bluuebunny/crossref_metadata_2025_split huggingface dataset:
Group specific antibodies against the putative AMP‐binding domain signature SGTTGXPKG in peptide synthetases and related enzymes
Authors: Etchegaray Augusto , Dieckmann Ralf , Engel Paul C. , Turner Geoffrey , Döhren Hans 
Published: July 2007

AbstractThe superfamily of adenylate forming enzymes including peptide synthetases, acyl‐CoA synthetases and insect luciferases is readily identified by the signature sequence SGTTGXPKG. This sequence including an invariant lysyl residue is located in a disordered loop region and was predicted to be of significant antigenicity. Antibodies were generated employing YTSGTTGRPKGC attached to bovine serum albumin and have been successfully used to identify respective enzymes and adenylate forming domains in multienzyme systems. These include the δ‐(L‐α‐aminoadipyl)‐L‐cysteinyl‐D‐valine synthetases of Aspergillus nidulans and Acremonium chrysogenum, gramicidin S synthetase 1 and tyrocidine synthetase 1 from Bacillus brevis, acetyl‐CoA synthetase from Alcaligenes eutrophus and a putative peptide synthetase from Metarhizium anisopliae. Weaker or no reactions are observed when the amino acid in position X in the protein is non‐basic or hydrophobic, which is respectively the case for gramicidin S synthetase 1 and luciferase.
An archaeal DNA binding protein from thermophilic Sulfolobus acidocaldarius forms different types of complexes with DNA
Authors: Sreenivas Kanugula , Jaya K. S. , Suryanarayana Tangirala 
Published: July 2007

AbstractWe have characterized a DNA binding protein (DBNP‐B) from the thermoacidophilic archaeon Sulfolobus acidocaldarius with respect to its interaction with single and double stranded DNA. The protein in solution exists predominantly as dimer as indicated by cross linking studies. Binding of DBNP‐B to etheno DNA and poly (dA) resulted in fluorescence enhancement and hyperchromicity respectively. Ethidium bromide intercalated into DNA was completely displaced by DBNP‐B. DNase I digestion of dsDNA was increased at subsaturating concentration of the protein and was inhibited at higher concentrations. These results and electron microscopy indicate that the protein forms different types of novel complexes with DNA at different protein to DNA ratios.
Induction of buccal mucosal apoptosis with chronic alcohol ingestion
Authors: Slomiany B. L. , Piotrowski J. , Piotrowski E. , Slomiany A. 
Published: July 2007

AbstractIn this study we investigated buccal mucosal cells' apoptosis and the expression of regulatory cytokines, tumor necrosis factor‐α (TNF‐α) and inetrleukin‐4(IL‐4) with chronic ethanol ingestion. The buccal mucosa of rats maintained for 23 days on alcohol‐containing and control liquid diet was assessed for IL‐4 and TNF‐α content, and the extent of epithelial cells apoptosis. While the expression of TNF‐α in alcohol diet group showed a significant increase (1.9‐fold) over that of the controls, less apparent differences between the two groups were observed in the content of IL‐4 (141.8±28.2 vs. 119.8±7.3 pg/mg protein). The DNA fragmentation assays revealed that alcohol diet group also exhibited a 3.5‐fold enhancement in buccal mucosal cells apoptosis. Moreover, the apoptotic index showed positive correlation (r=0.53) with the extent of induced changes in TNF‐α. These results demonstrate that ethanol‐induced buccal mucosal cells apoptosis is triggered by the enhancement in TNF‐α expression.
Midkine induces histamine release from mast cells and the immediate cutaneous response
Authors: Hiramatsu Kenju , Yoshida Hiroshi , Kimura Tomoki , Takagi Kenzo 
Published: July 2007

AbstractMidkine is a product of a retinoic acid‐responsive gene and exerts a variety of biological activities. The aim of our investigation is to determine whether human midkine have histamine‐releasing effects on mast cells, and to show the evidence of the inflammation induced by midkine. Midkine induced histamine release from rat peritoneal mast cells with a rapid response in a dose‐dependent manner. Extracellular calcium inhibited the histamine release induced by midkine in a dose‐dependent manner. Pertussis toxin and benzalkonium chloride inhibited the histamine release induced by midkine. Gi‐proteins exert an effect on the histamine release of midkine. The immediate cutaneous response induced by midkine was positive. These results suggest that midkine may take part in some inflammation via histamine release from mast cells.
Responses of intestinal and renal alpha‐glycosidases to alloxan and streptozotocin‐induced diabetes: A comparative study
Authors: Sharma Suresh D. , Sivakami S. 
Published: July 2007

AbstractExperimentally induced diabetes in the rat resulted in an increased level of alpha‐glycosidases in the intestine but a depression in their levels in the kidney. Rat intestine exhibited a differential stimulation of maltase, sucrase and trehalase activities. The variations depended on the duration of diabetes and the β‐cytotoxic compounds used i.e. alloxan and streptozotocin. The maximum elevation in terms of total units and specific activity was observed on the 30th day in the following order: maltase>sucrase>trehalase. A significant observation emerging from this study is that the level of intestinal enzymes increases while that of the kidney enzymes declined during the period. Although intestinal and renal alpha‐glycosidases are known to be structurally and biochemically similar, their opposing responses to diabetes indicates that they are under different regulatory mechanisms in these tissues.
Partial characterization of the lipopolysaccharides of peanut specific Bradyrhizobium strains
Authors: Jayaraman Vani , Das Hasi R. 
Published: July 2007

AbstractHexoses, heptose, hexuronic acids, 2‐keto‐3‐deoxyoctonic acid (Kdo) contents of the lipopolysaccharides (LPS) isolated from peanut (A. hypogaea) specific Bradyrhizobium strains NC 92, IGR 92, IGR 40 and IGR 6 were found to vary considerably. Sodium dodecyl sulphate polyacrylamide gel electrophoresis showed a heterogenous LPS population and distinct heterogenity was observed in NC and IGR strains. Sepharose gel filtration chromatography removed the hexose contaminants from NC 92 LPS. Polysaccharides obtained by mild acid hydrolysis of Sepharose purified NC 92 LPS were further purified on Sephadex G‐50 gel filtration. Immunoblot analysis indicated cross reactivity amongst the peanut specific Bradyrhizobium strains but not with B. japonicum(SB 16). Antibodies raised against native NC 92 LPS showed higher binding towards the Sephadex purified polysaccharides suggesting the antigenic property of polysaccharide moiety in LPS molecule.
A proposed position of a disulfide bridge in the molecules of cinnamomin and porrectin ‐ two new type II ribosome‐inactivating proteins isolated from the seeds of camphor trees
Authors: Liu Wang‐Yi , Chen Huai‐Yang , Chen Wen‐Feng , Li Xiang‐Dong , Ulbrich Norbert , Schröder Werner 
Published: July 2007

AbstractThe N‐terminal amino acid sequences of A‐ and B‐chains of three isoforms of cinnamomin and porrectin ‐ two new type II ribosome‐inactivating proteins purified from the seeds of camphor trees have been compared with themselves and with that of ricin and abrin. It has completely homologous sequence of A‐chain of six isoforms, and the same of six B‐chain sequences. However, among 10 amino acids of the N‐terminal sequence of the A‐chain there is only 20% homology between cinnamomin/porrectin and abrin, no homology between cinnamomin/porrectin and ricin. In their B‐chain, there are 60% homology between cinnamomin/porrectin and ricin, the fourth position is always occupied by cysteine. Compared with that of ricin/abrin, we proposed that the position of a disulfide bridge is at fourth cysteine in the B‐chain of cinnamomin/porrectin and a cysteine nearby the C‐terminus of A‐chain of cinnamomin/porrectin.
An extremely high conservation of RNA‐protein S7 interactions during prokaryotic ribosomal biogenesis
Authors: Spiridonova Vera A. , Golovin Andrey V. , Drygin Denis Yu. , Kopylov Alexei M. 
Published: July 2007

AbstractDirect determination of RNA‐protein complex structures is often facilitated by the use of thermophilic proteins; however E.coli is the most investigated system so far. A hybrid approach is to form heterologous complexes of E.coli RNA with thermophitic proteins. The rationale for this approach to RNA‐protein interactions in ribosomes is based on the ability of the thermophilic protein S7 to replace a homologous counterpart in vivo. In vitro, the protein S7 of Thermus thermophilus is able to form complexes with both the minimal 16S rRNA fragment and the intercistronic region of the str operon mRNA from E.coli (Kd=1.4×10‐7 M and 1.1×l0‐7 M respectively). The interaction of Thermus S7 with the E. coli intercistronic mRNA is surprising, because this region does not exist in the thermophilic str operon. It suggests a high degree of conservation of an RNA‐binding site on S7.
HPLC and light scattering detection allow the determination of phospholipids in biological samples and the assay of phospholipase A2
Authors: Landi Laura , Galli Maria Cristina , Cabrini Luciana , Hakim Gabriele , Carru Ciriaco , Fiorentini Diana 
Published: July 2007

AbstractSome applications to biological samples of a method for the separation and the quantitative analysis of phospholipids by high performance liquid chromatography (HPLC) and light scattering mass detection are described. Results obtained in the determination of phospholipid classes from rat tissues such as liver, heart and kidney have been compared with data from the literature. The method has been applied to the evaluation of phospholipids in human low‐density lipoproteins (LDL), about which little is known. The procedure is also suitable for a rapid and reliable assay of the water‐soluble phospholipase A2 activity; the relationship between the aggregation state of substrate phospholipids (mixed micelles, multilamellar and unilamellar vesicles) and the enzyme activity has been studied.
Starvation induced hypothyroidism involves perturbations in thyroid superoxide‐sod system in pigeons
Authors: Prakash Prem , Laloraya Malini , Kumar G Pradeep 
Published: July 2007

AbstractThis study investigated the influence of starvation over seven days on avian thyroidal superoxide radical levels and superoxide dismutase activity profiles in the Indian rock pigeon Columba fivia intermeida, in relation with iodine metabolism. The serum thyroid hormone profile was assayed to correlate the thyroidal redox status with the circulating thyroid hormone levels. The spin‐trapping results suggest a role for thyroidal superoxide anion (O2‐) in causing a hypothyroid state in pigeons during long term energy withdrawal. Pigeons starved for 1 day generated superoxide and iodide free radicals in their thyroids, with a significant decrease in SOD activity. Regain of SOD activity in 2nd‐ and 3rd‐day starved birds is marked by complete scavenging of radicals in the thyroid, suggesting the significance of SOD in thyroid glands as a potential antioxidant sink against reactive oxygen species, O2‐. Resurgence of 02‐ radicals with a parallel decrease in SOD activity in the thyroid gland on 5th‐ and 7th‐day of starvation provides evidence of disruption of homeostasis between pro‐oxidant and antioxidant states, leading to oxidative stress in avian thyroid during long‐term calorie crisis. Following starvation both thyroid hormones thyroxine (T4) and triiodothyronine (T3) decreased, putting pigeons in a hypothyroidstate. We argue that oxidative inactivation of thyroid peroxidase and other thyroid proteins by radical attack during starvation invoked oxidative stress, which could be one of the factors responsible for the hypothyroid state in pigeons.
A novel method for selection of chymotrypsin inhibitors from a phage peptide library
Authors: Liu Ying , Li Bin , Zhang Shu , Li Tianyu , Zhou Hui , Li Wei , Smith Ross , de Jersey John 
Published: July 2007

AbstractA novel screening strategy has been developed for the identification of α‐chymotrypsin inhibitors from a phage peptide library. In this strategy, the standard affinity selection protocol was modified by adding a proteolytic cleavage period to avoid recovery of α‐chymotrypsin substrates. After four cycles of selection and further activity assay, a group of related peptides were identified by DNA sequencing. These peptides share a consensus sequence motif as (S/T)RVPR(R/H). Then, a corresponding short peptide (Ac‐ASRVPRRG‐NH2) was synthesized chemically and proved to be an inhibitor of α‐chymotrypsin. The present work provides a useful way for searching proteinase inhibitors without detailed knowledge of the molecular structure.
Acrosome reaction inducers impose alterations in repulsive strain and hydration barrier in human sperm membranes
Authors: Purohit Sharad B. , Laloraya Malini , Kumar Pradeep G. 
Published: July 2007

AbstractSpin labeling studies of the lipophilic domains of human spermatozoa during capacitation and during acrosome reaction (AR) under the influence of selected AR‐inducers were performed. Significantly enhanced rotational function of molecules was obvious during capacitation, with no significant changes in membrane packaging or the lateral diffusion of molecules. The AR inducers appeared to restrict the rotational freedom of molecules, dramatically enhancing the lateral diffusion and ordering coefficients. A significant decrease in superoxide anion generation was observed in the acrosome reacted groups when compared to the non‐acrosome reacted groups. A high level of superoxide anion radical (O2‐) level maintained in capacitated spermatozoa would add to the Van der Waal's repulsive forces at the polar head of phospholipids, holding the membrane in strain where the molecular enjoy little freedom for lateral motion. A sudden drop in the levels of O2‐ in spermatozoa upon addition of AR inducers could abruptly release the local hydrophobic repulsive strain within the membrane. This loss of hydration barrier explains the observed enhancement in lateral diffusion profiles of lipids and the packaging of molecules. It is reasonable to assume that these phenomena could be amplified further by interplay of Ca2+ by modifying the local charge aggregation. Thus, we would conclude that AR inducers release the oxyradical load in capacitated spermatozoa, which would modify the repulsive strain and hydration barrier forces in the lipophilic domains permitting vesiculation of the membranes. It appears that various acrosome reaction inducers act as effectors of grossly similar physical alterations in sperm membranes and that the resulting signal cascades proceed through intercalating biochemical sequences.
60K gelatinase in involuting rat mammary gland is produced as a 90K proenzyme
Authors: Ambili M. , Sudhakaran P. R. 
Published: July 2007

AbstractThe matrix metalloproteinases appear to play a key role in mammary tissue remodeling during involution. By immunoprecipitation and immunoblot using antibodies against 60K gelatinase which appears during involution, a 90K polypeptide has been identified as its inactive proenzyme in the early involuting rat mammary gland. 90K polypeptide was isolated from the second day involuting rat mammary gland by immunoaffinity chromatography. On proteolytic digestion, the inactive 90K polypeptide was converted to active gelatinase. Primary cultures of mammary epithelial cells secreted the 90K polypeptide. These results indicated that the 60K inducible MMP involved in mammary gland involution and remodeling is produced as a 90K proenzyme which is activated by proteolysis in the extracellular sites.
Cloning and characterization of the upstream region of Clostridium botulinum type B neurotoxin gene
Authors: Yang Gi‐Hyeok , Rhee Sang Dal , Jung Hyun Ho , Jhee Ok Hwa , Yang Kyu‐Hwan 
Published: July 2007

AbstractThe upstream region of the gene coding for Clostridium botulinum type B (BoNT/B) neurotoxin was cloned and sequenced. There were two open reading frames, which were identified as a nontoxic‐nonhemagglutinin component (ntnh/B) and a 22 kDa adjacent open reading frame (orf22/B). Deduced primary structure of ntnh/B showed that it was composed of 1,197 amino acid residues. Pairwise comparisons of the ntnh/B component with other botulinum toxin types showed high degree of homology to ntnh/A (82% identity). Northern blot analysis revealed that toxin gene could be transcribed alone or co‐transcribed with the ntnh gene. The orf22/B gene encoding for 178 amino acids (M.W. 21.6 kDa) was located between the 33 kDa hemagglutinin gene and the ntnh gene. Orf22/B also showed high degree of homology to orf22/A (98.9% identity). These results suggested that the upstream region of the BoNT/B gene (containing the ntnh/B and orf22/B genes) might be evolutionarily closely related to the counterparts of the BoNT/A.
Isolation of two chymotrypsins from grass carp
Authors: Fong Wing‐Ping , Chan Elaine Yee‐Man , Lau King‐Kwan 
Published: July 2007

AbstractTwo chymotrypsins were purified from the hepatopancreas of grass carp (Ctenopharyngodon idellus) by chromatographies on phenyl‐Sepharose and Q‐Sepharose. The molecular weights of chymotrypsins I and II were 28 and 27 kDa, respectively. The two chymotrypsins showed similar susceptibility to inhibitions by phenylmethylsulfonyl fluoride and soybean trypsin inhibitor, but differed in their response to tosyl‐L‐phenylalanine chloromethyl ketone and aprotinin in which chymotrypsin I was more resistant. Chymotrypsin I was a less typical chymotrypsin and exhibited lower catalytic efficiency with the chymotrypsin‐specific ester and amide substrates, when compared with chymotrypsin II. For both chymotrypsins, optimal activity was detected in the pH range 7.0‐8.5.
Dual effect of 2‐deoxy‐D‐glucose tetraacetate upon glucose‐induced insulin release
Authors: Malaisse Willy J. , Flores Luis E. , Kadiata Marcel M. 
Published: July 2007

AbstractThe effect of 2‐deoxy‐D‐glucose tetraacetate upon glucose‐stimulated insulin release was explored in pancreatic islets from either normal or hereditary diabetic rats. At a high concentration (10 mM), it decreased the secretory response to D‐glucose, such an inhibitory effect being more marked in the case of the α‐ than β‐anomer of the ester. At lower concentrations (0.19 to 1.7 mM), however, 2‐deoxy‐D‐glucose tetraacetate augmented insulin secretion evoked by 8.3 mM D‐glucose, with again a preference for the α‐anomer of the ester. In relative terms, such an enhancing action was more marked in Goto‐Kakizaki than normal rats. Hence, it is proposed that selected esters of non‐nutrient carbohydrates could be used as insulinotropic tools in the treatment of non‐insulin‐dependent diabetes mellitus.
Involvement of ras and map kinase (ERK‐1) in cisplatin‐induced activation of murine bone marrow‐derived macrophages
Authors: Shishodia Shishir , Sodhi Ajit , Shrivastava Anju 
Published: July 2007

AbstractCisplatin (cis‐diamminedichloroplatinum II), a potent antitumor compound, stimulates immune responses by activating monocytes/macrophages and other cells of the immune system. However, the mechanism by which cisplatin activates these cells is poorly characterised. Our earlier findings indicate that cisplatin treatment stimulates rapid tyrosine phosphorylation in a number of cellular proteins in murine macrophages. This initial tyrosine phosphorylation is an important regulatory mechanism and is followed by activation of several other proteins. In the present study, we report the involvement of other key molecules and the role of tyrosine phosphorylation in their activation in the signaling cascade of cisplatin. We observed the involvement of Ras (a low molecular weight GTP‐binding protein) and ERK‐1 (a MAP kinase) in this signaling cascade. Cisplatin treatment results in an increase in the expression of both Ras and ERK‐1 in a dose‐dependent manner, which was dependent upon tyrosine phosphorylation. Genistein a PTK inhibitor inhibited the cisplatin induced expression of Ras and ERK‐1. These findings indicate that Ras and ERK‐1 are important signaling molecules involved in the tumoricidal activation of macrophages with cisplatin and is dependent on initial tyrosine phosphorylation.
Inhibition of proton transport through spinach thylakoid membranes by 5,5′‐dithiobis(2‐nitrobenzoate)
Authors: Ho John W. , Ho Alex W. 
Published: July 2007

AbstractIn both oxidative phosphorylation and photo‐phosphorylation, electron flow through a carrier is linked to the generation of ATP. The energy released by electron transport is converted to potential energy forming a proton gradient across the membranes in chloroplasts. The proton gradient can be measured by a pH microelectrode. In this report, pH changes produced by photo‐induced proton transport through spinach chloroplast membranes were measured by a glass microelectrode. The effect of 5,5′‐dithiobis(2‐nitrobenzoate) (DTNB) on the kinetics of proton movement across the thylakoid membranes was studied. The results showed that the rate of proton uptake was reduced with increasing DTNB concentration. The rate of leakage of accumulated protons through thylakoid membranes also decreased. The results support the notion that cysteinyl residue is involved in proton translocation. The inhibition of proton transport would subsequently affect the chemical reactions of the Calvin Cycle that takes place in the stroma which is the soluble compartment surrounding the thylakoid membranes.
The absence of strand‐specific repair for the DNA polymerase pol gene in Deinococcus radiodurans
Authors: Lin Chan‐Shing , Wang Hsiu‐Chin , Wong Tit.Yee. , Liu Jong‐Kang 
Published: July 2007

AbstractDeinococcus radiodurans is characterized by its extreme resistance to ionizing radiation. Although Mn+2 was taken up by the cells at a high speed, the absorption of Mn+2 by the cells did not affect their survival rate when irradiated by UV light. However, the Mn‐induced‐cell‐division (Mn‐CD) cells do lose their resistance to UV radiation. This can be explained by the fact that the Mn‐CD cells were less efficient to remove pyrimidine dimers on damaged DNA. We also found that there is no strand‐specific repair of the pol gene in this organism.
Effects of estradiol and progesterone on cytochrome P4501A1 expression in Hepa 1c1c7 cells
Authors: Lee Sang Seop , Jeong Hye Gwang , Yang Kyu‐Hwan 
Published: July 2007

AbstractThe effects of estradiol and progesterone on the expression of cytochrome P4501A1 were investigated in Hepa lclc7 cells. Both steroids, at 10 μM concentration, increased P4501Al‐mediated 7‐ethoxyresorufin O‐deethyalase activity and amounts of its immunoreactive protein and CYP1AI mRNA Gel shift assay revealed that the steroids could induce both AhR transformation and binding of the ligand‐AhR complex to its specific DNA recognition site. Transient transfection demonstrated that 5′flanking region of CYP1A1 could respond to the steroid action. The competitive binding assay showed that the steroids bound to AhR with moderate affinity. These results suggested that steroidal structure can be AhR ligands and induce CYP IAI expression in AhR‐dependent manner.
Inhibition of lung surfactant secretion by KN‐62, a specific inhibitor of the calcium‐ and calmodulin‐dependent protein kinase II
Authors: Liu Lin 
Published: July 2007

AbstractA role of Ca2+‐ and calmodulin‐dependent protein kinase II (CaMK II) in lung surfactant secretion was evaluated using KN‐62, a specific inhibitor of CaMK II. KN‐62 caused a dose‐dependent inhibition of Ca2+ iononphore A23187‐stimulated phosphatidylcholine (PC) secretion from cultured alveolar type II cells. Concentration effecting 50% inhibition was ∼4 μM. However, KN‐62 only slightly influenced PC secretion from type II cells stimulated by phorbol 12‐myristate 13‐acetate, terbutaline and ATP that are known to increase surfactant secretion via the protein kinase C and protein kinase A pathways. KN‐62 also inhibited the activity of CaMK II in type II cells. A 55 kDa protein was detected in type II cells by Western blot analysis using an antibody against the β‐subunit of CaMK II. The results suggest that CaMK II participates in A23187‐stimulated lung surfactant secretion.