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41.
42.
R. R. Hill Jr. F. L. Kolb H. G. Marshall 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,81(1):79-82
Summary Parameters estimated from a Gardner-Eberhart analysis of the F2 generation of a six-parent diallel in oats (Avena sativa L.) were used to compare methods for predicting the performance of F3 row plots. The prediction methods were: (1) individual F2 plant performance (F2I), (2) parent average plus F2 plot deviations (PF2), (3) parent average plus weighted F2 plot deviations (PF2P), (4) best linear unbiased prediction (BLUP) of parent average plus F2 plot deviations (BPF2), and (5) BLUP plus weighted F2 deviations (BF2). The F2 single-plant traits used for prediction were biological yield to predict F3 biological yield, whole plant and primary tiller grain yield for prediction of F3 grain yield, and whole plant and primary tiller harvest index (HI) to predict F3 HI. Prediction methods were evaluated by correlations between predicted and observed F3 performance. Prediction methods and traits for which correlations were greater than for F2I included: BF2 for biological yield, PF2, PF2P and BF2 for whole plant grain yield, PF2, BPF2, and BF2 for primary tiller grain yield. None had a correlation significantly greater than F2I for either measure of HI, where heritability was large. PF2 is the recommended method for traits with low heritability because of its simplicity and because it had the largest or nearly the largest correlation for each of the yield traits. F2I is the recommended method for traits with larger heritability.Contribution No. 8821 of the U.S. Regional Pasture Research LaboratoryDeceased 相似文献
43.
Comparisons were made with human subjects of repellency of free flying Anopheles gambiae using soaps containing deet and permethrin or permethrin alone. The reduction in biting did not differ statistically significantly between these two forms of repellent soap. Some mosquitoes which touched the permethrin soap layer without biting died within the next day. The soap with deet was compared with the same amount of deet in a commercially available stick or as a liquid. Only in the latter form did the repellent show resistance to being washed off by cold water.Electrically heated vaporizing mats containing bio-allethrin were shown to be more effective than smouldering coils containing natural pyrethrins, in that there was more complete prevention of biting, and more rapid knock-down and kill. Operation of the vaporizing mat caused deposition of insecticide on the room surfaces. 相似文献
44.
The direct electrochemistry of redox proteins has been achieved at a variety of electrodes, including modified gold, pyrolytic graphite and metal oxides. Careful design of electrode surfaces and electrolyte conditions are required for the attainment of rapid and reversible protein-electrode interaction. The electron transfer reactions of more complex systems, such as redox enzymes, are now being examined. The 'well-behaved' electrochemistry of redox proteins can be usefully exploited by coupling the electrode reaction to enzymes for which the redox proteins act as cofactors. In systems where direct electron transfer is very slow, small electron carriers, or mediators, may be employed to enhance the rate of electron exchange with the electrode. The organometallic compound ferrocene and its derivatives have proved particularly effective in this role. A new generation of electrochemical biosensors employs ferrocene derivatives as mediators. 相似文献
45.
Effects of Chromosomal Inversion on Cell Fitness in Escherichia Coli K-12 总被引:14,自引:0,他引:14 下载免费PDF全文
In an effort to learn what factors might mitigate the establishment of Escherichia coli variants bearing major chromosomal rearrangements, we have examined the effects on cell growth of two inversions between rRNA operons. One of these inversions, IN(rrnD-rrnE), had been propagated in a commonly used subline of E. coli K-12 for approximately 30 yr before its discovery, a fact that illustrates the absence of obvious detrimental effects associated with the inversion. We found that culturing under conditions requiring repeated transition from stationary phase to rapid growth led to the replacement of IN(rrnD-rrnE) cells by cells that had undergone either of two types of additional chromosomal inversion: one type fully restored the wild-type order, while the other partially restored it. The partial reinversion was also between rrn operons, but it left a small transposition. The tendency for overgrowth by these revertants persisted through several rounds of periodic selection. In contrast, the other inversion, IN(rrnG-rrnE), was associated with severe, detrimental effects. The effects of IN(rrnG-rrnE) were also alleviated by full or partial reinversion. The probable relationship between the severity of the effects caused by the inversions and the degree of displacement of the replication origin is discussed. Spontaneous inversion events between rrn operons separated by 18% of the chromosome were estimated to occur at a frequency of roughly 10(-5). If extended to natural situations, the growth disadvantage together with the relatively high frequency of reinversion suggest that clones of cells with an inversion between these rrn operons would be readily overgrown by revertants. 相似文献
46.
L M Baddour D L Smalley M M Hill G D Christensen 《Canadian journal of microbiology》1988,34(7):901-905
Proposed virulence factors, including multiple antibiotic resistance and slime-mediated adherence, among coagulase-negative staphylococci colonizing healthy individuals from two different study populations were examined. Resistance to methicillin was more commonly seen than initially anticipated. In addition, adherence characteristics, as quantitated by a microtiter plate method, were very similar to those of strains of coagulase-negative staphylococci causing nosocomial infections. 相似文献
47.
Ronald J. Hill Margaret R. Mott Fujiko Watt Theodora Fifis P. Anne Underwood 《Chromosoma》1986,94(6):441-448
An antigen making a major contribution to the immune response to Drosophila melanogaster chromatin resides primarily on a nonhistone charge-class family of proteins of Mr 74,000. Immunofluorescence detects this antigen at interbands, puffs and diffuse bands of D. melanogaster salivary chromosomes isolated without exposure to acid fixatives, and on nucleoplasmic ribonucleoprotein droplets. In the electron microscope, gold labelling reveals the binding of monoclonal antibodies specific for the antigen at chromosomal loci generally bearing putative ribonucleoprotein (RNP) particles. However, the locus 3C 11–12 is remarkable in that it bears putative RNP particles but is virtually unlabelled, suggesting protein specificity at different active loci. 相似文献
48.
The ligand binding specificity and tissue localization of a rat alveolar macrophage lectin 总被引:2,自引:0,他引:2
The parameters of the reaction between a rat alveolar macrophage lectin (Mr = 180,000) and its ligands have been examined. The reaction is dependent on Ca2+ over the optimal pH range for binding. The apparent dissociation constant for fucosyl bovine serum albumin, the standard ligand used in these studies, is 1.4 X 10(-10) M. The ligand binding specificity was determined by measurement of the inhibition of binding of fucosyl bovine serum albumin by various glycoproteins and saccharides. D-Mannose, L-fucose, and N-acetyl-D-glucosamine were the most effective inhibitors, and D-galactose was much poorer. The equatorial hydroxyl groups on the C-3 and C-4 of the mannose ring are important in the lectin-ligand interaction, and the axial hydroxyl group on the C-2 contributes to a lesser extent. Immunocytological studies revealed that the lectin isolated from alveolar macrophages is widely distributed in other rat tissues. Hepatocytes are devoid of the lectin, but hepatic Kupffer cells and endothelial cells contain significant amounts. This was confirmed by isolation of the lectin from liver. Spleen and skeletal muscle also contain lectin, but much smaller amounts were found in brain, kidney, and heart muscle. 相似文献
49.
The equipment used for the first sampling of arterial blood at depth on free-diving Weddell seals Leptonychotes weddelli is described. Blood was withdrawn through an aortic catheter by a submersible, peristaltic roller pump and stored in a single- or multiple-sample collection device. The multiple sampler allowed up to eight individual blood samples to be collected during a single dive. The blood pump was controlled by a dedicated microcomputer that allowed initiation of blood sampling at flexible combinations of depth and/or time during either the descending or ascending phase of the dive. The dedicated microcomputer also recorded swimming depth, velocity, heart rate, and body temperature at selectable time intervals. These data were transmitted to a laboratory computer, and blood samples were retrieved, when the seal surfaced to breathe. 相似文献
50.
M Ogasawara K Granfors D H Kono J L Hill D T Yu 《Journal of immunology (Baltimore, Md. : 1950)》1985,135(1):553-559
It has been suggested that the O-side chains of the lipopolysaccharide (LPS) of serotype 0:3 strains of Yersinia enterocolitica vary quantitatively and qualitatively depending on whether they are cultured at 37 degrees C or 25 degrees C. It is uncertain whether this affects the expression of the serotype-specific antigens that are probably carried on the LPS. We studied this question with a serotype 0:3-specific monoclonal antibody, 2C1. This monoclonal antibody immunoprecipitated a 39K major protein from detergent-solubilized 125I-labeled Yersinia preparation. However, results of Western blot experiments demonstrated that the antigens reactive with 2C1 were not actually the 39K protein but the O-side chains of the LPS. Significantly, reactivity could be detected whether the bacteria were cultured at room temperature or at 37 degrees C. However, absorption experiments confirmed that there were less accessible antigenic determinants on the 37 degrees C-LPS. The LPS preparations were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining. These SDS-PAGE profiles showed that less O-side chains were present in the 37 degrees C-LPS. Hence, the most likely explanation for our observation is that the 37 degrees C incubation condition induced a partial smooth to rough transition of the Yersinia LPS with a decrease in the amount of 2C1-reactive antigen. 相似文献