Biochem Mol Biol Int
· 1999 Feb · PMID 10205662
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The physiological role of lactoferrin (LF) is still unclear, but it has been suggested to be responsible for primary defence against microbial infections. Many different unique functions have been attributed to LF, inclu...The physiological role of lactoferrin (LF) is still unclear, but it has been suggested to be responsible for primary defence against microbial infections. Many different unique functions have been attributed to LF, including DNA and RNA binding, and transport into the nucleus, where LF binds to specific DNA sequences and activates transcription. Here we present evidence that in addition to the above (and below) mentioned functions LF binds ATP with a stoichiometry of 1 mole of nucleotide per mole of the protein and a Kd = 0.3 mM. The ATP-binding site is localized in the C-terminal domain of LF, in contrast to the antibacterial and polyanion-binding sites, which are located in the N-terminal domain. Binding of ATP by LF leads to dissociation of its oligomeric forms and to a change of the protein's interaction with polysaccharides, DNA and proteins.
Vásquez C, Saavedra C, Loyola C
… +2 more, Moscoso H, Pichuantes S
Biochem Mol Biol Int
· 1999 Feb · PMID 10205661
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A potassium tellurite-resistance determinant was isolated from Bacillus stearothermophilus V and cloned in Escherichia coli. Transformed cells formed black colonies when grown on solid media containing permissive telluri...A potassium tellurite-resistance determinant was isolated from Bacillus stearothermophilus V and cloned in Escherichia coli. Transformed cells formed black colonies when grown on solid media containing permissive tellurite concentrations. The resistance determinant was contained in a B. stearothermophilus V chromosomal DNA fragment of 7 kb.
Biochem Mol Biol Int
· 1999 Feb · PMID 10205660
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Five antibodies against vascular endothelial growth factor 165 (VEGF165) were obtained. These antibodies, Ab-2, Ab-20, Ab-153, Ab-309, Ab-342, were able to recognize not only native VEGF165, but also reducing VEGF165. Th...Five antibodies against vascular endothelial growth factor 165 (VEGF165) were obtained. These antibodies, Ab-2, Ab-20, Ab-153, Ab-309, Ab-342, were able to recognize not only native VEGF165, but also reducing VEGF165. Three of the antibodies, Ab-153, Ab-309, Ab-342, were identified as VEGF165 neutralizing antibody on the basis of its ability to inhibit the proliferation of human umbilical vein endothelial cells (HUVEC) induced by VEGF165 and the binding of [125I]-VEGF165 to receptors on HUVEC. The fragments of E1 (VEGF120-135) and E2 (VEGF46-60) recognized by neutralizing antibodies may be related the receptor binding domain of VEGF.
Malini T, Arunakaran J, Aruldhas MM
… +1 more, Govindarajulu P
Biochem Mol Biol Int
· 1999 Mar · PMID 10204091
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Effects of piperine at two oral doses (5 and 10 mg/kg body weight for 30 days) on the lipid composition and some lipogenic enzymes of the rat testis were studied. Piperine treatment depleted the total lipid content which...Effects of piperine at two oral doses (5 and 10 mg/kg body weight for 30 days) on the lipid composition and some lipogenic enzymes of the rat testis were studied. Piperine treatment depleted the total lipid content which was mainly due to the diminution of the total phospholipid concentration. All the classes of phospholipids were decreased markedly following high dose piperine treatment. In contrast, a marked increase in total cholesterol and cholesterol ester was evident with a concomitant fall in free cholesterol. A similar trend was found for the total glyceride glycerol and its fractions. Total glyceride glycerol and triacyl glycerol showed a significant increase at the expense of diacyl glycerol in rats treated with the high dose of piperine. Lipogenic enzymes, malate dehydrogenase (MDH), malic enzyme (ME) and isocitrate dehydrogenase (ICDH) were inhibited by the high dose and only MDH and ME activities were inhibited by the low dose treatment.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204090
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The involvement of glutamate in PAF-increased cyclic GMP levels was studied. Glutamate treatment caused a dose-response increase of cyclic GMP levels in hippocampal slices. The presence of 1 mM glutamate did not modify t...The involvement of glutamate in PAF-increased cyclic GMP levels was studied. Glutamate treatment caused a dose-response increase of cyclic GMP levels in hippocampal slices. The presence of 1 mM glutamate did not modify the effect caused by 10(-7)M PAF. To elucidate the involvement of glutamate in this action, slices were treated with PAF in the presence of MK-801, a NMDA receptor antagonist. Results indicate that PAF-increased cyclic GMP levels were obtained by NMDA receptors activation. Finally, results obtained from the experiments performed with PAF in the presence of riluzole, to inhibit the glutamate release, demonstrated that glutamate release is a stage in the PAF-induced increase of cyclic GMP levels in hippocampus.
Pispirigos K, Simopoulos K, Kouskoukis K
… +2 more, Kounis N, Avramopoulos A
Biochem Mol Biol Int
· 1999 Mar · PMID 10204089
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Renal and hepatic subacute toxicity induced by the antihyperlipidaemic drugs: Bezalip-Pravastatin and Lopid was investigated in rats using serum biochemical parameters. Toxicological evaluation was performed in serum sam...Renal and hepatic subacute toxicity induced by the antihyperlipidaemic drugs: Bezalip-Pravastatin and Lopid was investigated in rats using serum biochemical parameters. Toxicological evaluation was performed in serum samples following the administration of the therapeutic dose regimens of the compounds that were previously shown to be effective in inhibition of 3-hydroxy-methylglutaryl coenzyme A (HMG CoA) reductase, the enzyme controlling the rate-limiting step in the synthesis of cholesterol, and acyl-CoA cholesterol acyl transferase (ACAT) which converts intracellular free cholesterol to cholesterol ester. Renal and hepatic subacute toxicity was evaluated by measuring enzyme activity or concentrations of: alanine aminotransferace, alkaline phosphatase, aspartate aminotransferase, gamma-glutamyltransferase, glucose, potassium, sodium, blood urea nitrogen, uric acid and creatinine. The use of the above serum biochemical parameters indicated that the overall toxicity impact of antihyperlipidaemic drugs was Bezalip = Pravastatin < Lopid. We have found that the Pravastatin--in contrast to the above antihyperlipidaemic drugs--only transiently affects the biochemical parameters associated with toxicity, but, it affects some of the biochemical parameters associated with hepatic and renal toxicity, up to a significantly lower extent than the antihyperlipidaemic drugs.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204088
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The percent solubility at 34 degrees C (skin temperature) of radioactive tocopherol succinate was determined for a number of edible oils, and a semisynthetic oil, Myritol 318 (Henkel, Kankakee, IL, a medium chain triglyc...The percent solubility at 34 degrees C (skin temperature) of radioactive tocopherol succinate was determined for a number of edible oils, and a semisynthetic oil, Myritol 318 (Henkel, Kankakee, IL, a medium chain triglyceride prepared from fractionated coconut oil). Its solubility in Myritol 318 was approximately 50% better than any of the other oils. 14C-tocopherol succinate was diluted (1) into pure Myritol 318, a cosmetic base or (2) 50% tocopherol succinate in Myritol 318. These preparations were applied topically to a 2 cm diameter circle of the back saddle skin of a hairless mouse (strain skh-1). After 24 hr, up to 65% of the label was absorbed by the skin and was also found in skin removed from areas of the back other than the application area, and internal organs such as liver and heart. Up to 6% was hydrolysed to free tocopherol. Topical treatment may be an alternative to oral administration in gastrointestinal malabsorption diseases.
Chakraborti T, Mandal M, Das S
… +1 more, Chakraborti S
Biochem Mol Biol Int
· 1999 Mar · PMID 10204087
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Arachidonic acid (AA) metabolism was assessed in cultured alveolar macrophages (AM) obtained from newborn (10 days old) and adult (2 months and 4 months old) rats. The AMs were stimulated with the calcium ionophore, A231...Arachidonic acid (AA) metabolism was assessed in cultured alveolar macrophages (AM) obtained from newborn (10 days old) and adult (2 months and 4 months old) rats. The AMs were stimulated with the calcium ionophore, A23187 (10 microM). The released radiolabelled AA metabolites were measured by thin layer chromatography. The results showed that among different aged rats, the synthesis of 5-lipoxygenase (5-LO) metabolites, LTB4, LTC4, LTD4 and 5-HETE were increased with age inspite of similar levels of [14C]AA release. In response to A23187, 5-LO metabolic capacity of 2 and 4 months old adult rat AMs were increased 21-fold and 34-fold, respectively, compared with 10 days old rat AMs. As the metabolic capacity increased, the release of prostaglandins and thromboxane B2 tended to decrease markedly. Newborn rats (10 days old) AM, at the initial developmental stage, did not produce a noticeable amount of 5-LO metabolites which, conceivably, contribute to high susceptibility of neonatal lung to infection.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204086
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The gene sequence encoding the non-catalytic heavy chain of mouse complement factor I (mCFI) was cloned and its exon-intron organization and domain structure characterized. The genomic organization of mCFI differs in sev...The gene sequence encoding the non-catalytic heavy chain of mouse complement factor I (mCFI) was cloned and its exon-intron organization and domain structure characterized. The genomic organization of mCFI differs in several aspects from its human homologue (hCFI). The intron sizes are remarkably different. Exons 2 and 4 in mCFI are larger than their counterparts in hCFI by 9 bp and 6 bp respectively. Whereas the diversity (D) region of hCFI is encoded by two exons (exon 7 or hD2 and exon 8 or hD4), this region in mCFI is encoded by three exons; exon 6A or mD1 (located at the 3'-end of the LDLr A2 domain), exon 7 or mD2 and exon 8, an extended exon (56 bp) composed of mD3, fused upstream of mD4. In contrast, hCFI lacks D1 and D3 subregions and exon 8 in hCFI consists of only hD4, 36 bp in length. Thus the heavy chain of mCFI is organized into 10 exons compared to 9 exons in hCFI.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204085
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Germ cells are known to regulate Sertoli cell and testicular function possibly through released factor(s) or via cell-cell contact. However, the identities of many of these putative biological factors are not known. The...Germ cells are known to regulate Sertoli cell and testicular function possibly through released factor(s) or via cell-cell contact. However, the identities of many of these putative biological factors are not known. The aim of this study is to present a strategy to identify and purify germ cell-derived proteins found in germ cell-conditioned medium (GCCM) at a quantity sufficient to permit protein microsequencing. The purification scheme of a novel germ cell-derived protein from GCCM designated GC-26 is presented along with several germ cell proteins using a combination of high pressure liquid chromatography (HPLC) columns. The purity of GC-26 and other germ cell proteins were confirmed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and silver staining. The identities of GC-26, a 26-kDa polypeptide, and other proteins were determined by direct protein microsequencing. These partial NH2-terminal amino acid sequences were compared with the existing databases at Protein Identification Resource (PIR), GenBank, and BLAST. These analyses revealed that these proteins are unique. This strategy should be useful for the micropurification of proteins from other biological samples and/or fluids.
Schetinger MR, Bonan CD, Frassetto SS
… +6 more, Wyse AT, Schierholt RC, Webber A, Dias RD, Sarkis JJ, Netto CA
Biochem Mol Biol Int
· 1999 Mar · PMID 10204084
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This study shows the effect of transient global cerebral ischemia (ISC) on hippocampal acetylcholinesterase (AChE) activity. Naive adult Wistar rats received either a brief (2 min) or a long (10 min) ischemic episode by...This study shows the effect of transient global cerebral ischemia (ISC) on hippocampal acetylcholinesterase (AChE) activity. Naive adult Wistar rats received either a brief (2 min) or a long (10 min) ischemic episode by the four-vessel occlusion method. Pre-conditioned rats received double ischemia: a 10 min episode inflicted 24 h after a 2 min event, a condition known to confer cytoprotection to CA1 pyramidal cells of hippocampus. 2 min of ischemia caused an increase in acetylcholinesterase activity both immediately and 30 min after the episode, however enzyme activity was significantly decreased after 24 h of reperfusion. 10 min of ischemia caused an increase in activity both 60 min and 24 h after ischemia. Conversely, pre-conditioned rats displayed lower activity both immediately and 60 min after ischemia. Our results suggest that: a) neuronal death, that follows 10 min of ischemia, is associated to a late increase in acetylcholinesterase activity; b) pre-conditioning is related to diminished acetylcholinesterase activity. This is in agreement with previous evidence that acetylcholinesterase inhibition and maintenance of acetylcholine levels are beneficial for cell surviving after cerebral ischemia.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204083
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Whether hsp90 acts in an ATP-dependent or independent way is of crucial importance for understanding the molecular mechanism of this chaperone and, to day, the involvement of ATP hydrolysis in hsp90 function is still a c...Whether hsp90 acts in an ATP-dependent or independent way is of crucial importance for understanding the molecular mechanism of this chaperone and, to day, the involvement of ATP hydrolysis in hsp90 function is still a controversial subject. ATPase activities may be detected in partially purified hsp90's preparations from rabbit muscle. We demonstrate that the major contaminant associated with hsp90 is the p97 fusion protein and that these oligomeric structures are copurifying together with the 20S proteasome and its PA28 activator. Improving the purification procedure permits to separate hsp90 and p97 to homogeneity. Then, our attempts failed to detect any significant ATPase activity in the hsp90 fraction. Thus, p97 would be principally responsible for the ATPase activity detected in partially purified hsp90 preparations from rabbit muscle.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204082
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A dipeptidyl peptidase (DPP) was purified to homogeneity using lys-ala-beta-naphthylamide, the standard substrate for DPP II. The enzyme is a monomer with a Mr of 70kDa, pl 5.2, and Km 5.0 microM. Its terminal amino acid...A dipeptidyl peptidase (DPP) was purified to homogeneity using lys-ala-beta-naphthylamide, the standard substrate for DPP II. The enzyme is a monomer with a Mr of 70kDa, pl 5.2, and Km 5.0 microM. Its terminal amino acid sequence was XXLLYAIQKRLF and was not identical to that of any known protein. Although initially considered to be a DPP II, the enzyme differed in some properties from classical DPP IIs. It had a pH optimum of 7.9, was not active on X-pro-naphthylamides, the usual substrates of mammalian DPP II, but was active on arg-arg- and asp-arg-naphthylamides, substrates acted on by the DPP III class of enzymes. This enzyme therefore combines properties typical of both DPP II and III and differs from all previously described DPPs. Activity on lys-ala-beta-naphthylamide was most abundant during aggregation and its activity is consistent with processing specific peptides during development.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204081
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Biofurcational theory of protein folding is developed describing the process of formation of protein native structure as a sequence of non-equilibrium irreversible fluctuations, specific for a particular protein. The mod...Biofurcational theory of protein folding is developed describing the process of formation of protein native structure as a sequence of non-equilibrium irreversible fluctuations, specific for a particular protein. The model gives explanation to all characteristic features of the folding process: stochastic mechanism, short time and precision of proteins self-assembling. A constructive role of entropy in the formation of a highly ordered structure out of disorder is discussed. A numerical method of a priori calculations of polypeptide structures basing on principles of bifractional folding model is presented.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204080
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The regulatory role of nitric oxide in capsaicin-induced 45Ca2+ accumulation in dorsal root ganglion neuronal cultures was investigated. Capsaicin-activated calcium entry was subject to complicated tuning by NO-releasing...The regulatory role of nitric oxide in capsaicin-induced 45Ca2+ accumulation in dorsal root ganglion neuronal cultures was investigated. Capsaicin-activated calcium entry was subject to complicated tuning by NO-releasing agents sodium nitroprusside, spermine/NO complex and NO synthase inhibitor NG-nitro-L-arginine methyl ester in concentration and stimulation protocol-dependent manner. In contrast, these agents failed to change depolarization-induced calcium influx. In experiments using dithiothreitol and 5,5-dithio-bis-2-nitrobenzoic acid this modulation was independent of the oxidizing action of NO. It is suggested that NO exerts a novel feedback modulatory effects on capsaicin-induced calcium entry into rat DRG neurons.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204079
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The rat p53 promoter has several potential transcription factor-recognition motifs. They include NF1-like, bHLH family, and AP1-like proteins binding sites. The binding protein to NF1-like motif was previously identified...The rat p53 promoter has several potential transcription factor-recognition motifs. They include NF1-like, bHLH family, and AP1-like proteins binding sites. The binding protein to NF1-like motif was previously identified. The protein has about 40kDa of molecular mass, which is smaller than that of NF1. Anti-NF1 polyclonal antibody does not recognize the protein. In this study, we isolated the 40kDa protein by sequence-specific DNA affinity chromatography. The isolated protein was assayed by DNase I footprinting analysis. To determine the transactivation effect of the protein, in vitro transcription with the purified 40kDa protein was carried out. After the addition of the purified 40kDa protein into the transcription reaction mixture, the transcription level of the p53 promoter was increased. This suggests that the 40 kDa NF1-like protein is a transcription activator for the rat p53 gene.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204078
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A cDNA clone, MT-c, encoding metalloprotease was isolated from snake (Agkistrodon halys brevicadus) venom gland cDNA library. Deduced amino acid sequence indicated that MT-c is composed of a signal sequence, amino-termin...A cDNA clone, MT-c, encoding metalloprotease was isolated from snake (Agkistrodon halys brevicadus) venom gland cDNA library. Deduced amino acid sequence indicated that MT-c is composed of a signal sequence, amino-terminal propeptide, a central metalloprotease domain, and a Lys-Gly-Asp (KGD) disintegrin domain. The partial cDNA encoding metalloprotease and disintegrin domain was subcloned and expressed in E. coli. The expressed MT-c protein was purified and successfully refolded into functional form retaining the enzyme activity. Analyses of the purified recombinant protease activity revealed that the enzyme hydrolyzes extracellular matrix proteins including type I gelatin, type IV and type V collagen, while type I, II, III collagens and fibronectin were insensitive to the proteolytic digestion. The recombinant enzyme was also able to degrade fibrinogen by specifically cleaving A alpha chain of the protein.
Hong M, Lee Y, Kim JW
… +5 more, Lim JS, Chang SY, Lee KS, Paik SG, Choe IS
Biochem Mol Biol Int
· 1999 Mar · PMID 10204077
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A cDNA clone encoding 10-formyltetrahydrofolate dehydrogenase (10-FTHFDH) was isolated from a human fetal liver cDNA library. It contained the open reading frame of 2,709 base pairs and predicted a protein comprising 902...A cDNA clone encoding 10-formyltetrahydrofolate dehydrogenase (10-FTHFDH) was isolated from a human fetal liver cDNA library. It contained the open reading frame of 2,709 base pairs and predicted a protein comprising 902 amino acids with a calculated molecular weight of 98,700 Da. The deduced protein showed about 93.6% homology (90.5% identity, 3.1% favored substitutions) when compared with rat 10-FTHFDH. The distribution of 10-FTHFDH transcript in various human tissues was studied by Northern blot analysis using poly(A+) RNAs from different tissues. The 10-FTHFDH transcript with an approximate size of 2.7 kb was mainly expressed in human kidney, skeletal muscle, and liver and rarely expressed in other tissues.
Chen C, Wei T, Gao Z
… +5 more, Zhao B, Hou J, Xu H, Xin W, Packer L
Biochem Mol Biol Int
· 1999 Mar · PMID 10204076
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The present study was conducted to evaluate the different effects of the constituents of EGb761 (Ginkgo biloba Extract) on apoptosis in cerebellar granule cells induced by hydroxyl radicals. The total flavonoid component...The present study was conducted to evaluate the different effects of the constituents of EGb761 (Ginkgo biloba Extract) on apoptosis in cerebellar granule cells induced by hydroxyl radicals. The total flavonoid component of EGb761, two pure EGb761 components (rutin and quercetin), and a mixture of flavonoids and terpenes protected cerebellar granule cells from oxidative damage and apoptosis induced by hydroxyl radicals. ESR(electron spin resonance) results showed that the IC50 of the flavonoids for scavenging hydroxyl radicals was almost the same as that of EGb761, even though flavonoids make up only 24% of EGb761, implying that other constituents of EGb761 besides flavonoids can scavenge hydroxyl radicals. Total terpenes of EGb761 did not protect against apoptosis. Flavonoids and terpenes did not show a synergistic effect in this regard. Terpenes did not scavenge hydroxyl radicals directly, which might be related to their "cage-like" structures.
Biochem Mol Biol Int
· 1999 Mar · PMID 10204075
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At the early stages of myogenesis, myoblasts fuse to form multinucleated myotubes. This morphological differentiation is the result of dynamic changes in gene regulation and expression. The ubiquitin proteasome-dependent...At the early stages of myogenesis, myoblasts fuse to form multinucleated myotubes. This morphological differentiation is the result of dynamic changes in gene regulation and expression. The ubiquitin proteasome-dependent pathway has been reported to play an important role in many aspects of cellular functions such as regulation of growth and cell cycle progression. In this study, we showed that the amount of mRNA's corresponding to the iota subunit of the 20S proteasome, the level of the S4 subunit of the 19S complex and the 20S and 26S proteasomes peptidase activities increased during myoblast fusion. Cell permeable 20S proteasome inhibitor prevented fusion with concomitant accumulation of ubiquitin-conjugated protein. On the other hand, inhibition of ubiquitin ligase E3 enzymes prevented the formation of ubiquitin conjugate and decreased the fusion process. These results strongly support the involvement of the ubiquitin-proteasome proteolytic pathway in the events leading to myoblast fusion.