Identification of a host specificity system inShigella

1980 ◽  
Vol 90 (3) ◽  
pp. 1245-1247 ◽  
Author(s):  
M. I. Tediashvili ◽  
T. M. Uporova ◽  
I. I. Nikol'skaya ◽  
S. S. Debov
Keyword(s):  
Host Specificity ◽  
Specificity System

The host specificity system inEscherichia coli SK

1976 ◽  
Vol 13 (2) ◽  
pp. 79-87 ◽  
Author(s):  
I. I. Nikolskaya ◽  
N. G. Lopatina ◽  
N. M. Chaplygina ◽  
S. S. Debov
Keyword(s):  
Host Specificity ◽  
Inescherichia Coli ◽  
Specificity System

Structures and mechanisms of DNA restriction and modification enzymes

1979 ◽  
Vol 12 (3) ◽  
pp. 315-369 ◽  
Author(s):  
Paul Modrich
Keyword(s):  
Host Cell ◽  
Host Specificity ◽  
Bacterial Cell ◽  
Genetic Information ◽  
Molecular Basis ◽  
Cell Types ◽  
Bacteriophage Λ ◽  
Viral Dna ◽  
Dna Restriction ◽  
Specificity System

DNA restriction and modification enzymes are responsible for the hostspecific barriers to interstrain and interspecies transfer of genetic information that have been observed in a variety of bacterial cell types. Although the phenomenon of host specificity was initially observed in the early 1950s (Luria & Human, 1952; Bertani & Weigle, 1953), it was nearly a decade later that Arber and his colleagues accurately predicted the molecular basis of the phenomenon. Their experiments with bacteriophage λ demonstrated that a given host-specificity system imparts a specific modification to the viral DNA, and further, that restriction of DNA lacking the appropriate modification is s consquence of nucleolytic hydrolysis upon entry into the host cell (Arber & Dussoix, 1962; Dussoix & Arber, 1962; Arber, Hattman & Dussoix, 1963).

Alteration of host specificity in Bacillus subtilis.

1968 ◽  
Vol 32 (4_Pt_1) ◽  
pp. 297-301 ◽  
Author(s):  
D D Gwinn ◽  
W D Lawton
Keyword(s):  
Bacillus Subtilis ◽  
Host Specificity

An ecological study of the branchiobdellid commensals (Annelida-Branchiobdellidae) of some mid-western Ontario crayfish

1968 ◽  
Vol 46 (5) ◽  
pp. 835-843 ◽  
Author(s):  
John E. Bishop
Keyword(s):  
Host Specificity ◽  
Dominant Species ◽  
Ecological Study ◽  
Rabbit Serum ◽  
First Year ◽  
Serological Testing ◽  
Severe Winter ◽  
Orconectes Propinquus ◽  
Winter Conditions ◽  
Laurel Creek

Orconectes propinquus and Cambarus robustus from the Speed River, Sunfish Lake, and Laurel Creek, harbor two branchiobdellids, Cambarincola chirocephala and Pterodrilus distichus. Both adult and cocoon populations of the dominant species (C. chirocephala) are proportional to the size of the host throughout the year, except that first-year crayfish are free of cocoons. The reduction in total number of commensals from autumn to spring can be attributed to severe winter conditions. A subrostral site of preference for adult branchiobdellid attachment, and a dominant abdomen I and II site for cocoon deposition are indicated for O. propinquus. On C. robustus, adults are most commonly found on the antennal bases and among the maxillipeds, and cocoons on the last live abdominal sternites. No host specificity is evident although an unidentified Cambarus sp. from Sunfish Lake is free of commensals. Host incompatibility may explain this, but data from Laurel Creek indicate that silting of the microhabitat is responsible for loss of branchiobdellid population. The crayfish–branchiobdellid relationship is commensal, or at most facultatively parasitic, as adult worms can live without a host for extended periods. Serological testing of rabbit serum containing branchiobdellid antibodies against crayfish serum is negative. The dependence of the egg stage on the host for some undetermined factor or factors is discussed. An Asellus sp. fails to pick up the commensals even when exposed under ideal conditions for colonization.

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