scholarly journals Ovulation and Embryonic Developmental Rate Following hCG-stimulation in Sows

2000 ◽  
Vol 41 (3) ◽  
pp. 321-328
Author(s):  
A. K. Nissen ◽  
M. Schmidt ◽  
P. Hyttel ◽  
T. Greve
Keyword(s):  
Developmental Rate

BIOASSAY OF THYROID HORMONE USING HYPOTHYROID TADPOLES

1962 ◽  
Vol 41 (1) ◽  
pp. 143-153 ◽  
Author(s):  
U. Henriques
Keyword(s):  
Thyroid Hormone ◽  
Dose Response ◽  
Developmental Rate ◽  
Response Curves ◽  
Sodium Salts ◽  
Dose Response Curves

ABSTRACT A bioassay of thyroid hormone has been developed using Xenopus larvae made hypothyroid by the administration of thiourea. Only tadpoles of uniform developmental rate were used. Thiourea was given just before the metamorphotic climax in concentrations that produced neoteni in an early metamorphotic stage. During maintained thiourea neotoni, 1-thyroxine and 1-triiodothyronine were added as sodium salts to the water for three days and at the end of one week the stage of metamorphosis produced was determined. In this way identical dose-response curves were obtained for the two compounds. No qualitative differences between their effects were noted except that triiodothyronine seemed more toxic than thyroxine in equivalent doses. Triiodothyronine was found to be 7–12 times as active as thyroxine.

scholarly journals A Brief Incubation of Cumulus-Enclosed Mouse Eggs in a Calcium-Free Medium Containing a High Concentration of Calcium-Chelator Markedly Improves Preimplantation Development

2020 ◽  
Vol 17 (10) ◽  
pp. 3505
Author(s):  
Valeria Merico ◽  
Silvia Garagna ◽  
Maurizio Zuccotti
Keyword(s):  
In Vitro Fertilization ◽  
Mammalian Species ◽  
Developmental Rate ◽  
Cumulus Cells ◽  
Fertilization Rate ◽  
Preimplantation Development ◽  
High Concentration ◽  
Vitro Fertilization ◽  
Positive Effects

The presence of cumulus cells (CCs) surrounding ovulated eggs is beneficial to in vitro fertilization and preimplantation development outcomes in several mammalian species. In the mouse, this contribution has a negligible effect on the fertilization rate; however, it is not yet clear whether it has positive effects on preimplantation development. Here, we compared the rates of in vitro fertilization and preimplantation development of ovulated B6C3F1 CC-enclosed vs. CC-free eggs, the latter obtained either after a 5 min treatment in M2 medium containing hyaluronidase or after 5–25 min in M2 medium supplemented with 34.2 mM EDTA (M2-EDTA). We found that, although the maintenance of CCs around ovulated eggs does not increment their developmental rate to blastocyst, the quality of the latter is significantly enhanced. Most importantly, for the first time, we describe a further quantitative and qualitative improvement, on preimplantation development, when CC-enclosed eggs are isolated from the oviducts in M2-EDTA and left in this medium for a total of 5 min prior to sperm insemination. Altogether, our results establish an important advancement in mouse IVF procedures that would be now interesting to test on other mammalian species.

Biological traits of the predatory mirid Macrolophus praeclarus, a candidate biocontrol agent for the Neotropical region

2021 ◽  
pp. 1-9
Author(s):  
Meritxell Pérez-Hedo ◽  
Carolina Gallego ◽  
Amy Roda ◽  
Barry Kostyk ◽  
Mónica Triana ◽  
...  
Keyword(s):  
Developmental Rate ◽  
Predation Rate ◽  
Developmental Time ◽  
Control Treatment ◽  
Thermal Constant ◽  
Biological Traits ◽  
Pest Species ◽  
Tomato Plants ◽  
Defensive Responses ◽  
Predatory Mirid

Abstract The predatory mirid Macrolophus praeclarus is widely distributed throughout the Americas, and is reported to prey upon several horticultural pest species. However, little is known about its biology, thermal requirements, crop odour preferences, phytophagy, and capability to induce defensive responses in plants. When five temperatures studied (20, 25, 30, 33 and 35°C) were tested and Ephestia kuehniella was used as prey, the developmental time from egg to adult on tomato, was longest at 20°C (56.3 d) and shortest at 33°C (22.7 d). The ability of nymphs to develop to adults decreased as the temperature increased, with the highest number of nymphs reaching the adult stage at 20°C (78.0%) and lowest at 35°C (0%). The lower and upper developmental thresholds were estimated at 11.2° and 35.3°C, respectively. The maximum developmental rate occurred at 31.7°C and the thermal constant was 454.0 ± 8.1 degree days. The highest predation rate of E. kuehniella eggs was obtained at 30°C. In Y-tube olfactory choice tests, M. praeclarus selected tomato, sweet pepper and eggplant odours more frequently than no plant control treatment. Macrolophus praeclarus feeding did not damage tomato plants compared to another zoophytophagous mirid, Nesidiocoris tenuis, which caused necrotic rings. The phytophagy of M. praeclarus induced defensive responses in tomato plants through the upregulation of the jasmonic acid metabolic pathway. The implications of the findings for using M. praeclarus in tomato biological control programmes in the Americas are discussed.

Developmental divergence among hatchery strains of rainbow trout (Salmo gairdneri). I. Pure strains

1985 ◽  
Vol 27 (3) ◽  
pp. 289-297 ◽  
Author(s):  
Moira M. Ferguson ◽  
Roy G. Danzmann ◽  
Fred W. Allendorf
Keyword(s):  
Rainbow Trout ◽  
Morphological Analysis ◽  
Developmental Process ◽  
Developmental Rate ◽  
Electrophoretic Analysis ◽  
Development Rate ◽  
Salmo Gairdneri ◽  
Glucosephosphate Isomerase ◽  
Hatching Time ◽  
Developmental Divergence

We compare the developmental rate of six closely related hatchery strains of rainbow trout. Hatching time, morphological analysis, and the pattern of ontogenetic change in lactate dehydrogenase, malate dehydrogenase, glucosephosphate isomerase, and phosphoglucomutase activities indicate significant differences in developmental rate between strains. There is close concordance among the different measures of developmental rate. Strains with higher levels of heterozygosity, as estimated from electrophoretic analysis of 42 loci, developed faster than less heterozygous strains. The variation in developmental rate in these closely related strains indicates that there is substantial genetic variation affecting the developmental process in rainbow trout.Key words: development rate, intraspecific variation, rainbow trout.

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