The embryonic development of the swimming behavior of Daphnia pulex (Crustacea: Cladocera)

1972 ◽  
Vol 50 (7) ◽  
pp. 969-973 ◽  
Author(s):  
Michael Berrill ◽  
Colin Henderson
Keyword(s):  
Embryonic Development ◽  
Daphnia Pulex ◽  
Swimming Behavior ◽  
Egg Membrane ◽  
First Time

The embryo of Daphnia pulex sheds two egg membranes and then molts once before completing its development. The second antennae, used for swimming by the fully developed individual, move for the first time shortly before the shedding of the second egg membrane. These antennal movements occur in bouts which appear to be pseudo-rhythmic in organization. The antennae are not raised to their swimming positions until several hours before the molt which terminates embryonic development, at which time they become increasingly active. The onset and subsequent elaboration of antennal activity is therefore closely correlated with the shedding of embryonic membranes.

Revision of several poorly known Antarctic aeolid nudibranch species (Mollusca: Gastropoda), with the description of a new species

2011 ◽  
Vol 92 (5) ◽  
pp. 1161-1174 ◽  
Author(s):  
Ángel Valdés ◽  
Amy L. Moran ◽  
H. Arthur Woods
Keyword(s):  
New Species ◽  
Embryonic Development ◽  
Ross Sea ◽  
Egg Mass ◽  
Morphological Examination ◽  
Antarctic Species ◽  
External Appearance ◽  
Reproductive Anatomy ◽  
First Time ◽  
A New Species

Morphological examination of several specimens of aeolid nudibranchs collected from the Ross Sea, Antarctica, revealed an unexpectedly high number of species. Based on the collected material the following species are re-described and for the first time their colour, reproductive anatomy and radula are illustrated together: Eubranchus glacialis, Cuthona modesta, Cuthona crinita, Cuthona elioti and Guyvalvoria paradoxa. Additionally, a new species of Cuthona is described from this area. The new species differs from other Antarctic and sub-Antarctic species of Cuthona in its external appearance, radular morphology and reproductive anatomy. Information on the egg mass and embryonic development of several species is provided.

scholarly journals Embryonic development of Anodontites trapesialis (Lamarck, 1819) (Bivalvia: Mycetopodidae)

2011 ◽  
Vol 71 (1) ◽  
pp. 139-144 ◽  
Author(s):  
AT. Silva-Souza ◽  
P. Guardia-Felipi ◽  
NR. Arrebola
Keyword(s):  
Electron Microscopy ◽  
Embryonic Development ◽  
Phase Iii ◽  
Fish Farms ◽  
Egg Envelope ◽  
Initial Stage ◽  
Phases Of Development ◽  
Five Phases ◽  
First Time ◽  
Scanning Electron

The phases of embryonic development of Anodontites trapesialis lasidia are described for the first time. Adult specimens were obtained from two fish farms located in Londrina, Paraná, Brazil. The internal demibranchs of 120 individuals were studied using a routine histological technique; 70 of these carried eggs and/or larvae in the marsupium and were utilized for the description of the phases of embryonic development. The demibranchs of five specimens were evaluated by scanning electron microscopy to detail the morphology of the larvae. Five phases of development were established: phase I, corresponding to the initial stage of cleavage with the formation of apical cells; phase II, including the stages of the morula and blastula; phase III, where the gastrula forms; phase IV, where the larva formed is still inside the egg envelope; and phase V, where the lasidium can still be identified immediately after eclosion.

Effect of sperm pretreatment with sodium hydroxide and dithiothreitol on the efficiency of bovine intracytoplasmic sperm injection

2014 ◽  
Vol 26 (6) ◽  
pp. 847 ◽  
Author(s):  
M. E. Arias ◽  
R. Sánchez ◽  
J. Risopatrón ◽  
L. Pérez ◽  
R. Felmer
Keyword(s):  
Embryonic Development ◽  
Intracytoplasmic Sperm Injection ◽  
Membrane Integrity ◽  
Control Group ◽  
Developmental Potential ◽  
Bovine Spermatozoa ◽  
Pronuclear Formation ◽  
First Time ◽  
In Vitro Embryonic Development

The efficiency of intracytoplasmic sperm injection (ICSI) in bovines is lower than in other species due, in part, to a lack of optimal conditions for its implementation; this has hindered the achievement of high rates of embryonic development and the birth of live offspring. The aim of the present study was to evaluate the effects of pretreatment of bovine spermatozoa with NaOH and dithiothreitol (DTT) on the viability, plasma membrane integrity, DNA fragmentation and in vitro developmental potential of embryos generated by ICSI. Following pretreatment of spermatozoa with 5 mM DTT for 20 min and a low concentration of NaOH (1 mM for 60 min), there were fewer live and acrosome reacted spermatozoa (44% and 34%, respectively) than in the control group without treatment (82%). Spermatozoa subjected to higher alkali concentrations (10–50 mM) were mostly dead and reacted. However, pronuclear formation, cleavage, blastocyst rate and embryo quality did not differ between these pretreatment groups and the untreated control group. In conclusion, we have described, for the first time, the effects of NaOH treatment on bovine spermatozoa and subsequent in vitro embryonic development after ICSI, and have demonstrated that pretreatment of bovine spermatozoa with NaOH or DTT is not necessary for an appropriate in vitro embryo development in this species.

Behavioral responses of a herbivorous calanoid copepod to the presence of other zooplankton

1986 ◽  
Vol 64 (7) ◽  
pp. 1422-1425 ◽  
Author(s):  
C. K. Wong ◽  
C. W. Ramcharan ◽  
W. G. Sprules
Keyword(s):  
Calanoid Copepod ◽  
Defense Mechanism ◽  
Interference Competition ◽  
Daphnia Pulex ◽  
Behavioral Responses ◽  
Behavioral Flexibility ◽  
Rest Period ◽  
Swimming Behavior ◽  
Potential Competitor

Swimming behavior of the herbivorous calanoid copepod Diaptomus minutus consists of periods of rest interrupted by short jumps. Jumping frequency decreased in the presence of predatory copepods and increased in the presence of the herbivorous Daphnia pulex, a potential competitor. Because D. minutus is detected by vibration-sensitive predators when it jumps, its response in the presence of predators may be a prey defense mechanism. Since feeding by D. minutus takes place during the rest period and is interrupted by jumps, the response to the presence of D. pulex may indicate interference competition. The results demonstrate the behavioral flexibility of zooplanktonic organisms.

scholarly journals Early development of the red mouthed goby, Gobius cruentatus (Pisces: Gobiidae)

2002 ◽  
Vol 82 (1) ◽  
pp. 161-163 ◽  
Author(s):  
Fátima Gil ◽  
Rita Borges ◽  
Cláudia Faria ◽  
Emanuel J. Gonçalves
Keyword(s):  
Embryonic Development ◽  
Early Development ◽  
Exogenous Feeding ◽  
Total Length ◽  
Newly Hatched Larvae ◽  
First Time

The full developmental embryonic sequence of Gobius cruentatus is described for the first time. Embryonic development lasted 13 days (14·0–15·0°C). The newly hatched larvae (3·3 mm total length) presented pigmented eyes, the yolk is fully absorbed, and the mouth and anus were opened allowing the onset of exogenous feeding almost after hatching.

Unusual Vascular Malformation of the Kidney in Both Twins of a Monozygotic Pair: Short Case Report

1987 ◽  
Vol 36 (4) ◽  
pp. 567-570
Author(s):  
G. Mastroberardino ◽  
A. Sciarra ◽  
R. Gualtieri ◽  
C. Di Fusco ◽  
P. Grammatico ◽  
...  
Keyword(s):  
Case Report ◽  
Embryonic Development ◽  
Blood Group ◽  
Vascular Malformation ◽  
Embryological Development ◽  
Clinical Tests ◽  
Renal Vessels ◽  
First Time

AbstractA case of double bilateral renal vessels in both twins of a MZ pair is reported for the first time. Even in non-twins, the anomalies reported so far involved the inferior polar arteries in agreement with the embryological development. The two male twins, examined at the age of 14 years, had simultaneously developed a marked hypertension at the age of 7 years. Zygosity was determined by blood group and HLA analysis and various clinical tests were carried out to diagnose the condition. It is suggested that the anomaly is the result of a genetically induced early block in embryonic development.

scholarly journals Conventional PKCs regulate the temporal pattern of Ca2+ oscillations at fertilization in mouse eggs

2004 ◽  
Vol 164 (7) ◽  
pp. 1033-1044 ◽  
Author(s):  
Guillaume Halet ◽  
Richard Tunwell ◽  
Scott J. Parkinson ◽  
John Carroll
Keyword(s):  
Embryonic Development ◽  
Temporal Pattern ◽  
Physiological Function ◽  
Egg Activation ◽  
Present Evidence ◽  
Downstream Effectors ◽  
Living Mouse ◽  
Egg Membrane ◽  
Mammalian Eggs ◽  
Mouse Eggs

In mammalian eggs, sperm-induced Ca2+ oscillations at fertilization are the primary trigger for egg activation and initiation of embryonic development. Identifying the downstream effectors that decode this unique Ca2+ signal is essential to understand how the transition from egg to embryo is coordinated. Here, we investigated whether conventional PKCs (cPKCs) can decode Ca2+ oscillations at fertilization. By monitoring the dynamics of GFP-labeled PKCα and PKCγ in living mouse eggs, we demonstrate that cPKCs translocate to the egg membrane at fertilization following a pattern that is shaped by the amplitude, duration, and frequency of the Ca2+ transients. In addition, we show that cPKC translocation is driven by the C2 domain when Ca2+ concentration reaches 1–3 μM. Finally, we present evidence that one physiological function of activated cPKCs in fertilized eggs is to sustain long-lasting Ca2+ oscillations, presumably via the regulation of store-operated Ca2+ entry.

scholarly journals Pre-treatment of sperm reduces success of ICSI in the pig

Reproduction ◽  
2011 ◽  
Vol 142 (2) ◽  
pp. 285-293 ◽  
Author(s):  
Michiko Nakai ◽  
Junya Ito ◽  
Ken-ichi Sato ◽  
Junko Noguchi ◽  
Hiroyuki Kaneko ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Sperm Head ◽  
Oocyte Activation ◽  
Mammalian Sperm ◽  
Repeated Freezing ◽  
Pre Treatment ◽  
Triton X ◽  
First Time

In pigs, although ICSI is a feasible fertilization technique, its efficiency is low. In general, injected pig sperm are insufficient to induce oocyte activation and embryonic development. Pretreatments for disrupting sperm membranes have been applied to improve the fertility of ICSI oocytes; however, we hypothesize that such pretreatment(s) may reduce the ability of the sperm to induce oocyte activation. We first evaluated the effects of sperm pretreatments (sonication (SO) to isolate the sperm heads from the tails, Triton X-100 (TX), and three cycles of repeated freezing/thawing (3×-FT) for disrupting sperm membranes) on the rate of pronucleus (PN) formation after ICSI. We found that oocytes injected with control (whole) sperm had higher rates of PN formation than those obtained after subjecting the sperm to SO, TX, and 3×-FT. The amounts of phospholipase Cζ (PLCζ), which is thought to be the oocyte-activating factor in mammalian sperm, in sperm treated by each method was significantly lower than that in whole untreated sperm. Furthermore, using immunofluorescence, it was found that in pig sperm, PLCζ was localized to both the post-acrosomal region and the tail area. Thus we demonstrated for the first time that sperm pretreatment leads to a reduction of oocyte-activating capacity. Our data also show that in addition to its expected localization to the sperm head, PLCζ is also localized in the tail of pig sperm, thus raising the possibility that injection of whole sperm may be required to attain successful activation in pigs.

The Mechanism of Hardening of the Salmonid Egg Membrane after Fertilization or Spontaneous Activation

Development ◽  
1958 ◽  
Vol 6 (4) ◽  
pp. 546-568
Author(s):  
A. I. Zotin
Keyword(s):  
Mechanical Property ◽  
Embryonic Development ◽  
Mechanical Damage ◽  
Mechanical Injury ◽  
External Factors ◽  
Salmonid Fishes ◽  
Egg Membrane ◽  
Spontaneous Activation

The embryonic development of fishes proceeds under the protection of rigid egg membranes which preserve the embryo from mechanical injury. Salmonid fishes bury their eggs in sandy and stony ground so that they are particularly liable to mechanical damage. This is apparently the reason why the membrane of the salmonid embryo is extremely strong, resisting a load of 3–4 kg. per ovum (Gray, 1932; Hayes, 1942, 1949; Hayes & Armstrong, 1942; Zotin, 1953a). This mechanical property of the membrane does not appear immediately after fertilization or activation but is preceded by a whole set of processes which are elicited in the membrane by external factors and by the fertilized or activated egg itself. Thus, according to Manery, Fisher, & Moore (1947), hardening of the egg membranes in the speckled trout sets in 2 hours after the release of the egg into water.

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