SIAMESE, a plant-specific cell cycle regulator, controls endoreplication onset in Arabidopsis thaliana

Recessive mutations in the SIAMESE (SIM) gene of Arabidopsis thaliana result in multicellular trichomes harboring individual nuclei with a low ploidy level, a phenotype strikingly different from that of wild-type trichomes, which are single cells with a nuclear DNA content of similar to 16C to 32C. These observations suggested that SIM is required to suppress mitosis as part of the switch to endoreplication in trichomes. Here, we demonstrate that SIM encodes a nuclear-localized 14-kD protein containing a cyclin binding motif and a motif found in ICK/KRP (for Interactors of Cdc2 kinase/Kip-related protein) cell cycle inhibitor proteins. Accordingly, SIM was found to associate with D-type cyclins and CDKA;1. Homologs of SIM were detected in other dicots and in monocots but not in mammals or fungi. SIM proteins are expressed throughout the shoot apical meristem, in leaf primordia, and in the elongation zone of the root and are localized to the nucleus. Plants overexpressing SIM are slow-growing and have narrow leaves and enlarged epidermal cells with an increased DNA content resulting from additional endocycles. We hypothesize that SIM encodes a plant-specific CDK inhibitor with a key function in the mitosis-to-endoreplication transition

Preparing Undergraduate Students for Compliance Work?

Anecdotal stories by professionals working in the heritage management industry, specifically Cultural Resource Management (CRM), describe feeling unprepared for the work upon graduating with an undergraduate anthropology degree. Likewise, recent graduates complain that they are unqualified for posted CRM jobs even though many hope to enter the field upon graduation. This anecdotal information raises questions about whether undergraduate academic training adequately prepares students for compliance archaeology. Although anecdotes suggest the academy could do a better job at preparing undergraduate students for compliance work, few resources exist to evaluate these claims. To further complicate the issue, some academics rightly question whether undergraduate education should focus on training students to enter the industry at the expense of a more holistic education. They also question who should be responsible for training students to enter the industry. This article explores these complicated issues and presents initial results from a recent pilot survey conducted in Colorado that was designed to examine undergraduate student preparation for compliance work. Using these preliminary results, we evaluate perceived gaps in training and offer possibilities for addressing these gaps that range from partnerships between CRM and academia to curriculum reform where appropriate

Deepest serendipitous survey of the intermediate galactic latitude from XMM-Newton

vii, 107 leaves : ill. (some col.) ; 29 cm.Includes abstract and appendices.Includes bibliographical references (leaves 59-64).The XMM-Newton Observatory has conducted many observations of the type I active galactic nucleus 1H0707-495. The 0.7 deg [superscript 2] field of view around the AGN was observed over the course of ∼10 years with a total exposure time of 3.75 Ms, allowing for the deepest ever serendipitous survey of intermediate galactic latitude. Combined data from the European Photon Imaging Camera (EPIC) gives the first X-ray "real-colour" image of this field with a limiting flux of 6.72 × 10[superscript -16] , 2.94 × 10[superscript -15] , and 1.14 × 10[superscript -14] ergs/cm[superscript 2] /sec in the 0.5-2, 2-4.5, and 4.5-12 keV, respectively. A total of 128 sources were detected with a photon count [greater than or equal to] 50 not including one arcmin surrounding 1H0707-495. The log(N)-log(S) relation in two bands show consistent slopes with previous surveys and models. Spectra are created and analyzed for the 30 brightest sources and an additional source of interest. Colour-colour diagrams were made using hardness ratios to examine the nature of sources that were too dim to study spectroscopically

Biochemical evidence for an alternate pathway in N-linked glycoprotein biosynthesis

Asparagine-linked glycosylation is a complex protein modification conserved among all three domains of life. Herein we report the in vitro analysis of N-linked glycosylation from the methanogenic archaeon Methanococcus voltae. Using a suite of synthetic and semisynthetic substrates, we show that AglK initiates N-linked glycosylation in M. voltae through the formation of α-linked dolichyl monophosphate N-acetylglucosamine, which contrasts with the polyprenyl diphosphate intermediates that feature in both eukaryotes and bacteria. Notably, AglK has high sequence homology to dolichyl phosphate β-glucosyltransferases, including Alg5 in eukaryotes, suggesting a common evolutionary origin. The combined action of the first two enzymes, AglK and AglC, afforded an α-linked dolichyl monophosphate glycan that serves as a competent substrate for the archaeal oligosaccharyl transferase AglB. These studies provide what is to our knowledge the first biochemical evidence revealing that, despite the apparent similarity of the overall pathways, there are actually two general strategies to achieve N-linked glycoproteins across the domains of life.National Institutes of Health (U.S.) (Grant GM039334

Unaccompanied young females and social workers: meaning-making in the practice space

This article considers the role and importance of the intersubjective practice space created between social workers and unaccompanied young females (UYFs) – girls and young women under 18 years of age, who arrive in a country not in the care of a parent or guardian, and claim asylum in their own right. The voices of UYFs are under-represented in the literature and there is very little research which considers social work with this marginalised group. Through a study of how UYFs and practitioners in England experienced and constructed each other during their everyday practice encounters, we discuss the potential of the practice space for creating mutual understandings and enabling positive changes. Analysis revealed that their subjective and affective experience of their encounters and of each other, both as individual humans and as representations of particular categories (asylum-seeker/looked-after child and professional helper/agent of the state), influenced how they engaged, communicated, co-constructed understandings of each other, and viewed the process and outcomes of the social work contact. We argue for the importance of practice encounter spaces, their distinctiveness from what is written in policy and law, and their potential as a site for creativity and change

Introducing EDEN ISS - A European project on advancing plant cultivation technologies and operations

Plant cultivation in large-scale closed environments is challenging and several key technologies necessary for space-based plant production are not yet space-qualified or remain in early stages of development. The EDEN ISS project foresees development and demonstration of higher plant cultivation technologies, suitable for future deployment on the International Space Station and from a long-term perspective, within Moon and Mars habitats. The EDEN ISS consortium will design and test essential plant cultivation technologies using an International Standard Payload Rack form factor cultivation system for potential testing on-board the International Space Station. Furthermore, a Future Exploration Greenhouse will be designed with respect to future planetary bio-regenerative life support system deployments. The technologies will be tested in a laboratory environment as well as at the highly-isolated German Antarctic Neumayer Station III. A small and mobile container-sized test facility will be built in order to provide realistic mass flow relationships. In addition to technology development and validation, food safety and plant handling procedures will be developed. This paper describes the goals and objectives of EDEN ISS and the different project phases and milestones. Furthermore, the project consortium will be introduced and the role of each partner within the project is explained

Analysis of resistance gene-mediated defense responses in Arabidopsis thaliana plants carrying a mutation in CPR5

In resistant plants, pathogen attack often leads to rapid activation of defense responses that limit multiplication and spread of the pathogen. To investigate the signaling mechanisms underlying this process, we carried out a screen for mutants in the signaling pathway governing resistance in Arabidopsis thaliana to the bacterial pathogen Pseudomonas syringae. This involved screening for suppressor mutations that restored resistance to a susceptible line carrying a mutation in the RPS2 resistance gene. A mutant that conferred resistance by activating defense responses in the absence of pathogens was isolated. This mutant, which carries a mutation at the CPR5 locus and was thus designated cpr5-2, exhibited resistance to P. syringae, spontaneous development of necrotic lesions, elevated PR gene expression in the absence of pathogens, and abnormal trichomes. Resistance gene-mediated defenses, including the hypersensitive response, restriction of pathogen growth, and induction of defense-related gene expression, were functional in cpr5-2 mutant plants. Additionally, in cpr5-2 plants RPS2-mediated induction of PR-1 expression was enhanced, whereas RPM1-mediated induction of ELI3 was not. These findings suggest that CPR5 encodes a negative regulator of the RPS2 signal transduction pathway

Tracking large carnivore dispersal using isotopic clues in claws: An application to cougars across the Great Plains

1. Cougar (Puma concolor) populations, like other large carnivores, have increased during recent decades and may be recolonizing their former ranges in Midwestern North America. The dispersal routes taken by these animals from established populations are unknown and insight into these movements would facilitate their conservation and management. 2. We inferred the origin and migration route of four dispersing cougars using stable hydrogen (δD) and carbon (δ13C) isotope values along one of their claws. We compared isotopic variations within claws to regional and large-scale isoscapes of δD and δ13C values in prey species. Using a likelihood-based assignment approach, we predicted the most likely dispersal route of each cougar (among several least-cost dispersal paths to potential source populations) in a chronological sequence dating back from its final location. 3. Our model predicted the origin of a radio-collared short-distance disperser and inferences about the most likely dispersal corridors for two long-distance dispersers matched reported information from re-sighting events and genetic investigations. 4. Insights about the most likely migration corridors may help identify critical areas and guide future conservation efforts of cougars and other large carnivores. We encourage managers to extend regional isoscapes based on sedentary prey species as they prove to be valuable tools in isotopic tracking of long-distance migration. 5. Our isotopic approach may be extended to other metabolically inert tissues that grow continuously, to investigate dispersal paths of species of interest, providing that individuals disperse across known isotopically structured landscapes

Conservation of a pH-sensitive structure in the C-terminal region of spider silk extends across the entire silk gene family

Spiders produce multiple silks with different physical properties that allow them to occupy a diverse range of ecological niches, including the underwater environment. Despite this functional diversity, past molecular analyses show a high degree of amino acid sequence similarity between C-terminal regions of silk genes that appear to be independent of the physical properties of the resulting silks; instead, this domain is crucial to the formation of silk fibres. Here we present an analysis of the C-terminal domain of all known types of spider silk and include silk sequences from the spider Argyroneta aquatica, which spins the majority of its silk underwater. Our work indicates that spiders have retained a highly conserved mechanism of silk assembly, despite the extraordinary diversification of species, silk types and applications of silk over 350 million years. Sequence analysis of the silk C-terminal domain across the entire gene family shows the conservation of two uncommon amino acids that are implicated in the formation of a salt bridge, a functional bond essential to protein assembly. This conservation extends to the novel sequences isolated from A. aquatica. This finding is relevant to research regarding the artificial synthesis of spider silk, suggesting that synthesis of all silk types will be possible using a single process

Differential roles of two homologous cyclin-dependent kinase inhibitor genes in regulating cell cycle and innate immunity in arabidopsis\u3csup\u3e1[OPEN]\u3c/sup\u3e

© 2016 American Society of Plant Biologists. All Rights Reserved. Precise cell-cycle control is critical for plant development and responses to pathogen invasion. Two homologous cyclindependent kinase inhibitor genes, SIAMESE (SIM) and SIM-RELATED 1 (SMR1), were recently shown to regulate Arabidopsis (Arabidopsis thaliana) defense based on phenotypes conferred by a sim smr1 double mutant. However, whether these two genes play differential roles in cell-cycle and defense control is unknown. In this report, we show that while acting synergistically to promote endoreplication, SIM and SMR1 play different roles in affecting the ploidy of trichome and leaf cells, respectively. In addition, we found that the smr1-1 mutant, but not sim-1, was more susceptible to a virulent Pseudomonas syringae strain, and this susceptibility could be rescued by activating salicylic acid (SA)-mediated defense. Consistent with these results, smr1-1 partially suppressed the dwarfism, high SA levels, and cell death phenotypes in acd6-1, a mutant used to gauge the change of defense levels. Thus, SMR1 functions partly through SA in defense control. The differential roles of SIM and SMR1 are due to differences in temporal and spatial expression of these two genes in Arabidopsis tissues and in response to P. syringae infection. In addition, flow-cytometry analysis of plants with altered SA signaling revealed that SA is necessary, but not sufficient, to change cell-cycle progression. We further found that a mutant with three CYCD3 genes disrupted also compromised disease resistance to P. syringae. Together, this study reveals differential roles of two homologous cyclin-dependent kinase inhibitors in regulating cell-cycle progression and innate immunity in Arabidopsis and provides insights into the importance of cell-cycle control during host-pathogen interactions