bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Remodeling in the Limb Circulation: Impact of Obesity and Diabetes
Authors: Stepp David W. , De Chantemele Eric J. Belin 
Published: July 2007

ABSTRACTObesity is an emerging epidemic worldwide and threatens cardiovascular health due to the complications of accompanying metabolic dysfunction. One potential mechanism by which these complications are advanced is structural alteration in the microcirculation perfusing target organs. In this brief review, the authors focus on the structural adaptations that occur in the microcirculation, with specific focus on changes in basement membrane thickness and vascular structure. By delineating changes in end‐stage disease and recent insights from animal studies, they hope to convince the reader (1) that diabetic disease in the limb is associated with profound changes in arteriolar structure and (2) that parallel changes in microvascular architecture precede the onset of frank type II diabetes.
Neurons in the cerebral cortex are most susceptible to DNA‐damage in aging rat brain
Authors: Mandavilli Bhaskar S. , Rao Kalluri Subba 
Published: July 2007

AbstractUsing nick translation type of incubation and terminal deoxynucleotidyl transferase catalyzed 3‐end labeling, single and double strand breaks in genomic DNA of permeabilised neurons from different regions of young, adult and the aged rat brain were assessed. A steady increase in both types of breaks is noted with advancement of age in all of the brain regions studied. However, the number of SSB encountered in the cerebral cortex was the maximum and was also markedly higher than that in other brain regions. When the neuronal cells were exposed to MNNG or Glutamate the damage was aggravated in all the regions and at all ages but the most severe SSB damage is present in the cerebral cortex of older animals. Both cerebral cortex and the hippocampus showed equally higher DSB in comparison with the other regions. It is concluded that with advancement of age, DNA‐damage accumulates in neurons and the cerebral cortex is the most vulnerable region.
Isolation of mammalian pol ß type DNA polymerase in shoot tips of germinated seedlings of IR‐8 rice (lOryaza sativa L.)
Authors: Sanathkumar Mokkapati , Ghosh Bharati , SenGupta Dibyendu N. 
Published: July 2007

AbstractA single polypeptide of approx. 67 kDa mol.wt. with DNA polymerase activity has been chromatographically purified from shoot tips of 72 hr. grown germinated seedlings of rice (lOryza sativa.L.cv IR‐8). An approx. 4800 fold enrichment of specific activity was measured by the incorporation of 3H‐dTMP into trichloroacetic acid insoluble fraction, using activated calf thymus DNA as template‐primer. The enzyme uses different types of DNA but not RNA as a template. The enzyme requires Mg++, high KCl, and is highly sensitive to dideoxyribonucleoside triphosphate but is unaffected by aphidicolin, suggesting a plant counterpart of mammalian DNA polymerase β. Replication of M13mp18 single stranded DNA by extension of 5′132P‐labeled 17‐mer primer(‐40) showed distributive type of DNA synthesis by the rice DNA polymerase β, which is a characteristic feature of mammalian DNA polymerase ß.
Phenylhydrazine causes sulfhydryl oxidation and protein aggregation in hemoglobin‐free human erythrocyte membranes
Authors: Hashmi Afshan N. , Saleemuddin M. 
Published: July 2007

AbstractPhenylhydrazine induces a remarkable decrease in total free sulfhydryls as well as spectrin and most other polypeptides in hemoglobin‐free human erythrocyte ghosts. A parallel increase in coomassie blue stainable material that was retained on the gel tops was also observed. EDTA but not DM protected the membrane from phenylhydrazine‐induced alterations, while antioxidants, catalase and SOD were ineffective. The aggregated material isolated from phenylhydrazine‐treated membranes could be partially dissociated in presence of β‐mercaptoethanol to yield most of the membrane polypeptides.
Partial characterization of the lysine rich 280KD globulin from common buckwheat (Fagopyrum esculentum Moench): Its antigenic homology with seed proteins of some other crops
Authors: Rout M. K. , Chrungoo N. K. 
Published: July 2007

AbstractA high molecular weight (HMW) globulin, the main storage protein in grains of the common buckwheat (Fagopyrum esculentum Moench) has been partially characterized. The protein exists as an oligomeric complex with molecular mass of 280 kD and is composed of three groups (α, β and γ of polypeptides with molecular weights ranging between 55‐60, 32‐44 and 16‐29 kD respectively. The protein showed serological cross reactivity with globulins of soya bean, mung bean and pea. Antibodies raised against the purified protein did not recognize the storage proteins from broad bean, rice, wheat and grain amaranth. The 280 kD globulin of buckwheat grains belongs to the legumin family of proteins.
Primary structures and sequence analysis of human ribosomal proteins L39 and S27
Authors: Tsui Stephen Kwok Wing , Lee Simon Ming Yuen , Fung Kwok Pui , Waye Mary Miu Yee , Lee Cheuk Yu 
Published: July 2007

AbstractWe report here the primary structures and sequence analysis of the human ribosomal protein L39 (hRPL39) and S27 (hRPS27). The hRPL39 cDNA is 352 bp in size encoding a predicted protein of 51 amino acids. The region KRRHWRRTKL near the carboxyl end is conserved between human, rat, maize, C. elegans and yeast. The hRPS27 cDNA is 321 bp in size encoding a deduced protein of 84 amino acids. When the deduced amino acid sequence of hRPS27 was compared with that of rat ribosomal protein S27 and human metalloproteinstimulin‐1 (MPS‐1), identity levels of 96.4% and 100% were obtained respectively. A potential polyadenylation signal AACAAA is found in the MPS‐1 cDNA but the more frequently used AATAAA sequence is present in the hRPS27 cDNA. The carboxyl‐terminal cysteine arrangement in hRPS27 is similar to the family of C4 zinc finger DNA‐binding proteins.
The relationships between biophysical activity and the secondary structure of synthetic peptides from the pulmonary surfactant protein SP‐B
Authors: Kang Joo Hyun , Lee Myung Kyu , Kim Kil Lyong , Hahm Kyung‐Soo 
Published: July 2007

AbstractSynthetic pulmonary surfactants consisting of a mixture of phospholipids with synthetic peptides based on human and bovine surfactant‐associated protein SP‐B were prepared. These surfactants were analyzed for their biophysical activities by Wilhemly balance experiments and for their secondary structures by circular dichroism (CD) spectroscopy. Four synthetic peptides (SP‐1, SP‐2, SP‐3, and SP‐4) combined with the phospholipid mixture displayed significant surfactant properties. The CD spectra showed that the α‐helical propensities of the peptides in SDS micelles were related to their surfactant activities. These results suggested that the several truncated peptides originated from SP‐B protein, when appropriately recombined with phospholipids, could be used as an effective synthetic surfactant for clinical use.
The interaction of 8‐anilinonaphthalene‐1‐sulfonate with His‐47 of Taiwan cobra phospholipase A2 perturbing by the binding of calcium ion
Authors: Chang Long‐sen , Chou Lidge , Lin Shinne‐ren , Chang Chun‐chang 
Published: July 2007

AbstractThe 8‐anilinonaphthalene‐1‐sulfonate (ANS) fluorescence intensity of ANS‐Naja naja atra (Taiwan cobra) phospholipase A2 (PLA2) complex increased with the addition of Ca2+, but the observed fluorescence enhancement markedly decreased after methylation of His‐47 in PLA2 molecule. However, the binding affinities of methylated PLA2 for ANS and Ca2+ were similar to or even greater than those observed with native PLA2. These results, together with the finding that ANS electrostatically interacted with His‐47 of PLA2, suggest that the increase in the intensity of ANS fluorescence upon the addition of Ca2+, in part, arises from the ionic interaction of His‐47 with ANS being perturbed by the binding of Ca2+.
What regulates respiration in mitochondria?
Authors: Korzeniewski Bernard 
Published: July 2007

AbstractA (nearly) linear dependence of the respiration rate on a given parameter value was proposed as the criterion for considering this parameter to be an efficient regulator of respiration in mitochondria. A number of possible candidates was tested using the dynamic model of oxidative phosphorylation developed previously, among others ADP, the ATP/ADP ratio, external phosphorylation potential and Atkinson's adenylate energy charge. Only the external phosphorylation potential log(ATP/ADP*Pi) was found to fulfil the above‐mentioned criterion and thus it was proposed to be the parameter which “actually” regulates oxidative phosphorylation in mitochondria.
Kinetic study on the irreversible thermal denaturation of lentil lectin
Authors: Shnyrov Valery L. , Marcos María J. , Villar Enrique 
Published: July 2007

AbstractThe irreversible thermal denaturation of lentil lectin was investigated at pH 7.4 using different techniques including high‐sensitivity differential scanning calorimetry, differential detergent solubility thermal gel analysis, intrinsic fluorescence and hemagglutinating activity assays. The shape of the transition, as well as its scan‐rate dependence, can be explained by assuming that thermal denaturation takes place according to the kinetic scheme N k→ D, where k is a first‐order kinetic constant that changes with temperature, as given by the Arrhenius equation, N the native state, and D the denatured one. On the basis of this model, the value of the rate constant as a function of temperature and the activation energy were calculated. The analytical data obtained with the other methods used in this work support the proposed two‐state kinetic model.
The role of chelators in the catalysis of glutathione‐γ‐glutamyl transpeptidase‐dependent lipid peroxidation by transition metals
Authors: Zalit Ilan , Glass George A. , Stark Avishay‐Abraham 
Published: July 2007

AbstractA γ‐glutamyl transpeptidase‐glutathione (GGT‐GSH) system induces transition metal‐dependent lipid peroxidation (LPO). The role of the transition metals iron and copper in this system was studied by determination of LPO rates, the rates of Fe3+ reduction, and the steady state concentration of Fe2+ as function of concentration of o‐phenanthroline or citrate. Optimum curves were obtained, compatible with the idea that Fe2+ chelated by an entity other than o‐phenanthroline or citrate is important in thiol‐driven LPO. Cu enhanced LPO at low concentrations, inhibited LPO at high ones, and catalytically elevated the steady state concentration of Fe2+. Relating the steady states of Fe2+ at various chelator concentrations with those of LPO rates, indicate that a Fe2+‐O‐O‐Fe3+ complex may not be the principal oxidizing entity. The above, and the resistance of LPO to catalase, superoxide dismutase and mannitol are compatible with the notion that the Fe which participates in redox cycles is chelated to an entity that may be refractory to the action of these antioxidants.
Free radical mediated membrane perturbation and inhibition of type‐I iodothyronine 5′‐monodeiodinase activity by lead and cadmium in rat liver homogenate
Authors: Chaurasia Shyam Sunder , Gupta Pratima , Kar Anand , Maiti Prasanta Kumar 
Published: July 2007

AbstractThe possible involvement of lipid peroxidation (LPO) in the lead (Pb) and cadmium (Cd) induced thyroid dysfunction with special reference to type‐I iodothyronine 5′‐monodeiodinase (5′‐D) activity was studied in rat liver homogenate. Peroxidative reactions involving membrane components were found to be markedly stimulated by chronic administration of Pb and Cd in rats. Metal induced inhibition in 5′‐D activity was also observed. Since LPO is primarily an outcome of free radical generation, we suggest metal induced free radical mediated inhibition of 5′‐D activity in rat liver homogenate. In addition, serum triiodothyronine (T3) and thyroxine (T4) concentrations were also decreased by metals.
Proline is a protein solubilizing solute
Authors: Samuel D. , Kumar T. K. S. , Jayaraman G. , Yang P. W. , Yu C. 
Published: July 2007

AbstractThe effect of proline on the prevention of trichloroacetic acid (TCA)‐induced protein precipitation is studied. It is found that proline at high concentrations (>4.0 M) completely prevents TCA‐induced precipitation of hen egg white lysozyme. Other osmolytes such as ethylene glycol, glycerol and sucrose fail to prevent the TCA‐induced precipitation of lysozyme. Viscosity and 1‐anilino‐8‐naphthalene sulphonic acid binding experiments suggest that proline at high concentration forms an ordered supramolecular assembly. Proline is shown to increase the solubility of protein due to formation of such higher order assemblies. A model of the supra‐molecular assembly of proline is proposed and a possible in vivo role of the increased levels of proline under water stress is discussed.
Inhibition of DNA primase by sphingosine and its analogues parallels with their growth suppression of cultured human leukemic cells
Authors: Tamiya‐Koizumi Keiko , Murate Takashi , Suzuki Motoshi , Simbulan Cynthia Marie G. , Nakagawa Masako , Takemura Masaharu , Furuta Keigo , Izuta Shunji , Yoshida Shonen 
Published: July 2007

AbstractSphingosine is a potent inhibitor of a mammalian DNA primase in vitro (Simbulan et al., Biochemistry 33, 9007‐9012, 1994). Here we measured the inhibition of DNA primase in vitro by 9 sphingosine‐analogues with respect to RNA primer synthesis and DNA primase‐dependent DNA synthesis, and their potencies of inhibition in vitro were compared with their in vivo effects on human leukemic cells. Sphingosine, phytosphingosine and N, N‐dimethylsphingosine strongly inhibited the activity of purified calf thymus DNA primase, and also inhibited the growth of human leukemic cell line HL‐60, exerting strong cytotoxicity. Dihydrosphingosine and cis‐sphingosine, which showed more subtle inhibition of DNA primase in vitro, moderately inhibited the cell growth in vivo and caused cell death. In contrast, N‐acyl‐, N‐octyl‐, and N‐acetylsphingosine (ceramides) showing little inhibition of DNA primase suppressed cell growth only slightly. HL 60 cell was arrested at Go/G1 phase by exogenously added sphingosine. From these results, it is suggested that DNA primase is one of targets of sphingosine, an effector molecule in apoptosis.
Effect of cyclic polylactates on tumor cells and tumor bearing mice
Authors: Takada Shigeo , Nagato Yasukazu , Yamamura Masaichi 
Published: July 2007

AbstractWe studied the effect of cyclic polylactates ranging in size from a degree of polymerization number of 3 to 13 on pyruvate kinase, lactic dehydrogenase, anaerobic glycolysis, growth of tumor cells and survival of tumor bearing mice. Pyruvate kinase and lactic dehydrogenase activities were both inhibited by cyclic polylactates, and the inhibition mechanism of cyclic polylactates on lactic dehydrogenase was noncompetitive. About half the anaerobic glycolytic activity of FM3A ascites tumor cells was inhibited and tumor cell growth was also effectively inhibited by cyclic polylactates. Mice, which were treated with cyclic polylactates after inoculation of FM3A ascites tumor cells lived significantly longer than mice, which were treated with vehicle or non mice.
Evidence for a direct interaction of superoxide anion radical with carnosine
Authors: Klebanov G. I. , Teselkin Yu.O. , Babenkova I. V. , Popov I. N. , Levin G. , Tyulina O. V. , Boldyrev A. A. , Vladimirov Yu.A. 
Published: July 2007

AbstractUsing photochemiluminescence, the interaction between carnosine and superoxide anion was measured directly. Carnosine at physiological concentrations decreased the amplitude of luminol chemiluminescence like superoxide dismutase (SOD) did, and prolonged the lag‐period of the chemiluminescence similar to the effect of ascorbic acid. From the interaction of nitro blue tetrazolium with superoxide anion generated by the xanthine oxidase system, the constant for interaction of carnosine with O2* was calculated to be 105 M‐1. sec‐1. The possible biological significance of the quenching of superoxide anion by carnosine is discussed.
Design of novel analogue peptides with potent fungicidal but low hemolytic activity based on the cecropin a‐melittin hybrid structure
Authors: Lee Dong Gun , Park Jung‐Hyun , Shin Song Yub , Lee Sung Gu , Lee Myung Kyu , Kim Kil Lyong , Hahm Kyung‐Soo 
Published: July 2007

AbstractIn order to design synthetic peptides with potent antifungal activity but low cytotoxic activity under physiological conditions, several analogues of the previously reported cecropin A (CA)‐melittin (ME) hybrid peptide, CA(1‐8)‐ME(1‐12), were synthesized. These analogues were designed by analysis of the α‐helical wheel diagram of CA(1‐8)‐ME(1‐12). Antifungal activities were measured by growth inhibition of the yeast Trichosporon beigelii and by hemolytic assay with human red blood cells, respectively. Substitution of Thr for Lys at position 18 and 19 of CA(1‐8)‐ME(1‐12) caused a dramatic reduction in hemolytic activity. Two analogue peptides (analogue I and III) showed more potent antifungal and lower hemolytic activity than the original peptide. To study the antifungal mechanism of these peptides, fluorescence activated flow cytometry and confocal laser scanning microscopy were performed with the most powerful antifungal analogue I peptide designed in the present study. As determined by propidium iodide staining, fungal cells treated with analogue I or melittin showed higher fluorescence intensity than those treated with the weak antifungal peptide, cecropin A. By confocal microscopy the analogue I was detected in the intracellular region as well as the in cell membrane. These facts suggested that the antifungal function of this novel peptide analogue acts by pore formation in the cell membrane.
Effects of ultraviolet‐B radiation on phycobilisomes of Synechococcus PCC 7942: Alterations in conformation and energy transfer characteristics
Authors: Sah Jerome F. , Krishna Kolli Bala , Srivastava Madhulika , Mohanty Prasanna 
Published: July 2007

AbstractPhycobilisomes (PBS), the major light harvesting antenna of the cyanobacterium Synechococcus contain phycocyanin (PC) and allophycocyanin (APC) as major pigment‐protein complexes. PBS also absorb ultraviolet‐B (280‐320 nm) radiation. Exposure of Synechococcus PBS to low dose of UV‐B (∼0.28 mw.cm‐2) for 90 min induced change in absorption, emission and excitation characteristics of PBS and these changes got enhanced after 3 h of exposure. Room temperature excitation and emission spectra clearly indicated uncoupling of energy transfer from PC to APC on exposure to UV‐B. Also, the 77K emission spectra suggested that F682 emission originating from APC decreased by 42% after 3 h of exposure. Circular dichroism (CD) spectra of UV‐B exposed PBS indicated changes (14% decrease) in the α‐helical content after 90 min treatment. SDS‐PAGE analysis indicated degradation of a 75 kDa polypeptide (which appear to be a linker polypeptide) on UV‐B treatment. The degradation of this polypeptide seems to induce changes in pigment‐protein interaction and decoupling of energy transfer within the PBS. Our results for the first time clearly indicate that the PBS of Synechococcus are targets for UV‐B damage.
The role of cationic amino acid residues in the lethal activity of stonustoxin from stonefish (Synanceja horridat) venom
Authors: Khoo Hoon‐Eng , Chen Desong , Yuen Raymond 
Published: July 2007

AbstractStonustoxin (SNTX) is a two subunit pore‐forming cytolytic protein purified from the venom of the stonefish (Synanceja horrida). SNTX also possesses lethal activity. Since cationic residues contribute significantly to the cytolytic activity of several pore‐forming toxins, we examined the role of lysine and arginine residues in the lethal activity of SNTX. SNTX lost its lethal activity when the positively‐charged side chains of lysine residues were converted to negatively‐charged side chains upon succinylation. When the arginine residues were modified using 2,3‐butanedione, SNTX also lost its lethal activity. However, the domains for cytolytic and lethal activity may not necessarily be the same.
Isolation and characterization of a new lectin from the venom of the snake Bothrops jararacussu
Authors: Carvalho D. D. , Marangoni S. , Oliveira B. , Novello J. C. 
Published: July 2007

AbstractBothrops jararacussu venom contains a new potent hemagglutinin (BJcuL), isolated by affinity chromatography on immobilized D‐galactose. Hemagglutination activity of BJcuL against pig erythrocytes was inhibited by galactosides, EDTA or EGTA. The purified lectin is a di sulfide dimer composed of 15 kDa subunits. Association of these subunits is essential for lectin activity, since DTT‐reduced BJcuL showed no hemagglutination activity against pig erythrocytes. Reduced and S‐pyridylethylated BJcuL (RP‐BJcuL) was separated as a single peak by reverse‐phase HPLC on a C‐18/μBondapak column. Results of the application of Edman degradation methodology showed that RP‐BJcuL has a single N‐terminal amino acid sequence, indicating that BJcuL is a homodimer. The N‐terminal 8‐residue (NNCPQDWL) shows homology with other lectins from snake venoms.
A novel tumor necrosis factor‐α mutant with significantly enhanced cytotoxicity and receptor binding affinity
Authors: Shin Nam‐Kyu , Lee Inkyoung , Chang Seung‐Gu , Shin Hang‐Cheol 
Published: July 2007

AbstractA novel tumor necrosis factor‐α mutant (mutant M3), in which Ser and Tyr at positions 52 and 56 were substituted by Ile and Phe, respectively, along with deletion of 7 N‐terminal amino acids, was prepared and its biological activities were investigated. The mutant exhibited a 14‐ to 24‐fold increase in the cytotoxicity relative to the wild‐type TNF on various cancer cell lines. The binding affinity of the mutant to TNF‐R55 and TNF‐R75 receptors was over 10‐fold higher than that of the wild‐type. TNF‐α and the mutant show similar CD spectra in the far‐UV region, indicating that the overall structure was not influenced by the mutations. The production of highly potent TNF‐α mutant utilizing increase of hydrophobicity in the region 52‐56 may provide a structural basis for a design of optimized TNF‐α as a therapeutic purpose.
Inhibitory effect of the leaf extract of Ginkgo biloba L. on oxidative stress‐induced platelet aggregation
Authors: Akiba Satoshi , Kawauchi Takashi , Oka Takashi , Hashizume Tsutomu , Sato Takashi 
Published: July 2007

AbstractThe effect of the leaf extract of Ginkgo biloba L. on platelet aggregation induced by oxidative stress was studied. The extract caused a dose‐dependent inhibition of platelet aggregation stimulated with tert‐butyl hydroperoxide (t‐BHP) and Fe2+. Similar inhibitory activity was observed when platelets were exposed to H2O2 and Fe2+. Synergistic aggregation induced by a combination of t‐BHP and Fe2+ or H2O2 and Fe2+ in association with suboptimal concentration of collagen or U46619, was prevented by the extract. However, the extract failed to inhibit aggregation in response to collagen, thrombin or U46619. Ginkgolides A, B and C inhibited platelet‐activating factor‐induced aggregation, but not oxidant‐induced aggregation. These data suggest that the suppressive effect of the extract is specific on platelet aggregation stimulated by oxidative stress, and that this effect is involved in the mechanism related to its protective effect upon cerebral or myocardial injuries.