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C. WALL D. G. GARTHWAITE J. A. BLOOD. SMYTH A. SHERWOOD 《The Annals of applied biology》1987,110(2):223-229
SUMMARY
The efficacy of monitoring the pea moth ( Cydia nigricana ) in dry-harvested pea fields with pheromone traps was evaluated on commercial farms in Eastern England used by ADAS as back-up monitoring sites. In particular the use of a 'threshold' catch to determine both the need for and timing of insecticide sprays was evaluated. Fields in which 'threshold' catches were achieved had more damage in unsprayed plots than fields in which there were no 'threshold' catches. When two sprays were applied to crops at 'threshold' sites, the timing of the first predicted by the monitoring system, excellent control was achieved with 85% of crops having less than 1% peas damaged, and none more than 2–3%. Incorrectly timed sprays, or even one correctly timed spray, produced erratic control.
Simple assessments of economic loss show that it is unnecessary to spray crops in which a 'threshold' is not achieved. Spraying 'threshold' crops, however, is very worthwhile and applying two sprays, the first timed with pheromone traps, will be particularly advantageous to both growers of peas for human consumption when 'clean' crops are at a premium, and to seed producers.
The data can be used to predict the probabilities of damage levels, assuming different control strategies. 相似文献
The efficacy of monitoring the pea moth ( Cydia nigricana ) in dry-harvested pea fields with pheromone traps was evaluated on commercial farms in Eastern England used by ADAS as back-up monitoring sites. In particular the use of a 'threshold' catch to determine both the need for and timing of insecticide sprays was evaluated. Fields in which 'threshold' catches were achieved had more damage in unsprayed plots than fields in which there were no 'threshold' catches. When two sprays were applied to crops at 'threshold' sites, the timing of the first predicted by the monitoring system, excellent control was achieved with 85% of crops having less than 1% peas damaged, and none more than 2–3%. Incorrectly timed sprays, or even one correctly timed spray, produced erratic control.
Simple assessments of economic loss show that it is unnecessary to spray crops in which a 'threshold' is not achieved. Spraying 'threshold' crops, however, is very worthwhile and applying two sprays, the first timed with pheromone traps, will be particularly advantageous to both growers of peas for human consumption when 'clean' crops are at a premium, and to seed producers.
The data can be used to predict the probabilities of damage levels, assuming different control strategies. 相似文献
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Convergent evolution in discomycetes from bark and wood 总被引:1,自引:0,他引:1
MARTHA A. SHERWOOD 《Botanical journal of the Linnean Society. Linnean Society of London》1981,82(1):15-34
Dry weathered wood (lignum and arid bark support a discomycete flora which is taxonomically extremely diverse and contains a high percentage of species with characters not found in Discomycetes of more mesic habitats. A large proportion of filiform-spored, and all muriform-spored non-lichenized Discomycetes occur in this habitat. Most lignicolous Discomycetes have either a pigmented epithecium or a dark margin which covers the hymenium when dry and many have reviving, gelaious ascomata. Their asci often have a simplified structure difficult to interpret. Weathered wood is a niche which has long continuity in geologic time but is relatively unfavorable for fungi because of exposure, aridity and low nutrient levels. Strong selective pressure has consequently been exerted on those fungi able to colonize it, resulting in a high incidence of convergent evolution. 相似文献
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SOME OBSERVATIONS ON THE VIABILITY OF SEWAGE BACTERIA IN RELATION TO SELF-PURIFICATION OF MUSSELS 总被引:1,自引:1,他引:0
H. P. SHERWOOD 《Journal of applied microbiology》1952,15(1):21-28
SUMMARY: Autoclaved sea water and water removed from the shell cavity of mussels supported the growth of coli-aerogenes bacteria. Attempts to reproduce conditions which had favored multiplication of coli-aerogenes bacteria in purified mussels failed.
'Enrichment' of sea water by repeated re-use for storage of successive lots of mussels, in conjunction with sand filtration and aeration under conditions equivalent to 60 weeks of approved purification, did not promote the growth of coli-aerogenes bacteria.
A culture of Salmonella typhi and Salm. paratyphi B survived for a few days only in sea water favourable to the slow multiplication of Bacterium coli type I. 相似文献
'Enrichment' of sea water by repeated re-use for storage of successive lots of mussels, in conjunction with sand filtration and aeration under conditions equivalent to 60 weeks of approved purification, did not promote the growth of coli-aerogenes bacteria.
A culture of Salmonella typhi and Salm. paratyphi B survived for a few days only in sea water favourable to the slow multiplication of Bacterium coli type I. 相似文献
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SYNOPSIS. Gonadotropin-releasing hormone (GnRH), a small peptidein the brain, is essential for reproduction. It is now clearthat GnRH is part of a family of closely related molecules.The primary structure has been identified for 4 GnRH molecules:mammalian, chicken I, chicken II and salmon. During evolutionthe molecule has been conserved in length, terminal amino acidstructure, 7090% of amino acid sequence and the His2Trp3residues,residues, which are important in the release of gonadotropin.Alterations have occurred in positions 5, 7 and 8, regions thoughtto be involved in receptor binding. The receptors for GnRH haveapparently evolved also in that the mammalian and avian receptorsvary considerably in their ability to bind different GnRH molecules.Other GnRH family members have been distinguished indirectlyby chromatographic or immunological means; 3 different GnRH-likemolecules are present, respectively, in lamprey, sturgeon andsalmon (a second form). Several GnRH-like molecules includingthose in chondrichthyes have not yet been distinguished fromthe proposed salmon II molecule. The lamprey GnRH-like moleculemay be a nodal point inthe analysis of the ancestral molecule;hagfish do not contain a detectable GnRH molecule. The elucidationof the GnRH precursor molecule in human placenta showed thepresence of a 53-amino-acid gene-related peptide of unknownfunction, but did not reveal the basis for expression of multipleGnRH forms in many nonmammalian species. GnRH has a varietyof novel functions in addition to release of gonadotropin fromthe pituitary. During evolution certain functions such as thosein the retina and sympathetic ganglia have apparently disappearedin amniotes, but GnRH placental functions have appeared in mammals. 相似文献
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LOUIS M. SHERWOOD STUART HANDWERGER WILLIAM D. McLAURIN MICHAEL LANNER 《Nature: New biology》1971,233(36):59-61
AN earlier report from this laboratory1 described striking homologies in the amino-acid composition of the peptides obtained from trypsin cleavage of human placental lactogen (HPL) and human growth hormone (HGH) and established a firm biochemical basis for the similarities in biological and immunological activity of the two hormones. The intrachain disulphide bonds were placed in similar locations and the carboxyl-terminal amino-acid sequences were shown to be identical except for one out of fourteen residues2. In other studies3,4, the amino-terminal sequence was determined and noted to be homologous for eleven of the first seventeen residues. We now report the complete amino-acid sequence of HPL and a comparison with the revised structure for HGH recently reported4. These two protein hormones are strikingly similar in structure, being identical in 85% of the corresponding positions. Of twenty-eight amino-acid substitutions, twenty-five are favoured changes and all but two of the twenty-five can be explained in terms of a single base change in the triplet codon5. 相似文献