A ‘phase-shift’ fusion system for the regulation of foreign gene expression by lambda represser in Gram-negative bacteria

A ‘phase-shift’ translation fusion vector was constructed in which mutually compatible restriction sites BamHI, BelI and BglII are positioned in such a manner that the cut point is in a different reading frame, immediately following the ATG start codon and ribosome-binding site of the λ cro gene. The λ cro gene is expressed from promoter p_R and controlled by a thermosensitive (cI857) λ repressor. The usefulness of the expression vector was demonstrated using a gal gene lacking the ATG start codon and fusing this to the p_R promoter and ATG start codon of the λ cro gene, resulting in cI857-regulated expression of galactokinase. The vector is of general use for foreign gene expression in Escherichia coli when the target gene has a compatible cohesive end (5′-GATC-3′) at the N terminus (provided, for example, by a BamHI linker). The A λ cI857-p_R-cro-galK cassette was cloned into pJRD215, a wide-host-range plasmid and transferred by conjugation to a variety of Gram-negative bacteria. In all cases, thermosensitive regulation of galactokinase could be demonstrated, though the levels of induction varied considerably. These results show that the powerful λ p_R promoter and the efficient A repressor can be used to regulate expression of foreign genes in Gram-negative organisms other than E. coli.     

The selection of the ‘wild’: A combined molecular approach for the identification of pure indigenous fish from hybridised populations

The identification of pure indigenous fish from hybridised populations represents a key issue in fisheries management and conservation biology. In the present study an approach for selection of purebred marble trout (Salmo trutta marmoratus C.) individuals out of admixed populations was set up and assessed. In a first step, baseline data sets of pure marble trout and pure brown trout specimens based on twelve microsatellite loci were used to simulate five consecutive generations of admixture. The baseline and the resulting simulation data sets were then combined with data of a ‘real’ hybridised marble trout population to perform a single individual assignment test as implemented in STRUCTURE. By this procedure the assignment approach was calibrated and it was possible to compare admixture coefficients obtained for individuals from different populations. The ranking of individual admixture coefficients on a plot and comparison with simulated data revealed that the test population was composed of pure marble trout individuals, first generation hybrids between marble trout and brown trout, and hybrid backcross specimens between both groups. However, by defining a critical q-value of 0.1 and additionally integrating individual sequence data of the mtDNA control region, it was possible to indicate individuals, which could be selected for the establishment of a pure marble trout strain.     

The morphology of the toad urinary bladder: A stereoscopic and transmission electron microscopical study

Summary The appearance of the mucosal cell layer of the isolated urinary bladder of the toadBufo marinus, has been examined using stereoscopic and conventional transmission electron microscopy.Three cell types can be identified in surface view, these are granular cells, mitochondriarich cells and goblet cells. Cell boundaries between granular cells are clearly defined by membranous folds along their margins. Although no changes are seen in the stereoscopic electron micrographs when the granular cells are made permeable to water by vasopressin, the changes observed on transmission electron micrographs include swelling of cell bodies and nuclei, filling of intercellular channels with water, and the appearance beneath the mucosal cell membrane surface of electron dense granules.Differences between the appearance of the bladder mucosal cells by the two methods of electron microscopical examination are due largely to water loss when the tissue is freeze dried prior to stereoscopic examination.Grateful thanks are due to Dr. W. D. E. Thomas and Miss Elizabeth Hull of the Long Ashton Research Station for use of the Stereoscan microscope, and also to Dr. John Clamp and Mr. P. J. Summers for help and advice.In receipt of a personal research grant from the Medical Research Council, London.     

Darwin, Herschel, and the role of analogy in Darwin’s origin

In what follows, I consider the role of analogy in the first edition of Darwin’s Origin. I argue that Darwin follows Herschel’s methodology and hence exploits an analogy between artificial and natural selection that allows him generalize selection as a cause of evolutionary change. This argument strategy is not equivalent to an argument from analogy. Reading Darwin’s argument as conforming to Herschel’s two-step methodology of causal analysis followed by generalization allows us to understand the role and placement of Darwin’s discussion of artificial selection in the Origin, without making the mistake of portraying Darwin’s argument for the existence and character of natural selection as an analogical argument.     

The elevated anthocyanin level in the shaded peel of ‘Anjou’ pear enhances its tolerance to high temperature under high light

Pigments, chlorophyll fluorescence, dark respiration, and the antioxidant system in the shaded peel of green ‘Anjou’ pear (Pyrus communis L.) and its bud mutation, red ‘Anjou’, were compared in response to high peel temperature, high light alone or in combination to determine the protective role of anthocyanins under high temperature with or without light. Under high temperature treatment alone, no difference in the maximum quantum yield of PSII (F_V/F_M) was detected between red ‘Anjou’ and green ‘Anjou’; the superoxide dismutase activity and the glutathione pool were up-regulated in green ‘Anjou’ peel but remained unchanged in red ‘Anjou’ peel. Under high temperature coupled with high light, the F_V/F_M of green ‘Anjou’ peel was decreased to a lower value than that of red ‘Anjou’, and significant interaction was detected between temperature and light for both cultivars. Furthermore, the difference in F_V/F_M between red ‘Anjou’ and green ‘Anjou’ under high temperature coupled with high light was significantly larger than that under high light alone, indicating that this larger difference was caused by the interaction between high temperature and high light as no significant difference was detected in F_V/F_M between the two cultivars under high temperature treatment alone at any sampling point. It is concluded that the elevated anthocyanin level in the shaded peel of red ‘Anjou’ does not alter its thermotolerance in the dark, but makes it more tolerant of high temperature under high light.     

The ‘home advantage’ is necessary for a full winner effect and changes in post-encounter testosterone

Winning aggressive contests can both enhance future winning ability and change post-encounter hormones; however, it remains unclear if the context of a fight also influences such winner effects and hormone changes. We investigated this issue by using California mice (Peromyscus californicus) to test if the effect of residency status is necessary to improve future winning ability and alter post-encounter hormones. Male mice were subjected to an aggressive contest and their blood was collected 45 min after the fight. Upon contest initiation, focal mice had a ‘home advantage’ and three prior winning experiences, only one of these factors, or neither factor. Only individuals with a ‘home advantage’ and prior winning experience showed a full winner effect. Post-encounter changes in testosterone and progesterone resulted from an interaction between residency status and winning experience. These data indicate that in male California mice a ‘home advantage’ is necessary to produce the full winner effect and that residency status helps regulate inter-individual variation in the expression of post-encounter testosterone pulses and progesterone changes. Furthermore, these respective behavioral and physiological phenomena might be modulated in a context-specific manner, in part by the surrounding physical environment.     

The ‘experimental stable’ of the BCG vaccine: safety, efficacy, proof, and standards, 1921–1933

The anti-tuberculosis BCG (Bacille Calmette-Guérin) vaccine was conceived and developed between 1905 and 1921 at Pasteur Institutes in France. Between 1921 and A. Calmette’s death in 1933, the vaccine went through a first period of national and international production and distribution for its use in humans. In France these activities were exclusively carried out by Calmette and his collaborators at the Pasteur Institute in Paris. Initially improvised production in a small room in the cellar gave way in 1931 to the construction of the spacious and magnificent ‘New laboratories for research on tuberculosis and the preparation of the BCG’ within the premises of the Pasteur Institute. Presentation and image-building of the vaccine in France insisted on the fact that the BCG was not a commercial specialty but distributed free of charge. The technical monopoly of its production nevertheless lay with the Paris Pasteur Institute and standardization of scientific proof of safety, efficacy and stability was dominated by that Institute in France. In contrast, the international production and distribution of the vaccine was entrusted and transferred, free of charge, to trustworthy laboratories outside France. Multiplication of producers and users led to an increased need for standardization. For this process the analysis distinguishes between the standardization of scientific proof concerning safety, efficacy and stability of the vaccine and standardization of its medical uses. Whereas standardization was rather successful in the inter-war period in France, the international efforts remained rather unsuccessful. Only after world war II under Scandinavian leadership and in the context of mass vaccination programs supported by the WHO and UNICEF was the international standardization effectively implemented and succeeded at least to some extend.     

Multi-locus phylogeny of the family Acrocephalidae (Aves: Passeriformes) – The traditional taxonomy overthrown

We present the first study of the warbler family Acrocephalidae based on one mitochondrial and three nuclear DNA loci, in total 2900 bp, including most or all of the species in three (Acrocephalus, Hippolais and Chloropeta) of the four genera and one species in the fourth genus (Nesillas) in this family. All three genera were suggested to be non-monophyletic, although the non-monophyly of Acrocephalus is not fully convincingly demonstrated. Six major clades were found, which agreed largely with the results from two earlier mitochondrial studies, and for which the names Hippolais, Iduna, Acrocephalus, Calamocichla, Notiocichla and Calamodus have been used. However, the results also revealed some new constellations, due to better resolution of deeper nodes and the inclusion of more taxa. The taxonomic implications are discussed.     

Rove beetles of the subtribe Scopaeina Mulsant & Rey (Coleoptera: Staphylinidae) in the West Palaearctic: Phylogeny, biogeography and species catalogue

A cladistic analysis of the West Palaearctic Scopaeina Mulsant & Rey, 1878 (Coleoptera, Staphylinidae: Paederinae) is presented along with bionomic and biogeographic information. A total of 76 morphological characters were coded for the 88 currently known West Palaearctic species, except for S. bifossicapitata (Outerelo & Oromi, 1987). Results show that Scopaeina comprises two well-supported monophyletic groups in the West Palaearctic, Micranops Cameron, 1913 and Scopaeus Erichson, 1840, which are considered to represent distinct genera. Phylogenetic relationships to Orus Casey, 1884, distributed in North and South America, are briefly discussed. Whereas Micranops is only represented by M. pilicornis (Baudi, 1869) in the region under study, 87 species of Scopaeus are currently known from the West Palaearctic. Within Scopaeus, the cladistic analysis yielded many well-supported monophyletic species groups, most of which are restricted to the West Palaearctic. However, except for Hyperscopaeus Coiffait, 1984, they are not in agreement with the widely used subgeneric concept sensu Coiffait (1952–1984). The following polyphyletic subgenera are consequently synonymized: Alloscopaeus Coiffait, 1968, Anomoscopaeus Coiffait, 1968, Geoscopaeus Coiffait, 1960, and Hyposcopaeus Coiffait, 1960 synn. n. = Scopaeus Erichson, 1840. Nivorus Herman, 1965, and Microscopaeus Coiffait, 1981 synn. n. = Micranops Cameron, 1913. The monotypical genus Coecoscopaeus Coiffait, 1984, established for C. coecus (Peyerimhoff, 1906), is excluded from Scopaeina. Scopaeus mitratus perroti Ochs, 1953 is raised to species rank, and S. nigellus Wollaston, 1864, formerly a synonym of S. minimus Erichson, 1939, is revalidated. Finally, we present a catalogue of species and synonyms of West Palaearctic Scopaeina along with distributional data and five new synonymies of species group names: S. bordei Peyerimhoff, 1914 syn. n. = S. portai Luze, 1910; S. tassiliensis Jarrige, 1958, S. mauretanicus Coiffait, 1960 synn. n. = S. crassipes Wollaston, 1867; S. saoudiensis Coiffait, 1981 = S. sinaicus Coiffait, 1970; S. mateui Coiffait, 1953 syn. n. = S. didymus Erichson, 1840. A lectotype is designated for S. didymus Erichson, 1840.See also Electronic Supplement (Parts 13) at http://www.senckenberg.de/odes/02-02.htm     

Characterization of biocontrol traits in the entomopathogenic nematode Heterorhabditis georgiana (Kesha strain), and phylogenetic analysis of the nematode’s symbiotic bacteria

Our objective was to estimate the biocontrol potential of the recently discovered entomopathogenic nematode species Heterorhabditis georgiana (Kesha strain). Additionally, we conducted a phylogenetic characterization of the nematode’s symbiotic bacterium. In laboratory experiments, we compared H. georgiana to other entomopathogenic nematodes for virulence, environmental tolerance (to heat, desiccation, and cold), and host seeking ability. Virulence assays targeted Acheta domesticus, Agrotis ipsilon, Diaprepes abbreviatus, Musca domestica, Plodia interpunctella, Solenopsis invicta, and Tenebrio molitor. Each assay included H. georgiana and five or six of the following species: Heterorhabditis floridensis, Heterorhabditis indica, Heterorhabditis mexicana, Steinernema carpocapsae, Steinernema feltiae, Steinernema rarum, and Steinernema riobrave. Environmental tolerance assays included Heterorhabditis bacteriophora, H. georgiana, H. indica, S. carpocapsae, S. feltiae, and S. riobrave (except cold tolerance did not include S. carpocapsae or S. riobrave). Host seeking ability was assessed in H. bacteriophora, H. georgiana, S. carpocapsae, and Steinernema glaseri, all of which showed positive orientation to the host with S. glaseri having greater movement toward the host than S. carpocapsae (and the heterorhabditids being intermediate). Temperature range data (tested at 10, 13, 17, 25, 30 and 35 °C) indicated that H. georgiana can infect Galleria mellonella between 13 and 35 °C (with higher infection at 17–30 °C), and could reproduce between 17 and 30 °C (with higher nematode yields at 25 °C). Compared with other nematode species, H. georgiana expressed low or intermediate capabilities in all virulence and environmental tolerance assays indicating a relatively low biocontrol potential. Some novel observations resulted from comparisons among other species tested. In virulence assays, H. indica caused the highest mortality in P. interpunctella followed by S. riobrave; S. carpocapsae caused the highest mortality in A. domesticus followed by H. indica; and S. riobrave was the most virulent nematode to S. invicta. In cold tolerance, S. feltiae exhibited superior ability to cause mortality in G. mellonella (100%) at 10 °C, yet H. bacteriophora and H. georgiana exhibited the ability to produce attenuated infections at 10 °C, i.e., the infections resumed and produced mortality at 25 °C. In contrast, H. indica did not show an ability to cause attenuated infections. Based on the phylogenetic analysis, the bacterium associated with H. georgiana was identified as Photorhabdus luminescens akhurstii.     

Cynanchum and the Cynanchinae (Apocynaceae – Asclepiadoideae): a molecular, anatomical and latex triterpenoid study

The phylogeny of the genus Cynanchum s. str. is studied using cpDNA spacers and ITS. Morphological, anatomical and latex triterpenoid data are interpreted in light of the molecular results, and discrepancies are discussed. Vegetative characters are better indicators of relationship than floral characters, especially corona characters. The monophyly of all Malagasy species and, nested within the latter, of all stem-succulent taxa is ascertained and the genera Folotsia, Karimbolea, Platykeleba and Sarcostemma are subsumed under Cynanchum. One African species, C. galgalense, is excluded from Cynanchum.     

Effect of colour and shape of ‘target’ hosts on the orientation of emigrating adult apterous Myzus persicae in the laboratory

The orientation response of adult apterous Myzus persicae (Sulz.) to targets approximately 1 m distant in an arena was investigated. The targets were combinations of turnip leaves of different known ages and/or paper leaves of the same shape and size, but of different known reflectances. In white arenas, the apterae consistently approached the target which had the greatest percentage reflectance in the range 520–580 nm over targets of lesser reflectance. There was no evidence of olfaction. Compact shapes were approached more frequently than narrow rectangles of the same surface area. Turnip leaves against a black background were approached less frequently than those against a white background. Small black targets against a white background elicited a response, although most apterae became disorientated before reaching them. With increasing target size, this disorientation occurred at increasing distances. These responses to colour and shape are similar to those described by other authors for flight exhausted alatae.

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Effets de la couleur et de la forme des hôtes cibles sur l'orientation au laboratoire d'adultes aptères Myzus persicae en train d'émigrer

Résumé L'étude a porté sur la ré-orientation de l'adulte aptère Myzus persicae en réaction à des cibles situées approximativement à 1 m de distance dans une arène blanche. Les cibles étaient composées de feuilles de navet de différents âges connus et/ou de feuilles de papier de la même taille et même forme, mais de réflectance différente mais connue. Dans des arènes blanches, les adultes aptères ont atteint d'une façon nette les cibles, qui avaient la plus grande réflectance dans la gamme de 520–580 nm. Il n'y avait pas d'indices d'olfaction. Les formes compactes ont été atteintes plus fréquemment que les rectangles étroits de même superficie. Les feuilles de navet sur fond noir étaient atteintes moins fréquemment que celles qui étaient sur un fond blanc. De petites cibles noires sur fond blanc ont provoqué une certaine réaction, bienque la plupart des adultes aptères semblaient devenir désorientées avant de les atteindre. En augmentant la taille de la cible, cette désorientation est apparue à des distances croissantes. Ces réactions à la couleur et à la forme correspondent à celles décrites par d'autres auteurs chez des adultes ailés épuisés par leur vol.

     

The antennae of neopseustid moths: Morphology and phylogenetic implications, with special reference to the sensilla (Insecta, Lepidoptera, Neopseustidae)

The antennae of Lepidoptera Neopseustidae were examined with the scanning electron microscope. The studied species, Nematocentropus cfr. omeiensis, Neopseustis meyricki, Synempora andesae, Apoplania valdiviana and Apoplania penai possess nine types of antennal flagellum sensilla: multiporous large sensilla basiconica, multiporous thin sensilla basiconica, multiporous small sensilla basiconica, multiporous sensilla trichodea, multiporous sensilla coeloconica; uniporous sensilla chaetica; aporous sensilla chaetica, aporous stylus-shaped sensilla chaetica, aporous sensilla styloconica.The multiporous sensillum type here termed “multiporous large sensillum basiconicum” is unknown from other Lepidoptera and probably constitutes an autapomorphy of the family Neopseustidae. This sensillum type is remarkable by having a single base in female Apoplania and Synempora while in male Apoplania it has a bifid or trifid base, and in male Synempora it is composed of two or three incompletely separated hairs. This may be the first recorded example of a sexually dimorphic lepidopteran sensillum type. The stylus-shaped sensillum chaeticum is a primitive type which occurs only in some lower Lepidoptera.     

Fatty acid profiles of polar and non-polar lipids of Pleurotus ostreatus and P. cornucopiae var. ‘citrino-pileatus’ grown at different temperatures

The application of fatty acid (FA) composition data has now extended to studies of physiology, chemotaxonomy, and intrageneric differentiation, as well as to studies of human nutrition. Environmental factors such as nutritional components, oxygen, and temperature are known to affect lipid content and composition in living organisms, including fungi. In the present study, the polar and non-polar lipid content of Pleurotus ostreatus and P. cornucopiae var. citrino-pileatus fruiting bodies produced at temperatures ranging from 12–27 °C and from 17–27 °C, respectively, were analysed to evaluate the effect of temperature on lipid composition in these mushrooms. Results showed that lowering the growth temperature below 17 °C generally provided an expected increase in FA unsaturation in polar and non-polar lipids of P. ostreatus. Although raising the temperature above 17 °C did not show any clear-cut tendency in FA unsaturation, it did reveal that growth temperature had a differential effect on the FA profiles in fruiting bodies of P. ostreatus and P. cornucopiae. This study suggests that care should be taken when using FA content and unsaturation data for physiological, chemotaxonomic, and intrageneric differentiation studies, and that it may be possible to manipulate lipid unsaturation in Pleurotus spp. through modified growth temperatures.