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PubMedDate not supplied

Group graph of the genetic code.

The genetic code doublets can be divided into two octets of completely degenerate and ambiguous coding dinucleotides. These two octets have the algebraic property of lying on continuously connected planes on the group graph (a tesseract) of the Cartesian product of two Klein 4-groups of nucleotide exchange operators. The K X K group can also be broken into four cosets, one of which has completely degenerate coding elements, and another that has completely ambiguous coding elements. The two octets of coding doublets have the further algebraic property that the product of their internal exchange operators naturally divide into two exactly equivalent sets. These properties of the genetic code are relevant to unraveling error-detecting and error-correcting (proof-reading) aspects of the genetic code and may be helpful in understanding the context-sensitive grammar of genetic language.

Genetic Code↗
PubMedDate not supplied

Development of a polynucleotide vaccine from melanoma antigen recognized by T cells-1 and recombinant protein from melanoma antigen recognized by T cells-1 for melanoma vaccine clinical trials.

MART-1, a melanoma antigen recognized by T cells-1, is a melanocyte lineage-differentiation antigen expressed only in melanocytes and melanoma cells. This protein is recognized by many T-lymphocyte lines that are human leukocyte antigen (HLA)-A2 restricted and melanoma reactive. These observations have culminated in an array of clinical trials of MART-1 immunization using recombinant viruses or MART-1 immunodominant peptides. Polynucleotide immunization is a promising alternative to recombinant viral vaccines that allows delivery of the full-length cDNA encoding all potential peptide epitopes in a vector that is uncompromised by anti-viral immunity. In preparation for a phase I clinical trial of MART-1 polynucleotide immunization in patients with resected melanoma who were at significant risk for recurrence, the authors constructed a plasmid DNA encoding the MART-1 cDNA under transcriptional regulatory control of the cytomegalovirus immediate early promoter-enhancer and partially deleted intron A. This plasmid directs high-level MART-1 expression in transduced myoblasts and maturing myocytes diffusely throughout the cytoplasm. Immunization of mice with this construct by intramuscular injection elicited MART-1-specific immune responses in all animals. Previous trials of MART-1 immunization have been unable to examine the humoral immune response to MART-1 because of a lack of sufficient, highly purified protein. We have produced and purified Escherichia coli recombinant MART-1 protein using a glutathione-S-transferase fusion protein expression system. Protein staining of a sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a band of MART-1 protein at approximately 20 kD; and Western immunoblotting with an anti-MART-1 monoclonal antibody confirmed a doublet at approximately 20 kD. These findings are consistent with previous reports using different expression systems for recombinant MART-1. This protein preparation functioned well in enzyme-linked immunosorbent assays (ELISAs) to detect anti-MART-1 antibody responses in a mouse model; and a panel of healthy donor human sera showed minimal binding to ELISA plates coated with the protein, supporting its utility in monitoring human anti-MART-1 antibody responses. The glutathione-S-transferase fusion method yielded approximately 200 micrograms MART-1 per 2-L bacterial culture, enough to coat 100 ELISA plates.

Animals↗
PubMed2000

Pathological tau phenotypes. The weight of mutations, polymorphisms, and differential neuronal vulnerabilities.

In tauopathies, comparative biochemistry of tau aggregates shows that they differ in both phosphorylation and content of tau isoforms. Six tau isoforms are found in human brain that contain either three (3R) or four microtubule-binding domains (4R). In Alzheimer's disease, all six of the tau isoforms are phosphorylated and aggregate into paired helical filaments. They are detected by immunoblotting as a major tau triplet (tau 55, 64, and 69). In corticobasal degeneration and progressive supranuclear palsy, only phosphorylated 4R-tau isoforms aggregate and appear as a major tau doublet (tau 64 and 69). In Pick's disease, only phosphorylated 3R-tau isoforms aggregate into filaments and are characterized by another major tau doublet (tau 55 and 64). Finally, recent findings provide a direct link between a genetic defect in tau and its abnormal aggregation into filaments in frontotemporal dementia with parkinsonism linked to chromosome 17. In the present study, the question of a relationship between tau isoforms and cell morphology is raised. To answer this question, stably transfected human neuroblastoma SY5Y cell lines with either 3R- or 4R-tau isoforms are established. Cell morphology and tau phosphorylation were modified, suggesting that cells undergo profound changes in their metabolism and viability.

Alzheimer Disease↗
PubMed2000

Changes in protein kinase C epsilon phosphorylation status and intracellular localization as 3T3 and 3T6 fibroblasts grow to confluency and quiescence: a role for phosphorylation at ser-729?

Protein kinase C (PKC) epsilon in 3T3 and 3T6 fibroblasts and in C6 glioma cells migrated on SDS/PAGE predominantly as a doublet with molecular masses of 87 and 95 kDa (PKC epsilon(87) and PKC epsilon(95) respectively). PKC epsilon(95) predominates when cells reach confluency but PKC epsilon(87) was the main form detected within 15 min when confluent cells were passaged at low cell density into fresh medium containing serum and allowed to adhere. Matrix-assisted laser-desorption ionization-time-of-flight MS analysis and experiments with phosphospecific antibodies revealed that PKC epsilon(87) is phosphorylated at Thr-566 and Ser-703, and PKC epsilon(95) is additionally phosphorylated at Ser-729. Cell fractionation studies revealed that PKC epsilon(95) is associated with the nuclear fraction, whereas PKC epsilon(87) was found in the 100,000 g cytosol fraction. Immunofluorescence studies confirmed these findings and showed that PKC epsilon(95) had a perinuclear, probably Golgi, localization and PKC epsilon(87) was distributed in the cytosol. It is proposed that phosphorylation at Ser-729 may be important for determining the intracellular localization of PKC epsilon, and that a specific Ser-729 phosphatase may be activated on cell passage to convert PKC epsilon(95) to PKC epsilon(87).

3T3 Cells↗
PubMed2004

Steric asymmetry and lambda-doublet propensities in state-to-state rotationally inelastic scattering of NO(2Pi(1/2)) with He.

Relative integrated cross sections are measured for rotationally inelastic scattering of NO(2Pi(1/2)),hexapole selected in the upper lambda-doublet level of the ground rotational state (j = 0.5), in collisions with He at a nominal energy of 514 cm(-1). Application of a static electric field E in the scattering region, directed parallel or antiparallel to the relative velocity vector v, allows the state-selected NO molecule to be oriented with either the N end or the O end towards the incoming He atom. Laser-induced fluorescence detection of the final state of the NO molecule is used to determine the experimental steric asymmetry, [formula: see text], which is equal to within a factor of (- 1) to the molecular steric effect, S(i-->f) is identical with (sigma(He-->NO) - (sigma(He-->ON))/(sigma(He-->NO) + sigma(He-->ON)). The dependence of the integral inelastic cross section on the incoming lambda-doublet component is also observed as a function of the final rotational (j'), spin-orbit (omega'), and lambda-doublet (epsilon') state. The measured steric asymmetries are significantly larger than previously observed for NO-Ar scattering, supporting earlier proposals that the repulsive part of the interaction potential is responsible for the steric asymmetry. In contrast to the case of scattering with Ar, the steric asymmetry of NO-He collisions is not very sensitive to the value of omega'. However, the lambda-doublet propensities are very different for [omega=0.5(F1)-->omega'= 1.5(F2)] and [omega=0.5(F1)-->omega'=0.5(F1)] transitions. Spin-orbit manifold conserving collisions exhibit a propensity for parity conservation at low deltaj, but spin-orbit manifold changing collisions do not show this propensity. In conjunction with the experiments, state-to-state cross sections for scattering of oriented NO(2Pi) molecules with He atoms are predicted from close-coupling calculations on restricted coupled-cluster methods including single, double, and noniterated triple excitations [J. Klos, G. Chalasinski, M. T. Berry, R.Bukowski, and S. M. Cybulski, J. Chem. Phys. 112, 2195 (2000)] and correlated electron-pair approximation [M. Yang and M. H. Alexander, J. Chem. Phys. 103, 6973 (1995)] potential energy surfaces. The calculated steric asymmetry S(i-->f) of the inelastic cross sections at Etr= 514 cm(-1) is in reasonable agreement with that derived from the present experimental measurements for both spin-manifold conserving (F1-->Fl) and spin-manifold changing (F1 --F2) collisions, except that the overall sign of the effect is opposite. Additionally, calculated field-free integral cross sections for collisions at Etr = 508 cm(-1) are compared to the experimental data of Joswig et al. [J. Chem. Phys.85, 1904 (1986)]. Finally, the calculated differential cross section for collision energy Etr= 491 cm(-1) is compared to experimental data of Westley et al. [J. Chem. Phys. 114, 2669 (2001)] for the spin-orbit conserving transition F1 (j = 0.5) -F1f (j' = 3.5).

Journal Article↗
PubMed1986

Monoclonal antibodies distinguish titins from heart and skeletal muscle.

Murine monoclonal antibodies specific for titin have been elicited using a chicken heart muscle residue as antigen. The three antibodies T1, T3, and T4 recognize both bands of the titin doublet in immunoblot analysis on polypeptides from chicken breast muscle. In contrast, on chicken cardiac myofibrils two of the antibodies (T1, T4) react only with the upper band of the doublet indicating immunological differences between heart and skeletal muscle titin. This difference is even more pronounced for rat and mouse. Although all three antibodies react with skeletal muscle titin, T1 and T4 did not detect heart titin, whereas T3 reacts with this titin both in immunofluorescence microscopy and in immunoblots. Immunofluorescence microscopy of myofibrils and frozen tissues from a variety of vertebrates extends these results and shows that the three antibodies recognize different epitopes. All three titin antibodies decorate at the A-I junction of the myofibrils freshly prepared from chicken skeletal muscle and immunoelectron microscopy using native myosin filaments demonstrates that titin is present at the ends of the thick filaments. In chicken heart, however, antibodies T1 and T4 stain within the I-band rather than at the A-I junction. The three antibodies did not react with any of the nonmuscle tissues or permanent cell lines tested and do not decorate smooth muscle. In primary cultures of embryonic chicken skeletal muscle cells titin first appears as longitudinal striations in mononucleated myoblasts and later at the myofibrillar A-I junction of the myotubes.

Animals↗
PubMed1997

Comparative study of uterine morphogenesis and protein secretion in neonatal White crossbred and Meishan gilts.

Thirty-five crossbred and 22 Meishan contemporary gilts were necropsied on Day 1, 14, 28, 42, or 56 of age (birth = Day 0). At necropsy, a cross section of one uterine horn was fixed for histomorphometric study, and minced uterine tissue was cultured with 50 muCi [3H]leucine. Secreted proteins were identified by two-dimensional PAGE, fluorography, and incorporation of radioactivity. Body weights at necropsy were similar for the two breeds and increased (p < 0.01) between Days 1 and 56 of age. Ovarian and uterine weights, as well as histomorphometric areas, were similar for the two breeds on Day 1 but increased markedly (p < 0.01) in Meishan gilts on Day 56. In gilts of both breeds, secretion of uterine proteins 1 (M(r) x 10(-3)/pI; 45/6.0), 2a and 2b (doublet, 25/6.2), and 3 (20/5.5) increased in association with endometrial gland development. A fourth protein (97/4.0) was observed in gilts of both breeds but was more abundant in Meishan; a fifth protein (13/6.0) was detected only in crossbred gilts on Day 56. Although specific regulatory roles for locally produced uterine proteins remain to be defined, the increase in specific uterine proteins and breed differences in uterine protein secretion suggest that uterine proteins may influence early uterine development.

Age Factors↗
PubMed1990

The heterogeneity of porcine 32,000 Mr inhibin alpha-subunit: a gel electrophoresis and immunoblot study.

Porcine 32,000 Mr inhibin is a glycoprotein with one asparagine-linked glycosylation site on the alpha-subunit. The presence of carbohydrate on the alpha-subunit was visualized by periodate-Schiff (PAS) staining. This stain for carbohydrate also verified that the beta-subunit of 32,000 Mr porcine inhibin does not contain carbohydrate. When analyzed by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1D-PAGE) under reducing conditions, the inhibin alpha-subunit consistently existed as a doublet, and by the PAS stain, both bands of the doublet were glycosylated. Analysis by two-dimensional (2D) PAGE further revealed the presence of charge isoforms of the alpha-subunit. The alpha-subunit of inhibin could be deglycosylated by N-glycanase, but not by endoglycosidase F, endoglycosidase D, or endoglycosidase H. When the N-glycanase-treated inhibin was analyzed by either 1D-PAGE or 2D-PAGE, the molecular size of the alpha-subunit was reduced by 3500 Mr. Each doublet band observed with reducing conditions in 1D-PAGE or 2D-PAGE for the alpha-subunit became a single band (spot) in the deglycosylated alpha-subunit. However, the charge heterogeneity detected by 2D-PAGE was retained, indicating that only a portion of this heterogeneity is attributable to the carbohydrate moiety. The in vitro biological activity of the deglycosylated inhibin was not different from the control sample. The composition of the carbohydrate in inhibin was investigated with the Dionex carbohydrate analyzer. Inhibin contains fucose, glucosamine, galactose, mannose, and glucose. Colorimetric analysis revealed the presence of sialic acid. Taken together, this implies some aspect of the peptide portion of the molecule is involved in charge heterogeneity. Inhibin may have an unusual carbohydrate component, as evidenced by the detection of glucose in inhibin samples. The absence of glucose in the carbohydrate moiety of another glycoprotein fraction that accompanied the inhibin through all the same fractionation procedures argues against the artifactual introduction of glucose in the fractionation medium per se.

Amidohydrolases↗
PubMed2006

Vibrational spectroscopic studies and density functional theory calculations of speciation in the CO2-water system.

Raman spectra of CO(2) dissolved in water and heavy water were measured at 22 degrees C, and the Fermi doublet of CO(2), normally at 1285.45 and 1388.15 cm(-1) in the gaseous state, revealed differences in normal water and heavy water, although no symmetry lowering of the hydrated CO(2) could be detected. Raman spectra of crystalline KHCO(3) and KDCO(3) were measured at 22 degrees C and compared with the infrared data from the literature. In these solids, (H(D)CO(3))(2)(2-) dimers exist and the spectra reveal strong intramolecular coupling. The vibrational data of the dimer (C(2h) symmetry) were compared with the values from density functional theory (DFT) calculations and the agreement is fair. Careful measurements were made of the Raman spectra of aqueous KHCO(3), and KDCO(3) solutions in D(2)O down to 50 cm(-1) and, in some cases, down to very low concentrations (> or =0.0026 mol/kg). In order to complement the spectroscopic assignments, infrared solution spectra were also measured. The vibrational spectra of HCO(3)(-)(aq) and DCO(3)(-)(D(2)O) were assigned, and the measured data compared well with data derived from DFT calculations. The symmetry for HCO(3)(-)(aq) is C(1), while the gas-phase structure of HCO(3)(-) possesses Cs symmetry. No dimers could be found in aqueous solutions, but at the highest KHCO(3) concentration (3.270 mol/kg) intermolecular coupling between HCO(3)(-)(aq) anions could be detected. KHCO(3) solutions do not dissolve congruently, and with increasing concentrations of the salt increasing amounts of carbonate could be detected. Raman and infrared spectra of aqueous Na(2) -, K(2) -, and Cs(2)CO(3) solutions in water and heavy water were measured down to 50 cm(-1) and in some cases down to extremely low concentrations (0.002 mol/kg) and up to the saturation state. For carbonate in aqueous solution a symmetry breaking of the D(3h) symmetry could be detected similar to the situation in aqueous nitrate solutions. Strong hydration of carbonate in aqueous solution could be detected by Raman spectroscopy. The hydrogen bonds between carbonate in heavy water are stronger than the ones in normal water. In sodium and potassium carbonate solutions no contact ion pairs could be detected even up to the saturated solutions. However, solvent separated ion pairs were inferred in concentrated solutions in accordance with recent dielectric relaxation spectroscopy (DRS) measurements. Quantitative Raman measurements of the hydrolysis of carbonate in aqueous K(2)CO(3) solutions were carried out and the hydrolysis degree a was determined as a function of concentration at 22 degrees C. The second dissociation constant, pK(2), of the carbonic acid was determined to be equal to 10.38 at 22 degrees C.

Algorithms↗
PubMed2000

Lactate editing and lipid suppression by continuous wavelet transform analysis: application to simulated and (1)H MRS brain tumor time-domain data.

Determination of lactate concentrations in vivo is required in the noninvasive diagnosis, staging, and therapeutic monitoring of diseases such as cancer, heart disease, and stroke. An iterative filtering process based on the continuous wavelet transform (CWT) method in the time domain is proposed to isolate the lactate doublet signal from overlapping lipid resonances and estimate the magnetic resonance spectroscopy (MRS) parameters of the lactate methyl signal (signal amplitude, chemical shift, J-coupling and apparent transverse relaxation time (T*(2))). This method offers a number of advantages over the multiple quantum (MQ) and difference spectroscopy approaches, including: 1) full recovery of the lactate methyl signal, whereas the MQ methods usually detect 50% of the signal intensity; 2) in contrast to MQ methods, the lipid signal is retained together with J-coupling data on the lactate peak; 3) the CWT method is much less sensitive to motion artifacts than difference spectroscopy. Application of the method to simulated and real (1)H MRS data collected from human blood plasma and brain tumors demonstrated that this filter provides accurate estimates of the MRS parameters of the lactate doublet and efficiently removes lipid contributions.

Adult↗
PubMed1997

Detection of p53 point mutations by double-gradient, denaturing gradient gel electrophoresis.

Genetic instability is a typical feature of tumor cells. This evidence has stimulated the development of rapid methods for detection of gene mutations. A new, improved protocol for denaturing gradient gel electrophoresis (DGGE), to screen for point mutations in genomic DNA, is reported: double gradient (DG) DGGE. In this technique, to the primary, denaturing gradient (typically 30-80% or 40-80% urea/formamide) a secondary gradient, colinear with the first, is superimposed: a porosity gradient (typically 6.5-12% polyacrylamide). The secondary gradient acts by recompacting smeared and diffuse bands of heteroduplexes, which are often indistinguishable from background fluorescence, and by augmenting the resolution between closely spaced homoduplex zones. This allows proper densitometric quantitation of the ratio of the two homoduplex bands. The reliability of this technique has been documented by detection of a number of mutations in exons 6 and 8 of the p53 gene which had escaped revelation by single-strand conformational polymorphism (SSCP) analysis. Additionally, the precise assessment of ratio of the doublet of homoduplex bands has allowed quantitation of the extent of p53 mutation in a mixed cell population extracted from a tumor specimen.

Electrophoresis, Polyacrylamide Gel↗
PubMed1994

Generation of a monoclonal antibody against the myelin protein CNP (2',3'-cyclic nucleotide 3'-phosphodiesterase) suitable for biochemical and for immunohistochemical investigations of CNP.

The functional role of CNP (2',3'-cyclic nucleotide 3'-phosphodiesterase), a minor component of central and peripheral myelin is still unclear. Here we describe preparation of a monoclonal antibody directed against CNP. The antibody, of the immunoglobulin IgG1 type, raised with a basic 46 kDa membrane-associated protein solubilized from pig cerebellar membranes, can be used to detect immunoreactivity in solubilized brain homogenates from pig, mouse, rat, sheep, cow and man, in cerebrum and cerebellum, but not in other tissues such as liver, skeletal and heart muscle. The antibody recognizes the CNP doublet band and shows no cross-reactivity with any of the other brain proteins solubilized. In tissue sections from paraformaldehyde-fixed rat brain the antigen was localized in oligodendrocytes. In cultured glial cells from newborn mice the antibody stained cells which were identified as oligodendrocytes by co-localization of myelin basic protein. Even cells from a C6 rat glioma cell line, which contain very little of CNP, were labeled by the monoclonal antibody. Thus the monoclonal antibody recognizing CNP from several species is suitable for immunocytochemical investigations and also for biochemical studies of CNP, since the antibody has been employed for immunoprecipitation and immunopurification of CNP in crude brain homogenates.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1998

Heterogeneity and subunit composition of the haemoglobins of five tilapiine species (Teleostei, Cichlidae) of the genera Oreochromis and Sarotherodon.

Haemoglobins of five tilapiine species of the genera Oreochromis and Sarotherodon were investigated. By gel filtration chromatography a molecular weight of 67-69 kDa was determined for the tetrameric molecules which remained stable between pH 5.0 and pH 9.1. When subjected to sodium dodecyl sulphate-Ureapolyacrylamide gel electrophoresis (PAGE), haemoglobins of all species each were split into monomers of three different molecular weights ranging between 16.3 kDA and 17.6 kDa. Subsequently, isoelectric focusing separated haemolysates into about 23 differently charged tetrameric haemoglobins that were arranged in species-specific patterns. This diversity was shown to result from the occurrence of different types of globin chains. By acidic urea PAGE a total of seven major alpha-globins and five major beta-globins were detected and species-characteristic chain variants were identified. To determine the globin chain composition of particular haemoglobin tetramers, 26 bands were isolated by isoelectric focusing and analysed by acidic urea PAGE. Tetramers consisted of doublets of identical alpha- and identical beta-chains (alpha 2 beta 2, symmetric tetramers), or combinations of three (alpha 2 beta beta *; alpha alpha * beta 2) or four (alpha alpha * beta beta *) distinct chains (asymmetric tetramers). Finally, globin chains of Oreochromis niloticus were subjected to partial N-terminal amino acid sequencing. Differences in the composition of the three major beta-chains could be shown, whereas the alpha-chains were N-terminally blocked.

Amino Acid Sequence↗
PubMed1992

Direct detection of circulating free radicals in the rat using electron spin resonance spectrometry.

We developed a new technique for directly observing in vivo free radical formation in the circulating blood of living rats using electron spin resonance (ESR) spectrometry without any labeling or trapping agents. It was found that a doublet peak spectrum was obtained following ferric citrate and ascorbic acid injection. The signals were confirmed in different ways to be due to ascorbic acid radicals. These results provide evidence to support the involvement of free radical intermediates in iron-ascorbic acid reactions, and further confirm the suggested mechanisms of both the adverse and protective effects of ascorbic acid in biological systems. Furthermore, this method of direct observation is a new application of ESR spectrometry to living animals.

Animals↗
PubMed1998

Heteronuclear correlation experiments for the determination of one-bond coupling constants.

Spin-state selective experiments, HSQC-alpha/beta and CT-HMQC-alpha/beta, are proposed for the simple and rapid measurement of scalar one-bond coupling constants in two-dimensional, 1H-detected 15N-1H or 13C-1H correlation experiments based on HSQC and HMQC schemes. Pairs of subspectra are obtained, containing either the high-field or the low-field component of the doublet representing the one-bond coupling constant. The subspectral editing procedure retains the full sensitivity of HSQC and HMQC spectra recorded without heteronuclear decoupling during data acquisition, with a spectral resolution similar to that of decoupled spectra.

Bacterial Proteins↗
PubMed1999

Studies of organic residues from ancient Egyptian mummies using high temperature-gas chromatography-mass spectrometry and sequential thermal desorption-gas chromatography-mass spectrometry and pyrolysis-gas chromatography-mass spectrometry.

The techniques of gas chromatography-mass spectrometry (GC-MS) and sequential thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) have been utilised to characterise the constituents of tissue-derived or applied organic material from two Pharaonic Egyptian mummies with a view to identifying embalming practices/substances. The results obtained using TD-GC-MS revealed a series of monocarboxylic acids with the C16:0, C18:1 and C18:0 components dominating in both mummies. The thermal desorption products related to cholesterol, i.e., cholesta-3,5,7-triene and cholesta-3,5-diene (only in Khnum Nakht), were detected in both mummies. Khnum Nakht also contained a number of straight chain alkyl amides (C16-C18) and an alkyl nitrile (C18). Other products included the 2,5-diketopiperazine derivative (DKP) of proline-glycine (pro-gly) which was a major component (7.9%) in Khnum Nakht but only a very minor component in Horemkenesi. Py-GC-MS of samples of both specimens yielded a series of alkene/alkane doublets (Horemkenesi C6-C18, Khnum Nakht C6-C24) which dominated their chromatograms. Series of methyl ketones in the C9-C19 chain length range were also present, with C5-C7 cyclic ketones occurring in Horemkenesi only. These ketones are indicative of covalent bond cleavage, probably of polymerised acyl lipids. Nitrogenous products included nitriles (C9-C18) which were significant in both samples, and amides which were only detected in Khnum Nakht. Also present amongst the pyrolysis products were three steroidal hydrocarbons, cholest-(?)-ene, cholesta-3,5,7-triene and cholesta-3,5-diene. High temperature-GC-MS of trimethylsilylated lipid extracts yielded similar monocarboxylic acids to that obtained using TD-GC-MS, while a series of alpha, omega-dicarboxylic acids and a number of mono- and di-hydroxy carboxylic acids not seen in the thermal desorption or pyrolysis GC-MS analyses were significant constituents in both mummy samples. Overall, the use of GC-MS and sequential TD-GC-MS and Py-GC-MS has demonstrated in both mummies the presence of a complex suite of lipids and proteinaceous components whose compositions indicates extensive alteration via oxidative and hydrolytic processes during long-term interment. None of the classical embalming resins was detected but an exogenous origin for at least a proportion of these components cannot be discounted since fats, oils and gelatin have been proposed as embalming agents in mummification. The combined approach of sequential TD- and Py-GC-MS has potential for application to the characterisation of embalming materials in mummies. Most importantly these techniques virtually eliminate any destruction of the mummified bodies thereby allowing the scope of investigations of ancient Egyptian funerary practices to be significantly extended.

Embalming↗
PubMed1995

Middle-range clustering of nucleotides in genomes.

We propose a novel, transparent and very simple algorithm to analyze middle-range correlations in genomic nucleotide sequences. Analysis by this algorithm of the EMBL Nucleotide Sequence Database demonstrates that all four nucleotides cluster in the genomic nucleotide sequences of eukaryotes on the scale of several hundred base pairs. In prokaryotes, the clustering is weak but still evident. The non-dominant three bases are deficient in the clusters, while A is the most deficient nucleotide in the clusters of C, and vice versa, and G is the most deficient nucleotide in the clusters of T, and vice versa. The algorithm also detects CG islands, extending over 1 kb, in vertebrate sequences. In plants, the CG islands are shown to be much smaller, if they exist at all. A clustering tendency is also exhibited by the TA doublet. Other doublets do not cluster. We observe no strong correlation between nucleotides separated in genomes by > 1 kb.

Algorithms↗
PubMed1979

An iron-containing superoxide dismutase from Anacystis nidulans.

Superoxide dismutase (SOD) was isolated and purified from Anacystis nidulans to near electrophoretic homogeneity. The enzyme has a molecular weight of 37,500, as determined by gel filtration and SDS-gel electrophoresis. The enzyme molecule consists of two subunits of identical molecular weight. Proton-induced X-ray elemental analysis (PIXE) showed that the SOD of A. nidulans is an iron-containing enzyme; the Fe:enzyme mol ratio was found to be 1. The EPR spectra indicated that the active center contains high-spin ferric ion. Based on quantitative EPR data, we conclude that eseentially all iron ions were detected in the EPR experiments and were present in the Fe3+ active center. Effective g'-values were calculated from computer-simulated spectra and analysis of the g'-value anisotropy of the +/-3/2 Kramers doublet made the calculation of crystal field parameters possible. The symmetry of the Fe3+ ion in the SOD molecule was found to be close to rhombic (E/D=0.240).

Binding Sites↗