Root:soil adhesion in the maize rhizosphere: the rheological approach

This study was designed to investigate the strength of attachment of plant seedling roots to the soil in which they were grown. The study also assessed the effects of differing soil textures and differing soil matric potentials upon the strength of the root:soil attachment. A device for growing roots upon a soil surface was designed, and was used to produce roots which were attached to the soil. In order to quantify root:soil adhesion, roots of maize seedlings, grown on the soil surface, were subsequently peeled off using a universal test machine, in conjunction with simultaneous time-lapse video observation. To clarify the partitioning of energy in the root:soil peeling test, separate mechanical tests on roots, and on two adherent remoulded topsoil balls were also carried out. The seedling root was characterised by a low bending stiffness. The energy stored in bending was negligible, compared to the root:soil adhesion energy. The mechanical properties of two adherent remoulded topsoil balls were a decrease of the soil:soil adhesion energy as the soil:soil plastic energy increased. These two parameters were therefore interdependent. Using a video-camera system, it was possible to separate the different processes occurring during the root:soil peeling test, in particular, the seed:soil adhesion and the root:soil soil adhesion. An interpretation of the complex and variable force:displacement curves was thus possible, enabling calculation of the root:soil interfacial rupture energy. At a given suction (10 kPa), the results of the peeling test showed a clear soil texture effect on the value of the root:soil interfacial rupture energy. In contrast, for the same silty topsoil, the effect of the soil water suction on the value of the interfacial rupture energy was very moderate. The root:soil interfacial rupture energy was controlled mainly by a product of microscopic soil specific surface area and the macroscopic contact surface area between the root and the soil. Biological and physical interactions contributing to root:soil adhesion such as root:soil interlocking mechanics were also analysed and discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Evidence against the 1:2:2:1 quartet DMPO spectrum as the radical adduct of the lipid alkoxyl radical.

It was reported that the electron paramagnetic resonance (EPR) spectrum of 5,5-dimethyl-1-pyrroline N-oxide (DMPO)/lipid alkoxyl radical exhibited a quartet with 1:2:2:1 relative intensity that is identical to that of DMPO/hydroxyl radical (K. M. Schaich and D. C. Borg, 1990, Free Radicals Res. Commun. 9, 267-278). We repeated these EPR experiments using HPLC separation of radical adducts and isotope substitution. We found that the HPLC/EPR chromatogram of the radical adduct with a 1:2:2:1 quartet obtained by the reduction of methyl linoleate hydroperoxide (MLOOH) with Fe2+ exhibited identical retention time to that of the DMPO/OH radical adduct obtained from the Fenton reaction in two different solvent systems. Upon performing the same reaction in 17O-enriched water, the 17O-hyperfine coupling constants due to DMPO/17OH were identified. Ultimately, approximately 80-90% of the total DMPO/OH is derived from water by an iron-dependent nucleophilic addition reaction. Initially, a water-independent mechanism also significantly contributes to DMPO/OH formation. Regardless of its mechanism of formation, the 1:2:2:1 quartet radical adduct of DMPO formed during the reduction of MLOOH by Fe2+ is in fact DMPO/OH.     

Essay review: Museums: Revisiting sites in the history of the natural sciences

Mary P. Winsor,Reading the shape of Nature: Comparative zoology at the Agassiz Museum (Chacago: University of Chicago Press, 1991); Ronald Rainger,An Agenda for Antiquty: Henry Fairfield Osborn and Vertedrate Paleontology at the American Meseum of Natural History, 1890–1935 (Tuscaloosa: University of Aladama Press, 1991).     

Systematics and biogeography of the subantarctic Leptusa (Coleoptera: Staphylinidae: Aleocharinae: Homalotini)

Leptusa atriceps and L. antarctica, flightess representatives of the nearly global genus Leptusa in the remote and widely distributed subantarctic islands, are taxonomically revised. Identity and the widely disjunct distribution of L. atriceps on Falkland, South Georgia, Marion, Crozet and Kerguelen Islands are confirmed. Leptusa antarctica is found to be a complex of five species restricted to the subantarctic islands of New Zealand. Two of these species, L. sparsepunctata and L. nesiotes are here reinstated from synonymy and two others, Leptusa insulae sp. nov. and Leptusa steeli sp. nov., are described as new to science. The monophyly of subantarctic Leptusa species united in the subgenus Halmaeusa was determined by a phylogenetic study of five exemplar homalotine genera and 17 representatives of Leptusa from South America and the Holarctic based on 76 adult morphological characters. Phylogenetic placement of Halmaeusa was not firmly established. Nanoglossa, a temperate South American subgenus of Leptusa was found as a possible sister group to Halmaeusa. The distribution of Halmaeusa species with two to four species that occur sympatrically on Campbell and Auckland Islands, and other species distributed across several remote islands, provides a framework for future biogeographic study of the subantarctic Leptusa.

http://www.zoobank.org/urn:lsid:zoobank.org:act:82509B9D-4BF6-47E1-B6F7-396ED193A0FA; http://www.zoobank.org/urn:lsid:zoobank.org:act:40A3D6FC-27FF-4070-88CA-1B519ABE760A     

Valproic acid phase shifts the rhythmic expression of Period2::Luciferase

Valproic acid (VPA) is an anticonvulsant used to treat bipolar disorder, a psychiatric disease associated with disturbances in circadian rhythmicity. Little is known about how VPA affects circadian rhythms. The authors cultured tissues containing the master brain pacemaker for circadian rhythmicity, the suprachiasmatic nuclei (SCN), and skin fibroblasts from transgenic PERIOD2::LUCIFERASE (PER2::LUC) mice and studied the effect of VPA on the circadian PER2::LUC rhythm by measuring bioluminescence. VPA (1 mM) significantly phase advanced the PER2::LUC rhythm when applied at a time point corresponding to the lowest (trough, ~ZT 0) PER2::LUC expression but phase delayed the PER2::LUC rhythm when the drug was administered at the time of highest (peak, ~ZT 12) protein expression. In addition, it significantly increased the overall amplitude of PER2::LUC oscillations at time points at or close to ZT 12 but had no effect on period. Real-time PCR analyses on mouse and human fibroblasts revealed that expressions of other clock genes were increased after 2 h treatment with VPA. Because VPA is known to inhibit histone deacetylation, the authors treated cultures with an established histone deacetylation inhibitor, trichostatin A (TSA; 20 ng/mL), to compare the effect of VPA and TSA on molecular rhythmicity. They found that TSA had similar effects on the PER2::LUC rhythm as VPA. Furthermore, VPA and TSA significantly increased acetylation on histone H3 but in comparison little on histone H4. Lithium is another commonly used treatment for bipolar disorder. Therefore, the authors also studied the impact of lithium chloride (LiCl; 10 mM) on the PER2::LUC rhythm. LiCl delayed the phase, but in contrast to VPA and TSA, LiCl lengthened the PER2::LUC period and had no effect on histone acetylation. These results demonstrate that VPA can delay or advance the phase, as well as increase the amplitude, of the PERIOD2::LUCIFERASE rhythm depending on the circadian time of application. Furthermore, the authors show that LiCl delays the phase and lengthens the period of the PER2::LUC rhythm, confirming previous reports on circadian lithium effects. These different molecular effects may underlie differential chronotherapeutic effects of VPA and lithium.     

The Machete and the Cross: Campesino Rebellion in Yucatan: The Conquest of the Last Maya Kingdom: Río Azul: An Ancient Maya City

The Machete and the Cross: Campesino Rebellion in Yucatan. Don E. Dumond. Lincoln: University of Nebraska Press, 1997.571pp.
The Conquest of the Last Maya Kingdom. Grant D. Jones. Stanford, CA: Stanford University Press, 1998.568 pp.
Río Azul: An Ancient Maya City. Richard E. W. Adams. Norman: University of Oklahoma Press, 1999. 238 pp.     

The Cambridge History of the Native Peoples of the Americas: Vol. 2: Mesoamerica, Part 1.; The Cambridge History of the Native Peoples of the Americas: Vol. 2: Mesoamerica, Part 2.

The Cambridge History of the Native Peoples of the Americas: Vol. 2: Mesoamerica, Part 1. Richard E. W. Adams and Murdo J. MacLeod. eds. Cambridge: Cambridge University Press, 2000. 571 pp.
The Cambridge History of the Native Peoples of the Americas: Vol. 2: Mesoamerica, Part 2. Richard E. W. Adams and Murdo J. MacLeod. eds. Cambridge: Cambridge University Press, 2000. 455 pp.     

Marine nitrogen: Phosphorus stoichiometry and the global N:P cycle

Nitrogen supply is often assumed to limitmarine primary production. A global analysis of totalnitrogen (N) to phosphorus (P) molar ratios shows thattotal N:P is low (<16:1) in some estuarine andcoastal ecosystems, but up to 100:1 in open oceans.This implies that elements other than N may limitmarine production, except in human impacted, estuarineor coastal ecosystems. This pattern may reconcileconflicting enrichment studies, because N additionfrequently increases phytoplankton growth where totalN:P is expected to be low, but P, Fe, or Si augmentphytoplankton growth in waters where total N:P ishigh. Comparison of total N:P stoichiometry betweenmarine and freshwaters yields a model of the form ofthe aquatic N:P cycle.     

Characterisation of the Salmonella O:8 antigen in the O-chain of the lipopolysaccharide produced by Salmonella virginia O:8.

The antigenic O-polysaccharide of the lipopolysaccharide produced by Salmonella virginia (O:8), analyzed by methylation, partial acid hydrolysis, and one- and two-dimensional nuclear magnetic resonance methods, was found to be a polymer of a repeating pentasaccharide unit composed of D-mannose, D-galactose, L-rhamnose, D-abequose, and O-acetyl (2:1:1:1:1.3) and having the following structure: [formula; see text] The disaccharide structure alpha-D-Abep-(1----3)-L-Rhap was identified as the Salmonella O:8 antigenic factor epitope, since the removal of alpha-D-Abep residues from the O-polysaccharide left a residual tetrasaccharide repeating unit backbone that did not show reaction with Salmonella type O:8 factor antiserum.     

Oka: Behind the Barricades: Kanehsatake: 270 Years of Resistance: Spudwrench: Kahnawake Man: My Name is Kahentiiosta: Acts of Defiance

Oka: Behind the Barricades. 1998. 312 minutes. For more information contact the National Film Board of Canada, 3155 Côte de Lisse Rd., St. Laurent, Quebec H4N 2N4. Series of four videos:
Kanehsatake: 270 Years of Resistance. 1993. 120 minutes. Directed by Alanis Obomsawin .
Spudwrench: Kahnawake Man. 1997. 58 minutes. Directed by Alanis Obomsawin .
My Name is Kahentiiosta. 1995. 30 minutes. Directed by Alanis Obomsawin .
Acts of Defiance. 1992. 104 minutes. Directed by Alec MacLeod .     

Focus: Vaccines: Trends in the Cost and Utilization of Omalizumab in the Medicare Population: 2013-2017

Background: Omalizumab has been demonstrated to be effective in treating chronic spontaneous urticaria (CSU) and was FDA approved for this indication in 2014. Previous work has shown that access to injectable biologics varies across US counties. In the present study we evaluate geographic and temporal trends in the utilization of omalizumab in the Medicare population by dermatologists, with its use by allergists and pulmonologists as comparators. Methods: We analyzed year-over-year trends in omalizumab utilization across geographic regions using the Medicare Provider Utilization and Payment Data: Part D files. Results: Utilization of omalizumab by dermatologists increased rapidly after its FDA approval, from 0.08 claims/100,000 enrollees totaling $209/100,000 enrollees in 2014 to 1.45 claims/100,000 enrollees totaling $3115/100,000 enrollees in 2017. Nonetheless, prescribing dermatologists were present in only 2.8% (95% Confidence Interval (CI): 2.0%-3.9%) and 0.2% (95% CI: 0.0%-0.5%) of metropolitan and non-metropolitan counties, respectively, in 2017, demonstrating limited availability, especially in non-metropolitan counties. Similarly, prescribers of any specialty were available in 32.9% (95% CI: 30.2%-35.6%) and 3.8% (95% CI: 3.1%-4.8%) of metropolitan and non-metropolitan counties, respectively, in 2017. Conclusions: Our data suggest that despite increasing omalizumab utilization, there remains a lack of access across many counties, particularly in non-metropolitan regions. Efforts to expand omalizumab prescriber accessibility in these counties may improve outcomes for patients with CSU.     

Revision of the genus Chalcasthenes Arrow (Coleoptera: Scarabaeidae: Dynastinae: Oryctoderini) from the Solomon Islands

The genus Chalcasthenes Arrow (Dynastinae: Oryctoderini), a scarab beetle genus endemic to the Solomon Islands, is reviewed. Based on examination of type specimens, the genus Strehlia Frey (Rutelinae: Rutelini: Parastasiina) is a new junior synonym of Chalcasthenes . The historical classification of these genera (either in the subfamily Dynastinae or Rutelinae) and character-based criteria for assigning the taxa to the Dynastinae are provided. We discuss character states that support the monophyly of members of the genus Chalcasthenes, comment on the distribution and biogeography of species in the genus and provide a key to species. The genus includes four species: Chalcasthenes divinus Endrödi, Chalcasthenes pulcher Arrow, Chalcasthenes squamigerus Frey new combination and Chalcasthenes styracoceros Jameson and Ratcliffe n. sp. Species hypotheses are corroborated based on evidence from Pleistocene geological reconstructions of the Solomon Islands, geographic variation of bird species in the region and development in scarab beetles.     

Science Studies: Beyond the War Zone

Ecologies of Knowledge: Work and Politics in Science and Technology. Susan Leigh Star. ed. Albany: State University of New York Press, 1995. 421 pp.
Beyond the Natural Body: An Archeology of Sex Hormones. Nelly Oudshoorn. London: Routledge, 1994. 195 pp.
Science and Technology in. Multicultural World: The Cultural Politics of Facts and Artifacts. David J. Hess. New York: Columbia University Press, 1995. 306 pp.     

Decoding the Discourses: Feminism and Science

Revisioning Women, Health and Healing: Feminist, Cultural and Technoscience Perspectives. Adele E. Clarke and Virginia L. Olesen. eds, New York: Routledge, 1999. 374 pp.
Technologies of Procreation: Kinship in the Age of Assisted Conception. Jeanette Edwards. Sarah Franklin. Eric Hirsch, Frances Price, and Marilyn Strathern. New York: Routledge, 1999. 236 pp.
Testing the Women, Testing the Fetus: The Social Impact of Amniocentesis in America. Rayna Rapp. New York: Routledge, 1999. 361 pp.     

Platelet adhesiveness and aggregation: the collagen:glycosyl, polypeptide:N-acetylgalactosaminyl and glycoprotein:galactosyl transferases of human platelets

Four glycoprotein:glycosyl transferases were identified, purified, and characterized from human platelets. The enzymes present were collagen:glc, collagen:gal, polypeptide:galNAc, and glycoprotein:gal; the fetuin:glcNAc transferase was absent. Each of the 4 transferases was found to be almost exclusively bound to the platelet plasma membrane. Incubation of platelet homogenates without exogenous acceptors yielded no transfer of monosaccharide, indicating the complete lack of endogenous acceptors. These results lead to the interesting speculation that the transferases may not be responsible in the mature platelet for glycoprotein synthesis at all, but rather that they may function for intercellular adhesion and the primary step in hemostasis, the adhesion of collagen to platelets.     

Senescence: the good the bad and the dysfunctional

Nearly 50 years have elapsed since Hayflick challenged the dogma that individual human cells were immortal by demonstrating that after a predictable number of cellular divisions, normal human fibroblasts eventually entered a state of permanent growth arrest [Hayflick L: The limited in vitro lifetime of human diploid cell strains. Exp Cell Res 1965, 37:614-636.; Hayflick L, Moorhead PS: The serial cultivation of human diploid cell strains. Exp Cell Res 1961, 25:585-621]. This growth arrest, referred to as senescence, was hypothesized to function as a tumor suppressive mechanism, capable of limiting the replicative capacity of an incipient tumor cell. While originally met with skepticism, the existence of senescence and its importance as a tumor suppressive mechanism is now accepted. Here, we highlight this work and introduce studies that indicate that while senescent cells themselves cannot produce a neoplasia, they possess the ability to promote the growth of nearby preneoplastic cells and in this way may contribute to age-related increases in tumor incidences. This added level of complexity suggests that senescence functions as a biological 'double edged sword.'     

Spectrin Domain of Eukaryotic Initiation Factor 3a Is the Docking Site for Formation of the a:b:i:g Subcomplex

eIF3a (eukaryotic translation initiation factor 3a), one of the core subunits of the eIF3 complex, has been implicated in regulating translation of different mRNAs and in tumorigenesis. A subcomplex consisting of eIF3a, eIF3b, eIF3g, and eIF3i (eIF3(a:b:i:g)) has also been identified. However, how eIF3a participates in translational regulation and in formation of the eIF3(a:b:i:g) subcomplex remain to be solved. In this study, we used the tandem affinity purification approach in combination with tandem MS/MS and identified the spectrin domain of eIF3a as the docking site for the formation of eIF3(a:b:i:g) subcomplex. Although eIF3b and eIF3i bind concurrently to the spectrin domain of eIF3a within ∼10–15 amino acids apart, eIF3g binds to eIF3a indirectly via binding to the carboxyl-terminal domain of eIF3b. The binding of eIF3b to the spectrin domain of eIF3a occurs in its RNA recognition motif domain where eIF3j also binds in a mutually exclusive manner. Together, we conclude that the spectrin domain of eIF3a is responsible for the formation of eIF3(a:b:i:g) subcomplex and, because of mutually exclusive nature of bindings of eIF3a and eIF3j to eIF3b, different subcomplexes of eIF3 likely exist and may perform noncanonical functions in translational regulation.     

CRONOS: the cross-reference navigation server

Summary: Cross-mapping of gene and protein identifiers betweendifferent databases is a tedious and time-consuming task. Toovercome this, we developed CRONOS, a cross-reference serverthat contains entries from five mammalian organisms presentedby major gene and protein information resources. Sequence similarityanalysis of the mapped entries shows that the cross-referencesare highly accurate. In total, up to 18 different identifiertypes can be used for identification of cross-references. Thequality of the mapping could be improved substantially by exclusionof ambiguous gene and protein names which were manually validated.Organism-specific lists of ambiguous terms, which are valuablefor a variety of bioinformatics applications like text miningare available for download. Availability: CRONOS is freely available to non-commercial usersat http://mips.gsf.de/genre/proj/cronos/index.html, web servicesare available at http://mips.gsf.de/CronosWSService/CronosWS?wsdl. Contact: brigitte.waegele{at}helmholtz-muenchen.de Supplementary information: Supplementary data are availableat Bioinformatics online. The online Supplementary Materialcontains all figures and tables referenced by this article. Associate Editor: Martin Bishop     

Transposon mutagenesis of the anaerobic commensal, Bacteroides fragilis, using the EZ::TN5 transposome

Genetic analysis of Bacteroides fragilis (BF) is hindered because of the lack of efficient transposon mutagenesis methods. Here, we describe a simple method for transposon mutagenesis using EZ::TN5, a commercially available system that we optimized for use in BF638R. The modified EZ::TN5 transposon contains an Escherichia coli conditional origin of replication, a kanamycin resistance gene for E. coli, an erythromycin resistance gene for BF , and 19 basepair transposase recognition sequences on either ends. Electroporation of the transposome (transposon-transposase complex) into BF638R yielded 3.2 ± 0.35 × 10(3) CFU μg(-1) of transposon DNA. Modification of the transposon by the BF638R restriction/modification system increased transposition efficiency sixfold. Electroporation of the EZ::TN5 transposome results in a single-copy insertion of the transposon evenly distributed across the genome of BF638R and can be used to construct a BF638R transposon library. The transposon was also effective in mutating a BF clinical isolate and a strain of the related species, Bacteroides thetaiotaomicron. The EZ::TN5-based mutagenesis described here is more efficient than other transposon mutagenesis approaches previously reported for BF.