| 1. |
- Löfstedt, Christer, et al.
(författare)
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Pheromonal secretions from glands on the 5th abdominal sternite of hydropsychid and rhyacophilid caddisflies (Trichoptera)
- 1994
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Ingår i: Journal of Chemical Ecology. - 0098-0331. ; 20:1, s. 153-170
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Tidskriftsartikel (refereegranskat)abstract
- Extracts of different body parts of adult Trichoptera were tested for electrophysiological activity. Extracts of the IVth and Vth abdominal sternites of female Hydropsyche angustipennis, Rhyacophila nubila, and R. fasciata, containing a paired exocrine gland, elicited significant electroan-tennographic responses when tested on conspecific male antennae. The paired gland occurs also in males of all the species, and in H. angustipennis, extracts from males were more active than female extracts when tested on male antennae. Female and male extracts from all species were analyzed by gas chromatography with simultaneous flame ionization and electroantennographic detection (EAD). EAD-active peaks in female extracts, stimulating male antennae, were identified in H. angustipennis as nonan-2-one; and in R. nubila and R. fasciata as heptan-2-one, heptan-2-ol, nonan-2-one, and nonan-2-ol. EAD-active components from male H. angustipennis stimulating male antennae were octan-2-one, nonan-2-one (major peak), (Z)-6-nonen-2-one, decan-2-one, and a methylbranched decan-2-one. Female extracts and synthetic mixtures of compounds identified from female H. angustipennis and R. fasciata were tested for attractivity in the field. High catches with control traps obscured the results, but a synthetic mixture of the four identified compounds was significantly attractive and not different from female extracts for attracting male R. fasciata. In H. angustipennis, a synthetic six-component male blend, in which nonan-2-one was the major component, attracted significant numbers of male and female H. angustipennis. Extracts of male R. nubila and R. fasciata contained acetophenone and hexanoic and octanoic acids but did not have any electrophysiological or behavioral activity on either male or female antennae of conspecifics. The occurrence of a female sex pheromone in Rhyacophila and an aggregation pheromone in Hydropsyche corresponds to earlier described differences in mating behaviors in the Rhyacophilidae and Hydropsychidae.
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| 2. |
- Antuch, W, et al.
(författare)
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The NMR solution structure of a Kunitz-type proteinase inhibitor from the sea anemone Stichodactyla helianthus.
- 1993
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Ingår i: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 212, s. 675-684
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Tidskriftsartikel (refereegranskat)abstract
- The solution structure of a 55-amino-acid Kunitz-type proteinase inhibitor, ShPI, purified from the Caribbean sea anemone Stichodactyla helianthus, was determined by NMR spectroscopy. Nearly complete sequence-specific 1H-NMR assignments were obtained at pH 4.6 and 36 degrees C, and stereo-specific assignments were determined for 23 pairs of diastereotopic substituents. A data set of 666 upper distance limit constraints and 122 dihedral angle constraints collected on this basis was used as input for a structure calculation with the program DIANA. Following energy minimization with the program OPAL, the average root-mean-square diviation (RMSD) of the 20 DIANA conformers used to represent the solution structure relative to the mean structure is 61 pm for all backbone atoms N, C alpha and C', and 106 pm for all heavy atoms of residues 2-53. This high-quality solution structure of ShPI has a nearly identical molecular architecture as the bovine pancreatic trypsin inhibitor (BPTI), despite a mere 35% of sequence similarity between the two proteins. Exchange rates measured for 48 out of the 51 backbone amide protons showed that the positions of 20 slowly exchanging amide protons correlate well with hydrogen bonds involving these protons in the energy-minimized solution structure. The solution structure of ShPI is compared to the four homologous proteins for which the three-dimensional structure is also available.
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| 3. |
- Berndt, Kurt D, et al.
(författare)
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Designed replacement of an internal hydration water molecule in BPTI : structural and functional implications of a glycine-to-serine mutation.
- 1993
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 32, s. 4564-4570
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Tidskriftsartikel (refereegranskat)abstract
- The three-dimensional structure of the basic pancreatic trypsin inhibitor (BPTI) contains four internal water molecules, which form a total of nine intermolecular hydrogen bonds with the BPTI polypeptide chain. To investigate the effect of such internal hydration on protein structure and stability, we displaced one of the internal water molecules in a recombinant BPTI analogue, BPTI(G36S), in which Gly 36 is replaced by serine. The replacement of a water molecule by the seryl side chain was established by the absence of the protein-water nuclear Overhauser effects (NOE) that had been attributed to the water molecule near Gly 36 in wild-type BPTI and by the presence of new, intramolecular NOEs to the hydroxyl proton of Ser 36. BPTI(G36S) has slightly reduced thermal stability compared to BPTI, corresponding to a destabilization by delta (delta G) approximately 0.7 kcal/M in 6 M guanidinium hydrochloride solution. Additionally, the stabilities of the complexes formed between BPTI(G36S) and trypsin, plasmin, or kallikrein are significantly reduced when compared to the corresponding complexes with wild-type BPTI.
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| 4. |
- Berndt, Kurt D, et al.
(författare)
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Determination of a high-quality nuclear magnetic resonance solution structure of the bovine pancreatic trypsin inhibitor and comparison with three crystal structures
- 1992
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Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836. ; 227, s. 757-775
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Tidskriftsartikel (refereegranskat)abstract
- A high-quality three-dimensional structure of the bovine pancreatic trypsin inhibitor (BPTI) in aqueous solution was determined by 1H nuclear magnetic resonance (n.m.r.) spectroscopy and compared to the three available high-resolution X-ray crystal structures. A newly collected input of 642 distance constraints derived from nuclear Overhauser effects and 115 dihedral angle constraints was used for the structure calculations with the program DIANA, followed by restrained energy minimization with the program AMBER. The BPTI solution structure is represented by a group of 20 conformers with an average root-mean-square deviation (RMSD) relative to the mean solution structure of 0.43 A for backbone atoms and 0.92 A for all heavy atoms of residues 2 to 56. The pairwise RMSD values of the three crystal structures relative to the mean solution structure are 0.76 to 0.85 A for the backbone atoms and 1.24 to 1.33 A for all heavy atoms of residues 2 to 56. Small local differences in backbone atom positions between the solution structure and the X-ray structures near residues 9, 25 to 27, 46 to 48 and 52 to 58, and conformational differences for individual amino acid side-chains were analyzed for possible correlations with intermolecular protein-protein contacts in the crystal lattices, using the pairwise RMSD values among the three crystal structures as a reference.
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| 5. |
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| 6. |
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| 7. |
- Güntert, P, et al.
(författare)
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The Program Asno for Computer-Supported Collection of Noe Upper Distance Constraints as Input for Protein-Structure Determination
- 1993
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Ingår i: Journal of Biomolecular NMR. - 0925-2738 .- 1573-5001. ; 3:5, s. 601-606
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Tidskriftsartikel (refereegranskat)abstract
- A new program, ASNO ('ASsign NOes'), for computer-supported NOE cross-peak assignments is described. ASNO is used for structure refinement in several rounds of NOESY cross-peak assignments and 3D structure calculations, where the preliminary structures are used as a reference to resolve ambiguities in NOE assignments which are otherwise based on the chemical shifts available from the sequence-specific resonance assignments. The practical use of ASNO for proteins is illustrated with the structure determination of Dendrotoxin K from Dendroaspis polylepis polylepis.
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| 8. |
- Hansson, B. S., et al.
(författare)
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Correlation between dendrite diameter and action potential amplitude in sex pheromone specific receptor neurons in male Ostrinia nubilalis (Lepidoptera: Pyralidae)
- 1994
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Ingår i: Tissue and Cell. - : Elsevier BV. - 0040-8166. ; 26:4, s. 503-512
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Tidskriftsartikel (refereegranskat)abstract
- Outer dendritic segments of olfactory receptor neurons tuned to sex pheromone components were measured morphometrically on the antenna of male European corn borers. Ostrinia nubilalis, to determine if a correlation exists between the diameter of the outer dendritic segment and the spike amplitude. The olfactory sensilla investigated each contained three receptor cells. Two cells were each specific for one of the two pheromone components, (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (E)-11-tetradecenyl acetate (E11-14:OAc). Two strains of cornborers (Z and E) differ as to which of the two pheromone components is the main one. In both strains a large difference could be observed between the spike amplitudes elicited in the receptor cells by the two pheromone components, the main component always eliciting the large spike. In F1-hybrids (EZ) of these two strains, producing both pheromone components in similar quantities, the spike amplitudes were equal in the two pheromone-specific receptor cells. The third cell responded specifically to a behavioural antagonist. (Z)-9-tetradecenyl acetate (Z9-14:OAc) in both the parental and hybrid strains, and always showed the smallest spike amplitude. In a morphometric study, the outer dendritic segments were shown to differ more in diameter between the largest and second largest cell in the two parental strains than in the hybrid strain, while the smallest diameter cell did not differ between the different strains. These results imply that receptor cells with larger diameter produce spikes with greater amplitude. The data also show that all three types of receptor neurons display outer dendritic segments with strong variation in the diameter along the length of the segment, and with a pronounced taper towards the tip.
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| 9. |
- Hansson, Bill S., et al.
(författare)
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Functional specialization of olfactory glomeruli in a moth
- 1992
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Ingår i: Science. - 0036-8075. ; 256:5061, s. 1313-1315
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Tidskriftsartikel (refereegranskat)abstract
- The specific function of the glomerular structures present in the antennal lobes or olfactory bulbs of organisms ranging from insects to humans has been obscure because of limitations in neuronal marking methods. By tracing individual neurons in the moth Agrotis segetum, it was determined that physiologically distinct types of pheromone receptor neurons project axons to different regions of the macroglomerular complex (MGC). Each glomerulus making up the MGC has a specific functional identity, initially processing information about one specific pheromone component. This indicates that, at least through the first stage of synapses, olfactory information moves through labeled lines.
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| 10. |
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