Penetrability of a marine pseudomonad by inulin, sucrose, and glycerol and its relation to the mechanism of lysis

1970 ◽  
Vol 16 (2) ◽  
pp. 75-81 ◽  
Author(s):  
Francis L. A. Buckmire ◽  
Robert A. MacLeod

Cells of a marine pseudomonad were prevented from lysing when suspended in a 0.15 M sucrose solution even after treatment of the sucrose with an ion exchange resin to remove contaminating trace elements. Isolated cell envelopes of the organism in concentrations of sucrose able to prevent lysis of the cells released non-dialyzable hexosamine-containing material into the suspending medium. This did not occur when the envelopes were suspended in concentrations of NaCl able to prevent cell lysis. Glycerol was found to occupy almost all the available fluid space in a packed cell preparation of the organism. Sucrose occupied less space than glycerol, and inulin the least. When the sucrose concentration was increased from 3 mM to 0.2 M, both the sucrose and inulin spaces increased. The results have been interpreted as indicating that sucrose prevents lysis by balancing the internal osmotic pressure of the cells, that the various layers of the cell envelope of the organism differ in their permeability to various solutes, and that the whole cell shrinks in solutions of high osmotic pressure.

1990 ◽  
Vol 271 (2) ◽  
pp. 305-308 ◽  
Author(s):  
N Martinet ◽  
S Beninati ◽  
T P Nigra ◽  
J E Folk

N1N8-Bis(gamma-glutamyl)spermidine was found in exhaustive proteolytic digests of isolated cell envelopes from human epidermis at levels comparable with those of epsilon-(gamma-glutamyl)lysine. Significantly higher than normal amounts of these compounds, particularly the bis(gamma-glutamyl)polyamine, were observed in envelopes from afflicted areas (scales) of psoriatic patients. These findings support the notions that N1N8-bis(gamma-glutamyl)spermidine, like epsilon-(gamma-glutamyl)lysine, functions in cell envelopes as an enzyme-generated protein cross-link and stabilizing force and that individuals with the chronic, recurrent skin disease, psoriasis, exhibit in involved epidermis abnormal cell-envelope-protein cross-linking.


1971 ◽  
Vol 24 (3) ◽  
pp. 665 ◽  
Author(s):  
Nele Findlay ◽  
ML Reed ◽  
FV Mercer

Analysis of Abutilon nectaries shows that the sugar content of the nectary rises sharply as nectar secretion begins. Nectar secretion on the plant occurs at a steady rate of 2-5 mg total sugar per flower. hour for 36-48 hr. A total of about 100 mg sugar per flower is secreted, and this is about seven times the maximum sugar content of the nectary at any time. Secretion of sugar in nectar by isolated nectaries floating on 0--0� 4M sucrose solution is in two phases. During phase I the rate is independent of concentration of sucrose in the external medium, but the rate is decreased by increasing the osmotic pressure of the medium with mannitol. In phase II the rate of secretion of sugar depends on the concentration of sucrose in the external medium and is independent of increase in osmotic pressure with mannitol. The rate is zero on water and reaches a maximum on about O� 4M sucrose. Secretion is reduced in both phases on media of sucrose concentration


1970 ◽  
Vol 118 (5) ◽  
pp. 759-763 ◽  
Author(s):  
T. Nurminen ◽  
H. Suomalainen

1. The existence of phospholipase and lipase activities in the isolated cell envelopes of baker's yeast was demonstrated. 2. The content of phospholipase was found to be markedly higher than that of lipase. 3. After partial enzymic digestion of the isolated cell envelopes, the bulk of the lipolytic activities was recovered in the sedimentable preparations, which consisted of the fragments of the plasma membrane. 4. During repeated washings, the lipase was completely released from the cell envelopes, as were also the bulk of the lipid components and most of the Mg2+-dependent adenosine triphosphatase, an enzyme connected with the plasma membrane. The phospholipase was more firmly bound to the preparation but not so firmly as the external saccharase. 5. These results indicate that the lipolytic enzymes found in the cell envelopes are mostly located in the plasma membrane.


1981 ◽  
Vol 6 ◽  
Author(s):  
Jeffrey D. Williams

ABSTRACTIncreased concern by the State of South Carolina over the condition and capacity of the low-level radioactive waste burial site at Barnwell has prompted them to promulgate new regulations on waste burial containers. As of September 30, 1981, ion exchange resin and filter media waste with an activity of 1 μCi/cc or greater and with isotopes with halflives greater than five years disposed at Barnwell shall be solidified or confined in a “high integrity container”. The materials and designs of these containers are required to provide waste isolation from the environment for a period of 300 years and provide the structural integrity specified in 49 CFR 173.398(b). HITTMAN has been active in the design and development of containers suitable for this purpose with this paper detailing the analyses involved. Material selections were limited to stainless steel, fiberglass, and polyethylenes. Structural concerns focused on overpressure requirements, drop-testing requirements, and lifting capabilities. With a lifetime dose of up to 108 rads, the possibilities of radiation damage were considered. Preliminary selection of polyethylene was based on satisfactory resolution of these issues and economic factors.


2016 ◽  
Vol 52 ◽  
pp. 171-176
Author(s):  
M. Palkina ◽  
O. Metlitska

The aim of the research – adaptation, optimization and using of existing DNA extraction methods from bees’ biological material with the reagent «Chelex-100" under complex economic conditions of native laboratories, which will optimize labour costs and improve the economic performance of DNA extraction protocol. Materials and methods. In order to conduct the research the samples of honey bees’ biological material: queen pupae exuviae, larvae of drone brood, some adult bees’ bodies (head and thorax) were selected. Bowl and drone brood were obtained from the experimental bee hives of Institute of Apiculture nd. a. P. I. Prokopovich of NAAS. DNA extraction from biosamples of Apis mellifera ssp. was carried out using «Chelex-100®» ion exchange resin in different concentrations and combinations. Before setting tests for determination of quantitative and quality indexes, dilution of DNA samples of the probed object was conducted in ratio 1:40. The degree of contamination with protein and polysaccharide fractions (OD 260/230), quantitative content of DNA (OD 260/280) in the extracted tests were conducted using spectrophotometer of «Biospec – nano» at the terms of sample volume in 2 µl and length of optical way in 0,7 mm [7]. Verification of DNA samples from biological material of bees, isolated by «Chelex-100®», was conducted after cold keeping during 24 hours at 20°C using PСR with primaries to the fragment of gene of quantitative trait locus (QTL) Sting-2 of next structure [8]:  3' – CTC GAC GAG ACG ACC AAC TTG – 5’; 3' – AAC CAG AGT ATC GCG AGT GTT AC – 5’ Program of amplification: 94 °C – 5 minutes – 1 cycle; 94 °C – 1 minute, 57°C – 1 minute, 72 °C – 2 minutes – 30 cycles; elongation after 72°C during 2 minutes – 1 cycle. The division of obtained amplicons was conducted by gel electrophoresis at a low current – 7 µÀ, in 1,5 % agarose gel (Sigma ®) in TAE buffer [7]. The results. At the time of optimization of DNA isolation methods, according to existing methods of foreign experts, it was found optimal volume of ion exchange resin solution was in the proposed concentration: instead of 60 µl of solution used 120 µl of «Chelex-100®», time of incubation was also amended from 30 minutes to 180 minutes [9]. The use of the author's combination of method «Chelex-100®» with lysis enzymes, proteinase K and detergents (1M dithiothreitol), as time of incubation was also amended, which was reduced to 180 minutes instead of the proposed 12 hours [10]. Changes in quality characteristics of obtained DNA in samples after reduction in incubation time were not found. Conclusions. The most economical method of DNA isolation from bees’ biological material is 20% solution of «Chelex-100» ion exchange resin with the duration of the incubation period of 180 minutes. It should also be noted that the best results can be obtained from exuviae, selected immediately after the queen’s exit from bowl, that reduces the likelihood of DNA molecules destruction under the influence of nucleases activation, but not later than 12 hours from release using the technology of isolated obtain of queens.


1977 ◽  
Vol 49 (6) ◽  
pp. 764-766 ◽  
Author(s):  
Toshihiko. Hanai ◽  
Harold F. Walton

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