Inclusion of H3-leucine into the mouse mammary gland tissue within various intervals following offspring suckling

In lactating mice, intensity of synthetic processes within different intervals following the suckling cessation, was studied. The study has shown that increasing of the interval following the suckling cessation and the related accumulation of secrete in the alveolas cavities entails diminishing of the H3-leucine inclusion into the tissue and reflects a reduction in intensity of the synthesis processes of the de novo protein molecules in the mammary gland.     

Protein synthesis in abscission: the distinctiveness of the abscission zone and its response to gibberellic Acid and indoleacetic Acid

Abscission zone tissue of citrus was shown to have a higher rate of protein synthesis than tissue distal or proximal to it, based on the incorporation of leucine-1-¹⁴C. The proximal tissue had the slowest rate of protein synthesis. As the tissue approached abscission, the rate of synthesis in the abscission zone decreased and the differences in rate of protein synthesis between the 3 zones almost disappeared. IAA, which delayed abscission, maintained the protein synthesis gradient between the abscission and proximal zones, but the distal zone tissue was as active in protein synthesis as the abscission zone. Differences in uptake of the leucine were also observed between different zones and treatments. Regardless of the tissue or the treatment, there was a sharp increase in uptake at the 24 hour point.

Direct incubation of abscission zones in IAA and gibberellic acid (GA) indicated that the action of gibberellic acid on abscission is probably through a stimulation of protein synthesis, while IAA seems to act by maintaining the existing rate of protein synthesis in the cells of the abscission zone.

     

Diurnal Growth of Tall Fescue Leaf Blades : II. Dry Matter Partitioning and Carbohydrate Metabolism in the Elongation Zone and Adjacent Expanded Tissue

The spatial distributions of net deposition rates of water soluble carbohydrate-free dry matter (WSC-free DM) and WSC were evaluated within and above the elongation zone of tall fescue (Festuca arundinacea Schreb.) leaf blades during light and darkness. Imported DM used for WSC-free DM synthesis during darkness (67% of the total in experiment I and 59% in experiment II) was greater than during light (47% in both experiments), suggesting that the 65% higher leaf elongation rate during darkness was accompanied by higher rates of synthesis of cellular structural components. Deposition rates of WSC in the basal and central part of the elongation zone (0-20 mm from the ligule) were similar during light and darkness, but above 20 millimeters WSC deposition occurred during light and WSC loss occurred during darkness. WSC deposition and loss throughout the elongation zone and the recently expanded tissue were mostly due to net synthesis and degradation of fructan. Fructan was predominantly low molecular weight and contributed about 50% of the total osmotic partial pressure of WSC. In the most actively growing region, where fructan synthesis was most rapid, no diurnal change occurred in molecular weight distribution of fructan. WSC solute concentrations were diluted in the most actively growing tissue during darkness because net monosaccharide and fructan deposition were unaltered and sucrose deposition was decreased, but growth-associated water deposition was increased by 77%. Net rates of fructan synthesis and degradation were not related to tissue sucrose concentration, but appeared to respond to the balance between assimilate import and assimilate use in synthesis of cellular structural components (i.e. WSC-free DM) and deposition of monosaccharides. Fructan synthesized in tissue during most active elongation was degraded when the respective tissue reached the distal limit of the elongation zone where assimilate import in darkness was insufficient to maintain synthetic processes associated with further differentiation of cells.     

Update on the possible mode of action of the jasmonates: Focus on the metabolism of cell wall polysaccharides in relation to growth and development

Jasmonic acid (JA) and its related compounds (jasmonates) applied to plant tissues exert either inhibitory or promotive effects in growth and developmental processes, which in some ways are similar to abscisic acid. However, little is known about the mode of action of the jamonates at the tissue or organ levels. Here, we review partial evidence for the physiological action of the jasmonates on cell elongation and abscission.
Jasmonates inhibit the IAA-induced cell elongation of oat coleoptile segments not by affecting energy production, osmoregulation and cell wall loosening, but by inhibiting the synthesis of cell wall polysaccharides. The inhibition is partially reversed by simultaneous application of sucrose. Inhibition of IAA-induced elongation by JA is only observed in monocotyledons, not in dicotyledons. These effects suggest that jasmonates exert their inhibitory effect on cell elongation by affecting the metabolism of the cell wall polysaccharides in monocotyledons.
Jasmonates promote the abscission of bean petiole explants without enhancing ethylene production. Cells in the petiole adjacent to the abscission zone expand during abscission. In the abscission zone, jasmonates decrease the amount of cellulosic but not that of noncellulosic polysaccharides. Jasmonates increase the activities of cellulase and decrease the levels of UDP-sugars, which are important intermediates for the synthesis of cell wall polysaccharides in the abscission zone, probably resulting in the decreased level of cellulose and the mechanical weakness of cell walls.
Thus, it is suggested that jasmonates exert their multiple physiological effects by affecting the metabolic processes of cell wall polysaccharides.     

Retinoic acid-induced cartilage degradation is caused by cartilage cells

Summary Cartilage cubes, prepared from the proximal epiphyses of neonatal rat humeri and consisting of cartilage tissue only, were cultured in the presence of retinoic acid. The retinoid induced the loss of metachromatic staining with toluidine blue, which correlates with the loss of proteoglycan, followed by tissue degradation processes resulting in a distinct reduction of the cartilage mass. Histologically, fibroblast-like cells appeared within chondrones, indicating a transformation of chondroblasts. Focal tissue degradation was observed after only 2 days. Electron microscopically, the clustered cells within the zone of tissue degradation were rich in various lysosomal structures indicating their lytic activity. Cycloheximide and EDTA completely blocked the retinoic acid effects suggesting that protein synthesis was required and that metalloproteinases may be involved in the degradation processes. In conclusion, with the new test system described here we demonstrated that cartilage cells themselves performed the tissue degradation induced by retinoic acid.     

Changes in the specific cytochemical properties of rat decidual cells during differentiation

The antimesometrial part of rat's decidua of 8-9 day of gestation was divided into three parts: epithelial, transition and basal zones. Cells of either zone have their own morphological and cytochemical features. Cells of the epithelial zone are characterized by synthesis of tissue specific antigens and fat (fatty acids). Cells of the transition zone synthesize glycogen. Acid mucopolysaccharides are located in the basal zone only. Decidual cells do not synthesize cholesterol. Con A receptors are localized on the surface of cells of the basal and transition zones and disappear from the surface of epithelial zone cells. It is concluded that differentiation of large decidual cells of the antimesometrial part of rat's decidua are accompanied by a significant change in cytochemical features of cell precursors the synthesis of acid mucopolysaccharides and glycogen stops, while tissue specific antigens and fat (fatty acids) start their syntheses, Con A receptor disappear.     

The influence of mechanical loading on isolated chondrocytes seeded in agarose constructs

Articular cartilage is subjected to dynamic compressive loading during normal activity which influences chondrocyte metabolism through various mechanotransduction pathways. A well characterised and reproducible model system, involving chondrocytes embedded in agarose gel, has been used to investigate the effects of mechanical compression on chondrocytes, isolated from full depth cartilage or separately from the superficial and deep zone tissue. The role of nitric oxide as a mediator of mechanical-induced effects has also been studied. Chondrocytes were isolated, separately, from full depth, superficial and deep zone cartilage and seeded in 3% agarose constructs. Dynamic compressive strain was applied to the constructs using a range of frequencies (0.3, 1 and 3 Hz). Glycosaminoglycan synthesis, cell proliferation and nitrite production were assessed. In further experiments, constructs were compressed in the presence of 1 mM L-NAME or 10 microM dexamethasone. Glycosaminoglycan synthesis by full depth chondrocytes was affected by compressive strain in a frequency dependent manner. Dynamic strain at all frequencies induced an increase in [3H]-thymidine incorporation. Glycosaminoglycan synthesis by deep zone cells was affected by the strain regimes in a similar fashion to full depth cells, while superficial cells exhibited a similar proliferative response to full depth cells. Dynamic compression inhibited nitrite production, the effect being reversed by L-NAME. Compression induced stimulation of [3H]-TdR incorporation was reversed by L-NAME. These studies demonstrate that glycosaminoglycan synthesis and proliferation are influenced by the dynamic strain regimes in a distinct manner. Indeed the data suggest that these processes occur in different chondrocyte sub-populations. It may be speculated that nitric oxide acts as a mediator of mechanotransduction processes affecting proliferation primarily in the superficial cell sub-population.     

Effect of Protein Synthesis Inhibitors, Auxin, and Gibberellic Acid on Abscission

Chloramphenicol, actinomycin D, and other inhibitors of protein synthesis promote abscission in several plant genera. Abscission is accelerated in species where an abscission layer is present, as well as in tissue where no abscission layer develops prior to abscission. The inhibitors promote abscission in species where cell division is reported to precede the separation processes as well as in tissues where no cell division is associated with the initiation of abscission. Indoleacetic acid (IAA) or auxin precursors, when applied with chloramphenicol and aclinomycin D, overcome the promotive effects of the inhibitors on abscission. These inhibitors apparently do not promote abscission through their effects on auxin precursor conversion, IAA transport, and IAA destruction in the petiole. IAA increases the incorporation of leucine-1-¹⁴C into a trichloroacetic acid precipitable fraction of the abscission zone under conditions where abscission is retarded. A low concentration of IAA which accelerates abscission, decreases incorporation of leucine into protein. Other promoters of abscission — chloramphenicol, d-aspartic acid, and gibberellic acid —also decrease the incorporation of leucine into the protein of the abscission zone. The data indicate that enzymes required for the degradative processes associated with abscission are already present in the abscission zone whereas a continuous synthesis of protein is required for the retention of the leaf.     

Ausmaß und räumliche Verteilung der nucleolären RNS-Synthese in Gewebefragmenten von Riella nach Blockierung der DNS-Synthese

Summary The synthesis of DNA in cells of tissue fragments from the wing of Riella is blocked specifically by treatment with 5-fluorodeoxyuridine. As a consequence of this blockage the nucleoli increase in size to about the 3-fold value of the control and show a higher intensity of staining specific for nucleic acids. Whereas in the control the increase in nucleolar size is restricted to a polar zone of the fragment, it spreads out over the fragment under the influence of FUDR.     

Lipid peroxidation and Ca2+,Mg2+-ATPase activity of uterine myocyte cell membranes in hyperplastic processes

It was shown that intensity of endogenous, Feascorbic- and NADPH-dependent lipids peroxidation in the border zone was 2-2.5-fold as higher as in the normal tissues. In the central part of the knot the intensity of all these above mentioned forms of lipids peroxidations is much lower than in the normal tissue. Plasma membrane Ca2+, Mg(2+)-ATPase activity of the border zone of myomic knot is 2-fold as lower as in the normal tissue. 10(-6) M malonal dialdegide decreases the Ca2+, Mg(2+)-ATPase activity up to the level of this enzyme activity in the border zone of myoma knot.     

DNA biosynthesis in the muscular and connective tissue cells of the heart in experimental myocardial infarct

In 60 rabbits with experimental myocardial infarction induces by ligation of the anterior branch of the left coronary artery, DNA synthesis was studied by means of H3-thymidine in muscular and connective tissue cells depending on the period of myocardial infarction. The development of myocardial infarction in the cardiac muscle was stated to be accompanied by activation of DNA synthesis in the connective tissue cells not only in the necrotic zone but in the adjacent, as well as in distant areas of the myocardium and in stromal cells of the auriculum. Indices of H3-thymidine labeled nuclei were of high value during the acute period of myocardial infarction and gradually decreased with the time elapsed since the operation. During the period of the myocardical infarction organization high activity in DNA synthesis was revealed in connective tissue elements of the epicardium and the subepicardial zone of the heart. Myocardial cells of the cardiac auriculi incorporated H3-thymidine but extremely seldom-single labels per thousands of nuclei. In the auriculi with application of prolonged sessions of the labeled precussor introduction, DNA synthesising nuclei were revealed, sometimes with paired nuclei of cardiomyocytes.     

Histochemical study of matrical components in the mandibular condyle of the neonatal mouse

In the mandibular condyle of the newborn mouse the chondroprogenitor (CP) zone is the only layer that incorporates 3H-thymidine thus serving the source for cells of the cartilage lineage. Ultrastructurally these cells have a mesenchymal appearance surrounded by collagen fibrils as well as by additional filaments that become apparent following fixation with ferrocyanide-reduced OsO4. In addition, electron-dense particles indicative of proteoglycans are scattered throughout the matrix in the CP zone as well as in the chondroblastic and hypertrophic zones. Following labeling with 35S-sulfate the CP zone as well as the other compartments revealed a substantial number of grains following processing for autoradiography. The number of grains per cell was highest in the hypertrophic zone. Indirect immunofluorescence indicated the presence of fibronectin in the articular surface, CP zone and in the hypertrophic zone. The immunogold method localized fibronectin intracellularly in CP cells and extracellularly in the hypertrophic zone. Therefore, in the mandibular condyle the CP cells which are capable for DNA synthesis are also involved in the synthesis of macromolecules of which some are specific for the cartilage phenotype, while others are associated with other functions of connective tissue cells.     

Effect of tageflar, a synthetic analog of L-enkephalin, on the morphogenesis of experimental pancreatitis

It has been substantiated that the use of a new synthetic drug tageflar analogous to L-enkephalin was accompanied by the depression in pancreatic enzyme activity in the blood of rats, acceleration of necrotic and lytic processes in irreversibly damaged exocrine pancreocytes in the course of experimental pancreatitis. The drug promoted microcirculation retention in the injury zone and acceleration of the arrangement and elimination of necrotic glandular tissue. The influence of tagaflar diminished the extent of perifocal necrobiotic zone and suppressed sclerotic processes and pancreatic lipomatosis.     

The Pattern of Protein Synthesis in Acetabularia mediterranea

In cells of Acerabularia mediterranea Lamouroux the zone ofgrowth and differentiation is restricted to the approximately2 mm-long outermost apical region of the cylindrical stalk.Protein synthesis along the cell forms a pattern with two statesof intensity corresponding to the growing and the non-growingzone. An identical two-step pattern is obtained when cytoplasmicprotein synthesis is inhibited with D-MDMP, which suggests thatorganellar synthesis on 70S ribosomes contributes to the unevenintensity. The gradient is eliminated by amputation of the apicalall part, and it is re-established concomitant with the emergenceof a new growth zone. Protein synthesis on 80S ribosomes isa pre-requisite for the re-establishment. A two-step patternexists also in anucleate cells persisting for at least 2 weekspost-enucleation. Acetabularia, gradient, morphogenesis, polarity, protein synthesis     

Chondrocyte differentiation and bone growth during the development of the cartilaginous skeleton of chickens]

Certain local alterations in functional and reproductive activity of chondrocytes were stated at the development of the cartilage skeleton. In epiphyses chondrocytes gradually pass into the phase of rest (G0) with subsequent multiplication during the process of skeletal development. In these structures biosynthesis of nonsulfated proteoglycans predominate, in time, while in other cartilage zones--that of sulfated ones. Proofs are furnished on gradual transition of epiphyseal chondrocytes into the state peculiar for cells of the proliferative zone accompanied by an intensified biosynthesis of sulfated proteoglycans and collagenous proteins. Owing to these peculiarities they can be compared with the cells of the reserve zone in the mammalian metaepiphyseal cartilage. It was stated that intensity of chondrogenesis and growth of bones are affected by several processes: intensity of chondrocyte multiplication, the rate of their repeated division in the proliferative zone, the velosity with which the cells transfer into the state of hypertrophy and the rate of the periostal bone formation at the border-line of metaphysis and diaphysis.     

Regional features of the cellular composition of different zones of lymph nodes in the adult human

The amount of plasma cells is connected with intensity of humoral immunological reactions. In people died an accidental death, the amount of immature plasma cells is the least in the axillary and the greatest--in the mesenteric nodes, especially in the thymus-independent zone. The amount of lymphoblasts and large lymphocytes, reflecting intensity of the humoral and cellular immune reactions, is also the greatest in the mesenteric lymph nodes, both in the thymus-dependent and in the thymus-independent zone. In all probability, the intensity of the immunological processes is minimal in the axillary, it is middle in the iliac and cervical and it is maximal in the mesenteric lymph nodes. In each case it is probably connected with peculiarities of antigenic composition of the lymph inflow. The mesenteric lymph nodes are on the way of the foreign protein getting into the intestine. This is evidently reflected by the highest content of immature plasma cells, lymphoblasts and large lymphocytes in them.     

A Role for the Stele in Intertissue Signaling in the Initiation of Abscission in Bean Leaves (Phaseolus vulgaris L.)

A combination of microdissection and viscometric endo-[beta]-1,4-glucanhydrolase assays was used to investigate if the early appearance of the abscission-related isoelectric point-9.5 endo-[beta]-1,4-glucanhydrolase in the stele of the pulvinus and abscission zone of the foliar abscission zone of Phaseolus vulgaris L. prior to cell separation (reported by E. del Campillo, P.D. Reid, R. Sexton, L.N.Lewis [1990] Plant Cell 2: 245-254) indicates that the vascular tissue of this region has a specific role in abscission. We find that no endo-[beta]-1,4-glucanhydrolase activity or cell separation is detectable in the abscission zone cortex if the abscission zone cortex is separated from the stele tissue. If the stele is separated from the abscission zone cortex after a lag period but again before any endo-[beta]-1,4-glucanhydrolase activity is present in the abscission zone cortex, then the enzyme is produced in the cortex and abscission ensues. We conclude that the cortex of the abscission zone is able to abscind independently of the vascular tissue only after the vascular tissue has begun to respond to abscission-promoting signals. We suggest that ethylene promotes formation of an abscission-permitting signal in the stele of the abscission zone and pulvinus, and that this signal is an essential elicitor for the synthesis of cell separation enzymes in the target cells of the abscission zone cortex.     

Effect of adrenaline on the activity of lipolytic enzymes in calves

The research of adrenalin influence on the lipid synthesis and split intensity and fat acid oxidation was carried out in two groups of one-month old calves of black-white breed. The animals were injected by adrenalin (1 mg/kg) during 3 days. The specimens of the musculus quadriceps extensor femoris were used for biochemical researches. The increase of the triacylglycerol lipase activity and oxidation intensity of [1-14C] palmitic and [1-14C] stearic acids and the reduction of lipoprotein lipase activity and lipid synthesis from acetic acid intensity were found during researches. So, the reciprocal dependence between lipid synthesis and fatty acid oxidation as well as the connection between processes of lipolysis and fatty acid beta-oxidation, influenced by adrenalin, were observed in the skeletal muscles of the cattle.     

Variability of enzyme systems in the coenopopulation of Taraxacum officinale s.l. from the zone of East-Ural- radioactive trace

Levels of soil contamination with 90Sr and 137Cs radionuclides on the plots within the zone of Eastern-Ural radioactive trace exceed values of the global level 4-240 times. We have carried out allozyme analysis of apomict species Taraxacum officinale s.l. from this zone. Zimogrammes were interpreted as allozyme phenotypes. In condition of chronic irradiation the plants had increased phenogenetic variability of majority enzymes systems and high frequency of rare morphs. Thus, in plant coenopopoulations situated in radioactive-polluted zone, genomic recombination processes show higher intensity. High enzymatic variability provides the material for natural selection and increase the adaptive potential of coenopopulations.