Arpad Pusztai

The importance of dietary polyamines in cell regeneration and growth

The polyamines putrescine, spermidine and spermine are essential for cell renewal and, therefore, are needed to keep the body healthy. It was previously believed that polyamines are synthesized by every cell in the body when required. However, in the present paper evidence is provided to show that, as in the case of the essential amino acids, the diet can supply sufficient amounts of polyamines to support cell renewal and growth. Systematic analysis of different foods was carried out and from the data obtained, the average daily polyamine consumption of British adults was calculated to be in the range 350-500 mumol/person per d. The major sources of putrescine were fruit, cheese and non-green vegetables. All foods contributed similar amounts of spermidine to the diet, although levels were generally higher in green vegetables. Meat was the richest source of spermine. However, only a part of the polyamines supplied by the diet is available for use by the body. Based on experiments with rats it was established that polyamines were readily taken up from the gut lumen, probably by passive diffusion, and were partly metabolized during the process of absorption. More than 80% of the putrescine was converted to other polyamines and non-polyamine metabolites, mostly to amino acids. The enzyme responsible for controlling the bioavailability of putrescine was diamine oxidase (EC 1.4.3.6). For spermidine and spermine, however, about 70-80% of the intragastrically intubated dose remained in the original form. Considering the limitations on bioavailability (metabolism and conversion), the amounts of polyamines supplied by the average daily diet in Britain should satisfy metabolic requirements.

Relationship between survival and binding of plant lectins during small intestinal passage and their effectiveness as growth factors

The effects on the small intestine and the growth of rats of six pure plant lectins: PHA (Phaseolus vulgaris); SBL (Glycine maxima); SNA-I and SNA-II (Sambucus nigra); GNA (Galanthus nivalis) and VFL (Vicia faba), covering most sugar specificities found in nature, were studied in vivo. Variable amounts, 25% (VFL) to 100% (PHA, GNA) of the lectins administered intragastrically, remained in immunochemically intact form in the small intestine after 1 h. All lectins, except GNA, showed binding to the brush border on first exposure, although this was slight with VFL. Thus, binding to the gut wall was not obligatory for resistance to proteolysis. Exposure of rats to lectins, except VFL, for 10 days, retarded their growth but induced hyperplastic growth of their small intestine. The two activities were directly related. PHA and SNA-II, whose intestinal binding and endocytosis was appreciable after 10 days of feeding the rats with diets containing these lectins and similar to that found on acute (1 h) exposure, were powerful growth factors for the small intestine. GNA, which did not bind at the start but was reactive after 10 days, and SNA-I, which behaved in the opposite way, induced changes in receptor expression in the gut. As they were bound to the brush border transiently, they were less effective growth factors. VFL was not bound or endocytosed, was non-toxic and did not promote gut growth.

Polyamines in food-implications for growth and health

Abstract Different types of food (fruits, vegetables, meat, and milk products) were analyzed by high pressure liquid chromatography to determine their polyamine (putrescine, spermidine, and spermine) contents. All foods contained some polyamines, although the concentrations in different individual food components were variable. As was established earlier using 14C-labeled putrescine, spermidine, and spermine, polyamines are readily taken up by the gut and enter the systemic circulation. Food appears to constitute a major source of polyamines for humans and animals. The distribution of polyamines in the body, as determined by measuring the accumulation of 14C-spermidine in different tissues of the rat, was correlated with the metabolic activity and growth of particular organs. Thus, phytohemagglutinin induced both extensive hyperplastic growth and the preferential accumulation of labeled spermidine in the gut. Correspondingly, when skeletal muscle growth was promoted by the β-antagonist, clenbuterol, 14C-spermidine was sequestered by the hind leg gastrocnemius muscle. It is concluded that food polyamines are not only necessary for normal body metabolism, but are also used and directed preferentially to tissues and organs that have been stimulated to grow by metabolic signals.

Antinutritive effects of wheat-germ agglutinin and other N-acetylglucosamine-specific lectins

Incorporation of N-acetylglucosamine-specific agglutinins from wheat germ (Triticum aestivum; WGA), thorn apple (Datura stramonium) or nettle (Urtica dioica) rhizomes in the diet at the level of 7 g/kg reduced the apparent digestibility and utilization of dietary proteins and the growth of rats, with WGA being the most damaging. As a result of their binding and endocytosis by the epithelial cells of the small intestine, all three lectins were growth factors for the gut and interfered with its metabolism and function to varying degrees. WGA was particularly effective; it induced extensive polyamine-dependent hyperplastic and hypertrophic growth of the small bowel by increasing its content of proteins, RNA and DNA. Furthermore, an appreciable portion of the endocytosed WGA was transported across the gut wall into the systemic circulation, where it was deposited in the walls of the blood and lymphatic vessels. WGA also induced the hypertrophic growth of the pancreas and caused thymus atrophy. Although the transfer of the gene of WGA into crop plants has been advocated to increase their insect resistance, as the presence of this lectin in the diet may harm higher animals at the concentrations required to be effective against most pests, its use in plants as natural insecticide is not without health risks for man.

Validation of dietary history method in a group of elderly women using measurements of total energy expenditure

The objective of the present study was to validate energy intake data, obtained by dietary history, in twelve elderly women aged 69–82 years. Energy and protein intakes were obtained using the dietary history method with a reference period of 30 d. Reported energy intake was compared with total energy expenditure (TEE) measured on two consecutive days in a respiration chamber. Reported protein intake was compared with mean N excretion from four 24 h urine collections. Mean reported energy intake was 7.2 (SD 1.5) MJ/d which was lower than TEE (P=0.059). Reported protein intake was 64 (SD 13) g/d and lower than estimated protein intake (P=0.053). The percentage underestimation was not related to body weight or percentage body fat. Subjects with a relatively high TEE or a relatively high estimated protein intake underestimated their energy intake to a greater extent. The discrepancy between reported energy intake and TEE was positively associated with the discrepancy between reported and estimated protein intakes. The results of this present study show an underestimation of energy intake of about 12% when using the dietary history method. Physical activity diaries completed in the chamber and during 4 d at home, as well as pedometer counts, indicated a higher level of physical activity in the free-living situation compared with the chamber situation. This suggests that the actual underestimation of energy intake may be even higher in this group of elderly women. These results have implications for the use of the dietary history method in, for example, epidemiological studies carried out in elderly subjects.

Lectins : biomedical perspectives

1. Lectins and Pathology : An Overview 2. Carrier-immobilized Carbohydrate Ligands: Design of the Lectin-detecting Tools and their Applications with Focus on Histopatholgy 3. Lectins, Microglia and Alzheimers Disease 4. The Role of Galectin-3 in Inflammation 5. The Role of Galectin-3 in Tumor Metastasis 6. Laminin-binding Lectins during Cancer Invasion and Metastasis 7. Lectins as Diagnostic Tools and Endogenous Targets in AIDS and Prion Diseases 8. Protein-carbohydrate Interactions in the Attachement of Enterotoxigenic Escherichia Coli to the Intestinal Mucosa 9. Lectin-carbohydrate Interactions in Bacterial Pathogenesis 10. Lectin-Mediated Interaction of Parasites with Host Cells

Glycoprotein II The Isolation and Characterization of a Major Antigenic and Non-Haemagglutinating Glycoprotein from Phaseolus Vulgaris

Summary 1. The isolation of Glycoprotein II from the seeds of kidney bean is described. The purification was achieved by extraction of the pH 5 insoluble proteins of the seeds at pH 8.3 followed by high-voltage electrophoresis and chromatography on Sephadex G-200 and DEAE-cellulose columns of the soluble proteins. 2. Glycoprotein II was found to be in the form of a monomer and essentially homogeneous at neutral and slightly alkaline pH values by disc gel electrophoresis, immuno-diffusion and -electrophoresis, velocity and equilibrium ultracentrifugation. Its monomer molecular weight was 140 000 ± 2000. Its hydrodynamic properties indicated a voluminous and asymmetric (β = 2.56 · 10−6; ve = 5.72 · 10−18 ml) particle with large amounts of entrained solvent. Between pH 3.4 and 6.6 it was mainly in the form of a tetramer (molecular weight of about 560 000) with smaller amounts of monomer and higher oligomers also present. These oligomers were found not to be in a rapid chemical equilibrium and their conversion rates were infinitely slow at these pH values. Between pH 2.2 and 3.4 the glycoprotein was almost exclusively in the form of the monomer. 3. Glycoprotein II was also shown to be homogeneous by chromatography and velocity and equilibrium ultracentrifugation in dissociating media. It was however dissociated to about one quarter (35 000–43 000) of the monomer molecular weight in these solvents. 4. The carbohydrate part was mainly composed of D-mannose and D-glucosamine. No uronic acids were present. The amino acid analyses revealed a definite deficiency in the sulphur-containing amino acids, especially in cyst(e)ine. Phosphorus-containing compounds were shown to be absent. 5. Glycoprotein II was found to be a strongly antigenic protein. It had however no haemagglutinating activity for rabbit erythrocytes.

Tomato lectin resists digestion in the mammalian alimentary canal and binds to intestinal villi without deleterious effects

Tomato lectin Dietary lectin Villus structure Rat intestine Human intestine

A survey of the nutritional and haemagglutination properties of legume seeds generally available in the UK

Eighty-five samples from fifteen different legume seed lines generally available in the UK were examined by measurements of their net protein utilization by rats and by haemagglutination tests with erythrocytes from a number of different animal species. From these results the seeds were classified into four broad groups. Group a seeds from most varieties of kidney (Phaseolus vulgaris), runner (Phaseolus coccineus) and tepary (Phaseolus acutifolius) beans showed high reactivity with all cell types and were also highly toxic. Group b, which contained seeds from lima or butter beans (Phaseolus lunatus) and winged bean (Psophocarpus tetragonolobus), agglutinated only human and pronase-treated rat erythrocytes. These seeds did not support proper growth of the rats although the animals survived the 10 d experimental period. Group c consisted of seeds from lentils (Lens culinaris), peas (Pisum sativum), chick-peas (Cicer arietinum), blackeyed peas (Vigna sinensis), pigeon peas (Cajanus cajan), mung beans (Phaseolus aureus), field or broad beans (Vicia faba) and aduki beans (Phaseolus angularis). These generally had low reactivity with all cells and were non-toxic. Group d, represented by soya (Glycine max) and pinto (Phaseolus vulgaris) beans, generally had low reactivity with all cells but caused growth depression at certain dietary concentrations. This growth depression was probably mainly due to antinutritional factors other than lectins. Lectins from group a seeds showed many structural and immunological similarities. However the subunit composition of the lectin from the tepary bean samples was different from that of the other bean lectins in this or any other groups.

Isolectins of Phaseolus vulgaris. A comprehensive study of fractionation

Abstract The results of fractionation studies and chemical, physical and immunochemical investigations established the existence of a range of closely related glycoproteins in the albumin fraction of the seeds of “haricot” kidney bean ( Phaseolus vulgaris ). The isoelectric point of these glycoproteins was found by isoelectric focusing to vary between about pH 4.5 and 6.9. Their subunit composition, however, was very similar; they were all made up of two types of subunits, 30 000 ± 1000 and 35 000 ± 1000, respectively, in a ratio of about 3:1. The chemical composition of these glycoproteins bore a close resemblance to each other. However, small differences were also found and these might have accounted for the charge heterogeneity. An immunochemically related glycoprotein was also found in the globulin fraction. This, however, was made up by subunits of the size of 30 000 ± 1000 and was different in amino acid composition. These glycoproteins were shown to be agglutinins, or isolectins, of red or white blood cells. They were also found to interact with other cells, such as far cells, and to be able to bind carbohydrate-type materials. However, these isolectins had negligible effects on lymphocyte transformation. The extent of all activities was strongly dependent on the isoelectric point of the isolectins. The specificity of the interaction, however, was apparently the same; i.e. they were all inhibited by the same compounds including N- acetyl- d -galactosamine and glycopeptides containing N- acetyl- d -glucosamine , mannose and galactose and obtained from fetuin. The possible involvement of these isolectins in bean toxicity is discussed.