Vol.26 - Issue 2 - 2002
Key words: TfR, exosome, mitoptosis, reticulocyte maturation.
ABSTRACT: During the differentiation of erythroid cells, a vast program of maturation takes place, leading to decay or elimination of organelles, including the nucleus, itochondria, ribosomes, lysosomes, endoplasmic reticulum and Golgi apparatus. During the last step of red cell maturation, remaining organelles, primarily mitochondria and ribosomes but also vestiges of others are finally cleared from the cell. This cleaning session also affects specific proteins that are partially or entirely removed from the cell surface. The interplay of the various events and their causal relationships are approached here.
Transgenic
wheat plants resistant to herbicide BASTA obtained
by microprojectile bombardment
MARIANA N. MELCHIORRE,
HERNÁN R. LASCANO AND VICTORIO S.TRIPPI
Instituto de Fitopatología y Fisiología Vegetal. (IFFIVE-INTA).
Camino 60 Cuadras Km 5 °. (X5020ICA) Córdoba, Argentina
Key words: BAR, bombardment, GUS, transformation, Triticum aestivum
ABSTRACT: Wheat (Triticum aestivum) transgenic plants of an important commercial cv (Oasis) was obtained with an eff icient and short procedure. First, the optimum conditions for the embriogenic calli generation from inmature embryos with a high regeneration percentage were established. The transformation of calli was performed by high velocity microprojectile bombardment, using the pAHC25 plasmid, which contains the reporter gene b-gluc
Key words: Lipid hydroperoxides, HPLC, ciprofloxacin, mice.s
ABSTRACT: Ciprofloxacin
(CFX) is an effective and relatively safe antimicrobial used in a variety of
human infections. However, adverse drug reactions and positive results in genotoxic
tests are reported. In order to understand the possible pathophysiological mechanisms
of the toxic effects informed for CFX, lipid hydroperoxides (LOOH) -oxidative
mediators of peroxidation- were quantified in liver and kidney of mice, after
15 to 360 minutes of the ciprofloxacin administration at doses of 10 mg/ Kg
or 100 mg/ Kg by ip route. The peroxidation in the lipid fraction was evaluated
by measuring the amount of hydroperoxides through the oxidation of 1- naphthyldiphenylphospine
into its oxide and further quantification by high performance liquid chromatography.
The initial content of lipid hydroperoxides (nmol/g tissue) was 253 + 3 in kidney
and 143 + 12 in liver. CFX induced the maximal variation to 728 + 101 in kidney
(P < 0.05) and 315 + 31 in liver (P < 0.01), after 15 min of 100 mg/ Kg
single dose. The variation in the LOOH levels was significant in kidney with
both doses used and in liver after 100 mg/ Kg until 60 min after the CFX administration,
and then gradually fell to natural levels.
The results demonstrated the effect of CFX on lipid oxidation, an indicator
of oxidative effect. A natural protective capacity against this oxidation, more
efficient in liver than in kidney, was observed.
Keywords: epithelial sheath; tunica propria; lumen cells; electron microscopy.
ABSTRACT: The ultrastructure
of the ovariole sheath along the Diatraea saccharalis ovariole was studied
by scanning and transmission electron microscopy. Each ovariole is surrounded
by an epithelial sheath, a
tunica propria and scattered lumen cells. These three components of the ovariole
sheath show different ultrastructural
features along the ovariole, in the germarium or in the vitellarium; these differences
are more
evident in the epithelial sheath cells. The epithelial sheath is composed by
two layers of cells, the external one
running longitudinally and the internal one running circularly in the ovariole.
These cells, in vitellarium,
present cytoplasmic bundles of myofilaments that are arranged parallel to the
long axis of the cells; these
myofilaments are apparently related to the contraction movements of the follicles
within the ovariole. The
acellular tunica propria, composed of finely filamentous material, is attached
to the adjacent follicle cells by
adhesive dense plates. Between the epithelial sheath and the tunica propria
there is a population of lumen
cells, with morphological features of secretory activity.
Keywords: naphthoquinone, mitochondria, ultrastructure, oxidative phosphorylation, F0F1-ATP synthase.
ABSTRACT: CG 10-248 (3,4-dihydro-2,2 dimethyl-9-chloro-2H-naphtho[1,2b]pyran-5,6-dione), a ßlapachone analogue, modified the ultrastructure of rat liver mitochondria in vitro, in the absence of added oxidizable substrates. The condensed mitochondrial state was replaced by the orthodox or swollen state to a significant degree. The number of modified mitochondria depended on incubation time and quinone concentration, in the 25-100 mM range. Under the same experimental conditions, mitochondrial respiration was uncoupled as indicated by the increase in the rate of succinate oxidation by controlled mitochondria in metabolic state “4” (not in state “3”), and by the activation of latent F0F1-ATP synthase. Taking into account structural similarities, the results reported here may be valid for other o-naphthoquinones, such as -lapachone.
Abreviations: CG-NQ,
CG 10-248 o-naphthoquinone; DMFA, dimethylformamide
Key words: NADPH-diaphorase, nitric oxide, mesencephalon, rat, raphe
ABSTRACT: NADPH-diaphorase
is a useful technique to reveal NO producing neurons at light microscopic level
(LM). A modification of the technique using the tetrazolium salt BSPT as susbtrate,
is useful to study the ultrastructure of NO neurons. The aim of this work was
to perform a detailed analysis of NADPHdiaphorase reactive neurons in rat mesencephalon
both at light and electron microscopic levels. NADPH-diaphorase reactive neurons
were observed in superior colliculus, in central gray matter, in dorsal and
medial raphe and in the pedunculopontine tegmental nucleus using two histochemical
techniques at LM. Electron microscopy showed deposits on membranes of the endoplasmic
reticulum, Golgi apparatus and nuclear envelope of dorsal raphe neurons. Presynaptic
and postsynaptic terminals showed deposits on membranous elements but postsynaptic
terminals also showed deposits on the inner surface of their membranes. Further
physiological studies are needed to clarify the meaning of the ultrastructural
findings such as the putative interaction of NOS with postsynaptic proteins,
receptors or membranous channels.
Key words: human liver, ultrastructure, cytochemistry
ABSTRACT: The aim
of this paper is to establish whether there are cytochemical or ultrastructural
alterations in the hepatocytes of patients with primary biliary cirrhosis (PBC)
at stages I and II compared with the biopsies from individuals with normal liver.
Cytochemical technique with ATP as substrate, transmission electron microscopy
(TEM) and freeze fracture were used for the studies. In the normal liver biopsies
the ultrastructural cytochemical localization of the enzymatic activity was
clearly shown in the bile canaliculi. In the PBC biopsies, the enzymatic activity
is increased in the bile canaliculi and is also present in the lateral membranes
of the hepatocyte. TEM of the lateral surface of the hepatocyte in normal livers
showed a smooth surface without microvilli but in PBC livers a large number
of microvilli were seen in the lateral embranes. The Golgi apparatus in these
patients was localized not only near the canaliculi (normal livers) but also
in front of the microvilli. Freeze-fracture showed normal features in the bile
canaliculus junctions of the PBC patients. We suggest that the localization
of the enzymatic reaction, microvilli and Golgi apparatus at the PBC hepatocyte
lateral membranes may represent a compensatory mechanism for derivation of bile
flow and other components from the hepatocyte to the intercellular space.
Improved
in vitro embryo development of stenospermic grape by
putrescine
MARÍA TERESA
PONCE, MÓNICA ELIZABETH GUIÑAZÚ AND RICARDO TIZIO
Departamento de Biología. Cátedra de Fisiología Vegetal.
Facultad de Ciencias Agrarias. Universidad Nacional de Cuyo.
Mendoza, Argentina.
* Prof. Eng. Ricardo M. Tizio died on April 16th, 2002.
Key words: putrescine, stenospermic grapes, embryo rescue, plant regeneration, in vitro culture, Vitis vinifera
ABSTRACT: The goal of this study was to determine the effect of putrescine, added to the culture medium, on the in vitro development of stenospermic grape (Vitis vinifera L) embryos. The cross breedings of Perlón x G.C88552 and Perlón x Argentina were used. 0 (control), 2 and 4 mM of putrescine were added to the immature seed’s culture medium. In Perlón x Argentina, 2mM of putrescine statistically increased the percentage of total embryos, direct germination, polyembryos and normal plants. In Perlón x G.C88552, only 2 mM of putrescine increased all the variables considered, eventually tripling the percentage of normal plants obtained. The results suggest that the endogenous concentration of putrescine may be a growth limiting factor. Adding putrescine to the culture medium of immature grape seeds is a legitimate resource to significantly increase the results of this technique.
Abbreviations: put-putrescine,
G.C.-Gargiulo’s Crossing