bluuebunny/crossref_metadata_2025 huggingface dataset:
Retesting of Liquefaction/Nonliquefaction Case Histories in the Imperial Valley
Authors: Moss Robb E. S. , Collins Brian D. , Whang Daniel H.
Published: February 2005

This paper describes the retesting of liquefaction and nonliquefaction field case histories in the Imperial Valley using the electric cone penetration test (CPT). Subsurface testing of the River Park and Heber Road sites first occurred following the 1979 Imperial Valley earthquake (Bennett et. al. 1981, Youd and Bennett 1983). These two sites are rich in information because they have experienced several earthquakes in recent history, have been subjected to moderate levels of strong ground shaking, the liquefiable layers have appreciable fines content, and the sites contain a number of high-quality nonliquefied data points. The recent liquefaction case history database for probabilistic assessment of liquefaction triggering by Moss et. al. (2003), is based primarily on data acquired using the modern electric cone following ASTM D5778. Case histories previously explored with a cone not adhering to current ASTM standards may introduce significant epistemic uncertainty into the assessment of liquefaction potential and are considered sub-optimal for probabilistic analysis purposes. This paper describes the acquisition and analysis of modern electric cone data at the Heber Road and River Park sites. These important sites can now be incorporated into the probabilistic CPT-based liquefaction case history database and used for back-analysis of liquefaction triggering. Discussed are the effects of ground motion character and frequency content on liquefaction at these two sites and how this influences the results using a simplified liquefaction procedure.
A Graves’ Disease-Associated Kozak Sequence Single-Nucleotide Polymorphism Enhances the Efficiency of CD40 Gene Translation: A Case for Translational Pathophysiology
Authors: Jacobson Eric M. , Concepcion Erlinda , Oashi Taiji , Tomer Yaron
Published: February 2005

We analyzed the mechanism by which a Graves’ disease-associated C/T polymorphism in the Kozak sequence of CD40 affects CD40 expression. CD40 expression levels on B cells in individuals with CT and TT genotypes were decreased by 13.3 and 39.4%, respectively, compared with the levels in CC genotypes (P = 0.012). Similarly, Rat-2 fibroblasts transfected with T-allele cDNA expressed 32.2% less CD40 compared with their C-allele-transfected counterparts (P = 0.004). Additionally, an in vitro transcription/translation system showed that the T-allele makes 15.5% less CD40 than the C-allele (P < 0.001), demonstrating that the effect of the single-nucleotide polymorphism (SNP) on CD40 expression is at the level of translation. However, the SNP did not affect transcription, because the mRNA levels of CD40, as measured by quantitative RT-PCR, were independent of genotype. Therefore, our results may suggest that the C allele of the CD40 Kozak SNP, which is associated with Graves’ disease, could predispose to disease by increasing the efficiency of translation of CD40 mRNA.
Synthesis and characteristics of a semi‐interpenetrating polymer network based on chitosan/polyaniline under different pH conditions
Authors: Kim Seon Jeong , Shin Su Ryon , Spinks Geoffrey M. , Kim In Young , Kim Sun I.
Published: February 2005

Chitosan/polyaniline (PANi) semi‐interpenetrating network (semi‐IPN) polymers were prepared under the condition of HCl aqueous solution (pH < 1). The structure and half oxidation state of emeraldine base PANi, adjusted to pH < 1, underwent changes of structure and electrical properties. Changes of structural properties were investigated using FTIR spectroscopy, solid‐state 13C‐NMR, and wide‐angle X‐ray diffraction. Spectroscopic studies revealed that the PANi was converted to its pH‐switched emeraldine salt form. The surface conductivity of the semi‐IPN depended on the chitosan/PANi weight ratio and the pH condition. The conductivity of the semi‐IPNs increased with increasing PANi content with adjusted pH < 1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 867–873, 2005
The effect of loading rate on the fracture toughness of fiber reinforced polymer composites
Authors: Jacob George C. , Starbuck J. Michael , Fellers John F. , Simunovic Srdan , Boeman Raymond G.
Published: February 2005

This article is a detailed review of the strain rate dependence of fracture toughness properties in polymer composite materials. An attempt is made to draw together all the strain rate studies done in the past and to elucidate the reasons given by the authors of the reviewed papers for the trends resulting from their studies to better understand the strain rate effects on the fracture toughness of fiber reinforced polymer composite materials. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 899–904, 2005
Preparation and characterization of ultraviolet‐curable nanocomposite coatings initiated by benzophenone/n‐methyl diethanolamine
Authors: Li Fusheng , Zhou Shuxue , Gu Guangxin , You Bo , Wu Limin
Published: February 2005

A series of ultraviolet‐curable nanocomposite coatings were prepared with condensed nanosilica particles and with benzophenone/n‐methyl diethanolamine as the initiator. The nanosilica that incorporated into the nanocomposites did not aggregate even when the nanosilica concentration was as high as 22.5%. Adding nanosilica increased the curing speed, thermal stability, and ultraviolet shielding properties of the nanocomposites without reducing the transparency of the ultraviolet‐curing coatings. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 912–918, 2005
DNA transposition – a major contributor to plant chromosome structure
Authors: Flavell R. B.
Published: February 2005

Higher plant nuclear genomes contain many families of dispersed repeats that change during evolution. Recent evidence from studies on genetically defined transposable elements raises the possibility that many of the dispersed repeats are remnants of such elements. Transposition of DNA has also occurred between mitochondria, chloroplasts and nuclei, a fact that underlines the major role played by DNA transposition in determining the structure of plant genomes.
Eukaryotic cloning vectors based on bovine papilloma viruses
Authors: DiMaio Daniel
Published: February 2005

The cloning of eukaryotic genes by standard recombinant DNA techniques permits their structural characterization. However, analysis of the expression properties of these genes often requires their introduction into and replication within eukaryotic cells in culture. Certain viral vectors based on the papilloma viruses may prove to be especially important in such investigations. These ‘shuttle vectors’, capable of replication in both bacterial and eukaryotic cells, have already provided several findings of interest about the relationship between eukaryotic gene structure and function. Further analysis of these vectors and their properties promises to enhance their use as investigative tools.
New uses for endothelial cell culture
Authors: Ryan Una S.
Published: February 2005

Endothelial cells in culture have, in the past, been a valuable but capricious tool to test hypotheses on the role of components of the blood vessel wall in such functions as blood pressure homeostasis, hemostasis, permeability, transport of macromolecules and the processing of circulating biologically active substances. Now techniques are becoming available for raising long‐term, large‐scale cultures that can be maintained reproducibly and without loss of phenotypic characteristics. The outlook for establishing endothelial cell factories invites speculation on some far‐reaching possibilities, such as endothelial cell banks that could be used for seeding autogenous cells on vascular prostheses, artificial kidney tubing, heart valves, or corneas, or for virus production, or for synthesis by endothelial cells of products at present beyond the reach of bacterial cells.
The influence of alcohol on female germ cells
Authors: Kaufman M. H.
Published: February 2005

The teratogenic effect of ethanol on human and animal embryos is now well documented. Recent studies have clearly demonstrated that ethanol and related spindle‐acting agents may additionally interfere with normal meiotic chromosome segregation during oocyte maturation, leading to the production of aneuploid embryos. The mode of action, and potential hazard posed by these agents is considered.
Membrane tubulin: Fact or fiction?
Authors: Rubin Robert W.
Published: February 2005

Tubulin is the ubiquitous protein that makes up the walls of the cytoskeletal elements known as microtubules. These 20 nm diameter cylindrical fibers are the spindle fibers for mitosis, provide the skeletal framework for cellular elongation, constitute the major structural and motile elements of cilia and flagella and probably play a number of other roles in eukaryote cells. In the electron microscope, they are never seen to attach or protrude directly into or on cellular membranes. It was therefore with much skepticism that cell biologists responded to recent claims purporting to show that tubulin is (or can be) a membrane protein. This skepticism comes from a bias based on the generally understood function of cytoskeletal proteins as representing the intracellular ‘bones’ of cells. The traditional thinking was that microtubules may attach to cellular membranes but only via a cross‐linking connecting protein. In recent years, however, an increasing number of workers have come to believe that tubulin can exist as a normal membrane protein possibly independent of its role in microtubule function.
Artificial photosynthesis – an example of membrane mimetic chemistry
Authors: Fendler Janos H.
Published: February 2005

The goal of constructing artificial photosynthetic assemblies is to use sunlight for the generation of hydrogen from water; the hydrogen obtained should be an ideal energy source. The use of surfactant vesicle entrapped‐catalyst coated colloidal semiconductors and sacrificial electron donors for photosensitized water reduction illustrates how chemists mimic photosynthesis.
What's new: Hybridoma technology in immunocytochemistry
Authors: Cuello A. Claudio , Milstein Cesar
Published: February 2005

What's New will present discussions of new methodologies or improvements of previously developed techniques. In this article, A. C. Cuello and C. Milstein discuss the present status of monoclonal antibody technology..
The relationship between human histone gene expression and DNA replication
Authors: Stein Gary S. , Stein Janet L.
Published: February 2005

There is now a wealth of information that histone proteins play a primary role in the structural and transcriptional properties of chromatin, the protein‐DNA complex which constitutes the eukaryotic genome1, 2. In light of the crucial role of histones in cellular function, it is not surprising that their structural genes are found to be controlled in conjunction with the cell cycle, with the synthesis of most histones tightly coupled to nuclear DNA replication. The evidence suggests that this linkage between DNA replication and histone synthesis involves the regulated adjustment of histone mRNA levels through both transcriptional and posttranscriptional control process. The possible mechanisms underlying these diverse control processes are described here.
The molecular genetics of the components of complement and autoimmune diseases
Authors: Porter R. R.
Published: February 2005

The molecular components of complement are a major part of the armoury of the mammalian immune system, being required for the lysis of antibody‐targeted cells. Several of the complement proteins are known to be encoded by genes within the major histocompatibility complex (MHC). Molecular analysis of these genes is providing new information on the basis of complement action and the possible roles of this system in autoimmune disease.
What'S new: The role of chaotropic salts in two‐phase gene diagnosis
Authors: Gillespie David , Caranfa Mary Jo , Bresser Joel
Published: February 2005

The preparation of samples for gene diagnosis is time‐consuming, labor‐intensive and costly. These problems can be overcome by dissolving a biological source in a strong solution of a chaotropic salt, then filtering the solution through an immobilizing membrane. Conditions exist for causing the selective immobilization of either DNA or mRNA. The resultant membrane is immediately ready for reaction with labeled gene probes.
Molecular genetic studies on the thiobacilli and the development of improved biomining bacteria
Authors: Woods David , Rawlings Douglas
Published: February 2005

Acidophilic autotrophic thiobacilli, which are able to oxidize metal and solubilize sulphide ores, are used industrially to leach metals from mineral ores. Genetic manipulation of the thiobacilli has the potential for the production of leaching bacteria with desirable characteristics for industry. In this review we examine the development of genetic systems in the thiobacilli and the present status of molecular genetics in the group.
Bent DNA for gene regulation and DNA packaging
Authors: Widom Jonathan
Published: February 2005

Recent work on kinetoplast DNA and on CAP‐DNA and Eco RI‐DNA complexes shows that certain sequences cause DNA to be highly bent, and that other sequences bend in response to the sequence‐specific binding of proteins. These results demonstrate that alterations of DNA structure may facilitate gene regulation and DNA packaging.
Molecular basis of experimental diabetes: Degeneration, oncogenesis and regeneration of pancreatic B‐cells of islets of Langerhans
Authors: Okamoto Hiroshi
Published: February 2005

Insulin is synthesized in pancreatic B‐cells of islets of Langerhans. Understanding the mechanisms of action of B‐cytotoxins on pancreatic islets seems to be important for elucidating not only the causes of diabetes mellitus but also its prevention.
Supercoiled loops and the organization of replication and transcription in eukaryotes
Authors: Zehnbauer Barbara A. , Vogelstein Bert
Published: February 2005

The nuclear DNA of eukaryotes is organized into a series of loops each topologically anchored by elements of the nuclear matrix. Evidence is reviewed which indicates that the anchorage points of the loops are formed by transcriptionally active genes and that individual loops function as replicons. The data suggests a specific model for coupling of DNA replication and transcription in eukaryotes.
This is ICSU: The international union of microbiological societies (IUMS): What is it? what does it do?
Authors: Gerhardt Philipp
Published: February 2005

Microbiological scientists around the world often have only a vague notion about the nature of the international organization with which their national microbiological societies are affiliated. This article provides answers to questions that are usually raised about IUMS; it is reproduced with permission from Microbiological Sciences.
Roots: Cell fusion
Authors: Harris Henry
Published: February 2005

There is a tendency for living things to join up, establish linkage, live inside each other, return to earlier arrangements, get along, whenever possible. This is the way of the world.

The new phenomenon of cell fusion, a laboratory trick on which much of today's science of molecular genetics relies for its data, is the simplest and most spectacular symbol of the tendency. In a way, it is the most unbiologic of all phenomena, violating the most fundamental myths of the last century, for it denies the importance of specificity, integrity, and separateness in living things. Any cell ‐ man, animal, fish, fowl, or insect ‐ given the chance and under the right conditions, brought into contact with any other cell, however foreign, will fuse with it. Cytoplasm will flow easily from one to the other, the nuclei will combine, and it will become, for a time anyway, a single cell with two complete, alien genomes, ready to dance, ready to multiply. It is a Chimera, a Griffon, a Sphinx, a Ganesha, a Peruvian God, a Ch'i‐lin, an omen of good fortune, a wish for the world.
Genetic and molecular analyses of Drosophila contractile protein genes
Authors: Fyrberg Eric A.
Published: February 2005

To further comprehend how synthesis and assembly of myofibrillar components is regulated, several laboratories have undertaken genetic studies of muscle development in Drosophila melanogaster. This small fly lends itself well to classical and molecular genetic approaches, and possesses a set of muscle fibers, termed indirect flight muscles (IFM), which is particularly advantageous for such investigations. Structural and functional analyses of cloned Drosophila contractile protein genes have revealed that protein isoforms can be specified either by multigene families or by differentially splicing primary transcripts of a single gene. Characterization of mutations which disrupt flight muscle development has so far revealed that profound abnormalities are caused by defective alleles of actin, tropomyosin, and myosin heavy‐chain genes. Muscle defects associated with particular alleles can be alleviated by integration of corresponding wild‐type gene copies into germ‐line chromosomes. Strategies for further applying genetic techniques to investigations of Drosophila muscle development are discussed.
Spacers and processing of large ribosomal RNAs in Escherichia coli and mouse cells
Authors: Schlessinger D. , Bolla R. I. , Sirdeshmukh R. , Thomas J. R.
Published: February 2005

The formation of mature large rRNAs from larger primary transcripts is very different in bacterial and mammalian cells. In both, cotranscription can help to assure the coordinated production of various rRNA species. However, in bacteria, processing is ordered, initiated by cleavages at double‐stranded stems which enclose the mature sequences; several cleavages are required to produce each mature terminus; and the final steps occur in polysomes, apparently linked to continued protein synthesis. In mouse cells, in contrast, cleavages generate nearly all mature termini stochastically and directly, with no evidence for double‐stranded stems as cleavage signals; and processing occurs in the nucleolus, long before any new rRNA chains arrive in polysomes. Spacer sequences also serve different potnetial functions at the evolutionary extremes. In bacteria, transcribed spacer sequences are associated with different secondary structures in the pre‐rRNA compared to the mature rRNA, and these may promote ribosome formation. In mammalian cells, analyses are too premature to assign any comparable function to transcribed spacer sequences, but the non‐transcribed spacers are probably critical in the organization and replication of nucleoli, functions that are absent from bacteria.
Problems and paradigms: What are the causes of morphogenesis?
Authors: Goodwin B. C.
Published: February 2005

Problems and Paradigms is a feature series devoted to discussions of major problems in biology. Past contributions have dealt with the selector gene hypothesis, problems of pattern formation, the phenomenon of paramutation, theories of aging, and the origins of life. In this article, Brian C. Goodwin discusses the problem of morphogenesis, in terms of the idea of the genetic program and in the light of recent findings.
Roots: The origins of molecular genetics: One gene, one enzyme
Authors: Horowitz Norman H.
Published: February 2005

Roots presents articles on landmark discoveries that laid the basis for contemporary molecular and cellular biology. In this article, N. H. Horowitz, Professor Emeritus at the California Institute of Technology, and a former associate of George Beadle's, reviews the work that led to the one gene–one enzyme hypothesis.
Non‐enzymatic modification of proteins by steroids: Pathological implications for autoimmunity and glucocorticoid toxicity
Authors: Bucala Richard , Cerami Anthony
Published: February 2005

Certain steroids can react with proteins to form stable, covalent addition products. 16α‐hydroxyestrone and the glucocorticoids, for example, contain ketol moieties which permit them to react non‐enzymatically with proteins by forming Schiffbase rearrangement products with lysine residues. The oral contraceptive agent, 17α‐ethinylestradiol, can add to proteins after being enzymatically activated by microsomal oxidation. Elevated plasma levels of these steroids result in an increased amount of protein modification in vivo. Recent investigations have linked the occurrence of steroid‐modified proteins with pathological sequelae associated with high steroid levels.
Innovations in communication: Origin of Biochemical & biophysical research communications
Authors: McElroy W. D.
Published: February 2005

This feature series will present short articles on the development of new journals and forms of communication in Biology.
A biochemical pathway for a cellular behaviour: pHi, phosphorylcreatine shuttles, and sperm motility
Authors: Shapiro Bennett M. , Tombes Robert M.
Published: February 2005

Sperm motility and respiration are tightly coupled processes, both activated by an increased intracellular pH (pHi). As the sperm pHi increases, the flagellar motor driving motility is activated, leading to ATP consumption. Energy for motility is provided by mitochondrial respiration; energy transport from sperm mitochondrion to tail involves distinct isozymes of creatine kinase that effect a phosphorylcreatine shuttle. The activation of sperm motility and respiration can be described as a linked series of biochemical reactions that form a cell behavioural pathway analogous to the reaction sequences of intermediary metabolism.
Human p53 and human tumours
Authors: Crawford Lionel
Published: February 2005

In normal human cells, a protein with a molecular weight of about 53,000 (p53) is present at a low level, detectable only by sensitive assays. When the cells are infected with some DNA tumour viruses or transformed by the same viruses, the amount of this protein increases dramatically, and much of it is found in a physical association with the virus‐coded protein that causes the transformation. The increase in amount and, incidentally, stability of p53 is not peculiar to virus‐transformed cells, but also occurs in cells transformed by chemicals or radiation where there is no sign of any virus being involved (reviewed by Crawford).1 Cells in culture are not the same as cells in a patient, but these observations do raise questions about the possible involvement of p53 in human tumours.
Cauliflower mosaic virus: Pathways of infection
Authors: Hull Roger , Covey Simon N.
Published: February 2005

This short review summarizes what is known, and points out some of the unknown features, about the molecular biology of the natural spread of cauliflower mosaic virus into a susceptible host and its subsequent replication in that host.
BUdR, probability and cell variants: Towards a molecular understanding of the decision to differentiate
Authors: Wright Woodring E.
Published: February 2005

The mechanism(s) by which the thymidine analogue 5‐bromodeoxyuridine (BUdR) specifically inhibits the expression of differentiated functions is poorly understood, as are the ways in which cells regulate processes exhibiting probabilistic aspects. I have developed a theoretical model for the regulation of the decision of myogenic cells to differentiate that can explain both of the above phenomena. This model provided a strategy for isolating myoblast variants that had amplified the expression of the factors regulating the decision to differentiate. These myoblasts served as the source of mRNA for making and screening a cDNA library in order to isolate these factors. The successful cloning of these genes should represent a major advance in our understanding of the molecular basis for the major coordinated changes in gene expression that accompany cell differentiation.
A case for human tumor‐suppressor genes
Authors: Stanbridge Eric J.
Published: February 2005

Much of the recent work on oncogenes has been interpreted as signifying that the cancerous phenotype is caused by the direct expression of ‘dominantly‐acting’ oncogenes. On the other hand, numerous somatic cell hybridization experiments suggest that there are potent tumour‐suppressor genes in the genome. The conflict between the observations and the possible nature of the relationships between oncogenes and tumour‐suppressor are discussed.
Synthetic metalloporphyrins: A class of compounds of pharmacological interest
Authors: Kappas Attallah , Drummond George S.
Published: February 2005

Studies of the regulation of heme oxygenase by synthetic metalloporphyrins reveal that within this group of compounds there exist both inducers and inhibitors of the synthesis of this enzyme or of its catalytic function. The ability of metalloporphyrins to alter heme catabolism is of considerable experimental and clinical interest since such alterations may have consequences for other aspects of heme homeostasis, including its synthesis and its function in the form of cytochrome(s) P‐450. Examples of the metabolic effects – and their potential clinical and pharmacological consequences – produced by two synthetic metalloporphyrins, Sn‐protoporphyrin and Co‐protoporphyrin, are discussed.
Transcriptional regulation of mammalian ribosomal RNA genes
Authors: Muramatsu Masami
Published: February 2005

Eukaryotic genes are divided into three categories according to the machineries by which they are transcribed. Ribosomal RNA genes (rDNA) are the only ones that are transcribed by RNA polymerase I and are under different control from other genes transcribed by RNA polymerase II or III. None the less, the regulation of rDNA is of prime interest in view of its close relationship to cell growth and differentiation. In this review I shall discuss the recent progress in the study of transcription mechanisms of rDNA by the RNA polymerase I system. The structure of the rDNA promoter and the presence of possible upstream enhancer regions will be described. In addition, factors involved in the transcription initiation of this gene will be discussed with special reference to the formation of an initiation complex.
What the papers say: Molecular karyotypes: Separating chromosomes on gels
Authors: Corcoran Lynn M.
Published: February 2005

For many years, there has been a gap in our capacity to study the structure and organization of chromosomal DNA molecules. The very small genomes of some viruses and bacteriophages (≤ 50,000 bp or 50 kb) are amenable to analysis by conventional gel electrophoresis, while the extremely large DNA molecules (> 100,000 kb) comprising the chromosomes of higher eukaryotes have been analysed under the light microscope, using a range of banding and in situ hybridization techniques. However, intact DNA molecules with sizes between these two extremes have been largely inaccessible experimentally. This gap has recently been bridged with the development of two‐dimensional electrophoretic procedures that allow the separation and purification of chromosome‐sized DNA molecules ranging from ∼ 50 kb to several thousand kb.1–3 There are currently two variations of the technique in use: pulsed field gradient (PFG) gel electrophoresis1,2 and orthogonal‐field‐alteration gel electrophoresis (OFAGE).3 Both are based on a common principle, differing primarily in the geometry of the electrodes. Already, they have been employed to determine the approximate chromosome sizes and numbers for a variety of lower eukaryotes, including yeast and several protozoa.2–10 These ‘molecular karyotypes’ provide fundamental information about the genomic organization of each organism, and allow very rapid construction of linkage maps. Surprisingly, they have also revealed a remarkable plasticity in the genomes of several lower eukaryotes.
Transcriptional regulatory sequences from plant viruses
Authors: Kridl Jean C. , Goodman Robert M.
Published: February 2005

Two groups of plant viruses have DNA in their genomes. One group, the caulimoviruses, are non‐integrating retroviruses that package dsDNA in virions. The other group, the geminiviruses, package small circular ssDNA and include the only DNA viruses known with bipartite genomes. The regulation of transcription of these viruses is not well characterized, but recent work is beginning to yield interesting results. Regulatory sequences from these viruses function in cells of species that are not hosts of the virus and are finding use in constitutive expression of chimeric genes in transformed plants. Development of vectors based on plant viruses requires further characterization at the molecular level of viral life cycles.
The role of cAMP in controlling yeast cell division
Authors: Ishikawa Tatsuo , Uno Isao , Matsumoto Kunihiro
Published: February 2005

The studies on the cAMP‐requiring mutants and their suppressors in the yeast, Saccharomyces cerevisiae, revealed that cAMP‐dependent protein phosphorylation is involved in the G1 phase of the cell cycle, in conjugation, and in the post‐meiotic stage of sporulation, and that inhibition of cAMP‐dependent protein phosphorylation is required to induce meiotic division.
Coordinated assembly of the developing Egg
Authors: Tata Jamshed R.
Published: February 2005

The developing vertebrate oocyte autonomously makes most of the components of the machinery for DNA and protein synthesis, as well as ‘maternal’ mRNAs, needed immediately after fertilization. However, specialized egg constituents such as yolk proteins, egg white, cholesterol, lipoproteins and egg coat substances, are formed in the liver, oviduct and perhaps in follicle cells. The assembly of the developing egg is therefore a fascinating example of division of labor among oocytes and extra‐oocyte tissues, the coordination of activities of the latter being achieved by hormones.
Genetic basis for familial amyloidotic polyneuropathy
Authors: Shimada Kazunori , Maeda Shuichiro , Araki Shukuro
Published: February 2005

Familial amyloidotic polyneuropathy (FAP) is an inherited systemic amyloidosis, characterized by the extracellular deposition of fibrillar amyloid protein, i.e. a variant type of prealbumin, and by prominent peripheral nerve involvement. We recently established the basis of FAP, using a cloned human prealbumin cDNA, restriction endonuclease(s) and Southern blot procedures. This approach clearly revealed a direct link between mutation in the prealbumin gene and FAP; individuals with FAP are heterozygous for the prealbumin gene, carrying one normal and one mutant gene. Molecular analysis of the prealbumin gene yielded pertinent data on the genetic basis for FAP.
A novel coenzymatic function of pyridoxal 5′‐phosphate
Authors: Fukui Toshio , Tagaya Mitsuo
Published: February 2005

Pyridoxal 5′‐phosphate, the vitamin B6 derivative, acts as the coenzyme of many enzymes involved in amino acid metabolism. Exceptionally, this compound was found covalently bound to glycogen phosphorylase, the key enzyme in the regulation of glycogen metabolism. Although it is essential for the function of phosphorylase, its direct role has remained an enigma. We have recently found that the glucose moiety of pyridoxal (5′)diphospho (1)‐α‐D‐glucose, a conjugate of pyridoxal 5′‐phosphate and glucose 1‐phosphate through a pyrophosphate linkage, is transferred to the nonreducing end of glycogen, forming a new α‐1,4‐glucosidic linkage. This finding emphasizes the importance of the direct phosphate‐phosphate interaction between the coenzyme and the substrate in the phosphorylase catalytic reaction. We have proposed a catalytic mechanism for phosphorylase in which the phosphate group of pyridoxal 5′‐phosphate acts as an electrophile to the phosphate group of glucose 1‐phosphate. This appears to represent the first instance of the direct involvement of a phosphate group in catalysis by enzymes.
Retroviral elements and suppressor genes in Drosophila
Authors: Parkhurst Susan M. , Corces Victor G.
Published: February 2005

The phenotype of some spontaneous mutations in Drosophila can be modified by mutations at unlinked loci. The affected alleles are caused by the insertion of retroviral transposable elements. The idiosyncratic functional and structural properties of these elements play a key role in determining the expression characteristics of the genes into which they are inserted. These phenotypes are reversed or intensified by the allelic state of suppressor and enhancer loci through changes in the transcriptional properties of the transposable elements.
Membrane contacts and lens transparency
Authors: Kistler Joerg , Bullivant Stanley
Published: February 2005

Two kinds of membrane contacts in the vertebrate lens are described. Fiber gap junctions are domains where small molecules can pass between lens cells. Membrane structures of ball‐and‐socket type interlock adjacent lens fibers and thus contribute to the structural integrity of the lens. Both of these membrane contacts appear crucial for the maintenance of lens transparency.
Slime moulds and the origin of foldback DNA
Authors: Hardman Norman
Published: February 2005

The genomes of the slime moulds are relatively small when compared with those of higher eukaryotes. They also contain far fewer families of repetitive sequences. Nevertheless, the general patterns of organization of their repetitive DNA are similar. The slime moulds can therefore help us to investigate the structure and evolution of repetitive DNA in “simple” eukaryotes and to understand how these sequences contribute to the architecture and function of the eukaryotic genome. Several questions remain, including perhaps the most important: do repetitive sequences perform some definable function?.
Rules of retinotectal mapmaking
Authors: Easter Stephen S.
Published: February 2005

The selective connections that nerve cells make to each other and to effector and receptor cells outside the nervous system are essential to organized behavior. The retinotectal projection has been used frequently in the experimental investigation of how such patterned sets of connections are formed. This article traces the evolution of some of the dominant experimental paradigms and concepts that have resulted in the currently accepted rules underlying the retinotectal map.
The use of vaccinia virus for the construction of recombinant vaccines
Authors: Piccini Antonia , Paoletti Enzo
Published: February 2005

Recombinant DNA technology has been used to engineer vaccinia virus genetically into a eukaryotic expression vector. An exciting outcome of these gene‐splicing techniques is that after the insertion of one or more genes which encode the information for antigens responsible for conferring immunity toward an infectious disease, vaccinia can be adapted for the development of live recombinant vaccines. This review discusses recombinant vaccinia design and the feasibility of using these vaccines for disease protection.
Retrovirus vectors and their uses in molecular biology
Authors: Gilboa Eli
Published: February 2005

Retroviral vectors utilize the biochemical processes unique to retroviruses, to transfer genes with high efficiency into a wide variety of cell types in tissue culture and in living animals. With such vectors, the effect of newly introduced genes and the mechanism of gene expression can be studied in cell types so far refractory to other methods of transfer.
Multifunctional polypeptides for purine de novo synthesis
Authors: Henikoff Steven
Published: February 2005

The pathway leading to the synthesis of purines for ATP, RNA, DNA and other cellular molecules involves the same enzymatic steps for all groups of organisms. However, the organization of the polypeptides catalyzing some of these steps differs strikingly from organism to organism.
Virus, toxin, complement: Common actions and their prevention by Ca2+ Or Zn2+
Authors: Pasternak Charles A.
Published: February 2005

Membrane damage induced by haemolytic agents does not necessarily lead to lysis: the pores that are formed at low concentration of agent are formed at low concentration of agent are not large enough to allow leakage of cytoplasmic proteins, and in many instances the lesions become repaired with time. Quite different agents induce a similar type of lesion: in each case leakage is reduced at low ionic strenth, and is prevented by divalent cations such as Ca2+ or Zn2+, suggesting a possible therapeutic approach to the containment of several membrane‐damaging diseases.
Regulation of expression of the c‐Myc proto‐oncogene
Authors: Marcu Kenneth B.
Published: February 2005

The c‐myc proto‐oncogene is normally subject to complex regulation at the transcriptional and post‐transcriptional levels in proliferating and differentiating cells. It is activated in response to growth stimuli and generally, though not always, repressed in response to differentiation signals. Abnormal, deregulated c‐myc expression is a common feature of numerous malignancies and occurs by a variety of molecular mechanisms which probably reflect the existence of multiple factors responsible for its normal control. Here, I provide a detailed summary of recent progress and current views on c‐myc gene regulation.
Tissue interactions in plant development
Authors: Hake Sarah
Published: February 2005

The importance of inductive phenomena in the development of new tissues and organs in animal development has long been known. Genetic experiments in plants, involving the creation of plants with distinctively marked cell populations, are now establishing the existence and importance of induction during the development of plants as well.
Molecular genetic aspects of sex determination in Drosophila
Authors: Baker Bruce S. , Nagoshi Rodney N. , Burtis Kenneth C.
Published: February 2005

Analysis of the mechanisms underlying sex determination and sex differentiation in Drosophila has provided evidence for a complex but comprehensible regulatory hierarchy governing these developmental decisions. It is suggested here that the pattern of sexual differentiation and dosage compensation characteristic of the male is a default regulatory state. Recent results have provided, in addition, some surprising and intriguing conclusions: (1) that several of the critical controlling genes produce more transcripts than was predicted from the genetic analyses; (2) that setting of the alternative sex‐specific states of the doublesex (dsx) locus involves differential transcript processing; and (3) that some aspects of sexual differentation require the prolonged action of certain elements of the regulatory hierarchy. These findings are discussed in connection with the current model of sex determination in Drosophila.
From patterns to clones in chimaeric tissues
Authors: Schmidt Günter H. , Ponder Bruce A. J.
Published: February 2005

This essay summarizes recent advances made in the analysis of mosaic patches in chimaeric epithelia of the mouse. The conclusions drawn from the observed patterns are relevant to the behaviour of expanding cell populations during tissue growth and homeostasis. References are made to clonal analysis of Drosophila.
DNA repair in man: Regulation by a multigene family and association with human disease
Authors: Cleaver James E. , Karentz Deneb
Published: February 2005

The major mechanism of repair of damage to DNA involves a conceptually simple process of enzymatic excision and resynthesis of small regions of DNA. In man and other mammals, this process is regulated by several gene loci; up to 15 mutually complementary genes or gene products may be involved. Repair deficiency results in an array of clinical symptoms in skin, central nervous system, and hematopoietic and immune systems, the major example being xeroderma pigmentosum (XP), a disease with a high incidence of cancer. Cloning repair genes by straightforward methods has proved difficult, but we have begun the effort by demonstrating that correction of a human repair deficiency can be achieved by transferring very small fragments of DNA from normal hamsters into XP cells. One of the complementation groups of XP cells (group C) appears to express a change in gene regulation such that these cells repair only a small clustered region of the DNA with high efficiency.
Nonneural microtubule proteins: Structure and function
Authors: Macrae Thomas H.
Published: February 2005

Analysis of microtubule proteins from several sources has revealed a molecular complexity consistent with the proposed multi‐functional nature of tubulin and microtubule‐associated proteins (MAP). Less certain is the actual range of functions attributable to microtubules and how the variability exhibited by the microtubule proteins translates into functional specificity. In spite of the conceptual difficulties, an exciting picture of structure/function integration is emerging from the study of microtubules.
Dengue haemorrhagic fever: Virus or host response?
Authors: Pang Tikki
Published: February 2005

The pathogenesis of dengue haemorrhagic fever has been the subject of intense research and considerable controversy. One hypothesis proposes that the immune response in a sensitized host is the primary mechanism. In contrast, others have suggested that the disease is caused by a more virulent, variant strain of dengue virus. Recent advances in molecular biology and hybridoma technology are providing valuable clues toward a solution and illustrating the fact that the course of a human viral disease is often a net result of unseparated interactions between host and virus.
Structure and function of chimaeric antibodies
Authors: Ahmed Nizamuddin
Published: February 2005

Recent techniques allow the introduction of in vitro‐manipulated immunoglobulin genes into myeloma cells to produce chimaeric antibodies. These antibodies contain the antigen‐binding variable region (V) of one species linked either to the heavy chain constant region (C) of another species or to a completely unrelated protein, such as that of certain enzymes. Apart from having novel functions and diagnostic and therapeutic applications, these antibody‐related molecules are also valuable in immunochemical studies.
Regulation of mitochondrial gene expression in Trypanosoma brucei
Authors: Stuart Kenneth D.
Published: February 2005

Trypanosoma brucei mitochondria contain unusual small circular DNAs of unknown function. These are catenated with a long informational DNA sequence containing genes homologous to those found in other mitochondria. Although these genes are transcribed throughout the life cycle, differential production of the mitochondrial respiratory system during the life cycle is accompanied by differential abundance of specific transcripts and differential polyadenylation of mitochondrial gene transcripts. Multiple transcripts occur for most of the mitochondrial genes. Transcripts of the apocytochrome b gene possessing nucleotide sequences at their 5′ ends which are not present in mitochondrial DNA are found at stages of the life cycle when the respiratory system is expressed. These results suggest the presence of post‐transcriptional mechanisms that regulate the expression of mitochondrial genes during the life cycle of T. brucei.
Antifertility factors of mammalian seminal fluid
Authors: Shivaji S. , Bhargava P. M.
Published: February 2005

The fertilizing ability of spermatozoa is inhibited by certain substances present in the seminal fluid. Most of these antifertility factors are proteinaceous in nature and differ in their physical characteristics. They inhibit fertilization by inhibiting either motility, capacitation, acrosome reaction or penetration of the ovum investments by the spermatozoa. This review describes and discusses the properties of these factors and their possible role, individually and collectively, in the regulation of fertility.
Towards a molecular understanding of differentiation mechanisms in ascidian embryos
Authors: Satoh Noriyuki
Published: February 2005

The ascidian embryo has long provided a model system for ‘mosaic’ development. This article reviews recent advances in the study of ascidian developmental biology. These include: (a) the re‐analysis of cell lineages in ascidian embryos with the ascertainment of developmental fates of every blastomere of a 110‐cell embryo; (b) the development of several tissue‐specific monoclonal antibodies; (c) the investigation and description of cell cycle requirements for differentiation; it has been found that neither cytokinesis nor nuclear division is required for differentiation, but that several rounds of DNA replication are essential for the expression of certain tissue‐specific genes; and (d) the demonstration by new descriptive and experimental studies of the presence of cytoplasmic factors or determinants responsible for specification of embryonic cell features; myoplasm which is thought to contain muscle determinants has been isolated, and immunological attempts to elucidate the molecular nature of the factors have begun.
Molecular analysis of Duchenne and Becker muscular dystrophy
Authors: Worton Ronald G.
Published: February 2005

Duchenne muscular dystrophy (DMD) is a progressive and lethal neuromuscular disorder caused by a defective gene on the X chromosome. There is no effective treatment and the biochemical defect is yet unknown. Mapping of the DMD locus to band Xp21 in the short arm of the X chromosome has given rise to strategies to clone the gene from its known location in the chromosome. Two cloning strategies have led to the isolation of a gene that is the largest of any yet described. Portions of the gene are deleted in about 8% of affected males, and rare translocations that disrupt the gene cause the disease in females. The isolation of expressed sequences from the DMD locus will undoubtedly lead to isolation of the gene product and ultimately to an understanding of the basic defect. In the meantime, DNA probes from the DMD locus provide a new and accurate approach for carrier identification and prenatal diagnosis of this dreaded disease.
The evolution of RNA viruses
Authors: Rossmann Michael G.
Published: February 2005

The structures of spherical RNA plant tiruses, containing 180 copies of one protein subunit, are closely related to those of the animal RNA picornaviruses, which are built of 60 copies of each of three larger capsid proteins. Other spherical RNA and DNA viruses utilize the same structural motif as building units of the viral capsid. It is therefore probable that many of the simple RNA viruses, whether found in animals or plants, have had a common genetic origin. The original gene may have coded for a protein that bound to specific molecules on the cell surface.
Desmutagens and bio‐antimutagens – their modes of action
Authors: Kada Tsuneo , Shimoi Kayoko
Published: February 2005

There are two ways of preventing induced cellular mutagenesis. In the first, mutagens are inactivated by ‘desmutagens’ before they can attack the DNA. In the second, ‘bio‐antimutagens’ interfere with cellular fixation processes working on damage in DNA. Examples of modes of action are shown for these inhibitors of induced mutations and implications for reducing genetic damage in man are discussed.
Metabolic mayhem caused by 2‐ketoacid imbalances
Authors: LaRossa Robert A. , Van Dyk Tina K.
Published: February 2005

A variety of herbicides act by inhibiting the branched chain amino‐acid biosynthetic enzyme, acetolactate synthase (EC 4.1.3.18). The initial consequences of this event are 2‐ketoacid accumulation and amino‐acid starvation. Recent studies demonstrate that 2‐ketoacid imbalances play a significant role in the action of these herbicides; such imbalances may also be important in certain inborn errors of human metabolism.
Regulation of non‐muscle myosin structure and function
Authors: Citi Sandra , Kendrick‐Jones John
Published: February 2005

In vertebrate and invertebrate nonmuscle myosins, light‐ and heavy‐chain phosphorylation regulate myosin assembly into filaments, and interaction with actin. Vertebrate non‐muscle myosins can exist in vitro in three main states, either ‘folded’ (assembly‐blocked) or ‘extended’ (assembly‐competent) monomers, and filaments. Light‐chain phosphorylation regulates the ‘dynamic equilibrium’ between these states. The ability of the myosin to undergo changes in conformation and state of assembly may be an important mechanism in regulating the organization of the cytoskeleton and cell motility.