Host specificity

Stmcture searching and display software are host-specific. The Softon Substmcture Search System (S4) was developed by the Beilstein Institute and Softon of Graefelfing Germany (50). It is a full stmcture and substmcture searching module. The S4 is used in-house by the Beilstein Institute and is operated by DIALOG. STN uses CAS ONLINE s messenger software for on-line stmcture searching of the Beilstein on-line database (51). 

Baculovimses, especially nuclear polyhedrosis viruses (NPV) and granulosis viruses (GV), appear to be exceptionally well suited for IPM because of their extreme insect specificity. They are stomach poisons and are slow-acting. In vitro production is difficult and the products are more expensive than the bacterial insecticides. Their high host specificity is viewed as a commercial disadvantage, and improvements in formulations and appHcation techniques are needed. 

Unfortunately these and other existing quality control procedures do not answer aU problems. There remains a clear need for development of PCR reference materials that win provide information both on quality and quantity levels. For quality the reference materials should be host-specific and PCR primers, for positive control, may correspond to host specific house keeping genes e.g. b-actin. For quantitative analysis, fluorescence dyes in specific primers might be used in order to measure accurately the amount of DNA present. Such practices, and other as yet un-realized procedures, will be needed to achieve reliable results in the quantification of DNA analysis. 

The pathogenicity of DRB to crop plants has been shown to be host-specific (35) and thus is conceivably linked to root exudation. Alstrom (169) found that the pathogenicity of two isolates of Pseudomonas was determined by the major components of the broth culture in which they were applied to bean seedlings. Both isolates were pathogenic to bean seedlings when the broth contained sucrose and peptone or sucrose and yea.st extract. When the broth contained sucrose alone, one isolate was pathogenic and the other was not. Neither isolate was pathogenic when the broth contained yea.st extract or peptone alone (169). 

P. Lerouge, P. Roche, C. Faucher, F. Maillet, G. Truchet, J. C. Prome, and J. Denarie, Symbiotic host-specificity of Rhizohium meliloti is determined by a sulphated and acylated glucosamine oligosaccharide signal. Nature 344 781 (1990). 

Z. Banfalvi and A. Kondorosi, Production of root hair deformation factors by Rhizohium meliloti nodulation genes in Escherichia coli H.mD (NocM) is involved in the plant host-specific modification of the NodABS-factor. Plant Mol. Biol. 13 1 (1989). 

O. Geiger, E. P. Kennedy, V. N. Reinhold, and B. J. J. Lugtenberg, A novel, highly unsaturated fatty acid moiety of lipooligosaccharide signals determines host specificity of Rhizohium. Nature 354 125 (1991). 

J. A. Downie, A. Economou, A. K. Scheu, A. W. B. John.son, J. L. Firmin, K. E. Wilson, M. T. Cubo, A. Mavridou, C. Marie, A. Davies and B. P. Surin, The Rhizohium legumino.sarum bv. viciae NodO protein compensates for the exported signal made by the host-specific nodulation genes. Nitrogen Fixation Achievements and... 

G. V. Bloembcrg, E. Kamst, M. Hartevcid, K. M. G. M. van der Drift, J. Haverkamp, J, E. Thomas-Oates, B. J. J. Lugtenberg, and H. P. Spaink. A central domain of Rhizobium NodE protein mediates host specificity by determining the hydropho-bicity of fatty acyl moieties of nodulation factors. Mol. Microbiol. I6 123 (1995). 

The fact that rhizobia can be aborted from infection threads shows (40) that a continuous declaration of identity is necessary throughout the travel, consisting in the exposure of specific surface EPS determinants, in the absence of which the transfer is interrupted. Host specificity between rhizobium and legumes is therefore played at two main levels a chitolipooligosaccharide password, acting at a distance, and an exopolysaccharide passport to be exhibited by the bearer in its trip to the awaiting nodule (40). 

H. P. Spaink, O. Geiger. D. M. Sheeley, A. A. N. Van Brussel, W. S. York, V. N. Reinhold, B. J. J. Lugtenberg, and E. P. Kennedy, The biochemical function of the Rhizobium leguminosarum proteins involved in the production of host-specific signal molecules. Advances in Molecular Genetics of Plant-Microbe Interactions. Vol. 1 (H. Hennecke and D. P. S. Verma, eds.), Kluwer Academic Publishers, Dordrecht, The Netherlands, 1991. 

A knowledge of parasite life cycles is crucial in the understanding of the ways infection is acquired and spread, the pathogenesis of disease, and the ways in which disease might be controlled. Some parasites which infect only humans, such as Enterobius vermicularis (pinworm), have a narrow host specificity, whereas others such as Trichinella spiralis infect numerous species. When other animals harbor the same parasite stage as humans, these animal species may serve as reservoir hosts. Humans infected with a parasite stage usually seen in other animal species are referred to as accidental hosts. 

Attachment There is a high specificity in the interaction between virus and host. The most common basis for host specificity involves the attachment process. The virus particle itself has one or more proteins on the outside which interact with specific cell surface components called receptors. The receptors on the cell surface are normal surface components of the host, such as proteins, polysaccharides, or lipoprotein-polysaccharide complexes, to which the virus particle attaches. In the absence of the receptor site, the virus cannot adsorb, and hence cannot infect. If the receptor site is altered, the host may become resistant to virus infection. However, mutants of the virus can also arise which are able to adsorb to resistant hosts. 

Anderson, TJ. and Jaenike, J. (1997) Host specificity, evolutionary relationships and macrogeographic differentiation among Ascaris populations from humans and pigs. Parasitology 115, 325-342. 

Gemmil, AW., Viney, M.E. and Read, A.F. (2000) The evolutionary ecology of host-specificity experimental studies with Strongyloides ratti. Parasitology 120, 429-437. 

Kolattukudy PE, Kim Y, Li D, Liu ZM, Rogers L (2000) Early molecular communication between Colletotrichum gloeosporioides and its host. In Prusky D, Freemann S, Dickman MB (eds) Collelotrichum, Host specificity, pathology and host-pathogen interaction. American Phytopathological Society Press, St. Paul MN, p 78... 

WOLTERS, B., EILERT, U., Accumulation of acridone-epoxides in callus cultures of Ruta graveolens increased by coculture with non host-specific fungi, Z. Naturforsch., 1982, 37c, 575-583. 

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