Genetic resistance

In additional tests, the suppressor activities of pectins in the intact host/pathogen-interaction were investigated by injecting genetically resistant plants with pectic substances prior to inoculation with the rust fungus. Infected leaves were harvested, cleared, and stained with Calcofluor one week after inoculation, and fungal growth was assessed under the UV-epifluorescence microscope. 

Morris, C.A. (2006), Areview of genetic resistance to disease in Bos taurus cattle . Vet J., November (Epub ahead of print). 

Gauly, M. and Erhardt, G. (2001). Genetic resistance to gastrointestinal nematode parasites in Rhon sheep following natural infection . Veterinary Parasitology, 102, 253-259. 

Schou, T., Permin, A., Roepstorff, A., Sorensen, P. and Kjaer, J. (2003). Comparative genetic resistance to Ascaridia galli infections of 4 different commercial layer-lines . British Poultry Science, 44(2), 182-185. 

Plant sensitivity to ozone, PAN, and other oxidants is conditioned by many factors. Genetic diversity between species and between cultivars within a species is well documented. The mechanism of genetic resistance is known for only one onion cultivar and is related to the effect of ozone on stomatal closure. Variants within a natural species are well known for several pine species, including white, loblolly, and ponderosa. 

Dimock, E. J., Silen, R. E., and Allen, V. E. (1976). Genetic resistance on Douglas-fir to damage by snowshoe hare and black-tailed deer. Forest Science 22,106-121. 

There is a continuing debate as to whether inbred or outbred strains of rodents should be used. In theory, inbred strains are preferable because a more accurate knowledge of back-grormd tumour incidence is available. It may be, however, that a particular inbred strain may metabolise the test material in a certain way or have a genetic resistance to the development of a specific tumour type. Usually outbred strains of rat or hamster are used, but occasionally inbred mice strains are included. An FI hybrid mouse strain is frequently employed. In some circumstances outbred Syrian hamsters may be the species of choice. The most important factor is to have a sound knowledge of the background incidence of tumours in the species or strain selected. This information complements the concurrent control data and provides information on the susceptibility of the strain to rare tumour t)rpes. Modif)dng factors, such as diet, cage density, etc., must be kept as constant as possible to enable correct interpretation of the results. ... 

It is also to be taken into account that pests, in response to genetically modified crops that bear genetic resistance, may rapidly become adapted, so that new genetically modified crops are needed to maintain high productivity. A gene associated with Bt resistance has been identified in the cotton pest, Heliothis virescens (Gahan 2001). The life span of a genetically modified crop is calculated to be a few years only (Plucknett 1986). 

Hipskind, J., Wood, K., and Nicholson, R.L., Localized stimulation of anthocyanin accumulation and delineation of pathogen ingress in maize genetically resistant to Bipolaris maydis race O, Physiol Mol Plant Pathol, 49, 247, 1996. 

Three principal types of genetic resistance have been proposed preference or non-preference, antibiosis, and tolerance ( ). 

As with other antibiotics/-1 streptomycin is subject to inactivation by enzymes encoded by genetic resistance factors (Chapter 26). Among these are enzymes that transfer phospho groups... 

HIV-1 genetic resistance to protease inhibitors occurs via specific mutations. Genotypic analysis of the HIV protease gene from isolates selected in vitro indicated that Gly48Val and Leu90Met mutants had reduced susceptibility to saquinavir (Ohta, 1997). Indinavir and ritonavir resistance maps to residue 82, whereas for amprenavir the key mutation is at residue 50 (I50V) and confers a threefold decline in viral sensitivity to amprenavir. Two additional mutations at residues 46 and 47 follow development of mutation at position 50, resulting in a 20-fold de-... 

Gressel, J. and L.A. Segel (1978). The paucity of plants evolving genetic resistance to herbicides Possible reasons and implications. J. Theor. Biol., 75 349. 

Agronomic and other cultivated species would not be acutely impaired if future oxidant and sulfur dioxide levels remain as they are today. There appears to be sufficient genetic resistance to foliar injury within cultivated species that cultivars which are resistant to existing... 

Genetic. The differences between many susceptible and resistant cultivars are the abilities of the latter to appropriately respond quantitatively in time and in space to infection, rather than qualitative differences in biochemical pathways. This type of genetic resistance may be considered a form of an endogenous constitutively sensitized state. Genetic sensitization of a cultivar requires both a source of appropriate germplasm and a method of effective transfer and incorporation of the genetic material into the recipient cultivar. Both requirements cannot always be met. Furthermore, undesirable traits often accompany desired resistance traits. This very important area of plant sensitization, broadly construed, lies beyond the scope of this paper. 

Genetically resistant plants Invariably produce higher levels of phytoalexins than do susceptible genotypes (24,25). 

In some instances, plants can avoid disease in time and space (2) reducing the need for genetic resistance. The success of Colletotrichum gloeosporioides (Penzig.) Sacc. f. sp. aeschvnomene as the bioherbicide Collego for control of northern Jointvetch (Aeschvnomene virginica (L.) B.S.P.) can be attributed to the uniform susceptibility of the weed host (12)- In nature, the pathogen is poorly disseminated such that disease incidence is low... 

I cannot agree with this proposal. There are a number of links between the source or cause and the effect, a whole range of stages as emission, transportation, immission, deposition and dose, and they are influenced by climate, site, genetic resistance, which can alter the picture. In summary, the effect is very far apart from the source. If you measure the dose within the plant, the amount of pollutants which the plant has taken up, or the state of the soil as it has changed by air pollution, then you have a much closer relation to the effect than just by an emission survey. We have now the forest decay just in those areas which are maybe 100 kilometers away from the industrial areas and not in the industrial areas themselves. So this proposal would not work. It is, however, very useful to find out the main sources and to start measures to reduce emissions in general or for certain pollutants. 

A-acetylglucosamine, providing the necessary carboxylate anchor for attachment of the pentapeptide required for bacterial peptidoglycan (cell wall) formation. Bacteria that encode a MurA orthologue where the susceptible Cys is replaced by an Asp (e.g., Mycobacteria) are intrinsically genetically resistant to fosfomycin (Fig. 1) (11, 12). 

That gold salts possess immunosuppressive effects has been demonstrated by both in vivo and in vitro studies [56-59]. In addition, they also have an immu-noenhancing effect on the immune response of mice, depending on dosage [60]. BALB/c mice are highly susceptible to autoimmune interstitial nephritis, while C57BL/6 mice are genetically resistant to this nephritis... 

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