Identification of differentially expressed genes during the brachyurization of the Chinese mitten crab Eriocheir japonica sinensis.

Expressed sequence tags (ESTs) obtained from two-directional suppression subtractive hybridization (SSH) of cDNA libraries derived from the pleon of the Chinese mitten crab were analyzed using mRNA subtractive hybridization. After cDNA cloning and sequencing, gene expression profiles were examined, focusing on brachyurization. We assembled 211 non-redundant ESTs from SSH library 1 (yielding 130 unique transcripts: 25 consensi, 105 singletons) and 669 from SSH library 2 (195: 51 consensi, 144 singletons). Functional analysis shows that these genes are putatively involved in various cellular processes (33%), ribosomal RNA/proteins (30%), molting (12%), signal transduction (6%), immune factor and stress proteins (6%), development (4%), energy metabolism (3%), and mitochondrial membrane protein, hormone metabolizing, and chaperone (1% each) of other organisms. Some 3% are of unknown function in SSH library 1. The results facilitate the functional study of candidate genes involved in early developmental processes, especially the regulation of brachyurization in this crab.

Identification, mRNA expression and characterization of proliferating cell nuclear antigen gene from Chinese mitten crab Eriocheir japonica sinensis.

The sliding clamp proliferating cell nuclear antigen (PCNA) plays important roles in nucleic acid metabolism. In this work, we isolated a PCNA gene (designated as EjsPCNA, accession: FJ483830) by rapid amplification of cDNA ends approach from the Chinese mitten crab Eriocheir japonica sinensis. The full-length cDNA of EjsPCNA consists of 1123 nucleotides with an open-reading frame of 780bp encoding 259 amino acids (28.62kDa) and containing an interdomain connecting loop, C-terminal tail, and center loop. Sequence alignment, phylogenetic analyses, and structure comparison revealed that EjsPCNA is a member of the PCNA family. Real-time RT-PCR results indicate that EjsPCNA is expressed throughout three developmental stages. EjsPCNA mRNA expression levels at the first crab stage are significantly higher than that of the other two stages. Present data showed that the expression levels of EjsPCNA in E. j. sinensis are likely related to proliferation activity of tissues, and suggested that EjsPCNA gene is probably involved in the crabs' early developmental regulation.

Identification, mRNA expression and characterization of a novel ANK-like gene from Chinese mitten crab Eriocheir japonica sinensis.

Ankyrins are a family of adapter molecules mediating linkages between integral membrane and cytoskeletal proteins. Ankyrin repeat is one of the most frequently observed amino acid motifs in protein databases. A novel ANK-like gene of Chinese mitten crab Eriocheir japonica sinensis (denoted as EjsANK) was identified and cloned by expressed sequence tag and rapid amplification of cDNA end approaches. The full-length cDNA of EjsANK is 4375 bp and contains an open reading frame of 1095 bp which encodes a 364 amino acids polypeptide (40.23 kD) bearing seven ankyrin repeats. EjsANK cDNA has a 3073 bp uniquely long 3' untranslated region with three K-box elements, one GY-like box domain and one Brd-like box domain. Sequence alignment and three-dimensional structural analyses revealed that EjsANK should be a novel cytosolic member of the ankyrin family. Fluorescent real-time quantitative RT-PCR approach was performed to examine the expression profiles of EjsANK mRNA by testing its relative level in three types of tissues at three different developmental stages, respectively. We found that the relative level of EjsANK mRNA expression was significantly higher in the abdomen at the first crab stage. Functional bioinformatics prediction analyses indicated that EjsANK has an analogical effect like IkappaB which is a key component of IkappaB/NF-kappaB complex in mammalian cells playing very important roles in the development process. Results suggest that EjsANK gene is involved in the early developmental regulation of Chinese mitten crab, especially brachyurization regulation.

Molecular cloning, mRNA expression, and characterization of HSP90 gene from Chinese mitten crab Eriocheir japonica sinensis.

HSP90 is a highly conserved molecular chaperone important in the maturation of a broad spectrum of proteins. Using expressed sequence tag (EST) and rapid amplification of cDNA ends (RACE) techniques, an HSP90 gene designated as EjsHSP90 was cloned and characterized from the Chinese mitten crab Eriocheir japonica sinensis. The full-length cDNA of EjsHSP90 is 2,517 bp and contains an open reading frame of 2157 bp which encodes a 718 amino acid polypeptide (82.8 kDa) bearing characteristics of the HSP90 family and an ATP binding domain. Sequence alignment shows that EjsHSP90 shared 79%-96% identity with HSP90 sequences reported in other animals, and it shares identical structural features. Fluorescent real-time quantitative RT-PCR approach was performed to examine the expression profiles of EjsHSP90 mRNA by testing its relative level in three types of tissues at three different developmental stages, respectively. We found that EjsHSP90 is expressed throughout the three developmental stages but expression levels varied among different body parts of crabs. EjsHSP90 mRNA expression in the abdomen of the first crab stage is consistently higher than that of the other two stages, suggesting that EjsHSP90 gene is involved in the crabs' early developmental process, especially in the crab brachyurization process. Results from quantitative RT-PCR excluded the possibility that the expression of EjsHSP90 mRNA is induced primarily by osmotic stress. Phylogenetic analyses reveal that HSP90 gene is informative and complementary for reconstruction of arthropod phylogenetic relationships.

The complete mitochondrial genome of Symphylella sp. (Myriapoda: Symphyla): Extensive gene order rearrangement and evidence in favor of Progoneata.

We determined the complete 14,667bp mitochondrial DNA sequence of Symphylella sp., the first representative of the Scolopendrellidae (Arthropoda: Myriapoda: Symphyla). With respect to the ancestral arthropod mitochondrial gene order, two protein-coding genes, the rRNAs and 10 of the tRNAs appear to be rearranged. This rearrangement is novel in the arthropods and genes with identical transcriptional polarity are clustered except for trnE, trnN and putative control region (CR), resembling two previously reported diplopod genomes. A duplication/loss (random and non-random)-recombination model was proposed to account for the generation of the gene order in Symphylella sp. All phylogenetic analysis yielded strong support for a clade of Symphyla plus Diplopoda, i.e., Progoneata. However, the phylogenetic position of Myriapoda within Arthropoda remains unclear. The amino acid dataset gives strong support for an affinity to Pancrustacea, while the nucleotide dataset weakly supports Myriapoda grouped with Chelicerata.

The complete mitochondrial genome of Parafronurus youi (Insecta: Ephemeroptera) and phylogenetic position of the Ephemeroptera.

The first complete mitochondrial genome of a mayfly, Parafronurus youi (Arthropoda: Insecta: Pterygota: Ephemeroptera: Heptageniidae), was sequenced using a long PCR-based approach. The genome is a circular molecule of 15,481 bp in length, and encodes the set of 38 genes. Among them, 37 genes are found in other conservative insect mitochondrial genomes, and the 38(th) unique gene is trnM-like (trnM2). The duplication-random loss model can be used to explain one of the translocations at least. The A+T content of the control region is 57%, the lowest proportion detected so far in Hexapoda. Based on the nucleotide dataset and the corresponding amino acid dataset of 12 protein-coding genes, Bayesian inference and maximum likelihood analyses yielded stable support for the relationship of the three basal clades of winged insects as Ephemeroptera+(Odonata+Neoptera).

[Antibacterial activity of water soluble fraction from Scolopendra subspinipes mutilans].

The water soluble fraction (SWSF) of centipede Scolopendra subspinipes mautilans, injected with Escherichia coli K12 D31 for 3-4 days showed broad-spectrum antimicrobial activity against Gram-positive, Gram-negative bacteria and fungi. It showed strong antibacterial activity against E. coli K12D31 at different temperatures, pH and ionic strengths. It did not show any hemolytic and agglutination activities at the concentration below 600 microg/ml. After E. coli K12 D31 treated with SWSF, the ultrastructure showed that its outer cell wall was broken, surface collapsed and intracellular substances leaked out.

[Cloning and prokaryotic expression of major ampullate spidroin gene of spider].

RT-PCR was conducted with one degenerate primer designed according to repetitive regions' amino acid sequence of major ampullate spidroin (MaSp) in spiders and adaptor primer in the SMART cDNA Library Construction Kit. By cloning and sequencing of amplified products, one cDNA clone (GenBank Accession No. AY365017) of Argiope amoena MaSp gene was obtained. The deduced amino acid sequence can be distinctly divided into two regions: (1) Repetitive region that consists of an alternating alanine-rich and glycine-rich domain in which many prolines are present; and (2) C-terminal non-repetitive region. The region coding for 272 amino acids of MaSp gene was subcloned into prokaryotic expression vector pET28b(+) and an about 26kD recombinant protein was expressed at high levels in Escherichia coli BL21 (DE3) after induction of IPTG. After being purified with metal-affinity chromatography on Ni(2+) -IDA-Sepharose columns as well as gel filtration chromatography, the recombinant protein was confirmed to be predicted MaSp by means of amino acid composition analysis and N-terminal amino acid sequence analysis. The solubility behavior of recombinant MaSp with C-terminal non-repetitive region in the present study is similar to that of recombinant dragline silk proteins without C-terminal non-repetitive region expressed by bacteria and yeast in the other studies. The result shows that absence or presence of C-terminal non-repetitive region is not a crucial factor affecting the solubility of the recombinant MaSp.

Incongruous nuclear and mitochondrial phylogeographic patterns in two sympatric lineages of the wolf spider Pardosa astrigera (Araneae: Lycosidae) from China.

We investigated the genetic structure of mitochondrial DNA (COI and 16S rRNA-tRNA(Leu(CUN))-ND1) and nuclear DNA (ITS2) variations among and within populations of Pardosa astrigera in China. Two phenotypes of males were recognized. They differed genetically also in the presence (type A) or absence (type B) of common insertions and deletions in ITS2. The concordance between mtDNA based phylogeny and the phenotypic variations of P. astrigera was weak. Haplotypes of type A did not form a monophyletic group. Instead they were found in three clades, in one of them mixed with type B haplotypes, most likely as a result of long-term and ongoing gene flow of mtDNA between the two phenotypic groups (M = 0.69). Pairwise sequence divergences of all data sets indicated that the genetic divergences between the two phenotypes fall within intraspecific range. Our results indicated that the P. astrigera populations in China consist of two sympatric lineages with male phenotypic variations. Patterns of mismatch distribution within lineages suggested long-term demographic stability in the lineage A, and growth in lineage B that expanded rapidly and recolonized from a southern refuge to the northern parts of China during the late-Pleistocene. On the basis of the estimated divergence time between the two lineages (0.18-0.41 Ma), we suggest that the dry-cold climate and the uplift of the Tibetan plateau during the mid-Pleistocene appear to have a determinating impact on the evolutionary history of P. astrigera in China.

Myriapod monophyly and relationships among myriapod classes based on nearly complete 28S and 18S rDNA sequences.

Myriapods play a pivotal position in the arthropod phylogenetic tree. The monophyly of Myriapoda and its internal relationships have been difficult to resolve. This study combined nearly complete 28S and 18S ribosomal RNA gene sequences (3,826 nt in total) to estimate the phylogenetic position of Myriapoda and phylogenetic relationships among four myriapod classes. Our data set consists of six new myriapod sequences and homologous sequences for 18 additional species available in GenBank. Among the six new myriapod sequences, those of the one pauropod and two symphylans are very important additions because they were such difficult taxa to classify in past molecular-phylogenetic studies. Phylogenetic trees were constructed with maximum parsimony, maximum likelihood, and Bayesian analyses. All methods yielded moderate to strong support for the monophyly of Myriapoda. Symphyla grouped strongly with Pauropoda under all analytical conditions. The KH test rejected the traditional view of Dignatha and Progoneata, and the topology obtained here, though not significantly supported, was Diplopoda versus ((Symphyla + Pauropoda) + Chilopoda).

Pharmacological characterisation of spider antimicrobial peptides.

Most spider antimicrobial peptides share a common mechanism of membrane permeabilisation and the innate immune systems of the pathogen. In this review, we present recent accounts of the application at the preclinical level that should be tried and the range of bioactivities and their particular structure can be harnessed for molecular engineering applications and in drug design. Structural analyses such as amino acid sequence and circular dichroism are described. Conductance measurements and pharmacological studies of the action on the inner or outer membranes of anti-microbe will reveal more about the mode of action of the antimicrobial peptides of spider.

Mitochondrial genome of the Chinese mitten crab Eriocheir japonica sinenesis (Brachyura: Thoracotremata: Grapsoidea) reveals a novel gene order and two target regions of gene rearrangements.

We determined the complete 16,354 bp mitochondrial DNA sequence of the Chinese mitten crab Eriocheir japonica sinesnesis. It consists of 13 protein coding genes (PCGs), 2 rRNAs, and 22 tRNAs, typical of metazoan mitochondrial genomes. With respect to the ancestral crustacean mt gene order, a PCG, the rRNAs, and 12 of the tRNAs appear to be rearranged. This rearrangement is novel in the arthropods and suggests an accelerated rate of mt genome rearrangement in this brachyuran lineage based on the relative rate of gene rearrangement. It is typical in arthropods that all of the rearranged genes or gene blocks take place at both nad3-nad5 and nad5-nad4 gene junctions. Such occurrence additionally revealed two target regions of frequent rearrangement in mitochondrial genomes of decapods, even in that of the non-hexapod arthropods according to our comparative studies among 32 taxa. Additionally, selective constraint on sharing the single introducing location is apparent for most of the rearrangements that occurred at the nad3-nad5 gene junction of these taxa. The gene arrangement features at both gene junctions allow the reconstruction of relationships among the advanced decapods. These features are therefore characteristic molecular markers in phylogenetic inference. The genomic organization differences at both gene junctions provide new evidence of extremely divergence between Heterotremata and Thoracotremata in brachyuran crabs. A duplication/loss (random and nonrandom)-recombination model was proposed to account for the generation of the gene order in E. japonica sinesnesis under the guide of intergenic spacers.

The mitochondrial sequences of Heptathela hangzhouensis and Ornithoctonus huwena reveal unique gene arrangements and atypical tRNAs.

We have sequenced the complete mitochondrial genomes of the spiders Heptathela hangzhouensis and Ornithoctonus huwena. Both genomes encode 13 protein-coding genes, 22 tRNA genes, and 2 ribosomal RNA genes. H. hangzhouensis, a species of the suborder Mesothelae and a representative of the most basal clade of Araneae, possesses a gene order identical to that of Limulus polyphemus of Xiphosura. On the other hand, O. huwena, a representative of suborder Opisthothelae, infraorder Mygalomorphae, was found to have seven tRNA genes positioned differently from those of Limulus. The rrnL-trnL1-nad1 arrangement shared by the araneomorph families Salticidae, Nesticidae, and Linyphiidae and the mygalomorph family Theraphosidae is a putative synapomorphy joining the mygalomorph with the araneomorph. Between the two species examined, base compositions also differ significantly. The lengths of most protein-coding genes in H. hangzhouensis and O. huwena mtDNA are either identical to or slightly shorter than their Limulus counterparts. Usage of initiation and termination codons in these protein-coding genes seems to follow patterns conserved among most arthropod and some other metazoan mitochondrial genomes. The sequences of the 3' ends of rrnS and rrnL in the two species are similar to those reported for Limulus, and the entire genes are shortened by about 100-250 nucleotides with respect to Limulus. The lengths of most tRNA genes from the two species are distinctly shorter than those of Limulus and the sequences reveal unusual inferred tRNA secondary structures. Our finding provides new molecular evidence supporting that the suborder Mesothelae is basal to opisthothelids.

Effects of spider Macrothele raven venom on cell proliferation and cytotoxicity in HeLa cells.

AIM: To examine the effect of venom from the spider Macrothele raven on cell proliferation and cytotoxicity in human cervical carcinoma, HeLa cells. METHODS: Morphological and biochemical signs of apoptosis appeared using acridine orange-ethidium bromide (AO/EB) staining. Marked morphological changes in HeLa cells after treatment with spider venom were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Cell proliferation and cytotoxicity were determined by [methyl-3H] thymidine assay ([3H]TdR) and lactate dehydrogenase (LDH) release, respectively. DNA fragmentation and cell cycle distribution were monitored using flow cytometry. In addition, Western blot analysis was used to evaluate the level of caspase-3 expression. In vivo examination of the inhibition of the size of tumors in nude mice treated with spider venom was measured. RESULTS: Marked morphological changes were observed using AO/EB staining, SEM and TEM assay. Spider venom at concentrations of 10-40 mg/L caused dose- and time-dependent inhibition of HeLa cell proliferation. The ratio of apoptosis and necrosis increased. The activity of caspase-3 was upregulated after spider venom treatment. In vivo study of tumor size revealed that tumors significantly decreased in size from controls to tumors treated for 3 weeks with spider venom (P<0.05). CONCLUSION: The inhibition of HeLa cells by the venom of the spider Macrothele raveni was carried out in three ways: induction of apoptosis, necrosis of toxicity damage and direct lysis. Spider venom is a novel anti-tumor material both in vitro and in vivo.

Phylogenetic placement of the spider genus Nephila (Araneae: Araneoidea) inferred from rRNA and MaSp1 gene sequences.

The family status of the genus Nephila, which belongs to Tetragnathidae currently but Araneidae formerly, was reexamined based on molecular phylogenetic analyses. In the present study, 12S and 18S rRNA gene fragments of eight species of spiders were amplified and sequenced. In addition, 3'-end partial cDNA of major ampullate spidroin-1 (MaSp1) gene of Argiope amoena was cloned and sequenced, and the 3'-end non-repetitive region's cDNA sequence of MaSp1 gene and the predicted amino acid sequence of C-terminal non-repetitive region of MaSp1 were aligned with some previously known sequences. The resulting phylogeny showed that Araneidae and Tetragnathidae are not a sister group in the superfamily Araneoidea, and the genus Nephila is closer to the genera of the family Araneidae rather than to those of Tetragnathidae. We suggest that the genus Nephila should be transferred back to Araneidae. Or the subfamily Nephilinae might be elevated to family level after it was redefined and redelimited. Furthermore, the study showed that 3'-end non-repetitive region's cDNA sequence of MaSp1 gene and C-terminal non-repetitive region's amino acid sequence of MaSp1 are useful molecular markers for phylogenetic analysis of spiders.

Molecular systematics of the Asian mitten crabs, genus Eriocheir (Crustacea: Brachyura).

To help resolve phylogenetic relationships among the mitten crabs, complete sequences of the nuclear DNA internal transcribed spacer (ITS) and portions of the mitochondrial genome corresponding to the cytochrome oxidase I (COI), were sequenced for all Asian mitten crabs of the genus Eriocheir and seven species of the Grapsoidea. The resulting phylogeny supports the establishment of a separate genus Neoeriocheir, but does not provide justification for the recognition of Platyeriocheir. A female mitten crab specimen from the Zhujiang River, China, was considered to be Eriocheir recta (), a species previously synonymized with Eriocheir japonica (de Haan, 1835). In the ITS analysis, a sequence from Eriocheir formosa (from Taiwan) falls within a well-supported E. recta group, which indicates that E. formosa may have to be synonymized with E. recta. Three previously recognized members of the genus, E. japonica, Eriocheir sinensis, and Eriocheir hepuensis constitute a monophyletic sister group to E. recta in all phylogenetic trees. We provide evidence for the conspecific status of these taxa. Phylogenetic trees based on COI and combined COI and ITS sequences indicate that E. japonica consists of three subgroups. Since the name E. japonica (de Haan, 1835) takes precedence over E. sinensis (H. Milne Edwards, 1853) and E. hepuensis, we suggest that these three subgroups correspond to three subspecies of E. japonica: E. j. japonica, E. j. sinensis, and E. j. hepuensis.