Effects of Polyamines on the Ice-nucleating Activity ofErwinia uredovoraKUIN-3

Abstract

The effects ofpolyamines on the ice*nucleating activity of an ice"nucleating bacterium, Erwinia uredovora KUIN-3, were investigated. The activity in the outer membrane derived from this bacterium was increased by the addition of spermidine (lOmM). Also, the activity was stabilized in alkaline pH buffer with the addition of polyamine. Further, the addition of methylglyoxal bis(guanylhydrazone) which inhibited the activity of S-adenosylmethionine decarboxylase, inhibited the ice-nucleating activity of the cells of this bacterium. The amount of polyamine in this bacterium was examined using HPLC. The components of the polyamines were three species, putrescine, cadaverine, and spermidine. The amounts of polyamines in the cells and outer membranes after MGBG treatment decreased. The results suggested that polyamine was the most important component of the ice-nucleating material in this bacterium. Much effort has been put into the study of the ability of

The Control of the Production and Secretion of Extracellular Ice-nucleating Material of Erwinia uredovora KUIN-3.

“…Polyamines were extracted using the previously described HCIO4 method (Kawahara et al ., 1993a). The Tosoh polyamine analysis system with the TSKgel Polyaminepak as the analysis column was also used for the analysis and measurement of the polyamines.…”

“…The Tosoh polyamine analysis system with the TSKgel Polyaminepak as the analysis column was also used for the analysis and measurement of the polyamines. The conjugated polyamine content in the cell and EIM were estimated using a previously described method (Kawahara et al, 1993a) .…”

Anti-Ice Nucleating Activity of Surfactants against Silver Iodide in Water-in-Oil Emulsions

“…Various water-soluble substances that inhibit heterogeneous ice nucleation by inactivating INAs have been reported, including some that are biological in origin, − and others that are synthetic polymers. ,,− These substances are hereafter referred to in this study as anti-ice nucleating agents (anti-INAs). Anti-INA molecules inactivate INAs by masking ice nucleating sites distributed on the INA surfaces .…”

Formation of Ice Nucleation-active Vesicles inErwinia uredovoraat Low Temperature and Transport of InaU Molecules into Shed Vesicles

“…This observation suggests the occurence of another possibility that Ina protein molecules act as ice nuclei after they are extracellularly transported into the bulk water phase. lO • l8 ) Kawahara et al 19 ) have reported that E. uredovora, when cultured at a low temperature such as 16°C, sheds Ina matter in the form of a vesicle into the medium. However, it remains unknown whether or not the vesicle contains InaU protein and how the shed vesicle is imparted with ice nucleation activity.…”

“…To define a relationship between the shedding of the vesicles and the ice nucleation activity, E. uredovora KUIN-3 was grown in TS medium and the vesicles were collected using the previously described method 19) with minor modifications. Briefly, 18 h after the culture at 26°C or 54 h after the culture at 10°C, each medium was centrifuged at 5000 x g for 30 min at 4°C to remove most of t To whom correspondence should be addressed.…”