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PubMed2001

Rye gamma-70 and gamma-35 secalins and barley gamma-3 hordein cross-react with omega-5 gliadin, a major allergen in wheat-dependent, exercise-induced anaphylaxis.

Patients with wheat-dependent, exercise-induced anaphylaxis experience severe allergic reactions when exercising after ingestion of wheat. The major wheat allergen associated with these reactions is a omega-5 gliadin, and patients following a gluten-free diet have remained free of symptoms. The aim of this study was to examine whether allergens cross-reacting with wheat omega-5 gliadin are present in rye, barley and oats. Sera from 23 adult patients with wheat-dependent, exercise-induced anaphylaxis were examined. Cereal allergens cross-reacting with wheat omega-5 gliadin were identified by immunoblot inhibition. The cross-reactive allergens were purified by gel filtration and reversed-phase chromatography and submitted to amino acid sequencing. Cross-reactivity was further studied by IgE ELISA and ELISA inhibition, and in vivo reactivity by skin prick testing. In immunoblotting rabbit anti-omega-5 gliadin antibodies bound to 70 kDa and 32 kDa proteins in rye and a 34-kDa protein in barley, but not to proteins in oats. N-terminal sequencing identified these proteins as rye gamma-70 secalin, rye gamma- 35 secalin and barley gamma-3 hordein, correspondingly. In ELISA 21/23 (91%) patients with wheat-dependent, exercise-induced anaphylaxis showed IgE antibodies to purified gamma-70 secalin, 19/23 (83%) to gamma-35 secalin and 21/23 (91%) to gamma-3 hordein. In ELISA inhibition omega-5 gliadin inhibited over 90% of the IgE binding of pooled patient sera to solid-phase gamma-secalins and gamma-3 hordein. Skin prick testing gave positive reactions to gamma-70 secalin in 10/15 (67%) patients, to gamma-35 secalin in 3/15 (20%) patients and to gamma-3 hordein in 7/15 (47%) patients. The results of this study show that gamma-70 and gamma-35 secalins in rye and gamma-3 hordein in barley cross-react with omega-5 gliadin, a major allergen in wheat-dependent, exercise-induced anaphylaxis. These findings suggest that also rye and barley may elicit symptoms in patients with wheat-dependent, exercise-induced anaphylaxis.

Adolescent↗
PubMed2004

Comparison of wheat and rye flour skin prick test solutions for diagnosis of baker's asthma.

BACKGROUND: Skin prick tests (SPTs) play an important role in the diagnosis of baker's asthma and in the investigation of sensitization frequencies in field studies. It was the aim of our study to compare different SPT solutions for wheat and rye flour sensitization and to assess the validity of test results. METHODS: Skin prick tests with wheat and rye flour were performed in parallel with extracts from different companies and compared with the results of bronchial challenge tests with both flours (69 rye flour and 51 wheat flour challenge tests). Additionally, specific immunoglobulin E (sIgE) to wheat and rye flour were tested. SPT solutions were analysed for protein content and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). RESULTS: Skin prick test solutions for diagnosis of wheat and rye flour sensitization from three companies differed in protein concentrations and composition with the consequence of widely differing SPT results. Sensitivity of SPTs in comparison with allergen-specific bronchial challenge as a gold standard was between 40 and 67%, specificity was between 86 and 100%, the positive predictive value (PPV) ranged from 81 to 100% and the negative predictive value (NPV) from 44 to 70%. These numbers were only marginally affected by using a combination of challenge test result and sIgE value as a more specific gold standard. CONCLUSION: Improvement and standardization of SPT extracts for wheat and rye flour is highly recommended.

Adult↗
PubMed2003

Deoxynivalenol and other Fusarium toxins in wheat and rye flours on the Danish market.

Information on the contamination of Danish cereals and cereal products with Fusarium toxins is limited and the last survey is from 1984/1985. In the present study, the occurrence of deoxynivalenol (DON), nivalenol (NIV), HT-2 toxin, T-2 toxin and zearalenone (ZON) was investigated in flour of common wheat, durum wheat and rye. The samples were collected from 1998 to 2001 from both mills and the retail market in Denmark. A total of 190 flour samples were analysed for DON and NIV and about 60 samples for HT-2, T-2 toxin and ZON. DON was most frequently detected with an incidence rate of 78% over all samples for all years. The contamination level varied considerably from year to year, and for wheat and rye the highest incidence and DON concentrations were found in samples from the 1998 harvest. There were regular and heavy rainfalls in Denmark during the flowering period of the crops that year, and DON was found in all samples, with mean concentrations in wheat and rye flour of 191 microg kg(-1) (n=14) and 99 microg kg(-1) (n=16), respectively. Comparison of data from each harvest year showed higher contents of DON in samples of wheat (range 20-527 microg kg(-1)) than in rye (20-257 microg kg(-1)). Contents of NIV, HT-2 toxin and ZON in samples of wheat and rye were generally low, and even in positive samples the contents were close to the detection limit of the methods. The T-2 toxin was detected in only a few of the wheat samples and in low amounts. However, the toxin was found in about 50% of the rye samples collected during 1998-2000, with a mean content of 49 microg kg(-1) (n=25). Durum wheat flour showed the highest DON contamination level, and all samples (n=33) collected during 2000 and 2001 contained DON with means and medians above 1100 microg kg(-1). Over 70% of the samples contained more than 500 microg kg(-1) DON, and the highest observed concentration was 2591 microg kg(-1). The concentration of T-2 toxin in durum wheat flour was also high with five of the 10 analysed samples containing more than 100 g kg(-1).

Denmark↗
PubMed2003

High-fiber rye bread and insulin secretion and sensitivity in healthy postmenopausal women.

BACKGROUND: Fiber and whole-cereal intakes may protect against hyperinsulinemia and the risk of type 2 diabetes. OBJECTIVE: The aim was to study whether the long-term use of high-fiber rye bread and white-wheat bread modifies glucose and insulin metabolism in healthy postmenopausal women. DESIGN: The study was a randomized crossover trial consisting of 8-wk test and 8-wk washout periods. The subjects were 20 postmenopausal women [macro x +/- SD age: 59 +/- 6.0 y; body mass index (in kg/m(2)): 27.5 +/- 2.9; baseline fasting serum cholesterol: 6.5 +/- 0.8 mmol/L], of whom 3 had impaired glucose tolerance as determined by a 2-h oral-glucose-tolerance test. The test breads were high-fiber rye and white-wheat breads, planned to make up > or =20% of energy. Fasting blood samples were collected for the measurement of plasma glucose and insulin at the beginning and at the end of both bread periods. The frequently sampled intravenous-glucose-tolerance test was performed at the run-in and at the end of both bread periods. The acute insulin response, insulin sensitivity, and glucose effectiveness were calculated. RESULTS: The rye bread made up 23.4 +/- 4.3% and wheat bread 26.7 +/- 8.2% of total energy intake. Compared with that during the run-in period, the acute insulin response increased significantly more during the rye bread period (9.9 +/- 24.2%) than during the wheat bread period (2.8 +/- 36.3%; P = 0.047). Other measured variables did not change significantly during the study. CONCLUSIONS: Modification of carbohydrate intake by high-fiber rye bread did not alter insulin sensitivity in postmenopausal, hypercholesterolemic women. High-fiber rye bread appears to enhance insulin secretion, possibly indicating improvement of b cell function.

Area Under Curve↗
PubMed1999

Effects of soy or rye supplementation of high-fat diets on colon tumour development in azoxymethane-treated rats.

Evidence is accumulating that a diet high in plant-derived foods may be protective against cancer. One class of plant component under increasing investigation is the phytoestrogens of which there are two main groups: the isoflavones, found mainly in soy products, and the lignans, which are more ubiquitous and are found in fruit, vegetables and cereals with high levels being found in flaxseed. In this study, we have used carefully balanced high-fat (40% energy) diets: a control diet (containing low isoflavone soy protein as the sole protein source), a rye diet (the control diet supplemented with rye bran) and a soy diet (containing as protein source a high isoflavone soy protein). The effect of these diets on the development of colonic cancer was studied in F-344 rats treated with the carcinogen, azoxymethane (two doses of 15 mg/kg given 1 week apart). Colons from treated animals were examined for aberrant crypt foci (ACF) and tumours after 12 and 31 weeks. Results after 12 weeks showed no differences in the total number of ACF in the control, soy or rye bran groups. However, the soy group had increased numbers of small ACF (less than four crypts/focus) while the rye group had decreased numbers of large ACF (greater than six crypts/focus). Examination of colons after 31 weeks gave similar low numbers of ACF in each group with no differences in multiplicity. There were no differences in the number of tumours between the control (1.36 tumours/rat) and soy (1.38 tumours/rat) groups. However, there was a significant decrease in the number of tumours in the rye group (0.17 tumours/rat). These results suggest that soy isoflavones have no effect on the frequency of colonic tumours in this model while rye bran supplementation decreases the frequency of colon cancer. This effect is due not to a decrease in early lesions but in their progression to larger multi-crypt ACF. The study also supports the hypothesis that larger ACF are more predictive of subsequent tumorigenicity.

Animals↗
PubMed2000

Beef induces and rye bran prevents the formation of intestinal polyps in Apc(Min) mice: relation to beta-catenin and PKC isozymes.

Epidemiological studies suggest that high consumption of red meat and saturated fat and low consumption of fiber are associated with an increased risk of colon cancer. Therefore, we studied whether diets high in red meat or high in different grain fibers as well as inulin, polydisperse beta(2-->1) fructan, could affect the formation of intestinal polyps in Apc(Min) mice. Min mice were fed the following high-fat (40% of energy) diets for 5-6 weeks; a high-beef diet and a casein-based diet without added fiber or casein-based diet with 10% (w/w) oat, rye or wheat bran, or 2.5% (w/w) inulin. One group had a normal low-fat AIN93-G diet. The mice fed the rye-bran diet had the lowest number of polyps in the distal small intestine [15.4 +/- 8.7 (mean +/- SD)], and in the entire intestine (26.4 +/- 12.1). The rye-bran group differed significantly (P = 0. 001-0.004) from the beef group (36.6 +/- 9.4 and 52.8 +/- 13.2). In addition, the beef group differed significantly from the AIN93-G group (P = 0.009) and also from the wheat-bran group (21.0 +/- 6.1 and 35.0 +/- 8.2; P = 0.02) in the distal small intestine. The inulin group (32.9 +/- 14.3 and 49.3 +/- 16.3), on the other hand, was close to the beef group and it differed significantly from the rye-bran group in the distal small intestine. The number of animals bearing tumors in the colon + caecum was only 33% in the rye-bran group when compared with 89% in the beef and 100% in the inulin groups. The mice fed the rye-bran and beef diets had the lowest levels of cytosolic beta-catenin (0.60 +/- 0.42 and 0.67 +/- 0.26) and they differed significantly (P = 0.040 and 0.062) from the mice fed the oat-bran diet (1.46 +/- 0.43). No differences between groups in expression of protein kinase C (PKC) alpha, betaII, delta and zeta were found. The four PKC isozymes were positively correlated with cytosolic beta-catenin levels (r = 0.62-0.68; P < 0.0001).

Animals↗
PubMed1993

Freeze-Induced Membrane Ultrastructural Alterations in Rye (Secale cereale) Leaves.

Freezing injury in protoplasts isolated from leaves of nonaccli-mated rye (Secale cereale cv Puma) is associated with the formation of the inverted hexagonal (HII) phase. However, in protoplasts from cold-acclimated rye, injury is associated with the occurrence of localized deviations in the fracture plane, a lesion referred to as the "fracture-jump lesion." To establish that these ultrastructural consequences of freezing are not unique to protoplasts, we have examined the manifestations of freezing injury in leaves of non-acclimated and cold-acclimated rye by freeze-fracture electron microscopy. At -10[deg]C, injury in nonacclimated leaves was manifested by the appearance of aparticulate domains in the plasma membrane, aparticulate lamellae subtending the plasma membrane, and by the frequent occurrence of the HII phase. The HII phase was not observed in leaves of cold-acclimated rye frozen to -35[deg]C. Rather, injury was associated with the occurrence of the fracture-jump lesion between the plasma membrane and closely appressed cytoplasmic membranes. Studies of the time dependence of HII phase formation in nonacclimated leaves indicated that freeze-induced dehydration requires longer times in leaves than in isolated protoplasts. These results demonstrate that the freeze-induced formation of the HII phase in nonacclimated rye and the fracture-jump lesion in cold-acclimated rye are not unique to protoplasts but also occur in the leaves from which the protoplasts are isolated.

Journal Article↗
PubMed2006

Cold-active winter rye glucanases with ice-binding capacity.

Extracellular pathogenesis-related proteins, including glucanases, are expressed at cold temperatures in winter rye (Secale cereale) and display antifreeze activity. We have characterized recombinant cold-induced glucanases from winter rye to further examine their roles and contributions to cold tolerance. Both basic beta-1,3-glucanases and an acidic beta-1,3;1,4-glucanase were expressed in Escherichia coli, purified, and assayed for their hydrolytic and antifreeze activities in vitro. All were found to be cold active and to retain partial hydrolytic activity at subzero temperatures (e.g. 14%-35% at -4 degrees C). The two types of glucanases had antifreeze activity as measured by their ability to modify the growth of ice crystals. Structural models for the winter rye beta-1,3-glucanases were developed on which putative ice-binding surfaces (IBSs) were identified. Residues on the putative IBSs were charge conserved for each of the expressed glucanases, with the exception of one beta-1,3-glucanase recovered from nonacclimated winter rye in which a charged amino acid was present on the putative IBS. This protein also had a reduced antifreeze activity relative to the other expressed glucanases. These results support the hypothesis that winter rye glucanases have evolved to inhibit the formation of large, potentially fatal ice crystals, in addition to having enzymatic activity with a potential role in resisting infection by psychrophilic pathogens. Glucanases of winter rye provide an interesting example of protein evolution and adaptation aimed to combat cold and freezing conditions.

Amino Acid Sequence↗
PubMed1996

Immunolocalization of Antifreeze Proteins in Winter Rye Leaves, Crowns, and Roots by Tissue Printing.

During cold acclimation, antifreeze proteins (AFPs) that are similar to pathogenesis-related proteins accumulate in the apoplast of winter rye (Secale cereale L. cv Musketeer) leaves. AFPs have the ability to modify the growth of ice. To elucidate the role of AFPs in the freezing process, they were assayed and immunolocalized in winter rye leaves, crowns, and roots. Each of the total soluble protein extracts from cold-acclimated rye leaves, crowns, and roots exhibited antifreeze activity, whereas no antifreeze activity was observed in extracts from nonacclimated rye plants. Antibodies raised against three apoplastic rye AFPs, corresponding to a glucanase-like protein (GLP, 32 kD), a chitinase-like protein (CLP, 35 kD), and a thaumatin-like protein (TLP, 25 kD), were used in tissue printing to show that the AFPs are localized in the epidermis and in cells surrounding intercellular spaces in cold-acclimated plants. Although GLPs, CLPs, and TLPs were present in nonacclimated plants, they were found in different locations and did not exhibit antifreeze activity, which suggests that different isoforms of pathogenesis-related proteins are produced at low temperature. The location of rye AFPs may prevent secondary nucleation of cells by epiphytic ice or by ice propagating through the xylem. The distributions of pathogenesis-induced and cold-accumulated GLPs, CLPs, and TLPs are similar and may reflect the common pathways by which both pathogens and ice enter and propagate through plant tissues.

Journal Article↗
PubMed2000

Pattern of aluminum-induced secretion of organic acids differs between rye and wheat.

Al-Induced secretion of organic acids from the roots has been considered as a mechanism of Al tolerance, but the processes leading to the secretion of organic acids are still unknown. In this study, the secretion pattern and alteration in the metabolism of organic acids under Al stress were examined in rye (Secale cereale L. cv King) and wheat (Triticum aestivum L. cv Atlas 66). Al induced rapid secretion of malate in the wheat, but a lag (6 and 10 h for malic and citric acids, respectively) between the exposure to Al and the secretion of organic acids was observed in the rye. The activities of isocitrate dehydrogenase, phosphoenolpyruvate carboxylase, and malate dehydrogenase were not affected by Al in either plant. The activity of citrate synthase was increased by the exposure to Al in the rye, but not in the wheat. The secretion of malate was not suppressed at low temperature in the wheat, but that of citrate was stopped in the rye. The Al-induced secretion of citrate from roots of the rye was inhibited by the inhibitors of a citrate carrier, which transports citrate from the mitochondria to the cytoplasm. All of these results suggest that alteration in the metabolism of organic acids is involved in the Al-induced secretion of organic acids in rye, but only activation of an anion channel seems to be responsible for the rapid secretion of malate in the wheat.

Aluminum↗
PubMed2001

Ethylene induces antifreeze activity in winter rye leaves.

Antifreeze activity is induced by cold temperatures in winter rye (Secale cereale) leaves. The activity arises from six antifreeze proteins that accumulate in the apoplast of winter rye leaves during cold acclimation. The individual antifreeze proteins are similar to pathogenesis-related proteins, including glucanases, chitinases, and thaumatin-like proteins. The objective of this study was to study the regulation of antifreeze activity in response to ethylene and salicyclic acid, which are known regulators of pathogenesis-related proteins induced by pathogens. Nonacclimated plants treated with salicylic acid accumulated apoplastic proteins with no antifreeze activity. In contrast, when nonacclimated plants were exposed to ethylene, both antifreeze activity and the concentration of apoplastic protein increased in rye leaves. Immunoblotting revealed that six of the seven accumulated apoplastic proteins consisted of two glucanases, two chitinases, and two thaumatin-like proteins. The ethylene-releasing agent ethephon and the ethylene precursor 1-aminocyclopropane-1-carboxylate also induced high levels of antifreeze activity at 20 degrees C, and this effect could be blocked by the ethylene inhibitor AgNO(3). When intact rye plants were exposed to 5 degrees C, endogenous ethylene production and antifreeze activity were detected within 12 and 48 h of exposure to cold, respectively. Rye plants exposed to drought produced both ethylene and antifreeze activity within 24 h. We conclude that ethylene is involved in regulating antifreeze activity in winter rye in response to cold and drought.

Antifreeze Proteins↗
PubMed1973

Partial characterization of oat and rye phytochrome.

Purified oat and rye phytochrome were examined by analytical gel chromatography, polyacrylamide gel electrophoresis, N-terminal, and amino acid analysis. Purified oat phytochrome had a partition coefficient on Sephadex G-200 (sigma(200)) of 0.350 with an estimated molecular weight of 62,000; sodium dodecyl sulfate polyacrylamide electrophoresis gave an equivalent weight estimate. Purified rye phytochrome had a sigma(200) value of 0.085 with an estimated molecular weight of 375,000; sodium dodecyl sulfate electrophoresis gave a weight estimate of 120,000, indicating a multimer structure for the nondenatured protein. Comparative sodium dodecyl sulfate electrophoresis with purified phycocyanin and allophycocyanin gave a molecular weight estimate of 15,000 for allophycocyanin, and two constituent classes of subunits for phycocyanin with molecular weights of 17,000 and 15,000. Amino acid analysis of oat phytochrome confirmed a previous report; amino acid analysis of rye phytochrome differs markedly from a previous report. Oat phytochome has four detectable N-terminal residues (glutamic acid, serine, lysine, and leucine, or isoleucine); rye phytochrome has two detectable groups (aspartic and glutamic acids). Model experiments subjecting purified rye phytochrome to proteinolysis generate a product with the characteristic spectral and weight properties of oat phytochrome, as it has been described in the literature. It is concluded that the structural characteristics of purified rye phytochrome are likely those of the native protein.

Journal Article↗
PubMed2004

Phylogenetic relationships among genotypes of worldwide collection of spring and winter ryes (Secale cereale L.) determined by RAPD-PCR markers.

Genetic similarities among 20 spring and 22 winter accessions of agronomically different ryes from fourteen countries were estimated by employing random amplified polymorphic DNA (RAPD) techniques. Cluster analysis of genetic distance data showed that 42 genotypes were readily classifiable into two main groups: spring and winter groups. Within the spring group, cultivars fell into a North European and an American-Chinese group. Cultivars of winter rye fell into four groups: Northern European, Russian, American and Chinese lines. A UPGMA-dendrogram based on genetic distances of cultivars of rye within the winter and spring groups showed that the clusters corresponded well to their geographical locations. The results indicated that isolation has played an important role in the evolution of rye, and that temporal isolation has influenced the genetic diversity of rye more than geographical isolation. In this experiment, RAPD proved to be a rapid, reliable and practicable method of revealing polymorphisms in rye populations.

Ecosystem↗
PubMed1976

Colonization of rye green manure and peanut fruit debris by Aspergillus falvus and Aspergillus niger group in field soils.

Aspergillus flavus and Aspergillus niger group colonization of deep-plowed, decomposing rye green manure cover crops in peanut field soils was studied in four fields during 1972 and 1973; colonization of decomposing peanut fruits was studied in 1972 in two fields. A. flavus colonization of rye and peanut fruits was greater in soils of heavy texture, and an A. flavus population as high as 165 propagules per g of soil was observed in soil adjacent to rye, whereas A. flavus populations in soils not associated with rye were 18 propagules per g of soil or lower. Highest A. flavus populations in soil adjacent to decomposing peanut fruits were usually comparable to populations associated with rye. Little decomposing rye or peanut fruit colonization was generally observed by the A. flavus competitor, A. niger group. A. flavus may maintain or increase its inoculum potential by colonization of these and other moribund plant tissues.

Antibiosis↗
PubMed2006

Effects of phytoestrogen extracts isolated from rye, green and yellow pea seeds on hormone production and proliferation of trophoblast tumor cells Jeg3.

BACKGROUND: Phytoestrogens are a diverse group of non-steroidal plant compounds. Because they have chemical structures similar to estrogens they are able to bind on estrogen receptors in humans. OBJECTIVES: In this study, we tested the effects of crude phytoestrogen extracts from rye (Secale cereale), green pea (Pisum sativum) and yellow pea seeds (Pisum sativum cv.) on cell proliferation and the production of progesterone in trophoblast tumor cells of the cell line Jeg3. METHODS: Isoflavone extracts from green and yellow pea seeds and lignan extracts from rye seeds were obtained, using different extraction methods. Isolated extracts were incubated in different concentrations with trophoblast tumor cells. Untreated cells were used as controls. At designated times, aliquots were removed and tested for estradiol and progesterone production. In addition, we tested the effects of the phytoestrogen extracts on cell proliferation. RESULTS: Cell proliferation is significantly inhibited by potential phytoestrogens isolated from rye, green and yellow pea seeds in trophoblast tumor cells of the cell line Jeg3. We found a correlation between the effects of proliferation and production of estradiol in isoflavone extracts from green and yellow pea seeds in Jeg3 cells. In addition, higher concentrations of isoflavones isolated from green pea seeds and lignans from rye showed also a inhibition of progesterone production whereas higher concentrations of rye lignans elevated estradiol production in Jeg3 cells. CONCLUSION: A useful indicator test system for potential phytoestrogens could be established. Based on the obtained results it is proposed that green and yellow pea seeds contain measurable concentrations of isoflavones and rye seeds contain lignans which can be isolated and used for special human diet programs.

Cell Line, Tumor↗
PubMed1982

Antibody response profiles to components of rye grass pollen extract in various strains of mice.

Using a combination of immunoprecipitation and polyacrylamide gel electrophoresis techniques, patterns of antibody responses to a number of components in rye pollen extract have been studied in hyperimmune mouse sera. Common laboratory strains of mice were investigated, including AKR, C3H/He, SwR, Ist, Asn, Balb/c, C57BL10, DBA2 and BD1:F1 hybrids. All strains responded vigorously to the immunisation protocol used (rye pollen extract/alum followed by a booster dose in aqueous media) when tested with non-discriminating assay procedures such as haemagglutination or passive cutaneous anaphylaxis directed against the whole rye pollen extract. However, markedly variable antibody responses were observed between strains and between murine and human sera when considered in relation to individual rye extract components. Particularly noteworthy was the relatively poor response of all mice to the low molecular weight rye antigen component (11,000 daltons). This material was readily detected by human sera derived from pollenosis patients. Notable also was the fact that no single rye component was detected by all mice sera. These results illustrate the complex serological response induced by heterogeneous antigen mixtures, such as grass pollen extracts.

Animals↗
PubMed1984

Accessory cell response to rye grass pollen extract in mice, guinea pigs and man.

The ability of murine, guinea-pig and human accessory cells to function in antigen presentation has been assayed by a T-cell proliferative response to adherent cells pulsed with rye grass pollen extract. A population of phagocytic, esterase-positive, plastic-adherent splenocytes from non-immune Balb/c mice briefly incubated with solubilized rye antigen were capable of stimulating syngeneic T lymphocytes from immune mice in an antigen-specific manner. Accessory cell function was H-2 restricted and required Ia-positive cells. Treatment with a monoclonal anti-Ia antibody impaired proliferation, whereas the presence of polyclonal rabbit anti-rye antibody increased activity. Guinea-pig peritoneal and alveolar adherent cells pulsed with up to 1 mg/ml antigen increased the response of rye-immune lymph node T cells in vitro. Proliferation was dose-dependent, despite less than 0.1% of the available antigen being cell-associated, and could be inhibited by treating the accessory cells with trypsin, sodium iodoacetate and chloroquine. Adherent human peripheral blood cells treated with rye antigen supported the proliferation of non-adherent and nylon wool-enriched mononuclear cells obtained from both grass pollen-sensitive donors and from individuals lacking either detectable serum IgE antibody or a positive skin test to rye antigen.

Adult↗
PubMed1992

Different patterns of rDNA organization at interphase in nuclei of wheat and rye.

The physical location of the rDNA repeating units (25 S, 18 S and 5.8 S rRNA genes and the intergenic spacer sequences) was investigated in rye (Secale cereale L.) and wheat (Triticum aestivum L.) root tip meristematic cells by in situ hybridization using light and electron microscopy. The rDNA sequences are organized differently in the two related and intercrossable species. In rye (2n = 14, one pair of chromosomes with nucleolar organizing regions, NORs), two condensed blocks of rDNA-containing chromatin occurred in each interphase nucleus. The blocks were associated with the periphery of nucleoli and a single-labelled, decondensed rDNA fibre extended into the nucleolus from the block. We term this expression pattern terminal decondensation. In wheat (2n = 6x = 42, five pairs of chromosomes with NORs), inactive condensed labelled chromatin was found unassociated with nucleoli. Active NORs had some condensed rDNA associated with the nucleolar periphery, but, in contrast to rye, condensed rDNA was also found within the nucleolus. The condensed labelled rDNA in wheat nucleoli was visible as fluorescent foci in the light microscope and labelled condensed chromatin in the electron microscope. Its absence in rye shows that condensed rDNA need not be present in active plant nucleoli. Diffuse labelled sites of rDNA, likely to represent actively transcribed rDNA, were found in both rye and wheat. Active rDNA loci in wheat have many expressed segments separated by unexpressed, condensed, rDNA-fragmented decondensation-while each locus in rye has a single, unexpressed perinucleolar condensed block of rRNA genes. Thus the positions of actively transcribed genes within the tandem arrays of rDNA at each locus are fundamentally different in the two cereals. The NOR chromosome appeared to extend through the nucleolus, and active rDNA sequences did not loop out from chromatin into the nucleolus as is frequently described in nucleolar models.

Cell Nucleolus↗