Global Gene Expression of Seed Coat Tissues Reveals a Potential Mechanism of Regulating Seed Size Formation in Castor Bean.

The physiological and molecular basis of seed size formation is complex, and the development of seed coat (derived from integument cells) might be a critical factor that determines seed size formation for many endospermic seeds. Castor bean (Ricinus communis L.), a model system of studying seed biology, has large and persistent endosperm with a hard seed coat at maturity. Here, we investigated the potential molecular mechanisms underlying seed size formation in castor bean by comparing the difference between global gene expression within developing seed coat tissues between the large-seed ZB107 and small-seed ZB306. First, we observed the cell size of seed coat and concluded that the large seed coat area of ZB107 resulted from more cell numbers (rather than cell size). Furthermore, we found that the lignin proportion of seed coat was higher in ZB306. An investigation into global gene expression of developing seed coat tissues revealed that 815 genes were up-regulated and 813 were down-regulated in ZB306 relative to ZB107. Interestingly, we found that many genes involved in regulating cell division were up-regulated in ZB107, whereas many genes involved in regulating lignin biosynthesis (including several NAC members, as well as MYB46/83 and MYB58/63) and in mediating programmed cell death (such as CysEP1 and ßVPE) were up-regulated in ZB306. Furthermore, the expression patterns of the genes mentioned above indicated that the lignification of seed coat tissues was enhanced and occurred earlier in the developing seeds of ZB306. Taken together, we tentatively proposed a potential scenario for explaining the molecular mechanisms of seed coat governing seed size formation in castor bean by increasing the cell number and delaying the onset of lignification in seed coat tissues in large-seed ZB107. This study not only presents new information for possible modulation of seed coat related genes to improve castor seed yield, but also provides new insights into understanding the molecular basis of seed size formation in endospermic seeds with hard seed coat.

A sensitive and low background fluorescent sensing strategy based on g-C3N4-MnO2 sandwich nanocomposite and liposome amplification for ricin detection.

Ricin is an extremely potent ribosome-inactivating protein and serves as a likely food biocontaminant or biological weapon. Thus, simple, sensitive and accurate analytical assays capable of detecting ricin are urgently needed to be established. Herein, we present a novel method for ricin B-chain (RTB) detection by using two materials: (a) a highly efficient hybrid probe that was formed by linking a glucose oxidase (GOD)-encapsulated liposome (GOD-L) to magnetic beads (MBs) through hybridization between an aptamer and a blocker and (b) a new low-background g-C3N4-MnO2 sandwich nanocomposite that exhibits fluorescence resonance energy transfer (FRET) between the g-C3N4 nanosheet and MnO2. In the presence of RTB, the strong binding between RTB and the aptamer can release the blocker-linked liposome from the surface of the MBs. After magnetic separation, the decomposed liposome can release GOD to catalyze the oxidation of glucose, generating a certain amount of H2O2. Then, H2O2 can reduce MnO2 of the g-C3N4-MnO2 nanocomposite to Mn2+, which leads to the elimination of FRET. Thus, the fluorescence of the g-C3N4 nanosheet will be turned on. Because of the excellent signal amplification ability of liposome and the characteristic highly sensitive response of the g-C3N4-MnO2 nanocomposite toward H2O2, RTB could be detected sensitively based on the significantly enhanced fluorescent intensity. The linear range of detection was from 0.25 µg mL-1 to 50 µg mL-1 and the limit of detection (LOD) was 190 ng mL-1. Moreover, the proposed assay was successfully applied in the detection of the entire ricin toxin content in a castor seed.

Turnover time of the non-structural carbohydrate pool influences δ18O of leaf cellulose.

Certainty regarding the degree to which organic molecules exchange oxygen with local water during plant cellulose synthesis (p(ex)) is necessary for cellulose oxygen isotope (δ(18)O(cell))-based applications in environmental and ecological studies. However, the currently accepted notion that p(ex) is a constant of ca. 0.42 appears inconsistent with biochemical theory, which predicts that marked variation may be present in p(ex), in relation to variation in the turnover time (τ) of the carbohydrate pool available for cellulose synthesis. The above prediction was tested in the present study with the analysis of data collected from leaves of Ricinus communis grown in controlled environmental conditions that varied in light intensity and vapour pressure deficit. The results revealed the existence of considerable variation in both p(ex) and τ across plants in the various growth environments. Moreover, despite uncertainties in estimates of the proportion of source water in the synthesis water (p(x)) and of the biochemical fractionation factor (ε(o)), our experiment yielded strong evidence that p(ex) exhibits a significant, positive relationship with τ, consistent with biochemical theory. The observed variation in p(ex) in association with τ has important implications for the interpretation of δ(18)O(cell) data in environmental/ecological studies.

Castor (Ricinus communis L.) differential cell cycle and metabolism reactivation, germinability, and seedling performance under NaCl and PEG osmoticum: Stress tolerance related to genotype-preestablished superoxide dismutase activity.

Castor (Ricinus communis) is a relevant industrial oilseed feedstock for many industrial applications, being globally mainly cultivated by smallholder farmers in semiarid areas, where abiotic stresses predominate. Therefore, susceptible to generating reactive oxygen species (ROS) and subsequent oxidative stress, compromising cell metabolism upon seed imbibition and germination, seedling and crop establishment, and yield. The present study evaluated the consequences of water restriction by Polyethylene glycol (PEG) and Sodium chloride (NaCl) on cell cycle and metabolism reactivation on germinability, seedling growth, and vigor parameters in 2 commercial castor genotypes (Nordestina and Paraguaçu). PEG water restriction inhibited germination completely at -0.23 MPa or higher, presumably due to reduced oxygen availability. The restrictive effects of NaCl saline stress on germination were observed only from -0.46 MPa onwards, affecting dry mass accumulation and the production of normal seedlings. In general, superoxide dismutase (SOD) activity increased in NaCl -0.23 MPa, whereas its modulation during the onset of imbibition (24h) seemed to depend on its initial levels in dry seeds in a genotype-specific manner, therefore, resulting in the higher stress tolerance of Nordestina compared to Paraguaçu. Overall, results show that Castor germination and seedling development are more sensitive to the restrictive effects of PEG than NaCl at similar osmotic potentials, contributing to a better understanding of the responses to water restriction stresses by different Castor genotypes. Ultimately, SOD may constitute a potential marker for characterizing castor genotypes in stressful situations during germination, early seedling, and crop establishment, and a target for breeding for Castor-improved stress tolerance.

Isolation of cellulolytic fungi from waste of castor (Ricinus communis L.).

This is the first report of isolation of fungi present in fatty and defatted castor bean meal as well as the first of crop's selection to test the cellulolytic potential, in order to verify the diversity and potential of cellulolytic fungi in castor bean waste (Ricinus communis L.). For the screening on solid medium, it was used carboxymethylcellulose (CMC) as the sole carbon source. The microcrystalline cellulose (Avicel) was used as a substrate for submerged fermentation for production of cellobiohydrolase (FPase) and the CMC to produce endoglucanases (CMCase) and ß-glycosidases (BG). 189 cultures of fungi were isolated, including 40 species of filamentous fungi and three yeasts. The Aspergillus was the most frequent found genus. Regarding the distribution of isolated species from defatted castor bean meal, the A. niger was the most frequent one; and within the fatty castor bean meal, the Emericela variecolor prevailed among other species. Among the 67 fungal cultures tested in the initial screening on solid media to assess the cellulolytic potential, 54 disclosed Cellulolytic Index (CI) ranging from 1.04 to 6.00 mm. The isolates were selected for enzyme production in liquid medium with values above 2.0 CI. They were obtained with A. japonicus URM5620 FPase activity (4.99 U/ml) and BG (0.05 U/ml), and Rhodotorula glutinis URM5724 activity of CMCase 3.58 U/ml. These cases occurred after 168 h of submersion for both species of fungi. In our study, we could conclude that the castor bean is a promising source of fungi capable of producing cellulolytic enzymes.

Castor bean (Ricinus communis) toxicosis in a sheep flock.

This paper describes clinical, laboratory and pathological findings of sheep, which is intoxicated with castor bean. The source of intoxication was a miscellaneous garden waste. Forty-five animals showed clinical toxicosis and 17 died. The clinical signs included weakness, salivation, profuse watery diarrhoea, dehydration, mydriasis, teeth grinding, hypothermia and recumbency. The most significant haematological and biochemical findings were a high haematocrit, high concentration of serum BUN, creatinine and phosphorus and high activity of serum CK and AST. Pathology revealed severe gastroenteritis, cardiac haemorrhage and necrosis, hepatic necrosis and acute tubular necrosis in kidneys. Treatment included symptomatic and supportive care with fluid therapy and cathartic administration.

Leucoplast Isolation and Subfractionation.

Leucoplasts are colorless plastids of nonphotosynthetic plant tissues that support a variety of anabolic roles, particularly the biosynthesis of long-chain fatty acids in storage tissues of developing oil seeds. They also perform other important metabolic functions including the biosynthesis of amino acids and tetrapyrrole compounds. Leucoplasts use a complex set of membrane carriers and channels to actively translocate nuclear-encoded precursor proteins from the cytosol, while exchanging various metabolites with the cytosol. Leucoplast purification is a necessary prerequisite for detailed studies of their soluble (stromal) and membrane (envelope) (phospho)proteomes, as well as for achieving a detailed understanding of their metabolic capabilities, transport processes, and biogenesis. This chapter describes protocols for leucoplast purification from endosperm of developing castor oil seeds, and their subsequent subfractionation into envelope membrane and soluble stromal compartments for biochemical analysis.

Membrane fusion mediated by ricin and viscumin.

The ribosome inactivating plant proteins (RIPs) ricin and viscumin but not Ricinus communis agglutinin are able induce vesicle-vesicle fusion. A model is suggested in which the toxicity of the RIPs is partially determined by their fusogenicity. Herein, fusion is hypothesized to allow the RIPs to leak across endocytic vesicles to approve their access to cytoplasmic ribosomes.

Defining carbohydrate specificity of Ricinus communis agglutinin as Gal beta 1-->4GlcNAc (II) > Gal beta 1-->3GlcNAc (I) > Gal alpha 1-->3Gal (B) > Gal beta 1-->3GalNAc (T).

To define carbohydrate specificity of Ricinus communis agglutinin (RCA1), the combining site of RCA1 was further characterized by quantitative precipitin (QPA) and precipitin-inhibition assays (QPIA). Among the oligosaccharides tested for QPIA, Gal beta 1-->4GlcNAc (II, human blood group type II precursor sequence) was found to be 7.1 times more active than Gal beta 1-->3GalNAc (T, Thomsen-Friedenreich sequence) and about 1.7 times more active than the other three disaccharides tested--Gal beta 1-->4Man, Gal beta 1-->3DAra and Gal beta 1-->6GalNAc. Gal alpha 1-->4Gal, the receptor of the uropathogenic E. coli ligand was 3.6 times less active than the II sequence. These results indicate that the beta 1-->4 linkage of the terminal Gal to subterminal GlcNAc is important as this beta 1-->4GlcNAc sequence is at least 1.6 times more active than other types of disaccharides. Among the glycoproteins examined for QPA, native and desialized bovine submandibular glycoproteins, native and desialized human plasma alpha 1-acid glycoproteins, as well as crude hog stomach mucin and its three mild acid hydrolyzed products reacted well with the lectin. These glycoproteins precipitated over 75% of the lectin nitrogen added indicating that RCA1 has the ability to recognize Gal beta 1-->4/3GlcNAc and/or the related residues at the non-reducing ends and at positions in the interior of the chains. However, Tn (GalNAc alpha 1-->Ser/Thr sequence) rich glycoproteins such as desialized ovine submandibular glycoprotein and desialized armadillo salivary glycoprotein, in which over 90% of the carbohydrate side chains are Tn determinants with none or only a trace of I/II or T determinants, precipitated poorly with RCA1. From the present and previous results obtained, the carbohydrate specificity of RCA1 can be constructed and summarized in decreasing order by lectin determinants as follows: II (Gal beta 1-->4GlcNAc) > I (Gal beta 1-->3GlcNAc) > E (Gal alpha 1-->4Gal) and B (Gal alpha 1-->3Gal) > T (Gal beta 1-->3GalNAc), while Tn (GalNAc alpha 1-->Ser/Thr) is a poor inhibitor.

Synthesis and carbohydrate-binding activity of poly(ethyleneglycol)-Ricinus communis agglutinin I conjugates.

The synthesis of poly(ethyleneglycol) (PEG)-lectin conjugates was investigated to provide new reagents for evaluation as biological response modifiers. PEG was activated with 1,1'-carbonyldiimidazole (CDI), followed by conjugation with Ricinus communis I (RCAI) lectin. The resulting conjugates were heterodisperse with respect to molecular weight. Carbohydrate-binding activity was retained. The conjugates were separated by affinity chromatography into fractions differing in apparent carbohydrate-binding affinity. Conjugation of RCAI with PEG 4 (mol.wt. 3350) or PEG 6 (mol.wt. 8000) appeared to provide less hindrance of the lectin binding site compared to conjugates prepared with PEG 20 (mol.wt. 20,000). Results of free amine assays indicated that higher ratios of PEG to RCAI in conjugates correlated with loss of low-affinity binding and retention of high-affinity binding. The data showed the feasibility of preparing PEG-lectin conjugates for in vivo use.

Histologic and histometric evaluation of rat alveolar wound healing around polyurethane resin implants.

The biocompatibility of polyurethane resin-implants derived from castor bean (Ricinus communis) was analyzed in the rat dental alveolus. Histometric evaluation of trial areas adjacent to the implants showed, by week 1, the polymer granules encircled by a conspicuous capsule and surrounded by immature connective tissue. By weeks 2 and 3, the implants were surrounded by less prominent fibrous capsules and most of the tested area was occupied by mature trabecular bone. By week 6, the fibrous capsule was thinner and the tested area was almost totally covered with bone, which in several places was in close contact with the implants. The results suggest that the material is compatible, as it was progressively integrated into alveolar bone in the wound-healing process.

Biocompatibility of the polyurethane resin of the castor bean inserted into the alveolar bone of the dog.

The biocompability of the polyurethane resin of the castor bean (Ricinus vulgaris) was studied following its insertion into the alveolar bone of dogs, after extraction of their premolar teeth. The resin was left to polymerise in the dental alveolus. Excess of material due to polymerisation was removed and polishing was employed to smooth and adapt the occlusal surface to the margins of the alveolar bone. This allowed a perfect suture of the mucosa together with the periosteum. The resin remained in the dental alveolus for 90 days. It was observed that the polyurethane was replaced by osteoid and bone tissues and no immune or inflammatory reactions were detected. There has been work on and discussion about the use of the polyurethane in grafts, prostheses and orthoses. Attention was paid to all the surgical steps, in particular the preservation of the periosteal integrity. Further research is being followed in our Department in order to test the biocompatibility of the material presented in this paper when used together with metallic or ceramic implants.

Seeds' physicochemical traits and mucilage protection against aluminum effect during germination and root elongation as important factors in a biofuel seed crop (Ricinus communis).

We determined the length, volume, dry biomass, and density in seeds of five castor bean cultivars and verified notable physicochemical trait differences. Seeds were then subjected to different toxic aluminum (Al) concentrations to evaluate germination, relative root elongation, and the role of root apices' rhizosphere mucilage layer. Seeds' physicochemical traits were associated with Al toxicity responses, and the absence of Al in cotyledons near to the embryo was revealed by Al-hematoxylin staining, indicating that Al did not induce significant germination reduction rates between cultivars. However, in the more sensitive cultivar, Al was found around the embryo, contributing to subsequent growth inhibition. After this, to investigate the role of mucilage in Al tolerance, an assay was conducted using NH4Cl to remove root mucilage before or after exposure to different Al concentrations. Sequentially, the roots were stained with hematoxylin and a quantitative analysis of staining intensity was obtained. These results revealed the significant contribution of the mucilage layer to Al toxicity responses in castor bean seedlings. Root growth elongation under Al toxicity confirmed the role of the mucilage layer, which jointly indicated the differential Al tolerance between cultivars and an efficient Al-exclusion mechanism in the tolerant cultivar.

Use of lactose against the deadly biological toxin ricin.

Developing a technology for detecting and decontaminating biological toxins is needed. Ricin from Ricinus communis is a highly poisonous toxin; it was formerly used for an assassination in London and in postal attacks in the United States. Ricin is readily available from castor beans and could be used as a biological agent. We propose using glycotechnology against the illegal use of ricin. Lactose (a natural ligand of this toxin) was incorporated into polyacrylamide-based glycopolymers at variable sugar densities (18-100%) and evaluated with surface plasmon resonance (SPR) spectroscopy and the real agent, ricin. Glycopolymers (18-65% lactose densities) effectively interfered with the toxin-lactoside adhesion event (>99% efficiency within 20 min). This supported the notion of using the mammary sugar lactose against a deadly biological toxin.

Dimensional alterations and solubility of new endodontic sealers.

This study evaluated the dimensional alterations and the solubility of two experimental endodontic sealers based on Copaifera multijuga oil-resin (Biosealer) and castor oil bean cement (Poliquil), maintained in different storage solutions. Twenty specimens (3 mm diameter and 2 mm height) of each sealer were assigned to 2 groups (n=10) according to the storage solution: simulated tissue fluid (STF) or distilled water (DW). The specimens were stored in these solutions during 90 days, being removed every 30 days for weighting. The solutions were renewed every 15 days. The results were subjected to statistical analysis by Dunn's and Mann-Whitney tests (a=0.05). The solubility of Poliquil was higher in STF (38.4 ± 36.0) than in DW (28.4 ± 15.0), while Biosealer showed higher solubility in DW (34.61 ± 6.0) than in STF (18.59 ± 8.0). The storage solution influenced the behavior of sealers in relation to the weight variation (p=0.0001). Poliquil presented higher variation of weight independent of the solution (p=0.239). Biosealer also presented higher variation of weight regardless of the solution (p=0.0001). The solubility of Biosealer was different from that of Poliquil, but both sealers showed low solubility in STF. Under the tested conditions, neither of the materials were according to the ADA'S specification.

Ricinus communis biocompatibility histological study in the nose of Cebus apella monkeys.

UNLABELLED: Bone tissue lesions can be caused by congenital and acquired factors, and result in nasal deformities with cosmetic and functional repercussion. Surgical treatment in these cases frequently requires complex reconstructions and the use of biomaterials. The polyurethane derived from castor beans (Ricinus communis) has a favorable formulation in terms of ease of processing, flexibility, no emission of toxic vapors and low cost. Nonetheless, despite favorable results, studies about the use of castor beam polymer (Ricinus communis) assessing tissue reaction on the nasal dorsum are still missing in the literature. AIM: the goal of the present investigation is to histologically assess the Ricinus communis polymer implant biocompatibility with the nasal dorsum. STUDY DESIGN: experimental. MATERIALS AND METHODS: we used four Cebus appela monkeys, in which we created a nasal dorsal defect in all the animals and there we placed the aforementioned implant. The animals were sacrificed 270 days after surgery and the samples were submitted to histological study. RESULTS: in the histology analysis we did not observe the presence of foreign body granulomas or phagocytic cells. We also observed a progressive bone formation and maturation. CONCLUSION: macroscopic and microscopic results showed that the castor oil polymer implant was biocompatible.

Estudo histomorfométrico do processo de cicatrização óssea em defeitos cirúrgicos de tamanho crítico em calvárias de ratos preenchidos com polímero de mamona / Histomorphometric study of bone healing process in surgical defects of critical size rat calvarial filled with castor oil polymer

Introdução: O objetivo do presente estudo foi avaliar histomorfometricamente o comportamento do polímero de mamona durante o processo de cicatrização de defeitos de tamanho crítico preparados em calvárias de ratos. Materiais e Métodos: Vinte animais foram submetidos a um procedimento cirúrgico que consistiu em se realizar na calvária de cada animal um defeito crítico de 8 mm de diâmetro com uma broca trefina. Os ratos foram divididos em dois grupos de acordo com os seguintes procedimentos: Grupo C, não receberam nenhum tratamento local e o defeito ósseo foi preenchido com coágulo sanguíneo; Grupo M, o defeito ósseo foi preenchido com partículas de polímero de mamona. Os animais foram sacrificados 180 dias após os procedimentos cirúrgicos. Após os procedimentos laboratoriais de rotina as peças foram submetidas à análise histomorfométrica. Resultados: Nos animais do Grupo C o tecido ósseo neoformado mostrou-se bem desenvolvido, com áreas adjacentes de matriz osteóide rica em osteoblastos, e restrito às proximidades das bordas do defeito. Nos animais do Grupo M observou-se tecido ósseo lamelar neoformado restrito às proximidades das bordas do defeito e partículas de Polímero de Mamona distribuídas ao longo do defeito. Houve uma maior porcentagem de área de osso neoformado estatisticamente significante nos animais do Grupo C comparado aos animais do Grupo M. Conclusão: Dentro dos limites deste estudo pode-se concluir que o polímero de mamona apresentou-se biocompatível e manteve o espaço durante o processo de cicatrização de defeitos de tamanho crítico cirurgicamente preparadas em calvárias de ratos

Objectives: The aim of this study was to evaluate the behavior of the polymer histomorphometrically castor during the healing process of defects of critical size calvarial preparations in rats. Materials and Methods: Twenty animals underwent a surgical procedure that was to be held in the calvaria of each animal a critical defect of 8 mm in diameter with a drill trephine. The rats were divided into two groups according to the following procedures: group C received no treatment and the bone defect site was filled with blood clot, group M, the bone defect was filled with castor oil polymer particles. The animals were sacrificed 180 days after the surgical procedures. After routine laboratory procedures the specimens were subjected to analysis histomorphometric. Results: In groups C the newly formed bone tissue was well developed, with adjacent areas of osteoid matrix rich in osteoblasts, and restricted to the vicinity of the edges of the defect. In animals of group M was observed newly formed lamellar bone tissue restricted to the vicinity of the defect edges and particles of polymer Castor distributed throughout the defect. There was a higher percentage of newly formed bone area was statistically significant in group C compared to animals in group M. Conclusions: Within the limits of this study can conclude that the castor oil polymer is biocompatible and had kept the area during the healing of critical size defects in surgically prepared rat calvariae

Dimensional alterations and solubility of new endodontic sealers

This study evaluated the dimensional alterations and the solubility of two experimental endodontic sealers based on Copaifera multijuga oil-resin (Biosealer) and castor oil bean cement (Poliquil), maintained in different storage solutions. Twenty specimens (3 mm diameter and 2 mm height) of each sealer were assigned to 2 groups (n=10) according to the storage solution: simulated tissue fluid (STF) or distilled water (DW). The specimens were stored in these solutions during 90 days, being removed every 30 days for weighting. The solutions were renewed every 15 days. The results were subjected to statistical analysis by Dunn's and Mann-Whitney tests (a=0.05). The solubility of Poliquil was higher in STF (38.4 ± 36.0) than in DW (28.4 ± 15.0), while Biosealer showed higher solubility in DW (34.61 ± 6.0) than in STF (18.59 ± 8.0). The storage solution influenced the behavior of sealers in relation to the weight variation (p=0.0001). Poliquil presented higher variation of weight independent of the solution (p=0.239). Biosealer also presented higher variation of weight regardless of the solution (p=0.0001). The solubility of Biosealer was different from that of Poliquil, but both sealers showed low solubility in STF. Under the tested conditions, neither of the materials were according to the ADA'S specification.

O presente estudo avaliou a alteração dimensional e solubilidade de 2 cimentos experimentais (à base de resina do óleo de Copaíba - Biosealer e cimento do polímero da mamona - Poliquil), mantidos em diferentes meios de armazenamento. Foram confeccionados 20 espécimes de cada cimento com 3 mm de diâmetro e 2 mm de altura os quais foram divididos em 2 grupos (n=10) de acordo com o meio de armazenamento (fluido tissular simulado ou água destilada). Os espécimes foram atidos nas soluções durante 90 dias, sendo removidos a cada 30 dias para pesagem das amostras, no entanto as soluções foram trocadas a cada 15 dias. Os resultados foram submetidos aos testes de Dunn (5 por cento) e Mann-Whitney. Os meios de armazenamento causaram influência no comportamento dos cimentos em relação ao peso (p=0,0001). Poliquil apresentou alta variação de peso independente da solução (p=0,239). Biosealer também apresentou alta variação de peso independente da solução (p=0,0001). A solubilidade do Biosealer foi diferente do Poliquil, entretanto, ambos cimentos mostraram baixa solubilidade no fluido tissular simulado. Nas condições do experimento, nenhum cimento está de acordo com a especificação da ADA.

Ricinus communis agglutinin-mediated agglutination and fusion of glycolipid-containing phospholipid vesicles: effect of carbohydrate head group size, calcium ions, and spermine.

The glycolipids galactosylcerebroside (GalCer), lactosylceramide (LacCer), and trihexosylceramide (Gb3) were inserted into phospholipid vesicles, consisting of phosphatidylethanolamine and phosphatidic acid. The extent to which their carbohydrate head groups protruded beyond the vesicle surface and their interference with membrane approach were examined by determining vesicle susceptibility toward type I Ricinus communis agglutinin (RCA1) induced agglutination and Ca2+- and spermine-induced aggregation and fusion either in the presence or in the absence of the lectin. The initial agglutination rates increased in the order GalCer much less than LacCer less than Gb3, while a reversed order was obtained for Ca2+- and spermine-induced aggregation and fusion, indicating an enhanced steric interference on close approach of bilayers with increasing head group size. The lectin-mediated agglutination rates for LacCer- and Gb3-containing vesicles increased by an order of magnitude when Ca2+ was also included in the medium, at a concentration that did not induce aggregation per se. Charge neutralization could not account for this observation as the polyvalent cation spermine did not display this synergistic effect with RCA1. Addition of Ca2+ to preagglutinated vesicles substantially reduced the threshold cation concentration for fusion (micromolar vs. millimolar). Quantitatively, this concentration decreased with decreasing carbohydrate head group size, indicating that the head group protrusion determined the interbilayer distance within the vesicle aggregate. The distinct behavior of Ca2+ vs. spermine on RCA1-induced agglutination on the one hand and fusion on the other indicated that Ca2+ regulates the steric orientation of the carbohydrate head group, which appears to be related to its ability to dehydrate the bilayer. As a result, lectin agglutinability becomes enhanced while fusion will be interrupted as the interbilayer distance increases, the threshold head group size being three carbohydrate residues (Gb3). Finally, GalCer-containing vesicles were not agglutinated by RCA1 at ambient temperature, irrespective of the presence of Ca2+. Above 25 degrees C, RCA1 facilitated Ca2+-induced fusion of the vesicles, which was abolished by the haptenic sugar lactose. Since Gb3- and LacCer-containing vesicles displayed a similar behavior, a temperature-induced alteration in the supporting lipid matrix is suggested, which apparently affects lectin/glycolipid interaction.

Ricinus communis biocompatibility histological study in the nose of Cebus apella monkeys / Avaliação histológica da biocompatibilidade do polímero da mamona no dorso nasal de macacos-pregos (Cebus apella)

Bone tissue lesions can be caused by congenital and acquired factors, and result in nasal deformities with cosmetic and functional repercussion. Surgical treatment in these cases frequently requires complex reconstructions and the use of biomaterials. The polyurethane derived from castor beans (Ricinus communis) has a favorable formulation in terms of ease of processing, flexibility, no emission of toxic vapors and low cost. Nonetheless, despite favorable results, studies about the use of castor beam polymer (Ricinus communis) assessing tissue reaction on the nasal dorsum are still missing in the literature. AIM: the goal of the present investigation is to histologically assess the Ricinus communis polymer implant biocompatibility with the nasal dorsum. STUDY DESING: experimental. MATERIALS AND METHODS: we used four Cebus appela monkeys, in which we created a nasal dorsal defect in all the animals and there we placed the aforementioned implant. The animals were sacrificed 270 days after surgery and the samples were submitted to histological study. RESULTS: in the histology analysis we did not observe the presence of foreign body granulomas or phagocytic cells. We also observed a progressive bone formation and maturation. CONCLUSION: macroscopic and microscopic results showed that the castor oil polymer implant was biocompatible.

Lesões do tecido ósseo podem ser causadas por fatores congênitos e adquiridos e resultar em deformidade nasal com repercussão estética e funcional. O tratamento cirúrgico desses casos requer reconstruções complexas e frequentemente o uso de biomateriais. O poliuretano derivado do óleo da mamona apresenta uma fórmula com aspectos favoráveis de processabilidade, flexibilidade de formulação, ausência de emissão de vapores tóxicos e baixo custo. Entretanto, a despeito dos resultados favoráveis, estudos referentes ao uso do polímero de mamona, avaliando a reação tecidual no dorso nasal, ainda não foram realizados. OBJETIVO: O objetivo deste estudo consiste em avaliar histologicamente a biocompatibilidade do implante do polímero de mamona no dorso nasal. FORMA DE ESTUDO: Experimental. MATERIAL E MÉTODO: Foram utilizados quatro macacos-pregos da espécie Cebus apella. Um defeito ósseo foi realizado no osso nasal em todos os animais e colocado um implante de polímero de mamona. A eutanásia foi realizada com 270 dias de pós-operatório, e as amostras foram submetidas a estudo histológico. RESULTADOS: Na análise histológica não foi observada a presença de granuloma de corpo estranho ou células fagocitárias. Progressiva formação óssea e maturação foram observadas. CONCLUSÃO: Os resultados macroscópicos e microscópicos mostraram que o implante de polímero de mamona foi biocompatível.