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1.
Behavioral response ofGraminella nigrifrons (Homoptera: Cicadellidae) to experimentally manipulated vibrational signals 总被引:3,自引:0,他引:3
Mate recognition for the leafhopper Graminella nigrifrons(Forbes) occurs when a male spontaneously emits a multisectional vibrational calling song to which females respond by emitting simple pulses. Significant differences were found among males in the duration, number of chirps, and chirp rate within sections of the song and the total song. Repeatability (proportion of total variation due to differences among males) of call features ranged from very low (0.04 for total chirps in song) to high (0.67 for section 3 chirp rate). However, song modification and playback experiments revealed that the variation in the measured song features was not important in determining whether a female will respond. Rather, female response depended only on the presence of two of the three types of pulses which comprise a chirp. These essential pulses were found within chirps of all call sections that contain chirps. Manipulation of chirp rates from 0.58 to 2.70 times the normal rate did not affect female response, nor did changing the period of silence between the essential pulse types from 0.25 to 1.75 times the normal period. These results suggest that components of the male calling song function in mate recognition but are not used by females to discriminate among conspecific males. 相似文献
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3.
Kimberly M. Broekemeier Randy J. Krebsbach Douglas R. Pfeiffer 《Molecular and cellular biochemistry》1994,139(1):33-40
Commercial ruthenium red is often purified by a single recrystallization as described by Luft, J.H. (1971) Anat Rec 171, 347–368, which yields small amounts of material having an apparent molar extinction coefficient of 67,400 at 533 nm. A simple modification to the procedure dramatically improves the yield, allowing crystallization to be repeated. Three times recrystallized ruthenium red has an apparent extinction coefficient of 85,900, the highest value reported to date. Both crude and highly purified ruthenium red can be shown to inhibit reverse activity of the mitochondrial Ca2+ uniporter (uncoupled mitochondria), provided that care is taken to minimize and account for Ca2+ release through the permeability transition pore. Crude ruthenium red is 7–10 fold more potent than the highly purified material in this regard, on an actual ruthenium red concentration basis. The same relative potency is seen against forward uniport (coupled mitochondria), however, the I50 values are 10 fold lower for both the crude and purified preparations. These data demonstrate unambiguously that the energy state of mitochondria affects the sensitivity of the Ca2+ uniporter to ruthenium red preparations, and that both the forward and reverse reactions are subject to complete inhibition. The data suggest, however, that the active inhibitor may not be ruthenium redper se, but one or more of the other ruthenium complexes which are present in ruthenium red preparations.Abbreviations CCP
carbonyl cyanide p-chlorophenylhydrazone
- CSA
cyclosporin A
- Hepes
4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid 相似文献
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Neisseria gonorrhoeae possesses two nicotinamide adenine dinucleotide-independent lactate dehydrogenases 总被引:3,自引:0,他引:3
Randy S. Fischer Gaines C. Martin Premila Rao Roy A. Jensen 《FEMS microbiology letters》1994,115(1):39-44
Abstract An important metabolic capability of Neisseria gonorrhoeae is the utilization of host-derived lactate. Two isoenzymes of the membrane-associated, pyridine dinucleotide-independent type of lactate dehydrogenase (iLDH) participate in lactate assimilation, but exhibit distinctive properties. Isoenzyme iLDH-I utilized lactate exclusively as substrate, exhibiting a preference for the D-isomer. In contrast, isoenzyme iLDH-II exhibited broad substrate specificity (lactate, phenyllactate, and 4-hydroxyphenyllactate), but was stereospecific for the L-isomers. These results explain the difficulty in isolating mutants unable to utilize lactate. 相似文献
6.
7.
Johnson Kristine; Thornhill Randy; Ligon J. David; Zuk Marlene 《Behavioral ecology》1993,4(3):254-259
We used a breeding design involving 18 sires and 108 dams tostudy the heritabilities of male ornaments in red jungle fowl(Gallus gallus). Ornaments used by females to choose mates showedlow heritabilities, with the exception of comb and wattle measures.The general absence of heritability suggests that a geneticcovariance did not exist at the time of this study between mostmale ornaments and female preferences for those ornaments. Thisresult is contrary to a key prediction of the arbitrary or Fisherianhypothesis of sexual selection. Comb size and color are condition-dependenttraits that reflect short-term changes in health, and comb sizeof males was positively correlated with offspring weight. Ourresults are consistent with the expectation of good-genes hypothesesthat male ornaments reflect the ability of males to withstandenvironmental stresses. 相似文献
8.
Prostaglandin H Synthetase-Mediated Metabolism of Dopamine: Implication for Parkinson's Disease 总被引:2,自引:1,他引:1
† Michael B. Mattammal ‡§Randy Strong †Vijaya M. Lakshmi ¶Hyung D. Chung #Alan H. Stephenson 《Journal of neurochemistry》1995,64(4):1645-1654
Abstract: Differences in prostaglandin H synthetase (PHS) activity in the substantia nigra of age- and post-mortem interval-matched parkinsonian, Alzheimer's, and normal control brain tissue were assessed. Prostaglandin E2 (PGE2 , an index of PHS activity) was higher in substantia nigra of parkinsonian brain tissue than Alzheimer's or control tissue. Incubation of substantia nigra slices with arachidonic acid (AA) increased PGE2 synthesis. Dopamine stimulated PHS synthesis of PGE2 . [3 H]Dopamine was activated by PHS to electrophilic intermediate(s) that covalently bound to DNA, microtubulin protein, bovine serum albumin, and sulfhydryl reagents. When AA was replaced by hydrogen peroxide, PHS/H2 O2 -supported binding proceeded at rates similar to those observed with PHS/AA. Indomethacin and aspirin inhibited AA-mediated cooxidation of dopamine but not H2 O2 -mediated metabolism. PHS-mediated metabolism of dopamine was not affected by monoamine oxidase inhibitors. Substrate requirements and effects of specific inhibitors suggest cooxidation of dopamine is mediated by the hydroperoxidase activity of PHS. 32 P-postlabeling was used to detect dopamine-DNA adducts. PHS/AA activation of dopamine in the presence of DNA resulted in the formation of five dopamine-DNA adducts, i.e., 23, 43, 114, 70, and 270 amol/µg DNA. DNA adduct formation was PHS, AA, and dopamine dependent. PHS catalyzed cooxidation of dopamine in dopaminergic neuronal degeneration is discussed. 相似文献
9.
Growth,graviresponsiveness and abscisic-acid content of Zea mays seedlings treated with Fluridone 总被引:1,自引:0,他引:1
Ten-d-old seedlings of Zea mays L. cv. Tx 5855 treated with 1-methyl-3-phenyl-5-(3-[trifluoromethyl]phenyl)-4-(1H)-pyridinone (Fluridone) were analyzed for abscisic acid (ABA) content using high-performance liquid chromatography with an analysis sensitivity of 2.5 ng ABA g-1 fresh weight (FW). Seedlings were divided into three portions: leaves, detipped roots, and root tips (terminal 1.5 mm). Control plants (water treatment only; no Fluridone) were characterized by the following amounts of ABA: leaves, 0.114±0.024 (standard deviation) g ABA g-1 FW; detipped roots, 0.260±0.039±g ABA g-1 FW; root tips, no ABA detected. We did not detect any ABA in tissues of Fluridone-treated plants. Primary roots of treated and untreated seedlings were strongly graviresponsive, with no significant differences between the curvatures or the growth rates of primary roots of Fluridone-treated and control seedlings. These results indicate that 1) Fluridone completely inhibits ABA synthesis, and 2) ABA is not necessary for positive gravitropism by primary roots of Zea mays.Abbreviations ABA
abscisic acid
- Fluridone
1-methyl-3-phenyl-5-(3-[trifluoromethyl]phenyl)-4-(1H)-pyridinone
- FW
fresh weight
- SD
standard deviation 相似文献
10.
Randy Moore 《Plant cell reports》1984,3(5):172-175
Three phases of cohesion were observable during the development of compatible autografts in Solanum pennellii. Phase I cohesion 1) lasted 4–5 d after grafting, 2) was characterized by an average increase in tensile strength of 4 g breaking weight (BW) mm–2 graft area (GA) d–1, and 3) correlated positively with cellular interdigitation at the graft interface. The fresh weight of the scion increased by approximately 5% d–1 during the first 2 d after grafting. Phase II cohesion occurred 5–15 d after grafting, during which time 1) the tensile strength of the graft union increased by 14 g BW mm–2 GA d–1, 2) vascular differentiation across the graft interface was completed, and 3) the fresh weight of the scion increased by 9% d–1. Phase III cohesion occurred subsequent to 15 d after grafting, during which time 1) the tensile strength of the graft union leveled off at a value similar to that of an ungrafted internode, and 2) the fresh weight of the scion increased by 14% d–1. These results are discussed relative to mechanisms underlying the formation of compatible grafts. 相似文献