Developmental Changes In Activity Research Articles

Changes in Tryptophan Hydroxylase 2 and 5HT1A Receptor Density May Contribute to Developmental Variation in Response to Serotonin in the in vitro Bullfrog Brainstem

Bullfrog, Lithobates catesbeiana, is a vertebrate animal model that can be used to study toxicology and developmental physiology. Our research is focused on better understanding vulnerability to brainstem respiratory centers in the pathology of sudden infant death syndrome (SIDS). We propose that a link between nicotine exposure during development leads to changes in the serotonergic signaling cascades of respiratory coordinating neurons. Caudal raphe neurons send serotonergic fibers that arborize and terminate directly on or near respiratory neurons in the brainstem. In bullfrogs, serotonin elicits a developmentally dependent effect on respiratory motor output. Late metamorphic tadpoles demonstrate an increase in lung burst activity with exposure to low concentrations of serotonin (≤ 0.5μM 5-hydroxytryptamine; 5-HT) mediated in part by 5-HT1a receptor (5HT1aR) activation. This developmental change in activity may be due to changes in the number of serotonergic fibers and/or 5-HT1a receptor density. Using the NIH Basic Local Alignment Search Tool (BLAST) we compared human and bullfrog 5HT1aR and tryptophan hydroxylase 2 (TH2) protein sequences and found a 34 and 65 percent identity match respectively. Quantitative western blot analysis of both proteins indicates developmental shifts in the serotonergic network during metamorphosis. These results were supported by immunohistochemical staining of 5HT1aR and TH2 in caudal raphe containing brainstem sections from pre-metamorphic tadpoles and post-metamorphic frogs. Impairments in the maturation of this serotonergic network may underlie the toxidrome associated with developmental nicotine exposure and further support the increased risk of SIDS following that exposure. This research was supported by the University of Wisconsin- La Crosse (UWL) through support from the UWL College of Science and Health, two UWL Undergraduate Research Creative Grants and a UWL FY23/24 Faculty Research Grant. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Developmental trajectory of intestinal MDR1/ABCB1 mRNA expression in children

Developmental trajectory of intestinal <scp>MDR1/ABCB1</scp> mRNA expression in children

Developmental pattern in the formation of various multienzyme complexes associated with Benson-Calvin cycle in cotton leaves

An electrophoretically homogeneous preparation of a multienzyme complex with a mol wt of 520 ± 20 kD was isolated from 15- to 25-day-old cotton (Gossypium hirsutum L.) leaves uniform in their age and position on the shoot (3rd to 4th leaves from the top when the plants possessed 5–6 true leaves). When cotton leaves were sampled at the stage of budding and flowering, two complexes with mol wts of 520 ± 20 kD and 480 ± 15 kD were isolated. Comparative enzymatic studies of these complexes revealed developmental changes in activities of ribose phosphate isomerase, phosphoribulokinase, and ribulose-bisphosphate carboxylase. The multienzyme complexes were almost identical in activity of ribose phosphate isomerase. Activities of phosphoribulokinase and ribulose-bisphosphate carboxylase for various multienzyme complexes showed variations between 14 and 17% in the presence of ribose-5-phospate + ATP as a substrate, but the differences were smaller (6–7%) in the presence of specific substrates of these enzymes. The formation of multienzyme Benson-Calvin cycle complexes, featuring different properties at various stages of plant development, is presumably related to the increased demand in assimilates for epigenetic processes during formation of generative organs.

Developmental changes in the activities of enzymes of free multienzyme complexes involved in the Benson-Calvin cycle

The electrophoretically homogenous preparations of free multienzyme complexes involved in the Benson-Calvin cycle with mol wt of 520 ± 20 and 240 ± 10 kD were isolated from 15–25-day-old cotton (Gossypium hirsutum L.) leaves of the same story (the third and the fourth upper leaves). Enzyme preparations were obtained at three stages of plant development: at the stage of 6–8 true leaves, during flower-bud formation, and during flowering. Comparison studies of developmental changes in activities of ribose phosphate isomerase (RPI), phosphoribulokinase (PRK), and Rubisco were carried out. RPI and PRK activities of multienzyme complexes differed insignificantly (by 2.3% on the average). Significant changes were observed in Rubisco activity (by 30% on the average). The optimum enzymatic activities of these complexes as well as the highest photosynthetic rate were revealed at the stage of reproductive organ formation. This correlation indicates the major role of multienzyme complexes involved in the Benson-Calvin cycle in the developmental control of photosynthesis and epigenesis.

Developmental changes in the neural mechanisms of eyeblink conditioning.

Eyeblink conditioning has been used as a model system for examining the ontogeny of associative learning and its neural basis in rodents. Associative eyeblink conditioning emerges between postnatal days (P) 17 and 24 in rats. Neurophysiological studies in infant rats during eyeblink conditioning revealed developmental changes in the activity of cerebellar neurons that correspond to the ontogenetic emergence of eyeblink conditioning. The developmental changes in cerebellar neuronal activity suggest that the ontogeny of eyeblink conditioning is related to changes in learning mechanisms rather than motor performance mechanisms. Additional neurophysiological and neuroanatomical studies demonstrated that the developmental changes in neuronal activity in the cerebellum are due to developmental changes in interactions between the cerebellum and its inputs, the inferior olive and pontine nuclei. Developmental changes in cerebellar inputs and regulation of its inputs affect the induction of learning-related plasticity, thereby affecting the rate and magnitude of conditioning.

An enzyme histochemical and biochemical study of the activity of three oxidative enzymes in the developing rat parotid gland

Information on ductal differentiation in the developing rat parotid gland is sparse. One of the main functions of the striated and excretory ducts in this gland is the selective exchange of electrolytes from the primary fluid secreted by the acini. These ducts are rich in a number of enzymes involved in this task, suggesting that they might be useful as markers of ductal differentiation. The objective of this investigation was to delineate the developmental changes in activity of three of these, cytochrome C oxidase (CCO), succinate dehydrogenase (SDH), nicotinamide adenine phosphate dinucleotide (reduced form)-dehydrogenase (NADPH-DH). Histochemical localization of all three enzymes in fresh frozen sections was complemented by biochemical assays of CCO and SDH and cytochemical localization of CCO. Biochemically, CCO- and SDH-specific activity in gland homogenates increased progressively after birth, reaching adult levels at 21-28 days. Histochemically, deposits of reaction products of all three enzymes increased more in the striated and excretory ducts, especially in their basal cytoplasm, than in other glandular structures between 19 days in utero and 28 days after birth. During the same age span, the mitochondria in the striated and excretory ducts increased markedly in both number and size, migrated to a mostly basal location, and increased from many to virtually all showing strong cytochemical CCO reactions. These histochemical and cytochemical patterns of changes in enzyme activity at the cellular level accounted for the overall increases in CCO and SDH seen in the biochemical assays. Only the SDH histochemical reaction was consistently weak in the acini and intercalated ducts, and thus provided the most contrast with the progressively stronger reactions in the larger ducts. We conclude that of the three enzymes evaluated in these experiments, SDH is the best marker of the functional differentiation of the striated and excretory ducts in the developing rat parotid gland.

An enzyme histochemical and biochemical study of the activity of three oxidative enzymes in the developing rat parotid gland

Information on ductal differentiation in the developing rat parotid gland is sparse. One of the main functions of the striated and excretory ducts in this gland is the selective exchange of electrolytes from the primary fluid secreted by the acini. These ducts are rich in a number of enzymes involved in this task, suggesting that they might be useful as markers of ductal differentiation. The objective of this investigation was to delineate the developmental changes in activity of three of these, cytochrome C oxidase (CCO), succinate dehydrogenase (SDH), nicotinamide adenine phosphate dinucleotide (reduced form)-dehydrogenase (NADPH-DH). Histochemical localization of all three enzymes in fresh frozen sections was complemented by biochemical assays of CCO and SDH and cytochemical localization of CCO. Biochemically, CCO- and SDH-specific activity in gland homogenates increased progressively after birth, reaching adult levels at 21-28 days. Histochemically, deposits of reaction products of all three enzymes increased more in the striated and excretory ducts, especially in their basal cytoplasm, than in other glandular structures between 19 days in utero and 28 days after birth. During the same age span, the mitochondria in the striated and excretory ducts increased markedly in both number and size, migrated to a mostly basal location, and increased from many to virtually all showing strong cytochemical CCO reactions. These histochemical and cytochemical patterns of changes in enzyme activity at the cellular level accounted for the overall increases in CCO and SDH seen in the biochemical assays. Only the SDH histochemical reaction was consistently weak in the acini and intercalated ducts, and thus provided the most contrast with the progressively stronger reactions in the larger ducts. We conclude that of the three enzymes evaluated in these experiments, SDH is the best marker of the functional differentiation of the striated and excretory ducts in the developing rat parotid gland.

Developmental changes of vitamin K epoxidase and reductase activities involved in the vitamin K cycle in human liver.

We examined the developmental changes in activities of vitamin K epoxidase, and vitamin K-2,3-epoxide reductase and vitamin K reductase in the human autopsied liver. The activity of epoxidase, which converts vitamin K hydroquinone to its epoxide, showed a high value in the early prenatal period of 10-30 gestational weeks but decreased rather rapidly in contrast with the reductase activities. After birth, a significant decrease of the epoxidase activity was observed but no such change was seen during the postnatal period. On the other hand, the activities of vitamin K-2,3-epoxide reductase and vitamin K reductase, which convert vitamin K-2,3-epoxide to its hydroquinone, showed a significantly low value in the early prenatal period. The highest activity of vitamin K epoxidase in the early prenatal period may be essential to the production of vitamin K dependent ligands for growth factors expressed in the embryo.

Purification and characterization of nitrate reductase from nodule cytosol of soybean plants

Nodulated soybean (Glycine max [L.] Merr.) plants were grown in a nitrogen‐free liquid culture medium prepared with distilled water. The cytosol fraction from root nodules showed a significant level of NADH‐dependent nitrate reductase activity, even when the root did not show activity. This nitrate reductase was purified by column chromatography and native polyacrylamide gel electrophoresis (PAGE). The purified protein showed a main band at 100 kDa on sodium dodecyl sulfate (SDS)‐PAGE. The Km value for nitrate was 0.16 mM, and the highest activity was obtained at around pH 7.5. These characteristics are very similar to the inducible type of nitrate reductase, previously purified from soybean leaves. The developmental change in activity of this enzyme corresponded to that in nitrogenase activity.

Development of pH regulatory transport in glomerular mesangial cells.

Developmental changes in activity or expression of transporters may account for alterations in cell behavior as the nonpolarized cell matures. We sought to ascertain whether there is a maturational change in each of the major acid-base transporters in the developing mesangial cell (MC), the Na/H exchanger, Na-dependent Cl/HCO3 exchanger, and the Cl/HCO3 exchanger. Intracellular pH (pHi) was determined by the use of the fluorescent pH-sensitive dye, 2',7'-bis(2- carboxyethyl)-5(6)-carboxyfluorescein (BCECF). We assessed transporter activity by studying recovery from an acid load (NH4/NH3) in CO2/HCO3. In adult MCs, Na/H exchanger was responsible for 35.2 +/- 4.3% of steady-state pHi, whereas the Na-dependent Cl/HCO3 exchanger contributed 58.7 +/- 6.1 (n = 14). In term MCs (tMCs), from days 1-3 after birth, the Na/H exchanger contributes 62.9 +/- 7.8% (n = 11, P < 0.001 vs. adult), whereas the Na-dependent Cl/HCO3 exchanger contributes 34.0 +/- 5.7% (n = 12, P < 0.001 vs. adult), to the rate of recovery from an acid load in these cells. However, in tMCs (days 4-6), the Na/H contributes 47.2 +/- 5.9% (n = 8, P < 0.05 vs. adult), whereas the Na-dependent Cl/HCO3 exchanger contributes 48.7 +/- 7.3% (n = 13, P < 0.05 vs. adult), to the rate of recovery. tMCs (days 6-12) yielded transporter activity that was not statistically different than adult MCs (37.8 +/- 4.9 and 54.3 +/- 10.2% for Na/H and Na-dependent Cl/HCO3, respectively). The magnitude of the stimulated response to angiotensin II by Na/H and Na-dependent Cl/HCO3 exchanger in adult and tMCs is unchanged throughout development. The Na/H exchanger appears to play a greater role in pHi homeostasis earlier on in development, and this may reflect developmental needs of the maturing cell.

Developmental changes in activity of leucyl-β-naphthylamidase of Malpighian tubules in the silkworm, Bombyx mori

Developmental changes in activity of leucyl-β-naphthylamidase of Malpighian tubules in the silkworm, Bombyx mori

Developmental regulation and partial characterization of growth factors in the bovine mammary gland

Bovine mammary gland secretions from several developmental stages were shown to stimulate [3H]thymidine incorporation into AKR-2B mouse embryo fibroblast cells. In virgin heifers, mammary secretions at 1% concentration stimulated thymidine incorporation into AKR-2B cells more than threefold compared with 10% (v/v) fetal calf serum. The growth-promoting activity peaked at an early stage of the last trimester (7-8 months) of gestation and declined after this until the colostrum forming stage. At this point, the activity was one- to twofold that induced by 10% (v/v) fetal calf serum. At parturition the activity dropped abruptly to virtually undetectable values in milk. The developmental change in activity could be mimicked by hormonal priming of the mammary gland. The partial characterization of the growth promoting activities in secretions at the seventh month of gestation revealed at least two major growth-promoting activities: bovine mammary derived growth factor 1 (bMDGF-1), an epidermal growth factor-like growth factor with a molecular weight of 30,000, which is trypsin sensitive and heat stable, and bMDGF-2, which eluted under gel filtration conditions at a molecular weight of 50,000 and 150,000. bMDGF-1 is predominant in pregnant, precolostric, and colostric secretions, and is not detected in milk. bMDGF-2 is the major growth factor in milk. These results show developmental regulation and modulation of growth-promoting factors during the different stages of mammary gland development and suggest that growth factors are involved in regulating growth during gestation.

Differential Ontogenic Regulation of Basolateral and Canalicular Bile Acid Transport Proteins in Rat Liver

The hepatic transport systems mediating bile acid uptake and excretion undergo independent, stage-specific expression during development in the rat. In this study, the mechanisms underlying ontogenic regulation of both the Na(+)-dependent basolateral bile acid transporter and canalicular bile acid transporter/ecto-ATPase were examined. Steady state mRNA levels for the basolateral transporter were less than 20% of adult values prior to birth, increased to 35% on the first postnatal day, and reached adult levels by 1 week of age. This was paralleled by transcription rates, which were low prior to birth, reached 47% by day 1, and were maximal by 1 week of age. Steady state mRNA levels for ecto-ATPase were 12% of adult values prior to birth and showed a 2-fold increase by the first day of life. Thereafter, there was a gradual increase in mRNA for this transporter, with adult levels being reached at 4 weeks of age. Transcription rates paralleled this increment, although adult levels were reached earlier. Surprisingly, for both transporters, the full complement of protein was present well before adult levels of mRNA were reached. The basolateral protein was expressed at 82% of adult levels on the first day of life but was of lower apparent molecular mass (39 kDa), a difference that persisted until 4 weeks of age. N-Glycanase digestion suggested that this difference could be fully accounted for by N-linked glycosylation. The ecto-ATPase protein was present at 33% of adult levels prior to birth, 77% by 1 day, and 84% of adult levels by 1 week of age. Unlike the basolateral transporter, the apparent molecular weight of this protein did not change during development. In summary, the ontogeny of bile acid transporters on the plasma membrane of the hepatocyte is complex and appears to be regulated at transcriptional, translational, and post-translational levels.

Characterization of 11 beta-hydroxysteroid dehydrogenase activity in fetal and adult ovine tissues.

11 Beta-hydroxysteroid dehydrogenase (11 beta-HSD) converts 11-hydroxycorticosteroids to 11-oxocorticosteroids, thereby influencing the availability of bioactive cortisol or corticosterone in target tissues. The activity of this enzyme was investigated in sheep by: (1) measuring relative 11 beta-HSD activities in kidney, liver and placenta, and in various areas of the brain (hypothalamus, hippocampus, and brainstem); (2) characterizing the optimum pH of activities in the tested tissues; (3) investigating the possible effect of gonadal steroids on 11 beta-HSD activity in adult hypothalamus and kidney; and (4) investigating possible developmental changes in activities in the tested tissues. The optimum pH in liver and placenta was pH 9-10, whereas the optimum pH in kidney was pH 7-8. In tissues from adult ewes, 11 beta-HSD activity was highest in liver (84.6 +/- 3.8%) and kidney (49.8 +/- 11.6%), lower but measurable in pituitary (38.8 +/- 3.7%), and near the limit of detection in hypothalamus and hippocampus (2.7 +/- 0.9% and 3.2 +/- 0.8% respectively). Liver, kidney and pituitary from late-gestation fetal sheep contained activities which were similar to those in the adult (76.9 +/- 4.5%, 66.0 +/- 6.7% and 26.3 +/- 3.0% respectively). Activity in the pituitary was not related to fetal gestational age. Placenta also contained measureable 11 beta-HSD activity (21.4 +/- 4.7%). However, no activity was detected in hypothalamus (-1.7 +/- 0.2%), hippocampus (-0.2 +/- 0.6%) or brainstem (-1.0 +/- 0.6%) in late-gestation fetal or neonatal sheep. Enzyme activities in kidney and hypothalamus did not change significantly when the circulating concentrations of ovarian steroids were altered over a 1-3-week period. It is concluded that the ovine kidney, liver and placenta, but not hypothalamus or cerebral cortex, contain 11 beta-HSD activity. In addition, there is no change in 11 beta-HSD activity between late-gestation fetal life and adult life, and the relative activities are not altered by the ovarian steroid milieu.

Developmental change in activity of red cell porphobilinogen deaminase and its electrophoretic variant in the Japanese population.

The activity of porphobilinogen deaminase (PBGD), an enzyme whose partial deficiency is associated with acute intermittent porphyria (AIP), changes during development. Little is known about the postnatal change of PBGD activity and the prevalence of its electrophoretic variant in the Japanese population. The activity of PBGD was measured fluorometrically in 194 infants aged 0-12 months, while isoelectric focusing of PBGD was performed in 400 healthy Japanese adults aged 20-45 years and 30 children with various hematological disorders aged 1-15 years. The PBGD level was 1.9 times higher in the neonates than in the adults, decreased abruptly during the first month of life, and reached the adult level at the age of 9 months. None of the 400 healthy Japanese adults and the 30 children with hematological disorders showed any electrophoretic variant. These results suggest that there is no need to consider any polymorphism in the gene dose study of PBGD and that the biochemical screening of AIP is applicable to since the late infancy.

1125 Developmental changes in activity of cultured cortical neural networks

1125 Developmental changes in activity of cultured cortical neural networks

Developmental changes in the activity of membrane‐bound γ‐glutamyl transpeptidase and in the sialylation of synaptosomal membranes from the chick embryonic brain

gamma-Glutamyl transpeptidase (GGT) is a membrane-bound sialoglycoprotein. The developmental changes in GGT activity and in sialic acid content were determined in a crude synaptosomal membrane fraction from the cerebral hemispheres of the chick embryo between days 11 and 19 of incubation. The GGT activity increased almost eightfold during the examined developmental period, while sialic acid content rose significantly only between days 11 and 15. Cortical administered on day 13 significantly increased GGT activity. On the other hand, the content of membrane bound sialic acid was not substantially affected. The value of the GGT apparent Michaelis constant (Kmapp) for gamma-glutamyl-p-nitroanilide in the presence of 20 mmol.l-1 glycylglycine was 1.5 mmol.l-1 and cortisol did not influence it. However, Vmax was increased by this hormone. The affinity of GGT to concanavalin A (ConA) did not change during development. Neither the administration of cortisol nor neuroaminidase treatment had any effect on the interaction of GGT with ConA. Desialylation of crude synaptosomal fraction did not change GGT activity. The results presented here suggest no developmental nor functional relationship between the activity of GGT and the level of sialylation in synaptosomal membranes from the cerebral hemispheres of the chick embryo.

Activity changes of guanylate cyclase and cyclic GMP phosphodiesterase related to the accumulation of cyclic GMP in developing ovaries of the silkworm, Bombyx mori

1. 1. Guanylate cyclase in ovaries of the silkworm, Bombyx mori, was not unusual in kinetic properties and mainly localized in the particulate fraction. Two cyclic GMP phosphodiesterases, low- K m (2.9 μM) and high- K m (125.5 μM) enzyme, were found in the soluble fraction of ovaries. 2. 2. All the enzymes showed the similar developmental changes in activity exhibiting a peak value in young ovaries. 3. 3. The cyclic GMP concentrations calculated from these enzyme activities increased according to ovarian development, which resembled the developmental changes in measured values except for the first two days. 4. 4. The calculated concentrations of cyclic GMP were high in ovaries with the removal of suboesophageal ganglion during the last period of development.

Developmental change in activity of N-acetyl-.BETA.-glucosaminidase and a comparison of its multiple enzyme activities in the masseter muscle of normal and dystrophic mice.

Developmental change in activity of N-acetyl-.BETA.-glucosaminidase and a comparison of its multiple enzyme activities in the masseter muscle of normal and dystrophic mice.

Variation and Developmental Change in Activity of Gregarious Caterpillars, Hemileuca Lucina (Saturniidae)

Variation and Developmental Change in Activity of Gregarious Caterpillars, Hemileuca Lucina (Saturniidae)