Mojave Applied Ecology Notes Summer 2009

BLM and wildfire protection in the Mojave, studies of the sticky ringstem flowering phenology in Lake Mead NRA, restoration work within gypsum soils, post-fire response synthesis for Mojave and Sonoran desert

Structural Features of Thyroglobulin Linked to Protein Trafficking

Thyroglobulin must pass endoplasmic reticulum (ER) quality control to become secreted for thyroid hormone synthesis. Defective thyroglobulin, blocked in trafficking, can cause hypothyroidism. Thyroglobulin is a large protein (~2750 residues) spanning regions I–II–III plus a C-terminal cholinesterase-like domain. The cholinesterase-like domain functions as an intramolecular chaperone for regions I–II–III, but the folding pathway leading to successful thyroglobulin trafficking remains largely unknown. Here, informed by the recent three-dimensional structure of thyroglobulin as determined by cryo-electron microscopy, we have bioengineered three novel classes of mutants yielding three entirely distinct quality control phenotypes. Specifically, upon expressing recombinant thyroglobulin, we find that first, mutations eliminating a disulfide bond enclosing a 200-amino acid loop in region I have surprisingly little impact on the ability of thyroglobulin to fold to a secretion-competent state. Next, we have identified a mutation on the surface of the cholinesterase-like domain that has no discernible effect on regional folding yet affects contact between distinct regions and thereby triggers impairment in the trafficking of full-length thyroglobulin. Finally, we have probed a conserved disulfide in the cholinesterase-like domain that interferes dramatically with local folding, and this defect then impacts on global folding, blocking the entire thyroglobulin in the ER. These data highlight variants with distinct effects on ER quality control, inhibiting domain-specific folding; folding via regional contact; neither; or both

Intraoperative electrocochleographic characteristics of auditory neuropathy spectrum disorder in cochlear implant subjects

Auditory neuropathy spectrum disorder (ANSD) is characterized by an apparent discrepancy between measures of cochlear and neural function based on auditory brainstem response (ABR) testing. Clinical indicators of ANSD are a present cochlear microphonic (CM) with small or absent wave V. Many identified ANSD patients have speech impairment severe enough that cochlear implantation (CI) is indicated. To better understand the cochleae identified with ANSD that lead to a CI, we performed intraoperative round window electrocochleography (ECochG) to tone bursts in children (n = 167) and adults (n = 163). Magnitudes of the responses to tones of different frequencies were summed to measure the “total response” (ECochG-TR), a metric often dominated by hair cell activity, and auditory nerve activity was estimated visually from the compound action potential (CAP) and auditory nerve neurophonic (ANN) as a ranked “Nerve Score”. Subjects identified as ANSD (45 ears in children, 3 in adults) had higher values of ECochG-TR than adult and pediatric subjects also receiving CIs not identified as ANSD. However, nerve scores of the ANSD group were similar to the other cohorts, although dominated by the ANN to low frequencies more than in the non-ANSD groups. To high frequencies, the common morphology of ANSD cases was a large CM and summating potential, and small or absent CAP. Common morphologies in other groups were either only a CM, or a combination of CM and CAP. These results indicate that responses to high frequencies, derived primarily from hair cells, are the main source of the CM used to evaluate ANSD in the clinical setting. However, the clinical tests do not capture the wide range of neural activity seen to low frequency sounds

Aerodynamic Characteristics of Two Rotary Wing UAV Designs

This paper presents the results of an experimental investigation of two rotary-wing UAV designs. The primary goal of the investigation was to provide a set of interactional aerodynamic data for an emerging class of rotorcraft. The present paper provides an overview of the test and an introduction to the test articles, and instrumentation. Sample data in the form of a parametric study of fixed system lift and drag coefficient response to changes in configuration and flight condition for both rotor off and on conditions are presented. The presence of the rotor is seen to greatly affect both the character and magnitude of the response. The affect of scaled stores on body drag is observed to be dependent on body shape

A hypoenergetic diet with decreased protein intake does not reduce lean body mass in trained females

Purpose Increasing protein intake during energy restriction (ER) attenuates lean body mass (LBM) loss in trained males. However, whether this relationship exists in trained females is unknown. This study examined the impact of higher compared to lower protein intakes (35% versus 15% of energy intake) on body composition in trained females during 2 weeks of severe ER. Methods Eighteen well-trained females completed a 1-week energy balanced diet (HD100), followed by a 2-week hypoenergetic (40% ER) diet (HD60). During HD60, participants consumed either a high protein (HP; 35% protein, 15% fat) or lower protein (CON; 15% protein, 35% fat) diet. Body composition, peak power, leg strength, sprint time, and anaerobic endurance were assessed at baseline, pre-HD60, and post-HD60. Results Absolute protein intake was reduced during HD60 in the CON group (from 1.6 to 0.9 g·d·kgBM−1) and maintained in the HP group (~ 1.7 g·d·kgBM−1). CON and HP groups decreased body mass equally during HD60 (− 1.0 ± 1.1 kg; p = 0.026 and − 1.1 ± 0.7 kg; p = 0.002, respectively) and maintained LBM. There were no interactions between time point and dietary condition on exercise performance. Conclusion The preservation of LBM during HD60, irrespective of whether absolute protein intake is maintained or reduced, contrasts with findings in trained males. In trained females, the relationship between absolute protein intake and LBM change during ER warrants further investigation. Future recommendations for protein intake during ER should be expressed relative to body mass, not total energy intake, in trained females

Angular clustering of galaxies at 3.6 microns from the Spitzer Wide-area Infrared Extragalactic (SWIRE) Survey

We present the first analysis of large-scale clustering from the Spitzer Wide-area Infrared Extragalactic legacy survey (SWIRE). We compute the angular correlation function of galaxies selected to have 3.6 m fluxes brighter than 32 Jy in three fields totaling 2 deg2 in area. In each field we detect clustering with a high level of significance. The amplitude and slope of the correlation function is consistent between the three fields and is modeled as w() ¼ A1 with A ¼ (0:6 0:3) ; 10 3; ¼ 2:03 0:10. With a fixed slope of ¼ 1:8, we obtain an amplitude of A ¼ (1:7 0:1) ; 10 3. Assuming an equivalent depth of K 18:7 mag we find that our errors are smaller but our results are consistent with existing clustering measurements in K-band surveys and with stable clustering models. We estimate our median redshift z ’ 0:75, and this allows us to obtain an estimate of the three-dimensional correlation function (r), for which we find r0 ¼ 4:4 0:1 h 1 Mpc

Effect of Intensive Training on Mood With No Effect on Brain-Derived Neurotrophic Factor

Purpose Monitoring mood state is a useful tool for avoiding non-functional overreaching (NFOR). Brain derived neurotrophic factor (BDNF) is implicated in stress-related mood disorders. The purpose of the present study was to investigate the impact of intensified training-induced mood disturbance on plasma BDNF concentrations at rest and in response to exercise.  Methods Eight cyclists performed 1 week of normal (NT), 1 week of intensified (INT) and 1 week of recovery (REC) training. Fasted blood samples were collected before and after exercise, on day 7 of each training week and were analyzed for plasma BDNF and cortisol concentrations. A 24-item Profile Of Mood State questionnaire was administered on day 7 of each training week and global mood score (GMS) was calculated. Results Time trial performance was impaired during INT (p=0.01) and REC (p=0.02) compared with NT. Basal plasma cortisol (NT=153±16 ng/ml, INT=130±11 ng/ml, REC=150±14 ng/ml) and BDNF (NT=484±122 pg/ml, INT=488±122 pg/ml, REC=383±56 pg/ml) concentrations were similar between training conditions. Likewise, similar exercise-induced increases in cortisol and BDNF concentrations were observed between training conditions. GMS was 32% greater during INTvs.NT (P<0.001). Conclusion Consistent with a state of functional overreaching (FOR), impairments in performance and mood state with INT were restored after one week of REC. These results support evidence that mood changes before plasma BDNF concentrations as a biochemical marker of FOR and that cortisol is not a useful marker for predicting FOR

Molecular Identification of Synanthedonini Members (Lepidoptera: Sesiidae) Using Cytochrome Oxidase I

Many North American sesiid moths within Synanthodonini have been studied extensively because their feeding activity can cause detrimental economic and esthetic impacts to many commercially important ornamental and native plant species. Recent discoveries of nonnative clearwing moth pest introductions [e.g., Synanthedon myopaeformis (Borkh.)], reinforce the need for reliable and accurate molecular diagnostic tools that can be used by nontaxonomic experts, particularly when juvenile life stages are recovered from infested host-plant tissues. Cytochrome oxidase I (cox I) previously has been used to successfully identify species and resolve species complexes. In this study, the cox I phylogeny inferred from sequences generated from 21 species of sesiid moths classified within Synanthedonini confirms the close evolutionary relationship between sesiid species. As other authors have suggested in previous works, we observed that Synanthedon rileyana H. Edwards appears atypical for the genus, as it paired with Carmenta bassiformis (Walker) one node removed from, but not sister to, a large well-supported Synanthedon-rich clade. Sannina uroceriformis Walker and Podosesia MXöschler were observed nested deeply within the aforementioned well-supported clade (posterior probability [PP] of clade = 100) comprised of all Synanthedon species sampled, except S. rileyana. Placement of these two taxa conflicts with results from previous morphological studies. These placements were immune from repeated attempts to delete perceived nearby long branches within the data set. Despite these few conflicts and overall low statistical support for most interspecific and higher relationships, our data suggest that all species examined possess unique genetic signatures that lend themselves to accurate identification of all life history stages of these clearwing pests