Interaction-induced quantum phase revivals and evidence for the transition to the quantum chaotic regime in 1D atomic Bloch oscillations.

We study atomic Bloch oscillations in an ensemble of one-dimensional tilted superfluids in the Bose-Hubbard regime. For large values of the tilt, we observe interaction-induced coherent decay and matter-wave quantum phase revivals of the Bloch oscillating ensemble. We analyze the revival period dependence on interactions by means of a Feshbach resonance. When reducing the value of the tilt, we observe the disappearance of the quasiperiodic phase revival signature towards an irreversible decay of Bloch oscillations, indicating the transition from regular to quantum chaotic dynamics.

Plasminogen activator production and enhanced development in medium containing plasminogen or plasmin by rabbit embryos in vitro.

A series of experiments was conducted to evaluate plasminogen activator production and effects of supplementing culture medium with plasminogen or plasmin on development of rabbit embryos in vitro. In Expt 1, 495 one- to two-cell embryos were cultured in Ham's F-12 with 15 mg BSA ml-1 containing 0, 30, 60 or 120 micrograms porcine plasminogen ml-1 or 0, 75, 150 or 300 micrograms rabbit plasminogen ml-1. Percentages of embryos developing to the expanded blastocyst, hatching blastocyst and hatched blastocyst stages were greater (P < 0.05) in medium with 120 micrograms porcine plasminogen ml-1 than in the absence of plasminogen. More (P < 0.05) embryos developed to the blastocyst, expanded blastocyst and hatching blastocyst stages in medium with 300 micrograms rabbit plasminogen ml-1 than in the absence of plasminogen. In Expt 2, 216 one- to two-cell embryos were cultured in medium with 0, 30, 60 or 120 micrograms porcine plasminogen ml-1 for 96 h, fixed and strained with haematoxylin and eosin, and the number of cells determined. No differences (P > 0.05) were observed in number of cells of morulae but blastocysts developing in medium with 120 micrograms porcine plasminogen ml-1 had more (P < 0.05) cells (109.9 +/- 10.4) than did blastocysts in medium with either 0 (69.4 +/- 14.6) or 30 micrograms porcine plasminogen ml-1 (73.3 +/- 12.2). In Expt 3, 144 one- to two-cell embryos were cultured in medium with 0, 13 or 45 micrograms porcine plasmin ml-1 or 120 micrograms porcine plasminogen ml-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium/potassium adenosine triphosphatase alpha-subunit and alpha-subunit mRNA levels in early rabbit embryos.

Sodium/potassium adenosine triphosphatase (Na+/K+ ATPase) and Na+/K+ ATPase mRNA content of rabbit embryos during preimplantation development were evaluated. Changes in Na+/K+ ATPase alpha-subunit content were detected with Western blotting using polyclonal antiserum against guinea pig Na+/K+ ATPase. Total RNA samples from rabbit embryos were analyzed by using Northern blots hybridized with random primer-labeled cDNA for Na+/K+ ATPase alpha-subunit from sheep kidney. Northern blots exhibited a single mRNA band (3.65 kilobases) in sheep kidneys and rabbit embryos. Between Day 4 and Day 6 of development, Na+/K+ ATPase alpha-subunit mRNA content increased 35-fold whereas Na+/K+ ATPase alpha-subunit content increased 22-fold. The similar increase in Na+/K+ ATPase alpha-subunit mRNA and alpha-subunit content in rabbit embryos suggests that Na+/K+ ATPase is partly regulated at the mRNA level during blastocyst expansion.

The effects of plasminogen on in vitro ovine embryo development.

Plasminogen activator production by ovine embryos and the effects of plasminogen on ovine embryo development and zona pellucida integrity were evaluated. Eight-cell to sixteen-cell embryos were cultured in Whitten's medium containing 0, 60, or 120 micrograms/ml plasminogen. Plasmin and plasminogen activator concentrations in the medium were determined by a caseinolytic assay. More blastocysts hatched in medium containing 60 and 120 micrograms/ml plasminogen (33 and 21%, respectively) than 0 microgram/ml plasminogen (0%; p less than 0.05). Zona pellucida dissolution time in acidified phosphate-buffered saline was less after incubation in medium with 60 and 120 micrograms/ml plasminogen (7.2 and 5.9 min, respectively) than 0 microgram/ml plasminogen (9.4 min; p less than 0.05). Plasminogen activator production was low until the morula stage, increased during morula-blastocyst transition, and remained elevated through blastocoelic expansion and hatching. Zona pellucida solubility, plasminogen activator production, and plasminogen conversion to plasmin increased as embryonic stage advanced; however, plasminogen activator production and plasmin conversion to plasmin were poorly correlated with zona pellucida solubility. The results indicate that ovine embryos produce plasminogen activator, and plasmin can increase zona pellucida solubility; however, other factors may also be involved in altering zona pellucida integrity prior to hatching.