Preparation of cell populations with stabilized erythropoietic potential from the primitive streak chick blastodisc: Some implications for control of gastrulation

1978 ◽  
Vol 56 (6) ◽  
pp. 430-439 ◽  
Author(s):  
S. D. Wainwright ◽  
Lillian K. Wainwright
Keyword(s):  
Egg Yolk ◽  
Primitive Streak ◽  
Cell Suspensions ◽  
Erythroid Cells ◽  
High Concentration ◽  
Differentiated Cells ◽  
Viable Cells ◽  
Large Numbers ◽  
Cell Dispersion ◽  
Improved Methods

Improved methods for preparation from primitive streak chick blastodiscs of cell suspensions capable of forming erythroid cells in culture have been developed. When blastodiscs were preincubated with hyaluronidase in the absence of collagenase before cell dispersion and a high concentration of methyl-α-mannoside was present in all media, the yields of cells were some 10-fold higher than those obtained by former procedures. Cell suspensions obtained consisted almost entirely of viable cells, yielded large numbers of free mature erythrocytes in liquid culture, and formed erythroid colonies and bursts in solidified medium. The capacity to form differentiated cells after re sedimentation through Ficoll density gradients was partly stabilized.Addition of egg yolk homogenate to the blastodiscs immediately following treatment with hyaluronidase and to all media used thereafter largely stabilized the capacity to form erythroid cells during re sedimentation through Ficoll density gradients.Possible relevance of observations made during development of the procedures to the control of onset of cell migration in the process of gastrulation is indicated.

Use of Iron Milk Medium for Enumeration of Clostridium perfringens

1982 ◽  
Vol 65 (5) ◽  
pp. 1129-1133 ◽  
Author(s):  
William D St John ◽  
Jack R Matches ◽  
Marleen M Wekell
Keyword(s):  
Clostridium Perfringens ◽  
Incubation Time ◽  
Incubation Temperature ◽  
Egg Yolk ◽  
Most Probable Number ◽  
Biochemical Tests ◽  
Probable Number ◽  
Large Numbers ◽  
Whole Milk ◽  
Short Incubation Time

Abstract A simple iron milk medium was used for isolation and enumeration of Clostridium perfringens from soil, sludge, and water samples. The whole milk contained only iron powder as a reducing agent; no other inhibitors were added. The iron milk most probable number (MPN) procedure was compared with 4 plating media: sulfite-polymyxin-sulfadiazine, Shahidi-Ferguson perfringens, tryptose-sulfite- cycloserine (both with and without egg yolk), and tryptone-sulfite-neomycin. The selectivity of the iron milk relies solely on the rapid growth of C. perfringens at 45°C and the stormy fermentation reaction within 18 h. Isolates were confirmed as C. perfringens by standard biochemical tests. The iron milk MPN procedure compared very well with the 4 plating media tested. Selectivity of incubation temperature, short incubation time, and ease of identification by the characteristic stormy fermentation make this method ideal for enumerating C. perfringens from large numbers of samples.

GATA-1 Regulates Growth and Differentiation of Definitive Erythroid Lineage Cells During In Vitro ES Cell Differentiation

Blood ◽  
1998 ◽  
Vol 92 (11) ◽  
pp. 4108-4118 ◽  
Author(s):  
Naruyoshi Suwabe ◽  
Satoru Takahashi ◽  
Toru Nakano ◽  
Masayuki Yamamoto
Keyword(s):  
Es Cells ◽  
Embryonic Stem ◽  
Erythroid Cells ◽  
Es Cell ◽  
Globin Mrna ◽  
Differentiated Cells ◽  
Vitro Analysis ◽  
Definitive Hematopoiesis

Abstract Although the importance of GATA-1 in both primitive and definitive hematopoietic lineages has been shown in vivo, the precise roles played by GATA-1 during definitive hematopoiesis have not yet been clarified. In vitro differentiation of embryonic stem (ES) cells using OP9 stroma cells can generate primitive and definitive hematopoietic cells separately, and we have introduced a method that separates hematopoietic progenitors and differentiated cells produced in this system. Closer examination showed that the expression of erythroid transcription factors in this system is regulated in a differentiation stage-specific manner. Therefore, we examined differentiation of GATA-1 promoter-disrupted (GATA-1.05) ES cells using this system. Because the GATA-1.05 mice die by 12.5 embryonic days due to the lack of primitive hematopoiesis, the in vitro analysis is an important approach to elucidate the roles of GATA-1 in definitive hematopoiesis. Consistent with the in vivo observation, differentiation of GATA-1.05 mutant ES cells along both primitive and definitive lineages was arrested in this ES cell culture system. Although the maturation-arrested primitive lineage cells did not express detectable amounts of ɛy-globin mRNA, the blastlike cells accumulated in the definitive stage showed β-globin mRNA expression at approximately 70% of the wild type. Importantly, the TER119 antigen was expressed and porphyrin was accumulated in the definitive cells, although the levels of both were reduced to approximately 10%, indicating that maturation of definitive erythroid cells is arrested by the lack of GATA-1 with different timing from that of the primitive erythroid cells. We also found that the hematopoietic progenitor fraction of GATA-1.05 cells contains more colony-forming activity, termed CFU-OP9. These results suggest that theGATA-1.05 mutation resulted in proliferation of proerythroblasts in the definitive lineage.

scholarly journals CELLULAR DIFFERENTIATION OF THE IMMUNE SYSTEM OF MICE

1969 ◽  
Vol 129 (1) ◽  
pp. 185-199 ◽  
Author(s):  
G. M. Shearer ◽  
G. Cudkowicz ◽  
R. L. Priore
Keyword(s):  
Immune System ◽  
Specific Antibody ◽  
Cellular Differentiation ◽  
Single Cells ◽  
Donor Cell ◽  
Cell Suspensions ◽  
The Other ◽  
Spleen Cells ◽  
Igg Antibody ◽  
Differentiated Cells

Spleen cell suspensions of primed donor mice containing precursors of immunocytes have been transplanted into X-irradiated recipient mice 122–138 days after immunization. Following secondary stimulation with antigen (sheep erythrocytes), these precursors, called antigen-sensitive units (ASU), gave rise to progeny cells secreting specific antibody in the spleens of recipients. Single cells releasing IgM hemolysins (direct plaque-forming cells or PFC), IgG hemolysins (indirect PFC), and hemagglutinins (cluster-forming cells or CFC) were enumerated. By transplanting graded and limiting numbers of primed spleen cells, inocula were found which contained one or a few ASU reaching the recipient spleens. We estimated, thereby, the frequency of ASU detectable by our procedures in donor cell suspensions. The values obtained from direct and in-indirect plaque assays, and from cluster assays were 1 in ∼8.0 x 105, 1 in ∼4.4 x 105, and 1 in ∼5.9 x 105 nucleated spleen cells, respectively. The number of splenic ASU for direct PFC was not greater than that of unimmunized mice; however, immunization greatly increased the number of splenic ASU for indirect PFC and for CFC. By applying to each recipient spleen direct and indirect plaque tests and cluster tests, we found that positivity for each type of immunocyte was independent from that of the other two types. These results confirm the unipotent nature of splenic ASU in general, and document the commitment of ASU primed with SRBC to generate progeny cells secreting antibody of a single molecular (IgM or IgG) or functional (lysin or agglutinin) class. We concluded that splenic ASU are composed of relatively differentiated cells of the immune system of mice. With respect to specificity and class differentiation, ASU appear to be as specialized as antibody-producing cells themselves. Our results did not support the view that ASU-derived clonal populations shift from IgM to IgG antibody production.

scholarly journals Purification of erythroblastic nests

Blood ◽  
1981 ◽  
Vol 57 (5) ◽  
pp. 922-927
Author(s):  
AJ Macario ◽  
C Dugan ◽  
IL Perez-Lloret ◽  
E Conway de Macario
Keyword(s):  
Spleen Cell ◽  
Trypan Blue ◽  
Single Cells ◽  
Cell Suspensions ◽  
Differential Centrifugation ◽  
Minimum Essential Medium ◽  
Trypan Blue Exclusion ◽  
Large Numbers ◽  
Very High

We describe a method for preparing purified erythroblastic nests in large numbers (approximately 10(6)/run) in three steps: (1) induction of splenic erythropoiesis in mice, (2) preparative differential centrifugation for the removal of erythrocytes and single cells from spleen cell suspensions, and (3) sedimentation in an isokinetic gradient of Ficoll 400 in Joklik's modification of minimum essential medium. Viability of isolated EN is very high, as demonstrated by the trypan blue exclusion and in vitro erythrocyte formation methods.

scholarly journals Improved Pigmentation of Egg Yolk by Feeding of Yeast Phaffia rhodozyma Containing High Concentration of Astaxanthin in Laying Hens.

2000 ◽  
Vol 37 (3) ◽  
pp. 162-170 ◽  
Author(s):  
Yukio AKIBA ◽  
Kan SATO ◽  
Kazuaki TAKAHASHI ◽  
Masaaki TOYOMIZU ◽  
Yoko TAKAHASHI ◽  
...  
Keyword(s):  
Laying Hens ◽  
Egg Yolk ◽  
Phaffia Rhodozyma ◽  
High Concentration

Sensitivity of Campylobacter jejuni to Drying

1982 ◽  
Vol 45 (6) ◽  
pp. 507-510 ◽  
Author(s):  
MICHAEL P. DOYLE ◽  
DEBRA J. ROMAN
Keyword(s):  
Campylobacter Jejuni ◽  
Room Temperature ◽  
Skim Milk ◽  
Initial Population ◽  
Log10 Reduction ◽  
Viable Cells ◽  
Large Numbers ◽  
Thermophilic Campylobacter ◽  
And Storage ◽  
Intermediate Rate

Several factors were shown to influence the rate of inactivation of Campylobacter sp. when dried on a glass surface. These included strain, temperature and humidity, and medium used to suspend the organism. Of the strains evaluated, all of three isolates of Campylobacter jejuni exhibited greater tolerance to drying than did a strain of nalidixic acid resistant, thermophilic Campylobacter. Inconsistent results were obtained when organisms were dried and maintained at 25 C. Viable cells from two of four strains having an initial population of >107 were not recovered after 24 h in an anhydrous environment at 25 C. Under comparable conditions, drying C. jejuni FRI-CF8 in the presence of skim milk at 25 C resulted in a >107 log10 reduction of cells within 1 day in one instance; a 5 log10 decline after 7 days in another; and inactivation at an intermediate rate on a third occasion. Rates of death were greatly reduced when cells were dried and held at 4 C. At this temperature and in the presence of skim milk and an anhydrous environment, a 5 log10 reduction of CF8 occurred after 6 weeks. In all instances, greater survival occurred when organisms were dried in the presence of Brucella broth than in skim milk. When held in environments of different relative humidities (RH), survival was greatest in the presence of 14% or less RH. Results suggest that C. jejuni is generally quite sensitive to drying and storage at room temperature, but, at refrigeration temperature and the appropriate humidity, large numbers may survive drying and remain viable for several weeks.

scholarly journals Purification of erythroblastic nests

Blood ◽  
1981 ◽  
Vol 57 (5) ◽  
pp. 922-927 ◽  
Author(s):  
AJ Macario ◽  
C Dugan ◽  
IL Perez-Lloret ◽  
E Conway de Macario
Keyword(s):  
Spleen Cell ◽  
Trypan Blue ◽  
Single Cells ◽  
Cell Suspensions ◽  
Differential Centrifugation ◽  
Minimum Essential Medium ◽  
Trypan Blue Exclusion ◽  
Large Numbers ◽  
Very High

Abstract We describe a method for preparing purified erythroblastic nests in large numbers (approximately 10(6)/run) in three steps: (1) induction of splenic erythropoiesis in mice, (2) preparative differential centrifugation for the removal of erythrocytes and single cells from spleen cell suspensions, and (3) sedimentation in an isokinetic gradient of Ficoll 400 in Joklik's modification of minimum essential medium. Viability of isolated EN is very high, as demonstrated by the trypan blue exclusion and in vitro erythrocyte formation methods.

GATA-1 Regulates Growth and Differentiation of Definitive Erythroid Lineage Cells During In Vitro ES Cell Differentiation

Blood ◽  
1998 ◽  
Vol 92 (11) ◽  
pp. 4108-4118 ◽  
Author(s):  
Naruyoshi Suwabe ◽  
Satoru Takahashi ◽  
Toru Nakano ◽  
Masayuki Yamamoto
Keyword(s):  
Es Cells ◽  
Embryonic Stem ◽  
Erythroid Cells ◽  
Es Cell ◽  
Globin Mrna ◽  
Differentiated Cells ◽  
Vitro Analysis ◽  
Definitive Hematopoiesis

Although the importance of GATA-1 in both primitive and definitive hematopoietic lineages has been shown in vivo, the precise roles played by GATA-1 during definitive hematopoiesis have not yet been clarified. In vitro differentiation of embryonic stem (ES) cells using OP9 stroma cells can generate primitive and definitive hematopoietic cells separately, and we have introduced a method that separates hematopoietic progenitors and differentiated cells produced in this system. Closer examination showed that the expression of erythroid transcription factors in this system is regulated in a differentiation stage-specific manner. Therefore, we examined differentiation of GATA-1 promoter-disrupted (GATA-1.05) ES cells using this system. Because the GATA-1.05 mice die by 12.5 embryonic days due to the lack of primitive hematopoiesis, the in vitro analysis is an important approach to elucidate the roles of GATA-1 in definitive hematopoiesis. Consistent with the in vivo observation, differentiation of GATA-1.05 mutant ES cells along both primitive and definitive lineages was arrested in this ES cell culture system. Although the maturation-arrested primitive lineage cells did not express detectable amounts of ɛy-globin mRNA, the blastlike cells accumulated in the definitive stage showed β-globin mRNA expression at approximately 70% of the wild type. Importantly, the TER119 antigen was expressed and porphyrin was accumulated in the definitive cells, although the levels of both were reduced to approximately 10%, indicating that maturation of definitive erythroid cells is arrested by the lack of GATA-1 with different timing from that of the primitive erythroid cells. We also found that the hematopoietic progenitor fraction of GATA-1.05 cells contains more colony-forming activity, termed CFU-OP9. These results suggest that theGATA-1.05 mutation resulted in proliferation of proerythroblasts in the definitive lineage.

GROWTH AND SURVIVAL OF BACTERIA IN PEAT: I. POWDERED PEAT AND RELATED PRODUCTS

1947 ◽  
Vol 25c (1) ◽  
pp. 1-13 ◽  
Author(s):  
A. G. Lochhead ◽  
R. H. Thexton
Keyword(s):  
Initial Increase ◽  
Subsequent Removal ◽  
High Increase ◽  
Growth And Survival ◽  
Viable Cells ◽  
Large Numbers ◽  
Neutralizing Agent ◽  
Higher Temperature ◽  
Very High ◽  
Better Than

Comparative tests of various powdered materials showed that well humified peat was superior to other preparations in maintaining the test bacteria in viable condition. Under the test conditions, sterilization of peat improved it as a medium for the maintenance of high numbers of viable cells. Neutralization was important, and more satisfactory following, than preceding, sterilization. Potassium carbonate was more suitable than sodium carbonate as neutralizing agent for promoting longevity of bacteria. Though peat allowed to dry immediately after inoculation did not permit the same high increase in bacterial numbers observed in peat kept at suitable moisture content, it was able to maintain large numbers of organisms in viable condition. Peat allowed to dry following the initial rise continued to support an increased load of living cells. After the initial increase at growth temperatures, peat stored at 4 °C. maintained numbers of bacteria better than at the higher temperature. Though immediate storage at 4 °C. resulted in a pronounced decline in numbers, subsequent removal to a temperature suitable for growth, even though delayed for as long as 12 wk., was followed by a rapid increase of bacteria to very high numbers.

Helicopter Airframe Fatigue Spectra Truncation and Verification

2014 ◽  
Vol 891-892 ◽  
pp. 714-719 ◽  
Author(s):  
John Vine ◽  
Luther Krake ◽  
Beau Krieg
Keyword(s):  
Fatigue Damage ◽  
Fatigue Cracking ◽  
Rotor Blades ◽  
Test Duration ◽  
Large Numbers ◽  
The Us ◽  
Naval Air Systems Command ◽  
Truncation Techniques ◽  
Research And Design ◽  
Improved Methods

Helicopter airframe fatigue cracking is a cause of significant and growing cost of ownership and operational readiness concerns for the operators of (primarily) metallic airframe helicopters. Airframe fatigue has often had relatively low priority for helicopters, with research and design concentrated on the fatigue of flight critical rotating structural components such as rotor blades and pitch links. The Australian Defence Science and Technology Organisation (DSTO) and Naval Air Systems Command (NAVAIR) of the US Navy are collaborating to develop improved methods and technologies that can be used to assess the fatigue damage accrued by ageing helicopter airframes. The flight load sequences, or fatigue spectra, experienced by a helicopter airframe in its lifetime contain many billions of load cycles due to rotor revolutions. The application of spectra containing such vast numbers of load cycles is often impractical for reasons of test duration and cost, therefore spectra simplification techniques must be employed. To this end, truncation is a technique that is used to eliminate non-or lesser-damaging load cycles, producing spectra equivalent in terms of theoretical fatigue damage but with substantially fewer load cycles. This paper describes several truncation techniques that have recently been developed at DSTO specifically to deal with the very large numbers of load cycles that are characteristic of helicopter airframe fatigue spectra. These techniques, which include both sequence and frequency based approaches, feature tunable levels of truncation and allow for large reductions in numbers of turning points while maintaining high-fidelity and realistic fatigue spectra. Also detailed are preliminary results from a comprehensive coupon test program, which DSTO is using to experimentally verify that truncated and un-truncated spectra are approximately equivalent in terms of the fatigue damage that they produce.

Sign in / Sign up

Export Citation Format

Share Document