bluuebunny/crossref_metadata_2025_split huggingface dataset:
Replacement of Tyrosine-197 and the Corresponding Tyrosine-195 to Isoleucine in Cephalosporium acremonium and Streptomyces clavuligerus Isopenicillin N Synthase
Authors: Loke Paxton , Sim Tiow-Suan 
Published: February 2015

Abstract
Isopenicillin N synthase (IPNS) is one of the key enzymes in the penicillin and cephalosporin biosynthetic pathway which catalyses the conversion of δ-(ʟ-α-aminoadipyl)-ʟ-cysteinyl-ᴅ-valine to isopenicillin N. The IPNS from Penicillium chrysogenum 23X-80-269-37-2, a high penicillin V-producer, was found to possess an isoleucine residue instead of tyrosine at position 195. An attempt to increase the specific activity of IPNS from Cephalosporium acremonium and Streptomyces clavuligerus was undertaken by altering the corresponding tyrosine residue to an isoleucine at the corresponding location. Unfortunately, no apparent increase in specific activity was encountered when the purified mutant enzymes were analysed and thus, this amino acid difference is likely not responsible for high specific activity in IPNS.
An Ecto-ATPase Activity Present in Leishmania tropica Stimulated by Dextran Sulfate
Authors: Peres-Sampaio Carlos Eduardo , Palumbo Simone Thorp , Meyer-Fernandes José Roberto 
Published: February 2015

Abstract
In this study we report the effects of sulfated polysaccharides on the ecto-ATPase activity of intact cells of Leishmania tropica. Increasing concentrations of dextran sulfate stimulated progressively the ecto-ATPase activity, but did not modify other ecto-enzymes present on the surface of this parasite, such as 5′ nucleotidase, 3′nucleotidase and a membrane-bound acid phosphatase activity. This stimulation was not observed when other sulfated polysaccharides such as chondroitin sulfates and heparin were tested. It depends on size and charge of the dextran sulfated molecule. When the cells were incubated in the presence of dextran sulfate Mr 8,000; 40,000 and 500,000 the stimulation of the ecto-ATPase activity was 11%; 23%; and 63%, respectively, and the stimulation was not observed when desulfated dextran (Mr 40,000) was used. The effects of dextran sulfate also depend on pH of the medium. At pH 7.5, the stimulation was over 60%, whereas at pH 8.5 only 25%. The effects of dextran sulfate 500,000 on the ecto-ATPase activity was totally abolished by spermidine and partially by putrescine, two polyamines synthesized and released by Leishmania.
Negligible Ability of Oxygen and Peroxide Ion Activation by Al(III) Ion Is Essential for Al(III)-Induced Neurodegeneration
Authors: Nishida Yuzo 
Published: February 2015

Abstract
The electron densities of the atoms in Fe(II)-or Al(III)-tyrosine hydroxylase (THO) containing oxygen and pterin were calculated by the DFT (Density-functional theory) method. The results obtained are consistent with our previous proposal that oxygen activation in THO proceeds through the formation of an intermediate derived from Fe(II), oxygen, and pterin. Electron donation from substrate to the oxygen molecule is important to cleave the O-O bond, and to give the hydroxylated product. Based on these results, it was concluded that hydroxylation of the aromatic ring does not proceed in the Al(III)-containing THO, and a relationship exists between Al(III) ion and neurodegeneration.
Surface Charge and the Association of Liposomes with Colon Carcinoma Cells
Authors: Baczynska Dagmara , Widerak Katarzyna , Ugorski Maciej , Langner Marek 
Published: February 2015

Abstract
Interaction between the plasma membrane and aggregate lipid surface determines how efficiently the encapsulated drug will be delivered into the cell. Electrostatic interactions are one of the main forces affecting liposome and aggregate association with the charged cell surface. In this study, the effect of surface charge on the association of liposomes with human colon CX-1.1 cancer cells was studied. When phosphatidylserine was incorporated into a lipid bilayer, the amount of liposomes associated with cells tended to increase along with the amount of negatively charged lipid present in the liposomal lipid bilayer. When the cationic lipid dioleoyl-1,2-diacyl-3-trimethylammonium-propane (DOTAP) was included into the liposome formula, their uptake by the cells was also increased. Maximum binding occurred when the amount of positively charged lipids in liposomes was about 10 mol% of lipids.
The Pyoverdin of Pseudomonas fluorescens G173, a Novel Structural Type Accompanied by Unexpected Natural Derivatives of the Corresponding Ferribactin
Authors: Fernández Diana Uría , Fuchs Regine , Schäfer Mathias , Budzikiewicz Herbert , Meyer Jean-Marie 
Published: February 2015

The siderophores produced by Pseudomonas fluorescens G173 are unusual in several respects. So far all pyoverdins with a C-terminal cyclopeptidic substructure have in common that the ε-amino group of an in-chain Lys is bound amidically to the carboxyl group of a C-terminal Ser or Thr and that N5-formyl-N5-hydroxy Orn (FoOHOrn) is the next amino acid after Lys. FoOHOrn may (cyclotetrapeptidic structures) be or may not (cyclotripeptidic structures) be followed by a further amino acid. In the pyoverdin described here Orn instead of Lys is the amino acid forming the cycle, FoOHOrn is replaced by AcOHOrn which does not follow the branching Orn but is the penultimate amino acid and finally the last amino acid is Asp. The producing strain which had been classified as Pseudomonas fluorescens may well be a new species.
Pyoverdins are frequently accompanied by ferribactins which are considered to be their biogenetic precursors. They always have the same amino acid chain as the co-occurring pyoverdins but the pyoverdin chromophore is replaced by a condensation product of ʟ-Dab and ᴅ-Tyr with the amino group of Tyr bound to the γ-carboxyl group of Glu. A ferribactin having these structural characteristics is produced by the investigated strain, but it is accompanied by derivatives where the α-amino group of Glu is partially or completely transformed into a hydroxamic acid by substitution with a hydroxyl and/or acetyl group
Effect of a Fungal Cu/Zn Superoxide Dismutase on the Cell-Mediated Immune Response in Graffi Tumor Bearing Hamsters
Authors: Toshkova Reneta , Ivanova Emilia , Angelova Maria , Dolashka Pavlina , Voelter Wolfgang 
Published: February 2015

The antibody-dependent cell cytotoxicity (ADCC) of spleen lymphocytes, isolated fromhamsters with progressing myeloid Graffi tumor, was studied. The effect of the application of Cu/Zn superoxide dismutase, isolated from the fungal strain Humicola lutea (HL SOD), before and during tumor transplantation on the lymphocyte ADCC was examined. Myeloid Graffi tumor cells as target cells were used. Antibodies from a rabbit hyper-immune anti-tumor Graffi cells serum, or from tumor-bearing hamsters serum were used in the test. The leukocyte adherence inhibition (LAI) in the presence of tumor antigenwas examined also during tumor progression.
ADCC of the spleen lymphocytes, determined by both, rabbit and hamster anti-tumor antibodies, decreased during tumor progression. The optimum treatment of the animals by HL SOD induced a 20-30% increase of lymphocyte cytotoxicity againstmyeloid Graffi tumor cells. Cytotoxicity in presence of tumor bearing hamsters serum was twofold lower as compared to that one determined in the presence of rabbit hyper-immune anti-myeloid Graffi tumor cells serum.
Leukocyte adherence inhibition (LAI) index in the presence of tumor antigen increased during tumor development in the groups of treated and untreated animals. The LAI indices of HL SOD-treated tumor-bearing hamsters were lower than that of untreated animals with tumors, what can be explained by a higher adherence ability of leukocytes induced by HL SOD treatment (in formula for calculation of LAI index the adherence value is in the denominator).
The results show the beneficial effect of HL SOD on the cell- mediated immune response of myeloid Graffi tumor bearing hamsters, what is probably due to the participation of the enzyme in the host’s oxidant-antioxidant balance
Comparative Analysis of the Composition of Flower Volatiles from Lamium L. Species and Lamiastrum galeobdolon Heist. ex Fabr.
Authors: Alipieva Kalina , Evstatieva Ljubka , Handjieva Nedjalka , Popova Simeon 
Published: February 2015

Abstract
The volatiles of fresh flowers from nine natural populations of four Lamium species and Lamiastrum galeobdolon were analyzed by GC/MS. 49 compounds, 43 of them new for Lamium and Lamiastrum, were identified. The studied samples showed similarity of the volatile profiles and dependence of the oil-composition on the collection site. Significant amounts of squalene were found in all samples. The presence of homological series of straight chain alkanes from C12 to C31 was shown. Phenethyl alcohol was found only in L. maculatum f. alba.
Volatile Composition of Jasonia glutinosa D. C.
Authors: Romero María Angeles González , Castillo Lucinda Villaescusa , Lanza Ana María Díaz , Bricio José María Arribas , Monzón Cristina A. Soria , Perucha Jesús Sanz 
Published: February 2015

Abstract
Using GC-MS the volatile composition of Jasonia glutinosa D. C., was studied by comparing two different methods for the isolation of a volatile fraction: distillation from the fresh plant in order to obtain the essential oil, and direct thermal desorption (DTD). Compared with essential oil extraction the main advantages of the DTD technique are the smaller sample amount required, and the increased range of volatile compounds which can be subsequently analysed by GC-MS.
The Anticancer Drug Cytarabine Does not Interact with the Human Erythrocyte Membrane
Authors: Suwalsky Mario , Hernández Pedro L. , Villena Fernando , Sotomayor Carlos P. 
Published: February 2015

Abstract
Cytarabine, an analog of deoxycytidine, is an important agent in the treatment of ovarian carcinoma, acute myeloid and lymphoblastic leukemia. Its mechanism of action has been attributed to an interference with DNA replication. The plasma membrane has received increasing attention as a possible target of antitumor drugs, where the drugs may act as growth factor antagonists and receptor blockers, interfere with mitogenic signal transduction or exert direct cytotoxic effects. Furthermore, it has been reported that drugs that exert their antiproliferative effect by interacting with DNA generally cause structural and functional membrane alterations which may be essential for growth inhibition by these agents. This paper describes the studies undertaken to determine the structural effects induced by cytarabine to cell membranes. The results showed that cytarabine, at a concentration about one thousand times higher than that found in plasma when it is therapeutically administered, did not induce significant structural perturbation in any of these systems. Therefore, it can be unambiguously concluded that this widely used anticancer drug does not interact at all with erythrocyte membranes.
Three Highly Oxygenated Caryophyllene Sesquiterpenes from Pestalotiopsis sp., a Fungus Isolated from Bark of Pinus taeda
Authors: Magnan Rodrigo F. , Rodrigues-Fo Edson , Daolio Cristina , Ferreira A. Gilberto , Souza Antonia Q. L. de 
Published: February 2015

Abstract
A Pestalotiopis sp. was isolated from the trunk bark of Pinus taeda. The fungus was cultivated in liquid medium and produced three highly oxygenated caryophyllene sequiterpene derivatives, named pestalotiopsolide A, taedolidol and 6-epitaedolidol, respectively. The sesquiterpenes were isolated by silica gel based chromatographic procedures and their structures were elucidated by NMR spectroscopic data.
Evaluation of Sage Phenolics for Their Antileishmanial Activity and Modulatory Effects on Interleukin-6, Interferon and Tumour Necrosis Factor-α-Release in RAW 264.7 Cells
Authors: Radtke Oliver A. , Foo Lai Yeap , Lu Yinrong , Kiderlen Albrecht F. , Kolodziej Herbert 
Published: February 2015

Abstract
A series of sage phenolics was tested for activity against a panel of Leishmania parasites and for immunomodulatory effects on macrophage functions including release of tumour necrosis factor (TNF), interleukin-6 (IL-6), and interferon (IFN)-like activities. For this, functional bioassays were employed including an in vitro model for leishmaniasis in which macrophage- like RAW 264.7 cells were infected with Leishmania parasites, an extracellular Leishmania growth-inhibition assay, a fibroblast-lysis assay for TNF-activity, a cell proliferation assay using IL-6 sensitive murine B9 hybridoma cells, and a virus protection assay for IFN-like activity. Whereas none of the test samples exhibited marked activities against extracellular Leishmania promastigotes (IC50 > 700 to > 2800 nм; > 500 μg/ml), caffeic acid, salvianolic acids K and L as well as the methyl ester of salvianolic acid I showed pronounced antileishmanial activities against intracellular amastigote stages within RAW cells (IC50 3-23 nм vs. 10-11 nм for the reference Pentostam®). Noteworthy, the phenolic samples showed no cytotoxicity against the host cells (IC50 > 600 to > 2200 nм; > 400 μg/ml). Tested sage phenolics activated Leishmania-infected RAW 264.7 for release of TNF ranging 22-117 U/ml and IL-6 ranging 3-42 U/ml. In contrast, their TNF- or IL-6-inducing potential in experiments with non-infected host cells was negligible. Furthermore, caffeic acid and salvianolic acid K induced a modest release of IFN-like activity (5-9 and 2-4 U/ml, respectively) as reflected by inhibition of the cytopathic effect of encephalomyocarditis virus on L929 cells. The results support the emerging picture that plant polyphenols may be credited for the profound healthbeneficial properties of various herbal medicines and agricultural products.
Starvation-Induced Impairment of Metabolism in a Freshwater Catfish
Authors: Tripathi Ghanshyam , Verma Priyanka 
Published: February 2015

Abstract
Starvation induced changes in citrate synthase (CS), glucose-6-phosphate dehydrogenase (G6-PDH), lactate dehydrogenase (LDH), DNA, RNA, RNA/DNA ratio and protein were studied in the freshwater catfish Clarias batrachus. Starvation gradually decreased the activity of CS, G6-PDH and LDH in brain, liver and skeletal muscle of the freshwater catfish. The maximum reduction in these enzyme activities upto 35-45% was observed after 35 days of fasting. This shows substantial decline in aerobic and biosynthetic capacity during starvation period. DNA, RNA, RNA/DNA ratio and protein contents were also reduced from 40-67% which reflects reduction in an overall capacity of the protein synthesis. Starvation - induced macromolecular changes indicate impairment of metabolism in fish.
Iridoid Glucosides from Veronica pectinata var. glandulosa
Authors: Harput U. Sebnem , Nagatsu Akito , Ogihara Yukio , Saracoglu Iclal 
Published: February 2015

Abstract
A new highly oxygenated iridoid glucoside, urphoside B (1) was isolated from the Veronica pectinata var. glandulosa together with seven known iridoid glucosides, aucubin, catalpol, veronicoside, catalposide, verproside, amphicoside and 6-O-veratroyl catalpol. The planar as well as the stereo structures of the isolated compounds were determined by means of extensive 1D- and 2D-NMR spectroscopy and confirmed by HR-Mass.
Cytotoxic Naphthoquinones from Roots of Lippia microphylla
Authors: Santos Hélcio S. , Costa Sônia M. O. , Pessoa Otília D. L. , Moraes Manoel O. , Pessoa Claudia , Fortier Sergio , Silveira Edilberto R. , Lemos Telma L. G. 
Published: February 2015

Abstract
A new prenylated naphthoquinone dimer named microphyllaquinone (1), a mixture of 6-methoxy- and 7-methoxy-naphtho[2,3-b]-furan-4,9-quinones (2a/2b) and tecomaquinone I (3), were isolated from roots of Lippia microphylla. The structures were elucidated by spectroscopic methods, including detailed 1D and 2D (COSY, NOESY, HMQC, HMBC) NMR data. Unpublished 13C NMR data of 2a and 2b are reported. The in vitro cytotoxic activity of the isolated compounds was tested against five types of tumor cells.
Dacrymenone and VM 3298-2 - New Antibiotics with Antibacterial and Antifungal Activity
Authors: Mierau Viktor , Anke Timm , Sterner Olov 
Published: February 2015

Abstract
Two new antibiotic metabolites, dacrymenone (1) and VM 3298-2 (2), were isolated from fermentations of a Dacrymyces sp., and their structures were determined by spectroscopic techniques. Dacrymenone (1) is a new eremophilane sesquiterpenoid while VM 3298-2 (2) is a bis-enol ether between methyl pyruvate and 4,6-dihydroxycyclohexan-1,3-dione. Dacrymenone (1) shows weak antibacterial and antifungal activity while VM 3298-2 (2) exhibits cytotoxic and antifungal activities.
ʟ-5-Hydroxytryptophan: Antioxidant and Anti-Apoptotic Principle of the Intertidal Sponge Hymeniacidon heliophila
Authors: Lysek Nicola , Kinscherf Ralf , Claus Ralf , Lindel Thomas 
Published: February 2015

Abstract
The intertidal sponge Hymeniacidon heliophila which survives under intense sunlight contains the antioxidant amino acid l-5-hydroxytryptophan (ʟ-5-HTP) as major constituent. The content of ʟ-5-HTP was determined as (0.45 ± 0.23)% of the dry weight by quantitative NMR-spectroscopical analysis with an internal standard. Other known antioxidants such as flavonoids, carotenoids or tocopherol derivatives were absent. Both the oxidation potential and the concentration of ʟ-5-HTP in H. heliophila correspond to the values observed for flavonoids being major antioxidants in plants. It was shown that ʟ-5-HTP suppresses UVinduced apoptosis in human monocytes at the same concentrations as it occurs in the sponge tissue.
Hydrogen Peroxide from the Oxidative Burst is Not Involved in the Induction of Taxol Biosynthesis in Taxus chinensis Cells
Authors: Lan Wen Zhi , Qin Wen Min , Yu Long Jiang , Yang Xi 
Published: February 2015

Abstract
In cell suspension cultures of Taxus chinensis, 40 mg/l fungal elicitor from Aspergillus niger and 20 μm HgCl2 elicited 5.7 and 3.6 mg/l taxol, which was a 9-fold and 5- fold increase vs. compared with the control, respectively. The fungal elicitor induced hydrogen peroxide (H2O2) accumulation but HgCl2 did not, indicating that H2O2 was not necessary for enhancement of taxol induced by elicitor. Compared with the treatment with fungal elicitor alone, exogenous catalase, ascorbic acid, diphenylene iodonium and superoxide dismutase induced a 0.45, 0.4, 0.7 and 1.4-fold H2O2, but elicited taxol production, which was 0.98, 1.2, 1.1 and 0.9-fold, respectively, vs. non-treated cells. Elicitor-induced taxol production was not accorded with the amount of H2O2 production.
Pyrone Glycosides from Acosmium panamense (Benth.) Yacovlev
Authors: Wiedenfeld Helmut , Andrade-Cetto Adolfo 
Published: February 2015

Abstract
Besides caffeic acid three pyrones have been isolated from aquous bark extracts from Acosmium panamense and their structures were determined using spectroscopical methods. Besides the already described desmethylyangonine its O4′-mono as well as the di(1-6)glucoside are found the first time.
Two New 24-Isopropenyl-lanostanoids from Tillandsia brachycaulos
Authors: Cantillo-Ciau Zulema , Mena-Rejón Gonzalo J. , Quintero-Mármol Esther , Jiménez-Díaz Antonio , Quijano Leovigildo 
Published: February 2015

Abstract
The leaves of Tillandsia brachycaulos afforded two novel tetracyclic triterpenoids identified as (24S)-24-isopropenyl-29-nor-5α-lanosta-7-en-3β-ol (1) and (24S)-24-isopropenyl-29-nor- 5α-lanosta-7-en-3-one (2), in addition to the known isopimaric acid (3) and chlorogenic acid (4). Their structures were elucidated on the basis of spectral analysis, including homo- and heteronuclear correlation NMR experiments (COSY, ROESY, HMQC and HMBC) and by comparison with data in the literature. The antimicrobial and antifungal activities were studied. The compounds did not show significant activity.
Antiproliferative Effects of Several Compounds Isolated from Amburana cearensis A. C. Smith
Authors: Costa-Lotufo Letícia V. , Jimenez Paula C. , Wilke Diego V. , Leal Luzia Kalyne A. M. , Cunha Geanne M. A. , Silveira Edilberto R. , Canuto Kirley M. , Viana Glauce S. B. , Moraes Maria Elisabete A. , Moraes Manoel Odorico de , Pessoa Cláudia 
Published: February 2015

Abstract
Amburana cearensis a common tree found in Northeastern Brazil is widely used in folk medicine. The present work evaluated the cytotoxicity of kaempferol, isokaempferide, amburoside A and protocatechuic acid isolated from the ethanol extract of the trunk bark of A. cearensis. The compounds were tested for their cytotoxicity on the sea urchin egg development, hemolysis assay and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay using tumor cell lines. Isokaempferide and kaempferol, but not amburoside A and protocatechuic acid, inhibited the sea urchin egg development as well as tumor cell lines, but in this assay isokaempferide was more potent than kaempferol. Protocatechuic acid was the only compound able to induce hemolysis of mouse erythrocytes, suggesting that the cytotoxicity of kaempferol and isokaempeferide was not related to membrane damage.
DNA Breaks Induction by Mimosine
Authors: Mladenov Emil , Anachkova Boyka 
Published: February 2015

Abstract
Mouse erythroleukemic F4 N cells were treated with mimosine, etoposide, Fe(II)-EDTA, and Cu(II) in the presence of ascorbate. DNA was isolated and subjected to agarose gel electrophoresis and the size and distribution of the DNA fragments produced by the agents were compared. With increasing concentration of Cu(II) the production of DNA fragments was increased without decrease of the average length of the fragments, and their sizes were similar to those produced by etoposide as expected for cleavage of DNA at the nuclear matrix attachments sites. In contrast, mimosine and Fe(II) produced fragments of random size and with the progression of the reaction the average length of the fragments decreased. These results indicate that mimosine cuts DNA in a random fashion, regardless of its higher order chromatin organization. A conclusion is drawn that the DNA fragments obtained after mimosine treatment are a result of mimosine-assisted, Fe(II) dependent Fenton-like reactions randomly cutting chromosomal DNA.
Secondary Metabolite Content in Fabiana imbricata Plants and in vitro Cultures
Authors: Schmeda-Hirschmann Guillermo , Jordan Miguel , Gerth André , Hormazabal Emilio , Tapia Alejandro A. , Wilken Dirk 
Published: February 2015

A rapid in vitro propagation system leading to the formation of shoots, calli, roots, cell suspensions and plantlets was developed for the Andean medicinal plant Fabiana imbricata (Solanaceae). Massive propagation of shoots and roots was achieved by the temporary immersion system (TIS), morphogenesis and maintenance of cell suspensions by standard in vitro culture techniques. Oleanolic acid (OA), rutin, chlorogenic acid (CA) and scopoletin content in aerial parts of wild growing Fabiana imbricata plants as well as in plantlets regenerated in vitro, callus cultures, cell suspensions and biomass, obtained by the TIS system was assessed by HPLC.
On a dry weight basis, the OA content in the aerial parts of the plant ranged between 2.26 and 3.47% while in vitro plantlets, callus and root cultures presented values ranging from not detected up to 0.14%. The rutin content of the samples presented a similar trend with maxima between 0.99 and 3.35% for the aerial parts of the plants to 0.02 to 0.20% for plantlets, 0.12% for cell suspensions and 0.28% for callus. Rutin was not detected in the roots grown by the TIS principle. The CA and scopoletin content in the aerial parts of F. imbricata ranged between 0.22-1.15 and < 0.01-0.55%, respectively. In the plantlets, the concentration of CA was 0.29 to 1.48% with scopoletin in the range 0.09 to 0.64% while in the callus sample, the CA and scopoletin content were 0.46 and 0.66%, respectively. A very different result was found in roots grown by TIS, where both OA and rutin were not detected and its main secondary metabolite, scopoletin was found between a range of 0.99 and 1.41% with CA between of 0.11 and 0.42%.