Status of the Endangered Indian Knob Mountainbalm Eriodictyon altissimum (Namaceae) in Central Coastal California

Indian Knob Mountainbalm Eriodictyon altissimum (Namaceae) is a shrub endemic to western San Luis Obispo County in central coastal California, and little has been published regarding it. The species was listed as endangered under the California Endangered Species Act in 1979 and the U.S. Endangered Species Act in 1995. At Federal listing in 1995, Indian Knob mountainbalm was known from six occurrences, two of which were in protected areas, with a total population estimate of 2018, Indian Knob mountainbalm is known from seven occurrences, six of which are in protected areas and one (the largest) mostly in a protected area, with a total population count of 6,489+ individuals in 2016. Two occurrences are likely extirpated. Indian Knob mountainbalm is considered a fire-adapted chaparral plant. Reproduction is reported to be primarily vegetative by underground rhizomes, and it is specialized for substrates with physical disturbances, including: steep rocky slopes, cliff faces, fallen rock debris, sand dunes (shifting sand), roadsides, old graded substrates such as dirt/rock roads, the talus of graded substrates, and trails. We report the species grows up to 5.5 m tall and at 98 to 263 m elevation. In consideration of the life history traits used by Anacker et al. (2013) for rare plants in California, Indian Knob mountainbalm would be considered highly vulnerable to climate change. Using the international standards of IUCN, Indian Knob mountainbalm meets the criteria for classification as critically endangered including the following: geographic range, severely fragmented; extent of occurrence, 34 km2 (km2); area of occupancy, 2 (km2); and quality of habitat, continuing to decline (dense vegetation, lack of recent fire). Coordinated conservation and research are needed to further understand the species, and to restore and maintain the five extant occurrences

Project 8: Precision electron specroscopy to measure the mass of the neutrino

The Project 8 Collaboration is exploring a new technique for the spectroscopy of medium-energy electrons (∼ 1 - 100 keV) with the ultimate goal of measuring the effective mass of the electron antineutrino by the tritium endpoint method. Our method is based on the detection of microwave-frequency cyclotron radiation emitted by magnetically trapped electrons. The immediate goal of Project 8 is to demonstrate the utility of this technique for a tritium endpoint experiment through a high-precision measurement of the conversion electron spectrum of ^(83)mKr . We present concepts for detecting this cyclotron radiation, focusing on a guided wave design currently being implemented in a prototype apparatus at the University of Washington

Single-Electron Detection and Spectroscopy via Relativistic Cyclotron Radiation

It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Although first derived in 1904, cyclotron radiation from a single electron orbiting in a magnetic field has never been observed directly. We demonstrate single-electron detection in a novel radio-frequency spectrometer. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay end point, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments

CRIM1 Complexes with ß-catenin and Cadherins, Stabilizes Cell-Cell Junctions and Is Critical for Neural Morphogenesis

In multicellular organisms, morphogenesis is a highly coordinated process that requires dynamically regulated adhesion between cells. An excellent example of cellular morphogenesis is the formation of the neural tube from the flattened epithelium of the neural plate. Cysteine-rich motor neuron protein 1 (CRIM1) is a single-pass (type 1) transmembrane protein that is expressed in neural structures beginning at the neural plate stage. In the frog Xenopus laevis, loss of function studies using CRIM1 antisense morpholino oligonucleotides resulted in a failure of neural development. The CRIM1 knockdown phenotype was, in some cases, mild and resulted in perturbed neural fold morphogenesis. In severely affected embryos there was a dramatic failure of cell adhesion in the neural plate and complete absence of neural structures subsequently. Investigation of the mechanism of CRIM1 function revealed that it can form complexes with ß-catenin and cadherins, albeit indirectly, via the cytosolic domain. Consistent with this, CRIM1 knockdown resulted in diminished levels of cadherins and ß-catenin in junctional complexes in the neural plate. We conclude that CRIM1 is critical for cell-cell adhesion during neural development because it is required for the function of cadherin-dependent junctions

The Drosophila afadin homologue Canoe regulates linkage of the actin cytoskeleton to adherens junctions during apical constriction

Cadherin-based adherens junctions (AJs) mediate cell adhesion and regulate cell shape change. The nectin–afadin complex also localizes to AJs and links to the cytoskeleton. Mammalian afadin has been suggested to be essential for adhesion and polarity establishment, but its mechanism of action is unclear. In contrast, Drosophila melanogaster’s afadin homologue Canoe (Cno) has suggested roles in signal transduction during morphogenesis. We completely removed Cno from embryos, testing these hypotheses. Surprisingly, Cno is not essential for AJ assembly or for AJ maintenance in many tissues. However, morphogenesis is impaired from the start. Apical constriction of mesodermal cells initiates but is not completed. The actomyosin cytoskeleton disconnects from AJs, uncoupling actomyosin constriction and cell shape change. Cno has multiple direct interactions with AJ proteins, but is not a core part of the cadherin–catenin complex. Instead, Cno localizes to AJs by a Rap1- and actin-dependent mechanism. These data suggest that Cno regulates linkage between AJs and the actin cytoskeleton during morphogenesis

Allosteric effects in cyclophilin mutants may be explained by changes in nano-microsecond time scale motions

The relationship between molecular motion and catalysis in enzymes is debated. Here, simulations of cyclophilin A and three catalytically-impaired mutants reveal a nanosecond-scale interconversion between active and inactive conformations, orders of magnitude faster than previously suggested

Regulation of Classical Cadherin Membrane Expression and F-Actin Assembly by Alpha-Catenins, during Xenopus Embryogenesis

Alpha (α)-E-catenin is a component of the cadherin complex, and has long been thought to provide a link between cell surface cadherins and the actin skeleton. More recently, it has also been implicated in mechano-sensing, and in the control of tissue size. Here we use the early Xenopus embryos to explore functional differences between two α-catenin family members, α-E- and α-N-catenin, and their interactions with the different classical cadherins that appear as tissues of the embryo become segregated from each other. We show that they play both cadherin-specific and context-specific roles in the emerging tissues of the embryo. α-E-catenin interacts with both C- and E-cadherin. It is specifically required for junctional localization of C-cadherin, but not of E-cadherin or N-cadherin at the neurula stage. α-N-cadherin interacts only with, and is specifically required for junctional localization of, N-cadherin. In addition, α -E-catenin is essential for normal tissue size control in the non-neural ectoderm, but not in the neural ectoderm or the blastula. We also show context specificity in cadherin/ α-catenin interactions. E-cadherin requires α-E-catenin for junctional localization in some tissues, but not in others, during early development. These specific functional cadherin/alpha-catenin interactions may explain the basis of cadherin specificity of actin assembly and morphogenetic movements seen previously in the neural and non-neural ectoderm