Changes In Synthetic Activity Research Articles

Oviductal regulation of fertilization and early embryonic development

During the period of late follicular development and the first four days of the oestrous cycle, the oviduct occupies a central role in the establishment of pregnancy. Oviductal function is regarded as being either 'passive' or biologically active, providing an environment that sustains and enhances fertilization and early cleavage-stage embryonic development. Recent reports have focused on this microenvironment and shown that ovarian steroids induce marked morphological, physiological and biochemical changes. Alterations include changes in the biosynthetic activity and release of macromolecules by the oviductal epithelium which become part of the luminal microenvironment. Furthermore, both regional and temporal differences in activity and protein production occur through hormonal changes during the oestrous cycle and early pregnancy. Studies on identification, characterization and regulation of several proteins synthesized de novo have indicated oocyte-oviduct and embryo-oviduct interactions. However, the identification of oviduct-derived proteins, their regulation and their potential function in vivo needs to be examined. Studies in other species also suggest roles for growth factors in early embryonic development, but little information is available for the pig. We propose that ovarian hormones control changes in synthetic activity, synthesis of some oviduct-derived proteins and the presence of specific factors in the luminal microenvironment which sustain and enhance fertilization and early cleavage-stage embryonic development.

Donor age affects proteome composition of tenocyte-derived engineered tendon

BackgroundThe concept of tissue engineering is to deliver to the injury site biological scaffolds carrying functional cells that will enhance healing response. The preferred cell source is autologous in order to reduce immune response in the treated individual. However, in elderly patients age-related changes in synthetic activity of the implanted cells and subsequent alterations in tissue protein content may affect therapeutic outcomes. In this study we investigated the effect of donor age on proteome composition of tenocyte-derived tendon tissue-engineered constructs.ResultsLiquid chromatography tandem mass spectrometry was used to assess the proteome of tissue-engineered constructs derived from young and old equine tenocytes. Ageing was associated with altered extracellular matrix composition, especially accumulation of collagens (type I, III and XIV), and lower cytoskeletal turnover. Proteins involved in cell responsiveness to mechanical stimuli and cell-extracellular matrix interaction (calponin 1, palladin, caldesmon 1, cortactin) were affected.ConclusionsThis study demonstrated significant changes in proteome of engineered tendon derived from young and old tenocytes, indicating the impact of donor age on composition of autologous constructs.

Tension-driven axon assembly: a possible mechanism.

As the contents of this issue of “Frontiers” attest, the study of the mechanical aspects of neuronal development has come a long way since the 1970's and 80's when we became interested in the topic. The vast majority of cells in multicellular organisms are continually pushed and pulled, compressed, and stretched throughout their life and a diversity of mechanisms have evolved to protect against and harness these forces. Nerve cells are no exception, and several excellent reviews in recent years have examined ways in which mechanical inputs influence their development and function (Smith, 2009; Suter and Miller, 2011; Franze, 2013). However, it seems to us that certain aspects of this response have not been given the attention they deserve. In particular tension-driven axon assembly seems to be in a class of its own and quite distinct from other effects of tension such as modifications of cell migration, perturbation of division cycles, or changes in synthetic activity. Axon growth under these conditions is an exaggerated transformation of a nerve cell manifest by the prolonged accretion of new cellular material. Under the right circumstances, the rate and extent of this mass addition is remarkably large, to the degree that it implies an unusual, possibly unique mechanism. A pulled axon grows as though the nerve cell contained telescopic machinery prefabricated for elongation. But the identity of this nascent structure (if it exists), where it is stored, and how it is triggered to self-assemble into axon, remain to be discovered.

Effect of estradiol dipropionate on protein synthesis in oocytes and ovary of the sea urchin Strongylocentrotus intermedius at different stages of the reproductive cycle

We studied protein synthesis in the oocytes and ovary of the sea urchin Strongylocentrotus intermedius at different stages of the reproductive cycle after treatment with estradiol dipropionate. During the early development of oocytes and active gametogenesis, this estrogen induced the incorporation of 3H-leucine in the oocytes. The changes in synthetic activity of cells were accompanied by an elevated efficient incorporation of free amino acid in proteins due to its increased pool, increased tissue permeability for precursors, and increased rate of protein synthesis. Before spawning, estradiol dipropionate did not cause any changes in protein synthesis. After estradiol dipropionate treatment, the inhibitors of protein synthesis, puromycin and actinomycin D, decreased the intensity of 3H-leucine incorporation in the oocytes and protein synthesis in the ovary. The involvement of estradiol dipropionate in the regulation of protein synthesis in the sea urchin gonad is discussed.

Age-related changes to the molecular and cellular components of equine flexor tendons.

Specific tendons show a high incidence of partial central core rupture which is preceded by degeneration. In the performance horse, the superficial digital flexor tendon (SDFT) is most often affected. We have described previously the molecular changes that are associated with degeneration in the central core region of the equine SDFT. The pathophysiological mechanism leading to change in synthetic activity of central zone cells in degenerated tendons is not known. In this study, we test the hypothesis that ageing results in matrix composition changes within the central zone of the SDFT. Extracellular matrix composition and cellularity were analysed in equine SDFTs collected from Thoroughbred horses and compared with a flexor tendon which rarely shows degenerative change and subsequent injury (deep digital flexor tendon, DDFT). Data were examined for age-related changes to central and peripheral zone tissue of the SDFT and DDFT. Ageing in both tendons (SDFT and DDFT) resulted in a significant increase in collagen-linked fluorescence and a decrease in cellularity in the DDFT but not the SDFT. The central zone tissue from the SDFT had a significantly higher proportion of type III collagen than the peripheral zone of the tendon. The highest level of type III collagen was found in the central zone tissue of the SDFT from the older group of horses and this may represent the early stages of a degenerative change. Collagen content did not differ between the 2 flexor tendons; however, there were differences in collagen type and organisation. The SDFT had a higher type III collagen content, higher levels of the mature trifunctional collagen crosslink hydroxylysylpyridinoline, lower total chondroitin sulphate equivalent glycosaminoglycan content, smaller diameter collagen fibrils and a higher cellularity than the DDFT. In conclusion, differences in macromolecular composition exist between the flexor tendons and ageing contributes to a tendon specific change in composition.

Effect of continuous darkness on circadian morphological rhythms in pinealocytes of the Chinese hamster, Cricetulus griseus.

Effects of a short-term exposure to continuous darkness on 24-h morphological variations in pinealocytes in the superficial pineal of the Chinese hamster (Cricetulus griseus) were examined. Pinealocytes contained type-1, -2 and -3 synaptic ribbons (SR), which had a central dense structure showing rod-like, various and ring-like profiles, respectively, and the quantity of each type of SR was expressed by SR index. 24-h changes in the type-1 and type-3 SR indices persisted in darkness and thus may be endogenous in nature. As under alternating light and dark (LD) conditions, the type-2 SR indices were almost constant over a 24-h period under continuous darkness, but the indices were larger in animals under darkness than in those under LD conditions. The 24-h variations in the nuclear and cytoplasmic volumes were abolished after exposing animals to darkness for 7 days, suggesting that these rhythms may be regulated exogenously. The amount of condensed chromatin exhibited a circadian change; this rhythm persisted under darkness. The results suggest that 24-h variations in the nuclear and cytoplasmic volumes in pinealocytes of the Chinese hamster are regulated by mechanisms different from those controlling the rhythms in SR and chromatin, and that the changes in the nuclear and cytoplasmic volumes and chromatin are related to the change in synthetic activity of pinealocytes.

Changes in synthetic activity of cell walls during the cell cycle in a synchronous culture of Catharanthus roseus

The incorporation rates of [14C] glucose into various fractions of the cell walls and into the sugar constituent of each fraction were investigated in a synchronous culture of Catharanthus roseus (L.) G. Don in order to elucidate the synthetic aspects of the cell walls during the cell cycle. Changes in the incorporation of radioactivity were closely correlated with changes in the amount of each cell wall fraction as well as with those in sugar composition as reported previously (S. Amino et al. Physiol. Plant. 60: 326–332, 1984). The specific activity of galactose was higher than that of other sugars throughout the cell cycle, and a temporary increase in the incorporation of radioactivity into all cell wall fractions except cellulose was observed just before the increase in cell numbers. The synthetic activities may play key roles in the regulation of cell wall polysaccharide dynamics during the cell cycle.

Changes in synthetic activity of sulfated mucosubstances in healing process of acetic acid ulcer in rats and effect of anti-ulcer agents.

Changes in synthetic activity of sulfated mucosubstances in healing process of acetic acid ulcer in rats and effect of anti-ulcer agents.

Changes in Synthetic Activity of Sulfated Mucosubstances in Healing Process of Acetic Acid Ulcer in Rats and Effect of Anti-Ulcer Agents

Changes in Synthetic Activity of Sulfated Mucosubstances in Healing Process of Acetic Acid Ulcer in Rats and Effect of Anti-Ulcer Agents

The effect of altering the ambient salinity of the freshwater teleost Xiphophorus maculatus on the histophysiology of its prolactin cells : I. Progressive changes in one-third sea water

The platyfish, Xiphophorus maculatus, requires prolactin for survival in its natural fresh-water habitat but can be maintained in dilute sea water if deprived of the hormone. In the current study, males were transferred from fresh water to one-third sea water for periods ranging from 2 hr to 30 days, and several were returned from 30 days in the saline medium to fresh water for up to 72 hr. Progressive cytometric and cytological changes of the prolactin cells were compared with autoradiographic labeling after injections of tritiated leucine. Reduced synthetic activity, as judged by cytologic and autoradiographic evidence, was seen as early as 12 hr after the fish were placed into dilute sea water. A marked reduction in cytoplasmic granulation and cell size was first noted at 48 hr, suggesting that hormonal release was continuing independently of the rate of synthesis during this period. After 30 days, cytometry, cytology, and labeling of the prolactin cells were similar to that observed at 48 hr. There was cytologic and autoradiographic evidence of increased synthetic activity in the prolactin cells by 72 hr after the fish were returned to fresh water from 30 days in one-third sea water. Our observations suggest that there is a reduction in synthesis when platyfish are placed in sea water which can be increased when they are returned to fresh water. These changes in synthetic activity presumably reflect requirements for prolactin in these two environments.

Crystallin synthesis by Chick Lens: II. Changes in synthetic activities of epithelial and fiber cells during embryonic development

Crystallin synthesis by epithelial and fiber cells from 7- to 18-day-old chicken embryo lenses was investigated by cellulose acetate membrane electrophoresis. Epithelial cells of 7- to 12-day-old embryo lenses synthesize mainly δ crystallin and a small amount of α- and β-crystallins; these are all sensitive to actinomycin D (30 μg/ml). As the lens develops from 12 to 18 days, epithelial cells become insensitive to actinomycin D in respect to the synthesis of α- and β-crystallins. At the same time, the synthesis of δ-crystallin ceases. On the other hand, the fiber cell synthesizes primarily δ-crystallin with additional small amounts of α- and β-crystallins; these are all insensitive to actinomycin D during all stages of the development of the lens from 7 to 18 days.

Kern- und Nucleolusausbildung in den Gametophytenzellen von Dryopteris filix-mas (L.) Schott bei Umsteuerung der Morphogenese

The young gametophytes of the fern Dryopteris filix-mas (L.) SCHOTT have different metabolic patterns in red and blue light with blue favouring protein formation. In connection with this, the morphogenesis is also different. Two-dimensional prothallia are developed in blue light; in red light, however, the gametophytes grow as filaments. In the present paper the influence of red and blue radiation upon the size of the nuclei and nucleoli has been studied in fully differentiated stable basal cells and actively dividing apical cells. Time course studies revealed that the apical cell of the red form always contains extremly large nuclei and nucleoli. This is in agreement with high synthetic activity of this cell. In contrast, the apical cells with two cutting faces of the blue grown gametophytes have much smaller nuclei and nucleoli (this may be due to the comparativly high dividing activity of this cells). In already differentiated basal cells, these two organelles are even smaller and show only minor differences between red and blue ones. Within the gametophytes there is a gradient in the nucleus and nucleolus size from the apical to the basal cells. If blue grown gametophytes are brought into red light, or vice versa, typical changes in size of the nucleus and nucleolus in the direction of the respective forms are already visible after 3 hrs. under the new conditions. These changes in size and synthetic activity occur much earlier than any measurable morphological alteration. The data give good evidence for the fact that the striking change in the morphogenesis is preceded by a fundamental change in the synthetic activity of the nucleus and nucleolus.

Control of tissue specificity: the pattern of cellular synthetic activities in tissue transformation.

During transformation of the dorsal marginal iris into lens tissue after removal of the lens in the adult newt, the cells undergo gradual changes in synthetic activities. Autoradiographic data indicate an enhancement of RNA synthesis in the nucleus of iris cells, which is followed by enhancement of protein synthesis and onset ot DNA synthesis. After discharge of pigment granules and a period of cellular multiplication accompanied by ribosome production, the cells stop DNA synthesis and start to show detectable amounts of lens-specific proteins (α-,β-, and γ-crystallins). This time coincides with initiation of differentiation of primary lens fibers. In the later stages of regeneration, α- and β-crystallins are present in the dividing cells of the lens epithelium, as well as in the cells of the fiber area, but γ-crystallins are detected only in Che cells of the fiber area. The data were interpreted as suggesting that the gene utilization pattern typical for the iris is not directly converted into that for the lens, but goes through intermediate patterns before the tissue transformation is completed.