Home About us Contact
|
Home About us Contact | ||
|
|
||
Nutrient Media (nutrient + media)
Selected AbstractsCharacteristics of strawberry plants propagated by in vitro bioreactor culture and ex vitro propagation methodENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2009Samir C. Debnath Abstract Reproducible protocol for regeneration of complete plantlets from ,Bounty' strawberry (Fragaria ananassa Duch.), using a combination of gelled medium and bioreactor system, has been standardized. Sepals, leaf discs, and petiole halves produced multiple buds and shoots when cultured on semi solid-gelled medium containing 4 ,M thidiazuron (TDZ) for 4 wk followed by transferring in liquid medium containing 2,,M TDZ in a bioreactor system and cultured for another 4 wk. TDZ induced shoot proliferation at 0.1,,M in the bioreactor system but inhibited shoot elongation. TDZ-induced shoots were elongated and rooted in vitro on gelled medium containing 2,,M zeatin. Such bioreactor-derived tissue culture (BC) plantlets obtained from sepal explants were grown ex vitro and compared with those propagated by tissue culture on gelled medium (GC) and by conventional runner cuttings (RC), for growth, morphology, anthocyanin content, and antioxidant activity after three growth seasons. The BC and GC plants produced more crowns, runners, leaves, and berries than the RC plants although berry weight per plant did not differ significantly. BC and GC plants produced berries with more anthocyanin contents and antioxidant activities than those produced by the RC plants. However, intersimple sequence repeat (ISSR) marker assay produced a homogenous amplification profile in the tissue culture and donor control plants confirming the clonal fidelity of micropropagated plants. In vitro culture on TDZ and zeatin-containing nutrient media apparently induced the juvenile branching characteristics that favored enhanced vegetative growth with more crown, runners, leaf, and berry production. [source] Characterization of a Vibrio cholerae phage isolated from the coastal water of PeruENVIRONMENTAL MICROBIOLOGY, Issue 5 2003Miguel Talledo Summary A Vibrio cholerae bacteriophage, family Myoviridae, was isolated from seawater collected from the coastal water of Lima, Peru. Genome size was estimated to be 29 kbp. The temperate phage was specific to V. cholerae and infected 12/13 V. cholerae O1 strains and half of the four non-O1/non-O139 strains tested in this study. Vibrio cholerae O139 strains were resistant to infection and highest infection rates were obtained in low nutrient media amended with NaCl or prepared using seawater as diluent. [source] Glutamine Nitrogen and Ammonium Nitrogen Supplied as a Nitrogen Source Is Not Converted into Nitrate Nitrogen of Plant Tissues of Hydroponically Grown Pak-Choi (Brassica chinensis L.)JOURNAL OF FOOD SCIENCE, Issue 2 2009H.-J. Wang ABSTRACT:, Many vegetables, especially leafy vegetables, accumulate NO,3 -N in their edible portions. High nitrate levels in vegetables constitute a health hazard, such as cancers and blue baby syndrome. The aim of this study was to determine if (1) ammonium nitrogen (NH+4 -N) and glutamine-nitrogen (Gln-N) absorbed by plant roots is converted into nitrate-nitrogen of pak-choi (Brassica chinensis L.) tissues, and (2) if nitrate-nitrogen (NO,3 -N) accumulation and concentration of pak-choi tissues linearly increase with increasing NO,3 -N supply when grown in nutrient solution. In experiment 1, 4 different nitrogen treatments (no nitrogen, NH+4 -N, Gln-N, and NO,3 -N) with equal total N concentrations in treatments with added N were applied under sterile nutrient medium culture conditions. In experiment 2, 5 concentrations of N (from 0 to 48 mM), supplied as NO,3 -N in the nutrient solution, were tested. The results showed that Gln-N and NH+4 -N added to the nutrient media were not converted into nitrate-nitrogen of plant tissues. Also, NO,3 -N accumulation in the pak-choi tissues was the highest when plants were supplied 24 mM NO,3 -N in the media. The NO,3 -N concentration in plant tissues was quadratically correlated to the NO,3 -N concentration supplied in the nutrient solution. [source] Phytase-producing bacteria in the digestive tracts of some freshwater fishAQUACULTURE RESEARCH, Issue 3 2009Tanami Roy Abstract Isolation and enumeration of phytase-producing bacterial flora in the foregut and hindgut regions of the gastrointestinal tracts of 10 culturable freshwater teleosts of different feeding habits, namely rohu (Labeo rohita), catla (Catla catla), mrigal (Cirrhinus mrigala), bata (Labeo bata), kalbasu (Labeo calbasu), Nile tilapia (Oreochromis niloticus), climbing perch (Anabas testudineus), common carp (Cyprinus carpio), silver carp (Hypophthalmichthys molitrix) and grass carp (Ctenopharyngodon idella), have been carried out. Microbial culture of the gut mucosa on selected nutrient media following the enrichment culture technique was performed for bacterial isolation. The bacterial isolates were screened on the basis of their enzyme-producing ability. The bacterial population on the tryptone soya agar (TSA) plate was maximum in the hindgut region of bata, followed by mrigal and minimum in the foregut region of Nile tilapia. In modified phytase screening medium (MPSM), phytase-producing strains were recorded at higher densities in the foregut region of mrigal and grass carp and minimum in the foregut region of bata. In case of the hindgut, maximum phytase-producing strains were present in grass carp and mrigal and minimum in rohu. In general, in MPSM, the bacterial population was lower in the hindgut region of all the 10 species of fish examined. The phytase-producing ability of the selected 31 strains (16 from the foregut and 15 from the hindgut region) was determined by clearing zones on phytate-containing plates. Among these isolates, 22 strains (12 from the foregut and 10 from the hindgut region) were selected as potent phytase producers according to a quantitative enzyme assay. The highest phytase activity was observed in the bacterial strains LF1 and LH1 isolated from the fore and the hindgut regions of rohu respectively. Both the strains were identified as Bacillus licheniformis on the basis of phenotypic characteristics as well as 16S rDNA sequence analysis. [source] | ||||||||||