Patterns of population genetic structure and diversity across bumble bee communities in the Pacific Northwest

Patterns of genetic structure and diversity are largely mediated by a species’ ecological niche and sensitivity to climate variation. Some species with narrow ecological niches have been found to exhibit increased population differentiation, limited gene flow across populations, and reduced population genetic diversity. In this study, we examine patterns of population genetic structure and diversity of four bumble bee species that are broadly sympatric, but do not necessarily inhabit the same ecological niche in the Pacific Northwest of the United States. Testing for the effect of isolation by geographic distance (IBD) with linearized F _st and D _est found that Bombus sylvicola and B. mixtus exhibited significant IBD across populations. In contrast, both B. melanopygus and B. flavifrons, two species that are distributed across a broad elevation gradient, exhibited no IBD, a result further corroborated by Bayesian a priori population assignment tests. Furthermore, we discovered that B. sylvicola populations distributed on the Olympic Peninsula have significantly less average allelic diversity than populations distributed in the Cascade Mountains. Our results suggest that populations distributed in the Olympic Mountains represent a distinct genetic cluster relative to the Cascade Mountains, with B. sylvicola and B. mixtus likely experiencing the greatest degree of population genetic differentiation relative to B. flavifrons and B. melanopygus. While bumble bees are known to co-exist across a diversity of habitats, our results demonstrate that underlying population genetic structure and diversity may not necessarily be similar across species, and are largely governed by their respective niches.     

The Anopheles gambiae Odorant Binding Protein 1 (AgamOBP1) Mediates Indole Recognition in the Antennae of Female Mosquitoes

Haematophagous insects are frequently carriers of parasitic diseases, including malaria. The mosquito Anopheles gambiae is the major vector of malaria in sub-Saharan Africa and is thus responsible for thousands of deaths daily. Although the role of olfaction in A. gambiae host detection has been demonstrated, little is known about the combinations of ligands and odorant binding proteins (OBPs) that can produce specific odor-related responses in vivo. We identified a ligand, indole, for an A. gambiae odorant binding protein, AgamOBP1, modeled the interaction in silico and confirmed the interaction using biochemical assays. RNAi-mediated gene silencing coupled with electrophysiological analyses confirmed that AgamOBP1 binds indole in A. gambiae and that the antennal receptor cells do not respond to indole in the absence of AgamOBP1. This case represents the first documented instance of a specific A. gambiae OBP–ligand pairing combination, demonstrates the significance of OBPs in odor recognition, and can be expanded to the identification of other ligands for OBPs of Anopheles and other medically important insects.     

Program review. The Interdisciplinary Biophysics Graduate Program at the University of Michigan

The Michigan Biophysics Graduate Program (MBGP) was established in 1949, making it one of the first such programs in the world. The intellectual base of the program was significantly broadened in the 1980 when faculty members from a number of other units on campus were invited to join. Currently over forty faculty members from a variety of disciplines participate as mentors for the Ph.D. students enrolled in the MBGP providing our students with rich opportunities for academic learning and research. The MBGP has two main objectives: 1) to provide graduate students with both the intellectual and technical training in modern biophysics, 2) to sensitize our students to the power and unique opportunities of interdisciplinary work and thinking so as to train them to conduct research that crosses the boundaries between the biological and physical sciences. The program offers students opportunities to conduct research in a variety of areas of contemporary biophysics including structural biology, single molecule spectroscopy, spectroscopy and its applications, computational biology, membrane biophysics, neurobiophysics and enzymology. The MBGP offers a balanced curriculum that aims to provide our students with a strong academic base and, at the same time, accommodate their different academic backgrounds. Judging its past performance through the success of its former students, the MBGP has been highly successful, and there is every reason to believe that strong training in the biophysical sciences, as provided by the MBGP, will become even more valuable in the future both in the academic and the industrial settings. in the academic and the industrial settings.     

Quantitative Timed-Up-and-Go Parameters in Relation to Cognitive Parameters and Health-Related Quality of Life in Mild-to-Moderate Parkinson's Disease

IntroductionThe instrumented-Timed-Up-and-Go test (iTUG) provides detailed information about the following movement patterns: sit-to-walk (siwa), straight walking, turning and walk-to-sit (wasi). We were interested in the relative contributions of respective iTUG sub-phases to specific clinical deficits most relevant for daily life in Parkinson’s disease (PD). More specifically, we investigated which condition–fast speed (FS) or convenient speed (CS)–differentiates best between mild- to moderate-stage PD patients and controls, which parameters of the iTUG sub-phases are significantly different between PD patients and controls, and how the iTUG parameters associate with cognitive parameters (with particular focus on cognitive flexibility and working memory) and Health-Related-Quality of Life (HRQoL).MethodsTwenty-eight PD participants (65.1±7.1 years, H&Y stage 1–3, medication OFF state) and 20 controls (66.1±7.5 years) performed an iTUG (DynaPort^®, McRoberts BV, The Netherlands) under CS and FS conditions. The PD Questionnaire 39 (PDQ-39) was employed to assess HRQoL. General cognitive and executive functions were assessed using the Montreal Cognitive Assessment and the Trail Making Test.ResultsThe total iTUG duration and sub-phases durations under FS condition differentiated PD patients slightly better from controls, compared to the CS condition. The following sub-phases were responsible for the observed longer total duration PD patients needed to perform the iTUG: siwa, turn and wasi. None of the iTUG parameters correlated relevantly with general cognitive function. Turning duration and wasi maximum flexion velocity correlated strongest with executive function. Walking back duration correlated strongest with HRQoL.DiscussionThis study confirms that mild- to moderate-stage PD patients need more time to perform the iTUG than controls, and adds the following aspects to current literature: FS may be more powerful than CS to delineate subtle movement deficits in mild- to moderate-stage PD patients; correlation levels of intra-individual siwa and wasi parameters may be interesting surrogate markers for the level of automaticity of performed movements; and sub-phases and kinematic parameters of the iTUG may have the potential to reflect executive functioning and HRQoL aspects of PD patients.     

Über die röhrenförmige Nektarschuppe an den Nektarblättern verschiedenerRanunculus- undBatrachium-Arten

Zusammenfassung Nach einem Überblick über die Formenmannigfaltigkeit der rudimentären Ventralspreite, der Schuppe, der Nektarblätter vonRanunculus, wird an Hand vonRanunculus platanifolius undsceleratus sowieBatrachium trichophyllum versucht, den Bau der hufeisenförmigen und der geschlossenen ring- oder röhrenförmigen Nektarschuppe zu klären, da diese Schuppenformen nicht ohne weiteres aus dem Spreitenbau der an sich peltaten Nektarblätter verständlich sind.Die Untersuchung der Ontogenese und der Bündelversorgung der röhrenförmigen Nektarschuppen vonRanunculus platanifolius undBatrachium trichophyllum erwies sich dabei als nicht sehr aufschlußreich: der vordere Schuppenrand geht aus der Mitte einer basalen Verdickung der Blattanlage hervor, wächst seitlich empor und schließt nach einem hufeisenförmigen Zwischenstadium dann apikal zusammen; die vier Schuppenbündel vonRanunculus platanifolius, die dem Dorsalmedianus und einem Lateralis entspringen, bilden einen ventral offenen Bogen, beiBatrachium trichophyllum sind bloß zwei Bündel vorhanden, Äste des Dorsalmedianus, die aber bereits unterhalb des Nektargewebes endigen; die Orientierung der Schuppenbündel ist bei beiden Arten wegen der zarten Beschaffenheit nicht festzustellen.Die Lösung brachteRanunculus sceleratus, dessen Schuppenform normalerweise zwischen einem elliptischen Wall und einem oben offenen Hufeisen schwankt. Bei ihm wurden nämlich häufig Nektarblätter mit drei hufeisenförmigen Schuppenwällen gefunden, wobei die äußeren Randwülste der seitlichen Schuppen stets in den Spreitenrand übergingen. Zwischenformen zwischen verbildeten Antheren und Nektarblättern zeigten zudem ganz klar, daß diese Wülste selbst Teile des ventralen Spreitenrandes sind: die mit der Dorsalspreite kongenital verwachsene Ventralspreite ist median eingeschnitten und damit zweilappig, wie sie, freilich unverwachsen, ja auch bei verschiedenen Sapindaceen-Kronblättern anzutreffen ist; die basalen Randschleifen des medianen und der seitlichen (zwischen Dorsal- und Ventralspreite gelegenen) Einschnitte sind zu den drei Schuppenwällen verdickt. Da im Normalfall beiRanunculus undBatrachium der ventrale Spreitenrand seitlich in seiner Entwicklung gehemmt ist, bildet sich gewöhnlich nur die Randschleife des Medianeinschnittes zu einer normalen Nektarschuppe aus. Die Abrundung des von echten Randteilen gebildeten Hufeisenbogens zu einem ring- oder röhrenförmigen Gebilde aber erfolgt durch eine zusätzliche Neubildung, die mit dem Bau der Ventralspreite nichts zu tun hat.     

Vergleichende Untersuchungen an HNO2-Inaktivierten und UV-Inaktivierten Bakteriophagen T4

Summary The inactivation of phage T4 by nitrous acid (HNO₂) is essentially an exponential function of time of treatment. HNO₂-inactivated T4 is able to undergo multiplicity reactivation, and genetic markers may be rescued by live phage, however, the extent of both effects is appreciably less than after UV-inactivation. Also, the survival of phenotypic function of the cistronsr II-A andr II-B is lower with HNO₂-treatment than with a UV-irradiation of a corresponding number of hits.The reduced effects are quantitatively accounted for by the assumption of lethal hits blocking early steps of infection. These early-step damages amount to approximately 1/6 of the total hit number; it is still unknown whether they occur in DNA or in protein. Some indication for the occurrence in protein comes from the result that the host-killing efficiency of HNO₂-inactivated phage is reduced at a similar rate as these early-step damages occur. However, at least 5/6 of the lethal hits are due to chemical changes within the DNA, as can be calculated from the results of multiplicity reactivation, marker rescue, and phenotypic survival of therII-cistrons.

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NON-INFECTIOUS INFLAMMATORY AND NEOPLASTIC DISORDERS OF THE MALE GENITALIA

The cutaneous manifestations of the male external genitalia are difficult to diagnose. They may be associated with systemic disease (Reiter''s disease, psoriatic arthritis, angiokeratoma corporis diffusum). In dealing with a lesion of this area that does not heal, adequate biopsy is advisable to rule out malignant disease (Bowen''s disease, melanoma, Kaposi''s sarcoma, Paget''s disease, erythroplasia).     

Studies on the creeper fowl

Journal of Genetics -     

Three classes of ubiquinone analogs regulate the mitochondrial permeability transition pore through a common site

To identify the structural features required for regulation of the mitochondrial permeability transition pore (PTP) by ubiquinone analogs (Fontaine, E., Ichas, F., and Bernardi, P. (1998) J. Biol. Chem. 40, 25734-25740), we have carried out an analysis with quinone structural variants. We show that three functional classes can be defined: (i) PTP inhibitors (ubiquinone 0, decylubiquinone, ubiquinone 10, 2,3-dimethyl-6-decyl-1,4-benzoquinone, and 2,3,5-trimethyl-6-geranyl-1,4-benzoquinone); (ii) PTP inducers (2,3-dimethoxy-5-methyl-6-(10-hydroxydecyl)-1,4-benzoquinone and 2,5-dihydroxy-6-undecyl-1,4-benzoquinone); and (iii) PTP-inactive quinones that counteract the effects of both inhibitors and inducers (ubiquinone 5 and 2,3,5-trimethyl-6-(3-hydroxyisoamyl)-1,4-benzoquinone) . The structure-function correlation indicates that minor modifications in the isoprenoid side chain can turn an inhibitor into an activator, and that the methoxy groups are not essential for the effects of quinones on the PTP. Since the ubiquinone analogs used in this study have a similar midpoint potential and decrease mitochondrial production of reactive oxygen species to the same extent, these results support the hypothesis that quinones modulate the PTP through a common binding site rather than through oxidation-reduction reactions. Occupancy of this site can modulate the PTP open-closed transitions, possibly through secondary changes of the PTP Ca(2+) binding affinity.     

Effects of Elevated Atmospheric CO2 on Soil Microbial Biomass, Activity, and Diversity in a Chaparral Ecosystem

This study reports the effects of long-term elevated atmospheric CO₂ on root production and microbial activity, biomass, and diversity in a chaparral ecosystem in southern California. The free air CO₂ enrichment (FACE) ring was located in a stand dominated by the woody shrub Adenostoma fasciculatum. Between 1995 and 2003, the FACE ring maintained an average daytime atmospheric CO₂ concentration of 550 ppm. During the last two years of operation, observations were made on soil cores collected from the FACE ring and adjacent areas of chaparral with ambient CO₂ levels. Root biomass roughly doubled in the FACE plot. Microbial biomass and activity were related to soil organic matter (OM) content, and so analysis of covariance was used to detect CO₂ effects while controlling for variation across the landscape. Extracellular enzymatic activity (cellulase and amylase) and microbial biomass C (chloroform fumigation-extraction) increased more rapidly with OM in the FACE plot than in controls, but glucose substrate-induced respiration (SIR) rates did not. The metabolic quotient (field respiration over potential respiration) was significantly higher in FACE samples, possibly indicating that microbial respiration was less C limited under high CO₂. The treatments also differed in the ratio of SIR to microbial biomass C, indicating a metabolic difference between the microbial communities. Bacterial diversity, described by 16S rRNA clone libraries, was unaffected by the CO₂ treatment, but fungal biomass was stimulated. Furthermore, fungal biomass was correlated with cellulase and amylase activities, indicating that fungi were responsible for the stimulation of enzymatic activity in the FACE treatment.