Correction to: A thiotrophic microbial community in an acidic brine lake in Northern Chile.

In Table 1 of the original article, the unit mg/L was incorrectly published as ng/L in the aluminum, chloride, sulphate and OM columns.

A thiotrophic microbial community in an acidic brine lake in Northern Chile.

The endorheic basins of the Northern Chilean Altiplano contain saline lakes and salt flats. Two of the salt flats, Gorbea and Ignorado, have high acidic brines. The causes of the local acidity have been attributed to the occurrence of volcanic native sulfur, the release of sulfuric acid by oxidation, and the low buffering capacity of the rocks in the area. Understanding the microbial community composition and available energy in this pristine ecosystem is relevant in determining the origin of the acidity and in supporting the rationale of conservation policies. Besides, a comparison between similar systems in Australia highlights key microbial components and specific ones associated with geological settings and environmental conditions. Sediment and water samples from the Salar de Gorbea were collected, physicochemical parameters measured and geochemical and molecular biological analyses performed. A low diversity microbial community was observed in brines and sediments dominated by Actinobacteria, Algae, Firmicutes and Proteobacteria. Most of the constituent genera have been reported to be either sulfur oxidizing microorganisms or ones having the potential for sulfur oxidation given available genomic data and information drawn from the literature on cultured relatives. In addition, a link between sulfur oxidation and carbon fixation was observed. In contrast, to acid mine drainage communities, Gorbea microbial diversity is mainly supported by chemolithoheterotrophic, facultative chemolithoautotrophic and oligotrophic sulfur oxidizing populations indicating that microbial activity should also be considered as a causative agent of local acidity.

Flavodoxin overexpression confers tolerance to oxidative stress in beneficial soil bacteria and improves survival in the presence of the herbicides paraquat and atrazine.

AIM: To determine whether expression of a cyanobacterial flavodoxin in soil bacteria of agronomic interest confers protection against the widely used herbicides paraquat and atrazine. METHODS AND RESULTS: The model bacterium Escherichia coli, the symbiotic nitrogen-fixing bacterium Ensifer meliloti and the plant growth-promoting rhizobacterium Pseudomonas fluorescens Aur6 were transformed with expression vectors containing the flavodoxin gene of Anabaena variabilis. Expression of the cyanobacterial protein was confirmed by Western blot. Bacterial tolerance to oxidative stress was tested in solid medium supplemented with hydrogen peroxide, paraquat or atrazine. In all three bacterial strains, flavodoxin expression enhanced tolerance to the oxidative stress provoked by hydrogen peroxide and by the reactive oxygen species-inducing herbicides, witnessed by the enhanced survival of the transformed bacteria in the presence of these oxidizing agents. CONCLUSIONS: Flavodoxin overexpression in beneficial soil bacteria confers tolerance to oxidative stress and improves their survival in the presence of the herbicides paraquat and atrazine. Flavodoxin could be considered as a general antioxidant resource to face oxidative challenges in different micro-organisms. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of plant growth-promoting rhizobacteria or nitrogen-fixing bacteria with enhanced tolerance to oxidative stress in contaminated soils is of significant agronomic interest. The enhanced tolerance of flavodoxin-expressing bacteria to atrazine and paraquat points to potential applications in herbicide-treated soils.

Effects of salt stress and rhizobial inoculation on growth and nitrogen fixation of three peanut cultivars.

Increasing soil salinity represents a major constraint for agriculture in arid and semi-arid lands, where mineral nitrogen (N) deficiency is also a frequent characteristic of soils. Biological N fixation by legumes may constitute a sustainable alternative to chemical fertilisation in salinity-affected areas, provided that adapted cultivars and inoculants are available. Here, the performance of three peanut cultivars nodulated with two different rhizobial strains that differ in their salt tolerance was evaluated under moderately saline water irrigation and compared with that of N-fertilised plants. Shoot weight was used as an indicator of yield. Under non-saline conditions, higher yields were obtained using N fertilisation rather than inoculation for all the varieties tested. However, under salt stress, the yield of inoculated plants became comparable to that of N-fertilised plants, with minor differences depending on the peanut cultivar and rhizobial strain. Our results indicate that N fixation might represent an economical, competitive and environmentally friendly choice with respect to mineral N fertilisation for peanut cultivation under moderate saline conditions.

Diversity of rhizobial bacteria isolated from nodules of the Gypsophyte Ononis tridentata L. growing in Spanish soils.

The aim of this work is to describe the diversity and phylogeny of rhizobial bacteria associated to nodules of Ononis tridentata L. in different geographical regions of Spain. Twenty-two bacterial isolates were characterized using several molecular techniques (16S amplified ribosomal deoxyribonucleic acid restriction analysis, fingerprinting, and sequencing) and phylogenies were inferred from their 16S and nodC gene sequences. Phylogenetically, the isolates grouped with the genera Rhizobium, Mesorhizobium, Phylobacterium, and Bosea. The nodC gene, essential for nodulation, was detected for the first time in isolates close to the genera Bosea and Phyllobacterium. The bacteria isolated showed a high diversity at the genus, species, and strain level regardless of the geographical origin of the host plant. This is the first report describing bacteria associated to nodules of O. tridentata. This shrub legume is highly prized for the revegetation of gypsum soils in semiarid Mediterranean areas. Our molecular description of bacteria associated to this legume improves the current understanding of the ecology of this plant species. Our findings have implications for formulating suitable bacterial inocula to recover gypsum ecosystems.

Transgenic Medicago truncatula plants that accumulate proline display nitrogen-fixing activity with enhanced tolerance to osmotic stress.

Legume root nodule nitrogen-fixing activity is severely affected by osmotic stress. Proline accumulation has been shown to induce tolerance to salt stress, and transgenic plants over-expressing Delta(1)-pyrroline-5-carboxylate synthetase (P5CS), which accumulates high levels of proline, display enhanced osmotolerance. Here, we transformed the model legume Medicago truncatula with the P5CS gene from Vigna aconitifolia, and nodule activity was evaluated under osmotic stress in transgenic plants that showed high proline accumulation levels. Nitrogen fixation was significantly less affected by salt treatment compared to wild-type (WT) plants. To our knowledge, this is the first time that transgenic legumes have been produced that display nitrogen-fixing activity with enhanced tolerance to osmotic stress. We studied the expression of M. truncatula proline-related endogenous genes M. truncatulaDelta(1)-pyrroline-5-carboxylate synthetase 1 (MtP5CS1), M. truncatulaDelta(1)-pyrroline-5-carboxylate synthetase 2 (MtP5CS2), M. truncatula ornithine delta-aminotransferase (MtOAT), M. truncatula proline dehydrogenase (MtProDH) and a proline transporter gene in both WT and transgenic plants. Our results indicate that proline metabolism is finely regulated in response to osmotic stress in an organ-specific manner. The transgenic model allowed us to analyse some of the biochemical and molecular mechanisms that are activated in the nodule in response to high salt conditions, and to ascertain the essential role of proline in the maintenance of nitrogen-fixing activity under osmotic stress.

Thermoluminescence response of calcic bentonite subjected to conditions of high nuclear waste underground storage.

Bentonite is regarded as a backfilling material for underground storage facilities of highly radioactive nuclear waste built on granite formations. In these facilities, bentonite will be subjected to a gradient of temperature and dose rate, achieving a very high integrated dose and, therefore, changes in its structure and physical properties may take place. Two experiments to discriminate between the thermal and the irradiation effect were performed. In the first (named BIC 2A), samples were subjected to temperature while in the second (named BIC-2B) the combined effect of temperature and irradiation was studied. The experimental conditions were: a thermal gradient between 130 degrees C and 90 degrees C, a maximum dose rate of 3.5 kGy.h(-1) and a gradient of the integrated dose between 1.75 MGy and 10 MGy. Both experiments lasted a total of 124 days. An irradiation source of 60Co with an activity close to 300,000 Ci, and bentonite samples of 200 mm in length and 50 mm in diameter were used. After the experiment, the samples were ground and two fractions were obtained: a fine fraction (<2 microm) enriched in montmorillonite clay mineral and a coarse fraction (>80 microm). The results are described of thermoluminescence analyses on the two fractions obtained which showed that the coarse fraction can be 100 times more sensitive to radiation than the fine fraction. On the other hand, the heated and irradiated samples showed a thermoluminescence response around 50 times greater than the samples that were only heated. In addition to this, the temperature and dose rate conditions are relevant parameters in the generation and stabilisation of radiation induced defects. Finally, the response of samples heated and irradiated for two months was quite similar to that obtained on samples heated and irradiated for four months, indicating a saturation phenomenon.

[Long-term course of laryngeal verrucous carcinoma]. / Carcinoma verrucoso laríngeo de larga evolución.

Verrucous carcinoma is an odd kind from squamous or epidermoid carcinoma, amounting between 1 and 3.5% percent of the whole number of laryngeal growths. Its predominant sitting is glottic and are characterized through the pathological anatomy and its good prognosis. We report one case treated in our Department which evolved during 14 years and we point out its good prognosis and other particularities regarding its etiology, pathologic anatomy and diagnosis.

[Sarcoidosis in otorhinolaryngology]. / Sarcoidosis en O.R.L.

Sarcoidosis is a disease affecting the reticulo-histiocytary system and characterized by its several manifestations, always linked to the same lesion: the epithelioid granuloma without caseous necrosis. We make a review of this disease so scarce in our consulting rooms, and consider all patients diagnosed in our Hospital during one year-term, with their manifestations in ENT-area as well in other specialties and compare our inventory with other published series.

[Sjögren syndrome in ORL. Diagnostic considerations]. / Síndrome de Sjögren en O.R.L. Consideraciones diagnósticas.

A presentation the history of a 51-year-old woman with xerostomia and keratoconjunctivitis sicca (KCS), developed in 10 months, investigations revealed the presence in serum of antibodies against cytoplasmic antigens SS-A (Ac anti-Ro/SS-A), antinuclear antibodies (ANAs) and rheumatoid factor (RF). The Rose Bengal test was positive and in the salivary gammagraphy, made with pertecnate 99 mTc, it was observed a decrease of the captation and excretion of the designer for salivary glands. The histopathology and immunohistochemical study of minor salivary glands showed the presence of a focal lymphocitic sialadenitis (fsa) and a predominance of lymphocites CD4+. It was diagnosed as primary Sjögren's syndrome (PSS) and the patient treated with salivary substitutes, artificial tears and corticoids. We analyse the current diagnostic criteria of the group of study of the European Community for the Sjögren's syndrome (SS) and emphasize the importance of histologic and immunochemical studies, that together with the rest of complementary tests will led us to distinguish not only the different forms of the presentation of the illness but also those of all patients with pathologies which are nowadays very prevalent in our environment, such as the hepatitis C (HCV) an the human immune deficiency (HIV) virus infections.

[Jugular-tympanic paraganglioma: our experience in 2 years]. / Paraganglioma yugulotimpánico: nuestra experiencia en dos años.

The paper is a review of the jugulotympanic paragangliomata seen in our Hospital in a 2 years term. The AA. discuss every case and achieve a checking of several therapeutics procedures accepted for these growths.

[Deep neck infections: complications of acute pharyngitis]. / Infección cervical profunda: complicación de faringitis aguda.

Deep neck infections develop as aftermath of spreading infections from an initial focus to the neighbourhood and soft tissues of the neck, through routes offering lesser resistance as fascial sheets. These cervical pictures are not numerous and generally after infective focus bad treated, linked with concomitant factors easing the rapid spread. The presence of complications as the involvement of great blood vessels, mediastin or jeopardizing the air-way may darken the prognosis, for which reason its precocious diagnosis and correct behaviour are very decisive. The paper deals with one case of neck infect, following an acute banal pharyngitis without predisposing circumstances. Follows a review of the published bibliography.

[Biopsy cannula as diagnostic alternative to puncture-aspiration biopsy with fine needle in head and neck tumors]. / La cánula de biopsia: alternativa diagnóstica de la punción-aspiración con aguja fina en tumores de cabeza y cuello.

Biopsy cannula is a diagnostic tool allowing anatomopathological examination of tissue samples, achieved through a percutaneous perforation. Unlike puncture-aspiration with fine needle method that only permits a cytologic study, this technique eases the removal of pieces big enough to provide the knowledge of the whole architecture of the lesion. At length in other specialities in our has been forgotten perhaps for the great efficiency of PAFN on neck masses or as complement of traditional surgery. We present one case in which the biopsy-cannula showed its diagnostic usefulness. We also discuss on the technique and made a bibliographic perusal about the published literature.

[Cervical emphysema caused by Forestier's disease]. / Enfisema cervical por enfermedad de forestier.

Diffuse idiopathic skeletal hyperostosis is a rare cause of dysphagia, preferentially affecting older men. This condition is also known as Forestier's malady, being characterized by a paravertebral ossification of 4 contiguous vertebrae at least. Seldom is the last etiology evoked for high dysphagia after other possible diagnosis exclusion. The diagnosis is confirmed by standard or contrast radiography. Introductory treatment is medical, being the surgery indicated for serious or resisting cases. One case is reported with dysphagia as primary sign of Forestier's malady, and review of possible diagnostic exams and treatments.

[Neurinoma of the cervical hypoglossal nerve. A clinical case and review of the literature]. / Neurinoma del hipogloso cervical. Caso clínico y revisión de literatura.

Neurilemmomas are relatively rare tumors derived from Schwann cells that may occur at any part of the body. Many are encapsulated and they are more frequently encountered in adults. A neurilemmoma of the hypoglossal cervical nerve, an unusual site, is reported. Submaxillary angioma was initially suspected.

[Neuroendocrine tumor of the submandibular gland. Report of one case and review of literature]. / Tumor neuroendocrino de glándula submaxilar. Presentación de un caso y revisión de literatura.

Report on one case of primary neuroendocrine tumor of the submandibularis gland, early detected without initial spread. Immunohistochemistry and electron microscopy were realized in order to determine the presence of intracytoplasmatic hypersecretory thick granules, these being the laboratory trials to differentiate between neuroendocrine tumors and undifferentiate carcinomata. Bibliographic review and proposal of classification of this sort of tumors.

[Granular cell tumor of the larynx]. / Tumor de células granulomatosas de laringe.

Granular cell tumor is an unusual growth of probably neuroectodermal histogenesis, first reported by Abrikossoff in 1926 with the name of myoblastoma. Of the about 1200 cases reported since, the 50 percent were found in the head and neck. Of second mentioned 10 percent had a laryngeal sitting. A case of glottic granular cell tumor surgically removed with free borders is presented. Bibliographical review.

[Vernet's syndrome as an early manifestation of systemic erythematous lupus]. / Síndrome de Vernet como manifestación precoz de un lupus eritematoso sistemico.

Report of one case of Vernet's syndrome (involving the IX, X and XIth cranial nerves) in a young woman, as early sing of SEL. The patient presented the 4 criteria suggested by the American Society in order to diagnose SEL: arthritis, serositis, positive anti-nuclear antibodies and anemia. The AA. carry out a study in search of other cases sitting in the larynx and a perusal about etiopathogenical theories as well. Hinting, for the clinical picture, of being it due to a localised vasculitis of vasa nervorum, a treatment with corticoids and pentoxifylline was ordered, being the outcome, after 3 weeks, the eradication of ENT syndrome.

Induced new mutation of D1 serine-268 in soybean photosynthetic cell cultures produced atrazine resistance, increased stability of S2QB- and S3QB- states, and increased sensitivity to light stress.

We have isolated several herbicide-resistant cell lines from photosynthetic cell suspensions of soybean (Glycine max) that possessed different levels of herbicide resistance, photosystem II activity, and chlorophyll a/b ratio. We have further studied the STR7 mutant, which showed the highest level of resistance to atrazine as well as a cross-resistance to 3-(3,4-dichlorophenyl)-1, 1-dimethylurea (50- and 3-fold, respectively, compared with the wild type). Sequencing of the psbA gene (coding for the D1 polypeptide of photosystem II) from this mutant revealed a single change, serine-268 to proline, in the D1 protein. To our knowledge, this substitution has not previously been described in any photosynthetic organism. In addition to affecting atrazine resistance, this single amino acid change caused a decrease in the electron transfer rate between the secondary acceptors QA and QB and a stabilization of the S2QB- and S3QB- states. The mutant also showed a larger antenna size, an increase in non-QB-reducing centers, and a higher sensitivity to light stress. The unusual stability of the S2QB- and S3QB- states indicates that STR7 belongs to a new class of QB-site mutants.

Photoinhibition of photosystem II from higher plants. Effect of copper inhibition.

Strong illumination of Cu(II)-inhibited photosystem II membranes resulted in a faster loss of oxygen evolution activity compared with that of the intact samples. The phenomenon was oxygen- and temperature-dependent. However, D1 protein degradation rate was similar in both preparations and slower than that found in non-oxygen evolving PSII particles (i.e. Mn-depleted photosystem II). These results seem to indicate that during illumination Cu(II)-inhibited samples do not behave as a typical non-oxygen evolving photosystem II. Cytochrome b559 was functional in the presence of Cu(II). The effect of Cu(II) inhibition decreased the amount of photoreduced cytochrome b559 and slowed down the rate of its photoreduction. The presence of Cu(II) during illumination seems to protect P680 against photodamage as occurs in photosystem II reaction centers when the acceptor side is protected. The data were consistent with the finding that production of singlet oxygen was highly reduced in the preparations treated with Cu(II). EPR spin trapping experiments showed that inactivation of Cu(II)-treated samples was dominated by hydroxyl radical, and the loss of oxygen evolution activity was diminished by the presence of superoxide dismutase and catalase. These results indicate that the rapid loss of oxygen evolution activity in the presence of Cu(II) is mainly due to the formation of .OH radicals from superoxide ion via a Cu(II)-catalyzed Haber-Weiss mechanism. Considering that this inactivation process was oxygen-dependent, we propose that the formation of superoxide occurs in the acceptor side of photosystem II by interaction of molecular oxygen with reduced electron acceptor species, and thus, the primarily Cu(II)-inhibitory site in photosystem II is on the acceptor side.