Effects of SO2, O3, and SO2 and O3 in combination on photosynthesis and ultrastructure of two lichen species

1987 ◽  
Vol 65 (9) ◽  
pp. 1806-1818 ◽  
Author(s):  
Sharon Eversman ◽  
Lorene L. Sigal
Keyword(s):  
Electron Micrographs ◽  
Lichen Species ◽  
Ultrastructural Changes ◽  
Starch Grains ◽  
Low Concentrations ◽  
Ultrastructural Damage ◽  
Flavoparmelia Caperata ◽  
Umbilicaria Mammulata

Flavoparmelia caperata (L.) Hale and Umbilicaria mammulata (Ach.) Tuck, were exposed to 262 μg SO2 m−3, 59 μg O3 m−3, and 262 μg SO2 m−3 in combination with 59 μg O3 m−3 for 20 h over a 5-day period. Photosynthesis and ultrastructural observations were made after 12 and 20 h. At these low concentrations of pollutants, ultrastructural changes preceded and accompanied decreases in photosynthesis rates. Ozone was more phytotoxic than SO2. Ultrastructural damage was least with SO2 and greater and very similar with O3 and the combination of O3 and SO2. Photosynthetic data showed that SO2 ameliorates effects of O3. Electron micrographs showed increased accumulation of starch and cavity space around starch grains in the chloroplast and increased lipids in the cytoplasm in F. caperata; there was some increased starch in U. mammulata, but alterations were primarily in increased chloroplast opacity. Photosynthesis of U. mammulata was more sensitive to the pollutants than that of F. caperata. Ultrastructural damage was greater when samples were stored in the light than when they were stored in the dark between fumigations. The study shows that species vary in their responses to pollutants and that combinations of pollutants may give results different from those obtained with single pollutants.

Influence de la température et de la durée d'un traitement cryoprotecteur sur la résistance au froid de plantules de blé. Étude ultrastructurale des ébauches foliaires

1983 ◽  
Vol 61 (4) ◽  
pp. 1025-1039 ◽  
Author(s):  
C. M. Gazeau
Keyword(s):  
Endoplasmic Reticulum ◽  
Treatment Period ◽  
Day Treatment ◽  
Leaf Primordia ◽  
Ultrastructural Changes ◽  
Distilled Water ◽  
Wheat Seedlings ◽  
Starch Grains ◽  
Different Temperatures ◽  
Protective Treatment

Wheat seedlings were treated at different temperatures and for various periods of time with a cold-protective substance, composed of a mixture of glycerol, dimethylsulfoxide, and saccharose. When the treatment was done at 20 °C, slight ultrastructural changes appeared in leaf primordia as soon as day 1. Thus numbers of lipid globules increased significantly. When the treatment period was increased to 4 days, numbers of starch grains increased, and there was a marked enlargement of mitochondria and plasts. When the treatment was done at 2 °C, cytoplasmic alterations occurred later than at 20 °C. After a 4-day treatment, they were similar to changes induced at 20 °C. When the treatment period was increased to 12 days, dictyosomes were markedly altered. They clustered close to the nucleus in two or three groups and gave rise to numerous pale vesicles with various shapes and sizes. Around each cluster of such vesicles, there gathered many endoplasmic reticulum vesicles and other organelles (mitochondria, plasts, microbodies, vacuoles). A further cooling of 1 °C/min, down to −15 or −30 °C, enhanced these phenomena. After the seedlings were warmed up to 20 °C in distilled water, the changes induced by the frost-protective treatment and then by freezing were shown to be reversible. [Journal translation]

scholarly journals Ultrastructural Changes in Articular Cartilages of Immature Beagle Dogs Dosed with Difloxacin, a Fluoroquinolone

1992 ◽  
Vol 29 (3) ◽  
pp. 230-238 ◽  
Author(s):  
J. E. Burkhardt ◽  
M. A. Hill ◽  
J. J. Turek ◽  
W. W. Carlton
Keyword(s):  
Extracellular Matrix ◽  
Body Weight ◽  
Electron Micrographs ◽  
Collagen Fibrils ◽  
Ultrastructural Changes ◽  
Pericellular Matrix ◽  
Skeletally Immature ◽  
Beagle Dogs ◽  
Cross Sectional ◽  
Articular Cartilages

The ultrastructural features of quinolone-induced arthropathy were studied in' the humeral and femoral heads of nine skeletally immature Beagle dogs (3 months old) that were dosed orally with difloxacin at 300 mg/kg body weight and euthanatized 24, 36, or 48 hours later in groups of three. Three age-matched dogs were given a placebo and euthanatized after 48 hours. Mitochondria in chondrocytes had significantly greater cross-sectional areas ( P < 0.05) in electron micrographs from dogs euthanatized after 48 hours of treatment than did those in other groups. There was also a significantly greater percentage of chondrocytes with swollen mitochondria in treated dogs than in the controls ( P < 0.05). These changes preceded the necrosis observed in some chondrocytes in the dogs of the 48-hour group. Disruption of extracellular matrix was first observed in the pericellular matrix of necrotic chondrocytes, indicating that this change was secondary to the changes in chondrocytes. Fissures within cartilages apparently resulted from the loss of the normal association of proteoglycans with collagen fibrils.

The ultrastructure and metabolism of ejaculated tammar wallaby sperm are impaired by swim-up procedures when compared with sperm from the cauda epididymidis

1999 ◽  
Vol 11 (5) ◽  
pp. 263 ◽  
Author(s):  
R. N. Murdoch ◽  
R. C. Jones ◽  
M. Wade ◽  
M. Lin
Keyword(s):  
Tammar Wallaby ◽  
Ultrastructural Changes ◽  
Intracellular Accumulation ◽  
Epididymal Sperm ◽  
Metabolism Rate ◽  
Subsequent Exposure ◽  
Ultrastructural Damage ◽  
Metabolic Properties ◽  
Cauda Epididymidis ◽  
Induced Changes

The metabolism, rate of intracellular accumulation of sugars, motility and ultrastructure of ejaculated tammar sperm were impaired by swim-up into artificial media, particularly when the cells were subsequently exposed to N-acetyl-D-glucosamine (NAG). The inclusion of hyaluronate, serum albumin, catalase or Desferal in swim-up media helped prevent deterioration of sperm motility, but failed to prevent detrimental NAG-induced metabolic and ultrastructural changes. However, the sperm were unavoidably diluted during swim-up into artificial media and their behavioural properties were modified by dilution. Thus, sperm collected from the cauda epididymidis were immotile and their rate of oxygen uptake was low in undiluted caudal epididymal semen (CES). Nevertheless, these sperm were viable, and vigorous motility was induced by 5- to 50-fold dilution in Krebs-Ringer phosphate (KRP). Sperm respiration also dramatically increased with moderate dilution (5- or 15-fold) in KRP, but decreased again at higher rates (50-fold). This suggested that motility and the metabolic properties of tammar sperm are modified both by dilution and on leaving the suppressing conditions of the epididymis. Diluted tammar epididymal sperm also displayed a Pasteur effect, but rapidly lost capacity for motility in an oxygen-depleted atmosphere. It was concluded hat swim-up procedures compromise ejaculated tammar sperm by promoting dilution-induced changes. This may alter the permeability of the membrane with loss of the enzymes that process the ammonia generated during the metabolism of NAG in seminal plasma. Subsequent exposure to NAG further promotes ultrastructural damage culminating in loss of viability.

scholarly journals Role of Crop Load in Chloroplast Ultra-structure and Zonal Chlorosis, a Physiological Disorder in ‘Honeycrisp’ Apple Trees

HortScience ◽  
2008 ◽  
Vol 43 (6) ◽  
pp. 1819-1822 ◽  
Author(s):  
Teresa Eileen Snyder-Leiby ◽  
Shixiong Wang
Keyword(s):  
Membrane Structure ◽  
Potato Leafhopper ◽  
Ultrastructural Changes ◽  
Apple Cultivar ◽  
Physiological Disorder ◽  
Crop Load ◽  
Starch Grains ◽  
Transmission Electron ◽  
Starch Grain

‘Honeycrisp’ is a relatively new apple cultivar (Malus ×domestica Borkh.) with a unique crisp fruit texture that makes it highly desirable. However, the leaves often develop a zonal chlorosis that resembles potato leafhopper damage. Other researchers have determined that the symptoms correlate with decreasing crop load rather than leafhopper damage. This study investigates the possibility that the zonal chlorosis is related to the buildup of starch grains causing rupture of chloroplasts. Transmission electron microscopy was used to document ultrastructural changes in chloroplasts in trees with three different crop loads from the beginning of the season to the end of the season. In trees with extremely low crop loads, we observed abnormalities of chloroplast membrane structure and accumulation of larger and more numerous starch grains. These appear before the appearance of chlorotic symptoms. By early August, the chloroplasts from chlorotic regions of leaves on trees with light crop loads are completely disrupted and abnormally large starch grains are found in place of chloroplasts. As the season progresses, trees with moderate and heavy crop loads showed less severe chloroplast disruption and smaller starch grain accumulation than trees with light crop load.

scholarly journals Host plant specificity of corticolous lichens in urban and suburban New Amsterdam, Berbice, Guyana

2021 ◽  
Vol 14 (1) ◽  
pp. 101-108
Author(s):  
Bebe Raazia Bacchus ◽  
Phillip N.B. Da Silva
Keyword(s):  
Host Plant ◽  
Cocos Nucifera ◽  
Mangifera Indica ◽  
Lichen Species ◽  
New Amsterdam ◽  
Host Trees ◽  
Host Plant Specificity ◽  
Crustose Lichens ◽  
Flavoparmelia Caperata ◽  
Swietenia Mahagoni

In this study, host plant - lichen specificity was investigated. Data was collected from 1000m2 sampling plots at each of four locations with an established 50m x 20m plot at each site. Forty-one trees from across five species were examined using (10cm by 50cm) ladder quadrats on tree trunks (N, S, E, W) at 150cm height. A total of 14978 individual lichens were identified that yielded 10 families, 13 genera and 18 species. Swietenia mahagoni showed the highest average corticolous lichen species composition, followed by Terminalia catappa and Melicoccus bijugales respectively. Cocos nucifera had a higher average species recorded than Mangifera indica. Crustose lichens were the most prominent corticolous lichens observed (61%) with the most individuals in Graphidaceae and Arthoniaceae. Foliose lichens (28%) showed the most abundance in Parmeliaceae, Caliciaceae and Collemataceae. Of the taxa recorded, 22.2% were restricted to specific trees. C. parasitica, H. laevigata, U. cornuta were restricted to S. mahagoni. D. applanata was restricted to C. nucifera. 22.2% of recorded species were found on all of the tree hosts that were examined. Bacidia laurocerasi, Flavoparmelia caperata, Flavoparmelia soredians and Graphina anguina. S. mahagoni hosted 88.9% of all recorded species. Swietenia mahagoni showed the highest average of recorded corticolous lichen species of all host trees with 7.58. Mangifera indica showed the lowest average with 4. The maximum number of species (10) was recorded on one S. mahagoni tree

scholarly journals Effects of PEG-Coated Silver and Gold Nanoparticles on Spirulina platensis Biomass during Its Growth in a Closed System

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 717
Author(s):  
Liliana Cepoi ◽  
Inga Zinicovscaia ◽  
Ludmila Rudi ◽  
Tatiana Chiriac ◽  
Ion Rotari ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Spirulina Platensis ◽  
Biochemical Composition ◽  
Industrial Applications ◽  
Ultrastructural Changes ◽  
Cultivation Medium ◽  
Silver And Gold Nanoparticles ◽  
Low Concentrations ◽  
Negative Effect ◽  
High Concentrations

Silver and gold nanoparticles are promising tools for medical and industrial applications; therefore, their ecotoxicity should be carefully examined. There are many publications that discuss their effects at high concentrations on various organisms, while the effects of low doses have not been sufficiently investigated. In this paper, the effects of low concentrations of silver (12 nm) and gold (4.7 nm) nanoparticles coated with polyethylene glycol on Spirulina platensis biomass growth, biochemical composition, and antioxidant activity were investigated. The spirulina cultivation medium was supplemented with nanoparticles in the concentration range of 0.025–0.5 µM. The given concentrations stimulated spirulina biomass, but the content of proteins, carbohydrates, and auxiliary pigments was insignificantly affected by the presence of nanoparticles in the cultivation medium. Gold nanoparticles at a concentration of 0.5 µM produced a pronounced effect on the lipid content. Transmission electron microscope images demonstrated that the nanoparticles penetrate inside the cells and cause ultrastructural changes. The nanoparticles were characterized using several well-known techniques. The results confirmed a negative effect of low concentrations of metal nanoparticles on spirulina. This effect could be indiscernible when studying the biomass viability, but determination of the ultrastructure of the cell and the biochemical composition of the biomass could reveal it.

scholarly journals Geotropic Response of Wheat Coleoptiles in Absence of Amyloplast Starch

1966 ◽  
Vol 49 (5) ◽  
pp. 1065-1086 ◽  
Author(s):  
Barbara Gillespie Pickard ◽  
Kenneth V. Thimann
Keyword(s):  
Electron Micrographs ◽  
Triticum Durum ◽  
Asymmetric Distribution ◽  
Ordinary Sense ◽  
Starch Grains ◽  
Fixed Material ◽  
Show Evidence

Young coleoptiles of wheat (Triticum durum var. Henry), depleted of amyloplast starch by incubation at 30°C with gibberellin plus kinetin, retained their geotropic responsiveness. Depleted coleoptiles curved upward more slowly than controls, but this was commensurate with their slower growth. The ratio of curvature to growth was about 50° per mm of elongation in both cases. Newly excised coleoptiles, though containing much more starch than incubated controls, curved only about 25° per mm. The tissue treated in gibberellin plus kinetin appeared to contain no starch when examined (a) freshly squashed, (b) as fixed material sectioned thin and stained by the PAS procedure, and (c) as electron micrographs. Shrunken, starch-free amyloplasts could be identified in certain regions, but these did not show evidence of asymmetric distribution under the influence of gravity. The possibilities that other organelles function as statoliths are considered, and it is concluded not only that georeception is independent of starch grains, but further that it may not be due to statoliths at all in an ordinary sense.

Structural Changes in Animal Lungs Exposed to Low Concentrations of Ozone

1972 ◽  
Vol 30 ◽  
pp. 98-99
Author(s):  
E.S. Boatman ◽  
S. Sato ◽  
R. Frank
Keyword(s):  
Respiratory System ◽  
Alveolar Macrophages ◽  
Structural Changes ◽  
Ultrastructural Changes ◽  
Peripheral Airways ◽  
Low Concentrations

There is considerable interest and speculation about the possible effects of ozone on the function and structure of the lung. Evidence is accumulating that ozone attacks the respiratory system at many levels including the larger more central airways, the smaller peripheral airways, components of the blood-air barrier and alveolar macrophages.The present study is concerned with the functional, morphological, and ultrastructural changes in the respiratory system of animals exposed to low concentrations (either 0.25, 0.5, or 1.0 ppm) of O3 for 3 hours. Both cats and rabbits were used.

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