8,782 research outputs found
A comparison of the moss floras of Chile and New Zealand
No full textChile and New Zealand share a common stock of 181 species of mosses in 94 genera and 34 families. This number counts for 23.3% of the Chilean and 34.6% of the New Zealand moss flora. If only species with austral distribution are taken into account, the number is reduced to 113 species in common, which is 14.5% of the Chilean and 21.6% of the New Zealand moss flora. This correlation is interpreted in terms of long distance dispersal resp. the common phytogeographical background of both countries as parts of the palaoaustral floristic region and compared with disjunct moss floras of other continents as well as the presently available molecular data
Speech of Senator Frank E. Moss (D-Utah) delivered to the Western States Occupational Health seminar, Treasure Mountain Inn, Park City, Utah, by Douglas W. Owens, State Assistant to Senator Moss, on June 2, 1966
No full textTypescript draft (7 pages) of a speech by Utah Senator Frank E. Moss, delivered by his assistant, Douglas W. Owens, at a seminar on occupational health in Park City on 2 June 1966. The speech focused on federal efforts through the Public Health Service and its occupational health program
A Method For the Assay of Phosphatidylinositol-specific Phospholipase-d Activity In Serum
No full textA reproducible substrate for the assay of phosphatidylinositol-specific phospholipase D (PIPLD) can be prepared by extracting alkaline phosphatase from placental tissue with n-butanol under alkaline conditions. The alkaline phosphatase thus prepared retains its hydrophobic glycan phosphatidylinositol (GPI) anchor and aggregates into high M(r) forms. Incubation with serum hydrolyses the phosphate inositol linkage by PIPLD action, producing a less lipophilic, non-aggregated isoform of alkaline phosphatase. Three methods of measuring the amount of this isoform produced after a timed incubation with serum are described and compared: two types of phase partitioning systems, and electrophoresis and densitometry of the products after gradient-pore electrophoresis. All give comparable and reproducible measurements of PIPLD; however, the electrophoretic method is preferred for routine analysis
Statement of Senator Frank E. Moss (D-Utah) , NCTA Cablecasting seminar, Salt Lake City, Utah, February 29, 1968
No full textTypescript draft (8 pages) of a statement by Utah Senator Frank E. Moss made by telephone for a seminar on cable broadcasting held by the National Cable Television Association in Salt Lake City, Utah, on 29 February 1968. Also a copy of the printed schedule for the seminar; NCTA Membership Bulletin vol. 10, no.7 (Feb. 27, 1968); and a letter of the same date from NCTA President Frederick W. Ford
Occurrence of the neotropical moss Dicranella hilariana (Mont.) Mitt. in the Antarctic
No full textDicranella hilariana (Mont.) Mitt., a pan-neotropical moss species, is reported for the first time from the Antarctic botanical zone. It was found on geothermally heated ground near fumaroles on Visokoi, Candlemas and Bellingshausen Islands in the volcanic archipelago of the South Sandwich Islands. Dicranella recurvata Ochyra, Arts & Lewis-Smith, nom. nud., is reduced to synonymy with D. hilariana. The Antarctic plants of D. hilariana are briefly described and illustrated, including the rhizoidal tubers which have not previously been reported in this species. The global distribution of D. hilariana is briefly reviewed and mapped. It is suggested that the species reached the Antarctic via long-distance dispersal from South America by the prevailing strong westerly winds
Morphogenesis in the moss physcomitrella patens
No full textA method was developed for recording the development of moss protonema using time-lapse video microscopy. This has provided a detailed record of the time-course of development from spore germination to the production of gametophores. Detailed records of the growth of primary and secondary chloronema, the transition of primary
chloronema to caulonema, and the development of side-branches were obtained. Filaments were found to undergo the transition to caulonema earlier than previously
thought. The majority of caulonemas ide-branches were found to begin as chloronema and switch to caulonema after one or two cell cycles. The early cell divisions of bud
formation were found to follow a distinct pattern, which was upset by high concentrations of cytokinin and lanthanum. The response of caulonema apical cells to
polarotropic light was recorded and compared to the gravitropic response.
The time-lapse studies provided the basis for the further development of the quantitative analysis of protonemal branching patterns to include second and third
side-branches of a sub-apical cell, and transitional caulonema. Analysing side-branch patterns should allow the detection of developmental mechanisms underlying the
determination of side-branch fate. The potential of this method for assessing the effect of hormone treatments and for analysing more precisely mutant phenotypes was
explored. An analysis of bud spacing was carried out to determine if the formation of a bud on a filament was inhibitory to other buds forming on the same filament. It was found, to the contrary, that buds tended to form in clusters.
The hypothesis that the primary mode of action of cytokinin is an enhanced influx of calcium ions into the cell was investigated. Classical electrophysiology was used in
order to detect any change in membrane potential suggestive of ionic fluxes in response to cytokinin treatment. No definitive changes in membrane potential were detected in response to cytokinin. This appeared to rule out the involvement of voltage-regulated channels in cytokinin action. The effects of some inhibitors used in
studies of calcium on the moss protonemal system were examined. It is suggested that the concentrations commonly used had toxic effects that were not specific to calcium
channels. The ionophore A23187 was used to characterise the protonemal response to a sustained influx of calcium. Some mutant strains were found to have a differential
response to the ionophore. This may mean that they have mutations affecting their calcium regulatory system.
Two new techniques of imaging calcium were used in order to detect changes in intracellular calcium in response to cytokinin. A method was developed for loading the dual wavelength fluorescent dye Indo-1 into moss protonema using iontophoretic microinjection, and intracellular calcium was imaged using ratio-image technology. Wild-type moss and some mutant strains were also successfully transformed with the gene for apoaequorin, and calcium luminescence measured in response to cold-shock and plant hormones. Some different responsesto temperatures hock were apparent in
one of the transformed mutants. Preliminary experiments did not reveal any aequor independent calcium luminescence in response to cytokinin
Gradsteinia andicola : a remarkable aquatic moss from South America
No full textA new moss genus and species, Gradsteinia andicola, is described from the northern Andes of Colombia. It is an aquatic moss known sterile and characterized by 1) oblong or oblong-ovate, concave, cucullate and recurved-apiculate leaves with a very strong and variable costa that is basically single but commonly repeatedly branched and spurred from the base, giving the leaves a polycostate appearance; 2) thick-walled, porose and irregularly uni- to multistratose lamina cells; 3) bicellular axillary hairs; 4) the presence of incomplete limbidia; 5) the absence of paraphyllia, pseudoparaphyllia, central strand and alar cells. Until the sporophyte of Gradsteinia becomes known, this very distinct genus is tentatively placed in the family Donrichardsiaceae, based primarily upon the presence of variously multistratose leaf laminae and leaf areolation
An ecophysiological study on the moss hydrogoniuh fontanum from the Asir mountains, Saudi Arabia
No full textThe thesis describes a study on the ecophysiology of the moss Hydrogonium fontanum (C. Mail.) Jaeg., the dominant plant at a waterfall in Saudi Arabia. The influence of environmental variables and water stress on the growth, stress metabolite accumulation and phosphatase activities of the moss was studied in laboratory axenic culture along with observations and experiments conducted in the field. The variables chosen for growth experiments were light flux, flooding, nutrient concentrations and water stress. For phosphatase activities, the influence of temperature, pH, ions, water stress were studied. Differences were found in phosphatase activities for rhlzoids, protonema and leafy shoots of the moss and, therefore, the phosphomonoesterase (PMEase) and phosphodiesterase (PDEase) activities of these fractions were also investigated. H. fontanum was originally collected from the tufa-depositing waterfall (Water chemistry - 44 mg 1(^-1) Na, 44 mg 1(^-1) Ca). High Na and Ca had significant positive effect on yield of the protonema under the laboratory conditions. Low light intensity (10 µmol photon m(^-2) s(^-1)) decreased the yield, but high light intensity (90 µmol photon m(^-2) s(^-1)) increased the yield of the protonema. The moss showed no response to water stress in respect to praline accumulation. Protein content decreased significantly over 48 h with increase in water stress. The Influence of water stress was greater in terms of dry weight and chlorophyll content changes in protonema than in leafy shoots. The protonema was capable of using various organic P substrates as sources of phosphorus and showed both PMEase and PDEase activities. PMEase and PDEase activities were detectable in all moss fractions (rhizoids, protonema, leafy shoots). Laboratory grown material showed higher activities than field grown material. Rhizoids produced the highest PMEase and PDEase activities among the moss fractions. Some leafy shoots collected from the field had low phosphorus content with high phosphatase activities, while others had high phosphorus content with low phosphatase activities. Changes in phosphatase activities in batch culture were studied in relation to growth rate. PMEase activity was first evident when cellular P was 1.15% with low activity (0.117 µmol pNP mg d. wt(^-1) h(^-1)) and PDEase appeared 4 days later when cellular P was 0.54%. The activities increased up to day 12 after which the activities maintained this level. The optimum temperatures, measured over a period of 1 h, for PMEase and PDEase activities were 60 ºC and 65 ºC with pH optima of 5.5-6.0 and 6.4-6.8, respectively. Of the six ions tested, Ca, Zn and P had significant inhibitory effects on the activities at the highest concentration used (10 mM).Drying the moss decreases PMEase and PDEase activities by about 23% and 21% (5-d) and 3.7 and 2,8 times (3 months), respectively. Water stress (PEG treatment) also reduced significantly the activities of PMEase and PDEase with a greater effect on the activity of the latter. A brief comparison in PMEase activity using two different substrates p- nitrophenyl phosphate (pNPP) and 4-methylumbelliferyl phosphate (4-MUP) was made to investigate the pH optima and time course. PMEase activity measured using 250 µM 4-MUP was about 60% of that measured using the same concentration of pNPP
The moss Bryum argenteum var. muticum Brid. is well adapted to cope with high light in continental Antarctica
No full textThe net photosynthetic rate (NP), chlorophyll fluorescence, carotenoid content and chlorophyll content of the cosmopolitan moss Bryum argenteum were measured in the field at Botany Bay, southern Victoria Land, continental Antarctica (77°S). Comparisons were made between sun- and shade-adapted forms, and changes were followed as the moss emerged from under the snow and during exposure of shade and sun forms to ambient light. Shade forms had lower light compensation and saturation values for NP but little difference in maximal NP rates. Shade forms exposed to ambient light changed rapidly (within five days) towards the performance of the sun forms. Surprisingly, this change was not by acclimation of shoots but by the production of new shoots. Chlorophyll and carotenoid levels measured on a molar chlorophyll basis showed no difference between sun and shade forms and also little change during emergence. The constant molar relationship between carotenoids and chlorophyll plus the high levels of the xanthophyll cycle pigments suggest that protection of the chlorophyll antenna was constitutive. This is an adaptation to the very high light levels that occur when the plants are active in continental Antarctica and contrasts to the situation in more temperate areas where high light is normally avoided by desiccation
Inositol-specific phosphorilipase D activity in health and disease.
No full text1. We report the first demonstration of the pathophysiological importance and clinical applications of the relatively recently discovered circulating enzyme, phosphoinositol-specific phospholipase D. This enzyme is known to cleave the large variety of important cell-surface molecules linked to the cell membrane by glycan-phosphatidylinositol linkages (glycan- phosphatidylinositol anchors). 2. When measured in the sera of healthy individuals, phosphoinositol-specific phospholipase D activity was found to show a strong negative correlation with age, the degree of depreciation being greater than that measured for most other analytes. 3. Serum phosphoinositol- specific phospholipase D activity was considerably depressed in patients presenting with conditions leading to reduced liver synthetic reserve, such as hepatocellular carcinoma or liver cirrhosis caused by chronic viral hepatitis, and correlated with reduced albumin levels in these conditions, indicating that the liver is the site of phosphoinositol-specific phospholipase D synthesis and that phosphoinositol-specific phospholipase D may be used as an additional marker of liver synthetic reserve. 4. When measured in patients with acute liver disease, such as acute viral hepatitis, or in patients with bronchopneumonia, phosphoinositol-specific phospholipase D activity was found to be significantly raised, demonstrating features characteristic of an acute-phase reactant. 5. These findings indicate that, besides its pathophysiological importance, phosphoinositol-specific phospholipase D and the measurement of its activity in serum may have a useful place in the investigation of a range of clinical conditions, including tissue injury and inflammation
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