Loss of Vimentin Enhances Cell Motility through Small Confining Spaces

The migration of cells through constricting spaces or along fibrous tracks in tissues is important for many biological processes and depends on the mechanical properties of a cytoskeleton made up of three different filaments: F‐actin, microtubules, and intermediate filaments. The signaling pathways and cytoskeletal structures that control cell motility on 2D are often very different from those that control motility in 3D. Previous studies have shown that intermediate filaments can promote actin‐driven protrusions at the cell edge, but have little effect on overall motility of cells on flat surfaces. They are however important for cells to maintain resistance to repeated compressive stresses that are expected to occur in vivo. Using mouse embryonic fibroblasts derived from wild‐type and vimentin‐null mice, it is found that loss of vimentin increases motility in 3D microchannels even though on flat surfaces it has the opposite effect. Atomic force microscopy and traction force microscopy experiments reveal that vimentin enhances perinuclear cell stiffness while maintaining the same level of acto‐myosin contractility in cells. A minimal model in which a perinuclear vimentin cage constricts along with the nucleus during motility through confining spaces, providing mechanical resistance against large strains that could damage the structural integrity of cells, is proposed.     

One-Step Synthesis of Thermoplastic Phenylsilsesquioxane Polymer and Its Copolymers with Diphenylsiloxanes

The preparation of reversibly softening polymers and copolymers of phenylsilsesquioxane in a one-step synthesis has been studied. The synthetic methods are based on hydrolytic polycondensation of PhSiCl₃ or copolycondensation of PhSiCl₃ with Ph₂SiCl₂ using moistened or hydrated salts: (1) moistened Na₂CO₃, K₂CO₃, (2) Na₂B₄O₇·10H₂O, (3) Na₃PO₄·12H₂O. Syntheses (1) and (2) gave products as reversibly softening and soluble materials, whereas synthesis (3) produced partially cross-linked resins from which a soluble material might be extracted. Polycondensation using borax gave polymers and copolymers with incorporated boron atoms. The polysilsesquioxanes were characterized by size exclusion chromatography (SEC), ¹H and ²⁹Si NMR, IR spectroscopy, and elemental analysis. Thermal properties were studied by DSC and thermogravimetry.     

Evolution of the distribution function of the composition of oxide inclusions for the growth model of a disperse system formed during deoxidation

The growth model for nuclei of oxide inclusions growing during the process of steel deoxidation is proposed. The evolution of the inclusion composition has been analysed by solving the continuity equation for the probability-density function f(x,t) (where x is the oxide mole fraction). The calculations were carried out for model parameters and for steel deoxidation by aluminium or silicon-manganese. The result obtained cannot be verified due to the lack of any functional dependence relating chemical composition to inclusion radius.     

Amino acid profile of raw and as-eaten products of spinach (Spinacia oleracea L.)

The aim of the work was to evaluate the amino acid composition of fresh spinach and spinach products prepared for consumption. The investigation included fresh and cooked spinach and two kinds of frozen product: one obtained using the traditional method (blanching-freezing-refrigerated storage) and then cooked; and the other, of the ready-to-eat type, obtained using the modified method (cooking-freezing-refrigerated storage) and then prepared for consumption in a microwave oven. In 100 g of edible parts of the as-eaten products, the content of amino acids exceeded that in the raw material from which they were obtained, except for sulphur amino acids and tyrosine. In the as-eaten products, the content of amino acids in protein calculated in 16 g N was similar to that in the raw material, except for lower tyrosine and higher arginine content in the traditional frozen product prepared for consumption. Cystine with methionine was the amino acid limiting the quality of protein in the investigated samples, except for the traditional frozen product prepared for consumption, where the Chemical Score (CS) index was 100.     

Total and soluble oxalate content in legume vegetables used in the preparation of frozen products for consumption

The aim of the investigation was to compare oxalate retention in two types of frozen product prepared for consumption after frozen storage: one obtained using the traditional method (blanching‐freezing‐frozen storage‐cooking) and a convenience food involving cooking‐freezing‐frozen storage‐defrosting and heating in microwave oven. The investigation included three species of legume vegetables: immature (wax‐stage maturity) seeds of broad bean and green pea, and French bean. Fresh broad bean seeds contained 53 mg total oxalates in 100 g fresh matter; pea 38 mg; and French bean 88 mg. Soluble oxalates comprised 53, 58 and 72% of total oxalates. The treatments applied resulted in reduction of the level of total and soluble oxalates, and oxalate to calcium ratio (broad bean and French bean); there was no influence on the level of calcium bound as calcium oxalate; true retention of oxalates was lower than apparent retention (green pea and French bean).     

Structural changes during crystallization of apatite and wollastonite in the eutectic glass of Ca3(PO4)2‐CaSiO3 system

In this study, a bioactive glass of eutectic composition based on Ca₃(PO₄)₂‐CaSiO₃ system was prepared and investigated. It was found that by controlling the nucleation and growth of crystals, a glass‐ceramics free from cracks, containing one or two crystalline phases, and of controlled nano‐ to microscale microstructure can be obtained. Heat treatment of the parent glass produces various calcium phosphates (Ca‐deficient apatite and α‐tricalcium phosphate) and calcium silicates (pseudo‐wollastonite and/or wollastonite‐2M) plus amorphous phases. By combining a number of experimental techniques like ³¹P and ²⁹Si magic angle spinning nuclear magnetic resonance spectroscopy, scanning and transmission electron microscopy, energy‐dispersive X‐ray spectrometry, and Rietveld analysis of X‐ray diffraction patterns, a crystallization model was derived, capable of explaining the observed structural and microstructural changes. The determination of amorphous or crystalline phases enabled to produce time‐temperature‐transformation plots. The structural role on the behavior of these materials and its impact on their in vitro bioactivity are also discussed.     

Changes in the level of vitamin C,beta-carotene,thiamine, and riboflavin during preservation of immature grass pea (<Emphasis Type="Italic">Lathyrus sativus L</Emphasis>.) seeds

The aim of the work was to evaluate the content of vitamin C, beta-carotene, thiamine, and riboflavin in raw and preserved physiologically immature grass pea seeds. The seeds of the cultivar Krab, differing in their morphology, phytometric traits, and specific gravity were divided into four stages of maturity, which corresponded to the following levels of their dry matter content: I - 25.9, II - 30.1, III - 36.4, and IV 40.6 g/100 g. The evaluation was conducted at the stage of the raw material, the material after blanching, frozen seeds after 6-month storage before and after cooking to the consumption consistency, and canned seeds 6 months after production. With the maturity degree of grass pea seeds the content of vitamin C was reduced by 19%, beta-carotene by 29%, riboflavin by 20%, while that of thiamine increased by 97%. The blanching of seeds led to a statistically significant decrease only in the content of vitamin C. Freezing and frozen storage did not significantly affect the level of the analysed components. The cooking of frozen seeds, the preservation of canned products, and their storage significantly reduced the content of all the analysed components in all the samples. No dependence was found between the magnitude of decreases in the investigated compounds and the degree of seed maturity. After cooking frozen seeds prepared from the raw material at the same maturity degree as the canned product contained 32%-51% more vitamin C, 0%-8% more beta-carotene, 40%-97% more thiamine, and 20%-25% more riboflavin, depending on the degree of seed maturity.     

Use of ozone to reduce molds in a cheese ripening room

Cheese ripening rooms have an unusual environment, an environment that encourages mold growth. Ozone has been applied in various ways in the food industry. One useful advantage of ozone is that it inactivates molds. In this study, a cheese ripening room was ozonated, and the effectiveness of this treatment was evaluated both in air and on surfaces through sampling on a weekly basis over a 3-month period. The results obtained indicate that ozone treatment reduced the viable airborne mold load but did not affect viable mold on surfaces. Only by wiping the surfaces with a commercial sanitizer was it possible to decrease the viable mold load on surfaces. To improve overall hygiene in the ripening room, a combination of cleaning regimes is recommended. The mold genera occurring most frequently in the air of the cheese ripening room were Penicillium, Cladosporium, and Aspergillus, which accounted for 89.9% of the mold isolates. Penicillium and Aspergillus were identified to the species level, and data showed that P. brevicompactum and P. aurantiogriseum, as well as A. versicolor, were the species most frequently isolated.     

Comparison of the contents of the main antioxidant compounds and the antioxidant activity of white grapefruit and his new hybrid

The aim of this study was to compare the main antioxidant compounds content and the antioxidant activity of white grapefruit and his new hybrid (Jaffa Sweeties). Total phenols were measured colorimetrically using the Folin-Ciocalteu reagent, phenolic acids—by HPLC, anthocyanins and flavonoids—spectrophotometrically. The antioxidant activity of these fruits was determined by total antioxidant activity (TAA) and nitric oxide (NO) methods. Trans-hydroxycinnamic acids (caffeic, p-coumaric, ferulic, and sinapic) were more abundant in white grapefruit than in his hybrid. However, on a fresh weight basis, grapefruit's hybrid has a higher total phenol content as well as a higher antioxidant capacity in comparison with white grapefruit. A linear relationship existed between TAA and anthocyanins (R²=0.8068), TAA and flavonoids (R²=0.9320) and TAA and total phenols (R²=0.9446). Our findings indicate the following: (1) Both studied fruits contain a high concentration of natural antioxidants that have not only a high antioxidant activity, but also a good antioxidant quality. (2) The total phenol content and the antioxidant potential are significantly higher in the grapefruit hybrids than in white grapefruits.     

Effect of freezing and canning on the content of selected vitamins and pigments in seeds of two grass pea (Lathyrus sativus L.) cultivars at the not fully mature stage

Seeds of the grass pea (Lathyrus sativus L.) cultivars Derek and Krab, with a dry matter content of about 33%, were used for freezing and for canning. The content of vitamins C, B1, and B2 and of carotenoids, beta-carotene, and chlorophylls was determined in raw and blanched material, in frozen products after 6-month storage before and after cooking to consumption consistency, and in canned products after 6-month storage. In comparison with the cultivar Krab, raw seeds of Derek contained 45% more vitamin C, 14% more total chlorophylls, 13% less thiamine (vitamin B1), and 7% less riboflavin (vitamin B2). The level of carotenoids was similar. Blanching of seeds led to a statistically significant decrease only in the content of vitamin C. Freezing and frozen storage significantly lowered the level of vitamin C and chlorophylls. The cooking of frozen seeds and the production of canned products and their storage resulted in a statistically verified reduction in the content of components analysed in all the samples. Greater losses were found in products prepared from seeds of the cv. Krab. After cooking, frozen seeds contained more of all the analysed components than the canned products.