Placental protein 14 induces apoptosis in T cells but not in monocytes. (49/413)

Substantial evidence exists in literature to suggest that placental protein 14 (PP14) (recently renamed glycodelin A), exhibits immunosuppressive properties and is an indispensable macromolecule in the maternal system for the establishment, maintenance, and progression of pregnancy. Though there are several reports substantiating the above, the mechanism of its action at the molecular level has not been elucidated as yet. In this paper we provide data that suggest that amniotic fluid PP14 and recombinant PP14 expressed in Pichia pastoris induce apoptosis in human peripheral blood lymphocytes upon activation, independent of monocytes. That PP14 has a direct apoptotic action on T cells but not on monocytes was also demonstrated by utilizing human cell lines. PP14 was shown to induce apoptosis in the human T cell lines, Jurkat and MOLT-4 cells, but not in the human monocytic cell line, U937.  (+info)

Neutrophil migration in tonsils. (50/413)

Recent studies have indicated the existence of an active cellular defence in the secretion on the tonsillar surface. This defence seems to consist partly of physiologically active neutrophils and is present in health and during disease. The present study was undertaken to examine the migration of these neutrophils to the secretion on the mucosal surface. Tonsils from 6 patients with acute tonsillitis and 5 patients with snoring problems were removed and sectioned. Sections were stained immunohistochemically against CD15 to visualise neutrophils. Other sections were stained with acridine orange to detect bacteria. Clusters of neutrophils were frequently seen in tonsils both from patients with acute tonsillitis and from snorers. They were observed to be accumulated within the tonsillar epithelial layer. Streaks of neutrophils could be observed running not only from vessels mainly near or within the epithelium to the epithelial surface, but also from vessels far from the epithelium through the extrafollicular areas to the epithelial surface. Bacteria were not present in the epithelium. We consider that the findings indicate an active physiological migration of neutrophils to the tonsillar surface.  (+info)

Lack of mitochondrial anionic phospholipids causes an inhibition of translation of protein components of the electron transport chain. A yeast genetic model system for the study of anionic phospholipid function in mitochondria. (51/413)

Reduction of mitochondrial cardiolipin (CL) levels has been postulated to compromise directly the function of several essential enzymes and processes of the mitochondria. There is limited genetic evidence for the critical roles with which CL and its precursor phosphatidylglycerol (PG) have been associated. A null allele of the PGS1 gene from Saccharomyces cerevisiae, which encodes the enzyme responsible for the synthesis of the CL precursor PG phosphate, was created in a yeast strain in which PGS1 expression is exogenously regulated by doxycycline. The addition of increasing concentrations of doxycycline to the growth medium causes a proportional decrease to undetectable levels of PGS1 transcript, PG phosphate synthase activity, and PG plus CL. The doubling time of this strain with increasing doxycycline increases to senescence in non-fermentable carbon sources or at high temperatures, conditions that do not support growth of the pgs1Delta strain. Doxycycline addition also causes mitochondrial abnormalities as observed by fluorescence microscopy. Products of four mitochondrial encoded genes (COX1, COX2, COX3, and COB) and one nuclear encoded gene (COX4) associated with the mitochondrial inner membrane are not present when PGS1 expression is fully repressed. No translation of these proteins can be detected in cells lacking the PGS1 gene product, although transcription and splicing appear unaffected. Protein import of other nuclear encoded proteins remains unaffected. The remaining proteins encoded by mitochondrial DNA are expressed and translated normally. Thus, the molecular basis for the lack of mitochondrial function in pgs1Delta cells is the failure to translate gene products essential to the electron transport chain.  (+info)

Distinct patterns of insulin-like growth factor binding protein (IGFBP)-2 and IGFBP-3 expression in oxidant exposed lung epithelial cells. (52/413)

Oxygen (O(2)) species are involved in a large variety of pulmonary diseases. Among the various cell types that compose the lung, the epithelial cells of the alveolar structure appear to be a major target for oxidant injury. Despite their importance in the repair processes, the mechanisms which regulate the replication of the stem cells of the alveolar epithelium, the type 2 cells, remain poorly understood. Based on the results of several studies which have documented the involvement of the insulin-like growth factor (IGF) system in lung epithelial cell replication, and which have also suggested a role for IGF binding proteins (IGFBPs) in the control of cell proliferation, the aim of the present work was to determine whether IGFBPs could be involved in the modulation of growth of human lung epithelial cells exposed to oxidants. Experiments were performed using a human lung adenocarcinoma cell line (A549) which was exposed for various durations to hyperoxia (95% O(2)). We observed a rapid and reversible growth arrest of the cells after only 24 h of O(2) exposure. When oxidant injury was prolonged, growth arrest was followed by induction of apoptosis with activation of the Fas pathway. These effects were associated with an increased expression of IGFBP-2 and IGFBP-3. In addition, study of localization of these proteins revealed distinct patterns of distribution. IGFBP-3 was mainly present in the extracellular compartment. In comparison, the fraction of IGFBP-2 secreted was less abundant whereas the IGFBP-2 fraction in the intracellular compartment appeared stronger. In addition, analysis of the subcellular localization provided data indicating the presence of IGFBP-2 in the nucleus. Taken together these data support a role for IGFBP-2 and IGFBP-3 in the processes of growth arrest and apoptosis in lung epithelial cells upon oxidant exposure. They also suggest that distinct mechanisms may link IGFBP-2 and IGFBP-3 to the key regulators of the cell cycle.  (+info)

Mrp-dependent Na(+)/H(+) antiporters of Bacillus exhibit characteristics that are unanticipated for completely secondary active transporters. (53/413)

The Na(+)/H(+) antiport activity encoded by the seven-gene mrp operons of Bacillus subtilis and alkaliphilic Bacillus pseudofirmus OF4 were cloned into a low copy plasmid, were expressed in several Escherichia coli mutant strains and compared side-by-side with similarly cloned nhaA, a major secondary antiporter from E. coli. All three antiporter systems exhibited electron donor-dependent antiport in a fluorescence-based vesicle assay, with NhaA being the most active. In whole cells of the same antiporter-deficient strain from which the vesicles were made, E. coli KNabc, Mrp-mediated Na(+) exclusion was significantly more protonophore-resistant than that conferred by NhaA. The Mrp systems were also more efficacious than NhaA: in supporting anaerobic Na(+) resistance in wild type and a terminal oxidase mutant strain of E. coli (SBS2115); and in increasing non-fermentative growth of an NADH dehydrogenase-minus E. coli mutant (ANN0222). The results suggest the possibility that the Mrp systems may have both secondary and primary energization capacities.  (+info)

Evidence of reduced single-stranded testicular sperm DNA from obstructive azoospermic men after 3 days of in-vitro culture. (54/413)

The aim of the present study was to verify whether culturing testicular tissue, to obtain a higher percentage of motile spermatozoa and a better post-thaw recovery rate, affected the ratio between single/double-stranded sperm DNA and, consequently, DNA sensitivity to damage. Testicular biopsy samples from men with obstructive and secretory azoospermia, candidates for assisted reproductive treatment, were cultured for 72 h. The percentage of motile spermatozoa and the single/double stranded DNA ratio were assessed on the day of retrieval (day 0) and again on day 3. The single/double stranded DNA ratio was measured by the acridine orange (AO) staining method. Spermatozoa were classified as green (double-stranded chromatin) or red fluorescing (single-stranded chromatin). In obstructive azoospermia, median motility was 22% (range 10-44%) on day 0 and 50% (range 38-63%) on day 3 (P < 0.01). The median percentage of red stained spermatozoa was 53.5% (range 0.1-88%) on day 0 and 20% (range 2.7-99.9%) on day 3 (P < 0.05). No changes were observed in secretory azoospermia. The culture procedure from obstructive azoospermia not only increased the post-thaw recovery rate, as previously observed, but also reduced the portion of spermatozoa containing single-stranded DNA, thereby increasing the availability of double-stranded DNA spermatozoa for ICSI use.  (+info)

Fluorescent probes for non-invasive bioenergetic studies of whole cyanobacterial cells. (55/413)

Fluorescent DeltapH and DeltaPsi indicators have been screened for the non-invasive monitoring of bioenergetic processes in whole cells of the cyanobacterium Synechocystis sp. PCC 6803. Acridine yellow and Acridine orange proved to be the best DeltapH indicators for the investigation of thylakoid and cytoplasmic membrane energization: While Acridine yellow indicated only cytosolic energization, Acridine orange showed signals from both the thylakoid lumen and the cytosol that could be separated kinetically. Both indicators were applied successfully to monitor cellular energetics, such as the interplay of linear and cyclic photosynthetic electron transport, osmotic adaptation and solute transport across the cytoplasmic membrane. In contrast, useful membrane potential indicators were more difficult to find, with Di-4-ANEPPS and Brilliant cresyl blue being the only promising candidates for further studies. Finally, Acridine yellow and Acridine orange could also be applied successfully for the thermophilic cyanobacterium Synechococcus elongatus. Different from Synechocystis sp. PCC 6803, where both respiration and ATP hydrolysis could be utilized for cytoplasmic membrane energization, proton extrusion at the cytoplasmic membrane in Synechococcus elongatus was preferentially driven by ATP hydrolysis.  (+info)

Ca(2+) transport into an intracellular acidic compartment of Candida parapsilosis. (56/413)

In this report, we study Ca2+ transport in permeabilized Candida parapsilosis spheroplasts prepared by a new technique using lyticase. An intracellular non-mitochondrial Ca2+ uptake pathway, insensitive to orthovanadate and sensitive to the V-H(+)-ATPase inhibitor bafilomycin A(1), nigericin and carbonyl cyanide p-trifluoromethoxyphenylhydrazone was characterized. Acidification of the compartment in which Ca2+ accumulated was followed using the fluorescent dye acridine orange. Acidification was stimulated by the Ca2+ chelator EGTA and inhibited by Ca2+. These results, when added to the observation that Ca2+ induces alkalization of a cellular compartment, provide evidence for the presence of a Ca2+/nH(+) antiporter in the acid compartment membrane. Interestingly, like in acidocalcisomes of trypanosomatids, the antioxidant 3,5-dibutyl-4-hydroxytoluene inhibits the V-H(+)-ATPase. In addition, the antifungal agent ketoconazole promoted a fast alkalization of the acidic compartment. Ketoconazole effects were dose-dependent and occurred in a concentration range close to that attained in the plasma of patients treated with this drug.  (+info)