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F Valle

Publications and source records attributed to F Valle.

72 records · Page 4Linked to original sources
PubMed1987

Determination of the nucleotide sequence for the glutamate synthase structural genes of Escherichia coli K-12.

We have determined the complete nucleotide sequence of a 6.3-kb chromosomal HpaI-EcoRI fragment, that contains the structural genes for both the large and small subunits of the Escherichia coli K-12 glutamate synthase (GOGAT) enzyme, as well as the 5'- and 3'-flanking and intercistronic DNA regions. The Mrs of the two subunits, as deduced from the nucleotide (nt) sequence, were estimated as 166,208 and 52,246. Partial amino acid sequence of the GOGAT enzyme revealed that the large subunit starts with a cysteine residue that is probably generated by a proteolytic cleavage. Northern blotting experiments revealed a transcript of approximately 7300 nt, that at least contains the cistrons for both subunits. A transcriptional start point and a functional promoter were identified in the 5' DNA flanking region of the large subunit gene. The messenger RNA nontranslated leader region has 120 nt and shares identity with the leader regions of E. coli ribosomal operons, in particular around the so-called boxA sequence implicated in antitermination. Other possible regulatory sequences are described.

Base Sequence↗
PubMed1987

[Behavior of arterial pressure during sports activity: track running].

In 6 normotensive and 14 borderline or mild hypertensive runners the intraarterial blood pressure (BP) changes determined by a maximal bicycle ergometric test and by an exhaustive run performed in outdoor conditions were recorded by means of the portable Oxford system. During running systolic BP attained higher values than during bicycle ergometry, while diastolic BP decreased during running and remained unchanged during ergometry. The highest BP values were recorded soon after starting running, then they progressively declined to increase once again during the final sprinting. Beat to beat analysis of the pressure tracings showed a peculiar pattern of the phasic waves throughout the run: continuous cyclic oscillations of pulse pressure were detected, as the variations of systolic blood pressure were not paralleled by those of the diastolic. The frequency of these rhythmic oscillations varied from 6-7 to 24-27/minute and was not related to respiration rate. The shape of these oscillations prompted us to investigate whether they were due to the "beat" phenomenon, that is to the combined effect of two waves with a nearly equal frequency. To verify this hypothesis 10 athletes during the run carried around the chest a Teruflex container filled with saline. The amplitude of the BP changes recorded in the container ranged from +/- 10 to +/- 50 mmHg. They were added by means of a computer to the BP tracing recorded during bicycle ergometry. The resultant wave was similar to that recorded in the radial artery during running.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Plasmid vector pBR322 and its special-purpose derivatives--a review.

The plasmid pBR322 was one of the first EK2 multipurpose cloning vectors to be designed and constructed (ten years ago) for the efficient cloning and selection of recombinant DNA molecules in Escherichia coli. This 4363-bp DNA molecule has been extensively used as a cloning vehicle because of its simplicity and the availability of its nucleotide sequence. The widespread use of pBR322 has prompted numerous studies into its molecular structure and function. These studies revealed two features that detract from the plasmid's effectiveness as a cloning vector: plasmid instability in the absence of selection and, the lack of a direct selection scheme for recombinant DNA molecules. Several vectors based on pBR322 have been constructed to overcome these limitations and to extend the vector's versatility to accommodate special cloning purposes. The objective of this review is to provide a survey of these derivative vectors and to summarize information currently available on pBR322.

Base Sequence↗
PubMed1986

Characterization of the regulatory region of the Escherichia coli penicillin acylase structural gene.

Penicillin acylase is utilized in the enzymatic production of semisynthetic penicillins. The enzyme is composed of two different subunits that originate from a common precursor. The partial nucleotide (nt) sequence of the structural gene has been published. This paper reports the nt sequence of the regulatory region of this gene, the identification of a functional promoter, the transcriptional start point, and the description of possible regulatory regions.

Amidohydrolases↗
PubMed1985

A common precursor for the two subunits of the penicillin acylase from Escherichia coli ATCC11105.

Penicillin acylase (PA) is an industrial enzyme that is used to convert penicillin G into a precursor for semisynthetic penicillins. We have cloned a segment of DNA that codes for the two subunits required for PA activity. We also report the nucleotide sequence of a DNA fragment that codes for (i) the small subunit, (ii) the N-terminal region of the large subunit and (iii) a putative connecting peptide. These results confirm the existence of a common precursor for both peptides.

Amidohydrolases↗
PubMed1985

Repetitive extragenic palindromic (REP) sequences in the Escherichia coli gdhA gene.

Deletions of the 3' flanking DNA region of the glutamate dehydrogenase (GDH) structural gene from Escherichia coli K-12, have been produced on a plasmid that carries the complete gdhA gene. Those deletions include part of the repetitive extragenic palindromic (REP) sequences proposed by Stern et al. [Cell 37 (1984) 1015-1026], as a novel and major feature of the bacterial genome. The effect of these deletions on the final GDH level in the cell, has been determined. A broader compilation, analysis and alternative functions of the REP sequences, is also presented.

Chromosome Deletion↗
PubMed1984

Complete nucleotide sequence of the glutamate dehydrogenase gene from Escherichia coli K-12.

A 2.3-kb PstI- ClaI chromosomal DNA segment, carrying the complete coding region of the glutamate dehydrogenase (GDH) structural gene from Escherichia coli K-12, has been sequenced. The complete amino acid sequence (447 residues) of the GDH monomer has been deduced, and comparisons are made with reported amino acid sequences of GDH from other organisms.

Amino Acid Sequence↗
PubMed1983

Nucleotide sequence of the promoter and amino-terminal coding region of the glutamate dehydrogenase structural gene of Escherichia coli.

A 610-bp DNA fragment carrying the promoter and amino-terminal coding regions of the glutamate dehydrogenase (GDH) structural gene from Escherichia coli has been sequenced. The amino-terminal sequence of the enzyme was also determined to help localize the transcriptional and translational signals for this gene. Three possible promoters and a CRP binding site were identified by concensus criteria. The sequence of 102 amino acids at the amino terminus of the enzyme is compared with the amino acid sequence from other GDH enzymes.

Animals↗
PubMed1982

Recombinant plasmids carrying the glutamate dehydrogenase structural gene from Escherichia coli K-12.

Plasmid pRSP1, isolated from the Escherichia coli gene bank of Clarke and Carbon (1975), has been shown to complement the gdh-1 mutation that affects the synthesis of glutamate dehydrogenase (GDH) in the E. coli strain PA340. The GDH structural gene of E. coli is present on a 2.3-Md DNA fragment from the hybrid plasmid pRSP1 and certain of its derivatives. Polypeptides synthesized by minicells carrying some of these plasmids, enabled us to make a preliminary determination of the direction of transcription of the gdh gene on the cloned fragments.

Chromosome Mapping↗
PubMedDate not supplied

Stimulation of glucose catabolism through the pentose pathway by the absence of the two pyruvate kinase isoenzymes in Escherichia coli.

Escherichia coli strains devoid of one or both of the two pyruvate kinase isoenzymes (PKA and PKF), were grown on minimal media in batch fermentations. The strain lacking both PKs showed a 28% decrease on its specific growth rate when compared to the wild type. However, protein and CO2 yields did not change. Using radioactive 1-C14 glucose and collecting the CO2 produced by the cultures, it was found that the mutant lacking both pyruvate kinases, metabolized glucose mainly through the pentose pathway (PP). The increased participation of the PP in glucose metabolism in this strain, was also reflected on the levels of the glucose-6-phosphate and 6-phosphogluconate dehydrogenases.

Escherichia coli↗
PubMedDate not supplied

Modifications in the serum concentrations of prolyl hydroxylase in patients with chronic hepatitis B during and after interferon therapy.

A total of eight patients with chronic active HBsAg-positive hepatitis was treated with recombinant interferon-alpha 2b for 12 months and serum aspartate aminotransferase, alanine aminotransferase, gamma-globulin and prolyl hydroxylase concentrations were determined every 3 months. Liver biopsies after 12 months' treatment revealed a significant (P less than 0.05) reduction in the histological activity score. After 6 months, alanine aminotransferase (P less than 0.01) and aspartate aminotransferase (P less than 0.05) concentrations fell significantly compared with baseline concentrations. Serum prolyl hydroxylase concentrations declined significantly (P less than 0.05) after 15 months and remained depressed. It is concluded that interferon-alpha 2b therapy reduced fibrogenetic activity in chronic active hepatitis B.

Adult↗
PubMedDate not supplied

Molecular cloning of the gene that codes for the pyruvate kinase of Bacillus subtilis: primary characterization of a strain carrying this gene insertionally inactivated.

We have cloned and characterized the pykA gene from Bacillus subtilis which codes for a pyruvate kinase (PK) enzyme. This gene has been located downstream a putative phosphofructokinase gene, suggesting that they are part of the same operon. The deduced amino acid sequence of this PK showed a strong similarity to other PKs from different sources; however, as it has been found in other bacilli, the B. subtilis pykA enzyme had an extra C-terminal sequence consisting of about 112 amino acid residues. This gene was insertionally inactivated at the chromosomal level, with an antibiotic resistance marker. The analysis of this mutation in wild type and pts- backgrounds, indicated that B. subtilis has no other pyruvate kinase activity capable of complementing the absence of PykA.

Amino Acid Sequence↗
PubMedDate not supplied

Long term therapy with recombinant interferon alpha 2 b in patients with chronic hepatitis C: effects on thyroid function and autoantibodies.

Twelve anti HCV-positive patients (8 males and 4 females; 37-62 yrs) suffering from chronic active viral hepatitis have been evaluated in order to determine serum thyroid hormones and autoantibody pattern during recombinant interferon alpha 2b (IFN-alpha 2b) therapy. The interferon was given subcutaneously three times per week for six months in a single standard dose of 3 MU. For a further six months 5 patients (Group A) received the same interferon at 1MU dose three times per week and 7 (Group B) had no treatment. Serum T3, T4, FT4, TBG, TSH, TGAb and TMAb were determined on serum collected before the start of the treatment and every month for 12 months thereafter. Except for one case, in which a transient reduction in thyroid hormone values and an increase in TSH levels was recorded, none of the patients studied showed a significant variation of serum hormonal parameters or appearance of pathological TGAb and/or TMAb levels. The data indicate that the administration of recombinant IFN-alpha 2b to HCV positive chronic active hepatitis patients at the dose and schedule employed in the present study may result in a reduction in the incidence of thyroid dysfunction related to the IFN therapy.

Adult↗
PubMedDate not supplied

Annual, daily and diurnal variations in pollen from Olea europaea L. in the atmosphere of Granada (Spain).

The allergenic capacity of Olea europaea L. pollen is very important in several cities of the southern Iberian Peninsula, producing most pollinoses diagnosed in these cities. We have carried out a study on the annual, daily and diurnal variations in pollen from O. europaea in the atmosphere of Granada (Spain) during 4 consecutive years. Samplings were carried out with the aid of a Burkard spore trap. Very low levels of Olea pollen grains were first detected in the atmosphere from the end of April. Pollen levels peaked in May and June, and started to decrease from the last days of June and in July. Pollen in the atmosphere is related to meteorological parameters: temperature has a positive influence on pollinization and rainfall produces a negative effect. The diurnal variation pattern of pollen grain concentrations was quite homogeneous throughout the study, featuring an important increase around midday and a moderate decrease in the first hours of the morning and in the late evening.

Air Pollution↗