12 research outputs found
Path and Ridge Regression Analysis of Seed Yield and Seed Yield Components of Russian Wildrye (Psathyrostachys juncea Nevski) under Field Conditions
The correlations among seed yield components, and their direct and indirect
effects on the seed yield (Z) of Russina wildrye (Psathyrostachys
juncea Nevski) were investigated. The seed yield components:
fertile tillers m-2 (Y1), spikelets per fertile tillers
(Y2), florets per spikelet- (Y3), seed
numbers per spikelet (Y4) and seed weight (Y5) were
counted and the Z were determined in field experiments from 2003 to 2006 via big
sample size. Y1 was the most important seed yield component
describing the Z and Y2 was the least. The total direct effects of
the Y1, Y3 and Y5 to the Z were positive while
Y4 and Y2 were weakly negative. The total effects
(directs plus indirects) of the components were positively contributed to the Z
by path analyses. The seed yield components Y1, Y2,
Y4 and Y5 were significantly (P<0.001) correlated
with the Z for 4 years totally, while in the individual years, Y2
were not significant correlated with Y3, Y4 and
Y5 by Peason correlation analyses in the five components in the
plant seed production. Therefore, selection for high seed yield through direct
selection for large Y1, Y2 and Y3 would be
effective for breeding programs in grasses. Furthermore, it is the most
important that, via ridge regression, a steady algorithm model between Z and the
five yield components was founded, which can be closely estimated the seed yield
via the components
Purification of an alpha amylase from Aspergillus flavus NSH9 and molecular characterization of its nucleotide gene sequence
In this study, an alpha-amylase enzyme from a locally isolated Aspergillus flavus NSH9 was purified and characterized. The extracellular α-amylase was purified by ammonium sulfate precipitation and anion-exchange chromatography at a final yield of 2.55-fold and recovery of 11.73%. The molecular mass of the purified α-amylase was estimated to be 54 kDa using SDS-PAGE and the enzyme exhibited optimal catalytic activity at pH 5.0 and temperature of 50 °C. The enzyme was also thermally stable at 50 °C, with 87% residual activity after 60 min. As a metalloenzymes containing calcium, the purified α-amylase showed significantly increased enzyme activity in the presence of Ca2+ ions. Further gene isolation and characterization shows that the α-amylase gene of A. flavus NSH9 contained eight introns and an open reading frame that encodes for 499 amino acids with the first 21 amino acids presumed to be a signal peptide. Analysis of the deduced peptide sequence showed the presence of three conserved catalytic residues of α-amylase, two Ca2+-binding sites, seven conserved peptide sequences, and several other properties that indicates the protein belongs to glycosyl hydrolase family 13 capable of acting on α-1,4-bonds only. Based on sequence similarity, the deduced peptide sequence of A. flavus NSH9 α-amylase was also found to carry two potential surface/secondary-binding site (SBS) residues (Trp 237 and Tyr 409) that might be playing crucial roles in both the enzyme activity and also the binding of starch granules. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature
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HD28 .M414 no.4051-99 1999,