Thionins

The general designation of thionins has been proposed for a family of homologous peptides that includes purothionins, which were first isolated from wheat seeds (Balls el #/., 1942) and their homologues from various taxa that have been named viscotoxins and crambins (see Garcia-Olmedo el al., 1989). The crystalline protein material obtained from lipid extracts of wheat endosperm was designated "purothionins" because of its high sulphur content (Balls el al., 1942). This material was found to have bactericidal and fungicidal properties (Stuart and Harris, 1942), to inhibit fermentation of wheat mashes (Balls and Harris, 1944), and to be toxic to laboratory animals (Coulson el al„ 1942). The toxic properties of mistletoes were ascribed to the viscumin lectin and to a mixture of small basic proteins, designated - "viscotoxins" (Samuelsson, 1974). In a study of the seeds of the Abyssinian cabbage {Crambe abyssinica)^ a high-sulphur crystalline protein was obtained from the aqueous acetone extracts and designated "crambin" (Van Ettcn e/<?/., 1965)

Biochemical evidence of chromosome homoeology among related plant genera.

Biochemical markers associated with homoelogous chromosome groups 3 and 7 of Triticum aestivum L. have been investigated in genetic stocks carrying chromosomes or chromosomal segments of the same homoeology groups from Agropyron elongatum and Secale cereale. Chromosomes 3Ag of Agropyron and 3R of Secale control proteins a3 and b3 with the same properties as proteins 5, 6 and 7 associated with 3B and 3D of Triticum. It is concluded that genes for proteins 5, a3 and b3 are located in segments proximal to the centromere in the β arms of chromosomes 3D and 3Ag, respectively. Proteins 3, 4 and 11, controlled by 7D-short arm of Triticum, are replaced by proteins a7, b7 and c7, when that chromosome is replaced by 7 Ag. Genes for these proteins are located proximal to the centromere in the short arms of chromosomes 7D and 7 Ag. Finally, a gene that controls sterol esterification is similarly located in the short arms of chromosomes 7D and 7 A

Chromosomal location of a gene that controls sterol esterification in Triticum aestivum L.

A previously described D genome locus (Pln) that controls sterol esterification in the wheat kernel has been assigned to the short arm of chromosome 7 D by comparison of the steryl ester phenotype of euploid kernels of Triticum aestivum variety Chinese Spring with those of the compensated nulli-tetrasomic lines and the 7 D S ditelosomic. Palmitate is the predominant ester in all but the 7 D nullisomic combinations, which have linoleate as the main ester. These lines also show a marked decrease in sterol esterification and a two-fold increase in free sterol, indicating that chromosomes 7 A and 7 B do not compensate for the loss of esterification capacity associated with 7 D

Homeologous proteins synthesis controlled by homeologous chromosomes in wheat

Two homeologous proteins have been isolated from the endosperm of common wheat (genomes ABD). Synthesis of these two proteins is controlled by the homeologous chromosomes 7B and 7D respectively. However, Aegilops speltoides, the more generally accepted B genome donor, does not synthesize the 7B protein

Biochemical evidence of gene transfer from the Mv genome of Aegilops ventricosa to hexaploid wheat

Endosperm protein and isozyme patterns of Unes derived from the ovoss [Tritioum turgidum (AABB) x Aegilops ventrioosa (DDMVMV)] x T_. aes tivum (AABBDD) were studied. Five bioohemioal oharaoters pvesent in Ae_. ventrioosa (DDM°M°), Ae_. oomosa (MU) and Ae_. uniaris tata (MUMU) , but absent from Ae. squarrosa (DD)t T_. aes tivum (AABBDD) and T_. turgidum (AABB) were investigated. Three of these were identified in several Unes3 indioating gene transfer from the M° genome of Ae. ventrioosa into hexaploid wheat. The wide distribution of one of the markers (CM-4) suggests its previous transfer to the D genome of Ae. ventrioosa

Proportion of common wheat kernels in commercial samples of durum wheat by chemical methods

Durum wheat (Triticum durum Desf.) is used for production of semolina which is the required raw material for the elaboration of good quality pasta products. Common wheat (T. aestivum L,)t generally used in breadmaking, yields milling products (flour or fariña) that are not suitable for that purpose. Shortage and localization of durum wheat production, as well as its higher cost, have compelled the utilization of common wheat for the production of macaroni. When different blends of hérd or soft wheat (fariña or flour) with durum wheat are used, the quality of macaroni is reduced. Por this reason, the estimation of common wheat in pasta products is an important problem from the point of view of quality and market control, Chemical methods for detection and estimation of common wheat in pasta products have been developed in this laboratory during the past six years. The related problem of estimating the proportion of common wheat kernels in commercial samples of durum wheat has been traditionally solved either by niorphológica1 examination or by cytogenetical methods. The former are too unreliable and the latter too cumbersome, In this paper, we have reviewed the above mentioned chemical methods and investigated their application to the analysis of single kernels and the estimation of the proportion of common wheat kernels in commercial samples of durum wheat in order to avoid the cytogenetical methods or to confirm the morphological examination

Endosperm sterol phenotype and germination in wheat

Free and conjugated sterols of endosperm, coats, scutellum, coleoptile and roots have been analysed at different germination stages in two wheat cultivars with different endosperm sterol phenotypes. It seems that sterol metabolism of the developing tissues, namely coleoptile and roots, is not affected by the sterol conjugation profile of the endosperm. Enough sterol is present in the mature embryo to supply the germinating axis during the observation period (144 hr at 16°). The data suggest that sterol is transferred from scutellum to coleoptile and roots during germinatio

Una intensificación sostenible

La ausencia de los términos sostenible/sostenibilidad en el Diccionario de la Real Academia Española era insostenible, dado el protagonismo que habían alcanzado en el discurso cotidiano, siendo raro el día que no formaran parte de títulos de nuevos libros e informes o de titulares de periódicos. Cuando por fin se decidió incluirlos en sus páginas, se ha hecho de un modo tan contundente que es incompatible con el uso que venía haciéndose de ellos: «sostenible. dicho de un proceso que puede mantenerse por sí mismo, por ejemplo, un desarrollo económico sin ayuda exterior ni merma de los recursos existentes» y «sostenibilidad: cualidad de sostenible» Según esta definición, ningún proceso del mundo real, incluido el de producción de alimentos, sería sostenible. Por su esencia misma, una explotación agraria jamás cumpliría el citado criterio, ya que debe exportar cantidades considerables de un producto cuya generación requiere cantidades igualmente notables de insumos materiales, tales como agua, nutrientes, productos fitosanitarios y maquinaria, así como energía, ninguno de los cuales pueden generarse plenamente en la explotación, por lo que deben ser necesariamente importados a ésta. Sustainable, la palabra equivalente inglesa, se define de un modo más sensato y acorde con su uso universal, como dicha de un proceso que transcurre con el mínimo impacto posible sobre el medio ambiente. En general, todo proceso de desarrollo comporta una cierta degradación del medio, de modo que cuando se habla de desarrollo o de agricultura sostenibles sólo podemos aludir a procesos que se pretenden realizar con una degradación ambiental y un consumo de recursos que sean los mínimos posibles. Es esta definición más realista la que usaremos en esta conferencia. En suma, lo sostenible representa el mal menor, que es a lo más que podemos aspirar los humano

Genetics of synthesis of beta-sitosterol esters in wheat and related species

THE specificity of synthesis of -sitosterol esters in the endosperm of the allohexaploid wheat, Triticum aestivum (genomesABD), is different from that of the allotetraploid wheat, T. durum (genomes AB). Palmitate (P) followed by linoleate (L) are the main esters in the hexaploid, while linoleate accounts for more than 90 per cent of the sito-sterol esters in the tetraploid. Although the phenotypic difference between the two species is the presence of palmitate in T. aestivum, a complete system for palmitate and linoleate (P–L) synthesis is added with the D genome to T. durum (AB), because both Aegilops squarrosa (D) and a synthetic T. spelta (ABD) show the P–L pattern (Fig. 1

El caso de las colmenas vacías y otras historias

Me dijiste que dos de las cinco colmenas de tu padre habían aparecido vacías por sorpresa, y había querido la casualidad que esa misma mañana yo hubiera leído que David Hackenberg, un apicultor del Estado de Florida, acababa de dar cuenta de un masivo colapso de las colonias de abejas de su empresa: en una inspección de cuatrocientas colmenas que estaban sanas por completo tres semanas antes, 368 aparecían prácticamente vacías, ya que sólo conservaban la reina y un cierto número de crías, sin que quedara rastro siquiera de las obreras o de sus cadáveres. Parece que este tipo de incidente está repitiéndose con demasiada frecuencia en distintas partes del mundo y que la actividad apícola se enfrenta a un nuevo síndrome al que ha dado en llamarse de «despoblamiento o desabejamiento» de la colmen