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At least 19 recordsLinked to original sources

PubMed1996

Absence of cross-reactivity of IgE antibodies from subjects allergic to Hevea brasiliensis latex with a new source of natural rubber latex from guayule (Parthenium argentatum).

BACKGROUND: Natural rubber latex sensitization is caused by proteins from the latex of Hevea brasiliensis, the Brazilian rubber tree. Alternative non-cross-reactive latex rubber sources are needed for the manufacture of nonallergenic medical devices (e.g., catheters) that require elasticity, which is not currently provided by synthetic materials. METHODS: We have studied the ability of IgE antibodies from subjects allergic to Hevea latex and IgG antibodies from hyperimmunized mice to detect proteins derived from guayule (Parthenium argentatum), an alternative rubber source, using a direct binding and competitive inhibition RAST and Western blot analysis. RESULTS: IgE antibodies from 62 subjects allergic to Hevea latex (46 adults and 16 children with spina bifida) and from serum pools of adults allergic to Hevea latex (n = 183), pediatric patients (n = 101), and patients with spina bifida (n = 53), as well as IgG antibodies from hyperimmunized mice, were unable to detect any proteins in guayule by RAST or Western blot analysis. No competitive inhibition of IgE anti-Hevea binding to Hevea solid phase was detected by the preincubation of sera from subjects allergic to Hevea latex with soluble guayule latex before RAST analysis. CONCLUSIONS: These results demonstrate that proteins in guayule latex are not cross-reactive with Hevea latex allergens. Devices that require the elasticity provided by rubber may be manufactured with guayule latex as an alternative rubber source for patients with Hevea latex allergy.

Adult↗

PubMed2003

Molecular cloning, expression and characterization of cDNA encoding cis-prenyltransferases from Hevea brasiliensis. A key factor participating in natural rubber biosynthesis.

Natural rubber from Hevea brasiliensis is a high molecular mass polymer of isoprene units with cis-configuration. The enzyme responsible for the cis-1,4-polymerization of isoprene units has been idengified as a particle-bound rubber transferase, but no gene encoding this enzyme has been cloned from rubber-producing plants. By using sequence information from the conserved regions of cis-prenyl chain elongating enzymes that were cloned recently, we have isolated and characterized cDNAs from H. brasiliensis for a functional factor participating in natural rubber biosynthesis. Sequence analysis revealed that all of the five highly conserved regions among cis-prenyl chain elongating enzymes were found in the protein sequences of the Hevea cis-prenyltransferase. Northern blot analysis indicated that the transcript(s) of the Hevea cis-prenyltransferase were expressed predominantly in the latex as compared with other Hevea tissues examined. In vitro rubber transferase assays using the recombinant gene product overexpressed in Escherichia coli revealed that the enzyme catalyzed the formation of long chain polyprenyl products with approximate sizes of 2 x 103-1 x 104 Da. Moreover, in the presence of washed bottom fraction particles from latex, the rubber transferase activity producing rubber product of high molecular size was increased. These results suggest that the Hevea cis-prenyltransferase might require certain activation factors in the washed bottom fraction particles for the production of high molecular mass rubber.

Amino Acid Sequence↗

PubMed2006

Rubber Tree (Hevea brasiliensis Muell. Arg).

Rubber tree (Hevea brasiliensis Muell. Arg.) is an important industrial crop for natural rubber production. At present, more than 9.5 million hectares in about 40 countries are devoted to rubber tree cultivation with a production about 6.5 million tons of dry rubber each year. The world supply of natural rubber is barely keeping up with a global demand for 12 million tons of natural rubber in 2020. Tapping panel dryness (TPD) is a complex physiological syndrome widely found in rubber tree plantations, which causes severe yield and crop losses in natural rubber producing countries. Currently, there is no effective prevention or treatment for this serious malady. As it is a perennial tree crop, the integration of specific desired traits through conventional breeding is both time-consuming and labour-intensive. Genetic transformation with conventional breeding is certainly a more promising tool for incorporation of agronomically important genes that could improve existing Hevea genotype. This chapter provides an Agrobacterium-mediated transformation protocol for rubber tree using immature anther-derived calli as initial explants. We have applied this protocol to generate genetically engineered plants from a high yielding Indian clone RRII 105 of Hevea brasiliensis (Hb). Calli were co-cultured with Agrobacterium tumefaciens harboring a plasmid vector containing the Hb superoxide dismutase (SOD) gene and the reporter gene used was beta-glucuronidase (GUS) gene (uidA). The selectable marker gene used was neomycin phosphotransferase (nptII) and kanamycin was used as selection agent. We found that a suitable transformation protocol for Hevea consists of a 3-d co-cultivation with Agrobacterium in the presence of 20 mM acetosyringone, 15 mM betaine HCl, and 11.55 mM proline followed by selection on medium containing 300 mg/L kanamycin. Transformed calli surviving on medium containing 300 mg/L kanamycin showed a strong GUS-positive reaction. Upon subsequent subculture into fresh media, we obtained somatic embryogenesis and germinated plantlets, which were found to be GUS positive. The integration of uidA, nptII, and HbSOD transgenes into Hevea genome was confirmed by polymerase chain reaction (PCR) as well as Southern blot analysis.

Acetophenones↗

PubMed1991

Characterization of cDNA and genomic clones encoding 3-hydroxy-3-methylglutaryl-coenzyme A reductase from Hevea brasiliensis.

Hevea brasiliensis is the major producer of natural rubber which is cis-1,4-polyisoprene. The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) is involved in the biosynthesis of rubber and other plant products. We have used a hamster HMGR cDNA clone as a heterologous hybridization probe to isolate and characterize cDNA and genomic clones of HMGR from H. brasiliensis. Sequence analysis revealed that these clones fall into two different classes, HMGR1 and HMGR2. Comparison of the two classes shows 86% nucleotide sequence homology and 95% amino acid homology. The carboxy-termini of Hevea HMGRs are highly homologous to those of hamster, yeast and Arabidopsis HMGR. The amino-terminus of Hevea HMGR contains two potential membrane-spanning domains as in Arabidopsis HMGR while seven such domains are found in the HMGRs of other organisms. The apparent molecular mass of Hevea HMGR was estimated in western blot analysis to be 59 kDa. Northern blot analysis indicated that the HMGR1 transcript of 2.4 kb is more highly-expressed in laticifer than in leaf. Genomic Southern analysis using 3'-end cDNA probes indicates the presence of at least two HMGR genes in Hevea.

Amino Acid Sequence↗

PubMed1995

beta-1,3-Glucanase is highly-expressed in laticifers of Hevea brasiliensis.

Clones encoding beta-1,3-glucanase have been isolated from a Hevea cDNA library prepared from the latex of Hevea brasiliensis using a probe Nicotiana plumbaginifolia cDNA encoding beta-1,3-glucanase, gnl. Nucleotide sequence analysis showed that a 1.2 kb Hevea cDNA encoding a basic beta-1,3-glucanase showed 68% nucleotide homology to gnl cDNA. Northern blot analysis using the Hevea cDNA as probe detected a mRNA of 1.3 kb which was expressed at higher levels in latex than in leaf. In situ hybridization analysis using petiole sections from Hevea localized the beta-1,3-glucanase mRNA to the laticifer cells. Genomic Southern analysis suggested the presence of a low-copy gene family encoding beta-1,3-glucanases in H. brasiliensis.

Amino Acid Sequence↗

PubMed2002

Cloning and molecular characterization of the Hevea brasiliensis allergen Hev b 11, a class I chitinase.

BACKGROUND: In the last 10 years type-I allergy against proteins from Hevea brasiliensis latex has become an acknowledged medical issue. Fruit-allergic patients represent one risk group for developing latex allergy. Class I chitinases have been identified from chestnut, avocado and banana as relevant allergens. The chitin binding (hevein) domain from these class I chitinases has been postulated to bear the important IgE binding epitopes. OBJECTIVE: To clone the cDNA of an allergenic latex class I chitinase, to express the recombinant protein and to determine its IgE cross-reactivity with hevein (Hev b 6.02). METHODS: A full-length cDNA coding for a class I chitinase has been isolated from Hevea latex RNA by reverse transcription followed by PCR. The chitinase encoding sequence has been subcloned into the pMAL expression vector and expressed in E. coli as a fusion protein to maltose binding protein. The highly enriched recombinant protein fraction has been tested for its IgE binding capacity in immunoblots and ELISA. Furthermore, the pathogenesis-related function of the recombinant protein was tested in a fungal growth inhibition assay. RESULTS: The Hevea brasiliensis latex chitinase, designated Hev b 11, displays 70% identity to the endochitinase from avocado and its hevein-domain 58% to hevein (Hev b 6.02). The recombinant Hev b 11-maltose binding protein is recognized by latex- and fruit-allergic patients with IgE binding in both, ELISA and immunoblots. Pre-incubation of sera with rHev b 11-maltose binding protein showed an overall 16% inhibition of subsequent binding to rHev b 6.02-maltose binding protein on solid phase. The growth of F. oxysporum was inhibited in a dose dependent manner by addition of rHev b 11-maltose binding protein to the culture. CONCLUSIONS: Hev b 11, a class I chitinase, is another allergen from Hevea latex with a chitin binding domain and displays a different IgE binding capacity compared with hevein.

ATP-Binding Cassette Transporters↗

PubMed1976

Metabolism of ethephon (2-chloroethylphosphonic acid) and related compounds in Hevea brasiliensis.

Ethephon (I) is used commercially to prolong the flow of latex from the rubber tree after tapping (Yield stimulation). The compound is applied to the bark in the region of the tapping cut and the effect on latex flow is due to the ethylene released by chemical decomposition, since gaseous ethylene itself is also a very effective stimulant. When 14C-I is applied to the bark of a young Hevea seedling, it is absorbed into the plant by processes which appear to be largely non-metabolic. Ethylene formation commences immediately at the site of application, and the gas is quickly translocated throughout the plant. Translocation of I to all parts of the plant also occurs and the accumulation of 14C in the bark above the zone of application is greater than that below. Chromatographic analysis has shown that compounds other than I remain in the plant tissue. Experiments using 14C-I have shown that detached leaves are able to convert a considerable proportion of the compound to at least twelve non-volatile acid products. One of these is a conjugate of I with an unidentified material. A major component of the products is 2-hydroxyethylphosphonic acid (II), which is itself converted to a number of compounds in leaves. The application of I to bark from mature Hevea, results in the formation of a single substance which is also a conjugate of I. Neither I nor II is effective in inducing the formation of ethylene from endogenous precursors in vegetative Hevea tissue. Ethylene is poorly metabolized by Hevea leaves and the evidence available indicates that it is unlikely that any of the compounds produced from I are metabolites of ethylene.

Autoradiography↗

PubMed2000

Hev b 9, an enolase and a new cross-reactive allergen from hevea latex and molds. Purification, characterization, cloning and expression.

Natural rubber latex allergy is an IgE-mediated disease that is caused by proteins that elute from commercial latex products. A complementary DNA (cDNA) coding for Hev b 9, an enolase (2-phospho-D-glycerate hydrolyase) and allergen from latex of the rubber tree Hevea brasiliensis, was amplified by PCR. The PCR primers were designed according to conserved regions of enolases from plants. The obtained cDNA amplification product consisted of 1651 bp and encoded a protein of 445 amino-acid residues with a calculated molecular mass of 47.6 kDa. Sequence comparisons revealed high similarities of the Hevea latex enolase to mold enolases that have been identified as important allergens. In addition, the crucial amino-acid residues that participate in the formation of the catalytic site and the Mg2+ binding site of enolases were also conserved. Hevea latex enolase was produced as a recombinant protein in Escherichia coli with an N-terminal hexahistidyl tag, and purified by affinity chromatography. The yield amounted to 110 mg of purified Hev b 9 per litre of bacterial culture. The recombinant allergen bound IgE from latex, as well as mold-allergic patients, in immunoblot and ELISA experiments. The natural enolase was isolated from Hevea latex by (NH4)2SO4 precipitation and ion exchange chromatography. The natural and the recombinant (r)Hev b 9 showed equivalent enzymatic activity. Patients' IgE-antibodies preincubated with rHev b 9 lost their ability to bind to natural (n) Hev b 9, indicating the identity of the B-cell epitopes on both molecules. Cross-reactivity with two enolases from Cladosporium herbarum and Alternaria alternata was determined by inhibition of IgE-binding to these enolases by rHev b 9. Therefore, enolases may represent another class of highly conserved enzymes with allergenic potentials.

Adult↗

PubMed1995

The tonoplast-associated citrate binding protein (CBP) of Hevea brasiliensis. Photoaffinity labeling, purification, and cloning of the corresponding gene.

A detailed comparison of citrate uptake into the vacuole-like lutoids of rubber tree (Hevea brasiliensis Muell. Arg.) and of malate and citrate transport into barley (Hordeum vulgare L.) vacuoles revealed very similar transport specificities. In order to identify proteins mediating the transport, two photoreactive analogues (N'-(2-hydroxy-5-azido)-diazo-N-3,5-benzenedicarboxylic acid and 5-azidoisophthalic acid) of malate/citrate were synthesized and found to efficiently inhibit citrate uptake into barley vacuoles (Ki = 18 microM) and Hevea lutoid vesicles (Ki = 27 microM). In vacuoles from both plant species, these photoaffinity probes specifically labeled a single protein with a molecular mass of 23.6 kDa. This citrate binding protein (CBP) was purified to homogeneity from Hevea lutoids, and amino acid sequences were determined for NH2-terminal and tryptic peptides. Using degenerate oligonucleotides of the NH2-terminal sequence, a cDNA coding for the CBP protein of Hevea was isolated. The cDNA codes for a precursor protein of 238 amino acids, containing an NH2-terminal 31-amino acid signal sequence for endoplasmic reticulum targeting, a prerequisite for vacuolar localization. The mature CBP does not show significant sequence similarities to any known primary protein structure and thus represents a member of a novel class of proteins.

Affinity Labels↗

PubMed1996

Identification, cloning, and sequence of a major allergen (Hev b 5) from natural rubber latex (Hevea brasiliensis).

Proteins in commercial latex products, derived from the rubber tree Hevea brasiliensis, cause anaphylaxis in susceptible individuals, especially health care workers and children with spina bifida. To identify latex allergens, we utilized IgE from the serum of a latex-allergic health care worker to screen a cDNA library from Hevea latex. The identified cDNA clone, cDNA Hev b 5, encodes an open reading frame of 163 peptide residues. Hybridization analysis of cDNA Hev b 5 with RNA extracted from Hevea tissue indicates that the full-length transcript is about 1000 bases. The nucleotide and deduced protein sequences have significant homology to sequences from kiwi and potato, which are known to cause allergic reactions in some latex-allergic patients. Fifty-six percent of spina bifida patients and 92% of health care workers with latex allergy have IgE specific to the protein encoded by cDNA Hev b 5. A monoclonal antibody raised from a mouse immunized with Hev b 5 binds to a protein in Hevea latex with an Mr identical to that of the expressed and cleaved recombinant protein. Taken together, these results establish that the antigen Hev b 5 contains a major epitope for IgE-mediated reactions to H. brasiliensis latex products.

Adult↗

PubMed1983

Sensitivity of tonoplast-bound adenosine-triphosphatase from hevea to inhibitors.

The tonoplast-bound H(+)-translocating ATPase from Hevea latex was found to be insensitive to vanadate, diethylstilbestrol, and octylguanidine, which are specific inhibitors of the plasma membrane ATPase. The inhibitors of the mitochondrial ATPase, oligomycin and azide, and also rotenone and antimycin A, were all without effect. In contrast, trimethyltin chloride strongly inhibited the activity of Hevea tonoplast ATPase.Among the different carbodiimides tested, which strongly inhibit the Hevea tonoplast ATPase, N,N'-dicyclohexylcarbodiimide was the most inhibitory. N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline was also an efficient inhibitor.This unique inhibitor sensitivity of the Hevea tonoplast H(+)-translocating ATPase suggests that this enzyme differs in its mode of operation from all other known H(+)-translocating ATPases.

Journal Article↗

PubMed1996

[Geotropic reaction of different types of roots in Hevea brasiliensis].

To describe the different types of geotropic reactions of hevea (Hevea brasiliensis), young seedlings were cultivated in root observation boxes and submitted to a double gravistimulation (90 degrees rotation of the minirhizotrons in the vertical plane). It was demonstrated that the taproot is a strongly orthogeotropic organ since it resumed rapidly its prestimulation vertical position. Morphological and morphogenetic modifications were associated with the geotropic response: reduced speed of growth coupled with a reduction of the apical diameter as well as an alteration of ramification density in the curving zone and the following one. Early secondary roots showed a somewhat reduced orthogeotropism that was weaker as the growth direction before gravistimulation was more distant from the vertical. Secondary roots of the acropetal sequence were semiplagiotropic, that is only those roots oriented upward after the gravistimulation resumed, more or less, the original direction. Tertiary roots didn't respond to the gravistimulation and therefore were ageotropic. Complementary observations conducted in large laboratory rhizotrons showed that late forming secondary roots were plagiotropic in their younger stages, thereafter loosing most of their sensitivity to gravity. Quaternary roots were ageotropic. On the basis of these data, a geotropic gradient was defined within the hevea root system, where the strongly responding taproot and late secondary roots are opposed to the weakly or nonresponding tertiary and quaternary roots. Functional significations of the differential geotropic reactions in different hevea root types are discussed.

Gravitation↗

PubMed1995

Cross-reactivity of alternate plant sources of latex in subjects with systemic IgE-mediated sensitivity to Hevea brasiliensis latex.

BACKGROUND: Previous studies have suggested that there is cross-reactivity in subjects sensitive to natural rubber proteins with other plant proteins such as banana, chestnut, and avocado. There are numerous other plants known to produce rubber including Parthenium argentatum and Ficus elastica. It is not known whether patients with IgE-mediated systemic reactions caused by the common source of natural rubber Hevea brasiliensis are also sensitive to the rubber-containing material from these other plant sources of latex. It is also not certain how much the allergenicity of latex made from Hevea brasiliensis can be reduced by extracting proteins from the sap since some proteins are tightly associated with the cis-1,4-polyisoprene. OBJECTIVE: In this study we investigated whether there would be cross-reactivity to other natural sources of latex in these patients. METHODS: Seven patients with histories of systemic type I hypersensitivity to latex products had strongly positive skin tests to Hevea brasiliensis latex from two different sources. These subjects were tested by the prick method for sensitivity to three other natural sources of latex. These included latex-containing material from Parthenium-argentatum and Ficus elastica as well as washed and centrifuged rubber particles from Hevea brasiliensis sap. RESULTS: All subjects had negative skin tests to all dilutions of the rubber samples from these other natural sources of latex. CONCLUSION: These results suggest several potential sources of natural hypoallergenic latex that might be tolerated by latex-sensitive individuals.

Adult↗

PubMed2001

Cross-Reactivity studies of gutta-percha, gutta-balata, and natural rubber latex (Hevea brasiliensis).

Gutta-percha and gutta-balata are derived from the Paliquium gutta and Mimusops globsa trees, respectively, that are in the same botanical family as the rubber tree Hevea brasiliensis. For this reason the potential for immunological cross-reactivity between the gutta-percha and gutta-balata used in endodontics and natural rubber latex (NRL) has been the subject of some controversy, because these products may be used in latex-allergic individuals. The objective of this study was to investigate the potential cross-reactivity between gutta-percha, gutta-balata, and NRL. Physiological extracts of seven commercially available gutta-percha products, raw gutta-percha, raw gutta-balata, and synthetic transpolyisoprene were each analyzed for cross-reactivity with NRL in a competitive radioallergosorbent test inhibition assay. No detectable cross-reactivity was observed with any of the raw or clinically used gutta-percha products. In contrast the raw gutta-balata released proteins that were cross-reactive with Hevea latex. We conclude that the absence of gutta-percha proteins that can react with Hevea latex-specific IgE antibody supports the minimal potential for commercially available gutta-percha to induce allergic symptoms in individuals sensitized to NRL. Because gutta-balata is sometimes added to commercial gutta-percha products caution should be exercised if products containing gutta-balata are used in endodontic care of latex-allergic individuals.

Adult↗

PubMedDate not supplied

[Diversity and seasonal occurrence of mites (Acari) in a rubber tree crop (Hevea brasiliensis, Muell. Arg.) in northwestern São Paulo, Brazil].

Brazilian southeastern region has soil and climate conditions suitable for the growing of rubber trees, and most part of national yield arises from São Paulo State. The aims proposed for this work were to determine the diversity, the richness and the seasonal occurrence of mites found in a rubber tree crop in a triennial survey with monthly samplings, as well as to estimate the populational density of the major phytophagous species. This study found 74,407 mites from 26 species belonging to 10 families. The phytophagous and predators represented 95.4% and 3.9% of the total abundance, respectively. Twelve species were rare, six accessories and eight constant. The families Phytoseiidae and Tydeidae had the greatest richness (five and four species, respectively). The most numerous species was Calacarus heveae Feres (50,573), with great abundance at the end of rainy season until the beginning of dry season. Among predators, the most abundant were Zetzellia quasagistemas Hernandes & Feres (1,345), Pronematus sp. (455), Zetzellia agistzellia Hernandes & Feres (409) and Euseius citrifolius Denmark & Muma (243). C. heveae had greatest densities on March and April 2003, and Lorryia formosa Cooreman and Tenuipalpus heveae Baker on March and May 2001, respectively. Many stigmaeids were observed in association with colonies of L. formosa preying their eggs and immatures.

Animals↗

PubMed1995

Characterisation of HEVER, a novel stress-induced gene from Hevea brasiliensis.

A novel stress-induced gene, HEVER (Hevea ethylene-responsive) from the rubber tree, Hevea brasiliensis, has been isolated and characterised. HEVER is encoded by a multigene family. The HEVER transcript is expressed at basal levels in Hevea tissues and is developmentally regulated. In addition, the HEVER transcript and protein are induced by stress treatment with salicylic acid and ethephon. Sequence analysis shows that HEVER encodes a 33 kDa protein that has significant homology to the hypothetical protein SLEXORFA-1 from the plant, Stellaria longipes, and two bacterial proteins, BAC180K-75 from Bacillus subtilis and MVRNO3-1 from Methanococcus vannielii.

Amino Acid Sequence↗

PubMed1993

Molecular cloning, characterization and expression of Mn-superoxide dismutase from the rubber tree (Hevea brasiliensis).

A genomic clone encoding manganese-containing superoxide dismutase (SOD; EC 1.15.1.1) was isolated from a Hevea brasiliensis genomic library made in lambda phage EMBL3 by using a heterologous cDNA probe of MnSOD from Nicotiana plumbaginifolia. The nucleotide sequence of 4968 bp from the genomic clone was determined. Based on the putative translation initiation codon and stop codon, PCR primers were designed and utilized for cloning the full-length cDNA from total mRNA. Of the two distinct cDNAs of MnSOD isolated, MnSOD-A has a perfect match with exons of the nuclear gene, while MnSOD-B has a 90.2% homology and is 6 nucleotides longer than MnSOD-A in the putative transit peptide region. The nuclear gene comprises 6 exons and 5 introns, giving a total length of 3211 bp. The sequences of 1400 bp upstream of the initiation codon and 320 bp downstream of the stop codon were also determined. Southern analysis of genomic DNA from Hevea probed with a genomic fragment indicated there are at least two genes of MnSOD in Hevea. Northern blot analysis showed that MnSOD transcripts were present in all tissues examined (leaf, petiole, root, latex, callus) with young leaves showing the highest levels in intact plants. The transcript level in embryogenic callus was nearly 50-fold higher than in mature leaves. In addition, transcripts of MnSOD could be induced 3- to 5-fold in response to sucrose, ethephon and Murashige-Skoog salts.

Amino Acid Sequence↗

PubMed1987

Hevea Linamarase-A Nonspecific beta-Glycosidase.

In the leaf tissue of the cyanogenic plant Hevea brasiliensis, which contains large amounts of linamarin, there is no specific linamarase. In Hevea leaves only one beta-glucosidase is detectable. It is responsible for the cleavage of all beta-glucosides and beta-galactosides occurring in Hevea leaf tissue, including the cyanogenic glucoside linamarin. Therefore, the enzyme is referred to as a beta-glycosidase instead of the term beta-glucosidase. This beta-glycosidase has a broad substrate spectrum and occurs in multiple forms. These homo-oligomeric forms are interconvertible by dissociation-association processes. The monomer is a single protein of 64 kilodaltons.

Journal Article↗