Embryoscope - An Advanced Embryo Monitoring Biomedical Instrument

Embryoscope is a machine which is used to monitor embryo from the time of conception. It allows fertility specialist to select the most viable embryo during in-vitro fertilization. This instrument reduces the risk of taking embryo from the incubator for observation. It can monitor 12 embryos at once and take photos of each embryo every 5 to 10 minutes during the entire incubation period. With the help of this instrument, fertility expert can also monitor the abnormality in embryo. The embryoscope is an incubator with an integrated camera. The detection of abnormality can be done without harming the embryo.

Light and electron microscopy study of late embryonic development in the land snail Limicolaria flammea (Müller) (Pulmonata, Achatinidae)

The late stages of embryogenesis in the achatinid land snail Limicolariaflammea (Müller, 1774) were described using light and electron microscopy. Embryos at various stages of development were present in the eggs during the first hour after they were laid, from 4-cell blastulae to morulae and fairly advanced stages. The advanced embryo which was fully developed on the second day bears a long cephalic sac, first to be developed, attached to the embryo and a podocyst which is attached to the foot of the embryo. Both of these structures are reduced in size as embryogenesis progresses until they finally disappear at about the 7th day after the egg was deposited. The embryonic shell was apparent on the second day and spiral coiling was apparent at about day 5. The spiral shell had one whorl when formed and more spirals were added so that at hatching the young snails had three whorls.

Embryos produced in vitro from bulls carrying 16;20 and 1;29 Robertsonian translocations: efficiency and kinetics of oocyte fertilization and embryo development

The present experiments were designed to study the effects of Robertsonian translocations on the efficiency and kinetics of in vitro fertilization and early and advanced embryo development. Spermatozoa from bulls with rob(16;20), rob(1;29) and normal karyotype (A, B and C, respectively) were used. Oocytes were matured, fertilized and cultured by the standard protocol described previously. Twenty-four hours after fertilization, adequate numbers of oocytes were fixed, stained and examined. The development of embryos was evaluated on days 2 (D2), 7 (D7) and 8 (D8) after fertilization. The rate of normally fertilized oocytes was significantly lower (p≤0.01) for bull A than for bulls B and C. However, no significant differences in the kinetics of fertilization were found between bulls A, B and C. The D2 cleavage rate of embryos was significantly lower (p≤0.01) for bull A than for bulls B and C. Both D7 and D8 blastocyst rates for bull A or bull B were significantly lower (p≤0.01 or p≤0.01) than those for bull C. The percentages of both D7 advanced blastocysts and D8 expanded blastocysts were significantly lower (p≤0.01) for bulls A and B than for bull C. In conclusion, for rob(16;20), the efficiency of fertilization was strongly reduced; it resulted in low early and advanced embryo development. On the other hand, for the rob(1;29), neither fertilization nor early embryo development were affected and only advanced embryo development was decreased. But for both translocations, blastocyst formation was significantly delayed.

The effects of embryo stage and cell number on the composition of mouse aggregation chimaeras

Studies with intact preimplantation mouse embryos and some types of chimaeric aggregates have shown that the most advanced cells are preferentially allocated to the inner cell mass (ICM) rather than the trophectoderm. Thus, differences between 4-cell and 8-cell stage embryos could contribute to the tendency for tetraploid cells to colonise the trophectoderm more readily than the ICM in 4-cell tetraploid[harr ]8 cell diploid chimaeras. The aim of the present study was to test whether 4-cell stage embryos in 4-cell diploid[harr ]8-cell diploid aggregates contributed equally to all lineages present in the E12.5 conceptus. These chimaeras were compared with those produced from standard aggregates of two whole 8-cell embryos and aggregates of half an 8-cell embryo with a whole 8-cell embryo. As expected, the overall contribution of 4-cell embryos was lower than that of 8-cell embryos and similar to that of half 8-cell stage embryos. In the 4-cell[harr ]8-cell chimaeras the 4-cell stage embryos did not contribute more to the trophectoderm than the ICM derivatives. Thus, differences between 4-cell and 8-cell embryos cannot explain the restricted tissue distribution of tetraploid cells previously reported for 4-cell tetraploid[harr ]8-cell diploid chimaeras. It is suggested that cells from the more advanced embryo are more likely to contribute to the ICM but, for technical reasons, are prevented from doing so in simple aggregates of equal numbers of whole 4-cell and whole 8-cell stage embryos.

Contribution of the pentose phosphate pathway to glucose utilization by preimplantation sheep embryos

The activity of the pentose phosphate pathway of glucose metabolism in early sheep embryos and in the structures of the advanced conceptus from Day 13 to Day 19 of pregnancy was measured quantitatively during a 2.5-h incubation with glucose as sole energy source. For embryos during cleavage, activity of this pathway accounted for 6-9% of total glucose utilized. The proportion of glucose metabolized through the pentose pathway fell progressively with development and by Day 19 represented 1-2% of glucose turnover. However, total turnover of glucose increased eight fold between the 2-cell and blastocyst stage and the amount of glucose processed through the pentose pathway increased over this time despite the fall in the proportion utilized in this way. In contrast, glucose turnover by the advanced embryo and its extra embryonic membranes progressively decreased as the structures developed. As a result, estimates of the amount of glucose utilized through the pathway per microgram dried weight per hour declined to low values at Day 19 following the peak in activity at about the time of blastulation. Trophoblast and yolk sac processed less glucose through the pentose pathway per microgram dried weight than embryonic tissue but the allantois was similar to the embryo. Overall, the pentose pathway accounted for a relatively constant proportion of the CO2 produced from glucose under these experimental conditions with values generally between 15 and 20% of total CO2 produced. When activities in the components of the advanced conceptus were expressed as the total amount of glucose processed through the pathway per hour, turnover in the embryo, allantois and yolk sac increased progressively with time. By contrast, there was a substantial trough in the activity of the trophoblast on Day 17 of pregnancy.

Parthenogenetic development of mouse embryos in vivo

CBA-p and CBA-T6T6 females were mated with vasectomized males of A strain and early in the morning the eggs were activated in situ with the electric shock of 30, 40 and 50 V. Females were killed between the 5th and the 10th day of pregnancy and the implantation sites were studied histologically or their content was examined under the dissecting microscope. Of the uterine horns, 43·6% contained at least one implantation and the mean number of implantations per horn was 0·76. Altogether 152 implantations were collected. The implantation rate was twice as high in older females (12 weeks and over) as in young ones (6–8 weeks). The number of living embryos decreased with every day so that on the 9th and 10th day only 2 out of 86 embryos were alive (2·3%). With one exception all embryos which were alive at the time of examination were retarded in development for approximately 1 day. The most advanced embryo was at the 8-somite stage. Two attempts aimed at increasing the synchrony between the embryos and the uterus at the time of implantation (activation immediately after delayed mating and transfer of 4·5-day embryos to 3·5-day uterus) did not improve the survival of embryos after implantation.

EMBRYOLOGY OF INTERSPECIFIC CROSSES IN MELILOTUS

Twelve species of Melilotus were intercrossed and the embryology of the hybrids was studied. The species involved in this study are M. alba, M. officinalis, M. suaveolens, M. polonica, M. dentata, M. altissima, M. hirsutus, M. taurica, M. messanensis, M. italica, M. sulcat, and M. speciosa. Among partially compatible crosses, M. officinalis × M. alba produces the most advanced embryo. Growth of the embryo proceeds normally until about eight days, and more slowly thereafter until the 12th or 13th day, when growth is completely inhibited and the embryo aborts. The reciprocal M. alba × M. officinalis embryo does not grow as large or differentiate as much before aborting by the 11th day. Other crosses, including M. officinalis × M. suaveolens and M. alba × M. messanensis form a normal proembryo that grows slowly to about the sixth day. The proembryo then loses polarity, organ development becomes abnormal, and the ovule aborts about the 12th day. Aborted embryos are also produced in the cross, M. alba × M. dentata. Reciprocal crosses of M. suaveolens and M. altissima and M. altissima × M. polonica produce essentially normal embryos up to eight days. These crosses may be sources of economically important germ plasm. Crosses of M. altissima × M. alba and M. italica × M. altissima exhibit early embryo abortion. The suspensor becomes necrotic in four or five days and the proembryo floats into the ovule cavity, which contains abundant noncellular endosperm. In the cross M. officinalis × M. altissima, neither the zygote nor the primary endosperm nucleus divides. When M. altissima is used as the female parent, the zygote does not divide but the endosperm proliferates. In the cross, M. italica × M. officinalis, neither the zygote nor the endosperm divides. Embryos of M. italica × M. sulcata grow for four or five days, but the primary endosperm nucleus does not divide. The hybrid seed of M. alba × M. suaveolens weighs less than seed of either parent. Although developing ovules are smaller than those of M. suaveolens × M. alba, the embryo of the former is much larger and more differentiated, and endosperm is more abundant. This relationship between these two compatible species is of particular theoretical interest. Although many of the crosses do not mature viable seed, some embryos develop normally to a point where they would be worthy subjects for culture on nutrient agar.

A Study of the Embryonic development of the Gooseberry Sawfly, Pteronidea Ribesii

The following points in the descriptive embryology of the sawfly appear to be important especially for comparison with the higher Hymenoptera, e.g. the honey bee. 1. The earlier stages of development (formation of the blastoderm, germinal layers, &c.) take relatively more time in the honey bee than in the sawfly, while the later stages of development (organogenesis) take more time in the sawfly. 2. Only two well-defined germ layers are formed--the outer (ectoderm) and the inner (mesoderm). Cells proliferate from the mid-ventral area of the germ band and spread out to form the inner layer in the sawfly, whereas in the honey bee it forms as a middle plate. Localized proliferations at the anterior and the posterior end of the germ band form two cell-clumps; from these differentiate the midgut epithelium, mesoderm of the procephalic region of the head, muscle layer of the proctodaeum and stomodaeum, and also the germ cells. These are here called the mesendoderm rudiments. The coelom sacs are not well defined from each other but form a more or less continuous tube as in the honey bee. 3. Nucleoli appear in the cells and the cytoplasm becomes basiphil immediately after the formation of the inner layer. Changes in the basiphilia of cells during development are described. 4. The proctodaeum first appears as an invagination in the upturned (dorsal) part of the germ band, which is all used up in its formation, and the edges of the ventral germ band rise up to complete the dorsal closure. The Malpighian tubules develop from the blind end of the proctodaeum and are regarded here as ectodermal; in the honey bee they develop before the proctodaeum is formed. In the advanced embryo the midgut cells have big vacuoles in them and throw out pseudopodia into the lumen of the gut, and the cells of the salivary gland acquire large lobed nuclei. 5. Agreement is expressed with Snodgrass's view (1938) that the head is composed of four segments and a procephalic region. The labrum has a paired origin (in the honey bee it is unpaired in origin); and as in the honey bee the premandibular segment is not developed. The rest of the body is composed of three thoracic and ten abdominal segments. Paired appendages appear on the thoracic and the second to seventh and tenth abdominal segments (in the honey bee abdominal appendages are not formed). 6. The germ cells arise from the posterior mesendodermal rudiment. In the honey bee they appear tto be derived from the genital ridges. 7. There are no blastokinetic movements as in the honey bee. 8. The serosa persists till the hatching of the embryo and secretes a cuticle at an early age. The amnion is not well developed and is transitory; in the honey bee only one embryonic envelope forms.