Ribosome-inactivating proteins and agglutinins from callus and suspension cultures of Ricinus communis L. and Abrus precatorius L.

Plant Science ◽  
1993 ◽  
Vol 94 (1-2) ◽  
pp. 161-172 ◽  
Author(s):  
Icy D'Silva ◽  
Chelakara S. Vaidyanathan ◽  
Sunil K. Podder
1997 ◽  
Vol 17 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Carlos Hubinger Tokarnia ◽  
Jürgen Döbereiner

Cinco bovinos imunizados contra a ação tóxica das sementes de Abrus precatorius L. ("tento", "jiquiriti") não adoeceram ou somente levemente pela administração das sementes de Ricinus communis L. ("mamona"), em doses que em bovinos que antes nunca ingeriram sementes de A. precatorius ou R. communis, causaram intoxicação de intensidade de grau moderado a acentuado ou até a morte. Um sexto bovino, que não ficou bem imunizado contra a ação tóxica das sementes de A. precatorius, adoeceu em grau acentuado pela administração de dose elevada das sementes de R. communis. Já dos cinco bovinos imunizados contra a ação tóxica das sementes de R. communis quatro adoeceram em grau acentuado, oquinto em grau moderado, pela administração das sementes de A. precatorias em doses que em bovinos que antes nunca ingeriram sementes de R. communis ou A. precatorius causaram intoxicação de intensidade leve a acentuada. Estes resultados permitem concluir que bovinos imunizados contra a ação tóxica das sementes de A. precatorius são resistentes à ação tóxica das sementes de R. communis, mas que o contrário não ocorre, isto é, bovinos imunizados contra a ação tóxica das sementes de R. communis, não se mostraram protegidos contra a intoxicação por A. precatorius. Estudos anteriores por outros autores mostraram que as toxalbuminas de A. precatorius e R. communis, respectivamente abrina e ricina, são diferentes do ponto de vista antigênico. Uma explicação para a divergência desses resultados com os nossos poderia estar no fato de que no presente estudo foram usados poligástricos que receberam as sementes por via oral, enquanto que nos estudos anteriores foram usados monogástricos em que as sementes ou as toxinas foram aplicadas por via parenteral. A administração de folhas frescas ou do pericarpo do fruto de R. communis a bovinos imunizados contra a ação das sementes desta planta tiveram o mesmo efeito tóxico que em animais não imunizados, demonstrando que a imunidade conferida pela ricina não inibe a ação da ricinina, o principio tóxico das folhas e do pericarpo.


Author(s):  
Letizia Polito ◽  
Massimo Bortolotti ◽  
Maria Giulia Battelli ◽  
Giulia Calafato ◽  
Andrea Bolognesi

The castor plant (Ricinus communis L.) has been known since time immemorial in traditional medicine in the pharmacopeia of Mediterranean and eastern ancient cultures. Moreover, it is still used in folk medicine worldwide. Castor bean has been mainly recommended as anti-inflammatory, anthelmintic, anti-bacterial, laxative, abortifacient, for wounds, ulcers, and many other indications. Many cases of human intoxication occurred accidentally or voluntarily with the ingestion of castor seeds or derivatives. Ricinus toxicity depends on several molecules, among them the most important is ricin, a protein belonging to the family of ribosome-inactivating proteins. Ricin is the most studied of this category of proteins and it is also known to the general public, having been used for biocrimes in several cases. Here, the main steps of ricin research are reported with particular regards to its enzymatic activity, structure and cytotoxicity. Moreover, we discuss ricin toxicity for animals and humans, as well as the relation amongst bioterrorism and ricin and its impact on environmental toxicity. Ricin has also been of great utility to develop a number of immunotoxins specific for the elimination of unwanted cells, mainly cancer cells; some of these immunotoxins gave promising results also in clinical trials.


Toxins ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 324 ◽  
Author(s):  
Letizia Polito ◽  
Massimo Bortolotti ◽  
Maria Battelli ◽  
Giulia Calafato ◽  
Andrea Bolognesi

The castor plant (Ricinus communis L.) has been known since time immemorial in traditional medicine in the pharmacopeia of Mediterranean and eastern ancient cultures. Moreover, it is still used in folk medicine worldwide. Castor bean has been mainly recommended as anti-inflammatory, anthelmintic, anti-bacterial, laxative, abortifacient, for wounds, ulcers, and many other indications. Many cases of human intoxication occurred accidentally or voluntarily with the ingestion of castor seeds or derivatives. Ricinus toxicity depends on several molecules, among them the most important is ricin, a protein belonging to the family of ribosome-inactivating proteins. Ricin is the most studied of this category of proteins and it is also known to the general public, having been used for several biocrimes. This manuscript intends to give the reader an overview of ricin, focusing on the historical path to the current knowledge on this protein. The main steps of ricin research are here reported, with particular regard to its enzymatic activity, structure, and cytotoxicity. Moreover, we discuss ricin toxicity for animals and humans, as well as the relation between bioterrorism and ricin and its impact on environmental toxicity. Ricin has also been used to develop immunotoxins for the elimination of unwanted cells, mainly cancer cells; some of these immunoconjugates gave promising results in clinical trials but also showed critical limitation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sujatha Thankeswaran Parvathy ◽  
Amala Joseph Prabakaran ◽  
Thadakamalla Jayakrishna

AbstractCastor (Ricinus communis L) is an ideal model species for sex mechanism studies in monoecious angiosperms, due to wide variations in sex expression. Sex reversion to monoecy in pistillate lines, along with labile sex expression, negatively influences hybrid seed purity. The study focuses on understanding the mechanisms of unisexual flower development, sex reversions and sex variations in castor, using various genotypes with distinct sex expression pattern. Male and female flowers had 8 and 12 developmental stages respectively, were morphologically similar till stage 4, with an intermediate bisexual state and were intermediate between type 1 and type 2 flowers. Pistil abortion was earlier than stamen inhibition. Sex alterations occurred at floral and inflorescence level. While sex-reversion was unidirectional towards maleness via bisexual stage, at high day temperatures (Tmax > 38 °C), femaleness was restored with subsequent drop in temperatures. Temperature existing for 2–3 weeks during floral meristem development, influences sexuality of the flower. We report for first time that unisexuality is preceded by bisexuality in castor flowers which alters with genotype and temperature, and sex reversions as well as high sexual polymorphisms in castor are due to alterations in floral developmental pathways. Differentially expressed (male-abundant or male-specific) genes Short chain dehydrogenase reductase 2a (SDR) and WUSCHEL are possibly involved in sex determination of castor.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephanie E. Hereira-Pacheco ◽  
Yendi E. Navarro-Noya ◽  
Luc Dendooven

AbstractRhizosphere and root endophytic bacteria are crucial for plant development, but the question remains if their composition is similar and how environmental conditions, such as water content, affect their resemblance. Ricinus communis L., a highly drought resistant plant, was used to study how varying soil water content affected the bacterial community in uncultivated, non-rhizosphere and rhizosphere soil, and in its roots. Additionally, the bacterial community structure was determined in the seeds of R. communis at the onset of the experiment. Plants were cultivated in soil at three different watering regimes, i.e. 50% water holding capacity (WHC) or adjusted to 50% WHC every two weeks or every month. Reducing the soil water content strongly reduced plant and root dry biomass and plant development, but had little effect on the bacterial community structure. The bacterial community structure was affected significantly by cultivation of R. communis and showed large variations over time. After 6 months, the root endophytic bacterial community resembled that in the seeds more than in the rhizosphere. It was found that water content had only a limited effect on the bacterial community structure and the different bacterial groups, but R. communis affected the bacterial community profoundly.


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