Epidermal growth factor, transforming growth factor-α, and epidermal growth factor receptor expression and localization in the canine endometrium during the estrous cycle and in bitches with pyometra

Gene expression and immunohistochemical localization of epidermal growth factor (EGF), transforming growth factor-α (TGF-α), and epidermal growth factor receptor (EGF-R) were compared between the endometrium of bitches (Canis familiaris) with pyometra accompanied by cystic endometrial hyperplasia (CEH) and that of healthy bitches at similar stages of the estrous cycle. In normal bitches, endometrial TGF-α mRNA levels were highest at proestrus and gradually decreased as the cycle progressed to anestrus. Epidermal growth factor receptor mRNA levels were not significantly affected by the stage of the estrous cycle. Epidermal growth factor mRNA levels were higher at Day 35 of diestrus than at other stages of the estrous cycle (P < 0.05). In bitches with pyometra, endometrial TGF-α and EGF-R mRNA levels did not differ significantly from those at diestrus in normal bitches, but EGF mRNA levels were lower than those at Day 35 of diestrus in normal bitches (P < 0.05). In normal bitches, positive immunohistochemical staining for TGF-α, EGF, and EGF-R was mainly present in the glandular and luminal epithelial cells of the endometrium. In contrast, in bitches with pyometra, immunoreactivity for EGF was clearly present in endometrial stromal cells. Inflammatory cells that had infiltrated the endometrial stroma stained strongly for TGF-α and EGF-R. Luminal and glandular epithelial cells also stained positive for EGF-R. In conclusion, expression of TGF-α by inflammatory cells and a low level of expression and differential localization of EGF may be involved in aberrant growth of endometrial glands and development of CEH.     

Cyclooxygenases and prostaglandin E2 receptors in growth plate chondrocytes in vitro and in situ – prostaglandin E2 dependent proliferation of growth plate chondrocytes

Prostaglandin E₂ (PGE₂) plays an important role in bone development and metabolism. To interfere therapeutically in the PGE₂ pathway, however, knowledge about the involved enzymes (cyclooxygenases) and receptors (PGE₂ receptors) is essential. We therefore examined the production of PGE₂ in cultured growth plate chondrocytes in vitro and the effects of exogenously added PGE₂ on cell proliferation. Furthermore, we analysed the expression and spatial distribution of cyclooxygenase (COX)-1 and COX-2 and PGE₂ receptor types EP1, EP2, EP3 and EP4 in the growth plate in situ and in vitro. PGE₂ synthesis was determined by mass spectrometry, cell proliferation by DNA [³H]-thymidine incorporation, mRNA expression of cyclooxygenases and EP receptors by RT-PCR on cultured cells and in homogenized growth plates. To determine cellular expression, frozen sections of rat tibial growth plate and primary chondrocyte cultures were stained using immunohistochemistry with polyclonal antibodies directed towards COX-1, COX-2, EP1, EP2, EP3, and EP4. Cultured growth plate chondrocytes transiently secreted PGE₂ into the culture medium. Although both enzymes were expressed in chondrocytes in vitro and in vivo, it appears that mainly COX-2 contributed to PGE₂-dependent proliferation. Exogenously added PGE₂ stimulated DNA synthesis in a dose-dependent fashion and gave a bell-shaped curve with a maximum at 10^-8 M. The EP1/EP3 specific agonist sulprostone and the EP1-selective agonist ONO-D1-004 increased DNA synthesis. The effect of PGE₂ was suppressed by ONO-8711. The expression of EP1, EP2, EP3, and EP4 receptors in situ and in vitro was observed; EP2 was homogenously expressed in all zones of the growth plate in situ, whereas EP1 expression was inhomogenous, with spared cells in the reserve zone. In cultured cells these four receptors were expressed in a subset of cells only. The most intense staining for the EP1 receptor was found in polygonal cells surrounded by matrix. Expression of receptor protein for EP3 and EP4 was observed also in rat growth plates. In cultured chrondrocytes, however, only weak expression of EP3 and EP4 receptor was detected. We suggest that in growth plate chondrocytes, COX-2 is responsible for PGE₂ release, which stimulates cell proliferation via the EP1 receptor.     

Immunohistochemical localization of transforming growth factor-α and epidermal growth factor-receptor in the mesonephros and metanephros of the chicken

Summary Transforming growth factor-alpha (TGF-) is a polypeptide related to epidermal growth factor (EGF). Both bind to EGF-receptor (EGF-R) to carry out their function in a variety of tissues and cell lines. Several studies have shown their presence in mammalian kidney, however, nothing has to date been stated concerning their existence in avian kidney. Expression of TGF- and EGF-R is reported here for the first time during the development of the chicken kidney. Using immunohistochemical techniques, we identified a TGF- (but not EGF) in mesonephric distal tubule cells from day 8 to day 20 of embryonic development and in metanephric distal tubule cells from day 14 of embryonic development to the adult. The histochemical characteristics of these cells and their histological localization suggest that they may be the principal cells of the distal tubules. Similarly, EGF-R was found in mesonephric proximal tubule cells from day 7 to day 18 of embryonic development and in metanephric proximal tubule cells from day 13 of embryonic development up to adult stages. The coexistence of both TGF- and EGF-R from the onset of development of mesonephros and metanephros supports their possible role in mechanisms of proliferation and differentiation of the cells of these organs.     

Developmental expression of transforming growth factor-α and epidermal growth factor receptor proteins in the human pancreas and digestive tract

This study was designed to localize transforming growth factor alpha (TGF-) and epidermal growth factor receptor (EGFR) expression in the developing human gastrointestinal tract and pancreas. Immunohistochemical techniques using specific antibodies against human TGF- and EGFR were performed on digestive tissues of fetuses from 9 to 10 to 24 weeks of gestation, children and adults. In fetuses, TGF- and EGFR proteins were expressed in all epithelial tissues studied with a good correlation and from an age as early as 9 to 10 weeks of gestation, except for TGF- in the esophagus. The strongest TGF- immunostaining was noted in the stomach and the proximal colon. Unexpectedly, immunoreactive gut endocrine cells were observed with the two antibodies used. Relatively numerous in fetuses, they decreased in number with age and were rare in adults particularly along the colon. Enteroglucagon-secreting cells were shown to express TGF- while some gastrin, somatostatin and pancreatic glucagon cells were immunostained with EGFR antibodies. The presence of TGF- and of its recetor in digestive tract epithelium and pancreatic tissues early in fetal life suggests a functional role for TGF- during the developmental process of the digestive system. We demonstrate that TGF- is also produced by endocrine cells and might have an additional mode of action other than paracrine, at least during fetal life.     

Transforming growth factor-β receptors: Role in physiology and disease

Transforming growth factor- (TGF-) plays a pivotal role in numerous vital cellular activities, most significantly the regulation of cellular proliferation and differentiation and synthesis of extracellular matrix components. Its ubiquitous presence in different tissues and strict conservation of nucleotide sequence down through the most primitive vertebrate organisms underscore the essential nature of this family of molecules. The effects of TGF- are mediated by a family of dedicated receptors, the TGF- types I, II, and III receptors. It is now known that a wide variety of human pathology can be caused by aberrant expression and function of these receptors or their cognate ligands. The coding sequence of the human type II receptor appears to render it uniquely susceptible to DNA replication errors in the course of normal cell division. There are now substantial data suggesting that TGF- type II receptor should be considered a tumor suppressor gene. High levels of mutation in the TGF- type II receptor gene have been observed in a wide variety of primarily epithelial malignancies, including colon, gastric, and hepatic cancer. It appears likely that mutation of the TGF- type II receptor gene represents a very critical step in the pathway of carcinogenesis.     

Aging,osteoarthritis and transforming growth factor-β signaling in cartilage

Osteoarthritis is a common malady of the musculoskeletal system affecting the articular cartilage. The increased frequency of osteoarthritis with aging indicates the complex etiology of this disease, which includes pathophysiology and joint stability including biomechanics. The balance between anabolic morphogens and growth factors and catabolic cytokines is at the crux of the problem of osteoarthritis. One such signal is transforming growth factor-β (TGF-β). The impaired TGF-β signaling has been identified as a culprit in old mice in a recent article in this journal. This commentary places this discovery in the context of anabolic and catabolic signals and articular cartilage homeostasis in the joint.     

Fungal mutualists enhance growth and phytochemical content in Echinacea purpurea

An emerging paradigm in sustainable biotechnique is the use of mutualists to enhance plant growth and secondary metabolism. Our objective was to determine impact of two groups of fungal mutualists on growth and phytochemistry of Echinacea purpurea. Growth, development, and phytochemical concentration were measured in greenhouse-grown 12-week-old plants colonized by arbuscular mycorrhizal fungi (AMF) (Rhizophagus intraradices and Gigaspora margarita) or the endophytic entomopathogen, Beauveria bassiana. In one experiment, all measured growth parameters were increased in mycorrhizal plants. Biomass of AMF-colonized plants was over 13-fold greater than non-mycorrhizal controls receiving the same levels of phosphorous, and over 4-fold greater than non-mycorrhizal controls given additional phosphorous. Endophytic colonization by B. bassiana had minor effects on growth. Colonization by AMF and B. bassiana alone or in combination altered concentrations of phytochemicals (pigments, polyphenolics, alkylamides, and terpenes). Mycorrhizal plants produced up to 4.6-fold higher concentration of polyphenolics. Specific alkylamides increased 1.7 fold in plants colonized only with B. bassiana and up to a 2.4-fold increase in plants colonized by both mutualists. Changes in other phytochemical classes were related to differences in plant size induced by AMF. Phytochemical content (concentration × biomass) was increased up to 30-fold in mycorrhizal plants. Phytochemical relationships to plant biomass were confirmed in a second experiment in which non-mycorrhizal plants were fertilized to produce biomass equivalent to that of mycorrhizal plants. Based on this study, mycorrhizal colonization of E. purpurea enhances phytochemical content; this has major implications for the natural product industries and growers of E. purpurea.     

Population growth and economic development in Chiapas, 1524–1975

In a recent work on the Tzotzil (Maya) of Chiapas, Mexico, George Collier has suggested that indigenous groups frequently employ agricultural practices which are in obvious disequilibrium with their environment. As a result, he claims, such groups bring about the permanent destruction of their lands and forests. In this article, historical and demographic evidence is presented to demonstrate that the development of commencal agriculture outside of native communities, not overpopulation or technological conservatism within them, lies at the heart of such destruction. Finally, it is argued that anthropologists must consider the evolution of social classes in rural areas if they are to understand the difficulties which economic development entails.     

NanoAOX—a novel nanoparticle and antioxidant mixture enhances the growth of plants in vitro and in vivo

In Vitro Cellular & Developmental Biology - Plant - The global food crisis is an issue affecting 1 billion people worldwide—it is critical that a solution be developed to provide the...     

Intrauterine growth retardation and consequences for endocrine and cardiovascular diseases in adult life: does insulin-like growth factor-I play a role?

Low birth weight has been associated with an increased incidence of ischaemic heart disease (IHD) and type 2 diabetes. Endocrine regulation of fetal growth by growth hormone (GH) and insulin-like growth factor (IGF)-I is complex. Placental GH is detectable in maternal serum from the 8th to the 12th gestational week, and rises gradually during pregnancy where it replaces pituitary GH in the maternal circulation. The rise in placental GH may explain the pregnancy-induced rise in maternal serum IGF-I levels. In the fetal compartment, IGF-I levels increase significantly in normally growing fetuses from 18 to 40 weeks of gestation, but IGF-I levels are four to five times lower than those in the maternal circulation. Thus IGF-I levels in fetal as well as in maternal circulation are thought to regulate fetal growth. Circulating levels of IGF-I are thought to be genetically controlled and several IGF-I gene polymorphisms have been described. IGF-I gene polymorphisms are associated with birth weight in some studies but not in all. Likewise, IGF-I gene polymorphisms are associated with serum IGF-I in healthy adults in some studies, although some controversy exists. Serum IGF-I decreases with increasing age in healthy adults, and this decline could hypothetically be responsible for the increased risk of IHD with ageing. A recent nested case-control study found that adults without IHD, but with low circulating IGF-I levels and high IGF binding protein-3 levels, had a significantly increased risk of developing IHD during a 15-year follow-up period. In summary, the GH/IGF-I axis is involved in the regulation of fetal growth. Furthermore, it has been suggested that low IGF-I may increase the risk of IHD in otherwise healthy subjects. Hypothetically, intrauterine programming of the GH/IGF axis may influence postnatal growth, insulin resistance and consequently the risk of cardiovascular disease. Thus IGF-I may serve as a link between fetal growth and adult-onset disease.     

Expression of transforming growth factor-α mRNA and peptide in rodent kidneys

The expression and function of transforming growth factor alpha (TGF-α) in the kidney are not fully characterised. There exists controversy concerning the detection of renal TGF-α mRNA and the localisation of its immunoreactivity. In attempts to clarify the detection and localisation issue, the present study aimed to detect TGF-α mRNA in neonate and adult rat kidneys, to examine the specificity of two commonly used anti-TGF-α antibodies and finally to localise renal TGF-α immunoreactivity using a specific antibody. TGF-α mRNA of around 4.8 kb was readily detected with a sensitive non-radioactive northern analysis, with a similar abundance in neonatal and adult rat kidneys. Renal TGF-α peptide of the 6-kDa mature form was identified by western blotting. By using various controls, including specimens from TGF-α knock out mice in comparison with wild-type mice, the present study has confirmed the specificity of a polyclonal anti-human recombinant TGF-α antibody. With this antibody, TGF-α immunoreactivity was localised to the proximal tubules in renal cortex. In addition, the present study has also demonstrated a non-specificity in localising TGF-α in rodent kidneys by the most commonly used monoclonal anti-human TGF-α C-terminal peptide antibody, which stained collecting ducts in renal cortex and medulla. Accepted: 8 April 1999     

Cell wall functions in growth and development —a physical and chemical point of view

The plant cell changes its cell wall architecture during growth and development through synthesis and degradation of wall polysaccharides. Changes of chemical components in the cell wall include not only the synthesis and degradation but also the shift of molecular-weight distribution of certain species of the component polysaccharides. The changes in chemical structure, in turn lead to alteration of physical properties of the cell wall. Changes of physical parameters of cell walls obtained by a physical method accord with the biochemical degradation of polysaccharides. The changes in chemical structures of the cell wall are regulated by plant hormones, stress signals and gene expression. The physical and chemical studies of the cell wall have disclosed that degradation and/or depolymerization of wall polysaccahrides causes decrease in viscosity of the cell wall, leading further extension of the cell wall even under the unchanged osmotic relation. Furthermore, cell walls of outer and inner tissues play different regulatory roles in tissue growth and stem strength was governed by the number of cellulose molecules in the cell wall. Recipient of the Botanical Society Award for Young Scientists, 1990.     

Fetal concentrations of the growth factors TGF-α and TGF-β1 in relation to normal and restricted fetal growth at term

Transforming growth factor-α (TGF-α) and TGF-β1 are major anti-inflammatory cytokines and substantially contribute to normal pregnancy outcome. TGF-α stimulates placental mitosis, whereas TGF-β1 is a critical regulator of trophoblast invasion and fetal growth. We aimed to study cord blood TGF-α and TGF-β1 concentrations in intrauterine-growth-restricted (IUGR, usually associated with abnormal trophoblast invasion, uteroplacental vascular insufficiency and enhanced inflammation) and appropriate-for-gestational-age-(AGA) pregnancies, and investigate possible correlations of the above concentrations with several demographic parameters of infants at birth. Plasma TGF-α and TGF-β1 concentrations were determined by ELISA in 154 mixed arterio-venous cord blood samples from IUGR (n=50) and AGA (n=104) singleton full-term infants. After controlling for possible confounding factors (gender, birth-weight, gestational age, maternal age and parity), cord blood TGF-α and TGF-β1 concentrations were significantly higher in IUGR than AGA group (b=0.402, SE=0.179, p=0.027 and b=0.152, SE=0.061, p=0.014, respectively). Delivery mode had an effect on cord blood TGF-α and TGF-β1 concentrations, both being elevated in cases of vaginal delivery (b=-0.282, SE=0.117, p=0.018 and b=-0.123, SE=0.059, p=0.038, respectively). In conclusion, higher cord blood TGF-α and TGF-β1 concentrations may represent a compensatory response to the inflammatory process characterizing the IUGR state. Additionally, higher cord blood TGF-β1 concentrations in IUGRs could be attributed to increased shear stress, resulting from abnormal blood flow in IUGR fetal blood vessels. Finally, vaginal delivery-associated cytokine release may account for elevated TGF-α and TGF-β1 concentrations.     

Bacillus thuringiensis growth,sporulation and δ-endotoxin production in oxygen limited and non-limited cultures

The production of crystals and spores ofBacillus thuringiensis var.israelensis was studied under different aeration conditions. The results with 4 l batch cultures showed that for O₂ non-limited, cultures cell yield, toxin production and spore count were constant for all oxygen transfer rates (OTR). Under O₂ limitation, °-endotoxin concentrations and spore counts were lower than those obtained in non-limited cultures. In addition, -endotoxin yields diminished under O₂ limitation, suggesting that the toxin synthesis mechanism could have been affected.     

Size mediated climate–growth relationships in Pinus halepensis and Pinus pinea

Functional processes in trees undergo changes as the tree size increases, which may affect the response of trees to environmental factors. We tested tree-ring response to climate in four groups of trees, including large and small Pinus halepensis and Pinus pinea trees using cluster, principal component (PC) and dendroclimatological analysis. The trees were of the same age and growing on a plantation in the semiarid coastal area of southern Spain. Cluster and PC analyses showed a clear separation into four groups of trees. Autocorrelation and mean sensitivity showed significant differences between the two size classes. PCA recognised four representative principal components where PC1 represented the tree-ring—climate variability common to both species and sizes, whereas PC2, PC3 and PC4 represented a species-specific and size-dependent response of trees to climate. The differences between the two size classes were greater than those between the two species. The results suggest that future tree-ring studies should include trees stratified by size. Only this would make it possible to produce unbiased predictions on the consequences of climate change and to devise suitable mitigation strategies for preserving Mediterranean forest ecosystems.     

Dietary fiber enhances TGF-β signaling and growth inhibition in the gut

Dietary fiber intake links to decreased risk of colorectal cancers. The underlying mechanisms remain unclear. Recently, we found that butyrate, a short-chain fatty acid produced in gut by bacterial fermentation of dietary fiber, enhances TGF-β signaling in rat intestinal epithelial cells (RIE-1). Furthermore, TGF-β represses inhibitors of differentiation (Ids), leading to apoptosis. We hypothesized that dietary fiber enhances TGF-β's growth inhibitory effects on gut epithelium via inhibition of Id2. In this study, Balb/c and DBA/2N mice were fed with a regular rodent chow or supplemented with a dietary fiber (20% pectin) and Smad3 level in gut epithelium was measured. In vitro, RIE-1 cells were treated with butyrate and TGF-β(1), and cell functions were evaluated. Furthermore, the role of Ids in butyrate- and TGF-β-induced growth inhibition was investigated. We found that pectin feeding increased Smad3 protein levels in the jejunum (1.47 ± 0.26-fold, P = 0.045, in Balb/c mice; 1.49 ± 0.19-fold, P = 0.016, in DBA/2N mice), and phospho-Smad3 levels (1.92 ± 0.27-fold, P = 0.009, in Balb/c mice; 1.83 ± 0.28-fold, P = 0.022, in DBA/2N mice). Butyrate or TGF-β alone inhibited cell growth and induced cell cycle arrest. The combined treatment of butyrate and TGF-β synergistically induced cell cycle arrest and apoptosis in RIE-1 cells and repressed Id2 and Id3 levels. Furthermore, knockdown of Id2 gene expression by use of small interfering RNA caused cell cycle arrest and apoptosis. We conclude that dietary fiber pectin enhanced Smad3 expression and activation in the gut. Butyrate and TGF-β induced cell cycle arrest and apoptosis, which may be mediated by repression of Id2. Our results implicate a novel mechanism of dietary fiber in reducing the risk of colorectal cancer development.     

Pancreatic beta-cell growth and survival--a role in obesity-linked type 2 diabetes?

Obesity-linked type 2 diabetes is a disease of insulin resistance combined with pancreatic beta-cell dysfunction. Although a role for beta-cell mass in the pathogenesis of obesity-linked type 2 diabetes has recently gained prominence, the idea is still being developed. It is proposed that in early obesity an increase in beta-cell mass and function might compensate for peripheral insulin resistance. However, as time and/or the severity of the obesity continue, there is decay in such adaptation and the beta-cell mass becomes inadequate. This, together with beta-cell dysfunction, leads to the onset of type 2 diabetes. It is becoming evident that elements in insulin and insulin growth factor (IGF)-1 signal-transduction pathways are key to regulating beta-cell growth. Current evidence indicates that interference of insulin signaling in obesity contributes to peripheral insulin resistance. This article examines whether a similar interference of IGF-1 signaling in the beta-cell could hinder upregulation of beta-cell mass and/or function, resulting in a failure to compensate for insulin resistance.     

Salinity induced changes in α-amylase and protease activities and associated metabolism in cotton varieties during germination and early seedling growth stages

The increase in salinity of the medium resulted in the decrease α-amylase and protease activities in all cotton varieties tested, however it was more pronounced in NIAB-86. Decrease in concentration of reducing and non-reducing sugars, slower mobilization of reserve protein and reduced amino acidslevels were observed with increase in salinity levels. However, varieties K-115 showed better performance than others. The variety K-115 also had a capacity to mobilization and had higher levels of sugars, total free amino acids and reserve protein during germination and early seedling growth stages. However, varieties K-115 showed better performance than others. Variety K-115 showed highest germination followed by NIAB-Karishma and NIAB-86. The variety K-115 also had a capacity to mobilization and had higher levels of total free amino acids and less reserve protein during germination and early seedling growth stages.