scholarly journals Schedule of Spermatogenesis in the Pulmonate Snail Helix aspersa, with Special Reference to Histone Transition

1960 ◽  
Vol 7 (3) ◽  
pp. 515-531 ◽  
Author(s):  
David P. Bloch ◽  
Howard Y. C. Hew
Keyword(s):  
Dna Synthesis ◽  
Thymidine Incorporation ◽  
Chromosome Duplication ◽  
Staining Methods ◽  
Histone Synthesis ◽  
Pass Through ◽  
The Times ◽  
Snail Helix Aspersa ◽  
New Protein

The schedule of spermatogenesis is determined from the times necessary for cells labeled with tritium thymidine during premeiotic DNA synthesis to pass through the successive spermatogenic stages. A transition from a typically somatic histone rich in lysine, to a histone rich in arginine is shown to occur during spermatid stages. A later shift to a protamine is observed in the maturing sperm. These changes are characterized by the use of in situ staining methods. The transition to an arginine-rich histone is accompanied by incorporation of tritium-labeled arginine, hence reflects synthesis of new protein. Comparison of the timing of arginine and thymidine incorporation, and independent measurements of DNA, show that in contrast to the case of premitotic chromosome duplication, the histone synthesis in the spermatid is unaccompanied by DNA synthesis. During the initial histone change, fine filaments are formed within the nucleus, which aggregate to form lamellae. This fine structure is lost during maturation of the sperm.

scholarly journals THE SYNTHESES OF DEOXYRIBONUCLEIC ACID AND HISTONE IN THE ONION ROOT MERISTEM

1967 ◽  
Vol 33 (3) ◽  
pp. 451-467 ◽  
Author(s):  
David P. Bloch ◽  
Robert A. MacQuigg ◽  
Sheilah D. Brack ◽  
Jung-Rung Wu
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Root Meristem ◽  
The Other ◽  
Chromosomal Protein ◽  
Chromosomal Proteins ◽  
Onion Root ◽  
Histone Synthesis ◽  
The Times

A comparison of the times necessary to incorporate tritium-labeled lysine and arginine into histones and tritium-labeled thymidine into DNA indicates that the periods of DNA and histone synthesis prior to division closely coincide. (The comparison was made by determining the times necessary, after pulse labeling, for cells with marked chromosomes to enter and then leave the division stages.) An additional period of chromosomal protein synthesis, of short duration, occurs late in interphase. Most of the chromosomal proteins appear either to be synthesized in the nucleus or to migrate there shortly after synthesis. Much of this protein is conserved from one division to the next. Studies of the effects of puromycin and fluorodeoxyuridine on the syntheses of DNA and histone suggest that continuation of DNA synthesis is dependent on a concurrent protein synthesis. Histone synthesis, on the other hand, can proceed at a normal rate under conditions in which DNA synthesis is inhibited.

Analysis of movement of persons with disabilities during evacuation by lift

2020 ◽  
Vol 15 (1) ◽  
pp. 209-220
Author(s):  
Martin Szénay ◽  
Martin Lopušniak
Keyword(s):  
Computational Models ◽  
Persons With Disabilities ◽  
Entire Process ◽  
Injured Person ◽  
Impaired People ◽  
Movement Parameters ◽  
The Times ◽  
Mobility Impaired

Abstract Lifts are indispensable for the evacuation of mobility-impaired people from buildings in case of emergency. It is necessary to quantify the movement parameters of these people and describe the entire process using a suitable algorithm. The aim of the research was to quantify the times and speeds of movement for a person using a wheelchair and for an injured person. An experiment in situ was used. During the experiment, arrivals at the lift, cabin entries, and exits were monitored. The results include the times and speeds of a mobility-impaired person's movement. The experiments showed that a person using a wheelchair was slower than an injured person. The results can be used to expand computational models to account for the possibility of using lifts for evacuation.

Estudio del proceso de lavado de contenedores para eliminar tiempos y movimientos innecesarios, caso: Wash Containers S.A de C.V.

2020 ◽  
pp. 25-36
Author(s):  
Juan Alfredo Lino-Gamiño ◽  
Carlos Méndez-González ◽  
Eduardo José Salazar-Araujo ◽  
Pablo Adrián Magaña-Sánchez
Keyword(s):  
Business Process ◽  
Value Chain ◽  
Process Management ◽  
Core Business ◽  
The Core ◽  
Washing Process ◽  
Overall Performance ◽  
The Times

In the value chain it is important to keep in mind the core business of the company, since it depends largely on the competitiveness of the company and its overall performance, bearing in mind that all business indicators depend on it. In this work we will study the washing process within the company WASH CONTAINERS SA DE CV, to improve the washing processes and in this way reduce times and movements in the process leading the company to reduce costs considerably within the operations company daily, having a more competitive operation and with greater profit margin in its business process. Goals: It Improve the logistics of the movement of containers for washing and with it the core business of the company. Methodology: The action research will be applied applying Business Process Management for the improvement of processes in situ, it will be developed in a certain period of time and with that it will establish an improvement projection. Contribution: The improvement of the times for the disposal of the containers and their subsequent use, allows a better competitiveness and with it the income of the company, on the other hand, the transport companies improve in performance in quantity, quality of disposition and with it their income.

A STUDY OF BLASTOCYSTS DURING DELAY AND SUBSEQUENT IMPLANTATION IN LACTATING MICE

1968 ◽  
Vol 42 (3) ◽  
pp. 453-463 ◽  
Author(s):  
ANNE McLAREN
Keyword(s):  
Dna Synthesis ◽  
Thymidine Incorporation ◽  
Tritiated Thymidine ◽  
Uterine Horn ◽  
Uterine Epithelium ◽  
Serial Sections ◽  
Uterine Lumen ◽  
Fresh State

SUMMARY Blastocysts were studied on the 5th and 8th day of pregnancy in lactating mice, in the fresh state, flushed from the uterus, in squash preparations and in serial sections. At the earlier period some mitosis was observed. Tritiated thymidine incorporation studies gave some evidence of DNA synthesis on the 5th and 6th days of pregnancy. By the 8th day the blastocysts were longer, contained more cells, and mitosis had ceased. They were located at the anti-mesometrial end of the uterine lumen, closely apposed to the uterine epithelium, and with their long axes parallel to the long axis of the uterine horn. Implantation could be induced, either by the removal of the litter, or by the injection of an appropriate dose of oestrogen on the 5th or 7th (but not the 4th) day of pregnancy. Both treatments were followed by the appearance of W-bodies in the neighbourhood of the blastocysts, the disappearance of the shed zonae, and the appearance of Pontamine Blue reactivity, oedema of the uterine stroma and formation of the primary decidual zone, in that order.

Chemical characteristics and in situ ruminal parameters of barley for cattle: Comparison of the malting cultivar AC Metcalfe and five feed cultivars

2008 ◽  
Vol 88 (4) ◽  
pp. 711-719 ◽  
Author(s):  
Kenton J Hart ◽  
Brian G Rossnagel ◽  
Peiqiang Yu
Keyword(s):  
Nutritive Value ◽  
Degradation Kinetics ◽  
Starch Degradation ◽  
Barley Cultivars ◽  
Degradation Rates ◽  
Key Words Barley ◽  
In Situ Degradation ◽  
The Mean ◽  
Pass Through

The objective of this study was to compare the most widely grown barley cultivar in Canada, AC Metcalfe, a malting type barley, with five feed cultivars. Barley cultivars were grown at one location during 3 consecutive years and barley samples were milled to pass through a 1-mm screen and analysed to determine nutritive value. Additional samples were passed through a roller mill with a gap set at 1.12 mm and incubated ruminally for 0, 2, 4, 8, 12, 24, and 48 h in 3 dry Holstein cows fitted with rumen cannulae. The rate and extent of rumen digestion were estimated. AC Metcalfe had a higher (P < 0.001) concentration of NDF, and lower (P < 0.05) concentrations of non structural carbohydrates, starch, ADF, total digestible nutrients, and fermentable cell wall carbohydrates compared with the mean of the feed cultivars. The malting cultivar had a higher (P < 0.001) soluble DM fraction, lower (P < 0.05) CP and starch degradation rates, and a lower (P < 0.001) ruminally degradable starch concentration compared with the mean of the five feed cultivars. The results demonstrate that there are only small differences in terms of chemical composition and in situ degradation kinetics between the malting cultivar AC Metcalfe and the five feed cultivars of barley reported here. Key words: Barley, energy, protein, ruminants

The development of the tectum in Xenopus laevis: an autoradiographic study

Development ◽  
1972 ◽  
Vol 28 (1) ◽  
pp. 87-115
Author(s):  
K. Straznicky ◽  
R. M. Gaze
Keyword(s):  
Xenopus Laevis ◽  
Dna Synthesis ◽  
Optic Tectum ◽  
Tritiated Thymidine ◽  
Dorsal Surface ◽  
Autoradiographic Study ◽  
Cell Type ◽  
Pole Cells ◽  
Serial Addition ◽  
The Times

The development of the optic tectum in Xenopus laevis has been studied by the use of autoradiography with tritiated thymidine. The first part of the adult tectum to form is the rostroventral pole; cells in this position undergo their final DNA synthesis between stages 35 and 45 or shortly thereafter. Next, the cells comprising the ventrolateral border of the tectum form. These cells undergo their final DNA synthesis at or shortly after stage 45. Finally the cells comprising the dorsal surface of the adult tectum form, mainly between stages 50–55. This part of the tectum originates from the serial addition of strips of cells medially, which displace the pre-existing tissue laterally and rostrally. The formation of the tectum is virtually complete by stage 58. The tectum in Xenopus thus forms in topographical order from rostroventral to caudo-medial. The distribution of labelled cells, several stages after the time of injection of isotope, indicates that, at any one time, a segment of tectum is forming which runs normal to the tectal surface and includes all layers from the ventricular layer out to the surface. In Xenopus, therefore, the times of origin of tectal cells appear to be related not to cell type or tectal layer but to the topographical position of the cells across the surface of the tectum.

scholarly journals Autoradiographic studies of DNA and histone synthesis in successive differentiation stages of pollen grain in Hyacinthus orientalis L.

2014 ◽  
Vol 50 (3) ◽  
pp. 367-380 ◽  
Author(s):  
Elżbieta Bednarska
Keyword(s):  
Dna Replication ◽  
Dna Synthesis ◽  
Vegetative Cell ◽  
Developmental Stages ◽  
Generative Cell ◽  
Pollen Grain ◽  
Cell Nuclei ◽  
Hyacinthus Orientalis ◽  
Histone Synthesis ◽  
Generative Cells

DNA and histone synthesis in five consecutive morphological stages of <em>Hyacinthus orientalis</em> L. pollen grain differentiation were studied autoradiographically. DNA synthesis was found to occur in both the generative and the vegetative cell. DNA replication in the generative cell took place when the generative cell was still adhered to the pollen grain wall but already devoid of callose wall. DNA synthesis in the generative cell slightly preceded that in the vegetative cell. Histones were synthesized in phase S of the generative and vegetative cell. In the generative cell histone synthesis also continued at a lower level after completion of DNA replication. In the developmental stages under study the nuclei of the generative cells were decidedly richer in lysine histones than vegetative cell nuclei.

Interferon inhibition of DNA synthesis and cell division

1972 ◽  
Vol 18 (2) ◽  
pp. 145-151 ◽  
Author(s):  
M. V. O'Shaughnessy ◽  
S. H. S. Lee ◽  
K. R. Rozee
Keyword(s):  
Cell Division ◽  
Antiviral Activity ◽  
Dna Synthesis ◽  
S Phase ◽  
Cell Suspensions ◽  
Depression Effect ◽  
Growth Depression ◽  
Synchronized Cells ◽  
Inhibition Of Dna Synthesis ◽  
New Protein

Using monodispersed cell suspensions, interferon preparations were shown to have both a lethal and a growth-depression effect in the same concentration range as that required for antiviral activity. In addition, synchronized cells treated with interferon respond by delaying their normal uptake of thymidine during S phase until after a period during which new protein is synthesized. Puromycin added during this period prevents both the synthesis of this protein and the subsequent synthesis of DNA.

Effect of inhibition of DNA synthesis on histone synthesis and deposition

Biochemistry ◽  
1978 ◽  
Vol 17 (23) ◽  
pp. 4885-4893 ◽  
Author(s):  
Paul Nadeau ◽  
Denis R. Oliver ◽  
Roger Chalkley
Keyword(s):  
Dna Synthesis ◽  
Histone Synthesis ◽  
Inhibition Of Dna Synthesis

HYPERTROPHY AND HYPERPLASIA IN THE MOUSE UTERUS AFTER OESTROGEN TREATMENT: AN AUTORADIOGRAPHIC STUDY

1973 ◽  
Vol 56 (1) ◽  
pp. 133-NP ◽  
Author(s):  
L. MARTIN ◽  
C. A. FINN ◽  
GAIL TRINDER
Keyword(s):  
Cell Death ◽  
Dna Synthesis ◽  
Proliferative Response ◽  
Autoradiographic Study ◽  
Luminal Epithelium ◽  
Uterine Tissue ◽  
Mouse Uterus ◽  
Oestrogen Treatment ◽  
Ovariectomized Mice

SUMMARY The uteri of untreated ovariectomized mice consisted almost entirely of myometrium and connective tissue stroma. After oestrogenic stimulation these tissues underwent marked hypertrophy, but showed little proliferation. The luminal epithelium underwent marked hyperplasia, with most cells dividing twice to quadruple cell numbers by 35–40 h, when they made up 10–12% of the uterine tissue volume and 20% of the total uterine cell population. The proliferative response was rapid, highly synchronized and short-lived. The number of cells incorporating [3H]thymidine first increased 8·5 h after oestradiol-17β and by 13–16 h 60–70% were engaged in DNA synthesis. Up to 21 h cell-death was minimal. From 21 h onwards the proliferation rate declined and the rate of cell death increased. A second injection of oestrogen prevented the rise in death rate and produced a second smaller burst of DNA synthesis. Cells in DNA synthesis or mitosis were insensitive to oestrogen. A smaller proliferative response occurred in the glands: only 25% of cells entered DNA synthesis after the first injection of oestradiol and none after the second. Gland cells appeared to die in situ and there was no evidence that they migrated into the luminal epithelium.

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