Electrophoretic Mobility Of Protein Research Articles

Isolation and characterization of major outer membrane proteins of Pseudomonas aeruginosa strain PAO with special reference to peptidoglycan-associated protein.

The outer membrane of Pseudomonas aeruginosa PAO contains six major proteins (proteins D, E, F, G,H, and I). Two of them (protein F and protein H) were found to be retained by the peptidoglycan layer when cell envelopes were extracted with 2% sodium dodecyl sulfate (SDS) solution at 35 degrees C. At higher temperature (greater than 55 degrees C), no proteins were retained by peptidoglycan. By making use of this property, purification of protein F and protein H was achieved. Three other major outer membrane proteins, D, E, and I were also isolated and characterized. Their amino acids compositions were determined. Circular dichroism spectra of these isolated proteins were measured in SDS solution. Protein F was rich in beta-structure, while protein I was rich in alpha-helix. When isolated protein F was heated (100 degrees C-15 min) in SDS solution, the circular dichroism spectrum changed significantly. In parallel with the conformational change, the electrophoretic mobility of protein F on urea-SDS polyacrylamide gel also changed. These results indicate that protein F is a so-called heat-modifiable protein.

Close Relationship between the Lizard Genus Sator and Sceloporus utiformis (Reptilia, Lacertilia, Iguanidae): Electrophoretic and Immunological Evidence

Horizontal starch gel electrophoresis was employed in analysis of lactic dehydrogenase isozymes for two species of Sator, 22 species of Sceloporus, and representatives of all other sceloporine genera. Sator was compared electrophoretically to 12 species of Sceloporus for six additional presumptive gene loci. Albumin of Sator was compared immunologically to 38 species of Sceloporus and representatives of all other sceloporine genera. The findings indicate a close genetic relationship between the two insular species of Sator and the mainland Mexican Sceloporus utiformis. * * * The lizard genus Sator is comprised of two species restricted to three islands in the Gulf of California: Sator grandaevus on Cerralvo, and Sator angustus on Santa Cruz and San Diego islands. Sator is the only recognized endemic genus of terrestrial vertebrates restricted to the Gulf of California islands. Clarification of its phylogenetic relationships is important to furthering our understanding of the historical and ecological biogeography of the Baja California peninsula and its associated islands. Its present distribution suggests that it is a relict, and there are strong implications of competitive exclusion. On the three islands where it occurs, Uta, Urosaurus, and Sceloporus are all absent, although at least one member of these three genera occurs on virtually all other Gulf islands (Soule and Sloan, 1966). Since the description of Sator by Dickerson (1919), the taxonomic and biogeographic status of this genus has aroused interest. Dickerson believed that the affinities of Sator were with mainland Mexican Sceloporus of the utiformis group. Subsequent analyses of the relationships of Sator have dealt with morphological characters (Etheridge, 1962, 1964; Larsen and Tanner, 1975; Mittleman, 1942; Savage, 1958). This study provides additional evidence based upon independent sets of characters, electrophoretic mobilities of proteins and immuno- logical distances of serum albumins.

Partial characterization of the structural proteins of sonchus yellow net virus

Sonchus yellow net virus (SYNV) proteins separate into four major and three minor proteins during polyacrylamide gel electrophoresis (PAGE). The major proteins consist of a glyoprotein (G), a nucleoprotein (N), and two proteins thought to be membrane proteins (M-1 and M-2). Minor proteins include two or three high molecular weight proteins (L) and a protein (possibly NS) with an electrophoretic mobility near the N protein. Proteins of potato yellow dwarf virus (PYDV) are similar in number and staining intensity to those of SYNV after PAGE, but the electrophoretic mobilities of proteins from the two viruses differ. SYNV dissociates with 2% Triton X-100 in 0.4 M NaCl at pH 7.5 to produce a 250 S nucleoprotein core plus solubilized L, G, and M proteins. A 200 S core is released at pH 7.5 in 0.8 M NaCl or at pH 8.4 in 0.4 or 0.8 M NaCl. The 250 S core contains all of the N protein and some undissociated L, G, and M proteins, but the 200 S core contains N protein and only traces of the L, G, and M proteins. After fixation with glutaraldehyde and negative staining, both 200 and 250 S cores are loosely coiled strands with a helical structure. The cores are infectious after being treated with detergent and separated on sucrose gradients, but the infectivity is considerably less than intact virus preparations. Iodination patterns of intact and detergent-disrupted virions suggest that L and G proteins are on the exterior of the virion, that M-2 is partially exposed on the virion surface, and that M-1 and N proteins are located beneath the surface of the virion.

BOTTLENECK EFFECTS ON AVERAGE HETEROZYGOSITY AND GENETIC DISTANCE WITH THE STEPWISE MUTATION MODEL.

When a population goes through a small bottleneck, the genetic variability of the population is expected to decline rapidly, but as soon as population size becomes large, it starts to increase owing to new mutations (Wright, 1931; Mayr, 1954). Recently, Nei et al. (1975) studied this problem mathematically and showed that the pattern of change in genetic variability largely depends on the size of bottleneck, rate of population growth, and mutation rate. They provided a general formula for computing the average heterozygosity per locus in a population of changing size. This study is based on the assumption that new mutations occurring in a population are always different from the preexisting ones (Kimura and Crow's (1964) infinite allele model). This assumption seems to be roughly correct if allelic differences are studied at the nucleotide or codon level. In practice, however, the genetic variability of natural populations is usually studied by electrophoretic mobility of proteins. Electrophoretic mobility of a protein is determined mainly by the net charge of the protein, and a positive or negative change in the net charge due to an amino acid substitution may be canceled by the second opposite charge change. Therefore, strictly speaking, the infinite allele model is not appropriate for the study of protein variation detected by electrophoresis. In view of this circumstance, Ohta and Kimura (1973) introduced the so-called stepwise mutation model. In this model each allele is represented as one of the infinite sequence of allelic states and mutation is assumed to produce a one-step change in either the positive or the negative direction. They derived a formula for average heterozygosity in an equilibrium population. Later, Wehrhahn (1975) and Li (1976) extended Ohta and Kimura's work to the case of nonequilibrium populations. On the other hand, Nei and Chakraborty (1973) studied the expected genetic distance between two populations when these are separated for an arbitrary number of generations, using a similar genetic model. The purpose of the present paper is to study the bottleneck effects on average heterozygosity and genetic distance by using the stepwise mutation model. Some studies on the bottleneck effect (the effect of reduction in population size) on genetic distance have been made by Chakraborty and Nei (1974) and Nei (1976), using the infinite allele model. These authors have shown that the reduction in population size results in an accelerated increase in genetic distance in the early generations. In the present paper we shall employ the method of generating function first used by Nei and Chakraborty (1973) in the study of protein variation and extended considerably by Wehrhahn ( 19 7 5).

Comparative study of protein pattern of epididymal plasma of mouse, rat, rabbit and sheep

1.1. The protein pattern of epididymal plasma like fluid (EPLF) of mouse, rat, rabbit and sheep was revealed by acrylamide disc gel electrophoresis.2.2. Based on the electrophoretic mobility of proteins in EPLF and proteins in blood serum, it is suggested that blood serum is the main source of most of the EPLF protein.3.3. There are many epididymal plasma unique proteins appearing in the protein picture of each species.4.4. The number of epididymal plasma unique proteins is mouse, 3 and 2; rat, 5 and 2; rabbit, 5 and 5; and sheep, 5 and 5, for basic and acidic pH, respectively.

Modification of ribosomal proteins during liver regeneration

Analysis of the 2D gel electrophoretic pattern of ribosomal proteins from both the small and large subunit of rat liver were made at various times following partial hepatectomy. No changes were observed in the electrophoretic mobility of proteins from the 60S subunit during periods of 2 hr. to 72 hr. of liver regeneration. Changes were observed, however, in two proteins of the 40S subunit a short time after partial hepatectomy. Protein S 6 disappeared from its normal position and a new spot appeared as a more negative form as early as 2 hr. post regeneration. This modification persisted for at least 18 hr. At 72 hr., S 6 returned to its normal position. Protein S 2, on the other hand, underwent a different pattern of change during the early stages of liver regeneration. S 2 was observed to migrate as 2 spots at 2 hr. after partial hepatectomy and this pattern was preserved at the 4 hr. period. At 8 hr., the pattern was further modified to 2 spots which was distinct from the earlier change. This pattern was similar at 12 hr. At 18 hr. only the normal S 2 protein was observed. No further change in S 2 migration was observed at the 72 hr. period of liver regeneration.

Analysis of polypeptide molecular weights by electrophoresis in urea

Ten proteins of differing disulfide contents and isoionic points were subjected to disc gel electrophoresis in the presence of 8 m urea-0.9 m acetic acid to evaluate the use of this technique in determining polypeptide molecular weights. Comparison of the electrophoretic mobilities before and after reduction of the proteins' disulfide bonds demonstrated that only after all disulfide bonds were broken, could their molecular weights be estimated with any degree of accuracy. The expression of the electrophoretic mobilities as a function of the proteins' effective hydrodynamic sizes, thereby taking into account the extent of constraint by disulfide bonds, allowed a comparison of disulfide cross-linked and linear forms of the protein polypeptides. The extent to which intrinsic charge affects a protein's electrophoretic mobility was estimated by comparing alpha-lactalbumin and lysozyme, two proteins of identical size but vastly different isoionic points. They exhibited a 20% difference in mobilities. An apparent slow reduction of disulfide bonds was observed to occur when proteins were exposed to reducing agent at low pH in 8 m urea.

Estimate of genetic polymorphism and heterozygosity in three species of rockfish (Genus Sebastes)

1. 1. An estimate of the genetic polymorphism and average hetorozygosity in three species of rockfish, Sebastes alutus, S. caurinus, and S. elongatus' was made using differences in electrophoretic mobility of proteins on starch gel. 2. 2. In S. alutus two of twenty-five loci; in S. caurinus, one of twenty-five loci; and in S. elongatus, two of twenty-four loci were polymorphic. 3. 3. This yields estimates of 8,4 and 8 per cent of all polymorphic for the average species population and values of 3·8, 1·8 and 3·3 per cent for the proportion of the genome heterozygous per individual in the average population.

An electrophoretic study of lactate dehydrogenase isoenzymes, protein and lipoprotein of Drosophila melanogaster larvae, pupae and adults

1. 1. Anodal polyacrylamide-gel electrophoresis of Drosophila melanogaster larvae , pupae and adults has shown lactate dehydrogenase (LDH) to consist of six, three and six isoenzymes, respectively. 2. 2. In terms of electrophoretic mobility, LDH-6 of adults corresponds to LDH-3 of pupae, and LDH-1 and 4 of adults correspond to LDH-1 and 5 of larvae, respectively. 3. 3. These results suggest the possibility of a dimeric structure for LDH in larvae and pupae, and that different loci are responsible for synthesis of LDH in these two life-cycle stages. 4. 4. A combination of the loci that are active in larvae and pupae may be responsible for LDH synthesis in adults. 5. 5. Dramatic differences were found when the protein and lipoprotein banding patterns of larvae, pupae and adults were compared. 6. 6. These differences were manifest in changes in the number, density and electrophoretic mobility of protein and lipoprotein bands.

ELECTROPHORESIS OF PROTEINS IN NATURAL POPULATIONS OF PARTULA (GASTROPODA).

The evolutionary relationships among species of the genus Partula are complex and by no means well understood (Crampton, 1932; Lundman, 1947; Bailey, 1956). These highly polymorphic land snails inhabit the volcanic islands of the Pacific from the Austral Islands in the southeast to the Marianas in the northwest. Each island group has its own endemic species, and most of the species display an elaborate polymorphism in color and pattern of the shell (Crampton, 1916, 1932; Murray and Clarke, 1966). Although it is relatively small, measuring only 10 miles across at the widest point, the island of Moorea (see map, Murray and Clarke, 1968) in French Polynesia is particularly rich in variation. Crampton (1932) recognized ten species of different degrees of distinctiveness. One of these, Partula suturalis Pfeiffer, is of particular interest. It is widespread, common, highly polymorphic, and related rather closely to several other species on the island. Murray and Clarke (1968) have presented evidence that its relationship with P. aurantia Crampton is particularly complex. Using rank correlation methods they have shown that there are constellations of characters associated with each species, indicating that in some populations the two are distinct. In other populations, however, the breakdown of correlation shows that reproductive isolation between them is incomplete. In an attempt to cast more light on the relationships in what may be called the P. suturalis species group, the electrophoretic mobility of proteins from individuals of the group was studied using the tech-

Effect of removal of lymphatic tissue on immune response in mice

Extensive lymphatic tissue removal in mice prolonged skin homograft survival as long as 32 days in one animal, but the longest median rejection time for a given experiment was 17 days. The longest homograft survival in sham-operated controls was 14 days; median rejection time was 10 days. A median rejection time of 18 days was seen in a few mice given 400 r after the extensive lymphatic tissue removal. When second set homograft response was studied there was no significant effect of the tissue removal. Extensive lymphatic tissue removal markedly reduced the serum antibody response to a small dose of sheep RBC antigen for both the primary and secondary responses. Relatively little recovery of ability to respond was seen with the primary response during the 18-day period of observation. Lymphatic tissue removal did not alter the serum protein electrophoretic mobility pattern. Little compensatory hyperplasia of residual or ectopic lymphatic tissue was seen at the completion of the experiments. Regeneration of lymphatic tissue did not take place at operative sites except near the pancreas where complete extirpation of lymph nodes was difficult to perform.