Protein organization in the matrix of leaf peroxisomes. A multi-enzyme complex involved in photorespiratory metabolism.

This report is an investigation on how the compartmentation of peroxisomal metabolism, involved in the photorespiratory cycle, is accomplished. With isolated peroxisomes from spinach leaves the conversion of serine to glycerate, as coupled to the conversion of glycolate to glycine, was measured. Not only with intact but also with osmotically shocked peroxisomes, which had retained the aggregated state of the peroxisomal matrix but lost the integrity of the boundary membrane, the rates of glycerate synthesis were as high as required for the photorespiratory cycle in vivo.

The beta subunit of tomato fruit polygalacturonase isoenzyme 1: isolation, characterization, and identification of unique structural features.

We have purified and isolated cDNAs encoding the beta subunit of tomato fruit polygalacturonase isoenzyme 1 (PG1), a cell wall protein that associates with, and apparently regulates, the catalytic PG2 polypeptides. Expression of the beta subunit is fruit specific and temporally separated from the expression of PG2 during fruit development. The 37- to 39-kD beta subunit is encoded as a 69-kD precursor protein containing a signal sequence and two propeptide domains.

Expression of a Brassica napus Malate Synthase Gene in Transgenic Tomato Plants during the Transition from Late Embryogeny to Germination.

To study gene regulation during the transition from late embryogeny to germination, we have analyzed the expression of a gene encoding the glyoxylate cycle enzyme malate synthase in transgenic tomato (Lycopersicon esculentum) plants. We have shown that although there are at least four classes of malate synthase genes in Brassica napus L., one gene is expressed at a high level during both late embryogeny and postgermination.

Compartmentation studies on spinach leaf peroxisomes : evidence for channeling of photorespiratory metabolites in peroxisomes devoid of intact boundary membrane.

In concurrence with earlier results, the following enzymes showed latency in intact spinach (Spinacia oleracea L.) leaf peroxisomes: malate dehydrogenase (89%), hydroxypyruvate reductase (85%), serine glyoxylate aminotransferase (75%), glutamate glyoxylate aminotransferase (41%), and catalase (70%). In contrast, glycolate oxidase was not latent.

Spatial patterns of gene expression in Brassica napus seedlings: identification of a cortex-specific gene and localization of mRNAs encoding isocitrate lyase and a polypeptide homologous to proteinases.

We investigated the spatial expression of three genes that are expressed during seed germination and postgerminative development in Brassica napus L. using in situ hybridization procedures. Two of the mRNAs encode isocitrate lyase and a predicted polypeptide that is homologous to cysteine proteinases.

Sterol composition and biosynthesis in sorghum: Importance to developmental regulation.

Sterol composition and biosynthesis have been examined in seeds, germinating seeds and blades from fally matured leaves ofSorghum bicolor in various stages of development'from seedlings (seven-day plants) to flowering (66-day) plants. The profile of the dominant free sterols of seeds was similar to that of leaf blades; both contained cholesterol, 24α-methylcholesterol (campesterol), 24β-methylcholesterol (dihydrobrassicasterol), 24α-ethylcholesterol (sitosterol) and 24α-ethylcholesta-5,22-dienol (stigmasterol). Sufficient sterol intermediates were identified in the plant to indicate separate post-cycloartenol pathways to sterolic end products.

Physiological requirement for biosynthesis of multiple 24 beta-methyl sterols in Gibberella fujikuroi.

Studies with Gibberella fujikuroi have been designed to examine the relationship between the biosynthesis and function of fungal sterols. Evidence was obtained through appropriate feeding and trapping experiments for the existence of multiple end products which are produced by separate routes in the later stages of sterol biosynthesis. The three end products, ergosterol (24 beta-methylcholesta-5,7,22E-trien-3 beta-ol), brassicasterol (24 beta-methylcholesta-5,22E-dien-3 beta-ol), and 22(23)-dihydrobrassicasterol (24 beta-methyl-cholesterol), were found to be non-interconvertible during logarithmic phase growth; thus the metabolic route delta 5,7,22-24 beta-CH3----delta 5,22-24 beta-CH3----delta 5-24 beta-CH3 was ruled out.

[Patellar changes during long-term observations on the Blauth knee joint endoprosthesis].

Changes in the position and structure of the patella and their importance with regard to pain patterns are described on the basis of long-term observation of the Blauth prosthesis. Examinations were performed on 206 knee prostheses on average 37.6 months (min.