Cicuta bulbifera L. (Umbelliferae) in Alaska

Cited are distribution records for Alaska of Cicuta bulbifera L. It was discovered growing in the Nowitna National Wildlife Refuge in north central Alaska in 1984 and again in 1987. An earlier record is also known from near Fairbanks.     

New species of Astragalus (Leguminosae) from Mesa County, Colorado

Named and described is Astragalus debequaeus Welsh from Mesa County, Colorado.         

New taxa in miscellaneous families from Utah

Named are the following: Astragalus limnocharis Barneby var. tabulaeus Welsh var. nov., from the pass between Boulder Mountain and the Table Cliff Plateau, Garfield County, Utah; A. eremiticus Sheldon var. ampularioides Welsh var. nov. from Washington County, Utah; Lupinus argenteus Pursh var. moabensis Welsh var. nov., from southeastern Utah, validated by inclusion of a Latin diagnosis; Erigeron zothecinus Welsh sp. nov. described from moist alcoves along Lake Powell, eastern Kane County, Utah; Cleomella palmerana Jones var. goodrichii Welsh var. nov. described from Uintah County, Utah; Arabis vivariensis Welsh sp. nov. named from northeastern Uintah County, Utah; Draba kassii Welsh sp. nov. described from material taken in the Deep Creek Mountains, western Tooele County, Utah.     

North American types of Oxytropis DC. (Leguminosae) at The Natural History Museum and Royal Botanic Garden, England, with nomenclatural comments and a new variety

Specimens of Oxytropis in the herbaria of The Natural History Museum and Royal Botanic Garden were examined to interpret their role in nomenclature. This is the first attempt at a systematic overview of specimens so important in understanding the genus as it occurs in North America. The review of specimens at BM and K during the present research has resulted in realignment of names of some of the taxa. Oxytropis campestris var. gracils (A. Nelson) Barneby is recognized herein as being predated by O. campestris var. spicata Hook., O. sericea var. spicata (Hook.) Barneby is replaced by O. sericea var. speciosa (Torr. & A. Gray) Welsh comb. nov., and O. campestris var. terrae-novae (Fern.) Barneby is superseded by O. campestris var. minor (Hook.) Welsh comb. nov. One new taxon is proposed: Oxytropis deflexa (Pall.) DC. var. pulcherrima Welsh & A. Huber, var. nov. Lectotypes are designated for the following taxa: Astragalus retroflexus Pall. Oxytropis artica R. Br., O. artica var. α subumbellata Hook., O. arctica var. β uniflora Hook. O. campestris var. β sepciosa Torr & A. Gray, O. campestris var. ξ melanocephala Hook., O. campestris var. δ spincata Hook., O. multiceps var. minor A. Gray, O. splendens Douglas ex Hook., O. splendens β richardsonii Hook., O. uralensis β subsucculenta Hook., and O. uralensis γ minor Hook.     

Chloride and potassium channels in cystic fibrosis airway epithelia

Cystic fibrosis, the most common lethal genetic disease in Caucasians, is characterized by a decreased permeability in sweat gland duct and airway epithelia. In sweat duct epithelium, a decreased Cl- permeability accounts for the abnormally increased salt content of sweat. In airway epithelia a decreased Cl- permeability, and possibly increased sodium absorption, may account for the abnormal respiratory tract fluid. The Cl- impermeability has been localized to the apical membrane of cystic fibrosis airway epithelial cells. The finding that hormonally regulated Cl- channels make the apical membrane Cl- permeable in normal airway epithelial cells suggested abnormal Cl- channel function in cystic fibrosis. Here we report that excised, cell-free patches of membrane from cystic fibrosis epithelial cells contain Cl- channels that have the same conductive properties as Cl- channels from normal cells. However, Cl- channels from cystic fibrosis cells did not open when they were attached to the cell. These findings suggest defective regulation of Cl- channels in cystic fibrosis epithelia; to begin to address this issue, we performed two studies. First, we found that isoprenaline, which stimulates Cl- secretion, increases cellular levels of cyclic AMP in a similar manner in cystic fibrosis and non-cystic fibrosis epithelial cells. Second, we show that adrenergic agonists open calcium-activated potassium channels, indirectly suggesting that calcium-dependent stimulus-response coupling is intact in cystic fibrosis. These data suggest defective regulation of Cl- channels at a site distal to cAMP accumulation.     

Cyclic AMP-dependent protein kinase opens chloride channels in normal but not cystic fibrosis airway epithelium

Chloride (Cl-) secretion by the airway epithelium regulates, in part, the quantity and composition of the respiratory tract fluid, thereby facilitating mucociliary clearance. The rate of Cl- secretion is controlled by apical membrane Cl- channels. Apical Cl- channels are opened and Cl- secretion is stimulated by a variety of hormones and neurotransmitters that increase intracellular levels of cyclic AMP (cAMP). In cystic fibrosis (CF), a common lethal genetic disease of Caucasians, airway, sweat-gland duct, secretory-coil and possibly other epithelia are anion impermeable. This abnormality may explain several of the clinical manifestations of the disease. The Cl- impermeability in CF-airway epithelia has been localized to the apical cell membrane, where regulation of Cl- channels is abnormal: hormonal secretagogues stimulate cAMP accumulation appropriately but Cl- channels fail to open. Here we report that the purified catalytic subunit of cAMP-dependent protein kinase plus ATP opens Cl- channels in excised, cell-free patches of membrane from normal cells, but fails to open Cl- channels in CF cells. These results indicate that in normal cells, the cAMP-dependent protein kinase phosphorylates the Cl- channel or an associated regulatory protein, causing the channel to open. The failure of CF Cl- channels to open suggests a defect either in the channel or in such an associated regulatory protein.