bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative 1H NMR analysis of alkaline polysulfide solutions
Authors: Argyropoulos Dimitris S. , Hou Yihua , Ganesaratnam Ramana , Harpp David N. , Koda Keiichi
Published: February 2005

A novel analytical protocol for the absolute determination of the various polysulfide species present in alkaline aqueous media was developed. The method is comprised of alkylating polysulfide ions with dimethyl sulfate, followed by quantitative proton NMR spectroscopy using 1,3,5-tributyl benzene as the internal standard. In order to arrive at a quantitative acquisition protocol, a number of variables were examined in detail for their effect on the alkylation reaction, including the presence of oxygen, the amount of dimethyl sulfate and sodium hydroxide, and the various modes of adding the alkylating reagent to the reaction mixture. Most of these variables were found to play a role in determining the quantitative reliability of the procedure. Consequently, a method is described that can be used for the efficient and reliable quantitative detection of polysulfide ions. The protocol developed could be particularly useful in promoting our understanding of the intricate and delicate chemistry of polysulfide equilibria in aqueous alkaline media.
The carbonate radical as one-electron oxidant of carbohydrates in alkaline media
Authors: Carlsson Magnus , Stenman David , Merényi Gábor , Reitberger Torbjörn
Published: February 2005

The mechanism by which the carbonate radical anion reacts with D-glucose in alkaline aqueous solutions has been studied by means of γ-radiolysis. From the product analysis it is concluded that the reaction sequence is initiated by a one-electron transfer between the carbonate radical anion and deprotonated D-glucose. In the presence of molecular oxygen, the major, if not only products of this reaction sequence are formic acid, arabinose and gluconic acid and reaction schemes are proposed to account for the observed formation of these products.
Properties of chemically and mechanically isolated fibres of spruce (Picea abies [L.] Karst.). Part 1: Structural and chemical characterisation
Authors: Burgert Ingo , Gierlinger Notburga , Zimmermann Tanja
Published: February 2005

Single fibres of spruce (Picea abies [L.] Karst.) were isolated both chemically and mechanically from a solid wood sample. Mechanical isolation was carried out using very fine tweezers to peel out fibres, thereby taking advantage of the low shear strength between them. Chemical isolation was achieved using hydrogen peroxide and glacial acetic acid. Fibres were examined with Fourier-transform infrared (FT-IR) microscopy, and field-emission environmental scanning electron microscopy (FE-ESEM) in low-Vacuum mode to compare the isolation techniques with respect to their influence on cell wall structure and polymer assembly. The chemical treatment led to degradation of lignin and hemicelluloses, significantly influencing the cell wall assembly and structure. The cell wall polymers of mechanically isolated fibres remained in their natural constitution. As expected, the peeling process caused separation of cell wall layers. Our examinations indicate that delamination predominately took place at the interface between the secondary cell wall and the compound middle lamella. However, fracture between the S1 and S2 layers was examined as well. With respect to fibre quality, it was of particular importance that transverse crack propagation in the secondary cell walls (S2) was not observed.
Electrochemical redox reactions of uranium(VI) complexes with multidentate ligands in dimethyl sulfoxide
Authors: Kim Seong-Yun , Asakura Toshihide , Morita Yasuji , Uchiyama Gunzo , Ikeda Yasuhisa
Published: February 2005

Electrochemical reactions of UO2(β-diketonato)2-dmso, UO2(trop)2dmso, UO2(sap)(dmso)2, and UO2(salen)dmso (dmso = dimethyl sulfoxide, β-diketonate = benzoylacetonate (ba), benzoyltrifluoroacetonate (btfa), and thenoyltrifluoroacetonate (ttfa), trop = tropolonate, sap = 2-salicylidenaminophenolate, and salen = N , N´-disalicylidenethylenediaminate) complexes in dmso solutions containing tetrabutylammonium perchlorate as a supporting electrolyte have been studied with cyclic voltammetry. These uranyl(VI) complexes were found to be reduced quasi -reversibly to U(V) species. The formal redox potentials (E°, vs . ferrocen/ferrocenium) for U(VI)/U(V) couples were determined to be -1.416 V for UO2(ba)2dmso, -1.073 V for UO2(btfa)2dmso, -1.082 V for UO2(ttfa)2dmso, -1.379 V for UO2(trop)2dmso, -1.500 V for UO2(sap)(dmso)2, and -1.602 V for UO2(salen)dmso. Furthermore, the resulting U(V) complexes, [UO2(btfa)2dmso]-, [UO2(ttfa)2dmso]-, and [UO2(salen)dmso]-, were found to be able to exist stably in dmso solutions.
A Sociological Account of the Persistence of Invalidated Anorexic Identities
Authors: Haworth‐Hoeppner Susan , Maines David
Published: February 2005

Most versions of identity theory have had difficulty explaining the persistence of invalidated identities. Drawing from data on anorexic identity transactions, we identify three dimensions that contribute to understanding this persistence. Two dimensions, size and control, are shown to be the locus of identity invalidation; the third, desirability, is shown to be the locus of validation. Confirmation of one's sense of being desirable, we propose, contributes to anorexics continuing to appropriate identities invalidated by others. We argue that the concepts “master identity,” “fictionalized identity,” and what we term “discordant awareness context” are more useful for theorizing the persistence of invalidated identities, such as anorexia, than those focusing on the degree of consensus over the person as a social object found in conventional identity theory.
“How Edge Are You?” Constructing Authentic Identities and Subcultural Boundaries in a Straightedge Internet Forum
Authors: Williams J. Patrick , Copes Heith
Published: February 2005

We analyze how participants in an internet forum dedicated to the straightedge subculture articulate and express subcultural identities and boundaries, with particular attention to how they accomplish these tasks in a computer‐mediated context. Through participant observation, “focused discussions,” and interviews, we explore the complexity of identity‐making processes in terms of cyberspace and subculture, conceptualizing identification as occurring at the intersection of biography, subculture, and technology. We find that the internet influences how individuals participate in subcultural communities by analyzing their claims for authenticity and how they position themselves in relation to subcultural boundaries. This article provides insight into the dialectic relationship between participation in a subculture and in an internet community.
An Expectation-Maximization–Likelihood-Ratio Test for Handling Missing Data
Authors: Niu Tianhua , Ding Adam A , Kreutz Reinhold , Lindpaintner Klaus
Published: February 2005

The mapping of quantitative trait loci (QTL) is an important research question in animal and human studies. Missing data are common in such study settings, and ignoring such missing data may result in biased estimates of the genotypic effect and thus may eventually lead to errant results and incorrect inferences. In this article, we developed an expectation-maximization (EM)–likelihood-ratio test (LRT) in QTL mapping. Simulation studies based on two different types of phylogenetic models revealed that the EM-LRT, a statistical technique that uses EM-based parameter estimates in the presence of missing data, offers a greater statistical power compared with the ordinary analysis-of-variance (ANOVA)-based test, which discards incomplete data. We applied both the EM-LRT and the ANOVA-based test in a real data set collected from F2 intercross studies of inbred mouse strains. It was found that the EM-LRT makes an optimal use of the observed data and its advantages over the ANOVA F-test are more pronounced when more missing data are present. The EM-LRT method may have important implications in QTL mapping in experimental crosses.
Successful Implementation of Genetic Education for Native Americans Workshops at National Conferences
Authors: Dignan Mark B , Burhansstipanov Linda , Bemis Lynne
Published: February 2005

Genetic Education for Native Americans (GENA) was a National Human Genome Research Institute (NHGRI)/Ethical, Legal, and Social Implications (ELSI)-funded educational intervention designed to provide a unique genetics education program for Native American college and university students. A curriculum was developed and implemented in workshops in geographically diverse settings throughout the United States, primarily in conjunction with regional and national scientific conferences that include substantial numbers of Native American attendees. The original curriculum includes 24 objectives and has been offered in two formats, as a 16-hr “comprehensive” program and in briefer workshops (referred to as “customized” hereafter) that are designed to include objectives for selected audiences. Both formats teach sufficient genetics to allow discussion and understanding of the ELSI and cultural issues related to genetics science. This article describes the evaluation findings from our implementation of both formats of the GENA curriculum.
Adsorption from aqueous solution based on the synergism between hydrogen bonding and hydrophobic interactions
Authors: Li Jia Zheng , Yao Kang De
Published: February 2005

The adsorption of aniline, N‐methyl aniline, and N,N‐dimethyl aniline on carboxyl resin(D152) in different media, water, ethanol, and hexane have been studied. In water the adsorption affinity of three sorbates on D152 increased with an increasing number of methyl groups on N atoms, which indicated that the adsorption of the three sorbates on D152 was driven by a hydrophobic interaction. But the adsorption enthalpy of the three sorbates exceeded the van der Waals force and was in the range of hydrogen bonding interactions, which indicated that the hydrogen bonding also played an important role. In hexane the adsorption affinity decreased with the increasing number of methyl groups on the N atom, presenting the reverse order to that in water. This fact revealed that the hydrogen bonding played a predominant role for the adsorption in hexane. In ethanol, there was no adsorption of three sorbates on D152 resin, because both the van der Waals force and the hydrogen bonding interaction between the resin and sorbate were depressed. The hydrogen bonding between resin and sorbates in water was also depressed, but the hydrogen bonding adsorption remained. This result suggested that there might be a synergetic effect between the van der Waals and hydrogen bonding interactions in the adsorption of sorbate on D152 resin in water. The synergetic effect was explained thermodynamically. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 841–845, 2005
Synergistic effect of phosphorus, nitrogen, and silicon on flame‐retardant properties and char yield in polypropylene
Authors: Li Qiang , Jiang Pingkai , Su Zhanpai , Wei Ping , Wang Genglin , Tang Xiaozhen
Published: February 2005

In this study, several flame retardants (FRs), containing phosphorus, nitrogen, and silicon, were synthesized. These synthesized FRs were blended with polypropylene (PP) to obtain mixture samples. The flame‐retardant properties of these mixture samples were estimated by the limiting oxygen index (LOI) value and thermal stabilities were characterized by thermogravimetric analysis. The LOI values of these samples were improved from 17.0 to 26.0 and the char yield increased from 0 to 27 wt %. A comparison of these samples, with respect to their LOI values and carbon yield, showed that the FRs, which simultaneously contained phosphorus, nitrogen, and silicon elements, can provide materials with the best flame‐retardant properties, suggesting that there is a synergistic effect among the three elements on the flame‐retardant properties and char yield when they are used in PP. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 854–860, 2005
Molecular architectures of four‐arm star‐shaped styrene‐butadiene copolymer
Authors: Zhang Lina , Ma Zhaocheng , Xiong Xiaopeng , Xu Xiaojuan , Ma Rui , Li Yang
Published: February 2005

To understand the molecular architectures of styrene‐butadiene four‐arm star (SBS) copolymers, a size exclusion chromatography combined with laser light scattering (SEC‐LLS) has been used to determine their weight‐average molecular weight (Mw) and radius of gyration (〈S2〉1/2), and a new method for the establishment of the Mark‐Houwink equation from one sample has been developed. Based on the Flory viscosity theory, we successfully have reduced the 〈S2〉1/2 values of numberless fractions estimated from many experimental points in the SEC chromatogram to intrinsic viscosities ([η]). For the first time, the dependences of 〈S2〉1/2 and [η] on Mw for the four‐arm star SBS in tetrahydrofuran at 25°C were found, respectively, to be 〈S2〉1/2 = 2.62 × 10−2 M (nm) and [η] = 3.68 × 10−2 M (mL/g) in the Mw range from 1.4 × 105 to 3.0 × 105. From data of [η] and 〈S2〉1/2 for linear and star SBS, we have obtained the information about the branching, namely, the ratios (g and g′) of 〈S2〉 and [η] for star SBS to that of the linear SBS of the same molecular weight, which agree with theoretical predictions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 961–965, 2005
Recombinant DNA techniques in diagnostic and preventive medicine
Authors: Hodgkinson Stephen , Scambler Peter
Published: February 2005

The introduction of recombinant DNA technology into the field of genetics has led to a rapid advancement of our knowledge of genes and genome structure. Such technology, applied to the human genome, has provided valuable information concerning the nature and possible treatment of inherited disorders. The possibility that this knowledge will pave the way for the correction of at least some of these disorders has captured the imagination of the informed public. In this review we look at the accomplishments of molecular pathologists to date and how new techniques are being applied to the study of inherited disease.
4‐Hydroxybutyric aciduria
Authors: Gibson Kenneth M.
Published: February 2005

Recent work has led to the discovery of six patients with 4‐hydroxybutyric acid‐uria, a severe hereditary human pathology characterized by the accumulation of a compound of known neuropharmacologic activity in body fluids. The enzymatic deficiency has been localized to succinic semialdehyde dehydrogenase, one of two enzymes involved in the metabolism of the neurotransmitter GABA. The disease is inherited as an autosomal recessive trait, and carrier detection has been accomplished by quantification of intermediate enzyme activities. The clinical, enzymatic and pharmacologic characteristics of this disease are reviewed here.
Retinoid‐regulated gene expression in normal and leukemic myeloid cells
Authors: Davies Peter J. A. , Moore William T. , Murtaugh Michael P.
Published: February 2005

Physiological concentrations of retinoic acid can induce acute alterations in the expression of the enzyme tissue transglutaminase in cultured macrophages. The induction of this enzyme offers a probe to study the mechanism of retinoid action in both normal and leukemic cells.
Problems and paradigms: Molecular problems of positional information
Authors: Wolpert Lewis
Published: February 2005

Enough is known about pattern formation in development to encourage investigations at the molecular level. A pressing need is to understand the molecular basis of positional value, which is similar to determination. It is suggested here that there is a molecular entity which varies in such a way that it corresponds with cell position. Other problems in pattern formation include thresholds, identification of morphogens, and the origin of handedness.
Challenges: Clinical applications of oncogene research
Authors: Krontiris Theodore G.
Published: February 2005

The following is adapted from the testimony, on 6 June 1984, of Dr T. G. Krontiris before the U.S. House Science and Technology Subcommittee on Investigations and Oversight, on the subject of oncogene research. In a previous report (BioEssays, 1, 3), the testimony of Dr C . J. Sherr, describing the molecular biology of oncogene action was given. Here, Krontiris describes the challenges in applying the new5ndings in diagnosis and therapy.
The location of maternal mRNA in eggs and embryos
Authors: Jeffery William R.
Published: February 2005

Recent studies have shown that some maternal mRNAs are localized in specific cytoplasmic regions of eggs and embryos and are rearranged in concert with the cytoplasmic movements that fix the embryonic axes. The localization and ooplasmic segregation of mRNA molecules may be mediated by their association with specific egg cytoskeletal domains.
Pseudogenes
Authors: Jeffreys Alec J. , Harris Stephen
Published: February 2005

Our chromosomes are full of the dead relics of genes. DNA analysis is beginning to unravel the origin and fate of these pseudogenes, and the influence that they may have on genome organization and evolution.
Effect of oncogenes on stem cells
Authors: Boettiger David
Published: February 2005

Stem cells may have a special importance in the neoplastic behavior of certain lineages as well as in the normal development of these tissues. The role of oncogenes, and their normal cellular analogues, in stem cell behavior is therefore of special interest. This review describes recent results on the effects of virally‐mediated src‐gene transfer into hemopoietic stem cells in the physiological and developmental properties of these cells.
Cystinosis: A defect of lysosomal cystine efflux
Authors: Schneider Jerry A.
Published: February 2005

The metabolic defect which results in the accumulation of cystine within tissues of children with the recessively inherited disease cystinosis has baffled investigators for almost half a century. Investigations by numerous laboratories have finally culminated in the delineation of the basic defect in this unusual disorder.
My favourite cell: Microinjected frog oocytes: A first‐rate test tube for studies on metabolism and its control
Authors: Ureta Tito , Radojković Jasna
Published: February 2005

Microinjection of frog oocytes, a technique whose usefulness for studies on gene expression is already established, may be similarly helpful for the unraveling of several enigmas of cellular metabolism and its organization.
The astral relaxation theory of cytokinesis revisited
Authors: White J. G.
Published: February 2005

Cytokinesis in animal cells is accomplished by the active constriction of the equatorial regions of a cell by an actomyosin‐containing contractile ring. The mitotic apparatus specifies the position and orientation of the furrow such that the mitotic spindle is always bisected. Global cortical contractions occur in the cortex of a cell prior to cytokinesis that are independent of the presence of the mitotic apparatus. It was proposed some years ago that the asters of the mitotic apparatus could act to relax the preformed cortical tension in their vicinity. This would produce a differential in tension between the equatorial regions and the adjacent regions of the cortex so that the equatorial regions would contract, forming a cleavage furrow. It can be shown that, as it stands, this theory cannot explain cleavage. However, if cortical contractile elements are assumed to be laterally mobile in the plane of the cortex, then the astral relaxation theory can account for many of the aspects of cleavage, including the formation of the contractile ring. Similar schemes may account for the behaviour of the lamellapodia of motile cells.
Molecular and mechanical aspects of helicoid development in plant cell walls
Authors: Neville A. C.
Published: February 2005

The view is presented that extracellular architecture in plant cell walls results from an interplay between molecular self‐assembly and mechanical reorientation due to growth forces. A key initial self‐assembly step may involve hemicelluloses. It is suggested that hemicelluloses may self‐assemble into a helicoid via a cholesteric liquid crystalline phase; the detailed molecular structure of hemicelluloses (stiff backbone, bulky side chains, and the presence of asymmetric carbon atoms) is shown to be consistent with cholesteric requirements for such self‐assembly. Since hemicelluloses are hydrogen‐bonded to the periphery of cellulose microfibrils, the cellulose could then itself become helicoidally arranged. Such ‘universal plywood’ structure is found in the walls of a wide variety of plants, and in several types of cell (including wood). The permanent effects of growth stresses on patterns seen in sections of helicoids are displayed by computer graphics plots, and the expected changes in stiffness are calculated.
Rates of molecular evolution: The hominoid slowdown
Authors: Goodman Morris
Published: February 2005

It is proposed that early in phylogeny a large proportion of amino acid substitutions were selectively neutral, but that bursts of adaptive substitutions during major radiations of life so increased selective constraints that most mutations in modern proteins are detrimental. Recent findings on DNA nucleotide sequences indicate that decreasing mutation rates further slowed the rate of molecular evolution in the lineage to humans.
Eicosanoids and aspirin in immune cell function
Authors: Bailey J. Martyn
Published: February 2005

Clonal expansion of T‐lymphocyte populations results from interactions of antigenic structures presented in combination with accessory cells (macrophages) and antibody recognition sites on the surface of T cells. The resulting activation of a membrane phospholipase C plays a crucial role in lymphocyte responses by releasing diglyceride and PIP3. The released diglyceride activates a cellular protein kinase C while PIP3 stimulates Ca2+ influx. Arachidonic acid released by the action of diglyceride lipase serves as substrate for the synthesis of bioactive eicosanoids (prostaglandins and leukotrienes) which in turn modulate cellular adenyl and guanyl cyclases. The eicosanoids serve as both intra‐ and extra‐cellular signals for lymphocytes, regulating the production and expression of lymphokines and mediating the complex interactions between the monocyte‐macrophage components and helper and suppressor T cells.

Aspirin and other anti‐inflammatory drugs stimulate mitogenesis by inhibiting production of the negative modulator prostaglandin E2 in accessory cells and by enhancing the production of the lymphokine 1L‐2 by producer T‐cells.
Gene analysis and its role in predicting susceptibility to disease
Authors: Humphries Steve , Barni Nazzarena
Published: February 2005

Recombinant DNA technology can now be applied to the analysis of complex human diseases such as polygenic disorders, where the inheritance of several unknown genes appears to be involved. We review here the progress in the analysis of genes which may be involved in the development of hyperlipidaemia, and show how the approach may be important in our understanding of the aetiology of coronary artery disease.
Regulation of the methionine regulon in Escherichia coli
Authors: Shoeman Robert , Redfield Betty , Coleman Timothy , Brot Nathan , Weissbach Herbert , Greene Ronald C. , Smith Albert A. , Saint‐Girons Isabelle , Zakin Mario M. , Cohen Georges N.
Published: February 2005

The genes involved in methionine biosynthesis are scattered throughout the Escherichia coli chromosome and are controlled in a similar but not coordinated manner. The product of the metJ gene and S‐adenosylmethionine are involved in the repression of this ‘regulon’.
Long‐distance signal transfer in transcriptionally active chromatin – how does it occur?
Authors: Luchnik Andrey N.
Published: February 2005

Gene transcription in eukaryotes is associated with conformational changes of a large area of chromatin adjacent to a gene. This rearrangement may involve the whole loop (topological domain) to which a given gene belongs.

Regulatory events associated with activation or inactivation of transcription are found to act through relatively short nucleotide sequences, often located several thousand base pairs apart from gene. These sequences, termed enhancers may act independently on their distance from or orientation with respect to the gene.

Both long‐range conformational rearrangements of chromatin and any long distance effects of enhancers may be associated with elastic torsional strain in DNA, arising in transcriptionally active chromatin loops. Enhancer effects, in particular, may be associated with conformational transitions in DNA competing for the energy deposited in the elastic spring of the DNA.
Transcriptional enhancers play a major role in gene expression
Authors: Rogers Bruce L. , Saunders Grady F.
Published: February 2005

Transcriptional enhancer sequences have been shown to play a pivotal role in the regulation of some highly expressed genes. First described in eukaryotic viruses, the discovery of enhancers has augmented the previously defined control‐sequence motifs to give a more complete understanding of eukaryotic transcriptional regulatory mechanisms. Some properties of enhancers that distinguish them from other regulatory sequences include their ability to function in a position‐ and orientation‐independent manner. Furthermore, the observation that some enhancers and transcriptional promoters exhibit tissue specificity in their activity has generated considerable interest. Enhancer activation is thought to involve sequence‐specific DNA‐binding proteins but the process by which this leads to an increase in the initiation of transcription remains obscure. Although viral enhancers are more fully characterized, several cellular enhancers have recently been identified. One such enhancer sequence has been detected in a 3′ flanking region of a highly expressed human placental lactogen gene. This enhancer can increase the transcriptional rate of an adjacent gene by at least 50‐fold.
Structural and functional domains on actin
Authors: Hambly Brett D. , Barden Julian A. , Miki Masao , Dos Remedios Cristobal G.
Published: February 2005

Actin plays several essential roles in cellular processes and is a vital component in the contractile apparatus. To accomplish its many cellular tasks, actin must interact with a wide range of other proteins in addition to self‐assembling into filaments. Characterization of these functional domains and localized binding regions on the actin monomer is therefore an important undertaking. Strategies for elucidating the many interaction sites include X‐ray diffraction, NMR and fluorescence spectroscopy, chemical modification, chemical cross‐linking, protein cleavage, and the study of sequence homologies between the many isotypes of actin. Based on these varied data, we discuss the possible spatial relationships between the interaction sites.
Cytoskeleton of embryonic skeletal muscle cells
Authors: Isobe Yuji , Shimada Yutaka
Published: February 2005

Cytoskeletal organization in embryonic skeletal muscle cells has been examined by transmission electron microscopy; the technique involves preparation using the platinum replication method of freezedried samples, with and without cryofracture. The cytoskeletons in developing muscle cells appear to play a role in preserving cell shape as well as in anchoring myofibrils to cell membrane.
The molecular biology of differentiation and proliferation using human myelogenous leukemia cells
Authors: Miller Carl , Koeffler H. Phillip
Published: February 2005

Cell lines and cell samples from patients provide opportunities for studying the mechanisms of leukemic cellular differentiation and proliferation. Phorbol esters and 1,25 dihydroxy vitamin D3 can induce differentiation of myeloid leukemic cells to macrophages. Differentiation to granulocytes can be induced by several different compounds. Myeloid differentiation is associated closely with the alteration in expression of several oncogenes. These regulatory events may be associated with the extent of methylation, unfolding or association of chromatin to the nuclear matrix. Oncogene amplification, mutation, or deletion can occur with malignant transformation. Future studies point to the development of specific pharmacological agents which can modify the neoplastic transformation.
The initiation of glycogen synthesis
Authors: Whelan William J.
Published: February 2005

The claim that glycogen contains protein was first made exactly 100 years ago and has been the subject of contention ever since. It has now been established that rabbit‐muscle glycogen contains a covalently bound protein of Mr 37,000, present in equimolar proportion to glycogen. The protein, named glycogenin, is joined to muscle glycogen via a novel linkage involving the hydroxyl group of tyrosine, a fact of possible significance in the light of insulin's message being transmitted by tyrosine phosphorylation. The protein is seen as the biogenetic precursor of glycogen. Its existence suggests an additional mode of regulation of glycogen metabolism since the amount, turnover and cellular location of glycogenin will influence the corresponding parameters for glycogen. A protein “primer” is suggested for the biogenesis of storage polysaccharides in general.
The role of actin polymerization in Amoebal Chemotaxis
Authors: Newell Peter C.
Published: February 2005

A very rapid cellular event that follows chemotactic stimulation of leucocyte and cellular slime mould amoebae is a massive polymerization of G to F actin and its association with the cytoskeleton. In the cellular slime moulds this event occurs within 3–5 sec of cell surface binding of chemoattractants. It is correlated with rapid pseudopodium extension and may be a cell orientation mechanism. Curiously, before an amoebae moves away in the direction of its new pseudopodium it rounds up or “cringes” for 10–20 sec, an event correlated with a massive actin depolymerization. Transduction of the chemotactic signal involves Ca2+ release from internal stores by inositol trisphosphate.
Molecular approaches to the study of mesoderm formation in amphibians
Authors: Brennan Sean
Published: February 2005

The mesoderm is the region of the embryo that gives rise to muscle, blood and connective tissues; it becomes segregated from the ectoderm and endoderm at gastrulation. Embryological studies have revealed, however, that the potential for certain embryonic cells to become part of the mesoderm is established well before gastrulation, most likely through an extracellular signalling process termed ‘induction’. The recent characterization of mesoderm‐specific mRNAs and proteins now permits an analysis of the very earliest events involved in the specification of the mesoderm at the molecular level. Such experiments should contribute to our understanding of the mechanisms involved in controlling cell differentiation.
Types of moral argument against embryo research
Authors: Williams Bernard
Published: February 2005

Almost all moral objections to embryo research depend on one version or another of a slippery slope argument. There is one absolutist consideration which may be thought to decide the question independently of that argument, to the effect that the early embryo simply is a human being. But any plausible use of that consideration itself relies on the slippery slope argument. This argument may use either of two ideas (or both): that to distinguish between the two cases is not reasonable or that it will not be effective. The argument turns out to be very largely an empirical, consequentialist argument, and its application to early embryo research to rest on doubtful assumptions.
Oncogenes and cell cycle genes
Authors: Ferrari Sergio , Baserga Renato
Published: February 2005

The relationships between oncogenes, cell‐cycle control genes, and growth‐related genes are described. An important generalization from the data is that all the oncogenes and cell‐cycle control genes so far characterized appear to be genes for growth factors or for receptors to growth factors, or to be involved in the general metabolism and structure of the cell. It is suggested that the transition in cell growth from quiescence to the proliferative state, in early G1, may be less specific than previously thought and involve a general priming of the cells for more specific later stimuli.
Phytochrome regulation of nuclear gene expression
Authors: Silverthorne Jane , Tobin Elaine M.
Published: February 2005

Phytochrome is known to regulate the expression of several major nuclearencoded polypeptides at the level of transcription. Both in vivo in vitro methods are currently being used to determine the step(s) between the light activation of phytochrome and changes in gene expression.
Human genetics: The molecular challenge
Authors: Bodmer Walter F.
Published: February 2005

The 1986 Cold Spring Harbor Symposium was on the subject of human genetics; it was the first symposium at Cold Spring Harbor on this topic since 1964. In the opening remarks for the conference, Walter F. Bodmer first summarized the progress in this field since 1964. He then described what is presently known about the functional complexity of the human genome and discussed the case for a definitive characterization and sequencing of the human genome. The following is an abridged and slightly adapted version of this talk; it is reproduced courtesy of the Cold Spring Harbor Laboratory © 1987.
Dynamic instability of microtubules
Authors: Cassimeris L. U. , Walker R. A. , Pryer N. K. , Salmon E. D.
Published: February 2005

Recent evidence shows that dynamic instability is the dominant mechanism for the assembly of pure tubulin in vitro and for the great majority of microtubules in the mitotic spindle and the interphase cytoplasmic microtubule complex. The basic concepts of this model provide a framework for future characterization of the molecular basis of spatial and temporal regulation of microtubule dynamics in the cell and the function of microtubule dynamics in motile processes such as chromosome movement.
Clonal heterogeneity in fibroblast phenotype: Implications for the control of epithelial‐mesenchymal interactions
Authors: Schor Seth L. , Schor Ana M.
Published: February 2005

The widespread distribution of fibroblasts underlines their central role in mammalian physiology, development and ageing. The existence of developmentally regulated and site‐specific phenotypic variation in fibroblasts is well documented. Recent evidence has revealed heterogeneity within the fibroblast population of a given tissue at a specified development stage. The relative proportion and tissue distribution of distinct fibroblast subsets must have important consequences in the control of connective tissue and adjacent epithelial functions in health and disease.
Memories of fos
Authors: Curran Tom , Morgan James I.
Published: February 2005

Induction of c‐fos expression occurs following treatment of diverse cell types with agents that trigger mitogenesis, differentiation or membrane depolarization. We suggest that c‐fos may be regarded as a marker for a set of rapidly induced genes (termed cellular immediate‐early genes) whose function is to couple extracellular stimulation to long‐term responses. In the brain, these genes may contribute to the adaptive alterations involved in neuronal plasticity.
Ribosomal protein autoantibodies in systemic lupus erythematosus
Authors: Elkon Keith , Bonfa Eloisa , Skelly Susan , Weissbach Herbert , Brot Nathan
Published: February 2005

Autoantibodies to three eukaryotic 60S ribosomal phosphoproteins P0, P1 and P2 have been found in the sera of 10–20% of patients with systemic lupus erythematosus (SLE). These three proteins share a common epitope contained within the carboxy terminal 22 amino acids of each protein. Because central nervous system disturbances, with major behavioural disorders, occur in a significant fraction of SLE patients, the antiribosomal autoantibodies were measured in this subset of SLE individuals to determine whether or not there was an association. This antibody is present in 90% of SLE patients who were diagnosed as having psychosis, secondary to the disease.
Regulation of chromosomal replication and transcription during early mammalian development
Authors: DePamphilis Melvin L. , Wassarman Paul M.
Published: February 2005

Many principles of eukaryotic DNA replication and its relationship to transcription have been revealed by studying the replication of animal virus chromosomes. Now microinjection of viral DNA into eggs and embryos is providing clues about regulation of chromosomal replication and transcription during early mammalian development.
The membrane skeleton – A distinct structure that regulates the function of cells
Authors: Fox Joan E. B. , Boyles Janet K.
Published: February 2005

It has long been known that the red blood cell contains a membrane skeleton that stabilizes the plasma membrane, determines its shape, and regulates the lateral distribution of the membrane glyco‐proteins to which it is attached. The way in which these functions are regulated in other cells has not been understood. It has now been shown that platelets also contain a membrane skeleton. In contrast to the membrane skeleton of the red blood cell, the platelet membrane skeleton has actin‐binding protein, not spectrin, as a major component. The platelet membrane skeleton regulates the same cellular functions as the red blood cell membrane skeleton. Other cells may contain a membrane skeleton that is critical to their viability and normal functioning.
The role of the otu Gene in Drosophila oogenesis
Authors: King Robert C. , Storto Patrick D.
Published: February 2005

The ovarian tumor (otu) gene behaves as if it encodes a product (OGP) which is required during several early steps in the transformation of oogonia into functional oocytes. The ovarian phenotypes produced by various EMS‐induced mutations can be explained as graded responses by individual mutant germ cells to the different levels of functionally active OGP they themselves synthesize. In addition, genetic evidence suggests that otu also encodes a second product that is utilized late in oogenesis. Molecular studies of the otugene demonstrate that it does transcribe at least two ovaryspecific RNAs. The possible function of the otu product in the cellular divisions that give rise to the oocyte and its sister nurse cells is discussed.
Early embryogenesis in Caenorhabditis elegans: The cytoskeleton and spatial organization of the zygote
Authors: Strome Susan , Hill David P.
Published: February 2005

Early embryogenesis of Caenorhabditis elegans provides a striking example of the generation of polarity and the partitioning of cytoplasmic factors according to this polarity. Microfilaments (MFs) appear to play a critical role in these processes. By visualizing the distribution of MFs and by studying the consequences of disrupting MFs for short, defined periods during zygote development, we have generated some new ideas about when and how microfilaments function in the zygote.
Eukaryotic DNA replication reconstituted outside the cell
Authors: Blow J. Julian
Published: February 2005

Our potential for dissecting the complex processes involved in eukaryotic DNA replication has been dramatically increased with the recent development of cell‐free systems that recreate many of these processes in vitro. Initial results from these systems have drawn together work on the cell cycle, the enzymology of replication, and the structure of the nucleus.
Expression of glycoconjugates during development of the vertebrate nervous system
Authors: Schwarting Gerald A. , Yamamoto Miyuki
Published: February 2005

There is increasing evidence that carbohydrate antigens act as cell recognition molecules in the highly organized structure of the nervous system. These carbohydrate antigens may be expressed as glycolipids, glycoproteins or proteoglycans, and in some cases all three forms of these glycoconjugates, expressing identical carbohydrate epitopes, can be detected in a specific brain region. This article summarizes recent studies concerning the expression of glycoconjugates during development of the vertebrate central nervous system. These findings are discussed in association with current models of glycoconjugate function.
Is there induced DNA repair in mammalian cells?
Authors: Denhardt David T. , Kowalski Jacek
Published: February 2005

The problem we discuss is whether mammalian cells possess genes whose expression is specifically enhanced by DNA damage in order to cope with the damage. The paradigm is the SOS response in E. coli. We conclude that there is compelling evidence that DNA‐damaging agents do affect gene expression, and that mutation frequencies are increased, but proof that a repair process per se is induced remains elusive. We offer here the hypothesis that recognition of the presence of DNA damage by poly(ADPribose) polymerase effects preprogrammed changes in gene expression.
recA‐dependent DNA repair processes
Authors: Smith Kendric C. , Wang Tzu‐Chien V.
Published: February 2005

UV‐radiation‐induced lesions in DNA result in the formation of: (1) excision gaps (i.e. a lesion is excised, leaving a gap), (2) daughter‐strand gaps (i.e. a lesion can be skipped during replication, leaving a gap), and (3) double‐strand breaks (i.e. the DNA strand opposite a gap can be cut). In Escherichia coli, the recA gene product is involved in repairs of all three types of lesions – repair of daughter‐strand gaps (2) and double‐strand breaks (3) constitutes post‐replication repair. The evidence suggests, furthermore, that recA‐dependent repair of excision gaps (1) produced in DNA replicated prior to UV irradiation (pre‐replication repair) appears to occur by similar mechanisms.
Proteinase inhibitor gene families: Strategies for transformation to improve plant defenses against herbivores
Authors: Ryan Clarence A.
Published: February 2005

Recent evidence indicates that the presence of serine proteinase inhibitors in plant leaves can reduce predation by insects. Plants can now be transformed with proteinase inhibitor genes with strong promoters to express the inhibitor proteins in relatively high levels at specific times. Inhibitors having variable specificities against digestive proteinases of insects and pathogens can now be assessed for their possible role(s) in natural plant defense and for their potential usefulness in protecting crop plants against herbivores.
The molecular biology of brain and mind development
Authors: Epstein Herman T.
Published: February 2005

The recent dramatic development of molecular neurobiology has focused almost entirely on biological events in individual brain cells, and it seems that many of the goals of such work will soon be attained. Yet, when we attain those goals, we will still have to ask how this information will enable us to understand the properties of brain cell collectivities and their presumptive roles in higher brain functions. Even general ideas about those functions are not yet well defined. Therefore, it seems worthwhile to start studying correlations of the molecular events to these higher functions to help delineate the molecular aspects that need study.

It is readily appreciated that we cannot tell what other animal species see, hear, taste, smell and feel when touching something, though we can foresee the time when we will be able to detail the biochemical and biophysical consequences of all inputs to those senses. Thus, however deep our understanding of the biology of those species, we are unable to establish relations between their biological responses to inputs and their presumptive mental perceptions. Even though humans can use language to talk about those perceptions, we cannot even verify whether someone else's perceptions are the same as our own, as with the old question of whether two individuals see the same thing when viewing something blue. Questions about still higher mental functions of human brains are even less accessible to analysis and can be approached at best, by using correlations. In this article are a number of such questions and their current correlation‐level answers.
Focal contacts: Transmembrane links between the extracellular matrix and the cytoskeleton
Authors: Burridge Keith , Fath Karl
Published: February 2005

The sites of tightest adhesion that form between cells and substrate surfaces in tissue culture are termed focal contacts. The external faces of focal contacts include specific receptors, belonging to the integrin family of proteins, for fibronectin and vitronectin, two common components of extracellular matrices. On the internal (cytoplasmic) side of focal contacts, several proteins, including talin and vinculin, mediate interactions with the actin filament bundles of the cytoskeleton. The changes that occur in focal contacts as a result of viral transformation are discussed.
Food, reproduction and L'ongevity: Is the extended lifespan of calorie‐restricted animals an evolutionary adaptation?
Authors: Holliday Robin
Published: February 2005

Calorie restriction results in an increased lifespan and reduced fecundity of rodents. In a natural environment the availability of food will vary greatly. It is suggested that Darwinian fitness will be increased if animals cease breeding during periods of food deprivation and invest saved resources in maintenance of the adult body, or soma. This would increase the probability of producing viable offspring during an extended lifespan. The diversion of limited energy resources from breeding to maintenance of the soma is seen as an evolutionary adaptation, fully compatible with the ‘disposable soma’ theory of the evolution of ageing.
Metabolic Compartmentation
Authors: Spivey H. O. , Merz J. M.
Published: February 2005

Evidence for the association of ‘soluble’ enzymes in vivo is extensive and compelling. These associations occur in all compartments of the cell of both prokaryotes and eukaryotes. Several factors present in vivo promote these associations among enzymes whose association in vitro is often too weak to detect. Several physiological advantages of the associated enzyme complexes can be identified, most (but not all) of which are the consequence of microcompartmentation of metabolites (substrate channeling). Substrate channeling of intermediates by either a ‘direct transfer’ process or ‘proximity effects’ can occur. The latter mechanism does not require the special molecular features needed for the direct transfer mechanism and may, therefore, exist in more general situations in the cell. Criticisms of these views are discussed. We argue that these criticisms have been largely answered by experiment and theory in recent years. Studies on simple systems in vitro, nevertheless, contribute important insights concerning the more complex phenomena in vivo.
Unusual features of cereal seed protein structure and evolution
Authors: Kreis Martin , Shewry Peter R.
Published: February 2005

The alcohol‐soluble (prolamin) storage proteins of barley, wheat and rye vary in their structures, but all have two features in common: the presence of distinct structural domains differing in amino acid compositions, and of repeats within one of these domains. Detailed comparisons of amino acid sequences show that all appear to have evolved from a single ancestral gene consisting of three short related regions (called A, B and C). Regions related to A, B and C are also present in the minor prolamins of maize and in three other groups of seed proteins: inhibitors of α‐amylase and /or trypsin from cereals. 2S storage globulins from several dicotyledonous species and a 2S albumin from sunflower. It is suggested that these proteins together constitute a protein superfamily with limited sequence homology.