The activity and distribution of gamma-glutamyl transpeptidase (y-GT) in human foetal organs.

The activity and distribution of y-GT was investigated in a number of organs from human foetuses aged from 14 to 24 weeks post menstruationem. Over this period, enzyme activity increased in the kidney, pancreas and thymus, but decreased in the small intestine. No trend could be established for the liver, although activity was high. In the lung, spleen, brain and adrenals, y-GT was either detectable at very low levels or could not be demonstrated. The possible relationship between y-GT activity in some human tumours and the enzyme level in the corresponding foetal organs is discussed.     

The activity and distribution of gamma-glutamyl transpeptidase (y-GT) in human lung cancers serially transplanted in nude mice.

Gamma-glutamyl transpeptidase (y-GT) activity and distribution were investigated in different types of human lung cancers (three epidermoid carcinomas, one large cell carcinoma) which were maintained by serial transplantation in nude mice. All transplanted tumour fragments were positive for the enzyme. In the epidermoid carcinomas, y-GT levels were related to the degree of tumour differentiation. Enzyme activity in tumour fragments was always higher than that found in normal adult human lung tissue, and was, in general, maintained throughout the transplantation series.     

The activity and distribution of gamma-glutamyl transpeptidase (y-GT) in human lung cancers serially transplanted in nude mice

Summary Gamma-glutamyl transpeptidase (y-GT) activity and distribution were investigated in different types of human lung cancers (three epidermoid carcinomas, one large cell carcinoma) which were maintained by serial transplantation in nude mice. All transplanted tumour fragments were positive for the enzyme. In the epidermoid carcinomas, y-GT levels were related to the degree of tumour differentiation. Enzyme activity in tumour fragments was always higher than that found in normal adult human lung tissue, and was, in general, maintained throughout the transplantation series.This work was supported by a grant from A.S.F.C., Switzerland, and the Jubiläumsspende 1970 der Zürcher KantonalbankN.F. was supported during part of the work by a Royal Society European Science Exchange Programme Fellowship     

Metabolism of retinaldehyde and other aldehydes in soluble extracts of human liver and kidney

Purification and characterization of enzymes metabolizing retinaldehyde, propionaldehyde, and octanaldehyde from four human livers and three kidneys were done to identify enzymes metabolizing retinaldehyde and their relationship to enzymes metabolizing other aldehydes. The tissue fractionation patterns from human liver and kidney were the same, indicating presence of the same enzymes in human liver and kidney. Moreover, in both organs the major NAD(+)-dependent retinaldehyde activity copurified with the propionaldehyde and octanaldehyde activities; in both organs the major NAD(+)-dependent retinaldehyde activity was associated with the E1 isozyme (coded for by aldh1 gene) of human aldehyde dehydrogenase. A small amount of NAD(+)-dependent retinaldehyde activity was associated with the E2 isozyme (product of aldh2 gene) of aldehyde dehydrogenase. Some NAD(+)-independent retinaldehyde activity in both organs was associated with aldehyde oxidase, which could be easily separated from dehydrogenases. Employing cellular retinoid-binding protein (CRBP), purified from human liver, demonstrated that E1 isozyme (but not E2 isozyme) could utilize CRBP-bound retinaldehyde as substrate, a feature thought to be specific to retinaldehyde dehydrogenases. This is the first report of CRBP-bound retinaldehyde functioning as substrate for aldehyde dehydrogenase of broad substrate specificity. Thus, it is concluded that in the human organism, retinaldehyde dehydrogenase (coded for by raldH1 gene) and broad substrate specificity E1 (a member of EC 1. 2.1.3 aldehyde dehydrogenase family) are the same enzyme. These results suggest that the E1 isozyme may be more important to alcoholism than the acetaldehyde-metabolizing enzyme, E2, because competition between acetaldehyde and retinaldehyde could result in abnormalities associated with vitamin A metabolism and alcoholism.     

Magnesium-dependent sphingomyelinase.

An enzyme which requires divalent metals and hydrolyses sphingomyelin to ceramide and phosphorylcholine is present in rat and human brain and practically absent from other organs. The greatest activity is associated with the microsomal fraction. It had an optimal pH at about 7.4, required magnesium or manganese ions and was completely inhibited by EDTA. Triton X-100 was required for optimal activity and this detergent could also be used to partly solubilize the enzyme from rat brain microsomes. Lecithin was hydrolyzed at only 2% of the corresponding rate of hydrolysis of sphingomyelin.     

Measurement of 1-aspartamido-beta-N-acetylglucosamine amidohydrolase activity in human tissues.

The activity of 1-aspartamido-beta-N-acetylglucosamine amidohydrolase (aspartylglucosylaminase, EC 3.5.1.26) was measured in normal and diseased human liver, brain and kidney. Organs from patients with aspartylglucosaminuria show very little activity. Crude homogenates of human organs show a reaction catalysed by a complex enzyme system. With homogenate, the formation of product was linear with time up to about 6 h. Reaction times longer than 6-7h resulted in a decrease in the total concentration of product. This phenomenon was not found with the partially purified enzyme fraction. Linearity of the enzyme activity with different protein concentrations was found, independent of the incubation time. Longer incubation of the crude homogenate resulted in the utilization of the product, N-acetylglucosamine. This phenomenon was not observed with the partially purified enzyme fraction. This amidase from human organs differs from that obtained from other sources and apparently represents a rather complex enzyme system.     

Endoglucanase activity in <Emphasis Type="Italic">Neoteredo reynei</Emphasis> (Bivalvia,Teredinidae) digestive organs and its content

Cellulolytic enzymes have been studied in several organisms, such as insects, molluscs and other organisms, which can have enzymes endogenously produced or by symbiotic microorganisms. These enzymes are responsible for breaking down the cellulosic material upon which these organisms feed, probably with the aim of assimilating the sugars and nutrients. As Teredinidae bivalves grown in mangrove trees, this study aimed to measure endo-β-1,4-glucanase activity in different organs and its content. Endo-β-1,4-glucanase activity was detected in different organs of the Teredinidae bivalves, including gills and digestive organs tissues and its content. Moreover, organisms such as teredinids grow up inside wood and this process could perhaps be related to creating growth space. All the endoglucanase extracts, from organs tissues and contents, showed maximum activity at 40 °C. The maximum activity was observed at pH 5.5 for all the extracts, except for intestine tissue, which maximum was at pH 6. Moreover, some of the extracts showed a different profile of the activity as a pH influence, suggesting different distribution of enzymes over the digestive system of the teredinids. The results suggested that the endo-β-1,4-glucanase from Teredinidae could be applied in process that requires low temperature, such as, simultaneous saccharification and fermentation, since it presents lower optimum temperature in comparison to enzymes from terrestrial microorganisms.     

Zinc and manganese bioavailability from human milk and infant formula used for very low birthweight infants,evaluated in a rat pup model

The bioavailability of zinc and manganese from diets used for very low birthweight infants was investigated in a rat pup model using radioisotopes. The effect of protein source and content and of pasteurization was evaluated, and two different approaches for evaluation of zinc and manganese bioavailability in the rat pup model were compared. Zinc and manganese bioavailability from the studied human milk and infant formula for very low birthweight infants was high. Liver uptake of⁶⁵Zn from labeled premature infant diets in sucklings rat pups was 26–29%, and absorption calculated as the difference between administered dose and nonabsorbed activity 6 h after oral intubation was 93–95%. Retention of manganese calculated as the sum of⁵⁴Mn retained by organs and carcass was 85–95% from human milk and premature infant formula and absorption calculated from nonabsorbed activity was 83–88% after 6 h. Fortification of early human milk significantly increased the bioavailability of zinc. No effect of pasteurization of human milk was found on zinc or manganese bioavailability. Liver zinc uptake was found to be a more sensitive parameter than absorption for evaluation of diets with a high zinc bioavailability. Measurement of retained activity of manganese in carcass and organs was judged to be the preferred parameter for evaluation of diets with high manganese availability.     

Differences in Activities of the Enzymes Of Nucleotide Metabolism and its Implications for Cardiac Xenotransplantation

Xenotransplantation is one be possible solution for a severe shortage of human organs available for transplantation. However, only a few studies addressed metabolic compatibility of transplanted animal organs. Our aim was to compare activities of adenosine metabolizing enzymes in the heart of different species that are relevant to clinical or experimental xenotransplantation. We noted fundamental differences: ecto-5′nucleotidease (E5′N) activity was 4-fold lower in pig and baboon hearts compared to the human hearts while mouse activity was compatible with human and rat activity was three times higher than human. There also were significant differences in AMP-deaminase (AMPD), adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities. We conclude that differences in nucleotide metabolism may contribute to organ dysfunction after xenotransplantation.     

Differences in activities of the enzymes of nucleotide metabolism and its implications for cardiac xenotransplantation

Xenotransplantation is one be possible solution for a severe shortage of human organs available for transplantation. However, only a few studies addressed metabolic compatibility of transplanted animal organs. Our aim was to compare activities of adenosine metabolizing enzymes in the heart of different species that are relevant to clinical or experimental xenotransplantation. We noted fundamental differences: ecto-5' nucleotidease (E5' N) activity was 4-fold lower in pig and baboon hearts compared to the human hearts while mouse activity was compatible with human and rat activity was three times higher than human. There also were significant differences in AMP-deaminase (AMPD), adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities. We conclude that differences in nucleotide metabolism may contribute to organ dysfunction after xenotransplantation.     

Antibacterial activity in Strongylocentrotus droebachiensis (Echinoidea), Cucumaria frondosa (Holothuroidea), and Asterias rubens (Asteroidea)

A search for antibacterial activity in different body parts of the green sea urchin Strongylocentrotus droebachiensis, the common starfish Asterias rubens, and the sea cucumber Cucumaria frondosa was conducted. Antibacterial activity was detected in extracts from several tissues in all species tested, but mainly in the coelomocyte and body wall extracts. Relatively high antibacterial activity could also be detected in gastrointestinal organs and eggs from A. rubens and in eggs from C. frondosa. Differences between active extracts regarding hydrophobicity and sensitivity to heat and proteinase K treatment indicated that several different compounds were responsible for the antibacterial activities detected. Lysozyme-like activity could be detected in several tissues from A. rubens. Haemolytic activity could be detected in all species tested, especially in the body wall extracts. Results from the current study suggest that marine echinoderms are a potential source for the discovery of novel antibiotics.     

Organ Specificity of Isoforms of Starch Branching Enzyme (Q-Enzyme) in Rice

The activity and isoenzymes of starch branching enzyme or Q-enzymein the developing endosperm were compared with those in theleaf blade, leaf sheath, culm and root of rice plants. Q-enzymefrom each of these organs could be resolved into two fractions,QE I and QE II, by column chromatography on DEAE cellulose.However, the ratio of the activity of QE I to that of QE IIvaried considerably among the organs. The Q-enzyme from theendosperm was specific for that organ in that the enzyme activity,on the basis of either fresh weight or soluble protein content,was about 100- to 1,000-fold higher than those from the otherorgans. Moreover, in the endosperm, the activity of QE I wasmarkably higher than that of QE II as compared with the relativelevels in other organs. Native polyacrylamide gel electrophoresisfollowed by activity staining revealed that the QE II fractionwas composed of multiple isoforms. The endosperm contained twoisoforms, QE IIa and QE IIb. After electrophoresis on a nativepolyacrylamide gel, QE IIa was detected only in the extractof endosperm, whereas QE IIb was present in extract of all organsexamined. The antiserum raised against QE IIa from the endospermcross-reacted to a considerable extent with QE IIb from thesame organ. However, the antiserum failed to recognize any isoformsof QE II from the other organs. ¹ Present address: National Institute of Sericultural and EntomologicalScience, Tsukuba, Ibaraki, 305 Japan.     

Immunohistochemical detection of betaine-homocysteine S-methyltransferase in human, pig, and rat liver and kidney

Betaine-homocysteine S-methyltransferase (BHMT) has been shown to be expressed at high levels in the livers of all vertebrate species tested. It has also been shown to be abundant in primate and pig kidney but notably very low in rat kidney and essentially absent from the other major organs of monogastric animals. We recently showed by enzyme activity and Western analysis that pig kidney BHMT was only expressed in the cortex and was absent from the medulla. Using immunohistochemical detection, we report here that in human, pig, and rat kidney, BHMT is expressed in the proximal tubules of the cortex. Immunohistochemical staining for BHMT in human, pig, and rat liver indicate high expression in hepatocytes. The staining patterns are consistent with cytosolic expression in both organs.     

Antitumor activity of diethynylfluorene derivatives of gold(I)

A list of diethynylfluorenes and their gold(I) derivatives have been studied for their antitumor activity as a function of their structure–activity relationships. End-capping the fluoren-9-one unit with gold(I) moieties could significantly strengthen the cytotoxic activity in vitro on three human cancer cell lines with induction of reactive oxygen species generation on Hep3B hepatocellular carcinoma cells and exhibit attractive antitumor activity from in vivo nude mice Hep3B xenograft model with limited adverse effects on vital organs including liver and kidney.     

人α-半乳糖苷酶转导克服异种移植HAR的小鼠实验研究

α 半乳糖苷酶可以特异地清除半乳糖α 1,3 半乳糖抗原 (Galα1,3Galantigen) ,此抗原是引起异种器官移植超急性排斥反应 (HyperacuteRejection ,HAR)的主要异种抗原 .将构建好的α半乳糖苷酶转基因载体通过显微注射的方式注入小鼠受精卵 ,培育出了转基因小鼠 .结果表明 ,转基因小鼠的心、肝、肾、脾、肺组织中均有人α 半乳糖苷酶基因的表达 ,其表达可以有效减少小鼠器官表面Galα1,3Gal抗原的表达水平 ,可以降低转基因小鼠脾细胞对补体介导的杀伤作用的敏感性 .研究表明人源α半乳糖苷酶基因可用于研制不表达Galα1,3Gal抗原的转基因动物 ,从而可以降低异种器官移植HAR的反应强度 ,提高移植物的存活期     

TohpreproHypSys- A Gene Expression and Defense Protein Activity in the Tobacco Wounding Response

Tobacco hydroxyproline-rich glycopeptide systemin precursor A (TobpreproHypSys-A), from which TobHypSys I and II are released, plays a crucial role in defense responses. Here, we investigated the expression otTobpreproHypSys- A and the activity of defense proteins in tobacco organs during wounding. Expression was induced more rapidly in upper, non-wounded leaves than in lower, wounded leaves. At 24 h after mechanical wounding, expression was tow in the roots, but increased in the stems and flowers, although to a lesser extent than in the leaves. At 3 or 10 d after insect-wounding, expression did not differ among organs, suggesting thatTobpreproHypSys- A could be induced globally and continuously throughout such stress. During that period, the activity of two defense proteins — PPO and PI — was consistent with the expression ofTobpreproHyp- Sys- A in various organs. This indicates that those proteins also could be regulated by TobHypSys, both globally and continuously.     

Indole-3-Pyruvic Acid as an Intermediate in the Conversion of Tryptophan to Indole-3-Acetic Acid. II. Distribution of Tryptophan Transaminase Activity in Plants

Extracts from different organs of 30 plant species belonging to 16 families have been analysed for tryptophan transaminase activity. Only the brown alga Fucus spiralis was found to be devoid of the enzymes. Among the other plants tested, a difference in activity of two orders of magnitude was recorded. None of the genera or families investigated could be considered as particularly rich or poor sources of the enzyme. Extracts from leaves and stem tips contained generally more transaminase activity than extracts from stems and roots. The results are discussed in relation to other reports on the occurrence of the enzyme in plants.     

Qualitative and quantitative distribution of plasminogen activators in organs from healthy adult mice

Twenty organs from healthy adult mice were tested for plasminogen activator activity. All were positive although specific activities varied 200-fold. Tissues with high activity were lung, uterus, brain and kidney. Endocrine glands were moderately rich in activator activity, and lymphoid tissues were poor. Molecular mass characterization was carried out. Two enzymatic forms were observed in all twenty organs: a 70 kDa form similar to human tissue plasminogen activator and a 48 kDa form analogous to mouse urokinase.