The pattern of early cleavage of the marsupial frog Gastrotheca riobambae

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 781-789 ◽  
Author(s):  
E.M. del Pino ◽  
S. Loor-Vela
Keyword(s):  
Cell Shape ◽  
Slow Rate ◽  
Early Stage ◽  
Tight Coupling ◽  
Early Cleavage ◽  
Cell Stage ◽  
Midblastula Transition ◽  
Developmental Patterns ◽  
Cleavage Cycle ◽  
The Third

Comparison of early development of the marsupial frog Gastrotheca riobambae with Xenopus laevis suggests that the cleavage pattern of Xenopus and the tight coupling of events at the midblastula transition are features of the accelerated development of small amphibian eggs with aquatic reproduction, rather than generalized features of amphibian development. The large eggs of the marsupial frog Gastrotheca riobambae not only display an atypical holoblastic pattern of cleavage and a very slow rate of development, but the events of the midblastula transition are uncoupled, suggesting that amphibians may have a diversity of developmental patterns. Early cleavage of the egg, which measures about 3 mm in diameter, occurs mostly by meridional and vertical furrows. The first cleavage cycle takes about 16 to 20 h and about four days may be required to reach the midblastula stage. Cleavage becomes asynchronous at about the third cleavage cycle evidenced by the formation of cleavage furrows. However, during cleavage (up to 342-cells), the majority of the nuclei divide synchronously and only 15 to 40% of the nuclei of a given embryo have a different cleavage schedule. At the 8-cell stage, nucleoli become visible (approximately 24 h after amplexus), signaling that transcription of rRNA has started at this early stage. Cell motility was detected in three- to four-day old embryos and seems to be associated with changes in cell shape and with expansion of the blastocoel at this stage.

Comparative and phylogenetic perspectives of the cleavage process in tailed amphibians

Zygote ◽  
2014 ◽  
Vol 23 (5) ◽  
pp. 722-731 ◽  
Author(s):  
Alexey G. Desnitskiy ◽  
Spartak N. Litvinchuk
Keyword(s):  
Ambystoma Mexicanum ◽  
Published Data ◽  
Cleavage Pattern ◽  
Cell Stage ◽  
Midblastula Transition ◽  
The Third ◽  
Cleavage Process ◽  
Necturus Maculosus ◽  
Ensatina Eschscholtzii ◽  
Developmental Traits

SummaryThe order Caudata includes about 660 species and displays a variety of important developmental traits such as cleavage pattern and egg size. However, the cleavage process of tailed amphibians has never been analyzed within a phylogenetic framework. We use published data on the embryos of 36 species concerning the character of the third cleavage furrow (latitudinal, longitudinal or variable) and the magnitude of synchronous cleavage period (up to 3–4 synchronous cell divisions in the animal hemisphere or a considerably longer series of synchronous divisions followed by midblastula transition). Several species from basal caudate families Cryptobranchidae (Andrias davidianus and Cryptobranchus alleganiensis) and Hynobiidae (Onychodactylus japonicus) as well as several representatives from derived families Plethodontidae (Desmognathus fuscus and Ensatina eschscholtzii) and Proteidae (Necturus maculosus) are characterized by longitudinal furrows of the third cleavage and the loss of synchrony as early as the 8-cell stage. By contrast, many representatives of derived families Ambystomatidae and Salamandridae have latitudinal furrows of the third cleavage and extensive period of synchronous divisions. Our analysis of these ontogenetic characters mapped onto a phylogenetic tree shows that the cleavage pattern of large, yolky eggs with short series of synchronous divisions is an ancestral trait for the tailed amphibians, while the data on the orientation of third cleavage furrows seem to be ambiguous with respect to phylogeny. Nevertheless, the midblastula transition, which is characteristic of the model species Ambystoma mexicanum (Caudata) and Xenopus laevis (Anura), might have evolved convergently in these two amphibian orders.

Accessibility of the promoter sequence in the J-chain gene is regulated by chromatin changes during B-cell differentiation

1986 ◽  
Vol 6 (11) ◽  
pp. 4031-4038
Author(s):  
M E Minie ◽  
M E Koshland
Keyword(s):  
B Cell ◽  
Early Stage ◽  
Promoter Sequence ◽  
Immunoglobulin M ◽  
Chain Gene ◽  
B Cell Differentiation ◽  
Cell Stage ◽  
J Chain ◽  
Lymphoid Lines ◽  
Nuclease Digestion

The gene for the immunoglobulin M (IgM)-polymerizing protein, the J chain, is activated when the mature B cell is triggered to secrete pentamer IgM. Activation of the gene was found to be associated with chromatin changes in a 240-base-pair region at the 5' end of the gene. Analyses of lymphoid lines showed that the 5' region was resistant to nuclease digestion at the immature B-cell stage; it became slightly more accessible in mature B cells and cells at an early stage in the IgM response and then displayed an open, hypersensitive structure in IgM-secreting cells. In addition, analyses of normal, mitogen-stimulated lymphocytes showed that the open hypersensitive structure was coinducible with J-chain gene expression. These results suggest that the 5' chromatin changes precede transcription, making control sequences within the site accessible to regulatory factors.

FACES OF V.M. SHUKSHIN: MARTIN IDEN, HAMLET, STEPAN RAZIN

2021 ◽  
pp. 59-65
Author(s):  
Т.А. Богумил
Keyword(s):  
Early Stage ◽  
Socialist Realism ◽  
Crowding Out ◽  
Behavioral Models ◽  
Cluster Approach ◽  
Second Stage ◽  
The Third ◽  
Third Stage ◽  
Early Departure ◽  
First Time

В статье предлагается концепция жизни и творческого роста В.М. Шукшина сквозь призму тезаурусного и кластерного подходов. Объяснительными «персональными моделями» для интерпретации биографического текста писателя являются кластеры Мартина Идена, Гамлета и Степана Разина. Ранее биографы и литературоведы указывали на важность этих персон для Шукшина, но разрозненно. Впервые предпринята попытка свести указанные персональные модели воедино, в целостный сюжет становления писателя в пространстве культуры. На разных этапах эволюции автора доминирует одна из указанных моделей, последовательно сменяя друг друга, но не вытесняя, а «внахлест». Ранний этап творчества, ориентированный на стратегию Мартина Идена, является попыткой «вписаться» в наличный культурный мейнстрим. Выражено это в следовании поэтике соцреализма. Второй этап подспудно начинается с реабилитации отца Шукшина в 1956 года, когда актуализируется «гамлетовский комплекс», проявляющийся в чувстве вины перед отцом, через стратегию утаивания подлинного «я», мотивы чудаковатости. Третий этап связан с личностью реального исторического лица, Степана Разина, и выражается в открытом протесте против власти. Все важные для В.М. Шукшина поведенческие модели объединены мотивом одинокого противостояния враждебному социуму и имеют трагический финал, что обусловило ранний уход писателя и порождение мифов о насильственном характере его смерти. В.М. Шукшин одновременно был фигурой неординарной и типичной, что позволило его биографии стать «персональной моделью» для последующих авторов, выходцев из сельской глубинки. The article proposes the concept of life and creative growth of V.M. Shukshin through the prism of the thesaurus and cluster approach. The explanatory "personal models" for interpreting the biographical text of the writer are clusters of Martin Eden, Hamlet and Stepan Razin. Earlier, biographers and literary critics pointed out the importance of these people for Shukshin, but it was scattered. For the first time, an attempt was made to bring these personal models together into an integral plot of the formation of the writer in the space of culture. At different stages of the writer’s evolution, one of these models dominates, successively replacing each other, but not crowding out, but “overlapping”. The early stage of creativity, focused on Martin Eden’s strategy, is an attempt to “fit in” the current cultural mainstream. This is expressed in following the poetics of socialist realism. The second stage implicitly begins with the rehabilitation of Shukshin’s father in 1956, when the “Hamletian complex” is actualized. It is manifested in a sense of guilt towards his father, the strategy of concealing the true “I”, eccentricities. The third stage is connected with the personality of a real historical person, Stepan Razin, and is expressed in an open protest against the authorities. All important for V.M. Shukshin's behavioral models are united by the motive of a lonely confrontation with a hostile society and have a tragic ending, which led to the early departure of the writer and the generation of myths about the violent nature of his death. V.M. Shukshin was an extraordinary and typical figure at the same time. That allowed his biography to become a “personal model” for subsequent authors who came from the rural outback.

Incorporation of Uridine in Cleavage Stage Eggs of the Sea Urchin Paracentrotus Lividus

1971 ◽  
Vol 26 (8) ◽  
pp. 816-821 ◽  
Author(s):  
Larry E. Bockstahler
Keyword(s):  
Ion Exchange ◽  
Sea Urchin ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Paracentrotus Lividus ◽  
Cleavage Stage ◽  
Early Cleavage ◽  
Cell Stage ◽  
Cleavage Stages ◽  
Layer Chromatography

Incorporation of uridine in cleavage stage eggs of the sea urchin Paracentrotus lividus was investigated. It was shown by ion exchange and thin layer chromatography that most of the uridine taken up during the 16-cell stage was converted into UTP with some incorporation into UDP and UMP. Conversion of uridine to these phosphorylated nucleosides occurred throughout early cleavage stages. A very small amount of uridine taken up by cleavage stage eggs is incorporated into RNA heterogeneous in size. This RNA was examined by polyacrylamide gel electrophoresis.

The encapsular developmental sequence of the mesogastropod Turritella communis (Gastropoda: Turritellidae)

1992 ◽  
Vol 72 (4) ◽  
pp. 783-805 ◽  
Author(s):  
J. J. Kennedy ◽  
B. F. Keegan
Keyword(s):  
Germinal Vesicle ◽  
Average Diameter ◽  
Meiotic Maturation ◽  
Developmental Sequence ◽  
Early Cleavage ◽  
Mantle Tissue ◽  
Cell Stage ◽  
Egg Capsules ◽  
Eupyrene Sperm ◽  
The Right

The development of the lecithotrophic encapsulated larva of the internally-fertilizing, sublittoral gastropod Turritella communis Risso 1826 was documented using scanning electron microscopy and light microscopy. Encapsulated development was completed in 12 days at 15°C in the laboratory. Spawning occurred above ~10°C. Spawn masses consisted of numerous gelatinous egg capsules, each of which contained ~28 eggs, encased in albumen and fertilizing sperm. The eggs had an average diameter of 139 μm. Fertilization was accomplished by unpaired eupyrene sperm and occurred at the germinal vesicle stage. The developmental sequence followed the typical gastropod pattern, but was unique in a number of respects. Polar lobes were produced during meiotic maturation and early cleavage, with an especially large lobe occurring in association with the first cleavage, which was unequal. The blastula developed into a dorso-ventrally flattened placula at the 70-cell stage. Gastrulation occurred through invagination and epiboly acting together, and was uniquely accompanied by the development of ectodermal microvilli measuring ~ 1 μm in length. Extra-embryonic albumen began to be depleted after the development of the microvilli. It is proposed that the ciliated telotrochal cells gave rise to the pair of statocysts. Torsion was additionally observed to be facilitated by the growth of pre-mantle tissue on the right side and retardation of growth on the left side.

scholarly journals Maternal Wnt/STOP signaling promotes cell division during earlyXenopusembryogenesis

2015 ◽  
Vol 112 (18) ◽  
pp. 5732-5737 ◽  
Author(s):  
Ya-Lin Huang ◽  
Zeinab Anvarian ◽  
Gabriele Döderlein ◽  
Sergio P. Acebron ◽  
Christof Niehrs
Keyword(s):  
Wnt Signaling ◽  
Cell Cycle Progression ◽  
Glycogen Synthase ◽  
Effector Proteins ◽  
Glycogen Synthase Kinase 3 ◽  
Dependent Manner ◽  
Early Cleavage ◽  
Cycle Progression ◽  
Midblastula Transition ◽  
Axial Patterning

DuringXenopusdevelopment, Wnt signaling is thought to function first after midblastula transition to regulate axial patterning via β-catenin–mediated transcription. Here, we report that Wnt/glycogen synthase kinase 3 (GSK3) signaling functions posttranscriptionally already in mature oocytes via Wnt/stabilization of proteins (STOP) signaling. Wnt signaling is induced in oocytes after their entry into meiotic metaphase II and declines again upon exit into interphase. Wnt signaling inhibits Gsk3 and thereby protects proteins from polyubiquitination and degradation in mature oocytes. In a protein array screen, we identify a cluster of mitotic effector proteins that are polyubiquitinated in a Gsk3-dependent manner inXenopus. Consequently inhibition of maternal Wnt/STOP signaling, but not β-catenin signaling, leads to early cleavage arrest after fertilization. The results support a novel role for Wnt signaling in cell cycle progression independent of β-catenin.

Specification of anterior-posterior differences within the AB lineage in the C. elegans embryo: a polarising induction

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1559-1568 ◽  
Author(s):  
H. Hutter ◽  
R. Schnabel
Keyword(s):  
Cell Fate ◽  
Tissue Type ◽  
Cell Stage ◽  
Anterior Portion ◽  
Developmental Potential ◽  
C Elegans ◽  
The Third ◽  
Inductive Signal ◽  
Anterior Posterior ◽  
Lineage Analysis

In a C. elegans embryo the third cleavages of descendants of the anterior blastomere AB of the 2-cell stage create pairs of blastomeres that develop differently. By laser ablation experiments we show that the fates of all the posterior daughters of this division depend on an induction occurring three cleavages before these blastomeres are born. The time of induction precludes a direct effect on cell fate. Alternatively, we suggest that the induction creates a heritable cell polarity which is propagated through several divisions. We suggest a model to demonstrate how a signal could be propagated through several rounds of cell division. An important implication of our observations is that this early induction acts to specify blastomere identity, not tissue type. A detailed lineage analysis revealed that altering the inductive signal alters complex lineage patterns as a whole. The induction described here, together with two inductions described previously can be used to illustrate how the anterior portion of the C. elegans embryo can be successively subdivided into blastomeres with unique developmental potential.

Maternal beta-catenin establishes a ‘dorsal signal’ in early Xenopus embryos

Development ◽  
1996 ◽  
Vol 122 (10) ◽  
pp. 2987-2996 ◽  
Author(s):  
C. Wylie ◽  
M. Kofron ◽  
C. Payne ◽  
R. Anderson ◽  
M. Hosobuchi ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Axis Formation ◽  
Beta Catenin ◽  
Cell Stage ◽  
Midblastula Transition ◽  
Xenopus Embryos ◽  
Ability To Act ◽  
Zygotic Transcription ◽  
Spatial Terms ◽  
Marginal Zones

In previous work, we demonstrated that maternally encoded beta-catenin, the vertebrate homolog of armadillo, is required for formation of dorsal axial structures in early Xenopus embryos (Heasman, J., Crawford, A., Goldstone, K., Garner-Hamrick, P., Gumbiner, B., Kintner, C., Yoshida-Noro, C. and Wylie, C. (1994). Cell 79, 791–803). Here we investigated, firstly, the role(s) of beta-catenin in spatial terms, in different regions of the embryo, by injecting beta-catenin mRNA into individual blastomeres of beta-catenin-depleted embryos at the 32 cell stage. The results indicate that beta-catenin can rescue the dorsal axial structures in a non-cell-autonomous way and without changing the fates of the injected cells. This suggests that cells overexpressing beta-catenin send a ‘dorsal signal’ to other cells. This was confirmed by showing that beta-catenin overexpressing animal caps did not cause wild-type caps to form mesoderm, but did cause isolated beta-catenin-deficient marginal zones to form dorsal mesoderm. Furthermore beta-catenin-deficient vegetal masses treated with overexpressing caps regained their ability to act as Nieuwkoop Centers. Secondly, we studied the temporal activity of beta-catenin. We showed that zygotic transcription of beta-catenin starts after the midblastula transition (MBT), but does not rescue dorsal axial structures. We further demonstrated that the vegetal mass does not release a dorsal signal until after the onset of transcription, at the midblastula stage, suggesting that maternal beta-catenin protein is required at or before this time. Thirdly we investigated where, in relationship to other gene products known to be active in axis formation, beta-catenin is placed. We find that BVg1, bFGF, tBR (the truncated form of BMP2/4R), siamois and noggin activities are all downstream of beta-catenin, as shown by the fact that injection of their mRNAs rescues the effect of depleting maternally encoded beta-catenin. Interference with the action of glycogen synthase kinase (GSK), a vertebrate homolog of the Drosophila gene product, zeste white 3 kinase, does not rescue the effect, suggesting that it is upstream.

Urinary nitrogen excretion at the early stage of severe acute pancreatitis

2020 ◽  
Vol 21 (4) ◽  
pp. 131-134
Author(s):  
O. G. Sivkov ◽  
◽  
A. O. Sivkov ◽  
Keyword(s):  
Acute Pancreatitis ◽  
Severe Acute Pancreatitis ◽  
Early Stage ◽  
Ideal Body Weight ◽  
Nitrogen Excretion ◽  
The Third ◽  
Ideal Body ◽  
Urinary Nitrogen Excretion ◽  
Urinary Nitrogen ◽  
The Ideal

Aim. To study urinary nitrogen excretion at the early stage of severe acute pancreatitis. Materials and methods. Prospective, single-center, cohort study. Inclusion criteria: diagnosis of acute pancreatitis and presence of at least one of the predictors of severe course. Among all patients (n = 72), a cohort of patients with severe acute pancreatitis (n = 32) was allocated. Three groups were formed in it: the first one – all patients, the second one – survivors (n = 24), the third one – deceased (n = 8). Urinary nitrogen excretion was determined using the Deacon formula. Measurements were performed on the first, third and fifth days of the disease. Statistical processing of the material was carried out by the SPSS software package. The null hypothesis was rejected at p < 0.05. Results. In the first week of the disease in all groups, the maximum urinary nitrogen excretion occurs on the 3rd day. When comparing the results of the second and third groups, it was found that the urinary nitrogen excretion on the first and fifth days did not have a statistically significant difference between the groups (respectively, p = 0.138, p = 0.572), and the results of the third day have (p = 0.014). A similar pattern remains when recalculating the nitrogen loss in the urine to the ideal weight; for the third day, the differences between the second and third groups were statistically significant (p = 0.007). ROC analysis of urinary nitrogen excretion of the third day calculated to the ideal body weight showed an area under the curve of 0.813 (p < 0.009). The value at the cut-off point is defined as 0.65 g/kg/day. The sensitivity of the model was 0.75%, specificity – 0.83%. Conclusion. If in a patient with acute pancreatitis, there is urinary nitrogen excretion on the third day from the onset of the disease, calculated to an ideal body weight of ≥ 0.65 g/kg/day, an unfavorable outcome of the disease is predicted.

Contribution of maternal factors and cellular interaction to determination of archenteron in the starfish embryo

Development ◽  
1994 ◽  
Vol 120 (9) ◽  
pp. 2619-2628 ◽  
Author(s):  
R. Kuraishi ◽  
L. Osanai
Keyword(s):  
Alkaline Phosphatase ◽  
Normal Development ◽  
Early Stage ◽  
Posterior Part ◽  
Immature Oocyte ◽  
Cellular Interaction ◽  
Cell Stage ◽  
Cytoplasmic Factor ◽  
Animal Pole

Contribution of maternal cytoplasmic factors and cellular interaction to determination of archenteron in a starfish embryo was analyzed by (1) examining temporal and positional pattern of expression of an endoderm-specific enzyme, alkaline phosphatase, (2) deleting the vegetal polar fragment from an immature oocyte and (3) changing the orientation of a blastomere within an early stage embryo. The archenteron (and the differentiated digestive tract) of Asterina pectinifera was divided into three areas based on the time of start of alkaline phosphatase expression. At 27 hours after 1-methyladenine treatment, the whole archenteron except the anterior end started to express alkaline phosphatase. The anterior negative area differentiated into mesodermal tissues such as mesenchyme cells and anterior coelomic pouches (anterior mesodermal area). The alkaline-phosphatase-positive area 1 gave rise to the esophagus and the anterior end of the stomach. Alkaline-phosphatase-positive area 2, which was gradually added to the posterior end of the archenteron after 30 hours, became alkaline-phosphatase- positive and formed the middle-to-posterior part of the stomach and the intestine. When the vegetal oocyte fragment, the volume of which was more than 8% of that of the whole oocyte, was removed from the immature oocyte, archenteron formation was strongly suppressed. However, when the volume deleted was less than 6%, most of the larvae started archenteron formation before the intact controls reached the mesenchyme-migration stage (30 hours). Although cells in the alkaline-phosphatase-positive area 2 are added to the posterior end of the archenteron after 30 hours in normal development (R. Kuraishi and K. Osanai (1992) Biol. Bull. Mar. Biol. Lab., Woods Hole 183, 258–268), few larvae started gastrulation after 30 hours. Estimation of the movement of the oocyte cortex during the early development suggested that the area that inherits the cortex of the 7% area coincides with the combined area of anterior mesodermal area and alkaline-phosphatase-positive area 1. When one of the blastomeres was rotated 180° around the axis of apicobasal polarity at the 2-cell stage to make its vegetal pole face the animal pole of the other blastomere, two archentera formed at the separated vegetal poles. Intracellular injection of tracers showed that cells derived from the animal blastomere, which gives rise to the ectoderm in normal development, stayed in the outer layer until 30 hours; a proportion of them then entered the archenteron gradually. The involuted animal cells expressed alkaline phosphatase and were incorporated into the middle-to-posterior part of the stomach and the intestine. These results suggest that anterior mesodermal area and alkaline-phosphatase-positive area 1 are determined by cytoplasmic factor(s) that had already been localized in their presumptive areas. In contrast, alkaline-phosphatase-positive area 2 becomes the endoderm by homoiogenetic induction from the neighboring area on the vegetal side, namely alkaline-phosphatase-positive area 1.

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