scholarly journals A phospholipid-deacylating system of bacteria active in a frozen medium

1976 ◽  
Vol 153 (1) ◽  
pp. 49-53 ◽  
Author(s):  
G P Hazlewood ◽  
R M C Dawson

A phosphatidylcholine-deacylating system present in a Butyrivibrio species (probably fibrisolvens) shows appreciable activity at low temperatures with a maximum hydrolysis rate at—10 degrees C. 2. The rate at—10 degrees C is higher than at 39 degrees C unless the system at the latter temperature is stimulated by adding oleic acid or sodium dodecyl sulphate. 3. The low-temperature phospholipase activity has an absolute requirement for thiol reagents, e.g. cysteine, dithiothreitol or mercaptoethanol. 4. Ca2+, Mg2+ and Mn2+ stimulate the activity up to 10 mM, but EDTA inhibits; higher concentrations of Ca2+ also inhibit. 5. The enhancement of activity at low temperatures appears not to be associated with a crystalline change in the hydrated phospholipid substrate, but depends on the formation of a solid phase in the incubation medium which brings the substrate and bacterial cells into juxtaposition or causes fusion.

1973 ◽  
Vol 44 (2) ◽  
pp. 163-179 ◽  
Author(s):  
Anne M. S. Grant ◽  
A. Neuberger

1. A specific and quantitative radioimmunoassay was developed for the measurement of low concentrations of human and rabbit Tamm—Horsfall glycoprotein in the presence of other proteins. Antibody-coated tubes were used as a solid phase in the assay and the optimum antibody concentration and duration of antibody coating were established. 2. Pure Tamm—Horsfall glycoprotein was labelled with 125I and, because of its apparent susceptibility to radiation damage, was labelled at weekly intervals. 3. Sodium dodecyl sulphate, an ionic detergent, was included in the assay at a final concentration of 0.0005% to disaggregate the glycoprotein. An overnight preincubation step in the presence of the detergent was necessary before the disaggregated glycoprotein solutions were allowed to react with the antibody. Pretreatment of the tracer with detergent was not necessary. 4. Two glycoprotein standards were prepared fresh for each assay from freeze-dried material. The average linear range of the assay was between approx. 150 ng/ml and 2.5 μg/ml. Albumin was only shown to interfere with the assay at concentrations greater than 100 μg/ml. 5. Urines were dialysed against water for 3 days before assay to remove inhibitory material. Urines were never frozen as this was found to affect the assay. 6. A recovery experiment showed that the pure freeze-dried standard behaved in an immunologically identical way to the urinary glycoprotein. 7. Human Tamm-Horsfall glycoprotein cross-reacted with guinea-pig anti-(rabbit Tamm—Horsfall) antiserum and rabbit Tamm—Horsfall glycoprotein cross-reacted with guinea-pig anti-(human Tamm—Horsfall) antiserum, but not with rabbit anti-(human Tamm—Horsfall) antiserum. This showed a partial immunological identity between Tamm-Horsfall glycoprotein from humans and rabbits which was only evident when the antiserum was raised in a third species. 8. The excretion rate of Tamm—Horsfall glycoprotein in normal humans was found to be 48.1 ± 9.6 (SD) mg/24 h for males and 50.5 ± 14.8 (SD) mg/24 h for females. The mean excretion rate of the glycoprotein in New Zealand White rabbits was 34.8 ± 7.9 mg/24 h.


1982 ◽  
Vol 202 (2) ◽  
pp. 317-323 ◽  
Author(s):  
I H Mather ◽  
C H Sullivan ◽  
P J Madara

A solid-phase immunoassay was used to detect xanthine oxidase in fractions from bovine mammary glands after electrophoresis in polyacrylamide gels containing sodium dodecyl sulphate. Under these conditions the major proportion of xanthine oxidase in either mammary tissue or mild could be recovered as a protein of mol.wt. 150 000. In mammary tissue approx. 80% of the enzyme was in a soluble form and the remainder was accounted for in either ‘mitochondrial’ or microsomal fractions after tissue homogenization and fractionation. Affinity chromatography of either detergent-solubilized microsomal membranes or postmicrosomal supernatants on immobilized antibody to xanthine oxidase yielded a single protein that cross-reacted with antibody to the enzyme. In milk presumptive degradation products of the enzyme were detected in minor quantities with mol.wts. of 43 000 in the whey fraction and 90 000 in fat-globule membrane. Only the undegraded enzyme was present in the skim-milk membrane fraction. Xanthine oxidase is therefore synthesized and secreted as a protein with a monomeric mol.wt. of 150 000 and is not subjected to extensive proteolytic degradation during the storage of milk in mammary alveoli. The significance of the results is discussed in relation to the overall protein composition of the membranes of milk-fat globules and skim milk.


2020 ◽  
Vol 8 (5) ◽  
pp. 764 ◽  
Author(s):  
Antonia Terpou ◽  
Vassilios Ganatsios ◽  
Maria Kanellaki ◽  
Athanasios A. Koutinas

An alternative methodology is proposed for low temperature winemaking using freeze-dried raw materials. Pine sawdust was delignified and the received porous cellulosic material was applied as immobilization carrier of the psychrotolerant yeast strain Saccharomyces cerevisiae AXAZ-1. The immobilization of yeast cells was examined and verified by scanning electron microscopy (SEM). The immobilized biocatalyst and high-gravity grape must were separately freeze-dried without cryoprotectants and stored at room temperature (20–22 °C) for 3 months. The effect of storage on the fermentation efficiency of the immobilized biocatalyst at low temperatures (1–10 °C), as well as on the aromatic characteristics of the produced wines was evaluated. Storage time had no significant effect on the fermentation efficiency of the biocatalyst resulting in most cases in high ethanol production 13.8–14.8% v/v. The volatile fraction of the produced wines was examined using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography mass spectrometry (GC/MS). GC-MS/SPME analysis along with the organoleptic evaluation revealed in all produced wines a plethora of fresh and fruit aromatic notes. To conclude, fermentation kinetics and aromatic profile evaluation encourages the production of high-quality sweet wines at low temperatures using pine sawdust (Pinus halepensis) entrapped yeast cells as a promoter.


Author(s):  
F. H. Louchet ◽  
L. P. Kubin

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.


2018 ◽  
Vol 26 (2) ◽  
pp. 058
Author(s):  
Anna P. Roswiem ◽  
Triayu Septiani

<em>Bahan<strong> </strong>baku untuk membuat baso adalah daging hewan, pada umumnya dari daging sapi, ayam, ikan dan babi. Di beberapa daerah di Indonesia terjadi kasus baso tikus. Tujuan penelitian ini adalah menguji ada tidaknya kandungan daging tikus pada produk baso yang dijual di pasar Cempaka Putih-Kecamatan Kramat Jakarta Pusat dan di pedagang baso atau mie baso di sekitar kampus Universitas YARSI Jakarta. Daging adalah protein salah satu metode untuk mengidentifikasi protein adalah metode Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE).<strong> </strong>Hasil penelitian menunjukkan bahwa dari 6 sampel baso terindikasi ada 2 sampel baso dengan nomor 1 dan 5 yang dibuat dari campuran daging sapi dan tikus; ada 1 sampel baso dengan nomor 6 yang terbuat dari daging tikus; dan 2 sampel baso dengan nomor 2 dan 3 yang terbuat dari campuran sapi  dan babi, dan hanya 1 sampel baso dengan nomor sampel 4 yang benar-benar terbuat dari daging sapi.</em>


Alloy Digest ◽  
2008 ◽  
Vol 57 (1) ◽  

Abstract Invar is an Fe-Ni alloy with 36% Ni content that exhibits the lowest expansion of known metals from very low temperatures up to approximately 230 deg C (445 deg F). Invar M93 is a cryogenic Invar with improved weldability. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear and bend strength as well as fracture toughness and fatigue. It also includes information on low temperature performance as well as forming and joining. Filing Code: FE-143. Producer or source: Metalimphy Precision Alloys.


2018 ◽  
Vol 10 (6) ◽  
pp. 06013-1-06013-5 ◽  
Author(s):  
I. G. Vorobiova ◽  
◽  
Yu. A. Mirgorod ◽  
A. S. Chekadanov ◽  
◽  
...  

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