SHIP-1 inhibits CD95/APO-1/Fas-induced apoptosis in primary T lymphocytes and T leukemic cells by promoting CD95 glycosylation independently of its phosphatase activity

in Leukemia : Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K (2010)

SHIP-1 functions as a negative regulator of immune responses by hydrolyzing phosphatidylinositol-3,4,5-triphosphate generated by PI 3-kinase activity. As a result, SHIP-1 deficiency in mice results in ... [more ▼]

SHIP-1 functions as a negative regulator of immune responses by hydrolyzing phosphatidylinositol-3,4,5-triphosphate generated by PI 3-kinase activity. As a result, SHIP-1 deficiency in mice results in myeloproliferation and B cell lymphoma. On the other hand, SHIP-1 deficient mice have a reduced T cell population, but the underlying mechanisms are unknown. In this work, we hypothesized that SHIP-1 plays anti-apoptotic functions in T cells upon stimulation of the death receptor CD95/APO-1/Fas. Using primary T cells from SHIP-1-/- mice and T leukemic cell lines, we report here that SHIP-1 is a potent inhibitor of CD95-induced death. We observed that a small fraction of the SHIP-1 pool is localized to the endoplasmic reticulum where it promotes CD95 glycosylation. This post-translational modification requires an intact SH2 domain of SHIP-1, but is independent of its phosphatase activity. The glycosylated CD95 fails to oligomerize upon stimulation, resulting in impaired DISC formation and downstream apoptotic cascade. These results uncover an unanticipated inhibitory function for SHIP-1 and emphasize the role of glycosylation in the regulation of CD95 signaling in T cells. This work may also provide a new basis for therapeutic strategies using compounds inducing apoptosis through the CD95 pathway on SHIP-1 negative leukemic T cells. [less ▲]

SHIP2 et signalisation de l'insuline: quel role dans la pathogenese et le traitement du diabete de type 2?

in Bulletin et Mémoires de l'Académie Royale de Médecine de Belgique (2003), 158(7-9), 335-9

Based on the analysis of SHIP2+/- and SHIP2-/- mice showing that the lipid phophatase SHIP2 is an important negative regulator of the insulin pathway, we have suggested that the enzyme is a candidate gene ... [more ▼]

Based on the analysis of SHIP2+/- and SHIP2-/- mice showing that the lipid phophatase SHIP2 is an important negative regulator of the insulin pathway, we have suggested that the enzyme is a candidate gene for genetic predisposition to type 2 diabetes, and a potential therapeutic target for the same disease. Two years after, we propose to review these hypothesis in light of recent results from our laboratory, from international collaborations and from competitors in the field. [less ▲]

Shoah und Zionismus. Jüdische Geschichtserfahrung im Spiegel „deutsch-jüdischer“ Autobiographie

Conference given outside the academic context (2003)

Shoals and schools: back to the heuristic definitions and quantitative references

in Reviews in Fish Biology & Fisheries (2012), 22

The terms 'shoal', 'swarm' and 'school' are very frequently used in research on collective behaviours in animals. Pitcher's definitions are accepted as the authority in the field but are based on a ... [more ▼]

The terms 'shoal', 'swarm' and 'school' are very frequently used in research on collective behaviours in animals. Pitcher's definitions are accepted as the authority in the field but are based on a conceptual criterion of sociability. Without call into question the basis of these definitions, they do not provide tools to determine these behaviours quantitatively. To compare studies between populations, species, taxa or different experimental treatments, and between different authors, quantitative references are necessary. Quantitative measurements of collective behaviours can also test and validate the predictive capacity of computer models by comparing real data from nature so that different models can be compared. The first part of this paper succinctly reviews the definitions and meanings of these behaviours, with particular attention paid to quantitative aspects. This review underlines a series of conceptual confusions concerning these behavioural terms observed in the scientific literature and oral scientific communications. The second part reviews the quantitative parameters developed by biologists studying collective fish behaviours, mainly fish shoals, and by theoretical biologists and physicists studying computer modelling of collective behaviours. The parameters reviewed herein make no attempt to explain the mechanisms and causes that create a shoal, a swarm or a school, but rather try to describe these collective behaviours, and to connect local and global properties with individual and collective behaviours. Recent development over the last decade in technology, data processing capacity, cameras, and video tracking tools have provided the opportunity to obtain quantitative measures of collective dynamic behaviours in animals both rapidly and precisely. [less ▲]

Shock-capturing Methods for Mixed Flows Simulations: A Comparative Study

in Computers & Fluids (n.d.), Submitted

The shoot apical meristem of Sinapis alba L. expands its central symplasmic field during the floral transition

in Planta (2002), 215(1), 67-78

The shoot apical meristem (SAM) is functionally subdivided into zones with distinct tasks. During vegetative growth the peripheral zone of the meristem gives rise to leaf primordia that develop into ... [more ▼]

The shoot apical meristem (SAM) is functionally subdivided into zones with distinct tasks. During vegetative growth the peripheral zone of the meristem gives rise to leaf primordia that develop into dorsiventral leaves under the influence of signals from the central zone. During the floral transition the function of the SAM is altered and its peripheral zone starts to form floral structures in a specific pattern. This requires alterations in the signal networks that coordinate the activities of the peripheral and central zone of the SAM. These signal networks are partly housed in the symplasmic space of the SAM. Dye-coupling experiments demonstrate that in the superficial layer of the Sinapis alba meristem this space is radially subdivided. The cells of the central zone are coupled into a symplasmic field, which is shielded from the peripheral zone by the positional closing of plasmodesmata. In the vegetative meristems, most of these central symplasmic fields have a triangular geometry and are relatively small in size. Plants that are induced to flower by exposure to a single long day alter the geometry as well as the size of their central symplasmic field. After two subsequent days under short photoperiod the central symplasmic fields exhibit a circular form. Simultaneously. their size strongly increases both in an absolute sense and relative to the enlarging meristem. The geometric change in the fields is hypothesized to be due to recruitment of extra initial cells, required to support the increase in phyllotactic complexity. The proportional increase in field size is interpreted as an adjustment in the balance between the central and peripheral zone of the SAM, accompanying the shift from leaf production to flower formation. [less ▲]

Short administration of metformin improves insulin sensitivity in android obese subjects with impaired glucose tolerance.

in Diabetic Medicine : A Journal of the British Diabetic Association (1995), 12(11), 985-9

In a double-blind, randomized, cross-over study, the metabolic effects of a short treatment with metformin (2 x 850 mg day-1 for 2 days and 850 mg 1 h before evaluation) were compared to those of placebo ... [more ▼]

In a double-blind, randomized, cross-over study, the metabolic effects of a short treatment with metformin (2 x 850 mg day-1 for 2 days and 850 mg 1 h before evaluation) were compared to those of placebo in 15 obese subjects (BMI: 33.2 +/- 0.9 kg m-2), with abdominal distribution of adipose tissue and impaired glucose tolerance. An intravenous glucose tolerance test (0.3 g glucose kg-1) was performed after each period of treatment. Areas under the curve (AUC0-180 min) were calculated for plasma glucose, insulin, and C-peptide levels. Glucose tolerance was estimated by the coefficient of glucose assimilation (KG). Insulin sensitivity (SI) and glucose effectiveness (SG) indices were calculated using Bergman's minimal model. Insulin secretion rate (ISR) was determined by deconvolution of plasma C-peptide levels and insulin metabolic clearance rate (MCR) was estimated by dividing AUC 1SR by AUC insulin. Fasting plasma insulin levels were reduced after metformin (89.3 +/- 15.9 vs 112.4 +/- 24.3 pmol l-1; p = 0.04). AUC glucose, KG and SG were similar in both tests. However, AUC insulin was reduced (39.7 +/- 6.5 vs 51.8 +/- 10.4 nmol min l-1; p = 0.02), while SI (6.98 +/- 1.14 vs 4.61 +/- 0.42 10(-5) min-1 pmol-1 l; p = 0.03) and insulin MCR (715 +/- 116 vs 617 +/- 94 ml min-1 m-2; p = 0.03) were increased after metformin. The demonstration that metformin rapidly improves insulin sensitivity should encourage further research to evaluate the long-term effects of metformin in android obese subjects with impaired oral glucose tolerance. [less ▲]

Short and long-term prognosis of small acute myocardial infarction : a natural history study

in European Heart Journal Supplements : Journal of the European Society of Cardiology (1987), 8(suppl.2), 110

A short C-rich PNA fragment capable to form novel G-quadruplex-PNA complexes

in Nucleic Acids Symposium Series (2008), 52

In this work we investigated the interaction between the short ac(4)a C-rich peptide nucleic acid (PNA) probe and two intramolecular G-quadruplex targets having the same G-tetrad core, but different ... [more ▼]

In this work we investigated the interaction between the short ac(4)a C-rich peptide nucleic acid (PNA) probe and two intramolecular G-quadruplex targets having the same G-tetrad core, but different folding topologies. The T(G(4)T)(3)G(4)T and the recently reported tetra-end-linked-(TG(4)T)(4) G-rich oligonucleotides (GROs) were chosen and synthesized for this study. UV, CD, and MS experiments revealed the formation of novel 1:1 G-quadruplex-PNA complexes besides the expected DNA-PNA heteroduplexes [less ▲]

Short communication: correlations of marker-assisted breeding values with progeny-test breeding values for eight hundred ninety-nine French Holstein bulls.

in Journal of Dairy Science (2008), 91(6), 2520-2

French artificial insemination companies have been running a marker-assisted selection program since 2001 to determine which young bulls should be progeny tested. A first batch of 899 Holstein sires ... [more ▼]

French artificial insemination companies have been running a marker-assisted selection program since 2001 to determine which young bulls should be progeny tested. A first batch of 899 Holstein sires receiving their first proofs based on progeny daughters has been studied. Estimated breeding values with or without marker information were computed based on information available in April 2004, and correlated to daughter yield deviations available in 2007 for production traits. Marker-assisted estimated breeding values presented greater correlations with daughter yield deviations than those calculated using only pedigree index. The average improvement in correlation was 0.043 and ranged from +0.001 for protein yield to +0.103 for fat percentage. This gain was based on the initial and suboptimal conditions of the program and is expected to increase in the coming years because of several improvements implemented since the start of the marker-assisted selection program. [less ▲]