Expression of the Rhizobium leguminosarum biovar phaseoli melA Gene in Other Rhizobia Does Not Require the Presence of the nifA Gene

1997 ◽  
Vol 24 (2) ◽  
pp. 195 ◽  
Author(s):  
Teresa Cubo ◽  
Francisco Romero ◽  
Jose M. Vinardell ◽  
Jose E. Ruiz-Sainz
Keyword(s):  
Rhizobium Leguminosarum ◽  
Regulatory Gene ◽  
Culture Conditions ◽  
Pigment Production ◽  
Liquid Media ◽  
Melanin Production ◽  
Melanin Biosynthesis ◽  
Tyrosinase Gene ◽  
Solid Media ◽  
Rhizobium Strains

Many different Rhizobium strains produce melanin (Mel+) when grown on solid media supplemented with L-tyrosine. The composition of the media and the culture conditions are of great importance for pigment production. Previous reports showed that some Rhizobium leguminosarum biovar phaseoli strains that produce the pigment in complete solid media (TY) failed to produce the pigment in minimal media (SY) supplemented with L-tyrosine or in TY liquid media. In this paper we have investigated different R. fredii, R. meliloti, R. etli and R. leguminosarum bv. trifolii and phaseoli strains (all of them Mel+ in solid media) for their ability to produce the pigment in liquid media. All Rhizobium species tested, except Rhizobium etli, were Mel+ in liquid media and in all cases the pigment yielded maximum absorption peaks at 280 and 315 nm. Melanin production by other bacteria (such as Vibrio, Streptomyces or Azospirillum) is enhanced by the presence of amino acids other that tyrosine. In this paper we show that the addition of L-methionine, which is not a precursor of rhizobial melanins, stimulated pigment production by Rhizobium cultures supplemented with L-tyrosine. The role of melanin production by Rhizobium strains is unclear. One hypothesis is that the Rhizobium tyrosinase, a bifunctional copper-containing enzyme that is essential for melanin biosynthesis, could detoxify polyphenolic compounds which might accumulate in senescing nodules. We show here that R. etli and R. fredii bacteroids produced melanin, which supports the idea that bacteroids contain the enzyme tyrosinase. Previous reports showed that, in R. leguminosarum bv. phaseoli strain 8002, the expression of the tyrosinase gene (melA) is dependent on the presence of nifA, a regulatory gene that is located in the symbiotic plasmid. However, transfer of R. leguminosarum bv. phaseoli melA gene to pSym-cured derivatives of R. leguminosarum bv. trifolii and viciae, R. fredii and Rhizobium sp. (Hedysarum) produced Mel+ transconjugants. DNA-hybridisation experiments showed that the pSym-cured strains did not contain any copy of nifA. Therefore, in contrast to the results reported on R. leguminosarum bv. phaseoli strain 8002, the expression of the melA gene in other rhizobia is not nifA-dependent. Key words: Rhizobium, melanin.

Comparison of media used to evaluateRhizobium leguminosarumbivarviciaefor phosphate-solubilizing ability

2009 ◽  
Vol 55 (7) ◽  
pp. 910-915 ◽  
Author(s):  
Jia Xie ◽  
J. Diane Knight ◽  
Mary E. Leggett
Keyword(s):  
Rhizobium Leguminosarum ◽  
Liquid Media ◽  
Solid Media ◽  
National Botanical Research Institute ◽  
Botanical Research ◽  
Phosphate Solubilizing ◽  
Ultimate Objective ◽  
Single Medium ◽  
Phosphate Medium ◽  
Ph Concentration

Rhizobium leguminosarum is well known for its ability to fix nitrogen (N). In addition, its capacity to solubilize phosphate (Ph) has been receiving attention in recent years. Our ultimate objective was to select a R. leguminosarum bv. viciae isolate with superior Ph-solubilizing ability. The first step was to identify a culture medium that is sensitive and effective in identifying the ability of R. leguminosarum bv. viciae isolates to solubilize Ph. Thirty isolates were evaluated for Ph solubilization in broth and on solid formulations of three media: yeast mannitol extract (YEM), National Botanical Research Institute phosphate nutrient medium (MNBRI), and Pikovskaya phosphate medium (PVK). All media contained 5 g/L CaHPO4as the only phosphorus (P) source. All 30 isolates increased the Ph concentration in liquid cultures, but the amount of Ph released into solution by individual isolates varied from one medium to another. In contrast, only a subset of the 30 isolates solubilized Ph on the solid cultures. Furthermore, some of the isolates that were able to solubilize Ph were only able to do so on a single medium. Regression analysis revealed no relationship between the Ph concentration in the liquid media and the zones of clearing on the solid media (p > 0.05). Although the pH of all of the liquid media dropped after 12 days of growth of the isolates, a relationship between Ph concentration and pH existed only for the MNBRI medium (r2= 0.485, p < 0.001). Increasing the amount of N in the MNBRI medium from 0.1 g/L of (NH4)2SO4to 0.5 g/L of (NH4)2SO4did not affect the amount of Ph in solution, but it profoundly reduced the survival of the R. leguminosarum by approximately 50-fold. Consequently, the surviving bacteria were either more efficient at solubilizing Ph in the high N media or organic acids released from the lysis of the dead cells solubilized the CaHPO4source.

scholarly journals Detection the role of physiological factors to produce carotenoid pigment in Staphylococcus aureus

2019 ◽  
Vol 24 (7) ◽  
pp. 6
Author(s):  
Ghada A. Mohammad ◽  
Suhair Taha Daod
Keyword(s):  
Staphylococcus Aureus ◽  
Ph Value ◽  
Negative Impact ◽  
Culture Media ◽  
Culture Conditions ◽  
Pigment Production ◽  
Carotenoid Pigment ◽  
Physiological Factors ◽  
Solid Media

Three Staphylococcus aureus isolates were used in the present study for extraction and quantitation of carotenoid pigment production. Different culture conditions were used to determine optimum pigmentation such as type of culture media, different pH values, temperature, and finally daily bacterial sub-culturing for more than 2 weeks. Nutrient agar was found to be the best medium with the highest production (1.09). Optimum pH value was 6.5 and gave (1.8) carotenoid. Also results showed that pigment was produced at 37o C more than at 42oC. Daily repeated sub culturing had a negative impact on pigment production. Colonies gradualy lost pigmentation and became white in color. Also, sub-culturing was shown to affect the volume of the colonies as they became smaller on solid media.    http://dx.doi.org/10.25130/tjps.24.2019.122

scholarly journals Assessment of Genetic Diversity and Symbiotic Efficiency of Selected Rhizobia Strains Nodulating Lentil (Lens culinaris Medik.)

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 15
Author(s):  
Badreddine Sijilmassi ◽  
Abdelkarim Filali-Maltouf ◽  
Hassan Boulahyaoui ◽  
Aymane Kricha ◽  
Kenza Boubekri ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Phylogenetic Analysis ◽  
16S Rrna ◽  
Rhizobium Leguminosarum ◽  
Sequence Similarity ◽  
P Value ◽  
Rrna Gene ◽  
Research Station ◽  
Symbiotic Efficiency ◽  
Rhizobium Strains

A total of 14 Rhizobium strains were isolated from lentil accessions grown at the ICARDA experimental research station at Marchouch in Morocco and used for molecular characterization and symbiotic efficiency assessment. Individual phylogenetic analysis using the 16S rRNA gene, house-keeping genes rpoB, recA, and gyrB, and symbiotic genes nodD and nodA along with Multilocus Sequence Analysis (MLSA) of the concatenated genes (16S rRNA-rpoB-recA-gyrB) was carried out for the identification and clustering of the isolates. The symbiotic efficiency of the strains was assessed on three Moroccan lentil cultivars (Bakria, Chakkouf, and Zaria) based on the number of nodules, plant height, plant dry weight, and total nitrogen content in leaves. The results showed that the individual phylogenetic analysis clustered all the strains into Rhizobium laguerreae and Rhizobium leguminosarum with sequence similarity ranging from 94 to 100%, except one strain which clustered with Mesorhizobium huakuii with sequence similarity of 100%. The MLSA of the concatenated genes and the related percentages of similarity clustered these strains into two groups of Rhizobium species, with one strain as a new genospecies when applying the threshold of 96%. For symbiotic efficiency, the Bakria variety showed the best association with 10 strains compared to its non-inoculated control (p-value ≤ 0.05), followed by Chakkouf and Zaria. The present study concluded that the genetic diversity and the symbiotic efficiency of Rhizobium strains appeared to be mainly under the control of the lentil genotypes.

scholarly journals Identification and phenotypic plasticity of Pseudanabaena catenata from the Svalbard archipelago

2017 ◽  
Vol 38 (4) ◽  
pp. 445-458 ◽  
Author(s):  
Zoya Khan ◽  
Wan Maznah Wan Omar ◽  
Faradina Merican Mohd Sidik Merican ◽  
Asmimie Asmawarnie Azizan ◽  
Choon Pin Foong ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Apical Cell ◽  
High Arctic ◽  
Culture Conditions ◽  
Rrna Gene ◽  
Molecular Characterisation ◽  
Liquid Media ◽  
Svalbard Archipelago ◽  
Temperature Regimes ◽  
Cell Dimensions

Abstract A filamentous benthic cyanobacteria, strain USMAC16, was isolated from the High Arctic Svalbard archipelago, Norway, and a combination of morphological, ultrastructural and molecular characterisation (16S rRNA gene sequence) used to identify to species level. Cell dimensions, thylakoid arrangement and apical cell shape are consistent with the Pseudanabaena genus description. The molecular characterisation of P. catenata gave 100% similarity with Pseudanabaena catenata SAG 1464-1, originally reported from Germany. Strain USMAC16 was cultured under a range of temperature and photoperiod conditions, in solid and liquid media, and harvested at exponential phase to examine its phenotypic plasticity. Under different culture conditions, we observed considerable variations in cell dimensions. The longest cell (5.91±0.13 μm) was observed at 15°C under 12:12 light:dark, and the widest cell (3.24±0.06 μm) at 4°C under 12:12 light: dark in liquid media. The study provides baseline data documenting the morphological variation of P. catenata in response to changing temperature regimes.

Melanization in albino mice transformed by introducing cloned mouse tyrosinase gene

Development ◽  
1990 ◽  
Vol 108 (2) ◽  
pp. 223-227 ◽  
Author(s):  
S. Tanaka ◽  
H. Yamamoto ◽  
S. Takeuchi ◽  
T. Takeuchi
Keyword(s):  
Transgenic Mice ◽  
Histological Analysis ◽  
Pigment Production ◽  
Flanking Sequence ◽  
First Report ◽  
Tyrosinase Gene ◽  
Flanking Region ◽  
Albino Mice ◽  
Successful Expression

We introduced a mouse tyrosinase minigene, mg-Tyrs-J, in which the authentic genomic 5′ non-coding flanking sequence was fused to a mouse tyrosinase cDNA, into fertilized egges of albino mice. Of the 25 animals that developed from the injected eggs, four mice exhibited pigmented hair and eyes. Histological analysis of the transgenic mice revealed that the melanogenesis was restricted to hair bulbs and eyes. These results suggest that this minigene encodes active tyrosinase protein and that its 5′ flanking region contains the sequences regulating expression of mouse tyrosinase gene. This is the first report of a successful expression of tyrosinase gene and of pigment production in transgenic mice.

Recovery of Humic-Reducing Bacteria from a Diversity of Environments

1998 ◽  
Vol 64 (4) ◽  
pp. 1504-1509 ◽  
Author(s):  
John D. Coates ◽  
Debra J. Ellis ◽  
Elizabeth L. Blunt-Harris ◽  
Catherine V. Gaw ◽  
Eric E. Roden ◽  
...  
Keyword(s):  
Humic Substance ◽  
Electron Acceptor ◽  
Microbial Reduction ◽  
Acetate Oxidation ◽  
Liquid Media ◽  
Sedimentary Environments ◽  
Sediment Types ◽  
Solid Media ◽  
The Family ◽  
Reducing Bacteria

ABSTRACT To evaluate which microorganisms might be responsible for microbial reduction of humic substances in sedimentary environments, humic-reducing bacteria were isolated from a variety of sediment types. These included lake sediments, pristine and contaminated wetland sediments, and marine sediments. In each of the sediment types, all of the humic reducers recovered with acetate as the electron donor and the humic substance analog, 2,6-anthraquinone disulfonate (AQDS), as the electron acceptor were members of the familyGeobacteraceae. This was true whether the AQDS-reducing bacteria were enriched prior to isolation on solid media or were recovered from the highest positive dilutions of sediments in liquid media. All of the isolates tested not only conserved energy to support growth from acetate oxidation coupled to AQDS reduction but also could oxidize acetate with highly purified soil humic acids as the sole electron acceptor. All of the isolates tested were also able to grow with Fe(III) serving as the sole electron acceptor. This is consistent with previous studies that have suggested that the capacity for Fe(III) reduction is a common feature of all members of theGeobacteraceae. These studies demonstrate that the potential for microbial humic substance reduction can be found in a wide variety of sediment types and suggest thatGeobacteraceae species might be important humic-reducing organisms in sediments.

scholarly journals Usnic acid and Triacylglycerides Production by the Cultured Lichen Mycobiont of Ramalina celastri

2014 ◽  
Vol 9 (2) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Alejandra T. Fazio ◽  
Mónica T. Adler ◽  
Marta S. Maier
Keyword(s):  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
Usnic Acid ◽  
Culture Conditions ◽  
High Yield ◽  
Acid Methyl ◽  
Solid Media ◽  
Lichen Thallus ◽  
The Impact ◽  
Very High

A strain of the lichen mycobiont of Ramalina celastri, isolated from ascospores, was cultured axenically on two solid media containing high amounts of the carbon source: sucrose in MY10 and mannitol in BMRM. Usnic acid, the major cortical lichen metabolite, was produced by the colonies grown on MY10, with a very high yield (7.9%) in comparison with that in the lichen thallus. Mycelia grown on BMRM did not produce the lichen secondary metabolite and rendered triacylglycerides (8.5%) instead. Analysis by GC-MS of the fatty acid methyl esters revealed the presence of oleic, palmitic and stearic acids as the main triacylglyceride constituents. The present results highlight the impact of the culture conditions on the lichen mycobiont secondary metabolism and confirm that MY10 is a useful medium to obtain usnic acid from mycobionts in the laboratory.

Potent Melanin Production Enhancement of Human Tyrosinase Gene by Tat and an Entrapment in Elastic Cationic Niosomes: Potential Application in Vitiligo Gene Therapy

2012 ◽  
Vol 80 (6) ◽  
pp. 953-960
Author(s):  
Jiradej Manosroi ◽  
Narinthorn Khositsuntiwong ◽  
Friedrich Götz ◽  
Rolf G. Werner ◽  
Worapaka Manosroi ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Potential Application ◽  
Melanin Production ◽  
Tyrosinase Gene ◽  
Cationic Niosomes ◽  
Human Tyrosinase

scholarly journals A vector for studying plasmid stability functions in Streptomyces

1988 ◽  
Vol 51 (1) ◽  
pp. 71-74 ◽  
Author(s):  
Kevin Kendall ◽  
John Cullum
Keyword(s):  
Copy Number ◽  
Stability Region ◽  
Selectable Marker ◽  
Plasmid Stability ◽  
Stability Function ◽  
Melanin Production ◽  
Stability Functions ◽  
Tyrosinase Gene ◽  
Copy Number Plasmid ◽  
Low Copy Number

SummaryWe constructed a cloning vector (pMT603) based on the low copy number plasmid SCP2*. pMT6O3 is unstable because it lacks the SCP2* stability region and carries the selectable marker thiostrepton-resistance and a tyrosinase gene which results in melanin production. This allows easy testing of plasmid stability and we demonstrated its usefulness by cloning a plasmid stability function.

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