4 research outputs found
Genetic architecture of purple pigmentation and tagging of some loci to SSR markers in pearl millet, Pennisetum glaucum (L.) R. Br.
This report describes the construction of integrated genetic maps in pearl millet involving certain purple phenotype and simple sequence repeat (SSR) markers. These maps provide a direct means of implementing DNA marker-assisted selection and of facilitating âmap-based cloningâ for engineering novel traits. The purple pigmentation of leaf sheath, midrib and leaf margin was inherited together âen blocâ under the control of a single dominant locus (the âmidrib complexâ) and was inseparably associated with the locus governing the purple coloration of the internode. The purple panicle was caused by a single dominant locus. Each of the three characters (purple lamina, purple stigma and purple seed) was governed by two complementary loci. One of the two loci governing purple seed was associated with the SSR locus Xpsmp2090 in linkage group 1, with a linkage value of 22 cM, while the other locus was associated with the SSR locus Xpsmp2270 in linkage group 6, with a linkage value of 23 cM. The locus for purple pigmentation of the midrib complex was either responsible for pigmentation of the panicle in a pleiotropic manner or was linked to it very closely and associated with the SSR locus Xpsmp2086 in linkage group 4, with a suggestive linkage value of 21 cM. A dominant allele at this locus seems to be a prerequisite for the development of purple pigmentation in the lamina, stigma and seed. These findings suggest that the locus for pigmentation of the midrib complex might regulate the basic steps in anthocyanin pigment development by acting as a structural gene while other loci regulate the formation of color in specific plant parts
DSC studies on organic melting point temperature standards
A series of organic melting point temperature standards are available for which the liquefaction temperature has been determined by stepwise heating under near equilibrium conditions. The present work explores their use in the accurate calibration of DSC equipment. Two methods have been used, each of which has been shown to have advantages. In the first, a stepwise heating procedure has been adopted which is analogous to that used in calibrating the standards. The final step corresponds to the certified liquefaction temperature. In the alternative procedure the extrapolated onset temperature has been determined for zero heating rate. This work provides experimental confirmation that the extrapolated onset temperature at zero heating rate corresponds to the certified thermodynamic liquefaction temperature
Electrostatically Mediated Attractive Self-Interactions and Reversible Self-Association of Fc-Fusion Proteins
Attractive self-interactions and
reversible self-association are
implicated in many problematic solution behaviors for therapeutic
proteins, such as irreversible aggregation, elevated viscosity, phase
separation, and opalescence. Protein self-interactions and reversible
oligomerization of two Fc-fusion proteins (monovalent and bivalent)
and the corresponding fusion partner protein were characterized experimentally
with static and dynamic light scattering as a function of pH (5 and
6.5) and ionic strength (10 mM to at least 300 mM). The fusion partner
protein and monovalent Fc-fusion each displayed net attractive electrostatic
self-interactions at pH 6.5 and net repulsive electrostatic self-interactions
at pH 5. Solutions of the bivalent Fc-fusion contained higher molecular
weight species that prevented quantification of typical interaction
parameters (B22 and kD). All three of the proteins displayed reversible self-association
at pH 6.5, where oligomers dissociated with increased ionic strength.
Coarse-grained molecular simulations were used to model the self-interactions
measured experimentally, assess net self-interactions for the bivalent
Fc-fusion, and probe the specific electrostatic interactions between
charged amino acids that were involved in attractive electrostatic
self-interactions. Mayer-weighted pairwise electrostatic energies
from the simulations suggested that attractive electrostatic self-interactions
at pH 6.5 for the two Fc-fusion proteins were due to cross-domain
interactions between the fusion partner domain(s) and the Fc domain