Bariloche protein symposium argentine society for biochemistry and molecular biology

150
BIOCELL, 27 (Suppl. I), 2003
LI-P10.
DOMAIN SEGREGATION IN MYELIN MONOLAYERS
INDUCED BY AQUEOUS PHASE CONDITIONS
Oliveira Rafael and Maggio Bruno.
Departamento de Química Biológica-CIQUIBIC. Facultad de
Ciencias Químicas. Universidad Nacional de Córdoba, Argentina.
E-mail: [e-mail]
Purified myelin spreads as monolayers at the air-water interface.
These were visualized by fluorescence and Brewster angle
microscopy, showing phase coexistence at low surface pressures
(below 20-30 mN/m). Beyond this threshold, the phase coexistence
was present or not depending on the aqueous phase composition.
Pure water, carbohydrate and glycerol solutions (20%) produced
homogeneous monolayers, on the other hand, the presence of salts
in Ringer´s and physiological solution leads to heterogeneity. These
results show (in agreement with previous work) that surface
homogeneity is favored by high water activity or when water
activity is lowered by highly hydroxilated solutes. It has been
previously suggested that domain segregation in nerve myelin
multilayers is coupled to closer apposition among adjacent bilayers
on dehydration and a subsequent extrusion of proteins in laterally
segregated domains. In the monolayer system, where interaction
with any other surface is absent, analogous protein-enriched
domain segregation is induced. In our experiments, monolayer
dehydration can occur by, a) increasing solute concentration in
the subphase b) monolayer compression. Nevertheless, both
methods have coupled another processes and lead to opposite
results.
LI-P11.
THE UNSAPONIFIABLE MATTER OF VIRGIN OLIVE
OIL AFFECTS THE  POSTPRANDIAL TRIGLYCERIDE
CONCENTRATION IN THE PLASMA OF HEALTHY
HUMANS
Perona JS, Sanchez-Domínguez JM, Montero E*, Garcia M* and
Ruiz-Gutierrez V.
Instituto de la Grasa (CSIC). Seville. Spain.*HH.UU. Virgen del
Rocío. Seville. Spain. E-mail: [e-mail]
The present study was carried out in order to evaluate the postprandial
triglyceride changes occurring in the plasma of a group of nine healthy subjects
after the ingestion of meals enriched in olive oil containing different amounts
of its unsaponifiable fraction: refined olive oil (0%, RO), virgin olive oil (2%,
VO) or enriched virgin olive oil (4%, EVO). Fasting (0 h) and postprandial
blood samples were collected hourly for seven hours. Mean plasma triglyceride,
total, LDL- and HDL-cholesterol, apolipoprotein A (apo A) and B (Apo B)
concentrations were measured. Only the triglyceride levels were found to
change after the intake of the oils. A rapid increase over fasting values was
observed, showing a maximum concentration approximately at 2h. The plasma
triglyceride profiles (concentration versus time) were adjusted to polynomical
equations (r
2
=0.996 for the RO curve, r
2
=0.999 for the VO curve and r
2
=0.999
for the VO curve), which allowed the calculation of the precise times at which
peaks of concentration occurred. Thus, we found that the maximum
concentration after RO occurred at 1.4h, at 2.0h after VO and at 1.9h after
EVO. In addition, we found another maximum peak at 6 hours after the intake
of RO and VO. In contrast, the second peak after RO occurred after the 7th
hour, the last time recorded. Consumption of RO showed the smallest peak
(109.5 mg/dL) and consumption of EVO the highest (176.6 mg/dL). Therefore,
we conclude that the amount of unsaponifiable matter in dietary virgin olive
oil affects the postprandial metabolism of triglycerides. Interestingly, we
observed that the higher the amount of unsaponifiable fraction, the higher the
concentration of TG in plasma and chylomicrons and cholesterol in
chylomicrons, suggesting that these lipid components might enhance the
secretion of these lipid classes to the blood stream or reduce their clearance.
Supported by grants from the CICYT (ALI99-0863 and AGL2002-00195
ALI).
LI-P12.
VIRGIN OLIVE OIL TRIGLYCERIDE MOLECULAR
SPECIES AS INDEPENDENT DETERMINANTS OF VLDL
LIPID COMPOSITION IN ELDERLY PEOPLE
Perona JS, Sanchez-Domínguez JM, Montero E
1
, Cañizares J
2
 and
Ruiz-Gutierrez V.
Instituto de la Grasa (CSIC). Seville. Spain.
1
HH.UU. Virgen del
Rocío. Seville. Spain. 
2
Residencia de la Tercera Edad Heliópolis.
Seville. Spain. E-mail: [e-mail]
Two virgin olive oils (VOO1 and VOO2), of the same variety (Olea
europaea var. hojiblanca), with a similar composition in minor
components but differing in the content of triglyceride molecular
species, were tested in order to investigate their effect on the VLDL
lipid composition of elderly people. Twenty-one participants, 84.9
(SD 6.4) year-old, were recruited for the study. After overnight
fasting, blood was collected and VLDL isolated by
ultracentrifugation. The lipid classes, TG molecular species and
TG fatty acid composition were determined. VOO1 presented
higher amounts of triolein (OOO) (p<0.01), whereas VOO2 was
significantly enriched in linoleic-acid species, such as dilinoleoyl-
oleoyl-glycerol (LLO), linoleoyl-dioleoyl-glycerol (LOO) and
linoleoyl-oleoyl-palmitoyl-glycerol (LOP) (p<0.01). Consumption
of VOO1 caused an increase of total TG in VLDL (p<0.01) mainly
due to higher amounts of OOO and LOO. When VOO2 was
administrated an increase in VLDL cholesteryl-esters (p<0.01)
and arachidonic acid-rich TG (p<0.01) was observed. We conclude
that the TG molecular species of dietary oils may be determinant
of the lipid composition of VLDL in elderly people independently
of the fatty acid composition and, therefore, might have a relevant
role in regulating lipoprotein metabolism in these subjects.
Supported by grants from the European Union (FEDER 1FD97-
2288) and INIA (CAO-001-002).
LI-P13.
VACCINE DEVELOPMENT: “MIXED SATURATED AND
UNSATURATED-POLYMER LIPIDS FORMULATIONS,
BIOPHYSICAL AND BIOLOGICAL EVALUATION”
Temprana F, Gasparri J, Taira MC, Lioy V, and  Alonso-
Romanowski S.
Universidad Nacional de Quilmes, Depto de Ciencia y Tecnología,
Laboratorio de Bio-Membranas (LBM). Roque Sáenz Peña 180
Bernal, (1876) Bs As. Argentina. E-mail: [e-mail]
Since liposomes entrapped materials and protect them from
enzymatic attack until they reach a target site, the potential
usefulness of liposomes as carriers and adjuvants for developing
vaccines has attracted considerably interest. Our main objective
is to characterize structurally, morphologically and citotoxicity in
vitro the performance of polymerized diacetylenic liposomes and
its adjuvant capacity in vivo. Formulations contained: 1,2-
bis(10,12-tricosadiynoil)-sn-glycero-3-phosphocholine (DIAPC)
and dimyristoilphosphatidyl choline (DMPC) were UV
polymerized . Determination of the hydrodynamic volume was
obtained by Light Scattering. The hydrophobicity index of vesicles
was determined with MC540 probe at different temperatures.
Citotoxicity was evaluated by hemolysis of red blood cells and
peroxidation index with TBA method. Serum proteins interactions
were tested by SDS-PAGE electrophoresis. The results obtained
showed that there is no significant toxicity of the formulations
proposed with diacetylenic lipids. Polymerisation induces
hydrophobic defects that does not affect the size of the vesicles
and showed preferential interaction with high molecular weight
serum proteins.

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