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  • Springer  (66,910)
  • 1995-1999  (66,910)
  • 1970-1974
  • 1999  (66,910)
  • 101
    Electronic Resource
    Electronic Resource
    Erratum: Dev Genes Evol (1999) 209:135–144 (1999)
    Springer
    Development genes and evolution 209 (1999), S. 322-322 
    Details
    ISSN: 1432-041X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050259
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  • 102
    Electronic Resource
    Electronic Resource
    Two-color detection of mRNA transcript localizations in fish and fly embryos using alkaline phosphatase and β-galactosidase conjugated antibodies (1999)
    Springer
    Development genes and evolution 209 (1999), S. 317-321 
    Details
    ISSN: 1432-041X
    Keywords: Key words Two-color whole-mount in situ hybridization ; Anti-digoxigenin-β-galactosidase Fab fragments ; X-β-d-Gal ; Magenta-β-d-Gal ; Salmon-β-d-Gal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A fast and simplified two-color in situ hybridization procedure for the simultaneous detection of two different mRNAs in whole-mounted zebrafish and Drosophila embryos is presented. Transcript distributions are detected in a single incubation step using a mixture of alkaline phosphatase and β-galactosidase coupled antibodies. The different transcripts are visualized in contrasting colors by the use of β-galactosidase substrates that develop color precipitates (magenta, blue) easily distinguishable from those of the standard alkaline phosphatase substrates. This protocol can be followed by standard immunohistochemistry to detect the expression of a third gene (at the protein level) in a third color.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050258
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  • 103
    Electronic Resource
    Electronic Resource
    Incorporation of mouse zona pellucida proteins into the envelope of Xenopus laevis oocytes (1999)
    Springer
    Development genes and evolution 209 (1999), S. 330-339 
    Details
    ISSN: 1432-041X
    Keywords: Key words Zona pellucida ; Vitelline envelope ; Egg coat ; Mouse ; Xenopus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  All vertebrate eggs have extracellular matrices, referred to as the zona pellucida in Mus musculus and the vitelline envelope in Xenopus laevis. The mouse zona, composed of three sulfated glycoproteins (ZP1, ZP2, ZP3), is critical for fertilization and early development, and mice lacking a zona pellucida produce no live offspring. The primary structures of mouse ZP1 (623 amino acids), ZP2 (713 amino acids) and ZP3 (424 amino acids) have been deduced from full-length cDNAs, but posttranslational modifications result in mature zona proteins with molecular masses of 200–180 kDa, 140–120 kDa, and 83 kDa, respectively. The vitelline envelope forms a similar structure around Xenopus eggs and contains three glycoproteins that are structurally related (39–48% amino acid similarity) to the three mouse zona proteins. To investigate whether the structural semblances are sufficient to allow incorporation of the mouse zona proteins into the Xenopus vitelline envelope, capped synthetic mRNAs encoding ZP1, ZP2, and ZP3 proteins were injected into the cytoplasm of stage VI Xenopus oocytes. After 20 h of incubation the oocytes were harvested, and posttranslationally modified zona proteins were detected with monoclonal antibodies specific to mouse ZP1, ZP2, and ZP3. The oocytes were imaged with confocal microscopy to detect individual zona proteins in the extracellular matrix of the oocytes, and this localization was confirmed biochemically. Thus the mouse zona proteins appear to have been sufficiently conserved through 350 million years of evolution to be incorporated into the extracellular envelope surrounding Xenopus eggs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050261
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  • 104
    Electronic Resource
    Electronic Resource
    sox30: a novel zebrafish sox gene expressed in a restricted manner at the midbrain-hindbrain boundary during neurogenesis (1999)
    Springer
    Development genes and evolution 209 (1999), S. 357-362 
    Details
    ISSN: 1432-041X
    Keywords: Key words Sox ; Zebrafish ; Development ; Brain ; Midbrain-hindbrain boundary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The Sox family of proteins is thought to act to regulate gene expression in a wide variety of developmental processes. Here we describe the cloning of sox30, a novel sox gene from the zebrafish (Danio rerio). In situ hybridization shows that sox30 is expressed in a restricted manner at the boundary between the midbrain and hindbrain during nervous system development. This expression pattern is in direct contrast to that of most other neuronally expressed Sox genes which are expressed throughout the nervous system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050264
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  • 105
    Electronic Resource
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    Effects of ascorbic acid, aminoguanidine, sorbinil and zopolrestat on sorbitol and betaine contents in cultured rat renal cells (1999)
    Springer
    Experimental biology online 4 (1999), S. 1-38 
    Details
    ISSN: 1430-3418
    Keywords: Aldose reductase ; Aminoguanidine ; Ascorbic acid ; Kidney ; Sorbinil ; Sorbitol ; Zopolrestat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Aldose reductase inhibitors (ARI) have been developed to reduce the conversion of high glucose levels to sorbitol, an important renal osmolyte that may rise to damaging levels in many tissues during diabetic hyperglycemia. Ascorbic acid (AA) and aminoguanidine (AMG) have also been reported to reduce sorbitol levels in diabetes: AMG in rat kidney, and AA in guinea pig lens and human erythrocytes. We tested the effects of AMG, AA, and Pfizer’s sorbinil and zopolrestat for 48 h on primary rat renal cell cultures, established from renal inner medullas of male Wistar rats 8–12 weeks old. Osmolyte contents in scraped cells were analysed by HPLC: 100 µM sorbinil and 20 µM zopolrestat decreased sorbitol levels (P〈0.05 and P〈0.001, respectively), and increased the content of another osmolyte, betaine (P〈0.01 and 〈0.01, respectively). The quantity of ATP in cells was unchanged, suggesting no short-term problems. In contrast, 10 mM AMG and 10 mM AA had no effect on sorbitol contents (in contrast to some previous studies). We then tested aldose reductase (AR) activity in crude homogenates of rat lens and renal inner medulla, with glyceraldehyde substrate. For both tissues, 5 µM zopolrestat inhibited AR activity by 92–94% (P〈0.002); 10 mM AA by 16–20% (P〈0.02); and 10 mM aminoguanidine by 22–24% (P〈0.03). We conclude that AMG and AA are not readily usable as inhibitors of renal AR.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00898-999-0003-0
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  • 106
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    Cardio-respiratory effects of chloramine-T exposure in rainbow trout (1999)
    Springer
    Experimental biology online 4 (1999), S. 1-59 
    Details
    ISSN: 1430-3418
    Keywords: Cardiovascular physiology ; Chloramine-T ; Gas exchange ; Rainbow trout ; Respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to establish whether the blood gas respiratory disturbances noted with exposure to chloramine-T are due to differences in the rates of uptake of O2 and excretion of CO2 or gill blood flow, adult rainbow trout (Oncorhynchus mykiss) were fitted with dorsal aorta and bulbus arteriosus catheters to facilitate blood pressure recordings, an ultrasonic blood flow probe and opercular impedance electrodes. Fish received either a 45-min static exposure to 9 mg l−1 chloramine-T or tap water (control) and continuous recordings of blood pressure, and ventilation frequency and amplitude were made. Pre- and post-exposure arterial and venous blood samples were taken and analyzed for O2 and CO2 content, hemoglobin concentration and hematocrit. Chloramine-T exposure had no effect on any of the continuously recorded parameters. However, individual measurements (made immediately prior to and following exposure) of cardiac output and O2 uptake rates increased significantly following exposure to chloramine-T compared to before exposure. CO2 excretion rates were unaffected by chloramine-T exposure. Calculation of the perfusion convection requirement showed a significant increase for CO2 but not for O2. It was concluded that increases in O2 uptake resulted from increased cardiac output but that CO2 excretion, a diffusion-limited process, was not increased due to additional diffusive limitations caused by the irritant effect of chloramine-T.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00898-999-0005-y
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  • 107
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    New perspectives on the evolution of lung ventilation mechanisms in vertebrates (1999)
    Springer
    Experimental biology online 4 (1999), S. 1-28 
    Details
    ISSN: 1430-3418
    Keywords: Aspiration ; Buccal pump ; Functional morphology ; Physiology ; Respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the traditional view of vertebrate lung ventilation mechanisms, air-breathing fishes and amphibians breathe with a buccal pump, and amniotes breathe with an aspiration pump. According to this view, no extant animal exhibits a mechanism that is intermediate between buccal pumping and aspiration breathing; all lung ventilation is produced either by expansion and compression of the mouth cavity via the associated cranial and hyobranchial musculature (buccal pump), or by expansion of the thorax via axial musculature (aspiration pump). However, recent work has shown that amphibians exhibit an intermediate mechanism, in which axial muscles are used for exhalation and a buccal pump is used for inhalation. These findings indicate that aspiration breathing evolved in two steps: first, from pure buccal pumping to the use of axial musculature for exhalation and a buccal pump for inspiration; and second, to full aspiration breathing, in which axial muscles are used for both inhalation and exhalation. Furthermore, the traditional view also holds that buccal pump breathing was lost shortly after aspiration breathing evolved. This view is now being challenged by the discovery that several species of lizards use a buccal pump to augment costal aspiration during exercise. This result, combined with the observation that a behavior known as “buccal oscillation” is found in all amniotes except for mammals, suggests that a reappraisal of the role of buccal pumping in extant and extinct amniotes is in order.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00898-999-0002-1
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  • 108
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    Do lizards breathe through their mouths while running? (1999)
    Springer
    Experimental biology online 4 (1999), S. 1-46 
    Details
    ISSN: 1430-3418
    Keywords: Exercise ; Gas exchange ; Lizards ; Oronasal breathing ; Ventilation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We measured the partitioning of airflow between nasal and oral circuits in five species of lizards before, during and after exercise. Expired gases were measured separately from the mouth and nose circuits in order to estimate the relative contribution of each circuit to ventilatory airflow. Nasal breathing dominates before exercise; however, during exercise the breathing pattern switched to oronasal expiration. Airflow averaged 30% oral expiration across all species during and after exercise. These results have important implications for the design of appropriate masks for respirometry in lizards. In order to ensure that all gases are captured, it is critically important that both the nose and mouth circuits are sampled.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00898-999-0004-z
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  • 109
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    Pedagogic Interest of the H2O2, Cu2+, SCN-, OH- Oscillating Reaction (1999)
    Springer
    The chemical educator 4 (1999), S. 206-210 
    Details
    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Chemical reactivity is generally taught by considering the chemical properties of the reacting entities (acid-base, oxidation-reduction, complexation, and precipitation) and the values of the corresponding equilibrium thermodynamic constants (Ka, E0 Kd, Ks). This approach, however, is not well-suited to the dynamic chemical systems that are often encountered in industrial and environmental chemistry where nonequilibrium conditions prevail. In this respect, oscillating reactions are a good illustration of the limits of equilibrium thermodynamics and show the need for a complementary dynamic nonequilibrium study. We describe here an oscillating reaction that is easy to carry out in an inorganic chemistry practical class as it uses common reactants (H2O2, KSCN, CuSO4, NaOH). This example should enable students to obtain a more realistic grasp of chemical reactivity based on a comprehension of coupled reaction processes, similar to those encountered in population dynamics or in enzymatic regulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990336a
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  • 110
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    Qualitative Identification of an Unknown Pesticide Using GC-MS and Online Resources (1999)
    Springer
    The chemical educator 4 (1999), S. 221-225 
    Details
    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A senior-level instrumental analysis experiment is described in which students examine fruit for pesticide residues. This experiment involves fundamental instruction in sample preparation, the use of gas chromatography (GC) to resolve and deduce important components of a commercial pesticide preparation by matching against a certified standard, and unambiguous identification of the active pesticide by using mass spectrometry in conjunction with public data available on the Internet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990341a
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  • 111
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    Designing Interactive Instructional Software: Students as Educators (1999)
    Springer
    The chemical educator 4 (1999), S. 19-22 
    Details
    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This paper reviews a project conducted as part of a general chemistry course. The primary goal of the assignment was to involve our students in the process of teaching chemistry. Our work is part of STEMTEC, the Science, Technology, Engineering, and Mathematics Teacher Education Collaborative, which has been developed to improve the preparation of preservice teachers, stimulate the interest of undergraduate science and mathematics majors in the teaching profession, and increase the educational effectiveness of science and mathematics courses. The assigned project required students to create an interactive computer module that could be used to educate other students about concepts taught in general chemistry. The paper includes examples of these modules and evaluates this method of instruction. The software programs designed by the students are available for download from the Internet (http://soulcatcher.chem.umass.edu).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990277a
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  • 112
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    Atomic Variational Calculations: Hydrogen to Boron (1999)
    Springer
    The chemical educator 4 (1999), S. 40-43 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Relatively simple quantum mechanical calculations are described for atoms and ions up to boron. The calculations employ scaled hydrogenic orbitals and can be completed with or without the aid of a computer. Given the simplicity of the trial wave functions the agreement with experiment is satisfactory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990291a
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  • 113
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    Air Pollution and Health. By R. E. Hester and R. M. Harrison, Eds., Royal Society of Chemistry, Cambridge, U.K., 1998. 129 pp, 246 × 189 mm, Price £22.50, ISBN 0-85404-245-8 (1999)
    Springer
    The chemical educator 4 (1999), S. 80-80 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990294a
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  • 114
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    The History of Skunk Defensive Secretion Research (1999)
    Springer
    The chemical educator 4 (1999), S. 44-50 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The striped skunk (Mephitis mephitis) is widely known for the highly odoriferous defensive secretion it uses to repel predators. Chemists have sporadically investigated the chemical composition of this secretion for many years. In this research, a number of chemicals have been incorrectly attributed to this secretion and the errors incorporated into the chemical literature. The major component in skunk spray was erroneously believed to be l-butanethiol, until it was later shown that the actual compound was (E)-2-butene-l-thiol. More recently, two studies identified the third major compound in the secretion as either (E)-2-butenyl methyl disulfide or (E)-2-butenyl propyl sulfide. These structural assignments were incorrect and the compound was later shown to be (E)-2-butenyl thioacetate. Two investigations have reported chemicals that could not be confirmed in a later study, so these compounds may have been artifacts produced during isolation or analysis. The striped skunk’s secretion is similar to, but different from, the defensive secretions of two other skunk species, the spotted skunk (Spilogale gracilis) and the hog-nosed skunk (Conepatus mesoleucus). Folklore asserts that tomato juice will neutralize the odor of skunk spray, but human olfactory fatigue can explain the apparent disappearance of the odor on sprayed pets. The odoriferous thiols in skunk spray can easily be neutralized by oxidation to sulfonic acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990286a
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  • 115
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    The Ideal Gas Law Illustrated Using a Disposable Cigarette Lighter (1999)
    Springer
    The chemical educator 4 (1999), S. 63-64 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Three experiments are described. They illustrate the ideal gas law and cover the determination of molecular weight, the dependence of volume on the number of moles, and pressure as a function of the number of moles. A disposable lighter is used as the gas source. The experiments are suggested for use as regular laboratory exercises or as lecture demonstrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990287a
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  • 116
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    Nucleoside Chemistry and Flash Chromatography: An Integrated Approach to Teaching an Organic Chemistry Laboratory (1999)
    Springer
    The chemical educator 4 (1999), S. 65-67 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract We report here the development of an integrated approach to teaching an organic chemistry laboratory. The laboratory exercise focused on the syntheses of two modified nucleosides and used the syntheses as a vehicle to teach organic chemistry from the point of view of how science is done in the real world. The project not only taught advanced organic bench techniques, but also drew heavily from the basics of molecular biology. The laboratory exercise was taken from the work accomplished in an industrial research laboratory and introduced during the spring semester of 1998. Each three person group was provided with a file containing the relevant literature and given the task of completing the synthesis and purification in a three week period. The groups were encouraged to handle the science and chemistry in a manner similar to a research group in an industrial or academic setting. Each group presented their results in a written paper and an oral presentation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990285a
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  • 117
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    In Memoriam Glenn T. Seaborg (1912-1999): Nuclear Pioneer, Educator, and Public Servant (1999)
    Springer
    The chemical educator 4 (1999), S. 77-79 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemistry and History In this section we present articles by leading scientific historians that chronicle the important events, persons, and publications that make up the rich history of chemical science. The history of chemistry, of course, has taken place against the background of world history, and the articles in this section often make that very clear. Chemists and their research are always influenced by current events. These articles are intended to describe the setting in which important discoveries occurred and to humanize their discoverers. —Clifford LeMaster, Editor in Chief
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990290a
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  • 118
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    Programming the HP 48 Calculator to Control the Lab Works Interface (1999)
    Springer
    The chemical educator 4 (1999), S. 73-76 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract While the balanced chemical equations for a multireaction system are generally not unique, the minimum number of independent equations, R, is a characteristic property of the system. Deleting one nonspectator species from the system leads to a system with R reduced by one. In this way each system can be reduced to a single-reaction system and ultimately to a no-reaction system. The least number of chemical species that can be deleted to obtain a no-reaction system equals R. Every multireaction system, therefore, can be reduced to a number of single-reaction equations which can be balanced by any one of the standard techniques. Some examples are given where balancing by inspection is employed.
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    URL: http://dx.doi.org/10.1007/s00897990293a
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  • 119
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    Molecular Thermodynamics. By Donald A. McQuarrie and John D. Simon. (1999) University Science Books, 55D Gate Five Road, Sausalito CA 94965, USA. 672 pp $78.00, ISBN 1-891389-05-X (1999)
    Springer
    The chemical educator 4 (1999), S. 120-121 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1007/s00897990307a
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  • 120
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    Thermodynamics of Chemical Processes. By Gareth Price. Oxford University Press (1998), 86 pp (1999)
    Springer
    The chemical educator 4 (1999), S. 122-123 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990309a
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  • 121
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    ElemenTree: A 3-D Periodic Table. By Fernando Dufour available in two versions: 1. A transparent Vivak plastic periodic tree in pink, green, and black, 10-1/2 in. high, 8 in. at widest near base, US $31.00. 2. A black-and-white Mini-ElemenTree, which fits into the pocket of a 3-ring loose-leaf binder, US $18.00. Both kits include a 24-page instruction manual. Prices do not include shipping and handling or sales tax. Order as Catalog No. M2-84-0124 from Carolina Biological Supply Co., 2700 York Road, Burlington, NC 27215, Telephone: (800) 334-5551; FAX: (800) 222-7112; e-mail: dthomas@carolina.com or fcherry@carolina.com. http://www.carolina.com (1999)
    Springer
    The chemical educator 4 (1999), S. 121-122 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990308a
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  • 122
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    The Role of Multiple Teaching Strategies in Promoting Active Learning in Organic Chemistry (1999)
    Springer
    The chemical educator 4 (1999), S. 89-93 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract We have introduced four alternative teaching strategies into our yearlong organic chemistry course and have assessed changes in student performance relative to the same course taught by the same instructors using a more traditional lecture format. These strategies, which include reading worksheets, dialogues, in-class worksheets, and role-playing, allow the professor to move through a learning cycle that may effectively accommodate the students’ needs and multiple learning styles. The reading worksheets guide students through the concept phase and dialogues help students identify the importance of the concepts as they articulate these ideas for themselves. Group worksheets and role-playing provide opportunities for peer-interaction, application of knowledge, creativity, and self-expression. Others have shown that active learning strategies neither enhance nor diminish a student’s ability to retain factual information, a finding that is supported by our study. Our data from this one study show, however, that students taught by a more traditional approach demonstrate a greater variation in final exam performance between first and second semesters than those taught using a combination of techniques. This result reflects a shift in emphasis from the professor as an information source to the actively engaged student taking responsibility for his or her own learning. This study suggests that these methods, when used in a consistent fashion in conjunction with interactive lecturing, provide a broad base to facilitate student learning and aid in the development of higher order thinking skills.
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    URL: http://dx.doi.org/10.1007/s00897990297a
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  • 123
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    Synthesis and Characterization of Tris(diethyldithiocarbamato) cobalt(III) as an Undergraduate Inorganic Laboratory (1999)
    Springer
    The chemical educator 4 (1999), S. 105-107 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The synthesis of tris(diethyldithiocarbamato) cobalt(III) by the reaction of sodium diethyldithio-carbamate and cobaltous chloride is described. The recovered crystals of the cobalt complex are characterized by magnetic susceptibility, IR and NMR spectroscopy, and cyclic voltammetry.
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    URL: http://dx.doi.org/10.1007/s00897990301a
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  • 124
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    Nonlinear Regression Using the “Big Three” Spreadsheets (1999)
    Springer
    The chemical educator 4 (1999), S. 112-113 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Nonlinear regression using the spreadsheet Excel has appeared in the literature in several places. This paper extends the use of this technique to two other popular spreadsheets, Lotus 123 and Quattro Pro. Associated files, which can be downloaded, are included. These are the spreadsheet templates and ScreenCam movies that illustrate the use of equation solvers for minimization in these spreadsheets.
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    URL: http://dx.doi.org/10.1007/s00897990296a
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  • 125
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    A Fifty-Year Love Affair with Organic Chemistry. By William S. Johnson. Profiles, Pathways, and Dreams: Autobiographies of Eminent Chemists; American Chemical Society: Washington, DC, 1998. Illustrations. xxvii + 229 pp. 15.7 × 23.3 cm. $34.95. ISBN 0-8412-1834-X (1999)
    Springer
    The chemical educator 4 (1999), S. 119-120 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990302a
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    Teaching Materials that Matter: An Interactive, Multi-media Module on Zeolites in General Chemistry (1999)
    Springer
    The chemical educator 4 (1999), S. 114-118 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This paper describes a two-week teaching module, based on the structure, properties, and applications of zeolites, that was taught in a general chemistry course. We chose to focus this module on zeolite science because of the beauty and versatility of zeolites as well as their many existing and potential uses in the chemical industry. The curriculum was centered around an interactive educational computer program about zeolites that we developed specifically for the module, entitled “Zeolite Explorer.” The module also involved class lectures by faculty, a guest lecture from an industry leader, homework problems, handouts, overheads, and demonstrations. The class outline, lecture notes, handouts, overheads, homework, and “Zeolite Explorer” software are included with this article. We believe that this interactive, multimedia approach to teaching zeolite science generated more student interest in chemistry and learning an extremely important subject.
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    Equilibrium Constant Units Revisited (1999)
    Springer
    The chemical educator 4 (1999), S. 128-130 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The problem of the units associated with equilibrium constants is revisited. A brief survey of the arguments for and against using units with equilibrium constants is presented and the compromise solution that we have adopted in our teaching, both at the university and school level, is presented and justified.
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    Direct Synthesis in the Undergraduate Laboratory: Synthesis of Copper Complexes from Zero-Valent Metals as a Demonstration of Base-Catalyzed Direct Synthesis (1999)
    Springer
    The chemical educator 4 (1999), S. 131-133 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Direct synthesis is an important and active research field for scientists and technologists involved with the use of elemental metals. An undergraduate laboratory demonstration is presented that exposes students to this important synthetic technique. The direct synthesis of [Cu(NH3)4]2+ and [Cu(en)2]2+ complexes in aqueous solution from zero-valent Cu metal is employed as an experiment illustrating the oxidizing properties of alkaline hydrogen peroxide solutions. The experiment also shows the decomposition of hydrogen peroxide catalyzed by the copper complexes. Finally, students can learn that the direct oxidation of metallic copper by alkaline hydrogen peroxide solution is an efficient and novel alternative approach to synthesize these and other copper complexes.
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    Solar Energy Conversion Using a Semiconductor Electrode Photosensitized by Tetraphenylporphyrin (1999)
    Springer
    The chemical educator 4 (1999), S. 144-146 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The synthesis of meso-tetraphenylporphyrin (TPP) and its application in a solar- energy conversion device are described as an undergraduate laboratory experiment. In the first part of the exercise, a convenient procedure for the synthesis of TPP is presented. In the second section of the experiment, the construction of a high-efficiency photoelectrode that utilizes the light harvesting capacity of the porphyrin is presented. The spectral sensitization of a wide-band-gap semiconductor is achieved using TPP as an efficient photoreceptor, This mimics the role of the tetrapyrrolic macrocycle in natural photosynthesis.
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    Preparing Accurate Standard Gas Mixtures of Volatile Substances at Low Concentration Levels (1999)
    Springer
    The chemical educator 4 (1999), S. 141-143 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A simple approach for preparing standard gas mixtures of environmentally important volatile organic substances for gas chromatographic calibration is described. A liquid solution of the volatile substance of interest in a suitable solvent is prepared in a flask at known low concentration. Then, an easily measurable volume of this solution containing a very minute amount of the analyte is injected into a fixed-volume vessel (e.g., a glass sampling bulb) that has been flushed with a dilutent gas (e.g., air, N2, He). The generated gas-phase concentration of the substance after evaporation is easily calculated. This method allows students to prepare standard gas-phase mixtures at very low concentrations by direct injection of extremely small amounts into solution using a reasonable size microsyringe.
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    Upsizing: The Road to Zero Emissions. By Gunter Pauli. Greenleaf Publishing, Sheffield, UK, 1998. Softcover, 16.95 pounds sterling, 224 pp, 138 × 216 mm. ISBN 1 874719 18 7 (1999)
    Springer
    The chemical educator 4 (1999), S. 157-157 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990318a
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    Van Nostrand’s Scientific Encyclopedia. 8th Edition (software). CD-ROM, published by John Wiley. Glenn D. Considine, Douglas M. Considine and Terry G. Nash (eds.) ISBN 0-471-29323-7. $295 (1999)
    Springer
    The chemical educator 4 (1999), S. 201-201 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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    Evolutionary Design by Computers. By Peter Bentley. Academic Press: Sidcup, Kent, England. ISBN 0 1208 9040 4. Includes CD-ROM containing programs and source code. £44.94 (1999)
    Springer
    The chemical educator 4 (1999), S. 203-203 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990320a
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    An Investigation of Electrolyte Solutions Using a Simple Conductivity Apparatus (1999)
    Springer
    The chemical educator 4 (1999), S. 171-172 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A student laboratory exercise in qualitative analysis has been developed to address student misconceptions associated with electrolyte and nonelectrolyte solutions. This exercise uses a previously reported, inexpensive, home-built conductivity meter to identify acid solutions. An additional short preparatory exercise provides students the opportunity to classify known solutions as strong, weak, or nonelectrolytes and gives students experience using a conductivity meter. These activities have been used successfully with both high school and introductory college chemistry students.
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    An Alkalinity Experiment for Nonscience Majors (1999)
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    The chemical educator 4 (1999), S. 168-170 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract his article describes a simple experiment that is designed to illustrate the concepts of buffer capacity and alkalinity, while also focusing on the geological factors that influence the susceptibility of a body of water to the effects of acid rain. The students perform a semiquantitative titration of four different water samples with a dilute solution of sulfuric acid. The titrations are monitored with a pH meter. Streams flowing through regions rich in limestone have naturally high alkalinities due to the formation of bicarbonate ions from the dissolution of calcium carbonate. The focus of the experiment is to compare the buffer capacities of water samples taken from a stream that flows through a limestone-rich region with those obtained from a stream near its source at a limestone-deficient location. Students plot the pH vs. the number of drops of dilute acid added to each of the samples. The relative buffer capacities are determined from the number of drops required to reach a pH of about 4.4. Tap water and water taken from a major river that flows through central Pennsylvania were found to have fairly large buffer capacities, while deionized water and water taken from a smaller stream near its source were found to have very low buffer capacities. The results show that different bodies of water can have vastly different susceptibilities to the effects of acid rain, depending on the concentration of the bicarbonate ion. The examination of the titration curves enable students to appreciate the sudden drop in pH that occurs once all of the bicarbonate ions have been consumed.
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    Flow Injection Analysis in the Undergraduate Laboratory (1999)
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    The chemical educator 4 (1999), S. 179-182 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Flow Injection Analysis (FIA) is one of the most popular continuous-flow techniques and its versatility and simplicity can help to bring automation to teaching laboratories; however, the small number of educational papers about this technique indicates that the adoption of FIA procedures in the undergraduate curriculum has been scarce. In this work the fundamentals of FIA are presented using simple laboratory experiments. Some drawbacks that can hinder the employment of FIA by first-time users are discussed. Practical strategies to overcome these hindrances are suggested in order to facilitate the use of FIA for undergraduate laboratories.
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    TCE 2000 (1999)
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    The chemical educator 4 (1999), S. 205-205 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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    Linus Pauling on Peace: A Scientist Speaks Out on Humanism and World Survival. Selected and Edited by Barbara Marinacci and Ramesh Krishnamurthy. Rising Star Press: P.O. Box BB, Los Altos, CA, 94023, USA. Rising.Star.Press@Worldnet.ATT.net, 1998. 296 pp, 15.0 × 22.7 cm. $17.95 softcover. ISBN 0-933670-03-6 (1999)
    Springer
    The chemical educator 4 (1999), S. 198-199 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00897990332a
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    An Alternative Method of Introducing Fugacity (1999)
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    The chemical educator 4 (1999), S. 1-2 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In current textbooks fugacity is introduced according to its differential or integral mathematical formulation. In this article an alternative method of explanation is offered. It is suggested that the real state of a pure gas can be described by comparing it to a hypothetical idealized state. The differences between these two states can then be expressed in terms of a function, Φ, defined as Φ(T,P) = μreal(T,P) - μideal(T,P) where μreal and μideal are the chemical potentials of the gas in its real and ideal states, respectively. The function Φ is a molar excess quantity and is expressed as Φ(T,P) = RT1nφ where φ is the fugacity coefficient. This approach introduces fugacity deductively through the Φ function, which leads to φ, the fugacity coefficient. This method is also appropriate for introducing the activity of solution components and the fugacity of a real gas in gaseous mixtures.
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    Applications of Artificial Intelligence in Chemistry. By Hugh M. Cartwright. Oxford University Press: Oxford, England, 1993. $12.95. 92 pages. ISBN 0-19-855736-1 (1999)
    Springer
    The chemical educator 4 (1999), S. 38-38 
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    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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    Ion-Exchange Calculations Using Spreadsheets (1999)
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    The chemical educator 4 (1999), S. 231-237 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A simple set of calculations using a Microsoft Excel spreadsheet can help students determine ion-exchange equilibrium parameters, essential for the design of industrial equipment. Equilibrium parameters are evaluated from experimental isotherms obtained from different zeolites using the action-law model by means of nonlinear curve fitting (Marquardt method). Students will be able to discriminate between ideal and nonideal systems by observation of activity coefficients. The possibility of using the spreadsheet with different types of ion-exchange materials is also validated by comparing the model results with experimental data from papers available in the recent literature. Although the laboratory experience is laborious, it is very satisfactory.
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    A Computer-based, Interactive, Multimedia Software System for Teaching and Independent Student Learning of Liquid Chromatography (1999)
    Springer
    The chemical educator 4 (1999), S. 226-230 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This paper describes the design and development of an interactive, simulation-based education software system for the exploration of key concepts in liquid chromatography. Evaluation results of student use of the software will be presented. Software modules have been designed to supplement, but not replace, classroom and laboratory learning about liquid chromatography, providing students with theory, visual aids, and interactive simulations. Combined with animations and narration, the modules complement the foundation on which chromatography is taught in a general, analytical, or organic chemistry setting. Furthermore, this software allows the student to interact with the illustrated chemistry lessons, which is especially important in instances where the concepts taught transcend typical classroom material. This work serves to connect what one observes experimentally in a chromatography experiment to changing parameters such as capacity factor, number of theoretical plates, height equivalent of a theoretical plate, column length, resolution, retention time, and selectivity factor. Simulated separations are portrayed in an animated fashion as a chromatogram developing over time as a function of one or more of these variables. Finally, the software has real sample, mobile phase, column type, flow rate, and detection type options allowing the selection and simulation of solving a realistic chromatography problem. Hypothetical unknown mixtures can be separated and the sample components identified after simulating the separation of known samples.
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    Simulating the Shroud of Turin: A Laboratory Experiment (1999)
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    The chemical educator 4 (1999), S. 102-104 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The Shroud of Turin, a piece of linen cloth bearing an anatomically correct image of a crucified human being, which resembles Jesus of Nazareth, has been an enigma to scientists. While recent studies including radiocarbon dating suggest the cloth is a medieval relic, few if any proposals have been put forward that satisfactorily explain how the image was generated. In combination with a lecture on the scientific method and the problem of bias, a laboratory experiment has been developed that allows science students to attempt to simulate the image on the Shroud. The experiment involves an active-learning experience in which students discover which techniques do not work to generate the image and which begin to suggest how such an image could have been generated.
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    The Benefits of Using Web-Based Enhancements in an Environmental Chemistry Class (1999)
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    The chemical educator 4 (1999), S. 108-111 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Four semesters of student evaluations of an environmental chemistry class have been analyzed for differences that can be attributed to Web-based enhancements. The enhancements included Web-based lecture notes, reading and problem assignments, bookmark files, and videotaped lectures. We developed these materials as part of a larger project to provide university-level technical courses over the Internet. Student perceptions of the course improved significantly (α = 0.10) after adding Web-based enhancements. Student’s opinion of the instructor improved, but the change is not significant at the 90% confidence level. The student responses to “Was the course challenging?” “Was my interest stimulated?” and “Was the instructor concerned?” were unchanged in the two groups of students. Drop rates were unchanged between the two student groups. The grade-average was nearly identical for the two student groups (82.9% vs. 83.5%), but the grade-distribution changed significantly. The percentage of A’s decreased slightly when Web-based enhancements were added, but the number of B’s increased from 22% to 40%. The percentage of C’s, D’s and F’s decreased for the students with access to Web-based enhancements. These results indicate that Web-based materials helped weaker students improve their performance and, therefore, their opinion of the class and of the instructor was more favorable.
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    Biochemistry Idea Papers: Teaching Proposal Writing (1999)
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    The chemical educator 4 (1999), S. 125-127 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A biochemistry course for upper-division students builds valuable skills for students seeking industrial positions or to continue their education. Some of these skills are the abilities to think critically, read the primary literature, write coherently, and come up with new directions for research. This assignment pushes students to gain mastery on a topic of interest, develop a preliminary idea, and develop scientific writing skills. This paper describes how this complex activity can be incorporated into the undergraduate setting, using finite steps to facilitate student success.
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    Bridging the Gap Between First and Second Semester General Chemistry: A Laboratory Exercise (1999)
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    The chemical educator 4 (1999), S. 177-178 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A simple yet challenging exercise that reviews many fundamental chemical concepts and laboratory techniques from first semester general chemistry is offered for use in the first laboratory period of the second semester general chemistry course. This exercise is easy to do and involves a minimal amount of equipment and reagents. Students at the author’s school like this exercise because they get good results, yet feel challenged because they have to think for themselves.
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    Theory of Supercritical Fluid Extraction via the Discovery Approach (1999)
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    The chemical educator 4 (1999), S. 183-185 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Supercritical fluid extraction (SFE) is a technique for sample preparation that is quickly replacing Soxhlet extraction and ultrasonic extraction. This manuscript introduces two real-world applications of SFE that serve as the basis of undergraduate laboratory experiments: the analysis of caffeine in ground coffee and nicotine in cigarette tobacco. The extracts are analyzed with gas chromatography-mass spectrometry (GC-MS). The experiments are presented in a discovery fashion that enables students to develop a theoretical understanding of the role of intermolecular forces in the extraction process. The focus on theoretical aspects of SFE makes these experiments appropriate for analytical and physical chemistry labs.
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    From Triads to Catalysis: Johann Wolfgang Döbereiner (1780–1849) on the 150th Anniversary of His Death (1999)
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    The chemical educator 4 (1999), S. 186-197 
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    Topics: Chemistry and Pharmacology
    Notes: Abstract The Time: May 7, 1999. The Place: The auditorium (Döbereiner-Hörsaal) (Figure 1) of the Chemical Institute of the Friedrich-Schiller-Universität Jena, the famous German university founded in 1558, which numbered among its faculty the illustrious philosophers Johann Gottlieb Fichte, Georg Wilhelm Friedrich Hegel, and Friedrich Wilhelm Joseph von Schelling; the writer and critic Friedrich von Schlegel; and the dramatist and poet (Johann Christoph) Friedrich Schiller, whose name the university now bears [1].
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    Advanced Inorganic Chemistry, Sixth Edition. By F. Albert Cotton, Geoffrey Wilkinson, Carlos A. Murillo, and Manfred Bochmann. John Wiley & Sons, Inc.: New York, 1999. Figures, tables. xv + 1355 pp. 18.5 × 26.0 cm. $89.95, 58.50 pounds sterling. ISBN 0-471-19957-5 (1999)
    Springer
    The chemical educator 4 (1999), S. 268-270 
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    Topics: Chemistry and Pharmacology
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    Crime Scene to Court: The Essentials of Forensic Science. Edited by Peter White. The Royal Society of Chemistry: Cambridge, UK. 1998. ISBN 0-85404-539-2. Softcover, xxiv + 360 pp. Price 19.95 pounds (1999)
    Springer
    The chemical educator 4 (1999), S. 268-268 
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    Topics: Chemistry and Pharmacology
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    Beginning Group Theory for Chemistry. By Paul H Walton. Workbooks in Chemistry Series, Oxford University Press: Oxford, England. 144 pp, £16.95 (1999)
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    The chemical educator 4 (1999), S. 270-271 
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    Topics: Chemistry and Pharmacology
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    A Methodology for Constructing User-Oriented Requirements Specifications for Large-Scale Systems Using Electronic Hypermedia (1999)
    Springer
    Requirements engineering 4 (1999), S. 1-18 
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    ISSN: 1432-010X
    Keywords: Key words: Multimedia; Rapid prototyping; Requirements; specification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: requirements specifications are developed for large-scale systems, the final specification is usually an abstraction of the original requirements data into a text-based form that is often foreign to end-users. A method was developed for representing requirements through use of electronic multimedia. The resulting specification is capable of representing requirements and requirements data in a manner that is more representative of the real-world problem space than traditional specifications. This paper presents a method for incorporating multimedia exhibits, notably the results of rapid prototyping activities and animated simulation, into a requirements specification for large-scale C2I systems. To examine the effectiveness of the method, a multimedia requirements specification was developed based on an existing text specification for a real-world system. An experiment was also performed that showed the product of the methodology to be effective in increasing the understandability of the specification over that obtained from the text specification alone.
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    False Requirements Express Real Needs (1999)
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    Requirements engineering 4 (1999), S. 60-61 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Requirements Engineering for airing readers’ views on requirements engineering research and practice. Contributions that describe results, experiences, biases and research agendas in requirements engineering are particularly welcome. ‘Viewpoints’ is an opportunity for presenting technical correspondence or subjective arguments. So, whether you are a student, teacher, researcher or practitioner, get on your soapbox today and let us know what’s on your mind . . . Please submit contributions electronically to Viewpoints Editor, Bashar Nuseibeh (ban@doc.ic.ac.uk). Contributions less than 2000 words in length are preferred.
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    Seven-Layer Model of the Role of the Facilitator in Requirements Engineering (1999)
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    Requirements engineering 4 (1999), S. 38-59 
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    ISSN: 1432-010X
    Keywords: Key words: CSCW; Distributed teamwork; Facilitation; Facilitator; Groupware; Requirements capture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: There is an increasing understanding of requirements engineering as a group activity. Those who have participated in requirements workshops and meetings will recognise that success often depends on the mediation skills of the workshop facilitator. The role of the facilitator in requirements engineering was the subject of a lively debate at the International Conference on Requirements Engineering (ICRE’98) where a panel of professional facilitators 1 shared their experiences with participants. The aim of this paper is to present a full discussion of the role of the facilitator in requirements engineering. The paper is important for the following reasons: 1. The role of the facilitator in the success of requirements workshops is often grossly underestimated (if a workshop was successful, the role of the facilitator is often forgotten). 2. The requirements engineering community should develop a better understanding of the role of the facilitator in addressing the twin concerns of successfully involving people in the requirements process and of producing good-quality requirements specifications within the resources available. 3. Electronic meeting systems are increasingly being used not only in face-to-face meetings but also in meetings where participants are geographically dispersed. Detailed descriptions of the role of the facilitator will provide a blueprint for developing appropriate computer support for facilitation which may well be vital to the success of distributed requirements engineering teams. The paper discusses the importance of conflict in requirements teams and the role of the facilitator in dealing with conflict. A number of facilitated requirements methods are reviewed and a number of models of facilitation described. The paper then presents summaries of six case studies of situations where the author has acted as a professional facilitator of commercial requirements engineering teams. The lessons learned from these experiences are brought together with existing facilitation models to produce a new model. The main outcome of the research presented in this paper is a seven-layer model of the role of the facilitator.
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    URL: http://dx.doi.org/10.1007/s007660050009
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    Requirements Engineering, Soft Systems Methodology and Workforce Empowerment (1999)
    Springer
    Requirements engineering 4 (1999), S. 85-91 
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    ISSN: 1432-010X
    Keywords: Key words:Critical theory – Empowerment – Methodology – Soft systems methodology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: The fidelity and practicality of using soft systems methodology (SSM) to empower the workforce such that its members can make a fuller contribution to the requirements engineering process is critically analysed. The detailed analysis is carried out by using a (critical) philosophical approach to develop an interpretation of (some key aspects of) requirements engineering practice in actual information systems development situations, utilising a number of practical requirements engineering studies. This analysis is built upon to explain the relationship between requirements engineering, SSM and workforce empowerment. It is concluded that, by maintaining critically focused attention on the economic context, it is theoretically possible to engineer requirements for information systems that would actually empower the workforce. However, the likelihood of using SSM successfully for this purpose is low, as the economic context in which requirements engineering takes place is largely ignored by the SSM advocates.
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    URL: http://dx.doi.org/10.1007/s007660050015
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    Using Design Explanation within the Formal Object-Oriented Method (1999)
    Springer
    Requirements engineering 4 (1999), S. 152-164 
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    ISSN: 1432-010X
    Keywords: Key words:Design explanation – Design rationale – Information analysis – Requirements engineering process
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: This paper reports the results of an action research project which studied the benefits of documenting the evolution, and the rationale for the evolution, of a requirements specification. The benefits which design explanation offers designers (as documented in the literature) suggested an investigation with a view to understanding the potential contribution of the IBIS (Issue-Based Information System) approach. The paper reports an investigation into the use of ad hoc design explanation, in which design decisions were documented as they were made using the IBIS notation. This study finds both strengths and weaknesses in the approach. It reveals ways in which IBIS might be used more effectively and leads us to suggest a further study into the complementary use of ad hoc and post hoc design explanation approaches.
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    URL: http://dx.doi.org/10.1007/s007660050025
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    Information Systems Curricula Evaluated by a Method Engineering Framework (1999)
    Springer
    Requirements engineering 4 (1999), S. 210-220 
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    ISSN: 1432-010X
    Keywords: Key words:Classification – Curriculum – Information systems – Method engineering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Method engineering (ME) deals with the selection and assembly of situation-specific methods for information systems development. In this paper we use ME with a somewhat unusual perspective, that is, an educational one. We introduce a procedure for the evaluation of information systems curricula within an ME framework. Using this approach it is possible to quantitatively characterise and compare information systems curricula, showing their relative strengths and weaknesses. As an example we evaluate three model curricula (IS’90, IS’97 and ISCC’99) and analyse their differences and similarities.
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    URL: http://dx.doi.org/10.1007/s007660050021
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    Neural expression of hikaru genki protein during embryonic and larval development of Drosophila melanogaster (1999)
    Springer
    Development genes and evolution 209 (1999), S. 1-9 
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    ISSN: 1432-041X
    Keywords: Key words Synapse ; Drosophila ; Immunoglobulin superfamily ; Axonal transport ; Neurosecretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Hikaru genki (HIG) is a putative secreted protein of Drosophila that belongs to immunoglobulin and complement-binding protein superfamilies. Previous studies reported that, during pupal and adult stages, HIG protein is synthesized in subsets of neurons and appears to be secreted to the synaptic clefts of neuron-neuron synapses in the central nervous system (CNS). Here we report the analyses of distribution patterns of HIG protein at embryonic and larval stages. In embryos, HIG was mainly observed in subsets of neurons of the CNS that include pCC interneurons and RP5 motorneurons. At third instar larval stage, this protein was detected in a limited number of cells in the brain and ventral nerve cord. Among them are the motorneurons that extend their axons to make neuromuscular junctions on body wall muscle 8. Immunoelectron microscopy showed that these axonal processes as well as the neuromuscular terminals contain numerous vesicles with HIG staining, suggesting that HIG is in a pathway of secretion at this stage. Some neurosecretory cells were also found to express this protein. These data suggest that HIG functions in the nervous system through most developmental stages and may serve as a secreted signalling molecule to modulate the property of synapses or the physiology of the postsynaptic cells.
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    Distinct structural domains in the planarian brain defined by the expression of evolutionarily conserved homeobox genes (1999)
    Springer
    Development genes and evolution 209 (1999), S. 31-39 
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    ISSN: 1432-041X
    Keywords: Key words Homeobox gene ; Brain ; otd/Otx ; otp ; Planarian
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Homeobox genes such as orthodenticle in Drosophila and its mouse homologues, Otx1 and Otx2, are known to be essential for rostral brain development. To investigate the molecular basis of brain evolution, we searched for otd/Otx-related homeobox genes in the planarian Dugesia japonica, and identified two genes, DjotxA and B, whose expression appears to be restricted to the cephalic ganglion (brain). DjotxA was expressed more medially, in the region containing the termini of the visual axons, and in the visual cells, suggesting involvement in establishment of the visual system. DjotxB was expressed in a discrete region just lateral to the DjotxA-positive domain, but not in the more lateral branch structures, which in turn are characterized by the expression of Djotp, a planarian homeobox gene related to mouse Orthopedia (Otp). In transverse sections of planarians, DjotxA and B expression were observed only at the anterior ends of the stumps, corresponding to the regional pattern of the regenerating brain. Our findings suggest that the planarian brain is composed of structurally distinct and functionally diverse domains which are defined by the discrete expression of the three evolutionarily conserved homeobox genes.
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    URL: http://dx.doi.org/10.1007/s004270050224
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    Juvenile hormone modulates 20-hydroxyecdysone-inducible ecdysone receptor and ultraspiracle gene expression in the tobacco hornworm, Manduca sexta (1999)
    Springer
    Development genes and evolution 209 (1999), S. 18-30 
    Details
    ISSN: 1432-041X
    Keywords: Key words Ecdysone receptor ; Juvenile hormone ; Ultraspiracle ; Manduca
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Insect molting and metamorphosis are orchestrated by ecdysteroids with juvenile hormone (JH) preventing the actions of ecdysteroids necessary for metamorphosis. During the molt and metamorphosis of the dorsal abdominal epidermis of the tobacco hornworm, Manduca sexta, the isoforms involved in the ecdysone receptor (EcR)/Ultraspiracle (USP) complex change with the most dramatic switch being the loss of USP-1 and the appearance of USP-2 during the larval and pupal molts. We show here that this switch in USP isoforms is mediated by high 20-hydroxyecdysone (20E) and that the presence of JH is necessary for the down-regulation of USP-1 mRNA. The decrease of USP-1 mRNA in day 2 fourth instar larval epidermis in vitro required exposure to a high concentration (10–5 M) of 20E equivalent to the peak ecdysteroid concentration in vivo, whereas the increase of USP-2 mRNA occurred at lower concentrations (effective concentrations, EC50=6.3×10–7 M). During the pupal molt of allatectomized larvae which lack JH, USP-2 mRNA increased normally with the increasing ecdysteroid titer, whereas USP-1 mRNA remained high until pupation. When day 2 fifth instar larval epidermis was exposed to 500 ng/ml 20E in the absence of JH to cause pupal commitment of the cells by 24 h, USP-1 RNA remained at its high preculture level for 12 h, then increased two- to threefold by 24 h. The increase was prevented by the presence of 1 µg/ml JH I which also prevents the pupal commitment of the cells. By contrast, USP-2 mRNA increased steadily with the same EC50 as in fourth stage epidermis, irrespective of the presence or absence of JH. Under the same conditions, mRNAs for both EcR-B1 and EcR-A isoforms were up-regulated by 20E, each in its own time-dependent manner, similar to that seen in vivo. These initial mRNA increases were unaffected by the presence of JH I, but those seen after 12 h exposure to 20E were prevented by JH, indicating a difference in response between larvally and pupally committed cells. The presence of JH which maintained larval commitment of the cells also prolonged the half-life of the EcR proteins in these cells. These results indicate that both EcR and USP RNAs are regulated by 20E and can be modulated by JH in a complex manner with only that of USP-2 apparently unaffected.
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    The evolution of the hedgehog gene family in chordates: insights from amphioxus hedgehog (1999)
    Springer
    Development genes and evolution 209 (1999), S. 40-47 
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    ISSN: 1432-041X
    Keywords: Key words Hedgehog ; Asymmetry ; Floor plate ; Vertebrate evolution ; Amphioxus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The hedgehog family of intercellular signalling molecules have essential functions in patterning both Drosophila and vertebrate embryos. Drosophila has a single hedgehog gene, while vertebrates have evolved at least three types of hedgehog genes (the Sonic, Desert and Indian types) by duplication and divergence of a single ancestral gene. Vertebrate Sonic-type genes typically show conserved expression in the notochord and floor plate, while Desert- and Indian-type genes have different patterns of expression in vertebrates from different classes. To determine the ancestral role of hedgehog in vertebrates, I have characterised the hedgehog gene family in amphioxus. Amphioxus is the closest living relative of the vertebrates and develops a similar body plan, including a dorsal neural tube and notochord. A single amphioxus hedgehog gene, AmphiHh, was identified and is probably the only hedgehog family member in amphioxus, showing the duplication of hedgehog genes to be specific to the vertebrate lineage. AmphiHh expression was detected in the notochord and ventral neural tube, tissues that express Sonic-type genes in vertebrates. This shows that amphioxus probably patterns its ventral neural tube using a molecular pathway conserved with vertebrates. AmphiHh was also expressed on the left side of the pharyngeal endoderm, reminiscent of the left-sided expression of Sonic hedgehog in chick embryos which forms part of a pathway controlling left/right asymmetric development. These data show that notochord, floor plate and possibly left/right asymmetric expression are ancestral sites of hedgehog expression in vertebrates and amphioxus. In vertebrates, all these features have been retained by Sonic-type genes. This may have freed Desert-type and Indian-type hedgehog genes from selective constraint, allowing them to diverge and take on new roles in different vertebrate taxa.
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    A Caenorhabditis elegans homeobox gene expressed in the male tail, a link between pattern formation and sexual dimorphism? (1999)
    Springer
    Development genes and evolution 209 (1999), S. 59-62 
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    ISSN: 1432-041X
    Keywords: Key words Homeobox gene ; Sex determination ; Hox cluster ; ceh-7 ; egl-5
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  ceh-7 is a small Caenorhabditis elegans homeobox gene. We have shown that this gene is transcribed. Examination of the expression pattern of ceh-7 using reporter constructs revealed that it is expressed in a few cells of the male tail, which form a ring around the rectum. The most posterior member of the C. elegans Hox cluster, egl-5, an Abd-B homologue, has previously been shown to be required for the proper development of several blast cells in the male tail. We have examined the expression of ceh-7 in mutant backgrounds of egl-5 and also mab-5, an Antp/Ubx/Abd-A homologue. We find that ceh-7 is not expressed in egl-5 mutants, but is still expressed in mab-5 mutants.
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    Embryonic silk gland development in Bombyx: molecular cloning and expression of the Bombyx trachealess gene (1999)
    Springer
    Development genes and evolution 209 (1999), S. 507-514 
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    ISSN: 1432-041X
    Keywords: Key words trachealess ; Silk gland ; Trachea ; Bombyx mori
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We describe embryonic development of the Bombyx silk gland. To extend the analysis further we isolated a Bombyx counterpart gene ofthe Drosophila trachealess (trh) gene. Bombyx trh encodes a protein of 849 amino acids. When compared with the amino acid sequence of Drosophila trh, the identity of Bombyx bHLH, PAS-A and PAS-B domains is 100%, 97%, and 80%, respectively. Northern blot analysis revealed the presence of a single Bombyx trh transcript of 5.4 kb. We analyzed the expression pattern of the Bombyx trh transcript during embryogenesis by in situ hybridization. Bombyx trh mRNA was first detected in the tracheal primordial cells at around embryonic stage 18. Thereafter levels of Bombyx trh mRNA increased, and the high expression level was maintained until hatching. At embryonic stage 19 the transcript was also detected in the posterior basal region of the labial segment from where the silk gland invaginates. By the blastokinesis stage (around stage 23), the silk gland was lengthened, and, interestingly, the Bombyx trh transcript was restricted to the anterior silk gland. These results suggest that Bombyx trh plays a role in the formation of the trachea and the anterior silk glands.
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    Mouse Dach, a homologue of Drosophila dachshund, is expressed in the developing retina, brain and limbs (1999)
    Springer
    Development genes and evolution 209 (1999), S. 526-536 
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    ISSN: 1432-041X
    Keywords: Key words dachshund ; Retina ; Development ; Limb ; Brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The Drosophila genes eyeless, eyes absent, sine oculis, and dachshund cooperate as key regulators of retinal cell-fate determination. Homologues of eyeless (Pax6), eyes absent (Eya1-2), and sine oculis (Six3) have been identified and are expressed in the developing vertebrate eye. We have cloned and characterized the structure and expression of mouse Dach, a homologue of Drosophila dachshund. Sequence analysis reveals the presence of two motifs, DD1 and DD2, which may be involved in the function of Dach/Dachshund as gene regulatory factors. In addition, DD1 shares sequence similarity to N-terminal sequences of Ski and SnoN, which are involved in cellular transformation and differentiation. Mouse and human Dach/DACH were localized to chromosome 14E1 and 13q21.3–22, respectively, by fluorescence in situ hybridization. Finally, in situ hybridization analysis demonstrated that Dach is expressed in similar tissues to those observed in Drosophila, including the embryonic nervous system, sensory organs, and limbs. The finding of Dach expression in the eye completes the list of vertebrate homologues of eyeless, eyes absent, sine oculis, and dachshund which as a group may function to control cell-fate determination in the vertebrate eye.
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    ribbon, raw, and zipper have distinct functions in reshaping the Drosophila cytoskeleton (1999)
    Springer
    Development genes and evolution 209 (1999), S. 555-559 
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    ISSN: 1432-041X
    Keywords: Key words Morphogenesis ; Cell shape ; Nonmuscle myosin ; Cytoskeleton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  rib and raw mutations prevent cells in a number of tissues from assuming specialized shapes, resulting in abnormal tubular epithelia and failure of morphogenetic movements such as dorsal closure. Mutations of zip, which encodes the nonmuscle myosin heavy chain, suppress the phenotypes of rib and raw, suggesting that rib and raw are not directly required for myosin function. Abnormal formation of the actin cytoskeletal structures underlying embryonic cuticular hairs suggests possible roles for rib and raw in organizing the actin cytoskeleton. The actin prehair structures are absent in rib mutants and abnormally shaped in raw mutants, indicating that the two genes have different functions required for organizing the actin cytoskeleton.
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    Molecular cloning and expression of the human and mouse homologues of the Drosophila dachshund gene (1999)
    Springer
    Development genes and evolution 209 (1999), S. 537-545 
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    ISSN: 1432-041X
    Keywords: Key words Dachshund ; Pax6 ; Eye ; Limb ; Mammalian development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Recent genetic analysis of the Drosophila dachshund (dac) gene has established that dac encodes a novel nuclear protein that is involved in both eye and leg development. In the Drosophila eye, dac expression appears to be controlled by the product of the eyeless/Pax6 gene. In order to analyze the Pax6 pathway in vertebrates we have isolated and characterized the cDNA and genomic clones corresponding to the human and mouse homologues of Drosophila dac. A full-length human cDNA encoding dachshund (DACH) encodes the 706 amino acids protein with predicted molecular weight of 73 kDa. A 109 amino acid domain located at the N-terminus of the DACH showed significant sequence and secondary structure homologies to the ski/sno oncogene products. Northern blot analysis found human DACH predominantly in adult kidney, heart, and placenta, with less expression detected in the brain, lung, skeletal muscle and pancreas. A panel of human cell lines was studied and most notably a large proportion of neuroblastomas expressed DACH mRNA. Mouse Dach encodes a protein of 751 amino acids with predicted molecular weight of 78 kDa that is 95% identical to the human DACH. RNase protection analysis showed the highest Dach mRNA expression in the adult mouse kidney and lung, whereas lower expression was detected in the brain and testis. RT/PCR analysis readily detected Dach mRNA in the adult mouse cornea and retina. Dach mRNA expression in the mouse E11.5 embryo was observed primarily in the fore and hind limbs, as well as in the somites.
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    Expression of Xenopus T-box transcription factor, Tbx2 in Xenopus embryo (1999)
    Springer
    Development genes and evolution 209 (1999), S. 625-628 
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    ISSN: 1432-041X
    Keywords: Key words Tbx2 ; Optomotor-blind ; Xenopus ; Cement gland ; Dorsal root ganglia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We report here the cloning and expression of the Xenopus orthologue of the T-box transcription factor gene Tbx2 (optomotor-blind in Drosophila). Tbx2 is first detected in the ventral mesodermal cells just above the yolk plug at late gastrula. At the neurula stage it is strongly expressed in the cement gland, dorsal root ganglia, and otic vesicle region. At the tailbud stage strong Tbx2 expression is observed in the dorsal part of the optic cup and trigeminal ganglia, and it is also expressed in the branchial arches, heart anlage, nasal pit, proctodeum, and the region around the pronephros.
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    Immunocytochemical study on the triple origin of the sphincter iris in the chick embryo (1999)
    Springer
    Development genes and evolution 209 (1999), S. 620-624 
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    ISSN: 1432-041X
    Keywords: Key words Sphincter iris ; Chick embryo ; Iris development ; Monoclonal antibody 13F4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The ontogenic development of the sphincter iris has been studied by immunocytochemistry and standard staining on chick embryos from stage 25 HH to the time of hatching. We have used the monoclonal antibody 13F4, a highly specific marker of muscular cells. We have observed three different regions in the iris. In the pupillary region, immunoreactive cells are in continuous contact with the inner epithelium of the pupillary margin. In the intermediate region, the outer epithelium forms buds of pigmented cells that emigrate toward the stroma. In this epithelium cells that are totally or partially unpigmented exist, and they are 13F4 positive. In the sphincter we have observed 13F4 positive cells with melanin granules. In the ciliary region, the immunoreactivity appears in dispersed mesenchymal cells. The present findings are consistent with a triple origin of the sphincter iris in the chick embryo. This muscle is derived from the inner epithelium of the pupillary margin, the intermediate region of the outer epithelium, and from the mesenchymal cells. The cells of the inner epithelium of the pupillary margin are differentiated into smooth muscle cells, and the remaining cells form striated muscle cells.
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    Exon duplication from a fork head to a homeodomain protein (1999)
    Springer
    Development genes and evolution 209 (1999), S. 629-633 
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    ISSN: 1432-041X
    Keywords: Key words Exon duplication ; Homeobox gene ; Fork head gene ; Winged helix ; C. elegans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The evolution of complex organisms such as animals requires a large expansion of the number of genes controlling developmental events. In addition, it is thought that domains are shuffled between genes to further increase the complexity and generate new types of genes and functions. Working with the Caenorhabditis elegans homeobox gene ceh-43, the orthologue of fly Distal-less (Dll), we observed sequence similarity to the C. elegans gene fkh-1. Now, with the complete genomic sequence available, we examined this similarity in detail. The region of similarity is confined essentially to one exon in the carboxy terminus of the two genes. Based on the gene structure, we think that an exon of fkh-1 was duplicated to the carboxy terminus of ceh-43, where it was incorporated as the last exon. This duplication event seems to have happened recently since the similarity on the nucleotide level is higher than the sequence similarity between fkh-1 of C. elegans and C. briggsae. Potentially the duplication event was mediated via a short region of sequence similarity between the two open reading frames of the genes. This duplication event clear shows that a part of a gene can successfully be juxtaposed to another gene. These events may perhaps not be rare.
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    Segmentation gene expression in the mothmidge Clogmia albipunctata (Diptera, Psychodidae) and other primitive dipterans (1999)
    Springer
    Development genes and evolution 209 (1999), S. 145-154 
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    ISSN: 1432-041X
    Keywords: Key words hunchback ; Krüppel ; even-skipped ; Coboldia ; Megaselia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  To obtain a clearer understanding of the evolutionary transition between short- and long-germ modes of embryogenesis in insects, we studied the expression of two gap genes hunchback (hb) and Krüppel (Kr) as well as the pair-rule gene even-skipped (eve) in the dipteran Clogmia albipunctata (Nematocera, Psychodidae). This species has features of both short- and long-germ mode of embryogenesis. In Clogmia hb expression deviates from that known in Drosophila in two main respects: (1) it shows an extended dorsal domain that is linked to the large serosa anlage, and (2) it shows a terminal expression in the proctodeal region. These expression patterns are reminiscent of the hb expression pattern in the beetle Tribolium, which has a short germ mode of embryogenesis. Krüppel expression, on the other hand, was found to be rather similar to the Drosophila expression, both at early and late stages. eve expression starts with six stripes formed at blastoderm stage, while the seventh is only formed after the onset of gastrulation and germband extension. Surprisingly, no segmental secondary Eve stripes could be observed in Clogmia although such segmental stripes are known from higher dipterans, beetles and hymenopterans. We therefore also studied another nematoceran, Coboldia, to address this question and found that some segmental stripes form by intercalation as in Drosophila, although belatedly. Our results suggest that Clogmia embryogenesis, both with respect to morphological and molecular characteristics represents an intermediate between the long-germ mode known from higher dipterans such as Drosophila, and the short-germ mode found in more ancestral insects.
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    URL: http://dx.doi.org/10.1007/s004270050238
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    High conservation of cis-regulatory elements between quail and human for the Pax-6 gene (1999)
    Springer
    Development genes and evolution 209 (1999), S. 165-173 
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    ISSN: 1432-041X
    Keywords: Key words Pax-6 regulation ; Neuroretina-enhancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The Pax-6 gene encodes a transcriptional master regulator involved in the development of the eye. The quail Pax-6 gene is expressed in the neuroretina from two promoters, P0 and P1, P0 being activated at the onset of neuronal differentiation. In this paper we have identified two regions in the quail Pax-6 gene 5′ flanking sequences, located 6 and 2.5 kbp upstream from the P0 promoter that, like the previously characterised intragenic enhancer (EP enhancer), function as neuroretina-specific enhancers whose activity is restricted to the P0 promoter. Moreover, the activity of these 5′ enhancers in embryonic neuroretina cells is weaker at day 5 than at day 7, like the EP enhancer, and parallels the level of expression of P0-initiated mRNAs. Footprinting experiments show that neuroretina-specific factors bind to these 5′ enhancer elements. In addition we show that these quail Pax-6 enhancer elements, as well as the P0 promoter, are structurally and functionally conserved in humans. These results strongly suggest that these enhancer elements may contribute to the neuroretina-specific transcriptional regulation of the Pax-6 gene in vivo. Thus the complex regulation of the quail Pax-6 gene is also conserved in humans.
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    EGF signalling regulates cell invagination as well as cell migration during formation of tracheal system in Drosophila (1999)
    Springer
    Development genes and evolution 209 (1999), S. 174-179 
    Details
    ISSN: 1432-041X
    Keywords: Key words Drosophila ; Tracheal system ; Invagination ; Epidermal growth factor (EGF) signalling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The Drosophila tracheal system is a network of epithelial tubes that arises from the tracheal placodes, lateral clusters of ectodermal cells in ten embryonic segments. The cells of each cluster invaginate and subsequent formation of the tracheal tree occurs by cell migration and fusion of tracheal branches, without cell division. The combined action of the Decapentaplegic (Dpp), Epidermal growth factor (EGF) and breathless/branchless pathways are thought to be responsible for the pattern of tracheal branches. We ask how these transduction pathways regulate cell migration and we analyse the consequences on cell behaviour of the Dpp and EGF pathways. We find that rhomboid (rho) mutant embryos display defects not only in tracheal cell migration but also in tracheal cell invagination unveiling a new role for EGF signalling in the formation of the tracheal system. These results indicate that the transduction pathways that control tracheal cell migration are active in different steps of tracheal formation, beginning at invagination. We discuss how the consecutive steps of tracheal morphogenesis might affect the final branching pattern.
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    URL: http://dx.doi.org/10.1007/s004270050241
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    Cloning and expression of the engrailed.a gene of the barnacle Sacculina carcini (1999)
    Springer
    Development genes and evolution 209 (1999), S. 180-185 
    Details
    ISSN: 1432-041X
    Keywords: Key words Developmental gene ; Segmentation ; Crustacea ; Rhizocephalan cirripede
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Cirripedia (barnacles) constitute a crustacean monophyletic taxon which is very well defined by several synapomorphies. In particular, all cirripedes are composed of six thoracic segments, but are devoid of any complete abdominal segment. This body plan is preserved in the adult in non-parasitic groups, while the parasitic rhizocephalan cirripedes completely lose arthropodian segmentation at the adult stage. These traits make them a particularly favourable model for studying the formation and maintenance of segmental identity. For the above reasons, it seemed worthwhile to look at the segmentation gene engrailed in a cirripede. A complete engrailed.a cDNA was isolated from larvae of the rhizocephalan cirripede Sacculina carcini. Its expression was monitored during larval development by use of the monoclonal antibody MAb4D9 directed against the Drosophila homologous proteins. The Sacculina engrailed.a gene is expressed during the second and third larval stages in stripes within a posterior area corresponding to the presumptive trunk segments. Surprisingly, these stripes appear in a posterior to anterior sequence. Six engrailed.a stripes characterize the thoracic segments of the cirripedean ground plan.
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    URL: http://dx.doi.org/10.1007/s004270050242
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    Origin of the chordate central nervous system – and the origin of chordates (1999)
    Springer
    Development genes and evolution 209 (1999), S. 198-205 
    Details
    ISSN: 1432-041X
    Keywords: Key words Chordate ; Embryology ; Nervous system ; Phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Contrary to traditional views, molecular evidence indicates that the protostomian ventral nerve cord plus apical brain is homologous with the vertebrates’ dorsal spinal cord plus brain. The origin of the protostomian central nervous system from a larval apical organ plus longitudinal areas along the fused blastopore lips has been documented in many species. The origin of the chordate central nervous system is more enigmatic. About a century ago, Garstang proposed that the ciliary band of a dipleurula-type larva resembling an echinoderm larva should have moved dorsally and fused to form the neural tube of the ancestral chordate. This idea is in contrast to a number of morphological observations, and it is here proposed that the neural tube evolved through lateral fusion of a ventral, postoral loop of the ciliary band in a dipleurula larva; the stomodaeum should move from the ventral side via the anterior end to the dorsal side, which faces the substratum in cephalo- chordates and vertebrates. This is in accordance with the embryological observations and with the molecular data on the dorsoventral orientation. The molecular observations further indicate that the anterior part of the insect brain is homologous with the anterior parts of the vertebrate brain. This leads to the hypothesis that the two organs evolved from the same area in the latest common bilaterian ancestor, just anterior to the blastopore, with the protostome brain developing from the anterior rim of the blastopore (i.e. in front of the protostome mouth) and the chordate brain from an area in front of the blastopore, but behind the mouth (i.e. behind the deuterostome mouth).
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    URL: http://dx.doi.org/10.1007/s004270050244
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    Development of the musculature in the limpet Patella (Mollusca, Patellogastropoda) (1999)
    Springer
    Development genes and evolution 209 (1999), S. 226-238 
    Details
    ISSN: 1432-041X
    Keywords: Key words Gastropoda ; Patella ; Ontogeny ; Larval and adult muscle systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Whole-mount technique using fluorescent-labelled phalloidin for actin staining and confocal laser scanning microscopy as well as semi-thin serial sectioning, scanning and transmission electron microscopy were applied to investigate the ontogeny of the various muscular systems during larval development in the limpets Patella vulgata L. and P. caerulea L. In contrast to earlier studies, which described a single or two larval shell muscles, the pretorsional trochophore-like larva shows no less than four different muscle systems, namely the asymmetrical main head/foot larval retractor muscle, an accessory larval retractor with distinct insertion area, a circular prototroch/velar system, and a plexus-like pedal muscle system. In both Patella species only posttorsional larvae are able to retract into the shell and to close the aperture by means of the operculum. Shortly after torsion the two adult shell muscles originate independently in lateral positions, starting with two fine muscle fibres which insert at the operculum and laterally at the shell. During late larval development the main larval retractor and the accessory larval retractor become reduced and the velar muscle system is shed. In contrast, the paired adult shell muscles and the pedal muscle plexus increase in volume, and a new mantle musculature, the tentacular muscle system, and the buccal musculature arise. Because the adult shell muscles are entirely independent from the various larval muscular systems, several current hypotheses on the ontogeny and phylogeny of the early gastropod muscle system have to be reconsidered.
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    Role of a 461-bp G-rich repetitive element in H19 transgene imprinting (1999)
    Springer
    Development genes and evolution 209 (1999), S. 239-248 
    Details
    ISSN: 1432-041X
    Keywords: Key words Imprinting ; Repetitive elements ; H19 ; Transgenes ; DNA methylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The molecular mechanism leading to the imprinted expression of genes is poorly understood. While no conserved cis-acting elements have been identified within the known loci, many imprinted genes are located near directly repetitive sequence elements, suggesting that such repeats might play a role in imprinted gene expression. The maternally expressed mouse H19 gene is located approximately 1.5 kb downstream from a 461-bp G-rich repetitive element. We have used a transgenic model to investigate whether this element is essential for H19 imprinting. Previous results demonstrated that a transgene, which contains 14 kb of H19 sequence, exhibits parent-of-origin specific expression and methylation analogous to the endogenous H19 imprinting pattern. Here, we have generated transgenes lacking the G-rich repeat. One transgene, containing a deletion of the G-rich repetitive element but which includes an additional 1.7 kb of 5’H19 sequence, is imprinted similarly to the endogenous H19 gene. To determine whether the G-rich repeat is conserved in other imprinted mammalian H19 homologues, additional 5’ flanking sequences were cloned from the rat and human. This element is conserved in the rat but not in human DNA. These results suggest that the 461-bp G-rich repetitive element is not essential for H19 imprinting.
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    URL: http://dx.doi.org/10.1007/s004270050248
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    Intercalary muscle cell renewal in planarian pharynx (1999)
    Springer
    Development genes and evolution 209 (1999), S. 249-253 
    Details
    ISSN: 1432-041X
    Keywords: Key words Planarian ; Cell renewal ; Pharynx ; Muscle cells ; Myosin heavy chain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Planarian cell renewal is achieved as a result of proliferation and differentiation of totipotent undifferentiated cells called neoblasts. The absence of mitosis within the planarian pharynx raises the question as to how cell renewal and growth occur within this organ. Two explanations have been advanced: one proposes that new cells remain close to the base of the pharynx, which then grows by distal displacement of older cells, and the other suggests that the new cells are intercalated between older cells throughout the pharynx. The second alternative, however, does not explain how new cells enter the pharynx or how they reach their final destination. In this study of myosin heavy-chain gene expression within planarian pharynx, a row of differentiating myocytes was detected all along the pharynx parenchyma. According to the hybridization pattern, all these myocytes appeared to be at early stages of differentiation. These data favour an intercalary model for muscle cell renewal within the pharynx. According to this model, neoblasts at the base of the pharynx would enter the pharynx, where they would start differentiation to myocytes, move to the subepithelial musculature and intercalate between the old muscle cells. The possible application of this intercalary model to other pharynx cell types is also discussed.
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    An amphioxus Msx gene expressed predominantly in the dorsal neural tube (1999)
    Springer
    Development genes and evolution 209 (1999), S. 260-263 
    Details
    ISSN: 1432-041X
    Keywords: Key words Amphioxus ; Msx gene ; Neural crest ; Placodes ; Vertebrate evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Genomic and cDNA clones of an Msx class homeobox gene were isolated from amphioxus (Branchiostoma floridae). The gene, AmphiMsx, is expressed in the neural plate from late gastrulation; in later embryos it is expressed in dorsal cells of the neural tube, excluding anterior and posterior regions, in an irregular reiterated pattern. There is transient expression in dorsal cells within somites, reminiscent of migrating neural crest cells of vertebrates. In larvae, mRNA is detected in two patches of anterior ectoderm proposed to be placodes. Evolutionary analyses show there is little phylogenetic information in Msx protein sequences; however, it is likely that duplication of Msx genes occurred in the vertebrate lineage.
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    Sequence and developmental expression of amphioxus AmphiNk2–1: insights into the evolutionary origin of the vertebrate thyroid gland and forebrain (1999)
    Springer
    Development genes and evolution 209 (1999), S. 254-259 
    Details
    ISSN: 1432-041X
    Keywords: Key words NK2 homeobox ; Cephalochordata ; Lancelet ; Diencephalon ; Endostyle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We characterized an amphioxus NK-2 homeobox gene (AmphiNk2–1), a homologue of vertebrate Nkx2–1, which is involved in the development of the central nervous system and thyroid gland. At the early neurula stage of amphioxus, AmphiNk2–1 expression is first detected medially in the neural plate. By the mid-neurula stage, expression is localized ventrally in the nerve cord and also begins in the endoderm. During the late neurula stage, the ventral neural expression becomes transiently segmented posteriorly and is then down-regulated except in the cerebral vesicle at the anterior end of the central nervous system. Within the cerebral vesicle AmphiNk2–1 is expressed in a broad ventral domain, probably comprising both the floor plate and basal plate regions; this pattern is comparable to Nkx2–1 expression in the mouse diencephalon. In the anterior part of the gut, expression becomes intense in the endostyle (the right wall of the pharynx), which is the presumed homologue of the vertebrate thyroid gland. More posteriorly, there is transitory expression in the midgut and hindgut. In sum, the present results help to support homologies (1) between the amphioxus endostyle and the vertebrate thyroid gland and (2) between the amphioxus cerebral vesicle and the vertebrate diencephalic forebrain.
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    Hormonal control of ventral diaphragm myogenesis during metamorphosis of the moth, Manduca sexta (1999)
    Springer
    Development genes and evolution 209 (1999), S. 265-274 
    Details
    ISSN: 1432-041X
    Keywords: Key words Myogenesis ; Ecdysteroid ; Juvenile hormone ; Cell cycle ; Manduca sexta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Both the proliferation and differentiation of ventral diaphragm myoblasts are controlled by ecdysteroid during metamorphosis of the moth, Manduca sexta, but the responses have different hormonal requirements. Tonic exposure to moderate levels of ecdysteroid are required to stimulate myoblast proliferation. This is due to the presence of an ecdysteroid-dependent control point in the G2 phase of the cell cycle. As a result, proliferation can be repeatedly turned on or off simply by adjusting the concentration of ecdysteroid to be above or below a critical threshold concentration. In contrast, high levels of ecdysteroid trigger irreversible proliferative arrest and differentiation of myofibers. Myoblast proliferation and differentiation also differ in their response to the juvenile hormone mimic, methoprene. Ecdysteroid-dependent proliferative arrest and differentiation are blocked by coculture with methoprene but methoprene has no effect on ecdysteroid-dependent proliferation. In the animal, premature exposure to high levels of ecdysteroid in the absence of juvenile hormone triggers precocious differentiation of the myoblasts, resulting in the formation of several thin bands of muscle rather than a complete diaphragm. Thus, ecdysteroid and juvenile hormone collaborate to determine the size and shape of the adult musculature.
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    Maternal factors and the evolution of developmental mode: Evolution of oogenesis in Heliocidaris erythrogramma (1999)
    Springer
    Development genes and evolution 209 (1999), S. 275-283 
    Details
    ISSN: 1432-041X
    Keywords: Key words Echinoid ; Oogenesis ; Development ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Evolutionary change in developmental mode in sea urchins is closely tied to an increase in maternal provisioning. We examined the oogenic modifications involved in production of a large egg by comparison of oogenesis in congeneric sea urchins with markedly different sized oocytes and divergent modes of development. Heliocidaris tuberculata has small eggs (95 µm diameter) and the ancestral mode of development through feeding larvae, whereas H. erythrogramma has large eggs (430 µm diameter) and highly modified non-feeding lecithotrophic larvae. Production of a large egg in H. erythrogramma involved both conserved and divergent mechanisms. The pattern and level of vitellogenin gene expression is similar in the two species. Vitellogenin processing is also similar with the gonads of both species incorporating yolk protein from coelomic and hemal stores into nutritive cells with subsequent transfer of this protein into yolk granules in the developing vitellogenic oocyte. Immunocytology of the eggs of both Heliocidaris species indicates they incorporate similar levels of yolk protein. However, H. erythrogramma has evolved a highly divergent second phase of oogenesis characterised by massive deposition of non-vitellogenic material including additional maternal protein and lipid. Maternal provisioning in H. erythrogramma exhibits recapitulation of the ancestral vitellogenic program followed by a novel oogenic phase with hypertrophy of the lipogenic program being a major contributor to the increase in egg size.
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    The production and elimination of supernumerary blast cells in the leech embryo (1999)
    Springer
    Development genes and evolution 209 (1999), S. 284-293 
    Details
    ISSN: 1432-041X
    Keywords: Key words Annelid ; Leech ; Segmentation ; Cell death ; Lineage tracer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Different species of leech vary greatly in body size but all have 32 body segments. It is unclear how the development of this precise number of segments is regulated, although it is known that the teloblasts of the early leech embryo initially produce more than the required numbers of segment founder cells (blast cells). We used fluorescent dextrans to show that the M teloblast of the Helobdella robusta embryo produces a variable number of additional (supernumerary) cells. These cells fail to enter the germinal band (which contains cells of all lineages and gives rise to the adult leech), but detach from its posterior end and disappear. Our observations suggest that some suffer an increase in membrane permeability while others fuse with the M teloblasts, but that they do not undergo apoptosis. The supernumerary cells of different lineages detach from the germinal band at different times, suggesting that detachment is not triggered by a global signal acting simultaneously on all lineages. We tested the hypothesis that the elimination of the supernumerary m blast cells results from a requirement of m blast cells for close interactions with cells of the other lineages for their survival, a condition that would not be achieved by the last-born m blast cells that fail to enter the germinal band. We cultured isolated M teloblasts and found that they do produce blast cells that themselves divide, indicating that cells of the M lineage can survive in the absence of any interactions with cells of the other lineages.
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    The Suppressor of fused gene, involved in Hedgehog signal transduction in Drosophila, is conserved in mammals (1999)
    Springer
    Development genes and evolution 209 (1999), S. 294-300 
    Details
    ISSN: 1432-041X
    Keywords: Key words Evolution ; Suppressor of fused ; Hedgehog ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The Suppressor of fused [Su(fu)] gene of Drosophila melanogaster encodes a protein containing a PEST sequence [sequence enriched in proline (P), glutamic acid (E), serine (S) and threonine (T)] which acts as an antagonist to the serine-threonine kinase Fused in Hedgehog (Hh) signal transduction during embryogenesis. The Su(fu) gene isolated from a distantly related Drosophila species, D. virilis, shows significantly high homology throughout its protein sequence with its D. melanogaster counterpart. We show that these two Drosophila homologs of Su(fu) are functionally interchangeable in enhancing the fused phenotype. We have also isolated mammalian homologs of Su(fu). The absence of the PEST sequence in the mammalian Su(fu) protein suggests a different regulation for this product between fly and vertebrates. Using the yeast two-hybrid method, we show that the murine Su(fu) protein can interact directly with the Fused and Cubitus interruptus proteins, known partners of Su(fu) in Drosophila. These data are discussed in the light of their evolutionary relationships.
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    The role of wingless in the development of multibranched crustacean limbs (1999)
    Springer
    Development genes and evolution 209 (1999), S. 340-348 
    Details
    ISSN: 1432-041X
    Keywords: Key words Limb development ; Crustacean ; Wingless
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Arthropods are the most diverse and speciose group of organisms on earth. A key feature in their successful radiation is the ease with which various appendages become readily adapted to new functions in novel environments. Arthropod limbs differ radically in form and function, from unbranched walking legs to multibranched swimming paddles. To uncover the developmental and genetic mechanisms underlying this diversification in form, we ask whether a three-signal model of limb growth based on Drosophila experiments is used in the development of arthropod limbs with variant shape. We cloned a Wnt-1 ortholog (Tlwnt-1) from Triops longicaudatus, a basal crustacean with a multibranched limb. We examined the mRNA in situ hybridization pattern during larval development to determine whether changes in wg expression are correlated with innovation in limb form. During larval growth and segmentation Tlwnt-1 is expressed in a segmentally reiterated pattern in the trunk. Unexpectedly, this pattern is restricted to the ventral portion of the epidermis. During early limb formation the single continuous stripe of Tlwnt-1 expression in each segment becomes ventrolaterally restricted into a series of shorter stripes. Some but not all of these shorter stripes correspond to what becomes the ventral side of a developing limb branch. We conclude that the Drosophila model of limb development cannot explain all types of arthropod proximodistal outgrowths, and that the multibranched limb of Triops develops from an early reorganization of the ventral body wall. In Triops, Tlwnt-1 plays a semiconservative role similar to that played by Drosophila wingless in segmentation and limb formation, and morphological innovation in limb form arises in part through an early modulation in the expression of the Tlwnt-1 gene.
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    Neurogenesis during caudal spinal cord regeneration in adult newts (1999)
    Springer
    Development genes and evolution 209 (1999), S. 363-369 
    Details
    ISSN: 1432-041X
    Keywords: Key words Spinal cord ; Regeneration ; Amphibian urodeles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  After tail amputation in urodele amphibians, dramatic changes appear in the spinal cord rostral to the amputation level. Transection induces a proliferation response in cells lining the ependymal canal, giving rise to an ependymal tube in which neurogenesis occurs. Using the thymidine analog bromodeoxyuridine (BrdU) in short- and long-term labeling of cells undergoing DNA synthesis (S phase of the cell cycle), specific cell markers, and cell cultures, we show that neurons derive from the proliferative ependymal layer of the ependymal tube.
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    Genetic analysis of steel and the PG-M/versican-encoding gene AxPG as candidates for the white (d) pigmentation mutant in the salamander Ambystoma mexicanum (1999)
    Springer
    Development genes and evolution 209 (1999), S. 349-356 
    Details
    ISSN: 1432-041X
    Keywords: Key words Pigment cell ; Growth factor ; Extracellular matrix ; Neural crest ; Proteoglycan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Vertebrate non-retinal pigment cells are derived from neural crest (NC) cells, and several mutations have been identified in the Mexican axolotl Ambystoma mexicanum (Ambystomatidae) that affect the development of these cell lineages. In ”white” (d) mutant axolotls, premigratory NC cells differentiate as pigment cells, yet fail to disperse, survive, or both, and this leads to a nearly complete absence of pigment cells in the skin. Previous studies revealed that d affects pigment cell development non-autonomously, and have reported differences between white and wild-type axolotls in the structure and composition of the extracellular matrix through which NC and pigment cells migrate. Here we test the correspondence of d and two candidate genes: steel and AxPG. In amniotes, Steel encodes the cytokine Steel factor (mast cell growth factor; stem cell factor; kit ligand), which is expressed along the migratory pathways of melanocyte precursors and is required by these cells for their migration and survival; mammalian Steel mutants resemble white mutant axolotls in having a deficit or complete absence of pigment cells. In contrast, AxPG encodes aPG-M/versican-like proteoglycan that may promote the migration of A. mexicanum pigment cells, and AxPGexpression is reduced in white mutant axolotls. We cloned a salamander orthologue of steel and used a partial genetic linkage map of Ambystoma to determine the genomic locations of steel, AxPG, and d. We show that the three genes map to different linkage groups, excluding steel and AxPG as candidates for d.
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    A system to efficiently maintain embryonic lethal mutations in the flour beetle Tribolium castaneum (1999)
    Springer
    Development genes and evolution 209 (1999), S. 382-389 
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    ISSN: 1432-041X
    Keywords: Key words Tribolium castaneum ; Lethal mutants ; Stockkeeping ; Block system ; Egg collection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Due to its small size, short life cycle, and easy maintenance, the flour beetle Tribolium castaneum is well suited for the genetic analysis of development. One drawback of Tribolium as a genetic system is, however, the difficulty of keeping embryonic lethal lines. Presently, only few lethal mutations can be kept as balanced stocks. Therefore, heterozygous carriers must be identified anew in every generation in order to maintain a recessive embryonic mutation. To alleviate this problem we have devised a block system that allows the simultaneous processing of many mutant lines or test crosses for visual inspection of larval cuticle phenotypes. Using this technique, one person can maintain about 100 embryonic lethal stocks, which makes feasible the thorough genetic analysis of embryogenesis in this species.
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    George C. Pimentel (1922–1989): A Retrospective Personal and Pictorial Tribute a Decade after His Death (1999)
    Springer
    The chemical educator 4 (1999), S. 242-258 
    Details
    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Ever since receiving the 1993 ACS Pimentel Award in Chemical Education (Figure 1), I have been interested in the life and achievements of the Fresno-born, larger-than-life figure after whom the award was named. The year 1999 provides an especially appropriate occasion to recall Pimentel’s personal and professional career, for it is the tenth anniversary not only of his death but also of National Chemistry Week, the expanded form of National Chemistry Day, the popular American Chemical Society outreach program that he originated.
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    Ectopic mesodermal expression promoted by the eight-cell stage Bufo arenarum subequatorial cytoplasm (1999)
    Springer
    Development genes and evolution 209 (1999), S. 421-426 
    Details
    ISSN: 1432-041X
    Keywords: Key words Mesoderm in amphibians ; Cytoplasmic determinants ; Localization phenomenon ; Cytoplasmic transfer ; Marginal zone cytoplasm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Mesodermal determinants were investigated by cytoplasmic transfer and blastomere isolation in the eight-cell stage of Bufo arenarum. Their existence was confirmed by assaying the subequatorial cytoplasm’s ability to respecify the developmental potency of animal quartets. The gray subequatorial cytoplasm, but not animal cytoplasm, is able to divert the ectodermal fate of animal quartets to several mesodermal components. The source of the transplanted cytoplasm was important in determining the category of the resulting structures. Ventral subequatorial cytoplasm from ventrovegetal blastomeres generated ventral derivatives, namely erythrocytes and mesenchyma. Dorsal subequatorial cytoplasm from dorsovegetal blastomeres produced dorsolateral derivatives, such as notochord, muscle, nephric tubules, and coelomic epithelium, including mesenchyma. On the other hand, transfer of vegetal pole cytoplasm to animal quartets resulted in the formation of groups of endoderm-like cells dispersed among epidermal cells. However, the presence of such cells did not cause any mesodermal induction. The present findings suggest the existence of cytoplasmic information responsible for mesodermal specification. The alternative hypothesis that animal blastomeres become mesoderm due to vegetal induction is questioned.
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    Expression of MADS box genes ZMM8 and ZMM14 during inflorescence development of Zea mays discriminates between the upper and the lower floret of each spikelet (1999)
    Springer
    Development genes and evolution 209 (1999), S. 411-420 
    Details
    ISSN: 1432-041X
    Keywords: Key words Flower development ; Floral determinacy ; Spikelet ; MADS box genes ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Most floral meristem and organ identity genes of dicotyledonous plants belong to the MADS box gene family. Since they are generally transcribed in those tissues and organs whose identity they determine, they are excellent markers for developmental processes. Here we report the cDNA cloning of a pair of MADS box genes, ZMM8 and ZMM14, from the monocotyledonous plant maize. Maize inflorescences are composed of spikelets which contain two florets, an upper and a lower one. Although upper and lower florets develop in a very similar way in male inflorescences, ZMM8 and ZMM14 expression was found in all organs of upper florets, but no transcripts were detected in lower florets. In contrast, two other MADS box genes were found to be expressed in lower florets in the same way as in upper florets. Our observations suggest that during spikelet development ZMM8 and ZMM14 work as selector genes which are involved in distinguishing the upper from the lower floret. Alternatively, these genes may be involved in conferring determinacy to the spikelet or upper floret meristem. Our data suggest that in the phylogenetic lineage that led to maize an ancient type of MADS box gene has been recruited during evolution for the establishment of novel positional information not found within the simple inflorescences of dicotyledonous plants such as Arabidopsis.
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    URL: http://dx.doi.org/10.1007/s004270050271
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    Tissue-specific requirements for a phosphorylation site in the Fushi tarazu homeodomain (1999)
    Springer
    Development genes and evolution 209 (1999), S. 427-431 
    Details
    ISSN: 1432-041X
    Keywords: Key words Drosophila ; Fushi tarazu ; Homeodomain ; Phosphorylation ; Neurogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The homeodomain protein Fushi tarazu (Ftz) is required for several embryonic patterning processes including segmentation and neurogenesis. During the stages that these processes are regulated the protein is differentially phosphorylated, suggesting that phosphorylation plays a role in helping the protein to regulate different functions in different tissues. We showed in a recent study that one of the Ftz phosphorylation sites, a protein kinase A-type site in the N-terminal arm of the homeodomain, is required for normal Ftz-dependent segmentation. Here we test whether phosphorylation of this site (Thr-263) is also required in the developing central nervous system (CNS). A well-established role for Ftz in the CNS is for the differentiation of neurons referred to as RP2 neurons. Absence of Ftz expression in these cells causes a failure of certain target genes to be expressed and subsequent defects in RP2 differentiation. In contrast to its effect on segmentation, we find that mutation of Thr-263 to Ala (or Asp) has no effect on these CNS functions. This suggests that the phosphorylation state of this site is irrelevant for Ftz function in the CNS, and that there are tissue-specific differences in the requirements for Ftz phosphorylation.
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    URL: http://dx.doi.org/10.1007/s004270050273
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    Differential expression of two nonallelic MyoD genes in developing and adult myotomal musculature of the trout (Oncorhynchus mykiss) (1999)
    Springer
    Development genes and evolution 209 (1999), S. 432-437 
    Details
    ISSN: 1432-041X
    Keywords: Key words MyoD genes ; Myogenin ; Gene duplication ; Trout ; In situ hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Previously we identified two nonallelic MyoD encoding genes in the rainbow trout. These two MyoD genes (TMyoD and TMyoD2) were duplicated during the tetraploidization of the salmonid genome. In this study we show that TMyoD and TMyoD2 exhibit a distinct spatiotemporal pattern of expression that defines discrete cell populations in the developing somite. TMyoD expression is first detected in the mid-gastrula on either side of the elongating embryonic shield. During the anterior-to-posterior wave of somite formation the TMyoD transcript is initially present in adaxial cells of both the presomitic mesoderm and the forming somites. A lateral extension of TMyoD expression occurs only when the myotomes acquire their characteristic chevron shape pointing rostrally. By contrast, the initial expression of TMyoD2 occurs in somites that have already formed and is limited to the posterior compartment of somites. Further, in postlarval trout we observed a differential expression of TMyoD and TMyoD2 genes in muscle fibers with differing phenotype. Collectively, these data provide evidence that the two trout MyoD encoding genes have evolved to become functionally different. A comparison of the expression patterns of the two trout MyoD genes with that of myogenin allowed us to position them in the regulatory pathway leading to muscle differentiation.
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    URL: http://dx.doi.org/10.1007/s004270050274
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    Differential response of fetal and neonatal myoblasts to topographical guidance cues in vitro (1999)
    Springer
    Development genes and evolution 209 (1999), S. 438-442 
    Details
    ISSN: 1432-041X
    Keywords: Key words Contact guidance ; Grooved topography ; Myoblasts ; Myogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Fusion of mononucleated myoblasts into parallel arrays of mutinucleated myotubes is an essential step in skeletal myogenesis. The formation of such a highly ordered structure requires myoblasts to come together, orient and align in the correct location prior to fusion. We report here that fetal and neonatal myoblasts can use topographical features as strong guidance cues in vitro. Myoblasts were cultured on multiple grooved substrata of varying dimensions, and the axial orientations of individual cells were recorded. Both fetal and neonatal myoblasts aligned parallel with the direction of deep grooves (2.3–6.0 µm), which is correlated well with the location of myoblasts in similar sized grooves during secondary myogenesis. Fetal myoblasts also responded to shallower grooves (0.04–0.14 µm) by aligning parallel or perpendicular to the direction of the grooves, indicating the ability of these cells to respond to fine elements normally encountered within the developing muscle architecture. In contrast, neonatal myoblasts failed to respond to shallow grooves, adding to the suggestion that fetal and neonatal myoblasts may represent separate populations of myoblasts. Overall, the results demonstrate that myoblasts respond to large and small features of the physical topography in vitro and indicate that structural elements in the microenvironment of the muscle may play a critical role in myoblast spatial organization during myogenesis.
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    URL: http://dx.doi.org/10.1007/s004270050275
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    Zebrafish CTH1, a C3H zinc finger protein, is expressed in ovarian oocytes and embryos (1999)
    Springer
    Development genes and evolution 209 (1999), S. 443-446 
    Details
    ISSN: 1432-041X
    Keywords: Key words C3H ; Zinc finger protein ; Zebrafish ; Oocyte maturation ; Maternal genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The Zfcth1 gene is, as the previously cloned carp cth1 gene, related to the mammalian TIS 11 family of primary response genes and encodes a protein with two putative CCCH zinc fingers. This report describes the RNA expression of this gene during oogenesis and early embryogenesis up to gastrulation in the zebrafish (Danio rerio). Maternal cth1 message is present in the ovary of 1-month-old fish and of adult fish in oocytes at all stages of maturation. In the youngest oocytes the message is localized in the cytoplasm all around the nucleus, in larger oocytes the message becomes restricted to the future animal pole of the embryo, and in mature oocytes the expression is sharply localized in the cortical layer under the micropyle. After ovulation the cth1 messenger spreads over the cytoplasmic cap and is distributed over the blastomeres during subsequent cleavages. In subsequent stages maternal expression of cth1 gradually disappears. From early epiboly stages onward embryonic cth1 expression is localized to the germ ring and the hypoblast cells in the central part of the embryonic shield. In the shield, cth1 expression largely overlaps with the area of gooscoid expression in the first involuting cells. In stages after 70% of epiboly cth1 expression diminishes and soon can no longer be detected in the embryo. Next to a developmental role in cell fate determination we propose a function for cth1 during oocyte maturation.
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    URL: http://dx.doi.org/10.1007/s004270050276
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    Gene transfer into insect brain and cell-specific expression of bombyxin gene (1999)
    Springer
    Development genes and evolution 209 (1999), S. 447-450 
    Details
    ISSN: 1432-041X
    Keywords: Key words Bombyxin ; Insulin ; Bombyx mori ; Electroporation ; Cell-specific expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A transgene reporter consisting of the bombyxin gene promoter and the green fluorescent protein coding region was introduced into intact brains of the silkworm Bombyx mori by in vitro electroporation. After in vitro culture of the brains, the fluorescence derived from the introduced reporter gene was observed in all cases in eight neurosecretory cells that had previously been identified as bombyxin-producing cells (BPCs). Although the fluorescence was not always observed in all cells, it was specific to BPCs, indicating that the reporter was under the control of the bombyxin gene promoter in a BPC-specific manner. Electroporatical introduction of a reporter gene was therefore found to be a suitable method for analyzing cell-specific expression in intact tissues and to be substitute for germ-line transmission of reporters in the transgenic system. Application of this technique enables us to analyze the cell-specific expression of transgene reporters within a few days and treat more than several dozens of the reporters within 1 month, which is difficult to do with the transgenic system.
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    URL: http://dx.doi.org/10.1007/s004270050277
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    Vulva formation in Pristionchus pacificus relies on continuous gonadal induction (1999)
    Springer
    Development genes and evolution 209 (1999), S. 451-459 
    Details
    ISSN: 1432-041X
    Keywords: Key words Pristionchus pacificus ; Vulva ; Induction ; Caenorhabditis elegans ; Evolution and development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  One of the best known features of vulva development in Caenorhabditis elegans is the induction of vulval precursor cells by the gonadal anchor cell. Induction is crucial for the initiation of pattern formation within the C. elegans vulva equivalence group, and it is therefore surprising to find that this aspect of vulva formation, in particular, varies greatly among nematodes. In some species which form vulvae in the posterior body region, no gonadal signal is necessary for vulva induction. In other nematodes, such as Panagrolaimus, Oscheius, and Rhabditella, vulva formation depends on two temporally distinct gonadal inductions which specify the different cell fates. Here we report our analysis of vulva induction in Pristionchus pacificus, a specieswhich has recently been used as a genetic system to analyze the evolution of vulva development. Cell ablation studies in P. pacificus show that another mode of vulva induction exists. P. pacificus vulva formation depends on a continuous gonadal induction that starts several hours after hatching and continues until the birth of the anchor cell, some 20 h later. Mutations defective in gonadal induction result in the absence of vulva differentiation, suggesting that only one signaling system is involved in the gonadal-epidermal interaction. This new mode adds further to the great variety of gonadal inductions among nematode species.
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    URL: http://dx.doi.org/10.1007/s004270050278
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    Homeotic gene expression in the wild-type and a homeotic mutant of the moth Manduca sexta (1999)
    Springer
    Development genes and evolution 209 (1999), S. 460-472 
    Details
    ISSN: 1432-041X
    Keywords: Key words Insect ; Development ; Homeotic mutant ; Appendage ; Spiracle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Antibodies were used to examine the expression patterns of Antennapedia (Antp), Ultrabithorax (Ubx), Ubx and abdominal-A combined(Ubx/abd-A),and Distalless (Dll) in the embryos of the moth Manduca sexta. We found that the spatial and temporal pattern of Antp expression in Manduca was correlated with the anterior migration of two patches of epithelium that include the anterior-most tracheal pits, and with the development of functional spiracles. Ubx expression showed an intricate pattern which suggests complex regulation during development. Throughout Manduca embryogenesis the expression of Ubx/Abd-A and Dll was similar to that reported for other insects. However, there was no apparent reduction in Ubx/Abd-A expression in the Manduca abdominal proleg primordia that expressed Dll. The expression of these four proteins was also examined in embryosof the Manduca homozygous homeotic mutant Octopod (Octo). The Octo mutation results in the transformation of A1 and A2 in the anterior direction, with homeotic legs appearing on A1 and occasionally A2. Our results suggest that in Octo animals there is a reduction in the level of Ubx protein expression throughout its domain. Based on homeotic gene expression in wild-type and mutant Manduca and in other insects, we discuss potential roles of homeotic genes in insect morphological evolution.
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    URL: http://dx.doi.org/10.1007/s004270050279
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    Axial variation in the threespine stickleback: relationship to Hox gene expression (1999)
    Springer
    Development genes and evolution 209 (1999), S. 473-481 
    Details
    ISSN: 1432-041X
    Keywords: Key words Hox genes ; Hox code ; Variation ; Gasterosteus aculeatus ; Axial skeleton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Despite mounting evidence that key developmental regulator genes are involved in significant macroevolutionary changes, there have been few studies demonstrating the functional significance of variation in such genes for the generation of population-level variation. In this study we examined and compared the expression domains of three Hox gene homeobox sequences in embryos derived from two morphologically distinct populations of the threespine stickleback, Gasterosteus aculeatus. We found within-population variation in the location of anterior limits, particularly in more 5’Hox genes whose anterior expression domains showed graded distributions of transcripts over several somites. However, despite considerable and statistically significant differences in the anteroposterior pattern of the axial and median skeletons between the two stickleback populations, this phenotypic variation was not found to be correlated with any of the variation in Hox gene expression. The possible functional significance of the combinatorial Hox code in fish species is discussed with respect to the buffering of development in fluctuating environments, and it is argued that population and quantitative genetic perspectives should also be taken into account in considering the function and evolution of Hox genes.
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    URL: http://dx.doi.org/10.1007/s004270050280
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    Expression patterns of threespine stickleback Hox genes and insights into the evolution of the vertebrate body axis (1999)
    Springer
    Development genes and evolution 209 (1999), S. 482-494 
    Details
    ISSN: 1432-041X
    Keywords: Key words Threespine stickleback ; Hox genes ; Hox code ; Body axis ; Tail development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Understanding the patterning mechanisms that operate to promote differentiation of individual segments along the main body axis is an important goal of both developmental and evolutionary biology. In order to gain a better insight into the role of Hox genes in generating diversity of axial plans seen in vertebrates, we have cloned 11 homeobox sequences from an acanthopterygian teleost, the threespine stickleback, and analyzed the expression of 7 of these during embryogenesis. Transcripts are observed in a variety of tissues, including the neural tube, paraxial mesoderm, lateral plate mesoderm, pectoral fins, pronephric ducts, as well as some neural crest-derived structures. Anterior limits of expression in the central nervous system and paraxial mesoderm exhibited both similarities and differences to those of mouse and zebrafish homologs. In both stickleback and zebrafish embryos expression limits within the paraxial mesoderm were detected only within the trunk region in which ribs are attached to all vertebrae. The finding of this pattern in two divergent teleosts as well as in various tetrapod species supports the hypothesis that a Hox precode was present prior to the divergence of ray-finned and lobe-finned fishes and was subsequently used to generate different types of vertebrae in tetrapods. We also describe a dynamic pattern of expression of several stickleback Hox genes associated with the development of the caudal paraxial mesoderm, which suggests uncoupling of the process of segmentation from segmental identity determination. We propose that in fishes the patterning of the tail region is under the control of a separate mechanism from the trunk, which utilizes Hox genes in a different manner.
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    URL: http://dx.doi.org/10.1007/s004270050281
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    Gene expression patterns associated with suppression of odontogenesis in mouse and vole diastema regions (1999)
    Springer
    Development genes and evolution 209 (1999), S. 495-506 
    Details
    ISSN: 1432-041X
    Keywords: Key words Developmental genes ; Mouse ; Microtus rossiaemeridionalis ; Rudimentary ; Tooth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Rodents have a toothless diastema region between the incisor and molar teeth which may contain rudimentary tooth germs. We found in upper diastema region of the mouse (Mus musculus) three small tooth germs which developed into early bud stage before their apoptotic removal, while the sibling vole (Microtus rossiaemeridionalis) had only a single but larger tooth germ in this region, and this developed into late bud stage before regressing apoptotically. To analyze the genetic mechanisms of the developmental arrest of the rudimentary tooth germs we compared the expression patterns of several developmental regulatory genes (Bmp2, Bmp4, Fgf4, Fgf8, Lef1, Msx1, Msx2, p21, Pitx2, Pax9 and Shh) between molars and diastema buds of mice and voles. In diastema tooth buds the expression of all the genes differed from that of molars. The gene expression patterns suggest that the odontogenic program consists of partially independent signaling cascades which define the exact location of the tooth germ, initiate epithelial budding, and transfer the odontogenic potential from the epithelium to the underlying mesenchyma. Although the diastema regions of the two species differed, in both species the earliest difference that we found was weaker expression of mesenchymal Pax9 in the diastema region than in molar and incisor regions at the dental lamina stage. However, based on earlier tissue recombination experiments it is conceivable that the developmental arrest is determined by the early oral epithelium.
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    URL: http://dx.doi.org/10.1007/s004270050282
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