Glycoproteomic analysis of two mouse mammary cell lines during transforming growth factor (TGF)-β induced epithelial to mesenchymal transition

Background  

TGF-β acts as an antiproliferative factor in normal epithelial cells and at early stages of oncogenesis. However, later in tumor development TGF-β can become tumor promoting through mechanisms including the induction of epithelial-to-mesenchymal transition (EMT), a process that is thought to contribute to tumor progression, invasion and metastasis. To identify EMT-related breast cancer therapeutic targets and biomarkers, we have used two proteomic approaches to find proteins that change in abundance upon the induction of EMT by TGF-β in two mouse mammary epithelial cell lines, NMuMG and BRI-JM01.     

Involvement of fumarase C and NADH oxidase in metabolic adaptation of Pseudomonas fluorescens cells evoked by aluminum and gallium toxicity

Iron (Fe) is a critical element in all aerobic organisms as it participates in a variety of metabolic networks. In this study, aluminum (Al) and gallium (Ga), two Fe mimetics, severely impeded the ability of the soil microbe Pseudomonas fluorescens to perform oxidative phosphorylation. This was achieved by disrupting the activity and expression of complexes I, II, and IV. These toxic metals also inactivated aconitase (ACN) and fumarase A (FUM A), two tricarboxylic acid cycle enzymes dependent on Fe for their catalytic activity, while FUM C, an Fe-independent enzyme, displayed an increase in activity and expression under these stressed situations. Furthermore, in the Al- and Ga-exposed cells, the activity and expression of an H(2)O-forming NADH oxidase were markedly increased. The incubation of the Al- and Ga-challenged cells in an Fe-containing medium led to the recovery of the affected enzymatic activities. Taken together, these data provide novel insights into how environmental pollutants such as Al and Ga interfere with cellular Fe metabolism and also illustrate the ability of Pseudomonas fluorescens to modulate metabolic networks to combat this situation.     

Structure de la glande nasale externe deTiliqua rugosa (Reptilia,Scincidae) et rapports avec sa fonction

Summary The scincid lizardTiliqua rugosa possesses a large external nasal gland which is located intraconchally. Highly ramified tubules, imbedded primarily in the periphery of the gland, unite to form collecting ducts which empty into a short excretory canal. The diameter of the tubules increases progressively from 30. at the distal extremity of the gland to over 200 at the level of the collecting ducts. The intraglandular portion of the excretory canal is often dilated to form an ampulla. The thickness of the epithelium increases from 12 at the level of the tubules to 25–30 in the excretory canal.The excretory canal is lined with an epidermal epithelium close to the point where it enters the vestibule. In all the rest of the gland the tubules are lined with two cell types: large, typical muco-serous cells and striated cells. At the distal end of the tubules the striated cells are narrow and poorly differentiated and alternate more-or-less regularly with the muco-serous cells. The relative proportion of these striated cells increases progressively, as does their size, as one moves proximally down the tubule. In the gland as a whole the striated cells are approximately twice as numerous as the muco-serous cells but, due to their smaller size, they occupy less than one third of the tubular volume.Electron microscopy of the striated cells ofTiliqua rugosa revealed the presence of extensive lateral interdigitations and expansions of the basal cytoplasmic membrane, anatomical specialisations which are normally indicative of active salt transport. These modifications are less marked however than in the external nasal glands of the lizardsLacerta muralis andVaranus griseus, which do not appear to function as salt glands. In addition there are few mitochondria present, although they are of large size. The combination of these ultrastructural features, plus the fact that the striated cells are intermixed with muco-serous cells in the tubules, makes it most unlikely that the external nasal gland ofTiliqua rugosa is capable of elaborating an hyperosmotic fluid. What is more, this has never been conclusively demonstrated in this species in physiological studies.The progressive specialisation of the striated cells from the distal to the proximal section of the tubules poses the problem of the origin and differentiation of this cell type.A review of results obtained from the study ofTiliqua rugosa and other species of lizards shows that the nature of the relationship between structure and function of the external nasal gland is far from clear. The existence of salt glands, capable of excreting hyperosmotic solutions, is invariably linked with the presence in the gland of well-developed striated segments composed almost entirely of cells possessing extensive interdigitations of the lateral membranes. Amongst terrestrial lizards, nasal salt glands are usually found in herbivorous species and they are primarily adapted to the extrarenal excretion of potassium ions. The problem for carnivorous species is more often that of an excess of sodium rather than potassium ions and with the possible exceptionAcanthodactylus species, functional nasal salt glands have not been demonstrated in terrestrial carnivores, despite the presence in some cases of well-developed striated segments in the gland having a similar structure to those found in herbivores. In humid regions, carnivorous lizards probably never require extrarenal excretory mechanism and in arid regions their survival is assured by their capacity to tolerate hypernatraemia when confronted with excessive salt loads. Salt glands capable of eliminating sodium ions to any extent have only been described in two littoral species, an herbivorous iguanid and a carnivorous varanid. Unfortunately the structure of their respective nasal glands has not yet been described and their further study would be desirable.     

Metamorphosis in the Cirripedia Rhizocephala and the homology of the kentrogon and trichogon

The Rhizocephala are considered to be monophyletic due to several synapomorphies in the ontogeny of the cndoparasitic phase. The various types of metamorphosis described in the Rhizocephala are discussed and compared to metamorphosis in the Cirripedia Thoracica and Acrothoracica. In males and females of the suborder Kentrogonida. the cyprid settles and metamorphoses into a new instar, in males the trichogen and in females the infective kentrogon. The kentrogon goes through yet another. incomplete moult associated with the development of the stylet. Within the three kentrogonidan families. the Iernaeodiscid-peltogastrid type of kentrogon differs from the sacculinid type in the mode of attachment to the host. in the complexity of internal anatomy. in the position and penetration of the stylet, and in whether or not the cyprid carapace must be shed prior to penetration of the stylet. In the Akentrogonida metamorphosis never results in a new instar. Where observed (Clistosaccidae and Thompsoniidae). both male and female cyprids settle and penetrate into their substrate (female parasite or new host) with one of the antennules. Using the antennule as a syringe. male cyprids inject spermatogonia while female cyprids injects embryonic cells developing into an endoparasite. By comparison with metamorphosis in the Cirripedia Thoracica and Acrothoracica it is concluded that the presence of a metamorphic moult leading to a post-cyprid instar is plesiomorphic and that the trichogon and kentrogon are homologous with the first metamorphosed juvenile in these outgroups. The abbreviated ontogeny in the Akentrogonida without metamorphic moult and post-cyprid larval instars is considered apomorphic. This contradicts the long-held supposition that the Akentrogonida are the most‘primitive’Rhizocephala and dovetails with new information that this suborder contains many advanced traits. Within the Kentrogonida. the lernacodiseid-peltogastrid type of kentrogon is considered more plesiomorphic than the sacculinid type, which resembles the clistosaccidthompsoniid type in having the antennules involved in the penetration process. The homologization of the kentrogon with a juvenile barnacle indicates that presence of a kentrogon is plesiomorphic within the Rhizocephala and that the Kentrogonida is paraphyletic.     

Atelencephalic microcephaly: craniofacial anatomy and morphologic comparisons with holoprosencephaly and anencephaly

This is the first detailed report of the craniofacial anatomy of atelencephaly. Comparisons were made with a control specimen and others with holoprosencephaly, anencephaly, and anencephaly with holoprosencephalic facial features. In the atelencephalic fetus, severe microcephaly, flattened calvaria, and partial synostosis of the metopic suture were apparent. The cranial fossae were much smaller than usual; lesser wings of the sphenoid were folded into a rounded basal mass. Facial features were pronounced, and orbits were hyperteloric, lowset, and rounded. Ethmoidal cartilages, nasal bones, and maxillary structures were distorted and elongated. The secondary palate was displaced inferiorly and cleft. Because major components of the craniofacial complex were generally present, although misshapen, changes in the atelencephalic skull seem to be deformations rather than malformations. Differences in the cranial morphology of associated disorders--holoprosencephaly and anencephaly--can be construed as aberrations of separate developmental fields. Relationships between atelencephaly and these fields are unclear.     

Concerted transpositions of mobile genetic elements coupled with fitness changes in Drosophila melanogaster

In an inbred low-activity (LA) strain of Drosophila melanogaster with a low level of fitness and a complex of inadaptive characters, in situ hybridization reveals an invariant pattern of distribution of three copia-like elements (mdg-1, mdg-3, and copia). Rare, spontaneous, multiple transpositions of mobile elements in the LA strain were shown to be coupled with a drastic increase of fitness. A changed pattern of various types of mobile elements was also observed on selecting the LA strain for higher fitness. High-fitness strains show transpositions of mobile elements to definite chromosomal sites ("hot spots"). Concerted changes in the location of three different mobile elements were found to be coupled with an increase of fitness. The mdg-1 distribution patterns were also examined in two low-fitness strains independently selected from the high-fitness ones. Fitness decrease was accompanied by mdg-1 excision from the hot spots of their location usually detected in the high-fitness strains. The results suggest the existence of a system of adaptive transpositions of mobile elements that takes part in fitness control.      

Atelencephalic microcephaly in a 21-week human fetus

Atelencephalic microcephaly, a rare and extreme disorder, is known morphologically by only six cases. Derivatives of the telencephalon are absent or dysplastic, while more caudal structures are normal or mildly deformed. A more extensive form, aprosencephaly, involves structures of the diencephalon and may be associated with holoprosencephalic facies. Extracranial anomalies may be present in both atelencephaly and aprosencephaly. We describe the seventh and youngest specimen, a 21-week female with atelencephaly. Maternal and gestational histories were unremarkable; the fetus was obtained by therapeutic abortion following diagnosis of a severe cranial malformation by ultrasound. A small and depressed, but intact, calvarium covered the brain. The forebrain was rounded and showed fused hemispheres, absent gyri, olfactory bulbs, and tracts. Caudal structures were mildly deformed. An oval mass of bone filled much of the middle cranial fossa. By light microscopy, several dysplastic changes were apparent in the forebrain. Ventricles were not present; small round cells resembling those of the germinal matrix were prominent in the forebrain. Pyramidal tracts were absent at all levels. The process responsible for these changes cannot be established with certainty; the changes are, however, in keeping with previous damage, such as that accepted for other encephaloclastic disorders. The insult in atelencephaly presumably occurs after closure of the rostral neuropore; earlier damage, with more widespread consequences, is possible for aprosencephaly. As with other destructive processes, etiology in atelencephaly and aprosencephaly is most likely heterogeneous.     

Evaluating the Metal Tolerance Capacity of Microbial Communities Isolated from Alberta Oil Sands Process Water

Anthropogenic activities have resulted in the intensified use of water resources. For example, open pit bitumen extraction by Canada’s oil sands operations uses an estimated volume of three barrels of water for every barrel of oil produced. The waste tailings–oil sands process water (OSPW)–are stored in holding ponds, and present an environmental concern as they are comprised of residual hydrocarbons and metals. Following the hypothesis that endogenous OSPW microbial communities have an enhanced tolerance to heavy metals, we tested the capacity of planktonic and biofilm populations from OSPW to withstand metal ion challenges, using Cupriavidus metallidurans, a known metal-resistant organism, for comparison. The toxicity of the metals toward biofilm and planktonic bacterial populations was determined by measuring the minimum biofilm inhibitory concentrations (MBICs) and planktonic minimum inhibitory concentrations (MICs) using the MBEC ™ assay. We observed that the OSPW community and C. metallidurans had similar tolerances to 22 different metals. While thiophillic elements (Te, Ag, Cd, Ni) were found to be most toxic, the OSPW consortia demonstrated higher tolerance to metals reported in tailings ponds (Al, Fe, Mo, Pb). Metal toxicity correlated with a number of physicochemical characteristics of the metals. Parameters reflecting metal-ligand affinities showed fewer and weaker correlations for the community compared to C. metallidurans, suggesting that the OSPW consortia may have developed tolerance mechanisms toward metals present in their environment.     

A Novel Strategy Involved Anti-Oxidative Defense: The Conversion of NADH into NADPH by a Metabolic Network

The reduced nicotinamide adenine dinucleotide phosphate (NADPH) is pivotal to the cellular anti-oxidative defence strategies in most organisms. Although its production mediated by different enzyme systems has been relatively well-studied, metabolic networks dedicated to the biogenesis of NADPH have not been fully characterized. In this report, a metabolic pathway that promotes the conversion of reduced nicotinamide adenine dinucleotide (NADH), a pro-oxidant into NADPH has been uncovered in Pseudomonas fluorescens exposed to oxidative stress. Enzymes such as pyruvate carboxylase (PC), malic enzyme (ME), malate dehydrogenase (MDH), malate synthase (MS), and isocitrate lyase (ICL) that are involved in disparate metabolic modules, converged to create a metabolic network aimed at the transformation of NADH into NADPH. The downregulation of phosphoenol carboxykinase (PEPCK) and the upregulation of pyruvate kinase (PK) ensured that this metabolic cycle fixed NADH into NADPH to combat the oxidative stress triggered by the menadione insult. This is the first demonstration of a metabolic network invoked to generate NADPH from NADH, a process that may be very effective in combating oxidative stress as the increase of an anti-oxidant is coupled to the decrease of a pro-oxidant.