Many crops are colonized with arbuscular mycorrhizae fungi (AMF), which can efficiently absorb nutrient from the soil and induce plant immunity. The purpose of this study was to investigate the effects of AMF and rock phosphate (P) fertilizer applications on available P and some secondary plant metabolite in robusta coffee. The experiments were laid out in a 3 × 4 factorial randomized complete block design with AMF inoculants (control, Glomus intraradices LU3, Glomus sp. 2TS5) and rock phosphate fertilizer levels (0, 100, 200, and 400 g plant −1 ). Parameters measured root colonization percentage, available P in soil, total P in leaf, salicylic acid and phenolic compounds in leaves. The results showed that there was significant interaction between AMF and P in root colonization density, available P in soil, total P in leaves, and salicylic acid content. AMF (both Glomus intraradices and Glomus sp.) improved root colonization density (64-65%), available P in soil (30-50%), total P in leaves (37-40%), salicylic acid content (8-19%), and phenolic compounds in leaves (53-74%) compared to the control. Also, higher P at 400 g plant −1 increased root colonization density, available P in soil, total P accumulation in leaves, and salicylic acid. Therefore, AMF and rock P potentially represent an alternative way to promoting P uptake and plant immune in coffee.
The strain PNR11 was isolated from gut of termite during the screening for uric acid degrading actinomyces. This strain was able to produce an intracellular uricase when cultured in fermentation medium containing uric acid as nitrogen source. Base on its morphological characters and 16S rDNA sequence analysis, this strain belong to the genus Saccharopolyspora. This is the first report ofuricase produced from the genus Saccharopolyspora. The aim of this study was to investigate the effects of different factors on uricase production by new source of Saccharopolyspora. Saccharopolyspora sp. PNR11 was cultured in production medium in order to determine the best cultivation period. The result showed that the time period required for maximum enzyme production was 24 h on a rotary shaker operating at 180 rpm. Optimized composition of the production medium consisted of 1% yeast extract, 1% maltose, 0.1% K2HPO4, 0.05% MgSO4 7H2O, 0.05% NaCl and 1% uric acid. The optimum pH and temperature for uricase production in the optimized medium were pH 7.0 and 30 degrees C, respectively. When the strain was cultured at optimized condition, the uricase activity reached to 216 mU mL(-1) in confidential level of 95%. The crude enzyme had an optimum temperature of uricase was 37 degrees C and it was stable up to 30 degrees C at pH 8.5. The optimum pH ofuricase was 8.5 and was stable in range of pH 7.0-10.0 at 4 degrees C. This strain might be considered as a candidate source for uricase production in the further studies. Present finding could be fulfill the information ofuricase produce from actinomycetes.
Morphological and chemotaxonomic characterization of actinomycete strain S582 isolated from the gut of a termite (Speculitermes sp.) in Pathum Thani Province, Thailand, clearly demonstrated that this strain is a member of the genus Saccharopolyspora. 16S rDNA sequence analysis for the strain supported the assignment of the strain to the genus Saccharopolyspora. The similarity value of sequences between this strain and the closely related species Saccharopolyspora endophytica was 99.5%. The DNA G+C content was 70.2 mol%. DNA DNA hybridization results (53.3%) and some physiological and biochemical properties indicated that strain S582 T was distinguished from the phylogenetically closest relatives. Based on these genotypic and phenotypic data, strain S582 T should be a new species in the genus Saccharopolyspora and the name Saccharopolyspora pathumthaniensis sp. nov. is proposed for the strain. The type strain is S582 T (=NBRC 104112 T =BCC 28624 T ).
An extracellular thermostable xylanase produced by Saccharopolyspora pathumthaniensis S582 was purified 167-fold to homogeneity with a recovery yield of 12%. The purified xylanase appeared as a single protein band on SDS-PAGE, with a molecular mass of 36 kDa. The optimal temperature and pH of the xylanase were 70 °C and 6.5. The enzyme was stable within a pH range of 5.5-10.0. It retained its activity after incubation at 50 °C for 2 h. Its half lives at temperatures of 60 and 70 °C were 180 and 120 min respectively. Hydrolysis of beechwood xylan by the xylanase yielded xylobiose and xylose as major products. The enzyme acted specifically on xylan as an endo-type xylanase, and exhibited a K(m) value of 3.92 mg/mL and a V(max) value of 256 µmol/min/mg. Enzyme activity was completely inhibited by Hg(2+), and was stimulated by Rb(+) and Cs(+). The xylanase gene was cloned from genomic DNA of Saccharopolyspora pathumthaniensis S582 and sequenced. The ORF consisted of 1,107 bp and encoded 368 amino acid residues containing a putative signal peptide of 23 residues. This xylanase is a new member of family (GH) 10 that shows highest identity, of 63.4%, with a putative xylanase from Nocardiopsis dassonvillei subsp. dassonvillei.
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