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At least 19 recordsLinked to original sources
PubMed1985

Intracellular pH Regulation during NO(3) Assimilation in Shoot and Roots of Ricinus communis.

Ricinus communis L. was used to test the Dijkshoorn-Ben Zioni hypothesis that NO(3) (-) uptake by roots is regulated by NO(3) (-) assimilation in the shoot. The fate of the electronegative charge arising from total assimilated NO(3) (-) (and SO(4) (2-)) was followed in its distribution between organic anion accumulation and HCO(3) (-) excretion into the nutrient solution. In plants adequately supplied with NO(3) (-), HCO(3) (-) excretion accounted for about 47% of the anion charge, reflecting an excess nutrient anion over cation uptake. In vivo nitrate reductase assays revealed that the roots represented the site of about 44% of the total NO(3) (-) reduction in the plants. To trace vascular transport of ionic and nitrogenous constituents within the plant, the composition of both xylem and phloem saps was thoroughly investigated. Detailed dry tissue and sap analyses revealed that only between 19 and 24% of the HCO(3) (-) excretion could be accounted for from oxidative decarboxylation of shoot-borne organic anions produced in the NO(3) (-) reduction process. The results obtained in this investigation may be interpreted as providing direct evidence for a minor importance of phloem transport of cation-organate for the regulation of intracellular pH and electroneutrality, thus practically eliminating the necessity for the Dijkshoorn-Ben Zioni recycling process.

Journal Article↗
PubMed1988

Influence of Nitrate and Ammonium Nutrition on the Uptake, Assimilation, and Distribution of Nutrients in Ricinus communis.

Ricinus communis L. plants were grown in nutrient solutions in which N was supplied as NO(3) (-) or NH(4) (+), the solutions being maintained at pH 5.5. In NO(3) (-)-fed plants excess nutrient anion over cation uptake was equivalent to net OH(-) efflux, and the total charge from NO(3) (-) and SO(4) (2-) reduction equated to the sum of organic anion accumulation plus net OH(-) efflux. In NH(4) (+)-fed plants a large H(+) efflux was recorded in close agreement with excess cation over anion uptake. This H(+) efflux equated to the sum of net cation (NH(4) (+) minus SO(4) (2-)) assimilation plus organic anion accumulation. In vivo nitrate reductase assays revealed that the roots may have the capacity to reduce just under half of the total NO(3) (-) that is taken up and reduced in NO(3) (-)-fed plants. Organic anion concentration in these plants was much higher in the shoots than in the roots. In NH(4) (+)-fed plants absorbed NH(4) (+) was almost exclusively assimilated in the roots. These plants were considerably lower in organic anions than NO(3) (-)-fed plants, but had equal concentrations in shoots and roots. Xylem and phloem saps were collected from plants exposed to both N sources and analyzed for all major contributing ionic and nitrogenous compounds. The results obtained were used to assist in interpreting the ion uptake, assimilation, and accumulation data in terms of shoot/root pH regulation and cycling of nutrients.

Journal Article↗
PubMed1987

Lectin affinity high-performance liquid chromatography. Interactions of N-glycanase-released oligosaccharides with Ricinus communis agglutinin I and Ricinus communis agglutinin II.

The structural determinants required for interaction of oligosaccharides with Ricinus communis agglutinin I (RCAI) and Ricinus communis agglutinin II (RCAII) have been studied by lectin affinity high-performance liquid chromatography (HPLC). Homogeneous oligosaccharides of known structure, purified following release from Asn with N-glycanase and reduction with NaBH4, were tested for their ability to interact with columns of silica-bound RCAI and RCAII. The characteristic elution position obtained for each oligosaccharide was reproducible and correlated with specific structural features. RCAI binds oligosaccharides bearing terminal beta 1,4-linked Gal but not those containing terminal beta 1,4-linked GalNAc. In contrast, RCAII binds structures with either terminal beta 1,4-linked Gal or beta 1,4-linked GalNAc. Both lectins display a greater affinity for structures with terminal beta 1,4-rather than beta 1,3-linked Gal, although RCAII interacts more strongly than RCAI with oligosaccharides containing terminal beta 1,3-linked Gal. Whereas terminal alpha 2,6-linked sialic acid partially inhibits oligosaccharide-RCAI interaction, terminal alpha 2,3-linked sialic acid abolishes interaction with the lectin. In contrast, alpha 2,3- and alpha 2,6-linked sialic acid equally inhibit but do not abolish oligosaccharide interaction with RCAII. RCAI and RCAII discriminate between N-acetyllactosamine-type branches arising from different core Man residues of dibranched complex-type oligosaccharides; RCAI has a preference for the branch attached to the alpha 1,3-linked core Man and RCAII has a preference for the branch attached to the alpha 1,6-linked core Man. RCAII but not RCAI interacts with certain di- and tribranched oligosaccharides devoid of either Gal or GalNAc but bearing terminal GlcNAc, indicating an important role for GlcNAc in RCAII interaction. These findings suggest that N-acetyllactosamine is the primary feature required for oligosaccharide recognition by both RCAI and RCAII but that lectin interaction is strongly modulated by other structural features. Thus, the oligosaccharide specificities of RCAI and RCAII are distinct, depending on many different structural features including terminal sugar moieties, peripheral branching pattern, and sugar linkages.

Carbohydrate Conformation↗
PubMed1979

Effect of sulfhydryl reagents and protease inhibitors on sodium dodecyl sulfate-heat induced dissociation of Ricinus communis agglutinin.

Ricinus communis agglutinin dissociated to lower molecular weight forms when heated in sodium dodecyl sulfate in the absence of reducing agents, while ricin was little affected by such treatment. The data suggest that strong noncovalent bonds hold together two A-B heterodimers in the Ricinus communis agglutinin tetramer. Protease inhibitors such as diisopropylfluorophosphate, phenylmethansefulonyl fluoride, and EDTA, did not prevent the sodium dodecyl sulfate-heat induced dissociation; however, sulfhydryl specific reagents (N-ethylmaleimide, 5,5'-dithiobis (2-nitrobenzoic acid) and p-chloromercuribenzoate) were effective. Titration of the lectins in sodium dodecyl sulfate indicated that ricin contains one sulfhydryl and Ricinus communis agglutinin four sulfhydryl groups, none of which react in the presence of 8 M urea. The sulfhydryl groups that could be titrated in the intact proteins in sodium dodecyl sulfate were on the A chains.

Lectins↗
PubMed1978

Extraction and partial purification of ricin from Ricinus communis L.

Ricinus communis L., usually cultivated for production of oil, has some use in medicine, cosmetic industries and as motor oil. The defatted seed meal is very toxic, and can not be used as human or animal food. This study undertook extraction and identification of ricin, a toxalbumine, from Iranian Ricinus communis L. Ricin, was extracted from the seeds using dilute acid solution, salted out with ammonium sulfate, and purified by Sephadex G - 75 and DEAE - cellulose column chromatography. Disc electrophoresis showed the degree of the purification. Ricin is an anti-tumor and allergenic compound. It is also useful in biochemical research in gene control and protein systhesis.

Animals↗
PubMed1997

Changes in late-embryogenesis-abundant (LEA) messenger RNAs and dehydrins during maturation and premature drying of Ricinus communis L. seeds.

In Ricinus communis L. (castor bean) endosperms, two classes of Late Embryogenesis Abundant (Lea) transcripts were first detected during mid-development (at 30-35 days after pollination, DAP) and peaked at 50 DAP, just prior to the onset of desiccation. Most of the Class I mRNAs declined substantially during desiccation itself; Class II mRNAs remained abundant in the mature dry (60 DAP) seed. Following imbibition, all Lea mRNAs abundant in the mature dry seed declined rapidly (within 5-24 h). Premature drying of developing 35-DAP seeds resulted in the loss of storage-protein mRNAs (Leg B Mat I); following rehydration, mRNAs encoding post-germinative proteins (Germ D91, D30 and D38) increased in the endosperm. The Lea mRNAs present in the developing fresh seed at 35 DAP were preserved, but did not increase in response to premature desiccation; upon rehydration these Lea mRNAs declined within 5 h. During seed development, substantial changes occurred in the synthesis of a subset of LEA proteins referred to as "dehydrins'; in particular, new dehydrin polypeptides were induced between 40 and 60 DAP. Such proteins were not as evident in prematurely dried endosperms. In contrast to the rapid loss of Lea mRNAs during germination, many of the dehydrin proteins abundant in the dried seed persisted following imbibition or rehydration.

Ricinus communis↗
PubMed1977

Affinity of bronchial secretion glycoproteins and cells of human bronchial mucosa for Ricinus communis lectins.

The coupling of Ricinus communis lectins to Sephadex G 25 was used in order to study mucins and other glycoproteins from human bronchial secretion. The major part of human bronchial mucins and other glycoproteins such as immunoglobulins A, bronchotransferrin and alpha1-antichymotrypsin were isolated by this procedure. A parallel study of human bronchial mucosa was achieved with peroxidase labeled Ricinus communis lectins; this study characterized goblet cells and mucous cells which contain mucins, and serous cells which are involved in the synthesis or the secretion of the other glycoproteins.

Amino Acids↗
PubMed1982

Chemical modification studies on Ricinus communis (Castor Bean) agglutinin.

Ricinus communis agglutinin was subjected to various chemical treatments and the effect on its hemagglutinating and saccharide-binding properties was studied. Acetylation, succinylation and citraconylation led to a complete loss in the activity of the agglutinin, whereas reductive methylation had no effect on the activity, showing that charged amino groups were involved in the hemagglutinating and saccharide-binding activity of Ricinus agglutinin. Modification of tryptophyl, arginyl and carboxyl-group-containing residues did not lead to any loss in the activity of the agglutinin. Acetylation of tyrosyl groups with N-acetylimidazole strongly reduced the hemagglutinating and saccharide-binding property of Ricinus agglutinin. The loss in activity was restored on deacetylation of the tyrosyl groups. Modification of tyrosyl residues also led to a change in the immunological properties of the agglutinin. The initial rate of modification of tyrosyl and amino groups and the concomitant loss of activity was reduced in the presence of lactose.

2-Hydroxy-5-nitrobenzyl Bromide↗
PubMed1977

The toxicity and antitumor activity of three individual fractions of lectins from Ricinus communis seeds.

Lectins from Ricinus communis seeds (RCL) have been resolved into three electrophoretically distinct fractions (alpha-RCL, beta-RCL, psi-RCL) by ion exchange chromatography on Watman CM-32 cellulose. The toxicity to mice and antitumor activity against murine lymphoma NK/Ly of pure fractions were compared. Optimal effect was achieved with alpha-RCL, Which possessed the lowest toxicity (1000 micron g/kg) and significant antitumor activity (63% inhibition of tumor growth).

Animals↗
PubMed2000

Monitoring of urban traffic emissions using some physiological indicators in Ricinus communis L. plants.

Plants of Ricinus communis L. in the city of Porto Alegre, in southern Brazil, were exposed to urban traffic exhaust emissions for 5 months and compared with controls kept at a site essentially free of direct motor vehicle emissions. No symptomatic visible injuries were observed, but significant differences could be measured in growth, enzymatic activities of total peroxidase and nitrate reductase, chlorophyll content, leaf buffering capacity, and N contents in leaves. Additionally, these data were compared with results from fumigation experiments under controlled conditions. The study showed that some physiological parameters in R. communis L. plants could be used as an appropriate bioindicator system for urban traffic contamination, and therefore it is recommended that dose-response relationships should be developed.

Air Pollutants↗
PubMed1992

Biological activity of recombinant Ricinus communis agglutinin A chain produced in Escherichia coli.

DNA encoding Ricinus communis agglutinin A chain was ligated into the E. coli expression vector pDS 5/3. Induced E. coli 71.18 cells which had been transformed with this plasmid express Ricinus communis agglutinin A chain in a soluble and biologically active form. Recombinant Ricinus communis agglutinin A chain had ribosomal RNA N-glycosidase activity and was approximately 10-fold less active than ricin A chain in a cell-free protein synthesis inhibition assay.

Cell-Free System↗
PubMed2003

Antifertility effects of Ricinus communis (Linn) on rats.

The antifertility effects of 50% ethanol extracts of Ricinus communis have been studied in male rats. There was a drastic reduction in the epididymal sperm counts. Alteration in the motility, mode of movement and morphology of the sperms were observed. Reductions in the fructose and testosterone levels were suggestive of reduced reproductive performance. Reversibility tests showed that the antifertility effect of Ricinus communis was completely reversible on withdrawal of the drug. The ethanol extracts of Ricinus communis did not cause any hepatotoxicity since the hepatic GOT and GPT levels were unaltered.

Acid Phosphatase↗
PubMedDate not supplied

Naturally occurring and experimentally induced castor bean (Ricinus communis) poisoning in ducks.

Castor bean (Ricinus communis) poisoning accounted for the death of several thousand ducks in the Texas panhandle in the fall and winter months of 1969-1971. Signs of intoxication resembled those of botulism, except for mucoid, blood-tinged excreta. The most common lesions were severe fatty change in the liver, widely distributed internal petechial hemorrhages or ecchymoses, and catarrhal enteritis. Nearly intact castor beans were found in the stomach of one duck during field necropsy. Fragments of seed coat resembling castor bean were found in the stomachs of 10 of 14 ducks examined in the laboratory. Clinical signs and postmortem lesions observed in wild ducks were induced experimentally in mallards (Anas platyrhynchos) by force-feeding intact castor beans. Toxicity titrations were erratic, but the LD50 appeared to be between three and four seeds. The mouse toxicity test, used to detect Clostridium botulinum toxin in the blood serum of intoxicated ducks, was negative in every case. Hemagglutination and precipitin tests generally failed to detect castor bean in extracts of excreta or intestinal contents of experimentally intoxicated ducks.

Animals↗
PubMed1985

Purification and characterization of Ricinus communis invertase.

An invertase from Ricinus communis leaves was purified 4,400-fold. The preparation was homogeneous by criteria of gel electrophoresis, gel permeation, adsorption, and ionic exchange chromatography. One optimum pH at 3.5 was observed with crude invertase; however, purified preparations showed two optima, at pH 3.5 and 5.5. Addition of bovine serum albumin restored one maximum at pH 3.5 and elicited a 30% activation of the invertase. The effect was caused by many other proteins and by heparin, dextran sulfate, and polyvinylpyrrolidone. Fructose, fructose 1,6-diphosphate, maleic, trans-aconitic, malic, and ascorbic acids were simple competitive inhibitors of the purified enzyme. Glucose was a noncompetitive inhibitor. The activation by proteins suppressed these inhibitory effects. The minimum concentration of activator necessary to reach the maximal activation or "point of optimal activation" was always reached at a concentration of 1 X 10(-6) M, independently of the nature of the activator, when 8.6 X 10(-12) mol of enzyme were used. Apparent molecular weight determinations of the enzyme in the presence and absence of activator and molecular weight determinations based on determinations of the point of optimal activation suggested that the purified enzyme is a heptamer (Mr of 77,900, Stokes radius 32 A, frictional ration f/fo 1.1, partial specific volume 0.749 ml/g) and that the activated form is a trimer consisting of two enzyme subunits and one activator molecule. The activation was lost by dilution of the trimer. The enzyme subunit, as isolated by gel filtration in the presence of sodium dodecyl sulfate (Mr 11,000) was inactive but quickly regained activity upon removal of sodium dodecyl sulfate.

Enzyme Activation↗
PubMed2005

Recognition factors of Ricinus communis agglutinin 1 (RCA(1)).

Ricinus communis agglutinin (RCA1) is one of the most important applied lectins that has been widely used as a tool to study cell surfaces and to purify glycans. Although the carbohydrate specificity of RCA1 has been described, the information obtained was mainly focused on inhibition of simple Galbeta1-related oligosaccharides and simple clusters. Here, all possible recognition factors of RCA1 of glycan binding were examined by enzyme-linked lectinosorbent (ELLSA) and inhibition assays, using known mammalian Gal/GalNAc carbohydrate structural units and natural polyvalent glycans. Among the glycoproteins (gps) tested and expressed as 50% nanogram inhibition, the high-density polyvalent Galbeta1-4GlcNAc (II) glycotopes occurring in natural gps, such as Pneumococcus type 14 capsular polysaccharide which is composed of repeating poly II residues, resulted in 9.0 x 10(4), 1.5 x 10(5), 2.3 x 10(4) and 2.1 x 10(4)-fold higher affinities to RCA1 than the monomeric Gal, linear I/II and Tri-antennary-II (Tri-II). Of the ligands tested and expressed as nanomoles of 50% inhibition, Tri-II was the best, being about 2, 4, 25.6 and 33.3 times better inhibitor than Di-II, II, I (Galbeta1-3GlcNAc) and Gal, respectively. From the results of this study, it is concluded that: (a) Galbeta1-4GlcNAc and other Galbeta1-related oligosaccharides are essential for lectin binding and their polyvalent form in macromolecules should be the most important recognition factor for RCA1; (b) the combining site of RCA1 may be a groove type, recognizing Galbeta1-4GlcNAc (II) as the major binding site; (c) its combining size may be large enough to accommodate a tetrasaccharide of beta-anomeric Gal at the non-reducing end and most complementary to human blood group I Ma active trisaccharide (Galbeta1-4GlcNAcbeta1-6Gal) and lacto-N-neotetraose (Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc); (d) RCA1 has a preference for the beta-anomer of Gal oligosaccharides with a Galbeta1-4 linkage > Galbeta1-6 > or = Galbeta1-3; (e) configuration of carbon-2, -3 -4 and -6 in Gal are essential for binding; (f) hydrophobic interaction in the vicinity of the binding site useful for sugar accommodation increases affinity. These results should be helpful for understanding the functional role of RCA1 and for characterizing glycotopes of mammalian complex carbohydrates.

Blood Group Antigens↗
PubMed1979

Binding of Ricinus communis agglutinin to the mitochondrial inner membrane as an artifact during preparation.

Endosperm from Ricinus communis was homogenized in the presence of 3H-labelled Ricinus communis agglutinin, with or without addition of lactose. In preparations without the binding-specific sugar the subfraction containing the mitochondrial inner membrane contained sufficient labelled agglutinin to account for the agglutinin reported to be associated with this membrane.

Ricinus communis↗
PubMed1984

Nature of the interaction between Ricinus communis agglutinin and blood cells.

Binding of Ricinus communis agglutinin (RCA 120) to carbohydrate receptors of human lymphocytes and erythrocytes is enthalpically driven. As in the case of simple saccharides, the delta S contribution is always unfavorable to the interaction. This result is different from that observed for other lectins and might indicate that hydrophobic interactions do not play a dominant role in binding of RCA 120 to cell surfaces.

ABO Blood-Group System↗
PubMed1987

Ricinus communis agglutinin II-reactive glycoproteins from the ascites of patients with hepatocellular carcinoma and their use in enzyme-linked immunosorbent assay.

Ricinus communis agglutinin II-reactive glycoproteins from the ascites of patients with hepatocellular carcinoma were prepared using lectin affinity chromatography. Normal serum- and cirrhotic ascites-components were removed by columns with immobilized antibodies against them. Ricinus communis agglutinin II-reactive glycoproteins thus obtained were supposed to be hepatocellular carcinoma-associated and less than 0.1% of the protein in the starting material. Polyacrylamide gel electrophoresis of these glycoproteins revealed more than 10 major polypeptides with molecular weights ranging from 20K to 200K daltons. The rabbit antiserum raised against them reacted with at least three components of 45, 52 and 55K daltons. The serum level of this antibody-reactive glycoproteins was assessed by an enzyme-linked immunosorbent assay. It was elevated in 91% of cases of hepatocellular carcinoma, 70% of cases of other gastrointestinal carcinoma, 88% of cases of liver cirrhosis, 55% of cases of chronic hepatitis, and 25% of cases of acute hepatitis. The mean value of hepatocellular carcinoma was significantly greater than those of other groups. These results suggest that some of Ricinus communis agglutinin II-reactive glycoproteins in hepatocellular carcinoma patients may be cancer-associated glycoproteins and that their serum levels are increased in hepatocellular carcinoma patients.

Ascites↗