Glucose uptake and its effect on gene expression in prochlorococcus.

The marine cyanobacteria Prochlorococcus have been considered photoautotrophic microorganisms, although the utilization of exogenous sugars has never been specifically addressed in them. We studied glucose uptake in different high irradiance- and low irradiance-adapted Prochlorococcus strains, as well as the effect of glucose addition on the expression of several glucose-related genes. Glucose uptake was measured by adding radiolabelled glucose to Prochlorococcus cultures, followed by flow cytometry coupled with cell sorting in order to separate Prochlorococcus cells from bacterial contaminants.

LexA-binding sequences in Gram-positive and cyanobacteria are closely related.

The lexA gene of the cyanobacterium Anabaena sp. strain PCC7120 has been cloned by PCR amplification with primers designed after TBLASTN analysis of its genome sequence using the Escherichia coli LexA sequence as a probe. After over-expression in E.

Ferredoxin-dependent iron-sulfur flavoprotein glutamate synthase (GlsF) from the Cyanobacterium synechocystis sp. PCC 6803: expression and assembly in Escherichia coli.

The unicellular cyanobacterium Synechocystis sp. PCC 6803 contains two different glutamate synthases whose genes, gltB and glsF (previously known as gltS), have been cloned (F. Navarro et al.

Aerobiological study of Chenopodiaceae and Amaranthaceae in the Mediterranean area of southwestern Spain.

The study area is characterized by a maritime Mediterranean climate, abundant presence of Chenopodiaceae in the vegetation, and a high incidence of pollinosis caused by the pollen of this family. A Hirst-type sampler was used to determine pollen concentrations in the air of the city of Huelva during 3 consecutive years (1995-1997). The total annual amount of Chenopodiaceae-Amaranthaceae pollen was between 10.

The presence of glutamate dehydrogenase is a selective advantage for the Cyanobacterium synechocystis sp. strain PCC 6803 under nonexponential growth conditions.

The unicellular cyanobacterium Synechocystis sp. strain PCC 6803 has two putative pathways for ammonium assimilation: the glutamine synthetase-glutamate synthase cycle, which is the main one and is finely regulated by the nitrogen source; and a high NADP-dependent glutamate dehydrogenase activity (NADP-GDH) whose contribution to glutamate synthesis is uncertain. To investigate the role of the latter, we used two engineered mutants, one lacking and another overproducing NADP-GDH.

Daily variation patterns of airborne allergenic pollen in southwestern Spain.

The study was carried out using a Burkard sampler installed on the roof terrace of the School of Pharmacy, Seville, for two years (1995 and 1996). Eight pollen types described in the literature as having allergenic activity were chosen. They were Poaceae, Olea europaea, Chenopodiaceae/Amaranthaceae, Plantago, Rumex, Urticaceae (including Parietaria), Cupressaceae, and Platanus hispanica.

Airborne grass (Poaceae) pollen in southern Spain. Results of a 10-year study (1987-96).

This work reports an exhaustive study of the aerobiology of the Gramineae in Seville, Spain, which is typical of coastal Mediterranean areas. Sampling was done with a Cour trap installed on the roof terrace of the School of Pharmacy, Seville, from 1987 to 1996, both inclusive. The climatic pattern of that period was characterized by two exceptionally wet years (1989 and 1996), between which were 5 consecutive years of drought (1990-5).

Olea europaea airborne pollen in southern Spain.

Background: Olea europaea pollen is one of the most abundant constituent pollens in Seville (southern Spain). It is responsible for many documented cases of pollinosis in the area.

Objective: To contribute to the useful knowledge of Olea europaea for allergists.

The NADP-glutamate dehydrogenase of the cyanobacterium Synechocystis 6803: cloning, transcriptional analysis and disruption of the gdhA gene.

The gdhA gene of Synechocystis PCC 6803, which encodes an NADP-dependent glutamate dehydrogenase (NADP-GDH), has been cloned by complementation of an Escherichia coli glutamate auxotroph. This gene was found to code for a polypeptide of 428 amino acid residues, whose sequence shows high identity with those of archaebacteria (42-47%), some Gram-positive bacteria (40-44%) and mammals (37%). The minimal fragment of Synechocystis DNA required for complementation (2kb) carries the gdhA gene preceded by an open reading frame (ORF2) encoding a polypeptide of 130 amino acids.

Existence of two ferredoxin-glutamate synthases in the cyanobacterium Synechocystis sp. PCC 6803. Isolation and insertional inactivation of gltB and gltS genes.

The first two genes of ferredoxin-dependent glutamate synthase (Fd-GOGAT) from a prokaryotic organism, the cyanobacterium Synechocystis sp. PCC 6803, were cloned in Escherichia coli. Partial sequencing of the cloned genomic DNA, of the 6.

Latitudinal study of allergenic pollen in two Spanish cities.

A comparative study was performed on the pollen spectra in 1990 in two Spanish cities with different vegetation and climate, one situated on the south coast (Huelva) and the other in the north and inland (Palencia). The flowering of Alnus and Fraxinus occurred earlier in the north, while that of grasses (Plantago, Poaceae and Urticaceae) occurred earlier and lasted longer in the south, with milder temperature conditions resulting in no fall in pollen content between winter and spring. The absence of olive pollen in Palencia reaffirms that the pollen spectrum of a locality is a consequence of the surrounding vegetation.

Effect of Glucose Utilization on Nitrite Excretion by the Unicellular Cyanobacterium Synechocystis sp. Strain PCC 6803.

Up to 1 mM nitrite was excreted by Synechocystis strain 6803 cells growing under mixotrophic or photoheterotrophic conditions. This excretion is not due to a lower ratio of nitrite and nitrate reductase activities in the presence of glucose but seems to be related to a shortage of reduced ferredoxin, their electron donor, as a result of a decrease in noncyclic photosynthetic flow observed under these circumstances. Because about 60% of the reduced nitrate is excreted, the potential utilization of cyanobacteria for removal of nitrate from contaminated waters containing high concentrations of organic compounds is questioned.

Pollen calendar of Seville and its relation to allergies.

We have carried out a study on the annual and weekly variation of airborne pollen in the air of Seville (Andalusia, Southern Spain) during 3 consecutive years using two Cour's collectors. We provide the pollen calendar of this city, which shows the annual distribution of the most important pollen types. Our results led us to check the validity of the pollen extracts usually used at the hospitals of the city to diagnose pollinosis.

A study of the aeromycoflora of Cádiz: relationship to anthropogenic activity.

We describe a quantitative and qualitative study of the fungal spores found in the air of Cádiz during 1989 using a Cour-type trap. The results of this study can be extrapolated to other coastal cities of southern Europe with a Mediterranean climate. The spores identified have been classified into 25 taxonomic categories.

Purification and characterization of the ferredoxin-glutamate synthase from the unicellular cyanobacterium Synechococcus sp. PCC 6301.

Ferredoxin-glutamate synthase from the unicellular cyanobacterium Synechococcus sp. PCC 6301 has been purified using, as main steps, ethanol fractionation in the presence of high ionic strength, ion-exchange chromatography and ferredoxin-Sepharose affinity chromatography. The overall process yielded an homogeneous enzyme with a specific activity of 30 U/mg protein, after a purification of 2800-fold with a recovery of 43%.

Light-mediated regulation of glutamine synthetase activity in the unicellular cyanobacterium Synechococcus sp. PCC 6301.

Glutamine synthetase (GS; EC 6.3.1.

[Exposure of the facial recess through the ear canal. Value in posterosuperior retraction pockets (initial results)].

19 patients had surgery for progressive [17] and/or symptomatic [2] posterior attic retraction pockets involving the facial recess. Exposition of the suprapyramidal region was obtained after endaural incision by thinning the posterior wall of the ear canal and removing the posterior-superior portion of the tympanic sulcus. This technique is less complicated than intact canal wall tympanoplasty with mastoidectomy.

In vitro reactivation of in vivo ammonium-inactivated glutamine synthetase from Synechocystis sp. PCC 6803.

Glutamine synthetase from Synechocystis sp. strain PCC 6803 is inactivated by ammonium addition to cells growing with nitrate as the nitrogen source. The enzyme can be reactivated in vitro by different methods such as alkaline phosphatase treatment, but not phosphodiesterase, by raising the pH of the crude extract to values higher than 8, by increasing the ionic strength of the cell-free extract, or by preincubation with organic solvents, such as 2-propanol and ethanol.

An NAD-specific glutamate dehydrogenase from cyanobacteria. Identification and properties.

The unicellular cyanobacterium Synechocystis sp. PCC 6803 presents a hexameric NAD-specific glutamate dehydrogenase with a molecular mass of 295 kDa. The enzyme differs from the NADP-glutamate dehydrogenase found in the same strain and is coded by a different gene.

Regulation of glutamine synthetase activity in the unicellular cyanobacterium Synechocystis sp. strain PCC 6803 by the nitrogen source: effect of ammonium.

Glutamine synthetase activity from Synechocystis sp. strain PCC 6803 is regulated as a function of the nitrogen source available in the medium. Addition of 0.

[Role of emergency subtotal colectomy in neoplastic obstructions of the left colon].

From 1984 to 1990, 60 patients underwent emergent surgery for a neoplastic obstruction of the left colon. We performed 19 colostomies without initial exeresis and 41 immediate tumoral resections. In the latter group, five subtotal colectomies (S.

Purification and properties of glutamine synthetases from the cyanobacteria Synechocystis sp. strain PCC 6803 and Calothrix sp. strain PCC 7601.

Glutamine synthetases (GSs) from two cyanobacteria, one unicellular (Synechocystis sp. strain PCC 6803) and the other filamentous (Calothrix sp. strain PCC 7601 [Fremyella diplosiphon]), were purified to homogeneity.

Ammonia assimilating enzymes from cyanobacteria: in situ and in vitro assay using high-performance liquid chromatography.

Assay systems for ammonia assimilating enzymes in cyanobacteria are reported. Glutamine synthetase, glutamate synthase, and glutamate dehydrogenase can be easily assayed in situ, after the cells are made permeable to the reagents, or in vitro. The method is based upon the quantitation of glutamine or glutamate after the separation, when needed, of their o-phthaldialdehyde derivatives by reverse-phase high-performance liquid chromatography on a C18 column.

[Cholesteatoma of the ear].

Cholesteatoma of the ear is characterized by the presence of a keratinizing squamous epithelium in the cavities of the middle ear. The epithelium invades the ear either by direct migration or by retraction of the eardrum. Owing to is potentials for migration, desquamation, bone erosion and infection, it is for most of the complications of chronic otitis and fully justifies the adjective "dangerous" applied to chronic cholesteatomatous otitis.