POLYSACCHARIDES EXTRACELLULAIRES DE RHIZOBIUM MELILOTI

1967 ◽  
Vol 13 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Noëlle Amarger ◽  
M. Obaton ◽  
H. Blachère

The composition of the extracellular polysaccharides of 10 strains of Rhizobium meliloti was investigated. Glucose, galactose, and glucuronic acid were found as components; their amounts, determined after hydrolysis as a percentage of the total sugars, varied from 82 to 86 for glucose, 13 to 16 for galactose, and 0.4 to 1.2 for glucuronic acid. No significant difference between the strains was found, which suggests a homogeneity of the extracellular polysaccharides of Rhizobium meliloti.

Author(s):  
Abdul R. Rahman

An economical method was developed for producing a flour of acceptable quality from green plantains. Five lots weighing 20 pounds each were prepared for dehydration as follows: Peeled by hand and sliced, unpeeled and sliced, unpeeled sliced and treated with 2-percent potassium metabisulfite, and unpeeled sliced and treated with 2-percent citric acid. The results follow: 1. The yield of the flour produced from the plantains which were unpeeled and treated with potassium metabisulfite, 31 to 32 percent, was higher than that produced from the peeled ones, which was 25 to 28 percent. It also showed a trend towards increase in yield compared with the rest of the flours. 2. This flour also possessed better color than the one produced from the unpeeled and untreated plantains, or the flour from plantains treated with citric acid. 3. The flours produced from the treated plantains showed a relatively higher moisture and a trend towards lower total sugars and proteins than the untreated ones. 4. The calories per gram produced from all the flours were almost the same, whereas the bulk density was higher in the flour produced from the steam-peeled plantains than in the rest of the flours which were all about the same. 5. The organoleptic tests established no significant difference between the flavor of soups and "buñuelos" (crullers) prepared from the following flours: Unpeeled not treated, unpeeled but treated with potassium metabisulfite, unpeeled and treated with citric acid, and hand-peeled. However, a significant difference was established in favor of the color of the flour prepared from the unpeeled plantains treated with potassium metabisulfite as compared with flours made from untreated, unpeeled plantains, and from those treated with citric acid.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
François Ezin Azonwade ◽  
Armand Paraïso ◽  
Cokou P. Agbangnan Dossa ◽  
Victorien T. Dougnon ◽  
Christine N’tcha ◽  
...  

Honey is a very complex biological product. It has great diversity, giving it a multitude of properties, both nutritionally and therapeutically. This study aimed to study the physicochemical and microbiological characteristics of honeys collected during the dry and rainy seasons in the different phytogeographical areas of Benin. The study revealed that all honeys had pH, water content, electrical conductivity, ash content, free acidity, total sugars, and reducing sugars, respectively, ranging within 3.65–4.09; 12.07–13.16%; 530.25–698.50 μs/cm; 0.42–0.53%; 35.67–40.52 meq/kg; 60–70%; and 58–70%. Moisture content, total sugars, and reducing sugars varied very significantly (p<0.05top<0.001) from one area to another and from one season to another. However, only the production season has a significant influence (p<0.05) on the pH of the honey. With regard to the ash content, free acidity, and electrical conduction, no significant difference (p>0.05) between the zones or between the seasons was observed. The results of the microbiological characterization showed that there is heterogeneity in the microbial load. These results have shown that these honeys meet international standards and their characterization will make it possible to obtain Beninese quality labels.


1974 ◽  
Vol 46 (4) ◽  
pp. 511-518
Author(s):  
M. L'E. Orme ◽  
L. Davies ◽  
A. Breckenridge

1. Antipyrine in a dose of 3·2 mmol (600 mg) daily for 6 weeks produced a significant fall in both total and unconjugated serum bilirubin concentrations in six patients with Gilbert's syndrome. The maximum reduction in serum bilirubin concentration was seen after 2 weeks of treatment. 2. In the rat, administration of antipyrine in doses of 0·42 and 1·27 mmol 24 h−1 kg−1 (80 and 240 mg 24 h−1 kg−1) for 84 h caused a significant increase in the apparent maximal velocity (Vmax.) for the glucuronidation of bilirubin by liver microsomal preparations when the concentration of either uridine diphosphate glucuronic acid (UDPGA) or bilirubin was altered. There was no significant difference between the apparent Vmax. values attained with the two doses of antipyrine in either set of experiments. Neither the microsomal protein content nor the apparent affinity constant (Km) was altered in these studies. 3. In contrast, administration of phenobarbitone in doses of 0·34 mmol 24 h−1 kg−1 (80 mg 24 h−1 kg−1) caused a significant increase in the microsomal protein content but there was no significant change in the values for the apparent Vmax. or apparent Km for the glucuronidation of bilirubin with various concentrations of both UDPGA and bilirubin.


1960 ◽  
Vol 38 (9) ◽  
pp. 1617-1624 ◽  
Author(s):  
M. J. Abercrombie ◽  
J. K. N. Jones ◽  
M. V. Lock ◽  
M. B. Perry ◽  
R. J. Stoodley

The extracellular polysaccharides produced by Cryptococcuslaurentii have been isolated and shown to consist of (A) an acidic polysaccharide containing D-mannose, D-xylose, and D-glucuronic acid; (B) a neutral polysaccharide containing D-glucose only.Preliminary structural studies on the acidic material suggest that it consists of a mannose-containing backbone with xylose and glucuronic acid as end groups, while the glucan contains 1 → 3, 1 → 4, 1 → 2, and (or) 1 → 6 linked residues.


1998 ◽  
Vol 64 (3) ◽  
pp. 1024-1028 ◽  
Author(s):  
Javier Lloret ◽  
Brande B. H. Wulff ◽  
Jose M. Rubio ◽  
J. Allan Downie ◽  
Ildefonso Bonilla ◽  
...  

ABSTRACT The halotolerant strain Rhizobium meliloti EFB1 modifies the production of extracellular polysaccharides in response to salt. EFB1 colonies grown in the presence of 0.3 M NaCl show a decrease in mucoidy, and in salt-supplemented liquid medium this organism produces 40% less exopolysaccharides. We isolated transposon-induced mutant that, when grown in the absence of salt, had a colony morphology (nonmucoid) similar to the colony morphology of the wild type grown in the presence of salt. Calcofluor fluorescence, proton nuclear magnetic resonance spectroscopy, and genetic analysis of the mutant indicated that galactoglucan, which is not produced under normal conditions by other R. meliloti strains, is produced by strain EFB1 and that production of this compound decreases when the organism is grown in the presence of salt. The mutant was found to be affected in a genetic region highly homologous to genes for galactoglucan production in R. meliloti Rm2011 (expE genes). However, sequence divergence occurs in a putative expE promoter region. A transcriptional fusion of the promoter with lacZ demonstrated that, unlike R. meliloti Rm2011, galactoglucan is produced constitutively by EFB1 and that its expression is reduced 10-fold during exponential growth in the presence of salt.


2020 ◽  
Vol 16 ◽  
Author(s):  
Ke Su ◽  
Bingbao Chen ◽  
Xiaoting Tu ◽  
Luxin Ye ◽  
Xiaojie Lu ◽  
...  

Background: Xuezhikang capsule, which contains cholesterol synthase inhibitors and a large number of natural statins, is put in the clinical application of lipid-lowering and so on. However, the specific use of dose, lipid-lowering effect and the relationship between metabolites are to be further studied. Introduction: Metabonomics is the study of the relationship between the change of quantity and physiological changes from metabolites. At present metabolomics has been widely used in drug development and testing. In this study, we developed a metabolomic method based on gas chromatography-mass spectrometry (GC-MS) to find out hyperlipemia-related substances, and study the lipid-lowering mechanism of Xuezhikang. Method: Fifty SD rats (220 ± 20 g) were given high-fat diet. After four-weeks modeling, they were randomly divided into semi-control group, high fat group, simvastatin intervention group and Xuezhikang intervention group (0.23, 0.69, 1.15 mg/kg, low, medium, high), each dosage in eight rats. The control group (rest eight rats) were given normal diet, and no specific treatment. The rats were sacrificed at the end of the experiment. Result: The biochemical and body weight indexes of the normal control group and the high fat group were significantly different (P <0.05), which indicated that the model of hyperlipidemia was established success. There was significant difference (P <0.05) between Xuezhikang intervention group and high fat control group (P <0.05), and hyperlipemia metabolomics related markers, oxalic acid, butyric acid, mannitol, glucose, glucuronic acid were found. Glucuronic acid and non-binding bilirubin combined with bilirubin, combined with some of the liver harmful substances, play a detoxification effect. Conclusion: The results of metabonomics showed that the high fat group and the control group were significant difference. Mannose, glucose content is relatively stable, lipid metabolism in high-fat group stearic acid, palmitic acid levels decreased, suggesting that high-fat diet disorders rat body lipid metabolism. It is worth mentioning that the experimental evaluation of rats such as biochemical indicators and pathological results are prompted to model success, Xuezhikang intervention effect is more significant, consistent with the expected.


1964 ◽  
Vol 42 (10) ◽  
pp. 1403-1413 ◽  
Author(s):  
G. A. Adams ◽  
S. M. Martin

Growth of Serratia marcescens on sucrose, D-glucose, D-galactose, and D-xylose as carbon sources did not affect the composition of the extracellular polysaccharides significantly. D-Glucose was the major component with lesser amounts of D-mannose, heptose, L-fucose, and L-rhamnose. Rhamnose did not appear until near the end of the active growth period and increased proportionately more than the other sugars thereafter. From the culture filtrate after 20 hours growth on sucrose, two acidic polysaccharides were isolated. They were markedly different in composition and electrophoretic behavior although both contained glucose as their major component. One was characterized by a relatively high content of rhamnose and heptose, the other by the presence of mannose; both contained glucuronic acid. Other impure polysaccharides were isolated from the culture filtrate. It seems likely that S. marcescens produced a spectrum of rather similar extracellular polysaccharides of which the two isolated ones comprise the main types.


1963 ◽  
Vol 41 (9) ◽  
pp. 2357-2361 ◽  
Author(s):  
P. A. J. Gorin ◽  
J. F. T. Spencer

The extracellular polysaccharide formed from Xanthomonas hyacinthi is shown to be a branched polymer containing glucuronic acid, mannose, and glucose. Acid and enzymic hydrolysis show the presence of β-D-Glp 1 → 4 D-Man and the 4-unit sequence β-D-GlpA1 → 2 D-Manp 1 → 3 β-D-Glp 1 → 4 D-Gl. Examination by the methylation technique showed the presence of a considerable proportion of 2-linked mannopyranose units. The spectrum of methyl glycosides formed from this polysaccharide and those from Xanthomonas maculofoliigardeniae and Xanthomonas translucens are similar, and in terms of sugar linkages differentiate them from that of Xanthomonas stewartii, which contains glucuronic acid, glucose, and galactose.


1969 ◽  
Vol 37 (3) ◽  
pp. 199-205
Author(s):  
Rafael Santini, Jr.

(1) Ascorbic acid is the substance responsible for the discrepancies found in the determination of reducing sugars and total sugars by the Lane-Eynon method. By correcting for ascorbic acid using the factor (F) 0.686, the discrepancy is eliminated and the Lane-Eynon method can be used. (2) To determine the total sugar content of West Indian cherry juice corrected reducing sugars only need be assayed, because it was proved experimentally and statistically that there is no significant difference between corrected reducing and corrected total sugars. (3) The sugar content of West Indian cherry juices stored at room temperature and at 45°F. does not change appreciably after 1 year. (4) At 45°F. ascorbic acid is lost less readily than at room temperature, but temperature produces no significant difference in the true sugar content of the juice.


Author(s):  
Noemi Díaz

The chironja is a citrus fruit with some morphological characteristics of the orange (Citrus sinensis) and some of the grapefruit (Citrus paradisi). Because of the lack of information on the response of chironja to storage conditions, a study was conducted to evaluate its keeping quality. Five clones grown at the Corozal Substation were used for this study. The fruit was harvested at 5 and 7 months after fruit set date. Clean fruit was stored in polyethylene gags at 7° C and 90% relative humidity for 70 days. Differences in quality and chemical composition of the five clones of fruit were studied. Appearance and flavor of the fruit were found acceptable throughout the storage period. However, fruit stored between 25 and 55 days, regardless of the age of the fruit at harvesting, was preferred. The gas chromatographic pattern of peel oil of the fruit was similar for all clones. Higher concentrations were found in some fractions from the 7-month harvest. No significant difference was found in the flavor of the five clones. A decrease in the percentage of reducing and total sugars was noticed during the first month of storage in fruit harvested 5 months after fruit set, in contrast to an increase in the percentage of total sugars in fruit harvested 7 months after fruit set. Weight loss of fruit throughout the storage period was less than 1% for all clones, irrespective of their age at harvest. In general, there were more significant differences in chemical composition with respect to clones of fruit harvested at 7 months than those harvested at 5 months after fruit set.


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