Effects of Pseudomonas cepacia and cultural factors on the nodulation of Alnus rubra roots by Frankia

1983 ◽  
Vol 61 (11) ◽  
pp. 2877-2882 ◽  
Author(s):  
Susan Knowlton ◽  
Jeffrey O. Dawson
Keyword(s):  
Calcium Concentration ◽  
Experimental System ◽  
Infection Process ◽  
Phosphate Concentration ◽  
Alnus Rubra ◽  
Pseudomonas Cepacia ◽  
Acidic Solutions ◽  
Cultural Conditions ◽  
Root Hair Deformation ◽  
Substrate Ph

Infection of Alnus rubra Bong, roots by Frankia isolates was consistently promoted by Pseudomonas cepacia "helper" bacteria under a variety of cultural conditions. Pseudomonas cepacia, while helpful, was never necessary in securing nodulation of aseptic A. rubra by Frankia. Live P. cepacia cells were added with a Frankia isolate to aseptically grown A. rubra seedlings on Hoagland's agar slants. This doubled, on average, the number of nodules formed by Frankia alone when Frankia isolate, age of Frankia inoculum, Frankia medium, calcium concentration of seedling substrate, phosphate concentration of seedling substrate, and pH of seedling substrate were varied. There was an apparent interaction between seedling substrate pH and P. cepacia in the promotion of nodulation. At pH levels from 4.0 to 6.0 the infectivity of Frankia isolate ArI3 alone was greatly depressed compared with infectivity at the optimal pH for the growth of ArI3, around 7.0. However, at pH levels of 5.0, 5.5, and 6.0 the ability of P. cepacia to promote nodulation of A. rubra seedlings by ArI3 was greater than at pH 7.0. This interaction may be due to the ability of P. cepacia to neutralize and grow more rapidly in mildly acidic solutions in our experimental system, combined with the ability of P. cepacia to cause root-hair deformation, which has been associated with the actinorhizal infection process.

Root hair deformation in the infection process of Alnus rubra

1983 ◽  
Vol 61 (11) ◽  
pp. 2863-2876 ◽  
Author(s):  
Alison M. Berry ◽  
John G. Torrey
Keyword(s):  
Root Hair ◽  
Cell Walls ◽  
Root Hairs ◽  
Infection Process ◽  
Alnus Rubra ◽  
Pseudomonas Cepacia ◽  
Developmental Studies ◽  
Experimental Conditions ◽  
Root Hair Cell ◽  
Root Hair Deformation

Structural and cell developmental studies of root hair deformation in Alnus rubra Bong. (Betulaceae) were carried out following inoculation with the soil pseudomonad Pseudomonas cepacia 85, alone or in concert with Frankia, and using axenically grown seedlings. Deformational changes can be observed in elongating root hairs within 2 h of inoculation with P. cepacia 85. These growing root hairs become branched or multilobed and highly modified from the single-tip growth of axenic root hairs. The cell walls of deformed hairs are histologically distinctive when stained with the fluorochrome acridine orange. Filtrate studies using P. cepacia 85 suggest that the deforming substance is not a low molecular weight compound. Root hair deformation and the associated wall histology are host specific in that Betula root hairs show none of these responses when grown and inoculated in the experimental conditions described. The bacterially induced changes in root hair cell walls during deformation may create a chemically and physically modified substrate for Frankia penetration, and the deformation itself may serve to entrap and enclose the filamentous organism, allowing wall dissolution and entry. Thus these events represent a complex host response as a precondition to successful nodulation.

scholarly journals Biofilm Accumulation and Sucrose Rinse Modulate the Calcium and Fluoride Bioavailability in the Saliva of Children with Early Childhood Caries

2022 ◽  
Author(s):  
Camila Lopes Crescente ◽  
Emerson Tavares de Sousa ◽  
Aline Tavares Lima-Holanda ◽  
Carolina Steiner-Oliveira ◽  
Marinês Nobre-dos-Santos
Keyword(s):  
Experimental Study ◽  
Early Childhood ◽  
Early Childhood Caries ◽  
Calcium Concentration ◽  
Phosphate Concentration ◽  
Combined Effect ◽  
Caries Experience ◽  
Mechanical Control ◽  
Quasi Experimental ◽  
Childhood Caries

Abstract This quasi-experimental study aimed at investigating the combined effect of biofilm accumulation and 20% sucrose rinse on the modulation of calcium (Ca2+), phosphate (Pi), and fluoride (F-) bioavailability in saliva of children with early childhood caries (ECC). In-that, fifty-six preschoolers of both genders were evaluated according to caries experience and activity: caries-free (CF, n=28) and with ECC (n=28) and then, submitted to biofilm intervention (biofilm accumulation or no biofilm accumulation). In each situation, saliva samples were collected before and five minutes after a 20% sucrose rinse to determine the concentrations of Ca2+, Pi, and F−. Calcium concentration was significantly lower in the biofilm accumulation situation compared to the situation of biofilm mechanical control, except for children CF after sucrose rinse. Biofilm accumulation increased salivary calcium concentration in children with ECC after sucrose rinse, whereas mechanical biofilm control reduced it in both groups. The phosphate concentration was influenced by mechanical control of the biofilm in CF children. The fluoride bioavailability was reduced by sucrose rinse and biofilm accumulation in CF and ECC children. In conclusion, the combined effect of biofilm accumulation and sucrose rinse modifies the bioavailability of calcium and fluoride in the saliva of children with early childhood caries.

Evidence that associated soil bacteria may influence root hair infection of actinorhizal plants by Frankia

1980 ◽  
Vol 26 (8) ◽  
pp. 971-977 ◽  
Author(s):  
Susan Knowlton ◽  
Alison Berry ◽  
John G. Torrey
Keyword(s):  
Root Hair ◽  
Low Frequency ◽  
Infection Process ◽  
Actinorhizal Plants ◽  
Bacterial Isolates ◽  
Bacterial Strains ◽  
Intimate Contact ◽  
Root Hair Deformation ◽  
Root Hair Infection ◽  
Axenic Conditions

Nodulation of actinorhizal plants (Alnus rubra Bong. and others) by isolated Frankia strains occurred either at a low frequency or not at all under axenic conditions. But nodulation was achieved under nonsterile conditions and four strains of bacteria were isolated which promoted nodulation when plants were inoculated with the bacteria plus Frankia. Four strains of Psendomonas cepacia also promoted nodulation. Root hair deformation occurred when roots of A. rubra were inoculated with these bacterial isolates, or with the bacteria plus Frankia, but rarely or not at all when roots were inoculated with the actinomycete alone. The nonendophytic bacterial strains were not detected within the nodule tissue. It is proposed that the bacterial isolates aid in the infection process at the host root hair surface, by causing root hair deformation; this may allow intimate contact between the Frankia filament and the hair wall.

Frankia spores of strain HFPCgI4 as inoculum for seedlings of Casuarina glauca

1991 ◽  
Vol 69 (6) ◽  
pp. 1251-1256 ◽  
Author(s):  
Samira R. Mansour ◽  
John G. Torrey
Keyword(s):  
Root Exudates ◽  
Spore Germination ◽  
Root Hair ◽  
Basal Medium ◽  
Infection Process ◽  
Casuarina Glauca ◽  
Seedling Root ◽  
Root Hair Deformation ◽  
Root Hair Infection

Spore suspensions of Frankia strain HFPCgI4 originally isolated from root nodules of Casuarina glauca were studied with respect to their capacity to germinate in vitro in chemically defined media and added root exudates. Spore germination in general was low and prolonged but could be increased by chemical additions to the basal medium and increased further (doubled percentages) by adding suitable dilutions of root exudates from C. glauca seedlings. Spores inoculated directly on seedling roots at 108 spores/mL caused seedling root hair deformation in C. glauca and some root nodulation (35%). Spore inoculation under axenic conditions elicited limited root hair deformation and no nodulation. Evidence is provided showing that Frankia spores of isolate HFPCgI4 serve as effective agents in root hair infection when applied in nonsterile water culture conditions. Seedling root exudates may facilitate the infection process by stimulating Frankia spore germination. Key words: Frankia, nodulation, root hair infection, root exudate, spores.

scholarly journals Impact of Fixed Orthodontic Therapy on Salivary Characteristics in Relation to Weight Status

2018 ◽  
Vol 11 (3) ◽  
pp. 1463-1470
Author(s):  
Zaid Ali Alasadi ◽  
Alhan Ahmed Qasim
Keyword(s):  
Flow Rate ◽  
Weight Status ◽  
Calcium Concentration ◽  
Normal Weight ◽  
Phosphate Concentration ◽  
Orthodontic Appliances ◽  
Chemical Characteristics ◽  
Orthodontic Therapy ◽  
Physical And Chemical Characteristics ◽  
Physical And Chemical

The aim of the present study is to evaluate the early impact of fixed orthodontic therapy on some salivary physical and chemical characteristics of patients in relation to their weight status. The sample consisted of 54 patients (25 males and 29 females; age between 16-18 years old) going under the course of fixed orthodontic treatment. Patients were categorized according to their Body Mass Index (BMI) into 3 weight status groups (underweight, normal weight, overweight and obese), then unstimulated salivary samples were collected from each patient who met specific inclusion and exclusion criteria during three time intervals; before bonding (1st visit), 2 weeks after bonding (2nd visit), and 4 weeks after bonding (3rd visit), then salivary samples are examined to evaluate some salivary physical properties (flow rate, pH) and some chemical properties (salivary calcium concentration, salivary phosphate concentration). A significant increase in salivary flow rate for all weight status categories during the 2ndvisit. A significant decrease in salivary pH for both underweight and overweight groups during 2nd visit with no significant change for normal weight group. A significant decrease in salivary calcium concentration for all weight status groups. And a significant increase in salivary phosphate concentration for all weight status groups. Exposure to fixed orthodontic appliances causes significant changes in salivary physical and chemical characteristics in early stages of treatment. These changes differ among patients with different BMI weight status, but with lesser intensity on normal weight patients than underweight and overweight and obese patients.

Effects of 1αOHD2 on bone tissue Studies of 1αOHD2 and 1αOHD3 in normal rats and in rats treated with prednisolone

1984 ◽  
Vol 106 (4) ◽  
pp. 564-568 ◽  
Author(s):  
G. O.J. Sjödén ◽  
O. Johnell ◽  
H. F. DeLuca ◽  
J. U. Lindgren
Keyword(s):  
Bone Density ◽  
Bone Mass ◽  
Calcium Concentration ◽  
Oral Treatment ◽  
Mean Value ◽  
Serum Phosphate ◽  
Phosphate Concentration ◽  
Male Rats ◽  
Serum Calcium Concentration ◽  
Vitamin D Analogue

Abstract. Three months old male rats were fed a diet containing 0.3% calcium and 0.5% phosphate. Prednisolone was added to the diet at a dose of 1.5 mg a day and the effect of oral treatment with 0.5 μg 1αOHD2 or 0.5 μg 1αOHD3 was studied. After 6 weeks rats given prednisolone had a lower bone mass and bone density. The serum phosphate concentration was also lower. Rats given 1αOHD3 had an increased serum calcium concentration even when simultaneously treated with prednisolone. 1αOHD2 did not cause hypercalcaemia. The decrease in bone density caused by prednisolone was prevented by the administration of 1αOHD2. Rats receiving 1αOHD3 together with prednisolone still exhibited a lower bone density. Furthermore, 1αOHD3 decreased bone mass in normal rats and caused a higher mean value of osteoclasts/area whereas 1αOHD2 reduced the number of osteoclasts/area. The study indicates that 1αOHD2 is an effective vitamin D analogue with a lower tendency to cause bone resorption.

Calcification of a Native Collagen Membrane

1977 ◽  
Vol 32 (11-12) ◽  
pp. 997-1002
Author(s):  
Günther Wiedner ◽  
Günther Wilhelm ◽  
G. Jureit ◽  
Z. Bojadžijev
Keyword(s):  
Calcium Phosphate ◽  
Calcium Concentration ◽  
Phosphate Concentration ◽  
Collagen Membrane ◽  
Ratio Dependence ◽  
Independent Variation ◽  
Native Collagen

Abstract Calcification, Collagen Membrane, Ca/P Ratio Dependence Spontaneous calcification of a membrane made of native collagen has been investigated. The method permits independent variation of calcium and phosphate concentrations. With increasing phosphate concentration the precipitation of calcium-phosphate on the collogen occurs at a conspicuously lower calcium concentration as with a number of other membranes.

Parathyroid Function in Uremic Children With and Without Osteodystrophy

PEDIATRICS ◽  
1974 ◽  
Vol 53 (3) ◽  
pp. 404-409
Author(s):  
Betty S. Roof ◽  
Carolyn F. Piel ◽  
Linda Rames ◽  
Donald Potter ◽  
Gilbert S. Gordan
Keyword(s):  
Serum Calcium ◽  
Calcium Concentration ◽  
Serum Magnesium ◽  
Tubular Reabsorption ◽  
Serum Phosphate ◽  
Phosphate Concentration ◽  
Normal Children ◽  
Serum Calcium Concentration ◽  
Parathyroid Function ◽  
Radiologic Evidence

Circulating radioimmunoassayable parathyroid hormone (iPTH) was not present in 30% (117) of 389 normal children tested at ages from cord blood to 17 years. In the other 70% (272), mean iPTH was found to be 25 ± 0.7µl eq/ml (± SEM; range, 0-53 ± 2 SD) . The iPTH levels were elevated in 59% of 24 uremic children without radiologic evidence of osteodystrophy in 94% uremic children with osteodystrophy. Infusion of calcium (10 mg/kg over three hours or 15 mg/kg over four hours) in the children without osteodystrophy reduced the iPTH by nearly 50%; suppression was sustained for 9 to 20 hours. In uremic children with osteodystrophy, similar infusions failed to elevate the serum calcium concentration to the same degree and there was less suppression of iPTH which was not sustained as long. Mean increment in serum calcium observed was 2.1 mg/100 ml with 10 mg/kg/3 hr and 3.4 for 15 mg/kg/4 hr in children without osteodystrophy, and 1.24 and 1.4 mg/100 ml in those with osteodystrophy for similar infusions. In both groups, calcium infusions lowered the concentration of serum magnesium and elevated the serum phosphate concentration. Tubular reabsorption of phosphate did not change consistently despite fall in serum iPTH levels. There was no correlation between suppressibility of parathyroid function and serum creatinine level. In five children with osteodystrophy in whom calcium infusions did not suppress iPTH levels, normal iPTH levels were achieved rapidly after successful renal transplantation. These data indicate that the secondary hyperparathyroidism of uremic children is suppressible and not autonomous.

Chemistry misconceptions associated with understanding calcium and phosphate homeostasis

2009 ◽  
Vol 33 (4) ◽  
pp. 323-328 ◽  
Author(s):  
William H. Cliff
Keyword(s):  
Calcium Phosphate ◽  
Chemical Equilibrium ◽  
Calcium Concentration ◽  
Phosphate Concentration ◽  
Phosphate Solution ◽  
Phosphate Homeostasis ◽  
Chemical Equilibria ◽  
Common Ion ◽  
The Common ◽  
Written Explanations

Successful learning of many aspects in physiology depends on a meaningful understanding of fundamental chemistry concepts. Two conceptual diagnostic questions measured student understanding of the chemical equilibrium underlying calcium and phosphate homeostasis. One question assessed the ability to predict the change in phosphate concentration when calcium ions were added to a saturated calcium phosphate solution. Fifty-two percent of the students correctly predicted that the phosphate concentration would decrease in accord with the common ion effect. Forty-two percent of the students predicted that the phosphate concentration would not change. Written explanations showed that most students failed to evoke the idea of competing chemical equilibria. A second question assessed the predicted change in calcium concentration after solid calcium phosphate was added to a saturated solution. Only 11% of the students correctly predicted no change in calcium concentration; 86% of the students predicted an increase, and many based their prediction on a mistaken application of Le Chatelier's principle to heterogeneous equilibria. These results indicate that many students possess misconceptions about chemical equilibrium that may hamper understanding of the processes of calcium and phosphate homeostasis. Instructors can help students gain greater understanding of these physiochemical phenomena by adopting strategies that enable students achieve more accurate conceptions of chemical equilibria.

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