Cold Filaments Research Articles

Host mutants resistant to phage lambda killing

Host mutants have been isolated which are resistant to killing by the kil protein of an induced λ prophage. In general, such host mutants are defective in adsorption and production of lambdoid phages, and show altered sensitivities to deoxycholate, colicins, and antibiotics. Most of the mutants are cold sensitive and form filaments at the restrictive temperature. These properties seem to implicate the cell envelope in the kil phenomenon. The cold-sensitive host mutants cannot be cured of their prophage; furthermore, growth of the mutants at different temperatures shows a marked negative correlation with the degree of repressor activity of the temperature-sensitive cI857 repressor. These observations suggest that some phage product, perhaps kil protein, is required for cell survival in these mutants.

Entrainment of shelf water by the gulf stream northeast of Cape Hatteras

Entrainment of relatively cold low-salinity water by the Gulf Stream and subsequent formation of a cold filament adjacent to the northern edge of the Gulf Stream were frequently observed during a series of combined ship and aircraft surveys conducted north-eastward of Cape Hatteras between October, 1968, and May, 1969. Particularly well-defined entrainment was observed during mid-May, 1969 when a band of surface water 10 to 15 km wide and 40 meters thick was observed to reach from the continental shelf to the northern edge of the Gulf Stream. Transport seaward from the outer shelf is of the magnitude 104 m3/sec. Failure to observe entrainment during some of the flights agrees with the discontinuous nature of the cold filament adjacent to the northern edge.