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Biomedical subjects

A Krzyzaniak

Publications and source records attributed to A Krzyzaniak.

At least 19 recordsLinked to original sources
PubMed2003

Secular changes in body height and weight in children and adolescents in Poznan, Poland, between 1880 and 2000.

AIM: A secular trend in body height and weight is well documented. The first observations concerning this phenomenon in Poland were made at the end of the 19th century. The aim of this study was to assess changes in body height and weight during the 20th century, with special emphasis on the last decade. METHODS: The results of body height and weight measurements obtained in eight subsequent surveys (1880-1886, 1922-1927, 1946-1950, 1960-1961, 1970-1971, 1980-1981, 1990-1991 and 1999-2000) were included in the analysis. Mean values were compared and differences between the surveys were analysed. RESULTS: In general, in the 20th century, children grew taller and heavier and reached final body height and weight more rapidly. The biggest differences in body height and weight in the 20th century, observed at growth spurt, were about 17 cm and 11 kg, respectively, for boys, and 13 cm and 13 kg for girls. The magnitude of secular changes in body height and weight in the 20th century was not stable. There were periods of increased and decreased intensity of acceleration of physical development (the 1950s and 1970s, and the 1960s and 1980s, respectively), as well as a period of deceleration (the 1940s). In the last decade, the tendency has been towards deceleration in most age groups studied. CONCLUSION: The acceleration of physical development in children in Poznan has now ceased.

Adolescent↗
PubMed2000

Specific induction of Z-DNA conformation by a nuclear localization signal peptide of lupin glutaminyl tRNA synthetase.

Recently we have sequenced cDNA of plant glutaminyl-tRNA synthetase (GlnRS) from Lupinus luteus. At the N terminal part the protein contains a lysine rich polypeptide (KPKKKKEK), which is identical to a nuclear localization signal (NLS). In this paper we showed that two synthetic peptides (20 and 8 amino acids long), which were derived from lupin GlnRS containing the NLS sequence interact with DNA, but one of them (8aa long) changing its conformation from the B to the Z form. This observation clearly suggests that the presence of the NLS polypeptide in a leader sequence of GlnRS is required not only for protein transport into nucleus but also for regulation of a gene expression. This is the first report suggesting a role of the NLS signal peptide in structural changes of DNA.

Amino Acid Motifs↗
PubMed1998

tRNA aminoacylated at high pressure is a correct substrate for protein biosynthesis.

tRNA can be aminoacylated specifically with amino acids at high pressure of 6 kbar (1 bar = 1.013 atm = 0.1 MPa = 10(5) Pa) in the absence of the specific aminoacyl-tRNA synthetase and ATP. In this paper we present new evidence obtained by HPLC chromatography and TLC analysis that the esterification reaction under pressure really takes place at the 3' end of the tRNA molecule. If so, tRNA to be aminoacylated undergoes conformational changes similar to those induced with aminoacyl-tRNA synthetase. The most important finding is that aminoacyl-tRNA obtained at high pressure binds to ribosomes and participates in the synthesis of polyphenylalanine in vitro. This is the best proof of proper charging of tRNA at high pressure.

Acylation↗
PubMed1997

[Videonystagmography: a new diagnostic method in vertigo].

We present videonystagmography a new method of vertigo diagnosis. The camera record eye movement. We can obtain regostration of nystagmus in all directions. Simplicity of use and great sensitiveness of to examinations are very important two.

Electronystagmography↗
PubMed1996

Mass spectrometric amino acid sequencing of a mixture of seed storage proteins (napin) from Brassica napus, products of a multigene family.

The amino acid sequences of a number of closely related proteins ("napin") isolated from Brassica napus were determined by mass spectrometry without prior separation into individual components. Some of these proteins correspond to those previously deduced (napA, BngNAP1, and gNa), chiefly from DNA sequences. Others were found to differ to a varying extent (BngNAP1', BngNAP1A, BngNAP1B, BngNAP1C, gNa', and gNaA). The short chains of gNa and gNa' and of BngNAP1 and BngNAP1' differ by the replacement of N-terminal proline by pyroglutamic acid; the long chains of gNaA and BngNAP1B contain a six amino acid stretch, MQGQQM, which is present in gNa (according to its DNA sequence) but absent from BngNAP1 and BngNAP1C. These alternations of sequences between napin isoforms are most likely due to homologous recombination of the genetic material, but some of the changes may also be due to RNA editing. The amino acids that follow the untruncated C termini of those napin chains for which the DNA sequences are known (napA, BngNAP1, and gNa) are aromatic amino acids. This suggests that the processing of the proprotein leading to the C termini of the two chains is due to the action of a protease that specifically cleaves a G/S-F/Y/W bond.

2S Albumins, Plant↗
PubMed1996

High pressure effects on conformation of homo- and heteroduplexes of nucleic acids.

Four different chemically synthesized single stranded complementary oligonucleotides: DNA I, d(GCGCGCATATAT); RNA I, r(AUAUAUGCGCGC): RNA II, r(GGCCGGUUAAUU); and RNA III, r(AAUUAACCGGCC) were studied in order that the effects of high pressure on heteroduplex and homoduplex structures could be understood. The oligonucleotides were subjected to a high pressure at low and/or high salt buffer and analyzed by circular dichroism spectroscopy. In these conditions, both DNA-RNA and RNA-RNA duplexes with different purine-pyrimidine sequences change their conformation. The heteroduplex DNA I-RNA I with the complementary alternating purine-pyrimidine sequence, does not change its conformation of A type at high salt alone or at high salt and high pressure applied together. The homoduplex RNA II-RNA III with purine-purine-pyrimidine-pyrimidine sequence does not change strongly its. A-RNA conformation either. However, a structure of the homoduplex is affected by high pressure alone or with high salt as concluded from shifting the maximum of the CD spectrum to around 265 nm and inducing higher Cotton effect. These observations clearly suggest some conformational changes of the homoduplex. A single stranded oligonucleotide (RNA I) and oligodeoxynucleotide (DNA I) alone showed up a different conformation. The CD spectrum of RNA I is similar to that of A-RNA structure, out that of DNA I shows a very small Cotton effect and has not an ordered structure.

Circular Dichroism↗
PubMed1994

The non-enzymatic specific amino-acylation of transfer RNA at high pressure.

This paper shows that the phenylalanine-specific tRNA of Escherichia coli as well as the yellow lupin methionine initiator tRNAMet can be charged specifically with phenylalanine and methionine, respectively, in the absence of specific aminoacyl-tRNA synthetases, under high pressure of a maximum of 6 kbar (1 bar = 10(5) Pa; 1 atm = 1.01 x 10(5) Pa). The esterification reaction takes places at the 3' end of the tRNA molecules. The yield of Phe-tRNAPhe or Met-tRNAMet at high pressure is approximately 10 times lower than that of the enzymatic aminoacylation reaction. This reaction seems to be specific, and mis-aminoacylation of tRNAPhe and tRNAMet with serine is negligible. It is well known that tRNA undergoes conformational changes during interaction with an aminoacyl-tRNA synthetase. Similarly, on the basis of circular dichroism spectra, we showed that the conformation of tRNA at high pressure differs slightly from its original A-RNA form. Therefore, it can be speculated that the chargeable conformation of tRNA induced by the aminoacyl-tRNA synthetase during enzymatic aminoacylation and the one created at high pressure are similar and are most probably formed by a dehydration mechanism. We think that the 'unique' tertiary structure of tRNA existing under high pressure creates an active centre which might itself catalyse ester bond formation. Therefore, the structure of the amino acid stem of tRNA may determine (code) the charging of the particular amino acid to specific tRNA. This code is clearly distinct from the rules of the classical genetic code.

Acylation↗
PubMed1994

A-Z-RNA conformational changes effected by high pressure.

This paper reports evidence obtained by circular dichroism (CD) spectroscopy measurements indicating that two oligoribonucleotide duplexes with the alternating purine-pyrimidine sequences r(GC)6 or r(AU)6 change their A-RNA conformation under high pressure. Under the high-pressure conditions at which B-Z-DNA transition easily occurs, RNA acquires a conformation which only differs slightly from that of A-RNA. However, exposure of r(GC)6 or r(AU)6 to high pressure (6 kbar) in the presence of 5 M NaCl causes a conformation change of both oligoribonucleotide duplexes from their A- to their Z-RNA form. The departure of RNA or DNA duplexes from their original conformations under high pressure depends on the water structure itself and involves displacing an active (structural) water molecule outside the nucleic acid molecules. Experiments carried out until now in many laboratories have shown that B-Z or A-Z transitions of DNA or RNA, respectively, do not depend on the conditions applied, but the common mechanism for these processes seems to be dehydration. This same effect can be observed either at high salt concentrations or in the presence of an alcohol or at high pressure. Our results also support the view that the higher stability of RNA compared with DNA duplexes is due to the strong interaction of the 2'-hydroxyl groups of RNA with water molecules.

Circular Dichroism↗
PubMed1991

Specific incorporation of glycine into bacterial lipopolysaccharide. Novel function of specific transfer ribonucleic acids.

It has been found that the bacterial endotoxins (lipopolysaccharides, LPSs) contain some amino acids and glycine is the most abundant amino acid in the polysaccharide core preparations of LPSs of gram-negative bacteria. Until now nothing was known about the mechanism of amino acid incorporation into the lipopolysaccharide core. We found that one out of three glycyl-tRNAs(Gly) from Escherichia coli is the donor of amino acid and is the substrate for a putative aminoacyl-tRNA:LPS transferase. We have isolated, purified this tRNA and determined its nucleotide sequence to be major E.coli tRNA(3Gly). This tRNA(Gly) (anticodon GCC) conserved the tRNA structural features. The assay for determination of the specific incorporation of glycine into the lipopolysaccharide was also invented and described.

Acylation↗
PubMed1991

B-Z DNA reversible conformation changes effected by high pressure.

There are numerous data showing that a DNA molecule with alternate pirymidine-purine sequence can adopt a left-handed, double-helical Z-DNA conformation. Such structural changes of DNA occur as a consequence of environmental conditions (e.g. 4 M NaCl) or chemical modification (e.g. methylation or bromination of bases). In this paper, we found for the first time that high pressure (several kilobars) can change the DNA conformation from the B to the Z form. When the pressure is reduced to an atmospheric one, DNA conformation returns back to the B-form. The Z-DNA structure formation was confirmed by circular dichroism (CD) and ultraviolet (UV) measurements. However, we found, that the values of the ratio of absorbance at the wavelengths 295 and 257 nm in the range of 0.3-0.4 is not a fully conclusive proof for the Z-DNA conformation. Although the ratio is typical for Z-DNA form, it is not obvious that the negative band in CD spectrum will be observed. On the other hand, methylated DNA does not undergo B----Z DNA transitions at the high pressure. These conformational changes of DNA molecules could be interpreted as the effect a of different hydration of various DNA forms.

Circular Dichroism↗
PubMed1989

[Indices of development in children and adolescents of Poznan aged 3 through 18].

Mean values and standard deviations of the body weight and height were calculated for the particular age and sex groups od children and adolescents aged between 3 and 18 years in Poznań. The calculations were based on the results of examinations of 12,669 children: 6,941 girls and 5,728, i.e. 11% of the total population in Poznań (highly representative sample). Percentile nets and weight-height proportion nets were constructed.

Adolescent↗
PubMed1989

[Accelerated physical development of children and adolescents in Poznan].

The results of body height and weight measurements of 12,669 children and adolescents aged between 3 and 18 years carried out in the school year 1980/81 were compared with the measurements of the same features performed in the school population in Poznań during the last 100 years. A phenomenon of the physical development acceleration was confirmed, being a base for temporary actualization of the developmental standards.

Adolescent↗