Successive Developmental Stages Research Articles

Ultra structural study of the Embryonic Development in the Intrauterine Eggs of Acanthostomum (atrophocaecum) aswaninesis Wannas, 1977 (Digenea, Acanthostomatidae) with evidence of early miracidium development

Intrauterine embryonic development of the eggs of Acanthostomum (atrophocaecum) aswaninesis was investigated by transmission electron microscopy. The study revealed the successive stages of embryonic development of the eggs. The proximal uterus contains unembryonated eggs and eggs with early embryos while the distal regions of the uterus were occupied with eggs containing fully developed embryos, each was composed of a fertilized oocyte and few vitelline cells; which were fused forming the vitelline syncytium that characterized the early embryonated eggs. With egg development, the eggshell progressively thickened with the appearance of the operculum after shell formation at the narrower pole of the eggshell surface. Three types of differentiated blastomeres are formed as a result of the continued cleavage divisions; macromeres, mesomeres and micromeres, with nuclei of different shapes and sizes. They occupy different places within the embryo. As a result of the following cleavage divisions, early degeneration or apoptosis of some micromeres take place. Numerous fully developed cilia are easily visible around the differentiated embryo (miracidium) of the advanced stages. The cilia have a typical 9+2 (nine peripheral and two central) arrangement of microtubules. The germinative cells of miracidia have easily appeared in the medioposterior parts of their ciliated larvae. The results of the present study were compared with those previously reported for other parasitic Platyhelminthes.

Effects of endogenous abscisic acid on fruit growth and ripening of coloured capsicum (Capsicum annuum)

The present study was conducted at ICAR-IARI, New Delhi in the year 2016–17 to ascertain the role of abscisic acid (ABA) on fruit growth and ripening in capsicum. ABA was estimated at five fruit developmental stages of yellow and red coloured varieties. Irrespective of varieties higher level of ABA was recorded at 1st stage which later on showed slight reduction at 2nd and 3rd stages and thereafter, registered further sharp rise at 4th stage. Respiration rate was higher in earlier stages and later it decreased up to two fold in fifth stage. Total chlorophyll was reduced in successive developmental stages while carotenoid increased. Total carotenoid content was found to be ABA dependent and it increased with elevation in fruit's ABA content. The results indicated that ABA plays a vital role not only in fruit ripening but in early fruit growth of capsicum too.

The transcription factor TCF-1 enforces commitment to the innate lymphoid cell lineage.

Innate lymphoid cells (ILCs) play important functions in immunity and tissue homeostasis, but their development is poorly understood. Through the use of single-cell approaches, we examined the transcriptional and functional heterogeneity of ILC progenitors and studied the precursor–product relationships that linked the subsets identified. This analysis identified two successive stages of ILC development within TCF-1+ early innate lymphoid progenitors (EILPs), which we named ‘specified EILPs’ and ‘committed EILPs’. Specified EILPs generated dendritic cells, whereas this potential was greatly decreased in committed EILP. TCF-1 was dispensable for the generation of specified EILPs, but required for the generation of committed EILPs. TCF-1 used a pre-existing regulatory landscape established in upstream lymphoid precursors to bind chromatin in EILPs. Our results provide insight into the mechanisms by which TCF-1 promotes developmental progression of ILC precursors, while constraining their dendritic cell lineage potential and enforcing commitment to ILC fate.

Time to Fight: Molecular Mechanisms of Age-Related Resistance.

Plant age is a crucial factor in determining the outcome of a host-pathogen interaction. In successive developmental stages throughout their life cycles, plants face dynamic changes in biotic and abiotic conditions that create distinct ecological niches for host-pathogen interactions. As an adaptive strategy, plants have evolved intrinsic regulatory networks that integrate developmental signals with those from pathogen perception and defense activation. As a result, amplitude and timing of defense responses are optimized, so as to balance the cost and benefit of immunity activation. A general term "age-related resistance" refers to a gain of disease resistance against a certain pathogen when plants reach a relatively mature stage. Age-related resistance is a common observation on fruits, vegetables, and row crops for their resistance against viruses, bacteria, fungi, oomycetes pathogens, and insects. This review focuses on the recent advances in understanding the molecular mechanisms of how plants coordinate developmental timing and immune response.

Architectural design for optimised performance supported by aerospace Value Assessment methods

This paper focuses on novel interdisciplinary design methodologies between architecture and aerospace engineering in support of drastic required changes for the construction of genuinely resilient and sustainable buildings. Current design and construction methods are rarely truly interdisciplinary; driven by successive development stages as opposed to holistic system views capable of integrating valuable feedback loops into the design process and whole life cycle stages of a building. We address these deficiencies by integrating two methods that have been successfully tested independently. Firstly, the “Virtual Design Studio” (VDS) approach that focuses on holistic architectural design processes, initially funded by the US Department of Energy at Syracuse University and the New York State Center of Excellence for Energy and Environmental Systems. Secondly, the Value Assessment (VA) methodology supported by Visual Analytics in aerospace engineering design cycles, initially funded by the European Commission FP7 through the TOICA project and currently funded by Innovate UK through the APROCONE project, and developed by the Engineering Design Centre at the University of Cambridge.

TIME- SPACE CONTINUUM IN GEORGIAN ROMANTIC POETRY GÜRCÜ ROMANTİK ŞİİRLERİNDE MEKAN VE ZAMAN ПРОСТРАНСТВЕННО-ВРЕМЕННОЙ КОНТИНУУМ В ГРУЗИНСКОЙ РОМАНТИЧЕСКОЙ ПОЭЗИИ

The represented paper concerns how the time-space chronotope is reflected in the Georgian romantic era poetry. The issue is discussed basing on the writings of the Georgian romantic era poets: Al. Chavchavadze, Gr. Orbeliani and Nikoloz Baratashvili. Special attention is paid to perceiving three main dimensions of time: past, present and future, on the beginning stage and successive stages of development of the Romantic Movement in literature. Parallel to conceptual (objective) apprehension of the time-space phenomenon, there is a perceptual (artistic) time and space notions as resulted from the artistic imagination. The imagination takes its important place in Georgian romantic poetry though it should be noted that on the first and second stages of the romantic poetry development perception of the time-space chronotope was mainly conceptual. Empiric time-space correlation, idealization of the past, and its vision in the future represented the basic inspiration for their poetry. Their poetry stays within the social way of life. Artistic concept of time and space is compressed implying only the real life. Past is reflected through personal memories and is connected to the future only by means of poetic imagination in which it can be realized. In their poetry time and space are narrow and confined, resolved only within two dimensions – present and past. Future is shown only as against the past background. Past is acceptable and it can be transferred to desirable future. On the final stage of romantic era (N.Baratashvili) the time-space chronotope is described differently. In Nicoloz Baratshvilis’s poetry the concepts of time and space are vast and diversified. Time is reflected in his poetry conceptually as well as perceptually. When studying Baratashvilis’s poetry it is very important to pay attention to coexistence of such phenomena as time and something beyond time, space and something above-spatial. His poetry involves both our world and whole universe; heavens as space are represented side by side with worldly space which is very important aspect when studying his poetry.

Neurath’s boat and the Sally-Anne test: Life, Cognition, Matter and Stuff

Making sense of the world around us is likened to the task of staying afloat on a stormy sea while rebuilding our craft of ideas and concepts as we go. This metaphor is pursued through successive stages of cognitive development, and more sophisticated appreciation of multiple perspectives; from pre-theoretical to folk science to the theoretical, from individual to social to inter-subjective agreement. This inescapably generates reflections on the relationships between embodied and situated Life and Cognition.

Using a Multi-Stage hESC Model to Characterize BDE-47 Toxicity During Neurogenesis.

Although the ramifications associated with polybrominated diphenyl ethers (PBDEs) exposures during human pregnancy have yet to be determined, increasing evidence in humans and animal models suggests that these compounds cause neurodevelopmental toxicity. Human embryonic stem cells (hESCs) models can be used to study the effects of environmental chemicals throughout the successive stages of neuronal development. Here, using a hESC differentiation model, we investigated the effects of common PBDE congeners (BDE-47 or -99) on the successive stages of early neuronal development. First, we determined the points of vulnerability to PBDEs across 4 stages of in vitro neural development by using assays to assess for cytotoxicity. Differentiated neural progenitors were identified to be more sensitive to PBDEs than their less differentiated counterparts. In follow-up investigations, we observed BDE-47 to inhibit functional processes critical for neurogenesis (eg, proliferation, expansion) in hESC-derived neural precursor cells (NPCs) at sub-lethal concentrations. Finally, to determine the mechanism(s) underlying PBDE-toxicity, we conducted global transcriptomic and methylomic analyses of BDE-47. We identified 589 genes to be differentially expressed due to BDE-47 exposure, including molecules involved in oxidative stress mediation, cell cycle, hormone signaling, steroid metabolism, and neurodevelopmental pathways. In parallel analyses, we identified a broad significant increase in CpG methylation. In summary our results suggest, on a cellular level, PBDEs induce human neurodevelopmental toxicity in a concentration-dependent manner and sensitivity to these compounds is dependent on the developmental stage of exposure. Proposed mRNA and methylomic perturbations may underlie toxicity in early embryonic neuronal populations.

Erosive Response of Non-Glaciated Pyrenean Headwater Catchments to the Last Major Climate Transition and Establishing Interglacial Conditions

Non-glaciated mountain headwater catchments feature high-resolution geomorphic archives, which provide important insight into erosive processes and sediment dynamics in mountain ranges. As such the Valle de la Fueva catchments in the southern Pyrenees present high-lying talus remnants, extensive denudation surfaces (pediments), deeply incised tributary ravines, and low-lying fluvial-cut terraces. Based on geomorphic analyses and absolute dating using terrestrial cosmogenic nuclides and optically stimulated luminescence, a (late stage) catchment erosion model for the Valle de la Fueva was elaborated and indicates successive development stages of (i) lasting pedimentation under cold-climate conditions during Marine Isotope Stages 4–2, (ii) rapid fluvial dissection, sediment remobilization and downcutting of ravines in response to the last major climate transition and establishing interglacial conditions, and (iii) late stage fluvial incision after 3–4 ka due to regionally increased flood magnitudes, and/or intensification of agriculture and forest management. Valle de la Fueva headwater catchment analysis indicated that the styles and magnitudes of basin surface processes were directly correlated with the amplitude and nature of paleoclimatic changes, modified by the interplay of environmental parameters. In contrast to large-scale fluvial systems, mountain headwater catchments seemed to be less afflicted with temporal and spatial averaging biases. They are thus useful targets for investigating direct climate change effects, surface process coupling, and non-linear response mechanisms in Quaternary fluvial systems.

The complexity of the Fragaria x ananassa (octoploid) transcriptome by single-molecule long-read sequencing

Strawberry (Fragaria x ananassa) is an allopolyploid species with diverse and complex transcripts. The regulatory mechanisms of fruit development and maturation have been extensively studied; however, little is known about the signaling mechanisms that direct this process in octoploid strawberry (Fragaria x ananassa). Here, we used long-read sequencing (LRS) technology and RNA-seq analysis to investigate the diversity and complexity of the polyploid transcriptome and differentially expressed transcripts along four successive fruit developmental stages of cultivated strawberry. We obtained a reference transcriptome with 119,897 unique full-length isoforms, including 2017 new isoforms and 2510 long noncoding RNAs. Based on the genome of the plausible progenitor (Fragaria vesca), 20,229 alternative splicing (AS) events were identified. Using this transcriptome, we found 17,485 differentially expressed transcripts during strawberry fruit development, including 527 transcription factors (TFs) belonging to 41 families. The expression profiles of all members of the auxin, ABA pathway, and anthocyanin biosynthesis gene families were also examined, and many of them were highly expressed at the ripe fruit stage, strongly indicating that the role of those genes is in the regulation of fruit ripening. We produce a high-quality reference transcriptome for octoploid strawberry, including much of the full-length transcript diversity, to help understand the regulatory mechanisms of fruit development and maturation of polyploid species, particularly via elucidation of the biochemical pathways involved in auxin, ABA, and anthocyanin biosynthesis.

Historical Narratives of Women’s Contributions to Education in Northern Nigeria

From time immemorial, women have made tremendous contributions to the development of their respective societies. These vary greatly with each successive stage of human development. Northern Nigeria is patriarchal in nature which is a major feature of a traditional society where powerful cultural traditions undermine the rights of women. They are therefore discriminated upon from, in most cases, acquiring formal education. Girl’s educational opportunities tend to be circumscribed by patriarchy, parent’s preference of education of boys than girls. In spite of the social pressures on women such as early marriage, and other extraneous factors as well as practices, many women are breaking glass ceiling and contributed greatly in educational development in Northern Nigeria. This paper used a historical analysis to discuss women’s contributions to education. The paper examined these contributions in tripartite structures: Pre-colonial, Colonial and Post-colonial and argued that Nana Asma’u bin Fodio’s scholarly position and intellectual contributions to the development of women education were the major factors for the solid foundation of women education.Key words: Northern Nigeria, Women, Education, Pre-colonial, Colonial, Post-colonial

Laser, Universe and Arrow of Time

We have presented a comparison between the universe and the Laser. In many ways, the physics of laser and the universe are analogous. The root of the analogy is the fact that both laser and early universe depend completely on the quantum nature. We have also presented a simple analogous example of the growth of a flower at successive stages of development and shown how the arrow of time may be represented in these cases.

Shrimps and leaves: Phytodetrital pulses and bioturbation in deposits of a river-dominated delta (Middle Jurassic Lajas Formation, Neuquén Basin, Argentina)

The Middle Jurassic Lajas Formation of the Neuquén Basin (Argentina) records mainly deltaic sedimentation. However, the precise role of the depositional mechanisms involved is still controversial. Well core YPF Nq. Laj-8 records the overall vertical transition from delta-front mouth bars to delta plain. Discrete mouth-bar successions typically comprise a lower unbioturbated sandstone unit that passes upwards into a more intensely bioturbated sandstone unit. Phytodetrital material is abundant through the mouth-bar succession forming distinct layers in the lower units and becoming part of the lining of the burrow walls of Ophiomorpha irregulaire and Gyrolithes isp. in the upper units, representing two successive developmental stages of deltaic sandy mouth bars. Layers rich in phytodetritus exhibiting the same characteristics have been traditionally interpreted in outcrop as mudstone drapes generated by tidal action during slack-water periods. However, more recent research suggests that these layers can be best regarded as produced by river-fed flows, which is consistent with a river-dominated delta model.

Morphological features of the yolk processing pattern in the eastern fence lizard, Sceloporus undulatus (Phrynosomatidae).

Features of embryonic development in birds traditionally have been assumed to be shared by sauropsids in general. Herein, we document a pattern of yolk processing and cellularization in the Eastern fence lizard (Sceloporus undulatus) that is fundamentally different from that of birds. In the avian pattern, cells of the yolk sac lining phagocytose, and digest yolk material. These cells release products of digestion into underlying blood vessels for transport back to the embryo. In contrast, microscopic examination of the developing eggs of S. undulatus reveals that the yolk mass is converted into vascularized, "spaghetti-like" strands that fill the yolk sac cavity. Three successive developmental stages are involved. First, the liquid yolk is invaded by proliferating endodermal cells, which phagocytose and digest the yolk material. These cells form clumps that progressively fill the yolk sac cavity. Second, small blood vessels derived from the yolk sac vasculature invade the yolk sac cavity. Third, the endodermal cells become organized in monolayers around these vessels. This arrangement provides a means by which large numbers of endodermal cells can digest yolk, with each cell being positioned to release products of digestion into an adjacent blood vessel for transport to the embryo. The mechanism of yolk processing in this lizard species is similar to that of recently studied snakes. From its phylogenetic distribution, we infer that this pattern probably is ancestral for squamate sauropsids.

Somatic embryogenesis from stem thin cell layers of Dendrobium aqueum

An efficient in vitro regeneration protocol through somatic embryogenesis was established from stem transverse thin cell layers (tTCLs) of Dendrobium aqueum Lindley, an imperiled orchid. This study outlines the induction and successive maturation stages of D. aqueum somatic embryos (SEs). The tTCLs (~ 0.5 mm thick) cultured on halfstrength Murashige and Skoog (MS) medium containing cytokinins and auxins, either individually or in combination, produced embryogenic callus (EC). Treatment with 0.5 mg dm-3 zeatin induced EC in 41.42 % of tTCLs. As many as 42.66 globular SEs per tTCL were formed in the presence of 1.5 mg dm-3N6-(2-isopentyl) adenine (2iP) but only on 10.33 % of explants. The combined treatment of 2iP (1.5 mg dm-3) and 0.5 mg dm-3 6-benzyladenine resulted in 34 globular SEs on 14.7 % of tTCLs whereas the combination of 2iP and 1.0 mg dm-3 indole-3-butyric acid (IBA) induced 7.4 globular SEs on 52.33 % of tTCLs. Supplementation of activated charcoal, amino acids, and antioxidants alleviated browning at all the concentrations tested, but the EC response declined. The addition of 0.5 mg dm-3 polyvinylpyrrolidone to 1.5 mg dm-3 2iP and 1.0 mg dm-3 IBA produced 24 SEs on 19.89 % of tTCLs suggesting that the EC and SEs can be effectively induced by individual cytokinins whereas the synergistic treatments with other compounds can only enhance the induction of EC. Histological observations of EC showed the formation of globular SEs from sub-epidermal regions. Successive developmental stages of globular SEs and the intermediate stage of protocorm like bodies until the formation of plantlets were observed. The plantlets obtained through SEs showed no morphological variations, and inter simple sequence repeat profiles also confirmed the genetic fidelity of in vitro-derived progeny with high monomorphism (97.78 %). In conclusion, the use of stem tTCLs is an effective method to produce SEs through indirect somatic embryogenesis in D. aqueum.

Design of reliability critical system using axiomatic design with FMECA

In product design, the initial design stage is being increasingly emphasized because it significantly influences the successive product development and production stages. However, for larger and more complex products, it is very difficult to accurately predict product reliability in the initial design stage. Various design methodologies have been proposed to resolve this issue, but maintaining reliability while exploring design alternatives is yet to be achieved. Therefore, this paper proposes a methodology for conceptual design considering reliability issues that may arise in the successive detailed design stages. The methodology integrates the independency of axiomatic design and the hierarchical structure of failure mode, effects, and criticality analysis (FMECA), which is a technique widely used to analyze product reliability. We applied the proposed methodology to a liquefied natural gas fuel gas supply system to verify its effectiveness in the reliability improvement of the design process.

Dynamic changes in insoluble polysaccharides and neutral lipids in the developing anthers of an endangered plant species, Pancratium maritimum

Dynamic changes in the distribution of lipid and insoluble polysaccharide reserves of Pancratium maritimum L. (Amaryllidaceae) anthers were investigated throughout the successive stages of pollen development, using cytochemical methods, to determine whether the synthesis, transformation, and mobilization of reserve materials in developing anthers follow the regular pathway in angiosperms and support the physiological activities in developing pollen. Polysaccharides and lipid reserves exhibited a variable pattern of distribution from the sporogenous cell stage to the anthesis. Starch granules and lipid bodies were scarce in the cytoplasm of sporogenous cells, but their number increased significantly at the premeiotic stage. Conversely, starch and lipid reserves of meiocytes reduced at the early prophase of the first meiotic division, and then their amount showed fluctuations during the microsporogenesis. The cytoplasm of free and vacuolated microspores was poor regarding the polysaccharide and lipid reserves. However, at the late vacuolated microspore stage, small insoluble polysaccharides began to appear in the microspore cytoplasm, and their number increased remarkably in the cytoplasm of the bicellular pollen grain. During the maturation of pollen grains, polysaccharide reserves were replaced with lipids. The starch and lipid reserves of the staminal envelope also showed variations at different stages of the anther development. The dynamic changes in the polysaccharide and lipid reserves of P. maritimum anthers were consistent with the physiological activities such as differentiation, cell division and material synthesis that occur in the anther tissue at different stages of the male gametophyte development, and supported the normal pollen development.

Regional Fish-Based Biostratigraphy of the Late Neogene and Pleistocene of Southeastern Europe

Abstract This paper presents analytical results of the study of numerous freshwater fish fossils from almost 40 localities in the territory of southeastern Europe. It has been established that freshwater fishes can be regarded as parastratigraphic group suitable for biostratigraphic studies. Ten ichthyofaunal assemblages have been distinguished and characterized in the paper. These assemblages represent successive developmental stages in freshwater fish communities within southeastern Europe during the late Miocene, Pliocene and Pleistocene. Indices of evolutionary transformations (extinction rate, origination rate, taxonomic rotation) for ichthyofaunal assemblages have been calculated, and their trend is discussed herein.

AN OVERVIEW OF POLLEN AND ANTHER WALL DEVELOPMENT IN Catalpa bignonioides WALTER (BIGNONIACEAE)

Anther development in Catalpa bignonioides Walter was investigated from the sporogenous cell to the mature pollen grain stages to determine whether the pollen and anther wall development follows the basic scheme in angiosperms. In order to follow pollen ontogeny through successive stages of pollen development, anthers at different developmental stages were embedded in epon according to the usual method, and semi-thin sections, taken from the epon embedded anthers, were stained with toluidine blue for general histological observations under light microscopy. The young anther wall of C. bignonioides consists of four layers; from the exterior, the epidermis, endothecium, middle layer, and a secretory tapetum. The tapetum is dual in origin and dimorphic. Ubisch bodies were observed on the inner tangential walls of the tapetal cells. The number of the anther wall layers changes depending on the developmental stage and region of the anther. In contrast to the other anther wall layers , epidermis and endothecium layers remain intact until anthesis. Endothecial cells enlarge and develop thickenings at maturity. During microspore development , meiocytes undergo meiosis and simultaneous cytokinesis leading to the formation of permanent tetrahedral, isobilateral and rarely linear tetrads. Pollen tetrads are shed from the anther as compound pollen grains. Results of the study revealed that pollen and anther wall development in C. bignonioides follows the basic scheme in angiosperms.

Auxin Response Dynamics During Wild-Type and entire Flower Development in Tomato.

The plant hormone auxin is a major regulator of plant development and response to environmental cues. Auxin plays a particularly central role in flower development, but the knowledge of its role of flower development in crop plants with fleshy fruits, such as tomato, is still scarce. Mutations in the Aux/IAA gene ENTIRE/Indole Acetic Acid 9 (E/IAA9) lead to the precocious development of young gynoecia into parthenocarpic fruits. Here, we compared the distribution of the auxin response sensor DR5::VENUS and the auxin efflux transporter PIN1 between the wild type and entire during successive stages of flower and fruit development. Up-regulation of the DR5::VENUS signal in the shoot apical meristem (SAM) was observed upon the transition to flowering, implicating a possible role for auxin in the transition from a vegetative SAM into an inflorescence meristem. DR5::VENUS was expressed in all initiating floral organs. Additionally, DR5::VENUS was highly expressed during gametogenesis, in both male and female organs, and in the developing seeds during embryogenesis. DR5::VENUS is expressed in functional cell layers such as the anther stomium and tapetum, suggesting that auxin plays a role in flower organ development and function. The entire mutation affected DR5::VENUS expression patterns during inflorescence formation and flower organ development, which correlated with phenotypic alterations. We also show dynamic distribution and localization of the auxin transporter PIN1 during flower and fruit organ development. These results emphasize the dynamic auxin response in inflorescence and flower development and suggest multiple roles of auxin in these processes.