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At least 163 records · Page 9Linked to original sources
PubMed1982

Post-embedding immunolabelling. Some effects of tissue preparation on the antigenicity of plant proteins.

The sensitivity of detection of proteins by immunolabelling embedded and sectioned material depends upon retention of antigenicity during tissue processing. Losses in pea seed storage protein antigenicity have been assessed using a solid phase radioimmunoassay. Storage proteins adsorbed to wells of microtiter plates were treated with the various "tissue preparation" steps and reacted with 125I-antibodies to the storage proteins. The glutaraldehyde or formaldehyde fixation steps caused approximately 60% and 30% loss in antigenicity, respectively. With each subsequent preparative step, losses accumulate and following treatment with Spurr's epoxy resin reached approximately 85% and 90%, respectively. However, if Lowicryl K4M, a methacrylate-acrylate embedding medium was used, losses were retained at approximately 70% and 60%, respectively. These observations have been verified on sections of embedded material using two labelling procedures, with protein A-gold and ferritin as the markers.

Cytological Techniques↗
PubMed2000

Effects of animal or plant protein diets on cecal fermentation in guinea pigs (Cavia porcellus), rats (Rattus norvegicus) and chicks (Gallus gallus domesticus).

Monogastric herbivores such as the guinea pig depend on energy supply from enteric fermentation as short-chain fatty acids (SCFA) corresponding to 30-40% of their maintenance energy requirements. They evolved specific digestive system to adapt their indigenous microflora to plant polysaccharides fermentation. No information has been available about the adaptability of microbial fermentation in hindgut of the monogastric herbivorous to an animal protein diet. We investigated if the guinea pig can fully retrieve energy of an animal protein diet by hindgut fermentation compared with a plant protein diet. For comparison, we also studied two omnivores. End products of in vitro cecal fermentation (SCFA, ammonia and gases) were measured to judge how well an animal protein diet could be fermented. The animal protein diet resulted in the less intensive fermentation with increased feed intake and volume of cecal contents than the plant protein diet only in guinea pigs. This may be due to a limited capacity of the hindgut microflora to adapt to the substrate rich in animal protein. We also found that chick cecal contents produced methane at higher emission rate than ruminants.

Animals↗
PubMed2002

The novel ethylene-regulated gene OsUsp1 from rice encodes a member of a plant protein family related to prokaryotic universal stress proteins.

Using subtractive hybridization a submergence-induced gene was identified from deepwater rice, OsUsp1, that encodes a homologue of the bacterial universal stress protein family. Sequence analysis revealed that OsUSP1 is most closely related to the bacterial MJ0577-type of ATP-binding USP proteins which have been suggested to act as a molecular switch. USP protein homologues appear to be ubiquitous in plants and are encoded by gene families, but are absent in animal species. In the youngest internode of deepwater rice plants, OsUsp1 expression was very strongly induced within 1 h of submergence. Elevated transcript levels were observed in dividing cells, in expanding cells and in differentiated tissue indicating that USP1 mediates a general process. Gene induction was shown to be regulated by ethylene with a highly similar expression pattern to that observed with submergence treatment. Based on sequence information and on expression data it is hypothesized that OsUSP1 plays a role in ethylene-mediated stress adaptation in rice.

Adenosine Triphosphate↗
PubMed2001

[Wheat gliadin nanoparticle size control by determination of the solubility parameters of these plant proteins].

Gliadins nanoparticles, protein complex from wheat gluten, were prepared by coacervation (macromolecules desolvatation). The objective was to prepare nanometric colloidal systems whith both smallest particle size and polidispersity index. Macromolecules solvent choice is predominant. Their total solvatation enables of control the desolvatation process and thence particle sizes. Different pharmaceutical solvents were assayed. In order to select the best of them, a thermodynamical approach was used. It rests on the determination of the solubility parameter delta G of the gliadins complex. The best solvent is the one whose solubility parameter (calculated or experimentally determined) is equal to the plant protein's.

Gliadin↗
PubMed1980

Effects of prostaglandin-F2 alpha and a plant protein "Trichosanthin", on 10-day pregnant rabbits.

The effect of Trichosanthin (TCS), a protein obtained from the roots of Trichosanthis kirilowii, alone or in combination with prostaglandin-F2 alpha (PGF2 alpha; Tromethamine salt) on the termination of pregnancy in rabbits was investigated. Intraperitoneal injection of 1 or 2 mg TCS/10-day pregnant rabbits neither altered the serum progesterone (delta 4P) level nor interrupted pregnancy. Doses of 0.5 or 0.25 mg PGF2 alpha incorporated in a Silastic-PVP tube and inserted intravaginally, terminated pregnancy within 72 h of treatment in 75 and 16% of the treated does, respectively. By contrast, does treated on day-10 of pregnancy with a combination of a non-effective dose of TCS (1 mg) and a sub-effective dose of PGF2 alpha (0.25 mg) terminated pregnancy in all the treated animals as no live embryos were found within 3 days of treatment. Pregnancy interruption was associated with a significant reduction of serum delta 4P and delta 4P/20 alpha-dihydroprogesterone (20 alpha-DHP) ratio. The present study indicates that TCS and PGF2 alpha act synergistically, rendering the termination of 10-day pregnancy possible in the rabbit. It was also noted that pregnancy cannot be maintained when the serum delta 4 P level drops below 4 ng/ml and delta 4P/20 alpha-DHP falls lower than 0.6 in the 10-day pregnant rabbit.

Abortifacient Agents↗
PubMed2006

Cloning and expression of two plant proteins: similar antimicrobial activity of native and recombinant form.

Antimicrobial peptides and proteins are being studied with increasing interest because of their broad range antimicrobial activity. Among plant antimicrobial proteins, the wheat seed polypeptides, puroindoline a and puroindoline b, are particularly interesting because of their established antibacterial activity. In this paper we describe different strategies used to clone His tagged and GST tagged puroindolines obtaining 1.5 mg recombinant protein from 1 l culture. The antimicrobial activity of recombinant and native puroindolines was comparable.

Anti-Bacterial Agents↗
PubMed1983

Functional properties of plant proteins. Part IV. Foaming properties of modified proteins from faba beans.

The foaming ability (foam capacity and stability) of protein isolates from faba beans (Vicia faba L.) depends closely on the manner of isolation and treatment of the isolates. Unmodified isolates possess a moderate foaming ability with a maximum foam capacity of 210% in alkaline solution (pH 10.0) at concentrations of about 3%. The foam capacity and stability can be improved by treatment with isopropanol or moderate temperature, as well as by denaturing by alkali or by specially heating at 80 degrees C. Thereby modified preparations are formed possessing a foam capacity of more than 400% and a foam stability of 80-100%. High concentrations of protein favour the formation of stable foams. Succinylation improves the foam formation properties of proteins. Maximum values of foam capacity (approximately equal to 400%) are produced at a high degree of succinylation, that is after blocking more than 80% of protein amino groups, in neutral solution, while the foam stability under these conditions decreases. Heating at 80 degrees C, high protein concentrations (10%) and a weak acidic milieu (pH 5.5) favour the formation of stable foams from succinylated proteins.

1-Propanol↗
PubMed2000

The broad bean nodulin VfENOD18 is a member of a novel family of plant proteins with homologies to the bacterial MJ0577 superfamily.

Full-length transcript sequences were isolated from broad bean root nodules, which encode a novel nodulin designated VfENOD18. The corresponding transcripts were detected in early and in late stages of nodule development and were localized exclusively in the nitrogen-fixing zone III. The VfENOD18 sequence is not only homologous to a number of ESTs from various mono- and dicotyledonous plants, but also to the ATP-binding protein MJ0577 from Methanococcus jannaschii and to a range of bacterial proteins that belong to the MJ0577 superfamily. Hence, VfENOD18 is a member of a ubiquitous family of plant proteins that might function as ATP-binding proteins or ATPases. On the genomic level, VfENOD18 genes can be divided into two groups on the basis of differences in their 5' UTRs. One group lacks the 5' UTR region including the ATG initiation codon, whereas the second group contained the complete 5' UTR region. Further upstream of this VfENOD18 gene, a retrotransposon sequence was identified. The -14/-964 VfENOD18 promoter fragment was devoid of complete organ-specific elements known from other nodulin gene promoters. Nevertheless, this region was able to mediate full promoter activity in the central region of transgenic Vicia hirsuta root nodules.

5' Untranslated Regions↗
PubMed1994

Cloning and biochemical characterization of a plant protein kinase that phosphorylates serine, threonine, and tyrosine.

Phosphorylation of proteins on serine, threonine, or tyrosine residues represents an important biochemical mechanism to regulate the activity of enzymes and is used in many cellular processes. In animals, protein serine/threonine and protein tyrosine kinases are known to perform essential roles in many pathways that transmit external stimuli from the cell surface to the cell inferior and the nucleus. In plants, although an increasing number of protein serine/threonine kinases have been cloned, the existence of protein tyrosine kinases remains yet to be demonstrated. Here, we report the cloning and biochemical characterization of a plant protein kinase, Arabidopsis dual specificity kinase 1 (ADK1), using a functional screening method, namely by screening an Arabidopsis expression library with antiphosphotyrosine antibodies. Four independent cDNA clones that define a polypeptide of 319 amino acids length with homology to protein kinases were identified in this screen. Phosphoamino acid analysis of the autophosphorylated kinase shows that ADK1 phosphorylates serine, threonine, and tyrosine. Using poly (Glu/Tyr) as a substrate, we confirm that ADK1 is capable of phosphorylating tyrosine residues.

Arabidopsis↗
PubMed1991

Circadian rhythms in the activity of a plant protein kinase.

Bryophyllum fedtschenkoi is a Crassulacean acid metabolism plant whose phosphoenolpyruvate carboxylase is regulated by reversible phosphorylation in response to a circadian rhythm. A partially purified protein kinase phosphorylated phosphoenolpyruvate carboxylase in vitro with a stoichiometry approaching one per subunit and caused a concomitant 5- to 10-fold decrease in the sensitivity of the carboxylase to inhibition by malate. The sites phosphorylated in vitro were identical to those phosphorylated in intact tissue. The activity of the protein kinase was controlled in a circadian fashion. During normal diurnal cycles, kinase activity appeared between 4 and 5 h after the onset of darkness and disappeared 2----3 h before the end of darkness. Kinase activity displayed circadian oscillations in constant environmental conditions. The activity of protein phosphatase 2A, which dephosphorylates phosphoenolpyruvate carboxylase, did not oscillate. Treatment of detached leaves with the protein synthesis inhibitors puromycin and cycloheximide blocked the nocturnal appearance of the protein kinase activity, maintained phosphoenolypyruvate carboxylase in the dephosphorylated state and blocked the circadian rhythms of CO2 output that is observed in constant darkness and CO2-free air. The simplest explanation of the data is that there is a circadian rhythm in the synthesis of phosphoenolpyruvate carboxylase kinase.

Circadian Rhythm↗
PubMed2006

Over-expression of SOB5 suggests the involvement of a novel plant protein in cytokinin-mediated development.

Cytokinins are a class of phytohormones that play a critical role in plant growth and development. sob5-D, an activation-tagging mutant, shows phenotypes typical of transgenic plants expressing the Agrobacterium tumefaciens isopentenyltransferase (ipt) gene that encodes the enzyme catalyzing the first step of cytokinin biosynthesis. The sob5-D mutant phenotypes are caused by over-expression of a novel gene, SOB5. Sequence analysis places SOB5 in a previously uncharacterized family of plant-specific proteins. A translational fusion between SOB5 and the green fluorescent protein reporter was localized in the cytoplasm as well as associated with the plasma membrane when transiently expressed in onion epidermal cells. Analysis of transgenic plants harboring an SOB5:SOB5-beta-glucuronidase (GUS) translational fusion under the control of the SOB5 promoter region showed GUS activity in vegetative tissues (hydathodes and trichomes of leaves, shoot meristems and roots) as well as in floral tissues (pistil tips, developing anthers and sepal vasculature). Cytokinin quantification analysis revealed that adult sob5-D plants accumulated higher levels of trans-zeatin riboside, trans-zeatin riboside monophosphate and isopentenyladenine 9-glucoside when compared to the wild-type. Consistent with this result, AtIPT3 and AtIPT7 were found to be up-regulated in a tissue-specific manner in sob5-D mutants. Physiological analysis of the sob5-D mutant demonstrated reduced responsiveness to exogenous cytokinin in both root-elongation and callus-formation assays. Taken together, our data suggest a role for the novel gene SOB5 in cytokinin-mediated plant development.

Alkyl and Aryl Transferases↗