Exemples de tératologie chez les Chitinozoaires du Pridoli de Libye et implications sur la signification biologique du groupe

Jaglin, J.-C. & Paris, F. 1992 04 IS: Exemples de tératologie chez les Chitinozoaires du Pridoli de Libye et implications sur la signification biologique du groupe. [Teratologic cases among Pridolian chitinozoans from Libya and implications on the biological interpretation of the group.] Lethaia , Vol. 25, pp. 151–164. Oslo. ISSN 0024–1164.
Fairly numerous chitinozoans displaying morphological anomalies are recorded in Late Silurian subsurface material from Western Libya. The individuals described and illustrated in our paper range exclusively in a short interval at the top of the investigated sequence. These abnormal vesicles are interpreted as teratologic cases related lo an event of unknown origin. From our conclusions, the hypothesis of vegetative reproduction stages stated by previous authors seems unlikely. Therefore we still interpret the chitinozoan vesicles as eggs (or to a lesser extent as spores) of marine organisms. * Libya, Chitinozoans, Silurian, teratology, chitinozoan affinities .     

Daily malate fluctuations in Sedum dasyphyllum L.

Abstract

Sedum dasyphyllum L. leaves of well-watered plants kept outdoors and under controlled conditions show diurnal malic acid fluctuations. In well-watered plants growing outdoors the malate accumulation undergoes seasonal variations and seems to be inhibited by short photoperiod and/or by low temperature. The seasonal variations of CAM activity correspond to seasonal variations of mesophyll succulence. Water stress markedly depressed CAM activity. In fact, plants of S. dasyphyllum show, under controlled conditions, a decrease of malate accumulation as relative water content decreases. Recovery from water stress is fairly slow. Water potential quickly increases during rewatering and exceeds the original value after few days, suggesting a consumption of osmotic compounds during the water stress period.     

Gas exchange of two CAM species of the genus Cissus (vitaceae) differing in morphological features

NADP-malate dehydrogenase extracted from darkened leaves of the C₃ plants pea, barley, wheat and spinach was activated by reduced glutathione, a monothiol, as well as by dithiothreitol (DTT). However, in the C₄ plants maize and Flaveria trinervia, only dithiothreitol could effectively activate the enzyme. There was no activation of the maize enzyme and little or no activation of the F. trinervia enzyme by glutathione. The failure of glutathione to activate NADP-MDH in leaf extracts of maize and F. trinervia may indicate there is some difference in disulfide groups of the protein compared to the C₃ plant enzyme. Both DTT and glutathione could activate NADP-malate dehydrogenase in a partially purified enzyme preparation from pea leaves with or without addition of partially purified thioredoxin. However, the required concentration of reductant was lower with addition of thioredoxin than in its absence. In extracts of C₃ species and the partially purified pea enzyme the level of activation after 40 to 60 min under aerobic conditions was higher (up to twofold) with DTT than with glutathione. Under anaerobic conditions, the initial rate of activation was about twice as high with DTT as with glutathione, but the total activation after 40 to 60 min was similar. Ascorbate was totally ineffective as a reducing agent in activating NADP-MDH from C₃ or C₄ plants, possibly due to its more positive redox potential.Abbreviations Chl Chlorophyll - DTT Dithiothreitol - GSH Reduced Glutathione - NADP-MDH NADP-malate Dehydrogenase     

Adipose-derived stem cells:Pathophysiologic implications vs therapeutic potential in systemic sclerosis

Adipose-derived stem cells(ADSCs)residing in the stromal vascular fraction(SVF)of white adipose tissue are recently emerging as an alternative tool for stem cell-based therapy in systemic sclerosis(SSc),a complex connective tissue disorder affecting the skin and internal organs with fibrotic and vascular lesions.Several preclinical and clinical studies have reported promising therapeutic effects of fat grafting and autologous SVF/ADSC-based local treatment for facial and hand cutaneous manifestations of SSc patients.However,currently available data indicate that ADSCs may represent a double-edged sword in SSc,as they may exhibit a pro-fibrotic and anti-adipogenic phenotype,possibly behaving as an additional pathogenic source of pro-fibrotic myofibroblasts through the adipocyte-to-myofibroblast transition process.Thus,in the perspective of a larger employ of SSc-ADSCs for further therapeutic applications,it is important to definitely unravel whether these cells present a comparable phenotype and similar immunosuppressive,anti-inflammatory,anti-fibrotic and pro-angiogenic properties in respect to healthy ADSCs.In light of the dual role that ADSCs seem to play in SSc,this review will provide a summary of the most recent insights into the preclinical and clinical studies employing SVF and ADSCs for the treatment of the disease and,at the same time,will focus on the main findings highlighting the possible involvement of these stem cells in SSc-related fibrosis pathogenesis.     

Influence of Tomato Plant Mycorrhization on Nitrogen Metabolism,Growth and Fructification on P-Limited Soil

Journal of Plant Growth Regulation - The application of mycorrhizal fungi in agricultural soils as bio-fertilizers is going to be established as an agronomic practice for enhancing crop nutrients...     

Brillouin microscopy for the evaluation of hair micromechanics and effect of bleaching

Brillouin microscopy is a new form of optical elastography and an emerging technique in mechanobiology and biomedical physics. It was applied here to map the viscoelastic properties of human hair and to determine the effect of bleaching on hair properties. For hair samples, longitudinal measurements (i.e. along the fibre axis) revealed peaks at 18.7 and 20.7 GHz at the location of the cuticle and cortex, respectively. For hair treated with a bleaching agent, the frequency shifts for the cuticle and cortex were 19.7 and 21.0 GHz, respectively, suggesting that bleaching increases the cuticle modulus and—to a minor extent—the cortex modulus. These results demonstrate the capability of Brillouin spectroscopy to address questions on micromechanical properties of hair and to validate the effect of applied treatments.