Physics in the Galtonian sciences of heredity

Physics matters less than we once thought to the making of Mendel. But it matters more than we tend to recognize to the making of Mendelism. This paper charts the variety of ways in which diverse kinds of physics impinged upon the Galtonian tradition which formed Mendelism's matrix. The work of three Galtonians in particular is considered: Francis Galton himself, W. F. R. Weldon and William Bateson. One aim is to suggest that tracking influence from physics can bring into focus important but now little-remembered flexibilities in the Galtonian tradition. Another is to show by example why generalizations about what happens when 'physics' meets 'biology' require caution. Even for a single research tradition in Britain in the decades around 1900, these categories were large, containing multitudes.     

William Bateson from <Emphasis Type="Italic">Balanoglossus</Emphasis> to <Emphasis Type="Italic">Materials for the Study of Variation</Emphasis>: The Transatlantic Roots of Discontinuity and the (un)naturalness of Selection

William Bateson (1861–1926) has long occupied a controversial role in the history of biology at the turn of the twentieth century. For the most part, Bateson has been situated as the British translator of Mendel or as the outspoken antagonist of W.␣F. R. Weldon and Karl Pearson’s biometrics program. Less has been made of Bateson’s transition from embryologist to advocate for discontinuous variation, and the precise role of British and American influences in that transition, in the years leading up to the publication of his massive Materials for the Study of Variation (1894). In this paper, I first attempt to trace Bateson’s development in his early career before turning to search for the development of the moniker “anti-Darwinist” that has been attached to Bateson in well-known histories of the neo-Darwinian Synthesis.     

Signaling Pathways of the F11 Receptor (F11R; a.k.a. JAM-1, JAM-A) in Human Platelets: F11R Dimerization,Phosphorylation and Complex Formation with the Integrin GPIIIa

The F11 receptor (F11R) (a.k.a. Junctional Adhesion Molecule, JAM) was first identified in human platelets as a 32/35 kDa protein duplex that serves as receptor for a functional monoclonal antibody that activates platelets. We have sequenced and cloned the F11R and determined that it is a member of the immunoglobulin (Ig) superfamily of cell adhesion molecules. The signaling pathways involved in F11R-induced platelet activation were examined in this investigation. The binding of M.Ab.F11 to the platelet F11R resulted in granule secretion and aggregation. These processes were found to be dependent on the crosslinking of F11R with the FcγRII by M.Ab.F11. This crosslinking induced actin filament assembly with the conversion of discoidal platelets to activated shapes, leading to the formation of platelet aggregates. We demonstrate that platelet secretion and aggregation through the F11R involves actin filament assembly that is dependent on phosphoinositide-3 kinase activation, and inhibitable by wortmannin. Furthermore, such activation results in an increase in the level of free intracellular calcium, phosphorylation of the 32 and 35 kDa forms of the F11R, F11R dimerization coincident with a decrease in monomeric F11R, and association of the F11R with the integrin GPIIIa and with CD9. On the other hand, F11R-mediated events resulting from the binding of platelets to an immobilized surface of M.Ab.F11 lead to platelet adhesion and spreading through the development of filopodia and lammelipodia. These adhesive processes are induced directly by interaction of M.Ab.F11 with the platelet F11R and are not dependent on the FcγRII. We also report here that the stimulation of the F11R in the presence of nonaggregating (subthreshold) concentrations of the physiological agonists thrombin and collagen, results in supersensitivity of platelets to natural agonists by a F11R-mediated process independent of the FcγRII. The delineation of the two separate F11R-mediated pathways is anticipated to reveal significant information on the role of this cell adhesion molecule in platelet adhesion, aggregation and secretion, and F11R-dependent potentiation of agonist-induced platelet aggregation. The participation of F11R in the formation and growth of platelet aggregates and plaques in cardiovascular disorders, resulting in enhanced platelet adhesiveness and hyperaggregability, may serve in the generation of novel therapies in the treatment of inflammatory thrombosis, heart attack and stroke, and other cardiovascular disorders.     

Problems of epidemiology and prophylaxis of alveococcosis (multilocular echinococcosis): a general review--with particular reference to the U.S.S.R

Lukashenko N. P., 1971. Problems of epidemiology and prophylaxis of alveococcosis (multilocular echinococcosis): a general review—with particular reference to the U.S.S.R. International Journal for Parasitology, 1: 125–134. Alveococcus multilocularis is an extremely dangerous, often fatal, parasite of man. The main endemic areas are southern G.F.R., Austria, Switzerland, northern U.S.A., Canada and Japan. The circulation of Alveococcus depends on complex biocenotic relationships between certain carnivores and numerous microtine rodents. Their roles vary widely according to terrain, reproduction, season, epizootics, animals of prey and interspecific rivalry. The infection rate of definitive hosts each year depends on the prevailing numbers of intermediate hosts in the corresponding biotope, and vice versa. The significance of the fox, polar fox, dog fox, wolf and spotted cat as definitive hosts is considered. Twenty-nine species of rodents have been recorded as intermediate hosts but the roles of insectivores appear insignificant, while those of birds and wild ungulates have yet to be studied. Domestic ungulates probably do not take part in the life-cycle of A. multilocularis. Domestic cats and dogs may be involved accidentally. The role of synanthropic rodents has not yet been fully elucidated but house mice show a high degree of infectivity. Human infection is influenced by ecological factors, living conditions, occupation and level of hygiene practised: dangerous sources of infection are team dogs, unboiled drinking water from melted ice, the skins of fur animals and possibly insects. Secondary sources are other contaminated waters, dust, wild berries and possibly vegetables. Data on the incidence of alveococcosis according to sex is contradictory; the differences between the infection rates of men and women in different regions almost certainly depend on their several modes of life and occupations. The majority of diseased persons are between 19 and 40 years old; infection probably takes place during childhood and is fatal before old age. Prophylactic measures differ markedly from those for (unilocular) echinococcosis, and must be directed towards eliminating the possibility of infecting definitive hosts and towards increased hygiene education.     

A field portable system for the measurement of gas exchange of leaves under natural and controlled conditions: examples with field-grown Eucalyptus pauciflora Sieb. ex Spreng. ssp. pauciflora, E. behriana F. Muell. and Pinus radiata R. Don.

Abstract A field portable system is described which measures the response of gas exchange of one leaf to changes in environmental parameters under controlled conditions, and which simultaneously measures the gas exchange of another leaf as the climatic parameters vary naturally. The system consists of two independently operating cuvettes. It enables detailed studies of photosynthesis and stomata/transpiration of leaves attached to the plant in their natural position. It provides control of temperature, humidity, CO₂ and oxygen concentration (or, alternatively, of other gases) as well as of light. Infrared gas analyzers for CO₂ and H₂O are used which allow similar time constants for the measurement of the two gases. Examples of a diurnal course of gas exchange of a leaf in its natural exposition and of experiments with steady-state responses of gas exchange are presented. In Eucalyptus pauciflora Sieb. ex Spreng. ssp. pauciflora, a set of response curves of CO, assimilation (A) to CO₂, as measured at various leaf temperatures and light levels, shows carboxylation efficiency to be light saturated at the lower photon irradiances the lower the leaf temperature is. Carboxylation efficiency is maximal at 25°C. At ambient CO, partial pressure stomata open in a way that CO₂ assimilation occurs at a rate found within the curvature region of the CO₂ response function of A. The light-independent CO² compensation point as a function of temperature is presented. Applying a combined heat/low humidity pulse (15 or 60 min) on leaves of Eucalyptus behriana F. Muell. or Pinus radiata R. Don, respectively, leads to a lower level of intercellular carbon dioxide partial pressure (C_i) during the decline in A and leaf conductance to water vapour (g). A lower C_i level is maintained during recovery of A and g, A almost reaching the pre-pulse level but not g. The existence of an after-effect indicates that the response to the combined high temperature/low humidity pulse is a multi-step process.     

A novel lipase/chaperone pair from<Emphasis Type="Italic"> Ralstonia</Emphasis> sp. M1: analysis of the folding interaction and evidence for gene loss in<Emphasis Type="Italic"> R. solanacearum</Emphasis>

A microbial strain (referred to as M1) that produces an extracellular lipase was isolated from a soil sample in Vietnam, and identified as a Ralstonia species by partial sequencing of its 16S rDNA. A genomic library was constructed from Pst I fragments, and a colony showing lipase activity was selected for further analysis. Sequencing of the 4.7-kb insert in this clone (named M1-72) revealed one incomplete and three complete ORFs, predicted to encode a partial hypothetical glutaminyl tRNA synthetase (304 aa), a hypothetical transmembrane protein (500 aa), a lipase (328 aa) and a lipase chaperone (352 aa), respectively. Alignment of the insert sequence with the corresponding region of the genome of R. solanacearum GMI1000 (GenBank Accession No. AL646081) confirmed the presence in the latter of the genes for the hypothetical transmembrane protein and glutaminyl tRNA synthetase, which exhibited 89–91% identity to their counterparts in M1. However, R. solanacearum GMI1000 lacks the complete lipase-encoding gene and the major part of the chaperone-encoding gene, creating a so-called black hole. The deduced amino acid sequences of the products of the lipase gene lipA and chaperone gene lipB from strain M1 shared 49.3–60.3% and 23.9–32.7% identity, respectively, with those of the Burkholderia lipase/chaperone subfamily I.2. lipB is located downstream of lipA, and separated from it by only 9 bp, and each gene has a putative ribosome binding site. The mature lipase LipA, a His-tagged derivative (LipAhis), the tagged full-length chaperone LipBhis and a truncated form (LipBhis) lacking the 56 N-terminal residues were expressed in Escherichia coli BL21. LipA, LipAhis and LipBhis could be expressed at high levels (70, 15 and 12 mg/g wet cells, respectively) and were easily purified. However, LipBhis was expressed at a much lower level which precluded purification. The specific activity of purified LipAhis, expressed on its own, was very low (<52 U/mg). However, after co-incubation with the purified LipBhis in vitro, the specific activity of the enzyme was markedly enhanced, indicating that the chaperone facilitated correct folding of the enzyme. A lipase:chaperone ratio of 1:10 was found to be optimal, yielding an enzyme preparation with a specific activity of 650 U/mg.Communicated by H. Ikeda