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1.
FAVE, Secc. Cienc. vet. (En línea) ; 14(1/2): 38-41, Dec. 2015. ilus
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1090330

ABSTRACT

La leptospirosis en equinos es generalmente asintomática, aunque existen regiones donde la enfermedad constituye un problema. Aquí se describe un caso de aborto en yegua debido a la infección por este agente. Se efectuó la necropsia completa de un feto a término donde se colectaron muestras para inmunofluorescencia directa (IFD), histopatología y microbiología. Además, se efectuó un estudio serológico de la tropilla y se evaluó seroconversión en la yegua abortada. El feto evidenció hepatomegalia, esplenomegalia e ictericia. Microscópicamente se apreció hepatitis mononuclear con disociación de los hepatocitos, esplenitis aguda y glomérulonefritis. Aunque el microrganismo no pudo ser aislado, la enfermedad se confirmó por la seroconversión observada en la yegua abortada, y debido a la identificación del agente mediante IFD en la impronta renal. Este caso demuestra la presencia del agente localmente y evidencia que la enfermedad puede ser un problema para la producción ecuestre.


Leptospirosis in horses is usually asymptomatic, although there are regions where the disease is a problem. Here, a case of abortion caused by the agent in a mare is described. Full autopsy of a fetus at term was performed; samples for direct immunofluorescence (DIF), histopathology and microbiology were collected. Additionally, a serological study of the herd was conducted, as well as seroconversion in the aborted mare. The fetus evidenced hepatomegaly, splenomegaly and jaundice. Microscopically, mononuclear hepatitis with hepatocyte dissociation, acute splenitis and glomerulonephritis, were appreciated. Although the microorganism couldn't be quite properly, the disease was confirmed by the seroconversion present in the aborted mare. Another factor was the identification of the agent through the renal imprint DIF. This case demonstrates the presence of the agent mentioned locally, and evidences that the disease can represent a problem to the equestrian industry.

2.
Int Angiol ; 30(1): 64-70, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21248675

ABSTRACT

AIM: Deep vein thrombosis (DVT) is an insidious disease wherein more than 15 different clinical signs are described. The aim of this work was to focus on these clinical signs and to test them for their importance in making a diagnosis of DVT. METHODS: All patients treated with a tentative diagnosis of DVT in the emergency department were asked to take part in the study. Out of the 254 patients who were examined in order to exclude DVT, 204 patients agreed to participate in the study. The patients who agreed to take part were tested for fifteen clinical examination signs. The Wells score was then determined. RESULTS: Sixty-two were diagnosed with DVT. For 142 patients, DVT could be ruled out. The probability of DVT for 9 signs together is 88%, and for 3 signs is 78%. The negative predictive values are 91-95%. The combination of the clinical signs showed a specificity of 100%, independent if the patients were old, comorbid, and were diagnosed with the thrombosis in the lower limbs. The determination of the Wells score resulted in no convincing evidence for or against the diagnosis of DVT. CONCLUSION: We suggest a modified Wells score integrating missing clinical signs with more reliable predictive values. Even with the availability of ultrasound, clinical signs have not become superfluous. They are quick to carry out, safe, cheap and an important addition to the Wells score, particularly for multimorbid and elderly patients.


Subject(s)
Diagnostic Techniques, Cardiovascular , Venous Thrombosis/diagnosis , Adult , Aged , Aged, 80 and over , Emergency Service, Hospital , Female , Germany , Hospitals, University , Humans , Male , Middle Aged , Predictive Value of Tests , Prognosis , Risk Assessment , Risk Factors , Sensitivity and Specificity , Young Adult
8.
Med Klin (Munich) ; 96(6): 321-4, 2001 Jun 15.
Article in German | MEDLINE | ID: mdl-11450583

ABSTRACT

BACKGROUND: Diagnostic or therapeutic paracentesis of ascites or pleural effusions is part of the daily routine on many hospital wards and in outpatient clinics. In Germany, paracentesis is usually performed with angiocaths. However, the therapeutic large volume paracentesis of ascites and paracentesis of pleural effusions with angiocaths is often cumbersome and quite often paracentesis fails, forcing the physician to repuncture. This is mainly due to the fact that angiocaths are not designed for such interventions. PATIENTS AND METHOD: 45 patients with ascites or pleural effusions were treated with a new needle specially designed for paracentesis, or with an angiocath. The new paracentesis needle was compared with the angiocath needle under the following aspects: necessity and number of positional corrections of the needle, necessity of and reasons for repuncture, duration of puncture, flow capacity, subjective practicability of paracentesis and patient acceptance of the paracentesis needle. RESULTS: The paracentesis needle was superior to the angiocath in all investigated respects. Significantly, the paracentesis needle had a much higher success rate in the complete drainage than had the angiocath. CONCLUSION: The paracentesis needle was objectively superior as compared to the angiocath. It might help to avoid additional complications due to repuncture and it will increase the patients' comfort.


Subject(s)
Ascites/therapy , Catheters, Indwelling , Needles , Paracentesis/instrumentation , Pleural Effusion/therapy , Adult , Aged , Cross-Over Studies , Female , Humans , Male , Middle Aged , Treatment Outcome
9.
Eur J Gastroenterol Hepatol ; 12(6): 679-85, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10912489

ABSTRACT

BACKGROUND: Lipopolysaccharides (LPSs) are thought to be one of the triggers of organ reactions to sepsis, which causes hepatocellular dysfunction. This dysfunction can be demonstrated by a reduction of organic anion transport. The aim of our study was to assess whether the transport of indocyanine green (ICG) is affected by LPS, and whether Kupffer cells are involved. METHODS: Single-pass liver perfusion with ICG at a concentration of 57.8 mg/kg/min was performed for 130 min. pH, oxygen tension and perfusion pressure were continuously measured in influent and effluent. Taurocholate was infused at 48.3 mg/kg/min to achieve a stable bile flow. LPS was added at concentrations of 0.45, 0.9 and 1.44 mg/kg/min for 30 min. ICG was determined photometrically in perfusate and bile. To depress the function of Kupffer cells male Wistar rats were treated with GdCl3 24 h in advance. Primary cultured hepatocytes were used for studying the direct effect of LPS on the uptake rate of ICG. RESULTS: Forty-five minutes after administration of LPS a significant dose-dependent decrease of ICG uptake was seen in animals treated with LPS. Livers of animals pretreated with GdCl3 did not show this decrease. LPS had no direct effect on the uptake of ICG into primary cultured hepatocytes, whereas treatment of these cells with 8-bromo-cGMP resulted in a significant increase of ICG uptake. CONCLUSION: LPS has a rapid dose-dependent effect on the detoxification properties of the liver for ICG. The rapid effect of LPS on ICG uptake in hepatocytes is mediated by Kupffer cells.


Subject(s)
Cyclic GMP/analogs & derivatives , Indocyanine Green/pharmacokinetics , Lipopolysaccharides/pharmacology , Liver/metabolism , Animals , Cells, Cultured , Cyclic GMP/pharmacology , Dose-Response Relationship, Drug , Gadolinium/pharmacology , Kupffer Cells/drug effects , Kupffer Cells/metabolism , Kupffer Cells/physiology , Liver/cytology , Liver/drug effects , Male , Phagocytosis/drug effects , Rats , Rats, Wistar
10.
BMJ ; 319(7214): 881-4, 1999 Oct 02.
Article in English | MEDLINE | ID: mdl-10506041

ABSTRACT

OBJECTIVE: To determine the efficacy of antibacterial prophylaxis in preventing infectious complications after percutaneous endoscopic gastrostomy. DESIGN: Prospective, randomised, placebo controlled, double blind, multicentre study. SETTING: Departments of internal medicine at six German hospitals. SUBJECTS: Of 106 randomised adult patients with dysphagia, 97 received study medication, and 84 completed the study. The median age of the patients was 65 years. Most had dysphagia due to malignant disease (65%), and many (76%) had serious comorbidity. INTERVENTIONS: A single intravenous 2.2 g dose of co-amoxiclav or identical appearing saline was given 30 min before percutaneous endoscopic gastrostomy performed by the thread pull method. MAIN OUTCOME MEASURES: Occurrence of peristomal wound infections and other infections within one week after percutaneous endoscopic gastrostomy. RESULTS: The incidence of peristomal and other infections within one week after percutaneous endoscopic gastrostomy was significantly reduced in the antibiotic group (8/41 (20%) v 28/43 (65%), P<0.001). Similar results were obtained in an intention to treat analysis. Several peristomal wound infections were of minor clinical significance. After wound infections that required no or only local treatment were excluded from the analysis, antibiotic prophylaxis remained highly effective in reducing clinically important wound infections (1/41 (2%) v 11/43 (26%), P<0.01) and non-wound infections (2 (5%) v 9 (21%), P<0.05). CONCLUSIONS: Antibiotic prophylaxis with a single dose of co-amoxiclav significantly reduces the risk of infectious complications after percutaneous endoscopic gastrostomy and should be recommended.


Subject(s)
Amoxicillin-Potassium Clavulanate Combination/administration & dosage , Antibiotic Prophylaxis , Deglutition Disorders/surgery , Drug Therapy, Combination/administration & dosage , Gastroscopy/methods , Gastrostomy/methods , Administration, Oral , Adult , Aged , Aged, 80 and over , Double-Blind Method , Humans , Middle Aged , Prospective Studies
11.
Hepatology ; 29(4): 1280-7, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10094976

ABSTRACT

Interleukin-12 (IL-12) plays a central role in mounting an effective cellular immune response directed towards elimination of intracellular pathogens. The present open-label, multicenter, dose-escalation phase I/II study was designed to assess tolerability, pharmacokinetics, pharmacodynamics, and efficacy of subcutaneously administered recombinant human interleukin-12 (rHuIL-12) in the treatment of chronic hepatitis C. Sixty patients (42 men, 18 women, aged 24-60) were treated with 0.03 microgram/kg (n = 16), 0.1 microgram/kg (n = 14), 0.25 microgram/kg (n = 15), or 0.5 microgram/kg rHuIL-12 (n = 15) for 10 consecutive weeks. rHuIL-12 was generally well tolerated, with 2 patients (3.3%) being withdrawn from treatment for adverse events. Treatment was associated with temporary decreases in neutrophils and lymphocyte counts and with elevations in serum transaminases and bilirubin. Serum IL-12 levels observed were higher at 0.5 microgram/kg compared with 0.25 microgram/kg doses, suggesting a dose-related increase in systemic exposure of IL-12. Measurable levels of interferon gamma (IFN-gamma) were also observed at the highest dose of 0.5 microgram/kg. At the end of treatment hepatitis C virus (HCV) RNA was detectable in all patients. A more than 50% decrease in pretreatment HCV RNA levels was observed in 3 of 16 patients of the 0.03-microgram/kg dose group, in 3 of 14 of the 0.10-microgram/kg dose group, in 6 of 15 of the 0.25-microgram/kg dose group, and in 8 of 15 patients of the 0.5-microgram/kg dose group. Although in several cases serum alanine transaminase (ALT) levels decreased either during or after treatment, ALT normalization was observed in only 4 patients at the end of treatment and in 5 patients at the end of follow-up. Significant anti-rHuIL-12 antibody titers were not detectable in any patient. In conclusion, antiviral activity of rHuIL-12 in patients with chronic hepatitis C does not appear advantageous in comparison with other currently available treatments.


Subject(s)
Hepatitis C, Chronic/drug therapy , Interleukin-12/therapeutic use , Recombinant Proteins/therapeutic use , Adolescent , Adult , Alanine Transaminase/blood , Antibodies/blood , Dose-Response Relationship, Drug , Female , Hepatitis C, Chronic/blood , Humans , Interferon-gamma/blood , Interleukin-10/blood , Interleukin-12/adverse effects , Interleukin-12/immunology , Interleukin-12/pharmacokinetics , Male , Middle Aged , Neopterin/blood , RNA, Viral/blood , Recombinant Proteins/adverse effects , Recombinant Proteins/immunology , Recombinant Proteins/pharmacokinetics , Viremia/drug therapy , beta 2-Microglobulin/metabolism
13.
Dtsch Med Wochenschr ; 121(30): 939-42, 1996 Jul 26.
Article in German | MEDLINE | ID: mdl-8765702

ABSTRACT

HISTORY AND CLINICAL FINDINGS: Two months after being diagnosed as having refractory anaemia with an excess of blasts in transformation (RAEB-T), a 62-year-old man presented in the emergency room with fever (40 degrees C) for two weeks and scattered deep-red macular indolent efflorescences over the chest, back, face and thighs. Other than splenomegaly there were no significant findings on physical examination. INVESTIGATIONS: Erythrocyte sedimentation rate was increased to 38 mm in the first hour. Haemoglobin concentration and platelet count were at the lower limits of normal, white cell count within the normal range. Differential count: 60 erythroblasts per 100 leukocytes and 33.5 blast cells. Two skin biopsies revealed massive oedema in the upper corium and focal erythrocyte extravasations. There were perivascular and perifollicular inflammatory infiltrates in the deeper layers and elastosis of the corium. There was no leukocytoclastic vasculitis. These findings established the diagnosis of Sweet syndrome and erythroleukaemia. TREATMENT AND COURSE: The erythroleukaemia was treated symptomatically and the skin changes gradually receded under prednisone, 1 mg/kg, but new spots occurred when the prednisone dose was halved. Candida oesophagitis occurred as a complication of the erythroleukaemia. Chest radiogram showed diffuse infiltrates in both upper lobes of the lung. Despite intensive antimycotic and antibiotic treatment the patient died 10 days later from pulmonary aspergillosis. CONCLUSION: This case report describes the rare occurrence of Sweet syndrome during the transformation from a myelodysplastic Syndrome to erythroleukaemia.


Subject(s)
Anemia, Refractory, with Excess of Blasts/diagnosis , Leukemia, Erythroblastic, Acute/diagnosis , Sweet Syndrome/diagnosis , Anemia, Refractory, with Excess of Blasts/complications , Anemia, Refractory, with Excess of Blasts/therapy , Aspergillosis/pathology , Candidiasis/pathology , Combined Modality Therapy , Diagnosis, Differential , Esophagitis/pathology , Fatal Outcome , Humans , Leukemia, Erythroblastic, Acute/complications , Leukemia, Erythroblastic, Acute/therapy , Lung Diseases, Fungal/pathology , Male , Middle Aged , Recurrence , Sweet Syndrome/complications , Sweet Syndrome/therapy , Time Factors
14.
Am J Physiol ; 270(3 Pt 1): G418-24, 1996 Mar.
Article in English | MEDLINE | ID: mdl-8638707

ABSTRACT

The effect of guanosine 3',5'-cyclic monophosphate (cGMP) on hepatic bile formation was studied in isolated perfused rat livers and rat hepatocytes. Studies in isolated perfused rat livers showed that infusion of 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP, 3 micromol/min or 100 microM) 1) increased bile flow without affecting biliary excretion of simultaneously infused taurocholate, 2) increased biliary concentration and excretion of HCO3(-) but did not affect biliary excretion of glutathione, and 3) increased net perfusate H+ efflux without affecting hepatic O2 uptake. Studies in isolated rat hepatocytes showed that 1) 8-BrcGMP increased intracellular pH in the presence (but not in the absence) of extracellular HCO-3, and effect inhibited by 4,4' -diisothiocyanostilbene-2,2'-disulfonic acid and Na+ replacement, 2) 8-BrcGMP did not affect taurocholate uptake and intracellular [Ca2+], and 3) bile acids, like ursodeoxycholate and cholate, did not increase cellular cGMP. Taken together, these results indicate that cGMP stimulates bile acid-independent bile formation, in part by stimulating biliary HCO3- excretion. cGMP may increase HCO3- excretion by stimulating sinusoidal Na+ - HCO3- cotransport, but not Na+/H+ exchange. cGMP, unlike adenosine 3',5'-cyclic monophosphate, may not regulate hepatic taurocholate transport, and bile acid-induced HCO3- rich choleresis may not be mediated via cGMP.


Subject(s)
Bicarbonates/metabolism , Bile Acids and Salts/metabolism , Bile Acids and Salts/pharmacology , Bile/physiology , Cyclic GMP/analogs & derivatives , Cyclic GMP/physiology , Liver/physiology , 1-Methyl-3-isobutylxanthine/pharmacology , 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid/pharmacology , Amiloride/pharmacology , Animals , Arginine Vasopressin/pharmacology , Bile/metabolism , Calcium/metabolism , Cells, Cultured , Choline/pharmacology , Cyclic AMP/analogs & derivatives , Cyclic AMP/pharmacology , Cyclic GMP/pharmacology , Glutathione/metabolism , Hydrogen-Ion Concentration , In Vitro Techniques , Kinetics , Liver/drug effects , Male , Oxygen Consumption/drug effects , Rats , Rats, Wistar , Taurocholic Acid/metabolism , Taurocholic Acid/pharmacology , Thionucleotides/pharmacology , Ursodeoxycholic Acid/pharmacology
15.
FEBS Lett ; 382(1-2): 171-4, 1996 Mar 11.
Article in English | MEDLINE | ID: mdl-8612744

ABSTRACT

Two conserved charged amino acids of the N-terminal 'crown' region of the alpha subunit of E. coli-F(1), alpha-D36 and alpha-R40 were exchanged for chemically related (alpha-D36-->E, alpha-R40-->K) or unrelated amino acids (alpha D-36-->K, alpha R40-->G), respectively, by employing oligonucleotide-directed mutagenesis. ATP formation and ATP hydrolyzing activity of isolated plasma membrane vesicles was strongly inhibited in mutant HS2 (alpha-D36-->K), but only slightly affected in the other mutants. The inhibition is not due to a lower content of F0F1 in HS2. In this mutant the extent of the proton gradient generated by ATP hydrolysis was more than 80% inhibited; in all other transformants much smaller effects were observed. The proton gradient established by NADH oxidation was 33% decreased in HS2, but was decreased to a lesser extent in all other mutants. After blockage of F0 by DCCD treatment, the same NADH-induced proton gradient was obtained in all transformants including HS2. This and the fact that the activity of NADH oxidation was unchanged indicate increased proton leakiness of F0F1 carrying the alpha-D36-->K mutation. In F1 alpha-D36 is located in a domain contacting the beta subunit in the vicinity of the arginine beta-R52. The effect of alpha-D36-->K replacement on catalysis and coupling thus may be due to an electrostatic repulsive effect in the crown region which alters the alpha and beta interaction.


Subject(s)
Arginine/physiology , Aspartic Acid/physiology , Escherichia coli/enzymology , Proton-Translocating ATPases/metabolism , Adenosine Triphosphate/metabolism , Amino Acid Sequence , Base Sequence , Cell Membrane/metabolism , Conserved Sequence , Dicyclohexylcarbodiimide/pharmacology , Escherichia coli/growth & development , Hydrolysis , Molecular Sequence Data , Mutagenesis, Site-Directed , NAD/metabolism , Oxidation-Reduction , Proton Pumps/metabolism , Proton-Translocating ATPases/chemistry , Proton-Translocating ATPases/genetics
16.
Am J Physiol ; 270(2 Pt 1): G339-46, 1996 Feb.
Article in English | MEDLINE | ID: mdl-8779977

ABSTRACT

Elevation of intracellular adenosine 3',5'-cyclic monophosphate (cAMP) hyperpolarizes hepatocytes and increases the uptake rate of bile acids. The purpose of this study was to determine to what extent these two phenomena are linked. Fluorescent bile acid analogues (FBA) were used to probe bile acid transport into whole cell patch-clamped hepatocytes. Na(+)-dependent uptake of cholyl-nitrobenz-2-oxa-1,3-diazol-4-yl-lysine (C-NBD-L), an FBA with a net charge of -1, was shown to be electrogenic, whereas uptake of cholylglycylamidofluorescein (CGamF), an FBA with a net charge of -2, was neutral. Incubation of hepatocytes with 8-bromo-cAMP (8-BrcAMP; 100 microM) increased the uptake rate of the electrogenically transported FBA by 25% (P = 0.002), but had no effect on the uptake rate of the electroneutrally transported FBA. Microelectrode impalements revealed that 8-BrcAMP or forskolin hyperpolarized hepatocytes by 6-8 mV. To determine if hyperpolarization is responsible for the cAMP-induced increase in uptake rate, cAMP was directly introduced into hepatocytes during whole cell patch clamp under voltage-clamp conditions. As long as voltage clamp was maintained at -30 mV there was no stimulation of C-NBD-L uptake. However, when voltage clamp was terminated by either pipette removal or current clamp, cAMP increased the uptake rate by 25-34% (P < 0.002). In both of these protocols, cAMP had no effect on uptake of the electroneutrally transported FBA, CGamF. Finally, in voltage-clamped hepatocytes in the absence of cAMP, a 10-mV hyperpolarization increased the uptake rate of C-NBD-L by 23%. We therefore conclude that short-term cAMP-induced stimulation of fluorescent bile acid uptake in hepatocytes is a direct consequence of membrane hyperpolarization.


Subject(s)
Cholic Acids/pharmacokinetics , Cyclic AMP/pharmacology , Liver/physiology , Lysine/analogs & derivatives , Animals , Cell Membrane/physiology , Electrophysiology , Fluorescent Dyes , Liver/cytology , Lysine/pharmacokinetics , Microscopy, Fluorescence , Patch-Clamp Techniques , Rats
18.
Clin Investig ; 72(12): 979-84, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7711431

ABSTRACT

Since 1974 primary aldosteronism has been diagnosed in 71 patients in our outpatient clinic. Thirty-four patients had a unilateral aldosterone-producing adenoma, whereas bilateral adrenal hyperplasia was diagnosed in 37 patients. Although at the time of diagnosis the mean potassium values were lower and mean aldosterone levels were higher in patients with an adenoma, as compared to those with bilateral hyperplasia, these laboratory data did not allow us to differentiate between the two leading causes of primary aldosteronism in the individual patient due to pronounced overlap of laboratory values between the two groups. During the first few years, a successful differential diagnosis was made by adrenal phlebography and separate sampling of plasma aldosterone in both adrenal veins; later non-invasive imaging techniques such as computed tomography and radionuclide scanning were used. The best results were obtained in patients with adenoma who underwent adrenalectomy. Fifty-six percent of these patients were clinically and biochemically cured; 28% were improved and had normal blood pressure values during drug treatment. In contrast, patients with bilateral hyperplasia were treated pharmacologically, but only in half of the patients could normal blood pressure values be achieved. Two thirds of the male patients developed gynecomastia during spironolactone treatment. As expected, unilateral adrenalectomy was unsuccessful in the 7 patients with bilateral hyperplasia who underwent surgery. Our results confirm that surgical treatment of adrenal adenomas and drug treatment of bilateral hyperplasias are the appropriate therapy in primary aldosteronism. A differential diagnosis cannot be made on the basis of clinical and non-invasive laboratory data alone; imaging techniques have to be included in the diagnostic process.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Adenoma/diagnosis , Adrenal Gland Neoplasms/diagnosis , Adrenal Glands/pathology , Hyperaldosteronism/diagnosis , Spironolactone/therapeutic use , Adult , Aged , Diagnosis, Differential , Follow-Up Studies , Humans , Hyperplasia/diagnosis , Hyperplasia/drug therapy , Male , Middle Aged , Treatment Outcome
19.
Schweiz Rundsch Med Prax ; 83(27-28): 792-6, 1994 Jul 05.
Article in German | MEDLINE | ID: mdl-8047757

ABSTRACT

In this study the most important Swiss studies on the incidence of overweight and obesity are summarized and compared to the corresponding prevalence rates from the Heureka study. Interestingly, data on body weight indexes (mostly mass indexes) and the various prevalence rates showed good accordance for younger age groups. In the upper age classes however, phenotypic differences concerning determinants and risk factors for overweight became obvious in the different Swiss populations (i.e. from geographically different regions of Switzerland). Nevertheless, regional risk factors could not been detected because specific data were lacking. The importance of uniform weight definitions for studies as well as for daily practise is stressed.


Subject(s)
Body Mass Index , Obesity/epidemiology , Obesity/physiopathology , Adult , Aged , Epidemiologic Methods , Female , Humans , Incidence , Longitudinal Studies , Male , Middle Aged , Switzerland/epidemiology
20.
Mol Gen Genet ; 244(2): 144-50, 1994 Jul 25.
Article in English | MEDLINE | ID: mdl-8052233

ABSTRACT

A regulatory sequence in the gamma subunit of the F0F1-ATPase complex of higher plant chloroplasts, responsible for so-called thiol modulation, is absent in the corresponding polypeptides of the cyanobacterial complexes analysed so far. We have modified the atpC gene encoding this gamma subunit in Synechocystis 6803 by site-directed mutagenesis. A segment was introduced coding for nine additional amino acids, including the two functional cysteines, which constitutes the sequence of the respective element in the chloroplast gamma subunit. The growth rate as well as the rate of photosynthesis of the transformant was comparable to that of the wild-type, but the transitory increase in respiration observed immediately after a period of illumination was significantly lower in the mutant than in the wild-type. The F1 subcomplex solubilized from thylakoid membranes of both the wild-type and the transformant can be activated by trypsin to yield Ca(2+)-dependent ATPase activity, but only the F1 from the transformant can be activated by the thiol reagent dithiothreitol.


Subject(s)
Chloroplasts/enzymology , Cyanobacteria/enzymology , Cyanobacteria/genetics , Genes, Bacterial , Mutagenesis, Insertional , Amino Acid Sequence , Base Sequence , Blotting, Southern , DNA Primers , DNA, Bacterial/analysis , Darkness , Glucose/pharmacology , Light , Macromolecular Substances , Molecular Sequence Data , Oxygen Consumption/drug effects , Polymerase Chain Reaction , Regulatory Sequences, Nucleic Acid , Sequence Homology, Amino Acid , Sequence Homology, Nucleic Acid , Vegetables/enzymology , Vegetables/genetics
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