Search Results - (Author, Cooperation:I. Martins)

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  1. 1
    Staff View
    Publication Date:
    2018-01-18
    Publisher:
    Wiley-Blackwell
    Print ISSN:
    0012-9658
    Electronic ISSN:
    1939-9170
    Topics:
    Biology
    Published by:
    http://www.wiley.com/wiley-blackwell

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Staff View
    Publication Date:
    2011-12-17
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Adenosine Triphosphate/metabolism ; Animals ; Antineoplastic Agents/*pharmacology/therapeutic use ; Autophagy/drug effects/*physiology ; Calreticulin/pharmacology ; Cell Death/immunology ; Cell Line, Tumor ; Dendritic Cells/immunology ; Humans ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Mitoxantrone/pharmacology ; Neoplasms/drug therapy/*immunology
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    Staff View
    Publication Date:
    2012-09-29
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Animals ; Calreticulin/immunology ; Cell Line, Tumor ; Common Variable Immunodeficiency/genetics ; DNA, Neoplasm/analysis/genetics ; Endoplasmic Reticulum Stress/*immunology ; Eukaryotic Initiation Factor-2/metabolism ; Humans ; Immunocompetence ; *Immunologic Surveillance ; Mice ; Mice, Inbred BALB C ; Neoplasms/chemically induced/*genetics/*immunology ; Phosphorylation ; *Ploidies
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  4. 4
    Mortimer, B-C ; Martins, I. ; Zeng, BJ ; Redgrave, TG

    Oxford, UK : Blackwell Publishing Ltd
    Published 1997
    Staff View
    ISSN:
    1440-1681
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Medicine
    Notes:
    1. In vivo and in vitro gene-manipulated models were used to study the metabolism of chylomicron remnants. Transgenic mice expressing human apolipoprotein (Apo) A1 or E4, gene knockout mice deficient in ApoE or low density lipoprotein (LDL) receptors and antisense gene inhibition in HepG2 cells were used to evaluate the effect of gene manipulations on the metabolism of chylomicron remnants.2. Mice transgenic for human ApoE4 showed accelerated clearance of chylomicron-like emulsions when animals were fed a low-fat diet. When challenged by a high-fat diet, remnant clearance in ApoE4 transgenic mice was delayed, as in normal or non-transgenic controls. However, unlike normal non-transgenic controls, in ApoE4 transgenic mice high density lipoprotein (HDL)-choIesterol levels remained high after high-fat feeding, which probably protected the animals from the development of atherosclerosis.1 In contrast, clearance of chylomicron-like lipid emulsions was not affected by the over-expression of human ApoAI in transgenic mice.3. Gene knock-out mice deficient in ApoE or deficient in the LDL receptor were used to show that ApoE and LDL receptors are both essential for the normal, fast catabolism of chylomicron remnants by the liver.2 In the absence of the LDL receptor, an alternative ApoE-dependent pathway operates to clear chylomicrons from the plasma, with significantly delayed catabolism.4. Antisense gene inhibition techniques were used to suppress the expression of syndecan, a core protein of heparan sulfate proteoglycan, in HepG2 cells. Remnant uptake in cells transfected with the antisense oligodeoxynucleotide complementary to a 20 nucleotide sequence upstream of the initiation site of syndecan cDNA markedly reduced the uptake of chylomicron remnant.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1440-1681.1997.tb01820.x

    Articles: DFG German National Licenses
  5. 5
    Staff View
    ISSN:
    0005-2760
    Keywords:
    (Rat) ; Cholesteryl ester metabolism ; Lipid emulsion ; Lipolysis ; Phosphatidylcholine metabolism ; Triacylglycerol metabolism
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0005-2760(88)90016-1

    Articles: DFG German National Licenses
  6. 6
    Verma, R.S. ; Spencer-Martins, I. ; Van Uden, N.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0005-2736
    Keywords:
    (P. ohmeri) ; Cycloheximide ; Facilitated diffusion ; Glucose transport ; Glucose/proton symport
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0005-2736(87)90285-9

    Articles: DFG German National Licenses
  7. 7
    Spencer-Martins, I. ; Van Uden, N.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0005-2736
    Keywords:
    (Candida) ; Catabolite inactivation ; Glucose proton symport ; Multiple transport system
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0005-2736(85)90535-8

    Articles: DFG German National Licenses
  8. 8
    Spencer-Martins, I.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0960-8524
    Keywords:
    Sugar transport ; ethanol ; fermentation conditions ; lignocellulosic materials ; mixed sugars ; yeast
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/0960-8524(94)90220-8

    Articles: DFG German National Licenses
  9. 9
    Cason, David T. ; Spencer-Martins, I. ; Uden, N.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1986
    Staff View
    ISSN:
    1574-6968
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Biology
    Notes:
    Abstract Saccharomyces cerevisiae IGC4261, a brewing strain, transported fructose and sorbose but not glucose by a high-affinity, low-capacity proton symport. The symport was not subject to glucose repression and coexisted with the facilitated diffusion system for glucose, fructose, sorbose and other sugars. Transport by the symport was accumulative. The stoichiometry was one proton per molecule of fructose. Maltose acted as a non-competitive inhibitor.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1574-6968.1986.tb01715.x

    Articles: DFG German National Licenses
  10. 10
    Butinar, L. ; Santos, S. ; Spencer-Martins, I. ; Oren, A. ; Gunde-Cimerman, N.

    Oxford, UK : Blackwell Publishing Ltd
    Published 2005
    Staff View
    ISSN:
    1574-6968
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Biology
    Notes:
    Thus far it has been considered that hypersaline natural brines which are subjected to extreme solar heating, do not contain non-melanized yeast populations. Nevertheless we have isolated yeasts in eight different salterns worldwide, as well as from the Dead Sea, Enriquillo Lake (Dominican Republic) and the Great Salt Lake (Utah). Among the isolates obtained from hypersaline waters, Pichia guilliermondii, Debaryomyces hansenii, Yarrowia lipolytica and Candida parapsilosis are known contaminants of low water activity food, whereas Rhodosporidium sphaerocarpum, R. babjevae, Rhodotorula laryngis, Trichosporon mucoides, and a new species resembling C. glabrata were not known for their halotolerance and were identified for the first time in hypersaline habitats. Moreover, the ascomycetous yeast Metschnikowia bicuspidata, known to be a parasite of the brine shrimp, was isolated as a free-living form from the Great Salt Lake brine. In water rich in magnesium chloride (bitterns) from the La Trinitat salterns (Spain), two new species provisionally named C. atmosphaerica– like and P. philogaea– like were discovered.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/j.femsle.2005.01.043

    Articles: DFG German National Licenses
  11. 11
    Spencer-Martins, I. ; Uden, N.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1985
    Staff View
    ISSN:
    1574-6968
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Biology
    Notes:
    Abstract Under conditions of derepression the yeast Candida wickerhamii formed a high-affinity glucose proton symport. Glucose and glucose analogues induced inactivation of the glucose proton symport and its interconversion into a low-affinity facilitated diffusion system. The specific inactivation rate increased with the concentration of the inactivating sugar and did not obey saturation kinetics. This dependence was still pronounced at sugar concentrations far above saturation of the glucose transport systems. This suggested that the inactivation and interconversion mechanism was triggered by interaction of the inactivating sugar with receptor sites located on the cell surface.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1574-6968.1985.tb00805.x

    Articles: DFG German National Licenses
  12. 12
    Sano-Martins, I. S. ; Jared, C. ; Brunner, A.
    Springer
    Published 1994
    Staff View
    ISSN:
    1433-2981
    Keywords:
    ADP ; Snake ; Thrombocyte ; Ultrastructure ; Waglerophis merremii
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Notes:
    Abstract The ultrastructure of the resting thrombocytes of the snake Waglerophis merremii and the process of ADP aggregation are studied. These thrombocytes are nucleate, ellipsoidal, and contain a marginal band. Endoplasmic reticulum and ribosomes are few. An open canalicular system, Golgi complex, granules resembling the alpha-granules in human platelets, and structures similar to secondary lysosomes are also present. The activation response of W. merremii thrombocytes to ADP is examined and compared to the morphological alterations in human platelets. The thrombocytes, normally ellipitical in shape, become spheroid with cytoplasmic protrusions, and adhere to one another. The open canalicular system undergoes dilation and the granules cluster at the centre of the thrombocytes. The release reaction of these granules occurs after stimulation by ADP, similar to what happens in human platelets. This similarity may suggest a process of evolutional specialization since thrombocytes in the majority of non-mammal vertebrates are not aggregated by ADP.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00185178

    Articles: DFG German National Licenses
  13. 13
    Spencer-Martins, I. ; Uden, N.
    Springer
    Published 1986
    Staff View
    ISSN:
    1432-0614
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Process Engineering, Biotechnology, Nutrition Technology
    Notes:
    Summary Cellobiose-grown cells of Candida wickerhamii transported cellobiose as glucose by a glucose-proton symport after previous hydrolysis of the disaccharide by an exocellular β-glucosidase. Both the symport and the β-glucosidase were subject to glucose-induced repression and inactivation while glucose also acted as a competitive inhibitor of the enzyme (K i 0.3 mM). Under conditions of glucose repression glucose was transported by facilitated diffusion. Cellobiose acted as a competitive inhibitor of the latter (K i 75 mM) and is possibly a low-affinity substrate, while it inhibited non-competitively the glucoseproton symport (K i 80 mM). The affinity of cellobiose for the cell-bound β-glucosidase was much higher (K m 4.2 mM) than for the purified enzyme as reported by others (K m 67–225 mM). Ethanol reversibly inhibited the two glucose transport systems with exponential non-competitive kinetics. The minimum inhibitory concentrations were about 3% and 4% (w/v) for facilitated diffusion and proton symport while the respective exponential inhibition constants were 0.58 l mol-1 and 1.65 l mol-1. Ethanol affected the β-glucosidase in a complex way, a major effect was deviation from Michaelis-Menten kinetics for ethanol concentrations higher than 4% (w/v), the Hill coefficient increasing up to 1.8 at 6% (w/v) ethanol.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00253662

    Articles: DFG German National Licenses
  14. 14
    Spencer-Martins, I. ; Uden, N.
    Springer
    Published 1977
    Staff View
    ISSN:
    1432-0614
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Process Engineering, Biotechnology, Nutrition Technology
    Notes:
    Summary A survey was made of 81 starch-assimilating yeasts, representing 59 species and varieties, with respect to their capacity for the direct conversion of starch into SCP. The extent of starch conversion by the native amylases of the strains during exponential growth, expressed as yield on starch (final amount of dry biomass formed per unit mass of starch originally supplied), varied over a wide range (0.043–0.590) The highest yields were obtained with strains ofLipomyces starkeyi andL. kononenkoae which converted on the average respectively 84% and nearly 100% of the starch supplied. The rate of starch hydrolysis byL. kononenkoae did not limit its specific rate of growth and SCP production.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01390667

    Articles: DFG German National Licenses
  15. 15
    Hossack, J. A. ; Spencer-Martins, I.
    Springer
    Published 1978
    Staff View
    ISSN:
    1432-0614
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Process Engineering, Biotechnology, Nutrition Technology
    Notes:
    Summary The lipids of two strains of Lipomyces kononenkoae, grown in batch culture, were extracted and analysed. The major lipids present were phospholipids, free sterols, esterified sterols, and triacylglycerols. Phospholipid analysis indicated that phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol were the major ones. The fatty-acyl residues were C12-C18 and contained 67–74% unsaturated residues. Polyunsaturated residues accounted for 15% and 30% in L. kononenkoae CBS 2514 and L. kononenkoae CBS 5608, respectively. Analysis of the fatty-acyl residues of a low-density vesicle fraction obtained from sphaeroplasts of L. kononenkoae CBS 2514 was carried out and the results are discussed in relation to plasma membrane synthesis. The suitability of L. kononenkoae for production of single-cell protein is also discussed.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00504715

    Articles: DFG German National Licenses
  16. 16
    Staff View
    ISSN:
    1432-0614
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Process Engineering, Biotechnology, Nutrition Technology
    Notes:
    Abstract Anaerobic xylulose fermentation was compared in strains of Zygosaccharomyces and Saccharomyces cerevisiae, mutants and wild-type strains to identify host-strain background and genetic modifications beneficial to xylose fermentation. Overexpression of the gene (XKS1) for the pentose phosphate pathway (PPP) enzyme xylulokinase (XK) increased the ethanol yield by almost 85% and resulted in ethanol yields [0.61 C-mmol (C-mmol consumed xylulose)−1] that were close to the theoretical yield [0.67 C-mmol (C-mmol consumed xylulose)−1]. Likewise, deletion of gluconate 6-phosphate dehydrogenase (gnd1Δ) in the PPP and deletion of trehalose 6-phosphate synthase (tps1Δ) together with trehalose 6-phosphate phosphatase (tps2Δ) increased the ethanol yield by 30% and 20%, respectively. Strains deleted in the promoter of the phosphoglucose isomerase gene (PGI1) – resulting in reduced enzyme activities – increased the ethanol yield by 15%. Deletion of ribulose 5-phosphate (rpe1Δ) in the PPP abolished ethanol formation completely. Among non-transformed and parental strains S. cerevisiae ENY. WA-1A exhibited the highest ethanol yield, 0.47 C-mmol (C-mmol consumed xylulose)−1. Other non-transformed strains produced mainly arabinitol or xylitol from xylulose under anaerobic conditions. Contrary to previous reports S. cerevisiae T23D and CBS 8066 were not isogenic with respect to pentose metabolism. Whereas, CBS 8066 has been reported to have a high ethanol yield on xylulose, 0.46 C-mmol (C-mmol consumed xylulose)−1 (Yu et al. 1995), T23D only formed ethanol with a yield of 0.24 C-mmol (C-mmol consumed xylulose)−1. Strains producing arabinitol did not produce xylitol and vice versa. However, overexpression of XKS1 shifted polyol formation from xylitol to arabinitol.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s002530051629

    Articles: DFG German National Licenses
  17. 17
    Spencer-Martins, I. ; Uden, N.
    Springer
    Published 1979
    Staff View
    ISSN:
    1432-0614
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Process Engineering, Biotechnology, Nutrition Technology
    Notes:
    Summary A strain of the yeast Lipomyces kononenkoae which converted starch into SCP with a high yield, produced three extracellular amylases which were purified from the culture fluid by Ficoll concentration, dialysis, isopropanol precipitation and DE-cellulose chromatography: an α-amylase, a glucoamylase and a debranching transferase. The latter transferred α-1,6-glucosyl units from panose to glucose forming maltose and appeared to have some debranching activity on amylopectin. The α-amylase had the following properties: MW 38000 daltons; no effect of added calcium ions on activity; optimum temperature and pH for activity around 40°C and pH 5.5; ΔH
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00508096

    Articles: DFG German National Licenses
  18. 18
    Staff View
    ISSN:
    1432-0428
    Keywords:
    Key words Chylomicrons, chylomicron remnants, intestine, diabetes mellitus, apolipoprotein B48.
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Notes:
    Summary In insulin-deficient streptozotocin-treated rats the intestine is hypertrophic and cholesterol synthesis and transport from the intestine are increased. The increased load of cholesterol is transported through the mesenteric lymph in chylomicrons. Clearance from plasma of injected chylomicrons is slowed in insulin-deficient rats, but the underlying mechanisms are currently unresolved. Hyperphagia may increase the size of chylomicrons which could contribute to defective chylomicron clearance in insulin-deficiency. In the present experiments we compared the size and number of chylomicrons in mesenteric lymph of control rats and diabetic rats infused with fat at two levels. In control and diabetic lymph-cannulated rats, as the infused dose of lipid increased the transport of triglyceride increased substantially compared with fasted rats. In contrast the transport of apoB48 increased by only a small amount during fat transport. Therefore, increased lipid transport was accomplished mostly by increased particle size, with only small increases in numbers of particles in intestinal lymph. Insulin-deficiency had no effect on triglyceride or apoB48 transport in lymph. Calculations suggested that each chylomicron particle contained a single molecule of apoB48. When hyperphagia in diabetic rats was prevented, the plasma triglycerides were decreased but the slow plasma clearance of injected chylomicron-like emulsions persisted. Hyperphagia, therefore, was unconnected to the impairment in chylomicron metabolism in insulin-deficient rats. Changes in the association with plasma apolipoproteins, in the expression of receptors for uptake of chylomicron remnants or in exposure to endothelial lipases may be responsible for the defective clearance of triacylglycerol-rich lipoproteins. [Diabetologia (1994) 37: 238–246]
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00398049

    Articles: DFG German National Licenses
  19. 19
    Staff View
    ISSN:
    1432-0428
    Keywords:
    Chylomicrons ; chylomicron remnants ; intestine ; diabetes mellitus ; apolipoprotein B48
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Notes:
    Summary In insulin-deficient streptozotocin-treated rats the intestine is hypertrophic and cholesterol synthesis and transport from the intestine are increased. The increased load of cholesterol is transported through the mesenteric lymph in chylomicrons. Clearance from plasma of injected chylomicrons is slowed in insulin-deficient rats, but the underlying mechanisms are currently unresolved. Hyperphagia may increase the size of chylomicrons which could contribute to defective chylomicron clearance in insulin-deficiency. In the present experiments we compared the size and number of chylomicrons in mesenteric lymph of control rats and diabetic rats infused with fat at two levels. In control and diabetic lymph-cannulated rats, as the infused dose of lipid increased the transport of triglyceride increased substantially compared with fasted rats. In contrast the transport of apoB48 increased by only a small amount during fat transport. Therefore, increased lipid transport was accomplished mostly by increased particle size, with only small increases in numbers of particles in intestinal lymph. Insulin-deficiency had no effect on triglyceride or apoB48 transport in lymph. Calculations suggested that each chylomicron particle contained a single molecule of apoB48. When hyperphagia in diabetic rats was prevented, the plasma triglycerides were decreased but the slow plasma clearance of injected chylomicron-like emulsions persisted. Hyperphagia, therefore, was unconnected to the impairment in chylomicron metabolism in insulin-deficient rats. Changes in the association with plasma apolipoproteins, in the expression of receptors for uptake of chylomicron remnants or in exposure to endothelial lipases may be responsible for the defective clearance of triacylglycerol-rich lipoproteins.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00398049

    Articles: DFG German National Licenses
  20. 20
    Daimon, T. ; Sano-Martins, I. S.
    Springer
    Published 1989
    Staff View
    ISSN:
    1432-119X
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Medicine
    Notes:
    Summary An attempt was made to demonstrate wheatgerm agglutinin (WGA) binding sites on platelet surfaces after thrombin stimulation, by means of a post-embedding cytochemical technique using colloidal gold as marker at an ultrastructural level. In unstimulated platelets washed with EDTA, an intense uniform labeling of WGA-gold complexes was found on the surface membrane. When washed platelets were stimulated by thrombin in the absence of Ca2+, only a release reaction was induced. WGA labeling on the surface membranes of these platelets decreased dramatically. However, the labeling intensity of WGA-gold complexes on the surface membrane of aggregated platelets induced by thrombin in the presence of Ca2+ increased significantly compared to that of thrombin-stimulated platelets in the absence of Ca2+. In contrast to the uniform labeling on the surface membranes of unstimulated platelets, clusters of gold label were often found on the surface membrane of the aggregated platelets, although there was no significant quantitative difference in the labeling intensity between these two groups. Thus, we present direct morphological evidence demonstrating qualitative and quantitative alterations of WGA labeling on the surface membrane of platelets after thrombin stimulation. The possibility is considered that WGA-binding glycoproteins in the surface membrane are involved in the aggregation response after thrombin stimulation.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00492516

    Articles: DFG German National Licenses