Narrow host range

Pennings, S.C., Multiple factors promoting narrow host range in the sea hare, Aplysia califomica, Oecologia, 82, 192, 1990. 

In the past several years a number of investigations on the chemistry of phytotoxins from weed pathogens has uncovered novel structures. The biological activity of these compounds varied from non-selective to narrow host range phytotoxicity (2,... 

Stager (1907) differentiated C. sesleriae from C. purpurea var purpurea based on larger conidia (10.5-14 X 3.5-0.7 pm) and a narrower host range. C. sesleriae is considered synonymous with C. purpurea var purpurea (Bove, 1970 Langdon, 1954 Skalicky and Stary, 1962). 

A. Characteristics. The smallpox virus is an orthopoxvirus with a narrow host range confined to humans. Eradication of the natural disease was completed in 1977. Appearance of human cases would signal use of the virus as a biological weapon. Under natural conditions, the virus is transmitted by direct contact with an infected case, by fomites, and occasionally by aerosols. Smallpox virus is highly stable and retains infectivity for long periods outside of the host. A related virus, monkeypox, clinically resembles smallpox and causes sporadic human disease in West and Central Africa. The incubation period is typically 12 days (range, 10-17 days). 

Figure 3. Strategy for marker exchange. Zig-zag lines denote the vector portion of the suicide plasmid. (i) A narrow-host range (suicide) plasmid, carrying a deletion allele of the ina gene, is transferred from E. coli to Pseudomonas (where it cannot replicate). (ii) Selection for Tc selects cells where the Tc marker has been rescued by a single crossover between plasmid and chromosome. Stage "a" is now complete. (iii) Growth without antibiotic selection permits the appearance of cells in which the plasmid was excised by a second, single crossover, and (iv) was subsequently lost. There are two possible outcomes either the deletion allele substitutes the wild type allele, or the wild type allele is restored. Stage "b" is now complete.

The flea beetle Phyllotreta cruciferae has a narrow host range, feeding only from plants in the families Brassicaceae, Capparidaceae, and Tropaeolaceae. In the laboratory, the insect fed on plants of these families and the Limnanthaceae. All of these plants contain glucosinolates. Field experiments showed that allyl isothiocyanate (26) (Fig. 17.1) is a powerful attractant for adults of both Phyllotreta cruciferae and P. striolata (Feeny et al., 1970). 

The inability of the narrow-host-range E. coli vectors to replicate in other bacterial species. 

Another attribute of the NPVs is their host specificity. Viruses from the family Baculoviridae are found only in arthropods and generally possess narrow host ranges even within an insect order. Host specificity studies utilizing electron microscopy, DNA hybridization, and recombinant DNA technology have demonstrated that the baculovirus lacks the ability to transfer viral DNA into the mammalian cell nucleus even when an established cell line is used for infection (16-18), In addition, extensive studies have shown that baculovirus insecticides are safe for non-target species and the environment (19,20),... 

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