Vol.27-Issue 1-2003
Vol.27-Issue 1-2003
Interaction
of bifidobacteria with the gut and their influence in
the immune function
GABRIELA PERDIGÓN1,2,
MÓNICA LOCASCIO1, MARTA MEDICI1, AIDA PESCE DE RUIZ HOLGADO1,2 AND
GUILLERMO OLIVER1
1. CERELA. Chacabuco
145, 4000 Tucumán, Argentina.
2. Instituto de Microbiología, Facultad de Bioquímica, Química
y Farmacia. Universidad Nacional de Tucumán, Argentina.
Key words: Bifidobacteria, Homologous and Heterologous strains, Immune System.
ABSTRACT: Bifidobacteria
are predominant in the lumen of the large intestine and confer various health
benefits on the host. They are also used in the preparation of new fermented
milks (bioyogurts) or added to conventional yogurt to generate probiotic effects.
The colonization of the gut by bacteria tends to be host specific due partly
to the way in which bacteria adhere to the intestinal wall. Using a homologous
strain of Bifidobacterium animalis in an experimental mouse model, we analyzed
by immunofluorescence labelledbacteria and transmission electronic microscopy
the importance of this bacterial interaction with epithelial an immune cells
associated to the gut, and the effect of feeding of B. animalis in the immune
response. It was able to adhere and interact with both small and large intestine.
In spite of this interaction with the gut, no modifications in the immune state
(secretory or systemic response) were observed. A heterologous strain of Bifidobacterium
adolescentis from human faeces, was neither uncapable of binding to the intestine,
nor influence the immune system activation, when it was administered during
2, 5 or 7 consecutive days; we believe that using a homologous strain, oral
tolerance is developed even when the microorganism interacts with the immune
cells associated with the intestine. However, we cannot ignore the beneficial
effect of these microorganisms, especially in the prevention of intestinal infections.
We think that this property exerted by bifidobacteria is more related to other
mechanisms such as competitive inhibition, acid production or others, than enhancement
of the immune state.
Distribution
of pectins in the pollen apertures of Oenothera
hookeri.velans ster/+ster:
I. NOHER DE HALAC1
, 2, I.A. CISMONDI2 , M.I. RODRIGUEZ-GARCIA3 , G. FAMÁ
1. Centro de Estudio
de las Metabolapatías Congénitas (CEMECO), Cátedra de Clínica
Pediátrica, Facultad de Ciencias
Médicas, Universidad Nacional de Córdoba. 5000 Córdoba,
Argentina. Member of the research career of the Argentinean
Science Council (CONICET).
2. Cátedra de Biología Celular, Facultad de Odontología,
Universidad Nacional de Córdoba. 5000 Córdoba, Argentina.
3. Estación Experimental del Zaidín, CSIC, Profesor Albareda 1,
Granada, Spain.
Key words: pectins, monoclonal antibodies, JIM5, JIM7, immunogold, pollen, sporoderm, Oenothera, cytochemistry
ABSTRACT: Cell wall pectins are some of the most complex biopolymers known, and yet their functions remain largely mysterious. The aim of this paper was to deepen the study of the spatial pattern of pectin distribution in the aperture of Oenothera hookeri.velans ster/+ster fertile pollen. We used “in situ” immunocytochemical techniques at electron microscopy, involving monoclonal antibodies JIM5 and JIM7 directed against pectin epitopes in fertile pollen grains of Oenothera hookeri.velans ster/+ster. The same region was also analyzed by classical cytochemistry for polysaccharide detection. Immunogold labelling at the JIM7 epitope showed only in mature pollen labelling mainly located at the intine endo-aperture region. Cytoplasmic structures near the plasma membrane of the vegetative cell showed no labelling gold grains. In the same pollen stage the labelling at the JIM5 epitope was mostly confined to a layer located in the limit between the endexine and the ektexine at the level of the border of the oncus. Some tubuli at the base of the ektexine showed also an accumulation of gold particles. No JIM5 label was demonstrated in the aperture chamber and either in any cytoplasmic structure of the pollen grains. The immunocytochemical technique, when compared with the traditional methods for non- cellulose polysaccharide cytochemistry is fare more sensitive and allows the univocal determination of temporal and spatial location of pectins recognized by the JIM7 and JIM5 MAbs.
Structure
of the kidney of Bufo arenarum: Intermediate segment,
distal tubule and collecting tubule
ALEJANDRO
FARÍAS, GLADYS NOEMÍ HERMIDA, AND LUISA ELEONORA FIORITO
Naturales, Universidad
de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina.
Key words: Amphibia, kidney, ultrastructure, renal tubules.
ABSTRACT:
The ultrastructure of the intermediate segment (IS), distal tubule
and collecting tubule (CT) of the south american toad Bufo arenarum, was studied
by light and transmission electron microscopy. The IS is composed of cubical
ciliated cells which propel the urine along the renal tubule. The distal tubule
is divided into two portions: the early distal tubule (EDT) and the late distal
tubule (LDT). The EDT is characterized by only one type of cells with well developed
basolateral interdigitations and numerous elongated mitochondria, which are
oriented normal to the basal surface. The “macula densa - like” is
a specialized zone of the EDT in contact with the vascular pole, where cells
are more tightly packed than in the rest of the tubule. The LDT shows two types
of cells called dark and light cells according to the appearance of their cytoplasm.
Dark cells have microplicae and few but long microvilli at their luminal surface,
and abundant mitochondria in their cytoplasm. Light cells show basal and lateral
infoldings and few mitochondria. The CT, which is composed of dark and light
cells, exhibits an enlarged lumen with an undulated surface and dilated spaces
between
neighbouring cells. This work is a contribution to the knowledge of the kidney
of B. arenarum; frequently used as an experimental model for physiological and
biochemical studies.
Incidence
of sperm-tail tyrosine phosphorylation and
hyperactivated motility in normozoospermic and
asthenozoospermic human sperm samples
ROBERTO YUNES,
GUSTAVO F. DONCEL, AND ANIBAL A. ACOSTA
The Jones Institute for Reproductive Medicine. Department of Obstetrics and
Gynecology. Eastern Virginia Medical School.
Norfolk, VA, USA
Keywords: sperm motility, hyperactivation, asthenozoospermia, tyrosine-phosphorylation, protein-tyrosine kinase.
ABSTRACT: Our objective
was to study the incidence of sperm-tail phosphotyrosine immunoreactivity in
normozoospermic and asthenozoospermic human sperm samples, its association with
sperm motion parameters, particularly hyperactivated motility, and its potential
involvement in the pathogenesis of asthenozoospermia. The work was conducted
as a prospective experimental study in the Sperm Biology and Andrology laboratories
of the Jones Institute, a medical school-based fertility center. The study subjects
were healthy fertile male donors (normozoospermic samples) and infertile patients
(asthenozoospermic samples) attending the center. Recently ejaculated semen
samples were washed twice to eliminate seminal plasma and a swim-up was performed
to select the motile population which, in turn, was incubated up to 18 h at
37oC in
3.5% human serum albumin-supplemented Ham's F10 to allow for capacitation. For
evaluation, sperm aliquots were taken pre-swim-up (To), immediately post swim-up
(T1), at 6 h (T6), and 18 h (T18) of incubation. The main outcome measures were
computer-analyzed sperm motion parameters and hyperactivated motility, and
immunodetection of phosphotyrosine (PY)-containing proteins. During the capacitating
incubation, normozoospermic samples displayed maximum motility, velocity, and
hyperactivation at T6, signif icantly decreasing their values at T18. PY-proteins
were located both at the tail and head of spermatozoa. Their expression increased
progressively during the incubation, being present in about 70% of the sperm
tails at T18. Asthenozoospermic samples showed an inability to respond to capacitation
with an increase in motion parameters and PY-phosphorylation. At T6, both hyperactivation
and PY-phosphorylation were significantly lower than in normal samples. Our
results suggest that PY-phosphorylation of tail proteins is highly conspicuous
in human spermatozoa, and increases its incidence in a time-dependent manner,
as more sperm
become capacitated. Asthenozoospermic samples displaying low percentages of
motile sperm and altered motion characteristics showed a decreased incidence
of PY-phosphorelated sperm. Tail protein PY-phosphorylation may be related to
sperm movement, especially to hyperactivated motility and its deficiency may
be associated to asthenozoospermia.
Antibacterial
activity of lactose-binding lectins from Bufo
arenarum skin
ALICIA SÁNCHEZ
RIERA, ADRIANA DAUD, ADRIANA GALLO, SUSANA GENTA, MANUEL AYBAR, AND SARA SÁNCHEZ
Departamento de Biología
del Desarrollo, Instituto Superior de Investigaciones Biológicas (INSIBIO)
y Universidad Nacional
de Tucumán (UNT). Chacabuco 461, (4000) San Miguel de Tucumán,
Tucumán, Argentina.
Key words: skin, lectin, amphibian, antibacterial activity
ABSTRACT: Amphibians respond to microbial infection through cellular
and humoral defense mechanisms such as antimicrobial protein secretion. Most
humoral defense proteins are synthetized in the skin. In this study we isolated
two b-galactoside-binding lectins with molecular weights of 50 and 56 KDa from
the skin of Bufo arenarum. These lectins have significant hemagglutination activity
against trypsinized rabbit erythrocytes, which was inhibited by galactose-containing
saccharides. They are water-soluble and independent of the presence of calcium.
The antimicrobial analysis for each lectin was performed. At mmolar concentration
lectins show strong bacteriostatic activity against Gram negative bacteria (Escherichia
coli K12 4100 and wild strains of Escherichia coli and Proteus morganii) and
Gram positive bacteria (Enterococcus faecalis). The antibacterial activity of
these lectins may provide an effective defense against invading microbes in
the amphibian Bufo arenarum.
Inhibition
of focal adhesion kinase by antisense oligonucleotides
enhances the sensitivity of breast cancer cells to camptothecins
TAROH
H. SATOH2, TATIANA A. SURMACZ3, OKOT NYORMOI4, AND CECILIA M. WHITACRE1
1. School
of Natural and Health Sciences, Barry University, 11300 N.E. Second Ave., Miami
Shores, FL 33161, USA.
2. Biochemistry and Molecular Genetics, University of Colorado Health Sciences
Center, 4200 E. Ninth Ave., Denver, CO
80262, USA.
3. Max-Planck Research Unit Enzymology of Protein Folding, Weinbergweg 22, D-06120
Halle (Saale), Germany.
4. Department of Cancer Biology, University of Texas, M.D. Anderson Cancer Center,
1515 Holcombe Blvd, Houston, TX
77030, USA.
Key words: focal adhesion kinase; drug resistance; camptothecins; breast
cancer
ABSTRACT: This study shows a strong association between cell attachment
to substratum and activation of b1-integrin-signaling with resistance to the
camptothecin derivative topotecan (TPT) in breast cancer cells. We propose a
mechanistic-driven approach to sensitize the cells to camptothecins. ZR-75-1
anchoragedependent breast cancer cell line, its derivative 9D3S suspension cells
(9D3S-S), and 9D3S cells attached to fibronectin-coated plates (9D3S-A) were
treated with TPT (1 mM) or CPT-11 (40 mM) for 48 h. Programmed cell death (PCD),
as shown by poly(ADP-ribose) polymerase (PARP), pro-caspase-3 and pro-caspase-9
cleavage, was observed in 9D3S-S cells but not in ZR-75-1 or 9D3S-A cells. Because
p125 focal adhesion kinase (FAK) is a transducer in the b1-integrin signaling
pathway, it is essential to cell adhesion and it is overexpressed in metastatic
breast cancer, we hypothesized that attenuation of FAK might enhance the sensitivity
of breast cancer cells to camptothecins. Moreover, inhibition of FAK gene expression
by a phosphorothioated antisense oligodeoxynucleotide targeting the portion
of the gene encoding amino acids 262-268, increased the sensitivity of ZR-75-1,
MDA-MB-231 and MCF7 breast cancer cells to treatment with TPT or CPT-11.
Micropropagation
of Glandularia perakii Cov. et Schn.
(Verbenaceae), a native species with ornamental potential
CONCEPCIÓN
MARINO1, MARÍA T. PONCE1*, MARÍA E. VIDELA2, SONIA FIORETTI3 AND
MIGUEL CIRRINCIONE1.
1. Fisiología
Vegetal. Dpto Ciencias Biológicas. Facultad de Ciencias Agrarias. Universidad
Nacional de Cuyo.
2. Botánica Agrícola. Dpto Ciencias Biológicas. Facultad
de Ciencias Agrarias. Universidad Nacional de Cuyo.
3. Espacios Verdes. Dpto Producción Agropecuaria. Facultad de Ciencias
Agrarias. Universidad Nacional de Cuyo.
Keywords: tissue culture,
in vitro propagation, nodal segment, Glandularia perakii
ABSTRACT: Glandularia perakii is a perennial species with beautiful violet
flowers that grows in the stony soil of Mendocine pedemont. A plentiful and
prolonged flowering confers it an important ornamental potential. In this paper,
a method of propagation of G. perakii from nodal segments is reported. Proliferating
microshoot cultures were obtained by placing nodal segment on Murashige and
Skoog medium (MS) supplemented with 20 g.L-1 of sucrose without growth regulators.
In this medium multiplication rate after 20 days was 7.9. Rooted plants were
acclimatized successfully.
Abbreviations: MS Murashige and Skoog medium; BA – 6-benzyladenine;
IBA – indole-3-butyric acid.