Memoirs: The Early Embryonic Development of Rhodnius Prolixus (Hemiptera, Heteroptera)

1. Eggs of Rhodnius prolixus were incubated at constant temperature and humidity (21° C. and 90 per cent, relative humidity). Eighty-five per cent, was the lowest record of the controls hatched successfully under these conditions. 2. The processes of maturation and fertilization were not studied. 3. Cleavage begins 12-13 hours after incubation. At 25 hours there are 32 nuclei. Yolk-cells are derived from cleavage nuclei, and they multiply by mitosis up to 50 hours. Blastoderm formation is complete after 55-60 hours of incubation. 4. The ventral embryonic rudiment is similar to that of many other insects. As soon as it is formed, germ-cells are budded off at the posterior pole of the egg. 5. The first stage in blastokinesis is fully described. 6. The formation of the mesoderm is by invagination and overgrowth. 7. The endoderm arises from two proliferating areas situated anteriorly and posteriorly. 8. Numerous cells are given off into the yolk during the early development of the embryo. There they disintegrate.

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Development of the germ cells and reproductive primordia in male and female embryos of Rhodnius prolixus Stål (Hemiptera: Reduviidae)

Canadian Journal of Zoology ◽

10.1139/z94-148 ◽

1994 ◽

Vol 72 (6) ◽

pp. 1100-1119 ◽

Cited By ~ 17

Author(s):

B. S. Heming ◽

E. Huebner

Keyword(s):

Germ Cells ◽

Dorsal Surface ◽

Interstitial Cells ◽

Rhodnius Prolixus ◽

Posterior Pole ◽

Male And Female ◽

Functional Aspects ◽

Pole Plasm ◽

Blastodermal Cells ◽

Sheath Cells

Newly deposited eggs of Rhodnius prolixus lack a visible pole plasm and require 14 days to develop at 27 °C and 70% RH. The first germ cells originate at 9% of embryogenesis by asynchronous mitosis of blastodermal cells behind the germ Anlage at the posterior pole of the egg. From 9 to 17%, these proliferate to a mean of 270 cells and, from 13 to 18%, migrate forward over the dorsal surface of the mesoderm and lodge in abdominal segments 3–7. Between 22 and 30%, they shift laterally and segregate into three or four paired clumps between segments 3 and 4, 4 and 5, 5 and 6, and, sometimes, 6 and 7 and, from 30 to 37%, gradually assemble into a continuous longitudinal mass on either side of segments 3–6, where they begin to associate with mesodermal cells. Between 37 and 46%, these collect between (males) and around the germ cells to form the rudiments of the terminal filaments (females), inner and outer gonadal sheaths, interstitial cells (males), and primary exit ducts. Dorsally situated sheath cells then invaginate ventrally into each gonadal rudiment, partitioning it into seven compartments, each containing a mean of 15 oogonia or 16 spermatogonia. These seem to fuse into a rosette, at least in females, but do not begin to divide again until after hatch. Excluded germ cells lodge within the rudiments of one or both exit ducts. The evolutionary and functional aspects of our findings are addressed and new observations are presented on the mechanism of anatrepsis.

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Correction to Graphene Quantum Dots Alter Proliferation and Meiosis of Germ Cells Only in Genetic Females of Japanese Medaka during Early Embryonic Development

ACS Applied Bio Materials ◽

10.1021/acsabm.9b00365 ◽

2019 ◽

Vol 2 (5) ◽

pp. 2294-2294

Author(s):

Sreelakshmi Krishnakumar ◽

Vinod Paul ◽

Ajish Ariyath ◽

Puthiyoth Dayanandan Anoop ◽

Sajini Sreekumar ◽

...

Keyword(s):

Quantum Dots ◽

Embryonic Development ◽

Germ Cells ◽

Graphene Quantum Dots ◽

Early Embryonic Development ◽

Japanese Medaka

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Importance of Temperature and Humidity Control in Rubber Testing. II—Resistance to Abrasion

Rubber Chemistry and Technology ◽

10.5254/1.3535412 ◽

1929 ◽

Vol 2 (4) ◽

pp. 680-697

Author(s):

W. A. Gibbons ◽

J. M. Bierer ◽

E. R. Bridgewater ◽

D. F. Cranor ◽

C. R. Park ◽

...

Keyword(s):

Relative Humidity ◽

Experimental Error ◽

Negligible Effect ◽

Stress Strain ◽

Humidity Control ◽

Temperature Changes ◽

Constant Relative Humidity ◽

Temperature And Humidity ◽

Cent Relative Humidity ◽

Great Error

Abstract This study shows that in determining resistance to abrasion the temperature of the room or cabinet should be controlled within ± 1 ° C. in order to avoid significant errors in the results from this source. Below are shown the percentage differences per degree Centigrade obtained with each of the stocks. It must be remembered that this probably holds only over the range of temperatures studied and might change rapidly outside of this range. As the temperature changes from 15 ° C. to 35 ° C., the resistance to abrasion changes per degree Centigrade in the following manner: In the light of the present investigation there will be no great error in results caused by differences in relative humidity either with the raw or vulcanized stock. Where laboratories are equipped to condition raw and vulcanized stock for stress-strain tests, it appears that it would be advisable also to condition samples for determining resistance to abrasion. It would at least tend to produce more nearly uniform results by eliminating possible sources of small errors. As the relative humidity during exposure of raw stock increases from 10 per cent to 100 per cent, the resistance to abrasion per 1 per cent relative humidity changes roughly in the following manner: As these variations are small compared with the experimental error, it is evident that if the relative humidity does not vary over too wide a range its effect may be neglected. The temperature of storing the cured samples while maintaining a constant relative humidity has a negligible effect as in the case of relative humidity. As the temperature increases the resistance to abrasion per degree changes in the following manner:

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The Conditions of Temperature and Humidity of the Air between the Skin and Shirt of Man

Journal of Hygiene ◽

10.1017/s0022172400017988 ◽

1932 ◽

Vol 32 (2) ◽

pp. 268-274 ◽

Cited By ~ 14

Author(s):

Kenneth Mellanby

Keyword(s):

Relative Humidity ◽

Temperature And Humidity ◽

Cent Relative Humidity

Methods for measuring the temperature and humidity of the air beneath the shirt are described.Conditions of temperature and humidity under the shirt are described, for a resting person, with external temperatures varying between 0° C. and 41° C., under different atmospheric humidities. The air beneath the shirt varied between 23° C. and 37° C., and 23 and 70 per cent. relative humidity. The saturation deficiency of the air beneath the shirt varied very little—only between 13 and 18 mm.—in all the observations taken.I am indebted to Dr P. A. Buxton for many helpful suggestions and for reading the manuscript. Also to Prof. G. H. F. Nuttall, F.R.S., for drawing my attention to literature on the earlier work.

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Effect of a Filter Cover on Temperature and Humidity in a Mouse Cage

Laboratory Animals ◽

10.1258/002367768781082852 ◽

1968 ◽

Vol 2 (2) ◽

pp. 113-120 ◽

Cited By ~ 12

Author(s):

M. L. Simmons ◽

D. M. Robie ◽

J. B. Jones ◽

L. J. Serrano

Keyword(s):

Relative Humidity ◽

Measured Temperature ◽

Ambient Conditions ◽

Fibrous Filter ◽

Water Filter ◽

Average Temperature ◽

Temperature And Humidity ◽

Cent Relative Humidity ◽

The Mean ◽

Heat And Moisture

To determine how a filter cap affects the heat and moisture build-up in a mouse cage, and how that build-up is affected by ambient conditions of temperature and relative humidity, 50 adult female mice were housed 10 per cage in polycarbonate cages, which were covered with a fibrous filter and sealed with a neoprene gasket and hold-down rod. The cages were placed in a chamber which controlled ambient temperature and humidity. Observations were made at 1°F intervals of temperature (68–74°F, 19.9–23.3°C) and at three different relative humidities (40, 55, and 70 per cent). Every 24 hours the chamber conditions were changed, and cages, bedding, water, filter caps, and food were replaced. Three sensors suspended just under the filter cover measured temperature and humidity and transmitted the data to a recorder. The first reading was taken after a 3-hour equilibraiion period, then every 3 hours until the next day's change. By measuring the average temperature and humidity, it was possible to study the differences between cage and ambient conditions. At 68°F (19.9°C) and 40 per cent relative humidity, the mean conditions in the cages were 72°F (22.2°C) and 50 per cent; at the upper limit of 74°F (23.3 °C) and 70 per cent, the mean cage conditions were 78°F (25.5°C) and 75 per cent.

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Importance of Temperature and Humidity Control in Rubber Testing. Progress Report of the Physical Testing Commitee, Rubber Division, A.C.S. (Dated Dec. 8, 1927)

Rubber Chemistry and Technology ◽

10.5254/1.3535283 ◽

1928 ◽

Vol 1 (1) ◽

pp. 182-191

Author(s):

J. E. Partenheimer ◽

E. R. Bridgwater ◽

D. F. Cranor ◽

E. B. Curtis ◽

J. W. Schade ◽

...

Keyword(s):

Relative Humidity ◽

Absolute Humidity ◽

Rubber Compounds ◽

Physical Testing ◽

Temperature And Humidity ◽

Cent Relative Humidity ◽

Physical Tests ◽

A Minor ◽

Mixed Stock ◽

Testing Room

Abstract The purpose of the work which this committee has undertaken is to determine the effect of the variables which influence the results of physical tests on rubber. The investigation has proven that variations in temperature which may occur from day to day in an uncontrolled testing room may affect the physical tests to as great a degree as a 25 to 40 per cent change in the time of cure, while relative humidity affects the results to only a minor degree. Furthermore, variations in the absolute humidity of the room in which the unvulcanized rubber is stored between the time of mixing and the time of curing may affect the tensile strength and modulus of rubber compounds to as great a degree as does the temperature after curing. It is, therefore, apparent that laboratory tests which are conducted under uncontrolled conditions of temperature and humidity may give highly erroneous results and may even give misinformation which is worse than no information at all. The committee, therefore, recommends that mixed stock prior to curing and cured stock prior to testing be conditioned for not less than twenty-four nor more than twenty-eight hours at 82 deg. F. ± 2 deg. and 45 per cent relative humidity ± 3 per cent and that the testing room be maintained at 82 deg. F. ± 2 deg. If a temperature of 82 deg. F. cannot be maintained for conditioning the mixed stock prior to curing, the committee recommends a relative humidity corresponding to the temperature used which gives an absolute humidity equal to that obtained under the former conditions. The temperature of the testing room should be controlled within the above stated limits, but it is not necessary to control the humidity of the entire room. A small conditioning cabinet in which the standard humidity is maintained has been found to be sufficient.

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Graphene Quantum Dots Alter Proliferation and Meiosis of Germ Cells Only in Genetic Females of Japanese Medaka during Early Embryonic Development

ACS Applied Bio Materials ◽

10.1021/acsabm.8b00606 ◽

2019 ◽

Vol 2 (2) ◽

pp. 737-746

Author(s):

Sreelakshmi Krishnakumar ◽

Vinod Paul ◽

Ajish Ariyath ◽

Puthiyoth Dayanandan Anoop ◽

Sajini Sreekumar ◽

...

Keyword(s):

Quantum Dots ◽

Embryonic Development ◽

Germ Cells ◽

Graphene Quantum Dots ◽

Early Embryonic Development ◽

Japanese Medaka

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The early embryonic development of the satellite organism Pristionchus pacificus: differences and similarities with Caenorhabditis elegans

Nematology ◽

10.1163/156854108783900267 ◽

2008 ◽

Vol 10 (3) ◽

pp. 301-312 ◽

Cited By ~ 10

Author(s):

Gaetan Borgonie ◽

Wim Bert ◽

Wouter Houthoofd ◽

Sandra Vangestel

Keyword(s):

Caenorhabditis Elegans ◽

Embryonic Development ◽

Early Development ◽

Model Organism ◽

Embryonic Cell ◽

Early Embryonic Development ◽

Cell Contacts ◽

Pristionchus Pacificus ◽

C Elegans ◽

Cell Cell

AbstractAs a comparative counterpart for the model organism Caenorhabditis elegans, the nematode Pristionchus pacificus was established as a satellite organism to study developmental processes. However, these studies mainly focused on post-embryonic development and little is known about the early embryonic development. Using 4D microscopy we reconstructed the early embryonic cell lineage of 12 individuals of P. pacificus. By analysing several parameters of early development, including the division sequence, the spatial arrangement of blastomeres, the cell cycle patterns of the AB lineage and cell-cell contacts in different cell stages of the embryo, it was shown that the early embryonic development is nearly identical to C. elegans. Known cell-cell contacts necessary for induction of blastomere fates in C. elegans are also present in P. pacificus. Thus, the spatio-temporal conditions that would allow possible homologous inductions are present. However, at least one model for blastomere specification seems not to apply to P. pacificus since the third division in the AB lineage differs from that of C. elegans. Furthermore, naturally occurring variability of early development was demonstrated, which is clearly permitted since there seems to be no influence on further development into an adult worm.

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