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81.
Assessment of the potential of Napier grass (Pennisetum purpureum) varieties as trap plants for management of Chilo partellus 总被引:1,自引:0,他引:1
Zeyaur R. Khan Charles A.O. Midega Nicholas J. Hutter Richard M. Wilkins & Lester J. Wadhams 《Entomologia Experimentalis et Applicata》2006,119(1):15-22
Ten Napier grass [Pennisetum purpureum Schumach (Poaceae)] varieties, used in various parts of Kenya as animal fodder, were tested for their potential role as a trap crop in the management of the gramineous spotted stemborer, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), through habitat manipulation. Oviposition preference and larval survival and development were determined for each of these varieties under laboratory and screen‐house conditions. Two‐choice tests revealed that seven of the varieties tested were preferentially chosen by gravid female moths for oviposition over a susceptible maize cv. Inbred A. Larval survival was significantly lower on the majority of the Napier grass varieties (about 10%) than on maize cv. Inbred A (about 60%). Similarly, larval development was about 2 weeks longer on the majority of the Napier grass varieties. It was concluded that four of the varieties tested (Bana, Ex‐Machakos, Gold Coast, and Ex‐Nyanza‐2) had potential for use as trap crops in C. partellus management because they were more preferred by the borer moths for oviposition and allowed minimal survival of the larvae. This minimal larval survival is desirable in the conservation of C. partellus natural enemies when the cultivated host plant is out of season. 相似文献
82.
Characterization of the cytochrome c oxidase in isolated and purified plasma membranes from the cyanobacterium Anacystis nidulans 总被引:4,自引:0,他引:4
Functionally intact plasma membranes were isolated from the cyanobacterium (blue-green alga) Anacystis nidulans through French pressure cell extrusion of lysozyme/EDTA-treated cells, separated from thylakoid membranes by discontinuous sucrose density gradient centrifugation, and purified by repeated recentrifugation. Origin and identity of the chlorophyll-free plasma membrane fraction were confirmed by labeling of intact cells with impermeant protein markers, [35S]diazobenzenesulfonate and fluorescamine, prior to membrane isolation. Rates of oxidation of reduced horse heart cytochrome c by purified plasma and thylakoid membranes were 90 and 2 nmol min-1 (mg of protein)-1, respectively. The cytochrome oxidase in isolated plasma membranes was identified as a copper-containing aa3-type enzyme from the properties of its redox-active and EDTA-resistant Cu2+ ESR signal, the characteristic inhibition profile, reduced minus oxidized difference spectra, carbon monoxide difference spectra, photoaction and photodissociation spectra of the CO-inhibited enzyme, and immunological cross-reaction of two subunits of the enzyme with antibodies against subunits I and II, and the holoenzyme, of Paracoccus denitrificans aa3-type cytochrome oxidase. The data presented are the first comprehensive evidence for the occurrence of aa3-type cytochrome oxidase in the plasma membrane of a cyanobacterium similar to the corresponding mitochondrial enzyme (EC 1.9.3.1). 相似文献
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Stefanie M. Hixson Kruti Shukla Lesley G. Campbell Rebecca H. Hallett Sandy M. Smith Laurence Packer Michael T. Arts 《PloS one》2016,11(3)
Nutritional enhancement of crops using genetic engineering can potentially affect herbivorous pests. Recently, oilseed crops have been genetically engineered to produce the long-chain omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) at levels similar to that found in fish oil; to provide a more sustainable source of these compounds than is currently available from wild fish capture. We examined some of the growth and development impacts of adding EPA and DHA to an artificial diet of Pieris rapae, a common pest of Brassicaceae plants. We replaced 1% canola oil with EPA: DHA (11:7 ratio) in larval diets, and examined morphological traits and growth of larvae and ensuing adults across 5 dietary treatments. Diets containing increasing amounts of EPA and DHA did not affect developmental phenology, larval or pupal weight, food consumption, nor larval mortality. However, the addition of EPA and DHA in larval diets resulted in progressively heavier adults (F 4, 108 = 6.78; p = 0.011), with smaller wings (p < 0.05) and a higher frequency of wing deformities (R = 0.988; p = 0.001). We conclude that the presence of EPA and DHA in diets of larval P. rapae may alter adult mass and wing morphology; therefore, further research on the environmental impacts of EPA and DHA production on terrestrial biota is advisable. 相似文献
86.
D. J. Wolff Karen M. Gustashaw Vickie Zurcher Lara Ko Wendy White Lester Weiss Daniel L. Van Dyke Stuart Schwartz Huntington F. Willard 《Human genetics》1997,100(2):256-262
High resolution cytogenetics, microsatellite marker analyses, and fluorescence in situ hybridization were used to define
Xq deletions encompassing the fragile X gene, FMR1, detected in individuals from two unrelated families. In Family 1, a 19-year-old
male had facial features consistent with fragile X syndrome; however, his profound mental and growth retardation, small testes,
and lover limb skeletal defects and contractures demonstrated a more severe phenotype, suggestive of a contiguous gene syndrome.
A cytogenetic deletion including Xq26.3–q27.3 was observed in the proband, his phenotypically normal mother, and his learning-disabled
non-dysmorphic sister. Methylation analyses at the FMR1 and androgen receptor loci indicated that the deleted X was inactive
in > 95% of his mother’s white blood cells and 80–85% of the sister’s leukocytes. The proximal breakpoint for the deletion
was approximately 10 Mb centromeric to FMR1, and the distal breakpoint mapped 1 Mb distal to FMR1. This deletion, encompassing
∼13 Mb of DNA, is the largest deletion including FMR1 reported to date. In the second family, a slightly smaller deletion
was detected. A female with moderate to severe mental retardation, seizures, and hypothyroidism, had a de novo cytogenetic
deletion extending from Xq26.3 to q27.3, which removed ∼12 Mb of DNA around the FMR1 gene. Cytogenetic and molecular data
revealed that ∼50% of her white blood cells contained an active deleted X. These findings indicate that males with deletions
including Xq26.3–q27.3 may exhibit a more severe phenotype than typical fragile X males, and females with similar deletions
may have an abnormal phenotype if the deleted X remains active in a significant proportion of the cells. Thus, important genes
for intellectual and neurological development, in addition to FMR1, may reside in Xq26.3–q27.3. One candidate gene in this
region, SOX3, is thought to be involved in neuronal development and its loss may partly explain the more severe phenotypes
of our patients.
Received: 19 December 1996 / Accepted: 13 March 1997 相似文献
87.
A covalently bound photoisomerizable agonist. Comparison with reversibly bound agonists at electrophorus electroplaques 下载免费PDF全文
HA Lester ME Krouse MM Nass NH Wassermann BF Erlanger 《The Journal of general physiology》1980,75(2):207-232
After disulphide bonds are reduced with dithiothreitol, trans-3- (α-bromomethyl)-3’-[α- (trimethylammonium)methyl]azobenzene (trans-QBr) alkylates a sulfhydryl group on receptors. The membrane conductance induced by this “tethered agonist” shares many properties with that induced by reversible agonists. Equilibrium conductance increases as the membrane potential is made more negative; the voltage sensitivity resembles that seen with 50 [mu]M carbachol. Voltage- jump relaxations follow an exponential time-course; the rate constants are about twice as large as those seen with 50 μM carbachol and have the same voltage and temperature sensitivity. With reversible agonists, the rate of channel opening increases with the frequency of agonist-receptor collisions: with tethered trans-Qbr, this rate depends only on intramolecular events. In comparison to the conductance induced by reversible agonists, the QBr-induced conductance is at least 10-fold less sensitive to competitive blockade by tubocurarine and roughly as sensitive to “open-channel blockade” bu QX-222. Light-flash experiments with tethered QBr resemble those with the reversible photoisomerizable agonist, 3,3’,bis-[α-(trimethylammonium)methyl]azobenzene (Bis-Q): the conductance is increased by cis {arrow} trans photoisomerizations and decreased by trans {arrow} cis photoisomerizations. As with Bis-Q, ligh-flash relaxations have the same rate constant as voltage-jump relaxations. Receptors with tethered trans isomer. By comparing the agonist-induced conductance with the cis/tans ratio, we conclude that each channel’s activation is determined by the configuration of a single tethered QBr molecule. The QBr-induced conductance shows slow decreases (time constant, several hundred milliseconds), which can be partially reversed by flashes. The similarities suggest that the same rate-limiting step governs the opening and closing of channels for both reversible and tethered agonists. Therefore, this step is probably not the initial encounter between agonist and receptor molecules. 相似文献
88.
Cyanobacteria possess thylakoid membranes that differ in their protein composition from the cytoplasmic membrane. To study possible pathways of protein targeting to these membranes, we have investigated whether or not cyanobacteria have a homologue or homologues of the signal recognition particle-like chaperone Ffh. We have amplified a fragment of ffh by polymerase chain reaction and established that ffh is present as a single copy in the genomes of three cyanobacterial species. We have cloned and sequenced ffh from Synechococcus sp. PCC7942 and predict that Ffh functions as a ribonucleoprotein in cyanobacteria and chloroplasts. 相似文献
89.
Worldwide prevalence of lentivirus infection in wild feline species: epidemiologic and phylogenetic aspects. 总被引:11,自引:0,他引:11 下载免费PDF全文
R A Olmsted R Langley M E Roelke R M Goeken D Adger-Johnson J P Goff J P Albert C Packer M K Laurenson T M Caro et al. 《Journal of virology》1992,66(10):6008-6018
The natural occurrence of lentiviruses closely related to feline immunodeficiency virus (FIV) in nondomestic felid species is shown here to be worldwide. Cross-reactive antibodies to FIV were common in several free-ranging populations of large cats, including East African lions and cheetahs of the Serengeti ecosystem and in puma (also called cougar or mountain lion) populations throughout North America. Infectious puma lentivirus (PLV) was isolated from several Florida panthers, a severely endangered relict puma subspecies inhabiting the Big Cypress Swamp and Everglades ecosystems in southern Florida. Phylogenetic analysis of PLV genomic sequences from disparate geographic isolates revealed appreciable divergence from domestic cat FIV sequences as well as between PLV sequences found in different North American locales. The level of sequence divergence between PLV and FIV was greater than the level of divergence between human and certain simian immunodeficiency viruses, suggesting that the transmission of FIV between feline species is infrequent and parallels in time the emergence of HIV from simian ancestors. 相似文献
90.
Larry W. Chang Joseph Kagaayi Gertrude Nakigozi Victor Ssempijja Arnold H. Packer David Serwadda Thomas C. Quinn Ronald H. Gray Robert C. Bollinger Steven J. Reynolds 《PloS one》2010,5(6)