Célia R C Franco

Universidade Federal do Paraná, Curityba, Paraná, Brazil

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Publications (30)60.5 Total impact

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    [Show abstract] [Hide abstract] ABSTRACT: Tanacetum vulgare L., popularly known as tansy, is used in traditional medicine as a vermifuge, digestive and emmenagogue. This study aimed to analyze the morphoanatomical leaves and stems of this medicinal plant in order to control the quality. Usual techniques of light and scanning electron microscopy were used. The leaves are composed, pinatissect and amphistomatic. Simple and flagelliform non- glandular trichomes and capitate glandular trichomes are observed. The midrib has biconvex shape, the petiole is concavo-convex, the rachis is plano-convex, and the stem is rounded. Collateral vascular bundles, perivascular fiber caps and laminar collenchyma are encountered in the leaves and stems. Evidenced the morphological and anatomical features contribute to the identification of the taxon and provide pharmacobotanical data for the quality control of herbal drugs.
    Full-text · Article · Mar 2016
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    [Show abstract] [Hide abstract] ABSTRACT: In southern Brazil, the bottled latex of Synadenium grantii Hook f., Euphorbiaceae, is popularly used as a treatment of all types of cancer. Similarly, Synadenium umbellatum Pax. is used in the central western region of Brazil for the same purpose and in the same manner of use. Both plants are popularly known as janaúba or leitosinha. The objectives of this study were to use pharmacobotanical analysis to verify whether these two species, which are considered to be distinct, are actually the same to determine anatomical markers; to assist in the identification and differentiation of other Euphorbia; and to evaluate the cytotoxic activity of the latex in relation to HeLa and HRT-18 cells. Leaves and stems of the species were collected in Goiânia and Ponta Grossa and were investigated using scanning electron microscopy and optical microscopy techniques. The latex was also collected and analyzed in relation to its cytotoxic effect by employing MTT and NR techniques. The pharmacobotanical study of the specimens in both localities showed that they were the same species, namely Euphorbia umbellata (Pax) Bruyns, which is the scientific nomenclature accepted and confirmed by an expert taxonomist who specializes in Euphor-bia. The pharmacobotanical characteristics highlighted in this study can assist in the identification of the taxon and contribute to the control of the quality of this plant drug. The evaluation of the latex in relation to HRT-18 cells demonstrated action after 48 h of experiment. In contrast, in relation to HeLa cells its induced cytotoxicity in all times and a dose-dependent manner. The IC 50 values (72 h) observed were 252.58 ± 18.51 g/ml and 263.42 ± 15.92 g/ml to MTT experiment and 250.18 ± 19.48 g/ml and 430.56 ± 19.71 g/ml to NR experiment for the HeLa and HRT-18 cells, respectively.
    Full-text · Article · Jul 2015 · Revista Brasileira de Farmacognosia
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    [Show abstract] [Hide abstract] ABSTRACT: Piper amalago L., Piperaceae, popularly known as jaborandi-manso, is a shrub that spans a height of 2–7 m. It can be found in the regions of Southern America downward up to the south of Brazil. Traditionally it is used to treat digestive problems, heart problems, and burns. This study aims to conduct an anatomical investigation and analysis of the leaves and stems of P. amalago through electron scanning and optical micro techniques. The analysis showed that P. amalago has a hypostomatic leaf, with a subepidermal layer on its surface. There are grandular trichomes that resemble sacs, conic non-glandular trichomes, dorsiventral mesophyll, and a plano-convex midrib having a single vascular bundle in the center. The petiole is short with irregularly shaped and adaxially grooved. The stem is circular in shape and contains two circles of vascular bundles and a sclerenchymatic sheath in the perimedular region. These anatomical features of the Piper amalago's leaves and stems make it easy to pick it out among other species of the Piper genus. This is helpful when conducting quality control process.
    Full-text · Article · Mar 2015 · Revista Brasileira de Farmacognosia
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    [Show abstract] [Hide abstract] ABSTRACT: . Mikania micranha Kunth, commonly known as guaco, is a perennial twining herb which is often used as a traditional medicine. It has antimicrobial, antiprotozoal, antiviral, anti-inflammatory, and anti-tumoral properties. The aim of this study was to investigate the pharmacobotanical characters of the leaf and stem of M. micrantha as a means of classifying it and differentiating it from other species of Mikania. The usual techniques of optical microscopy and scanning electron microscopy were employed. An examination of the leaves morphology, midrib, petiole and stem shape in transection, together with the organization of the vascular bundles in the midrib and the data of trichomes can assist in the diagnosis of M. micrantha. RESUMEN. Mikania micranha Kunth, comúnmente conocida como guaco, es una hierba perenne que se utiliza a menudo como medicina tradicional. Tiene propiedades antimicrobianas, antiprotozoarias, antivirales, anti-infla-matorias y anti-tumorales. El objetivo de este estudio fue investigar los caracteres farmacobotánicos de la hoja y tallo de M. micrantha como un medio para clasificarla y diferenciarla de otras especies de Mikania. Se emplea-ron las técnicas habituales de microscopía óptica y microscopía electrónica de barrido. Un examen de la morfolo-gía de hojas, nervadura central, pecíolo y tallo en transección, junto con la organización de los haces vasculares en la nervadura central y los datos de tricomas pueden ayudar en el diagnóstico de M. micrantha.
    Full-text · Article · Jan 2015 · LATIN AMERICAN JOURNAL OF PHARMACY
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    [Show abstract] [Hide abstract] ABSTRACT: Dioscorea bulbifera L. is commonly known in Brazil as inhame, cará-de-árvore, cará-do-ar, cará-moela, batata-do-ar, and cará-de-sapateiro. Pharmacological studies have demonstrated anti-nociceptive, cytotoxic, hypoglycemic, antimicrobial and cardiovascular activities. The present work was to carry out morpho-anatomical research of leaves, stems and tubers of D. bulbifera L. as a contribution to the quality control. The botanical material was investigated according to standard methods of light and scanning electron microscopy. D. bulbifera L. has leaves simple and varying sagitiform to cordiform in shape, uniseriate epidermis, amphistomatic leaves with anisocytic and anomocytic stomata. Non-glandular trichome was not observed and glandular trichomes occur on both surfaces. Glandular trichomes are capitate with multicellular head. The mesophyll is dorsiventral. Petiole is concave-convex with 3 conspicuous ribs and two ventral winged lobes; all ribs internally fill by angular collenchyma. The stems showed 8 ribs, cuticle striate, and mucilage idioblasts and a sclerenchymatic ring was present in the cortex. The tuber has several cork layers and the parenchyma cells accumulate several starch grains with irregular shape. © 2014, Colegio de Farmaceuticos de la Provincia de Buenos Aires. All right reserved.
    Full-text · Article · Jan 2014 · LATIN AMERICAN JOURNAL OF PHARMACY
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    [Show abstract] [Hide abstract] ABSTRACT: Sulfated polysaccharides (SP) are found mainly in seaweeds and animals. To date, they have only been found in six plants and all inhabit saline environments. Furthermore, there are no reports of SP in freshwater or terrestrial plants. As such, this study investigated the presence of SP in freshwaters Eichhornia crassipes, Egeria densa, Egeria naja, Cabomba caroliniana, Hydrocotyle bonariensis and Nymphaea ampla. Chemical analysis identified sulfate in N. ampla, H. bonariensis and, more specifically, E. crassipes. In addition, chemical analysis, FT-IR spectroscopy, histological analysis, scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDXA), as well as agarose gel electrophoresis detected SP in all parts of E. crassipes, primarily in the root (epidermis and vascular bundle). Galactose, glucose and arabinose are the main monosaccharides found in the sulfated polysaccharides from E. crassipes. In activated partial thromboplastin time (APTT) test, to evaluate the intrinsic coagulation pathway, SP from the root and rhizome prolonged the coagulation time to double the baseline value, with 0.1 mg/mL and 0.15 mg/mL, respectively. However, SP from the leaf and petiole showed no anticoagulant activity. Eichornia SP demonstrated promising anticoagulant potential and have been selected for further studies on bioguided fractionation; isolation and characterization of pure polysaccharides from this species. Additionally in vivo experiments are needed and are already underway.
    Full-text · Article · Dec 2012 · International Journal of Molecular Sciences
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    [Show abstract] [Hide abstract] ABSTRACT: Baccharis rufescens Spreng. var. tenuifolia (DC.) Baker belongs to the Asteraceae family. It is used for liver and stomach problems in traditional medicine. Previous phytochemical data reported flavonoid and triterpene contents. Chloroform and methanol extracts of the leaves showed activity in the bioassay of brine shrimp. Chloroform extracts showed the presence of peroxides that can be used to treat malaria (Schenkel et al., 2002; Montanher et al., 2002; Moreira et al., 2003). Considering the pharmacological importance of B. rufescens var. tenuifolia, the purpose of this paper was to perform the anatomical analysis of aerial vegetative parts of Baccharis rufescens var. tenuifolia in order to provide pharmacognostic data for quality control. The plant material was studied by the usual methods of light and scanning electron microscopy. Amphistomatic leaves, anomocytic stomata, biseriate capitate glandular trichomes, uniseriate simple flagelliform non-glandular trichomes, secretory ducts associated to the phloem, perivascular fiber cap, calcium oxalate as prismatic and styloid crystals in the pith of the stem were reported as the mainly anatomical data for B. rufescens var. tenuifolia.Ouvir Ler foneticamente
    Full-text · Article · Dec 2012 · Revista Brasileira de Plantas Medicinais
  • [Show abstract] [Hide abstract] ABSTRACT: We compared the structures and rheology of xanthan-galactomannan (X:G) hydrogels with the addition of curcumin in microemulsion (X:GMC) and ethanol (X:GEC). X:GMC hydrogels have gel characteristics and exhibited a significantly higher elastic response than the X:GEC and X:G hydrogels at room temperature, but after heating, an increase in the elastic modulus was observed for the last two systems. The visualization of the hydrogel microstructures by cryo-scanning electronic microscopy revealed pores within the lamellar structure only for X:GMC. In vitro skin permeation tests showed a more pronounced lag time for X:GMC; however, a more efficient permeation from X:GMC than from X:GEC. This study demonstrates that the X:G system is an alternative to traditional gels for the topical applications of hydrophobic drugs.
    No preview · Article · Jul 2012 · Journal of Pharmaceutical Sciences
  • [Show abstract] [Hide abstract] ABSTRACT: Objective: The aim of this study was to evaluate the effects of platelet rich plasma on established endothelial cell lineage. Method: Rabbit Aortic Endothelial Cells (RAEC) were treated with rabbit platelet-rich plasma during seven days. The treated cells were tested for cell viability, cytotoxicity, adhesion, spreading, quantification of α5β1 receptor and apoptosis percentage according to literacture standards. Result: The present in vitro study shows that PRP treatment induced loss of cell viability. PRP also exerted cellular cytotoxicity, by impairing mitochondrial metabolism. PRP induced to morphological changes in cells exposed to PRP, similar to the one seen on fibrous phenotypes. By SEM, the subconfluent treated cells (ST) and confluent treated cells (CT) were well adhered, sprawling and emitting a number of filopodia. The CT showed clear contact inhibition. The results demonstrate that both ST and CT ahd higher expression of α5β1 receptor on the cell surface. The adhesion tests shown that cells exposed to PRP adhere significantly more to fibronectin than the controls. Similar results similar were also seen for the cell spreading, where ST and CT were more sprawled than control cells. ST cells showed significantly larger percentages of apoptosis compared to confluent cells, being ST and CT both higher than the control. Conclusion: These results favor the conclusion that PRP may induce morphological and ultrastructural changes in endothelial cells (RAEC) with possible cell transdifferentiation.
    No preview · Conference Paper · Jun 2012
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    [Show abstract] [Hide abstract] ABSTRACT: Brown spider (Loxosceles sp.) venom affects the endothelium of vessels and triggers disruptive activity in the subendothelial matrix. The vascular disorders observed after venom exposure include leukocyte and platelet activation, disseminated intravascular coagulation, an increase in vessel permeability and hemorrhage into the dermis. In this study, we report additional evidence regarding the mechanism of endothelial cell cytotoxicity induced by Loxosceles intermedia venom. Exposure to venom led to endothelial cell detachment in a time-dependent manner. Loss of cell anchorage and cell-cell adhesion following venom exposure was accompanied by changes in the distribution of the α₅β₁ integrin and VE-cadherin. An ultrastructural analysis of cells treated with venom revealed morphological alterations characteristic of apoptosis. Moreover, after venom exposure, the ratio between Bax and Bcl-2 proteins was disturbed in favor of Bax. In addition, late apoptosis was only observed in cells detached by the action of venom. Accordingly, there was no increase in apoptosis when cells were exposed to L. intermedia venom in suspension, suggesting that the loss of cell anchorage provides the signal to initiate apoptosis. Thus, L. intermedia venom likely triggers endothelial cell death indirectly through an apoptotic mechanism known as anoikis.
    Full-text · Article · Apr 2012 · Toxicon
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    [Show abstract] [Hide abstract] ABSTRACT: The genus Baccharis L. belongs to Asteraceae and comprises several medicinal species. Both Baccharis spicata (Lam.) Baill. and Baccharis curitybensis Heering ex Malme are traditionally known as "vassoura" (broom) in Brazil. The species B. spicata has antibacterial, antioxidant and trypanocidal activities. Despite of B. curitybensis shows an external morphology quite similar to B. spicata, no chemical and pharmacological study is available about B. curitybensis. Therefore some confusion and/or problems can occur during popular use. In order to differentiate these taxa, the morpho-anatomy of their leaves and stems were investigated according to the usual light and scanning electron microtechniques. The species B. curitybensis reveals smooth and revolute margin, alternate leaf arrangement and non-capitate uniseriate glandular trichomes. Otherwise, dentate and flat margin, opposite leaf arrangement and uniseriate flagel-liform non-glandular trichomes are observed in B. spicata. Morphological and anatomical data can be useful for differentiating B. curitybensis and B. spicata.
    Full-text · Article · Oct 2011 · LATIN AMERICAN JOURNAL OF PHARMACY
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    [Show abstract] [Hide abstract] ABSTRACT: Aging and a variety of pathologies, including cancer, diabetes, cardiovascular and inflammatory diseases have been associated with reactive oxygen species (ROS), such as superoxide anion (O₂·⁻), hydroxyl radical (·OH) and hydrogen peroxide (H₂O₂) generation. Plant polyphenols bear radical scavenging/antioxidant activity. A phytomedicinal preparation obtained from aerial parts of Dicksonia sellowiana (Dicksoniaceae), a native plant from Central and South America, has been widely used in Brazil against asthma and presents beneficial effects in several other diseases, including cardiovascular disturbance. In this work, we investigated whether Dicksonia sellowiana, which is also known to contain high levels of polyphenols, presents antioxidant activity. The antioxidant activity of the hydroalcoholic extract obtained from Dicksonia sellowiana leaves (HEDS) was investigated by in vitro and in vivo tests. HEDS (0.1-100 μg/mL) exhibited a strong scavenging activity against all reactive species tested (DPPH, O₂·⁻,·OH and H₂O₂; IC₅₀=6.83±2.05, 11.6±5.4, 2.03±0.4, and 4.8±0.4 μg/mL, respectively). HEDS strongly protected endothelial cells against H₂O₂-induced oxidative stress by mechanisms other than increasing catalase activity. In addition, HEDS protected cell membrane from oxidative damage. HEDS, (20 and 40 mg/kg) inhibited lipid peroxidation in vivo (29.8% and 24.5%, respectively). According to our results, we can speculate that the traditional uses of Dicksonia sellowiana for cardiovascular diseases, asthma and skin diseases could be, at least in part, related to the potent antioxidant and endothelial protective activities of the plant.
    Full-text · Article · Feb 2011 · Journal of ethnopharmacology
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    [Show abstract] [Hide abstract] ABSTRACT: Bites from the Loxosceles genus (brown spiders) cause severe clinical symptoms, including dermonecrotic injury, hemorrhage, hemolysis, platelet aggregation and renal failure. Histological findings of dermonecrotic lesions in animals exposed to Loxosceles intermedia venom show numerous vascular alterations. Study of the hemorrhagic consequences of the venom in endothelial cells has demonstrated that the degeneration of blood vessels results not only from degradation of the extracellular matrix molecule or massive leukocyte infiltration, but also from a direct and primary activity of the venom on endothelial cells. Exposure of an endothelial cell line in vitro to L. intermedia venom induce morphological alterations, such as cell retraction and disadhesion to the extracellular matrix. The aim of the present study was to investigate the interaction between the venom toxins and the endothelial cell surface and their possible internalization, in order to illuminate the information about the deleterious effect triggered by venom. After treating endothelial cells with venom toxins, we observed that the venom interacts with cell surface. Venom treatment also can cause a reduction of cell surface glycoconjugates. When cells were permeabilized, it was possible to verify that some venom toxins were internalized by the endothelial cells. The venom internalization involves endocytic vesicles and the venom was detected in the lysosomes. However, no damage to lysosomal integrity was observed, suggesting that the cytotoxic effect evoked by L. intermedia venom on endothelial cells is not mediated by venom internalization.
    Full-text · Article · Sep 2010 · Toxicon
  • [Show abstract] [Hide abstract] ABSTRACT: Alpha5beta1 integrin from both wild-type CHO cells (CHO-K1) and deficient in proteoglycan biosynthesis (CHO-745) is post-translationally modified by glycosaminoglycan chains. We demonstrated this using [35S]sulfate metabolic labeling of the cells, enzymatic degradation, immunoprecipitation reaction with monoclonal antibody, fluorescence microscopy, and flow cytometry. The alpha5beta1 integrin heterodimer is a hybrid proteoglycan containing both chondroitin and heparan sulfate chains. Xyloside inhibition of sulfate incorporation into alpha5beta1 integrin also supports that integrin is a proteoglycan. Also, cells grown with xyloside adhered on fibronectin with no alteration in alpha5beta1 integrin expression. However, haptotactic motility on fibronectin declined in cells grown with xyloside or chlorate as compared with controls. Thus, alpha5beta1 integrin is a proteoglycan and the glycosaminoglycan chains of the integrin influence cell motility on fibronectin. Similar glycosylation of alpha5beta1 integrin was observed in other normal and malignant cells, suggesting that this modification is conserved and important in the function of this integrin. Therefore, these glycosaminoglycan chains of alpha5beta1 integrin are involved in cellular migration on fibronectin.
    No preview · Article · Aug 2009 · Biochemistry and Cell Biology
  • [Show abstract] [Hide abstract] ABSTRACT: Endothelins, acting through specific endothelin ET(A) and/or ET(B) receptors, participate in nociceptive processing in models of cancer, inflammatory and neuropathic pain. The present study investigated which cell types express endothelin receptors in the trigeminal ganglion, and the contribution of mechanisms mediated by endothelin ET(A) and ET(B) receptors to orofacial heat hyperalgesia induced by unilateral constriction of the infraorbital nerve (CION). Both receptor types were identified by immunohistochemistry in the trigeminal ganglion, ET(A) receptors on small-sized non-myelinated and myelinated A-fibers and ET(B) receptors on both satellite glial cells and small-sized non-myelinated neuronal cells. CION promoted ipsilateral orofacial heat hyperalgesia which lasted from Day 2 until Day 10 after surgery. Ongoing CION-induced heat hyperalgesia (on Day 4) was reduced transiently, but significantly, by systemic or local treatment with antagonists of endothelin ET(A) receptors (atrasentan, 10 mg/kg, i.v.; or BQ-123, 10 nmol/lip), endothelin ET(B) receptors (A-192621, 20 mg/kg, i.v.; or BQ-788, 10 nmol/ lip), or of both ET(A)/ET(B) receptors (bosentan, 10 mg/kg, i.v.; or BQ-123 plus BQ-788, each at 10 nmol/lip). On the other hand, CION-induced heat hyperalgesia was transiently abolished over the first 90 min following i.p. injection of morphine hydrochloride (2.5 mg/kg), but fully resistant to reversal by indomethacin (4 mg/kg, i.p.) or celecoxib (10 mg/kg, i.p.). Thus, heat hyperalgesia induced by CION is maintained, in part, by peripheral signaling mechanisms operated by ET(A) and ET(B) receptors. Endothelin receptors might represent promising therapeutic targets for the control of trigeminal neuropathic pain.
    No preview · Article · Feb 2009 · Neuropeptides
  • [Show abstract] [Hide abstract] ABSTRACT: Exposure of endothelial cells to heparin and other antithrombotic drugs specifically stimulates the synthesis of an antithrombotic heparan sulfate (HS). In the present work, biotinylated heparin (BiotHep) was used to characterize the binding site(s) of heparin responsible for the stimulus in HS synthesis on endothelial cells. No differences were observed between biotinylated and non-biotinylated heparin in their ability to increase the synthesis of HS. In kinetic studies the BiotHep showed fast, saturable and specific binding with an apparent K(D) of 83 nM to adherent cells and 44 nM to the extracellular matrix (ECM) in the absence of cells. By confocal and electron microscopy, BiotHep bound only to the ECM, co-localizing with fibronectin. The same pattern of binding to the ECM was observed using heparin conjugated with FITC or Alexa Fluor 488 in the presence or absence of fetal calf serum. However, after degradation of HS, heparin binds to the cell surface, indicating that endogenous HS possibly occupied the heparin binding sites. Analyses by flow cytometry and confocal microscopy of cells with non-associated ECM, showed labeling of the cell surface using syndecan-4 monoclonal antibody as well as wheat germ agglutinin, but no binding of heparin. Furthermore, the stimulation in HS synthesis is not elicited by heparin in the absence of ECM. These results indicate that the stimulus for the synthesis of HS does not require binding of the heparin to the cell surface, and the signaling may be mediated through the ECM.
    No preview · Article · Nov 2008 · Journal of Cellular Physiology
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    [Show abstract] [Hide abstract] ABSTRACT: In vitro, heparin and antithrombotic drugs specifically stimulate the synthesis of an antithrombotic heparan sulfate proteoglycan (HSPG) produced by endothelial cells. The putative heparin binding site(s) that may be related to this phenomenon were investigated. In the preceding article, using various heparin probes, it was shown that the heparin does not bind to the endothelial cell surface, but only to the extracellular matrix. The present study demonstrated that, when the cells were exposed to heparin at 37 degrees C, the heparin was internalized and with time was localized in lysosomes. However, endocytosis of heparin was not required for the stimulation of HSPG synthesis. The requirement for heparin degradation in the stimulus of HSPG synthesis was also investigated. When the cells were incubated with chloroquine, a lysosomotropic amine that raises the lysosomal pH thus inhibiting enzymatic degradation of internalized compounds, stimulation of HSPG synthesis was still observed. These combined results indicate that neither internalization nor degradation of heparin is required for stimulation of HSPG synthesis, and suggests that its binding to the extracellular matrix could be responsible for this effect.
    Full-text · Article · Nov 2008 · Journal of Cellular Physiology
  • [Show abstract] [Hide abstract] ABSTRACT: Fucan is a term used to denominate a family of sulfated L-fucose-rich polysaccharides. The brown alga Spatoglossum schröederi (Dictyotaceae) has three heterofucans namely fucan A, B and C. The 21 kDa fucan A is composed of a core of a beta (1-3) glucuronic acid-containing oligosaccharide of 4.5 kDa with branches at C4 of the fucose chains alpha (1-3) linked. The fucose is mostly substituted at C4 with a sulfate group and at C2 with chains of beta (1-4) xylose. This fucan has neither anticoagulant (from from 0.1 to 100 microg) nor hemorrhagic activities (from 50 to 800 microg/mL). The antithrombotic test in vivo showed that fucan A has no activity in any of the concentrations (from 0.2 to 20 microg/g/day) tested 1 h after polysaccharide administration. However, when fucan A was injected endovenously 24 h before the ligature of the venae cavae, we observed a dose-dependent effect, reaching saturation at around 20 microg/g of rat weight. In addition, this effect is also time-dependent, reaching saturation around 16 h after fucan administration. In addition, regardless of the administration route, fucan A displayed antithrombotic activity. The exception was the oral pathway. Of particular importance was the finding that fucan A stimulates the synthesis of an antithrombotic heparan sulfate from endothelial cells like heparin. The hypothesis has been raised that the in vivo antithrombotic activity of fucan A is related to the increased production of this heparan. Taken together with the fact that the compound is practically devoid of anticoagulant and hemorrhagic activity, the data suggest that it may be an ideal antithrombotic agent in vivo.
    No preview · Article · Jul 2008 · Planta Medica
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    [Show abstract] [Hide abstract] ABSTRACT: Injuries caused by brown spiders (Loxosceles genus) are associated with dermonecrotic lesions with gravitational spreading and systemic manifestations. The venom has a complex composition containing many different toxins, of which metalloproteases have been described in many different species of this genus. These toxins may degrade extracellular matrix constituents acting as a spreading factor. By using a cDNA library from an Loxosceles intermedia venom gland, we cloned and expressed a 900 bp cDNA, which encoded a signal peptide and a propeptide, which corresponded to a 30 kDa metalloprotease, now named LALP (Loxosceles astacin-like protease). Recombinant LALP was refolded and used to produce a polyclonal antiserum, which showed cross-reactivity with a 29 kDa native venom protein. CD analysis provided evidence that the recombinant LALP toxin was folded correctly, was still in a native conformation and had not aggregated. LALP addition to endothelial cell cultures resulted in de-adhesion of the cells, and also in the degradation of fibronectin and fibrinogen (this could be inhibited by the presence of the bivalent chelator 1,10-phenanthroline) and of gelatin in vitro. Sequence comparison (nucleotide and deduced amino acid), phylogenetic analysis and analysis of the functional recombinant toxin revealed that LALP is related in both structure and function to the astacin family of metalloproteases. This suggests that an astacin-like toxin is present in a animal venom secretion and indicates that recombinant LALP will be a useful tool for future structural and functional studies on venom and the astacin family.
    Full-text · Article · Oct 2007 · Biochemical Journal
  • [Show abstract] [Hide abstract] ABSTRACT: Purified from Bauhinia rufa seeds, BrTI is a Kunitz proteinase inhibitor that contains the RGD sequence. BrTI inhibits trypsin (K(iapp) 2.9 nM) and human plasma kallikrein (K(iapp) 14.0 nM) but not other related enzymes. The synthetic peptide YLEPVARGDGGLA-NH(2) (70 microM) inhibited the adhesion to fibronectin of B16F10 (high-metastatic B16 murine mouse melanoma cell line) and of Tm5 (murine melanoma cell lines derived from a non-tumorigenic lineage of pigmented murine melanocytes, melan-a). YLEPVARGEGGLA-NH(2) in which Asp(9) was changed into Glu does not affect the cell attachment. Moreover, this peptide was functional only when the sequence present in the native protein was preserved, since YLIPVARGDGGLA-NH(2) in which Glu(3) was changed into Ile does not interfere with B16F10 and was less effective on Tm5 cell line adhesion. Neither YLEPVARGDGGLA-NH(2), YLIPVARGDGGLA-NH(2) or YLEPVARGEGGLA-NH(2) inhibit the interaction of RAEC (endothelial cell line from rabbit aorta) with fibronectin.
    No preview · Article · Jan 2007 · International Journal of Biological Macromolecules