Medeiros J.S.,The Holden Arboretum |
Begaye A.,San Juan College |
Hanson D.T.,University of New Mexico |
Logan B.,Bowdoin College |
Pockman W.T.,University of New Mexico
Journal of Arid Environments | Year: 2015
Cold temperatures can cause imbalances between light absorption and photosynthetic light utilization, with potential negative consequences for leaf function. Consequently, in response to chilling evergreens typically exhibit increased total pools of photoprotective xanthophyll cycle pigments and greater nocturnal retention of energy dissipating forms. This may preclude opportunistic responses to transient warmer temperatures, however, and become less beneficial as cold spells become rare and/or short-lived, for example, at the low latitude edges of warm deserts. Thus, we hypothesized intrinsic differences in the photoprotective response to chilling between low and high latitude populations of the widespread warm desert evergreen shrub Larrea divaricata. We determined leaf pigment compositions for high and low latitude plants grown in a common garden before and after 7 days of chilling (12/1°C day/night). High and low latitude plants differed in pigment composition before chilling, and plants from both populations adjusted pigment compositions in response to chilling. Chilling, however, induced significantly greater nocturnal retention of xanthophyll cycle pigments as zeaxanthin and antheraxanthin in high latitude plants compared to those from low latitude. These data provide strong evidence for intrinsic differences between high and low latitude populations in their photoprotective responses to both the greenhouse growth environment and to chilling. © 2015 Elsevier Ltd. Source
Fountain D.I.,Fort Lewis College |
Knapp L.,Ashland University |
Baugh K.,San Juan College |
Posner M.,Ashland University |
Fenster S.D.,Fort Lewis College
Genes and Genomics | Year: 2015
Piccolo is an organizational component of the presynaptic active zone, a specialized region of nerve terminals where synaptic vesicles fuse and release their neurotransmitter contents. Alternative splicing (AS) of the mouse Piccolo gene (PCLO) produces two primary splice isoforms: isoform-1 that includes two C2 domains (C2A and C2B) and isoform-2 with only C2A. Genome-wide association studies have identified variations located in or near the C2A domain of human Piccolo that predispose individuals to affective disorders and in rare cases leads to altered brain development. In zebrafish a genome duplication event led to the generation of PCLO-a and PCLO-b: gene paralogs that display strikingly similar genomic organization with other PCLO orthologs. Given this conservation in genomic structure, it is likely that AS patterns of zebrafish PCLO paralogs are similar to mammalian PCLO. We used a RT-PCR strategy to identify four zebrafish isoforms generated from zebrafish PCLO-a and PCLO-b that are equivalent to mouse Piccolo isoform-1 and isoform-2. Additionally, we identified an exon skipping event that leads to exclusion of a 27 nucleotide exon in both zebrafish Piccolo-a and Piccolo-b. Elimination of this exon in mammalian Piccolo alters the calcium binding property of the C2A domain. We also measured transcriptional levels of mouse and zebrafish Piccolo splice variants and demonstrate that despite similarities in AS, there are quantitative differences in gene expression. Our results indicate that AS of Piccolo is similar across diverse taxa and further support the use of zebrafish to study the role of Piccolo in neurodevelopment and synaptic signaling. © 2015 The Genetics Society of Korea and Springer-Science and Media Source
Goettsch B.,International Union for Conservation of Nature |
Hilton-Taylor C.,International Union for Conservation of Nature |
Cruz-Pinon G.,Autonomous University of Baja California Sur |
Duffy J.P.,University of Exeter |
And 79 more authors.
Nature Plants | Year: 2015
A high proportion of plant species is predicted to be threatened with extinction in the near future. However, the threat status of only a small number has been evaluated compared with key animal groups, rendering the magnitude and nature of the risks plants face unclear. Here we report the results of a global species assessment for the largest plant taxon evaluated to date under the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria, the iconic Cactaceae (cacti). We show that cacti are among the most threatened taxonomic groups assessed to date, with 31% of the 1,478 evaluated species threatened, demonstrating the high anthropogenic pressures on biodiversity in arid lands. The distribution of threatened species and the predominant threatening processes and drivers are different to those described for other taxa. The most significant threat processes comprise land conversion to agriculture and aquaculture, collection as biological resources, and residential and commercial development. The dominant drivers of extinction risk are the unscrupulous collection of live plants and seeds for horticultural trade and private ornamental collections, smallholder livestock ranching and smallholder annual agriculture. Our findings demonstrate that global species assessments are readily achievable for major groups of plants with relatively moderate resources, and highlight different conservation priorities and actions to those derived from species assessments of key animal groups. © 2015, Nature Publishing Group. All rights reserved. Source
Agency: NSF | Branch: Continuing grant | Program: | Phase: | Award Amount: 444.76K | Year: 2011
Four Corners STEM Success (FOCUSS) is a collaborative project between Fort Lewis College (a four-year public liberal arts college in Durango, Colorado) and San Juan College (a two-year community college in Farmington, New Mexico), designed to increase the number of students in the Four Corners area who graduate with STEM degrees. San Juan College and Fort Lewis College are geographically close to one another (51 miles apart) and attract many of their students from the same region (western Colorado, northwestern New Mexico, and adjacent parts of Arizona and Utah). Furthermore, Fort Lewis College, which has a tuition waiver for all Native American students, is an excellent transfer destination for the large number of Native American students at San Juan College.
Intellectual Merit. The project consists of four activities: (1) a joint seminar series that brings career-oriented speakers to both institutions; (2) visits by Fort Lewis College STEM faculty and students to San Juan College, to encourage students at San Juan College to continue their education by transferring to Fort Lewis College; (3) an early undergraduate research program run jointly by both institutions; and (4) a tutor/mentor program for Fort Lewis College sophomores and new transfer students, designed to improve retention between first-year courses and upper-level courses at Fort Lewis College. These activities complement existing programs aimed at retaining first-year students and providing support to Native American and Hispanic students at both institutions, and providing undergraduate research experiences to junior and senior STEM majors at Fort Lewis College.
Broader Impact. The project is increasing the number of STEM students who continue from San Juan College to four-year programs, and is increasing the number of STEM majors who graduate from Fort Lewis College. At the same time, the project is increasing the number of underrepresented minorities who graduate with STEM degrees because both San Juan College and Fort Lewis College are designated Native American-Serving, Non-Tribal Institutions by the Department of Education, and serve student bodies that are 27% and 20% Native American, respectively.
Lin C.-L.,University of Massachusetts Medical School |
Evans V.,University of Massachusetts Medical School |
Evans V.,San Juan College |
Shen S.,University of Iowa |
And 2 more authors.
RNA | Year: 2010
CPEB is a sequence-specific RNA binding protein that promotes polyadenylation-induced translation in early development, during cell cycle progression and cellular senescence, and following neuronal synapse stimulation. It controls polyadenylation and translation through other interacting molecules, most notably the poly(A) polymerase Gld2, the deadenylating enzyme PARN, and the eIF4E-binding protein Maskin. Here, we report that CPEB shuttles between the nucleus and cytoplasm and that its export occurs via the CRM1-dependent pathway. In the nucleus of Xenopus oocytes, CPEB associates with lampbrush chromosomes and several proteins involved in nuclear RNA processing. CPEB also interacts with Maskin in the nucleus as well as with CPE-containing mRNAs. Although the CPE does not regulate mRNA export, it influences the degree to which mRNAs are translationally repressed in the cytoplasm. Moreover, CPEB directly or indirectly mediates the alternative splicing of at least one pre-mRNA in mouse embryo fibroblasts as well as certain mouse tissues. We propose that CPEB, together with Maskin, binds mRNA in the nucleus to ensure tight translational repression upon export to the cytoplasm. In addition, we propose that nuclear CPEB regulates specific pre-mRNA alternative splicing. Published by Cold Spring Harbor Laboratory Press. Copyright © 2010 RNA Society. Source