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1.
Endocrine ; 82(3): 613-621, 2023 12.
Article En | MEDLINE | ID: mdl-37490266

BACKGROUND: Familial papillary thyroid microcarcinoma (FPTMC) appears to be more aggressive than sporadic papillary thyroid microcarcinoma (SPTMC). However, there are authors who indicate that unicentric FPTMC has a similar prognosis to SPTMC. The objective is to analyze whether unicentric FPTMC has a better prognosis than multicentric FPTMC. DESIGN AND METHODS: Type of study: National multicenter longitudinal analytical observational study. STUDY POPULATION: Patients with FPTMC. STUDY GROUPS: Two groups were compared: Group A (unicentric FPTMC) vs. Group B (multicentric FPTMC). STUDY VARIABLES: It is analyzed whether between the groups there are: a) differentiating characteristics; and b) prognostic differences. STATISTICAL ANALYSIS: Cox regression analysis and survival analysis. RESULTS: Ninety-four patients were included, 44% (n = 41) with unicentric FPTMC and 56% (n = 53) with multicentric FPTMC. No differences were observed between the groups according to socio-familial, clinical or histological variables. In the group B a more aggressive treatment was performed, with higher frequency of total thyroidectomy (99 vs. 78%; p = 0.003), lymph node dissection (41 vs. 15%; p = 0.005) and therapy with radioactive iodine (96 vs. 73%; p = 0.002). Tumor stage was similar in both groups (p = 0.237), with a higher number of T3 cases in the group B (24 vs. 5%; p = 0.009). After a mean follow-up of 90 ± 68.95 months, the oncological results were similar, with a similar disease persistence rate (9 vs. 5%; p = 0.337), disease recurrence rate (21 vs. 8%; p = 0.159) and disease-free survival (p = 0.075). CONCLUSIONS: Unicentric FPTMC should not be considered as a SPTMC due to its prognosis is similar to multicentric FPTMC.


Carcinoma, Papillary , Thyroid Neoplasms , Humans , Thyroid Neoplasms/genetics , Thyroid Neoplasms/therapy , Thyroid Neoplasms/pathology , Iodine Radioisotopes/therapeutic use , Neoplasm Recurrence, Local/drug therapy , Carcinoma, Papillary/pathology , Prognosis , Thyroidectomy/methods , Retrospective Studies
2.
Langenbecks Arch Surg ; 407(8): 3631-3642, 2022 Dec.
Article En | MEDLINE | ID: mdl-36251077

PURPOSE: Familial papillary thyroid microcarcinoma (FPTMC) can present a more aggressive behavior than the sporadic microcarcinoma. However, few studies have analyzed this situation. The objective is to analyze the recurrence rate of FPTMC and the prognostic factors which determine that recurrence in Spain. METHODS: Spanish multicenter longitudinal analytical observational study was conducted. Patients with FPTMC received treatment with curative intent and presented cure criteria 6 months after treatment. Recurrence rate and disease-free survival (DFS) were analyzed. Two groups were analyzed: group A (no tumor recurrence) vs. group B (tumor recurrence). RESULTS: Ninety-four patients were analyzed. During a mean follow-up of 73.3 ± 59.3 months, 13 recurrences of FPTMC (13.83%) were detected and mean DFS was 207.9 ± 11.5 months. There were multifocality in 56%, bilateral thyroid involvement in 30%, and vascular invasion in 7.5%; that is to say, they are tumors with histological factors of poor prognosis in a high percentage of cases. The main risk factors for recurrence obtained in the multivariate analysis were the tumor size (OR: 2.574, 95% CI 1.210-5.473; p = 0.014) and the assessment of the risk of recurrence of the American Thyroid Association (ATA), both intermediate risk versus low risk (OR: 125, 95% CI 10.638-1000; p < 0.001) and high risk versus low risk (OR: 45.454, 95% CI 5.405-333.333; p < 0.001). CONCLUSION: FPTMC has a recurrence rate higher than sporadic cases. Poor prognosis is mainly associated with the tumor size and the risk of recurrence of the ATA.


Carcinoma, Papillary , Thyroid Neoplasms , Humans , Carcinoma, Papillary/genetics , Carcinoma, Papillary/pathology , Thyroid Neoplasms/genetics , Thyroid Neoplasms/surgery , Disease-Free Survival , Prognosis , Retrospective Studies , Neoplasm Recurrence, Local/genetics , Neoplasm Recurrence, Local/pathology
3.
Med Biol Eng Comput ; 56(8): 1379-1390, 2018 Aug.
Article En | MEDLINE | ID: mdl-29318442

The present paper aims at presenting the methodology and first results of a detection system of risk of diabetic macular edema (DME) in fundus images. The system is based on the detection of retinal exudates (Ex), whose presence in the image is clinically used for an early diagnosis of the disease. To do so, the system applies digital image processing algorithms to the retinal image in order to obtain a set of candidate regions to be Ex, which are validated by means of feature extraction and supervised classification techniques. The diagnoses provided by the system on 1058 retinographies of 529 diabetic patients at risk of having DME show that the system can operate at a level of sensitivity comparable to that of ophthalmological specialists: it achieved 0.9000 sensitivity per patient against 0.7733, 0.9133 and 0.9000 of several specialists, where the false negatives were mild clinical cases of the disease. In addition, the level of specificity reached by the system was 0.6939, high enough to screen about 70% of the patients with no evidence of DME. These values show that the system fulfils the requirements for its possible integration into a complete diabetic retinopathy pre-screening tool for the automated management of patients within a screening programme. Graphical Abstract Diagnosis system of risk of diabetic macular edema (DME) based on exudate (Ex) detection in fundus images.


Algorithms , Diabetic Retinopathy/diagnosis , Exudates and Transudates/diagnostic imaging , Image Processing, Computer-Assisted , Macular Edema/diagnosis , Automation , Humans , ROC Curve , Risk Factors , Sensitivity and Specificity
4.
Ann R Coll Surg Engl ; 96(7): e8-10, 2014 Oct.
Article En | MEDLINE | ID: mdl-25245714

The primitive thymus and inferior parathyroid derive from the third branchial cleft. During embryonic development, these structures descend, reaching their final localisation. Third branchial cleft anomalies present usually as a fistula, abscess or cyst. However, there are no reports on parathyroid adenomas in the literature other than as a morphological possibility. We describe the case of a 47-year-old man, who had been diagnosed with arterial hypertension and who presented with a cervical mass at the edge of the lower third of the sternocleidomastoid muscle. On ultrasonography, the mass had a cystic walled appearance. Laboratory analysis only revealed an intact parathyroid hormone level of 140.5 pg/ml. Sestamibi imaging showed a probable parathyroid adenoma in the anterior mediastinum. During surgery, a tract running from beyond the superior thyroid pedicle to the superior mediastinum was dissected and removed. In the inferior end of the tract, a brown mass was visible. Pathological examination revealed a thymus cyst surrounding a parathyroid adenoma. The primal alteration was the lack of division between the thymus and inferior parathyroid gland, and the prompt prevention of their development. In the case of our patient, a parathyroid adenoma had grown by chance.


Adenoma/diagnostic imaging , Hyperparathyroidism/etiology , Parathyroid Neoplasms/diagnostic imaging , Parathyroidectomy/methods , Adenoma/complications , Adenoma/surgery , Contrast Media , Cysts/complications , Cysts/diagnostic imaging , Follow-Up Studies , Humans , Hyperparathyroidism/diagnostic imaging , Hyperparathyroidism/surgery , Male , Middle Aged , Parathyroid Neoplasms/complications , Parathyroid Neoplasms/surgery , Pharyngeal Diseases/complications , Pharyngeal Diseases/diagnostic imaging , Rare Diseases , Risk Assessment , Technetium Tc 99m Sestamibi , Thoracotomy/methods , Treatment Outcome , Ultrasonography, Doppler/methods
5.
Ann R Coll Surg Engl ; 95(2): e25-6, 2013 Mar.
Article En | MEDLINE | ID: mdl-23484975

Surgery for persistent primary hyperparathyroidism remains a major challenge for surgeons and these reoperative procedures require an experienced parathyroid surgeon. The goal of reoperative surgery is to excise the abnormal parathyroid gland(s) and limit exploration to help minimise the potential complications. At least two positive and concordant localising studies should be available before reoperation because the technical difficulties in these cases make an exact localisation necessary before surgery. We describe the placement of a metallic harpoon under ultrasonography guidance as a safe, simple and inexpensive technique for localisation of the enlarged gland prior to conservative surgery.


Adenoma/surgery , Fiducial Markers , Hyperparathyroidism, Primary/surgery , Neoplasm Recurrence, Local/surgery , Parathyroid Neoplasms/surgery , Parathyroidectomy/instrumentation , Chronic Disease , Humans , Male , Middle Aged , Preoperative Care/instrumentation , Reoperation/instrumentation , Ultrasonography, Interventional
6.
J Colloid Interface Sci ; 369(1): 82-90, 2012 Mar 01.
Article En | MEDLINE | ID: mdl-22226474

The synthesis and properties of thermal/pH-sensitive core-shell copolymer nano/microgels were investigated. The crosslinked core consisted of N-isopropylacrylamide (NIPAAm) while the shell was stabilized by poly(ethylene glycol) methyl ether methacrylate (PEGMA) and 2-methacryloyloxybenzoic acid (2MBA) using a "one pot" soapless emulsion polymerization method. Monodisperse particles were produced with average hydrodynamic diameters ranging from 40 to 880 nm, as determined by dynamic light scattering (DLS) in water at 25°C, depending on the synthetic recipe used. The influence of PEGMA and 2MBA content on size and temperature transition at different pH values was studied. Zeta potential measurements and acid-base titration studies demonstrated almost complete incorporation of acid comonomer (2MBA) into the nano/microgels. Two different crosslinkers, a stable and an acid labile, were compared. The crosslinker used has a major influence on the size and charge density of the nano/microgels produced. Microscopic studies confirmed the core-shell morphology of the nano/microgels.

7.
Rev. esp. patol. torac ; 23(4): 299-303, oct.-dic. 2011. ilus
Article Es | IBECS | ID: ibc-104706

Objetivo: Analizar si existe empeoramiento de síntomas otorrinolaringológicos (rinorrea, obstrucción nasal y disfonía) en (..) (AU)


Objective: To analyse if there is worsening of several otorhinolaryngological sypmtoms (..) (AU)


Humans , Female , Asthma/complications , Premenstrual Syndrome/complications , Rhinitis/epidemiology , Otorhinolaryngologic Diseases/epidemiology , Menstrual Cycle , Prospective Studies
8.
Int J Clin Pharmacol Ther ; 48(8): 525-33, 2010 Aug.
Article En | MEDLINE | ID: mdl-20650044

PURPOSE: A vancomycin population pharmacokinetic prediction model for adult and elderly patients was developed using NONMEM. The predictability of the model was studied and compared with ten other models. METHODS: Data were collected from routine care of 141 subjects. NONMEM was used to derive a population model. After internal evaluation using the bootstrap technique, external validation was studied using an independent dataset that consisted of 95 subjects; a statistical comparison of precision and bias was conducted. RESULTS: A two-compartment open model was derived with body weight, age, and CLcr as covariates. The bootstrap process showed stability of the model. A comparison of subjects older and younger than 65 years found that the older group had a mean clearance of 2.24 (+/- 1.2) l/h compared to 4.03 (+/- 1.7) l/h, and a peripheral volume of 43.7 (+/- 5.1) l compared to 28.4 (+/- 5.3) l compared to younger patients. These values were modeled using CLcr in the clearance equation and Vd as a function of age. The eleven models studied showed a bias in predicting serum concentrations from the test database that ranged from 0.35 mg/l to -5.93 mg/l. Precision ranged from 4.53 mg/l to 8.05 mg/l. Our method ranked in fourth place overall and when compared statistically its bias was different from the method that ranked in second place by -1.45 (95% CI -2.46, -0.42; p = 0.005), and different from all the methods that ranked worse. The only difference in precision was with the method that ranked in eleventh place with a relative precision of 0.49 (95% CI 0.27, 0.70; p < 0.001). CONCLUSIONS: A two-compartment open model fitted the data with weight, age, and CLcr as covariates. The derived method ranked in fourth place overall. The two-compartment nature of two of the equations studied did not provide an advantage. A future study with more data in the distribution phase could provide a model with better predictability.


Anti-Bacterial Agents/pharmacokinetics , Models, Biological , Vancomycin/pharmacokinetics , Adult , Age Factors , Aged , Bias , Body Weight , Female , Humans , Male , Middle Aged , Nonlinear Dynamics , Retrospective Studies , Tissue Distribution
9.
Biomaterials ; 22(9): 957-61, 2001 May.
Article En | MEDLINE | ID: mdl-11311014

The bioadhesive properties of the hydrophobic, basic polyelectrolyte hydrogel disks containing crosslinked N,N-dimethylaminoethyl methacrylate-co-methyl methacrylate 30/70mol% were evaluated in vitro using gastric (pH 1.2), sublingual (pH 6.5), vaginal (pH 4.0) and intestinal (pH 7.5) pig's mucosas. Adhesive strength was measured using a modified Du Noüy tensiometer by measuring the force of detachment between a gel disk and the respective mucosa. The effect of crosslinker content in the gel was evaluated. It was found an increase in the adhesive strength with the increase of crosslinker content in the pH range of 4.0-7.5. For the evaluation at pH 1.2 (gastric mucosa) the opposite behavior was observed. The results indicate that initial bioadhesive contact may be the result of surface energy effects and/or electrostatic interactions of oppositely charged groups between mucin and the gel. In some cases, mucus dehydration may also be involved. When the gel is swollen, chain interpenetration also plays a roll in the bioadhesive interaction. The gels presented bioadhesive forces in gastric and vaginal mucosas (acidic medium), similar to the adhesive forces of well-known bioadhesives such as hydroxymethylcellulose and sodium alginate to the intestinal mucosa. The results indicate that hydrophobic polybasic gels present bioadhesive properties that make them suitable for site specific, pH controlled drug delivery.


Methacrylates/pharmacology , Methylmethacrylate/pharmacology , Tissue Adhesives/pharmacology , Animals , Female , Hydrogen-Ion Concentration , In Vitro Techniques , Kinetics , Microscopy, Electron , Swine
10.
Eur J Biochem ; 268(5): 1323-31, 2001 Mar.
Article En | MEDLINE | ID: mdl-11231284

The nitrogen-fixing, symbiotic root-nodule forming bacterium Bradyrhizobium japonicum USDA 110 contained gammacerane derivatives next to triterpenoids of the hopane series. Diploptene, diplopterol, 2 beta-methyldiplopterol, aminobacteriohopanetriol and adenosylhopane were accompanied by tetrahymanol and the corresponding novel methylated homologues 2 beta-methyltetrahymanol, 20 alpha-methyltetrahymanol, and 2 beta,20 alpha-dimethyltetrahymanol. Incorporation of [(2)H(3)]methyl-L-methionine indicated that the additional methyl groups originated from methionine, probably with S-adenosylmethionine acting as methyl donor, with retention of the three deuterium atoms. The simultaneous presence of hopane and gammacerane derivatives seems a characteristic feature of the genus Bradyrhizobium and the phylogenetically closely related Rhodopseudomonas palustris.


Bradyrhizobium/chemistry , Triterpenes/metabolism , Bradyrhizobium/metabolism , Chromatography, Thin Layer , Cyclization , Deuterium/metabolism , Gas Chromatography-Mass Spectrometry , Lyases/metabolism , Magnetic Resonance Spectroscopy , Methionine/analogs & derivatives , Methionine/metabolism , Methylation , Phylogeny , Polyisoprenyl Phosphates/metabolism , Rhodopseudomonas/chemistry , Rhodopseudomonas/metabolism , S-Adenosylmethionine/metabolism , Symbiosis , Triterpenes/chemistry
11.
Planta ; 211(1): 62-71, 2000 Jun.
Article En | MEDLINE | ID: mdl-10923704

The mpi gene encodes a maize proteinase inhibitor (MPI) protein whose mRNA accumulates in response to mechanical wounding. In this study, mpi gene expression in response to different types of damage was investigated. In mechanically damaged leaves of maize (Zea mays L.), mpi mRNA accumulation was affected by the degree of damage inflicted on the leaf. Consecutive wounds resulted in higher levels of mpi transcripts. The MPI protein was expressed in Escherichia coli and purified. Polyclonal antibodies were then produced and used to study MPI accumulation in insect-wounded and mechanically wounded maize leaves. When larvae of the lepidopteran insect Spodoptera littoralis were fed on maize leaves, MPI accumulated in tissues adjacent to the wound site. The level of inhibitor accumulation was higher in leaves chewed by larvae than in leaves that had been damaged mechanically. Longer feeding periods also resulted in higher levels of MPI accumulation. Additionally, the inhibitory properties of MPI toward mammalian and insect digestive serine proteinases were determined. Contrary to the majority of the plant proteinase inhibitors described, MPI is an inhibitor of mammalian elastase that only weakly inhibits mammalian chymotrypsin. However, both elastase and chymotrypsin-like activities from the larval midgut of S. littoralis were effectively inhibited by MPI. We discuss these results with regard to the function and evolution of plant proteinase inhibitors. The availability of a plant proteinase inhibitor which is able to inhibit the two types of insect digestive proteinase, elastase and chymotrypsin, might be useful for engineering protection against lepidopteran insect pests in transgenic plants.


Protease Inhibitors/metabolism , Spodoptera/enzymology , Zea mays/enzymology , Amino Acid Sequence , Animals , Plant Leaves , Plant Proteins/genetics , Plant Proteins/metabolism , Zea mays/physiology
12.
Gastroenterol Hepatol ; 22(4): 163-6, 1999 Apr.
Article Es | MEDLINE | ID: mdl-10349784

BACKGROUND: The use of botulinic toxin has led to new perspectives in the treatment of anal fissures. However, the most effective dose, length of treatment and long term results require further studies to determine the most appropriate place for this therapy. PATIENTS AND METHODS: A prospective study was carried out in 40 consecutive patients diagnosed with anal fissure of more than 3 months in duration. Fifteen U of botulinic toxin were injected in the external anal sphincter and the evolution was studied over 6 months. The patients completed a pain scale designed for the study after 1 week, and 1, 3 and 6 months after the injection. The degree of pain, healing and need for surgery were evaluated during the follow up. RESULTS: Healing occurred in 17 patients after 3 months (42.5%) and after 6 months in 3 more patients (50%). Eight patients required surgery during follow up (20%). In the remaining patients, the pain significantly decreased allowing conservative management. Only 2 patients demonstrated incontinence for slight, transitory gases (5%). CONCLUSIONS: Injection of botulinic toxin is well tolerated and is relatively effective as an alternative in the treatment of anal fissure. Most patients respond in the first days after treatment and the effect persists for at least 6 months. The use of doses higher than those used in this study merits further studies.


Botulinum Toxins/therapeutic use , Fissure in Ano/drug therapy , Adult , Anal Canal , Chi-Square Distribution , Chronic Disease , Female , Follow-Up Studies , Humans , Injections, Intralesional , Logistic Models , Male , Middle Aged , Retrospective Studies , Time Factors
16.
FEMS Microbiol Lett ; 164(1): 169-75, 1998 Jul 01.
Article En | MEDLINE | ID: mdl-9675863

Labeling experiments using [1-13C]acetate or [1-13C]glucose were performed with opportunistic pathogenic bacteria, with innocuous bacteria related to pathogenic species or with phytopathogenic species. The labeling pattern was determined in the isoprenic moiety of ubiquinone or menaquinone derivatives. These experiments showed that Acinetobacter, Citrobacter, Erwinia, Pseudomonas, Burkholderia, Ralstonia and Mycobacterium synthesize their isoprenoids via the mevalonate-independent glyceraldehyde 3-phosphate/pyruvate route. Enzymes of this novel bacterial metabolic route, which is apparently absent in vertebrates and man, therefore represent potential targets for a novel type of antibacterial drugs.


Gram-Negative Aerobic Rods and Cocci/metabolism , Mycobacterium/metabolism , Pseudomonas/metabolism , Ubiquinone/metabolism , Vitamin K/metabolism , Acetates/metabolism , Glucose/metabolism
17.
Biomaterials ; 17(12): 1187-93, 1996 Jun.
Article En | MEDLINE | ID: mdl-8799503

Copolymers of N, N-diethylaminoethyl methacrylate (DEA) and methyl methacrylate (MMA) were synthesized in ethanolic solution and characterized in terms of reactivity ratios, densities and water vapour sorption. For the reaction conditions studied the copolymerization is essentially random. Polymer densities, determined by centrifugation in a density gradient, range from 1.10 for pDEA to 1.13 for p(DEA/MMA) 52/48 mol%. Flory-Huggins chi parameters were determined by isopiestic water vapour sorption, and were found to depend on both the comonomer ratio and the water content. An exceptionally strong dependence of chi on water content (or equivalently, polymer volume fraction) suggests that Flory-Huggins theory is not the proper theory to apply, especially for the polymers with the highest MMA content. Analysis of the data in terms of the Zimm-Lundberg cluster theory reveals that as the polymer becomes more hydrophobic and glassy with increased MMA, the sorption becomes more nonuniform in the polymer.


Methacrylates/chemistry , Methylmethacrylates/chemistry , Water/chemistry , Adsorption , Chemical Phenomena , Chemistry, Physical , Methacrylates/chemical synthesis , Methylmethacrylate , Methylmethacrylates/chemical synthesis , Thermodynamics , Volatilization
18.
Mutat Res ; 349(2): 201-8, 1996 Feb 01.
Article En | MEDLINE | ID: mdl-8600351

The role of MucAB and Escherichia coli UmuDC proteins in mutagenesis by 4-quinolone (4-Q) compared to that in UV mutagenesis has been studied in hisG428 Salmonella typhimurium strains. A low-copy plasmid carrying mucAB genes, but not umuDC, promotes reversion of the hisG428 mutation by the 4-Q ciprofloxacin. In contrast, a umuDC plasmid mediates the reversion of hisG428 by UV, although less efficiently than a mucAB one. In addition, a unique copy of mucAB genes is enough to promote UV mutagenesis, whereas, several copies of them are required to detect ciprofloxacin mutagenesis. Therefore, the mutagenic repair of quinolone damage by MucAB proteins is not a very efficient process. The presence of an umuD'C plasmid but not a mucA'B one, slightly increases the reversion of the hisG428 mutation by ciprofloxacin and this finding is further discussed. In contrast, MucA'B are still more active than UmuD'C proteins in UV mutagenesis. These results suggest that the enhanced processing of MucA compared to UmuD would not explain all functional differences between MucAB and UmuDC proteins in the error-prone DNA repair.


Anti-Infective Agents/pharmacology , Bacterial Proteins/metabolism , Ciprofloxacin/pharmacology , Escherichia coli Proteins , Escherichia coli/genetics , Mutagenesis , Mutagens/pharmacology , Salmonella typhimurium/genetics , Ultraviolet Rays , DNA-Directed DNA Polymerase , Dose-Response Relationship, Drug , Escherichia coli/metabolism , Genes, Bacterial , Kinetics , Operon , Peptide Hydrolases/metabolism , Plasmids , SOS Response, Genetics , Salmonella typhimurium/drug effects , Salmonella typhimurium/radiation effects
19.
Environ Mol Mutagen ; 27(2): 110-5, 1996.
Article En | MEDLINE | ID: mdl-8603664

The mutagenic events induced by ciprofloxacin, a potent antimicrobial agent, have been characterized. For this, a battery of His mutants of Salmonella typhimurium (hisG428, his G46, His C9070, and his G1775 targets) that detects the six possible transitions and transversions [Levin and Ames (1986): Environ Mutagen 8:9-28] and two additional His strains (hisC3076 and his D3052 targets) carrying frameshift mutations have been used. Our results indicate that GC-TA transversions are the major base-pair substitution induced by ciprofloxacin and that GC-At transitions are also produced, but to a lesser degree. However, we cannot discard the fact that At-Ta transversions are also induced. In addition, the data indicate that the mutational specificity of ciprofloxacin depends on the location of the target. Intragenic base-pair substitutions are the most frequent mutations at the hisG428 target when it is on the chromosome, whereas 3 or 6 base-pair deletions are the major mutagenic events when this target is on the plasmid pAQ1. We have shown that ciprofloxacin also induces deletions/insertions at the hisC3076 and hisD3052 frameshift targets. Therefore, this inhibitor of DNA gyrase promotes a wide pattern of mutations including different kinds of base-pair substitutions, 3 or 6 base-pair deletions, and insertions/deletions resulting in frameshifts. All of these mutagenic events require the MucAb proteins involved in the error-prone repair, with the exception of base-pair insertions/deletions at the hisD3052 target, which are independent of the presence of plasmid pKM101.


Anti-Infective Agents/toxicity , Ciprofloxacin/toxicity , Mutation/drug effects , Salmonella typhimurium/drug effects , Base Composition , DNA Damage , DNA Repair/genetics , DNA, Bacterial/antagonists & inhibitors , Frameshift Mutation/drug effects , Frameshift Mutation/genetics , Genes, Bacterial/drug effects , Genes, Bacterial/genetics , Mutagenicity Tests , Mutation/genetics , Plasmids , Salmonella typhimurium/genetics
20.
J Bacteriol ; 176(24): 7719-26, 1994 Dec.
Article En | MEDLINE | ID: mdl-8002598

The major pigment produced by Staphylococcus aureus Newman is the deep-yellow carotenoid 4,4'-diaponeurosporene; after prolonged cultivation, this pigment is in part converted to the orange end product staphyloxanthin. From this strain a 3.5-kb DNA fragment was identified which after being cloned into Escherichia coli and Staphylococcus carnosus conferred the ability to produce 4,4'-diaponeurosporene. DNA sequencing of this fragment revealed two open reading frames (ORFs) which are very likely cotranscribed. ORF1 encodes a 254-amino-acid hydrophobic protein, CrtM (M(r), 30,121). The deduced sequence of CrtM exhibits in three domains similarities to the sequences of Saccharomyces cerevisiae and human squalene synthases and phytoene synthases of various bacteria. ORF2 encodes a 448-amino-acid hydrophobic protein, CrtN, with an M(r) of 50,853 whose deduced sequence is similar to those of phytoene desaturases of other bacteria. At the N terminus of CrtN a classical FAD-, NAD(P)-binding domain is found. Spectrophotometry and gas chromatography-mass spectrometry analyses of the carotenoid production of E. coli and S. carnosus clones containing either ORF1 or both ORFs together suggest that ORF1 and ORF2 represent the dehydrosqualene synthase gene (crtM) and the dehydrosqualene desaturase gene (crtN), respectively. The results furthermore suggest that the biosynthesis of 4,4'-diaponeurosporene starts with the condensation of two molecules of farnesyl diphosphate by dehydrosqualene synthase (CrtM); it is shown that the reaction product of this enzyme is dehydrosqualene and not squalene. Dehydrosqualene (4,4'-diapophytoene) is successively dehydrogenated by a desaturase (CrtN) to form the yellow main intermediate 4,4'-diaponeurosporene.


Bacterial Proteins , Carotenoids/biosynthesis , Farnesyl-Diphosphate Farnesyltransferase/genetics , Genes, Bacterial/genetics , Oxidoreductases/genetics , Staphylococcus aureus/genetics , Amino Acid Sequence , Base Sequence , Carotenoids/isolation & purification , Escherichia coli/enzymology , Escherichia coli/genetics , Molecular Sequence Data , Restriction Mapping , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Squalene/analogs & derivatives , Squalene/isolation & purification , Squalene/metabolism , Staphylococcus/enzymology , Staphylococcus/genetics , Staphylococcus aureus/enzymology , Triterpenes
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