Location of competitive facilities: a comprehensive review and future research agenda

Purpose

The research in competitive facility location (CFL) is quite dynamic, both from a problem formulation and an algorithmic point of view. Research direction has changed immensely over the years to address various competitive challenges. This study aims to explore CFL literature to highlight these research trends, important issues and future research opportunities.

Design/methodology/approach

This study utilises the Scopus database to search for related CFL models and adopts a five-step systematic approach for the review process. The five steps involve (1) Article Identification and keyword selection, (2) Selection criteria, (3) Literature review, (4) Literature analysis and (5) Research studies.

Findings

The paper presents a comprehensive review of CFL modelling efforts from 1981 to 2021 to provide a depth study of the research evolution in this area. The published articles are classified based on multiple characteristics, including the type of problem, type of competition, game-theoretical approaches, customer behaviour, decision space, type of demand, number of facilities, capacity and budget limitations. The review also highlights the popular problem areas and dedicated research in the respective domain. In addition, a second classification is also provided based on solution methods adopted to solve various CFL models and real-world case studies.

Originality/value

The paper covers 40 years of CFL literature from the perspective of the problem area, CFL characteristics and the solution approach. Additionally, it introduces characteristics such as capacity limit and budget constraint for the first time for classification purposes.

Critical Success Factors to Establish 5G Network in Smart Cities

In order to increase and develop overall performance of Modern Network Grids in Smart Cities of India with acceptable levels of security and privacy, the internal and external factors which substantially affect the performance of network grids in Smart Cities without jeopardizing privacy and security issues are needed to be identified. Besides, the interdependencies of these critical success factors are needed to be realized clearly. This paper seeks to identify these critical factors and also takes a sincere attempt to ascertain the main driving forces among these critical success factors and to ascertain inter-relationship among the CSFs. These factors here have been identified by the help of three reliable instruments which are questionnaire based survey, brainstorming and finally consolidation by Principal Component Analysis (PCA). A total of 16 critical success factors eventually have been detected by the help of PCA and finally a pragmatic structure of inter-relationship among the CSFs been developed by the application of Interpretive Structural Model (ISM).

Comparison of diagnostic tests for the detection of bovine brucellosis in the natural cases of abortion

Rapid and precise diagnosis in natural field cases of bovine abortion caused by Brucella abortus warrants the use of the most sensitive and reliable diagnostic methods. In the present study, bacterial isolation, serology, gross, histopathology, immunohistochemistry and polymerase chain reaction technique(s) were applied. Sero-prevalence studies showed the rate of 28.86% positive cases using the competitive ELISA. Histopathological changes were mainly seen in the placenta, fetal lungs, kidney, liver and spleen. Immunohistochemical (IHC) staining of Brucella spp. was evident as brown, finely granular intracytoplasmic staining in trophoblasts of placental sections and in section(s) of liver, lung, kidney and spleen. Twenty-eight out of the 103 samples (17 from stomach contents, 3 from placental cotyledons, 2 from vaginal discharges and 6 from pooled fetal tissues) produced 193 bp amplicon specific for Brucella genus. Moreover, the species-specific primers amplified a 498 bp amplicon which corresponded to B. abortus. Comparison of diagnostic tests revealed PCR and IHC provide a reliable test for the diagnosis of bovine brucellosis in aborted fetal tissue and placental cotyledons whereas serology is most important for detection of Brucella positive animals in a herd.

Evaluation of factors contributing to excessive nitrate accumulation in fodder crops leading to ill-health in dairy animals

A study was conducted to estimate nitrate content in commonly used fodder crops, viz., berseem (Trifolium alexandrinum), bajra (Pennisetum glaucum), maize (Zea mays), oats (Avena sativa), sorghum (Sorghum vulgare) and toriya (Brassica napus), collected from the fields of different villages of Punjab and farms of the university, and to evaluate the factors associated with nitrate accumulation in these crops. The nitrate level was highest in sorghum on dry matter basis, followed by oats and toriya, berseem, maize and bajra. The nitrate content was also determined in fodder samples harvested from young and mature stages and in different parts of plants. The stem part of forages had higher content than leaves; however, concentrations were low in mature crops as compared to immature ones. The environmental and soil factors associated with it are discussed and correlated with the experimental findings.

Citizens’ Adoption of Pay-to-use E-Government Services

Evidence exists that citizens’ demand for pay-to-use e-government services is highly price-elastic. But research on citizens’ adoption of e-government remains almost entirely pre-occupied with contexts wherein it is implicit that citizens would not face any monetary cost implications. The fact that Technology Acceptance model (TAM) and Perceived Characteristics of Innovating (PCI) do not factor in potential adopters’ monetary cost perceptions is a plausible reason for such bias in research efforts. The paper posits a model wherein the value perceived by a citizen in government-to-citizen (G2C) online channel, and traditional public service delivery channel are antecedents of his or her intention to use the online channel. The model was tested in the context of the rail ticketing service of Indian Railways (a Department of India’s federal government). Results support the hypothesized paths, and offer useful managerial guidance to encourage citizens’ adoption. The paper discusses the prospect of certain adverse consequences for public administration and citizens, which could be linked to e-government and user charges, and ways to mitigate them. Research implications are also discussed.

Identifying Factors of Integration for an Interoperable Government Portal

Interoperability is an important pre-condition for achieving higher stages of e-government and further ensures that a one stop portal will become a reality. Interoperability results from vertical and horizontal integration. The question arises: How can the level of interoperability and degree of integration be ascertained? This paper suggests a framework. It begins by identifying critical factors necessary for the successful adoption of interoperability technology along three dimensions of integration—process integration, communication integration, and data integration. Factors are formed from a literature review and discussions with webmasters and IT professionals working on portal development in various government departments of India. These factors are useful in further evaluation across the three dimensions and locate the position of a government portal in a technology adoption space. It is then possible to ascertain a portal’s current level of integration sophistication.

Resveratrol, an activator of SIRT1, upregulates sarcoplasmic calcium ATPase and improves cardiac function in diabetic cardiomyopathy

Reduced sarcoplasmic calcium ATPase (SERCA2a) expression has been shown to play a significant role in the cardiac dysfunction in diabetic cardiomyopathy. The mechanism of SERCA2a repression is, however, not known. This study was designed to examine the effect of resveratrol (RSV), a potent activator of SIRT1, on cardiac function and SERCA2a expression in chronic type 1 diabetes. Adult male mice were injected with streptozotocin (STZ) and fed with either a regular diet or a diet enriched with RSV. STZ administration produced progressive decline in cardiac function, associated with markedly reduced SERCA2a and SIRT1 protein levels and increased collagen deposition; RSV treatment to these mice had a tremendous beneficial effect both in terms of improving SERCA2a expression and on cardiac function. In cultured cardiomyocytes, RSV restored SERCA2 promoter activity, which was otherwise highly repressed in high-glucose media. Protective effects of RSV were found to be dependent on its ability to activate Silent information regulator (SIRT) 1. In cardiomyocytes, overexpression of SIRT1 was found sufficient to activate SERCA2 promoter in a dose-dependent manner. In contrast, pretreatment of cardiomyocytes with SIRT1 antagonist, splitomycin, blocked these beneficial effects of RSV. In addition, SIRT1 knockout (+/-) mice were also found to be more sensitive to STZ-induced decline in SERCA2a mRNA. The data demonstrate that, in chronic diabetes, 1) the enzymatic activity of cardiac SIRT1 is reduced, which contributes to reduced expression of SERCA2a and 2) through activation of SIRT1, RSV enhances expression of SERCA2a and improves cardiac function.

A new coumarin from the fruits of Coutarea hexandra

A new 5-O-beta-D-glucopyranosyl-4-(4-hydroxyphenyl)-7-methoxy-2H-chromen-2-one (1), together with four known compounds, one coumarin, 5-O-beta-D-galactopyranosyl-4-(4-hydroxyphenyl)-7-methoxy-2H-chromen-2-one (2) and three cucurbitacins, 23,24-dihydrocucurbitacin F (3), 23,24-dihydro-25-acetylcucurbitacin F (4) and 2-O-beta-D-glucopyranosyl-23,24-dihydrocucurbitacin F (5) have been isolated and characterised from the ethanol extract of Coutarea hexandra fruits. Their structures have been established by spectroscopic analysis (NMR and MS). Interpretation of the HMQC, HMBC, COSY-45 and NOESY experiments permitted us to establish stereochemistry of the natural products. All compounds were tested in cytotoxicity assays against the breast (MCF-7), lung (H-460), and central nervous system (SF-268) human cancer cell lines.

3-Farnesyl-2-hydroxybenzoic acid is a new anti-Helicobacter pylori compound from Piper multiplinervium

A new prenylated salicylic acid derivative, 3-farnesyl-2-hydroxy benzoic acid (1), was isolated from the leaves of Piper multiplinervium C. DC. (Piperaceae). It showed anti-Helicobacter pylori activity (MIC 37.5 microg/ml) and antimicrobial activity at MICs between 2.5 and 5 microg/ml against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Mycobacterium smegmatis, Pseudomonas aeruginosa and Candida albicans. Its structure was elucidated by means of MS, 1H and 13C NMR. The ethnomedical claim of Piper multiplinervium to treat stomach aches by the Kuna Indians of Panama may be justified by anti-Helicobacter pylori activity of its MeOH extract.

New prenylated benzoic acid derivatives of Piper hispidum

Three new 4-hydroxy-benzoic acid derivatives, 4-methoxy-3,5-bis-(3-hydroxy-3-methyl-1-butenyl)benzoate, 3-hydroxy-2-(1-hydroxy-1-methylethyl)-2,3-dihydrobenzofuran-5-carboxylic acid, and 3-hydroxy-2-(1-hydroxy-1-methylethyl)-2,3-dihydrobenzofuran-5-carboxylic acid methyl ester together with eight known compounds, have been isolated from the stems of Piper hispidum. Their structures were elucidated by a detailed spectroscopic analysis. In addition, the cytotoxicity of seven isolated compounds has been evaluated, revealing a moderate activity for three derivatives of dillapiole.

Medical ethnobotany of the Teribes of Bocas del Toro, Panama

Ethnomedical uses of 108 medicinal plant species, belonging to 52 families, 89 genera, used by the Teribe Amerindians of Bocas del Toro Province in Panama, along with their socio-cultural practices are reported here. The methods of administration of the herbal remedies, the plant parts used, their families and local names are also documented. The recorded medicinal plants were used mainly for fever, various type of pain and inflammation. The potential value of 26 plants and their traditional uses was elucidated through literature search.

Evaluation of bioactive saponins and triterpenoidal aglycons for their binding properties on human endothelin ETA and angiotensin AT1 receptors

Different types of triterpenes including saponins and aglycons were evaluated for their ability to inhibit [3H] BQ-123 and [3H] angiotensin II binding to the human endothelin 1 ETA and angiotensin II AT1 receptors, respectively. Selectivity for only one of the two receptors was exhibited by asiatic acid and its saponins (ETA) and oleanolic acid (AT1). To a lesser extent betulinic acid, beta-amyrin and friedelin also showed selectivity for the ETA receptor. To address the question whether the effect of saponins on cell membranes might interfere with the normal binding of specific radioligands to their receptors, the activity of saponins with different haemolytic properties were compared. Highly haemolytic saponins such as alpha-hederin and beta-escine showed partial (60%) inhibition of radioligand-binding to the ETA receptor and complete inhibition (100%) to the AT1 receptor. Moreover, the haemolytically inactive kryptoescine, at the same concentration, caused complete inhibiton of radioligand-binding to both receptors, indicating that inhibition of receptor binding was not related to the membrane-interacting properties of saponins.

In vitro cytotoxicity of 11 Panamanian plants

Thirty-five crude extracts from 11 Panamanian plants, distributed in 10 genera and five families, were evaluated for their in vitro cytotoxicity. Four extracts exhibited an inhibition of cellular growth at IC(50) values lower than 25 microg/ml which was considered a significant activity.

Andinermals A-C, antiplasmodial constituents from Andira inermis

Bioassay-guided fractionation of the leaves from Andira inermis was undertaken as part of a screening program to verify the traditional use of herbal remedies against malaria. Among the isolated phenolic compounds three novel 2-arylbenzofuran-3-carbaldehydes, andinermal A-C, were obtained together with a new flavanonol glycoside, taxifolin-3-O-(3"-O-trans-cinnamoyl)-alpha-L-rhamnopyranoside.

Peroxynitrite causes endothelial cell monolayer barrier dysfunction

Nitric oxide (.NO) attenuates hydrogen peroxide (H(2)O(2))-mediated barrier dysfunction in cultured porcine pulmonary artery endothelial cells (PAEC) (Gupta MP, Ober MD, Patterson C, Al-Hassani M, Natarajan V, and Hart, CM. Am J Physiol Lung Cell Mol Physiol 280: L116-L126, 2001). However,.NO rapidly combines with superoxide (O) to form the powerful oxidant peroxynitrite (ONOO(-)), which we hypothesized would cause PAEC monolayer barrier dysfunction. To test this hypothesis, we treated PAEC with ONOO(-) (500 microM) or 3-morpholinosydnonimine hydrochloride (SIN-1; 1-500 microM). SIN-1-mediated ONOO(-) formation was confirmed by monitoring the oxidation of dihydrorhodamine 123 to rhodamine. Both ONOO(-) and SIN-1 increased albumin clearance (P < 0.05) in the absence of cytotoxicity and altered the architecture of the cytoskeletal proteins actin and beta-catenin as detected by immunofluorescent confocal imaging. ONOO(-)-induced barrier dysfunction was partially reversible and was attenuated by cysteine. Both ONOO(-) and SIN-1 nitrated tyrosine residues, including those on beta-catenin and actin, and oxidized proteins in PAEC. The introduction of actin treated with ONOO(-) into PAEC monolayers via liposomes also resulted in barrier dysfunction. These results indicate that ONOO(-) directly alters endothelial cytoskeletal proteins, leading to barrier dysfunction.

Five new prenylated stilbenes from the root bark of Lonchocarpus chiricanus

Besides the known compounds longistylines C (1), D (2), and 3,5-dimethoxystilbene (5), five new prenylated stilbenes, named chiricanines A--E (3, 4, 6--8), have been isolated from the root bark of Lonchocarpus chiricanus. Their structures were resolved on the basis of spectrometric methods including (1)H, (13)C, and 2D NMR experiments and mass spectrometry. Compound 3 was the only prenylated stilbene to demonstrate antifungal effects against Cladosporium cucumerinum. Four of the isolated compounds showed toxic properties against larvae of the yellow fever-transmitting mosquito Aedes aegypti. Compound 5 was found to be as potent as rotenone in larvicidal dilution tests.

Physical interaction between the MADS box of serum response factor and the TEA/ATTS DNA-binding domain of transcription enhancer factor-1

Serum response factor is a MADS box transcription factor that binds to consensus sequences CC(A/T)(6)GG found in the promoter region of several serum-inducible and muscle-specific genes. In skeletal myocytes serum response factor (SRF) has been shown to heterodimerize with the myogenic basic helix-loop-helix family of factors, related to MyoD, for control of muscle gene regulation. Here we report that SRF binds to another myogenic factor, TEF-1, that has been implicated in the regulation of a variety of cardiac muscle genes. By using different biochemical assays such as affinity precipitation of protein, GST-pulldown assay, and coimmunoprecipitation of proteins, we show that SRF binds to TEF-1 both in in vitro and in vivo assay conditions. A strong interaction of SRF with TEF-1 was seen even when one protein was denatured and immobilized on nitrocellulose membrane, indicating a direct and stable interaction between SRF and TEF-1, which occurs without a cofactor. This interaction is mediated through the C-terminal subdomain of MADS box of SRF encompassing amino acids 204-244 and the putative 2nd and 3rd alpha-helix/beta-sheet configuration of the TEA/ATTS DNA-binding domain of TEF-1. In the transient transfection assay, a positive cooperative effect of SRF and TEF-1 was observed when DNA-binding sites for both factors, serum response element and M-CAT respectively, were intact; mutation of either site abolished their synergistic effect. Similarly, an SRF mutant, SRFpm-1, defective in DNA binding failed to collaborate with TEF-1 for gene regulation, indicating that the synergistic trans-activation function of SRF and TEF-1 occurs via their binding to cognate DNA-binding sites. Our results demonstrate a novel association between SRF and TEF-1 for cardiac muscle gene regulation and disclose a general mechanism by which these two super families of factors are likely to control diversified biological functions.

A methylflavan with free radical scavenging properties from Pancratium littorale

The isolation of 7,4'-dihydroxy-8-methylflavan (1) from the dichloromethane extract of Pancratium littorale stem was guided by an assay for free radical scavenging activity towards the 2,2-diphenyl-1-picryl-hydrazyl radical (DPPH). The structure of 1 was established by spectrometric methods including UV, EI mass spectrometry, 1H and 13C-NMR. The free radical scavenging properties of 1 were quantified in solution using spectrophotometry.

Nitric oxide attenuates H(2)O(2)-induced endothelial barrier dysfunction: mechanisms of protection

Nitric oxide (.NO) attenuates hydrogen peroxide (H(2)O(2))-mediated injury in porcine pulmonary artery endothelial cells (PAECs) and modulates intracellular levels of cGMP and cAMP. We hypothesized that.NO attenuates H(2)O(2)-induced PAEC monolayer barrier dysfunction through cyclic nucleotide-dependent signaling mechanisms. To examine this hypothesis, cultured PAEC monolayers were treated with H(2)O(2), and barrier function was measured as transmonolayer albumin clearance. H(2)O(2) caused significant PAEC barrier dysfunction that was attenuated by intracellular as well as extracellular.NO generation.NO increased PAEC cGMP and cAMP levels, but treatment with inhibitors of soluble guanylate cyclase or protein kinase G did not abrogate.NO-mediated barrier protection. In contrast, H(2)O(2) decreased protein kinase A activity, and inhibiting protein kinase A abrogated the protective effect of.NO. H(2)O(2)-induced barrier dysfunction was not associated with decreased levels of cGMP or cAMP. 3-Isobutyl-1-methylxanthine and the cGMP analog 8-bromo-cGMP had little effect on H(2)O(2)-mediated endothelial barrier dysfunction, whereas 8-bromo-cAMP plus 3-isobutyl-1-methylxanthine was protective. These results indicate that.NO modulates vascular endothelial barrier function through cAMP-dependent signaling mechanisms.

Natural products research in latin america

The biodiversity found in Latin America is one of the richest in the world, yet its potential as a source of new pharmaceuticals has not been fully investigated. This paper will explore the present status of natural products research in 19 Latin American countries. Future research needs will be presented along with reports on the ethnobotanical and bioprospection projects under way in Latin America. The presentation will be based on data collected over the last five years and will be presented within the framework of the Fine Pharmaceutical Subprogram of the Iberoamerican Program of Science and Technology for Development (CYTED), a novel international cooperation program.

Biological screening of selected medicinal Panamanian plants by radioligand-binding techniques

Nineteen plants from the Republic of Panama were selected by their traditional uses in the treatment of hypertension, cardiovascular, mental and feeding disorders and 149 extracts were screened using radioligand-receptor-binding assays. The methanol:dicloromethane extracts of the bark and leaves of Anacardium occidentale L., the leaves of Begonia urophylla Hook., the roots of Bocconia frutescens L., the stems and leaves of Cecropia cf.obtusifolia Bertol., the branches of Clusia coclensis Standl., the bark of Cochlospermum vitifolium (Willd.)Spreng., the roots of Dimerocostus strobilaceus Kuntze, the bark of Guazuma ulmifolia Lam., the leaves of Persea americana Mill. and the branches of Witheringia solanaceae L'Her. inhibited the [3H]-AT II binding (angiotensin II AT1 receptor) more than 50%. Only extracts of the roots of Dimerocostus strobilaceus Kuntze and the stems of Psychotria elata (Sw.) Hammel were potent inhibitors of the [3H] NPY binding (neuropeptide Y Y1 receptor) more than 50% and the ethanolic extracts of the leaves of Cecropia cf. obtusifolia Bertol., the leaves of Hedyosmum bonplandianum H.B.K., the roots of Bocconia frutescens L., the stem of Cecropia cf. obtusifolia Bertol. and the branches of Psychotria elata (Sw.) Hammel showed high inhibition of the [3H] BQ-123 binding (endothelin-1 ET(A) receptor) in a preliminary screening. These results promote the further investigation of these plants using the same assays.

Iseluxine: a novel isoquinolinone alkaloid from Iseia luxurians

A novel isoquinolinone alkaloid, iseluxine (1), has been isolated from the epigeal parts of Iseia luxurians (MORIC.) O'DONELL (Convolvulaceae), a climber indigenous to the tropical Americas. Structural elucidation was achieved by HRMS, 1H NMR, 13C NMR, and HMBC spectroscopy. N- and/or O-methyl derivatives of 1 are already known from certain Magnoliidae families, e.g., the Fumariaceae, the Lauraceae, or the Papaveraceae. Iseluxine, the "missing link" in the biosynthesis of these methyl derivatives from dopamine, is the first isoquinolinone alkaloid characterized by a catechol substructure.

Antiplasmodial activity of isoflavones from Andira inermis

The stem bark and seeds of Andira inermis, Fabaceae, are employed as a purgative, vermifuge, and febrifuge. In particular, the powdered bark is claimed to be efficacious in intermittent fever. Bioassay-guided fractionation of lipophilic extracts from the stems and leaves yielded six isoflavones: biochanin A, calycosin, formononetin, genistein, pratensein, and prunetin. Calycosin (3', 7-dihydroxy-4'-methoxyisoflavone) and genistein (4',5, 7-trihydroxyisoflavone) have been shown to possess in vitro activity against the chloroquine-sensitive strain poW and the chloroquine-resistant clone Dd2 of Plasmodium falciparum.

Protein kinase-A dependent phosphorylation of transcription enhancer factor-1 represses its DNA-binding activity but enhances its gene activation ability

The cAMP-dependent signaling pathway has been implicated in cardiac cell growth/differentiation and muscle gene transcription. Previously, we have identified a cAMP-inducible E-box/M-CAT hybrid motif in the cardiac alpha-myosin heavy chain (alpha-MHC) gene promoter. The two factors, TEF-1 and Max, that bind to this motif are found to physically associate with each other and exert a positive cooperative effect for gene regulation. Here we show that TEF-1, but not Max, is a substrate for protein kinase-A (PK-A)-dependent phosphorylation. TEF-1 is phosphorylated by PK-A at residue serine-102. This post-translational modification of TEF-1 repressed its DNA-binding activity, but not its ability to interact with the Max protein. Replacement of serine-102 in TEF-1 by a neutral or a charged amino acid did not abolish its DNA-binding ability, suggesting that changing a charge at the 102 amino-acid position of TEF-1 was not sufficient to inhibit its DNA-binding activity. We also show that PK-A response of the alpha-MHC gene is stimulated by the presence of wild-type TEF-1 but not by mutant TEF-1 having serine-102 replaced by alanine, suggesting that phosphorylation at this residue accounts for the cAMP/PK-A response of the gene. Thus, these data demonstrate that TEF-1 is a direct target of cAMP/PK-A signaling in cardiac myocytes.

Dexamethasone induced cardiac hypertrophy in newborn rats is accompanied by changes in myosin heavy chain phenotype and gene transcription

Cardiac hypertrophy has been observed in newborn infants treated with dexamethasone (DEX). This study was undertaken to examine whether DEX-induced hypertrophy in newborn rats is associated with redistribution of cardiac myosin heavy chain (MHC) isoforms and, if so, the effects involve transcriptional regulation. Newborn rats were injected with either DEX (1 mg/kg/day; s.c.) or equivalent volume normal saline for 1, 3, 5, 7 or 9 days. Hypertrophy was quantified by heart dry/wet wt ratios, heart/body wt ratios, and total protein content of the myocardium. Changes in the expression of cardiac MHC mRNA were characterized by northern blot and slot blot analyses, using isoform specific probes for alpha- and beta-MHC genes. DEX effect on alpha-MHC gene transcription was analyzed by transiently transfecting various alpha-MHC promoter/CAT reporter constructs into primary cultures of cardiac myocytes derived from one day old rat pups. DEX administration into newborn rats produced significant cardiac hypertrophy ranging from 23% at day 1 to 59% at 9 days. The hypertrophy was accompanied by immediate increase (83%) in steady state level of the alpha-MHC mRNA within one day and a maximum increase (148%) at 7 days of treatment. The steady state level of beta-MHC mRNA declined by 25% at day 1 and a maximum decrease of 54% at day 7 of DEX treatment. The changes in MHC mRNA were also reflected in their protein levels as determined by V1 and V3 isozyme analysis. DEX treatment of primary cultures of cardiomyocytes following transfection with alpha-MHC promoter/CAT reporter constructs resulted in increased CAT expression in a dose dependent manner. The minimum alpha-MHC gene sequences responding to DEX treatment were located between the -200 to -74-bp region of the gene, resulting in 2-fold and 6-fold activation of CAT reporter after 0.05 and 0.1 mM doses of DEX, respectively. Our data indicate that DEX induced cardiac hypertrophy in newborn rats is accompanied by increased expression of alpha-MHC and decreased expression of beta-MHC. The alpha-MHC effects are mediated in part through transcriptional mechanisms.

Triterpene saponins from Randia formosa

Seven new triterpenoid saponins, randiasaponins I (1), II (2), III (3), IV (4), V (5), VI (6) and VII (7) as well as two known ones, ilexoside XXVII (8) and ilexoside XXXVII (9), were isolated from the methanolic extract of the leaves of Randia formosa. The structures of the new saponins were established as 3-O-alpha-L-arabinopyranosyl-3 beta,19 alpha,23-trihydroxyursa-12,20(30)-dien-28-oic acid 28-beta-D-glucopyranosyl ester (1), 3-O-beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranosyl rotundic acid (2), 3-O-beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranosyl pomolic acid 28-beta-D-glucopyranosyl ester (3), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl pomolic acid 28-beta-D-glucopyranosyl ester (4), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl siaresinolic acid 28-beta-D-glucopyranosyl ester (5), 3-O-alpha-L-arabinopyranosyl ilexosapogenin A 28-beta-D-glucopyranosyl ester (6), and 3-O-beta-D-glucopyranosyl ilexosapogenin A 28-beta-D-glucopyranosyl ester (7), based on spectral and chemical evidence. Besides the saponins, two common flavonoids kaempferol 3-O-rutinoside and rutin were also isolated.

Sipandinolide: a butenolide including a novel type of carbon skeleton from Siparuna andina

From a lipophilic extract of leaves of Siparuna andina (Monimiaceae), which exhibited antiplasmodial activity in vitro, two new compounds have been isolated: sipandinolide (1), a compound with a novel type of carbon skeleton and (-)-cis-3-acetoxy-4',5,7-trihydroxyflavanone (2). Their structures were established by spectroscopic methods; 2 showed moderate antiplasmodial activity whereas 1 was inactive.

Antifungal and larvicidal cordiaquinones from the roots of Cordia curassavica

In addition to the known cordiaquinones A and B, two novel meroterpenoid naphthoquinones, named cordiaquinones J and K, have been isolated from the roots of Cordia curassavica. Their structures were elucidated by spectrometric methods including EI, D/CI mass spectrometry, 1H, 13C and 2D-NMR experiments. The four naphthoquinones demonstrated antifungal activities against Cladosporium cucumerinum, Candida albicans and toxic properties against larvae of the yellow fever-transmitting mosquito Aedes aegypti.

Antifungal and larvicidal compounds from the root bark of Cordia alliodora

Two new natural products, a phenylpropanoid derivative characterized as 1-(3'-methoxypropanoyl)-2,4,5-trimethoxybenzene (1) and a prenylated hydroquinone, 2-(2Z)-(3-hydroxy-3,7-dimethylocta-2, 6-dienyl)-1,4-benzenediol (2), have been isolated from the root bark of Cordia alliodora. Both compounds exhibited antifungal properties against the phytopathogenic mold Cladosporium cucumerinum. The phenylpropanoid derivative (1), whose structure is closely related to beta-asarone, also demonstrated a marked activity against larvae of the yellow-fever-transmitting mosquito Aedes aegypti.

New natural sesquiterpenes as modulators of daunomycin resistance in a multidrug-resistant Leishmania tropica line

The effects produced by nine dihydro-beta-agarofuran sesquiterpenes isolated from Crossopetalum tonduzii (1-8) and Maytenus macrocarpa (9) (Celastraceae) on the reversion of the resistant phenotype on a multidrug-resistant Leishmania line and their binding to recombinant C-terminal nucleotide-binding domain of Leishmania P-glycoprotein-like transporter were studied. The structures of the new compounds (1-5) were elucidated by spectroscopic methods, including (1)H-(13)C heteronuclear correlation (HMQC), long-range correlation spectra with inversal detection (HMBC), ROESY experiments, and chemical correlations. The absolute configuration of one of them (1) was determined by CD studies. The structure-activity relationship is discussed.

In vitro antiplasmodial activity of Central American medicinal plants

The in vitro antiplasmodial activities of 14 plant species traditionally used in Central America for the treatment of malaria or fever were evaluated. Lipophilic extracts of Piper hispidum, Siparuna andina, S. pauciflora, S. tonduziana, and Xylopia cf. frutescens, proved to be active against both a chloroquine-sensitive and a resistant strain of Plasmodium falciparum. IC50 values ranged between 3.0 microg/ml and 21.9 microg/ml; however, moderate cytotoxicity of active extracts was observed. Bioactivity-guided fractionation of Piper hispidum yielded 2',4, 6'-trihydroxy-4'-methoxydihydrochalcone (asebogenin) as an active compound.

1',2',3',4'-tetradehydrotubulosine, a cytotoxic alkaloid from Pogonopus speciosus

Bioassay-guided phytochemical investigation of the stems of Pogonopus speciosus, using human oral epidermoid carcinoma (KB) cells as a monitor, led to the isolation of a novel alkaloid, 1',2', 3',4'-tetradehydrotubulosine (1), along with tubulosine (2) and psychotrine (3) as bioactive constituents. The structure of the novel compound was elucidated through 1D- and 2D-NMR spectroscopic methods. Alkaloids 1 and 3 showed weak cytotoxic activity against a panel of human cancer cell lines, with the potency of these compounds being markedly less than that of tubulosine (2).

Manganese superoxide dismutase in rat liver peroxisomes: biochemical and immunochemical evidence

By using highly purified peroxisomes from rat liver, we have shown that peroxisomes contain manganese superoxide dismutase (MnSOD) activity and a 23 kDa protein immunoreactive with antibodies against purified mitochondrial MnSOD. Immunocytochemical studies have also revealed immunoreaction (immunogold) with MnSOD antibodies in mitochondria and peroxisomes. Studies of the intraperoxisomal localization of MnSOD have shown that in peroxisomes MnSOD is a component of the peroxisomal limiting membranes and dense core. Furthermore, the MnSOD level in peroxisomes was modulated by oxidative stress conditions such as ischemia-reperfusion or the treatment with ciprofibrate, a peroxisomal proliferator. These findings suggest that MnSOD in peroxisomes may play an important role in the dismutation of superoxide generated on the peroxisomal membrane for keeping the delicate balance of the redox state.

A search for anti-viral properties in Panamanian medicinal plants. The effects on HIV and its essential enzymes

Aqueous and methanolic extracts of 39 Panamanian medicinal plants were tested for anti-human immunodeficiency virus (HIV) effects. The extracts were tested for the inhibition of HIV-induced cytopathic effects in cultured cells, HIV-reverse transcriptase (RT) and HIV-protease (PR) enzymes. The water extract of the branches of Jatropha curcas (Euphorbiaceae) inhibited strongly the HIV-induced cytopathic effects with low cytotoxicity. On the other hand, the water extracts of the whole plant of Chamaesyce hyssopifolia (Euphorbiaceae), the leaves of Cordia spinescens (Boraginaceae) and the aerial parts of Hyptis lantanifolia (Labiatae), and the methanol extract of the aerial parts of Tetrapteris macrocarpa (Malpighiaceae) were potent inhibitors of HIV-RT (IC50: 6-8 microg/ml). Seven out of 39 plants were found to be moderate inhibitors of HIV-PR (IC50: 43-100 microg/ml). Furthermore, we report on the respective inhibitory substances of J. curcas, C. hyssopifolia and C. spinescens, and their possible mechanism of action.

Tissue-restricted expression of the cardiac alpha-myosin heavy chain gene is controlled by a downstream repressor element containing a palindrome of two ets-binding sites

The expression of the alpha-myosin heavy chain (MHC) gene is restricted primarily to cardiac myocytes. To date, several positive regulatory elements and their binding factors involved in alpha-MHC gene regulation have been identified; however, the mechanism restricting the expression of this gene to cardiac myocytes has yet to be elucidated. In this study, we have identified by using sequential deletion mutants of the rat cardiac alpha-MHC gene a 30-bp purine-rich negative regulatory (PNR) element located in the first intronic region that appeared to be essential for the tissue-specific expression of the alpha-MHC gene. Removal of this element alone elevated (20- to 30-fold) the expression of the alpha-MHC gene in cardiac myocyte cultures and in heart muscle directly injected with plasmid DNA. Surprisingly, this deletion also allowed a significant expression of the alpha-MHC gene in HeLa and other nonmuscle cells, where it is normally inactive. The PNR element required upstream sequences of the alpha-MHC gene for negative gene regulation. By DNase I footprint analysis of the PNR element, a palindrome of two high-affinity Ets-binding sites (CTTCCCTGGAAG) was identified. Furthermore, by analyses of site-specific base-pair mutation, mobility gel shift competition, and UV cross-linking, two different Ets-like proteins from cardiac and HeLa cell nuclear extracts were found to bind to the PNR motif. Moreover, the activity of the PNR-binding factor was found to be increased two- to threefold in adult rat hearts subjected to pressure overload hypertrophy, where the alpha-MHC gene is usually suppressed. These data demonstrate that the PNR element plays a dual role, both downregulating the expression of the alpha-MHC gene in cardiac myocytes and silencing the muscle gene activity in nonmuscle cells. Similar palindromic Ets-binding motifs are found conserved in the alpha-MHC genes from different species and in other cardiac myocyte-restricted genes. These results are the first to reveal a role of the Ets class of proteins in controlling the tissue-specific expression of a cardiac muscle gene.