Flour functional properties of purple maize (Zea mays L.) from Argentina. Influence of environmental growing conditions.

The objective was to characterize thermal and viscosity properties of flour of purple maize from Argentina, and to evaluate the environmental effects on composition and flour properties. Half-sib families were selected from original germplasm and reproduced during 2014 and 2015. Chemical composition, thermal and pasting properties of whole grain flour were determined. Non-purple genotypes were used as controls. Composition of purple maize did not show significant differences with controls, but amylose content was significantly lower. High variability in pasting and thermal properties of flour was observed between genotypes. Anthocyanin content positively correlated with breakdown (r = 0.37, P < 0.05), indicating that anthocyanins increased starch granules fragility during cooking. The higher gelatinization enthalpy of purple genotypes was coincident with the lower amylose content in relation to non-purple. The amylopectin retrogradation enthalpy negatively correlated with polyphenols (r = -0.35, P < 0.05) and anthocyanins (r = -0.40, P < 0.05), probably due to interactions formed after starch gelatinization. Flour functionality parameters showed higher effect of genotype and lower effects of environment and genotype × environment interaction. The variability found among genotypes indicates different flour behavior that would facilitate the identification of progenies with particular properties for production of functional maize based-foods.

Dietary starch types affect liver nutrient metabolism of finishing pigs.

This study aimed to evaluate the effect of different starch types on liver nutrient metabolism of finishing pigs. In all ninety barrows were randomly allocated to three diets with five replicates of six pigs, containing purified waxy maize starch (WMS), non-waxy maize starch (NMS) and pea starch (PS) (the amylose to amylopectin ratios were 0·07, 0·19 and 0·28, respectively). After 28 d of treatments, two per pen (close to the average body weight of the pen) were weighed individually, slaughtered and liver samples were collected. Compared with the WMS diet, the PS diet decreased the activities of glycogen phosphorylase, phosphoenolpyruvate carboxykinase and the expression of phosphoenolpyruvate carboxykinase 1 in liver (P0·05). Compared with the WMS diet, the PS diet reduced the expressions of glutamate dehydrogenase and carbamoyl phosphate synthetase 1 in liver (P<0·05). PS diet decreased the expression of the insulin receptor, and increased the expressions of mammalian target of rapamycin complex 1 and ribosomal protein S6 kinase ß-1 in liver compared with the WMS diet (P<0·05). These findings indicated that the diet with higher amylose content could down-regulate gluconeogenesis, and cause less fat deposition and more protein deposition by affecting the insulin/PI3K/protein kinase B signalling pathway in liver of finishing pigs.

Macromolecular Traits in the African Rice Oryza glaberrima and in Glaberrima/Sativa Crosses, and Their Relevance to Processing.

Molecular properties of proteins and starch were investigated in 2 accessions of Oryza glaberrima and Oryza sativa, and in one NERICA cross between the 2 species, to assess traits that could be relevant to transformation into specific foods. Protein nature and organization in O. glaberrima were different from those in O. sativa and in NERICA. Despite the similar cysteine content in all samples, thiol accessibility in O. glaberrima proteins was higher than in NERICA or in O. sativa. Inter-protein disulphide bonds were important for the formation of protein aggregates in O. glaberrima, whereas non-covalent protein-protein interactions were relevant in NERICA and O. sativa. DSC and NMR studies indicated only minor differences in the structure of starch in these species, as also made evident by their microstructural features. Nevertheless, starch gelatinization in O. glaberrima was very different from what was observed in O. sativa and NERICA. The content of soluble species in gelatinized starch from the various species in the presence/absence of treatments with specific enzymes indicated that release of small starch breakdown products was lowest in O. glaberrima, in particular from the amylopectin component. These findings may explain the low glycemic index of O. glaberrima, and provide a rationale for extending the use of O. glaberrima in the production of specific rice-based products, thus improving the economic value and the market appeal of African crops. PRACTICAL APPLICATION: The structural features of proteins and starch in O. glaberrima are very different from those in O. sativa and in the NERICA cross. These results appear useful as for extending the use of O. glaberrima cultivars in the design and production of specific rice-based products (for example, pasta), that might, in turn, improve the economic value and the market appeal of locally sourced raw materials, by introducing added-value products on the African market.

Transcriptomic identification and expression of starch and sucrose metabolism genes in the seeds of Chinese chestnut (Castanea mollissima).

The Chinese chestnut (Castanea mollissima) seed provides a rich source of carbohydrates as food and feed. However, little is known about starch biosynthesis in the seeds. The objectives of this study were to determine seed composition profiles and identify genes involved in starch and sucrose metabolism. Metabolite analysis showed that starch was the major component and rapidly accumulated during seed endosperm development. Amylopectin was approximately 3-fold of amylose content in chestnut starch. Illumina platform-based transcriptome sequencing generated 56671 unigenes in two cDNA libraries from seed endosperms collected at 45 and 75 days after flowering (DAF). A total of 1537 unigenes showed expression differences ≥2-fold in the two stages of seeds including 570 up-regulated and 967 down-regulated unigenes. One hundred and fifty-two unigenes were identified as involved in starch and sucrose metabolism, including 1 for glycogenin glucosyltransferase, 4 for adenylate transporter (brittle1-type), 3 for ADP-glucose pyrophosphorylase (AGP, not brittle2- or shrunken2-type), 3 for starch synthase (SS), 2 for starch branching enzyme, 5 for starch debranching enzyme, 11 for sucrose synthase, and 3 for sucrose-phosphate synthase. Among them, 58 unigenes showed a ≥2-fold expression difference between the 45 and 75 DAF seeds including 11 up- and 47 down-regulated unigenes. The expression of 21 unigenes putatively coding for major enzymes in starch and sucrose metabolism was validated by qPCR using RNA from five seed stages. Expression profiles and correlation analysis indicated that the mRNA levels of AGP (large and small subunits), granule-bound SS2, and soluble SS1 and SS4 were well-correlated with starch accumulation in the seeds. This study suggests that the starch biosynthesis pathway in Chinese chestnut is similar to that of potato tuber/Arabidopsis leaf and differs from that of maize endosperm. The information provides valuable metabolite and genetic resources for future research in starch and sucrose metabolism in Chinese chestnut tree.

Amylopectin biogenesis and characterization in the protozoan parasite Toxoplasma gondii, the intracellular development of which is restricted in the HepG2 cell line.

The obligate intracellular protozoan Toxoplasma gondii belongs to the phylum Apicomplexa, which is composed of numerous parasites causing major diseases such as malaria, toxoplasmosis and coccidiosis. The life cycle of T. gondii involves developmental processes from one stage to another with both asexual and sexual parasitic forms. Throughout their life cycle, some apicomplexan parasites accumulate a crystalline storage polysaccharide analogous to amylopectin within the cytoplasm. In T. gondii, both the slowly dividing encysted bradyzoites and the sporozoites of the sexual stage contain a high number of amylopectin granules (AG), while the rapidly replicating tachyzoites are devoid of amylopectin. It is thought that this storage polysaccharide may represent an energy reserve that could fuel the transition from one developmental stage to another one. At present, by comparison to glycogen and plant starch, little is known about the biosynthesis, structure and biological functions of amylopectin in T. gondii. Here, we describe an in vitro system allowing the production and purification of a large amount of amylopectin, which has been subjected to detailed biochemical and structural analyses. Our data indicate that T. gondii synthesizes a genuine amylopectin following changes in the environmental conditions and that this storage polysaccharide differs from glycogen and starch in terms of glucan chain length.

Ultrastructural differentiation of Toxoplasma gondii schizonts (types B to E) and gamonts in the intestines of cats fed bradyzoites.

The ultrastructural characterisitics of four types of Toxoplasma gondii schizonts (types B, C, D and E) and their merozoites, microgamonts and macrogamonts were compared in cats killed at days 1, 2, 4 and 6 after feeding tissues cysts from the brains of mice. Schizonts, merozoites and gamonts contained most of the ultrastructural features characteristic of the phylum Apicomplexa. All four types of schizonts developed within enterocytes or intraepithelial lymphocytes. Occasionally, type B and C schizonts developed within enterocytes that were displaced beneath the epithelium into the lamina propria. Type D and E schizonts and gamonts developed exclusively in the epithelium. Tachyzoites occurred exclusively within the lamina propria. Type B schizonts formed merozoites by endodyogeny, whereas types C to E developed by endopolygeny. The parasitophorous vacuoles surrounding type B and C schizonts consisted of a single membrane, whereas those surrounding types D and E schizonts were comprised of two to four electron-dense membranes. The parasitophorous vacuole of type B schizonts had an extensive tubulovesicular membrane network (TMN); the TMN was reduced or absent in type C schizonts and completely absent in types D and E schizonts and gamonts. Type B merozoites were ultrastructurally similar to tachyzoites, except that they were slightly larger. Type C merozoites exhibited a positive periodic acid-Schiff reaction by light microscopy and ultrastructurally contained amylopectin granules. Rhoptries were labyrinthine in type B merozoites but were electron-dense in types C-E. The development of microgamonts, macrogamont and oocysts is also described.

Contribuição à adaptação de uma técnica, para uso em campo, de determinação da amilose em raízes de mandioca - Parte I / Contribution to an adaptation of a technique of amilose determination in cassava roots to be used in the field work - Part I

Este estudo teve como objetivo padronizar e adaptar um método de determinação da amilose baseado no princípio da colorimetria, em bancada laboratorial, e, posteriormente, elaborar escalas de cores que possibilitassem as determinações qualitativa/semiquantitativa no campo, para seleção, após a colheita, de raízes de mandioca por teores de amilose/amilopectina. Os experimentos foram conduzidos no Laboratório de Ciência e Tecnologia de Alimentos da EMBRAPA Mandioca e Fruticultura, utilizando como referencial o método preconizado pela INTERNATIONAL ORGANIZATION FOR STANDARDIZATION. Foi elaborada uma curva padrão de amilose/amilopectina com dezenove pontos e uma posterior Escala de Cor correspondente, baseada nos valores da escala Pantone®. Duas outras escalas de cores foram elaboradas a partir da Escala de Cor da curva padrão, sendo uma por faixa de teores baixos, médios e altos e uma outra pelos valores médios dessas faixas de concentração de amilose. As análises espectrofotométrica e sensorial foram realizadas em seis variedades de mandioca do Banco Ativo de Germoplasma da EMBRAPA Mandioca e Fruticultura.

Liver transplantation for type I and type IV glycogen storage disease.

Progressive liver failure or hepatic complications of the primary disease led to orthotopic liver transplantation in eight children with glycogen storage disease over a 9-year period. One patient had glycogen storage disease (GSD) type I (von Gierke disease) and seven patients had type IV GSD (Andersen disease). As previously reported [19], a 16.5-year-old-girl with GSD type I was successfully treated in 1982 by orthotopic liver transplantation under cyclosporine and steroid immunosuppression. The metabolic consequences of the disease have been eliminated, the renal function and size have remained normal, and the patient has lived a normal young adult life. A late portal venous thrombosis was treated successfully with a distal splenorenal shunt. Orthotopic liver transplantation was performed in seven children with type N GSD who had progressive hepatic failure. Two patients died early from technical complications. The other five have no evidence of recurrent hepatic amylopectinosis after 1.1-5.8 postoperative years. They have had good physical and intellectual maturation. Amylopectin was found in many extrahepatic tissues prior to surgery, but cardiopathy and skeletal myopathy have not developed after transplantation. Postoperative heart biopsies from patients showed either minimal amylopectin deposits as long as 4.5 years following transplantation or a dramatic reduction in sequential biopsies from one patient who initially had dense myocardial deposits. Serious hepatic derangement is seen most commonly in types I and IV GSD. Liver transplantation cures the hepatic manifestations of both types. The extrahepatic deposition of abnormal glycogen appears not to be problematic in type I disease, and while potentially more threatening in type IV disease, may actually exhibit signs of regression after hepatic allografting.

Progressive cardiac failure following orthotopic liver transplantation for type IV glycogenosis.

Orthotopic liver transplantation (OLT) has been proposed to treat patients with type IV glycogenosis because of early progressive cirrhosis. Reports have shown absence of disease progression in other organs after OLT and even regression of cardiac amylopectin infiltration in one case. We describe a 15-month-old child in whom a liver transplant was performed for type IV glycogenosis. There were no clinical signs of extrahepatic disease before OLT. Nine months later, the patient developed progressive cardiac insufficiency and died from cardiac failure. Because of massive amylopectin deposits, decreased myofibrils in cardiac cells, and exclusion of other causes of cardiac failure, death was attributed to amylopectionosis. Our observation contrasts with the Pittsburgh experience and suggests that cardiac amylopectionosis may progress after OLT.

Rapid analysis of starch, amylose and amylopectin by high-performance size-exclusion chromatography.

Starch components, amylose and amylopectin, were analyzed by high-performance size-exclusion chromatography. These two-components were separated using a two-column system (E-Linear and E-1000) and dimethyl sulphoxide as the mobile phase. The void volume (V0 = 2.22 ml) was measured using tobacco mosaic virus. Column calibration was accomplished with dextrans of known average molecular weight (Mw range = 10,100-2,000,000). The elution volume of amylopectin (Ve = 2.5 ml) indicated that this starch component was fractionated on the column system despite its very large molecular size. Standard curves were prepared from various mixtures of purified corn and wheat amylose and amylopectin. From the linear relationships obtained, the percentages of both components in corn and wheat starches were determined. The method developed proved useful to monitor the purity of amylose and amylopectin preparations, and to estimate rapidly the amylose:amylopectin ratio of starch samples.