Determination of nuclear DNA of five Eucoccidian parasites, Isospora (Toxoplasma) gondii, Sarcocystis cruzi, Eimeria tenella, E. acervulina and Plasmodium berghei, with special reference to gamontogenesis and meiosis in I. (T.) gondii

Parasitology ◽  
1984 ◽  
Vol 88 (3) ◽  
pp. 531-553 ◽  
Author(s):  
A. W. C. A. Cornelissen ◽  
J. P. Overdulve ◽  
M. Van Der Ploeg
Keyword(s):  
Mathematical Model ◽  
Toxoplasma Gondii ◽  
Plasmodium Berghei ◽  
Nuclear Dna ◽  
Eimeria Tenella ◽  
Frequency Distributions ◽  
Dna Contents ◽  
Dna Values ◽  
Sarcocystis Cruzi

SUMMARYDNA contents of individual stages of Isospora (Toxoplasma) gondii and other Eucoccida were measured after Feulgen-pararosaniline (SO2) staining either by direct microfluorometry or by scanning of microphotographic negatives. Frequency distributions were analysed using a computer program based on a mathematical model describing cell division. All stages of I. (T.) gondii, except fertilized macrogametes (2c), contained a haploid amount of DNA (1c), indicating that meiosis in I. (T.) gondii occurs during sporogony. Microgametes possessed 3·3% DNA in excess, presumably mitochondrial DNA. Nuclei of M2-and M3-merozoites differed in two characteristics: a small but distinct nucleolus was observed in almost 50% of the M2-merozoites but in none of the M3-merozoites; all M2 merozoites were strictly haploid, while all M3-merozoites were synthesizing DNA (17% above the haploid value). It may be concluded that all M2- and M3-merozoites are already sexually differentiated, i.e. are macro- and microgamontoblasts, respectively. DNA synthesis necessary for the development of the microgamont starts already in the microgamontoblast stage (M3-merozoite). M2-merozoites macrogametes, synthesize 11% extra DNA before fertilization, (after fertilization an extra amount of 12% of the diploid value was found), probably by amplification of genes for proteins which are needed for rapid maturation and later sporogony. Essentially parallel results have been found in Eimeria tenella and in crescent cystozoites of Sarcocystis cruzi. Absolute DNA values in representatives of the Eucoccida have been estimated as follows (10−15 g): I. (T.) gondii, 96; E. tenella and E. acervulina, both 75; S. cruzi, 216; Plasmodium berghei, 27. The value of the estimation of total haploid amounts as a tool in taxonomy of Eucoccida is discussed.

Cytochemical studies on nuclear DNA of four eucoccidian parasites, Isospora (Toxoplasma) gondii, Eimeria tenella, Sarcocystis cruzi and Plasmodium berghei

Parasitology ◽  
1984 ◽  
Vol 88 (1) ◽  
pp. 13-25 ◽  
Author(s):  
A. W. C. A. Cornelissen ◽  
J. P. Overdulve ◽  
M. Van Der Ploeg
Keyword(s):  
Toxoplasma Gondii ◽  
Plasmodium Berghei ◽  
Nuclear Dna ◽  
Single Cells ◽  
Fluorescence Emission ◽  
Green Light ◽  
Eimeria Tenella ◽  
Feulgen Staining ◽  
Accurate Identification ◽  
Sarcocystis Cruzi

SUMMARYFeulgen-pararosaniline(SO2) staining was performed on stages in the life-cycle of Isospora (Toxoplasma) gondii, Eimeria tenella, Sarcocystis cruzi and Plasmodium berghei. The fluorescence emission of the stained DNA in nuclei of these stages was examined and compared with absorption microscopy measurements at 560 nm (green light) of the same specimens. Accurate identification of single cells, and especially discrimination between young schizonts and young gamonts was difficult after Feulgen staining. To overcome this problem preparations were first stained with Giemsa and the cells of interest precisely located with the aid of an England finder. The same preparations were then hydrolysed and stained with Feulgen—pararosaniline(SO2), after which the previously identified cells were investigated. The DNA distribution after Feulgen staining corresponded with the shape of nuclei after Giemsa staining. DNA was present in all investigated stages of the four parasites, including macrogamonts of I. (T.) gondii and E. tenella and peripheral blood gamonts of P. berghei. Macrogamonts could be recognized, even at a stage at which they can hardly be differentiated from young schizonts in Giemsa-stained preparations, by their typical distribution pattern of Feulgen fluorescence. Feulgen fluorescence was more granular and confined to the peripheral region of the nucleus, leaving a distinct nucleolus unstained. The horseshoe-shaped nuclei typical of macrogamonts could also be observed in some second generation merozoites of E. tenella, indicating that these merozoites are already sexually differentiated. The relationship between the present cytochemical observations and the ultrastructure of the four investigated parasites is discussed.

scholarly journals Quantitation of nuclear DNA in Ascaris lumbricoides: DNA constancy and chromatin diminution

1976 ◽  
Vol 27 (2) ◽  
pp. 339-348 ◽  
Author(s):  
J. Pasternak ◽  
R. Barrell
Keyword(s):  
Ascaris Lumbricoides ◽  
Nuclear Dna ◽  
Mean Value ◽  
Terminal Portion ◽  
Chromatin Diminution ◽  
The Third ◽  
Embryonic Cleavage ◽  
Dna Contents ◽  
Dna Values ◽  
The Mean

SUMMARYThe DNA contents of nuclei during gametogenesis and embryogenesis in Ascaris lumbricoides were measured by Feulgen-microspectrophoto-metry. The variability in the mean value for the haploid amount of DNA in sperm from different males processed at different times was not significant when sperm cell samples were taken from the same region of the seminal vesicle. As the sperm mature, the extent of uptake of Feulgen dye decreases nonsystematically. A similar phenomenon occurs during embryogenesis, and as noted by others, primary oocytes in the terminal portion of the oviduct become Feulgen-negative. Feulgen-positive primary oocytes maintain a 4C DNA value without significant variation. Notwithstanding the differences in Feulgen-DNA values in certain types of nuclei, our evidence supports the view that in Ascaris lumbricoides the amount of intraspecific DNA has a constant value between individual organisms and from one generation to the next. About 34% of the DNA of the zygote is lost through chromatin diminution at the third embryonic cleavage. This quantity represents 0·23 pg DNA per haploid equivalent.

scholarly journals Variation in Ploidy Levels and Reproductive Pathways Among Flowering Crabapples

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 773B-773
Author(s):  
Thomas Ranney* ◽  
Thomas Eaker
Keyword(s):  
Ploidy Level ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Unreduced Gametes ◽  
Breeding Programs ◽  
Ploidy Levels ◽  
Level Measurement ◽  
Dna Contents

Information on ploidy levels is extremely valuable for use in plant breeding programs. Fertility, crossability, and heritability of traits are all influenced by ploidy levels. Knowledge of reproductive pathways, including occurrence of apomixes, pseudogamy, and formation of unreduced gametes can also be important information for developing breeding strategies. Although ploidy level can be determined by counting chromosomes, flow cytometry provides a reliable and much faster means for determination of nuclear DNA content and associated ploidy level. Measurement of ploidy levels of seeds (embryo and endosperm) can also provide useful insights into reproductive pathways. The objective of this study was to determine the approximate genome size, estimated ploidy level, and range of reproductive pathways of a diverse collection of flowering crapbapples (Malus spp.). Genome sizes were calculated as nuclear DNA content for unreduced tissue (2C). Results from the taxa included in our survey showed DNA contents ranging from 1.52 to 1.82 for diploids, 2.40 to 2.62 for triploids, and 3.36 to 3.74 pg/2C for tetraploids. Based on these ranges, we identified 43 diploid, 10 triploid, and 4 tetraploid crabapple taxa in this collection. Results from open pollinated seeds and seedlings demonstrated a variety of reproductive pathways including apomixes and unreduced gametes. This research provides information on ploidy levels and reproductive pathways of flowering crabapples and will allow for more systematic and efficient progress in the development of improved cultivars.

DETERMINATION OF PERFORMANCE INDICATORS OF THE TRUCK KrAZ-6510TE

2020 ◽  
pp. 19-26
Author(s):  
Olexandr Pavlenko ◽  
Serhii Dun ◽  
Maksym Skliar
Keyword(s):  
Mathematical Model ◽  
Surface Friction ◽  
Building Structures ◽  
Maximum Torque ◽  
Military Equipment ◽  
Military Vehicles ◽  
Force Magnitude ◽  
Vehicle Mobility ◽  
The Mathematical Model

In any economy there is a need for the bulky goods transportation which cannot be divided into smaller parts. Such cargoes include building structures, elements of industrial equipment, tracked or wheeled construction and agricultural machinery, heavy armored military vehicles. In any case, tractor-semitrailer should provide fast delivery of goods with minimal fuel consumption. In order to guarantee the goods delivery, tractor-semitrailers must be able to overcome the existing roads broken grade and be capable to tow a semi-trailer in off-road conditions. These properties are especially important for military equipment transportation. The important factor that determines a tractor-semitrailer mobility is its gradeability. The purpose of this work is to improve a tractor-semitrailer mobility with tractor units manufactured at PJSC “AutoKrAZ” by increasing the tractor-semitrailer gradeability. The customer requirements for a new tractor are determined by the maximizing the grade to 18°. The analysis of the characteristics of modern tractor-semitrailers for heavy haulage has shown that the highest rate of this grade is 16.7°. The factors determining the limiting gradeability value were analyzed, based on the tractor-semitrailer with a KrAZ-6510TE tractor and a semi-trailer with a full weight of 80 t. It has been developed a mathematical model to investigate the tractor and semi-trailer axles vertical reactions distribution on the tractor-semitrailer friction performances. The mathematical model has allowed to calculate the gradeability value that the tractor-semitrailer can overcome in case of wheels and road surface friction value and the tractive force magnitude from the engine. The mathematical model adequacy was confirmed by comparing the calculations results with the data of factory tests. The analysis showed that on a dry road the KrAZ-6510TE tractor with a 80 t gross weight semitrailer is capable to climb a gradient of 14,35 ° with its coupling mass full use condition. The engine's maximum torque allows the tractor-semitrailer to overcome a gradient of 10.45° It has been determined the ways to improve the design of the KrAZ-6510TE tractor to increase its gradeability. Keywords: tractor, tractor-semitrailer vehicle mobility, tractor-semitrailer vehicle gradeability.

Research on a Generating Method of Spiral Flutes of Hourglass Worm Gear Hob

2017 ◽  
Author(s):  
Yang Jie ◽  
Li Haitao ◽  
Rui Chengjie ◽  
Wei Wenjun ◽  
Dong Xuezhu
Keyword(s):  
Mathematical Model ◽  
Manufacturing System ◽  
Worm Gear ◽  
Virtual Manufacturing ◽  
Transmission Ratio ◽  
Method Of Determination ◽  
Generating Method ◽  
Multiple Threads ◽  
Different Shapes

All of the cutting edges on an hourglass worm gear hob have different shapes and spiral angles. If the spiral angles are small, straight flutes are usually adopted. But for the hob with multiple threads, the absolute values of the negative rake angles at one side of the cutting teeth will greatly affect the cutting performance of the hob if straight flutes are still used. Therefore, spiral flutes are usually adopted to solve the problem. However, no method of determination of the spiral flute of the hourglass worm gear hob has been put forward till now. Based on the curved surface generating theory and the hourglass worm forming principle, a generating method for the spiral flute of the planar double enveloping worm gear hob is put forward in this paper. A mathematical model is built to generate the spiral flute. The rake angles of all cutting teeth of the hob are calculated. The laws of the rake angles of the cutting teeth of four hobs with different threads from one to four threads are analyzed when straight flutes and spiral flutes are adopted respectively. The laws between the value of the negative rake angles of the hob with four threads and the milling transmission ratio are studied. The most appropriate milling transmission ratio for generating the spiral flute is obtained. The machining of the spiral flutes is simulated by a virtual manufacturing system and the results verify the correctness of the method.

Methodology of Estimation of Fire Separation Distances between Construction Facilities by Calculation

2020 ◽  
Vol 1006 ◽  
pp. 93-100
Author(s):  
Vadym Nizhnyk ◽  
Yurii Feshchuk ◽  
Volodymyr Borovykov
Keyword(s):  
Mathematical Model ◽  
Heat Flux ◽  
Linear Regression ◽  
Ignition Temperature ◽  
Oil Products ◽  
Regression Equations ◽  
Fire Load ◽  
Literary Sources ◽  
Tabular Method

Based on analysis of appropriate literary sources we established that estimation of fire separation distances was based of two criteria: heat flux and temperature. We proposed to use “ignition temperature of materials” as principal criterion when determining fire separation distances between adjacent construction facilities. Based on the results derived while performing complete factorial we created mathematical model to describe trend of changing fire separation distances depending on caloric power of fire load (Q), openings factor of the external enclosing structures (k) and duration of irradiation (t); moreover, its adequacy was confirmed. Based on linear regression equations we substantiated calculation and tabular method for the determination of fire separation distances for a facility being irradiated which contains combustible or otherwise non-combustible façade and a facility where liquid oil products turn. We developed and proposed general methodology for estimation of fire separation distances between construction facilities by calculation.

scholarly journals Study on Optimal Placement and Reasonable Number of Viscoelastic Dampers by Improved Weight Coefficient Method

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Ji-ting Qu ◽  
Hong-nan Li
Keyword(s):  
Mathematical Model ◽  
Weight Coefficient ◽  
Optimal Placement ◽  
Optimal Method ◽  
Analogy Method ◽  
Numerical Examples ◽  
Viscoelastic Dampers ◽  
Reasonable Number ◽  
Coefficient Method

A new optimal method is presented by combining the weight coefficient with the theory of force analogy method. Firstly, a new mathematical model of location index is proposed, which deals with the determination of a reasonable number of dampers according to values of the location index. Secondly, the optimal locations of dampers are given. It can be specific from stories to spans. Numerical examples are illustrated to verify the effectiveness and feasibility of the proposed mathematical model and optimal method. At last, several significant conclusions are given based on numerical results.

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