Search

The present paper reports the photodegradation of a pharmaceutical pollutant, Levofloxacin, in an aqueous solution using two photocatalyst nanocomposites, g-C3N4/TiO2 and WO3/TiO2, under the influence of solar light and UV irradiation. These as-designed nano-heterostructures were synthesized using the hydrothermal method without organic templates or additives. The characterization results revealed that the used preparation method grants the purity of the prepared composites and gives a nanoscale character product. The effects of the weight ratio of g-C3N4/TiO2 and WO3/TiO2, the mass of the catalyst and the initial concentration of Levofloxacin on the photocatalytic activity were evaluated under UV light. Results showed that 5 mg/L of Levofloxacin with 20 mg of the prepared nanocomposite with a 5% weight ratio of g-C3N4 and WO3 allowed a quasi-total degradation of the pharmaceutical pollutant within only 30 min. The photocatalytic activities investigation of the prepared nanocomposites under sunlight irradiation showed that after 50 min of treatment, 66% of degradation is reached with WO3/TiO2 against 100% with g-C3N4/TiO2. The possible photocatalytic mechanism was thoroughly investigated, explaining the improved photocatalytic activity. This work demonstrates that the prepared nanocomposites' photocatalytic degradation of pharmaceutical pollutants is efficient, providing a friendly environmental strategy. [ABSTRACT FROM AUTHOR]

Cobalt dimethylphenylpiperazinium cyclotetraphosphate hexahydrate, Co[C 12 H 19 N 2 ] 2 P 4 O 12 .6H 2 O, was synthesized by a reaction between cyclotetraphosphoric acid H 4 P 4 O 12 , cobalt carbonate, and 1-(2,4-dimethylphenylpiperazine). It crystallizes in the triclinic system, space group P, with the following unit cell parameters: a = 7.336(1), b = 8.413(1), c = 14.926(2) Å, α = 87.46(1), β = 83.13(1), γ = 82.98(1)°, V = 907.3(2) Å 3 , and Z = 1. The atomic arrangement can be described as layers containing P 4 O 12 rings a and Co(H 2 O) 6 octahedra spreading in the (001) planes between which are located the dimethylphenylpiperazinium groups via H-bonds. The synthesis and characterization by X-ray diffraction, IR absorption, and thermal analysis are described. [ABSTRACT FROM AUTHOR]

Abstract: The preparation, crystal structure, TG–DTA analysis and spectroscopy investigation are reported for the 2,5-dimethoxy phenyl ammonium cyclotetraphosphate dihydrate [2,5-(CH3O)2C6H3NH3]4P4O12·2H2O. This new compound is triclinic P with unit cell dimensions: a =7.438(5)Å, b =11.841(7)Å, c =12.354(4)Å, α =96.61(4)°, β =98.35(4)°, γ =102.60(6)°, Z =1 and V =1038.0(1)Å3. Its crystal structure has been determined and refined to R =0.049, with 5128 independant reflections. The structure can be described by rows of P4O12 ring anions along the a axis; between these rows are located the organic groups, connected to them by hydrogen bonds. [Copyright &y& Elsevier]

Chemical preparation and crystal structure are given for a new cyclotetraphosphate: [3,5-(CH3)2C6H3NH3]4P4O12·3H2O. This compound is triclinic P1¯ with the following unit-cell parameters: a=8.298(3), b=8.299(3), c=17.242(7)A˚, α=97.13(3), β=102.72(3), γ=64.55(3)°, Z=1 and V=1045.2(8) A˚3. The crystal structure has been solved and refined to R=0.040 using 6086 independent reflections. The atomic arrangement can be described as layers organization. Layers built by P4O12 ring anions, ammonium groups and water molecules parallel to the plan (001), between which the organic groups are located. Characterization by X-ray diffraction, IR absorption, and thermal analysis are described. [Copyright &y& Elsevier]

The chemical preparation and crystal structure are given for a new organic-cation cyclotetraphosphate. This compound is triclinic P-1 with the following unit cell parameters: a=7.857(1) A˚, b=8.877(2) A˚, c=17.271(3) A˚, α=93.94(1)°, β=101.75(2)°, γ=103.72(1)° V=1137.0(4) A˚3, Z=1 and ρcal=1.467 g cm−3. The crystal structure has been determined and refined to R=0.037, using 6291 independent reflections. The atomic arrangement can be described by inorganic layers parallel to the (0 0 1) planes, between which the organic entities are located. [ABSTRACT FROM AUTHOR]

The synthesized pyrazolopyrimidine derivatives conjugated with selenium nanoparticles were prepared via a reaction of pyrazolone 1 with aryl-aldehyde and malononitrile or 3-oxo-3-phenylpropanenitrile in the presence ammonium acetate or pipridine using an ultrasonic bath as a modified method in the organic synthesis for such materials. The structure of the synthesized compounds was elucidated through various techniques. All the synthesized pyrazolopyrimidines were used in the synthesis of selenium nanoparticles (SeNPs). These nanoparticles were confirmed using UV-spectra, Dynamic Light scattering and (TEM) techniques. The larvicidal efficiency;of the synthesized;compounds; was investigated against some strains such as Culex pipiens;and Musca domestica larvae. Bioassay test showed pyrazolopyrimide derivatives to exhibit an acceptable larvicidal;bio-efficacy. The derivative (3) exhibited;the highest;efficiency for more than; lab strains of both species. Moreover, C. pipiens larvae were more sensitive towards the examined compounds than M. domestica. The field;strain displayed lower affinity for the 2 folds compounds. Some biochemical changes were tracked through analysis of insect main metabolites (protein, lipid and carbohydrate), in addition to measuring the changes in seven enzymes after treatment. Generally, there was a reduction in the protein, lipids and carbohydrates after treatment with all tested compounds. Moreover, a decrement was noticed for acetylcholine esterase and glutathione;S-transferase; enzymes. There was an increment in the acid;phosphatase; and alkaline phosphatase. In addition, there was elevation in Phenoloxidase level but it noticed the declination in both Cytochrome P450 and Ascorbate peroxidase activity after treatment both flies with derivatives of selenium-nanoparticles in both lab and field strain. Generally, the experiments carried out indicate that antioxidant and detoxification enzymes may play a significant role in mechanism of action of our novel nanocompounds. The cytotoxicity of the synthesized compounds and conjugated with SeNPs showed enhanced compatibility with human normal fibroblast cell line (BJ1) with no toxic effect., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

With the goal of developing a high-performance organic solar cell, nine molecules of A 2 -D-A 1 -D-A 2 type are originated in the current investigation. The optoelectronic properties of all the proposed compounds are examined by employing the DFT approach and the B3LYP functional with a 6-31G (d, p) basis set. By substituting the terminal moieties of reference molecule with newly proposed acceptor groups, several optoelectronic and photovoltaic characteristics of OSCs have been studied, which are improved to a significant level when compared with reference molecule, i.e., absorption properties, excitation energy, exciton binding energy, band gap, oscillator strength, electrostatic potential, light-harvesting efficiency, transition density matrix, open-circuit voltage, fill factor, density of states and interaction coefficient. All the newly developed molecules (P1-P9) have improved λ max , small band gap, high oscillator strengths, and low excitation energies compared to the reference molecule. Among all the studied compounds, P9 possesses the least binding energy (0.24 eV), P8 has high interaction coefficient (0.70842), P3 has improved electron mobility due to the least electron reorganization energy (λ e  = 0.009182 eV), and P5 illustrates high light-harvesting efficiency (0.7180). P8 and P9 displayed better V oc results (1.32 eV and 1.33 eV, respectively) and FF (0.9049 and 0.9055, respectively). Likewise, the phenomenon of charge transfer in the PTB7-Th/P1 blend seems to be a marvelous attempt to introduce them in organic photovoltaics. Consequently, the outcomes of these parameters demonstrate that adding new acceptors to reference molecule is substantial for the breakthrough development of organic solar cells (OSCs)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Minimizing the energy loss and improving the open circuit voltage of organic solar cells is still a primary concern for scientists working in this field. With the aim to enhance the photovoltaic performance of organic solar cells by minimizing energy loss and improving open circuit voltage, seven new acceptor molecules (LC1-LC7) are presented in this work. These molecules are designed by modifying the terminal acceptors of pre-existed "LC81" molecule based on an indacinodithiophene (IDT) fused core. The end-group modification approach is very fruitful in ameliorating the efficacy and optoelectric behavior of OSCs. The newly developed molecules presented remarkable improvements in performance-related parameters and optoelectronic properties. Among all designed molecules, LC7 exhibited the highest absorption maxima (λ max  = 869 nm) with the lowest band-gap (1.79 eV), lowest excitation energy (E x  = 1.42 eV), lowest binding energy, and highest excited state lifetime (0.41 ns). The newly designed molecules LC2, LC3, and LC4 exhibited remarkably improved Voc that was 1.84 eV, 1.82 eV, and 1.79 eV accordingly, compared to the LC81 molecule with V oc of 1.74 eV LC2 molecule showed significant improvement in fill factor compared to the previously presented LC81 molecule. LC2, LC6, and LC7 showed a remarkable reduction in energy loss by showing E loss values of 0.26 eV, 0.18 eV, and 0.25 eV than LC81 molecule (0.37 eV). These findings validate the supremacy of these developed molecules (especially LC2) as potential components of future OSCs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Improving the charge mobility and optoelectronic properties of indacenodithiophene - based small molecule acceptors is a key challenge to improving overall efficiency. In this current research, seven newly designed molecules ( DT1-DT7 ) comprising the indacenodithiophene - based core are presented to tune energy levels, enhance charge mobility, and improve the photovoltaic performance of IDTV-ThIC molecules via density functional theory. All the molecules were designed by end-capped modification by substituting terminal acceptors of IDTV-ThIC with strong electron-withdrawing moieties. Among all the examined structures, DT1 has proved itself a superior molecule in multiple aspects, including higher λ max in chloroform (787 nm) and gaseous phase (727 nm), narrow band gap (2.16 eV), higher electron affinity (3.31 eV), least excitation energy (1.57 eV), and improved charge mobility due to low reorganization energy and higher excited state lifetime (2.37 ns) when compared to the reference (IDTV-ThIC) and other molecules. DT5 also showed remarkable improvement in different parameters, such as the lowest exciton binding energy (0.41 eV), leading to easier charge moveability. The improved open-circuit voltage of DT4 and DT5 makes them proficient molecules exhibiting the charge transfer phenomenon. The enlightened outcomes of these molecules can pave a new route to develop efficient organic solar cell devices using these molecules, especially DT1 , DT4 , and DT5 ., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

In the current study, six nonfullerene small acceptor molecules were designed by end-group modification of terminal acceptors. Density functional theory calculations of all designed molecules were performed, and optoelectronic properties were computed by employing different functionals. Every constructed molecule has a significant bathochromic shift in the maximum absorption value (λ max ) except AM6 . AM1 - AM4 molecules represented a narrow band gap ( E g ) and low excitation energy values. The AM1 - AM4 and AM6 molecules have higher electron mobility. Comparing AM2 to the reference molecule reveals that AM2 has higher hole mobilities. Compared to the reference molecule, all compounds have excellent light harvesting efficiency values compared to AM1 and AM2 . The natural transition orbital investigation showed that AM5 and AM6 had significant electronic transitions. The open-circuit voltage ( V oc ) values of the computed molecules were calculated by combining the designed acceptor molecules with PTB7-Th. In light of the findings, it is concluded that the designed molecules can be further developed for organic solar cells (OSCs) with superior photovoltaic abilities., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

The competence of organic solar cells (OSCs) could be enhanced by improving the light absorption capabilities as well as the open-circuit voltage (V oc ) of utilized molecules. To upgrade overall functionality of OSCs, seven new molecules were designed in this work using an end-cap alteration technique on Quinoxaline fused core-based non-fullerene acceptor (Qx-2) molecule. This technique is known to be quite advantageous in terms of improvement of the effectiveness and optoelectrical behavior of various OSCs. Critical parameters like the absorption maximum, frontier molecular orbitals, excitation energy, exciton binding energy, V oc , and fill factor of molecules were considered for the molecules thus designed. All newly designed molecules showed outstanding improvement in optoelectronic as well as performance-related properties. Out of all scrutinized molecules, Q1 exhibited highest wavelength of absorption peak (λ max  = 779 nm) with the reduced band gap (1.90 eV), least excitation energy (E x  = 1.59 eV), along with the highest dipole moment (17.982950 D). Additionally, the newly designed compounds Q4, Q5, and Q6 exhibited significantly improved V oc s that were 1.55, 1.47, and 1.50 eV accordingly, as compared to the 1.37 eV of Qx-2 molecule. These molecules also showed remarkable improvement in fill factor attributed to direct correspondence of V oc with it. Inclusively, these results support the superiority of these newly developed molecules as prospective constituents of upgraded OSCs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Non-fused ring-based OSCs are an excellent choice, which is attributed to their low cost and flexibility in applications. However, developing efficient and stable non-fused ring-based OSCs is still a big challenge. In this work, with the intent to increase V oc for enhanced performance, seven new molecules derived from a pre-existing A-D-A type A3T-5 molecule are proposed. Different important optical, electronic and efficiency-related attributes of molecules are studied using the DFT approach. It is discovered that newly devised molecules possess the optimum features required to construct proficient OSCs. They possess a small band gap ranging from 2.22-2.29 eV and planar geometries. Six of seven newly proposed molecules have less excitation energy, a higher absorption coefficient and higher dipole moment than A3T-5 in both gaseous and solvent phases. The A3T-7 molecule exhibited the maximum improvement in optoelectronic properties showing the highest λ max at 697 nm and the lowest E x of 1.77 eV. The proposed molecules have lower ionization potential values, reorganization energies of electrons and interaction coefficients than the A3T-5 molecule. The V oc of six newly developed molecules is higher ( V oc ranging from 1.46-1.72 eV) than that of A3T-5 ( V oc = 1.55 eV). Similarly, almost all the proposed molecules except W6 exhibited improvement in fill factor compared to the A3T-5 reference. This remarkable improvement in efficiency-associated parameters ( V oc and FF) proves that these molecules can be successfully used as an advanced version of terthiophene-based OSCs in the future., Competing Interests: The Authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

In the present investigation, we use a dual computational approach (at single molecular and solid-state levels) to explore the optoelectronic and nonlinear optical (NLO) properties of cross-shaped derivatives. The solid-state electronic band structures of the compounds 1-3 (the derivatives of tetracarboxylic acid in cross-shaped having the core of benzene (1), pyrazinoquinoxaline (2), and tetrathiafulvalene (3)) are calculated. The calculated band gaps for compounds 1-2 are found to be direct bad gaps and compound 3 to be indirect bad gap with energy gaps of 2.749, 1.765, and 0.875 eV, respectively. The important optical properties including refractive index, absorption coefficients, loss functions, and extinction coefficient of these semiconductors are calculated at bulk level to seek their potential applications as efficient optoelectronic materials. Additionally, we use the Lorentz approximation to calculate the third-order NLO susceptibilities of compounds 1-3 using the molecular hyperpolarizability and solid-state parameters. The calculated third-order NLO susceptibilities of compounds 1-3 are found to be 6.92 × 10 -12 , 64.0 × 10 -12 , and 26.3 × 10 -12  esu, respectively. Thus, the present study not only provides a way to connect the calculated third-order molecular NLO polarizability to NLO susceptibilities for compounds 1-3 through Lorentz approximation but also highlights the importance of central core modifications on their NLO susceptibilities.

Background: The resistance of melanoma cells to cisplatin restricts its clinical use. Therefore, the search for novel tumor inhibitors and effective combination treatments that sensitize tumor cells to this drug are still needed. We purified macrovipecetin, a novel heterodimeric C-type lectin, from Macrovipera lebetina snake venom and investigated its anti-tumoral effect on its own or combined with cisplatin, in human melanoma cells., Methods: Biochemical characterization, in vitro cells assays such as viability, apoptosis, adhesion, migration, invasion, Western blotting and in silico analysis were used in this study., Results: Macrovipecetin decreased melanoma cell viability 100 times more than cisplatin. Interestingly, when combined with the drug, macrovipecetin enhanced the sensitivity of SK-MEL-28 cells by augmenting their apoptosis through increased expression of the apoptosis inducing factor (AIF) and activation of ERK 1/2 , p38, AKT and NF-κB. Moreover, macrovipecetin alone or combined with cisplatin induced the expression of TRADD, p53, Bax, Bim and Bad and down-regulated the Bcl-2 expression and ROS levels in SK-MEL-28 cells. Interestingly, these treatments impaired SK-MEL-28 cell adhesion, migration and invasion through modulating the function and expression of αvβ3 integrin along with regulating E-cadherin, vimentin, β-catenin, c-Src and RhoA expression. In silico study suggested that only the α chain of macrovipecetin interacts with a region overlapping the RGD motif binding site on this integrin., Conclusions: We validated the antitumor effect of macrovipecetin when combined, or not, with cisplatin on SK-MEL-28 cells., General Significance: The presented work proposes the potential use of macrovipecetin and cisplatin in combination as an effective anti-melanoma treatment., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The synthesis and the crystal structure of a new halide-bridged polymer, namely catena -poly[bis-(1,2,3-benzotriazolium) [[tetra-chlorido-bis-muth(III)]-μ-chlorido] dihydrate], {(C 6 H 6 N 3 ) 2 [BiCl 5 ]·2H 2 O} n are reported. The structure comprises polyanionic zigzag chains of formula [(BiCl 5 ) 2- ] n running along the c- axis direction. The 1,2,3-benzotriazolium cations are linked between these polymer chains, via the water mol-ecules, giving rise to left- and right-handed helical chains. Hirshfeld surface analysis and fingerprint plots were used to decode the inter-molecular inter-actions in the crystal network and determine the contribution of the component units for the construction of the three-dimensional architecture.

Lebein, is an heterodimeric disintegrin isolated from Macrovipera lebetina snake venom that was previously characterized as an inhibitor of ADP-induced platelet aggregation. In this study, we investigated the effect of Lebein on the p53-dependent growth of human colon adenocarcinoma cell lines. We found that Lebein significantly inhibited LS174 (p53wt), HCT116 (p53wt), and HT29 (p53mut) colon cancer cell viability by inducing cell cycle arrest through the modulation of expression levels of the tumor suppression factor p53, cell cycle regulating proteins cyclin D1, CDK2, CDK4, retinoblastoma (Rb), CDK1, and cyclin-dependent kinase inhibitors p21 and p27. Interestingly, Lebein-induced apoptosis of colon cancer cells was dependent on their p53 status. Thus, in LS174 cells, cell death was associated with PARP cleavage and the activation of caspases 3 and 8 while in HCT116 cells, Lebein induced caspase-independent apoptosis through increased expression of apoptosis inducing factor (AIF). In LS174 cells, Lebein triggers the activation of the MAPK ERK1/2 pathway through induction of reactive oxygen species (ROS). It also decreased cell adhesion and migration to fibronectin through down regulation of α5β1 integrin. Moreover, Lebein significantly reduced the expression of two angiogenesis stimulators, Vascular Endothelial Growth Factor (VEGF) and Neuropilin 1 (NRP1). It inhibited the VEGF-induced neovascularization process in the quail embryonic CAM system and blocked the development of human colon adenocarcinoma in nude mice. Overall, our work indicates that Lebein may be useful to design a new therapy against colon cancer. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Melanoma, the most threatening form of skin cancer, has a very poor prognosis and is characterized by its very invasive and chemoresistant properties. Despite the recent promising news from the field of immunotherapy, there is an urgent need for new therapeutic approaches that are free of resistance mechanisms and side effects. Anti-neoplasic properties have been highlighted for different disintegrins from snake venom including Lebein; however, the exact effect of Lebein on melanoma has not yet been defined. In this study, we showed that Lebein blocks melanoma cell proliferation and induces a more differentiated phenotype with inhibition of extracellular signal-regulated kinase (ERK) phosphorylation and microphthalmia-associated transcription factor (MITF) overexpression. Melanoma cells became detached but were less invasive with upregulation of E-cadherin after Lebein exposure. Lebein induced a caspase-independent apoptotic program with apoptosis inducing factor (AIF), BCL-2-associated X protein (BAX) and Bim overexpression together with downregulation of B-cell lymphoma-2 (BCL-2). It generated a distinct response in reactive oxygen species (ROS) generation and p53 levels depending on the p53 cell line status (wild type or mutant). Therefore, we propose Lebein as a new candidate for development of potential therapies for melanoma.

We report the chemical composition and anti- Leishmania and antioxidant activity of Artemisia campestris L. and Artemisia herba - alba Asso. essential oils (EOs). Our results showed that these extracts exhibit different antioxidant activities according to the used assay. The radical scavenging effects determined by DPPH assay were of IC 50 = 3.3 mg/mL and IC 50 = 9.1 mg/mL for Artemisia campestris and Artemisia herba - alba essential oils, respectively. However, antioxidant effects of both essential oils, determined by ferric-reducing antioxidant power (FRAP) assay, were in the same range (2.3 and 2.97 mg eq EDTA/g EO, resp.), while the Artemisia herba - alba essential oil showed highest chelating activity of Fe 2+ ions (27.48 mM Fe 2+ ). Interestingly, we showed that both EOs possess dose-dependent activity against Leishmania infantum promastigotes with IC 50 values of 68  μ g/mL and 44  μ g/mL for A. herba - alba and A. campestris , respectively. We reported, for the first time, that antileishmanial activity of both EOs was mediated by cell apoptosis induction and cell cycle arrest at the sub-G0/G1 phase. All our results showed that EOs from A. herba - alba and A. campestris plants are promising candidates as anti- Leishmania medicinal products.

Coronary endothelial dysfunction is involved in cardiac ischemia-reperfusion (IR) injury. Vascular endothelial growth factor (VEGF) activates endothelial cells and exerts cardioprotective effects in isolated hearts. The recently discovered viper venom protein called increasing capillary permeability protein (ICPP) exerts VEGF-like effects in endothelial cells. We examined whether VEGF or ICPP can influence IR outcome in vivo in mice. Dosages of VEGF and ICPP were determined by preliminary blood pressure study. In IR, both the proteins administered intravenously at reperfusion reduced infarct size (IS) by 57% for VEGF and 52% for ICPP (P < 0.01). Pretreatment with a selective VEGFR2 receptor antagonist abolished the reduction in IS. VEGF and ICPP induced ERK phosphorylation in the myocardium. IR triggered mitochondrial pore opening and impaired mitochondrial respiratory function. These effects of IR were prevented by VEGF or ICPP, which increased mitochondrial calcium retention capacity by 37% compared with saline (P < 0.05) and improved mitochondrial respiratory function (by 71% and 65%, respectively for state 3, and 51% and 38% for state 4, P < 0.01 for VEGF). Thus, intravenous administration of VEGF or ICPP at reperfusion largely reduces IS in IR, through stimulation of VEGFR2 receptors. This effect is mediated, at least in part, by improvement of IR-induced mitochondrial dysfunction.

The Vascular Endothelial Growth Factor "VEGF" plays a pivotal role in the stimulation of angiogenesis. The VEGF isoforms (A-D) and PlGF act in a coordinate fashion to develop the vascular network. Numerous proteins closely related in structure and function to VEGF-A have been reported and were grouped in the VEGF family. Some predators make use of VEGF-like molecules with devastating results for their prey. VEGF-E, investigated in 1994, is encoded by the parapoxvirus (Orf virus). VEGF-F is a common term designating molecules which were isolated from snake venom (also known as svVEGF). These proteins are disulphide-linked homodimers of 110 amino acids each and have a molecular weight of approximately 25 kDa. Their primary structures show approximately 50% identity to VEGF-A. However, unlike VEGF-A, they do not contain any N-linked glycosylation sites. They interact with heparin but have a different binding domain from that of VEGF-A. Among species, these svVEGFs vary extensively in amino acid sequences and in receptor-binding specificities towards endogenous VEGF receptors. Understanding the properties that determine the specificity of these interactions could improve our knowledge of the VEGF-receptor interactions. This knowledge is essential to the development of new drugs in angiogenesis. This knowledge is essential to the development of new drugs in angiogenesis.

Increased vascular permeability and vasodilation are responses usually elicited by snake envenomation. In this report, we isolated from Macroviperalebetina venom two protein groups designated IC1 (Increasing Capillary1) and IC2 based on their activities on capillary permeability. Mass spectrometry analysis showed that IC1 contained four major proteins of 23,650, 24,306, 24,589 and 24,718Da, whereas IC2 contained three major proteins of 25,101, 25,194 and 25,298Da. N-terminal amino-acid sequencing revealed that IC1 and IC2 belong to the snake venom VEGF (svVEGF) family. IC1 and IC2 had a marked specificity for VEGFR-2, with affinities in the nanomolar range. Interestingly, they also bind to NRP1 and NRP2, with affinities in the micromolar range. This is the first report demonstrating that M. lebetina encodes several distinct svVEGFs, endowed with a capacity to interact with neuropilins. IC1 and IC2 could be valuable tools to understand the molecular properties of angiogenic factors and their receptors.

The partial sequence of the increasing capillary permeability protein (ICPP) purified from Vipera lebetina venom revealed a strong homology to vascular endothelial growth factor (VEGF)-A. We now report its complete amino acid sequence determined by Edman degradation and its biological effects on mouse and human vascular endothelial cells. ICPP is a homodimeric protein linked by cysteine disulfide bonds of 25115 Da revealed by mass spectrometry. Each monomer is composed of 110 amino acids including eight cysteine residues and a pyroglutamic acid at the N-terminal extremity. ICPP shares 52% sequence identity with human VEGF but lacks the heparin binding domain and Asn glycosylation site. Besides its strong capillary permeability activity, ICPP was found to be a potent in vitro angiogenic factor when added to mouse embryonic stem cells or human umbilical vein endothelial cells. ICPP was found to be as potent as human VEGF165 in activating p42/p44 MAPK, in reinitiation of DNA synthesis in human umbilical vein endothelial cells, and in promoting in vitro angiogenesis of mouse embryonic stem cells. All these biological actions, including capillary permeability in mice, were fully inhibited by 1 microm of a new specific VEGF receptor tyrosine kinase inhibitor (ZM317450) from AstraZeneca that belongs to the anilinocinnoline family of compounds. Indeed, up to a 30 times higher concentration of inhibitor did not affect platelet-derived growth factor, epidermal growth factor, FGF-2, insulin, alpha-thrombin, or fetal calf serum-induced p42/p44 MAPK and reinitiation of DNA synthesis. Therefore, we conclude that this venom-derived ICPP exerts its biological action (permeability and angiogenesis) through activation of VEGF receptor signaling (VEGF-R2 and possibly VEGF-R1).