Increased Polyamine Concentrations in the Urine of Human Cancer Patients

WE have found that patients with various types of solid tumours and leukaemias have considerably increased concentrations of the polyamines such as putrescine (diaminobutane), spermidine and spermine in their urine. Polyamines are small cationic substances, which occur ubiquitously in nature¹. Because enhanced polyamine synthesis and accumulation are characteristic of rapid growth systems^2–6 it seemed possible that they might serve as indicators of rapidly proliferating tumours.     

Photomorphogenesis, Photosynthesis, and Early Growth of Primary Leaves of Phaseolus vulgaris

The response of leaf tissue to white, blue, red, and far-redlight has been examined. Leaves on plants grown in darknessshow increased cell number, cell volume, and area when exposedto long periods (up to 48 h) of low-intensity red, blue, orfar-red radiation. This is believed to be a photomorphogenicresponse which does not involve photosynthesis. Leaves fromplants exposed to white light during germination do not usuallyrespond to red, blue, or far-red light. An exception to thiswas found for leaf discs which showed a larger increase in areathan the dark controls following exposure to far-red light for24 h. Leaf tissue from light-grown plants responds to high-intensitywhite light, probably through photosynthesis. Discs cut fromdark-grown plants and cultured in white light grow equally wellin air and CO₂-free conditions. Application of the photosyntheticinhibitor DCMU reduces growth and chlorophyll formation, however. It is concluded that light, perhaps acting through the phytochromemechanism, has initially a number of morphogenic effects includinginitiation of development of the photosynthetic apparatus. Theresponses to photomorphogenically active radiation do not persistand light effects through photosynthesis are rapidly initiatedand dominate the later stages of leaf growth.     

Identification of an Apically-Located Antigen That Is Conserved in Sporozoan Parasites

ABSTRACT. Sporozoan parasites of the phylum Apicomplexa all possess common apical structures. The current study used a monoclonal antibody (mAb-E12) to identify a conserved antigen in the apical region of merozoites of seven species of Plasmodium (including rodent, primate and human pathogens), tachyzoites of Toxoplasma gondii , bradyzoites of Sarcocystis bovis , and sporozoites and merozoites of Eimeria tenella and E. acervulina. The antigen was also present in sporozoites of haemosporinid parasites. Immunofluorescence studies showed that the antigen was restricted to the apical 3rd of these invasive stages. Using immunoelectron microscopy, labeling was demonstrated in the region of the polar ring, below the paired inner membranes of the parasite pellicle, and near the subpellicular microtubules radiating from the polar ring of merozoites and sporozoites of E. tenella . The majority of the antigen could be extracted with 1% Triton-X 100, but a portion remained associated with the cytoskeletal elements. The molecule has a relative rate of migration (M_r) of 47,000 in Plasmodium spp. and 43–46,000 in coccidian species. Since the epitope recognized by mAb-El 2 is highly conserved, restricted to motile stages, and appears to be associated with microtubules, this antigen could be involved in cellular motility and cellular invasion.     

Characterization of SSRs from the American lobster,Homarus americanus

The American lobster (Homarus americanus), a commercially important benthic marine crustacean, is widely distributed along the continental shelf of the western North Atlantic. The population substructure of this species remains poorly understood despite its economic value. Informative markers are required to clarify relationships between local populations. To this end, we developed eight polymorphic short sequence repeats (SSR) for the American lobster, which were derived from expressed sequence tags. Additionally, we tested four SSRs previously identified for the Norway lobster (Nephrops norvegicus L.) for cross‐species utility; only one of these showed polymorphism.     

Characteristics of the population build-up of the Russian wheat aphid Diuraphis noxia and the effect on wheat yield in the eastern Orange Free State

Diuraphis noxia infestations were monitored in early winter and winter wheat during 1983–1985. The aphid population increase was logarithmic in all three years and on both cultivars 100 % infestation levels were recorded. The period of exponential increase in both percentage infestation and in the number of D. noxia per stem took place when the plants had reached the stem elongation stage. The mean number recorded at peak population levels was 150–160 aphids per stem. During the period of plant senescence numbers dropped rapidly. Large reductions in yield were recorded on all infested plants. Single-plant data showed that yield reductions in the early winter cv. Betta were related to the duration of infestation. Relative to sprayed controls, reduction in kernel mass ranged from 25–80% and in 1000-kernel mass from 15–45%. However, the yield reductions of the faster-growing cv. Flamink, appeared to be dependent on the number of aphids per plant during the later growth stages and not the duration of infestation.     

Fitness consequences of potential assortative mating inside and outside a hybrid zone in Chorthippus parallelus (Orthoptera: Acrididae): implications for reinforcement and sexual selection theory

We have examined the fitness consequences of random and potentially non-random matings within two populations taken from inside, and two from outside a hybrid zone in Chorthippus parallelus. When given the opportunity to mate non-randomly, females from all populations laid egg pods more quickly than females obliged to mate at random. A range of fitness parameters measured on the offspring did not show increased fitness following potential non-random mating for any population. However, in non-hybrid populations, the sons of non-randomly mated females had about twice the mating success of the sons of those females forced to mate at random, suggesting the existence of heritable variation for male reproductive success. Hybrid dysfunction did not occur amongst the offspring of randomly mated hybrid females, demonstrating that the lack of dysfunction within these populations is not due to the evolution of assortative mating within them.     

The Location of Cytokinins and Gibberellins in Wheat Seeds

Wheat seeds (Triticum aestivum L. cvs. Yorkstar and Sirius) were cut transversely into embryoless and embryo-containing (embryonated) halves and the content of endogenous cytokinins and gibberellins in both halves determined before and after the seeds imbibed water for 12–15 h at 22°C in the light. Dry seeds contained little ethyl acetate-extractable gibberellin activity as measured by bioassay but n-butanol-soluble cytokinins were detected mainly in the embryoless halves. Dry, embryonated half-seeds contained water-soluble gibberellins which could be extracted into acidic ethyl acetate after treatment of the aqueous extract with either alkaline phosphatase, β-glucosidase or a crude pectolytic enzyme preparation. When half-seeds were allowed to imbibe water for 12 h and then extracted, cytokinin activity was largely lost from the embryoless halves and completely from the embryonated halves and water-soluble gibberellins were also lost from the embryonated halves. However, ethyl acetate-soluble gibberellins were present in the latter suggesting that “bound’ gibberellins were released during imbibition. The hormones present in normal and naturally embryoless dry grains of cv. Yorkstar were also determined. Both gibberellin and cytokinin activity was higher in normal grains suggesting that the presence of an embryo is essential for synthesis or accumulation of these hormones in the grain during development.     

D- AND L-STEREOISOMERS OF ALLYLGLYCINE: CONVULSIVE ACTION AND INHIBITION OF BRAIN L-GLUTAMATE DECARBOXYLASE

DL-Allylglycine was resolved into the L- and D-stereoisomers using hog kidney acylase. Both isomers were active as convulsants after administration to mice. The dose of D-allylglycine required to induce convulsions was greater than that of the L-isomer. Studies on the concentration of the two isomers in brain suggest that the lower effectiveness of D-allylglycine is partially due to its slower penetration into the brain through the blood-brain barrier. Both isomers of allylglycine inhibited brain glutamate decarboxylase in vitro to approximately the same extent, however, in vivo L-allylglycine inhibited the enzyme more strongly than the D isomer. Concentrations of allylglycine which caused a significant inhibition of L-glutamate decarboxylase in vivo were ineffective in inhibiting the enzyme in vitro. Oxidation products derived from L- or D-allylglycine by the action of either L- or D-amino acid oxidase caused an almost complete inhibition of the enzyme in vitro. It is suggested that a common intermediate derived from the two isomers (possibly 2-keto-4-pentenoic acid) is responsible for the in vivo inhibition of L-glutamate decarboxylase and possibly also for the induction of convulsions.