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  • Articles  (4)
  • Other Sources
  • Anastrepha ludens  (2)
  • Nitrogen fixation  (2)
  • Springer  (4)
  • AGU (American Geophysical Union)
  • Elsevier
  • 2015-2019
  • 1990-1994  (4)
  • Biology  (4)
  • Political Science
  • Physics
  • Architecture, Civil Engineering, Surveying
  • Electrical Engineering, Measurement and Control Technology
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  • Articles  (4)
  • Other Sources
Publisher
  • Springer  (4)
  • AGU (American Geophysical Union)
  • Elsevier
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Year
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  • Biology  (4)
  • Political Science
  • Physics
  • Architecture, Civil Engineering, Surveying
  • Electrical Engineering, Measurement and Control Technology
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  • 1
    ISSN: 1572-8889
    Keywords: mating behavior ; courtship ; lek ; mating system ; Mexican fruit fly ; Anastrepha ludens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mating behavior and factors affecting mating success of males were studied using wild Anastrepha ludens on a fieldcaged host tree. The most common courtship sequence had five components: (1) male calls from the underside of a leaf, (2) female arrives to the maleoccupied leaf, (3) male orients to female and stops calling, (4) one or both approach to a face-to-face position 1–3 cm apart, and (5) male mounts female after 1–2 s. Courtship behavior was almost identical to that of laboratoryculture flies observed previously under laboratory conditions. Most malefemale encounters occurred at a height of 1–2m, well inside the outer canopy of the tree. Differential mating success by males occurred. No male mated more than once per day, owing possibly to a very short sexual activity period. Factors favoring mating success of males were survival ability and tendency to join male aggregations and to fight other males. Thorax length and age (9–11 days difference) had no effects on male copulatory success. Overall win/loss percentage was not related to mating success because the males that were most successful at mating fought mostly among themselves, driving their win/loss percentage down. However, these successful males (at mating) won most of their fights against less successful males. Results confirmed a lek mating system: males aggregated, called, and defended territories; territories did not contain femalerequired resources; and females exercised mate choice, apparently through selection of sites within leks.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1617-4623
    Keywords: Nitrogen fixation ; Novel type of NifU ; Ethane formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DNA sequence analysis of a 3494-bp HindIII-Bc1I fragment of the Rhodobacter capsulatus nif region A revealed genes that are homologous to ORF6, nifU, nifS, nifV and nifW from Azotobacter vinelandii and Klebsiella pneumoniae. R. capsulatus nifU, which is present in two copies, encodes a novel type of NifU protein. The deduced amino acid sequences of NifUI and NifUII share homology only with the C-terminal domain of NifU from A. vinelandii and K. pneurnoniae. In contrast to nifA andnifB which are almost perfectly duplicated, the predicted amino acid sequences of the two NifU proteins showed only 39% sequence identity. Expression of the ORF6-nifU ISVW operon, which is preceded by a putative σ54-dependent promoter, required the function of NifA and the nif-specific rpoN gene product encoded by nifR4. Analysis of defined insertion and deletion mutants demonstrated that only nifS was absolutely essential for nitrogen fixation in R. capsulatus. Strains carrying mutations in nifV were capable of very slow diazotrophic growth, whereas ORF6, nifU I and nifW mutants as well as a nifU I/nifUII, double mutant exhibited a Nif+ phenotype. Interestingly, R. capsulatus nifV mutants were able to reduce acetylene not only to ethylene but also to ethane under conditions preventing the expression of the alternative nitrogenase system. Homocitrate added to the growth medium repressed ethane formation and cured the NifV phenotype in R. capsulatus. Higher concentrations of homocitrate were necessary to complement the NifV phenotype of a polar nifV mutant (NifV−NifW−), indicating a possible role of NifW either in homocitrate transport or in the incorporation of this compound into the iron-molybdenum cofactor of nitrogenase.
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  • 3
    ISSN: 1573-5079
    Keywords: Anabaena ; ferredoxin ; flavodoxin ; FPLC determination of ferredoxin and flavodoxin ; Iron deficiency ; Nitrogen fixation ; Photosynthesis ; strain differences in gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Iron-dependent formation of ferredoxin and flavodoxin was determined in Anabaena ATCC 29413 and ATCC 29211 by a FPLC procedure. In the first species ferredoxin is replaced by flavodoxin at low iron levels in the vegetative cells only. In the heterocysts from Anabaena ATCC 29151, however, flavodoxin is constitutively formed regardless of the iron supply. Replacement of ferredoxin by flavodoxin had no effect on photosynthetic electron transport, whereas nitrogen fixation was decreased under low iron conditions. As ferredoxin and flavodoxin exhibited the same Km values as electron donors to nitrogenase, an iron-limited synthesis of active nitrogenase was assumed as the reason for inhibited nitrogen fixation. Anabaena ATCC 29211 generally lacks the potential to synthesize flavodoxin. Under iron-starvation conditions, ferredoxin synthesis is limited, with a negative effect on photosynthetic oxygen evolution.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 16 (1990), S. 2799-2815 
    ISSN: 1573-1561
    Keywords: Attractants ; Mexican fruit fly ; Diptera ; Tephritidae ; Anastrepha ludens ; host fruit ; yellow chapote ; Rutaceae ; Sargentia greggii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Chemicals from fermented chapote fruit were identified and evaluated as attractants for hungry adult Mexican fruit flies in laboratory and greenhouse bioassays. Twenty-eight chemicals identified from an attractive gas-chromatography fraction were as attractive as a chapote volatiles extract (CV) when mixed in the same amounts found in CV. Sixteen of the chemicals were slightly attractive to flies when tested individually. A mixture containing 15 of the chemicals by design and the 16th as an impurity, in arbitrary concentrations, was at least as attractive as the original CV. In a series of experiments, the number of chemicals was reduced to three by elimination of unnecessary components. The three-component mixture retained the attractiveness of the 15-component mixture. The three chemicals were 1,8-cineole, ethyl hexanoate, and hexanol (CEH). Attractiveness of the three-chemical mixture was equal to the sum of the attractiveness of the three individual components, suggesting that each chemical binds to a different receptor type that independently elicits partial attraction behavior. Optimal ratios were 10∶1∶1 of the three chemicals, respectively. Optimal test quantities ranged between 0.4–4Μg of 1,8-cineole and 40–400 ng each of ethyl hexanoate and hexanol applied to filter paper in the laboratory bioassays. A neat 10∶1∶1 mixture of the chemicals was 1.8 times more attractive than aqueous solutions ofTorula dried yeast and borax to starved 2-day-old flies when the lures were tested in competing McPhail traps in a large greenhouse cage.
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