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Acta Crystallographica Section F: Structural Biology and Crystallization Communications (1)
Immunity & Ageing : I & A (1)
Coombs, Graham H. (1)
Crombet Ramos, Tania (1)
Fyfe, Paul K. (1)
García Verdecia, Beatriz (1)
Hunter, William N. (1)
Lage Dávila, Agustín (1)
Leonard Rupalé, Idrissa (1)
Lorenzo-Luaces, Patricia (1)
Mazorra Herrera, Zaima (1)
Müller, Sylke (1)
Ramos, Tania (1)
Saavedra Hernández, Danay (1)
Westrop, Gareth D. (1)
de Jesús Badía Alvarez, Teresita (1)
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Immunosenescence and gender: a study in healthy Cubans
García Verdecia, Beatriz
Saavedra Hernández, Danay
de Jesús Badía Alvarez, Teresita
Leonard Rupalé, Idrissa
Mazorra Herrera, Zaima
Lage Dávila, Agustín
Immunity & Ageing : I & A
The progressive decline in the immune function during ageing is termed immunosenescence. Previous studies have reported differences between males and females in the distribution and cell responses of lymphocyte subsets. Most studies of immunosenescence have been done in populations of industrialized countries living in a rather cold environment, and facing lower antigenic challenges such as Cytomegalovirus (CMV). The aim of this study was to determine the effect of ageing on lymphocytes in a population with a high prevalence of CMV infection in all ages, and to compare gender differences related to the immunosenescence markers.
Different populations of peripheral blood leukocytes from healthy young and old IgG-CMV seropositive individuals were examined using flow cytometry. With age, the number and frequency of B cells and T cells significantly decreased, while highly differentiated T cells increased. Such changes were different in males and females. The age-associated decline of less differentiated lymphocyte subsets (CD19, CD4 and CD8 cells) and the increase of highly differentiated T cells were more prominent in females. In males, there were no significant changes in CD19, CD4 and CD8 subsets but there was a significant increase in the proportion of highly differentiated T cells.
Shifts in lymphocyte subsets distribution were influenced by age and gender in an IgG-CMV seropositive population. These results suggest different patterns of immunosenescence in respect to gender differences. These patterns could have implications in the design of immunotherapy in the elderly.
Structure of Leishmania major cysteine synthase
Fyfe, Paul K.
Westrop, Gareth D.
Coombs, Graham H.
Hunter, William N.
Acta Crystallographica Section F: Structural Biology and Crystallization Communications
A crystallographic and biochemical study of L. major cysteine synthase, which is a pyridoxyl phosphate-dependent enzyme, is reported. The structure was determined to 1.8 Å resolution and revealed that the cofactor has been lost and that a fragment of γ-poly-d-glutamic acid, a crystallization ingredient, was bound in the active site. The enzyme was inhibited by peptides.
Cysteine biosynthesis is a potential target for drug development against parasitic Leishmania species; these protozoa are responsible for a range of serious diseases. To improve understanding of this aspect of Leishmania biology, a crystallographic and biochemical study of L. major cysteine synthase has been undertaken, seeking to understand its structure, enzyme activity and modes of inhibition. Active enzyme was purified, assayed and crystallized in an orthorhombic form with a dimer in the asymmetric unit. Diffraction data extending to 1.8 Å resolution were measured and the structure was solved by molecular replacement. A fragment of γ-poly-d-glutamic acid, a constituent of the crystallization mixture, was bound in the enzyme active site. Although a d-glutamate tetrapeptide had insignificant inhibitory activity, the enzyme was competitively inhibited (K i = 4 µM) by DYVI, a peptide based on the C-terminus of the partner serine acetyltransferase with which the enzyme forms a complex. The structure surprisingly revealed that the cofactor pyridoxal phosphate had been lost during crystallization.
Arabidopsis thaliana; cysteine synthase; Leishmania major
Results 1-2 (2)
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