Search

Axons undergo Wallerian degeneration (WD) distal to a point of injury. In the lesioned PNS, WD may be followed by successful axonal regeneration and functional recovery. However, in the lesioned mammalian CNS, there is no significant axonal regeneration. Myelin-associated proteins (MAPs) have been shown to play significant roles in preventing axonal regeneration in the CNS. Since relatively little is known about such events in human CNS pathologies, we performed an immunohistochemical investigation on the temporal changes of four MAPs during WD in post-mortem spinal cords of 22 patients who died 2 days to 30 years after either cerebral infarction or traumatic spinal cord injury. In contrast to experimental studies in rats, the loss of myelin sheaths is greatly delayed in humans and continues slowly over a number of years. However, in agreement with animal data, a sequential loss of myelin proteins was found which was dependent on their location within the myelin sheath. Myelin proteins situated on the peri-axonal membrane were the first to be lost, the time course correlating with the loss of axonal markers. Proteins located within compact myelin or on the outer myelin membrane were still detectable 3 years after injury in degenerating fibre tracts, long after the disappearance of the corresponding axons. The persistence of axon growth-inhibitory proteins such as NOGO-A in degenerating nerve fibre tracts may contribute to the maintenance of an environment that is hostile to axon regeneration, long after the initial injury. The present data highlight the importance of correlating the well documented, lesion-induced changes that take place in controlled laboratory investigations with those that take place in the clinical domain.

Axons undergo Wallerian degeneration distal to a point of injury. Experimental investigations have documented many of the cellular and molecular events that underlie this behaviour. Since relatively little is known about such events in human CNS pathologies and current experimental intervention strategies indicate the possibility of significant axon regeneration along the original degenerated fibre tract, we performed an immunohistochemical investigation of the dynamics of Wallerian degeneration in post mortem spinal cords of patients who died 2 days to 30 years after either cerebral infarction or traumatic spinal cord injury. Neurofilament (NF) staining demonstrated a spatio‐temporal pattern of axonal loss within degenerating descending nerve fibre tracts that could be detected close to the lesion as early as 12 days after injury and progressed to an almost complete loss of NF immunoreactivity at survival times of 1 year and longer. Immunohistochemistry for glial fibrillary acidic protein revealed a late astrocytic reaction starting at 4 months after injury in the degenerating tracts, leading to the long‐term deposition of a dense astrocytic scar. These events were accompanied by the gradual reduction of myelin basic protein in affected nerve fibre tracts, leading to almost complete loss by 3 years after injury. Since the extracellular matrix molecule chondroitin sulphate proteoglycan (CSPG) is known to be strongly inhibitory for axonal regeneration and to be a major component of gliotic scar tissues, we investigated the possible deposition of CSPG within the degenerating nerve fibre tracts. Apart from a local up‐regulation close to the lesion site, our results show no enhanced CSPG expression within degenerated tracts at any survival time. This suggests that despite the apparent lack of CSPG in Wallerian degeneration, the slow reduction of CNS myelin and the long‐term deposition of a dense astrocytic scar may present an environment that is non‐supportive for axon regrowth.

Test excavations conducted at Drotsky’s Cave have provided important new information on the paleoenvironment and archaeology of the western Kalahari desert during the late and terminal Pleistocene. An occupation layer dated to the terminal Pleistocene was rich in Late Stone Age artefacts, pieces of ostrich egg shell, the remains of carnivorous bullfrogs, springhare, and other fauna. A detailed sediment study, along with the evidence of Angoni vlei rat, climbing mouse, an aquaticXenopusfrog, and side neck turtle confirms that conditions were for the most part, substantially more moist than at present between approximately 30,000 and 11,000 years ago. Analysis of a diatom assemblage dated to the terminal Pleistocene implies that the currently dry Gcwihaba Valley was most likely flowing for much of the year. Our evidence supports findings made at other localities in the Kalahari documenting the existence of especially moist conditions during the terminal Pleistocene.

Although numerous exceptions are well known, organelle DNA is often exclusively or predominantly maternally inherited. In such cases, maternal inheritance is often documented by the study of progeny derived from crosses between parents with distinguishable organelle genotypes. These studies generally detect a single type of progeny, those containing organelles derived from only one of the parents; no progeny containing organelles derived either from the opposite parent or from both parents are found. However, in most cases the number of progeny examined is quite small. I present a simple binomial model of organelle inheritance to determine the power of such experiments to distinguish between the hypothesis of strict maternal inheritance and a more complex hypothesis involving the presence of both organelle types within a progeny array. Extremely large sample sizes of progeny are required to distinguish these two hypotheses with reasonable confidence when organelle transmission is not strictly maternal. As a result, studies involving simple progeny testing may be misleading. Larger samples, more complex breeding designs, or more sensitive molecular methods are required to document adequately strict maternal inheritance of organelles.

A limited examination of the shape-memory properties of a range of gold-copper-zinc alloys has shown that shape-memory occurs in a fairly wide range of compositions in which there is flexibility to optimise other important properties such as hot workability, mechanical strength and ductility.

Theoretical studies of character displacement lead to the view that evolutionary divergence depends primarily on incomplete utilization of available resources. Those models which incorporate constraints preventing complete utilization of resources, even in the absence of competitors, all predict character displacement. Those models which allow greater flexibility of resource use within a species predict correspondingly less divergence. Indeed, Matessi and Jayakar (1980, 1981) based their conditions for occurrence of character displacement on underutilization of resources. I extend a model used by Slatkin (1980, 1983) and Taper and Case (1985) which allows each species to fully utilize its resources in the absence of competitors. I concentrate on the biologically reasonable case in which the species, though similar, differ in their ecological characteristics. As a result of this greater biological realism, I arrive at a different conclusion regarding the conditions which lead to character displacement. The presence of a variety of biological differences between species—including as a subset those which result from resource underutilization—leads to divergence with respect to a quantitatively inherited character, due to interspecific competitive interactions. The resulting displacement can be large and depends little on the parameters chosen. The only exception, involving a character with very low heritability, occurs when the non‐interactive phenotypic differences are much greater than those associated with studies of character displacement in natural populations. Thus, under conditions comparable to those encountered in the field, involving similar yet not identical species, evolutionary divergence is a consequence of interspecific competition.

In contrast to animal mitochondrial DNA, intraspecific variation in chloroplast DNA is thought to be very rare. This presumption has prevented the application to plant population biology of the diversity of molecular genetic techniques now well established for animal mitochondrial DNA. In Trifolium pratense, however, extensive intrapopulational variation does exist. In two paper I report a characterization of unprecedented restriction fragment profile variation within single populations. Populations typically contain a common genotype and many rare ones; often the rare genotypes differ from population to population. While both nucleon and nucleotide diversity, as well as estimates of Wright's FST, indicate a large within-population component and relatively little diversity among populations, the distribution of plastid genotype frequencies in each population is not homogeneous. Estimates of migration rate based on chloroplast DNA genotypes suggest a moderate number of migrants per generation. The unusually high level of genetic variation in Trifolium chloroplast DNA provides the first opportunity to use the plastid genome of plants to study population differentiation. Furthermore, it suggests that the plastid genome may not be as invariant as previously believed, but may instead exhibit high levels of genetic diversity at the population level.

Dictionar german-roman. Academia Republicii Socialiste Romnia, Institutul de Lingvistica. [Bucuresti] 1966. [II] + CI+1.172 pages in-4°. Relie pleine toile, 80 lei.Claudio Magris, Der habsburgische Mythos in der osterreichischen Literatur, Verlag Otto Muller, Salzburg, 1966, 355 S., oS. 132,-. Vom Verf. autorisierte Ubers, von Madeleine von Pasztory nach dem Original Il mito absburgico nella letteratura austriaca moderna, Einaudi Ed., Torino, 1963.Ludwig Rohner, Der deutsche Essay. Materialien zur Geschichte und Asthetik einer literarischen Gattung. Luchterhand-Verlag, Neuwied, 1966. 927 s., DM 65,—.Emil Staiger, Friedrich Schiller, Atlantis-Verlag, Zurich, 1967, 452 S., sFr./DM 28,-.John MacQueen, Robert Henry son: A Study of the Major Narrative Poems, Clarendon Press, Oxford, 1967. vii +229 pp. 30s.Dualities in Shakespeare. By Marion Bodwell Smith. University of Toronto Press, 1966. vii +252 pp. $ 6.50.Five Restoration Adaptations of Shakespeare, Edited with an Introduction by Christopher Spencer, University of Illinois Press, Urbana, 1965.475 pp. $ 12.50.Susie I. Tucker, Protean Shape, a Study in Eighteenth-CenturyVocabulary and Usage. University of London, Athlone Press, 1967. xiv +322 pp. 55sSailendra Kumar Sen, English Literary Criticism in the Second Half of the Eighteenth Century; A Reconsideration, Calcutta University Press, Calcutta, 1965. xiv +410 pp. Rs. 15/—.Carteret's Voyage Round the World 1766-1769. Edited by Helen Wallis. (Works Issued by the Hakluyt Society, second series, vols. CXXIV and CXXV.) Cambridge University Press, 1965.Robert Scholes and Robert Kellogg, The Nature of Narrative. New York, Oxford University Press, 1966. 326 pp.Melvin Rader, Wordsworth: A Philosophical Approach, Oxford, Clarendon Press: Oxford University Press, 1967. 217 pp. 38 s.The Recognition of Edgar Allan Poe, edited by Eric W. Carlson. The University of Michigan Press; Ann Arbor, Michigan, 1966. 316 pp. $ 7.50.Peter M. Axthelm, The Modern Confessional Novel. Yale University Press, New Haven and London, 1967. xii +189 pp. 43s.Seymour L. Gross and John Edward Hardy, editors, Images of the Negro in American Literature. University of Chicago Press, Patterns of Literary Criticism No. 5; Chicago and London, 1966. 321 pp. $2.95 (21s).Floris and Blauncheflur. A Middle English Romance edited with Introduction, Notes and Glossary. Proefschrift. . . Utrecht. . . door Franciscus Catharina de Vries. Groningen, 1966. xii +181 pages.The Middle English Translation of Guy de Chauliac's Anatomy: with Guy's Essay on the History of Medicine. Edited by Bjorn Wallner (Lunds Universitets Årsskrift. N. F. Avd. 1. Bd. 56. Nr. 5.) Lund, CWK Gleerup, 1964. Pp. xxxvi, 250. Sw. Kr. 50.Hans Aarsleff, The Study of Language in England, 1780-1860. Princeton University Press: Princeton, New Jersey, 1967. Pp. 279. Price §7.50 or 60s.Bertil Hedevind, The Dialect of Dentdale in the West Riding of Yorkshire. (Acta Universitatis Upsaliensis. Studia Anglistica Upsaliensia 5.) Uppsala, 1967. xvii+350 pp. Sw. Kr. 60. Distributors: Almqvist & Wiksell, Stockholm.W. A. Hirtle, The Simple and Progressive Form, an Analytical Approach. Les Presses de l'Universite Laval, Quebec, 1967. x+115 pp. $4.

Matica Goulard, Juan Ramon Jimenez y la critica en Escandinavia, Madrid, “Insula”, 1963. 188 S. (Publicaciones del Instituto Ibero-americano Gotemburgo, Suecia.)Evald Johansson. Die Deutschordenschronik des Nicolaus von Jeroschin. Eine sprachliche Untersuchung mit komparativer Analyse der Wortbildung. Ein Beitrag zur Erforschung der Ordenssprache und ihrer Rolle in der Entwicklung der nhd. Schriftsprache. Inaugural-Dissertation. Lund 1964. 328 S. (Lunder germanistische Forschungen. Hrsg. von T. Ahlden. 36). Kr. 35.00.Charles Barber, Linguistic Change in Present-day English. Edinburgh, Oliver & Boyd, 1964. 154 pp. 25s.Festschrift fur Walter Hubner. Herausgegeben von Dieter Riesner und Helmut Gneuss. Berlin: Erich Schmidt Verlag, 1964. Pp. xii +339. Price DM 35.—.Tauno F. Mustanoja, A Middle English Syntax. Part I: Parts of Speech. (Memoires de la Societe Neophilologique de Helsinki, XXIII.) Helsinki, 1960. Pp. 702. $6.00 net.A Middle English Metrical Paraphrase of the Old Testament, III & IV. Edited by Urban Ohlander. (Gothenburg Studies in English 11 & 16.) Goteborg, 1961 & 1963. 132 & 129 pp. Sw. Kr. 15 & 18.The Scottish National Dictionary. Ed. David D. Murison. Vol. V, Part iv: Ken-Langour (1960). 128 pp. Vol. VI, Part i: Langsome-Lose (1962); Part ii: Losel-Merry-leaf (1963); Part iii: Merse-Naither (1964). 384 pp. Edinburgh: The Scottish National Dictionary Association Limited.David Abercbombie, English Phonetic Texts. London: Faber and Faber Ltd, 1964. 125 pp. Price 25s.J. R. Firth, The Tongues of Men & Speech (Language and Language Learning, 2). London: Oxford University Press, 1964. x+211 pp. 8s 6d.R. W. Zandvoort, English in the Netherlands : A Study in Linguistic Infiltration. (Groningen Studies in English, VIII.) Groningen: J. B. Wolters, 1964. XVI + 88 pp.Emma Vorlat, Progress in English Grammar 1585-1735: A Study of the Development of English Grammar and of the Interdependence among the Early English Grammarians. 933 pp. plus prefatory materials. Mimeographed in four volumes. Luxembourg: Editions Armand Peiffer, Avenue Monterey, 1963. Price 600 BF or $12 or 4 gns.Selected Works of St. Thomas More. Utopia. Edited with Introduction and Notes by Edward Surtz, S.J. New Haven and London, Yale University Press, 1964. xxxiv + 158 pp. Cloth 27/6, paper 12/6.John Hazel Smith, A Humanist's 'Trew Imitation': Thomas Watson's Absalom. A Critical Edition and Translation, University of Illinois Press Urbana, 1964 (Illinois Studies in Language and Literature, vol. 52). 293 p. $ 5.00.Leslie Hotson, Mr. W. H. Rupert Hart-Davis, London, 1964. 325 pp. 35s. net.Adina Forsgren, John Gay, Poet 'of a Lower Order'. Comments on His Rural Poems and Other Early Writings. Natur och Kultur: Stockholm, 1964. 249 pp. Kr. 35:-.Arthur Johnston, Enchanted Ground: The Study of Mediaeval Romance in the Eighteenth Century. The Athlone Press of the University of London, 1964. ix + 249 pp. 45 s.Strangers and Pilgrims. By Georg Roppen and Richard Sommer. Norwegian Studies in English, No. 11. Norwegian Universities Press, 1964. 388 pp. N.Kr. 45.00.Helmut Bonheim, Joyce's Benefictions. Perspectives in Criticism, 16. University of California Press. Berkeley and Los Angeles 1964. 144 pp. $4-50.

Illegal logging is a worldwide problem that degrades ecosystems, and even low-risk markets like the United States report ~1000 significant hardwood timber theft cases per year. Due to its high value, bigleaf maple (Acer macrophyllumPursh) is a common target of timber theft in western North America. Using samples from Washington, USA, a single nucleotide polymorphism [SNP] assay was recently developed to facilitate timber poaching investigations in this species based on the single base extension Agena MassARRAY® genotyping system and 133 loci. Our study expands earlier evaluations to include the full 2,000km latitudinal range of bigleaf maple, using 1,142 samples collected from California, USA to British Columbia, CAN. Populations in this study are equivalent to level 3 ecoregions, with sample sizes ranging from 28 (California Coast) to 191 (Washington Coast). Wood-derived DNA concentrations between 0.24 – 6ng/μl yielded SNP call rates > 92%, and DNA concentrations within this range did not influence genotyping call rates. DNA from different tissues showed a weak but significant difference in call rate, with DNA from wood showing a slightly higher call rate than leaves (99.4% vs 97.9%, respectively). Analysis of 108 sample replicates showed that missing genotypes occurred at 0.165% of all loci, and that allelic drop-outs and drop-ins each occurred at frequencies of 0.022% and 0.032%, respectively. Population-specific genotype profile probabilities for Pacific Northwest ecoregions were lower than 1.9 × 10-33; profile probabilities are higher (less powerful) in Californian trees due to lower variability across these SNP loci. Conversely, the geographic origin of trees from Southern Californian ecoregions could be predicted with lower error (8.5% - 11.7%) than trees from the Pacific Northwest (36% - 80%), based on random forest classification. This study provides a rich database for forensic individualization of bigleaf maple across its complete range in western North America.