Photosynthetic electrogenic events in native membranes of Chloroflexus aurantiacus. Flash-induced charge displacements in the acceptor quinone complex of the photosynthetic reaction center

Light-dependent reduction of cystine disulfide bonds results in activation of several of the enzymes of photosynthetic carbon metabolism within the chloroplast. Tertiary structure modeling suggests that the redox-sensitivity of the chloroplast malate dehydrogenase (EC 1.1.1.82) is due to disulfide crosslinking of the carbon substrate and nucleotide-binding domains. Consistent with this suggestion, introduction of Cys residues in opposition to one another on the two domains of the Escherichia coli enzyme results in redox-sensitivity [Muslin EH et al. (1995) Biophys J 68: 2218-2223]. We have now substituted Cys residues into the bacterial malate dehydrogenase (EC 1.1.1.37) in positions that correspond more exactly to those postulated to be responsible for the redox-sensitivity of the chloroplast enzyme. The introduction of one pair of Cys residues renders the enzyme redox-sensitive, but the introduction of the alternate pair does not. Energy minimization calculations suggest that the difference in redox-sensitivity is consistent with differences in the energy required for formation of the disulfide bond.     

Frog brain expresses a 60 KDa Ca2+ binding protein similar to mammalian calreticulin

The present report was undertaken in an effort to characterize the nature of Ca2+ binding protein(s) in the central nervous system of less evolved vertebrates. In particular we investigated whether the brain microsomal fraction of Rana esculenta expresses calsequestrin, calreticulin and/or other related Ca2+ binding protein(s). We found that a 60 KDa protein having an NH2-terminal amino acid sequence similar to mammalian calreticulin is the major microsomal Ca2(+)-binding protein.     

Tissue Characterization after a New Disaggregation Method for Skin Micro-Grafts Generation

Several new methods have been developed in the field of biotechnology to obtain autologous cellular suspensions during surgery, in order to provide one step treatments for acute and chronic skin lesions. Moreover, the management of chronic but also acute wounds resulting from trauma, diabetes, infections and other causes, remains challenging. In this study we describe a new method to create autologous micro-grafts from cutaneous tissue of a single patient and their clinical application. Moreover, in vitro biological characterization of cutaneous tissue derived from skin, de-epidermized dermis (Ded) and dermis of multi-organ and/or multi-tissue donors was also performed. All tissues were disaggregated by this new protocol, allowing us to obtain viable micro-grafts. In particular, we reported that this innovative protocol is able to create bio-complexes composed by autologous micro-grafts and collagen sponges ready to be applied on skin lesions. The clinical application of autologous bio-complexes on a leg lesion was also reported, showing an improvement of both re-epitalization process and softness of the lesion. Additionally, our in vitro model showed that cell viability after mechanical disaggregation with this system is maintained over time for up to seven (7) days of culture. We also observed, by flow cytometry analysis, that the pool of cells obtained from disaggregation is composed of several cell types, including mesenchymal stem cells, that exert a key role in the processes of tissue regeneration and repair, for their high regenerative potential. Finally, we demonstrated in vitro that this procedure maintains the sterility of micro-grafts when cultured in Agar dishes. In summary, we conclude that this new regenerative approach can be a promising tool for clinicians to obtain in one step viable, sterile and ready to use micro-grafts that can be applied alone or in combination with most common biological scaffolds.     

Interference of inflammation caused by polyester with the growth of Yoshida ascite hepatoma. IV. Modifications of the sedimentation profile of the hepatoma cells

It was previously shown that Yoshida's ascites-hepatoma cells (Y cells) intraperitoneally injected into rats carrying chronic inflammation caused by polyester thread rapidly disappear. In this paper the sedimentation rate in a continuous Percoll gradient at unit gravity (1 g) using the CELSEP apparatus (Sorvall), the mean diameter and volume of the Y cells harvested from the peritoneal cavity of untreated (NT) and polyester-treated (TM) animals were determined at 6-12-18-24 hours after the inoculum. At 6 hours a number of Y cells appeared enlarged both from TM and NT rats, while afterwards, and notably at 18 and 24 hours, their size was decreased and their sedimentation rate was reduced only in TM animals. It seems that the chronic inflammation causes alterations both in the size and in the density of the Y cells and probably one of the mechanisms of their death is through shrinkage and apoptosis.     

Reduced oxidative activity of circulating neutrophils in patients after myocardial infarction

Circulating neutrophils isolated from patients 3–4 h after a myocardial infarction produced less $ {\rm O}\frac{ \cdot }{{\rm 2}} $ compared with controls, when stimulated with phorbol myrystate acetate or formyl-methionine-leucine-phenylalanine. Three days after the infraction the $ {\rm O}\frac{ \cdot }{{\rm 2}} $ generation elicited by both stimuli further decreased markedly. Seven and 15 days after infarction the $ {\rm O}\frac{ \cdot }{{\rm 2}} $ stimulated production was only slightly lower than or similar to the control values. The neutrophils of infarcted patients showed an augmented latency period before $ {\rm O}\frac{ \cdot }{{\rm 2}} $ production compared with controls in response to exogenous stimuli, particularly three days after infarction. Electron microscopy revealed that the neutrophils isolated from the infarcted patients displayed signs of cell exhaustion with few alterations of the plasma membranes when stimulated with phorbol ester. In contrast, control neutrophils displayed alterations of the plasma membranes characteristic of active neutrophils. The results of this study indicate that the circulating neutrophils appear exhausted and functionally inhibited immediately after myocardial infarction.     

Long-term continuous intraperitoneal insulin treatment in brittle diabetes.

Attempts to achieve a fair metabolic equilibrium in a young woman with brittle diabetes by continuous subcutaneous, intramuscular, and continuous intravenous administration of insulin were unsuccessful. Continuous intraperitoneal administration of insulin through a permanently inserted polyethylene catheter connected to an open-loop peristaltic pump led to an appreciable improvement in mean blood glucose concentration, mean amplitude of glycaemic excursions, and M value and to normalisation of intermediate metabolic products. The peritoneal catheter was well tolerated for over 120 days without appreciable adverse effects. This case suggests that long-term intraperitoneal administration of insulin is a feasible therapeutic approach in the management of brittle diabetes.     

Inflammatory reaction to polyester material in the guinea pig. V. Semiautomatic determination of peritoneal cell volume

The volume of the peritoneal cells of guinea pigs treated with injections of 1) minced polyester threads (Mersilene), 2) saline, and of untreated animals, has been determined utilizing a Coulter Counter coupled with a pulse height analyzer. The volumetric test on the whole cell population has emphasized a distinctly bimodal distribution, due to the presence of two cellular types picked out as first peak (P 1 degrees) and second peak (P 2 degrees), while the non-adherent cells (CNA) have shown an unimodal distribution. Statistically significant difference in the mean volumes have been found between the P 1 degrees and P 2 degrees cells and between the CNA and P 1 degrees cells. The percentage of CNA in the whole cell population significantly decreases in "Mersilene"-treated guinea pigs.     

Energy transduction in photosynthetic bacteria. VIII. Activation of the energy-transducing ATPase by inorganic phosphate.

ATPase activity and ATP-induced energization of photosynthetic membranes from Rhodopseudomonas capsulata are stimulated by phosphate; the maximum stimulatory effect occurs at a concentration between 1 and 2 mM. The sensitivity of the ATPase to oligomycin increases in the presence of phosphate since all the Pi-stimulated activity is inhibited by this antibiotic. Aurovertin, which has no effect on ATPase in the absence of phosphate, inhibits completely the activity elicited by this anion. The addition of Pi induces a substantial increase in the V of ATPase activity without changing the affinity of the enzyme for ATP or ADP. Arsenate, at the same concentrations, produces effects very similar to those of phosphate. The stimulation by arsenate of the transfer of energy from ATP to the membrane suggests a non-hydrolytic role of this anion as a modifier of the ATPase activity.