Construction of a cDNA library for Sparganum mansoni and screening of diagnostic antigen cadidates / 中国血吸虫病防治杂志

Objective To construct a cDNA library of Sparganum mansoni and immunoscreen antigen candidates for immunodiagnosis of sparganosis mansoni. Methods Total RNA was extracted from S. mansoni, and reversely transcribed into cDNA, which was ligated into the phage vector. These recombinant vectors were packaged in vitro to construct the SMART cDNA library of S. mansoni. Then, the cDNA library was immunoscreened with sera from patients with sparganosis mansoni to yield positive clones. The inserted fragments of positive clones were sequenced and subjected to homology analyses, and the structure and functions of the coding proteins were predicted. Results The SMATR cDNA library of S. mansoni was successfully constructed. The titer of the cDNA library was 6.25 × 106 pfu/mL, with a recombinant efficiency of 100%, and the mean length of the inserted fragments in the library was larger than 1 100 bp. A total of 12 positive clones were obtained by immunoscreening, and were categorized into Sm-I (Sm60-1), Sm-II (Sm58-1), Sm-III (Sm20-1) and Sm-IV (Sm22-3), with 1 134, 1 063, 883 bp and 969 bp long inserted fragments. Their coding proteins were highly homologous with the Spirometra erinaceieuropaei antigenic polypeptide, cytoplasmic antigen, ribosomal protein S4-like protein and unnamed protein product, respectively. Conclusions A SMART cDNA library of S. mansoni has been successfully constructed and 4 categories of positive clones have been identified, which provides a basis for further studies on diagnostic antigens for sparganosis mansoni.

cDNA cloning of a novel lectin that induce cell apoptosis from Artocarpus hypargyreus / 中国天然药物

We isolated a novel lectin (AHL) from Artocarpus hypargyreusHance and showed its immunomodulatory activities. In this study, the amino acid sequence of AHL was determined by cDNA sequencing. AHL cDNA (875bp) contains a 456-bp open reading frame (ORF), which encodes a protein with 151 amino acids. AHL is a new member of jacalin-related lectin family (JRLs), which share high sequence similarities to KM+ and Morniga M, and contain the conserved carbohydrate binding domains. The antitumor activity of AHL was also explored using Jurkat T cell lines. AHL exhibits a strong binding affinity to cell membrane, which can be effectively inhibited by methyl-α-D-galactose. AHL inhibits cell proliferation in a time- and dose-dependent manner through apoptosis, evidenced by morphological changes, phosphatidylserine externalization, poly ADP-ribose polymerase (PARP) cleavage, Bad and Bax up-regulation, and caspase-3 activation. We further showed that the activation of ERK and p38 signaling pathways is involved for the pro-apoptotic effect of AHL.

Gene cloning, heterologous expression and activity identification of latroeggtoxin-Ⅵ / 生物工程学报

One of the distinct characters of Latrodectus tredecimguttatus is that its toxic components exist not only in the venomous glands, but also in the tissues outside the venomous glands and even in the eggs. Investigation on the toxins outside the venomous glands can deepen our understanding of spider toxins and discover new lead molecules with important application prospects. In order to explore the low-abundance proteinaceous toxins in the L. tredecimguttatus eggs, we used bioinformatic strategies to mine a gene sequence encoding a peptide toxin from the transcriptome of L. tredecimguttatus eggs, and then heterologously expressed the gene successfully with a 3'-RACE combined with nest PCR strategy. Biological activity analyses indicated that the expressed peptide toxin, named latroeggtoxin-Ⅵ (LETX-Ⅵ), could inhibit Na⁺ channel currents in ND7/23 cells and promote dopamine release from PC12 cells, without obvious toxicity against Periplaneta americana and bacteria as well as fungi including Staphylococcus aureus and Candida albicans, demonstrating that LETX-Ⅵ is a mammal-specific neurotoxin with a potential application prospect in development of the tool reagents for neurobiological study and the drugs for treating related diseases.

An easy and robust method for the isolation of high quality RNA from coconut tissues

BACKGROUND: Coconut tissues consist of a complex network of polysaccharides, proteins, polyphenols, and lipids that can bind to nucleic acids and pose difficulty in isolation. Certainly, a vigorous method is required to isolate high quality and quantity of RNA from such tissues for the purpose of downstream experiments. In this paper, we discuss a newly developed method for the Isolation of RNA from Complex Matrices (IRCM) method from coconut tissues. RESULTS: The method is robust, cheap, and efficient for the extraction of quality RNA in high quantities from the solid endosperm of stored and fresh coconut (150 µg/g FW with A260/280 = 1.89 and 247.5 µg/g FW with A260/280 = 1.91), coconut apple (263.8 µg/g FW with A260/280 = 1.97), and coconut bud (1052.5 µg/g FW with A260/280 = 2.00). The other well established methods, such as Method of RNA Isolation from Palm (MRIP), Cetyl Trimethyl Ammonium Bromide (CTAB), TRIZOL, and RNA plant kit failed to isolate quality RNA in appreciable quantities from the coconut tissues. Furthermore, the resultant RNA performed well in the downstream experiment, that is, RT-PCR for the production and amplification of cDNA. CONCLUSIONS: From the study, we concluded that the present method will play a vital role in the extraction of high quality RNA from complex matrices in a short time.

Restoration of the inflammatory gene expression by horse oil in DNCB-treated mice skin

Construction of full-length cDNA library from Antrodia cinnamomea mycelium and EST sequence analysis / 中草药

Objective: To excavate the terpenoid synthesis and metabolism-related gene function and screen the interaction protein and fingerprint analysis of Antrodia cinnamomea mycelium, a cDNA library from A. cinnamomea mycelia was constructed and the EST sequences were analyzed. Methods: The cDNA library from the A. cinnamomea mycelium was constructed by the Gateway technique. A part of EST sequences about the bioinformatics, functional annotation and EST-SSR were analyzed. Results: The cDNA library of the A. cinnamomea mycelium was constructed successfully. The recombinant rate of the cDNA library was 95%, the titer of the library was 6.1 × 106 cfu/mL, the total cloning number was 1.2 × 107 cfu, the length of cDNA was between 300-2 000 bp with an average length of 1 000 bp. The clones were randomly sequenced and 65 valid ESTs were obtained. After being compared in the Genbank database, 45 ESTs had a definite annotation, and 18 ESTs were unnamed and hypothetical protein. The results with GO functional annotation showed that the ESTs involved the cell composition, transport, catalytic activity, regulation functions and etc. It contained 271 SSRs of all the ESTs in total. The nucleotide repeats in A. cinnamomea were abundant, among which dinucleotide and trinucleotide repeat units were more common accounting for 94.23%. Conclusion: The cDNA library from the A. cinnamomea mycelium and its ESTs related biological information were preliminarily identified, which will provide a theoretical foundation for research the mycelium genomics of A. cinnamomea.

Obtaining vacuolar protein sorting 34 gene in Sporothrix globosa by RACE method and analysis of its expression during the mycelium-to-yeast transition / 中华微生物学和免疫学杂志

Objective To obtain the full-length sequence of the vacuolar protein sorting 34 coding gene (vps34) of Sporothrix globosa (S. globosa) and to investigate the role of vps34 gene during the phase transition from mycelium to yeast in S. globosa. -ethods The 3′ end and 5′ end of the vps34 gene of S. globosa were amplified by rapid amplification of cDNA ends ( RACE ) . The obtained sequences were spliced and analyzed by bioinformatics software. Quantitative reverse transcription PCR ( qRT-PCR ) was used to analyze the expression of vps34 gene in mycelial and yeast phases. Results The vps34 gene of S. globosa was 3228 bp in length. The coding sequence was 3000 bp and encoded 999 amino acids with a mo-lecular mass of 111. 49×103 and an isoelectric point of 6. 38. It contained three domains including C2 PI3K class Ⅲ, PI3Ka Ⅲ and PI3Kc Ⅲ. The results of qRT-PCR showed that the expression of vps34 gene in yeast-phase S. globosa was higher than that in mycelial phase at 24 h (P<0. 05), and the greatest difference between them was observed at 48 h (P<0. 01). Conclusions Vps34p participates in the process of dimor-phic transformation of S. globosa. The obtainment of the full-length vps34 gene of S. globosa lays the founda-tions for further study on the function of Vps34p.

Full-length Cloning and Protein Expression Analysis of Glycosyltransferases Gene SaUGT1/SaUGT2 in Sorbus aucuparia / 中国实验方剂学杂志

Objective: To obtain the glycosyltransferase gene involved in modification reaction of phytoalexin from Sorbus pohuashanensis suspension cell,and conduct sequence analysis and prokaryotic expression analysis. Method: Based on the transcriptome data,specific primers were designed to obtain 2 cDNA sequences of SaUGTs genes,construct prokaryotic expression vector HIS-MBP-pET28a-SaUGTs and induce the expression of recombinant SaUGTs protein. Result: SaUGT1 and SaUGT2 sequences were cloned and obtained from glycosyltransferases,then bioinformatic analysis of the sequence and prokaryotic expression analysis were conducted. SaUGT1 gene contained 1 458 bp open reading frame (ORF),encoding a polypeptide of 485 amino acids,with a relative molecular weight of 54.27 kDa and theoretical isoelectric point (pI) of 5.50.SaUGT2 gene contained 1 431 bp ORF,encoding a polypeptide of 476 amino acids,with a relative molecular weight of 53.49 kDa and theoretical pI of 5.63. Bioinformatics analysis indicated that SaUGT1 and SaUGT2 protein had no signal peptide,and the conserved domains of glycosyltransferase family were detected. Phylogenetic results showed that SaUGT1 and SaUGT2 proteins had the closest relationship with the UGT85 family of A. thaliana. Differential expression analysis revealed that the relative expression levels of SaUGT1 and SaUGT2 were increased significantly after being induced by yeast extract (YE), with the highest expression level found at 24 h and 12 h. The recombinant SaUGT1 and SaUGT2 proteins were successfully expressed in Escherichia coli DE3 cells and finally,the recombinant SaUGT1 and SaUGT2 proteins were purified through Ni2+ affinity chromatography. Conclusion: The glycosyltransferase gene was cloned from the S. aucuparia for the first time,and the prokaryotic expression vector was successfully constructed,laying foundation for further study of the function of this gene.

Construction of human promyelocytic cDNA library and its identification / 吉林大学学报(医学版)

Objective: To construct a cDNA library of human promyelocytic leukemia (HL60), and to elucidate the mechanism of related genes in the pathogenesis and development of acute promyelocytic leukemia (APL). Methods: The total RNA of HL60 cells was extracted by Trizol method. The mRNA of samples were isolated and purified by centrifugal column method. The first strand of the cDNA was synthesized by reverse transcriptase-polymerase chain reaction (RT-PCR) while the second strand was synthesized by enzyme-catalyzed method. The cDNA fragments were recovered and then linked to the pPR3-N vector. The human promyelocytic cDNA library was constructed by homologous recombination in yeast strain Y187. The culture fluid was coated with LB plate to identify the library capacity, and PCR method was used to identify the size and distribution of the inserted fragment. Results: The RNA strand extracted from HL60 cells was clear, non-degradable and had low dispersion. The purified cell mRNA was used as template to synthesize the cDNA. After recovering the cDNA fragments, the cDNA fragments were successfully linked to the pPR3-N vector. The recombinant vector was transformed into yeast strain Y187, and the human promyelocytic cDNA library was successfully constructed by homologous recombination. The original electro transformation bacteria were diluted 100 times and 10 μL coating plate was taken, about 250 clones were generated. The total library capacity was 2. 5 × 106 CFU mL-1 and the total library capacity was 1. 25 × 107 CFU for 5 mL of transformed original bacterial solution. The average insertion fragment was more than 1 200 bp, and the positive rate was 100%. Conclusion: The human promyelocyic cDNA library is successfully constructed, and it lays a foundation for studying the pathogenesis and therapeutic mechanism of leukemia.

Full-length cDNA cloning of AsJAZ1 gene and damage-induced expression analysis in Aquilaria sinensis callus / 中草药

Objective: To clone the full-length cDNA of jasmonate-zim-domain protein (JAZ) gene in Aquilaria sinensis to provide the basic information for further study on gene function in sesquiterpenes biosynthesis pathway. Methods: With the total RNA as template, the full-length cDNA of JAZ in A. sinensis was cloned through rapid amplification of cDNA ends (RACE) technique and reverse transcription PCR (qRT-PCR) method. The bioinformatics of the JAZ gene was analyzed as well. The expression of this gene was detected by qRT-PCR method with MeJA and mechanical wounding treatment in A. sinensis callus. Results: The full-length cDNA (1 507 bp) of JAZ gene was named AsJAZ1; GenBank registration number was KP677281. AsJAZ1 was obtained with an open reading frame (ORF) of 990 bp and encoding 330 amino acids. The relative molecular mass of AsJAZ1 calculated was 34 280, and the isoelecric point was 6.89. Real time PCR results indicated that both MeJA treatment and mechanical wounding could stimulate the increase of mRNA expression of AsJAZ1; There was a sharp rise at 0.5 h with about 27 times higher than the control (without MeJA treatment) with MeJA treatment, then dropped significantly. In mechanical wounding treatment, the highest peak presented in 2 h about 17 times compared to the control, then dropped significantly too. The expression of AsJAZ1 gene returned to be normal in 24 h. Conclusion: We have obtained the full-length cDNA sequence of AsJAZ1 gene firstly, which was extremely sensitive to wounding and responded to the early damage.

Analysis of a patient with early-onset Parkinson’s disease and PARK7 gene variation / 中华医学遗传学杂志

Objective@#To explore the genetic basis of a patient with early-onset Parkinson disease from a consanguineous family.@*Methods@#Homozygosity mapping and Sanger sequencing of cDNA were used to identify the causative mutation.@*Results@#A homozygous missense variation (c.56C>G, p. Thr19Arg) in the PARK7 gene was identified in the patient. In silico analysis suggested the c. 56C>G variation to be pathogenic.@*Conclusion@#Homozygous c. 56C>G variation of the PARK7 gene was the disease-causing variation in this family.

Construction of Yeast Two-Hybrid Vectors for Screening Novel OTULIN-, OTUB1- and OTUB2-Interacting Protein from Human cDNA Library

@#Introduction: OTULIN, OTUB1 and OTUB2 are deubiquitinases, the enzymes responsible for reversing ubiquitination process that occupies key roles in numerous cellular processes. The ubiquitination protein-protein interaction (PPI) network has been extensively explored in order to unravel the complexity of ubiquitin pathway. However, many significant challenges remain to develop a network-based understanding of the ubiquitination complexity including incompleteness of human interactome. Therefore, we aim to construct a pair of yeast two-hybrid (Y2H) vectors using pDEST32/pDEST22 vector system as a preparation for screening OTULIN-, OTUB1- and OTUB2-interacting proteins from human cDNA library, with ultimate aim of expanding the PPI network in human ubiquitome. Methods: OTULIN, OTUB1 and OTUB2 were cloned into entry vector using pCR™8/GW/TOPO® TA Cloning® system and shuttled into pDEST™32 bait vector by LR recombination reaction. To generate Y2H prey library clones, cDNA library was synthesized from HEK293 cells and cloned into donor vector pDONR™222 before transferred into destination vector pDEST™22. Results: DNA sequencing analysis confirmed the correct sequence of OTULIN, OTUB1 and OTUB2 inserts in pDEST32. Meanwhile, generation of cDNA library in pDEST22 produced 5.2 x 106 clones. Randomly picked pDEST22-cDNA clones showed that the recombination rate was 83% and gel electrophoresis indicated that the inserts length ranged from 0.45 to 3.4 kb. Conclusion: OTULIN, OTUB1, OTUB2 and cDNA library were successfully cloned into Y2H bait and prey vectors. The clones have been transfected into competent yeast Saccharomyces cerevisiae strain MaV203 and Y2H experiment to screen novel OTULIN-, OTUB1- and OTUB2-interacting protein from human cDNA library is underway.

Investigation of Differential Genes Expression in the Genome of Epipactis flava Seidenf. (Orchidaceae) under Flooded Condition Using cDNA-SRAP Analysis

Epipactis flava Seidenf. is classified into a rare type of orchid species, a rheophyte. The specific habitat for its life cycle requires a strong current and flooding time. In this study, differential gene expression between submerged and non-submerged conditions was studied using the cDNA-SRAP method. RNAs were extracted from rhizomes at 0, 6, 12, 24 and 48 hours after submergence. Seven candidate genes were selected to study the relative gene expression by real-time RT-PCR and found to be upregulated in submergence condition. Six of these, RNA polymerase sigma factor gene, ATPase gene, Plant homeodomain finger Alfin-like genes, DNA-3-methyladenine glycosylase gene, and Allene oxide synthase gene were induced to the highest level within 12 hrs. Subsequently, the expression of five genes decreased at 24 and 48 hrs of treatment except for UDP-glucosyl transferase gene which showed stable expression at all time. Apart from others, dolichyl-diphosphooligosaccharide glycosyl transferase gene was induced to the highest level at 24 hrs and was stable until 48 hrs. This suggested that the induction of genes expression by flooding occurred within 12-24 hrs and most genes in this finding involved in stress responses which were easily upregulated in rheophytic plants during submergence. The more differentially expressed genes should be analysed for a further understanding of the rheophytic habit of this plant.

Molecular cloning of troponin i from the two-spotted cricket, Gryllus bimaculatus, and its expression pattern during starvation / Clonagem molecular da Troponina I do grilo africano, Gryllus bimaculatus, e seu padrão de expressão durante a inanição

There is few information about troponin gene expression by starvation in insect skeletal muscle and digestive tracts. The objective of this study was to perform molecular cloning of troponin I from the two-spotted cricket, Gryllus bimaculatus (GrybiTnI) and determine its expression patterns in three different skeletal muscles and digestive tracts during starvation. GrybiTnI was translated into a protein encoding 198 amino acids with a theoretical isoelectric point of 9.78 and a molecular weight of 23671.46 Da. The GrybiTnI has both the TnC-binding site and actin/TnC-binding site shown in the typical TnI amino acid sequences. Homology analysis revealed that GrybiTnI exhibited high similarity at the amino acid level to those of other insects already reported; 89~77% identity with those of other insects. Expression of GrybiTnI by starvation did not change in dorsal wing flight muscle and dorsal ventral flight muscle, but showed up-expression in dorsal longitudinal flight muscle. In the digestive tracts, the up-expression of GrybiTnI by starvation was observed only in the hindgut but not in the rest parts including Malpighian tubules. Re-feeding following starvation restored those expressions about the level before starvation in the dorsal longitudinal flight muscle and hindgut. In conclusion, troponin modulates gene expression not only to muscle elements but also to physiological changes such as strains.

Existe pouca informação sobre a expressão gênica da troponina por inanição no músculo esquelético de insetos e no trato digestório. O objetivo deste estudo foi realizar clonagem molecular da troponina I do grilo africano, Gryllus bimaculatus (GrybiTnI) e determinar seus padrões de expressão em três diferentes músculos esqueléticos e tratos digestivos durante a inanição. GrybiTnI foi traduzido em uma proteína codificando 198 aminoácidos com um ponto isoelétrico teórico de 9,78 e um peso molecular de 23671,46 Da. O GrybiTnI tem o local de ligação a TnC e o local de ligação a actina/TnC mostrado nas sequências de aminoácidos TnI típicas. A análise de homologia revelou que GrybiTnI exibiu alta similaridade no nível de aminoácidos em relação àqueles de outros insetos já relatados; 89~77% de identidade com os de outros insetos. A expressão de GrybiTnI pela inanição não se alterou no músculo de vôo da asa dorsal e no músculo de vôo ventral dorsal, mas mostrou expressão positiva no músculo de vôo longitudinal dorsal. Nos tratos digestivos, a expressão positiva de GrybiTnI por inanição foi observada apenas no intestino grosso, mas não nas partes de repouso, incluindo os túbulos de Malpighi. A realimentação após a inanição restaurou as expressões aproximadamente ao nível antes da inanição no músculo de vôo longitudinal dorsal e no intestino grosso. Em conclusão, a troponina modula a expressão gênica não apenas em elementos musculares, mas também em alterações fisiológicas, como as cepas.

Molecular characterization and expression analysis of cathepsin C in Chinese giant salamander (Andrias davidianus) after Aeromonas hydrophila infection

Background: Cathepsin C (CTSC) (dipeptidyl peptidase I, DPPI), is a member of the papain superfamily of cysteine proteases and involves in a variety of host reactions. However, the information of CTST in Chinese giant salamander (Andrias davidianus), an amphibian species with important evolutionary position and economic values, remained unclear. Results: The full-length salamander CTSC cDNA contained a 96 bp of 5'-UTR, a 1392 bp of ORF encoding 463 amino acids, and a 95 bp of 3'-UTR. The salamander CTSC possessed several sequence features similar to other reported CTSCs such as a signal peptide, a propeptide and a mature peptide. The active site triad of Cys, His and Asn were also found existing in salamander CTSC. Salamander CTSC mRNA was constitutively expressed in all the examined tissues with significantly variant expression level. The highest expression of CTSC was in intestine, followed with stomach, spleen, lung and brain. Following Aeromonas hydrophila infection for 12 h, salamander CTSC was significantly up-regulated in several tissues including lung, spleen, brain, kidney, heart, stomach and skin. Conclusion: CTSC plays roles in the immune response to bacterial infection, which provided valuable information for further studying the functions of CTSC in salamander.

Analysis of bioinformatics and expression level of bHLH transcription factors in Scutellaria baicalensis / 中草药

Objective The information of bHLH transcription factor genes from transcriptome dataset of Scutellaria baicalensis was predicted by bioinformatics methods and the gene expression analysis was used to deduce its probable function. Methods The bHLH genes were screened from the transcriptome dataset of S. baicalensis by using BLAST comparison software. Then the open reading frames (ORFs) from the full-length of cDNA of bHLH genes were predicted by ORF Finder online tool, and its protein characteristics were analyzed using bioinformatic method. The expression of bHLH genes was detected by qPCR in different organs and treatments stimulated by Gibberellin A3 (GA3). Results Six genes of bHLH transcription factors were obtained, which belonged to six subfamilies of bHLHs of A. thaliana, two of which had completed ORFs. The results of gene expression showed that: The expression of bHLH2 and bHLH3 increased after 100 μmol/L GA3 treatment, and the expression of bHLH1, bHLH5, bHLH6 and bHLH7 decreased. The bHLH gene had the highest expression level in roots and flowers of S. baicalensis of them, among which bHLH1, bHLH2, bHLH5 and bHLH7 had highest expression in flowers and bHLH3 had highest expression in root. There was a correlation between bHLH gene and expression of biosynthesis and regulation genes of flavonoid. Conclusion These results provided the basis for further improving the molecular regulation network of flavonoids of bHLH genes in S. baicalensis.

cDNA cloning and prediction of antigenic determinants of protein marker IP4 in Ophiocordyceps sinensis / 中草药

Objective To clone the full-length of cDNA protein marker cyanase (IP4) of Ophiocordyceps sinensis and predict the antigenic sites. Methods The information of protein marker of O. sinensis was obtained by proteomics technology. The transcriptome database of O. sinensis and mycelium constructed in our lab were used to analyze IP4 unigenes and appropriate primers designed to amplify IP4, which was then cloned and sequenced. The conserved sequence of IP4, homology comparison, and the antigenic site were analyzed by DNAMAN6.0 and DNAStar software. Results Two alternative splice variants of IP4 were discovered from the transcriptome data and belonged to the invariant alternative splicing. The protein marker of O. sinensis was identified as cyanate hydratase, 465 bp, encoding 154 aa. The analysis of the conserved and functional regions showed that catalytic site and binding site mainly lied in C-terminal of IP4. Analysis of DNAMAN 6.0 showed that species 1-39 aa and 55-81 aa were of higher species specificity, and DNAStar results showed that the epitope region of IP4 protein is distributed from 25 to 90 aa. Conclusion The optimal antigen region of IP4 lied in the region 25-39 and 55-81 aa, which lays a foundation for the subsequent large-scale preparation of IP4 protein and eutilizing ELISA to identify authenticity of O. sinensis.

Sequence analysis of the cDNA encoding for SpCTx: a lethal factor from scorpionfish venom ( Scorpaena plumieri )

Background: Lethal factors are multifunctional oligomeric proteins found in the venomous apparatus of Scorpaeniformes fish. These toxins elicit not only an array of biological responses in vitro but also cardiovascular disorders and strong hemolytic, nociceptive and edematogenic activities in vivo. This work describes the cloning and molecular identification of two toxin subunits, denominated Sp-CTx- and Sp-CTx-, from scorpionfish venom ( Scorpaena plumieri ). Methods: The primary structures were deduced after cDNA amplification by PCR with primers from conserved sequences described in Scorpaeniformes toxins. Following DNA sequencing and bioinformatic analysis, the tridimensional structures of both subunits were modeled. Results: The translated sequences (702 amino acids, each subunit) show homology with other lethal factors, while alignment between Sp-CTx- and Sp-CTx- shows 54% identity. The subunits lack N-terminal signal sequences and display masses of approximately 80 kDa each. Both Sp-CTx subunits display a B30.2/SPRY domain at the C-terminal region with typically conserved motifs as described in these toxins. Secondary structure prediction identified six -helices 18 residues long in both and subunits, some of them amphiphilic with their N-terminal flanked by many basic residues, creating a cationic site associated with the cytolytic activity of these toxins. Antimicrobial potential sites were identified in Sp-CTx and share some features with other peptides presenting variable and broad-spectrum activity...

Sequence analysis of the cDNA encoding for SpCTx: a lethal factor from scorpionfish venom ( Scorpaena plumieri )

Lethal factors are multifunctional oligomeric proteins found in the venomous apparatus of Scorpaeniformes fish. These toxins elicit not only an array of biological responses in vitro but also cardiovascular disorders and strong hemolytic, nociceptive and edematogenic activities in vivo. This work describes the cloning and molecular identification of two toxin subunits, denominated Sp-CTx-α and Sp-CTx-ß, from scorpionfish venom ( Scorpaena plumieri ). Methods: The primary structures were deduced after cDNA amplification by PCR with primers from conserved sequences described in Scorpaeniformes toxins. Following DNA sequencing and bioinformatic analysis, the tridimensional structures of both subunits were modeled. Results: The translated sequences (702 amino acids, each subunit) show homology with other lethal factors, while alignment between Sp-CTx-α and Sp-CTx-ß shows 54% identity. The subunits lack N-terminal signal sequences and display masses of approximately 80 kDa each. Both Sp-CTx subunits display a B30.2/SPRY domain at the C-terminal region with typically conserved motifs as described in these toxins. Secondary structure prediction identified six α-helices 18 residues long in both α and ß subunits, some of them amphiphilic with their N-terminal flanked by many basic residues, creating a cationic site associated with the cytolytic activity of these toxins. Antimicrobial potential sites were identified in Sp-CTx and share some features with other peptides presenting variable and broad-spectrum activity. A phylogenetic tree built to represent these toxins supports the proximity between scorpionfish, lionfish and stonefish. Conclusion: The study identified a putative toxin protein whose primary structure is similar to other fish toxins and with potential for production of antivenom against scorpionfish envenomation in Brazil. As a prelude to structure-function studies, we propose that the toxin is structurally related to pore-forming marine toxins.(AU)

Molecular cloning and characterisation of scavenger receptor class B in pearl oyster Pinctada fuctada martensii

Background: Molluscs can accumulate carotenoids in their body tissues by predominantly feeding on aquatic plant sources. Carotenoid transport and absorption are determined by the regulation of various proteins such as Scavenger receptor class B(SR-BI). We report the identification and characterisation of pearl oyster Pinctada fuctada martensii SR-BI (PmSR-BI). The correlation between total carotenoid content (TCC) and gene expression was also estimated. Results: The full-length cDNA of PmSR-BI was 1828 bp, including an open-reading frame encoding of 1518 bp with a pI value of 5.83. PmSR-BI protein contains a hydrophobic CD36 domain and four centrally clustered cysteine residues for the arrangement of disulphide bridges. The deduced amino acid sequence had an identity of 30% to 60% with the SR-B of other organisms. Reverse transcription polymerase chain reaction analysis showed that mRNA transcripts were expressed in multiple tissues of adult pearl oyster. A higher expression of PmSR-BI gene was observed in the hepatopancreas than in the adductor muscle, gill and mantle. The TCC and gene expression of PmSR-BI were significantly correlated (P b 0.05), with a correlation coefficient of 0.978. Conclusions: The results suggested that PmSR-BI is involved in the absorption of carotenoids in the pearl oyster P. fuctada martensii.