The nature of the "nuclear cap" and nuclear behavior in Phytophthora infestans

1973 ◽  
Vol 51 (10) ◽  
pp. 1983-1984 ◽  
Author(s):  
Bela Sivak
Keyword(s):  
Phytophthora Infestans ◽  
Nuclear Division ◽  
Major Constituent ◽  
Supporting Evidence ◽  
Nuclear Behavior

The nature of the "nuclear cap" of sporangial nuclei of Phytophthora infestans was studied after treatment with 1.0 N HCl, separate digestions with RNase and DNase, and staining with Feulgen and orcein stains. The results strongly support the conclusion that DNA is a major constituent of the "nuclear cap." Although they provide some supporting evidence for the conclusion that sporangia become multinucleate through migration of nuclei into them, the results also indicate that nuclear division may take place within young sporangia.

Effect of light intensity on the ultrastructure of the filamentous cyanobacterium, Anabaena variabilis

1988 ◽  
Vol 46 ◽  
pp. 300-301
Author(s):  
C. S. Bricker ◽  
S. R. Barnum ◽  
B. Huang ◽  
J. G. Jaworskl
Keyword(s):  
Fatty Acid ◽  
Light Intensity ◽  
Acid Content ◽  
Fatty Acid Content ◽  
Anabaena Variabilis ◽  
Chloroplast Envelope ◽  
Major Constituent ◽  
Filamentous Cyanobacterium ◽  
Photosynthetic Membrane ◽  
Effect Of Light

Cyanobacteria are Gram negative prokaryotes that are capable of oxygenic photosynthesis. Although there are many similarities between eukaryotes and cyanobacteria in electron transfer and phosphorylation during photosynthesis, there are two features of the photosynthetic apparatus in cyanobacteria which distinguishes them from plants. Cyanobacteria contain phycobiliproteins organized in phycobilisomes on the surface of photosynthetic membrane. Another difference is in the organization of the photosynthetic membranes. Instead of stacked thylakolds within a chloroplast envelope membrane, as seen In eukaryotes, IntracytopIasmlc membranes generally are arranged in three to six concentric layers. Environmental factors such as temperature, nutrition and light fluency can significantly affect the physiology and morphology of cells. The effect of light Intensity shifts on the ultrastructure of Internal membrane in Anabaena variabilis grown under controlled environmental conditions was examined. Since a major constituent of cyanobacterial thylakolds are lipids, the fatty acid content also was measured and correlated with uItrastructural changes. The regulation of fatty acid synthesis in cyanobacteria ultimately can be studied if the fatty acid content can be manipulated.

The Effect of Benzene on Bluegill Olfactory Lamellae

1985 ◽  
Vol 43 ◽  
pp. 574-575
Author(s):  
D.R. Mattie ◽  
J.W. Fisher
Keyword(s):  
Surface Morphology ◽  
Soluble Fraction ◽  
Lepomis Macrochirus ◽  
Sublethal Concentration ◽  
Water Soluble ◽  
Major Constituent ◽  
Jet Fuels ◽  
Aquatic Biota ◽  
Normal Surface ◽  
Cacodylate Buffer

Jet fuels such as JP-4 can be introduced into the environment and come in contact with aquatic biota in several ways. Studies in this laboratory have demonstrated JP-4 toxicity to fish. Benzene is the major constituent of the water soluble fraction of JP-4. The normal surface morphology of bluegill olfactory lamellae was examined in conjunction with electrophysiology experiments. There was no information regarding the ultrastructural and physiological responses of the olfactory epithelium of bluegills to acute benzene exposure.The purpose of this investigation was to determine the effects of benzene on the surface morphology of the nasal rosettes of the bluegill sunfish (Lepomis macrochirus). Bluegills were exposed to a sublethal concentration of 7.7±0.2ppm (+S.E.M.) benzene for five, ten or fourteen days. Nasal rosettes were fixed in 2.5% glutaraldehyde and 2.0% paraformaldehyde in 0.1M cacodylate buffer (pH 7.4) containing 1.25mM calcium chloride. Specimens were processed for scanning electron microscopy.

The value of Electron Microscope studies of imperfect natural diamonds

1990 ◽  
Vol 48 (4) ◽  
pp. 194-195
Author(s):  
J C Walmsley ◽  
A R Lang
Keyword(s):  
Electron Microscope ◽  
Classification Scheme ◽  
Natural Diamond ◽  
Sudden Change ◽  
Growth Conditions ◽  
Diamond Growth ◽  
Major Constituent ◽  
Natural Diamonds ◽  
Type Ia ◽  
Platelet Defects

Interest in the defects and impurities in natural diamond, which are found in even the most perfect stone, is driven by the fact that diamond growth occurs at a depth of over 120Km. They display characteristics associated with their origin and their journey through the mantle to the surface of the Earth. An optical classification scheme for diamond exists based largely on the presence and segregation of nitrogen. For example type Ia, which includes 98% of all natural diamonds, contain nitrogen aggregated into small non-paramagnetic clusters and usually contain sub-micrometre platelet defects on {100} planes. Numerous transmission electron microscope (TEM) studies of these platelets and associated features have been made e.g. . Some diamonds, however, contain imperfections and impurities that place them outside this main classification scheme. Two such types are described.First, coated-diamonds which possess gem quality cores enclosed by a rind that is rich in submicrometre sized mineral inclusions. The transition from core to coat is quite sharp indicating a sudden change in growth conditions, Figure 1. As part of a TEM study of the inclusions apatite has been identified as a major constituent of the impurity present in many inclusion cavities, Figure 2.

Exposure of protein VP7 on the surface of bluetongue virus

1990 ◽  
Vol 48 (3) ◽  
pp. 600-601
Author(s):  
A.D. Hyatt
Keyword(s):  
Bluetongue Virus ◽  
Structural Proteins ◽  
Major Constituent ◽  
Outer Coat ◽  
Virus Particles ◽  
Antibody Recognition ◽  
The Core ◽  
The Family ◽  
Electron Microscopical ◽  
Physical Accessibility

Bluetongue virus (BTV) is the type species os the genus orbivirus in the family Reoviridae. The virus has a fibrillar outer coat containing two major structural proteins VP2 and VP5 which surround an icosahedral core. The core contains two major proteins VP3 and VP7 and three minor proteins VP1, VP4 and VP6. Recent evidence has indicated that the core comprises a neucleoprotein center which is surrounded by two protein layers; VP7, a major constituent of capsomeres comprises the outer and VP3 the inner layer of the core . Antibodies to VP7 are currently used in enzyme-linked immunosorbant assays and immuno-electron microscopical (JEM) tests for the detection of BTV. The tests involve the antibody recognition of VP7 on virus particles. In an attempt to understand how complete viruses can interact with antibodies to VP7 various antibody types and methodologies were utilized to determine the physical accessibility of the core to the external environment.

Text Comprehension: Graphic Organizers to the Rescue

2009 ◽  
Vol 10 (3) ◽  
pp. 82-89
Author(s):  
Janet L. Proly ◽  
Jessica Rivers ◽  
Jamie Schwartz
Keyword(s):  
Reading Comprehension ◽  
Text Comprehension ◽  
Graphic Organizers ◽  
Expository Text ◽  
Supporting Evidence

Abstract Graphic organizers are a research based strategy used for facilitating the reading comprehension of expository text. This strategy will be defined and the evolution and supporting evidence for the use of graphic organizers will be discussed. Various types of graphic organizers and resources for SLPs and other educators will also be discussed.

In vitro schistosomicidal activity of Usnea steineri extract and its major constituent (+)-usnic acid against Schistosoma mansoni

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
AIO Salloum ◽  
R Lucarini ◽  
MG Tozatti ◽  
J Medeiros ◽  
MLA Silva ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Usnic Acid ◽  
Major Constituent

Experimentally increased costs of parental care are shunted to offspring in species with extended care

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Life History ◽  
Parental Care ◽  
Total Duration ◽  
Bird Species ◽  
Life History Strategy ◽  
Experimental Treatment ◽  
Cost Of Care ◽  
Adult Survival ◽  
Supporting Evidence ◽  
Trade Offs

Biparental care systems are a valuable model to examine conflict, cooperation, and coordination between unrelated individuals, as the product of the interactions between the parents influences the fitness of both individuals. A common experimental technique for testing coordinated responses to changes in the costs of parental care is to temporarily handicap one parent, inducing a higher cost of providing care. However, dissimilarity in experimental designs of these studies has hindered interspecific comparisons of the patterns of cost distribution between parents and offspring. Here we apply a comparative experimental approach by handicapping a parent at nests of five bird species using the same experimental treatment. In some species, a decrease in care by a handicapped parent was compensated by its partner, while in others the increased costs of care were shunted to the offspring. Parental responses to an increased cost of care primarily depended on the total duration of care that offspring require. However, life history pace (i.e., adult survival and fecundity) did not influence parental decisions when faced with a higher cost of caring. Our study highlights that a greater attention to intergenerational trade-offs is warranted, particularly in species with a large burden of parental care. Moreover, we demonstrate that parental care decisions may be weighed more against physiological workload constraints than against future prospects of reproduction, supporting evidence that avian species may devote comparable amounts of energy into survival, regardless of life history strategy.

RACIAL STEREOTYPING OF HOMO SAPIENS AFRICANUS: A REVIEW OF ITS MYTH AND IMPACT ON DEVELOPMENTAL CAPACITY

2016 ◽  
Vol 45 (2) ◽  
pp. 49-71 ◽  
Author(s):  
Seth Oppong
Keyword(s):  
Immanuel Kant ◽  
David Hume ◽  
Negative Impact ◽  
Homo Sapiens ◽  
Supporting Evidence ◽  
White People ◽  
Negative Stereotypes ◽  
Initial Errors ◽  
Developmental Capacity ◽  
Lower Intelligence

Generally, negatives stereotypes have been shown to have negative impact on performance members of a social group that is the target of the stereotype (Schmader, Johns and Forbes 2008; Steele and Aronson, 1995). It is against the background of this evidence that this paper argues that the negative stereotypes of perceived lower intelligence held against Africans has similar impact on the general development of the continent. This paper seeks to challenge this stereotype by tracing the source of this negative stereotype to David Hume and Immanuel Kant and showing the initial errors they committed which have influenced social science knowledge about race relations. Hume and Kant argue that Africans are naturally inferior to white or are less intelligent and support their thesis with their contrived evidence that there has never been any civilized nation other than those developed by white people nor any African scholars of eminence. Drawing on Anton Wilhelm Amo’s negligence-ignorance thesis, this paper shows the Hume-Kantian argument and the supporting evidence to be fallacious. 

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