Nativity of the macromolecule of isologous DNA as a condition for its reparative effect on radiation damage

The effect of isologous DNA on the course of postirradiation reparation of meristematic cells ofVicia faba primary roots was studied in detail. A considerable interest was devoted to determinations of fundamental qualitative and quantitative conditions of the above effect of isologous DNA. Main criteria of the effect were both mitotic activity of irradiated cellular population and dynamics of chromosome aberrations induced by radiation. One set of experiments compared the course of reparation as occurred in regard to applied dose of ionizing radiation in native isologous DNA, DNA denaturated by heat and degraded by DNAase, and post-irradiation reparation of induced damages was favorably affected by native isologous DNA only. Another set of results evaluated the dependence of positive reparative effect of native isologous DNA on the length of the molecule demonstrating that in the process of reparation the presence of a complete DNA macromolecule was not essential. The last experimental group was focused on observations on the dependence of the rate of native isologous DNA effect on concentration of applied solution of the macromolecule.     

Antimicrobial agents

In a study of the effect of progesterone, its hydroxy derivatives and various sterols on the growth of dermatophytes, it was demonstrated that all the steroid compounds employed inhibited growth of the 51 strains of dermatophytes tested. No significant differences were found in sensitivity to the given steroids, either in dermatophyte strains of the same species, but of different origin, ior in different species of the four genera used (Trichophyton, Microsporum, Epidermophyton andKeratinomyces). Hydroxylation of the progesterone molecule in any except the C-21 position lowered the inhibitory effect. The course of the transformation reaction on the progesterone or cholesterol molecule was likewise of a uniform character from the aspect of species specificity. Progesterone was simultaneously hydroxylated in positions 15α and 15β by all the strains, giving rise to monohydroxy-derivatives as the main metabolites, and cholesterol was oxidized to cholestenone.     

Dicentric chromosome due to an unusual fusion

Summary The case of a very mild 18p—syndrome is reported. In a mentaly retarded girl was recovered karyotype with 45 chromosomes. The absent chromosomes G and E (18) were replaced by a submetacentric, dicentric chromosome, originated from an unusual fusion. The examination of serum immunoglobulins revealed the deficiency of IgA.

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Zusammenfassung Es wird über einen Fall von mäßigem 18p—Syndrom berichtet. Bei einem mentalretardierten Mädchen wurde ein Karyotyp mit 45 Chromosomen festgestellt. Das fällende Chromosom war mit einem submetazentrischen und gleichzeitig dizentrischen Chromosom ersetzt, das durch eine sehr ungewöhnliche Fusion entstand. Die Untersuchung der Immunglobuline hat einen deutlichen -A-Globulin-Mangel gezeigt.

     

Teratocarcinogenesis as related to the age of embryos grafted under the kidney capsule

Summary Mouse egg-cylinders of C3H/H strain with two and three germ layers were transplanted under the kidney capsule. They developed into well differentiated teratomas and teratocarcinomas. Older embryos developed invariably into teratomas composed of adult tissues only. We consider the period of germ layer inversion as a critical stage when embryonic cells loose their potentiality for uncontrolled growth.     

Synthesis and rearrangements of D-glucosyl esters of aspartic acid linked through the 1- or 4-carboxyl group.

Catalytic hydrogenation of 2,3,4,6-tetra-O-benzyl-1-O-[1-benzyl N-(benzyloxycarbonyl)-L-aspart-4-oyl]-alpha-D-glucopyranose (1alpha) in acetic acid-2-methoxyethanol gave 1-O-(L-beta-aspartyl)alpha-D-glucopyranose (2alpha) contaminated with 2-O-(L-alpha-aspartyl)-D-glucopyranose (8). Evidence that 8 was formed from the 1-oyl isomer of 1alpha, namely 2,3,4,6-tetra-O-benzyl-1-O-[4-benzyl N-(benzyloxycarbonyl)-L-aspart-1-oyl]-alpha-D-glucopyranose (7alpha), via 1 leads to 2 acyl migration, was obtained by submitting the deprotected D-glucosyl ester to successive N-acetylation, esterification, and O-acetylation; the final product was identified as a approximately 4:1 mixture of 2,3,4,6-tetra-O-acetyl-1-O-[1-methyl N-(acetyl)-L-aspart-4-oyl]-alpha-D-glucopyranose (4alpha) and 1,3,4,6-tetra-O-acetyl-2-O-[4-methyl N-(acetyl)-L-aspart-1-oyl]-D-glucopyranose (6) which were also prepared by definitive methods. On the other hand, deprotection of 1beta gave isomerically pure 2beta which was converted into the peracetylated ester derivative 4beta; an explanation for the differences in aglycon isomeric purity of 2alpha and 2beta is given. Hydrogenolysis of 7beta under the above conditions led to intermolecular transesterification with scission of the C-1 ester bond to give 1-(2-methoxyethyl) L-aspartic acid and D-glucose. Catalytic hydrogenation of 7alpha and 7beta, performed in the presence of trifluoroacetic acid, afforded 1-O-(L-alpha-aspartyl)-alpha- and -beta-D-glucopyranoside trifluoroacetate salts (11alpha and 11beta), respectively. The structure of 11beta was established by successive conversion into 2,3,4,6-tetra-O-acetyl-1-O-[4-methyl N-(acetyl)-L-aspart-1-oyl]-beta-D-glucopyranose (5beta) which was also prepared by definitive methods. Analogous treatment of 11alpha gave the N-acetyl derivative 12 which underwent 1 leads to 2 acyl migration during esterification with diazomethane to give the N-acetyl methyl ester derivative 10; acetylation of 10 afforded 6.     

Effect of hydration level in primary bean leaves on the activity of photosystems 1 and 2 in isolated chloroplasts

Water stress in the leaves was induced by gradual decreasing of substrate moisture in five-day cycles.The hydration level of the leaves was characterized by their water potential (ψ_w), osmotic potential (ψ_s), pressure potential ψ_p and water saturation deficit(ΔW _sat ).The activities of Photosystems 1 and 2 were determined polarographically with Pt/Ag(AgOH) electrode as changes in oxygen concentration in chloroplast suspensions. The shape of light curves of Hill reaction was not influenced by leaf (ψ_w), hence both quantum efficiency and dark phase of this process were affected in a similar manner by water deficit. The activities of both photosystems measured at saturating photon flux density declined with the lowering of leaf (ψ_w) (in the range from -5 to -14 x 10⁵ Pa) and the decrease in activity of Photosystem 2 was more rapid than that of Photosystem 1. The ratio of activities of Photosystems 1 and 2 was mildly enhanced by a lowering of (ψ_w), but it decreased with increasing age. The lowering of ψ_winduced lowering in the chlorophyll a/b ratio thus concealing the usual ontogenetic course of this ratio.     

Effect of crotonaldehyde on the metabolism ofCandida utilis during the production of single cell protein from ethanol

The effect of 20 low-boiling compounds on the yeastCandida utilis 49 was assessed by a screening test on agar medium. The highest toxicity was exhibited by crotonaldehyde, allyl alcohol and acrolein. Oxidation and assimilation experiments in a slightly aerobic environment showed that an increase in the level of crotonaldehyde in the medium in the range of 10–200 mg 1⁻¹ brings about a lowering of intensity of metabolic processes inCandida utilis, suppression of ethanol utilization and aerobic oxidation rate, a drop in biomass yield, prolongation of cultivation time,etc. The inhibitory effect of crotonaldehyde depends strongly on the manner of its dosage into the medium (single or continuous) and other cultivation conditions (intensity of medium aeration, physiological state of the culture,etc). Crotonaldehyde is lost from the medium partially by volatilization and partially due to chemical and biochemical transformation.     

The values of alpha 2-macroglobulin in the serum of persons at work with X-rays

Summary A group of 86 persons (65 women, 21 men) working at the risk of ionizing radiation (IR) was examined for the levels of alpha 2-macroglobulin ( ₂-M), and compared to a group of an age matched healthy population. Whereas the difference in men did not reach a level of significance, significant difference was assessed in women: in a subgroup older than 40 y exposed to the IR a rise of ₂-M levels was noted in correlation with the age. Multiple correlation coefficients showed a synergistic influence of both age and exposure to IR. The results are discussed from the point of view of the hypothesis that in exposed women a shifting realizes of usual old age changes to younger age group. A possibility is suggested to use the examination of ₂-M levels for preventive control of workers at the risk of IR.     

Effects of prostaglandin PGE2 on the synthesis of placental proteins and human placental lactogen (HPL)

The biosynthesis of placental proteins and placental lactogen (HPL) was studied $\text{in vitro}$ in 10–12 week, 16–18 week and term human placenta in the presence and absence of PGE_2α. The highest ¹⁴C-leucine incorporation was detected in 10 to 12 weeks old placentas. Addition of PGE_2α to the induction medium depressed the rate of incorporation of ¹⁴C-leucine into placental proteins on a dose dependent manner. Placentas most sensitive to this action of PGE_2α were those obtained at 18 weeks gestation followed by placentas at term. $\text{In vivo}$ application of PGE_2α for tharapeutic induction of abortions resulted in the marked inhibition of placental protein synthesis $\text{in vitro}$.     

Polymorphism of transferrin in carp (Cyprinus carpio L.): Genetic determination,isolation, and partial characterization

Seven transferrin variants (A, B, C, D, E, F, and G) have been found in carp sera (Cyprinus carpio L.). Genetic analysis involves five variants and agrees with the hypothesis of simple codominant autosomal inheritance at one transferrin (Tf) locus in spite of the fact that the carp is a tetraploid in relation to other species of the same family. Carp populations from three regions were studied which differed in gene frequencies. Individual populations were in Hardy—Weinberg equilibrium. The polymorphism of carp transferrins can be used for the identification of offspring of single parent pairs, stocked in one pond. Transferrins have been isolated and characterized. Homozygous phenotypes comprised four iron-binding components differing in electrophoretic mobility. This heterogeneity is not caused by sialic acid, which is absent. Amino acid composition, content of hexoses (1 mole/mole of protein) and hexosamines (1 mole/mole of protein), molecular weight (70,000), and the isoelectric point (5.0) have been determined. No N-terminal amino acid could be detected.