Isozyme differentiation of aldolase and pyruvate kinase in fetal,regenerating, preneoplastic,and malignant rat hepatocytes during culture

Summary Aldolase and pyruvate kinase isozymes were investigated in cultured hepatocytes from fetal, regenerating, and 2-acetyl-aminofluorene-fed rat liver as well as in some epithelial liver cell lines. Our results show that: (a) cell proliferation and prolonged expression of specific isozymes were found only in cultured hepatocytes from 17-day old fetuses; (b) the fetal type of pyruvate kinase expressed in regenerating and carcinogen-treated liver was temporarily lost only in cultured hepatocytes from regenerating liver; (c) the adult type of aldolase and pyruvate kinase was absent in one epithelial cell line derived from a carcinogen-treated liver and in the hepatoma tissue cell (HTC) line but was found in the Faza clone of the Reuber H₃₅ cell line during the 50 first passages in vitro; and (d) the isozyme pattern of pyruvate kinase was always more strongly shifted than that of aldolase. The observations suggest that: (a) hepatocytes from carcinogen-treated liver exhibit the same lack of ability to proliferate in primary culture as normal adult hepatocytes; (b) adult hepatocytes can produce fetal isozymes without prior cell division; (c) pyruvate kinase is a stronger marker of dedifferentiation (retrodifferentiation) than aldolase; and (d) regulatory processes of isozyme expression are different during ontogenesis, regeneration, and hepatocarcinogenesis. This work was supported by the “Institut National de la Santé et de la Recherche Médicale” and the “Fondation pour la Recherche Medicale Fran?aise”     

12pter → 12p 12.2: Possible assignment of human triose phosphate isomerase

Summary Red cell triose-phosphate isomerase (TPI) was determined, together with other enzymes, in three patients with chromosome 12 abnormalities.In patient No. 1 (trisomy of the segment 12pter 12q12) and in patient No. 2 (trisomy of the segment 12pter 12p12.1), the TPI activity was significantly increased. In patient No. 3 (deletion of the segment 12p11 12p12.2), the TPI activity was in the normal range. These results suggest that the human TPI locus is located on the chromosome 12 short arm, between 12pter and 12p12.2.Directeur de Recherches à l'I.N.S.E.R.M.     

Syntheses of 3-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-α-d-galactopyranose (“lacto-N-biose II”) and 3,4-di-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-d-galactopyranose

3- O-(2-Acetamido-2-deoxy-β-d-glucopyranosyl)-α-d-galactopyranose (10, “Lacto-N-biose II”) was synthesized by treatment of benzyl 6-O-allyl-2,4-di-O-benzyl-β-d-galactopyranoside with 2-methyl-(3,4,6-tri-O-acetyl-1,2-dideoxy-α-d-glucopyrano)[2,1-d]-2-oxazoline (5), followed by selective O-deallylation, O-deacetylation, and catalytic hydrogenolysis. Condensation of 5 with benzyl 6-O-allyl-2-O-benzyl-α-d-galactopyranoside, followed by removal of the protecting groups, gave 10 and a new, branched trisaccharide, 3,4-di-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-d-galactopyranose (27).     

Characterization of messenger RNA for aldolase B in adult and fetal human liver

High molecular weight cellular RNA was isolated from adult and fetal human liver tissue by a procedure of ethanol precipitation in concentrated guanidine-HCl solutions. About 5 mg of RNA were obtained from one gram of liver. RNA was fractionated by sucrose gradient ultracentrifugation. Aldolase B neosynthesized in a reticulocyte lysate cell-free system under the direction of total or fractionated RNA was purified by immunoaffinity microchromatography. Messenger RNA specifying synthesis of aldolase B exhibited a sedimentation coefficient of 16 S both in adult and fetal liver. This enzyme represented 1.3 % of the total neosynthesized proteins in adult liver, 0.1 % in the liver of a 6-month-old fetus and less than 0.01 % in the liver of a 4.5 month-old fetus.     

Relationship between the activity of the ethylene-forming enzyme and the level of intracellular 2,4-dichlorophenoxyacetic acid in pear cell culturesin vitro

Ethylene production by auxin-dependent pear cells culturedin vitro falls rapidly when they are deprived of 2,4-D. This phenomenon is associated with a decrease in ACC production. Readdition of 2,4-D causes a resumption of ACC production and ethylene synthesis. Ethylene-forming enzyme (EFE) activity, although never limiting, decreases sharply during 2,4-D depletion and rises again upon addition of 2,4-D. This increase in the EFE activity is not a rapid response to 2,4-D, since it requires several hours. Changes in EFE activity follow the same pattern as changes in 2,4-D concentration; the decrease in EFE activity is also concomitant with a decrease in the ability of 2,4-dinitrophenol to inhibit ethylene production. The possible role of auxins in the modulation of EFE activity is discussed.     

The Optomotor Response in Weak-electric Mormyrid Fish: Can they See?

The present study has explored the optomotor response in two species of mormyrid fish, Gnathonemus petersii and Brienomyrus niger. Both species tended to follow a black and white striped stimulus pattern under illumination levels of 6, 12, and 60 lx. The optomotor response ceased to occur under 540 lx. The behavioral data support earlier histological findings implicating the mormyrid retina in dim light vision.     

Ultrastructural evidence of oestradiol receptor by immunochemistry

Antiserum against calf uterus oestradiol receptor has been used for detecting oestradiol receptor in rat pituitary cells at the ultrastructural level after immunochemical reaction according to Sternberger. The gonadotropic, lactotropic and somatotropic cells were positive, but not the thyrotropic and corticotropic cells. In peripubertal and adult rats, both cytoplasmic and nuclear receptors were seen, but in a long-term castrated rat, the receptor was found only in the cytoplasm. After oestradiol administration to 21-day-old animals, the cytoplasmic receptor decreased and the nuclear receptor increased in gonadotropic cells, supporting the concept of hormone-receptor complex translocation. Antibodies against α1-foetoprotein demonstrated the presence of this oestrogen-binding plasma protein in all pituitary cells, but only in the cytoplasmic area. These results and the immunological controls related to antibody specificity give the first evidence of steroid receptor at the ultrastructural level.     

Diversity of trypanosomes in humans and cattle in the HAT foci Mandoul and Maro,Southern Chad—A matter of concern for zoonotic potential?

BackgroundAfrican trypanosomes are parasites mainly transmitted by tsetse flies. They cause trypanosomiasis in humans (HAT) and animals (AAT). In Chad, HAT/AAT are endemic. This study investigates the diversity and distribution of trypanosomes in Mandoul, an isolated area where a tsetse control campaign is ongoing, and Maro, an area bordering the Central African Republic (CAR) where the control had not started.Methods717 human and 540 cattle blood samples were collected, and 177 tsetse flies were caught. Trypanosomal DNA was detected using PCR targeting internal transcribed spacer 1 (ITS1) and glycosomal glyceraldehyde-3 phosphate dehydrogenase (gGAPDH), followed by amplicon sequencing.ResultsTrypanosomal DNA was identified in 14 human samples, 227 cattle samples, and in tsetse. Besides T. b. gambiense, T. congolense was detected in human in Maro. In Mandoul, DNA from an unknown Trypanosoma sp.-129-H was detected in a human with a history of a cured HAT infection and persisting symptoms. In cattle and tsetse samples from Maro, T. godfreyi and T. grayi were detected besides the known animal pathogens, in addition to T. theileri (in cattle) and T. simiae (in tsetse). Furthermore, in Maro, evidence for additional unknown trypanosomes was obtained in tsetse. In contrast, in the Mandoul area, only T. theileri, T. simiae, and T. vivax DNA was identified in cattle. Genetic diversity was most prominent in T. vivax and T. theileri.ConclusionTsetse control activities in Mandoul reduced the tsetse population and thus the pathogenic parasites. Nevertheless, T. theileri, T. vivax, and T. simiae are frequent in cattle suggesting transmission by other insect vectors. In contrast, in Maro, transhumance to/from Central African Republic and no tsetse control may have led to the high diversity and frequency of trypanosomes observed including HAT/AAT pathogenic species. Active HAT infections stress the need to enforce monitoring and control campaigns. Additionally, the diverse trypanosome species in humans and cattle indicate the necessity to investigate the infectivity of the unknown trypanosomes regarding their zoonotic potential. Finally, this study should be widened to other trypanosome hosts to capture the whole diversity of circulating trypanosomes.