Brushed by Cedar, Living by the River: Coast Salish Figures of Power

Brushed by Cedar, Living by the River: Coast Salish Figures of Power. Crisca Bierwert. Tucson: University of Arizona Press, 1999.314 pp.     

Heavy metal and PCB contamination of Bryozoan colonies in the River Meuse (Belgium)

In the Meuse River (Liège area, Belgium), large amounts of three species of Bryozoans, Fredericella sultana (BLUM.), Plumatella emarginata ALL. and Plumatella fungosa (PALL.) occur. They cover 3 to 40% of the bank walls and their biomass ranges from 12 to 293 g m^–2 (dry weight). In the heated waters of a nuclear power plant (Tihange) and of industries lined up along the river, colony development occurs 3 to 4 weeks earlier than at an upstream station. The heavy metal content of living colonies ranges from 4 to 21 mg kg^–1 Cd, 45 to 182 mg kg^–1 Cu, 803 to 2232 mg kg^–1 Zn, 150 to 483 mg kg^–1 Pb and 21 to 138 mg kg^–1 Cr (DW). The mean concentration of PCBs was 925 µg kg^–1 (DW). Heavy metal and PCB concentrations in the sediments were close to those of colonies, suggesting that most of the pollutants found in the Bryozoans is in fact in the sediment trapped by the colonies.     

Specialty oilseed crops provide an abundant source of pollen for pollinators and beneficial insects

The continuing pollinator crisis is due, in part, to the lack of year‐round floral resources. In intensive farming regions, such as the Upper Midwest (UMW) of the USA, natural and pastoral vegetation largely has been replaced by annual crops such as maize (Zea mays L.), soyabean (Glycine max L.) and wheat (Triticum spp.). Neither the energy (nectar) nor protein (pollen) needs of pollinating and other beneficial insects are being met sufficiently by the new, high‐intensity, agricultural landscape. Several potentially useful oilseed crops can be grown in the UMW, and many of these oilseeds are highly attractive to beneficial insects. Prior research showed that some of these oilseeds produced abundant nectar, but their corresponding values for pollen production are unknown. Accordingly, the aim of our research was to document pollen (and protein) production per unit area of twelve oilseed crops grown in Minnesota and associate these values with levels of beneficial insect visitation during anthesis. Our results show that oilseed crops such as camelina (Camelina sativa L.), flax (Linum usitatissimum L.) and pennycress (Thlaspi arvense L.) produce relatively little pollen (≤40 kg/ha); borage (Borago officinalis L.), calendula (Calendula officinalis L.), canola (Brassica napus L.), crambe (Crambe abyssianica Hochst) and cuphea (Cuphea viscosissima Jacq. × Cuphea lanceolata W. T. Aiton) produce bountiful pollen resources (50–150 kg/ha); and oilseed echium (Echium plantagineum L.) generates massive amounts of pollen (>400 kg/ha), about 50% of which is protein. Our study is unique in presenting a season‐long perspective of pollen production in alternative oilseed crops, a resource valuable to pollen‐feeding insects such as managed and wild bees. Diversification of UMW landscapes that includes alternative oilseed crops such as oilseed echium and cuphea can potentially provide a ready source of pollen and protein to help combat pollinator decline.     

Isolation of blood-brain barrier-crossing antibodies from a phage display library by competitive elution and their ability to penetrate the central nervous system

The blood-brain barrier (BBB) is a formidable obstacle for delivery of biologic therapeutics to central nervous system (CNS) targets. Whilst the BBB prevents passage of the vast majority of molecules, it also selectively transports a wide variety of molecules required to maintain brain homeostasis. Receptor-mediated transcytosis is one example of a macromolecule transport system that is employed by cells of the BBB to supply essential proteins to the brain and which can be utilized to deliver biologic payloads, such as antibodies, across the BBB. In this study, we performed phage display selections on the mouse brain endothelial cell line, bEND.3, to enrich for antibody single-chain variable fragments (scFvs) that could compete for binding with a known BBB-crossing antibody fragment, FC5. A number of these scFvs were converted to IgGs and characterized for their ability to bind to mouse, rat and human brain endothelial cells, and subsequent ability to transport across the BBB. We demonstrated that these newly identified BBB-targeting IgGs had increased brain exposure when delivered peripherally in mice and were also able to transport a biologically active molecule, interleukin-1 receptor antagonist (IL-1RA), into the CNS. The antagonism of the interleukin-1 system within the CNS can result in the relief of neuropathic pain. We demonstrated that the BBB-targeting IgGs were able to elicit an analgesic response in a mouse model of nerve ligation-induced hypersensitivity when fused to IL-1RA.     

Sialylation of intestinal microvillar membranes in newborn, sucking and weaned pigs

Affinity cytochemistry and biochemistry revealed distinctivetemporal changes in the expression of sialylated and compositionallyrelated membrane glycoconjugates in the pig small intestinebetween birth and weaning. The expression of membrane NeuAc2,6moieties, recognized by Sambucus nigra agglutinin-1, was highin newborn pigs, declined slightly during sucking and was verylow in weaned animals. Conversely, the expression of membraneNeuAc2r3 moieties, recognized by Maackia amurensis agglutinin-2,was low at birth but higher in sucking and weaned animals. Histobloodgroup O- and A-antigen expression was first detected in a minorityof sucking pigs, but was evident in all weaned pigs examined.Lactase glycoforms were isolated from solubilized microvillarmembranes of newborn and weaned pigs. The newborn (predominantly2,6-sialylated) and weaned (predominantly 1,2-fucosylated) glycoformsexhibited similar specific activity, indicating that postnatallactase decline in the pig intestine is unrelated to temporalchanges in membrane sialylation and fucosylation. fucosylation lactase lectins intestine sialylation     

Release of glutathione from erythrocytes and other markers of oxidative stress in carbon monoxide poisoning

Thom, Stephen R., Melissa Kang, Donald Fisher, and HarryIschiropoulos. Release of glutathione from erythrocytes and othermarkers of oxidative stress in carbon monoxide poisoning. J. Appl. Physiol. 82(5):1424-1432, 1997.Rats exposed to CO in a manner known to causeoxidative stress in brain exhibited a twofold increase in plasma levelsof oxidized proteins, thiobarbituric acid-reactive substances (TBARS),oxidized glutathione (GSSG), and reduced glutathione(GSH). Changes were neither directly related to hypoxicstress from carboxyhemoglobin nor significantly influenced bycirculating platelets or neutrophils. Treatment with the nitric oxidesynthase inhibitorN-nitro-L-arginine methylester inhibited elevations in GSH and GSSG but not changesin oxidized proteins or TBARS, suggesting that two oxidative mechanismsmay be operating in this model and that GSH and GSSG elevationsinvolved nitric oxide-derived oxidants. Elevations of blood GSH andGSSG occurred at different anatomic sites, indicating that no singleorgan was the source of the increased peptides. Animals that underwentexchange transfusion with a hemoglobin-containing saline solution didnot exhibit elevations in GSH and GSSG, suggesting that blood-bornecells released these peptides in response to oxidative stress. In invitro studies, erythrocytes, but not platelets and leukocytes,responded to oxidative stress from peroxynitrite by releasing GSH,whereas no release was observed in response to nitric oxide orsuperoxide. Glucose, maltose, and cytochalasin B, agents that protectextracellular components of the hexose transport protein complex fromoxidative stress, prevented GSH release. The data indicate that nitricoxide-derived oxidants are involved in CO-mediated oxidative stresswithin the vascular compartment and that elevations of severalcompounds may be useful for identifying exposures to CO likely toprecipitate brain injury.

     

Differential expression of tissue transglutaminase in human cells

Summary Tissue transglutaminase is an intracellular enzyme without established physiological function. Biochemically it can be detected in all organs, but no systematic in situ localization has been carried out so far. Here we report the immunohistochemical localization of transglutaminase in human tissues using an affinity purified, monospecific anti-human transglutaminase antibody. It is shown that the widespread organ distribution of the enzyme is the consequence of its occurrence in ubiquitous cell types such as endothelium and smooth muscle cells. Some organ-specific cell types express the enzyme constitutively (mesangial cells, renomedullary interstitial cells, thymic subcapsular epithelium, colonic pericryptal fibroblasts), while in others it seems to be induced either by external stimuli (epithelium of the female breast) or as part of their differentiation/maturation program (developing nephrons, enterocytes of the small intestine). The presence of tissue transglutaminase can be demonstrated in derivatives of all germ layers and in the trophoblast. The functional implications of these findings are presently unknown; however, based on its distribution the role of this enzyme in compartmentation and preservation of tissue integrity against stress may be suggested.Part of this work was presented at the symposium Transglutaminase and Protein Crosslinking Reactions (Noble Conference in Cellular and Molecular Biology, March 29–April 1, 1987, Miami, Fla.), and at the 1st International Symposium on Post-translational Modifications of Proteins and Ageing (Lacco Ameno d'Ischia, Naples, Italy, May 11–15, 1987)     

The mechanism of sugar uptake by sugarcane suspension cells

Sugarcane cell suspensions took up sugar from the medium at rates comparable to or greater than sugarcane tissue slices or plants in the field. This system offers an opportunity for the study of kinetic and energetic mechanisms of sugar transport in storage parenchyma-like cells in the absence of heterogeneity introduced by tissues. The following results were obtained: (a) The sugar uptake system was specific for hexoses; as previously proposed, sucrose was hydrolyzed by an extracellular invertase before the sugar moieties were taken up; no evidence for multiple sugar uptake systems was obtained. — (b) Uptake of the glucose-analog 3-O-methylglucose (3-OMG) reached a plateau value with an intracellular concentration higher than in the medium (approximately 15-fold). — (c) There was a balance of influx and efflux during steady state; the rate of exchange influx was lower than the rate of net influx; the K_m value was higher (70 M) than for net influx (24 M); the exchange efflux is proposed to be mediated by the same transport system with a K_m value of approximately 2.6 mM for internal 3-OMG; the rate of net efflux of hexoses was less than a third of the rate of exchange efflux. — (d) The uptake of hexoses proceeded as proton-symport with a stoichiometry of 0.87 H⁺ per sugar; during the onset of hexose transport there was a K⁺ exit of 0.94 K⁺ per sugar for charge compensation. (It was assumed that the real stoichiometries are 1 H⁺ and 1 K⁺ per sugar.) The K_m values for sugar transport and sugar-induced proton uptake were identical. Sucrose induced proton uptake only in the presence of cell wall invertase. — (e) There was no net proton uptake with 3-OMG by cells which were preloaded with glucose though there was significant sugar uptake. It is assumed, therefore, that the exit of hexose occurs together with protons. — (f) The protonmotive potential of sugarcane cells corresponded to about 120 mV: pH-gradient 1.1 units, membrane potential of-60 mV (these values increased if vacuolar pH and membrane potential were also considered). It was abolished by uncouplers, and the magnitude of the components depended on the external pH value. We present evidence for the operation of a proton-coupled sugar transport system in cell suspensions that were derived from, and have characteristics of, storage parenchyma. The quantitative rates of sugar transport suggest that the role of this transport system is not limiting for sugar storage.Abbreviations 3-OMG 3-O methylglucose - DMO 5,5-dimethyl-2, 4-oxazolidinedione - TPP tetraphenylphosphonium chloride - CCCP carbonyl cyanide, m-chlorophenylhydrozane