To permit an assessment of the relative contributions of the transsulfuration and the direct sulfhydration pathways for homocysteine biosynthesis, the time course of incorporation of (35)S from (35)SO(4) (2-) into various sulfur-containing compounds in Lemna paucicostata has been determined. Plants were grown with either low (4.5 micromolar) or ample (1,000 micromolar) sulfate in the medium. At...

Cell-free extracts from Lemna and suspension cultured carrot (Daucus Carota L.) catalyze S-adenosylmethionine-dependent N-methylations of phosphoethanolamine, phosphomethylethanolamine, and phosphodimethylethanolamine; extracts of suspension cultured soybean (Glycine max), of phosphoethanolamine only. Material pelleted from each tissue between 15,000 and 100,000g catalyzes S-adenosylmethionine-...

Accumulation of (14)C-labeled glycine and microelectrode techniques were employed to study glycine transport and the effect of glycine on the membrane potential (Deltapsi) in Lemna gibba G1. Evidence is presented that two processes, a passive uptake by diffusion and a carrier-mediated uptake, are involved in glycine transport into Lemna cells. At the onset of active glycine uptake the component...

We have characterized a DNA-binding activity, designated light-regulated nuclear factor (LRF-l), which interacted with a specific sequence located 150 nucleotides upstream from the transcription start site of a phytochromeregulated Lemna gibba rbcS gene (SSUSS). There was a higher level of LRF-1 activity recovered from nuclei of light-grown plants than from dark-treated plants. In light-grown p...

Lemna perpusilla 6746, grown photoautotrophically at a series of sulfate concentrations ranging from 0.32 to 1,000 mum, was labeled to radioisotopic equilibrium with (35)SO(4) (2-). Sulfur-containing compounds were isolated and purified from the colonies. Radioactivity in each compound was a measure of the amount of that compound present in the tissue. The following compounds were identified an...

Tests aiming to determine the toxic properties of compounds discharged into aquatic systems have relied more on fish or invertebrates than on primary producers and among a number of producers; algae are the most popular test organisms. Macrophytes are important ecological elements in freshwaters and are therefore potentially key organisms for use in toxicity testing of compounds suspected of ac...

In the current study, the stem wood of Millettia ovalifolia was evaluated for antifungal, insecticidal and phytotoxic activities. The results revealed that all the fractions showed no antibacterial activity against the tested bacterial strains. In case of antifungal activity, only ethyl acetate (EA) and chloroform (C) fractions exhibited minimum inhibitory concentration both at 500 μg/ml agains...

We have characterized a DNA-binding activity, designated light-regulated nuclear factor (LRF-1), which interacted with a specific sequence located 150 nucleotides upstream from the transcription start site of a phytochrome-regulated Lemna gibba rbcS gene (SSU5B). There was a higher level of LRF-1 activity recovered from nuclei of light-grown plants than from dark-treated plants. In light-grown ...

Nearly 230 species of biting midges have been recorded or described from Argentina; 38 of them are known from the Buenos Aires province and only one is cited from Martín García Island. This paper presents the results raised from six collecting trips which took place on the island during spring 2005, summer 2006 and autumn 2009. Diverse sampling sites including permanent and temporary aquatic en...