[Advancement on thrombolytic characteristic, function and clinical application of different fibrinolytic enzymes]

Cardio-cerebral vascular diseases endanger people's health very seriously. Thrombolytic therapy is effective in curing thrombotic diseases at present. Microorganism is an important source of thrombolytic drug. Plasminogen activators are widely used as thrombolytic drugs clinically, while they are still exists some defects. This article analyzed research and development status of kinds of thrombolytic drugs from microorganisms, and evaluated their clinical efficacy and safety, aiming at showing the direction to search new and effective thrombolytic drugs and prevent and treat thromboembolic disease.

[Isolation and identification of a fibrinolytic bacterium strain from frozen soil in the Tibetan Plateau]

OBJECTIVE

Cardiovascular disease, harmful to human health, is a worldwide disease, for which fibrinolytic enzyme is usually used as an effective remedy. Fibrinolytic microbes under extreme environmental conditions may excrete some high efficient and safe fibrinolytic enzymes. So, for obtaining this fibrinolytic enzyme, we isolated fibrinolytic strains from frozen soil in the Tibetan Plateau.

METHODS

We screened microbes hydrolyzing blood powder by blood powder (bovine) - agar plate, followed by detection of thrombolysis effect through thrombolytic test in vitro. After that, we detected and measured the fibrinolytic activity of those microbes screened above with fibrin plates. Finally, we classified and identified the fibrinolytic microbes by combining physiological and biochemical test and 16S rRNA gene sequence analysis.

RESULTS

We isolated a strain DR-536 from frozen soil at 4300 m altitude in Yushu Tibetan Autonomous Prefecture, Qinghai Province. We found that the strain DR-536 not only hydrolyzed blood powder in the blood-agar plate, but also completely dissolved thrombus in vitro. We also found that strain DR-536 could hydrolyze fibrin, and the fibrinolytic activity was 51.80 IU/ml (with Urokinase as a standard). At last, results of classification and identification indicated that DR-536 is a new strain of Arthrobacter aurescens with fibrinolytic function.

CONCLUSION

We provided a strain for research and exploitation of novel fibrinolytic enzymes.

Four new long-chain aliphatics from the feces of Trogopterus xanthipes

Chemical investigation of Trogopterus feces has led to the isolation of four new long-chain aliphatics, including two new fatty alcohols, 8,15-nonacosanediol (1) and 6,13-nonacosanediol (2), one new fatty acid ester, dihexyl 7,7'-oxydiheptanoate (3), and one new ceramide, (2R)-2-hydroxy-N-[(2S,3S,4R,11E)-1,3,4-trihydroxydocos-11-en-2-yl]heneicosanamide (4). Their structures were elucidated by means of chemical and extensive spectroscopic analysis. Compound 3 exhibited moderate activity of antithrombin in vitro.

Identification of a VWF peptide antagonist that blocks platelet adhesion under high shear conditions by selectively inhibiting the VWF-collagen interaction

BACKGROUND

Because the collagen-VWF-GPIb/IX/V axis plays an important role in thrombus formation, it represents a promising target for development of new antithrombotic agents.

OBJECTIVES

We used phage display to identify potential small peptides that interfere with the VWF-collagen binding and might serve as lead products for the development of possible oral antithrombotic compounds.

METHODS

A random linear heptamer peptide library was used to select VWF-binding peptides.

RESULTS

We identified a phage clone, displaying the YDPWTPS sequence, further referred to as L7-phage, that bound to VWF in a specific and a dose-dependent manner. This L7-phage specifically inhibited the VWF-collagen interaction under both static and flow conditions. Epitope mapping using deletion mutants of VWF revealed that the L7-phage does not bind to the known collagen-binding A3 domain within VWF, but to the more carboxyterminal situated C domain. This inhibition was not due to steric hindrance of the A3 domain-collagen interaction by the L7-phage. Indeed, a tetrabranched multi-antigen peptide (MAP) presenting four copies of the peptide, but not the scrambled MAP, also inhibited VWF-collagen interaction under conditions of high shear stress at a concentration of 148 nmol L(-1).

CONCLUSIONS

Based on these results, we conclude that we have identified the first peptide antagonist that binds to the VWF C domain and by this specifically inhibits the VWF binding to collagen, suppressing platelet adhesion and aggregation under high shear conditions. As a consequence, this peptide and its future derivates are potentially interesting antithrombotic agents.

Influence of molecular weight of chemically sulfated citrus pectin fractions on their antithrombotic and bleeding effects

Evaluated were the anticoagulant and antithrombotic activities, and bleeding effect of two chemically sulfated polysaccharides, obtained from citric pectin, with different average molar masses. Both low-molecular-weight (Pec-LWS, 3,600 g/mol) and high-molecular-weight sulfated pectins (Pec-HWS, 12,000 g/mol) had essentially the same structure, consisting of a (1-->4)-linked alpha-D-GalpA chain with almost all its HO-2 and HO-3 groups substituted by sulfate. Both polysaccharides had anticoagulant activity in vitro, although Pec-HWS was a more potent antithrombotic agent in vivo, giving rise to total inhibition of venous thrombosis at a dose of 3.5 mg/kg body weight. Surprisingly, in contrast with heparin, Pec-HWS and Pec-LWS are able to directly inhibit alpha-thrombin and factor Xa by a mechanism independent of antithrombin (AT) and/or heparin co-factor II (HCII). Moreover, Pec-HWS provided a lower risk of bleeding than heparin at a dose of 100% effectiveness against venous thrombosis, indicating it to be a promising antithrombotic agent.

Fibrinolytic compounds isolated from a brown alga, Sargassum fulvellum

Two of bioactive natural products were founded in a brown alga, Sargassum fulvellum. After isolation and purification, the molecular structures of these two products were investigated by NMR spectroscopy and GC-mass spectroscopy. The two compounds were identified to be 1-O-palmitoyl-2-O-oleoyl-3-O-(alpha-D-glucopyranosyl)-glycerol (POGG) and 1-O-myristoyl-2-O-oleoyl-3-O-(alpha-D-glucopyranosyl)-glycerol (MOGG) which were obtained from Sargassum fulvellum for the first time. POGG and MOGG showed fibrinolytic activity in the reaction system of pro-u-PA and plasminogen.

[Identification of a fibrinolytic enzyme producing Bacillus pseudomycoides and purification and characterization of the enzyme]

OBJECTIVE

To purify a single fibrinolytic enzyme from Bacillus pseudomycoides B-60 and to determine its N-terminal sequence and to characterize the fibrinolytic enzyme.

METHODS

We examined the fibrinolytic enzyme activity by fibrin plate and purified fibrinolytic enzyme by ammonium sulfate fractional precipitation and DEAE anion exchange chromatography.

RESULTS

Obtained a single protein fraction with fibrinolytic activity (BpFE) from B. pseudomycoides B-60. It appeared as a single band in the SDS-PAGE with a relative molecular weight of 34 kDa. The fibrinolytic activity of the protein was stable at 4-50 degrees C and at pH 5-10. The activity sharply decreased above 50 degrees C, and the total loss of activity at pH 3.0. The enzymatic activity was slightly enhanced by the ions of Ca2+, Mg2+, Mn2+, whereas strongly inhibited by Cu2+ ion. Phenylmethyl sulfonyl fluoride (PMSF) could completely inhibit its activity. In addition, the activity improved when the protein was enzymatically hydrolyzed using trypsin and pepsin. The first 15 amino acids of the N-terminal sequence of the enzyme were determined to be VTGTNAVGTGKGVLG. The partial amino acids sequence alignment study of the enzyme from B-60 strain with bacillolysin, neutral protease and hydrolase which were from B. cereus, B. thuringiensis, B. anthracis and Lactobacillus sp. was carried out, and there is a 100% homogeneity between them.

CONCLUSION

We obtained a single fibrinolytic enzyme. Through its N-terminal sequence alignment study, a plasmin with high homogeneity to this protein was not found yet. This provided a basis for further study of new thrombolytic drugs.

Venom variation in hemostasis of the southern Pacific rattlesnake (Crotalus oreganus helleri): isolation of hellerase

Envenomations by the southern Pacific rattlesnake (Crotalus oreganus helleri) are the most common snakebite accidents in southern California. Intraspecies venom variation may lead to unresponsiveness to antivenom therapy. Even in a known species, venom toxins are recognized as diverse in conformity with interpopulational, seasonal, ontogenetic and individual factors. Five venoms of individual C. oreganus helleri located in Riverside and San Bernardino counties of southern California were studied for their variation in their hemostatic activity. The results demonstrated that Riverside 2 and San Bernardino 1 venoms presented the highest lethal activity without hemorrhagic activity. In contrast, San Bernardino 2 and 3 venoms had the highest hemorrhagic and fibrinolytic activities with low lethal and coagulant activities. Riverside 1, Riverside 2 and San Bernardino 1 venoms presented a significant thrombin-like activity. San Bernardino 2 and 3 venoms presented an insignificant thrombin-like activity. In relation to the fibrinolytic activity, San Bernardino 3 venom was the most active on fibrin plates, which was in turn neutralized by metal chelating inhibitors. These results demonstrate the differences amongst C. oreganus helleri venoms from close localities. A metalloproteinase, hellerase, was purified by anionic and cationic exchange chromatographies from San Bernardino 3 venom. Hellerase exhibited the ability to break fibrin clots in vitro, which can be of biomedically importance in the treatment of heart attacks and strokes.

[Effect of a novel fibrinolytic enzyme FA-I on thrombosis and thrombolysis]

OBJECTIVE

To study the effect of FA-I, a novel fibrinolytic enzyme isolated from the metabolite of Arthrobacter sp. DR-536, on thrombosis and thrombolysis in vivo.

METHODS

The anticoagulated blood model of mise were administered with FA-I orally. The venous thrombogenesis inhibition model of rats were administered with FA-I by intestinal route. The carotid thrombosis model of rabbits were given FA-I intravenously. The clotting time (CT), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), Euglobulin lysis time (ELT), fibrinogen (FIG) and hemorheology condition were analyzed.

RESULTS

FA-I prolonged the CT, PT, APTT and TT, and decreased ELT and FIG significantly (P < 0.05 or P < 0.01). FA-I also improved the hemorheology conditions in the rabbits.

CONCLUSION

Both intravenous injection and oral administration of FA-I are effective in thrombosis and thrombolysis. FA-I could become a pragmatic venoclysis thrombolytic drug or a peroral thrombolytic drug.

Novel benzil and isoflavone derivatives from Millettia dielsiana

The analysis of vine stem extract from MILLETTIA DIELSIANA Harms yielded a novel benzil ( 1) and five new prenylated isoflavones ( 2 - 6) together with three known isoflavones ( 7 - 10) and one known flavone ( 11), and their structures were elucidated on the basis of chemical and spectral analysis. The absolute configuration of the 3'',4''-diols in 6 was determined by observing the CD induced after addition of dimolybdenum tetraacetate in DMSO solution (Snatzke's method). Some isolates were tested for their anti-inflammatory and antithrombase activities and cytotoxicities. Compound 2, barbigerone, and genistein showed significant anti-inflammatory activity, with inhibitory ratios 59.1 %, 59.5 %, and 58.5 %, respectively, at 10 muM, while compound 4 exhibited moderate cytotoxicity.

Characterization of a novel dermatan sulfate with high antithrombin activity from ray skin (Raja radula)

INTRODUCTION

A novel dermatan sulfate (DS) from the skin of the ray Raja radula with high anticoagulant activity was identified and its monosaccharide composition and anticoagulant mode of action and potency were determined.

MATERIALS AND METHODS

The DS isolated from the ray skin was identified by chondroitinase treatment and characterized by FT-IR and (1)H NMR spectroscopy. Its anticoagulant activity was checked by activated partial thromboplastin time (aPTT), thrombin time (TT), thrombin generation (TG), heparin cofactor II (HCII) and antithrombin (AT)-mediated inhibition of thrombin. The effects on platelet activation and aggregation were investigated using flow cytometry and aggregometry, respectively.

RESULTS

Chemical backbone structures of DS from Raja radula were close to that of DS from porcine intestinal mucosa. However, (1)H NMR indicated that iduronic acid was the major hexuronic acid moiety in the ray skin DS and also suggested that the amount of 2-O-sulfonated iduronic acid was higher in comparison with mammalian DS along with the occurrence of 4-O-sulfonated N-acetylgalactosamine residues. The anticoagulant effect of the ray skin DS was mainly due to the potentiation of thrombin inhibition by HCII but also, although to a lesser extent, by AT and was higher than that of the DS standard. Moreover, it had no effect on platelet activation and aggregation induced by various agonists.

CONCLUSION

Altogether, these results indicated that DS from raja radula skin is an anticoagulant drug of interest potentially useful in anticoagulant therapy.

[Purification and characterization of fibrinolytic enzyme from Bacillus subtilis BS-26]

OBJECTIVE

Thrombolytic therapy is a safe and effective treatment for thrombotic diseases. Microorganisms are possible sources of thrombolytic drugs. We purified and characterized fibrinolytic enzyme produced by Bacillus subtilis strain BS-26.

METHODS

We examined the fibrinolytic enzyme activity by fibrin plate and purified fibrinolytic enzyme by ammonium sulfate fractional precipitation, anion-exchange chromatography on DEAE-Sepharose Fast Flow and preparative PAGE.

RESULTS

The fibrinolytic enzyme of the strain BS-26 was stable blow 50 degrees C and pH5.0-11.0, the optimal temperature was 42 degrees C and optimal pH was 9.0. Ca2+ and Mg2+ ions enhanced the fibrinolytic activity, whereas Cu2+ completely inhibited the enzyme. Phenylmethylsulfonyl fluoride (174.2 microg/mL), chicken ovomucoid (1000 microg/mL) and soybean trypsin inhibitor (1000 microg/mL) could inhibit enzyme activity, which indicated that the enzyme belonged to serine protease group. On plasminogen-free fibrin plates and plasminogen fibrin plates, the fibrinolytic activity had no obvious difference, indicating that the enzyme was a fibrinolytic enzyme which degraded fibrin directly, but not a plasminogen activator which degraded fibrin by activating plasminogen. A fibrinolytic enzyme was purified from the fermentation broth with recovery yield of 3.2%, purification factor of 41.0 fold and the specific activity 8750.0 U/mg. SDS-PAGE analysis of the purified protein showed only one band with molecular mass of 32 kDa.

CONCLUSION

A single fibrinolytic enzyme was purified, which provided the basis for large-scale production of fibrinolytic enzyme.

A non-anticoagulant heterofucan has antithrombotic activity in vivo

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.

Production & purification of a fibrinolytic enzyme (thrombinase) from Bacillus sphaericus

BACKGROUND & OBJECTIVE

Treatment of thromboembolic vascular disease has relied on anticoagulants. However, recognition that lysis of preformed fibrin could be accomplished in vivo by a process involving the conversion of inactive plasminogen to active plasmin enzyme led to an alternative enzyme-based approach. The drugs used for this therapy are called the fibrinolytic enzymes. In this study we attempted the production, purification and characterization of fibrinolytic enzyme from Bacillus sphaericus.

METHODS

The seed was prepared in nutrient yeast salt medium (NYSM) in shake flask and organism was produced in 100 l pilot fermentor. Biomass was separated by centrifugation and crude protein was prepared by ammonium sulphate precipitation. Purification was done by ion exchange chromatography using Q sepharose followed by gel filtration chromatography using Sephacryl S- 300. Molecular weight was determined through HPLC. Fibrinolytic activity was assayed by fibrin plate method.

RESULTS

The production method yielded 64 mg/l of the crude enzyme and after purification it was 6.3 mg/l. The molecular weight of the compound was 18.6 kDa.

INTERPRETATION & CONCLUSION

The enzyme exhibited similar fibrinolytic activity as that of streptokinase, on fibrin plates that were devoid of plasminogen, suggesting that its fibrinolytic action is independent of plasminogen and it is not a plasminogen activator.

Inhibition of adrenaline and adenosine diphosphate induced platelet aggregation by Lansberg's hognose pit viper (Porthidium lansbergii hutmanni) venom

The haemostatic components of venom from the genus Porthidium has been poorly studied, although it is known that severe manifestations occur when humans are envenomed, which include invasive oedema and disseminated ecchymosis. The effects of venom on blood platelets are commonly studied and are normally carried out with platelet-rich plasma (PRP). A series of crude venom dilutions was used to determine the effects of adenosine diphosphate (2 microM) and adrenaline (11 microM) induced platelet aggregation. Venom of Porthidium lansbergii hutmanni was fractioned by anionic exchange chromatography, and the fractions were also used to determine the 50% inhibition of adenosine diphosphate (ADP) and adrenaline-induced platelet aggregating dose (AD50). Crude venom has more effect in inhibiting adrenaline-induced aggregation (AD50 = 0.0043 microg) followed by the adenosine diphosphate (AD50 = 17 microg). Peaks I and II obtained by chromatography also inhibited adrenaline-induced platelet aggregation with an AD50 of 3.2 and 0.013 microg, respectively, and both peaks inhibited ADP-induced platelet aggregation with an AD50 of 10 microg. The main purpose of this work was to characterise the in vitro effects caused by P. lansbergii hutmanni crude venom and its fractions on the platelet aggregation mediated by adrenaline and ADP agonists.

Purification and characterization of a new fibrinolytic enzyme of Bacillus licheniformis KJ-31, isolated from Korean traditional Jeot-gal

Jeot-gal is a traditional Korean fermented seafood and has long been used for seasoning. We isolated 188 strains from shrimp, anchovy, and yellow corvina Jeot-gal, and screened sixteen strains that showed strong fibrinolytic activities on a fibrin plate. Among those strains, the strain that had the largest halo zone was chosen and identified as Bacillus licheniformis by using 16S rDNA sequencing and an API CHB kit. The fibrinolytic activity of Bacillus licheniformis was characterized and designated as bpKJ-31. The active component of bpKJ-31 was identified as a 37 kDa protein, designated bacillopeptidase F, by internal peptide mapping and N-terminal sequencing. The optimum activity of bpKJ-31 was shown at pH 9 and 40 degrees C, with a chromogenic substrate for plasmin. It had high degrading activity for the Bbeta-chain and Aalpha-chain of fibrin(ogen), and also acted on thrombin, but not skim milk and casein. The amidolytic activity of bpKJ-31 was inhibited by 1 mM phenylmethanesulfonyl fluoride, but 1 mM EDTA did not affect the enzyme activity, indicating that bpKJ-31 is an alkaline serine protease, like a plasmin. The bpKJ-31 showed approximately 14.3% higher fibrinolytic activity than the plasmin. These features of bpKJ-31 make it attractive as a health-promoting biomaterial.

The anti-thrombotic active constituents from Centella asiatica

The in vitro effects of a methanol extract from the aerial parts of Centella asiatica on shear-induced platelet activation and coagulation were assessed after oral administration to rats, by subjecting non-anticoagulated blood to haemostatometry. 3,5-Di-O-caffeoyl quinic acid, 1,5-di-O-caffeoyl quinic acid, 3,4-di-O-caffeoyl quinic acid, 4,5-di-O-caffeoyl quinic acid, and chlorogenic acid, together with asiaticoside, kaempferol, quercetine, kaempferol-3-O-beta-D-glucoside and quercetin-3-O-beta-D-glucoside were all isolated from the methanol extract. Amongst these, only 3,5-di-O-caffeoylquinic acid showed significant inhibition of shear-induced platelet activation and dynamic coagulation. The reactive curve of the inhibitory effect on the platelet reaction and the dynamic coagulation showed a bell-shape.

[Study of a glycoprotein from Gastrodia elata: its effects of anticoagulation and antithrombosis]

OBJECTIVE

To investigate the effects of polysaccharide 2-1 from Gastrodia elata (PGE2-1) on blood coagulation and thrombosis.

METHOD

Clotting time (CT) and bleeding time (BT) of mice were measured by glass method and tail-cutting method. Bleeding capacity (A540) was measured by cutting tail in 5 min. Plama recalcificatic time (RT) were measured in mice. Platelet aggregation was caused by adenosine diphosphate (ADP). Activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) were measured by reagent boxes. During thrombosis in vitro, their lengths, wet and dry weights were measured by instrument; wet weights of arteriovenous experimental thrombosis were measured and the impressive rates were analyzed.

RESULT

CT and BT of groups PGE2-1 (60, 120 mg x kg(-1)) were remarkably prolonged, and bleeding capacity (A540) were significantly increased (P < 0.05 or P < 0.01). RT of groups PGE2-1 (30, 60, 120 mg x kg(-1)) were remarkably prolonged, and platelet aggregation (PAG) were inhibited (P < 0.05 or P < 0.01). Human serous TT and APTT of groups PGE2-1 (10, 20, 40 mg x mL(-1)) were remarkably prolonged (P < 0.05 or P < 0.01), but the difference of effect on PT had no statistic significance. PGE2-1 (30, 60, 120 mg x kg(-1)) could make the mice obviously eliminate thrombus symptom and reduce the time of restoring independent activity (P < 0.05 or P < 0.01); thrombosis in vitro: Lengths, wet and dry weights of groups PGE2-1 (30, 60, 120 mg x kg(-1)) were significantly decreased (P < 0.05 or P < 0.01); wet weights of arteriovenous experimental thrombosis were dramatically decreased (P < 0.01), and impressive rates were respectively 32.5%, 49.0% and 61.5%.

CONCLUSION

PGE2-1 has remarkable effects of anticoagulation and antithrombosis, so it may be the main component of the isolation from G. elata in the field of antithrombosis.

Inhibition of thrombin-induced platelet aggregation using human single-chain Fv antibodies specific for TREM-like transcript-1

TREM-like transcript-1 (TLT-1) is a novel platelet membrane receptor, which has been recently characterized in mice. TLT-1 is expressed exclusively in platelets and megakaryocytes, and its expression is dramatically upregulated upon platelet activation, suggesting that it plays a unique role in hemostasis and/or thrombosis. In this study we identified and characterized highly specific human monoclonal antibodies that bind to TLT-1 by screening a naïve library of single chain Fv fragments (scFvs) displayed on filamentous phage (Thomlinson I library). These scFvs detected plate-bound TLT-1, captured soluble TLT-1, and readily reacted with cell-bound TLT-1 on transfectants and primary human platelets. Most importantly, anti-TLT-1 scFvs inhibited thrombin-mediated human platelet aggregation. This inhibition was specific for thrombin-induced aggregation and was reversible with higher doses of agonist. These data are the first to demonstrate a biological role for TLT-1 and its potential as a therapeutic target. The human scFvs isolated in this study may represent novel anti-platelet therapeutic agents.

Identification and characterization of Harobin, a novel fibrino(geno)lytic serine protease from a sea snake (Lapemis hardwickii)

A gene encoding a novel serine protease designated as Harobin is cloned and identified from a sea snake venom gland bacteriophage T7 library. It has 265 amino acids and shares 50-70% similarity to terrestrial snake serine proteases. In addition to the 12 conservative Cys, it has three more Cys residues that may contribute to its higher enzymatic stability. Harobin is expressed in Pichia pastoris and purified. Recombinant Harobin exhibits an amidolytic activity, and specifically degrades Aalpha, Bbeta-chain of fibrinogen. It functions as a defibrase both in vitro and in vivo, and reduces thrombosis. Harobin prolongs the coagulation time and the bleeding time of mice and reduces the fibrinogen levels of rats as well. Meanwhile, intravenous injection of Harobin leads to the reduction of blood pressure in SHR rats. It results from the ability of Harobin that cleaves angiotensin I and release bradykinin from plasma kininogen in vitro and in vivo. These data suggest that Harobin is a novel defibrase and has a potential to be an agent for the therapy of thrombosis and hypertension.

Inhibition of collagen, and thrombin-induced platelet aggregation by Lansberg’s hognose pit viper (Porthidium lansbergii hutmanni) venom

The Porthidium genus is represented by the P. lansbergii rozei and P. lansbergii hutmanni (Plh) subspecies in Venezuela. The venom components of these have been little studied, probably due to the low incidence of reported accidents, although acute and serious local effects such as invasive edema and disseminated ecchymosis are present during human envenonation. The aim of this work was to characterize the in vitro effects of crude P. l. hutmanni venom, and its fractions, on platelet aggregation triggered by two physiologic agonists: thrombin and collagen. The effects of thrombin and collagen were observed on a platelet-rich plasma (PRP) solution (3 x 10(5) platelets/microL) using serial dilutions of P. l. hutmanni venom (0.625-40 microg). The crude venom was fractionated by anionic exchange chromatography and two peaks obtained. Crude venom and both fractions were highly inhibitory on platelet aggregation mediated by the two agonists. The anti-aggregating dose (AD(50)) for both agonists was determined. PRP collagen-triggered aggregation was most inhibited by the crude venom (AD(50) = 0.67 microg) when compared with PRP thrombin-triggered aggregation (AD(50) = 4.92 microg). Collagen-induced aggregation was more intensely inhibited by venom than thrombin-induced aggregation. In conclusion, to specify the inhibition mechanisms involved for each of the active components in the venom from these subspecies, we must characterize and purify the inhibitors of aggregation from P. l. hutmanni venom, with the purpose of suggesting new pharmacological substances to be incorporated into the therapeutic arsenal to treat hemostatic pathologies related to high levels of platelet aggregation.

Isolation and Identification of an Endophytic Strain EJS-3 Producing Novel Fibrinolytic Enzymes

An endophytic strain EJS-3, which produces a novel fibrinolytic enzyme, was screened from root tissue of Stemona japonica (Blume) Miq, a chinese traditional medicine. This strain was identified as Paenibacillus polymyxa (DQ120522) by morphological, physiological, and biochemical tests and 16S rRNA gene sequence analysis. Two serine-type fibrinolytic enzymes with a relative molecular weight about 118 and 49 kDa, respectively, which are larger than known fibrinolytic enzymes, were found by the SDS-fibrin zymogram or by fibrin-inhibitor zymography gels. No work on P. polymyxa-producing fibrinolytic enzymes has been reported.

Isolation and partial characterization of proteins with vasodegenerative and proinflammatory properties from the egg-nests of Hylesia metabus (Lepidoptera: Saturniidae)

The Hylesia genus comprises a group of Neotropical moths ubiquitous in the Americas from Arizona to Argentina. One of the species of the Hylesia genus in Venezuela, French Guyana, and Trinidad has been identified as Hylesia metabus (Cramer 1775) (Lepidoptera: Saturniidae). In Venezuela, these moths are found in abundance in the mangrove (Avicennia spp.) swamps surrounding the Gulf of Paria and the Orinoco Delta in the eastern part of the country. During the mating season, the female adults shed copious amounts of urticating setae in the air, producing a severe papulovesicular dermatitis among the population in the affected areas. The females also use their urticating setae to protect the eggs during the hatching period. In the current study, we have isolated and partially characterized proteins with proinflammatory properties from the urticating setae in the egg-nests by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and anionic exchange-high-performance liquid chromatography (HPLC). We also have studied the biological response of the egg-nest extract and the HPLC purified fractions by inoculation in guinea pigs; and, analyzing the tissue samples by means of histopathological methods. The results of this study show that the extracted venom and HPLC purified subcomponents give rise to an intense inflammatory reaction characterized by massive infiltration of inflammatory cells, echymoses, and vascular degeneration. Chromatographic separation showed that the venom was made up of proteins having selectively vasodegenerative-fibrinolytic or proinflammatory-quimotactic properties.

A fibrinolytic enzyme from the medicinal mushroom Cordyceps militaris

In this study we purified a fibrinolytic enzyme from Cordyceps militaris using a combination of ion-exchange chromatography on a DEAE Sephadex A-50 column, gel filtration chromatography on a Sephadex G-75 column, and FPLC on a HiLoad 16/60 Superdex 75 column. This purification protocol resulted in a 191.8-fold purification of the enzyme and a final yield of 12.9 %. The molecular mass of the purified enzyme was estimated to be 52 kDa by SDS-PAGE, fibrin-zymography, and gel filtration chromatography. The first 19 amino acid residues of the N-terminal sequence were ALTTQSNV THGLATISLRQ, which is similar to the subtilisin-like serine protease PR1J from Metarhizium anisopliae var. anisopliase. This enzyme is a neutral protease with an optimal reaction pH and temperature of 7.4 and 37 degrees , respectively. Results for the fibrinolysis pattern showed that the enzyme rapidly hydrolyzed the fibrin alpha-chain followed by the gamma-gamma chains. It also hydrolyzed the beta-chain, but more slowly. The Aalpha, Bbeta, and gamma chains of fibrinogen were also cleaved very rapidly. We found that enzyme activity was inhibited by Cu2+ and Co2+, but enhanced by the additions of Ca2+ and Mg2+ ions. Furthermore, fibrinolytic enzyme activity was potently inhibited by PMSF and APMSF. This enzyme exhibited a high specificity for the chymotrypsin substrate S-2586 indicating it 's a chymotrypsin-like serine protease. The data we present suggest that the fibrinolytic enzyme derived from the edible and medicinal mushroom Cordyceps militaris has fibrin binding activity, which allows for the local activation of the fibrin degradation pathway.