Oxygen uptake by motile and germinating zoospores of Pythium aphanidermatum

1974 ◽  
Vol 52 (3) ◽  
pp. 669-671
Author(s):  
Yung Chang-Ho
Keyword(s):  
Oxygen Uptake ◽  
Respiratory Rate ◽  
Root Exudate ◽  
Pythium Aphanidermatum ◽  
Appreciable Effect ◽  
Pea Root ◽  
Measured Addition

Oxygen uptake by Pythium aphanidermatum zoospores during motility, encystment, and germination was measured. Addition of glucose or fructose had no appreciable effect on motile zoospore respiration. The effects of various substrates on the respiratory rate of germinating cysts were as follows: glucose, glucose-6-phosphate, xylose, acetate, citrate, glutamate, and 6-phosphogluconate did not increase the respiratory rate; whereas fructose, fructose-6-phosphate, iructose-l,6-diphosphate, sucrose, alphaketoglutarate, pyruvate, and dilute pea root exudate all significantly increased cyst respiration.

The effect of pea root exudate on the germination of Pythium aphanidermatum zoospore cysts

1970 ◽  
Vol 48 (9) ◽  
pp. 1501-1514 ◽  
Author(s):  
Yung Chang-Ho
Keyword(s):  
Organic Acids ◽  
Germ Tube ◽  
Root Exudate ◽  
Pythium Aphanidermatum ◽  
Tube Growth ◽  
Percentage Germination ◽  
Pea Root ◽  
Low Concentrations ◽  
Germination And Growth ◽  
Germ Tube Growth

Zoospore cysts of Pythium aphanidermatum germinated well without external nutrient supply, but pea root exudate increased percentage germination and germ tube growth. Zoospore cyst germination and growth varied with different concentrations of the substrate supplied. Alone, the neutral fraction (sugars) increased percentage germination but had little effect on germ tube growth; the cationic fraction (amino acids) suppressed germination and growth somewhat, except at very low concentrations; the anionic fraction (organic acids) mildly stimulated both processes. Neutral and anionic fractions combined approached the stimulatory effect of root exudate. Amongst the components of root exudate tested as pure chemicals, fructose, histidine, homoserine, proline, and tartaric acid promoted germination and growth at low concentrations. Alpha-alanine, glutamine, serine, and valine became stimulatory at high concentrations. A combination of glucose with one of the organic acids was more effective than either alone.

COMPARISON BETWEEN SEASONAL AND THERMAL ACCLIMATION IN WHITE RATS: II. SURFACE TEMPERATURE, VASCULARIZATION, AND IN VITRO RESPIRATION OF THE SKIN

1959 ◽  
Vol 37 (1) ◽  
pp. 1247-1253 ◽  
Author(s):  
O. Héroux
Keyword(s):  
Oxygen Uptake ◽  
Surface Temperature ◽  
Respiratory Rate ◽  
Environmental Conditions ◽  
Cold Temperature ◽  
Dorsal Skin ◽  
Adult Rats ◽  
White Rats ◽  
Different Types

The effect of cold temperature on the skin was studied on white rats exposed to two different types of environmental conditions. Two groups of adult rats kept in individual cages were continuously exposed for 3 months to constant cold temperature (18° and 6 °C) in the laboratory (indoor rats) while other groups of the same colony kept in groups of 10 were exposed for the same length of time to the fluctuating environmental conditions prevailing outside (outdoor rats).Indoor rats acclimated to 18 °C and 6 °C showed the same increase in the number of opened capillaries in the ears over the number observed in controls acclimated to 30 °C. "Summer and winter" outdoor rats showed the same number of capillaries as the "18 °C or 6 °C" indoor rats. Signs of injury healing such as thicker epidermis and larger nuclei were found in the ears of all the "6 °C" rats but in none of the "winter" rats. While the skin temperature measured at + 6 °C was slightly higher (0.4 to 1.0 °C) in rats acclimated at 6 °C than in those at 30 °C, it was lower (1.3 to 2.9 °C) in "winter" than in "summer" rats. After 28 days of acclimation, the rate of oxygen uptake of the dorsal skin of the foot was lower in "6 °C" than in "30 °C" rats but after 84 days it was significantly higher in the cold-acclimated rats. Similarly, after 3 months, the respiratory rate of the dorsal skin of the foot was higher in "winter" rats than in "summer" rats.

ANALYSIS OF FACTORS GOVERNING IN VITRO ACCUMULATION OF ZOOSPORES OF PYTHIUM APHANIDERMATUM ON ROOTS: I. BEHAVIOR OF ZOOSPORES

1964 ◽  
Vol 10 (2) ◽  
pp. 151-162 ◽  
Author(s):  
D. J. Royle ◽  
C. J. Hickman
Keyword(s):  
Root Exudate ◽  
Pythium Aphanidermatum ◽  
Root Tips ◽  
Water Suspension ◽  
Large Numbers ◽  
Wide Range ◽  
Early Germination ◽  
Pea Roots ◽  
Germ Tubes

Zoospores of Pythium aphanidermatum in distilled water suspension responded to intact pea roots by massing in large numbers at the sites of elongation behind the root tips. They showed preferential attraction to wounds made by puncturing the epidermis, and to the stele exposed at the cut ends of roots. Massing of zoospores was followed, almost immediately, by encystment and early germination, the germ tubes being directed towards the source of stimulation. The phenomenon was non-specific over a wide range of plants examined. Root exudate and extract, diffusing from the ends of capillary tubes containing these materials in agar, caused identical zoospore responses. Analysis of zoospore movement under stimulation revealed a sequence of responses—initial disruption of the typical course of movement, attraction, trapping, and early cessation of movement by encystment. Attraction was equated with chemotaxis, whilst trapping showed features of kineses.

COMPARISON BETWEEN SEASONAL AND THERMAL ACCLIMATION IN WHITE RATS: II. SURFACE TEMPERATURE, VASCULARIZATION, AND IN VITRO RESPIRATION OF THE SKIN

1959 ◽  
Vol 37 (11) ◽  
pp. 1247-1253 ◽  
Author(s):  
O. Héroux
Keyword(s):  
Oxygen Uptake ◽  
Surface Temperature ◽  
Respiratory Rate ◽  
Environmental Conditions ◽  
Cold Temperature ◽  
Dorsal Skin ◽  
Adult Rats ◽  
White Rats ◽  
Different Types

The effect of cold temperature on the skin was studied on white rats exposed to two different types of environmental conditions. Two groups of adult rats kept in individual cages were continuously exposed for 3 months to constant cold temperature (18° and 6 °C) in the laboratory (indoor rats) while other groups of the same colony kept in groups of 10 were exposed for the same length of time to the fluctuating environmental conditions prevailing outside (outdoor rats).Indoor rats acclimated to 18 °C and 6 °C showed the same increase in the number of opened capillaries in the ears over the number observed in controls acclimated to 30 °C. "Summer and winter" outdoor rats showed the same number of capillaries as the "18 °C or 6 °C" indoor rats. Signs of injury healing such as thicker epidermis and larger nuclei were found in the ears of all the "6 °C" rats but in none of the "winter" rats. While the skin temperature measured at + 6 °C was slightly higher (0.4 to 1.0 °C) in rats acclimated at 6 °C than in those at 30 °C, it was lower (1.3 to 2.9 °C) in "winter" than in "summer" rats. After 28 days of acclimation, the rate of oxygen uptake of the dorsal skin of the foot was lower in "6 °C" than in "30 °C" rats but after 84 days it was significantly higher in the cold-acclimated rats. Similarly, after 3 months, the respiratory rate of the dorsal skin of the foot was higher in "winter" rats than in "summer" rats.

scholarly journals Effect of atractyloside on glucose and pyruvate metabolism in rat diaphragm muscle

1968 ◽  
Vol 107 (2) ◽  
pp. 305-309 ◽  
Author(s):  
F. Pocchiari ◽  
V. Silano
Keyword(s):  
Oxygen Uptake ◽  
Glycogen Synthesis ◽  
Specific Radioactivity ◽  
Carbon Dioxide Production ◽  
Diaphragm Muscle ◽  
Appreciable Effect ◽  
Rat Diaphragm ◽  
Substrate Level ◽  
Lactate Formation ◽  
Anaerobic Production

1. In the presence of 1·2mm-atractyloside oxygen uptake by rat diaphragm muscle incubated with 5·6mm-glucose decreases, as well as glycogen synthesis and carbon dioxide production. Lactate formation from glucose increases, but that of phosphoglycerate diminishes fivefold. 2. When pyruvate is used as substrate, atractyloside decreases oxygen uptake. 3. The specific radioactivity of the 14CO2 (μmoles of 14CO2/μmole of oxygen), calculated at concentrations of [1−14C]pyruvate between 0·091mm and 91mm, lies between 3·1×10−4 and 5·7×10−1. Atractyloside increases the specific radioactivity of the 14CO2 with the lowest concentrations of substrate and has no effect when the substrate concentration is 91mm. 4. No appreciable effect of atractyloside on the anaerobic production of 14CO2 from [1−14C]pyruvate at various incubation times and various concentrations is found. 5. It is suggested that atractyloside induces anaerobic conditions in the tissue. Further, it produces a rise in the pyruvate concentration and an ATP deficiency in the cell. Consequently it stimulates pyruvate dismutation, and glycolysis, to which phosphorylation is linked at the substrate level.

ANALYSIS OF FACTORS GOVERNING IN VITRO ACCUMULATION OF ZOOSPORES OF PYTHIUM APHANIDERMATUM ON ROOTS: II. SUBSTANCES CAUSING RESPONSE

1964 ◽  
Vol 10 (2) ◽  
pp. 201-219 ◽  
Author(s):  
D. J. Royle ◽  
C. J. Hickman
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Root Exudate ◽  
Pythium Aphanidermatum ◽  
Active Principle ◽  
Weak Base ◽  
Carbon And Nitrogen ◽  
Wide Range ◽  
Related Compounds

Pythium aphanidermatum zoospores in distilled water suspension showed differential responses towards a range of single compounds, and mixtures, diffusing from the ends of capillary tubes containing these materials in agar. All substances caused an initial disorientation of zoospore movement followed, according to the substance under test, by indifference, repulsion, attraction, trapping, and encystment, or, at extreme pH, by loss of motility and death. Of a wide range of substances and mixtures tested, including sugars, amino acids, inorganic salts, organic acids, auxins, and vitamins, only glutamic acid, after weak base adjustment, and mixtures of sugars combined with mixtures of amino acids, induced the pattern of response observed with roots and root materials. Comparison of the activity of glutamate and structurally related compounds indicated that the effectiveness of glutamate was dependent on the presence of several moieties of the glutamate ion.Short photographic exposures allowed counts to be made of zoospores and cysts around the capillary mouth and provided a method for comparing, quantitatively, the accumulation of zoospores in response to different substances over a period of time.The substances inducing activity were readily detected in pea root exudate and extract and are, in fact, of general occurrence in roots. The effectiveness of the active principle(s) in root exudate and extract was roughly proportional to the concentration of these root materials in terms of their content of carbon and nitrogen but no such relation could be established for glutamic acid and a joint mixture of amino acids and sugars, suggesting the existence in root materials of additional factor(s).

scholarly journals Effects of low intensity interval training on physiological variables of university students

2021 ◽  
Vol 25 (5) ◽  
pp. 333-341
Author(s):  
Assegid K. Ketema
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Uptake ◽  
Respiratory Rate ◽  
Interval Training ◽  
Control Group ◽  
P Value ◽  
Physiological Variables ◽  
Low Intensity ◽  
And Control

Background and Study Aim. This study was to investigate the effects of low-intensity interval training on the physiological variables of university students. Material and Methods. Forty male sports science students aged 18-25 years were randomly assigned to the Experimental group (n=20) and the Control group (n=20). The Experimental group underwent low-intensity interval training for eight weeks, whereas the Control group did not. Measurements of physiological variables such as resting heart rate, respiratory rate, recovery heart rate, breath-hold time, maximal oxygen uptake, and blood pressure were obtained for all subjects before and after the intervention. To compare the mean physiological variables between the experimental and control groups, an independent samples t-test was used. Results. Statistical significance was set at p 0.05. After the training intervention, the experimental group showed significantly better improvements than the control group in resting heart rate, respiratory rate, recovery heart rate, breath-holding time, maximal oxygen uptake, and blood pressure (p 0.05). Post intervention maximum oxygen uptake was statistically significant with t (38) = 3.086, p value 0.004. Post experiment systolic blood pressure was statistically significant with t (38) = -2.405, p value 0.021 for low intensity interval training and control group. Post experiment diastolic blood pressure was statistically highly significant with t (38) = 0.569, p value 0.001 for low intensity interval training and control group. The result of the study showed that there was a significant difference in post rest heart rate, respiratory rate, recovery heart rate, systolic blood pressure, diastolic blood pressure, breath holding and maximal oxygen uptake between the low intensity interval training and the control group (p 0.05). Conclusions. Thus, it was concluded that eight weeks of low-intensity interval training show significant improvement in physiological variables of university students.

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