Ultrastructure of Maize Starch Granules. A Review

History of starch granule ultrastructure and the principal data obtained on maize starch granules are analyzed. New results are developed: i) growth and development of the maize starch granules during maturation depend on the maize varieties and the tissue site in the kernel, especially the horny and flloury endosperms; ii) cytochemical studies of the starch granules differing from their amylose/amylopectin ratio show important differences in the distribution of their crystalline and amorphous zones that explain their behaviour under some hydrolytic treatments; iii) complexing between colloidal gold labelled concanavalin-A and starch (amylopectin) permits new and greater specificity to ultrastructural study of the starch granule

Extrusion-Cooking of Pea Flour: Structural and Immunocytochemical Aspects

Pea flour was submitted to extrusion-cooking under various conditions. The progressive structural transformation was investigated by light microscopy and immuno- gold transmission electron microscopy. Each of the three major compounds, i.e., starch granules, protein bodies, and cell wall fragments, develop a specific, independent structure. Protein bodies aggregate and fuse giving a protein matrix. Starch granules swell, deform, come into contact with each other, and ultimately also fuse together. The resulting gel expands giving a honeycombed structure. Consequently, the protein matrix is arranged into dense strata, i.e,. protein fibers in cross or longitudinal sections, disrupted by the expanded starch gel. Cell wall fragments are clustered together and seem to be intact. This structural segregation is shown to be related to the fact that protein bodies fuse before starch granules. The use of pressure and heating models in conjunction with scruming electron microscopy confirm this observation. On the other hand, immuno-gold labelling has shown that the legumin fraction was localized in the protein bodies as well as in the protein fibers. This indicates that, during extrusion-cooking, some of the antigenic determinants of this protein were not affected

Accumulation and Changes in Composition of Collagens in Subcutaneous Adipose Tissue After Bariatric Surgery

International audienceExtracellular matrix (ECM) in sc adipose tissue (scAT) undergoes pathological remodeling during obesity. However, its evolution during weight loss remains poorly explored.Objective:The objective of the investigation was to study the histological, transcriptomic, and physical characteristics of scAT ECM remodeling during the first year of bariatric surgery (BS)-induced weight loss and their relationships with metabolic and bioclinical improvements.Design, Setting, Patients, and Interventions:A total of 118 morbidly obese candidates for BS were recruited and followed up during 1 year after BS.Main Outcome Measures:scAT surgical biopsy and needle aspiration as well as scAT stiffness measurement were performed in three subgroups before and after BS. Fourteen nonobese, nondiabetic subjects served as controls.Results:Significantly increased picrosirius-red-stained collagen accumulation in scAT after BS was observed along with fat mass loss, despite metabolic and inflammatory improvements and undetectable changes of scAT stiffness. Collagen accumulation positively associated with M2-macrophages (CD163+ cells) before BS but negatively afterward. Expression levels of genes encoding ECM components (eg, COL3A1, COL6A1, COL6A2, ELN), cross-linking enzymes (eg, lysyl oxidase [LOX], LOXL4, transglutaminase), metalloproteinases, and their inhibitors were modified 1 year after BS. LOX expression and protein were significantly decreased and associated with decreased fat mass as well as other cross-linking enzymes. Although total collagen I and VI staining decreased 1 year after BS, we found increased degraded collagen I and III in scAT, suggesting increased degradation.Conclusions:After BS-induced weight loss and related metabolic improvements, scAT displays major collagen remodeling with an increased picrosirius-red staining that relates to increased collagen degradation and importantly decreased cross-linking. These features are in agreement with adequate ECM adaptation during fat mass loss- See more at: http://press.endocrine.org/doi/10.1210/jc.2015-3348#sthash.PLeUvzKd.dpu

Ultrastructure des grains d'amidon de mais. Revue

10 illus. 77 ref. SEM, Inc., AMF O'Hare (Chicago), USAInternational audienc

Ultrastructure des grains d'amidon de mais. Revue

10 illus. 77 ref. SEM, Inc., AMF O'Hare (Chicago), USAInternational audienc

Recent advances in microscopy of starch

National audienc

Microscopie electronique appliquee a l'agroalimentaire

2. ed. 59 ref. Mention d'édition : 2. ed.National audienc

Le monde invisible de ce que nous mangeons

National audienc

Characterisation and stability during storage of liposomes made of muscle phospholipids

International audienc

Microscopy of starch : evidence of a new level of granule organization

International audienc