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  • 1
    Publication Date: 2016-03-26
    Description: Polarization maintaining optical fibers can be used to transmit linearly polarized light over long distances but their use in cryogenic environments has been limited by their sensitivity to temperature changes and associated mechanical stress. We investigate experimentally how thermal stresses affect the polarization maintaining fibers and model the observations with Jones matrices. We describe the design, construction, and testing of a feedthrough and fiber termination assembly that uses polarization maintaining fiber to transmit light from a 633 nm HeNe laser at room temperature to a homodyne polarization-based interferometer in a cryogenic vacuum. We report on the efficiency of the polarization maintaining properties of the feedthrough assembly. We also report that, at cryogenic temperatures, the interferometer can achieve a sensitivity of 8 × 10 −10 rad/ Hz at 0.05 Hz using this feedthrough.
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
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  • 2
    Publication Date: 2012-01-24
    Description: Hypertension affects one billion people and is a principal reversible risk factor for cardiovascular disease. Pseudohypoaldosteronism type II (PHAII), a rare Mendelian syndrome featuring hypertension, hyperkalaemia and metabolic acidosis, has revealed previously unrecognized physiology orchestrating the balance between renal salt reabsorption and K(+) and H(+) excretion. Here we used exome sequencing to identify mutations in kelch-like 3 (KLHL3) or cullin 3 (CUL3) in PHAII patients from 41 unrelated families. KLHL3 mutations are either recessive or dominant, whereas CUL3 mutations are dominant and predominantly de novo. CUL3 and BTB-domain-containing kelch proteins such as KLHL3 are components of cullin-RING E3 ligase complexes that ubiquitinate substrates bound to kelch propeller domains. Dominant KLHL3 mutations are clustered in short segments within the kelch propeller and BTB domains implicated in substrate and cullin binding, respectively. Diverse CUL3 mutations all result in skipping of exon 9, producing an in-frame deletion. Because dominant KLHL3 and CUL3 mutations both phenocopy recessive loss-of-function KLHL3 mutations, they may abrogate ubiquitination of KLHL3 substrates. Disease features are reversed by thiazide diuretics, which inhibit the Na-Cl cotransporter in the distal nephron of the kidney; KLHL3 and CUL3 are expressed in this location, suggesting a mechanistic link between KLHL3 and CUL3 mutations, increased Na-Cl reabsorption, and disease pathogenesis. These findings demonstrate the utility of exome sequencing in disease gene identification despite the combined complexities of locus heterogeneity, mixed models of transmission and frequent de novo mutation, and establish a fundamental role for KLHL3 and CUL3 in blood pressure, K(+) and pH homeostasis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3278668/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3278668/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Boyden, Lynn M -- Choi, Murim -- Choate, Keith A -- Nelson-Williams, Carol J -- Farhi, Anita -- Toka, Hakan R -- Tikhonova, Irina R -- Bjornson, Robert -- Mane, Shrikant M -- Colussi, Giacomo -- Lebel, Marcel -- Gordon, Richard D -- Semmekrot, Ben A -- Poujol, Alain -- Valimaki, Matti J -- De Ferrari, Maria E -- Sanjad, Sami A -- Gutkin, Michael -- Karet, Fiona E -- Tucci, Joseph R -- Stockigt, Jim R -- Keppler-Noreuil, Kim M -- Porter, Craig C -- Anand, Sudhir K -- Whiteford, Margo L -- Davis, Ira D -- Dewar, Stephanie B -- Bettinelli, Alberto -- Fadrowski, Jeffrey J -- Belsha, Craig W -- Hunley, Tracy E -- Nelson, Raoul D -- Trachtman, Howard -- Cole, Trevor R P -- Pinsk, Maury -- Bockenhauer, Detlef -- Shenoy, Mohan -- Vaidyanathan, Priya -- Foreman, John W -- Rasoulpour, Majid -- Thameem, Farook -- Al-Shahrouri, Hania Z -- Radhakrishnan, Jai -- Gharavi, Ali G -- Goilav, Beatrice -- Lifton, Richard P -- KL2 RR024138/RR/NCRR NIH HHS/ -- KL2 RR024138-07/RR/NCRR NIH HHS/ -- P30 DK079310/DK/NIDDK NIH HHS/ -- P30 DK079310-04S1/DK/NIDDK NIH HHS/ -- P30-DK079310/DK/NIDDK NIH HHS/ -- UL1-RR024139/RR/NCRR NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2012 Jan 22;482(7383):98-102. doi: 10.1038/nature10814.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Genetics and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22266938" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Blood Pressure/genetics ; Carrier Proteins/chemistry/*genetics ; Cohort Studies ; Cullin Proteins/chemistry/*genetics ; Electrolytes ; Exons/genetics ; Female ; Gene Expression Profiling ; Genes, Dominant/genetics ; Genes, Recessive/genetics ; Genotype ; Homeostasis/genetics ; Humans ; Hydrogen-Ion Concentration ; Hypertension/complications/*genetics/physiopathology ; Male ; Mice ; Models, Molecular ; Molecular Sequence Data ; Mutation/*genetics ; Phenotype ; Potassium/metabolism ; Pseudohypoaldosteronism/complications/*genetics/physiopathology ; Sodium Chloride/metabolism ; Water-Electrolyte Imbalance/complications/*genetics/physiopathology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2013-12-20
    Description: Nucleosomes are decorated with numerous post-translational modifications capable of influencing many DNA processes. Here we describe a new class of histone modification, methylation of glutamine, occurring on yeast histone H2A at position 105 (Q105) and human H2A at Q104. We identify Nop1 as the methyltransferase in yeast and demonstrate that fibrillarin is the orthologue enzyme in human cells. Glutamine methylation of H2A is restricted to the nucleolus. Global analysis in yeast, using an H2AQ105me-specific antibody, shows that this modification is exclusively enriched over the 35S ribosomal DNA transcriptional unit. We show that the Q105 residue is part of the binding site for the histone chaperone FACT (facilitator of chromatin transcription) complex. Methylation of Q105 or its substitution to alanine disrupts binding to FACT in vitro. A yeast strain mutated at Q105 shows reduced histone incorporation and increased transcription at the ribosomal DNA locus. These features are phenocopied by mutations in FACT complex components. Together these data identify glutamine methylation of H2A as the first histone epigenetic mark dedicated to a specific RNA polymerase and define its function as a regulator of FACT interaction with nucleosomes.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3901671/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3901671/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tessarz, Peter -- Santos-Rosa, Helena -- Robson, Sam C -- Sylvestersen, Kathrine B -- Nelson, Christopher J -- Nielsen, Michael L -- Kouzarides, Tony -- 092096/Wellcome Trust/United Kingdom -- A10827/Cancer Research UK/United Kingdom -- BB/K017438/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- England -- Nature. 2014 Jan 23;505(7484):564-8. doi: 10.1038/nature12819. Epub 2013 Dec 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK [2] Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK. ; Department of Proteomics, The Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark. ; 1] Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK [2] Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK [3] Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24352239" target="_blank"〉PubMed〈/a〉
    Keywords: Alanine/genetics/metabolism ; Amino Acid Motifs ; Amino Acid Sequence ; Binding Sites ; Cell Nucleolus/metabolism ; Chromatin/genetics ; Chromosomal Proteins, Non-Histone/metabolism ; DNA, Ribosomal/genetics ; Epistasis, Genetic ; Glutamine/*metabolism ; Histones/*chemistry/*metabolism ; Humans ; Methylation ; Methyltransferases/metabolism ; Molecular Chaperones/metabolism ; Molecular Sequence Data ; Multiprotein Complexes/metabolism ; Nuclear Proteins/metabolism ; Nucleosomes/metabolism ; Protein Binding ; Protein Processing, Post-Translational ; RNA/metabolism ; RNA Polymerase I/*metabolism ; Ribonucleoproteins, Small Nucleolar/metabolism ; Saccharomyces cerevisiae/enzymology/genetics/metabolism ; Saccharomyces cerevisiae Proteins/metabolism ; Substrate Specificity ; Transcription, Genetic
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 71 (1987), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Fructans are a major form of stored carbohydrate in vegetative tissues of many plant species and may contribute other functions. Their chemical structures, distribution among plant families, metabolism and possible physiological significance are discussed.
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  • 5
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THE data in this letter were gathered at Arecibo Observatory1 using the incoherent backscatter technique2. Observations were made during the March 7, 1970, eclipse and on March 6 and March 8 as control days. The observations were made in two modes summarized in Table 1: one mode combining plasma ...
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  • 6
    ISSN: 1573-1561
    Keywords: Danaus plexippus ; Lepidoptera ; Danaidae ; monarch butterflies ; Asdepias speciosa ; Asclepiadaceae ; milkweeds ; ecological chemistry ; plant-insect interactions ; chemical ecology ; chemical defense ; coevolution ; thin-layer chromatography ; cardenolide fingerprints ; cardenolides ; cardiac glycosides ; desglucosyrioside ; labriformin ; labriformidin ; syriogenin ; uzarigenin ; emetic potency ; emesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The pattern of variation in gross cardenolide concentration of 111Asclepias speciosa plants collected in six different areas of California is a positively skewed distribution which ranges from 19 to 344 μg of cardenolide per 0.1 g dry weight with a mean of 90 μg per 0.1 g. Butterflies reared individually on these plants in their native habitats ranged from 41 to 547 μg of cardenolide per 0.1 g dry weight with a mean of 179 μg. Total cardenolide per butterfly ranged from 54 to 1279 μg with a mean of 319 μg. Differences in concentrations and total cardenolide contents in the butterflies from the six geographic areas appeared minor, and there were no differences between the males and the females, although the males did weigh significantly more than females. The uptake of cardenolide by the butterflies was found to be a logarithmic function of the plant concentration. This results in regulation: larvae which feed on low-concentration plants produce butterflies with increased cardenolide concentrations relative to those of the plants, and those which feed on high-concentration plants produce butterflies with decreased concentrations. No evidence was adduced that high concentrations of cardenolides in the plants affected the fitness of the butterflies. The mean emetic potencies of the powdered plant and butterfly material were 5.62 and 5.25 blue jay emetic dose fifty units per milligram of cardenolide and the number of ED50 units per butterfly ranged from 0.28 to 6.7 with a mean of 1.67. Monarchs reared onA. speciosa, on average, are only about one tenth as emetic as those reared onA. eriocarpa. UnlikeA. eriocarpa which is limited to California,A. speciosa ranges from California to the Great Plains and is replaced eastwards byA. syriaca L. These two latter milkweed species appear to have a similar array of chemically identical cardenolides, and therefore both must produce butterflies of relatively low emetic potency to birds, with important ecological implications. About 80% of the lower emetic potency of monarchs reared on A. speciosa compared to those reared onA. eriocarpa appears attributable to the higher polarity of the cardenolides inA. speciosa. Thin-layer Chromatographie separation of the cardenolides in two different solvent systems showed that there are 23 cardenolides in theA. speciosa plants of which 20 are stored by the butterflies. There were no differences in the cardenolide spot patterns due either to geographic origin or the sex of the butterflies. As when reared onA. eriocarpa, the butterflies did not store the plant cardenolides withR f values greater than digitoxigenin. However, metabolic transformation of the cardenolides by the larvae appeared minor in comparison to when they were reared onA. eriocarpa. AlthoughA. eriocarpa andA. speciosa contain similar numbers of cardenolides and both contain desglucosyrioside, the cardenolides ofA. speciosa overall are more polar. ThusA. speciosa has no or only small amounts of the nonpolar labriformin and labriformidin, whereas both occur in high concentrations inA. eriocarpa. A. speciosa plants and butterflies also contain uzarigen, syriogenin, and possibly other polar cardenolides withR f values lower than digitoxin. The cardenolide concentration in the leaves is not only considerably less than inA. eriocarpa, but the latex has little to immeasurable cardenolide, whereas that ofA. eriocarpa has very high concentrations of several cardenolides. Quantitative analysis ofR f values of the cardenolide spots, their intensities, and their probabilities of occurrence in the chloroform-methanol-formamide TLC system produced a cardenolide fingerprint pattern very different from that previously established for monarchs reared onA. eriocarpa. This dispels recently published skepticism about the predictibility of chemical fingerprints based upon ingested secondary plant chemicals.
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  • 7
    ISSN: 1573-1561
    Keywords: Danaus plexippus ; monarch butterflies ; Lepidoptera ; Danaidae ; Asclepiadaceae ; milkweeds ; Asclepias syriaca ; Asclepias speciosa ; ecological chemistry ; chemical defense ; cardenolides ; aspecioside ; desglucosyrioside ; syriobioside ; overwintering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The majority (85%) of 394 monarch butterflies sampled from overwintering sites in Mexico contain the same epoxy cardenolide glycosides, including most conspicuously a novel polar glycoside with a single genin-sugar bridge (aspecioside), as occur in the milkweedsAsclepias speciosa andA. syriaca. This cardenolide commonality was established by isolating aspecioside and syriobioside from the wings of overwintering monarchs and the two plant species, and comparing Chromatographie and NMR spectrometric characteristics of the isolates. When combined with the migratory pattern of monarchs and the distribution of these two milkweed species, this chemical evidence lends strong support to the hypothesis thatA. syriaca is the major late summer food plant of monarchs in eastern North America. This finding may be of ecological importance, forA. syriaca contributes less cardenolide and cardenolides of lower emetic potency to monarchs than most milkweeds studied to date.
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  • 8
    ISSN: 1573-1561
    Keywords: Asclepias eriocarpa ; Asclepiadaceae ; milkweed ; cardenolides ; chemical defense ; chemical ecology ; labriformin ; labriformidin ; desglucosyrioside ; uzarigenin ; variation ; season ; plant part ; defense ; root ; stem ; leaf ; latex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Root, stem, leaf, and latex samples ofAsclepias eriocarpa collected from three plots in one population at 12 monthly intervals were assayed for total cardenolide content by spectroassay and for individual cardenolides by thin-layer chromatography. From May to September mean milligram equivalents of digitoxin per gram of dried plant were: latices, 56.8 ≫ stems, 6.12 〉 leaves, 4.0 〉 roots, 2.5. With the exception of the roots, significant changes in gross cardenolide content occurred for each sample type with time of collection during the growing season, whereas variation within this population was found to be small. Labriformin, a nitrogen-containing cardenolide of low polarity, predominated in the latices. Leaf samples contained labriformin, labriformidin, desglucosyrioside, and other unidentified cardenolides. In addition to most of the same cardenolides as the leaves, the stems also contained uzarigenin. The roots contained desglucosyrioside and several polar cardenolides. The results are compared with those for other cardenolide-containing plants, and discussed in relation to anti-herbivore defense based on plant cardenolide content. Arguments are advanced for a central role of the latex in cardenolide storage and deployment which maximizes the defensive qualities of the cardenolides while preventing toxicity to the plant.
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  • 9
    ISSN: 1573-1561
    Keywords: Danaus plexippus ; Danaidae ; monarch butterflies ; Asclepias eriocarpa ; Asclepiadaceae ; milkweeds ; coevolution ; thin-layer chromatography ; glycosides ; cardenolides ; cardenolide fingerprints ; chemical defense ; chemical ecology ; labriformin ; labriformidin ; desglucosyrioside ; emesis ; ecological chemistry ; plant-insect interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract This paper is the first in a series on cardenolide fingerprinting of the monarch butterfly. New methodologies are presented which allow both qualitative and quantitative descriptions of the constituent cardenolides which these insects derive in the wild from specificAsclepias foodplants. Analyses of thin-layer Chromatographic profiles ofAsclepias eriocarpa cardenolides in 85 individual plant-butterfly pairs collected at six widely separate localities in California indicate a relatively invariant pattern of 16–20 distinct cardenolides which we here define as theAsclepias eriocarpa cardenolide fingerprint profile. Cardenolide concentrations vary widely in the plant samples, but monarchs appear able to regulate total storage by increasing their concentrations relative to their larval host plant when reared on plants containing low concentrations, and vice versa. Forced-feeding of blue jays with powdered butterfly and plant material and with one of the constituent plant cardenolides, labriformin, established that theA. eriocarpa cardenolides are extremely emetic, and that monarchs which have fed on this plant contain an average of 16 emetic-dose fifty (ED50) units. The relatively nonpolar labriformin and labriformidin in the plant are not stored by the monarch but are metabolized in vivo to desglucosyrioside which the butterfly does store. This is chemically analogous to the way in which monarchs and grasshoppers metabolize another series of milkweed cardenolides, those found inA. curassavica. It appears that the sugar moiety through functionality at C-3′ determines which cardenolides are metabolized and which are stored. The monarch also appears able to store several lowR f cardenolides fromA. eriocarpa without altering them. Differences in the sequestering process in monarchs and milkweed bugs (Oncopeltus) may be less than emphasized in the literature. The monarch is seen as a central organism involved in a coevolutionary triad simultaneously affecting and affected by both its avian predators and the secondary chemistry of the milkweeds with which it is intimately involved.
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  • 10
    ISSN: 1573-1561
    Keywords: Danaus plexippus ; Lepidoptera ; Danaidae ; monarch butterflies ; Asclepias californica ; Asclepiadaceae ; milkweeds ; ecological chemistry ; plant-insect interactions ; chemical ecology ; chemical defense ; chemotaxonomy ; coevolution ; thin-layer chromatography ; cardenolide fingerprints ; cardenolides ; calotropagenin glycosides ; calactin ; calotropin ; uscharidin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Variation in gross cardenolide concentration of the mature leaves of 85Asclepias californica plants collected in four different areas of California is a positively skewed distribution ranging from 9 to 199 μg of cardenolide per 0.1 g dry weight with a mean of 66 μg/0.1 g. Butterflies reared individually on these plants in their native habitats contained a normal distribution of cardenolide ranging from 59 to 410 μg of cardenolide per 0.1 g dry weight with a mean of 234 μg. Cardenolide uptake by the butterflies was a logarithmic function of plant concentration. Total cardenolide per butterfly ranged from 143 to 823 μg with a mean of 441 μg and also was normally distributed. Populational variation of plant cardenolide concentrations occurs within subspecies, but the northern subspeciesA. c. greenei does not differ significantly from the southernA. c. californica. Generally higher concentrations occur in butterflies from northern populations and in females. No evidence was adduced that cardenolides in the plants adversely affected the butterflies. Low cardenolide concentrations in the leaves and the absence of cardenolides in the latex characterize bothA. californica andA. speciosa, but notA. eriocarpa. Thin-layer chromatography in two solvent systems isolated 24 cardenolide spots in the plants, of which 18 are stored by the butterflies. There was a minor difference in the cardenolide spot patterns due to geographic origin of the plants, but as in our previous studies, none in the sexes of the butterflies. UnlikeA. eriocarpa andA. speciosa, A. californica plants lack cardenolides withRf values greater than digitoxigenin. Overall, the cardenolides of bothA. californica andA. speciosa are more polar than those inA. eriocarpa. A. californica plants contain cardenolides of the calotropagenin series including calotropin, calactin, and uscharidin, and the latter is metabolically transformed by monarch larvae to calactin and calotropin. Cardenolides of this series also occur inA. vestita, andA. cordifolia from California, the neotropicalA. curassavica, and the AfricanCalotropis procera, Gomphocarpus spp., andPergularia extenso; they therefore cross established taxonomic lines.A. californica is the predominant early season milkweed in California and may be important in providing chemical protection to the spring generation of monarchs in the western United States.A. speciosa, A. eriocarpa, andA. californica each imparts distinctive cardenolide fingerprints to the butterflies, so that ecological predictions are amenable to testing.
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