Toward the development of sensors for lung cancer: The adsorption of 1-propanol on hydrophobic zeolites.

A healthy breath is mainly composed of water, carbon dioxide, molecular nitrogen, and oxygen and it contains many species, in small quantities, which are related to the ambient atmosphere and the metabolism. The breath of a person affected by lung cancer presents a concentration of 1-propanol higher than usual. In this context, the development of specific sensors to detect 1-propanol from breath is of high interest. The amount of propanol usually detected on the breath is of few ppb; this small quantity is a handicap for a reliable diagnostic. This limitation can be overcome if the sensor is equipped with a pre-concentrator. Our studies aim to provide an efficient material playing this role. This will contribute to the development of reliable and easy to use lung cancer detectors. For this, we investigate the properties of a few hydrophobic porous materials (chabazite, silicalite-1, and dealuminated faujasite). Hydrophobic structures are used to avoid saturation of materials by the water present in the exhaled breath. Our experimental and simulation results suggest that silicalite -1 (MFI) is the most suitable structure to be used as a pre-concentrator.

Characterization of adsorbed water in MIL-53(Al) by FTIR spectroscopy and ab-initio calculations.

Here, we report ab-initio calculations developed with a twofold purpose: understand how adsorbed water molecules alter the infrared spectrum of the metal-organic framework MIL-53(Al) and to investigate which are the associated physico-chemical processes. The analyzed structures are the two anhydrous narrow (np⊘) and large (lp⊘) pore forms and the hydrated narrow pore form (np-H2O) of the MIL-53(Al). For these structures, we determined their corresponding infrared spectra (FTIR) and we identified the vibrational modes associated to the dominant spectral lines. We show that wagging and scissoring modes of CO2 give flexibility to the structure for facilitating the lp⊘- np⊘ transition. In our studies, this transition is identified by eight vibrational modes including the δCH(18a) vibrational mode currently used to identify the mentioned transition. We report an exhaustive band identification of the infrared spectra associated to the analyzed structures. Moreover, the FTIR for the np-H2O structure allowed us to identify four types of water molecules linked to the host structure by one to three hydrogen bonds.

Evaluation and characterization of forage Sorghum as feedstock for fermentable sugar production.

Sorghum is a tropical grass grown primarily in semiarid and drier parts of the world, especially areas too dry for corn. Sorghum production also leaves about 58 million tons of by-products composed mainly of cellulose, hemicellulose, and lignin. The low lignin content of some forage sorghums such as brown midrib makes them more digestible for ethanol production. Successful use of biomass for biofuel production depends on not only pretreatment methods and efficient processing conditions but also physical and chemical properties of the biomass. In this study, four varieties of forage sorghum (stems and leaves) were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy and X-ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and the enzymatic hydrolysis process. Forage sorghums with a low syringyl/guaiacyl ratio in their lignin structure were easy to hydrolyze after pretreatment despite the initial lignin content. Enzymatic hydrolysis was also more effective for forage sorghums with a low crystallinity index and easily transformed crystalline cellulose to amorphous cellulose, despite initial cellulose content. Up to 72% hexose yield and 94% pentose yield were obtained using modified steam explosion with 2% sulfuric acid at 140 degrees C for 30 min and enzymatic hydrolysis with cellulase (15 filter per unit (FPU)/g cellulose) and beta-glucosidase (50 cellobiose units (CBU)/g cellulose).

Carbon dioxide degassing by advective flow from Usu volcano, Japan.

Magmatic carbon dioxide (CO2) degassing has been documented before the 31 March 2000 eruption of Usu volcano, Hokkaido, Japan. Six months before the eruption, an increase in CO2 flux was detected on the summit caldera, from 120 (September 1998) to 340 metric tons per day (September 1999), followed by a sudden decrease to 39 metric tons per day in June 2000, 3 months after the eruption. The change in CO2 flux and seismic observations suggests that before the eruption, advective processes controlled gas migration toward the surface. The decrease in flux after the eruption at the summit caldera could be due to a rapid release of CO2 during the eruption from ascending dacitic dikes spreading away from the magma chamber beneath the caldera.

Role of the ruvB gene in homologous and homeologous recombination in Rhizobium etli.

The Rhizobium etli ruvA and ruvB genes were cloned through a PCR-based approach, using degenerate primers matching conserved sectors in the amino acid sequences of RuvB from eight bacterial species. Comparative analysis of the predicted polypeptides for RuvA and RuvB of R. etli showed highly conserved blocks with the corresponding homologs in other bacteria; RuvB depicts characteristic motifs for DNA helicases (ATP-binding and DEXH-box motifs). An R. etli ruvB::loxP Sp mutant was constructed by interposon mutagenesis. This mutant was highly sensitive to DNA-damaging agents, such as methyl methanesulfonate and nitrofurantoin, implying a deficiency in DNA repair. Homologous and homeologous conjugational recombination was reduced almost tenfold in the ruvB::loxP Sp mutant; a recombination defect was also observed in assays employing recombination between small plasmids, albeit at a smaller magnitude. Although the ruvA and ruvB genes are contiguous in R. etli, complementation studies suggest that they are expressed independently.

[Distribution of the A(TA)7TAA genotype associated with Gilbert syndrome in the Spanish population]. / Distribución del genotipo A(TA)7TAA asociado al síndrome de Gilbert en la población española.

BACKGROUND: We have examined the variation in the promoter region in the gene encoding UGT-1, associated with Gilbert's syndrome, in Spanish population. PATIENTS AND METHOD: Blood DNA was obtained from 100 blood donors. Polymerase chain reaction (PCR) was used to examine the A(TA)nTAA motif in the promoter region of the UGT-1 gene. RESULTS: The frequency of the abnormal 7/7 genotype in Spanish population was 9%. The heterozygous 6/7 genotype was identified in 51% of the subjects. CONCLUSIONS: The frequency of the abnormal allele, similar in different caucasian populations, raise the question whether it would be worthwhile and cost-effective to introduce molecular screening for Gilbert's syndrome in the study of mild, chronic unconjugated hyperbilirubinemia, in the absence of haemolysis or evidence of hepatic injury.

Control of AlgU, a member of the sigma E-like family of stress sigma factors, by the negative regulators MucA and MucB and Pseudomonas aeruginosa conversion to mucoidy in cystic fibrosis.

The alternative sigma factor AlgU (Pseudomonas aeruginosa sigma E) is required for full resistance of P. aeruginosa to oxidative stress and extreme temperatures. AlgU also controls conversion of P. aeruginosa to the mucoid, alginate-overproducing phenotype associated with lethal infections in cystic fibrosis patients. Mutations that cause conversion to mucoidy in cystic fibrosis isolates occur frequently in mucA, the second gene within the algU mucABCD gene cluster. Here we analyze the biochemical basis of conversion to mucoidy. MucA was shown to act as an anti-sigma factor by binding to AlgU and inhibiting its activity. MucB, another negative regulator of AlgU, was localized in the periplasm. MucB exerts its function from this compartment, since deletion of the leader peptide and the cytoplasmic location of MucB abrogated its ability to inhibit mucoidy. These data support a model in which a multicomponent system, encompassing an anti-delta factor and elements in the periplasmic compartment, modulates activity of AlgU. Since factors controlling AlgU are conserved in other gram-negative bacteria, the processes controlling conversion to mucoidy in P. aeruginosa may be applicable to the regulation of AlgU (sigma E) equivalents in other organisms.

Characterization of the genes coding for the putative sigma factor AlgU and its regulators MucA, MucB, MucC, and MucD in Azotobacter vinelandii and evaluation of their roles in alginate biosynthesis.

The study of the biosynthesis of alginate, the exopolysaccharide produced by Azotobacter vinelandii and Pseudomonas aeruginosa, has biotechnological and medical significance. We report here the identification of the A. vinelandii genes coding for the putative sigma factor AlgU and its negative regulators MucA and MucB through the suppression of the highly mucoid phenotype of an A. vinelandii strain by a plasmid encoding MucA and MucB. The sequences of the A. vinelandii algU, mucA, and mucB genes are highly homologous to those of the corresponding P. aeruginosa genes, AlgU shows 93% identity, and MucA and MucB are 64.4 and 63.9% identical, respectively. Forming part of the same operon as algU, mucA, and mucB, two additional genes (mucC and mucD) were identified and sequenced; the product of the former gene is homologous to ORF4 of Photobacterium sp. strain SS9, and that of the latter gene belongs to the HtrA serine protease family. Interestingly, the nonmucoid A. vinelandii UW136 had a 0.9-kb insertion within the algU gene. A strong correlation between AlgU activity and alginate production by A. vinelandii was also found, as reflected in the level of algD transcription.

Characterization of the gene coding for GDP-mannose dehydrogenase (algD) from Azotobacter vinelandii.

Azotobacter vinelandii presents a differentiation process leading to the formation of desiccation-resistant cysts. Alginate, the exopolysaccharide produced by this bacterium, has been postulated to have a role in cyst formation. Here, we report the cloning and characterization of the A. vinelandii gene coding for the enzyme GDP-mannose dehydrogenase (algD), which is the key enzyme for alginate synthesis in Pseudomonas aeruginosa. This gene has a high degree of similarity with the algD gene from P. aeruginosa, and similar proteins seem to be involved in algD regulation in both bacteria. We show the existence of two mRNA start sites; one of these sites corresponds to a promoter transcribed by RNA polymerase containing a sigma E subunit. An A. vinelandii algD mutant which is completely impaired in alginate production and which is unable to form desiccation-resistant cells was constructed. The effects of NH4, NO3, and NaCl concentrations on algD transcription for three A. vinelandii strains producing different alginate levels were evaluated. We found a strict correlation between alginate production and algD transcription for the three strains studied; however, the effects on algD transcription under the conditions studied were different for each strain. The nitrogen source regulates algD expression in the wild-type strain.

Biochemical characterization and posttranslational modification of AlgU, a regulator of stress response in Pseudomonas aeruginosa.

AlgU is homologous to the extreme heat shock sigma factor sigma E from enteric bacteria. In this work, AlgU was overproduced and purified and its function investigated at the biochemical level. AlgU was shown to associate with RNA polymerase and direct transcription of a target promoter. AlgU also exhibited multiple isoforms detected by 2D gel analysis. Treatment with a Ser/Thr phosphatase shifted the distribution of isoforms towards the basic side on 2D gels, suggesting that posttranslational modifications of AlgU may involve phosphorylation. The underphosphorylated forms of AlgU copurified with RNA polymerase. It is possible that phosphorylation affects AlgU activity or its stability.

[A descriptive clinical study of a type of arthritis in beekeepers of the Badajoz area of La Siberia Extremeña]. / Estudio clínico descriptivo de un tipo de artritis en apicultores de la comarca pacense de la Siberia Extremeña.

BACKGROUND: The appearance of episodes of arthritis has been detected in beekeepers in the Siberia Extremadura (Spain) related to working with the hives. This present work describes the clinical features of such arthritic syndrome. METHODS: Sixty cases were selected at random from a previous epidemiological study to undergo a clinical protocol that included, anamnesis, physical signs, haematological, biochemical and immunological analyses, and radiological exploration of hands, wrists, feet, and pelvis. RESULTS: The picture is characterized by episodes of oligoarthritis associated with bee-stings in the affected joints or nearby. The most frequent radiologic lesions are pinched articular lines, sclerosis, and the presence of geodes. Analytically, there was frequent eosinophilia, abnormalities in haemostasis tests, and a rise in serum alkaline phosphatase. CONCLUSIONS: An acute inflammatory oligoarthritis of unknown cause has been described which affects the hands asymmetrically, and which is found in beekeepers in relation to their work with the hives. It occasionally involves into a chronic localized arthropathy capable of provoking ankylosis and permanent articular disability.

Genetic stability and xanthan gum production in Xanthomonas campestris pv. campestris NRRL B1459.

A transposon (Tn5-SC) was constructed that can be used to quantify genetic deletions or amplifications. This transposon was used to evaluate the genomic stability of Xanthomonas campestris pv. campestris NRRL B1459 and we found that the genome of this bacterium is as stable as other Gram-negative bacteria or even more stable. Homologous recombination between plasmid sequences was determined in strain NRRL B1459 and was found to occur at a similar level to that reported for other Gram-negative bacteria. We report here that in X.c.c. NRRL B1459 there is no straightforward correlation between the occurrence of genetic rearrangements and frequency of homologous recombination. These data are discussed with respect to the reported instability of strain NRRL B1459 for xanthan gum production.

Molecular cloning and characterization of the recA gene of Rhizobium phaseoli and construction of recA mutants.

The Rhizobium phaseoli recA gene has been cloned by interspecific complementation of the Fec phenotype of bacteriophage lambda. The cloned gene restored the recombination proficiency and conferred resistance to DNA-damaging agents (methyl methanesulfonate and nitrofurantoin) to an Escherichia coli recA mutant. The direction of transcription and the localization of the recA gene were determined by mutagenesis with phage MudIIPR13 and heterologous hybridization with an E. coli recA probe. An R. phaseoli recA::Spcr mutation was introduced in two R. phaseoli strains by homogenotization. The R. phaseoli recA mutants were more sensitive to DNA-damaging agents and exhibited a 100-fold reduction in recombination frequency as compared with their parental strains. A deletion of the symbiotic plasmid abolishing nodulation was found at high frequency (10(-2)) in R. phaseoli CNF42. This event was recA dependent. In R. phaseoli CFN285, two events of symbiotic instability were found at high frequency (10(-3]: one was a deletion in the symbiotic plasmid, and the other was the loss of whole symbiotic plasmid. In the CFN285 recA::Spcr mutant, only the loss of the symbiotic plasmid was observed.

Neuroleptic malignant syndrome treated with subcutaneous lisuride infusion.

A schizophrenic patient developed a characteristic clinical picture of neuroleptic malignant syndrome (NMS) while admitted to the hospital during an exacerbation of his psychiatric symptoms. Oral treatment of the NMS with bromocriptine (7.5 mg/day) or levodopa/carbidopa (125/12.5 mg) provoked intense vomiting in spite of domperidone (60 mg/day), which led to their discontinuation. In view of the deterioration of the symptoms, treatment was begun with lisuride (1-2 mg/24 h) subcutaneously. An obvious improvement was shown in 24 h, but levodopa/carbidopa (125/12.5 mg t.d.s. orally) had to be added later to achieve complete resolution of the NMS. During the recovery phase, while being treated with subcutaneous lisuride infusion and levodopa (p.o.), the patient presented with confusion, agitation, and hallucination. Lisuride infusion was stopped and levodopa was continued until complete resolution of the NMS. This case indicates that parenteral administration of lisuride or other dopamine agents such as levodopa (i.v.) or apomorphine (s.c.) may be considered an effective and practical way of treating NMS, particularly when the patient's condition makes it difficult or impossible to use other dopaminergic drugs by the oral route.

Molecular rearrangements between two plasmids of the FII incompatibility group in different recombination--deficient Escherichia coli strains.

The frequencies and types of plasmid molecular rearrangements generated in different recombinant mutants which carried two plasmids of the FII incompatibility group were studied. The wild-type cells generated molecular rearrangements mainly by interplasmidic recombination with a frequency of 2.4 x 10(-6) per cell per cell doubling. Cells in which RecF was the principal recombination pathway generated different types of molecular rearrangements that involved either both plasmids or one of the plasmids and the chromosome. The frequencies of molecular rearrangements for these cells were 50-fold greater than those of wild-type cells. The recA- cells, even when the RecE pathway was derepressed, generated rearrangements only between one of the plasmids and the chromosome, at very low frequencies (10(-9]. In wild-type cells and in RecF cells, interplasmidic recombination generated mainly cointegrates carrying DNA deletions. These cointegrates were stable in recA- or recA- RecE+ cells, but unstable in wild-type or RecF+ cells. In the latter, the cointegrates generated smaller plasmids with different molecular structures at relatively low frequencies.

Frequency of four classes of tetracycline resistance determinants in Salmonella and Shigella spp. clinical isolates.

The frequencies of tetracycline resistance determinants of the classes A, B, C, and D were determined in 53 non-lactose-fermenting clinical isolates. The most frequent class of determinant in Salmonella typhimurium and Shigella flexneri strains was class B; however, the predominant determinant in Shigella sonnei strains was class C.