STUDIES ON THE CHITAN (CHITIN: POLY-N-ACETYLGLUCOSAMINE) FIBERS OF THE DIATOM THALASSIOSIRA FLUVIATILIS HUSTEDT: I PRODUCTION AND ISOLATION OF CHITAN FIBERS

1965 ◽  
Vol 43 (6) ◽  
pp. 707-713 ◽  
Author(s):  
J. McLachlan ◽  
A. G. McInnes ◽  
Michael Falk
Keyword(s):  
Crystalline State ◽  
Culture Medium ◽  
Cellular Material ◽  
Subsequent Paper ◽  
Electron Microscopic ◽  
First Report

Growth of the planktonic, euryhaline diatom (Bacillariophyceae) Thalassiosira fluviatilis, both in nature and in culture, is accompanied by the production of a large amount of extracellular "mucilage". This mucilagenous condition is due to the formation of long, narrow fibers, composed of a number of microfibrils, which originate from the marginal and central pores in the silica valves. These fibers, previously referred to as mucilage or slime threads, were found upon hydrolysis to be composed entirely of glucosamine residues. Evidence will be presented in a subsequent paper (20) to show that these fibers consist entirely of pure, crystalline poly-N-acetyl-D-glucosamine linked by β-(1→4) bonds. This polymer has been given the systematic name chitan to distinguish it from chitin as isolated from other sources. This is the first report of the occurrence of this glycan in diatoms, and in a pure crystalline state in nature. The chitan was localized in the extracellular fibers, and was not found as part of the protoplasmic constituents. Approximately 18% of the nitrogen added to the culture medium was incorporated into the chitan fibers, which, in turn, comprised 31–38% of the cellular material (including the silica) of this diatom. Methods of production and isolation of the fibers are described, together with a discussion of the nature of the fibers as derived from light and electron microscopic observations. The presence of chitin in other algae also is discussed.

scholarly journals First Report of Malva vein clearing virus Naturally Occurring in Hollyhock in Germany

Plant Disease ◽  
2010 ◽  
Vol 94 (2) ◽  
pp. 276-276 ◽  
Author(s):  
W. Menzel ◽  
S. Winter ◽  
K. R. Richert-Pöggeler
Keyword(s):  
Host Range ◽  
Direct Sequencing ◽  
Amino Acid Sequences ◽  
Rt Pcr ◽  
Electron Microscopic ◽  
First Report ◽  
Vein Clearing ◽  
Naturally Occurring ◽  
Potyvirus Species ◽  
Cloned Cdna

Hollyhocks are popular garden plants and selected cultivars of Alcea rosea (family Malvaceae) are widespread in Germany. In spring 2009, dozens of A. rosea plants displaying strong vein clearing and veinal yellowing symptoms were found in private gardens in Hannover, Lower Saxony. Electron microscopic examinations of negatively stained adsorption preparations of five randomly selected samples of symptomatic plants or their offshoots revealed flexuous filamentous particles resembling those of potyviruses. Sap extracts also reacted strongly positive in an antigen coated plate (ACP)-ELISA with the broad-spectrum potyvirus antiserum AS-0573/I (DSMZ, Braunschweig, Germany). RNA extracts (RNeasy Kit, Qiagen, Valencia, CA) of the above mentioned leaf samples were used as templates in reverse transcription (RT)-PCR assays with potyvirus specific primers (2) that have been shown to amplify the 3′ terminus of the genome of many potyvirus species. For extracts from symptomatic samples, this resulted in a consistent amplification of an ~1.6-kbp fragment, whereas no products were obtained from RNA extracts of asymptomatic plants. From one positive sample, the amplified fragment was cloned and one clone was partially sequenced. The nucleotide (nt) and amino acid sequences showed the highest identities (81 to 83% and 87 to 90%, respectively) to GenBank sequences FJ539084, FM212972, EU884405, and FJ561293 of the potyvirus Malva vein clearing virus (MVCM). On the basis of these identity values and according to the species demarcation criteria in the genus Potyvirus, the virus can be regarded as a German isolate of the recently sequenced MVCV (3,4). Direct sequencing of the 5′-end of the amplified RT-PCR fragment revealed sequences of only one potyvirus species. The virus isolate has been submitted to the DSMZ Plant Virus Collection (Braunschweig, Germany) under accession PV-0963 and the sequence obtained from the cloned cDNA is deposited in GenBank (GQ856544). In addition, sap from affected leaves was mechanically inoculated onto sets of herbaceous indicator plants (Chenopodium quinoa, C. foliosum, C. murale, C. amaranticolor, Datura stramonium, Nicotiana benthamiana, N. hesperis, Petunia hybrida, and Solanum lycopersicum) of which only C. quinoa plants became infected. Symptoms of weak chlorosis along and beside veins of inoculated leaves, but not systemic leaves, became visible 2 weeks postinoculation. Symptomatic leaves contained flexuous filamentous particles and ACP-ELISA and RT-PCR confirmed virus presence. The partially sequenced amplicon showed 99% nt identity to the sequence from the cloned cDNA. To our knowledge, this is the first report of a MVCV isolate naturally occurring in A. rosea and C. quinoa is the first host identified that does not belong to the plant family Malvaceae. In contrast, the MVCV isolate used in the host range study of Lunello et al. (4) did not infect A. rosea and C. quinoa, confirming previous host range descriptions by Brunt et al. (1). Since MVCV infections of hollyhocks seem to cause only leaf symptoms and do not noticeably affect growth or flowering of the plants, this will hopefully not impair the usability of this popular garden plant. References: (1) A. A. Brunt et al. Descriptions and Lists from the VIDE Database. Online publication. Version: 16th January, 1997. (2) J. Chen et al. Arch. Virol. 146:757, 2001. (3) A. Hein Phytopathol. Z. 28:205, 1957. (4) P. Lunello et al. Virus Res. 140:91, 2009.

scholarly journals Case Reports: Disseminated Chlorellosis in a Dog

2009 ◽  
Vol 46 (3) ◽  
pp. 439-443 ◽  
Author(s):  
R. R. Quigley ◽  
K. E. Knowles ◽  
G. C. Johnson
Keyword(s):  
Lymph Nodes ◽  
Case Reports ◽  
Periodic Acid ◽  
Electron Microscopic Examination ◽  
Mesenteric Lymph Nodes ◽  
Electron Microscopic ◽  
Periodic Acid Schiff ◽  
First Report ◽  
Dense Bodies ◽  
Mesenteric Lymph

An adult dog with ataxia and a lingual mass, previously diagnosed as protothecosis, was euthanized. At the postmortem examination, the lingual mass, regions of the lungs and hilar lymph nodes, liver, mesenteric and sublumbar lymph nodes, and spinal meninges had pronounced green discoloration. Histologically, pyogranulomatous inflammation and algal organisms were found in the tongue, spinal meninges, hilar and mesenteric lymph nodes, liver, and lung. The algae had cell walls positive for periodic acid-Schiff and cytoplasmic granules. Ultrastructurally, the algae had a well-defined cell wall, stacks of grana and thylakoid membrane, and dense bodies, typical of starch granules. The organisms were identified as Chlorella, a green alga, based on the results of histochemistical and electron microscopic examination. To the author's knowledge this is the first report of disseminated Chlorella infection and the first report in a companion animal.

Folded conformations due to arene interactions in dissymmetric and symmetric butylidene-linker models based on pyrazolo[3,4-d]pyrimidine, purine and 7-deazapurine

2014 ◽  
Vol 70 (6) ◽  
pp. 555-561 ◽  
Author(s):  
Kamlakar Avasthi ◽  
Lakshmi Shukla ◽  
Ruchir Kant ◽  
Krishnan Ravikumar
Keyword(s):  
Solid State ◽  
Crystal Structures ◽  
Crystalline State ◽  
Nmr Analysis ◽  
First Report ◽  
Π Interactions ◽  
H Nmr

The butylidene-linker models 1-[2-(2,6-dimethylsulfanyl-9H-purin-9-yl)-2-methylidenepropyl]-4,6-bis(methylsulfanyl)-1H-pyrazolo[3,4-d]pyrimidine, C18H20N8S4, (XI), 7,7′-(2-methylidenepropane-1,3-diyl)bis[3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one], C20H22N6O2S2, (XIV), and 7-[2-(4,6-dimethylsulfanyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)-2-methylidenepropyl]-3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one, C19H21N7OS3, (XV), show folded conformations in solution, as shown by1H NMR analysis. This folding carries over to the crystalline state. Intramolecular π–π interactions are observed in all three compounds, but only (XIV) shows additional intramolecular C—H...π interactions in the solid state. As far as can be established, this is the first report incorporating the pyrrolo[2,3-d]pyrimidine nucleus for such a study. In addition to the π–π interactions, the crystal structures are also stabilized by other weak intermolecular C—H...S/N/O and/or S...N/S interactions.

scholarly journals Effect of Exogenous Siderophores on Iron Uptake Activity of Marine Bacteria under Iron-Limited Conditions

2001 ◽  
Vol 67 (4) ◽  
pp. 1710-1717 ◽  
Author(s):  
Le Luo Guan ◽  
Kaneo Kanoh ◽  
Kei Kamino
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Marine Bacteria ◽  
Outer Membrane Protein ◽  
Iron Uptake ◽  
Culture Medium ◽  
Paper Electrophoresis ◽  
Marine Sponges ◽  
First Report ◽  
Uptake Activity

ABSTRACT More than 60% of species examined from a total of 421 strains of heterotrophic marine bacteria which were isolated from marine sponges and seawater were observed to have no detectable siderophore production even when Fe(III) was present in the culture medium at a concentration of 1.0 pM. The growth of one such non-siderophore-producing strain, alpha proteobacterium V0210, was stimulated under iron-limited conditions with the addition of an isolated exogenous siderophore,N,N′-bis (2,3-dihydroxybenzoyl)-O-serylserine from aVibrio sp. Growth was also stimulated by the addition of three exogenous siderophore extracts from siderophore-producing bacteria. Radioisotope studies using 59Fe showed that the iron uptake ability of V0210 increased only with the addition of exogenous siderophores. Biosynthesis of a hydroxamate siderophore by V0210 was shown by paper electrophoresis and chemical assays for the detection of hydroxamates and catechols. An 85-kDa iron-regulated outer membrane protein was induced only under iron-limited conditions in the presence of exogenous siderophores. This is the first report of bacterial iron uptake through an induced siderophore in response to exogenous siderophores. Our results suggest that siderophores are necessary signaling compounds for growth and for iron uptake by some non-siderophore-producing marine bacteria under iron-limited conditions.

Clinical and histopathological characteristics of gonadotropin-producing pituitary adenomas

1985 ◽  
Vol 62 (3) ◽  
pp. 376-382 ◽  
Author(s):  
Masaki Miura ◽  
Yasuhiko Matsukado ◽  
Takafumi Kodama ◽  
Yohsuke Mihara
Keyword(s):  
Cell Culture ◽  
Culture Medium ◽  
Definitive Diagnosis ◽  
Immunoperoxidase Staining ◽  
Cell Culture Medium ◽  
Electron Microscopic ◽  
Content Type ◽  
Lh Rh ◽  
Hormonal Assay ◽  
Fine Print

✓ The clinical and histopathological characteristics in six cases of gonadotropin-producing adenoma are presented. Definitive diagnosis was made by the determination of gonadotropin levels in culture medium. Several authors have reported that gonadotropin-producing adenomas are very rare; however, hormonal assay of adenoma cell culture medium may indicate the real incidence of gonadotropin-producing adenomas to be greater than is thought. In reported cases, practically no endocrinological symptoms have been found suggesting increased gonadotropin levels, and basal values of plasma gonadotropins have been reported as only slightly over the normal range. Gonadotropin-producing adenomas may have been misdiagnosed as nonsecreting adenomas. The clinical characteristics of gonadotropin-producing adenomas can be summarized as follows: 1) a tendency for more rapid growth than nonsecreting adenomas; 2) prominent suprasellar extension with marked enhancement on computerized tomography; and 3) diminished response of luteinizing hormone (LH) alone in response to LH-releasing hormone (LH-RH) stimulation, and the ratio of peak follicle-stimulating hormone to peak LH in the LH-RH stimulation test is more frequently over 1:1 in cases of gonadotropin-producing adenoma than in cases of nonsecreting adenoma and craniopharyngioma. Immunoperoxidase staining revealed two kinds of adenoma cells, one intensely and the other faintly stained. Abundant mitochondria and few secretory granules were characteristic electron microscopic features. Oncocytic transformation of adenoma cells was suggested by immunoperoxidase staining and the electron microscopic appearance, and may suppress the elevation of circulating plasma gonadotropin levels. Thus, hormonal assay of adenoma cell culture medium and immunoperoxidase staining are essential for definitive diagnosis of gonadotropin-producing adenomas.

scholarly journals Changes in membrane-microfilament interaction in intercellular adherens junctions upon removal of extracellular Ca2+ ions.

1986 ◽  
Vol 102 (5) ◽  
pp. 1832-1842 ◽  
Author(s):  
T Volberg ◽  
B Geiger ◽  
J Kartenbeck ◽  
W W Franke
Keyword(s):  
Plasma Membrane ◽  
Phase Contrast ◽  
Culture Medium ◽  
External Surface ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Immunofluorescent Localization ◽  
Contrast Microscopy ◽  
Perinuclear Cytoplasm ◽  
Micromolar Range

EGTA-induced depletion of Ca2+ ions from the culture medium of Madin-Darby bovine kidney epithelial cells results in rapid splitting of adherens-type junctions and the detachment of the vinculin- and actin-containing filament bundle from the cytoplasmic faces of the plasma membrane of the zonula adhaerens. This process was monitored by phase-contrast microscopy, combined with electron microscopy and immunofluorescent localization of the two proteins. It is shown that shortly after extracellular free Ca2+ concentration is lowered to the micromolar range, the actin-containing, junction-associated belt of microfilaments, together with the vinculin-rich junctional plaque material, is irreversibly detached as one structural unit from the plasma membrane, contracts, and is displaced towards the perinuclear cytoplasm where it gradually disintegrates. Other actin- and vinculin-containing structures present in the same cells, notably the focal contacts at the substratum, are not similarly affected by the Ca2+ depletion and retain both the adhesion to the external surface and the association with the plaque and microfilament components. Electron microscopic examination has shown that the membrane domain of the zonulae adhaerentes, unlike that of desmosomes, is not endocytosed after Ca2+ removal and that the displaced actin- and vinculin-containing plaque and filament belt are not associated with a particular membrane. It is further shown that upon restoration of normal Ca2+ levels in the culture medium, new intercellular contacts are established gradually by accretion of both vinculin and actin into new belt-like plaque- and microfilament-containing structures.

Microwave fixation of cells in culture for scanning electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 630-631
Author(s):  
E.C. Chew ◽  
D.J. Riches ◽  
P.P.L. Tam ◽  
G.S.W. Tsao ◽  
T.K. Lam ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Suspension ◽  
Single Cell ◽  
Culture Medium ◽  
Single Cell Suspension ◽  
Electron Microscopic ◽  
Syringe Needle ◽  
Microwave Fixation ◽  
Scanning Electron

The use of microwave irradiation for fixation of human and animal tissue has been proven satisfactory at light microscopic and electron microscopic levels. The present communication reports the study of the same method of fixation of cell cultures for scanning electron microscopy.Trophoblasts were isolated from the placentae of mouse conceptuses at 10.5 days of gestation. The placenta was dissected out from the decidua and placed in Ca and Mg-free PBS, minced and then forced through a gauge-21 syringe needle. The tissue fragments were digested with 0.25% trypsin in Ca and Mg-free PBS for 20 - 30 minutes at 4°C. The digested tissue was then washed with complete PB1 medium. A single-cell suspension was obtained by spinning down the larger fragments by centrifugation. A known volume of the single-cell suspension was added to the culture medium (DCMEM and 20% FCS). The culture medium was changed after 24 hours to remove any unattached cells.

Unique method of tissue culture preparation for EM

1992 ◽  
Vol 50 (1) ◽  
pp. 728-729
Author(s):  
Fen Wang ◽  
Lindsay B. Ledford ◽  
Jonathan F. Head ◽  
Robert L. Elliott
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Cell Growth ◽  
Crystal Violet ◽  
Microscopic Examination ◽  
Culture Medium ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Unique Method ◽  
Mcf 7

A simplified technique of growing monolayer cells for electron microscopic examination has been developed. Our procedure has eliminated many difficult steps and therefore is easier than those reported by others.Regular Beem capsules for routine embedding for electron microscopy were used(Fig. 1). Prior to tissue inoculation capsules were washed with 5% HCl and gas sterilized. A 0.5 ml cell suspension of MCF-7 cells (10,000/ml) was placed in the capsules and cells settled in the pyramid portion (Fig. 2). Culture medium was alpha-MEM with 10% FCS. Capsules were incubated at 37°C for 3 days. They were then fixed in 70% ethanol for 20 minutes and stained with crystal violet. The pyramid portion of the capsule was cut off and monolayer cell growth was confirmed by examination under a microscope (Fig. 3).

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