scholarly journals Differential time-course tear film quantitative changes following limbal relaxing incisions

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Mohamed Attia Ali Ahmed ◽  
Ahmed Shawkat Abdelhalim
Keyword(s):  
Time Course ◽  
Tear Film ◽  
Quantitative Changes ◽  
Relaxing Incisions

scholarly journals A metabolomics characterisation of natural variation in the resistance of cassava to whitefly

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Laura Perez-Fons ◽  
Adriana Bohorquez-Chaux ◽  
Maria L. Irigoyen ◽  
Danielle C. Garceau ◽  
Kris Morreel ◽  
...  
Keyword(s):  
Time Course ◽  
Management Strategies ◽  
Resistance Mechanism ◽  
Central Africa ◽  
Susceptible Variety ◽  
Induced Response ◽  
Genotypic Differences ◽  
Germplasm Collections ◽  
Resistant Varieties ◽  
Quantitative Changes

Abstract Background Cassava whitefly outbreaks were initially reported in East and Central Africa cassava (Manihot esculenta Crantz) growing regions in the 1990’s and have now spread to other geographical locations, becoming a global pest severely affecting farmers and smallholder income. Whiteflies impact plant yield via feeding and vectoring cassava mosaic and brown streak viruses, making roots unsuitable for food or trading. Deployment of virus resistant varieties has had little impact on whitefly populations and therefore development of whitefly resistant varieties is also necessary as part of integrated pest management strategies. Suitable sources of whitefly resistance exist in germplasm collections that require further characterization to facilitate and assist breeding programs. Results In the present work, a hierarchical metabolomics approach has been employed to investigate the underlying biochemical mechanisms associated with whitefly resistance by comparing two naturally occurring accessions of cassava, one susceptible and one resistant to whitefly. Quantitative differences between genotypes detected at pre-infestation stages were consistently observed at each time point throughout the course of the whitefly infestation. This prevalent differential feature suggests that inherent genotypic differences override the response induced by the presence of whitefly and that they are directly linked with the phenotype observed. The most significant quantitative changes relating to whitefly susceptibility were linked to the phenylpropanoid super-pathway and its linked sub-pathways: monolignol, flavonoid and lignan biosynthesis. These findings suggest that the lignification process in the susceptible variety is less active, as the susceptible accession deposits less lignin and accumulates monolignol intermediates and derivatives thereof, differences that are maintained during the time-course of the infestation. Conclusions Resistance mechanism associated to the cassava whitefly-resistant accession ECU72 is an antixenosis strategy based on reinforcement of cell walls. Both resistant and susceptible accessions respond differently to whitefly attack at biochemical level, but the inherent metabolic differences are directly linked to the resistance phenotype rather than an induced response in the plant.

scholarly journals Changes in intermediate haemoglobins during autoxidation of haemoglobin

1981 ◽  
Vol 195 (2) ◽  
pp. 485-492 ◽  
Author(s):  
A Tomoda ◽  
Y Yoneyama ◽  
A Tsuji
Keyword(s):  
Isoelectric Focusing ◽  
Phosphate Buffer ◽  
Time Course ◽  
Inositol Hexaphosphate ◽  
Reaction Rate Constants ◽  
The Media ◽  
Beta 2 ◽  
Quantitative Changes ◽  
Ph Range ◽  
Experimental Values

The time course of haemoglobin autoxidation was studied under various conditions at 37 degrees C, and the changes in oxyhaemoglobin, intermediate haemoglobins and methaemoglobin during the reaction were analysed by isoelectric focusing on Ampholine/polyacrylamide-gel plates. Under various conditions (10 mM-phosphate buffer, 10 mM-phosphate buffer with 0.1 M-phosphate buffer, 10 mM-phosphate buffer with 0.1 M-NaCl, and 10 mM-phosphate buffer with 0.5 mM-inositol hexaphosphate; pH range 6.6-7.8 each case), the intermediate haemoglobins were found to be present as (alpha 2+ beta 3+)2 and (alpha 3+ beta 2+)2 valency hybrids from their characteristic positions on electrophoresis. Oxyhaemoglobin changed consecutively to (alpha 2+ beta 3+)2 and (alpha 3+ beta 2+)2, which were further oxidized to methaemoglobin, and the amounts of (alpha 3+beta 2+)2 were greater than those of (alpha 2+ beta 3+)2 during the reaction. The modes of the quantitative changes in oxyhaemoglobin, intermediate haemoglobins, and methaemoglobin were very similar in all the media used except for the inositol hexaphosphate addition. In the presence of inositol hexaphosphate, the autoxidation rates were considerably accelerated, and the modes of the changes in the haemoglobin derivatives were also considerably altered; the effects of this organic phosphate were maximal at acidic pH and minimal at alkaline pH. It was concluded that haemoglobin autoxidation proceeds by first-order kinetics through two paths: and (formula: see text). The reaction rate constants (k+1-k+4) best fitting all experimental values obtained by the isoelectric-focusing analysis were evaluated. By using these values, the mechanism of haemoglobin autoxidation is discussed.

Insulin secretion by rat lachrymal glands: effects of systemic and local variables

2005 ◽  
Vol 289 (5) ◽  
pp. E768-E775 ◽  
Author(s):  
Daniel Andrade Cunha ◽  
Everardo M. Carneiro ◽  
Mônica de C. Alves ◽  
Angélica Gobbi Jorge ◽  
Sylvia Morais de Sousa ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Time Course ◽  
Physiological Role ◽  
Tear Film ◽  
Insulin Level ◽  
Glucose Consumption ◽  
In Vitro Assays ◽  
Corneal Tissue ◽  
Metabolic Role

To understand the secretory mechanisms and physiological role of insulin in the tear film, the present study examined 1) the time course of insulin secretion in the tear film under glucose intravenous stimulation, 2) the glucose- and carbachol-induced insulin secretion from isolated lachrymal gland (LG), 3) the effect of insulin on glucose consumption by the cornea, and 4) the expression of insulin, pancreatic duodenal homeobox-1 (PDX-1), and glucose transport proteins (GLUTs) in LG tissue. The insulin level in the tear film of 8-wk-old male Wistar rats increased from 0.6 ± 0.45 to 3.7 ± 1.3 ng/ml in the initial minutes after glucose stimulation. In vitro assays demonstrated that higher glucose concentrations from 2.8 to 16.7 mM, 200 μM carbachol, or 40 mM KCl significantly increased insulin secretion from lacrimal glands compared with controls, but did not detect C-peptide as measured by RIA. Glucose consumption by corneal tissue, evaluated by radiolabeled d-[U-14C]glucose uptake, was 24.07 ± 0.61 and was enhanced to 31.63 ± 3.15 nmol·cornea−1·2 h−1 in the presence of 6 nM insulin ( P = 0.033) and to 37.5 ± 3.7 nmol·cornea−1·2 h−1 in the presence of 11.2 mM glucose ( P = 0.015). Insulin and PDX-1 mRNA was detected in LG. Insulin was located in the apical areas of acinar cells by immunoperoxidase and the expression of GLUT-1, but not PDX-1, was confirmed by Western blot. These findings suggest that insulin secretion in the tear film is influenced by local stimuli such as nutrient and neural inputs and that this hormone plays a metabolic role in ocular surface tissues. These data also indicate that under normal conditions the insulin secreted by LG is stored, but it is not clear that is locally produced in the LG.

PIXE STUDIES ON POTASSIUM AND CALCIUM IN MOUSE BLOOD PLASMA AFTER TRANSPLANTATION OF EL-4 TUMOR CELLS

1995 ◽  
Vol 05 (04) ◽  
pp. 255-264 ◽  
Author(s):  
ITSURO TAMANOI ◽  
AKEMI NAKAMURA ◽  
KIYOFUSA HOSHIKAWA ◽  
MUTSUMI KACHI ◽  
KUNIO OOHASHI ◽  
...  
Keyword(s):  
Blood Plasma ◽  
Tumor Cells ◽  
Time Course ◽  
The Other ◽  
Histocompatibility Antigens ◽  
Mouse Blood ◽  
Major Histocompatibility Antigens ◽  
The Difference ◽  
Quantitative Changes ◽  
Pixe Method

The quantitative changes in the elements, amounts of Cl, K, Ca, in blood plasma were measured by PIXE method. The samples were obtained at appropriate intervals after transplantation of EL-4 tumor cells in three strains of mice, C57BL/6J (H-2b), C57BL/10J (abbreviation: B10; H-2b) and A/J (H-2a). Transplanted EL-4 tumor cells proliferated in both strains of C57BL/6J and B10. In A/J mice, transplanted EL-4 cells proliferated about 10 days and then were rejected completely by the immunological reaction according to the difference of major histocompatibility antigens. The amounts of Cl in plasma remained at similar level in the time course in any strains, but K fluctuated in C57BL/6J and B10, and less in A/J. On the other hand, Ca showed always higher values in C57BL/6J than other two strains of mice. In B10 mice, Ca increased just before death, but in A/J it decreased at the time of healing by rejection. These changes of Ca in the three strains of mice were related quantitatively 10 the hematocrit values of these strains of mice after transplantation of EL-4 cells.

Effect of carbon monoxide exposures on erythrocytic 2,3-DPG in rabbits

1976 ◽  
Vol 41 (5) ◽  
pp. 689-692 ◽  
Author(s):  
J. M. Ramsey ◽  
P. W. Casper
Keyword(s):  
Carbon Monoxide ◽  
Time Course ◽  
Exposure Period ◽  
Sampling Time ◽  
Quantitative Changes ◽  
2,3 Dpg

To determine if an exposure to lower levels of carbon monoxide (CO) produces quantitative changes in erythrocytic 2,3-diphosphoglycerate (2,3-DPG), eight rabbits were exposed to 100 ppm CO for 5 h resulting in approximately 20% carboxyhemoglobin (HbCO). 2,3-DPG was determined before exposure and immediately after exposure as well as every 3 h during the 24 h following exposure. To determine if intermittent CO exposures over a prolonged period of time affect 2,3-DPG, an additional 12 rabbits were exposed to 250 ppm CO for three intermittent periods totaling 300 min daily for 14 days (30% HbCO). 2,3-DPG was determined once per animal at the end of each day's exposure period. All animals served as their own controls in both experiments. Neither the results of the 24-h time course nor those of the 14-day time course showed significant differences in mean 2,3-DPG between controls and exposed animals at any sampling time. Apparently erythrocytic 2,3-DPG plays neither a compensating nor aggravating role in respect to the hypoxia induced by these levels of HbCO in the rabbit.

scholarly journals Insect Elicitors and Exposure to Green Leafy Volatiles Differentially Upregulate Major Octadecanoids and Transcripts of 12-Oxo Phytodienoic Acid Reductases in Zea mays

2007 ◽  
Vol 20 (6) ◽  
pp. 707-716 ◽  
Author(s):  
Jürgen Engelberth ◽  
Irmgard Seidl-Adams ◽  
Jack C. Schultz ◽  
James H. Tumlinson
Keyword(s):  
Zea Mays ◽  
Time Course ◽  
Mechanical Damage ◽  
Insect Herbivore ◽  
Plant Insect Interactions ◽  
Volatile Organic ◽  
Herbivore Attack ◽  
Quantitative Changes ◽  
Insect Interactions ◽  
Defensive Measures

The induction of jasmonic acid (JA) is one of the major signaling events in plants in response to insect herbivore damage and leads to the activation of direct and indirect defensive measures. Green leafy volatiles, which constitute a major portion of volatile organic compounds, often are released in response to insect herbivore attack and have been shown to significantly activate JA production in exposed corn (Zea mays) seedlings, thereby priming these plants specifically against subsequent herbivore attack. To explore the factors determining the specificity of the octadecanoid signaling pathway in corn, we analyzed qualitative and quantitative changes in major octadecanoids. The time course and the amount of induced JA and 12-oxophytodienoic acid levels in corn seedlings were strikingly different after wounding, application of caterpillar regurgitant, or treatment with cis-3-hexenyl acetate (Z-3-6:AC). Exposure to Z-3-6:AC induced accumulation of transcripts encoded by three putative 12-oxophytodienoate10,11-re-ductase genes (ZmOPR1/2, ZmOPR5, and ZmOPR8). Although changes in ZmOPR5 RNAs were detected only after exposure to Z-3-6:AC, ZmOPR1/2 RNAs and ZmOPR8 RNAs also were abundant after treatment with crude regurgitant elicitor or mechanical damage. The physiological implications of these findings in the context of plant-insect interactions are discussed.

Ultrastructural Changes of the Symbiotic Chlorella-Like Alga Isolated from Hydra Viridis

1982 ◽  
Vol 40 ◽  
pp. 320-321
Author(s):  
K.W. Lee ◽  
R.H. Meints ◽  
D. Kuczmarski ◽  
J.L. Van Etten
Keyword(s):  
Time Course ◽  
Reciprocal Cross ◽  
Ultrastructural Level ◽  
Ultrastructural Changes ◽  
Symbiotic Relationship ◽  
Cell Recognition ◽  
Green Hydra ◽  
Different Strains ◽  
Hydra Viridis

The physiological, biochemical, and ultrastructural aspects of the symbiotic relationship between the Chlorella-like algae and the hydra have been intensively investigated. Reciprocal cross-transfer of the Chlorellalike algae between different strains of green hydra provide a system for the study of cell recognition. However, our attempts to culture the algae free of the host hydra of the Florida strain, Hydra viridis, have been consistently unsuccessful. We were, therefore, prompted to examine the isolated algae at the ultrastructural level on a time course.

Destruction of Actin Filaments by Osmium Tetroxide

1977 ◽  
Vol 35 ◽  
pp. 466-467
Author(s):  
P. Maupin-Szamier ◽  
T. D. Pollard
Keyword(s):  
Actin Filaments ◽  
Time Course ◽  
Osmium Tetroxide ◽  
Rabbit Muscle ◽  
Muscle Actin ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
The Difference ◽  
Rates Of Decay ◽  
Short Time

We have studied the destruction of rabbit muscle actin filaments by osmium tetroxide (OSO4) to develop methods which will preserve the structure of actin filaments during preparation for transmission electron microscopy.Negatively stained F-actin, which appears as smooth, gently curved filaments in control samples (Fig. 1a), acquire an angular, distorted profile and break into progressively shorter pieces after exposure to OSO4 (Fig. 1b,c). We followed the time course of the reaction with viscometry since it is a simple, quantitative method to assess filament integrity. The difference in rates of decay in viscosity of polymerized actin solutions after the addition of four concentrations of OSO4 is illustrated in Fig. 2. Viscometry indicated that the rate of actin filament destruction is also dependent upon temperature, buffer type, buffer concentration, and pH, and requires the continued presence of OSO4. The conditions most favorable to filament preservation are fixation in a low concentration of OSO4 for a short time at 0°C in 100mM sodium phosphate buffer, pH 6.0.

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