Post-testicular change in the reptile sperm surface with particular reference to the snake, Natrix fasciata

Sperm surface changes occurring in the reptile Wolffian duct have been explored with particular references to the snake, Natrix fasciata. In the snake Wolffian duct there are several proteins not present in serum, the pattern of which changes in concert with the seasonal testicular cycle. Whereas testicular spermatozoa did not bind antibody to duct secretions, all Wolffian duct spermatozoa did so over both head and tail, according to immunofluorescence patterns. Thus, on entering the Wolffian duct, the entire surface of N. fasciata spermatozoa acquires one of more of the duct's secretory components. As indicated by immunofluorescence, immunoelectrophoresis, and immunodiffusion, epitopes on at least some molecules that bind to spermatozoa or that remain free in the duct fluid are shared with those in other Natrix species, but not in more distant reptiles (turtle, anole lizard), nor chicken, rat, or rabbit. In regard to glycoproteins, one prominent con A-reactive band was present in polyacrylamide gel electrophoresis (PAGE) of snake fluid and more were evident in fluid collected from the turtle duct. However, such lectin-reactive elements did not bind to spermatozoa as judged by an absence of any change in snake, turtle and lizard sperm lectin-binding patterns in passing from the testis into and through the Wolffian duct. In all, evidence from these and other species studied begins to suggest that the nature of the post-testicular sperm surface modification displayed in most vertebrates that fertilize internally may differ in sub-therian and therian groups, respectively. There appears to be a relative emphasis on glycosyl-rich surface elements in the latter. The possible significance of these changes for sperm function in the different groups is discussed briefly in terms of sperm survival/storage, as well as capacitation and sperm binding to the zona.     

Factors influencing the sensitivity of two human bladder carcinoma cell lines to cis-diamminedichloroplatinum(II)

A two-fold difference in sensitivity to cis-diamminedichloroplatinum(II) (cisplatin), as judged by colony forming assays, has been demonstrated in two human bladder carcinoma continuous cell lines. Approximately twice as many DNA-DNA interstrand cross-links (ISL) and a 2-fold greater inhibition of DNA synthesis occurred in the more sensitive T24 cell line than in the RT112 cell line after exposure to the same concentrations of cisplatin. Equitoxic concentrations of cisplatin resulted in similar extents of ISL and inhibition of DNA synthesis in both cell lines. Although drug uptake was identical, twice as much cisplatin was bound to the DNA of T24 cells than RT112 cells. However after equitoxic concentrations of cisplatin the DNA from both cell lines was platinated to a similar extent. In addition, levels of glutathione (GSH), glutathione reductase (GR) and total glutathione-S-transferases (GST) were higher in the less sensitive RT112 cell line.     

Isolation and characterization of heat-sensitive, thermotolerant defective mutants of CHO cells

A replica plating technique was utilized to isolate stable CHO cell mutants that are heat-sensitive and have altered capacities to develop thermotolerance. From a mutagen (EMS) treated population of CHO cells, two strains were isolated. One (HS-36) shows a greatly reduced ability to develop thermotolerance following an initial 45.0 degrees C heat shock. The other (HS-23) also shows a greatly reduced thermotolerance development following a short 45.0 degrees C induction dose, but a greater thermotolerance development following longer 45.0 degrees C induction doses. The dose-survival response following single-dose 45.0 degrees C heating of HS-23 cells suggests the presence of a resistant subpopulation which is not due to contamination from, or reversion to, wild-type cells. Both strains have unique morphological characteristics. Spheroids develop in the central portion of HS-36 colonies, though cells in monolayers are indistinguishable from wild-type parental cells. HS-23 cells grow in firmly attached monolayers, but more than 95% maintain a "rounded" morphology. The remainder show a "flattened" morphology typical of CHO cells. Both strains have parental CHO characteristics as determined by chromosome number, population doubling times, and survival responses to UV light and to gamma rays. Each has maintained its heat-sensitive and altered thermotolerance phenotype for a period of over 6 months in continuous log-phase culture.     

Phylogenetic distribution in the genus Mus of t-complex-specific DNA and protein markers: inferences on the origin of t-haplotypes

We have examined the phylogenetic distribution of two t-specific markers among representatives of various taxa belonging to the genus Mus. The centromeric TCP-1a marker (a testicular protein variant specific for all t-haplotypes so far studied) has also been apparently detected in several non-t representatives of the Mus IVA, Mus IVB, and probably M. cervicolor species. By contrast, a t-specific restriction- fragment-length polymorphism allele (RFLP) of the telomeric alpha- globin pseudogene DNA marker alpha-psi-4 was found only in animals belonging to the M. musculus-complex species either bearing genuine t- haplotypes or, like the M. m. bactrianus specimen studied here, likely to do so. This t-specific alpha-psi-4 RFLP allele was found to be as divergent from the RFLP alleles of the latter, non-t, taxonomical groups as it is from Mus 4A, Mus 4B, or M. spretus ones. These results suggest the presence of t-haplotypes and of t-specific markers in populations other than those belonging to the M. m. domesticus and M. m. musculus subspecies, implying a possible origin for t-haplotypes prior to the radiation of the most recent offshoot of the Mus genus (i.e., the spretus/domesticus divergence), some 1-3 Myr ago.      

The role of dendritic cells in the initiation of immune responses to contact sensitizers. II. Studies in nude mice

Twenty-four hours after skin painting nude mice with picryl chloride, there was an increase in the number of dendritic cells (DC) isolated from the draining lymph nodes. This increased inflow or retention of DC in lymph nodes following skin painting is therefore unlikely to depend on interaction of DC with T cells. The DC obtained initiated primary proliferative responses in vitro in lymph node cells from congenic euthymic mice. Contact sensitivity developed in congenic mice when they received footpad injections of 60,000 DC from the lymph nodes of nude mice skin sensitized 1 day previously with picryl chloride or oxazolone. The initiation of delayed hypersensitivity was therefore independent of T-cell contamination within the donor DC.     

The cell cycle dependence of thermotolerance. III. HeLa cells heated at 45.0 degrees C

We have extended our studies on the cell cycle dependence of thermotolerance to include HeLa cells heated at 45.0 degrees C to compare the results to Chinese hamster ovary (CHO) cells. We found that asynchronous HeLa cells were more resistant to heat than CHO cells but showed a similar development and decay of thermotolerance. Flow cytometry (FCM) was used to study redistributions in the cell cycle after an initial heat dose. Cells heated for 35 min at 45.0 degrees C were delayed in G1 by about 7 h compared to controls, with delays in late S and G2/M phase also. The heat sensitivity varied through the cell cycle; G1 cells were the most resistant to heat, while S-phase cells were uniformly sensitive throughout S phase, and G2 cells were resistant. Thermotolerance could be induced and expressed in early or late S-phase cells, but to a lesser extent than for G1 cells. The results were similar in many respects to CHO cells, but there were significant differences.