scholarly journals In vitro fibrillogenesis of collagen II from pig vitreous humour

1995 ◽  
Vol 306 (3) ◽  
pp. 871-875 ◽  
Author(s):  
C Yang ◽  
H Notbohm ◽  
Y Açil ◽  
R Heifeng ◽  
S Bierbaum ◽  
...  
Keyword(s):  
Cross Sections ◽  
Soluble Fraction ◽  
Unit Length ◽  
Insoluble Fraction ◽  
Vitreous Humour ◽  
Collagen Types ◽  
Collagen Molecules ◽  
Collagen Ii

Collagen from pig vitreous humour was fractionated into a soluble and an insoluble fraction by centrifugation. Most of the collagen II in the soluble fraction was present as pN-collagen II (procollagen II without the C-terminal propeptide), besides smaller quantities of procollagen II, collagen II and two as yet unidentified alpha-chains of collagen II. Other collagen types may be present only in trace amounts. Collagen II of the insoluble fraction, which is mostly deposited in fibrillar aggregates, consists of both pN-collagen II and collagen II. To determine the possible role of collagen II precursors in the formation of the extracellular matrix of the vitreous humour these collagen molecules were purified and in vitro fibrillogenesis was used to demonstrate that pN-collagen II could form fibrils in mixtures with collagen II. These fibrils have a reduced mass per unit length depending on the content of pN-collagen in the mixture. Cross-sections of the newly formed fibrillar aggregates revealed a flattened shape. The incomplete processing of the precursors of collagen II may be part of regulatory mechanisms possibly controlling the formation of a translucent scaffold as is required in the vitreous humour.

ROLE OF FIBRONECTIN AND COLLAGEN TYPES I AND II IN CHONDROCYTIC DIFFERENTIATION IN VITRO

1978 ◽  
Vol 312 (1 Fibroblast Su) ◽  
pp. 404-405 ◽  
Author(s):  
W. Dessau ◽  
J. Sasse ◽  
R. Timpl ◽  
K. Mark
Keyword(s):  
Collagen Types ◽  
Chondrocytic Differentiation

scholarly journals Recruitment of the γ-Tubulin Ring Complex to Drosophila Salt-stripped Centrosome Scaffolds

1998 ◽  
Vol 142 (3) ◽  
pp. 775-786 ◽  
Author(s):  
Michelle Moritz ◽  
Yixian Zheng ◽  
Bruce M. Alberts ◽  
Karen Oegema
Keyword(s):  
Soluble Fraction ◽  
Protein Complexes ◽  
Drosophila Embryo ◽  
Microtubule Nucleation ◽  
Complementation Assay ◽  
Embryo Extract ◽  
Ring Complex ◽  
Centrosomal Proteins

Extracting isolated Drosophila centrosomes with 2 M KI generates salt-resistant scaffolds that lack the centrosomal proteins CP190, CP60, centrosomin, and γ-tubulin. To clarify the role of these proteins in microtubule nucleation by centrosomes and to identify additional centrosome components required for nucleation, we have developed an in vitro complementation assay for centrosome function. Centrosome aster formation is reconstituted when these inactive, salt-stripped centrosome scaffolds are supplemented with a soluble fraction of a Drosophila embryo extract. The CP60 and CP190 can be removed from this extract without effect, whereas removing the γ-tubulin destroys the complementing activity. Consistent with these results, we find no evidence that these three proteins form a complex together. Instead, γ-tubulin is found in two distinct protein complexes of 240,000 and ∼3,000,000 D. The larger complex, which is analogous to the Xenopus γ-tubulin ring complex (γTuRC) (Zheng, Y., M.L. Wong, B. Alberts, and T. Mitchison. 1995. Nature. 378:578–583), is necessary but not sufficient for complementation. An additional factor found in the extract is required. These results provide the first evidence that the γTuRC is required for microtubule nucleation at the centrosome.

scholarly journals Enzyme activity after resealing within ghost erythrocyte cells, and protection by α-crystallin against fructose-induced inactivation

2002 ◽  
Vol 368 (3) ◽  
pp. 865-874 ◽  
Author(s):  
Barry K. DERHAM ◽  
John J. HARDING
Keyword(s):  
Enzyme Activity ◽  
Molecular Chaperone ◽  
Soluble Fraction ◽  
Erythrocyte Ghosts ◽  
Ghost Cell ◽  
Chaperone Function ◽  
Zero Time ◽  
Soluble Fractions

The role of α-crystallin as a molecular chaperone has been shown in many in vitro studies. In the present paper, we report on the chaperone function of α-crystallin within resealed erythrocyte ghosts. Eight enzymes were individually resealed within erythrocyte ghosts and assayed at zero time and at 24h. The ghost cell suspension was separated into soluble and membrane fractions. Five of the enzymes had significantly greater enzyme activity after 24h than the control within the soluble fractions. Fructation caused a decrease in enzyme activity (relative to the control). Resealing of α-crystallin within the ghost cell alongside the enzymes protected against inactivation by fructose within the soluble fraction.

scholarly journals Fermentation kinetics and in vitro degradation rates of grasses of the genus Cynodon

2016 ◽  
Vol 38 (3) ◽  
pp. 249 ◽  
Author(s):  
Sidnei Tavares dos Reis ◽  
Marcus Vinícius Gonçalves Lima ◽  
Eleuza Clarete Junqueira de Sales ◽  
Flávio Pinto Monção ◽  
João Paulo Sampaio Rigueira ◽  
...  
Keyword(s):  
Dry Matter ◽  
Soluble Fraction ◽  
Insoluble Fraction ◽  
Gas Production ◽  
Subsequent Reduction ◽  
Fermentation Kinetics ◽  
In Vitro Gas Production ◽  
Degradation Rates ◽  
Automated Technique

The present study aimed to evaluate the fermentation kinetics and degradation rates of Cynodon grasses estimated by semi-automated technique of in vitro gas production. The forages were: Coastcross, Tifton 85 and Tifton 68. Pressure readings were taken at 0, 2, 4, 6, 8, 10, 12, 15, 19, 24, 30, 36, 48, 72 and 96 hours. Dry matter degradability (DMD) was obtained by the percentage of dry matter (DM) remaining after 0, 6, 12, 24, 48 and 96 hours of fermentation. Tifton 85 showed a higher total gas production (p <0.05). Higher fermentation rates were found at the beginning of fermentation followed by subsequent reduction (p <0.05) over time. Tifton 85 and Tifton 68 showed higher values (p < 0.05) for soluble fraction, potentially degradable insoluble fraction, insoluble fraction, potential and effective degradability of dry matter in relation to Coastcross grass. Higher gas production during in vitro incubation of dry matter was observed for Tifton 85 g. 

Peripheral nerve as an osmometer: role of the perineurium in frog sciatic nerve

1983 ◽  
Vol 244 (1) ◽  
pp. C75-C81 ◽  
Author(s):  
P. Ask ◽  
H. Levitan ◽  
P. J. Robinson ◽  
S. I. Rapoport
Keyword(s):  
Hydrostatic Pressure ◽  
Sciatic Nerve ◽  
Unit Length ◽  
Elastic Tissue ◽  
A Value ◽  
Pathological Conditions ◽  
Frog Sciatic Nerve ◽  
Pressure Fall

Measurements of volume and hydrostatic pressure in the frog sciatic nerve in vitro demonstrate that the nerve acts as an osmometer, in large part because the perineurium is a semipermeable membrane for water flow. Endoneurial hydrostatic pressure in nerves in isotonic Ringer exceeds bath pressure by about 7 mmHg. In Ringer made hypertonic by addition of sucrose, nerve volume and endoneurial pressure fall linearly in relation to 1/osmolality. The slope of the plot of pressure against volume provides a value for nerve compliance equal to 0.006 mm2/mmHg. Calculations based on the model of the nerve as an osmometer indicate that the nerve has an osmotically "inactive" volume equal to 0.19 mm3/mm, which is about 75% of the total volume of a nerve segment of unit length in normal Ringer. Perineurial hydraulic conductivity (Lp) equals 7.5 x 10(-13) cm3.s-1.dyn-1, a value characteristic of nonleaky epithelia. The perineurium is an elastic tissue with a constant modulus of elasticity equal to 3 x 10(6) dyn/cm2 when not markedly stretched and may limit nerve swelling under pathological conditions of nerve edema.

scholarly journals Role of gelsolin in actin depolymerization of adherent human neutrophils.

1997 ◽  
Vol 8 (1) ◽  
pp. 121-128 ◽  
Author(s):  
J S Wang ◽  
J P Coburn ◽  
A I Tauber ◽  
K S Zaner
Keyword(s):  
Soluble Fraction ◽  
Signal Transduction Pathway ◽  
Insoluble Fraction ◽  
Actin Binding ◽  
Human Neutrophils ◽  
Nonreceptor Tyrosine Kinase ◽  
Actin Depolymerization ◽  
Herbimycin A ◽  
Triton X

Human neutrophils generally function adherent to an extracellular matrix. We have previously reported that upon adhesion to laminin- or fibronectin-coated, but not uncoated, plastic there is a depolymerization of actin in neutrophils. This phenomenon was not affected by inhibitors of the more well-studied components of the signal transduction pathway, specifically, pertussis toxin, an inhibitor of G-proteins, H-7 or staurosporine, inhibitors of protein kinase C, or herbimycin A, an inhibitor of nonreceptor tyrosine kinase. We therefore focused our attention on actin-binding proteins and measured the changes in the partitioning of gelsolin between the Triton X-100-soluble and -insoluble cellular fractions which occur upon neutrophil adhesion by means of quantitating anti-gelsolin antibody binding to aliquots of these fractions. It was found that approximately 90% of the total cellular gelsolin was found in the Triton X-100-soluble fraction in suspended cells, but that upon adherence to either fibronectin- or laminin-coated plastic about 40% of the soluble gelsolin could be detected in the insoluble fraction. This effect was not observed in cells adherent to uncoated plastic, wherein more than 90% of the gelsolin was found in the soluble fraction. Results of immunofluorescence microscopy of these cell preparations was consistent with this data. A gelsolin translocation to the insoluble cellular actin network may account for a part of the observed actin depolymerization.

scholarly journals In Vitro Expanded Bioaccessibility of Quercetin-3-Rutinoside and Quercetin Aglycone from Buckwheat Biscuits Formulated from Flours Fermented by Lactic Acid Bacteria

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 571
Author(s):  
Henryk Zieliński ◽  
Wiesław Wiczkowski ◽  
Joanna Honke ◽  
Mariusz Konrad Piskuła
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Liquid State ◽  
Soluble Fraction ◽  
Insoluble Fraction ◽  
Lower Content ◽  
Gastrointestinal Digestion ◽  
High Q ◽  
Quercetin Aglycone

The expanded bioaccessibility of rutin (Ru) and quercetin (Q) from buckwheat biscuits (BBs) formulated from liquid-state fermented flours by selected lactic acid bacteria (LAB) were determined after gastrointestinal digestion. Fermentation of buckwheat flours caused a LAB-dependent variation in Ru and Q content. BBs baked at 220 °C for 30 min showed lower content of Ru and Q, and no correlation was found between the content of these compounds in fermented flours and BBs. The expanded bioaccessibility of Ru from BBs was low when its content in the soluble and insoluble fractions remaining after digestion in vitro was taken into account. Contrary results were found for Q bioaccessibility which had an index greater than 1, indicating the high Q bioaccessibility from BBs. Since very low Q content was noted in the insoluble fraction remaining after BBs digestion, the high Q bioaccessibility was determined to be due to its concentration in the soluble fraction.

scholarly journals Yeast Mpo1 Is a Novel Dioxygenase That Catalyzes the α-Oxidation of a 2-Hydroxy Fatty Acid in an Fe2+-Dependent Manner

2018 ◽  
Vol 39 (5) ◽  
Author(s):  
Naoya Seki ◽  
Keisuke Mori ◽  
Takuya Kitamura ◽  
Masatoshi Miyamoto ◽  
Akio Kihara
Keyword(s):  
Fatty Acid ◽  
Metabolic Pathway ◽  
Oxidation Reaction ◽  
Soluble Fraction ◽  
Dependent Manner ◽  
The Novel ◽  
Content Type ◽  
Long Chain Base

ABSTRACT Phytosphingosine (PHS) is the major long-chain base component of sphingolipids in Saccharomyces cerevisiae. The PHS metabolic pathway includes a fatty acid (FA) α-oxidation reaction. Recently, we identified the novel protein Mpo1, which is involved in PHS metabolism. However, the details of the FA α-oxidation reaction and the role of Mpo1 in PHS metabolism remained unclear. In the present study, we revealed that Mpo1 is involved in the α-oxidation of 2-hydroxy (2-OH) palmitic acid (C16:0-COOH) in the PHS metabolic pathway. Our in vitro assay revealed that not only the Mpo1-containing membrane fraction but also the soluble fraction was required for the α-oxidation of 2-OH C16:0-COOH. The addition of Fe2+ eliminated the need for the soluble fraction. Purified Mpo1 converted 2-OH C16:0-COOH to C15:0-COOH in the presence of Fe2+, indicating that Mpo1 is the enzyme body responsible for catalyzing the FA α-oxidation reaction. This reaction was also found to require an oxygen molecule. Our findings indicate that Mpo1 catalyzes the FA α-oxidation reaction as 2-OH fatty acid dioxygenase, mediated by iron(IV) peroxide. Although numerous Mpo1 homologs exist in bacteria, fungi, protozoa, and plants, their functions had not yet been clarified. However, our findings suggest that these family members function as dioxygenases.

Heterogeneity of uridine incorporation along the rabbit nephron. II. Effect of DOCA

1984 ◽  
Vol 246 (4) ◽  
pp. F427-F436
Author(s):  
A. Vandewalle
Keyword(s):  
Nucleic Acids ◽  
Soluble Fraction ◽  
Insoluble Fraction ◽  
Marked Rise ◽  
Precursor Pool ◽  
Uridine Incorporation ◽  
Uridine Uptake ◽  
Corticosteroid Hormones ◽  
Collecting Tubules

Uridine uptake was investigated in microdissected segments from the entire length of tubules from normal rabbit kidneys and the effect DOCA treatment was studied. Uridine uptake was measured after in vitro incubation of kidney pyramids with [14C]uridine (0.25 mM). Determinations were done on intact segments, and also using TCA precipitation on both the acid-soluble fraction considered as representative of the pyrimidine nucleoside precursor pool and the acid-insoluble one containing the precipitated nucleic acids. In normal rabbits the fraction of uridine incorporated in the insoluble fraction represented about 5% of that in the soluble one for all segments. Maximal values were found in the distal convoluted tubule (DCT) and the connecting tubule (CNT), where uridine uptake was two- to fourfold higher than in other segments. After DOCA treatment, a significant increase in uridine uptake in the soluble fraction was present in the cortical collecting (CCT) (+90%, P less than 0.001) and medullary collecting tubules (MCT) (+63%, P less than 0.05) when values were corrected for the cellular swelling induced by DOCA in all segments. An even more marked rise in uridine incorporation was observed in the insoluble fraction of the DCT (+88%, P less than 0.05), CCT (+291%, P less than 0.001), and MCT (+422%, P less than 0.05). These results indicate that 1) the level of uridine uptake in soluble and insoluble fractions widely differs along the tubular length of the normal rabbit nephron; and 2) DOCA treatment induces an increase of uridine incorporation in both the pyrimidine precursor pool and nucleic acids of the collecting tubule, known to be the target site for corticosteroid hormones.

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