Differential expression of LacdiNAc sequences (GalNAc{beta}1-4GlcNAc-R) in glycoproteins synthesized by Chinese hamster ovary and human 293 cells

The lacdiNAc sequence GalNAcß1     

Identification of screwworm species by polymerase chain reaction-restriction fragment length polymorphism

Abstract. Restriction fragment length polymorphisms in polymerase chain reaction amplified fragments (PCR-RFLP) of mitochondrial DNA were used to differentiate species of New World screwworms (Diptera: Calliphoridae). Twenty-seven restriction enzymes were screened on five regions of mtDNA. Eleven restriction fragment length patterns differentiated New World screwworm, Cochliomyia hominivorax (Coquerel), from secondary screwworm, Cochliomyia macellaria (R). Five restriction fragment length patterns were polymorphic in C. hominivorax while all fragment patterns were fixed in C. macellaria. Diagnostic restriction fragment length patterns were used for species diagnosis, whereas intraspecific variable patterns were used to characterize field samples and laboratory strains. The PCR-RFLP technique is flexible with regard to developmental stage of the sample and method of preservation. We were able to characterize specimens of all life stages from egg to adult including larvae preserved in alcohol and pinned adults. PCR-RFLP is rapid and inexpensive, enabling specimens to be characterized within 24 h for less than 2.50.     

Classification of the Environment of Protein Residues

We have studied the classification of the environment of residues within protein structures. Eisenberg's original idea created environmental categories to discriminate between similar residues [Bowie et al., Science (1991), 253, 164–170]. These environments grouped residues based upon their buried surface area, polarity of the surrounding environment, and secondary structure element in which the residue is found. However, Eisenberg's original categories led to incomplete discrimination between residues that only partially substitute for each other. We have expanded on Eisenberg's original idea of environmental categories, by both considering additional contacts in the calculation of the solvent-accessible molecular surface area and by subdividing the environmental plot into regions based upon its theoretical features. Our alternative surface area calculations were used in conjunction with the polarity of the environment of the residue to define a new set of environmental categories. These new categories were able to discriminate between residues such as threonine, valine, and aspartic acid while reflecting the propensity of these residues to substitute for each other.