Onset ofTlx-3 expression in the chick cerebellar cortex correlates with the morphological development of fissures and delineates a posterior transverse boundary

2002 ◽  
Vol 448 (2) ◽  
pp. 138-149 ◽  
Author(s):  
Cairine Logan ◽  
Cassie Millar ◽  
Vinay Bharadia ◽  
Katherine Rouleau
Keyword(s):  
Cerebellar Cortex ◽  
Morphological Development ◽  
Transverse Boundary

Scanning Electron Microscopy and x-ray analysis of microparticles and early hydration effects

1995 ◽  
Vol 53 ◽  
pp. 692-693
Author(s):  
Yun Lu ◽  
David C. Joy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Morphological Development ◽  
Early Hydration ◽  
X Ray ◽  
Blended Cements ◽  
Powder Particles ◽  
Chemical Wastes ◽  
Scanning Electron

High resolution scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) were performed to investigate microparticles in blended cements and their hydration products containing sodium-rich chemical wastes. The physical appearance of powder particles and the morphological development at different hydration stages were characterized by using high resolution SEM Hitachi S-900 and by SEM S-800 with a EDX spectrometer. Microparticles were dispersed on the sample holder and glued by 1% palomino solution. Hydrated bulk samples were dehydrated by acetone and mounted on the holder by silver paste. Both fracture surfaces and flat cutting sections of hydrating samples were prepared and examined. Some specimens were coated with an 3 nm thick Au-Pd or Cr layer to provide good conducting surfaces. For high resolution SEM S-900 observations the accelerating voltage of electrons was 1-2 KeV to protect the electron charging. Microchemical analyses were carried out by S800/EDS equipped with a LINK detector of take-off angle =40°.

SEM study of the morphological effects of kinetin and zeatin on the growth and development of the apical meristem in wheat

1995 ◽  
Vol 53 ◽  
pp. 978-979
Author(s):  
G. M. Hutchins ◽  
J. S. Gardner
Keyword(s):  
Growth And Development ◽  
Furfuryl Alcohol ◽  
Apical Meristem ◽  
Plant Cells ◽  
Triticum Aestivum L ◽  
Morphological Development ◽  
Naturally Occurring ◽  
Chinese Spring Wheat ◽  
Sem Study ◽  
Moist Environment

Cytokinins are plant hormones that play a large and incompletely understood role in the life-cycle of plants. The goal of this study was to determine what roles cytokinins play in the morphological development of wheat. To achieve any real success in altering the development and growth of wheat, the cytokinins must be applied directly to the apical meristem, or spike of the plant. It is in this region that the plant cells are actively undergoing mitosis. Kinetin and Zeatin were the two cytokinins chosen for this experiment. Kinetin is an artificial hormone that was originally extracted from old or heated DNA. Kinetin is easily made from the reaction of adenine and furfuryl alcohol. Zeatin is a naturally occurring hormone found in corn, wheat, and many other plants.Chinese Spring Wheat (Triticum aestivum L.) was used for this experiment. Prior to planting, the seeds were germinated in a moist environment for 72 hours.

Intestinal microbiota balance modulates host susceptibility to infection with enteric pathogenss

2007 ◽  
Vol 30 (4) ◽  
pp. 93
Author(s):  
I Sekirov ◽  
N Tam ◽  
M Robertson ◽  
C Lupp ◽  
B Finlay
Keyword(s):  
Intestinal Microbiota ◽  
Small Animal ◽  
Host Susceptibility ◽  
Morphological Development ◽  
Future Design ◽  
Susceptibility To Infection ◽  
Colonic Microbiota ◽  
Food Borne ◽  
Serovar Typhimurium ◽  
Intestinal Pathogens

Background: During our lifetimes we develop a very complex set of interactions with the multitude of microorganisms colonizing our bodies. In the gastrointestinal system, the microbiota is highly important for morphological development, nutrition, and protection against infectious diseases. The gastrointestinal pathogens, enterohemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC) and Salmonella enterica serovar Typhimurium (ST) are food-borne pathogens that cause much morbidity and mortality worldwide. Citrobacter rodentium (Cr) is a mouse pathogen that is used in small animal models to mimic EHEC and EPEC infections. Methods: We began to characterize the contribution of intestinal microbiota to the progression of these infections. Two main phyla comprise the majority of mouse intestinal microbiota: Bacteroidetes and Firmicutes. Bacteria from a number of additional phyla are also present in smaller numbers; among them γ-Proteobacteria class, belonging to Proteobacteria phylum, is note-worthy as this class harbours many intestinal pathogens, such as ST and Cr. The mouse intestinal microbiota was perturbed using tetracycline (Tet) and streptomycin (Sm) to increase the proportion of Bacteroidetes in the colonic microbiota, and using vancomycin (Vanc) to create a predominance of Firmicutes. The mice with this perturbed microbiota were infected with ST to investigate the resultant pathology and virulence characteristics, and any additional shifts in microbiota as a result of infection. Results: Treatment of mice with Sm and Vanc was found to decrease the resistance of mice to colonization with ST, while Tet-treated mice exhibited unchanged colonization resistance. Treatment of mice with gradually increasing doses of Sm, which gradually augmented the proportion of CFB bacteria in the microbiota, resulted in progressively increasing colonization of mice by ST, as well as a step-wise increase in the ST-induced typhlitis, associated with higher levels of inflammatory markers IL-6 and KC. The increasing levels of ST colonization following both Sm and Vanc treatment were associated with an increase in the proportion of γ-Proteobacteria in the cecal and colonic microbiota, as well as a decrease in the total bacterial numbers in both organs. Conclusions: It is evident that the intestinal microbiota plays a significant role in the host’s response to infection with enteric pathogens, and its composition and numbers are also affected by the offending bacteria. Elucidation of the details regarding the contribution of the microbiota to infectious disease progression will offer novel targets for the future design of superior prevention and treatment methods.

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