238
M. Maffia et al.
study of ion and metabolite transport through the enterocyte cell
membrane. These data, which are part of a larger scientific project related
to the study of biochemical and physiological adaptation to low Antarctic
temperature, deal with the investigation of molecular adaptation
mechanisms which allow these teleosts to keep the activities of their
carrier proteins compatible with maintenance of basic homeostatic
processes at below zero temperatures.
Material and Methods
Specimens of Trematomus bernacchii were collected in the Ross Sea
(Antarctica) and kept unfed in open circulating seawater aquaria of the
Italian Station in Terra Nova Bay at 0 °C for at least 2 weeks before
sacrifice.
Fish were killed with a sharp blow on the head and intestines were
rapidly used for brush border membrane vesicles (BBMV) prepared by
selective Mg2+-precipitation [3]. These vesicles were employed for indirect
transport measurements through plasma membranes with fluorescent dyes
and for enzymatic determinations [3]. Some intestines were immediately
frozen in liquid nitrogen, stored at -80°C, and used for BBMV
preparations that were subsequently employed in uptake experiments with
radioactive DC 4 C]-glucose in the Laboratory of General Physiology
(Lecce, Italy).
European eels (Anguilla anguilla) at the yellow stage were purchased
from the commercial pond Ittica Ugento (Lecce, Italy) and kept without
feeding in recirculating seawater aquaria at 18°C for at least 2 weeks All
reagents were purchased from Sigma Chemical Co (St. Louis, MO). The
Na + -coupled cotransport activities of isolated BBMV were measured at -1
°C in Terra Nova Bay by using a fluorescent dye sensitive to electrical
membrane potential changes, DiS-C2(5), and in the Laboratory of General
Physiology (Lecce) by using radioactive D-glucose, according techniques
described in detail elsewhere [3]. The enzymatic activity of Na + /K+ATPase of entire mucosal homogenate was measured by following the
appearance of inorganic phosphate [3]. Statistical analysis of data was
performed by ANOVA and Student's t-test (*= p<0.05, * *= p
N a + -Dependent Transport Systems of T. bernacchii Intestinal
BBMV
Figure 1 shows a representative experiment performed at Terra Nova Bay
using the electrical membrane potential sensitive fluorescent dye, DiSC2(5), as previously described [3]. The upper trace represents nonspecific
M. Maffia et al.
study of ion and metabolite transport through the enterocyte cell
membrane. These data, which are part of a larger scientific project related
to the study of biochemical and physiological adaptation to low Antarctic
temperature, deal with the investigation of molecular adaptation
mechanisms which allow these teleosts to keep the activities of their
carrier proteins compatible with maintenance of basic homeostatic
processes at below zero temperatures.
Material and Methods
Specimens of Trematomus bernacchii were collected in the Ross Sea
(Antarctica) and kept unfed in open circulating seawater aquaria of the
Italian Station in Terra Nova Bay at 0 °C for at least 2 weeks before
sacrifice.
Fish were killed with a sharp blow on the head and intestines were
rapidly used for brush border membrane vesicles (BBMV) prepared by
selective Mg2+-precipitation [3]. These vesicles were employed for indirect
transport measurements through plasma membranes with fluorescent dyes
and for enzymatic determinations [3]. Some intestines were immediately
frozen in liquid nitrogen, stored at -80°C, and used for BBMV
preparations that were subsequently employed in uptake experiments with
radioactive DC 4 C]-glucose in the Laboratory of General Physiology
(Lecce, Italy).
European eels (Anguilla anguilla) at the yellow stage were purchased
from the commercial pond Ittica Ugento (Lecce, Italy) and kept without
feeding in recirculating seawater aquaria at 18°C for at least 2 weeks All
reagents were purchased from Sigma Chemical Co (St. Louis, MO). The
Na + -coupled cotransport activities of isolated BBMV were measured at -1
°C in Terra Nova Bay by using a fluorescent dye sensitive to electrical
membrane potential changes, DiS-C2(5), and in the Laboratory of General
Physiology (Lecce) by using radioactive D-glucose, according techniques
described in detail elsewhere [3]. The enzymatic activity of Na + /K+ATPase of entire mucosal homogenate was measured by following the
appearance of inorganic phosphate [3]. Statistical analysis of data was
performed by ANOVA and Student's t-test (*= p<0.05, * *= p
N a + -Dependent Transport Systems of T. bernacchii Intestinal
BBMV
Figure 1 shows a representative experiment performed at Terra Nova Bay
using the electrical membrane potential sensitive fluorescent dye, DiSC2(5), as previously described [3]. The upper trace represents nonspecific