Why cellular stress suppresses adipogenesis in skeletal tissue,but is ineffective in adipose tissue: Control of mesenchymal cell differentiation via integrin binding sites in extracellular matrices

This Perspective addresses one of the major puzzles of adipogenesis in adipose tissue, namely its resistance to cellular stress. It introduces a concept of “density” of integrin binding sites in extracellular matrix, proposes a cellular signaling explanation for the observed effects of matrix elasticity and of cell shape on mesenchymal stem cell differentiation, and discusses how specialized integrin binding sites in collagen IV-containing matrices guard two pivotal physiological and evolutionary processes: stress-resistant adipogenesis in adipose tissues and preservation of pluripotency of mesenchymal stem-like cells in their storage niches. Finally, it proposes strategies to suppress adipogenesis in adipose tissues.     

Detection of Staphylococcal Enterotoxin A,B, and C in Milk By an Elisa Procedure

Enterotoxigenic reference strains of Staphylococcus aureus were cultivated in sterile whole and skim milk for 18 h at 37°G. Staphylococcal enterotoxin A, B, and C were detected directly in the milk by an enzyme linked immunosorbent assay (ELISA), sensitive down to 1 ng/ml. Enterotoxins in the range of 1 ng–20 µg/ml milk were detected without any concentration or extraction. Skim and whole milk were almost identical as medium for enterotoxin production.     

Chronopharmacokinetics and Cardiovascular Effects of Nifedipine

Orcadian phase dependency in pharmacokinetics and hemodynamic effects on blood pressure and heart rate of different galenic formulations of nifedipine (immediate-release, sustained-release, and i.v. solution) were studied in healthy subjects or in hypertensive patients. Pharmacokinetics of immediate-release but not sustained-release and i.v. nifedipine were dependent on time of day: immediate-release nifedipine had higher C_max (peak concentration) and shorter t_max (time-to-peak concentration) after morning than evening application, and bioavailibility in the evening was reduced by about 40%. Orcadian rhythm in estimated hepatic blood flow as determined by indocyanine green kinetics may contribute to these chronokinetics. A circadian time dependency was also found in nifedipine-induced effects on blood pressure and heart rate as monitored by 24-h ambulatory blood pressure measurements. In conclusion, the dose response relationship of oral nifedipine is influenced by the circadian organization of the cardiovascular system as well as by the galenic drug formulation.     

Multimodal nonlinear optical imaging of collagen arrays

We report multimodal nonlinear optical imaging of fascia, a rich collagen type I sheath around internal organs and muscle. We show that second harmonic generation (SHG), third harmonic generation (THG) and Coherent anti-Stokes Raman scattering (CARS) microscopy techniques provide complementary information about the sub-micron architecture of collagen arrays. Forward direction SHG microscopy reveals the fibrillar arrangement of collagen type I structures as the main matrix component of fascia. SHG images detected in the backward direction as well as images of forward direction CARS microscopy show that the longitudinal collagen fiber bundles are further arranged in sheet-like bands. Forward-THG microscopy reveals the optically homogeneous content of the collagen sheet on a spatial scale of the optical wavelength. This is supported by the fact that the third harmonic signal is observed only at the boundaries between the sheets as well as by the CARS data obtained in both directions. The observations made with THG and CARS microscopy are explained using atomic force microscopy images.     

Functional Anatomy of the Ovule in Broad Bean (Vicia faba L.): Ultrastructural Seed Development and Nutrient Pathways

Ovules of broad bean (Vicia faba L.) were studied to discloseultrastructural features, which can facilitate nutrient transportto the embryo sac from 10 d after pollination (DAP) to the matureseed. Fertilization occurs during the first 24 h after pollination.The endosperm is a coenocyte, which is eventually consumed bythe embryo. By 10 DAP the inner integument is degraded and theouter integument adjoins the embryo sac boundary. The heart-shapedembryo approaches the embryo sac boundary at two sites, whichhere are named contact zones. Small integument cells in theneighbourhood of the first formed contact zones become separatedby prominent intercellular spaces. A heterogenous scatteringmaterial, probably representing secretion products accumulatesin these spaces. By 14-16 DAP the integument exudate disappears,and the suspensor degenerates. As the contact zones increasein size, wall ingrowths form a bridging network in the narrowspace between the embryo sac boundary and the extra-embryonicpart of the endosperm wall. The epidermal cells of the embryoseparate adjacent to these zones, and develop conspicuous wallingrowths. At 20 DAP vacuoles showing various stages in formationof protein bodies appear in the cells of the embryo.Copyright1994, 1999 Academic Press Vicia faba, broad beans, ovule, seed, nutrient transport     

A conserved ClpP‐like protease involved in spore outgrowth in Bacillus subtilis

Germination and outgrowth of endospores of the Gram‐positive bacterium Bacillus subtilis involves the degradation and conversion to free amino acids of abundant proteins located in the spore core known as small acid‐soluble proteins (SASP). This degradation is mediated primarily by the germination protease Gpr. Here we show that YmfB, a distant homologue of ClpP serine proteases that is highly conserved among endospore‐forming bacteria, contributes to SASP degradation but that its function is normally masked by Gpr. Spores from a ymfB gpr double mutant were more delayed in spore outgrowth and more impaired in SASP degradation than were spores from a gpr single mutant. The activity of YmfB relied on three putative active‐site residues as well as on the product of a small gene ylzJ located immediately downstream of, and overlapping with, ymfB. We propose that YmfB is an orphan ClpP protease that is dedicated to the degradation of a specialized family of small protein substrates.     

Biomarkers in Exhaled Breath Condensate Are Not Predictive for Pulmonary Exacerbations in Children with Cystic Fibrosis: Results of a One-Year Observational Study

BackgroundCystic Fibrosis (CF) is characterized by chronically inflamed airways, and inflammation even increases during pulmonary exacerbations. These adverse events have an important influence on the well-being, quality of life, and lung function of patients with CF. Prediction of exacerbations by inflammatory markers in exhaled breath condensate (EBC) combined with early treatment may prevent these pulmonary exacerbations and may improve the prognosis.AimTo investigate the diagnostic accuracy of a set of inflammatory markers in EBC to predict pulmonary exacerbations in children with CF.MethodsIn this one-year prospective observational study, 49 children with CF were included. During study visits with an interval of 2 months, a symptom questionnaire was completed, EBC was collected, and lung function measurements were performed. The acidity of EBC was measured directly after collection. Inflammatory markers interleukin (IL)-6, IL-8, tumor necrosis factor α (TNF-α), and macrophage migration inhibitory factor (MIF) were measured using high sensitivity bead based flow immunoassays. Pulmonary exacerbations were recorded during the study and were defined in two ways. The predictive power of inflammatory markers and the other covariates was assessed using conditionally specified models and a receiver operating characteristic curve (SAS version 9.2). In addition, k-nearest neighbors (KNN) algorithm was applied (SAS version 9.2).ResultsSixty-five percent of the children had one or more exacerbations during the study. The conditionally specified models showed an overall correct prediction rate of 55%. The area under the curve (AUC) was equal to 0.62. The results obtained with the KNN algorithm were very similar.ConclusionAlthough there is some evidence indicating that the predictors outperform random guessing, the general diagnostic accuracy of EBC acidity and the EBC inflammatory markers IL-6, IL-8, TNF-α and MIF is low. At present it is not possible to predict pulmonary exacerbations in children with CF with the chosen biomarkers and the method of EBC analysis. The biochemical measurements of EBC markers should be improved and other techniques should be considered.     

Ultrastructural Differentiation of the Ovarian Transmitting Tissue in Lilium regale

The cells of the ovarian transmitting tissue of Lilium regaleare papilla shaped and form and epithelium on the placenta.Their ultrastructural organization and differentiation from1 d before to 7 d after anthesis is presented. These placentacells are typical transfer cells with a prominent secretionzone similar to that known from stylar canal cells. After anthesisthe secretion zone continues to grow by addition of vesiclefrom the numerous dictyosomes. Maximum depth of this zone isreached by day 4 after anthesis. The outer surface of the cellwall is distinctly rugged on cell maturation and the outermostlayer is corroded. The ER system undergoes transition from asmooth to a granular condition. Before anthesis there is a centralvacuole which at anthesis is reduced to a system of small vauoles.These are supplemented by autophagic vacuoles formed from theER. Such vacuoles are found near the secretion zone and mayalso fuse with the plasmalemma. The cuticle is sloughed andsecretion commences before anthesis. Accumulations of vesiclesfound in the nucleus and occasional connections between suchvesicles and the inner membrane of the nuclear envelope indicatethe presence of a nuclear network. Protein crystals are presentin the cytoplasm and the nucleus. The starch grains in the plastidsare digested after anthesis, but new ones are formed by days6 and 7.Copyright 1995, 1999 Academic Press Lilium regale, transmitting tissue, placenta, secretion, nuclear reticulum, transfer cells