Growth medium

About: Growth medium is a research topic. Over the lifetime, 1889 publications have been published within this topic receiving 59171 citations. The topic is also known as: culture medium & culture media.

Chromium tolerance, oxidative stress response, morphological characteristics, and FTIR studies of phytopathogenic fungus Sclerotium rolfsii

Abstract: Sclerotium rolfsii is one of the most destructive fungal plant pathogens that can infect over 500 plants and can adapt to diverse environmental conditions. The present research work was carried out to evaluate the impact of both hexa- and trivalent chromium (Cr) on growth, morphology, enzymatic characteristics, and metal accumulation in S. rolfsii under laboratory conditions. Experiments were performed in both malt extract broth and agar growth medium amended with six different concentrations (10, 20, 40, 60, 80, and 100 ppm) of each Cr(III) and Cr(VI) ions inoculated with fungus and incubated for 6–7 days at 25 ± 3 °C. In broth medium, the total protein content was declined and activities of antioxidant enzymes were increased with an increase in metal concentrations. Lower concentrations (10 ppm) of the metal ions stimulated the growth of fungus and higher concentrations (60–100) inhibited it. The Fourier transform infrared spectroscopy (FTIR) assessment showed hydroxyl, carboxyl, and amine groups as major metal binding sites. In agar medium, tolerance index was decreased up to 0.56 at 10–80 ppm of Cr(III) and up to 0.62 at 10–60 ppm of Cr(VI). Considerable modifications were observed in hyphal and sclerotial morphology with an increase in concentration of metal ions. The current study concluded that interference of Cr with growth and physiological process of S. rolfsii could affect its infection level on its host plant. This study provides important information regarding cultivation of susceptible plant varieties in Cr-polluted soil as evidenced by pathogen growth up to 50 ppm of Cr(III) and Cr(VI) ions.

Growth promotion of Chlorella vulgaris by modification of nitrogen source composition with symbiotic bacteria, Microbacterium sp. HJ1

Abstract: To increase algal growth in treated livestock waste water, we designed a culture system targeting symbiotic bacteria. Microbacterium sp. HJ1 is a symbiotic bacteria associated with Chlorella vulgaris , which was found to increase the growth rate when controlled by nitrogen addition. The validated analysis model for nitrogen source mixture was used to analyze the growth and final pH of Microbacterium sp. HJ1, in different compositions of nitrogen sources, by elucidating the functions of each nitrogen ions such as NO 3 − , NO 2 − , and NH 4 + . By modifying the growth medium made from treated livestock waste water with additional nitrogen source, we were able to increase dry cell weight (DCW) of C. vulgaris by 65.7% and chlorophyll a contents by 78.8%. This is an example of an indirect method to increase algal biomass by changing the population of symbiotic bacteria, and it is the practical application of positive effects from symbiotic bacteria to the host.

Factors affecting dormancy, germination, and seedling development of aeginetia indica l. (orobanchaceae)

Abstract: A B S T RA CT Dormancy in seeds of the parasitic phanerogam Aeginetia indica L. can be broken by chemical treatment with sodium hypochlorite, which also helps to control contaminating microflora. A germination medium was developed that suppressed microbial contamination and permitted long-term observation of these slow-germinating seeds. The medium consisted of 10 ppm streptomycin, 10 ppm penicillin, and 10-' M indole-3-acetic acid (IAA) (or other growth regulator) in 1 % water agar. Optimum germination range was 25-30 C. Dormancy could also be broken by exposure on agar for several days at 3-5 C (stratification), or by brief exposures (15 min) to 50 C. Continuous light as low as 0.1 ft-c completely inhibited germination on this growth medium. Brief, intermittent light exposures depressed germination. Germination and growth in vitro of nondormant seed of Aeginetina indica L. can be described in five stages: (1) Germination: expansion of spheroidal cells or nodule at micropylar end of the seed, stimulated

Age-dependent changes in extracellular proteins, aminopeptidase and proteinase activities in Frankia isolate BR.

Abstract: SUMMARY: To investigate protein secretion by the nitrogen-fixing actinomycete Frankia isolate BR, we designed a rapid DEAE adsorption, salt elution and Biogel P6DG desalination method to concentrate protein from the growth medium. Secreted proteins reached a maximum concentration (5·6 mgl-1) in the medium at growth arrest. Analysis by SDS-PAGE detected up to 63 extracellular polypeptides when Frankia cells were grown under stirred conditions in BAP medium supplemented with phosphatidylcholine and MES buffer and 65 proteins in stirred BAP media alone. The pattern of extracellular polypeptides changed during growth. Several extracellular proteolytic activities were detected and compared with intracellular ones. The substrate specificity of the extracellular and intracellular aminopeptidase activities were the same. Also, the electrophoretic migration patterns of secreted and intracellular aminopeptidases could not be distinguished. Secretion of the proline-specific aminopeptidase FAP 3.BR appeared to be the only one that arrested at the end of the exponential phase of growth. At least 15 proteinases (PF) were secreted: 10 had the same electrophoretic mobility as their intracellular counterparts after SDS-gelatine-PAGE while five (PF-39·5, PF-38·5, PF-36·5, PF-25·5 and PF-20·5 kDa) had a different electrophoretic mobility and, therefore, appeared to be exclusively extracellular. At least seven extracellular proteinases appeared to increase coordinately in activity shortly before growth arrest.