Water quality. Enumeration of culturable micro-organisms. Colony count by inoculation in a nutrient agar culture medium

1999 ◽  
Keyword(s):  
Water Quality ◽  
Culture Medium ◽  
Nutrient Agar ◽  
Colony Count ◽  
Agar Culture ◽  
Micro Organisms

Chemical control of fungal growth and ochratoxin A production by Aspergillus isolated from Moroccan grapes

2018 ◽  
Vol 7 (2) ◽  
pp. 84-91
Author(s):  
Adil Laaziz ◽  
Souad Qjidaa ◽  
Yousra El Hammoudi ◽  
Abdelouahed Hajjaji ◽  
Amina Bouseta
Keyword(s):  
Ochratoxin A ◽  
Radial Growth ◽  
Culture Medium ◽  
Fungal Growth ◽  
Sublethal Concentration ◽  
Agar Culture ◽  
Total Inhibition ◽  
Yeast Autolysate ◽  
Germination And Growth ◽  
Czapek Yeast Autolysate Agar

The aim of this study was to evaluate the effect of three fungicides azoxystrobin (Ortiva), hexaconazole (Hexa) and pyrimethanil (Pyrus) for their ability to inhibit the radial growth and ochratoxin A (OTA) production by five ochratoxigenic strains of Aspergillus carbonarius and A. niger previously iso-lated from Moroccan grapes. Our results showed that, the addition of the fungicides to the Czapek Yeast Autolysate agar culture medium reduced the growth of the ochratoxigenic strains. Pyrimethanil caused total inhibition of spore germination and growth of the five strains, for all dose tested. Where-as hexaconazole totally inhibited the growth of 4 strains and gave growth for the MUCL 49227 strain (2.67 mm/day) at sublethal concentration. The reduction in radial growth was less marked for azoxystrobin, with growth rate varying between 0 and 6.37 mm/day depending on the strain and the azoxystrobin concentration. Analysis of variance showed that the effect of single factors (fungicides, concentration and strain) and their interactions on growth and OTA production were highly significant (P=0.000).These findings suggest that the use of tested fungicides have to potential for reduction in production of OTA.

scholarly journals Efficiency of Blotter test and agar culture medium to detect Fusarium graminearum and Pyricularia grisea in wheat seeds

2017 ◽  
Vol 39 (3) ◽  
pp. 297-302
Author(s):  
Meyriele Pires de Camargo ◽  
Maria Heloisa Duarte de Moraes ◽  
José Otávio Machado Menten
Keyword(s):  
Fusarium Graminearum ◽  
Culture Medium ◽  
Potato Dextrose Agar ◽  
Pyricularia Grisea ◽  
Agar Culture ◽  
Hypochlorite Solution ◽  
Three Samples ◽  
Seed Health ◽  
Incubation Temperatures ◽  
Wheat Seeds

Abstract: Seeds can be considered one of the most efficient forms to disseminate pathogens. Therefore, the use of healthy seeds is extremely important to establish a crop, and seed health testing must be performed to determine the seed sanitary quality. This study aimed to compare the efficiency of seed health testing to detect Pyricularia grisea and Fusarium graminearum in three samples of wheat seeds. Methods evaluated were Blotter test with freezing (BTF) and potato-dextrose-agar culture medium (PDA). The incubation temperatures were 20 ºC and 25 ºC. From each sample, a subsample was submitted to seed asepsis using hypochlorite solution (1%) and another analyzed without seed asepsis. The temperatures evaluated did not influence the detection of the pathogens. P. grisea incidence ranged from 4.5 to 17% with BTF without seed asepsis. The BTF with seed asepsis and PDA (with and without seed asepsis) presented pathogen incidence no higher than 1.5%. Moreover, results suggested that most part of P. grisea inoculum was presented externally on seed tissues. PDA medium was more efficient to detect F. graminearum, independently of seed asepsis. By this method, pathogen incidence ranged from 3 to 39%. F. graminearum incidence using BTF with seed asepsis varied from 0.5 to 1.5% and BTF without seed asepsis presented a pathogen incidence of 5.0 to 12.5%. The Blotter test with freezing was more efficient to detect P. grisea while the PDA medium was more efficient to detect F. graminearum.

Terpenoid quinones and steroids in the nutrition of Oxyrrhis marina

1971 ◽  
Vol 51 (2) ◽  
pp. 455-470 ◽  
Author(s):  
M. R. Droop ◽  
J. F. Pennock
Keyword(s):  
Growth Factors ◽  
Culture Medium ◽  
Water Soluble ◽  
The Other ◽  
Natural Sources ◽  
Oxyrrhis Marina ◽  
Nutritional Study ◽  
Axenic Conditions ◽  
Micro Organisms ◽  
Axenic Cultivation

INTRODUCTIONOxyrrhis marina Dujardin is among the few phagotrophic micro-organisms, and the only dinoflagellate with this mode of nutrition, to have been cultivated under axenic conditions. In common with most other phagotrophs studied, Oxyrrhis had to be supplied with a natural source of lipid growth factors for axenic cultivation, lemon rind or grass extracts in this instance (Droop, 1959). The eventual replacement of these natural sources by ubiquinone (Droop & Doyle, 1966) cleared the way for the development of a completely denned culture medium for Oxyrrhis and the completion of the nutritional study, the water-soluble nutrients having been fully worked out previously (Droop, 1959). However, identification of this requirement immediately raises two questions. The answer to the first, whether ubiquinone is the only lipid required, appears to be in the negative, and the details of an additional, fairly specific, steroid requirement are presented in the second part of this paper. The other question concerns the specificity of the quinone requirement. Is the quinone merely a convenient source of the benzene ring – mammals require at least one aromatic compound in the diet – or does it act as a true growth factor, in which case the requirement would be unique and would have more than protozoological interest?

scholarly journals Obtaining monokaryotic and dikaryotic mycelial cultures of two Amazonian strains of Geastrum (Geastraceae, Basidiomycota)

2020 ◽  
Vol 50 (1) ◽  
pp. 61-67
Author(s):  
Marcos Diones Ferreira SANTANA ◽  
Ruby VARGAS-ISLA ◽  
Janaina da Costa NOGUEIRA ◽  
Thiago ACCIOLY ◽  
Bianca Denise Barbosa da SILVA ◽  
...  
Keyword(s):  
Culture Medium ◽  
Culture Media ◽  
Brazilian Amazon ◽  
Potato Dextrose Agar ◽  
Morphological Description ◽  
Agar Culture ◽  
Biotechnological Potential ◽  
Sexual Crosses ◽  
High Diversity

ABSTRACT The high diversity of the genus Geastrum and the difficulty of obtaining mycelial cultures impairs the study of the ecophysiology and the exploration of the biotechnological potential of the taxon. In this study, different culture media were tested to obtain mycelial cultures for G. lloydianum and G. subiculosum collected in the Brazilian Amazon. Data on spore germination, and isolation of monokaryotic cultures and in vitro sexual reproduction are presented, as well as a brief morphological description of the cultures obtained. For both species, Potato Dextrose Agar (PDA) was the most promising of the tested culture media. The highest growth in agar culture ever recorded for this genus is reported (4.9 mm per week for G. lloydianum and 7.5 mm for G. subiculosum). In the PDA culture medium, spores germinated after 35-40 days of incubation and the isolation of monokaryotic cultures of the two species, as well as in vitro sexual crosses, were successfully performed.

scholarly journals Potabilidade da água de poços artesianos: diagnóstico de amostras dos municípios do Rio Grande do Sul

2019 ◽  
Vol 41 ◽  
pp. 1
Author(s):  
Sandra Cadore Peixoto ◽  
Carolina Denardi Merlugo ◽  
Anderson Maciel ◽  
Tiago Barboza Solner
Keyword(s):  
Water Quality ◽  
Ph Value ◽  
Iron Concentration ◽  
Rio Grande ◽  
Natural State ◽  
Human Consumption ◽  
Rio Grande Do Sul ◽  
Artesian Wells ◽  
Micro Organisms

Drinking water is all water for consumption. It must have certain amount of dissolved minerals, be free of toxic materials and micro-organisms. It is considered an indispensable resource for man. One of the main problems for the use of water is related to its contamination, that is, this resource has been polluted in such a way that it can no longer consume it in its natural state. However, despite all the efforts to store and reduce its consumption, it is becoming scarce and its quality deteriorates faster and faster. In this way, groundwater has become an important alternative for water supply to communities. Considering the relevance of this theme, this study seeks to make a diagnosis of the water quality of artesian wells of the Central Region of the State of Rio Grande do Sul, in order to prove the potability. For these determinations the experimental procedures were: determination of the pH value; turbidity; temperature; total solids dissolved; color; hardness and residual iron concentration. The evaluation of the results obtained in this study was based on the standards of potability established in Ordinance No. 2,914, of December 12, 2011, of the Ministry of Health, which establishes the procedures for control and surveillance of water quality for human consumption and its standard of potability.Drinking water is all water for consumption. It must have certain amount of dissolved minerals, be free of toxic materials and micro-organisms. It is considered an indispensable resource for man. One of the main problems for the use of water is related to its contamination, that is, this resource has been polluted in such a way that it can no longer consume it in its natural state. However, despite all the efforts to store and reduce its consumption, it is becoming scarce and its quality deteriorates faster and faster. In this way, groundwater has become an important alternative for water supply to communities. Considering the relevance of this theme, this study seeks to make a diagnosis of the water quality of artesian wells of the Central Region of the State of Rio Grande do Sul, in order to prove the potability. For these determinations the experimental procedures were: determination of the pH value; turbidity; temperature; total solids dissolved; color; hardness and residual iron concentration. The evaluation of the results obtained in this study was based on the standards of potability established in Ordinance No. 2,914, of December 12, 2011, of the Ministry of Health, which establishes the procedures for control and surveillance of water quality for human consumption and its standard of potability.

scholarly journals In Vitro Effect ofZingiber officinaleExtract on Growth ofStreptococcus mutansandStreptococcus sanguinis

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Arash Azizi ◽  
Shabnam Aghayan ◽  
Saeed Zaker ◽  
Mahdieh Shakeri ◽  
Navid Entezari ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Culture Medium ◽  
Zingiber Officinale ◽  
Bacterial Suspension ◽  
Tooth Decay ◽  
Agar Culture ◽  
Solid Agar ◽  
Vitro Effect ◽  
Serial Dilutions

Background and Objectives. Tooth decay is an infectious disease of microbial origin. Considering the increasing prevalence of antibiotic resistance due to their overuse and also their side effects, medicinal plants are now considered for use against bacterial infections. This study aimed to assess the effects of different concentrations ofZingiber officinaleextract on proliferation ofStreptococcus mutansandStreptococcus sanguinisin vitro.Materials and Methods. In this experimental study, serial dilutions of the extract were prepared in two sets of 10 test tubes for each bacterium (total of 20). Standard amounts of bacterial suspension were added; 100ƛof each tube was cultured on prepared solid agar plates and incubated at 37°C for 24 hours. Serial dilutions of the extract were prepared in another 20 tubes and 100ƛof each tube was added to blood agar culture medium while being prepared. The mixture was transferred to the plates. The bacteria were inoculated on plates and incubated as described.Results. The minimum inhibitory concentration (MIC) was 0.02 mg/mL forS. mutansand 0.3 mg/mL forS. sanguinis. The minimum bactericidal concentration (MBC) was 0.04 mg forS. mutansand 0.6 mg forS. sanguinis.Conclusion.Zingiber officinaleextract has significant antibacterial activity againstS. mutansandS. sanguiniscariogenic microorganisms.

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