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Biomedical subjects

A Miano

Publications and source records attributed to A Miano.

At least 37 records · Page 2Linked to original sources
PubMed1992

Epidermal inhibitory pentapeptide phosphorylated in vitro by calf thymus protein kinase NII is protected from serum enzyme hydrolysis.

In this paper, we demonstrate that synthetic epidermal mitosis inhibiting pentapeptide (pyroGlu-Glu-Asp-Ser-Gly) is phosphorylated in vitro at serine level by protein kinase NII isolated from calf thymus chromatin. A serum enzyme, which rapidly cleaves the synthetic epidermal mitosis inhibiting pentapeptide, also hydrolyses the synthetic transcription inhibiting pentapeptide (pyroGlu-Ala-Glu-Ser-Asn). The phosphorylated forms of both pentapeptides are protected from the serum enzyme activity.

Amino Acid Sequence↗
PubMed1992

Small acidic peptides from wheat germ chromatin. II. Regulatory activity in specific transcription systems reconstituted in vitro.

A variety of evidence suggests that a family of chromatin peptides (CPs), characterized by 1000D molecular weight, a pH dependent association to DNA and a prevailing presence of acidic amino acids in their structure, is involved in the regulation of genes expression. Nevertheless their action mechanism is still unknown. In our in vitro specific RNA transcription systems the CPs affect the initiation and not the elongation. Furthermore they inhibit the RNA transcription by interaction with the DNA rather than with the enzyme. The phagic in vitro specific RNA transcription is less affected by CPs than the eubacteric system, suggesting a kind of selectivity for target DNA sequences involved in the initiation of transcription.

Chromatin↗
PubMed1992

Small acidic peptides from wheat germ chromatin. I. Isolation and biochemical characterization.

RNA synthesis in cell and cell-free systems is inhibited by a family of acidic, low molecular weight chromatin peptides (CPs). These peptides were extracted from deproteinized DNA of prokaryotic and eukaryotic cells, but the low yield of purified material by this procedure hinders efforts aimed at understanding their action mechanism in gene regulation. In this report we describe two purification methods of CPs from an easily available source, wheat germ. A comparison is made between the method starting from deproteinized DNA and the method from purified chromatin. The biological effects (inhibition of L1210 cell growth and DNA in vitro transcription) of CPs from wheat germ together with their chemical characteristics (molecular weight, amino acid composition and presence of phosphoserine) show strong homology with those of CPs from other sources. These results suggest a possible role of these chromatin peptides in controlling gene expression.

Amino Acids↗
PubMed1991

Acidic pentapeptide phosphorylated in vitro by calf thymus protein kinase NII binds to DNA in the presence of Mg2+ cations.

The pentapeptide pyroGlu-Ala-Glu-Ser-Asn has been synthetized and phosphorylated in vitro at level of serine by protein kinase NII isolated from calf thymus chromatin. It is noteworthy that the calf thymus kinase NII shows a remarkable affinity for this peptide. The [32P]peptide is able to bind to several DNAs in the presence of Mg2+ (lambda phage, calf thymus, pBR540 plasmid). This binding appears not specific with regard to the type of DNA and its base sequence. These data support the hypothesis that phosphorylated acidic domains of nuclear nonhistone proteins could bind directly to DNA in the presence of Mg2+ cations.

Amino Acid Sequence↗
PubMed1991

Small acidic peptides are bound to E. coli DNA.

Low molecular weight peptides have been isolated by alkali extraction from deproteinized DNA of E. coli cells grown in the presence of radioactive glutamic acid or orthophosphate. The labeled peptides, purified by gel filtration chromatography on Sephadex G25 and G10, contain prevailingly glutamic acid, aspartic acid, glycine, serine and alanine. Electrophoretic studies at different pH show that some peptide fractions contain a phosphoric residue. The N-terminus of the phosphorylated peptides is apparently blocked and they were able to bind to DNA in the presence of Mg2+ ions. Moreover the acidic peptides extracted from E. coli DNA show a sharp activity in the control of lambda phage DNA transcription 'in vitro'.

Amino Acids↗
PubMed1989

Exercise tolerance and effects of training in young patients with cystic fibrosis and mild airway obstruction.

We evaluated the effects of an 8-week aerobic training (1 hr, three times a week) on physical performance of ten patients with cystic fibrosis (CF) (median age, 12.5 yr; range 11.1-15.3 yr), with mild airway obstruction (FEV1 = 77 +/- 22% pred.), and ten healthy age-matched children (CONTR) (median age, 12.7 yr; range 12.2-15.2 yr). Physical performance was tested with maximal incremental (MAX) and submaximal (SMAX) (fixed workload of 1.7 W/kg during 6 min) exercise tests on a cycle ergometer. These and standard spirometric and anthropometric measurements were performed at the beginning and end of a period with usual daily activity and one with the training program. The kinetics of ventilatory parameters at the onset and end of SMAX were displayed by fitting data on oxygen uptake and minute ventilation by monoexponential curves (least-squares method). At the start and the end of the training period, all children were timed for endurance run to voluntary exhaustion and for sprinting through an obstacle course. A pattern of relative hyperventilation during SMAX and of poor performance in endurance and obstacle runs were evident at the start of the training period in patients with CF. The effects of training on MAX and SMAX were small and partial; the improvement in field test performances was significant only for CF and could be attributed to improvement of skill and motivation.

Adolescent↗
PubMed1989

Synthetic model peptides phosphorylated in vitro by NII kinase and cation-mediated interactions with DNA.

Minimum substrate requirements for nuclear NII kinase (casein II kinase) were analyzed with synthetic peptides modeled according to amino acid composition of phosphopeptides isolated from chromatin. Uncharged blocked peptide termini decreased the requirement for acidic clusters neighboring the phosphate acceptor amino acid (serine) such that only one group immediately N-terminal to serine was sufficient for kinase activity. Studies on peptide interaction with DNA showed that the model phosphopeptides bound to DNA only in the phosphorylated form suggesting involvement of phosphorylation in protein-DNA interactions yet to be identified.

Amino Acid Sequence↗
PubMed1988

Isolation and characterization of small phosphorylated peptides controlling transcription "in vitro" from trout testis chromatin DNA.

Low molecular weight peptides are linked to the chromatin DNA of several tissues, from which they can be dissociated by alkaline extraction. They show very high specific activity in the control of transcription "in vitro". In this work the biochemical properties of controlling transcription peptide effectors isolated from trout testis DNA are reported. The purified peptides prevailingly contain glutamic acid, serine, aspartic acid, glycine and alanine. Studies of the peptide structure by N-terminal analysis using the dansyl chloride procedure was unsuccessful, suggesting the presence of a blocked NH2 group. At the same time the active peptides cannot be digested by carboxypeptidases. The gel filtration of the chromatin peptidic fractions on Sephadex G-25, Trisacryl GF05 or Sephadex G-15 shows that the active peptides elute as a single major peak with an elution volume corresponding to a molecular weight of about 1000. The paper electrophoresis performed at different pH and ionic strength shows that the chromatin peptides are separated in two fractions. One of them is strongly acidic and migrates towards the positive pole until pH 1.9, indicating the presence of phosphoric residues which probably exert an important role in the control of transcription "in vitro". The chromatin peptides are further purified by Sephadex G-10 and high performance liquid chromatography. The amino acid analysis of the purified peptides are reported.

Amino Acids↗
PubMed1981

[Hypertrophic exudative gastropathy in a child. A case report].

Case report of a four-year-old atopic boy with protein-losing hypertrophic gastropathy. The diagnosis was confirmed radiologically and with radioisotope examinations. Already after one week of a high protein diet, spontaneous remission occurred, accompanied by an asthmatic attack.

Child, Preschool↗
PubMed1977

Neonatal haemophilus aphrophilus meningitis.

Case report of a neonatal meningitis due to Haemophilus influenzae. The treatment with ampicillin was ineffective because of insensitivity. This case demonstrates the importance of a proper bacteriological identification in order to avoid ineffective or delayed treatment.

Ampicillin↗