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PubMed2003

Foreign gene products can be enhanced by introduction into low storage protein mutants.

Transgenic rice expressing soybean glycinin in its endosperm was crossed with two types of low-glutelin mutants to determine how much storage the protein mutants can contribute to increases in glycinin accumulation. The glycinin level (102 microg/100 mg seed) in the parental transgenic line was enhanced to approximately 224-237 microg/100 mg seed within a genetic background deficient in glutelin (i.e. of low glutelins). The enrichment of this foreign gene product was compensated by a decrease in the expression of other endogenous prolamine and globulin storage proteins, resulting in an almost equivalent total amount of seed storage proteins. These results show that low storage protein mutants can provide potentially useful hosts for the expression of foreign genes, allowing a higher-level accumulation, because they can provide wider space for the accumulation of foreign gene products than in the normal host plant.

Journal Article↗

PubMed1996

Definition of the initial immunologic modifications upon in vitro gliadin challenge in the small intestine of celiac patients.

BACKGROUND & AIMS: Mucosal cell-mediated immune response is considered the central event in the pathogenesis of celiac disease. In cultured intestinal explants from celiacs in remission, we have characterized the early stages of gliadin-induced immune activation. METHODS: Intestinal biopsy specimens (15 treated celiacs and 13 controls) were cultured with gliadin or maize prolamine digests for 24 hours as well as for 1, 2, 4, 6, 8, and 12 hours in some subjects. The expression of immunologic markers was detected by immunocytochemistry. RESULTS: Gliadin challenge may initiate two parallel pathways, one of which leads to T-cell activation and another that precedes it. Epithelial cells overexpress DR molecules after 1 hour, and in a second stage T lymphocytes become fully activated. Moreover, T lymphocytes migrate in the upper mucosal layers. T lymphocytes that migrate in the higher lamina propria compartments are mainly CD4+ and show markers of activation; migrating intraepithelial lymphocytes are CD8+ and do not express these markers. CONCLUSIONS: In vitro gliadin challenge is a suitable model to reproduce various immunologic features of celiac lesions; these may be caused by different pathways. The comprehension of these phenomena is essential to clarify the distinctive pathogenic mechanisms leading to disease and may help in defining novel therapeutic approaches.

CD3 Complex↗

PubMed2001

Current approaches to diagnosis and treatment of celiac disease: an evolving spectrum.

Celiac disease (CD) is a syndrome characterized by damage of the small intestinal mucosa caused by the gliadin fraction of wheat gluten and similar alcohol-soluble proteins (prolamines) of barley and rye in genetically susceptible subjects. The presence of gluten in these subjects leads to self-perpetuating mucosal damage, whereas elimination of gluten results in full mucosal recovery. The clinical manifestations of CD are protean in nature and vary markedly with the age of the patient, the duration and extent of disease, and the presence of extraintestinal pathologic conditions. In addition to the classical gastrointestinal form, a variety of other clinical manifestations of the disease have been described, including atypical and asymptomatic forms. Therefore, diagnosis of CD is extremely challenging and relies on a sensitive and specific algorithm that allows the identification of different manifestations of the disease. Serologic tests developed in the last decade provide a noninvasive tool to screen both individuals at risk for the disease and the general population. However, the current gold standard for the diagnosis of CD remains histologic confirmation of the intestinal damage in serologically positive individuals. The keystone treatment of CD patients is a lifelong elimination diet in which food products containing gluten are avoided.

Celiac Disease↗

PubMed2005

Limited efficiency of prolyl-endopeptidase in the detoxification of gliadin peptides in celiac disease.

BACKGROUND & AIMS: The resistance of prolamines to digestive enzymes is thought to be a key contributor to the pathogenesis of celiac disease by promoting the intestinal entrance of peptides able to trigger inflammation in at-risk individuals. Oral administration of a bacterial prolyl-endopeptidase (PEP) therefore was proposed as a treatment for celiac disease. To delineate the feasibility of this treatment, the effect of PEP on gliadin peptides was assessed in vitro, and ex vivo during their transport across intestinal biopsy specimens of active celiac disease patients. METHODS: In vitro degradation by PEP of 3H-labeled gliadin peptides 56-88 (33-mer) and 31-49, was analyzed by radio-reverse-phase high-performance liquid chromatography and mass spectrometry. For ex vivo studies, PEP and 3H-peptides were added together onto the mucosal side of duodenal biopsy specimens mounted in Ussing chambers, and peptide transport and digestion were assessed by radio-reverse-phase high-performance liquid chromatography. RESULTS: Gliadin peptides were degraded partly by 20 mU/mL PEP both in vitro and ex vivo. This concentration of PEP decreased the amount of intact peptides 31-49 and 56-88 crossing the intestinal biopsy specimens of celiac disease patients, but could not prevent the intestinal passage of toxic or immunostimulatory metabolites. PEP concentrations of at least 500 mU/mL for 3 hours were required to achieve full detoxification of peptides and to prevent intestinal transport of active fragments. CONCLUSIONS: After prolonged exposure to high concentrations of PEP, the amount of immunostimulatory gliadin peptides reaching the local immune system in celiac patients is decreased. These results provide a basis to establish whether such conditions are achievable in vivo.

Biopsy↗

PubMed1989

[Magnetic resonance tomographic studies of pancreatic transplants].

In a pilot study, a total of 16 recipients of a combined pancreatic-renal allograft were examined by means of magnetic resonance imaging. Two groups were formed according to the management of the exocrine secretion: In group I patients (n = 8) the pancreatic duct was occluded with an alcoholic prolamine solution, in group II (n = 8) pancreatic juice was diverted either into a Roux-loop of jejunum (IIa, n = 4) or into the urinary bladder (group IIb, n = 4). On the T1-weighted images no difference was found between both groups with respect to signal intensity. In contrast, on T2-weighted images of group IIb, which were in situ for a significantly shorter time, a higher signal intensity was noticed as compared with the other patients. From these findings it is concluded that graft fibrosis may occur even in pancreas transplants with diversion of the exocrine secretion.

Adult↗

PubMed1984

[A new material in neurosurgery].

A new alcoholic prolamine solution is now available (ETHIBLOC, supplied by Ethicon, Norderstedt) which can be used in neurosurgery for a variety of purposes. This material hardens quickly in an aqueous medium. Animal experiments have not shown any damaging action on the brain, meninges, or bone. The excellent tolerance of the material was seen in a total of 22 patients operated on with the help of Ethibloc. It is particularly well suited for closing frontal CSF fistulas, incised frontal sinuses, and for rearranging or shunting in case of cerebral vascular deformities. It can also be used as a carrier of antibiotics in osteomyelitis, for covering up minor defects of the dura mater, for dura sealing, and for closing the bone after trephination. The preparation is transformed completely to connective tissue within a period of 40 to 90 days. New techniques of surgery are described which have become possible by the use of Ethibloc.

Animals↗

PubMed1987

Improving the in vitro protein digestibility of sorghum with reducing agents.

We have shown in previous reports that cooked sorghum protein is less digestible than other cooked cereal proteins. The pepsin-indigestible proteins in sorghum were found to be mainly prolamin proteins. Cooking sorghum in the presence of 2-mercaptoethanol increased protein digestibility (in vitro with pepsin or trypsin/chymotrypsin) to a level comparable with other cereals. At a concentration of 100 mM, other reducing agents (dithiothreitol, sodium bisulfite, and L-cysteine) were equally effective in improving sorghum digestibility. When maize was cooked in the presence of 2-mercaptoethanol, protein digestibility increased 5% compared to 25% for sorghum. Cooking barley, rice, and wheat with 2-mercaptoethanol had no significant effect on protein digestibility. The addition of reducing agents appears to prevent the formation of protein polymers linked by disulfide bonds.

Journal Article↗

PubMed1997

Expression of a mutant alpha-zein creates the floury2 phenotype in transgenic maize.

The maize floury2 mutation results in the formation of a soft, starchy endosperm with a reduced amount of prolamin (zein) proteins and twice the lysine content of the wild type. The mutation is semidominant and is associated with small, irregularly shaped protein bodies, elevated levels of a 70-kDa chaperone in the endoplasmic reticulum, and a novel 24-kDa polypeptide in the zein fraction. The 24-kDa polypeptide is a precursor of a 22-kDa alpha-zein protein that is not properly processed. The defect is due to an alanine-to-valine substitution at the C-terminal position of the signal peptide, which causes the protein to be anchored to the endoplasmic reticulum. We postulated that the phenotype associated with the floury2 mutation is caused by the accumulation of the 24-kDa alpha-zein protein. To test this hypothesis, we created transgenic maize plants that produce the mutant protein. We found that endosperm in seeds of these plants manifests the floury2 phenotype, thereby confirming that the mutant alpha-zein is the molecular basis of this mutation.

Gene Expression↗

PubMed1999

Barley BLZ2, a seed-specific bZIP protein that interacts with BLZ1 in vivo and activates transcription from the GCN4-like motif of B-hordein promoters in barley endosperm.

A barley endosperm cDNA, encoding a DNA-binding protein of the bZIP class of transcription factors, BLZ2, has been characterized. The Blz2 mRNA expression is restricted to the endosperm, where it precedes that of the hordein genes. BLZ2, expressed in bacteria, binds specifically to the GCN4-like motif (GLM; 5'-GTGAGTCAT-3') in a 43-base pair oligonucleotide derived from the promoter region of a Hor-2 gene (B1-hordein). This oligonucleotide also includes the prolamin box (PB; 5'-TGTAAAG-3'). Binding by BLZ2 is prevented when the GLM is mutated to 5'-GTGctTCtc-3' but not when mutations affect the PB. The BLZ2 protein is a potent transcriptional activator in a yeast two-hybrid system where it dimerizes with BLZ1, a barley bZIP protein encoded by the ubiquitously expressed Blz1 gene. Transient expression experiments in co-bombarded developing barley endosperms demonstrate that BLZ2 transactivates transcription from the GLM of the Hor-2 gene promoter and that this activation is also partially dependent on the presence of an intact PB. A drastic decrease in GUS activity is observed in co-bombarded barley endosperms when using as effectors equimolar mixtures of Blz2 and Blz1 in antisense constructs. These results strongly implicate the endosperm-specific BLZ2 protein from barley, either as a homodimer or as a heterodimer with BLZ1, as an important transcriptional activator of seed storage protein genes containing the GLM in their promoters.

Amino Acid Sequence↗

PubMed2003

Supplements of transgenic malt or grain containing (1,3-1,4)-beta-glucanase increase the nutritive value of barley-based broiler diets to that of maize.

1. A diet with addition to normal barley of malt from transgenic barley expressing a protein engineered, thermotolerant Bacillus (1,3-1,4)-beta-glucanase during germination has previously been demonstrated to provide a broiler chicken weight gain comparable to maize diets. It also reduced dramatically the number of birds with adhering sticky droppings, but did not entirely eliminate sticky droppings. One of the objectives of the broiler chicken trials reported here was to determine if higher concentrations of transgenic malt could alleviate the sticky droppings. 2. Another aim was to investigate the feasibility of using mature transgenic grain containing the thermotolerant (1,3-1,4)-beta-glucanase as feed addition and to compare diets containing transgenic grain to a diet with the recommended amount of a commercial beta-glucanase-based product. 3. Inclusion of 75 or 151 g/kg transgenic malt containing 4.7 or 98 mg/kg thermotolerant (1,3-1,4)-beta-glucanase with 545 or 469 g/kg non-transgenic barley instead of maize yielded a weight gain in Cornish Cross broiler chickens indistinguishable from presently used maize diets. The gene encoding the enzyme is expressed in the aleurone with a barley alpha-amylase gene promoter and the enzyme is synthesised with a signal peptide for secretion into the endosperm of the malting grain. 4. Equal weight gain was achieved, when the feed included 39 g/kg transgenic barley grain [containing 66 mg/kg thermotolerant (1,3-1,4)-beta-glucanase] and 581 g/kg non-transgenic barley instead of maize. In this case, the gene encoding the enzyme has been expressed with the D-hordein gene (Hor3-1) promoter during grain maturation. The enzyme is synthesised as a precursor with a signal peptide for transport through the endoplasmic reticulum and targeted into the storage vacuoles. Deposition of the enzyme in the prolamin storage protein bodies of the endosperm protects it from degradation during the programmed cell death of the endosperm in the final stages of grain maturation and provides extraordinary heat stability. The large amount of highly active (1,3-1,4)-beta-glucanase in the mature grain allowed the reduction of the transgenic grain ingredient to 0.2 g/kg diet, thus making the ingredient comparable to that of the trace minerals added to standard diets. 5. A direct comparison using transgenic grain supplement at the level of 1 g/kg of feed with the standard recommended addition of the commercial enzyme preparation Avizyme 1100 at 1 g/kg yielded equal weight gain, feed consumption and feed efficiency in birds fed a barley-based diet. 6. The production of sticky droppings characteristic of broilers fed on barley diets was avoided with all 9 experimental diets and reduced to the level observed with a standard maize diet by supplementation with transgenic barley. 7. The excellent growth and normal survival of the 400 broilers tested on barley diets supplemented with transgenic grain or malt showed the grain and malt not to be toxic. 8. The barley feed with added transgenic grain or malt containing thermotolerant (1,3-1,4)-beta-glucanase provides an environmentally friendly alternative to enzyme additives, as it uses photosynthetic energy for production of the enzyme in the grain and thus avoids use of non-renewable energy for fermentation. The deposition of the enzyme in the protein bodies of the grain in the field makes coating procedures for stabilisation of enzyme activity superfluous. 9. Barley feed with the small amount of transgenic grain as additive to normal barley provides an alternative for broiler feed in areas where grain maize cannot be grown for climatic reasons or because of unsuitable soil and thus has to be imported.

Animal Feed↗

PubMed1993

Diagnosis and treatment of celiac sprue.

Celiac sprue, also termed celiac disease or gluten-sensitive enteropathy, is a chronic disease in which malabsorption of nutrients is caused by a characteristic, but nonspecific, lesion of the small-intestinal mucosa. The lesion is produced, through unclear mechanisms, by protein constituents of some cereal grains. Exclusion of wheat gluten and rye, barley, and oat prolamins from the diet results in a prompt improvement in absorption, along with reversion, toward normal, of the associated small-intestinal lesion. The spectrum of manifestations of celiac sprue is remarkably broad, but the severity of disease generally correlates with the length of small intestine that is damaged. When most or all of the small-intestinal mucosa is involved, symptoms are severe and malabsorption is generalized. In such patients, a diagnosis of celiac sprue is usually considered. When, on the other hand, the mucosal lesion is limited to the duodenum and proximal jejunum, overt gastrointestinal symptoms and steatorrhea may be absent. In those patients, clinical manifestations, if present at all, may reflect malabsorption of only one or two substances, notably iron and folate, that normally are absorbed somewhat selectively by the proximal intestine. Arriving at the correct diagnosis in such cases may be quite challenging.

Adult↗

PubMed1967

Studies of the activity of diphtheria toxin. I. Poliovirus replication in intoxicated HeLa cells.

It has been demonstrated that a saturating dose of diphtheria toxin produced a 90% inhibition of polio-virus replication in HeLa cells. This inhibition was reflected in infectious viral RNA synthesis and in mature virus production. Toxin had no direct effect on virus particles or I-RNA, and poliovirus adsorption and eclipse appeared to be carried out normally in intoxicated cells. When toxin was given at various time intervals after infection, the amount of inhibition depended on the time of toxin addition. Toxin given before or immediately after infection gave maximum inhibition, while toxin given several hours after infection had little effect. The data suggest that toxin inhibits viral replication through its effect on protein synthesis. It is likely that a critical step in the viral replication cycle, the production of poliovirus-induced RNA polymerase, is inhibited, and possibly the synthesis of capsid protein. Ammonium salts and the aliphatic amines, glycamine and prolamine, prevented the inhibition of viral replication by toxin. The kinetics of the protective action of ammonium chloride and diphtheria antitoxin are remarkably similar.

Diphtheria Toxin↗

PubMed2001

Genomewide linkage analysis of celiac disease in Finnish families.

Celiac disease (CD), or gluten-sensitive enteropathy, is a common multifactorial disorder resulting from intolerance to cereal prolamins. The only established genetic susceptibility factor is HLA-DQ, which appears to explain only part of the overall genetic risk. We performed a genomewide scan of CD in 60 Finnish families. In addition to strong evidence for linkage to the HLA region at 6p21.3 (Z(max)>5), suggestive evidence for linkage was found for six other chromosomal regions--1p36, 4p15, 5q31, 7q21, 9p21-23, and 16q12. We further analyzed the three most convincing regions--4p15, 5q31, and 7q21--by evaluation of dense marker arrays across each region and by analysis of an additional 38 families. Although multipoint analysis with dense markers provided supportive evidence (multipoint LOD scores 3.25 at 4p15, 1.49 at 5q31, and 1.04 at 7q21) for the initial findings, the additional 38 families did not strengthen evidence for linkage. The role that HLA-DQ plays was studied in more detail by analysis of DQB1 alleles in all 98 families. All but one patient carried one or two HLA-DQ risk alleles, and 65% of HLA-DQ2 carriers were affected. Our study indicates that the HLA region harbors a predominant CD-susceptibility locus in these Finnish families.

Adult↗

PubMed2004

The accumulation of alpha-zein in transgenic tobacco endosperm is stabilized by co-expression of beta-zein.

The cysteine-poor alpha-zein is the major prolamin storage protein fraction in maize endosperm and is localized in the interior of protein bodies with delta-zein, whereas the hydrophobic cysteine-rich beta- and gamma-zein are found on the exterior of the PB. In transgenic tobacco endosperm expressing zein genes, alpha-zein was unstable unless co-expressed with gamma-zein. Here we showed that alpha-zein was also stabilized by beta-zein. Small accretions of alpha- and beta-zeins, similar in appearance to maize protein bodies, were localized to the endoplasmic reticulum within tobacco endosperm cells. The zein proteins were also localized to protein storage vacuoles in a more dispersed pattern, suggesting that they were transported there after they were post-translationally sequestered into the ER.

Endoplasmic Reticulum↗

PubMed2004

Asymmetric localization of seed storage protein RNAs to distinct subdomains of the endoplasmic reticulum in developing maize endosperm cells.

Plant storage proteins are synthesized and stored in different compartments of the plant endomembrane system. Developing maize seeds synthesize and accumulate prolamin (zein) and 11S globulin (legumin-1) type proteins, which are sequestered in the endoplasmic reticulum (ER) lumen and storage vacuoles, respectively. Immunofluorescence studies showed that the lumenal chaperone BiP was not randomly distributed within the ER in developing maize endosperm but concentrated within the zein-containing protein bodies. Analysis of the spatial distribution of RNAs in maize endosperm sections by in situ RT-PCR showed that, contrary to the conclusions made in an earlier study [Kim et al. (2002) Plant Cell 14: 655-672], the zein and legumin-1 RNAs are not symmetrically distributed on the ER but, instead, targeted to specific ER subdomains. RNAs coding for 22 kDa alpha-zein, 15 kDa beta-zein, 27 kDa gamma-zein and 10 kDa delta-zein were localized to ER-bounded zein protein bodies, whereas 51 kDa legumin-1 RNAs were distributed on adjacent cisternal ER proximal to the zein protein bodies. These results indicate that the maize storage protein RNAs are targeted to specific ER subdomains in developing maize endosperm and that RNA localization may be a prevalent mechanism to sort proteins within plant cells.

Endoplasmic Reticulum↗

PubMed2001

Assessment of gliadin in supposedly gluten-free foods prepared and purchased by celiac patients.

BACKGROUND: The present study was designed to evaluate the presence of gliadin in homemade foods prepared by patients with celiac disease and/or their relatives, as well as in processed products consumed by such patients in São Paulo, Brazil, by enzyme immunoassay (EIA) and Western blot (WB) analysis. METHODS: One hundred ninety samples were analyzed: 108 homemade foods prepared in homes of patients with celiac disease, 81 processed products, and 1 positive control of homemade food. All samples were analyzed by EIA based on monoclonal antibodies to heat stable omega-gliadins and related prolamins from wheat, rye, and barley. Samples were also analyzed using the WB technique. RESULTS: Only one (0.9%) of 108 homemade foods contained detectable amounts of gliadin, as determined by EIA. Twelve of 81 processed products contained gliadin by EIA, as follows: 5 of 61 without gluten listed in the ingredients, 2 of 11 malt extracts, 1 of 2 wheat starches, 1 of 2 types of beer, and all 3 positive control products. Gliadin content of these products was between 4 and 10 mg of gliadin/100 g of product, except for the wheat starch sample (28 mg of gliadin/100 g) and all 3 samples with gluten (>4000 mg of gliadin/100 g). The positive control of homemade food contained 152 mg of gliadin/100 g. One hundred three of 190 samples were analyzed by WB, and 21 of these were gliadin positive. A comparison of results obtained by EIA and WB showed no statistical differences between the methods. CONCLUSIONS: The greater part of the foods prepared in homes of patients with celiac disease and most processed products supposed to be gluten-free did not contain gliadin. Therefore, celiac patients adequately prepare gluten-free homemade food and have the expertise to purchase processed gluten-free food in São Paulo, Brazil.

Antibodies, Monoclonal↗

PubMed1982

Experience with 49 segmental pancreas transplants in 45 diabetic patients.

Forty-nine pancreas transplants were performed in 45 patients between July 23, 1978 and May 14, 1982, 18 from related donors. Currently (June 1982), 13 patients have functioning grafts and are insulin independent between 1 and 46 months after transplantation, 5 for more than 1 year. Nineteen patients lost graft function between 1 and 7 months. Sixteen grafts failed for technical reasons. Eight patients died between 1 and 21 months from infections or preexisting complications or for unknown reasons, three with functioning grafts. Actuarial 1-year graft survival is 24% and patient survival is 84%. A variety of techniques were used to handle exocrine secretions of 41 hemipancreas segmental grafts, 4 extended segmental grafts, and 4 whole pancreas grafts. Currently, 3 of 14 duct-open, 0 of 2 duct-ligated, 0 of 4 prolamine-injected, 6 of 19 silicone rubber-injected, and 4 of 10 jejunal anastomosed pancreatic grafts are functioning. Of 33 technically successful allografts, 5 in 12 conventionally immunosuppressed and 8 in 21 cyclosporin A (Cy A)-immunosuppressed recipients are functioning. Most technically successful grafts that failed were not biopsied or removed. In those that were biopsied, fibrosis was a dominant feature in all but one patient. In this patient endocrine and exocrine tissue was normal except for the absence of insulin-positive (beta) cells in the islets and an increase in glucagon-positive (alpha) cells, in contrast to the normal appearance of alpha and beta cells in islets at the time of the pancreas transplant. Currently, we perform pancreas transplants in diabetic patients who have previously received kidney transplants and therefore already require immunosuppression. For nonuremic patients, we perform pancreas transplant only if it is judged that their complications of diabetes exceed, or predictably will exceed, the potential side effects of chronic immunosuppression.

Adult↗

PubMed2005

Development of a general procedure for complete extraction of gliadins for heat processed and unheated foods.

OBJECTIVES: In the past, one of the major problems in gluten analysis has been the unavailability of an efficient, universal, extraction procedure of gliadins - the alcohol-soluble proteins of gluten - from both heat processed and unprocessed products. This study was designed to develop a universal, extraction procedure capable of extracting the totality of gliadins from both unprocessed and heat processed foods for coeliac patients. METHODS: A simple quantitative extraction solution containing 250 mM 2-mercaptoethanol and 2 M guanidine hydrochloride ('cocktail'), was developed to extract gliadins from heated foods. RESULTS: The diluted reducing and disaggregating agents reaching the micro plate at low concentration do not affect the ELISA system based on the R5 monoclonal antibody. The recovery of gliadins extracted by the cocktail from spiked samples was nearly complete, with an average mean value of 95.5%, which is clearly superior to 44.4% obtained with conventional 60% aqueous ethanol. The cocktail always yielded either slightly similar or higher values than 60% aqueous ethanol depending on the type of foods: 1.1-fold in unheated foods, 1.4-fold in wheat starches and 3.0-fold in heated foods. False positives or negatives were never observed using the cocktail solution. CONCLUSION: We present a general complete gliadin extraction procedure based on reducing and disaggregating agents for both heated and unheated foods as a crucial tool for gliadin analysis. The new extraction solution is used for corresponding proteins from rye (secalins) and barley (hordeins). The cocktail was employed as the extraction method in the international ring trial evaluation of sandwich R5-ELISA as proposed by the Codex Alimentarius and organized by the Working Group on Prolamin Analysis and Toxicity.

Blotting, Western↗