematodes, plant parasite nematodes were more sensitive to the vegetation recovery practices. On the seriously degraded grasslands in Songnen Plain, planting P. chinampoensis could be more favorable to the restoration of soil nematode communities than fencing enclosure.

The phylogenetic positions of three Basal-hexapod groups (protura, diplura, and collembola) based on ribosomal RNA gene sequences.

This study combined complete 18S with partial 28S ribosomal RNA gene sequences ( approximately 2,000 nt in total) to investigate the relations of basal hexapods. Ten species of Protura, 12 of Diplura, and 10 of Collembola (representing all subgroups of these three clades) were sequenced, along with 5 true insects and 8 other arthropods, which served as out-groups. Trees were constructed with maximum parsimony, maximum likelihood, Bayesian analysis, and minimum-evolution analysis of LogDet-transformed distances. All methods yielded strong support for a clade of Protura plus Diplura, here named Nonoculata, and for monophyly of the Diplura. Parametric-bootstrapping analysis showed our data to be inconsistent with previous hypotheses (P < 0.01) that joined Protura with Collembola (Ellipura), that said Diplura are sister to true insects or are diphyletic, and that said Collembola are not hexapods. That is, our data are consistent with hexapod monophyly and Collembola grouped weakly with "Protura + Diplura" under most analytical conditions. As a caveat to the above conclusions, the sequences showed nonstationarity of nucleotide frequencies across taxa, so the CG-rich sequences of the diplurans and proturans may have grouped together artifactually; however, the fact that the LogDet method supported this group lessens this possibility. Within the basal hexapod groups, where nucleotide frequencies were stationary, traditional taxonomic subgroups generally were recovered: i.e., within Protura, the Eosentomata and Acerentomata (but Sinentomata was not monophyletic); within Collembola, the Arthropleona, Poduromorpha, and Entomobryomorpha (but Symphypleona was polyphyletic); and in Diplura, the most complete data set (> 2,100 nt) showed monophyly of Campodeoidea and of Japygoidea, and most methods united Projapygoidea with Japygoidea.

[Community structure and seasonal change of soil micro-arthropodes in the Lower Reaches of Liaohe River Plain under different land utilization].

The data on the soil micro-arthropodes under four land utilization types (fallow, forest, upland field and paddy) in the Lower Reaches of Liaohe River Plain were collected in a period from October 2000 to October 2001. Using the community parameters of population density, group richness, diversity index and evenness, the community structure and its seasonal changes were described. There were 12 groups of soil micro-arthropodes in this region, and of the groups, Collembola and Acarina were dominant, and Diptera, Coleoptera and Hymenoptera were often seen in fallow, forest and upland field, while Collembola, Acarina and Diptera were dominant in paddy. Both land utilization and seasonal change influenced the population density, group richness and diversity index of soil micro-arthropodes. The vertical distribution in both density and group number of arthropods in soil was in the order of surface > middle > bottom.

Ribosomal DNA gene and phylogenetic relationships of Diplura and lower hexapods.

The monophyly of Diplura and its phylogenetic relationship with other hexapods are important for understanding the phylogeny of Hexapoda. The complete 18SrRNAgene and partial 28SrRNA gene (D3-D5 region) from 2 dipluran species (Campodeidae and Japygidae), 2 proturan species, 3 collembolan species, and 1 locust species were sequenced. Combining related sequences in GenBank, phylogenetic trees of Hexapoda were constructed by MP method using a crustacean Artemia salina as an outgroup. The results indicated that: (i) the integrated data of 18SrDNA and 28SrDNA could provide better phylogenetic information, which well supported the monophyly of Diplura; (ii) Diplura had a close phylogenetic relationship to Protura with high bootstrap support.

Fine structure of the pyloric region and of the hindgut in the proturan Neocondeellum dolichotarsum (insecta, protura).

The fine structure of the midgut, pyloric region, Malpighian papillae, and hindgut in the proturan, Neocondeellum, was studied. Midgut cells, rich in rough endoplasmic reticulum and mitochondria, are linked to each other by smooth septate junctions. No peritrophic membrane is visible over the microvilli. The posterior cells of the midgut carry short microvilli and are surrounded by a muscular pyloric sphincter. Behind such sphincter is a wide pyloric chamber that has cells with very long microvilli pointing anteriorly toward the midgut. These cells with their microvilli form a kind of stopper that controls the passage of the intestinal content into the hindgut. The Malpighian papillae have an apical globular secretory region producing proteinaceous material, which is then collected in a microvillate cistern at the proximal end of the cell. A peduncle formed by flattened squamous cells joins each papilla to the hindgut epithelium. The hindgut shows two differently organized regions, both engaged in fluid reabsorption. The principal cells of the anterior region show a system of apical subcuticular cavities into which thin microvilli extend. In the cytoplasm of these cells, there are numerous mitochondria associated with infoldings of the plasma membrane. The principal cells of the posterior hindgut region have bundles of long microvilli beneath the cuticle. Also, these cells exhibit at their base an abundant system of infoldings of the plasma membrane and mitochondria. The results are considered in relation to the phylogenetic relationship between Neocondeellum and other proturan genera.