Vol.27-Issue 2- 2003
Vol.27-Issue 2- 2003
Role
of mast cells in gastrointestinal mucosal defense
ALICIA B. PENISSI*, MARÍA I. RUDOLPH**, RAMÓN S.
PIEZZI*
* Instituto de Histología y Embriología “Dr. Mario H. Burgos”
(IHEM-CONICET),
Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Casilla de
Correo 56, (5500) Mendoza, Argentina.
** Departamento de Farmacología, Facultad de Ciencias Biológicas,
Universidad de Concepción, Casilla 160-C, Concepción, Chile.
Key
words: mast
cells, mucosal defense, gastrointestinal, dehydroleucodine
ABSTRACT: The purpose of this review, based on studies from
our laboratory as well as from others, is to summarize salient features of mast
cell immunobiology and to describe their associations with gastrointestinal
mucosal defense. Gastrointestinal mast cells are involved in many pathologic
effects, such as food hypersensitivity.
On the other hand, they also play a protective role in defense against parasitic
and microbial infections. Thus, they have both positive and negative effects,
but presently the mechanisms that control the balance of these various effects
are poorly known. It has been suggested that stabilization of mast cells may
be a key mechanism to protect the gastrointestinal tract from injury. Few molecules
are known to possess both mast cell stabilizing and gastrointestinal cytoprotective
activity. These include zinc compounds, sodium cromoglycate, FPL 52694, ketotifen,
aloe vera, certain flavonoids such as quercetin, some sulfated proteoglycans
such as chondroitin sulfate and dehydroleucodine. Dehydroleucodine, a sesquiterpene
lactone isolated from Artemisia douglasiana Besser, exhibits anti-inflammatory
and gastrointestinal cytoprotective action. The lactone stimulates mucus production,
and inhibits histamine and serotonin release from intestinal mast cells. The
lactone could act as a selective mast cell stabilizer by releasing cytoprotective
factors and inhibiting pro-inflammatory mast cell mediators.
Effect
of sugars on the association between cowpea vicilin
(7S
storage proteins) and fungal cells
T.L. ROSE*, V.M. GOMES*, M. DA CUNHA**, K.V.S. FERNANDES*** AND
J. XAVIER-FILHO***
* Laboratório de Fisiologia e Bioquimica de Microrganismos, Centro de
Biociências e Biotecnologia, Universidade Estadual
do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil.
** Laboratório de Biologia Celular e Tecidual, Centro de Biociências
e Biotecnologia, Universidade Estadual do Norte
Fluminense, Campos dos Goytacazes, RJ, Brasil.
*** Laboratório de Química e Função de Proteínas
e Peptídeos, Centro de Biociências e Biotecnologia, Universidade
Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil
Key words: vicilin, cowpea seeds, Saccharomyces cerevisiae, Fusarium oxysporum
ABSTRACT:
Vicilins (7S storage proteins) found in various legume seeds have been
previously shown to interfere with the germination of spores or conidia of phytopathogenic
fungi and inhibit yeast growth and glucose stimulated acidification of the medium
by yeast cells. In the present work vicilins from cowpea (Vigna unguiculata)
seeds were added to the growth medium of Saccharomyces cerevisiae cells
and Fusarium oxysporum conidia. Helix pomatia lectin, wheat
germ agglutinin and Ulex europaeus lectin were used to
identify differences in the binding of the vicilins to the surface of cells
of S. cerevisiae and F. oxysporum treated with this protein.
After the growth period, the material in suspension (yeast cells) was centrifuged
and the final pellet was also treated with different sugar (glucose, sucrose,
glucosamine, N-acetyl-glucosamine) concentrations and 0.1 M HCl for extraction
of vicilins associated to chitinous structures present in yeast cells. Our results
showed that vicilin sub-units were present in the different sugar extracts of
yeast cells pretreated with the vicilins and these proteins were eluted by 0.5
M solutions of sugars in the following order of efficiency of elution: N-acetyl-glucosamine,
sucrose/glucose and glucosamine.
Fine
structural study of the red seaweed Gymnogongrus torulosus
(Phyllophoraceae, Rhodophyta)
JOSÉ M. ESTEVEZ* AND EDUARDO J. CÁCERES**
* Departamento de Química Orgánica (CIHIDECAR-CONICET), FCEyN-Universidad
de Buenos Aires, Ciudad
Universitaria-Pab. 2, 1428 Buenos Aires, Argentina.
** Departamento de Biología, Bioquímica y Farmacia, Universidad
Nacional del Sur, 8000 Bahía Blanca, Argentina.
Key words: anomalous chloroplasts, cell wall, cystocarpic thalli, fine structure, Gymnogongrus torulosus, pit plugs, Rhodophyta.
ABSTRACT:
The present study analyzed several characters of the red seaweed Gymnogongrus
torulosus, such as cellular structure of the thallus, cuticle, pit plug
and cell wall ultrastructure, and morphology of some organelles like plastids,
Golgi bodies and mitochondria. Also, anomalous chloroplasts with thylakoid disorganization
were found in medullary cells. The significance of this thylakoid disposition
is still unclear. This is one of the first studies focused on the fine structure
of a red alga recorded in Argentina.
Proteoglycans
production by aortic vascular smooth muscle cells
from hypertensive rats
NORMA RISLER, CLAUDIA CASTRO, MONTSERRAT CRUZADO, SUSANA GONZÁLEZ
AND ROBERTO MIATELLO
Cell Culture Laboratory, Departments of Pathology and Morphophysiology,
School of Medicine. National University of Cuyo (UNC), Mendoza, Argentina.
Key words: vascular smooth muscle cells, extracellular matrix proteoglycans, hypertension, spontaneously hypertensive rats
ABSTRACT:
Remodeling of large and small arteries contributes to the development and complications
of hypertension. Artery structural changes in chronic sustained hypertension
include vascular smooth muscle cells (VSMC) proliferation and extracellular
matrix (ECM) modifications. Extracellular constituents such as proteoglycans
(PGs), may modulate vascular stiffness and VSMC growth and differentiation.
We examined the effect of growth factors on secreted and membrane-bound PGs
synthesis by cultured aortic smooth muscle cells (SMC) from 12- to 14- week-old
spontaneously hypertensive rats (SHR) and age-matched Wistar rats. After stimulation
with platelet-derived growth factor (PDGF-BB), 10% fetal calf serum (FCS) or
0.1% FCS as control, PGs synthesis (dpm/ng DNA) was evaluated in the medium
(M-ECM) and in the cell layer (PECM)
by a double-isotopic label method using both [3H]-glucosamine and [35S]-sodium
sulfate which are incorporated into all complex carbohydrates or only into sulfated
dysaccharides, respectively. Data are presented as percent of the control (0.1%
FCS). SHR VSMC displayed a significantly greater synthesis of MECM [3H]-PGs
than Wistar rat cells, with both treatments, but no differences in M-ECM [35S]
uptake were found in any case. In the P-ECM, both PDGF-BB and 10% FCS produced
a greater effect on [3H]-PGs and sulfated PGs synthesis in VSMC from SHR. An
important change seen in SHR cells was a significant decreased sulfation, assesed
by [35S]/[ 3H] ratio, in basal and stimulation conditions. Present results indicate
the existence of changes in PGS synthesis and modulation in VSMC from a conduit-artery
of SHR and support the pathophysiological role proposed for matrix proteoglycans
in the vascular wall changes associated to hypertension and related vascular
diseases as atherosclerosis.
Defense
reactions of Dermatobia hominis (Diptera: Cuterebridae)
larval hemocytes
ANA CAROLINA FARALDO, EDY LELLO
Departamento de Morfologia, Instituto de Biociências, Universidade Estadual
Paulista, Botucatu, São Paulo, BRASIL
Key Words: Dermatobia hominis; hemocytes; phagocytosis; nodule formation; encapsulation
ABSTRACT: The defense reactions against biological (Histoplasma capsulatum and Escherichia coli) and non-biological materials (China ink and nylon thread) were tested in vivo in third instar larvae of Dermatobia hominis. The cellular defense performed by larval hemocytes was observed under electron microscopy. China ink particles were phagocytosed by granular cells 5 h after injection. E. coli cells were internalized by granular cells as early as 5 min after injection and totally cleared 180 min post-injection, when many hemocytes appeared disintegrated and others in process of recovering. H. capsulatum yeasts provoked, 24 h after being injected, the beginning of nodule formation. Nylon thread was encapsulated 24 h after the introduction into the hemocoel. Our results suggest that granular cells were the phagocytic cells and also the responsible for the triggering of nodule and capsule formation. In the presence of yeasts cells and nylon thread, they released their granules that chemotactically attracted the plasmatocytes that on their turn, flattened to surround and isolate the foreign material.
Micropropagation
of Ilex dumosa (Aquifoliaceae) from nodal
segments in a tissue culture system
C. LUNA, P. SANSBERRO*, L. MROGINSKI AND J. TARRAGÓ
Instituto de Botánica del Nordeste (IBONE), Facultad de Ciencias Agrarias
(UNNE), Sargento Cabral 2131, CC: 209. (3400)
Corrientes, Argentina.
Key words: Micropropagation, nodal segment, cytokinins, Ilex dumosa
ABSTRACT: Micropropagation of Ilex dumosa var. dumosa R. (“yerba señorita”) from nodal segments containing one axillary bud was investigated. Shoot regeneration from explants of six-year-old plants was readily achieved in 1/4 strength Murashige and Skoog medium (1/4 MS) plus 30 gr·L-1 sucrose and supplemented with 4.4 mM BA. Further multiplication and elongation of the regenerated shoots were obtained by subculture in a fresh medium of similar composition with 1.5 gr·L-1 sucrose. Rooting induction from shoots were achieved in two steps: 1) 7 days in 1/4 MS (30 gr·L-1 sucrose, 0.25 % Phytagel®) with 7.3 mM IBA and 2) 21 days in the same medium without IBA and 20 mM of cadaverine added. Regenerated plants were successfully transferred to soil. This micropropagation schedule can be implemented in breeding programs of Ilex dumosa.
Apoptogenic
effect of the lipophilic o-naphthoquinone CG 10-248
on rat hepatocytes: light and electron microscopy studies
LIDIA M. LOPEZ*, MARTA DUBIN**, PATRICIA H. CARRIZO**, MARIO H. BURGOS***, AMANDA
PELLEGRINO DE
IRALDI* AND ANDRÉS O. M. STOPPANI**
* Departamento de Biología Celular y Neurociencias, Facultad de Medicina,
Universidad de Buenos Aires, Argentina.
** Centro de Investigaciones Bioenergéticas, Facultad de Medicina (UBA-CONICET),
Argentina.
*** Instituto de Histología y Embriología (IHEM-UNCuyo-CONICET),
Mendoza, Argentina.
Keywords: Apoptosis; o-naphthoquinones; hepatocytes; chromatin alteration; mitochondrial swelling membrane; blebs.
ABSTRACT: CG 10-248 (3,4-dihydro-2,2-dimethyl-9-chloro-2H-naphtho[1,2b]pyran- 5,6-dione; CG-NQ), a b-lapachone analogue, modified the ultrastructure of rat hepatocytes, as demonstrated by light and electron microscopy. After 4 h incubation with 100 mM CG-NQ, the following effects were observed: (a) nuclear chromatin condensation; (b) chromatin fragmentation; (c) displacement of mitochondria, concentrated around the nucleus; (d) disruption or expansion of mitochondrial outer or inner membranes, respectively; (e) displacement and alteration of endoplasmic reticulum (rough and smooth); (f) decrease of microvilli; (g) blebbing of plasma membrane and production of apoptotic bodies formed by folding of plasma membrane fragments around mitochondria or peroxysomes; and (h) production of hydrogen peroxide. Expression of such effects varied according to hepatocyte samples and taken together strongly support an apoptotic action of CG-NQ dependent on “reactive oxygen species”.
Abbreviations:
CG-NQ, CG 10-248 o-naphthoquinone; PARP, poly(ADP- ribose)polymerase; DMFA,
dimethylformamide; HRP, horseradish peroxidase.