The fine structure of "resting bodies" of Bdellovibrio sp. strain W developed in Rhodospirillum rubrum

1972 ◽  
Vol 18 (1) ◽  
pp. 87-92 ◽  
Author(s):  
Judith F. M. Hoeniger ◽  
Rita Ladwig ◽  
Hans Moor
Keyword(s):  
Outer Layer ◽  
Liquid Culture ◽  
Rhodospirillum Rubrum ◽  
Amorphous Material ◽  
Thin Sections ◽  
Host System ◽  
E Coli ◽  
Storage Granules ◽  
And Storage ◽  
Escherichia Coli B

Resting bodies of Bdellovibrio sp. strain W were produced following the infection of Rhodospirillum rubrum in liquid culture. Thin sections showed that young resting bodies possessed a narrow layer of amorphous material at their periphery, and storage granules in the region of the nucleoplasm. In mature resting bodies, the amorphous material (now called the outer layer) had thickened considerably to 30–40 nm, and the cell wall had differentiated into a folded, tripartite inner layer. Freeze-etched preparations of mature resting bodies showed a roughly particulate plasma membrane, a more finely particulate inner layer, and an outer layer having little structure.Bdellovibrio W did not produce resting bodies in a second host, Escherichia coli B. Also B. bacteriovorus strain 109 failed to form resting bodies in E. coli B, its usual host. It also failed to grow in cultures of R. rubrum. These restricted experiments suggest that the development of resting bodies may be specific for the Bdellovibrio W – R. rubrum parasite–host system.

scholarly journals Cysteine proteinases in rat parathyroid cells with special reference to their correlation with parathyroid hormone (PTH) in storage granules.

1993 ◽  
Vol 41 (2) ◽  
pp. 273-282 ◽  
Author(s):  
Y Hashizume ◽  
S Waguri ◽  
T Watanabe ◽  
E Kominami ◽  
Y Uchiyama
Keyword(s):  
Electron Microscopy ◽  
Parathyroid Hormone ◽  
Special Reference ◽  
Secretory Granules ◽  
Cysteine Proteinases ◽  
Double Immunostaining ◽  
Thin Sections ◽  
Storage Granules ◽  
Golgi Network ◽  
And Storage

To further understand the roles of storage granules in parathyroid cells, we examined by immunocytochemistry the localization of cathepsins B and H and of PTH in rat parathyroid gland. In semi-thin sections, small and large granular immunodeposits for cathepsins B and H appeared in the cells, whereas those for PTH were detected throughout the cells, especially in perinuclear regions. By electron microscopy, immunogold particles indicating cathepsins B and H labeled lysosomes and storage granules, whereas those showing PTH were localized in storage granules, small secretory granules, and the trans-Golgi network. Small vesicles labeled by immunogold particles showing these proteinases often appeared close to the storage granules. By double immunostaining, immunogold particles indicating these proteinases were co-localized with those for PTH in storage granules. By EDTA treatment, immunoreactivity for cathepsins B and H and for PTH was notably reduced in the cells, but immunoreactivity for the proteinases was still seen in lysosomes. These results suggest that storage granules in the rat parathyroid cells fuse with small vesicles containing cathepsins B and H, which may participate in regulating the intracellular PTH levels by degrading PTH in the granules.

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

scholarly journals Highly absorbent hydrogels comprised from interpenetrated networks of alginate–polyurethane for biomedical applications

2021 ◽  
Vol 32 (6) ◽  
Author(s):  
Jesús A. Claudio-Rizo ◽  
Nallely Escobedo-Estrada ◽  
Sara L. Carrillo-Cortes ◽  
Denis A. Cabrera-Munguía ◽  
Tirso E. Flores-Guía ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Degradation Rate ◽  
High Capacity ◽  
Hydrolytic Degradation ◽  
Absorption Capacity ◽  
Amide Bonds ◽  
E Coli ◽  
Swelling Capacity ◽  
And Storage ◽  
Potential Area

AbstractDeveloping new approaches to improve the swelling, degradation rate, and mechanical properties of alginate hydrogels without compromising their biocompatibility for biomedical applications represents a potential area of research. In this work, the generation of interpenetrated networks (IPN) comprised from alginate–polyurethane in an aqueous medium is proposed to design hydrogels with tailored properties for biomedical applications. Aqueous polyurethane (PU) dispersions can crosslink and interpenetrate alginate chains, forming amide bonds that allow the structure and water absorption capacity of these novel hydrogels to be regulated. In this sense, this work focuses on studying the relation of the PU concentration on the properties of these hydrogels. The results indicate that the crosslinking of the alginate with PU generates IPN hydrogels with a crystalline structure characterized by a homogeneous smooth surface with high capacity to absorb water, tailoring the degradation rate, thermal decomposition, and storage module, not altering the native biocompatibility of alginate, providing character to inhibit the growth of E. coli and increasing also its hemocompatibility. The IPN hydrogels that include 20 wt.% of PU exhibit a reticulation index of 46 ± 4%, swelling capacity of 545 ± 13% at 7 days of incubation at physiological pH, resistance to both acidic and neutral hydrolytic degradation, mechanical improvement of 91 ± 1%, and no cytotoxicity for monocytes and fibroblasts growing for up to 72 h of incubation. These results indicate that these novel hydrogels can be used for successful biomedical applications in the design of wound healing dressings.

scholarly journals Transport and storage of serotonin by thrombin-treated platelets.

1975 ◽  
Vol 65 (2) ◽  
pp. 359-372 ◽  
Author(s):  
H J Reimers ◽  
D J Allen ◽  
I A Feuerstein ◽  
J F Mustard
Keyword(s):  
Storage Capacity ◽  
Platelet Membrane ◽  
Transport Rate ◽  
Primary Reason ◽  
High Concentration ◽  
Serotonin Content ◽  
Amine Storage ◽  
Storage Granules ◽  
And Storage ◽  
Amine Storage Granules

Repeated thrombin treatment of washed platelets prepared from rabbits can decrease the serotonin content of the platelets by about 80%. When these platelets are deaggregated they reaccumulate serotonin but their storage capacity for serotonin is reduced by about 60%. If thrombin-pretreated platelets are allowed to equilibrate with a high concentration of serotonin (123 mu M), they release a smaller percentage of their total serotonin upon further thrombin treatment, in comparison with the percentage of serotonin released from control platelets equilibrated with the same concentration of serotonin calculations indicate that in thrombin-treated platelets reequilibrated with serotonin, two-thirds of the serotonin is in the granule compartment and one-third is in the extragranular compartment, presumably the cytoplasm. Analysis of the exchange of serotonin between the suspending fluid and the platelets showed that thrombin treatment does not alter the transport rate of serotonin across the platelet membrane and does not cause increased diffusion of serotonin from the platelets into the suspending fluid. The primary reason for the reduced serotonin accumulation by the thrombin-treated platelets appears to be loss of amine storage granules or of the storage capacity within the granules.

One-Step Preparation of Competent E. coli: Transformation and Storage of Bacterial Cells in the Same Solution

2021 ◽  
Vol 2021 (11) ◽  
pp. pdb.prot101212 ◽  
Author(s):  
Michael R. Green ◽  
Joseph Sambrook
Keyword(s):  
Escherichia Coli ◽  
Convenient Method ◽  
Plasmid Dna ◽  
Transformation Efficiency ◽  
Bacterial Cells ◽  
E Coli ◽  
One Step ◽  
And Storage

This protocol describes a convenient method for the preparation, use, and storage of competent Escherichia coli. The reported transformation efficiency of this method is ∼5 × 107 transformants/µg of plasmid DNA.

scholarly journals Improving laboratory control of butter

2019 ◽  
Vol 14 (2) ◽  
pp. 170-178
Author(s):  
Ivan Georgievich Seregin ◽  
Dmitry Vladimirovich Nikitchenko ◽  
Leonid Borisovich Leontiev ◽  
Olga Andreevna Akulich
Keyword(s):  
Milk Fat ◽  
Social Relation ◽  
Storage Conditions ◽  
Hot Water ◽  
Chain Stores ◽  
E Coli ◽  
Safety Requirements ◽  
Laboratory Control ◽  
The Social ◽  
And Storage

The work is devoted to the improvement of laboratory control of cow butter, which is sold in the chain stores and markets. The social relation of buyers to butter, its range in various retailers are studied, and samples of the butter, acquired in chain stores and markets of Moscow and Vladimir, are investigated. During microbiological studies, the presence of E. coli in the butter “Krestianskoe” was established, which does not meet the safety requirements of this product. In addition, in this butter was revealed a reduced content of milk fat 71.5% instead of 72.5%. Butter “Shokoladnoe” of the “Krestianskoe” trademark had only 60% of fat content, instead of the declared 62%. The packaging of this oil is marked with a distorted label according to the shelf life and storage conditions, which indicates information falsification. There is a mismatch in selected samples with the requirements of GOST and the stated indicators, which indicates the need to develop additional methods for identifying various fakes in butter. It was determined that by melting butter in hot water, by microscopying a product using a compressor or by irradiating the surface of butter with UV rays, it is possible to quickly and reliably identify some of its falsifications.

scholarly journals KEBERADAAN MIKROBA PADA BAKSO IKAN ASAP CAIR, YANG DIKEMAS DALAM RETORTABLE POUCH, DIPASTEURISASI DAN DISIMPAN PADA TEMPERATUR RUANG

2016 ◽  
Vol 4 (2) ◽  
pp. 85
Author(s):  
Margani Luyuani Rohana ◽  
Siegfried Berhimpon ◽  
Joyce CV Palenewen
Keyword(s):  
Shelf Life ◽  
Water Content ◽  
Experimental Method ◽  
Room Temperature ◽  
Plate Count ◽  
E Coli ◽  
Existing Problems ◽  
Liquid Smoke ◽  
Total Plate Count ◽  
And Storage

A research has been done to assess the presence of microbes and the shelf life of fish balls dipped in liquid smoke, packed in retortable pouch, pasteurized, and stored at room temperature. The method used in this research is an experimental method that revealed the facts based on existing problems through hypothesis testing. Parameters assessed are Total Plate Count (TPC), total Salmonella, total coliforms and E. coli, total vibrio, water content, and pH. Fish balls were pasteurized in 85ºC and stored in room temperature for 0, 3, 6, and 9 days, and were pasteurized at 100°C and storage in room temperature for 0, 9, 18, and 27 days. The results shown that all pathogen were negative, but based on Indonesian standard (SNI 01-7266-1-2006) especially TPC value, fish balls were packaged in retortable pouch and without pasteurized is no longer acceptable for consumption after 3 days of storage, and fish balls were packaged in retortable pouch and pasteurized at 85ºC no longer acceptable for consumed after 6 days of storage. While the fish balls are packaged in retortable pouch and pasteurized at 100°C is no longer acceptable for consumed after 18 days of storage.Keyword: Retortable Pouch, Pasteurization, Pathogens.  Penelitian ini bertujuan untuk mengetahui keberadaan mikroba dan daya awet bakso ikan yang direndam dalam asap cair dan dikemas dalam Retortable pouch, dipasteurisasi, dan disimpan pada temperatur ruang. Metode yang digunakan dalam penelitian ini adalah metode eksperimen untuk menguji hipotesa. Parameter yang diamati yaitu Angka Lempeng Total (ALT), Salmonella, total koliform dan E.coli, total vibrio, analisa kadar air, dan nilai pH. Bakso ikan asap cair yang dipasteurisasi pada 85ºC, disimpan pada temperatur ruang selama 0, 3, 6, dan 9 hari, dan yang dipasteurisasi pada 100ºC, disimpan pada temperatur ruang selama 0,9,18, dan 27 hari. Hasil penelitian menunjukkan bahwa bakso ikan yang dikemas dalam Retortable pouch, tanpa dipasteurisasi sudah tidak layak lagi untuk dikonsumsi setelah penyimpanan 3 hari, dan bakso ikan yang dikemas dalam Retortable pouch dan dipasteurisasi pada 85ºC sudah tidak layak lagi untuk dikonsumsi setelah penyimpanan 6 hari. Bakso ikan yang dikemas dalam Retortable pouch, dan dipasteurisasi pada 100ºC nanti tidak layak lagi dikonsumsi setelah penyimpanan 18 hari.Kata Kunci: Kemasan Retortable Pouch, Pasteurisasi, Patogen.

scholarly journals Modification by an R determinant for streptomycin of hissd phenotype in a mutant strain of Escherichia coli B

1968 ◽  
Vol 12 (2) ◽  
pp. 109-116 ◽  
Author(s):  
A. M. Molina ◽  
L. Calegari ◽  
G. Conte
Keyword(s):  
Escherichia Coli ◽  
Cell Membrane ◽  
Mutant Strain ◽  
Minimal Medium ◽  
Specific Requirement ◽  
Resistance Level ◽  
E Coli ◽  
Level Characteristic ◽  
Escherichia Coli B

When an R determinant for streptomycin is transferred into a conditionally streptomycin-dependent E. coli B mutant—which requires in minimal medium either histidine or streptomycin—the latter behaves like a histidineless strain. This phenotype modification shows that the repairing action of streptomycin is prevented. The specific requirement of the strain is not now replaced even by streptomycin concentrations up to 10000 µg/ml at which the conditionally streptomycin-dependent mutant could originally grow, and which are well beyond the resistance level characteristic of the R determinant itself. These data seem to suggest that a reduction in permeability of the cell membrane cannot be held responsible for the phenomenon observed.

Electron microscopic observations on the development and cytochemistry of the large granule complexes in chicken erythrocyte nuclei

1982 ◽  
Vol 55 (1) ◽  
pp. 157-187
Author(s):  
E.C. Pearson ◽  
H.G. Davies
Keyword(s):  
Amorphous Material ◽  
Ultrastructural Feature ◽  
Amorphous Region ◽  
Chicken Erythrocyte ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Large Granule ◽  
Erythrocyte Nucleus ◽  
Chicken Erythrocytes

Large granule complexes are structures found in a small percentage of chicken erythrocyte nuclei when observed in ultra-thin sections in the electron microscope. They consist of an amorphous region associated with a number of large (approximately 30 min) granules. We have shown, by a novel use of phenylhydrazine to synchronize populations of chicken erythrocytes in vivo, that large granule complexes do not occur in the nuclei until the cells have reached one-third to one-half of their normal intravascular lifespan. The mature large granule complexes are formed by aggregation of pre-existing fibrillar, granular and amorphous material, and their presence is correlated with the presence of another ultrastructural feature of the nucleus, the so-called “filled cavities' in the chromatin. Digestion of ultra-thin sections of erythrocytes embedded in the hydrophilic resin glycol methacrylate (GMA) has shown that the major component of the amorphous region is a rather acidic protein that is not haemoglobin, the most abundant protein in the erythrocyte. The large granules also contain protein and, almost certainly, RNA. The problems encountered in reaching this conclusion have emphasized the lack of unambiguous cytochemical tests for use on ultra-thin sections. We have shown that the large granule complex differs in many respects from the nucleolus in the erythrocyte series, even though the two organelles have certain superficial similarities such as their overall dimensions and the presence of granular and fibrillar regions. The most likely function of the large granule complex is as a repository for material, including RNA, the processing of which has ceased in the inactivated erythrocyte nucleus.

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