scholarly journals Molybdate Reduction to Molybdenum Blue by an Antarctic Bacterium

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
S. A. Ahmad ◽  
M. Y. Shukor ◽  
N. A. Shamaan ◽  
W. P. Mac Cormack ◽  
M. A. Syed
Keyword(s):  
Gel Filtration ◽  
Potassium Cyanide ◽  
Sodium Molybdate ◽  
Identification System ◽  
Optimal Conditions ◽  
Molybdenum Blue ◽  
Microbial Identification ◽  
Molecular Phylogenetic ◽  
Initial Ph ◽  
Reducing Activity

A molybdenum-reducing bacterium from Antarctica has been isolated. The bacterium converts sodium molybdate or Mo6+to molybdenum blue (Mo-blue). Electron donors such as glucose, sucrose, fructose, and lactose supported molybdate reduction. Ammonium sulphate was the best nitrogen source for molybdate reduction. Optimal conditions for molybdate reduction were between 30 and 50 mM molybdate, between 15 and 20°C, and initial pH between 6.5 and 7.5. The Mo-blue produced had a unique absorption spectrum with a peak maximum at 865 nm and a shoulder at 710 nm. Respiratory inhibitors such as antimycin A, sodium azide, potassium cyanide, and rotenone failed to inhibit the reducing activity. The Mo-reducing enzyme was partially purified using ion exchange and gel filtration chromatography. The partially purified enzyme showed optimal pH and temperature for activity at 6.0 and 20°C, respectively. Metal ions such as cadmium, chromium, copper, silver, lead, and mercury caused more than 95% inhibition of the molybdenum-reducing activity at 0.1 mM. The isolate was tentatively identified asPseudomonassp. strain DRY1 based on partial 16s rDNA molecular phylogenetic assessment and the Biolog microbial identification system. The characteristics of this strain would make it very useful in bioremediation works in the polar and temperate countries.

scholarly journals Kinetics of Molybdenum Reduction to Molybdenum Blue byBacillussp. Strain A.rzi

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
A. R. Othman ◽  
N. A. Bakar ◽  
M. I. E. Halmi ◽  
W. L. W. Johari ◽  
S. A. Ahmad ◽  
...  
Keyword(s):  
Experimental Data ◽  
Electron Transport ◽  
Potassium Cyanide ◽  
Antimycin A ◽  
Strong Inhibition ◽  
Positive Bacterium ◽  
Molybdenum Blue ◽  
Ideal Tool ◽  
Reducing Activity ◽  
Kinetics Of

Molybdenum is very toxic to agricultural animals. Mo-reducing bacterium can be used to immobilize soluble molybdenum to insoluble forms, reducing its toxicity in the process. In this work the isolation of a novel molybdate-reducing Gram positive bacterium tentatively identified asBacillussp. strain A.rzi from a metal-contaminated soil is reported. The cellular reduction of molybdate to molybdenum blue occurred optimally at 4 mM phosphate, using 1% (w/v) glucose, 50 mM molybdate, between 28 and 30°C and at pH 7.3. The spectrum of the Mo-blue product showed a maximum peak at 865 nm and a shoulder at 700 nm. Inhibitors of bacterial electron transport system (ETS) such as rotenone, sodium azide, antimycin A, and potassium cyanide could not inhibit the molybdenum-reducing activity. At 0.1 mM, mercury, copper, cadmium, arsenic, lead, chromium, cobalt, and zinc showed strong inhibition on molybdate reduction by crude enzyme. The best model that fitted the experimental data well was Luong followed by Haldane and Monod. The calculated value for Luong’s constantspmax,Ks,Sm, andnwas 5.88 μmole Mo-blue hr−1, 70.36 mM, 108.22 mM, and 0.74, respectively. The characteristics of this bacterium make it an ideal tool for bioremediation of molybdenum pollution.

scholarly journals Identification of Three Strains of Mycobacterium Species Isolated from Clinical Samples Using Fatty Acid Methyl Ester Profiling

2003 ◽  
Vol 31 (2) ◽  
pp. 133-140 ◽  
Author(s):  
A Ozbek ◽  
O Aktas
Keyword(s):  
Fatty Acid ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Cellular Fatty Acid ◽  
Clinical Samples ◽  
Identification System ◽  
Cyclopropane Fatty Acid ◽  
Mycobacterium Species ◽  
Microbial Identification ◽  
Acid Methyl

The cellular fatty acid profiles of 67 strains belonging to three different species of the genus Mycobacterium were determined by gas chromatography of the fatty acid methyl esters, using the MIDI Sherlock® Microbial Identification System (MIS). The species M. tuberculosis, M. xenopi and M. avium complex were clearly distinguishable and could be identified based on the presence and concentrations of 12 fatty acids: 14:0, 15:0, 16:1ω7c, 16:1ω6c, 16:0, 17:0, 18:2ω6,9c, 18:1ω9c, 18:0, 10Me-18:0 tuberculostearic acid, alcohol and cyclopropane. Fatty acid analysis showed that there is great homogeneity within and heterogeneity between Mycobacterium species. Thus the MIS is an accurate, efficient and relatively rapid method for the identification of mycobacteria.

The first study on the bacterial flora of the european spruce bark beetle, Dendroctonus micans (Coleoptera: Scolytidae)

Biologia ◽  
2006 ◽  
Vol 61 (6) ◽  
Author(s):  
Hüseyin Yilmax ◽  
Kazım Sezen ◽  
Hatice Kati ◽  
Zihni Demirbağ
Keyword(s):  
Bark Beetle ◽  
Micrococcus Luteus ◽  
Bacterial Flora ◽  
Biochemical Properties ◽  
Identification System ◽  
Dendroctonus Micans ◽  
Microbial Identification ◽  
Spruce Bark Beetle ◽  
Spruce Bark ◽  
European Spruce Bark Beetle

AbstractThe European spruce bark beetle, Dendroctonus micans Kugelann (Coleoptera, Scolytidae), is one of the most serious pests of oriental spruce (Picea orientalis L.) in Turkey. In this study, we investigated bacterial flora of D. micans collected from different populations of the forests of Eastern Black Sea Region of Turkey from 2002 to 2004. Seven different bacteria were isolated from healthy, diseased and dead specimens based on the color of colony and morphology. According to morphological, physiological and biochemical properties, metobolic enyzme profile by BIOLOG microtiter plate system, and total cellular fatty acid profile by Microbial Identification System (MIS), isolates were identified as Micrococcus luteus, Bacillus thuringiensis subsp. morrisoni, Serratia grimesii, Enterobacter cloaceae, Enterobacter intermedius, Streptococcus sp. and Pseudomonas putida. This is the first study on the bacterial flora of D. micans.

scholarly journals First Report of a Fruit Rot of Pumpkin Caused by Acidivorax avenae subsp. citrulli in Georgia

Plant Disease ◽  
1999 ◽  
Vol 83 (2) ◽  
pp. 199-199 ◽  
Author(s):  
D. B. Langston ◽  
R. D. Walcott ◽  
R. D. Gitaitis ◽  
F. H. Sanders
Keyword(s):  
Polyclonal Antibodies ◽  
Pcr Amplification ◽  
Tween 80 ◽  
Soft Rot ◽  
Fruit Rot ◽  
Identification System ◽  
Banding Patterns ◽  
First Report ◽  
Microbial Identification ◽  
Necrotic Spots

In September 1998, a fruit rot was reported affecting pumpkin (Cucurbita pepo) in a commercial field in Terrell Co., Georgia. Symptoms on the surface of fruit occurred as round, necrotic spots or cracks a few millimeters in diameter. With age, the tissue surrounding these lesions became soft and wrinkled. A soft rot expanded into the flesh of the pumpkin, originating from the lesions observed on the surface. In time, infected pumpkins totally collapsed. V-shaped, necrotic lesions occurred at the margin of the leaf and extended inward toward the mid-rib. Samples were collected from the field and bacteria were isolated from fruit and leaf lesions onto King's medium B (1). The bacterium isolated was rod shaped, gram negative, nonflourescent, oxidase positive, Tween 80 positive, carboxymethyl cellulose positive, β-OH butyrate positive, and malonate negative. The bacterium reacted positively with polyclonal antibodies specific for the watermelon fruit blotch pathogen Acidivorax avenae subsp. citrulli and was identified as A. avenae subsp. citrulli by MIDI (Microbial Identification System, Newark, DE) according to statistical analysis of fatty acid data. Results from polymerase chain reaction (PCR) amplification of the bacterium isolated from pumpkin yielded 360-bp fragments that, when digested with the restriction enzyme HaeIII, had DNA banding patterns identical to those of stock A. avenae subsp. citrulli DNA. Koch's postulates were completed successfully with 2-week-old watermelon seedlings. This is the first report of A. avenae subsp. citrulli causing fruit rot of pumpkin in Georgia. Reference: (1) E. O. King et al. J. Lab. Clin. Med. 44:301, 1954.

scholarly journals Screening of Antagonistic Bacteria from Endophytes against Walnut Blight Pathogen Xanthomonas arboricola pv. juglandis

2021 ◽  
Author(s):  
Benzhong Fu ◽  
Lei Yu ◽  
Bokai Wang ◽  
Cao Zheng
Keyword(s):  
Endophytic Bacteria ◽  
Fungal Pathogens ◽  
Acid Methyl Ester ◽  
Identification System ◽  
Bacterial Disease ◽  
Dual Culture ◽  
Antagonistic Bacteria ◽  
Microbial Identification ◽  
Xanthomonas Arboricola ◽  
Walnut Blight

Walnut blight caused by Xanthomonas arboricola pv. juglandis (Xaj) is the most important bacterial disease in walnut production worldwide. To seek biocontrol agents against Xaj, we screened 152 endophytic bacteria isolated from 87 plants. Through dual-culture method screening, we obtained four antagonistic bacteria, ATE17, BME17, CIE17, and OFE17 which were isolated from Amaranthus tricolor, Bambusa multiplex, Canna indica, and Osmanthus fragrans plants respectively. The inhibition ratios of ATE18, BME17, CIE18, and OFE17 against Xaj on plates were 1.5, 1.6, 1.3, and 1.6, respectively. These indicated they have good biocontrol potential for walnut bacterial blight. Subsequently, the four endophytic bacteria were identified by morphology, Gram staining, Microbial Identification System (fatty acid methyl ester analysis), as well as 16S rDNA and gyrB sequencing. It turns out that all four strains were identified as Bacillus sp. Furthermore, the two strains BME17 and OFE17 can suppress multiple plant fungal pathogens and bacterial pathogens on plates.

scholarly journals Characterization of Melanoidins and Color Development in Dulce de Leche, a Confectionary Dairy Product With High Sucrose Content: Evaluation of pH Effect, an Essential Manufacturing Process Parameter

2021 ◽  
Vol 8 ◽  
Author(s):  
Analía Rodríguez ◽  
Patricia Lema ◽  
María Inés Bessio ◽  
Guillermo Moyna ◽  
Cristina Olivaro ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Ph Effect ◽  
Dairy Product ◽  
Gel Filtration ◽  
Significant Degree ◽  
Product Analysis ◽  
Molecular Weights ◽  
Ph Values ◽  
Initial Ph

The effect on color of the initial pH employed in dulce de leche (DL) production was evaluated through physicochemical and spectroscopical characterization of the melanoidins formed in the process. Melanoidins originated at pH values of 6.5, 7.0, and 7.5, and they were released by the enzymatic hydrolysis of the protein backbone and purified by gel filtration. They showed a significant degree of polydispersity, in general, with molecular weights (MWs) below 1,800 Da. DL produced at a higher pH released melanoidins with higher average MW after the enzymatic hydrolysis. They also presented darker colors (dE*ab, C*), more closely resembling those typical of the commercial product. Analysis of the fractions isolated by gel filtration using HPLC-DAD and multinuclear NMR showed an heterogeneous and complex composition. Even though structurally related, the 1H NMR spectra of melanoidins showed a higher degree of aromaticity at higher pH values. In conclusion, the pH employed in DL production affects the amount and structure of the colored products originated by MR reactions, and thus the color of the final product.

scholarly journals Occurrence of Bacterial Stem Rot, Caused by Erwinia chrysanthemi, on Field-Grown Tomato in Florida

Plant Disease ◽  
1998 ◽  
Vol 82 (7) ◽  
pp. 831-831 ◽  
Author(s):  
D. O. Chellemi ◽  
H. A. Dankers ◽  
K. Hill ◽  
R. E. Cullen ◽  
G. W. Simone ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Methyl Esters ◽  
Sole Source ◽  
Erwinia Chrysanthemi ◽  
Identification System ◽  
Bacterial Cells ◽  
Sterile Water ◽  
Microbial Identification ◽  
Pure Cultures ◽  
Tomato Isolate

In September 1997, wilted 4-week-old tomato (Lycopersicon esculentum Mill.) plants were observed in a commercial production field in St. Lucie County, FL. Closer inspection of affected plants revealed hollow stems and petioles with dark, water-soaked lesions. Diseased tissue was macerated and streaked onto nutrient agar (NA) and crystal violet pectate (CVP) agar. After incubation for 2 days at 30°C, isolates produced pits on the CVP agar. Isolates were transferred onto NA and the incubation and transfer procedure was performed two additional times to obtain pure cultures. Suspensions of bacterial cells were injected into tomato and tobacco leaves to test for a hypersensitive or pathogenic reaction. Isolates produced collapsed necrotic tissue on tomato while no reaction was observed on tobacco. Tests for differentiating species and subspecies in the ‘carotovora’ group of Erwinia were conducted following the protocol of Dickey and Kelman (1). With known cultures of E. carotovora subsp. carotovora and E. chrysanthemi as controls, the isolate from tomato was determined to function as a facultative anaerobe, utilize asparagine as a sole source of carbon and nitrogen, and give positive reactions for pectate degradation, phosphatase, and growth at 37°C. Known cultures of E. carotovora subsp. carotovora, E. chrysanthemi, and the tomato isolate were grown on trypticase soy broth agar for 24 h at 28°C and their cellular fatty acids derivatized to fatty acid methyl esters (FAMEs). Statistical analyses of FAME profile data (MIDI Microbial Identification System, Newark, DE, version 3.60) identified the tomato isolate as Erwinia chrysanthemi. Pathogenicity was determined by inoculating 50-day-old tomato plants (cv. SunPride) with a suspension of E. chrysanthemi obtained from nutrient broth plates incubated at 24°C for 60 h. Three plants each were inoculated with the E. chrysanthemi identified from tomato, sterile water, and known cultures of E. chrysanthemi and E. carotovora subsp. carotovora by placing a drop at the junction of the petiole and stem and passing a sterile needle through the drop into the stem. Plants were maintained in a greenhouse. Dark, water-soaked cankers were observed on the stems of plants inoculated with E. chrysanthemi, including the tomato isolate and E. carotovora subsp. carotovora, after 7 days. No symptoms were observed on plants inoculated with sterile water. Reisolation of the pathogen and identification was performed with tissue from one of the symptomatic inoculated plants. Analyses of FAMEs confirmed E. chrysanthemi as the causal agent. This is the first report of E. chrysanthemi causing a vascular disease of field-grown tomato in Florida. Reference: (1) R. S. Dickey and A. Kelman. 1988. Pages 44–59 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. N. W. Schaad, ed. American Phytopathological Society, St. Paul, MN.

scholarly journals Occurrence of Bacterial Stripe of Pearl Millet in Georgia

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 326-326
Author(s):  
R. Gitaitis ◽  
J. Wilson ◽  
R. Walcott ◽  
H. Sanders ◽  
W. Hanna
Keyword(s):  
Pearl Millet ◽  
Sweet Corn ◽  
Pennisetum Glaucum ◽  
Methyl Esters ◽  
The United States ◽  
Negative Control ◽  
Identification System ◽  
Breeding Lines ◽  
Microbial Identification ◽  
Atypical Symptoms

Bacterial stripe, caused by Acidovorax avenae subsp. avenae, was observed on breeding lines of pearl millet (Pennisetum glaucum (L.) R. Br.) in Georgia in 1999 and 2001. A gram-negative, oxidase-positive, rod-shaped bacterium that produced circular, cream-colored, nonfluorescent, butyrous colonies with entire margins on King's medium B was consistently isolated from leaf lesions. The bacterium was identified as A. avenae subsp. avenae by gas-chromatography of extracted, whole-cell, fatty acid methyl esters using the Sherlock Microbial Identification System (MIDI, Newark, DE) and by substrate utilization patterns using the Biolog Identification System (Biolog Inc., Hayward, CA). Isolates from pearl millet produced amplicons of expected size (360 bp) from 16S rDNA after conducting polymerase chain reaction (PCR) with primers WFB1 and WFB2, which are specific for A. avenae. When bacterial suspensions of 1 × 108 CFU/ml were infiltrated into the intercellular spaces of leaves of pearl millet seedlings in the greenhouse, typical water-soaked, reddish-brown stripes developed and were identical to those observed in the field. In contrast to previous reports (1), the pearl millet strains produced atypical symptoms on sweet corn (cvs. Merit and Primetime). Necroses were restricted, lacked customary water-soaking, and were similar to symptoms produced by the watermelon pathogen, A. avenae subsp. citrulli, which was used as a negative control. In contrast, three strains of A. avenae subsp. avenae previously isolated from corn in Georgia produced typical water-soaked stripes in both millet and the sweet corn ‘Merit’. However, like the millet strains, A. avenae subsp. avenae strains from corn produced atypical symptoms on the sweet corn ‘Primetime’. Using immunomagnetic separation and PCR (2), A. avenae subsp. avenae was detected in remaining samples of pearl millet seed planted in Georgia in 2001, as well as in remnant samples of seed sent to Puerto Rico for increase in 2000. The A. avenae subsp. avenae strain recovered from seed was identified by the methods listed above, and in the greenhouse it was identified by the production of typical water-soaked stripes after inoculation of pearl millet. This is the first report of A. avenae subsp. avenae infecting pearl millet in the United States. The detection and distribution of seedborne inoculum in breeding lines is significant since the program at Tifton represents a major effort by the U.S. Department of Agriculture to develop higher-yielding, disease-resistant pearl millet hybrids. Furthermore, the strains from pearl millet appear to be different from previous A. avenae subsp. avenae strains isolated from corn in Georgia, because they did not produce typical disease symptoms when infiltrated in corn leaves. References: (1) L. E. Claflin et al. Plant Dis. 73:1010, 1989. (2) R. R. Walcott and R. D. Gitaitis. Plant Dis. 84:470, 2000.

scholarly journals Determination of Whole-Cell Fatty Acid Profiles for the Characterization and Differentiation of Isolates of Rhizoctonia solani AG-4 And AG-7

Plant Disease ◽  
2000 ◽  
Vol 84 (7) ◽  
pp. 785-788 ◽  
Author(s):  
R. E. Baird ◽  
R. D. Gitaitis ◽  
D. E. Carling ◽  
S. M. Baird ◽  
P. J. Alt ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Rhizoctonia Solani ◽  
Euclidean Distance ◽  
Methyl Esters ◽  
Principal Component ◽  
Identification System ◽  
Microbial Identification ◽  
Euclidean Distances

Fatty acid methyl esters (FAMEs) of isolates of Rhizoctonia solani AG-4 and AG-7 were characterized by gas chromatography and analyzed with Microbial Identification System software. Palmitic, stearic, and oleic acids were common in all isolates from both anastomosis groups (AGs) and accounted for 95% of the C14 to C18 fatty acids present. Oleic acid, most common in both R. solani AG-4 and AG-7 isolates, accounted for the greatest percentages of total FAMEs. The presence, quantities, or absence of individual fatty acids could not be used for distinguishing AG-4 and AG-7 isolates. Anteisopentadecanoic and 9-heptadecanoic acids, however, were specific to all three AG-7 isolates from Japan but absent in other AG-7 isolates and all AG-4 isolates. Pentadecanoic acid occurred in only two of the R. solani AG-4 isolates, but was not found in any of the AG-7 isolates. The AG-4 isolates could be distinguished from AG-7 isolates when quantities of FAMEs and key FAME ratios were analyzed with cluster analysis and principle components were plotted. Isolates of AG-7 from Arkansas, Indiana, and Georgia appeared to be more closely related to each other than to AG-7 isolates from Japan and Mexico. These differences in FAMEs were sufficiently distinct that isolate geographical variability could be determined. A dendrogram analysis cluster constructed from the FAMEs data showed results similar to that of the principal component analysis. Euclidean distances of total AG-4 isolates were distinct from total AG-7 isolates. The Arkansas and Indiana AG-7 isolates had a similar Euclidean distance to each another but the percentages were different for the AG-7 isolates from Japan and Mexico. In conclusion, variability of the FAMEs identified in this study would not be suitable as the main diagnostic tool for distinguishing individual isolates of R. solaniAG-4 from AG-7.

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