Complexes of vanadium(III) with L-alanine and L-aspartic acid

The equilibria of the complexation processes of V(3+) with L-alanine and L-aspartic acid in aqueous solution over a wide pH range (2-10) were studied by potentiometric and spectroscopic (UV-Vis, CD) methods. The results show that alanine forms complexes with V(3+) in the metal ion concentration range and at the ligand-to-metal ratios investigated, giving mononuclear species only. In ML(2) species, which dominate in the range pH 4-8, alanine acts as a bidendate ligand through O and N atoms. The complexation processes of V(3+) with aspartic acid are more complicated. In acidic solution (up to pH approximately 4) they are similar to those for alanine. In the higher pH region, however, there are complicated equilibria among mono- and various dinuclear species. These dinuclear species consist of carboxylic or mu-oxo bridges and differ from each other by the number of coordinated ligands and OH(-) groups. The solid phase of the V(III) complex with aspartic acid could be isolated from nonaqueous solution only. Spectroscopic (UV-Vis-IR) measurements and magnetic susceptibility data confirm the coordination of vanadium(III) by two carboxylic groups. Both V(III)-L-aspartic acid and V(III)-L-alanine complexes have a significant apoptotic effect on Hepatoma Morris 5123 cells.     

Structure and unexpected chiroptical properties of chiral 4-pyrrolidinyl substituted 2(5H)-furanones

Planar 2(5H)-furanones substituted at C4 with a chiral pyrrolidinyl group show CD spectra which are apparently due to the distortion of the C4-N1 bond of sp2 character from the plane defined by the 2(5H)-furanone ring atoms and/or due to the presence of substituents in the pyrrolidine ring. This is a new, previously not encountered structural factor determining the chiroptical properties of 2(5H)-furanones and emerging from the analysis of X-ray diffraction data and quantum mechanical DFT computations. In the presence of a C5 pseudoaxial substituent in the furanone ring, the sign of the furanone n-pi* and pi-pi* transition Cotton effects is determined primarily by the previously postulated allylic helicity rule.     

Three novel mutations in exon 21 encoding beta-cardiac myosin heavy chain

Familial hypertrophic cardiomyopathy has a complex multigenic background. Previous work allowed to determine one of the gene loci responsible for this disease on chromosome 14 band q11-q12, and linked it to the alpha and beta-cardiac myosin heavy chains. In this study we demonstrate changes in exon 21, coding for beta-myosin heavy chain. We described 4 patients from different families with an unequivocal diagnosis of hypertrophic cardiomyopathy based on the clinical picture. Direct sequencing of exon 21 revealed the presence of 5 novel mutations. Two of the mutations in codons 771 and 781 revealed in our study did not result in any changes in amino acid sequence. The next three were as follows: in codon 782 (AGC > GAC) transition responsible for Ser-->Asp substitution; in codon 779 (GAG > TAG) mutation that results in replacement of Glu-->Stop; in codon 774 (GAG > GTG) which is expressed as substitution of Glu-->Val. These mutations are located close to mutations identified and described in the literature, so they are likely to cause similar symptoms.     

An approach to identification of rye chromosomes affecting the pre-harvest sprouting in triticale

The influence of the rye genome on triticale pre-harvest sprouting (PHS) resistance was studied by using Presto substitution lines, where rye chromosomes were substituted by the D genome of wheat. The PHS resistance was evaluated on the third, sixth and ninth day of a mist chamber test as a percentage of germinated kernels. All the substitution lines, except 6D(6R), showed a higher PHS resistance than cv. Presto, which means that the rye component of triticale influences negatively the triticale PHS resistance. The 2D(2R) line was the most resistant (finally 16% of sprouted grains). In all the lines, except 5D(5R), the sprouting dynamics was nearly linear during the experiment. The lowest increase in number of sprouted kernels (up to 7%) was observed in lines 3D(3R), 2D(2R) and 6D(6R) within the first three days of the mist-chamber test, but at the end of the experiment line 6D(6R) showed the highest PHS susceptibility (56% of sprouted grains). The fastest grain germination in spikes was observed for the 5D(5R) line. Thus a simple and cheap modernization of the mist-chamber test, by additional evaluation of the lag phase and the initial germination in spikes during the first three days, is suggested for selection of genotypes with higher potential of PHS avoidance.     

Maternal-fetal distribution and prenatal toxicity of 2,2,4-trimethyl-1,2-dihydroquinoline in the rat

BACKGROUND: Polnoks R (poly‐2,2,4‐trimethyl‐1,2‐dihydroquinoline) is used as an antioxidant in elastomer processing. It is an embryotoxic and fetotoxic agent. This chemical given per os to female rats induces also teratogenic effect but only at doses toxic to the mother. The aim of the study was to evaluate prenatal development and tissue distribution in rats exposed to 2,2,4‐trimethyl‐1,2‐dihydroquinoline (TMDHQ), a monomer of Polnoks R. METHODS: Females were exposed orally to unlabeled TMDHQ during organogenesis at doses 50–400 mg/kg to asses prenatal toxicity and to radiolabeled ¹⁴C monomer at a dose 210 mg/kg to evaluate tissues distribution. RESULTS: TMDHQ administered to pregnant females per os at doses 100 mg/kg and higher produced teratogenic effect (cleft palate, wavy ribs, kyphoscoliosis, exencephaly, external hydrocephalus, hydronephrosis, and renal hypoplasia). Peak ¹⁴C‐radioactivity was found in mothers' plasma about 10 hr after administration of this compound at dose 210 mg/kg. The accretion of ¹⁴C proceeded with a kinetic constant of 0.35 hr ^?1 and a half‐life of 53.3 hr. Kidneys are the main organs of monomer excretion. The highest concentration of ¹⁴C in maternal tissues 24 hr after oral dosing was found in adipose tissue, sciatic nerve, muscles, kidneys, and liver. Radiocarbon retention in fetuses was the highest in kidneys at all time points after dosing. CONCLUSIONS: This study has demonstrated that transplacental exposure to Polnoks R monomer is teratogenic in rats. ¹⁴C retention in placenta, amniotic fluid, and fetal tissues indicates that this compound or its metabolites penetrate into placenta to the fetus. Birth Defects Res B 68:375–382, 2003. © 2003 Wiley‐Liss, Inc.     

Development of the tongue and taste disks in Pelobates fuscus

In the tadpole of Pelobates fuscus the process of tongue formation starts at the 32nd developmental stage. In more advanced stages (older than 38th) fast anterior and faucial growth of the tongue fold has been observed. This process is accompanied by the development of the gustatory organs. The dorsal surface of the tongue fold, smooth at the beginning, in older tadpoles (developmental stages 36-39th) forms protrusions in which gustatory organs of the taste disk type (TDs) develop. In the 41 st tadpole developmental stage anlages of TDs are formed by elongated cells, located more or less perpendicularly to the surface of the tongue. The diameter of the sensory area of a TD at the 45th developmental stage amounts to 94 microm, while in metamorphosed individuals it reaches 130-140 microm. At the base of a TD the presence of basal cell morphologically similar to that of Merkel cell was observed at the 42nd developmental stage of a tadpole. Fully developed afferent synaptic connections in the sensory epithelium of a TD were found starting from the 44th developmental stage. Single synaptic vesicles with an electron-dense core were observed in gustatory cells as early as at the 41 st developmental stage of the tadpole. From the observations reported here it can be inferred that in Pelobates fuscus development of both the tongue and TDs is similar to that already described in the representatives of the Rana genus.     

Microsatellite polymorphism in locus OMHC1 (MHC Class I) in Polish Heath Sheep and Polish Lowland Sheep (Zelazna variety)

Our study aimed at comparative analysis of microsatellite polymorphism in locus OMHC1 (MHC Class I) in Polish Heath Sheep and Polish Lowland Sheep (Zelazna variety). The study was conducted on 100 ewes of each breed. We identified 13 alleles of the gene in Polish Heath Sheep and 9 in Polish Lowland Sheep. We found marked differences in frequency of OMHC1 alleles between both breeds. The heterozygosity coefficient and PIC, amounting to 0.79 and 0.77 for Polish Heath Sheep, and 0.82 and 0.80 for Polish Lowland Sheep, respectively, suggest considerable variability in both breeds. Additionally, the values of both coefficients indicate that OMHC1 locus can be used as a genetic marker.